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，肌质网（SR）的异常功能是心力衰竭中主要的致病机制之一。在这里，我们评估了1,4-苯甲噻嗪衍生物JTV519（细胞内CA2+调节剂）和普萘洛尔对心脏和SR功能的影响。从狗LV肌肉{正常（n），n = 11中分离出SR蔬菜；有或没有JTV519（JT：14.4 mg/kg/day）或普萘洛尔（PL：0.05mg/kg/day）的4周快速起搏[未处理：n = 10，jt（+）：n = 10，pl（+）：n = 10，pl（+）：n = 10，分别为n = 10]}。 1）在JT（+）或PL（+）中，与未经处理的组相比，心脏功能得到改善。 2）在未处理的失败SR中发现了异常的SR Ca2+泄漏。苯锡锡氮杂Ca^<2+>拮抗剂diltiazem以及JTV519急性抑制了失败的SR泄漏（分别为IC50 =0.3μm，0.03μm），既没有影响Ca^<2+>漏洞。在JT（+）和PL（+）中，没有异常的SR Ca^<2+>泄漏。 3）JTV519和普罗诺酚都阻止了RYR vs fkbp12.6的化学计量降低，由[^3H] ryanodine和[^3H] fk 506 fk 506-bindng测定法[1：3.6在正常中，1：3.6 In intreated，1：3.6 In jt in Jt（+）in jt（+），1：2.4，1：2.4 in（+）。 4）在未处理的组中，RYR被PKA-磷酸化，而在JT（+）和PL（+）中都被逆转。 5）在未经处理的组中，RYR结合的FKBP12.6的量比正常的RYR少得多，而在JT（+）和PL（+）中都相反。 6）RYR以荧光协商探针乙酸甲酯（MCA）为定向的方式标记。在J（+）和P（+）中，未经处理组的MCA荧光水平较高，恢复了正常状态，这表明两种治疗方法都改善了RYR构象状态。 JTV519和丙醇都通过改善FKBP12.6与RYR的有缺陷相互作用，通过恢复RYR的PKA倍磷酸化和以下RYR的构象变化，从而改善了心脏功能并减弱LV重塑。