The intestinal barrier serves as a boundary between the mucosal immune system in the lamina propria and the external environment of the intestinal lumen, which contains a diverse array of microorganisms and ingested environmental factors, including pathogens, food antigens, toxins, and other foreign substances. This barrier has a central role in regulating the controlled interaction between luminal factors and the intestinal immune system. Disruptions of intestinal epithelial cells, which serve as a physical barrier, or the antimicrobial peptides and mucins they produce, which act as a chemical barrier, can lead to a leaky gut. In this state, the intestinal wall is unable to efficiently separate the intestinal flora and luminal contents from the intestinal immune system. The subsequent activation of the immune system has an important role in the pathogenesis of inflammatory bowel disease, as well as in metabolic dysfunction-associated steatohepatitis, primary sclerosing cholangitis, and colorectal cancer. Dysregulated intestinal barrier integrity has also been described in patients with chronic inflammatory diseases outside the gastrointestinal tract, including rheumatoid arthritis and neurodegenerative disorders. Mechanistic studies of barrier dysfunction have revealed that the subsequent local activation and systemic circulation of activated immune cells and the cytokines they secrete, as well as extracellular vesicles, promote proinflammatory processes within and outside the gastrointestinal tract. In this Review, we summarise these findings and highlight several new therapeutic concepts currently being developed that attempt to control inflammatory processes via direct or indirect modulation of intestinal barrier function.

The destruction of intestinal mucosal mechanical barrier homeostasis caused by excessive apoptosis of intestinal epithelial cells (IECs) is an important reason for the occurrence and development of ulcerative colitis (UC). The increase in mitochondrial membrane permeability caused by the opening of the mitochondrial membrane permeability transition pore (mPTP) is a key link in the initiation of mitochondrial pathway apoptosis. Our previous studies revealed that heat shock transcription factor 2 (HSF2), which is highly expressed in the intestinal mucosa of UC patients, can inhibit the expression of the cytochrome C (Cyto-C)/Caspase-9/Caspase-3 proteins in the mitochondrial pathway of apoptosis, but the regulatory mechanism is unknown. It has been reported that heat shock proteins regulated by heat shock transcription factors are closely related to mPTP opening. Therefore, we hypothesized that HSF2 affects mitochondrial pathway apoptosis in IECs by regulating mPTP opening. In this study, we altered the level of HSF2 in Caco-2 cells by lentivirus transfection to explore the changes in the mitochondrial membrane permeability of Caco-2 cells in an inflammatory environment. Subsequently, the mPTP agonist atractylorhizin (Atr) and inhibitor cyclosporine A (CsA) were used to clarify the regulatory effects of HSF2 on mPTP and the Cyto-C/Caspase-9/Caspase-3 pathways. Our study confirmed for the first time that HSF2 plays a protective role in UC by inhibiting mPTP opening, the increase in mitochondrial membrane permeability and the activation of the mitochondrial-mediated apoptosis pathway in IECs.

This comprehensive review delves into the pivotal role of intestinal epithelial cells in the context of various diseases. It provides an in-depth analysis of the diverse types and functions of these cells, explores the influence of multiple signaling pathways on their differentiation, and elucidates their critical roles in a spectrum of diseases. The significance of the gastrointestinal tract in maintaining overall health is extremely important and cannot be exaggerated. This complex and elongated organ acts as a crucial link between the internal and external environments, making it vulnerable to various harmful influences. Preserving the normal structure and function of the gut is essential for well-being. Intestinal epithelial cells serve as the primary defense mechanism within the gastrointestinal tract and play a crucial role in preventing harmful substances from infiltrating the body. As the main components of the digestive system, they not only participate in the absorption and secretion of nutrients and the maintenance of barrier function but also play a pivotal role in immune defense. Therefore, the health of intestinal epithelial cells is of vital importance for overall health.

Mechanisms by which mucosal regeneration is abrogated in inflammatory bowel disease (IBD) are still under investigation, and a role for an intestinal stem cell (ISC) defect is now emerging. Herein, we report an abnormal ISC death that occurs in Crohn's disease, which exacerbates colitis, limits ISC-dependent mucosal repair, and is controlled through the death factor Transmembrane protein 219 (TMEM219). Large alterations in TMEM219 expression were observed in patients with Crohn's disease, particularly in those with active disease and/or those who were nonresponders to conventional therapy, confirming that TMEM219 signaling is abnormally activated and leads to failure of the mucosal regenerative response. Mechanistic studies revealed a proapoptotic TMEM219-mediated molecular signature in Crohn's disease, which associates with Caspase-8 activation and ISC death. Pharmacological blockade of the IGFBP3/TMEM219 binding/signal with the recombinant protein ecto-TMEM219 restored the self-renewal abilities of miniguts generated from patients with Crohn's disease in vitro and ameliorated DSS-induced and T cell-mediated colitis in vivo, ultimately leading to mucosal healing. Genetic tissue-specific deletion of TMEM219 in ISCs in newly generated TMEM219fl/flLGR5cre mice revived their mucosal regenerative abilities both in vitro and in vivo. Our findings demonstrate that a TMEM219-dependent ISC death exacerbates colitis and that TMEM219 blockade reestablishes intestinal self-renewal properties in IBD.

Inflammatory bowel disease (IBD) is an inflammatory disease of the intestine whose primary pathological presentation is the destruction of the intestinal epithelium. The intestinal epithelium, located between the lumen and lamina propria, transmits luminal microbial signals to the immune cells in the lamina propria, which also modulate the intestinal epithelium. In IBD patients, intestinal epithelial cells (IECs) die dysfunction and the mucosal barrier is disrupted, leading to the recruitment of immune cells and the release of cytokines. In this review, we describe the structure and functions of the intestinal epithelium and mucosal barrier in the physiological state and under IBD conditions, as well as the patterns of epithelial cell death and how immune cells modulate the intestinal epithelium providing a reference for clinical research and drug development of IBD. In addition, according to the targeting of epithelial apoptosis and necroptotic pathways and the regulation of immune cells, we summarized some new methods for the treatment of IBD, such as necroptosis inhibitors, microbiome regulation, which provide potential ideas for the treatment of IBD. This review also describes the potential for integrating AI-driven approaches into innovation in IBD treatments.

Colorectal cancer (CRC) is a significant global health challenge, with rising incidence, particularly among individuals under 50. Increasing evidence highlights the gut microbiota as key contributors to CRC development, with certain oncogenic bacteria influencing cancer initiation, progression, and therapy response. Among these is pks+ Escherichia coli, which produces colibactin, a genotoxic compound that induces DNA damage and leaves a distinct mutational signature in healthy individuals and CRC patients. While research has focused on its genotoxic effects, this review examines the kinetics of colibactin-induced mutations and the epithelial and environmental changes that promote E. coli expansion and colibactin exposure. We also explore the broader role of pks+ E. coli in cancer initiation and progression beyond genotoxicity, and discuss potential therapeutic approaches.

The highly sulfated polysaccharide sea cucumber chondroitin sulfate (SCCS) can alleviate intestinal damage and display strong anti-food-allergic activity. The O-glycopattern levels in colonic mucin are closely related to the its protective effect on function of the intestinal barrier. However, the effect of the SCCS on colonic mucin O-glycan has not been investigated. In this study, ovalbumin (OVA)-sensitized allergic mice and SCCS treatment were used. Mouse colonic mucin O-glycome was released and analyzed through reductive β-elimination combined with PGC-LC-MS. A total of presumptive 20 neutral and 28 acidic O-glycan structures were identified, in which the core 2 type acidic O-glycan structure is predominant in Balb/c female mice. Treatment with OVA and SCCS did not change the numbers of colon mucin O-glycan type, but the expression level of total O-glycosylation was more abundant in the SCCS group mice than in the OVA group (1.8-fold), especially for acidic O-glycans (co-modified by fucose and sulfate groups). Furthermore, supplementation with SCCS reversed most of the O-glycan decreasing trend, which may be associated with a return to healthy levels of gut microbiota. In conclusion, our results demonstrate that SCCS could restore colonic mucin O-glycosylation levels and intestinal homeostasis and contribute to enhancing intestinal barrier function.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease, characterized by focal iron overload. Herein, we reported that γ-glutamylcysteine (γGC) deletion in UC lesions intensified the disease by depleting intracellular GSH to induce macrophage ferroptosis, leading to macrophage M1 reprogramming and eventually exacerbating inflammation. To counteract this, the advanced microparticles (MPs)-based delivery system is selected to encapsulate γGC. The resulting γGC-MPs displayed the same porous and spiky morphology as their substrate's natural pollens, resulting in improved intestinal adhesion and enhanced lesion contact of γGC-MPs. Our results demonstrated that exogenous γGC supplementation could inhibit macrophage M1 polarization by restraining ferroptosis, as well as suppressing the PI3K/AKT pathway and TNF signaling pathway. Compared with free γGC, γGC-MPs significantly alleviated typical UC symptoms in dextran sulfate sodium (DSS)-induced colitis, evidenced by reduced intestinal inflammation, restored intestinal barrier function, and improved microbiota composition. Consequently, this study addressed critical gaps in understanding the causes of ferroptosis and its impact on macrophage reprogramming in UC, offering a novel synergistic therapeutic strategy for UC.

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is characterized by chronic intestinal inflammation and epithelial barrier disruption. Emerging evidence highlights mitochondrial dysfunction as a pivotal contributor to IBD pathogenesis, where impaired mitochondrial homeostasis in intestinal epithelial cells (IECs) disrupts redox balance, exacerbates oxidative stress, and triggers apoptosis, further compromising barrier integrity. This study investigated the therapeutic effects of Engeletin (Eng), a dihydroflavonoid from Smilax glabra Roxb., in dextran sulfate sodium (DSS)-induced colitis mice and colonic organoid models. Eng administration (10, 20, 40 mg/kg) significantly alleviated colitis symptoms, including weight loss, disease activity index (DAI) scores, and colon shortening, while restoring intestinal barrier integrity through the upregulation of tight junction proteins (ZO-1, claudin-1) and goblet cell preservation. Eng suppressed NF-κB-mediated inflammation and activated the Nrf2 antioxidant pathway, as well as reduced oxidative stress markers (MDA, CAT, GSH, and SOD). It attenuated epithelial apoptosis by balancing pro- and anti-apoptotic proteins (Bax/Bcl2, c-caspase3) and ameliorated mitochondrial dysfunction via enhanced ATP production, mtDNA levels, and complex I/IV activity. Mechanistically, Eng activated the AMPK/SIRT1/PGC-1α axis, and pharmacological inhibition of PGC-1α abolished its mitochondrial protective and anti-apoptotic effects. These findings demonstrate that Eng alleviates colitis by targeting mitochondrial homeostasis and oxidative stress through AMPK/SIRT1/PGC-1α signaling, offering a multitargeted strategy for IBD therapy.

Cellular senescence in the intestine can induce cell death, which extends beyond the mere clearance of senescent cells. This phenomenon is prevalent in inflammatory and immune-related diseases, particularly in inflammatory bowel disease (IBD). IBD is characterized by recurrent and chronic intestinal inflammation, with the occurrence and development of the disease being influenced by multiple factors, including genetics, environment, lifestyle, intestinal immunity, and gut microbiota. Chronic intestinal inflammation drives aging of the IBD immune system, reducing its efficiency and impairing the clearance of senescent cells. The disruption of cell death regulation and the interplay between cell death and cellular senescence contribute to disease progression in IBD, with inflammaging and immunosenescence playing the key role in this process. However, the mechanisms underlying the interplay between cell death and cellular senescence in the context of IBD remain unclear. Therefore, this paper comprehensively reviews the impact of cellular death and cellular senescence on intestinal aging in IBD, emphasizing the exploration of their potential interrelationships.

Inorganic dietary nanoparticles (IDNPs) are frequently utilized as food additives and in packaging, resulting in their exposure becoming a substantial yet often overlooked concern for patients with inflammatory bowel disease (IBD). Considering that impaired intestinal barrier function plays a central role in the pathogenesis of IBD, this review concentrates on the roles and mechanisms of IDNPs in the intestinal barrier (physical, chemical, biological, and immune barriers) of IBD patients. Previous studies have shown that different types of nanoparticles have varying effects on animals in diverse states. In this context, factors such as the source, size, shape, dosage, and duration of action of the nanoparticles, as well as the species, gender, dietary habits, and age of the animals, significantly influence research outcomes. Future studies should undertake more comprehensive explorations into the effects and mechanisms of IDNPs with diverse sources and properties in IBD patients.

Microcystin-LR (MC-LR), a class of cyclic heptapeptide compounds synthesized by cyanobacterial species, presents a significant risk to ecological systems and public health. Exposure to MC-LR was found to induce damage to various organs. One of the target organ systems affected by MC-LR is the gastrointestinal tract (GIT). However, the majority of studies regarding GIT focused on colorectal toxicity, with little attention paid to small intestinal toxic injuries, in particular jejunum. Thus, the aim of this study was to investigate the effects attributed to MC-LR exposure on apoptosis and underlying mechanisms utilizing a mouse jejunum injury model following chronic low-dose MC-LR treatment. A total of 40 C57BL/6 male mice were randomly divided into 4 groups with each group receiving drinking water containing 0, 1, 60, or 120 µg/L MC-LR for a duration of 12 months. Results indicated that exposure to MC-LR induced pathological alterations in jejunal tissue as evidenced by abnormal villous serration, crypt disorganization, and lymphocyte infiltration. TUNEL assays demonstrated a significant increase in apoptotic cell count in the 60 and 120 µg/L groups. The 60 and 120 µg/L MC-LR treatment groups exhibited elevated mRNA expression of Bax accompanied by significant reduction in mRNA expression of Bcl-2. The protein levels of cleaved caspase-3 were markedly elevated in the 60 and 120 µg/L MC-LR groups. The protein expression levels of p-RAF and p-ERK were significantly increased in the 60 and 120 µg/L MC-LR treatment groups. Data demonstrated suggest that the RAF/ERK signaling pathway may be involved in MC-LR- induced jejunal apoptosis.

In the early stages of development, piglets exhibit immature intestinal morphology and function, rendering them susceptible to a range of internal and external stressors, such as viral and bacterial infection, and mycotoxin exposure, which causes intestinal damage. The intestinal damage is characterized by various types of cell death within intestinal epithelium. The traditional cell death types have been categorized as necrosis, apoptosis, and autophagy. However, recent research has identified several forms of novel regulated cell death (RCD) such as necroptosis, pyroptosis, and ferroptosis. A growing body of evidence has underscored the pivotal role of necroptosis, pyroptosis, and ferroptosis in intestinal damage in pigs. Moreover, intervention strategies have been shown to mitigate these 3 RCDs when pigs are exposed to excessive adverse factors. This review aims to elucidate the role of these emerging RCDs in intestinal damage and summarize current understanding of their regulation by nutrients and bioactive substances in pigs. Our goal was to provide future intervention strategies designed to alleviate intestinal damage in pigs.

Ulcerative colitis (UC) is a lifelong chronic inflammatory disease that is characterized by the absence of specific markers for diagnosis and prognosis. TPM3 is an integral component of the thin filament, responsible for the structural stability of actin filaments and modulation of cytoskeletal function. This study investigated the regulatory role of TPM3 in UC and its potential mechanisms.

At the clinical level, TPM3 levels were assessed in serum and mucosal tissues of UC and other enteric disease. At the cellular level, the effects of TMP3 overexpressing lentivirus on Caco-2 cell phenotype and the barrier of IL-1β-induced UC model were explored. At the animal level, the effects of TMP3 overexpressing lentivirus on symptoms and colonic damage in a DSS-induced UC model were explored.

TPM3 expression in serum of UC patients was significantly lower than that of other enteric disease, and TPM3 levels in the intestinal mucosa showed a negative correlation with the Mayo score of UC patients. TPM3 overexpression alleviates IL-1β-induced apoptosis and inhibition of invasion and migration in UC model in vitro. In monolayer Caco-2 cells, TPM3 overexpression rescued the IL-1β-induced decrease in transepithelial electrical resistance and tight junction markers (ZO-1 and Occludin) and increase in permeability. In animal experiments, TPM3 overexpression increased body weight and colon length and decreased disease activity index in a DSS-induced UC model. In tissue staining, it alleviated pathological damage and upregulated Occuludin and TPM3 levels in the colon.

TPM3 levels correlated with UC disease course and TPM3 overexpression alleviated symptoms/phenotypes and barrier damage in UC models in vivo and in vitro. TPM3 may serve as a potential novel biomarker for UC diagnosis and prognosis.

Inflammatory bowel disease (IBD) is an idiopathic gastrointestinal disease with drastically increasing incidence rates. Due to its multifactorial etiology, a precise investigation of the pathogenesis is extremely difficult. Although reductionist cell culture models and more complex disease models in animals have clarified the understanding of individual disease mechanisms and contributing factors of IBD in the past, it remains challenging to bridge research and clinical practice. Conventional 2D cell culture models cannot replicate complex host-microbiota interactions and stable long-term microbial culture. Further, extrapolating data from animal models to patients remains challenging due to genetic and environmental diversity leading to differences in immune responses. Human intestine organ-on-chip (OoC) models have emerged as an alternative in vitro model approach to investigate IBD. OoC models not only recapitulate the human intestinal microenvironment more accurately than 2D cultures yet may also be advantageous for the identification of important disease-driving factors and pharmacological interventions targets due to the possibility of emulating different complexities. The predispositions and biological hallmarks of IBD focusing on host-microbiota interactions at the intestinal mucosal barrier are elucidated here. Additionally, the potential of OoCs to explore microbiota-related therapies and personalized medicine for IBD treatment is discussed.

Inflammatory bowel disease (IBD) is an autoimmune disorder primarily characterized by intestinal inflammation and recurrent ulceration, leading to a compromised intestinal barrier and inflammatory infiltration. This disorder's pathogenesis is mainly attributed to extensive damage or death of intestinal epithelial cells, along with abnormal activation or impaired death regulation of immune cells and the release of various inflammatory factors, which contribute to the inflammatory environment in the intestines. Thus, maintaining intestinal homeostasis hinges on balancing the survival and functionality of various cell types. Programmed cell death (PCD) pathways, including apoptosis, pyroptosis, autophagy, ferroptosis, necroptosis, and neutrophil extracellular traps, are integral in the pathogenesis of IBD by mediating the death of intestinal epithelial and immune cells. Natural products derived from plants, fruits, and vegetables have shown potential in regulating PCD, offering preventive and therapeutic avenues for IBD. This article reviews the role of natural products in IBD treatment by focusing on targeting PCD pathways, opening new avenues for clinical IBD management.

Intestinal barrier dysfunction is a prevalent and varied manifestation of acute pancreatitis (AP). Molecular mechanisms underlying the early intestinal barrier in AP remain poorly understood.

To explore the biological processes and mechanisms of intestinal injury associated with AP, and to find potential targets for early prevention or treatment of intestinal barrier injury.

This study utilized single-cell RNA sequencing of the small intestine, alongside in vitro and in vivo experiments, to examine intestinal barrier function homeostasis during the early stages of AP and explore involved biological processes and potential mechanisms.

Seventeen major cell types and 33232 cells were identified across all samples, including normal, AP1 (4x caerulein injections, animals sacrificed 2 h after the last injection), and AP2 (8x caerulein injections, animals sacrificed 4 h after the last injection). An average of 980 genes per cell was found in the normal intestine, compared to 927 in the AP1 intestine and 1382 in the AP2 intestine. B cells, dendritic cells, mast cells (MCs), and monocytes in AP1 and AP2 showed reduced numbers compared to the normal intestine. Enterocytes, brush cells, enteroendocrine cells, and goblet cells maintained numbers similar to the normal intestine, while cytotoxic T cells and natural killer (NK) cells increased. Enterocytes in early AP exhibited elevated programmed cell death and intestinal barrier dysfunction but retained absorption capabilities. Cytotoxic T cells and NK cells showed enhanced pathogen-fighting abilities. Activated MCs, secreted chemokine (C-C motif) ligand 5 (CCL5), promoted neutrophil and macrophage infiltration and contributed to barrier dysfunction.

These findings enrich our understanding of biological processes and mechanisms in AP-associated intestinal injury, suggesting that CCL5 from MCs is a potential target for addressing dysfunction.

Mitochondrial dysfunction contributes to the pathogenesis of ulcerative colitis (UC). As a mitochondrial isozyme of creatine kinases, which control energy metabolism, CKMT1 is thought to be a critical molecule in biological processes. However, the specific role of CKMT1 in intestinal inflammation remains largely unknown. Here, we observed markedly decreased CKMT1 expression in the colon tissues of UC patients and dextran sodium sulfate (DSS)-induced colitis mice. We generated intestinal epithelial-specific CKMT1 knockout mice and demonstrated the key role of CKMT1 in mitochondrial homeostasis, intestinal epithelial barrier function, oxidative stress, and apoptosis. In the in vitro experiments, CKMT1 expression limited the activation of the intrinsic and extrinsic apoptotic pathways in IECs. Mechanistically, the loss of CKMT1 expression in IECs increased TNF-α-induced mitochondrial reactive oxygen species (ROS) generation via reverse electron transfer (RET). RET-ROS promoted mitochondrial permeability transition pore (mPTP) opening, ultimately resulting in cell apoptosis during intestinal inflammation. In conclusion, our data demonstrated that CKMT1 is important in maintaining intestinal homeostasis and mitochondrial function. This study provides a promising basis for future research and a potential therapeutic target for inflammatory bowel disease (IBD).

Citrinin (CTN) is commonly found in animal feed and stored grains and poses a serious threat to human and animal health. Formation of the IP3R1-GRP75-VDAC1 complex has been shown to play a key role in intestinal defense against harmful stimuli, but the mechanism of its action in CTN-exposure-induced enterotoxicity is not clear. Therefore, the aim of this study was to investigate the role of the IP3R1-GRP75-VDAC1 complex in CTN-exposure-induced intestinal and IPEC-J2 monolayer cell damage in mice. It was shown that CTN exposure triggered intestinal cell pyroptosis and increased IP3R1-GRP75-VDAC1 complex formation as well as mitochondrial levels of calcium ions and mitochondrial reactive oxygen species (mtROS). And mtROS is considered to be a key factor in cellular pyroptosis. Therefore, the removal of mtROS by using Mito-Tempo was found to attenuate CTN-exposure-induced cellular pyroptosis but failed to attenuate mitochondrial calcium ion overload. However, silencing of GRP75 alleviated CTN-exposure-induced increases in the level of mtROS, mitochondrial calcium ions, and subsequent cellular pyroptosis. Therefore, this study confirms that CTN exposure induces cellular juxtaposition in intestinal tissues and points out that mitochondrial oxidative stress mediated by the IP3R1-GRP75-VDAC1 complex is a key mechanism by which CTN exposure triggers intestinal cellular pyroptosis.

Excessive endoplasmic reticulum (ER) stress in intestinal epithelial cells can lead to damage to the intestinal mucosal barrier, activate the signal transducer and activator of transcription 3 (STAT3)/nuclear factor kappa B (NF-κB) signaling pathway, and exacerbate the inflammatory response, thus participating in the pathogenesis of ulcerative colitis (UC). Mesalazine is a commonly used drug in the clinical treatment of UC. However, further studies are needed to determine whether mesalazine regulates the ER stress of intestinal epithelial cells, down-regulates the STAT3/NF-κB pathway to play a role in the treatment of UC.

To study the therapeutic effects of mesalazine on spontaneous colitis in interleukin-10 (IL-10)-/- mice.

The 24-week-old IL-10-/- mice with spontaneous colitis were divided into the model group and the 5-amino salicylic acid group. Littermates of wild-type mice of the same age group served as the control. There were eight mice in each group, four males and four females. The severity of symptoms of spontaneous colitis in IL-10-/- mice was assessed using disease activity index scores. On day 15, the mice were sacrificed. The colon length was measured, and the histopathological changes and ultrastructure of colonic epithelial cells were detected. The protein expressions of STAT3, p-STAT3, NF-κB, IκB, p-IκB, and glucose-regulated protein 78 were identified using Western blotting. The STAT3 and NF-κB mRNA expressions were identified using real-time polymerase chain reaction. The glucose-regulated protein 78 and C/EBP homologous protein expressions in colon sections were detected using immunofluorescence.

Mesalazine reduced the symptoms of spontaneous colitis in IL-10 knockout mice and the histopathological damage of colonic tissues, and alleviated the ER stress in epithelial cells of colitis mice. Western blotting and quantitative real-time polymerase chain reaction results showed that the STAT3/NF-κB pathway in the colon tissue of model mice was activated, suggesting that this pathway was involved in the pathogenesis of UC and might become a potential therapeutic target. Mesalazine could down-regulate the protein expressions of p-STAT3, NF-κB and p-IκB, and down-regulate the mRNA expression of STAT3 and NF-κB.

Mesalazine may play a protective role in UC by reducing ER stress by regulating the STAT3/NF-κB signaling pathway.

Fibrosis is a common complication in Crohn's disease (CD), often leading to intestinal strictures. This study aims to explore the transcriptomic signature of fibrostenotic ileal CD for a comprehensive characterization of biological and cellular mechanisms underlying intestinal fibrosis.

Nine CD patients undergoing surgery for fibrotic ileal strictures were prospectively recruited. RNA was extracted from fresh resected samples for bulk transcriptomics. Differentially expressed genes (DEGs) were identified (adj. P value < .05), and machine learning analyses were employed to compare gene expression patterns between strictures and non-strictured margins. Pathway enrichment analysis pinpointed relevant pathways. Furthermore, a random forest model was constructed to evaluate the significance of targeted genes. Relevant genes were subsequently validated through qPCR and further analyzed using a publicly available bulk RNA-seq dataset (GSE192786). Single-cell RNA sequencing (scRNA-seq) analysis was performed using the 10× Chromium Controller platform.

Bulk transcriptomics revealed unique transcriptomes with 81 DEGs, 64 significantly up-regulated, and 17 down-regulated in strictures compared to non-strictured margins. Up-regulated genes were mainly associated with inflammation, matrix and tissue remodeling, adipogenesis and cellular stress, while down-regulated genes were linked to epithelial barrier integrity. LY96, AKAP11, SRM, GREM1, EHD2, SERPINE1, HDAC1, and FGF2 showed high specificity for strictures. scRNA-seq linked up-regulated GREM1 exclusively to fibroblasts, while EHD2 and FGF2 showed upregulation in both fibroblasts and endothelial cells. LY96 and SRM were expressed by immune cells, whereas HDAC1, AKAP11, and SERPINE1 showed low expression across all cellular subsets.

This study comprehensively characterizes resected CD ileal strictures, elucidating main dysregulated pathways and identifying promising biomarkers and putative therapeutic targets.

Crohn's disease (CD) is a complex inflammatory condition with the potential for severe complications. Pyroptosis is an inflammatory form of programmed cell death, and the role of pyroptosis in intestinal epithelial cells of CD remains unclear.

In this study, pyroptosis-related hub genes were identified using datasets from the Gene Expression Omnibus database through differential expression analysis, machine learning algorithms, and single-cell sequencing analysis. Hub gene expression was validated using clinical samples and a trinitrobenzene sulfonic acid (TNBS)-induced colitis rat model.

Six pyroptosis-related hub genes (CASP1, IRF1, ZBP1, MLKL, MMP1, HTRA1) were identified. IRF1 and CASP1 exhibited significant upregulation in CD, including both colonic and ileal subtypes, with good diagnostic value across different CD subtypes. Additionally, these two genes were not elevated in any other intestinal disorders, except for ulcerative colitis. Single-cell sequencing analysis revealed a significant interaction between intestinal epithelial cells (IECs) and monocytes. The clinical samples further confirmed that the mRNA levels of IRF1 and CASP1 were significantly higher in CD patients compared to healthy controls. Additionally, the colitis rat model validated the upregulation of Irf1 and Casp1 at both mRNA and protein levels.

Our findings identified IRF1 and CASP1 as critical pyroptosis-related biomarkers for IECs in CD, contributing to the understanding of pyroptosis in CD pathogenesis.

Ulcerative colitis (UC) is a recurrent inflammation of the gastrointestinal tract, for which available treatment drugs are severely limited. Natural polysaccharides show potential for UC prevention. Herein, we extracted TCP80-1, a polysaccharide with significant anti-ulcerative colitis (UC) activity, from Tupistra chinensis Baker for the first time. Structure analysis revealed that TCP80-1 (3190 Da) was a levan-neoseries fructan containing → 6)-α-D-Glcp-(1→, →1)-β-D-Fruf-(2→, →1,6)-β-D-Fruf-(2→, →6)-β-D-Fruf-(2→ and β-D-Fruf-(2→ residues as backbone, with →6)-β-D-Fruf-(2→, and β-D-Fruf-(2→ as side chains substituted at C-6. The protective effect of TCP80-1 on UC was further evaluated using a UC Drosophila melanogaster model. The results demonstrated that TCP80-1 could alleviate the UC symptoms by reducing colonic atrophy, enhancing intestinal barrier, and promoting the proliferation and differentiation of intestinal stem cells (ISCs) into intestinal epithelial cells (IECs). Our findings provide important structural information about TCP80-1 and establish the foundation for the future progression and utilization of T. chinensis polysaccharide within the realm of UC therapy.

Inflammatory bowel diseases (IBD) are chronic, incurable pathologies with unknown causes, affecting millions of people. Pediatric-onset IBD, starting before the age of 18 years, are increasing, with more aggressive and extensive features than adult-onset IBD. These differences remain largely unexplained. Intestinal mucosal damage, cell death, DNA release from nuclear, mitochondrial, or microbiota sources, and DNA-sensing activating the cGAS-STING pathway may contribute to disease evolution. Increased colonic cGAS and STING are increasingly reported in experimental and human IBD. However, limited knowledge of the mechanisms involved hinders the development of new therapeutic options. Here, we discuss recent advances and unresolved questions regarding DNA release, DNA sensor activation, and the role and therapeutic potential of the cGAS-STING pathway in inflammatory colitis.

Dysregulation at the intestinal epithelial barrier is a driver of inflammatory bowel disease (IBD). However, the molecular mechanisms of barrier failure are not well understood. Here, we demonstrate dysregulated mitochondrial fusion in intestinal epithelial cells (IECs) of patients with IBD and show that impaired fusion is sufficient to drive chronic intestinal inflammation. We found reduced expression of mitochondrial fusion-related genes, such as the dynamin-related guanosine triphosphatase (GTPase) optic atrophy 1 (OPA1), and fragmented mitochondrial networks in crypt IECs of patients with IBD. Mice with Opa1 deficiency in the gut epithelium (Opa1i∆IEC) spontaneously developed chronic intestinal inflammation with mucosal ulcerations and immune cell infiltration. Intestinal inflammation in Opa1i∆IEC mice was driven by microbial translocation and associated with epithelial progenitor cell death and gut barrier dysfunction. Opa1-deficient epithelial cells and human organoids exposed to a pharmacological OPA1 inhibitor showed disruption of the mitochondrial network with mitochondrial fragmentation and changes in mitochondrial size, ultrastructure, and function, resembling changes observed in patient samples. Pharmacological inhibition of the GTPase dynamin-1-like protein in organoids derived from Opa1i∆IEC mice partially reverted this phenotype. Together, our data demonstrate a role for epithelial OPA1 in regulating intestinal immune homeostasis and epithelial barrier function. Our data provide a mechanistic explanation for the observed mitochondrial dysfunction in IBD and identify mitochondrial fusion as a potential therapeutic target in this disease.

Deoxynivalenol (DON) is a type of mycotoxin commonly found in food and animal feed. When consumed, it can have harmful effects on the intestine. The porcine digestive system is physiologically similar to that of humans, making pigs a suitable model for studying DON-induced enterotoxicity. However, the exact ways DON causes intestinal damage in pigs still need to be fully understood. To address this knowledge gap, this study aimed to identify hub genes associated with enterotoxicity caused by DON exposure. Transcriptomic datasets from porcine jejunal explants exposed to DON were extensively analyzed using bioinformatic techniques in this study. A total of 265 differentially expressed genes (DEGs) were identified, with 238 being up-regulated and 27 being down-regulated, indicating that exposure to DON tends to increase gene expression. Further analysis revealed that the up-regulated DEGs were enriched in tumor necrosis factor, nuclear factor kappa-B, mitogen-activated protein kinases, and Janus kinase/signal transducer and activator of transcription-related signaling pathways. In addition, Weighted gene co-expression network analysis was performed to identify highly co-expressed modules. Then, genes in the highest co-expressed module were intersected with the up-regulated DEGs to construct a Protein-Protein Interaction network, resulting in 237 overlapping genes. Subsequently, 6 hub genes (CXCR4, PTGS2, ICAM1, IL-1A, IL-1B, and IL-10) that played a central role in the response to DON were identified using cytohubba in conjunction with the Molecular Complex Detection. In summary, exposure to DON is more likely to result in increased rather than decreased gene expression. Six of the upregulated genes, which are involved in immunoregulation and inflammation, were identified as hub genes related to DON-induced enterotoxicity in pigs. This study provides new insights into the mechanisms underlying DON-induced enterotoxicity and could guide interventions for this condition.

Desmosomes are adhesive cell contacts abundant in tissues exposed to mechanical strain, such as the stratified and simple epithelia of the epidermis and mucous membranes, as well as the myocardium. Besides their role in mechanical cell cohesion, desmosomes also modulate pathways important for tissue differentiation, wound healing and immune responses. Dysfunctional desmosomes, resulting from pathogenic variants in genes encoding desmosomal components, autoantibodies targeting desmosomal adhesion molecules or inflammation, cause the life-threatening diseases arrhythmogenic cardiomyopathy and pemphigus and contribute to the pathogenesis of inflammatory bowel diseases. The Alpine Desmosome Disease Meeting 2024 (ADDM 2024), held in Grainau, Germany in October 2024, connected international researchers from basic sciences with clinical experts from dermatology, cardiology, gastroenterology and surgery. The participants discussed recent advances, identified hot topics in desmosome biology and disease and provided new concepts for pathogenesis and treatment approaches.

The risk of developing colorectal cancer (CRC) is increased in ulcerative colitis patients compared to the general population. This increased risk results from the state of chronic inflammation, a well-known tumour-promoting condition. This review explores the pathologic and molecular characteristics of colitis-associated colon cancer (CAC), emphasizing the distinct features from sporadic CRC. We focus on the key signalling pathways involved in the transition to CAC, highlighting the emerging role of alternative splicing in these processes, namely on how inflammation-induced alternative splicing can significantly contribute to the increased CRC risk observed among UC patients. This review calls for more transcriptomic studies to elucidate the molecular mechanisms through which inflammation-induced alternative splicing drives CAC pathogenesis. A better understanding of these splicing events is crucial as they may reveal novel biomarkers for disease progression and have the potential to target changes in alternative splicing as a therapeutic strategy.

Smilax glabra rhizome has a long history been used for clinical purposes in traditional Chinese medicinal for treating various inflammatory conditions. Engeletin1 (ENG) is one of the most abundant bioactive compounds found in Smilax glabra rhizome, with anti-inflammatory, antioxidant, and ulcer-preventing activities.

The purpose of this study was to investigate the ability of ENG to alleviate inflammatory symptoms and improve epithelial barrier integrity utilize a 2,4,6-trinitrobenzene sulfonic acid2 (TNBS)-induced murine model in Crohn's disease3 (CD)-like colitis, and to characterize the underlying anti-inflammatory mechanisms of action.

A colitis model was established in BALB/c mice and treated with ENG for 7 days. RAW264.7 macrophages were pre-treated with ENG and lipopolysaccharide4 (LPS) stimulation. The mice's weight and colon length were assessed. qPCR and Western blotting were used to analyze gene expression and TLR4-NFκB pathway. Flow cytometry was used to analyze the polarization states of the macrophages.

Treatment with ENG was sufficient to significantly alleviate symptoms of inflammation and colonic epithelial barrier integrity in treated mice. Significant inhibition of TNF-α, IL-1β, and IL-6 expression was observed following ENG treatment in vivo and in vitro. ENG was also determined to be capable of inhibiting the expression of iNOS and CD86, inhibited M1 macrophage polarization in vitro, as well as the TLR4-NFκB signaling pathway. Molecular docking showed a highly stable binding between ENG and TLR4.

ENG has been proven to alleviate inflammation and ameliorate the damage of epithelial barrier in CD-like colitis. ENG also suppressed the M1 macrophages polarization and the inhibited inflammatory cytokines. TLR4-NFκB signaling pathway, especially TLR4, may be the target of ENG. These data offer a new insight into the therapeutic mechanisms of ENG.

The intestinal epithelium, beyond its role in absorption and digestion, serves as a critical protective mechanical barrier that delineates the luminal contents and the gut microbiota from the lamina propria within resident mucosal immune cells to maintain intestinal homeostasis. The barrier is manifested as a contiguous monolayer of specialized intestinal epithelial cells (IEC), interconnected through tight junctions (TJs). The integrity of this epithelial barrier is of paramount. Consequently, excessive IEC death advances intestinal permeability and as a consequence thereof the translocation of bacteria into the lamina propria, subsequently triggering an inflammatory response, which underpins the clinical disease trajectory of inflammatory bowel disease (IBD). A burgeoning body of evidence illustrates a landscape where IEC undergoes several the model of programmed cell death (PCD) in the pathophysiology and pathogenesis of IBD. Apoptosis, necroptosis, and pyroptosis represent the principal modalities of PCD with intricate specific pathways and molecules. Ample evidence has revealed substantial mechanistic convergence and intricate crosstalk among these three aforementioned forms of cell death, expanding the conceptualization of PANoptosis orchestrated by the PNAoptosome complex. This review provides a concise overview of the molecular mechanisms of apoptosis, necroptosis, and pyroptosis. Furthermore, based on the crosstalk between three cell deaths in IEC, this review details the current knowledge regarding PANoptosis in IEC and its regulation by natural products. Our objective is to broaden the comprehension of innovative molecular mechanisms underlying the pathogenesis of IBD and to furnish a foundation for developing more natural drugs in the treatment of IBD, benefiting both clinical practitioners and research workers.

Ulcerative colitis (UC) can cause severe oxidative stress in the colon, which can lead to tissue damage and an imbalance in the normal gut microbiota. Ellagic acid (EA) is one of the main types of plant polyphenols with improved pharmacological effects such as antioxidant, anti-inflammatory, and antibacterial properties. However, currently, the studies on the impact of EA on the gut microbiota and its potential to alleviate UC in mice through the ROS/NLRP3 pathway are limited. In this study, dextran sodium sulfate (DSS) was used to construct a UC mouse model, which was then treated with EA as an intervention for UC. The results revealed that EA alleviated the trend of liver, spleen, and weight changes in UC mice and improved colon oxidative stress, inflammation, and pathological damage. Mechanistically, DSS-induced UC indicated a significant increase in ROS/NLRP3 pathway-related factors, whereas EA intervention activated the Nrf2 pathway to reduce these factors. Furthermore, the DSS group had a reduced abundance of Firmicutes (59.02%) and an increased abundance of Bacteroides and Proteobacterium by 1.8 times and 10.16%; however, EA intervention reversed these changes, thus alleviating UC. The findings of this study revealed that EA could significantly enhance the composition of gut microbiota in UC and reduce the inflammatory response, colonic damage as well as oxidative stress caused by DSS by regulating the ROS/NLRP3 pathway. These results provide novel perspectives on the prevention and treatment strategies of UC and highlight the therapeutic benefits of EA in managing colitis.

A vicious cycle of dysregulated intestinal epithelial cell death, intestinal barrier defect, and subsequent inflammation response is core to chronic ulcerative colitis (UC). Modified Jiaoqi Powder (MJQP), a traditional Chinese medicine formula, has been clinically applied to treat chronic relapsing and chronic persistent types of UC. Nevertheless, the underlying mechanisms of MJQP in chronic UC remains unknown.

The present study aimed to demonstrate the favorable effects and potential molecular mechanisms of MJQP in chronic UC.

The chemical components of MJQP and MJQP drug serum were identified by LC-MS/MS. The curative effects of MJQP were evaluated in a well-established DSS-induced chronic UC mice model by measuring body weight, colon length, disease activity index (DAI) and histological scores. Serum cytokines, including interleukin (IL)-1β, IL-12, IL-13, IL-4, tumor necrosis factor-alpha (TNF-α), and IFN-γ were measured using enzyme-linked immunosorbent assay. Western blotting, immunofluorescence, and MTT assay were used to analyze the effects of MJQP on colonic barrier function in chronic UC mice and human epithelial cell lines. TUNEL assay, western blotting, and flow cytometry were used to examine the related apoptosis indicators. An electron microscope was used to observe autophagosomes and autolysosomes, while western blotting and immunofluorescence were used to detect autophagy-associated proteins. Network pharmacology was used to predict potential targets and pathways of MJQP in UC. Finally, the TNF pathway-related proteins were detected by immunohistochemistry and western blotting.

MJQP administration prevented the UC progression, as evidenced by faster weight gain, longer colon length, lower histological scores and DAI, and up-/down- regulation of inflammatory factors. The expression of tight junction proteins, ki67, and E-cadherin increased dose-dependently after MJQP intervention. Moreover, MJQP treatment promoted the viability of NCM460 and Caco2 cells in a concentration-dependent manner. MJQP dose-dependently decreased the proportion of TUNEL-positive cells and attenuated the pro-apoptotic proteins cleaved-caspase 8 and cleaved-caspase 3 in colonic tissues. Flow cytometry also showed that MJQP dose-dependently decreased the apoptotic cell population of LPS-induced NCM460 and Caco2 cells. Electron microscopy revealed that autophagosomes and autolysosomes were significantly improved in the MJQP-treated groups. Additionally, autophagy-related proteins were significantly expressed after MJQP treatment. Network pharmacological analysis predicted that MJQP may alleviate chronic UC by promoting intestinal epithelial cell proliferation and affecting TNF-related signaling pathways. As anticipated, the TNF pathway-associated proteins were attenuated dose-dependently in colonic tissues after MJQP treatment.

These results provide novel therapeutic strategies indicating that MJQP may be a promising candidate treatment for chronic UC by promoting epithelial barrier restitution by enhancing epithelial autophagy against TNF-mediated apoptosis.

Nutrient availability strongly affects intestinal homeostasis. Here, we report that low-protein (LP) diets decrease amino acids levels, impair the DNA damage response (DDR), cause DNA damage and exacerbate inflammation in intestinal tissues of male mice with inflammatory bowel disease (IBD). Intriguingly, loss of nuclear fragile X mental retardation-interacting protein 1 (NUFIP1) contributes to the amino acid deficiency-induced impairment of the DDR in vivo and in vitro and induces necroptosis-related spontaneous enteritis. Mechanistically, phosphorylated NUFIP1 binds to replication protein A2 (RPA32) to recruit the ataxia telangiectasia and Rad3-related (ATR)-ATR-interacting protein (ATRIP) complex, triggering the DDR. Consistently, both reintroducing NUFIP1 but not its non-phospho-mutant and inhibition of necroptosis prevent bowel inflammation in male Nufip1 conditional knockout mice. Intestinal inflammation and DNA damage in male mice with IBD can be mitigated by NUFIP1 overexpression. Moreover, NUFIP1 protein levels in the intestine of patients with IBD were found to be significantly decreased. Conclusively, our study uncovers that LP diets contribute to intestinal inflammation by hijacking NUFIP1-DDR signalling and thereby activating necroptosis.

Three-phase partitioning (TPP) is promising for isolating bioactive polysaccharides, but t-butanol's environmental impact limits its application. Deep eutectic solvents can serve as a green and recyclable alternative to t-butanol. This study introduces an ultrasonic-assisted DES three-phase partitioning (UA-TPP-DES) system to extract and purify American ginseng polysaccharides (AGPs). The optimized DES-4, composed of lauric acid and nonanoic acid (molar ratio = 1:1), achieved a 35.28 % extraction yield under specific conditions and can be recycled five times with minimal yield loss. AGP-DES-4 has a broad molecular weight distribution (2.48-174.64 kDa) and mainly consists of mannose, glucose, galactose, and arabinose. In vivo Drosophila models show that AGP-DES-4 improves UC fly survival and enhances intestinal barrier function by regulating the proliferation and differentiation of intestinal epithelial cells (IECs) and intestinal stem cells (ISCs). Our results highlight the effectiveness of the AGP-DES-4 extraction method and its potential therapeutic value for treating UC.

Ulcerative colitis (UC) is a chronic inflammatory disease driven by immune dysregulation. PANoptosis, a novel form of programmed cell death, has been implicated in inflammatory diseases, but its specific role in UC remains unclear. This study aimed to identify PANoptosis-related genes (PRGs) that may contribute to immune dysregulation in UC.

Using bioinformatics analysis of the GEO databases, we identified seven hub PRGs. Based on these genes, we developed a predictive model to differentiate UC patients from healthy controls, and evaluated its diagnostic performance using ROC curve analysis. We further conducted functional enrichment, GSVA, and immune infiltration analyses. Immunohistochemistry (IHC) was used to validate the expression of hub genes in UC patients.

The prediction model, based on the seven hub genes, exhibited diagnostic ability in discriminating UC patients from controls. Furthermore, these hub PRGs were found to be associated with immune cells, including dendritic cells, NK cells, macrophages, regulatory T cells (Tregs), and CD8+ T cells. They were also linked to key signaling pathways implicated in UC pathogenesis, such as IFNγ, TNFα, IL6-and JAK-STAT3, as well as hypoxia and apoptosis. Immunohistochemistry analysis validated the expression levels of hub PRGs in UC patients using paraffin sections of intestinal biopsy specimens.

This study identified PANoptosis-related genes with potential diagnostic value for UC and suggest that PANoptosis may contribute to the pathogenesis of UC by regulating specific immune cells and interacting with key signaling pathways. This highlights the potential importance of PANoptosis-related genes as therapeutic targets in UC management.