Urinary tract infections (UTIs) afflict approximately 7 million women in the U.S. annually, causing significant morbidity and costing $3.5 billion for treatment. Most community-acquired UTIs are due to infection by uropathogenic E. coli (UPEC) that elicit an inflammatory response in the bladder during acute cystitis. Identifying novel therapeutic targets against UPEC is critical because of both the high incidence of UTIs and the increasing prevalence of antimicrobial resistance among UPEC isolates. NF:B is a pivotal mediator of inflammation and other innate responses, so we previously examined urothelial NF:B responses to UPEC and demonstrated that UPEC possess NF:B suppressive activity (NSA). To characterize the molecular basis of NSA, we performed a genetic screen and identified NSA mutants in UPEC that enhance urothelial inflammation, increase apoptosis, and exhibited attenuated intracellular proliferation. The NSA mutants are defective for activities of normal surface structure biosynthesis, and the involved surface structures are potential activators of innate host responses through Toll-like receptors (TLRs). TLR signaling includes the I:B kinase complex (IKK), where other receptor signals converge with TLR signals that activate NF:B, such as signals induced by EGF and TNF. Since UPEC also modulates EGF and TNF signaling, we hypothesize that UPEC modulation of innate responses by NSA is mediated by bacterial macromolecules that differentially induce TLR signals impinging upon IKK, thus altering key events of UTI pathogenesis that can be exploited to develop novel therapies. Indeed, NSA mutants modulate I:B phosphorylation, induce elevated urothelial apoptosis, are defective for intracellular proliferation, and stimulate enhanced protection in a UTI vaccine assay.
In Aim 1, we will identify the UPEC molecules(s) mediating NSA.
In Aim 2, we will identify the urothelial targets of UPEC NSA.
In Aim 3, we will quantify the impact of NSA on UPEC-induced apoptosis and UPEC invasion and intracellular proliferation.
In Aim 4, we will determine the therapeutic potential of UPEC NSA mutants as live vaccines. For all aims, we will employ UPEC strain NU14 and isogenic mutants that differentially induce host responses, and we will use both human cell culture and murine UTI models. These studies lay the groundwork for development and optimization of novel and effective live attenuated vaccines for UTI.
Urinary tract infections afflict approximately 7 million women in the U.S. annually. The bacteria that cause the majority of infections, uropathogenic Escherichia coli (UPEC), modify the responses of bladder tissues to promote successful infection. This project will define the mechanism that UPEC uses to modify the host responses and thus provides the groundwork for development and optimization of novel, live-attenuated vaccines against urinary tract infection.
|Thumbikat, Praveen; Berry, Ruth E; Zhou, Ge et al. (2009) Bacteria-induced uroplakin signaling mediates bladder response to infection. PLoS Pathog 5:e1000415|
|Thumbikat, Praveen; Berry, Ruth E; Schaeffer, Anthony J et al. (2009) Differentiation-induced uroplakin III expression promotes urothelial cell death in response to uropathogenic E. coli. Microbes Infect 11:57-65|
|Schaeffer, A J (2001) What do we know about the urinary tract infection-prone individual? J Infect Dis 183 Suppl 1:S66-9|
|Navas-Nacher, E L; Dardick, F; Venegas, M F et al. (2001) Relatedness of Escherichia coli colonizing women longitudinally. Mol Urol 5:31-6|
|Schoor, R A; Anderson, B; Klumpp, D J et al. (2001) Secretory IGA differentially promotes adherence of type 1-piliated Escherichia coli to immortalized vaginal epithelial cell lines. Urology 57:556-61|
|Rajan, N; Pruden, D L; Kaznari, H et al. (2000) Characterization of an immortalized human vaginal epithelial cell line. J Urol 163:616-22|
|Rajan, N; Cao, Q; Anderson, B E et al. (1999) Roles of glycoproteins and oligosaccharides found in human vaginal fluid in bacterial adherence. Infect Immun 67:5027-32|
|Schaeffer, A J; Rajan, N; Wright, E T et al. (1999) Role of vaginal colonization in urinary tract infections (UTIs). Adv Exp Med Biol 462:339-49|
|Venegas, M F; Navas, E L; Gaffney, R A et al. (1995) Binding of type 1-piliated Escherichia coli to vaginal mucus. Infect Immun 63:416-22|
|Gaffney, R A; Venegas, M F; Kanerva, C et al. (1995) Effect of vaginal fluid on adherence of type 1 piliated Escherichia coli to epithelial cells. J Infect Dis 172:1528-35|
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