Endothelin receptor subtype B mediates autoinduction of endothelin-1 in rat mesangial cells.
Autoinduction of endothelin-1 (ET-1) has been suggested to be involved in the profound and long-lasting effects of ET-1. We examined mechanisms that underlie autoinduction of ET-1 in cultured rat glomerular mesangial cells. Incubation of mesangial cells with ET-1 resulted in an immediate and dose-dependent stimulation of preproET-1 mRNA expression as assessed by polymerase chain reaction coupled with reverse transcription. Within 1 h of exposure to ET-1 (10(-7) M), preproET-1 mRNA expression was increased to a maximal level of 465 +/- 43% of the control value (p < 0.01), which was accompanied by significant stimulation of production of the immunoreactive ET-1 peptide. Nuclear run-off analysis revealed increases in the transcriptional rate of preproET-1 mRNA to 239 and 175% above the control values at 1 and 3 h of ET-1 stimulation, respectively. ET-1 also increased the stability of preproET-1 mRNA, resulting in an mRNA half-life of 60 min from 20 min seen in non-stimulated cells. Addition of an ETB-specific antagonist, RES701-1, at > 10(-9) M abolished ET-1 stimulation of preproET-1 mRNA (p < 0.001), whereas an ETA-specific antagonist, BQ123, was without effects (up to 10(-5) M). The ETB agonist, sarafotoxin S6c (10(-7) M), significantly stimulated preproET-1 mRNA expression to 201 +/- 14% above controls (p < 0.01), and effect that was lessened significantly by RES701-1 (p < 0.05). RES701-1 abolished the ET-1-induced production of the ET-1 peptide (p < 0.001). Taken together, we demonstrates that in mesangial cells, autoinduction of ET-1 occurs through the ETB receptor subtype via increases in both preproET-1 transcription and mRNA stability.
Iwasaki
S
S
Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2584.
Homma
T
T
Matsuda
Y
Y
Kon
V
V
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D019332:Endothelin-1; D016232:Endothelins / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D005920:Glomerular Mesangium / Q000378:metabolism*; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000494:pharmacology; D011498:Protein Precursors / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017466:Receptors, Endothelin / Q000502:physiology*; D014158:Transcription, Genetic
D019332:Endothelin-1; D016232:Endothelins; D010456:Peptides, Cyclic; D011498:Protein Precursors; D012333:RNA, Messenger; D017466:Receptors, Endothelin; C087120:RES 701-1; C072247:cyclo(Trp-Asp-Pro-Val-Leu)