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: 6728653
• 负责人: MINORU SATOH
• 金额: $ 7.26万
• 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 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6728653
• 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细胞活化和特异性自身抗体的产生。然而，自身免疫反应高度局限于仅少数抗原，表明存在特异性选择靶抗原的机制。 小核核糖核蛋白（snRNP：Sm和nRNP）的自身抗体经常在SLE、MRL小鼠和降植烷处理的正常小鼠中产生。在降植烷处理的小鼠中，具有异常高的精氨酸含量（21%）的U1- 70 K似乎是自身免疫过程的核心。精氨酸被炎症部位的活化巨噬细胞和巨噬细胞酶消耗。此外，L-刀豆氨酸，一种存在于高等植物中的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，其可以产生能够触发自身免疫的隐蔽表位。在这项研究中，我们将研究为什么U1 snRNP在降植烷诱导的狼疮中被选择性靶向。我们假设富含精氨酸的U1- 70 K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蔽表位。在目的1中，将通过氨基酸分析来检查降植烷处理的小鼠中精氨酸是否缺乏。还将评价精氨酸代谢（摄取、消耗和再转化）。在目标2中，将通过免疫沉淀、氨基酸分析和质谱法评价在缺乏谷氨酰胺的条件下和存在L-刀豆氨酸的情况下体外合成的U1- 70 K的修饰。 还将检查降植烷处理小鼠中细胞的U1- 70 K。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免疫小鼠来研究异常的UlsnRNP（谷氨酰胺缺乏，含有L-刀豆氨酸）是否可以触发特异性自身免疫应答。