Curcumin-loaded biomimetic nanosponges for osteoarthritis alleviation by synergistically suppressing inflammation and ferroptosis.

• A macrophage membrane coated curcumin-loaded biomimetic nanosponge system was designed for osteoarthritis alleviation. • This system can alleviate the progression of osteoarthritis by synergistically suppressing inflammation and ferroptosis. • We broadened the biomedical application of macrophage membrane as an anti-ferroptosis agent in OA treatment. Osteoarthritis (OA) is a chronic degenerative joint disease characterized by the degradation of articular cartilage while sustained inflammation and ferroptosis have been demonstrated to play crucial roles in the progression of OA. It is an effective strategy to fabricate nanomedicines for OA treatment. However, current research primarily concentrates on anti-inflammation, whereas nanomedicine systems for anti-ferroptosis in OA treatment are rarely reported. Additionally, there are few studies integrating inflammation inhibition with anti-ferroptosis within a single system to ameliorate OA progression. In this study, we introduce a curcumin-loaded biomimetic nanosponge (CM@Cur-NPs) to alleviate OA by synergistically suppressing inflammation and ferroptosis. CM@Cur-NPs were obtained by encapsulating curcumin within polymeric nanoparticles and coating them with macrophage cell membranes. The in vitro and in vivo synergistic anti-inflammatory and anti-ferroptotic effects of CM@Cur-NPs were investigated. It was discovered that the CM@Cur-NPs significantly reduced pro-inflammatory cytokines (TNF-α, IL-6), iNOS, ROS, and apoptosis levels of chondrocytes while concurrently increasing the anti-inflammatory cytokine (IL-4) and extracellular matrix (ECM) content in vitro. We also found that CM@Cur-NPs decreased the expression of the ferroptosis marker Fe2+, ACSL4, and MDA, coupled with an increase in the levels of SLC7A11 and GPX4 of chondrocytes. Lipid peroxidation of chondrocytes was attenuated by CM@Cur-NPs as well. In vivo results indicated that CM@Cur-NPs effectively alleviated OA progression and achieved cartilage protection by upregulating Aggrecan and collagen II expression, along with downregulating ADAMTS5 and MMP13 expression. This study demonstrated that CM@Cur-NPs exhibited enhanced chondroprotective effects through synergistic anti-inflammatory and anti-ferroptotic actions. It is a promising approach to integrate inflammation and ferroptosis inhibition by bioactive nanomaterials for OA treatment. [ABSTRACT FROM AUTHOR]