Cardiovascular Research Advance Access [Accepted Manuscript] published online on May 14, 2009
Cardiovascular Research, doi:10.1093/cvr/cvp150
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Chlamydia heat shock protein 60 decreases expression of eNOS in human and porcine coronary artery endothelial cells
1 Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine
2 Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas 77030
* Address correspondence to: Changyi (Johnny) Chen, MD, PhD, Michael E. DeBakey Department of Surgery (R413), Baylor College of Medicine, One Baylor Plaza, Mail stop: BCM390, Houston, TX 77030, Phone: (713) 798-4401, Fax: (713) 798-6633, Email: jchen{at}bcm.tmc.edu
Aims: Clinically, Chlamydia pneumoniae infection and its heat shock protein 60 (cHSP60) may contribute to atherogenesis; however, its underlying mechanisms are largely unknown. The objective of this study was to determine whether cHSP60 could cause endothelial dysfunction in human coronary artery endothelial cells (HCAECs) and porcine coronary arteries.
Methods and Results: When HCAECs were treated with recombinant cHSP60, endothelial nitric oxide synthase (eNOS) mRNA and protein levels, enzyme activities, cellular NO levels, mRNA stability and promoter activities were significantly decreased. Superoxide anion production was significantly increased due to the inhibition of mitochondrial membrane potential and catalase and superoxide dismutase (SOD) activities as well as activation of NADPH oxidase. Antioxidants seleno-L-methionine (SeMet) or SOD mimetic MnTBAP effectively blocked cHSP60-induced eNOS downregulation. In addition, cHSP60 activated mitogen-activated protein kinases (MAPKs) including p38, c-Jun-N-terminal kinase/stress-activated protein kinase and extracellular signal-regulated kinases. Specific chemical inhibitors or their dominant negative mutant forms of these MAPKs effectively blocked cHSP60-induced eNOS downregulation. cHSP60-induced eNOS downregulation and oxidative stress were also demonstrated in porcine coronary artery rings in vitro. Functionally, endothelium-dependent vasorelaxation was significantly reduced in cHSP60-treated vessels.
Conclusions: cHSP60 directly induces eNOS downregulation through oxidative stress and MAPK activation in both HCAECs and porcine coronary arteries, thereby causing endothelial dysfunction.
KEYWORDS Chlamydia pneumonia; heat shock protein 60; endothelial nitric oxide synthase; superoxide anion; MAPK; oxidative stress; antioxidant; SeMet; MnTBAP; atherosclerosis
Time for primary review: 21 Days