Integrin αVß3 antagonist-c(RGDyk) peptide attenuates the progression of ossification of the posterior longitudinal ligament by inhibiting osteogenesis and angiogenesis.

BACKGROUND: Ossification of the posterior longitudinal ligament (OPLL), an emerging heterotopic ossification disease, causes spinal cord compression, resulting in motor and sensory dysfunction. The etiology of OPLL remains unclear but may involve integrin αVß3 regulating the process of osteogenesis and angiogenesis. In this study, we focused on the role of integrin αVß3 in OPLL and explored the underlying mechanism by which the c(RGDyk) peptide acts as a potent and selective integrin αVß3 inhibitor to inhibit osteogenesis and angiogenesis in OPLL. METHODS: OPLL or control ligament samples were collected in surgery. For OPLL samples, RNA-sequencing results revealed activation of the integrin family, particularly integrin αVß3. Integrin αVß3 expression was detected by qPCR, Western blotting, and immunohistochemical analysis. Fluorescence microscopy was used to observe the targeted inhibition of integrin αVß3 by the c(RGDyk) peptide on ligaments fibroblasts (LFs) derived from patients with OPLL and endothelial cells (ECs). The effect of c(RGDyk) peptide on the ossification of pathogenic LFs was detected using qPCR, Western blotting. Alkaline phosphatase staining or alizarin red staining were used to test the osteogenic capability. The effect of the c(RGDyk) peptide on angiogenesis was determined by EC migration and tube formation assays. The effects of the c(RGDyk) peptide on heterotopic bone formation were evaluated by micro-CT, histological, immunohistochemical, and immunofluorescence analysis in vivo. RESULTS: The results indicated that after being treated with c(RGDyk), the osteogenic differentiation of LFs was significantly decreased. Moreover, the c(RGDyk) peptide inhibited the migration of ECs and thus prevented the nutritional support required for osteogenesis. Furthermore, the c(RGDyk) peptide inhibited ectopic bone formation in mice. Mechanistic analysis revealed that c(RGDyk) peptide could inhibit osteogenesis and angiogenesis in OPLL by targeting integrin αVß3 and regulating the FAK/ERK pathway. CONCLUSIONS: Therefore, the integrin αVß3 appears to be an emerging therapeutic target for OPLL, and the c(RGDyk) peptide has dual inhibitory effects that may be valuable for the new therapeutic strategy of OPLL.

Engineered Macrophage Membrane-Coated Nanoparticles with Enhanced CCR2 Expression Promote Spinal Cord Injury Repair by Suppressing Neuroinflammation and Neuronal death.

Spinal cord injury (SCI) is a severe neurological disorder characterized by significant disability and limited treatment options. Mitigating the secondary inflammatory response following the initial injury is the primary focus of current research in the treatment of SCI. CCL2 (C─C motif chemokine ligand 2) serves as the primary regulator responsible for inflammatory chemotaxis of the majority of peripheral immune cells, blocking the CCL2-CCR2 (C─C chemokine receptor type 2) axis has shown considerable therapeutic potential for inflammatory diseases, including SCI. In this study, it presents a multifunctional biomimetic nanoplatform (CCR2-MM@PLGA/Cur) specifically designed to target the CCL2-CCR2 axis, which consisted of an engineered macrophage membrane (MM) coating with enhanced CCR2 expression and a PLGA (poly (lactic-co-glycolic acid)) nanoparticle that encapsulated therapeutic drugs. CCR2 overexpression on MM not only enhanced drug-targeted delivery to the injury site, but also attenuated macrophage infiltration, microglia pro-inflammatory polarization, and neuronal apoptosis by trapping CCL2. Consequently, it facilitated neural regeneration and motor function recovery in SCI mice, enabling a comprehensive treatment approach for SCI. The feasibility and efficacy of this platform are confirmed through a series of in vitro and in vivo assays, offering new insights and potential avenues for further exploration in the treatment of SCI.

Engineering Copper-Containing Nanoparticles-Loaded Silicene Nanosheets with Triple Enzyme Mimicry Activities and Photothermal Effect for Promoting Bacteria-Infected Wound Healing.

Skin wounds accompanied by bacterial infections threaten human health, and conventional antibiotic treatments are ineffective for drug-resistant bacterial infections and chronically infected wounds. The development of non-antibiotic-dependent therapeutics is highly desired but remains a challenging issue. Recently, 2D silicene nanosheets with considerable biocompatibility, biodegradability, and photothermal-conversion performance have received increasing attention in biomedical fields. Herein, copper-containing nanoparticles-loaded silicene (Cu2.8O@silicene-BSA) nanosheets with triple enzyme mimicry catalytic (peroxidase, catalase, and oxidase-like) activities and photothermal function are rationally designed and fabricated for efficient bacterial elimination, angiogenesis promotion, and accelerated wound healing. Cu2.8O@silicene-BSA nanosheets display excellent antibacterial activity through synergistic effects of reactive oxygen species generated from multiple catalytic reactions, intrinsic bactericidal activity of released Cu2+ ions, and photothermal effects, achieving high antibacterial efficiencies on methicillin-resistant Staphylococcus aureus (MRSA) of 99.1 ± 0.7% in vitro and 97.2 ± 1.6% in vivo. In addition, Cu2.8O@silicene-BSA nanosheets exhibit high biocompatibility for promoting human umbilical vein endothelial cell (HUVEC) proliferation and angiogenic differentiation. In vivo experiments reveal that Cu2.8O@silicene-BSA nanosheets with synergistic photothermal/chemodynamic therapeutics effectively accelerate MRSA-infected wound healing by eliminating bacteria, alleviating inflammation, boosting collagen deposition, and promoting angiogenesis. This research presents a promising strategy to engineer photothermal-assisted nanozyme catalysis for bacteria-invaded wound healing.

Exosomal miR-140-5p inhibits osteogenesis by targeting IGF1R and regulating the mTOR pathway in ossification of the posterior longitudinal ligament.

BACKGROUND: Ossification of the posterior longitudinal ligament (OPLL) is a disabling disease whose pathogenesis is still unclear, and there are no effective cures or prevention methods. Exosomal miRNA plays an important role in the osteogenesis of ectopic bone. Therefore, we focused on the downregulation of miR-140-5p in OPLL cell-derived exosomes to explore the mechanism by which exosomal miR-140-5p inhibits osteogenesis in OPLL. RESULTS: Exosomes were isolated by differential centrifugation and identified by transmission electron microscopy, nanoparticle tracking analysis, and exosomal markers. Exosomal RNA was extracted to perform miRNA sequencing and disclose the differentially expressed miRNAs, among which miR-140-5p was significantly downregulated. Confocal microscopy was used to trace the exosomal miR-140-5p delivered from OPLL cells to human mesenchymal stem cells (hMSCs). In vitro, we verified that exosomal miR-140-5p inhibited the osteoblast differentiation of hMSCs by targeting IGF1R and suppressing the phosphorylation of the IRS1/PI3K/Akt/mTOR pathway. In vivo, we verified that exosomal miR-140-5p inhibited ectopic bone formation in mice as assessed by micro-CT and immunohistochemistry. CONCLUSIONS: We found that exosomal miR-140-5p could inhibit the osteogenic differentiation of hMSCs by targeting IGF1R and regulating the mTOR pathway, prompting a further potential means of drug treatment and a possible target for molecular therapy of OPLL.

Vertucci's root canal configuration of 11,376 mandibular anteriors and its relationship with distolingual roots in mandibular first molars in a Cantonese population: a cone-beam computed tomography study.

BACKGROUND: Cone-beam computed tomography (CBCT) was used to study the root canal system of mandibular anteriors (MAs) in a Cantonese population and to evaluate the correlation between the complicated root canal configurations of mandibular lateral incisors (MLIs) and the presence of distolingual roots (DLRs) in mandibular first molars (MFMs). METHODS: A total of 11,376 mandibular anterior teeth were scanned by CBCT. Those whose images met the inclusion criteria were first analysed according to Vertucci's root canal configuration and then grouped based on gender, age, and side, and their effects on root canal morphology were analysed. Finally, statistical analysis was used to evaluate the correlation between the complicated root canal configurations of MLIs and the existence of DLRs in MFMs. All statistical analyses were performed by using SPSS 25.0 software. Quantitative data are presented as the mean ± standard deviation. Student's t tests were used to calculate statistical significance. P < 0.05 was considered statistically significant. RESULTS: In MAs in the Cantonese population, all mandibular central incisors (MCIs) and MLIs had one root, and 0.37% of mandibular canines (MCs) had two roots. The most common Vertucci's root canal configuration was Vertucci I followed by Vertucci III. A total of 30.91% of MLIs and approximately 8% of MCIs and MCs have complicated root canal configurations. There were no significant differences in the prevalence of DLRs in MFMs and the incidence of complicated root canal configurations of MLIs between males and females or between the right and left teeth. However, a significant difference was found in different age groups of root canal configurations in MLIs. Moreover, significant ipsilateral and contralateral correlations between MFMs with DLRs and MLIs with complicated root canal configurations were observed on both sides. CONCLUSION: In Cantonese population, the possibility of complicated root canal configuration in MLIs was higher, when DLR appeared in MFMs.

Classification and morphology of middle mesial canals of mandibular first molars in a southern Chinese subpopulation: a cone-beam computed tomographic study.

BACKGROUND: Cone-beam computed tomography (CBCT) was employed to study the morphology and curvature of middle mesial canals (MMCs) of mandibular first molars (MFMs). METHODS: CBCT scanning was performed on MFMs of 1100 patients. Patients' images that met the inclusion criteria were divided into group A (< 40 years old) and group B (≥ 40 years old) for further study. The images were used to study the incidence of MMCs at different ages, measure the curvature of MMCs in the mesiodistal and buccolingual directions using the Schneider method, and observe the anatomical morphology of the mesial root canal system. All statistical analyses were performed by using SPSS 21.0 software. Quantitative data were presented as mean ± standard deviation. Student's t-test was used to calculate the statistical significance. P < 0.05 was considered statistically significant. RESULTS: In 875 patients, 1750 MFM images met the inclusion criteria. Among these cases, 158 MFMs contained an MMC, yielding an incidence rate of 9.03%. The incidence rate of MMCs was 11.22% in group A and 6.61% in group B, and this difference was statistically significant (P < 0.05). The curvature in the mesiodistal direction was 29.39 ± 8.53° in group A and 26.06 ± 8.50° in group B, and this difference was also significant (P < 0.05). The curved regions in groups A and B were often located in the middle 1/3 of canal. No significant difference in the distance between MMC orifices and mesiobuccal canal orifices or mesiolingual canal orifices was noted (P > 0.05). The most common mesial root canal morphological type was type II (3-2) (53.80%). CONCLUSION: The incidence of MMCs in MFMs declined as age increased. The canal systems of MMCs were varied and complex, mainly exhibiting an obvious mesiodistal curve. CBCT is an outstanding method to help guide root canal therapy. *Yeqing Yang and Buling Wu have contribute equally to this article.

Diagnostic biomarker candidates for pulpitis revealed by bioinformatics analysis of merged microarray gene expression datasets.

BACKGROUND: Pulpitis is an inflammatory disease, the grade of which is classified according to the level of inflammation. Traditional methods of evaluating the status of dental pulp tissue in clinical practice have limitations. The rapid and accurate diagnosis of pulpitis is essential for determining the appropriate treatment. By integrating different datasets from the Gene Expression Omnibus (GEO) database, we analysed a merged expression matrix of pulpitis, aiming to identify biological pathways and diagnostic biomarkers of pulpitis. METHODS: By integrating two datasets (GSE77459 and GSE92681) in the GEO database using the sva and limma packages of R, differentially expressed genes (DEGs) of pulpitis were identified. Then, the DEGs were analysed to identify biological pathways of dental pulp inflammation with Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and Gene Set Enrichment Analysis (GSEA). Protein-protein interaction (PPI) networks and modules were constructed to identify hub genes with the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and Cytoscape. RESULTS: A total of 470 DEGs comprising 394 upregulated and 76 downregulated genes were found in pulpitis tissue. GO analysis revealed that the DEGs were enriched in biological processes related to inflammation, and the enriched pathways in the KEGG pathway analysis were cytokine-cytokine receptor interaction, chemokine signalling pathway and NF-κB signalling pathway. The GSEA results provided further functional annotations, including complement system, IL6/JAK/STAT3 signalling pathway and inflammatory response pathways. According to the degrees of nodes in the PPI network, 10 hub genes were identified, and 8 diagnostic biomarker candidates were screened: PTPRC, CD86, CCL2, IL6, TLR8, MMP9, CXCL8 and ICAM1. CONCLUSIONS: With bioinformatics analysis of merged datasets, biomarker candidates of pulpitis were screened and the findings may be as reference to develop a new method of pulpitis diagnosis.

2D silicene nanosheets-loaded coating for combating implant-associated infection.

Implant-associated infection (IAI) is an unsolved problem in orthopaedics. Current therapies, including antibiotics and surgical debridement, can lead severe clinical and financial burdens on patients. Therefore, there is an urgent need to reinforce the inherent antibacterial properties of implants. Recently, two-dimensional (2D) silicene nanosheets (SNs) have gained increasing attention in biomedical fields owing to their considerable biocompatibility, biodegradability and strong photothermal-conversion performance. Herein, a dual-functional photosensitive coating on a Ti substrate (denoted as TPSNs) was rationally fabricated for bacterial inhibition and osteogenesis promotion. For the first time, SNs were loaded onto the surface of implants. Hyperthermia generated by the SNs and polydopamine (PDA) coating under 808 nm laser irradiation achieved the in vitro anti-bacterial efficiency of 90.7 ± 2.4 % for S. aureus and 88.0 ± 5.8 % for E. coli, respectively. In addition, TPSNs exhibited promising biocompatibility for the promotion of BMSC (bone marrow mesenchymal stem cells) proliferation and spreading. The presence of silicon (Si) in TPSNs contributed to the improved osteogenic differentiation of BMSCs, elevating the expressions of RUNX2 and OCN. In animal experiments, the combination of TPSNs with photothermal therapy (PTT) achieved an anti-bacterial efficiency of 89.2 % ± 1.6 % against S. aureus. Furthermore, TPSNs significantly improved bone-implant osseointegration in vivo. Overall, the development of a dual-functional TPSNs coating provides a new strategy for combating IAI.

Engineering of M2 Macrophages-Derived Exosomes via Click Chemistry for Spinal Cord Injury Repair.

Spinal cord injury (SCI) is one of the most common causes of death and disability. The effective modulation of complicated microenvironment, regeneration of injured spinal cord tissue, and the functional recovery after SCI are still clinical challenges. Recently, macrophages-derived exosomes have shown great potential for various diseases due to their inflammation-targeting property. However, further modifications are needed to endow exosomes with the neural regenerative potential for SCI recovery. In the current study, a novel nanoagent (MEXI) is designed for SCI treatment by conjugating bioactive IKVAV peptides to the surface of M2 macrophages-derived exosomes via an easy and rapid click chemistry method. In vitro, MEXI inhibits the inflammation by reprograming macrophages and promotes neuronal differentiation of neural stem cells. In vivo, engineered exosomes target the injured site of the spinal cord after tail vein injection. Furthermore, histological analysis reveals that MEXI improves motor functional recovery of SCI mice by reducing infiltration of macrophages, downregulating pro-inflammatory factors, and improving the regeneration of injured nervous tissues. Taken together, this study provides strong evidence for the significance of MEXI in SCI recovery.

Combined photothermal and sonodynamic therapy using a 2D black phosphorus nanosheets loaded coating for efficient bacterial inhibition and bone-implant integration.

Surgical site infection (SSI) remains a major threat for implant failure in orthopedics. Herein, we report a dual-functional coating on Ti implants (named Ti/PDA/BP) with the integration of two-dimensional (2D) photo-sono sensitive black phosphorus nanosheets (BPNSs) and polydopamine (PDA) for efficient bacterial inhibition and bone-implant integration. For the first time, we employ BPNSs as generators of reactive radicals (ROS) under ultrasound (US) stimuli for implant associated infection. Additionally, the application of PDA improves the stability of BPNSs, the biocompatibility and photothermal performance of this hybrid coating. The as-prepared Ti/PDA/BP coating exhibits superior biocompatibility, bioactivity, photothermal and sonodynamic conversion abilities. Owing to the synergistic effect of hyperthermia and ·OH, Ti/PDA/BP damages the membrane and antioxidant system of Staphylococcus aureus, reaching a high antibacterial activity of 96.6% in vitro and 97.3% in vivo with rapid 10 min NIR irradiation and 20 min US treatment. In addition, we firstly unveil the significant effect of Ti/PDA/BP-based sonodynamic therapy (SDT) on bacterial membrane and oxidative stress at the transcriptome level. Moreover, the Ti/PDA/BP coating remarkably promotes osteogenesis in vitro and bone-implant osseointegration in vivo. Overall, development of Ti/PDA/BP bioactive coating provides a new strategy for combating the implant associated infection.

Remote ischemic preconditioning protects against spinal cord ischemia-reperfusion injury in mice by activating NMDAR/AMPK/PGC-1α/SIRT3 signaling.

BACKGROUND: To study the protective effects of delayed remote ischemic preconditioning (RIPC) against spinal cord ischemia-reperfusion injury (SCIRI) in mice and determine whether SIRT3 is involved in this protection and portrayed its upstream regulatory mechanisms. METHODS: In vivo, WT or SIRT3 global knockout (KO) mice were exposed to right upper and lower limbs RIPC or sham ischemia. After 24 h, the abdominal aorta was clamped for 20 min, then re-perfused for 3 days. The motor function of mice, number of Nissl bodies, apoptotic rate of neurons, and related indexes of oxidative stress in the spinal cord were measured to evaluate for neuroprotective effects. The expression and correlation of SIRT3 and NMDAR were detected by WB and immunofluorescence. In vitro, primary neurons were exacted and OGD/R was performed to simulate SCIRI in vivo. Neuronal damage was assessed by observing neuron morphology, detecting LDH release ratio, and flow cytometry to analyze the apoptosis. MnSOD and CAT enzyme activities, GSH and ROS level were also measured to assess neuronal antioxidant capacity. NMDAR-AMPK-PGC-1α signaling was detected by WB to portray upstream regulatory mechanisms of RIPC regulating SIRT3. RESULTS: Compared to the SCIRI mice without RIPC, mice with RIPC displayed improved motor function recovery, a reduced neuronal loss, and enhanced antioxidant capacity. To the contrary, the KO mice did not exhibit any effect of RIPC-induced neuroprotection. Similar results were observed in vitro. Further analyses with spinal cord tissues or primary neurons detected enhanced MnSOD and CAT activities, as well as increased GSH level but decreased MDA or ROS production in the RIPC + I/R mice or NMDA + OGD/R neurons. However, these changes were completely inhibited by the absence of SIRT3. Additionally, NMDAR-AMPK-PGC-1α signaling was activated to upregulate SIRT3 levels, which is essential for RIPC-mediated neuroprotection. CONCLUSIONS: RIPC enhances spinal cord ischemia tolerance in a SIRT3-dependent manner, and its induced elevated SIRT3 levels are mediated by the NMDAR-AMPK-PGC-1α signaling pathway. Combined therapy targeting SIRT3 is a promising direction for treating SCIRI.

M2 macrophage-derived exosome-encapsulated microneedles with mild photothermal therapy for accelerated diabetic wound healing.

Due to local overactive inflammatory response and impaired angiogenesis, current treatments for diabetic wounds remain unsatisfactory. M2 macrophage-derived exosomes (MEs) have shown considerable potential in biomedical applications, especially since they have anti-inflammatory properties that modulate macrophage phenotypes. However, exosome-based strategies still have limitations, such as short half-lives and instability. Herein, we develop a double-layer microneedle-based wound dressing system (MEs@PMN) by encapsulating MEs in the needle tips and polydopamine (PDA) nanoparticles in backing layer to simultaneously suppress inflammation and improve angiogenesis at the wound site. In vitro, released MEs increased macrophage polarization towards the M2 phenotype. In addition, mild heat (40 â€‹°C) generated by the photosensitive PMN backing layer contributed to improved angiogenesis. More importantly, MEs@PMN also showed promising effects in diabetic rats. The uncontrolled inflammatory response at the wound site was inhibited by MEs@PMN during a 14-day period; in addition, MEs and the photothermal effects produced by PMN provided a combined proangiogenic effect by improving the expression of CD31 and vWF. Collectively, this study provides a simple and efficient cell-free strategy for suppressing inflammation and promoting vascular regeneration to treat diabetic wounds.

A novel hypoxic lncRNA, HRL-SC, promotes the proliferation and migration of human dental pulp stem cells through the PI3K/AKT signaling pathway.

BACKGROUND: Human dental pulp stem cells (hDPSCs) are critical for pulp generation. hDPSCs proliferate faster under hypoxia, but the mechanism by which long noncoding RNA (lncRNA) regulates this process is not fully understood. METHODS: Novel lncRNAs were obtained by reanalysis of transcriptome datasets from RNA-Seq under hypoxia compared with normoxia, and a differential expression analysis of target genes was performed. Bioinformatics analyses, including gene ontology analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis and gene set enrichment analysis, were used to understand the function of key novel lncRNAs. hDPSCs were isolated from dental pulp tissue. EdU and scratch wound healing assays were used to detect the proliferation and migration of hDPSCs. qRT-PCR was used to detect changes in the RNA expression of selected genes. RNA fluorescence in situ hybridization, small interfering RNA, qRT-PCR and Western blot analysis were used to explore the function of key novel lncRNAs. RESULTS: We identified 496 novel lncRNAs in hDPSCs under hypoxia, including 45 differentially expressed novel lncRNAs. Of these, we focused on a key novel lncRNA, which we designated HRL-SC (hypoxia-responsive lncRNA in stem cells). Functional annotation revealed that HRL-SC was associated with hypoxic conditions and the PI3K/AKT signaling pathway. HRL-SC was mainly located in the cytoplasm of hDPSCs and had stable high expression under hypoxia. Knockdown of HRL-SC inhibited the proliferation and migration of hDPSCs and the expression levels of PI3K/AKT-related marker proteins. Furthermore, the AKT activator SC79 partially offset the inhibitory effect caused by the knockdown, indicating that HRL-SC promoted hDPSCs through the PI3K/AKT signaling pathway. CONCLUSIONS: Hypoxia-responsive lncRNA HRL-SC promotes the proliferation and migration of hDPSCs through the PI3K/AKT signaling pathway, and this understanding may facilitate the regenerative application of hDPSCs.

Pulp revascularization on an adult mandibular right second premolar: A case report.

BACKGROUND: Pulp revascularization has become a new method for the treatment of periapical diseases in young permanent teeth in recent years. Through root canal flushing and disinfection, avoiding mechanical preparation, guiding apical stem cells into the root canal and promoting the continuous development of tooth roots, it has achieved good clinical curative effects. But in adult patients with chronic periapical periodontitis with immature roots and open apices, apical barrier technology is often used to treat these teeth. CASE SUMMARY: Pulp revascularization of a 26-year-old patient's tooth was performed using cefaclor instead of minocycline and iRoot BP instead of mineral trioxide aggregate as intracanal medication. The case was followed up for 36 mo. Observations showed evidence of regression of clinical signs and symptoms, resolution of apical periodontitis and no discolouration of affected teeth. CONCLUSION: For adult patients with chronic periapical periodontitis with immature roots and open apices, pulp revascularisation showed favourable results in treating these teeth.

METTL3-Mediated lncSNHG7 m6A Modification in the Osteogenic/Odontogenic Differentiation of Human Dental Stem Cells.

Background: Human dental pulp stem cells (hDPSCs) play an important role in endodontic regeneration. N6-methyladenosine (m6A) is the most common RNA modification, and noncoding RNAs have also been demonstrated to have regulatory roles in the expression of m6A regulatory proteins. However, the study on m6A modification in hDPSCs has not yet been conducted. Methods: Single base site PCR (MazF) was used to detect the m6A modification site of lncSNHG7 before and after mineralization of hDPSCs to screen the target m6A modification protein, and bioinformatics analysis was used to analyze the related pathways rich in lncSNHG7. After knockdown and overexpression of lncSNHG7 and METTL3, the osteogenic/odontogenic ability was detected. After METTL3 knockdown, the m6A modification level and its expression of lncSNHG7 were detected by MazF, and their binding was confirmed. Finally, the effects of lncSNHG7 and METTL3 on the Wnt/ß-catenin pathway were detected. Results: MazF experiments revealed that lncSNHG7 had a m6A modification before and after mineralization of hDPSCs, and the occurrence site was 2081. METTL3 was most significantly upregulated after mineralization of hDPSCs. Knockdown/ overexpression of lncSNHG7 and METTL3 inhibited/promoted the osteogenic/odontogenic differentiation of hDPSCs. The m6A modification and expression of lncSNHG7 were both regulated by METTL3. Subsequently, lncSNHG7 and METTL3 were found to regulate the Wnt/ß-catenin signaling pathway. Conclusion: These results revealed that METTL3 can activate the Wnt/ß-catenin signaling pathway by regulating the m6A modification and expression of lncSNHG7 in hDPSCs to enhance the osteogenic/odontogenic differentiation of hDPSCs. Our study provides new insight into stem cell-based tissue engineering.

circRNA Expression Profile in Dental Pulp Stem Cells during Odontogenic Differentiation.

INTRODUCTION: Odontogenic differentiation of human dental pulp stem cells (hDPSCs) is a key step of pulp regeneration. Recent studies showed that circular RNAs (circRNAs) have many biological functions and that competing endogenous RNA (ceRNA) is their most common mechanism of action. However, the role of circRNAs in hDPSCs during odontogenesis is still unclear. METHODS: Isolated hDPSCs were cultured in essential and odontogenic medium. Total RNA was extracted after 14 days of culture, and then, microarray analysis was performed to measure the differential expressions of circRNAs. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was then performed to validate the microarray results. Based on microarray data from this study and available in the database, a ceRNA network was constructed to investigate the potential function of circRNAs during odontogenesis. In addition, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to investigate the potential correlation between signaling pathways and circRNAs. In addition, qRT-PCR and Western blot analysis were used to explore the function of hsa_circRNA_104101. RESULTS: We found 43 upregulated circRNAs and 144 downregulated circRNAs during the odontogenic differentiation process (fold change > 1.5 and <-1.5, respectively; P < 0.05). qRT-PCR results were in agreement with the microarray results. Bioinformatic analysis revealed that the Wnt signaling pathway and the TGF-ß signaling pathway, as well as the other pathways associated with odontogenic differentiation, were correlated to the differentially expressed circRNAs. hsa_circRNA_104101 was proved to promote the odontogenic differentiation of hDPSCs. CONCLUSION: This study reported 187 circRNAs that were differentially expressed in hDPSCs during odontogenic differentiation. Bioinformatic analysis of the expression data suggested that circRNA-miRNA-mRNA networks might act as a crucial mechanism for hDPSC odontogenic differentiation, providing a theoretical foundation for the study of pulp regeneration regulation by circRNAs.

Osteoblastic and anti-osteoclastic activities of strontium-substituted silicocarnotite ceramics: In vitro and in vivo studies.

Osteoporosis bone defect is a refractory orthopaedic disease which characterized by impaired bone quality and bone regeneration capacity. Current therapies, including antiosteoporosis drugs and artificial bone grafts, are not always satisfactory. Herein, a strontium-substituted calcium phosphate silicate bioactive ceramic (Sr-CPS) was fabricated. In the present study, the extracts of Sr-CPS were prepared for in vitro study and Sr-CPS scaffolds were used for in vivo study. The cytocompatibility, osteogenic and osteoclastogenic properties of Sr-CPS extracts were characterized in comparison to CPS. Molecular mechanisms were also evaluated by Western blot. Sr-CPS extracts were found to promote osteogenesis by upregulating Wnt/ß-catenin signal pathways and inhibit osteoclastogenesis through downregulating NF-κB signal pathway. In vivo, micro-CT, histological and histomorphometric observation were conducted after 8 weeks of implantation to evaluate the bone formation using calvarial defects model in ovariectomized rats. Compared with CPS, Sr-CPS significantly promoted critical sized ovariectomy (OVX) calvarial defects healing. Among all the samples, Sr-10 showed the best performance due to a perfect match of bone formation and scaffold degradation rates. Overall, the present study demonstrated that Sr-CPS ceramic can dually modulate both bone formation and resorption, which might be a promising candidate for the reconstruction of osteoporotic bone defect.

Magnoflorine Suppresses MAPK and NF-κB Signaling to Prevent Inflammatory Osteolysis Induced by Titanium Particles In Vivo and Osteoclastogenesis via RANKL In Vitro.

Wear particles that detach from the surface of prostheses induce excessive activation of osteoclast and immoderate release of inflammatory cytokines that lead to peri-implant osteolysis and aseptic loosening. In this work, we investigated whether magnoflorine, a quaternary aporphine alkaloid extracted from the Chinese herb Magnolia or Aristolochia, could effectively inhibit inflammatory calvarial osteolysis caused by titanium particles in mouse models, inflammatory response as well as osteoclastogenesis in vitro mediated via receptor activator of NF-κB ligand (RANKL). Micro-computed tomography and histological examination of mice treated with magnoflorine revealed fewer resorption pits, less osteoclasts formation and inflammatory cytokine expression. Moreover, in vitro differentiation of osteoclasts and bone resorption as well as titanium particle-induced inflammatory response were dose-dependently inhibited by magnoflorine. These were accompanied by reduced transcription of osteoclast-specific genes encoding tartrate-resistant acid phosphatase (TRAP), V-ATPase d2, c-Fos, cathepsin K, nuclear factor of activated T cells (NFAT) c1, and calcitonin receptor (CTR). Further research on mechanism showed that the inhibition of phosphorylation of TAK1 and subsequent activation of MAPK and NF-κB signaling pathways were found to mediate the suppressive effects of magnoflorine. Collectively, these results suggested that magnoflorine treatment could effectively prevent peri-implant osteolysis due to wear debris as well as other diseases caused by chronic inflammation and excessive osteoclast activation.

Negative Pressure Wound Therapy Versus Closed Suction Irrigation System in the Treatment of Deep Surgical Site Infection After Lumbar Surgery.

OBJECTIVE: We compared the efficacy of a closed suction irrigation system (CSIS) and negative pressure wound therapy (NPWT) for deep surgical site infection (SSI) after lumbar surgery with instrumentation. METHODS: We included 31 patients (NPWT group, n =16; CSIS group, n = 15) with deep SSIs after lumbar surgery with instrumentation from 2007 to 2017. The medical records were reviewed and patient characteristics, laboratory results, infection details, and treatment interventions were recorded. The Japanese Orthopaedic Association score and Oswestry disability index were used to assess pain and functional outcomes preoperatively and 3 and 12 months postoperatively. The cost of SSIs were compared between the NPWT and CSIS groups. RESULTS: No significant differences were found in the baseline characteristic data between the NPWT and CSIS groups. Implants were retained in all patients in the CSIS group, but required removal from 2 patients with late infections in the NPWT group. The average hospital stay was 36.8 ± 10.5 days and 33.4 ± 18.9 days in the NPWT and CSIS groups, respectively. The cost was greater in the NPWT group than in the CSIS group. Both NPWT and CSIS significantly reduced the Oswestry disability index and improved the Japanese Orthopaedic Association scores, but no significant difference was found between the 2 groups. CONCLUSIONS: Our results have shown that both NPWT and CSIS are efficient techniques for the management of deep SSI after lumbar surgery with instrumentation. CSIS was more economical and the NPWT system was portable and easier for postoperative nursing care.

Measurement of the nerve root of the lower lumbar region using digital images.

The purpose of this study was to evaluate the relationship between the nerve root of lower lumbar and the surrounding structures using three-dimensional computed tomography (3D CT).Twenty-three consecutive patients with thoracolumbar fractures without obvious radiological degeneration were retrospectively studied at the spinal surgery department of the hospital. The parameters of the relationship between the nerve root of the lower lumbar and the surrounding structures were measured using 3D CT in the work station of the picture archiving and communication system.The size of the dorsal root ganglion (DRG) of the L4 was 5.5 ±â€Š0.4 mm on the right side and 5.8 ±â€Š0.3 mm on the left side. The size of the DRG of the L5 was 6.1 ±â€Š0.5 mm on the right side and 5.7 ±â€Š0.4 mm on the left side. The value of the preganglionic nerve root of the L4 was 11.2 ±â€Š0.6 mm on the right side and 12.3 ±â€Š0.8 mm on the left side, and the value of the preganglionic nerve root of the L5 was 15.1 ±â€Š1.1 mm on the right side and 14.9 ±â€Š0.9 mm on the left side.Using 3D CT imaging constructed in the picture archiving and communication system is a practical and convenient method for evaluating the relationship between the nerve root and the surrounding structures in the routine clinical work of a spinal surgeon. The data obtained through 3D CT imaging will be helpful for surgeons, allowing them to become more familiar with correlating anatomical knowledge of individual patient.