Impact of the autoimmunity associated PTPN22 1858T

描述（由申请人提供）：最近的全基因组关联扫描已经鉴定出大量与自身免疫相关的基因。确定这些遗传变异的功能结果是理解这些疾病潜在机制的重要一步。一些遗传变异与多种疾病有关，表明这些疾病中有共同的机制在起作用。其中一个这样的基因变体是PTPN22 1858T。该变异与T1D、RA、Graves病、重症肌无力和SLE相关。这种变异导致磷酸酶Lyp R620W中单个氨基酸的改变，导致显性功能的增加。我们和其他人已经证明，这种变异会导致对T细胞受体激活的迟钝反应，这表明这种变异可能会增强个体对自身免疫的倾向。在这项研究中，我们提出了一个假设，即由LypR620W变异引起的T细胞受体信号受损，以一种有利于促炎记忆反应发展的方式塑造CD4 T细胞功能，通过产生促炎细胞因子，抵抗AICD和外周血中CD4记忆T细胞群的扩大。我们把这些研究的重点放在那些可以与人类受试者进行的研究上，因为这种单一氨基酸变化改变的分子相互作用可能是人类细胞所独有的。我们将探讨Lyp R620W变异对体外人类CD4 T细胞分化、谱系承诺、增殖和存活的影响，并建立这种变异改变免疫反应的潜在细胞和分子机制。然后，我们将通过比较携带疾病相关变体的个体与不携带疾病相关变体的相似匹配受试者接种结合载体蛋白CRM197的肺炎球菌疫苗的反应，来解决该变体对体内免疫反应的全球影响。这项研究将首先对健康受试者进行，然后对T1D患者进行研究。我们提出这样做有三个具体目标：目标1)我们将通过在体外对携带风险变体的健康对照的T细胞进行实验，解决PTPN22 1858T变体的分离功能影响。目的2)我们将验证具有PTPN22 1858T等位基因的个体在体内对抗原攻击产生增强的促炎记忆T细胞反应的假设。目的3)我们将研究与LypR620W变异相关的表型如何在体外和体内的自身免疫性糖尿病背景下表达，然后我们将这些研究扩展到PTPN22 1858T变异对这些受试者的胰岛特异性T细胞反应的影响。

DESCRIPTION (provided by applicant): Recent genome-wide association scans have resulted in the identification of a large number of genes which are associated with autoimmunity. Identifying the functional outcome of these genetic variants is an important step in understanding the underlying mechanisms of these diseases. Several genetic variants have been linked to multiple diseases, indicating that common mechanisms are at play in these diseases. One such genetic variant is the PTPN22 1858T. This variant is associated with T1D, RA, Graves Disease, myasthenia gravis and SLE. This variant leads to a single amino acid change in the phosphatase Lyp R620W, resulting in a dominant gain of function. We and others have demonstrated that this variant results in a blunted response to activation via the T cell receptor which suggests a mechanism by which this variant may enhance an individual's predisposition to autoimmunity. In this grant we propose to address the hypothesis that the impaired T cell receptor signaling resulting from the LypR620W variant shapes CD4 T cell function in a manner which favors the development of proinflammatory memory responses through the production of proinflammatory cytokines, a resistance to AICD and an expansion of the CD4 memory T cell population in the peripheral blood. We have focused these studies on those which can be performed with human subjects as the molecular interaction altered by this single amino acid change may be unique to human cells. We will address the impact that the Lyp R620W variant has on the differentiation, lineage commitment, proliferation and survival of human CD4 T cells in vitro and establish the underlying cellular and molecular mechanisms by which this variant alters the immune response. We will then address the global impact of this variant on the immune response in vivo by comparing the response to vaccination with pneumococcal vaccine conjugated to the carrier protein CRM197 in individuals who carry the disease associated variant to those of similarly matched subjects who do not. This will be done first with healthy subjects, followed by studies of individuals with T1D. We propose to do this in three specific aims: Aim 1) We will address the functional impact of the PTPN22 1858T variant in isolation, by performing experiments on T cells derived from healthy controls who carry the risk variant in vitro. Aim 2) We will test the hypothesis that individuals who possess the PTPN22 1858T allele develop an enhanced proinflammatory memory T cell response upon antigen challenge in vivo. Aim 3) We will examine how phenotypes associated with the LypR620W variant are expressed in the context of autoimmune diabetes in vitro and in vivo, then we will extend these studies to the impact of PTPN22 1858T variant on the islet specific T cell response in these subjects.