Modulation of SEMA4D-modified titanium surface on M2 macrophage polarization via activation of Rho/ROCK-mediated lactate release of endothelial cells: In vitro and in vivo.

SEMA4D-modified titanium surfaces can indirectly regulate macrophages through endothelial cells to achieve an anti-inflammatory effect, which is beneficial for healing soft tissues around the gingival abutment. However, the mechanism of surface-induced cellular phenotypic changes in SEMA4D-modified titanium has not yet been elucidated. SEMA4D activates the RhoA signaling pathway in endothelial cells, which coordinates metabolism and cytoskeletal remodeling. This study hypothesized that endothelial cells inoculated on SEMA4D-modified titanium surfaces can direct M2 polarization of macrophages via metabolites. An indirect co-culture model of endothelial cells and macrophages was constructed in vitro, and specific inhibitors were employed. Subsequently, endothelial cell adhesion and migration, metabolic changes, Rho/ROCK1 expression, and inflammatory expression of macrophages were assessed via immunofluorescence microscopy, specific kits, qRT-PCR, and Western blotting. Moreover, an in vivo rat bilateral maxillary implant model was constructed to evaluate the soft tissue healing effect. The in vitro experiments showed that the SEMA4D group had stronger endothelial cell adhesion and migration, increased Rho/ROCK1 expression, and enhanced release of lactate. Additionally, decreased macrophage inflammatory expression was observed. In contrast, the inhibitor group partially suppressed lactate metabolism and motility, whereas increased inflammatory expression. The in vivo analyses indicated that the SEMA4D group had faster and better angiogenic and anti-inflammatory effects, especially in the early stage. In conclusion, via the Rho/ROCK1 signaling pathway, the SEMA4D-modified titanium surface promotes endothelial cell adhesion and migration and lactic acid release, then the paracrine lactic acid promotes the polarization of macrophages to M2, thus obtaining the dual effects of angiogenesis and anti-inflammation.

Osteogenic and anti-inflammatory effects of SLA titanium substrates doped with chitosan-stabilized selenium nanoparticles via a covalent coupling strategy.

Osseointegration is a prerequisite for the function of dental implants, and macrophage-dominated immune responses triggered by implantation determine the outcome of ultimate bone healing mediated by osteogenic cells. The present study aimed to develop a modified titanium (Ti) surface by covalently immobilizing chitosan-stabilized selenium nanoparticles (CS-SeNPs) to sandblasted, large grit, and acid-etched (SLA) Ti substrates and further explore its surface characteristics as well as osteogenic and anti-inflammatory activities in vitro. CS-SeNPs were successfully prepared by chemical synthesis and characterized their morphology, elemental composition, particle size, and Zeta potential. Subsequently, three different concentrations of CS-SeNPs were loaded to SLA Ti substrates (Ti-Se1, Ti-Se5, and Ti-Se10) using a covalent coupling strategy, and the SLA Ti surface (Ti-SLA) was used as a control. Scanning electron microscopy images revealed different amounts of CS-SeNPs, and the roughness and wettability of Ti surfaces were less susceptible to Ti substrate pretreatment and CS-SeNP immobilization. Besides, X-ray photoelectron spectroscopy analysis showed that CS-SeNPs were successfully anchored to Ti surfaces. The results of in vitro study showed that the four as-prepared Ti surfaces exhibited good biocompatibility, with Ti-Se1 and Ti-Se5 groups showing enhanced adhesion and differentiation of MC3T3-E1 cells compared with the Ti-SLA group. In addition, Ti-Se1, Ti-Se5, and Ti-Se10 surfaces modulated the secretion of pro-/anti-inflammatory cytokines by inhibiting the nuclear factor kappa B pathway in Raw 264.7 cells. In conclusion, doping SLA Ti substrates with a modest amount of CS-SeNPs (1-5 mM) may be a promising strategy to improve the osteogenic and anti-inflammatory activities of Ti implants.

Antibacterial and Fluorescence Staining Properties of an Innovative GTR Membrane Containing 45S5BGs and AIE Molecules In Vitro.

This study aimed to add two functional components-antibacterial 45S5BGs particles and AIE nanoparticles (TPE-NIM+) with bioprobe characteristics-to the guided tissue regeneration (GTR) membrane, to optimize the performance. The PLGA/BG/TPE-NIM+ membrane was synthesized. The static water contact angle, morphologies, and surface element analysis of the membrane were then characterized. In vitro biocompatibility was tested with MC3T3-E1 cells using CCK-8 assay, and antibacterial property was evaluated with Streptococcus mutans and Porphyromonas gingivalis by the LIVE/DEAD bacterial staining and dilution plating procedure. The fluorescence staining of bacteria was observed by Laser Scanning Confocal Microscope. The results showed that the average water contact angle was 46°. In the cytotoxicity test, except for the positive control group, there was no significant difference among the groups (p > 0.05). The antibacterial effect in the PLGA/BG/TPE-NIM+ group was significantly (p < 0.01), while the sterilization rate was 99.99%, better than that in the PLGA/BG group (98.62%) (p < 0.01). Confocal images showed that the membrane efficiently distinguished G+ bacteria from G- bacteria. This study demonstrated that the PLGA/BG/TPE-NIM+ membrane showed good biocompatibility, efficient sterilization performance, and surface mineralization ability and could be used to detect pathogens in a simple, fast, and wash-free protocol.

Dietary citrate supplementation enhances longevity, metabolic health, and memory performance through promoting ketogenesis.

Citrate is an essential substrate for energy metabolism that plays critical roles in regulating cell growth and survival. However, the action of citrate in regulating metabolism, cognition, and aging at the organismal level remains poorly understood. Here, we report that dietary supplementation with citrate significantly reduces energy status and extends lifespan in Drosophila melanogaster. Our genetic studies in fruit flies implicate a molecular mechanism associated with AMP-activated protein kinase (AMPK), target of rapamycin (TOR), and ketogenesis. Mice fed a high-fat diet that supplemented with citrate or the ketone body ß-hydroxybutyrate (ßOHB) also display improved metabolic health and memory. These results suggest that dietary citrate supplementation may prove to be a useful intervention in the future treatment of age-related dysfunction.