本课题组应用临床和动物学实验，首次发现AT1受体活化自身抗体（AT1-AA ）在子痫前期中的关键致病作用。最近几年此发现已经被国内外多个实验室证实。 但AT1-AA如何在子痫前期病人中产生的机制尚不明确。 我们前期研究发现，翻译后修饰（PTM）酶TG2和新型TNF超家族成员LIGHT在子痫前期患者血清中的表达水平显著增高，且外源性LIGHT可增加孕鼠血清中TG2活性，TG2可使AT1R发生PTM和促进AT1-AA持续产生。由此我们推测：LIGHT引起的TG2活性上调及TG2介导的AT1R蛋白质的PTM诱发了新的自身抗原和AT1-AA持续产生。本项目拟进行TG2是否是诱导AT1-AA产生的关键机制和人类转化医学的研究,明确AT1-AA、LIGHT和TG2是否是子痫前期早期诊断的靶点。期望通过本研究，进一步明确自身免疫机制在子痫前期发病中的分子调控机制，为临床早期预测及治疗提供新的策略。

This is a competitive renewal application that seeks funding to continue our current research to determine several newly identified pathogenic factors in the etiology of preeclampsia (PE), a serious hypertensive disease of pregnancy. The goal of proposed research is the development of pre-symptomatic diagnostic tests for early detection and novel approaches to treat PE. Although PE remains a leading cause of maternal and neonatal morbility and mortality, we lack effective mechanism-based therapies due to poorly understood pathogenesis of PE. As an important mission of NSFC is to develop highly innovative treatments for this disease, the goal of the proposed work should be of high priority. Research proposed here is based on our previous and recent unexpected discoveries that identified multiple pathogenic factors in PE including AT1R agonistic autoantibodies (termed AT1-AAs), tissue transglutaminase (TG2), an enzyme catalyzing posttranslational modification (PTM) by covalent crosslinking, and LIGHT, a TNF-a superfamily member. Follow-up studies revealed that LIGHT infusion induced TG2 activity and AT1-AA production in pregnant mice, while inhibition of TG2 activation or knockdown of TG2 reduced both circulating TG2 activity and AT1-AA production. These finding led us to further discover that TG2-mediated PTM of AT1R prevented its proteasome degradation and increased its cellular expression. Thus, multiple lines of evidence including human, mice and molecular studies raise a novel but compelling hypothesis that TG2-mediated PTＭ of AT1R triggers neo-antigen production, AT1-AA production and disease development. The project has interrelated goals to translate our findings into innovative therapeutics for PE by providing new insight into disease pathogenesis. In AIM I, we propose to use both pharmacological and genetic approaches to determine the pathogenic role of elevated TG2 in PE including AT1-AA production by using multiple well characterized mouse models of PE. These studies will provide strong evidence for a general pathogenic role of TG2 in PE and establish the foundation for appropriate clinical trials in humans with PE. In AIM II, we will explore several different approaches including genetic, pharmacological, biochemical coupled with mass spectrometry analysis to test a novel but compelling hypothesis that TG2 functions downstream of LIGHT and other cytokines inducing extracellular PTM of AT1R, then forming a neoantigen that subsequently triggers AT1-AA production in mouse. We will further validate the specific PTM of AT1R in the placentas from patients with PE. These studies are expected to resolve a long-term puzzle concerning the immunological basis of AT1-AA production in PE and reveal novel therapeutic targets. In AIM III, we propose to conduct longitudinal human studies to test our hypothesis regarding the temporal relationships among increased proinflammatory cytokines, elevated plasma TG2 activities, AT1-AA and clinical features of PE through pregnancy. This study is highly translational to setup a strong foundation for timely detection and removal or inhibition of these pathogenic molecules in preeclamptic women. Overall, the proposed preclinical animal studies and translational human studies are expected to provide significant new insight for pathogenesis of PE and reveal early pathogenic biomarkers and important therapeutic targets in the personalized medical management of PE.