MiR-214 protects MC3T3-E1 osteoblasts against H2O2-induced apoptosis by suppressing oxidative stress and targeting ATF4.

OBJECTIVE: Fragility fracture is one of the common complications of osteoporosis. Elevated oxidative stress-induced apoptosis is thought to be one of the unfavorable factors to osteoblastic dysfunction, which increased the risk of bone fracture. However, the molecular mechanisms for oxidative stress-induced osteoblast cells apoptosis still need to be elucidated. This study aims to investigate the protective function of miR-214 in H2O2-induced apoptosis of MC3T3-E1 osteoblasts.

MATERIALS AND METHODS: MC3T3-E1 cells were treated with 400 μM H2O2. Flow cytometry was adopted to detect the apoptosis rate; malondialdehyde (MDA) and glutathione peroxidase (Gpx) levels were used to determine the reactive oxygen species (ROS) level. Reverse transcription-polymerase chain reaction (RT-PCR) was employed to test the expression level of miR-214 and ATF4. After transfected MC3T3-E1 cells with miR-214 mimics and inhibitor, RT-PCR was used to detect activating transcription factor 4 (ATF4) expression level.

RESULTS: H2O2 treatment increased ROS induced intracellular oxidative injury. Flow cytometry showed that 400 μM H2O2 induced the apoptosis of MC3T3-E1 cells. Moreover, RT-PCR showed decreased expression level of MiR-214. Furthermore, the apoptosis induced by high ROS level was reversed by increased miR-214 expression level. The regulatory ability of MiR-214 to apoptosis is by regulating ATF4 expression.

CONCLUSIONS: miR-214 plays a protective role in H2O2 induced MC3T3 osteoblasts apoptosis and its protective effect is proceeded by regulating ROS level and ATF4 expression level.