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Mycobacterial origin protein Rv0674 localizes into mitochondria, interacts with D-loop and regulates OXPHOS for

Rikesh Kumar Dubey1, Ekta Dhamija1, Alok Kumar Mishra1

  • 1Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow 226031, India.

Mitochondrion
|December 6, 2020
PubMed

Insights

Mycobacterium tuberculosis protein Rv0674 targets host mitochondria, promoting macrophage apoptosis and enhancing bacterial survival. This novel mechanism involves interaction with mitochondrial DNA, impacting OXPHOS and ATP synthesis.

Area of Science:

  • Microbiology
  • Cell Biology
  • Molecular Biology

Background:

  • Mycobacterium tuberculosis (Mtb) utilizes various strategies to evade host immune responses within macrophages.
  • Understanding Mtb's survival mechanisms is crucial for developing effective tuberculosis treatments.

Purpose of the Study:

  • To identify and characterize novel Mtb proteins involved in host-pathogen interactions.
  • To elucidate the role of the conserved hypothetical protein Rv0674 in Mtb pathogenesis.

Main Methods:

  • Genetic knockout of rv0674 in Mtb.
  • Intracellular infection models using recombinant Mycobacterium smegmatis expressing Rv0674.
  • Mitochondrial DNA interaction studies.
  • Analysis of mitochondrial gene expression (OXPHOS subunits).
  • Measurement of ATP synthesis, mitochondrial membrane potential, and superoxide production.
  • Fluorescent and confocal microscopy for protein localization.

Main Results:

  • Rv0674 knockout (Mtb-KO) resulted in increased Mtb growth.
  • Recombinant Rv0674 expression promoted macrophage apoptotic cell death.
  • Rv0674 interacts with the D-loop of mitochondrial DNA, increasing OXPHOS mRNA expression.
  • Changes in OXPHOS correlated with altered ATP synthesis, mitochondrial membrane potential, and superoxide production.
  • Rv0674 was localized to the mitochondria of infected macrophages and in BAL cells of TB patients.

Conclusions:

  • Rv0674 is a novel Mtb protein localized in host mitochondria.
  • Rv0674 promotes Mtb intracellular survival by inducing macrophage apoptosis via mitochondrial pathways.
  • This protein influences host mitochondrial function, representing a new virulence mechanism for Mtb.
Keywords:
ApoptosisIntracellular survivalMitochondriaMycobacteriaOXPHOSRv0674

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