LINE1-ORF0 in SLE pathogenesis

SLE 发病机制中的 LINE1-ORF0

基本信息

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
项目类别：
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&apos Splice Site 5&apos 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

项目摘要

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.

项目概要/摘要系统性红斑狼疮（SLE）是一种多系统自身免疫性疾病，其特征是持续性的干扰素 (IFN) 信号传导和高滴度自身抗体导致免疫介导的组织损伤。源自逆转录转座子（一类转座元件）的核酸积累与以持续产生IFN-I为特征的疾病，例如SLE，特别是非逆转录转座子。最近发现，LTR LINE1 (L1) 家族在 SLE 患者中被激活。 L1 编码的 RNA 结合蛋白 (ORF1p) 和 ORF2p 核酸内切酶/逆转录酶是 SLE 自身抗原，支持 L1 元件可能在 SLE 发病机制中发挥作用的观点。重点研究最近在 L1 5'UTR 中发现的反义开放阅读框 (ORF)， ORF0 编码一个由 71 个氨基酸残基组成的小核蛋白 (ORF0p)，该蛋白会增加 L1 迁移率有几个独特的特征，这可能对潜在的机制产生重要影响。 L1 在 SLE 发病机制中的作用首先，能够编码全长 ORF0p 的 ORF0 位点的数量（~781）。位点）比 ORF1 和 ORF2（约 80-100 个活性拷贝）高约 8-10 倍，因此，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。其次，ORF0 有两个突出的剪接供体位点，它们与下游的剪接受体协同作用基因组序列，生成 ORF0p 融合蛋白，即“宿主”蛋白的 N 末端。被 ORF0p N 端序列替换，产生杂合蛋白。基于这个前提，我们的中心。假设 SLE 中 L1 激活导致 ORF0 失调，从而驱动抗 ORF0p 的产生抗体和杂合 ORF0p 融合蛋白的异常表达，产生靶向的新抗原事实上，我们的初步研究表明 ORF0p 是 SLE 的自身抗原。探索性/发展性研究资助旨在研究抗 ORF0p 抗体在 SLE 并解决 SLE 患者 ORF0p-宿主融合异常产生的假设含有狼疮自身抗原的蛋白质。