Computationally designed phospholamban-SERCA for rectifying diabetic cardiomyopa

描述(申请人提供)：糖尿病是一种流行病，困扰着2500万美国人和近3.5亿世界各地的人。糖尿病心肌病(DCM)是一种心脏病变，在许多糖尿病患者中出现，导致心力衰竭的不成比例风险。心力衰竭的部分原因是心肌细胞内钙离子调节功能失调。钙离子在心肌细胞的兴奋和机械活动以及致病改变中起着关键作用，其信号通路增加了发生危险心律失常的倾向。肌浆网钙含量降低是DCM的主要原因，肌浆网钙ATPase(SERCA)对钙的摄取不足是造成DCM的部分原因。SERCA、其内源性抑制物、磷蛋白(PLB)和蛋白激酶在调节SR含量和钙信号转导方面的复杂相互作用使我们对DCM的理解复杂化。为此，心肌细胞中特定物种和DCM的钙信号数学模型能够整合不同的实验探针，从分子和细胞水平研究PLB/SERCA的病理性功能。在目标1中，将利用分子动力学模拟来探索PLB与SERCA结合的分子基础，并确定提高ATPase活性的靶点。在目标2中，将使用钙信号和磷酸化的细胞模型来检验增强的SERCA摄取在恢复正常心功能方面的影响，包括CaMKII和β-肾上腺素能刺激的影响。在短期内，这些目标的成功完成将使人们能够通过调节PLB的相互作用来精确控制SERCA，从而潜在地产生治疗糖尿病心肌病的小分子靶点。从长远来看，分子和细胞对功能失调的钙调节的洞察提供了对糖尿病心肌病和心力衰竭的机械性洞察。

DESCRIPTION (provided by applicant): Diabetes is an epidemic afflicting 25 million Americans and nearly 350 million persons world-wide. Diabetic cardiomyopathy (DCM) is a cardiac pathology presented in many of those afflicted by diabetes, which contributes to a disproportionate risk of heart failure. Heart failure in part stems from the dysfunctional regulatin of calcium (Ca2+) in cardiomyocytes. Ca2+ plays a critical role in the excitation and mechanical activity of cardiac cells and pathogenic alterations its signaling pathways increase the propensity for dangerous arrhythmias. Reduced sarcoplasmic reticulum (SR) Ca2+ content is a major contributor to DCM, and deficient Ca2+ uptake by the sarcoplasmic reticulum Ca2+ ATPase (SERCA) is partially at fault. The complex interplay between SERCA, its endogenous inhibitor, phospholamban (PLB), and protein kinases in regulating SR content and Ca2+ signaling complicates our understanding of DCM. To this end, species- and DCM-specific mathematical models of Ca2+ signaling in cardiomyocytes enable the integration of diverse experimental probes of molecular-and cellular-level aspects of pathological PLB/SERCA function. In Aim 1, the molecular basis of PLB binding to SERCA and identify targets for increasing ATPase activity will be explored using molecular dynamics simulations. In Aim 2, the impact of enhanced SERCA uptake in restoring normal cardiac function, including the effects of CaMKII and beta-adrenergic stimulation, using a cellular model of Ca2+ signaling and phosphorylation will be examined. In the short term, successful completion of these aims will yield insight into precise control of SERCA by tuning the PLB interaction, thereby potentially yielding small-molecule targets to treat diabetic cardiomyopathy. In the long term, molecular and cellular insight into dysfunctional calcium regulation provide a mechanistic insight into diabetic cardiomyopathy and heart failure, in general.