Regional variability in preproEndothelin-1 gene expression in sheep pulmonary artery and lung during the onset of air-induced chronic pulmonary hypertension. Participation Of arterial smooth muscle cells.
We investigated preproendothelin-1 (ppET-1) gene expression in the main and midregion pulmonary artery, and peripheral lung from control sheep and from animals during the development of the structural and functional changes of air-induced chronic pulmonary hypertension (CPH). Measurement of ET-1 in lung lymph (n = 7) at 1, 4, 8, and 12 d of continuous air embolization (CAE) showed a significant increase from day 4 compared with controls (n = 4). A semiquantitative reverse transcription PCR for ppET-1 gene expression was developed using ovine-specific primers. Control sheep showed strikingly fewer ppET-1 transcripts in the midregion (22.9+/-2.3 ng cDNA equivalents) than in the main pulmonary artery and lung (736.0+/-263.7 and 705.5+/-125.7, respectively). Smooth muscle cells (SMC) isolated from the main and midregion artery of control sheep confirmed these findings and showed higher levels of intracellular ET-1 synthesis in the main versus the midregion artery. Differences in gene expression persisted during CAE. In main pulmonary artery and lung, ppET-1 transcripts fell to < 1% of controls. However, transcripts in the midregion artery showed a gradual increase. Coincubation of SMC from the midregion with ET-1 plus TGF-beta resulted in an increase in intracellular big ET-1 and a decrease in SMC from the main artery. We conclude that SMC from the main and midregion pulmonary artery are phenotypically different and suggest that local synthesis of ET-1 and TGF-beta, and increased levels of ET-1 in lung lymph, regulate ppET-1 gene expression and synthesis in arterial SMC during the development of air-induced CPH.
Tchekneva
E
E
Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2650, USA.
Quertermous
T
T
Christman
B W
BW
Lawrence
M L
ML
Meyrick
B
B
D000818:Animals; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D019332:Endothelin-1 / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D016232:Endothelins / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D006439:Hemodynamics; D006976:Hypertension, Pulmonary / Q000235:genetics* / Q000378:metabolism*; D017403:In Situ Hybridization; D008168:Lung / Q000378:metabolism*; D008196:Lymph / Q000378:metabolism; D009130:Muscle, Smooth / Q000166:cytology / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism*; D011651:Pulmonary Artery / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012756:Sheep; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000494:pharmacology
D018076:DNA, Complementary; D019332:Endothelin-1; D016232:Endothelins; D011498:Protein Precursors; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta