title: Activation of PKC-epsilon and ERK1/2 participates in shear-induced endothelial MCP-1 expression that is repressed by nitric oxide.
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.
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Chih-Wen
authors.initials: CW
authors.lastname: Ni
authors.forename: Danny L
authors.initials: DL
authors.lastname: Wang
authors.forename: Sheng-Chieh
authors.initials: SC
authors.lastname: Lien
authors.forename: Jing-Jy
authors.initials: JJ
authors.lastname: Cheng
authors.forename: Yuen-Jen
authors.initials: YJ
authors.lastname: Chao
authors.forename: Hsyue-Jen
authors.initials: HJ
authors.lastname: Hsieh
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000235:genetics; D004730:Endothelium, Vascular / Q000201:enzymology / Q000378:metabolism*; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism / Q000502:physiology; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D009569:Nitric Oxide / Q000502:physiology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D051571:Protein Kinase C-alpha; D051744:Protein Kinase C-epsilon; D015398:Signal Transduction; D013314:Stress, Mechanical
chemical_list: D018932:Chemokine CCL2; D009569:Nitric Oxide; C496628:PRKCA protein, human; C497255:PRKCE protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D051744:Protein Kinase C-epsilon; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases