Fuctional Analyses of Autoimmune Disease Variants

该项目名为“自身免疫性疾病变异的功能分析”，主要研究人类和小鼠的三种1型糖尿病（T1D）易感位点CTLA4、PTPN22和CD226。T1D是一种主要的儿童疾病，其发病率稳步上升，且5岁以下儿童确诊人数不断增加，原因不明。提出的研究完全融入PPG的活动和目标，并提供了一个平台，继续在剑桥和波士顿的Pis之间进行高效，相互依存和协同合作，旨在了解T1D和自身免疫性疾病基因变异的生物学效应（我们已经通过遗传作图确定）。T1D基因变异将在离体研究中使用来自基因选择的本地健康志愿者（剑桥生物资源）的新鲜血液样本，并在体内研究精确设计的T1D NOD小鼠模型。

The project, Functional Analyses of Autoimmune Disease Variants, is focused on three type 1 diabetes (T1D) susceptibility loci, CTLA4, PTPN22 and CD226 in humans and in mice. T1D is a major disease of children with an unexplained steady rise in incidence and increasing numbers of children diagnosed under age 5 years. The research proposed is fully integrated into the PPG activities and goals, and provides a platform to continue the highly productive, interdependent and synergistic collaboration amongst the Pis in Cambridge and Boston aimed at understanding the biological effects of T1D and autoimmune disease gene variants (that we have identified using genetic mapping). T l D gene variants will be studied ex vivo using fresh blood samples from a major resource of genetically-selectable, local healthy volunteers (the Cambridge BioResource) and in vivo, in precisely engineered NOD mouse models of T1D. The Ctla4, Ptpn22 and Cd226 KO alleles will be used to develop NOD strains to model human T1D. A mouse Ptpn22 variant that increases T1D will be a focus of mechanistic studies on the PTPN22 gene, which is part of a molecular pathway that affects multiple human autoimmune diseases. T cells having the susceptibility allele at Ptpn22 have a higher threshold of activation and at a population level fewer of the cells produce IL-2 when stimulated ex vivo. Since both human and mouse gene variants in the IL-2 pathway affect T1D susceptibility, experiments to study gene-gene interactions between the PTPN22 and IL-2 pathways in both species are proposed. Preliminary data indicate that the susceptibility allele at CTLA4, which decreases the expression of soluble CTLA-4, reduces the probability that Tregs will be activated. Overexpression of soluble CTLA-4 in primary T cells and cell lines will be one approach used to study the mechanism by which soluble CTLA-4 affects early events in T cell activation. Since variants at both the PTPN22 and CTLA-4 genes are proposed to alter T cell activation, gene-gene interactions between the PTPN22 and CTLA-4 pathways in both humans and mice will be investigated.