AUTHOR=Feng Siyuan , Hong Zhongsi , Zhang Guoliang , Li Jiachen , Tian Guo-Bao , Zhou Haibo , Huang Xi 

TITLE=Mycobacterium PPE31 Contributes to Host Cell Death

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2021.629836

DOI=10.3389/fcimb.2021.629836

ISSN=2235-2988

ABSTRACT=<p>Genome scale mutagenesis identifies many genes required for mycobacterial infectivity and survival, but their contributions and mechanisms of action within the host are poorly understood. Using CRISPR interference, we created a knockdown of <italic>ppe31<sup>Mm</sup></italic> gene in <italic>Mycobacterium marinum</italic> (<italic>M. marinum</italic>), which reduced the resistance to acid medium. To further explore the function of PPE31, the <italic>ppe31</italic> mutant strain was generated in <italic>M. marinum</italic> and <italic>Mycobacterium tuberculosis</italic> (<italic>M. tuberculosis</italic>), respectively. Macrophages infected with the <italic>ppe31<sup>Mm</sup></italic> mutant strain caused a reduced inflammatory mediator expressions. In addition, macrophages infected with <italic>M. marinum</italic> Δ<italic>ppe31<sup>Mm</sup></italic> had decreased host cell death dependent on JNK signaling. Consistent with these results, deletion of <italic>ppe31<sup>Mtb</sup></italic> from <italic>M. tuberculosis</italic> increased the sensitivity to acid medium and reduced cell death in macrophages. Furthermore, we demonstrate that both <italic>ppe31</italic> mutants from <italic>M. marinum</italic> and <italic>M. tuberculosis</italic> resulted in reduced survival in macrophages, and the survivability of <italic>M. marinum</italic> was deceased in zebrafish due to loss of <italic>ppe31<sup>Mm</sup></italic>. Our findings confirm that PPE31 as a virulence associated factor that modulates innate immune responses to mycobacterial infection.</p>