Title A small hairpin RNA targeting myeloid cell leukemia-1 enhances apoptosis in host macrophages infected with Mycobacterium tuberculosis
Author Fei-yu Wang1,2, Yu-qing Zhang1,2, Xin-min Wang2,3, Chan Wang2,4, Xiao-fang Wang1,2, Jiang-dong Wu1,2, Fang Wu1,2, Wan-jiang Zhang1,2, and Le Zhang1,2*
Address 1Department of Pathophysiology, Medical College of Shihezi University, Xinjiang, P. R. China, 2Key Laboratory of Xinjiang Endemic and Ethnic Diseases Cooperated by Education Ministry with Xinjiang Province, Xinjiang, Shihezi, P. R. China, 3Department of Urinary Surgery, the First Affiliated Hospital, Xinjiang, Shihezi, P. R. China, 4Department of Pathogen Biology and Immunology, Medical College of Shihezi University, Xinjiang, P. R. China
Bibliography Journal of Microbiology, 54(4),330-337, 2016,
DOI 10.1007/s12275-016-5627-5
Key Words apoptosis, Mcl-1, Mcl-1-shRNA, Mycobacterium tuberculosis, host macrophages
Abstract Myeloid cell leukemia-1 (Mcl-1) plays an important role in various cell survival pathways. Some studies indicated that the expression of Mcl-1 was upregulated in host cells during infection with the virulent Mycobacterium tuberculosis strain, H37Rv. The present study was designed to investigate the effect of inhibiting Mcl-1 expression both in vivo and in vitro on apoptosis of host macrophages infected with M. tuberculosis using a small hairpin (sh)RNA. Mcl-1 expression was detected by the real time-polymerase chain reaction, western blotting, and immunohistochemistry. Flow cytometry and transmission electron microscopy were used to measure host macrophage apoptosis. We found elevated Mcl-1 levels in host macrophages infected with M. tuberculosis H37Rv. The expression of Mcl-1 was downregulated efficiently in H37Rv-infected host macrophages using shRNA. Knockdown of Mcl-1 enhanced the extent of apoptosis in H37Rv-infected host macrophages significantly. The increased apoptosis correlated with a decrease in M. tuberculosis colony forming units recovered from H37Rv-infected cells that were treated with Mcl-1-shRNA. Reducing Mcl-1 accumulation by shRNA also reduced accumulation of the anti-apoptotic gene, Bcl-2, and increased expression of the pro-apoptotic gene, Bax, in H37Rv-infected host macrophages. Our results showed that specific knockdown of Mcl-1 expression increased apoptosis of host macrophages significantly and decreased the intracellular survival of a virulent strain of M. tuberculosis. These data indicate that interference with Mcl-1 expression may provide a new avenue for tuberculosis therapy.