title: Elevated transcriptional co-activator p102 mediates angiotensin II type 1 receptor up-regulation and extracellular matrix overproduction in the high glucose-treated rat glomerular mesangial cells and isolated glomeruli.
abstract: P102 is a multifunctional transcriptional co-activator. This experiment is designed to investigate the role of p102 in the activation of renin-angiotensin system (RAS) and sequentially extracellular matrix (ECM) over synthesis in diabetic nephropathy. Rat glomerular mesangial cells (MCs) or isolated glomeruli were cultured in normal glucose (NG, 5.5mM) or high glucose (HG, 25 mM) DMEM. The generation of reactive oxygen species was measured by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescent probe assay. The protein levels were analyzed by Western blot and the mRNA levels were evaluated by real-time PCR. HG treatment induced an increase in reactive oxygen species production. Culturing the cells in HG for 48 h, p102 mRNA and protein, angiotensin II type 1 receptor (AT1 receptor) mRNA, transforming growth factor-β1 (TGF-β1) and fibronectin proteins were significantly increased. NADPH oxidase inhibitor DPI blocked the HG-induced p102, TGF-β1 and fibronetcin elevations. Knockdown on p102 expression by siRNA depressed the HG-induced AT1 receptor up-regulation as well as the increases in TGF-β1 and fibronectin. In contrast, AT1 receptor antagonist candesartan did not influence p102 levels under either NG or HG condition, but blocked the HG-induced TGF-β1 and fibronectin increases. The results from isolated glomeruli were consistent with that of MCs, which showed that HG exposure stimulated the expression of p102. These results suggest that the overproduction of reactive oxygen species at the early stage of HG incubation stimulates p102 synthesis, which in turn up-regulates AT1 receptor expression. The activation of RAS stimulates TGF-β1 and fibronectin production, which further results in ECM accumulation.
authors: Department of Physiology and Pathophysiology, Shanghai Medical College, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China.
authors: Zhen
authors: Z
authors: Wang
authors: Jun
authors: J
authors: Ni
authors: Decui
authors: D
authors: Shao
authors: Jia
authors: J
authors: Liu
authors: Yang
authors: Y
authors: Shen
authors: Li
authors: L
authors: Zhou
authors: Yu
authors: Y
authors: Huang
authors: Chen
authors: C
authors: Yu
authors: Jun
authors: J
authors: Wang
authors: Hong
authors: H
authors: Xue
authors: Limin
authors: L
authors: Lu
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004720:Endonucleases; D005109:Extracellular Matrix / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D005947:Glucose / Q000008:administration & dosage*; D007678:Kidney Glomerulus / Q000187:drug effects / Q000378:metabolism*; D050527:Mesangial Cells / Q000187:drug effects / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D005353:Fibronectins; D009687:Nuclear Proteins; D017382:Reactive Oxygen Species; D044140:Receptor, Angiotensin, Type 1; D053773:Transforming Growth Factor beta1; D004720:Endonucleases; C490639:Snd1 protein, rat; D005947:Glucose