From the Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan (J.O., K.S., N.K., T.S., R.K., M.N., T.O., M.E.A.-M., M.A.H.S., N.Y.; S.S., S.M., H.S.).
Department of Thoracic Surgery, Fujita Health University School of Medicine, Toyoake, Japan (Y.H.).
Circ Res. 2019 Oct 25;125(10):884-906. doi: 10.1161/CIRCRESAHA.119.315398. Epub 2019 Sep 26.
Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling with aberrant pulmonary artery smooth muscle cells (PASMCs) proliferation, endothelial dysfunction, and extracellular matrix remodeling.
Right ventricular (RV) failure is an important prognostic factor in PAH. Thus, we need to elucidate a novel therapeutic target in both PAH and RV failure.
We performed microarray analysis in PASMCs from patients with PAH (PAH-PASMCs) and controls. We found a ADAMTS8 (disintegrin and metalloproteinase with thrombospondin motifs 8), a secreted protein specifically expressed in the lung and the heart, was upregulated in PAH-PASMCs and the lung in hypoxia-induced pulmonary hypertension (PH) in mice. To elucidate the role of ADAMTS8 in PH, we used vascular smooth muscle cell-specific ADAMTS8-knockout mice (ADAMTS). Hypoxia-induced PH was attenuated in ADAMTS mice compared with controls. ADAMTS8 overexpression increased PASMC proliferation with downregulation of AMPK (AMP-activated protein kinase). In contrast, deletion of ADAMTS8 reduced PASMC proliferation with AMPK upregulation. Moreover, deletion of ADAMTS8 reduced mitochondrial fragmentation under hypoxia in vivo and in vitro. Indeed, PASMCs harvested from ADAMTS mice demonstrated that phosphorylated DRP-1 (dynamin-related protein 1) at Ser637 was significantly upregulated with higher expression of profusion genes (Mfn1 and Mfn2) and improved mitochondrial function. Moreover, recombinant ADAMTS8 induced endothelial dysfunction and matrix metalloproteinase activation in an autocrine/paracrine manner. Next, to elucidate the role of ADAMTS8 in RV function, we developed a cardiomyocyte-specific ADAMTS8 knockout mice (ADAMTS8). ADAMTS8 mice showed ameliorated RV failure in response to chronic hypoxia. In addition, ADAMTS8 mice showed enhanced angiogenesis and reduced RV ischemia and fibrosis. Finally, high-throughput screening revealed that mebendazole, which is used for treatment of parasite infections, reduced ADAMTS8 expression and cell proliferation in PAH-PASMCs and ameliorated PH and RV failure in PH rodent models.
These results indicate that ADAMTS8 is a novel therapeutic target in PAH.
肺动脉高压（PAH）的特征是肺血管重构，伴有肺动脉平滑肌细胞（PASMC）异常增殖、内皮功能障碍和细胞外基质重构。
右心室（RV）衰竭是 PAH 的一个重要预后因素。因此，我们需要在 PAH 和 RV 衰竭中阐明一个新的治疗靶点。
我们对 PAH 患者（PAH-PASMCs）和对照组的 PASMC 进行了微阵列分析。我们发现，一种在肺和心脏中特异性表达的分泌蛋白 ADAMTS8（解整合素和金属蛋白酶与凝血酶样 8）在 PAH-PASMCs 和缺氧诱导的肺动脉高压（PH）小鼠的肺中上调。为了阐明 ADAMTS8 在 PH 中的作用，我们使用血管平滑肌细胞特异性 ADAMTS8 敲除小鼠（ADAMTS）。与对照组相比，缺氧诱导的 PH 在 ADAMTS 小鼠中减弱。ADAMTS8 过表达增加 PASMC 增殖，同时下调 AMPK（AMP 激活的蛋白激酶）。相反，ADAMTS8 的缺失减少了低氧条件下 PASMC 的增殖，同时上调了 AMPK。此外，ADAMTS8 的缺失减少了体内和体外低氧条件下的线粒体片段化。事实上，从 ADAMTS 小鼠中分离出的 PASMC 显示，磷酸化 DRP-1（dynamin-related protein 1）在 Ser637 处显著上调，融合基因（Mfn1 和 Mfn2）表达增加，线粒体功能改善。此外，重组 ADAMTS8 以自分泌/旁分泌方式诱导内皮功能障碍和基质金属蛋白酶激活。接下来，为了阐明 ADAMTS8 在 RV 功能中的作用，我们开发了一种心肌细胞特异性 ADAMTS8 敲除小鼠（ADAMTS8）。ADAMTS8 小鼠在慢性缺氧时表现出 RV 衰竭的改善。此外，ADAMTS8 小鼠表现出增强的血管生成和减少的 RV 缺血和纤维化。最后，高通量筛选显示，用于治疗寄生虫感染的甲苯咪唑可降低 PAH-PASMCs 中的 ADAMTS8 表达和细胞增殖，并改善 PH 啮齿动物模型中的 PH 和 RV 衰竭。
这些结果表明 ADAMTS8 是 PAH 的一个新的治疗靶点。
