Progestin and AdipoQ Receptor 3 Upregulates Fibronectin and Intercellular Adhesion Molecule-1 in Glomerular Mesangial Cells via Activating NF-κB Signaling Pathway Under High Glucose Conditions.

Yezi Zou,Peiqing Liu,Wenyan Gong,Lei Zhang,Futian Xu,Jie Li,Heqing Huang,Zhiquan Chen,Lihao Chen

doi:10.3389/fendo.2018.00275

Abstract

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 via activating NF-κB signaling pathway. Mechanistically, PAQR3 activates NF-κB signaling pathway to mediate kidney inflammatory fibrosis through direct interaction with IKKβ in DN.

Highlights

Diabetic nephropathy (DN), known as glomerulosclerosis, is believed to be a common chronic microvascular complication of diabetes, and the most prevalent cause of middle-late renal fibrosis [1,2,3]
Our data showed that high glucose (HG) stimulation significantly increased the expressions of FN and intercellular adhesion molecule-1 (ICAM-1), which was further increased by Progestin and adipoQ receptor 3 (PAQR3) overexpression (Figures 2A,B)
These results suggested that the upregulation of PAQR3 by HG promotes renal inflammatory fibrosis

Summary

Introduction

Diabetic nephropathy (DN), known as glomerulosclerosis, is believed to be a common chronic microvascular complication of diabetes, and the most prevalent cause of middle-late renal fibrosis [1,2,3]. The main pathological characteristic of DN is glomerular sclerosis resulting from microvascular pathological changes induced by diabetes It is a leading cause of morbidity and mortality in patients with DN [4]. The accumulated extracellular matrix (ECM) components (such as fibronectin, FN) and inflammatory mediators (such as cell adhesion molecules, ICAM-1) in GMCs are involved in glomerular basement membrane thickening and glomerular fibrosis [3, 8, 9]. The activated NF-κB signaling pathway promotes the excessive expression of inflammatory mediators, which results in continuous or amplifying inflammatory responses and the secretion of ECM, eventually causing diabetic renal fibrosis. Object: 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

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