Effect of high glucose on glomerular endothelial-mesenchymal transition and its possible mechanism / 中华肾脏病杂志

ABSTRACT

Objective To investigate whether high glucose can induce endothelial-mesenchymal transition (EndMT) in glomerular endothelial cells and the role of TGF-β in the process.Methods Rat glomerular endothelial cells were divided into five groupsnormal glucose (NG,5.5mmol/L),high glucose (HG,15,30 mmol/L),TGF-β inhibition (HG+ LY36,30 mmol/L glucose + 10 μmol/L LY364947),hyperosmotic control (M,5.5 mmol/L glucose+25.5 mmol/L mannitol) and solvent control (D,5.5 mmol/L glucose + 1 ml/L DMSO).Western blotting was performed to detect relative protein quantities of endothelial marker claudin 5 and mesenchymal marker α-smooth muscle actin (α-SMA).TGF-β1 and TGF-β2 mRNA levels were measured by real-time PCR.Vascular endothelial marker VE-cadherin and mesenchymal marker α-SMA were detected by immunofluorescent stain and observed by confocal microscopy.Results Compared with NG,the expression of claudin5 protein in HG (15 or 30 mmol/L) was up-regulated while expression of α-SMA protein was down-regulated (P ＜0.05).Both TGF-β1 and TGF-β2 mRNA levels increased as well (P ＜ 0.05).However,when compared with HG,the claudin 5 levels increased while α-SMA decreased in TGF-β inhibition group.No significant changes were observed in hyperosmotic or solvent control group.Confocal microscopy showed the transformation of cells from a cobblestone-liked shape to a spindle one,and a decreasing expression of VE-cadherin while an increasing α-SMA in HG group (P ＜ 0.05),whereas TGF-β inhibition partly attenuated those changes in both morphological and protein levels.Conclusions High glucose treatment of glomerular endothelial cells results in an increase in the level of TGF-β1 and TGF-β2 mRNA and leads to endothelial-mesenchymal transiton.Inhibition of TGF-β partly prevents this process,indicating that TGF-β plays a crucial role in high-glucose-induced glomerular endothelial-mesenchymal transiton.