Project description:Many previous studies had revealed that gastrointestinal microbiome is changed compositionally and ecologically in patients with colorectal cancer comparing with healthy population. These finding provide us with a new sight to take advantage of gut microbiota. The current study aims to explore new potential biomarkers for early screening and prognostic prediction of colorectal cancer and colorectal polyps by analyzing metagenomics and metabolomics of gut microbiota.
Project description:By fermenting dietary fiber, the gut microbiota supplies carbon to host epithelial cells in the form of short-chain fatty acids and other metabolic byproducts. To track the transfer of carbon from fiber to host tissues via the microbiota and more clearly define the molecules mediating this transfer, we conducted stable isotope tracing in mice with U-13C-labeled inulin followed by untargeted metabolomics by LC-MS. Additionally, we applied this labeling approach to mice with chemically induced colitis to examine how inflammation impacts carbon transfer from the microbiota to host tissues, which may aid in understanding the development of inflammatory bowel diseases.
Project description:Rationale: Physical exercise is essential for skeletal integrity and bone health. The gut microbiome, as a pivotal modulator of overall physiologic states, is closely associated with skeletal homeostasis and bone metabolism. However, the potential role of intestinal microbiota in the exercise-mediated bone gain remains unclear. Methods: We conducted microbiota depletion and fecal microbiota transplantation (FMT) in ovariectomy (OVX) mice and aged mice to investigate whether the transfer of gut ecological traits could confer the exercise-induced bone protective effects. The study analyzed the gut microbiota and metabolic profiles via 16S rRNA gene sequencing and LC-MS untargeted metabolomics to identify key microbial communities and metabolites responsible for bone protection. Transcriptome sequencing and RNA interference were employed to explore the molecular mechanisms. Results: We found that gut microbiota depletion hindered the osteogenic benefits of exercise, and FMT from exercised osteoporotic mice effectively mitigated osteopenia. Comprehensive profiling of the microbiome and metabolome revealed that the exercise-matched FMT reshaped intestinal microecology and metabolic landscape. Notably, alterations in bile acid metabolism, specifically the enrichment of taurine and ursodeoxycholic acid, mediated the protective effects on bone mass. Mechanistically, FMT from exercised mice activated the apelin signaling pathway and restored the bone-fat balance in recipient MSCs. Conclusion: Our study underscored the important role of the microbiota-metabolic axis in the exercise-mediated bone gain, heralding a potential breakthrough in the treatment of osteoporosis.
Project description:Ulcerative colitis (UC), belonging to inflammatory bowel disease (IBD), is a chronic and relapsing inflammatory disorders of the gastrointestinal tract, which is not completely cured so far. Valeriana jatamansi is a Chinese medicine used clinically to treat "diarrhea", which is closely related to UC. This study was to elucidate the therapeutic effects of V. jatamansi extract (VJE) on dextran sodium sulfate (DSS)-induced UC in mice and its underlying mechanism. In this work, VJE effectively ameliorate the symptoms, histopathological scores and reduce the production of inflammatory factors of UC mice. The colon untargeted metabolomics analysis and 16S rDNA sequencing showed remarkable differences in colon metabolite profiles and intestinal microbiome composition between the control and DSS groups, and VJE intervention can reduce these differences. Thirty-two biomarkers were found and modulated the primary pathways including pyrimidine metabolism, arginine biosynthesis and glutathione metabolism. Meanwhile, twelve significant taxa of gut microbiota were found. Moreover, there is a close relationship between endogenous metabolites and intestinal flora. These findings suggested that VJE ameliorates UC by inhibiting inflammatory factors, recovering intestinal maladjustment, and regulating the interaction between intestinal microbiota and host metabolites. Therefore, the intervention of V. jatamansi is a potential therapeutic treatment for UC.
Project description:Urolithin A is a polyphenol derived from the multi-step metabolism of dietary ellagitannins by the human gut microbiota which can affect host health. Most, but not all, individuals harbor a microbiota capable of urolithin A production; however, the enzymes that dehydroxylate its dietary precursor, urolithin C, are unknown. Here, we used a combination of transcriptomics and proteomics to reveal a urolithin C dehydroxylase (ucd) operon that dehydroxylates 9-hydroxy urolithin compounds in Enterocloster spp. Using comparative genomics, we identified Lachnoclostridium pacaense as a novel urolithin C metabolizer. Biochemical characterization and structure predictions of proteins in the Ucd complex demonstrated that dehydroxylation was both NADH- and molybdopterin-dependent and used urolithin C as a terminal electron acceptor. A meta-analysis publicly available metagenomic data revealed that both bacteria and ucd operon genes are widely distributed in gut metagenomes and likely comprise keystone species in the metabolism of urolithins by the human gut microbiota.