title: Calpain-1 induces apoptosis in pulmonary microvascular endothelial cells under septic conditions.
abstract: This study was to investigate the role of calpain in the apoptosis of pulmonary microvascular endothelial cells (PMEC) during septic plasma stimulation. Septic plasma was collected from endotoxemic mice. In cultured PMEC, incubation with septic plasma stimulated calpain activation, increased caspase-3 activity and induced apoptotic cell death. These effects of septic plasma were abrogated by knockdown of calpain-1 but not calpain-2 using specific siRNA. Consistently, treatment with calpain inhibitor-III, or over-expression of calpastatin, an endogenous calpain inhibitor significantly decreased apoptosis induced by septic plasma. Septic plasma also induced NADPH oxidase activation and reactive oxygen species (ROS) production. Inhibiting NADPH oxidase or scavenging ROS attenuated calpain activity and decreased apoptosis in PMEC during septic plasma stimulation. In summary, our study demonstrates that ROS produced from NADPH oxidase stimulates calpain-1 activation, which induces apoptosis under septic conditions. Thus, targeting calpain-1/calpastatin may represent a potential strategy to protect against endothelial injury in sepsis.
authors.affiliation: Critical Illness Research, Lawson Health Research Institute, VRL A6-140, 800 Commissioners Road, London, Ontario, Canada.
authors.forename: Houxiang
authors.initials: H
authors.lastname: Hu
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Lefeng
authors.initials: L
authors.lastname: Wang
authors.forename: Sanjay
authors.initials: S
authors.lastname: Mehta
authors.forename: Qingping
authors.initials: Q
authors.lastname: Feng
authors.forename: Ruizhen
authors.initials: R
authors.lastname: Chen
authors.forename: Tianqing
authors.initials: T
authors.lastname: Peng
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002154:Calpain / Q000633:toxicity*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D005260:Female; D008168:Lung / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008833:Microcirculation; D018805:Sepsis / Q000378:metabolism*
chemical_list: D002154:Calpain