AFF4 regulates osteogenic differentiation of human dental follicle cells

As a member of the AFF(AF4/FMR2)family,AFF4 is a transcription elongation factor that is a component of the super elongation complex.AFF4 serves as a scaffolding protein that connects transcription factors and promotes gene transcription through elongation and chromatin remodelling.Here,we investigated the effect of AFF4 on human dental follicle cells(DFCs)in osteogenic differentiation.In this study,we found that small interfering RNA-mediated depletion of AFF4 resulted in decreased alkaline phosphatase(ALP)activity and impaired mineralization.In addition,the expression of osteogenic-related genes(DLX5,SP7,RUNX2 and BGLAP)was significantly downregulated.In contrast,lentivirus-mediated overexpression of AFF4 significantly enhanced the osteogenic potential of human DFCs.Mechanistically,we found that both the mRNA and protein levels of ALKBH1,a critical regulator of epigenetics,changed in accordance with AFF4 expression levels.Overexpression of ALKBH1 in AFF4-depleted DFCs partially rescued the impairment of osteogenic differentiation.Our data indicated that AFF4 promoted the osteogenic differentiation of DFCs by upregulating the transcription of ALKBH1.

circ_0003204 regulates the osteogenic differentiation of human adipose-derived stem cells via miR-370-3p/HDAC4 axis

Human adipose-derived stem cells(hASCs)are a promising cell type for bone tissue regeneration.Circular RNAs(circRNAs)have been shown to play a critical role in regulating various cell differentiation and involve in mesenchymal stem cell osteogenesis.However,how circRNAs regulate hASCs in osteogenesis is still unclear.Herein,we found circ_0003204 was significantly downregulated during osteogenic differentiation of hASCs.Knockdown of circ_0003204 by si RNA or overexpression by lentivirus confirmed circ_0003204 could negatively regulate the osteogenic differentiation of hASCs.We performed dual-luciferase reporting assay and rescue experiments to verify circ_0003204 regulated osteogenic differentiation via sponging miR-370-3p.We predicted and confirmed that miR-370-3p had targets in the 3′-UTR of HDAC4 m RNA.The following rescue experiments indicated that circ_0003204 regulated the osteogenic differentiation of hASCs via miR-370-3p/HDAC4 axis.Subsequent in vivo experiments showed the silencing of circ_0003204 increased the bone formation and promoted the expression of osteogenic-related proteins in a mouse bone defect model,while overexpression of circ_0003204 inhibited bone defect repair.Our findings indicated that circ_0003204 might be a promising target to promote the efficacy of hASCs in repairing bone defects.

Common dental diseases in children and malocclusion

Malocclusion is a worldwide dental problem that influences the affected individuals to varying degrees. Many factors contribute to the anomaly in dentition, including hereditary and environmental aspects. Dental caries, pulpal and periapical lesions, dental trauma, abnormality of development, and oral habits are most common dental diseases in children that strongly relate to malocclusion. Management of oral health in the early childhood stage is carried out in clinic work of pediatric dentistry to minimize the unwanted effect of these diseases on dentition. This article highlights these diseases and their impacts on malocclusion in sequence. Prevention, treatment, and management of these conditions are also illustrated in order to achieve successful oral health for children and adolescents, even for their adult stage.

Salivary proteins and microbiota as biomarkers for early childhood caries risk assessment

Early childhood caries （ECC） is a term used to describe dental caries in children aged 6 years or younger. Oral streptococci, such as Streptococcus mutans and Streptococcus sorbrinus, are considered to be the main etiological agents of tooth decay in children. Other bacteria, such as Prevotella spp. and Lactobacillus spp., and fungus, that is, Candida albicans, are related to the development and progression of ECC. Biomolecules in saliva, mainly proteins, affect the survival of oral microorganisms by multiple innate defensive mechanisms, thus modulating the oral microflora. Therefore, the protein composition of saliva can be a sensitive indicator for dental health. Resistance or susceptibility to caries may be significantly correlated with alterations in salivary protein components. Some oral microorganisms and saliva proteins may serve as useful biomarkers in predicting the risk and prognosis of caries. Current research has generated abundant information that contributes to a better understanding of the roles of microorganisms and salivary proteins in ECC occurrence and prevention. This review summarizes the microorganisms that cause caries and tooth-protective salivary proteins with their potential as functional biomarkers for ECC risk assessment. The identification of biomarkers for children at high risk of ECC is not only critical for early diagnosis but also important for preventing and treating the disease.

Berberine mediates root remodeling in an immature tooth with apical periodontitis by regulating stem cells from apical papilla differentiation

Once pulp necrosis or apical periodontitis occurs on immature teeth,the weak root and open root apex are challenging to clinicians.Berberine(BBR)is a potential medicine for bone disorders,therefore,we proposed to apply BBR in root canals to enhance root repair in immature teeth.An in vivo model of immature teeth with apical periodontitis was established in rats,and root canals were filled with BBR,calcium hydroxide or sterilized saline for 3 weeks.The shape of the roots was analyzed by micro-computed tomography and histological staining.In vitro,BBR was introduced into stem cells from apical papilla(SCAPs).Osteogenic differentiation of stem cells from apical papilla was investigated by alkaline phosphatase activity,mineralization ability,and gene expression of osteogenic makers.The signaling pathway,which regulated the osteogenesis of SCAPs was evaluated by quantitative real time PCR,Western blot analysis,and immunofluorescence.In rats treated with BBR,more tissue was formed,with longer roots,thicker root walls,and smaller apex diameters.In addition,we found that BBR promoted SCAPs osteogenesis in a time-dependent and concentration-dependent manner.BBR induced the expression ofβ-catenin and enhancedβ-catenin entering into the nucleus,to up-regulate more runt-related nuclear factor 2 downstream.BBR enhanced root repair in immature teeth with apical periodontitis by activating the canonical Wnt/β-catenin pathway in SCAPs.

New insight into dental epithelial stem cells:Identification,regulation,and function in tooth homeostasis and repair

Tooth enamel,a highly mineralized tissue covering the outermost area of teeth,is always damaged by dental caries or trauma.Tooth enamel rarely repairs or renews itself,due to the loss of ameloblasts and dental epithelial stem cells(DESCs)once the tooth erupts.Unlike human teeth,mouse incisors grow continuously due to the presence of DESCs that generate enamel-producing ameloblasts and other supporting dental epithelial lineages.The ready accessibility of mouse DESCs and wide availability of related transgenic mouse lines make mouse incisors an excellent model to examine the identity and heterogeneity of dental epithelial stem/progenitor cells;explore the regulatory mechanisms underlying enamel formation;and help answer the open question regarding the therapeutic development of enamel engineering.In the present review,we update the current understanding about the identification of DESCs in mouse incisors and summarize the regulatory mechanisms of enamel formation driven by DESCs.The roles of DESCs during homeostasis and repair are also discussed,which should improve our knowledge regarding enamel tissue engineering.