Department of Medical Science and Institute of Bioinformatics and Structural Biology, National Tsing Hua University, No.101, Sec.2, Kuang Fu Road, Hsinchu30013, Taiwan, R.O.C.
Cardiovasc Res. 2013 Mar 1;97(3):443-53. doi: 10.1093/cvr/cvs355. Epub 2012 Dec 4.
Cardiac valve disease is a common cause of congenital heart failure. Cardiac valve development requires a complex regulation of assorted protease activities. Nevertheless, the regulation of these proteases during atrioventricular (AV) valve formation is poorly understood. Previously, PRSS23, a novel vascular protease, is shown to be highly expressed at the AV canal during murine heart development; however, its function remains unknown. In this study, we sought to characterize the functional role of PRSS23 during cardiac valve formation.
We used a transgenic zebrafish line with fluorescently labelled vasculature as a tool to study the function of PRSS23. We first cloned the zebrafish prss23 and confirmed its sequence conservation with other vertebrate orthologues. Expression of prss23 was detected in the ventricle, atrium, and AV canal during zebrafish embryonic development. We found that morpholino knockdown of Prss23 inhibited the endothelial-to-mesenchymal transition (EndoMT) at the AV canal. Moreover, in human aortic endothelial cell-based assays, PRSS23 knockdown by short-hairpin RNA not only repressed the transforming growth factor-β-induced EndoMT, but also reduced Snail transcription, suggesting that Snail signalling is downstream of PRSS23 during EndoMT. We further demonstrated that human PRSS23 and SNAIL could rescue the prss23 morpholino-induced AV canal defect in zebrafish embryos, indicating that the function of PRSS23 in valvulogenesis is evolutionarily conserved.
We demonstrated for the first time that the initiation of EndoMT in valvulogenesis depends on PRSS23-Snail signalling and that the functional role of PRSS23 during AV valve formation is evolutionarily conserved.
心脏瓣膜病是先天性心力衰竭的常见原因。心脏瓣膜的发育需要各种蛋白酶活性的复杂调节。然而，房室（AV）瓣形成过程中这些蛋白酶的调节知之甚少。先前，一种新型血管蛋白酶 PRSS23 在鼠类心脏发育过程中在房室管高度表达，但功能未知。本研究旨在探讨 PRSS23 在心脏瓣膜形成过程中的功能作用。
我们使用带有荧光标记脉管系统的转基因斑马鱼系作为工具来研究 PRSS23 的功能。我们首先克隆了斑马鱼 prss23，并证实其与其他脊椎动物同源物的序列保守性。prss23 在斑马鱼胚胎发育过程中在心室、心房和房室管中表达。我们发现，PRSS23 形态发生抑制了房室管的内皮-间充质转化（EndoMT）。此外，在人主动脉内皮细胞基础实验中，短发夹 RNA 敲低 PRSS23 不仅抑制转化生长因子-β诱导的 EndoMT，而且降低了 Snail 转录，表明 Snail 信号在 EndoMT 过程中是 PRSS23 的下游。我们进一步证明，人 PRSS23 和 SNAIL 可挽救斑马鱼胚胎中 prss23 形态发生抑制导致的房室管缺陷，表明 PRSS23 在瓣膜形成中的功能在进化上是保守的。
我们首次证明了心脏瓣膜发生中 EndoMT 的启动依赖于 PRSS23-Snail 信号，并且 PRSS23 在房室瓣形成中的功能作用在进化上是保守的。
