ROS-responsive 3D biological scaffold delivers hypoxia-primed extracellular vesicles for targeted modulation of neuroinflammation in intracerebral hemorrhage.

BACKGROUND: Emerging evidence suggests that paracrine mechanisms may underlie the therapeutic effects of human umbilical cord mesenchymal stem cell-derived extracellular vesicles (EVs) (hUCMSC-exos) in mitigating neuroinflammation following intracerebral hemorrhage (ICH). Hypoxic preconditioning enhances the paracrine efficacy of hUCMSC-exos. Building on prior studies [1, 2], we developed a ROS-responsive three-dimensional (3D) biological scaffold encapsulating hypoxia-primed EVs (Hypo-Exos) for sustained release under reactive oxygen species (ROS)-rich conditions. METHODS: The 3D biological scaffold was fabricated via a thermoresponsive crosslinking strategy using gelatin methacrylate (GelMA), silk fibroin, and brain-derived decellularized extracellular matrix (dECM), functionalized with phenylboronic acid (PBA)-modified polyvinyl alcohol (PVA). Hypo-Exos, enriched with miR-146b via hypoxia-inducible factor-1α (HIF-1α) activation, were incorporated into the scaffold using advanced 3D bioprinting. Dual-luciferase reporter assays validated miR-146b targeting of the 3'UTR of COP1 (an E3 ubiquitin ligase). In a rat ICH model, the scaffold was implanted in situ. Neurological function, angiogenesis, neuroinflammation, and synaptic plasticity were evaluated at days 1, 4, 7, and 14. RESULTS: The 3D biological scaffold enabled sustained delivery of Hypo-Exos, shifting microglial polarization from pro-inflammatory M1 to anti-inflammatory M2 phenotypes, thereby attenuating neuroinflammation and neuronal damage. Mechanistically, miR-146b suppressed COP1 expression via post-transcriptional silencing, thereby attenuating NF-κB p65 signaling and downregulating pro-inflammatory cytokines. CONCLUSION: The ROS-responsive 3D biological scaffold -mediated delivery of Hypo-Exos modulates neuroinflammation through ubiquitination pathways, stabilizes the early-phase ICH microenvironment, and improves functional recovery. This platform represents a promising therapeutic strategy for ICH, offering dual advantages as a drug delivery system and a regenerative therapy.