MicroRNA expression profile of human periodontal ligament cells under the influence of Porphyromonas gingivalis LPS.

Periodontitis is a chronic inflammatory disease which is caused by bacterial infection and leads to the destruction of periodontal tissues and resorption of alveolar bone. Thus, special attention should be paid to the mechanism under lipopolysaccharide (LPS)-induced periodontitis because LPS is the major cause of periodontitis. However, to date, miRNA expression in the LPS-induced periodontitis has not been well characterized. In this study, we investigated miRNA expression patterns in LPS-treated periodontal ligament cells (PDLCs). Through miRNA array and differential analysis, 22 up-regulated miRNAs and 28 down-regulated miRNAs in LPS-treated PDLCs were identified. Seven randomly selected up-regulated (miR-21-5p, 498, 548a-5p) and down-regulated (miR-495-3p, 539-5p, 34c-3p and 7a-2-3p) miRNAs were examined by qRT-PCR, and the results proved the accuracy of the miRNA array. Moreover, targets of these deregulated miRNAs were analysed using the miRWalk database. Database for Annotation, Visualization and Integration Discovery software were performed to analyse the Gene Ontology and Kyoto Encyclopaedia of Genes and Genomes pathway of differential expression miRNAs, and the results shown that Toll-like receptor signalling pathway, cAMP signalling pathway, transforming growth factor-beta signalling pathway, mitogen-activated protein kinase (MAPK) signalling pathway and other pathways were involved in the molecular mechanisms underlying LPS-induced periodontitis. In conclusion, this study provides clues for enhancing our understanding of the mechanisms and roles of miRNAs as key regulators of LPS-induced periodontitis.

Electrical Stimulations Generated by P(VDF-TrFE) Films Enhance Adhesion Forces and Odontogenic Differentiation of Dental Pulp Stem Cells (DPSCs).

Biophysical and biochemical cues of biomaterials can regulate cell behaviors. Dental pulp stem cells (DPSCs) in pulp tissues can differentiate to odontoblast-like cells and secrete reparative dentin to form a barrier to protect the underlying pulp tissues and enable complete pulp healing. Promotion of the odontogenic differentiation of DPSCs is essential for dentin regeneration. The effects of the surface potentials of biomaterials on the adhesion and odontogenic differentiation of DPSCs remain unclear. Here, poly(vinylidene fluoride-trifluoro ethylene) (P(VDF-TrFE)) films with different surface potentials were prepared by the spin-coating technique and the contact poling method. The cytoskeletal organization of DPSCs grown on P(VDF-TrFE) films was studied by immunofluorescence staining. Using atomic force microscopy (AFM), the lateral detachment forces of DPSCs from P(VDF-TrFE) films were quantified. The effects of electrical stimulation generated from P(VDF-TrFE) films on odontogenic differentiation of DPSCs were evaluated in vitro and in vivo. The unpolarized, positively polarized, and negatively polarized films had surface potentials of -52.9, +902.4, and -502.2 mV, respectively. DPSCs on both negatively and positively polarized P(VDF-TrFE) films had larger cell areas and length-to-width ratios than those on the unpolarized films (P < 0.05). During the detachment of DPSCs from P(VDF-TrFE) films, the average magnitudes of the maximum detachment forces were 29.4, 72.1, and 53.9 nN for unpolarized, positively polarized, and negatively polarized groups, respectively (P < 0.05). The polarized films enhanced the mineralization activities and increased the expression levels of the odontogenic-related proteins of DPSCs compared to the unpolarized films (P < 0.05). The extracellular signal-regulated kinase (ERK) signaling pathway was involved in the odontogenic differentiation of DPSCs as induced by surface charge. In vivo, the polarized P(VDF-TrFE) films enhanced adhesion of DPSCs and promoted the odontogenic differentiation of DPSCs by electrical stimulation, demonstrating a potential application of electroactive biomaterials for reparative dentin formation in direct pulp capping.

Enhancing Effects of Immobilized Chondroitin Sulfate on Odontogenic Differentiation of Dental Pulp Stem Cells and Reparative Dentin Formation.

INTRODUCTION: Chondroitin sulfate (CS) is a major proteoglycan involved in the mineralization of the organic matrix of dentin. In this study, the roles of CS immobilized in cross-linked collagen I (Col I) hydrogels on odontogenic differentiation of dental pulp stem cells (DPSCs) and reparative dentin formation were investigated. METHODS: Different concentrations of CS were incorporated into the genipin-cross-linked Col I hydrogels (CS-0.05, CS-0.1, and CS-0.2, respectively). The influences of CS on the proliferation and odontogenic differentiation of DPSCs were investigated. Finally, the effect of the functionalized hydrogel on the formation of reparative dentin was analyzed in a rat pulp capping model in vivo. RESULTS: CS improved the proliferation of DPSCs seeded on the hydrogels (P < .05). CS also enhanced the mineralization activities and increased the expression levels of the odontogenic-related proteins of DPSCs on days 7 and 14 (P < .05). In vivo, CS-0.1 hydrogel induced reparative dentin formation with higher quality compared with mineral trioxide aggregate. CONCLUSIONS: CS immobilized in Col I hydrogels could induce odontogenic differentiation of DPSCs in vitro and promote homogeneous mineralized barrier formation in vivo. CS-Col I hydrogel has the potential for reparative dentin formation of high quality in direct pulp capping.

Exosomes derived from dental pulp stem cells accelerate cutaneous wound healing by enhancing angiogenesis via the Cdc42/p38 MAPK pathway.

Skin wound healing is a common challenging clinical issue which requires advanced treatment strategies. The present study investigated the therapeutic effects of exosomes derived from dental pulp stem cells (DPSC­Exos) on cutaneous wound healing and the underlying mechanisms. The effects of DPSC­Exos on cutaneous wound healing in mice were examined by measuring wound closure rates, and using histological and immunohistochemical analysis. A series of functional assays were performed to evaluate the effects of DPSC­Exos on the angiogenic activities of human umbilical vein endothelial cells (HUVECs) in vitro. Tandem mass tag­based quantitative proteomics analysis of DPSCs and DPSC­Exos was performed. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were used to evaluate the biological functions and pathways for the differentially expressed proteins in DPSC­Exos. Western blot analysis was used to assess the protein levels of cell division control protein 42 (Cdc42) and p38 in DPSC­Exos and in HUVECs subjected to DPSC­Exos­induced angiogenesis. SB203580, a p38 mitogen­activated protein kinase (MAPK) signaling pathway inhibitor, was employed to verify the role of the p38 MAPK pathway in vitro and in vivo. Histological and immunohistochemical staining revealed that the DPSC­Exos accelerated wound healing by promoting neovascularization. The DPSC­Exos promoted the migration, proliferation and capillary formation capacity of HUVECs. Proteomics data demonstrated that proteins contained in DPSC­Exos regulated vasculature development and angiogenesis. Pathway analysis revealed that proteins expressed in DPSC­Exos were involved in several pathways, including MAPK pathway. Western blot analysis demonstrated that the DPSC­Exos increased the protein levels of Cdc42 and phosphorylation of p38 in HUVECs. SB203580 suppressed the angiogenesis induced by DPSC­Exos. On the whole, the present study demonstrates that DPSC­Exos accelerate cutaneous wound healing by enhancing the angiogenic properties of HUVECs via the Cdc42/p38 MAPK signaling pathway.

Nanoengineered Neutrophils as a Cellular Sonosensitizer for Visual Sonodynamic Therapy of Malignant Tumors.

The rapid evolution of cell-based theranostics has attracted extensive attention due to their unique advantages in biomedical applications. However, the inherent functions of cells alone cannot meet the needs of malignant tumor treatment. Thus endowing original cells with new characteristics to generate multifunctional living cells may hold a tremendous promise. Here, the nanoengineering method is used to combine customized liposomes with neutrophils, generating oxygen-carrying sonosensitizer cells with acoustic functions, which are called Acouscyte/O2 , for the visual diagnosis and treatment of cancer. Specifically, oxygen-carried perfluorocarbon and temoporfin are encapsulated into cRGD peptide modified multilayer liposomes (C-ML/HPT/O2 ), which are then loaded into live neutrophils to obtain Acouscyte/O2 . Acouscyte/O2 can not only carry a large amount of oxygen but also exhibits the ability of long circulation, inflammation-triggered recruitment, and decomposition. Importantly, Acouscyte/O2 can be selectively accumulated in tumors, effectively enhancing tumor oxygen levels, and triggering anticancer sonodynamics in response to ultrasound stimulation, leading to complete obliteration of tumors and efficient extension of the survival time of tumor-bearing mice with minimal systemic adverse effects. Meanwhile, the tumors can be monitored in real time by temoporfin-mediated fluorescence imaging and perfluorocarbon (PFC)-microbubble-enhanced ultrasound imaging. Therefore, the nanoengineered neutrophils, i.e., Acouscyte/O2 , are a new type of multifunctional cellular drug, which provides a new platform for the diagnosis and sonodynamic therapy of solid malignant tumors.

Nanoscale chemical and mechanical heterogeneity of human dentin characterized by AFM-IR and bimodal AFM.

Human dentin, as an important calcified tissue in the body, plays significant roles in withstanding masticatory forces and has a complex hierarchical organization. Understanding the composition and ultrastructure of dentin is critical for elucidating mechanisms of biomineralization under healthy and pathological states. Here, atomic force microscope infrared spectroscopy (AFM-IR) and AFM-based amplitude modulation-frequency modulation (AM-FM) techniques were utilized to detect the heterogeneity in chemical composition and mechanical properties between peritubular and intertubular dentin at the nanoscale. AFM-IR spectra collected from peritubular and intertubular dentin contained similar vibrational bands in the amide regions (I, II and III), suggesting that collagen may exist in both structures. A distinctive band at 1336 cm-1 indicative of S[bond, double bond]O stretching vibrations was detected only in peritubular dentin. AFM-IR imaging showed an uneven distribution of chemical components at different locations, confirming the heterogeneity of dentin. The Young's modulus of peritubular dentin was higher, and was associated to a higher mineral content. This study demonstrated distinctive chemical and mechanical properties of peritubular dentin, implying the different development and mineralization processes between peritubular and intertubular dentin. AFM-IR is useful to provide compositional information on the heterogeneity of human dentin, helping to understand the mineral deposition mechanisms of dentin.

Customized Borosilicate Bioglass Scaffolds With Excellent Biodegradation and Osteogenesis for Mandible Reconstruction.

Graft reconstruction of the mandible is an important approach that aims at improving the appearance and functionality of defected mandibles. The traditional implant materials are generally bioinert, non-degradable, and that they lack favorable pore structures for cell proliferation, which limit their clinical application. In this study, we used boron-containing bioactive glass which was combined with a three-dimensional (3D) printing technology to construct an osteoinductive implant scaffold, according to the imaging instructions of CT scan on bone defects. Here, the boron-containing bioglass scaffold (B-BGs) was prepared through sol-gel processing and a 3D print technique. Different boron content of borosilicate bioglass was prepared by incorporating B2O3 (molar: 19.4 and 38.8%) into 58S bioglass to replace parts of SiO2. For fabricated mandible implants through three-dimensional 3D printing of B-BGs (size: 8 × 2 mm; pore size: 250 µm) modified with borosilicate bioglass powder and sodium alginate. Notably, the compressive strength of the B-BGs was about 3.8 Mpa, which supported mandibular activity. Subsequently, the excellent biocompatibility of B-BGs was confirmed using cytotoxicity in vitro studies. Finally, data from in vivo experiments demonstrated that the B-BGs could promote bone regeneration and they could almost get completely degraded within 4 weeks. Our results showed that the boron-containing bioglass could repair mandibular defects.

L-cysteine modified ZnO: Small change while great progress.

ZnO as an important nanomaterial have been widely used in biomedical fields, however, ZnO has noticeable damage to the organs such as lung and liver, from the long run, its biosafety still needs improvements. In this work, we proposed a simple method to modify the surface of ZnO with l-cysteine. The basic characterizations showed that the surface modification can greatly affect its self-assembly and optical properties. Furthermore, the surface modification can greatly improve its biocompatibility and without change of its bulk antibacterial properties. Moreover, compared with ZnO, the l-cysteine modified ZnO showed much better biosafety in the in vivo test, demonstrating that the modified ZnO may have perspective applications in biomedical fields.

Blue-Light -Activated Nano-TiO2@PDA for Highly Effective and Nondestructive Tooth Whitening.

The application of polydopamine (PDA)-modified titanium dioxide nanoparticles (nano-TiO2@PDA) as a new blue-light-activated tooth whitening material was discussed for the first time. Compared with the classical clinical whitening agent (peroxide, hydrogen peroxide, and carbamide peroxide), nano-TiO2@PDA-based treatment not only had a similar whitening effect but also showed remarkably less damage on the enamel structure. Essentially, a highly effective and nondestructive tooth whitening treatment could thus be realized accordingly. The toxicity and antibacterial properties of this material were also evaluated systematically.