Multipotent Differentiation of Human Dental Pulp Stem Cells: a Literature Review

Altered Methylation Levels in LINE-1 in Dental Pulp Stem Cell-Derived Osteoblasts

OBJECTIVES

Long interspersed nuclear element-1 (LINE-1) and Alu elements are major targets of methylation, an epigenetic mechanism that is associated with several biological processes. Alterations of methylation of LINE-1 and Alu have been reported in cancers, diseases, and ageing. However, these alterations have not been studied in osteogenic differentiation of dental pulp stem cells (DPSCs), which are a promising source of tissue regeneration.

METHOD

This study was performed to investigate the methylation level of LINE-1 and Alu in dental pulp stem cell-derived osteoblasts (DPSC-DOs). By using the combined bisulfite restriction analysis, the levels of total methylation and 4 patterns of methylated cytosine-phosphate-guanine (CpG) dinucleotides of LINE-1 and Alu were compared between DPSC-DOs and DPSCs.

RESULT

The levels of total methylation and hypermethylated CpG dinucleotides of LINE-1 were significantly lower (P = .015 and .021, respectively), whilst levels of one pattern of partial methylated CpG dinucleotides were significantly higher in DPSC-DOs than DPSCs (P = .021). The methylation of Alu was not significantly different between DPSCs and DPSC-DOs.

CONCLUSIONS

Methylation alterations of LINE-1 but not Alu were found in osteogenic differentiation of DPSCs. The results of this study offer foundational insights into osteoblast differentiation from an epigenetic perspective and may contribute to advancements in bone regeneration therapy in the future.

Current and future state of the management of Hirschsprung disease

The enteric nervous system (ENS) consists of a network of neurons and glia that control numerous complex functions of the gastrointestinal tract. Hirschsprung disease (HSCR) is a congenital disorder characterized by the absence of ENS along variable lengths of distal intestine due to failure of neural crest-derived cells to colonize the distal intestine during embryonic development. A patient with HSCR usually presents with severe constipation in the neonatal period and is diagnosed by rectal suction biopsy, followed by pull-through procedure to surgically remove the affected segment and reconnect the proximal ganglionated intestine to the anus. Outcomes after pull-through surgery are suboptimal and many patients suffer from ongoing issues of dysmotility and bowel dysfunction, suggesting there is room for optimizing the management of this disease. This review focuses on discussing the recent advances to better understand HSCR and leverage them for more accurate and potentially less invasive diagnosis. We also discuss the potential future management of HSCR, particularly cell-based approaches for the treatment of HSCR.

Dentin sialoprotein promotes endothelial differentiation of dental pulp stem cells through DSPaa34-50-endoglin-AKT1 axis

Dentin sialoprotein (DSP), a major dentin extracellular matrix noncollagenous protein, is well recognized as an important regulator for dentinogenesis. DSP as a secreted protein can interact with membrane receptors, activate intracellular signaling, and initiate the odontoblastic differentiation of dental papilla cells. In a recent study, we have demonstrated that DSP can induce the endothelial differentiation of dental pulp stem cells (DPSCs), a type of tooth pulp-derived multipotent stem cells, dependent on membrane receptor endoglin (ENG). However, the intimate mechanisms by which DSP-ENG association facilitates the endothelial differentiation of DPSCs remain enigmatic. Here, we find that the amino acid (aa) residues 34-50 of DSP (DSPaa34-50) is responsible for its association with ENG using a series of co-immunoprecipitation assays. Immunofluorescent staining and in situ proximity ligation assay demonstrate that overexpressed ENG in human embryonic kidney 293T cells shows codistribution and proximity ligation assay signals to the supplemented DSPaa34-50 protein but not to DSP without aa34-50 (DSPΔ34-50) on cell surfaces. Moreover, the zona pellucida domain of ENG mediates its association with DSPaa34-50. Further experiments indicate that DSPaa34-50 exhibits equivalent effects to the full-length DSP on the migration and endothelial differentiation of DPSCs dependent on ENG but DSPΔ34-50 does not. Mechanistically, DSPaa34-50 activates AKT1 and triggers the expression of blood vessel development-related genes in DPSCs. Multiple experiments demonstrate that AKT1 inhibition suppresses the DSPaa34-50-induced migration and endothelial differentiation of DPSCs. Thus, AKT1 mediates the cellular and molecular functions of DSPaa34-50-ENG association. Collectively, these findings identify that DSP promotes the endothelial differentiation of DPSCs through the DSPaa34-50-ENG-AKT1 signaling axis.

The Multifaceted Roles of BACH1 in Disease: Implications for Biological Functions and Therapeutic Applications

BTB domain and CNC homolog 1 (BACH1) belongs to the family of basic leucine zipper proteins and is expressed in most mammalian tissues. It can regulate its own expression and play a role in transcriptionally activating or inhibiting downstream target genes. It has a crucial role in various biological processes, such as oxidative stress, cell cycle, heme homeostasis, and immune regulation. Recent research highlights BACH1's significant regulatory roles in a series of conditions, including stem cell pluripotency maintenance and differentiation, growth, senescence, and apoptosis. BACH1 is closely associated with cardiovascular diseases and contributes to angiogenesis, atherosclerosis, restenosis, pathological cardiac hypertrophy, myocardial infarction, and ischemia/reperfusion (I/R) injury. BACH1 promotes tumor cell proliferation and metastasis by altering tumor metabolism and the epithelial-mesenchymal transition phenotype. Moreover, BACH1 appears to show an adverse role in diseases such as neurodegenerative diseases, gastrointestinal disorders, leukemia, pulmonary fibrosis, and skin diseases. Inhibiting BACH1 may be beneficial for treating these diseases. This review summarizes the role of BACH1 and its regulatory mechanism in different cell types and diseases, proposing that precise targeted intervention of BACH1 may provide new strategies for human disease prevention and treatment.

Molecular Biological Comparison of Pulp Stem Cells from Supernumerary Teeth, Permanent Teeth, and Deciduous Teeth for Endodontic Regeneration

Supernumerary tooth-derived pulp stem cells (SNTSCs) hold promise for endodontic regeneration, yet little is known about the similarities and diversities of SNTSCs relative to other dental-derived mesenchymal stem cells. Herein, we compare the biological characteristics of SNTSCs with dental pulp stem cells (DPSCs) and stem cells from human exfoliated deciduous teeth (SHED). Cell proliferation, migration, and odontogenic differentiation potential, as well as viability and aging-related phenotype after long-term storage, were evaluated. Additionally, gene expressions during induced odontogenic differentiation were profiled by transcriptome sequencing. Our findings indicated that the SNTSCs outperformed the DPSCs but were inferior to the SHED in cell proliferation. The SNTSCs exhibited comparable migratory capacity to the SHED and surpassed the DPSCs. Of particular interest, the odontogenic differentiation potential followed the pattern of SHED > SNTSCs > DPSCs. After two years of storage, the SNTSCs showed weakness in resistance to apoptosis induced by lipopolysaccharide, whereas difference between the SNTSCs and SHED in stemness and senescence was not obvious. Transcriptome analysis revealed that upregulated genes in the SNTSCs were particularly enriched in inflammatory signaling pathways compared to both the DPSCs and SHED. Collectively, SNTSCs share many satisfactory features in proliferation and differentiation with SHED, which may serve as a promising alternative cell source for endodontic regeneration.

The effect of human umbilical cord mesenchymal stem cells combined with concentrated growth factor on repairing necrotic pulp caused by dental caries

This study investigated the impact of combining human umbilical cord mesenchymal stem cells (hUC-MSCs) with concentrated growth factor (CGF) on regenerating necrotic pulp. Ten-month-old male Bama miniature pigs were divided into control and caries groups. The experimental teeth were randomly divided into three groups: caries untreated, Ca(OH)2, and engineering dental pulp-like tissue (EDPT). hUC-MSCs and CGF scaffold were combined to construct EDPT, and the histological structure was observed. Odontoblasts and dental pulp cells were counted in each group. The results showed that hUC-MSCs adhered firmly to the porous mesh CGF scaffold, grew vigorously, and stretched sufficiently. In the EDPT group, odontoblasts in the root canal were arranged neatly, and predentin was formed. The odontoblast and dental pulp cell counts in the EDPT group were statistically significant compared to the caries untreated and Ca(OH)2 groups. The hUC-MSCs-CGF could successfully repair necrotic pulp in animals with dental caries.

Harmine promotes odontoblastic differentiation of dental pulp stem cells

INTRODUCTION

Dental pulp stem cells (DPSCs) have the potential to differentiate into various types of tissues including tooth, adipose, cartilage, muscle, nerve, and also possess regenerative properties. Harmine, a beta-carboline alkaloid, has been shown to have antitumor activities and promote bone formation through the differentiation of osteoblasts. The aim of this study was to investigate the effect of harmine on the differentiation of DPSCs into odontoblast cells.

MATERIALS AND METHODS

DPSCs were obtained from Iran's National Genetic Reserve Center and cultured under standard stem cell culture conditions. The cells were differentiated in culture medium with and without harmine, and cell viability was evaluated using MTT assay at different harmine concentrations. Moreover, differentiation of cells was measured using Alizarin Red staining, and the expression of Runx2, DSPP, and DMP1 genes was evaluated using western blotting and real-time PCR.

RESULTS

Harmine increased the survival rate of DPSCs in a time--dependent manner, but higher doses (above 80 μM) had a toxic effect. On day 14, Alizarin Red staining showed increased differentiation of odontoblasts in the harmine-treated groups compared to the untreated groups. Furthermore, harmine increased the expression of Runx2, DSPP, and DMP1 genes and proteins.

CONCLUSION

These findings suggest that harmine has a significant impact on the differentiation and proliferation of odontoblasts in DPSCs, likely due to its various properties and role in healing various diseases. Therefore, harmine could serve as a potential therapeutic agent for promoting dental tissue regeneration using DPSCs.

Human dental pulp stem cells modulate pro-inflammatory macrophages both through cell-to-cell contact and paracrine signaling

Introduction

Macrophages play a key role in most of the inflammatory diseases such as Rheumatoid Arthritis (RA), but the mechanism underlying their pathogenesis is still under study. Among stem cells, human dental pulp stem cells (hDPSCs) have attracted attention due to their easy accessibility and immunomodulatory properties, making them a promising adjuvant therapy. In this study, we aimed to evaluate the capacity of hDPSCs to modulate the phenotypes of primary human macrophages. Additionally, we sought to observe the differences induced on macrophages when cultured directly with hDPSCs or through a cell culture insert, mimicking the paracrine communication pathway.

Methods

Monocytes, isolated from buffy coats, were differentiated into pro-inflammatory M1 and anti-inflammatory M2 macrophages. Subsequently, they were cultured with hDPSCs either directly or via a cell-culture insert for 48 hours. Finally, they were analyzed for protein, gene expression, cytokines levels and immunofluorescence.

Results

In our study, we have demonstrated that, hDPSCs, even without priming, can reduce TNFα levels and enhancing IL-10 release in pro-inflammatory macrophages, both through direct contact and paracrine signaling. Furthermore, we found that their effects are more pronounced when in cell-to-cell contact through the decrease of NF-kB and COX-2 expression and of CD80/PD-L1 colocalization. HDPSCs, when in contact with macrophages, showed enhanced expression of NF-kB, COX-2, ICAM-1, PD-L1, FAS-L, TNFα and IFNγ.

Conclusion

We showed that hDPSCs exert immunomodulatory effects on pro-inflammatory macrophages, with cell-to-cell contact yielding a more pronounced outcome compared to paracrine signaling. Our work highlights the immunomodulatory properties of hDPSCs on activated pro-inflammatory macrophages and the potential therapeutic role in inflamed tissue.

Sphingolipidomic profiling of human Dental Pulp Stem Cells undergoing osteogenic differentiation

It is now recognized that sphingolipids are involved in the regulation and pathophysiology of several cellular processes such as proliferation, migration, and survival. Growing evidence also implicates them in regulating the behaviour of stem cells, the use of which is increasingly finding application in regenerative medicine. A shotgun lipidomic study was undertaken to determine whether sphingolipid biomarkers exist that can regulate the proliferation and osteogenic differentiation of human Dental Pulp Stem Cells (hDPSCs). Sphingolipids were extracted and identified by direct infusion into an electrospray mass spectrometer. By using cells cultured in osteogenic medium and in medium free of osteogenic stimuli, as a control, we analyzed and compared the SPLs profiles. Both cellular systems were treated at different times (72 hours, 7 days, and 14 days) to highlight any changes in the sphingolipidomic profiles in the subsequent phases of the differentiation process. Signals from sphingolipid species demonstrating clear differences were selected, their relative abundance was determined, and statistical differences were analyzed. Thus, our work suggests a connection between sphingolipid metabolism and hDPSC osteogenic differentiation and provides new biomarkers for improving hDPSC-based orthopaedic regenerative medicine.

Chios gum mastic enhance the proliferation and odontogenic differentiation of human dental pulp stem cells

Dental pulp stem cells (DPSCs) are a type of adult stem cell present in the dental pulp tissue. They possess a higher proliferative capacity than bone marrow mesenchymal stem cells. Their ease of collection from patients makes them well-suited for tissue engineering applications, such as tooth and nerve regeneration. Chios gum mastic (CGM), a resin extracted from the stems and leaves of Pistacia lentiscus var. Chia, has garnered attention for its potential in tissue regeneration. This study aims to confirm alterations in cell proliferation rates and induce differentiation in human DPSCs (hDPSCs) through CGM treatment, a substance known for effectively promoting odontogenic differentiation. Administration of CGM to hDPSC cells was followed by an assessment of cell survival, proliferation, and odontogenic differentiation through protein and gene analysis. The study revealed that hDPSCs exhibited low sensitivity to CGM toxicity. CGM treatment induced cell proliferation by activating cell-cycle proteins through the Wnt/β-catenin pathway. Additionally, the study demonstrated that CGM enhances alkaline phosphatase activation by upregulating the expression of collagen type I, a representative matrix protein of dentin. This activation of markers associated with odontogenic and bone differentiation ultimately facilitated the mineralization of hDPSCs. This study concludes that CGM, as a natural substance, fosters the cell cycle and cell proliferation in hDPSCs. Furthermore, it triggers the transcription of odontogenic and osteogenic markers, thereby facilitating odontogenic differentiation.

Dental pulp stem cells-derived cannabidiol-treated organoid-like microspheroids show robust osteogenic potential via upregulation of WNT6

Dental pulp stem cells (DPSC) have shown osteogenic and bone regenerative potential. Improving the in situ bone regeneration potential of DPSC is crucial for their application as seed cells during bone defect reconstruction in clinics. This study aimed to develop DPSC-derived organoid-like microspheroids as effective seeds for bone tissue engineering applications. DPSC osteogenic microspheroids (70 μm diameter) were cultured in a polydimethylsiloxane-mold-based agarose-gel microwell-culture-system with or without cannabidiol (CBD)-treatment. Results of in vitro studies showed higher osteogenic differentiation potential of microspheroids compared with 2D-cultured-DPSC. CBD treatment further improved the osteogenic differentiation potential of microspheroids. The effect of CBD treatment in the osteogenic differentiation of microspheroids was more pronounced compared with that of CBD-treated 2D-cultured-DPSC. Microspheroids showed a higher degree of bone regeneration in nude mice calvarial bone defect compared to 2D-cultured-DPSC. CBD-treated microspheroids showed the most robust in situ bone regenerative potential compared with microspheroids or CBD-treated 2D-cultured-DPSC. According to mRNA sequencing, bioinformatic analysis, and confirmation study, the higher osteogenic potential of CBD-treated microspheroids was mainly attributed to WNT6 upregulation. Taken together, DPSC microspheroids have robust osteogenic potential and can effectively translate the effect of in vitro osteoinductive stimulation during in situ bone regeneration, indicating their application potential during bone defect reconstruction in clinics.

Decellularized leaf-based biomaterial supports osteogenic differentiation of dental pulp mesenchymal stem cells

Decellularized tissues are an attractive scaffolds for 3D tissue engineering. Decellularized animal tissues have certain limitations such as the availability of tissue, high costs and ethical concerns related to the use of animal sources. Plant-based tissue decellularized scaffolds could be a better option to overcome the problem. The leaves of different plants offer a unique opportunity for the development of tissue-specific scaffolds, depending on the reticulate or parallel veination. Herein, we decellularized spinach leaves and employed these for the propagation and osteogenic differentiation of dental pulp stem cells (DPSCs). DPSCs were characterized by using mesenchymal stem cell surface markers CD90, CD105 and CD73 and CD34, CD45 and HLA-DR using flow cytometry. Spinach leaves were decellularized using ethanol, NaOH and HCL. Cytotoxicity of spinach leaf scaffolds were analysed by MTT assay. Decellularized spinach leaves supported dental pulp stem cell adhesion, proliferation and osteogenic differentiation. Our data demonstrate that the decellularized spinach cellulose scaffolds can stimulate the growth, proliferation and osteogenic differentiation of DPSCs. In this study, we showed the versatile nature of decellularized plant leaves as a biological scaffold and their potential for bone regeneration in vitro.

Mesenchymal stromal cells derived from various tissues: Biological, clinical and cryopreservation aspects: Update from 2015 review

Mesenchymal stromal cells (MSCs) have become one of the most investigated and applied cells for cellular therapy and regenerative medicine. In this update of our review published in 2015, we show that studies continue to abound regarding the characterization of MSCs to distinguish them from other similar cell types, the discovery of new tissue sources of MSCs, and the confirmation of their properties and functions that render them suitable as a therapeutic. Because cryopreservation is widely recognized as the only technology that would enable the on-demand availability of MSCs, here we show that although the traditional method of cryopreserving cells by slow cooling in the presence of 10% dimethyl sulfoxide (Me2SO) continues to be used by many, several novel MSC cryopreservation approaches have emerged. As in our previous review, we conclude from these recent reports that viable and functional MSCs from diverse tissues can be recovered after cryopreservation using a variety of cryoprotectants, freezing protocols, storage temperatures, and periods of storage. We also show that for logistical reasons there are now more studies devoted to the cryopreservation of tissues from which MSCs are derived. A new topic included in this review covers the application in COVID-19 of MSCs arising from their immunomodulatory and antiviral properties. Due to the inherent heterogeneity in MSC populations from different sources there is still no standardized procedure for their isolation, identification, functional characterization, cryopreservation, and route of administration, and not likely to be a "one-size-fits-all" approach in their applications in cell-based therapy and regenerative medicine.

Evaluating the ability of cultivated odontoblasts to form dentin-like tissue in vitro using fibroblast growth factor and insulin-like growth factor

Aim

The aim of the study was to evaluate the ability of cultivated odontoblast to form dentin-like tissue using fibroblast growth factor (FGF) and insulin-like growth factor (IGF).

Materials and Methods

Dental pulp stem cells (DPSCs) were extracted from 10 human teeth. They were isolated and cultivated in vitro with the use of stem cell markers. The human DPSCs were characterized for trilineage differentiation. They were then differentiated into odontoblasts. The ability of cultivated odontoblasts to form dentin-like tissue was evaluated using FGF and IGF.

Results

IGF showed superior ability to form dentin-like tissue as compared to FGF. The addition of FGF showed no significant difference in the formation of dentin-like tissue. A combination of FGF and IGF in odontoblast showed an enhanced ability to form dentin-like tissue.

Conclusion

The use of growth factors IGF and FGF with dental stem cells showed a greater potential to form dentin-like tissue. This can profoundly alter the paradigms of conservative vital pulp therapy, which may eventually make it possible to treat dental diseases by regeneration of lost dentine.

Role of Hypoxia in Mesenchymal Stem Cells from Dental Pulp: Influence, Mechanism and Application

Mesenchymal stem cells (MSCs) from dental pulp (DP-MSCs), which include dental pulp stem cells (DPSCs) isolated from permanent teeth and stem cells from human exfoliated deciduous teeth (SHED), have emerged as highly promising cell sources for tissue regeneration, due to their high proliferative rate, multi-lineage differentiation capability and non-invasive accessibility. DP-MSCs also exert extensive paracrine effects through the release of extracellular vesicles (EVs) and multiple trophic factors. To be noted, the microenvironment, commonly referred to as the stem cell niche, plays a crucial role in shaping the functionality and therapeutic effects of DP-MSCs, within which hypoxia has garnered considerable attention. Extensive research has demonstrated that hypoxic conditions profoundly impact DP-MSCs. Specifically, hypoxia promotes DP-MSC proliferation, survival, stemness, migration, and pro-angiogenic potential while modulating their multi-lineage differentiation capacity. Furthermore, hypoxia stimulates the paracrine activities of DP-MSCs, leading to an increased production of EVs and soluble factors. Considering these findings, hypoxia preconditioning has emerged as a promising approach to enhance the therapeutic potential of DP-MSCs. In this comprehensive review, we provide a systematic overview of the influence of hypoxia on DP-MSCs, shedding light on the underlying mechanisms involved. Moreover, we also discuss the potential applications of hypoxia-preconditioned DP-MSCs or their secretome in tissue regeneration. Additionally, we delve into the methodologies employed to simulate hypoxic environments. This review aims to promote a comprehensive and systematic understanding of the hypoxia-induced effects on DP-MSCs and facilitate the refinement of regenerative therapeutic strategies based on DP-MSCs.

Elucidating epigenetic mechanisms governing odontogenic differentiation in dental pulp stem cells: an in-depth exploration

Epigenetics refers to the mechanisms such as DNA methylation and histone modification that influence gene expression without altering the DNA sequence. These epigenetic modifications can regulate gene transcription, splicing, and stability, thereby impacting cell differentiation, development, and disease occurrence. The formation of dentin is intrinsically linked to the odontogenic differentiation of dental pulp stem cells (DPSCs), which are recognized as the optimal cell source for dentin-pulp regeneration due to their varied odontogenic potential, strong proliferative and angiogenic characteristics, and ready accessibility Numerous studies have demonstrated the critical role of epigenetic regulation in DPSCs differentiation into specific cell types. This review thus provides a comprehensive review of the mechanisms by which epigenetic regulation controls the odontogenesis fate of DPSCs.

The temporospatial relationship between mouse dental pulp stem cells and tooth innervation

Background/purpose

Dental pulp stem cells (DPSCs) exhibit versatile differentiation capabilities, including neural differentiation, prompting the hypothesis that they may be implicated in the neurodevelopment of teeth. This study aimed to explore the temporospatial dynamics between DPSCs and tooth innervation, employing immunofluorescence staining and fluorescent dye injections to investigate the distribution of DPSCs, neural stem cells (NSCs), nerve growth cones, and sensory nerves in developing mouse tooth germs at various stages.

Materials and methods

Immunofluorescence staining targeting CD146, Nestin, and GAP-43, along with the injection of AM1-43 fluorescent dye, were utilized to observe the distribution of DPSCs, NSCs, nerve growth cones, and sensory nerves in mouse tooth germs at different developmental stages.

Results

Positive CD146 immunostaining was observed in microvascular endothelial cells and pericytes within and around the tooth germ. The percentage of CD146-positive cells remained consistent between 4-day-old and 8-day-old second molar tooth germs. Conversely, Nestin expression in odontoblasts and their processes decreased in 8-day-old tooth germs compared to 4-day-old ones. Positive immunostaining for GAP-43 and AM1-43 fluorescence revealed the entry of nerve growth cones and sensory nerves into the pulp in 8-day-old tooth germs, while these elements were confined to the dental follicle in 4-day-old germs. No co-localization of CD146-positive DPSCs with nerve growth cones and sensory nerves was observed.

Conclusion

DPSCs and NSCs were present in dental pulp tissue before nerves penetrated the pulp. The decline in NSCs after nerve entry suggests a potential role for DPSCs and NSCs in attracting neural growth and/or differentiation within the pulp.

Hsa_circ_0036872 has an important promotional effect in enhancing osteogenesis of dental pulp stem cells by regulating the miR-143-3p/IGF2 axis

BACKGROUND

Circular RNAs (circRNAs), an extremely stable group of RNAs, possess a covalent closed-loop configuration. Numerous studies have highlighted the involvement of circRNAs in physiological processes and the development of various diseases. The present study aimed to investigate how circRNA regulates the osteogenic differentiation of human dental pulp stem cells (hDPSCs).

METHODS

We isolated hDPSCs from dental pulp and used next-generation sequencing analysis to determine the differentially-expressed circRNAs during osteogenic differentiation. Bioinformatics and dual-luciferase reporter assays identified the downstream targets. The role of circRNAs in osteogenic differentiation was further confirmed through the use of heterotopic bone models.

RESULTS

We found that hsa_circ_0036872 expression was increased during osteogenic differentiation of hDPSCs, and downregulation of hsa_circ_0036872 inhibited their osteogenic differentiation. Dual-luciferase reporter assays showed that both miR-143-3p and IGF2 were downstream targets of hsa_circ_0036872. Overexpression of IGF2 or inhibition of miR-143-3p restored the osteogenic differentiation ability of hDPSCs after silencing hsa_circ_0036872. Overexpression of IGF2 reversed the inhibitory effect of miR-143-3p on osteogenic differentiation.

CONCLUSION

Taken together, our results show that hsa_circ_0036872 exerts an important promotional effect in enhancing the osteogenesis of dental pulp stem cells by regulating the miR-143-3p/IGF2 axis. These data suggest a novel therapeutic strategy for osteoporosis treatment and periodontal tissue regeneration.

Serine Metabolism Regulates the Replicative Senescence of Human Dental Pulp Cells through Histone Methylation

Tissue regeneration therapy based on human dental pulp cells (hDPCs) faces the distinct challenge of cellular senescence during massive expansion in vitro. To further explore the regulatory mechanism of cellular senescence in hDPCs, we conduct experiments on young cells (Passage 5, P5) and replicative senescent (Passage 12, P12) hDPCs. The results confirm that hDPCs undergo replicative senescence with passaging, during which their ability to proliferate and osteogenic differentiation decreases. Notably, during replicative senescence, phosphoglycerate dehydrogenase (PHGDH), the key enzyme of the serine synthesis pathway (SSP), is significantly downregulated, as well as S-adenosylmethionine (SAM) levels, resulting in reduced H3K36me3 modification on Sirtuin 1 (SIRT1)and Runt-related transcription factor 2 (RUNX2) promoters. Inhibition of PHGDH leads to the same phenotype as replicative senescence. Serine supplementation fails to rescue the senescence phenotype caused by replicative senescence and inhibitors, in which folate metabolism-related genes, including serine hydroxymethyl transferase 2 (SHMT2), methylenetetrahydrofolate dehydrogenase 1(MTHFD1), methylenetetrahydrofolate dehydrogenase 2(MTHFD2), are notably decreased. Our research raised a possibility that PHGDH may be involved in cellular senescence by affecting folate metabolism and histone methylation in addition to serine biosynthesis, providing potential targets to prevent senescence.

Dual-signal readout sensing of ATP content in single dental pulp stem cells during differentiation via functionalized glass nanopipettes

Adenosine triphosphate (ATP) is regarded as the "energy currency" in living cells, so real-time quantification of content variation of intracellular ATP is highly desired for understanding some important physiological processes. Due to its single-molecule readout ability, nanopipette sensing has emerged as a powerful technique for molecular sensing. In this study, based on the effect of targeting-aptamer binding on ionic current, and fluorescence resonance energy transfer (FRET), we reported a dual-signal readout nanopipette sensing system for monitoring ATP content variation at the subcellular level. In the presence of ATP, the complementary DNA-modified gold nanoparticles (cDNAs-AuNPs) were released from the inner wall of the nanopipette, which leads to sensitive response variations in ionic current rectification and fluorescence intensity. The developed nanopipette sensor was capable of detecting ATP in single cells, and the fluctuation of ATP content in the differentiation of dental pulp stem cells (DPSCs) was further quantified with this method. The study provides a more reliable nanopipette sensing platform due to the introduction of fluorescence readout signals. Significantly, the study of energy fluctuation during cell differentiation from the perspective of energy metabolism is helpful for differentiation regulation and cell therapy.

Effects of Semiconductor Laser Irradiation on Differentiation of Human Dental Pulp Stem Cells in Co-Culture with Dentin

This study aimed to determine the effect of photobiomodulation therapy induced by semiconductor laser irradiation on human dental pulp stem cell (hDPSC) proliferation and their differentiation into odontoblast-like cells (OLCs). The effects of various semiconductor laser irradiation conditions on hDPSCs were examined. Three groups were evaluated: a single laser irradiation at 6 h post-seeding, multiple laser irradiations up to four times every 4 days after the first dose, and a control with no laser irradiation. The cells were irradiated at 10, 30, and 150 mW using a semiconductor laser. The effect of laser irradiation on hDPSC differentiation into OLCs was also determined. Four groups were evaluated, including co-culture using basic medium and dentin discs, simple culture using OLC differentiation-inducing medium, co-culture using OLC differentiation-inducing medium and dentin discs, and control culture with basic medium. The expression of the nestin, ALP, DSPP, and DMP-1 genes was measured using real-time PCR. The multiple irradiation group irradiated at 30 mW exhibited significantly more cell proliferation than the control. The expression of nestin associated with differentiation into OLCs during each culture period tended to be lower, whereas DSPP and ALP expression was higher compared with that of the control. Multiple laser irradiations at a low power of 30 mW induced significant hDPSC proliferation and might induce differentiation into OLCs.

Wireless Electric Cues Mediate Autologous DPSC-Loaded Conductive Hydrogel Microspheres to Engineer the Immuno-Angiogenic Niche for Homologous Maxillofacial Bone Regeneration

Stem cell therapy serves as an effective treatment for bone regeneration. Nevertheless, stem cells from bone marrow and peripheral blood are still lacking homologous properties. Dental pulp stem cells (DPSCs) are derived from neural crest, in coincidence with maxillofacial tissues, thus attracting great interest in in situ maxillofacial regenerative medicine. However, insufficient number and heterogenous alteration of seed cells retard further exploration of DPSC-based tissue engineering. Electric stimulation has recently attracted great interest in tissue regeneration. In this study, a novel DPSC-loaded conductive hydrogel microspheres integrated with wireless electric generator is fabricated. Application of exogenous electric cues can promote stemness maintaining and heterogeneity suppression for unpredictable differentiation of encapsulated DPSCs. Further investigations observe that electric signal fine-tunes regenerative niche by improvement on DPSC-mediated paracrine pattern, evidenced by enhanced angiogenic behavior and upregulated anti-inflammatory macrophage polarization. By wireless electric stimulation on implanted conductive hydrogel microspheres, loaded DPSCs facilitates the construction of immuno-angiogenic niche at early stage of tissue repair, and further contributes to advanced autologous mandibular bone defect regeneration. This novel strategy of DPSC-based tissue engineering exhibits promising translational and therapeutic potential for autologous maxillofacial tissue regeneration.

Zirconia Hybrid Dental Implants Influence the Biological Properties of Neural Crest-Derived Mesenchymal Stromal Cells

Dental implants are regularly employed in tooth replacement, the good clinical outcome of which is strictly correlated to the choice of an appropriate implant biomaterial. Titanium-based implants are considered the gold standard for rehabilitation of edentulous spaces. However, the insurgence of allergic reactions, cellular sensitization and low integration with dental and gingival tissues lead to poor osseointegration, affecting the implant stability in the bone and favoring infections and inflammatory processes in the peri-implant space. These failures pave the way to develop and improve new biocompatible implant materials. CERID dental implants are made of a titanium core embedded in a zirconium dioxide ceramic layer, ensuring absence of corrosion, a higher biological compatibility and a better bone deposition compared to titanium ones. We investigated hDPSCs' biological behavior, i.e., cell adhesion, proliferation, morphology and osteogenic potential, when seeded on both CERID and titanium implants, before and after cleansing with two different procedures. SEM and AFM analysis of the surfaces showed that while CERID disks were not significantly affected by the cleansing system, titanium ones exhibited well-visible modifications after brush treatment, altering cell morphology. The proliferation rate of DPSCs was increased for titanium, while it remained unaltered for CERID. Both materials hold an intrinsic potential to promote osteogenic commitment of neuro-ectomesenchymal stromal cells. Interestingly, the CERID surface mitigated the immune response by inducing an upregulation of anti-inflammatory cytokine IL-10 on activated PBMCs when a pro-inflammatory microenvironment was established. Our in vitro results pave the way to further investigations aiming to corroborate the potential of CERID implants as suitable biomaterials for dental implant applications.

Flavonoid extract from propolis alleviates periodontitis by boosting periodontium regeneration and inflammation resolution via regulating TLR4/MyD88/NF-κB and RANK/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Chinese medicine, propolis has been used for treating oral diseases for centuries, widely. Flavonoid extract is the main active ingredient in propolis, which has attracted extensive attention in recent years.

AIM OF THE STUDY

The objective and novelty of the current study aims to identify the mechanism of total flavonoid extract of propolis (TFP) for the treatment of periodontitis, and evaluate the therapeutic effect of TFP-loaded liquid crystal hydrogel (TFP-LLC) in rats with periodontitis.

METHODS

In this study, we used lipopolysaccharide-stimulated periodontal ligament stem cells (PDLSCs) to construct in vitro inflammation model, and investigated the anti-inflammatory effect of TFP by expression levels of inflammatory factors. Osteogenic differentiation was assessed using alkaline phosphatase activity and alizarin red staining. Meanwhile, the expression of toll like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), nuclear factor-kappa B (NF-κB), receptor activator of NF-κB (RANK) etc, were quantitated to investigate the therapeutic mechanism of TFP. Finally, we constructed TFP-LLC using a self-emulsification method and administered it to rats with periodontitis via periodontal pocket injection to evaluate the therapeutic effects. The therapeutic index, microcomputed tomography (Micro-CT), H&E staining, TRAP staining, and Masson staining were used for this evaluation.

RESULTS

TFP reduced the expression of TLR4, MyD88, NF-κB and inflammatory factor in lipopolysaccharide-stimulated PDLSCs. Meanwhile, TFP simultaneously regulating alkaline phosphatase, RANK, runt-associated transcription factor-2 and matrix metalloproteinase production to accelerate osteogenic differentiation and collagen secretion. In addition, TFP-LLC can stably anchor to the periodontal lesion site and sustainably release TFP. After four weeks of treatment with TFP-LLC, we observed a decrease in the levels of NF-κB and interleukin-1β (IL-1β) in the periodontal tissues of rats, as well as a significant reduction in inflammation in HE staining. Similarly, Micro CT results showed that TFP-LLC could significantly inhibit alveolar bone resorption, increase bone mineral density (BMD) and reduce trabecular bone space (Tb.Sp) in rats with periodontitis.

CONCLUSION

Collectively, we have firstly verified the therapeutic effects and mechanisms of TFP in PDLSCs for periodontitis treatment. Our results indicate that TFP perform anti-inflammatory and tissue repair activities through TLR4/MyD88/NF-κB and RANK/NF-κB pathways in PDLSCs. Meanwhile, for the first time, we employed LLC delivery system to load TFP for periodontitis treatment. The results showed that TFP-LLC could be effectively retained in the periodontal pocket and exerted a crucial role in inflammation resolution and periodontal tissue regeneration.

MicroRNA-93-5p regulates odontogenic differentiation and dentin formation via KDM6B

BACKGROUND

Epigenetic factors influence the odontogenic differentiation of dental pulp stem cells and play indispensable roles during tooth development. Some microRNAs can epigenetically regulate other epigenetic factors like DNA methyltransferases and histone modification enzymes, functioning as epigenetic-microRNAs. In our previous study, microarray analysis suggested microRNA-93-5p (miR-93-5p) was differentially expressed during the bell stage in human tooth germ. Prediction tools indicated that miR-93-5p may target lysine-specific demethylase 6B (KDM6B). Therefore, we explored the role of miR-93-5p as an epi-miRNA in tooth development and further investigated the underlying mechanisms of miR-93-5p in regulating odontogenic differentiation and dentin formation.

METHODS

The expression pattern of miR-93-5p and KDM6B of dental pulp stem cells (DPSCs) was examined during tooth development and odontogenic differentiation. Dual luciferase reporter and ChIP-qPCR assay were used to validate the target and downstream regulatory genes of miR-93-5p in human DPSCs (hDPSCs). Histological analyses and qPCR assays were conducted for investigating the effects of miR-93-5p mimic and inhibitor on odontogenic differentiation of hDPSCs. A pulpotomy rat model was further established, microCT and histological analyses were performed to explore the effects of KDM6B-overexpression and miR-93-5p inhibition on the formation of tertiary dentin.

RESULTS

The expression level of miR-93-5p decreased as odontoblast differentiated, in parallel with elevated expression of histone demethylase KDM6B. In hDPSCs, miR-93-5p overexpression inhibited the odontogenic differentiation and vice versa. MiR-93-5p targeted 3' untranslated region (UTR) of KDM6B, thereby inhibiting its protein translation. Furthermore, KDM6B bound the promoter region of BMP2 to demethylate H3K27me3 marks and thus upregulated BMP2 transcription. In the rat pulpotomy model, KDM6B-overexpression or miR-93-5p inhibition suppressed H3K27me3 level in DPSCs and consequently promoted the formation of tertiary dentin.

CONCLUSIONS

MiR-93-5p targets epigenetic regulator KDM6B and regulates H3K27me3 marks on BMP2 promoters, thus modulating the odontogenic differentiation of DPSCs and dentin formation.

Apoptosis Regulation in Dental Pulp Cells and PD-1/PD-L1 Expression Dynamics Under Ozone Exposure - A Pilot Approach

This study aimed to determine the effect of ozone on the expression of Bax and Bcl-2 genes in dental pulp cells. Additionally, the programmed cell death protein 1, programmed death-ligand 1, and CD200 antigens were determined in lymphocytes to assess their surface expression. Dental pulp cells were cultured from extracted healthy third molars and characterized as dental pulp stromal cells. Gene expression of Bcl-2 and Bax was analyzed at 0 s, 6 s, and 12 s of ozone exposure using real-time PCR. Lymphocytes from dental pulp were subjected to ozone exposure for 12 s and PD-1, PD-L1, and CD200/CD200R expression was analyzed by flow cytometry. Upon exposure to ozone for 6 s, the Bcl-2 expression decreased significantly to -0.09, and at 12 s, it increased significantly to 0.3. Bax gene expression level increased significantly to 0.188 after 6 s exposure, and at 12 s, to 0.16. Lymphocytes exposed to ozone for 12 s showed minimal changes in PD-1, PD-L1, and CD200/CD200R expression levels, indicating that oxidative stress does not impact the signaling pathways regulating these molecules. The significant upregulation of Bcl-2 at 12 s highlights the cells' effort to protect themselves from prolonged oxidative stress, possibly tipping the balance toward cell survival and tissue repair. However, the absence of changes in PD-1 and PD-L1 expression on lymphocytes under oxidative stress suggests that these molecules are not sensitive to oxidative stress in this context.

Isolation and Characterization of Human Dental Pulp Stem Cells Derived from Dental Pulp of Permanent Teeth

Dental pulp stem cells (DPSCs) are a promising alternative to the source of mesenchymal stem cells (MSCs), as they are readily available in minimally invasive procedures compared to more invasive methods associated with harvesting other MSCs sources. Despite the encouraging pre-clinical outcomes in animal disease models, culture-expanding procedures are needed to obtain a sufficient number of MSCs required for delivery to the damaged site. However, this contributes to increasing regulatory difficulties in translating stem cells and tissue engineering therapy to clinical use. Moreover, discussions continue as to which isolation method is to be preferred when obtaining DPSCs from extracted molars. This protocol describes a simple explant isolation technique of human dental pulp stem cells from the dental pulp of permanent teeth based upon the plastic adherence of MSCs and subsequent outgrowth of cells out of tissue fragments with high efficacy.

Analogies and Differences Between Dental Stem Cells: Focus on Secretome in Combination with Scaffolds in Neurological Disorders

Mesenchymal stem cells (MSCs) are well known for their beneficial effects, differentiation capacity and regenerative potential. Dental-derived MSCs (DSCs) are more easily accessible and have a non-invasive isolation method rather than MSCs isolated from other sources (umbilical cord, bone marrow, and adipose tissue). In addition, DSCs appear to have a relevant neuro-regenerative potential due to their neural crest origin. However, it is now known that the beneficial effects of MSCs depend, at least in part, on their secretome, referring to all the bioactive molecules (neurotrophic factors) released in the conditioned medium (CM) or in the extracellular vesicles (EVs) in particular exosomes (Exos). In this review, we described the similarities and differences between various DSCs. Our focus was on the secretome of DSCs and their applications in cell therapy for neurological disorders. For neuro-regenerative purposes, the secretome of different DSCs has been tested. Among these, the secretome of dental pulp stem cells and stem cells from human exfoliated deciduous teeth have been the most widely studied. Both CM and Exos obtained from DSCs have been shown to promote neurite outgrowth and neuroprotective effects as well as their combination with scaffold materials (to improve their functional integration in the tissue). For these reasons, the secretome obtained from DSCs in combination with scaffold materials may represent a promising tissue engineering approach for neuroprotective and neuro-regenerative treatments.

The Biological Significance of AFF4: Promoting Transcription Elongation, Osteogenic Differentiation and Tumor Progression

As a member of the AF4/FMR2 (AFF) family, AFF4 is a scaffold protein in the superelongation complex (SEC). In this mini-view, we discuss the role of AFF4 as a transcription elongation factor that mediates HIV activation and replication and stem cell osteogenic differentiation. AFF4 also promotes the progression of head and neck squamous cell carcinoma, leukemia, breast cancer, bladder cancer and other malignant tumors. The biological function of AFF4 is largely achieved through SEC assembly, regulates SRY-box transcription factor 2 (SOX2), MYC, estrogen receptor alpha (ESR1), inhibitor of differentiation 1 (ID1), c-Jun and noncanonical nuclear factor-κB (NF-κB) transcription and combines with fusion in sarcoma (FUS), unique regulatory cyclins (CycT1), or mixed lineage leukemia (MLL). We explore the prospects of using AFF4 as a therapeutic in Acquired immunodeficiency syndrome (AIDS) and malignant tumors and its potential as a stemness regulator.

A Review of Extraction and Purification, Biological Properties, Structure-Activity Relationships and Future Prospects of Schisandrin C: A Major Active Constituent of Schisandra Chinensis

Since ancient times, China has used natural medicine as the primary way to combat diseases and has a rich arsenal of natural medicines. With the progress of the times, the extraction of bioactive molecules from natural drugs has become the new development direction for natural medicines. Among the numerous natural drugs, Schisandrin C (Sch C), derived from Schisandra Chinensis (Turcz.) Baill. It has excellent potential for development and has been shown to possess various pharmacological properties, including hepatoprotective, antitumor and anti-inflammatory activities. Based on the biological properties of hepatoprotection, scholars have explored Sch C and its synthetic products in depth; some studies have shown that pentosidine has the effect of improving the symptoms of liver fibrosis and reducing the concentration of alanine transaminase (ALT) and aspartate aminotransferase (AST) in the serum of rats, which is an essential inspiration for the development of anti-liver fibrosis drugs. But more in vivo and ex vivo studies still need to be included. This paper focuses on Sch C's extraction and synthesis, biological activities and drug development progress. The future application prospects of Sch C are discussed to perfect its development work further.

Approaches to vital pulp therapies

Tooth decay, which leads to pulpal inflammation due to the pulp's response to bacterial components and byproducts is the most common infectious disease. The main goals of clinical management are to eliminate sources of infection, to facilitate healing by regulating inflammation indental tissue, and to replace lost tissues. A variety of novel approaches from tissue engineering based on stem cells, bioactive molecules, and extracellular matrix-like scaffold structures to therapeutic applications, or a combination of all these are present in the literature. Shortcomings of existing conventional materials for pulp capping and the novel approches aiming to preserve pulp vitality highligted the need for developing new targeted dental materials. This review looks at the novel approches for vital pulp treatments after briefly addresing the conventional vital pulp treatment as well as the regenerative and self defense capabilities of the pulp. A narrative review focusing on the current and future approaches for pulp preservation was performed after surveying the relevant papers on vital pulp therapies including pulp capping, pulpotomy, and potential approaches for facilitating dentin-pulp complex regeneration in PubMed, Medline, and Scopus databases.

Lipid rafts mediate multilineage differentiation of human dental pulp-derived stem cells (DPSCs)

Cell outer membranes contain glycosphingolipids and protein receptors, which are integrated into glycoprotein domains, known as lipid rafts, which are involved in a variety of cellular processes, including receptor-mediated signal transduction and cellular differentiation process. In this study, we analyzed the lipidic composition of human Dental Pulp-Derived Stem Cells (DPSCs), and the role of lipid rafts during the multilineage differentiation process. The relative quantification of lipid metabolites in the organic fraction of DPSCs, performed by Nuclear Magnetic Resonance (NMR) spectroscopy, showed that mono-unsaturated fatty acids (MUFAs) were the most representative species in the total pool of acyl chains, compared to polyunsatured fatty acids (PUFAs). In addition, the stimulation of DPSCs with different culture media induces a multilineage differentiation process, determining changes in the gangliosides pattern. To understand the functional role of lipid rafts during multilineage differentiation, DPSCs were pretreated with a typical lipid raft affecting agent (MβCD). Subsequently, DPSCs were inducted to differentiate into osteoblast, chondroblast and adipoblast cells with specific media. We observed that raft-affecting agent MβCD prevented AKT activation and the expression of lineage-specific mRNA such as OSX, PPARγ2, and SOX9 during multilineage differentiation. Moreover, this compound significantly prevented the tri-lineage differentiation induced by specific stimuli, indicating that lipid raft integrity is essential for DPSCs differentiation. These results suggest that lipid rafts alteration may affect the signaling pathway activated, preventing multilineage differentiation.

Potential of dental pulp stem cells and their products in promoting peripheral nerve regeneration and their future applications

Peripheral nerve injury (PNI) seriously affects people's quality of life. Stem cell therapy is considered a promising new option for the clinical treatment of PNI. Dental stem cells, particularly dental pulp stem cells (DPSCs), are adult pluripotent stem cells derived from the neuroectoderm. DPSCs have significant potential in the field of neural tissue engineering due to their numerous advantages, such as easy isolation, multidifferentiation potential, low immunogenicity, and low transplant rejection rate. DPSCs are extensively used in tissue engineering and regenerative medicine, including for the treatment of sciatic nerve injury, facial nerve injury, spinal cord injury, and other neurodegenerative diseases. This article reviews research related to DPSCs and their advantages in treating PNI, aiming to summarize the therapeutic potential of DPSCs for PNI and the underlying mechanisms and providing valuable guidance and a foundation for future research.

Effects of different signaling pathways on odontogenic differentiation of dental pulp stem cells: a review

Dental pulp stem cells (DPSCs) are a type of mesenchymal stem cells that can differentiate into odontoblast-like cells and protect the pulp. The differentiation of DPSCs can be influenced by biomaterials or growth factors that activate different signaling pathways in vitro or in vivo. In this review, we summarized six major pathways involved in the odontogenic differentiation of DPSCs, Wnt signaling pathways, Smad signaling pathways, MAPK signaling pathways, NF-kB signaling pathways, PI3K/AKT/mTOR signaling pathways, and Notch signaling pathways. Various factors can influence the odontogenic differentiation of DPSCs through one or more signaling pathways. By understanding the interactions between these signaling pathways, we can expand our knowledge of the mechanisms underlying the regeneration of the pulp-dentin complex.

GATA4 inhibits odontoblastic differentiation of dental pulp stem cells through targeting IGFBP3

OBJECTIVE

The odontogenic differentiation of human dental pulp stem cells (HDPSCs) is associated with reparative dentinogenesis. Transcription factor GATA binding protein 4 (GATA4) is proved to be essential for osteoblast differentiation and bone remodeling. This study clarified the function of GATA4 in HDPSCs odontoblast differentiation.

METHODS

The change in GATA4 expression during reparative dentin formation was detected by immunohistochemistry staining. The expression of GATA4 during HDPSCs odontoblastic differentiation was detected by western blot and quantitative polymerase chain reaction. The effect of GATA4 on odontoblast differentiation was investigated following overexpression lentivirus transfection. RNA sequencing, dual luciferase assay and chromatin immunoprecipitation (CHIP) were conducted to verify downstream targets of GATA4. GATA4 overexpression lentivirus and small interference RNA targeting IGFBP3 were co-transfected to investigate the regulatory mechanism of GATA4.

RESULTS

Upregulated GATA4 was observed during reparative dentin formation in vivo and the odontoblastic differentiation of HDPSCs in vitro. GATA4 overexpression suppressed the odontoblastic potential of HDPSCs, demonstrated by decreased alkaline phosphatase activity (p < 0.0001), mineralized nodules formation (p < 0.01), and odonto/osteogenic differentiation markers levels (p < 0.05). RNA sequencing revealed IGFBP3 was a potential target of GATA4. CHIP and dual luciferase assays identified GATA4 could activate IGFBP3 transcription. Additionally, IGFBP3 knockdown recovered the odontoblastic differentiation defect caused by GATA4 overexpression (p < 0.05).

CONCLUSIONS

GATA4 inhibited odontoblastic differentiation of HDPSCs via activating the transcriptional activity of IGFBP3, identifying its promising role in regulating HDPSCs odontoblast differentiation and reparative dentinogenesis.

The odontoblastic differentiation of dental mesenchymal stem cells: molecular regulation mechanism and related genetic syndromes

Dental mesenchymal stem cells (DMSCs) are multipotent progenitor cells that can differentiate into multiple lineages including odontoblasts, osteoblasts, chondrocytes, neural cells, myocytes, cardiomyocytes, adipocytes, endothelial cells, melanocytes, and hepatocytes. Odontoblastic differentiation of DMSCs is pivotal in dentinogenesis, a delicate and dynamic process regulated at the molecular level by signaling pathways, transcription factors, and posttranscriptional and epigenetic regulation. Mutations or dysregulation of related genes may contribute to genetic diseases with dentin defects caused by impaired odontoblastic differentiation, including tricho-dento-osseous (TDO) syndrome, X-linked hypophosphatemic rickets (XLH), Raine syndrome (RS), hypophosphatasia (HPP), Schimke immuno-osseous dysplasia (SIOD), and Elsahy-Waters syndrome (EWS). Herein, recent progress in the molecular regulation of the odontoblastic differentiation of DMSCs is summarized. In addition, genetic syndromes associated with disorders of odontoblastic differentiation of DMSCs are discussed. An improved understanding of the molecular regulation and related genetic syndromes may help clinicians better understand the etiology and pathogenesis of dentin lesions in systematic diseases and identify novel treatment targets.

Advances in combined application of dental stem cells and small-molecule drugs in regenerative medicine

Teeth are a kind of masticatory organs of special histological origin, unique to vertebrates, playing an important role in chewing, esthetics, and auxiliary pronunciation. In the past decades, with the development of tissue engineering and regenerative medicine, the studies of mesenchymal stem cells (MSCs) gradually attracted the interest of researchers. Accordingly, several types of MSCs have been successively isolated in teeth or teeth-related tissues, including dental pulp stem cells, periodontal ligament stem cells, stem cells from human exfoliated deciduous teeth, dental follicle stem cells, stem cells from apical papilla and gingival mesenchymal stem cells. These dental stem cells (DSCs) are easily accessible, possess excellent stem cell characteristics, such as high proliferation rates and profound immunomodulatory properties. Small-molecule drugs are widely used and show great advantages in clinical practice. As research progressed, small-molecule drugs are found to have various complex effects on the characteristics of DSCs, especially the enhancement of biological characteristics of DSCs, which has gradually become a hot issue in the field of DSCs research. This review summarizes the background, current status, existing problems, future research directions, and prospects of the combination of DSCs with three common small-molecule drugs: aspirin, metformin, and berberine.

Improved Method for Dental Pulp Stem Cell Preservation and Its Underlying Cell Biological Mechanism

Dental pulp stem cells (DPSCs) are considered a valuable cell source for regenerative medicine because of their high proliferative potential, multipotency, and availability. We established a new cryopreservation method (NCM) for collecting DPSCs, in which the tissue itself is cryopreserved and DPSCs are collected after thawing. We improved the NCM and developed a new method for collecting and preserving DPSCs more efficiently. Dental pulp tissue was collected from an extracted tooth, divided into two pieces, sandwiched from above and below using cell culture inserts, and cultured. As a result, the cells in the pulp tissue migrated vertically over time and localized near the upper and lower membranes over 2-3 days. With regard to the underlying molecular mechanism, SDF1 was predominantly involved in cell migration. This improved method is valuable and enables the more efficient collection and reliable preservation of DPSCs. It has the potential to procure a large number of DPSCs stably.

TGF-β promotes the proliferation and osteogenic differentiation of dental pulp stem cells a systematic review and meta-analysis

BACKGROUND

Dental pulp stem cells (DPSCs) are adult stem cells with multi-directional differentiation potential derived from ectoderm. Vitro experiments have shown that adding cytokines can help DPSCs to be transformed from multipotent stem cells to osteoblasts. TGF-β has been proved to have an effect on the proliferation and mineralization of bone tissue, but its effect on the osteogenesis and proliferation of dental pulp stem cells is still uncertain. We aim to determine the effect of TGF-β on the osteogenesis and proliferation of dental pulp stem cells.

METHODS

We have identified studies from the Cochrane Central Register of Controlled Trials, PubMed, Embase, and China national knowledge infrastructure (CNKI) for studies interested in TGF-β and proliferation and differentiation of dental pulp stem cells in the following indicators: A490 (an index for evaluating cell proliferation), bone sialoprotein (BSP), Col plasmid-1 (Col-1), osteocalcin (OCN), runt-related transcription factor 2 (Runx-2); and the number of mineralized nodules. Any language restrictions were rejected. Furthermore, we drew a forest plot for each outcome. We conducted a sensitivity analysis, data analysis, heterogeneity, and publication bias test. We evaluate the quality of each study under the guidance of Cochrane's tool for quality assessment.

RESULTS

The pooled data showed that TGF-β could promote the proliferation and ossification of dental pulp stem cells. All the included results support this conclusion except for the number of mineralized nodules: TGF-β increases the A490 index (SMD 3.11, 95% CI [0.54-5.69]), promotes the production of BSP (SMD 3.11, 95% CI [0.81-6.77]), promotes the expression of Col-1 (SMD 4.71, 95% CI [1.25-8.16]) and Runx-2 (SMD 3.37, 95% CI [- 0.63 to 7.36]), increases the content of OCN (SMD 4.32, 95% CI [1.20-7.44]) in dental pulp, and has no significant effect on the number of mineralized nodules (SMD 3.87, 95% CI [- 1.76 to 9.51]) in dental pulp stem cells.

CONCLUSIONS

TGF-β promotes the proliferation and osteogenesis of dental pulp stem cells.

Engineering the Future of Dental Health: Exploring Molecular Advancements in Dental Pulp Regeneration

Protected by the surrounding mineralized barriers of enamel, dentin, and cementum, dental pulp is a functionally versatile tissue that fulfills multiple roles [...].

Effects of Bacterial Metabolites on the Wnt4 Protein in Dental-Pulp-Stem-Cells-Based Endodontic Pulpitis Treatment

Porphyromonas gingivalis is associated with endodontic pulpitis, causing damage to the dental pulp, leading to severe pain and a decline in quality of life. Regenerative pulp treatments using dental pulp stem cells (DPSCs) can be hindered by interactions between DPSCs and the infecting bacteria. The protein WNT family member 4 (Wnt4) plays a critical role in the differentiation of DPSCs and the regeneration of odontogenic tissue. However, the specific influence of P. gingivalis on Wnt4 remains unclear. In this study, we employed a computational approach to investigate the underlying mechanisms through which P. gingivalis-produced metabolites inhibit the Wnt4 protein, thereby diminishing the regenerative potential and therapeutic efficacy of odontogenic tissue. Among the metabolites examined, C₂₉H₄₆N₇O₁₈P₃S^-4 exhibited the strongest inhibitory effect on the Wnt4 protein, as evidenced by the lowest binding energy score of -6782 kcal/mol. Molecular dynamic simulation trajectories revealed that the binding of C₂₉H₄₆N₇O₁₈P₃S^-4 significantly altered the structural dynamics and stability of the Wnt4 protein. These alterations in protein trajectories may have implications for the molecular function of Wnt4 and its associated pathways. Overall, our findings shed light on the inhibitory impact of P. gingivalis-produced metabolites on the Wnt4 protein. Further in vitro, in vivo, and clinical studies are necessary to validate and expand upon our findings.

Dental Materials Applied to 3D and 4D Printing Technologies: A Review

As computer-aided design and computer-aided manufacturing (CAD/CAM) technologies have matured, three-dimensional (3D) printing materials suitable for dentistry have attracted considerable research interest, owing to their high efficiency and low cost for clinical treatment. Three-dimensional printing technology, also known as additive manufacturing, has developed rapidly over the last forty years, with gradual application in various fields from industry to dental sciences. Four-dimensional (4D) printing, defined as the fabrication of complex spontaneous structures that change over time in response to external stimuli in expected ways, includes the increasingly popular bioprinting. Existing 3D printing materials have varied characteristics and scopes of application; therefore, categorization is required. This review aims to classify, summarize, and discuss dental materials for 3D printing and 4D printing from a clinical perspective. Based on these, this review describes four major materials, i.e., polymers, metals, ceramics, and biomaterials. The manufacturing process of 3D printing and 4D printing materials, their characteristics, applicable printing technologies, and clinical application scope are described in detail. Furthermore, the development of composite materials for 3D printing is the main focus of future research, as combining multiple materials can improve the materials' properties. Updates in material sciences play important roles in dentistry; hence, the emergence of newer materials are expected to promote further innovations in dentistry.

Epithelium-derived SCUBE3 promotes polarized odontoblastic differentiation of dental mesenchymal stem cells and pulp regeneration

BACKGROUND

Signal peptide-CUB-EGF domain-containing protein 3 (SCUBE3), a secreted multifunctional glycoprotein whose transcript expression is restricted to the tooth germ epithelium during the development of embryonic mouse teeth, has been demonstrated to play a crucial role in the regulation of tooth development. Based on this, we hypothesized that epithelium-derived SCUBE3 contributes to bio-function in dental mesenchymal cells (Mes) via epithelium-mesenchyme interactions.

METHODS

Immunohistochemical staining and a co-culture system were used to reveal the temporospatial expression of the SCUBE3 protein during mouse tooth germ development. In addition, human dental pulp stem cells (hDPSCs) were used as a Mes model to study the proliferation, migration, odontoblastic differentiation capacity, and mechanism of rhSCUBE3. Novel pulp-dentin-like organoid models were constructed to further confirm the odontoblast induction function of SCUBE3. Finally, semi-orthotopic animal experiments were performed to explore the clinical application of rhSCUBE3. Data were analysed using one-way analysis of variance and t-tests.

RESULTS

The epithelium-derived SCUBE3 translocated to the mesenchyme via a paracrine pathway during mouse embryonic development, and the differentiating odontoblasts in postnatal tooth germ subsequently secreted the SCUBE3 protein via an autocrine mechanism. In hDPSCs, exogenous SCUBE3 promoted cell proliferation and migration via TGF-β signalling and accelerated odontoblastic differentiation via BMP2 signalling. In the semi-orthotopic animal experiments, we found that SCUBE3 pre-treatment-induced polarized odontoblast-like cells attached to the dental walls and had better angiogenesis performance.

CONCLUSION

SCUBE3 protein expression is transferred from the epithelium to mesenchyme during embryonic development. The function of epithelium-derived SCUBE3 in Mes, including proliferation, migration, and polarized odontoblastic differentiation, and their mechanisms are elaborated for the first time. These findings shed light on exogenous SCUBE3 application in clinic dental pulp regeneration.

Immunomodulatory Mechanism and Potential Application of Dental Pulp-Derived Stem Cells in Immune-Mediated Diseases

Dental pulp stem cells (DPSCs) are mesenchymal stem cells (MSCs) derived from dental pulp tissue, which have high self-renewal ability and multi-lineage differentiation potential. With the discovery of the immunoregulatory ability of stem cells, DPSCs have attracted much attention because they have similar or even better immunomodulatory effects than MSCs from other sources. DPSCs and their exosomes can exert an immunomodulatory ability by acting on target immune cells to regulate cytokines. DPSCs can also migrate to the lesion site to differentiate into target cells to repair the injured tissue, and play an important role in tissue regeneration. The aim of this review is to summarize the molecular mechanism and target cells of the immunomodulatory effects of DPSCs, and the latest advances in preclinical research in the treatment of various immune-mediated diseases, providing new reflections for their clinical application. DPSCs may be a promising source of stem cells for the treatment of immune-mediated diseases.

Promotive Effect of FBXO32 on the Odontoblastic Differentiation of Human Dental Pulp Stem Cells

Odontoblastic differentiation of human dental pulp stem cells (hDPSCs) is crucial for the intricate formation and repair processes in dental pulp. Until now, the literature is not able to demonstrate the role of ubiquitination in the odontoblastic differentiation of hDPSCs. This study investigated the role of F-box-only protein 32 (FBXO32), an E3 ligase, in the odontoblastic differentiation of hDPSCs. The mRNA expression profile was obtained from ribonucleic acid sequencing (RNA-Seq) data and analyzed. Immunofluorescence and immunohistochemical staining identify the FBXO32 expression in human dental pulp and hDPSCs. Small-hairpin RNA lentivirus was used for FBXO32 knockdown and overexpression. Odontoblastic differentiation of hDPSCs was determined via alkaline phosphatase activity, Alizarin Red S staining, and mRNA and protein expression levels were detected using real-time quantitative polymerase chain reaction and Western blotting. Furthermore, subcutaneous transplantation in nude mice was performed to evaluate the role of FBXO32 in mineralization in vivo using histological analysis. FBXO32 expression was upregulated in the odontoblast differentiated hDPSCs as evidenced by RNA-Seq data analysis. FBXO32 was detected in hDPSCs and the odontoblast layer of the dental pulp. Increased FBXO32 expression in hDPSCs during odontoblastic differentiation was confirmed. Through lentivirus infection method, FBXO32 downregulation in hDPSCs attenuated odontoblastic differentiation in vitro and in vivo, whereas FBXO32 upregulation promoted the hDPSCs odontoblastic differentiation, without affecting proliferation and migration. This study demonstrated, for the first time, the promotive role of FBXO32 in regulating the odontoblastic differentiation of hDPSCs, thereby providing novel insights into the regulatory mechanisms during odontoblastic differentiation in hDPSCs.

Neurological Disease Modeling Using Pluripotent and Multipotent Stem Cells: A Key Step towards Understanding and Treating Mucopolysaccharidoses

Despite extensive research, the links between the accumulation of glycosaminoglycans (GAGs) and the clinical features seen in patients suffering from various forms of mucopolysaccharidoses (MPSs) have yet to be further elucidated. This is particularly true for the neuropathology of these disorders; the neurological symptoms are currently incurable, even in the cases where a disease-specific therapeutic approach does exist. One of the best ways to get insights on the molecular mechanisms driving that pathogenesis is the analysis of patient-derived cells. Yet, not every patient-derived cell recapitulates relevant disease features. For the neuronopathic forms of MPSs, for example, this is particularly evident because of the obvious inability to access live neurons. This scenario changed significantly with the advent of induced pluripotent stem cell (iPSC) technologies. From then on, a series of differentiation protocols to generate neurons from iPSC was developed and extensively used for disease modeling. Currently, human iPSC and iPSC-derived cell models have been generated for several MPSs and numerous lessons were learnt from their analysis. Here we review most of those studies, not only listing the currently available MPS iPSC lines and their derived models, but also summarizing how they were generated and the major information different groups have gathered from their analyses. Finally, and taking into account that iPSC generation is a laborious/expensive protocol that holds significant limitations, we also hypothesize on a tempting alternative to establish MPS patient-derived neuronal cells in a much more expedite way, by taking advantage of the existence of a population of multipotent stem cells in human dental pulp to establish mixed neuronal and glial cultures.

TLR3 recognition of viral double-stranded RNA in human dental pulp cells is important for the innate immunity

Dental caries or trauma can expose human dental pulp cells (DPCs) to various oral microorganisms, which play an important role in the development of an innate immune response. In the present study, we examined the expression of Toll-like receptors (TLRs) for sensing microbe-associated molecular patterns in human DPCs. Interestingly, real-time PCR analysis demonstrated that TLR3 is the most highly expressed among 10 different TLRs in human DPCs. Poly(I:C), a representative TLR3 ligand mimicking viral double-stranded RNA, potently induced IL-8 expression in a time- and dose-dependent manner. Concordantly, poly(I:C) treatment substantially increased the expression of pro-inflammatory cytokines and chemokines such as IL-6, CCL2, and CXCL10. Human DPCs transfected with TLR3 siRNA exhibited decreased IL-8 production compared with non-targeting siRNA-transfected cells, suggesting that the expression of poly(I:C)-induced inflammatory cytokines is dependent on TLR3. IL-8 secretion induced by poly(I:C) was down-regulated by MAP kinase inhibitors, indicating that the MAP kinase pathway contributes to IL-8 production. Furthermore, C/EBPβ and NF-κB were essential transcriptional factors for poly(I:C)-induced IL-8 expression, as demonstrated by the transient transfection and reporter gene assay. Since lipoproteins are known as major immunostimulatory components of bacteria, human DPCs were treated with poly(I:C) together with Pam2CSK4, a synthetic lipopeptide mimicking bacterial lipoproteins. Pam2CSK4 and poly(I:C) co-treatment synergistically increased IL-8 production in comparison to Pam2CSK4 or poly(I:C) alone, implying that co-infection of viruses and bacteria can synergistically induce inflammatory responses in the dental pulp. Taken together, these results suggest that human DPCs potentially sense and respond to viral double-stranded RNAs, leading to effective induction of innate immune responses.

MicroRNAs-mediated regulation of the differentiation of dental pulp-derived mesenchymal stem cells: a systematic review and bioinformatic analysis

BACKGROUND

Human dental pulp-derived mesenchymal stem cells (hDP-MSCs), which include human dental pulp stem cells (hDPSCs) and stem cells from human exfoliated deciduous teeth (SHEDs), are promising cell sources for regenerative therapies. Nevertheless, a lack of knowledge relating to the mechanisms regulating their differentiation has limited their clinical application. microRNAs (miRNAs) are important regulatory molecules in cellular processes including cell differentiation. This systematic review aims to provide a panel of miRNAs that regulate the differentiation of hDP-MSCs including hDPSCs and SHEDs. Additionally, bioinformatic analyses were conducted to discover target genes, signaling pathways and gene ontologies associated with the identified miRNAs.

METHODS

A literature search was performed in MEDLINE (via PubMed), Web of Science, Scopus, Embase and Cochrane Library. Experimental studies assessing the promotive/suppressive effect of miRNAs on the differentiation of hDP-MSCs and studies evaluating changes to the expression of miRNAs during the differentiation of hDP-MSCs were included. miRNAs involved in odontogenic/osteogenic differentiation were then included in a bioinformatic analysis. A miRNA-mRNA network was constructed, and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed. A protein-protein interaction (PPI) network was also constructed.

RESULTS

Of 766 initially identified records through database searching, 42 and 36 studies were included in qualitative synthesis and bioinformatic analyses, respectively. Thirteen miRNAs promoted and 17 suppressed odontogenic/osteogenic differentiation of hDP-MSCs. hsa-miR-140-5p, hsa-miR-218 and hsa-miR-143 were more frequently reported suppressing the odontogenic/osteogenic differentiation of hDP-MSCs. hsa-miR-221 and hsa-miR-124 promoted and hsa-miR-140-5p inhibited neuronal differentiation, hsa-miR-26a-5p promoted and hsa-miR-424 suppressed angiogenic differentiation, and hsa-miR-135 and hsa-miR-143 inhibited differentiation within myogenic lineages. A miRNA-mRNA network including 1890 nodes and 2171 edges was constructed. KEGG pathway analysis revealed MAPK, PI3K-Akt and FoxO as key signaling pathways involved in the odontogenic/osteogenic differentiation of hDP-MSCs.

CONCLUSIONS

The findings of this systematic review support the potential application of the specific miRNAs to regulate the directed differentiation of hDP-MSCs in the field of regenerative therapies.

The role of EMILIN-1 in the osteo/odontogenic differentiation of dental pulp stem cells

BACKGROUND

Human dental pulp stem cells (hDPSCs) may be the best choice for self-repair and regeneration of teeth and maxillofacial bone tissue due to their homogeneous tissue origin, high proliferation and differentiation rates, and no obvious ethical restrictions. Recently, several studies have shown that extracellular matrix (ECM) proteins can effectively regulate the proliferation and differentiation fate of mesenchymal stem cells (MSCs). However, the role of elastin microfibril interface-located protein-1 (EMILIN-1), a new ECM glycoprotein, in osteo/odontogenic differentiation of hDPSCs has not been reported. The aim of this study was to explore the effect of EMILIN-1 during osteo/odontogenic differentiation of hDPSCs.

METHODS

hDPSCs were cultured in osteo/odontogenic induction medium. qPCR and Western blot analysis were performed to detect osteo/odonto-specific genes/proteins expression as well as the expression of EMILIN-1. After knockdown of Emilin-1 in hDPSCs with small interfering RNA and exogenous addition of recombinant human EMILIN-1 protein (rhEMILIN-1), Cell Counting Kit-8 assay, alkaline phosphatase staining, alizarin red S staining, qPCR and Western blot were performed to examine the effect of EMILIN-1 on proliferation and osteo/odontogenic differentiation of hDPSCs.

RESULTS

During the osteo/odontogenic induction of hDPSCs, the expression of osteo/odonto-specific genes/proteins increased, as did EMILIN-1 protein levels. More notably, knockdown of Emilin-1 decreased hDPSCs proliferation and osteo/odontogenic differentiation, whereas exogenous addition of rhEMILIN-1 increased them.

CONCLUSIONS

These findings suggested that EMILIN-1 is essential for the osteo/odontogenic differentiation of hDPSCs, which may provide new insights for teeth and bone tissue regeneration.

Naringenin stimulates osteogenic/odontogenic differentiation and migration of human dental pulp stem cells

Background/purpose

Naringenin, a naturally occurring flavanone in citrus fruits, regulates bone formation by bone marrow-derived mesenchymal stem cells. The purpose of this study was to characterize the effects of naringenin on some biological behaviors of human dental pulp stem cells (HDPSCs).

Materials and methods

HDPSCs were cultured in osteogenic differentiation medium and osteo/odontogenic differentiation and mineralization were analyzed by alkaline phosphatase (ALP) staining and Alizarin Red S (ARS) staining. The migration of HDPSCs was evaluated by transwell chemotactic migration assays and scratch wound healing migration assay. Using tooth slice/scaffold model, we assessed the in vivo odontogenic differentiation potential of HDPSCs.

Results

We have demonstrated that naringenin increases the osteogenic/odontogenic differentiation of HDPSCs through regulation of osteogenic-related proteins and the migratory ability of HDPSCs through stromal cell derived factor-1 (SDF-1)/C-X-C chemokine receptor type 4 (CXCR4) axis. Moreover, naringenin promotes the expression of dentin matrix acidic phosphoprotein-1 (DMP-1) and dentin sialophosphoprotein (DSPP) in HDPSCs seeded on tooth slice/scaffolds that are subcutaneously implanted into immunodeficient mice.

Conclusion

Our present study suggests that naringenin promotes migration and osteogenic/odontogenic differentiation of HDPSCs and may serve as a promising candidate in dental tissue engineering and bone regeneration.