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

肌浆网对细胞内Ca^<2+>的异常调节已被证明参与心力衰竭收缩和舒张功能障碍的机制。我们研究了慢性心力衰竭患者通过红嘌呤受体（RyR）或SR钙atp酶(SERCA) /磷蛋白（PLN）复合物纠正异常钙调节的分子靶向策略。在RyR中，我们发现在致心律失常的右心室发育不良患者中发现的单个氨基酸突变可触发氨基末端和中心肽区域之间的异常结构域相互作用，导致SR钙异常渗漏和随后的胎儿心律失常。在衰竭的心脏中也观察到相同的构象变化，提示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活性氧（ROS）的产生增加引起的。因此，减少ROS可能是一种预防心力衰竭胎儿心律失常的新策略。此外，我们还发现一种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，衰竭心脏通过SERCA泵和SR网络中的磷蛋白的钙摄取功能也受到损害。这部分归因于在丝氨酸16磷酸化水平的降低，可能是由于衰竭心脏中蛋白磷酸酶1 （PP1）活性的增加引起的。我们试图纠正这种PP1活性的异常增加。利用体内高效基因传递技术，我们将内源性组成型PP1抑制剂inhibitor-2引入心肌病仓鼠心脏。抑制剂-2基因的传递不仅挽救了心功能，而且改善了BNP的表达和心脏纤维化，延长了生存时间。综上所述，RyR或SERCA/PLN复合物及相关PP1的分子靶向策略可能是心力衰竭的良好治疗靶点。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