Coordinated stationary phase control of Campylobacter motility and biofilm

Project: Research project

Description

ABSTRACT Campylobacter jejuni is a primary bacterial cause of gastroenteritis in the United States, with at least 2
million cases of C. jejuni gastroenteritis each year in the U.S. (an incidence equal or greater to that of
Salmonella and Shigella combined). C. jejuni is responsible for sporadic disease as well as food-borne / water-
borne outbreaks, which result from contaminated food and exposure to recreational waters. Some C. jejuni
infections lead to the development of Guillain-Barr¿ Syndrome, the leading cause of acute paralysis in the
world. Despite the high prevalence of Campylobacter disease and more than 20 years of study, the
mechanisms by which C. jejuni causes disease remain incompletely understood and severely understudied. In many bacteria, CsrA regulates numerous important phenotypes, including virulence, carbon metabolism,
motility, quorum sensing, biofilm production, and animal colonization. While in all Gram-negative bacteria
studied to date CsrA activity is controlled by inducible small regulatory RNAs (sRNAs), new data suggests for
the first time that C. jejuni CsrA is regulated by novel protein-protein interactions with FliW, a member of the
flagellar biosynthesis pathway, thus linking the synthesis of the critical virulence factors flagella to the
regulation of other stationary phase cell processes such as biofilm formation. We constructed a C. jejuni
mutant lacking csrA, and have shown that the csrA mutant exhibits pleiotropic virulence-related phenotypes
including decreased motility, epithelial cell adherence, biofilm formation, resistance to oxidative stress, and
colonization of mice. Conversely, the csrA mutant shows increased invasion of human epithelial cells. This
underscores the importance of the CsrA regulon in C. jejuni pathogenesis. We have determined the
presumptive CsrA regulon, and it contains a number of proteins with clear links to flagellar motility / chemotaxis
and to stationary phase processes such as biofilm formation and acetate metabolism. Finally, we have
demonstrated direct interaction of FliW with CsrA, supporting the link between flagella and CsrA regulation. Overall hypothesis: C. jejuni CsrA plays an important role in the pathogenesis of C. jejuni via stationary
phase, post-transcriptional regulation of virulence / survival properties including motility and biofilm formation. We propose a detailed study of CsrA-mediated post-transcriptional stationary phase gene regulation in C.
jejuni, focusing on the mechanism by which CsrA controls the expression of motility and biofilm formation. We
will use genetic, proteomic and biochemical approaches to achieve the goals outlined in these two specific
aims: Aim 1) Define the roles of CsrA, FliW, and FlaA in coordinating stationary phase regulation of motility and
chemotaxis, and Aim 2) Define the role of CsrA in regulating biofilm production and acetate metabolism.
StatusFinished
Effective start/end date12/1/1311/30/18

Funding

  • National Institutes of Health: $300,000.00
  • National Institutes of Health: $336,957.00
  • National Institutes of Health: $336,957.00

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Campylobacter jejuni
Campylobacter
Biofilms
Virulence
Regulon
Flagella
Gastroenteritis
Acetates
Epithelial Cells
Food
Quorum Sensing
Proteins
Shigella
Water
Virulence Factors
Paralysis
Proteomics
Disease Outbreaks
Molecular Biology
Phenotype

ASJC

  • Medicine(all)
  • Immunology and Microbiology(all)