GATA4 C末端缺失增强心肌细胞凋亡影响心脏室间隔发育的信号转导机制

我们前期在先天性室间隔缺损（VSD）患者中发现并报道了7 个GATA4突变，其中p.S335X产生终止密码导致外显子5-6（Ex5-6）缺失。C端缺失的GATA4降低DNA结合力、抑制Bcl-2表达而促进心肌细胞凋亡，但机制尚不清楚。本课题拟以乳鼠心肌细胞和转基因小鼠模型研究：1）确定C末端缺失的GATA4诱导的细胞线粒体凋亡相关途径的信号通路分子；2）表达谱测序系统筛选和鉴定C末端缺失的GATA4调控心肌细胞凋亡的新的信号转导途径；3）探讨GATA4C末端影响DNA稳定性的机制；4）研究缺失C末端的GATA4对转基因小鼠心脏室间隔发育的分子机制。明确GATA4C末端增强心肌细胞凋亡影响心脏室间隔发育的机制，为探讨先天性心脏病临床产前分子诊断提供新的靶点。

Our previous mutational screening on patients with congenital ventricular septum defects (VSD) identified 7 mutations in GATA4 gene, of which, p.S335X pre-terminates the translation of GATA4, producing a truncated GATA4 that lacks exon 5-6 at c-terminus, referred as to GATA4-(ex5-6). We further demonstrated that GATA4-(ex5-6) presented a decreased affinity with its cis-elements and promoted apoptosis by suppression of bcl-2, an anti-apoptotic factor. In this proposal we intend to investigate the underlying mechanism in primarily cultured neonatal cardiomyocytes and transgenic mouse models. We specifically study 1) how GATA4-(ex5-6) triggers mitochondria apoptotic pathway, 2) through transcriptome sequencing, comprehensively seeking for the signaling molecules associated with GATA4-(ex5-6)-related apoptotic pathway, 3) how exon 5-6 affect the affinity and stability of its binding to cis-element, and 4) how GATA4-(ex5-6) causes VSD in vivo transgenic mouse model.