Purpose: Ischemic stroke is a high-incidence disease that threatens human well-being. The potent neuroprotective effects render reactive oxygen species (ROS) scavengers potential agents for acute ischemic stroke therapy. Challenges such as inadequate permeability across the blood-brain barrier (BBB), limited half-life, and adverse effects hinder the widespread utilization of small molecule and inorganic ROS scavengers. Thus, there is an urgent demand for efficacious neuroprotective agents targeting ischemic stroke. Our study discovered the superoxide dismutase (SOD)-mimetic activity of recombinant human heavy chain ferritin (rHF) nanoparticles expressed from Escherichia coli (E. coli). Subsequent investigations delved into the ROS-scavenging proficiency of rHF within neural cells, its therapeutic efficacy against ischemic stroke, and the elucidation of its neuroprotective mechanisms.
Methods: rHF protein nanoparticles were expressed in E. coli and purified via size-exclusion chromatography. The superoxide anion (•O₂⁻) scavenging SOD-mimetic activity of rHF nanoparticles was measured using a SOD detection kit. The ROS scavenging ability and protection effects against oxidative damage of rHF nanoparticles were studied in H₂O₂-induced PC12 cells. Therapeutic effects and neuroprotective mechanisms of rHF against ischemic stroke were investigated with transient middle cerebral artery occlusion (MCAO) reperfusion mice model.
Results: rHF nanoparticles can eliminate excessive ROS in nerve cells and alleviate oxidative damage. The results of animal experiments demonstrated that rHF nanoparticles passed across BBB, reduced infarct areas in brain tissue, and lowered the neurological deficit score of ischemia-reperfusion model mice. Additionally, rHF nanoparticles mitigated neuronal apoptosis and ferroptosis, suppressed microglial activation, maintained oxygen homeostasis, and exhibited negligible organ toxicity.
Conclusion: rHF nanoparticle could be developed as a new ROS scavenger for nerve cells and has therapeutic potential as a drug for cerebral ischemia-reperfusion injury.

Keywords: human heavy chain ferritin, ROS scavenger, ischemic stroke, SOD-mimetic, neuroprotection