OGT Overexpression in Women with Lupus

狼疮女性中 OGT 过度表达

• 批准号: 7510078
• 负责人: BRUCE C. RICHARDSON
• 金额: $ 19.7万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7510078
• 关键词: Acetylglucosamine; Affect; Age; Animal Model; Autoantibodies; Autoimmune Diseases; Autoimmunity; B-Lymphocytes; CD8B1 gene; Cell physiology; Cells; Cessation of life; Couples; DNA; DNA Methylation; Development; Diabetes Mellitus; Disease; Epigenetic Process; Estrogens; Female; Flare; Frequencies; Gene Expression; Genes; Genetic; Gonadal Steroid Hormones; Hexosamines; Hormonal Risk Factor; Human; Link; Lupus; MAPK14 gene; MAPK8 gene; Messenger RNA; Methylation; Modification; Nerve Degeneration; Pathway interactions; Patients; Pattern; Phosphorylation; Post-Translational Protein Processing; Predisposition; Prevalence; Production; Protein Dephosphorylation; Protein Overexpression; Proteins; Public Health; Risk; Role; Serine; Severities; Signal Pathway; Signal Transduction; Signaling Molecule; Surveys; Systemic Lupus Erythematosus; T-Lymphocyte; TNFSF5 gene; Testing; Threonine; Time; Transgenes; Transgenic Mice; UDP-N-acetylglucosamine-peptide beta-N-acetylglucosaminyltransferase; Woman; X Chromosome; base; bisulfite; demethylation; disability; insight; male; men; prevent

DESCRIPTION (provided by applicant): Lupus afflicts women 9 times more often than men. Estrogen contributes to lupus severity, but does not completely explain the increased risk. Impaired DNA methylation, a repressive epigenetic modification, causes overexpression of T cell genes that contribute to lupus. DNA methylation also silences one X chromosome in women. CD40LG is an X-linked gene known to be overexpressed in lupus and contribute to autoantibody production. We found that CD40LG on the inactive X demethylates and is overexpressed in women but not men with lupus, predisposing women to lupus. Other X-linked genes may also demethylate, predisposing to autoimmunity. We surveyed methylation sensitive T cell genes, and identified O-linked N-acetylglucosamine transferase (OGT) as another X-linked gene overexpressed in demethylated female T cells. OGT couples N-acetylglucosamine (GlcNAc) to serines and threonines in a variety of proteins including signaling molecules, modifying function in a manner analogous to phosphorylation and referred to as the hexosamine signaling pathway (HSP). HSP abnormalities are implicated in diabetes and neurodegeneration, but little is known regarding its role in T cells. We hypothesize that demethylation of OGT on the inactive X results in overexpression in women, altering HSP signaling and contributing to pathogenic T cell function by modifying signaling. We will test this hypothesis by: 1) Comparing OGT mRNA and protein levels in control and demethylated CD4+ and CD8+ T cells from healthy men and women with levels in CD4+ and CD8+ T cells from men and women with inactive lupus, active lupus, and disease/age controls, and confirming OGT demethylation by bisulfite sequencing, 2) Determining if OGT overexpression impairs T cell ERK, JNK and/or p38 pathway signaling and modifies T cell gene expression patterns, and 3) Determining the functional significance of T cell OGT overexpression on the development of autoimmunity using transgenic mice with a T cell specific inducible OGT transgene. These studies will characterize a new pathway regulating T cell gene expression, and characterize how abnormalities in the pathway may predispose women to autoimmunity. PUBLIC HEALTH RELEVANCE: Lupus is an autoimmune disease primarily affecting women, causing disability and sometimes death. The reason women are predisposed to lupus is unknown. Our group has found that a mechanism regulating gene expression, called DNA methylation, is defective in T lymphocytes from lupus patients, causing overexpression of genes that make the cells attack the body. This contributes to lupus in those with the appropriate genetic makeup. Women have 2 X chromosomes, while men have only one. One X chromosome is inactivated by DNA methylation in women to prevent them from expressing the genes twice as much as men. However, genes on the second X chromosome demethylate in women with lupus, causing overexpression of genes that may contribute to their disease. We have found that OGT, an X chromosome gene important in regulating cellular function, doubles expression in T lymphocytes from women when DNA methylation is inhibited. This suggests that OGT may also be overexpressed in women with lupus, contributing to their disease. The studies described in this application will determine if women with lupus overexpress OGT, and determine the functional consequences. The results may provide new insights into mechanisms causing autoimmunity in women, and suggest new ways to treat the disease.

描述（由申请人提供）：狼疮比男性多9倍。雌激素有助于狼疮的严重程度，但不能完全解释风险增加。 DNA甲基化受损（一种抑制性表观遗传学修饰）会导致造成狼疮的T细胞基因的过表达。 DNA甲基化也使女性中的一个X染色体沉默。 CD40LG是一种X连锁基因，已知在狼疮中过表达并有助于自身抗体的产生。我们发现CD40LG在无活性的X脱甲基甲酯上，并且在女性但没有狼疮的男性中过表达，使女性诱发了狼疮。其他X连锁基因也可能脱甲基化，易于自身免疫性。我们调查了甲基化敏感的T细胞基因，并鉴定出O-连接的N-乙酰葡萄糖转移酶（OGT）是在脱甲基化的雌性T细胞中过表达的另一个X连锁基因。 OGT夫妻夫妻在多种蛋白质中的丝氨酸和苏氨酸（包括信号分子）中的N-乙酰葡萄糖（GlcNAC）伴侣，以类似于磷酸化的方式修饰功能，并被称为甲状腺素信号通路（HSP）。 HSP异常与糖尿病和神经变性有关，但在T细胞中的作用知之甚少。我们假设OGT对非活动X的脱甲基化导致女性过表达，改变HSP信号传导并通过修饰信号传导来改变致病性T细胞功能。我们将通过：1）比较来自健康男性和女性的对照和脱甲基化的CD4+和脱甲基化的CD4+和CD8+ T细胞中的OGT mRNA和蛋白质水平，来自CD4+和CD8+ T细胞中的健康水平的男性和女性，患有狼疮，活性狼疮，活性狼疮，疾病/年龄对照，并确定OGT OGGT的cellition bisulation bisulition，2）IF MISERIST，2） JNK和/或p38途径信号传导并修改T细胞基因表达模式，以及3）使用具有T细胞特异性诱导型OGT Transgene的转基因小鼠，确定T细胞OGT过表达对自身免疫性开发的功能意义。这些研究将表征调节T细胞基因表达的新途径，并表征途径异常如何使妇女偏爱自身免疫性。 公共卫生相关性：狼疮是一种自身免疫性疾病，主要影响妇女，导致残疾甚至死亡。妇女易于忍受狼疮的原因尚不清楚。我们的小组发现，一种调节基因表达的机制（称为DNA甲基化）在狼疮患者的T淋巴细胞中有缺陷，导致使细胞攻击人体的基因过表达。这有助于具有适当遗传构成的人的狼疮。女人有2 x染色体，而男人只有一个。一个X染色体被DNA甲基化在女性中被灭活，以防止其表达基因的两倍。然而，狼疮女性的第二个X染色体脱甲基甲基化的基因导致可能导致其疾病的基因过表达。我们发现，当DNA甲基化被抑制时，OGT（X染色体基因对调节细胞功能很重要）会使女性T淋巴细胞的表达增加一倍。这表明OGT在患有狼疮的女性中也可能过表达，从而导致其疾病。本应用中描述的研究将确定狼疮女性是否过表达OGT，并确定功能后果。结果可能会提供有关导致女性自身免疫性机制的新见解，并提出了治疗疾病的新方法。