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.

Rat hair follicle stem cells differentiate and promote recovery following spinal cord injury

Emerging studies of treating spinal cord injury （SCI） with adult stem cells led us to evaluate the effects of transplantation of hair follicle stem cells in rats with a compression-induced spinal cord lesion. Here, we proposed a hypothesis that rat hair follicle stem cell transplantation can promote the recovery of injured spinal cord. Compression-induced spinal cord injury was induced in Wistar rats in this study. The bulge area of the rat vibdssa follicles was isolated, cultivated and characterized with nestin as a stem cell marker. 5-Bromo-2＇-deoxyuridine （BrdU） labeled bulge stem cells were transplanted into rats with spinal cord injury. Immunohistochemical staining results showed that some of the grafted cells could survive and differentiate into oligodendrocytes （receptor-interacting protein positive cells） and neuronal-like cells （~lll-tubulin positive cells） at 3 weeks after transplantation. In addition, recovery of hind limb locomotor function in spinal cord injury rats at 8 weeks following cell transplantation was assessed using the Basso, Beattie and Bresnahan （BBB） locomotor rating scale. The results demon- strate that the grafted hair follicle stem cells can survive for a long time period in vivo and differentiate into neuronal- and glial-like cells. These results suggest that hair follicle stem cells can promote the recovery of spinal cord injury.

TGF-β2 downregulates osteogenesis under inflammatory conditions in dental follicle stem cells

Bone formation is important for the reconstruction of bone-related structures in areas that have been damaged by inflammation.Inflammatory conditions such as those that occur in patients with rheumatoid arthritis, cystic fibrosis, and periodontitis have been shown to inhibit osteoblastic differentiation. This study focussed on dental follicle stem cells(DFSCs), which are found in developing tooth germ and participate in the reconstruction of alveolar bone and periodontal tissue in periodontal disease. After bacterial infection of inflamed dental tissue, the destruction of bone was observed. Currently, little is known about the relationship between the inflammatory environment and bone formation. Osteogenic differentiation of inflamed DFSCs resulted in decreased alkaline phosphatase(ALP) activity and alizarin red S staining compared to normal DFSCs. Additionally, in vivo transplantation of inflamed and normal DFSCs demonstrated severe impairment of osteogenesis by inflamed DFSCs. Protein profile analysis via liquid chromatography coupled with tandem mass spectrometry was performed to analyse the differences in protein expression in inflamed and normal tissue. Comparison of inflamed and normal DFSCs showed significant changes in the level of expression of transforming growth factor(TGF)-β2. Porphyromonas gingivalis(P.g.)-derived lipopolysaccharide(LPS) was used to create in vitro inflammatory conditions similar to periodontitis. The osteogenic differentiation of LPS-treated DFSCs was suppressed, and the cells displayed low levels of TGF-β1 and high levels of TGF-β2. DFSCs treated with TGF-β2 inhibitors showed significant increases in alizarin red S staining and ALP activity. TGF-β1 expression was also increased after inhibition of TGF-β2. By examining inflamed DFSCs and LPS-triggered DFSCs, these studies showed both clinically and experimentally that the increase in TGF-β2 levels that occurs under inflammatory conditions inhibits bone formation.

Constructing skin-equivalents using hair follicle stem cells

Objective： To establish the method of constructing skin-equivalents （SE） using hair follicle stem cells （HFSC）. Methods： K19 positive cells derived from hair were cultivated using serum-free medium KGM and seeded on dermal equivalents （DE）. After the culture between the air-liquid interface for 14 days, SE were harvested and used for evaluation. Results： K19 positive cells chosen as HFSC were located in bulge of out root sheet in hair follicle. Cultivated HFSC could build a fully developed, multi-layered epidermis on the basis of DE, resembling the skin structure. Conclusion： HFSC located in out root sheet can differentiate into kerafinocyte in vitro and be used for SE construction.

Recent progress in hair follicle stem cell markers and their regulatory roles

Hair follicle stem cells(HFSCs)in the bulge are a multipotent adult stem cell population.They can periodically give rise to new HFs and even regenerate the epidermis and sebaceous glands during wound healing.An increasing number of biomarkers have been used to isolate,label,and trace HFSCs in recent years.Considering more detailed data from single-cell transcriptomics technology,we mainly focus on the important HFSC molecular markers and their regulatory roles in this review.

Future application of hair follicle stem cells： capable in differentiation into sweat gland cells

Background Sweat glands （SGs） can not regenerate after complete destruction in the severe skin injury, so it is important to find a ideal stem cell source in order to regenerate functional SGs. Hair follicle stem cells （HFSCs） possess the obvious properties of the adult stem cells, which are multipotent and easily accessible. In this research, we attempted to direct the HFSCs suffered from the sweat gland cells （SGCs） special differentiation by a cooperative co- culture system in vitro. Methods The designed co-culture microenvironment in the transwell was consist of two critial factors： heat shocked SGCs and dermis-like mesenchymal tissue, which appeared independently in the two control groups; after induction, the purified induced SGC-like cells were transplanted into the full-thickness scalded wounds of the nude mice, after 4 weeks, the reconstructed SG-like structures were identified by immunohistochemical and immunofluorescence analysis. Results A part of HFSCs in experimental group finally expressed SGCs phenotypes, by contrast, the control group 1 which just containing dermis-like mesenchymal tissue failed and the control group 2 consisted of heat shocked SGCs was in a poor efficiency; by immunofluorescence staining and flow cytometry analysis, the expression of HFSCs special biomarkers was down regulated, instead of the positive efficiency of SGCs special antigens increased; besides, the induced SGCs displayed a high expression of ectodysplasin A （EDA） and ectodysplasin A receptor （EDAR） genes and proteins; after cell transplantation, the youngest SG-like structures formed and be positive in SGCs special antigens, which never happened in untreated wounds （P 〈0.05）. Conclusion The HFSCs are multipotential and capable in differentiating into SGCs which promise a potential stem cells reservoir for future use; our special co-culture microenvironment is promising for HFSCs differentiating; the induced SGCs are functional and could work well in the regeneration of SGs.

Regulation of signaling pathways in hair follicle stem cells

Hair follicle stem cells(HFSCs)reside in the bulge region of the outer root sheath of the hair follicle.They are considered slow-cycling cells that are endowed with multilineage differentiation potential and superior proliferative capacity.The normal morphology and periodic growth of HFSCs play a significant role in normal skin functions,wound repair and skin regeneration.The HFSCs involved in these pathophysiological processes are regulated by a series of cell signal transduction pathways,such as lymphoid enhancer factor/T-cell factor,Wnt/β-catenin,transforming growth factor-β/bone morphogenetic protein,Notch and Hedgehog.The mechanisms of the interactions among these signaling pathways and their regulatory effects on HFSCs have been previously studied,but many mechanisms are still unclear.This article reviews the regulation of hair follicles,HFSCs and related signaling pathways,with the aims of summarizing previous research results,revealing the regulatory mechanisms of HFSC proliferation and differentiation and providing important references and new ideas for treating clinical diseases.

Oocyte-like cells induced from CD34-positive mouse hair follicle stem cells in vitro

Adult stem cells have been identified in a variety of mammalian organs including skin, hair follicles, pancreas, and bone marrow （Kruse et al., 2004）. These stem cells reside in a specific cellular environment where they remain in an undifferentiated state （Theise, 2006）. In addition, they are generally considered to be mul- tipotent, possessing the capacity to generate multiple cell types within the tissue, and thus play an important role in tissue mainte- nance and regeneration.

Modulation of Wnt/β-catenin signaling affects the directional differentiation of hair follicle stem cells

Aim:The differentiation of hair follicle stem cells(HFSCs)into hair follicle cells has potential clinical applications for cutaneous burns.However,the mechanisms regulating the differentiation of HFSCs into hair follicular papilla or epidermal cells are currently not clear.This study investigated the role of the Wnt/β-catenin pathway and its crosstalk with other signaling components during this differentiation process.Methods:Lithium chloride(LiCl,10 mmol/L)and keratinocyte growth factor(KGF,10μg/L)were used to induce HFSC differentiation,validated by immunofluorescence analysis.The mRNA expression ofβ-catenin,adenomatous polyposis coli,glycogen synthase kinase-3β(GSK-3β),axin,and lymphoid enhancer factor-1 after 3,5,7,and 9 days were measured to evaluate the role of the Wnt/β-catenin pathway.Results:During LiCl-induced HFSC differentiation into hair follicle cells,the Wnt/β-catenin signaling pathway was activated and the expression of GSK-3β,a vital component of the degradation compound,was inhibited.This led to increased cytoplasmicβ-catenin expression,nuclear translocation,and subsequent target gene transcription.By contrast,KGF induced the differentiation of HFSCs into epidermal cells and did not affect the expression ofβ-catenin.This data indicates that LiCl and KGF distinctly regulate the differentiation of HFSCs into hair follicle and epidermal cells,respectively.Furthermore,the Wnt/β-catenin signaling pathway is predominantly involved in hair follicle differentiation.Conclusion:these results demonstrate that LiCl can be used to differentiate HFSCs into hair follicle cells in vitro,which has important therapeutic applications for treating patients with cutaneous damage.

Follicle and melanocyte stem cells, and their application in neuroscience A Web of Science-based literature analysis

OBJECTIVE： To identify global research trends of follicle and melanocyte stem cells, and their application in neuroscience. DATA RETRIEVAL： We performed a bibliometric analysis of studies from 2002 to 2011 on follicle and melanocyte stem cells, and their application in neuroscience, which were retrieved from the Web of Science, using the key words follicle stem cell or melanocyte stem cell, and neural, neuro or nerve. SELECTION CRITERIA： Inclusion criteria： （a） peer-reviewed published articles on follicle and melanocyte stem cells, and their application in neuroscience, which were indexed in the Web of Science; （b） original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material, and news items. Exclusion criteria： （a） articles that required manual searching or telephone access; （b） documents that were not published in the public domain; and （c） a number of corrected papers from the total number of articles. MAIN OUTCOME MEASURES： （1） Distribution of publications on follicle and melanocyte stem cells by years, journals, countries, institutions, institutions in China, and most cited papers. （2） Distribution of publications on the application of follicle and melanocyte stem cells in neuroscience by years, journals, countries, institutions, and most cited papers. RESULTS： Of the 348 publications from 2002 to 2011 on follicle and melanocyte stem cells, which were retrieved from the Web of Science, more than half were from American authors and institutes. The most prolific institutions in China for publication of papers on follicle and melanocyte stem cells were the Fourth Military Medical University and Third Military Medical University. The most prolific journals for publication of papers on follicle and melanocyte stem cells were the Journal of Investigative Dermatology, Pigment Cell ＆ Melanoma Research. Of the 63 publications from 2002 to 2011 on the application of follicle and melanocyte stem cells in neuroscience, which were retrieved from the Web of Science, more than half were from American authors and institutes, and no papers were from Chinese authors and institutes. The most prolific journals for publication of papers on the application of follicle and melanocyte stem cells in neuroscience were the Journal of Investigative Dermatology, Pigment Cell ＆ Melanoma Research. CONCLUSION： Based on our analysis of the literature and research trends, we found that follicle stem cells might offer further benefits in neural regenerative medicine.

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.

A ROS-responsive hydrogel incorporated with dental follicle stem cell-derived small extracellular vesicles promotes dental pulp repair by ameliorating oxidative stress

Pulpitis,an inflammatory disease of dental pulp tissues,ultimately results in the loss of pulp defense properties.Existing clinical modalities cannot effectively promote inflamed pulp repair.Oxidative stress is a major obstacle inhibiting pulp repair.Due to their powerful antioxidative capacity,mesenchymal stem cell-derived small extracellular vesicles(MSC-sEVs)exhibit potential for treating oxidative stress-related disorders.However,whether MSC-sEVs shield dental pulp tissues from oxidative damage is largely unknown.Here,we showed that dental follicle stem cell-derived sEVs(DFSC-sEVs)have antioxidative and prohealing effects on a rat LPS-induced pulpitis model by enhancing the survival,proliferation and odontogenesis of H_(2)O_(2)-injured dental pulp stem cells(DPSCs).Additionally,DFSC-sEVs restored the oxidative/antioxidative balance in DPSC mitochondria and had comparable effects on ameliorating mitochondrial dysfunction with the mitochondrion-targeted antioxidant Mito-Tempo.To improve the efficacy of DFSC-sEVs,we fabricated an intelligent and injectable hydrogel to release DFSC-sEVs by combining sodium alginate(SA)and the ROS sensor RhB-AC.The newly formed SA-RhB hydrogel efficiently encapsulates DFSC-sEVs and exhibits controlled release of DFSC-sEVs in a HClO/ClO^(-)concentration-dependent manner,providing a synergistic antioxidant effect with DFSC-sEVs.These results suggest that DFSC-sEVs-loaded SA-RhB is a promising minimally invasive treatment for pulpitis by enhancing tissue repair in the pulp wound microenvironment.

Sustained delivery of rhMG53 promotes diabetic wound healing and hair follicle development

MG53 is an essential component of the cell membrane repair machinery,participating in the healing of dermal wounds.Here we develop a novel delivery system using recombinant human MG53(rhMG53)protein and a reactive oxygen species(ROS)-scavenging gel to treat diabetic wounds.Mice with ablation of MG53 display defective hair follicle structure,and topical application of rhMG53 can promote hair growth in the mg53/mice.Cell lineage tracing studies reveal a physiological function of MG53 in modulating the proliferation of hair follicle stem cells(HFSCs).We find that rhMG53 protects HFSCs from oxidative stress-induced apoptosis and stimulates differentiation of HSFCs into keratinocytes.The cytoprotective function of MG53 is mediated by STATs and MAPK signaling in HFSCs.The thermosensitive ROS-scavenging gel encapsulated with rhMG53 allows for sustained release of rhMG53 and promotes healing of chronic cutaneous wounds and hair follicle development in the db/db mice.These findings support the potential therapeutic value of using rhMG53 in combination with ROS-scavenging gel to treat diabetic wounds.