Pseudomonas aeruginosa infections result in significant morbidity and mortality in people suffering from cystic fibrosis (CF). A key feature of these infections is that they involve biofilm communities. Another is that during the course of chronic infection, P. aeruginosa acquires mutations that help it adapt to the CF environment. This proposal will investigate a clear link between biofilm formation and genetic adaptation, the RSCV phenotype. RSCVs generally exhibit increased biofilm formation and antimicrobial tolerance relative to the non- mucoid, smooth colony morphotype. One important trait of RSCVs are elevated production of the biofilm matrix exopolysaccharide PEL. The structure of PEL remains unknown, and its elucidation is a goal of this proposal. In addition, P. aeruginosa RSCVs are actively selected for during the course of chronic cystic fibrosis (CF) airway infections. We recently discovered that the prevalence of RSCVs in the CF airways has been grossly underestimated and we subsequently identified novel genetic loci linked to the RSCV phenotype. The molecular mechanism underpinning why these mutations produce RSCVs is unclear. Finally, we found that RSCVs can be highly variable phenotypically, depending upon the causal mutation. Some of these variable phenotypes are pathogenically relevant, suggesting that different RSCVs may vary in their ability to form biofilms and cause chronic infection. The overall goals of this application are to determine the structure of PEL and to elucidate the molecular mechanism leading to the RSCV phenotype that results from novel RSCV- linked mutations. We will also examine the pathogenic fitness advantages of different RSCV genotypes using chronic animal models of infection and in vitro cellular immunological assays. Once mucoid genetic variants of P. aeruginosa emerge, prognosis of CF patients clearly worsens. Thus, there exists a critical window of opportunity for immunological or chemotherapeutic intervention prior to mucoid conversion. RSCVs are usually observed prior to mucoidy, thus therapeutic strategies taking advantage of this window of opportunity would have to account for them. A thorough analysis of RSCVs and Pel may lead to the development of therapeutic agents and improve the quality of life for CF patients as well as individuals with other P. aeruginosa infections that involve biofilms.

Public Health Relevance

This proposal is focused on examining the role of RSCVs in Pseudomonas aeruginosa biofilm formation and pathogenesis as it relates to cystic fibrosis infection. There exists a critical window of opportunity for immunological or chemotherapeutic intervention in CF prior to mucoid conversion. RSCVs are usually observed prior to mucoidy, thus therapeutic strategies taking advantage of this window of opportunity would have to account for them.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI077628-08
Application #
9293960
Study Section
Bacterial Pathogenesis Study Section (BACP)
Program Officer
Lu, Kristina
Project Start
2009-07-17
Project End
2019-06-30
Budget Start
2017-07-01
Budget End
2018-06-30
Support Year
8
Fiscal Year
2017
Total Cost
Indirect Cost
Name
University of Washington
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
605799469
City
Seattle
State
WA
Country
United States
Zip Code
98195
Pestrak, Matthew J; Chaney, Sarah B; Eggleston, Heather C et al. (2018) Pseudomonas aeruginosa rugose small-colony variants evade host clearance, are hyper-inflammatory, and persist in multiple host environments. PLoS Pathog 14:e1006842
Tseng, Boo Shan; Reichhardt, Courtney; Merrihew, Gennifer E et al. (2018) A Biofilm Matrix-Associated Protease Inhibitor Protects Pseudomonas aeruginosa from Proteolytic Attack. MBio 9:
Reichhardt, Courtney; Wong, Cynthis; Passos da Silva, Daniel et al. (2018) CdrA Interactions within the Pseudomonas aeruginosa Biofilm Matrix Safeguard It from Proteolysis and Promote Cellular Packing. MBio 9:
Armbruster, Catherine R; Parsek, Matthew R (2018) New insight into the early stages of biofilm formation. Proc Natl Acad Sci U S A 115:4317-4319
Malhotra, Sankalp; Limoli, Dominique H; English, Anthony E et al. (2018) Mixed Communities of Mucoid and Nonmucoid Pseudomonas aeruginosa Exhibit Enhanced Resistance to Host Antimicrobials. MBio 9:
Marmont, Lindsey S; Rich, Jacquelyn D; Whitney, John C et al. (2017) Oligomeric lipoprotein PelC guides Pel polysaccharide export across the outer membrane of Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 114:2892-2897
Amoh, Takashi; Murakami, Keiji; Kariyama, Reiko et al. (2017) Effects of an autoinducer analogue on antibiotic tolerance in Pseudomonas aeruginosa. J Antimicrob Chemother 72:2230-2240
Passos da Silva, Daniel; Schofield, Melissa C; Parsek, Matthew R et al. (2017) An Update on the Sociomicrobiology of Quorum Sensing in Gram-Negative Biofilm Development. Pathogens 6:
Snarr, Brendan D; Baker, Perrin; Bamford, Natalie C et al. (2017) Microbial glycoside hydrolases as antibiofilm agents with cross-kingdom activity. Proc Natl Acad Sci U S A 114:7124-7129
Marmont, Lindsey S; Whitfield, Gregory B; Rich, Jacquelyn D et al. (2017) PelA and PelB proteins form a modification and secretion complex essential for Pel polysaccharide-dependent biofilm formation in Pseudomonas aeruginosa. J Biol Chem 292:19411-19422

Showing the most recent 10 out of 33 publications