Overexpression of hsa-miR-125b during osteoblastic differentiation does not influence levels of Runx2, osteopontin, and ALPL gene expression

Abstract

Multipotent mesenchymal stromal cells (MSCs) were first isolated from bone marrow and then from various adult tissues including placenta, cord blood, deciduous teeth, and amniotic fluid. MSCs are defined or characterized by their ability to adhere to plastic, to express specific surface antigens, and to differentiate into osteogenic, chondrogenic, adipogenic, and myogenic lineages. Although the molecular mechanisms that control MSC proliferation and differentiation are not well understood, the involvement of microRNAs has been reported. In the present study, we investigated the role of miR-125b during osteoblastic differentiation in humans. We found that miR-125b increased during osteoblastic differentiation, as well as Runx2 and ALPL genes. To study whether the gain or loss of miR-125b function influenced osteoblastic differentiation, we transfected MSCs with pre-miR-125b or anti-miR-125b and cultured the transfected cells in an osteoblastic differentiation medium. After transfection, no change was observed in osteoblastic differentiation, and Runx2, OPN, and ALPL gene expression were not changed. These results suggest that the gain or loss of miR-125b function does not influence levels of Runx2, OPN, and ALPL during osteoblastic differentiation.

The role of microRNAs in bone remodeling

“… 40 In addition, miR-125b is significantly increased in the hMSCs derived from senile osteoporotic patients, and osterix (Osx) levels change, 41 establishing the potential role of miR-125b in bone disease therapy, although a contradiction occurred in the ‘gain and loss' experiments of miR-125b in vitro . 42 In this case, miRNAs and their targets vary accordingly across different osteogenesis stages, and in vivo research is needed to elucidate the mechanism.…”

Implication of the p53-Related miR-34c, -125b, and -203 in the Osteoblastic Differentiation and the Malignant Transformation of Bone Sarcomas

“…These data sustain the inhibitory role of miR-125b on vascular calcification, possibly through its ability to modulate the expression of RUNX2, even if no direct targeting was exhibited here. On the other hand, another group showed no modulation in RUNX2, OPN, and ALP gene expressions subsequent to the gain or loss of miR-125b in MSCs [78]. Interestingly, these investigators reported an increase in the expression level of this miRNA during the osteoblastic differentiation of such cells.…”

“…Down-regulating this miRNA in such resistant cell lines sensitizes them to doxorubicin, vincristine, and etoposide, thus suggesting its implication in the regulation of a multidrug-resistance pathway. In addition, its increased expression throughout the course of human mesenchymal stem cell (MSC) differentiation into the osteoblastic lineage also implicates miRNA-125b in this process [78].…”

MicroRNA and Human Bone Health

“…In C3H10T1/2 cells, overexpression of miR‐125b inhibited osteoblast differentiation by targeting Cbfβ, a key transcription osteogenic inducer, and in turn reduced Runx2 expression . However, this effect was not observed in another study using human MSCs . No study so far has evaluated miR‐125b's role in osteoclastogenesis.…”