title: Protein kinase C-δ (PKC-δ) and PKC-α mediate Ca(2+)-dependent increases in CNP mRNA in human vascular cells.
abstract: C type natriuretic peptide (CNP) functions as a paracrine/autocrine vasoprotectant. CNP mRNA is up-regulated in human vascular smooth muscle cells (SMC) by PDGF-BB via a protein kinase C (PKC)-dependent pathways, and by general PKC activation with phorbol myristate acetate (PMA). In this report we examine the calcium dependence and isotype specificity of these PKC/CNP pathways. The PKC-δ-specific inhibitor rottlerin blocked the increase in CNP mRNA and immunoreactive CNP following treatment of aortic SMC (AoSMC) with PDGF-BB. A 300-400-fold PMA-induced elevation of CNP transcript levels in AoSMC and a ~40-fold increase in human aortic endothelial cells (HAEC) were reduced by PKC-α- and PKC-δ-, but not PKC-β-specific inhibitors. siRNA silencing of PKC-δ reduced PDGF-, but not PMA-stimulated CNP transcript in SMC. Inhibition of intracellular Ca(2+) mobilization abolished a PMA-stimulated increase in CNP transcript in both SMC and HAEC. The results of this study show that PDGF increases CNP in SMC via a protein kinase C-δ-dependent pathway. In contrast, PMA increases CNP expression using PKC-α- and PKC-δ-pathways in both SMC and HAEC. A 8-10-fold greater PMA-induced increase in CNP transcript in SMC than in HAEC suggests that smooth muscle cells could be selectively targeted for CNP up-regulation by PKC-α- and PKC-δ-activators.
authors.affiliation: Department of Medicine, Division of Endocrinology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Mendonça
authors.forename: Nancy
authors.initials: N
authors.lastname: Koles
authors.forename: Donald F
authors.initials: DF
authors.lastname: Sellitti
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D000077214:Becaplermin; D001578:Benzopyrans / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D020868:Gene Silencing; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D020098:Natriuretic Peptide, C-Type / Q000378:metabolism*; D051571:Protein Kinase C-alpha / Q000378:metabolism*; D051745:Protein Kinase C-delta / Q000378:metabolism*; D020574:Proto-Oncogene Proteins c-sis / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000008:administration & dosage; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000098:Acetophenones; D001578:Benzopyrans; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D020098:Natriuretic Peptide, C-Type; D000077214:Becaplermin; C085746:rottlerin; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium