MicroRNA-29a Inhibition Induces Gab1 Upregulation To Protect OB-6 Human Osteoblasts From Hydrogen Peroxide

Oxidative stress induces death of human osteoblasts via modulating intracellular signaling pathways.However,the underlying mechanism remains unclear.The present study determines the role of the Gab1(GRB2 associated binding protein 1)in hydrogen peroxide(H2O2)-induced death of human osteoblasts.We show that Gabl is required for H2O2-induced Akt activation to promote osteoblast survival.In OB-6 human osteoblasts,Gab1 knockdown(by targeted-shRNA)or complete knockout(by CRISPR-Cas9 KO plasmid)largely attenuated Akt activation by H2O2.Gab1-deficient OB-6 cells were more vulnerable to H2O2.Conversely,forced over-expression of Gab1 by an adenovirus vector increased Akt activation to protect OB-6 cells from H2O2.Significantly,the anti-sense of microRNA-29a("antagomiR-29a"),the anti-Gab1 microRNA,induced Gab1 expression to facilitate H2O2-induced Akt activation,which protected OB-6 cells from apoptosis.The antagomiR-29a was ineffective in Gabl-deficient and Akt-inhibited OB-6 cells.Forced over-expression of miR-29a by a lentiviral vector induced Gab1 downregulation to inhibit H2O2-induced Akt activation,thus exacerbating OB-6 cell apoptosis.However miR-29a's actions were abolished by an adenovirus constitutively-active Aktl(Ad-caAktl).Finally,miR-29a-3p upregulation and Gab1 mRNA downregulation were observed in human necrotic femoral head tissues.Together,we conclude that microRNA-29a inhibition induces Gab1 upregulation and Akt activation to protect OB-6 osteoblasts from H2O2.