First-in-class peptide therapeutics for mitochondrial disorders: molecular mechanism of action and optimization of design

项目总结 线粒体是在能量代谢和许多其他细胞中起主导作用的细胞器。 流程。线粒体功能障碍与原发性遗传性疾病和衰老相关的衰退有关 在健康方面，包括癌症、糖尿病和神经变性等慢性疾病。目前没有 治疗线粒体疾病的药物。然而，司徒席勒(Szeto-Schiller，SS)多肽出现在最多的 促进线粒体健康的前景看好的疗法。如临床前和临床试验所示，以及AS 以先导化合物SS-31(伊拉米普利)为例，SS多肽显示出特别广泛的治疗作用 治疗线粒体功能障碍的疗效。使用多学科方法，我们的研究团队已经 首次深入分析了SS多肽的分子作用机制(MOA)。我们的工作 支持SS多肽与富含心磷脂的线粒体膜相互作用的独特机制 调节一般的物理膜特性，从而支持其广泛的治疗潜力。这个 拟议项目的目标是双重的。第一个目标是彻底了解SS多肽的MOA。 为此，我们将利用我们坚实的机械洞察力基础来测试、改进和扩展我们的 使用计算、简化论、线粒体和细胞系统的工作模型。第二个目标是 确定对其作用机制最关键的SS多肽的物理化学性质。为此， 我们将评估一系列合理设计的SS多肽结构与四肽的变化 阳离子/芳香族基序，使用我们建立的功能分析。凭借我们高度跨学科的研究 团队，我们将把这些目标作为三个不同的目标。首先，我们将讨论SS肽是如何相互作用的 利用计算和生物物理的组合来调节它们的物理性质 仿生模型膜系统的研究进展。这将提供有关均衡的关键信息 多肽结合模型、多肽构象动力学的高分辨结构信息和 与脂质基团的相互作用，以及多肽如何调制膜静电，脂质结构动力学， 和双层多态改变。其次，我们将评估SS肽对结构和功能的影响 酵母和哺乳动物模型膜的功能。这将建立肽相互作用的位置在 形态复杂的线粒体，多肽如何影响膜的稳定性和组装 复合体、线粒体内脂质的分布和脂类周转动力学。最后，使用线粒体 和细胞模型，我们将分析SS肽在病理条件下恢复功能的机制 与II型糖尿病有关的条件，包括氧化应激、高钙负荷和淀粉样蛋白 和阿尔茨海默氏症。通过这种多层次的方法，我们的结果将产生前所未有的洞察 这类疗法的机制与衰老相关的疾病特别相关。此外，我们的 肽筛选将为SS多肽变体的设计提供信息，使其具有更好的疗效和/或生物利用度。

PROJECT SUMMARY Mitochondria are organelles that play a dominant role in energy metabolism and many other cellular processes. Mitochondrial dysfunction is associated with primary heritable diseases and aging-related declines in health, including chronic pathologies like cancer, diabetes and neurodegeneration. There are currently no cures for mitochondrial diseases. However, Szeto-Schiller (SS) peptides have emerged among the most promising therapeutics for promoting mitochondrial health. As shown by preclinical and clinical trials, and as exemplified by the lead compound SS-31 (Elamipretide), SS peptides show exceptionally broad therapeutic efficacy in treating mitochondrial dysfunction. Using a multidisciplinary approach, our research team has conducted the first in-depth analysis of the molecular mechanism of action (MoA) of SS peptides. Our work supports a unique mechanism in which SS peptides interact with cardiolipin-rich mitochondrial membranes and modulate general physical membrane properties, thereby underpinning their broad therapeutic potential. The objective of the proposed project is twofold. The first goal is to thoroughly understand the MoA of SS peptides. To this end, we will leverage our solid foundation of mechanistic insights to test, refine, and expand our working models using computational, reductionist, mitochondrial, and cellular systems. The second goal is to identify the physicochemical properties of SS peptides that are most critical to their mechanism. To this end, we will evaluate a series of rationally designed SS peptide constructs with variations in the tetrapeptide cationic/aromatic motif, using our established functional assays. With our highly interdisciplinary research team, we will approach these goals as three separate aims. First, we will address how SS peptides interact with lipid bilayers and modulate their physical properties using a combination of computational and biophysical approaches with biomimetic model membrane systems. This will render critical information on equilibrium peptide binding models, high resolution structural information on peptide conformational dynamics and interaction with lipid groups, and how peptides modulate membrane electrostatics, lipid structural dynamics, and bilayer polymorphic changes. Second, we will evaluate the effects of SS peptides on the structure and function of membranes from yeast and mammalian models. This will establish the sites of peptide interaction in the morphologically complex mitochondrion, how peptides affect the stability and assembly of membrane complexes, the distribution of lipids within mitochondria, and lipid turnover kinetics. Finally, using mitochondrial and cellular models, we will analyze the mechanisms by which SS peptides restore function under pathological conditions including oxidative stress, high calcium load, and amyloidogenic proteins involved in type II diabetes and Alzheimer’s disease. By this multi-tiered approach, our results will yield unprecedented insights into the mechanism of this class of therapeutics with particular relevance to aging-related diseases. Further, our peptide screen will inform the design of SS peptide variants with greater efficacy and/or bioavailability.