Structure function and ligand binding of a novel peptide involved in cardiac rela

描述（由申请人提供）：舒张功能障碍是发病率和死亡率的主要原因，尽管导致这一毁灭性问题的机制仍未解决。我们确定hRFRP-1，人类rfamily相关肽-1，减缓心脏舒张的一个组成部分。这是一个令人兴奋的发现，因为它确定了一种潜在的内源性信号剂，可能有助于舒张功能障碍，因此可以作为潜在的治疗靶点。关于RFamide肽对心脏功能影响的知识最初来自无脊椎动物的心脏。人肽存在；然而，没有发表的研究报道其在哺乳动物肌细胞或心肌中的功能。长期目标是将这些知识转化为人类，并了解这种肽在放松中的作用。所获得的见解可用于未来治疗策略的发展，以减轻舒张功能障碍的影响。我们最初的目标是表征hRFRP-1对哺乳动物肌细胞松弛的影响。长期目标是了解hRFRP-1在生理和病理生理条件下对心脏功能的作用，以及与人类心血管健康的相关性。这是作为R21提交的，以探索高影响力研究的潜力，因为我们将我们在黑腹果蝇的工作转化为哺乳动物系统，并最终转化为人类。这里测试的假设是hRFRP-1通过(1)其C端和(2)与rfr-2的结合减缓肌细胞的松弛。我们证明了黑胃肌抑制素（DMS）会减慢心率。DMS与hrfrp - 1c末端相同；C端是DMS活性所必需的。DMS通过GPCR起作用，hRFRP-1与rfr-2结合。我们的目标是：(1)阐明hRFRP-1的结构-活性关系（SAR），(2)描述hRFRP-1在肌细胞中的结合。SAR数据用于设计激动剂和拮抗剂，确认它们对舒张功能的影响，并描述hRFRP-1对舒张作用的机制。配体-受体结合识别hRFRP-1与之相互作用以转导其信号的分子。目的1中使用的方法是确定hRFRP-1的取代和截断肽类似物对松弛的影响。目的2中使用的方法将是研究心肌细胞中rfr-2的表达，并将可检测的hrfr -1类似物与心肌细胞蛋白结合。我们提出的研究填补了心血管生理学的重要科学空白；一个保守的神经肽是如何减缓心脏放松的。长期目标是了解hRFRP-1在人类舒张中的作用，并将这些知识应用于诊断和/或制定未来的治疗策略，以解决心血管疾病的舒张功能障碍。心脏的适当充血对健康至关重要。充血问题可能导致心力衰竭，导致疾病和死亡。我们的目标是了解大脑和心脏是如何调节血液充盈的，从而开发出治疗或药物来解决这个问题。

DESCRIPTION (provided by applicant): Diastolic dysfunction is a leading cause of morbidity and mortality, although the mechanism(s) responsible for this devastating problem remain unresolved. We determined that hRFRP-1, human RFamide-related peptide-1, slows cardiac relaxation, a component of diastole. This is an exciting finding as it identifies a potential endogenous signaling agent that could contribute to diastolic dysfunction, and therefore serve as a potential therapeutic target. Knowledge about the influence of RFamide peptides on cardiac function initially came from the invertebrate heart. The human peptide exists; however, no published studies report its function in mammalian myocytes or myocardium. A long term goal is to translate this knowledge to humans and understand the role of this peptide in relaxation. Insight gained may then be used for the future development of therapeutic strategies to lessen the impact of diastolic dysfunction. Our initial goal is to characterize the influence of hRFRP-1 on relaxation in mammalian myocytes. Longer term goals are to understand the role of hRFRP-1 on cardiac performance under physiological and pathophysiological conditions, and relevance to human cardiovascular health. This is submitted as an R21 to explore the potential for high impact research as we translate our work in Drosophila melanogaster to mammalian systems, and ultimately humans. The hypothesis tested here is hRFRP-1 slows relaxation in myocytes via (1) its C terminus and (2) binding to rfr-2. We demonstrated D. melanogaster myosuppressin (DMS) slows heart rate. DMS and hRFRP-1 C termini are identical; the C terminus is required for DMS activity. DMS acts through a GPCR, and hRFRP-1 binds to rfr-2. Our aims are to (#1) elucidate hRFRP-1 structure-activity relationship (SAR), and (#2) delineate hRFRP-1 binding in myocytes. SAR data are used to design agonists and antagonists and confirm their influence on diastolic function, and to delineate mechanisms involved in the effect of hRFRP-1 on relaxation. Ligand- receptor binding identifies the molecule that hRFRP-1 interacts with to transduce its signal. The approach used in aim 1 will be to determine the influence of substituted and truncated peptide analogs of hRFRP-1 on relaxation. The approach used in aim #2 will be to investigate rfr-2 expression in cardiac myocytes and bind a detectable hRFRP-1 analog to myocyte proteins. Our proposed research fills an important scientific gap in cardiovascular physiology; how a conserved neuropeptide acts to slow cardiac relaxation. A long-term goal is to understand the role of hRFRP-1 in human diastole and apply this knowledge for diagnosis and/or to develop future therapeutic strategies to address diastolic dysfunction in cardiovascular disease. PUBLIC HEALTH RELEVANCE The proper filling of the heart with blood is crucial to health. Problems in filling with blood may lead to heart failure causing illness and death. Our goal is to understand how blood filling is regulated by the brain and the heart to develop therapies or drugs to combat this problem.