Elastin-associated epigenetic regulation of ROCK1/Wnt/β-catenin signaling promotes BMSC osteogenesis and cranial bone regeneration

Osteoporosis is a prevalent metabolic bone disorder characterized by progressive bone loss and increased fragility. The elastin gene (ELN), which encodes the extracellular matrix protein elastin, has emerged as a potential regulator of bone marrow-derived mesenchymal stem cell (BMSC) osteogenic differentiation and bone regeneration. However, the regulatory mechanism remains incompletely understood. To elucidate the role of ELN, single-cell transcriptomic analyses were conducted to screen for osteogenesis-associated regulators during BMSCs differentiation. The epigenetic function of ELN was assessed through chromatin remodeling and pathway activation analyses. A functionalized silk fibroin (SF) hydrogel incorporating ELN peptides was designed and evaluated in vitro for osteogenic induction and in vivo using an osteoporosis-related cranial defect model. ELN expression increased during osteogenic differentiation, accompanied by enhanced nuclear enrichment of elastin protein. Mechanistically, ELN-associated chromatin enrichment at ROCK1 regulatory regions was accompanied by increased ROCK1 expression and activation of Wnt/β-catenin signaling, thereby promoting osteogenic differentiation. The ELN-functionalized SF hydrogel demonstrated excellent biocompatibility, promoted osteogenic differentiation of BMSCs in vitro, and effectively repaired cranial defects in vivo. This study reveals ELN as a pivotal epigenetic regulator of BMSCs osteogenesis, acting through the ROCK1/Wnt/β-catenin axis. Incorporation of ELN peptides into a silk fibroin hydrogel provides a novel biomaterial-based strategy for enhancing bone regeneration, particularly under osteoporotic conditions.