Bradykinin B2 receptor-mediated proliferation via activation of the Ras/Raf/MEK/MAPK pathway in rat vascular smooth muscle cells.
It has been suggested that bradykinin (BK) plays an important role in regulating neointimal formation after vascular injury. However, implication of BK in the growth of rat vascular smooth muscle cells (VSMCs) is controversial. Therefore, we examined the mitogenic effect of BK on VSMCs associated with activation of mitogen-activated protein kinase (MAPK). Both [(3)H]thymidine incorporation and p42/p44 MAPK phosphorylation were activated by BK in time- and concentration-dependent manners. Pretreatment of these cells with neither pertussis toxin nor cholera toxin attenuated the BK-induced responses. Pretreatment of VSMCs with Hoe 140 (a selective B(2) receptor antagonist), U73122 (an inhibitor of phospholipase C), and BAPTA/AM (an intracellular Ca(2+) chelator) inhibited both [(3)H]thymidine incorporation and p42/p44 MAPK phosphorylation in response to BK. BK-induced [(3)H]thymidine incorporation and p42/p44 MAPK phosphorylation were inhibited by pretreatment of VSMCs with tyrosine kinase inhibitors (genistein and herbimycin A), protein kinase C (PKC) inhibitors (staurosporine, Go-6976, and Ro-318220), an MAPK kinase inhibitor (PD98059), and a p38 MAPK inhibitor (SB203580). Overexpression of the dominant negative mutants, H-Ras-15A and Raf-N4, suppressed p42/p44 MAPK activation induced by BK and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. From these results, we concluded that the mitogenic effect of BK is mediated through activation of the Ras/Raf/MEK/MAPK pathway similar to that of PDGF-BB. BK-mediated MAPK activation was modulated by Ca(2+), PKC, and tyrosine kinase all of which are associated with cell proliferation in rat cultured VSMCs.
Yang
Chuen-Mao
CM
Department of Physiology/Pharmacology, College of Medicine, Chang Gung University, Kweishan, Taoyuan, Taiwan, ROC. chuenmao@mail.cgu.edu.tw
Chien
Chin-Sung
CS
Ma
Yuun-Hwa
YH
Hsiao
Li-Der
LD
Lin
Ching-Hsuan
CH
Wu
Chou- Bing
C
D000818:Animals; D015153:Blotting, Western; D002455:Cell Division; D002460:Cell Line; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D037342:Pertussis Toxin / Q000494:pharmacology; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D020033:Protein Isoforms; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D051381:Rats; D043782:Receptor, Bradykinin B2 / Q000502:physiology*; D013936:Thymidine / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D018631:ras Proteins / Q000378:metabolism
D004791:Enzyme Inhibitors; D020033:Protein Isoforms; D043782:Receptor, Bradykinin B2; D004247:DNA; D002772:Cholera Toxin; D037342:Pertussis Toxin; D011505:Protein-Tyrosine Kinases; D019908:Proto-Oncogene Proteins c-raf; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D018631:ras Proteins; D013936:Thymidine