Loss of Intrinsic Control in Autoimmune T Helper Cells with Signaling Variants

具有信号变异的自身免疫 T 辅助细胞失去内在控制

基本信息

批准号：
9237188
负责人：
JEROEN ROOSE
金额：
$ 38.69万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-03-01 至 2019-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9237188
关键词：
Alleles Amino Acid Substitution Amino Acids Antigen Presentation Antinuclear Antibodies Autoantibodies Autoantigens Autoimmune Diseases Autoimmune Process Autoimmune Responses Autoimmunity B-Lymphocytes Biological CD4 Positive T Lymphocytes Catalogs Catalytic Domain Cells Cellular Assay Complex Crystallization Defect Development Dimerization Disease Ethylnitrosourea Event FRAP1 gene Gene Deletion Genes Genetic Genetic Polymorphism Genetic Variation Goals Graves&apos Disease Helper-Inducer T-Lymphocyte Human Human Genetics IgE Immune Immune Cell Activation Immune System Diseases Immunologics Inherited Insulin-Dependent Diabetes Mellitus Knowledge Lead Lymphocyte Lymphopenia Mission Modeling Molecular Mus Mutagenesis Mutant Strains Mice Mutation Myelogenous Myeloid Cells Pathologic Pathology Patients Persons Phenotype Phosphotransferases Play Point Mutation Process Production Proteins Proteinuria Publishing RNA Splicing Reporting Research Research Personnel Role Signal Pathway Signal Transduction Signaling Molecule Single Nucleotide Polymorphism Structure Susceptibility Gene Systemic Lupus Erythematosus T-Cell Activation T-Cell Development T-Lymphocyte Techniques Tissues Tyrosine United States National Institutes of Health Variant ZAP-70 Gene autoimmune arthritis cytokine dimer genetic variant genome sequencing immune activation in vivo insight interest mouse model novel novel strategies public health relevance whole genome

项目摘要

DESCRIPTION (provided by applicant): B cells, CD4 T cells, and myeloid cells play a critical role in the development of autoimmune diseases such as systemic lupus erythematosus (SLE) and can be engaged in a pathologic stimulatory network of autoantibody and cytokine production, tissue damage, and activation by released self-antigens. Our proposal is centered on CD4 T- and myeloid- cells in autoimmune diseases. New techniques have increased our understanding of the genetic basis of diseases like SLE and helped identify robust susceptibility loci, such as MHC. Recent whole genome sequencing has revealed a detailed catalog of the human genetic variation with a very high occurrence of ~12,000 gene variants per person. Much less robust is our knowledge of dysregulated signaling pathways in immune cells in SLE or other autoimmune diseases and how gene variants (non-synonymous SNPs) may underpin abnormal immune features. Here we combine molecular-, cellular-, and in vivo- approaches to understand the autoimmune features of CD4 T cells, how these T cells are entangled in a stimulatory loop with myeloid cells, and how subtle monoallelic, non-synonymous SNPs in patients can result in robust autoimmune phenotypes. In Preliminary Results, we present a novel mouse model, Rasgrp1Anaef, with a point mutation in the Ras activator Rasgrp1 that causes an autoimmune phenotype. Thorough characterization of T cell development demonstrates that Rasgrp1Anaef T cells develop effectively and Rasgrp1Anaef mice are not lymphopenic. Instead, CD44hiCXCR5+PD1+ CD4+ T cells aberrantly accumulate due to increased basal Rasgrp1Anaef- mTOR signaling, numbers of myeloid cell subsets increase, and mice show ANA (anti-nuclear antibodies) and proteinuria. Rasgrp1Anaef/WT heterozygous mice also demonstrate autoimmune pathology, thus one Rasgrp1WT allele cannot compensate for Rasgrp1Anaef. We present a recently published crystal structure of an autoinhibitory Rasgrp1 dimer and demonstrate that Rasgrp1Anaef can form a dimer with a Rasgrp1WT protein, presenting a mechanism of action for how monoallelic RasGRP1 variants, reported in patients with SLE, autoimmune (Type 1) diabetes, and Graves disease, can have a biological effect. Here we will investigate the immune character of the aberrantly accumulating Rasgrp1Anaef T cells (Aim 1), the intimate interaction between T-, B-, and myeloid cells and the role of Rasgrp1Anaef myeloid cells in the Rasgrp1Anaef autoimmune features (Aim 2), and how this Rasgrp1Anaef mouse model may serve as a paradigm for monoallelic, non-synonymous RasGRP1 SNP alleles (Aim 3). Results from the strongly related but independent aims will increase our understanding of how T cells and myeloid cells with seemingly innocent and subtle SNP variants can drive autoimmunity through a pathological stimulatory network, and how monoallelic genetic SNP events in RasGRP1 may cause autoimmune pathology.

描述（由申请人提供）：B细胞、CD4 T细胞和骨髓细胞在系统性红斑狼疮（SLE）等自身免疫性疾病的发展中发挥着关键作用，并且可以参与自身抗体和细胞因子产生的病理刺激网络，组织损伤和释放的自身抗原激活。我们的提案集中于自身免疫性疾病中的 CD4 T 细胞和骨髓细胞。新技术增加了我们对 SLE 等疾病遗传基础的了解，并帮助识别 MHC 等强大的易感位点。最近的全基因组测序揭示了人类遗传变异的详细目录，每人大约有 12,000 个基因变异的发生率非常高。我们对系统性红斑狼疮或其他自身免疫性疾病免疫细胞信号通路失调以及基因变异（非同义 SNP）如何支持异常免疫特征的了解还不够深入。在这里，我们结合分子、细胞和体内方法来了解 CD4 T 细胞的自身免疫特征，这些 T 细胞如何与骨髓细胞纠缠在刺激环中，以及患者体内微妙的单等位基因、非同义 SNP 如何发挥作用导致强大的自身免疫表型。在初步结果中，我们提出了一种新型小鼠模型 Rasgrp1Anaef，其 Ras 激活剂 Rasgrp1 中存在点突变，可导致自身免疫表型。 T 细胞发育的全面表征表明 Rasgrp1Anaef T 细胞有效发育，并且 Rasgrp1Anaef 小鼠不存在淋巴细胞减少。相反，由于基础 Rasgrp1Anaef-mTOR 信号传导增加，CD44hiCXCR5+PD1+ CD4+ T 细胞异常积累，骨髓细胞亚群数量增加，小鼠表现出 ANA（抗核抗体）和蛋白尿。 Rasgrp1Anaef/WT 杂合小鼠也表现出自身免疫病理学，因此 Rasgrp1WT 等位基因不能补偿 Rasgrp1Anaef。我们展示了最近发表的自抑制 Rasgrp1 二聚体的晶体结构，并证明 Rasgrp1Anaef 可以与 Rasgrp1WT 蛋白形成二聚体，提出了单等位基因 RasGRP1 变异如何在 SLE、自身免疫性（1 型）糖尿病和糖尿病患者中报告的作用机制。格雷夫斯病可以产生生物学效应。在这里，我们将研究异常积累的 Rasgrp1Anaef T 细胞的免疫特征（目标 1）、T 细胞、B 细胞和骨髓细胞之间的密切相互作用以及 Rasgrp1Anaef 骨髓细胞在 Rasgrp1Anaef 自身免疫特征中的作用（目标 2），以及Rasgrp1Anaef 小鼠模型如何作为单等位基因、非同义 RasGRP1 的范例SNP 等位基因（目标 3）。强烈相关但独立的目标的结果将加深我们对看似无辜且微妙的 SNP 变异的 T 细胞和骨髓细胞如何通过病理刺激网络驱动自身免疫，以及 RasGRP1 中的单等位基因 SNP 事件如何导致自身免疫病理的理解。