Functional Characterization of Phosphodiesterase 1 in Single Ventricle Heart Disease

项目概要 该指导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. 中野（PI）有机会在儿科心力衰竭领域发展学术生涯。中野博士 已完成科罗拉多大学临床儿科心脏病学研究和基础心血管研究 通过T32机制进行研究培训。中野博士的职业抱负是成为一名独立的人 医师科学家并通过分子研究改善小儿心力衰竭的结果。 单心室心脏病 (SV) 是先天性心脏病的一个子集，如果不进行治疗，通常会致命。 干预。进行性心力衰竭（HF）是常见的死亡原因和心脏移植的指征 患有 SV 的儿童。 SV HF 的确切机制尚不清楚，限制了研究的能力 确定有效的疗法。将经过验证的成人心力衰竭药物外推至儿童 SV 心力衰竭人群 尚未成功，因此需要新的治疗范例。 选择性磷酸二酯酶 (PDE) 的药理学抑制已变得越来越普遍 SV HF 的治疗，主要目标是通过增加环腺苷来增强收缩力 单磷酸盐 (cAMP) 与 PDE3 抑制 (PDE3i)。然而我们的研究表明，在分子水平上， PDE3i 不是治疗 SV HF 的有效方法；这与儿科 PDE3i 的发现形成鲜明对比 扩张型心肌病引起的心力衰竭患者。因此，有必要阐明其他偏微分方程在 心脏，特别是 PDE1：1) PDE1 是主要的 cAMP- 和环磷酸鸟苷 (cGMP)- 水解细胞质中的 PDE，2) PDE1 定位于肌节，可能针对一个独特的池 cAMP，以及 3) PDE1 抑制 (PDE1i) 减少通过 cGMP 途径介导的肥大。在这个 根据建议，我们将确定：1) PDE1 在外植 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 从 SV 心肌中分离出的肌细胞和肌原纤维的动力学； 3) PDE1 在病理学中的贡献 使用经 SV 受试者血清处理的新生大鼠心室肌细胞进行重塑。阐明 PDE1 在 SV 心肌中的分子和功能作用将为开发 PDE1i 提供理由 用于该人群的临床使用，目前该人群的结果差得令人无法接受。 PDE1i 疗法可以 可能会预防心力衰竭的发生或延迟这些高危心室颤动患者进行心脏移植的需要。 在最佳的指导环境中，中野博士将获得新的研究专业知识，这对于 作为独立研究者进行未来的转化心血管研究。中野博士拥有 大学的临床、研究、儿科和成人心脏病学专业知识和资源的支持 科罗拉多州，包括该大学的大型人类心脏组织库。中野博士将继续与她合作 科罗拉多大学现任导师团队致力于帮助她取得成功。

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.