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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（SR）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-苯并硫氮杂卓衍生物JTV 519（细胞内Ca 2+调节剂）和普萘洛尔对心脏和SR功能的影响。从狗LV肌肉中分离SR囊泡{正常（N），n=11; 4周快速RV起搏，有或没有JTV 519（JT：14.4 mg/Kg/天）或普萘洛尔（PL：0.05 mg/kg/天）[分别为未处理的：n= 10，JT（+）：n=10，PL（+）：n=10]}。1)JT（+）或PL（+）组心功能较未治疗组均有改善。2)在未治疗的衰竭SR中发现了异常的SR Ca ^2+渗漏，苯并硫氮卓类Ca^2+拮抗剂地尔硫卓和JTV 519可急性抑制衰竭SR中的这种Ca^2+渗漏（IC 50分别为0.3μM和0.03μM），硝苯地平和维拉帕米均不影响Ca^2+渗漏。JT（+）和PL（+）均未见异常SR Ca^2+渗漏。3)JTV 519和普萘洛尔均能防止RyR与FKBP 12.6的化学计量比下降，这是通过[^3H]ryanodine和[^3H]FK 506结合试验评估的[正常组为1：3.6，未治疗组为1：1.3，JT（+）组为1：3.6，PL（+）组为1：2.4]。4)未治疗组RyR蛋白PKA-过度磷酸化，而JT（+）组和PL（+）组RyR蛋白PKA-过度磷酸化。5)未处理组RyR结合FKBP 12.6的量显著低于正常RyR，而JT（+）和PL（+）组则相反。6)RyR标记的荧光构象探针甲基香豆素乙酸酯（MCA）的定点方式。在J（+）和P（+）中，未处理组中较高的MCA荧光水平降低回到正常，表明两种处理均改善了RyR构象状态。JTV 519和普拉洛尔通过恢复RyR的PKA-过度磷酸化和随后的RyR构象变化来改善FKBP 12.6与RyR的缺陷性相互作用，从而改善心脏功能并减弱LV重构。