Mycobacterium tuberculosis Rv2521 promotes ferroptosis-dependent pathogenicity by inhibiting NF-κB activation

Mycobacterium tuberculosis (M.tb) manipulates host ferroptosis, a novel form of programmed cell death, to enhance its pathogenicity. However, the precise molecular mechanisms remain poorly be understood. A key feature of M.tb evolution is the set of eukaryotic-like secreted proteins that can modulate host immunological system. This study aimed to identify such proteins involved in host ferroptosis and their regulatory mechanisms. Our results showed that Rv2521, one of the secreted proteins, significantly promotes ferroptosis by modulating glutathione peroxidase 4 (GPX4) expression in M.tb-infected macrophages. Rv2521 downregulates GPX4 by binding to NF-κB, inhibiting NF-κB/p65 phosphorylation, thereby blocking the activation of NF-κB signaling pathway and reducing NF-κB/p65 occupancy at the GPX4 promoter. Importantly, these regulatory effects can be reversed using ferroptosis or NF-κB inhibitors. Additionally, our results found that Rv2521 directly interacts with NF-κB. Compared to wild-type and complemented strains, the Rv2521 knockout strain exhibited reduced survival and dissemination in macrophages due to the suppression of ferroptosis and the enhanced immune evasion. Collectively, our results identify a novel M.tb eukaryotic-like secreted protein involved in ferroptosis and provide new insights into M.tb-host interactions, offering potential host-directed therapy strategies for tuberculosis.