Involvement of Caspase-9 in the Inhibition of Necrosis of RAW 264 Cells Infected with Mycobacterium tuberculosis Export

@article{citeulike:1319397, abstract = {In order to know how caspases contribute to the intracellular fate of Mycobacterium tuberculosis and host cell death in the infected macrophages, we examined the effect of benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethane (z-VAD-fmk), a broad-spectrum caspase inhibitor, on the growth of M. tuberculosis H37Rv in RAW 264 cells. In the cells treated with z-VAD-fmk, activation of caspase-8, caspase-3/7, and caspase-9 was clearly suppressed, and DNA fragmentation of the infected cells was also reduced. Under this experimental condition, it was found that the treatment markedly inhibited bacterial growth inside macrophages. The infected cells appeared to undergo cell death of the necrosis type in the presence of z-VAD-fmk. We further found that z-VAD-fmk treatment resulted in the generation of intracellular reactive oxygen species (ROS) in the infected cells. By addition of a scavenger of ROS, the host cell necrosis was inhibited and the intracellular growth of H37Rv was significantly restored. Among inhibitors specific for each caspase, only the caspase-9-specific inhibitor enhanced the generation of ROS and induced necrosis of the infected cells. Furthermore, we found that severe necrosis was induced by infection with H37Rv but not H37Ra in the presence of z-VAD-fmk. Caspase-9 activation was also detected in H37Rv-infected cells, but H37Ra never induced such caspase-9 activation. These results indicated that caspase-9, which was activated by infection with virulent M. tuberculosis, contributed to the inhibition of necrosis of the infected host cells, presumably through suppression of intracellular ROS generation. 10.1128/IAI.01639-06}, author = {Uchiyama, Ryosuke and Kawamura, Ikuo and Fujimura, Takao and Kawanishi, Michiko and Tsuchiya, Kohsuke and Tominaga, Takanari and Kaku, Taijin and Fukasawa, Yutaka and Sakai, Shunsuke and Nomura, Takamasa and Mitsuyama, Masao}, citeulike-article-id = {1319397}, citeulike-linkout-0 = {http://dx.doi.org/10.1128/IAI.01639-06}, citeulike-linkout-1 = {http://iai.asm.org/cgi/content/abstract/75/6/2894}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/17403866}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=17403866}, doi = {10.1128/IAI.01639-06}, journal = {Infect. Immun.}, keywords = {murine\_macrophage, mycobacterium\_tuberculosis, necrosis, tnf}, month = {June}, number = {6}, pages = {2894--2902}, posted-at = {2007-05-22 15:31:17}, priority = {0}, title = {Involvement of Caspase-9 in the Inhibition of Necrosis of RAW 264 Cells Infected with Mycobacterium tuberculosis}, url = {http://dx.doi.org/10.1128/IAI.01639-06}, volume = {75}, year = {2007} }

TY - JOUR ID - citeulike:1319397 L3 - citeulike-article-id:1319397 N2 - In order to know how caspases contribute to the intracellular fate of Mycobacterium tuberculosis and host cell death in the infected macrophages, we examined the effect of benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethane (z-VAD-fmk), a broad-spectrum caspase inhibitor, on the growth of M. tuberculosis H37Rv in RAW 264 cells. In the cells treated with z-VAD-fmk, activation of caspase-8, caspase-3/7, and caspase-9 was clearly suppressed, and DNA fragmentation of the infected cells was also reduced. Under this experimental condition, it was found that the treatment markedly inhibited bacterial growth inside macrophages. The infected cells appeared to undergo cell death of the necrosis type in the presence of z-VAD-fmk. We further found that z-VAD-fmk treatment resulted in the generation of intracellular reactive oxygen species (ROS) in the infected cells. By addition of a scavenger of ROS, the host cell necrosis was inhibited and the intracellular growth of H37Rv was significantly restored. Among inhibitors specific for each caspase, only the caspase-9-specific inhibitor enhanced the generation of ROS and induced necrosis of the infected cells. Furthermore, we found that severe necrosis was induced by infection with H37Rv but not H37Ra in the presence of z-VAD-fmk. Caspase-9 activation was also detected in H37Rv-infected cells, but H37Ra never induced such caspase-9 activation. These results indicated that caspase-9, which was activated by infection with virulent M. tuberculosis, contributed to the inhibition of necrosis of the infected host cells, presumably through suppression of intracellular ROS generation. 10.1128/IAI.01639-06 IS - 6 JF - Infect. Immun. EP - 2902 TI - Involvement of Caspase-9 in the Inhibition of Necrosis of RAW 264 Cells Infected with Mycobacterium tuberculosis VL - 75 SP - 2894 KW - murine_macrophage KW - mycobacterium_tuberculosis KW - necrosis KW - tnf AU - Uchiyama, Ryosuke AU - Kawamura, Ikuo AU - Fujimura, Takao AU - Kawanishi, Michiko AU - Tsuchiya, Kohsuke AU - Tominaga, Takanari AU - Kaku, Taijin AU - Fukasawa, Yutaka AU - Sakai, Shunsuke AU - Nomura, Takamasa AU - Mitsuyama, Masao PY - 2007/06/01/ UR - http://dx.doi.org/10.1128/IAI.01639-06 ER -