Crucial Role of ROCK2-Mediated Phosphorylation and Upregulation of FHOD3 in the Pathogenesis of Angiotensin II-Induced Cardiac Hypertrophy
Crucial Role of ROCK2-Mediated Phosphorylation and Upregulation of FHOD3 in the Pathogenesis of Angiotensin II-Induced Cardiac Hypertrophy
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ROCK2 介导的 FHOD3 磷酸化和上调在血管紧张素 II 诱导的心肌肥厚发病机制中的关键作用
DOI：
10.1161/hypertensionaha.116.08662
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发表时间：
2017
期刊：
影响因子：
8.3
通讯作者：
Wang YP
中科院分区：
文献类型：
--
作者：
Zhou Q;Wei SS;Wang H;Wang Q;Li W;Li G;Hou JW;Chen XM;Chen J;Xu WP;Li YG;Wang YP
心肌肥大的特征是肌原纤维生成增加。血管紧张素II（Ang-II）是压力超负荷诱导的心肌肥厚的重要介质，部分通过RhoA/ROCK（small GTdR/Rho-associated coiled-coil containing protein kinase）途径。FHOD 3（含3个同源结构域的FHOD 3）是透明相关形成蛋白中的心脏限制性成员，在调节心肌细胞肌原纤维发生中至关重要。FHOD 3通过其C-和N-末端结构域之间的分子内相互作用通过自身抑制保持无活性。ROCK 1对FHOD 3 C末端（CT）内3个高度保守残基（1406 S、1412 S和1416 T）的磷酸化足以使其活化。然而，目前尚不清楚ROCK介导的FHOD 3激活是否在Ang-II诱导的心肌肥大的发病机制中起作用。在这项研究中，我们检测到增加FHOD 3的表达和磷酸化的心肌细胞从Ang-II诱导的大鼠心肌肥大模型。缬沙坦减弱了这种增加。在培养的新生大鼠心肌细胞中，过表达拟磷突变体FHOD 3-DDD，而不是野生型FHOD 3，导致肌原纤维形成和心肌细胞肥大。磷酸盐抗性突变体FHOD 3-AAA的表达完全消除了肌原纤维生成，并减弱了Ang-II诱导的心肌细胞肥大。用ROCK抑制剂Y27632预处理新生大鼠心肌细胞可降低Ang-II诱导的FHOD 3激活和上调，表明ROCK活性参与其中。在新生大鼠心肌细胞中，ROCK 2沉默，而不是ROCK 1沉默，显著减轻Ang-II诱导的心肌细胞肥大。ROCK 2在体外可直接在1412 S和1416 T处磷酸化FHOD 3，并且比ROCK 1更有效。两种激酶均未能磷酸化1406 S。FHOD 3与组成型活性ROCK 2的共表达比与组成型活性ROCK 1的共表达诱导更多的应力纤维形成。总之，我们的研究结果表明ROCK 2调节FHOD 3的表达和激活在Ang-II诱导的肌原纤维形成中的重要性，从而为Ang-II诱导的心肌肥大的发病机制提供了新的机制。
Cardiac hypertrophy is characterized by increased myofibrillogenesis. Angiotensin II (Ang-II) is an essential mediator of the pressure overload–induced cardiac hypertrophy in part through RhoA/ROCK (small GTPase/Rho-associated coiled-coil containing protein kinase) pathway. FHOD3 (formin homology 2 domain containing 3), a cardiac-restricted member of diaphanous-related formins, is crucial in regulating myofibrillogenesis in cardiomyocytes. FHOD3 maintains inactive through autoinhibition by an intramolecular interaction between its C- and N-terminal domains. Phosphorylation of the 3 highly conserved residues (1406S, 1412S, and 1416T) within the C terminus (CT) of FHOD3 by ROCK1 is sufficient for its activation. However, it is unclear whether ROCK-mediated FHOD3 activation plays a role in the pathogenesis of Ang-II–induced cardiac hypertrophy. In this study, we detected increases in FHOD3 expression and phosphorylation in cardiomyocytes from Ang-II–induced rat cardiac hypertrophy models. Valsartan attenuated such increases. In cultured neonate rat cardiomyocytes, overexpression of phosphor-mimetic mutant FHOD3-DDD, but not wild-type FHOD3, resulted in myofibrillogenesis and cardiomyocyte hypertrophy. Expression of a phosphor-resistant mutant FHOD3-AAA completely abolished myofibrillogenesis and attenuated Ang-II–induced cardiomyocyte hypertrophy. Pretreatment of neonate rat cardiomyocytes with ROCK inhibitor Y27632 reduced Ang-II–induced FHOD3 activation and upregulation, suggesting the involvement of ROCK activities. Silencing of ROCK2, but not ROCK1, in neonate rat cardiomyocytes, significantly lessened Ang-II–induced cardiomyocyte hypertrophy. ROCK2 can directly phosphorylate FHOD3 at both 1412S and 1416T in vitro and is more potent than ROCK1. Both kinases failed to phosphorylate 1406S. Coexpression of FHOD3 with constitutively active ROCK2 induced more stress fiber formation than that with constitutively active ROCK1. Collectively, our results demonstrated the importance of ROCK2 regulated FHOD3 expression and activation in Ang-II–induced myofibrillogenesis, thus provided a novel mechanism for the pathogenesis of Ang-II–induced cardiac hypertrophy.