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.

项目摘要/摘要 虽然系统性红斑狼疮(SLE)的感染性病因已经被假设了超过一年 世纪之交，所有的研究都未能确定这种自身免疫性疾病的微生物原因。这导致了 寻找系统性红斑狼疮无菌炎症和I型干扰素产生的内源性驱动因素。40岁以上 人类基因组的百分之一是由成千上万的重复序列组成的，这些重复序列是从 称为转座子的遗传元件，它包含类似病毒的序列。反转录转座子是主要的 大多数哺乳动物基因组中的一类转座元件。最近几年，人们发现类似于 病毒产物，从这些基因组“寄生虫”衍生出来的核酸可以激活胞质核酸感受器。 这些发现将逆转座子的异常表达与以下疾病联系在一起 持续产生干扰素-I，如系统性红斑狼疮。特别是，对非LTR子类的有缺陷的监管 反转录转座子是一种分布较长的核素-1(LINE1或L1)，与系统性红斑狼疮有关 发病机制。为了进一步了解L1元素在系统性红斑狼疮中的潜在作用，我们重点研究了中性粒细胞 和干扰素-I，在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)。 利用有干扰素-I激活证据的系统性红斑狼疮中性粒细胞，我们初步鉴定了一种新的多态变种 ORF1.在初步研究中，我们使用该变异体编码的蛋白质(ORF1p)作为抗原，鉴定出 SLE患者首次出现L1-ORF1p抗体。这支持L1元素是 Active及其产品可刺激SLE患者的免疫反应。除了这些创新的发现，我们的 数据为L1在SLE发病机制中的作用提供了新的假说。它将注意力集中在中性粒细胞上 L1-ORF1p的一个潜在来源，表明ORF1p的多态变体(可能是错误的 被认为是“病毒衍生”的产物)可能触发针对该蛋白质的体液反应，并开启 抗ORF1p抗体可能在SLE中起致病作用。这项探索性提案的主要目标是 为了进一步洞察这些新假设和初步发现的潜在意义， 系统性红斑狼疮发病机制的背景。在目标1中，我们将使用基于捕获的L1-ORF1富集法与RNA- SEQ以确定独特的ORF1转录变异体是否在对照组和干扰素-1中差异表达 激活的SLE中性粒细胞。此外，我们将定义ORF1p变体是否优先由 系统性红斑狼疮中的抗体。在目标2中，我们将确定ORF1p抗体的流行率和临床相关性 以及它们与系统性红斑狼疮患者前瞻性观察队列中干扰素签名的关系 广泛的临床和血清学数据以及干扰素诱导的基因表达分析都是可用的。一起， 这些研究试图加强我们对无菌炎症背后的自身免疫原性途径的理解。 在系统性红斑狼疮。这项工作的最终目标是获得对疾病机制的新见解，从而为 探索新的治疗方法。