Autoimmunity to LINE-1-encoded antigens in SLE pathogenesis

SLE 发病机制中对 LINE-1 编码抗原的自身免疫

• 批准号: 9908850
• 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: 2020
• 资助国家: 美国
• 起止时间: 2020-02-07 至 2022-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9908850
• 关键词: Address; Affinity; Antibodies; Antigens; Attention; Autoantigens; Autoimmune Diseases; Autoimmunity; C-terminal; Cells; Clinical; Consensus Sequence; DNA Transposable Elements; DNA Transposons; Data; Development; Diagnosis; Disease; Elements; Endogenous Retroviruses; Etiology; Family; Foundations; Gene Expression Profiling; Genes; Genetic Transcription; Genome; Genomic DNA; Genomics; Goals; Human; Human Genome; Immune response; Immune system; Infectious Agent; Inflammation; Interferon Type I; Interferons; Kidney; Lead; Length; Link; Long Terminal Repeats; Lupus Nephritis; Measures; Mediating; Messenger RNA; Names; Nuclear; Nucleic Acid Binding; Nucleic Acids; Open Reading Frames; Outcome Study; Parasites; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Prevalence; Prevention; Production; Proteins; RNA Recognition Motif; RNA-Binding Proteins; RNA-Directed DNA Polymerase; Regulation; Repetitive Sequence; Research Project Grants; Retroelements; Retrotransposon; Ribonucleoproteins; Role; Sequence Homology; Serological; Source; Sterility; Systemic Lupus Erythematosus; Time; Variant; Viral; Virus; Work; base; cohort; differential expression; endonuclease; genetic element; immunogenic; innovation; insight; mammalian genome; microbial; monomer; neutrophil; new therapeutic target; novel; novel diagnostics; novel therapeutics; particle; peripheral blood; prospective; response; sensor; seropositive; systemic autoimmune disease; tool; transcriptome sequencing

PROJECT SUMMARY/ABSTRACT While an infectious etiology has been hypothesized in systemic lupus erythematosus (SLE) for more than a century, all studies have failed to identify a microbial cause of this autoimmune disease. This has led to the search for endogenous drivers of sterile inflammation and type I interferon (IFN-I) production in SLE. Over 40 percent of the human genome is made up of hundreds of thousands of repetitive sequences that evolved from genetic elements called transposons, which contain virus-like sequences. Retrotransposons are the predominant class of transposable elements in most mammalian genomes. In recent years, it has been found that similar to viral products, nucleic acids derived from these genomic “parasites” can activate cytosolic nucleic acid sensors. These findings have linked dysregulated expression of retrotransposons with diseases characterized by sustained IFN-I production, such as SLE. In particular, defective regulation of a subclass of non-LTR retrotransposon, the long interspersed nuclear element-1 (LINE1 or L1), has been associated to SLE pathogenesis. To gain further insights into the potential role of L1 elements in SLE, we focused on neutrophils and IFN-I, two important players in SLE pathogenesis. L1 contains two open-reading frames (ORF1 and ORF2). Using SLE neutrophils with evidence of IFN-I activation, we initially identified a novel polymorphic variant of ORF1. Using the protein (ORF1p) encoded by this variant as an antigen in preliminary studies, we identified for the first time that patients with SLE have antibodies to L1-ORF1p. This supports the notion that L1 elements are active and their products stimulate the immune response in SLE. In addition to these innovative findings, our data provide novel hypotheses related to the role of L1 in SLE pathogenesis. It focus attention on neutrophils as a potential source of L1-ORF1p, suggests that polymorphic variants of ORF1p (which could be mistakenly recognized as “viral-derived” products) may trigger the humoral response against this protein, and opens the possibility that anti-ORF1p antibodies may be pathogenic in SLE. The major goal of this exploratory proposal is to gain further insights into the potential significance of these novel hypotheses and preliminary findings in the context of SLE pathogenesis. In Aim 1, we will use capture-based enrichment of L1-ORF1 combined with RNA- Seq to determine whether unique ORF1 transcriptional variants are differentially expressed in control and IFN- activated SLE neutrophils. In addition, we will define whether ORF1p variants are preferentially recognized by antibodies in SLE. In Aim 2, we will determine the prevalence and clinical associations of antibodies to ORF1p and their relationship to the IFN-signature in a prospective observational cohort of patients with SLE, for which extensive clinical and serologic data is available, as well as IFN-induced gene expression analysis. Together, these studies seek to enhance our understanding of self-immunogenic pathways underlying sterile inflammation in SLE. The final goal of this work is to gain new insights into disease mechanisms, thus laying the foundation to explore novel therapies.

项目概要/摘要 虽然感染性病因已被用于治疗系统性红斑狼疮 (SLE) 超过一个世纪 本世纪以来，所有研究都未能确定这种自身免疫性疾病的微生物原因。 寻找 SLE 患者无菌炎症和 I 型干扰素 (IFN-I) 产生的内源性驱动因素。 人类基因组的 % 由数十万个重复序列组成，这些序列是从 称为转座子的遗传元件，其中包含病毒样序列，是主要的。 近年来，人们发现大多数哺乳动物基因组中存在一类转座元件。 病毒产物、源自这些基因组“寄生虫”的核酸可以激活胞质核酸传感器。 这些发现将逆转录转座子的表达失调与以下疾病联系起来： 持续的 IFN-I 产生，例如 SLE，特别是非 LTR 亚类的调节缺陷。 逆转录转座子，即长散布的核元件 1（LINE1 或 L1），与 SLE 相关 为了进一步了解 L1 元素在 SLE 中的潜在作用，我们重点关注中性粒细胞。 和 IFN-I，SLE 发病机制中的两个重要角色，L1 包含两个开放阅读框（ORF1 和 ORF2）。 使用具有 IFN-I 激活证据的 SLE 中性粒细胞，我们最初鉴定了一种新的多态性变体 在初步研究中，我们使用该变体编码的蛋白质（ORF1p）作为抗原，鉴定出 SLE 患者首次出现 L1-ORF1p 抗体，这支持了 L1 元件的观点。 Active 及其产品可刺激 SLE 的免疫反应。 数据提供了与 L1 在 SLE 发病机制中的作用相关的新假设，它将注意力集中在中性粒细胞上。 L1-ORF1p 的潜在来源，表明 ORF1p 的多态性变体（可能被错误地 被认为是“病毒衍生的”产品）可能会引发针对这种蛋白质的体液反应，并打开 抗 ORF1p 抗体可能在 SLE 中致病的可能性 该探索性提案的主要目标是。 进一步了解这些新假设和初步发现的潜在意义 在目标 1 中，我们将结合 RNA-基于捕获的 L1-ORF1 富集。 测序以确定独特的 ORF1 转录变体在对照和 IFN- 中是否差异表达 此外，我们将定义 ORF1p 变体是否优先被识别。 在目标 2 中，我们将确定 ORF1p 抗体的流行率和临床关联。 及其与系统性红斑狼疮患者前瞻性观察队列中干扰素特征的关系，其中 可以获得广泛的临床和血清学数据，以及 IFN 诱导的基因表达分析。 这些研究旨在增强我们对无菌炎症背后的自身免疫原性途径的理解 这项工作的最终目标是获得对疾病机制的新见解，从而奠定基础。 探索新疗法。