Intestinal Mucosal Barrier Research Articles

P1204 Oral Streptococcus mutans isolates aggravated colitis in mice

Abstract Background The incidence of inflammatory bowel disease (IBD) is increasing year by year and the mechanism is unclear. A great number of studies have shown that the gut microbiota composition of IBD patients has changed and the diversity of gut microbiota decreases. The abundance of firmicutes decreases, and the abundance of Proteobacteria increases, which eventually leads to the immune disorders and intestinal inflammation. The mouth is the "gateway" of the digestive tract, which has various microbiota. The entry of extraneous microbiota from the mouth into the intestines play an important role in influencing the composition of the gut microbiota. The continuous disorder of the oral microenvironment (such as periodontitis and dental caries) are also closely related to intestinal inflammation. Methods A series of in vivo and in vitro experiments were conducted to investigate the effect and mechanism of S. mutans on colitis mice. Results S.mutans strain UA159 which is closely related to dental caries significantly aggravated colitis in DSS induced mice, as shown by body weight loss, shorter colon length, and increased inflammatory histological scores (Fig1A). UA159 up-regulated intestinal pro-inflammatory cytokines and inhibited the expression of barrier molecules in DSS mice (Fig1B). The proportion of adaptive immune cells (Th1, Th17) was up-regulated in intestinal lamina propria of UA159-administered mice (Fig1C-D).The fecal microbiota composition of UA159 mice was different from control group. The pro-inflammatory effects of UA159 on DSS mice disappeared when antibiotics were used to eliminate the intestinal microbiota. It is suggested that S.mutans may play a proinflammatory role by influencing the intestinal microbiota of mice (Fig1E). We followed 55 IBD patients for more than 1 year and found that IBD patients with poor control had a higher proportion of S.mutans in saliva (Fig1F). S.mutans strains were isolated from IBD saliva samples and were found to cluster in different branches in the phylogenetic tree (Fig1G). S.mutans isolates have different pro-inflammatory effects on colitis mice and intestinal epithelial cells (Fig1H-I). Subsequent experiments are under way to further explore the mechanism leading to the differences of the pro-inflammatory effects. Conclusion Our study were the first to find that oral S.mutans has aggravated intestinal inflammation. S.mutans UA159 aggravated colitis in mice through damaging intestinal mucosal barrier function, enhancing immune response and disrupting intestinal microbiota (Fig1J). The difference in pro-inflammatory effect of S.mutans derived from different IBD patients saliva may be related to the individual clinical outcome.

Multi-targeting inulin-based nanoparticles with cannabidiol for effective prevention of ulcerative colitis

The pathogenesis of ulcerative colitis (UC) is closely related to severe inflammation, damaged colonic mucosal barrier, increased oxidative stress and intestinal ecological imbalance. However, due to the nonspecific distribution and poor bioavailability of drugs, UC treatment is still a serious challenge. Here, a mitochondria/colon dual targeted nanoparticles based on redox response was developed to effectively alleviate UC. Cannabidiol nanoparticles (CBD NPs) with a particle size of 143.2 ± 3.11 nm were prepared by self-assembly using polymers (TPP–IN–LA) obtained by modifying inulin with (5-carboxypentyl) triphenyl phosphonium bromide (TPP) and α-lipoic acid (α-LA). Excitingly, the constructed CBD NPs showed excellent mitochondrial targeting, with a Pearson correlation coefficient of 0.76 at 12 h. The results of animal imaging in vivo showed that CBD NPs could be effectively accumulated in colon tissue. Not only that, CBD showed significant glutathione stimulated release in the presence of 10 mM glutathione at pH 7.4. The results of in vivo animal experiments showed that CBD NPs significantly ameliorated DSS-induced colonic inflammation by modulating the TLR4-NF-κB signaling pathway. Moreover, CBD NPs significantly improved the histological damage of colon in UC mice, increased the expression level of tight junction protein ZO-1, and effectively restored the intestinal mucosal barrier function and intestinal mucosal permeability. More importantly, CBD NPs significantly improved the species composition, abundance and amount of short chain fatty acids of intestinal flora in UC mice, thus effectively maintaining the balance of intestinal flora. The dual-targeted and glutathione-responsive nanoparticles prepared in this study provide a promising idea for achieving targeted delivery of CBD for effective treatment of UC.

Celecoxib alleviates the DSS-induced ulcerative colitis in mice by enhancing intestinal barrier function, inhibiting ferroptosis and suppressing apoptosis

Introduction Ulcerative colitis (UC) is an inflammatory intestine disease characterized by dysfunction of the intestinal mucosal barrier, ferroptosis, and apoptosis. Previous researches suggest that celecoxib, a nonsteroidal anti-inflammatory drug, holds promise in alleviating inflammation in UC. Therefore, this study aims to investigate the effects and mechanisms of celecoxib in UC. Methods To identify ferroptosis-related drugs and genes associated with UC, we utilized the Gene Expression Omnibus (GEO), FerrDb databases, and DGIdb database. Subsequently, we established a 2.5% DSS (Dextran sulfate sodium)-induced colitis model in mice and treated them with 10 mg/kg of celecoxib to validate the bioinformatics results. We evaluated histological pathologies, inflammatory response, intestinal barrier function, ferroptosis markers, and apoptosis regulators. Results Celecoxib treatment significantly ameliorated DSS-induced UC in mice, as evidenced by the body weight change curve, colon length change curve, disease activity index (DAI) score, and histological index score. Celecoxib treatment reduced the level of pro-inflammatory factors and promoted the expressions of intestinal tight junction proteins such as Claudin-1 and Occludin, thereby restoring the integrity of the intestinal mucosal barrier. Furthermore, celecoxib treatment reversed the ferroptosis characteristics in DSS-induced mice by increasing glutathione (GSH), decreasing malondialdehyde (MDA), and increasing the expression of GPX-4 and xCT. Additionally, apoptosis was induced in mice with UC, as evidenced by increased Caspase3, BAD, P53, BAX, Caspase9 and Aifm1 production, and decreased expression of BCL-XL and BCL2. Celecoxib treatment significantly reversed the apoptotic changes in DSS-induced mice. Conclusion Our findings suggest that celecoxib effectively treats DSS-induced UC in mice by inhibiting ferroptosis and apoptosis.

The antimicrobial peptide Abaecin alleviates colitis in mice by regulating inflammatory signaling pathways and intestinal microbial composition

Abaecin is a natural antimicrobial peptide (AMP) rich in proline from bees. It is an important part of the innate humoral immunity of bees and has broad-spectrum antibacterial ability. This study aimed to determine the effect of Abaecin on dextran sulfate sodium (DSS) -induced ulcerative colitis (UC) in mice and to explore its related mechanisms. Twenty-four mice with similar body weight were randomly divided into 4 groups. 2.5% DSS was added to drinking water to induce colitis in mice. Abaecin and PBS were administered rectally on the third, fifth, and seventh days of the experimental period. The results showed that Abaecin significantly alleviated histological damage and intestinal mucosal barrier damage caused by colitis in mice, reduced the concentration of pro-inflammatory cytokines IL-1β, IL-6, TNF-α, IFN-γ, and the phosphorylation of NF-κB / MAPK inflammatory signaling pathway proteins, and improved the composition of intestinal microorganisms. These findings suggest that Abaecin may have potential prospects for the treatment of UC.

Effects of Antibiotic Residues on Fish Gut Microbiome Dysbiosis and Mucosal Barrier-Related Pathogen Susceptibility in Zebrafish Experimental Model.

The symbiotic community of microorganisms in the gut plays an important role in the health of the host. While many previous studies have been performed on the interactions between the gut microbiome and the host in mammals, studies in fish are still lacking. In this study, we investigated changes in the intestinal microbiome and pathogen susceptibility of zebrafish (Danio rerio) following chronic antibiotics exposure. The chronic antibiotics exposure assay was performed on zebrafish for 30 days using oxytetracycline (Otc), sulfamethoxazole/trimethoprim (Smx/Tmp), or erythromycin (Ery), which are antibiotics widely used in the aquaculture industry. The microbiome analysis indicated that Fusobacteria, Proteobacteria, Firmicutes, and Bacteroidetes were the dominant phyla in the gut microbiome of the zebrafish used in this study. However, in Smx/Tmp-treated zebrafish, the compositions of Fusobacteria and Proteobacteria were changed significantly, and in Ery-treated zebrafish, the compositions of Proteobacteria and Firmicutes were altered significantly. Although alpha diversity analysis showed that there was no significant difference in the richness, beta diversity analysis revealed a community imbalance in the gut microbiome of all chronically antibiotics-exposed zebrafish. Intriguingly, in zebrafish with dysbiosis in the gut microbiome, the pathogen susceptibility to Edwardsiella piscicida, a representative Gram-negative fish pathogen, was reduced. Gut microbiome imbalance resulted in a higher count of goblet cells in intestinal tissue and an upregulation of genes related to the intestinal mucosal barrier. In addition, as innate immunity was enhanced by the increased mucosal barrier, immune and stress-related gene expression in the intestinal tissue was downregulated. In this study, we provide new insight into the effect of gut microbiome dysbiosis on pathogen susceptibility.

Study on the Anti-Ulcerative Colitis Effect of Pseudo-Ginsenoside RT4 Based on Gut Microbiota, Pharmacokinetics, and Tissue Distribution.

The purpose of this study was to explore the therapeutic effect of the oral administration of pseudo-ginsenoside RT4 (RT4) on ulcerative colitis (UC), and to determine the rate of absorption and distribution of RT4 in mice with UC. Balb/c mice were induced using dextran sulfate sodium salts (DSS) to establish the UC model, and 10, 20, or 40 mg/kg of RT4 was subsequently administered via gavage. The clinical symptoms, inflammatory response, intestinal barrier, content of total short-chain fatty acids (SCFAs), and gut microbiota were investigated. Caco-2 cells were induced to establish the epithelial barrier damage model using LPS, and an intervention was performed using 4, 8, and 16 µg/mL of RT4. The inflammatory factors, transient electrical resistance (TEER), and tight-junction protein expression were determined. Finally, pharmacokinetic and tissue distribution studies following the intragastric administration of RT4 in UC mice were performed. According to the results in mice, RT4 decreased the disease activity index (DAI) score, restored the colon length, reduced the levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), and boosted the levels of immunosuppressive cytokine IL-10, increased the content of SCFAs, improved the colonic histopathology, maintained the ultrastructure of colonic mucosal epithelial cells, and corrected disturbances in the intestinal microbiota. Based on the results in caco-2 cells, RT4 reduced the levels of TNF-α, IL-6, and IL-1β; protected integrity of monolayers; and increased tight-junction protein expression. Additionally, the main pharmacokinetic parameters (Cmax, Tmax, t1/2, Vd, CL, AUC) were obtained, the absolute bioavailability was calculated as 18.90% ± 2.70%, and the main distribution tissues were the small intestine and colon. In conclusion, RT4, with the features of slow elimination and directional distribution, could alleviate UC by inhibiting inflammatory factors, repairing the intestinal mucosal barrier, boosting the dominant intestinal microflora, and modulating the expression of SCFAs.

TSP50 Attenuates DSS-Induced Colitis by Regulating TGF-β Signaling Mediated Maintenance of Intestinal Mucosal Barrier Integrity.

The integrity of the intestinal mucosal barrier is crucial for protecting the intestinal epithelium against invasion by commensal bacteria and pathogens, thereby combating colitis. The investigation revealed that the absence of TSP50 compromised the integrity of the intestinal mucosal barrier in murine subjects. This disruption facilitated direct contact between intestinal bacteria and the intestinal epithelium, thereby increasing susceptibility to colitis. Mechanistic analysis indicated that TSP50 deficiency in intestinal stem cells (ISCs) triggered aberrant activation of the TGF-β signaling pathway and impeded the differentiation of goblet cells in mice, leading to impairment of mucosal permeability. By inhibiting the TGF-β pathway, the functionality of the intestinal mucosal barrier is successfully restored and mitigated colitis in TSP50-deficient mice. In conclusion, TSP50 played a crucial role in maintaining the intestinal mucosal barrier function and exhibited the preventive effect against the development of colitis by regulating the TGF-β signaling pathway.

Hydroxychloroquine ameliorates immune functionality and intestinal flora disorders of IgA nephropathy by inhibition of C1GALT1/Cosmc pathway

Background Hydroxychloroquine (HCQ) has emerged as a potential and secure antiproteinuric agent in IgA nephropathy (IgAN). This study endeavored to explore the impact of HCQ on the immune functionality and intestinal flora disorders in IgAN rats, as well as to elucidate the underlying mechanisms through in vivo and in vitro experiments. Methods IgAN model was established in Sprague-Dawley rats through the administration of BSA, LPS, and CCl4, and the IgAN rats received a continuous 8-week treatment with HCQ. Moreover, the human glomerular mesangial cells (HMCs) were incubated with IgA1 to establish an in vitro cellular model of IgAN. At the end of experimental period, samples were collected for further analysis. Results HCQ ameliorated the elevated levels of 24hUTP, SCr, BUN, the number of urinary RBC, and the activation of inflammation-related proteins within the TLR4/NF-κB signaling pathway. In the IgAN rat group, there was a pronounced escalation in IgA deposition, mesangial matrix hyperplasia, and glomerular inflammatory cell infiltration, while the administration of HCQ effectively mitigated these pathological changes. In addition, the reduced production of CD4+CD25+Foxp3+ Treg in the IgAN group was effectively reversed by HCQ. Furthermore, HCQ has the capacity to restore the compromised state of the intestinal mucosal barrier induced by IgAN and mitigate the circumstances of intestinal permeability and disruption in the intestinal flora. Conclusion HCQ diminishes IgA aberrant glycosylation levels, ameliorates renal and intestinal histopathological damage, and attenuates intestinal flora disorders and immune dysfunction in IgAN rats by means of activating the C1GALT1/Cosmc pathway.

The role of the Notch signalling pathway in the pathogenesis of ulcerative colitis: from the perspective of intestinal mucosal barrier.

Ulcerative colitis is a common digestive disorder worldwide, with increasing incidence in recent years. It is an urgent problem to be solved, as it seriously affects and threatens the health and life of the global population. Studies have shown that dysfunction of the intestinal mucosal barrier is a critical pathogenic factor and molecular basis of ulcerative colitis, and some scholars have described it as a "barrier organ disease." While the Notch signalling pathway affects a series of cellular processes, including proliferation, differentiation, development, migration, and apoptosis. Therefore, it can regulate intestinal stem cells, CD4+ T cells, innate lymphoid cells, macrophages, and intestinal microbiota and intervene in the chemical, physical, immune, and biological mucosal barriers in cases of ulcerative colitis. The Notch signalling pathway associated with the pathogenesis of ulcerative colitis has distinct characteristics, with good regulatory effects on the mucosal barrier. However, research on ulcerative colitis has mainly focused on immune regulation, anti-inflammatory activity, and antioxidant stress; therefore, the study of the Notch signalling pathway suggests the possibility of understanding the pathogenesis of ulcerative colitis from another perspective. In this article we explore the role and mechanism of the Notch signalling pathway in the pathogenesis of ulcerative colitis from the perspective of the intestinal mucosal barrier to provide new targets and theoretical support for further research on the pathogenesis and clinical treatment of ulcerative colitis.

Entero-toxigenic Bacteroides fragilis contributes to intestinal barrier injury and colorectal cancer progression by mediating the BFT/STAT3/ZEB2 pathway

ABSTRACT Our previous findings confirmed the high enrichment of Bacteroides fragilis (BF) in fecal samples from patients with colorectal cancer (CRC). The intestinal mucosal barrier is the first defense of the organism against commensal flora and intestinal pathogens and is closely associated with the occurrence and development of CRC. Therefore, this study aimed to investigate the molecular mechanisms through which BF mediates intestinal barrier injury and CRC progression. SW480 cells and a Caco2 intestinal barrier model were treated with entero-toxigenic BF (ETBF), its enterotoxin (B. fragilis toxin, BFT), and non-toxigenic BF (NTBF). Cell counting kit-8, flow cytometry, wound healing and transwell assays were performed to analyze the proliferation, apoptosis, migration, and invasion of SW480 cells. Transmission electron microscopy, FITC-dextran, and transepithelial electrical resistance (TEER) were used to analyze damage in the Caco2 intestinal barrier model. The Azoxymethane/Dextran Sulfate Sodium (AOM/DSS) animal model was established to evaluate the effect of ETBF on intestinal barrier injury and CRC progression in vivo. ETBF and BFT enhanced the viability, wound healing ratio, invasion, and EMT of SW480 cells. In addition, ETBF and BFT disrupted the tight junctions and villus structure in the intestinal barrier model, resulting in increased permeability and reduced TEER. Similarly, the expression of intestinal barrier-related proteins (MUC2, Occludin and Zo-1) was restricted by ETBF and BFT. Interestingly, the STAT3/ZEB2 axis was activated by ETBF and BFT, and treatment with Brevilin A (a STAT3 inhibitor) or knockdown of ZEB2 limited the promotional effect of ETBF and BFT on the SW480 malignant phenotype. In vivo experiments also confirmed that ETBF colonization accelerated tumor load, carcinogenesis, and intestinal mucosal barrier damage in the colorectum of the AOM/DSS animal model, and that treatment with Brevilin A alleviated these processes. ETBF-secreted BFT accelerated intestinal barrier damage and CRC by activating the STAT3/ZEB2 axis. Our findings provide new insights and perspectives for the application of ETBF in CRC treatment.

Magnesium isoglycyrrhizinate attenuates nonalcoholic fatty liver disease by strengthening intestinal mucosal barrier

BackgroundNon-alcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) has recently risen to the top spot among chronic liver diseases in the world. However, there are no recognized treatments for it. Magnesium isoglycyrrhizate (MgIG) has potential as a NAFLD/NASH therapy. AimsTo investigate the efficacy of MgIG in improving NAFLD/NASH and the possible pathways and mechanisms. MethodsC57bl/6 mice were fed a high-fat diet (HFD) and 1 % dextran sulfate sodium (DSS) for 12 weeks to establish the NAFLD/NASH model. MgIG was administered by gavage during the last 7 weeks. First, the therapeutic effects of MgIG on hepatic steatosis and fibrosis, liver injury, and inflammation in the NAFLD/NASH mice were evaluated. Second, liver oxidative stress and hepatocyte apoptosis were detected. Finally, the effect of MgIG on intestinal permeability and short-chain fatty acid (SCFA) levels in mice’s intestinal contents were examined. ResultsMgIG administration attenuated HFD-induced hepatic steatosis and fibrosis, improved serum biochemical and NAFLD/NASH mice, reduced liver oxidative stress and hepatocyte apoptosis, improved intestinal permeability, and increased fecal SCFA levels in NAFLD/NASH mice. ConclusionMgIG protects against HFD-induced NAFLD/NASH through multiple pathways as well as mechanisms and holds promise as a potentially effective treatment for NAFLD/NASH.

Dietary Supplementation with Omega‐3 PUFAs Modulates Gut Microbiota and Protects the Intestinal Barrier in Senescence‐Accelerated Mice

Intestinal mucosal barrier aging is a major cause of the occurrence and development of many chronic diseases in older adults and is closely associated with gut microbiota. However, it remains unclear whether exogenous supplementation with omega‐3 polyunsaturated fatty acids (ω‐3 PUFAs) can ameliorate aging‐induced intestinal mucosal barrier damage by regulating the gut microbiota. This study was conducted to explore the roles of ω‐3 PUFAs and gut microbiota in the process of maintaining the intestinal mucosal barrier. Senescence‐accelerated mouse prone 8 (SAMP8) mice were used to establish a geriatric animal model and given reasonable doses of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplemented diets for six months to validate the effect of ω‐3 PUFAs. Differences in the composition and function of gut microbiota were analyzed using 16S rRNA gene sequencing. This study revealed that aging SAMP8 mice showed increased intestinal permeability and gut microbiota disorder. Long‐term supplementation with ω‐3 PUFAs reduced intestinal mucosal permeability (P < 0.05), regulated gut microbiota, strengthened the microecological interactions, and enhanced enrichment of metabolic pathways producing short‐chain fatty acids (P < 0.05), ultimately ameliorating intestinal mucosal barrier dysfunction. Furthermore, we demonstrated that ω‐3 PUFAs could maintain the aging intestinal mucosal barrier by regulating the relative abundance of eight key characteristic microbial strains to increase the concentration of DHA and EPA in the plasma and colon tissue and reduced intestinal permeability of SAMP8 mice. ω‐3 PUFAs can significantly ameliorate intestinal mucosal barrier function in senescence‐accelerated mice, and this effect is mediated by the gut microbiota. The findings of our study provide a scientific basis for the rational intake of ω‐3 PUFAs in older adults to maintain intestinal mucosal barrier function.

Thonningianin A ameliorated renal interstitial fibrosis in diabetic nephropathy mice by modulating gut microbiota dysbiosis and repressing inflammation.

This study was conducted to examine the potential health benefits of thonningianin A (TA) on renal injury and interstitial fibrosis in diabetic nephropathy (DN) mice. In this study, a DN mice model was established using male C57BL/6 mice injected with streptozotocin (STZ, 50mg/kg) intraperitoneally and treated with TA for 12weeks. Firstly, the therapeutic and anti-fibrotic effects of TA on DN were evaluated. Secondly, the effect of TA on renal inflammation was evaluated and Western blot was used to detect the changes of NLRP3/ASC/Caspase-1 pathway-related protein expressions in kidney. Furthermore, the effect of TA on impairments in the intestinal mucosa barrier was evaluated and the changes of lipopolysaccharide (LPS) levels in feces and serum were detected by ELISA. Finally, 16S rRNA sequencing was used to detect alteration of gut microbiota diversity and abundance in mice after TA treatment. The results showed that TA markedly mitigated blood glucose (Glu), decreased 24-h urinary total protein (24hUTP), improved renal dysfunction and kidney index (KI) in DN mice. Furthermore, TA significantly alleviated renal injury and interstitial fibrosis, repressing renal inflammation. Western blot results showed that the NLRP3/ASC/Caspase-1 signaling pathway-related proteins decreased after TA treatment. In addition, TA also ameliorated impairments in the intestinal mucosa barrier and restored the expressions of intestinal tight junction proteins (Claudin-1, Occludin and ZO-1). Subsequently, it reduced LPS levels of DN mice in fecal and serum. Furthermore, 16S rRNA high-throughput sequencing showed that TA modulated gut microbiota dysbiosis and decreased the abundance of Gram-negative bacteria (Proteobacteria and Escherichia-Shigella). This study suggested that TA might exert a beneficial effect on renal interstitial fibrosis in DN mice by modulating gut microbiota dysbiosis, ameliorating impairments in the intestinal mucosa barrier, reducing the production and release of LPS, inhibiting the activation of NLRP3/ASC/Caspase-1 signaling pathway, and repressing renal inflammatory.

A critical review on intestinal mucosal barrier protection effects of dietary polysaccharides.

Studies have shown that dietary polysaccharides, which are widely present in natural foods, have an important impact on the intestinal mucosal barrier. Dietary polysaccharides can maintain the intestinal barrier function through multiple mechanisms. The intestinal barrier is composed of mechanical, chemical, immune, and biological barriers, and dietary polysaccharides, as a bioactive component, can promote and regulate these four barriers. Dietary polysaccharides can enhance the expression of tight junction proteins and mucins such as occludin-1 and zonula occludens-1 (ZO-1) between intestinal epithelial cells, inhibit inflammatory response and oxidative stress, increase the growth of beneficial bacteria, produce beneficial metabolites such as short chain fatty acids (SCFAs), and promote the proliferation and metabolism of immune cells. Given the critical role of the intestinal mucosal system in health and disease, the protective effects of dietary polysaccharides may be potentially valuable for the prevention and treatment of gut-related diseases. Therefore, it is of great significance to further study the mechanism and application prospects of the intestinal mucosal barrier derived from plant, animal, fungal and bacterial sources.

The Role of High Mobility Group Box B-1 in the Prognosis of Colorectal Cancer Based on the Changes in the Intestinal Mucosal Barrier.

Background: To investigate the expression of high mobility group box B-1 (HMGB-1) in patients with colorectal cancer (CRC) and its association with clinicopathological features and prognosis in colorectal carcinoma by combining bioinformatics and clinical data analysis, and to clarify the role of HMGB-1. To examine whether HMGB-1 expression is related to the damage of the intestinal mucosal barrier, and then explore the potential HMGB-1-dependent mechanisms affecting the progression of CRC. Methods: CRC datasets of GSE12945, GSE17536, and GSE17537 from the public gene chip database were screened and downloaded. Clinical information and CRC tissue samples from patients with stage I-III CRC from the hospital were collected. Serum samples of patients were applied by enzyme-linked immunosorbent assay on HMGB-1, and were divided into high and low HMGB-1 expression, which was examined by 16S rDNA sequencing. Immunohistochemistry was performed to examine the relationship between the expression of HMGB-1 and tight junction protein, occludin, tumor necrosis factor-α, and interferon-γ. Results: Based on the Cutoff value of 10.24 ng/mL, the CRC patients were divided into high and low expression groups. In the HMGB-1H patient group, the TNM staging, overall survival, disease-free survival, recurrence, and metastasis were inferior to the HMGB-1L group. The results of 16S rDNA sequencing demonstrated that the Providencia genus was found to be enriched in the HMGB-1L group. Immunohistochemical results showed that HMGB-1 expression was negatively correlated with the expression of ZO-1 and occludin (R = 0.035, R = 0.003, P < .05), but was positively correlated with the expression of TNF-α and IFN-γ (R = 0.016, R = 0.001, P < .05). Conclusion: The survival of CRC patients with positive HMGB-1 expression was significantly shortened, which may be related to the decrease of Rovitensis content, the decreased expression of ZO-1 and occludin, and the increased levels of TNF-α and IFN-γ, which in turn damage the intestinal mucosal barrier, leading to the development of CRC.

Glutamine promotes the proliferation of intestinal stem cells via inhibition of TP53-induced glycolysis and apoptosis regulator promoter methylation in burned mice.

Intestinal stem cells (ISCs) play a pivotal role in maintaining intestinal homeostasis and facilitating the restoration of intestinal mucosal barrier integrity. Glutamine (Gln) is a crucial energy substrate in the intestine, promoting the proliferation of ISCs and mitigating damage to the intestinal mucosal barrier after burn injury. However, the underlying mechanism has not yet been fully elucidated. The objective of this study was to explore the mechanism by which Gln facilitates the proliferation of ISCs. A mouse burn model was established to investigate the impact of Gln on intestinal function. Subsequently, crypts were isolated, and changes in TP53-induced glycolysis and apoptosis regulator (TIGAR) expression were assessed using real-time quantitative polymerase chain reaction (RT-qPCR), western blotting, immunohistochemistry, and immunofluorescence. The effects of TIGAR on cell proliferation were validated through CCK-8, EdU, and clonogenicity assays. Furthermore, the effect of TIGAR on Yes-associated protein (YAP) nuclear translocation and ferroptosis was examined by western blotting and immunofluorescence staining. Finally, dot blot analysis and methylation-specific PCR were performed to evaluate the effect of Gln on TIGAR promoter methylation. The mRNA and protein levels of TIGAR decreased after burn injury, and supplementation with Gln increased the expression of TIGAR. TIGAR accelerates the nuclear translocation of YAP, thereby increasing the proliferation of ISCs. Concurrently, TIGAR promotes the synthesis of nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione to suppress ferroptosis in ISCs. Subsequent investigations demonstrated that Gln inhibits TIGAR promoter methylation by increasing the expression of the demethylase ten-eleven translocation. This change increased TIGAR transcription, increased NADPH synthesis, and reduced oxidative stress, thereby facilitating the restoration of intestinal mucosal barrier integrity post-burn injury. Our data confirmed the inhibitory effect of Gln on TIGAR promoter methylation, which facilitates YAP translocation into the nucleus and suppresses ferroptosis, ultimately promoting the proliferation of ISCs.

MiRNAs: a new target for Chinese medicine to repair the intestinal barrier in the treatment of ulcerative colitis.

Ulcerative colitis (UC) is a chronic nonspecific inflammatory bowel disease whose pathogenesis remains unclear. Dysfunction of the intestinal mucosal barrier is closely related to the pathogenesis of UC, which is characterised by damage to the colon epithelial barrier, disruption of immune homeostasis, and persistent inflammatory cell infiltration. MicroRNAs (miRNAs) exhibit specific or differential expression in both UC animal models and patients, implicating their involvement in the pathogenesis of UC. In recent years there has been progress in using Traditional Chinese medicine (TCM) to regulate miRNA expression for repairing the intestinal mucosal barrier in UC, as demonstrated in animal and cell experiments. However, it has not been applied in a clinical setting and its underlying molecular mechanisms require further investigation. Therefore, this study systematically described the role of miRNAs in UC-induced intestinal barrier damage and the application of TCM to repair this intestinal barrier by regulating miRNA expression, offering new therapeutic targets for UC treatment.

Electroacupuncture protects the intestinal mucosal barrier in diarrhea-predominant Irritable Bowel Syndrome rats by regulating the MCs/Tryptase/PAR-2/MLCK pathway.

The pathogenesis of diarrhea-predominant irritable bowel syndrome (IBS-D) is related to damage to the intestinal mucosal barrier function. Based on the Mast cell (MC)/Tryptase/Protease-activated receptor-2 (PAR-2)/Myosin light chain kinase (MLCK) pathway, this study explored the effect of electroacupuncture (EA) on IBS-D rats and its possible mechanism of protecting the intestinal mucosal barrier. The IBS-D rat model was established by mother-offspring separation, acetic acid enema, and chronic restraint stress. The efficacy of EA on IBS-D rats was evaluated by observing the rate of loose stool (LSP) and the minimum volume threshold of abdominal withdrawal reflex (AWR) in rats. Mast cells and the ultrastructure of intestinal mucosa were observed by H&E staining, toluidine blue staining, and transmission electron microscopy. The expression levels of Tryptase, PAR-2, MLCK, zonula occludens-1 (ZO-1), and Occludin in rats were detected by ELISA, qRT-PCR, and western blot. After 7 days of intervention, compared to the IBS-D group, the loose stool rates of rats in IBS-D + EA group and IBS-D + ketotifen group were decreased (P < 0.01), the minimum volume thresholds of AWR were improved (P < 0.01), the inflammation of colon tissue decreased, the number of MCs were decreased (P < 0.01), the expression of Tryptase, PAR-2, and MLCK were lowered (P < 0.01, P < 0.05), and the expression of ZO-1 and Occludin were enhanced (P < 0.01, P < 0.05). Compared to the EA group, there was no significant difference in each index between the ketotifen groups (P > 0.05). EA has a good therapeutic effect on IBS-D rats. Regulating the MCs/Tryptase/PAR-2/MLCK pathway may be a mechanism to protect the intestinal mucosal barrier.

Pickle water ameliorates castor oil-induced diarrhea in mice by regulating the homeostasis of the gut microbiota and intestinal mucosal barrier.

Diarrhea is a common clinical condition that can potentially be fatal. Current treatment options often have side effects, such as constipation and vomiting, and there remains a need for more effective therapies. Pickled vegetables, a famous traditional food in China, have been suggested in clinical studies to alleviate diarrhea in children, particularly through the use of pickle water (PW). However, the pharmacological effects and mechanisms of PW on intestinal health remain unclear. This study aimed to explore the protective effects of PW on castor oil-induced diarrhea in ICR mice and to investigate its potential mechanisms. To evaluate the antidiarrheal effects of PW, we used a castor oil-induced diarrhea model in ICR mice. Various indices were measured to assess the severity of diarrhea. After euthanizing the mice, oxidative stress markers in the ileum were assessed using biochemical methods, and the expression of tight junction-related proteins in the ileum was analyzed using Western blot. Additionally, 16S rRNA high-throughput sequencing was used to evaluate the diversity and composition of the intestinal flora. The results showed that PW supplementation reduced body weight without significantly affecting organ index and liver function in the castor oil-induced diarrhea mice. PW also effectively reduced the dilution rate, diarrhea index, average loose stool grade, propelling distance of carbon powder, and intestinal propulsive rate while improving the pathological abnormality in the ileum. Furthermore, PW enhanced the activities of total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-PX), and catalase (CAT) while reducing malonaldehyde (MDA) levels. PW also increased the expression of tight junction proteins zonula occludens-1 (ZO-1) and occludin in the ileum. Additionally, the analysis of 16S rDNA revealed that PW increased both α and β diversity, improved the composition of the intestinal flora, and restored it to a normal level. Collectively, dietary PW administration ameliorates Castor oil-induced diarrhea by restoring tight junctions between intestinal mucosal cells, suppressing oxidative stress, and regulating the composition of intestinal flora. These findings suggest that PW may be a promising strategy for managing diarrhea.

Milk-derived Lactobacillus with high production of short-chain fatty acids relieves antibiotic-induced diarrhea in mice.

Antibiotic-associated diarrhea (AAD) is a common side effect during antibiotic treatment, and this has warranted research into alternative protocols. In this study, we investigated the potential therapeutic effects of three cohorts, Lactobacillus plantarum KLDS 1.0386, Lactobacillus acidophilus KLDS 1.0901 and a mixed strain of both, on intestinal inflammation, the intestinal mucosal barrier, and microbial community in mice with ampicillin-induced diarrhea. The results showed that Lactobacillus inhibited the activation of the TLR4/NF-κB signaling pathway, decreased the expression of pro-inflammatory cytokines, increased the expression of anti-inflammatory cytokines in the murine intestine, and alleviated the intestinal barrier damage and inflammation induced by ampicillin. In addition, Lactobacillus ameliorates intestinal epithelial barrier damage by increasing the expression of tight junction proteins and aquaporins. After Lactobacillus treatment, the diversity of gut microbiota increased significantly, and the composition and function of gut microbiota gradually recovered. In the gut microbiota, Bacteroidetes and Escherichia Shigella related to the synthesis of short-chain fatty acids (SCFAs) were significantly affected by ampicillin, while Lactobacillus regulates the cascade of the microbial-SCFA signaling pathway, which greatly promoted the generation of SCFAs. Collectively, Lactobacillus showed better results in treating AAD, especially in mixed strains.