Periodontal ligament-associated protein-1 knockout mice regulate the differentiation of osteoclasts and osteoblasts through TGF-ß1/Smad signaling pathway.

It has been known that periodontal ligament-associated protein-1 (PLAP-1/Asporin) not only inhibits cartilage formation in osteoarthritis, but it also influences the healing of skull defect. However, the effect and mechanism of PLAP-1/Asporin on the mutual regulation of osteoclasts and osteoblasts in periodontitis are not clear. In this study, we utilized a PLAP-1/Asporin gene knockout (KO) mouse model to research this unknown issue. We cultured mouse bone marrow mesenchymal stem cells with Porphyromonas gingivalis lipopolysaccharide (P.g. LPS) for osteogenic induction in vitro. The molecular mechanism of PLAP-1/Asporin in the regulation of osteoblasts was detected by immunoprecipitation, immunofluorescence, and inhibitors of signaling pathways. The results showed that the KO of PLAP-1/Asporin promoted osteogenic differentiation through transforming growth factor beta 1 (TGF-ß1)/Smad3 in inflammatory environments. We further found the KO of PLAP-1/Asporin inhibited osteoclast differentiation and promoted osteogenic differentiation through the TGF-ß1/Smad signaling pathway in an inflammatory coculture system. The experimental periodontitis model was established by silk ligation and the alveolar bone formation in PLAP-1/Asporin KO mice was promoted through TGF-ß1/Smad3 signaling pathway. The subcutaneous osteogenesis model in nude mice also confirmed that the KO of PLAP-1/Asporin promoted bone formation by the histochemical staining. In conclusion, PLAP-1/Asporin regulated the differentiation of osteoclasts and osteoblasts through TGF-ß1/Smad signaling pathway. The results of this study lay a theoretical foundation for the further study of the pathological mechanism underlying alveolar bone resorption, and the prevention and treatment of periodontitis.

4-Octyl itaconate promotes alveolar ridge preservation following tooth extraction.

The search for medications that can effectively reduce alveolar bone loss following tooth extraction is of great interest. This study aimed to observe the roles of 4-octyl itaconate (4-OI) in RANKL-induced osteoclastogenesis of bone marrow macrophages (BMMs) in vitro. Mandibular second molars were extracted to evaluate whether 4-OI could alleviate alveolar bone loss. 4-OI inhibited RANKL-induced osteoclastogenesis and promoted Nrf2 expression in bone marrow macrophages in vitro. Positive Nrf2 expressions were observed in inflammatory cells and osteoclasts in vivo. Treatment with 4-octyl itaconate increased Nrf2 expression, resulting in reduced inflammatory infiltration and osteoclastic activity after tooth extraction. Furthermore, increased expression of OCN and enhanced-alveolar bone healing of extraction socket were observed in the 4-OI group compared to the control group. Our results suggested that 4-OI could serve as a promising pharmacologic candidate for alveolar ridge preservation by alleviating alveolar bone loss following tooth extraction in rats.

DLK1 regulates periodontal inflammation by inhibiting NF-κB p65 and JNK signaling pathways.

The roles and molecular mechanisms of Delta-like 1 (DLK1) in periodontitis remain largely unknown. Here, we investigated the expression of DLK1 and NF-κB p65 in Porphyromonas gingivalis (Pg.)-induced periodontitis in vivo. Periodontal inflammation and alveolar bone resorption were analyzed using western blotting, micro-computed tomography, TRAP staining, immunohistochemistry, and immunofluorescence. Raw246.7 cells were stimulated with 1 µg/ml Porphyromonas gingivalis lipopolysaccharide (Pg.LPS) to assess DLK1 expression in vitro. DLK1 overexpression was achieved, and transfection efficiency was confirmed using western blotting and immunofluorescence. The NF-κB and MAPK pathways were activated by treating cells with 1 µg/ml Pg.LPS to explore related mechanisms. Compared with normal tissues, both DLK1 and NF-κB p65 expression increased in periodontitis gingival tissues. DLK1-positive expression was observed in inflammatory infiltrating cells and osteoclasts in the marginal lacunae of the alveolar bone. DLK1 expression in CD68-positive macrophages was detected by immunofluorescence. However, DLK1 expression in Raw246.7 cells decreased after Pg.LPS stimulation and during osteoclast differentiation. DLK1 levels negatively correlated with TNF-α, IL-1ß, and NFATC1. Increased DLK1 in Raw246.7 cells further inhibited COX2 and iNOS expressions. Mechanistically, DLK1 overexpression down-regulated NF-κB p65 and JNK levels. In summary, these findings suggest that DLK1 overexpression inhibits periodontal inflammation through the NF-κB p65 and JNK pathways. Interventions targeting increased DLK1 levels may have therapeutic implications for periodontitis.

Intervention with extracellular matrix metalloproteinase inducer in osteoclasts attenuates periodontitis-induced bone resorption.

Extracellular matrix metalloproteinase inducer (EMMPRIN) plays critical roles in the regulation of inflammation and bone metabolism. The roles of EMMPRIN signaling in osteoclasts are worthy of deep study. The present study aimed to investigate bone resorption in periodontitis through the intervention of EMMPRIN signaling. The distribution of EMMPRIN in human periodontitis was observed. RANKL-induced osteoclast differentiation of mouse bone marrow-derived macrophages (BMMs) were treated with EMMPRIN inhibitor in vitro. Rats with ligation-induced periodontitis were treated with EMMPRIN inhibitor and harvested for microcomputed tomography scanning, histologic observation, immunohistochemistry, and double immunofluorescence analysis. Positive expressions of EMMPRIN could be found in the CD68+-infiltrating cells. Downregulated EMMPRIN restrained osteoclast differentiation of BMMs in vitro, which also inhibited MMP-9 expression (*P < 0.05). In vivo, EMMPRIN inhibitor restrained ligation-induced bone resorption by decreasing tartrate-resistant acid phosphatase-positive osteoclasts. Both EMMPRIN-positive and MMP-9-positive osteoclasts were less common in the EMMPRIN inhibitor groups than in the control groups. Intervention of EMMPRIN signaling in osteoclasts could probably provide a potential therapeutic target for attenuating ligation-induced bone resorption.

Denervation delays initial bone healing of rat tooth extraction socket.

Functions of nerves on bone has been a subject of intense research. The aim of this study is to observe initial bone healing of rat tooth extraction socket after inferior alveolar nerve transection. The bilateral mandible second molars of eighteen Wistar rats were extracted in the study. The rats also suffered from right inferior alveolar nerve transection simultaneously (D + E group), only extraction as control (E group). One, two and four weeks after extraction, the mandibles were taken out for histological observation, TRAP staining, immunofluorescence, immunohistochemistry and micro-computed tomography (Micro-CT). Mouse bone marrow derived macrophages (BMMs) were cultured in vitro. Expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) were detected in vivo and vitro. The alveolar sockets had been filled to a large extent with new bone at 4 weeks, but BV/TV and BMD decreased in the D + E group. Accordingly, Expressions of osteocalcin (OCN) and osteopontin (OPN) were down-regulated in the D + E group. Denervation increased TRAP-positive osteoclasts and decreased expressions of Nrf2 at 2 weeks after extraction. Decreased Nrf2 promoted osteoclast differentiation of BMMs in vitro. Denervation delays initial bone healing of rat tooth extraction socket. Osteoclast activation induced by decreased Nrf2 might participated in the process.

Shikonin promotes rat periodontal bone defect repair and osteogenic differentiation of BMSCs by p38 MAPK pathway.

In recent years, the treatment of periodontal bone defect has been a major challenge. Cell-based bone tissue engineering provides an advanced way for bone regeneration. Bone formation hinges on the potential of osteogenesis in bone marrow stromal cells (BMSCs). Shikonin (SHI), an active principle of Radix Lithospermi, has shown a striking role to mitigate osteoporosis of ovariectomized mice, whereas its effects on periodontal bone defect are vague. Herein, we explored the impact of SHI on osteogenic differentiation of BMSCs in vitro and further analyzed the potential mechanisms using an inhibitor of p38 MAPK (SB203580). A rat periodontal bone defect model was built to assess its effects on bone formation in vivo by micro-CT and immunofluorescence. Our results showed SHI with no cytotoxicity could conspicuously enhanced alkaline phosphatase (ALP) activity, calcium accumulation and the expression of runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) of BMSCs in vitro. Increased bone volume/tissue volume (BV/TV) and osteopontin (OPN) expression after SHI administration further demonstrated the capacity of promoting osteogenesis of SHI in vivo. Furthermore, SHI could also increase the phosphorylation of p38. However, the phosphorylation of p38 and expression of osteogenic indicators promoted by SHI were reversed by SB203580, thereby illustrating the positive regulatory relationship between p38 MAPK and SHI-mediated osteogenesis. This finding may help SHI become a promising agent with respect to the therapy of periodontal bone defect.

Variations of root and canal morphology of mandibular second molars in Chinese individuals: a cone-beam computed tomography study.

BACKGROUND: The mandibular second molars demonstrate variations on root and canal morphology. The aim of this study was to investigate all the root canal morphology of mandibular second molars and analyze the morphological variations in patients by gender and age in a Chinese population use CBCT imaging. METHODS: Cone-beam computed tomographic images of 1200 bilateral mandibular second molars were obtained from 600 patients (300 females and 300 males) who required a preoperative assessment for implant surgery, surgical removal of impacted teeth, orthodontic treatment, surgery of maxillofacial tumour and cysts or LeFort I osteotomy. CBCT images were divided into 5 groups according to age: "15-24 years", "25-34 years", "35-44 years", "45-54 years" and "≥ 55 years"; and 2 groups by gender: "females" and "males". The following information were recorded: the number of roots and canals and their morphology, the frequency and configuration of C-shaped canals by gender, age and position (left and right). The chi-square test was used to analyse differences between groups. P value of < 0.05 was considered statistically significant. RESULTS: Of the 1200 teeth, 61% had two separate roots located mesiodistally, 35.6% had one C-shaped root. The 45.3% teeth had three canals in two-rooted mandibular second molars. The mesial root showed a Vertucci type II configuration in 28.9% cases followed by type IV(24.4%). While the distal root showed a significant higher prevalence of type I configuration in 95.6%. In the examined 1200 teeth, 430 teeth (35.8%) had C-shaped root canals. The prevalence of C-shaped root canal systems was significantly higher in females (42.5%) than in males (29.1%) (P = 0.000), and did not differ with age (P = 0.126). The 80.4% C-shaped canals were bilateral (P = 0.000) and did not differ with side (left and right) (P = 0.758). CONCLUSIONS: The most commonly observed root morphology for the mandibular second molars was 2 separate roots with three canals.The prevalence of C-shaped root canal is 35.8% and is more higher in females than in males.

Substance P participates in periodontitis by upregulating HIF-1α and RANKL/OPG ratio.

BACKGROUND: Both substance P and hypoxia-inducible factor 1 alpha (HIF-1α) are involved in inflammation and angiogenesis. However, the relationship between substance P and HIF-1α in rat periodontitis is still unknown. METHODS: Ligation-induced rat periodontitis was established to observe the distribution and expression of substance P and HIF-1α by immunohistochemistry. Rat gingival fibroblasts were cultured and stimulated with Porphyromonas gingivalis lipopolysaccharide (LPS). Recombinant substance P was applied to elaborate the relationship between substance P and HIF-1α in gingival fibroblasts in vitro. Primary mouse bone marrow-derived macrophages (BMMs) were isolated and cultured to observe the effect of substance P on receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis by TRAP staining. Western blotting was used to investigate the expression of HIF-1α, osteoprotegerin (OPG) and RANKL. RESULTS: Rat experimental periodontitis was successfully established 6 weeks after ligation. Gingival inflammatory infiltration and alveolar bone loss were observed. Positive expression of substance P was found in the infiltrating cells. Higher HIF-1α levels were observed in periodontitis compared to that of normal tissues. Substance P upregulated the level of HIF-1α in gingival fibroblasts with or without 1 µg/ml LPS in vitro (*P < 0.05). Substance P upregulated the expression of HIF-1α in RANKL-stimulated BMMs in vitro. Substance P also increased the RANKL/OPG ratio in gingival fibroblasts (*P < 0.05). Both 10 nM and 50 nM substance P promoted RANKL-induced osteoclast differentiation (*P < 0.05). CONCLUSION: Substance P participates in periodontitis by upregulating HIF-1α and the RANKL/OPG ratio.

Periodontal ligament-associated protein-1 gets involved in experimental periodontitis.

BACKGROUND AND OBJECTIVE: Periodontal ligament-associated protein-1 (PLAP-1) is an important regulator of osteogenic differentiation of periodontal ligament cells and plays important role in the homeostasis of periodontal tissues. But the role of PLAP-1 in periodontitis is poorly understood. Expressions of PLAP-1 in experimental periodontitis are observed to elucidate whether PLAP-1 gets involved in the pathogenesis of periodontitis. MATERIAL AND METHODS: Wistar rats were randomly allocated to two groups (n = 6/group): Ligation group and Control group. PLAP-1 expression in experimental periodontitis was assessed by immunohistochemistry and collagen fibers in periodontal ligament were observed using picrosirius red staining. Expressions of PLAP-1 and CD68 in periodontitis were colocalized by double-labelled immunofluorescence. To further examine the relationship between PLAP-1 and osteoclastogenesis in experimental periodontitis, acute periodontal inflammatory infiltration and alveolar bone destruction were induced by administering ligated rats with 10 ng/mL tumor necrosis factor alpha (TNF-α; ligation + TNF-α group, n = 6). Alveolar bone loss was observed by micro-computed tomography (Micro-CT), and osteoclasts were identified by tartrate-resistant acid phosphatase staining (TRAP). Expressions of PLAP-1 in TNF-α stimulated human periodontal ligament cells were also detected at 24 and 48 hours by western blotting. RESULTS: PLAP-1 expression levels in periodontal ligament cells and collagen fibers were lower in the ligation group,compared with the control group. Similarly, TNF-α decreased PLAP-1 expression in human periodontal ligament cells in vitro. Degradation or destruction of collagen fibers accompanied the reduced PLAP-1 expression in the periodontal ligament in the ligation group. Colocalization of PLAP-1 and CD68 revealed the positive relationship between PLAP-1 and CD68+ infiltrating cells in periodontitis. More PLAP-1-positive inflammatory cells were found in the ligation + TNF-α group, compared with the ligation + saline group. CONCLUSION: PLAP-1-positive inflammatory cells are involved in the pathogenesis of periodontitis. An increase in PLAP-1-positive inflammatory cell number contributes periodontal inflammation and alveolar bone loss.

[Evalation of Jingzhi Xiaoban Tablet in Improving Heart Function of Coronary Heart Disease Pa- tients by Doppler Tissue Imaging and Speckle Tracking Imaging Technology].

OBJECTIVE: To evaluate the role of Jiangzhi Xiaoban Tablet (JXT) in improving heartfunction of coronary heart disease (CHD) patients by tissue Doppler imaging (TDI) and speckle trackingimaging (STI) technology. METHODS: Recruited were 60 inpatients with confirmed CHD by coronary angiography at First Affiliated Hospital, Hunan University of Traditional Chinese Medicine from October 2013to November 2014. They were assigned to the treatment group (group A) and the control group (groupB) according to random digit table, 30 cases in each group. Patients in group A took JXT, 0.45 g/tablet,4 tablets each time, 3 times per day, while those in group B took Simvastatin Tablet, 20 mg/tablet, 1 tablet each time, once per evening. The therapeutic course for all was 8 weeks. The long axis view of theheart of 18 segments STI Peak strain LS and TDI peak systolic Sa parameters were performed in all patients before and after treatment. RESULTS: Before treatment segments of STI strain LS and TDI longitudinal peak systolic peak Sa were not statistically different between the two groups (P > 0.05). Each segment of STI peak longitudinal strain LS and TDI peak systolic Sa in the two groups were higher after treatment than before treatment (P < 0.05). After treatment each segment of STI parameters of LS and eachTDI segment parameters of Sa were significantly lower in group B than in group A (P < 0.01). CONCLUSION: JXT could improve heart function of CHD patients to different degrees, and its curative effect was betterthan that of routine Western medicine (Simvastatin Tablets) treatment.

Periodontal ligament-associated protein-1 promotes osteoclastogenesis in mice by modulating TGF-ß1/Smad1 pathway.

BACKGROUND: Periodontal ligament-associated protein-1 (PLAP-1), an important target molecule of osteoarthritis research, may affect alveolar bone resorption. The aim of our study was to comprehensively and systematically detect the effect of PLAP-1 on alveolar bone resorption and the underlying mechanism in PLAP-1 knockout mouse models. METHODS: We used a PLAP-1 knockout (C57BL/6N-Plap-1-/- ) mouse model to investigate the effect of PLAP-1 on osteoclast differentiation and the underlying mechanism by adding Porphyromonas gingivalis lipopolysaccharide to stimulate bone marrow-derived macrophages. The effect of PLAP-1 on alveolar bone resorption and the underlying mechanism were studied using a ligature periodontitis model, with microcomputed tomography imaging, immunochemistry, and immunofluorescence. RESULTS: The in vitro analysis results demonstrated that PLAP-1 knockout significantly inhibited osteoclast differentiation under both normal and inflammatory conditions. Bioinformatic analysis, immunofluorescence, and co-immunoprecipitation showed colocalization and interaction between PLAP-1 and transforming growth factor beta 1 (TGF-ß1). The phosphorylation of Smad1 was reduced in the PLAP-1 knockout cells compared with that in the cells from wild-type mice. The in vivo analysis results demonstrated that PLAP-1 knockout decreased bone resorption and the levels of osteoclast differentiation markers in experimental periodontitis compared with those in wild-type mice. Immunofluorescence staining confirmed colocalization of PLAP-1 and TGF-ß1 in the experimental periodontitis model. The phosphorylation level of Smad1 was significantly reduced in PLAP-1 knockout mice compared with that in wild-type mice. CONCLUSIONS: This study revealed that the knockout of PLAP-1 inhibits osteoclast differentiation and decreases alveolar bone resorption through the TGF-ß1/Smad1 signaling pathway, which could serve as an innovative target for the prevention and treatment of periodontitis.

Periapical lesion detection in periapical radiographs using the latest convolutional neural network ConvNeXt and its integrated models.

To overcome the limitation of a single classification model's inability to simultaneously identify multiple lesion targets within periapical radiographs, This study proposes YoCNET (Yolov5 + ConvNeXt), a novel deep learning integrated model. YoCNET leverages the target detection capability of Yolov5 and the image classification capability of ConvNeXt to achieve automatic segmentation of individual teeth and concurrent detection of periapical lesions across multiple teeth. A dataset of 1,305 periapical radiographs was used to train and validate the ConvNeXt and ResNet34 models, with an 8:2 split for training and validation. Deciduous teeth were excluded from the dataset. Furthermore, 717 individual teeth images were extracted from 200 previously unused periapical radiographs for integrated model validation. Evaluation metrics included accuracy, precision, sensitivity, F1 score, AUC (Area Under Curve), and a confusion matrix.The YoCNET integrated model demonstrated values of 90.93%, 98.88%, 85.30%, 0.9159, and 0.9757 for accuracy, precision, sensitivity, F1 score, and AUC, respectively. These metrics were superior to those achieved by the YoRNET (Yolov5 + ResNet34) integrated model, which recorded 80.47%, 83.78%, 82.16%, 0.8296, and 0.8822. The integrated model achieved high accuracy and efficiency in automatic teeh segmentation by Yolov5 and in automatically detecting multiple periapical lesions by ConvNeXt. YoCNET exhibited superior overall data performance, making it a more suitable deep learning integrated model for clinical applications.

TIPE2 regulates periodontal inflammation by inhibiting NF-κB p65 phosphorylation.

BACKGROUND: The roles and molecular mechanisms of tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) in periodontitis remain largely unknown. OBJECTIVE: This study aimed to determine the expression of TIPE2 and NF-κB p65 in rat Porphyromonas gingivalis-induced periodontics in vivo. METHODOLOGY: Periodontal inflammation and alveolar bone resorption were analyzed using western blotting, micro-computed tomography, TRAP staining, immunohistochemistry, and immunofluorescence. THP-1 monocytes were stimulated using 1 µg/ml Pg. lipopolysaccharide (Pg.LPS) to determine the expression of TIPE2 in vitro. TIPE2 mRNA was suppressed by siRNA transfection, and the transfection efficiency was proven using western blotting and real-time PCR. The NF-κB pathway was activated by treating the cells with 1 µg/ml Pg.LPS to explore related mechanisms. RESULTS: The expression of both TIPE2 and NF-κB p65 was increased in the gingival tissues of rat periodontitis compared with normal tissues. Positive expression of TIPE2 was distributed in inflammatory infiltrating cells and osteoclasts in the marginal lacunae of the alveolar bone. However, strong positive expression of TIPE2 in THP-1 was downregulated after Pg.LPS stimulation. TIPE2 levels negatively correlated with TNF-α and IL-1ß. Decreased TIPE2 in THP-1 further promoted NF-κB p65 phosphorylation. Mechanistically, TIPE2 knockdown upregulated NF-κB signaling pathway activity. CONCLUSIONS: Taken together, these findings demonstrate that TIPE2 knockdown aggravates periodontal inflammatory infiltration via NF-κB pathway. Interventions aimed at increasing TIPE2 may help in the therapeutic applications for periodontitis.

Characterizations of alveolar repair after mandibular second molar extraction: an experimental study in rats.

BACKGROUND: Characterizations of rat mandibular second molar extraction socket with significantly different buccal and lingual alveolar ridge width remain unclear. OBJECTIVE: To observe alterations in the alveolar ridge after extraction of mandibular second molars, and to examine processes of alveolar socket healing in an experimental model of alveolar ridge absorption and preservation. METHODOLOGY: Eighteen Wistar rats were included and divided into six groups regarding healing time in the study. Bilateral mandibular second molars were extracted. The rats with tooth extraction sockets took 0, 1.5, 2, 3, 4 and 8 weeks of healing. Histological observation, tartrate-resistant acidic phosphatase (TRAP) staining, Masson's trichrome staining, immunohistochemical staining and micro-computed tomography (micro-CT) were applied to estimate alterations in the alveolar ridge. RESULTS: Different buccal and lingual alveolar ridge width led to different height loss. Lingual wall height (LH) decreased significantly two weeks after tooth extraction. Buccal wall height rarely reduced its higher ridge width. From two to eight weeks after extraction, bone volume (BV/TV), density (BMD), and trabecular thickness (Tb.Th) progressively increased in the alveolar socket, which gradually decreased in Tb.Sp and Tb.N. LH showed no significant change during the same period. Osteogenic marker OCN and OPN increased during bone repair from two to eight weeks. The reduced height of the lingual wall of the tooth extraction socket was rarely repaired in the later repair stage. Osteoclast activity led to absorption of the alveolar ridge of the alveolar bone wall within two weeks after operation. We observed positive expression of EMMPRIN and MMP-9 in osteoclasts that participated in the absorption of the spire region. CONCLUSION: Extraction of rat mandibular second molars may help the study of alveolar ridge absorption and preservation. The EMMPRIN-MMP-9 pathway may be a candidate for further study on attenuating bone resorption after tooth extraction.

Ursolic Acid Loaded-Mesoporous Hydroxylapatite/ Chitosan Therapeutic Scaffolds Regulate Bone Regeneration Ability by Promoting the M2-Type Polarization of Macrophages.

PURPOSE: Mesoporous hydroxylapatite (MHAP) might be important for bone regeneration, and ursolic acid (UA) has anti-inflammatory effects. Accordingly, we developed, for the first time, ursolic acid-loaded MHAP-chitosan (MHAP-CS-UA) scaffolds to treat bone defects. METHODS: In vitro, we synthesize biomaterial scaffolds. By SEM, XRD, EDS and FTIR, we test the performance of the hybrid scaffolds. By drug release, flow cytometry, immunofluorescence, alizarin red staining, and Western blotting, we test the anti-inflammatory and osteo-inductive properties of scaffolds. In vivo, we verify osseointegration ability and bone regeneration. RESULTS: The MHAP is a rod-shaped structure with a length of 100~300nm and a diameter of 40~60nm. The critical structure gives the micro-scaffold a property of control release due to the pore sizes of 1.6~4.3 nm in hydroxyapatite and the hydrogen bonding between the scaffolds and UA drugs. The released UA drugs could notably inhibit the polarization of macrophages to pro-inflammatory macrophages (M1 type) and promote the expression of osteogenic-related genes (COL1, ALP and OPG) and osteogenic-related proteins (BMP-2, RUNX2 and COL1). CONCLUSION: The MHAP-CS-UA scaffolds have good anti-inflammatory, osseointegration, osteo-inductivity and bone regeneration. And they will be the novel and promising candidates to cure the bone disease.

Identification of Immune Subtypes for Predicting the Prognosis of Patients in Head and Neck Squamous Cell Carcinoma.

Head and neck squamous cell carcinoma (HNSCC) is a common malignancy with poor prognosis and immune response, which plays an important role in tumor progression. Recently, immunotherapies have revolutionized the therapeutic means of malignancies including HNSCC. However, the relationship between immunophenotypes of HNSCC and its clinical response to immune-checkpoint inhibitors remains unclear. We aim to identify molecular subtyping related to distinct immunophenotypes in HNSCC. Consensus clustering algorithm was conducted for subtyping. Immunophenotypes between subtypes were compared according to infiltrating immunocytes, immune reactions, major histocompatibility complex (MHC) family, immunoinhibitory, immunostimulatory and immune scores. The relationship between immunophenotype and genotype was investigated from gene mutation and tumor mutation burden. The potential response of Immune-checkpoint blockade (ICB) therapy was estimated with TIDE and ImmuCellAI algorithms, and immune-checkpoint genes. The immune characteristics were also investigated. Biological functions were annotated by the gene-set enrichment analysis (GSEA) algorithm. Two distinct immune subtypes of HNSCC with different survival outcomes, biological characteristics, immunophenotype, and ICB response were identified. The subtype-1 was featured with better prognosis, more infiltrated immunocytes, stronger immune reaction, higher immune-related gene expression, higher immune-checkpoint gene expression (PD-1, PD-L1, and CTLA-4), and better ICB response. A higher immune response in subtype-1 was also revealed by GSEA. Subtype-1 possessed a higher immune response and more sensitivity to ICB therapy leading to a better prognosis. These findings may shed promising light on the immunotherapy strategy in HNSCC.

Semaphorin 3A promotes the osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells in inflammatory environments by suppressing the Wnt/ß-catenin signaling pathway.

After periodontal treatment, the local inflammatory environment surrounding periodontal tissues cannot be entirely eliminated. The means by which alveolar bone repair and regeneration are promoted in inflammatory environments have important clinical significance. As a powerful protein that promotes the differentiation of osteocytes, semaphorin 3A (Sema3A) shows potential for bone regeneration therapy. However, the effect of Sema3A on osteogenic differentiation in an inflammatory environment, as well as the underlying mechanism, have not yet been explored. We used lentivirus to transduce rat bone marrow-derived mesenchymal stem cells (rBMSCs) to stably overexpress Sema3A. Lipopolysaccharide from Escherichia coli (E. coli LPS) was used to stimulate rBMSCs to establish an inflammatory environment. ALP staining, Alizarin red staining, ALP activity tests, quantitative RT-PCR (qRT-PCR), and Western blotting were used to elucidate the effect of Sema3A on the osteogenesis of rBMSCs in inflammatory environments. XAV939 and LiCl were used to determine whether the Wnt/ß-catenin signaling pathway was involved in attenuating the inhibition of Sema3A-induced osteogenic differentiation by LPS. The qRT-PCR and Western blot results demonstrated that the lentiviral vector (LV-NC) and lentiviral-Sema3A (LV-Sema3A) were successfully transduced into rBMSCs. An inflammatory environment could be established by stimulating rBMSCs with 1 µg/ml E. coli LPS. After Sema3A overexpression, mineral deposition was exacerbated, and the BSP and Runx2 gene and protein expression levels were increased. Furthermore, E. coli LPS activated the Wnt/ß-catenin signaling pathway and decreased rBMSC osteogenesis, but these effects were attenuated by Sema3A. In conclusion, Sema3A could protect BMSCs from LPS-mediated inhibition of osteogenic differentiation in inflammatory environments by suppressing the Wnt/ß-catenin pathway.

The combined application of rat bone marrow mesenchymal stem cells and bioceramic materials in the regeneration of dental pulp-like tissues.

This study aims to observe the effects of the combined application of rat bone marrow mesenchymal stem cells (rBMSCs) and a bioceramic material on pulp-like tissue formation. Rat incisor root fragments without pulp tissues were prepared and filled with a collagen scaffold seeded with rBMSCs, while one side of the root segment was covered by a bioceramic material (iRoot BP). After they were cultured for 12 hours, the root fragments were implanted subcutaneously for 3 months. Hematoxylin and eosin (HE) staining was applied to observe the biocompatibility and the formation of pulp-like tissues. The incisor root fragments were divided into three parts (BP1/3, M1/3, and D1/3) to analyze the areas and the number of new vessels. Immunohistochemical staining of the neuroendocrine marker PGP9.5, the dentin sialophosphoprotein (DSPP), and the vascular endothelial growth factor (VEGF) was applied to observe the formation of the pulp-like tissues. Root fragments filled with only the collagen scaffold were used as a control. Three months after the implantation, the root fragments were collected, and they were surrounded by a transparent tissue membrane with a good blood supply. The root fragment cavity was filled with pink vascularized pulp-like tissue. According to the HE results, iRoot BP had good biocompatibility with the new pulp-like tissues and a few infiltrating inflammatory cells. Increases in the number and area of the new blood vessels were observed in BP1/3 compared with the other two parts. The PGP9.5 and DSPP expressions showed that the newly formed tissues were similar to normal pulp tissues. iRoot BP has good biocompatibility and increases the number and area of new blood vessels. The combined application of stem cells and bioceramic materials may be a better method for pulp revascularization.

Association of high HIF-1α levels in serous periodontitis with external root resorption by the NFATc1 pathway.

Whether external root resorption is associated with hypoxia in the periodontal ligaments of teeth with severe periodontitis remains unclear. Hypoxia inducible factor-1α (HIF-1α) expression and external resorption sites in the periodontal ligaments of these teeth were observed to elaborate upon the relationship between hypoxia and external root resorption in severe periodontitis. Histological analysis was performed to observe external root resorption. The expressions of HIF-1α and Nuclear factor-activated T cells c1 (NFATc1) in the periodontal ligaments were detected by immunofluorescence, western blotting and real-time PCR. Bone marrow macrophages (BMMs) were stimulated by Porphyromonas gingivalis lipopolysaccharide (Pg.LPS) and cultured under hypoxia in vitro. High levels of HIF-1α and NFATc1 were detected in severe periodontitis. HIF-1α positive-cells were observed in the external resorption sites. Hypoxia promoted Pg.LPS-stimulated osteoclastogenesis of BMMs and bone resorption by the NFATc1 pathway. Increased HIF-1α in severe periodontitis are associated with external root resorption by the NFATc1 pathway.

High levels of HIF-1ɑ in hypoxic dental pulps associated with teeth with severe periodontitis.

In this study we investigated the expression of HIF-1ɑ in dental pulps of the teeth with severe periodontitis. The expression of HIF-1ɑ in dental pulps of the teeth with severe periodontitis was detected by immunohistochemistry, immunofluorescence and real-time PCR. Bone marrow macrophages (BMMs) were cultured under hypoxia in vitro. HIF-1ɑ, osteoclast-specific factors (NFATc1, CTSK and c-fos) and RANKL-induced osteoclastogenesis were evaluated by immunofluorescence, TRAP staining and western blotting. High levels of HIF-1ɑ protein were detected in dental pulps of teeth with severe periodontitis, whereas few positive HIF-1ɑ expressions were detected in healthy dental pulps. Hypoxia occurred in the dental pulps in response to heavy periodontitis. Many HIF-1ɑ-positive infiltratory inflammatory cells were observed around blood vessels. Tooth internal resorption was found in some teeth with severe periodontitis. The HIF-1ɑ levels were upregulated in BMMs under hypoxia, which also promoted osteoclast formation and resorption by NFATc1, CTSK and c-fos. Teeth with severe periodontitis show hypoxic dental pulps and increased potential of osteoclastic differentiation.