Shijun Zhang1, Wenliang Wu1, Guangjun Jiao1, Ci Li1, Haichun Liu2. 1. Department of Orthopedics, Qilu Hospital of Shandong University, Jinan, 250012, China. 2. Department of Orthopedics, Qilu Hospital of Shandong University, Jinan, 250012, China. Electronic address: haichunliu56@163.com.
Abstract
BACKGROUND: The important role of miR-455-3p in the pathogenesis of bone metabolism associated diseases is gradually emerging. This study aims to ascertain the involvement of miR-455-3p and its underlying mechanisms in osteoporosis. METHODS: The osteoblast cell lines MC3T3-E1 was treated with ferric ammonium citrate (FAC) to mimic a pathological environment for osteoporosis. The cytotoxic effect of iron overload was assessed by proliferation, apoptosis and oxidative stress of osteoblasts using commercial kits. Molecular biological methods, including qRT-PCR analysis, cell transfection and luciferase reporter assays were used to explain the role of miR-455-3p and its potential mechanisms in osteoblast apoptosis. RESULTS: FAC dramatically inhibited the proliferation of osteoblast cells MC3T3-E1 but increased the apoptosis. We also observed that FAC significantly down-regulated miR-455-3p in MC3T3-E1 cells but enhanced HDAC2 protein level. Moreover, miR-455-3p overexpression eliminated the effects of iron overload on osteoblast cell proliferation, apoptosis and oxidative stress. In addition, miR-455-3p regulated osteoblast cell proliferation, apoptosis and oxidative stress through regulating HDAC2-Nrf2/ARE signaling pathway. MiR-455-3p overexpression alleviated the oxidative stress injury in osteoporosis mice. CONCLUSION: Our results demonstrated that miR-455-3p activated Nrf2/ARE signal pathway through suppressing Keap1 via negative regulating HDAC2 protein level, thereby suppressing oxidative stress and promoting osteoblasts growth.
BACKGROUND: The important role of miR-455-3p in the pathogenesis of bone metabolism associated diseases is gradually emerging. This study aims to ascertain the involvement of miR-455-3p and its underlying mechanisms in osteoporosis. METHODS: The osteoblast cell lines MC3T3-E1 was treated with ferric ammonium citrate (FAC) to mimic a pathological environment for osteoporosis. The cytotoxic effect of iron overload was assessed by proliferation, apoptosis and oxidative stress of osteoblasts using commercial kits. Molecular biological methods, including qRT-PCR analysis, cell transfection and luciferase reporter assays were used to explain the role of miR-455-3p and its potential mechanisms in osteoblast apoptosis. RESULTS: FAC dramatically inhibited the proliferation of osteoblast cells MC3T3-E1 but increased the apoptosis. We also observed that FAC significantly down-regulated miR-455-3p in MC3T3-E1 cells but enhanced HDAC2 protein level. Moreover, miR-455-3p overexpression eliminated the effects of iron overload on osteoblast cell proliferation, apoptosis and oxidative stress. In addition, miR-455-3p regulated osteoblast cell proliferation, apoptosis and oxidative stress through regulating HDAC2-Nrf2/ARE signaling pathway. MiR-455-3p overexpression alleviated the oxidative stress injury in osteoporosismice. CONCLUSION: Our results demonstrated that miR-455-3p activated Nrf2/ARE signal pathway through suppressing Keap1 via negative regulating HDAC2 protein level, thereby suppressing oxidative stress and promoting osteoblasts growth.