The role of PHF8 and TLR4 in osteogenic differentiation of periodontal ligament cells in inflammatory environment.

BACKGROUND: Histone methylation is considered to play an important role in the occurrence and development of periodontitis. Plant homeodomain finger protein 8 (PHF8), a histone demethylase, has been shown to regulate inflammation and osteogenic differentiation of bone marrow stromal cells (BMSCs). This study aimed to detect the functions of PHF8 and TLR4 in osteogenic differentiation in an inflammatory environment induced by Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) METHODS: A periodontitis mouse model was established, and the mice were treated with TAK-242. Immunohistochemical staining was used to detect the expression of PHF8 in periodontal tissue. Periodontal ligament cells (PDLCs) were treated with mineralization induction medium supplemented with Pg-LPS and/or TAK-242, and a Cell Counting Kit-8 (CCK-8) assay was used to detect the proliferation of PDLCs. Real-time PCR and western blotting were used to detect the mRNA and protein expression levels, respectively, of PHF8, toll-like receptor 4 (TLR4) and the other osteogenic markers alkaline phosphatase (ALP), osteocalcin (OCN), Special AT-rich sequence-binding protein 2 (Satb2) and Runt-related transcription factor 2 (Runx2) RESULTS: Periodontitis reduced PHF8 expression in periodontal tissue, and TAK-242 partially reversed this downregulation. An in vitro experiment revealed that the mRNA and protein expression levels of PHF8 were significantly upregulated during the osteogenic differentiation of PDLCs. Alizarin red staining showed that the mineralized nodules of PDLCs in osteogenic induction group were more than those in control group. Real-time PCR and western blot results indicated that Pg-LPS inhibited PHF8 expression and upregulated TLR4 expression in PDLCs. TAK-242 inhibited TLR4 and partially reversed the inhibition of PHF8 expression and osteogenic differentiation induced by Pg-LPS in PDLCs CONCLUSION: PHF8 and TLR4 play important roles in periodontitis. Pg-LPS inhibits the expression of PHF8 via upregulation of TLR4 and might further inhibit the osteogenic differentiation of PDLCs. However, the specific mechanisms involved remain to be explored.

[Biocompatibility of poly-L-lactic acid/Bioglass-guided bone regeneration membranes processed with oxygen plasma].

OBJECTIVE: To prepare and characterize a nano-scale fibrous hydrophilic poly-L-lactic acid/ Bioglass (PLLA/BG) composite membrane and evaluate its biocompatibility as a composite membrane for guiding bone regeneration (GBR). METHODS: PLLA/BG-guided bone regeneration membrane was treated by oxygen plasma to improved its hydrophilicity. The growth of MG-63 osteoblasts on the membrane was observed using Hoechst fluorescence staining, and the biocompatibility of the membrane was evaluated by calculating the cells adhesion rate and proliferation rate. Osteogenesis of MG-63 cells was assessed by detecting alkaline phosphatase (ALP), and the formation of calcified nodules and cell morphology changes were observed using scanning electron microscope (SEM). RESULTS: The cell adhesion rates of PLLA/BG-guided bone regeneration membrane treated with oxygen plasma were (30.570±0.96)%, (47.27±0.78)%, and (66.78±0.69)% at 1, 3, and 6 h, respectively, significantly higher than those on PLLA membrane and untreated PLLA/BG membrane (P<0.01). The cell proliferation rates on the 3 membranes increased with time, but highest on oxygen plasma-treated PLLA/BG membrane (P<0.01). Hoechst fluorescence staining revealed that oxygen plasma treatment of the PLLA/BG membrane promoted cell adhesion. The membranes with Bioglass promoted the matrix secretion of the osteoblasts. Under SEM, the formation of calcified nodules and spindle-shaped cell morphology were observed on oxygen plasma-treated PLLA/BG membrane. CONCLUSION: Oxygen plasma-treated PLLA/BG composite membrane has good biocompatibility and can promote adhesion, proliferation and osteogenesis of the osteoblasts.

Characterization of Silk Fibroin/Chitosan 3D Porous Scaffold and In Vitro Cytology.

Bone tissue engineering is a powerful tool to treat bone defects caused by trauma, infection, tumors and other factors. Both silk fibroin (SF) and chitosan (CS) are non-toxic and have good biocompatibility, but are poor biological scaffolds when used alone. In this study, the microscopic structure and related properties of SF/CS composite scaffolds with different component ratios were examined. The scaffold material most suitable for osteoblast growth was determined, and these results offer an experimental basis for the future reconstruction of bone defects. First, via freeze-drying and chemical crosslinking methods, SF/CS composites with different component ratios were prepared and their structure was characterized. Changes in the internal structure of the SF and CS mixture were observed, confirming that the mutual modification between the two components was complete and stable. The internal structure of the composite material was porous and three-dimensional with a porosity above 90%. We next studied the pore size, swelling ratio, water absorption ratio, degradation and in vitro cell proliferation. For the 40% SF-60% CS group, the pore size of the scaffold was suitable for the growth of osteoblasts, and the rate of degradation was steady. This favors the early adhesion, growth and proliferation of MG-63 cells. In addition to good biocompatibility and satisfactory cell affinity, this material promotes the secretion of extracellular matrix materials by osteoblasts. Thus, 40% SF-60% CS is a good material for bone tissue engineering.

Silencing Dicer expression enhances cellular proliferative and invasive capacities in human tongue squamous cell carcinoma.

microRNAs (miRNAs) are aberrantly expressed in cancer. An enzyme essential for miRNA processing is Dicer, whose expression is deregulated in diverse types of cancer and correlates with tumor progression. However, whether the regulation of Dicer expression affects tongue squamous cell carcinoma is unknown. In the present study, we investigated how silencing the expression of Dicer alters cell proliferation, cell cycle patterns, and cell migration and invasion in the Tca-8113 tongue squamous cell carcinoma cell line. Dicer expression levels were determined using quantitative PCR and western blot analysis in normal oral gingival epithelial cells and in two tongue squamous cell carcinoma lines, Tca-8113 and UM-1. Tca-8113 cells were transfected with Dicer siRNA or a negative control siRNA. Cell proliferation was determined using the MTT assay and the cell cycle was examined using flow cytometry. Cell migration and invasion changes were evaluated using wound-healing, adherence and Transwell assays. Dicer was expressed at lower levels in the tongue squamous cell carcinoma cell lines Tca-8113 and UM-1 compared to normal gingival epithelial cells, and less Dicer was expressed in UM-1 cells compared to Tca-8113 cells. Notably, Tca-8113 cells transfected with Dicer siRNA had significantly higher proliferative and invasive abilities than cells transfected with the negative control siRNA or non-transfected cells. Silencing Dicer may promote the progression of tongue squamous cell carcinoma. Dicer could serve a promising biomarker and a potential therapeutic target for tongue squamous cell carcinoma.

Reconstruction of full-thickness cheek defects with combined temporalis myofacial and facial-cervico-pectoral flaps.

OBJECTIVE: The objective of this study was to assess using the temporal myofacial flaps (TMFF) and the facial-cervico-pectoral flap (FCPF) to provide both inner and outer linings for large full-thickness cheek defects following ablative oral cancer surgery. STUDY DESIGN: Twelve patients with malignant tumors in the buccal region were treated by extensive surgical dissection, and the cheek mucosa defects were repaired with the TMFF and the cheek skin defects were reconstructed with the FCPF. There were 9 male and 3 female patients, age range from 18 to 70 years (mean 52.8). The full-thickness cheek defects ranged from 7 x 6 cm to 10 x 8 cm in size. RESULTS: No patient had complete loss of flap; 3 patients had minor complications (TMFF and FCPF partial necrosis and FCPF distal dehiscence) all of which settled with conservative management. Mouth opening was normal in 10 patients, and facial contour was satisfactory in 8 patients. The follow-up period varied from 6 to 26 months (mean 15.2); 3 tumors had local recurrences and 2 patients died from tumor metastasis. CONCLUSION: We found the technique to be anatomically sound, technically easy and reliable, and believe it is a useful method for the reconstruction of large full-thickness cheek defects.