Endothelin-1 induces gene expression through stimulation of endothelin type A receptors in normal rat kidney cells.
RNA blots of total cellular RNA isolated from quiescent and endothelin (ET-1)-stimulated normal rat kidney (NRK) cells demonstrated that ET-1 induced the expression of c-jun, jun B, and c-fos mRNA in a time-dependent manner with maximal expression of mRNA by 1 hr after the addition of ET-1. Five hundred picomolar ET-1 was sufficient to induce maximal mRNA expression. These data agreed with saturation experiments which demonstrated that maximal binding of [125I]ET-1 was achieved at concentrations greater than 100 pM. The Kd and Bmax values for [125I]ET-1 binding to NRK membranes were 20.5 pM and 22.2 fmol/mg protein, respectively. Competition experiments for the binding of [125I]ET-1 to NRK membranes demonstrated that ET-1 was a more potent inhibitor (Ki = 0.047 nM) than ET-3 (Ki = 10.8 nM). No specific binding of [125I]ET-3 (40 or 500 pM) to NRK membranes could be observed. The expression of c-jun, jun B, and c-fos mRNA was inhibited by the endothelin type A receptor (ET)-selective antagonist, BQ-123. Thus, these data demonstrate that ET-1 mediates the expression of immediate response gene mRNA in NRK cells via the ETA receptor. ET-1 stimulation of NRK cells also upregulated EGF receptors, providing a possible mechanism for ET-1 complementation of epidermal growth factor (EGF) mitogenicity in NRK cells.
Yumet
G
G
Department of Microbiology and Immunology, Temple University Medical School, Philadelphia, Pennsylvania 19140, USA.
Chin
M H
MH
Carey
B
B
Soprano
K J
KJ
Lipson
K E
KE
D000818:Animals; D002478:Cells, Cultured; D065128:Endothelin Receptor Antagonists; D016232:Endothelins / Q000494:pharmacology*; D066246:ErbB Receptors / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects*; D016762:Genes, fos; D016758:Genes, jun; D066298:In Vitro Techniques; D007668:Kidney / Q000166:cytology; D010456:Peptides, Cyclic / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017466:Receptors, Endothelin / Q000378:metabolism*; D015398:Signal Transduction
D065128:Endothelin Receptor Antagonists; D016232:Endothelins; D010456:Peptides, Cyclic; D012333:RNA, Messenger; D017466:Receptors, Endothelin; D066246:ErbB Receptors; C072247:cyclo(Trp-Asp-Pro-Val-Leu)