Lesion-localized hydrogels functionalized with engineered extracellular matrix restore cellular homeostasis by enhancing mitochondrial energy metabolism for osteoarthritis therapy.

[Display omitted] • A biocompatible, injectable, and lesion-localized hydrogel loaded with extracellular matrix (ECM) was developed. • Stimulation of mesenchymal stem cells with TNF-α, IL-6, and IFN-γ enhanced the quality and biological function of the ECM. • The engineered ECM hydrogels effectively maintained chondrocyte homeostasis. • The engineered ECM hydrogels preserved cellular homeostasis by augmenting mitochondrial energy metabolism. • ECM derived from various inflammatory cytokine pre-treatments displayed distinct functional strengths and weaknesses, with IFN-γ-ECM demonstrating superior efficacy. Cartilage damage and degeneration are fundamental pathological features of osteoarthritis (OA), attributed largely to disruptions in chondrocyte homeostasis. Tissue engineering employing functional bioactive materials presents a promising avenue for cartilage regeneration and repair. Particularly, extracellular matrix (ECM) produced by mesenchymal stem cells (MSCs) is gaining traction in the field of tissue engineering and scaffold-based regenerative therapies due to its robust bioactivity and excellent biocompatibility. In this study, we utilized specific inflammatory cytokines associated with OA as stimulators to optimize the MSC-derived secretome. Our in vitro experiments demonstrated that the engineered ECM effectively inhibited early chondrocyte apoptosis, reversed cellular senescence, and maintained anabolic-catabolic equilibrium. Moreover, we developed aldehyde- and methacrylic anhydride-modified hyaluronic acid hydrogels incorporated with ECM (ECM@AH) using photo-cross-linking techniques. The affinity of these ECM-functionalized hydrogels for degraded cartilage was confirmed through in situ cartilage lesion localization experiments in the knee joints of rat OA models. Further in vitro analysis revealed that the engineered ECM@AH, especially IFN-γ-ECM@AH, sustains chondrocyte homeostasis by restoring mitochondrial energy metabolism. Animal studies demonstrated that ECM@AH, localized to cartilage lesions, could reverse cartilage matrix degradation and promote cartilage repair, underscoring the potential of this biomaterial in OA treatment. [ABSTRACT FROM AUTHOR]