Endothelial subpopulations in heart valve development and congenital heart disease

心脏瓣膜发育和先天性疾病中的内皮细胞亚群 项目摘要 正常的心脏瓣膜结构和成分是在发育过程中建立的，并且是先天性的 瓣膜畸形，例如由结构蛋白基因突变引起的畸形，如马凡综合征 (MFS)，随着时间的推移，会出现进行性的组织紊乱和功能障碍。粘液瘤性瓣膜病(MVD)是 以瓣叶增厚和进行性退化为特征，导致瓣膜返流 并降低了心脏功能。而与血流有关的脉动机械力作用在瓣叶上 在发育和疾病中，这些力量如何影响瓣膜结构和功能尚不清楚。 分子水平。单细胞RNA测序(ScRNAseq)显示瓣膜内皮细胞 亚群位于心脏瓣膜小叶的区域，具有不同的血流轮廓。这些VEC中的一个 表达机械敏感转录因子Prox1的亚群，但其在心脏瓣膜中的作用 发育、动态平衡和疾病都是未知的。此外，Prox1表达式被扩展到 报告有瓣膜返流的MFS小鼠模型中粘液瘤瓣膜的层流侧。我们 假设心脏血管内皮细胞中Prox1的表达受Wnt/β-连环蛋白激活的影响，对瓣膜至关重要 开发过程中的小叶组织，以及用于维护阀门结构和ECM组织 成年人。其目的是：1)确定Prox1在心脏瓣膜发育和动态平衡中的需要。 2)确定Prox1在粘液瘤瓣叶中的错误定位是否有助于巨噬细胞的渗透和 微血管病变进展。3)确定瓣膜内皮细胞中的Wnt/β-catenin信号是否需要定位 PROX1表达与内皮连接成熟这些研究的长期目标是确定 心脏瓣膜发育和病理重塑的机械敏感调节机制 导致了粘液瘤瓣膜病新的非手术治疗方法的发展。

Endothelial Subpopulations in Heart Valve Development and Congenital Disease Project Summary Normal heart valve structure and composition are established during development, and congenital valve malformations, such as those arising from mutations in structural protein genes as in Marfan syndrome (MFS), have progressive disorganization and dysfunction over time. Myxomatous valve disease (MVD) is characterized by thickening and progressive degeneration of valve leaflets, leading to valvular regurgitation and reduced heart function. While fluctuating mechanical forces related to blood flow act on the valve leaflets in development and disease, it is not known how these forces affect valve structure and function at the molecular level. Single cell RNA sequencing (scRNAseq) demonstrated valve endothelial cell (VEC) subpopulations localized in regions of heart valve leaflets with distinct blood flow profiles. One of these VEC subpopulations expresses Prox1, a mechanosensitive transcription factor, but its roles in heart valve development, homeostasis, and disease are unknown. Moreover, Prox1 expression is expanded to the laminar flow side of myxomatous valves in a mouse model of MFS with reported valve regurgitation. We hypothesize that Prox1 expression in heart VECs, subject to Wnt/β-catenin activation, is critical for valve leaflet organization during development and for maintenance of valve structure and ECM organization in adults. The Aims are: 1) Determine the requirements for Prox1 in heart valve development and homeostasis. 2) Determine if Prox1 mislocalization in myxomatous valve leaflets contributes to macrophage infiltration and MVD progression. 3) Determine if Wnt/beta-catenin signaling in valve endothelial cells is required for localized Prox1 expression and endothelial junction maturation. The long-term goals of these studies are to define mechanosensitive regulatory mechanisms of heart valve development and pathologic remodeling, thus leading to the development of new nonsurgical therapeutic approaches for myxomatous valve disease.