Naturally occurring canine myxomatous mitral valve disease as a large animal model for human non-syndromic mitral valve prolapse

项目摘要 非综合征性二尖瓣脱垂（MVP）是一种常见的心脏瓣膜病，影响2-3%的人类 人群中，可导致二尖瓣关闭不全、心功能不全、充血性心力衰竭，甚至猝死。 由于缺乏药物治疗来管理这种疾病，MVP目前通过手术干预治疗。 对医疗管理的有效策略的发展一直受到不完全理解的阻碍 疾病病理生理学，特别是关于驱动瓣膜间质细胞（VIC）分化的因素 从成纤维细胞到成肌纤维细胞样细胞，导致粘液瘤病理。此外，转基因 忠实地概括人类MVP病理学的动物模型是不可用的，部分原因是相对的， 遗传因素的复杂性与疾病易感性有关。有趣的是，MVP（也称为 粘液瘤性二尖瓣变性）经常发生在犬中，估计发生率大于 百分之五十先前对犬和人MVP的比较表明，它们有几个关键的组织病理学特征， 这些特征表明自发性犬疾病可能代表了良好的转化模型。使用犬 以MVP为模板，我一直在研究细胞外囊泡（EV）和miRNAs在 驱动成纤维细胞向成肌细胞转变。EV是膜结合的细胞来源的颗粒，用于细胞间的相互作用。 通过蛋白质和非编码（nc）RNA的转移进行信号传导，并且它们与 包括阿尔茨海默氏症和癌症在内的几种疾病的传播。我们的初步数据显示犬类受害者 来自患病瓣膜的细胞产生不同的无细胞miRNA和EV相关的ncRNA特征， 正常阀门因此，该提议的假设是，犬MVP可以用于研究 EV信号介导的驱动粘液瘤性瓣膜变性的因子，其最终目标是 鉴定和验证用于早期检测和治疗干预的新靶点。完成 为此，我将首先在组织病理学和分子水平上完成犬MVP的表征， 与人MVP直接比较，然后询问EV和ncRNA介导的信号传导对维克的影响 基因表达谱和功能。这些数据将有助于更全面地了解EV- 介导的信号传导影响MVP的进化，并创建一个蓝图，纳入自发犬 MVP进入转化管道，以优化早期检测和干预的新方法。富人 塔夫茨大学及其合作伙伴的研究环境，包括兽医学院，医学， 塔夫茨医学中心，塔夫茨临床转化科学研究所， 麻省理工学院确保获得成功完成拟议工作所需的资源和专业知识。 我在工程和医学心脏病学方面的培训与我的指导团队的指导相结合， 在人类心脏病学、比较医学、EV/ncRNA生物学和生物信息学/生物统计学方面的专业知识， 我很好地定位，成功地过渡到一个独立的临床科学家。

PROJECT SUMMARY Non-syndromic mitral valve prolapse (MVP), a common valvular heart disease affecting 2-3% of the human population, can lead to mitral regurgitation, cardiac dysfunction, congestive heart failure and even sudden death. Given the lack of medical therapeutics to manage this disease, MVP is currently treated by surgical intervention. Development of effective strategies for medical management has been hindered by an incomplete understanding of disease pathophysiology, specifically regarding factors that drive differentiation of valve interstitial cells (VICs) from fibroblast- to myofibroblast-like cells, resulting in myxomatous pathology. Furthermore, genetically modified animal models that faithfully recapitulate human MVP pathology are unavailable, in part due to the relative complexity of genetic factors found to be associated with disease predisposition. Interestingly, MVP (also termed myxomatous mitral valve degeneration) occurs frequently in dogs with an estimated incidence of greater than 50%. Previous comparisons of canine and human MVP demonstrated that they share several key histopathologic features suggesting that the spontaneous dog disease may represent a good translational model. Using canine MVP as a template, I have been investigating the potential role of extracellular vesicles (EVs) and miRNAs in driving the fibroblast to myoblast switch. EVs are membrane-bound cell-derived particles used for inter-cell signaling through the transfer of proteins and noncoding (nc)RNA, and they have been implicated in the propagation of several diseases including Alzheimer's and cancer. Our preliminary data show that canine VICs from diseased valves produce different cell-free miRNA and EV-associated ncRNA signatures than cells from normal valves. As such, the hypothesis underlying this proposal is that canine MVP can be leveraged to study EV-signaling mediated factors that drive myxomatous valve degeneration, with the ultimate goal of identifying and validating novel targets for early detection and therapeutic intervention. To accomplish this, I will first complete the characterization of canine MVP at the histopathologic and molecular levels with a direct comparison to human MVP, and then interrogate the impact of EV and ncRNA mediated signaling on VIC gene expression profiles and function. These data will facilitate a more complete understanding of how EV- mediated signaling influences the evolution of MVP and create a blueprint for incorporating spontaneous canine MVP into the translational pipeline to optimize novel approaches for early detection and intervention. The rich research environment at Tufts University and its partners including schools of Veterinary Medicine, Medicine, Nutrition and Graduate Sciences, Tufts Medical Center, the Tufts Clinical Translational Sciences Institute, and MIT ensure access to the resources and expertise necessary for successful completion of the proposed work. My training in engineering and medical cardiology combined with guidance from my mentoring team bridging expertise in human cardiology, comparative medicine, EV/ncRNA biology and bioinformatics/biostatistics makes me well positioned to successfully transition to an independent clinician-scientist.