Effects of Gly-LDL on LRP5/DKK1 Pathway in MC3T3-E1 Osteoblasts

Abstract

Background: The aim of this study was to investigate the effect of glycated low density lipoprotein (Gly-LDL) on the proliferation, differentiation and expression of low-density lipoprotein receptor-related protein-5 (LRP5), dickkopf-1(DKK1) in mouse MC3T3-E1 cells. Methods: The MC3T3-E1 cells of mouse were cultured with native LDL(n-LDL) without chemical, and various levels of Gly-LDL was cultured respectively with 5mmol/L(A), 20mmol/L(B), 100mmol/L(C) of D+glucose for 4 weeks) for 48h. The proliferation of MC3T3-E1 cell was measured by CCK8, the osteocalcin level in the medium was determined by ELISA, the mRNA expression of LRP5,β-catenin and DKK1 was analysed by real-time PCR and proteins in Wnt signaling pathway by western blot. Results: After cells incubation with group A of Gly-LDL, the inhibition of MC3T3-E1 cells was apparently promoted than that of n-LDL control group (P<0.01),The higher Gly-LDL level the more inhibited. The effects of Gly-LDL on the proliferation of MC3T3-E1 was dose-dependent under certain conditions. The levels of Osteocalcin in cells cultured with Gly-LDL were significantly inhibited compared with the control group. The mRNA expression of DKK1 was significantly up-regulated while the mRNA expression of β-catenin and LRP5 were down-regulated(P<0.01) in MC3T3-E1 cells, which cultured with group A Gly-LDL. According to the results of western blot, it also showed that, compared with n-LDL group,the effect of Gly-LDL on osteoblasts was down-regulated the LRP5 and β-catenin while up-reglulated the DKK1. Conclusions: The Wnt signaling pathway being involved might be the possible mechanism of Gly-LDL effect on the proliferation and differentiation in MC3T3-E1 cells. Disclosure T. Lei: None. L. Chen: None. B. Zhang: None. W. Tang: None.