Keywords: Tuberculosis; Macrophage; Phagosome Biology; Functional genomics
Mycobacterium tuberculosis is a leading threat to human health,
killing 40,000 people a week and causing 8 million new cases of disease
every year. Current vaccination and chemotherapy strategies are unsatisfactory,
making development of novel control strategies an important
Rational design of such strategies requires an understanding of the mechanisms by which M.tuberculosis is able to infect individuals and cause disease.
Central to the success of M. tuberculosis as a pathogen is an ability to replicate inside the normally destructive phagosomal compartments of macrophages. TB-MACS propose to use innovative genetic screens to reveal the genetic and mechanistic basis of this characteristic. Specifically TB-MACS will use a microarray based screening of an M. tuberculosis mutant library in two separate selections to identify mutants that are unable to inhibit phagosome acidification and/or unable to inhibit fusion of the phagosome with hydrolytic lysosomes. Mutants identified in these assays will be isolated and characterised with respect to intracellular trafficking and growth in human macrophages. The in vivo phenotypes of the phagosome mutants will be assessed in murine and guinea pig models of tuberculosis.
To begin to understand the mechanisms encoded by the mutated
genes, TBMACS will make a detailed examination of the proteomes and transcriptomes
of selected mutants.
TB-MACS brings together three laboratories with complementary skills and facilities in high-throughput genetic screening, flow-cytometry, cell biology, transcriptomics and proteomics - the net result of which is a unique project that is able to provide system-wide answers to important unanswered questions about M.tuberculosis virulence.
TB-MACS will contribute to improving human health by defining bacterial products and processes that are essential to infection, and which will be useful in the rational development of new drugs and vaccines against tuberculosis.
To form a rational platform on which to determine novel drug targets and vaccine strategies against M. tuberculosis, the processes that allow the bacterium to thrive in vivo need to be identified. Furthermore, the molecular mechanisms behind these processes need to be understood. A key faculty of the bacterium is its ability to grow inside the cells of its host, principally within the macrophage. Multiple factors are involved in intracellular survival including a variety of strategies to avoid and subvert the immune response. Perhaps the most fundamental requirement of intracellular growth is the ability of M. tuberculosis to interfere with the host cell endosomal pathway, preventing acidification of the phagosome compartment in which it resides and stopping its fusion with hydrolytic microbicidal lysosomes .The mechanisms by which M. tuberculosis interferes with the host cell endosomal machinery have yet to be fully understood.
The overarching aim of TB-MACS is to understand the genetic and molecular basis by which Mycobacterium tuberculosis is able to manipulate the macrophage phagosome, leading to bacterial survival and replication. Understanding these mechanisms will be important to the future development of novel drug and vaccine strategies. Specifically, TB-MACS will:
Identification of the genes and molecular mechanisms that allow M.tuberculosis to modulate the macrophage phagosome allowing bacteria to grow and cause disease
Information derived from the project will help identify novel drug targets for consideration in the development of chemotherapy strategies. Mycobacterial mutants generated during TBMACS may form the basis of novel attenuated vaccine strains.
School of Biomedical and Molecular Sciences
University of Surrey
Tel: +44 (0)1483 686423
Fax: +44 (0)1483 686401
|Official Address||Other Information|
|2||Olivier Neyrolles||Unit of Mycobacterial Genetics
28 rue de Dr Roux,
|Tel: +33 1 45688840
Fax: +33 1 45688843
|3||Jelle Thole||Edelhertweg 15, PO box 65
ID-Lelystad, Instituut voor Dierhouderij
en Diergezondheid bv, Lelystad
8200 AB Netherlands
|Tel: +31 320 238508
Fax: +31 320 238961