title: Mycobacterium kansasii-induced death of murine macrophages involves endoplasmic reticulum stress responses mediated by reactive oxygen species generation or calpain activation.
abstract: Although pathogenic mechanisms of tuberculosis have been extensively studied, little is known about the pathogenic mechanisms of Mycobacterium kansasii. In this work the influence of virulence and ER-stress mediated apoptosis of macrophages during two different strains of M. kansasii infection was investigated. We show that M. kansasii infection is associated with ER stress-mediated apoptosis in the murine macrophage cell line RAW 264.7. Infection of RAW 264.7 cells in vitro with apoptosis-inducing a clinical isolate of M. kansasii SM-1 (SM-1) resulted in strong induction of ER stress responses compared with M. kansasii type strain (ATCC 12478)-infected RAW 264.7 cells. Interestingly, inhibition of calpain prevented the induction of CHOP and Bip in ATCC 12478-infected RAW 264.7 cells but not in RAW 264.7 cells infected with SM-1. In contrast, reactive oxygen species (ROS) were significantly increased only in RAW 264.7 cells infected with SM-1. We propose that ROS generation is important for triggering ER stress-mediated apoptosis during SM-1 infection, whereas ATCC 12478-induced, ER stress-mediated apoptosis is associated with calpain activation. Our results demonstrate that the ER stress pathway plays important roles in the pathogenesis of M. kansasii infections, and that different strains of M. kansasii induce different patterns of ER stress-mediated apoptosis.
authors.affiliation: Department of Microbiology, Infection Signaling Network Research Center, Research Institute for Medical Sciences, College of Medicine, Chungnam National University, Daejeon 301-747, South Korea.
authors.forename: Yun-Ji
authors.initials: YJ
authors.lastname: Lim
authors.forename: Hong-Hee
authors.initials: HH
authors.lastname: Choi
authors.forename: Ji-Ae
authors.initials: JA
authors.lastname: Choi
authors.forename: Ji Ae
authors.initials: JA
authors.lastname: Jeong
authors.forename: Soo-Na
authors.initials: SN
authors.lastname: Cho
authors.forename: Jung-Hwan
authors.initials: JH
authors.lastname: Lee
authors.forename: Jin Bong
authors.initials: JB
authors.lastname: Park
authors.forename: Hwa-Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Chang-Hwa
authors.initials: CH
authors.lastname: Song
mesh_terms: D000818:Animals; D002154:Calpain / Q000378:metabolism*; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D059865:Endoplasmic Reticulum Stress / Q000502:physiology*; D004789:Enzyme Activation; D005260:Female; D008264:Macrophages / Q000382:microbiology / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009165:Mycobacterium Infections, Nontuberculous / Q000503:physiopathology*; D019909:Mycobacterium kansasii / Q000472:pathogenicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014774:Virulence
chemical_list: D017382:Reactive Oxygen Species; D002154:Calpain; D020169:Caspases