Heat-shock protein 60 of Porphyromonas gingivalis may induce dysfunction of human umbilical endothelial cells via regulation of endothelial-nitric oxide synthase and vascular endothelial-cadherin

Abstract

Accumulating evidence has established that periodontitis was an independent risk factor for coronary heart disease (CAD). <i>Porphyromonus gingivalis</i> (<i>P. gingivalis</i>), a major periodontal pathogen, has already been shown to have a significant role in the inflammatory response of CAD <i>in vivo</i>. The aim of the present study was to identify whether <i>P. gingivalis</i> heat-shock protein 60 (HSP60) induced the dysfunction of human umbilical vein endothelial cells (HUVECs) <i>in vitro</i>. HUVECs were stimulated with a range of <i>P. gingivalis</i> HSP60 concentrations (1, 10 and 100 ng/l) at different time-points. The levels of vascular endothelial (VE)-cadherin, endothelial nitric oxide synthase (eNOS) and cysteinyl aspartate-specific protease-3 (caspase-3) were measured using western blot analysis. The apoptotic rate of HUVECs was detected using flow cytometry. <i>P. gingivalis</i> HSP60 at a concentration of 10 ng/l significantly decreased the expression levels of VE-cadherin and eNOS protein at 24 h stimulation, whereas no difference in these proteins was identified following a low dose of <i>P. gingivalis</i> HSP60 (1 ng/l). <i>P. gingivalis</i> HSP60 at 100 ng/l significantly downregulated the expression levels of VE-cadherin and eNOS protein at 12 h in HUVECs. However, the cleavage of caspase-3 showed an opposing change at different concentrations. Consistently, <i>P. gingivalis</i> HSP60 induced apoptosis of HUVECs in a concentration-dependent manner. These results indicated that <i>P. gingivalis</i> HSP60 may induce dysfunction and apoptosis in HUVECs via downregulating the expression levels of VE-cadherin and eNOS, and promoting the cleavage of caspase-3.