title: Regulation of VASP phosphorylation in cardiac myocytes: differential regulation by cyclic nucleotides and modulation of protein expression in diabetic and hypertrophic heart.
abstract: Vasodilator-stimulated phosphoprotein (VASP) is a major substrate for cyclic nucleotide-dependent kinases that has been implicated in cardiac pathology, yet many aspects of VASP's molecular regulation in cardiomyocytes are incompletely understood. In these studies, we explored the role of VASP, both in signaling pathways in isolated murine myocytes, as well as in a model of cardiac hypertrophy in VASP(null) mice. We found that the beta-adrenergic agonist isoproterenol promotes the rapid and reversible phosphorylation of VASP at Ser157 and Ser239. Forskolin and the cAMP analog 8-(4-chlorophenylthio)-cAMP promote a similar pattern of VASP phosphorylation at both sites. The effects of isoproterenol are blocked by atenolol and by compound H-89, an inhibitor of the cAMP-dependent protein kinase. By contrast, phosphorylation of VASP only at Ser239 is seen following activation of particulate guanylate cyclase by atrial natriuretic peptide, or following activation of soluble guanylate cyclase by sodium nitroprusside, or following treatment of myocytes with cGMP analog. We found that basal and isoproterenol-induced VASP phosphorylation is entirely unchanged in cardiomyocytes isolated from either endothelial or neuronal nitric oxide synthase knockout mice. In cardiomyocytes isolated from diabetic mice, only basal VASP phosphorylation is increased, whereas, in cells isolated from mice subjected to ascending aortic constriction (AAC), we found a significant increase in basal VASP expression, along with an increase in VASP phosphorylation, compared with cardiac myocytes isolated from sham-operated mice. Moreover, there is further increase in VASP phosphorylation in cells isolated from hypertrophic hearts following isoproterenol treatment. Finally, we found that VASP(null) mice subjected to transverse aortic constriction develop cardiac hypertrophy with a pattern similar to VASP(+/+) mice. Our findings establish differential receptor-modulated regulation of VASP phosphorylation in cardiomyocytes by cyclic nucleotides. Furthermore, these studies demonstrate for the first time that VASP expression is upregulated in hypertrophied heart.
authors.affiliation: Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Juliano L
authors.initials: JL
authors.lastname: Sartoretto
authors.forename: Benjamin Y
authors.initials: BY
authors.lastname: Jin
authors.forename: Michael
authors.initials: M
authors.lastname: Bauer
authors.forename: Frank B
authors.initials: FB
authors.lastname: Gertler
authors.forename: Ronglih
authors.initials: R
authors.lastname: Liao
authors.forename: Thomas
authors.initials: T
authors.lastname: Michel
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure; D006332:Cardiomegaly / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D015815:Cell Adhesion Molecules / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D003920:Diabetes Mellitus / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism; D006339:Heart Rate; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008840:Microfilament Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism; D009712:Nucleotides, Cyclic / Q000378:metabolism*; D010750:Phosphoproteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D012694:Serine; D000071756:Soluble Guanylyl Cyclase; D013873:Thionucleotides / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D015815:Cell Adhesion Molecules; D020536:Enzyme Activators; D008840:Microfilament Proteins; D009712:Nucleotides, Cyclic; D010750:Phosphoproteins; D047428:Protein Kinase Inhibitors; D011943:Receptors, Adrenergic, beta; D018160:Receptors, Cytoplasmic and Nuclear; D013873:Thionucleotides; D000098662:Vasodilator-Stimulated Phosphoprotein; D009569:Nitric Oxide; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D012694:Serine; D000242:Cyclic AMP; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; C496321:Nos1 protein, mouse; C496315:Nos3 protein, mouse; D017868:Cyclic AMP-Dependent Protein Kinases; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006152:Cyclic GMP