Role of arginine deficiency in pathogenesis of lupus

精氨酸缺乏在狼疮发病机制中的作用

• 批准号: 6804405
• 负责人: MINORU SATOH
• 金额: $ 7.28万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-25 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6804405
• 关键词: SDS polyacrylamide gel electrophoresis; aminoacid analyzer; aminoacid metabolism; antibody specificity; arginase; arginine; autoimmunity; enzyme linked immunosorbent assay; genetically modified animals; immunopathology; immunoprecipitation; laboratory mouse; mass spectrometry; pathologic process; polymerase chain reaction; protein deficiency; small nuclear RNA; small nuclear ribonucleoproteins; systemic lupus erythematosus; western blottings

DESCRIPTION (provided by applicant): Immunological characteristics of systemic lupus erythematosus (SLE) include polyclonal B-cell activation and production of specific autoantibodies. However, the autoimmune response is highly restricted to only a few antigens, indicating that there are mechanisms to specifically select target antigens. Autoantibodies to small nuclear ribonucleoproteins (snRNPs: Sm and nRNP) are frequently produced in SLE, MRL mice, and pristane-treated normal mice. In pristane-treated mice, the U1-70K, which has an unusually high arginine content (21%), appears central to the autoimmune process. Arginine is consumed by activated macrophages and arginases in inflammatory sites. In addition, L-canavanine, a non-protein amino acid homologue of L-arginine present in higher plants, may be efficiently incorporated into proteins, producing aberrant proteins that could create cryptic epitopes capable of triggering autoimmunity. In this study, we will investigate why U1 snRNPs are selectively targeted in pristane-induced lupus. We hypothesize that the arginine-rich U1-70K is aberrant in arginine-deficient pristane granulomas, generating cryptic epitopes that initiate autoimmunity. In aim 1, whether arginine is deficient in pristane-treated mice will be examined by amino acids analysis. Arginine metabolism (uptake, consumption, and reconversion) also will be evaluated. In Aim 2, U1-70K synthesized in arginine-deficient conditions and in the presence of L-canavanine in vitro will be evaluated for modifications by immunoprecipitation, amino acid analysis, and mass spectrometry. U1-70K from cells in pristane-treated mice also will be examined. In Aim 3, whether aberrant UlsnRNPs (arginine-deficient, L-canavanine containing) can trigger a specific autoimmune response will be investigated by immunizing mice with purified UlsnRNPs or apoptotic cells derived from these conditions.

描述（由申请人提供）：系统性红斑狼疮 (SLE) 的免疫学特征包括多克隆 B 细胞激活和特异性自身抗体的产生。然而，自身免疫反应高度局限于少数抗原，这表明存在特异性选择靶抗原的机制。 SLE、MRL 小鼠和经降植烷处理的正常小鼠经常产生针对小核核糖核蛋白（snRNP：Sm 和 nRNP）的自身抗体。在降植烷处理的小鼠中，U1-70K 的精氨酸含量异常高 (21%)，似乎是自身免疫过程的核心。精氨酸被炎症部位活化的巨噬细胞和精氨酸酶消耗。此外，L-刀豆氨酸是高等植物中存在的 L-精氨酸的非蛋白质氨基酸同源物，可以有效地掺入蛋白质中，产生异常蛋白质，从而产生能够触发自身免疫的隐性表位。在这项研究中，我们将研究为什么 U1 snRNPs 选择性地靶向降植烷诱导的狼疮。我们假设富含精氨酸的 U1-70K 在精氨酸缺乏的降植烷肉芽肿中是异常的，产生启动自身免疫的隐性表位。在目标 1 中，将通过氨基酸分析检查经降植烷处理的小鼠是否缺乏精氨酸。精氨酸代谢（摄取、消耗和再转化）也将被评估。在目标 2 中，将通过免疫沉淀、氨基酸分析和质谱法评估在精氨酸缺乏条件和 L-刀豆氨酸存在下体外合成的 U1-70K 的修饰情况。 来自降植烷处理小鼠细胞的 U1-70K 也将被检测。在目标 3 中，将通过用纯化的 UlsnRNP 或源自这些条件的凋亡细胞对小鼠进行免疫来研究异常的 UlsnRNP（缺乏精氨酸，含有 L-刀豆氨酸）是否可以触发特定的自身免疫反应。