Development of molecular therapy correcting abnormal intracellular Ca^<2+> regulation in chronic heart failure

肌浆网对细胞内钙离子的异常调节与心力衰竭的收缩和松弛功能障碍有关。我们研究了通过Ryanodine受体(RyR)或通过SR钙ATPase(SERCA)/磷蛋白(PLN)复合体纠正慢性心力衰竭患者钙调节异常的分子靶向策略。在RyR中，我们发现致心律失常性右室发育不良患者的单个氨基酸突变可以触发氨基末端和中央多肽结构域之间的异常结构域相互作用，导致异常的SR钙泄漏和随后的胎儿心律失常。在衰竭的心脏中也观察到了同样的构象变化，提示了类似的心律失常发生机制。此外，这种钙泄漏也是由衰竭心脏中产生的活性氧物种(ROS)增加引发的。因此，降低ROS可能是一种新的STR…此外，我们还发现治疗恶性高热的经典药物丹曲林可以干扰RyR的这些异常构象变化，从而潜在地纠正衰竭心脏中受损的钙循环。另一方面，通过SERCA泵和网络SR中的磷蛋白摄取钙的功能也受到损害。这在一定程度上是由于Ser 16上的磷光蛋白磷酸化水平降低，可能是由于衰竭心脏中蛋白磷酸酶1(PP1)活性的增加所致。我们试图纠正这种PP1活性的异常增加。利用体内高效基因递送技术，我们将内源性PP1抑制物-2引入心肌病仓鼠心脏。结论：RyR或SERCA/PLN复合体中的分子靶向策略及其相关的PP1可能是治疗心力衰竭的良好靶点。较少

An abnormal regulation of intracellular Ca^<2+> by sarcoplasmic reticulum has been shown to be involved in the mechanism underlying contractile and relaxation dysfunction in heart failure. We investigated molecular targeting strategies of correcting the abnormal calcium regulation either via the ryanodine receptor (RyR) or via the SR calcium ATPase (SERCA) /phospholamban (PLN) complex in chronic heart failure. In RyR, we have found that a single amino acid mutation seen in the patient with arrhythmogenic right ventricular dysplasia can trigger abnormal domain interaction between amino-terminal and central peptide domain, leading to abnormal SR calcium leak and subsequent fetal arrhythmia. The same conformational change was observed in the failing heart, suggesting the similar arrhythmogenic mechanism. In addition, this kind of calcium leak is also triggered by the increased production of reactive oxygen species (ROS) in the failing heart. Therfore, reduction of ROS could be a novel str … More ategy to prevent fetal arrhythmia in heart failure Furthermore we also found that a classical medicine for malignant hyperthermia, dantrolene, can interfere with these abnormal conformational changes in RyR, thereby potentially correcting impaired calcium cycling in the failing heart.On the other hand, calcium uptake function via SERCA pump and phospholamban in the network SR is also impaired in the failing heart. This has in part been attributed to the decreased levels of pholpholamban phosphorylation at Ser 16, possibly caused by the increased protein phosphatase 1 (PP1) activity in the failing heart. We have attempted to correct this abnormal increase in PP1 activity. Using in vivo high efficiency gene delivery technique, we have introduced an endogenous constitutive PP1 inhibitor, inhibitor-2, into the cardiomyopathic hamster heart. Inhibitor-2 gene delivery not only rescued the cardiac finction but also ameliorated BNP expression, cardiac fibrosis and extended the consequent survival time.In summary, molecular targeting strategy in RyR or SERCA/PLN complex and associated PP1 could be a good therapeutic target for heart failure. Less