NCoR1 controls Mycobacterium tuberculosis growth in myeloid cells by regulating the AMPK-mTOR-TFEB axis.

Mycobacterium tuberculosis (Mtb) defends host-mediated killing by repressing the autophagolysosome machinery. For the first time, we report NCoR1 co-repressor as a crucial host factor, controlling Mtb growth in myeloid cells by regulating both autophagosome maturation and lysosome biogenesis. We found that the dynamic expression of NCoR1 is compromised in human peripheral blood mononuclear cells (PBMCs) during active Mtb infection, which is rescued upon prolonged anti-mycobacterial therapy. In addition, a loss of function in myeloid-specific NCoR1 considerably exacerbates the growth of M. tuberculosis in vitro in THP1 differentiated macrophages, ex vivo in bone marrow-derived macrophages (BMDMs), and in vivo in NCoR1MyeKO mice. We showed that NCoR1 depletion controls the AMPK-mTOR-TFEB signalling axis by fine-tuning cellular adenosine triphosphate (ATP) homeostasis, which in turn changes the expression of proteins involved in autophagy and lysosomal biogenesis. Moreover, we also showed that the treatment of NCoR1 depleted cells by Rapamycin, Antimycin-A, or Metformin rescued the TFEB activity and LC3 levels, resulting in enhanced Mtb clearance. Similarly, expressing NCoR1 exogenously rescued the AMPK-mTOR-TFEB signalling axis and Mtb killing. Overall, our data revealed a central role of NCoR1 in Mtb pathogenesis in myeloid cells.

NCoR1: a key player regulating mycobacterium tuberculosis pathogenesis.

Mycobacterium tuberculosis (Mtb) employs a multifaceted arsenal to elude host defense mechanisms, including those associated with autophagy and lysosome function. Within the realm of host-pathogen interactions, NCOR1, a well-recognized transcriptional co-repressor, is known to associate with a multitude of protein complexes to effect the repression of a diverse spectrum of genes. However, its role in regulating macroautophagy/autophagy, lysosome biogenesis, and, by extension, Mtb pathogenesis remains unexplored. The depletion of NCOR1 assumes a pivotal role in the control of the AMPK-MTOR-TFEB signaling axis, thereby fine-tuning cellular ATP homeostasis. This finely orchestrated adjustment further alters the profile of proteins involved in autophagy and lysosomal biogenesis through its master regulator, TFEB, culminating in the increased Mtb survival within the host milieu. Furthermore, the treatment of NCOR1-depleted cells with either rapamycin, antimycin A, or metformin demonstrates a capacity to restore the TFEB activity and LC3-II levels, consequently restoring the capacity of host cells to clear Mtb. Additionally, exogenous NCOR1 expression rescues the AMPK-MTOR-TFEB signaling axis and essentially the autophagic induction machinery. Overall, these findings demonstrate a crucial role of NCOR1 in regulating Mtb pathogenesis within myeloid cells and sheds light toward its involvement in the development of novel host-directed therapies.