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

• 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
• 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' 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

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、CD 4 T细胞和骨髓细胞在自身免疫性疾病（如系统性红斑狼疮（SLE））的发展中起关键作用，并可参与自身抗体和细胞因子产生、组织损伤和释放的自身抗原激活的病理刺激网络。我们的建议集中在自身免疫性疾病中的CD 4 T细胞和骨髓细胞。新技术增加了我们对SLE等疾病的遗传基础的理解，并帮助确定了强大的易感基因座，如MHC。最近的全基因组测序揭示了人类遗传变异的详细目录，每个人约有12，000个基因变异。我们对SLE或其他自身免疫性疾病中免疫细胞中失调的信号传导途径以及基因变异（非同义SNP）如何支持异常免疫特征的知识要少得多。在这里，我们结合联合收割机的分子，细胞和体内的方法来了解CD 4 T细胞的自身免疫功能，这些T细胞是如何纠缠在一个刺激环与骨髓细胞，以及如何微妙的单等位基因，非同义SNP的患者可以导致强大的自身免疫表型。 在初步结果中，我们提出了一种新的小鼠模型，Rasgrp 1Anaef，在Ras激活Rasgrp 1点突变，导致自身免疫表型。T细胞发育的彻底表征表明，Rasgrp 1Anaef T细胞有效发育，Rasgrp 1Anaef小鼠没有淋巴细胞减少。相反，由于基础Rasgrp 1Anaef-mTOR信号传导增加，CD 44 hiCXCR 5 + PD 1 + CD 4 + T细胞异常积聚，骨髓细胞亚群数量增加，小鼠显示ANA（抗核抗体）和蛋白尿。Rasgrp 1Anaef/WT杂合子小鼠也表现出自身免疫性病理，因此一个Rasgrp 1 WT等位基因不能补偿Rasgrp 1Anaef。我们提出了一个最近发表的晶体结构的自身抑制Rasgrp 1二聚体，并证明Rasgrp 1Anaef可以形成一个二聚体与Rasgrp 1 WT蛋白，提出了一个行动机制如何单等位基因RasGRP 1变体，报告在SLE患者，自身免疫性（1型）糖尿病，和格雷夫斯病，可以有一个生物学效应。 在这里，我们将研究异常积累的Rasgrp 1Anaef T细胞的免疫特征（目标1），T-，B-和骨髓细胞之间的密切相互作用和Rasgrp 1Anaef骨髓细胞在Rasgrp 1Anaef自身免疫特征中的作用（目标2），以及这种Rasgrp 1Anaef小鼠模型如何作为单等位基因，非同义RasGRP 1 SNP等位基因的范例（目标3）。密切相关但独立的目标的结果将增加我们对具有看似无辜和微妙的SNP变体的T细胞和骨髓细胞如何通过病理刺激网络驱动自身免疫的理解，以及RasGRP 1中的单等位基因遗传SNP事件如何可能导致自身免疫病理学的理解。