Defining Stat3 Antimicrobial Mechanisms in Human Urothelium

Research Inst Nationwide Children'S Hosp, Columbus OH

Investigators

Abstract

PROJECT SUMMARY/ABSTRACT Urinary tract infections (UTI) are a morbid condition affecting a significant proportion of individuals; yet there has been minimal progress made in their treatment and even prevention beyond antibiotic use. The host-pathogen interaction is an important relationship in UTI pathogenesis and interventions promoting the host innate immune response to reduce UTI susceptibility would be ideal therapeutic measures. The urothelium serves essential roles in the detection and elimination of invading bacteria through expression of bacterial receptors, production of cytokines and chemokines, and secretion of antimicrobial peptides (AMPs). We have previously demonstrated in a murine model of UTI that the interleukin (IL)-6/Signal Transducer and Activator of Transcription (STAT) 3 signaling pathway in the urothelium is important in producing AMPs and eliminating uropathogenic Escherichia coli (UPEC) from the urinary tract. While the transcription factor STAT3 is a central mediator in this process, its contributions to urothelial antimicrobial properties and transcriptional targets are incompletely understood. The objective of this proposal is to define STAT3 mediated host defense mechanisms in human urothelium. This proposal tests the hypothesis that STAT3 and its downstream targets contribute to UTI defense by limiting intracellular and extracellular bacteria urothelial reservoirs necessary for UTI pathogenesis, with the goal that these host mediators could be leveraged in treating and preventing UTI. The novelty of this proposal is the use of CRISPR/Cas9 gene editing in human urothelial cells to study STAT3 biology and the use of RNA-seq to reveal transcriptional targets of STAT3 signaling. The anticipated outcome of this research is to identify the mechanisms by which STAT3 confers host immunity against UTI and reveal its therapeutic targets. Aim 1 will define mechanisms by which STAT3 mediates urothelial defense against UTI in human urothelial cell culture. Aim 2 will identify transcriptional targets of STAT3 that serve instrumental roles in limiting UTI. Together, these Aims seek to implicate STAT3 and its downstream targets as integral components of the host innate immune response to UTI. The completion of this award will broaden our understanding of the mechanisms by which STAT3 signaling impacts UTI and provide candidate transcriptional targets which would be further interrogated in an R01 application.