Single-cell RNA sequencing analysis of the temporomandibular joint condyle in 3 and 4-month-old human embryos.

BACKGROUND: The temporomandibular joint (TMJ) is a complex joint consisting of the condyle, the temporal articular surface, and the articular disc. Functions such as mastication, swallowing and articulation are accomplished by the movements of the TMJ. To date, the TMJ has been studied more extensively, but the types of TMJ cells, their differentiation, and their interrelationship during growth and development are still unclear and the study of the TMJ is limited. The aim of this study was to establish a molecular cellular atlas of the human embryonic temporomandibular joint condyle (TMJC) by single-cell RNA sequencing, which will contribute to understanding and solving clinical problems. RESULTS: Human embryos at 3 and 4 months of age are an important stage of TMJC development. We performed a comprehensive transcriptome analysis of TMJC tissue from human embryos at 3 and 4 months of age using single-cell RNA sequencing. A total of 16,624 cells were captured and the gene expression profiles of 15 cell clusters in human embryonic TMJC were determined, including 14 known cell types and one previously unknown cell type, "transition state cells (TSCs)". Immunofluorescence assays confirmed that TSCs are not the same cell cluster as mesenchymal stem cells (MSCs). Pseudotime trajectory and RNA velocity analysis revealed that MSCs transformed into TSCs, which further differentiated into osteoblasts, hypertrophic chondrocytes and tenocytes. In addition, chondrocytes (CYTL1high + THBS1high) from secondary cartilage were detected only in 4-month-old human embryonic TMJC. CONCLUSIONS: Our study provides an atlas of differentiation stages of human embryonic TMJC tissue cells, which will contribute to an in-depth understanding of the pathophysiology of the TMJC tissue repair process and ultimately help to solve clinical problems.

Bismuth Quantum Dot (Bi QD)/Polydimethylsiloxane (PDMS) Nanocomposites with Self-Cleaning and Antibacterial Activity for Dental Applications.

In the oral microenvironment, bacteria colonies are easily aggregated on the tooth-restoration surface, in the manner of a biofilm, which usually consists of heterogeneous structures containing clusters of a variety of bacteria embedded in an extracellular matrix, leading to serious recurrent caries. In this contribution, zero-dimensional (0D) bismuth (Bi) quantum dots (QDs) synthesized by a facile solvothermal method were directly employed to fabricate a Bi QD/polydimethylsiloxane (PDMS)-modified tooth by simple curing treatment. The result demonstrates that the as-fabricated Bi QD/PDMS-modified tooth at 37 °C for 120 min not only showed significantly improved hydrophobic performance with a water contact angle of 103° and 115° on the tooth root and tooth crown, respectively, compared to that (~20° on the tooth root, and ~5° on the tooth crown) of the pristine tooth, but also exhibited excellent antibacterial activity against S. mutans, superior biocompatibility, and biosafety. In addition, due to the highly photothermal effect of Bi QDs, the antibacterial activity of the as-fabricated Bi QD/PDMS-modified tooth could be further enhanced under illumination, even at a very low power density (12 mW cm-2). Due to the facile fabrication, excellent hydrophobicity, superior antibacterial activity, and biocompatibility and biosafety of the Bi QD/PDMS-modified tooth, it is envisioned that the Bi QD/PDMS-modified tooth with a fascinating self-cleaning and antibacterial performance can pave the way to new designs of versatile multifunctional nanocomposites to prevent secondary caries in the application of dental restoration.

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.

Investigation of three-rooted deciduous mandibular second molars in a Chinese population using cone-beam computed tomography.

BACKGROUND: To investigate the anatomic features of three-rooted deciduous mandibular second molars (DMSMs) in Chinese children by using cone-beam computed tomography (CBCT). METHODS: A total of 247 CBCT scans of Chinese children were selected and retrospectively analyzed. The occurrence, gender and side predilection of three-rooted DMSMs were examined. The pattern of concurrence of bilateral three-rooted DMSMs, and concurrence of three-rooted DMSM and three-rooted permanent mandibular first molar (PMFM) was analyzed by the concurrence rate and Spearman's rank correlation test. The geometric parameters of the disto-buccal (DB) and disto-lingual (DL) roots, including the vertical root length, level and angle of distal root furcation, angle of root curvature (by Schneider technique) and the spreading angle, were measured and compared to the three-rooted PMFMs (n = 42) from 100 randomly selected adult subjects. RESULTS: The occurrence of three-rooted DMSMs was 24.0% (54/225) calculated by individual, and 18.6% (88/472) by tooth. A significant right-side predilection was detected (23.0% vs 14.2%, p < 0.05), while gender predilection was not detected (p > 0.05). The bilateral concurrence rate was 49.0%, and Spearman's correlation test indicated a significant relationship between the antimetric teeth (rho = 0.609, p < 0.01); whereas a weak but significant co-relationship was detected between the three-rooted DMSM and three-rooted PMFM (right side: concurrence rate = 31.6%, rho = 0.325, p < 0.01; left side: concurrence rate = 23.0%, rho = 0.260, p < 0.01). The length of DL roots in the DMSMs was 7.4 ± 1.5 mm, and the curvature angle was 16.4 ± 11.3 degrees, which was significantly (both p < 0.01) lower than that of the three-rooted PMFMs (root length = 11.0 ± 1.3 mm; degrees of curvature = 34.2 ± 16.1 degrees), whereas the spreading angle of the DL root in DMSMs (34.6 ± 8.4 degrees) was significantly (p < 0.01) greater than in the PMFMs (26.8 ± 6.5 degrees). CONCLUSIONS: Three-rooted DMSMs have a high occurrence rate in the Chinese children with a right-side predilection, and they have a weak but statistically significant correlation with three-rooted PMFMs. The DL roots of DMSMs are shorter, less curved, and spreading more widely as compared with those in the three-rooted PMFMs.

Conditioned Medium From the Stem Cells of Human Exfoliated Deciduous Teeth Ameliorates Neuropathic Pain in a Partial Sciatic Nerve Ligation Model.

In neuropathic pain (NP), injury or diseases of the somatosensory system often result in highly debilitating chronic pain. Currently, there is no effective drug for the complete and definitive treatment of NP. We investigated the therapeutic potential of conditioned medium (CM) derived from stem cells from human exfoliated deciduous teeth (SHED-CM) against NP using a mouse partial sciatic nerve ligation (PSL) model. Abnormal pain sensation, such as tactile allodynia and hyperalgesia, can be caused by PSL. In the behavioral test, intravenous administration of SHED-CM greatly improved the PSL-induced hypersensitivity. We found that treatment with SHED-CM resulted in the recruitment of M2 macrophages in the injured sciatic nerve and ipsilateral L4/L5 dorsal root ganglion and suppressed microglial activation in the spinal cord. Notably, specific depletion of the anti-inflammatory M2 macrophages by mannosylated-Clodrosome markedly reduced the antinociceptive effect of SHED-CM. Intravenous administration of CM from M2 induced by SHED-CM (M2-CM) ameliorated the PSL-induced hypersensitivity. We found that M2-CM directly suppressed the expression of nociceptive receptors as well as proinflammatory mediators in Schwann cells. Taken together, our data suggest that SHED-CM ameliorates NP through the induction of the analgesic anti-inflammatory M2 macrophages. Thus, SHED-CM may be a novel therapeutic candidate for NP.

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.

2D MXene Ti3C2T x nanosheets in the development of a mechanically enhanced and efficient antibacterial dental resin composite.

The bacterial accumulation at the margins of dental resin composites is a main cause of secondary caries, which may further lead to prosthodontic failure. In this regard, this study for the first time incorporated 2D MXene Ti3C2Tx nanosheets (NSs) into epoxy resin at different mass ratios (0, 0.5, 1.0, and 2.0 wt%) by solution blending and direct curing for dental applications. Compared to the pure resin, the as-fabricated MXene/resin composite not only exhibited improved mechanical and abrasive results but also displayed gradually improved antibacterial activity with MXene loading which was further enhanced by illumination in natural light due to the high photothermal efficiency of MXene. In addition, the cytotoxicity result demonstrated that the MXene-modified resin did not cause severe damage to normal cells. This novel MXene/resin nanocomposite could pave the way for new designs for high-performance, multifunctional nanocomposites to effectively protect dental health in daily life.

Profile of the RNA in exosomes from astrocytes and microglia using deep sequencing: implications for neurodegeneration mechanisms.

Glial cells play an important role in signal transduction, energy metabolism, extracellular ion homeostasis and neuroprotection of the central nervous system. However, few studies have explained the potential effects of exosomes from glial cells on central nervous system health and disease. In this study, the genes expressed in exosomes from astrocytes and microglia were identified by deep RNA sequencing. Kyoto Encyclopedia of Genes and Genomes analysis indicated that several pathways in these exosomes are responsible for promoting neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and Huntington's disease. Gene ontology analysis showed that extracellular exosome, mitochondrion and growth factor activity were enriched in exosomes from the unique astrocyte group, while extracellular exosome and mitochondrion were enriched in exosomes from the unique microglia group. Next, combined with the screening of hub genes, the protein-protein interaction network analysis showed that exosomes from astrocytes influence neurodegenerative diseases through metabolic balance and ubiquitin-dependent protein balance, whereas exosomes from microglia influence neurodegenerative diseases through immune inflammation and oxidative stress. Although there were differences in RNA expression between exosomes from astrocytes and microglia, the groups were related by the hub genes, ubiquitin B and heat shock protein family A (Hsp70) member 8. Ubiquitin B appeared to be involved in pleiotropic regulatory functions, including immune regulation, inflammation inhibition, protein catabolism, intracellular protein transport, exosomes and oxidative stress. The results revealed the clinical significance of exosomes from glia in neurodegenerative diseases. This study was approved by the Animal Ethics Committee of Nantong University, China (approval No. S20180102-152) on January 2, 2018.

SUMO1 modification of IGF-1R combining with SNAI2 inhibited osteogenic differentiation of PDLSCs stimulated by high glucose.

BACKGROUND: Periodontal disease, an oral disease characterized by loss of alveolar bone and progressive teeth loss, is the sixth major complication of diabetes. It is spreading worldwide as it is difficult to be cured. The insulin-like growth factor 1 receptor (IGF-1R) plays an important role in regulating functional impairment associated with diabetes. However, it is unclear whether IGF-1R expression in periodontal tissue is related to alveolar bone destruction in diabetic patients. SUMO modification has been reported in various diseases and is associated with an increasing number of biological processes, but previous studies have not focused on diabetic periodontitis. This study aimed to explore the role of IGF-1R in osteogenic differentiation of periodontal ligament stem cells (PDLSCs) in high glucose and control the multiple downstream damage signal factors. METHODS: PDLSCs were isolated and cultured after extraction of impacted teeth from healthy donors or subtractive orthodontic extraction in adolescents. PDLSCs were cultured in the osteogenic medium with different glucose concentrations prepared by medical 5% sterile glucose solution. The effects of different glucose concentrations on the osteogenic differentiation ability of PDLSCs were studied at the genetic and cellular levels by staining assay, Western Blot, RT-PCR, Co-IP and cytofluorescence. RESULTS: We found that SNAI2, RUNX2 expression decreased in PDLSCs cultured in high glucose osteogenic medium compared with that in normal glucose osteogenic medium, which were osteogenesis-related marker. In addition, the IGF-1R expression, sumoylation of IGF-1R and osteogenic differentiation in PDLSCs cultured in high glucose osteogenic medium were not consistent with those cultured in normal glucose osteogenic medium. However, osteogenic differentiation of PDLCSs enhanced after adding IGF-1R inhibitors to high glucose osteogenic medium. CONCLUSION: Our data demonstrated that SUMO1 modification of IGF-1R inhibited osteogenic differentiation of PDLSCs by binding to SNAI2 in high glucose environment, a key factor leading to alveolar bone loss in diabetic patients. Thus we could maximize the control of multiple downstream damage signaling factors and bring new hope for alveolar bone regeneration in diabetic patients.

Prediction of pregnancy outcome in fresh in vitro fertilization/intracytoplasmic sperm injection treatment in patients with poor ovarian reserve.

We retrospectively analyzed the clinical data from 39,185 cycles who undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) in the First People's Hospital of Shangqiu, these poor ovarian reserve patients were further categorized into the "unexpected" group (n=3337) and the "expected" group (n=2667) based on POSEIDON classification. In "expected" group, logistic regression analysis showed that female age (OR 0.920; 95% C.I 0.902~0.939; P < 0.001), treatment cycles (OR 0.693; 95% C.I 0.560~0.859; P = 0.001), duration of Gn administered (OR 1.077; 95% C.I 1.027~1.129; P = 0.002) and transferable embryos (OR 1.377; 95% C.I 1.319~1.437; P < 0.001) is independent predictive factors of live birth. In "expected" group, logistic regression analysis showed that female age (OR 0.874; 95% C.I 0.848~0.900; P < 0.001), AFC (OR 1.285; 95% C.I 1.131~1.461; P < 0.001), total dosage of Gn administered (OR 1.001; 95% C.I 1.000~1.002; P < 0.001), duration of Gn administered (OR 0.784; 95% C.I 0.639~0.961; P = 0.019), MII number (OR 0.841; 95% C.I 0.717~0.986; P = 0.032) and transferable embryos (OR 2.057; 95% C.I 1.762~2.400; P < 0.001) is independent predictive factors of live birth. We also established a smooth curve fit to predict the probability of live birth among the POSEIDON "unexpected" and "expected" group. These independent predictive factors on the pregnancy outcome of IVF/ICSI and the successful establishment of smooth curve fit can provide valuable reference for treats poor ovarian reserve patients in clinical work.

The threshold effect of factors associated with spontaneous abortion in human-assisted reproductive technology.

We explored the independent risk factors associated with cases of spontaneous abortion in infertile patients treated with human-assisted reproductive technology (ART) and established a smooth curve fit and perform a threshold effect analysis can provide guidance and a valuable reference for predicting the probability of spontaneous abortion. This was a retrospective cohort study of 16,097 patients successfully conceived with ART in Shangqiu First People's Hospital from June 2013 to December 2018. Overall, 2,378 (14.77%) had an abortion and 13,719 (85.23%) did not have an abortion. Multivariate logistic regression analysis showed that female age (OR 1.050; 95% CI 1.032-1.069; P < 0.001), male age (OR 1.100; 95% CI 1.086-1.115; P < 0.001), follicular-stimulating hormone (OR 1.049; 95% CI 1.022-1.076; P < 0.001), anti-Mullerian hormone (OR 0.893; 95% CI 0.862-0.925; P < 0.001) and the number of fetuses at pregnancy diagnosis were independent factors associated with spontaneous abortion. The threshold effect analysis found that when female age > 32 years (cut-off point) old, age and the risk of spontaneous abortion were positively correlated. When follicular-stimulating hormone > 6.1 IU/L (cut-off point), follicular-stimulating hormone was positively correlated with the occurrence of spontaneous abortion, When anti-Mullerian hormone ≤ 3.1 ng/mL (cut-off point), anti-Mullerian hormone was negatively correlated with the occurrence of spontaneous abortion and there was a linear positive correlation between antral Follicle Counting and live birth. In addition, the older the male age, the higher the incidence of abortion. The smooth curve fit and threshold effect analyses can provide a more detailed estimate of the probability of spontaneous abortion for pregnant couples.

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.

MicroRNA-125a-3p participates in odontoblastic differentiation of dental pulp stem cells by targeting Fyn.

Fyn is a member of the protein tyrosine kinase family and its overexpression is associated with various types of inflammation. MicroRNAs can regulate the expression of target genes and play an important role in varied physiological and pathological processes. Based on the important role of Fyn and microRNA-125a-3p (miR-125a-3p) in inflammation, and combined with the bioinformatics studies, we performed in this study and chose miR-125a-3p as the focus of our research. During the progression of inflammation, we found that the expression of miR-125a-3p was decreased while the expression of Fyn was up-regulated. Fyn formed a complex with Neuropilin-1, which inhibited odontoblastic differentiation and expanded inflammatory responses through nuclear factor-κB signal pathways in dental pulp stem cells (DPSCs). These findings suggested that miR-125a-3p plays an important role in odontoblastic differentiation of DPSCs by targeting Fyn, implying its therapeutic potential in dental caries.

Dysfunction of MiR-148a-NRP1 Functional Axis Suppresses Osteogenic Differentiation of Periodontal Ligament Stem Cells Under Inflammatory Microenvironment.

Periodontitis is a chronic inflammatory disease that can lead to the loss of periodontal bone tissue. The osteogenic potential of periodontal ligament stem cells (PDLSCs) is significantly decreased in periodontitis microenvironment. However, the mechanism is still unclear. We used Porphyromonas gingivalis lipopolysaccharide (LPS) as a stimulator of PDLSCs to mimic the periodontal inflammatory environment. The mineralization capability was restrained in LPS-stimulated PDLSCs, and the level of miR-148a increased, while the level of Neuropilin 1 (NRP1) decreased. Downregulation of miR-148a could reverse the osteogenesis deficiency of PDLSCs under LPS treatment. In addition, the expression of miR-148a in PDLSCs was negatively correlated with the expression of NRP1. Furthermore, overexpression of NRP1 upregulated the osteogenesis ability of LPS-stimulated PDLSCs, while inhibition of NRP1 eliminated the stimulative effect of miR-148a inhibitor on osteogenic differentiation. These data illustrated that the inflammatory environment mimicked by LPS inhibits osteogenesis by upregulation of miR-148a and subsequent downregulation of NRP1. We also found, compared to healthy periodontal tissues, miR-148a level increased, while NRP1 level decreased in periodontitis tissues. These two phenomena also exist in PDLSCs that come from the upper two types of tissues. To summarize, the decline of osteogenic potential of PDLSCs under inflammatory condition of periodontitis is related to miR-148a/NRP1 functional axis. This study may provide a novel strategy in the molecular aspect for the therapy of periodontitis.

Periodontal disease in Chinese patients with rheumatoid arthritis: A case-control study.

OBJECTIVE: To evaluate the prevalence and severity of periodontal disease in Chinese rheumatoid arthritis patients. SUBJECTS AND METHODS: This cross-sectional study included 128 RA and 109 healthy controls. Two dentists conducted periodontal status including Plaque index (PI), Gingival index (GI), pocket probing depths (PPDs), Clinical attachment level (CAL) and Bleeding on probing (BOP) independently. Sociodemographic, lifestyle, clinical parameters and use of medication were assessed. Data were analyzed by Student's t test, χ2 test, Wilcoxin-Mann- Whitney's test, Correlational Analysis, univariate or multivariate logistic regression. RESULTS: The periodontal status was significantly worse in RA, especially the condition of dental and gingival status. RA had 4.68-fold. After adjusted potential risk factors, RA had 10.26-fold. The independent variable related to GI was DAS28 (p = .05) negatively, to the contrary, ESR (p = .013) was positively associated; the independent variable positively and related to periodontitis was educational level (p = .021) and anti-CCP positivity (p = .002). Through multivariate logistic regression, age and swollen joint were the independent variable related to periodontitis of RA (OR 1.087, p = .044) and (OR 1.560, p = .008) respectively. CONCLUSIONS: Chinese RA patients show higher odds of PD. It is important to take early interventions in combination with medical therapy.

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.

Role of mTOR complex in IGF-1 induced neural differentiation of DPSCs.

Recent studies have demonstrated that IGF-1 modulates the pluripotent differentiation of dental pulp stem cells (DPSCs). Although mTOR pathway activation has been showed as responsible for IGF-1 induced pluripotent differentiation, the mechanism that the IGF-1-mTOR pathway induces the neural differentiation of DPSCs is still unclear. In our research, we have demonstrated that 0-10 ng/mL IGF-1 had no obvious effect on the proliferation of DPSCs, but IGF-1 nonetheless enhances the neural differentiation of DPSCs in a dose-dependent manner. Simultaneously, we found that phosphorylated mTOR was up-regulated, which indicated the involvement of mTOR in the process. Rapamycin, an inhibitor of mTOR activity, can reverse the effect of DPSCs stimulated by IGF-1. Next, we studied the role of mTORC1 and mTORC2, two known mTOR complexes, in the neural differentiation of DPSCs. We found that inhibition of mTORC1 can severely restricts the neural differentiation of DPSCs. However, inhibition of mTORC2 has the opposite effect. This latter effect disappears when both rictor and mTOR are inhibited, showing that the mTORC2 effect is mTORC1 dependent. This study has expanded the role of mTOR in DPSCs neural differentiation regulated by IGF-1.