Activation of PKC-epsilon and ERK1/2 participates in shear-induced endothelial MCP-1 expression that is repressed by nitric oxide

Citation:

Ni CW, Wang DL, Lien SC, Cheng JJ, Chao YJ, Hsieh HJ. Activation of PKC-epsilon and ERK1/2 participates in shear-induced endothelial MCP-1 expression that is repressed by nitric oxide. J Cell Physiol 2003;195:428-34.

Abstract:

Vascular endothelial cells (ECs) continuously experience hemodynamic shear stress generated from blood flow. Previous studies have demonstrated that shear stress modulates monocyte chemotactic protein-1 (MCP-1) expression in ECs. This study explored the roles of protein kinase C (PKC), extracellular signal-regulated protein kinase (ERK1/2), and nitric oxide (NO) in sheared-induced MCP-1 expression in ECs. The activation of PKC-alpha and PKC-epsilon isoforms was observed in ECs exposed to shear stress. The use of an inhibitor (calphostin C) to PKC-alpha and PKC-epsilon decreased ERK1/2 activation and MCP-1 induction by shear, whereas an inhibitor (Go6976) to PKC-alpha did not affect ERK1/2 activation or MCP-1 induction. Inhibition of ERK1/2 activation by PD98059 blocked MCP-1 induction. Transfection of ECs with an antisense to PKC-epsilon abolished the shear inducibility of MCP-1 promoter. These results demonstrate that PKC-epsilon and ERK1/2 participate in shear-induced MCP-1 expression. We also examined the regulatory role of NO in MCP-1 expression. An NO donor (NOC18) suppressed shear-induced activation of PKC-epsilon and ERK1/2, and also repressed MCP-1 induction. Consistently, overexpression of endothelial nitric oxide synthase (eNOS) to enhance the endogenous generation of NO in ECs decreased the activation of PKC-epsilon and ERK1/2, and also inhibited MCP-1 expression. Taken together, these findings suggest that PKC-epsilon and ERK1/2 are critical in the signaling pathway(s) leading to the MCP-1 expression induced by shear stress. Additionally, this study indicates that NO, by repressing PKC-epsilon activity and ERK pathway activation, attenuates shear-induced MCP-1 expression.

Notes:

Ni, Chih-WenWang, Danny LLien, Sheng-ChiehCheng, Jing-JyChao, Yuen-JenHsieh, Hsyue-JenengResearch Support, Non-U.S. Gov't2003/04/22 05:00J Cell Physiol. 2003 Jun;195(3):428-34.