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Plectin, a highly versatile cytolinker protein, provides tissues with mechanical stability through the integration of intermediate filaments (IFs) with cell junctions. Here, we hypothesize that plectin-controlled cytoarchitecture is a critical determinant of the intestinal barrier function and homeostasis. Mice lacking plectin in an intestinal epithelial cell (IEC; PleΔIEC) spontaneously developed colitis characterized by extensive detachment of IECs from the basement membrane (BM), increased intestinal permeability, and inflammatory lesions. Moreover, plectin expression was reduced in the colons of ulcerative colitis (UC) patients and negatively correlated with the severity of colitis. Mechanistically, plectin deficiency in IECs led to aberrant keratin filament (KF) network organization and the formation of dysfunctional hemidesmosomes (HDs) and intercellular junctions. In addition, the hemidesmosomal α6β4 integrin (Itg) receptor showed attenuated association with KFs, and protein profiling revealed prominent downregulation of junctional constituents. Consistent with the effects of plectin loss in the intestinal epithelium, plectin-deficient IECs exhibited remarkably reduced mechanical stability and limited adhesion capacity in vitro. Feeding mice with a low-residue liquid diet that reduced mechanical stress and antibiotic treatment successfully mitigated epithelial damage in the PleΔIEC colon.

Abstract Background Psychiatric comorbidity might modify the disease course adversely in patients with inflammatory bowel disease (IBD). Treatment options include antidepressants, which, apart from improving mood, have anti-inflammatory properties that might modify the disease course. This nationwide study aimed to examine the influence of antidepressants on the disease course among patients with ulcerative colitis (UC) and Crohn's disease (CD). Methods Patients registered with an incident diagnosis of CD or UC in the Danish National Patient Register (2000-2017) were included. Information on antidepressant use and proxy measures of disease activity (health care and drug utilization) was extracted from national population registers. Poisson regression was performed to estimate disease activity rates by antidepressant use adjusted for confounders. Furthermore, the analyses were performed stratified by IBD subtype and type of antidepressants. Results A total of 42,890 patients were included (UC: 69.5%; CD: 30.5%). When adjusted for confounders, a lower incidence rate of disease activity was found among antidepressant users compared with nonusers in both CD (incidence rate ratio [IRR], 0.75; 95% confidence interval [CI], 0.68-0.82) and UC (IRR, 0.90; 95% CI, 0.84-0.95) patients. Further, markedly lower rates of disease activity were found among CD (IRR, 0.51; 95% CI, 0.43-0.62) and UC (IRR, 0.67; 95% CI, 0.59-0.75) patients with no use of antidepressants before IBD onset. Conclusions In this nationwide study, antidepressant use was found to be beneficial on the disease course among patients with UC and CD, particularly in patients with no use of antidepressants before IBD onset. Randomized controlled trials are warranted to investigate the potential of antidepressants being an adjunct treatment to conventional IBD therapy.

Loss of the colonic inner mucus layer leads to spontaneously severe colitis and colorectal cancer. However, key host factors that may control the generation of the inner mucus layer are rarely reported. Here, we identify a novel function of TRIM34 in goblet cells (GCs) in controlling inner mucus layer generation. Upon DSS treatment, TRIM34 deficiency led to a reduction in Muc2 secretion by GCs and subsequent defects in the inner mucus layer. This outcome rendered TRIM34-deficient mice more susceptible to DSS-induced colitis and colitis-associated colorectal cancer. Mechanistic experiments demonstrated that TRIM34 controlled TLR signaling-induced Nox/Duox-dependent ROS synthesis, thereby promoting the compound exocytosis of Muc2 by colonic GCs that were exposed to bacterial TLR ligands. Clinical analysis revealed that TRIM34 levels in patient samples were correlated with the outcome of ulcerative colitis (UC) and the prognosis of rectal adenocarcinoma. This study indicates that TRIM34 expression in GCs plays an essential role in generating the inner mucus layer and preventing excessive colon inflammation and tumorigenesis.

Background/Aims: The primary therapeutic goals in ulcerative colitis (UC) are to maintain excellent quality of life (QOL) by treating flare-ups when they occur, and preventing flare-ups. Since stress can trigger UC flare-ups, we investigated the efficacy of mindfulness-based stress reduction (MBSR) to reduce flare-ups and improve QOL. Methods: Patients with moderately severe UC, in remission, were randomized to MBSR or time/attention control. Primary outcome was disease status. Secondary outcomes were changes in markers of inflammation and disease activity, markers of stress and psychological assessments. Results: 55 subjects were randomized. Absence of flares, time to flare and severity of flare over 1 year were similar between the two groups. However, post hoc analysis showed that MBSR decreased the proportion of participants with at least one flare-up among those with top tertile urinary cortisol and baseline perceived stress (30 vs. 70%; p < 0.001). MBSR patients who flared demonstrated significantly lower stress at the last visit compared to flared patients in the control group (p = 0.04). Furthermore, MBSR prevented a drop in the Inflammatory Bowel Disease Quality of Life Questionnaire during flare (p < 0.01). Conclusion: MBSR did not affect the rate or severity of flare-ups in UC patients in remission. However, MBSR might be effective for those with high stress reactivity (high perceived stress and urinary cortisol) during remission. MBSR appears to improve QOL in UC patients by minimizing the negative impact of flare-ups on QOL. Further studies are needed to identify a subset of patients for whom MBSR could alter disease course.

Innate lymphoid cells (ILCs) and CD4 + T cells produce IL-22, which is critical for intestinal immunity. The microbiota is central to IL-22 production in the intestines; however, the factors that regulate IL-22 production by CD4 + T cells and ILCs are not clear. Here, we show that microbiota-derived short-chain fatty acids (SCFAs) promote IL-22 production by CD4 + T cells and ILCs through G-protein receptor 41 (GPR41) and inhibiting histone deacetylase (HDAC). SCFAs upregulate IL-22 production by promoting aryl hydrocarbon receptor (AhR) and hypoxia-inducible factor 1α (HIF1α) expression, which are differentially regulated by mTOR and Stat3. HIF1α binds directly to the Il22 promoter, and SCFAs increase HIF1α binding to the Il22 promoter through histone modification. SCFA supplementation enhances IL-22 production, which protects intestines from inflammation. SCFAs promote human CD4 + T cell IL-22 production. These findings establish the roles of SCFAs in inducing IL-22 production in CD4 + T cells and ILCs to maintain intestinal homeostasis. Intestinal IL-22 has important regulatory effects on the barrier and intestinal diseases and its production is controlled by the intestinal microbiome. Here the authors show that intestinal immune cell production of IL-22 is regulated by short chain fatty acids via an aryl hydrocarbon receptor and HIF1α-mediated mechanism that protects mice from intestinal inflammation.

Abstract Background Alterations in the gut microbiota are strongly associated with the development of inflammatory bowel disease (IBD), particularly with Crohn's disease, which is characterized by reduced abundance of commensal anaerobic bacteria including members of the Bacteroides genus. Our aim was to investigate the protective effects of Bacteroides thetaiotaomicron, an abundant member of this genus, in different rodent models of IBD. Methods We assessed the effect of B. thetaiotaomicron administration on primary readouts of colitis (weight loss, histopathology, and immune parameters) in dextran sodium sulphate (DSS) and interleukin-10 knockout (IL10KO) models of IBD. Efficacy of a freeze-dried bacterial formulation and a purified recombinant protein of B. thetaiotaomicron was also investigated. Results B. thetaiotaomicron showed protective effects in both DSS and IL10KO rodent models, as demonstrated by significant amelioration of weight loss, colon shortening, histopathological damage and immune activation. This efficacy was not exclusive to actively growing bacterial preparations but was retained by freeze-dried cells of B. thetaiotaomicron. A pirin-like protein (PLP) of B. thetaiotaomicron, identified by microarray analysis during coculture of the bacterial strain with Caco-2 cells, reduced pro-inflammatory NF-κB signalling in these intestinal epithelial cells. Recombinant PLP partially recapitulated the effect of the whole strain in a rat DSS model. Conclusions B. thetaiotaomicron displays strong efficacy in preclinical models of IBD and protects against weight loss, histopathological changes in the colon and inflammatory markers. These data indicate that the live strain or its products may be a novel alternative to current treatment options for Crohn's disease.

As traditional methods have become increasingly difficult, the Internet offers a mechanism for conducting survey research quickly and efficiently. However, the validity of this research depends on the ability of respondents to accurately report health status. We used a large Internet-based inflammatory bowel disease (IBD) cohort to validate self-reported IBD against physician reports.MethodsBetween June 22, 2012, and April 01, 2013, all participants of CCFA Partners (n = 6681) were invited to participate, and 450 were selected by random stratified sampling. We sent physicians a survey to confirm IBD diagnosis and characteristics. We used descriptive statistics to compare data.ResultsA total of 4423 participants (66%) indicated interest. Of 450 selected, 261 (58%) consented, and physician reports were obtained for 184 (71%). Physicians confirmed IBD status in 178 (97%) and type in 171 (97% of confirmed). The matching between patient and physician reports for Crohn's disease (CD) was 82% for disease location, 89% for the presence of perianal disease, and 46% for disease behavior. For ulcerative colitis (UC), disease location matched 54% of the time. Physician reports confirmed the status of ever having bowel surgery for 97% of CD and 94% for UC and confirmed current pouch or ostomy in 84% of CD and 81% of UC.ConclusionsSelf-reported IBD in CCFA Partners is highly accurate, and participants are willing to release medical records for research. Self-reported phenotypic characteristics were less valid. The validity of IBD diagnoses among the participants of CCFA Partners supports the use of this cohort for patient-centered outcome research.

A fraction of the intestinal microbiota as precise as a single bacterial species confers infection resistance by synthesizing Clostridium difficile -inhibiting metabolites from host-derived bile salts. Gut bacteria providing resistance to Clostridium difficile Antibiotic treatment can kill many members of the normal commensal gut microbiota, leaving patients susceptible to intestinal infection. Among infections that can result from antibiotic-mediated commensal flora destruction, Clostridium difficile colitis is one of the most common and difficult to treat. Eric Pamer and colleagues screened the mouse microbiota with a panel of antibiotics and looked for distinct microbiota changes associated with susceptibility to C. difficile . They identified resistance-associated microbiota constituents common to mice and humans, including Clostridium scindens , which they show confers resistance to infection by synthesizing C. difficile -inhibiting metabolites from host-derived bile salts. These findings could point the way towards novel approaches to the treatment and prevention of C. difficile colitis such as replenishment of secondary bile acids or biosynthesis-competent bacteria as adjuncts to faecal microbiota transplants. The gastrointestinal tracts of mammals are colonized by hundreds of microbial species that contribute to health, including colonization resistance against intestinal pathogens 1 . Many antibiotics destroy intestinal microbial communities and increase susceptibility to intestinal pathogens 2 . Among these, Clostridium difficile , a major cause of antibiotic-induced diarrhoea, greatly increases morbidity and mortality in hospitalized patients 3 . Which intestinal bacteria provide resistance to C. difficile infection and their in vivo inhibitory mechanisms remain unclear. Here we correlate loss of specific bacterial taxa with development of infection, by treating mice with different antibiotics that result in distinct microbiota changes and lead to varied susceptibility to C. difficile . Mathematical modelling augmented by analyses of the microbiota of hospitalized patients identifies resistance-associated bacteria common to mice and humans. Using these platforms, we determine that Clostridium scindens , a bile acid 7α-dehydroxylating intestinal bacterium, is associated with resistance to C. difficile infection and, upon administration, enhances resistance to infection in a secondary bile acid dependent fashion. Using a workflow involving mouse models, clinical studies, metagenomic analyses, and mathematical modelling, we identify a probiotic candidate that corrects a clinically relevant microbiome deficiency. These findings have implications for the rational design of targeted antimicrobials as well as microbiome-based diagnostics and therapeutics for individuals at risk of C. difficile infection.

Emerging research supports that triclosan (TCS), an antimicrobial agent found in thousands of consumer products, exacerbates colitis and colitis-associated colorectal tumorigenesis in animal models. While the intestinal toxicities of TCS require the presence of gut microbiota, the molecular mechanisms involved have not been defined. Here we show that intestinal commensal microbes mediate metabolic activation of TCS in the colon and drive its gut toxicology. Using a range of in vitro, ex vivo, and in vivo approaches, we identify specific microbial β-glucuronidase (GUS) enzymes involved and pinpoint molecular motifs required to metabolically activate TCS in the gut. Finally, we show that targeted inhibition of bacterial GUS enzymes abolishes the colitis-promoting effects of TCS, supporting an essential role of specific microbial proteins in TCS toxicity. Together, our results define a mechanism by which intestinal microbes contribute to the metabolic activation and gut toxicity of TCS, and highlight the importance of considering the contributions of the gut microbiota in evaluating the toxic potential of environmental chemicals. Triclosan (TCS), an antimicrobial agent commonly found in consumer products, has been reported to exacerbates colitis in animal models. Here, using in vitro and in vivo approaches, the authors show that gut bacterial enzymes can drive the metabolic activation and gut toxicity of TCS, highlighting an important role of intestinal microbial factors in the complex etiology of colitis.

Radiation-induced acute intestinal symptoms (RIAISs) are the most relevant complication of abdominal or pelvic radiation. Considering the negative impact of RIAIS on patients’ daily activities, the preventive effects of berberine on RIAIS in patients were investigated. Thirty-six patients with seminoma or lymphomas were randomized to receive berberine oral ( n  = 18) or not ( n  = 18). Forty-two patients with cervical cancer were randomized to a trial group ( n  = 21) and control group ( n  = 21). Radiotherapy used a parallel opposed anterior and posterior. 300-mg berberine was administered orally three times daily in trial groups. Eight patients with RIAIS were treated with 300-mg berberine three times daily from the third to the fifth week. Toxicities, such as fatigue, anorexia/nausea, etc., were graded weekly according to CTC version 2.0. Patients with abdominal/pelvic radiation in the control group showed grade 1 fatigue, anorexia/nausea, colitis, vomiting, proctitis, weight loss, diarrhea and grade 2 anorexia/nausea, fatigue. Only grade 1 colitis, anorexia/nausea, and fatigue were seen in patients of abdominal radiation treated with berberine. Grade 1 fatigue, colitis, anorexia/nausea, and proctitis occurred in patients of pelvic radiotherapy treated with berberine. Pretreatment with berberine significantly decreased the incidence and severity of RIAIS in patients with abdominal/pelvic radiotherapy when compared with the patients of the control group ( P  < 0.05). RIAIS were reduced in patients with abdominal radiotherapy/pelvic radiation after receiving berberine treatment. Berberine significantly reduced the incidence and severity of RIAIS and postponed the occurrence of RIAIS in patients with abdominal or whole pelvic radiation.