PTPN22基因启动子多态性影响1型糖尿病易感性的机制研究

PTPN22 was one of the most important genes in the etiology of type 1 diabetes. Although PTPN22 was also associated with many other autoimmune diseases, the functional importance of this gene in disease susceptibility is not fully studied. In our previous large association study among Chinese Hans, we have identified that the association between PTPN22 and type 1 diabetes is located in the promoter region of the gene. In addition, variants in PTPN22 affect the expression of PTPN22 in peripheral blood. These results indicated that the promoter region of PTPN22 is likely involved in the regulation of PTPN22 expression which may further leads to altered susceptibility to autoimmune diseases. Therefore we proposed the current study to investigate the functional importance of genetic variations in this region regarding the regulation of PTPN22 expression. We will investigate the cis element in PTPN22 promoter and its binding transcriptional factors. Followed by investigation on the transcriptional regulation of the transcriptional factor, the proposed study can provide evidence on the expression regulation of PTPN22, which will line further a road to the intervention of immune regulation by manipulating the expression of PTPN22.

1型糖尿病（T1D）是一种多基因遗传疾病，其中PTPN22为其重要的致病基因，但其确切致病机制不清。我们之前进行的大样本相关性研究显示汉族儿童PTPN22的启动子区域与T1D相关，提示PTPN22启动子可能具有导致疾病易感的生物学功能。我们进而检测了儿童外周血淋巴细胞的PTPN22表达，发现启动子-2.7k处多态性可影响淋巴细胞PTPN22表达；凝胶迁移及质谱鉴定提示该多态性可影响T细胞系中转录因子STAT3与启动子的结合力。基于此，本申请将深入研究PTPN22启动子内可改变PTPN22表达的基因多态性位点；并采用凝胶迁移、质谱鉴定影响PTPN22基因转录的转录因子，进而通过转录因子过表达及shRNA载体研究PTPN22的转录调节，分析免疫细胞细胞因子的变化，探究该启动子区域多态性对PTPN22的调控及产生自身免疫相关性的机制，为靶向调控该基因表达及其基础上进行免疫调节治疗方法提供新思路。

本项申请研究目标为阐明 PTPN22 基因启动子区域单核苷酸多态性（single nucleotide polymorphism，SNP）和1型糖尿病相关性产生的潜在功能机制。经过项目的实施开展，对PTPN22启动子区域内多态性和细胞核蛋白结合能力进行了分析，对启动子所结合的蛋白进行了鉴定，发现PTPN22启动子区域内的SNP对转录因子结合的影响力较为微弱，以原计划试验方法对其分析所得到的结果不确定性较大，结合近期同领域内的其他研究结果，提示该基因影响1型糖尿病机制的研究需要更为成熟的试验方法。.在项目研究期间，我们在前期PTPN22启动子多态性和T1D相关性的基础上，进一步扩大了基因分析的范围，发现我国1型糖尿病患者新的易感位点并发表论文一篇。同时，在对临床工作中发现一例少见的可治愈的儿童糖尿病，通过对其发病及治疗机制的进一步研究，发表论文一篇。此外，通过本项目病毒转染试验方法的基础，结合近期1型糖尿病自身免疫机制研究的其他方向，我们初步建立了腺相关病毒对胸腺进行基因调节的方法，为T1D发生机制中胸腺作用的研究建立基础。