Functional Characterization of Phosphodiesterase 1 in Single Ventricle Heart Disease

项目摘要 这份有指导的临床科学家发展奖提案描述了一项为期5年的培训计划，以使Dr。 Nakano(PI)有机会在儿科心力衰竭领域发展学术生涯。中野博士 已在科罗拉多大学完成了儿科心脏病学临床奖学金和基础心血管 通过T32机制进行研究性培训。中野博士的职业抱负是成为一名独立的 内科科学家，通过分子研究改善儿科心力衰竭的预后。 单室性心脏病(SV)是先天性心脏病的一种亚型，在没有心脏的情况下是致命的 干预。进行性心力衰竭是心脏移植常见的死亡原因和适应症。 在患有SV的儿童中。SV HF背后的确切机制尚不清楚，限制了 找出有效的治疗方法。已证实的成人心力衰竭药物对儿童心力衰竭人群的外推 没有成功，因此需要新的治疗范例。 选择性磷酸二酯酶(PDE)的药物抑制已变得越来越常见 室性心衰的治疗，主要目的是通过增加环腺苷来增强收缩能力 单磷酸(CAMP)和PDE3抑制(PDE3i)。然而，我们的研究表明，在分子水平上， PDE3i对先天性心衰不是有效的治疗方法；这与PDE3i在儿科发现的情况形成了鲜明的对比 扩张型心肌病所致心力衰竭患者。因此，有必要阐明其他PDE在 心脏，特别是PDE1：1)PDE1是主要的cAMP-和环鸟苷一磷酸(CGMP)- 在胞浆中水解PDE，2)PDE1定位于肌节，可能针对一个独特的 3)PDE1抑制(PDE1i)可减少cGMP途径介导的肥大。在这 建议，我们将确定：1)PDE1在移植的SV心肌中的定位和活性，并测量 急性PDE1i对SV小梁的功能影响；2)PDE1在钙敏感性和松弛中的作用 室性心动过速心肌细胞和肌原纤维的动力学；3)PDE1在病理中的作用 用SV受试者血清处理新生大鼠心肌细胞的重塑。澄清 PDE1在SV心肌中的分子和功能作用为发展PDE1i提供了依据 用于这一人群的临床使用，目前的结果很差，令人无法接受。PDE1i疗法可能 在这些高危的心动过速患者中，有可能防止心衰的发生或推迟心脏移植的需要。 在一个最佳的、有指导的环境中，中野博士将获得新的研究专业知识，这些专业知识将对 以独立研究员的身份开展未来的心血管转化性研究。中野医生有 支持加州大学的临床、研究、儿科和成人心脏病学专业知识和资源 科罗拉多州，包括该大学的大型人体心脏组织库。中野博士将继续与她合作 目前在科罗拉多大学的导师团队，他们致力于她的成功。

Project Summary This Mentored Clinical Scientist Development Award proposal describes a 5-year training program to allow Dr. Nakano (PI) the opportunity to develop an academic career in the field of pediatric heart failure. Dr. Nakano has completed clinical pediatric cardiology fellowship at the University of Colorado and basic cardiovascular research training through a T32 mechanism. Dr. Nakano’s career aspiration is to become an independent physician scientist and improve outcomes in pediatric heart failure through molecular investigations. Single ventricle heart disease (SV) is a subset of congenital heart defects that are universally fatal without intervention. Progressive heart failure (HF) is a common cause of death and indication for heart transplantation in children with SV. The exact mechanisms underlying SV HF are poorly understood, limiting the ability to identify effective therapies. The extrapolation of proven adult HF medications to the pediatric SV HF population has been unsuccessful, consequently novel treatment paradigms are needed. Pharmacologic inhibition of select phosphodiesterase (PDE) enzymes has become increasingly common therapy for SV HF, with the primary goal of augmenting contractility through increasing cyclic adenosine monophosphate (cAMP) with PDE3 inhibition (PDE3i). However our studies suggest that, on a molecular level, PDE3i is not effective therapy in SV HF; this is in stark contrast to what is found with PDE3i in pediatric patients with HF due to dilated cardiomyopathy. Thus, it is necessary to elucidate the role of other PDEs in the heart, particularly PDE1: 1) PDE1 is the predominant cAMP- and cyclic guanosine monophosphate (cGMP)- hydrolyzing PDE in the cytosol, 2) PDE1 is localized to the sarcomere and likely targets a unique pool of cAMP, and 3) PDE1 inhibition (PDE1i) decreases hypertrophy mediated through cGMP pathways. In this proposal, we will determine: 1) PDE1 localization and activity in explanted SV myocardium, and measure the functional effects of acute PDE1i in SV trabeculae; 2) the role of PDE1 in calcium sensitivity and relaxation kinetics in myocytes and myofibrils isolated from SV myocardium; and 3) the contribution of PDE1 in pathologic remodeling using neonatal rat ventricular myocytes treated with sera from SV subjects. Elucidating the molecular and functional role of PDE1 in the SV myocardium would provide justification for developing PDE1i for clinical use in this population, where current outcomes are unacceptably poor. PDE1i therapy could potentially prevent HF development or delay the need for heart transplantation in these high-risk, SV patients. Within an optimal, mentored environment, Dr. Nakano will gain new research expertise that will be essential to conducting future translational cardiovascular research as an independent investigator. Dr. Nakano has the support of clinical, research, pediatric, and adult cardiology expertise and resources at the University of Colorado, including the University’s large human heart tissue bank. Dr. Nakano will continue to work with her current mentor team at the University of Colorado, who are committed to her success.