Role of PRMT5 in regulating ferritinophagy during Mycobacterium tuberculosis infection.

Mycobacterium tuberculosis (Mtb) increases the availability of free iron, resulting in ferroptosis of macrophages to facilitate its survival and dissemination. A critical factor for elevated levels of labile iron is the overt accumulation of nuclear receptor coactivator 4 (NCOA4), which promotes autophagic degradation of ferritin in a process termed ferritinophagy. Here, we identify a novel post-translational modification on NCOA4 that is essential for its interaction with ferritin in the iron-replete condition of Mtb-infected cells. Specifically, protein arginine methyltransferase 5 (PRMT5) confers symmetric dimethylation on NCOA4, which promotes ferritinophagy-mediated ferroptosis. Using loss-of-function studies, we show that PRMT5 is required for lipid peroxidation, bacterial survival, and dissemination in Mtb-infected mice. Additionally, the overexpression of a methylation-deficient mutant of NCOA4 phenocopies the depletion of PRMT5 and reduces ferritinophagy in Mtb-infected cells. Mechanistically, we identify that PRMT5-mediated methylation enhances the cytoplasmic retention of NCOA4 and reduces its nuclear availability. Thus, our findings uncover the key interaction between NCOA4 and ferritin that regulates ferroptosis and mycobacterial survival during infection. Perturbation of this interaction results in reduced Mtb loads and alleviated disease pathology.