Role of Rho-kinase signaling in heart and its involvement of cardiac diseases

Rho激酶信号在心脏中的作用及其与心脏病的关系

• 批准号: 14370223
• 负责人: ITO Masaaki
• 金额: $ 9.02万
• 依托单位: Mie University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14370223/
• 关键词: Rho-kinase; RhoA; Myosin phosphatase; MYPT2; MYPT1; Myosin light chain phosphorylation; Ca^<2+> sensitization; Cardiomyocyte; Rho-kinase; RhoA; Myosin phosphatase; MYPT2; MYPT1; Myosin light chain phosphorylation; Ca^<2+> sensitization; Cardiomyocyte

The roles of RhoA/Rho-kinase/myosin phosphatase (MP) signaling in heart and its involvement in cardiac diseases had been investigated.Myosin phosphatase target subunit 2 (MYPT2) could interact with a catalytic subunit of type 1 phosphatase δ isoform (PP1cδ) and HS-M_<21> to form a cardiac myosin phosphatase holoenzyne. MYPT2 was identified to be a target of the active form of RhoA. Rho-kinase phosphorylated MYPT2 and its thiophosphorylation could induce the inhibition of MP activity. The cultured rat neonatal cardiomyocytes overexpressing MYPT2-PP1cδ showed the lower levels of myosin light chain 2 (MLC2) phosphorylation and were resistant to the sarcomere organization induced by angitensin II, indicating that MYPT2-PP1cδ could act as MP and was involved in sarcomere organization.The heart of the cardiac-specific MYPT2-PP1cδ transgenic mice (Tg) showed the dilated cardiomyopathy-like phenotypes, including the enlargement of LV dimension, thinning of LV wall and the reduced fractional sh … More ortening. The papillary muscle of Tg heart showed the reduced Ca^<2+> sensitivity of contraction and the phosphorylation levels of MLC2 were signfficantly lower as compared with wild type. These results suggested that MP play a role to regulate MLC2 phosphorylation and MLC2 phosphorylation level is important to maintain normal cardiac functions in vivo.To analyze the functions of Rho-kinase in heart, the conditional transgenic mice overexpressing the dominant negative or the constitutively active fragment of Rho-kinase were generated. However, the double transgenic mice of each Tg and heart-specific Cre mice failed to induce an enough amount of each fragment and no phenotypes were observed. Therefore, the conditional transgenic mice overexpressing the active fragment of leukemia-associated Rho guanine nucleotide exchange factors (LARG-Tg) were generated to investigate the Rho/Rho-kinase signaling in heart. We will continue to make the double transgenic mice of LARG-Tg and Cre mice to investigate its phenotypes to understand the role of Rho/Rho-kinase signaling in heart. Less

已经研究了RhoA/Rho-激酶/肌球蛋白磷酸酶（MP）信号在心脏及其参与心脏疾病的作用。肌醇磷酸酶靶标亚基2（MYPT2）可以与1型磷酸酶δ同源型（PP1CΔ）和HS-M____________ <21> CARPERIN的催化亚基相互作用。 MyPT2被确定为RhoA.RHO-激酶磷酸化的MyPT2的活性形式的靶标，其硫磷酸化可以诱导MP活性的抑制。过表达MyPT2-PP1Cδ的培养的大鼠新生儿心肌细胞表明，肌球蛋白光链2（MLC2）磷酸化的水平较低，并且对由Angitensin II诱导的肉壳组织具有抵抗力，表明MYPT2-PPP1CΔ可以作为MP和sarmomeciciic Miceciciic of carmote of carmote of carmote of carmote of carmote of carmote oft of carmote of carmct2222 （TG）显示了膨胀的心肌病样表型，包括LV尺寸的扩展，LV壁的变薄以及减少的分数SH…更荒谬。与野生型相比，TG心脏的乳头肌显示出收缩的Ca^<2+>敏感性降低，MLC2的磷酸化水平显着降低。这些结果表明，MP在调节MLC2磷酸化和MLC2磷酸化水平方面起作用，对于维持体内的正常心脏功能至关重要。为了分析Rho-kinase在心脏中的功能，有条件的转基因小鼠过表达了主要表达的阴性或rho-kinase的强度活跃片段。但是，每只TG和心脏特异性CRE小鼠的双转基因小鼠无法诱导每个片段足够多，并且未观察到表型。因此，产生了与白血病相关的Rho鸟嘌呤核交换因子（LARG-TG）过表达活性片段的条件转基因小鼠，以研究心脏中的Rho/Rho-激酶信号传导。我们将继续制作Larg-TG和Cre小鼠的双重转基因小鼠，以研究其表型，以了解Rho/Rho-激酶信号在心脏中的作用。较少的