Genetic and Immunological Impact of the HRES-1/Rab4 Locus in SLE

HRES-1/Rab4 位点对 SLE 的遗传和免疫学影响

• 批准号: 7651497
• 负责人: Andras Perl
• 金额: $ 27.48万
• 依托单位: UPSTATE MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7651497
• 关键词: 1q42; Adaptor Signaling Protein; Alleles; Autoantibodies; Autoimmunity; B-Lymphocytes; Binding; Biological Assay; CD3 Antigens; CD4 Antigens; Cell membrane; Chimeric Proteins; Chloroquine; Chromosome Pairing; Chromosomes, Human, Pair 1; Chronic; Complex; Confocal Microscopy; DNA Binding; Data; Dendritic Cells; Development; Disease; Dominant-Negative Mutation; Early Endosome; Endosomes; Enhancers; Enterotoxins; Environmental Risk Factor; Exons; Functional disorder; GTP Binding; Gene Expression; Genes; Genetic; Genetic Transcription; Genetic Variation; Genomics; Genotype; Genus staphylococcus; Glutathione S-Transferase; Guanosine Triphosphate Phosphohydrolases; HERVs; Haplotypes; Human; IRF1 gene; Immunoprecipitation; Inflammatory; Jurkat Cells; Link; Linkage Disequilibrium; Long Terminal Repeats; Lupus; MHC Class II Genes; Maps; Membrane; Membrane Microdomains; Microsatellite Repeats; Organelles; Other Genetics; Peptides; Peripheral Blood Lymphocyte; Personal Satisfaction; Play; Protein Overexpression; Proteins; Recycling; Rheumatoid Arthritis; Role; Site; Small Interfering RNA; Superantigens; Surface; Synapses; Systemic Lupus Erythematosus; T-Cell Activation; T-Lymphocyte; Testing; Time; Toxic Shock Syndrome Toxin-1; Transcript; Transcriptional Activation; Transducers; Transfection; Transferrin Receptor; Western Blotting; ZAP-70 Gene; base; chromatin immunoprecipitation; functional outcomes; immunological synapse; inhibitor/antagonist; peripheral blood; promoter; rab4A Protein; receptor; research study; response; segregation; trafficking; ubiquitin ligase

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease characterized by circulating antinuclear autoantibodies and dysfunction of T and B lymphocytes. Both genetic and environmental factors are believed to influence development of the disease. We detected and cloned the HRES-1 human endogenous retrovirus, mapped it to chromosome 1 at q42, newly identified six haplotypes in the long terminal repeat (LTR), and revealed an association of polymorphic HindIII653C-containing alleles with SLE. Thus, HRES-1 or a gene in linkage disequilibrium with this locus may influence autoimmunity in SLE. A newly discovered 2,986-base antisense transcript encodes exon 1 of a 24 kD protein, HRES-1/Rab4, that regulates surface expression of CD4, and to a lesser extent, expression of the transferrin receptor (TFR) through endosome recycling. Overexpression of HRES-1/Rab4 reduces surface expression of CD4 by inhibition of endocytic recycling and targets CD4 for lysosomal degradation, while dominant-negative HRES-1/Rab4S27N has the opposite effect both in Jurkat cells and peripheral blood T cells. HRES-1/Rab4 and CD4 protein levels inversely correlate both in healthy and lupus PBL. CD4 protein levels are reduced, while HRES-1/Rab4 expression is increased in lupus T cells having at least one HindIII653C in the HRES-1 LTR. CD4 plays essential roles in formation of the immunological synapse (IS) during normal T-cell activation by a cognate MHC class II peptide complex. The key intracellular transducer of T-cell activation, Lck, is brought to the IS via binding to CD4. TCR? chain binds to the TFR. Abnormal T cell responses in SLE have been associated with reduced TCR? chain and Lck levels in the lipid rafts of the IS. Although the regulatory roles of Rab GTP-ases in endosome trafficking are well recognized, their involvement in T-cell activation is largely unknown. Under Specific Aim 1, we will test the hypothesis that HRES1/Rab4 regulates the composition of lipid rafts, the assembly of the T cell synapse, and the functional outcomes of T-cell activation in peripheral blood T cells and Jurkat cells when stimulated with CD3 or superantigen. Under Specific Aim 2 we will determine the role of increased HRES-1/Rab4 expression in the altered lipid raft composition of lupus T cells. Under Specific Aim 3, we will test the hypothesis that the HindIIIG653C allele, alone or in combination with other genetic factors of lupus-associated haplotypes, enhances the expression of HRES-1/Rab4.

系统性红斑狼疮（SLE）是一种慢性炎症性疾病，其特征是循环性抗核细胞增多。 自身抗体和 T 淋巴细胞和 B 淋巴细胞功能障碍。遗传和环境因素均被认为 来影响疾病的发展。我们检测并克隆了HRES-1人内源性逆转录病毒， 将其映射到 1 号染色体的 q42，在长末端重复 (LTR) 中新识别出 6 个单倍型，以及 揭示了含有 HindIII653C 的多态性等位基因与 SLE 的关联。因此，HRES-1 或基因 该位点的连锁不平衡可能影响 SLE 的自身免疫。新发现的2,986个碱基 反义转录物编码 24 kD 蛋白 HRES-1/Rab4 的外显子 1，该蛋白调节表面表达 CD4，并在较小程度上通过内体循环表达转铁蛋白受体 (TFR)。过度表达 HRES-1/Rab4 通过抑制内吞循环来减少 CD4 的表面表达 以 CD4 为目标进行溶酶体降解，而显性失活 HRES-1/Rab4S27N 则具有相反的作用 Jurkat 细胞和外周血 T 细胞。 HRES-1/Rab4 和 CD4 蛋白水平呈负相关 健康和狼疮 PBL。狼疮中 CD4 蛋白水平降低，而 HRES-1/Rab4 表达增加 HRES-1 LTR 中具有至少一个 HindIII653C 的 T 细胞。 CD4在细胞的形成中起着重要作用 正常 T 细胞激活期间由同源 MHC II 类肽复合物激活的免疫突触 (IS)。这 T 细胞激活的关键细胞内转导器 Lck 通过与 CD4 结合而被带到 IS。 TCR？链式捆绑 到 TFR。 SLE 中 T 细胞反应异常与 TCR 降低有关？链和 Lck 电平 在IS的脂筏中。尽管 Rab GTP 酶在内体运输中的调节作用已得到充分证实 众所周知，它们在 T 细胞激活中的作用在很大程度上是未知的。在具体目标 1 下，我们将测试 假设 HRES1/Rab4 调节脂筏的组成、T 细胞突触的组装，以及 外周血 T 细胞和 Jurkat 细胞中 T 细胞激活的功能结果 CD3 或超抗原。在具体目标 2 下，我们将确定 HRES-1/Rab4 表达增加的作用 狼疮 T 细胞脂筏组成发生改变。在具体目标 3 下，我们将检验以下假设： HindIIIG653C 等位基因，单独或与狼疮相关单倍型的其他遗传因素组合， 增强 HRES-1/Rab4 的表达。