Bone morphogenetic protein-7 upregulates genes associated with osteoblast differentiation, including collagen I, Sp7 and IBSP in gingiva-derived stem cells

Inflammatory and bone remodelling related biomarkers following periodontal transplantation of the tissue engineered biocomplex

OBJECTIVES

To assess gingival crevicular fluid (GCF) levels of inflammatory and bone remodelling related biomarkers following transplantation of a tissue-engineered biocomplex into intrabony defects at several time-points over 12-months.

MATERIALS AND METHODS

Group-A (n = 9) received the Minimal Access Flap (MAF) surgical technique combined with a biocomplex of autologous clinical-grade alveolar bone-marrow mesenchymal stem cells in collagen scaffolds enriched with an autologous fibrin/platelet lysate (aFPL). Group-B (n = 10) received the MAF surgery, with collagen scaffolds enriched with aFPL and Group-C (n = 8) received the MAF surgery alone. GCF was collected from the osseous defects of subjects via paper strips/30 sec at baseline, 6-weeks, 3-, 6-, 9-, 12-months post-surgery. Levels of inflammatory and bone remodelling-related biomarkers in GCF were determined by ELISA.

RESULTS

Group-A demonstrated significantly higher GCF levels of BMP-7 at 6-9 months than baseline, with gradually decreasing levels of pro-inflammatory and pro-osteoclastogenic markers (TNF-α, RANKL) over the study-period; and an overall decrease in the RANKL/OPG ratio at 9-12 months than baseline (all p < 0.001). In comparison, only modest interim changes were observed in Groups-B and -C.

CONCLUSIONS

At the protein level, the approach of MAF and biocomplex transplantation provided greater tissue regeneration potential as cell-based therapy appeared to modulate inflammation and bone remodelling in residual periodontal defects.

CLINICAL RELEVANCE

Transplantation of a tissue engineered construct into periodontal intrabony defects demonstrated a biochemical pattern for inflammatory control and tissue regeneration over 12-months compared to the control treatments. Understanding the biological healing events of stem cell transplantation may facilitate the design of novel treatment strategies.

CLINICAL DATABASE REGISTRATION

ClinicalTrials.gov ID: NCT02449005.

Ablation of FAM20C caused short root defects via suppressing the BMP signaling pathway in mice

Short root defects are prone to cause various periodontal diseases and lead to tooth loss in some serious cases. Studies about the mechanisms governing the development of the root are needed for a better understanding of the pathogenesis of short root defects. The protein family with sequence similarity 20 group C (FAM20C) is a Golgi casein kinase that has been well studied in the development of tooth crown formation. However, whether FAM20C plays a role in the development of tooth root is still unknown. Thus, we generated Sox2-Cre;Fam20cfl/fl (cKO) mice, in which Fam20c was ablated in both the dental epithelium and dental mesenchyme, and found that the cKO mice showed severe short root defects mainly by inhibiting the development of dental mesenchyme in the root region. In this investigation, we found morphological changes and differentiation defects, with reduced expression of dentin sialophosphoprotein (DSPP) in odontoblasts of the root region in cKO mice. Furthermore, the proliferation rate of apical papillary cells was reduced in the root of cKO mice. In addition, the levels of bone morphogenetic protein 4 (BMP4) and phospho-Smad1/5/8, and that of Osterix and Krüppel-like factor 4 (KLF4), two downstream target molecules of the BMP signaling pathway, were significantly reduced in the root of cKO mice. These results indicate that FAM20C plays an essential role in the development of the root by regulating the BMP signaling pathway.

Physicochemical cues are not potent regulators of human dermal fibroblast trans-differentiation

Due to their inherent plasticity, dermal fibroblasts hold great promise in regenerative medicine. Although biological signals have been well-established as potent regulators of dermal fibroblast function, it is still unclear whether physiochemical cues can induce dermal fibroblast trans-differentiation. Herein, we evaluated the combined effect of surface topography, substrate rigidity, collagen type I coating and macromolecular crowding in human dermal fibroblast cultures. Our data indicate that tissue culture plastic and collagen type I coating increased cell proliferation and metabolic activity. None of the assessed in vitro microenvironment modulators affected cell viability. Anisotropic surface topography induced bidirectional cell morphology, especially on more rigid (1,000 kPa and 130 kPa) substrates. Macromolecular crowding increased various collagen types, but not fibronectin, deposition. Macromolecular crowding induced globular extracellular matrix deposition, independently of the properties of the substrate. At day 14 (longest time point assessed), macromolecular crowding downregulated tenascin C (in 9 out of the 14 groups), aggrecan (in 13 out of the 14 groups), osteonectin (in 13 out of the 14 groups), and collagen type I (in all groups). Overall, our data suggest that physicochemical cues (such surface topography, substrate rigidity, collagen coating and macromolecular crowding) are not as potent as biological signals in inducing dermal fibroblast trans-differentiation.

Coating Ti6Al4V implants with nanocrystalline diamond functionalized with BMP-7 promotes extracellular matrix mineralization in vitro and faster osseointegration in vivo

The present study investigates the effect of an oxidized nanocrystalline diamond (O-NCD) coating functionalized with bone morphogenetic protein 7 (BMP-7) on human osteoblast maturation and extracellular matrix mineralization in vitro and on new bone formation in vivo. The chemical structure and the morphology of the NCD coating and the adhesion, thickness and morphology of the superimposed BMP-7 layer have also been assessed. The material analysis proved synthesis of a conformal diamond coating with a fine nanostructured morphology on the Ti6Al4V samples. The homogeneous nanostructured layer of BMP-7 on the NCD coating created by a physisorption method was confirmed by AFM. The osteogenic maturation of hFOB 1.19 cells in vitro was only slightly enhanced by the O-NCD coating alone without any increase in the mineralization of the matrix. Functionalization of the coating with BMP-7 resulted in more pronounced cell osteogenic maturation and increased extracellular matrix mineralization. Similar results were obtained in vivo from micro-CT and histological analyses of rabbit distal femurs with screws implanted for 4 or 12 weeks. While the O-NCD-coated implants alone promoted greater thickness of newly-formed bone in direct contact with the implant surface than the bare material, a further increase was induced by BMP-7. It can be therefore concluded that O-NCD coating functionalized with BMP-7 is a promising surface modification of metallic bone implants in order to improve their osseointegration.

The Gingiva from the Tissue Surrounding the Bone to the Tissue Regenerating the Bone: A Systematic Review of the Osteogenic Capacity of Gingival Mesenchymal Stem Cells in Preclinical Studies

The current review aims to systematically assess the osteogenic capacity of gingiva-derived mesenchymal stem cells (GMSCs) in preclinical studies. A comprehensive electronic search of PubMed, Embase, Web of Science, and Scopus databases, as well as a manual search of relevant references, was performed in June 2020 without date or language restrictions. Eligibility criteria were the following: studies that compared mesenchymal stem cells (MSCs) derived from the gingiva with other MSC sources (in vitro or in vivo) or cell-free scaffold (in vivo) and studies that reported at least one of the following outcomes: osteogenic potential and new bone formation for in vitro and in vivo, respectively. Moreover, the assessment of included studies was conducted using appropriate guidelines. From 646 initial retrieved studies, 35 full-text articles were subjected to further screening and 26 studies were selected (20 in vitro studies and 6 in vivo studies). GMSCs showed great proliferation capacity and expressed recognized mesenchymal stem cell markers, particularly CD90. In vitro, MSC sources including GMSCs were capable of undergoing osteogenic differentiation with less ability in GMSCs, while most in vivo studies confirmed the capacity of GMSCs to regenerate bony defects. Concerning the assessment of methodological quality, in vitro studies met the relevant guideline except in five areas: the sample size calculation, randomization, allocation concealment, implementation, and blinding, and in vivo publications had probably low risk of bias in most domains except in three areas: allocation concealment, attrition, and blinding items.

NELL-1 Increased the Osteogenic Differentiation and mRNA Expression of Spheroids Composed of Stem Cells

Background and objectives: NELL-1 is a competent growth factor and it reported to target cells committed to the osteochondral lineage. The secreted, osteoinductive glycoproteins are reported to rheostatically control skeletal ossification. This study was performed to determine the effects of NELL-1 on spheroid morphology and cell viability and the promotion of osteogenic differentiation of stem cell spheroids. Materials and Methods: Cultures of stem cell spheroids of gingiva-derived stem cells were grown in the presence of NELL-1 at concentrations of 1, 10, 100, and 500 ng/mL. Evaluations of cell morphology were performed using a microscope, and cell viability was assessed using a two-color assay and Cell Counting Kit-8. Evaluation of the activity of alkaline phosphatase and calcium deposition assays involved anthraquinone dye assay to determine the level of osteogenic differentiation of cell spheroids treated with NELL-1. Real-time quantitative polymerase chain reaction (qPCR) was used to evaluate the expressions of RUNX2, BSP, OCN, COL1A1, and β-actin mRNAs. Results: The applied stem cells produced well-formed spheroids, and the addition of NELL-1 at tested concentrations did not show any apparent changes in spheroid shape. There were no significant changes in diameter with addition of NELL-1 at 0, 1, 10, 100, and 500 ng/mL concentrations. The quantitative cell viability results derived on Days 1, 3, and 7 did not show significant disparities among groups (p > 0.05). There was statistically higher alkaline phosphatase activity in the 10 ng/mL group compared with the unloaded control on Day 7 (p < 0.05). A significant increase in anthraquinone dye staining was observed with the addition of NELL-1, and the highest value was noted at 10 ng/mL (p < 0.05). qPCR results demonstrated that the mRNA expression levels of RUNX2 and BSP were significantly increased when NELL-1 was added to the culture. Conclusions: Based on these findings, we conclude that NELL-1 can be applied for increased osteogenic differentiation of stem cell spheroids.

Recent Advances of Osterix Transcription Factor in Osteoblast Differentiation and Bone Formation

With increasing life expectations, more and more patients suffer from fractures either induced by intensive sports or other bone-related diseases. The balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption is the basis for maintaining bone health. Osterix (Osx) has long been known to be an essential transcription factor for the osteoblast differentiation and bone mineralization. Emerging evidence suggests that Osx not only plays an important role in intramembranous bone formation, but also affects endochondral ossification by participating in the terminal cartilage differentiation. Given its essentiality in skeletal development and bone formation, Osx has become a new research hotspot in recent years. In this review, we focus on the progress of Osx's function and its regulation in osteoblast differentiation and bone mass. And the potential role of Osx in developing new therapeutic strategies for osteolytic diseases was discussed.

Morphological stability, cellular viability and stem cell marker expression of three-dimensional cultures of stem cells from bone marrow and periodontium

The aim of the present study was to evaluate the morphology, cellular viability and stem cell marker expression of three-dimensional cultures of bone marrow and gingiva-derived stem cells in different ratios. Stem cell spheroids were made with bone marrow and gingiva-derived stem cells using ratios of 6:0 (Group 1), 4:2 (Group 2), 3:3 (Group 3), 2:4 (Group 4) and 0:6 (Group 5), respectively. The viability of cell spheroids was analyzed using a Live/Dead kit assay and a Cell Counting Kit-8 assay. Total RNA extraction and reverse transcription-quantitative PCR were performed to detect the mRNA expression levels of Nanog and β-actin in each group. Stem cell spheroids were well formed in silicone elastomer-based concave microwells with different ratios of bone marrow and gingiva-derived stem cells. The shape of the spheroids and their viability were maintained throughout the entirety of the experimental procedure. Statistically significant increases in spheroid diameters were noted in Groups 4 and 5 on day 1 when compared with Group 1 on day 1. There was a significant increase in the cell viability values seen in Group 3 on day 1 when compared with Group 1 on day 1. Highest levels of Nanog expression was seen in Group 3 on day 10, but the increase was not significant when compared with Group 1 on day 1. Co-culturing with higher ratios of gingiva-derived stem cells produced stem cell spheroids with larger diameters and increased cellular viability. This co-culture technique may be used in stem cell therapy with allogenic stem cell transplantation.

The Effects of Morinda citrifolia (Noni) on the Cellular Viability and Osteogenesis of Stem Cell Spheroids

Background and objectives: Morinda citrifolia (Noni) has been widely used in herbal remedies to treat and prevent various kinds of diseases. We conducted this study to evaluate the effects of Noni extract on the maintenance of morphology, the improvement of cellular viability, and the enhancement of osteogenesis of stem cell spheroids. Materials and Methods: We cultured stem cell spheroids made with gingiva-derived stem cells in the presence of Noni extract at concentrations of 10, 100 and 200 ng/mL. We performed analysis of the cell morphology and changes in the cellular viability. We conducted alkaline phosphatase activity assays using a kit, and mineralization assays using an anthraquinone dye to evaluate the osteogenesis of stem cell spheroids with the addition of Noni extract. Results: The applied cells formed spheroids well, and the addition of Noni at 10, 100 and 200 ng/mL concentrations did not produce significant morphological changes. The quantitative values for cellular viability on Day 3 showed that the absorbance values at 450 nm were 0.314 ± 0.013, 0.318 ± 0.008, 0.304 ± 0.000 and 0.300 ± 0.011 for Noni at 0, 10, 100 and 200 ng/mL concentrations, respectively. The results of alkaline phosphatase activity with absorbance values at 405 nm were 0.189 ± 0.019, 0.174 ± 0.023, 0.192 ± 0.014 and 0.210 ± 0.062 for Noni at 0, 10, 100 and 200 ng/mL concentrations, respectively, on Day 4. There were significantly higher values of Alizarin Red S staining for Noni in the 10, 100 and 200 ng/mL groups, with the highest value at 100 ng/mL when compared with the unloaded control on Day 14. Conclusions: Based on these findings, we concluded that Noni extract might be applied for the enhanced osteogenic differentiation of stem cell spheroids.