Pathogenesis Of Inflammatory Bowel Disease Research Articles

Resveratrol alleviates inflammatory bowel disease by inhibiting JAK2/STAT3 pathway activity via the reduction of O-GlcNAcylation of STAT3 in intestinal epithelial cells

The role of O-linked N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation) in the pathogenesis of inflammatory bowel disease (IBD) has been increasingly highlighted in recent studies. It's been reported that signal transducer and activator of transcription 3 (STAT3) O-GlcNAcylation can affect the activity of the Janus kinase2 (JAK2)/STAT3 pathway.Our recent study showed that resveratrol repairsIBDin mice.On this basis,the present study aimed to explore whether the mechanism of IBD repair by resveratrol is associated with STAT3 O-GlcNAcylation. Pretreatment of colitis mice and intestinal epithelial cells with an O-GlcNAcylation promoter (Thiamet G, or Glucosamine) and an O-GlcNAcylation inhibitor (OSMI-1) showed that increased O-GlcNAcylation promoted colitis in mice.The pro-inflammatory cytokines interleukin (IL) -6, IL-1β, and tumor necrosis factor-α (TNF-α) were increased, while the anti-inflammatory cytokine IL-10 was decreased. Moreover, the downstream target proteins of JAK2/STAT3, cyclooxygenase-2 and nitric oxide synthase 2 were up-regulated, Resveratrol treatment mitigated the inflammation by decreasing JAK2/STAT3 activity, as well as STAT3 O-GlcNAcylation. Finally, the correlation between STAT3 glycosylation and phosphorylation in intestinal epithelial cells under the effect of resveratrol was investigated by Immunofluorescence co-localization and immunoprecipitation.The results showed that resveratrol inhibited STAT3 O-GlcNAcylation, thereby inhibiting its phosphorylation, reducing JAK2/STAT3 pathway activity, and alleviating IBD.

ETS translocation variant 5 (ETV5) promotes CD4+ T cell–mediated intestinal inflammation and fibrosis in inflammatory bowel diseases

ETS translocation variant 5 (ETV5) has been implicated in the pathogenesis of inflammatory bowel disease (IBD). However, the exact roles of ETV5 in regulating CD4+ T cell-mediated intestinal inflammation and fibrosis formation remain unclear. Here, we reveal that ETV5 overexpression induced IL-9 and its transcription factor IRF4 expression in naïve IBD CD4+ T cells under Th9-polarizing conditions. Silencing of IRF4 inhibited ETV5-induced IL-9 expression. CD4+ T cell-specific ETV5 deletion (CKO) ameliorated intestinal inflammation and fibrosis in TNBS-induced experimental colitis and CD4+ T cell-transferred Rag1-/- colitis mice, characterized by less CD4+ T cell infiltration, lower fibroblast activation and collagen deposition in the colonic tissues. Furthermore, IL-9 treatment aggressive TNBS-induced intestinal fibrosis in CKO and wild type (WT) control mice. In vitro, human intestinal fibroblasts cocultured with ETV5 overexpressed-Th9 cells expressed higher levels of collagen I and III, whereas an inclusion of anti-IL-9 antibody could reverse this effect. RNA sequencing analysis demonstrated that IL-9 upregulated TAF1 expression in human intestinal fibroblasts. Clinic data showed that number of α-SMA+TAF1+ fibroblasts are higher in inflamed mucosa of IBD patients. Importantly, TAF1 siRNA treatment suppressed IL-9-mediated profibrotic effect in vitro. These findings reveal that CD4+ T cell-derived ETV5 promotes intestinal inflammation and fibrosis through upregulating IL-9-mediated intestinal inflammatory and fibrotic response in IBD. Thus, the ETV5/IL-9 signal pathway in T cells might represent a novel therapeutic target for intestinal inflammation and fibrosis in IBD.

Integrated single-cell and bulk RNA sequencing reveals CREM is involved in the pathogenesis of ulcerative colitis

BackgroundUlcerative colitis (UC) is an inflammatory bowel disease characterized by persistent colonic inflammation. Here, we performed a systematic analysis to gain better insights into UC pathogenesis. MethodsWe analyzed two UC-related datasets extracted from the gene expression omnibus database using several bioinformatics tools. The primary cell types and key subgroups of primary cells associated with UC and differentially expressed genes (DEGs) between UC and control samples were identified. The molecular regulation of the key genes was also predicted. The gene ontology and Kyoto encyclopedia of genes and genomes enrichment analyses of marker genes of key cell subgroups and model genes were performed. The expression of key enriched genes was validated in 10 clinical samples using real-time quantitative polymerase chain reaction (RT-qPCR). ResultsMonocytes were identified as the major cell type. Ten differentially expressed marker genes were obtained by intersecting the 3121 DEGs, 38 marker genes in major cell types, and 104 marker genes in key cell subgroups. Four essential genes, associated with immune response, were obtained using support vector machine recursive feature elimination and least absolute shrinkage and selection operator analyses. The four essential genes were highly expressed in Cluster 0 during differentiation. Validation of the four key genes in colonic mucosal biopsy specimens from 10 normal and 10 UC patients revealed that CREM was highly expressed in both the lesion-free sites and lesion sites colonic mucosa of UC patients compared with normal adults. ConclusionsWe identified CREM involved in UC pathogenesis, which is expected to provide a new therapeutic target for UC.

Discerning Endoscopic Severity of Inflammatory Bowel Disease by Scoping the Peripheral Blood Transcriptome

Background and AimsUlcerative colitis (UC) and Crohn’s disease (CD) are chronic inflammatory bowel diseases (IBD) with an incompletely understood etiology and pathogenesis. Identification of suitable drug targets and assessment of disease severity are crucial for optimal management. MethodsUsing RNA-sequencing, we investigated differential gene expression in peripheral blood samples from IBD-patients and non-inflamed controls, analysed pathway enrichment, and identified genes whose expression correlated with endoscopic disease severity. ResultsNeutrophil degranulation emerged as the most significant pathway across all IBD sample types. Signalling by interleukins was prominent in patients with active intestinal inflammation, but also enriched in CD and UC patients without intestinal inflammation. Nevertheless, genes correlated to endoscopic disease severity implicated the primary cilium in CD patients, and translation and focal adhesion in UC patients. Moreover, several of these genes were located in genome-wide associated loci linked to IBD, cholesterol levels, blood cell counts, and levels of markers assessing liver and kidney function. These genes also suggested connections to intestinal epithelial barrier dysfunction, contemporary IBD drug treatment, and new actionable drug targets. A large number of genes associated with endoscopic disease severity corresponded to non-coding RNAs. ConclusionsThis study revealed biological pathways associated with IBD disease state and endoscopic disease severity, thus providing insights into the underlying mechanisms of IBD pathogenesis as well as identifying potential biomarkers and therapies. Peripheral blood might constitute a suitable non-invasive diagnostic sample type, in which gene expression profiles might serve as indicators of ongoing mucosal inflammation, and thus guide personalized treatment decisions.

Hyper Mucinous Proliferations in the Mucosa of Patients with Inflammatory Bowel Disease: Histological Lesions with a Real Potential for Neoplastic Evolution?

Mucin disfunction is a critical event in the pathogenesis of inflammatory bowel disease (IBD). Although hyper mucinous conditions have a still debated implication in the clinical evolution of this disorder, hyper mucinous villous proliferations were found to have a preneoplastic biologic potential. We studied morphologic and immunophenotypic characteristics of these lesions in ileocolonic resections for IBD to add evidence about the evolutive potential of these lesions in samples with well oriented wall structures. Morphologic characteristics of bowel samples from 20 patients resected for IBD and with raised lesions at gross examination were studied and sections from cases with hyper mucinous lesions were stained with the following antibodies: Ki 67, p21, and p27, which were employed to evaluate the characteristics of the proliferative and differentiative activity of the epithelial structures; mismatch repair proteins and p53 have been studied as proteins implicated in carcinogenesis in IBD-affected mucosa; mucins subtypes in hyper mucinous structures were evaluated with MUC-2 and MUC-6. The results in 11 cases of saplings were that they harbored hyper mucinous proliferations. The occurrence of hyper mucinous structures was not related to dysplastic lesions, pseudo pyloric metaplasia, subtype of disease, or activity. In only one of our cases, mild cytologic atypia in the proliferative compartment was detected. Proliferation markers (Ki 67, p53) were expressed in the proliferative compartments of mucosal crypts and antiproliferative proteins p21 and p27 were expressed in differentiated epithelium. MMR proteins expression was limited to the proliferative compartment of the hyper mucinous projections. Mucin subtypes distribution was regular in the epithelium of hyper mucinous proliferations. The present monocentric retrospective study was conducted on surgical samplings with well oriented crypts. Collected data show that hyper mucinous features are frequent occurrences in raised lesions in IBD patients. In hyper mucinous proliferations of the selected cases, the status of the proliferative cycle, the expression of the proteins most frequently involved in carcinogenetic pathways of mucosa affected by IBD, and the mucins subtypes expression have no evident anomalies. Findings are not consistent with the increased risk of neoplastic evolution observed in other studies; rather, they suggest a hyperplastic nature. However, the capacity of hyper mucinous raised lesions for neoplastic evolution should be ruled out with more extensive prospective studies to identify functional defects that could explain the hypothesized neoplastic potential.

Intestinal stroma guides monocyte differentiation to macrophages through GM-CSF

Stromal cells support epithelial cell and immune cell homeostasis and play an important role in inflammatory bowel disease (IBD) pathogenesis. Here, we quantify the stromal response to inflammation in pediatric IBD and reveal subset-specific inflammatory responses across colon segments and intestinal layers. Using data from a murine dynamic gut injury model and human ex vivo transcriptomic, protein and spatial analyses, we report that PDGFRA+CD142−/low fibroblasts and monocytes/macrophages co-localize in the intestine. In primary human fibroblast-monocyte co-cultures, intestinal PDGFRA+CD142−/low fibroblasts foster monocyte transition to CCR2+CD206+ macrophages through granulocyte-macrophage colony-stimulating factor (GM-CSF). Monocyte-derived CCR2+CD206+ cells from co-cultures have a phenotype similar to intestinal CCR2+CD206+ macrophages from newly diagnosed pediatric IBD patients, with high levels of PD-L1 and low levels of GM-CSF receptor. The study describes subset-specific changes in stromal responses to inflammation and suggests that the intestinal stroma guides intestinal macrophage differentiation.

Moxibustion alleviates intestinal inflammation in ulcerative colitis rats by modulating long non-coding RNA LOC108352929 and inhibiting Phf11 expression

Long noncoding RNA (lncRNAs) are involved in the pathogenesis of ulcerative colitis (UC). Moxibustion, a traditional Chinese medicine, can improve symptoms in patients with UC and reduce intestinal inflammation in rats with UC. However, it remains unclear whether the ameliorative effect of moxibustion on intestinal mucosal inflammation in UC is related to lncRNAs. Thirty-two rats were randomly assigned to four groups: normal control, UC, moxibustion (MOX), and sulfasalazine (SASP). The UC rat model was induced by administering 4% dextran sulfate sodium (DSS) in drinking water. Rats in the moxibustion group underwent bilateral Tianshu (ST25) moxibustion using the herbs-partition moxibustion method. Rats in the sulfasalazine group received SASP solution via gavage twice daily for seven consecutive days. Our results revealed that, compared with the UC group [2.00 (1.00, 2.50)], the DAI score [0.25 (0.00, 0.50)] was significantly lower in the MOX group (P < 0.05). Compared with the UC group [13.00 (11.25, 14.00)], the histopathological score [5.50 (4.00, 7.75)] was significantly lower in the MOX group (P < 0.05). In addition, the CMDI and macroscopic scores were decreased in the MOX group (P < 0.05). Moxibustion significantly decreased the protein expression of inflammatory factors TNF-α, IFN-γ, and IL-1β in the colonic tissues of UC rats (P <0.05), thereby suppressing the inflammatory response. Moreover, moxibustion exerted a regulatory influence on colon lncRNA and mRNA expression profiles, upregulating LOC108352929 and downregulating Phf11 in rats with UC (P <0.05). Moxibustion also led to a reduction in the expression and colocalization of Phf11 and NF-κB in the colons of UC rats. Moreover, knockdown of LOC108352929 in rat enteric glial cells demonstrated a significant upregulation of TNF-α mRNA expression (P <0.05). In summary, these data illustrate that moxibustion effectively ameliorates DSS-induced colonic injury and inflammation while exerting regulatory control over the lncRNA-mRNA co-expression network in UC rats. Collectively, the in vivo and in vitro studies suggested that LOC108352929-Phf11 may serve as a potential biological marker for moxibustion in the treatment of UC.

The gut ileal mucosal virome is disturbed in patients with Crohn’s disease and exacerbates intestinal inflammation in mice

Gut bacteriome dysbiosis is known to be implicated in the pathogenesis of inflammatory bowel disease (IBD). Crohn’s disease (CD) is an IBD subtype with extensive mucosal inflammation, yet the mucosal virome, an empirical modulator of the bacteriome and mucosal immunity, remains largely unclear regarding its composition and role. Here, we exploited trans-cohort CD patients and healthy individuals to compositionally and functionally investigate the small bowel (terminal ileum) virome and bacteriome. The CD ileal virome was characterised by an under-representation of both lytic and temperate bacteriophages (especially those targeting bacterial pathogens), particularly in patients with flare-up. Meanwhile, the virome-bacteriome ecology in CD ileal mucosa was featured by a lack of Bifidobacterium- and Lachnospiraceae-led mutualistic interactions between bacteria and bacteriophages; surprisingly it was more pronounced in CD remission than flare-up, underlining the refractory and recurrent nature of mucosal inflammation in CD. Lastly, we substantiated that ileal virions from CD patients causally exacerbated intestinal inflammation in IBD mouse models, by reshaping a gut virome-bacteriome ecology preceding intestinal inflammation (microbial trigger) and augmenting microbial sensing/defence pathways in the intestine cells (host response). Altogether, our results highlight the significance of mucosal virome in CD pathogenesis and importance of mucosal virome restoration in CD therapeutics.

Research progress of Ustekinumab in the treatment of inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic, recurrent gastrointestinal disorder with elusive etiology. Interleukin-12 (IL-12) and IL-23 have emerged as key proinflammatory mediators/cytokines in IBD pathogenesis. Ustekinumab (UST), targeting IL-12 and IL-23, has demonstrated promising efficacy and safety in the treatment of IBD. Recently, UST has become increasingly favored as a potential first-line treatment option. This review delineates UST's mechanism of action, its clinical applications in IBD, including the response rates, strategies for dose optimization for case of partial or lost response, and potential adverse events. This review aims to offer a comprehensive understanding of UST's role as a therapeutic option in IBD management.

Effect of tofacitinib on the phenotype and activity of Caco‑2 cells in a model of inflammatory bowel disease.

Reports have indicated that autoimmune bowel disorders affect an increasing number of people on every continent; therefore, it is important to better understand inflammatory bowel disease (IBD) and to explore new treatment options for patients suffering from it. Research has indicated the important role of enterocytes in IBD. Understanding the role of the intestinal epithelium in the pathogenesis of IBD may contribute to a better understanding of the inflammatory processes and aid in the identification of potential therapeutic treatments. The present study aimed to evaluate the effects of tofacitinib on Caco-2 cells cultured in an inflammatory environment induced using cytokines naturally found in patients with ulcerative colitis. Tofacitinib is an orally administered inhibitor of Janus kinases (JAKs) which, by modifying the JAK/STAT signaling pathway, reduces the effect of inflammatory cytokines in the gut. Caco-2 cells were used to model the intestinal epithelium and the culture conditions included the proinflammatory cytokine TNFα and tofacitinib. At the end of the culture period, enzymes involved in oxidative stress (superoxide dismutase 1, catalase, nicotinamide adenine dinucleotide phosphate), a marker of apoptosis (Bcl-2) and a key player in intracellular inflammatory signaling (nuclear factor κB) were assessed by quantitative PCR and western blotting. The in vitro phenotype of Caco-2 cells exposed to an inflammatory environment was observed to be similar to that observed in ulcerative colitis. Notably, tofacitinib was able to improve TNFα-induced changes in an in vitro model of ulcerative colitis, and a reduction in the activity of enzymes associated with oxidative stress was observed. In addition, tofacitinib-induced upregulation of Bcl-2 and claudin-1 may contribute to the beneficial effects of tofacitinib on the intestinal epithelium. Tofacitinib appears to have a protective effect on Caco-2 cells. Notably, in the present study, exposure to TNFα stimulated oxidative stress and apoptotic effects, and disrupted intercellular connectivity. The addition of tofacitinib decreased the activity of the examined parameters of oxidative and apoptotic stress, while increasing the activity of the parameter examined to evaluate the degree of intercellular connections. In conclusion, the inhibitory effects of tofacitinib on oxidative stress, as well as its anti-apoptotic and regenerative effects, provide important information regarding the positive effect of tofacitinib on Caco-2 cells, and therefore constitute potential information about the beneficial effect of the evaluated drug in UC.

The Role of Gut Microbiome in the Pathogenesis and the Treatment of Inflammatory Bowel Diseases.

Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease, is a chronic condition characterized by inflammation of the gastrointestinal tract. Its exact cause is unknown, but it's thought to result from a dysregulated immune response influenced by various factors, including changes in the intestinal microbiota, diet, lifestyle, and genetics. The gut microbiome, consisting of diverse microorganisms, plays a crucial role in maintaining physiological balance, with its disruption leading to inflammatory responses typical of IBD. Treatments primarily aim at symptom control, employing immunomodulators, corticosteroids, and newer approaches like probiotics, prebiotics, fecal transplants, and dietary modifications, all focusing on leveraging the microbiota's potential in disease management. These strategies aim to restore the delicate balance of the gut microbiome, typically altered in IBD, marked by a decrease in beneficial bacteria and an increase in harmful pathogens. This review underscores the importance of the gut microbiome in the pathogenesis and treatment of IBD, highlighting the shift towards personalized medicine and the necessity for further research in understanding the complex interactions between the gut microbiota, immune system, and genetics in IBD. It points to the potential of emerging treatments and the importance of a multifaceted approach in managing this complex and challenging disease.

Immune checkpoint inhibitor-related colitis in patients on immunotherapy for cancer.

Immune checkpoint inhibitors, a revolutionary class of cancer immunotherapy drugs, have transformed cancer treatment by bolstering antitumor immunity for various advanced-stage solid cancers. The US Food and Drug Administration has approved 7 immune checkpoint inhibitors that target 3 major immune checkpoint proteins: cytotoxic T-lymphocyte-associated protein 4, programmed cell death 1 protein, and programmed cell death 1 ligand 1. In addition to their remarkable efficacy, however, these inhibitors have been observed causing immune-related adverse events, particularly immune checkpoint inhibitor-related colitis, which often results in severe or life-threatening clinical issues. The diagnosis of immune checkpoint inhibitor-related colitis relies on incorporation of clinical evaluation as well as endoscopic and histopathologic examination, with exclusion of other potential etiologies. The common histopathologic manifestations of immune checkpoint inhibitor-related colitis are acute active colitis, chronic active colitis, microscopic colitis (collagenous or lymphocytic), and ischemic colitis, with patterns overlapping. Notably, enterocyte apoptosis is a unique feature of immune checkpoint inhibitor toxicity. The proposed mechanisms for the pathogenesis of immune checkpoint inhibitor-related colitis are primarily associated with autoimmune-type dysregulation and gut microbiome alteration. This review summarizes the clinical and pathologic characteristics of immune checkpoint inhibitor-related colitis and elucidates its underlying pathogenic mechanisms. Future successful management of this form of colitis relies on our comprehension of the intricate interplay between tumoral and systemic immune responses to immune checkpoint inhibitors and innovative approaches to modify these responses, along with specific immune cell populations, to preclude immune-related adverse events while achieving antitumor therapeutic outcomes.

The phospholipid flippase ATP8B1 is involved in the pathogenesis of Ulcerative Colitis via establishment of intestinal barrier function.

Patients with mutations in ATP8B1 develop Progressive Familial Intrahepatic Cholestasis type 1 (PFIC1), a severe liver disease that requires life-saving liver transplantation. PFIC1 patients also present with gastrointestinal problems, including intestinal inflammation and diarrhea, which are aggravated after liver transplantation. Here we investigate the intestinal function of ATP8B1 in relation to inflammatory bowel diseases. ATP8B1 expression was investigated in intestinal samples of patients with Crohn's Disease (CD) or Ulcerative Colitis (UC) as well as in murine models of intestinal inflammation. Colitis was induced in ATP8B1-deficient mice with Dextran Sodium Sulphate (DSS) and intestinal permeability was investigated. Epithelial barrier function was assessed in ATP8B1 knock-down Caco2-BBE cells. Co-immunoprecipitation experiments were performed in Caco2-BBE cells overexpressing ATP8B1-eGFP. Expression and localization of ATP8B1 and tight junction proteins were investigated in cells and in biopsies of UC and PFIC1 patients. ATP8B1 expression was decreased in UC and DSS-treated mice, and associated with a decreased Tight Junctional pathway transcriptional program. ATP8B1-deficient mice were extremely sensisitve to DSS-induced colitis, evidenced by increased intestinal barrier leakage. ATP8B1 knockdown cells showed delayed barrier establishment that associated with affected Claudin-4 (CLDN4) levels and localization.. CLDN4 immunohistochemistry showed a tight-junctional staining in control tissue, whereas in UC and intestinal PFIC1 samples, CLDN4 was not properly localized. ATP8B1 is important in the establishment of the intestinal barrier Downregulation of ATP8B1 levels in UC, and subsequent altered localization of tight junctional proteins, including CLDN4, might therefore be an important mechanism in UC pathophysiology.

A245 CROHN’S DISEASE-ASSOCIATED BACTERIAL PATHOBIONT EVOKED EPITHELIAL MITOCHONDRIAL DAMAGE DRIVES TYPE I INTERFERON EXPRESSION

Abstract Background The Crohn’s disease-associated adherent invasive E. coli (AIEC) (strain LF82) decreases mitochondrial membrane potential and fragments the epithelial mitochondrial network. Due to the evolutionary history of mitochondria as former bacteria, they present a variety of molecular patterns known to trigger innate immune responses. Specifically, mitochondrial DNA (mtDNA) released following mitochondrial damage causes upregulation of type I interferons, priming inflammatory signalling. Thus, we hypothesized that AIEC-induced mitochondrial dysfunction results in mtDNA release to activate innate immune signalling that could contribute to disease pathogenesis in the gut. Aims We aimed determine if an inflammatory response occurs downstream of mitochondrial damage evoked by E. coli-LF82 infection. Methods Control T84 epithelial cells, T84s infected E. coli-LF82 (108 cfu, MOI=100, 4h) and T84s infected with the commensal E. coli-HB101 (108 cfu for an MOI=100, 4h) were collected for protein and RNA extraction. RNA was used to measure IFNα and IFNβ expression following infection, while protein was used to measure upstream mediators including phosphorylation of TANK Binding Kinase-1 (TBK1) via Western blot. Results Epithelia infected with E. coli-LF82 but not E. coli-HB101 displayed dramatic fragmentation of their mitochondria network and increased levels of phosphorylated-TBK1 compared to control T84 cells (pampersand:003C0.01). Assessment of IFNα and IFNβ mRNA revealed significant up-regulation E. coli-LF82 infected T84 cells and human colon organoids. Conclusions Our findings identify a novel role for E. coli-LF82 in activating type I interferon response and for the first time show AIEC-induced activation of TBK1 and type I interferons, which may occur through mitochondrial damage, rather than through response to bacterial molecular patterns. As a result, our findings suggest that the AIEC colonization seen in Crohn’s disease may dysregulate inflammatory signalling through mitochondrial damage. Ultimately, we believe this dysregulation of inflammatory signalling may sensitize the host to further inflammatory signalling, contributing to the pathogenesis of inflammatory bowel disease. Funding Agencies CIHR

MiR-30c affects the pathogenesis of ulcerative colitis by regulating target gene VIP

MicroRNAs play a crucial role in regulating the epithelial barrier and immune response, which are implicated in the pathogenesis of ulcerative colitis (UC). This study aimed to investigate the role and molecular mechanism of miR-30c in the pathogenesis of UC using a dextran sulfate sodium salt (DSS)-induced colitis model, which is similar to ulcerative colitis. Wild-type (WT) and miR-30c knockout (KO) mice were assigned to either control or DSS-treated groups to evaluate the influence of aberrant miR-30c expression on UC pathogenesis. The disease activity index, inflammatory factors, and the extent of pathological and histological damage in colon tissues were analyzed. The effect of miR-30c on vasoactive intestinal peptide (VIP) gene expression was validated through luciferase reporter assay, qRT-PCR, Western blotting, and immunohistochemistry. The results showed that miR-30c KO mice with DSS-induced colitis model showed more severe phenotypes: significantly higher disease activity indices, significant body weight loss, reduced length of the colon of mice, increased number of aberrant crypt structures, reduced mucus secretion, and significant differences in inflammatory factors. These findings suggested that the absence of miR-30c might promote DSS-induced colitis, and the targe-regulatory effect of miR-30c on VIP might play an important role in the development of colitis.

An in vitro model to study immune activation, epithelial disruption and stromal remodelling in inflammatory bowel disease and fistulising Crohn's disease.

At present, preclinical models of inflammatory bowel disease (IBD) are insufficient, limiting translation between research and new therapeutics. This is especially true for fistulising Crohn's disease (CD), as the severe lack of relevant models hinders research progression. To address this, we present in vitro human IBD mucosal models that recapitulate multiple pathological hallmarks of IBD simultaneously in one model system - immune cell infiltration, stromal remodelling and epithelial disruption. Stimulation of models induces epithelial aberrations common in IBD tissue including altered morphology, microvilli abnormalities, claudin gene expression changes and increased permeability. Inflammatory biomarkers are also significantly increased including cytokines and chemokines integral to IBD pathogenesis. Evidence of extracellular matrix remodelling, including upregulated matrix-metalloproteinases and altered basement membrane components, suggests the models simulate pathological stromal remodelling events that closely resemble fistulising CD. Importantly, MMP-9 is the most abundant MMP and mimics the unique localisation observed in IBD tissue. The inflamed models were subsequently used to elucidate the involvement of TNF-α and IFN- γ in intestinal stromal remodelling, in which TNF-α but not IFN- γ induced MMP upregulation, specifically of MMP-3 and MMP-9. Collectively, our results demonstrate the potential of the IBD models for use in preclinical research in IBD, particularly for fistulising CD.

Challenges and opportunities in inflammatory bowel disease: from current therapeutic strategies to organoid-based models.

Inflammatory bowel disease (IBD) is an increasingly prevalent global health concern that has garnered substantial attention. However, the underlying mechanisms are still unclear and the current treatments have significant limitations. Intestinal organoids provide an in vitro model to explore the pathogenesis, test the therapeutic effects, and develop regenerative treatments as well as offer the potential to transform drug discovery of IBD. To advance our understanding of the whole story of IBD spanning from the pathogenesis to the current therapeutic strategies and latest advancements, a comprehensive search of major databases including PubMed, Scopus, and Web of Science was conducted to retrieve original articles and reviews related to IBD, organoids, pathogenesis and therapy. This review deciphers the etiopathogenesis and the current therapeutic approaches in the treatment of IBD. Notably, critical aspects of intestinal organoids in IBD, such as their potential applications, viability, cell renewal ability, and barrier functionality are highlighted. We also discuss the advances, limitations, and prospects of intestinal organoids for precision medicine. The latest strides made in research about intestinal organoids help elucidate intricate aspects of IBD pathogenesis, and pave the prospective avenues for novel therapeutic interventions.

Wogonin improves colitis by activating the AhR pathway to regulate the plasticity of ILC3/ILC1

BackgroundIntestinal barrier dysfunction caused by the disrupted balance of group 3 innate lymphoid cells (ILC3)/group 1 innate lymphoid cells (ILC1) is a significant feature in the pathogenesis of inflammatory bowel disease (IBD). Activation of aryl hydrocarbon receptor (AhR) signaling contributes to the maintenance of ILC3/ILC1 balance. Wogonin, a natural flavonoid from Scutellaria baicalensis Georgi, can repair intestinal mucosal damage of IBD. However, it remains unclear if wogonin can exert a therapeutic effect by activating the AhR pathway to regulate the plasticity of ILC3/ILC1. PurposeIn this study, we investigated the immunomodulatory effects of wogonin on IBD and its potential mechanisms in vitro and in vivo. Study design and MethodsChronic colitis was induced by four cycles of 2 % DSS treatment in mice. 20 mg kg-1/day wogonin was administrated by oral gavage and mice were treated intraperitoneally with 10 mg kg-1/2 days CH223191 to block the AhR pathway. Colon tissues were processed for histopathological examination and evaluation of the epithelial barrier function by immunohistochemistry. The activation of the AhR pathway and the plasticity of ILC3/ILC1 were determined by western blot and flow cytometry. Then, we also detected the intestinal microflora and their metabolites by 16 s sequencing and non-targeted Metabolomics analysis. Furthermore, an in vitro culture system consisting of MNK3 cells and NCM460 cells, and a CETSA assay were performed to confirm the molecular mechanism. ResultsWogonin ameliorated histological severity of the colon, decreased the secretion of inflammatory factors, and increased tight junction proteins in colitis mice. These effects are associated with the tendency of conversion from ILC3 to ILC1 prevented by wogonin, which was offset by AhR antagonist CH223191. In addition, wogonin exerted the curative effect by altering gut microbiota to produce metabolites such as Kynurenic acid, and 1H-Indole-3-carboxaldehyde as AhR endogenous ligands. In vitro data further verified that wogonin as an exogenous ligand directly binds to the structural domain of AhR by CETSA. Also, the supernatant of MNK-3 cells stimulated with wogonin enhanced expression of Occludin and Claudin1 in NCM460 cells induced by LPS. ConclusionCumulatively, our study illustrated that wogonin improved the outcomes of DSS-induced chronic colitis via regulating the plasticity of ILC3/ILC1. Its specific mechanism is to binding to AhR directly, and to activate the AhR pathway indirectly by altering the tryptophan metabolisms of gut microbiota.

H2S-Releasing Versatile Montmorillonite Nanoformulation Trilogically Renovates the Gut Microenvironment for Inflammatory Bowel Disease Modulation.

Abnormal activation of the intestinal mucosal immune system, resulting from damage to the intestinal mucosal barrier and extensive invasion by pathogens, contributes to the pathogenesis of inflammatory bowel disease (IBD). Current first-line treatments for IBD have limited efficacy and significant side effects. An innovative H2S-releasing montmorillonite nanoformulation (DPs@MMT) capable of remodeling intestinal mucosal immune homeostasis, repairing the mucosal barrier, and modulating gut microbiota is developed by electrostatically adsorbing diallyl trisulfide-loaded peptide dendrimer nanogels (DATS@PDNs, abbreviated as DPs) onto the montmorillonite (MMT) surface. Upon rectal administration, DPs@MMT specifically binds to and covers the damaged mucosa, promoting the accumulation and subsequent internalization of DPs by activated immune cells in the IBD site. DPs release H2S intracellularly in response to glutathione, initiating multiple therapeutic effects. In vitro and in vivo studies have shown that DPs@MMT effectively alleviates colitis by eliminating reactive oxygen species (ROS), inhibiting inflammation, repairing the mucosal barrier, and eradicating pathogens. RNA sequencing revealed that DPs@MMT exerts significant immunoregulatory and mucosal barrier repair effects, by activating pathways such as Nrf2/HO-1, PI3K-AKT, and RAS/MAPK/AP-1, and inhibiting the p38/ERK MAPK, p65 NF-κB, and JAK-STAT3 pathways, as well as glycolysis. 16S rRNA sequencing demonstrated that DPs@MMT remodels the gut microbiota by eliminating pathogens and increasing probiotics. This study develops a promising nanoformulation for IBD management.

TLR4, IgA and EpCAM Expression in Colorectal Cancer and Their Possible Association with Microbiota as a Pathogenic Factor; An Immunohistochemical and Genetic Study.

The pathogenesis of inflammatory bowel disease (IBD) and colorectal cancer (CRC) is thought to be related to immune response against gut microbiota. TLR4, IgA, and EpCAM have a role in intestinal local immune response and their altered expression related to both IBD and CRC. Lipopolysaccharide (LPS) is the main activator of TLR4. The objective of this study is to evaluate the possible role of intestinal microbiota in the pathogenesis of IBD and CRC through expression of TLR4, IgA and EpCAM. One hundred five cases were divided into (Group 1/ Control: 10 sections of normal colonic mucosa, Group 2/CRC: 51 cases, Group 3/IBD: 44 cases). Immunohistochemistry for TLR4, IgA, and EpCAM was done. LPS was assessed in all groups. TLR4 gene and protein expression were assessed in colorectal cancer cell line by RT-PCR and immunocytochemistry. There was a significant correlation between TLR4 and tumor grade (P value 0.003 and 0.01 respectively). A significant correlation was found between IgA expression and T stage (P value 0.02) and between EpCAM expression and histologic type (P value 0.02). In comparison of CRC patients to controls; there was a statistically significant different expression of TLR4 positivity, IgA positivity and EpCAM (P value <0.001, 0.004, <0.001 respectively). Patients with CRC were compared to colitis patients and there was a statistically significant different expression of IgA positivity and EpCAM expression (P value <0.001). There was significant higher expression of TLR4 in CRC cell line than the fibroblast by both PCR and immunocytochemistry (P-value: 0.003 and 0.024 respectively). LPS level in CRC patients was significantly higher than the control and IBD groups (P values <0.001 and <0.001 respectively). TLR4, IgA, EpCAM expression in both CRC and IBD might be related to the pathogenic role of microbiota and could represent potential prevention modalities and therapeutic targets.