Strains of uropathogenic Escherichia coli (UPEC) are the principal causative agents of urinary tract infections (UTIs), which continuously rank among the most common of infectious diseases. UPEC can invade host bladder epithelial cells and subsequently multiply, forming large intracellular inclusions that resemble biofilms. Alternately, intracellular UPEC can persist at low levels in a more quiescent, non-replicating state that may serve as a reservoir for chronic and recurrent acute UTIs. Mounting evidence indicates that UPEC entry into host cells and tissues within the urinary tract promotes bacterial persistence in the face of both innate and adaptive host defenses, as well as antibiotic treatments. Virtually all UPEC isolates encode filamentous adhesive organelles called type 1 pili. We have found that the type 1 pilus adhesin FimH can engage host 1321 integrin receptors in a non-canonical fashion and thereby activate signaling cascades that result in the actin-dependent internalization of UPEC. Our preliminary data indicate that FimH-mediated bacterial invasion of host cells is dependent upon crosstalk between the actin and microtubule cytoskeletal networks, although the nature of this crosstalk remains undefined. The entry process also requires input from clathrin and distinct clathrin-associated adaptor proteins. Clathrin is best characterized for its role in the uptake of small molecules such as growth factors, but its ability to promote internalization of much larger particles like UPEC and other invasive pathogens has only recently been appreciated and remains poorly understood. The primary objectives of this application are to define the host factors that mediate UPEC invasion of bladder epithelial cells, with a focus on the functional roles of microtubule-actin crosstalk and clathrin. The impact that host cell invasion has on the establishment and persistence of UPEC within the host will also be assessed. It is hoped that the proposed work will provide a more complete understanding of the pathogenesis of acute, recurrent, and chronic UTIs, ultimately facilitating the development of improved therapeutics for treating and preventing these exceptionally common infections.

Public Health Relevance

Urinary tract infections are among the most common of infectious diseases, representing a serious economic and medical burden worldwide. By delineating how uropathogenic bacteria colonize and persist within the host, we hope to facilitate the development of improved therapeutics.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Host Interactions with Bacterial Pathogens Study Section (HIBP)
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Korpela, Jukka K
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University of Utah
Schools of Medicine
Salt Lake City
United States
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Russell, Colin W; Fleming, Brittany A; Jost, Courtney A et al. (2018) Context-Dependent Requirements for FimH and Other Canonical Virulence Factors in Gut Colonization by Extraintestinal Pathogenic Escherichia coli. Infect Immun 86:
Russell, Colin W; Richards, Amanda C; Chang, Alexander S et al. (2017) The Rhomboid Protease GlpG Promotes the Persistence of Extraintestinal Pathogenic Escherichia coli within the Gut. Infect Immun 85:
Kjelstrup, Cecilie K; Barber, Amelia E; Norton, J Paul et al. (2017) Escherichia coli O78 isolated from septicemic lambs shows high pathogenicity in a zebrafish model. Vet Res 48:3
Erman, Andreja; Hergouth, Veronika Križan; Blango, Matthew G et al. (2017) Repeated Treatments with Chitosan in Combination with Antibiotics Completely Eradicate Uropathogenic Escherichia coli From Infected Mouse Urinary Bladders. J Infect Dis 216:375-381
Lewis, Adam J; Richards, Amanda C; Mulvey, Matthew A (2016) Invasion of Host Cells and Tissues by Uropathogenic Bacteria. Microbiol Spectr 4:
Barber, Amelia E; Norton, J Paul; Wiles, Travis J et al. (2016) Strengths and Limitations of Model Systems for the Study of Urinary Tract Infections and Related Pathologies. Microbiol Mol Biol Rev 80:351-67
Lewis, Adam J; Dhakal, Bijaya K; Liu, Ting et al. (2016) Histone Deacetylase 6 Regulates Bladder Architecture and Host Susceptibility to Uropathogenic Escherichia coli. Pathogens 5:
Barber, Amelia E; Fleming, Brittany A; Mulvey, Matthew A (2016) Similarly Lethal Strains of Extraintestinal Pathogenic Escherichia coli Trigger Markedly Diverse Host Responses in a Zebrafish Model of Sepsis. mSphere 1:
Russell, Colin W; Mulvey, Matthew A (2015) The Extraintestinal Pathogenic Escherichia coli Factor RqlI Constrains the Genotoxic Effects of the RecQ-Like Helicase RqlH. PLoS Pathog 11:e1005317
Blango, Matthew G; Ott, Elizabeth M; Erman, Andreja et al. (2014) Forced resurgence and targeting of intracellular uropathogenic Escherichia coli reservoirs. PLoS One 9:e93327

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