Hon Wai Koon, PhD

Assistant Professor, Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at UCLA

Dr. Koon’s research is focused on the synthesis, mechanism of action and roles of the antimicrobial peptide cathelicidin in inflammatory bowel disease, intestinal infection and colon cancer. Cathelicidin is a natural endogenous anti-microbial peptide that is protective to the host as a part of the innate immune system. Dr Koon initially showed the bacterial DNA, as toll-like receptor 9 ligand, can increase cathelicidin LL-37 expression in monocytes. He also demonstrated increased expression of LL-37 in monocytes/macrophages in the colonic mucosa of ulcerative colitis patients. Endogenous cathelicidin ameliorates DSS colitis via bone marrow derived immune cells. Moreover, Toxin A from Clostridium difficile can induce LL-37 expression in human colonic epithelial cells (NCM460). Mouse cathelicidin knockout mice develop more severe intestinal inflammation than wild-type mice. Therefore, we understand that endogenous cathelicidin is likely to mobilize a protective response to intestinal infection and inflammation. We are continuing to study the expression mechanism of endogenous cathelicidin in the gastrointestinal tract. We also found that exogenous cathelicidin has profound protective effects in acute and chronic intestinal inflammation. Cathelicidin mediates various anti-inflammatory signaling pathways that promote healing of intestinal mucosa.  Detailed mechanisms are still being investigated. This involves the coordination of epithelial, endothelial and immune systems in the intestine and establishes a new direction of research in digestive diseases across various functional systems in body.  Dr. Koon has been  awarded a Pilot and Feasibility Study Grant from the CURE: DDRCC to investigate the anti-inflammatory mechanisms of  cathelicidin peptides in acute and chronic colitis.


Hon Wai Koon
UCLA Medicine-Digestive Diseases
BOX 957019, Inflammatory Bowel Disease Center, 675 Charles E. Young Dr. South
Los Angeles, CA 90095-7019