title: Interaction of atrial natriuretic factor and endothelin-1 signals through receptor guanylate cyclase in pulmonary artery endothelial cells.
abstract: The endothelial cell has a unique intrinsic feature: it produces a most potent vasopressor peptide hormone, endothelin (ET-1), yet it also contains a signaling system of an equally potent hypotensive hormone, atrial natriuretic factor (ANF). This raises two related curious questions: does the endothelial cell also contain an ET-1 signaling system? If yes, how do the two systems interact with each other? The present investigation was undertaken to determine such a possibility. Bovine pulmonary artery endothelial (BPAE) cells were chosen as a model system. Identity of the ANF receptor guanylate cyclase was probed with a specific polyclonal antibody to the 180 kDa membrane guanylate cyclase (mGC) ANF receptor. A Western-blot analysis of GTP-affinity-purified endothelial cell membrane proteins recognized a 180 kDa band; the same antibody inhibited the ANF-stimulated guanylate cyclase activity; the ANF-dependent rise of cyclic GMP in the intact cells was dose-dependent. By affinity cross-linking technique, a predominant 55 kDa membrane protein band was specifically labeled with [125I]ET-1. ET-1 treatment of the cells showed a migration of the protein kinase C (PKC) activity from cytosol to the plasma membrane; ET-1 inhibited the ANF-dependent production of cyclic GMP in a dose-dependent fashion with an EC50 of 100 nM. This inhibitory effect was duplicated by phorbol 12-myristate 13-acetate (PMA), a known PKC-activator. The EC50 of PMA was 5 nM. A PKC inhibitor, 1-(5-isoquinolinyl-sulfonyl)-2-methyl piperazine (H-7), blocked the PMA-dependent attenuation of ANF-dependent cyclic GMP formation. These results demonstrate that the 180 kDa mGC-coupled ANF and ET-1 signaling systems coexist in endothelial cells and that the ET-1 signal negates the ANF-dependent guanylate cyclase activity and cyclic GMP formation. Furthermore, these results support the paracrine and/or autocrine role of ET-1.
authors.affiliation: Unit of Regulatory and Molecular Biology, Pennsylvania College of Optometry, Philadelphia 19141.
authors.forename: R B
authors.initials: RB
authors.lastname: Marala
authors.forename: T
authors.initials: T
authors.lastname: Duda
authors.forename: R K
authors.initials: RK
authors.lastname: Sharma
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001692:Biological Transport; D002417:Cattle; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D016232:Endothelins / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D006162:Guanylate Cyclase / Q000378:metabolism*; D006801:Humans; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011651:Pulmonary Artery; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D016232:Endothelins; D009320:Atrial Natriuretic Factor; D011493:Protein Kinase C; D006162:Guanylate Cyclase; D017461:Receptors, Atrial Natriuretic Factor; D006152:Cyclic GMP