Mechanisms for Human TLR8 induced pregnancy loss in a mouse model of SLE

人 TLR8 诱导 SLE 小鼠模型妊娠失败的机制

基本信息

批准号：
10434117
负责人：
Anne Davidson
金额：
$ 25.44万
依托单位：
FEINSTEIN INSTITUTE FOR MEDICAL RESEARCH
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-06-18 至 2024-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10434117
关键词：
Address Amino Acids Antibodies Antigen-Antibody Complex Antiphospholipid Antibodies Attenuated Autoantibodies Autoimmune Diseases Autoimmunity B-Lymphocyte Subsets B-Lymphocytes Bacterial Artificial Chromosomes Binding Binding Sites Blood Vessels Cell Line Cell Lineage Cells Characteristics Development Dose Exposure to Female Fetal Death Fetal Resorption Gene Expression Genetic Polymorphism Genetic study Goals Human IL8 gene Immune Immunologic Receptors In Vitro Inflammation Inflammatory Injury Innate Immune System Interferon Type I Lead Ligand Binding Ligands Lupus Lymphocyte Mediating Memory B-Lymphocyte Messenger RNA MicroRNAs Modeling Morphology Mus Myelogenous Myeloid Cells Nucleic Acids Pathogenicity Pathway interactions Patients Pattern Phenotype Phospholipids Physiological Placenta Plasma Cells Pregnancy Pregnancy Outcome Pregnancy loss Production Purines Quality of life RNA RNA Binding Ribonucleases Role SLEB1 gene Susceptibility Gene Syndrome Systemic Lupus Erythematosus TLR7 gene TLR8 gene Testing Tissues Toll-like receptors Transgenes Transgenic Mice Uridine Woman antagonist cell injury cytokine effective therapy experimental study exposed human population fetal fetal loss fetus cell improved outcome in vivo inflammatory milieu lupus prone mice macrophage monocyte mortality mouse model neutrophil novel novel strategies pathogenic autoantibodies placental morphology prevent promoter receptor recruit response sensor therapeutic target transgene expression trophoblast

项目摘要

Systemic lupus erythematosus (SLE) is a multisystem, autoimmune disease that causes a significant decrease in quality of life and early mortality. Genetic studies have identified activation of the innate immune system, with excess production of Type I interferons as a major causative pathway. RNA-sensing Toll-like receptors are crucial protective receptors of the innate immune system but are also implicated in autoimmunity because they can recognize nucleic acids released from damaged cells and within nucleic acid containing immune complexes. Functional polymorphisms of the endosomal RNA-recognizing innate receptors TLR7 and TLR8 predispose to SLE and excess mouse TLR7 and human TLR8 accelerate lupus in mouse models. Human TLR8 differs in its function from TLR7 because it recognizes different ligands and is expressed on different immune cell subsets. TLR8 is not an RNA sensor in mice because of a 5 amino acid deletion that attenuates its RNA-binding site. We therefore bred a human TLR8 BAC transgene (huTLR8) into mice in which a mild lupus phenotype is conferred by the susceptibility locus Sle1. Expression of the transgene is physiologically regulated such that huTLR8 is expressed at high levels in myeloid DCs and monocytes but at 50-100-fold lower levels in lymphocytes. We found that huTLR8 induces an anti- phospholipid like syndrome in Sle1 mice that leads to spontaneous placental inflammation, fetal resorptions and late-term pregnancy loss in up to 60% of female dams. In this proposal we will test the mechanism for huTLR8 mediated pregnancy loss by addressing the role of huTLR8 as a sensor of RNA in placental trophoblasts and immune cells. In Aim 1 we will examine the role of autoantibodies in placental injury in mice with or without huTLR8 expression and determine whether huTLR8 expression in B cells results in the production of autoantibodies with enhanced pathogenicity. In Aim 2 we will determine the timing and characteristics of placental injury, the contribution of huTLR8 in maternal vs. fetal cells to injury and whether placental trophoblasts activated by anti-phospholipid antibodies release huTLR8 ligands that enhance local inflammation. In Aim 3 we will determine whether myeloid cells from huTLR8tg mice are intrinsically more pro-inflammatory than those of their wild-type counterparts and therefore amplify the effector response to antibody mediated placental injury. These experiments should allow us to distinguish the role of huTLR8 in maternal cells, trophoblasts and immune cell subsets in the induction of placental damage that leads to pregnancy loss. Our studies will inform us whether specific huTLR8 antagonists or antagonists of huTLR8 ligands should be tested for their ability to prevent or treat placental injury.

系统性红斑狼疮 (SLE) 是一种多系统自身免疫性疾病，可导致生活质量和早期死亡率显着下降。遗传学研究已确定激活先天免疫系统，其中 I 型干扰素的过量产生是主要因素因果途径。 RNA 感应 Toll 样受体是先天性的重要保护性受体免疫系统，但也与自身免疫有关，因为它们可以识别核酸从受损细胞和含有免疫复合物的核酸中释放。功能性内体 RNA 识别先天受体 TLR7 和 TLR8 的多态性易感在小鼠模型中，SLE 和过量的小鼠 TLR7 和人 TLR8 会加速狼疮的发生。人类 TLR8 的功能与 TLR7 不同，因为它识别不同的配体并表达针对不同的免疫细胞亚群。 TLR8 不是小鼠体内的 RNA 传感器，因为 5 个氨基酸的缺失削弱了其作用 RNA 结合位点。因此，我们将人类 TLR8 BAC 转基因 (huTLR8) 培育到小鼠体内，其中轻度狼疮表型由易感基因座 Sle1 赋予。转基因的表达受到生理调节，使得 huTLR8 在骨髓 DC 中高水平表达，并且单核细胞中的水平低 50-100 倍，淋巴细胞中的水平低 50-100 倍。我们发现 huTLR8 诱导抗 Sle1 小鼠的磷脂样综合征导致自发性胎盘炎症、胎儿高达 60% 的雌性母猪出现吸收和晚期妊娠流产。在本提案中，我们将通过解决 huTLR8 作为胎盘滋养层和免疫细胞中的 RNA 传感器。在目标 1 中，我们将检查自身抗体在患有以下疾病的小鼠胎盘损伤中的作用：没有 huTLR8 表达，并确定 B 细胞中 huTLR8 表达是否会导致产生具有增强致病性的自身抗体。在目标 2 中，我们将确定时间胎盘损伤的特征、母体细胞和胎儿细胞中 huTLR8 对胎盘损伤的贡献损伤以及抗磷脂抗体激活的胎盘滋养层细胞是否释放 huTLR8 配体增强局部炎症。在目标 3 中，我们将确定是否有骨髓细胞 huTLR8tg 小鼠的细胞本质上比野生型小鼠的细胞更具促炎性对应物，因此放大了对抗体介导的胎盘损伤的效应反应。这些实验应该使我们能够区分 huTLR8 在母体细胞中的作用，滋养层和免疫细胞亚群在诱导胎盘损伤中的作用，从而导致妊娠损失。我们的研究将告诉我们是否有特定的 huTLR8 拮抗剂或 huTLR8 拮抗剂应测试 huTLR8 配体预防或治疗胎盘损伤的能力。