Que/n-HA/PGCL microspheres orchestrate bone repair via context-dependent osteoimmune mechanisms: a transcriptomic dissection of direct and immune-mediated signaling

IntroductionBone defect repair remains a clinical challenge due to the complex inflammatory microenvironment that regulates mesenchymal stem cell fate.MethodsBased on our previous work demonstrating that quercetin-loaded n-HA/PGCL (Que/n-HA/PGCL) nanocomposite microspheres promote bone repair via immunoregulation and osteogenesis, the present study employs RNA-seq and Western blot validation to elucidate the transcriptomic mechanisms by which these microspheres differentially regulate bone marrow mesenchymal stem cells (BMSCs) in direct versus immune-mediated microenvironments. Using a Transwell co-culture system, we simulated two distinct conditions: direct BMSC-microsphere interaction and BMSC culture with microsphere-modulated RAW264.7 macrophages.ResultsRNA-seq and Western blot analyses revealed context-dependent pathway activation: direct Que/n-HA/PGCL treatment activated PI3K-Akt/MAPK signaling in BMSCs, while immune-mediated conditions activated Ras/MAPK and TGF-β/Smad pathways via macrophage modulation.Discussion and conclusionBy identifying the context-dependent activation of PI3K-Akt/MAPK pathways in direct BMSC interaction and Ras/MAPK/TGF-β/Smad pathways in immune-mediated scenarios, this work offers a mechanistic blueprint for the development of intelligent bone repair materials. The success of bone defect repair is intricately linked to the complex inflammatory microenvironment, which dictates the fate of mesenchymal stem cells.