A Review of Stem Cell Attributes Derived from the Oral Cavity.

Oral cavity stem cells (OCSCs) have been the focus of intense scientific efforts due to their accessibility and stem cell properties. The present work aims to compare the different characteristics of 6 types of dental stem cells derived from the oral cavity: dental pulp stem cells (DPSC), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSC), stem cells from the apical papilla (SCAP), bone marrow mesenchymal stem cells (BMSC), and gingival mesenchymal stem cells (GMSC). Using immunofluorescence and real-time polymerase chain reaction techniques, we analysed the cells for stem cell, differentiation, adhesion, and extracellular matrix markers; the ability to proliferate in vitro; and multilineage differentiation potential. Markers such as vimentin, CD44, alkaline phosphatase, CD146, CD271, CD49f, Oct 3/4, Sox 9, FGF7, nestin, and BMP4 showed significant differences in expression levels, highlighting the heterogeneity and unique characteristics of each cell type. At the same time, we confirmed that all cell types successfully differentiated into osteogenic, chondrogenic, or adipose lineages, with different readiness. In conclusion, our study reveals the distinct properties and potential applications of various dental-derived stem cells. These findings contribute to a deeper understanding of OCSCs and their significance in future clinical applications.

Fast and scarless: Prx1+ fibroblasts turbocharge healing.

Our oral cavity has evolved a capacity for rapid healing without scarring. In this issue of JEM, Ko et al. (2022. J. Exp. Med.https://doi.org/10.1084/jem.20221350) identify a Prx1+ fibroblast progenitor that drives oral regeneration by summoning pro-healing TGFß1+ macrophages.

The Review of Bioeffects of Static Magnetic Fields on the Oral Tissue-Derived Cells and Its Application in Regenerative Medicine.

Magnets have been widely used in dentistry for orthodontic tooth movement and denture retention. Nevertheless, criticisms have arisen regarding the biosafety of static magnetic field (SMF) effects on surrounding tissues. Various controversial pieces of evidence have been discussed regarding SMFs on cellular biophysics, but little consensus has been reached, especially in the field of dentistry. Thus, the present paper will first review the safe use of SMFs in the oral cavity and as an additive therapy to orthodontic tooth movement and periodontium regeneration. Then, studies regarding SMF-incorporated implants are reviewed to investigate the advantageous effects of SMFs on osseointegration and the underlying mechanisms. Finally, a review of current developments in dentistry surrounding the combination of magnetic nanoparticles (MNPs) and SMFs is made to clarify potential future clinical applications.

ZFP36 promotes VDR mRNA degradation to facilitate cell death in oral and colonic epithelial cells.

BACKGROUND: Vitamin D receptor (VDR) plays a vital protective role in oral and colonic epithelial cells. Albeit we know that VDR expression is reduced in the mucosal epithelial layers of autoimmune diseases, the mechanism by which VDR is decreased remains elusive. METHODS: VDR and zinc finger protein 36 (ZFP36) levels in human samples and cell lines were detected by real-time PCR, western blot and immunostaining. Luciferase report assay was used to test cis-elements in VDR gene promoter, real-time PCR was applied to measure mRNA decay and western blot was performed to evaluate protein degradation. RNA affinity chromatography assay was used to test protein-mRNA interaction. Co-immunoprecipitation was used to detect protein-protein interaction. The role of ZFP36 in AU-rich elements (AREs) in the 3' untranslated region (UTR) of VDR mRNA was also measured by luciferase report assay. RESULTS: We identify ZFP36 can bind with the AREs in the 3'UTR of VDR mRNA, leading to mRNA degradation in oral and colonic epithelial cells under inflammatory circumstance. Either ZFP36 protein or AREs of VDR mRNA mutation abolishes this protein-mRNA binding process. After the key amino acid's mutation, ZFP36 fails to decrease VDR mRNA expression. We also find that VDR physically binds with Y box-binding protein 1 (YBX-1) to block YBX-1's nuclear translocation and ameliorate cell death in the presence of inflammation. CONCLUSION: These findings provide insights into the cause of VDR decrease in oral and colonic epithelial cells under inflammatory condition and explain how VDR maintains cell viability in these cells. Video abstract.

Immunomodulatory functions of oral mesenchymal stem cells: Novel force for tissue regeneration and disease therapy.

Mesenchymal stem cells (MSCs)-based therapeutic strategies have achieved remarkable efficacies. Oral tissue-derived MSCs, with powerful self-renewal and multilineage differentiation abilities, possess the features of abundant sources and easy accessibility and hold great potential in tissue regeneration and disease therapies. Oral MSCs mainly consist of periodontal ligament stem cells, gingival mesenchymal stem cells, dental pulp stem cells, stem cells from human exfoliated deciduous teeth, stem cells from the apical papilla, dental follicle stem cells, and alveolar bone-derived mesenchymal stem. Early immunoinflammatory response stage is the prerequisite phase of healing process. Besides the potent capacities of differentiation and regeneration, oral MSCs are capable of interacting with various immune cells and function as immunomodulatory regulators. Consequently, the immunomodulatory effects of oral MSCs during damage repair seem to be crucial for exploring novel immunomodulatory strategies to achieve disease recovery and tissue regeneration. Herein, we reviewed various oral MSCs with their immunomodulatory properties and the potential mechanism, as well as their effects on immunomodulation-mediated disease therapies and tissue regeneration.

Multivalent Presentations of Glycomimetic Inhibitor of the Adhesion of Fungal Pathogen Candida albicans to Human Buccal Epithelial Cells.

Candida albicans causes some of the most prevalent hospital-acquired fungal infections, particularly threatening for immunocompromised patients. C. albicans strongly adheres to the surface of epithelial cells so that subsequent colonization and biofilm formation can take place. Divalent galactoside glycomimetic 1 was found to be a potent inhibitor of the adhesion of C. albicans to buccal epithelial cells. In this work, we explore the effect of multivalent presentations of glycomimetic 1 on its ability to inhibit yeast adhesion and biofilm formation. Tetra-, hexa-, and hexadecavalent displays of compound 1 were built on RAFT cyclopeptide- and polylysine-based scaffolds with a highly efficient and modular synthesis. Biological evaluation revealed that the scaffold choice significantly influences the activity of the lower valency conjugates, with compound 16, constructed on a tetravalent polylysine scaffold, found to inhibit the adhesion of C. albicans to human buccal epithelial cells more effectively than the glycomimetic 1; however, the latter performed better in the biofilm reduction assays. Interestingly, the higher valency glycoconjugates did not outperform the anti-adhesion activity of the original compound 1, and no significant effect of the core scaffold could be appreciated. SEM images of C. albicans cells treated with compounds 1, 14, and 16 revealed significant differences in the aggregation patterns of the yeast cells.

Differential Wnt-ß- catenin pathway activation in HPV positive and negative oral epithelium is transmitted during head and neck tumorigenesis: clinical implications.

The aim of this study is to understand the association of HPV infection and wnt-ß-catenin self-renewal pathway in development of head and neck squamous cell carcinoma (HNSCC). For this reason, the molecular profiles (methylation/deletion/expression) of antagonists (SFRP1/2 and DKK1), agonists (FZD7 and LRP6) and effector protein ß-catenin of the pathway were analyzed in HPV positive/negative oral epithelium at first, followed by its changes during development of the tumor along with correlations with different clinico-pathological parameters. HPV infection alone or in combination with tobacco habit could activate p- ß-catenin expression in basal/parabasal layers of oral epithelium through high expression of FZD7 and significant down regulation of SFRP1/2 through promoter hypermethylation due to over expression of DNMT1 with ubiquitous down regulation of DKK1 and up-regulation of LRP6. This phenomenon has been seen in respective HPV positive and negative HNSCC tumors with additional deletion/microsatellite size alterations in the antagonists. Overall alterations (methylation/deletion) of SFRP1/2, DKK1 gradually increased from Group I (HPV-/Tobacco-) to Group IV(HPV+/Tobacco+) tumors, leading to the worst prognosis of the patients. Thus, the transmission of differentially activated wnt-ß-catenin pathway from HPV positive/negative basal/parabasal layers of oral epithelium to HNSCC tumors determines differences in molecular pathogenesis of the disease.

Women rag pickers at a dump in Ahmedabad: Genotoxicity and oxidative stress.

Municipal solid waste (MSW) generated in Ahmedabad, India, and the surrounding area is dumped at the Pirana site; rag pickers collect materials for re-sale. We have compared genotoxicity and oxidative stress in samples from women rag pickers working at this site, with women involved only in door-to-door waste picking (in residential areas near the university campus) as "controls". The buccal Cytokinesis-Block Micronucleus (CBMN) assay showed significantly higher frequencies of Micronucleus (MN), Nucleoplasmic Bridges (NPB), and Nuclear Buds (NB) in the rag pickers than in the "controls". The buccal Micronuclei Cytome (BMCyt) assay showed significantly higher prevalence of nuclear anomalies, such as micronucleus, karyorrhexis, karyolytic cells, and nuclear buds. Blood samples from the rag pickers showed lower levels of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase), lower total serum protein concentrations, and greater lipid peroxidation compared to the "control" group. Exposure to hazardous solid waste may lead to increased oxidative damage and genotoxicity; improved safety procedures and the use of personal protective equipment are recommended.

Oral Neutrophils: Underestimated Players in Oral Cancer.

The composition of the oral milieu reflects oral health. Saliva provides an environment for multiple microorganisms, and contains soluble factors and immune cells. Neutrophils, which rapidly react on the changes in the microenvironment, are a major immune cell population in saliva and thus may serve as a biomarker for oral pathologies. This review focuses on salivary neutrophils in the oral cavity, their phenotype changes in physiological and pathological conditions, as well as on factors regulating oral neutrophil amount, activation and functionality, with special emphasis on oral cancer and its risk factors.

Establishment and validation of an in vitro co-culture model for oral cell lines using human PBMC-derived osteoclasts, osteoblasts, fibroblasts and keratinocytes.

Indirect co-culture models with osteoclasts including oral cell lines may be influenced by M-CSF and RANKL in the common cell medium. Therefore, we investigated the viability and proliferation of osteoblasts (OB), fibroblasts (FB) and oral keratinocytes (OK) under stratified medium modification and assessed the differentiation of osteoclasts in each co-culture. The impact of M-CSF and RANKL in the common OC co-culture was assessed for OB, FB and OK via MTT assay via DAPI control. The multinuclearity and function of OC were evaluated by light microscopy, DAPI staining, resorption assay and FACS analysis. The PBMC showed the highest differentiation into OC after an incubation period of 7 days. Furthermore, co-culture with OB enhanced the number of differentiated multinucleated OC in comparison with monoculture, whereas co-culture with OK decreased PBMC multinuclearity and OC differentiation. FB did not influence the number of differentiated OC in a co-culture. RANKL and M-CSF reduction had no impact on OC differentiation in co-culture with FB or OB, whereas this medium modification for OK attenuated PBMC multinuclearity and OC differentiation in all approaches. Supplementation of RANKL and M-CSF can be modified for a co-culture of PBMC with FB or OB without disturbing OC differentiation. Thus, pathogenic processes of bone remodelling involving OB, OC, FB and OK in the oral cavity can be investigated thoroughly.

Mouth opening is mediated by separation of dorsal and ventral daughter cells of the lip precursor cells in the larvacean, Oikopleura dioica.

Mouth formation involves the processes of mouth opening, formation of the oral cavity, and the development of associated sensory organs. In deuterostomes, the surface ectoderm and the anterior part of the archenteron are reconfigured and reconnected to make a mouth opening. This study of the larval development of the larvacean, Oikopleura dioica, investigates the cellular organization of the oral region, the developmental processes of the mouth, and the formation of associated sensory cells. O. dioica is a simple chordate whose larvae are transparent and have a small number of constituent cells. It completes organ morphogenesis in 7 h, between hatching 3 h after fertilization and the juvenile stage at 10 h, when it attains adult form and starts to feed. It has two types of mechanosensory cell embedded in the oral epithelium, which is a single layer of cells. There are twenty coronal sensory cells in the circumoral nerve ring and two dorsal sensory organ cells. Two bilateral lip precursor cells (LPCs), facing the anterior surface, divide dorsoventrally and make a wedge-shaped cleft between the two daughter cells named the dorsal lip cell (DLC) and the ventral lip cell (VLC). Eventually, the DLC and VLC become detached and separated into dorsal and ventral lips, triggering mouth opening. This is an intriguing example of cell division itself contributing to morphogenesis. The boundary between the ectoderm and endoderm is present between the lip cells and coronal sensory cells. All oral sensory cells, including dorsal sensory organ cells, were of endodermal origin and were not derived from the ectodermal placode. These observations on mouth formation provide a cellular basis for further studies at a molecular level, in this simple chordate.

Evaluation of the In Vitro Oral Wound Healing Effects of Pomegranate (Punica granatum) Rind Extract and Punicalagin, in Combination with Zn (II).

Pomegranate (Punica granatum) is a well-established folklore medicine, demonstrating benefits in treating numerous conditions partly due to its antimicrobial and anti-inflammatory properties. Such desirable medicinal capabilities are attributed to a high hydrolysable tannin content, especially punicalagin. However, few studies have evaluated the abilities of pomegranate to promote oral healing, during situations such as periodontal disease or trauma. Therefore, this study evaluated the antioxidant and in vitro gingival wound healing effects of pomegranate rind extract (PRE) and punicalagin, alone and in combination with Zn (II). In vitro antioxidant activities were studied using DPPH and ABTS assays, with total PRE phenolic content measured by Folin-Ciocalteu assay. PRE, punicalagin and Zn (II) combination effects on human gingival fibroblast viability/proliferation and migration were investigated by MTT assay and scratch wounds, respectively. Punicalagin demonstrated superior antioxidant capacities to PRE, although Zn (II) exerted no additional influences. PRE, punicalagin and Zn (II) reduced gingival fibroblast viability and migration at high concentrations, but retained viability at lower concentrations without Zn (II). Fibroblast speed and distance travelled during migration were also enhanced by punicalagin with Zn (II) at low concentrations. Therefore, punicalagin in combination with Zn (II) may promote certain anti-inflammatory and fibroblast responses to aid oral healing.

Therapeutic Functions of Stem Cells from Oral Cavity: An Update.

Adult stem cells have been developed as therapeutics for tissue regeneration and immune regulation due to their self-renewing, differentiating, and paracrine functions. Recently, a variety of adult stem cells from the oral cavity have been discovered, and these dental stem cells mostly exhibit the characteristics of mesenchymal stem cells (MSCs). Dental MSCs can be applied for the replacement of dental and oral tissues against various tissue-damaging conditions including dental caries, periodontitis, and oral cancers, as well as for systemic regulation of excessive inflammation in immune disorders, such as autoimmune diseases and hypersensitivity. Therefore, in this review, we summarized and updated the types of dental stem cells and their functions to exert therapeutic efficacy against diseases.

Corrosion Resistance of Graphene oxide/Silver Coatings on Ni-Ti alloy and Expression of IL-6 and IL-8 in Human Oral Fibroblasts.

Graphene based materials (GBMs) have potentials for dental and medical applications. GBMs may cause changes in the levels of cytokine released in the body. This study aimed to study the corrosion resistance of graphene oxide (GO) and GO/silver (GO/Ag) nanocomposite coated nickel-titanium (NiTi) alloy by electrophoretic deposition and to access the viability of human pulp fibroblasts, and the interleukin (IL)-6 and IL-8 expression level. The bare and coated NiTi samples were characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, surface profilometry, and X-ray diffraction (XRD). The corrosion resistance of the bare NiTi and coated NiTi samples were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy in 3.5% NaCl solution. The cell viability of human pulp fibroblasts was accessed by the treated culture medium of the bare NiTi and coated NiTi alloys containing 1% fetal bovine serum. IL-6 and IL-8 expression levels were studied by human enzyme-linked immunosorbent assay (ELISA). Data were analyzed using One-way ANOVA (α  =  0.05). Both the GO-coated NiTi and GO/Ag-coated NiTi alloys showed better corrosion resistance, a lower rate of corrosion, and higher protection efficiency than the bare NiTi alloy. The coated NiTi alloys were biocompatible to human pulp fibroblasts and showed upregulation of IL-6 and IL-8 levels.

Induction of p53 in keratinocyte cultures treated with Behçet's patient sera.

BACKGROUND: Behçet's disease (BD) is a rare, multisystem vasculitis disease characterized by recurrent orogenital ulcerations with its etiology remained unclear. The transcription factor p53 has been reported to be upregulated in some autoimmune diseases, such as lupus erythematosus, dermatomyositis, and psoriasis. However, little is known about its alteration in BD. METHODS: Keratinocyte cultures of both skin and oral origins were treated sera of 18 Behcet patients for 24 hours and analyzed by indirect immunofluorescence for p53 expression. The specificity of p53 expression was confirmed by siRNA-mediated p53 knockdown and the serum IgG removal studies. The expression of p53 levels was quantitatively analyzed with ImageJ. RESULTS: It was shown that the expression of p53 is increased in skin and oral keratinocyte cell lines, in both the nucleus and cytoplasm of cells treated with patient sera compared to controls. Either p53 knockdown or IgG removal results in a reduction of p53 levels relative to cells treated with patient sera without p53 knockdown or IgG depletion. CONCLUSIONS: This in vitro study provides the first evidence that BD sera can induce the p53 expression in keratinocytes that may have implications in Behcet pathogenesis.

Wheat germ agglutinin liposomes with surface grafted cyclodextrins as bioadhesive dual-drug delivery nanocarriers to treat oral cells.

Topical management of oral infection requires combined use of multiple classes of drugs and frequent dosing due to low drug retention rates. The sustained, co-delivery of drugs with different solubilities to cells using nanoparticle drug delivery systems remains a challenge. Here, we developed wheat germ agglutinin (WGA) conjugated liposomes with surface grafted cyclodextrin (WGA-liposome-CD) as bioadhesive dual-drug nanocarriers. We effectively encapsulated two physiochemically different drugs (ciprofloxacin and betamethasone) and demonstrated sustained co-drug release in saliva over a 24 h period in vitro. As proof of therapeutic utility in oral cells, we infected oral keratinocytes with Aggregatibacter actinomycetemcomitans, a bacterial pathogen responsible for chronic periodontal disease. Drug release, resulting from nanocarrier cell binding, produced a significant increase in oral cell survival and synergistically reduced inflammation. These results suggest that WGA-liposome-CD nanocarriers are novel cyto-adhesive candidates for delivering multiple drugs with sustained therapeutic activity for localized drug delivery to oral cells.

Metal nanoparticles-induced activation of NLRP3 inflammasome in human oral keratinocytes is a possible mechanism of oral lichenoid lesions.

The NLRP3 inflammasome has been implicated in the pathogenesis of various inflammatory diseases and is activated by particulate stimulants. Oral epithelial keratinocytes are frequently exposed to metal nanoparticles. In this study, we examined the effects of gold, silver, and palladium nanoparticles, which are frequently used for dental metal alloys on cell proliferation, cytotoxicity, autophagy, lysosomal functions, and NLRP3 inflammasome activation using the immortalized human oral keratinocyte cell line RT-7. The metal nanoparticles were agglomerated in the membrane vesicles in RT-7 cells and suppressed cell proliferation and increased lactate dehydrogenase activity as well as the proportion of apoptotic cells. Silver and palladium nanoparticles induced autophagy and lysosomal dysfunctions and all metal nanoparticles tested triggered the secretion of IL-1ß through caspase-1 activation. Furthermore, the epithelium obtained from patients with oral lichenoid lesions (OLLs) had robust NLRP3, ASC, caspase-1, and IL-1ß-positive keratinocytes and cDNA microarray showed significant elevation in the mRNA levels of NLRP3. These results suggest that internalized metal nanoparticles in oral mucosal epithelial cells activate the NLRP3 inflammasome through the induction of lysosomal damage and autophagy dysfunction. This process may be involved in the pathogenesis of OLL and suggest its potential as an alternative target for OLL therapy.

A CRISPR/Cas9-based strategy to simultaneously inactivate the entire ALS gene family in Candida orthopsilosis.

Aim: In this study, the CRISPR gene-editing approach was used to simultaneously inactivate all three members of the ALS gene family in the opportunistic pathogen Candida orthopsilosis. Materials & methods: Using a single gRNA and repair template, CRISPR-edited clones were successfully generated in a one-step process in both C. orthopsilosis reference and clinical strains. Results: The phenotypic characterization of the ALS triple-edited strains revealed no impact on growth in liquid or solid media. However, pseudohyphal formation and the ability to adhere to human buccal epithelial cells were significantly decreased in triple-edited clones. Conclusion: Our CRISPR/Cas9 system is a powerful tool for simultaneous editing of fungal gene families, which greatly accelerates the generation of multiple gene-edited Candida strains. Data deposition: Nucleotide sequence data are available in the GenBank databases under the accession numbers MK875971, MK875972, MK875973, MK875974, MK875975, MK875976, MK875977.