Heat stress prevents lipopolysaccharide-induced apoptosis in pulmonary microvascular endothelial cells by blocking calpain/p38 MAPK signalling.
Pulmonary microvascular endothelial cells (PMECs) injury including apoptosis plays an important role in the pathogenesis of acute lung injury during sepsis. Our recent study has demonstrated that calpain activation contributes to apoptosis in PMECs under septic conditions. This study investigated how calpain activation mediated apoptosis and whether heat stress regulated calpain activation in lipopolysaccharides (LPS)-stimulated PMECs. In cultured mouse primary PMECs, incubation with LPS (1 μg/ml, 24 h) increased active caspase-3 fragments and DNA fragmentation, indicative of apoptosis. These effects of LPS were abrogated by pre-treatment with heat stress (43 °C for 2 h). LPS also induced calpain activation and increased phosphorylation of p38 MAPK. Inhibition of calpain and p38 MAPK prevented apoptosis induced by LPS. Furthermore, inhibition of calpain blocked p38 MAPK phosphorylation in LPS-stimulated PMECs. Notably, heat stress decreased the protein levels of calpain-1/2 and calpain activities, and blocked p38 MAPK phosphorylation in response to LPS. Additionally, forced up-regulation of calpain-1 or calpain-2 sufficiently induced p38 MAPK phosphorylation and apoptosis in PMECs, both of which were inhibited by heat stress. In conclusion, heat stress prevents LPS-induced apoptosis in PMECs. This effect of heat stress is associated with down-regulation of calpain expression and activation, and subsequent blockage of p38 MAPK activation in response to LPS. Thus, blocking calpain/p38 MAPK pathway may be a novel mechanism underlying heat stress-mediated inhibition of apoptosis in LPS-stimulated endothelial cells.
Department of Intensive Care Unit, General Hospital of Guangzhou Military Command, Guangzhou, 510010, China.|Departments of Medicine and Pathology, Critical Illness Research, Lawson Health Research Institute, University of Western Ontario, London, ON, N6A 4G5, Canada.
Zhi-Feng
ZF
Liu
Departments of Medicine and Pathology, Critical Illness Research, Lawson Health Research Institute, University of Western Ontario, London, ON, N6A 4G5, Canada.
Dong
D
Zheng
Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0575, USA.
Guo-Chang
GC
Fan
Departments of Medicine and Pathology, Critical Illness Research, Lawson Health Research Institute, University of Western Ontario, London, ON, N6A 4G5, Canada.
Tianqing
T
Peng
Department of Intensive Care Unit, General Hospital of Guangzhou Military Command, Guangzhou, 510010, China. slei_icu@163.com.|Key Laboratory of Hot Zone Trauma Care and Tissue Repair of PLA, General Hospital of Guangzhou Military Command, Guangzhou, 510010, China. slei_icu@163.com.
Lei
L
Su
D055371:Acute Lung Injury / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002154:Calpain / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism*; D002460:Cell Line; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D005260:Female; D018869:Heat-Shock Response / Q000502:physiology*; D006390:Hemangioendothelioma / Q000378:metabolism / Q000503:physiopathology; D006358:Hot Temperature; D008070:Lipopolysaccharides / Q000494:pharmacology; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D055806:Microvessels / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D018805:Sepsis / Q000378:metabolism / Q000503:physiopathology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D008070:Lipopolysaccharides; D048051:p38 Mitogen-Activated Protein Kinases; D002154:Calpain; D053148:Caspase 3
Apoptosis; Calpain; Heat stress; Lipopolysaccharide; p38 MAPK