miR-155-5p/Bmal1 Modulates the Senescence and Osteogenic Differentiation of Mouse BMSCs through the Hippo Signaling Pathway.

BACKGROUND: The core clock gene brain and muscle ARNT like-1 (Bmal1) is involved in the regulation of bone tissue aging. However, current studies are mostly limited to the establishment of the association between Bmal1 and bone senescence, without in-depth exploration of its main upstream and downstream regulatory mechanisms. METHODS: The luciferase reporter assay, RT-qPCR and Western blotting were performed to detect the interaction between miR-155-5p and Bmal1. The effects of miR-155-5p and Bmal1 on the aging and osteogenic differentiation ability of mouse bone marrow mesenchymal stem cells (BMSCs) were investigated by cell counting kit-8 (CCK-8) assay, flow cytometry, ß-gal staining, alkaline phosphatase quantitative assay and alizarin red staining in vitro. The potential molecular mechanism was identified by ChIP-Seq, RNA-seq database analysis and immunofluorescence staining. RESULTS: The expression of Bmal1 declined with age, while the miR-155-5p was increased. miR-155-5p and Bmal1 repressed each other's expression, and miR-155-5p targeted the Bmal1. Besides, miR-155-5p inhibited the proliferation and osteogenic differentiation of BMSCs, promoted cell apoptosis and senescence, inhibited the expression and nuclear translocation of YAP and TAZ. However, Bmal1 facilitated the osteogenic differentiation and suppressed the aging of BMSCs, meanwhile inactivated the Hippo pathway. Moreover, YAP inhibitors abrogated the positive regulation of aging and osteogenic differentiation in BMSCs by miR-155-5p and Bmal1. CONCLUSION: In mouse BMSCs, miR-155-5p and Bmal1 regulated the aging and osteogenic differentiation ability of BMSCs mainly through the Hippo signaling pathway. Our findings provide new insights for the interventions in bone aging.

Correlation between gingival phenotype in the aesthetic zone and craniofacial profile-a CBCT-based study.

OBJECTIVES: To investigate the correlation between gingival phenotype and craniofacial profile and to evaluate the morphology of periodontal supporting tissues in the maxillary and mandibular anterior zones. MATERIALS AND METHODS: A total of 66 patients with 264 central incisors in good periodontal health were included in this cross-sectional study. CBCT images were used to assess gingiva and alveolar bone thickness of the maxillary and mandibular incisors at four vertical levels. Cephalometric analysis was used to assess the sagittal profile of the craniofacial structures. Gingival thickness was compared in patients with different craniofacial profiles based on ANB value. Linear regression coefficients adjusted by age and gender were used to evaluate the correlation between gingival thickness and the cephalometric parameters. RESULTS: Individuals with a smaller ANB value (ANB< 2) presented with thinner supporting tissue and a keratinized gingiva width in the anterior zone. Labial gingival thickness on the mandibular incisors at the cementoenamel junction (G1) and at the alveolar bone crest (G2) was positively related to cephalometric measures, indicating a maxillae-mandibular sagittal relationship (ANB value, Wits appraisal, A-NPog value). CONCLUSIONS: A moderate correlation was found between mandibular gingival thickness and the sagittal craniofacial profile. Patients with a concave craniofacial profile had a smaller keratinized gingiva width and gingival thickness in the aesthetic zone. CLINICAL RELEVANCE: Knowledge of these features on supporting tissue and their correlations with craniofacial morphology will help clinicians to develop a reasonable treatment plan and make decisions to achieve the best aesthetic outcome.

Treatment of Class II malocclusion with tooth movement through the maxillary sinus.

This case report describes the successful extraction treatment of a Class II malocclusion with excessive maxillary sinus pneumatization. A 20-year-old man sought treatment with the major complaint of protrusive mouth and anterior teeth. He was diagnosed with a skeletal Class II relationship and protrusion of the maxilla. The clinical examination showed a severe Class II molar relationship with excessive overjet and deep overbite. Panoramic radiograph showed obvious maxillary sinus pneumatization bilaterally. Three premolars and one deciduous molar were extracted, and spaces were used to correct molar relationship and retract maxillary incisors. Light forces and low speed movement were applied to overcome the challenge of moving teeth through the maxillary sinus wall. Balanced facial esthetic and stable occlusion were obtained posttreatment with a notable bone formation of the maxillary sinus wall. This result highlights the possibility of tooth movement through cortical floor with bone remodeling and no obvious complications.