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的潜在机制的重要一步。几种遗传变异与多种疾病有关，表明这些疾病中存在共同的机制。其中一种基因变体是PTPN 22 1858 T。这种变异与T1 D、RA、Graves病、重症肌无力和SLE相关。这种变体导致磷酸酶Lyp R620 W中的单个氨基酸变化，导致功能的显性增益。我们和其他人已经证明，这种变体导致通过T细胞受体对激活的迟钝反应，这表明这种变体可能增强个体对自身免疫的易感性的机制。在这项研究中，我们提出了一个假设，即LypR 620 W变体导致的受损的T细胞受体信号传导以一种有利于通过产生促炎细胞因子、对AICD的抵抗和外周血中CD 4记忆T细胞群的扩增来发展促炎记忆反应的方式塑造CD 4 T细胞功能。我们将这些研究集中在可以对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。我们将讨论Lyp R620 W变体对体外人CD 4 T细胞的分化、谱系定型、增殖和存活的影响，并建立该变体改变免疫应答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异体的个体与不携带疾病相关变异体的相似匹配受试者对接种与载体蛋白CRM 197缀合的肺炎球菌疫苗的应答，来解决这种变异体对体内免疫应答的总体影响。这将首先在健康受试者中进行，然后是T1 D个体研究。 我们提出在三个具体目标中这样做：目标1）我们将通过对来自携带风险变体的健康对照的T细胞进行体外实验，来解决PTPN 22 1858 T变体在分离时的功能影响。目的2）我们将检验具有PTPN 22 1858 T等位基因的个体在体内抗原攻击后产生增强的促炎记忆T细胞应答的假设。目的3）我们将检查与LypR 620 W变体相关的表型如何在体外和体内自身免疫性糖尿病的背景下表达，然后我们将这些研究扩展到PTPN 22 1858 T变体对这些受试者中胰岛特异性T细胞应答的影响。 公共卫生相关性：自身免疫性疾病是复杂的多基因疾病;识别与自身免疫相关的遗传变异的功能意义将极大地增强我们对驱动这些疾病的免疫机制的理解。在这项资助中，我们将研究与多种自身免疫性疾病相关的遗传变异PTPN 22 1858 T变异的影响。具体来说，我们将研究在携带该变体的个体中观察到的T细胞激活的钝化如何改变T细胞功能、生长和生存。

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. PUBLIC HEALTH RELEVANCE: Autoimmune diseases are complex polygenic diseases; identifying the functional significance of the genetic variants associated with autoimmunity will greatly enhance our understanding of the immune mechanisms that drive these diseases. In this grant we will study the impact of a genetic variant associated with multiple autoimmune diseases, the PTPN22 1858T variant. Specifically we will examine how the blunting of T cell activation, observed in individuals with the variant, alters T cell function, growth and survival.