LINE1-ORF0 in SLE pathogenesis

SLE 发病机制中的 LINE1-ORF0

• 批准号: 10681876
• 负责人: Felipe Andrade
• 金额: $ 24.56万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-06 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10681876
• 关键词: 5' Splice Site; 5' Untranslated Regions; Address; Amino Acids; Antibodies; Antigen Targeting; Antigens; Autoantibodies; Autoantigens; Autonomous Replication; Chimeric Proteins; Clinical; Code; DNA Transposable Elements; DNA Transposons; Development; Disease; Elements; Endogenous Retroviruses; Enzyme-Linked Immunosorbent Assay; Etiology; Exons; Family; Foundations; Gene Expression Profile; Generations; Genes; Genetic Transcription; Genome; Genomic DNA; Genomics; Goals; Human; Human Genome; Hybrids; Immune; Immunoprecipitation; Infectious Agent; Interferons; Ku70 protein; Length; Link; Long Terminal Repeats; Mass Spectrum Analysis; Measures; Mediating; N-terminal; Nuclear; Nuclear Protein; Nucleic Acids; Nucleotides; Open Reading Frames; Outcome; Parasites; Pathogenesis; Patients; Peripheral Blood Mononuclear Cell; Prevalence; Prevention; Primates; Production; Proteins; RNA Splicing; RNA-Binding Proteins; RNA-Directed DNA Polymerase; Research Project Grants; Retroelements; Retrotransposon; Role; Signal Transduction; Source; Systemic Lupus Erythematosus; Tissues; Viral; Virus; Work; clinically significant; cohort; endonuclease; hybrid protein; immunogenicity; insight; interest; microbial; neoantigens; neutrophil; new therapeutic target; novel; novel diagnostics; novel therapeutics; peripheral blood; promoter; prospective; seropositive; systemic autoimmune disease

PROJECT SUMMARY/ABSTRACT Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease characterized by sustained interferon (IFN) signaling and high titer autoantibodies leading to immune-mediated tissue damage. An abnormal accumulation of nucleic acids derived from retrotransposons, a class of transposable element, has been linked to diseases characterized by sustained IFN-I production, such as SLE. In particular, retrotransposons of the non- LTR LINE1 (L1) family have been shown to be activated in patients with SLE. More recently, it was found that the RNA-binding protein (ORF1p) and the ORF2p endonuclease/reverse transcriptase encoded by L1s are SLE autoantigens, supporting the notion that L1 elements may play a role in SLE pathogenesis. This proposal is focused on the study of a recently discovered antisense open reading frame (ORF) found in the L1 5’UTR, termed ORF0. ORF0 encodes for a small nuclear protein (ORF0p) of 71 amino acid residues, which increases L1 mobility. ORF0 has several unique features, which may have critical implications on the potential mechanistic role of L1s in SLE pathogenesis. First, the number of ORF0 loci capable of encoding full-length ORF0p (~781 loci) is ~8-10 times higher than ORF1 and ORF2 (~80–100 active copies). Thus, in the setting of L1 activation, such as in SLE, it is expected that the antigenic load of ORF0p would be more robust than ORF1p and ORF2p. Second, ORF0 has two prominent splice donor sites that act in concert with splice acceptors in downstream genomic sequences, generating ORF0p-fusion proteins. This is, the N-terminus of the “host” protein would be replaced by the ORF0p N-terminal sequence, producing hybrid proteins. Based on this premise, our central hypothesis is that L1 activation in SLE leads to ORF0 dysregulation, which drives the production of anti-ORF0p antibodies and an abnormal expression of hybrid ORF0p-fusion proteins, generating neoantigens targeted in SLE. Indeed, our preliminary studies demonstrate that ORF0p is an autoantigen in SLE. The major goal of this exploratory/developmental research grant is to investigate the clinical significance of anti-ORF0p antibodies in SLE and to address the hypothesis that patients with SLE have an abnormal production of ORF0p-host fusion proteins containing lupus autoantigens.

项目摘要/摘要 全身性红斑狼疮（SLE）是一种多系统的自身免疫性疾病，其特征是持续 干扰素（IFN）信号传导和高滴度自身抗体导致免疫介导的组织损伤。异常 源自逆转录元素的核酸的积累已连接 以持续的IFN-I产生（例如SLE）为特征的疾病。特别是，非 - LTR Line1（L1）家族已显示在SLE患者中已激活。最近，发现 L1S编码的RNA结合蛋白（ORF1P）和ORF2P核酸内切酶/逆转录酶是SLE 自动抗原，支持L1元素可能在SLE发病机理中起作用的观念。该提议是 专注于对L1 5'UTR中最近发现的反义开放阅读框（ORF）的研究， 称为ORF0。 ORF0编码71个氨基酸残基的小核蛋白（ORF0P），这增加了 L1移动性。 ORF0具有几个独特的功能，这可能对潜在机制具有重要意义 L1在SLE发病机理中的作用。首先，能够编码全长ORF0P的ORF0基因座的数量（〜781 位点）比ORF1和ORF2高约8-10倍（〜80-100个活动拷贝）。在L1激活的情况下， 例如在SLE中，预计ORF0P的抗原负载将比ORF1P和ORF2P更强大。 其次，ORF0有两个杰出的剪接供体网站，它们与下游的剪接受体一起起作用 基因组序列，生成ORF0P融合蛋白。这就是“宿主”蛋白的N末端 由ORF0P N末端序列取代，产生混合蛋白。基于这个前提，我们的中央 假设是SLE中的L1激活导致ORF0失调，这驱动了抗ORF0P的产生 抗体和杂交ORF0P融合蛋白的异常表达，产生针对的新抗原 sle。确实，我们的初步研究表明，ORF0P是SLE中的自动抗原。主要目标 探索性/发展研究赠款是为了研究抗ORF0P抗体在 SLE并解决以下假设：SLE患者的ORF0P主持融合异常产生 含有狼疮自身抗原的蛋白质。