Gene expression profiling of osteoblasts subjected to dexamethasone-induced apoptosis with/without GSK3β-shRNA

Objective: Glucocorticoids (GCs)-induced osteoblast apoptosis has been identified as an important cause of GCs related osteonecrosis of the femoral head (ONFH). Glycogen synthase kinase 3 beta (GSK3 beta) has been proved to mediate dexamethasone (Dex)-induced osteoblast apoptosis. This study aimed to investigate the underlying mechanism of GSK3 beta in Dex-induced osteoblast apoptosis. Methods: Osteoblast cells were transfected with lentivirus expressing GSK3 beta-shRNA, and a DNA microarray was performed to analyze gene expression after Dex treatment with or without GSK3 beta-shRNA. Some differentially expressed genes were further validated by quantitative real-time-PCR (qRT-PCR). Results: 460 genes were up-regulated (at least 2-fold) with Dex treatment but down-regulated (at least 2-fold) with GSK3 beta-shRNA treatment. In addition, 315 genes were down-regulated (at least 2-fold) with Dex treatment but up-regulated (at least 2-fold) with GSK3 beta-shRNA treatment. Among these genes, the apoptosis-related genes Hoxb8, Kifl8a, Dock8, Dlk1, Tnfsf14, Casq2, Bcl2l14 and mechanosensation-related gene Piezo2 were selected for further qRT-PCR analysis. 7 of 8 genes (Piezo2, Hoxb8, Kif18a, Dlk1, Tnfsfl4, Casq2, Bcl2l14) showed the same tendency between gene chip results and qRT-PCR results. The microarray data also showed that apoptotic pathway, MAPK pathway, TGF beta pathway and Wnt pathway might be related to the mechanism of GSK3 beta in Dex-induced osteoblast apoptosis. Conclusion: Our findings indicate that GSK3 beta-shRNA treatment can alter various genes expression levels and change diverse signaling pathways involved in Dex-induced osteoblast apoptosis. Furthermore, Piezo2, Hoxb8, Kifl8a, Dlk1, Tnfsfl4, Casq2 and Bcl2l14 genes may play an important role in the GSK3 beta-mediated osteoblast apoptosis process. (C) 2018 Elsevier Inc. All rights reserved.