title: Small cytoplasmic domain peptides of natriuretic peptide receptor-C attenuate cell proliferation through Gialpha protein/MAP kinase/PI3-kinase/AKT pathways.
abstract: The present studies were undertaken to investigate the effect of C-atrial natriuretic peptide (ANP)(4-23) and several peptide fragments containing 12 amino acids from different regions of the cytoplasmic domain of natriuretic peptide receptor (NPR)-C on cell proliferation in the absence or presence of angiotensin (ANG) II, endothelin (ET)-1, and arginine vasopressin (AVP) in A-10 vascular smooth muscle cells (VSMC). The peptide fragments used have either complete G(i) activator sequences K(461)-H(472) (peptide 1) and H(481)-H(492) (peptide 3) or partial G(i) activator sequences R(469)-K(480) (peptide 2) and I(465)-H(472) (peptide Y) with truncated COOH or NH(2) terminus, respectively. The other peptide used had no structural specificity (Q(473)-K(480), peptide X) or was the scrambled peptide control for peptide 1 (peptide Z). ANG II, ET-1 and AVP significantly stimulated DNA synthesis in these cells as determined by [(3)H]thymidine incorporation that was inhibited by peptides 1, 2, and 3 and not by peptides X, Y, and Z in a concentration-dependent manner, with an apparent K(i) between 1 and 10 nM. In addition, C-ANP(4-23), which interacts with NPR-C, also inhibited DNA synthesis stimulated by vasoactive peptides; however, the inhibition elicited by C-ANP(4-23) was not additive with the inhibition elicited by peptide 1. On the other hand, basal DNA synthesis in these cells was not inhibited by C-ANP(4-23) or the peptide fragments. Furthermore, vasoactive peptide-induced stimulation of DNA synthesis was inhibited by PD-98059 and wortmannin, and this inhibition was potentiated by peptide 1. In addition, peptide 1 also inhibited vasoactive peptide-induced phosphorylation of ERK1/2 and AKT and enhanced expression of G(i)alpha proteins. These data suggest that C-ANP(4-23) and small peptide fragments containing 12 amino acids irrespective of the region of the cytoplasmic domain of NPR-C inhibit proliferative responses of vasoactive peptides through G(i)alpha protein and MAP kinase/phosphatidylinositol 3-kinase/AKT pathways.
authors.affiliation: Dept. of Physiology, Faculty of Medicine, University of Montreal, Montreal, QC, Canada H3C 3J7.
authors.forename: Shehla
authors.initials: S
authors.lastname: Hashim
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Madhu B
authors.initials: MB
authors.lastname: Anand-Srivastava
mesh_terms: D000595:Amino Acid Sequence; D000730:Androstadienes / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002460:Cell Line; D049109:Cell Proliferation; D019332:Endothelin-1 / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology*; D037342:Pertussis Toxin / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D019332:Endothelin-1; D005419:Flavonoids; D010446:Peptide Fragments; D047428:Protein Kinase Inhibitors; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; C065367:atrial natriuretic factor (4-23)NH2, de-Gln(18)-de-Ser(19)-de-Gly(20,22)-de-Leu(21)-; D001127:Arginine Vasopressin; D009320:Atrial Natriuretic Factor; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D017461:Receptors, Atrial Natriuretic Factor; C073616:atrial natriuretic factor receptor C; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin