12:00 am to 4:10 pm
“Tales from the Crypt: Membrane-active antibiotics and self-assembling peptides protect the small intestinal stem cell niche”
The Bevins Lab is focused on the role of epithelial defensins in mediating host-microbe interaction at mammalian mucosal surfaces. Epithelial defensins are fundamental effector molecules of innate immunity found throughout nature that both help defend the host from infectious disease, and help sculpt the composition of colonizing microbiota. The Bevins group is credited with the discovery of two human α-defensins, HD5 and HD6. These defensins are both highly expressed by Paneth cells, secretory cells positioned adjacent to the epithelial stem cells at the base of the crypts of the small intestine. Data from in vitro experiments and in vivo models indicate that Paneth cell α-defensins play a pivotal role in defense from food and water borne pathogens in the intestine. The mechanism by which these two α-defensins protect from enteric pathogens is quite distinct. HD5 is a potent antimicrobial that kills target microbes by membrane disruption, whereas HD6 is newly discovered to self-assemble to form fibrils and nanonets that surround and entangle bacteria (“nets”). Studies in humans suggest that reduced expression of HD5 and HD6 is a fundamental feature of inflammatory bowel disease.