Microbiomal Mediators of TL1A-induced-Fibrosis

TL1A 诱导纤维化的微生物介质

• 批准号: 10662219
• 负责人: Noam Jacob
• 金额: --
• 依托单位: VA GREATER LOS ANGELES HEALTHCARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10662219
• 关键词: 16S ribosomal RNA sequencing; Affect; Animal Model; Bacteria; Biological Models; Clinical; Complement; Complex; Complication; Crohn' s disease; Data; Development; Disease; Disease susceptibility; Engineering; Environment; Epigenetic Process; Feces; Fibroblasts; Fibrosis; Genes; Genetic; Genetic Predisposition to Disease; Genetic Risk; Germ-Free; Haplotypes; Health; Healthcare Systems; Human; Impairment; In Vitro; Individual; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Intestinal Fibrosis; Intestines; Investigation; Link; Mediating; Mediator; Methods; Microbe; Molecular; Molecular Probes; Mucosal Immune System; Mucous Membrane; Mus; Operative Surgical Procedures; Organ; Organism; Outcome; Pathogenesis; Pathway interactions; Patients; Peripheral; Persons; Phenotype; Play; Population; Predisposition; Process; Proteins; Publishing; Rectum; Risk; Role; Series; Severities; Severity of illness; Signal Transduction; Small Intestines; Specimen; Stimulus; TNF gene; TNFSF15 gene; Testing; Therapeutic; Tissues; Transgenic Organisms; Veterans; Work; cell type; clinical phenotype; commensal bacteria; commensal microbes; cytokine; disease phenotype; effective therapy; gut inflammation; gut microbiome; gut microbiota; host microbiome; human disease; in vitro Assay; in vivo; insight; member; metabolome; metabolomics; microbial; microbiome; microbiome alteration; microbiome research; microbiota; military veteran; monocyte; mouse model; novel; outcome disparities; overexpression; preempt; profibrotic fibroblast; rectal; response; risk variant; targeted treatment; therapeutic target; translational study

ABSTRACT Inflammatory Bowel Disease (IBD) results from a series of complex interactions between susceptibility and severity genes, the environment and the mucosal immune system, presenting as clinical disease. The gut microbiome contributes to IBD; altered gut microbial composition has been demonstrated in intestinal inflammation, but few studies have examined intestinal fibrosis. A vast number of potential genetic, epigenetic and microbiotic variables contribute to the severity of IBD phenotypes. Among these, relatively clear, clinically- identifiable phenotypes are those with a distinct, severe, fibrosing Crohn’s disease presentation. The gene/protein combination of tumor necrosis factor superfamily (TNFSF) member 15 and tumor necrosis factor- like (TL) cytokine 1A (referred to as: TNFSF15/TL1A) influences the severity of inflammation and fibrosis in both animal models and human disease. My recently published findings have implicated the gut microbiome in intestinal fibrosis, and on which TL1A depends to exert its pro-fibrotic effects. The precise mechanisms and specific microbial contributors to intestinal fibrosis have yet to be elucidated, however. As fibroblasts are a predominant cell type responsible for fibrosis, the mechanisms by which TL1A and microbiota drive intestinal fibrosis likely involve direct induction of fibroblast activation, as my preliminary data demonstrates. I hypothesize that TNFSF15/TL1A plays a central role in the induction and amplification of fibrosis by altering the microbiome to enhance fibrosis-promoting microbial populations and through the direct activation of fibroblasts to express fibrosis-related factors and/or to become more susceptible to microbial stimulation. In Aim 1, I will determine whether TL1A-induced fibrosis in mouse models or TNFSF15-genetic risk in Veterans with Crohn’s disease is associated with alterations in the microbiome. I will characterize the gut microbiome as assessed by 16S rRNA sequencing of stool and tissue specimens from patients with and without TNFSF15-genetic risk. To confirm the causal efficacy of these correlated organisms, WT and TL1A-transgenic germ-free C57/BL6 mice will be colonized with the candidate bacterial consortia to evaluate for development of fibrosis in vivo. These microbiota will also be characterized using metabolomic methods to allow more specific insight into their role in disease pathogenesis. In Aim 2, I will characterize the TL1A-responsive effects and molecular mechanisms of direct bacterial products and metabolites identified in Aim 1 on fibroblasts using primary isolated fibroblasts in vitro. In Aim 3, I will determine if specific bacterial metabolites can causally mediate intestinal fibrosis in vivo using selective administration in engineered mouse models. The results of this proposed study will provide insight into the specific microbes, or their products, that drive intestinal fibrosis in concert with TL1A. If host-microbiome interactions and resulting pro-fibrotic fibroblast phenotypes can be mitigated by manipulation of TL1A or the microbiome/metabolome, intestinal fibrosis may be pre-empted in genetically susceptible individuals. These investigations may thus reveal additional downstream pathways, molecules, and potential targets for therapy.

摘要