Immunopathogenesis of inflammatory bowel disease and mechanisms of biological therapies

The Role of TGF-β, Activin and Follistatin in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an immune-mediated inflammatory condition predominantly affecting the gastrointestinal (GI) tract. An increasing prevalence of IBD has been observed globally. The pathogenesis of IBD includes a complex interplay between the intestinal microbiome, diet, genetic factors and immune responses. The consequent imbalance of inflammatory mediators ultimately leads to intestinal mucosal damage and defective repair. Growth factors, given their specific roles in maintaining the homeostasis and integrity of the intestinal epithelium, are of particular interest in the setting of IBD. Furthermore, direct targeting of growth factor signalling pathways involved in the regeneration of the damaged epithelium and the regulation of inflammation could be considered as therapeutic options for individuals with IBD. Several members of the transforming growth factor (TGF)-β superfamily, particularly TGF-β, activin and follistatin, are key candidates as they exhibit various roles in inflammatory processes and contribute to maintenance and homeostasis in the GI tract. This article aimed firstly to review the events involved in the pathogenesis of IBD with particular emphasis on TGF-β, activin and follistatin and secondly to outline the potential role of therapeutic manipulation of these pathways.

Mesenchymal Stem Cell-derived Exosomes: Novel Therapeutic Approach for Inflammatory Bowel Diseases

As double membrane-encapsulated nanovesicles (30-150 nm), exosomes (Exos) shuttle between different cells to mediate intercellular communication and transport active cargoes of paracrine factors. The anti-inflammatory and immunomodulatory activities of mesenchymal stem cell (MSC)-derived Exos (MSC-Exos) provide a rationale for novel cell-free therapies for inflammatory bowel disease (IBD). Growing evidence has shown that MSC-Exos can be a potential candidate for treating IBD. In the present review, we summarized the most critical advances in the properties of MSC-Exos, provided the research progress of MSC-Exos in treating IBD, and discussed the molecular mechanisms underlying these effects. Collectively, MSC-Exos had great potential for cell-free therapy in IBD. However, further studies are required to understand the full dimensions of the complex Exo system and how to optimize its effects.

Role of interleukin-6-mediated inflammation in the pathogenesis of inflammatory bowel disease: focus on the available therapeutic approaches and gut microbiome

Inflammatory bowel disease (IBD) is considered a chronic inflammatory and multifactorial disease of the gastrointestinal tract. Crohn's disease (CD) and ulcerative colitis (UC) are two types of chronic IBD. Although there is no accurate information about IBD pathophysiology, evidence suggests that various factors, including the gut microbiome, environment, genetics, lifestyle, and a dysregulated immune system, may increase susceptibility to IBD. Moreover, inflammatory mediators such as interleukin-6 (IL-6) are involved in the immunopathogenesis of IBDs. IL-6 contributes to T helper 17 (Th17) differentiation, mediating further destructive inflammatory responses in CD and UC. Moreover, Th1-mediated responses participate in IBD, and the antiapoptotic IL-6/IL-6 receptor (IL-6R)/signal transducer and activator of transcription 3 (STAT3) signals are responsible for preserving Th1 cells in the site of inflammation. It has been revealed that fecal bacteria isolated from UC-active and UC-remission patients stimulate the hyperproduction of several cytokines, such as IL-6, tumor necrosis factor-α (TNF-α), IL-10, and IL-12. Given the importance of the IL-6/IL-6R axis, various therapeutic options exist for controlling or treating IBD. Therefore, alternative therapeutic approaches such as modulating the gut microbiome could be beneficial due to the failure of the target therapies so far. This review article summarizes IBD immunopathogenesis focusing on the IL-6/IL-6R axis and discusses available therapeutic approaches based on the gut microbiome alteration and IL-6/IL-6R axis targeting and treatment failure.

IBD disease-modifying therapies: insights from emerging therapeutics

Inflammatory bowel disease (IBD) pathogenesis is associated with gut mucosal inflammation, epithelial damage, and dysbiosis leading to a dysregulated gut mucosal barrier. However, the extent and underlying mechanisms remain largely unknown. Current treatment regimens have focused mainly on treating IBD symptoms; however, such treatment strategies do not address mucosal epithelial repair, barrier homeostasis, or intestinal dysbiosis. Although attempts have been made to identify new therapeutic modalities to enhance gut barrier functions, these are at an early developmental stage and have not been wholly successful. We review conventional therapies, the possible relevant role of gut barrier-protecting agents, and biomaterial strategies relating to combination therapies that may pave the way towards developing new therapeutic approaches for IBD.

TIPE-2 ameliorates inflammatory bowel disease in mice via inhibiting STAT3 and NF-kB activation

TIPE-2 has been identified as a negative regulator of both innate and adaptive immunity and is involved in several inflammatory diseases. However, the immune inhibition mechanism of TIPE-2 involved in inflammatory bowel disease has not been well studied. Therefore, the aim of this study was to investigate whether TIPE-2 improved experimental colitis by reducing high levels of inflammation in the intestine. Lentivirus encoding TIPE-2 was administered to mice by intrarectal injection after colitis induction. Histological analysis was used to analyze sections of the intestine. Protein expression induced by STAT3 and NF-κB signaling was analyzed by western blot. We found that TIPE-2 reduced the colitis activity index score and the histological score of the intestine. TIPE-2 also decreased inflammatory cytokine levels in the intestine. Additionally, TIPE-2 inhibited STAT3 and NF-kB activation. These results suggested that TIPE-2 might attenuate inflammation of colitis via inhibiting of STAT3 and NF-kB activation.

Immunometabolism and microbial metabolites at the gut barrier: Lessons for therapeutic intervention in inflammatory bowel disease

The concept of immunometabolism has emerged recently whereby the repolarizing of inflammatory immune cells toward anti-inflammatory profiles by manipulating cellular metabolism represents a new potential therapeutic approach to controlling inflammation. Metabolic pathways in immune cells are tightly regulated to maintain immune homeostasis and appropriate functional specificity. Because effector and regulatory immune cell populations have different metabolic requirements, this allows for cellular selectivity when regulating immune responses based on metabolic pathways. Gut microbes have a major role in modulating immune cell metabolic profiles and functional responses through extensive interactions involving metabolic products and crosstalk between gut microbes, intestinal epithelial cells, and mucosal immune cells. Developing strategies to target metabolic pathways in mucosal immune cells through the modulation of gut microbial metabolism has the potential for new therapeutic approaches for human autoimmune and inflammatory diseases, such as inflammatory bowel disease. This review will give an overview of the relationship between metabolic reprogramming and immune responses, how microbial metabolites influence these interactions, and how these pathways could be harnessed in the treatment of inflammatory bowel disease.

Masticadienonic acid from Chios mastic gum mitigates colitis in mice via modulating inflammatory response, gut barrier integrity and microbiota

BACKGROUND

Chios mastic gum (CMG) is a traditional Greek medicine used to treat a variety of gastrointestinal disorders, including inflammatory bowel disease (IBD). However, the bioactive compounds of CMG and the mechanisms of action for controlling of IBD remain unknown.

PURPOSE

Masticadienonic acid (MDA) is one of the most abundant constituents isolated from CMG. This study aims to investigate the potential effects and underlying mechanisms of MDA in the pathogenesis of colitis.

METHODS

The effects of MDA were evaluated using a dextran sulphate sodium (DSS)-induced acute colitis mouse model. The body and spleen weight and colon length and weight were measured and the clinical symptoms were analysed. Blood samples were collected to analyse the level of serum inflammatory markers. Colon tissues were processed for histopathological examination, evaluation of the epithelial barrier function, and investigation of the probable mechanisms of action. The gut microbiota composition was also studied to determine the mechanism for the beneficial effects of MDA on IBD.

RESULTS

MDA could ameliorate the severity of IBD by increasing the body weight and colon length, reducing spleen weight, disease activity index, and histological score. MDA treatments reduce the release of serum inflammatory cytokines tumour necrosis factor-alpha (TNFα), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6) via inhibiting the MAPK and NF-κB signalling pathways. MDA supplementation could also improve the intestinal barrier function by activating the NF-E2-related factor-2 (Nrf2) signalling pathway and restoring the expression of tight junction proteins zonula occludens-1 (ZO-1) and occludin. In addition, MDA administration modulates the gut microbiota composition in DSS-induced colitis mice.

CONCLUSION

The results indicate that MDA attenuated experimental colitis by restoring intestinal barrier integrity, reducing inflammation, and modulating the gut microbiota. The present study provides novel insights into CMG-mediated remission of IBD and may facilitate the development of preventive and therapeutic strategies for IBD.

Effect of Nicotine on Immune System Function

As a parasympathetic alkaloid and the main substance in cigarette smoke, nicotine modulates the immune system, inhibits innate and acquired immunity and is used in treating many autoimmune diseases. It often stimulates the α7 receptor and causes an anti-inflammatory state in the body. This study is designed to evaluate the role of nicotine treatment on immune system. The results showed that nicotine affects many cells in immune system, alters the downstream intracellular mechanisms and changes lymphocytes polarization. This substance alters TLRs and STATs gene expression and thus changes in the innate immune system. All these events inhibit the secretion of pro-inflammatory cytokines and chemokines which increase angiogenesis and metastasis and exacerbates tumors due to increasing survival and cell growth. Nicotine can aggravate tumors in cancer patients, with many positive effects observed in the treating autoimmune disease, Nicotine treatment function in different conditions depends on factors such as concentration, how it is employed, treatment duration and other conditions such as body conditions affecting the immune system, hence, further studies and review of all conditions are required.

Korean clinical practice guidelines on biologics for moderate to severe Crohn's disease

Crohn's disease (CD) is a relapsing and progressive condition characterized by diarrhea, abdominal pain, weight loss, and hematochezia that results in serious complications such as perforations, fistulas, and abscesses. Various medications, interventions, and surgical treatments have been used to treat CD. The Korean guidelines for CD management were distributed in 2012 and revised in 2017 by the Inflammatory Bowel Disease (IBD) Research Group of the Korean Association for the Study of Intestinal Diseases. Substantial progress in mucosal immunologic research has elucidated the pathophysiology of IBD, leading to development of biological agents for treatment of CD. The first developed biologic agent, tumor necrosis factor-α agents, were shown to be efficacious in CD, heralding a new era in management of CD. Subsequently, vedolizumab, a monoclonal antibody against integrin α4β7, and ustekinumab, a human monoclonal antibody that inhibits the common p40 subunit of interleukin-12 and interleukin-23, were both approved for clinical use and are efficacious and safe for both induction and maintenance of remission in moderate-to-severe CD patients. Moreover, a recent study showed the non-inferiority of CT-P13, an infliximab biosimilar, compared with infliximab in CD patients. The third Korean guidelines for CD management provide updated information regarding treatment of moderate-to-severe CD patients with biologic agents.

TNF-α Enhances the Therapeutic Effects of MenSC-Derived Small Extracellular Vesicles on Inflammatory Bowel Disease through Macrophage Polarization by miR-24-3p

Human menstrual blood-derived mesenchymal stem cells (MenSCs) and their secreted small extracellular vesicles (EVs) had been proven to relieve inflammation, tissue damage, and fibrosis in various organs. The microenvironment induced by inflammatory cytokines can promote mesenchymal stem cells (MSCs) to secrete more substances (including EVs) that could regulate inflammation. Inflammatory bowel disease (IBD) is a chronic idiopathic intestinal inflammation, the etiology and mechanism of which are unclear. At present, the existing therapeutic methods are ineffective for many patients and have obvious side effects. Hence, we explored the role of tumor necrosis factor α- (TNF-α-) pretreated MenSC-derived small EV (MenSCs-sEV^TNF-α ) in a mouse model of dextran sulfate sodium- (DSS-) induced colitis, expecting to find better therapeutic alterations. In this research, the small EVs of MenSCs were obtained by ultracentrifugation. MicroRNAs of small EVs derived from MenSCs before and after TNF-α treatment were sequenced, and the differential microRNAs were analyzed by bioinformatics. The small EVs secreted by TNF-α-stimulating MenSCs were more effective in colonic mice than those secreted directly by MenSCs, as evidenced by the results of histopathology analysis of colonic tissue, immunohistochemistry for tight junction proteins, and enzyme-linked immunosorbent assay (ELISA) for cytokine expression profiles in vivo. The process of MenSCs-sEV^TNF-α relieving colonic inflammation was accompanied by the polarization of M2 macrophages in the colon and miR-24-3p upregulation in small EVs. In vitro, both MenSC-derived sEV (MenSCs-sEV) and MenSCs-sEV^TNF-α reduced the expression of proinflammatory cytokines, and MenSCs-sEV^TNF-α can increase the portion of M2 macrophages. In conclusion, after TNF-α stimulation, the expression of miR-24-3p in small EVs derived from MenSCs was upregulated. MiR-24-3p was proved to target and downregulate interferon regulatory factor 1 (IRF1) expression in the murine colon and then promoted the polarization of M2 macrophages. The polarization of M2 macrophages in colonic tissues then reduced the damage caused by hyperinflammation.

Influence of nutrients and metabolites on the differentiation of plasma cells and implications for autoimmunity

The modulation of inflammatory (auto)immune reactions by nutrients and gut bacterial metabolites is of great interest for potential preventive and therapeutic strategies. B cell-derived plasma cells are major players in inflammatory (auto)immune responses and can exhibit pro- or anti-inflammatory effects through (auto)antibody-dependent and -independent functions. Emerging evidence indicates a key role of nutrients and microbial metabolites in regulating the differentiation of plasma cells as well as their differentiation to pro- or anti-inflammatory phenotypes. These effects might be mediated indirectly by influencing other immune cells or directly through B cell-intrinsic mechanisms. Here, we provide an overview of nutrients and metabolites that influence B cell-intrinsic signaling pathways regulating B cell activation, plasma cell differentiation, and effector functions. Furthermore, we outline important inflammatory plasma cell phenotypes whose differentiation could be targeted by nutrients and microbial metabolites. Finally, we discuss possible implications for inflammatory (auto)immune conditions.

Deciphering the role of autophagy in the immunopathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a typical immune-mediated chronic inflammatory disorder. Following the industrialization and changes in lifestyle, the incidence of IBD in the world is rising, which makes health concerns and heavy burdens all over the world. However, the pathogenesis of IBD remains unclear, and the current understanding of the pathogenesis involves dysregulation of mucosal immunity, gut microbiome dysbiosis, and gut barrier defect based on genetic susceptibility and environmental triggers. In recent years, autophagy has emerged as a key mechanism in IBD development and progression because Genome-Wide Association Study revealed the complex interactions of autophagy in IBD, especially immunopathogenesis. Besides, autophagy markers are also suggested to be potential biomarkers and target treatment in IBD. This review summarizes the autophagy-related genes regulating immune response in IBD. Furthermore, we explore the evolving evidence that autophagy interacts with intestinal epithelial and immune cells to contribute to the inflammatory changes in IBD. Finally, we discuss how novel discovery could further advance our understanding of the role of autophagy and inform novel therapeutic strategies in IBD.

Polyphenols and inflammatory bowel disease: Natural products with therapeutic effects?

Inflammatory bowel disease (IBD) is a long-life disease with periods of recurrence and relief. Oxidative stress plays an important role in the pathogenesis of this disease. Recent years' studies in the field of IBD treatment mostly have focused on targeting cytokines and immune cell trafficking using antibodies and inhibitors, altering the composition of intestinal bacteria in the line of attenuation of inflammation using probiotics and prebiotics, and attenuating oxidative stress through antioxidant supplementation. Studies in animal models of IBD have shown that some polyphenolic compounds including curcumin, quercetin, resveratrol, naringenin, and epigallocatechin-3-gallate can affect almost all of the above aspects and are useful compounds in the treatment of IBD. Clinical studies performed on IBD patients have also confirmed the findings of animal model studies and have shown that supplementation with some of the above-mentioned polyphenolic compounds has positive effects in reducing disease clinical and endoscopic activity, inducing and maintaining remission, and improving quality of life. In this review article, in addition to a detailed reviewing the effects of the above-mentioned polyphenolic compounds on the events involved in the pathogenesis of IBD, the results of these clinical studies will also be reviewed.

Quality assessment of Clinical Practice Guidelines (CPG) for the diagnosis and treatment of inflammatory bowel disease using the AGREE II instrument: a systematic review

BACKGROUND

The incidence and diagnosis of inflammatory bowel disease (IBD) has increased considerably in recent years. Many clinical practice guidelines (CPG) have been developed for the management of this disease across different clinical contexts, however, little evidence exists on their methodological quality. Therefore, we aimed to systematically evaluate the quality of CPGs for the diagnosis and treatment of IBD using the Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument.

METHODS

We identified CPGs by searching databases (MEDLINE - PubMed, EMBASE, CINAHL, LILACS) and other sources of gray literature on January 2022. We included guidelines with specific recommendations for the diagnosis and treatment of IBD and evaluated them with the AGREE II instrument to assess their methodological quality. Six independent reviewers assessed the quality of the guidelines and resolved conflicts by consensus. We assessed the degree of agreement using the intraclass correlation coefficient (ICC) and change in quality over time was appraised in two periods: from 2012 to 2017 and from 2018 to 2022.

RESULTS

We analyzed and evaluated 26 CPGs that met the inclusion criteria. The overall agreement among reviewers was moderate (ICC: 0.74; 95% CI 0.36 - 0.89). The mean scores of the AGREE II domains were: "Scope and purpose" 84.51%, "Stakeholder involvement" 60.90%, "Rigor of development" 69.95%, "Clarity of presentation" 85.58%, "Applicability" 26.60%, and "Editorial independence" 62.02%. No changes in quality were found over time.

CONCLUSIONS

The quality of the CPGs evaluated was generally good, with a large majority of the assessed guidelines being "recommended" and "recommended with modifications"; despite this, there is still room for improvement, especially in terms of stakeholder involvement and applicability. Efforts to develop high quality CPGs for IBD need to be further optimized.

Protective Effect of Dietary Polysaccharides from Yellow Passion Fruit Peel on DSS-Induced Colitis in Mice

Inflammatory bowel disease (IBD) is a complex inflammatory disorder characterized by chronic and spontaneously relapsing inflammation of the gastrointestinal tract. IBD includes two idiopathic disorders: Crohn’s disease (CD) and ulcerative colitis (UC). In particular, UC causes inflammation and ulceration of the colon and rectum. There is no cure for UC. The pharmacological treatment is aimed at controlling and/or reducing the inflammatory process and promoting disease remission. The present study investigated the possible protective effects of soluble dietary fiber (SDF) isolated from yellow passion fruit peel in the dextran sulfate sodium- (DSS-) induced colitis model in mice, induced by 5% of DSS. The animals were treated with SDF (10, 30, or 100 mg/kg (po)), and the disease activity index was monitored. Colon tissues were collected, measured, and prepared for oxidative stress, inflammation, and histology analysis. SDF improved body weight loss, colon length, and disease activity index and prevented colonic oxidative stress by regulating GSH levels and SOD activity. Furthermore, SDF reduced colonic MPO activity, TNF-α, and IL-1β levels and increased IL-10 and IL-6 levels. As observed by histological analysis, SDF treatment preserved the colonic tissue, the mucus barrier, and reduced inflammatory cell infiltration. Although this is a preliminary study, taken together, our data indicate that SDF may improve the course of DSS-UC. More studies are needed to explore and understand how SDF promotes this protection.

Protective effects of sigma 1 receptor agonist PRE084 on 2,4,6-trinitrobenzene sulfonic acid-induced experimental colitis in mice

Purpose

We aimed to investigate the protective effect of sigma 1 receptor agonist and antagonist, PRE084 and BD1047, respectively, on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice.

Methods

Thirty male ICR mice were randomly divided into 5 groups: control, 50% ethanol, colitis, PRE084 + colitis, and combined (PRE084 + BD1047 + colitis). Colitis was induced by intrarectal administration of TNBS. PRE084 and BD1047 were injected daily, starting 3 days before colitis induction. Distal colon tissue was excised for histopathological evaluation, and levels of glutathione (GSH), superoxide dismutase (SOD), myeloperoxidase (MPO), and lipid peroxidation were determined.

Results

Colitis caused weight loss, mucosal damage, upregulation of tumor necrosis factor-α, interleukin (IL)-1β, IL-6, MPO, and thiobarbituric acid reactive substance activities, and downregulation of GSH and SOD activities. These changes caused by TNBS-induced colitis were significantly ameliorated by PRE084 pretreatment. However, the combined pretreatment with BD1047 significantly attenuated the protective effect of PRE084, thereby reverting to the colitis-induced state.

Conclusion

We conclude that the sigma 1 receptor agonist PRE084 exhibits significant protective effects against TNBS-induced colitis, which appears to be at least partly mediated by the inhibition of inflammation and oxidative stress, and enhancement of antioxidant properties. Collectively, these results suggest that PRE084 might be an effective drug for the treatment of ulcerative colitis.

A Review on Inflammatory Bowel Diseases: Recent Molecular Pathophysiology Advances

Inflammatory bowel diseases are considered immune disorders with a complex genetic architecture involving constantly changing endogenous and exogenous factors. The rapid evolution of genomic technologies and the emergence of newly discovered molecular actors are compelling the research community to reevaluate the knowledge and molecular processes. The human intestinal tract contains intestinal human microbiota consisting of commensal, pathogenic, and symbiotic strains leading to immune responses that can contribute and lead to both systemic and intestinal disorders including IBD. In this review, we attempted to highlight some updates of the new IBD features related to genomics, microbiota, new emerging therapies and some major established IBD risk factors.

Expression of CD44 in Leukocyte Subpopulations in Patients with Inflammatory Bowel Diseases

CD44 expressed in monocytes and lymphocytes seems to play a crucial role in gastrointestinal inflammation, such as the one occurring in the context of inflammatory bowel diseases. Differentially methylated genes are distinctly expressed across monocyte subpopulations related to the state of Crohn’s disease. Hence, the aim of this study was to detect CD44 expression in leukocyte subpopulations in relation to the type of IBD, therapy, and disease duration. Monocyte subpopulations CD14++CD16−, CD14++CD16++, and CD14+CD16+ as well as other leukocytes were analyzed for their CD44 expression using flow cytometry in 46 patients with IBD and 48 healthy controls. Patients with Crohn’s disease treated with non-biological therapy (NBT) exhibited a lower percentage of anti-inflammatory CD14+CD16++ monocytes, whereas NBT-treated patients with ulcerative colitis had lower expression of CD44 on CD14+CD44+ lymphocytes in comparison to controls, respectively. Conversely, patients with Crohn’s disease treated with biological therapy had a higher percentage of CD44+ granulocytes but lower expression of CD44 on anti-inflammatory monocytes compared to controls. Median fluorescence intensity (MFI) of CD44 on CD44+CD14+ lymphocytes was higher in ulcerative colitis patients treated with biological therapy compared to NBT. The percentage of classical CD14++CD16− monocytes was lower in the <9 years of IBD duration subgroup compared with the longer disease duration subgroup. The present study addresses the putative role of differentiation and regulation of leukocytes in tailoring IBD therapeutic regimes.

Renshen Baidu Powder Attenuated Intestinal Inflammation and Apoptosis in Ulcerative Colitis Rats through the Inhibition of PI3K/AKT/NF-κB Signaling Pathway

OBJECTIVE

Renshen Baidu Powder (RBP) is a famous classic compound of traditional Chinese medicine (TCM) and is commonly used for treating ulcerative colitis (UC). However, the pharmacological mechanism of RBP in treating UC remains unclear. This study investigates the possible mechanism of RBP for UC treatment by network pharmacological analysis and rat validation.

METHODS

First, the main chemical constituents of RBP were identified using ultrahigh-performance liquid chromatography quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap-HRMS). Then, we obtained targets of identified compounds from the SwissTargetPrediction database and targets associated with UC from GeneCards database. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to analyze the metabolism-related signaling pathways affected by RBP. Hematoxylin-eosin (HE) staining was used to observe the pathological change of colon in UC rats after treating RBP, and terminal deoxynucleotidyl-transferase (TdT)-mediated dUTP Nick end labeling (TUNEL) staining was used to detect apoptosis after RBP treatment. The enzyme-linked immunosorbent assay (ELISA) was employed to evaluate cytokine levels of TNF-α, IL-1β, and IL-6. The protein expressions of Bax, Bcl-2, PI3K, AKT, and NF-κB in colonic tissue were detected using immunohistochemistry (IHC). Real-time quantitative polymerase chain reaction (RT-QPCR) was employed to evaluate mRNA expression of PI3K, AKT, and NF-κB.

RESULTS

We found a total of 24 main compounds and 329 potential targets related to UC. According to KEGG results, 3 main pathways were identified as responsible for UC, including PI3K-AKT, HIF-1, and VEGF signaling pathway. Animal experiments showed that RBP treatment significantly attenuated colon damage in rats with UC. Mechanistically, RBP could inhibit PI3K/AKT/NF-κB pathway; decrease cell apoptosis; and downregulate the expression of TNF-α, IL-1β, and IL-6.

CONCLUSIONS

This study demonstrated that RBP may exert anti-inflammatory and antiapoptotic therapeutic benefits in UC by regulating the PI3K/AKT/NF-κB signaling pathways, providing a scientific basis for understanding the mechanism of RBP against UC.

Downregulated Mucosal Autophagy, Alpha Kinase-1 and IL-17 Signaling Pathways in Active and Quiescent Ulcerative Colitis

Background

Improved mucosal immune profiling in active and quiescent colonic inflammatory bowel disease (IBD) is needed to develop therapeutic options for treating and preventing flares. This study therefore aimed to provide a comprehensive mucosal characterization with emphasis on immunological host response of patients with active ulcerative colitis (UC active), UC during remission (UC remission) and active colonic Crohn’s disease (CD active).

Methods

Colonic biopsies from 47 study subjects were collected for gene expression and pathway analyses using the NanoString host-response panel, including 776 genes and 56 immune-related pathways.

Results

The majority of mucosal gene expression and signaling pathway scores were increased in active IBD (n=27) compared to healthy subjects (n=10). However, both active IBD and UC remission (n=10) demonstrated decreased gene expression and signaling pathway scores related to autophagy, alpha kinase-1 and IL-17 signaling pathways compared to healthy subjects. Further, UC remission was characterized by decreased scores of several signaling pathways linked to homeostasis along with increased mononuclear cell migration pathway score as compared to healthy subjects. No major differences in the colonic mucosal gene expression between CD active (n=7) and UC (n=20) active were observed.

Conclusion

This study indicates that autophagy, alpha kinase-1 and IL-17 signaling pathways are persistently downregulated in UC irrespective of disease activity. Further, UC patients in remission present a unique mucosal environment, potentially preventing patients from reaching and sustaining true homeostasis. These findings may enable better comprehension of the remitting and relapsing pattern of colonic IBD and guide future treatment and prevention of flares.

Elucidating the Role of Innate and Adaptive Immune Responses in the Pathogenesis of Canine Chronic Inflammatory Enteropathy-A Search for Potential Biomarkers

Simple Summary

Canine chronic inflammatory enteropathy (CIE) is a chronic disease affecting the small or large intestine and, in some cases, the stomach of dogs. This gastrointestinal disorder is common and is characterized by recurrent vomiting, diarrhea, and weight loss in affected dogs. The pathogenesis of IBD is not completely understood. Similar to human IBD, potential disease factors include genetics, environmental exposures, and dysregulation of the microbiota and the immune response. Some important components of the innate and adaptive immune response involved in CIE pathogenesis have been described. However, the immunopathogenesis of the disease has not been fully elucidated. In this review, we summarized the literature associated with the different cell types and molecules involved in the immunopathogenesis of CIE, with the aim of advancing the search for biomarkers with possible diagnostic, prognostic, or therapeutic utility.

Abstract

Canine chronic inflammatory enteropathy (CIE) is one of the most common chronic gastrointestinal diseases affecting dogs worldwide. Genetic and environmental factors, as well as intestinal microbiota and dysregulated host immune responses, participate in this multifactorial disease. Despite advances explaining the immunological and molecular mechanisms involved in CIE development, the exact pathogenesis is still unknown. This review compiles the latest reports and advances that describe the main molecular and cellular mechanisms of both the innate and adaptive immune responses involved in canine CIE pathogenesis. Future studies should focus research on the characterization of the immunopathogenesis of canine CIE in order to advance the establishment of biomarkers and molecular targets of diagnostic, prognostic, or therapeutic utility.

IBD therapeutics: what is in the pipeline?

Inflammatory bowel disease (IBD) is an idiopathic long-term relapsing and remitting disorder including ulcerative colitis and Crohn's disease. The aim of therapy is to induce and maintain remission. Anti-TNF therapies dramatically improved clinical outcomes but primary failure or secondary loss is a common problem as well as potential side effects potentially limiting efficacy and long-term use. The advent of new targeted agents with the potential for greater safety is welcomed in IBD and offers the potential for different agents as the disease becomes refractory or even combination therapies to maximise effectiveness without compromising safety in the future. More data are required to understand the best positioning in pathways and longer-term safety effects.

Involvement of Proinflammatory Arachidonic Acid (ARA) Derivatives in Crohn’s Disease (CD) and Ulcerative Colitis (UC)

Recently, an increase in the incidence of inflammatory bowel disease (IBD) has been observed, especially among children and adolescents. Currently, few studies focus on the differentiation of inflammation in IBD subunits, i.e., Crohn’s Disease (CD) and Ulcerative Colitis (UC). The aim of this study was to compare the concentrations of proinflammatory mediators of arachidonic acid (ARA) and linoleic acid (LA) in patients with CD (n = 34) and UC (n = 30), in order to identify differences in inflammation in both diseases and within the same entity, according to disease activity. Sixty-four adolescents with a mean age of 13.76 ± 2.69 and 14.15 ± 3.31, for CD and UC, respectively, were enrolled in the study. Biochemical analysis of ARA and LA derivatives was performed using a liquid chromatography. A trend was observed in the concentration of 15S-HETE (hydroxyeicosatetraenoic acids) in CD relative to UC. The active phase of both diseases showed a higher 15S-HETE concentration in active CD relative to active UC. Comparing patients with CD with active and inactive disease showed a trend of increased levels of thromboxane B2, leukotriene B4 and 9S-HODE (hydroxyoctadecadienoic acid) in the active versus the inactive disease. We also observed statistically significantly higher levels of 12S-HETE in inactive CD relative to active CD. In the UC group, on the other hand, statistically significantly higher levels of prostaglandin E2 and 16RS-HETE were observed in active UC relative to inactive UC. Moreover, significantly higher concentrations of LTX A4 5S, 6R were observed in inactive UC relative to the active phase. In conclusion, the present study indicated the activity of the 15-LOX pathway in CD. Further studies involving lipid mediators in patients with IBD may contribute to the development of new therapies for the treatment of IBD. The identification of differences in the course of inflammation may help to target therapy in CD and UC, and perhaps allow the introduction of an additional diagnostic marker between the two main IBD subtypes.

Atractylenolide III inhibits epithelial‑mesenchymal transition in small intestine epithelial cells by activating the AMPK signaling pathway

Compared with the available drugs for the treatment of fibrosis in other organs, the development of intestinal anti-fibrosis drugs is limited. Therefore, it is of practical significance to examine novel drugs to delay or block the development of intestinal fibrosis. The present study aimed to investigate the effect of atractylenolide III (ATL-III) on intestinal fibrosis. An MTT assay was used to detect the effect of ATL-III on the activity of IEC-6 cells. The migration and invasion of fibrotic cells stimulated with TGF-β were determined via wound healing and Transwell assays. An immunofluorescence assay and western blotting were conducted to assess the expression levels of protein associated with epithelial-mesenchymal transition (EMT). The role of the AMP-activated protein kinase (AMPK) pathway was verified using compound C (an AMPK inhibitor) treatment. The results of the present study indicated that ATL-III had no effect on the cells at a dose of 1–20 µmol/l. Moreover, ATL-III can inhibit the invasion and migration of cells induced by TGF-β1, as well as block the EMT process. It was found that ATL-III could also activate the AMPK pathway. Furthermore, compound C reduced the inhibitory effect of ATL-III on stimulated cells, which indicated that the AMPK pathway plays a role in the inhibition process. In conclusion, ATL-III may inhibit the EMT of IEC-6 cells stimulated with TGF-β1 by activating the AMPK signaling pathway.

Targeting Chronic Inflammation of the Digestive System in Cancer Prevention: Modulators of the Bioactive Sphingolipid Sphingosine-1-Phosphate Pathway

Incidence of gastrointestinal (GI) cancers is increasing, and late-stage diagnosis makes these cancers difficult to treat. Chronic and low-grade inflammation are recognized risks for most GI cancers. The GI mucosal immune system maintains healthy homeostasis and signalling molecules made from saturated fats, bioactive sphingolipids, play essential roles in healthy GI immunity. Sphingosine-1-phosphate (S1P), a bioactive sphingolipid, is a key mediator in a balanced GI immune response. Disruption in the S1P pathway underlies systemic chronic metabolic inflammatory disorders, including diabetes and GI cancers, providing a strong rationale for using modulators of the S1P pathway to treat pathological inflammation. Here, we discuss the effects of bioactive sphingolipids in immune homeostasis with a focus on S1P in chronic low-grade inflammation associated with increased risk of GI carcinogenesis. Contemporary information on S1P signalling involvement in cancers of the digestive system, from top to bottom, is reviewed. Further, we discuss the use of novel S1P receptor modulators currently in clinical trials and their potential as first-line drugs in the clinic for chronic inflammatory diseases. Recently, ozanimod (Zeposia^TM) and etrasimod have been approved for clinical use to treat ulcerative colitis and eosinophilic oesophagitis, respectively, which may have longer term benefits in reducing risk of GI cancers.

New translational and experimental insights into the role of pro-resolving lipid mediators in inflammatory bowel disease

The resolution of inflammation is an active process, guided by specialized pro-resolution lipid mediators (SPMs). These mediators originate from polyunsaturated fatty acids, such as omega-3. Sufficient evidence suggests that the beneficial effects attributed to omega-3 are, at least in part, the result of the immunomodulatory action of the SPMs, which act systemically by overcoming inflammation and repairing tissue damage, without suppressing the immune response. Recent studies suggest that an imbalance in the synthesis and/or activity of these compounds may be associated with the pathogenesis of several inflammatory conditions, such as inflammatory bowel disease (IBD). Thus, this review highlights the advances made in recent years with regard to the endo-genous synthesis and the biological role of lipoxins, resolvins, protectins, and maresins, as well as their precursors, in the regulation of inflammation; and provides an update on the participation of these mediators in the development and evolution of IBD and the therapeutic approaches that these immunomodulating substances are involved in this context.

Trifolium pratense ethanolic extract alters the gut microbiota composition and regulates serum lipid profile in the ovariectomized rats

Background

Trifolium pratense (red clover) ethanolic extract (TPEE) has been used as a popular over-the-counter remedy for the management of menopausal symptoms. Prolonged consumption of herbal extract has been shown to regulate the composition of gut microbiota. This study was designed to elucidate the influence of TPEE on the gut microbiota composition in the ovariectomized (OVX) rats.

Methods

OVX rats were treated with TPEE at 125, 250, 500 mg/kg/day, or controls (pomegranate extract, 500 mg/kg/day; estradiol, 25 μg/kg/day) for 12 weeks. Gut microbiota analysis was conducted by extracting the microbial DNA from fecal samples and microbiome taxonomic profiling was carried out by using next-generation sequencing. The levels of serum biomarkers were analyzed using enzyme-linked immunosorbent assay (ELISA) kit. The prediction of functional biomarker of microbiota was performed using PICRUSt to investigate the potential pathways associated with gut health and serum lipid profile regulation. To study the correlation between gut microbiota composition and serum lipid levels, Spearman’s correlation coefficients were defined and analyzed. Additionally, gas chromatography–mass spectrometry analysis was conducted to uncover additional physiologically active ingredients.

Results

TPEE-treated OVX rats showed significant reduction in serum triglycerides (TG), total cholesterols (TCHOL), and LDL/VLDL levels but increase in HDL level. The alteration in the pathways involve in metabolism was the most common among the other KEGG categories. Particularly, TPEE also significantly reduced the relative abundance of sequences read associated with inflammatory bowel disease (IBD) and the peroxisome proliferator-activated receptor (PPAR) signalling pathway. TPEE intervention was seen to reduce the Firmicutes to Bacteroidetes (F/B) ratio in the OVX rats, denoting a reduction in microbial dysbiosis in the OVX rats. Correlation analysis at the phylum level revealed that Bacteriodetes and Proteobacteria were strongly correlated with serum TG, TCHOL and HDL levels. At the species level, Bifidobacterium pseudolongum group was seen to positively correlate with serum HDL level and negatively correlated with serum AST, ALT, LDL/VLDL, TCHOL, and TG levels.

Conclusions

TPEE treatment showed therapeutic benefits by improving the intestinal microbiota composition which strongly correlated with the serum lipid and cholesterol levels in the OVX rats.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03486-w.

Immunological Aspect in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammation in the alimentary tract due to improper immune response toward external and internal antigens. The disease consists of 2 entities: ulcerative colitis (UC) and Crohn’s disease (CD). The disease’s prevalence is increasing worldwide due to westernization and industrialization. Europe still holds the highest prevalence of IBD in the world. There are 2 peaks of disease incidence. The first is in the third decade of life and the second is in the fourth decade. Slight male predominance is observed in IBD. Internal and external risk factors play important role in the occurrence of IBD including genetic, smoking, reduced fibre intake, less or absent breastfeeding, sedentary occupation, pollution exposure, and medications. The disease carries heavy economic burden and hampers patient’s quality of life. The immune concept of IBD was hypothesized in 1950s since the symptoms resolved with the administration of steroid. Innate and adaptive immune systems are involved in the pathogenesis of IBD. Antigen presenting cells are found hyperactive, intestinal barrier is disrupted, and autophagy activity is increased. Molecular mimicry occurs between foreign and self antigen. The activity of T helper (Th)1, Th2, and Th17 is amplified while regulatory T cell’s activity is suppressed. Pro-inflammatory cytokine production is elevated but anti-inflammatory cytokines is lowered. Finally, there is increased immunoglobulin G level in intestinal mucosa and imbalance of gut microorganism. All the above immune disturbances lead to chronic inflammation in IBD.

Cytokines and Biologic Therapy in Patients with Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are chronic inflammatory disorders, including Crohns’ disease (CD) and ulcerative colitis (UC), both characterized by a clinical relapsing course and an immune-mediated pathogenesis [...]

MicroRNA-497 inhibits inflammation in DSS-induced IBD model mice and lipopolysaccharide-induced RAW264.7 cells via Wnt/β-catenin pathway

BACKGROUND AND AIMS

MicroRNA (miR)-497 is downregulated in several inflammatory diseases, excluding inflammatory bowel disease (IBD). The aim of this study is to evaluate whether miR-497 inhibits gut inflammation both in vivo and in vitro.

METHODS

The 3% dextran sulphate sodium (DSS) was used to induce experimental colitis, while 1 μg/ml lipopolysaccharide (LPS) was for RAW264.7 cell damage.Colitis severity was evaluated by disease activity index (DAI), colon length, histopathologic injury, etc. The nuclear transcription factor NF-κB activity in colon tissues was also estimated by western blot. Then, the quantitative real-time polymerase chain reaction (qRT-PCR) was performed to evaluate the expression levels of miR-497, pro-inflammatory cytokines and chemokines in colon tissues and RAW264.7 cells. Furthermore, the activity of Wnt/β-catenin pathway was determined by western blot and TOP/FOP-flash reporter assays.

RESULTS

The level of miR-497 was reduced in inflamed mucosa from IBD patients, mice with colitis and LPS-treated RAW264.7 cells. miR-497 knockout (miR-497 KO) mice were more susceptible to DSS-induced colitis, with increased inflammatory response, compared with control mice. Furthermore, the overexpression of miR-497 reduced the release of pro-inflammatory cytokines and chemokines in LPS-treated RAW264.7 cells. Finally, we found that miR-497 inhibited inflammation through Wnt/β-catenin pathway both in vitro and in vivo.

CONCLUSION

Our data indicate that miR-497 inhibits inflammation in DSS-induced IBD model mice and LPS-induced RAW264.7 cells by inhibiting the activation of NF-κB pathway and the release of cytokines, indicating that miR-497 plays a key role in the progression of IBD. Thus, therapeutic regulation of miR-497 expression may be beneficial for the treatment of IBD.

Periodontitis Salivary Microbiota Worsens Colitis

Evidence suggests that periodontitis contributes to the pathogenesis of inflammatory bowel disease, including Crohn's disease and ulcerative colitis. However, few studies have examined the role of swallowing and saliva in the pathogenesis of gastrointestinal diseases. Saliva contains an enormous number of oral bacteria and is swallowed directly into the intestine. Here, we explored the influence of periodontitis salivary microbiota on colonic inflammation and possible mechanisms in dextran sulfate sodium (DSS)-induced colitis. The salivary microbiota was collected from healthy individuals and those with periodontitis and gavaged to C57BL/6 mice. Periodontitis colitis was induced by DSS for 5 d and ligature for 1 wk. The degree of colon inflammation was evaluated through hematoxylin and eosin staining, ELISA, and quantitative real-time polymerase chain reaction. Immune parameters were measured with quantitative real-time polymerase chain reaction, flow cytometry, and immunofluorescence. The gut microbiota and metabolome analyses were performed via 16S rRNA gene sequencing and liquid chromatography-mass spectrometry. Although no significant colitis-associated phenotypic changes were found under physiologic conditions, periodontitis salivary microbiota exacerbated colitis in a periodontitis colitis model after DSS induction. The immune response more closely resembled the pathology of ulcerative colitis, including aggravated macrophage M2 polarization and Th2 cell induction (T helper 2). Inflammatory bowel disease-associated microbiota, such as Blautia, Helicobacter, and Ruminococcus, were changed in DSS-induced colitis after periodontitis salivary microbiota gavage. Periodontitis salivary microbiota decreased unsaturated fatty acid levels and increased arachidonic acid metabolism in DSS-induced colitis, which was positively correlated with Aerococcus and Ruminococcus, suggesting the key role of these metabolic events and microbes in the exacerbating effect of periodontitis salivary microbiota on experimental colitis. Our study demonstrated that periodontitis contributes to the pathogenesis of colitis through the swallowing of salivary microbiota, confirming the role of periodontitis in systemic disease and providing new insights into the etiology of gastrointestinal inflammatory diseases.

Selective Tyrosine Kinase 2 Inhibition for Treatment of Inflammatory Bowel Disease: New Hope on the Rise

Conventional systemic and biologic agents are the mainstay of inflammatory bowel disease (IBD) management; however, many of these agents are associated with loss of clinical response, highlighting the need for effective, novel targeted therapies. Janus kinase (JAK) 1-3 and tyrosine kinase 2 (TYK2) mediate signal transduction events downstream of multiple cytokine receptors that regulate targeted gene transcription, including the interleukin-12, interleukin-23, and type I interferon receptors for TYK2. This review summarizes the role of TYK2 signaling in IBD pathogenesis, the differential selectivity of TYK2 inhibitors, and the potential clinical implications of TYK2 inhibition in IBD. A PubMed literature review was conducted to identify studies of JAK1-3 and TYK2 inhibitors in IBD and other immune-mediated inflammatory diseases. Key efficacy and safety information was extracted and summarized. Pan-JAK inhibitors provide inconsistent efficacy in patients with IBD and are associated with toxicities resulting from a lack of selectivity at therapeutic dosages. Selective inhibition of TYK2 signaling via an allosteric mechanism, with an agent that binds to the regulatory (pseudokinase) domain, may reduce potential toxicities typically associated with JAK1-3 inhibitors. Deucravacitinib, a novel, oral, selective TYK2 inhibitor, and brepocitinib and PF-06826647, TYK2 inhibitors that bind to the active site in the catalytic domain, are in development for IBD and other immune-mediated inflammatory diseases. Allosteric TYK2 inhibition is more selective than JAK1-3 inhibition and has the potential to limit toxicities typically associated with JAK1-3 inhibitors. Future studies will be important in establishing the role of selective, allosteric TYK2 inhibition in the management of IBD.

SETD8 involved in the progression of inflammatory bowel disease via epigenetically regulating p62 expression

BACKGROUND AND AIM

Epigenetic modification is an important part of the pathogenesis of inflammatory bowel disease (IBD). Some studies proved that p62 was involved in inflammatory response and upregulated in IBD patients, and histone modification plays an important role in regulating p62 expression. SETD8, a histone H4K20 methyltransferase, has been reported downregulated in some inflammatory diseases. Here, we investigated the role of SETD8 in the development of IBD and its underlying mechanisms.

METHODS

An inflammatory cell model was established to elucidate whether SETD8 involved in inflammatory response in macrophages. Three percent dextran sodium sulfate-induced colitis murine model injection with SETD8 inhibitor was used in our study to investigate whether SETD8 inhibition can affect the progress of IBD. The expression of SETD8 and p62 was measured by qRT-PCR and western blot. The mRNA level of inflammatory cytokines was analyzed by qRT-PCR. In addition, chromatin immunoprecipitation-PCR was performed to identify the mechanism by which SETD8 regulates p62.

RESULTS

SETD8 expression obviously decreased in vitro, in vivo models and in IBD patients. In lipopolysaccharide-activated RAW264.7 cells, knockdown of SETD8 significantly increased the mRNA expression of inducible nitric oxide synthase, cyclooxygenase-2, TNF-α, IL-6, IL-1β, and MCP-1. Based on the dataset, we verified that p62 was a target gene of SETD8 and chromatin immunoprecipitation-PCR assay identified that silence of SETD8 distinctly decreases the H4K20me1 enrichment in the promoter of p62. Moreover, silencing of p62 partly reverses the SETD8 inhibition-mediated pro-inflammatory effect in vitro. Finally, SETD8 pharmacological inhibitor (UNC0379) aggravated the disease progression in dextran sodium sulfate-induced murine colitis.

CONCLUSION

Our findings elucidate an epigenetic mechanism by which SETD8 regulates the p62 expression and restrains the inflammatory response in colitis. Our result suggests that targeting SETD8 may be a promising therapy for IBD.

Infection by Strongyloides venezuelensis attenuates chronic colitis induced by Dextran Sodium Sulfate ingestion in BALB/c mice

Inflammatory bowel diseases (IBD) are chronic health problems of difficult management and treatment. Epidemiological studies indicate an inverse association between helminth infections and IBD, and experimental data confirm that helminth infections modulate the severity of experimental acute colitis in mice. However, the effects of helminth infections on chronic colitis, which is clinically more relevant, have been poorly explored. Herein, we investigated whether Strongyloides venezuelensis infection in BALB/c mice can ameliorate chronic colitis induced by the ingestion of water containing 2.5% Dextran Sodium Sulfate (DSS) over three seven-day treatment cycles, with an interval of fourteen days between cycles. Infected-only, DSS-exposed-only, and non-exposed/uninfected experimental groups served as controls for comparing the severity of colitis and intestinal inflammation among different groups. Our data showed that S. venezuelensis infection in mice with DSS-induced chronic colitis reduced clinical signs, attenuated colon shortening and inflammation, and prevented mucus ablation. The modulatory effect was accompanied by a low concentration of IFN-γ, high concentrations of TGF-β, IL-22, and IL-33 in the colon, and a significant increase of the percentage of CD4+CD25+Foxp3+ Treg cells in the mesenteric lymph node (MLN). In conclusion, S. venezuelensis infection can reduce the severity of DSS-induced chronic colitis in mice possibly through the stimulation of Treg cells and modulatory cytokines, and induction of mucosal repair mechanisms.

Common contributing factors to COVID-19 and inflammatory bowel disease

The devastating complications of coronavirus disease 2019 (COVID-19) result from an individual's dysfunctional immune response following the initial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Multiple toxic stressors and behaviors contribute to underlying immune system dysfunction. SARS-CoV-2 exploits the dysfunctional immune system to trigger a chain of events ultimately leading to COVID-19. We have previously identified many contributing factors (CFs) (representing toxic exposure, lifestyle factors and psychosocial stressors) common to myriad chronic diseases. We hypothesized significant overlap between CFs associated with COVID-19 and inflammatory bowel disease (IBD), because of the strong role immune dysfunction plays in each disease. A streamlined dot-product approach was used to identify potential CFs to COVID-19 and IBD. Of the fifty CFs to COVID-19 that were validated for demonstration purposes, approximately half had direct impact on COVID-19 (the CF and COVID-19 were mentioned in the same record; i.e., CF---→COVID-19), and the other half had indirect impact. The nascent character of the COVID-19 core literature (∼ one year old) did not allow sufficient time for the direct impacts of many CFs on COVID-19 to be identified. Therefore, an immune system dysfunction (ID) literature directly related to the COVID-19 core literature was used to augment the COVID-19 core literature and provide the remaining CFs that impacted COVID-19 indirectly (i.e., CF---→immune system dysfunction---→COVID-19). Approximately 13000 potential CFs for myriad diseases (obtained from government and university toxic substance lists) served as the starting point for the dot-product identification process. These phrases were intersected (dot-product) with phrases extracted from a PubMed-derived IBD core literature, a nascent COVID-19 core literature, and the COVID-19-related immune system dysfunction (ID) core literature to identify common ID/COVID-19 and IBD CFs. Approximately 3000 potential CFs common to both ID and IBD, almost 2300 potential CFs common to ID and COVID-19, and over 1900 potential CFs common to IBD and COVID-19 were identified. As proof of concept, we validated fifty of these ∼3000 overlapping ID/IBD candidate CFs with biologic plausibility. We further validated 24 of the fifty as common CFs in the IBD and nascent COVID-19 core literatures. This significant finding demonstrated that the CFs indirectly related to COVID-19 -- identified with use of the immune system dysfunction literature -- are strong candidates to emerge eventually as CFs directly related to COVID-19. As discussed in the main text, many more CFs common to all these core literatures could be identified and validated. ID and IBD share many common risk/contributing factors, including behaviors and toxic exposures that impair immune function. A key component to immune system health is removal of those factors that contribute to immune system dysfunction in the first place. This requires a paradigm shift from traditional Western medicine, which often focuses on treatment, rather than prevention.

Role of MicroRNA in Inflammatory Bowel Disease: Clinical Evidence and the Development of Preclinical Animal Models

The dysregulation of microRNA (miRNA) is implicated in cancer, inflammation, cardiovascular disorders, drug resistance, and aging. While most researchers study miRNA's role as a biomarker, for example, to distinguish between various sub-forms or stages of a given disease of interest, research is also ongoing to utilize these small nucleic acids as therapeutics. An example of a common pleiotropic disease that could benefit from miRNA-based therapeutics is inflammatory bowel disease (IBD), which is characterized by chronic inflammation of the small and large intestines. Due to complex interactions between multiple factors in the etiology of IBD, development of therapies that effectively maintain remission for this disease is a significant challenge. In this review, we discuss the role of dysregulated miRNA expression in the context of clinical ulcerative colitis (UC) and Crohn's disease (CD)-the two main forms of IBD-and the various preclinical mouse models of IBD utilized to validate the therapeutic potential of targeting these miRNA. Additionally, we highlight advances in the development of genetically engineered animal models that recapitulate clinical miRNA expression and provide powerful preclinical models to assess the diagnostic and therapeutic promise of miRNA in IBD.

Detection of mutations in NOD2/CARD15 gene in Arab patients with Crohn's disease

BACKGROUND

Mutations in NOD2/CARD15 gene have been linked to an increased risk of Crohn's disease (CD). The objective of this study is to determine NOD2/CARD15 gene mutations, and their association with the risk of CD in Arabs in Kuwait.

METHODS

Four NOD2 gene mutations, including Pro268Ser (SNP5), Arg702Trp (SNP8), Gly908Arg (SNP12), and Leu1007FsinsC (SNP13) were examined in Arab CD patients (n = 103) and control subjects (n = 100). The genomic DNA was isolated and used in polymerase chain reaction (PCR) with four sets of specific primers. The PCR-amplified DNA fragments were sequenced and analyzed for the NOD2 mutations. Logistic regression was used to estimate the adjusted odds ratios (aOR) and 95% confidence intervals (CI).

RESULTS

Of the four genotyped variants, the Arg702Trp (SNP8) and Leu1007FsinsC (SNP13) variants were not informative in our study sample due to minor allele frequency of <1%. The Pro268Ser (SNP5) mutation was detected in 17 (16.5%) CD patients and 32 (32.0%) controls. The Gly908Arg (SNP12) mutation was observed in 24 (23.3%) patients and 10 (10.0%) controls. In the dominant genetic risk model (i.e. carrying at least one minor allele), CD patients compared to controls were less likely to carry either the "CT" or "TT" genotype of variant Pro268Ser (SNP5; aOR = 0.43, 95% CI: 0.22-0.84). In contrast, CD patients compared to controls were more likely to carry the homozygous for the minor allele or the heterozygous genotypes of variant Gly908Arg (SNP12; aOR = 2.67, 95% CI: 1.19-5.97).

CONCLUSIONS

In this Arab population, carrying at least one copy of the minor allele of Gly908Arg (SNP12) mutation in NOD2 gene was associated with increased susceptibility to CD, while having the heterozygous or homozygous for the minor allele genotype of the Pro268Ser (SNP5) mutation provided protection against CD. Mutations in Arg702Trp (SNP8) and Leu1007FsinsC (SNP13) were not detected in this sample of the Arab population in Kuwait.

Probiotic-Induced Tolerogenic Dendritic Cells: A Novel Therapy for Inflammatory Bowel Disease?

Inflammatory bowel diseases (IBDs) are immune-mediated, chronic relapsing diseases with a rising prevalence worldwide in both adult and pediatric populations. Treatment options for immune-mediated diseases, including IBDs, are traditional steroids, immunomodulators, and biologics, none of which are capable of inducing long-lasting remission in all patients. Dendritic cells (DCs) play a fundamental role in inducing tolerance and regulating T cells and their tolerogenic functions. Hence, modulation of intestinal mucosal immunity by DCs could provide a novel, additional tool for the treatment of IBD. Recent evidence indicates that probiotic bacteria might impact immunomodulation both in vitro and in vivo by regulating DCs’ maturation and producing tolerogenic DCs (tolDCs) which, in turn, might dampen inflammation. In this review, we will discuss this evidence and the mechanisms of action of probiotics and their metabolites in inducing tolDCs in IBDs and some conditions associated with them.

Role of Myeloid-derived suppressor cell (MDSC) in autoimmunity and its potential as a therapeutic target

Myeloid suppressor cells (MDSCs) are an important class of immune-regulating cells that can suppress T cell function. Most of our knowledge about the function of MDSC comes from studies of cancer models. Recent studies, however, have greatly contributed to the description of MDSC involvement in autoimmune diseases. They are known as a cell population that may negatively affect immune responses by regulating the function of CD4⁺ and CD8⁺ cells, which makes them an attractive target for autoimmune diseases therapy. However, many questions about MDSC activation, differentiation, and inhibitory functions remain unanswered. In this study, we have summarized the role of MDSCs in various autoimmune diseases, and the potential of targeting them for therapeutic benefits has been discussed.

Extracellular vesicles derived from gut microbiota in inflammatory bowel disease and colorectal cancer: new players?

The human gut microbiome encompasses inter alia, the myriad bacterial species that create the optimal host-microorganism balance essential for normal metabolic and immune function. Various lines of evidence suggest that dysregulation of the microbiota-host interaction is linked to pathologies such as inflammatory bowel disease (IBD) and colorectal cancer (CRC). Extracellular vesicles (EVs), found in virtually all body fluids and produced by both eukaryotic cells and bacteria are involved in cell-cell communication and crosstalk mechanisms, such as the immune response, barrier function and intestinal flora. This review highlights advancements in knowledge of the functional role that EVs may have in IBD and CRC, and discusses the possible use of EVs derived from intestinal microbiota in therapeutic strategies for treating these conditions.

Tyrosine kinase 2 and Janus kinase‒signal transducer and activator of transcription signaling and inhibition in plaque psoriasis

Plaque psoriasis is a common, chronic, systemic, immune-mediated inflammatory disease. The Janus kinase-signal transducer and activator of transcription pathway plays a major role in intracellular cytokine signaling in inflammatory processes involved in psoriasis. Although Janus kinase (JAK) 1-3 inhibitors have demonstrated efficacy in patients with moderate-to-severe psoriasis, safety concerns persist and no JAK inhibitor has received regulatory approval to treat psoriasis. Thus, an opportunity exists for novel oral therapies that are safe and efficacious in psoriasis. Tyrosine kinase 2 (TYK2) is a member of the JAK family of kinases and regulates signaling and functional responses downstream of the interleukin 12, interleukin 23, and type I interferon receptors. Deucravacitinib, which is an oral, selective inhibitor that binds to the regulatory domain of TYK2, and brepocitinib (PF-06700841) and PF-06826647, which are topical and oral TYK2 inhibitors, respectively, that bind to the active (adenosine triphosphate-binding) site in the catalytic domain, are in development for psoriasis. Selective, allosteric inhibition of TYK2 signaling may reduce the potential for toxicities associated with pan-JAK inhibitors. This article reviews Janus kinase-signal transducer and activator of transcription and TYK2 signaling and the efficacy and safety of JAK inhibitors in psoriasis to date, focusing specifically on TYK2 inhibitors.

Cytokine profile in patients with chronic non-bacterial osteomyelitis, juvenile idiopathic arthritis, and insulin-dependent diabetes mellitus

OBJECTIVES

Our study aimed to evaluate the cytokine levels in pediatric chronic non-bacterial osteomyelitis (CNO) patients and compare these with other immune-mediated diseases and healthy controls.

METHODS

In this prospective study, we included 42 children with CNO, 28 patients with non-systemic juvenile idiopathic arthritis (JIA), 17 children with insulin-dependent diabetes mellitus (IDDM), and 30 healthy age-matched controls. In each of the CNO patients and comparison groups, the levels of 14-3-3-η protein, S100A8/A9 protein, interleukin-4 (IL-4), interleukin-17 (IL-17), interleukin-18 (IL-18), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) were measured by ELISA assay.

RESULTS

All studied cytokines in the CNO patients were significantly higher than controls, and IDDM, 14-3-3-η protein, IL-18, IL-4, IL-17, IL-1β, and TNF-α were less than in JIA patients. In the discriminant analysis, ESR, 14-3-3 protein, S100A8/A9, IL-18, IL-4, and TNF-α can discriminate CNO from JIA, and 14-3-3 protein, S100A8/A9, IL-18, IL-17, IL-4, and TNF-α can distinguish CNO from other diseases and HC.

CONCLUSION

The increased level of pro-inflammatory cytokines confirms the role of monocyte-driven inflammation in CNO patients. Cytokines may prove valuable as biomarkers and potential therapeutic targets for CNO.

T helper cell immunity in pregnancy and influence on autoimmune disease progression

Pregnancy presents the maternal immune system with a unique immunological challenge since it has to defend against pathogens while tolerating paternal allo-antigens expressed by fetal tissues. T helper (Th) cells play a central role in modulating immune responses and recent advances have defined distinct contributions of various Th cell subsets throughout each phase of human pregnancy, while dysregulation in Th responses show association with multiple obstetrical complications. In addition to localized decidual mechanisms, modulation of Th cell immunity during gestation is mediated largely by oscillations in sex hormone concentrations. Aberrant Th cell responses also underlie several autoimmune disorders while pregnancy-induced changes in the balance of Th cell immunity has been shown to exert favorable outcomes in the progression Th1 and Th17 driven autoimmune conditions only to be followed by post-partal exacerbations in disease.

Preclinical Development of FA5, a Novel AMP-Activated Protein Kinase (AMPK) Activator as an Innovative Drug for the Management of Bowel Inflammation

Acadesine (ACA), a pharmacological activator of AMP-activated protein kinase (AMPK), showed a promising beneficial effect in a mouse model of colitis, indicating this drug as an alternative tool to manage IBDs. However, ACA displays some pharmacodynamic limitations precluding its therapeutical applications. Our study was aimed at evaluating the in vitro and in vivo effects of FA-5 (a novel direct AMPK activator synthesized in our laboratories) in an experimental model of colitis in rats. A set of experiments evaluated the ability of FA5 to activate AMPK and to compare the efficacy of FA5 with ACA in an experimental model of colitis. The effects of FA-5, ACA, or dexamethasone were tested in rats with 2,4-dinitrobenzenesulfonic acid (DNBS)-induced colitis to assess systemic and tissue inflammatory parameters. In in vitro experiments, FA5 induced phosphorylation, and thus the activation, of AMPK, contextually to the activation of SIRT-1. In vivo, FA5 counteracted the increase in spleen weight, improved the colon length, ameliorated macroscopic damage score, and reduced TNF and MDA tissue levels in DNBS-treated rats. Of note, FA-5 displayed an increased anti-inflammatory efficacy as compared with ACA. The novel AMPK activator FA-5 displays an improved anti-inflammatory efficacy representing a promising pharmacological tool against bowel inflammation.

An update on the role of anti-IL-12/IL23 agents in the management of inflammatory bowel disease

INTRODUCTION

The aim of treatment in inflammatory bowel disease (IBD) is to control symptoms and suppress gut inflammation with minimal systemic side effects. A large proportion of patients are either primary non-responders or lose response to currently licensed therapies. The development of monoclonal antibodies, blocking interleukin (IL)-12 and IL-23 pathways are a promising therapeutic advance. We review the data on IL12/23 inhibitors and emerging data on IL-23 inhibition in IBD treatment.

SOURCES OF DATA

This review is based on data published in peer-reviewed journals and clinical trials registry.

AREAS OF AGREEMENT

Ustekinumab is currently approved for managing corticosteroid and biologic refractory IBD patients with a favourable safety profile.

AREAS OF CONTROVERSY

Despite a growing therapeutic armamentarium and convergence on the role of biological therapies in patients with greater disease severity, there remains considerable uncertainty with selection and positioning of treatment.

GROWING POINTS

Efficacy data from clinical trials and a growing body of real-world data have established a role for IL12/23 inhibitor Ustekinumab in IBD. There is resurgent interest in IL-23 specificity and the potential for incremental benefit. The potential for IL-22 to act as a biomarker for IL-23 inhibitors has exciting implications for personalized medicine.

AREAS TIMELY FOR DEVELOPING RESEARCH

Head-to-head trials exploring efficacy and combination with other biologics with the potential for synergistic benefit are under investigation. Results of phase 3 trials with IL-23 inhibitors incorporating clinical, biochemical and endoscopic parameters and also exploring biomarkers as predictors of response are urgently needed.

Exploring the Mechanism of Berberine Intervention in Ulcerative Colitis from the Perspective of Inflammation and Immunity Based on Systemic Pharmacology

Background

Ulcerative colitis (UC) is a chronic nonspecific inflammatory disease of the colon and rectum. Recent studies found that berberine had effects on inflammatory diseases and immune diseases.

Methods

The PharmMapper database was used to predict the berberine potential target and GeneCards database and OMIM database were utilized to collect UC genes. The Cytoscape software was used to construct and analyze the networks and DAVID was utilized to perform enrichment analysis. Then, animal experiments were performed to validate the prediction results. The experimental rats were randomly divided into normal group (control group), model group, and berberine group. The general condition, body weight, gross morphology of colon tissue, and colonic mucosal damage index (CMDI) score were observed. The pathological changes of colon tissue were observed by H&E staining. The levels of serum interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-4 were detected by ELISA. The expressions of IL-1β, TNF-α, and IL-4 protein in colon tissue were detected by immunohistochemistry.

Results

A total of 211 Berberine's potential targets and 210 UC genes were obtained. The enrichment analysis showed that berberine may regulate inflammation, inflammatory cytokines, and their mediated inflammation signal pathways such as inflammatory bowel disease (IBD), rheumatoid arthritis, cytokine-cytokine receptor interaction, TNF, T cell receptor, Toll-like receptor, and JAK/STAT signaling pathway. Compared with the model group, the body mass of rats in the berberine group was significantly increased (P < 0.05); the general morphology and pathological changes of colon tissue were significantly improved; CMDI score, serum and colon tissue IL-1β, TNF-α content, and protein expression were decreased significantly (P < 0.05); and IL-4 content and protein expression increased significantly (P < 0.05).

Conclusion

Berberine can interfere with UC through related biological processes and signal pathways related to inflammation and immunity. In-depth exploration of the mechanism of berberine in the treatment of UC will provide a basis for clinical application.

Long Non-coding RNA MEG3 Alleviated Ulcerative Colitis Through Upregulating miR-98-5p-Sponged IL-10

Ulcerative colitis (UC) is a refractory chronic colitis disease with the particularly complex cause. Recently, long noncoding RNAs (lncRNAs) have been reported to be related to the development of UC. LncRNA MEG3 has been proved to play an anti-inflammatory role in a variety of inflammatory diseases, which share similar pathogenesis with UC, indicating the potential involvement of lncRNA MEG3 in UC. This study aims to investigate the functional role and underlying mechanism of lncRNA MEG3 in UC. Gradient concentration of H2O2 (0, 20, 50, 100, and 200 μM) was used to induce Caco-2 damage models in vitro. Cell viability was detected by cell counting kit-8 (CCK-8) assay. LncRNA MEG3, miR-98-5p, and IL-10 levels in H2O2-treated Caco-2 cells were assessed by performing real-time quantitative polymerase chain reaction (RT-qPCR). Moreover, the binding relationship between lncRNA MEG3 and miR-98-5p, as well as the binding relationship between miR-98-5p and IL-10, was validated using dual-luciferase reporter assay. 2, 4, 6-Trinitrobenzenesulfonic acid solution (TNBS) was applied to induce ulcerative colitis in young rats. The body weight, disease activity index (DAI), length and weight of the colons, pathological scores of UC rats, reactive oxygen species (ROS), and inflammatory cytokines were determined to evaluate the effects of lncRNA MEG3 on the progression of UC. Besides, hematoxylin-eosin (HE) staining was exploited to observe histological changes of UC rat colons. In addition, western blotting analysis was also performed to evaluate the apoptosis and pyroptosis-related protein levels. Moreover, lncRNA MEG3, miR-98-5p, and IL-10 levels in UC rat colons were further assessed by RT-qPCR. Meanwhile, IL-10 expression was determined using immunohistochemistry. LncRNA MEG3 and IL-10 levels were distinctly decreased while miR-98-5p was increased in Caco-2 damage models and UC rats. Bioinformatics analysis predicted the binding sites of lncRNA MEG3 to miR-98-5p and miR-98-5p to IL-10. Besides, dual-luciferase reporter assay validated the negative correlation between lncRNA MEG3 and miR-98-5p, miR-98-5p, and IL-10. Overexpressed lncRNA MEG3 reduced. DAI scores and colon weight/length ratio improved UC ulceration. In addition, upregulation of lncRNA MEG3 relieved oxidative stress, inflammatory response, apoptosis, and pyroptosis of UC rat colons. LncRNA MEG3 overexpression alleviates the serve ulceration of UC rat colons by upregulating IL-10 expression via sponging miR-98-5p. To sum up, this study reveals the protective role of lncRNA MEG3 in the development of UC and may provide potential therapeutic targets for UC.

Molecular Characterization and Seroprevalence of Hepatitis E Virus in Inflammatory Bowel Disease Patients and Solid Organ Transplant Recipients

Seroprevalence rates and molecular characterization of hepatitis E virus (HEV) prevalent in the Lithuanian human population has not yet been evaluated. Immunosuppressed individuals have been recognized as a risk group for chronic hepatitis due to HEV genotype 3 (HEV-3) infections. The objectives of the present study were to determine prevalence rates of anti-HEV antibodies among inflammatory bowel disease (IBD) patients and solid organ transplant (SOT) recipients, to isolate and characterize HEV strain present in the Lithuanian human population, and to investigate its capacity to infect non-human primate (MARC-145 and Vero), swine (PK-15) and murine (Neuro-2a) cells in vitro. In the present study, the significant difference of anti-HEV IgG prevalence between healthy (3.0% (95% CI 0-6.3)) and immunosuppressed individuals (12.0% [95% CI 8.1-15.9]) was described. Moreover, our findings showed that anti-HEV IgG seropositivity can be significantly predicted by increasing age (OR = 1.032, p < 0.01), diagnosis of IBD (OR = 4.541, p < 0.01) and reception of SOT (OR = 4.042, <0.05). Locally isolated HEV strain clustered within genotype 3i subtype of genotype 3 and was capable of infecting MARC-145 cells. This study demonstrates higher HEV seroprevalence in the risk group compared to healthy control individuals without confidence interval overlap. The high level of genetic homology between human and animal strains in Lithuania and the capacity of locally isolated strains to infect cells of non-human origin suggests its potential for zoonotic transmission.

Dapsone Ameliorates Colitis through TLR4/NF-kB Pathway in TNBS Induced Colitis Model in Rat

BACKGROUND

Crohn's disease (CD), a type of inflammatory bowel disease (IBD), emerges with severe gastrointestinal (GI) tract inflammation, sometimes known as hostile abdomen. Conventional treatment of CD has several limitations such as insufficient response to treatment, and intolerable side effects of drugs. In addition, the high cost of biologic drugs prevents patients from continuing their treatment. Dapsone showed vigorous anti-inflammatory effects on the skin diseases, lung diseases and inflammatory diseases of the nervous system. Hence, we decided to investigate the effect of dapsone on animal model of CD.

METHODS

In this study, colitis was induced by instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS) 100 mg/kg. Rats were treated with daily gavage of dapsone (10, 12.5 and 20 mg/kg). Seven days after induction of colitis, specimens were collected for pathological and molecular assessments.

RESULTS

Dapsone (12.5 and 20 mg/kg) preserved the histologic architecture of the colon and prevented crypts irregularity. Additionally, it decreased tissue edema and hindered inflammatory cells infiltration. Besides, all doses of dapsone decreased tissue concentration of tumor necrosis factor α (TNF-α) and interferon γ (INFγ). Western blot revealed that dapsone could attenuate inflammation via downregulation of toll-like receptor 4 (TLR4) and dephosphorylation of nuclear factor kB (NF-kB).

CONCLUSION

Based on these findings, dapsone attenuates inflammation and decreases TNF-α and INF-γ in animal model of CD. It acts through TLR4/NF-kB pathway to exert these effects.