Altered CD4+ T cell function in relation to the AHI1 MS locus

项目摘要/摘要 多发性硬化症(MS)是一种炎症性和神经退行性疾病，具有遗传和 环境成分对易感性的影响。全基因组无偏分离的易感基因座鉴定 联合研究(GWAS)是多发性硬化症(MS)的重要进展，但我们还不清楚 等位基因变异如何影响免疫功能。这一过渡仍然是 了解多发性硬化症和其他人类自身免疫性疾病。越来越多的证据表明 自身反应性CD4+T细胞在MS的病理生理学中起着核心作用。我们对110验证的MS的评估 使用一群健康的基因分型成年人的易感基因确定了改变附近基因的MS变异 在幼稚的CD4+T细胞中表达。我们很快将注意力集中在rs6908428单核苷酸上。 位于Abelson辅助整合位点1(AHI1)转录起始点附近的多态(SNP) 因为(I)该基因座与多发性硬化症的易感性密切相关(p=1.8×10-20)，(Ii) 与顶部可能包含因果变异的SNP处于强连锁不平衡(LD)的SNP很少 (3)易感等位基因rs6908428A对AHI1的RNA表达有很强的影响(1.12×10-107)。 但不在CD4+T细胞的相邻基因上(不是巧合重叠)，(Iv)AHI1在 致病性白介素17A产生的T细胞(Th17)与MS的发病机制有关 我们发现AHI1/AHI1与磷脂酶C(PLC)γ1结合 药物抑制PLCTh171抑制人γ细胞的增殖和小鼠模型 最后，在MS患者中，与MS患者相比，MS患者CD4+T细胞中AHI1 RNA的表达升高 健康受试者以及疾病活动性较高的MS患者外周血单核细胞中。 拟议项目的主要目标是：(1)鉴定以及体外和体外鉴定 参与调节CD_4~+T细胞AHI_1转录的因果变异体(S)的验证，(2)分析 Ahi1在小鼠CD4+T细胞中的功能及其对多发性硬化小鼠模型脑原性的影响，以及(3) 分析AHI1‘S对分型健康人Th17细胞基因网络的影响 格列泰治疗的MS患者(n=100)。因此，我们提出了一种多方面的方法，将人类 遗传和人类功能免疫学实验以了解易感基因如何改变状态 致病Th17的激活可以调节对MS的易感性，并加重疾病的严重性。

Project Summary/Abstract Multiple sclerosis (MS) is both an inflammatory and neurodegenerative disease that has genetic and environmental components to susceptibility. The identification of susceptibility loci by unbiased genome-wide association studies (GWAS) is a major step forward in multiple sclerosis (MS), but we do not yet understand how allelic variation influences immune function. This transition remains a major challenge in the understanding of MS and of other human autoimmune diseases. Increasing evidence suggests that autoreactive CD4+ T cells play a central role in MS pathophysiology. Our evaluation of the 110 validated MS susceptibility loci using a cohort of healthy genotyped adults identified MS variants that alter nearby gene expression in naïve CD4+ T cells. We quickly focused our attention on the rs6908428 single nucleotide polymorphism (SNP) located near the transcription start site of the Abelson helper Integration site 1 (AHI1) gene because (i) this locus is robustly associated with MS susceptibility (p=1.8 x 10-20), (ii) the “credible set” of SNPs in strong linkage disequilibrium (LD) with the top SNP that may contain the causal variant is small (n=11), (iii) the susceptibility allele rs6908428A has a strong effect on RNA expression of AHI1 (1.12 x 10-107) but not on neighboring genes in CD4+ T cells (not a coincidental overlap), (iv) AHI1 expression is induced in pathogenic interleukin (IL)-17A-producing T cells (Th17) that are implicated in MS pathogenesis and are well characterized in the laboratory and (v) we have discovered that Ahi1/AHI1 binds phospholipase C (PLC)γ1 and that pharmacological inhibition of PLCγ1 suppresses human Th17 cell proliferation and a mouse model of MS. Finally, in MS patients, AHI1 RNA expression is elevated in CD4+ T cells from MS patients compared to healthy subjects, as well as in PBMCs of MS patients with a higher disease activity. The principal goals of the proposed project are: (1) Identification as well as in vitro and ex vivo validation of causal variant(s) involved in the regulation of AHI1 transcription in CD4+ T cells, (2) analysis of Ahi1 function in murine CD4+ T cells and its influence on encephalitogenicity in a mouse model of MS, and (3) analysis of AHI1's influence on gene networks in human Th17 cells in genotyped healthy subjects (n=100), and glatiramer acetate-treated MS patients (n=100). We thus propose a multifaceted approach integrating human genetic and human functional immunology experiments to understand how the susceptibility loci alter the state of activation in pathogenic Th17 to modulate susceptibility to MS and aggravate disease severity.