CRISPR/Cas‑based epigenome editing for osteogenic lineage commitment

Bone regeneration remains constrained by incomplete osteogenic commitment of mesenchymal stem cells (MSCs), underscoring the need for precise lineage control. CRISPR/Cas-based epigenome editing provides programmable access to chromatin regulators without altering the DNA sequence, and catalytically inactive Cas9 (dCas9) fused to transcriptional activators, repressors, or chromatin modifiers enables locus-specific modulation of key osteogenic networks, including RUNX2, OSX, and BMP2, while suppressing inhibitory loci such as PPARG, SOST, and DKK1. Multiplex strategies further allow the concurrent activation of osteogenic genes and repression of adipogenic or Wnt antagonists, reshaping lineage allocation in vitro and in vivo. Delivery innovations-from AAV vectors and lipid nanoparticles to biomaterial scaffolds and extracellular vesicles-support local and systemic applications with increasing precision, while whole-genome chromatin profiling and high-fidelity Cas variants reduce off-target risk, and CRISPRoff/on platforms provide reversible and heritable control of transcriptional states. Proof-of-concept studies in small animals demonstrate bone repair in preclinical models, with emerging large-animal data highlighting translational potential. Remaining challenges include payload size, immunogenicity, durability of epigenetic states, GMP-grade manufacturing, and regulatory classification. Looking ahead, advances such as AI-guided gRNA libraries, mechano-responsive scaffolds, and long-term tracking of epigenetic memory may yield durable "smart" osteo-epigenetic therapies. Collectively, CRISPR/dCas9-based epigenome editing is progressing from mechanistic exploration toward clinically viable strategies for skeletal regeneration.