Dissection of the genetic and molecular underpinnings of heart valve development

心脏瓣膜发育缺陷占先天畸形的20%-30%。然而，在大多数情况下，潜在的遗传和分子原因尚未确定。越来越多的证据表明，控制正常心脏瓣膜发育的调节机制也有助于人体瓣膜的病理。我们最近发现，一个新的依赖蛋白激酶D2(PKD2)的信号通路通过控制HDA5-Notch1信号而参与心脏瓣膜发育的调控，该信号通路特异性地存在于房室管(AVC)的心内膜细胞中。在拟议的研究中，我们现在的目标是(1)研究PKD2-HDAC5-NOTCH1信号级联在体外和体内内皮细胞内皮细胞向间充质转化(EMT)的启动和进展中的作用。此外，我们的目标是(2)剖析新的斑马鱼心脏瓣膜突变尾巴的遗传和分子病理学。最后，我们的目标是(3)利用酵母双杂交技术鉴定心脏特异的拖尾相互作用组，并通过在斑马鱼中的过表达和敲除研究来在体内表征这些拖尾相互作用蛋白。总之，拟议的研究最终将有助于进一步剖析人类心脏瓣膜疾病的遗传病因和病理生理学，这对于开发更具体的治疗策略至关重要。

Defective development of heart valves accounts for in 20-30% of congenital malformations. However, in most cases, the underlying genetic and molecular causes have not been identified yet. There is increasing evidence that the regulatory mechanisms governing normal heart valve development also contribute to human valve pathology. We recently have shown that a novel Protein Kinase D2 (PKD2) dependent signalling pathway is involved in the regulation of cardiac valve development by controlling HDA5-Notch1 signaling specifically in endocardial cells of the atrioventricular canal (AVC). In the proposed research we now aim (1) to characterize the role of the PKD2-HDAC5-NOTCH1 signaling cascade on the initiation and progression of endothelial-to-mesenchymal transition (EMT) of endothelial cells in vitro and in vivo. Furthermore, we aim (2) to dissect the genetic and molecular pathology of the novel zebrafish heart valve mutant tailback. Finally, we aim (3) to identify the heart-specific tailback-interactome using yeast two hybrid technology and to in vivo characterize these tailback interacting proteins by overexpression and knock-down studies in zebrafish. In summary, the proposed research will ultimately help to further dissect the genetic etiology and pathophysiology of human heart valve diseases, which is essential for the development of more specific treatment strategies.