A putative Mycobacterium tuberculosis glyoxalase Rv0801 promotes bacterial fitness by alleviating methylglyoxal stress and blunts NRF2-mediated antioxidant defenses

Introduction Methylglyoxal (MG), a toxic metabolic byproduct, functions as a potent antibacterial weapon deployed by macrophages. The glyoxalase system represents the primary microbial defense against MG, yet its role in Mycobacterium tuberculosis pathogenesis remains incompletely defined. Methods To define the function of the putative M. tuberculosis glyoxalase Rv0801 and its homolog MSMEG_5827, we used genetic engineering in Mycobacterium smegmatis MC 2 -155, coupled with growth and macrophage infection assays. Host mechanisms were dissected via transcriptomic and biochemical analysis of the KEAP1-NRF2 antioxidant pathway and pro-inflammatory responses. Results We demonstrate that Rv0801, conferring robust MG tolerance in a mycothiol (MSH)-dependent manner, is essential for bacterial fitness under MG stress. Mechanistically, Rv0801 orchestrates a dual-pathway interference within infected macrophages: by detoxifying MG, it suppresses the host KEAP1-NRF2 antioxidant pathway and concurrently dampens immunoprotective responses. This coordinated suppression compromises macrophage-mediated bacterial clearance. Discussion These findings establish Rv0801-mediated MG stress management as a critical virulence mechanism and highlight the bacterial glyoxalase as a promising target for tuberculosis therapy.