Division of Cardiovascular Medicine, Department of Clinical Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
Division of Cardiovascular Medicine, Department of Clinical Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
Life Sci. 2016 Aug 15;159:116-120. doi: 10.1016/j.lfs.2016.03.044. Epub 2016 Mar 26.
Vascular remodeling results from aberrations in the balance between cell proliferation and death, which is seen in the obstructive vasculature of pulmonary arterial hypertension (PAH). Endothelin (ET)-1 has a potent proliferative activity on vascular smooth muscle cells, and ET receptor inhibitors are used to treat PAH; however, it remains unclear whether ET receptor inhibition contributes to the apoptosis of pulmonary arterial smooth muscle cells (PASMCs), another cause of pulmonary vascular remodeling.
Cultured human PASMCs were treated with the ETA receptor antagonist BQ-123 (100μM), or the ETB antagonist A-192621 (1-100μM) or BQ-788 (1-100μM) for 48h. The cells were then incubated for another 24h with or without doxorubicin (DOX, 1μM), an anthracyclin antitumor antibiotic that promotes p53-mediated apoptosis. Cell viability and apoptosis were evaluated by MTT assays, caspase-3/7 activity assays, and Western blots for cleaved caspase-3 expression.
The viability of PASMCs was significantly decreased by A-192621 and BQ-788, in a dose-dependent manner. A-192621 and BQ-788 significantly increased the caspase-3/7 activity and cleaved caspase-3 expression in PASMCs. The PASMCs' susceptibility to DOX-induced apoptosis was significantly higher in the presence of A-192621 and BQ-788 than with vehicle. However, BQ-123 did not affect these parameters.
Blockade of the ETB receptor increases the extent of apoptosis and susceptibility to DOX-induced apoptosis in PASMCs. Apoptosis caused by ETB receptor blockade in PASMCs may be one of the mechanisms by which vascular remodeling is reduced in ET receptor inhibitor-based PAH treatments.
血管重构是由于细胞增殖和死亡之间的平衡失调引起的，这种情况可见于肺动脉高压（PAH）的阻塞性血管中。内皮素（ET）-1对血管平滑肌细胞具有很强的增殖活性，ET 受体抑制剂被用于治疗 PAH；然而，ET 受体抑制是否有助于肺动脉平滑肌细胞（PASMC）的凋亡（另一种导致肺血管重构的原因）仍不清楚。
用 ETA 受体拮抗剂 BQ-123（100μM）或 ETB 拮抗剂 A-192621（1-100μM）或 BQ-788（1-100μM）处理培养的人 PASMC 48 小时。然后，将细胞在有无阿霉素（DOX，1μM）的情况下再孵育 24 小时，DOX 是一种促 p53 介导凋亡的蒽环类抗肿瘤抗生素。通过 MTT 测定法、caspase-3/7 活性测定法和 cleaved caspase-3 表达的 Western blot 评估细胞活力和细胞凋亡。
A-192621 和 BQ-788 呈剂量依赖性显著降低 PASMC 的活力。A-192621 和 BQ-788 显著增加 PASMC 中的 caspase-3/7 活性和 cleaved caspase-3 表达。与载体相比，A-192621 和 BQ-788 存在时，PASMC 对 DOX 诱导的凋亡的敏感性显著增加。然而，BQ-123 对这些参数没有影响。
ETB 受体的阻断增加了 PASMC 中的凋亡程度和对 DOX 诱导的凋亡的敏感性。ETB 受体阻断在 PASMC 中引起的凋亡可能是 ET 受体抑制剂为基础的 PAH 治疗中减少血管重构的机制之一。
