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J Bone Miner Res. 2017 Dec;32(12):2466-2475. doi: 10.1002/jbmr.3230. Epub 2017 Aug 28.

Overexpression of MiR-335-5p Promotes Bone Formation and Regeneration in Mice.

Author information

1
Division of Oral Biology, Tufts University School of Dental Medicine, Boston, MA, USA.
2
Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
3
Department of Orthopaedic Surgery, University of Connecticut, Farmington, CT, USA.
4
Periodontology and Implant Dentistry, New York University College of Dentistry, New York, NY, USA.
5
Department of Anatomy and Cell Biology, Tufts University School of Medicine, Sackler School of Graduate Biomedical Sciences, Boston, MA, USA.

Abstract

MicroRNAs (miRNAs) and the Wnt signaling pathway play critical roles in regulating bone development and homeostasis. Our previous study revealed high expression of miR-335-5p in osteoblasts and hypertrophic chondrocytes in mouse embryos and the ability of miR-335-5p to promote osteogenic differentiation by downregulating Wnt antagonist Dickkopf-1 (DKK1). The purpose of this study was to investigate the effects of miR-335-5p constitutive overexpression on bone formation and regeneration in vivo. To that end, we generated a transgenic mouse line specifically overexpressing miR-335-5p in osteoblasts lineage by the osterix promoter and characterized its bone phenotype. Bone histomorphometry and μCT analysis revealed higher bone mass and increased parameters of bone formation in transgenic mice than in wild-type littermates. Increased bone mass in transgenic mice bones also correlated with enhanced expression of osteogenic differentiation markers. Upon osteogenic induction, bone marrow stromal cells (BMSCs) isolated from transgenic mice displayed higher mRNA expression of osteogenic markers than wild-type mice BMSCs cultures. Protein expression of Runx2 and Osx was also upregulated in BMSC cultures of transgenic mice upon osteogenic induction, whereas that of DKK1 was downregulated. Most important, BMSCs from transgenic mice were able to repair craniofacial bone defects as shown by μCT analysis, H&E staining, and osteocalcin (OCN) immunohistochemistry of newly formed bone in defects treated with BMSCs. Taken together, our results demonstrate constitutive overexpression of miR-335-5p driven by an osterix promoter in the osteoblast lineage induces osteogenic differentiation and bone formation in mice and support the potential application of miR-335-5p-modified BMSCs in craniofacial bone regeneration.

KEYWORDS:

BONE FORMATION; DKK1; MIR-335-5P; OSTEOGENIC DIFFERENTIATION; TRANSGENIC MOUSE; WNT

PMID:
28846804
PMCID:
PMC5732062
DOI:
10.1002/jbmr.3230
[Indexed for MEDLINE]
Free PMC Article

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