权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Research in the inhibitory effect of sarcoplasmic reticulum Ca release channel stabilizer on the development of heart failure

肌浆网钙释放通道稳定剂抑制心力衰竭发展的研究

基本信息

批准号：
13670717
负责人：
YANO Masafumi
金额：
$ 2.56万
依托单位：
Yamaguchi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13670717/
关键词：
heart failure sarcoplasmic reticulum ryanodine receptor FK506 binding protein beta-blocker Ca放出能

项目摘要

In heart failure, abnormal function of sarcoplasmic reticulum (SR) is one of the major pathogenic mechanisms in heart failure. Here, we assessed the effects of 1,4-benzothiazepine derivative JTV519 (intracellular Ca2+ modulator) and propranolol on cardiac and SR functions. SR vesicles were isolated from dog LV muscles {normal (N), n=11; 4-weeks rapid RV pacing with or without JTV519 (JT:14.4 mg/Kg/day) or propranolol (PL:0.05mg/kg/day) [untreated: n=10, JT(+): n=10, PL(+): n=10, respectively]}. 1) In either JT(+) or PL(+), cardiac function was improved compared with untreated group. 2) Abnormal SR Ca2+ leak was found in untreated failing SR. A benzothiazepine Ca^<2+> antagonist diltiazem as well as JTV519 acutely inhibited this Ca^<2+> leak in failing SR (IC50= 0.3μM, 0.03μM, respectively), and neither nifedipine nor verapamil affected the Ca^<2+> leak. There was no abnormal SR Ca^<2+> leak either in JT(+) and PL(+). 3) Both JTV519 and propranolol prevented the decrease in the stoichiometry of RyR vs FKBP12.6 assessed by [^3H]ryanodine and [^3H]FK 506-bindng assays [1:3.6 in normal, 1:1.3 in untreated, 1:3.6 in JT(+), 1:2.4 in PL(+)]. 4) In untreated group, RyR was PKA- hyperphosphorylated, whereas it was reversed both in JT(+) and in PL(+). 5) The amount of RyR-bound FKBP12.6 was tremendously less in untreated group than normal RyR, whereas it was reversed both in JT(+) and PL(+). 6) RyR was labeled in a site-directed fashion with the fluorescent conformational probe methylcoumarin acetate (MCA). In both J(+) and P(+), the level of MCA fluorescence, which was higher in untreated group, was decreased back towards normal, suggesting the improvement of RyR conformational state by both treatments. Both JTV519 and proplanolol improved cardiac function and attenuated LV remodeling by ameliorating the defective interaction of FKBP12.6 with RyR through restoration of PKA-hyperphosphorylation of RyR and the following conformational change of RyR.

在心力衰竭中，肌浆网功能异常是心力衰竭的主要发病机制之一。在这里，我们评估了1，4-苯并硫氮类化合物JTV519(细胞内钙调节剂)和心得安对心脏和SR功能的影响。从犬左室肌分离出SR囊泡[正常(N)，n=11；快速右室起搏加或不加JTV519(JT：14.4 mg/kg/d)或普奈洛尔(PL：0.05 mg/kg/d)][未处理：n=10，JT(+)：n=10，PL(+)：n=10]。1)无论是JT(+)组还是PL(+)组，心功能均较未治疗组明显改善。2)未治疗失败的SR存在异常的肌浆网钙离子泄漏。苯并硫氮类钙离子拮抗剂地尔硫卓和JTV519可显著抑制SR失败时的钙泄漏(IC_(50)分别为0.3μM和0.03μM)，硝苯地平和维拉帕米均不影响钙泄漏。JT(+)和PL(+)均未发现异常的SR钙渗漏。3)JTV519和普奈洛尔均能阻止RyR与FKBP12.6结合的RyR与FKBP12.6的化学计量比下降[正常1：3.6，未治疗1：1.3，JT(+)1：3.6，PL(+)]。4)在未治疗组，RyR蛋白过度磷酸化，而在JT(+)和PL(+)中均发生逆转。5)未治疗组RyR结合FKBP12.6的数量明显少于正常RyR，而JT(+)和PL(+)的RyR结合FKBP12.6的数量则相反。6)用荧光构象探针甲基香豆素醋酸酯(MCA)定点标记RyR。在J(+)和P(+)中，未治疗组的MCA荧光水平均下降至正常水平，提示两种治疗方法均能改善RyR的构象状态。JTV519和心得安均通过恢复RyR的PKA过度磷酸化及随后的RyR构象变化，改善FKBP12.6与RyR的异常相互作用，从而改善心功能，减轻LV重构。