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Autophagy is responsible for the bulk degradation of cytosolic constituents and plays an essential role in the intestinal epithelium by controlling beneficial host–bacterial relationships. Atg5 and Atg7 are thought to be critical for autophagy. However, Atg5 - or Atg7 -deficient cells still form autophagosomes and autolysosomes, and are capable of removing proteins or bacteria. Here, we report that human TRIM31 (tripartite motif), an intestine-specific protein localized in mitochondria, is essential for promoting lipopolysaccharide-induced Atg5/Atg7-independent autophagy. TRIM31 directly interacts with phosphatidylethanolamine in a palmitoylation-dependent manner, leading to induction of autolysosome formation. Depletion of endogenous TRIM31 significantly increases the number of intestinal epithelial cells containing invasive bacteria. Crohn’s disease patients display TRIM31 downregulation. Human cytomegalovirus-infected intestinal cells show a decrease in TRIM31 expression as well as a significant increase in bacterial load, reversible by the introduction of wild-type TRIM31. We provide insight into an alternative autophagy pathway that protects against intestinal pathogenic bacterial infection. While non-canonical, Atg5/Atg7-independent autophagy has been reported to occur, molecular details of alternative autophagy pathways remain unknown. Here, the authors report that the protein TRIM31 mediates alternative autophagy in intestinal cells, which protects against pathogenic bacteria.

Intestinal epithelial cells are adapted in mucosal hypoxia and hypoxia-inducible factors in these cells can fortify barrier integrity to support mucosal tissue healing. Here we investigated whether hypoxia-related pathways could be proposed as potential therapeutic targets for inflammatory bowel disease. We developed a novel hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor, CG-598 which stabilized HIF-1α in the gut tissue. Treatment of CG-598 did not affect extra-intestinal organs or cause any significant adverse effects such as erythropoiesis. In the experimental murine colitis model, CG-598 ameliorated intestinal inflammation with reduction of inflammatory lesions and pro-inflammatory cytokines. CG-598 treatment fortified barrier function by increasing the expression of intestinal trefoil factor, CD73, E-cadherin and mucin. Also, IL-10 and IL-22 were induced from lamina propria CD4 + T-cells. The effectiveness of CG-598 was comparable to other immunosuppressive therapeutics such as TNF-blockers or JAK inhibitors. These results suggest that CG-598 could be a promising therapeutic candidate to treat inflammatory bowel disease.

Intestinal Behçet’s disease (BD) and Crohn’s disease (CD) present similar manifestations, but there are no specific diagnostic tests to differentiate them. We used a proteomic approach to discover novel diagnostic biomarkers specific to intestinal BD. Colon mucosa tissue samples were obtained from patients with intestinal BD or CD using colonoscopy-guided biopsy of the affected bowel. Peptides from seven intestinal BD and seven CD patients were extracted and labeled using tandem mass tag (TMT) reagents. The labeled peptides were identified and quantified using liquid chromatography-tandem mass spectrometry (LC–MS/MS). The proteins were further validated using immunohistochemical (IHC) analysis with tissue samples and an ELISA test with serum samples from 20 intestinal BD and 20 CD patients. Using TMT/LC–MS/MS-based proteomic quantification, we identified 39 proteins differentially expressed between intestinal BD and CD. Beta-2 glycoprotein 1 (APOH) and maltase-glucoamylase (MGAM) showed higher intensity in the IHC staining of intestinal BD tissues than in CD tissues. The serum MGAM level was higher in intestinal BD patients. Proteomic analysis revealed that some proteins were differentially expressed in patients with intestinal BD compared with those with CD. Differential MGAM expression in intestinal BD suggests its role as a potential novel diagnostic biomarker.

Introduction: The impact of device-assisted enteroscopy (DAE) on long-term rebleeding in patients with obscure gastrointestinal bleeding (OGIB) exhibiting detectable small-bowel lesions remains unclear. We investigated the long-term rebleeding rate and predictive factors for DAE in patients with OGIB. Method: Patients with OGIB with small bowel lesions detected through DAE were enrolled at three Korean tertiary hospitals. Predictive risk factors associated with rebleeding were analyzed using the Cox regression analysis. Results: From April 2008 to April 2021, 141 patients were enrolled, including 38 patients (27.0%) with rebleeding. The rebleeding rates at 1, 2, and 3 years were 25.0%, 29.6%, and 31.1%, respectively. The Cox regression analysis revealed that multiple small-bowel lesions (hazard ratio [HR]: 2.551, 95% confidence interval [CI]: 1.157–5.627, p = 0.020), the need for more than five packed red blood cells (RBC) transfusions (HR: 2.704, 95% CI: 1.412–5.181, p = 0.003), and ulcerative lesions (HR: 1.992, 95% CI: 1.037–3.826, p = 0.039) were positively associated with rebleeding. Therapeutic interventions for patients with detectable lesions, overt bleeding (vs. occult bleeding), comorbidities, and medications were not associated with rebleeding. Conclusion: More than 25% of patients with OGIB having detectable small-bowel lesions had rebleeding. Patients with multiple lesions, a requirement of more than five packed RBC transfusions, and ulcerative lesions were associated with a higher risk of rebleeding.

Microbial dysbiosis has long been postulated to be associated with the pathogenesis of inflammatory bowel disease (IBD). Although evidence supporting the anti-colitic effects of melatonin have been accumulating, it is not clear how melatonin affects the microbiota. Herein, we investigated the effects of melatonin on the microbiome in colitis and identified involvement of Toll-like receptor (TLR) 4 signalling in the effects. Melatonin improved dextran sulfate sodium (DSS)-induced colitis and reverted microbial dysbiosis in wild-type (WT) mice but not in TLR4 knockout (KO) mice. Induction of goblet cells was observed with melatonin administration, which was accompanied by suppression of Il1b and Il17a and induction of melatonin receptor and Reg3β, an antimicrobial peptide (AMP) against Gram-negative bacteria. In vitro , melatonin treatment of HT-29 intestinal epithelial cells promotes mucin and wound healing and inhibits growth of Escherichia coli . Herein, we showed that melatonin significantly increases goblet cells, Reg3β, and the ratio of Firmicutes to Bacteriodetes by suppressing Gram-negative bacteria through TLR4 signalling. Our study suggests that sensing of bacteria through TLR4 and regulation of bacteria through altered goblet cells and AMPs is involved in the anti-colitic effects of melatonin. Melatonin may have use in therapeutics for IBD.

Background: A large proportion of patients with inflammatory bowel disease (IBD) relapse after drug discontinuation despite achieving a stable state of infliximab-induced clinical remission. Resuming the use of the same tumor necrosis factor-alpha (TNF-α) inhibitors in patients who relapse following TNF-α inhibitor discontinuation was suggested as a treatment strategy. We conducted a systematic review and meta-analysis to evaluate the efficacy and safety of infliximab retreatment in patients with IBD. Methods: A systematic literature search to shortlist relevant studies was conducted using the MEDLINE, Embase, CINAHL, and SCOPUS databases for studies published from inception to August 2020. Results: Nine studies were included in the meta-analysis. The pooled clinical remission rate of infliximab retreatment in patients with IBD was 85% (95% confidence interval (CI), 81–89%) for induction treatment and 73% (95% CI, 66–80%) for maintenance treatment. A clinical remission rate following infliximab reintroduction was achieved in a greater proportion of patients with Crohn’s disease (87%; 95% CI, 83–91%) than in those with ulcerative colitis (78%; 95% CI, 61–91%) for induction treatment, but the difference was not statistically significant. Infusion-related reactions after infliximab retreatment occurred in 9% of patients with IBD (95% CI, 3–16%). Conclusion: Infliximab retreatment showed high clinical remission rates with tolerable infusion-related reactions in patients with IBD who achieved remission with initial infliximab treatment but relapsed after its discontinuation. We suggest infliximab as a viable alternative in patients with IBD who previously responded well to infliximab treatment.

Behçet syndrome is a systemic vasculitis with an unknown aetiology affecting the small and large vessels of the venous and arterial systems. The presence of symptom clusters, regional differences in disease expression and similarities with, for example, Crohn’s disease suggest that multiple pathological pathways are involved in Behçet syndrome. These disease features also make formulating disease criteria difficult. Genetic studies have identified HLA-B*51 as a genetic risk factor. However, the low prevalence of HLA-B*51 in many patients with bona fide disease, especially in non-endemic regions, suggests that other factors must also be operative in Behçet syndrome. Despite lacking a clear aetiological mechanism and definition, management of manifestations that include major vascular disease, eye disease and central nervous system involvement has improved with the help of new technology. Furthermore, even with our incomplete understanding of disease mechanisms, the prognoses of patients with Behçet syndrome, including those with eye disease, continue to improve. New treatment options and a better understanding of the underlying pathogenesis for various manifestations of this condition are required to further improve the management of the disease, which will improve patient quality of life. Behçet syndrome is a recurrent multiorgan inflammatory disorder and a systemic vasculitis that predominantly affects veins. This Primer reviews the epidemiology, pathophysiology, diagnosis and treatment of Behçet syndrome and describes its effect on patient quality of life and the future outlook for the field.

The cortical actin cytoskeleton plays a critical role in maintaining intestinal epithelial integrity, and the loss of this architecture leads to chronic inflammation, as seen in inflammatory bowel disease (IBD). However, the exact mechanisms underlying aberrant actin remodeling in pathological states remain largely unknown. Here, we show that a subset of patients with IBD exhibits substantially higher levels of tripartite motif-containing protein 40 ( TRIM40 ), a gene that is hardly detectable in healthy individuals. TRIM40 is an E3 ligase that directly targets Rho-associated coiled-coil-containing protein kinase 1 (ROCK1), an essential kinase involved in promoting cell-cell junctions, markedly decreasing the phosphorylation of key signaling factors critical for cortical actin formation and stabilization. This causes failure of the epithelial barrier function, thereby promoting a long-lived inflammatory response. A mutant TRIM40 lacking the RING, B-box, or C-terminal domains has impaired ability to accelerate ROCK1 degradation-driven cortical actin disruption. Accordingly, Trim40 -deficient male mice are highly resistant to dextran sulfate sodium (DSS)-induced colitis. Our findings highlight that aberrant upregulation of TRIM40 , which is epigenetically silenced under healthy conditions, drives IBD by subverting cortical actin formation and exacerbating epithelial barrier dysfunction. The cortical actin cytoskeleton plays a role in maintaining intestinal epithelial integrity. Here the authors report that TRIM40, an E3 ligase, disrupts cortical actin formation and leads to loss of epithelial barrier integrity, and that genetic loss of TRIM40 is protective against experimental colitis in male mice.

Background As digital healthcare solutions evolve, mobile applications (apps) have become essential tools for managing chronic conditions. Inflammatory Bowel Disease (IBD), including Crohn’s disease and ulcerative colitis, is a chronic, rare disease that requires lifelong management. Mobile apps can help IBD patients by providing tools for self-monitoring and improving shared decision-making with healthcare professionals. Objective This study aimed to develop a digital healthcare app specifically designed to meet the unique needs of IBD patients. The app sought to enhance self-management capabilities while improving the quality of communication between patients and healthcare providers through comprehensive usability evaluations. Methods The study followed a four-step process: (1) Design of six core features based on patient needs and expert feedback; (2) Development of the app’s architecture, database, and interface as an initial concept version, followed by testing and deployment; (3) Heuristic evaluation with 15 experts, a four-week usability test with 20 IBD patients, and focus group interviews to gather feedback; and (4) Refinement and upgrade of the app to version 1.0 based on usability test results and further feedback. Results The results of this study followed these steps: 1. Incorporating feedback from IBD patients and experts, the core features of the app were designed to include a Personalized Health Summary, Symptom Tracking, and Medication Adherence Monitoring using Patient-Reported Outcomes (PROs). 2. A prototype version of \"WITH-Jang\" was developed, integrating these key features and undergoing initial testing. 3. Usability testing was conducted with 15 experts and 20 IBD patients to assess effectiveness and identify areas for improvement. 4. Based on the evaluation results, the app was refined with a simplified and intuitive UI and an updated \"My Health Summary\" page, leading to the release of WITH-Jang 1.0. Conclusions The WITH-Jang app supports proactive self-health management by addressing the core needs of IBD patients. It visualizes symptom and medication data and enhances communication between patients and healthcare providers, enabling personalized care and shared decision-making, making it a valuable tool for chronic disease management. Trial registration KCT0010068, December 19, 2024.

Metformin has been known to suppress cancer stem cells (CSCs) in some cancers. However, the differential effects of metformin on CSCs and their mechanisms have not been reported. Herein, metformin induced pAMPK activation and pS6 suppression in metformin-sensitive (HT29) cells, but not in metformin-resistant (SW620) cells. The oxygen consumption rate was higher in HT29 cells than in SW620 cells and showed a prominent decrease after metformin treatment in HT29 cells. In glutamine-depleted medium, but not in low-glucose medium, SW620 cells became sensitive to the CSC-suppressing effect of metformin. A combination of metformin and glutaminase C inhibitor (compound 968) suppressed CSCs in SW620 cells and enhanced that effect in HT29 cells. SW620 cells showed higher expression of glutaminase 1 and glutamine transporter (ASCT2) than HT29 cells, especially ASCT2 in CSCs. Knockdown of glutaminase 1, ASCT2, and c-Myc induced significant CSC-suppression and enhanced CSC-suppressing effect of metformin and compound 968. In xenografts and human cancer organoids, combined treatment with metformin and compound 968 showed the same results as those shown in vitro . In conclusion, the effect of metformin on CSCs varies depending on the AMPK-mTOR and glutamine metabolism. The inhibition of glutamine pathway could enhance the CSC-suppressing effect of metformin, overcoming metformin resistance.