宫内高糖环境影响Apobec1介导的子代胰岛DNA去甲基化机制研究

妊娠期糖尿病（GDM）增加子代糖尿病发病风险，但机制不清。本课题组前期发现，GDM小鼠孕期治疗控制血糖后，仍无法消除子代糖代谢异常风险，原因是关键基因的DNA甲基化异常不能纠正。进一步高通量测序发现GDM胎鼠胰岛中DNA去甲基化关键酶Apobec1表达下调，提示应将GDM子代发病关注点聚焦于Apobec1对胰岛DNA去甲基化过程的影响及机制。本研究拟在此基础上，利用GDM小鼠模型，检测宫内高糖环境下胎鼠胰岛Apobec1表达水平、糖尿病通路关键基因表达和甲基化状态；利用胰岛特异性基因敲除小鼠研究Apobec1对胰岛发育中DNA甲基化的影响，阐明宫内高糖环境是否干扰Apobec1表达而影响子代糖尿病发病关键基因调控；体外细胞培养，纠正Apobec1异常表达，比较改善后对不良影响的消减作用；揭示宫内高糖环境导致子代糖尿病发病风险的可能机制，为实现从源头控制胎儿源性糖尿病提供新思路和理论基础。

Gestational diabetes mellitus (GDM) is associated with increased risk of diabetes in offspring. Animal studies have shown that glycemic control during pregnancy does not fully eliminate the risk of developing diabetes and restore the abnormal DNA methylation modification in offspring. In our previous study, high-throughput sequencing results showed that the expression of Apobec1, a key DNA demethylation enzyme, was down-regulated in the pancreatic islet of GDM fetal mice, indicating that the abnormal DNA demethylation might be associated with diabetes susceptibility in GDM offspring. On this basis, we will establish a GDM mouse model to detect Apobec1 level in the pancreatic islet of GDM offspring, and examine diabetes-related gene expression and DNA methylation levels. Using a Apobec1 knockout mouse, we will assess the effect of Apobec1 on DNA demethylation during pancreatic islet development, and on GDM-induced intergenerational susceptibility to diabetes. In vitro cell culture, gene overexpression technique will be conducted to correct abnormal Apobec1 expression, and then to analyze the attenuation of adverse effects. We are in hope of revealing the possible mechanism for GDM-induced diabetes susceptibility in offspring and provide a new idea and theoretical basis for the control of fetal originated adult diseases.