CeO@CA-074Me Nanoparticles Alleviate Inflammation and Improve Osteogenic Microenvironment by Regulating the CTSB-NLRP3 Signaling Pathway.

BACKGROUND

It is well established that the interaction between osteogenesis and inflammation can impact bone tissue regeneration. The use of nanoparticles to treat and alleviate inflammation at the molecular level has the potential to improve the osteogenic microenvironment and serve as a therapeutic approach.

METHODS

We have synthesized new hollow cerium oxide nanoparticles and doped with cathepsin B inhibitor (CA-074Me) to create novel CeO@CA-074Me NPs. We characterized the surface morphology and physicochemical properties of CeO@CA-074Me NPs. Macrophage RAW 264.7 was cultured with CeO@CA-074Me NPs using LPS (-LPS) stimulation as a model of inflammation. RT-PCR and Western blot analysis was employed to evaluate the effects of CeO@CA-074Me NPs on macrophage phenotype and the CTSB-NLRP3 signaling pathway. To further investigate the inflammatory osteogenic microenvironment, MC3T3-E1 cells were cultured with -LPS to create an in vitro osteogenic conditions under inflammation. The cells were then co-cultured with CeO@CA-074Me NPs for 7, 14, and 21 d. The osteogenic ability was evaluated using ALP staining, ALP quantitative analysis, alizarin red staining, and RT-PCR analysis.

RESULTS

Findings clearly demonstrated that CeO@CA-074Me NPs could effectively reduce the production of ROS and inhibited CTSB-NLRP3 signal pathway, thereby significantly attenuating the damage caused by the cellular inflammatory response. CeO@CA-074Me NPs could also induce the polarization of macrophages towards anti-inflammatory M2 phenotype. Additionally, results confirmed that CeO@CA-074Me NPs could inhibit inflammation and ameliorate osteogenic microenvironment, thus promoting the osteogenesis of MC3T3-E1 cells.

CONCLUSION

The synthetic CeO@CA-074Me NPs could able to modify the osteogenic microenvironment under inflammatory conditions by simultaneously inhibiting the CTSB-NLRP3 signaling pathway and regulating the macrophage phenotype through their ability to scavenge ROS. Based on these findings, our study may offer a promising approach for managing inflammatory bone damage.