Functional Analysis of miR-148a: A Differentially Expressed microRNA in Hemifacial Microsomia.

Introduction: Hemifacial Microsomia (HFM) is the second most common congenital deformity, yet its etiology and pathogenesis remain unclear. Therefore, this study aimed to identify differentially expressed microRNAs (miRNAs) between healthy and affected bone marrow mesenchymal stem cells (BMSCs) from HFM patients, focusing on the functional roles of miR-148a in osteogenesis and osteoclastogenesis.

Methods: The specific expression of microRNAs was screened by sequencing and verified by PCR. Through the use of mimics, inhibitors, and knockout technology, we controlled the expression of miR-148a in vivo and in vitro. Osteogenesis and osteoclastogenesis induction, PCR, western blot, ALP staining, alizarin red staining, TRAP staining, micro-CT, and tissue sections were performed to explore the effects of miR-148 on osteogenesis and osteoclastogenesis.

Results: MiR-148a was identified and confirmed through our research as a differentially expressed miRNA in HFM. Overexpression of miR-148a increased osteogenesis-related gene and protein expression and mineralized calcium nodule formation while decreasing osteoclast-related gene and protein levels. Silencing or knockout of miR-148a produced opposite effects. miR-148a knockout mice were smaller than wild-type, with reduced osteogenesis, fewer trabeculae, increased trabecular bone separation in the mandible, and decreased ramus length. Additionally, local overexpression of miR-148a in knockout mice increased local bone mass.

Discussions: The current study findings demonstrate that miR-148a can influence the bone volume, and its role in chondrogenesis deserves further research. Additionally, further studies on the changes upstream of miR-148a that lead to differences in miR-148a expression between the healthy and affected sides of HFM patients and the differences in bone size are warranted to better understand HFM pathogenesis.

Conclusion: Our findings suggest that the opposing effects of miR-148a on osteogenesis and osteoclastogenesis lead to decreased bone mass in HFM. Local overexpression can reverse bone defects caused by miR-148a, suggesting its promising role in future treatments. We anticipate that further investigations will enhance our understanding and ultimately pave the way for the application of these insights in clinical settings for disease treatment.