Jason M Ridlon

Biography

He has done his Ph.D., 2008, Virginia Commonwealth University, Richmond, VA, B.S., 2002, Bridgewater College, Bridgewater, VA. Currently he is an Assistant Professor in Department of Animal Sciences At University of Illinois.

Research Interest

Bile acids are detergent molecules that allow absorption of dietary fats and fat-soluble vitamins into the bloodstream. Bile acids are synthesized from cholesterol in the liver, secreted into the small intestine where fats are taken up, and transported back to the liver in a recycling process known as the enterohepatic circulation (EHC). The EHC is 95% efficient; however, several hundred milligrams of bile acids enters the large intestine each day where they are converted to toxic and cancer-promoting secondary bile acids by gut bacteria. Secondary bile acids promote diseases of the gastrointestinal tract such as liver and colorectal cancers, and cholesterol gallstone disease. Indeed, a major treatment strategies involves diluting out harmful secondary bile acids by giving patients a bile acid known as ursodeoxycholic acid (UDCA), a minor constituent in humans, but as its name implies makes up the lion's share of bear bile. Problematically, UDCA is converted to a secondary bile acid in the gut, reducing its efficacy. Bacteria capable of metabolizing bile acids are relegated to a small number of species of anaerobic bacteria in the genus Clostridium. A major focus of our research is working out the biochemistry and molecular biology of the pathway that leads to secondary bile acids in Clostridium scindens and related species. In particular, the rate-limiting step in the metabolism of the therapeutic compound UDCA. Furthermore, the Ridlon lab is interested in using high-throughput sequencing and metabolomics in order to understand how Clostridium scindens interacts with the host and other microbes. Bile acids have become a major topic of research recently because far from simple detergents, these molecules are now recognized as hormones regulating diverse physiological and pathophysiological processes. Clostridium scindens can thus be thought of as a hormone-producing bacterium. Indeed, its very name means "to cut", an epithet given because it is capable of "cutting" the side chain of glucocorticoids resulting in the production of androstenes. Glucocorticoids and androstene measurement in stool is the principle means of determining stress in animals important to agriculture and conservation biology. Our lab works on the biochemical pathway leading to androstenes in Clostridium scindens and how these androstenes affect human and animal well-being. Taken together, our focus is on what we term the gut "sterolbiome", the repertoire of microbial genes that metabolize host-derived, dietary, and pharmaceutical steroid molecules.