Nasal-to-brain (NtoB) delivery is a noninvasive approach that uses the nasal cavity as a pathway to transport therapeutic agents directly to the brain. This approach bypasses systemic circulation and avoids the blood-brain barrier (BBB). Transcranial ultrasound, coupled with microbubbles (MB), is a technique used to oscillate and generate acoustic cavitation to open the capillary tight junctions of BBB temporarily. Its efficacy in facilitating NtoB delivery has been demonstrated in vivo. However, while opening the BBB, sonication with MB poses the risk of cerebral microhemorrhage or brain tissue damage due to sonication-induced physical injury. This study aimed to assess the effectiveness of low-intensity ultrasound treatment to facilitate NtoB delivery in a mouse model without using MB.

In this study, 10-kDa dextran was administered intranasally (IN), and transcranial planar US was applied to the entire mouse brain without MB assistance. Ex-vivo whole brain imaging via fluorescence macroscopy, brain slice analysis with fluorescence microscope, and quantification of dextran concentration in distinct brain regions were conducted to compare the IN-only, IN combined with US (IN+US), and sham groups. For the trigeminal nerves (TN), fluorescence macroscopy, microscopy, and TN concentration quantification were performed to compare the three groups.

Whole brain imaging revealed that US facilitated the IN delivery of dextran to the olfactory bulb (OB) in the IN+US group compared with that in the IN-only and sham groups; however, this difference was not observed after a 24 h follow-up. Conversely, brain slice images showed that the tracer was delivered to the OB, cerebral cortex, striatum and brainstem in the IN+US group, but this finding was not observed in the IN-only group at the 4 h mark. The quantification of fluorescence intensity at two follow-up time points revealed no significant difference between the IN and IN+US groups in these specific regions. Dextran concentration analysis for distinct brain areas and TN showed that ultrasound significantly increased the tracer concentration delivered to the OB and TN in the IN+US group at the 4 h mark compared with that in the IN-only and sham groups; however, this effect was not sustained at 24 h. Confocal microscopy indicated that the dextran tracer accumulated in the perivascular space along the microvascular structures.

We demonstrated the efficacy of low-intensity ultrasound without using MB, in enhancing nose-to-OB and nose-to-TN drug delivery, and proposed the potential for future clinical application. Thus, we showed that this approach was safe, without evidence of microhemorrhage or brain tissue damage.

Glioblastoma (GBM) remains a formidable challenge due to its aggressive nature, protected location within the brain, and resistance to conventional treatments. Its complex tumor microenvironment (TME), coupled with the blood-brain barrier (BBB), hinders drug delivery leading to poor treatment outcomes. Nanoparticles (NPs) offer a promising solution, as they can improve the pharmacokinetic properties of anticancer agents. By functionalizing NPs with targeting molecules, researchers aim to enhance drug concentration in the brain. However, developing effective NP-based therapies requires robust in vitro models that accurately capture the complexities of GBM. Two-dimensional (2D) and three-dimensional (3D) cell culture models provide a versatile platform for studying NP-cell interactions. By customizing cell types, incorporating TME components, and adjusting flow conditions, researchers can tailor these models to specific research questions. While 2D models offer a simpler starting point, 3D models, such as multicellular spheroids and organoids, can more accurately replicate the complex TME, including the BBB and tumor heterogeneity. These models enable a more comprehensive evaluation of NP efficacy and safety, ultimately accelerating drug development and reducing reliance on animal testing.

Colostrum, the initial mammary secretion produced by various mammals following birth, is a conduit for maternal immunity transfer in diverse mammalian species. Concurrently, many cellular processes are occurring in the neonatal small intestine to prepare it to receive molecular signals from a superfood essential for the neonate's health and development. During the prepartum colostrum secretion, the newborn intestine undergoes transient alterations in the intestinal barrier, primarily regulating immunoglobulin absorption. Accordingly, the immunity transfer can be delineated in two stages: the initial stage, which occurs on the maternal side (colostrogenesis serves as the primary immunoglobulin source), and the subsequent stage, which appears on the newborn side (the gut closure). The interval between the two stages is of great consequence, influencing the extent of immunity absorption and, thus, the newborn's health outcomes. The dual-phase (maternal-neonatal) process of immunity transport intersects with numerous factors, including cellular receptors such as the neonatal Fc receptor (FcRn), endocrine factors, physiological cellular phenomena (such as the blood-milk barrier), and environmental circumstances. However, no previous discussions have investigated the immunity transfer to neonatal health, nor have they discussed both sides. This gap highlights the necessity for further investigation into the time-dependent process, which can be described as a race against time to transfer adequate immunity (in quantity and quality) to neonates. Accordingly, the review encompasses a comprehensive analysis of immunological studies, from their foundational stages to the latest molecular research conducted on various mammalian species. This review aims to discern patterns and draw comparisons that advance our understanding of the complex interplay between colostral immunity transfers from diverse view points, including veterinary science and immunology.

Drug safety is a paramount concern in the field of drug development, with researchers increasingly focusing on the bidirectional regulation of gut microbiota in this context. The gut microbiota plays a crucial role in maintaining drug safety. It can influence drug transport processes in the body through various mechanisms, thereby modulating their efficacy and toxicity. The main mechanisms include: (1) The gut microbiota directly interacts with drugs, altering their chemical structure to reduce toxicity and enhance efficacy, thereby impacting drug transport mechanisms, drugs can also change the structure and abundance of gut bacteria; (2) bidirectional regulation of intestinal barrier permeability by gut microbiota, promoting the absorption of nontoxic drugs and inhibiting the absorption of toxic components; (3) bidirectional regulation of the expression and activity of transport proteins by gut microbiota, selectively promoting the absorption of effective components or inhibiting the absorption of toxic components. This bidirectional regulatory role enables the gut microbiota to play a key role in maintaining drug balance in the body and reducing adverse reactions. Understanding these regulatory mechanisms sheds light on novel approaches to minimize toxic side effects, enhance drug efficacy, and ultimately improve drug safety. This review systematically examines the bidirectional regulation of gut microbiota in drug transportation from the aforementioned aspects, emphasizing their significance in ensuring drug safety. Furthermore, it offers a prospective outlook from the standpoint of enhancing therapeutic efficacy and reducing drug toxicity, underscoring the importance of further exploration in this research domain. It aims to provide more effective strategies for drug development and treatment.

The tight junction (TJ), a type of cell-cell junction, regulates the permeability of solutes across epithelial and endothelial cellular sheets and is believed to maintain cell polarity. However, recent studies have provided conflicting views on the roles of TJs in epithelial polarity. Membrane proteins, including occludin, claudin, and the junction adhesion molecule, have been identified as TJ components. TJs are predominantly found at the stratum granulosum and stratum corneum. Although it remains unclear whether the disruption of TJs is the cause or consequence of certain dental diseases, evidence suggests that TJ dysfunction may be a crucial factor in gingival epithelial barrier impairment and the progression of oral diseases. Bacterial infection is among the most specific factors we found that may contribute to the breakdown of the epithelial barrier formed by TJs in dental diseases. Bacteria and their products may weaken the epithelial barrier by directly destroying intercellular junctions or altering the expression of junctional proteins. Additionally, they may induce the production of inflammatory cytokines, which could lead to the downregulation of TJ proteins and, consequently, impair the epithelial barrier. This review introduces a novel perspective by exploring, for the first time, the role of TJs dysfunction in the breakdown of the oral epithelial barrier and its potential link to the progression of dental diseases such as gingivitis, periodontitis, Sjӧgren syndrome, and oral squamous cell carcinoma.

Epithelial cells (ECs) provide the first line of defense against microbial threats and environmental challenges. They participate in the host's immune responses via the expression and secretion of various immune-related molecules such as cytokines and chemokines, as well as interaction with immune cells. A growing body of evidence suggests that the dysregulated function of ECs can be involved in the pathophysiology of a broad range of infectious, autoimmune, and inflammatory diseases, including inflammatory bowel disease (IBD), asthma, multiple sclerosis, and rheumatoid arthritis. To maintain a substantial immunoregulatory function of ECs, precise expression of different molecules and their regulatory effects are indispensable. MicroRNAs (miRNAs, miRs) are small non-coding RNAs that regulate gene expression commonly at post-transcriptional level through degradation of target messenger RNAs (mRNAs) or suppression of protein translation. MiRNAs implicate as critical regulators in many cellular processes, including apoptosis, growth, differentiation, and immune response. Due to the crucial roles of miRNAs in such a vast range of biological processes, they have become the spotlight of biological research for more than two decades, but we are still at the beginning stages of the use of miRNA-based therapies in the improvement of human health. Hence, in the present paper, attempts are made to provide a comprehensive overview with regard to the roles of miRNAs in the immunoregulatory functions of ECs. A better understanding of the molecular mechanisms through which immunoregulatory properties of ECs are manifested, could aid the development of efficient strategies to prevent and treat multiple human diseases.

A hallmark change during carcinogenesis is disruption or dysregulation of cell-cell junctions. It enables a transformed cell to adopt mesenchymal phenotype and acquire higher potential to migrate and invade. This ultimately leads to cancer metastasis. During this process, junctional proteins undergo remarkable changes in terms of their expressional pattern, localization, and activity. De-localized junctional proteins may adopt atypical roles which might act to either suppress tumorigenesis or facilitate cancer development, depending on several factors. In this chapter, the authors attempt to know the expression pattern of junctional proteins in different types of cancer, understand its significance, and gather knowledge about the mechanisms by which they regulate tumorigenesis and cancer development.

In addition to their adhesive properties, cell adhesion molecules such as claudins (CLDNs) exhibit signaling ability to organize diverse cellular events. Although the CLDN-adhesion signaling stimulates or inhibits cancer progression, the underlying mechanism remains poorly established. Here, we verified whether and how CLDN10 promotes intracellular signals and malignant phenotypes in clear cell renal cell carcinoma (ccRCC).

We developed a novel monoclonal antibody that specifically recognizes CLDN10. By immunohistochemistry using this antibody, the clinicopathological significance of aberrant CLDN10 expression in 165 ccRCC patients was determined. We next generated the ccRCC cells (786-O, ACHN, and OS-RC-2) expressing CLDN10, and compared their phenotypes with those of control cells. Immunoprecipitation-mass spectrometry was used to identify a CLDN10-interacting protein, followed by evaluation of its association with CLDN10 and loss-of-functions in ccRCC cells.

High CLDN10 expression predicted poor outcome in ccRCC patients and represented an independent prognostic marker for cancer-specific survival. Cell surface CLDN10 promoted cell viability, proliferation, and migration of ccRCC cells, as well as their tumor growth. CLDN10 also activated mTOR signaling and expression of downstream targets, including MYC target genes. Notably, we found that CLDN10 forms a complex with an amino acid transporter, LAT1, and that CLDN10-LAT1 signaling facilitates malignant phenotypes in ccRCC cells. Structural prediction and immunoprecipitation analysis results strongly suggest an interaction between CLDN10-TM1 (transmembrane domain 1) and LAT1-TM4.

We conclude that CLDN10-LAT1 signaling drives ccRCC progression. Taken together with our previous findings on CLDN-Src-family kinases signaling, CLDNs propagate distinct intracellular signals depending on their association with different binding partners.

Cell junctions, including anchoring, occluding and communicating junctions, play an indispensable role in the structural and functional organization of multicellular tissues, including in liver. Specifically, hepatic cell junctions mediate intercellular adhesion and communication between liver cells. The establishment of the hepatic cell junction network is a prerequisite for normal liver functioning. Hepatic cell junctions indeed support liver-specific features and control essential aspects of the hepatic life cycle. This review paper summarizes the role of cell junctions and their components in relation to liver physiology, thereby also discussing their involvement in hepatic dysfunctionality, including liver disease and toxicity.

Better mechanistic understanding of desmosome disruption and acantholysis in Grover's disease (GD) may improve management of this disease. Recent molecular studies highlighted promising pathways to be explored by directly comparing GD and selected features of associated skin diseases. The association between GD and cutaneous keratinocyte carcinomas, the most prevalent non-melanoma skin cancers (NMSC), is not completely characterized. To review the medical literature regarding GD-associated cutaneous keratinocyte cancers, focusing on molecular features, pathophysiological mechanisms, and disease associations, to help guide future research and patient management. GD has been associated with a variety of skin conditions, but its association with skin cancers has been rarely reported. Between 1983 and 2024, only nine scientific papers presented data supporting this association. Interestingly, we found that GD may mimic multiple NMSCs, as few authors reported GD cases misdiagnosed as multiple cutaneous squamous cell carcinomas for more than 4 years or the presence of superficial basal cell carcinoma-like areas associated with focal acantholysis. In conclusion: (a) GD may be an imitator of multiple NMSCs, and (b) the relationship between GD and NMSCs may reveal promising pathways for the mechanistic understanding of desmosome disruption and acantholysis in GD and may even lead to its reclassification as a distinctive syndrome.

Acute lung injury (ALI) is a severe clinical respiratory condition characterized by high rates of mortality and morbidity, for which effective treatments are currently lacking. In this study, lipopolysaccharide (LPS) was used to induce ALI mice, demonstrating the efficacy of tetramethylpyrazine (TMP) in ameliorating ALI. Subsequent we perfored high-throughput sequencing analysis and used Targetscan 8.0 and miRWalk 3.0 databases to predict the interaction between microRNAs and destrin (DSTN), ultimately identifying miR-369-3p as the focus of the investigation. The adenovirus carrying miR-369-3p was administered one week prior to LPS-induced in order to assess its potential efficacy in ameliorating ALI in mice. The findings indicated that the overexpression of miR-369-3p resulted in enhanced lung function, reduced pulmonary edema, inflammation, and permeability in LPS-induced ALI mice, while the suppression of miR-369-3p exacerbated the damage in these mice. Furthermore, the beneficial effects of TMP on LPS-induced ALI were negated by the downregulation of miR-369-3p. The results of our study demonstrate that TMP mitigates LPS-induced ALI through upregulation of miR-369-3p. Consequently, the findings of this study advocate for the clinical utilization of TMP in ALI treatment, with miR-369-3p emerging as a promising target for future ALI interventions.

Low temperature is a common stress source for the poultry industry in the north of China. However, the low energy consuming and economical way to reduce the negative effects from cold stress is still limited. Therefore, the aim of this study was to investigate the effect of rutin on intestinal barrier in mice under low temperature. The cold stress model was established at 4°C for 3 h each day and the experiment lasted for 21 days. Forty Balb/c mice were randomly divided into four treatments: CON, normal temperature with the basal diet; RUT, normal temperature with the basal diet +150 mg/kg body weight (BW) of rutin; CS, mice under cold stress with basal diet; CR, 150 mg/kg of BW rutin under cold stress. Rutin supplementation significantly increased the ileum villus-to-crypt ratio compared with these non-supplemented treatments. Rutin attenuated the hypothermia induced morphological damage in the ileum. In addition, rutin improved the antioxidant capacity of mice under cold stress. Rutin supplementation significantly increased the trypsin activity and inhibited the lipase in cold stressed mice. Rutin supplementation significantly inhibited the production of inflammatory factors induced by cold stress. Rutin induced the inhibition of TLR4 and NF-кB, thereby reducing the expression of inflammation-related genes. In addition, rutin improved the reduction of the intestinal claudin-1 and occludin expression in those mice in the cold stress (P < .05) and improved the intestinal ZO-1 expression in cold stressed mice. Finally, rutin alleviated the dysregulation of intestinal microflora in the mice under cold stress.

Chronic rhinosinusitis with nasal polyp (CRSwNP) is a typical type 2 inflammation involving interleukin (IL)-4 and IL-13. Dupilumab is a fully human monoclonal antibody targeting IL-4 receptor α subunit, thereby blocking signaling by both cytokines. Our hypothesis was that IL-4 and IL-13, by inducing a severe epithelial dysregulation, are involved in CRSwNP pathogenesis. This study aimed to evaluate the in vitro direct effect of IL-4, IL-13, and dupilumab on nasal epithelial functions.

Nasal polyps and control mucosa from 28 patients, as well as human nasal epithelial cells (HNEC) from 35 patients with CRSwNP were used. Three major epithelial functions were investigated: the epithelial barrier function (characterized by transepithelial electrical resistance measurements and tight junction protein expression), the ciliary motion (characterized by the ciliary beating efficiency index), and wound healing (characterized by the wound repair rate) under various stimulations (IL-4, IL-13, and dupilumab). The main outcome was a significant change in epithelial functions following exposure to IL-4, IL-13, and dupilumab for 48 h in the basal media.

IL-4 (1, 10, and 100 ng/mL) but not IL-13 induced a significant decrease in occludin and zonula-occludens protein expression, ciliary beating efficiency, and wound repair rate in HNEC. Dupilumab (0.04 mg/mL) had no effect on HNEC and specifically restored all epithelial functions altered when cells were exposed to a 48-h IL-4 stimulation.

Dupilumab, in vitro, restored epithelial integrity by counteracting the effect of IL-4 on the epithelial barrier (increased epithelial permeability, decreased ciliary beating efficiency, and decreased wound repair rate).

Gut barrier is not only part of the digestive organ but also an important immunological organ for the hosts. The disruption of gut barrier can lead to various diseases such as obesity and colitis. In recent years, traditional Chinese medicine (TCM) has gained much attention for its rich clinical experiences enriched in thousands of years. After orally taken, TCM can interplay with gut microbiota. On one hand, TCM can modulate the composition and function of gut microbiota. On the other hand, gut microbiota can transform TCM compounds. The gut microbiota metabolites produced during the actions of these interplays exert noticeable pharmacological effects on the host especially gut barrier. Recently, a large number of studies have investigated the repairing and fortifying effects of TCM on gut barriers from the perspective of gut microbiota and its metabolites. However, no review has summarized the mechanism behand this beneficiary effects of TCM. In this review, we first briefly introduce the unique structure and specific function of gut barrier. Then, we summarize the interactions and relationship amidst gut microbiota, gut microbiota metabolites and TCM. Further, we summarize the regulative effects and mechanisms of TCM on gut barrier including physical barrier, chemical barrier, immunological barrier, and microbial barrier. At last, we discuss the effects of TCM on diseases that are associated gut barrier destruction such as ulcerative colitis and type 2 diabetes. Our review can provide insights into TCM, gut barrier and gut microbiota.

Microvascular destabilization is the primary cause of the inner blood-retinal barrier (iBRB) breakdown and increased vascular leakage in diabetic retinopathy (DR). Microvascular destabilization results from the combinational effects of increased levels of growth factors and cytokines, involvement of inflammation, and the changed cell-to-cell interactions, especially the loss of endothelial cells and pericytes, due to hyperglycemia and hypoxia. As the manifestation of microvascular destabilization, the fluid transports via paracellular and transcellular routes increase due to the disruption of endothelial intercellular junctional complexes and/or the altered caveolar transcellular transport across the retinal vascular endothelium. With diabetes progression, the functional and the structural changes of the iBRB components, including the cellular and noncellular components, further facilitate and aggravate microvascular destabilization, resulting in macular edema, the neuroretinal damage and the dysfunction of retinal inner neurovascular unit (iNVU). Although there have been considerable recent advances towards a better understanding of the complex cellular and molecular network underlying the microvascular destabilization, some still remain to be fully elucidated. Recent data indicate that targeting the intricate signaling pathways may allow to against the microvascular destabilization. Therefore, efforts have been made to better clarify the cellular and molecular mechanisms that are involved in the microvascular destabilization in DR. In this review, we discuss: (1) the brief introduction of DR and microvascular destabilization; (2) the cellular and molecular components of iBRB and iNVU, and the breakdown of iBRB; (3) the matrix and cell-to-cell contacts to maintain microvascular stabilization, including the endothelial glycocalyx, basement membrane, and various cell-cell interactions; (4) the molecular mechanisms mediated cell-cell contacts and vascular cell death; (5) the altered cytokines and signaling pathways as well as the intricate network of the cytokines involved in microvascular destabilization. This comprehensive review aimed to provide the insights for microvascular destabilization by targeting the key molecules or specific iBRB cells, thus restoring the function and structure of iBRB and iNVU, to treat DR.

The co-culture of two adult human colorectal cancer cell lines, Caco-2 and HT29, on Transwell is commonly used as an in vitro gut mimic, yet the translatability of insights from such a system to adult human physiological contexts is not fully characterized. Here, we used single-cell RNA sequencing on the co-culture to obtain a detailed survey of cell type heterogeneity in the system and conducted a holistic comparison with human physiology. We identified the intestinal stem cell-, transit amplifying-, enterocyte-, goblet cell-, and enteroendocrine-like cells in the system. In general, the co-culture was fetal intestine-like, with less variety of gene expression compared to the adult human gut. Transporters for major types of nutrients were found in the majority of the enterocytes-like cells in the system. TLR 4 was not expressed in the sample, indicating that the co-culture model is incapable of mimicking the innate immune aspect of the human epithelium.

Successful biochemical reactions in organisms necessitate compartmentalization of the requisite components. Glandular trichomes (GTs) act as compartments for the synthesis and storage of specialized compounds. These compounds not only are crucial for the survival of plants under biotic and abiotic stresses but also have medical and commercial value for humans. However, the mechanisms underlying compartmentalization remain unclear. Here we identified a novel structure that is indispensable for the establishment of compartments in cucumber GTs. Silica, a specialized compound, is deposited on the GTs and is visible on the surface of the fruit as a white powder, known as bloom. This deposition provides resistance against pathogens and prevents water loss from the fruits1. Using the cucumber bloomless mutant2, we discovered that a lignin-based cell wall structure in GTs, named 'neck strip', achieves compartmentalization by acting as an extracellular barrier crucial for the silica polymerization. This structure is present in the GTs of diverse plant species. Our findings will enhance the understanding of the biosynthesis of unique compounds in trichomes and provide a basis for improving the production of compounds beneficial to humans.

Systemic inflammation in chronic kidney disease (CKD) is associated (as a cause or effect) with intestinal barrier dysfunction and increased gut permeability, with mechanisms not yet fully understood. This study investigated different parameters of the intestinal barrier in CKD patients, especially tight junction (TJ) proteins and their possible association with systemic endotoxemia and inflammation.

Thirty-three patients with stage I-IV CKD (n = 17) or end-stage kidney disease (ESKD) (n = 16) and 11 healthy controls underwent duodenal biopsy. Samples were examined histologically, the presence of CD3+ T-lymphocytes and the expression of occludin and claudin-1 in the intestinal epithelium was evaluated by means of immunohistochemistry, circulating endotoxin concentrations were determined by means of ELISA and the concentrations of the cytokines IL-1β, IL-6, IL-8, IL-10 and TNF-α in serum were measured using flow cytometry.

Patients with stage I-IV CKD or ESKD had significantly higher serum endotoxin, IL-6, IL-8 and IL-10 levels compared to controls. Intestinal occludin and claudin-1 were significantly decreased, and their expression was inversely correlated with systemic endotoxemia. Regarding occludin, a specific expression pattern was observed, with a gradually increasing loss of its expression from the crypt to the tip of the villi.

The expression of occludin and claudin-1 in enterocytes is significantly reduced in patients with CKD, contributing to systemic endotoxemia and inflammatory responses in these patients.

Riemerella anatipestifer (RA) is an important pathogen of waterfowl, with multiple serotypes and a lack of cross-protection between each serotype, which leads to the continued widespread in the world and causing significant economic losses to the duck industry. Thus, prevention and inhibition of RA infection are of great concern. Previous research has established that Lactobacillus plantarum supernatant (LPS) can prevents the pathogenic bacteria infection. However, LPS whether inhibits RA and underlying mechanisms have not yet been clarified. In this study, we investigated the direct and indirect effects of LPS-ZG7 against RA infection in Muscovy ducks. The results demonstrated that LPS-ZG7 prevented RA growth in the presence of pH-neutralized, and the inhibition was relatively stable and unaffected by heat, acid-base and ultraviolet light (UV). Following flow cytometry data found that LPS-ZG7 increased RA membrane permeability and leakage of intracellular molecules. And scanning electron microscopy revealed LPS-ZG7 damaged the RA membrane integrity and leading to RA death. Furthermore, quantitative real time polymerase chain reaction (qPCR) analysis represented that LPS-ZG7 upregulated mucosal tight junction proteins occludin, claudin-1, and Zo-1 in Muscovy ducks, and increasing mucosal transport channels SGLT-1, PepT1, AQP2, AQP3, and AQP10 in duodenum, jejunum, and colon, then decreased the intestinal permeability and intestinal barrier disruption which were caused from RA. From the data, it is apparent that LPS-ZG7 enhanced intestinal mucosal integrity by rising villus height, villus height-to-crypt depth ratio and lower crypt depth. LPS-ZG7 significantly decreased intestinal epithelia cells apoptosis caused by RA invasion, and enhanced intestinal permeability and contribute to barrier dysfunction, ultimately improving intestinal health of host, indirectly leading to reduce diarrhea rate and mortality caused by RA. Overall, this study strengthens the idea that LPS-ZG7 directly inhibited the RA growth by increased RA membrane permeability and damaged the RA membrane integrity, and then indirectly enhanced intestinal mucosal integrity, improved intestinal health of host and mediated intestinal antimicrobial defense.

Lung infection by influenza A virus (IAV) is a major cause of global mortality from lung injury, a disease defined by widespread dysfunction of the lung's air-blood barrier. Endocytosis of IAV virions by the alveolar epithelium - the cells that determine barrier function - is central to barrier loss mechanisms. Here, we address the current understanding of the mechanistic steps that lead to endocytosis in the alveolar epithelium, with an eye to how the unique structure of lung alveoli shapes endocytic mechanisms. We highlight where future studies of alveolar interactions with IAV virions may lead to new therapeutic approaches for IAV-induced lung injury.

Although intestinal microbiota alterations (dysbiosis) have been described in heart failure (HF) patients, the possible mechanisms of intestinal barrier dysfunction leading to endotoxemia and systemic inflammation are not fully understood. In this study, we investigated the expression of the intestinal tight junction (TJ) proteins occludin and claudin-1 in patients with HF with reduced (HFrEF) or preserved ejection fraction (HFpEF) and their possible association with systemic endotoxemia and inflammation. Ten healthy controls and twenty-eight patients with HF (HFrEF (n = 14), HFpEF (n = 14)) underwent duodenal biopsy. Histological parameters were recorded, intraepithelial CD3+ T-cells and the expression of occludin and claudin-1 in enterocytes were examined using immunohistochemistry, circulating endotoxin concentrations were determined using ELISA, and concentrations of cytokines were determined using flow cytometry. Patients with HFrEF or HFpEF had significantly higher serum endotoxin concentrations (p < 0.001), a significantly decreased intestinal occludin and claudin-1 expression (in HfrEF p < 0.01 for occludin, p < 0.05 for claudin-1, in HfpEF p < 0.01 occludin and claudin-1), and significantly increased serum concentrations of IL-6, IL-8, and IL-10 (for IL-6 and IL-10, p < 0.05 for HFrEF and p < 0.001 for HFpEF; and for IL-8, p < 0.05 for both groups) compared to controls. Occludin and claudin-1 expression inversely correlated with systemic endotoxemia (p < 0.05 and p < 0.01, respectively). Heart failure, regardless of the type of ejection fraction, results in a significant decrease in enterocytic occludin and claudin-1 expression, which may represent an important cellular mechanism for the intestinal barrier dysfunction causing systemic endotoxemia and inflammatory response.

Tight junctions (TJs) are cell-cell interactions that localize at the most apical portion of epithelial/endothelial cells. One of the predominant functions of TJs is to regulate material transport through paracellular pathway, which serves as a selective barrier. In recent years, the expression and function of TJs in salivary glands has attracted great interest. The characteristics of multiple salivary gland TJ proteins have been identified. During salivation, the activation of muscarinic acetylcholine receptor and transient receptor potential vanilloid subtype 1, as well as other stimuli, promote the opening of acinar TJs by inducing internalization of TJs, thereby contributing to increased paracellular permeability. Besides, endothelial TJs are also redistributed with leakage of blood vessels in cholinergic-stimulated submandibular glands. Furthermore, under pathological conditions, such as Sjögren's syndrome, diabetes mellitus, immunoglobulin G4-related sialadenitis, and autotransplantation, the integrity and barrier function of TJ complex are impaired and may contribute to hyposalivation. Moreover, in submandibular glands of Sjögren's syndrome mouse model and patients, the endothelial barrier is disrupted and involved in hyposecretion and lymphocytic infiltration. These findings enrich our understanding of the secretory mechanisms that link the importance of epithelial and endothelial TJ functions to salivation under both physiological and pathophysiological conditions.

Claudin-4 is a key component of tight junctions, which play an important role in the formation of the epidermal barrier by forming a circumferential network in the granular layer that serves as a gatekeeper of the paracellular pathway. The aim of this study is to illustrate claudin-4 immunohistochemical staining patterns of different blistering disorders. We collected 35 cases, including two Hailey-Hailey disease, one Darier disease, three Grover disease, one acantholytic acanthoma, two warty dyskeratoma, 11 pemphigus vulgaris (PV) including six mucosal PV, and two pemphigus foliaceus. For comparison, we included five cases of normal skin, five eczema, and three bullous pemphigoid cases. Claudin-4 demonstrated weak-to-moderate expression in keratinocytes located in the stratum granulosum, keratinocytes surrounding hair follicles, and adnexal glands. Further, claudin-4 exhibited moderate-to-strong membranous staining in disrupted keratinocytes surrounding and within the acantholytic and bullous areas in 16/22 of the acantholytic cases (not seen in the six cases of mucosal PV) and all three bullous pemphigoids. This finding suggests that claudin-4 is upregulated in these conditions, which may be a compensatory response to the disrupted barrier function. This finding could shed light on the molecular mechanisms underlying disrupted barrier function in blistering disorders, independent of the specific underlying disease mechanism.

Inflammatory bowel diseases (IBD) are a group of chronic relapsing gastrointestinal inflammatory diseases with significant global incidence. Although the pathomechanism of IBD has been extensively investigated, several aspects of its pathogenesis remain unclear. Long non-coding RNAs (lncRNAs) are transcripts with more than 200 nucleotides in length that have potential protein-coding functions. LncRNAs play important roles in biological processes such as epigenetic modification, transcriptional regulation and post-transcriptional regulation. In this review, we summarize recent advances in research on IBD-related lncRNAs from the perspective of the overall intestinal microenvironment, as well as their potential roles as immune regulators, diagnostic biomarkers and therapeutic targets or agents for IBD.

Gintonin, newly extracted from ginseng, is a glycoprotein that acts as an exogenous lysophosphatidic acid (LPA) receptor ligand. This study aimed to demonstrate the in vivo preventive effects of gintonin on gastric damage. ICR mice were randomly assigned to five groups: a normal group (received saline, 0.1 mL/10 g, p.o.); a control group (administered 0.3 M HCl/ethanol, 0.1 mL/10 g, p.o.) or indomethacin (30 mg/kg, p.o.); gintonin at two different doses (50 mg/kg or 100 mg/kg, p.o.) with either 0.3 M HCl/ethanol or indomethacin; and a positive control (Ranitidine, 40 mg/kg, p.o.). After gastric ulcer induction, the gastric tissue was examined to calculate the ulcer index. The expression of gastric damage markers, such as tumor necrosis factor (TNF)-α, cyclooxygenase 2 (COX-2), and LPA2 and LPA5 receptors, were measured by Western blotting. Interleukin-6 (IL-6) and prostaglandin E2 (PGE2) levels were measured by enzyme-linked immunosorbent assay. The platelet endothelial cell adhesion molecule (PECAM-1), Evans blue, and occludin levels in gastric tissues were measured using immunofluorescence analysis. Both HCl/ethanol- and indomethacin-induced gastric ulcers showed increased TNF-α, IL-6, Evans blue permeation, and PECAM-1, and decreased COX-2, PGE2, occludin, and LPA5 receptor expression levels. However, oral administration of gintonin alleviated the gastric ulcer index induced by HCl/ethanol and indomethacin in a dose-dependent manner. Gintonin suppressed TNF-α and IL-6 expression, but increased COX-2 expression and PGE2 levels in mouse gastric tissues. Gintonin intake also increased LPA5 receptor expression in mouse gastric tissues. These results indicate that gintonin can play a role in gastric protection against gastric damage induced by HCl/ethanol or indomethacin.

Brain aging and cognitive decline are aspects of growing old. Age-related cognitive impairment entails the early stages of cognitive decline, and is extremely common, affecting millions of older people. Investigation into early cognitive decline as a treatable condition is relevant to a wide range of cognitive impairment conditions, since mild age-related neuropathology increases risk for more severe neuropathology and dementia associated with Alzheimer's Disease. Recent studies suggest that the naturally occurring peptide GHK (glycyl-L-histidyl-L-lysine) in its Cu-bound form, has the potential to treat cognitive decline associated with aging. In order to test this concept, male and female C57BL/6 mice, 20 months of age, were given intranasal GHK-Cu, 15 mg/kg daily, for two months. Results showed that mice treated with intranasal GHK-Cu had an enhanced level of cognitive performance in spatial memory and learning navigation tasks, and expressed decreased neuroinflammatory and axonal damage markers compared to mice treated with intranasal saline. These observations suggest that GHK-Cu can enhance resilience to brain aging, and has translational implications for further testing in both preclinical and clinical studies using an atomizer device for intranasal delivery.

The oleoresin myrrh has been used for centuries as an anti-inflammatory remedy for a variety of diseases and is said to have a protective effect on the intestinal epithelium. An intact epithelial barrier function is the prerequisite for a healthy gut. Inflammatory and infectious diseases of the intestine, in particular, lead to barrier impairment resulting in leak-flux diarrhea and mucosal immune responses. Therefore, the aim of the present study was to investigate the protective effect of myrrh in an experimental inflammatory situation, namely, under the influence of IL-13, one of the key cytokines in ulcerative colitis. We used human intestinal epithelial HT-29/B6 cell monolayers for functional and molecular assessment of the epithelial barrier under IL-13 and myrrh treatment. IL-13 induced a loss in barrier function that was fully restored with myrrh treatment, as shown by transepithelial electrical resistance measurements. The molecular correlate of the IL-13-mediated barrier dysfunction could be assigned to an upregulation of the channel-forming tight junction (TJ) protein claudin-2 and to a subcellular redistribution of the TJ protein tricellulin, loosening the sealing of tricellular TJs. Moreover, IL-13 exposure leads to an increase in the number of apoptotic cells, contributing to the leak pathway of barrier dysfunction. Myrrh protected against changes in TJ deregulation and decreased the elevated apoptotic ratio under IL-13. The protective effects are mediated through the inhibition of the STAT3 and STAT6 pathway. In conclusion, our results demonstrate that myrrh exhibits antagonizing effects against IL-13-induced barrier impairment in a human intestinal cell model. These data suggest the use of myrrh as a promising option in the treatment of inflammatory bowel disease.

Microplastics (MPs) are widely distributed in the global environment, entering and accumulating in organisms in various ways and posing health threats. MPs can damage intestine; however, the mechanism by which MPs cause intestinal damage in rats is unclear. Here, rats were exposed to 50 nm PS-NPs or 5 μm PS-MPs for 4 weeks to evaluate the possible effects on intestinal barrier function and exosomal miRNAs expressions. The results showed that PS-NPs or PS-MPs disrupted the gut microbiota and affected gut barrier function at the biological level. In addition, PS-NPs and PS-MPs altered the composition of exosomal miRNAs in the intestinal and serum. Both PS-NPs and PS-MPs decreased the expression of miR-126a-3p in the intestinal and serum exosomes, which is an important signalling molecule involved in MPs induced gut barrier function disorder. More importantly, both in vitro and in vivo experiments indicated that miR-126a-3p was closely related to oxidative damage of intestinal cells through the PI3K-Akt pathway and eventually promote cell apoptosis by regulating the target gene of PIK3R2. Our study suggested that PS-NPs and PS-MPs could affect rat intestinal barrier function through an exosomal miRNA mediated pathway.

Extracellular vesicles (EVs) play an active role in regulating different physiological events, however, endocrine control of EVs cargo contents remain poorly understood. In this study, we aimed to isolate EVs from the porcine oviductal epithelial cells (POECs) that were primed with steroid hormones including estradiol (E2) and progesterone (P4), mimicking the in vivo conditions of the reproductive cycle and studied their effects on in vitro produced embryonic development. For this purpose, POECs were treated either with 0 concentration (control) or two different combinations of E2 and P4 including 50 pg/mL E2 + 0.5 ng/mL P4 (group H1), and 10 pg/mL E2 + 35 ng/mL P4 (group H2). Embryos were prepared after in vitro maturation either by parthenogenetic activation or somatic cell nuclear transfer (SCNT) technique. Treating parthenogenetic embryo with EVs, led a significantly higher rate of the blastocyst formation in the group supplemented with each EVs, compared to the control group. In addition, TUNEL assay and gene expression level analysis revealed that apoptosis was significantly reduced in the H2 EVs group. Furthermore, EVs from hormone-primed POECs improved the formation rate of porcine SCNT embryos compared to the control group. While in each EVs supplemented group (control EVs, H1 EVs, H2 EVs), the expression of cell reprogramming-related genes in cloned embryos showed a tendency of increase, the effect was stronger in H1 EVs and H2 EVs. In conclusion, EVs derived from POECs cultured in hormonal conditions simulating the in vivo environment had a positive effect on porcine blastocysts formation, which will likely facilitate in the production of cloned embryos.

Several types of gluten-related disorders are known, in which the common starting point is gluten-induced zonulin release. Zonulin results in varying degrees of increased permeability in certain gluten-related disorders but is largely responsible for the development of further pathogenic processes and symptoms. Therefore, it is important to know the barrier-modulating role of individual nutritional components and to what extent the antioxidant substance supports the protection of gliadin-induced membrane damage with its radical scavenging capacity. We investigated the pH dependence of the gliadin-anthocyanin interaction using UV photometry, during which a concentration-dependent interaction was observed at pH 6.8. The barrier modulatory effect of the anthocyanin-rich sour cherry extract (AC) was analyzed on Caco-2 cell culture with pepsin-trypsin-resistant gliadin (PT-gliadin) exposure by TEER measurement, zonula occludens-1 (ZO-1), and Occludin immunohistochemistry. In addition to the TEER-reducing and TJ-rearranging effects of PT-gliadin, NF-κB activation, an increase in cytokine (TNF-α, IFN-γ, and IL-8) release, and mitochondrial ROS levels were observed. We confirmed the anti-inflammatory, stabilizing, and restoring roles of AC extract during gliadin treatment on the Caco-2 monolayer. The extract was able to significantly reduce cytokine and ROS levels despite the known interaction of the main components of the extract with PT-gliadin.

Protein therapeutics have guided a transformation in disease treatment for various clinical conditions. They have been successful in numerous applications, but administration of protein therapeutics has been limited to parenteral routes which can decrease patient compliance as they are invasive and painful. In recent years, the synergistic relationship of novel biomaterials with modern protein therapeutics has been crucial in the treatment of diseases that were once thought of as incurable. This has guided the development of a variety of alternative administration routes, but the oral delivery of therapeutics remains one of the most desirable due to its ease of administration. This review addresses important aspects of micellar structures prepared by self-assembled processes with applications for oral delivery. These two characteristics have not been placed together in previous literature within the field. Therefore, we describe the barriers for delivery of protein therapeutics, and we concentrate in the oral/transmucosal pathway where drug carriers must overcome several chemical, physical, and biological barriers to achieve a successful therapeutic effect. We critically discuss recent research on biomaterials systems for delivering such therapeutics with an emphasis on self-assembled synthetic block copolymers. Polymerization methods and nanoparticle preparation techniques are similarly analyzed as well as relevant work in this area. Based on our own and others' research, we analyze the use of block copolymers as therapeutic carriers and their promise in treating a variety of diseases, with emphasis on self-assembled micelles for the next generation of oral protein therapeutic systems.

Mastitis occurs frequently in breastfeeding women and not only affects the women's health but also hinders breastfeeding. Maslinic acid is a type of pentacyclic triterpenoid widely found in olives that has good anti-inflammatory activity. This study aims to discuss the protective function of maslinic acid against mastitis and its underlying mechanism. For this, mice models of mastitis were established using lipopolysaccharide (LPS). The results revealed that maslinic acid reduced the pathological lesions in the mammary gland. In addition, it reduced the generation of pro-inflammatory factors and enzymes (IL-6, IL-1β, TNF-α, iNOS, and COX2) in both mice mammary tissue and mammary epithelial cells. The high-throughput 16S rDNA sequencing of intestinal flora showed that in mice with mastitis, maslinic acid treatment altered β-diversity and regulated microbial structure by increasing the abundance of probiotics such as Enterobacteriaceae and downregulating harmful bacteria such as Streptococcaceae. In addition, maslinic acid protected the blood-milk barrier by maintaining tight-junction protein expression. Furthermore, maslinic acid downregulated mammary inflammation by inhibiting the activation of NLRP3 inflammasome, AKT/NF-κB, and MAPK signaling pathways. Thus, in a mice model of LPS-induced mastitis, maslinic acid can inhibit the inflammatory response, protect the blood-milk barrier, and regulate the constitution of intestinal flora.

Airway diseases can disrupt tight junction proteins, compromising the epithelial barrier and making it more permeable to pathogens. In people with pulmonary disease who are prone to infection with Pseudomonas aeruginosa, pro-inflammatory leukotrienes are increased and anti-inflammatory lipoxins are decreased. Upregulation of lipoxins is effective in counteracting inflammation and infection. However, whether combining a lipoxin receptor agonist with a specific leukotriene A4 hydrolase (LTA4H) inhibitor could enhance these protective effects has not to our knowledge been investigated. Therefore, we explored the effect of lipoxin receptor agonist BML-111 and JNJ26993135 a specific LTA4H inhibitor that prevents the production of pro-inflammatory LTB4 on tight junction proteins disrupted by P. aeruginosa filtrate (PAF) in human airway epithelial cell lines H441 and 16HBE-14o. Pre-treatment with BML-111 prevented an increase in epithelial permeability induced by PAF and conserved ZO-1 and claudin-1 at the cell junctions. JNJ26993135 similarly prevented the increased permeability induced by PAF, restored ZO-1 and E-cadherin and reduced IL-8 but not IL-6. Cells pre-treated with BML-111 plus JNJ26993135 restored TEER and permeability, ZO-1 and claudin-1 to the cell junctions. Taken together, these data indicate that the combination of a lipoxin receptor agonist with a LTA4H inhibitor could provide a more potent therapy.

Cold regions have long autumn and winter seasons and low ambient temperatures. When pigs are unable to adjust to the cold, oxidative damage and inflammation may develop. However, the differences between cold and non-cold adaptation regarding glucose and lipid metabolism, gut microbiota and colonic mucosal immunological features in pigs are unknown. This study revealed the glucose and lipid metabolic responses and the dual role of gut microbiota in pigs during cold and non-cold adaptation. Moreover, the regulatory effects of dietary glucose supplements on glucose and lipid metabolism and the colonic mucosal barrier were evaluated in cold-exposed pigs.

Cold and non-cold-adapted models were established by Min and Yorkshire pigs. Our results exhibited that cold exposure induced glucose overconsumption in non-cold-adapted pig models (Yorkshire pigs), decreasing plasma glucose concentrations. In this case, cold exposure enhanced the ATGL and CPT-1α expression to promote liver lipolysis and fatty acid oxidation. Meanwhile, the two probiotics (Collinsella and Bifidobacterium) depletion and the enrichment of two pathogens (Sutterella and Escherichia-Shigella) in colonic microbiota are not conducive to colonic mucosal immunity. However, glucagon-mediated hepatic glycogenolysis in cold-adapted pig models (Min pigs) maintained the stability of glucose homeostasis during cold exposure. It contributed to the gut microbiota (including the enrichment of the Rikenellaceae RC9 gut group, [Eubacterium] coprostanoligenes group and WCHB1-41) that favored cold-adapted metabolism.

The results of both models indicate that the gut microbiota during cold adaptation contributes to the protection of the colonic mucosa. During non-cold adaptation, cold-induced glucose overconsumption promotes thermogenesis through lipolysis, but interferes with the gut microbiome and colonic mucosal immunity. Furthermore, glucagon-mediated hepatic glycogenolysis contributes to glucose homeostasis during cold exposure.

Heatstroke (HS) is a life-threatening injury requiring neurocritical care which could lead to central nervous system dysfunction and severe multiple organ failure syndrome. The cell-cell adhesion and cell permeability are two key factors for characterizing HS. To investigate the process of HS, a biochip-based electrical model was proposed and applied to HS. During the process, the value of TEER is associated with cell permeability and C_I which represents cell-cell adhesion decreases that are consistent with the reduction in cell-cell adhesion and cell permeability characterized by proteins (occludin, VE-Cadherin and ZO-1) and RNA level. The results imply that the model can be used to monitor the biological process and other biomedical applications.

Cell adhesion molecules, including integrins, cadherins, and claudins (CLDNs), are known to activate Src-family kinases (SFKs) that organize a variety of physiological and pathological processes; however, the underlying molecular basis remains unclear. Here, we identify the SFK members that are coupled with the CLDN6-adhesion signaling. Among SFK subtypes, BLK, FGR, HCK, and SRC were highly expressed in F9 cells and concentrated with CLDN6 along cell borders during epithelial differentiation. Immunoprecipitation assay showed that BLK and SRC, but not FGR or HCK, form a complex with CLDN6 via the C-terminal cytoplasmic domain. We also demonstrated, by pull-down assay, that recombinant BLK and SRC proteins directly bind to the C-terminal cytoplasmic domain of CLDN6 (CLDN6C). Unexpectedly, both recombinant SFK proteins recognized the CLDN6C peptide in a phosphotyrosine-independent manner. Furthermore, by comparing phenotypes of F9:Cldn6:Blk-/- and F9:Cldn6:Src-/- cells with those of wild-type F9 and F9:Cldn6 cells, we revealed that BLK and SRC are essential for CLDN6-triggered cellular events, namely epithelial differentiation and the expression of retinoid acid receptor target genes. These results indicate that selective SFK members appear to participate in the CLDN-adhesion signaling.

Cadmium (Cd) is a non-biodegradable widespread environmental pollutant, which can cross the blood-brain barrier (BBB) and cause cerebral toxicity. However, the effect of Cd on the BBB is still unclear. In this study, a total of 80 (1-day-old) Hy-Line white variety chicks (20 chickens/group) were selected and randomly divided into four (4) groups: the control group (Con group) (fed with a basic diet, n = 20), the Cd 35 group (basic diet with 35 mg/kg CdCl₂, n = 20), the Cd 70 group (basic diet with 70 mg/kg CdCl₂, n = 20) and the Cd 140 group (basic diet with 140 mg/kg CdCl₂, n = 20), and fed for 90 days. The pathological changes, factors associated with the BBB, oxidation level and the levels of Wingless-type MMTV integration site family, member 7 A (Wnt7A)/Wnt receptor Frizzled 4 (FZD4)/β-catenin signaling axis-related proteins in brain tissue were detected. Cd exposure induced capillary damage and neuronal swelling, degeneration and loss of neurons. Gene Set Enrichment Analysis (GSEA) showed the weakened Wnt/β-catenin signaling axis. The protein expression of the Wnt7A, FZD4, and β-catenin was decreased by Cd expusure. Inflammation generation and BBB dysfunction were induced by Cd, as manifested by impaired tight junctions (TJs) and adherens junctions (AJs) formation. These findings underscore that Cd induced BBB dysfunction via disturbing Wnt7A/FZD4/β-catenin signaling axis.

Migraine is a complex neurogenic inflammatory disorder. There are strong neuronal, endocrine, and immunologic connections between the brain and gastrointestinal system. Damage to the intestinal barrier is thought to cause systemic immune dysregulation. Zonulin is a protein produced by the small intestine epithelium in humans that regulates intestinal permeability through intracellular tight junctions and is a potential marker for inflammation. Zonulin increases in positive correlation with permeability. In our study, we aimed to research the correlation between serum zonulin levels in the period between attacks in pediatric patients with migraine.

The study included 30 patients with migraine and 24 healthy controls, matched in terms of sex and age. Demographic and clinical characteristics were recorded. Serum zonulin levels were studied with the enzyme-linked immunosorbent assay method.

Patients had a mean of 5.6 ± 3.5 attacks per month. The mean serum zonulin was 5.68 ± 1.21 ng/mL in the migraine group and 5.72 ± 2.1 ng/mL in the control group with no significant difference found (P = 0.084). In the migraine group, no correlations were identified between serum zonulin levels and age, body mass index, pain frequency, pain duration, onset time, visual analog scale score, and presence of gastrointestinal systems apart from nausea-vomiting.

More than 50 proteins were identified to affect the intestinal permeability apart from zonulin. There is a need for prospective studies encompassing the time of attack, but our study is important as it is the first study about zonulin levels in pediatric migraine.

Cell adhesion is indispensable for appropriate tissue architecture and function in multicellular organisms. Besides maintaining tissue integrity, cell adhesion molecules, including tight-junction proteins claudins (CLDNs), exhibit the signaling abilities to control a variety of physiological and pathological processes. However, it is still fragmentary how cell adhesion signaling accesses the nucleus and regulates gene expression.

By generating a number of knockout and rescued human breast cell lines and comparing their phenotypes, we determined whether and how CLDN4 affected breast cancer progression in vitro and in vivo. We also identified by RNA sequencing downstream genes whose expression was altered by CLDN4-adhesion signaling. Additionally, we analyzed by RT-qPCR the CLDN4-regulating genes by using a series of knockout and add-back cell lines. Moreover, by immunohistochemistry and semi-quantification, we verified the clinicopathological significance of CLDN4 and the nuclear receptor LXRβ (liver X receptor β) expression in breast cancer tissues from 187 patients.

We uncovered that the CLDN4-adhesion signaling accelerated breast cancer metabolism and progression via LXRβ. The second extracellular domain and the carboxy-terminal Y197 of CLDN4 were required to activate Src-family kinases (SFKs) and the downstream AKT in breast cancer cells to promote their proliferation. Knockout and rescue experiments revealed that the CLDN4 signaling targets the AKT phosphorylation site S432 in LXRβ, leading to enhanced cell proliferation, migration, and tumor growth, as well as cholesterol homeostasis and fatty acid metabolism, in breast cancer cells. In addition, RT-qPCR analysis showed the CLDN4-regulated genes are classified into at least six groups according to distinct LXRβ- and LXRβS432-dependence. Furthermore, among triple-negative breast cancer subjects, the "CLDN4-high/LXRβ-high" and "CLDN4-low and/or LXRβ-low" groups appeared to exhibit poor outcomes and relatively favorable prognoses, respectively.

The identification of this machinery highlights a link between cell adhesion and transcription factor signalings to promote metabolic and progressive processes of malignant tumors and possibly to coordinate diverse physiological and pathological events.

During lactation, mammary epithelial cells (MECs) on the apical membrane are in contact with lactose in milk, while MECs on the basolateral membrane are in contact with glucose in blood. Both glucose and lactose are sweeteners that are sensed by a sweet taste receptor. Previously, we have shown that lactose exposure on the basolateral membrane, but not the apical membrane, inhibits casein production and phosphorylation of STAT5 in MECs. However, it remains unclear whether MECs have a sweet taste receptor. In this study, we confirmed that the sweet taste receptor subunit T1R3 existed in both the apical and basolateral membranes of MECs. Subsequently, we investigated the influence of apical and basolateral sucralose as a ligand for the sweet taste receptor using a cell culture model. In this model, upper and lower media were separated by the MEC layer with less-permeable tight junctions. The results showed in the absence of glucose, both apical and basolateral sucralose induced phosphorylation of STAT5, which is a positive transcriptional factor for milk production. In contrast, the T1R3 inhibitor basolateral lactisole reducing phosphorylated STAT5 and secreted caseins in the presence of glucose. Furthermore, exposure of the apical membrane to sucralose in the presence of glucose inhibited the phosphorylation of STAT5. Simultaneously, GLUT1 was partially translocated from the basolateral membrane to the cytoplasm in MECs. These results suggest that T1R3 functions as a sweet receptor and is closely involved in casein production in MECs.