Tchekneva E, Quertermous T, Christman B W, Lawrence M L, Meyrick B
Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2650, USA.
J Clin Invest. 1998 Mar 15;101(6):1389-97. doi: 10.1172/JCI622.
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.
我们研究了对照绵羊以及在空气诱导的慢性肺动脉高压（CPH）结构和功能变化发展过程中的动物的主肺动脉、肺动脉中部区域和外周肺组织中前内皮素-1（ppET-1）基因的表达情况。在连续空气栓塞（CAE）第1、4、8和12天对肺淋巴液中的ET-1进行测量（n = 7），结果显示与对照组（n = 4）相比，从第4天起ET-1显著增加。使用绵羊特异性引物建立了用于ppET-1基因表达的半定量逆转录PCR方法。对照绵羊肺动脉中部区域的ppET-1转录本（22.9±2.3 ng cDNA当量）明显少于主肺动脉和肺组织（分别为736.0±263.7和705.5±125.7）。从对照绵羊的主肺动脉和肺动脉中部区域分离出的平滑肌细胞（SMC）证实了这些发现，并且显示主肺动脉中的细胞内ET-1合成水平高于肺动脉中部区域。在CAE过程中基因表达的差异持续存在。在主肺动脉和肺组织中，ppET-1转录本降至对照组的<1%。然而，肺动脉中部区域的转录本呈逐渐增加趋势。肺动脉中部区域的SMC与ET-1加TGF-β共同孵育导致细胞内大ET-1增加，主肺动脉的SMC减少。我们得出结论，主肺动脉和肺动脉中部区域的SMC在表型上存在差异，并表明在空气诱导的CPH发展过程中，ET-1和TGF-β的局部合成以及肺淋巴液中ET-1水平的升高调节了动脉SMC中ppET-1基因的表达和合成。
