Mycobacterium tuberculosis (Mtb) is the causative agent of what remains one of the most insidious and invasive of human infections, responsible for up to 2 million deaths per year. For most of the course of disease the basic unit of infection is the infected macrophage, therefore the interplay between these two cell types plays a crucial role in determining the outcome of infection. The project details the identification of host environmental cues and bacterial responses that enable the bacterium to invade and survive within the host cell. Genes up-regulated during infection will be exploited to construct fluorescent reporter Mtb strains that express GFP under defined conditions. These reporter strains will be used for both genetic and chemical screens to dissect out the signaling networks and to identify small molecular inhibitors that will form the foundation of a novel drug discovery program. The central hypothesis is that Mtb relies on environmental cues inside its host cell to activate genetic networks to enable it to adapt and survive, and that genetic or chemical interference with these networks will lead to death of the infecting bacteria.
The Specific Aims are as follows: 1. Identification of genetic """"""""networks"""""""" activated by intracellular infection. Focuses on the identification of intracellular cues that trigger transcriptional activity in Mtb and the construction of reporter strains that express GFP under the regulation of promoters from those genes up- regulated in response to the environmental cue. 2. Exploitation of genetic screens to identify and delineate regulatory networks. These synthetic phenotypes will be utilized to screen for mutants with aberrant regulation of GFP expression. Such a screen will encompass the sensor/regulator machinery including transcriptional control and feedback loops. The phenotypes of these mutants will be probed in tissue culture and animal models of infection to identify those networks most critical to infection of the host. 3. Exploitation of chemical screens to identify small molecule inhibitors of these networks. High-throughput screens will be conducted on the reporter strains to identify small molecule inhibitors that modulate GFP expression. These hits will be analyzed for their activity against Mtb in macrophages and, in collaboration with Vertex Pharmaceuticals, used as lead compounds for novel target identification and drug development.

Public Health Relevance

Tuberculosis remains a serious global problem with the majority of deaths in poor countries. We have no effective vaccines and constant problems with emerging drug resistance. The central premise of this current proposal is that Mtb up-regulates genetic networks to support intracellular survival and that genetic and chemical screens against these sensor/regulator networks will lead to the identification of novel drug targets and lead compounds.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI067027-08
Application #
8461896
Study Section
AIDS-associated Opportunistic Infections and Cancer Study Section (AOIC)
Program Officer
Jacobs, Gail G
Project Start
2005-07-01
Project End
2016-04-30
Budget Start
2013-05-01
Budget End
2014-04-30
Support Year
8
Fiscal Year
2013
Total Cost
$410,343
Indirect Cost
$126,239
Name
Cornell University
Department
Microbiology/Immun/Virology
Type
Schools of Veterinary Medicine
DUNS #
872612445
City
Ithaca
State
NY
Country
United States
Zip Code
14850
Russell, David G (2016) The ins and outs of the Mycobacterium tuberculosis-containing vacuole. Cell Microbiol 18:1065-9
Liu, Yancheng; Tan, Shumin; Huang, Lu et al. (2016) Immune activation of the host cell induces drug tolerance in Mycobacterium tuberculosis both in vitro and in vivo. J Exp Med 213:809-25
Subbian, Selvakumar; Tsenova, Liana; Kim, Mi-Jeong et al. (2015) Lesion-Specific Immune Response in Granulomas of Patients with Pulmonary Tuberculosis: A Pilot Study. PLoS One 10:e0132249
VanderVen, Brian C; Fahey, Ruth J; Lee, Wonsik et al. (2015) Novel inhibitors of cholesterol degradation in Mycobacterium tuberculosis reveal how the bacterium's metabolism is constrained by the intracellular environment. PLoS Pathog 11:e1004679
Tan, Shumin; Russell, David G (2015) Trans-species communication in the Mycobacterium tuberculosis-infected macrophage. Immunol Rev 264:233-48
Podinovskaia, Maria; Russell, David G (2015) Detection and quantification of microbial manipulation of phagosomal function. Methods Cell Biol 126:305-29
Russell, David G; Lee, Wonsik; Tan, Shumin et al. (2014) The Sculpting of the Mycobacterium tuberculosis Genome by Host Cell-Derived Pressures. Microbiol Spectr 2:
Sukumar, Neelima; Tan, Shumin; Aldridge, Bree B et al. (2014) Exploitation of Mycobacterium tuberculosis reporter strains to probe the impact of vaccination at sites of infection. PLoS Pathog 10:e1004394
Podinovskaia, Maria; VanderVen, Brian C; Yates, Robin M et al. (2013) Dynamic quantitative assays of phagosomal function. Curr Protoc Immunol 102:Unit 14.34.
Sakamoto, Kaori; Kim, Mi Jeong; Rhoades, Elizabeth R et al. (2013) Mycobacterial trehalose dimycolate reprograms macrophage global gene expression and activates matrix metalloproteinases. Infect Immun 81:764-76

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