Macrophage lysate-derived cytokine network combined with silk fibroin hydrogel promotes diabetic vascularized bone regeneration

Cell-based therapies are used extensively in tissue engineering because of their great biosafety and diverse biological functions. Among them, macrophage lysate provides a comprehensive and rich network of cytokines to modulate the local immune microenvironment. However, effective strategies for macrophage lysate-based biomaterials with immune-regulatory function are still lacking. In this study, we engineered a silk fibroin hydrogel loaded with THP-1 macrophage whole-cell lysate to regulate the local immune microenvironment and promote vascularized bone regeneration in diabetic bone defects. Specifically, by modulating the expression pattern of key enzyme in energy metabolism (mitochondrial phosphoenolpyruvate carboxykinase, PCK2) of THP-1 cells, we generated a whole-cell lysate enriched with anti-inflammatory factors. This whole-cell lysate facilitated osteogenic differentiation of BMSCs and angiogenesis of HUVECs in vitro, and incorporating this immunomodulatory whole-cell lysate into silk fibroin hydrogel enhanced vascularized bone regeneration in diabetes. Mechanistically, we revealed that PCK2 activated the nuclear factor-kappa B (NF-κB) signaling pathway in THP-1 macrophages by using proteomic profiling. This research provides new insights into the design of cell-derived biomaterials, aiming to improve the therapeutic outcomes of pathological bone defects.