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Updated: Jun 3, 2026
A Microscopic Phenotypic Assay for the Quantification of Intracellular Mycobacteria Adapted for High-throughput/High-content Screening
Published on: January 17, 2014
Genome-wide analysis of the host intracellular network that regulates survival of Mycobacterium tuberculosis
Dhiraj Kumar1, Lekha Nath, Md Azhar Kamal
1Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
Abstract:
We performed a genome-wide siRNA screen to identify host factors that regulated pathogen load in human macrophages infected with a virulent strain of Mycobacterium tuberculosis. Iterative rounds of confirmation, followed by validation, identified 275 such molecules that were all found to functionally associate with each other through a dense network of interactions. This network then yielded to a molecular description of the host cell functional modules that were both engaged and perturbed by the pathogen. Importantly, a subscreen against a panel of field isolates revealed that the molecular composition of the host interface varied with both genotype and the phenotypic properties of the pathogen. An analysis of these differences, however, permitted identification of those host factors that were invariantly involved, regardless of the diversification in adaptive mechanisms employed by the pathogen. Interestingly, these factors were found to predominantly function through the regulation of autophagy.
Insights
Researchers identified 275 host molecules regulating Mycobacterium tuberculosis infection in macrophages. These factors, primarily controlling autophagy, form a network crucial for host defense against diverse bacterial strains.
Area of Science:
- Immunology
- Microbiology
- Genetics
Background:
- Mycobacterium tuberculosis (Mtb) infection involves complex host-pathogen interactions.
- Identifying host factors regulating Mtb pathogenesis is crucial for therapeutic strategies.
Purpose of the Study:
- To identify host factors controlling Mtb pathogen load in human macrophages.
- To elucidate the molecular network and functional modules engaged by Mtb.
- To determine host factor conservation across diverse Mtb strains.
Main Methods:
- Genome-wide siRNA screen in human macrophages infected with Mtb.
- Iterative confirmation and validation of identified host factors.
- Network analysis to map molecular interactions.
- Subscreen with Mtb field isolates to assess host interface variability.
Main Results:
- Identified 275 host molecules regulating Mtb load.
- Discovered a dense interaction network among these molecules.
- Characterized host cell functional modules perturbed by Mtb.
- Revealed variability in host-pathogen interactions based on Mtb genotype and phenotype.
- Identified invariant host factors crucial for defense across Mtb strains.
Conclusions:
- Host-pathogen interactions are modulated by Mtb diversity.
- A conserved set of host factors, predominantly regulating autophagy, are essential for controlling Mtb infection.
- Understanding these host networks offers potential therapeutic targets.
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