Infection of J774A.1 with different Mycobacterium species induces differential immune and miRNA-related responses

Macrophages act as a reservoir for Mycobacterium tuberculosis, producing latent infection in approximately 90% of infected people. In this study, J774A.1 mouse macrophage cell line response and microRNA (miRNA) expression during infection with the most relevant mycobacterial strains for humans (M. tuberculosis, M. bovis and M. bovis BCG) was explored. No significant differences in bacillary loads were observed between activate and naive macrophages infected with M. tuberculosis and M. bovis. Nitrite production inhibition and infection control were in accordance with the virulence of the strain. Expression of let-7e, miR-21, miR-155, miR-210 and miR-223 was opposite in the two species and miR-146b* and miR-1224 expression seemed to be part of the general response to infection.