Project 3: The role of DNASE1L3 and its DNA substrate in lupus

摘要 系统性红斑狼疮(SLE)的特征是产生针对核抗原的抗体，如 作为核糖核蛋白和DNA。抗双链DNA(DsDNA)和/或染色质抗体代表 从良性到临床SLE的重要转变，并可预测红斑和组织损伤的严重程度。 系统性红斑狼疮对染色质/DNA耐受及其破坏的机制尚不清楚。我们 通过重点研究DNASE1L3来探索这些机制，DNASE1L3是一种独特的分泌DNA酶，其零突变是 与早发性家族性系统性红斑狼疮有关。我们的研究表明，微粒中的染色质来自 在体外和体内，凋亡细胞是DNASE1L3的一种特异性底物。他们还证明了 染色质和/或其他抗原暴露在微粒表面，并被 自身抗体对DNASE1L3敏感。我们假设DNASE1L3敏感的DNA/蛋白质 微粒上的复合体是人类系统性红斑狼疮重要的自身抗原，DNASE1L3可用于 将它们作为治疗的靶点。该项目的协作性质以及独特的患者样本和 我们将利用合作研究人员提供的技术来开发和测试这一假设。在AIM 1、系统性红斑狼疮患者中DNASE1L3敏感抗原抗体的发生率和临床相关性 探索过了。在目标2中，微粒上的DNASE1L3敏感抗原和针对它们的抗体将是 在分子水平上表现出来的。在目标3中，将测试DNASE1L3作为治疗剂的效用 系统性红斑狼疮动物模型。总而言之，这些研究将为我们提供对疾病起源和机制的见解 人类系统性红斑狼疮对DNA和相关抗原的致病反应，并促进新的治疗方法 他们的治疗封锁。

ABSTRACT The hallmark of systemic lupus erythematosus (SLE) is the production of antibodies to nuclear antigens such as ribonucleoproteins and DNA. Antibodies to double-stranded DNA (dsDNA) and/or chromatin represent an important transition from benign to overt clinical SLE and may predict flares and the severity of tissue damage. The mechanisms of tolerance to chromatin/DNA and of its breakdown in SLE are poorly understood. We explored these mechanisms by focusing on DNASE1L3, a unique secreted DNase whose null mutations are associated with an early-onset familial SLE. Our studies showed that chromatin in microparticles derived from apoptotic cells represented a specific substrate of DNASE1L3 in vitro and in vivo. They also demonstrated that the chromatin and/or other antigens were exposed on the surface of microparticles and recognized by autoantibodies in a DNASE1L3-sensitive manner. We hypothesize that DNASE1L3-sensitive DNA/protein complexes on microparticles are important self-antigens in human SLE, and that that DNASE1L3 can be used to target them for therapeutic purposes. The collaborative nature of the project and unique patient samples and technologies available from our co-investigators will be leveraged to develop and test this hypothesis. In Aim 1, the incidence and clinical relevance of antibodies to DNASE1L3-sensitive antigens in SLE patients will be explored. In Aim 2, DNASE1L3-sensitive antigens on microparticles and the antibodies targeting them will be characterized at the molecular level. In Aim 3, the utility of DNASE1L3 as a therapeutic agent will be tested in animal models of SLE. Collectively, these studies would provide insights into the origin and mechanisms of the pathogenic responses to DNA and associated antigens in human SLE, and facilitate novel approaches towards their therapeutic blockade.