Search

Background and Objectives: The alveolar bone remodelling promoted by reasonable mechanical force triggers orthodontic tooth movement (OTM). The generation of osteoclasts is essential in this process. However, the mechanism of mechanical force mediating osteoclast differentiation remains elusive. Small nucleolar RNA host gene 5 (SNHG5), which was reported to mediate the osteogenic differentiation of bone marrow mesenchymal stem cells in our previous study, was downregulated in human periodontal ligament cells (hPDLCs) under mechanical force. At the same time, the RANKL/OPG ratio increased. Based on this, we probed into the role of SNHG5 in osteoclast formation during OTM and the relevant mechanism., Materials and Methods: SNHG5 and the RANKL/OPG ratio under different compressive forces were detected by western blotting (WB) and qRT-PCR. Impact of overexpression or knockdown of SNHG5 on osteoclast differentiation was detected by qRT-PCR, WB and transwell experiments. The combination of SNHG5 and C/EBPβ was verified by RNA immunoprecipitation and RNA pull-down assays. The expression of SNHG5 and osteoclast markers in gingiva were analysed by qRT-PCR and the paraffin sections of periodontal tissues were used for histological analysis., Results: Compressive force downregulated SNHG5 and upregulated the RANKL/OPG ratio in hPDLCs. Overexpression of SNHG5 inhibited RANKL's expression and osteoclast differentiation. SNHG5 combined with C/EBPβ, a regulator of osteoclast. The expression of SNHG5 in periodontal tissue decreased during OTM., Conclusion: SNHG5 inhibited osteoclast differentiation during OTM, achieved by affecting RANKL secretion, which may provide a new idea to interfere with bone resorption during orthodontic treatment., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: To assess the tooth movement trends during the three stages of maxillary dentition distalization with clear aligners (CA) and to compare the efficacy of different mini-screw anchorage systems., Materials and Methods: Three-dimensional (3D) finite element models of three anchorage systems (A, control group; B, buccal mini-screw anchorage group; C, palatal mini-screw anchorage group) were established. Three stages of simulating maxillary dentition distalization with CA included maxillary molar distalization (stage 1), maxillary premolar distalization (stage 2) and maxillary anterior teeth retraction (stage 3). Therefore, a total of nine models were constructed to analyse the 3D displacement of maxillary teeth during the distalization process., Results: The displacement pattern of maxillary dentition during distalization was similar across the three groups, but with varying magnitudes. During stage 1, groups B and C exhibited greater amounts of molar distalization compared to group A. Group C also demonstrated the least amount of labial movement of the maxillary central incisor compared to the other two groups. During stage 2, the mesial displacement of the maxillary first molar was less significant in groups B and C than in group A. In the final stage, group C exhibited a greater amount of maxillary anterior retraction compared to groups A and B., Conclusion: The palatal mini-screw anchorage system was effective in reducing anchorage loss and improving the efficacy of maxillary dentition distalization with CA., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Orthodontic tooth movement (OTM) is a dynamic equilibrium of bone remodeling, involving the osteogenesis of new bone and the osteoclastogenesis of old bone, which is mediated by mechanical force. Periodontal ligament stem cells (PDLCSs) in the periodontal ligament (PDL) space can transmit mechanical signals and regulate osteoclastogenesis during OTM. KAT6A is a histone acetyltransferase that plays a part in the differentiation of stem cells. However, whether KAT6A is involved in the regulation of osteoclastogenesis by PDLSCs remains unclear., Results: In this study, we used the force-induced OTM model and observed that KAT6A was increased on the compression side of PDL during OTM, and also increased in PDLSCs under compression force in vitro. Repression of KAT6A by WM1119, a KAT6A inhibitor, markedly decreased the distance of OTM. Knockdown of KAT6A in PDLSCs decreased the RANKL/OPG ratio and osteoclastogenesis of THP-1. Mechanistically, KAT6A promoted osteoclastogenesis by binding and acetylating YAP, simultaneously regulating the YAP/TEAD axis and increasing the RANKL/OPG ratio in PDLSCs. TED-347, a YAP-TEAD4 interaction inhibitor, partly attenuated the elevation of the RANKL/OPG ratio induced by mechanical force., Conclusion: Our study showed that the PDLSCs modulated osteoclastogenesis and increased the RANKL/OPG ratio under mechanical force through the KAT6A/YAP/TEAD4 pathway. KAT6A might be a novel target to accelerate OTM., (© 2024. The Author(s).)

Wound healing is a complex challenge that demands urgent attention in the clinical realm. Efficient angiogenesis is a pivotal factor in promoting wound healing. microRNA-146a (miR-146a) inhibitor has angiogenic potential in the periodontal ligament. However, free microRNAs (miRNAs) are poorly delivered into cells due to their limited tissue specificity and low intracellular delivery efficiency. To address this hurdle, we developed a nanocarrier for targeted delivery of the miR-146a inhibitor into endothelial cells. It is composed of a polyethylenimine (PEI)-modified mesoporous silica nanoparticle (MSN) core and a pentapeptide (YIGSR) layer that recognizes endothelial cells. In vitro, we defined that the miR-146a inhibitor and adiponectin (ADP) can modulate angiogenesis and the remodeling of periodontal tissues by activating the ERK and Akt signaling pathways. Then, we confirm the specificity of YIGSR to endothelial cells, and importantly, the nanocarrier effectively delivers the miR-146a inhibitor into endothelial cells, promoting angiogenesis. In a C57 mouse skin wound model, the miR-146a inhibitor is successfully delivered into endothelial cells at the wound site using the nanocarrier, resulting in the formation of new blood vessels with strong CD31 expression. Additionally, no significant differences are found in the expression levels of inflammatory markers interleukin-6 and tumor necrosis factor-α. This outcome not only brings new strategies for angiogenesis but also exhibits broader implications for bone remodeling and wound healing. The breakthrough holds significance for future research and clinical interventions.

A novel model called error loss network (ELN) is proposed to build an error loss function for supervised learning. The ELN is similar in structure to a radial basis function (RBF) neural network, but its input is an error sample and output is a loss corresponding to that error sample. That means the nonlinear input-output mapper of the ELN creates an error loss function. The proposed ELN provides a unified model for a large class of error loss functions, which includes some information-theoretic learning (ITL) loss functions as special cases. The activation function, weight parameters, and network size of the ELN can be predetermined or learned from the error samples. On this basis, we propose a new machine learning paradigm where the learning process is divided into two stages: first, learning a loss function using an ELN; second, using the learned loss function to continue to perform the learning. Experimental results are presented to demonstrate the desirable performance of the new method.

The altered expression of long noncoding RNAs (lncRNAs) is associated with human carcinogenesis. We performed a high-throughput analysis of lncRNA expression in strictly selected pairs of metastatic head and neck squamous cell carcinoma (HNSCC) and non-metastatic HNSCC samples. We identified a novel lncRNA, which was highly expressed in metastatic HNSCC, named Metastasis Associated Squamous Cell Carcinoma 1 (MASCC1), for further study. Using qRT-PCR, we further compared MASCC1 expression in 60 HNSCC samples. The results show that high expression of MASCC1 in patients with HNSCC was related to poor prognosis. In vitro, MASCC1 knockdown (KD) inhibited HNSCC proliferation, migration, invasion, and tumor sphere formation, while promoting apoptosis. In vivo, MASCC1 KD inhibited HNSCC growth and lymph node metastasis. Mechanistically, MASCC1 acted as a competing endogenous RNA (ceRNA) by binding to miR-195, subsequently regulating the expression of Cyclin D1, BCL-2, and YAP1. Moreover, miR-195 overexpression rescued the effects of MASCC1 on the biological behaviors of HNSCC. Taken together, our results suggest that MASCC1 is a novel oncogene that can predict the prognosis of patients with HNSCC and is a potential therapeutic target for HNSCC intervention.

Craniofacial bone defects induced by congenital malformations, trauma, or diseases frequently challenge the orthodontic or restorative treatment. Stem cell-based bone regenerative approaches emerged as a promising method to resolve bone defects. Microenvironment physical cues, such as the matrix elastic modulus or matrix topography, regulate stem cell differentiation via multiple genes. We constructed gelatin methacryloyl (GelMA), a well-known scaffold, to investigate the impact of elastic modulus on osteogenic differentiation in a three-dimensional environment. Confocal microscope was used to observe and assess the condensates fission and fusion. New bone formation was evaluated by micro-computed tomography at 6 weeks in calvarial defect rat. We found that the light curing increased elastic modulus of GelMA, and the pore size of GelMA decreased. The expression of osteogenic markers was inhibited in hBMSCs cultured in the low-elastic-modulus GelMA. In contrast, the expression of YAP, TAZ and TEAD was increased in the hBMSCs in the low-elastic-modulus GelMA. Furthermore, YAP assembled via liquid-liquid phase separation (LLPS) into condensates that were sensitive to 1'6-hexanediol. YAP recruit TAZ and TEAD4, but not RUNX2 into the condensates. In vivo, we also found that hBMSCs in high-elastic-modulus GelMA was more apt to form new bone. This study provides new insight into the mechanism of osteogenic differentiation. Reagents that can regulate the elastic modulus of substrate or LLPS may be applied to promote bone regeneration., (© 2023 Wiley Periodicals LLC.)

Minimum error entropy with fiducial points (MEEF) has received a lot of attention, due to its outstanding performance to curb the negative influence caused by non-Gaussian noises in the fields of machine learning and signal processing. However, the estimate of the information potential of MEEF involves a double summation operator based on all available error samples, which can result in large computational burden in many practical scenarios. In this paper, an efficient quantization method is therefore adopted to represent the primary set of error samples with a smaller subset, generating a quantized MEEF (QMEEF). Some basic properties of QMEEF are presented and proved from theoretical perspectives. In addition, we have applied this new criterion to train a class of linear-in-parameters models, including the commonly used linear regression model, random vector functional link network, and broad learning system as special cases. Experimental results on various datasets are reported to demonstrate the desirable performance of the proposed methods to perform regression tasks with contaminated data., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Repair of orthodontic external root resorption and periodontal tissue dysfunction induced by mechanical force remains a clinical challenge. Cementoblasts are vital in cementum mineralization, a process important for restoring damaged cementum. Despite autophagy plays a role in mineralization under various environmental stimuli, the underlying mechanism of autophagy in mediating cementoblast mineralization remains unclear. Here we verified that murine cementoblasts exhibit compromised mineralization under compressive force. Autophagy was indispensable for cementoblast mineralization, and autophagic activation markedly reversed cementoblast mineralization and prevented cementum damage in mice during tooth movement. Subsequently, messenger RNA sequencing analyses identified periostin (Postn) as a mediator of autophagy and mineralization in cementoblasts. Cementoblast mineralization was significantly inhibited following the knockdown of Postn. Furthermore, Postn silencing suppressed Wnt signaling by modulating the stability of β-catenin. Together our results highlight the role of autophagy in cementoblast mineralization via Postn/β-catenin signaling under compressive force and may provide a new strategy for the remineralization of cementum and regeneration of periodontal tissue., (© 2023 Wiley Periodicals LLC.)

Treatments for malignant bone tumors are urgently needed to be developed due to the dilemma of precise resection of tumor tissue and subsequent bone defects. Although polyether-ether-ketone (PEEK) has widely attracted attention in the orthopedic field, its bioinertness and poor osteogenic properties significantly restrict its applications in bone tumor treatment. To tackle the daunting issue, we use a hydrothermal technique to fabricate novel PEEK scaffolds modified with molybdenum disulfide (MoS 2 ) nanosheets and hydroxyapatite (HA) nanoparticles. Our dual-effect synergistic PEEK scaffolds exhibit perfect photothermal therapeutic (PTT) property dependent on molybdous ion (Mo 2+ ) concentration and laser power density, superior to conventional PEEK scaffolds. Under near-infrared (NIR) irradiation, the viability of MG63 osteosarcoma cells is significantly reduced by modified PEEK scaffolds, indicating a tumor-killing potential in vitro. Furthermore, the incorporation of HA nanoparticles on the surface of PEEK bolsters proliferation and adherence of MC3T3-E1 cells, boosting mineralization for further bone defect repair. The results of micro-computed tomography (micro-CT) and histological analysis of 4-week treated rat femora demonstrate the preeminent photothermal and osteogenesis capacity of 3D-printed modified scaffolds in vivo. In conclusion, the dual-effect synergistic orthopedic implant with photothermal anticancer property and osteogenic induction activity strikes a balance between tumor treatment and bone development promotion, offering a promising future therapeutic option., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Objectives: Mammalian palatogenesis is a highly regulated morphogenetic process to form the intact roof of the oral cavity. Long noncoding RNAs (lncRNAs) and mRNAs participate in numerous biological and pathological processes, but their roles in palatal development and causing orofacial clefts (OFC) remain to be clarified., Methods: Palatal tissues were separated from ICR mouse embryos at four stages (E10.5, E13.5, E15, and E17). Then, RNA sequencing (RNA-seq) was used. Various analyses were performed to explore the results. Finally, hub genes were validated via qPCR and in situ hybridization., Results: Starting from E10.5, the expression of cell adhesion genes escalated in the following stages. Cilium assembly and ossification genes were both upregulated at E15 compared with E13.5. Besides, the expression of cilium assembly genes was also increased at E17 compared with E15. Expression patterns of three lncRNAs (H19, Malat1, and Miat) and four mRNAs (Cdh1, Irf6, Grhl3, Efnb1) detected in RNA-seq were validated., Conclusions: This study provides a time-series expression landscape of mRNAs and lncRNAs during palatogenesis, which highlights the importance of processes such as cell adhesion and ossification. Our results will facilitate a deeper understanding of the complexity of gene expression and regulation during palatogenesis., (© 2022 Wiley Periodicals LLC.)

Self-distillation methods utilize Kullback-Leibler divergence (KL) loss to transfer the knowledge from the network itself, which can improve the model performance without increasing computational resources and complexity. However, when applied to salient object detection (SOD), it is difficult to effectively transfer knowledge using KL. In order to improve SOD model performance without increasing computational resources, a non-negative feedback self-distillation method is proposed. Firstly, a virtual teacher self-distillation method is proposed to enhance the model generalization, which achieves good results in pixel-wise classification task but has less improvement in SOD. Secondly, to understand the behavior of the self-distillation loss, the gradient directions of KL and Cross Entropy (CE) loss are analyzed. It is found that KL can create inconsistent gradients with the opposite direction to CE in SOD. Finally, a non-negative feedback loss is proposed for SOD, which uses different ways to calculate the distillation loss of the foreground and background respectively, to ensure that the teacher network transfers only positive knowledge to the student. The experiments on five datasets show that the proposed self-distillation methods can effectively improve the performance of SOD models, and the average F β is increased by about 2.7% compared with the baseline network., Competing Interests: The authors declare there are no competing interests., (©2023 Chen et al.)

Objectives: This study investigated the role of lncRNA growth arrest-specific transcript 5 (GAS5) in the inflammatory response of periodontal ligament stem cells (PDLSCs) during periodontitis with attempts to its possible mechanisms., Materials and Methods: Gingiva samples were collected from healthy people and patients with periodontitis. The ligature-induced periodontitis model was established in mice. Cell transfection was utilized to knock down and overexpress GAS5 in PDLSCs. Quantitative real-time polymerase chain reaction (qRT-PCR) and fluorescence in situ hybridization were performed to detect the GAS5 expression. In combination with high-throughput sequencing technology, qRT-PCR, Western blotting, and immunofluorescence were performed to detect the effects of GAS5 on cytokines and proteins in the NF-κB pathway., Results: GAS5 expression decreased in PDLSCs subjected to compressive force. GAS5 expression was downregulated in the gingiva tissues from patients with periodontitis. Consistent with the results of clinical samples, GAS5 expression decreased in the mouse ligature-induced periodontitis model. GAS5 expression was downregulated in PDLSCs under tumour necrosis factor (TNF)-α stimulation. Knockdown and overexpression of GAS5 increased and decreased the expression of cytokines induced by TNF-α in PDLSCs, respectively. The sequencing results showed that overexpressing GAS5 was related to genes in the NF-κB pathway. Overexpressing GAS5 alleviated p65 phosphorylation and inhibited the entry of p65 into the nucleus in the TNF-α activated NF-κB pathway, whereas GAS5 knockdown resulted in contrasting results., Conclusions: GAS5 alleviated the expression of cytokines in PDLSCs by inhibiting activation of the TNF-α-mediated NF-κB pathway. These findings provide new insight into the regulation of the PDLSCs inflammation response., (© Crown copyright 2022.)

Mechanical stress regulates various cellular functions like cell inflammation, immune responses, proliferation, and differentiation to maintain tissue homeostasis. However, the impact of mechanical signals on macrophages and the underlying mechanisms by which mechanical force regulates bone remodeling during orthodontic tooth movement remain unclear. NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome has been reported to promote osteoclastic differentiation to regulate alveolar bone resorption. But the relationship between the compressive force and NLRP3 inflammasome in macrophages remains unknown. In this study, immunohistochemical staining results showed elevated expression of NLRP3 and interleukin-1β, as well as an increased number of macrophages expressing NLRP3, on the compression side of the periodontal tissues, after force application for 7 days. Furthermore, the number of tartrate-resistant acid phosphatase-positive osteoclasts, and the mRNA and protein expression levels of osteoclast-related genes in the periodontal tissue decreased in the Nlrp3 -/- mice compared to the WT mice group after orthodontic movement. In vitro mechanical force activates the NLRP3 inflammasome and inhibits autophagy. Intraperitoneal injection of the autophagy inhibitor 3-methyladenine in Nlrp3 -/- mice promoted orthodontic tooth movement. This result indicates that the absence of NLRP3 inflammasome activation can be partially compensated for by autophagy inhibitors. Mechanistically, force-induced activation of the NLRP3 inflammasome in macrophages via the cGAS/P2X7R axis. In conclusion, compressive force regulates orthodontic tooth movement via activating the NLRP3 inflammasome., (© 2022 Federation of American Societies for Experimental Biology.)

Many circular RNAs (circRNAs) involved in the osteogenesis of human bone marrow mesenchymal stem cells (hBMSCs) have recently been discovered. The role of circHIPK3 in osteogenesis has yet to be determined. Cell transfection was conducted using small-interfering RNAs (siRNAs). Expression of osteogenic markers were detected by quantitative reverse transcription-polymerase chain reaction, western blotting analysis, and immunofluorescence staining. Ectopic bone formation models in nude mice were used to examined the bone formation ability in vivo. The autophagy flux was examined via western blotting analysis, immunofluorescence staining and transmission electron microscopy analysis. RNA immunoprecipitation (RIP) analysis was carried out to analyze the binding between human antigen R (HUR) and circHIPK3 or autophagy-related 16-like 1 (ATG16L1). Actinomycin D was used to determine the mRNA stability. Our results demonstrated that silencing circHIPK3 promoted the osteogenesis of hBMSCs while silencing the linear mHIPK3 did not affect osteogenic differentiation, both in vivo and in vitro. Moreover, we found that knockdown of circHIPK3 activated autophagy flux. Activation of autophagy enhanced the osteogenesis of hBMSCs and inhibition of autophagy reduced the osteogenesis through using autophagy regulators chloroquine and rapamycin. We also discovered that circHIPK3 and ATG16L1 both bound to HUR. Knockdown of circHIPK3 released the binding sites of HUR to ATG16L1, which stabilized the mRNA expression of ATG16L1, resulting in the upregulation of ATG16L1 and autophagy activation. CircHIPK3 functions as an osteogenesis and autophagy regulator and has the potential for clinical application in the future., (© 2022 Federation of American Societies for Experimental Biology.)

Aim: We investigated the role of long non-coding RNAs and small nucleolar RNA host gene 5 (SNHG5) in the pathogenesis of periodontitis., Materials and Methods: A ligature-induced periodontitis mouse model was established, and gingival tissues were collected from patients with periodontitis and healthy controls. Inflammatory cytokines were detected using quantitative reverse transcription-polymerase chain reaction and western blotting analyses. Direct interactions between SNHG5 and p65 were detected by RNA pull-down and RNA immunoprecipitation assays. Micro-computed tomography, haematoxylin and eosin staining, and immunohistochemical staining were used to measure periodontal bone loss., Results: SNHG5 expression was down-regulated in human and mouse periodontal tissues compared to that in the healthy controls. In vitro experiments demonstrated that SNHG5 significantly ameliorated tumour necrosis factor α-induced inflammation. Mechanistically, SNHG5 directly binds to the nuclear factor-kappa B (NF-κB) p65 subunit and inhibits its translocation, thereby suppressing the NF-κB signalling pathway activation and reducing the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing three inflammasome expression. Locally injecting si-SNHG5 aggravated the periodontal destruction., Conclusion: This study revealed that SNHG5 mediates periodontal inflammation through the NF-κB signalling pathway, providing a potential therapeutic target for periodontitis treatment., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Recently, polarization-based models for camouflaged object segmentation have attracted research attention. However, to construct this camouflaged object segmentation model, the main challenge is to effectively fuse polarization and light intensity features. Therefore, we propose a multi-modal camouflaged object segmentation method via gated fusion. First, the spatial positioning module is designed to perform channel calibration and global spatial attention alignment between polarization mode and light intensity mode from high-level feature representation to locate object positioning accurately. Then, the gated fusion module (GFM) is designed to selectively fuse the object information contained in the polarization and light intensity features. Among them, semantic information of location features is introduced in the GFM to guide each mode to aggregate dominant features. Finally, the features of each layer are aggregated to obtain an accurate segmentation result map. At the same time, considering the lack of public evaluation and training data on light intensity-polarization (I-P) camouflaged detection, we build the light I-P camouflaged detection dataset. Experimental results demonstrate that our proposed method outperforms other typical multi-modal segmentation methods in this dataset.

The age range of 3−6 years is considered as a critical period in developing and learning fundamental motor skills (FMS). To make the formulation of future FMS guidance programs more targeted, we examined gender differences in children’s FMS proficiency using a meta-analysis. Structured electronic databases including PubMed, Scopus and Web of Science were systematically searched using key terms, and the Joanna Briggs Institute (JBI) was used to assess the quality of included literature. Finally, 38 articles (39 studies) met the pre-specified inclusion criteria. The results showed that boys had higher proficiency in total FMS and object control skills than girls (SMD = 0.17 (95% CI 0.03, 0.31), p = 0.02; SMD = 0.48 (95% CI 0.38, 0.58), p < 0.00001), and gender differences in locomotor skill proficiency approached significance, trending in favor of girls (SMD = −0.07 (95 % CI −0.15, 0.01), p = 0.09, I2 = 66%). Meta-regression shows that age is associated with gender differences in object control skills (p < 0.05). In addition, through subgroup analysis, we found that boys’ advantage in object control skills increased with age (3 years: SMD = 0.27 (95% CI 0.00, 0.54), p < 0.00001; 4 years: SMD = 0.58 (95% CI 0.38, 0.77), p < 0.00001; 5 years: SMD = 0.59 (95% CI 0.31, 0.88), p < 0.00001; 6 years: SMD = 0.81 (95% CI 0.61, 1.01), p < 0.00001). In this meta-analysis, we found gender differences in FMS levels in children aged 3−6 years. Notably, gender differences in skill proficiency in object control were influenced by age. We recommend focusing on and developing girls’ object control skills starting at age 3.

Background: Identifying the factors affecting osteoblast differentiation of periodontal ligament cells (PDLCs) can help enhance the regeneration of periodontal tissue. LncRNA plasmacytoma variant translocation 1 (lncPVT1) is an important regulatory factor involved in many biological processes, but its role in osteogenesis remains unclear., Methods: Expressions of osteogenic markers were detected by quantitative reverse transcription polymerase chain reaction and Western blot analysis. Alkaline phosphatase staining was conducted for early osteoblast differentiation and alizarin red S staining was used for mineral deposition. RNA sequencing was used to identify the miRNAs regulated by lncPVT1 during osteogenesis. Cell transfection was used to overexpress or knockdown lncPVT1 and miR-10a-5p. Dual luciferase reporter assays were conducted to analyze the binding of miR-10a-5p to brain-derived neurotrophic factor (BDNF)., Results: LncPVT1 was significantly increased during osteogenic induction of PDLCs. Overexpression of lncPVT1 promoted osteogenesis, whereas lncPVT1 knockdown inhibited this process. RNA sequencing showed that miR-10a-5p expression was significantly increased after lncPVT1 knockdown. RNA immunoprecipitation assay further demonstrated the binding potential of lncPVT1 and miR-10a-5p. MiR-10a-5p inhibited the osteogenesis of PDLCs, and partially reversed the stimulatory effects of lncPVT1. Subsequently, we identified a predicted binding site for miR-10a-5p on BDNF and confirmed it using dual luciferase reporter assays. Moreover, lncPVT1 upregulated the expression of BDNF, whereas miR-10a-5p downregulated BDNF expression. BDNF promoted osteogenesis and partially rescued the si-lncPVT1-mediated inhibition of PDLCs osteogenic differentiation., Conclusions: LncPVT1 positively regulated the osteogenic differentiation of PDLCs via miR-10a-5p and BDNF. Our results provide a promising target for enhancing the osteogenic potential of PDLCs., (© 2021 American Academy of Periodontology.)

Background: A series of biochemical responses, including hypoxia and aseptic inflammation, occur in periodontal ligament cells (PDLCs) during periodontal tissue remodeling of orthodontic tooth movement (OTM). However, the role of long non-coding RNA (lncRNA) in these responses is still largely unknown. We investigated the role of the lncRNA SNHG8 in hypoxic and inflammatory responses during OTM and explored the underlying mechanisms., Methods: The expression pattern of SNHG8, and hypoxic and inflammatory responses under compressive force were analyzed by qRT-PCR, immunohistochemistry, and western blotting, in vivo and in vitro. The effect of overexpression or knockdown of SNHG8 on the nuclear factor-kappaB (NF-κB) pathway was evaluated. RNA sequencing was performed for mechanistic analysis. The interaction between SNHG8 and hypoxia-inducible factor (HIF)-1α was studied using catRAPID, RNA immunoprecipitation, and RNA pulldown assays. The effect of the SNHG8-HIF-1α interaction on the NF-κB pathway was determined by western blotting., Results: The NF-κB pathway was activated, and HIF-1α release was stabilized, in PDLCs under compressive force as well as in OTM model rats. The SNHG8 level markedly decreased both in vivo and in vitro. Overexpression of SNHG8 decreased the expression levels of inflammatory cytokines, the phosphorylation of p65, and the degradation of IκBα in PDLCs, whereas knockdown of SNHG8 reversed these effects. Mechanically, RNA sequencing showed that differentially expressed genes were enriched in cellular response to hypoxia after SNHG8 overexpression. SNHG8 binds to HIF-1α, thus preventing HIF-1 from activating downstream genes, including those related to the NF-κB pathway., Conclusion: SNHG8 binds to HIF-1α. During OTM, the expression of SNHG8 dramatically decreased, releasing free functional HIF-1α and activating the downstream NF-κB pathway. These data suggest a novel lncRNA-regulated mechanism during periodontal tissue remodeling in OTM., (© 2022. The Author(s).)

Background: The treatment of bone loss has posed a challenge to clinicians for decades. Thus, it is of great significance to identify more effective methods for bone regeneration. However, the role and mechanisms of long non-coding RNA small nucleolar RNA host gene 5 (SNHG5) during osteogenic differentiation remain unclear., Methods: We investigated the function of SNHG5, Yin Yang 1 (YY1), miR-212-3p and growth differentiation factor 5 (GDF5) in osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) in vitro and in vivo. Molecular mechanisms were clarified by chromatin immunoprecipitation assay and dual luciferase reporter assay., Results: We found SNHG5 expression was upregulated during osteogenesis of hBMSCs. Knockdown of SNHG5 in hBMSCs inhibited osteogenic differentiation while overexpression of SNHG5 promoted osteogenesis. Moreover, YY1 transcription factor directly bound to the promoter region of SNHG5 and regulated SNHG5 expression to promote osteogenesis. Dual luciferase reporter assay confirmed that SNHG5 acted as a miR-212-3p sponge and miR-212-3p directly targeted GDF5 and further activated Smad1/5/8 phosphorylation. miR-212-3p inhibited osteogenic differentiation, while GDF5 promoted osteogenic differentiation of hBMSCs. In addition, calvarial defect experiments showed knockdown of SNHG5 and GDF5 inhibited new bone formation in vivo., Conclusion: Our results demonstrated that the novel pathway YY1/SNHG5/miR-212-3p/GDF5/Smad regulates osteogenic differentiation of hBMSCs and may serve as a potential target for the treatment of bone loss., (© 2022. The Author(s).)

Kernel-based extreme learning machine (KELM), as a natural extension of ELM to kernel learning, has achieved outstanding performance in addressing various regression and classification problems. Compared with the basic ELM, KELM has a better generalization ability owing to no needs of the number of hidden nodes given beforehand and random projection mechanism. Since KELM is derived under the minimum mean square error (MMSE) criterion for the Gaussian assumption of noise, its performance may deteriorate under the non-Gaussian cases, seriously. To improve the robustness of KELM, this article proposes a mixture correntropy-based KELM (MC-KELM), which adopts the recently proposed maximum mixture correntropy criterion as the optimization criterion, instead of using the MMSE criterion. In addition, an online sequential version of MC-KELM (MCOS-KELM) is developed to deal with the case that the data arrive sequentially (one-by-one or chunk-by-chunk). Experimental results on regression and classification data sets are reported to validate the performance superiorities of the new methods.

Osteoclastogenesis in alveolar bone induced by compression stress triggers orthodontic tooth movement. Compression stress also stimulates angiogenesis, which is essential for osteoclastogenesis. However, the effects of osteoclastogenesis induced by compression on angiogenesis are poorly understood. In vivo, we found the markers of angiogenesis increased during orthodontic bone remodeling. In vitro, osteoclast-derived exosomes increased proliferation, migration, and tube formation of human umbilical vein endothelial cells (HUVECs), as well as expression of vascular endothelial growth factor and CD31. The promotive effects of exosomes derived from compressed osteoclasts were greater than those derived from osteoclasts without compression. Next, we analyzed changes in the microRNA transcriptome after compression stress and focused on microRNA146a-5p (miR-146a), which was significantly decreased by compression. Transfection of an inhibitor of miR-146a stimulated angiogenesis of HUVECs while miR-146a mimics repressed angiogenesis. Adiponectin (ADP) was confirmed to be a target of miR-146a by dual luciferase reporter assay. In HUVECs treated with exosomes, we detected increased ADP which promoted angiogenesis. Knockdown of ADP in HUVECs reduced the promotive effects of exosomes. Our results demonstrate that the decreased miR-146a observed in osteoclasts after compression promotes angiogenesis by targeting ADP, suggesting a novel method to interfere with bone remodeling induced by compression stress., (© 2021. Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Migration of cementoblasts to resorption lacunae is the foundation for repairing root resorption during orthodontic tooth movement. Previous studies reported that autophagy was activated by compression in periodontal ligament cells. The aim of this study was to investigate the migration of cementoblasts and determine whether autophagy is involved in the regulation of cementoblast migration under compressive force., Methods: Flow cytometry was employed to examine the apoptosis of murine cementoblasts (OCCM-30) at different compression times (0, 6, 12, and 24 hours) and magnitudes (0, 1.0, 1.5, and 2.0 g/cm 2 ). Cell proliferation was examined using the CCK-8 method. Wound healing migration assays and transwell migration assays were performed to compare the migration of cementoblasts. Chloroquine (CQ) and rapamycin were used to inhibit and activate autophagy, respectively. The level of autophagy was determined using western blotting and immunofluorescence staining. The expression of matrix metalloproteinases (MMPs) was assessed using quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot analysis, and enzyme-linked immunosorbent assay (ELISA)., Results: Cell apoptosis and proliferation did not significantly change in OCCM-30 cells under mechanical compression at magnitude of 1.5 g/cm 2 for 12 hours. However, the migration of cementoblasts was significantly inhibited after the application of compressive force. MMP2, MMP9, and MMP13 mRNA expression was decreased, and MMP9 and MMP13 protein expression and secretion level were also decreased. Further, autophagic activity was inhibited in cementoblasts under compressive force. Treatment with chloroquine reduced the cellular migration, and rapamycin partially relieved the inhibition of cementoblast migration induced by the compressive force. MMP9 and MMP13 mRNA expression, protein expression, and secretion levels showed a similar trend., Conclusion: Migration of OCCM-30 cells was inhibited under compressive force partially dependent on the inhibition of MMPs, which was mediated by downregulation of autophagy. The findings provide new insights into the role of autophagy in biological behaviors of cementoblasts under compressive force and a potential therapeutic strategy for reducing external root resorption., (© 2021 American Academy of Periodontology.)

As an effective and efficient discriminative learning method, broad learning system (BLS) has received increasing attention due to its outstanding performance in various regression and classification problems. However, the standard BLS is derived under the minimum mean square error (MMSE) criterion, which is, of course, not always a good choice due to its sensitivity to outliers. To enhance the robustness of BLS, we propose in this work to adopt the maximum correntropy criterion (MCC) to train the output weights, obtaining a correntropy-based BLS (C-BLS). Due to the inherent superiorities of MCC, the proposed C-BLS is expected to achieve excellent robustness to outliers while maintaining the original performance of the standard BLS in the Gaussian or noise-free environment. In addition, three alternative incremental learning algorithms, derived from a weighted regularized least-squares solution rather than pseudoinverse formula, for C-BLS are developed. With the incremental learning algorithms, the system can be updated quickly without the entire retraining process from the beginning when some new samples arrive or the network deems to be expanded. Experiments on various regression and classification data sets are reported to demonstrate the desirable performance of the new methods.

Objective: This study aimed to investigate how mechanical force affects the proliferation of human periodontal ligament stem cells (hPDLSCs)., Methods: CCK-8 assays and staining of ki67 were performed to evaluate hPDLSCs proliferation. qRT-PCR, ELISA, or Western blot analysis were used to measure the expression levels of interleukin (IL)-6, miR-31 host gene (MIR31HG), DNA methyltransferase 1 (DNMT1), and DNA methyltransferase 3B (DNMT3B). Dual-luciferase reporter assays and chromatin immunoprecipitation (ChIP) assays were conducted to determine whether MIR31HG was targeted by DNMT1 and DNMT3B. MassARRAY mass spectrometry was used to quantify DNA methylation levels of the MIR31HG promoter., Results: Mechanical force inhibited hPDLSCs proliferation with the downregulation of MIR31HG and upregulation of IL-6, DNMT1 and DNMT3B. Knockdown of MIR31HG suppressed hPDLSCs proliferation, and knockdown of DNMT1 or DNMT3B reversed mechanical force-induced downregulation of MIR31HG. Dual-luciferase and ChIP assays revealed DNMT1 and DNMT3B bound MIR31HG promoter in the region 1,015 bp upstream of the transcriptional start site. Treatment with 5'-aca-2'-deoxycytidine downregulated DNA methylation level in MIR31HG gene promoter, while mechanical force promoted the methylation of MIR31HG gene promoter., Conclusions: These findings elucidated how mechanical force affects proliferation via MIR31HG in hPDLSCs, providing clues for possible MIR31HG-based orthodontic therapeutic approaches., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.)

Introduction: Patients with severe periodontitis typically present with pathologic tooth migration. To improve esthetics and masticatory function, orthodontic treatment is required. Research on periodontal orthodontic treatment has been sparse, particularly from the microbial perspective. Hence, we analyzed the microbial and clinical changes in patients with well-controlled periodontitis in the early stage of orthodontic treatment., Methods: Ten patients with well-controlled periodontitis were asked to collect saliva before and 1 and 3 months after appliance placement (T0, T1, and T2, respectively) and underwent clinical examinations before and 1, 3, and 6 months after appliance placement (T0, T1, T2, and T3, respectively). The microbial community of saliva was analyzed by 16S rRNA gene sequencing. Gingival index, the plaque index, and the probing pocket depth were clinically assessed., Results: The plaque index significantly increased from T0 to T1 and decreased at T2 and T3. The probing pocket depth and gingival index increased slightly at T2, but not significantly, in both the high-risk site and low-risk site. The alpha and beta diversity increased at T1. The microbial community structure was similar at T0 and T2. The relative abundance of core genera and periodontal pathogens was stable during the initial 3 months of orthodontic treatment., Conclusions: The orthodontic appliance promoted plaque accumulation and altered the microbial community of patients with well-controlled periodontitis during the first month of orthodontic treatment. The microbial community returned to the basal composition at 3 months after appliance placement, and the periodontal inflammation during the 6-months orthodontic treatment was under control., (Copyright © 2021 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Orthodontic tooth movement is achieved by periodontal tissue remodeling triggered by mechanical force. It is essential to investigate the reaction of periodontal ligament stem cells (PDLSCs) for improving orthodontic therapeutic approaches. Autophagy is an endogenous defense mechanism to prevent mechanical damage of environmental change. Long non-coding RNAs (lncRNAs) are key regulators in gene regulation, but their roles are still largely uncharacterized in the reaction of PDLSCs during orthodontic tooth movement. In this study, we showed that autophagy was significantly induced in PDLSCs under compressive force, as revealed by the markers of autophagy, microtubule-associated protein light chain 3 (LC3) II/I and Beclin1, and the formation of autophagosomes. After the application of compressive force, lncRNA FER1L4 was strongly upregulated. Overexpression of FER1L4 increased the formation of autophagosome and autolysosomes in PDLSCs, while knockdown of FER1L4 reversed the autophagic activity induced by mechanical force. In mechanism, FER1L4 inhibited the phosphorylation of protein kinase B (AKT) and subsequently increased the nuclear translocation of forkhead box O3 (FOXO3) and thus mediated autophagic cascades under compressive strain. In mouse model, the expression of Lc3 as well as Fer1l4 was increased in the pressure side of periodontal ligament during tooth movement. These findings suggest a novel mechanism of autophagy regulation by lncRNA during periodontal tissue remodeling of orthodontic treatment., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Huang, Liu, Guo, Han, Yang, Zhao, Zheng, Jia and Li.)

Circular RNAs(circRNAs) are a large family of RNAs shaping covalently closed ring-like molecules and have become a hotspot with thousands of newly published studies. Stem cells are undifferentiated cells and have great potential in medical treatment due to their self-renewal ability and differentiation capacity. Abundant researches have unveiled that circRNAs have unique expression profile during the differentiation of stem cells and could serve as promising biomarkers of these cells. There are key circRNAs relevant to the differentiation, proliferation, and apoptosis of stem cells with certain mechanisms such as sponging miRNAs, interacting with proteins, and interfering mRNA translation. Moreover, several circRNAs have joined in the interplay between stem cells and lymphocytes. Our review will shed lights on the emerging roles of circRNAs in regulating the fate of diverse stem cells.

Purpose: Periodontitis is the leading cause of tooth loss. The role of long non-coding RNA (lncRNA) in periodontal inflammation remains unclear. The aim of this study was to investigate the role of lncRNA H19 in periodontitis and its possible regulation of autophagy in periodontitis., Material and Methods: Inflammation level was determined by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) in periodontal ligament cells (PDLCs). Western blotting, flow cytometric analysis, and immunofluorescence staining were used to detect the autophagy flux. Overexpression or knockdown of H19 was used to confirm its function. Ligature-induced periodontitis model in mice and periodontitis-affected human gingival tissue were used in vivo. RNA sequencing was performed to determine the differentially expressed genes., Results: Autophagy was significantly increased in PDLCs after inflammatory stimulation as well as in a ligature-induced periodontitis model in mice and periodontitis-affected human gingival tissue. During the inflammatory process, H19 expression was also significantly upregulated. Further, the levels of autophagic markers were significantly upregulated after overexpressing H19 in PDLCs, and the increased autophagic activity induced by inflammatory stimulation was reversed by H19 knockdown. RNA sequencing showed that the expression profiles of mRNAs were significantly altered after H19 overexpression, and the differentially expressed genes were enriched in the PI3K/AKT signaling pathway, which was confirmed by the decreased p-AKT protein expression in the H19 overexpression group., Conclusion: Periodontal inflammation activates autophagy flux, and H19 mediates the activation of autophagy via AKT pathway in periodontitis. This study expands our understanding of molecular regulation in periodontitis., Competing Interests: The authors report no conflicts of interest in this work., (© 2020 Guo et al.)

As the most important bone-resorbing cells, osteoclasts play fundamental roles in bone remodeling and skeletal health. Much effort has been focused on identifying the regulators of osteoclast metabolism. Noncoding RNAs (ncRNAs) reportedly regulate osteoclast formation, differentiation, survival, and bone-resorbing activity to participate in bone physiology and pathology. The present review intends to provide a general framework for how ncRNAs and their targets regulate osteoclast differentiation and the important events of osteoclastogenesis they are involved in, including osteoclast precursor generation, early differentiation, mononuclear osteoclast fusion, and multinucleated osteoclast function and survival. This framework is beneficial for understanding bone biology and for identifying the potential biomarkers or therapeutic targets of bone diseases. The review also summarizes the results of in vivo experiments and classic experiment methods for osteoclast-related researches., Competing Interests: All authors have no conflicts of interest., (Copyright © 2020 Yi Zhao et al.)

Osteoporosis is a prevalent metabolic bone disease characterized by low bone mineral density and degenerative disorders of bone tissues. Previous studies showed the abnormal osteogenic differentiation of endogenous bone marrow mesenchymal stem cells (BMSCs) contributes to the development of osteoporosis. However, the underlying mechanisms by which BMSCs undergo osteogenic differentiation remain largely unexplored. Recently, long non-coding RNAs have been discovered to play important roles in regulating BMSC osteogenesis. In this study, we first showed MIR22HG, which has been demonstrated to be involved in the progression of several cancer types, played an important role in regulating BMSC osteogenesis. We found the expression of MIR22HG was significantly decreased in mouse BMSCs from the osteoporotic mice and it was upregulated during the osteogenic differentiation of human BMSCs. Overexpression of MIR22HG in human BMSCs enhanced osteogenic differentiation, whereas MIR22HG knockdown inhibited osteogenic differentiation both in vitro and in vivo. Mechanistically, MIR22HG promoted osteogenic differentiation by downregulating phosphatase and tensin homolog (PTEN) and therefore activating AKT signaling. Moreover, we found MIR22HG overexpression promoted osteoclastogenesis of RAW264.7 cells, which indicated that MIR22HG played a significant role in bone metabolism and could be a therapeutic target for osteoporosis and other bone-related diseases.

Microstructured titanium surface implants, such as typical sandblasted and acid-etched (SLA) titanium implants, are widely used to promote bone apposition in prosthetic treatment by dental implants following tooth loss. Although there are multiple factors associated with the superior osseointegration of an SLA titanium surface, the molecular mechanisms of long noncoding RNAs (lncRNAs) are still unclear. In this study, we characterized smooth (SMO) and SLA surfaces, and compared the osteoinduction of these surfaces using human bone marrow-derived mesenchymal stem cells (hBMSCs) in vitro and implants in a rat model in vivo . Then, we used microarrays and bioinformatics analysis to investigate the differential expression profiles of mRNAs and lncRNAs on SMO and SLA titanium surfaces. An lncRNA-mRNA network was constructed, which showed an interaction between lncRNA HIF1A antisense RNA 1 (HIF1A-AS1) and vascular endothelial growth factor. We further found that knockdown of HIF1A-AS1 significantly decreased osteogenic differentiation of hBMSCs. This study screened SLA-induced lncRNAs using a systemic strategy and showed that lncRNA HIF1A-AS1 plays a role in promotion of new bone formation in the peri-implant area, providing a novel insight for future surface modifications of implants., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Both extracellular matrix (ECM) and stem cells contribute to the formation of bones. Accumulating evidence proved that the growth differentiation factor 5 (GDF5) plays a vital role in ECM osteogenesis regulation; the use of human periodontal ligament stem cells (hPDLSCs) may contribute to alveolar bone regeneration. Moreover, long noncoding RNAs (lncRNA) serves as a regulator in the growing process of cellular organisms including bone formation. Previous efforts has led us to the discovery that the expression of growth arrest specific transcript 5 (GAS5) changed in the osteogenic differentiation of hPDLSCs. Moreover, the expression of GAS5, as it turns out, is correlated to GDF5. This study attempts to investigate the inner workings of GAS5 in its regulation of osteoblastic differentiation of hPDLSCs. Cell transfection, Alkaline phosphatase (ALP) staining, Alizarin red S (ARS) staining, qRT-PCR, immunofluorescence staining analysis and western blotting were employed in this study. It came to our notice that GAS5 and GDF5 expression increased during osteogenesis induction of hPDLSCs. Knocking down of GAS5 inhibited the osteogenic differentiation of hPDLSCs, whereas overexpressing GAS5 promoted these effects. Molecular mechanism study further demonstrated that overexpressing GAS5 bolsters GDF5 expression and boosts the phosphorylation of JNK and p38 in hPDLSCs, with opposite effects in GAS5 knockdown group. To sum up, long noncoding RNA GAS5 serves to regulate the osteogenic differentiation of PDLSCs via GDF5 and p38/JNK signaling pathway. Our findings expand the theoretical understanding of the osteogenesis mechanism in hPDLSCs, providing new insights into the treatment of bone defects., (Copyright © 2020 Yang, Han, Liu, Huang, Li, Jia, Zheng and Li.)

Background: Periodontal ligament stromal cells (PDLSCs) are ideal cell sources for periodontal tissue repair and regeneration, but little is known about what determines their osteogenic capacity. Long non-coding RNAs (lncRNAs) are important regulatory molecules at both transcriptional and post-transcriptional levels. However, their roles in the osteogenic differentiation of PDLSCs are still largely unknown., Methods: The expression of lncRNA Fer-1-like family member 4 (FER1L4) during the osteogenic differentiation of PDLSCs was detected by quantitative reverse transcription polymerase chain reaction. Overexpression or knockdown of FER1L4 was used to confirm its regulation of osteogenesis in PDLSCs. Alkaline phosphatase and Alizarin red S staining were used to detect mineral deposition. Dual luciferase reporter assays were used to analyze the binding of miR-874-3p to FER1L4 and vascular endothelial growth factor A (VEGFA). Bone regeneration in critical-sized calvarial defects was assessed in nude mice. New bone formation was analyzed by micro-CT, hematoxylin and eosin staining, Masson's trichrome staining, and immunohistochemical analyses., Results: FER1L4 levels increased gradually during consecutive osteogenic induction of PDLSCs. Overexpression of FER1L4 promoted the osteogenic differentiation of PDLSCs, as revealed by alkaline phosphatase activity, Alizarin red S staining, and the expression of osteogenic markers, whereas FER1L4 knockdown inhibited these processes. Subsequently, we identified a predicted binding site for miR-874-3p on FER1L4 and confirmed a direct interaction between them. Wild-type FER1L4 reporter activity was significantly inhibited by miR-874-3p, whereas mutant FER1L4 reporter was not affected. MiR-874-3p inhibited osteogenic differentiation and reversed the promotion of osteogenesis in PDLSCs by FER1L4. Moreover, miR-874-3p targeted VEGFA, a crucial gene in osteogenic differentiation, whereas FER1L4 upregulated the expression of VEGFA. In vivo, overexpression of FER1L4 led to more bone formation compared to the control group, as demonstrated by micro-CT and the histologic analyses., Conclusion: FER1L4 positively regulates the osteogenic differentiation of PDLSCs via miR-874-3p and VEGFA. Our study provides a promising target for enhancing the osteogenic potential of PDLSCs and periodontal regeneration.

Objective: Secondary alveolar bone grafting is an essential part in the treatment of alveolar cleft deformity. Autologous iliac bone is the most favorable grafting source. However, the factors regulating postoperative bone formation are unclear. Investigations are needed to found whether the alveolar bone niche and bone marrow mesenchymal stem cells (BMSCs) derived from the jaw bone (BMSCs-J) affected the osteogenesis of BMSCs from the ilium (BMSCs-I)., Materials and Methods: The effect of BMSCs-J on BMSCs-I was investigated using a co-culture model. The exosomes were purified by sequential centrifugation. The osteoblastic differentiation of BMSCs was analyzed in vitro and in vivo., Results: Co-culture with BMSCs-J increased the alkaline phosphatase (ALP) activity, Alizarin Red S (ARS) staining, and osteogenic gene expression in BMSCs-I. Transmission electron microscopy and nanoparticle tracking analysis verified the presence of exosomes in the culture supernatants of BMSCs. Exosomes secreted by BMSCs-J enhanced the ALP activity, ARS staining, osteogenic gene expression of BMSCs-I in vitro, and new bone formation in vivo. Blocking the secretion of exosomes using siRNA for Rab27a inhibited the effect of BMSCs-J., Conclusion: Exosomes played a role in the interaction between BMSCs-J and BMSCs-I, thereby leading to the enhanced osteogenic capacity of BMSCs-I and bone formation., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.)

Objective: The role of long non-coding ribonucleic acids (lncRNAs) during orthodontic tooth movement remains unclear. We explored the lncRNA landscape of periodontal ligament stem cells (PDLSCs) subjected to compressive force., Materials and Methods: PDLSCs were subjected to static compressive stress (2 g/cm2) for 12 hours. Total RNA was then extracted and sequenced to measure changes in lncRNA and messenger RNA (mRNA) expression levels. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the expression levels of certain lncRNAs. Differential expression analysis as well as Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were also performed., Results: In total, 90 lncRNAs and 519 mRNAs were differentially expressed in PDLSCs under compressive stress. Of the lncRNAs, 72 were upregulated and 18 downregulated. The levels of eight lncRNAs of interest (FER1L4, HIF1A-AS2, MIAT, NEAT1, ADAMTS9-AS2, LUCAT1, MIR31HG, and DHFRP1) were measured via qRT-PCR, and the results were found to be consistent with those of RNA sequencing. GO and KEGG pathway analyses showed that a wide range of biological functions were expressed during compressive loading; most differentially expressed genes were involved in extracellular matrix organization, collagen fibril organization, and the cellular response to hypoxia., Conclusions: The lncRNA expression profile was significantly altered in PDLSCs subjected to compressive stress. These findings expand our understanding of molecular regulation in the mechanoresponse of PDLSCs., (© The Author(s) 2018. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

How to design a powerful classifier with strong generalization capability is still an active topic in the brain computer interface (BCI) researches. In this paper, we propose a new classifier, which has the same structure of the recently proposed broad learning system (BLS), but the l 2 norm based optimization model in BLS is replaced by a mixed-nrom based one. To optimize the proposed model efficiently, the augmented Lagrange multiplier (ALM) method is utilized. The most attractive feature of the proposed classifier is that it has the potential to maintain good performance in various noise environments, by flexibly setting the value of mixed parameter. Thus, compared with the standard BLS, as well as many existing classifiers, the proposed one is expected to be a more reasonable choice for classifying electroencephalography (EEG) signals, which are usually polluted by various artifacts. The experiments on two publicly available data sets are presented to confirm the desirable performance of the new method.

Bone grafting on defects caused by trauma or tumor stimulates bone regeneration, a complex process requiring highly orchestrated cell-signal interactions. Bone vascular growth is coupled with osteogenesis, but less is known about the interplay between angiogenesis and osteogenesis. Understanding this relationship is relevant to improved bone regeneration. Here, tricalcium phosphate (TCP) scaffolds doped with varying concentration of cobalt (Co-TCP) were designed to investigate the dosage effect of vascularization on bone formation. The surface structure, phase composition, mechanical features, and chemical composition were investigated. Co doping improved the mechanical properties of TCP. Co-TCP, particularly 2% and 5% Co-TCP, boosted cell viability of bone marrow stromal cells (BMSCs). The 2% Co-TCP promoted alkaline phosphatase activity, matrix mineralization, and expression of osteogenic genes in BMSCs in vitro. However, excessive Co doping decreased TCP-induced osteogenesis. Meanwhile, Co-TCP dose-dependently favored the growth and migration of human umbilical vein endothelial cells (HUVECs), and the expression of vascular endothelial growth factor (VEGF). The 2% Co-TCP significantly shrank the defect area in rat alveolar bone compared with TCP. Smaller bone volume and more abundant blood vessels were observed for 5% Co-TCP compared with 2% Co-TCP. The CD31 immunostaining in the 5% Co-TCP group was more intense than the other two groups, indicating of the increment of endothelium cells. Besides, 5% Co-TCP led to mild inflammatory response in bone defect area. Overall, TCP doped appropriately with Co has positive effect on osteogenesis, while excessive Co suppressed osteoblast differentiation and bone formation. These data indicate that vascularization within a proper range promotes osteogenesis, which may be a design consideration for bone grafts., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The characteristics of titanium (Ti) have been shown to influence dental implant fixation. Treatment of surfaces using the sandblasted, large-grit, acid-etched (SLA) method is widely used to provide effective osseointegration. However, the DNA methylation-associated mechanism by which SLA surface treatment affects osseointegration of human bone marrow mesenchymal stem cells (hBMSCs) remains elusive. Genome-wide methylation profiling of hBMSCs on SLA-treated and machined smooth Ti was performed using Illumina Infinium Methylation EPIC BeadChip at day 7 of osteogenic induction. In total, 2,846 CpG sites were differentially methylated in the SLA group compared with the machined group. Of these sites, 1,651 (covering 1,066 genes) were significantly hypermethylated and 1,195 (covering 775 genes) were significantly hypomethylated. Thirty significant enrichment pathways were observed, with Wnt signaling being the most significant. mRNA expression was identified by microarray and combined with DNA-methylation profiles. Thirty-seven genes displayed negative association between mRNA expression and DNA-methylation level, with the osteogenesis-related genes insulin-like growth factor 2 (IGF2) and carboxypeptidase X, M14 Family Member 2 (CPXM2) showing significant up-regulation and down-regulation, respectively. In summary, our results demonstrate differences between SLA-treated and machined surfaces in their effects on genome-wide DNA methylation and enrichment of osteogenic pathways in hBMSCs. We provide novel insights into genes and pathways affected by SLA treatment in hBMSCs at the molecular level., (© 2019 Eur J Oral Sci.)

Objectives: To investigate the long noncoding RNA (lncRNA) expression profile of cementoblasts under compressive force., Materials and Methods: Mouse cementoblasts were exposed to compression (1.5 g/cm 2 ) for 8 hours. RNA sequencing (RNA-seq) was performed to compare the transcriptomes of the compressed and control cells. Quantitative real-time polymerase chain reaction ( qRT-PCR) was used to validate five of the differentially expressed lncRNAs of interest. Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were also performed., Results: A total of 70 lncRNAs and 521 mRNAs were differentially regulated in cementoblasts subjected to compressive loading. Among the differentially expressed lncRNAs, 57 were upregulated and 13 downregulated. The expression levels of the five selected lncRNAs (Prkcz2, Hklos, Trp53cor1, Gdap10, and Ak312-ps) were validated by qRT-PCR and consistent with the RNA-seq results. GO functional annotation demonstrated upregulation of genes associated with cellular response to hypoxia and apoptotic processes during compressive loading. KEGG analysis identified the crucial pathways involving the hypoxia-inducing factor-1α, forkhead box O, and mammalian target of rapamycin signaling pathways., Conclusions: Mechanical compression changes the lncRNA expression profile of cementoblasts, providing important references for further investigation into the role and regulation of lncRNAs in compressed cementoblasts and root resorption during orthodontic treatment.

Circular RNAs (circRNAs), which are produced by back-splicing events in genes, have emerged as factors in gene regulation and normal cellular homeostasis. They play an important role not only in normal development of tissues and organs, but also in disease pathogenesis and cell differentiation. However, the role of circRNAs in bone marrow stem cells (BMSCs) undergoing osteoblast differentiation remains largely unknown. We performed microarray analysis to determine the expression profiles of circRNAs during osteoblast differentiation. In total, 3938 circRNAs were upregulated and 1505 were downregulated in BMSCs at day 7 (D7) compared with day 0 (D0). About 95% of the differentially expressed circRNAs were derived from protein coding genes, and functional annotation analysis showed that the parental genes of differentially expressed circRNAs were enriched in osteogenesis-associated terms. We also analyzed the microRNA (miRNA) transcriptome since circRNAs have been suggested to interact with miRNAs. We then selected the circRNAs that were negatively correlated with miRNAs and possessed miRNA response elements to construct a circRNA-miRNA interaction network. Analysis of the hub nodes in the networks showed that the top five nodes were miRNAs. Some circRNAs were linked to miRNAs with osteogenic roles, indicating that these circRNAs potentially function in osteogenic differentiation of BMSCs. Moreover, we validated the expression of one hub miRNA, miR-199b-5p, and its linked circIGSF11. Silencing of circIGSF11 promoted osteoblast differentiation and increased the expression of miR-199b-5p. Our study suggests that circRNA-miRNA interaction actively contributes to the osteogenic differentiation of human BMSCs, suggesting potential avenues for further study.

Although periodontal diseases during fixed appliance treatment are a common issue, few studies have focused on the clinical and microbial factors associated with orthodontic appliances. Hence, we investigated changes in the subgingival microbial community and their association with periodontal changes at the early stage of fixed appliance treatment. Subgingival plaques from ten female patients with fixed appliances were obtained at three time points: before, 1 month and 3 months after the placement of the brackets (T0, T1 and T2). The 16S rRNA gene sequencing was used to analyze the microbial community of the subgingival plaque. The Plaque Index (PI) and Gingival Bleeding Index (GBI) were also recorded. The GBI significantly increased at T2, and the PI showed a temporary increase without a significant difference. The alpha diversity indices were stable. However, the beta diversity was significantly higher at T2 compared to T0 and T1. The relative abundance of core microbiomes at the genus level was relatively stable. Four periodontal pathogens at the species level, including Prevotella intermedia (Pi), Campylobacer rectus (Cr), Fusobacterium nucleatum (Fn), and Treponema denticola (Td), increased without significant differences. The subgingival microbial community affected by fixed appliance treatment might cause transient mild gingival inflammation.

Objective: Ferritin, an iron-binding protein, is ubiquitous and highly conserved; it plays a crucial role in inflammation, which is the main symptom of periodontitis. Full-length cDNA library analyses have demonstrated abundant expression of ferritin in human periodontal ligament. The aims of the present study were to explore how ferritin is regulated by local inflammation, and to investigate its functions and mechanisms of action in the process of periodontitis., Methods: Human gingival tissues were collected from periodontitis patients and healthy individuals. Experimental periodontitis was induced by ligature of second molars in mice. The expression of ferritin light polypeptide (FTL) and ferritin heavy polypeptide (FTH) were assessed by immunohistochemistry. Meanwhile, after stimulating human periodontal ligament cells (HPDLCs) with P. gingivalis -lipopolysaccharide (LPS), interleukin (IL)-6, and tumor necrosis factor-α (TNF-α), the expression of FTH and FTL were measured. Then, IL-6 and IL-8 were measured after incubation with different concentrations of apoferritin (iron-free ferritin) and several intracellular signaling pathway inhibitors, or after knockdown of the transferrin receptor., Results: Both FTH and FTL were substantially higher in inflamed periodontal tissues than in healthy tissues. The location of the elevated expression correlated well with the extent of inflammatory infiltration. Moreover, expression of FTH and FTL were enhanced after stimulation with P. gingivalis -LPS, IL-6, TNF-α. Apoferritin induced the production of IL-6 and IL-8 in a dose-dependent manner partly through binding to the transferrin receptor and activating ERK/P38 signaling pathways in HPDLCs., Conclusions: Ferritin is up-regulated by inflammation and exhibits cytokine-like activity in HPDLCs inducing a signaling cascade that promotes expression of pro-inflammatory cytokines associated with periodontitis., (© 2019 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

Background: Periodontal ligament stem cells (PDLSCs) are considered as candidate cells for the regeneration of periodontal and alveolar bone tissues. Antisense to the cerebellar degeneration-related protein 1 transcript (CDR1as), which is a newly discovered circular RNA (circRNA), has been reported to act as an miR-7 sponge and to be involved in many biological processes. Here, we investigated the potential roles of CDR1as and miR-7 in the osteogenic differentiation of PDLSCs., Methods: The expression pattern of CDR1as and miR-7 in PDLSCs during osteogenesis was detected by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Then we overexpressed or knocked down CDR1as or miR-7 to confirm whether they were involved in the regulation of osteoblast differentiation in PDLSCs. Alkaline phosphatase (ALP) and alizarin red S (ARS) staining were used to detect the activity of osteoblasts and mineral deposition. Furthermore, a dual luciferase reporter assay was conducted to analyze the binding of miR-7 to growth differentiation factor (GDF)5. To further verify the role of CDR1as in osteoblast differentiation, we conducted animal experiments in vivo. New bone formation in specimens was analyzed by microcomputed tomography (micro-CT), hematoxylin and eosin staining, and immunofluorescence staining., Results: We observed that CDR1as was significantly upregulated during the osteogenic differentiation, whereas miR-7 was significantly downregulated. Moreover, knockdown of CDR1as and overexpression of miR-7 inhibited the ALP activity, ARS staining, and expression of osteogenic genes. Overexpression of miR-7 significantly reduced the activity of luciferase reporter vectors containing the wild-type, but not the mutant, 3' untranslated region (UTR) sequence of GDF5. Furthermore, knockdown of GDF5 partially reversed the effects of miR-7 inhibitor on osteoblast differentiation. Downregulation of CDR1as or GDF5 subsequently inhibited phosphorylation of Smad1/5/8 and p38 mitogen-activated protein kinases (MAPK), while upregulation of miR-7 decreased the level of phosphorylated Smad1/5/8 and p38 MAPK. In vivo, CDR1as knockdown lead to less bone formation compared with the control group as revealed by micro-CT and the histological analysis., Conclusions: Our results demonstrated that CDR1as acts as a miR-7 inhibitor, triggering the upregulation of GDF5 and subsequent Smad1/5/8 and p38 MAPK phosphorylation to promote osteogenic differentiation of PDLSCs. This study provides a novel understanding of the mechanisms of osteogenic differentiation, and suggests a potential method for promoting bone formation.

Titanium (Ti) implants are widely used in the clinic as bone substitutes and dental implants, but further improvements are needed to obtain high osteogenic ability and consequent osseointegration. Knockdown of long noncoding RNA MIR31HG promotes osteogenic differentiation and bone formation. In this study, we fabricated a Ti surface functionalized with siRNA targeting MIR31HG (siMIR31HG) and accelerated osteogenesis of bone marrow mesenchymal stem cells (BMSCs). Chitosan/siRNA complex was loaded onto the thermal alkali-treated Ti surface to fabricate the siMIR31HG-functionalized Ti surface. The surface morphology, siRNA loading and release efficiency, and transfection efficacy were investigated, and the biological effects, such as cell proliferation, cell morphology, and osteogenic activity, were determined. The results showed that the siMIR31HG-functionalized Ti implant generated an ∼50% knockdown of MIR31HG, with no apparent cytotoxicity, which consequently enhanced osteogenic differentiation of BMSCs, as indicated by the increase of ALP production, extracellular matrix mineralization, osteogenic gene expression, and ectopic bone formation in vivo. The siMIR31HG biofunctionalization can be used to obtain better osseointegration of Ti implant in the clinic.

Background: Long noncoding RNAs (lncRNAs) are regulatory molecules that participate in biological processes such as stem cell differentiation. Periodontal ligament stem cells (PDLSCs) exhibit great potential for the regeneration of periodontal tissue and the formation of new bone. However, although several lncRNAs have been found to be involved in the osteogenic differentiation of PDLSCs, the temporal transcriptomic landscapes of mRNAs and lncRNAs need to be mapped to obtain a complete picture of osteoblast differentiation. In this study, we aimed to characterize the time-course expression patterns of lncRNAs during the osteogenic differentiation of PDLSCs and to identify the lncRNAs that are related to osteoblastic differentiation., Methods: We cultured PDLSCs in an osteogenic medium for 3, 7, or 14 days. We then used RNA sequencing (RNA-seq) to analyze the expression of the coding and non-coding transcripts in the PDLSCs during osteogenic differentiation. We also utilized short time-series expression miner (STEM) to describe the temporal patterns of the mRNAs and lncRNAs. We then performed Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses to assess the biological relevance of genes in each profile, and used quantitative real-time PCR (qRT-PCR) to validate the differentially expressed mRNAs and lncRNAs that were associated with osteoblast differentiation. Lastly, we performed a knock down of two lncRNAs, MEG8, and MIR22HG, and evaluated the expression of osteogenic markers., Results: When PDLSCs were differentiated to osteoblasts, mRNAs associated with bone remodeling, cell differentiation, and cell apoptosis were upregulated while genes associated with cell proliferation were downregulated. lncRNAs showed stage-specific expression, and more than 200 lncRNAs were differentially expressed between the undifferentiated and osteogenically differentiated PDLSCs. Using STEM, we identified 25 temporal gene expression profiles, among which 14 mRNA and eight lncRNA profiles were statistically significant. We found that genes in pattern 12 were associated with osteoblast differentiation. The expression patterns of osteogenic mRNAs (COL6A1, VCAN, RRBP1, and CREB3L1) and lncRNAs (MEG8 and MIR22HG) were consistent between the qRT-PCR and RNA-seq results. Moreover, the knockdown of MEG8 and MIR22HG significantly decreased the expression of osteogenic markers (runt-related transcription factor 2 and osteocalcin)., Discussion: During the osteogenic differentiation of PDLSCs, both mRNAs and lncRNAs showed stage-specific expression. lncRNAs MEG8 and MIR22HG showed a high correlation with osteoblastogenesis. Our results can be used to gain a more comprehensive understanding of the molecular events regulating osteoblast differentiation and the identification of functional lncRNAs in PDLSCs., Competing Interests: The authors declare that they have no competing interests.

Background: The mammalian target of rapamycin (mTOR) pathway plays a significant role in osteogenic differentiation and bone maintenance. As the only known endogenous inhibitor of mTOR function, DEP domain containing mTOR interacting protein (DEPTOR) is potentially involved in stem cell differentiation, although the pathophysiological significance and its molecular mechanisms remain unclear. The present study aimed to elucidate the effects of DEPTOR on the progress of osteoporosis and investigate the underlying molecular mechanisms of osteogenic regulation., Methods: An ovariectomy mouse model with decreased bone formation and osteogenic induction with bone marrow mesenchymal stem cells (BMSCs) were used to investigate the relationship between DEPTOR and osteogenic events. A loss-of-function investigation was then performed to explore the role of DEPTOR in the osteogenic differentiation of BMSCs both in vitro and in vivo. Finally, long noncoding RNA (lncRNA) and mRNA sequences were investigated to reveal the underlying mechanisms of DEPTOR in osteogenic regulation. RNA interference, western blotting, and chromatin immunoprecipitation assays were performed for further mechanistic determination., Results: The results indicated that DEPTOR contributes to the progress of osteoporosis, and higher expression of Deptor was observed in osteoporotic bones. The expression of DEPTOR was reduced during the osteogenic differentiation of BMSCs, and knockdown of DEPTOR promoted BMSC osteogenesis in vitro and in vivo. lncRNA and mRNA sequences indicated that knockdown of DEPTOR upregulated the expression of maternally expressed 3 (nonprotein coding) (MEG3), which subsequently activated bone morphogenetic protein 4 (BMP4) signaling. Furthermore, DEPTOR could bind to a specific region (- 1000 bp ~ 0) of the MEG3 promoter to regulate its transcription, and inhibition of MEG3 reduced BMP4 activation triggered by DEPTOR knockdown., Conclusions: Taken together, our study revealed a novel function of DEPTOR in osteogenic differentiation by inhibiting MEG3-mediated activation of BMP4 signaling, which suggested that DEPTOR could be a therapeutic target for bone loss diseases and skeletal tissue regeneration.

The relationship between mechanical force and alveolar bone remodeling is an important issue in orthodontics because tooth movement is dependent on the response of bone tissue to the mechanical force induced by the appliances used. Mechanical cyclical stretch (MCS), fluid shear stress (FSS), compression, and microgravity play different roles in the cell differentiation and proliferation involved in bone remodeling. However, the underlying mechanisms are unclear, particularly the molecular pathways regulated by non-coding RNAs (ncRNAs) that play essential roles in bone remodeling. Amongst the various ncRNAs, miRNAs act as post-transcriptional regulators that inhibit the expression of their target genes. miRNAs are considered key regulators of many biologic processes including bone remodeling. Here, we review the role of miRNAs in mechanical force-induced bone metabolism., (© 2018 The Author(s).)

Mesenchymal stem cells (MSCs) are an important population of multipotent stem cells that differentiate into multiple lineages and display great potential in bone regeneration and repair. Although the role of protein-coding genes in the osteogenic differentiation of MSCs has been extensively studied, the functions of noncoding RNAs in the osteogenic differentiation of MSCs are unclear. The recent application of next-generation sequencing to MSC transcriptomes has revealed that long noncoding RNAs (lncRNAs) are associated with the osteogenic differentiation of MSCs. LncRNAs are a class of non-coding transcripts of more than 200 nucleotides in length. Noncoding RNAs are thought to play a key role in osteoblast differentiation through various regulatory mechanisms including chromatin modification, transcription factor binding, competent endogenous mechanism, and other post-transcriptional mechanisms. Here, we review the roles of lncRNAs in the osteogenic differentiation of bone marrow- and adipose-derived stem cells and provide a theoretical foundation for future research.