TRIB3 Promotes Osteogenic Differentiation of Human Adipose-derived Mesenchymal Stem Cells Levelled by Post-transcriptional Regulation of miR-24-3p.

OBJECTIVE: To explore the effect of TRIB3 on the osteogenic differentiation of human adipose-derived mesenchymal stem cells (hASCs) and reveal the potential role of TRIB3 in bone regeneration. METHODS: TRIB3-knockdown and TRIB3-overexpression hASCs were used to explore the effect of TRIB3 on osteogenic differentiation by alkaline phosphatase (ALP) staining, alizarin red S (ARS) staining, quantitative real-time polymerase chain reaction (qRT-PCR) and heterotopic bone formation. The regulation of miR-24-3p on TRIB3 was detected by qRT-PCR and western blot. Ribonucleic acid (RNA) sequencing was performed to investigate the downstream regulatory network of TRIB3. RESULTS: TRIB3 promoted the osteogenic differentiation of hASCs both in vitro and in vivo. This process was regulated epigenetically by the post-transcriptional regulation of miR-24-3p, which could bind directly to the three prime untranslated region (3'UTR) of TRIB3 and inhibit TRIB3 expression. The downstream regulatory network of TRIB3-mediated osteogenic differentiation was related to calcium ion binding and cell metabolism, extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and nuclear factor-κB (NF-κB) signalling pathways. CONCLUSION: TRIB3 is a promising therapeutic target for hASC-based bone tissue engineering and the epigenetic regulation of TRIB3 through miR-24-3p permits regulatory controllability, thus promoting osteogenesis through an important metabolic target while obtaining a safe and controllable effect via post-transcriptional epigenetic regulation.

Transcriptomics and Functional Analysis of Graphene-Guided Osteogenic Differentiation of Mesenchymal Stem Cells.

OBJECTIVE: To explore graphene's effects on the gene expression profile of mesenchymal stem cells, and to reveal the mechanisms of graphene-guided osteogenic differentiation. METHODS: Human adipose-derived mesenchymal stem cells (hASCs) were cultured on single-layer graphene-coated titanium disks or titanium disks in proliferation medium (control) or osteoinduction medium for 7 days before RNA extraction. After library construction and RNA sequencing, identification of differentially expressed genes was performed through Limma package of R platform, with a cut-off value of log fold change (logFC) > = |1|. Pathway and Gene ontology (GO) analyses were conducted on DAVID Bioinformatics Resources 6.8 (NIAID/NIH). Network analyses were performed by the Ingenuity Pathways Analysis (IPA). RESULTS: Signalling pathway analysis revealed the top five pathways - cytokine-cytokine receptor interaction, neuroactive-ligand receptor interaction, calcium signalling pathway, PI3K-Akt signalling pathway and cell adhesion molecules. GO analyses demonstrated significant changes on cell adhesion, calcium signalling, and epigenetic regulation. IPA network analyses demonstrated that inflammation-related pathways were influenced by graphene, while the downstream factors of histone H3 and H4 were also altered especially under the existence of osteoinduction medium. CONCLUSION: Graphene promotes osteogenic differentiation of hASCs mainly by influencing cell adhesion, cytokine-cytokine receptor interactions, inflammatory responses, and potentially influences histone H3 and H4 through epigenetic regulation.

[Promoted role of bone morphogenetic protein 2/7 heterodimer in the osteogenic differentiation of human adipose-derived stem cells].

OBJECTIVE: To investigate the role of bone morphogenetic protein 2/7 heterodimer (BMP-2/7) in the osteogenesis of human adipose-derived stem cells (hASCs). METHODS: hASCs were exposed to three different treatments in vitro: osteogenic medium with 150 µg/L BMP-2/7 (experimental group), osteogenic medium alone (OM group) and proliferation medium (PM group). After 1, 4 and 7 days of osteogenic induction, the amount of cellular DNA was measured to investigate the cytotoxicity. After 7 and 14 days, alkaline phosphatase (ALP) staining and quantification were performed to test the activity of ALP. After 21 and 28 days, the calcification deposition was determined by Alizarin Red S (ARS) staining and quantification. The expressions of the osteoblast-related genes were tested on days 1, 4, 7 and 14. In the in vivo study, 6 nude mice were used and 4 groups were set and implanted subcutaneously into the back of nude mice: (1) ß-TCP scaffold only (scaffold control group); (2) ß-TCP scaffold with hASCs cultured by PM in vitro for 1 week (PM control group); (3) ß-TCP scaffold with hASCs cultured by OM in vitro for 1 week (OM control group); (4) ß-TCP scaffold with hASCs cultured by OM with 150 µg/L BMP-2/7 in vitro for 1 week (test group). After 4 weeks of implantation, histological staining was performed to evaluate the in vivo osteogenesis of hASCs. RESULTS: After induction for 1 day, there was no significant difference between the experimental group and the PM group on the cellular DNA content (P>0.05). After 4 days, the cellular DNA content increased under the stimulation of BMP-2/7 (P<0.05). On day 7, there was no significant difference among the three groups (P>0.05). ALP activity was higher by the induction of BMP-2/7 than in OM alone and PM (P<0.05). More mineralization deposition and more expressions of osteoblast-related genes such as Runx2, ALP, COL-1A1 and OC were determined in the experimental group at different time points (P<0.05). HE staining showed that, in the test group and OM control group, the extracellular matrix (ECM) with eosinophilic staining were observed around hASCs, and newly-formed bone-like tissues could be found in ECM around the scaffold materials. Moreover, compared with the OM control group, more bone-like tissues could be observed in ECM with typical structure of bone tissue in the test group. Masson's trichrome staining showed that more expression of collagen could be observed in ECM in the test group compared with the other groups. There was small amount of expression of collagen in the OM and PM control groups. No obvious positive results were found in the scaffold group. CONCLUSION: BMP-2/7 heterodimer plays a significant role in the osteogenesis of hASCs and is able to enhance the osteogenic differentiation of hASCs in vitro and in vivo.

The effect of simvastatin on chemotactic capability of SDF-1α and the promotion of bone regeneration.

The purpose of this study was to investigate the cooperative effects of simvastatin (SIM) and stromal cell-derived factor-1α (SDF-1α) on the osteogenic and migration capabilities of mesenchymal stem cells (MSCs), and construct a cell-free bone tissue engineering system comprising SIM, SDF-1α and scaffold. We found that 0.2 µm SIM significantly increased alkaline phosphatase activity (P < 0.05) of mouse bone marrow MSCs with no inhibition of cell proliferation, and enhanced the chemotactic capability of SDF-1α (P < 0.05). Next, we constructed a novel cell-free bone tissue engineering system using PLGA loaded with SIM and SDF-1α, and applied it in critical-sized calvarial defects in mice. New bone formation in the defect was evaluated by micro-CT, HE staining and immunohistochemistry. The results showed that PLGA loaded with SIM and SDF-1α promoted bone regeneration significantly more than controls. We investigated possible mechanisms, and showed that SDF-1α combined with SIM increased MSC migration and homing in vivo, promoted angiogenesis and enhanced the expression of BMP-2 in newly-formed bone tissue. In conclusion, SIM enhanced the chemotactic capability of SDF-1α and the cell-free bone tissue engineering system composed of SIM, SDF-1α and scaffold promoted bone regeneration in mouse critical-sized calvarial defects.

[Application of patient-participated digital design in esthetic rehabilitation of anterior teeth].

OBJECTIVE: To explore a new method of patient-involved digital design, esthetic outcome prediction and fabrication for the esthetic rehabilitation of anterior teeth, and to provide an alternative choice for the restoration of anterior teeth. METHODS: In this study, 32 patients with esthetic problems in their anterior teeth were included and divided into two groups randomly: the experimental group (16 patients) and control group (16 patients). In the experimental group, the dentition and facial images were obtained by intra-oral scanning and Three-dimensional (3D) facial scanning and then calibrated. The design of the rehabilitation and the esthetic outcome prediction were created by computer-aided design (CAD) software. After morphologic modification according to the patients' opinions, prostheses were fabricated according to the final design by computer-aided manufacturing (CAM) equipment. As for the control group, the regular design method was applied to restore their anterior teeth. The time consuming in the first insertion of each restoration in both groups was recorded. The quality of the prostheses was assessed by another prosthedontist. The satisfaction to prostheses and the facial appearance were evaluated by the patients. RESULTS: The process of the patient-involved digital design and outcome anticipation was successfully established. The patients were satisfied with the esthetic effects of the anterior restoration made by the digital technique. The acceptance rate of the patients on the digital rehabilitation in the experimental group was 100%. There was no significant difference of the quality of the prostheses between the two groups. The satisfaction rate of the patients on prostheses and facial appearance was significantly higher in the experimental group than in the control group (P < 0.05). In addition, the time consuming in the first insertion of the experimental group was much shorter than that in the control group (P < 0.01). CONCLUSION: The new method of the patient-involved digital design, esthetic outcome prediction and fabrication for the esthetic rehabilitation of anterior teeth is a practical technique. This method is useful in shortening the time consuming of the restoration of anterior teeth and improving the patient satisfaction with the esthetic outcome.

[Effect of human adipose-derived stromal cells on osteogenesis in vivo].

OBJECTIVE: To explore the effect of human adipose-derived stromal cells (hASCs) on the osteogenesis during the process of bone formation in vivo, and to lay the foundation of further investigations on the mechanism of in vivo osteogenesis of hASCs. METHODS: hASCs were isolated from adipose tissue by the method of collagenase digestion, and were routinely proliferated and passaged. In the in vivo study 16 nude mice were used and 4 groups were set and implanted subcutaneously into the back of nude mice: (1) blank; (2) ß-tricalcium phosphate (ß-TCP) scaffold only (scaffold control group); (3) ß-TCP scaffold with human fibroblasts (negative cell control group); (4) ß-TCP scaffold with hASCs (test group). After 1 week, 2 weeks, 4 weeks and 6 weeks of implantation, samples from the 4 nude mice were collected at each time point. Scanning electron microscope (SEM) observation and histological staining were performed to evaluate the in vivo osteogenesis of hASCs. RESULTS: SEM images showed that large amount of extracellular matrix (ECM) could be observed around hASCs in test group after 2 weeks of implantation. At the time point of 4 weeks, mineral deposit was found in ECM. At the time point of 6 weeks, the mineral deposit was observed to increase significantly. HE staining showed that the ECM with eosinophilic staining could be observed around hASCs after 2 weeks of implantation. At the time point of 4 weeks, newly-formed bone-like tissue could be found in ECM around the scaffold materials. At the time point of 6 weeks, more bone-like tissues were observed in ECM with typical structure of bone tissue. In comparison, no obvious mineralization and bone-like tissue were found in other groups. CONCLUSION: hASCs play important roles in the process of osteogenesis in vivo, including secretion of large amount of ECM, acceleration of the mineralization of ECM and guidance for the formation of bone-like tissues.