Osteogenesis and mineralization in a rabbit mandibular distraction osteogenesis model is promoted by the human LMP-1 gene

The effects of SDF-1 combined application with VEGF on femoral distraction osteogenesis in rats

Bone regeneration and mineralization can be achieved by means of distraction osteogenesis (DO). In the present study, we investigated the effect of stromal cell-derived factor 1 (SDF-1) and vascular endothelial growth factor (VEGF) on the new bone formation during DO in rats. Forty-eight Sprague-Dawley rats were randomized into four groups of 12 rats each. We established the left femoral DO model in rats and performed a mid-femoral osteotomy, which was fixed with an external fixator. DO was performed at 0.25 mm/12 h after an incubation period of 5 days. Distraction was continued for 10 days, resulting in a total of 5 mm of lengthening. After distraction, the solution was locally injected into the osteotomy site, once a day 1 ml for 1 week. One group received the solvent alone and served as the control, and the other three groups were treated with SDF-1, VEGF, and SDF-1with VEGF in an aqueous. Sequential X-ray radiographs were taken two weekly. The regeneration was monitored with the use of micro-CT analysis, mechanical testing, and histology. Radiographs showed accelerated regenerate ossification in the SDF-1, VEGF, and SDF-1 with the VEGF group, with a larger amount of new bone compared with the control group, especially SDF-1 with the VEGF group. Micro-CT analysis and biomechanical tests showed Continuous injection of the SDF-1, VEGF, and SDF-1 with VEGF during the consolidation period significantly increased bone mineral density bone volume, mechanical maximum loading, and bone mineralization of the regenerate. Similarly, the expression of osteogenic-specific genes, as determined by real-time polymerase chain reaction , was significantly higher in SDF-1 with the VEGF group than in the other groups. Histological examination revealed more new trabeculae in the distraction gap and more mature bone tissue for the SDF-1 with the VEGF group. SDF-1 and VEGF promote bone regeneration and mineralization during DO, and there is a synergistic effect between the SDF-1 and VEGF. It is possible to provide a new and feasible method to shorten the period of treatment of DO.

PDZ and LIM Domain-Encoding Genes: Their Role in Cancer Development

PDZ-LIM family proteins (PDLIMs) are a kind of scaffolding proteins that contain PDZ and LIM interaction domains. As protein-protein interacting molecules, PDZ and LIM domains function as scaffolds to bind to a variety of proteins. The PDLIMs are composed of evolutionarily conserved proteins found throughout different species. They can participate in cell signal transduction by mediating the interaction of signal molecules. They are involved in many important physiological processes, such as cell differentiation, proliferation, migration, and the maintenance of cellular structural integrity. Studies have shown that dysregulation of the PDLIMs leads to tumor formation and development. In this paper, we review and integrate the current knowledge on PDLIMs. The structure and function of the PDZ and LIM structural domains and the role of the PDLIMs in tumor development are described.

Recent advances in gene-enhanced bone tissue engineering

The loss of bone tissue represents a critical clinical condition that is frequently faced by surgeons. Substantial progress has been made in the area of bone research, providing insight into the biology of bone under physiological and pathological conditions, as well as tools for the stimulation of bone regeneration. The present review discusses recent advances in the field of gene-enhanced bone tissue engineering. Gene transfer strategies have emerged as highly effective tissue engineering approaches for supporting the repair of the musculoskeletal system. By contrast to treatment with recombinant proteins, genetically engineered cells can release growth factors at the site of injury over extended periods of time. Of particular interest are the expedited technologies that can be applied during a single surgical procedure in a cost-effective manner, allowing translation from bench to bedside. Several promising methods based on the intra-operative genetic manipulation of autologous cells or tissue fragments have been developed in preclinical studies. Moreover, gene therapy for bone regeneration has entered the clinical stage with clinical trials for the repair of alveolar bone. Current trends in gene-enhanced bone engineering are also discussed with respect to the movement of the field towards expedited, translational approaches. It is possible that gene-enhanced bone tissue engineering will become a clinical reality within the next few years.

CKIP-1 silencing promotes new bone formation in rat mandibular distraction osteogenesis

OBJECTIVE

This study investigated the effects and possible molecular mechanism of casein kinase-2 interacting protein-1 (CKIP-1) silencing on bone regeneration during rat mandibular distraction osteogenesis (DO).

STUDY DESIGN

CKIP-1 silencing by chitosan/si-CKIP-1 was employed and analyzed both in rat mandibular DO models in vivo and in cultured rat mandible bone marrow stromal cells (BMSCs) in vitro.

RESULTS

Gross observation, micro-computed tomography analysis, and hematoxylin and eosin (H&E) staining revealed that new bone formation in the distraction gap of the chitosan/si-CKIP-treated group was better compared with the chitosan/si-NC and phosphate buffered saline-treated groups in both quantity and quality. Proliferation assay, flow cytometry, and alizarin red staining indicated that CKIP-1 silencing significantly inhibited apoptosis, but promoted osteogenic differentiation of cultured BMSCs. Additionally, CKIP-1 silencing significantly promoted the expression of Wnt3 a, β-catenin, and osteocalcin both in new bone formation of DO models in vivo and in the osteogenic differentiation process of BMSCs in vitro.

CONCLUSIONS

Promotion of bone formation after CKIP-1 silencing in rat mandibular distraction osteogenesis appears to be mediated through the Wnt3 a/β-catenin signaling pathway.

Triptolide induces the cell apoptosis of osteosarcoma cells through the TRAIL pathway

Research on triptolide, a diterpenoid epoxide found in the Thunder God Vine Tripterygium wilfordii, has increased our knowledge of the pharmacology, pharmacokinetics, toxicology and clinical application of this agent. In the present study, we aimed to identify the effects of triptolide on the apoptosis of osteosarcoma cells and to evaluate the anti-proliferative action of this agent. MG-63 cells were treated either with various doses of triptolide (50, 100 or 200 nM) or DMSO for 6, 12 and 24 h. Treatment with triptolide effectively suppressed the cell viability and induced the apoptosis of osteosarcoma MG-63 cells as detected by MTT assay and flow cytometry, respectively. In addition, by using caspase-3, caspase-8 and caspase-9 activity assays and western blot analysis, the anticancer effects of triptolide against osteosarcoma growth were found to involve activation of the DR-5/p53/Bax/caspase-9/ caspase-3 signaling pathway and the DR-5/FADD/caspase-8/lysosomal/cathepsin B/caspase-3 signaling pathway in the MG-63 cells. An important factor in the anticancer effects of triptolide against osteosarcoma was TRAIL-DR-5. The data suggest that triptolide may be a potential novel chemotherapeutic agent for osteosarcoma and acts through the TRAIL-DR-5 signaling pathway.