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

摘要 系统性红斑狼疮（SLE）的标志是产生针对核抗原的抗体， 核糖核蛋白和DNA。针对双链DNA（dsDNA）和/或染色质的抗体代表了针对双链DNA（dsDNA）和染色质的抗体。 从良性到显性临床SLE的重要转变，并可预测复发和组织损伤的严重程度。 对染色质/DNA的耐受机制及其在SLE中的破坏机制知之甚少。我们 通过关注DNASE 1 L3来探索这些机制，DNASE 1 L3是一种独特的分泌型DNA酶， 与早发性家族性SLE相关我们的研究表明，来源于 凋亡细胞在体外和体内代表了DNASE 1 L3的特异性底物。他们还证明， 染色质和/或其它抗原暴露在微粒的表面上， 以DNASE 1 L3敏感的方式检测自身抗体。我们假设DNASE 1 L3敏感的DNA/蛋白质 微粒上的复合物是人类SLE中重要的自身抗原，并且可以使用DNASE 1 L3 以达到治疗目的该项目的协作性质和独特的患者样本， 将利用我们的合作研究者提供的技术来发展和检验这一假设。在Aim中 1、SLE患者中抗DNASE 1 L3敏感抗原抗体的发生率和临床相关性， 探讨了在目标2中，微粒上的DNASE 1 L3敏感性抗原和靶向它们的抗体将被 在分子水平上表征。在目的3中，将在以下中测试DNASE 1 L3作为治疗剂的效用： SLE动物模型。总的来说，这些研究将提供对起源和机制的见解， 对DNA和相关抗原的致病反应，并促进新的方法， 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.