Basic fibroblast growth factor regulates phosphate/pyrophosphate regulatory genes in stem cells isolated from human exfoliated deciduous teeth

The growth factor multimodality on treating human dental mesenchymal stem cells: a systematic review

BACKGROUND

Ensuring the quantity, quality, and efficacy of human dental mesenchymal stem cells (MSCs) has become an urgent problem as their applications increase. Growth factors (GFs) have low toxicity, good biocompatibility, and regulate stem cell survival and differentiation. They bind to specific receptors on target cells, initiating signal transduction and triggering biological functions. So far, relatively few studies have been conducted to summarize the effect of different GFs on the application of dental MSCs. We have reviewed the literature from the past decade to examine the effectiveness and mechanism of applying one or multiple GFs to human dental MSCs. Our review is based on the premise that a single dental MSC cannot fulfill all applications and that different dental MSCs react differently to GFs.

METHODS

A search for published articles was carried out using the Web of Science core collection and PubMed. The study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines. This review considered studies from 2014 to 2023 that examined the effects of GFs on human dental MSCs. The final selection of articles was made on the 15th of July 2023.

RESULTS

Three thousand eight hundred sixty-seven pieces of literature were gathered for this systematic review initially, only 56 of them were selected based on their focus on the effects of GFs during the application of human dental MSCs. Out of the 56, 32 literature pieces were focused on a single growth factor while 24 were focused on multiple growth factors. This study shows that GFs can regulate human dental MSCs through a multi-way processing manner.

CONCLUSION

Multimodal treatment of GFs can effectively regulate human dental MSCs, ensuring stem cell quality, quantity, and curative effects.

BFGF attenuates aortic valvular interstitial cell calcification by inhibiting endoplasmic reticulum stress-mediated apoptosis

The potential protective effect of basic fibroblast growth factor (BFGF) on the cardiovascular system has been proposed previously, however, its effect on calcific aortic valve disease (CAVD) and underlying mechanisms have not been elucidated. The valvular interstitial cell (VIC) were isolated from porcine aortic valve leaflets. To investigate the effect of BFGF on osteogenic differentiation of VIC, the osteogenic induced medium (OIM) and BFGF were added. The protein expression level was detected by Western blot, and apoptosis was determined by flow cytometry. The effect of BFGF on CAVD process in vivo was assessed by a rat CAVD model, which was identified by echocardiography and Alizarin red staining. The expression level of BFGF in the aortic valve and serum were significantly upregulated in CAVD patients compared to control group. In addition, exogenous BFGF injection attenuates CAVD process in vivo. The protein markers of osteogenic differentiation, endoplasmic reticulum stress (ERS), and apoptosis were significantly upregulated by culture with OIM. On the contrary, the aforementioned proteins were suppressed after adding 100 ng/mL of BFGF. Inhibition of PI3K/Akt and ERK1/2 pathways by specific inhibitors abolished the protective effect of BFGF. In conclusion, BFGF could alleviate the VIC calcification by inhibiting ERS-mediated apoptosis, which is partly regulated by activation of the PI3K/Akt and ERK1/2 signaling pathways. BFGF may provide a potential avenue for CAVD therapy.

Effects of Growth Factors on the Differentiation of Dental Stem Cells: A Systematic Review and Meta-analysis (Part I)

INTRODUCTION

To evaluate the biological interaction between dental stem cells (DSCs) and different growth factors in the field of regenerative endodontics.

METHODS

A systematic search was conducted in the electronic databases up to October 2021. This study followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Ex vivo studies evaluating the biological interactions of DSCs and growth factors were included. The meta-analysis was performed according to the type of growth factor. The outcomes were cell viability/ proliferation and mineralization. Standardized mean differences (SMDs) were estimated using the random-effect maximum-likelihood method (P < .05). Additional analysis was performed to find any potential source of heterogeneity.

RESULTS

Twenty articles were included in the systematic review; meta-analysis was performed for fibroblast growth factor-2 (FGF-2) and Transforming growth factor-ß1 (TGF-β1) (n = 5). Results showed that use of FGF-2 significantly increased cell proliferation on day 1-(SMD = 3.56, P = 0.00), 3-(SMD = 9.04, P = 0.00), 5-(SMD = 8.37, P = 0.01), and 7 (SMD=8.51, P=0.00) than the control group. TGF-ß1 increased alkaline phosphatase (ALP) activity more than control only on day 3 (SMD = 3.68, P = 0.02). TGF-β1 had no significant effect on cell proliferation on days 1 and 3 (P > 0.05) and on ALP activity on days 5 and 7 (P > 0.05). Meta-regression analysis showed that different covariates (i.e., cell type, passage number, and growth factors' concentration) could significantly influence the effect sizes at different follow- ups (P < 0.05).

CONCLUSION

Specific growth factors might enhance the proliferation and mineralization of DSCs; however, the obtained evidence was weak. Due to the high heterogeneity among the included studies, other growth factors' inhibitory/stimulatory effects on DSCs could not be evaluated.

FGF2 drives osteosarcoma metastasis through activating FGFR1-4 receptor pathway-mediated ICAM-1 expression

Osteosarcoma is a malignant tumor with high metastatic potential, such that the overall 5-year survival rate of patients with metastatic osteosarcoma is only 20%. Therefore, it is necessary to unravel the mechanisms of osteosarcoma metastasis to identify predictors of metastasis by which to develop new therapies. Fibroblast growth factor 2 (FGF2) is a growth factor involved in embryonic development, cell migration, and proliferation. The overexpression of FGF2 and FGF receptors (FGFRs) has been shown to enhance cancer cell proliferation in lung, breast, gastric, and prostate cancers as well as melanoma. Nonetheless, the roles of FGF2 and FGFRs in human osteosarcoma cells remain unknown. In the present study, we found that FGF2 was overexpressed in human osteosarcoma sections and correlated with lung metastasis. Treatment of FGF2 induced migration activity, invasion activity, and intercellular adhesion molecule (ICAM)-1 expression in osteosarcoma cells. In particular, the downregulation or antagonism of FGFR1-4 suppressed FGF2-induced ICAM-1 expression and cancer cell migration. Furthermore, FGFR1, FGFR2, FGFR3, and FGFR4 were involved in FGF2-induced the phospholipase Cβ/protein kinase Cα/proto-oncogene c-Src signaling pathway and triggered c-Jun nuclear translocation. Subsequent c-Jun upregulation of activator protein-1 transcription activity on the ICAM-1 promoter led to an increased migration of osteosarcoma cells. Moreover, the knockdown of endogenous FGF2 suppressed ICAM-1 expression and migration of osteosarcoma cells. These findings suggest that FGF2/FGFR1-4 signaling promotes metastasis via its direct downstream target gene ICAM-1, revealing a novel potential therapeutic target for osteosarcoma.

Dental characteristics of patients with four different types of skeletal dysplasias

OBJECTIVE

Skeletal dysplasia (SD) comprises more than 450 separate disorders. We hypothesized that their dental features would be distinctive and investigated the tooth characteristics of four patients with different SDs.

MATERIAL AND METHODS

Four SD patients with molecularly confirmed diagnoses, Pt-1 acromicric dysplasia, Pt-2 hypophosphatasia and hypochondroplasia, Pt-3 cleidocranial dysplasia, and Pt-4 achondroplasia, were recruited. A tooth from each patient was evaluated for mineral density (micro-computerized tomography), surface roughness (surface profilometer), microhardness, mineral contents (energy-dispersive X-ray), and ultrastructure (scanning electron microscopy and histology), and compared with three tooth-type matched controls.

RESULTS

Pt-1 and Pt-3 had several unerupted teeth. Pt-2 had an intact-root-exfoliated tooth at 2 years old. The lingual surfaces of the patients' teeth were significantly smoother, while their buccal surfaces were rougher, than controls, except for Pt-1's buccal surface. The patients' teeth exhibited deep grooves around the enamel prisms and rough intertubular dentin. Pt-3 demonstrated a flat dentinoenamel junction and Pt-2 had an enlarged pulp, barely detectable cementum layer, and ill-defined cemento-dentinal junction. Reduced microhardnesses in enamel, dentin, and both layers were observed in Pt-3, Pt-4, and Pt-1, respectively. Pt-1 showed reduced Ca/P ratio in dentin, while both enamel and dentin of Pt-2 and Pt-3 showed reduced Ca/P ratio.

CONCLUSION

Each SD has distinctive dental characteristics with changes in surface roughness, ultrastructure, and mineral composition of dental hard tissues.

CLINICAL RELEVANCE

In this era of precision dentistry, identifying the specific potential dental problems for each patient with SD would help personalize dental management guidelines.

Oriented artificial niche provides physical-biochemical stimulations for rapid nerve regeneration

Skin wound is always accompanied with nerve damage, leading to significant sensory function loss. Currently, the functional matrix material based stem cell transplantation and in situ nerve regeneration are thought to be effective strategies, of which, how to recruit stem cells, retard senescence, and promote neural differentiation has been obstacle to be overcome. However, the therapeutic efficiency of the reported systems has yet to be improved and side effect reduced. Herein, a conduit matrix with three-dimensional ordered porous structures, regular porosity, appropriate mechanical strength, and conductive features was prepared by orienting the freezing technique, which was further filled with neural-directing exosomes to form a neural-stimulating matrix for providing hybrid physical-biochemical stimulations. This neural-stimulating matrix was then compacted with methacrylate gelatin (GelMA) hydrogel thin coat that loaded with chemokines and anti-senescence drugs, forming a multi-functional artificial niche (termed as GCr-CSL) that promotes MSCs recruitment, anti-senescence, and neural differentiation. GCr-CSL was shown to rapidly enhances in situ nerve regeneration in skin wound therapy, and with great potential in promoting sensory function recovery. This study demonstrates proof-of-concept in building a biomimetic niche to organize endogenous MSCs recruitment, differentiation, and functionalization for fast neurological and sensory recovery.

Tensin-3 is involved in osteogenic versus adipogenic fate of human bone marrow stromal cells

BACKGROUND

The tightly controlled balance between osteogenic and adipogenic differentiation of human bone marrow-derived stromal cells (BMSCs) is critical to maintain bone homeostasis. Age-related osteoporosis is characterized by low bone mass with excessive infiltration of adipose tissue in the bone marrow compartment. The shift of BMSC differentiation from osteoblasts to adipocytes could result in bone loss and adiposity.

METHODS

TNS3 gene expression during osteogenic and adipogenic differentiation of BMSCs was evaluated by qPCR and Western blot analyses. Lentiviral-mediated knockdown or overexpression of TNS3 was used to assess its function. The organization of cytoskeleton was examined by immunofluorescent staining at multiple time points. The role of TNS3 and its domain function in osteogenic differentiation were evaluated by ALP activity, calcium assay, and Alizarin Red S staining. The expression of Rho-GTP was determined using the RhoA pull-down activation assay.

RESULTS

Loss of TNS3 impaired osteogenic differentiation of BMSCs but promoted adipogenic differentiation. Conversely, TNS3 overexpression hampered adipogenesis while enhancing osteogenesis. The expression level of TNS3 determined cell shape and cytoskeletal reorganization during osteogenic differentiation. TNS3 truncation experiments revealed that for optimal osteogenesis to occur, all domains proved essential. Pull-down and immunocytochemical experiments suggested that TNS3 mediates osteogenic differentiation through RhoA.

CONCLUSIONS

Here, we identify TNS3 to be involved in BMSC fate decision. Our study links the domain structure in TNS3 to RhoA activity via actin dynamics and implicates an important role for TNS3 in regulating osteogenesis and adipogenesis from BMSCs. Furthermore, it supports the critical involvement of cytoskeletal reorganization in BMSC differentiation.

The inhibition of mineralisation by fibroblast growth factor 2 is associated with the altered expression of genes regulating phosphate balance

The study aimed to determine whether inhibitory effects of fibroblast growth factor 2 (FGF2) on mineralisation in dental pulp (DP) cultures were associated with changes in the expression of genes regulating phosphate balance (Enpp1, Ank, Slc20a2, Alpl, Phospho1, and Xpr1). DP cultures growing under mineralisation-inducing conditions were exposed to FGF2 and inhibitors of the FGFR and MEK/ERK1/2 signaling pathways. Mineralisation, culture cellularity, and gene expression were examined at various time points. Statistical analysis was performed using analysis of variance followed by the Holm-Šídák test. Control cultures exhibited transient increases in Enpp1 and Ank, continuous increases in Alpl, Phospho1, and Xpr1, and continuous decreases in Slc20a2. FGF2 increased Enpp1, Ank, and Slc20a2 and decreased Alpl, Phospho1, and Xpr1, whereas the FGF2 withdrawal and inhibition of FGFR and MEK/ERK1/2 exerted opposite effects. These changes suggest that FGF2-mediated decreases in mineralisation could be functionally coupled to the altered regulation of phosphate formation and transport.

Effects of Dental Pulp Stem Cell Preconditioning on Osteogenesis using Conditioned Media of Probiotics Bacteria

Background

Stem cells are used to treat numerous diseases; however, their lifespan is rather short. Factors such as probiotics affect and improve various cell lineage efficacies. The aim of this study was to investigate the effects of probiotics-conditioned media on dental pulp stem cell potentials in osteogenesis.

Methods

The experiment was initiated by culturing Lactobacillus casei and Lactobacillus acidophilus probiotics as well as DPS-7 cells. Bacterial supernatants were separated and concentrated as the conditioned media. The DPS-7 cells were treated with various concentrations of the conditioned media. Furthermore, MTT assay and alkaline phosphatase activity were used. The mRNA expression of three genes (bFGF, EGF-β and BMP-2) involved in osteogenesis was analyzed using a real-time polymerase chain reaction.

Results

The response of dental pulp stem cells to probiotics preconditioning promoted cell proliferation, increased alkaline phosphatase activity and upregulated bFGF and BMP-2 gene expression. Increased expression was significant for BMP-2 and moderate for bFGF; however, it was non-significant for EGF-β. The use of the two probiotics was the most effective.

Conclusion

In general, synergism of the combined probiotics preconditioning induces differentiation of DPS-7 cells into osteoblasts most effectively.

Indirect Immobilised Jagged-1 Enhances Matrisome Proteins Associated with Osteogenic Differentiation of Human Dental Pulp Stem Cells: A Proteomic Study

The indirect immobilisation of Jagged-1 (Jagged-1) promoted osteogenic differentiation of human dental pulp cells (hDPs). Furthermore, the analysis of the Reactome pathway of RNA sequencing data indicates the upregulated genes involved with the extracellular matrix (ECM). Hence, our objective was to investigate the effects of Jagged-1 on proteomic profiles of human dental pulp stem cells (hDPSC). hDPSCs were cultured on the surface coated with human IgG Fc fragment (hFc) and the surface coated with rhJagged1/Fc recombinant protein-coated surface. Cells were differentiated to the osteogenic lineage using an osteogenic differentiation medium (OM) for 14 days, and cells cultured in a growth medium were used as a control. The protein component of the cultured cells was extracted into the cytosol, membrane, nucleus, and cytoskeletal compartment. Subsequently, the proteomic analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS). Metascape gene list analysis reported that Jagged-1 stimulated the expression of the membrane trafficking protein (DOP1B), which can indirectly improve osteogenic differentiation. hDPSCs cultured on Jagged-1 surface under OM condition expressed COL27A1, MXRA5, COL7A1, and MMP16, which played an important role in osteogenic differentiation. Furthermore, common matrisome proteins of all cellular components were related to osteogenesis/osteogenic differentiation. Additionally, the gene ontology categorised by the biological process of cytosol, membrane, and cytoskeleton compartments was associated with the biomineralisation process. The gene ontology of different culture conditions in each cellular component showed several unique gene ontologies. Remarkably, the Jagged-1_OM culture condition showed the biological process related to odontogenesis in the membrane compartment. In conclusion, the Jagged-1 induces osteogenic differentiation could, mainly through the regulation of protein in the membrane compartment.

6-Bromoindirubin-3′-Oxime Regulates Colony Formation, Apoptosis, and Odonto/Osteogenic Differentiation in Human Dental Pulp Stem Cells

6-bromoindirubin-3′-oxime (BIO) is a candidate small molecule that effectively modulates Wnt signalling owing to its stable property. The present study investigated the influence of BIO on the odonto/osteogenic differentiation of human dental pulp stem cells (hDPSCs). hDPSCs were treated with 200, 400, or 800 nM BIO, and the effects on hDPSC responses and osteogenic differentiation were assessed. BIO-mediated Wnt activation was confirmed by β-catenin nuclear translocation detected by immunofluorescence staining. BIO attenuated colony formation and cell migration determined by in vitro wound-healing assay. BIO increased early apoptotic cell population evaluated using flow cytometry. For osteogenic induction, BIO promoted alkaline phosphatase (ALP) activity and mineralisation in a dose-dependent manner. ALP, RUNX2, OCN, OSX, ANKH, DMP1, and DSPP mRNA expression were significantly upregulated. The OPG/RANKL expression ratio was also increased. Further, BIO attenuated adipogenic differentiation as demonstrated by decreased lipid accumulation and adipogenic-related gene expression. Bioinformatic analysis of RNA sequencing data from the BIO-treated hDPSCs revealed that BIO modulated pathways related to autophagy and actin cytoskeleton regulation. These findings demonstrated that BIO treatment promoted hDPSC osteogenic differentiation. Therefore, this small molecule is a strong candidate as a bioactive molecule to enhance dentin repair.

Study of Alveolar Bone Remodeling Using Deciduous Tooth Stem Cells and Hydroxyapatite by Vascular Endothelial Growth Factor Enhancement and Inhibition of Matrix Metalloproteinase-8 Expression in vivo

Background

Periodontitis progression is characterized by alveolar bone loss, and its prevention is a major clinical problem in periodontal disease management. Matrix metalloproteinase-8 (MMP-8) has been shown to adequately monitor the treatment of chronic periodontitis patients as gingival crevicular fluid MMP-8s were positively associated with the severity of periodontal disease. Moreover, modulating the vascular endothelial growth factor (VEGF) levels in bones could be a good way to improve bone regeneration and cure periodontitis as VEGF promotes endothelial cell proliferation, proteolytic enzyme release, chemotaxis, and migration; all of which are required for angiogenesis.

Purpose

The aim of this study was to determine the effect of hydroxyapatite incorporated with stem cells from exfoliated deciduous teeth (SHED) in Wistar rats’ initial alveolar bone remodeling based on the findings of MMP-8 and VEGF expressions.

Methods

A hydroxyapatite scaffold (HAS) in conjunction with SHED was transplanted into animal models with alveolar mandibular defects. A total of 10 Wistar rats (Rattus norvegicus) were divided into two groups: HAS and HAS + SHED. Immunohistochemistry staining was performed after 7 days to facilitate the examination of MMP-8 and VEGF expressions.

Results

The independent t-test found significant downregulation of MMP-8 and upregulation VEGF expressions in groups transplanted with HAS in conjunction with SHED compared with the HAS group (p < 0.05).

Conclusion

The combination of SHED with HAS on alveolar bone defects may contribute to initial alveolar bone remodeling as evident through the assessments of MMP-8 and VEGF expressions.

Basic fibroblast growth factor inhibits aortic valvular interstitial cells calcification via Notch1 pathway

Calcific aortic valve disease (CAVD) is an active pathological process mediated by abnormal activation and transdifferentiation of valvular interstitial cells (VICs). The present study aims to investigate the function and underlying mechanism of the basic fibroblast growth factor (BFGF) on osteogenic differentiation of VICs. Porcine VICs cultured with osteogenic induction medium are supplemented with or without BFGF. Morphology of VICs is identified by fluorescein isothiocyanate-labeled phalloidin, the cell viability is assessed by the cell counting kit-8 method, and protein and mRNA expression level of osteogenic differentiation markers, including Runx2, osteopontin, and Sp7, are verified by western blot analysis and quantitative real-time PCR, respectively. RNA sequencing is used to identify changes in gene profiles. Alizarin Red S staining is used to measure calcium deposition. The results demonstrate that the content of calcium deposition and the expression level of osteogenic markers are downregulated by supplementing BFGF. Notch1 signaling pathway is extracted as a candidate target after bioinformatics analysis by RNA sequencing. The transfection of si-Notch1 abolishes the calcification inhibitory effect of BFGF. Taken together, our findings shed the light on the mechanism and potential therapeutics of BFGF for CAVD.

Injectable eggshell-derived hydroxyapatite-incorporated fibroin-alginate composite hydrogel for bone tissue engineering

Tissue engineering is a promising approach to repair and regenerate damaged or lost tissues or organs. In dental aspect, reconstruction of the resorbed alveolar bone after tooth extraction plays an important role in the success of dental substitution, especially in dental implant treatment. The hydroxyapatite (HA)-incorporated fibroin-alginate composite injectable hydrogel was fabricated to be used as scaffold for bone regeneration. HA was synthesized from eggshell biowaste. Fibroin was extracted from Bombyx mori cocoon. The synthesized HA, fibroin and alginate hydrogel were characterized. HA-incorporated fibroin-alginate hydrogel had decreased pore size and porosity compared with pure alginate hydrogel. Thermal analysis showed that hydrogel had a degradation peak of approximately 250 °C. Hydrogel could absorb water, with a swelling ratio of around 300% at 24 h. Hydrogel was degraded as time passed and almost completely degraded at day 7. Its compressive Young's modulus was approximately 0.04 ± 0.02 N/mm² to 0.10 ± 0.02 N/mm². Primary cytotoxicity test indicated non-toxic potential of the fabricated hydrogel. Increased ALP activity was observed in MC3T3-E1 cultured in HA-incorporated fibroin-alginate hydrogel. Results suggested the potential use of injectable HA fibroin-alginate hydrogel as dental scaffolding material. Further studies including in vivo examinations are needed prior to its clinical application.

Parathyroid Hormone 1 Receptor Signaling in Dental Mesenchymal Stem Cells: Basic and Clinical Implications

Parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) are two peptides that regulate mineral ion homeostasis, skeletal development, and bone turnover by activating parathyroid hormone 1 receptor (PTH1R). PTH1R signaling is of profound clinical interest for its potential to stimulate bone formation and regeneration. Recent pre-clinical animal studies and clinical trials have investigated the effects of PTH and PTHrP analogs in the orofacial region. Dental mesenchymal stem cells (MSCs) are targets of PTH1R signaling and have long been known as major factors in tissue repair and regeneration. Previous studies have begun to reveal important roles for PTH1R signaling in modulating the proliferation and differentiation of MSCs in the orofacial region. A better understanding of the molecular networks and underlying mechanisms for modulating MSCs in dental diseases will pave the way for the therapeutic applications of PTH and PTHrP in the future. Here we review recent studies involving dental MSCs, focusing on relationships with PTH1R. We also summarize recent basic and clinical observations of PTH and PTHrP treatment to help understand their use in MSCs-based dental and bone regeneration.

Dorsomorphin attenuates Jagged1-induced mineralization in human dental pulp cells

AIM

To investigate whether TGF-β/BMP signalling participates in Jagged1-induced osteogenic differentiation in human dental pulp cells (hDPs).

METHODOLOGY

Bioinformatic analysis of publicly available RNA sequencing data of Jagged1-treated hDPs was performed using NetworkAnalyst. The mRNA expression was validated using real-time polymerase chain reaction. hDPs were seeded on Jagged1 immobilized surfaces in the presence or absence of TGF-β or BMP inhibitor. Osteogenic differentiation was evaluated using alkaline phosphatase staining, osteogenic marker gene expression and mineralization assay. Statistical analyses were performed using a Kruskal-Wallis test, followed by a pairwise comparison for more than three group comparison. Mann-Whitney U-test was employed for two group comparison. The statistical significance was considered at p < .05.

RESULTS

Jagged1 treatment in growth medium significantly promoted TGFB1, TGFB2 and TGFB3 whilst significantly inhibited BMP2, BMP4 and BMP6 mRNA expression (p < .05). In osteogenic induction medium, Jagged1 significantly up-regulated TGFB1, TGFB2 and TGFB3 at days 1 and 3 (p < .05). Pre-treatment with TGF-β1, TGF-β2 or TGF-β3 prior to osteogenic induction resulted in the significant increase of osteogenic marker gene expression, collagen type 1 protein expression, alkaline phosphatase enzymatic activity and mineral deposition (p < .05). However, TGF-β signalling inhibition with SB431542 (4 μmol L^-1 ) or SB505124 (47 and 129 nmol L^-1 ) failed to attenuate the effect of Jagged1-induced osteogenic differentiation in hDPs. Dorsomorphin (4 and 8 μmol L^-1 ) treatment significantly abolished the effect of Jagged1 on mineralization by hDPs (p < .05).

CONCLUSION

Notch signalling activation by Jagged1 modulated TGF-β and BMP ligand expression. Dorsomorphin, but not TGF-β receptor inhibitor, attenuated Jagged1-induced osteogenic differentiation in hDPs.

The Regenerative Potential of bFGF in Dental Pulp Repair and Regeneration

Regenerative endodontic therapy intends to induce the host’s natural wound-healing process, which can restore the vitality, immunity, and sensitivity of the inflammatory or necrotic pulp tissue destroyed by infection or trauma. Myriads of growth factors are critical in the processes of pulp repair and regeneration. Among the key regulatory factors are the fibroblast growth factors, which have turned out to be the master regulators of both organogenesis and tissue homeostasis. Fibroblast growth factors, a family composed of 22 polypeptides, have been used in tissue repair and regeneration settings, in conditions as diverse as burns, ulcers, bone-related diseases, and spinal cord injuries. Meanwhile, in dentistry, the basic fibroblast growth factor is the most frequently investigated. Thereby, the aim of this review is 2-fold: 1) foremost, to explore the underlying mechanisms of the bFGF in dental pulp repair and regeneration and 2) in addition, to shed light on the potential therapeutic strategies of the bFGF in dental pulp–related clinical applications.

Sinking Our Teeth in Getting Dental Stem Cells to Clinics for Bone Regeneration

Dental stem cells have been isolated from the medical waste of various dental tissues. They have been characterized by numerous markers, which are evaluated herein and differentiated into multiple cell types. They can also be used to generate cell lines and iPSCs for long-term in vitro research. Methods for utilizing these stem cells including cellular systems such as organoids or cell sheets, cell-free systems such as exosomes, and scaffold-based approaches with and without drug release concepts are reported in this review and presented with new pictures for clarification. These in vitro applications can be deployed in disease modeling and subsequent pharmaceutical research and also pave the way for tissue regeneration. The main focus herein is on the potential of dental stem cells for hard tissue regeneration, especially bone, by evaluating their potential for osteogenesis and angiogenesis, and the regulation of these two processes by growth factors and environmental stimulators. Current in vitro and in vivo publications show numerous benefits of using dental stem cells for research purposes and hard tissue regeneration. However, only a few clinical trials currently exist. The goal of this review is to pinpoint this imbalance and encourage scientists to pick up this research and proceed one step further to translation.

Interleukin 15 participates in Jagged1-induced mineralization in human dental pulp cells

OBJECTIVES

Crosstalk between Notch and other cell signaling molecules has been implicated to regulate the osteogenic differentiation. Understanding the interaction between Notch and IL15 is essential to reveal molecular mechanism. Thus, the objective of the present study was to investigate whether IL15 participates in the Notch signaling-induced mineral deposition in human dental pulp cells (hDPs).

METHODS

hDPs were explanted from dental pulp tissues. To activate Notch signaling, the cells were seeded on Jagged1-immobilized surfaces. The mRNA expression was evaluated using real-time polymerase chain reaction. hDPs were treated with 5-50 ng/mL IL15. Cell viability and proliferation were determined using an MTT assay. Mineral deposition was examined using alizarin red s and Von Kossa staining. In some experiments, the cells were pretreated with a JAK inhibitor prior to stimulation.

RESULTS

Jagged1 induced IL15 and IL15RA expression in hDPs. IL15 treatment significantly increased mineral deposition at 14 d and upregulated ALP, OCN, OSX, ANKH, and ENPP1 mRNA expression. IL15-induced mineralization was attenuated by JAK inhibitor pretreatment. Further, JAK inhibitor pretreatment inhibited the effect of Jagged1 on hDP mineral deposition.

CONCLUSION

IL15 promoted the osteogenic differentiation in hDPs. Moreover, IL15 participated in the Jagged1-induced mineralization in hDPs.

Activation of nuclear factor-kappa B by TNF promotes nucleus pulposus mineralization through inhibition of ANKH and ENPP1

Spontaneous mineralization of the nucleus pulposus (NP) has been observed in cases of intervertebral disc degeneration (IDD). Inflammatory cytokines have been implicated in mineralization of multiple tissues through their modulation of expression of factors that enable or inhibit mineralization, including TNAP, ANKH or ENPP1. This study examines the underlying factors leading to NP mineralization, focusing on the contribution of the inflammatory cytokine, TNF, to this pathologic event. We show that human and bovine primary NP cells express high levels of ANKH and ENPP1, and low or undetectable levels of TNAP. Bovine NPs transduced to express TNAP were capable of matrix mineralization, which was further enhanced by ANKH knockdown. TNF treatment or overexpression promoted a greater increase in mineralization of TNAP-expressing cells by downregulating the expression of ANKH and ENPP1 via NF-κB activation. The increased mineralization was accompanied by phenotypic changes that resemble chondrocyte hypertrophy, including increased RUNX2 and COL10A1 mRNA; mirroring the cellular alterations typical of samples from IDD patients. Disc organ explants injected with TNAP/TNF- or TNAP/shANKH-overexpressing cells showed increased mineral content inside the NP. Together, our results confirm interactions between TNF and downstream regulators of matrix mineralization in NP cells, providing evidence to suggest their participation in NP calcification during IDD.

Effect of fibronectin, FGF-2, and BMP4 in the stemness maintenance of BMSCs and the metabolic and proteomic cues involved

Background

Growing evidence suggests that the pluripotent state of mesenchymal stem cells (MSCs) relies on specific local microenvironmental cues such as adhesion molecules and growth factors. Fibronectin (FN), fibroblast growth factor 2 (FGF2), and bone morphogenetic protein 4 (BMP4) are the key players in the regulation of stemness and lineage commitment of MSCs. Therefore, this study was designed to investigate the pluripotency and multilineage differentiation of bone marrow-derived MSCs (BMSCs) with the introduction of FN, FGF-2, and BMP4 and to identify the metabolic and proteomic cues involved in stemness maintenance.

Methods

To elucidate the stemness of BMSCs when treated with FN, FGF-2, and BMP4, the pluripotency markers of OCT4, SOX2, and c-MYC in BMSCs were monitored by real-time PCR and/or western blot. The nuclear translocation of OCT4, SOX2, and c-MYC was investigated by immunofluorescence staining. Multilineage differentiation of the treated BMSCs was determined by relevant differentiation markers. To identify the molecular signatures of BMSC stemness, gas chromatography-mass spectrometry (GC-MS), liquid chromatography-tandem mass spectrometry (LC-MS/MS), and bioinformatics analysis were utilized to determine the metabolite and protein profiles associated with stem cell maintenance.

Results

Our results demonstrated that the expression of stemness markers decreased with BMSC passaging, and the manipulation of the microenvironment with fibronectin and growth factors (FGF2 and BMP4) can significantly improve BMSC stemness. Of note, we revealed 7 differentially expressed metabolites, the target genes of these metabolites may have important implications in the maintenance of BMSCs through their effects on metabolic activity, energy production, and potentially protein production. We also identified 21 differentially abundant proteins, which involved in multiple pathways, including metabolic, autophagy-related, and signaling pathways regulating the pluripotency of stem cells. Additionally, bioinformatics analysis comfirned the correlation between metabolic and proteomic profiling, suggesting that the importance of metabolism and proteome networks and their reciprocal communication in the preservation of stemness.

Conclusions

These results indicate that the culture environment supplemented with the culture cocktail (FN, FGF2, and BMP4) plays an essential role in shaping the pluripotent state of BMSCs. Both the metabolism and proteome networks are involved in this process and the modulation of cell-fate decision making. All these findings may contribute to the application of MSCs for regenerative medicine.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02227-7.

Promoting Effect of Basic Fibroblast Growth Factor in Synovial Mesenchymal Stem Cell-Based Cartilage Regeneration

Synovial mesenchymal stem cell (SMSC) is the promising cell source of cartilage regeneration but has several issues to overcome such as limited cell proliferation and heterogeneity of cartilage regeneration ability. Previous reports demonstrated that basic fibroblast growth factor (bFGF) can promote proliferation and cartilage differentiation potential of MSCs in vitro, although no reports show its beneficial effect in vivo. The purpose of this study is to investigate the promoting effect of bFGF on cartilage regeneration using human SMSC in vivo. SMSCs were cultured with or without bFGF in a growth medium, and 2 × 10⁵ cells were aggregated to form a synovial pellet. Synovial pellets were implanted into osteochondral defects induced in the femoral trochlea of severe combined immunodeficient mice, and histological evaluation was performed after eight weeks. The presence of implanted SMSCs was confirmed by the observation of human vimentin immunostaining-positive cells. Interestingly, broad lacunae structures and cartilage substrate stained by Safranin-O were observed only in the bFGF (+) group. The bFGF (+) group had significantly higher O’Driscoll scores in the cartilage repair than the bFGF (−) group. The addition of bFGF to SMSC growth culture may be a useful treatment option to promote cartilage regeneration in vivo.

Transcriptome analysis of basic fibroblast growth factor treated stem cells isolated from human exfoliated deciduous teeth

Background

Basic fibroblast growth factor (bFGF) regulates cell proliferation, migration, and differentiation in various cell types. The aim of the present study was to determine the bFGF target genes in stem cells isolated from human exfoliated deciduous teeth (SHEDs).

Methods

Cells were isolated from pulp tissue obtained from exfoliated deciduous teeth. Mesenchymal stem cell surface markers and the differentiation potential toward adipogenic and neurogenic lineages were characterized. The bFGF-treated SHED transcriptome was examined using a high throughput RNA sequencing technique. The mRNA and protein expression of selected genes were evaluated using real-time polymerase chain reaction and immunofluorescence staining, respectively. Cell cycle analysis was performed by flow cytometry. The colony forming unit number was also examined.

Results

The isolated cells expressed CD44, CD90, CD105, but not CD45. The upregulation of adipogenic and neurogenic marker genes was observed after culturing cells in the appropriate induction medium. Transcriptome analysis of the bFGF treated cells revealed that the upregulated genes were in the cell cycle related pathways, while the downregulated genes were in the extracellular matrix related pathways. Correspondingly, bFGF induced MKI67 mRNA expression and Ki67 protein expression. Furthermore, bFGF treatment significantly decreased the G0/G1, but increased the G2/M, population in SHEDs. Colony formation was markedly increased in the bFGF treated group and was attenuated by pretreating the cells with FGFR or PI3K inhibitors.

Conclusion

bFGF controls cell cycle progression in SHEDs. Thus, it can be used to amplify cell number to obtain the amount of cells required for regenerative treatments.

Multi-lineage differentiation and clinical application of stem cells from exfoliated deciduous teeth

Stem cells from human exfoliated deciduous teeth (SHED) have now been considered one of the most promising sources of stem cells for tissue engineering and stem cell therapies due to their stemness and potential to differentiate into other cell lines. The high proliferation rate, the differentiation capacity, the easy access and less ethical concerns make SHED a brilliant solution for many diseases. The purpose of this review is to describe current knowledge of SHED's capability of differentiation, applications and immune status and to draw attention to further research on the mechanism and the dependability of stem cell therapy with SHED.

Diabetes, Diabetic Complications, and Phosphate Toxicity: A Scoping Review

This article presents a scoping review and synthesis of research findings investigating the toxic cellular accumulation of dysregulated inorganic phosphate-phosphate toxicity-as a pathophysiological determinant of diabetes and diabetic complications. Phosphorus, an essential micronutrient, is closely linked to the cellular metabolism of glucose for energy production, and serum inorganic phosphate is often transported into cells along with glucose during insulin therapy. Mitochondrial dysfunction and apoptosis, endoplasmic reticulum stress, neuronal degeneration, and pancreatic cancer are associated with dysregulated levels of phosphate in diabetes. Ectopic calcification involving deposition of calcium-phosphate crystals is prevalent throughout diabetic complications, including vascular calcification, nephropathy, retinopathy, and bone disorders. A low-glycemic, low-phosphate dietary intervention is proposed for further investigations in the treatment and prevention of diabetes and related diabetic pathologies.

Effect of Jagged1 on the expression of genes in regulation of osteoblast differentiation and bone mineralization ontology in human dental pulp and periodontal ligament cells

Objective

To define the effect of Jagged1 on the gene expression in osteoblast differentiation, regulation of osteoblast differentiation and regulation of bone mineralization ontology.

Methods

Human dental pulp and periodontal ligament cells were isolated using explant method. Cells were seeded on Jagged1 immobilized surface. The mRNA expression was determined using real-time polymerase chain reaction. Mineral deposition was evaluated using alizarin red s staining. Publicly available database of gene expression profiles (GSE126249 and GSE94989) were downloaded and performed bioinformatic analysis to identify gene expression in osteoblast differentiation and regulation of osteoblast differentiation and mineralization ontology.

Results

Both human dental pulp cells and human periodontal ligament cells expressed higher Notch target gene (HES1 and HEY1) when cells were seeded on Jagged1 immobilization surface. Jagged1 significantly increased an in vitro mineral deposition in both cell types after maintaining in osteogenic induction medium for 14 days. Correspondingly, the significant increase of ALPL mRNA expression was observed, while there was no significant change in ANKH and ENPP1 mRNA expression in Jagged1 treated condition. From bioinformatic analysis of genes in osteoblast differentiation ontology, IARS, COL1A1, ALPL, COL6A1, CREB3L1, and SNAI2 mRNA levels were upregulated while GJA1 mRNA levels were decreased upon Jagged1 exposure. In the regulation of bone mineralization ontology, evidences supported that TFGB1 and TGFB3 were upregulated in Jagged1 treated condition.

Conclusion

Jagged1 promote the mRNA expression of several genes in osteoblast differentiation related gene ontology. This could be further employed to identify the mechanism by which Jagged1 promoted osteogenic differentiation in human dental pulp and periodontal ligament cells.