Effects of G-CSF on hPDLSC proliferation and osteogenic differentiation in the LPS-induced inflammatory microenvironment.

BACKGROUND: Periodontitis is a chronic infectious disease of periodontal support tissue caused by microorganisms in dental plaque, which causes alveolar bone resorption and tooth loss. Periodontitis treatment goals include prevention of alveolar bone resorption and promotion of periodontal regeneration. We previously found that granulocyte colony-stimulating factor (G-CSF) was involved in periodontitis-related alveolar bone resorption through induction of an immune response and subsequent destruction of periodontal tissue. However, the mechanisms underlying the effects of G-CSF on abnormal bone remodeling have not yet been fully elucidated. Human periodontal ligament stem cells (hPDLSCs) are major modulators of osteogenic differentiation in periodontal tissues. Thus, the aim of this study was to investigated whether G-CSF acts effects on hPDLSC proliferation and osteogenic differentiation, as well as periodontal tissue repair. METHODS: hPDLSCs were cultured and identified by short tandem repeat analysis. The expression patterns and locations of G-CSF receptor (G-CSFR) on hPDLSCs were detected by immunofluorescence analysis. The effects of G-CSF on hPDLSCs in a lipopolysaccharide (LPS)-induced inflammatory microenvironment were investigated. Specifically, Cell-Counting Kit 8 (CCK8) and Alizarin red staining were used to examine hPDLSC proliferation and osteogenic differentiation; reverse transcription-polymerase chain reaction was performed to detect the expression patterns of osteogenesis-related genes (alkaline phosphatase [ALP], runt-related transcription factor 2 [Runx2], and osteocalcin [OCN]) in hPDLSCs; and Western blotting was used to detect the expression patterns of phosphatidylinositol 3-kinase (PI3K) and protein kinase B (Akt) of PI3K/Akt signaling pathway. RESULTS: hPDLSCs exhibited a typical spindle-shaped morphology and good clonogenic ability. G-CSFR was mostly localized on the cell surface membrane. Analyses showed that G-CSF inhibited hPDLSC proliferation. Also, in the LPS-induced inflammatory microenvironment, G-CSF inhibited hPDLSC osteogenic differentiation and reduced the expression levels of osteogenesis-related genes. G-CSF increased the protein expression levels of hPDLSC pathway components p-PI3K and p-Akt. CONCLUSIONS: We found that G-CSFR was expressed on hPDLSCs. Furthermore, G-CSF inhibited hPDLSC osteogenic differentiation in vitro in the LPS-induced inflammatory microenvironment.

Preparation of fluorescent organometallic porphyrin complex nanogels of controlled molecular structure via reverse-emulsion click chemistry.

Here, we are the first to report a novel approach to preparing well-defined poly(ethylene glycol) (PEG) fluorescent nanogels, with well-defined molecular structures and desired functionalities via reverse (mini)emulsion copper(I)-catalyzed azide-alkyne cycloaddition (REM-CuAAC). Nanogels with hydroxyl groups and Ga-porphyrin complex (Ga-porphyrin-OH nanogels), as well as with Ga-porphyrin complex and folate functional groups (Ga-porphyrin-FA), are successfully prepared. Nanogels of 30 and 120 nm in diameter are obtained and they exhibit an emission maxima within the wavelength range 700-800 nm. The nanogels could find uses in near infrared (NIR) imaging attributable to their fluorescence and their functionality for cell affinity.

Mechanism of deep eutectic solvents enhancing catalytic function of cytochrome P450 enzymes in biosynthesis and organic synthesis.

Indigo is an insoluble blue dye, which generates serious pollution in its production process. Increasing focus has come to the biosynthesis of indigo that are more environment-preserved and high-efficient. Hence, this study was designed to explore the specific role of various deep eutectic solvents (DESs) on cytochromeP45-BM-3 catalyzing indole to produce indigo. DESs were synthesized by heating and stirring. The structure of the solvent was analyzed by nuclear magnetic resonance (NMR) and fourier transform infrared spectrum (FT-IR), and the relationship between the viscosity, density and refractive index of the solvent, and the water content of the solvent was examined. Circular dichroism spectrometer was used to detect the tertiary structure of the enzyme protein. The effect of solvent type, concentration, pH, temperature, and water content on the catalytic activity and stability of P450 BM-3 was measured using an ultraviolet spectrophotometer. A new solvent biphasic system was established using DESs and buffers, and indigo was prepared using recombinant E. coli-biocatalyzed indole. DESs were low-melting eutectics formed by molecules interaction of components through hydrogen bonding. The physical properties of DESs such as density, viscosity, and refractive index varied with water content and temperature of the solvent. The pH, water content, and temperature of DESs were positively correlated with the catalytic activity of P450 BM-3. To sum up, DESs can improve the catalytic activity and thermal stability of P450 BM-3. Indigo can be efficiently prepared using the DESs-buffer biphasic system.

Oral bone loss induced by mineral deficiency in a rat model: effect of a synthetic bone mineral (SBM) preparation.

UNLABELLED: Osteoporosis affects the craniofacial and oral structures and has been associated with periodontal bone loss, tooth loss and reduced jaw bone mass. OBJECTIVE: This study aimed to test the therapeutic efficacy of synthetic bone mineral (SBM) in minimizing alveolar bone loss induced by mineral deficiency in a rat model. SBM consists of a calcium carbonate apatite (similar to bone apatite) matrix incorporating magnesium, zinc, and fluoride ions. DESIGN: Thirty female Sprague Dawley rats (2 months old) were randomly distributed into 3 groups (10 rats per group): GA (control), on basic diet; GB, on mineral deficient (MD) diet; and GC, on MD+SBM. The rats were sacrificed after 3 months, the jawbones were isolated and the soft tissues removed. Bone density was determined using X-ray radiography (Faxitron); mandibular cortical width, panoramic mandibular index, and alveolar resorption degree (M/M ratio) using BioquantOsteo; and bone micro-architecture micro-computed tomography and scanning electron microscopy. RESULTS: Compared to control (GA), the rats on MD diet (GB) experienced significant mandibular bone loss while the rats on MD+SBM diet (GC) experienced significantly less bone loss compared to the GB group. CONCLUSION: SBM, administered orally, may have the potential as an osteoporosis therapeutic agent in minimizing or preventing alveolar bone loss induced by mineral deficiency.

Highly efficient release of lovastatin from poly(lactic-co-glycolic acid) nanoparticles enhances bone repair in rats.

Lovastatin exhibits higher thermal stability and lower degradation rate than simvastatin. However, the amount of research studying a lovastatin delivery device has been far less than similar research on simvastatin. As a consequence, a high lovastatin release rate system has not been developed. We hypothesized that highly efficient release of lovastatin from poly(lactic-co-glycolic acid) (PLGA) nanoparticles in a short-term release (7 days) could provide an effective delivery system for bone repair. This study optimized the emulsion (o/w) technique in the fabrication process for PLGA nanoparticles, thereby producing the first recorded case of a high release rate (97%) of lovastatin. We also calculated the calibration curve of lovastatin using a UV spectrometer. The results demonstrated that the ALPase activity in human osteoblasts could be significantly stimulated by lovastatin carried in PLGA nanoparticles, but was prominently decreased by free lovastatin with the concentration higher than 4 µg/ml. Animal studies showed that the amount of lovastatin contained in 1 mg PLGA was the optimum dosage. These results suggest the new lovastatin-releasing PLGA delivery device exhibits potential for clinical treatment of bony defects.

Preparation and applications of functional nanofibers based on the combination of electrospinning, controlled radical polymerization and 'Click Chemistry'.

This feature article provides an overview of the preparation of functional nanofibers by combined electrospinning, controlled radical polymerization and 'Click Chemistry'. A combination of the powerful capability of controlled radical polymerization and 'Click Chemistry' for the synthesis of functional macromolecules and on surface modification as well as their wide applicability to electrospinning materials, functional nanofibers with a crosslinked structure, core-shell structures, and switchable surface properties etc. were prepared. In addition, the applications of the functional nanofibers in antibacterial fields and controlled release are also explored.

Simultaneous incorporation of carbonate and fluoride in synthetic apatites: Effect on crystallographic and physico-chemical properties.

The mineral in bone is an impure hydroxyapatite, with carbonate as the chief minor substituent. Fluoride has been shown to stimulate osteoblastic activity and inhibit osteoclastic resorption in vitro. CO(3)- and F-substituted apatite (CFA) has been considered as potential bone graft material for orthopedic and dental applications. The objective of this study was to determine the effects of simultaneously incorporated CO(3) and F on the crystallographic physico-chemical properties of apatite. The results showed that increasing CO(3) and Na content in apatites with relatively constant F concentration caused a decrease in crystallite size and an increase in the extent of calcium release; increasing F content in apatites with relatively constant CO(3) concentration caused an increase in crystallite size and a decrease in the extent of Ca release. These findings suggest that CFAs as bone graft materials of desired solubility can be prepared by manipulating the relative concentrations of CO(3) and F incorporated in the apatite.

[An experimental study on rabbit's radial bone defect healed by application of mimetic periosteum with tissue-engineered bone].

OBJECTIVE: The purpose of this study is to investigate the osteogenic potential and possibility of combination application of mimetic osteoinductive periosteum with tissue-engineered bone. METHODS: The three-dimensional construction of tissue-engineered bone was made by implantation of adipose derived stromal cells (ADSCs) into rhBMP-2 mediated bio-derived carrier, and mimetic periosteum was constructed by loading ADSCs into Cs-Col-beta3-TCP with rhBMP-2. 10 mm defects of right radiuses were established in adult New Zealand rabbits, group A was transplanted by tissue-engineered bone with mimetic periosteum, group B was implanted by tissue-engineered bone, and group C was implanted by mimetic periosteum, group D was transplanted by bio-derived compound bone as blank scaffold. X-ray, histology, immunohistochemistry stain, dural energy X-ray absorptiometry (DEXA) and transmission electron microscopy (TEM) examinations were performed at different periods. RESULTS: Group A played a predominant role in process of new tissue regeneration and mature bone reconstitution, defect completely healed at 12 weeks. Group B showed primary repair, group C also existed in modeling stage. While, group D displayed retard regeneration with poor osteogenic capacity. DEXA result showed that group A had statistical significance over control group according to data of BMC and BMD ( P < 0.05). CONCLUSIONS: Enhanced osteogenic potential can be obtained by using tissue-engineered bone with mimetic osteoinductive periosteum. Defect can be healed with concord pattern of osteoinductive and osteopromotive and osteoconductive effects.