Pathogenesis Of Inflammatory Bowel Disease Research Articles

The role of enhanced expression of Cx43 in patients with ulcerative colitis.

The pathogenesis of ulcerative colitis (UC) involves chronic inflammation of the submucosal layer and disruption of epithelial barrier function within the gastrointestinal tract. Connexin 43 (Cx43) has been implicated in the pathogenesis of intestinal inflammation and its associated carcinogenic effects. However, a comprehensive analysis of Cx43's role in mucosal and peripheral immunity in patients with UC is lacking. In this study, the colon tissues of patients with UC exhibited severe damage to the intestinal mucosal barrier, resulting in a significant impairment of junctional communication as observed by transmission electron microscopy. The mRNA expression of Cx43 was found to be significantly elevated in the UC group compared to the control group, as determined using the Affymetrix expression profile chip and subsequently validated using qRT-PCR. The immunofluorescence analysis revealed a significantly higher mean fluorescence intensity of Cx43 in the UC group compared to the control group. Additionally, Cx43 was observed in both the cell membrane and nucleus, providing clear evidence of nuclear translocation. The proportion of Cx43 in the UC group for CD4+ and CD8+ T lymphocytes was increased in the control group, but only the proportion of Cx43 for CD8+ T lymphocytes showed significant difference by flow cytometry. The involvement of Cx43 in the pathogenesis of UC and its potential role in mucosal immunity warrants further investigation, as it holds promise as a prospective biomarker and therapeutic target for this condition. The proportion of Cx43 in the UC group for CD4+ and CD8+ T lymphocytes was increased in the control group, but only the proportion of Cx43 for CD8+ T lymphocytes showed a significant difference.

Gut Microbiota Profile Changes in Patients with Inflammatory Bowel Disease and Non-Alcoholic Fatty Liver Disease: A Metagenomic Study

Gut microbiota imbalances have a significant role in the pathogenesis of Inflammatory Bowel Disease (IBD) and Non-Alcoholic Fatty Liver Disease (NAFLD). Herein, we compared gut microbial composition in patients diagnosed with either IBD or NAFLD or a combination of both. Seventy-four participants were stratified into four groups: IBD-NAFLD, IBD-only, NAFLD-only patients, and healthy controls (CTRLs). The 16S rRNA was sequenced by Next-Generation Sequencing. Bioinformatics and statistical analysis were performed. Bacterial α-diversity showed a significant lower value when the IBD-only group was compared to the other groups and particularly against the IBD-NAFLD group. β-diversity also showed a significant difference among groups. The higher Bacteroidetes/Firmicutes ratio was found only when comparing IBD groups and CTRLs. Comparing the IBD-only group with the IBD-NAFLD group, a decrease in differential abundance of Subdoligranulum, Parabacteroides, and Fusicatenibacter was found. Comparing the NAFLD-only with the IBD-NAFLD groups, there was a higher abundance of Alistipes, Odoribacter, Sutterella, and Lachnospira. An inverse relationship in the comparison between the IBD-only group and the other groups was shown. For the first time, the singularity of the gut microbial composition in IBD and NAFLD patients has been shown, implying a potential microbial signature mainly influenced by gut inflammation.

Readily Available Oral Prebiotic Protein Reactive Oxygen Species Nanoscavengers for Synergistic Therapy of Inflammation and Fibrosis in Inflammatory Bowel Disease.

A significant gap exists in the demand for safe and effective drugs for inflammatory bowel disease (IBD), and its associated intestinal fibrosis. As oxidative stress plays a central role in the pathogenesis of IBD, astaxanthin (AST), a good antioxidant with high safety, holds promise for treating IBD. However, the application of AST is restricted by its poor solubility and easy oxidation. Herein, different protein-based nanoparticles (NPs) are fabricated for AST loading to identify an oral nanovehicle with potential clinical applicability. Through systematic validation via molecular dynamics simulation and in vitro characterization of properties, whey protein isolate (WPI)-driven NPs using a simple preparation method without the need for cross-linking agents or emulsifiers were identified as the optimal carrier for oral AST delivery. Upon oral administration, the WPI-driven NPs, benefiting from the intrinsic pH sensitivity and mucoadhesive properties, effectively shielded AST from degradation by gastric juices and targeted release of AST at intestinal lesion sites. Additionally, the AST NPs displayed potent therapeutic efficacy in both dextran sulfate sodium (DSS)-induced acute colitis and chronic colitis-associated intestinal fibrosis by ameliorating inflammation, oxidative damage, and intestinal microecology. In conclusion, the AST WPI NPs hold a potential therapeutic value in treating inflammation and fibrosis in IBD.

Сучасні уявлення про патогенетичні механізми розвитку запальних захворювань кишківника

The high frequency of prevalence and the decrease in the quality of life of patients determine the urgency of studying the peculiarities of the etiology and pathogenesis of inflammatory bowel diseases. The difficulty of finding new non-invasive markers lies in the lack of a clear understanding of the molecular mechanisms of the pathogenesis of these diseases. One of the promising directions in the diagnosis of chronic inflammatory diseases is the identification of specific miRNA molecules in blood serum, which act as powerful negative regulators of gene expression.

A prediction of the CRNDE role by modulating NF-κB pathway in inflammatory bowel disease (IBD)

Long non-coding RNAs (lncRNAs) regulate multiple pathways and cellular mechanisms. Recent research has emphasized their involvement in the pathogenesis of complex diseases, such as Inflammatory Bowel Disease (IBD) which is characterized by chronic inflammation of the intestines. The two most common types of IBD are ulcerative colitis and Crohn's disease. CRNDE lncRNA was initially detected in colorectal cancer (CRC) and found to be involved in the tumorigenesis pathways. Further studies revealed the role of CRNDE in activating inflammation and promoting the release of inflammatory cytokines. This study utilizes the RNA-seq data analysis and bioinformatics tools to clarify the role of CRNDE in the IBD pathogenesis and confirms its expression in inflamed HT-29 and Caco-2 cell lines and also colonic and blood samples of UC patients and controls ex vivo. Based on our results, CRNDE was significantly upregulated in IBD samples compared to controls in RNA-seq data analysis and Real-time PCR of inflamed HT-29 cell line and colonic biopsies from UC patients. Additionally, predicted that its expression is positively correlated with the pro-inflammatory cytokines production. CRNDE interactions was investigated with several inflammation-related miRNAs and regulatory proteins computationally. Thus, CRNDE upregulation in the colon of IBD patients could be involved in IBD pathogenesis by promoting inflammatory pathways and targeting anti-inflammatory miRNAs.

Exploring the Gut Microbiome’s Role in Inflammatory Bowel Disease: Insights and Interventions

Inflammatory Bowel Disease (IBD), encompassing Crohn’s disease (CD) and ulcerative colitis (UC), is a chronic and relapsing inflammatory condition of the intestine that significantly impairs quality of life and imposes a heavy burden on healthcare systems globally. While the exact etiology of IBD is unclear, it is influenced by genetic, environmental, immunological, and microbial factors. Recent advances highlight the gut microbiome’s pivotal role in IBD pathogenesis. The microbial dysbiosis characteristic of IBD, marked by a decline in beneficial bacteria and an increase in pathogenic microbes, suggests a profound connection between microbial imbalance and disease mechanisms. This review explores diagnostic approaches to IBD that integrate clinical assessment with advanced microbiological analyses, highlighting the potential of microbiome profiling as a non-invasive diagnostic tool. In addition, it evaluates conventional and emerging treatments and discusses microbiome-targeted intervention prospects, such as probiotics, symbiotics, and faecal microbiota transplantation. The necessity for future research to establish their efficacy and safety is emphasised.

Role of IL-33/ST2 Pathway in Inflammatory Bowel Disease: An Overview and Future Perspectives

Inflammatory bowel disease (IBD) represents a heterogenous and complex group of idiopathic chronic inflammatory conditions affecting the gastrointestinal tract and other extraintestinal systems with rising global incidences. The interplay of genetic predisposition and environmental factors contributes to its pathogenesis. Among the key cytokines implicated in IBD molecular alterations, IL-33 stands out for its multifaceted roles in both pathogenesis and repair mechanisms. IL-33, known for its action in initiating immune responses, is closely associated with Th2 immunity and is considered a potent inflammatory factor with dual functions, acting both as a pro-inflammatory cytokine and a transcriptional regulator. Primarily expressed by non-hematopoietic cells in the gastrointestinal tract, IL-33 interacts with its receptor, ST2, to modulate immune responses. In IBD, dysregulated IL-33 expression exacerbates mucosal inflammation, compromising barrier integrity and promoting tissue damage and fibrosis. Additionally, IL-33 plays a complex role in IBD-related colorectal cancer (CRC), affecting tumor progression and angiogenesis. This review summarizes the multifaceted roles of IL-33 in gastrointestinal health and disease, emphasizing its significance in the pathogenesis of IBD and CRC. Moreover, we thought it of interest to provide new insights into potential therapeutic avenues targeting IL-33 signaling for the management of these debilitating conditions.

MTOR promotes an inflammatory response through the HIF1 signaling pathway in ulcerative colitis

The imbalance between T helper cell 17 （Th17）and regulatory T cells (Treg) cells leading to inflammation has an important role in the pathogenesis of ulcerative colitis (UC). Mammalian target of rapamycin (mTOR) can regulate the differentiation of T cells, but the specific pathway leading mTOR to regulate Th17/Treg cells in UC remains unclear. Our aim with this study was to investigate the effects of mTOR overexpression and silencing on the hypoxia inducible factor-1α (HIF-1α) − Th17/Treg signaling pathway. To mimic a human study, we established a colon cancer epithelial cell line (HT-29) co-culture system with human CD4+ T cells, and we treated the cells with TNF-α. We observed the effects of mTOR on the HIF-Th17/Treg signaling pathway to determine whether mTOR is involved in the regulatory mechanism.Under the stimulation of TNF-α, the levels of HIF-1α in CD4+T cells were increased in the HT-29 co-culture with CD4+ T cells, promoting glycolysis, increasing the Th17 proportion, decreasing the Treg proportion, increasing the pro-inflammatory factors levels, and decreasing the anti-inflammatory factors levels. Moreover, after mTOR silencing, the HIF-1α level and cell glycolysis levels decreased, Th17 cell differentiation decreased, the pro-inflammatory factor levels decreased, and the anti-inflammatory factor levels increased. In contrast, mTOR overexpression lead to the opposite results.mTOR promotes inflammation by regulating the HIF signaling pathway during UC, and silencing mTOR may alleviate inflammation. An mTOR inhibitor is a potential therapeutic target for UC treatment.

Assessment of the content of short-chain fatty acids in ulcerative colitis as an indicator of the patient's metabolic health

Numerous studies show that in the pathogenesis of ulcerative colitis (UC), a significant role is played by a change in the diversity of the intestinal microflora, which is associated with fewer bacteria producing short-chain fatty acids (SCFAs). SCFCS affect the differentiation and activation of cells of the immune system, play a protective role in maintaining the integrity of the epithelial barrier, participate in the regulation of intestinal peristalsis and blood supply to its wall, muscle anabolism, bioavailability of amino acids.The aim of the study. To evaluate the content of SCLC in the feces of UC patients with varying degrees of severity of the current attack, as well as to investigate the relationship between the content of SCLC with dietary characteristics, body mass index (BMI), and dyspenia.Materials and methods. The study involved 80 UC patients, conducted a survey, objective examination, filling out medical history and outpatient records, blood and stool sampling. The content of SCLC was determined in feces. The study of nutritional characteristics in patients with UC was conducted using a standardized questionnaire of the WHO CINDI program. Statistical methods: median (Me), upper and lower quartiles (P25, P75) were calculated; Mann-Whitney criterion; Kolmogorov-Smirnov criterion; nonparametric correlation analysis was performed.Results. The absolute content of SCFCS in the feces of patients with UC is lower than the reference values. The relative content of propionic acid in the subgroup with severe attack was significantly lower than in the remission subgroup, in the subgroup with mild and moderate attack of the disease. In patients with body weight deficiency, the relative content of propionic acid is lower than in UC patients with normal or overweight. A positive relationship was found between the total content of SCFCS in feces and the amount of dietary fiber consumed in the form of fruits and vegetables. In patients with dinapenia, the relative content of butyric acid in feces is significantly lower than in patients without dinapenia.

Mesenteric Lymphatic B Cells Migrate to the Intestine and Aggravate DSS-Induced Colitis via the CXCR5–CXCL13 Axis

Mesenteric Lymphatic B Cells Migrate to the Intestine and Aggravate DSS-Induced Colitis via the CXCR5–CXCL13 Axis

Bacterial dysbiosis in newly diagnosed treatment naïve pediatric ulcerative colitis in Saudi Arabia.

The role of microbiota in the pathogenesis of ulcerative colitis (UC) has been increasingly recognized. However, most of the reports are from Western populations. In Middle Eastern countries, including Saudi Arabia, little is known about the role of microbiota. Therefore, our aim was to describe the bacterial microbiota profile and signature in pediatric UC in Saudi Arabia. Twenty children with UC and 20 healthy controls enrolled in the study gave stool samples. Twenty rectal mucosal samples were taken from UC and 20 from non-UC controls. Inclusion criteria included newly diagnosed and untreated children and lack of antibiotic exposure for at least 6 months before stool collection was required for children with UC and controls. Bacterial deoxyribonucleic acid was extracted and sequenced using shotgun metagenomic analysis. Statistical analysis included Shannon alpha diversity metrics, Bray-Curtis dissimilarity, DESeq2, and biomarker discovery. The demographic characteristics were similar in children with UC and controls. There was a significant reduction in alpha diversity (P = 0.037) and beta diversity in samples from children with UC (P = 0.001). Many taxa were identified with log2 abundance analysis, revealing 110 and 102 species significantly depleted and enriched in UC, respectively. Eleven bacterial species' signatures were identified. In Saudi Arabian children with UC, we demonstrate a dysbiosis similar to reports from Western populations, possibly related to changes of lifestyle. Microbial signature discovery in this report is an important contribution to research, leading to the development of adjunctive non-invasive diagnostic options in unusual cases of UC.

Role of Vitamin D in the Pathogenesis of Inflammatory Bowel Diseases: Literature Review

The pathogenesis of inflammatory bowel diseases still remains unclear nowadays. Genetic disposition, impaired immune regulation, disturbance in intestinal microbiota composition, exposure to environmental factors are associated with the development of inflammation in intestinal mucosa and increased epithelial penetrance that define disease's development and progression. There is a theory in scientific literature that vitamin D deficiency (among other environmental factors) increases the risk of inflammatory bowel disease. However, the role of vitamin D in the development of gastrointestinal tract diseases remains poorly studied. This article presents current data on the vitamin D effect on the intestinal mucosa barrier function, on the immune system and on the intestinal microbiota in the context of inflammatory bowel diseases pathogenesis.

Targeting programmed cell death in inflammatory bowel disease through natural products: New insights from molecular mechanisms to targeted therapies.

Inflammatory bowel disease (IBD) is an autoimmune disorder primarily characterized by intestinal inflammation and recurrent ulceration, leading to a compromised intestinal barrier and inflammatory infiltration. This disorder's pathogenesis is mainly attributed to extensive damage or death of intestinal epithelial cells, along with abnormal activation or impaired death regulation of immune cells and the release of various inflammatory factors, which contribute to the inflammatory environment in the intestines. Thus, maintaining intestinal homeostasis hinges on balancing the survival and functionality of various cell types. Programmed cell death (PCD) pathways, including apoptosis, pyroptosis, autophagy, ferroptosis, necroptosis, and neutrophil extracellular traps, are integral in the pathogenesis of IBD by mediating the death of intestinal epithelial and immune cells. Natural products derived from plants, fruits, and vegetables have shown potential in regulating PCD, offering preventive and therapeutic avenues for IBD. This article reviews the role of natural products in IBD treatment by focusing on targeting PCD pathways, opening new avenues for clinical IBD management.

17β-estradiol promotes myeloid-derived suppressor cells functions and alleviates inflammatory bowel disease by activation of Stat3 and NF-κB signalings

Inflammatory bowel disease (IBD) describes a group of clinically common autoimmune diseases characterized by chronic intestinal inflammation, with gender differences in prevalence. Estrogen has been previously shown to exert anti-inflammatory action in IBD development, however, the mechanisms remain obscure. Recent research has revealed that myeloid-derived suppressor cells (MDSCs) play a protective role in IBD pathogenesis. To investigate the molecular mechanisms of estrogen steroid 17β-estradiol (E2) in IBD progression, we established IBD mouse models (DNB-induced) with or without prior ovariectomy (OVX) and E2 implantation. We found that OVX led to worse IBD symptoms and reduced MDSCs frequency, whereas E2 significantly alleviated these effects in vivo. Moreover, in vitro experiments showed that E2 promoted the proliferation and immunosuppressive function of MDSCs through phosphorylation of Stat3 and p65. Mechanistically, E2-mediated Stat3/p65 phosphorylation depends on the interaction between HOTAIR, a long non-coding RNA that are well-known in MDSCs proliferation, and Stat3/p65 respectively. In conclusion, our study revealed that E2 promotes the expansion and immunosuppressive function of MDSCs, and thus diminished the occurrence and development of IBD.

Origin and Function of Monocytes in Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a chronic disease resulting from the interaction of various factors such as social elements, autoimmunity, genetics, and gut microbiota. Alarmingly, recent epidemiological data points to a surging incidence of IBD, underscoring an urgent imperative: to delineate the intricate mechanisms driving its onset. Such insights are paramount, not only for enhancing our comprehension of IBD pathogenesis but also for refining diagnostic and therapeutic paradigms. Monocytes, significant immune cells derived from the bone marrow, serve as precursors to macrophages (Mφs) and dendritic cells (DCs) in the inflammatory response of IBD. Within the IBD milieu, their role is twofold. On the one hand, monocytes are instrumental in precipitating the disease's progression. On the other hand, their differentiated offsprings, namely moMφs and moDCs, are conspicuously mobilized at inflammatory foci, manifesting either pro-inflammatory or anti-inflammatory actions. The phenotypic spectrum of these effector cells, intriguingly, is modulated by variables such as host genetics and the subtleties of the prevailing inflammatory microenvironment. Notwithstanding their significance, a palpable dearth exists in the literature concerning the roles and mechanisms of monocytes in IBD pathogenesis. This review endeavors to bridge this knowledge gap. It offers an exhaustive exploration of monocytes' origin, their developmental trajectory, and their differentiation dynamics during IBD. Furthermore, it delves into the functional ramifications of monocytes and their differentiated progenies throughout IBD's course. Through this lens, we aspire to furnish novel perspectives into IBD's etiology and potential therapeutic strategies.

A Direct Link Implicating Loss of SLC26A6 to Gut Microbial Dysbiosis, Compromised Barrier Integrity and Inflammation

BackgroundPutative anion transporter-1 (PAT1, SLC26A6) plays a key role in intestinal oxalate and bicarbonate secretion. PAT1 knockout (PKO) mice exhibit hyperoxaluria and nephrolithiasis. Notably, diseases such as inflammatory bowel diseases (IBD) are also associated with higher risk of hyperoxaluria and nephrolithiasis. However, the potential role of PAT1 deficiency in gut barrier integrity and susceptibility to colitis is currently elusive. MethodsAge-matched PKO and wild-type (WT) littermates were administered 3.5%-DSS in drinking water for 6 days. Ileum and colon of control and treated mice were harvested. mRNA and protein expression of tight junction (TJ) proteins were determined by RT-PCR and western blotting. Severity of inflammation was assessed by measuring diarrheal phenotype, cytokine expression and H&E staining. Gut microbiome and associated metabolome were analyzed by 16S rRNA sequencing and mass spectrometry, respectively. ResultsPKO mice exhibited significantly higher loss of body weight, gut permeability, colonic inflammation, and diarrhea in response to DSS treatment. Additionally, PKO mice showed microbial dysbiosis and significantly reduced levels of butyrate and butyrate-producing microbes compared to controls. Cohousing WT and PKO mice for 4 weeks resulted in PKO-like signatures on the expression of TJ proteins in the colon of WT mice. ConclusionOur data demonstrate that loss of PAT1 disrupts gut microbiome and related metabolites, decreases gut barrier integrity, and increases host susceptibility to intestinal inflammation. These findings, thus, highlight a novel role of the oxalate transporter PAT1 in promoting gut barrier integrity and its deficiency appears to contribute to the pathogenesis of IBD.

Effects of DNA methylation and its application in inflammatory bowel disease (Review).

Inflammatory bowel disease (IBD) is marked by persistent inflammation, and its development and progression are linked to environmental, genetic, immune system and gut microbial factors. DNA methylation (DNAm), as one of the protein modifications, is a crucial epigenetic process used by cells to control gene transcription. DNAm is one of the most common areas that has drawn increasing attention recently, with studies revealing that the interleukin (IL)‑23/IL‑12, wingless‑related integration site, IL‑6‑associated signal transducer and activator of transcription 3, suppressor of cytokine signaling 3 and apoptosis signaling pathways are involved in DNAm and in the pathogenesis of IBD. It has emerged that DNAm‑associated genes are involved in perpetuating the persistent inflammation that characterizes a number of diseases, including IBD, providing a novel therapeutic strategy for exploring their treatment. The present review discusses DNAm‑associated genes in the pathogenesis of IBD and summarizes their application as possible diagnostic, prognostic and therapeutic biomarkers in IBD. This may provide a reference for the particular form of IBD and its related methylation genes, aiding in clinical decision‑making and encouraging therapeutic alternatives.

The Role of the Bile Acid-intestinal Flora Axis in the Pathogenesis of Ulcerative Colitis

The Role of the Bile Acid-intestinal Flora Axis in the Pathogenesis of Ulcerative Colitis

Mangiferin, A Naturally Occurring Glucosylxanthone, Induces Apoptosis in Caco-2 Cells In Vitro and Exerts Protective Effects on Acetic Acid-Induced Ulcerative Colitis in Mice through the Regulation of NLRP3.

Inflammatory bowel diseases (IBD), an inflammatory disease, include Crohn's disease and ulcerative colitis. Dysregulated autoimmune response to gut dysbiosis is mainly involved in the pathogenesis of IBD and is triggered by various inciting environmental factors. With its rising prevalence in every continent, IBD has evolved into a global disease, which is on the rise, affecting people of all ages. There is a growing incidence of IBD in the elderly population, as evidenced by epidemiological data. IBD is characterized by an inflammatory process that requires a lifelong treatment. The main challenge in IBD management is the adverse side effects associated with almost all of the currently available drugs. Hence, there is a search for drugs with more efficacy and fewer side effects. Natural products with great structural diversity and ease of modification chemically are being explored, as they were shown to control IBD by safely suppressing pro-inflammatory pathways. The present study aims at understanding the role of mangiferin, a COX-2 inhibitor isolated from tubers of Pueraria tuberosa in the treatment of IBD and colon cancer, in vitro on the Caco-2 human colon cancer cell line and in vivo in the acetic acid-induced IBD mouse model. In the acetic acid-induced colitis model, it prevented the decrease in length of the colon, mucosal erosion, and cellular infiltration in a dose-dependent manner. The expression levels of various pro-inflammatory markers like COX-2, IL1β, TNF-α, INF-γ, IL-6, NLRP3, and caspase-1 were downregulated in an acetic acid-induced mouse model on treatment with mangiferin in a dose dependent manner. Mangiferin also showed anticancer effects on Caco-2 cells by increasing the expression of Fas ligand, Fas receptor, FADD, caspase-8, and caspase-3 proteins, whereas Bid and Bcl-2 proteins showed decreased expression. These data suggest that mangiferin, an inhibitor of COX, induces apoptosis in colon cancer cells in vitro and protects mice from acetic acid-induced colitis in vivo.

Methionine-choline deficient diet deteriorates DSS-induced murine colitis through disturbance of gut microbes and infiltration of macrophages.

Ulcerative colitis (UC) is associated with changed dietary habits and mainly linked with the gut microbiota dysbiosis, necroptosis of epithelial cells, and mucosal ulcerations. Liver dysfunction and abnormal level of liver metabolism indices were identified in UC patients, suggesting a close interaction between gut and liver disorders. Methionine-choline deficient diet (MCD) has been shown to induce persistent alterations of gut microbiota and metabolome during hepatitis. In this study we further explored the disease phenotypes in UC patients and investigated whether MCD functioned as a trigger for UC susceptibility. After assessing 88 serum specimens from UC patients, we found significant liver dysfunction and dyslipidemia including abnormal ALT, AST, TG, TC, LDL-c and HDL-c. Liver dysfunction and dyslipidemia were confirmed in DSS-induced colitis mice. We fed mice with MCD for 14 days to cause mild liver damage, and then treated with DSS for 7 days. We found that MCD intake significantly exacerbated the pathogenesis of mucosal inflammation in DSS-induced acute, progressive, and chronic colitis, referring to promotion of mucosal ulcers, colon shortening, diarrhea, inflammatory immune cell infiltration, cytokines release, and abnormal activation of inflammatory macrophages in colon and liver specimens. Intraperitoneal injection of clodronate liposomes to globally delete macrophages dramatically compromised the pathogenesis of MCD-triggering colitis. In addition, MCD intake markedly changed the production pattern of short-chain fatty acids (SCFAs) in murine stools, colons, and livers. We demonstrated that MCD-induced colitis pathogenesis largely depended on the gut microbes and the disease phenotypes could be transmissible through fecal microbiota transplantation (FMT). In conclusion, this study supports the concept that intake of MCD predisposes to experimental colitis and enhances its pathogenesis via modulating gut microbes and macrophages in mice.