Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
J Cell Physiol. 2013 Feb;228(2):322-9. doi: 10.1002/jcp.24132.
Human pulmonary arterial smooth muscle cells (PASMC) were isolated from elastic pulmonary arteries dissected from lungs of individuals with and without pulmonary arterial hypertension (PAH). Reflecting increased smooth muscle constriction in cells from PAH subject, Ca(2+) influx in response to endothelin-1 (ET-1) increased in all the PAH PASMC populations relative to the normal donor control cells. The ETA receptor mRNA levels remained unchanged, whereas the ETB receptor mRNA levels decreased in both heritable and idiopathic PAH-derived PASMC. All the PASMC populations expressed considerably higher ETA compared to ETB receptor number. Both ETA and ETB receptor numbers were reduced in bone morphogenetic protein receptor type II (BMPR2) mutation PAH. ETB receptors showed a particular reduction in number. Phospho-antibody array analysis of normal and BMPR2 deletion PASMC illustrated ERK and Akt activation to be the most prominent and to be taking place principally through ETB receptors in normal PASMC, but primarily through ETA receptors in PASMC from BMPR2 PAH subjects. Additionally in the PAH cells the total relative ET-1 signal response was markedly reduced. Western analysis from the BMPR2 PASMC duplicated the array results, whereas PASMC from iPAH subjects showed variability with most samples continuing to signal through ETB. In sum, these results indicate that generally both receptors are reduced in PAH particularly ETB, and that ETB signaling through protein kinases becomes markedly reduced in BMPR2 PASMC, while it continues in IPAH. Importantly, the data suggest that caution must be taken when applying ET-1 receptor antagonist therapy to PAH patients.
人肺动脉平滑肌细胞（PASMC）从有和没有肺动脉高压（PAH）的个体的弹性肺血管中分离出来。反映出来自 PAH 患者的平滑肌收缩增加，内皮素-1（ET-1）引起的 Ca（2+）内流在所有 PAH PASMC 群体中相对于正常供体对照细胞增加。ETA 受体 mRNA 水平保持不变，而 ETB 受体 mRNA 水平在遗传性和特发性 PAH 来源的 PASMC 中均降低。所有 PASMC 群体表达的 ETA 受体数量明显高于 ETB 受体数量。BMPR2 突变 PAH 中的 ETB 和 ETB 受体数量均减少。ETB 受体数量特别减少。正常和 BMPR2 缺失 PASMC 的磷酸化抗体阵列分析表明 ERK 和 Akt 激活是最显著的，并且主要通过正常 PASMC 中的 ETB 受体发生，但主要通过 BMPR2 PAH 患者的 PASMC 中的 ETA 受体发生。此外，在 PAH 细胞中，总相对 ET-1 信号反应明显降低。BMPR2 PASMC 的 Western 分析复制了阵列结果，而 iPAH 患者的 PASMC 显示出变异性，大多数样本继续通过 ETB 发出信号。总之，这些结果表明，一般来说，两种受体在 PAH 中都减少，特别是 ETB，并且在 BMPR2 PASMC 中，通过蛋白激酶的 ETB 信号显著减少，而在 IPAH 中则继续存在。重要的是，数据表明，在向 PAH 患者应用 ET-1 受体拮抗剂治疗时必须谨慎。
