The Role of β-Carotene in Colonic Inflammation and Intestinal Barrier Integrity.
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ABSTRACT:
SUBMITTER: Cheng J
PROVIDER: S-EPMC8502815 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The protein C (PC) pathway is a well-characterized coagulation system. Endothelial PC receptors and thrombomodulin mediate the conversion of PC to its activated form, a potent anticoagulant and anti-inflammatory molecule. Here we show that the PC pathway is expressed on intestinal epithelial cells. The epithelial expression of PC and endothelial PC receptor is down-regulated In patients with inflammatory bowel disease. PC(-/-)/PC(Tg) mice, expressing only 3% of WT PC, developed spontaneous intestinal inflammation and were prone to severe experimental colitis. These mice also demonstrated spontaneous elevated production of inflammatory cytokines and increased intestinal permeability. Structural analysis of epithelial tight junction molecules revealed that lack of PC leads to decreased JAM-A and claudin-3 expression and an altered pattern of ZO-1 expression. In vitro, treatment of epithelial cells with activated PC led to protection of tight junction disruption induced by TNF-?, and in vivo, topical treatment with activated PC led to mucosal healing and amelioration of colitis. Taken together, these findings demonstrate that the PC pathway is a unique system involved in controlling intestinal homeostasis and inflammation by regulating epithelial barrier function.
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Project description:Epidemiological studies revealed that antibiotics exposure increases a risk of inflammatory bowel diseases (IBD) development. It remained largely unknown how antibiotic-induced dysbiosis confers the risk for enhanced inflammatory response. The aim of the present study was to test the hypothesis that SCFAs, their receptors and transporters mediate the antibiotic long-term effects on the functional state of colonic mucosa and susceptibility to the experimental colitis. Male Wistar rats were treated daily for 14 days with antibiotic ceftriaxone (300 mg/kg, i.m.) or vehicle; euthanized by CO2 inhalation followed by cervical dislocation in 1, 14 or 56 days after antibiotic withdrawal. We found increased cecum weight and sustained changes in microbiota composition after ceftriaxone treatment with increased number of conditionally pathogenic enterobacteria, E. coli, Clostridium, Staphylococcus spp. and hemolytic bacteria even at 56 days after antibiotic withdrawal. The concentration of SCFAs was decreased after ceftriaxone withdrawal. We found decreased immunoreactivity of the FFA2, FFA3 receptors, SMCT1 and increased MCT1 & MCT4 transporters of SCFAs in colon mucosa. These changes evoked a significant shift in colonic mucosal homeostasis: the disturbance of oxidant-antioxidant balance; activation of redox-sensitive transcription factor HIF1? and ERK1/2 MAP kinase; increased colonic epithelial permeability and bacterial translocation to blood; morphological remodeling of the colonic tissue. Ceftriaxone pretreatment significantly reinforced inflammation during experimental colitis 56 days after ceftriaxone withdrawal, which was confirmed by increased histopathology of colitis, Goblet cell dysfunction, colonic dilatation and wall thickening, and increased serum levels of inflammatory cytokines (TNF-? and IL-10). Since the recognition of the importance of microbiota metabolic activity rather than their composition in the development of inflammatory disorders, e.g. IBD, the present study is the first report on the role of the SCFA system in the long lasting side effects of antibiotic treatment and its implication in IBD development.
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Project description:ObjectiveWeaning is an important stage in the life of young mammals, which is associated with intestinal inflammation, gut microbiota disorders, and even death. β-Carotene displays anti-inflammatory and antioxidant activities, which can prevent the development of inflammatory diseases. However, whether β-carotene can affect intestinal microbiota remains unclear.MethodsTwenty-four piglets were distributed into four groups: the normal suckling group (Con), the weaning group (WG), the weaning+β-carotene (40 mg/kg) group (LCBC), and the weaning+β-carotene (80 mg/kg) group (HCBC). The serum, jejunum, colon, and faeces were collected separately from each group. The effects of β-carotene on the phenotype, overall structure, and composition of gut microbiota were assessed in weaning piglets.ResultsThe results showed that β-carotene improved the growth performance, intestinal morphology and relieved inflammation. Furthermore, β-carotene significantly decreased the species from phyla Bacteroidetes and the genus Prevotella, and Blautia, and increased the species from the phyla Firmicutes and the genera p-75-a5, and Parabacteroides compared to the WG group. Spearman's correlation analysis showed that Prevotella and Blautia were positively correlated, and Parabacteroides and Synergistes were negatively correlated with the levels of interleukin-1β (IL-1β), IL-6, and tumour necrosis factor-α (TNF-α), while p-75-a5 showed negative correlation with IL-6 in serum samples from piglets.ConclusionThese findings indicate that β-carotene could alleviate weaning-induced intestinal inflammation by modulating gut microbiota in piglets. Prevotella may be a potential target of β-carotene in alleviating the weaning-induced intestinal inflammation in piglets.
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2024-06-29 | GSE236167 | GEO
Project description:ObjectiveThere is no conclusive evidence for involvement of intestinal barrier alteration in the etiology of anorexia nervosa (AN). The aims of this pilot study were to identify serum markers of intestinal barrier integrity in patients with AN and to determine the relationships between those markers and body mass index (BMI), eating disorder symptoms, gastrointestinal complaints, and liver synthesis function (international normalized ratio [INR]).MethodTwenty-five outpatients with AN prior to starting treatment and 28 healthy controls (HC) were assessed. BMI and serum markers of intestinal barrier integrity were measured, including zonulin family peptides (ZFP), lipopolysaccharide-binding protein (LBP), and intestinal fatty-acid-binding protein (i-FABP). Eating disorder symptoms and gastrointestinal complaints were evaluated via questionnaires.ResultsThe serum ZFP concentration was significantly lower in patients with AN than in HC (44.2 [7.4] vs. 49.2 [5.6] ng/ml, mean [standard deviation], p = .008). LBP and i-FABP did not differ between the two groups. In patients with AN, serum ZFP was significantly predicted by BMI (β = 0.479, p = .009), age (β = 0.411, p = .020), and INR (β = -0.388, p = .028). No such associations were found for either gastrointestinal complaints or eating disorder symptoms.DiscussionAbnormal levels of serum ZFP were observed in patients with AN. Further studies with other assessment methods are warranted to examine intestinal barrier function in AN.Clinical trial registrationClinicalTrials.gov Identifier: NCT02745067.
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Project description:Junctional adhesion molecule-A (JAM-A), an epithelial tight junction protein, plays an important role in regulating intestinal permeability through association with a scaffold signaling complex containing ZO-2, Afadin, and the small GTPase Rap2. Under inflammatory conditions, we report that the cytoplasmic tail of JAM-A is tyrosine phosphorylated (p-Y280) in association with loss of barrier function. While barely detectable Y280 phosphorylation was observed in confluent monolayers of human intestinal epithelial cells under basal conditions, exposure to cytokines TNF?, IFN?, IL-22, or IL-17A, resulted in compromised barrier function in parallel with increased p-Y280. Phosphorylation was Src kinase dependent, and we identified Yes-1 and PTPN13 as a major kinase and phosphatase for p-JAM-A Y280, respectively. Moreover, cytokines IL-22 or IL-17A induced increased activity of Yes-1. Furthermore, the Src kinase inhibitor PP2 rescued cytokine-induced epithelial barrier defects and inhibited phosphorylation of JAM-A Y280 in vitro. Phosphorylation of JAM-A Y280 and increased permeability correlated with reduced JAM-A association with active Rap2. Finally, we observed increased phosphorylation of Y280 in colonic epithelium of individuals with ulcerative colitis and in mice with experimentally induced colitis. These findings support a novel mechanism by which tyrosine phosphorylation of JAM-A Y280 regulates epithelial barrier function during inflammation.
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Project description:Zeolites are crystalline compounds with microporous structures of Si-tetrahedrons. In the gut, these silicates could act as adsorbents, ion-exchangers, catalysts, detergents or anti-diarrheic agents. This study evaluated whether zeolite supplementation affects biomarkers of intestinal wall permeability and parameters of oxidation and inflammation in aerobically trained individuals, and whether it could improve their performance.In a randomized, double-blinded, placebo controlled trial, 52 endurance trained men and women, similar in body fat, non-smokers, 20-50 years, received 1.85 g of zeolite per day for 12 weeks. Stool samples for determination of intestinal wall integrity biomarkers were collected. From blood, markers of redox biology, inflammation, and DNA damage were determined at the beginning and the end of the study. In addition, VO2max and maximum performance were evaluated at baseline and after 12 weeks of treatment. For statistical analyses a 2-factor ANOVA was used.At baseline both groups showed slightly increased stool zonulin concentrations above normal. After 12 weeks with zeolite zonulin was significantly (p?<?0.05) decreased in the supplemented group. IL-10 increased tendentially (p?<?0.1) in the zeolite group. There were no significant changes observed in the other measured parameters.Twelve weeks of zeolite supplementation exerted beneficial effects on intestinal wall integrity as indicated via decreased concentrations of the tight junction modulator zonulin. This was accompanied by mild anti-inflammatory effects in this cohort of aerobically trained subjects. Further research is needed to explore mechanistic explanations for the observations in this study.
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Project description:Proteases constitute the largest enzyme gene family in vertebrates with intracellular and secreted proteases having critical roles in cellular and organ physiology. Intestinal tract contains diverse set of proteases mediating digestion, microbial responses, epithelial and immune signaling. Transit of chyme through the intestinal tract results in significant suppression of proteases. Although endogenous protease inhibitors have been identified, the broader mechanisms underlying protease regulation in the intestinal tract remains unclear. The objective of this study was to determine microbial regulation of proteolytic activity in intestinal tract using phenotype of post-infection irritable bowel syndrome, a condition characterized by high fecal proteolytic activity. Proteases of host pancreatic origin (chymotrypsin like pancreatic elastase 2A, 3B and trypsin 2) drove proteolytic activity. Of the 14 differentially abundant taxa, high proteolytic activity state was characterized by complete absence of the commensal Alistipes putredinis. Germ free mice had very high proteolytic activity (10-fold of specific-pathogen free mice) which dropped significantly upon humanization with microbiota from healthy volunteers. In contrast, high proteolytic activity microbiota failed to inhibit it, a defect that corrected with fecal microbiota transplant as well as addition of A. putredinis. These mice also had increased intestinal permeability similar to that seen in patients. Microbiota β-glucuronidases mediate bilirubin deconjugation and unconjugated bilirubin is an inhibitor of serine proteases. We found that high proteolytic activity patients had lower urobilinogen levels, a product of bilirubin deconjugation. Mice colonized with β-glucuronidase overexpressing E. coli demonstrated significant inhibition of proteolytic activity and treatment with β-glucuronidase inhibitors increased it. The findings establish that specific commensal microbiota mediates effective inhibition of host pancreatic proteases and maintains intestinal barrier function through the production of β-glucuronidases. This suggests an important homeostatic role for commensal intestinal microbiota.
2021-03-11 | ST001718 | MetabolomicsWorkbench