title: Mechanisms of MAPK activation by bradykinin in vascular smooth muscle cells.
abstract: Vascular smooth muscle cell (VSMC) proliferation is a prominent feature of the atherosclerotic process occurring after endothelial injury. A vascular wall kallikrein-kinin system has been described. The contribution of this system to vascular disease is undefined. In the present study we characterized the signal transduction pathway leading to mitogen-activated protein kinase (MAPK) activation in response to bradykinin (BK) in VSMC. Addition of 10(-10)-10(-7) M BK to VSMC resulted in a rapid and concentration-dependent increase in tyrosine phosphorylation of several 144- to 40-kDa proteins. This effect of BK was abolished by the B(2)-kinin receptor antagonist HOE-140, but not by the B(1)-kinin receptor antagonist des-Arg(9)-Leu(8)-BK. Immunoprecipitation with anti-phosphotyrosine antibodies followed by immunoblot revealed that 10(-9) M BK induced tyrosine phosphorylation of focal adhesion kinase (p125(FAK)). BK (10(-8) M) promoted the association of p60(src) with the adapter protein growth factor receptor binding protein-2 and also induced a significant increase in MAPK activity. Pertussis and cholera toxins did not inhibit BK-induced MAPK tyrosine phosphorylation. Protein kinase C downregulation by phorbol 12-myristate 13-acetate and/or inhibitors to protein kinase C, p60(src) kinase, and MAPK kinase inhibited BK-induced MAPK tyrosine phosphorylation. These findings provide evidence that activation of the B(2)-kinin receptor in VSMC leads to generation of multiple second messengers that converge to activate MAPK. The activation of this crucial kinase by BK provides a strong rationale to investigate the mitogenic actions of BK on VSMC proliferation in disease states of vascular injury.
authors.affiliation: Department of Medicine, Medical University of South Carolina and Ralph H. Johnson Department of Veterans Affairs Medical Center, Charleston, South Carolina 29425, USA.
authors.forename: V
authors.initials: V
authors.lastname: Velarde
authors.forename: M E
authors.initials: ME
authors.lastname: Ullian
authors.forename: T A
authors.initials: TA
authors.lastname: Morinelli
authors.forename: R K
authors.initials: RK
authors.lastname: Mayfield
authors.forename: A A
authors.initials: AA
authors.lastname: Jaffa
mesh_terms: D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000187:drug effects* / Q000378:metabolism*; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000494:pharmacology; D003593:Cytoplasm / Q000201:enzymology; D004789:Enzyme Activation / Q000502:physiology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018002:Receptors, Bradykinin / Q000502:physiology; D014443:Tyrosine / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D018002:Receptors, Bradykinin; D010566:Virulence Factors, Bordetella; D014443:Tyrosine; D002772:Cholera Toxin; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D001920:Bradykinin