LncKCNQ1OT1 Promotes the Odontoblastic Differentiation of Dental Pulp Stem Cells via Regulating hsa-miR-153-3p/RUNX2 Axis.

This study aimed to explore the role of LncKCNQ1OT1/hsa-miR-153-3p/RUNX2 in the odontoblastic differentiation of human dental pulp stem cells (DPSCs) and its possible mechanism. The expression of LncKCNQ1OT1, hsa-miR-153-3p, and RUNX2 in the odontoblastic differentiation was detected by qRT-PCR. Interaction between LncKCNQ1OT1 and hsa-miR-153-3p and interaction between hsa-miR-153-3p and RUNX2 were detected by dual-luciferase assay. The cell viability of DPSCs was detected by CCK-8, and the effect of LncKCNQ1OT1 and hsa-miR-153-3p on the odontoblastic differentiation of DPSCs was observed by alizarin red staining, alkaline phosphatase (ALP) activity assay, and Western blot for RUNX2, DSPP, and DMP-1. The results showed, during odontoblastic differentiation of DPSCs, the expression of LncKCNQ1OT1 increased, hsa-miR-153-3p expression decreased, and RUNX2 expression increased. Dual-luciferase assay showed that LncKCNQ1OT1 sponges hsa-miR-153-3p and hsa-miR-153-3p targets on RUNX2. After LncKCNQ1OT1 and hsa-miR-153-3p expressions of DPSCs were changed, the cell viability was not notably changed, but the odontoblastic differentiation was notably changed, which was confirmed with Alizarin Red staining, ALP activity, and Western blot for RUNX2, DSPP, and DMP-1. The results indicate that LncKCNQ1OT1 promotes the odontoblastic differentiation of DPSCs via regulating hsa-miR-153-3p/RUNX2 axis, which may provide a therapeutic clue for odontogenesis.

General Control Nonrepressed Protein 5 Modulates Odontogenic Differentiation Through NF-κB Pathway in Tumor Necrosis Factor-α-Mediated Impaired Human Dental Pulp Stem Cells.

Dental pulp stem cells (DPSCs) from pulpitis patients showed defective osteogenic differentiation. However, as the most well-studied histone acetyltransferase, the impaired general control nonrepressed protein 5 (GCN5) plays essential roles in various developmental processes. The aim of this study was to investigate the effect of GCN5 on DPSCs odontogenic differentiation. The healthy dental pulp tissues were obtained from the extracted impacted third molar of patients with the informed consent. DPSCs were treated with a high concentration of tumor necrosis factor-alpha (TNF-α) (100 ng/mL) and odontogenic differentiation-related gene and GCN5 protein level by Western blot analysis. Proliferation of the DPSCs was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Immunofluorescence staining detected GCN5 and NF-κB signaling for p-p65. The mechanism of GCN5 regulating odontogenic differentiation of DPSCs was determined by small interfering RNA analysis. Our data suggested that TNF-α can significantly reduce mineralization and the expression of dentin matrix acidic phosphoprotein 1 and dentin sialophosphoprotein at higher concentration (100 ng/mL). Meanwhile, it showed that the inflammation in microenvironment resulted in a downregulation of GCN5 expression and GCN5 knockdown caused decreased odontogenic differentiation of DPSCs was also found. In addition, the knockdown of GCN5 increased the expression of phosphorylation of p65, thus activating NF-κB pathway of DPSCs. Meanwhile, NF-κB pathway inhibitor pyrrolidinedithiocarbamic acid reversed the siGCN5 decreased odontogenic differentiation of DPSCs. Altogether, our findings indicated that in inflammatory microenvironments GCN5 plays a protective role in pulpitis impaired odontogenic differentiation of DPSCs by activating NF-κB pathway, which may provide a potential approach to dentin regeneration.

Basic fibroblast growth factor promotes human dental pulp stem cells cultured in 3D porous chitosan scaffolds to neural differentiation.

AIM/PURPOSE: Dental pulp stem cells (DPSCs) were widely used as seed cells in the field of tissue engineering and regenerative medicine, including spinal cord injury (SCI) repair and other neuronal degenerative diseases, due to their easy isolation, multiple differentiation potential, low immunogenicity and low rates of rejection during transplantation. Various studies have shown that bFGF can enhance peripheral nerve regeneration after injury, and phospho-ERK (p-ERK) activation as a major mediator may be involved in this process. Previous studies also have proved that a suitable biomaterial scaffold can carry and transport the therapeutic cells effectively to the recipient area. It has showed in our earlier experiments that 3D porous chitosan scaffolds exhibited a suitable circumstance for survival and neural differentiation of DPSCs in vitro. The purpose of the study was to evaluate the influence of chitosan scaffolds and bFGF on differentiation of DPSCs. MATERIALS AND METHODS: In current study, DPSCs were cultured in chitosan scaffolds and treated with neural differentiation medium for 7 days. The neural genes and protein markers were analyzed by western blot and immunofluorescence. Meanwhile, the relevant signaling pathway involved in this process was also tested. RESULTS: Our study revealed that the viability of DPSCs was not influenced by co-culture with the chitosan scaffolds as well as bFGF. Compared with the control and DPSC/chitosan-scaffold groups, the levels of GFAP, S100ß and ß-tubulin III significantly increased in the DPSC/chitosan-scaffold+bFGF group. CONCLUSION: Chitosan scaffolds were non-cytotoxic to the survival of DPSCs, and chitosan scaffolds combined with bFGF facilitated the neural differentiation of DPSCs. The transplantation of DPSCs/chitosan-scaffold+bFGF might be a secure and effective method of treating SCI and other neuronal diseases.

RICK regulates the odontogenic differentiation of dental pulp stem cells through activation of TNF-α via the ERK and not through NF-κB signaling pathway.

Dental pulp stem cells (DPSCs) are capable of both self-renewal and multilineage differentiation, which play a positive role in dentinogenesis. Studies have shown that tumor necrosis factor-α (TNF-α) is involved in the differentiation of DPSCs under pro-inflammatory stimuli, but the mechanism of action of TNF-α is unknown. Rip-like interacting caspase-like apoptosis-regulatory protein kinase (RICK) is a biomarker of an early inflammatory response that plays a key role in modulating cell differentiation, but the role of RICK in DPSCs is still unclear. In this study, we identified that RICK regulates TNF-α-mediated odontogenic differentiation of DPSCs via the ERK signaling pathway. The expression of the biomarkers of odontogenic differentiation dental matrix protein-1 (DMP-1), dentin sialophosphoprotein (DSPP), biomarkers of odontogenic differentiation, increased in low concentration (1-10 ng/ml) of TNF-α and decreased in high concentration (50-100 ng/ml). Odontogenic differentiation increased over time in the odontogenic differentiation medium. In the presence of 10 ng/L TNF-α, the expression of RICK increased gradually over time, along with odontogenic differentiation. Genetic silencing of RICK expression reduced the expression of odontogenic markers DMP-1 and DSPP. The ERK, but not the NF-κB signaling pathway, was activated during the odontogenic differentiation of DPSCs. ERK signaling modulators decreased when RICK expression was inhibited. PD98059, an ERK inhibitor, blocked the odontogenic differentiation of DPSCs induced by TNF-α. These results provide a further theoretical and experimental basis for the potential use of RICK in targeted therapy for dentin regeneration.

Effectiveness of low-intensity pulsed ultrasound on osteoarthritis of the temporomandibular joint: A review.

Loading is indispensable for the growth, development, and maintenance of joint tissues, including mandibular condylar cartilage, but excessive loading or reduced host adaptive capacity can considerably damage the temporomandibular joint (TMJ), leading to temporomandibular joint osteoarthritis (TMJ-OA). TMJ-OA, associated with other pathological conditions and aging processes, is a highly degenerative disease affecting the articular cartilage. Many treatment modalities for TMJ-OA have been developed. Traditional clinical treatment includes mainly nonsurgical options, such as occlusal splints. However, non-invasive therapy does not achieve joint tissue repair and regeneration. Growing evidence suggests that low-intensity pulsed ultrasound (LIPUS) accelerates bone fracture healing and regeneration, as well as having extraordinary effects in terms of soft tissue repair and regeneration. The latter have received much attention, and various studies have been performed to evaluate the potential role of LIPUS in tissue regeneration including that applied to articular cartilage. The present article provides an overview of the status of LIPUS stimulation used to prevent the onset and progression of TMJ-OA and enhance the tissue regeneration of mandibular condylar cartilage. The etiology and management of TMJ-OA are explained briefly, animal models of TMJ-OA are described, and the effectiveness of LIPUS on cell metabolism and tissue regeneration in the TMJ is discussed.

Comparison of immunomodulatory properties of exosomes derived from bone marrow mesenchymal stem cells and dental pulp stem cells.

Substantial discoveries suggested that exosomes released from multiple sources of stem cells can affect the biological functions of target cells. In present period, the immunosuppressive properties of exosomes derived from bone marrow mesenchymal stem cells (BMMSCs-E) have been extensively recognized, but few studies have been reported about exosomes secreted from dental pulp stem cells (DPSCs-E) in the field of medical immunity. Hence, the aim of this study is to compare the immunomodulatory capacity of BMMSCs-E and DPSCs-E. Peripheral blood mononuclear cells (PBMCs) were co-cultured with them respectively and the proportion of regulatory T cells (Treg) was detected to increase. Subsequently, we stimulated CD4+T cells with BMMSCs-E and DPSCs-E to observe their effects on the polarizations, chemokines secretion, apoptosis, and proliferation of CD4+T cells. We found that DPSCs-E inhibited the differentiation of CD4+T cells into T helper 17 cells (Th17) and reduced the secretions of pro-inflammatory factors IL-17 and TNF-α, while promoted the polarization of CD4+T cells into Treg and increased the release of anti-inflammatory factors IL-10 and TGF-ß. What's more, these capabilities of DPSCs-E were stronger than those of BMMSCs-E. In addition, DPSCs-E were more effective in inducing apoptosis of CD4+T cells compared with BMMSCs-E, and DPSCs-E inhibited the proliferation of CD4+T cells, which is similar to BMMSCs-E. We draw a conclusion that DPSCs-E have stronger immune-modulating activities than BMMSCs-E, and may be a new therapeutic tool for the treatment of immunological diseases.

miR-140-5p regulates the odontoblastic differentiation of dental pulp stem cells via the Wnt1/ß-catenin signaling pathway.

BACKGROUND: MicroRNAs (miRNAs) play a key role in regulating cell differentiation. In the present study, we aimed to explore the role of miR-140-5p in odontoblastic differentiation of dental pulp stem cells (DPSCs). METHODS: DPSCs from normal human impacted third molars were isolated and cultured. After overexpression or silencing of miR-140-5p in DPSCs, activity, proliferation, and odontoblastic differentiation of DPSCs were evaluated. The possible target gene of miR-140-5p was verified by luciferase reporter gene assay. Using gene transfection technology, RT-CPR, and Western blot to confirm miR-140-5p regulates the odontoblastic differentiation of DPSCs through Wnt1/ß-catenin signaling. RESULTS: We found the expression of miR-140-5p decreased in the differentiated DPSCs for odontoblastic cells, and at the same time, the expressions of Wnt1 and ß-catenin increased. Wnt1 was the target gene of miR-140-5p which was confirmed by luciferase reporter gene system. miR-140-5p overexpression suppressed the expression of Wnt1. miR-140-5p inhibitor could promote the odontoblastic differentiation of DPSCs. miR-140-5p mimic could weaken the odontoblastic differentiation of DPSCs, which could be reversed by the overexpression of Wnt1. CONCLUSION: Our data demonstrated that miR-140-5p regulates the odontoblastic differentiation of DPSCs via targeting Wnt1/ß-catenin signaling. Therefore, miR-140-5p might be a molecular target to regulate the odontoblastic differentiation for the therapeutic agents in dental medicine.

Rosuvastatin Regulates Odontoblast Differentiation by Suppressing NF-κB Activation in an Inflammatory Environment.

Rosuvastatin is a synthetic statin of 3-hydroxy-methyl-3-glutamyl coenzyme A reductase inhibitor. It has pleiotropic characteristics including hepatic selectivity, minimal metabolism, inhibition of inflammation, and induction of osteoblast differentiation. In this study, dental pulp stem cells (DPSCs) were treated with lipopolysaccharide alone or with rosuvastatin. Then, we examined the accelerative effects of rosuvastatin on odontoblast differentiation and mineralized nodule formation by real-time polymerase chain reaction (RT-PCR), western blot, alizarin red S staining, and alkaline phosphatase staining. The extent of anti-inflammation was determined by RT-PCR and analysis of the expression of tumor necrosis factor α, interleukin 1ß (IL-1ß), and IL-6. Furthermore, the activation of nuclear factor kappa B (NF-κB) was determined by western blot. This study demonstrates that rosuvastatin may speed up odontoblast differentiation and rescue inflammatory reaction by suppressing the NF-κB signaling pathway. It is believed that our findings provide novel perceptions on odontogenic differentiation of DPSCs.

CKIP-1 suppresses odontoblastic differentiation of dental pulp stem cells via BMP2 pathway and can interact with NRP1.

AIM: Casein kinase 2 interacting protein-1 (CKIP-1) is a recently discovered intracellular regulator of bone formation, muscle cell differentiation, and tumor cell proliferation. Our study aims to identify the inhibition of BMP2-Smad1/5 signaling by CKIP-1 in odontoblastic differentiation of human dental pulp stem cells (DPSCs). MATERIALS AND METHODS: DPSCs infected CKIP-1 siRNA or transfected CKIP-1 full-length plasmid were cultured in odontoblastic differentiation medium or added noggin (200 ng/mL) for 21 days. We examined the effects of CKIP-1 on odontoblastic differentiation, mineralized nodules formation, and interaction by western blot, real-time polymerase chain reaction (RT-PCR), alkaline phosphatase (ALP) staining, alizarin red S staining, and immunoprecipitation. RESULTS: Firstly, we have demonstrated that CKIP-1 expression markedly decreased time-dependently along with cell odontoblastic differentiation. Indeed, the silence of CKIP-1 upregulated odontoblastic differentiation via BMP2-Smad1/5 signaling, while CKIP-1 over-expression had a negative effect on odontoblastic differentiation of DPSCs. Furthermore, CKIP-1 could interact with Neuropilin-1 (NRP1). CONCLUSIONS: This work provides data that advocates a novel perception on odontoblastic differentiation of DPSCs. Therefore, inhibiting the expression of CKIP-1 may be of great significance to the development of dental caries.

Wedelolactone Enhances Odontoblast Differentiation by Promoting Wnt/ß-Catenin Signaling Pathway and Suppressing NF-κB Signaling Pathway.

Wedelolactone is a multitarget natural plant compound with many pharmacological activities, including anti-inflammatory, anticancer, and antiosteoporosis. In this study, dental pulp stem cells (DPSCs) were treated with or without wedelolactone. We found that wedelolactone stimulated odontoblast differentiation and mineralization. At the molecular level, wedelolactone directly promoted the nuclear accumulation of ß-catenin, and thereafter stimulated the expression of odontoblast-related marker genes containing dentin matrix protein-1 (DMP1), dentin sialophosphoprotein (DSPP), and runt-related transcription factor 2 (Runx2). Furthermore, wedelolactone upregulated the expression of IκBα and inhibited phosphonation and nuclear migration of p65. As a result, wedelolactone remarkably induced odontoblast differentiation through semaphorin 3A (Sema3A)/neuropilin-1 (NRP1) pathway-mediated ß-catenin activation and nuclear factor kappa B (NF-κB) pathway inhibition. Our findings provide novel perceptions on odontogenic differentiation of DPSCs.

MiR-21/STAT3 Signal Is Involved in Odontoblast Differentiation of Human Dental Pulp Stem Cells Mediated by TNF-α.

Dental pulp stem cells (DPSCs), as one type of mesenchymal stem cells (MSCs), have the capability of self-renewal and multipotency to differentiate into several cell lineages, including osteogenesis, odontoblasts, chondrogenesis, neurogenesis, and adipogenesis. It has found that tumor necrosis factor-α (TNF-α) can promote osteogenic differentiation of human DPSCs in our previous studies. Other experimentation revealed that signal transducer and activator of transcription 3 (STAT3) underwent a rapid activation both in osteogenesis and inflammation microenvironment of MSCs in vitro. MicroRNAs (miRNAs or miRs) have been proved in previous studies to regulate MSCs differentiation in vitro. In this study, we identified miR-21 as a key miRNA contributed the functional axis of odontoblast differentiation induced by STAT3. It is observed that the expression of miR-21 and STAT3 increased gradually in low concentration (1-10 ng/mL) of TNF-α, while they were suppressed in high concentration (50-100 ng/mL). The upregulation of miR-21 may facilitate the odontoblast differentiation of DPSCs coordinating with STAT3. SiSTAT3 or treated by the inhibitor of STAT3, cucurbitacin I (Cuc I), significantly increased primary miR-21 expression along with decreased mature miR-21 expression. Meanwhile, the inhibition of miR-21 (anti-miR-21) decreased the activation of STAT3 as well as suppressed the marker proteins of odontoblast differentiation. The results revealed a new function of miR-21, suggesting that miR-21/STAT3 signal may act as a modulator within a complex network of factors to regulate odontoblast differentiation of human DPSCs. It may provide a novel therapeutic strategy to regulate the odontoblast differentiation of DPSCs.

The Role of Neuropilin-1-FYN Interaction in Odontoblast Differentiation of Dental Pulp Stem Cells.

Abnormal odontoblast differentiation of dental pulp stem cells (DPSCs) caused by inflammation is closely related to the development of dental caries. Neuropilin-1 (NRP1) is one of the members of neuropilin family. It can combine with disparate ligands involved in regulating cell differentiation. FYN belongs to the protein-tyrosine kinase family, which has been implicated in the control of cell growth, and the effect can be further strengthened by inflammatory factors. In our studies, we verified that NRP1 can form complexes with FYN and have the correlation changes in odontoblast differentiation of DPSCs. Therefore, we surmise that in the progress of dental caries, NRP1 interacts with FYN, by expanding inflammation and inhibition of odontoblast differentiation of DPSCs through nuclear factor kappa B (NF-κB) signaling pathway. In this subject, we first investigated the expression and interaction of NRP1 and FYN in DPSCs. And then, we researched the effect of this complex controlling downstream signal pathway in normal or inflammation stimulated DPSCs. Finally, we analyzed the relationship between this role and odontoblast differentiation of DPSCs. This research will provide the molecular mechanism of inflammation factors of dental caries through activating NF-κB signal regulating odontoblast differentiation in DPSCs for finding new potential drug targets for the clinical treatment of dental caries.

Clinical Significance and Prognostic Value of the Expression of LAMP3 in Oral Squamous Cell Carcinoma.

Recent studies demonstrated high expression of lysosome-associated membrane protein 3 (LAMP3) in a variety of malignancies including esophageal squamous cell carcinoma, gastrointestinal cancer, breast cancer, and cervical cancer and its involvement in several biological activities of tumor cells. However, the expression of LAMP3 and its value in oral squamous cell carcinoma (OSCC) remain unclear. In this study, we examined the expression of LAMP3 in OSCC tissue samples and investigated the relationship between LAMP3 and clinical characteristics of patients with OSCC. We examined mRNA and protein levels of LAMP3 in OSCC tissues and neighboring normal tissues using quantitative real-time polymerase chain reaction and immunohistochemistry analyses, respectively. Both the mRNA and protein levels of LAMP3 were significantly higher in OSCC tissues than in adjacent normal tissues. Chi-square analysis showed that the high LAMP3 expression was notably linked to the degree of tumor differentiation and advanced TNM stage. Univariate and multivariate analyses showed that the high LAMP3 expression was an independent prognostic marker in OSCC. Our results suggest that LAMP3 might act as a potential anticancer target and a prognostic marker in patients with OSCC.

SIRT1 was involved in TNF-α-promoted osteogenic differentiation of human DPSCs through Wnt/ß-catenin signal.

Dental pulp stem cells (DPSCs), as one type of mesenchymal stem cells (MSCs), have the capability of self-renewal and differentiating along the various directions, including osteogenic, chondrogenic, neurogenic, and adipogenic. We previously study and found that tumor necrosis factor-α (TNF-α) promoted osteogenic differentiation of human DPSCs via the Wnt/ß-catenin signaling pathway in low concentration while inhibited that in high concentration. In the abovementioned process, we found that sirtuin-1 (SIRT1) had the same change compared with the characteristic protein of bone formation, such as bone morphogenetic protein 2 (BMP2), runt-related transcription factor 2 (Runx2), and collagen I (COL1). We asked whether SIRT1 could regulate osteogenesis of DPSCs. In inflammation microenvironment constructed by TNF-α, we tested the expression changing of SIRT1 and analyzed the function of SIRT1 on osteogenic differentiation of DPSCs. SIRT1 deacetylated ß-catenin, and then promote its accumulation in the nucleus. Accumulated ß-catenin can lead to transcription of osteogenic characteristic genes. Using the activator of SIRT1, resveratrol, could promote the above-mentioned process of osteogenic differentiation. SIRT1 could regulate osteogenesis of DPSCs through Wnt/ß-catenin signal. SIRT1, as a regulator of differentiation of DPSCs, may be a new target for cell-based therapy in oral diseases and other regenerative medicine.

Runx2 modified dental pulp stem cells (DPSCs) enhance new bone formation during rapid distraction osteogenesis (DO).

Distraction osteogenesis (DO) remains a major challenge in orthopedic and craniofacial surgery. The transplantion of mesenchymal stem cells (MSCs) could reduce the treatment period and the associated complications by increasing new bone formation during long-bone DO. Runt-related transcription factor 2 (Runx2) encodes a nuclear protein that is a pivotal regulator of osteoblast differentiation. It significantly stimulates calcium accumulation and alkaline phosphatase (ALP) activity in dental pulp stem cells (DPSCs). In this study, we investigated the effects of gene therapy using Runx2 on new bone formation during tibia DO of rabbits. The distraction gap of the rabbits was injected with adenovirus (Adv)-Runx2-green fluorescent protein (GFP)-transfected DPSCs (overexpression group, Group OE) or Adv-GFP-transfected DPSCs (negative control group, Group NC). Rabbits in the control group (Groups CON) were injected with physiologic saline. The generation of new bone tissue in the distraction gap was studied by radiographic examination, micro-computed tomography (CT) evaluation, histological analyze, and Mechanical testing at weeks 8 in the consolidation period. Excellent bone formation in the distracted callus was observed in Group OE and Group NC. Moreover, the OE group showed better bone formation and the highest bone mineral density (BMD) and bone mineral content (BMC). Group CON animals showed inadequate bone formation in the distracted callus compared to the other groups. The results suggest that gene therapy using Runx2-modified DPSCs was more effective during bone deposition and new bone formation in tibia DO.

LTBP2 is a prognostic marker in head and neck squamous cell carcinoma.

Latent transforming growth factor (TGF)-beta binding protein 2 (LTBP2) belongs to the fibrillin/LTBP extracellular matrix glycoprotein superfamily. It plays vital roles in tumorigenesis through regulating TGFß activity, elastogenesis and maintenance of the extracellular matrix (ECM) structure. In this study, we determined the expression levels of LTBP2 mRNA and protein in head and neck squamous cell carcinoma (HNSCC) tissues and adjacent normal tissues by quantitative reverse transcription PCR (qRT-PCR) and tissue microarray immunohistochemistry analysis (TMA-IHC) respectively. LTBP2 protein levels in cancer tissues were correlated with HNSCC patients' clinical characteristics and overall survival. Both LTBP2 mRNA and protein levels were significantly higher in HNSCC tissues than in adjacent normal tissues. High LTBP2 protein level was associated with lymph node metastasis and higher pTNM stages. High LTBP2 protein level is an independent prognostic marker in HNSCC. Our data suggest that LTBP2 acts as an oncogene in HNSCC development and progression. Detection of LTBP2 expression could be a useful prognosis marker and targeting LTBP2 may represent a novel strategy for cancer treatment through regulating activities of TGFß.

Chitosan scaffolds induce human dental pulp stem cells to neural differentiation: potential roles for spinal cord injury therapy.

Cell-based transplantation strategies hold great potential for spinal cord injury (SCI) repair. Chitosan scaffolds have therapeutic benefits for spinal cord regeneration. Human dental pulp stem cells (DPSCs) are abundant available stem cells with low immunological incompatibility and can be considered for cell replacement therapy. The purpose of this study is to investigate the role of chitosan scaffolds in the neural differentiation of DPSCs in vitro and to assess the supportive effects of chitosan scaffolds in an animal model of SCI. DPSCs were incubated with chitosan scaffolds. Cell viability and the secretion of neurotrophic factors were analyzed. DPSCs incubated with chitosan scaffolds were treated with neural differentiation medium for 14 days and then neural genes and protein markers were analyzed by Western blot and reverse transcription plus the polymerase chain reaction. Our study revealed a higher cell viability and neural differentiation in the DPSC/chitosan-scaffold group. Compared with the control group, the levels of BDNF, GDNF, b-NGF, and NT-3 were significantly increased in the DPSC/chitosan-scaffold group. The Wnt/ß-catenin signaling pathway played a key role in the neural differentiation of DPSCs combined with chitosan scaffolds. Transplantation of DPSCs together with chitosan scaffolds into an SCI rat model resulted in the marked recovery of hind limb locomotor functions. Thus, chitosan scaffolds were non-cytotoxic and provided a conducive and favorable microenvironment for the survival and neural differentiation of DPSCs. Transplantation of DPSCs might therefore be a suitable candidate for treating SCI and other neuronal degenerative diseases.

AGS3 is involved in TNF-α medicated osteogenic differentiation of human dental pulp stem cells.

Dental pulp stem cells (DPSCs) are multipotent adult stem cells capable of differentiating along the osteoblast, adipocyte, and chondrocyte lineages. Regulating differentiation of DPSCs may be a useful tool for regenerative medicine and cell-based therapy in oral diseases. Multisignaling pathways are involved in osteogenic differentiation of DPSCs. Recent studies show that cAMP/PKA/CREB signaling could stimulate the expression of genes such as bone morphogenic proteins 2 (BMP2), inhibitor of DNA binding 2 (ID2), bone sialoprotein, osteocalcin, and type XXIV collagen, which have been implicated in osteogenesis and bone formation. Activator of G-protein signaling 3 (AGS3, gene name G-protein signaling modulator-1, Gpsm1), an accessory protein for G-protein signaling, plays an important role in regulating the phosphorylation of cyclic AMP response element-binding protein (p-CREB). However, the involvement of AGS3 in osteogenic differentiation of DPSCs has not been explored. Our data indicated that increased expression of AGS3 would inhibit osteogenic differentiation of DPSCs exposed to inflammatory cytokine tumor necrosis factor α (TNF-α) via cAMP/PKA/CREB signaling. The negative role of AGS3 in osteogenic differentiation was further confirmed by knocking down and over expression of AGS3. Our findings may provide clinical implications for osteoporosis.

RAC1 regulate tumor necrosis factor-α-mediated impaired osteogenic differentiation of dental pulp stem cells.

Human dental pulp contains a rapidly proliferative subpopulation of precursor cells termed dental pulp stem cells (DPSCs) that show self-renewal and multilineage differentiation, including neurogenic, chondrogenic, osteogenic and adipogenic. We previously reported that tomuor necrosis factor-α (TNF-α) (10 ng/mL) triggered osteogenic differentiation of human DPSCs via the nuclear factor-κB (NF-κB) signaling pathway. While previous studies showed that cells treated with TNF-α at higher concentrations showed decreased osteogenic differentiation capability. In this study we analyze the function of TNF-α (100 ng/mL) on osteogenic differentiation of human DPSCs for the first time and identify the underlying molecule mechanisms. Our data revealed that TNF-α with higher concentration significantly reduced mineralization and the expression of bone morphogenetic protein 2 (BMP2), alkaline phosphatase (ALP) and runt-related transcription factor 2 (RUNX2). Further, we revealed that TNF-α could suppress the osteogenic differentiation of DPSCs via increasing the expression of RAC1, which could activate the Wnt/ß-catenin signaling pathway and liberate ß-catenin to translocate into the nucleus. Genetic silencing of RAC1 expression using siRNA restored osteogenic differentiation of DPSCs. Our findings may provide a potential approach to bone regeneration in inflammatory microenvironments.

p16(INK4A) mediates age-related changes in mesenchymal stem cells derived from human dental pulp through the DNA damage and stress response.

Mesenchymal stem cells derived from human dental pulp (DP-MSCs) are characterized by self-renewal and multi-lineage differentiation, which play important roles in regenerative medicine. Autologous transfers, as non-immunogenic, constitute the safest approach in cellular transplantations. However, their use may be limited by age-related changes. In the study, we compared DP-MSCs isolated from human in five age groups: 5-12 y, 12-20 y, 20-35 y, 35-50 y, and >50 y. We tested the effect of age on proliferation, differentiation, senescence-associated ß-galactosidase (SA-ß-gal), cell cycle and programmed cell death. DP-MSCs showed characteristics of senescence as a function of age. Meanwhile, the expression of p16(INK4A) and γ-H2A.X significantly increased with age, whereas heat shock protein 60 (HSP60) was decreased in the senescent DP-MSCs. Reactive oxygen species (ROS) staining showed the number of ROS-stained cells and the DCFH fluorescent level were higher in the aged group. Further we examined the senescence of DP-MSCs after modulating p16(INK4A) signaling. The results indicated the dysfunction of DP-MSCs was reversed by p16(INK4A) siRNA. In summary, our study indicated p16(INK4A) pathway may play a critical role in DP-MSCs age-related changes and the DNA damage response (DDR) and stress response may be the main mediators of DP-MSCs senescence induced by excessive activation of p16(INK4A) signaling.