BACKGROUND:Pulmonary arterial hypertension (PAH) is high blood pressure in the lungs that originates from structural changes in small resistance arteries. A defining feature of PAH is the inappropriate remodeling of pulmonary arteries (PA) leading to right ventricle failure and death. Although treatment of PAH has improved, the long-term prognosis for patients remains poor, and more effective targets are needed.METHODS:Gene expression was analyzed by microarray, RNA sequencing, quantitative polymerase chain reaction, Western blotting, and immunostaining of lung and isolated PA in multiple mouse and rat models of pulmonary hypertension (PH) and human PAH. PH was assessed by digital ultrasound, hemodynamic measurements, and morphometry.RESULTS:Microarray analysis of the transcriptome of hypertensive rat PA identified a novel candidate, PBK (PDZ-binding kinase), that was upregulated in multiple models and species including humans. PBK is a serine/threonine kinase with important roles in cell proliferation that is minimally expressed in normal tissues but significantly increased in highly proliferative tissues. PBK was robustly upregulated in the medial layer of PA, where it overlaps with markers of smooth muscle cells. Gain-of-function approaches show that active forms of PBK increase PA smooth muscle cell proliferation, whereas silencing PBK, dominant negative PBK, and pharmacological inhibitors of PBK all reduce proliferation. Pharmacological inhibitors of PBK were effective in PH reversal strategies in both mouse and rat models, providing translational significance. In a complementary genetic approach, PBK was knocked out in rats using CRISPR/Cas9 editing, and loss of PBK prevented the development of PH. We found that PBK bound to PRC1 (protein regulator of cytokinesis 1) in PA smooth muscle cells and that multiple genes involved in cytokinesis were upregulated in experimental models of PH and human PAH. Active PBK increased PRC1 phosphorylation and supported cytokinesis in PA smooth muscle cells, whereas silencing or dominant negative PBK reduced cytokinesis and the number of cells in the G2/M phase of the cell cycle.CONCLUSIONS:PBK is a newly described target for PAH that is upregulated in proliferating PA smooth muscle cells, where it contributes to proliferation through changes in cytokinesis and cell cycle dynamics to promote medial thickening, fibrosis, increased PA resistance, elevated right ventricular systolic pressure, right ventricular remodeling, and PH.

中文翻译：

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PDZ 结合激酶，肺动脉高压血管重塑的新型调节剂

背景：肺动脉高压（PAH）是肺部高血压，源于小阻力动脉的结构变化。 PAH 的一个显着特征是肺动脉 (PA) 的不适当重塑，导致右心室衰竭和死亡。尽管PAH的治疗有所改善，但患者的长期预后仍然较差，需要更有效的靶点。方法：通过微阵列、RNA测序、定量聚合酶链反应、Western blotting和免疫染色分析肺和分离物的基因表达。 PA 在多种小鼠和大鼠肺动脉高压 (PH) 和人类 PAH 模型中的应用。通过数字超声、血流动力学测量和形态测量来评估 PH。 结果：对高血压大鼠 PA 转录组的微阵列分析发现了一种新的候选物 PBK（PDZ 结合激酶），它在包括人类在内的多个模型和物种中表达上调。 PBK 是一种丝氨酸/苏氨酸激酶，在细胞增殖中发挥重要作用，在正常组织中表达量最低，但在高度增殖组织中表达显着增加。 PBK 在 PA 的内侧层中显着上调，它与平滑肌细胞的标记物重叠。功能获得方法表明，活性形式的 PBK 会增加 PA 平滑肌细胞的增殖，而沉默 PBK、显性失活 PBK 和 PBK 的药物抑制剂都会减少增殖。 PBK 的药理学抑制剂在小鼠和大鼠模型中的 PH 逆转策略中均有效，具有转化意义。在一种互补的遗传方法中，使用 CRISPR/Cas9 编辑在大鼠中敲除 PBK，并且 PBK 的缺失阻止了 PH 的发展。我们发现，PBK 与 PA 平滑肌细胞中的 PRC1（胞质分裂蛋白调节因子 1）结合，并且在 PH 和人类 PAH 实验模型中，参与胞质分裂的多个基因上调。活性 PBK 增加 PA 平滑肌细胞中的 PRC1 磷酸化并支持胞质分裂，而沉默或显性失活 PBK 则减少胞质分裂和细胞周期 G2/M 期的细胞数量。结论：PBK 是新近描述的 PAH 靶点，即在增殖的 PA 平滑肌细胞中上调，通过胞质分裂和细胞周期动力学的变化促进增殖，从而促进内侧增厚、纤维化、PA 阻力增加、右心室收缩压升高、右心室重塑和 PH。