Yuqin Shen

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.

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.

To study the effect of basic fibroblast growth factor (bFGF) on the gene expression of syndecan-4 by human periodontal ligament cell (PDLC) in culture, and discuss the effect of bFGF on human PDLC proliferation and migration. 68 adolescent (12-18 years old) health premolar were collected, which were extracted for orthodontic reason. Human PDLC were cultured and stimulated by exogenous bFGF. After cultured 24, 48, 72h, gene expression of syndecan-4 was detected by SYBR green quantitative real time polymerase chain reaction. The mRNA expression of syndecan-4 in 24 h group increased markedly than that in control group (P < 0.01), expecially in 1.0 ng x mL(-1) group. 1.0 ng x mL(-1) group in 48 h higher than that control group (P < 0.05). 1.0 ng x mL(-1) group in 72h compared with control group was lower (P < 0.05). The mRNA expression of syndecan-4 was increased by bFGF at the beginning, but the expression was decreased with the time. The expression of such changes may be one of the important factors which participate in the migration process of PDLC.