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

基本信息

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

项目摘要

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

研究人员研究了 RhoA/Rho 激酶/肌球蛋白磷酸酶 (MP) 信号在心脏中的作用及其与心脏病的关系。肌球蛋白磷酸酶靶亚基 2 (MYPT2) 可以与 1 型磷酸酶 δ 亚型 (PP1cδ) 的催化亚基相互作用和HS-M_ 21 形成心肌肌球蛋白磷酸酶全酶。 MYPT2 被确定为 RhoA 活性形式的靶标，其硫代磷酸化可诱导 MP 活性的抑制。过表达 MYPT2-PP1cδ 的培养的大鼠新生心肌细胞显示肌球蛋白轻链 2 (MLC2) 水平较低。 ) 磷酸化并且对血管紧张素 II 诱导的肌节组织具有抵抗力，表明MYPT2-PP1cδ可以作为MP并参与肌节组织。心脏特异性MYPT2-PP1cδ转基因小鼠(Tg)的心脏表现出扩张型心肌病样表型，包括左心室尺寸增大、左心室壁变薄和左心室壁变薄。 Tg心脏的乳头肌收缩敏感性降低，MLC2磷酸化水平降低。这些结果表明MP对MLC2磷酸化具有调节作用，并且MLC2磷酸化水平对于维持体内正常心脏功能具有重要意义。为分析Rho激酶在心脏中的功能，条件性转基因小鼠过表达。产生了Rho激酶的显性失活或组成型活性片段，然而，每个Tg和心脏特异性Cre小鼠的双转基因小鼠未能诱导足够量的每个片段和。没有观察到表型，因此，产生了过表达白血病相关Rho鸟嘌呤核苷酸交换因子（LARG-Tg）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。 LARG-Tg 和 Cre 小鼠的转基因小鼠研究其表型，以了解 Rho/Rho 激酶信号在心脏 Less 中的作用。