Project description:The study of how gene expression in paneth cells changes after TNF admistration in mice were the microbiome has been depleted with broad spectrum antibiotics. The depletion of the microbiome excludes the occurence of indirect effects mediated through it by TNF on PC gene expression, only direct TNF effecs on crypt cells are measured
Project description:Broad-spectrum antibiotics are frequently prescribed to children. The period of early-childhood represents a time where the developing microbiota may be more sensitive to environmental perturbations, which thus might have long-lasting host consequences. We hypothesized that even a single early-life broad-spectrum antibiotic course at a therapeutic dose (PAT) leads to durable alterations in both the gut microbiota and host immunity. In C57BL/6 mice, a single early-life tylosin (macrolide) course markedly altered the intestinal microbiome, and affected specific intestinal T-cell populations and secretory IgA expression, but PAT-exposed adult dams had minimal immunologic alterations. No immunological effects were detected in PAT-exposed germ-free animals; indicating that microbiota are required for the observed activities. Together these results indicate the impact of a single therapeutic early-life antibiotic course altering the microbiota and modulating host immune phenotypes that persist long after exposure has ceased.
Project description:Antibiotics revolutionized medicine, however, it is now clear that broad-spectrum antibiotics alter the composition and function of the host’s microbiome. The microbiome plays a key role in human health and its perturbation is increasingly recognized as contributing to many human diseases. Wide spread broad-spectrum antibiotic use has also resulted in the emergence of multi-drug resistant pathogens, spurring development of pathogen-specific strategies such as monoclonal antibodies (mAbs) to combat bacterial infection. Not only are pathogen-specific approaches not expected to induce resistance in non-targeted bacteria, but they are hypothesized to have minimal impact on the gut microbiome. Here, we compare the effects of antibiotics, pathogen-specific mAbs or their controls (saline or c-IgG) on the gut microbiome of 7-week-old, female, C57BL/6 mice. The magnitude of change in taxonomic abundance, bacterial diversity, and bacterial metabolites including short chain fatty acids (SCFA) and bile acids in the fecal pellets from mice treated with pathogen-specific mAbs was no different from animals treated with saline or an IgG control. Conversely, dramatic changes were observed in the relative abundance, as well as alpha- and beta-diversity, of the fecal microbiome, and bacterial metabolites in the feces of all antibiotic-treated mice. Taken together, these results indicate that pathogen-specific mAbs do not alter the fecal microbiome like broad-spectrum antibiotics and may represent a safer, more targeted approach to antibacterial therapy.
Project description:The most clinically relevant risk factor for Clostridioides difficile-associated disease (CDAD) is recent antibiotic treatment. Though most broad-spectrum antibiotics significantly disrupt the structure of the gut microbiota, only particular ones increase CDAD risk, suggesting additional factors might increase the risk from certain antibiotics. Here we show that commensal-independent effects of antibiotics collectively prime an in vitro germ-free human gut for CDAD. We found a marked loss of mucosal barrier and immune function with CDAD-associated antibiotic pretreatment distinct from pretreatment with an antibiotic unassociated with CDAD, which did not reduce innate immune or mucosal barrier functions. Importantly, pretreatment with CDAD-associated antibiotics sensitized mucosal barriers to C. difficile toxin activity in primary cell-derived enteroid monolayers. These data implicate commensal-independent host changes in the increased risk of CDAD with specific antibiotics. Our findings are contrary to the previously held belief that antibiotics allow for CDAD solely through disruption of the microbiome. We anticipate this work to suggest potential avenues of research for host-directed treatment and preventive therapies for CDAD, and to impact human tissue culturing protocols.
Project description:Single nucleus RNA sequencing of mouse striatum at steady state and after exercise in mice treated and untreated with broad spectrum antibiotics.