Objective To investigate the effects of composite nanoparticles E/Ce@MCSNs loaded with epigallocatechin-3-gallate(EGCG)and cerium dioxide(CeO2)on the odonto/osteogenic differentiation of human stem cells from the apical papilla(SCAPs)and macrophage polarization under inflammatory conditions.Methods E/Ce@MCSNs were synthesized and characterized.Cell viabil-ity of SCAPs and RAW 264.7 cells treated with varying concentrations of E/Ce@MCSNs was assessed via CCK-8 assay.The antioxidant enzyme-mimetic activity of E/Ce@MCSNs was evaluated.Under simulated inflammatory conditions,intracellular reactive oxygen species(ROS)scavenging capacity was measured via DCFH-DA fluorescent probe.Alkaline phosphatase(ALP)staining/activity,alizarin red staining/semi-quantitative analysis,and RT-qPCR were performed to detect odonto/osteogenic differentiation markers,in-cluding dentin sialoprotein(DSPP),ALP,runt-related transcription factor 2(Runx-2),type Ⅰ collagen(COL-Ⅰ),and osteopontin(OPN)in SCAPs.The effects of E/Ce@MCSNs on the odontogenic/osteogenic differentiation of SCAPs under this condition were eval-uated.RT-qPCR were used to analyze cytokine expression(TNF-α,IL-1β,IL-6,iNOS,TGF-β,IL-10)and secreted TNF-α/IL-6 levels in RAW264.7 cells.The concentrations of TNF-α and IL-6 in cell cul-ture supernatants were measured by ELISA.Results E/Ce@MCSNs exhibited excellent biocompatibility at concentrations≤100 μg/mL.They demonstrated potent ROS-scavenging activity(P＜0.05)and sig-nificantly enhanced ALP activity(P＜0.001),promoted calcium nodule formation(P＜0.001),and upregulated odonto/osteogenic gene expression(DSPP,ALP,Runx-2,COL-Ⅰ,OPN)in SCAPs under inflammatory conditions(P＜0.05).In RAW264.7 cells,E/Ce@MCSNs downregulated pro-inflammatory cytokines(TNF-α,IL-1 β,IL-6,iNOS)(P＜0.01)and upregulated anti-inflammatory factors(TGF-β,IL-10)(P＜0.001),while reducing TNF-α and IL-6 secretion(P＜0.001).Conclusion E/Ce@MCSNs exert antioxidant and anti-inflammatory effects in apical periodontitis by scavenging excessive ROS,thereby promoting odonto/osteogenic differentiation of SCAPs.

Objective To investigate the effects of composite nanoparticles E/Ce@MCSNs loaded with epigallocatechin-3-gallate(EGCG)and cerium dioxide(CeO2)on the odonto/osteogenic differentiation of human stem cells from the apical papilla(SCAPs)and macrophage polarization under inflammatory conditions.Methods E/Ce@MCSNs were synthesized and characterized.Cell viabil-ity of SCAPs and RAW 264.7 cells treated with varying concentrations of E/Ce@MCSNs was assessed via CCK-8 assay.The antioxidant enzyme-mimetic activity of E/Ce@MCSNs was evaluated.Under simulated inflammatory conditions,intracellular reactive oxygen species(ROS)scavenging capacity was measured via DCFH-DA fluorescent probe.Alkaline phosphatase(ALP)staining/activity,alizarin red staining/semi-quantitative analysis,and RT-qPCR were performed to detect odonto/osteogenic differentiation markers,in-cluding dentin sialoprotein(DSPP),ALP,runt-related transcription factor 2(Runx-2),type Ⅰ collagen(COL-Ⅰ),and osteopontin(OPN)in SCAPs.The effects of E/Ce@MCSNs on the odontogenic/osteogenic differentiation of SCAPs under this condition were eval-uated.RT-qPCR were used to analyze cytokine expression(TNF-α,IL-1β,IL-6,iNOS,TGF-β,IL-10)and secreted TNF-α/IL-6 levels in RAW264.7 cells.The concentrations of TNF-α and IL-6 in cell cul-ture supernatants were measured by ELISA.Results E/Ce@MCSNs exhibited excellent biocompatibility at concentrations≤100 μg/mL.They demonstrated potent ROS-scavenging activity(P＜0.05)and sig-nificantly enhanced ALP activity(P＜0.001),promoted calcium nodule formation(P＜0.001),and upregulated odonto/osteogenic gene expression(DSPP,ALP,Runx-2,COL-Ⅰ,OPN)in SCAPs under inflammatory conditions(P＜0.05).In RAW264.7 cells,E/Ce@MCSNs downregulated pro-inflammatory cytokines(TNF-α,IL-1 β,IL-6,iNOS)(P＜0.01)and upregulated anti-inflammatory factors(TGF-β,IL-10)(P＜0.001),while reducing TNF-α and IL-6 secretion(P＜0.001).Conclusion E/Ce@MCSNs exert antioxidant and anti-inflammatory effects in apical periodontitis by scavenging excessive ROS,thereby promoting odonto/osteogenic differentiation of SCAPs.

Objective To investigate the antibacterial performance and biocompatibility of silver nanoparticles-coated root canal nickel titanium instruments(AgNPs-NiTi).Methods AgNPs-NiTi was prepared using pulse electrochemical deposition.The morphol-ogy of AgNPs-NiTi was observed using field emission scanning electron microscopy(FE-SEM),and the elemental composition and con-tent were analyzed using X-ray diffraction(XRD)and energy dispersive spectroscopy(EDS).The mechanical properties of AgNPs-NiTi were tested.After Co-culturing AgNPs-NiTi with E.faecalis,the antibacterial effect was detected by colony-forming units method.By constructing an in vitro model of E.faecalis biofilm in the root canal of teeth,the antibacterial effect of AgNPs-NiTi was observed using FE-SEM and live/dead bacterial staining.In addition,AgNPs-NiTi was co-cultured with Raw 264.7 cells,and its cytotoxicity was de-tected by CCK-8.Results The pulse electrochemical deposition was used to construct a silver nanoparticle(AgNPs)coating on NiTi instruments with no significant change in the mechanical properties.AgNPs-NiTi significantly inhibited the proliferation of E.faecalis and damaged E.faecalis biofilm in the root canal.AgNPs-NiTi had no significant influence on the proliferation of Raw264.7 cells and had no cytotoxicity.Conclusion The mechanical properties of AgNPs-NiTi are similar to those of nickel titanium instruments.AgNPs-NiTi inhibits E.faecalis proliferation with good biocompatibility.

Via an insufficient coat protein complex I (COPI) retrieval signal, the majority of SARS-CoV-2 spike (S) is resident in host early secretory organelles and a tiny amount is leaked out in cell surface. Only surface-exposed S can be recognized by B cell receptor (BCR) or anti-S therapeutic monoclonal antibodies (mAbs) that is the trigger step for B cell activation after S mRNA vaccination or infected cell clearance by S mAbs. Now, a drug strategy to promote S host surface exposure is absent. Here, we first combined structural and biochemical analysis to characterize S COPI sorting signals. A potent S COPI sorting inhibitor was then invented, evidently capable of promoting S surface exposure and facilitating infected cell clearance by S antibody-dependent cellular cytotoxicity (ADCC). Importantly, with the inhibitor as a probe, we revealed Omicron BA.1 S is less cell surface exposed than prototypes because of a constellation of S folding mutations, possibly corresponding to its ER chaperone association. Our findings not only suggest COPI is a druggable target against COVID-19, but also highlight SARS-CoV-2 evolution mechanism driven by S folding and trafficking mutations.