title: Atrial natriuretic peptide-C receptor-induced attenuation of adenylyl cyclase signaling activates phosphatidylinositol turnover in A10 vascular smooth muscle cells.
abstract: Atrial natriuretic peptide (ANP)-C receptor activation has been shown to inhibit adenylyl cyclase (AC) activity as well as to stimulate phospholipase C (PLC) signaling pathways. The present studies were undertaken to investigate whether ANP-C receptor-mediated decreased cAMP levels contribute to the activation of PLC signaling. C-ANP(4-23) [des(Gln(18),Ser(19), Glu(20),Leu(21),Gly(22))ANP(4-23)-NH(2)], a ring-deleted peptide of ANP that interacts specifically with ANP-C receptor, stimulated inositol 1,4,5-tris-phosphate (IP(3)) production (PLC activity) in A10 vascular smooth muscle cells in a concentration- and time-dependent manner. The maximal stimulation observed was about 75% at 2 h of treatment, with an apparent EC(50) of about 20 to 30 nM. Pertussis toxin treatment of the cells completely abolished the C-ANP(4-23)-mediated stimulation of IP(3) production. Forskolin (FSK), a stimulator of adenylyl cyclase, dibutyryl cAMP (db cAMP), and isoproterenol (ISO), a beta-adrenergic agonist that stimulates adenylyl cyclase activity and cAMP levels, inhibited IP(3) production by about 35, 30, and 50%, respectively, whereas dideoxyadenosine (DDA), an inhibitor of adenylyl cyclase activity, and oxotremorine stimulated IP(3) production by about 90 and 80%, respectively, in these cells, suggesting a functional interaction between these two signaling pathways. Treatment of the cells with antisense oligonucleotide of ANP-C receptor that attenuated ANP-C receptor-mediated inhibition of adenylyl cyclase resulted in a complete attenuation of C-ANP(4-23)-induced stimulation of IP(3) formation, whereas FSK, db cAMP, and ISO-mediated decrease and oxotremorine and endothelin-1 (ET-1)-induced increase in IP(3) production was not affected by this treatment. Furthermore, C-ANP(4-23)-induced increase in IP(3) formation was significantly potentiated by DDA and inhibited by FSK and db cAMP, whereas ET-1-induced increase in IP(3) production was not affected by FSK. In addition, N-[2-(4-bromocinnamylamino)ethyl]-5-isoquinoline (H-89), an inhibitor of protein kinase A, completely abolished C-ANP(4-23) and not ET-1-induced stimulation of IP(3) production. These results indicate that ANP-C receptor activation by C-ANP(4-23) and resulting decrease in cAMP levels may be responsible for the activation of phosphatidylinositol (PI) turnover signaling, suggesting a cross-talk between ANP-C receptor-mediated adenylyl cyclase and PLC signaling pathways.
authors.affiliation: Department of Physiology, Faculty of Medicine, University of Montreal, C.P. 6128, succ. Centre-ville, Montreal, Quebec, Canada, H3C 3J7. anandsrm@physio.umontreal.ca
authors.forename: Rima
authors.initials: R
authors.lastname: Mouawad
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Madhu B
authors.initials: MB
authors.lastname: Anand-Srivastava
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism / Q000494:pharmacology; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D016373:DNA, Antisense / Q000494:pharmacology; D016048:Dideoxyadenosine / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000378:metabolism; D051381:Rats; D020239:Receptor Cross-Talk; D017461:Receptors, Atrial Natriuretic Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D016373:DNA, Antisense; D010446:Peptide Fragments; D010716:Phosphatidylinositols; C065367:atrial natriuretic factor (4-23)NH2, de-Gln(18)-de-Ser(19)-de-Gly(20,22)-de-Leu(21)-; D005576:Colforsin; D016048:Dideoxyadenosine; D015544:Inositol 1,4,5-Trisphosphate; D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP; D010738:Type C Phospholipases; D000262:Adenylyl Cyclases; D006162:Guanylate Cyclase; D017461:Receptors, Atrial Natriuretic Factor; C073616:atrial natriuretic factor receptor C