Bovine NMRAL2 Protein Blunts Nitric Oxide Production and Inflammatory Response in Infected Bovine Lung Epithelial Cells.

Tuberculosis (TB), primarily caused by () and (), remains the leading cause of death from a single infectious agent globally. Intracellular survival is crucial for their virulence; yet, the underlying mechanisms are not fully understood. This study aimed to demonstrate the significance of a previously unannotated bovine gene ENSBTAG00000011305 in intracellular survival. This gene was termed due to its inclusion of the NmrA domain which has a relation to nitric oxide (NO) production. We used CRISPR/Cas9 to knock out in bovine lung epithelial cells and observed a significant decrease in -induced cell death and the intracellular bacterial count, alongside increased NO levels. A transcriptome analysis revealed the upregulation of pathways linked to NO, IL-6, and TNF-α production, which was confirmed by the increased expression of iNOS, IL-6, and TNF-α. Correspondingly, Western blotting indicated that key signaling pathways, including NF-κB and MAPK, were activated. In conclusion, our findings determined that NMRAL2_Bovine functions as a negative regulator of the inflammatory response induced by infection at the cellular level and, thereby, provide a novel insight into TB pathogenesis and a potential target for developing novel host-directed therapies against TB.