Hydrous ruthenium oxide triggers template-free and spontaneous growth of metal nanostructures.

Intrinsically conductive ruthenium oxide is an excellent material for energy storage and conversion. Herein, we present hydrous RuO2 (H-RuO2) as a potent reducing agent to achieve spontaneous growth of multiple noble metals at room temperature. Self-assembled gold and platinum, comprising small-sized nanoparticles, are generated on the surface of H-RuO2 without the need for additional templates. Structural analysis reveals that the disordered structure and the presence of oxygen vacancies trigger interfacial redox reactions between H-RuO2 and oxidative metal salts. The resulting integrated nanostructures, consisting of a metal oxide and different metals (H-RuO2@metal), are subsequently used to treat inflammatory bowel diseases. In addition to biomedical applications, our developed synthetic strategy, using reactive oxides to spontaneously generate multicomponent nanostructures, also holds great significance for other catalysis-based applications.

Injectable CNPs/DMP1-loaded self-assembly hydrogel regulating inflammation of dental pulp stem cells for dentin regeneration.

Vital pulp preservation, which is a clinical challenge of aseptic or iatrogenic accidental exposure of the pulp, in cases direct pulp capping is the main technology. Human dental pulp stem cells (hDPSCs) play a critical role in pulp tissue repair, but their differentiative ability could be inhibited by the potential infection and inflammatory response of the exposed pulp. Therefore, inflammatory regulation and differentiated promotion of hDPSCs are both essential for preserving living pulp teeth. In this study, we constructed a functional dental pulp-capping hydrogel by loading cerium oxide nanoparticles (CNPs) and dentin matrix protein-1 (DMP1) into an injectable Fmoc-triphenylalanine hydrogel (Fmoc-phe3 hydrogel) as CNPs/DMP1/Hydrogel for in situ drugs delivery. With a view to long-term storage and release of CNPs (anti-inflammatory and antioxidant) to regulate the local inflammatory environment and DMP1 to promote the regeneration of dentin. Results of CCK-8, LDH release, hemolysis, and Live/Dead assessment of cells demonstrated the good biocompatibility of CNPs/DMP1/Hydrogel. The levels of alkaline phosphatase activity, quantification of the mineralized nodules, expressions of osteogenic genes and proteins demonstrated CNPs/DMP1/Hydrogel could protect the activity of hDPSCs' osteogenic/dentinogenic differentiation by reducing the inflammation response via releasing CNPs. The therapy effects were further confirmed in rat models, CNPs/DMP1/Hydrogel reduced the necrosis rate of damaged pulp and promoted injured pulp repair and reparative dentin formation with preserved vital pulps. In summary, the CNPs/DMP1/Hydrogel composite is an up-and-coming pulp-capping material candidate to induce reparative dentin formation, as well as provide a theoretical and experimental basis for developing pulp-capping materials.

A Glutathione Peroxidase-Mimicking Nanozyme Precisely Alleviates Reactive Oxygen Species and Promotes Periodontal Bone Regeneration.

The use of oxidoreductase nanozymes to regulate reactive oxygen species (ROS) has gradually emerged in periodontology treatments. However, current nanozymes for treating periodontitis eliminate ROS extensively and non-specifically, ignoring the physiological functions of ROS under normal conditions, which may result in uncontrolled side effects. Herein, using the MIL-47(V)-F (MVF) nanozyme, which mimics the function of glutathione peroxidase (GPx), it is proposed that ROS can be properly regulated by specifically eliminating H2 O2 , the most prominent ROS. Through H2 O2 elimination, MVF contributes to limiting inflammation, regulating immune microenvironment, and promoting periodontal regeneration. Moreover, MVF stimulates osteogenic differentiation of periodontal stem cells directly, further promoting regeneration due to the vanadium in MVF. Mechanistically, MVF regulates ROS by activating the nuclear factor erythroid 2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) pathway and promotes osteogenic differentiation directly through the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway. A promising periodontitis therapy strategy is presented using GPx-mimicking nanozymes through their triple effects of antioxidation, immunomodulation, and bone remodeling regulation, making nanozymes an excellent tool for developing precision medicine.

Effect and mechanism of reactive oxygen species-responsive nanoparticles on the regulation of human gingival fibroblast function and inflammation induced by lipopolysaccharide / 口腔疾病防治

Objective@#To investigate the effects of PssL-NAC reactive oxygen species (ROS)-responsive nanoparticles on intracellular ROS production, inflammatory factor levels, collagen production, cell function and Toll-like receptor 4 (TLR4), NF-κB nuclear factor-κB (p65) pathway protein expression in human gingival fibroblasts (HGFs) induced by Porphyromonas gingivalis-lipopolysaccharide (P.g-LPS).@*Methods@#This study was reviewed and approved by the ethics committee. PssL-NAC microspheres containing oil soluble antioxidant N-acetylcysteine (NAC) were obtained by connecting the hydrophobic end of polycaprolactone (PCL) and the hydrophilic end of polyethylene glycol (PEG) via thioketal (TK) bonds in response to ROS, and self loading in the aqueous and oil phases. After preparation of the PssL-NAC microspheres and aqueous NAC solution, successful synthesis of the nanoparticles was verified by transmission electron microscopy. Then, HGFs were exposed to P.g-LPS (0, 5, or 10 μg/mL), P.g-LPS (0, 5, or 10 μg/mL)+NAC, and P.g-LPS (0, 5, or 10 μg/mL)+PssL-NAC, and the ROS levels in the different groups were observed under confocal microscopy to determine the concentration of P.g-LPS for use in subsequent experiments. The groups were as follows: control group (no treatment), P.g-LPS group (HGFs treated with P.g-LPS), NAC group (HGFs treated with P.g-LPS and NAC), and PssL-NAC group (HGFs treated with P.g-LPS and PssL-NAC). Cell counting kit-8 (CCK-8) assays verified the biosafety of PssL-NAC. The ROS levels in the different groups were detected by DCFH-DA probes and observed via confocal microscopy. Real-time qPCR (RT-qPCR) was used to monitor the gene expression levels of the intracellular inflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), collagen 1 (COL1) and collagen 3 (COL3). The effect of PssL-NAC on the migration of HGFs was observed via the scratch test. The protein expression of TLR4-NF-κB, and phosphorylated p65 (p-p65) in the TLR4-NF-κB pathway was evaluated by Western blot.@*Results@#PssL-NAC had no significant effect on HGF proliferation (P>0.05). At elevated P.g-LPS concentrations, PssL-NAC maintained intracellular ROS levels approximately twice those in the control group (P<0.001). PssL-NAC significantly decreased P.g-LPS-induced IL-6 (P<0.001) and TNF-α (P<0.001) gene expression and increased COL1 gene expression (P<0.001). After P.g-LPS stimulation, PssL-NAC restored cell migration to the control level (P>0.05) and decreased the protein expression of TLR4 (P<0.001), p65 (P = 0.006), and p-p65 (P = 0.017) in the TLR4-NF-κB pathway.@*Conclusion@#PssL-NAC maintains the appropriate intracellular ROS concentration, alleviates P.g-LPS-induced inflammation in HGFs through the TLR4-NF-κB pathway, and restores the cell functions of collagen production and migration in an inflammatory environment.

Expert consensus on digital guided therapy for endodontic diseases.

Digital guided therapy (DGT) has been advocated as a contemporary computer-aided technique for treating endodontic diseases in recent decades. The concept of DGT for endodontic diseases is categorized into static guided endodontics (SGE), necessitating a meticulously designed template, and dynamic guided endodontics (DGE), which utilizes an optical triangulation tracking system. Based on cone-beam computed tomography (CBCT) images superimposed with or without oral scan (OS) data, a virtual template is crafted through software and subsequently translated into a 3-dimensional (3D) printing for SGE, while the system guides the drilling path with a real-time navigation in DGE. DGT was reported to resolve a series of challenging endodontic cases, including teeth with pulp obliteration, teeth with anatomical abnormalities, teeth requiring retreatment, posterior teeth needing endodontic microsurgery, and tooth autotransplantation. Case reports and basic researches all demonstrate that DGT stand as a precise, time-saving, and minimally invasive approach in contrast to conventional freehand method. This expert consensus mainly introduces the case selection, general workflow, evaluation, and impact factor of DGT, which could provide an alternative working strategy in endodontic treatment.

Remodeling periodontal osteoimmune microenvironment through MAPK/NFκB phosphorylation pathway of macrophage via intelligent ROS scavenging.

Periodontitis is an inflammatory disorder which leads to the defect of tooth-supporting tissue, especially in alveolar bone. During this process, the polarization behavior of macrophages affects immune inflammation and bone regeneration in which reactive oxygen species (ROS) play an essential role. ROS level should be regulated to the physiological level to protect stem cells from the inflammatory immune microenvironment. Our previous study constructed a ROS-responsive nanoplatform (Pssl-NAC), which possessed ROS-responsive antioxidative effect and could be potentially applied in periodontitis. However, the connection among bone regeneration, inflammation and oxidative stress remained in osteoimmune regulation is not clear. To further investigate the mechanism of the way how Pssl-NAC works in the treatment of periodontitis would be meaningful. Here, we investigated the effect of PssL-NAC in the regulation of the osteoimmune microenvironment through macrophage polarization. Results show PssL-NAC regulated the macrophage polarization direction in an inflammatory environment by maintaining an appropriate level of intracellular ROS, in which the MAPK/NFκB phosphorylation pathway is particularly important. In the macrophage-human periodontal ligament stem cells (hPDLSCs) co-culture system, PssL-NAC treatment significantly enhanced the osteogenic differentiation of hPDLSCs. In vivo experiment further confirmed the M2-like macrophages increased in the periodontal tissue of rats, and the expression of iNOS and p65 decreased after PssL-NAC treatment. In conclusion, PssL-NAC regulates the osteoimmune microenvironment and protects stem cells from oxidative stress injury for bone regeneration, which provides a strategy for the treatment of periodontitis.

Cerium oxide nanoparticles protect against chondrocytes and cartilage explants from oxidative stress via Nrf2/HO-1 pathway in temporomandibular joint osteoarthritis.

Oxidative stress is closely linked to the etiology of temporomandibular joint osteoarthritis. (TMJ-OA) and is an important therapeutic target. Cerium oxide nanoparticles (CNPs) have been broadly studied owing to their powerful antioxidant properties and potential preventive and therapeutic effects against chronic diseases. The current study was designed to explore the protective effects of CNPs on the progression of TMJ-OA and their potential mechanisms. We detected the ability of CNPs to eliminate reactive oxygen species (ROS) in chondrocytes. Moreover, their protective effects on chondrocytes were detected in the level of gene and protein. Furthermore, TUNEL assay, histology and safranin O-fast green staining were used to detect the beneficial effects of CNPs on cartilage explants. The mechanism of CNPs, protecting condylar cartilage by reducing inflammation, was further explored by knocking down the Nuclear factor-erythroid 2-related factor (Nrf2) gene. CNPs could reduce the ROS levels in chondrocytes and cartilage explants and reverse the IL-1ß-induced imbalance of cartilage matrix metabolism and apoptosis. The protective effects of CNPs on cartilage were lost after key antioxidant factors including Nrf2 and heme-oxygenase 1(HO-1) were significantly reduced. In conclusion, this study demonstrated for the first time that activating the Nrf2/HO-1 signaling pathway by CNPs might have therapeutic potential for TMJ-OA.

Combined Black Phosphorus Nanosheets with ICG/aPDT is an Effective Anti-Inflammatory Treatment for Periodontal Disorders.

Introduction: Antibacterial photodynamic treatment (aPDT) has indispensable significance as a means of treating periodontal disorders because of its extraordinary potential for killing pathogenic bacteria by generating an overpowering amount of reactive oxygen species (ROS). The elevated ROS that may result from the antibacterial treatment procedure, however, could exert oxidative pressure inside periodontal pockets, causing irreparable damage to surrounding tissue, an issue that has severely restricted its medicinal applications. Accordingly, herein, we report the use of black phosphorus nanosheets (BPNSs) that can eliminate the side effects of ROS-based aPDT as well as scavenge ROS to produce an antibacterial effect. Methods: The antibacterial effect of ICG/aPDT was observed by direct microscopic colony counting. A microplate reader and confocal microscope enabled measurements of cell viability and the quantification of ROS fluorescence. BPNS administration regulated the oxidative environment. IL-1ß, IL-6, TNF-α, IL-10, TGF-ß, and Arg-1 mRNA expression levels were used to assess the inflammatory response after BPNS treatment. In vivo, the efficacy of the combination of BPNSs and ICG/aPDT was evaluated in rats with periodontal disease by histomorphometric and immunohistochemical analyses. Results: The CFU assay results verified the antibacterial effect of ICG/aPDT treatment, and ROS fluorescence quantification by CLSM indicated the antioxidative ability of the BPNSs. IL-1ß, IL-6, TNF-α, IL-10, TGF-ß, and Arg-1 mRNA expression levels were significantly decreased after BPNS treatment, confirming the in vitro anti-inflammatory effect of this nanomaterial. The histomorphometric and immunohistochemical analyses showed that the levels of proinflammatory factors decreased, suggesting that the BPNSs had anti-inflammatory effects in vivo. Conclusion: Treatment with antioxidative BPNSs gives new insights into future anti-inflammatory therapies for periodontal disease and other infection-related inflammatory illnesses and provides an approach to combat the flaws of aPDT.

High glucose levels contribute to vascular fibrosis via the activation of the endothelial-to-mesenchymal transition in periodontitis.

OBJECTIVE: To determine the changes of Porphyromonas gingivalis (P. gingivalis) growth and metabolism and identify whether the vascular epithelium change could be induced in diabetic periodontitis. BACKGROUND: Maintaining favourable vascular function is a precondition for periodontal regeneration. In diabetic periodontitis, high glucose levels could enhance the metabolism of pathogens, and a complex condition involving inflammation and high glucose levels would disrupt homeostasis of the epithelium and promote fibrosis by endothelial-to-mesenchymal transition (EndMT). METHODS: Porphyromonas gingivalis was cultured with glucose to judge its metabolic activity. Human umbilical vein endothelial cells (HUVECs) were treated with P. gingivalis-lipopolysaccharide (LPS) (10 µg/ml) and/or high glucose concentrations (25 mM), and transforming growth factor (TGF)-ß inhibitor was used to block EndMT. Inflammation level was assessed by flow cytometry. Multiple biological functions including EndMT, angiopoiesis, and cell migration were analysed. Additionally, gene expressions and protein levels were determined with qPCR and western blot, respectively. Finally, blood vessels were cultured ex vivo, and EndMT and fibrosis markers were detected by immunohistochemistry. RESULTS: Glucose could promote P. gingivalis growth and biofilm formation as well as the expression of virulence factor genes including FimA, RgpA, RgpB, and Kgp. P. gingivalis-LPS and glucose could increase intracellular reactive oxygen species (ROS) and promote fibrosis via EndMT in HUVECs, along with attenuating angiopoiesis and cell migration, which could be resumed by blocking EndMT with TGF-ß inhibitor. Vascular fibrosis was observed after the addition of glucose via EndMT regulation. CONCLUSION: Glucose augmented the growth and metabolism of P. gingivalis and promoted fibrosis by the activation of EndMT, as well as the inhibition of angiopoiesis and cell migration.

Introducing Nanozymes: New Horizons in Periodontal and Dental Implant Care.

The prevalence of periodontal and peri-implant diseases has been increasing worldwide and has gained a lot of attention. As multifunctional nanomaterials with enzyme-like activity, nanozymes have earned a place in the biomedical field. In periodontics and implantology, nanozymes have contributed greatly to research on maintaining periodontal health and improving implant success rates. To highlight this progress, we review nanozymes for antimicrobial therapy, anti-inflammatory therapy, tissue regeneration promotion, and synergistic effects in periodontal and peri-implant diseases. The future prospects of nanozymes in periodontology and implantology are also discussed along with challenges.

Erythropoietin induces odontoblastic differentiation of human-derived pulp stem cells via EphB4-Mediated MAPK signaling pathway.

OBJECTIVES: Human-derived pulp stem cells play key roles during dentinogenesis. Erythropoietin is reportedly involved in osteoblastogenesis and facilitates bone formation. However, the mechanism is still unknown. This research was to study the potential of erythropoietin in enhancing odontoblastic differentiation of human-derived pulp stem cells and to determine the underlying mechanism. METHODS: The human-derived pulp stem cells were treated with erythropoietin, EphB4 inhibitor, and MAPK inhibitors, and the odontoblastic differentiation was measured by ALP staining, ALP activity assay, alizarin red S staining, and their quantitative analysis, and RT-qPCR of DSPP, DMP1, OCN, and RUNX2. The direct pulp capping model was established to evaluate the formation of tertiary dentin after treatment with erythropoietin. Western blot assay was conducted to assess relevant protein expressions in the phosphorylated EphB4 and MAPK pathway. RESULTS: The results showed that erythropoietin promoted odontoblastic differentiation of human-derived pulp stem cells at 20 U/ml. Erythropoietin induced tertiary dentin formation in vivo. The potential mechanism of this was upregulating phosphorylated EphB4 and phosphorylated MAPK; furthermore, this effect could be decreased by EphB4 inhibitors, which inhibited MAPK phosphorylation. Blockage of MAPK pathways attenuated human-derived pulp stem cells' odontoblastic differentiation, suggesting that MAPK pathways are involved. CONCLUSION: Erythropoietin induced tertiary dentin formation in vivo. And erythropoietin enhanced human-derived pulp stem cells' odontoblastic differentiation via the EphB4-mediated MAPK signaling pathway.

Estimation of gingival crevicular fluid oxidative stress markers in school-aged children and teenagers with insufficient sleep.

BACKGROUND: Sleep is crucial for survival. Sleep deprivation causes ROS accumulation and, consequently, oxidative stress. The goal of the study was to evaluate gingival crevicular fluid (GCF) levels of the oxidative stress status hydrogen peroxide (H2O2), superoxide glutathione (GSH), and cellular oxidative damage marker malondialdehyde (MDA) in school-aged children and teenagers with insufficient sleep. METHODS: This study investigated sleep duration in 80 participants from two different developmental stages: school-aged children (6-13 years) and teenagers (14-17 years). GCF samples were obtained from all individuals, and samples were investigated to detect H2O2, GSH, and MDA levels using the micro method. RESULTS: Results reveal that GCF MDA and H2O2 in school-age children and teenagers with insufficient sleep were significantly higher than in children with sufficient sleep. GCF GSH with insufficient sleep was insignificantly lower than in children with sufficient sleep. There was no significant difference between school-age and teenage populations. CONCLUSION: Sleep deprivation causes increased levels of oxidative stress in gingival crevicular fluid, and adequate sleep is essential for maintaining redox balance.

A Dopamine-Enabled Universal Assay for Catalase and Catalase-Like Nanozymes.

Developing a universal strategy to measure catalase (CAT)/CAT-like activity, on one hand, overcomes limitations on current assays, such as moderate sensitivity and limited sample scope; on the other hand, facilitates insightful studies on applications of CAT and CAT-like nanozymes. Herein, the oxygen-sensitive and H2O2-inhibitory self-polymerization of dopamine (DA) was demonstrated as an activity indicator of CAT or CAT-like nanozymes, which monitors the catalytically generated O2 in a hypoxic environment. A typical assay for natural CAT was achieved under the optimized conditions. Moreover, this assay was suitable for diverse types of samples, ranging from nanozymes, animal tissues, to human saliva. By comparing the merits and limitations of common methods, this assay shows all-round advantages in sensitivity, specificity, and versatility, facilitating the formulation of measurement criteria and the development of potential standardized assays for CAT (or CAT-like nanozyme) activity.

Cerium oxide nanozyme attenuates periodontal bone destruction by inhibiting the ROS-NFκB pathway.

Periodontitis, an inflammatory disease of oxidative stress, occurs due to excess reactive oxygen species (ROS) contributing to cell and tissue damage which in turn leads to alveolar bone resorption as well as the destruction of other periodontal support tissues. With significant recent advances in nanomaterials, we considered a unique type of nanomaterials possessing enzyme-like characteristics (called nanozymes) for potential future clinical applications, especially in light of the increasing number of studies evaluating nanozymes in the setting of inflammatory diseases. Here, we introduced a therapeutic approach for the management of periodontitis utilizing an injection of cerium oxide nanoparticles (CeO2 NPs) in situ. In this study, our synthesized CeO2 NPs could act as ROS scavengers in the inflammatory microenvironment with ideal outcomes. In vitro and in vivo experiments provide strong evidence on the roles of CeO2 NPs in scavenging multiple ROS and suppressing ROS-induced inflammation reactions stimulated by lipopolysaccharides. Moreover, CeO2 NPs could inhibit the MAPK-NFκB signalling pathway to suppress inflammatory factors. In addition, the results from a rat periodontitis model demonstrate that CeO2 NPs could exhibit a remarkable capacity to attenuate alveolar bone resorption, decrease the osteoclast activity and inflammation, and consequently improve the restoration of destroyed tissues. Collectively, our present study underscores the potential of CeO2 NPs for application in the treatment of periodontitis, and provides valuable insights into the application of nanozymes in inflammatory diseases.

Transcriptome analysis of Fusobacterium nucleatum reveals differential gene expression patterns in the biofilm versus planktonic cells.

As a chronic infectious disease, periodontitis can cause gum recession, loss of alveolar bone, loosening of teeth, and even loss of teeth. Dental plaque biofilm is the initiating factor for the occurrence and development of periodontitis. Fusobacterium nucleatum (F. nucleatum) plays a vital role in the structure and ecology of dental plaque biofilms. It is a bridge between early and late colonization bacteria in dental plaque. Understanding the molecular mechanism of F. nucleatum during biofilm development is essential to control periodontitis. This study aimed to determine gene expression profiles of the F. nucleatum strain, ATCC 25586, in the planktonic and biofilm phase through RNA-sequencing approach. The results were confirmed by quantitative reverse transcriptase PCR (RT-qPCR). The results clearly illustrate the difference in gene expression of F. nucleatum under planktonic and biofilms. A total of 110 genes were differentially expressed by F. nucleatum in the biofilm state compared with the planktonic state. The 25 upregulated genes in the biofilm state were mainly related to carbohydrate and amino acid metabolism, while the 85 downregulated genes were primarily associated with cell growth, division, and oxidative stress; most of the upregulated genes of F. nucleatum involved in virulence and oral malodor. Furthermore, the transcriptome analysis and antibacterial activity test also identified Lysine might exhibit the antibacterial and antibiofilm activity of F. nucleatum for the first time. These new findings could provide caveats for future studies on the regulation and maintenance of plaque biofilm and the development of biomarkers for periodontitis.

Robust intervention for oxidative stress-induced injury in periodontitis via controllably released nanoparticles that regulate the ROS-PINK1-Parkin pathway.

Oxidative stress in periodontitis has emerged as one of the greatest barriers to periodontal tissue restoration. In this study, we synthesized controlled drug release nanoparticles (MitoQ@PssL NPs) by encasing mitoquinone (MitoQ; an autophagy enhancer) into tailor-made reactive oxygen species (ROS)-cleavable amphiphilic polymer nanoparticles (PssL NPs) to regulate the periodontitis microenvironment. Once exposed to reactive oxygen species, which were substantially overproduced under oxidative stress conditions, the ROS-cleavable PssL was disintegrated, promoting the release of the encapsulated MitoQ. The released mitoquinone efficiently induced mitophagy through the PINK1-Parkin pathway and successfully reduced oxidative stress by decreasing the amount of reactive oxygen species. With the gradual decrease in the reactive oxygen species level, which was insufficient to disintegrate PssL, the release of mitoquinone was reduced and eventually eliminated, which contributed to a redox homeostasis condition and facilitated the regeneration of periodontal tissue. MitoQ@PssL NPs have great potential in the treatment of periodontitis via microenvironment-controlled drug release, which will provide a new avenue for periodontal regeneration and diseases related to imbalanced redox metabolism.