Project description:Tandem mass spectrometry based shotgun proteomics of distal gut microbiomes is exceedingly difficult due to the inherent complexity and taxonomic diversity of the samples. We introduce two new methodologies to improve metaproteomic studies of microbiome samples. These methods include the stable isotope labeling in mammals to permit protein quantitation across the two mouse cohorts, as well as the application of activity-based probes to enrich and analyze both host and microbial proteins with specific functionalities. We used these technologies to study the microbiota from the adoptive T cell transfer mouse model of inflammatory bowel disease (IBD) and compare these samples to an isogenic control; thereby, limiting genetic and environmental variables that influence microbiome composition.
Project description:Background and Aims: The impact of cigarette smoke on inflammatory bowel disease has been established by a large number of epidemiological, clinical, and preclinical studies. Exposure to cigarette smoke is associated with a higher risk of developing Crohn’s disease but is inversely correlated with the development, disease risks, progression, and relapse rate of ulcerative colitis. Few mechanistic studies have investigated the effect of cigarette smoke on intestinal inflammation and microbial composition. Methods: Three groups of mice were exposed to three different concentrations of cigarette smoke for a total of 4 weeks, including 5 days of dextran sulfate sodium treatment to induce colitis and a 7-day recovery period. A comprehensive and integrated comparative analysis of the global colon transcriptome and microbiome, as well as classical endpoints, was performed. Results: Cigarette smoke exposure significantly decreased the severity induced colitis. Colon transcriptome analysis revealed that cigarette smoke downregulated specific pathways in a concentration-dependent manner, affecting both the inflammatory state and composition of the gut microbiome. Metagenomics analysis demonstrated that cigarette smoke can modulate dextran sulfate sodium-induced dysbiosis of specific bacterial genera, contributing to resolve the inflammation or accelerate recovery. Conclusions: Cigarette smoke alters gut microbial composition and reduces inflammatory responses in a concentration-dependent manner. The present study lays the foundation for investigating potential molecular mechanisms responsible for the attenuation of colitis by cigarette smoke.
Project description:Aging is associated with declining immunity and inflammation as well as alterations in the gut microbiome with a decrease of beneficial microbes and increase in pathogenic ones. The aim of this study was to investigate aging associated gut microbiome in relation to immunologic and metabolic profile in a non-human primate (NHP) model. 12 old (age>18 years) and 4 young (age 3-6 years) Rhesus macaques were included in this study. Immune cell subsets were characterized in PBMC by flow cytometry and plasma cytokines levels were determined by bead based multiplex cytokine analysis. Stool samples were collected by ileal loop and investigated for microbiome analysis by shotgun metagenomics. Serum, gut microbial lysate and microbe-free fecal extract were subjected to metabolomic analysis by mass-spectrometry. Our results showed that the old animals exhibited higher inflammatory biomarkers in plasma and lower CD4 T cells with altered distribution of naïve and memory T cell maturation subsets. The gut microbiome in old animals had higher abundance of Archaeal and Proteobacterial species and lower Firmicutes than the young. Significant enrichment of metabolites that contribute to inflammatory and cytotoxic pathways was observed in serum and feces of old animals compared to the young. We conclude that aging NHP undergo immunosenescence and age associated alterations in the gut microbiome that has a distinct metabolic profile.