Dr. Ann Stapleton is an Acting Instructor in Infectious Diseases who has completed four years of clinical and research fellowship training under the supervision of Dr. Walter E. Stamm. During her fellowship, Dr. Stapleton achieved board certification in infectious diseases and initiated research studies focusing on the pathogenesis of urinary tract infections (UTIs) in women. She has developed laboratory skills both in molecular biology and in biochemical methods of studying host glycolipid (GL) receptors on human epithelial cells. Dr. Stapleton excelled as a researcher during her fellowship period and is strongly committed to a career in basic research and academic medicine. The research and training program proposed here will allow Dr. Stapleton to develop the additional basic laboratory skills in glycolipid biochemistry that will enable her to become an independent investigator. She will be directly supervised by faculty who have extensive experience in glycolipid biochemistry (Dr. Hakomori and Nudelman) and the pathogenesis of urinary tract infections (Dr. Stamm). The extensive laboratory and clinical facilities and resources of both The Biomembrane Institute and the University of Washington will provide an excellent training environment for Dr. Stapleton. The candidate proposes to study the interactions between infecting E. coli, receptors on vaginal and uroepithelial cells and the patients' secretor status. An increased risk of recurrent UTI in women has been associated with both the nonsecretor state and with increased adherence of E. coli to uroepithelial cells from these patients. In preliminary work, she demonstrated that a radiolabelled wildtype E. coli isolate expressing the P and F adhesions specifically binds to two unique GLs in extracts of vaginal epithelial cells from nonsecretors but not secretors. These exciting results imply that nonsecretors have a genetic predisposition to recurrent UTI and suggest a specific biochemical basis for this predisposition. To confirm these findings, Dr. Stapleton has isolated and purified the GLs from urinary tract tissues. In addition, she will study vaginal epithelial cells from nonsecretors and secretors to determine the density, accessibility and binding affinity of relevant GL receptors for uropathogenic E. coli. Finally, she will also test the glycolipid binding characteristics of additional E. coli isolates with known P/F phenotypes. The results of these studies will provide important insights into the pathogenesis of UTI and may lead to the development of novel means for preventing recurrent infections.
