Distinct cytokine patterns identified from multiplex profiles of murine DSS and TNBS-induced colitis

IFN-γ stimulates Paneth cell secretion through necroptosis mTORC1 dependent

Immune mediators affect multiple biological functions of intestinal epithelial cells (IECs) and, like Paneth and Paneth-like cells, play an important role in intestinal epithelial homeostasis. IFN-γ a prototypical proinflammatory cytokine disrupts intestinal epithelial homeostasis. However, the mechanism underlying the process remains unknown. In this study, using in vivo and in vitro models we demonstrate that IFN-γ is spontaneously secreted in the small intestine. Furthermore, we observed that this cytokine stimulates mitochondrial activity, ROS production, and Paneth and Paneth-like cell secretion. Paneth and Paneth-like secretion downstream of IFN-γ, as identified here, is mTORC1 and necroptosis-dependent. Thus, our findings revealed that the pleiotropic function of IFN-γ also includes the regulation of Paneth cell function in the homeostatic gut.

Repurposing disulfiram with CuET nanocrystals: Enhancing anti-pyroptotic effect through NLRP3 inflammasome inhibition for treating inflammatory bowel diseases

Drug repurposing offers a valuable strategy for identifying new therapeutic applications for existing drugs. Recently, disulfiram (DSF), a drug primarily used for alcohol addiction treatment, has emerged as a potential treatment for inflammatory diseases by inhibiting pyroptosis, a form of programmed cell death. The therapeutic activity of DSF can be further enhanced by the presence of Cu2+, although the underlying mechanism of this enhancement remains unclear. In this study, we investigated the mechanistic basis of Cu2+-induced enhancement and discovered that it is attributed to the formation of a novel copper ethylthiocarbamate (CuET) complex. CuET exhibited significantly stronger anti-pyroptotic activity compared to DSF and employed a distinct mechanism of action. However, despite its potent activity, CuET suffered from poor solubility and limited permeability, as revealed by our druggability studies. To overcome these intrinsic limitations, we developed a scalable method to prepare CuET nanocrystals (CuET NCs) using a metal coordination-driven self-assembly approach. Pharmacokinetic studies demonstrated that CuET NCs exhibited a 6-fold improvement in bioavailability. Notably, CuET NCs exhibited high biodistribution in the intestine, suggesting their potential application for the treatment of inflammatory bowel diseases (IBDs). To evaluate their therapeutic efficacy in vivo, we employed a murine model of DSS-induced colitis and observed that CuET NCs effectively attenuated inflammation and ameliorated colitis symptoms. Our findings highlight the discovery of CuET as a potent anti-pyroptotic agent, and the development of CuET NCs represents a novel approach to enhance the druggability of CuET.

Exploring the therapeutic potential of Anastatica hierochuntica essential oil in DSS-induced colitis

The aim of this investigation was to explore the protective impacts and mechanisms of Anastatica hierochuntica essential oil (EOAH) against dextran sulfate sodium (DSS)-induced experimental colitis in mice. EOAH demonstrated a reduction in DSS-induced body weight decline, disease activity index (DAI), colon length reduction, colonic tissue damage, and myeloperoxidase (MPO) activity. The essential oil significantly mitigated the production of pro-inflammatory agents including TNF-α, IL-1β, and IL-12. Further analysis revealed that EOAH's anti-inflammatory effects involved the regulation of NF-κB and PPARγ pathways, as well as the inhibition of NLRP3 activation in colitis mice. Notably, EOAH treatment elevated the levels of beneficial commensal bacteria such as Lactobacillus and Bifidobacteria, while reducing Escherichia coli levels in the mice's feces. In addition, EOAH restored the expression of occludin and ZO-1 proteins in colonic tissues affected by ulcerative colitis (UC). These findings indicate that supplementing with EOAH might offer a novel therapeutic approach for UC prevention.

Targeting Inflammation and Oxidative Stress to Improve Outcomes in a TNBS Murine Crohn's Colitis Model

Inflammation and oxidative stress are implicated in the pathogenesis of Crohn's disease. Cerium oxide nanoparticle (CNP) conjugated to microRNA 146a (miR146a) (CNP-miR146a) is a novel compound with anti-inflammatory and antioxidative properties. We hypothesized that local administration of CNP-miR146a would improve colitis in a 2,4,6-Trinitrobenzenesulfonic acid (TNBS) mouse model for Crohn's disease by decreasing colonic inflammation. Balb/c mice were instilled with TNBS enemas to induce colitis. Two days later, the mice received cellulose gel enema, cellulose gel with CNP-miR146a enema, or no treatment. Control mice received initial enemas of 50% ethanol and PBS enemas on day two. The mice were monitored daily for weight loss and clinical disease activity. The mice were euthanized on days two or five to evaluate their miR146a expression, inflammation on histology, and colonic IL-6 and TNF gene expressions and protein concentrations. CNP-miR146a enema successfully increased colonic miR146a expression at 12 h following delivery. At the end of five days from TNBS instillation, the mice treated with CNP-miR146a demonstrated reduced weight loss, improved inflammation scores on histology, and reduced gene expressions and protein concentrations of IL-6 and TNF. The local delivery of CNP-miR146a in a TNBS mouse model of acute Crohn's colitis dramatically decreased inflammatory signaling, resulting in improved clinical disease.

Resatorvid (TAK-242) Ameliorates Ulcerative Colitis by Modulating Macrophage Polarization and T Helper Cell Balance via TLR4/JAK2/STAT3 Signaling Pathway

Resatorvid (TAK-242), a specific inhibitor of Toll-like receptor-4 (TLR4), has attracted attention for its anti-inflammatory properties. Despite this, few studies have evaluated its effects on ulcerative colitis (UC). This study aimed to investigate the effects of TAK-242 on macrophage polarization and T helper cell balance and the mechanism by which it alleviates UC. Our findings indicated that TLR4 expression was elevated in patients with UC, a mouse model of UC, and HT29 cells undergoing an inflammatory response. TAK‑242 treatment reduced apoptosis in TNF-α and LPS-stimulated HT29 cells and alleviated symptoms of dextran sulfate sodium (DSS)‑induced colitis in vivo. TAK‑242 downregulated TLR4 expression and decreased the secretion of pro-inflammatory cytokines TNF-α, IL-6, and IL-1β while enhancing IL-10 production. TAK-242 also reduced M1 macrophage polarization and diminished Th1 and Th17 cell infiltration while increasing Th2 cell infiltration and M2 macrophage polarization both in vitro and in vivo. Mechanistically, TAK-242 inhibited the JAK2/STAT3 signaling pathway, an important regulator of macrophage polarization and T helper cell balance. Furthermore, the in vivo and in vitro effects of TAK-242 were partially negated by the administration of the JAK2/STAT3 antagonist AG490, suggesting that TAK-242 inhibits the JAK2/STAT3 pathway to exert its biological activities. Taken together, this study underscores TAK-242 as a promising anti-UC agent, functioning by modulating macrophage polarization and T helper cell balance via the TLR4/JAK2/STAT3 signaling pathway.

Arbutin alleviates intestinal colitis by regulating neutrophil extracellular traps formation and microbiota composition

BACKGROUND

Ulcerative colitis (UC) is a chronic recurrent intestinal disease lacking effective treatments. β-arbutin, a glycoside extracted from the Arctostaphylos uva-ursi leaves, that can regulate many pathological processes. However, the effects of β-arbutin on UC remain unknown.

PURPOSE

In this study, we investigated the role of β-arbutin in relieving colitis and explored its potential mechanisms in a mouse model of dextran sulfate sodium (DSS)-induced colitis.

METHODS

In C75BL/6 J mice, DSS was used to induce colitis and concomitantly β-arbutin (50 and 100 mg/kg) was taken orally to evaluate its curative effect by evaluating disease activity index (DAI) score, colon length and histopathology. Alcian blue periodic acid schiff (AB-PAS) staining, immunohistochemistry (IHC), immunofluorescence (IF) and TdT-mediated dUTP Nick-End Labeling (Tunel) staining were used to assess intestinal barrier function. Flow cytometry, double-IF and western blotting (WB) were performed to verify the regulatory mechanism of β-arbutin on neutrophil extracellular traps (NETs) in vivo and in vitro. NETs depletion experiments were used to demonstrate the role of NETs in UC. Subsequently, the 16S rRNA gene sequencing was used to analyze the intestinal microflora of mouse.

RESULTS

Our results showed that β-arbutin can protect mice from DSS-induced colitis characterized by a lower DAI score and intestinal pathological damage. β-arbutin reduced inflammatory factors secretion, notably regulated neutrophil functions, and inhibited NETs formation in an ErK-dependent pathway, contributing to the resistance to colitis as demonstrated by in vivo and in vitro experiments. Meanwhile, remodeled the intestinal flora structure and increased the diversity and richness of intestinal microbiota, especially the abundance of probiotics and butyric acid-producing bacteria. It further promoted the protective effect in the resistance of colitis.

CONCLUSION

β-arbutin promoted the maintenance of intestinal homeostasis by inhibiting NETs formation, maintaining mucosal-barrier integrity, and shaping gut-microbiota composition, thereby alleviating DSS-induced colitis. This study provided a scientific basis for the rational use of β-arbutin in preventing colitis and other related diseases.

Ziziphus jujuba Miller Ethanol Extract Restores Disrupted Intestinal Barrier Function via Tight Junction Recovery and Reduces Inflammation

Inflammatory bowel disease (IBD) is a chronic inflammatory condition caused by the disruption of the intestinal barrier. The intestinal barrier is maintained by tight junctions (TJs), which sustain intestinal homeostasis and prevent pathogens from entering the microbiome and mucosal tissues. Ziziphus jujuba Miller (Z. jujuba) is a natural substance that has been used in traditional medicine as a therapy for a variety of diseases. However, in IBD, the efficacy of Z. jujuba is unknown. Therefore, we evaluated ZJB in Caco2 cells and a dextran sodium sulfate (DSS)-induced mouse model to demonstrate its efficacy in IBD. Z. jujuba extracts were prepared using 70% ethanol and were named ZJB. ZJB was found to be non-cytotoxic and to have excellent antioxidant effects. We confirmed its anti-inflammatory properties via the down-regulation of inflammatory factors, including inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). To evaluate the effects of ZJB on intestinal barrier function and TJ improvement, the trans-epithelial electrical resistance (TEER) and fluorescein isothiocyanate-dextran 4 kDa (FITC-Dextran 4) permeability were assessed. The TEER value increased by 61.389% and permeability decreased by 27.348% in the 200 μg/mL ZJB group compared with the 50 ng/mL IL-6 group after 24 h. Additionally, ZJB alleviated body weight loss, reduced the disease activity index (DAI) score, and induced colon shortening in 5% DSS-induced mice; inflammatory cytokines, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 were down-regulated in the serum. TJ proteins, such as Zonula occludens (ZO)-1 and occludin, were up-regulated by ZJB in an impaired Caco2 mouse model. Additionally, according to the liquid chromatography results, in tandem with mass spectrometry (LC-MS/MS) analysis, seven active ingredients were detected in ZJB. In conclusion, ZJB down-regulated inflammatory factors, protected intestinal barrier function, and increased TJ proteins. It is thus a safe, natural substance with the potential to be used as a therapeutic agent in IBD treatment.

Effect of Moringa oleifera leaf polysaccharide on the composition of intestinal microbiota in mice with dextran sulfate sodium-induced ulcerative colitis

Moringa oleifera (M. oleifera) is a natural plant that has excellent nutritional and medicinal potential. M. oleifera leaves (MOL) contain several bioactive compounds. The aim of this study was to evaluate the potential effect of MOL polysaccharide (MOLP) on intestinal flora in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mice. DSS-induced colitis was deemed to be a well-characterized experimental colitis model for investigating the protective effect of drugs on UC. In this study, we stimulated the experimental mice with DSS 4% for 7 days and prepared the high dose of MOLP (MOLP-H) in order to evaluate its effect on intestinal flora in DSS-induced UC mice, comparing three experimental groups, including the control, DSS model, and DSS + MOLP-H (100 mg/kg/day). At the end of the experiment, feces were collected, and the changes in intestinal flora in DSS-induced mice were analyzed based on 16S rDNA high throughput sequencing technology. The results showed that the Shannon, Simpson, and observed species indices of abundance decreased in the DSS group compared with the control group. However, the indices mentioned above were increased in the MOLP-H group. According to beta diversity analysis, the DSS group showed low bacterial diversity and the distance between the control and MOLP-H groups, respectively. In addition, compared with the control group, the relative abundance of Firmicutes in the DSS group decreased and the abundance of Helicobacter increased, while MOLP-H treatment improves intestinal health by enhancing the number of beneficial organisms, including Firmicutes, while reducing the number of pathogenic organisms, such as Helicobacter. In conclusion, these findings suggest that MOLP-H may be a viable prebiotic with health-promoting properties.

Unveiling Colitis: A Journey through the Dextran Sodium Sulfate-induced Model

Animal models of inflammatory bowel disease (IBD) are valuable tools for investigating the factors involved in IBD pathogenesis and evaluating new therapeutic options. The dextran sodium sulfate (DSS)-induced model of colitis is arguably the most widely used animal model for studying the pathogenesis of and potential treatments for ulcerative colitis (UC), which is a primary form of IBD. This model offers several advantages as a research tool: it is highly reproducible, relatively easy to generate and maintain, and mimics many critical features of human IBD. Recently, it has also been used to study the role of gut microbiota in the development and progression of IBD and to investigate the effects of other factors, such as diet and genetics, on colitis severity. However, although DSS-induced colitis is the most popular and flexible model for preclinical IBD research, it is not an exact replica of human colitis, and some results obtained from this model cannot be directly applied to humans. This review aims to comprehensively discuss different factors that may be involved in the pathogenesis of DSS-induced colitis and the issues that should be considered when using this model for translational purposes.

Engaging natural antibody responses for the treatment of inflammatory bowel disease via phosphorylcholine-presenting nanofibres

Inflammatory bowel disease lacks a long-lasting and broadly effective therapy. Here, by taking advantage of the anti-infection and anti-inflammatory properties of natural antibodies against the small-molecule epitope phosphorylcholine (PC), we show in multiple mouse models of colitis that immunization of the animals with self-assembling supramolecular peptide nanofibres bearing PC epitopes induced sustained levels of anti-PC antibodies that were both protective and therapeutic. The strength and type of immune responses elicited by the nanofibres could be controlled through the relative valency of PC epitopes and exogenous T-cell epitopes on the nanofibres and via the addition of the adjuvant CpG. The nanomaterial-assisted induction of the production of therapeutic antibodies may represent a durable therapy for inflammatory bowel disease.

Animal models of inflammatory bowel disease: category and evaluation indexes

Inflammatory bowel disease (IBD) research often relies on animal models to study the etiology, pathophysiology, and management of IBD. Among these models, rats and mice are frequently employed due to their practicality and genetic manipulability. However, for studies aiming to closely mimic human pathology, non-human primates such as monkeys and dogs offer valuable physiological parallels. Guinea pigs, while less commonly used, present unique advantages for investigating the intricate interplay between neurological and immunological factors in IBD. Additionally, New Zealand rabbits excel in endoscopic biopsy techniques, providing insights into mucosal inflammation and healing processes. Pigs, with their physiological similarities to humans, serve as ideal models for exploring the complex relationships between nutrition, metabolism, and immunity in IBD. Beyond mammals, non-mammalian organisms including zebrafish, Drosophila melanogaster, and nematodes offer specialized insights into specific aspects of IBD pathology, highlighting the diverse array of model systems available for advancing our understanding of this multifaceted disease. In this review, we conduct a thorough analysis of various animal models employed in IBD research, detailing their applications and essential experimental parameters. These include clinical observation, Disease Activity Index score, pathological assessment, intestinal barrier integrity, fibrosis, inflammatory markers, intestinal microbiome, and other critical parameters that are crucial for evaluating modeling success and drug efficacy in experimental mammalian studies. Overall, this review will serve as a valuable resource for researchers in the field of IBD, offering insights into the diverse array of animal models available and their respective applications in studying IBD.

Naringin Alleviates Intestinal Fibrosis by Inhibiting ER Stress-Induced PAR2 Activation

Fibrosis characterized by intestinal strictures is a common complication of Crohn's disease (CD), without specific antifibrotic drugs, which usually relies on surgical intervention. The transcription factor XBP1, a key component of endoplasmic reticulum (ER) stress, is required for degranulation of mast cells and linked to PAR2 activation and fibrosis. Many studies have confirmed that naringin (NAR) can inhibit ER stress and reduce organ fibrosis. We hypothesized that ER stress activated the PAR2-induced epithelial-mesenchymal transition process by stimulating mast cell degranulation to release tryptase and led to intestinal fibrosis in CD patients; NAR might play an antifibrotic role by inhibiting ER stress-induced PAR2 activation. We report that the expression levels of XBP1, mast cell tryptase, and PAR2 are upregulated in fibrotic strictures of CD patients. Molecular docking simulates the interaction of NAR and spliced XBP1. ER stress stimulates degranulation of mast cells to secrete tryptase, activates PAR2-induced epithelial-mesenchymal transition process, and promotes intestinal fibrosis in vitro and vivo experiments, which is inhibited by NAR. Moreover, F2rl1 (the coding gene of PAR2) deletion in intestinal epithelial cells decreases the antifibrotic effect of NAR. Hence, the ER stress-mast cell tryptase-PAR2 axis can promote intestinal fibrosis, and NAR administration can alleviate intestinal fibrosis by inhibiting ER stress-induced PAR2 activation.

A Novel Lactobacillus brevis Fermented with a Vegetable Substrate (AL0035) Counteracts TNBS-Induced Colitis by Modulating the Gut Microbiota Composition and Intestinal Barrier

Crohn's and ulcerative colitis are common conditions associated with inflammatory bowel disease as well as intestinal flora and epithelial barrier dysfunction. A novel fermented Lactobacillus brevis (AL0035) herein assayed in a trinitro benzene sulfonic acid (TNBS)-induced colitis mice model after oral administration significantly counteracted the body weight loss and improves the disease activity index and histological injury scores. AL0035 significantly decreased the mRNA and protein expression of different pro-inflammatory cytokines (TNFalpha, IL-1beta, IL-6, IL-12, IFN-gamma) and enhanced the expression of IL-10. In addition, the probiotic promoted the expression of tight junction proteins, such as ZO-1, keeping the intestinal mucosal barrier function to attenuate colitis symptoms in mice. Markers of inflammation cascade such as myeloperoxidase (MPO) and PPAR-gamma measured in the colon were also modified by AL0035 treatment. AL0035 was also able to reduce different lymphocyte markers' infiltration in the colon (GATA-3, T-Bet, NK1.1) and monocyte chemoattractant protein-1 (MCP-1/CCL2), a key chemokine involved in the migration and infiltration of monocytes/macrophages in the immunological surveillance of tissues and inflammation. In colonic microbiota profile analysis through 16S rRNA sequencing, AL0035 increased the microbial diversity depleted by TNBS administration and the relative abundance of the Lactobacillaceae and Lachnospiraceae families, whereas it decreased the abundance of Proteobacteria. Altogether, these data indicated that AL0035 could lower the severity of colitis induced by TNBS by regulating inflammatory cytokines, increasing the expression of tight junction proteins and modulating intestinal microbiota, thus preventing tissue damage induced by colitis.

LRRK2 G2019S Promotes Colon Cancer Potentially via LRRK2-GSDMD Axis-Mediated Gut Inflammation

Leucine-rich repeat kinase 2 (LRRK2) is a serine-threonine protein kinase belonging to the ROCO protein family. Within the kinase domain of LRRK2, a point mutation known as LRRK2 G2019S has emerged as the most prevalent variant associated with Parkinson's disease. Recent clinical studies have indicated that G2019S carriers have an elevated risk of cancers, including colon cancer. Despite this observation, the underlying mechanisms linking LRRK2 G2019S to colon cancer remain elusive. In this study, employing a colitis-associated cancer (CAC) model and LRRK2 G2019S knock-in (KI) mouse model, we demonstrate that LRRK2 G2019S promotes the pathogenesis of colon cancer, characterized by increased tumor number and size in KI mice. Furthermore, LRRK2 G2019S enhances intestinal epithelial cell proliferation and inflammation within the tumor microenvironment. Mechanistically, KI mice exhibit heightened susceptibility to DSS-induced colitis, with inhibition of LRRK2 kinase activity ameliorating colitis severity and CAC progression. Our investigation also reveals that LRRK2 G2019S promotes inflammasome activation and exacerbates gut epithelium necrosis in the colitis model. Notably, GSDMD inhibitors attenuate colitis in LRRK2 G2019S KI mice. Taken together, our findings offer experimental evidence indicating that the gain-of-kinase activity in LRRK2 promotes colorectal tumorigenesis, suggesting LRRK2 as a potential therapeutic target in colon cancer patients exhibiting hyper LRRK2 kinase activity.

An updated advancement of bifunctional IL-27 in inflammatory autoimmune diseases

Interleukin-27 (IL-27) is a member of the IL-12 family. The gene encoding IL-27 is located at chromosome 16p11. IL-27 is considered as a heterodimeric cytokine, which consists of Epstein-Barr virus (EBV)-induced gene 3 (Ebi3) and IL-27p28. Based on the function of IL-27, it binds to receptor IL-27rα or gp130 and then regulates downstream cascade. To date, findings show that the expression of IL-27 is abnormal in different inflammatory autoimmune diseases (including systemic lupus erythematosus, rheumatoid arthritis, Sjogren syndrome, Behcet's disease, inflammatory bowel disease, multiple sclerosis, systemic sclerosis, type 1 diabetes, Vogt-Koyanagi-Harada, and ankylosing spondylitis). Moreover, in vivo and in vitro studies demonstrated that IL-27 is significantly in3volved in the development of these diseases by regulating innate and adaptive immune responses, playing either an anti-inflammatory or a pro-inflammatory role. In this review, we comprehensively summarized information about IL-27 and autoimmunity based on available evidence. It is hoped that targeting IL-27 will hold great promise in the treatment of inflammatory autoimmune disorders in the future.

Perineuronal net in the extrinsic innervation of the distal colon of mice and its remodeling in ulcerative colitis

The perineuronal net (PNN) is a well-described highly specialized extracellular matrix structure found in the central nervous system. Thus far, no reports of its presence or connection to pathological processes have been described in the peripheral nervous system. Our study demonstrates the presence of a PNN in the spinal afferent innervation of the distal colon of mice and characterizes structural and morphological alterations induced in an ulcerative colitis (UC) model. C57Bl/6 mice were given 3% dextran sulfate sodium (DSS) to induce acute or chronic UC. L6/S1 dorsal root ganglia (DRG) were collected. PNNs were labeled using fluorescein-conjugated Wisteria Floribunda (WFA) l lectin, and calcitonin gene-related peptide (CGRP) immunofluorescence was used to detect DRG neurons. Most DRG cell bodies and their extensions toward peripheral nerves were found surrounded by the PNN-like structure (WFA+), labeling neurons' cytoplasm and the pericellular surfaces. The amount of WFA+ neuronal cell bodies was increased in both acute and chronic UC, and the PNN-like structure around cell bodies was thicker in UC groups. In conclusion, a PNN-like structure around DRG neuronal cell bodies was described and found modulated by UC, as changes in quantity, morphology, and expression profile of the PNN were detected, suggesting a potential role in sensory neuron peripheral sensitization, possibly modulating the pain profile of ulcerative colitis.

Dietary Cannabidiol Activates PKA/AMPK Signaling and Attenuates Chronic Inflammation and Leaky Gut in DSS-Induced Colitis Mice

SCOPE

Inflammatory bowel disease (IBD) is characterized by chronic inflammation in the gut, accompanied by impaired epithelial integrity, increased macrophage infiltration, and enhanced colon cancer risk.

METHODS AND RESULTS

Cannabidiol (CBD), a phytocannabinoid isolated from cannabis plants, is supplemented into mice diet, and its beneficial effects against dextran sulfate sodium (DSS)-induced experimental colitis is evaluated. Eight-week-old mice were fed a standard diet supplemented with or without CBD (200 mg kg-1 ) for 5 weeks. In the 4th week of dietary treatment, mice were subjected to 2.5% DSS induction for 7 days, followed by 7 days of recovery, to induce colitis. CBD supplementation reduced body weight loss, gross bleeding, fecal consistency, and disease activity index. In addition, CBD supplementation protected the colonic structure, promoted tissue recovery, and ameliorated macrophage infiltration in the colonic tissue, which was associated with the activation of cyclic AMP-protein kinase A, extracellular signal-regulated kinase ½, and AMP-activated protein kinase signaling pathways. CBD supplementation also suppressed NLRP3 inflammasome activation and related pro-inflammatory marker secretion. Consistently, CBD feeding reduced tight junction protein claudin2 and myosin light chain kinase in DSS-treated mice.

CONCLUSION

Dietary CBD protects against inflammation and colitis symptoms induced by DSS, providing an alternative approach to IBD management.

Effects of myeloperoxidase on inflammatory responses with hypoxia in Citrobacter rodentium-infectious mice

PURPOSE

Myeloperoxidase (MPO) has been identified as a mediator in various inflammatory diseases. Bacterial infection of the intestine and hypoxia can both lead to inflammatory responses, but the role of MPO in these phenomena remains unclear.

METHODS

By building the MPO-/- mice, we evaluated relevant inflammatory factors and tissue damage in mice with intestinal Citrobacter rodentium infection and hypoxia. The body weight and excreted microorganisms were monitored. Intestinal tissues were collected 7 days after bacterial infection under hypoxia to undergo haematoxylin-eosin staining and assess the degree of pathological damage. ELISA assays were performed to quantify the serum levels of TNF-α, IFN-γ, IL-6, and IL-1β inflammatory cytokines. PCR, WB, and IF assays were conducted to determine the expression of chemokines MCP1, MIP2, and KC in the colon and spleen.

RESULTS

The C. rodentium infection and hypoxia caused weight loss, intestinal colitis, and splenic inflammatory cells active proliferation in wild-type mice. MPO deficiency alleviated this phenomenon. MPO-/- mice also displayed a significant decline in bacteria clearing ability. The level of TNF-α in the serum and spleen was both lower in MPO-/- hypoxia C. rodentium-infected mice than that in wild-type mice. The chemokines expression levels of MIP2, KC, and MCP1 in the spleen and colon of each bacterial infected group were significantly increased (p < .05), while in hypoxia, the factors in the spleen and colon were decreased (p < .05). MPO deficiency was found to lower the levels of these chemokines compared with wild-type mice.

CONCLUSION

MPO plays an important role of the inflammatory responses in infectious enteritis and hypoxia in mice, and the loss of MPO may greatly reduce the body's inflammatory responses to fight diseases.

Non-Intoxicating Cannabinoids in Visceral Pain

Cannabis and cannabis products are becoming increasingly popular options for symptom management of inflammatory bowel diseases, particularly abdominal pain. While anecdotal and patient reports suggest efficacy of these compounds for these conditions, clinical research has shown mixed results. To date, clinical research has focused primarily on delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is a ligand of classical cannabinoid receptors (CBRs). CBD is one of a large group of nonintoxicating cannabinoids (niCBs) that mediate their effects on both CBRs and through non-CBR mechanisms of action. Because they are not psychotropic, there is increasing interest and availability of niCBs. The numerous niCBs show potential to rectify abnormal intestinal motility as well as have anti-inflammatory and analgesic effects. The effects of niCBs are frequently not mediated by CBRs, but rather through actions on other targets, including transient receptor potential channels and voltage-gated ion channels. Additionally, evidence suggests that niCBs can be combined to increase their potency through what is termed the entourage effect. This review examines the pre-clinical data available surrounding these niCBs in treatment of abdominal pain with a focus on non-CBR mechanisms.

Effects of polyphenolic maqui (Aristotelia chilensis) extract on the inhibition of NLRP3 inflammasome and activation of mast cells in a mouse model of Crohn's disease-like colitis

Introduction

Crohn's disease (CD) involves activation of mast cells (MC) and NF-кB in parallel with the PPAR-α/NLRP3 inflammasome/IL-1β pathway in the inflamed colon. Whether polyphenols from maqui (Aristotelia chilensis) represent a natural alternative treatment for CD is unclear. Therefore, we used an animal model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced CD-like colitis to investigate protective effects of maqui extract through monitoring NLRP3 inflammasome and MC activation in colon tissue.

Methods

Maqui extract was administered via orogastric route to mice after (post-Treatment group) or prior (pre-Treatment group) to TNBS-induction. Colon pathology was characterized by histoarchitectural imaging, disease activity index (DAI), and assessing NF-кB, p-NF-кB, PPAR-α/NLRP3 expression and IL-1β levels.

Results

Compared to mice treated with TNBS alone administration of anthocyanin-rich maqui extract improved the DAI, colon histoarchitecture and reduced both colon wet-weight and transmural inflammation. Induction with TNBS significantly increased colonic NLPR3 inflammasome activation, while co-treatment with maqui extract (either post- or pre-Treatment) significantly downregulated NLRP3, ASC and caspase-1 levels, which manifested as reduced colonic IL-1β levels. Supplemented maqui extract marginally diminished NF-кB activity in epithelial cells but reached statistical significance in immune cells (as judged by decreased NF-кB phosphorylation). PPAR-α signaling was largely unaffected by Maqui whereas MC infiltration into the colon mucosa and submucosa decreased and their level of degranulation was suppressed.

Conclusion

These outcomes show the post- and pre- Treatment effect of a polyphenolic extract rich in anthocyanins from maqui the acute phase of TNBS- induced CD-like colitis is linked to suppression of the NLRP3 inflammasome and reduced MC responses. These data indicate that maqui extract represents a potential nutraceutical for the treatment of inflammatory bowel disease (IBD).

Transient receptor potential melastatin 2 is involved in trinitrobenzene sulfonic acid-induced acute and chronic colitis-associated fibrosis progression in mice

Crohn's disease, a chronic and recurrent gastrointestinal disease, frequently causes intestinal fibrosis. Transient receptor potential melastatin 2 (TRPM2), a non-selective cation channel, is activated by reactive oxygen species. This study investigated the role of TRPM2 in acute colitis and chronic colitis-associated fibrosis progression. Acute colitis and chronic colitis-associated fibrosis were induced in TRPM2-deficient (TRPM2KO) and wild-type (WT) mice through single and repeated intrarectal injections of 2,4,6-trinitrobenzene sulfonic acid (TNBS). Bone marrow-derived macrophages (BMDMs) from WT and TRPM2KO mice were stimulated using H2O2. In WT mice, a single TNBS injection induced acute colitis with upregulated inflammatory cytokines/chemokines and Th1/Th17-related cytokines, while repeated TNBS injections induced chronic colitis-associated fibrosis with upregulation of fibrogenic factors and Th2-related cytokines. Acute colitis and chronic colitis-associated fibrosis with cytokines/chemokine upregulation and fibrogenic factors were considerably suppressed in TRPM2KO mice. Treating BMDMs with H2O2 increased cytokine/chemokine expression and JNK, ERK, and p38 phosphorylation; however, these responses were significantly less in TRPM2KO than in WT mice. These findings suggest that TRPM2 contributes to acute colitis progression via Th1/Th17-mediated immune responses. Furthermore, TRPM2 may be directly involved in colitis-associated fibrosis induction, likely due to the regulation of Th2/TGF-β1-mediated fibrogenesis in addition to a consequence of acute colitis progression.

The protease ADAM17 at the crossroads of disease: revisiting its significance in inflammation, cancer, and beyond

The protease A Disintegrin And Metalloproteinase 17 (ADAM17) plays a central role in the pathophysiology of several diseases. ADAM17 is involved in the cleavage and shedding of at least 80 known membrane-tethered proteins, which subsequently modulate several intracellular signaling pathways, and therefore alter cell behavior. Dysregulated expression and/or activation of ADAM17 has been linked to a wide range of autoimmune and inflammatory diseases, cancer, and cardiovascular disease. In this review, we provide an overview of the current state of knowledge from preclinical models and clinical data on the diverse pathophysiological roles of ADAM17, and discuss the mechanisms underlying ADAM17-mediated protein shedding and the potential therapeutic implications of targeting ADAM17 in these diseases.

Molecular action mechanisms of two novel and selective calcium release-activated calcium channel antagonists

The prototypical calcium release-activated calcium (CRAC) channel, composed of STIM1 and Orai1, is a sought-after drug target for treating autoimmune disorders. Herein, we identified two novel and selective CRAC channel inhibitors, the indole-like compound C63368 and pyrazole core-containing compound C79413, potently and reversibly inhibiting the CRAC channel with low micromolar IC50s and sparing various off-target ion channels. These two compounds did not inhibit STIM1 activation or its coupling with Orai1, nor did they affect the channel's calcium-dependent fast inactivation. Instead, they directly acted on the Orai1 protein, with the channel's pore geometry profoundly affecting their potencies. In vitro, C63368 and C79413 effectively inhibited Jurkat cell proliferation and cytokines production in human T lymphocytes. Intragastric administration of C63368 and C79413 to mice yielded great therapeutic benefits in psoriasis and colitis animal models of autoimmune disorders, reducing serum cytokines production and significantly relieving pathological symptoms. It's worth noting, that this study provided the first insight into the characterization and mechanistic investigation of an indole-like CRAC channel antagonist. Altogether, the identification of these two highly selective CRAC channel antagonists, coupled with the elucidation of their action mechanisms, not only provides valuable template molecules but also offers profound insights for drug development targeting the CRAC channel.

Red Cabbage Juice-Mediated Gut Microbiota Modulation Improves Intestinal Epithelial Homeostasis and Ameliorates Colitis

Gut microbiota plays a crucial role in inflammatory bowel diseases (IBD) and can potentially prevent IBD through microbial-derived metabolites, making it a promising therapeutic avenue. Recent evidence suggests that despite an unclear underlying mechanism, red cabbage juice (RCJ) alleviates Dextran Sodium Sulfate (DSS)-induced colitis in mice. Thus, the study aims to unravel the molecular mechanism by which RCJ modulates the gut microbiota to alleviate DSS-induced colitis in mice. Using C57BL/6J mice, we evaluated RCJ's protective role in DSS-induced colitis through two cycles of 3% DSS. Mice were daily gavaged with PBS or RCJ until the endpoint, and gut microbiota composition was analyzed via shotgun metagenomics. RCJ treatment significantly improved body weight (p ≤ 0.001), survival in mice (p < 0.001) and reduced disease activity index (DAI) scores. Further, RCJ improved colonic barrier integrity by enhancing the expression of protective colonic mucins (p < 0.001) and tight junction proteins (p ≤ 0.01) in RCJ + DSS-treated mice compared to the DSS group. Shotgun metagenomic analysis revealed an enrichment of short-chain fatty acids (SCFAs)-producing bacteria (p < 0.05), leading to increased Peroxisome Proliferator-Activated Receptor Gamma (PPAR-γ) activation (p ≤ 0.001). This, in turn, resulted in repression of the nuclear factor κB (NFκB) signaling pathway, causing decreased production of inflammatory cytokines and chemokines. Our study demonstrates colitis remission in a DSS-induced mouse model, showcasing RCJ as a potential modulator for gut microbiota and metabolites, with promising implications for IBD prevention and treatment.

Immortalized Canine Adipose-Derived Mesenchymal Stem Cells Maintain the Immunomodulatory Capacity of the Original Primary Cells

Mesenchymal stem cells (MSCs) are a promising cell source for stem cell therapy of intractable diseases in veterinary medicine, but donor-dependent cellular heterogeneity is an issue that influences therapeutic efficacy. Thus, we previously established immortalized cells that maintain the fundamental properties of primary cells, but functional evaluation had not been performed. Therefore, we evaluated the immunomodulatory capacity of the immortalized canine adipose-derived MSCs (cADSCs) in vitro and in vivo to investigate whether they maintain primary cell functions. C57BL/6J mice were treated with dextran sulfate sodium (DSS) to induce colitis, injected intraperitoneally with immortalized or primary cADSCs on day 2 of DSS treatment, and observed for 10 days. Administration of immortalized cADSCs improved body weight loss and the disease activity index (DAI) in DSS-induced colitic mice by shifting peritoneal macrophage polarity from the M1 to M2 phenotype, suppressing T helper (Th) 1/Th17 cell responses and inducing regulatory T (Treg) cells. They also inhibited the proliferation of mouse and canine T cells in vitro. These immunomodulatory effects were comparable with primary cells. These results highlight the feasibility of our immortalized cADSCs as a cell source for stem cell therapy with stable therapeutic efficacy because they maintain the immunomodulatory capacity of primary cells.

Therapeutic Effects of Zymomonas mobilis on Experimental DSS-Induced Colitis Mouse Model

Zymomonas mobilis, a Gram-negative bacteria observed in some popular beverages, is considered safe and has been studied for its potential therapeutic benefits. In this study, we explored its effects on the inflammatory process, tissue integrity, differential gene expression, and microbiota composition in an experimental dextran sulfate sodium (DSS)-induced colitis model in mice. As a result, Z. mobilis alleviated the symptoms caused by DSS administration, as indicated by reduced weight loss, disease activity index, a significant reduction in the colon weight/length ratio, and histopathological improvement. Also, Z. mobilis could restore the mucosal barrier as well as increase the expression of Muc3 and Ocln genes. An analysis of 16S rRNA sequences showed that Z. mobilis alters gut microbiota, increasing Akkermansia muciniphila abundance and decreasing Escherichia coli. Furthermore, Z. mobilis seems to be involved in potentiating a regulatory phenotype by inducing immunomodulatory genes like Tgfb, Il5, Il10, and Foxp3 and reducing the relative mRNA expression of proinflammatory cytokines TNF, Il6, and Il17. Our data suggest that Z. mobilis could alleviate disease progression and be considered a possible probiotic adjuvant for pathologies of the bowel.

Prophylactic Coloprotective Effect of Urtica dioica Leaves against Dextran Sulfate Sodium (DSS)-Induced Ulcerative Colitis in Rats

Background and Objectives: Urtica dioica, a source of bioactive functional compounds, provides nutritional and gastrointestinal therapeutic benefits. This study attempted to investigate the prophylactic coloprotective action of an aqueous extract of Urtica dioica (AEUD) on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC). Materials and Methods: Phenolic compounds, total sugar, and mineral levels were determined in AEUD. Then, AEUD at different doses (50, 100, and 200 mg/kg, BW, p.o.) and mesalazine (MESA) as a standard treatment (100 mg/kg, BW, p.o.) were given orally for 21 days. Acute colitis was induced by administering drinking water with 5% (w/v) DSS for 7 days. Body weight variation, fecal occult blood, and stool consistency were determined daily. The severity of colitis was graded according to colon length, disease activity index (DAI), histological evaluations, and biochemical alterations. Rats orally administered DSS regularly developed clinical and macroscopic signs of colitis. Results: Due to its richness in phenolic and flavonoid compounds (247.65 ± 2.69 mg EAG/g MS and 34.08 ± 0.53 mg EQt/g MS, respectively), AEUD markedly ameliorated DAI, ulcer scores, colon length shortening, colonic histopathological changes, and hematological and biochemical modifications. Taken together, AEUD treatment notably (p < 0.01) suppressed DSS-induced UC by reducing oxidative stress via lowering MDA/H2O2 production and stimulating the effect of enzyme antioxidants as well as attenuating inflammation by decreasing CRP levels by 79.5% between the DSS and DSS + AEUD-50 groups compared to the MESA group (75.6%). Conclusions: AEUD was sufficient to exert a coloprotective effect that might be influenced by its bioactive compounds' anti-inflammatory and antioxidant capabilities.

Altered peripheral taste function in a mouse model of inflammatory bowel disease

Increased sugar intake and taste dysfunction have been reported in patients with inflammatory bowel disease (IBD), a chronic disorder characterized by diarrhea, pain, weight loss and fatigue. It was previously unknown whether taste function changes in mouse models of IBD. Mice consumed dextran sodium sulfate (DSS) during three 7-day cycles to induce chronic colitis. DSS-treated mice displayed signs of disease, including significant weight loss, diarrhea, loss of colon architecture, and inflammation of the colon. After the last DSS cycle we assessed taste function by recording electrophysiological responses from the chorda tympani (CT) nerve, which transmits activity from lingual taste buds to the brain. DSS treatment significantly reduced neural taste responses to natural and artificial sweeteners. Responses to carbohydrate, salt, sour or bitter tastants were unaffected in mice with colitis, but umami responses were modestly elevated. DSS treatment modulated the expression of receptor subunits that transduce sweet and umami stimuli in oral taste buds as a substrate for functional changes. Dysregulated systemic cytokine responses or dysbiosis that occurs during chronic colitis may be upstream from changes in oral taste buds. We demonstrate for the first time that colitis alters taste input to the brain, which could exacerbate malnutrition in IBD patients.

Celery soluble dietary fiber antagonizes flavonoids ameliorative effect on dextran-sodium-sulfate-induced colitis in mice

INTRODUCTION

Dietary fiber and flavonoids are promising drugs reported in the treatment of inflammatory bowel disease (IBD). However, it is unclear the interaction between dietary fiber and flavonoids in gut health.

OBJECTIVE

The therapeutic effect of celery, kale, and red chicory powders on colitis mice using non-group feeding cages was investigated. Further, the efficacy of whole celery, celery soluble dietary fiber (CSDF), celery insoluble dietary fiber (CIDF), celery flavonoids (CF), CSDF + CF and CIDF + CF in IBD mice model was assessed to dissect protective effect to attribute to which component(s) in such complex matrix.

METHODS

3% Dextran sulfate sodium salt (DSS) was used to induce mice colitis model. Multiple molecular biological methods were employed to evaluate the severity of mice colitis and the gut microbial composition of mice.

RESULTS

Administration of kale and red chicory significantly restored body weight, DAI score, and colon length in colonic mice, and celery showed the weakest effects. Administration of either CSDF or CF markedly improved the histological damage, increased colonic mucus expression, and reduced colonic MPO/iNOS activities, and IL-6/IL-1β levels. However, CSDF + CF showed weaker improvement than CF or SDF in most physical and biochemical signs. Furthermore, CSDF and CF decreased intestinal g_Escherichia-Shihella and g_Clostridium_sensu_stricto_1 induced by DSS administration. Interestingly, celery flavonoid promoted g_Akkermansia proliferation both in vivo and in vitro, and which can be inhibited by CSDF.

CONCLUSIONS

This study revealed for the first time that CSDF can suppress the protective effect of CF on intestinal health by inhibiting g_Akkermansia, and clarified that the decreased efficacy of celery whole food on colitis was mediated by an antagonism between CSDF and CF. Moreover, this study presents for the first time that interaction between soluble dietary fiber and flavonoids in vivo can ameliorate the efficacy of dietary fiber or flavonoids when administered alone suggestive for an antagonistic effect.

Central regulation of stress-evoked peripheral immune responses

Stress-linked psychiatric disorders, including anxiety and major depressive disorder, are associated with systemic inflammation. Recent studies have reported stress-induced alterations in haematopoiesis that result in monocytosis, neutrophilia, lymphocytopenia and, consequently, in the upregulation of pro-inflammatory processes in immunologically relevant peripheral tissues. There is now evidence that this peripheral inflammation contributes to the development of psychiatric symptoms as well as to common co-morbidities of psychiatric disorders such as metabolic syndrome and immunosuppression. Here, we review the specific brain and spinal regions, and the neuronal populations within them, that respond to stress and transmit signals to peripheral tissues via the autonomic nervous system or neuroendocrine pathways to influence immunological function. We comprehensively summarize studies that have employed retrograde tracing to define neurocircuits linking the brain to the bone marrow, spleen, gut, adipose tissue and liver. Moreover, we highlight studies that have used chemogenetic or optogenetic manipulation or intracerebroventricular administration of peptide hormones to control somatic immune responses. Collectively, this growing body of literature illustrates potential mechanisms through which stress signals are conveyed from the CNS to immune cells to regulate stress-relevant behaviours and comorbid pathophysiology.

Altered peripheral taste function in a mouse model of inflammatory bowel disease

Increased sugar intake and taste dysfunction have been reported in patients with inflammatory bowel disease (IBD), a chronic disorder characterized by diarrhea, pain, weight loss and fatigue. It was previously unknown whether taste function changes in mouse models of IBD. Mice consumed dextran sodium sulfate (DSS) during three 7-day cycles to induce chronic colitis. DSS-treated mice displayed signs of disease, including significant weight loss, diarrhea, loss of colon architecture, and inflammation of the colon. After the last DSS cycle we assessed taste function by recording electrophysiological responses from the chorda tympani (CT) nerve, which transmits activity from lingual taste buds to the brain. DSS treatment significantly reduced neural taste responses to natural and artificial sweeteners. Responses to carbohydrate, salt, sour or bitter tastants were unaffected in mice with colitis, but umami responses were modestly elevated. DSS treatment modulated the expression of receptor subunits that transduce sweet and umami stimuli in oral taste buds as a substrate for functional changes. Dysregulated systemic cytokine responses, or dysbiosis that occurs during chronic colitis may be upstream from changes in oral taste buds. We demonstrate for the first time that colitis alters taste input to the brain, which could exacerbate malnutrition in IBD patients.

Taurodeoxycholate ameliorates DSS-induced colitis in mice

BACKGROUND

Inflammatory bowel disease (IBD) is typically managed using medications such as 5-aminosalicylic acid (5-ASA), glucocorticoids, anti-TNFα Ab, or anti-IL-12/23 Ab. However, some patients do not respond well to these treatments or frequently experience relapses. Therefore, alternative therapeutic options are needed. Since the activation of the inflammasome is crucial to the pathogenesis of IBD, inhibiting the inflammasome may be beneficial for patients.

MATERIALS AND METHODS

We tested the efficacy of taurodeoxycholate (TDCA), which is a known G-protein coupled receptor 19 (GPCR19) agonist, in a mouse colitis model induced by dextran sodium sulfate (DSS).

RESULTS

In the mouse colitis model, TDCA prevented loss of body weight, shortening of the colon, production of pro-inflammatory cytokines, infiltration of pro-inflammatory cells, and mucosal ulceration in the colon. In vitro, TDCA inhibited the activation of NF-κB in bone marrow-derived macrophages (BMDMs) by activating the cAMP-PKA axis. TDCA downregulated the expression of purinergic receptor P2X7 (P2X7R) and enhanced the colocalization of P2X7R with GPCR19, and inhibited the Ca2+ mobilization of BMDMs when stimulated with ATP or BzATP, which plays a pivotal role in activating the NLRP3 inflammasome (N3I) via P2X7R. TDCA inhibited the oligomerization of NLRP3-ASC and downregulated the expression of NLRP3 and ASC, as well as suppressed the maturation of pro-caspase-1 and pro-IL-1β. TDCA also increased the percentage of M2 macrophages while decreasing the number of M1 macrophages, Th1, Th2, and Th17 cells in the colon.

CONCLUSION

TDCA ameliorated DSS-induced colitis in mice, possibly by inhibiting both the priming phase (via the GPCR19-cAMP-PKA-NF-κB axis) and the activation phase (via the GPCR19-P2X7R-NLRP3-Caspase 1-IL-1β axis) of N3I signaling.

Red cabbage juice-mediated gut microbiota modulation improves intestinal epithelial homeostasis and ameliorates colitis

Gut microbiota plays a crucial role in inflammatory bowel disease (IBD) and has therapeutic benefits. Thus, targeting the gut microbiota is a promising therapeutic approach for IBD treatment. We recently found that red cabbage juice (RCJ) ameliorates dextran sulfate sodium (DSS)-induced colitis in mice. However, the underlying mechanisms remain unknown. The current study investigated the modulation of gut microbiota in response to treatment with RCJ to ameliorate the DSS colitis. The initial results demonstrated that mice treated with DSS + RCJ showed increased body weight and decreased diarrhea and blood in feces compared to the DSS alone group. RCJ ameliorated colitis by regulating the intestinal barrier function by reducing the number of apoptotic cells, improving colonic protective mucin, and increasing tight junction protein in RCJ + DSS groups compared to the DSS group. Short-gun metagenomic analysis revealed significant enrichment of short-chain fatty acid (SCFAs)-producing bacteria (Butyrivibrio, Ruminococcaceae, Acetatifactor muris, Rosburia Sp. CAG:303 , Dorea Sp. 5-2) increased PPAR-© activation, leading to repression of the nuclear factor κB (NFκB) signaling pathway, thus decreasing the production of crucial inflammatory cytokines and chemokines in the RCJ + DSS groups compared to the DSS group. Pathway abundance analysis showed an increased abundance of the SCFA pathway, reduced histidine degradation ( Bacteroides sartorii, and Bacteroides caecimuris ), and LCFA production in the RCJ+DSS treated group, suggesting the promotion of good colonic health. Furthermore, increased T-reg (FOXP3+) cells in the colon were due to SCFAs produced by the gut microbiota, which was corroborated by an increase in IL-10, a vital anti-inflammatory cytokine. Thus, our study provides the first evidence that RCJ ameliorates colonic inflammation by modulating the gut microbiota.

A gut-restricted glutamate carboxypeptidase II inhibitor reduces monocytic inflammation and improves preclinical colitis

There is an urgent need to develop therapeutics for inflammatory bowel disease (IBD) because up to 40% of patients with moderate-to-severe IBD are not adequately controlled with existing drugs. Glutamate carboxypeptidase II (GCPII) has emerged as a promising therapeutic target. This enzyme is minimally expressed in normal ileum and colon, but it is markedly up-regulated in biopsies from patients with IBD and preclinical colitis models. Here, we generated a class of GCPII inhibitors designed to be gut-restricted for oral administration, and we interrogated efficacy and mechanism using in vitro and in vivo models. The lead inhibitor, (S)-IBD3540, was potent (half maximal inhibitory concentration = 4 nanomolar), selective, gut-restricted (AUCcolon/plasma > 50 in mice with colitis), and efficacious in acute and chronic rodent colitis models. In dextran sulfate sodium-induced colitis, oral (S)-IBD3540 inhibited >75% of colon GCPII activity, dose-dependently improved gross and histologic disease, and markedly attenuated monocytic inflammation. In spontaneous colitis in interleukin-10 (IL-10) knockout mice, once-daily oral (S)-IBD3540 initiated after disease onset improved disease, normalized colon histology, and attenuated inflammation as evidenced by reduced fecal lipocalin 2 and colon pro-inflammatory cytokines/chemokines, including tumor necrosis factor-α and IL-17. Using primary human colon epithelial air-liquid interface monolayers to interrogate the mechanism, we further found that (S)-IBD3540 protected against submersion-induced oxidative stress injury by decreasing barrier permeability, normalizing tight junction protein expression, and reducing procaspase-3 activation. Together, this work demonstrated that local inhibition of dysregulated gastrointestinal GCPII using the gut-restricted, orally active, small-molecule (S)-IBD3540 is a promising approach for IBD treatment.

Astragalus membranaceus as a Drug Candidate for Inflammatory Bowel Disease: The Preclinical Evidence

Inflammatory bowel disease (IBD) is a group of chronic inflammatory disorders that include Crohn's disease (CD) and ulcerative colitis (UC). Today, IBD has no successful treatment. As a result, it is of paramount importance to develop novel therapeutic agents for IBD prevention and treatment. Astragalus membranaceus (AMS) is a traditional Chinese medicine found in the AMS root. Modern pharmacological studies indicate that AMS and its constituents exhibit multiple bioactivities, such as anti-inflammatory, anti-oxidant, immune regulatory, anticancer, hypolipidemic, hypoglycemic, hepatoprotective, expectorant, and diuretic effects. AMS and its active constituents, which have been reported to be effective in IBD treatment, are believed to be viable candidate drugs for IBD treatment. These underlying mechanisms are associated with anti-inflammation, anti-oxidation, immunomodulation, intestinal epithelial repair, gut microbiota homeostasis, and improved energy metabolism. In this review, we summarize the efficacy and underlying mechanisms involved in IBD treatment with AMS and its active constituents in preclinical studies.

When less is more: Experimental Bishop-Koop technique for reduction in the use of laboratory animals for intestinal pathophysiological studies

The use of animals to gain knowledge and understanding of diseases needs to be reduced and refined. In the field of intestinal research, because of the complexity of the gut immune system, living models testing is mandatory. Based on the 3Rs (replacement, reduction and refinement) principles, we aimed to developed and apply the derived-intestinal surgical procedure described by Bishop and Koop (BK) in rats to refine experimental gastrointestinal procedures and reduce the number of animals used for research employing two models of intestinal inflammation: intestinal ischemia-reperfusion injury and chemical-induced colitis. Our results show the feasibility of the application of the BK technique in rodents, with good success after surgical procedure in both small and large intestine (100% survival, clinical recovery and weight regain). A considerable reduction in the use of the number of rats in both intestinal inflammation models (80% in case of intestinal ischemia-reperfusion damage and 66.6% in chemical-induced colitis in our experimental design) was achieved. Compared with conventional experimental models described by various research groups, we report excellent reproducibility of intestinal damage and functionality, survival rate and clinical status of the animals when BK is applied.

5-Aminosalicylic acid alters the gut microbiota and altered microbiota transmitted vertically to offspring have protective effects against colitis

Although many therapeutic options are available for inflammatory bowel disease (IBD), 5-aminosalicylic acid (5-ASA) is still the key medication, particularly for ulcerative colitis (UC). However, the mechanism of action of 5-ASA remains unclear. The intestinal microbiota plays an important role in the pathophysiology of IBD, and we hypothesized that 5-ASA alters the intestinal microbiota, which promotes the anti-inflammatory effect of 5-ASA. Because intestinal inflammation affects the gut microbiota and 5-ASA can change the severity of inflammation, assessing the impact of inflammation and 5-ASA on the gut microbiota is not feasible in a clinical study of patients with UC. Therefore, we undertook a translational study to demonstrate a causal link between 5-ASA administration and alterations of the intestinal microbiota. Furthermore, by rigorously controlling environmental confounders and excluding the effect of 5-ASA itself with a vertical transmission model, we observed that the gut microbiota altered by 5-ASA affected host mucosal immunity and decreased susceptibility to dextran sulfate sodium-induce colitis. Although the potential intergenerational transmission of epigenetic changes needs to be considered in this study, these findings suggested that alterations in the intestinal microbiota induced by 5-ASA directed the host immune system towards an anti-inflammatory state, which underlies the mechanism of 5-ASA efficacy.

Construction of a Synthetic Colostrum Substitute and Its Protection of Intestinal Cells against Inflammation in an In Vitro Model of Necrotizing Enterocolitis

Colostrum provides bioactive components that are essential for the colonization of microbiota in the infant gut, while preventing infectious diseases such as necrotizing enterocolitis. As colostrum is not always available from the mother, particularly for premature infants, effective and safe substitutes are keenly sought after by neonatologists. The benefits of bioactive factors in colostrum are recognized; however, there have been no accounts of human colostrum being studied during digestion of the lipid components or their self-assembly in gastrointestinal environments. Due to the weaker bile pool in infants than adults, evaluating the lipid composition of human colostrum and linking it to structural self-assembly behavior is important in these settings and thus enabling the formulation of substitutes for colostrum. This study is aimed at the rational design of an appropriate lipid component for a colostrum substitute and determining the ability of this formulation to reduce inflammation in intestinal cells. Gas chromatography was utilized to map lipid composition. The self-assembly of lipid components occurring during digestion of colostrum was monitored using small-angle X-ray scattering for comparison with substitute mixtures containing pure triglyceride lipids based on their abundance in colostrum. The digestion profiles of human colostrum and the substitute mixtures were similar. Subtle differences in lipid self-assembly were evident, with the substitute mixtures exhibiting additional non-lamellar phases, which were not seen for human colostrum. The difference is attributable to the distribution of free fatty acids released during digestion. The biological markers of necrotizing enterocolitis were modulated in cells that were treated with bifidobacteria cultured on colostrum substitute mixtures, compared to those treated with infant formula. These findings provide an insight into a colostrum substitute mixture that resembles human colostrum in terms of composition and structural behavior during digestion and potentially reduces some of the characteristics associated with necrotizing enterocolitis.

Protopine Alleviates Dextran Sodium Sulfate-Induced Ulcerative Colitis by Improving Intestinal Barrier Function and Regulating Intestinal Microbiota

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD), and its pathogenesis is related to intestinal mucosal barrier damage and gut microbiota imbalance. Protopine (PRO), an isoquinoline alkaloid, is one of the main anti-inflammatory ingredients of traditional Chinese medicine Macleaya cordata(Willd.) R. Br. This study investigated the effects of PRO on the intestinal mucosal barrier and gut microbiota in dextran sodium sulfate (DSS)-induced colitis mice. C57BL/6J mice were treated with 3% DSS in drinking water to induce acute colitis, while PRO was administered orally once daily for 7 days. The results showed that PRO administration significantly alleviated the symptoms of DSS-induced colitis in mice and inhibited the expression of inflammation-related genes. In addition, PRO restored the integrity of the intestinal barrier in colitis mice by restoring colonic mucin secretion and promoting the expression of tight junction proteins. Furthermore, PRO alleviated the DSS-induced gut microbiota dysbiosis by decreasing the abundance of Proteobacteria, Escherichia-Shigella and Enterococcus, as well as enhancing the abundance of beneficial bacteria, such as Firmicutes and Akkermansia. These findings suggested that PRO effectively alleviated DSS-induced ulcerative colitis by suppressing the expression of inflammation-related genes, maintaining the intestinal mucosal barrier and regulating the intestinal microbiota.

Microcystin-LR Induces and Aggravates Colitis through NLRP3 Inflammasome-Mediated Pyroptosis in Mice

Inflammatory bowel disease (IBD) is a chronic, lifelong gastrointestinal disease, characterized by periods of activity and remission. The etiology of IBD is closely related to environmental factors. Previous studies have shown that the cyanotoxin microcystin-LR (MC-LR) causes intestinal damage, even IBD. To explore MC-LR's effects and potential mechanisms on IBD occurrence and development, we used dextran-sulfate sodium gavage (DSS) and MC-LR together for the first time in mice. There were four groups of mice: (A) mice given PBS gavage (control, CT); (B) mice given 3% DSS gavage (DSS); (C) mice given 200 µg/kg MC-LR gavage (MC-LR); and (D) mice given 3% DSS + 200 µg/kg MC-LR gavage (DSS + MC-LR). Compared with the CT group, the MC-LR group and the DSS group demonstrated more severe colitis results, which presented as higher weight loss, an increased Disease Activity Index (DAI) score, shorter colon length, a higher degree of tissue structural damage, more apoptotic cells, and greater pro-inflammatory cytokines. Similarly, the DSS + MC-LR group showed more severe colitis compared with the DSS group. Subsequent experiments confirmed that MC-LR or DSS increased the expression of pyroptosis-related proteins mediated by the nucleotide-binding domain-like receptor protein 3 (NLRP3). Likewise, compared with the DSS group, the DSS + MC-LR group expressed these proteins at a higher level. In conclusion, our research is the first to show that MC-LR may induce colitis, and even IBD, through NLRP3 inflammasome-mediated pyroptosis, and it could aggravate DSS-induced colitis in the same way.

The Oral-Gut Axis: Periodontal Diseases and Gastrointestinal Disorders

One of the prospective sequelae of periodontal disease (PD), chronic inflammation of the oral mucosa, is the development of inflammatory gastrointestinal (GI) disorders due to the amplification and expansion of the oral pathobionts. In addition, chronic inflammatory diseases related to the GI tract, which include inflammatory bowel disease (IBD), can lead to malignancy susceptibility in the colon of both animals and humans. Recent studies suggest that dysbiosis of the oral microbiota can alter the microbial composition in relative abundance or diversity of the distal gut, leading to the progression of digestive carcinogenesis. The link between PD and specific GI disorders is also closely associated with the migration and colonization of periodontal pathogens and the subsequent microbe-reactive T cell induction within the intestines. In this review, an in-depth examination of this relationship and the accessibility of different mouse models of IBD and PD may shed light on the current dogma. As such, oral microbiota dysbiosis involving specific bacteria, including Fusobacterium nucleatum and Porphyromonas gingivalis, can ultimately lead to gut malignancies. Further understanding the precise mechanism(s) of the oral-gut microbial axis in PD, IBD, and colorectal cancer pathogenesis will be pivotal in diagnosis, prognosis, and future treatment.

bsh1 Gene of Lactobacillus plantarum AR113 Plays an Important Role in Ameliorating Western Diet-Aggravated Colitis

Western diet is thought to increase susceptibility to inflammatory bowel disease (IBD), and probiotics are a potential therapeutic agent for IBD. This study revealed the effects of Lactobacillus plantarum AR113 and L. plantarum AR113Δbsh1 on a dextran sulfate sodium (DSS)-induced colitis mouse model under the Western diet (WD). After four weeks of WD and low-sugar and low-fat diet (LD) intervention, induction with 3% DSS, and intragastric administration of probiotics, we found that L. plantarum AR113 could regulate blood glucose and lipid levels and have a certain protective effect on hepatocytes. Our results suggested that the L. plantarum AR113 alleviated DSS-induced colitis under the Western diet by improving dyslipidemia, repairing intestinal barrier dysfunction, and inhibiting the TLR4/Myd88/TRAF-6/NF-κB inflammatory pathway. However, these changes were not demonstrated in the L. plantarum AR113Δbsh1, and therefore, we reasoned that the presence of bsh1 may play a crucial role in the L. plantarum AR113 exerting its anti-inflammatory function. The relationship between bile salt hydrolase (BSH) and colitis was worthy of further exploration.

Therapeutic effect of Yiyi Fuzi Baijiang formula on TNBS-induced ulcerative colitis via metabolism and Th17/Treg cell balance

ETHNOPHARMACOLOGICAL RELEVANCE

Yiyi Fuzi Baijiang formula (YFB) is a traditional Chinese medicine prescription composed of Coix seed, Radix Aconiti Lateralis and Patrinia villosa, which has been used to treat ulcerative colitis (UC) for thousands of years.

AIM OF THE STUDY

To investigate the therapeutic effect and metabolic analysis of YFB formula on UC in rats induced by 2,4,6-trinitro-benzene sulfonic acid (TNBS).

MATERIALS AND METHODS

Six main alkaloids in the YFB formula were determined by UPLC‒MS/MS. The rat UC model was induced by TNBS, and the therapeutic effect of YFB formula on UC was evaluated by disease activity index (DAI) score and hematoxylin-eosin (HE) staining. UPLC-QTRAP-MS metabolomics technology was used to screen potential biomarkers for YFB treatment of UC in combination with multivariate data statistics and further analyze related metabolic pathways. Western blotting was used to detect the protein levels of NLRP1, NLRP3, NLRC4, ASC, pro-caspase1 and Caspase-1 in rat liver tissues. ELISA and immunohistochemistry were used to detect the contents of interleukin (IL)-17A, IL-21, IL-22, IL-6, TNF-α, IL-1β and IL-18 in rat serum and liver tissues.

RESULTS

The DAI scores of the YFB groups were significantly reduced, and colon tissue injury was significantly improved (p < 0.01). The results of metabolomics analysis revealed 29 potential biomarkers in serum and 27 potential biomarkers in liver. YFB formula can treat UC by affecting glycerophospholipid metabolism, primary bile acid biosynthesis, glyoxylic acid and dicarboxylic acid metabolism, and arginine and proline metabolism. Compared with the model group, the contents of IL-17A, IL-21, IL-22, IL-6, TNF-α, IL-1β and IL-18 in the YFB groups were decreased in a dose-dependent manner (p < 0.01). Compared with those in the model group, the protein levels of NLRP1, NLRP3, NLRC4, ASC, pro-caspase1 and Caspase-1 in the YFB groups were significantly decreased in a dose-dependent manner (p < 0.01).

CONCLUSIONS

The therapeutic effect of YFB formula on UC rats was dose dependent, and the effect of the YFB (2.046 g/kg) group was close to that of the positive group. YFB formula has an anti-inflammatory effect on UC by regulating the balance of Th17/Treg cells in rats.

Probing the effects of MR120 in preclinical chronic colitis: A first-in-class anti-IBD agent targeting the CCL20/CCR6 axis

Concerning the growing interest in the role played by the CCL20/CCR6 axis in IBD pathogenesis and in the search for novel anti-IBD small molecules, we have recently discovered the first small-molecule (MR120) endowed with protective action against TNBS-induced colitis and zymosan-induced peritonitis. This protective action occurs through interference with the CCL20/CCR6 signaling. The aim of the present work is to expand the preclinical investigation of MR120, evaluating its beneficial anti-inflammatory effect on a model of chronic colitis obtained by cyclically exposing C57BL/6 mice to 3% DSS. Subcutaneous administration of MR120 at 1 mg/kg, the same dose effective against acute inflammation, helped attenuate several systemic and local inflammatory responses induced by DSS. Besides significantly improving murine health conditions, MR120 counteracted mucosal macroscopic injury, the increase of colonic edema and neutrophils oxidative activity, and mitigated spleen enlargement, while not significantly lowering intestinal IL-6 concentration. Overall, repeated daily treatment with MR120 for approximately 30 days was well tolerated and showed moderate protection in a relevant model of chronic colitis, in line with the beneficial effect previously observed in acute models of intestinal inflammation. Although more potent analogues of MR120 will be needed to more fully evaluate their clinical translatability, the present work provides a valuable example of in vivo efficacy of CCL20/CCR6 modulators in a chronic model of IBD.

Highlights on two decades with microbiota and inflammatory bowel disease from etiology to therapy

Inflammatory Bowel diseases (IBDs) constitute a complex panel of disorders characterized with chronic inflammation affecting the alimentary canal along with extra intestinal manifestations. Its exact etiology is still unknown; however, it seems to be the result of uncharacterized environmental insults in the intestine and their immunological consequences along with dysbiosis, in genetically predisposed individuals. It was the main target of our team since 2002 to explore the etiology of IBD and the related role of bacteria. For almost two decades, our laboratory, among others, has been involved in the reciprocal interaction between the host gastrointestinal lining and the homing microbiota. In the first decade, the attention of scientists focused on the possible role of enteropathogenic E. coli and its relationship to the mechanistic pathways involved in IBD induced in both rats and mice by chemicals like Iodoacetamide, Dextran Sodium Sulfate, Trinitrobenzene, thus linking microbial alteration to IBD pathology. A thorough characterization of the various models was the focus of research in addition to exploring how to establish an active homeostatic composition of the commensal microbiota, including its wide diversity by restoration of gut microbiota by probiotics and moving from dysbiosis to eubiosis. In the last six years and in order to effectively translate such findings into clinical practice, it was critical to explore their relationship to colorectal cancer CRC both in solid tumors and chemically induced CRC. It was also critical to explore the degree of intestinal dysbiosis and linking to IBD, CRC and diabetes. Remarkably, the active mechanistic pathways were proposed as well as the role of microbiota or bacterial metabolites involved. This review covers two decades of investigations in our laboratory and sheds light on the different aspects of the relationship between microbiota and IBD with an emphasis on dysbiosis, probiotics and the multiple mechanistic pathways involved.

Aspergillus cristatus attenuates DSS-induced intestinal barrier damage through reducing the oxidative stress, regulating short-chain fatty acid and inhibiting MAPK signaling pathways

BACKGROUND

Probiotics are regarded as a promising strategy for relieving colitis caused by dextran sulfate sodium (DSS). One of the dominant probiotic fungi in Fuzhuan brick tea is identified as Aspergillus cristatus, but whether it can effectively improve colitis remains poorly understood. Here, the improving effect of A. cristatus on colitis was investigated.

RESULTS

Our results showed that A. cristatus intervention prominently alleviated gut damage as evidenced by the inhibition of shortened colon length, goblet cell depletion, and histological injury. Mechanistically, after administration with low concentrations of A. cristatus H-1 and A. cristatus S-6, the expression of interleukin-6, tumor necrosis factor-α, interleukin-1β, nitric oxide, and malondialdehyde were significantly downregulated, and the content of glutathione, catalase, interleukin-10, immunoglobulin G, claudin-1, occludin, and zonula occludens-1 were effectively upregulated. More importantly, live A. cristatus supplementation lightened DSS-induced gut barrier damage by suppressing activation of the mitogen-activated protein kinase (MAPK) signaling pathway, increasing the synthesis of short-chain fatty acids (SCFAs) and stimulating the increase in peroxisome proliferator-activated receptor γ expression.

CONCLUSION

Together, A. cristatus can attenuate DSS-induced intestinal barrier damage through reducing the oxidative stress, regulating SCFA and inhibiting MAPK signaling pathways (P38/JNK/ERK). Our findings indicate that A. cristatus replenishment has potential as a new probiotic fungi to reduce DSS-induced colitis. © 2022 Society of Chemical Industry.

Slc11a1 gene polymorphism influences dextran sulfate sodium (DSS)-induced colitis in a murine model of acute inflammation

Ulcerative Colitis (UC) is an inflammatory disease characterized by colonic mucosal lesions associated with an increased risk of carcinogenesis. UC pathogenesis involves environmental and genetic factors. Genetic studies have indicated the association of gene variants coding for the divalent metal ion transporter SLC11A1 protein (formerly NRAMP1) with UC susceptibility in several animal species. Two mouse lines were genetically selected for high (AIRmax) or low (AIRmin) acute inflammatory responses (AIR). AIRmax is susceptible, and AIRmin is resistant to DSS-induced colitis and colon carcinogenesis. Furthermore, AIRmin mice present polymorphism of the Slc11a1 gene. Here we investigated the possible modulating effect of the Slc11a1 R and S variants in DSS-induced colitis by using AIRmin mice homozygous for Slc11a1 R (AIRmin^RR) or S (AIRmin^SS) alleles. We evaluated UC by the disease activity index (DAI), considering weight loss, diarrhea, blood in the anus or feces, cytokines, histopathology, and cell populations in the distal colon epithelium. AIRmin^SS mice have become susceptible to DSS effects, with higher DAI, IL6, G-CSF, and MCP-1 production and morphological and colon histopathological alterations than AIRmin^RR mice. The results point to a role of the Slc11a1 S allele in DSS colitis induction in the genetic background of AIRmin mice.

Serum lactate dehydrogenase is associated with impaired lung function: NHANES 2011-2012

BACKGROUND

Serum lactate dehydrogenase levels reflect disease status in a variety of organs, but its role in indicating pulmonary function is not yet clear. Therefore, this study explored the correlation between pulmonary function and serum lactate dehydrogenase, and investigated thresholds for changes in pulmonary function indicators in the total population as well as in different strata of the population.

METHODS

Based on data from the National Health and Nutrition Examination Survey (NHANES) 2011-2012 (n = 3453), univariate and stratified analyses were performed to investigate factors associated with pulmonary function, and multiple regression analysis was used to further investigate the specific relationship with serum lactate dehydrogenase. Smoothed curve fitting, threshold effect and saturation effect analysis were used to explore the threshold level of serum lactate dehydrogenase at the onset of changes in pulmonary function indicators.

RESULTS

Adjusted smoothed curve fit plots showed a linear relationship between serum lactate dehydrogenase levels and forced vital capacity and forced expiratory volume in one second: for each 1 U/L increase in serum lactate dehydrogenase levels, forced vital capacity decreased by 1.24 mL (95% CI = -2.05, -0.42, P = 0.0030) and forced expiratory volume in one second by 1.11 mL (95% CI = -1.82, -0.39, P = 0.0025).

CONCLUSIONS

Serum lactate dehydrogenase was negatively and linearly correlated with pulmonary function indices in the total population analyzed. Based on the total population and different population stratifications, this study determined the threshold values of serum lactate dehydrogenase at the onset of decline of pulmonary function in different populations. This provides a new serological monitoring indicator for patients suffering from respiratory diseases and has implications for patients with possible clinical impairment of pulmonary function. However, our cross-sectional study was not able to determine a causal relationship between these two factors, and further research is needed.

Eudragit-coated chitosan-tripterygium glycoside conjugate microspheres alleviate DSS-induced experimental colitis by inhibiting the TLR4/NF-κB signaling pathway

OBJECTIVE

Tripterygium glycoside (TG) is a fat-soluble extract of Tripterygium wilfordii, with anti-inflammatory properties associated with TLR signaling pathways. This study constructed a targeted delivery system for experimental colitis, namely, eudragit (EuL)-coated chitosan (Ch)-TG conjugate microspheres (Ch-TG-MS/EuL), and evaluated its therapeutic efficacy and underlying mechanisms.

METHODS

Ch-TG-MS was fabricated using emulsification cross-linking technique and then coated with EuL to create Ch-TG-MS/EuL. Drug release properties were assessed using a dialysis model. Additionally, the therapeutic benefits of Ch-TG-MS/EuL on colonic inflammation and its specific effect on TLR4/NF-κB signaling in intestinal mucosa were evaluated in vivo using a DSS-induced murine colitis model.

RESULTS

The Ch-TG-MS/EuL microspheres appeared as yellow powders with a slightly enlarged shape, rough surface, and adhesions. The Ch-TG-MS/EuL formulations also exhibited high entrapment efficiency and drug loading rate. High-performance liquid chromatography revealed that Ch-TG-MS/EuL exhibited a less intense peak than free TG, confirming that the drug is contained within the formulation. Free TG displayed explosive release within the first 5 h of administration, while Ch-TG-MS/EuL prevented the pre-mature release of TG and exhibited controllable release up to 24 h. In vivo, noticeable amelioration of intestinal mucosal tissue destruction was achieved with Ch-TG-MS/EuL compared to free TG. Additionally, immunohistochemical and western blotting results revealed that Ch-TG-MS/EuL markedly down-regulated the expression of intestinal mucosal TLR4, MyD88, and NF-κB p65. Hence, Ch-TG-MS/EuL may ameliorate the colon inflammatory response by inhibiting the hyperactivation of TLR4/NF-κB signaling.

CONCLUSION

Novel Ch-TG-MS/EuL preparation may represent a colonic delivery system for UC therapeutics by inhibiting TLR4/NF-κB hyperactivation.

DATA AVAILABILITY

All experimental data supporting the conclusions of this study are available from the corresponding author on reasonable request.

Citrate and hydroxycinnamate derivatives from Mume Fructus protect LPS-injured intestinal epithelial cells by regulating the FAK/PI3K/AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Mume Fructus (MF) is processed from the near-ripe fruit of Prunus mume (Siebold) Siebold & Zucc by drying at low temperature until the color turns black. MF is often used in Chinese medicine for the treatment of chronic diarrhea and dysentery. Previous studies have shown that the active components of MF against Crohn's disease (CD) are mainly citrate and hydroxycinnamate derivatives, which can alleviate the CD-induced inflammatory response and intestinal barrier damage. However, their molecular mechanisms on CD still need further elucidation.

AIM OF THE STUDY

To investigate the protective effects and underlying mechanisms of citrate and hydroxycinnamate derivatives in MF on intestinal epithelial injury.

MATERIALS AND METHODS

Network pharmacology technology was used to predict the anti-CD targets and molecular mechanisms of 4 citrate and 11 hydroxycinnamate derivative prototypes and 5 hydroxycinnamate derivative metabolites in the 40% ethanol fraction of MF (MFE40), the active anti-CD ingredient group of MF. Lipopolysaccharide (LPS)-treated IEC-6 cells were used to investigate the effects of the above components on the proliferation of damaged IEC-6 cells and to verify the molecular mechanism of their regulation on the FAK/PI3K/AKT signaling pathways for the promotion of the proliferation of IEC-6 cells.

RESULTS

A "compound-target-pathway" network was constructed based on network pharmacology analysis, including 20 citrate and hydroxycinnamate derivatives that target 316 core proteins and 36 CD-related pathways, of which PI3K-AKT pathway and focal adhesion were the most enriched pathways. Further cell validation experiments showed that 1 citric acid (CA) compound and 10 hydroxycinnamate derivatives, including 3-O-caffeoylquinic acid (3CQA), 4-O-caffeoylquinic acid (4CQA), 5-O-caffeoylquinic acid (5CQA), caffeic acid (CFA), p-coumaric acid (PCMA), m-coumaric acid (MCMA), ferulic acid (FUA), isoferulic acid (IFUA), 3-hydroxyphenylpropionic acid (3HPPA) and hippuric acid (HPP), could promote the proliferation of IEC-6 cells and inhibit the damage of LPS to IEC-6 cells. Ethyl caffeate (ECFA), a hydroxycinnamic acid derivative, had no effect on promoting the proliferation of IEC-6 cells and was weak in inhibiting the damage of IEC-6 cells caused by LPS. Further mechanistic verification experiments showed that 7 citrate and hydroxycinnamate derivatives (CA, CFA, 3CQA, MCMA, FUA, 3HPPA, and HPP) could upregulate the expression of p-FAK, p-PI3K, and p-AKT proteins. Among them, CA had the better effect on activating the FAK-PI3K-AKT signaling pathway.

CONCLUSIONS

Citrate and hydroxycinnamate derivatives in MF can ameliorate LPS-induced intestinal epithelial cell injury to demonstrate potential for Crohn's disease alleviation. This protective effect can be achieved by upregulating FAK/PI3K/AKT pathway.