Therapeutic Target In Ulcerative Colitis Research Articles

Neutrophil extracellular traps induce barrier dysfunction in DSS-induced ulcerative colitis via the cGAS-STING pathway

Peptidyl arginine deiminase 4 (PAD4)-mediated neutrophil extracellular traps (NETs) play a crucial role in the pathogenesis of ulcerative colitis (UC). The cGAS-STING intracellular DNA-sensing pathway has been recognized as a pivotal mediator of inflammation. This study aimed to explore how NETs contribute to intestinal inflammation and barrier dysfunction in UC, focusing on the cGAS-STING pathway. We observed a significant increase of STING expression in UC mouse colons, which was mitigated by blocking NET formation through PAD4 genetic knockout. Moreover, NETs were discovered to activate the cGAS-STING pathway in MC38 cells in a dose and time-dependent manner, leading to the secretion of inflammatory cytokines and impaired barrier function. Additionally, STING deficiency ameliorated the clinical colitis index, intestinal inflammation, and barrier dysfunction. These findings underscore the involvement of cGAS-STING in regulating NET-mediated intestinal inflammation, suggesting its potential as a novel therapeutic target for UC.

Activation of AMPK/SIRT1/FOXO3a signaling by BMS-477118 (saxagliptin) mitigates chronic colitis in rats: uncovering new anti-inflammatory and antifibrotic roles.

Ulcerative colitis (UC) is a debilitating chronic disease marked by persistent inflammation and intestinal fibrosis. Despite the availability of various treatments, many patients fail to achieve long-term remission, underscoring a significant unmet therapeutic need. BMS-477118, a reversible inhibitor of dipeptidyl peptidase 4 (DPP4), has demonstrated anti-inflammatory properties in preclinical and clinical studies with minimal adverse effects compared to other antidiabetic agents. However, the potential benefits of BMS-477118 in chronic UC have not yet been explored. In this study, we aimed to investigate the effects of BMS-477118 in rats subjected to chronic dextran sodium sulfate (DSS) administration. Our findings indicate that BMS-477118 activates the interconnected positive feedback loop involving AMPK, SIRT1, and FOXO3a, improving histological appearance in injured rat colons. BMS-477118 also reduced fibrotic changes associated with the chronic nature of the animal model, alleviated macroscopic damage and disease severity, and improved the colon weight-to-length ratio. Additionally, BMS-477118 prevented DSS-induced weight loss and enhanced tight junction proteins. These effects, in conjunction with reduced oxidative stress and its potential anti-inflammatory, antiapoptotic, and autophagy-inducing properties, fostered prolonged survival in rats with chronic UC. To conclude, BMS-477118 has the potential to activate the AMPK/SIRT1/FOXO3a signaling pathway in inflamed colons. These results suggest that the AMPK/SIRT1/FOXO3a pathway could be a new therapeutic target for UC. Further research is mandatory to explore the therapeutic possibilities of this pathway. Additionally, continued studies on the therapeutic potential of BMS-477118 and other DPP4 inhibitors are promising for creating new treatments for various conditions, including UC in diabetic patients.

Histologic improvement predicts endoscopic remission in patients with ulcerative colitis

Limited research has been performed to determine if histologic improvement serves as a prognosticator for endoscopic remission, a key therapeutic target for ulcerative colitis (UC). The primary aim of the study was to evaluate if histological activity could predict endoscopic remission in UC patients with Mayo endoscopic subscores (MES) of 0 or 1. In addition, we compared the clinical outcomes between histologic improvement group and active group. This research encompassed 492 individuals with UC with MES of 0 or 1, who underwent histological assessment as per the established protocol of Samsung Medical Center between January 2018 and December 2020. Participants were categorized into two cohorts based on the degree of histological activity: those showing histologic improvement and those with ongoing histologic activity. The endoscopic activity was assessed during follow-up, and the primary outcome was endoscopic remission according to histologic activity. Out of the total participants, endoscopic activity was scrutinized in 435 patients during the colonoscopic follow-up and in 146 during the subsequent one. The histologic improvement group at the index colonoscopy was more likely achieve endoscopic remission than the histologic active group. Clinical relapse was more likely in the histologic active group than in the histologic improvement group.

Dynamic changes in the gut microbiota composition during adalimumab therapy in patients with ulcerative colitis: implications for treatment response prediction and therapeutic targets

BackgroundWhile significant research exists on gut microbiota changes after anti-tumor necrosis factor-alpha (anti TNF-α) therapy for ulcerative colitis, little is known about the longitudinal changes related to the effects of anti TNF-α. This study aimed to investigate the dynamics of gut microbiome changes during anti TNF-α (adalimumab) therapy in patients with ulcerative colitis (UC).ResultsThe microbiota composition was affected by the disease severity and extent in patients with UC. Regardless of clinical remission status at each time point, patients with UC exhibited microbial community distinctions from healthy controls. Distinct amplicon sequence variants (ASVs) differences were identified throughout the course of Adalimumab (ADA) treatment at each time point. A notable reduction in gut microbiome dissimilarity was observed only in remitters. Remitters demonstrated a decrease in the relative abundances of Burkholderia-Caballeronia-Paraburkholderia and Staphylococcus as the treatment progressed. Additionally, there was an observed increase in the relative abundances of Bifidobacterium and Dorea. Given the distribution of the 48 ASVs with high or low relative abundances in the pre-treatment samples according to clinical remission at week 8, a clinical remission at week 8 with a sensitivity and specificity of 72.4% and 84.3%, respectively, was predicted on the receiver operating characteristic curve (area under the curve, 0.851).ConclusionsThe gut microbiota undergoes diverse changes according to the treatment response during ADA treatment. These changes provide insights into predicting treatment responses to ADA and offer new therapeutic targets for UC.

The emerging role of neutrophil extracellular traps in ulcerative colitis.

Ulcerative colitis (UC) is characterized by chronic non-recessive inflammation of the intestinal mucosa involving both innate and adaptive immune responses. Currently, new targeted therapies are urgently needed for UC, and neutrophil extracellular traps (NETs) are new therapeutic options. NETs are DNA-based networks released from neutrophils into the extracellular space after stimulation, in which a variety of granule proteins, proteolytic enzymes, antibacterial peptides, histones, and other network structures are embedded. With the deepening of the studies on NETs, their regulatory role in the development of autoimmune and autoinflammatory diseases has received extensive attention in recent years. Increasing evidence indicates that excess NETs exacerbate the inflammatory response in UC, disrupting the structure and function of the intestinal mucosal barrier and increasing the risk of thrombosis. Although NETs are usually assigned a deleterious role in promoting the pathological process of UC, they also appear to have a protective role in some models. Despite such progress, comprehensive reviews describing the therapeutic promise of NETs in UC remain limited. In this review, we discuss the latest evidence for the formation and degradation of NETs, focusing on their double-edged role in UC. Finally, the potential implications of NETs as therapeutic targets for UC will be discussed. This review aims to provide novel insights into the pathogenesis and therapeutic options for UC.

Modified Zhenwu Decoction improved intestinal barrier function of experimental colitis through activation of sGC-mediated cGMP/PKG signaling

BackgroundThe invasion of luminal antigens and an aberrant immune response resulting from a disrupted physical epithelial barrier are the key characteristics of ulcerative colitis (UC). The restoration of damaged epithelial function is crucial for maintaining mucosal homeostasis and disease quiescence. Current therapies for UC primarily focus on suppressing inflammation. However, most patients fail to respond to therapy or develop secondary resistance over time, emphasizing the need to develop novel therapeutic targets for UC. Our study aimed to identify the potential targets of a novel modified herbal formula from the Zhen Wu Decoction, namely CDD-2103, which has demonstrated promising efficacy in treating chronic colitis. MethodsThe effect of CDD-2103 on epithelial barrier function was examined using in vitro and ex vivo models of tissue injury, as well as a chronic colitis C57BL/6 mouse model. Transcriptomic analysis was employed to profile gene expression changes in colonic tissues following treatment with CDD-2103. ResultsOur in vivo experiments demonstrated that CDD-2103 dose-dependently reduced disease severity in mice with chronic colitis. The efficacy of CDD-2103 was mediated by a reduction in goblet cell loss and the enhancement of tight junction protein integrity. Mechanistically, CDD-2103 suppressed epithelial cell apoptosis and tight junction protein breakdown by activating the soluble guanynyl cyclase (sGC)-mediated cyclic guanosine monophosphate (cGMP)/PKG signaling cascade. Molecular docking analysis revealed strong sGC ligand recognition by the CDD-2103-derived molecules, warranting further investigation. ConclusionOur study revealed a novel formulation CDD-2103 that restores intestinal barrier function through the activation of sGC-regulated cGMP/PKG signaling. Furthermore, our findings suggest that targeting sGC can be an effective approach for promoting mucosal healing in the management of UC.

HSP90β shapes the fate of Th17 cells with the help of glycolysis-controlled methylation modification.

Ulcerative colitis (UC) is a refractory inflammatory disease associated with immune dysregulation. Elevated levels of heat shock protein (HSP) 90 in the β but not α subtype were positively associated with disease status in UC patients. This study validated the possibility that pharmacological inhibition or reduction of HSP90β would alleviate colitis, induced by dextran sulfate sodium, in mice and elucidated its mechanisms. Histopathological and biochemical analysis assessed disease severity, and bioinformatics and correlation analysis explained the association between the many immune cells and HSP90β. Flow cytometry was used to analyse the homeostasis and transdifferentiation of Th17 and Treg cells. In vitro inhibition and adoptive transfer assays were used to investigate functions of the phenotypically transformed Th17 cells. Metabolomic analysis, DNA methylation detection and chromatin immunoprecipitation were used to explore these mechanisms. The selective pharmacological inhibitor (HSP90βi) and shHSP90β significantly mitigated UC in mice and promoted transformation of Th17 to Treg cell phenotype, via Foxp3 transcription. The phenotypically-transformed Th17 cells by HSP90βi or shHSP90β were able to inhibit lymphocyte proliferation and colitis in mice. HSP90βi and shHSP90β selectively weakened glycolysis by stopping the direct association of HSP90β and GLUT1, the key glucose transporter, to accelerate ubiquitination degradation of GLUT1, and enhance the methylation of Foxp3 CNS2 region. Then, the mediator path was identified as the "lactate-STAT5-TET2" cascade. HSP90β shapes the fate of Th17 cells via glycolysis-controlled methylation modification to affect UC progression, which provides a new therapeutic target for UC.

Arginase 2 attenuates ulcerative colitis by antioxidant effects of spermidine.

Spermidine suppress oxidative stress and is involved in various disease pathogenesis including ulcerative colitis (UC). Arginase 2 (ARG2) plays a central role in the synthesis of spermidine. This study aimed to clarify the effect of endogenously produced spermidine on colitis. The physiological role of ARG2 and spermidine was investigated using Arg2-deficient mice with reduced spermidine. Immunohistochemical staining of the rectum was used to analyze ARG2 expression and spermidine levels in healthy controls and UC patients. In mice with dextran sulfate sodium-induced colitis, ARG2 and spermidine levels were increased in the rectal epithelium. Spermidine protects colonic epithelial cells from oxidative stress and Arg2 knockdown cells reduced antioxidant activity. Organoids cultured from the small intestine and colon of Arg2-deficient mice both were more susceptible to oxidative stress. Colitis was exacerbated in Arg2-deficient mice compared to wild-type mice. Supplementation with spermidine result in comparable severity of colitis in both wild-type and Arg2-deficient mice. In the active phase of UC, rectal ARG2 expression and spermidine accumulation were increased compared to remission. ARG2 and spermidine levels were similar in healthy controls and UC remission patients. ARG2 produces spermidine endogenously in the intestinal epithelium and has a palliative effect on ulcerative colitis. ARG2 and spermidine are potential novel therapeutic targets for UC.

Exploring the Relevance of Disulfidptosis to the Pathophysiology of Ulcerative Colitis by Bioinformatics Analysis.

Ulcerative colitis (UC) is a nonspecific inflammatory disease confined to the intestinal mucosa and submucosa, and its prevalence significantly increases each year. Disulfidptosis is a recently discovered new form of cell death that has been suggested to be involved in multiple diseases. The aim of this study was to explore the relevance of disulfidptosis in UC. First, the UC datasets were downloaded from the Gene Expression Omnibus (GEO) database, and UC samples were typed based on upregulated disulfidptosis-related genes (DRGs). Then, weighted gene co-expression network analysis (WGCNA) was performed on the datasets and molecular subtypes of UC, respectively, to obtain candidate signature genes. After validation of the validation set and qRT-PCR, we constructed a nomogram model by signature genes to predict the risk of UC. Finally, single-cell sequencing analysis was used to study the heterogeneity of UC and to demonstrate the expression of DRGs and signature genes at the single-cell level. A total of 7 DRGs were significantly upregulated in the expression profiles of UC, and 180 UC samples were divided into two subtypes based on these DRGs. Five candidate signature genes were obtained by intersecting two key gene modules selected by WGCNA. After evaluation, four signature genes with diagnostic relevance (COL4A1, PRRX1, NNMT, and PECAM1) were eventually identified. The nomogram model showed excellent prediction ability. Finally, in the single-cell analysis, there were eight cell types (including B cells, T cells, monocyte, smooth muscle cells, epithelial cells, neutrophil, endothelial cells and NK cells) were identified. The signature genes were significantly expressed mainly in endothelial cells and smooth muscle cells. In this study, subtypes related to disulfidptosis were identified, and single-cell analysis was performed to understand the pathogenesis of UC from a new perspective. Four signature genes were screened and a prediction model with high accuracy was established. This provides novel insights for early diagnosis and therapeutic targets in UC.

Recent steroid use and the relapse risk in ulcerative colitis patients with endoscopic healing.

Endoscopic healing (EH) is a therapeutic target in ulcerative colitis (UC). However, even patients who have achieved EH relapse frequently. To investigate the association between recent steroid use and relapse risk in UC patients with EH. This multi-centre cohort study included 1212 UC patients with confirmed EH (Mayo endoscopic subscore ≤1). We excluded patients with current systemic steroid use or history of advanced therapy. We divided patients into a recent steroid group (last systemic steroid use within 1 year; n = 59) and a non-recent or steroid-naïve group (n = 1153). We followed the patients for 2 years to evaluate relapse, defined as induction of systemic steroids or advanced therapy. We used logistic regression to estimate the odds ratio (OR) of relapse. Relapse occurred in 28.8% of the recent steroid group and 5.6% of the non-recent/steroid-naïve group (multi-variable-adjusted OR 5.53 [95% CI 2.85-10.7]). The risk of relapse decreased with time since the last steroid use: 28.8% for less than 1 year after steroid therapy, 22.9% for 1 year, 16.0% for 2 years and 7.9% beyond 3 years, approaching 4.0% in steroid-naïve patients. (ptrend <0.001). Even for patients with UC who achieved EH, the risk of relapse remains high following recent steroid therapy. Physicians need to consider the duration since last steroid use to stratify the relapse risk in UC patients with EH.

Determining the optimal treatment target in patients with ulcerative colitis: rationale, design, protocol and interim analysis for the randomised controlled VERDICT trial

IntroductionSymptoms, endoscopy and histology have been proposed as therapeutic targets in ulcerative colitis (UC). Observational studies suggest that the achievement of histologic remission may be associated with a lower risk...

P489 Systematic review and meta-analysis of the accuracy of computer-aided diagnosis in identifying endoscopic remission in Ulcerative Colitis

Abstract Background Endoscopic remission (ER), the absence of active inflammation during endoscopy, is a key therapeutic target in Ulcerative Colitis (UC). ER is assessed during colonoscopy using standardised scoring systems. However, there remains significant inter-operator variability in assessing ER, for which the application of computer-aided diagnosis (CADx) could be a potential solution. A previous systematic review and meta-analysis on this topic was limited to literature up to June 2022 and did not assess the methodological quality of studies or heterogeneity amongst results. We aimed to update this review. Methods Searches were performed on six electronic databases and relevant reference lists up to May 2023. Data was extracted and screened independently by two reviewers. Methodological assessment was performed using the QUADAS-2 tool. An ‘image selection’ domain was added to the tool given the importance of endoscopic image quality in training and testing data on CADx’s accuracy. Meta-analysis was performed using a bivariate model. Heterogeneity was assessed through visual inspection of forest plots and receiver-operating characteristic curves, subgroup analyses and meta-regression. The overall quality of evidence was assessed using GRADE methodology. Results 17 studies (16 full-text articles and one abstract) were identified. 15 studies adopted a cross-sectional design. All studies used expert endoscopists scoring of ER as the reference standard. The Mayo Endoscopic Score was the most commonly used scoring system (13/17). CADx assessed ER in real-time in one study, but was applied to images and videos obtained from previous endoscopic procedures in all other studies. Inception-v3 was the most common CADx system used (6/17). ‘Patient selection’ was the domain of greatest concern due to a considerable number of studies using images from the same public database and under-reporting participant characteristics. All studies had a low risk of bias (ROB) in the ‘image selection’ domain. One study was deemed overall high ROB, and two were deemed overall unclear ROB. Sensitivity analysis was performed by removing these studies and the abstract, and pooled estimates were obtained from the remaining 13 studies. CADx had a pooled sensitivity of 90.3% and specificity of 94.6% for diagnosing ER. The overall quality of evidence was moderate due to the failure of a significant proportion of studies to report sufficient participant characteristics. Conclusion There is moderate quality evidence that CADx has high sensitivity and specificity for diagnosing ER in pre-clinical studies. Further evaluation is required in randomised controlled trials to evaluate its efficacy in real-time and human-computer interactions.

P403 A new criterion, combining bowel wall thickness and submucosal index (SMI), is useful for estimating endoscopic improvement in Ulcerative Colitis

Abstract Background Endoscopic improvement (EI), Mayo endoscopic subscore of 0 or 1, is considered a therapeutic target in ulcerative colitis (UC) treatment. The potential to estimate EI non-invasively is an advantage of intestinal ultrasound (IUS). In a former study, we developed a new ultrasound parameter, the submucosal index (SMI), calculated as the ratio of the thickness of the submucosa to the thickness of the bowel wall (BWT), and reported that combining BWT and SMI could be a practical criterion for estimating EI without the assessment of bowel wall vascularity using color Doppler evaluation. In the present study, we validated the EI estimation ability of our B-mode-based UC criterion, Kyorin Ultrasound Criterion for UC (KUC-UC; BWT&amp;lt;3.8mm and SMI&amp;lt;50%), using an external cohort. Methods Patients who underwent IUS and CS at Kyorin University Hospital were included. The inclusion criteria were (1) both IUS and endoscopy (sigmoidoscopy or CS) for UC were performed between July 2021 and June 2022, (2) the interval between IUS and endoscopy was within 15 days, and (3) no change or addition of therapeutic agents between the two examinations. IUS findings including BWT, SMI, and modified Limberg score were evaluated. In the modified Limberg score, the threshold of normal BWT was less than 3 mm, while the original Limberg score employed less than 4 mm. Results The KUC-UC criterion defined as BWT &amp;lt; 3.8 mm and SMI &amp;lt; 50.0% is practical because it uses only B-mode findings and does not require complex calculations. We tested the ability of this criterion to estimate EI in UC. A total of 122 colon segments were evaluated by transabdominal IUS and CS. The criteria showed a sensitivity of 67.3%, specificity of 97.1%, PPV of 94.6%, and NPV of 80.0%. In the previous development cohort, the PPV and NPV of KUC-UC were 95.5% and 82.7%, respectively. Based on the above, this validation cohort is considered equivalent to the development cohort. BWT &amp;lt; 3 mm and MUC have been reported as useful criteria for EI estimation. In the present cohort, BWT &amp;lt;3mm showed a sensitivity of 67.3%, specificity of 91.4%, PPV of 85.4%, and NPV of 79.0%, and MUC demonstrated a sensitivity of 75.0%, specificity of 88.6%, PPV of 83.0%, and NPV of 82.0%. These results indicate that KUC-UC has a considerable potential to estimate EI as BWT &amp;lt; 3 mm or MUC. Conclusion External validation showed that KUC-UC, using only B-mode findings without complicated calculations, is feasible, accurate sonographic criteria to estimate the EI of UC. The KUC-UC criterion could be one of the options for estimating EI in UC.

A combination of bowel wall thickness and submucosa index is useful for estimating endoscopic improvement in ulcerative colitis: external validation of the Kyorin Ultrasound Criterion.

Endoscopic improvement (EI; a Mayo endoscopic subscore of 0 or 1) is considered a therapeutic target in ulcerative colitis (UC) treatment. The potential to estimate EI non-invasively is an advantage of intestinal ultrasound (IUS). In a previous study, we developed a new sonographic parameter, the submucosa index (SMI), calculated as the ratio of the submucosal thickness to bowel wall thickness (BWT), and reported that combining BWT and SMI results in a practical and promising criterion for estimating EI without color Doppler assessment. This study aimed to validate the EI estimation ability of our B mode-based criterion, the 'Kyorin Ultrasound Criterion for UC' (KUC-UC; BWT < 3.8mm and SMI < 50%), using an external cohort. Patients with UC who underwent IUS and colonoscopy within 15days without a treatment change between examinations were included. IUS findings, including BWT, SMI, and modified Limberg score for vascularity of the colon, were assessed. Forty-four test pairs of IUS and colonoscopy examinations in a total of 122 colonic segments were analyzed. The KUC-UC showed positive predictive value (PPV) of 94.6% and negative predictive value (NPV) of 80.0% for EI. In comparison, PPV and NPV were 85.4% and 79.0%, respectively, for the common criterion BWT of < 3mm, and 83.0% and 82.7% for the validated Milan Ultrasound Criteria (a score of ≤ 6.2). External validation showed that the KUC-UC using only B mode findings without complicated calculations is a feasible and accurate sonographic criterion for estimating the EI of UC.

N-terminal ectodomain of BTNL2 inhibits T cell activation via a non-canonical interaction with its putative receptor that results in a delayed progression of DSS-induced ulcerative colitis

Butyrophilin-like 2 (BTNL2) is a T cell inhibitory molecule that interacts with unknown binding partners to modulate the immune response in a number of inflammatory and autoimmune diseases. In this study, we found that the inhibitory effects of BTNL2 on T cell activation and effector functions can be executed by its N-terminal IgV domain (BTNL2 IgV1) alone. Structure-guided mutation of key residues on BTNL2 IgV1 based on known receptor-ligand interfaces involving immunoglobulin superfamily members revealed that BTNL2 uses a non-canonical binding interface with its putative receptor. A high avidity BTNL2 IgV1 probe revealed that in an inducible model of ulcerative colitis, severe colitis was accompanied by a selective enrichment of BTNL2-receptor expressing effector-memory CD4+ and CD8+ T cells in the Peyer’s patches. Intraperitoneal administration of BTNL2 IgV1 resulted in a significant delay in the progression of DSS-induced colitis and also showed reduced activation of the BTNL2-receptor-expressing T cells in the Peyer’s patches. Thus, this study demonstrates that the BTNL2-receptor-expressing T cells in the Peyer’s patches participate in the disease pathogenesis and can serve as a novel therapeutic target in ulcerative colitis, which can be modulated by BTNL2 IgV1.

Intestinal epithelial damage-derived mtDNA activates STING-IL12 axis in dendritic cells to promote colitis.

Rationale: The treatment of ulcerative colitis (UC) presents an ongoing clinical challenge. Emerging research has implicated that the cGAS-STING pathway promotes the progression of UC, but conflicting results have hindered the development of STING as a therapeutic target. In the current study, we aim to comprehensively elucidate the origins, downstream signaling and pathogenic roles of myeloid STING in colitis and colitis-associated carcinoma (CAC). Methods: Tmem173 fl/fl Lyz2-Cre ert2 mice were constructed for inducible myeloid-specific deletion of STING. RNA-sequencing, flow cytometry, and multiplex immunohistochemistry were employed to investigate immune responses in DSS-induced colitis or AOM/DSS-induced carcinogenesis. Colonic organoids, primary bone marrow derived macrophages and dendritic cells, and splenic T cells were used for in vitro studies. Results: We observed that myeloid STING knockout in adult mice inhibited macrophage maturation, reduced DC cell activation, and suppressed pro-inflammatory Th1 and Th17 cells, thereby protecting against both acute and chronic colitis and CAC. However, myeloid STING deletion in neonatal or tumor-present mice exhibited impaired immune tolerance and anti-tumor immunity. Furthermore, we found that TFAM-associated mtDNA released from damaged colonic organoids, rather than bacterial products, activates STING in dendritic cells in an extracellular vesicle-independent yet endocytosis-dependent manner. Both IRF3 and NF-κB are required for STING-mediated expression of IL-12 family cytokines, promoting Th1 and Th17 differentiation and contributing to excessive inflammation in colitis. Conclusions: Detection of the TFAM-mtDNA complex from damaged intestinal epithelium by myeloid STING exacerbates colitis through IL-12 cytokines, providing new evidence to support the development of STING as a therapeutic target for UC and CAC.

Identification of novel N7-methylguanine-related gene signatures associated with ulcerative colitis and the association with biological therapy.

Ulcerative colitis (UC) is an inflammatory disease characterized by recurrent episodes of chronic intestinal inflammation. It is closely associated with immune dysregulation in the intestines. However, the mechanisms underlying the role of immune-related N7-methylguanosine (m7G) internal modification in UC remain unclear. We conducted a screening of differentially expressed genes (DEGs) associated with m7G and performed immune infiltration analysis. We then investigated the correlation between m7G-related DEGs and immune cells or pathways. To further explore the functional implications, we conducted functional enrichment analysis to identify gene modules that strongly correlated with hub gene expression. In addition, we constructed a miRNA regulatory network for the hub genes in UC. Furthermore, we examined the association between hub genes and disease remission in UC patients undergoing biologic therapy. We obtained 13 m7G-related DEGs and conducted an in-depth analysis of immune infiltration. Among them, we identified five hub genes (NUDT7, NUDT12, POLR2H, QKI, and PRKCB) that showed diagnostic potential for UC. Through WGCNA and KEGG analysis, we found that gene modules strongly correlated with m7G hub gene expression were enriched in inflammation-related pathways. Furthermore, Kaplan-Meier survival analysis revealed a significant association between changes in hub gene expression levels and disease remission in UC patients undergoing biologic therapy. The findings of this study demonstrate that five m7G-related DEGs, including the m7G-modified recognition protein QKI, play a key role in the occurrence and progression of UC intestinal inflammation, which is closely related to intestinal immunity. These results provide valuable insights into the mechanisms of m7G modification in UC development and offer new perspectives for exploring novel therapeutic targets for UC.

CIRC_0085323 SILENCING INHIBITS TNF-Α-INDUCED NORMAL HUMAN COLONIC EPITHELIAL CELL INFLAMMATION AND APOPTOSIS THROUGH THE MIR-495-3P/TRAF3 AXIS.

Background: Previous data have suggested the involvement of circular RNA (circRNA) in ulcerative colitis (UC) development. However, the role and mechanism of circ_0085323 in UC occurrence have not been reported. Methods: Normal human colonic epithelial cells (NCM460) were treated with TNF-α to simulate UC-like cell inflammation and injury in vitro. The expression of circ_0085323, microRNA-495-3p (miR-495-3p), and TNF receptor-associated factor 3 (TRAF3) was detected by quantitative real-time polymerase chain reaction. Protein expression was checked by western blotting analysis. Cell viability, cell proliferation, and cell apoptosis were investigated by cell counting kit-8 assay, 5-ethynyl-29-deoxyuridine assay, and flow cytometry analysis, respectively. IL-1β, IL-6, and IL-8 production were analyzed by enzyme-linked immunosorbent assays. Lactate dehydrogenase activity was assessed by a lactate dehydrogenase activity detection assay. The interactions among circ_0085323, miR-495-3p, and TRAF3 were identified by dual-luciferase reporter assay and RNA immunoprecipitation assay. Results: Circ_0085323 was overexpressed in the colonic mucosal tissues of UC patients and TNF-α-stimulated NCM460 cells. Circ_0085323 knockdown relieved TNF-α-induced inhibitory effect on the proliferation of NCM460 cells and promoting effects on cell apoptosis and inflammation. Circ_0085323 acted as a miR-495-3p sponge, and the effects of circ_0085323 silencing on TNF-α-induced NCM460 cell injury were attenuated by decreasing miR-495-3p expression. TRAF3 was targeted by miR-495-3p, and circ_0085323 combined with miR-495-3p to regulate TRAF3. TRAF3 depletion not only alleviated TNF-α-induced NCM460 cell damage but also partially revoked the effect of circ_0085323 silencing combined with miR-495-3p depletion on TNF-α-induced NCM460 cell injury. Conclusions: Circ_0085323 knockdown ameliorated TNF-α-induced NCM460 cell injury by regulating the miR-495-3p/TRAF3 axis, which suggested that circ_0085323 might be a therapeutic target for UC.

Excessive Mitochondrial Fission Suppresses Mucosal Repair by Impairing Butyrate Metabolism in Colonocytes.

Mucosal healing is one of the principal therapeutic targets for ulcerative colitis (UC). Mitochondria are dynamic organelles that undergo constant fusion and fission; however, the process that is most conducive to mucosal healing remains unclear. This study investigated the role of mitochondrial fission in mucosal healing in UC patients. Quantitative polymerase chain reaction, Western blotting, and immunostaining were used to detect mitochondrial fission in UC patients and a dextran sulfate sodium-induced colitis model. Colonic organoids were used to investigate the role of mitochondrial fission in butyrate metabolism. Enzyme activity assays were performed to identify the key proteins involved in this mechanism. It was found that inhibition of mitochondrial fission promoted mucosal healing in mice and that there was an increase in mitochondrial fission in colonic epithelial cells of UC patients. Excessive fission inhibits stem cell proliferation by impairing butyrate metabolism in colonic organoids. The mitochondrial fission antagonist P110 failed to promote mucosal healing in antibiotic-treated mice, and the addition of exogenous butyrate reversed this effect. Increased butyrate exposure in the colonic stem cell niche has also been observed in UC patients. Mechanistically, enzyme activity assays on colonic organoids revealed that excessive fission inhibits mitochondrial acetoacetyl-CoA thiolase activity via reactive oxygen species. Collectively, these data indicate that excessive mitochondrial fission suppresses mucosal repair by inhibiting butyrate metabolism and provides a potential target for mucosal healing in patients with ulcerative colitis.

Ferroptosis in the colon epithelial cells as a therapeutic target for ulcerative colitis.

Ferroptosis, a type of programmed cell death triggered by oxidative stress, was suspected to play a role in ulcerative colitis. Indigo naturalis is highly effective against ulcerative colitis, but its mechanism is unclear. This study found that indigo naturalis treatment suppressed ferroptosis. We analyzed 770 mRNA expressions of patients with ulcerative colitis. Suppression of ferroptosis by indigo naturalis treatment was shown using a cell death assay. Malondialdehyde levels and reactive oxygen species were analyzed in CaCo-2 cells treated with indigo naturalis. Glutathione metabolism was shown by metabolomic analysis. Extraction of the ingredients indigo naturalis from the rectal mucosa was performed using liquid chromatograph-mass spectrometry. Gene expression profiling showed that indigo naturalis treatment increased antioxidant genes in the mucosa of patients with ulcerative colitis. In vitro analysis showed that nuclear factor erythroid-2-related factor 2-related antioxidant gene expression was upregulated by indigo naturalis. Indigo naturalis treatment rendered cells resistant to ferroptosis. Metabolomic analysis suggested that an increase in reduced glutathione by indigo naturalis. The protein expression of CYP1A1 and GPX4 was increased in the rectum by treatment with indigo naturalis. The main ingredients of indigo naturalis, indirubin and indigo inhibited ferroptosis. Indirubin was detected in the rectal mucosa of patients with ulcerative colitis who were treated with indigo naturalis. Suppression of ferroptosis by indigo naturalis in the intestinal epithelium could be therapeutic target for ulcerative colitis. The main active ingredient of indigo naturalis may be indirubin.