M. tuberculosis (Mtb) causes latent infections that affect a third of the world's population and active tuberculosis kills two million people every year. Chemotherapy of tuberculosis requires long treatment regimens and is complicated by the emergence of multi-drug resistant and extensively drug resistant Mtb strains. New drugs that shorten TB chemotherapy and cure drug resistant TB are urgently needed. Mtb encounters an acidic pH within phagosomes of interferon-3 activated macrophages and must prevent excessive entry of protons into its cytosol. One pathway important for pH homeostasis and virulence of Mtb depends on the membrane-associated serine hydrolase Rv3671c. The goals of this proposal are to determine the molecular mechanisms by which Rv3671c protects Mtb from intracellular acidification and contributes to virulence.
Our specific aims are: I. To determine why Rv3671c is required for resistant of Mtb against acid. We will investigate the mechanism by which this serine hydrolase controls pH and acid resistance. II. To determine why Rv3671c is required for persistence in activated macrophages and mice. We will investigate if Rv3671c affects phagosome maturation in IFN-3 activated macrophages. We will use genetically altered mice to determine if Rv3671c protects against host defense mechanisms, which act synergistically with phagosome acidification. III. To identify small molecules that interfere with pH homeostasis in Mtb. We will use a high- throughput screen to identify such inhibitors, which will help to investigate the biology of intrabacterial pH homeostasis in Mtb and facilitate the development of new drugs against tuberculosis.
Tuberculosis (TB) is one of the world's most devastating diseases. It is responsible for more than two million deaths and eight million new cases annually. Work outlined in this proposal will investigate virulence mechanisms that allow Mtb to persist within its host and cause disease. It will help identify novel drug targets that might facilitate the development of new drugs against tuberculosis.
|Botella, Helene; Vaubourgeix, Julien; Lee, Myung Hee et al. (2017) Mycobacterium tuberculosis protease MarP activates a peptidoglycan hydrolase during acid stress. EMBO J 36:536-548|
|Zhao, Nan; Darby, Crystal M; Small, Jennifer et al. (2015) Target-based screen against a periplasmic serine protease that regulates intrabacterial pH homeostasis in Mycobacterium tuberculosis. ACS Chem Biol 10:364-71|
|Zhao, Nan; Sun, Mingna; Burns-Huang, Kristin et al. (2015) Identification of Rv3852 as an Agrimophol-Binding Protein in Mycobacterium tuberculosis. PLoS One 10:e0126211|
|Goodsmith, Nichole; Guo, Xinzheng V; Vandal, Omar H et al. (2015) Disruption of an M. tuberculosis membrane protein causes a magnesium-dependent cell division defect and failure to persist in mice. PLoS Pathog 11:e1004645|
|Small, Jennifer L; Park, Sae Woong; Kana, Bavesh D et al. (2013) Perturbation of cytochrome c maturation reveals adaptability of the respiratory chain in Mycobacterium tuberculosis. MBio 4:e00475-13|
|Darby, Crystal M; Ingólfsson, Helgi I; Jiang, Xiuju et al. (2013) Whole cell screen for inhibitors of pH homeostasis in Mycobacterium tuberculosis. PLoS One 8:e68942|
|Darby, Crystal M; Venugopal, Aditya; Ehrt, Sabine et al. (2011) Mycobacterium tuberculosis gene Rv2136c is dispensable for acid resistance and virulence in mice. Tuberculosis (Edinb) 91:343-7|
|de Carvalho, Luiz Pedro S; Darby, Crystal M; Rhee, Kyu Y et al. (2011) Nitazoxanide Disrupts Membrane Potential and Intrabacterial pH Homeostasis of Mycobacterium tuberculosis. ACS Med Chem Lett 2:849-854|
|Biswas, Tapan; Small, Jennifer; Vandal, Omar et al. (2010) Structural insight into serine protease Rv3671c that Protects M. tuberculosis from oxidative and acidic stress. Structure 18:1353-63|
|Ehrt, Sabine; Schnappinger, Dirk (2009) Mycobacterial survival strategies in the phagosome: defence against host stresses. Cell Microbiol 11:1170-8|