Infections by Gram-positive bacteria cause tens of thousands of deaths in the United States each year. The transcriptional regulator catabolite control protein A (CcpA) has recently been found to influence the virulence gene expression profile during growth in standard laboratory medium of numerous Gram-positive pathogens including group A Streptococcus (GAS). CcpA was originally identified in Bacillus species where it binds DNA sequences termed catabolite response element (cre) sites in conjunction with its co-factor histidine-containing phosphoprotein phosphorylated at serine residue 46 (HPr-Ser46-P). Orthologues of CcpA, HPr, and the kinase/phosphorylase that regulates HPr phosphorlyation status (HPrK/P) are present in all major Gram- positive human pathogens, and there are accumulating data suggesting that the CcpA-(HPr-Ser46-P)-HPrK/P axis contributes to the infectivity of diverse bacterial species. The long term goals of this project are to clearly define how the CcpA-(HPr-Ser46-P)-HPrK/P axis contributes to GAS virulence and to ascertain mechanisms by which CcpA influences gene expression during infection.
The specific aims of this proposal have been designed to test hypotheses arising from preliminary data demonstrating that: 1) Inactivation of CcpA altered GAS gene expression during infection in mouse muscle;2) Inactivation of CcpA decreased GAS virulence in a mouse myositis model;3) Mutation of the central CpG of a GAS cre site decreased CcpA-(HPr-Ser46-P) DNA binding affinity;and 4) CcpA influenced gene expression under conditions in which HPr-Ser46-P levels are low or absent.
In aim 1, gene expression analysis of wild-type and CcpA-inactivated GAS strains will be performed in multiple mouse models of infection to test the hypothesis that CcpA is a key virulence factor regulator during GAS infection.
In aim 2, the virulence of CcpA isogenic mutant strains derived from different M protein serotype parental strains will be compared to their parental wild-type strains in various mouse models of infection to test the hypothesis that CcpA positively contributes to the infectivity of GAS strains of multiple M protein serotypes.
In aim 3, a combination of in vitro and in vivo methods will be used to test the hypothesis that the central cre site CpG is critical for the effect of CcpA on GAS gene expression.
In aim 4, the gene expression profiles of CcpA and HPr-Ser46-P inactivated strains will be compared under different metabolic conditions to test the hypothesis that CcpA can affect GAS gene expression in the absence of HPr-Ser46-P. The highly conserved nature of the CcpA-(HPr-Ser46-P)-HPrK/P axis amongst major Gram-positive bacterial pathogens means that the successful completion of the proposed research may generate new insights into disease pathogenesis that are relevant to a broad array of pathogenic bacteria. Such information could form the basis for the development of novel therapeutic or preventive interventions.

Public Health Relevance

Catabolite control protein A (CcpA) controls the production of several proteins that are critical to the ability of the bacteria group A Streptococcus (GAS) to cause serious infections such as pharyngitis, or strep throat, and necrotizing fasciitis (the flesh-eating disease). The goals of this project are to define whether inactivation of CcpA affects the ability of GAS to cause infection and to determine the mechanisms by which CcpA regulates the production of key GAS proteins in response to environmental stimuli. The generated data could form the basis for novel methods to treat a broad array of bacterial infections in humans.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI089891-04
Application #
8692634
Study Section
Bacterial Pathogenesis Study Section (BACP)
Program Officer
GU, Xin-Xing
Project Start
2011-07-15
Project End
2016-06-30
Budget Start
2014-07-01
Budget End
2015-06-30
Support Year
4
Fiscal Year
2014
Total Cost
Indirect Cost
Name
University of Texas MD Anderson Cancer Center
Department
Internal Medicine/Medicine
Type
Hospitals
DUNS #
City
Houston
State
TX
Country
United States
Zip Code
77030
Bhatti, Micah D; Kalia, Awdhesh; Sahasrabhojane, Pranoti et al. (2017) Identification and Whole Genome Sequencing of the First Case ofKosakonia radicincitansCausing a Human Bloodstream Infection. Front Microbiol 8:62
DiPippo, Adam J; Tverdek, Frank P; Tarrand, Jeffrey J et al. (2017) Daptomycin non-susceptible Enterococcus faecium in leukemia patients: Role of prior daptomycin exposure. J Infect 74:243-247
Zhu, Luchang; Olsen, Randall J; Horstmann, Nicola et al. (2016) Intergenic Variable-Number Tandem-Repeat Polymorphism Upstream of rocA Alters Toxin Production and Enhances Virulence in Streptococcus pyogenes. Infect Immun 84:2086-2093
DebRoy, Sruti; Saldaña, Miguel; Travisany, Dante et al. (2016) A Multi-Serotype Approach Clarifies the Catabolite Control Protein A Regulon in the Major Human Pathogen Group A Streptococcus. Sci Rep 6:32442
Shukla, Bhavarth S; Shelburne, Samuel; Reyes, Katherine et al. (2016) Influence of Minimum Inhibitory Concentration in Clinical Outcomes of Enterococcus faecium Bacteremia Treated With Daptomycin: Is it Time to Change the Breakpoint? Clin Infect Dis 62:1514-1520
Galloway-Peña, Jessica; Clement, Meredith E; Sharma Kuinkel, Batu K et al. (2016) Application of Whole-Genome Sequencing to an Unusual Outbreak of Invasive Group A Streptococcal Disease. Open Forum Infect Dis 3:ofw042
Shelburne, Samuel A; Ajami, Nadim J; Chibucos, Marcus C et al. (2015) Implementation of a Pan-Genomic Approach to Investigate Holobiont-Infecting Microbe Interaction: A Case Report of a Leukemic Patient with Invasive Mucormycosis. PLoS One 10:e0139851
Horstmann, Nicola; Sahasrabhojane, Pranoti; Saldaña, Miguel et al. (2015) Characterization of the effect of the histidine kinase CovS on response regulator phosphorylation in group A Streptococcus. Infect Immun 83:1068-77
Flores, Anthony R; Galloway-Peña, Jessica; Sahasrabhojane, Pranoti et al. (2015) Sequence type 1 group B Streptococcus, an emerging cause of invasive disease in adults, evolves by small genetic changes. Proc Natl Acad Sci U S A 112:6431-6
Miller, Eric W; Danger, Jessica L; Ramalinga, Anupama B et al. (2015) Regulatory rewiring confers serotype-specific hyper-virulence in the human pathogen group A Streptococcus. Mol Microbiol 98:473-89

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