Novel Virulence Strategies of Enteropathogenic Escherichia Coli: An Integrated Study

Abstract

Enteropathogenic Escherichia coli (EPEC) is a Gram-negative bacteria responsible for significant morbidity and mortality in young children. EPEC elaborates a type III secretion system (T3SS), which translocates bacterial effector proteins into the host intestinal epithelial cell. To this date, 23 effector proteins are known to be secreted by EPEC. Over the past two decades, traditional studies uncovered the functions of some of these effector proteins. While there was an initial rise in the EPEC effector function discoveries, we now observe a plateau in the identification of host-EPEC interactions. Thus, the aim of my dissertation is to define novel virulence strategies in EPEC pathogenesis, and to demonstrate how traditional reductionist and global systems biology approaches can be utilized in uncovering functions of individual effectors, as well as the complex interplay of effectors in modulating host functions. Specifically, we defined the novel cytoprotective function of a T3SS effector EspZ. We further illustrated the complex interplay of EPEC effectors by defining how EPEC utilizes EspZ and EspF to dynamically regulate the prosurvival epidermal growth factor receptor signaling pathway. Finally, by integrating comparative proteomics and traditional reductionist approaches, we identified a novel function for EspH, and defined the mechanism by which EspH perturbs epithelial cell structure and function.