核小体组装蛋白1样1(Nap1l1)调控斑马鱼胚胎心脏发生的分子机制研究

Mechanistic study of cardiogenesis is crucial to clarify the pathogenesis of congenital heart diseases. Reawakening signaling pathways that are active during heart growth and development might also offer exciting opportunities for effective therapies for impaired adult heart. Previous studies from our laboratory in mouse P19CL6 embryonic carcinoma cells and induced pluripotent stem cells confirmed that reduced expression of the nucleosome assembly protein 1-like 1 (Nap1l1) effectively enhance cardiac mesoderm induction and cardiomyocyte formation, however, whether this protein is an active signaling molecule during embryonic heart development and its function are unclear. The preliminary results in this project indicated the abundant expression of zebrafish Nap1l1 in embryonic heart and that its downregulation produces embryonic ventricular sudden contraction and atrial enlargement phenotype, but its regulatory mechanism remains to be further explored. Our hypothesis is proposed that zebrafish Nap1l1 may be involved in mesoderm induction and embryonic heart development. Taking advantages of the zebrafish models (such as nap1l1 gene mutant and conditionally overexpressing Nap1l1 fish lines) and relevant techniques (such as in situ hybridization, confocal imaging, and genetic epistatic effect analysis), we will explore the critical role and regulatory mechanisms of Nap1l1 in embryonic heart development from the molecular, cellular and whole animal level. This study will lay the foundation for the discovery of novel signaling pathways involved in heart development, and provide new ideas for further elucidation of the pathogenesis of congenital heart disease and impaired adult heart repairement.

心脏发生的机制研究不仅能阐明先心病的发病机理，通过唤醒心脏发生期活跃的信号通路也可能是修复受损成年心脏的有效方法。 本实验室前期以小鼠畸胎瘤细胞P19CL6和诱导多潜能干细胞为模型证实下调核小体组装蛋白1样1（Nap1l1）表达能增强中胚层诱导和心肌细胞形成，但该蛋白是否是胚胎心脏发生中活跃的信号分子及其功能尚不清楚。 本课题前期结果显示斑马鱼Nap1l1在胚胎心脏表达丰富,下调Nap1l1表达产生心室骤缩和心房扩大表型，其作用机制有待进一步阐明。 我们提出假说：斑马鱼Nap1l1参与中胚层诱导和心脏发生。 我们将通过nap1l1基因突变体和条件性过表达等斑马鱼模型，采用原位杂交、激光共聚焦成像和遗传学上位效应分析等手段，从分子、细胞和在体水平探讨Nap1l1在心脏发生中的作用和调控机制，为发现新的心脏发生相关信号通路奠定基础,为进一步阐明先心病的发病机理和成年心脏修复提供新思路。

心脏发生的机制研究不仅能阐明先心病的发病机理，通过唤醒心脏发生期活跃的信号通路也可能是修复受损心脏的有效方法。 本项目探寻核小体组装蛋白1样1（Nap1l1）在胚胎心脏发生中的功能及其分子机制。 本课题利用生物信息学、胚胎整体原位杂交和启动子分析等，明确了斑马鱼nap1l1在胚胎心室肌细胞表达丰富而在成体心肌细胞基本不表达。 我们通过吗啡啉抑制剂、nap1l1基因突变体和条件性过表达等斑马鱼模型，采用原位免疫荧光和激光共聚焦成像等手段，证实阻抑Nap1l1蛋白表达会导致胚胎心室骤缩和心房扩大、心室肌小梁缺陷，为进一步阐明先心病的发病机理和成年心脏修复提供新思路。