Protein kinase Cβ_2 mediated high glucose-induced human umbilical vein endothelial cells injury via regulation of peroxisome proliferator-activated receptor α

Objective To investigate the roles of protein kinase C(PKC)β_2 and PPARα in the mRNA expression of vascular endothelial growth factor(VEGF)and vascular cell adhesion molecule-1(VCAM-1)in human umbilical vein endothelial cells(HUVECs)exposed to high glucose,and to explore their relationship.Methods The HUVECs were divided into eight groups:normal glucose(NG,5 mmoL/L D-glucose)group,high glucose(HG,25 mmol/L D-ucose)group,osmotic control(L,NG+20 mmol/L L-glucose)group,normal glucose transfected with empty vector(NN,NG+AdS-null)group,high glucose transfected with PKCβ_2(HB,HG+Ad5-PKCβ_2)group,high glucose plus fenofibrate(HF,HG+40 μmol/L fenofibrate)group,and HB plus fenofibrate (HBF,HB+40μmol/L fenofibrate)group.HUVECs were incubated with fenofibrate for 20 minutes as HF20 group.All cells in various groups were cultured for 6 days.The expressions of VEGF and VCAM-1 mRNA were detected by RT-PCR.PPARα protein expression was tested by Western blot.The expression and traaslocation of PKCβ_2 protein were observed by confocal laser scanning microscopo.Results (1)HG increased VEGF and VCAM-1 mRNA expressions,with 1.91 and 1.56 folds of NG group,respectively(both P<0.05).VEGF and VCAM-1 mRNA expressions in HB group further increased,with 2.59 and 2.07 folds of NG group,respectively(both P<0.05).Fenofibrate significantly decreased VEGF and VCAM-1 mRNA expressions,with 68%and 74%of HG group,respectively(both P<0.05).There were no significant difierences in the expressiong of VEGF,VCAM-1 mRNA between HF20 and HG groups.(2)The protein expression of PPARα decreased by 20%in HG group compared with NG group,and further decreased in HB group,being 78%of HG group.Compared with HG group,PPARαexpression increased by 13%in HF group(P<0.05).(3)HG induced PKCβ_2 translocation from cytosol to nucleus and quantitative analysis showed the ratio of plasma/nuclear fluorescence intensity in HG group decreased by 37% compared with NG group(P<0.05).The PKCβ_2 translocation was more obvious in HB group than in HG group.Conclusion Hiigll glucose stimulates VEGF and VCAM-1 mRNA expressions in HUVECs via PKCβ_2 activationdependent PPARα pathway. Key words: Protein kinase Cβ_2; PPARα; Human umbilical vein endothelial ceHs; Glucose; Retinopathies; diabctic