Identification of Autophagy-Inhibiting Factors of Mycobacterium tuberculosis by High-Throughput Loss-of-Function Screening.

Autor:	Strong EJ; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA., Jurcic Smith KL; Human Vaccine Institute, Duke University, Durham, North Carolina, USA., Saini NK; Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA., Ng TW; Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA., Porcelli SA; Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA.; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA., Lee S; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA sunhlee@utmb.edu.; Human Vaccine Institute, Duke University, Durham, North Carolina, USA.; Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA.
Jazyk:	angličtina
Zdroj:	Infection and immunity [Infect Immun] 2020 Nov 16; Vol. 88 (12). Date of Electronic Publication: 2020 Nov 16 (Print Publication: 2020).
DOI:	10.1128/IAI.00269-20
Abstrakt:	The interaction of host cells with mycobacteria is complex and can lead to multiple outcomes ranging from bacterial clearance to progressive or latent infection. Autophagy is recognized as one component of host cell responses that has an essential role in innate and adaptive immunity to intracellular bacteria. Many microbes, including Mycobacterium tuberculosis , have evolved to evade or exploit autophagy, but the precise mechanisms and virulence factors are mostly unknown. Through a loss-of-function screening of an M. tuberculosis transposon mutant library, we identified 16 genes that contribute to autophagy inhibition, six of which encoded the PE/PPE protein family. Their expression in Mycobacterium smegmatis confirmed that these PE/PPE proteins inhibit autophagy and increase intracellular bacterial persistence or replication in infected cells. These effects were associated with increased mammalian target of rapamycin (mTOR) activity and also with decreased production of tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β). We also confirmed that the targeted deletion of the pe / ppe genes in M. tuberculosis resulted in enhanced autophagy and improved intracellular survival rates compared to those of wild-type bacteria in the infected macrophages. Differential expression of these PE/PPE proteins was observed in response to various stress conditions, suggesting that they may confer advantages to M. tuberculosis by modulating its interactions with host cells under various conditions. Our findings demonstrated that multiple M. tuberculosis PE/PPE proteins are involved in inhibiting autophagy during infection of host phagocytes and may provide strategic targets in developing therapeutics or vaccines against tuberculosis. (Copyright © 2020 American Society for Microbiology.)
Databáze:	MEDLINE
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