An overview of autophagy in the differentiation of dental stem cells

Dental stem cells(DSCs)have attracted significant interest as autologous stem cells since they are easily accessible and give a minimal immune response.These properties and their ability to both maintain self-renewal and undergo multi-lineage differentiation establish them as key players in regenerative medicine.While many regulatory factors determine the differentiation trajectory of DSCs,prior research has predominantly been based on genetic,epigenetic,and molecular aspects.Recent evidence suggests that DSC differentiation can also be influenced by autophagy,a highly conserved cellular process responsible for maintaining cellular and tissue homeostasis under various stress conditions.This comprehensive review endeavors to elucidate the intricate regulatory mechanism and relationship between autophagy and DSC differentiation.To achieve this goal,we dissect the intricacies of autophagy and its mechanisms.Subsequently,we elucidate its pivotal roles in impacting DSC differentiation,including osteo/odontogenic,neurogenic,and angiogenic trajectories.Furthermore,we reveal the regulatory factors that govern autophagy in DSC lineage commitment,including scaffold materials,pharmaceutical cues,and the extrinsic milieu.The implications of this review are far-reaching,underpinning the potential to wield autophagy as a regulatory tool to expedite DSC-directed differentiation and thereby promote the application of DSCs within the realm of regenerative medicine.

Clinical trials using dental stem cells:2022 update

For nearly 20 years,dental stem cells(DSCs)have been successfully isolated from mature/immature teeth and surrounding tissue,including dental pulp of permanent teeth and exfoliated deciduous teeth,periodontal ligaments,dental follicles,and gingival and apical papilla.They have several properties(such as self-renewal,multidirectional differentiation,and immunomodulation)and exhibit enormous potential for clinical applications.To date,many clinical articles and clinical trials using DSCs have reported the treatment of pulpitis,periapical lesions,periodontitis,cleft lip and palate,acute ischemic stroke,and so on,and DSC-based therapies obtained satisfactory effects in most clinical trials.In these studies,no adverse events were reported,which suggested the safety of DSC-based therapy.In this review,we outline the characteristics of DSCs and summ-arize clinical trials and their safety as DSC-based therapies.Meanwhile,we also present the current limitations and perspectives of DSC-based therapy(such as harvesting DSCs from inflamed tissue,applying DSC-conditioned medi-um/DSC-derived extracellular vesicles,and expanding-free strategies)to provide a theoretical basis for their clinical applications.

Application of dental stem cells in three-dimensional tissue regeneration

Dental stem cells can differentiate into different types of cells.Dental pulp stem cells,stem cells from human exfoliated deciduous teeth,periodontal ligament stem cells,stem cells from apical papilla,and dental follicle progenitor cells are five different types of dental stem cells that have been identified during different stages of tooth development.The availability of dental stem cells from discarded or removed teeth makes them promising candidates for tissue engineering.In recent years,three-dimensional(3D)tissue scaffolds have been used to reconstruct and restore different anatomical defects.With rapid advances in 3D tissue engineering,dental stem cells have been used in the regeneration of 3D engineered tissue.This review presents an overview of different types of dental stem cells used in 3D tissue regeneration,which are currently the most common type of stem cells used to treat human tissue conditions.

Proteomic profiling of various human dental stem cells-a systematic review

BACKGROUND The proteomic signature or profile best describes the functional component of a cell during its routine metabolic and survival activities.Additional complexity in differentiation and maturation is observed in stem/progenitor cells.The role of functional proteins at the cellular level has long been attributed to anatomical niches,and stem cells do not deflect from this attribution.Human dental stem cells(hDSCs),on the whole,are a combination of mesenchymal and epithelial coordinates observed throughout craniofacial bones to pulp.AIM To specify the proteomic profile and compare each type of hDSC with other mesenchymal stem cells(MSCs)of various niches.Furthermore,we analyzed the characteristics of the microenvironment and preconditioning changes associated with the proteomic profile of hDSCs and their influence on committed lineage differentiation.METHODS Literature searches were performed in PubMed,EMBASE,Scopus,and Web of Science databases,from January 1990 to December 2018.An extra inquiry of the grey literature was completed on Google Scholar,ProQuest,and OpenGrey.Relevant MeSH terms(PubMed)and keywords related to dental stem cells were used independently and in combination.RESULTS The initial search resulted in 134 articles.Of the 134 full-texts assessed,96 articles were excluded and 38 articles that met the eligibility criteria were reviewed.The overall assessment of hDSCs and other MSCs suggests that differences in the proteomic profile can be due to stem cellular complexity acquired from varied tissue sources during embryonic development.However,our comparison of the proteomic profile suffered inconsistencies due to the heterogeneity of various hDSCs.We believe that the existence of a heterogeneous population of stem cells at a given niche determines the modalities of regeneration or tissue repair.Added prominences to the differences present between various hDSCs have been reasoned out.CONCLUSION Systematic review on proteomic studies of various hDSCs are promising as an eye-opener for revisiting the proteomic profile and in-depth analysis to elucidate more refined mechanisms of hDSC functionalities.

Conditioned medium from human dental pulp stem cells treats spinal cord injury by inhibiting microglial pyroptosis

Human dental pulp stem cell transplantation has been shown to be an effective therapeutic strategy for spinal cord injury.However,whether the human dental pulp stem cell secretome can contribute to functional recovery after spinal cord injury remains unclear.In the present study,we established a rat model of spinal cord injury based on impact injury from a dropped weight and then intraperitoneally injected the rats with conditioned medium from human dental pulp stem cells.We found that the conditioned medium effectively promoted the recovery of sensory and motor functions in rats with spinal cord injury,decreased expression of the microglial pyroptosis markers NLRP3,GSDMD,caspase-1,and interleukin-1β,promoted axonal and myelin regeneration,and inhibited the formation of glial scars.In addition,in a lipopolysaccharide-induced BV2 microglia model,conditioned medium from human dental pulp stem cells protected cells from pyroptosis by inhibiting the NLRP3/caspase-1/interleukin-1βpathway.These results indicate that conditioned medium from human dental pulp stem cells can reduce microglial pyroptosis by inhibiting the NLRP3/caspase-1/interleukin-1βpathway,thereby promoting the recovery of neurological function after spinal cord injury.Therefore,conditioned medium from human dental pulp stem cells may become an alternative therapy for spinal cord injury.

RPLP0/TBP are the most stable reference genes for human dental pulp stem cells under osteogenic differentiation

BACKGROUND Validation of the reference gene(RG)stability during experimental analyses is essential for correct quantitative real-time polymerase chain reaction(RT-qPCR)data normalisation.Commonly,in an unreliable way,several studies use genes involved in essential cellular functions[glyceraldehyde-3-phosphate dehydro-genase(GAPDH),18S rRNA,andβ-actin]without paying attention to whether they are suitable for such experimental conditions or the reason for choosing such genes.Furthermore,such studies use only one gene when Minimum Information for Publication of Quantitative Real-Time PCR Experiments guidelines recom-mend two or more genes.It impacts the credibility of these studies and causes dis-tortions in the gene expression findings.For tissue engineering,the accuracy of gene expression drives the best experimental or therapeutical approaches.We cultivated DPSCs under two conditions:Undifferentiated and osteogenic dif-ferentiation,both for 35 d.We evaluated the gene expression of 10 candidates for RGs[ribosomal protein,large,P0(RPLP0),TATA-binding protein(TBP),GAPDH,actin beta(ACTB),tubulin(TUB),aminolevulinic acid synthase 1(ALAS1),tyro-sine 3-monooxygenase/tryptophan 5-monooxygenase activation protein,zeta(YWHAZ),eukaryotic translational elongation factor 1 alpha(EF1a),succinate dehydrogenase complex,subunit A,flavoprotein(SDHA),and beta-2-micro-globulin(B2M)]every 7 d(1,7,14,21,28,and 35 d)by RT-qPCR.The data were analysed by the four main algorithms,ΔCt method,geNorm,NormFinder,and BestKeeper and ranked by the RefFinder method.We subdivided the samples into eight subgroups.RESULTS All of the data sets from clonogenic and osteogenic samples were analysed using the RefFinder algorithm.The final ranking showed RPLP0/TBP as the two most stable RGs and TUB/B2M as the two least stable RGs.Either theΔCt method or NormFinder analysis showed TBP/RPLP0 as the two most stable genes.However,geNorm analysis showed RPLP0/EF1αin the first place.These algorithms’two least stable RGs were B2M/GAPDH.For BestKeeper,ALAS1 was ranked as the most stable RG,and SDHA as the least stable RG.The pair RPLP0/TBP was detected in most subgroups as the most stable RGs,following the RefFinfer ranking.CONCLUSION For the first time,we show that RPLP0/TBP are the most stable RGs,whereas TUB/B2M are unstable RGs for long-term osteogenic differentiation of human DPSCs in traditional monolayers.

Hepatocyte growth factor enhances the ability of dental pulp stem cells to ameliorate atherosclerosis in apolipoprotein E-knockout mice

BACKGROUND Atherosclerosis(AS),a chronic inflammatory disease of blood vessels,is a major contributor to cardiovascular disease.Dental pulp stem cells(DPSCs)are capable of exerting immunomodulatory and anti-inflammatory effects by secreting cytokines and exosomes and are widely used to treat autoimmune and inflam-mation-related diseases.Hepatocyte growth factor(HGF)is a pleiotropic cytokine that plays a key role in many inflammatory and autoimmune diseases.AIM To modify DPSCs with HGF(DPSC-HGF)and evaluate the therapeutic effect of DPSC-HGF on AS using an apolipoprotein E-knockout(ApoE-/-)mouse model and an in vitro cellular model.METHODS ApoE-/-mice were fed with a high-fat diet(HFD)for 12 wk and injected with DPSC-HGF or Ad-Null modified DPSCs(DPSC-Null)through tail vein at weeks 4,7,and 11,respectively,and the therapeutic efficacy and mechanisms were analyzed by histopathology,flow cytometry,lipid and glucose measurements,real-time reverse transcription polymerase chain reaction(RT-PCR),and enzyme-linked immunosorbent assay at the different time points of the experiment.An in vitro inflammatory cell model was established by using RAW264.7 cells and human aortic endothelial cells(HAOECs),and indirect co-cultured with supernatant of DPSC-Null(DPSC-Null-CM)or DPSC-HGF-CM,and the effect and mechanisms were analyzed by flow cytometry,RT-PCR and western blot.Nuclear factor-κB(NF-κB)activators and inhibitors were also used to validate the related signaling pathways.RESULTS DPSC-Null and DPSC-HGF treatments decreased the area of atherosclerotic plaques and reduced the expression of inflammatory factors,and the percentage of macrophages in the aorta,and DPSC-HGF treatment had more pronounced effects.DPSCs treatment had no effect on serum lipoprotein levels.The FACS results showed that DPSCs treatment reduced the percentages of monocytes,neutrophils,and M1 macrophages in the peripheral blood and spleen.DPSC-Null-CM and DPSC-HGF-CM reduced adhesion molecule expression in tumor necrosis factor-αstimulated HAOECs and regulated M1 polarization and inflammatory factor expression in lipopolysaccharide-induced RAW264.7 cells by inhibiting the NF-κB signaling pathway.CONCLUSION This study suggested that DPSC-HGF could more effectively ameliorate AS in ApoE-/-mice on a HFD,and could be of greater value in stem cell-based treatments for AS.

Self-assembly of differentiated dental pulp stem cells facilitates spheroid human dental organoid formation and prevascularization

BACKGROUND The self-assembly of solid organs from stem cells has the potential to greatly expand the applicability of regenerative medicine.Stem cells can self-organise into microsized organ units,partially modelling tissue function and regeneration.Dental pulp organoids have been used to recapitulate the processes of tooth development and related diseases.However,the lack of vasculature limits the utility of dental pulp organoids.AIM To improve survival and aid in recovery after stem cell transplantation,we demonstrated the three-dimensional(3D)self-assembly of adult stem cell-human dental pulp stem cells(hDPSCs)and endothelial cells(ECs)into a novel type of spheroid-shaped dental pulp organoid in vitro under hypoxia and conditioned medium(CM).METHODS During culture,primary hDPSCs were induced to differentiate into ECs by exposing them to a hypoxic environment and CM.The hypoxic pretreated hDPSCs were then mixed with ECs at specific ratios and conditioned in a 3D environment to produce prevascularized dental pulp organoids.The biological characteristics of the organoids were analysed,and the regulatory pathways associated with angiogenesis were studied.RESULTS The combination of these two agents resulted in prevascularized human dental pulp organoids(Vorganoids)that more closely resembled dental pulp tissue in terms of morphology and function.Single-cell RNA sequencing of dental pulp tissue and RNA sequencing of Vorganoids were integrated to analyse key regulatory pathways associated with angiogenesis.The biomarkers forkhead box protein O1 and fibroblast growth factor 2 were identified to be involved in the regulation of Vorganoids.CONCLUSION In this innovative study,we effectively established an in vitro model of Vorganoids and used it to elucidate new mechanisms of angiogenesis during regeneration,facilitating the development of clinical treatment strategies.

Human dental pulp stem/stromal cells in clinical practice

Dental pulp stem/stromal cells(DPSCs)are fibroblast-like,neural crest-derived,and multipotent cells that can differentiate into several lineages.They are relatively easy to isolate from healthy and inflamed pulps,with little ethical concerns and can be successfully cryopreserved and thawed.The therapeutic effects of DPSCs derived from animal or human sources have been extensively studied through in-vitro and in-vivo animal experiments and the findings indicated that DPSCs are effective not only for dental diseases but also for systemic diseases.Understanding that translational research is a critical step through which the fundamental scientific discoveries could be translated into applicable diagnostics and therapeutics that directly benefit humans,several clinical studies were carried out to generate evidence for the efficacy and safety of autogenous or allogeneic human DPSCs(hDPSCs)as a treatment modality for use in cell-based therapy,regenerative medicine/dentistry and tissue engineering.In clinical medicine,hDPSCs were effective for treating acute ischemic stroke and human exfoliated deciduous teeth-conditioned medium(SHED-CM)repaired vascular damage of the corpus cavernous,which is the main cause of erectile dysfunction.Whereas in clinical dentistry,autologous SHED was able to rege-nerate necrotic dental pulp after implantation into injured teeth,and micrografts enriched with autologous hDPSCs and collagen sponge were considered a treatment option for human intrabony defects.In contrast,hDPSCs did not add a significant regenerative effect when they were used for the treatment of post-extraction sockets.Large-scale clinical studies across diverse populations are still lacking to provide robust evidence on the safety and efficacy of hDPSCs as a new treatment option for various human diseases including dental-related problems.

Immunomodulatory properties of mesenchymal stem cells/dental stem cells and their therapeutic applications

Mesenchymal stem/stromal cells(MsCs)are widely distributed in the body and play essential roles in tissue regeneration and homeostasis.MsCs can be isolated from discarded tissues,expanded in vitro and used as therapeutics for autoimmune diseases and other chronic disorders.MsCs promote tissue regeneration and homeostasis by primarily acting on immune cells.At least six different types of MsCs have been isolated from postnatal dental tissues and have remarkable immunomodulatory properties.Dental stem cells(DsCs)have been demonstrated to have therapeutic effects on several systemic inflammatory diseases.Conversely,MsCs derived from nondental tissues such as the umbilical cord exhibit great benefits in the management of periodontitis in preclinical studies.Here,we discuss the main therapeutic uses of MSCs/DSCs,their mechanisms,extrinsic inflammatory cues and the intrinsic metabolic circuitries that govern the immunomodulatory functions of MSCs/DSCs.Increased understanding of the mechanisms underpinning the immunomodulatory functions of MSCs/DSCs is expected to aid in the development of more potent and precise MSC/DSC-based therapeutics.

Therapeutic and regenerative potential of different sources of mesenchymal stem cells for cardiovascular diseases

Mesenchymalstemcells(MSCs)areidealcandidatesfortreatingmanycardiovasculardiseases.MSCscanmodify the internal cardiac microenvironment to facilitate their immunomodulatory and differentiation abilities,which are essential to restore heart function.MSCs can be easily isolated from different sources,including bone marrow,adipose tissues,umbilical cord,and dental pulp.MSCs from various sources differ in their regenerative and therapeutic abilities for cardiovascular disorders.In this review,we will summarize the therapeutic potential of each MSC source for heart diseases and highlight the possible molecular mechanisms of each source to restore cardiac function.

Genetic modification of miR-34a enhances efficacy of transplanted human dental pulp stem cells after ischemic stroke

Human dental pulp stem cells(hDPSCs) promote recovery after ischemic stro ke;however,the therapeutic efficacy is limited by the poor survival of transplanted cells.For in vitro expe riments in the present study,we used oxygen-glucose deprivation/reoxygenation in hDPSCs to mimic cell damage induced by ischemia/reperfusion.We found that miRNA-34a-5p(miR-34a) was elevated under oxygen-glucose deprivation/reoxygenation conditions in hDPSCs.Inhibition of miR-34a facilitated the prolife ration and antioxidant capacity and reduced the apoptosis of hDPSCs.Moreove r,dual-luciferase reporter gene assay showed WNT1and SIRT1 as the targets of miR-34a.In miR-34a knockdown cell lines,WNT1 suppression reduced cell prolife ration,and SIRT1 suppression decreased the antioxidant capacity.Togethe r,these results indicated that miR-34a regulates cell prolife ration and antioxidant stress via targeting WNT1 and SIRT1,respectively.For in vivo expe riments,we injected genetically modified hDPSCs(anti34a-hDPSCs) into the brains of mice.We found that anti34a-hDPSCs significantly inhibited apoptosis,reduced cerebral edema and cerebral infarct volume,and improved motor function in mice.This study provides new insights into the molecular mechanism of the cell prolife ration and antioxidant capacity of hDPSCs,and suggests a potential gene that can be targeted to improve the survival rate and efficacy of transplanted hDPSCs in brain after ischemic stroke.

Clinical application prospects and transformation value of dental follicle stem cells in oral and neurological diseases

Since dental pulp stem cells(DPSCs)were first reported,six types of dental SCs(DSCs)have been isolated and identified.DSCs originating from the craniofacial neural crest exhibit dental-like tissue differentiation potential and neuroectodermal features.As a member of DSCs,dental follicle SCs(DFSCs)are the only cell type obtained at the early developing stage of the tooth prior to eruption.Dental follicle tissue has the distinct advantage of large tissue volume compared with other dental tissues,which is a prerequisite for obtaining a sufficient number of cells to meet the needs of clinical applications.Furthermore,DFSCs exhibit a significantly higher cell proliferation rate,higher colony-formation capacity,and more primitive and better anti-inflammatory effects than other DSCs.In this respect,DFSCs have the potential to be of great clinical significance and translational value in oral and neurological diseases,with natural advantages based on their origin.Lastly,cryopreservation preserves the biological properties of DFSCs and enables them to be used as off-shelf products for clinical applications.This review summarizes and comments on the properties,application potential,and clinical transformation value of DFSCs,thereby inspiring novel perspectives in the future treatment of oral and neurological diseases.

Dental pulp stem cells and banking of teeth as a lifesaving therapeutic vista

Exfoliated deciduous or an extracted healthy adult tooth can be used to harvest,process,and cryogenically preserve dental pulp stem cells.Future stem cell-based regenerative medicine methods could benefit significantly from these mesenchymal stem cells.Teeth serve as a substantial source of mesenchymal stem cells,otherwise disposed of as medical waste.Care should be taken to store this treasure trove of stem cells.Collective responsibility of patients,dentists,and physicians is necessary to ensure that this valuable resource is not wasted and that every possible dental pulp stem cell is available for use in the future.The dental pulp stem cells(DPSC)inside teeth represent a significant future source of stem cells for regenerative medicine procedures.This review describes the ontogeny,the laboratory processing and collection,and isolation methods of DPSC.This review also discusses currently available stem cell banking facilities and their potential use in regenerative medicine procedures in dental and general medical applications in the future.

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.

Wnt and BMP signaling crosstalk in regulating dental stem cells:Implications in dental tissue engineering

Tooth is a complex hard tissue organ and consists of multiple cell types that are regulated by important signaling pathways such as Wnt and BMP signaling.Serious injuries and/or loss of tooth or periodontal tissues may significantly impact aesthetic appearance,essential oral functions and the quality of life.Regenerative dentistry holds great promise in treating oral/dental disorders.The past decade has witnessed a rapid expansion of our understanding of the biological features of dental stem cells,along with the signaling mechanisms governing stem cell self-renewal and differentiation.In this review,we first summarize the biological characteristics of seven types of dental stem cells,including dental pulp stem cells,stem cells from apical papilla,stem cells from human exfoliated deciduous teeth,dental follicle precursor cells,periodontal ligament stem cells,alveolar bone-derived mesenchymal stem cells(MSCs),and MSCs from gingiva.We then focus on how these stem cells are regulated by bone morphogenetic protein(BMP)and/or Wnt signaling by examining the interplays between these pathways.Lastly,we analyze the current status of dental tissue engineering strategies that utilize oral/dental stem cells by harnessing the interplays between BMP and Wnt pathways.We also highlight the challenges that must be addressed before the dental stem cells may reach any clinical applications.Thus,we can expect to witness significant progresses to be made in regenerative dentistry in the coming decade.

KDM6B epigenetically regulates odontogenic differentiation of dental mesenchymal stem cells

Mesenchymal stem cells （MSCs） have been identified and isolated from dental tissues, including stem cells from apical papilla, which demonstrated the ability to differentiate into dentin-forming odontoblasts. The histone demethylase KDM6B （also known as JMJD3） was shown to play a key role in promoting osteogenic commitment by removing epigenetic marks H3K27me3 from the promoters of osteogenic genes. Whether KDM6B is involved in odontogenic differentiation of dental MSCs, however, is not known. Here, we explored the role of KDM6B in dental MSC fate determination into the odontogenic lineage. Using shRNA-expressing lentivirus, we performed KDM6B knockdown in dental MSCs and observed that KDM6B depletion leads to a significant reduction in alkaline phosphate （ALP） activity and in formation of mineralized nodules assessed by Alizarin Red staining. Additionally, mRNA expression of odontogenic marker gene SP7 （osterix, OSX）, as well as extracellular matrix genes BGLAP （osteoclacin, OCN） and SPP1 （osteopontin, OPN）, was suppressed by KDM6B depletion. When KDM6B was overexpressed in KDM6B-knockdown MSCs, odontogenic differentiation was restored, further confirming the facilitating role of KDM6B in odontogenic commitment. Mechanistically, KDM6B was recruited to bone morphogenic protein 2 （BMP2） promoters and the subsequent removal of silencing H3K27me3 marks led to the activation of this odontogenic master transcription gene. Taken together, our results demonstrated the critical role of a histone demethylase in the epigenetic regulation of odontogenic differentiation of dental MSCs. KDM6B may present as a potential therapeutic target in the regeneration of tooth structures and the repair of craniofacial defects.

Neurotrophic effects of dental pulp stem cells in repair of peripheral nerve after crush injury

BACKGROUND Nerve diseases and injuries,which are usually accompanied by motor or sensory dysfunction and disorder,impose a heavy burden upon patients and greatly reduce their quality of life.Dental pulp stem cells(DPSCs),derived from the neural crest,have many characteristics that are similar to those of neural cells,indicating that they can be an ideal source for neural repair.AIM To explore the potential roles and molecular mechanisms of DPSCs in crushed nerve recovery.METHODS DPSCs were isolated,cultured,and identified by multilineage differentiation and flow cytometry.Western blot and immunofluorescent staining were applied to analyze the expression levels of neurotrophic proteins in DPSCs after neural induction.Then,we collected the secretions of DPSCs.We analyzed their effects on RSC96 cell proliferation and migration by CCK8 and transwell assays.Finally,we generated a sciatic nerve crush injury model in vivo and used the sciatic function index,walking track analysis,muscle weight,and hematoxylin&eosin(H&E)staining to further evaluate the nerve repair ability of DPSCs.RESULTS DPSCs highly expressed several specific neural markers,including GFAP,S100,Nestin,P75,and NF200,and were inclined toward neural differentiation.Furthermore,neural-induced DPSCs(N-DPSCs)could express neurotrophic factors,including NGF,BDNF,and GDNF.The secretions of N-DPSCs could enhance the proliferation and migration of Schwann cells.In vivo,both DPSC and N-DPSC implants alleviated gastrocnemius muscle atrophy.However,in terms of anatomy and motor function,as shown by H&E staining,immunofluorescent staining,and walking track analyses,the repair effects of N-DPSCs were more sustained,potent,and effective than those of DPSCs and the controls.CONCLUSION In summary,this study demonstrated that DPSCs are inclined to differentiate into neural cells.N-DPSCs express neurotrophic proteins that could enhance the proliferation and migration of SCs.Furthermore,our results suggested that NDPSCs could help crushed nerves with functional recovery and anatomical repair in vivo.Thus,DPSCs or N-DPSCs could be a promising therapeutic cell source for peripheral nerve repair and regeneration.

Dental pulp stem cells express tendon markers under mechanical loading and are a potential cell source for tissue engineering of tendon-like tissue

Postnatal mesenchymal stem cells have the capacity to differentiate into multiple cell lineages. This study explored the possibility of dental pulp stem cells （DPSCs） for potential application in tendon tissue engineering. The expression of tendon- related markers such as scleraxis, tenascin-C, tenomodulin, eye absent homologue 2, collagens I and VI was detected in dental pulp tissue. Interestingly, under mechanical stimulation, these tendon-related markers were significantly enhanced when DPSCs were seeded in aligned polyglycolic acid （PGA） fibre scaffolds. Furthermore, mature tendon-like tissue was formed after transplantation of DPSC-PGA constructs under mechanical loading conditions in a mouse model. This study demonstrates that DPSCs could be a ootential stem cell source for tissue enEineerin~ of tendon-like tissue.

Epigenetic regulation of dental pulp stem cells and its potential in regenerative endodontics

Regenerative endodontics(RE)therapy means physiologically replacing damaged pulp tissue and regaining functional dentin–pulp complex.Current clinical RE procedures recruit endogenous stem cells from the apical papilla,periodontal tissue,bone marrow and peripheral blood,with or without application of scaffolds and growth factors in the root canal space,resulting in cementum-like and bone-like tissue formation.Without the involvement of dental pulp stem cells(DPSCs),it is unlikely that functional pulp regeneration can be achieved,even though acceptable repair can be acquired.DPSCs,due to their specific odontogenic potential,high proliferation,neurovascular property,and easy accessibility,are considered as the most eligible cell source for dentin–pulp regeneration.The regenerative potential of DPSCs has been demonstrated by recent clinical progress.DPSC transplantation following pulpectomy has successfully reconstructed neurovascularized pulp that simulates the physiological structure of natural pulp.The self-renewal,proliferation,and odontogenic differentiation of DPSCs are under the control of a cascade of transcription factors.Over recent decades,epigenetic modulations implicating histone modifications,DNA methylation,and noncoding(nc)RNAs have manifested as a new layer of gene regulation.These modulations exhibit a profound effect on the cellular activities of DPSCs.In this review,we offer an overview about epigenetic regulation of the fate of DPSCs;in particular,on the proliferation,odontogenic differentiation,angiogenesis,and neurogenesis.We emphasize recent discoveries of epigenetic molecules that can alter DPSC status and promote pulp regeneration through manipulation over epigenetic profiles.