Does Demethylation of the Inactive X Contribute to Lupus in Women?

非活性 X 的去甲基化是否会导致女性狼疮？

• 批准号: 8045033
• 负责人: BRUCE C. RICHARDSON
• 金额: --
• 依托单位: VETERANS HEALTH ADMINISTRATION
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8045033
• 关键词: Affect; Animal Model; Autoantibodies; Autoimmune Diseases; Autoimmunity; B-Lymphocytes; CD4 Positive T Lymphocytes; CXCR3 gene; Cell physiology; Cells; DNA; DNA Methylation; DNA Sequence; Development; Disease; Epigenetic Process; Estrogens; Female; Flare; Frequencies; Gene Expression; Genes; Gonadal Steroid Hormones; Grant; Human; Immunoblotting; Individual; Klinefelter' s Syndrome; Link; Lupus; Methylation; MicroRNAs; Military Personnel; Modeling; Modification; Molecular; Mus; Pathogenesis; Predisposition; Prevalence; Production; Relative (related person); Reporting; Severities; Severity of illness; Signal Transduction; Systemic Lupus Erythematosus; T-Lymphocyte; TNFSF5 gene; Testing; Time; Transcript; Transfection; Turner' s Syndrome; UDP-N-acetylglucosamine-peptide beta-N-acetylglucosaminyltransferase; United States; Veterans; Woman; Work; X Chromosome; base; chemokine receptor; demethylation; design; effective therapy; environmental agent; inhibitor/antagonist; insight; lupus-like; male; men; mortality; new therapeutic target; novel; novel therapeutic intervention; novel therapeutics; overexpression

DESCRIPTION (provided by applicant): Systemic lupus erythematosus is a sometimes fatal autoimmune disease primarily affecting women. Estrogen contributes to disease severity, but does not completely explain the female predilection. Recent reports that men with Klinefelter's Syndrome (XXY) develop lupus at the same rate as women, while women with Turner's Syndrome (XO) are protected, suggests that having 2 X chromosomes is important for disease development. However, how a second X chromosome, which is largely inactivated, contributes to lupus in women is unclear. Evidence accumulated over more than 20 years indicates that lupus develops when genetically predisposed people are exposed to environmental agents that cause DNA demethylation in T cells, and that demethylated female T cells are sufficient to cause lupus-like autoimmunity. Work from the Richardson lab has shown that the B cell costimulatory molecule CD40L, encoded on the X chromosome and known to be overexpressed on lupus T cells, is overexpressed on T cells from women but not men with lupus because the gene on the inactive female X demethylates to cause biallelic expression, while men can only transcribe from one gene. Preliminary evidence suggests that demethylated T cells from women also overexpress other X chromosome genes including the chemokine receptor CXCR3, the signaling regulator OGT, and 6 microRNAs. Based on these observations we hypothesize that demethylation of genes on the inactive X predisposes women to lupus. We will test this hypothesis by: 1. Using high throughput DNA sequencing to compare methylation of CXCR3, OGT, the 6 miRNA genes and other X chromosome genes in CD4+ T cells from healthy men and women, with and without treatment with DNA methylation inhibitors, 2. Using high throughput DNA sequencing to compare methylation of CXCR3, OGT, the 6 miRNA genes and other X chromosome genes in CD4+ T cells from men and women with lupus matched for disease activity, 3. Determining the consequences of OGT overexpression on CD4+ T cell gene expression using transfections, microarrays and immunoblotting, and identify the miRNA target transcripts using Argonaute pulldowns followed by array analyses or sequencing, and 4. Determining if overexpressing CD40L, CXCR3, OGT or X chromosome miRNAs in a recently developed murine lupus model increases the severity of lupus in males to approximate the severity in females. We anticipate that these studies will confirm that women are predisposed to lupus in part because they can overexpress more genes than men, identify the molecules responsible, and thereby identify new therapeutic targets for women with lupus. PUBLIC HEALTH RELEVANCE: According to a recent estimate, SLE afflicts more than 130,000 individuals in the United States. Of these, nearly 90% are women, and women now comprise a significant number of military veterans. Current estimates reveal that the mortality rate of women with lupus is as high as 17.6 per million per year, indicating that current therapies are still imperfect. The design of more effective treatments will require a clear understanding of lupus pathogenesis. The studies described in this applicatiion will characterize molecular mechanisms predisposing women to lupus and thus may contribute to the design of safer and more effective therapies for this disease, and possibly for other autoimmune diseases that afflict our female veterans.

描述（由申请人提供）： 系统性红斑狼疮是一种有时致命的自身免疫性疾病，主要影响妇女。雌激素有助于疾病的严重程度，但不能完全解释女性的偏好。最近的报道称，患有克兰费尔特综合征（XXY）的男性与女性发展狼疮的速度相同，而患有特纳综合征（XO）的女性受到保护，这表明拥有2条X染色体对疾病发展很重要。然而，第二个X染色体，这是在很大程度上失活，如何有助于狼疮的妇女还不清楚。20多年来积累的证据表明，当遗传易感人群暴露于导致T细胞DNA去甲基化的环境因子时，狼疮就会发生，而去甲基化的女性T细胞足以引起狼疮样自身免疫。Richardson实验室的工作表明，B细胞共刺激分子CD 40 L，编码在X染色体上，已知在狼疮T细胞上过表达，在女性T细胞上过表达，但在患有狼疮的男性T细胞上不表达，因为不活跃的女性X染色体上的基因去甲基化导致双等位基因表达，而男性只能从一个基因转录。初步证据表明，来自女性的脱甲基T细胞也过表达其他X染色体基因，包括趋化因子受体CXCR3，信号调节剂OGT和6种microRNA。基于这些观察，我们假设非活性X染色体上的基因去甲基化使女性易患狼疮。我们将通过以下方式来检验这一假设：1。使用高通量DNA测序比较来自健康男性和女性的CD4+ T细胞中CXCR3、OGT、6个miRNA基因和其他X染色体基因的甲基化，使用和不使用DNA甲基化抑制剂治疗，2.使用高通量DNA测序比较来自疾病活动性匹配的男性和女性狼疮患者的CD4+ T细胞中CXCR3、OGT、6个miRNA基因和其他X染色体基因的甲基化。使用转染、微阵列和免疫印迹确定OGT过表达对CD4+ T细胞基因表达的影响，并使用Argonaute pulldown随后进行阵列分析或测序鉴定miRNA靶转录物，以及4.确定在最近开发的鼠狼疮模型中过表达CD40L、CXCR3、OGT或X染色体miRNA是否增加雄性狼疮的严重程度以接近雌性的严重程度。我们预计，这些研究将证实女性易患狼疮的部分原因是她们可以比男性过度表达更多的基因，确定负责的分子，从而为患有狼疮的女性确定新的治疗靶点。 公共卫生关系： 根据最近的估计，SLE在美国折磨超过130，000人。其中，近90%是女性，而且女性现在占退伍军人的很大一部分。目前的估计显示，患有狼疮的女性的死亡率高达每年百万分之17.6，这表明目前的治疗方法仍然不完善。设计更有效的治疗方法将需要对狼疮发病机制有清楚的了解。本申请中描述的研究将表征使女性易患狼疮的分子机制，因此可能有助于设计用于这种疾病的更安全和更有效的疗法，并且可能用于折磨我们的女性退伍军人的其他自身免疫性疾病。