Maternal Autoantibodies: Pathogenesis of Neonatal Lupus

母体自身抗体：新生儿狼疮的发病机制

• 批准号: 8776576
• 负责人: Jill P Buyon
• 金额: $ 20.52万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-12-05 至 2015-03-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8776576
• 关键词: Accounting; Address; Affect; Animal Model; Antigen-Antibody Complex; Apoptosis; Apoptotic; Autoantibodies; Autoantigens; Autoimmune Process; Autoimmunity; Autologous; Automobile Driving; Autopsy; Binding; Biological Assay; Blood specimen; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cells; Chickens; Cicatrix; Clinical; Coculture Techniques; Collagen; Collagen Type I; Complex; Cyclic AMP; Development; Disease; Distal; Endocardium; Enzyme-Linked Immunosorbent Assay; Equilibrium; Erythropoietin; Evaluation; Fc Receptor; Fetus; Fibroblasts; Fibrosis; Frequencies; Functional disorder; Funding; Gap Junctions; Gene Proteins; Genes; Genetic; Genetic Polymorphism; Genotype; Healed; Heart; Heart Block; Histologic; Human; Hypoxia; Hypoxia Inducible Factor; Immune system; Immunity; Immunoblotting; Immunoglobulin G; In Situ Nick-End Labeling; In Vitro; Inflammation; Inflammation Mediators; Inflammatory; Injury; Intervention; Investigation; Knock-out; Laboratories; Life; Ligands; Ligation; Link; Location; Macrophage Activation; Maps; Measurement; Mechanics; Mediating; Mediator of activation protein; Modeling; Molecular Profiling; Monozygotic Twinning; Monozygotic twins; Mothers; Motion; Mus; Myocardium; Myofibroblast; Neonatal; Neonatal lupus erythematosus; Nodal; Organ; Oxygen; Pathogenesis; Pathogenicity; Pathologic; Pathway interactions; Peptides; Phagocytes; Phagocytosis; Phenotype; Physiological; Plasminogen Inactivators; Predisposition; Pregnancy; Prevention; Process; Property; Protein Kinase; Proteins; Proxy; RNA; Receptor Signaling; Relative (related person); Research; Resistance; Rheumatism; Ribonucleoproteins; Risk; Role; SS-A antigen; Serum; Siblings; Signal Transduction; Signaling Molecule; Sinus; Specificity; Specimen; Stimulus; Stress; System; TLR7 gene; TNF gene; Time; Tissues; Toll-Like Receptor Pathway; Toll-like receptors; Translational Research; Umbilical Cord Blood; Up-Regulation; Work; Wound Healing; annexin A5; arm; cytokine; directed attention; fetal; healing; human MADH3 protein; hypoxia inducible factor 1; in utero; in vivo; inhibitor/antagonist; mRNA Expression; mTOR protein; macrophage; macrophage product; neonate; novel; protein profiling; receptor; research study; response; treatment strategy; uptake

DESCRIPTION (provided by applicant): Identification of isolated congenital heart block (CHB) in a fetus predicts with near certainty that the mother, who may have a rheumatic disease or be asymptomatic, will have autoantibodies (Ab) to SSA/Ro ribonucleoproteins. CHB, a pathologic readout of passively acquired autoimmunity, provides an exceptional opportunity to examine the effector arm of immunity and define the mechanism whereby an Ab mediates fibrosis, which is particularly aberrant in fetal wounding. The study of CHB exemplifies not only translational research, which draws upon clinical clues and explores them in the laboratory, but "integrational" research which attempts to fit key clinical and basic observations together. In the previous funding periods we leveraged several rare fetal/neonatal autopsy specimens to interrogate clues to pathogenesis. Exaggerated apoptosis, macrophage/myfibroblast crosstalk, TGF2 expression, and extensive fibrosis in the conduction system (and, in some, the surrounding myocardium) of CHB-hearts, provided in vivo support for parallel in vitro investigation. Positing apoptosis as the initial link between Ab and tissue injury led to the first-time observation that healthy cardiocytes are capable of phagocytosing apoptotic cardiocytes, and that anti-Ro/La Abs inhibit this function. That this perturbation of physiologic efferocytosis diverts uptake to professional Fc3R-bearing phagocytes fits well with ongoing experiments demonstrating macrophage secretion of pro-inflammatory and fibrosing cytokines when coincubated with apoptotic cardiocytes bound by anti-Ro/La Ab. The macrophage engagement of Toll-like receptors (TLR) via binding to the RNA moiety of the target autoantigen was suggested by recent experiments. The potential for relative oxygen insult during pregnancy, and the need to explain CHB- discordance in monozygotic twins, directed attention to hypoxia as an amplification factor on the distal fibrosing component. Footprints of hypoxic injury comprised expression of hypoxia-inducible factor (HIF)-11 in affected hearts and increased erythropoietin levels in several CHB-cord bloods. In Aim 1, the specificity and mechanism of anti-Ro/La Ab in inhibiting efferocytosis by autologous human fetal cardiocytes will be evaluated. It is hypothesized that binding of anti-Ro/La Ab to apoptotic cardiocytes not only inhibits clearance but, by opsonizing these cells, provides the immune complex for subsequent uptake by professional phagocytes. In Aim 2, the nexus of Fc3 receptor (Fc3R) and TLR signaling following macrophage uptake of opsonized apoptotic cardiocytes will be addressed with regard to release of mediators that promote inflammation and fibrosis. The hypothesis driving this aim is that opsonization of apoptotic cardiocytes induces macrophage uptake by an Fc3R-dependent pathway and activation via TLR ligation, which set in motion the final step to irreversible scar. The experiments of Aim 3 address the mechanism by which the inflammatory cascade initiated by anti-Ro/La Abs induces a persistent fibrosing phenotype in the cardiac fibroblast. The hypothesis is that macrophage products prime the fibroblast toward scar, which is further abetted by an in utero stress such as hypoxia. Fetuses of mothers who are otherwise healthy or who suffer from a rheumatic disease but have autoantibodies to SSA/Ro are at risk for having permanent heart damage, which requires permanent pacing at some point in life or can be fatal. Understanding the mechanism by which these autoantibodies cause cardiac scarring is critical to the development of strategies for treatment or prevention of this condition, known as congenital heart block.

描述（由申请方提供）：在胎儿中鉴定出孤立性先天性心脏传导阻滞（CHB），几乎可以肯定地预测母亲（可能患有风湿性疾病或无症状）将具有抗SSA/Ro核糖核蛋白的自身抗体（Ab）。CHB是被动获得性自身免疫的病理学读数，它提供了一个特殊的机会来检查免疫的效应臂，并确定Ab介导纤维化的机制，这在胎儿创伤中特别异常。CHB的研究不仅体现了转化研究，即利用临床线索并在实验室中进行探索，而且还体现了“整合”研究，即试图将关键的临床和基础观察结合在一起。在以前的资助期间，我们利用几个罕见的胎儿/新生儿尸检标本来询问发病机制的线索。CHB心脏传导系统（以及部分周围心肌）的细胞凋亡、巨噬细胞/肌成纤维细胞串扰、TGF-2表达和广泛纤维化，为平行的体外研究提供了体内支持。假定细胞凋亡作为Ab和组织损伤之间的最初联系，导致首次观察到健康的心脏细胞能够吞噬凋亡的心脏细胞，并且抗Ro/La Ab抑制该功能。这种生理性巨噬细胞的扰动将摄取转移到专业的携带Fc 3R的吞噬细胞，这与正在进行的实验非常吻合，该实验表明，当与抗Ro/La Ab结合的凋亡心肌细胞共孵育时，巨噬细胞分泌促炎性和纤维化细胞因子。最近的实验表明，巨噬细胞通过与靶自身抗原的RNA部分结合来参与Toll样受体（TLR）。潜在的相对氧损伤在怀孕期间，并需要解释CHB-单卵双胞胎的不一致性，引起注意缺氧作为一个放大因素的远端纤维化的组成部分。缺氧损伤的足迹包括缺氧诱导因子（HIF）-11在受累心脏中的表达和几种CHB-脐带血中促红细胞生成素水平的增加。在目的1中，将评价抗Ro/La Ab抑制自体人胎心肌细胞红细胞增多症的特异性和机制。据推测，抗Ro/La Ab与凋亡心肌细胞的结合不仅抑制清除，而且通过调理这些细胞，提供免疫复合物供专职吞噬细胞随后摄取。在目标2中，将针对促进炎症和纤维化的介质的释放，阐述在巨噬细胞摄取调理的凋亡心脏细胞后Fc 3受体（Fc 3R）和TLR信号传导的关系。驱动这一目标的假设是凋亡心肌细胞的调理作用通过Fc 3R依赖性途径诱导巨噬细胞摄取，并通过TLR连接激活，这启动了不可逆瘢痕的最后一步。目的3的实验阐明了由抗Ro/La Ab引发的炎症级联反应在心脏成纤维细胞中诱导持续纤维化表型的机制。假设是巨噬细胞产物使成纤维细胞向瘢痕生长，这进一步受到子宫内应激如缺氧的刺激。母亲健康或患有风湿性疾病但具有SSA/Ro自身抗体的胎儿有永久性心脏损伤的风险，这需要在生命的某个时刻永久起搏或可能致命。了解这些自身抗体导致心脏瘢痕形成的机制对于开发治疗或预防这种称为先天性心脏传导阻滞的疾病的策略至关重要。