细胞凋亡相关基因APAF1/CASP9与人类神经管畸形的相关性研究

Normal cell proliferation and apoptosis are essential for neural tube closure during early stage of embryo development. Using next generation and whole genome sequencing techniques, we performed mutation screening on 363 and 100 NTDs (neural tube defects) patients, respectively. The results indicated plenty of rare mutations are significantly enriched on programmed cell death pathway. CASP9 and APAF1 are core members of apoptosis pathway, and they interact with each other to cleave the pro-caspase-9. In this study, we identified 5 and 4 rare mutations in APAF1 and CASP9 genes (2 recurrent mutations in CASP9), respectively, which are absent in 865 control groups. Thus, we speculate APAF1/CASP9 mutations are associated with human NTDs. Although model organisms research indicated APAF1/CASP9 knock out mice have typical phenotypes of NTDs, this relationship has been not confirmed in human so far. This project focuses on 9 rare mutations in APAF1/CASP9 genes and aims to study the association between APAF1/CASP9 gene and human neural tube defects, which further expand our knowledge on mechanism of apoptosis-related NTDs.

细胞增殖和凋亡等过程的均衡是胚胎发育期神经管正常闭合的基础。我们应用二代靶向和全基因组测序技术分别对363例和100例神经管畸形(NTDs)患者进行筛查，发现细胞凋亡通路相关基因有大量突变。CASP9是凋亡的关键酶，APAF1是其激活因子，二者功能密切相关。我们在APAF1和CASP9基因中分别检测到5个和4个NTD患者特有的突变位点(CASP9中有2个突变重复出现)，而在865例正常对照中均未出现。提示APAF1和CASP9基因突变与人类NTDs发生高度相关。已有报道APAF1和CASP9基因敲除小鼠均出现露脑和颅裂畸形，但在人群中的致病性目前尚无研究。本项目拟针对筛查出的9个突变，以小鼠神经前体细胞、人胚胎干细胞和斑马鱼为模型，寻找APAF1 /CASP9基因变异导致人类神经管畸形发生的生物学证据，并阐明其致病机制，从而从细胞凋亡角度深化对NTD发生机制的理解。