The Cytokine TGF-ß Induces Interleukin-31 Expression from Dermal Dendritic Cells to Activate Sensory Neurons and Stimulate Wound Itching.

Cutaneous wound healing is associated with the unpleasant sensation of itching. Here we investigated the mechanisms underlying this type of itch, focusing on the contribution of soluble factors released during healing. We found high amounts of interleukin 31 (IL-31) in skin wound tissue during the peak of itch responses. Il31-/- mice lacked wound-induced itch responses. IL-31 was released by dermal conventional type 2 dendritic cells (cDC2s) recruited to wounds and increased itch sensory neuron sensitivity. Transfer of cDC2s isolated from late-stage wounds into healthy skin was sufficient to induce itching in a manner dependent on IL-31 expression. Addition of the cytokine TGF-ß1, which promotes wound healing, to dermal DCs in vitro was sufficient to induce Il31 expression, and Tgfbr1f/f CD11c-Cre mice exhibited reduced scratching and decreased Il31 expression in wounds in vivo. Thus, cDC2s promote itching during skin would healing via a TGF-ß-IL-31 axis with implications for treatment of wound itching.

High Glucose Intake Exacerbates Autoimmunity through Reactive-Oxygen-Species-Mediated TGF-ß Cytokine Activation.

Diet has been suggested to be a potential environmental risk factor for the increasing incidence of autoimmune diseases, yet the underlying mechanisms remain elusive. Here, we show that high glucose intake exacerbated autoimmunity in mouse models of colitis and experimental autoimmune encephalomyelitis (EAE). We elucidated that high amounts of glucose specifically promoted T helper-17 (Th17) cell differentiation by activating transforming growth factor-ß (TGF-ß) from its latent form through upregulation of reactive oxygen species (ROS) in T cells. We further determined that mitochondrial ROS (mtROS) are key for high glucose-induced TGF-ß activation and Th17 cell generation. We have thus revealed a previously unrecognized mechanism underlying the adverse effects of high glucose intake in the pathogenesis of autoimmunity and inflammation.

Fructose Potentiates Bone Loss and Marrow Adipose Tissue Accumulation by Inhibiting Adenosine 5'-Monophosphate-Activated Protein Kinase in Mesenchymal Stem Cells.

Increased fructose consumption has been elucidated to contribute to metabolic diseases. Bone is a dynamic organ that undergoes constant remodeling. However, the effects of fructose on bone health are still in dispute. Here, we identified fructose deteriorated bone mineral density while promoting the abundance of bone marrow adipose tissue. Fructose remarkably promoted the bone marrow mesenchymal stem cells' (BMMSCs) adipogenic commitment at the expense of osteogenic commitment. Fructose boosted the glycolysis of BMMSCs and inhibited phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK), which played a crucial role in bone-fat alteration. Our results suggested that fructose potentiated bone loss and marrow adipose tissue accumulation by suppressing AMPK activation in BMMSCs. Understanding fructose which affected bone metabolism was thus of primary importance in order to establish preventative measures or treatments for this condition.

Hydrogen Sulfide Attenuates Mesenchymal Stem Cell Aging Progress via the Calcineurin-NFAT Signaling Pathway.

Aging is a gradual process that is coupled with a decline in the regenerative capacity of stem cells and a subsequent reduction in tissue function and repair. Hydrogen sulfide (H2S) plays an important role in maintaining the function of stem cells. The present study aimed to investigate the role of H2S in mesenchymal stem cell aging and the underlying mechanism and to provide novel insights into stem cell therapies in elderly people. Bone marrow mesenchymal stem cells (BMMSCs) were isolated from young mice (2 months) and from old mice (12 months). Senescence-associated ß-galactosidase (SA-ß-Gal) activity, reactive oxygen species (ROS) production, ROS scavenging enzymes, and the expression of cell-cycle-related genes were compared between those young and old BMMSCs. The expression of H2S-producing enzymes and the production of H2S in BMMSCs were examined. In vitro osteogenic differentiation and cell senescence were analyzed in young and old BMMSCs before and after H2S treatment. The underlying mechanism was investigated using calcineurin and NFAT1 inhibitors or a Foxp3 siRNA. Bone volume/tissue volume (BV/TV) of femurs in mice was examined using micro-CT with or without systemic injection of an H2S donor. Here, we found that H2S levels in BMMSCs declined with age. When the generation of H2S was blocked with the CBS inhibitor hydroxylamine and the CSE inhibitor dl-propargylglycine, BMMSCs underwent senescence. The elevation of H2S levels rescued BMMSC function in vitro and prevented bone loss in vivo. Mechanistically, H2S represses cell aging via the calcineurin-NFAT1 signaling pathway.

Advances in the Study of Extracellular Vesicles for Bone Regeneration.

Promoting the efficiency of bone regeneration in bone loss diseases is a significant clinical challenge. Traditional therapies often fail to achieve better therapeutic outcomes and shorter treatment times. However, in recent years, extracellular vesicles (EVs) have gained significant attention due to their exceptional osteogenic function in bone regeneration and superior therapeutic effects compared to traditional cell therapy. EVs have emerged as a promising therapy for tissue defect regeneration due to their various physiological functions, such as regulating the immune response and promoting tissue repair and regeneration. Moreover, EVs have good biocompatibility, low immunogenicity, and long-term stability, and can be improved through pretreatment and other methods. Studies investigating the mechanisms by which extracellular vesicles promote bone regeneration and applying EVs from different sources using various methods to animal models of bone defects have increased. Therefore, this paper reviews the types of EVs used for bone regeneration, their sources, roles, delivery pathways, scaffold biomaterials, and applications.

Risk prediction model of impacted supernumerary tooth-associated root resorption in children based on cone-beam computed tomography analysis: a case control study.

BACKGROUND: External surface resorption is pressure-induced resorption and occurs on the external surface of the root, pressure exerted by impacted teeth, is common causes of external surface resorption. Predictive risk factors of impacted supernumerary tooth-associated root resorption (ISTARR) mentioned in this article include supernumerary teeth and patient factors. To investigate the risk factors of impacted supernumerary tooth-associated root resorption and predict the incidence of root resorption. METHODS: This restrospective study enrolled 324 patients with impacted supernumerary tooth. All Cone-Beam Computed Tomography (CBCT) data and patient information were divided into two groups (without tooth root resorption and with root resorption). CBCT images and patient information (age and gender) of 133 patients had adjacent tooth root resorption and 191 did not. seven variables were analysed using binary logistic regression. RESULTS: Individual analysis of potential risk factors showed that age, crown mesiodistal direction, root formation, and odontotheca of the impacted supernumerary tooth were associated significantly with ISTARR. Binary logistic regression showed that impacted supernumerary tooth with odontotheca (Odd Ratio = 2.926), the crown is in the middle (Odd Ratio = 1.446), located at the middle third of the adjacent tooth root (Odd Ratio = 1.614), complete root development (Odd Ratio = 1.334), and patient's age (Odd Ratio = 1.261) were significantly associated with ISTARR risk. CONCLUSIONS: The risk factors of root resorption can be detected and predicted early according to the features of supernumerary tooth and patient's age. Still, more prospective studies with larger sample size are needed to validate the result.

The impacts of oral and gut microbiota on alveolar bone loss in periodontitis.

Periodontitis, a chronic infectious disease, primarily arises from infections and the invasion of periodontal pathogens. This condition is typified by alveolar bone loss resulting from host immune responses and inflammatory reactions. Periodontal pathogens trigger aberrant inflammatory reactions within periodontal tissues, thereby exacerbating the progression of periodontitis. Simultaneously, these pathogens and metabolites stimulate osteoclast differentiation, which leads to alveolar bone resorption. Moreover, a range of systemic diseases, including diabetes, postmenopausal osteoporosis, obesity and inflammatory bowel disease, can contribute to the development and progression of periodontitis. Many studies have underscored the pivotal role of gut microbiota in bone health through the gut-alveolar bone axis. The circulation may facilitate the transfer of gut pathogens or metabolites to distant alveolar bone, which in turn regulates bone homeostasis. Additionally, gut pathogens can elicit gut immune responses and direct immune cells to remote organs, potentially exacerbating periodontitis. This review summarizes the influence of oral microbiota on the development of periodontitis as well as the association between gut microbiota and periodontitis. By uncovering potential mechanisms of the gut-bone axis, this analysis provides novel insights for the targeted treatment of pathogenic bacteria in periodontitis.

The effect of the Litcubanine A on the treatment of murine experimental periodontitis by inhibiting monocyte-macrophage chemotaxis and osteoclast differentiation.

BACKGROUND: Periodontal disease is an inflammatory disease of periodontal tissues that is closely connected with systemic diseases. During periodontitis, the inappropriate recruitment and activation of monocytes-macrophages causes an increase in osteoclast activity and disrupts bone homeostasis. Therefore, it is a promising therapeutic strategy to treat periodontitis by regulating the functions of monocytes-macrophages. Litcubanine A (LA) is an isoquinoline alkaloid extracted from the traditional Chinese medicine Litsea cubeba, which was proven to have reproducible anti-inflammatory effects, but its regulatory role on bone homeostasis in periodontitis is still not clear. METHODS: In this study, zebrafish experiments and a mouse ligature-induced periodontitis model were performed, and histological analysis was used to investigate the effect of LA on macrophage chemotaxis under the inflammatory environment. Real-time PCR was used to detect the regulatory effect of LA (100 nM ~ 100 µM) on the chemotaxis function of macrophages induced by LPS. Apoptosis assay and flow cytometry were used to elucidate the influence of LA on macrophage apoptosis and proliferation. To further clarify the regulatory role of LA on macrophage osteoclast differentiation, real-time PCR, histological analysis, western blot, and micro-computed tomography (micro-CT) were performed in vivo and in vitro to verify the impact of LA on bone homeostasis. RESULTS: Compared with the control group, the chemotaxis function of macrophage was significantly attenuated by LA in vivo. LA could significantly inhibit the expression of genes encoding the chemokine receptors Ccr1 and Cxcr4, and its ligand chemokine Cxcl12 in macrophages, and suppresses the differentiation of osteoclastic precursors to osteoclasts through the MAPK signaling pathway. There were significantly lower osteoclast differentiation and bone loss in the LA group compared with the control in the ligature-induced periodontitis model. CONCLUSION: LA is a promising candidate for the treatment of periodontitis through its reproducible functions of inhibiting monocyte-macrophage chemotaxis and osteoclast differentiation.

The changes and potential effects of zinc homeostasis in periodontitis microenvironment.

Zinc is a very important and ubiquitous element, which is present in oral environment, daily diet, oral health products, dental restorative materials, and so on. However, there is a lack of attention to the role of both extracellular or intracellular zinc in the progression of periodontitis and periodontal regeneration. This review summarizes the characteristics of immunological microenvironment and host cells function in several key stages of periodontitis progression, and explores the regulatory effect of zinc during this process. We find multiple evidence indicate that zinc may be involved and play a key role in the stages of immune defense, inflammatory response and bone remodeling. Zinc supplementation in an appropriate dose range or regulation of zinc transport proteins can promote periodontal regeneration by either enhancing immune defense or up-regulating local cells proliferation and differentiation functions. Therefore, zinc homeostasis is essential in periodontal remodeling and regeneration. More attention is suggested to be focused on zinc homeostasis regulation and consider it as a potential strategy in the studies on periodontitis treatment, periodontal-guided tissue regeneration, implant material transformation, and so on.

Antimicrobial peptides in treatment of Stage III Grade B periodontitis: A randomized clinical trial.

BACKGROUND: To evaluate the effects of antimicrobial peptides (AMPs) on Stage III Grade B periodontitis. METHODS: This trial abided by the principle of consistency test, approved by ethics committee and registered in clinical trials. All qualified 51 patients with Stage III Grade B periodontitis were randomly divided into three groups: SRP group, SRP with minocycline hydrochloride (Mino group) as Control groups, and SRP with AMPs (AMP group) as the Test group. Clinical examinations and subgingival plaques were monitored at baseline and at 7 and 90 days after treatment in the SRP, SRP with AMP and Mino groups. RESULTS: The AMP group (Test group) had a reduced PD (Periodontal probing depth) and an attachment gain significantly higher than SRP and Mino groups (Control groups) at day 90. The abundance of periodontal pathogens was decreased in the AMP group at 7 and 90 days compared with the SRP group and Mino group. Only the AMP group showed an increase the abundance of periodontal probiotics including Capnocytophaga, Gemella, and Lactobacillus at 7 and 90 days. CONCLUSIONS: This study shows that AMPs as an adjunct to SRP promote additional clinical and microbiological benefits in the treatment of Stage III Grade B periodontitis.

The bidirectional effect of neutrophils on periodontitis model in mice: A systematic review.

OBJECTIVE: To evaluate the regulatory role of neutrophils as the first line of host immune defense in the periodontal microenvironment of mice. METHODS: A systematic search was performed using PubMed, Web of Science, and ScienceDirect databases for articles published between 2012 and 2023. In this review, articles investigating the effect of neutrophils on alveolar bone resorption in a mouse model of periodontitis were selected and evaluated according to eligibility criteria. Important variables that may influence outcomes were analyzed. RESULTS: Eleven articles were included in this systematic review. The results showed that because of their immune defense functions, the functional homeostasis of local neutrophils is critical for periodontal health. Neutrophil deficiency aggravates alveolar bone loss. However, several studies have shown that excessive neutrophil infiltration is positively correlated with alveolar bone resorption caused by periodontitis in mice. Therefore, the homeostasis of neutrophil function needs to be considered in the treatment of periodontitis. CONCLUSIONS: Pooled analysis suggests that neutrophils play a bidirectional role in periodontal tissue remodeling in mouse periodontitis models. Therefore, targeted regulation of local neutrophil function provides a novel strategy for the treatment of periodontitis.

Macrophage-derived apoptotic bodies impair the osteogenic ability of osteoblasts in periodontitis.

OBJECTIVES: Periodontitis is induced by the imbalance between osteoblast and osteoclast activity, which leads to periodontal tissue destruction. Macrophages play a vital role in periodontitis. However, the hypoxic periodontal environment will also induce macrophage apoptosis within a short time. Apoptotic bodies (ABs) are the major products generated from apoptotic cells, but whether macrophage-derived ABs play a regulatory role as their mother cells in periodontitis remains unknown. In the present study, we aimed to investigate the effects of ABs on osteoblasts. METHOD: ABs derived from hypoxia-induced macrophages were co-cultured with osteoblasts and the impact of ABs on osteoblast differentiation in vitro was assessed. In vivo, periodontitis model was established and macrophages-derived ABs were injected into the gingival sulcus. The effects of ABs on periodontal bone resorption were determined. RESULTS: The results showed that ABs significantly inhibit osteoblast differentiation and promoted alveolar bone resorption in periodontitis. MicroRNA (miRNAs) array analysis was performed and revealed that miR-483-5p is the key miRNA in ABs. Dual luciferase reporter assays were performed and confirmed that miR-483-5p targeted Col1A1 mRNA and attenuated its expression. CONCLUSION: Macrophage-derived ABs inhibit osteoblast differentiation via the transfer of miR-483-5p, which downregulates Col1A1 expression and finally suppresses osteogenic activity.

Lactobacillus rhamnosus inhibits osteoclast differentiation by suppressing the TLR2/NF-κB pathway.

OBJECTIVE: This study aimed to investigate the role of ultrasonicated Lactobacillus rhamnosus extract in osteoclast differentiation and its underlying mechanism, providing new strategies for the treatment of periodontitis. MATERIALS AND METHODS: Osteoclasts were induced using macrophage colony-stimulating factor and receptor activator for nuclear factor-κB ligand. Lactobacillus rhamnosus extracts were obtained via ultrasonic crushing and ultracentrifugation. The effects of the LGG extract on osteoclast differentiation were evaluated, and the related signaling pathways were examined using western blotting. A mouse periodontitis model was established, and Lactobacillus rhamnosus extract was injected into the gingival sulcus to evaluate the inhibitory effect of Lactobacillus rhamnosus extract on alveolar bone resorption. RESULTS: At 50 µg/mL, Lactobacillus rhamnosus extract inhibited osteoclast differentiation with no effect on apoptosis and proliferation. This phenomenon was achieved by deactivating the NF-κB/c-Fos/NFATc1 signaling pathway through toll-like receptor 2. The in vivo results showed that the local injection of Lactobacillus rhamnosus extract suppressed osteoclast differentiation and alveolar bone resorption. CONCLUSION: The ultrasonicated extract of Lactobacillus rhamnosus inhibited osteoclast differentiation by suppressing the activation of the NF-κB/c-Fos/NFATc1 pathway. Furthermore, it inhibited the destruction of the alveolar bone, providing a new strategy for the use of probiotics in the treatment of periodontitis.

Regulation of the Host Immune Microenvironment in Periodontitis and Periodontal Bone Remodeling.

The periodontal immune microenvironment is a delicate regulatory system that involves a variety of host immune cells including neutrophils, macrophages, T cells, dendritic cells and mesenchymal stem cells. The dysfunction or overactivation of any kind of local cells, and eventually the imbalance of the entire molecular regulatory network, leads to periodontal inflammation and tissue destruction. In this review, the basic characteristics of various host cells in the periodontal immune microenvironment and the regulatory network mechanism of host cells involved in the pathogenesis of periodontitis and periodontal bone remodeling are summarized, with emphasis on the immune regulatory network that regulates the periodontal microenvironment and maintains a dynamic balance. Future strategies for the clinical treatment of periodontitis and periodontal tissue regeneration need to develop new targeted synergistic drugs and/or novel technologies to clarify the regulatory mechanism of the local microenvironment. This review aims to provide clues and a theoretical basis for future research in this field.

Stevioside reduces inflammation in periodontitis by changing the oral bacterial composition and inhibiting P. gingivalis in mice.

BACKGROUND: Excessive sugar intake has become a major challenge in modern societies. Stevioside is a promising non-calorie sweetener with anti-inflammatory effects; however, its effects on the oral environment and periodontitis remain unclear. Therefore, this study explores the effect of stevioside on periodontitis in mice. METHODS: Mice were divided into four groups, namely, control, treated with water, and periodontitis models, established using 5 - 0 silk sutures ligation around the second molar then infected the oral cavity with Porphyromonas gingivalis (P. gingivalis) viscous suspension, divided into three groups treated with 0.1% stevioside (P + S), 10% glucose (P + G), or water (P). Micro-CT scanning was used to assess alveolar bone resorption, while RT-PCR was used to evaluate the inflammatory factors expression and P. gingivalis invasion in the gingiva. The composition of the oral bacteria was analysed using 16 S rRNA sequence in the saliva. In addition, P. gingivalis was co-cultured with stevioside at different concentrations in vitro, and bacterial activity was detected via optical density values and live/dead staining. The virulence was detected using RT-PCR, while biofilm formation was detected using scanning electron microscopy. RESULTS: Compared with 10% glucose, treatment with 0.1% stevioside reduced alveolar bone absorption and osteoclasts while decreasing IL-6, TNF-α, IL-1ß, and P. gingivalis in the gingiva of periodontitis mice. The CEJ-ABC distance in the P + S group was significantly lower than that in the P and P + G groups (P < 0.05). Moreover, the composition of the oral bacteria in the P + S group was similar to that of the control. In vitro stevioside treatment also reduced the bacterial activity and toxicity of P. gingivalis in a dose-dependent manner and affected its biofilm composition. CONCLUSION: Our results indicate that, compared with 10% glucose, 0.1% stevioside intake can reduce alveolar bone resorption and inflammation in periodontal tissues in mice; the bacterial composition following 0.1% stevioside intake was similar to that of a healthy environment. In vitro, high concentrations of stevioside reduced P. gingivalis activity, biofilm formation, and virulence expression. Therefore, stevioside is a potential alternative to glucose for patients with periodontitis.

MicroRNA-155 targets SOCS1 to inhibit osteoclast differentiation during orthodontic tooth movement.

BACKGROUND: MicroRNA-155 (miR-155) is a multifunctional miRNA whose expression is known to be involved in a range of physiological and pathological processes. Its association with several oral diseases has been established. However, the specific role of miR-155 in orthodontic tooth movement remains unclear. In this study, we investigated the impact of miR-155 on osteoclast differentiation and orthodontic tooth movement models, aiming to explore the underlying mechanisms. METHODS: In this experiment, we utilized various agents including miR-155 mimic, miR-155 inhibitor, as well as non-specific sequences (NC mimic & NC inhibitor) to treat murine BMMNCs. Subsequently, osteoclast induction (OC) was carried out to examine the changes in the differentiation ability of monocytes under different conditions. To assess these changes, we employed RT-PCR, Western blotting, and TRAP staining techniques. For the orthodontic tooth movement model in mice, the subjects were divided into two groups: the NaCl group (injected with saline solution) and the miR-155 inhibitor group (injected with AntagomiR-155). We observed the impact of orthodontic tooth movement using stereoscopic microscopy, micro-CT, and HE staining. Furthermore, we performed RT-PCR and Western blotting analyses on the tissues surrounding the moving teeth. Additionally, we employed TargetScan to predict potential target genes of miR-155. RESULTS: During osteoclast induction of BMMNCs, the expression of miR-155 exhibited an inverse correlation with osteoclast-related markers. Overexpression of miR-155 led to a decrease in osteoclast-related indexes, whereas underexpression of miR-155 increased those indexes. In the mouse orthodontic tooth movement model, the rate of tooth movement was enhanced following injection of the miR-155 inhibitor, leading to heightened osteoclast activity. TargetScan analysis identified SOCS1 as a target gene of miR-155. CONCLUSIONS: Our results suggest that miR-155 functions as an inhibitor of osteoclast differentiation, and it appears to regulate osteoclasts during orthodontic tooth movement. The regulatory mechanism of miR-155 in this process involves the targeting of SOCS1.

DNA methylation alterations and their potential influence on macrophage in periodontitis.

OBJECTIVES: To explore how various methylation mechanisms function and affect macrophages in periodontitis, with an aim of getting a comprehensive understanding of pathogenesis of the disease. SUBJECT: Alterations in DNA methylation are associated with different periodontitis susceptible factors and disrupt immunity homeostasis. The host's immune response to stimulus plays a vital role in the progression of periodontitis. Macrophages are key immune cells of immune system. They act as critical regulators in maintaining issue homeostasis with their nature of high plasticity. The altered methylation status of genes may cause abnormal expression of proteins in the progress of periodontitis, thus, exert potential influence on macrophages. RESULTS: Certain genes are selectively activated or silenced due to the changes in the methylation status, which causes the alteration of the expression level of cytokines/chemokines, signal molecules, extracellular matrix molecules, leads to the change in local microenvironment, affects activation states of immune cells including macrophages, thus influences the host immune response during periodontitis.. This results in differential susceptibility and therapeutic outcome. CONCLUSION: DNA methylation alteration may cause aberrant expression level of genes associated with periodontal diseases, thus results in deregulation of macrophages, which supports the prospect of using DNA methylation-related parameter as a new biomarker for the diagnosis and treatment of periodontitis.

Advances in the Therapeutic Effects of Apoptotic Bodies on Systemic Diseases.

Apoptosis plays an important role in development and in the maintenance of homeostasis. Apoptotic bodies (ApoBDs) are specifically generated from apoptotic cells and can contain a large variety of biological molecules, which are of great significance in intercellular communications and the regulation of phagocytes. Emerging evidence in recent years has shown that ApoBDs are essential for maintaining homeostasis, including systemic bone density and immune regulation as well as tissue regeneration. Moreover, studies have revealed the therapeutic effects of ApoBDs on systemic diseases, including cancer, atherosclerosis, diabetes, hepatic fibrosis, and wound healing, which can be used to treat potential targets. This review summarizes current research on the generation, application, and reconstruction of ApoBDs regarding their functions in cellular regulation and on systemic diseases, providing strong evidence and therapeutic strategies for further insights into related diseases.

Sodium butyrate inhibits osteogenesis in human periodontal ligament stem cells by suppressing smad1 expression.

BACKGROUND: Butyrate is a major subgingival microbial metabolite that is closely related to periodontal disease. It affects the proliferation and differentiation of mesenchymal stem cells. However, the mechanisms by which butyrate affects the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) remain unclear. Here, we investigated the effect of sodium butyrate (NaB) on the osteogenic differentiation of human PDLSCs. METHODS: PDLSCs were isolated from human periodontal ligaments and treated with various concentrations of NaB in vitro. The cell counting kit-8 assay and flow cytometric analysis were used to assess cell viability. The osteogenic differentiation capabilities of PDLSCs were evaluated using the alkaline phosphatase activity assay, alizarin red staining, RT-PCR, western blotting and in vivo transplantation. RESULTS: NaB decreased PDLSC proliferation and induced apoptosis in a dose- and time-depend manner. Additionally, 1 mM NaB reduced alkaline phosphatase activity, mineralization ability, and the expression of osteogenic differentiation-related genes and proteins. Treatment with a free fatty acids receptor 2 (FFAR2) antagonist and agonist indicated that NaB inhibited the osteogenic differentiation capacity of PDLSCs by affecting the expression of Smad1. CONCLUSION: Our findings suggest that NaB inhibits the osteogenic differentiation of PDLSCs by activating FFAR2 and decreasing the expression of Smad1.

Regeneration characteristics of different dental derived stem cell sheets.

BACKGROUND: Although cell sheets have gained much interest as a non-scaffold strategy for tissue regeneration, the regenerative features of different cell sheets remain unclear. OBJECTIVE: In this study, we aimed to compare the regeneration characteristics of cell sheets derived from dental pulp stem cells (DPSCs), periodontal ligament stem cells (PDLSCs) and stem cells of the apical papilla (SCAPs). METHODS: Dental pulp stem cells, PDLSCs and SCAPs from the same individual were acquired and induced to form sheets using 20 µg/mL vitamin C. Immunofluorescence staining was used to detect the expression of collagen I, fibronectin, integrin ß1 and vimentin. Real-time PCR was used to determine NANOG, OCT4, SOX2 and TERT gene expression. The cell sheets with hydroxyapatite/tricalcium phosphate were transplanted into nude mice subcutaneously to evaluate tissue regeneration characteristics. RESULTS: No obvious differences were found in the histological structure and extracellular matrix protein expression between DPSC, PDLSC and SCAP sheets. Dental pulp stem cell sheet showed higher expression of OCT4 and TERT than PDLSC and SCAP sheets. All three cell sheets displayed the ability of mineral tissue formation and highly expressed periostin. The tissue derived from DPSC sheet showed higher CD31 expression and porous fibres compared with that from the others. The tissue fibres formed from PDLSC sheet were directionally arranged, while the tissue derived from SCAP sheet showed highest mineral tissue formation. CONCLUSION: Although in vitro DPSC, PDLSC and SCAP cell sheets have similar characteristics, their regenerative characteristics in vivo are different, with each showing potential application for regeneration of different tissues.