MiR-27a-3p promotes the osteogenic differentiation by activating CRY2/ERK1/2 axis.BACKGROUND
 It was reported that miR-27a-3p reduced the symptoms of osteoporosis.  However, the mechanism by which miR-27a-3p in osteogenic differentiation remains largely unknown.


 RT-qPCR was used to evaluate the mRNA expression of miR-27a-3p and CRY2 in cells.  Luciferase reporter gene assay was used to analyze the correlation between CRY2 and miR-27a-3p.


 The expression of miR-27a-3p and the phosphorylation level of ERK1/2 were increased by OIM in MC3T3-E1 cells, while CRY2 expression was decreased.  In addition, OIM-induced increase of calcified nodules, ALP content and osteogenesis-related protein expression was significantly reversed by downregulation of miR-27a-3p and overexpression of CRY2.  In addition, miR-27a-3p directly targeted CRY2 and negatively regulated CRY2.  Meanwhile, the inhibitory effect of miR-27a-3p inhibitor on osteogenic differentiation was reversed by knockdown of CRY2 or using honokiol (ERK1/2 signal activator).  Furthermore, miR-27a-3p significantly inhibited the apoptosis of MC3T3-E1 cells treated by OIM.  Taken together, miR-27a-3p/CRY2/ERK axis plays an important role in osteoblast differentiation.


 MiR-27a-3p promoted osteoblast differentiation via mediation of CRY2/ERK1/2 axis.  Thereby, miR-27a-3p might serve as a new target for the treatment of osteoporosis.
MiR-27a-3p
MiR-27a-3p promotes the osteogenic differentiation by activating CRY2/ERK1/2 axis.BACKGROUND
 MiR-27a-3p promoted osteoblast differentiation via mediation of CRY2/ERK1/2 axis. 
CRY2/ERK1/2 axis
RT-qPCR was used to evaluate the mRNA expression of miR-27a-3p and CRY2 in cells. 
RT-qPCR
The protein levels of CRY2, Runt-related transcription factor 2 (Runx2), osteopontin (OPN), osteocalcin (OCN) and the phosphorylation level of extracellular regulated protein kinases (ERK) 1/2 in MC3T3-E1 cells were evaluated by western blotting. 
Western blotting
Luciferase reporter gene assay was used to analyze the correlation between CRY2 and miR-27a-3p.



Luciferase reporter gene assay
Meanwhile, calcium nodules and ALP activity were tested by alizarin red staining and ALP kit, respectively. 
ALP kit
Meanwhile, calcium nodules and ALP activity were tested by alizarin red staining and ALP kit, respectively. 
Alizarin red staining