Effects of endothelin-1 on release of adrenomedullin and C-type natriuretic peptide from individual human vascular endothelial cells.
Regulation of cardiovascular system activity involves complex interactions amongst numerous factors. Three of these vasoactive factors are adrenomedullin, C-type natriuretic peptide (CNP) and endothelin-1 (ET-1), each of which is claimed to have important local effects. To investigate paracrine/autocrine regulation of the secretion of these peptides we used a cell immunoblot method. We postulated that basal release of adrenomedullin and CNP by endothelial cells is modulated by ET-1. Dispersed human aortic endothelial cells were attached to a protein binding membrane and incubated for 1 or 4 h with control medium or with ET-1, endothelin receptor antagonists or antibody to ET-1, and then submitted to immunohistochemical staining. Peptides (adrenomedullin, CNP and ET-1) within individual cells were stained, as was peptide secreted and adjacent to the cell. It was demonstrated that adrenomedullin, CNP and ET-1 can be contained within the same cell. In addition, we observed that individual endothelial cells can secrete all three peptides. The endothelin ET-A/ET-B receptor antagonist, bosentan, the ET-B receptor antagonist, BQ-788, and anti-ET-1 serum decreased the percentage of endothelial cells that secreted adrenomedullin and CNP relative to control. Conversely, the addition of ET-1 induced an increase in the number of endothelial cells that secreted adrenomedullin and CNP. These results provide strong evidence that endogenous ET-1, from human vascular endothelial cells, acts in a paracrine/autocrine manner to modulate the basal release of adrenomedullin and CNP. Our observations of this modulation suggest that vascular endothelial cells of humans constitute an important component of a self-responsive vasoregulatory system.
Evans
J J
JJ
University Department of Obstetrics and Gynaecology, Christchurch School of Medicine and Health Sciences, Christchurch Women's Hospital, Private Bag 4711, Christchurch, New Zealand. john.evans@chmeds.ac.nz
Youssef
A H
AH
Yandle
T G
TG
Lewis
L K
LK
Nicholls
M G
MG
D053607:Adrenomedullin; D001011:Aorta; D000077300:Bosentan; D002478:Cells, Cultured; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000276:immunology / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D015151:Immunoblotting / Q000379:methods; D020098:Natriuretic Peptide, C-Type / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D010455:Peptides / Q000378:metabolism*; D010880:Piperidines / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology
D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D007106:Immune Sera; D009842:Oligopeptides; D010455:Peptides; D010880:Piperidines; D013449:Sulfonamides; D020098:Natriuretic Peptide, C-Type; D053607:Adrenomedullin; C086539:BQ 788; D000077300:Bosentan