miR-27a-3p negatively regulates osteogenic differentiation of MC3T3-E1 preosteoblasts by targeting osterix

Osteoporosis is a complex multifactorial disorder characterized by microarchitectural deterioration, low bone mass, and increased risk of fractures or broken bones. Balanced bone remodeling is tightly regulated by the differentiation, activity and apoptosis of bone-forming osteoblasts and bone-resorbing osteoclasts. MicroRNAs (miRs) are dysregulated in osteoporosis, but whether they control osteogenic differentiation and skeletal biology, or could serve as therapeutic targets remains to be elucidated. The present study identified miR-27a-3p as a critical suppressor of osteoblastogenesis. Bioinformatics analysis and luciferase reporter assays demonstrated that miR-27a-3p directly targeted and controlled the expression of osterix (Osx), an early response gene essential for bone formation, through its 3′-untranslated region. miR-27a-3p functionally inhibited the differentiation of preosteoblasts by decreasing Osx expression, which synergistically contributed to bone formation. miR-27a-3p level was significantly decreased during osteogenic differentiation and increased in the serum of patients with osteoporosis. Together, miR-27a-3p contributed to diminished osteogenic function during osteogenic differentiation and might thus serve as a therapeutic target and diagnostic biomarker for osteoporosis.