期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2017
卷号：114
期号：41
页码：E8711-E8720
DOI：10.1073/pnas.1707792114
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Mycobacterium tuberculosis ’ success as a pathogen comes from its ability to evade degradation by macrophages. Normally macrophages clear microorganisms that activate pathogen-recognition receptors (PRRs) through a lysosomal-trafficking pathway called “LC3-associated phagocytosis” (LAP). Although M . tuberculosis activates numerous PRRs, for reasons that are poorly understood LAP does not substantially contribute to M . tuberculosis control. LAP depends upon reactive oxygen species (ROS) generated by NADPH oxidase, but M . tuberculosis fails to generate a robust oxidative response. Here, we show that CpsA, a LytR-CpsA-Psr (LCP) domain-containing protein, is required for M . tuberculosis to evade killing by NADPH oxidase and LAP. Unlike phagosomes containing wild-type bacilli, phagosomes containing the Δ cpsA mutant recruited NADPH oxidase, produced ROS, associated with LC3, and matured into antibacterial lysosomes. Moreover, CpsA was sufficient to impair NADPH oxidase recruitment to fungal particles that are normally cleared by LAP. Intracellular survival of the Δ cpsA mutant was largely restored in macrophages missing LAP components ( Nox2 , Rubicon , Beclin , Atg5 , Atg7 , or Atg16L1 ) but not in macrophages defective in a related, canonical autophagy pathway ( Atg14 , Ulk1 , or cGAS ). The Δ cpsA mutant was highly impaired in vivo, and its growth was partially restored in mice deficient in NADPH oxidase, Atg5 , or Atg7 , demonstrating that CpsA makes a significant contribution to the resistance of M . tuberculosis to NADPH oxidase and LC3 trafficking in vivo. Overall, our findings reveal an essential role of CpsA in innate immune evasion and suggest that LCP proteins have functions beyond their previously known role in cell-wall metabolism.
