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Kumar A, Jayawardena D, Priyamvada S, Anbazhagan AN, Chatterjee I, Saksena S, Dudeja PK. SLC26A3 (DRA, the Congenital Chloride Diarrhea Gene): A Novel Therapeutic Target for Diarrheal Diseases. Cell Mol Gastroenterol Hepatol 2024; 19:101452. [PMID: 39736385 PMCID: PMC12003007 DOI: 10.1016/j.jcmgh.2024.101452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 12/22/2024] [Accepted: 12/22/2024] [Indexed: 01/01/2025]
Abstract
Diarrhea associated with enteric infections, gut inflammation, and genetic defects poses a major health burden and results in significant morbidity and mortality. Impaired fluid and electrolyte absorption or secretion in the intestine are the hallmark of diarrhea. Electroneutral NaCl absorption in the mammalian GI tract involves the coupling of Na+/H+ and Cl-/HCO3- exchangers. SLC26A3 (Down Regulated in Adenoma, DRA) is the major anion exchanger involved in luminal Cl- absorption and HCO3- secretion. Mutations in the SLC26A3 gene cause a severe disease called congenital chloride diarrhea (CLD). Multiple studies have shown that DRA function or expression is downregulated in infectious diarrheal disorders caused by EPEC, C rodentium, Salmonella, Clostridioides difficile and Cryptosporidium parvum infection. In addition, DRA levels are severely depleted in colonic mucosa of IBD patients and in mouse models of IBD (eg, DSS, TNBS, adoptive T-cell transfer, anti-CD-40, and IL-10 KO colitis). In addition, genetic defects exhibiting diarrhea including microvillus inclusion disease (MVID), keratin-8 depletion, knock-out mouse models of transcriptional factors (eg, CDX-2 and HNF1α/1β) also exhibit severe down regulation of DRA. Also, recent studies have shown that DRA is not only critical for chloride absorption but also plays a key role in maintaining gut epithelial barrier integrity, microbiome composition, and has now emerged as an IBD susceptibility gene. In this review, we provide strong evidence that DRA may serve as a novel therapeutic target with dual benefits in not only correcting diarrheal phenotype but also improving gut barrier integrity and inflammation in pathogen infection or IBD.
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Affiliation(s)
- Anoop Kumar
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois Chicago, Chicago, Illinois; Jesse Brown VA Medical Center, Chicago, Illinois
| | - Dulari Jayawardena
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois Chicago, Chicago, Illinois
| | - Shubha Priyamvada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois Chicago, Chicago, Illinois
| | - Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois Chicago, Chicago, Illinois
| | - Ishita Chatterjee
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois Chicago, Chicago, Illinois
| | - Seema Saksena
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois Chicago, Chicago, Illinois; Jesse Brown VA Medical Center, Chicago, Illinois
| | - Pradeep K Dudeja
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois Chicago, Chicago, Illinois; Jesse Brown VA Medical Center, Chicago, Illinois.
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Ouahed JD, Griffith A, Collen LV, Snapper SB. Breaking Down Barriers: Epithelial Contributors to Monogenic IBD Pathogenesis. Inflamm Bowel Dis 2024; 30:1189-1206. [PMID: 38280053 PMCID: PMC11519031 DOI: 10.1093/ibd/izad319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Indexed: 01/29/2024]
Abstract
Monogenic causes of inflammatory bowel diseases (IBD) are increasingly being discovered. To date, much attention has been placed in those resulting from inborn errors of immunity. Therapeutic efforts have been largely focused on offering personalized immune modulation or curative bone marrow transplant for patients with IBD and underlying immune disorders. To date, less emphasis has been placed on monogenic causes of IBD that pertain to impairment of the intestinal epithelial barrier. Here, we provide a comprehensive review of monogenic causes of IBD that result in impaired intestinal epithelial barrier that are categorized into 6 important functions: (1) epithelial cell organization, (2) epithelial cell intrinsic functions, (3) epithelial cell apoptosis and necroptosis, (4) complement activation, (5) epithelial cell signaling, and (6) control of RNA degradation products. We illustrate how impairment of any of these categories can result in IBD. This work reviews the current understanding of the genes involved in maintaining the intestinal barrier, the inheritance patterns that result in dysfunction, features of IBD resulting from these disorders, and pertinent translational work in this field.
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Affiliation(s)
- Jodie D Ouahed
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Alexandra Griffith
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Lauren V Collen
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Scott B Snapper
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
- Division of Gastroenterology, Department of Medicine, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA, USA
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Dominguez Rieg JA, Rieg T. New functions and roles of the Na +-H +-exchanger NHE3. Pflugers Arch 2024; 476:505-516. [PMID: 38448727 DOI: 10.1007/s00424-024-02938-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 02/22/2024] [Accepted: 02/27/2024] [Indexed: 03/08/2024]
Abstract
The sodium/proton exchanger isoform 3 (NHE3) is expressed in the intestine and the kidney, where it contributes to hydrogen secretion and sodium (re)absorption. The roles of this transporter have been studied by the use of the respective knockout mice and by using pharmacological inhibitors. Whole-body NHE3 knockout mice suffer from a high mortality rate (with only ∼30% of mice surviving into adulthood), and based on the expression of NHE3 in both intestine and kidney, some conclusions that were originally derived were based on this rather complex phenotype. In the last decade, more refined models have been developed that added temporal and spatial control of NHE3 expression. For example, novel mouse models have been developed with a knockout of NHE3 in intestinal epithelial cells, tubule/collecting duct of the kidney, proximal tubule of the kidney, and thick ascending limb of the kidney. These refined models have significantly contributed to our understanding of the role of NHE3 in a tissue/cell type-specific manner. In addition, tenapanor was developed, which is a non-absorbable, intestine-specific NHE3 inhibitor. In rat and human studies, tenapanor lowered intestinal Pi uptake and was effective in lowering plasma Pi levels in patients on hemodialysis. Of note, diarrhea is seen as a side effect of tenapanor (with its indication for the treatment of constipation) and in intestine-specific NHE3 knockout mice; however, effects on plasma Pi were not supported by this mouse model which showed enhanced and not reduced intestinal Pi uptake. Further studies indicated that the gut microbiome in mice lacking intestinal NHE3 resembles an intestinal environment favoring the competitive advantage of inflammophilic over anti-inflammatory species, something similar seen in patients with inflammatory bowel disease. This review will highlight recent developments and summarize newly gained insight from these refined models.
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Affiliation(s)
- Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
- James A. Haley Veterans' Hospital, Tampa, FL, 33612, USA
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, 33602, USA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.
- James A. Haley Veterans' Hospital, Tampa, FL, 33612, USA.
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, 33602, USA.
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Peritore-Galve FC, Kaji I, Smith A, Walker LM, Shupe JA, Washington MK, Algood HMS, Dudeja PK, Goldenring JR, Lacy DB. Increased intestinal permeability and downregulation of absorptive ion transporters Nhe3, Dra, and Sglt1 contribute to diarrhea during Clostridioides difficile infection. Gut Microbes 2023; 15:2225841. [PMID: 37350393 PMCID: PMC10291935 DOI: 10.1080/19490976.2023.2225841] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 06/09/2023] [Indexed: 06/24/2023] Open
Abstract
BACKGROUND & AIM Clostridioides difficile infection (CDI) is the leading cause of hospital-acquired diarrhea and pseudomembranous colitis. Two protein toxins, TcdA and TcdB, produced by C. difficile are the major determinants of disease. However, the pathophysiological causes of diarrhea during CDI are not well understood. Here, we investigated the effects of C. difficile toxins on paracellular permeability and apical ion transporters in the context of an acute physiological infection. METHODS We studied intestinal permeability and apical membrane transporters in female C57BL/6J mice. Üssing chambers were used to measure paracellular permeability and ion transporter function across the intestinal tract. Infected intestinal tissues were analyzed by immunofluorescence microscopy and RNA-sequencing to uncover mechanisms of transporter dysregulation. RESULTS Intestinal permeability was increased through the size-selective leak pathway in vivo during acute CDI in a 2-day-post infection model. Chloride secretory activity was reduced in the cecum and distal colon during infection by decreased CaCC and CFTR function, respectively. SGLT1 activity was significantly reduced in the cecum and colon, accompanied by ablated SGLT1 expression in colonocytes and increased luminal glucose concentrations. SGLT1 and DRA expression was ablated by either TcdA or TcdB during acute infection, but NHE3 was decreased in a TcdB-dependent manner. The localization of key proteins that link filamentous actin to the ion transporters in the apical plasma membrane was unchanged. However, Sglt1, Nhe3, and Dra were drastically reduced at the transcript level, implicating downregulation of ion transporters in the mechanism of diarrhea during CDI. CONCLUSIONS CDI increases intestinal permeability and decreases apical abundance of NHE3, SGLT1, and DRA. This combination likely leads to dysfunctional water and solute absorption in the large bowel, causing osmotic diarrhea. These findings provide insights into the pathophysiological mechanisms underlying diarrhea and may open novel avenues for attenuating CDI-associated diarrhea.
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Affiliation(s)
- F. Christopher Peritore-Galve
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Izumi Kaji
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Anna Smith
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lauren M. Walker
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John A. Shupe
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - M. Kay Washington
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Holly M. Scott Algood
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Pradeep K. Dudeja
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Veterans Affairs, Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
| | - James R. Goldenring
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
- Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - D. Borden Lacy
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
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Hammers DE, Donahue DL, Tucker Z, Ashfeld BL, Ploplis VA, Castellino FJ, Lee SW. Streptolysin S targets the sodium-bicarbonate cotransporter NBCn1 to induce inflammation and cytotoxicity in human keratinocytes during Group A Streptococcal infection. Front Cell Infect Microbiol 2022; 12:1002230. [PMID: 36389147 PMCID: PMC9663810 DOI: 10.3389/fcimb.2022.1002230] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 09/29/2022] [Indexed: 11/30/2022] Open
Abstract
Group A <i>Streptococcus</i> (GAS, <i>Streptococcus pyogenes</i>) is a Gram-positive human pathogen that employs several secreted and surface-bound virulence factors to manipulate its environment, allowing it to cause a variety of disease outcomes. One such virulence factor is Streptolysin S (SLS), a ribosomally-produced peptide toxin that undergoes extensive post-translational modifications. The activity of SLS has been studied for over 100 years owing to its rapid and potent ability to lyse red blood cells, and the toxin has been shown to play a major role in GAS virulence <i>in vivo</i>. We have previously demonstrated that SLS induces hemolysis by targeting the chloride-bicarbonate exchanger Band 3 in erythrocytes, indicating that SLS is capable of targeting host proteins to promote cell lysis. However, the possibility that SLS has additional protein targets in other cell types, such as keratinocytes, has not been explored. Here, we use bioinformatics analysis and chemical inhibition studies to demonstrate that SLS targets the electroneutral sodium-bicarbonate cotransporter NBCn1 in keratinocytes during GAS infection. SLS induces NF-κB activation and host cytotoxicity in human keratinocytes, and these processes can be mitigated by treating keratinocytes with the sodium-bicarbonate cotransport inhibitor S0859. Furthermore, treating keratinocytes with SLS disrupts the ability of host cells to regulate their intracellular pH, and this can be monitored in real time using the pH-sensitive dye pHrodo Red AM in live imaging studies. These results demonstrate that SLS is a multifunctional bacterial toxin that GAS uses in numerous context-dependent ways to promote host cell cytotoxicity and increase disease severity. Studies to elucidate additional host targets of SLS have the potential to impact the development of therapeutics for severe GAS infections.
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Affiliation(s)
- Daniel E. Hammers
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States,Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States
| | - Deborah L. Donahue
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States,William Myron (W. M.) Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States
| | - Zachary D. Tucker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
| | - Brandon L. Ashfeld
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
| | - Victoria A. Ploplis
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States,William Myron (W. M.) Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States
| | - Francis J. Castellino
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States,William Myron (W. M.) Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States
| | - Shaun W. Lee
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States,Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States,William Myron (W. M.) Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States,*Correspondence: Shaun W. Lee,
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Xue J, Dominguez Rieg JA, Thomas L, White JR, Rieg T. Intestine-Specific NHE3 Deletion in Adulthood Causes Microbial Dysbiosis. Front Cell Infect Microbiol 2022; 12:896309. [PMID: 35719363 PMCID: PMC9204535 DOI: 10.3389/fcimb.2022.896309] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/21/2022] [Indexed: 11/13/2022] Open
Abstract
In the intestine, the Na+/H+ exchanger 3 (NHE3) plays a critical role for Na+ and fluid absorption. NHE3 deficiency predisposes patients to inflammatory bowel disease (IBD). In mice, selective deletion of intestinal NHE3 causes various local and systemic pathologies due to dramatic changes in the intestinal environment, which can influence microbiota colonization. By using metagenome shotgun sequencing, we determined the effect of inducible intestinal epithelial cell-specific deletion of NHE3 (NHE3IEC-KO) in adulthood on the gut microbiome in mice. Compared with control mice, NHE3IEC-KO mice show a significantly different gut microbiome signature, with an unexpected greater diversity. At the phylum level, NHE3IEC-KO mice showed a significant expansion in Proteobacteria and a tendency for lower Firmicutes/Bacteroidetes (F/B) ratio, an indicator of dysbiosis. At the family level, NHE3IEC-KO mice showed significant expansions in Bacteroidaceae, Rikenellaceae, Tannerellaceae, Flavobacteriaceae and Erysipelotrichaceae, but had contractions in Lachnospiraceae, Prevotellaceae and Eubacteriaceae. At the species level, after removing those with lowest occurrence and abundance, we identified 23 species that were significantly expanded (several of which are established pro-inflammatory pathobionts); whereas another 23 species were found to be contracted (some of which are potential anti-inflammatory probiotics) in NHE3IEC-KO mice. These results reveal that intestinal NHE3 deletion creates an intestinal environment favoring the competitive advantage of inflammophilic over anti-inflammatory species, which is commonly featured in conventional NHE3 knockout mice and patients with IBD. In conclusion, our study emphasizes the importance of intestinal NHE3 for gut microbiota homeostasis, and provides a deeper understanding regarding interactions between NHE3, dysbiosis, and IBD.
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Affiliation(s)
- Jianxiang Xue
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, United States
| | - Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, United States.,James A. Haley Veterans' Hospital, Tampa, FL, United States
| | - Linto Thomas
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, United States
| | - James R White
- Resphera Biosciences LLC, Baltimore, MD, United States
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, United States.,James A. Haley Veterans' Hospital, Tampa, FL, United States.,Center for Hypertension and Kidney Research, University of South Florida, Tampa, FL, United States
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Nikolovska K, Seidler UE, Stock C. The Role of Plasma Membrane Sodium/Hydrogen Exchangers in Gastrointestinal Functions: Proliferation and Differentiation, Fluid/Electrolyte Transport and Barrier Integrity. Front Physiol 2022; 13:899286. [PMID: 35665228 PMCID: PMC9159811 DOI: 10.3389/fphys.2022.899286] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 04/19/2022] [Indexed: 12/11/2022] Open
Abstract
The five plasma membrane Na+/H+ exchanger (NHE) isoforms in the gastrointestinal tract are characterized by distinct cellular localization, tissue distribution, inhibitor sensitivities, and physiological regulation. NHE1 (Slc9a1) is ubiquitously expressed along the gastrointestinal tract in the basolateral membrane of enterocytes, but so far, an exclusive role for NHE1 in enterocyte physiology has remained elusive. NHE2 (Slc9a2) and NHE8 (Slc9a8) are apically expressed isoforms with ubiquitous distribution along the colonic crypt axis. They are involved in pHi regulation of intestinal epithelial cells. Combined use of a knockout mouse model, intestinal organoid technology, and specific inhibitors revealed previously unrecognized actions of NHE2 and NHE8 in enterocyte proliferation and differentiation. NHE3 (Slc9a3), expressed in the apical membrane of differentiated intestinal epithelial cells, functions as the predominant nutrient-independent Na+ absorptive mechanism in the gut. The new selective NHE3 inhibitor (Tenapanor) allowed discovery of novel pathophysiological and drug-targetable NHE3 functions in cystic-fibrosis associated intestinal obstructions. NHE4, expressed in the basolateral membrane of parietal cells, is essential for parietal cell integrity and acid secretory function, through its role in cell volume regulation. This review focuses on the expression, regulation and activity of the five plasma membrane Na+/H+ exchangers in the gastrointestinal tract, emphasizing their role in maintaining intestinal homeostasis, or their impact on disease pathogenesis. We point to major open questions in identifying NHE interacting partners in central cellular pathways and processes and the necessity of determining their physiological role in a system where their endogenous expression/activity is maintained, such as organoids derived from different parts of the gastrointestinal tract.
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Arostegui D, Wallach T. The Cutting Edge of Gastroenteritis: Advances in Understanding of Enteric Infection. J Pediatr Gastroenterol Nutr 2022; 74:180-185. [PMID: 34560728 DOI: 10.1097/mpg.0000000000003304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
ABSTRACT In recent years, multiple advances have been made in the care, diagnosis, and mechanistic understanding of acute gastroenteritis (AGE). In this review, we discuss the current state of the art of diagnosis and management, as well as how changes in practice can improve care and decrease costs. We will discuss present study demonstrating the effect of AGE on the microbiome and how that may be linked to secondary effects or long-term changes. We will explore the use of novel technologies to further our capacity to understand how gastrointestinal infections occur and promulgate. Finally, will discuss advances in our understanding of how gastrointestinal infections capacitate other changes such as post-viral motility or other post viral intestinal dysfunction.
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Affiliation(s)
- Dalia Arostegui
- SUNY Downstate Department of Pediatrics, Division of Pediatric Gastroenterology, Brooklyn, NY
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Steichen C, Hervé C, Hauet T, Bourmeyster N. Rho GTPases in kidney physiology and diseases. Small GTPases 2022; 13:141-161. [PMID: 34138686 PMCID: PMC9707548 DOI: 10.1080/21541248.2021.1932402] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 05/08/2021] [Accepted: 05/17/2021] [Indexed: 02/06/2023] Open
Abstract
Rho family GTPases are molecular switches best known for their pivotal role in dynamic regulation of the actin cytoskeleton, but also of cellular morphology, motility, adhesion and proliferation. The prototypic members of this family (RhoA, Rac1 and Cdc42) also contribute to the normal kidney function and play important roles in the structure and function of various kidney cells including tubular epithelial cells, mesangial cells and podocytes. The kidney's vital filtration function depends on the structural integrity of the glomerulus, the proximal portion of the nephron. Within the glomerulus, the architecturally actin-based cytoskeleton podocyte forms the final cellular barrier to filtration. The glomerulus appears as a highly dynamic signalling hub that is capable of integrating intracellular cues from its individual structural components. Dynamic regulation of the podocyte cytoskeleton is required for efficient barrier function of the kidney. As master regulators of actin cytoskeletal dynamics, Rho GTPases are therefore of critical importance for sustained kidney barrier function. Dysregulated activities of the Rho GTPases and of their effectors are implicated in the pathogenesis of both hereditary and idiopathic forms of kidney diseases. Diabetic nephropathy is a progressive kidney disease that is caused by injury to kidney glomeruli. High glucose activates RhoA/Rho-kinase in mesangial cells, leading to excessive extracellular matrix production (glomerulosclerosis). This RhoA/Rho-kinase pathway also seems involved in the post-transplant hypertension frequently observed during treatment with calcineurin inhibitors, whereas Rac1 activation was observed in post-transplant ischaemic acute kidney injury.
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Affiliation(s)
- Clara Steichen
- Inserm UMR-1082 Irtomit, Poitiers, France
- Faculté De Médecine Et De Pharmacie, Université De Poitiers, Poitiers, France
| | | | - Thierry Hauet
- Inserm UMR-1082 Irtomit, Poitiers, France
- Faculté De Médecine Et De Pharmacie, Université De Poitiers, Poitiers, France
- Department of Medical Biology, Service De Biochimie, CHU De Poitiers, Poitiers, France
| | - Nicolas Bourmeyster
- Faculté De Médecine Et De Pharmacie, Université De Poitiers, Poitiers, France
- Department of Medical Biology, Service De Biochimie, CHU De Poitiers, Poitiers, France
- Laboratoire STIM CNRS ERL 7003, Université de Poitiers, Poitiers Cédex, France
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Monaghan TM, Seekatz AM, Mullish BH, Moore-Gillon CCER, Dawson LF, Ahmed A, Kao D, Chan WC. Clostridioides difficile: innovations in target discovery and potential for therapeutic success. Expert Opin Ther Targets 2021; 25:949-963. [PMID: 34793686 DOI: 10.1080/14728222.2021.2008907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/17/2021] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Clostridioides difficile infection (CDI) remains a worldwide clinical problem. Increased incidence of primary infection, occurrence of hypertoxigenic ribotypes, and more frequent occurrence of drug resistant, recurrent, and non-hospital CDI, emphasizes the urgent unmet need of discovering new therapeutic targets. AREAS COVERED We searched PubMed and Web of Science databases for articles identifying novel therapeutic targets or treatments for C. difficile from 2001 to 2021. We present an updated review on current preclinical efforts on designing inhibitory compounds against these drug targets and indicate how these could become the focus of future therapeutic approaches. We also evaluate the increasing exploitability of gut microbial-derived metabolites and host-derived therapeutics targeting VEGF-A, immune targets and pathways, ion transporters, and microRNAs as anti-C. difficile therapeutics, which have yet to reach clinical trials. Our review also highlights the therapeutic potential of re-purposing currently available agents . We conclude by considering translational hurdles and possible strategies to mitigate these problems. EXPERT OPINION Considerable progress has been made in the development of new anti-CDI drug candidates. Nevertheless, a greater comprehension of CDI pathogenesis and host-microbe interactions is beginning to uncover potential novel therapeutic targets, which can be exploited to plug gaps in the CDI drug discovery pipeline.
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Affiliation(s)
- Tanya M Monaghan
- NIHR Nottingham Biomedical Research Centre, University of Nottingham, Nottingham, UK
- Nottingham Digestive Diseases Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Anna M Seekatz
- Biological Sciences, Clemson University, Clemson, SC, USA
| | - Benjamin H Mullish
- Division of Digestive Diseases, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK
- Departments of Gastroenterology and Hepatology, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - Claudia C E R Moore-Gillon
- Division of Digestive Diseases, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK
- Departments of Gastroenterology and Hepatology, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - Lisa F Dawson
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Ammar Ahmed
- NIHR Nottingham Biomedical Research Centre, University of Nottingham, Nottingham, UK
- Nottingham Digestive Diseases Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Dina Kao
- Department of Gastroenterology, Zeidler Ledcor Centre, University of Alberta, Edmonton, Alberta, Canada
| | - Weng C Chan
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, University Park, Nottingham, UK
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Quade BN, Parker MD, Occhipinti R. The therapeutic importance of acid-base balance. Biochem Pharmacol 2021; 183:114278. [PMID: 33039418 PMCID: PMC7544731 DOI: 10.1016/j.bcp.2020.114278] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/06/2020] [Indexed: 02/06/2023]
Abstract
Baking soda and vinegar have been used as home remedies for generations and today we are only a mouse-click away from claims that baking soda, lemon juice, and apple cider vinegar are miracles cures for everything from cancer to COVID-19. Despite these specious claims, the therapeutic value of controlling acid-base balance is indisputable and is the basis of Food and Drug Administration-approved treatments for constipation, epilepsy, metabolic acidosis, and peptic ulcers. In this narrative review, we present evidence in support of the current and potential therapeutic value of countering local and systemic acid-base imbalances, several of which do in fact involve the administration of baking soda (sodium bicarbonate). Furthermore, we discuss the side effects of pharmaceuticals on acid-base balance as well as the influence of acid-base status on the pharmacokinetic properties of drugs. Our review considers all major organ systems as well as information relevant to several clinical specialties such as anesthesiology, infectious disease, oncology, dentistry, and surgery.
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Affiliation(s)
- Bianca N Quade
- Department of Physiology and Biophysics, The State University of New York, The University at Buffalo, Buffalo, NY 14203, USA
| | - Mark D Parker
- Department of Physiology and Biophysics, The State University of New York, The University at Buffalo, Buffalo, NY 14203, USA; Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA; State University of New York Eye Institute, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Rossana Occhipinti
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA.
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12
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Ranganathan S, Smith EM, Foulke-Abel JD, Barry EM. Research in a time of enteroids and organoids: how the human gut model has transformed the study of enteric bacterial pathogens. Gut Microbes 2020; 12:1795492. [PMID: 32795243 PMCID: PMC7524385 DOI: 10.1080/19490976.2020.1795389] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/29/2020] [Accepted: 07/01/2020] [Indexed: 02/03/2023] Open
Abstract
Enteric bacterial pathogens cause significant morbidity and mortality globally. Studies in tissue culture and animal models shaped our initial understanding of these host-pathogen interactions. However, intrinsic shortcomings in these models limit their application, especially in translational applications like drug screening and vaccine development. Human intestinal enteroid and organoid models overcome some limitations of existing models and advance the study of enteric pathogens. In this review, we detail the use of human enteroids and organoids to investigate the pathogenesis of invasive bacteria Shigella, Listeria, and Salmonella, and noninvasive bacteria pathogenic Escherichia coli, Clostridium difficile, and Vibrio cholerae. We highlight how these studies confirm previously identified mechanisms and, importantly, reveal novel ones. We also discuss the challenges for model advancement, including platform engineering to integrate environmental conditions, innate immune cells and the resident microbiome, and the potential for pre-clinical testing of recently developed antimicrobial drugs and vaccines.
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Affiliation(s)
- Sridevi Ranganathan
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Emily M. Smith
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jennifer D. Foulke-Abel
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Eileen M. Barry
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
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13
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Cao L, Yuan Z, Liu M, Stock C. (Patho-)Physiology of Na +/H + Exchangers (NHEs) in the Digestive System. Front Physiol 2020; 10:1566. [PMID: 32009977 PMCID: PMC6974801 DOI: 10.3389/fphys.2019.01566] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 12/12/2019] [Indexed: 02/06/2023] Open
Abstract
Na+/H+ exchangers (NHEs) are expressed in virtually all human tissues and organs. Two major tasks of those NHE isoforms that are located in plasma membranes are cell volume control by Na+-uptake and cellular pH regulation by H+-extrusion. Several NHEs, particularly NHE 1–4 and 8, are involved in the pathogenesis of diseases of the digestive system such as inflammatory bowel disease (ulcerative colitis, Crohn’s disease) and gastric and colorectal tumorigenesis. In the present review, we describe the physiological purposes, possible malfunctions and pathophysiological effects of the different NHE isoforms along the alimentary canal from esophagus to colon, including pancreas, liver and gallbladder. Particular attention is paid to the functions of NHEs in injury repair and to the role of NHE1 in Barrett’s esophagus. The impact of NHEs on gut microbiota and intestinal mucosal integrity is also dealt with. As the hitherto existing findings are not always consistent, sometimes even controversial, they are compared and critically discussed.
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Affiliation(s)
- Li Cao
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhenglin Yuan
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Mei Liu
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Christian Stock
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hanover, Germany
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14
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Yanda MK, Cha B, Cebotaru CV, Cebotaru L. Pharmacological reversal of renal cysts from secretion to absorption suggests a potential therapeutic strategy for managing autosomal dominant polycystic kidney disease. J Biol Chem 2019; 294:17090-17104. [PMID: 31570523 DOI: 10.1074/jbc.ra119.010320] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/26/2019] [Indexed: 12/19/2022] Open
Abstract
Autosomal-dominant polycystic kidney disease (ADPKD) induces a secretory phenotype, resulting in multiple fluid-filled cysts. We have previously demonstrated that VX-809, a corrector of the cystic fibrosis transmembrane conductance regulator (CFTR), reduces cyst growth. Here, we show that in normal mice CFTR is located within the cells and also at the apical and basolateral membranes. However, in polycystic kidney disease (pkd1)-knockout mice, CFTR was located at the plasma membrane, consistent with its role in cAMP-dependent fluid secretion. In cystic mice, VX-809 treatment increased CFTR levels at the apical membrane and reduced its association with the endoplasmic reticulum. Surprisingly, VX-809 treatment significantly increased CFTR's co-localization with the basolateral membrane in cystic mice. Na+/H+ exchanger 3 (NHE3) is present in pkd1-knockout and normal mice and in proximal tubule-derived, cultured pkd1-knockout cells. VX-809 increased the expression, activity, and apical plasma membrane localization of NHE3. Co-localization of epithelial sodium channel (ENaC) with the plasma membrane was reduced in cysts in pkd1-knockout mice, consistent with an inability of the cysts to absorb fluid. Interestingly, in the cystic mice, VX-809 treatment increased ENaC levels at the apical plasma membrane consistent with fluid absorption. Thus, VX-809 treatment of pkd1-null mouse kidneys significantly affected CFTR, NHE3, and ENaC, altering the cyst phenotype from one poised toward fluid secretion toward one more favorable for absorption. VX-809 also altered the location of CFTR but not of NHE3 or ENaC in normal mice. Given that VX-809 administration is safe, it may have potential utility for treating patients with ADPKD.
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Affiliation(s)
- Murali K Yanda
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Boyoung Cha
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Cristina V Cebotaru
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Liudmila Cebotaru
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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15
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Dee RA, Mangum KD, Bai X, Mack CP, Taylor JM. Druggable targets in the Rho pathway and their promise for therapeutic control of blood pressure. Pharmacol Ther 2019; 193:121-134. [PMID: 30189292 PMCID: PMC7235948 DOI: 10.1016/j.pharmthera.2018.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The prevalence of high blood pressure (also known as hypertension) has steadily increased over the last few decades. Known as a silent killer, hypertension increases the risk for cardiovascular disease and can lead to stroke, heart attack, kidney failure and associated sequela. While numerous hypertensive therapies are currently available, it is estimated that only half of medicated patients exhibit blood pressure control. This signifies the need for a better understanding of the underlying cause of disease and for more effective therapies. While blood pressure homeostasis is very complex and involves the integrated control of multiple body systems, smooth muscle contractility and arterial resistance are important contributors. Strong evidence from pre-clinical animal models and genome-wide association studies indicate that smooth muscle contraction and BP homeostasis are governed by the small GTPase RhoA and its downstream target, Rho kinase. In this review, we summarize the signaling pathways and regulators that impart tight spatial-temporal control of RhoA activity in smooth muscle cells and discuss current therapeutic strategies to target these RhoA pathway components. We also discuss known allelic variations in the RhoA pathway and consider how these polymorphisms may affect genetic risk for hypertension and its clinical manifestations.
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Affiliation(s)
- Rachel A Dee
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kevin D Mangum
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Xue Bai
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Christopher P Mack
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Joan M Taylor
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA.
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16
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Harrison CA, Laubitz D, Ohland CL, Midura-Kiela MT, Patil K, Besselsen DG, Jamwal DR, Jobin C, Ghishan FK, Kiela PR. Microbial dysbiosis associated with impaired intestinal Na +/H + exchange accelerates and exacerbates colitis in ex-germ free mice. Mucosal Immunol 2018; 11:1329-1341. [PMID: 29875400 PMCID: PMC6162102 DOI: 10.1038/s41385-018-0035-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 03/29/2018] [Accepted: 04/15/2018] [Indexed: 02/04/2023]
Abstract
Intestinal epithelial Na+/H+ exchange facilitated by the apical NHE3 (Slc9a3) is a highly regulated process inhibited by intestinal pathogens and in inflammatory bowel diseases. NHE3-/- mice develop spontaneous, bacterially mediated colitis, and IBD-like dysbiosis. Disruption of epithelial Na+/H+ exchange in IBD may thus represent a host response contributing to the altered gut microbial ecology, and may play a pivotal role in modulating the severity of inflammation in a microbiome-dependent manner. To test whether microbiome fostered in an NHE3-deficient environment is able to drive mucosal immune responses affecting the onset or severity of colitis, we performed a series of cohousing experiments and fecal microbiome transplants into germ-free Rag-deficient or IL-10-/- mice. We determined that in the settings where the microbiome of NHE3-deficient mice was stably engrafted in the recipient host, it was able accelerate the onset and amplify severity of experimental colitis. NHE3-deficiency was characterized by the reduction in pH-sensitive butyrate-producing Firmicutes families Lachnospiraceae and Ruminococcaceae (Clostridia clusters IV and XIVa), with an expansion of inflammation-associated Bacteroidaceae. We conclude that the microbiome fostered by impaired epithelial Na+/H+ exchange enhances the onset and severity of colitis through disruption of the gut microbial ecology.
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Affiliation(s)
- Christy A Harrison
- Department of Pediatrics, Steele Children's Research Center, Tucson, AZ, USA
- Department of Immunobiology, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Daniel Laubitz
- Department of Pediatrics, Steele Children's Research Center, Tucson, AZ, USA
| | | | | | - Karuna Patil
- University Animal Care, University of Arizona, Tucson, AZ, USA
| | | | - Deepa R Jamwal
- Department of Pediatrics, Steele Children's Research Center, Tucson, AZ, USA
| | - Christian Jobin
- Division of Gastroenterology, Department of Medicine, University of Florida College of Medicine, Gainesville, FL, USA
| | - Fayez K Ghishan
- Department of Pediatrics, Steele Children's Research Center, Tucson, AZ, USA
| | - Pawel R Kiela
- Department of Pediatrics, Steele Children's Research Center, Tucson, AZ, USA.
- Department of Immunobiology, University of Arizona College of Medicine, Tucson, AZ, USA.
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17
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Urdaci MC, Lefevre M, Lafforgue G, Cartier C, Rodriguez B, Fioramonti J. Antidiarrheal Action of Bacillus subtilis CU1 CNCM I-2745 and Lactobacillus plantarum CNCM I-4547 in Mice. Front Microbiol 2018; 9:1537. [PMID: 30042756 PMCID: PMC6048234 DOI: 10.3389/fmicb.2018.01537] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/20/2018] [Indexed: 12/29/2022] Open
Abstract
Preventive actions of probiotics as antidiarrheal agents are well documented, but their mechanisms are poorly understood. Two selected probiotics, Bacillus subtilis CU1 and Lactobacillus plantarum CNCM I-4547, were tested in mouse experimental models of diarrhea and the possible mechanisms of action were investigated. Diarrhea was induced in mice by oral castor oil administration or by i.v. injection of lipopolysaccharide (LPS) of Salmonella enteritis. The antidiarrheal drug loperamide was used as control. Fecal water excretion was quantified for 2 h and paracellular permeability and electrical parameters of the colon were assessed in Ussing chambers. The expression of colonic exchangers or channels and of Toll-like receptor 4 (TLR4) was assessed by immunohistochemistry. Prophylactic treatment with B. subtilis CU1 or with L. plantarum CNCM I-4547 reduced LPS-induced diarrhea. The reduction of water excretion was in the same range as those induced by loperamide. In the castor oil model, this effect was only observed with B. subtilis CU1. The two probiotic treatments abolished the increase in paracellular permeability induced by LPS, but not by castor oil. However, only L. plantarum CNCM I-4547 treatment decreased the colonic expression of TLR-4. After B. subtilis CU1, colonic expression of cystic fibrosis transmembrane conductance regulator (CFTR) was reduced and that of Na+/H+ exchanger 3 (NHE3) increased. B. subtilis CU1 may increase the capacity of the colon to absorb excess of water in diarrheic conditions by acting on CFTR and NHE3 expression. The two probiotics strains showed an impact on diarrhea through limitation of water excretion that may involve paracellular permeability or electrolyte transport for L. plantarum CNCM I-4547 and B. subtilis CU1 respectively.
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Affiliation(s)
- Maria C Urdaci
- Microbiology Laboratory, UMR 5248, Bordeaux Sciences Agro, University of Bordeaux, Gradignan, France
| | - Marie Lefevre
- Lesaffre Human Care, Lesaffre Group, Marcq-en-Baroeul, France
| | - Guylene Lafforgue
- Neuro-Gastroenterology and Nutrition Unit, INRA, Toulouse, France.,Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Christel Cartier
- Neuro-Gastroenterology and Nutrition Unit, INRA, Toulouse, France.,Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
| | | | - Jean Fioramonti
- Neuro-Gastroenterology and Nutrition Unit, INRA, Toulouse, France.,Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
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18
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Coffing H, Priyamvada S, Anbazhagan AN, Salibay C, Engevik M, Versalovic J, Yacyshyn MB, Yacyshyn B, Tyagi S, Saksena S, Gill RK, Alrefai WA, Dudeja PK. Clostridium difficile toxins A and B decrease intestinal SLC26A3 protein expression. Am J Physiol Gastrointest Liver Physiol 2018; 315:G43-G52. [PMID: 29597352 PMCID: PMC6109705 DOI: 10.1152/ajpgi.00307.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 03/06/2018] [Accepted: 03/12/2018] [Indexed: 01/31/2023]
Abstract
Clostridium difficile infection (CDI) is the primary cause of nosocomial diarrhea in the United States. Although C. difficile toxins A and B are the primary mediators of CDI, the overall pathophysiology underlying C. difficile-associated diarrhea remains poorly understood. Studies have shown that a decrease in both NHE3 (Na+/H+ exchanger) and DRA (downregulated in adenoma, Cl-/[Formula: see text] exchanger), resulting in decreased electrolyte absorption, is implicated in infectious and inflammatory diarrhea. Furthermore, studies have shown that NHE3 is depleted at the apical surface of intestinal epithelial cells and downregulated in patients with CDI, but the role of DRA in CDI remains unknown. In the current studies, we examined the effects of C. difficile toxins TcdA and TcdB on DRA protein and mRNA levels in intestinal epithelial cells (IECs). Our data demonstrated that DRA protein levels were significantly reduced in response to TcdA and TcdB in IECs in culture. This effect was also specific to DRA, as NHE3 and PAT-1 (putative anion transporter 1) protein levels were unaffected by TcdA and TcdB. Additionally, purified TcdA and TcdA + TcdB, but not TcdB, resulted in a decrease in colonic DRA protein levels in a toxigenic mouse model of CDI. Finally, patients with recurrent CDI also exhibited significantly reduced expression of colonic DRA protein. Together, these findings indicate that C. difficile toxins markedly downregulate intestinal expression of DRA which may contribute to the diarrheal phenotype of CDI. NEW & NOTEWORTHY Our studies demonstrate, for the first time, that C. difficile toxins reduce DRA protein, but not mRNA, levels in intestinal epithelial cells. These findings suggest that a downregulation of DRA may be a critical factor in C. difficile infection-associated diarrhea.
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Affiliation(s)
- Hayley Coffing
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Shubha Priyamvada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Christine Salibay
- Department of Pathology, University of Illinois at Chicago , Chicago, Illinois
| | - Melinda Engevik
- Department of Pathology and Immunology, Baylor College of Medicine and Department of Pathology, Texas Children's Hospital , Houston, Texas
| | - James Versalovic
- Department of Pathology and Immunology, Baylor College of Medicine and Department of Pathology, Texas Children's Hospital , Houston, Texas
| | - Mary Beth Yacyshyn
- Division of Digestive Diseases, Department. of Medicine, University of Cincinnati College of Medicine , Cincinnati, Ohio
| | - Bruce Yacyshyn
- Division of Digestive Diseases, Department. of Medicine, University of Cincinnati College of Medicine , Cincinnati, Ohio
| | - Sangeeta Tyagi
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Seema Saksena
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| | - Ravinder K Gill
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Waddah A Alrefai
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| | - Pradeep K Dudeja
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
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19
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Abstract
The gut has great importance for the commercial success of poultry production. Numerous ion transporters, exchangers, and channels are present on both the apical and the basolateral membrane of intestinal epithelial cells, and their differential expression along the crypt-villus axis within the various intestinal segments ensures efficient intestinal absorption and effective barrier function. Recent studies have shown that intensive production systems, microbial exposure, and nutritional management significantly affect intestinal physiology and intestinal ion transport. Dysregulation of normal intestinal ion transport is manifested as diarrhoea, malabsorption, and intestinal inflammation resulting into poor production efficiency. This review discusses the basic mechanisms involved in avian intestinal ion transport and the impact of development during growth, nutritional and environmental alterations, and intestinal microbial infections on it. The effect of intestinal microbial infections on avian intestinal ion transport depends on factors such as host immunity, pathogen virulence, and the mucosal organisation of the particular intestinal segment.
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20
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Das S, Jayaratne R, Barrett KE. The Role of Ion Transporters in the Pathophysiology of Infectious Diarrhea. Cell Mol Gastroenterol Hepatol 2018; 6:33-45. [PMID: 29928670 PMCID: PMC6007821 DOI: 10.1016/j.jcmgh.2018.02.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 02/26/2018] [Indexed: 12/12/2022]
Abstract
Every year, enteric infections and associated diarrhea kill millions of people. The situation is compounded by increases in the number of enteric pathogens that are acquiring resistance to antibiotics, as well as (hitherto) a relative paucity of information on host molecular targets that may contribute to diarrhea. Many forms of diarrheal disease depend on the dysregulation of intestinal ion transporters, and an associated imbalance between secretory and absorptive functions of the intestinal epithelium. A number of major transporters have been implicated in the pathogenesis of diarrheal diseases and thus an understanding of their expression, localization, and regulation after infection with various bacteria, viruses, and protozoa likely will prove critical in designing new therapies. This article surveys our understanding of transporters that are modulated by specific pathogens and the mechanism(s) involved, thereby illuminating targets that might be exploited for new therapeutic approaches.
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Key Words
- ATP, adenosine triphosphate
- ATPase, adenosine triphosphatase
- CDI, Clostridium difficile infection
- CFTR, cystic fibrosis transmembrane conductance regulator
- CLCA1, chloride channel accessory 1
- CT, cholera toxin
- CXCR2, C-X-C motif chemokine receptor 2
- DRA, down-regulated in adenoma
- Diarrhea
- ENaC, epithelial sodium channel
- EPEC, enteropathogenic Escherichia coli
- ETEC, enterotoxigenic Escherichia coli
- Enteric Pathogen
- Epithelium
- EspG, Escherichia coli secreted protein G
- GPR39, G-protein coupled receptor 39
- Ion Transport
- KCC, potassium-chloride cotransporter
- LPA, lysophosphatidic acid
- LT, heat-labile toxin
- NHE, sodium/hydrogen exchanger
- NHERF2, sodium/hydrogen exchanger regulatory factor 2
- NKCC, sodium-potassium-2 chloride cotransporter
- ORT, oral rehydration therapy
- PKC, protein kinase C
- SGLT1, sodium-glucose cotransporter 1
- SLC, solute carrier
- ST, heat-stabile toxin
- TNF, tumor necrosis factor
- Tcd, Clostridium difficile toxin
- ZnR, zinc sensing receptor
- cAMP, adenosine 3′,5′-cyclic monophosphate
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Affiliation(s)
- Soumita Das
- Department of Pathology, University of California San Diego School of Medicine, La Jolla, California
| | - Rashini Jayaratne
- Department of Medicine, University of California San Diego School of Medicine, La Jolla, California
| | - Kim E. Barrett
- Department of Medicine, University of California San Diego School of Medicine, La Jolla, California,Correspondence Address correspondence to: Kim E. Barrett, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0063. fax: (858) 246-1788.
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21
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Roychowdhury S, Cadnum J, Glueck B, Obrenovich M, Donskey C, Cresci GAM. Faecalibacterium prausnitzii and a Prebiotic Protect Intestinal Health in a Mouse Model of Antibiotic and Clostridium difficile Exposure. JPEN J Parenter Enteral Nutr 2018; 42:1156-1167. [PMID: 29385239 DOI: 10.1002/jpen.1053] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/07/2017] [Accepted: 11/08/2017] [Indexed: 01/20/2023]
Abstract
BACKGROUND Clostridium difficile (CD) infection (CDI) increases patient morbidity, mortality and healthcare costs. Antibiotic treatment induces gut dysbiosis and is both a major risk factor for CD colonization and treatment of CDI. Probiotics have been trialed to support commensal gut microbiota and reduce CDI. This study investigated commensal microbe Faecalibacterium prausnitzii (FP) and a prebiotic, both known to yield butyrate and be anti-inflammatory and immunomodulatory, on CD colonization and gut integrity in mice. METHODS Mice were randomly grouped and supplemented daily with FP, prebiotic, FP + prebiotic, FP/prebiotic supernatant, or saline throughout the entire study. Following treatment with clindamycin for 3 days, mice were exposed to CD. Feces were collected at baseline, the day after antibiotic, and 1, 3, and 5 days after CD exposure and cultured for bacterial overgrowth and CD colonization. On days 1 and 5 after CD exposure, mice were randomly euthanized, and proximal colon was dissected for histological analysis and preparation of RNA for analysis of proinflammatory and anti-inflammatory cytokines. RESULTS Although all mice exhibited bacterial overgrowth and CD colonization, bacterial burden resolved quicker in the FP + prebiotic group. This was associated with induction and resolution of innate immune responses, anion exchanger, and tight junction protein preservation in proximal colon. CD toxin virulence potential was questionable as expression of CD toxin B receptor was depleted in the FP + prebiotic group. CONCLUSION Supplementation with anti-inflammatory butyrate-supporting commensal bacteria and prebiotic may support innate immune responses and minimize bacterial burden and negative effects during antibiotic and CD exposure.
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Affiliation(s)
- Sanjoy Roychowdhury
- Lerner Research Institute, Department of Pathobiology, Cleveland Clinic, Cleveland, Ohio, USA
| | - Jennifer Cadnum
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Bryan Glueck
- Lerner Research Institute, Department of Pathobiology, Cleveland Clinic, Cleveland, Ohio, USA
| | - Mark Obrenovich
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Curtis Donskey
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA.,Department of Medicine, Division of Infectious Diseases, Case Western Reserve University, Cleveland, Ohio, USA
| | - Gail A M Cresci
- Lerner Research Institute, Department of Pathobiology, Cleveland Clinic, Cleveland, Ohio, USA.,Pediatric Institute, Department of Gastroenterology, Cleveland Clinic, Cleveland, Ohio, USA.,Digestive Disease & Surgery Institute, Department of Gastroenterology & Hepatology, Cleveland Clinic, Cleveland, Ohio, USA
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22
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Yu H, Hasan NM, In JG, Estes MK, Kovbasnjuk O, Zachos NC, Donowitz M. The Contributions of Human Mini-Intestines to the Study of Intestinal Physiology and Pathophysiology. Annu Rev Physiol 2017; 79:291-312. [PMID: 28192061 PMCID: PMC5549102 DOI: 10.1146/annurev-physiol-021115-105211] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The lack of accessibility to normal and diseased human intestine and the inability to separate the different functional compartments of the intestine even when tissue could be obtained have held back the understanding of human intestinal physiology. Clevers and his associates identified intestinal stem cells and established conditions to grow "mini-intestines" ex vivo in differentiated and undifferentiated conditions. This pioneering work has made a new model of the human intestine available and has begun making contributions to the understanding of human intestinal transport in normal physiologic conditions and the pathophysiology of intestinal diseases. However, this model is reductionist and lacks many of the complexities of normal intestine. Consequently, it is not yet possible to predict how great the advances using this model will be for understanding human physiology and pathophysiology, nor how the model will be modified to include multiple other intestinal cell types and physical forces necessary to more closely approximate normal intestine. This review describes recent studies using mini-intestines, which have readdressed previously established models of normal intestinal transport physiology and newly examined intestinal pathophysiology. The emphasis is on studies with human enteroids grown either as three-dimensional spheroids or two-dimensional monolayers. In addition, comments are provided on mouse studies in cases when human studies have not yet been described.
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Affiliation(s)
- Huimin Yu
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Nesrin M Hasan
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Julie G In
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Mary K Estes
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | - Olga Kovbasnjuk
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Nicholas C Zachos
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Mark Donowitz
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
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23
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Abstract
The development of sustainable intestinal organoid cell culture has emerged as a new modality for the study of intestinal function and cellular processes. Organoid culture is providing a new testbed for therapeutic research and development. Intestinal organoids, self-renewing 3-dimensional structures comprised intestinal stem cells and their differentiated epithelial progeny allow for more facile and robust exploration of cellular activity, cell organization and structure, genetic manipulation, and vastly more physiologic modeling of intestinal response to stimuli as compared to traditional 2-dimensional cell line cultures. Intestinal organoids are affecting a wide variety of research into gastrointestinal pathology. The purpose of this review is to discuss the current state-of-the-art and future effect of research using enteroids and colonoids (organoids grown from the small and large intestines, respectively).
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In JG, Foulke-Abel J, Estes MK, Zachos NC, Kovbasnjuk O, Donowitz M. Human mini-guts: new insights into intestinal physiology and host-pathogen interactions. Nat Rev Gastroenterol Hepatol 2016; 13:633-642. [PMID: 27677718 PMCID: PMC5079760 DOI: 10.1038/nrgastro.2016.142] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The development of indefinitely propagating human 'mini-guts' has led to a rapid advance in gastrointestinal research related to transport physiology, developmental biology, pharmacology, and pathophysiology. These mini-guts, also called enteroids or colonoids, are derived from LGR5+ intestinal stem cells isolated from the small intestine or colon. Addition of WNT3A and other growth factors promotes stemness and results in viable, physiologically functional human intestinal or colonic cultures that develop a crypt-villus axis and can be differentiated into all intestinal epithelial cell types. The success of research using human enteroids has highlighted the limitations of using animals or in vitro, cancer-derived cell lines to model transport physiology and pathophysiology. For example, curative or preventive therapies for acute enteric infections have been limited, mostly due to the lack of a physiological human intestinal model. However, the human enteroid model enables specific functional studies of secretion and absorption in each intestinal segment as well as observations of the earliest molecular events that occur during enteric infections. This Review describes studies characterizing these human mini-guts as a physiological model to investigate intestinal transport and host-pathogen interactions.
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Affiliation(s)
- Julie G In
- Department of Medicine, Division of Gastroenterology, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, Maryland 21205, USA
| | - Jennifer Foulke-Abel
- Department of Medicine, Division of Gastroenterology, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, Maryland 21205, USA
| | - Mary K Estes
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
| | - Nicholas C Zachos
- Department of Medicine, Division of Gastroenterology, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, Maryland 21205, USA
| | - Olga Kovbasnjuk
- Department of Medicine, Division of Gastroenterology, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, Maryland 21205, USA
| | - Mark Donowitz
- Department of Medicine, Division of Gastroenterology, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, Maryland 21205, USA
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25
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Abstract
Several members of the SLC9A family of Na+/H+ exchangers are expressed in the gut, with varying expression patterns and cellular localization. Not only do they participate in the regulation of basic epithelial cell functions, including control of transepithelial Na+ absorption, intracellular pH (pH i ), cell volume, and nutrient absorption, but also in cellular proliferation, migration, and apoptosis. Additionally, they modulate the extracellular milieu in order to facilitate other nutrient absorption and to regulate the intestinal microbial microenvironment. Na+/H+ exchangers are frequent targets of inhibition in gastrointestinal pathologies, either by intrinsic factors (e.g. bile acids, inflammatory mediators) or infectious agents and associated microbial toxins. Based on emerging evidence, disruption of NHE activity via impaired expression or function of respective isoforms may contribute not only to local and systemic electrolyte imbalance, but also to the disease severity via multiple mechanisms. Here, we review the current state of knowledge about the roles Na+/H+ exchangers play in the pathogenesis of disorders of diverse origin and affecting a range of GI tissues.
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Affiliation(s)
- Michael A. Gurney
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona, Tucson, Arizona
| | - Daniel Laubitz
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona, Tucson, Arizona
| | - Fayez K. Ghishan
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona, Tucson, Arizona
| | - Pawel R. Kiela
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona, Tucson, Arizona,Department of Immunobiology, University of Arizona, Tucson, Arizona,Correspondence Address correspondence to: Pawel R. Kiela, DVM, PhD, Department of Pediatrics, University of Arizona, 1501 North Campbell Avenue, Tucson, Arizona 85724. fax: (520) 626-4141.Department of Pediatrics, University of Arizona1501 North Campbell AvenueTucsonArizona 85724
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26
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Shawki A, Engevik MA, Kim RS, Knight PB, Baik RA, Anthony SR, Worrell RT, Shull GE, Mackenzie B. Intestinal brush-border Na+/H+ exchanger-3 drives H+-coupled iron absorption in the mouse. Am J Physiol Gastrointest Liver Physiol 2016; 311:G423-30. [PMID: 27390324 PMCID: PMC5076011 DOI: 10.1152/ajpgi.00167.2016] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/29/2016] [Indexed: 01/31/2023]
Abstract
Divalent metal-ion transporter-1 (DMT1), the principal mechanism by which nonheme iron is taken up at the intestinal brush border, is energized by the H(+)-electrochemical potential gradient. The provenance of the H(+) gradient in vivo is unknown, so we have explored a role for brush-border Na(+)/H(+) exchanger (NHE) isoforms by examining iron homeostasis and intestinal iron handling in mice lacking NHE2 or NHE3. We observed modestly depleted liver iron stores in NHE2-null (NHE2(-/-)) mice stressed on a low-iron diet but no change in hematological or blood iron variables or the expression of genes associated with iron metabolism compared with wild-type mice. Ablation of NHE3 strongly depleted liver iron stores, regardless of diet. We observed decreases in blood iron variables but no overt anemia in NHE3-null (NHE3(-/-)) mice on a low-iron diet. Intestinal expression of DMT1, the apical surface ferrireductase cytochrome b reductase-1, and the basolateral iron exporter ferroportin was upregulated in NHE3(-/-) mice, and expression of liver Hamp1 (hepcidin) was suppressed compared with wild-type mice. Absorption of (59)Fe from an oral dose was substantially impaired in NHE3(-/-) compared with wild-type mice. Our data point to an important role for NHE3 in generating the H(+) gradient that drives DMT1-mediated iron uptake at the intestinal brush border.
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Affiliation(s)
- Ali Shawki
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; Systems Biology and Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio; and
| | - Melinda A Engevik
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; Systems Biology and Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio; and
| | - Robert S Kim
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Patrick B Knight
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Rusty A Baik
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Sarah R Anthony
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Roger T Worrell
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; Systems Biology and Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio; and
| | - Gary E Shull
- Systems Biology and Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio; and Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Bryan Mackenzie
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; Systems Biology and Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio; and
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McKenney ES, Kendall MM. Microbiota and pathogen 'pas de deux': setting up and breaking down barriers to intestinal infection. Pathog Dis 2016; 74:ftw051. [PMID: 27252177 PMCID: PMC5985477 DOI: 10.1093/femspd/ftw051] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/04/2016] [Accepted: 05/24/2016] [Indexed: 02/07/2023] Open
Abstract
The gut microbiota plays essential roles in human health and disease. In this review, we focus on the role of the intestinal microbiota in promoting resistance to infection by bacterial pathogens as well as how pathogens overcome this barrier. We discuss how the resident microbiota restricts growth and colonization of invading pathogens by limiting availability of nutrients and through generation of a hostile environment. Additionally, we examine how microbiota-derived signaling molecules interfere with bacterial virulence. In turn, we discuss how pathogens exploit non-competitive metabolites to replicate in vivo as well as to precisely control virulence and cause disease. This bacterial two step of creating and overcoming challenges important in preventing and establishing infection highlights the complexities of elucidating interactions between the commensal bacteria and pathogens. Better understanding of microbiota-pathogen interplay will have significant implications for developing novel therapeutics to treat infectious diseases.
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Affiliation(s)
- Elizabeth S McKenney
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Melissa M Kendall
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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28
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Bai X, Dee R, Mangum KD, Mack CP, Taylor JM. RhoA signaling and blood pressure: The consequence of failing to “Tone it Down”. World J Hypertens 2016; 6:18-35. [DOI: 10.5494/wjh.v6.i1.18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/24/2015] [Accepted: 01/22/2016] [Indexed: 02/06/2023] Open
Abstract
Uncontrolled high blood pressure is a major risk factor for heart attack, stroke, and kidney failure and contributes to an estimated 25% of deaths worldwide. Despite numerous treatment options, estimates project that reasonable blood pressure (BP) control is achieved in only about half of hypertensive patients. Improvements in the detection and management of hypertension will undoubtedly be accomplished through a better understanding of the complex etiology of this disease and a more comprehensive inventory of the genes and genetic variants that influence BP regulation. Recent studies (primarily in pre-clinical models) indicate that the small GTPase RhoA and its downstream target, Rho kinase, play an important role in regulating BP homeostasis. Herein, we summarize the underlying mechanisms and highlight signaling pathways and regulators that impart tight spatial-temporal control of RhoA activity. We also discuss known allelic variations in the RhoA pathway and consider how these polymorphisms may affect genetic risk for hypertension and its clinical manifestations. Finally, we summarize the current (albeit limited) clinical data on the efficacy of targeting the RhoA pathway in hypertensive patients.
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29
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Sodium-Proton (Na+/H+) Antiporters: Properties and Roles in Health and Disease. Met Ions Life Sci 2016; 16:391-458. [DOI: 10.1007/978-3-319-21756-7_12] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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30
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Engevik MA, Engevik KA, Yacyshyn MB, Wang J, Hassett DJ, Darien B, Yacyshyn BR, Worrell RT. Human Clostridium difficile infection: inhibition of NHE3 and microbiota profile. Am J Physiol Gastrointest Liver Physiol 2015; 308:G497-509. [PMID: 25552580 PMCID: PMC4422371 DOI: 10.1152/ajpgi.00090.2014] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Clostridium difficile infection (CDI) is principally responsible for hospital acquired, antibiotic-induced diarrhea and colitis and represents a significant financial burden on our healthcare system. Little is known about C. difficile proliferation requirements, and a better understanding of these parameters is critical for development of new therapeutic targets. In cell lines, C. difficile toxin B has been shown to inhibit Na(+)/H(+) exchanger 3 (NHE3) and loss of NHE3 in mice results in an altered intestinal environment coupled with a transformed gut microbiota composition. However, this has yet to be established in vivo in humans. We hypothesize that C. difficile toxin inhibits NHE3, resulting in alteration of the intestinal environment and gut microbiota. Our results demonstrate that CDI patient biopsy specimens have decreased NHE3 expression and CDI stool has elevated Na(+) and is more alkaline compared with stool from healthy individuals. CDI stool microbiota have increased Bacteroidetes and Proteobacteria and decreased Firmicutes phyla compared with healthy subjects. In vitro, C. difficile grows optimally in the presence of elevated Na(+) and alkaline pH, conditions that correlate to changes observed in CDI patients. To confirm that inhibition of NHE3 was specific to C. difficile, human intestinal organoids (HIOs) were injected with C. difficile or healthy and CDI stool supernatant. Injection of C. difficile and CDI stool decreased NHE3 mRNA and protein expression compared with healthy stool and control HIOs. Together these data demonstrate that C. difficile inhibits NHE3 in vivo, which creates an altered environment favored by C. difficile.
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Affiliation(s)
- Melinda A. Engevik
- 1Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio;
| | - Kristen A. Engevik
- 1Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio;
| | - Mary Beth Yacyshyn
- 3Department of Medicine Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio;
| | - Jiang Wang
- 4Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio;
| | - Daniel J. Hassett
- 2Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio;
| | - Benjamin Darien
- 5Department of Animal Health and Biomedical Sciences, University Wisconsin, Madison, Wisconsin; and
| | - Bruce R. Yacyshyn
- 3Department of Medicine Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio; ,6Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Roger T. Worrell
- 1Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; ,6Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio
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31
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Engevik MA, Engevik KA, Yacyshyn MB, Wang J, Hassett DJ, Darien B, Yacyshyn BR, Worrell RT. Human Clostridium difficile infection: inhibition of NHE3 and microbiota profile. Am J Physiol Gastrointest Liver Physiol 2015. [PMID: 25552580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Clostridium difficile infection (CDI) is principally responsible for hospital acquired, antibiotic-induced diarrhea and colitis and represents a significant financial burden on our healthcare system. Little is known about C. difficile proliferation requirements, and a better understanding of these parameters is critical for development of new therapeutic targets. In cell lines, C. difficile toxin B has been shown to inhibit Na(+)/H(+) exchanger 3 (NHE3) and loss of NHE3 in mice results in an altered intestinal environment coupled with a transformed gut microbiota composition. However, this has yet to be established in vivo in humans. We hypothesize that C. difficile toxin inhibits NHE3, resulting in alteration of the intestinal environment and gut microbiota. Our results demonstrate that CDI patient biopsy specimens have decreased NHE3 expression and CDI stool has elevated Na(+) and is more alkaline compared with stool from healthy individuals. CDI stool microbiota have increased Bacteroidetes and Proteobacteria and decreased Firmicutes phyla compared with healthy subjects. In vitro, C. difficile grows optimally in the presence of elevated Na(+) and alkaline pH, conditions that correlate to changes observed in CDI patients. To confirm that inhibition of NHE3 was specific to C. difficile, human intestinal organoids (HIOs) were injected with C. difficile or healthy and CDI stool supernatant. Injection of C. difficile and CDI stool decreased NHE3 mRNA and protein expression compared with healthy stool and control HIOs. Together these data demonstrate that C. difficile inhibits NHE3 in vivo, which creates an altered environment favored by C. difficile.
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Affiliation(s)
- Melinda A Engevik
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Kristen A Engevik
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Mary Beth Yacyshyn
- Department of Medicine Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Jiang Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Daniel J Hassett
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Benjamin Darien
- Department of Animal Health and Biomedical Sciences, University Wisconsin, Madison, Wisconsin; and
| | - Bruce R Yacyshyn
- Department of Medicine Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio; Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Roger T Worrell
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio
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32
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Loirand G, Pacaud P. Involvement of Rho GTPases and their regulators in the pathogenesis of hypertension. Small GTPases 2014; 5:1-10. [PMID: 25496262 DOI: 10.4161/sgtp.28846] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Proper regulation of arterial blood pressure is essential to allow permanent adjustment of nutrient and oxygen supply to organs and tissues according to their need. This is achieved through highly coordinated regulation processes controlling vascular resistance through modulation of arterial smooth muscle contraction, cardiac output, and kidney function. Members of the Rho family of small GTPases, in particular RhoA and Rac1, have been identified as key signaling molecules playing important roles in several different steps of these regulatory processes. Here, we review the current state of knowledge regarding the involvement of Rho GTPase signaling in the control of blood pressure and the pathogenesis of hypertension. We describe how knockout models in mouse, genetic, and pharmacological studies in human have been useful to address this question.
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Key Words
- AT1 receptor, type 1 Ang II receptor
- Ang II, angiotensine II
- ENaCs, epithelial Na+ channels
- Et-1, endothelin-1
- GAPs, GTPase-activating proteins
- GEFs, exchange factors
- GTPase activating proteins
- GTPases
- MLC, 20 kDa-myosin light chain
- MLCK, MLC kinase
- MLCP, MLC phosphatase
- NA, noradrenaline
- NHE3, sodium-hydrogen exchanger isoform 3.
- NO, nitric oxide
- NTS, nucleus tractus solitaries
- PDE5, type 5 phosphodiesterase
- PKG, cGMP-dependent protein kinase
- Rock, Rho-kinase
- SHR, spontaneously hypertensive rats
- SHRSP, stroke-prone SHR
- TxA2, thromboxane A2
- artery
- blood pressure
- cardiovascular
- eNOS, endothelial NO synthase
- exchange factors
- signal transduction
- small G proteins
- smooth muscle
- vasoconstriction
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Cha B, Chen T, Sarker R, Yang J, Raben D, Tse CM, Kovbasnjuk O, Donowitz M. Lysophosphatidic acid stimulation of NHE3 exocytosis in polarized epithelial cells occurs with release from NHERF2 via ERK-PLC-PKCδ signaling. Am J Physiol Cell Physiol 2014; 307:C55-65. [PMID: 24760985 PMCID: PMC4080180 DOI: 10.1152/ajpcell.00045.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/03/2014] [Indexed: 01/19/2023]
Abstract
The Na(+)/H(+) exchanger 3 (NHE3) is a brush border (BB) Na(+)/H(+) antiporter that accounts for the majority of physiologic small intestinal and renal Na(+) absorption. It is regulated physiologically and in disease via changes in endocytosis/exocytosis. Paradoxically, NHE3 is fixed to the microvillar (MV) actin cytoskeleton and has little basal mobility. This fixation requires NHE3 binding to the multi-PDZ domain scaffold proteins Na(+)/H(+) exchanger regulatory factor (NHERF)1 and NHERF2 and to ezrin. Coordinated release of NHE3 from the MV cytoskeleton has been demonstrated during both stimulation and inhibition of NHE3. However, the signaling molecules involved in coordinating NHE3 trafficking and cytoskeletal association have not been identified. This question was addressed by studying lysophosphatidic acid (LPA) stimulation of NHE3 in polarized renal proximal tubule opossum kidney (OK) cells that occurs via apical LPA5 receptors and is NHERF2 dependent and mediated by epidermal growth factor receptor (EGFR), Rho/Rho-associated kinase (ROCK), and ERK. NHE3 activity was determined by BCECF/fluorometry and NHE3 microvillar mobility by FRAP/confocal microscopy using NHE3-EGFP. Apical LPA (3 μM)/LPA5R stimulated NHE3 activity, increased NHE3 mobility, and decreased the NHE3/NHERF2 association. The LPA stimulation of NHE3 was also PKCδ dependent. PKCδ was necessary for LPA stimulation of NHE3 mobility and NHE3/NHERF2 association. Moreover, the LPA-induced translocation to the membrane of PKCδ was both ERK and phospholipase C dependent with ERK acting upstream of PLC. We conclude that LPA stimulation of NHE3 exocytosis includes a signaling pathway that regulates fixation of NHE3 to the MV cytoskeleton. This involves a signaling module consisting of ERK-PLC-PKCδ, which dynamically and reversibly releases NHE3 from NHERF2 to contribute to the changes in NHE3 MV mobility.
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Affiliation(s)
- Boyoung Cha
- Departments of Physiology and Medicine, Gastrointestinal Division, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Tiane Chen
- Departments of Physiology and Medicine, Gastrointestinal Division, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Rafiquel Sarker
- Departments of Physiology and Medicine, Gastrointestinal Division, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Jianbo Yang
- Departments of Physiology and Medicine, Gastrointestinal Division, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Daniel Raben
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - C Ming Tse
- Departments of Physiology and Medicine, Gastrointestinal Division, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Olga Kovbasnjuk
- Departments of Physiology and Medicine, Gastrointestinal Division, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Mark Donowitz
- Departments of Physiology and Medicine, Gastrointestinal Division, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and
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No YR, He P, Yoo BK, Yun CC. Unique regulation of human Na+/H+ exchanger 3 (NHE3) by Nedd4-2 ligase that differs from non-primate NHE3s. J Biol Chem 2014; 289:18360-72. [PMID: 24831004 DOI: 10.1074/jbc.m113.541706] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Na(+)/H(+) exchanger NHE3 expressed in the intestine and kidney plays a major role in NaCl and HCO3 (-) absorption that is closely linked to fluid absorption and blood pressure regulation. The Nedd4 family of E3 ubiquitin ligases interacts with a number of transporters and channels via PY motifs. A comparison of NHE3 sequences revealed the presence of PY motifs in NHE3s from human and several non-human primates but not in non-primate NHE3s. In this study we evaluated the differences between human and non-primate NHE3s in ubiquitination and interaction with Nedd4-2. We found that Nedd4-2 ubiquitinated human NHE3 (hNHE3) and altered its expression and activity. Surprisingly, rat NHE3 co-immunoprecipitated Nedd4-2, but its expression and activity were not altered by silencing of Nedd4-2. Ubiquitination by Nedd4-2 rendered hNHE3 to undergo internalization at a significantly greater rate than non-primate NHE3s without altering protein stability. Insertion of a PY motif in rabbit NHE3 recapitulated the interaction with Nedd4-2 and enhanced internalization. Thus, we propose a new model where disruption of Nedd4-2 interaction elevates hNHE3 expression and activity.
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Affiliation(s)
- Yi Ran No
- From the Division of Digestive Diseases, Department of Medicine and
| | - Peijian He
- From the Division of Digestive Diseases, Department of Medicine and
| | - Byong Kwon Yoo
- From the Division of Digestive Diseases, Department of Medicine and
| | - C Chris Yun
- From the Division of Digestive Diseases, Department of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322
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35
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Engevik MA, Aihara E, Montrose MH, Shull GE, Hassett DJ, Worrell RT. Loss of NHE3 alters gut microbiota composition and influences Bacteroides thetaiotaomicron growth. Am J Physiol Gastrointest Liver Physiol 2013; 305:G697-711. [PMID: 24072680 PMCID: PMC3840232 DOI: 10.1152/ajpgi.00184.2013] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 09/20/2013] [Indexed: 01/31/2023]
Abstract
Changes in the intestinal microbiota have been linked to diabetes, obesity, inflammatory bowel disease, and Clostridium difficile (C. difficile)-associated disease. Despite this, it remains unclear how the intestinal environment, set by ion transport, affects luminal and mucosa-associated bacterial composition. Na(+)/H(+)-exchanger isoform 3 (NHE3), a target of C. difficile toxin B, plays an integral role in intestinal Na(+) absorption. Thus the NHE3-deficient mouse model was chosen to examine the effect of pH and ion composition on bacterial growth. We hypothesized that ion transport-induced change in the intestinal environment would lead to alteration of the microbiota. Region-specific changes in ion composition and pH correlated with region-specific alteration of luminal and mucosal-associated bacteria with general decreases in Firmicutes and increases in Bacteroidetes members. Bacteroides thetaiotaomicron (B. thetaiotaomicron) increased in NHE3(-/-) terminal ileum and was examined in vitro to determine whether altered Na(+) was sufficient to affect growth. Increased in vitro growth of B. thetaiotaomicron occurred in 43 mM Na(+) correlating with the NHE3(-/-) mouse terminal ileum [Na(+)]. NHE3(-/-) terminal ileum displayed increased fut2 mRNA and fucosylation correlating with B. thetaiotaomicron growth. Inoculation of B. thetaiotaomicron in wild-type and NHE3(-/-) terminal ileum organoids displayed increased fut2 and fucosylation, indicating that B. thetaiotaomicron alone is sufficient for the increased fucosylation seen in vivo. These data demonstrate that loss of NHE3 alters the intestinal environment, leading to region-specific changes in bacteria, and shed light on the growth requirements of some gut microbiota members, which is vital for creating better treatments of complex diseases with an altered gut microbiota.
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Affiliation(s)
- Melinda A Engevik
- Dept. of Molecular and Cellular Physiology, Univ. of Cincinnati College of Medicine, Cincinnati, OH 45267.
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36
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Loirand G, Sauzeau V, Pacaud P. Small G Proteins in the Cardiovascular System: Physiological and Pathological Aspects. Physiol Rev 2013; 93:1659-720. [DOI: 10.1152/physrev.00021.2012] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Small G proteins exist in eukaryotes from yeast to human and constitute the Ras superfamily comprising more than 100 members. This superfamily is structurally classified into five families: the Ras, Rho, Rab, Arf, and Ran families that control a wide variety of cell and biological functions through highly coordinated regulation processes. Increasing evidence has accumulated to identify small G proteins and their regulators as key players of the cardiovascular physiology that control a large panel of cardiac (heart rhythm, contraction, hypertrophy) and vascular functions (angiogenesis, vascular permeability, vasoconstriction). Indeed, basal Ras protein activity is required for homeostatic functions in physiological conditions, but sustained overactivation of Ras proteins or spatiotemporal dysregulation of Ras signaling pathways has pathological consequences in the cardiovascular system. The primary object of this review is to provide a comprehensive overview of the current progress in our understanding of the role of small G proteins and their regulators in cardiovascular physiology and pathologies.
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Affiliation(s)
- Gervaise Loirand
- INSERM, UMR S1087; University of Nantes; and CHU Nantes, l'Institut du Thorax, Nantes, France
| | - Vincent Sauzeau
- INSERM, UMR S1087; University of Nantes; and CHU Nantes, l'Institut du Thorax, Nantes, France
| | - Pierre Pacaud
- INSERM, UMR S1087; University of Nantes; and CHU Nantes, l'Institut du Thorax, Nantes, France
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Donowitz M, Ming Tse C, Fuster D. SLC9/NHE gene family, a plasma membrane and organellar family of Na⁺/H⁺ exchangers. Mol Aspects Med 2013; 34:236-51. [PMID: 23506868 DOI: 10.1016/j.mam.2012.05.001] [Citation(s) in RCA: 201] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 03/09/2012] [Indexed: 12/24/2022]
Abstract
This brief review of the human Na/H exchanger gene family introduces a new classification with three subgroups to the SLC9 gene family. Progress in the structure and function of this gene family is reviewed with structure based on homology to the bacterial Na/H exchanger NhaA. Human diseases which result from genetic abnormalities of the SLC9 family are discussed although the exact role of these transporters in causing any disease is not established, other than poorly functioning NHE3 in congenital Na diarrhea.
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Affiliation(s)
- Mark Donowitz
- Departments of Medicine and Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
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Hell M, Bernhofer C, Stalzer P, Kern JM, Claassen E. Probiotics in Clostridium difficile infection: reviewing the need for a multistrain probiotic. Benef Microbes 2013; 4:39-51. [PMID: 23434948 DOI: 10.3920/bm2012.0049] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In the past two years an enormous amount of molecular, genetic, metabolomic and mechanistic data on the host-bacterium interaction, a healthy gut microbiota and a possible role for probiotics in Clostridium difficile infection (CDI) has been accumulated. Also, new hypervirulent strains of C. difficile have emerged. Yet, clinical trials in CDI have been less promising than in antibiotic associated diarrhoea in general, with more meta-analysis than primary papers on CDI-clinical-trials. The fact that C. difficile is a spore former, producing at least three different toxins has not yet been incorporated in the rational design of probiotics for (recurrent) CDI. Here we postulate that the plethora of effects of C. difficile and the vast amount of data on the role of commensal gut residents and probiotics point towards a multistrain mixture of probiotics to reduce CDI, but also to limit (nosocomial) transmission and/or endogenous reinfection. On the basis of a retrospective chart review of a series of ten CDI patients where recurrence was expected, all patients on adjunctive probiotic therapy with multistrain cocktail (Ecologic®AAD/OMNiBiOTiC® 10) showed complete clinical resolution. This result, and recent success in faecal transplants in CDI treatment, are supportive for the rational design of multistrain probiotics for CDI.
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Affiliation(s)
- M Hell
- Department of Hospital Epidemiology and Infection Control, Salzburg University Hospital, Paracelsus Medical University, Strubergasse 21, 5020 Salzburg, Austria
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Ezrin is required for the functional regulation of the epithelial sodium proton exchanger, NHE3. PLoS One 2013; 8:e55623. [PMID: 23405179 PMCID: PMC3566197 DOI: 10.1371/journal.pone.0055623] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 12/31/2012] [Indexed: 11/19/2022] Open
Abstract
The sodium hydrogen exchanger isoform 3 (NHE3) mediates absorption of sodium, bicarbonate and water from renal and intestinal lumina. This activity is fundamental to the maintenance of a physiological plasma pH and blood pressure. To perform this function NHE3 must be present in the apical membrane of renal tubular and intestinal epithelia. The molecular determinants of this localization have not been conclusively determined, although linkage to the apical actin cytoskeleton through ezrin has been proposed. We set out to evaluate this hypothesis. Functional studies of NHE3 activity were performed on ezrin knockdown mice (Vil2kd/kd) and NHE3 activity similar to wild-type animals detected. Interpretation of this finding was difficult as other ERM (ezrin/radixin/moesin) proteins were present. We therefore generated an epithelial cell culture model where ezrin was the only detectable ERM. After knockdown of ezrin expression with siRNA, radixin and moesin expression remained undetectable. Consistent with the animal ultrastructural data, cells lacking ezrin retained an epithelial phenotype but had shortened and thicker microvilli. NHE3 localization was identical to cells transfected with non-targeting siRNA. The attachment of NHE3 to the apical cytoskeleton was unaltered as assessed by fluorescent recovery after photobleaching (FRAP) and the solubility of NHE3 in Triton X-100. Baseline NHE3 activity was unaltered, however, cAMP-dependent inhibition of NHE3 was largely lost even though NHE3 was phosphorylated at serines 552 and 605. Thus, ezrin is not necessary for the apical localization, attachment to the cytoskeleton, baseline activity or cAMP induced phosphrylation of NHE3, but instead is required for cAMP mediated inhibition.
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Maniti O, Carvalho K, Picart C. Model membranes to shed light on the biochemical and physical properties of ezrin/radixin/moesin. Biochimie 2013; 95:3-11. [PMID: 23041444 PMCID: PMC4112940 DOI: 10.1016/j.biochi.2012.09.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 09/28/2012] [Indexed: 10/27/2022]
Abstract
Ezrin, radixin and moesin (ERM) proteins are now more and more recognized to play a key role in a large number of important physiological processes such as morphogenesis, cancer metastasis and virus infection. Several recent reviews extensively discuss their biological functions [1 -4 ]. In this review, we will first remind the main features of this family of proteins, which are now known as linkers and regulators of the plasma membrane/cytoskeleton linkage. We will then briefly review their implication in pathological processes such as cancer and viral infection. In a second part, we will focus on biochemical and biophysical approaches to study ERM interaction with lipid membranes and conformational change in well-defined environments. In vitro studies using biomimetic lipid membranes, especially large unilamellar vesicles (LUVs), giant unilamellar vesicles (GUVs) and supported lipid bilayers (SLBs) and recombinant proteins help to understand the molecular mechanism of conformational activation of ERM proteins. These tools are aimed to decorticate the different steps of the interaction, to simplify the experiments performed in vivo in much more complex biological environments.
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Affiliation(s)
- Ofélia Maniti
- CNRS UMR 5628 (LMGP), Grenoble Institute of Technology and CNRS, 3 parvis Louis Néel, F-38016 Grenoble Cedex, France
- Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, UMR 5246, CNRS, Université de Lyon, Université Lyon 1, INSA-Lyon, CPE-Lyon, 43 Bd du 11 Novembre 1918, F-69622 Villeurbanne, France
| | - Kevin Carvalho
- Institut Curie, centre de recherche and CNRS UMR 168, 11 rue Pierre et Marie Curie, Paris, F-75248 cedex 5
| | - Catherine Picart
- CNRS UMR 5628 (LMGP), Grenoble Institute of Technology and CNRS, 3 parvis Louis Néel, F-38016 Grenoble Cedex, France
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Girardi ACC, Di Sole F. Deciphering the mechanisms of the Na+/H+ exchanger-3 regulation in organ dysfunction. Am J Physiol Cell Physiol 2012; 302:C1569-87. [DOI: 10.1152/ajpcell.00017.2012] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The Na+/H+ exchanger-3 (NHE3) belongs to the mammalian NHE protein family and catalyzes the electro-neutral exchange of extracellular sodium for intracellular proton across cellular membranes. Its transport function is of essential importance for the maintenance of the body's salt and water homeostasis as well as acid-base balance. Indeed, NHE3 activity is finely regulated by a variety of stimuli, both acutely and chronically, and its transport function is fundamental for a multiplicity of severe and world-wide infection-pathological conditions. This review aims to provide a concise overview of NHE3 physiology and discusses the role of NHE3 in clinical conditions of prominent importance, specifically in hypertension, diabetic nephropathy, heart failure, acute kidney injury, and diarrhea. Study of NHE3 function in models of these diseases has contributed to the deciphering of mechanisms that control the delicate ion balance disrupted in these disorders. The majority of the findings indicate that NHE3 transport function is activated before the onset of hypertension and inhibited thereafter; NHE3 transport function is also upregulated in diabetic nephropathy and heart failure, while it is reported to be downregulated in acute kidney injury and in diarrhea. The molecular mechanisms activated during these pathological conditions to regulate NHE3 transport function are examined with the aim of linking NHE3 dysfunction to the analyzed clinical disorders.
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Affiliation(s)
| | - Francesca Di Sole
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
- Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
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Besserer GM, Nicoll DA, Abramson J, Philipson KD. Characterization and purification of a Na+/Ca2+ exchanger from an archaebacterium. J Biol Chem 2012; 287:8652-9. [PMID: 22287543 DOI: 10.1074/jbc.m111.331280] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The superfamily of cation/Ca(2+) exchangers includes both Na(+)/Ca(2+) exchangers (NCXs) and Na(+)/Ca(2+),K(+) exchangers (NCKX) as the families characterized in most detail. These Ca(2+) transporters have prominent physiological roles. For example, NCX and NCKX are important in regulation of cardiac contractility and visual processes, respectively. The superfamily also has a large number of members of the YrbG family expressed in prokaryotes. However, no members of this family have been functionally expressed, and their transport properties are unknown. We have expressed, purified, and characterized a member of the YrbG family, MaX1 from Methanosarcina acetivorans. MaX1 catalyzes Ca(2+) uptake into membrane vesicles. The Ca(2+) uptake requires intravesicular Na(+) and is stimulated by an inside positive membrane potential. Despite very limited sequence similarity, MaX1 is a Na(+)/Ca(2+) exchanger with kinetic properties similar to those of NCX. The availability of a prokaryotic Na(+)/Ca(2+) exchanger should facilitate structural and mechanistic investigations.
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Affiliation(s)
- Gabriel Mercado Besserer
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1751, USA
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43
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Zhu X, Cha B, Zachos NC, Sarker R, Chakraborty M, Chen TE, Kovbasnjuk O, Donowitz M. Elevated calcium acutely regulates dynamic interactions of NHERF2 and NHE3 proteins in opossum kidney (OK) cell microvilli. J Biol Chem 2011; 286:34486-96. [PMID: 21799002 DOI: 10.1074/jbc.m111.230219] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The brush border (BB) Na(+)/H(+) exchanger NHE3 is rapidly activated or inhibited by changes in trafficking, which mimics renal and intestinal physiology. However, there is a paradox in that NHE3 has limited mobility in the BB due to its binding to the multi-PDZ domain containing the NHERF family. To allow increased endocytosis, as occurs with elevated intracellular Ca(2+), we hypothesized that NHE3 had to be, at least transiently, released from the BB cytoskeleton. Because NHERF1 and -2 are localized at the BB, where they bind NHE3 as well as the cytoskeleton, we tested whether either or both might dynamically interact with NHE3 as part of Ca(2+) signaling. We employed FRET to study close association of NHE3 and these NHERFs and fluorescence recovery after photobleaching to monitor NHE3 mobility in the apical domain in polarized opossum kidney cells. Under basal conditions, NHERF2 and NHE3 exhibited robust FRET signaling. Within 1 min of A23187 (0.5 μm) exposure, the NHERF2-NHE3 FRET signal was abolished, and BB NHE3 mobility was transiently increased. The dynamics in FRET signal and NHE3 mobility correlated well with a change in co-precipitation of NHE3 and NHERF2 but not NHERF1. We conclude the following. 1) Under basal conditions, NHE3 closely associates with NHERF2 in opossum kidney cell microvilli. 2) Within 1 min of elevated Ca(2+), the close association of NHE3-NHERF2 is abolished but is re-established in ∼60 min. 3) The change in NHE3-NHERF2 association is accompanied by an increased BB mobile fraction of NHE3, which contributes to inhibition of NHE3 transport activity via increased endocytosis.
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Affiliation(s)
- Xinjun Zhu
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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44
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Shear stress-induced changes of membrane transporter localization and expression in mouse proximal tubule cells. Proc Natl Acad Sci U S A 2010; 107:21860-5. [PMID: 21106755 DOI: 10.1073/pnas.1015751107] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Our previous studies of microperfused single proximal tubule showed that flow-dependent Na(+) and HCO(3)(-) reabsorption is due to a modulation of both NHE3 and vacuolar H(+)-ATPase (V-ATPase) activity. An intact actin cytoskeleton was indicated to provide a structural framework for proximal tubule cells to transmit mechanical forces and subsequently modulate cellular functions. In this study, we have used mouse proximal tubule (MPT) cells as a model to study the role of fluid shear stress (FSS) on apical NHE3 and V-ATPase and basolateral Na/K-ATPase trafficking and expression. Our hypothesis is that FSS stimulates both apical and basolateral transporter expression and trafficking, which subsequently mediates salt and volume reabsorption. We exposed MPT cells to 0.2 dynes/cm(2) FSS for 3 h and performed confocal microscopy and Western blot analysis to compare the localization and expression of both apical and basolateral transporters in control cells and cells subjected to FSS. Our findings show that FSS leads to an increment in the amount of protein expression, and a translocation of apical NHE3 and V-ATPase from the intracellular compartment to the apical plasma membrane and Na/K-ATPase to the basolateral membrane. Disrupting actin by cytochalasin D blocks the FSS-induced changes in NHE3 and Na/K-ATPase, but not V-ATPase. In contrast, FSS-induced V-ATPase redistribution and expression are largely inhibited by colchicine, an agent that blocks microtubule polymerization. Our findings suggest that the actin cytoskeleton plays an important role in FSS-induced NHE3 and Na/K-ATPase trafficking, and an intact microtubule network is critical in FSS-induced modulation of V-ATPase in proximal tubule cells.
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Sun X, Savidge T, Feng H. The enterotoxicity of Clostridium difficile toxins. Toxins (Basel) 2010; 2:1848-80. [PMID: 22069662 PMCID: PMC3153265 DOI: 10.3390/toxins2071848] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 06/23/2010] [Accepted: 07/09/2010] [Indexed: 02/06/2023] Open
Abstract
The major virulence factors of Clostridium difficile infection (CDI) are two large exotoxins A (TcdA) and B (TcdB). However, our understanding of the specific roles of these toxins in CDI is still evolving. It is now accepted that both toxins are enterotoxic and proinflammatory in the human intestine. Both purified TcdA and TcdB are capable of inducing the pathophysiology of CDI, although most studies have focused on TcdA. C. difficile toxins exert a wide array of biological activities by acting directly on intestinal epithelial cells. Alternatively, the toxins may target immune cells and neurons once the intestinal epithelial barrier is disrupted. The toxins may also act indirectly by stimulating cells to produce chemokines, proinflammatory cytokines, neuropeptides and other neuroimmune signals. This review considers the mechanisms of TcdA- and TcdB-induced enterotoxicity, and recent developments in this field.
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Affiliation(s)
- Xingmin Sun
- Tufts Cummings School of Veterinary Medicine, North Grafton, MA, 01536, USA;
| | - Tor Savidge
- The University of Texas Medical Branch, Galveston, TX, 77555, USA;
| | - Hanping Feng
- Tufts Cummings School of Veterinary Medicine, North Grafton, MA, 01536, USA;
- Author to whom correspondence should be addressed; ; Tel.: +1-508-887-4252; Fax: +1-508-839-7911
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46
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Nighot PK, Moeser A, Ali RA, Blikslager AT, Koci MD. Astrovirus infection induces sodium malabsorption and redistributes sodium hydrogen exchanger expression. Virology 2010; 401:146-54. [PMID: 20219227 PMCID: PMC2862094 DOI: 10.1016/j.virol.2010.02.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 11/03/2009] [Accepted: 02/03/2010] [Indexed: 01/04/2023]
Abstract
Astroviruses are known to be a leading cause of diarrhea in infants and the immunocompromised; however, our understanding of this endemic pathogen is limited. Histological analyses of astrovirus pathogenesis demonstrate clinical disease is not associated with changes to intestinal architecture, inflammation, or cell death. Recent studies in vitro have suggested that astroviruses induce actin rearrangement leading to loss of barrier function. The current study used the type-2 turkey astrovirus (TAstV-2) and turkey poult model of astrovirus disease to examine how astrovirus infection affects the ultrastructure and electrophysiology of the intestinal epithelium. These data demonstrate that infection results in changes to the epithelial ultrastructure, rearrangement of F-actin, decreased absorption of sodium, as well as redistribution of the sodium/hydrogen exchanger 3 (NHE3) from the membrane to the cytoplasm. Collectively, these data suggest astrovirus infection induces sodium malabsorption, possibly through redistribution of specific sodium transporters, which results in the development of an osmotic diarrhea.
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Affiliation(s)
- Prashant K. Nighot
- Department of Clinical Sciences, North Carolina State University, Raleigh, NC
| | - Adam Moeser
- Department of Clinical Sciences, North Carolina State University, Raleigh, NC
| | - Rizwana A. Ali
- Department of Poultry Science, North Carolina State University, Raleigh, NC
| | | | - Matthew D Koci
- Department of Poultry Science, North Carolina State University, Raleigh, NC
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Mechanisms of the regulation of the intestinal Na+/H+ exchanger NHE3. J Biomed Biotechnol 2010; 2010:238080. [PMID: 20011065 PMCID: PMC2789519 DOI: 10.1155/2010/238080] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 09/11/2009] [Indexed: 01/25/2023] Open
Abstract
A major of Na+ absorptive process in the proximal part of intestine and kidney is electroneutral exchange of Na+ and H+ by Na+/H+ exchanger type 3 (NHE3). During the past decade, significant advance has been achieved in the mechanisms of NHE3 regulation. A bulk of the current knowledge on Na+/H+ exchanger regulation is based on heterologous expression of mammalian Na+/H+ exchangers in Na+/H+ exchanger deficient fibroblasts, renal epithelial, and intestinal epithelial cells. Based on the reductionist's approach, an understanding of NHE3 regulation has been greatly advanced. More recently, confirmations of in vitro studies have been made using animals deficient in one or more proteins but in some cases unexpected findings have emerged. The purpose of this paper is to provide a brief overview of recent progress in the regulation and functions of NHE3 present in the luminal membrane of the intestinal tract.
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48
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Lee JS, Lee YM, Kim JY, Park HW, Grinstein S, Orlowski J, Kim E, Kim KH, Lee MG. BetaPix up-regulates Na+/H+ exchanger 3 through a Shank2-mediated protein-protein interaction. J Biol Chem 2010; 285:8104-13. [PMID: 20080968 DOI: 10.1074/jbc.m109.055079] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Na(+)/H(+) exchanger 3 (NHE3) plays an important role in neutral Na(+) transport in mammalian epithelial cells. The Rho family of small GTPases and the PDZ (PSD-95/discs large/ZO-1) domain-based adaptor Shank2 are known to regulate the membrane expression and activity of NHE3. In this study we examined the role of betaPix, a guanine nucleotide exchange factor for the Rho GTPase and a strong binding partner to Shank2, in NHE3 regulation using integrated molecular and physiological approaches. Immunoprecipitation and pulldown assays revealed that NHE3, Shank2, and betaPix form a macromolecular complex when expressed heterologously in mammalian cells as well as endogenously in rat colon, kidney, and pancreas. In addition, these proteins co-segregated at the apical surface of rat colonic epithelial cells, as detected by immunofluorescence staining. When expressed in PS120/NHE3 cells, betaPix increased membrane expression and basal activity of NHE3. Interestingly, the effects of betaPix on NHE3 were abolished by cotransfection with dominant-negative Shank2 mutants and by treatment with Clostridium difficile toxin B, a Rho GTPase inhibitor, indicating that Shank2 and Rho GTPases are involved in betaPix-mediated NHE3 regulation. Knockdown of endogenous betaPix by RNA interference decreased Shank2-induced increase of NHE3 membrane expression in HEK 293T cells. These results indicate that betaPix up-regulates NHE3 membrane expression and activity by Shank2-mediated protein-protein interaction and by activating Rho GTPases in the apical regions of epithelial cells.
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Affiliation(s)
- Jung-Soo Lee
- Department of Pharmacology and Brain Korea 21 Project for Medical Science, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul 120-752, Korea
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Kiela PR, Laubitz D, Larmonier CB, Midura-Kiela MT, Lipko MA, Janikashvili N, Bai A, Thurston R, Ghishan FK. Changes in mucosal homeostasis predispose NHE3 knockout mice to increased susceptibility to DSS-induced epithelial injury. Gastroenterology 2009; 137:965-75, 975.e1-10. [PMID: 19450596 PMCID: PMC3454522 DOI: 10.1053/j.gastro.2009.05.043] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 05/04/2009] [Accepted: 05/14/2009] [Indexed: 12/27/2022]
Abstract
BACKGROUND & AIMS NHE3 is a target of inhibition by proinflammatory cytokines and pathogenic bacteria, an event contributing to diarrhea in infectious and idiopathic colitis. In mice, NHE3 deficiency leads to mild diarrhea, increased intestinal expression of interferon (IFN)-gamma, and distal colitis, suggesting its role in epithelial barrier homeostasis. Our aim was to investigate the role of NHE3 in maintaining mucosal integrity. METHODS Control or dextran sulfate sodium (DSS)-treated, 6- to 8-week-old wild-type (WT) and NHE3(-/-) mice were used for the experiments. Small intestines were dissected for further analysis. RESULTS NHE3(-/-) mice have elevated numbers of CD8alpha(+) T and natural killer cells in the intraepithelial lymphocytes and lamina propria lymphocytes compartments, representing the source of IFN-gamma. NHE3(-/-) mice display alterations in epithelial gene and protein expression patterns that predispose them to a high susceptibility to DSS, with accelerated mortality resulting from intestinal bleeding, hypovolemic shock, and sepsis, even at a very low DSS concentration. Microarray analysis and intestinal hemorrhage indicate that NHE3 deficiency predisposes mice to DSS-induced small intestinal injury, a segment never reported as affected by DSS, and demonstrate major differences in the colonic response to DSS challenge in WT and NHE3(-/-) mice. In NHE3(-/-) mice, broad-spectrum oral antibiotics or anti-asialo GM1 antibodies reduce the expression of IFN-gamma and iNOS to basal levels and delay but do not prevent severe mortality in response to DSS treatment. CONCLUSIONS These results suggest that NHE3 participates in mucosal responses to epithelial damage, acting as a modifier gene determining the extent of the gut inflammatory responses in the face of intestinal injury.
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Affiliation(s)
- Pawel R. Kiela
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona Health Sciences Center 1501 N. Campbell Ave, Tucson, AZ 85724
- Department of Immunobiology, University of Arizona Health Sciences Center, 1656 E. Mabel Street, Tucson, Arizona, 85724
| | - Daniel Laubitz
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona Health Sciences Center 1501 N. Campbell Ave, Tucson, AZ 85724
| | - Claire B. Larmonier
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona Health Sciences Center 1501 N. Campbell Ave, Tucson, AZ 85724
| | - Monica T. Midura-Kiela
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona Health Sciences Center 1501 N. Campbell Ave, Tucson, AZ 85724
| | - Maciej A. Lipko
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona Health Sciences Center 1501 N. Campbell Ave, Tucson, AZ 85724
| | - Nona Janikashvili
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona Health Sciences Center 1501 N. Campbell Ave, Tucson, AZ 85724
| | - Aiping Bai
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona Health Sciences Center 1501 N. Campbell Ave, Tucson, AZ 85724
| | - Robert Thurston
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona Health Sciences Center 1501 N. Campbell Ave, Tucson, AZ 85724
| | - Fayez K. Ghishan
- Department of Pediatrics, Steele Children’s Research Center, University of Arizona Health Sciences Center 1501 N. Campbell Ave, Tucson, AZ 85724
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Di Sole F, Babich V, Moe OW. The calcineurin homologous protein-1 increases Na(+)/H(+) -exchanger 3 trafficking via ezrin phosphorylation. J Am Soc Nephrol 2009; 20:1776-86. [PMID: 19556366 DOI: 10.1681/asn.2008121255] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The Na(+)/H(+)-exchanger 3 (NHE3) is essential for regulation of Na(+) transport in the renal and intestinal epithelium. Although changes in cell surface abundance control NHE3 function, the molecular signals that regulate NHE3 surface expression are not well defined. We found that overexpression of the calcineurin homologous protein-1 (CHP1) in opossum kidney cells increased NHE3 transport activity, surface protein abundance, and ezrin phosphorylation. CHP1 knockdown by small interfering RNA had the opposite effects. Overexpression of wild-type ezrin increased both NHE3 transport activity and surface protein abundance, confirming that NHE3 is downstream of ezrin. Expression of a pseudophosphorylated ezrin enhanced these effects, whereas expression of an ezrin variant that could not be phosphorylated prevented the downstream effects on NHE3. Furthermore, CHP1 knockdown reversed the activation of NHE3 by wild-type ezrin but not by the pseudophosphorylated ezrin. Taken together, these results demonstrate that CHP1 increases NHE3 abundance and constitutive function in a manner dependent on ezrin phosphorylation.
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Affiliation(s)
- Francesca Di Sole
- Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-8885, USA.
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