Pulsed Electromagnetic Field Regulates MicroRNA 21 Expression to Activate TGF-β Signaling in Human Bone Marrow Stromal Cells to Enhance Osteoblast Differentiation.

Author: Selvamurugan N1, He Z2, Rifkin D3, Dabovic B3, Partridge NC2
Affiliation:
1Department of Biotechnology, School of Bioengineering, SRM University, Kattankulathur, Tamil Nadu, India.
2Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, USA.
3Department of Cell Biology, New York University School of Medicine, New York, NY, USA.
Conference/Journal: Stem Cells Int.
Date published: 2017
Other: Volume ID: 2017 , Pages: 2450327 , Special Notes: doi: 10.1155/2017/2450327. Epub 2017 Apr 23. , Word Count: 209


Pulsed electromagnetic fields (PEMFs) have been documented to promote bone fracture healing in nonunions and increase lumbar spinal fusion rates. However, the molecular mechanisms by which PEMF stimulates differentiation of human bone marrow stromal cells (hBMSCs) into osteoblasts are not well understood. In this study the PEMF effects on hBMSCs were studied by microarray analysis. PEMF stimulation of hBMSCs' cell numbers mainly affected genes of cell cycle regulation, cell structure, and growth receptors or kinase pathways. In the differentiation and mineralization stages, PEMF regulated preosteoblast gene expression and notably, the transforming growth factor-beta (TGF-β) signaling pathway and microRNA 21 (miR21) were most highly regulated. PEMF stimulated activation of Smad2 and miR21-5p expression in differentiated osteoblasts, and TGF-β signaling was essential for PEMF stimulation of alkaline phosphatase mRNA expression. Smad7, an antagonist of the TGF-β signaling pathway, was found to be miR21-5p's putative target gene and PEMF caused a decrease in Smad7 expression. Expression of Runx2 was increased by PEMF treatment and the miR21-5p inhibitor prevented the PEMF stimulation of Runx2 expression in differentiating cells. Thus, PEMF could mediate its effects on bone metabolism by activation of the TGF-β signaling pathway and stimulation of expression of miR21-5p in hBMSCs.

PMID: 28512472 PMCID: PMC5420424 DOI: 10.1155/2017/2450327

BACK