EGFR核心岩藻糖基化调节EMT-MET对肾间质纤维化的作用

Renal interstitial fibrosis is an inevitable consequence of many chronic kidney diseases. Epithelial-mesenchymal transition (EMT) in renal tubular epithelial cells and the reverse process, mesenchymal-epithelial transition (MET) in renal interstitial cells are often associated with renal interstitial fibrosis. Among the diverse causative factors, transforming growth factor-beta 1(TGF-β1) and Epidermal growth factor (EGF)are cytokines which can strongly induce EMT. TGF-βR and EGFR are both glycoproteins.They are modified by core fucosylation and then have the ability of binding their ligands TGF-β and EGF in EMT-inducing signaling pathways. Our previous study showed that core fucosylation has profound effects on the activation of EMT process in cultured human renal proximal tubular epithelial cells in EMT vitro model and fibrosis process in UUO rat kidney in EMT vivo model. However, it is not clear how does EGFR balace the role of the EMT-MET regulation during the process of the renal interstitial fibrosis. This study will have a profound research on the basis of the previous study, in the combined analyses of in vitro and in vivo studies, to further clarify the mechanism of action of EGF-receptor core fucosylation in the process of EMT-MET regulation in kidney, provide theoretical and experimental basis for the pathogenesis of renal interstitial fibrosis, and a novel and effective strategy of targeting the EGF receptor core fucosylation for treatment of fibrotic renal disorders.

肾间质纤维化是慢性肾脏疾病不断进展的的共同病理改变，其发生与肾小管上皮细胞EMT转化及肾间质细胞MET逆转的实时调节密切关联。研究表明TGF-β与EGF是最强的促进EMT发生发展的细胞因子。TGF-βR与EGFR均属于糖蛋白， 它们必须经过核心岩藻糖基化修饰后才具备和其配体TGF-β与EGF结合的功能，激活下游"致EMT通路"。项目组前期工作发现TGF-βR核心岩藻糖基化修饰在HK2细胞建立的 EMT体外模型与单侧输尿管梗阻大鼠肾脏的EMT体内模型中发挥了关键的作用，但EGFR在肾间质纤维化发病过程中对EMT-MET的平衡调控作用目前尚未明了。本项目拟在该工作基础上深入研究，结合体内与体外实验研究分析结果，检测EGFR糖基化修饰在肾脏EMT-MET调控中的作用机制，从而为肾间质纤维化的发病机制提供理论和实验依据，并为开拓以EGFR核心岩藻糖基化为靶点治疗慢性肾脏病这一全新途径奠定实验基础。

在本基金的资助下，我们完成预期研究内容。首先，本项目发明了一种全新输尿管梗阻后再通(RUUO)动物模型构建方法，采用聚乙烯吡咯烷酮(PVP)涂层显微血管夹造模，克服了之前普通血管夹引起的黏连和梗阻再通失败的缺点，极大提高了RUUO模型造模成功率。其次，本课题证实大鼠RUUO介导了肾脏EMT-MET的发生，为肾间质纤维化的机制提供了新的启示。最后，本研究发现了在RUUO基础上抑制EGFR核心岩藻糖基化较之单纯RUUO能够更有效的减轻肾间质纤维化损害，为临床上众多预后性不良的肾后性AKI患者提供了新的治疗思路及手段。本项目在分子、细胞、动物及人体标本水平上，深一层次地解析EGFR糖基化及EMT-MET在肾间质纤维化中作用的新机理，为开拓以糖基化修饰为靶点治疗肾间质纤维化这一新途径奠定实验基础。. 本项目研究成果：目前在投SCI文章3篇；特邀国际肾脏病大会学术报告（口头报告）1次；获得国家专利1项；以本项目成果为申报基础及作为主要成员获得国家自然科学基金重点项目1项及辽宁省科技进步一等奖；培养硕士研究生2名；2名研究人员获得国家自然科学基金资助；研究结果受到国际肾脏病权威专家（美国肾脏病学会前任主席，现哈佛医学院肾内科及生物医学工程科主任Joseph V. Bonventre教授以及韩国肾脏病学会秘书长，梨花女子大学医学院肾内科Duk-Hee Kang教授）的关注及称赞；并亲笔来函表达了与本项目负责人开展合作的期望及赴其实验室进行成果转化的邀请。