MPT64 protein from Mycobacterium tuberculosis inhibits apoptosis of macrophages through NF-kB-miRNA21-Bcl-2 pathway.

MPT64 is one of the secreted proteins from Mycobacterium tuberculosis. Little is known about its role in infection by Mycobacterium tuberculosis. In this study, we demonstrated that MPT64 could dose-dependently inhibit the apoptosis of RAW264.7 macrophages induced by PPD-BCG. Quantitative real-time PCR results showed that the expression of bcl-2 increased in macrophages treated with MPT64 compared with PPD-treated cells. Furthermore, the results provided strong evidence that bcl-2 up-regulation was positively controlled by miRNA-21. Finally, NF-κB was identified as the transcription factor for miRNA-21 using a ChIP assay. It can be concluded from our study that MPT64 could inhibit the apoptosis of RAW264.7 macrophages through the NF-κB-miRNA21-Bcl-2 pathway.