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，尽管导致这一破坏性问题的机制尚未解决。我们确定，hRFRP-1，人RFamide相关肽-1，减缓心脏舒张，一个组成部分的阿托洛尔。这是一个令人兴奋的发现，因为它确定了一种可能导致舒张功能障碍的潜在内源性信号传导剂，因此可以作为潜在的治疗靶点。关于RF酰胺肽对心脏功能的影响的知识最初来自无脊椎动物心脏。存在人肽;然而，没有发表的研究报告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。获得的见解，然后可以用于治疗策略的未来发展，以减轻舒张功能障碍的影响。我们的初步目标是表征hRFRP-1对哺乳动物心肌细胞舒张的影响。长期目标是了解hRFRP-1在生理和病理生理条件下对心脏性能的作用，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中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末端和（2）与rfr-2结合来减缓肌细胞的舒张。我们证明了D。黑腹肌抑制素（DMS）减慢心率。DMS和hRFRP-1的C末端是相同的; C末端是DMS活性所必需的。DMS通过GPCR起作用，hRFRP-1与rfr-2结合。我们的目的是（#1）阐明hRFRP-1的结构-活性关系（SAR），和（#2）描绘hRFRP-1在肌细胞中的结合。SAR数据被用来设计激动剂和拮抗剂，并确认其对舒张功能的影响，并描绘hRFRP-1对舒张的影响所涉及的机制。配体-受体结合鉴定与hRFRP-1相互作用以抑制其信号的分子。目的1中使用的方法将是确定hRFRP-1的取代和截短的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的rfr-2表达并将可检测的hRFRP-1类似物结合至肌细胞蛋白。我们提出的研究填补了心血管生理学的一个重要科学空白;保守的神经肽如何减缓心脏舒张。长期目标是了解hRFRP-1在人类心脏中的作用，并将这些知识用于诊断和/或开发未来的治疗策略，以解决心血管疾病中的舒张功能障碍。公共卫生的相关性心脏的适当填充血液是至关重要的健康。血液充盈的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如何调节血液充盈，以开发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.