FcRIIA, Platelet Activity, and Vasculopathy in Systemic Lupus Erythematosus

系统性红斑狼疮中的 FcRIIA、血小板活性和血管病变

• 批准号: 9234729
• 负责人: Jeffrey S Berger
• 金额: $ 22.37万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-15 至 2019-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9234729
• 关键词: Accounting; Address; Adrenal Cortex Hormones; Affect; Affinity; African American; Age; Agonist; Amino Acid Substitution; Antigen-Antibody Complex; Antiphospholipid Antibodies; Antiplatelet Drugs; Asians; Atherosclerosis; Autoimmune Diseases; Biological Markers; Blocking Antibodies; Blood Platelets; Blood Vessels; CD40 Ligand; Calcium; Cardiovascular Diseases; Carotid Arteries; Carotid Artery Plaques; Cells; Cessation of life; Clinical; Clinical Research; Code; Complex; Coronary artery; Data; Dependency; Diabetes Mellitus; Diagnostic; Disease; Dyslipidemias; Electron Beam Tomography; Endothelial Cells; Ethnic Origin; Exhibits; Genes; Genetic; Genetic Transcription; Genotype; Goals; Heart Rate; Heparin; Heterogeneity; Heterozygote; Hispanics; Homozygote; Hypertension; Immunoglobulin G; Immunologic Receptors; Individual; Inflammation; Inflammatory; Influenza; Leukocytes; Ligand Binding Domain; Ligands; Ligation; Light; Lupus; Major Histocompatibility Complex; Measurement; Measures; Mediating; Mediator of activation protein; Molecular; Myocardial Infarction; Organ; P-Selectin; PAC1 phosphatase; Pathogenesis; Pathologic; Patients; Pharmaceutical Preparations; Phenotype; Platelet Activation; Play; Preventive; Process; Proxy; RNA; Race; Risk; Role; Serological; Signal Pathway; Signal Transduction; Smoking; Subgroup; Systemic Lupus Erythematosus; TNFRSF5 gene; Testing; Therapeutic; Thrombocytopenia; Thrombosis; Time; Toll-like receptors; Transcript; Translations; Untranslated RNA; Variant; Vascular Diseases; Woman; activity marker; aged; atherothrombosis; base; cardiovascular risk factor; cohort; extracellular; gain of function; high risk; illness length; immune activation; insight; intimal medial thickening; light transmission; macrophage; men; monocyte; novel marker; peripheral blood; premature; premature atherosclerosis; receptor; receptor expression; response; sex; therapeutic target; transcriptome; transcriptome sequencing; transcriptomics

ABSTRACT Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by heterogeneity of presentation, an undulating course, and a remarkably elevated risk for premature cardiovascular disease. Platelets have been understudied as a relevant contributor to premature atherosclerosis in SLE. Yet these cells, which contain transcripts and the necessary molecular machinery to conduct translation, are intercellular regulators of inflammation and immune activation and play a key role in atherothrombosis. Platelets express low affinity type 2 receptor (FcγRIIA) whose ligand is the Fc portion of IgG. A single amino acid substitution, H131R, in the extracellular ligand binding domain increases the affinity for IgG and may account for individual variation in platelet activation, specifically gain of function. Leveraging a well-characterized SLE cohort, we identified a significant enrichment of carotid plaque in patients carrying at least one copy of the variant compared to those homozygotic for the ancestral gene. In a second SLE cohort, a significant increase in monocyte-platelet aggregates (MPA) in patients carrying the variant versus ancestral gene was observed. Although not yet assessed for genotype, SLE platelets exhibited a hyperreactive phenotype relative to healthy donors. Accordingly, it is hypothesized that platelet activity measurements and platelet-derived coding and non-coding RNA are significantly influenced by FcγRIIA genotype. Two aims provide complementary studies to evaluate the underlying mechanism of increased platelet activity in SLE. In Specific Aim 1 the relationship between SLE platelet phenotype and transcriptome in the context of FcγRIIA genotype will be investigated. To test the influence of FcγRIIA genotype on platelets, a multidimensional panel of platelet activity markers representing different pathophysiological mechanisms will be measured, including: light transmission aggregometry (LTA); leukocyte- and monocyte-platelet aggregates; reticulated platelets; platelet receptor expression of PAC-1, CD40 ligand, P-selectin; platelet size; and the platelet transcriptome. Readouts will be assessed and compared in three groups of SLE subjects: H/H homozygotes, R/H heterozygotes, and R/R homozygotes. In Specific Aim 2 the goal is to molecularly assess platelet reactivity dependent on FcRIIA ligation and the impact of genotype on the phenotype of the vascular targets, endothelial cells (ECs) and macrophages. In contrast to Specific Aim 1, the approach utilizes platelets from healthy controls (H/H, R/H, and RR) since platelets from SLE patients may be intrinsically coated with immune complexes (ICs) accounting for baseline reactivity. Co-treatment of platelets with anti-CD9 will serve as a proxy of ICs and FcγRIIA dependency approached using blocking antibodies. ECs and macrophages co-cultured with anti-CD9 platelets will be assessed for both pro-inflammatory and protective signaling cascades. Identification of a novel biomarker to gauge response to therapy, and/or to be used to identify patients at increased risk for premature cardiovascular disease and likely to benefit from anti-platelet agents, would be an advance.

抽象的 系统性红斑狼疮（SLE）是一种复杂的自身免疫性疾病，其特征为异质性 表现、病程起伏不定，以及过早罹患心血管疾病的风险惊人地升高。 血小板作为 SLE 过早动脉粥样硬化的相关因素尚未得到充分研究。 细胞包含转录本和进行翻译所需的分子机制，是细胞间细胞 炎症和免疫激活的调节因子，并在动脉粥样硬化血栓形成中发挥关键作用。 低亲和力 2 型受体 (FcγRIIA)，其配体是 IgG 的 Fc 部分，单个氨基酸取代， H131R，在细胞外配体结合域中增加了对 IgG 的亲和力，并且可能解释个体 血小板活化的变化，特别是功能的获得，我们利用一个充分表征的 SLE 队列。 在携带至少一个变异拷贝的患者中发现颈动脉斑块显着富集 与那些祖先基因纯合的人相比，在第二个 SLE 队列中，显着增加。 观察到携带变异基因与祖先基因的患者的单核细胞-血小板聚集体（MPA）。 尽管尚未评估基因型，但 SLE 血小板相对于健康人表现出高反应性表型 因此，人们对血小板活性测量和血小板衍生编码和研究充满兴趣。 非编码 RNA 受 FcγRIIA 基因型的显着影响有两个目标提供了互补的研究。 评估 SLE 中血小板活性增加的潜在机制。 FcγRIIA 基因型背景下 SLE 血小板表型和转录组之间的关系将是 研究了 FcγRIIA 基因型对血小板（多维血小板组）的影响。 将测量代表不同病理生理机制的活动标记，包括： 透射聚集法（LTA）；白细胞和单核细胞血小板聚集体； PAC-1、CD40 配体、P-选择素的受体表达；血小板大小和血小板转录组读数。 将在三组 SLE 受试者中进行评估和比较：H/H 纯合子、R/H 杂合子和 在特定目标 2 中，R/R 纯合子的目标是根据血小板反应性进行分子评估。 Fc-RIIA 连接以及基因型对血管靶标、内皮细胞表型的影响 (EC) 和巨噬细胞与特定目标 1 不同，该方法利用来自健康对照的血小板。 （H/H、R/H 和 RR），因为 SLE 患者的血小板可能本质上涂有免疫复合物 (IC) 考虑血小板与抗 CD9 的基线反应性将作为 IC 和的代表。 使用封闭抗体和巨噬细胞与抗 CD9 共培养来接近 FcγRIIA 依赖性。 将评估血小板的促炎性和保护性信号级联，鉴定一种新型的。 生物标志物来衡量对治疗的反应，和/或用于识别早产风险增加的患者 心血管疾病并可能受益于抗血小板药物，将是一个进步。