miR-182 is a strong negative regulator of osteoblast proliferation, differentiation and skeletogenesis through targeting FoxO1

Abstract

Uncontrolled oxidative stress impairs bone formation and induces age-related bone loss in humans. The FoxO family is widely accepted to play an important role in protecting diverse cells from reactive oxygen species (ROS). Activation of FoxO1, the main FoxO in bone, stimulates proliferation and differentiation and inhibits apoptosis of osteoblast lineage cells. Despite the important role of FoxO1, little is known about how FoxO1 expression in bone is regulated. Meanwhile, several recent studies reported that microRNAs (miRNAs) could play a role in osteoblast differentiation and bone formation by targeting various transcriptional factors. Here, one additional crucial miRNA was identified, miR-182, which regulates osteoblastogenesis by repressing FoxO1 and thereby negatively affecting osteogenesis. Overexpression of miR-182 in osteoblast lineage cells increased cell apoptosis and inhibited osteogenic differentiation, while in vivo overexpression of miR-182 in zebrafish impaired bone formation. From in silico analysis and validation experiments, FoxO1 was identified as the target of miR-182, and restoration of FoxO1 expression in miR-182 overexpressing osteoblasts rescued them from the inhibitory effects of miR-182. These results indicate that miR-182 functions as FoxO1 inhibitor to antagonize osteoblast proliferation and differentiation, with a subsequent negative effect on osteogenesis. To treat bone aging, an antisense approach targeting miR-182 could be of therapeutic value.