Environmental effects on lupus T cell DNA methylation and gene expression

描述(由申请人提供)： 低甲基化T细胞异常过表达甲基化敏感基因CD11a、干扰素-γ、执行和CD70参与了人类狼疮的发病过程。该小组最近的研究表明，与急性冠状动脉综合征(不稳定心绞痛和心肌梗死)有关的KIR基因也是甲基化敏感的，并在狼疮T细胞上过度表达。初步研究表明，通过限制叶酸或蛋氨酸，或通过直接/特异性抑制剂、信号抑制剂或SAH降低DNA甲基转移酶(DNMT)的活性，可以增加甲基化敏感T细胞基因的表达，这些作用是相加的。此外，补充蛋氨酸或叶酸可以减少或防止这些抑制剂对甲基化敏感基因的过度表达。这些结果表明，环境异源物质影响转移酶水平或功能导致的DNMT表达减少，加上饮食的影响，是影响甲基化敏感基因表达的相加因素，并最终导致狼疮及其并发症的发生。这些结果还表明，饮食中补充一种或多种与DNA甲基化有关的营养素可能具有保护作用。这些假说将通过比较以下因素来检验：1)营养限制/补充和DNA甲基化抑制剂单独和联合使用对T细胞CD11a、CD70、干扰素-γ、穿孔素和KIR的表达和甲基化的影响，并确定对巨噬细胞和内皮细胞的细胞毒性的后果；2)体外营养限制和补充对狼疮患者和正常对照组T细胞甲基化敏感基因的表达和甲基化敏感基因的影响；3)对照、甲基供体缺乏和富甲基饮食对由可诱导的ERK信号通路缺陷引起的自身免疫小鼠T细胞基因甲基化敏感的表达和狼疮严重程度的影响。有证据表明，饮食修改可以改善体外异常基因表达和小鼠模型中的疾病严重程度，这将导致将这些结果扩展到狼疮患者的研究。

DESCRIPTION (provided by applicant): Hypomethylated T cells aberrantly overexpressing the methylation sensitive genes CD11a, IFN-gamma, perform and CD70 have been implicated in the pathogenesis of human lupus. Recent studies from this group demonstrate that KIR genes, implicated in acute coronary syndromes (unstable angina and myocardial infarctions), are also methylation sensitive and overexpressed on lupus T cells. Preliminary studies suggest that methylation sensitive T cell gene expression can be increased by restricting either folate or Met, or by decreasing DNA methyl transferase (DNMT) enzyme activity with direct/specific inhibitors, signaling inhibitors, or SAH, and that these effects are additive. Further, supplementation with either Met or folate decreases or prevents overexpression of the methylation sensitive genes by these inhibitors. These results suggest that decreases in DNMT expression due to environmental xenobiotics affecting transferase levels or function, together with dietary influences, are additive in affecting methylation sensitive gene expression, and ultimately causal in the development of lupus and its complications. These results also suggest that dietary supplementation of one or more nutrients involved in DNA methylation may be protective. These hypotheses will be tested by comparing the effects of: 1) nutrient restriction/supplementation and DNA methylation inhibitors alone and in combination on the expression and methylation of T cell CD11a, CD70, IFN-gamma, perforin and KIR and determining the consequences on cytotoxicity for macrophages and endothelial cells, 2) nutrient restriction and supplementation in vitro on the expression and methylation of methylation sensitive genes in T cells from subjects with lupus and normal controls, and 3) control, methyl-donor deficient, and methyl-rich diet on the expression of methylation sensitive T cell genes and lupus severity in mice with autoimmunity caused by an inducible ERK pathway signaling defect. Evidence that dietary modification can ameliorate aberrant gene expression in vitro and disease severity in the murine model will lead to studies extending these results to lupus patients.