MP24-06 IN VIVO ROLE OF NLRP3 INFLAMMASOME IN INNATE UROTHELIAL DEFENSES AGAINST UROPATHOGENIC E. COLI

Abstract

You have accessJournal of UrologyInfections/Inflammation/Cystic Disease of the Genitourinary Tract: Kidney & Bladder I1 Apr 2016MP24-06 IN VIVO ROLE OF NLRP3 INFLAMMASOME IN INNATE UROTHELIAL DEFENSES AGAINST UROPATHOGENIC E. COLI Yan Liu, Feng He, Ellen Shapiro, Herbert Lepor, and Xue-Ru Wu Yan LiuYan Liu More articles by this author , Feng HeFeng He More articles by this author , Ellen ShapiroEllen Shapiro More articles by this author , Herbert LeporHerbert Lepor More articles by this author , and Xue-Ru WuXue-Ru Wu More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.762AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The NLRP3 inflammasome is a multi-protein complex consisting of a pattern recognition receptor (NLRP3), an adaptor (ASC) and caspase 1. It is a critical integrator of innate host defenses in myeloid and non-myeloid cells by promoting the maturation of proinflammatory cytokines such as interleukin 1beta and 18. To date, no study has been reported regarding the in vivo role of NLRP3 inflammasome in urinary tract infection (UTI) caused by uropathogenic E. coli (UPEC). METHODS Experimental bladder infection was elicited in wild-type female mice through transurethral inoculation of clinical cystitis isolates, UTI89 and NU14. Formation of speck in urothelium, urine IL 1beta and cleaved caspase 1 in urothelium, hallmarks of NLRP3 inflammasome activation, were determined using immunofluorescence staining, ELISA and Western blotting, respectively. Studies were extended into NLRP3 and caspase 1 knockout (KO) mice, using UPEC strains as well as E. coli strains isolated from human asymptomatic bacteriuria (ABU; ABU83972 and ABU35) and recurrent UTI (C055 and C001). Additionally, Toll-like receptor 4 (TLR4) KO mice were analyzed to ascertain whether TLR4 status affects NLRP3 inflammasome activation. RESULTS Transurethral inoculation of UPEC strains UTI89 and NU14, but not laboratory strain AAEC191A or FimH-deletion strain NU14-1, led to urothelial speck formation, increased urine IL 1beta secretion and urothelial pro-caspase 1 cleavage. These three NLRP3 inflammasome activation markers peaked by 6 hours and subsided by 12 hours after UPEC inoculation. Such responses were significantly blunted in NLRP3 KO mice and even more so in caspase 1 KO mice. The decreased NLRP3 inflammasome response in these KO mice inversely correlated with significantly increased UPEC retention in the bladder. Whereas the two ABU strains elicited only 1/5 of urinary IL 1beta in wild-type mice, compared with the UPEC strains, the two strains from recurrent UTI elicited as much IL 1beta response as the two cystitis strains. Finally, markedly decreased IL 1beta production and secretion by urothelium was observed in TLR4 KO mice compared with wild-type mice, suggesting that lipopolysaccharide/TLR4 interaction is crucial for NLRP3 inflammasome activation in the urothelium. CONCLUSIONS Our data demonstrate for the first time that UPEC can activate inflammasomes in the urothelial cells via the NLRP3 pathway and suggest that reduced activity of this signaling pathway may predispose the urinary tract to recurrent infections by uropathogenic E. coli. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e272 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Yan Liu More articles by this author Feng He More articles by this author Ellen Shapiro More articles by this author Herbert Lepor More articles by this author Xue-Ru Wu More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...