microRNAs in Mycobacterial Infection: Modulation of Host Immune Response and Apoptotic Pathways

Our current knowledge of mycobacterial infections in humans has progressively increased over the past few decades. The infection of Mycobacterium tuberculosis causes tuberculosis (TB) disease, which has reasoned for excessive morbidity and mortality worldwide, and has become a foremost issue of health problem globally. Mycobacterium leprae, another member of the family Mycobacteriaceae, is responsible for causing a chronic disease known as leprosy that mainly affects mucosa of the upper respiratory tract, skin, peripheral nerves, and eyes. Ample amount of existing data suggests that pathogenic mycobacteria have skilled in utilizing different mechanisms to escape or offset the host immune responses. They hijack the machinery of immune cells through the modulation of microRNAs (miRs), which regulate gene expression and immune responses of the host. Evidence shows that miRs have now gained considerable attention in the research, owing to their involvement in a broad range of inflammatory processes that are further implicated in the pathogenesis of several diseases. However, the knowledge of functions of miRs during mycobacterial infections remains limited. This review summarises recent findings of differential expression of miRs, which are used to good advantage by mycobacteria in offsetting host immune responses generated against them.