Natural Agonists of Ryanodine Receptors: Structure-function Relationship and Antiarrhythmic Properties

兰尼定受体的天然激动剂：结构-功能关系和抗心律失常特性

• 批准号: 9650244
• 负责人: Hector H Valdivia
• 金额: $ 46.18万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2021-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9650244
• 关键词: Active Sites; Acute; Adrenergic alpha-Antagonists; Affinity; Agonist; Amino Acids; Animal Model; Animals; Arrhythmia; Binding; Binding Sites; Calcium; Calcium Channel; Cardiac Myocytes; Cardiomyopathies; Catecholaminergic Polymorphic Ventricular Tachycardia; Cell physiology; Cells; Cellular Membrane; Central Core Myopathy; Characteristics; Charge; Communities; Complex; Disadvantaged; Dissociation; Dose; Enzyme Activation; Functional disorder; Generations; Goals; Heart; Heart failure; Hyperactive behavior; Ions; Kinetics; Ligands; Location; Malignant hyperpyrexia due to anesthesia; Maps; Metabolic; Molecular; Muscle Cells; Myocardium; Names; Penetration; Peptides; Pharmacology; Plant alkaloid; Play; Property; Proteins; Receptor Activation; Recombinants; Regulation; Research; Role; RyR2; Ryanodine; Ryanodine Receptor Calcium Release Channel; Ryanodine Receptors; Sarcoplasmic Reticulum; Scorpion Venoms; Scorpions; Signal Transduction; Skeletal Muscle; Specificity; Speed; Structure-Activity Relationship; Syndrome; Testing; Transcriptional Regulation; Venoms; Ventricular; dipole moment; experimental study; functional group; imperatoxin A; multidisciplinary; mutant; novel; prevent; programs; receptor; receptor function; receptor structure function; success; thermostability

ABSTRACT Ryanodine receptors (RyR) are sarcoplasmic reticulum Ca2+ release channels that play a critical role in Ca2+ signaling of excitable and non-excitable cells. RyRs owe their name to the fact that they were characterized in great part thanks to ryanodine, a plant alkaloid that binds to RyRs with high affinity and specificity. Ryanodine has been an invaluable ligand of RyRs, but its functional effects are complex and hamper its use in cellular studies. In search of novel ligands that could overcome some of the functional and structural disadvantages of ryanodine, we found in the venom of selected scorpions a set of peptide ligands, termed calcins, displaying high affinity and exquisite selectivity against RyRs. The defining characteristic of calcins is their capacity to stabilize RyR openings in a long-lasting subconducting state. This effect is nearly analogous to that of ryanodine, but unlike ryanodine, calcins bind rapidly to RyRs (fast association rate), freely dissociate from their binding site (reversible effect), display a dose- and sequence-variable effect, and are amenable for derivatization without undergoing major loss in receptor affinity. Calcins also modulate intracellular Ca2+ in intact cardiomyocytes with remarkable speed and with several degrees of potency, thus entering the field as the first cell-penetrating peptides (CPP) RyR-specific Ca2+ mobilizer of high dynamic range. This research program will characterize first and then exploit this novel group of peptide ligands to unravel fundamental mechanisms of RyR function at the molecular, cellular and whole heart level. Our multidisciplinary program, with well-defined deliverables and milestones, may be enveloped in two specific aims. In the first aim, we will first identify and modify the structural domains of calcins involved in RyR recognition and cell penetration to generate a group of functionally diverse CPPs capable of modulating RyR function with wide dynamic range and of delivering cargo to the interior of cardiomyocytes. In the second aim, we will use native and mutant calcins on intact cardiomyocytes, Langendorff-perfused working hearts and intact animals to create acute or sustained periods of RyR hyperactivity and reveal mechanisms of RyR gating, SR Ca2+ load and Ca2+-triggered arrhythmias. These studies use animal models of catecholaminergic polymorphic ventricular tachycardia to develop a novel paradigm for the treatment of calcium-dependent arrhythmias; results may be applied to other cardiomyopathies where controlled unloading of SR Ca2+ may be desirable.

抽象的 ryanodine受体（RYR）是肌质网Ca2+释放通道，在 CA2+可激发和非驱动细胞的信号传导。里尔斯的名字归功于他们的特征 大部分要归功于瑞安丁（Ryanodine），这是一种与高亲和力和特异性的Ryrs结合的植物生物碱。 ryanodine拥有 是RYR的宝贵配体，但其功能效应很复杂，并阻碍了其在细胞研究中的使用。在 搜索可以克服Ryanodine的某些功能和结构缺点的新型配体，我们 在选定蝎子的毒液中发现了一组肽配体，称为Calcins，显示高亲和力和 针对Ryrs的精美选择性。 Calcins的定义特征是它们稳定Ryr Openings的能力 持久的子导状态。这种作用几乎与瑞氨烷的作用相似，但与ryanodine不同，Calcins 与RYRS快速结合（快速关联率），从其结合位点自由解离（可逆效果），显示出剂量 - 和序列可变性的效应，并且可以衍生化，而无需受到受体亲和力的重大损失。 钙蛋白还以显着的速度和几个程度的完整心肌细胞调节细胞内Ca2+ 效力，因此进入田地，作为第一个细胞穿透肽（CPP）Ryr特异性CA2+高动员 动态范围。该研究计划将首先表征 分子，细胞和整个心脏水平的RYR功能的基本机制。我们的多学科 具有明确定义的可交付成果和里程碑的计划可能包含在两个具体目标中。在第一个目标中，我们 将首先识别并修改参与RYR识别和细胞渗透到RYR识别和细胞的结构结构域 生成一组功能多样的CPP，能够调节RYR功能，并具有广泛的动态范围和 将货物运送到心肌细胞内部。在第二个目标中，我们将在完整的 心肌细胞，Langendorff丰满的工作心脏和完整的动物，以创建RYR的急性或持续时间 多动症和RYR门控，SR CA2+负载和Ca2+触发心律不齐的机制。这些研究使用 儿茶酚胺能多态性心室心动过速的动物模型，以开发一种新型范式进行治疗 钙依赖性心律不齐；结果可以应用于其他心肌病，在该心肌病中， SR CA2+可能是可取的。