To investigate the effect of oligodeoxynucleotides (ODNs) on the differentiation of rat bone marrow mesenchymal stem cells (BMSCs) to osteoblasts, in order to find a candidate ODN with potential for the treatment of periodontitis, a series of ODNs were designed and selected to test their effect on the promotion of the differentiation of BMSCs to osteoblasts in vitro and on the repair of periodontal tissue in rats with periodontitis. It was found that MT01, one of the ODNs with the sequences of human mitochondrial DNA, stimulated the proliferation of BMSCs, the differentiation of BMSCs to osteoblasts and mRNA expression of bone-associated factors including Runx2, Osterix, OPG, RANKL and collagen I in vitro. In vivo study showed that MT01 prevented the loss of alveolar bone in the rats with periodontitis and induced the production of proteins of OPG and Osterix in the bone tissue. These results indicated that MT01 could induce differentiation of BMSCs to osteoblasts and inhibit the alveolar bone absorption in rats with periodontitis.

The paper explored the regulatory role of oligodeoxynucleotides (ODNs) with specific sequences in the proliferation and activation of osteoblast, using human osteoblast-like cell line MG 63 as the model. Through the administration of ODNs to MG 63 cells at a concentration of 1.0 µg/mL, ODN MT01 with positive effects on proliferation and activation of osteoblast was selected from 11 different ODNs by methyl thiazolyl tetrazolium (MTT) assay and alkaline phosphatase (ALP) activity measurement. To get a deeper insight into the molecular mechanism, effects of ODN MT01 treatment on the expression level of Sp7, runx-2, collagen-I, osteoprotegerin (OPG) and RANK ligand (RANKL) were determined using quantitative real time PCR and Western blotting. Remarkably, the mRNA and protein expression levels of Sp7, runx-2, collagen-I and OPG were improved after ODN MT01 treatment. Meanwhile, the protein expression level of RANKL was dramatically decreased. These results suggested that ODN MT01 had a significant impact in facilitating osteogenic proliferation and activation, and provided a direct evidence for the notion that single strand ODN could regulate the balance of bone formation and resorption, and thus was of great potential in the rebuilding of alveolar bone.

N -AC- L -Leu-PEI-mediated miR-34a delivery improves osteogenic differentiation under orthodontic force N-AC-L-Leu-PEI-mediated miR-34a delivery improves osteogenic differentiation under orthodontic force

An oligodeoxynucleotide (ODN), with its design based on human mitochondrial DNA (MT01), has been demonstrated to promote the proliferation and activation of osteoblasts. However, critical issues such as poor oligonucleotide stability in the presence of nucleases currently limit its broad application. This study evaluated whether N-isopropylacrylamide-modified polyethylenimine (PEN) nanoparticles could effectively deliver ODN MT01 locally with low or no toxicity and promote osteoblast differentiation in vitro. Our data demonstrate that at a w/w ratio of 6 : 1, PEN/MT01 nanoparticles were effectively transfected into MG63 cells without cytotoxicity, whereby they promoted cell proliferation in vitro. Quantitative PCR and western blotting analyses showed that the PEN/MT01 complexes enhanced mRNA and protein expression of osteoprotegerin, Sp7, and runt-related transcription factor 2, and decreased levels of receptor activator of nuclear factor kappa-B ligand, which are markers indicative of MG63 differentiation into preosteoblasts or mature osteoblasts. This approach demonstrates the potential of using PEN as a biocompatible gene therapy carrier to address regeneration of bone defects.