Mycobacterium Tuberculosis Activates the DNA-dependent Cytosolic Surveillance Pathway Within Macrophages
Overview
Microbiology
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Cytosolic bacterial pathogens activate the cytosolic surveillance pathway (CSP) and induce innate immune responses, but how the host detects vacuolar pathogens like Mycobacterium tuberculosis is poorly understood. We show that M. tuberculosis also initiates the CSP upon macrophage infection via limited perforation of the phagosome membrane mediated by the ESX-1 secretion system. Although the bacterium remains within the phagosome, this permeabilization results in phagosomal and cytoplasmic mixing and allows extracellular mycobacterial DNA to access host cytosolic receptors, thus blurring the distinction between "vacuolar" and "cytosolic" pathogens. Activation of cytosolic receptors induces signaling through the Sting/Tbk1/Irf3 axis, resulting in IFN-β production. Surprisingly, Irf3(-/-) mice, which cannot respond to cytosolic DNA, are resistant to long-term M. tuberculosis infection, suggesting that the CSP promotes M. tuberculosis infection. Thus, cytosolic sensing of mycobacterial DNA plays a key role in M. tuberculosis pathogenesis and likely contributes to the high type I IFN signature in tuberculosis.
Cheng H, Chu J, Limjunyawong N, Chen J, Ye Y, Chen K bioRxiv. 2025; .
PMID: 40060571 PMC: 11888413. DOI: 10.1101/2025.02.27.640612.
VPS18 contributes to phagosome membrane integrity in -infected macrophages.
Jani C, Jain N, Marsh A, Uchil P, Doan T, Hudspith M Sci Adv. 2025; 11(5):eadr6166.
PMID: 39888996 PMC: 11784855. DOI: 10.1126/sciadv.adr6166.
Noncanonical roles of ATG5 and membrane atg8ylation in retromer assembly and function.
Paddar M, Wang F, Trosdal E, Hendrix E, He Y, Salemi M Elife. 2025; 13.
PMID: 39773872 PMC: 11706607. DOI: 10.7554/eLife.100928.
Chin J, Abeydeera N, Repasy T, Rivera-Lugo R, Mitchell G, Nguyen V bioRxiv. 2025; .
PMID: 39763950 PMC: 11702572. DOI: 10.1101/2024.12.16.628616.
ATG9A facilitates the closure of mammalian autophagosomes.
Javed R, Mari M, Trosdal E, Duque T, Paddar M, Allers L J Cell Biol. 2025; 224(2).
PMID: 39745851 PMC: 11694768. DOI: 10.1083/jcb.202404047.