Zou Yezi, Chen Zhiquan, Li Jie, Gong Wenyan, Zhang Lei, Xu Futian, Chen Lihao, Liu Peiqing, Huang Heqing
Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China.
Department of Laboratory Medicine, Guangdong Second Provincial General Hospital, Guangzhou, China.
Front Endocrinol (Lausanne). 2018 Jun 7;9:275. doi: 10.3389/fendo.2018.00275. eCollection 2018.
Progestin and adipoQ receptor 3 (PAQR3), is a Golgi-anchored membrane protein containing seven transmembrane helices. It has been demonstrated that PAQR3 mediates insulin resistance, glucose and lipid metabolism, and inflammation. In addition, kidney inflammatory fibrosis is an important pathological feature of diabetic nephropathy (DN). Therefore, we aimed to investigate the role of PAQR3 in diabetic kidney fibrosis as well as inflammation in DN.
The effect of PAQR3 on NF-κB signaling pathway, expressions of fibronectin (FN) and intercellular adhesion molecule-1 (ICAM-1) in glomerular mesangial cells (GMCs) cultured by high glucose (HG) were examined.
Diabetic mouse and rat models were induced by streptozotocin (STZ). GMCs were treated with HG and transfected with PAQR3 plasmids or small-interfering RNA targeting PAQR3 or NF-κB. The protein levels of FN and ICAM-1 were examined by Western blotting, and the transcriptional activity and DNA binding activity of NF-κB were measured by dual luciferase reporter assay and electrophoretic mobility shift assay (EMSA). The interaction between PAQR3 and IKKβ (inhibitor of nuclear factor κB kinase β) was analyzed by co-immunoprecipitation.
PAQR3 was increased in both STZ-induced diabetic models and HG-treated GMCs. PAQR3 overexpression further increased HG-induced FN and ICAM-1 upregulation. In contrast, silencing of PAQR3 suppressed the expressions of FN and ICAM-1. PAQR3 overexpression promoted the nuclear accumulation, DNA binding activity, and transcriptional activity of NF-κB. Mechanically, PAQR3 directly interacted with IKKβ. The upregulation effect of PAQR3 overexpression on the expressions of FN and ICAM-1 was abolished by the treatment of NF-κB siRNA or PDTC (ammonium pyrrolidinedithiocarbamate) in HG-treated GMCs.
PAQR3 promotes the expressions of FN and ICAM-1 activating NF-κB signaling pathway. Mechanistically, PAQR3 activates NF-κB signaling pathway to mediate kidney inflammatory fibrosis through direct interaction with IKKβ in DN.
孕激素和脂联素受体3（PAQR3）是一种定位于高尔基体的膜蛋白，含有7个跨膜螺旋。已有研究表明，PAQR3介导胰岛素抵抗、葡萄糖和脂质代谢以及炎症反应。此外，肾脏炎性纤维化是糖尿病肾病（DN）的重要病理特征。因此，我们旨在研究PAQR3在DN肾脏纤维化及炎症中的作用。
检测PAQR3对高糖（HG）培养的肾小球系膜细胞（GMCs）中核因子κB（NF-κB）信号通路、纤连蛋白（FN）和细胞间黏附分子1（ICAM-1）表达的影响。
用链脲佐菌素（STZ）诱导建立糖尿病小鼠和大鼠模型。用HG处理GMCs，并转染PAQR3质粒或靶向PAQR3或NF-κB的小干扰RNA。通过蛋白质免疫印迹法检测FN和ICAM-1的蛋白水平，用双荧光素酶报告基因检测法和电泳迁移率变动分析（EMSA）测定NF-κB的转录活性和DNA结合活性。通过免疫共沉淀分析PAQR3与核因子κB激酶β（IKKβ）之间的相互作用。
在STZ诱导的糖尿病模型和HG处理的GMCs中，PAQR3均升高。PAQR3过表达进一步增加了HG诱导的FN和ICAM-1上调。相反，敲低PAQR3可抑制FN和ICAM-1的表达。PAQR3过表达促进了NF-κB的核内聚集、DNA结合活性和转录活性。机制上，PAQR3直接与IKKβ相互作用。在HG处理的GMCs中，用NF-κB小干扰RNA或吡咯烷二硫代氨基甲酸铵（PDTC）处理可消除PAQR3过表达对FN和ICAM-1表达的上调作用。
PAQR3通过激活NF-κB信号通路促进FN和ICAM-1的表达。机制上，在DN中PAQR3通过与IKKβ直接相互作用激活NF-κB信号通路，介导肾脏炎性纤维化。
