M. tuberculosis (Mtb) is one of the leading causes of death worldwide and claims millions of lives annually. Approximately ~1.7 billion people worldwide are asymptomatically infected with the tubercle bacillus and constitute a major impediment to worldwide public health control measures. Previous work had shown that a point mutation (Arg515->His) in the 4.2 domain of RpoV, the principal sigma factor in Mycobacterium bovis, is attenuating. Mice infected with MtbwhiB3 showed significantly longer survival times than mice infected with the wild type Mtb. In addition, the lungs of MtbwhiB3-infected mice appeared much less adversely affected. Recent studies have shown that WhiB3 is a 4Fe-4S cluster protein and initiates the metabolic switchover to the preferred in vivo carbon source, fatty acids. We hypothesize that WhiB3 is an intracellular redox sensor that maintains redox homeostasis. To better understand the mechanism of this physiological event, we will identify the WhiB3 amino acids necessary for effective iron-sulfur (Fe-S) reconstitution, and use electron paramagnetic resonance spectroscopy (EPR) to characterize these mutated proteins. We will use genome-wide expression profiling to examine the contribution of WhiB3 in maintaining redox homeostasis, and analyze the metabolite profile of MtbwhiB3. These studies will characterize WhiB3 as a potential target for interventions that may abolish virulence, but not growth. These studies will also provide insight into understanding how Mtb subvert host immunity.

Public Health Relevance

The ability of small numbers of Mycobacterium tuberculosis (Mtb) to lay dormant in humans without causing disease is central to the biology of the disease. We will examine how Mtb enters a persistent state, and hope to translate this knowledge into new interventions to reduce tuberculosis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI058131-10
Application #
8636974
Study Section
Bacterial Pathogenesis Study Section (BACP)
Program Officer
Lacourciere, Karen A
Project Start
2003-12-01
Project End
2015-03-31
Budget Start
2014-04-01
Budget End
2015-03-31
Support Year
10
Fiscal Year
2014
Total Cost
$362,588
Indirect Cost
$115,088
Name
University of Alabama Birmingham
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
063690705
City
Birmingham
State
AL
Country
United States
Zip Code
35294
Kumar, Ashwani; Deshane, Jessy S; Crossman, David K et al. (2008) Heme oxygenase-1-derived carbon monoxide induces the Mycobacterium tuberculosis dormancy regulon. J Biol Chem 283:18032-9
Kumar, Ashwani; Toledo, Jose C; Patel, Rakesh P et al. (2007) Mycobacterium tuberculosis DosS is a redox sensor and DosT is a hypoxia sensor. Proc Natl Acad Sci U S A 104:11568-73
Singh, Amit; Guidry, Loni; Narasimhulu, K V et al. (2007) Mycobacterium tuberculosis WhiB3 responds to O2 and nitric oxide via its [4Fe-4S] cluster and is essential for nutrient starvation survival. Proc Natl Acad Sci U S A 104:11562-7
Singh, Amit; Mai, Deborah; Kumar, Ashwani et al. (2006) Dissecting virulence pathways of Mycobacterium tuberculosis through protein-protein association. Proc Natl Acad Sci U S A 103:11346-51