Abstract

Interferon (IFN)-gamma is central to immunity against Mycobacterium tuberculosis and other intracellular pathogens. Tuberculosis patients with ineffective immunity produce reduced amounts of IFN-gamma mRNA and protein in response to mycobacterial antigens, but the mechanisms underlying these abnormalities are unknown. Our preliminary data indicate that transcription factors of the cAMP response element-binding protein/activation transcription factor/activator protein-1 (CREB/ATF/AP-1) family regulate production of IFNgamma by binding to the IFN-gamma proximal promoter. Our goal is to understand the mechanisms by which CREB/ATF/AP-1 transcription factors regulate IFN-gamma production in response to M. tuberculosis.
Our specific aims are: 1. Identify transcription factors that bind to the IFN-gamma proximal promoter in vivo in CD4+ and CD8+ T-cells that respond to M. tuberculosis, using microaffinity purification and chromatin immunoprecipitation; 2. Evaluate the effects of neutralization of CREB/ATF/AP-1 and other transcription factors on M. tuberculosis-induced IFN-gamma gene expression by CD4+ and CD8+ T-cells, using intracellular antibody delivery and siRNAs to transcription factors; 3. Characterize the kinetics and protein-protein interactions of the transcriptional complex (enhanceosome) that binds to the IFN-gamma proximal promoter of CD4+ and CD8+ cells, using coimmunoprecipitation and chromatin immunoprecipitation, followed by Western blotting. 4. Understand the mechanisms that mediate aberrant expression of CREB/ATF/AP-1 transcription factors in tuberculosis patients. Transcription factor levels will be determined in PBMC T-cell subpopulations in tuberculosis patients during treatment. We will determine if exposure to immunosuppressive cytokines or to M. tuberculosis-infected macrophages affects CREB/ATF/AP-1 expression. CREB/ATF/AP-1 levels in T-cells of tuberculosis patients will be enhanced by viral expression vectors and nucleofection, and the effects on IFN-gamma production will be determined. ? ?

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI063514-03
Application #
7196490
Study Section
Host Interactions with Bacterial Pathogens Study Section (HIBP)
Program Officer
Leitner, Wolfgang W
Project Start
2005-06-01
Project End
2010-02-28
Budget Start
2007-03-01
Budget End
2008-02-29
Support Year
3
Fiscal Year
2007
Total Cost
$260,750
Indirect Cost

  Institution

Name
University of Texas Health Center at Tyler
Department
Anatomy/Cell Biology
Type
Other Domestic Higher Education
DUNS #
800772337
City
Tyler
State
TX
Country
United States
Zip Code
75708

  Publications

Wang, Xisheng; Barnes, Peter F; Huang, Fangfang et al. (2012) Early secreted antigenic target of 6-kDa protein of Mycobacterium tuberculosis primes dendritic cells to stimulate Th17 and inhibit Th1 immune responses. J Immunol 189:3092-103
Samten, Buka; Wang, Xisheng; Barnes, Peter F (2011) Immune regulatory activities of early secreted antigenic target of 6-kD protein of Mycobacterium tuberculosis and implications for tuberculosis vaccine design. Tuberculosis (Edinb) 91 Suppl 1:S114-8
Peng, Hui; Wang, Xisheng; Barnes, Peter F et al. (2011) The Mycobacterium tuberculosis early secreted antigenic target of 6 kDa inhibits T cell interferon-? production through the p38 mitogen-activated protein kinase pathway. J Biol Chem 286:24508-18
Periasamy, Sivakumar; Dhiman, Rohan; Barnes, Peter F et al. (2011) Programmed death 1 and cytokine inducible SH2-containing protein dependent expansion of regulatory T cells upon stimulation With Mycobacterium tuberculosis. J Infect Dis 203:1256-63
Pasquinelli, Virginia; Townsend, James C; Jurado, Javier O et al. (2009) IFN-gamma production during active tuberculosis is regulated by mechanisms that involve IL-17, SLAM, and CREB. J Infect Dis 199:661-5
Dhiman, Rohan; Indramohan, Mohanalaxmi; Barnes, Peter F et al. (2009) IL-22 produced by human NK cells inhibits growth of Mycobacterium tuberculosis by enhancing phagolysosomal fusion. J Immunol 183:6639-45
Barnes, Peter F; Samten, Buka; Shams, Homayoun et al. (2009) Progress in understanding the human immune responses to Mycobacterium tuberculosis. Tuberculosis (Edinb) 89 Suppl 1:S5-9
Wang, Xisheng; Barnes, Peter F; Dobos-Elder, Karen M et al. (2009) ESAT-6 inhibits production of IFN-gamma by Mycobacterium tuberculosis-responsive human T cells. J Immunol 182:3668-77
Roy, Sugata; Barnes, Peter F; Garg, Ankita et al. (2008) NK cells lyse T regulatory cells that expand in response to an intracellular pathogen. J Immunol 180:1729-36
Samten, Buka; Townsend, James C; Weis, Steven E et al. (2008) CREB, ATF, and AP-1 transcription factors regulate IFN-gamma secretion by human T cells in response to mycobacterial antigen. J Immunol 181:2056-64

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