Translocation of Viable Gut Microbiota to Mesenteric Adipose Drives Formation of Creeping Fat in Humans
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ABSTRACT: A mysterious feature of Crohn’s disease (CD) is the extra-intestinal manifestation of "creeping fat" (CrF), defined as expansion of mesenteric adipose tissue around the inflamed and fibrotic intestine. In the current study, we explored whether microbial translocation in human intestinal inflammation serves as a central cue for CrF development. We discovered a subset of mucosal-associated gut bacteria that consistently translocated and remained viable in CrF in CD ileal surgical resections. We identified Clostridium innocuum as a signature of this consortium with strain variation between the mucosa and adipose. Single-cell RNA sequencing characterized CrF as both pro-fibrotic and pro-adipogenic with a rich milieu of activated immune cells responding to microbial stimuli, which we confirm in gnotobiotic mice colonized with C. innocuum. Ex vivo validation of expression patterns suggests C. innocuum stimulates tissue remodeling via M2 macrophages leading to an adipose tissue barrier that prevents further dissemination of bacteria.
Project description:A feature of Crohn's disease is the extra-intestinal manifestation of creeping fat, defined as expansion of mesenteric adipose tissue around the inflamed and fibrotic ileum. In comparison to healthy controls, we found that the greatest transcriptional changes in creeping fat are functions related to immune response to bacterial products.
Project description:As a hallmark of Crohn's disease (CD),creeping fat (CF) is intimately related to intestinal fibrosis and postoperative recurrence. It is defined as expansion of mesenteric adipose tissue envelops the diseased intestinal segment. Compared with the healthy controls, CF has enriched functions related to adipogenesis and immune response.
Project description:Creeping fat, also known as mesenteric fat, which is connected to the inflamed segments of the intestine and is a hallmark of Crohn's disease (CD), appears to be correlated with disease activity. Adipose-stem cells isolated from the creeping fat of CD subjects were found to be dysfunctional (exhibiting a high inflammatory profile, high invasive and phagocytic capacities, and worse immunosuppressive properties), and this dysfunction persisted in hASCs taken from CD subjects who were in remission of the disease. We hypothesized that the abnormal behavior of adipose stem cells is caused by the accumulation of epigenetic modifications due to the inflammatory environment underlying active CD. DNA methylation and transcriptomics were performed in adipose-derived stem cells (ASCs) isolated from visceral adipose tissue biopsies of active and inactive CD patients and non-IBD patients. An integrative analysis of both omics was performed to obtain the best gene candidates.
Project description:Creeping fat, also known as mesenteric fat, which is connected to the inflamed segments of the intestine and is a hallmark of Crohn's disease (CD), appears to be correlated with disease activity. Adipose-stem cells isolated from the creeping fat of CD subjects were found to be dysfunctional (exhibiting a high inflammatory profile, high invasive and phagocytic capacities, and worse immunosuppressive properties), and this dysfunction persisted in hASCs taken from CD subjects who were in remission of the disease. We hypothesized that the abnormal behavior of adipose stem cells is caused by the accumulation of epigenetic modifications due to the inflammatory environment underlying active CD. DNA methylation and transcriptomics were performed in adipose-derived stem cells (ASCs) isolated from visceral adipose tissue biopsies of active and inactive CD patients and non-IBD patients. An integrative analysis of both omics was performed to obtain the best gene candidates.
Project description:Our hypothesis is that in IBD patients intestinal bacteria translocation into the intra-abdominal fat depots affects adipocyte morphology and gene expression. The study aimed to study adipocyte gene expression of omental (OM) and mesenteric (MES) adipose tissue of ulcerative colitis (UC) and crohn's disease (CD). Total RNA was extracted from isolated adipocytes from omental and mesenteric adipose tissue of CD and UC patients. Microarray experiments were performed in duplicates of 4 different pools of RNAs extracted from adipocytes isolated from OM and MES of UC patients (n=5) and CD patients (n=5) respectively.
Project description:Our hypothesis is that in IBD patients intestinal bacteria translocation into the intra-abdominal fat depots affects adipocyte morphology and gene expression. The study aimed to study adipocyte gene expression of omental (OM) and mesenteric (MES) adipose tissue of ulcerative colitis (UC) and crohn's disease (CD).
Project description:In Crohn's disease, creeping fat is the characteristic expansion of mesenteric adipose tissue wrapping around the inflamed intestine. Through a comparative transcriptomic analysis of creeping fat and normal-looking mesenteric adipose tissues from patients with Crohn's disease and non-Crohn's disease, we found that a dynamic transcriptional and cell compositional change occurs during the progression from non-Crohn's disease to Crohn's disease, and finally to creeping fat.
Project description:Tissue fibrosis is a serious complication of Crohnâs disease (CD) as well as of a variety of other complex, chronic pathologies. Understanding the underlying pathophysiology of tissue fibrosis is crucial for the development of tissue-specific prevention and interventional treatment strategies. To identify molecular states specific to fibrotic disease, we employed deep sequencing to define the genome-wide DNA methylome and the whole transcriptome of purified human intestinal fibrotic fibroblasts (HIFs) isolated from the colon of patients with fibrotic CD. Integration of this information, via computational tools, identified candidate molecular interactions that could lead to fibrosis pathology. Our definition of a genome-wide fibrosis-specific DNA methylome provides a new paradigm for understanding mechanisms of pathological gene expression that lead to intestinal fibrosis and may have relevance to fibrogenesis in other organs. Human intestinal fibroblasts (HIFs) were extracted and cultured from colon specimens of two groups: Crohnâs disease with associated fibrosis (n=3) and normal fibroblasts from patients with Diverticulitis (n=3). Both RNA-seq and MBD-isolated genome sequencing (MiGS) were performed on every sample.
Project description:Background and aims: Intestinal fibrosis is a common complication of Crohn’s disease (CD). It is characterised by an excessive accumulation of fibroblasts differentiating into activated myofibroblasts secreting excessive extracellular matrix. The potential role of the intestinal epithelium in this fibrotic process remains poorly defined. Methods: A total of 113 CD and control subjects were studied. We performed a pilot proteomic study comparing the proteome of surface epithelium isolated by laser capture microdissection in normal and fibrotic zones of resected ileal CD strictures (n=5). Selected proteins were validated by immunohistochemistry (IHC) in colonic and ileal samples of stricturing CD patients (n=44), pure inflammatory CD (n=29) and control subjects (n=40). Functional assays with cell lines cultures and a fibroblast to myofibroblast differentiation model were used to assess the role of the highlighted epithelial proteins in CD fibrosis. Results: Proteomic study revealed an endoplasmic reticulum (ER) stress and unfolded protein response (UPR) markers increase in the epithelium overlying ileal fibrotic strictures, involving Anterior gradient protein 2 homolog (AGR2) and Binding immunoglobulin protein (BiP). This was confirmed by IHC. The ER stress induction in intestinal epithelial cells increased AGR2 as well as BiP expression and led to an extracellular secreted AGR2. A fibroblast to myofibroblast differentiation was obtained with the supernatant of intestinal epithelial cells pre-conditioned by ER stress and with recombinant AGR2. Conclusions: AGR2 and other ER stress markers are increased within the intestinal epithelium overlying fibrotic strictures and might contribute to profibrotic signals involved in CD fibrosis.
2022-04-04 | PXD022214 | Pride
Project description:Microbial diversity in human creeping fat, mesenteric adipose tissue and underlying intestinal mucosa