Ability of SPP1 to Alleviate Post-Intracerebral Hemorrhage Ferroptosis via Nrf2/HO1 Pathway.

PURPOSE: This study aimed to investigate the role of secretory phosphoprotein 1 (SPP1/OPN) in modulating iron-induced cell death (ferroptosis) following intracerebral hemorrhage (ICH). By integrating transcriptomic analysis and experimental validation, we sought to identify key molecular pathways and therapeutic targets associated with ferroptosis in ICH. METHOD: The Gene Expression Omnibus Series GSE24265 dataset was analyzed using the limma package (R platform) to identify differentially expressed genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) enrichment analyses were performed to elucidate biological functions. Genes associated with iron-induced mortality were identified by cross-referencing transcriptomic profiles with the FerrDb database. A protein-protein interaction network was constructed using Cytoscape, and hub genes were identified. An experimental ICH model was developed in mice using stereotactic instrumentation, and the effects of OPN administration were evaluated through neurological assessments, biochemical assays (superoxide dismutase, glutathione, malondialdehyde), Western immunoblotting (GPX4, ACSL4), Prussian blue histochemistry, and electron microscopy. FINDING: Transcriptomic analysis identified 27 hub genes, with CD44 and ITGB3 characterized as receptors for OPN. In the ICH model, OPN administration improved neurological outcomes, elevated antioxidant markers, and reduced lipid peroxidation. OPN upregulated GPX4 while suppressing ACSL4, indicating anti-ferroptotic effects. These protective effects were mediated through the Nrf2 pathway, as confirmed by inhibitor ML385. Prussian blue staining and electron microscopy demonstrated reduced cerebral iron deposition and mitochondrial damage following OPN treatment. CONCLUSION: This study provides novel evidence for SPP1/OPN as a key modulator of ferroptosis in ICH, highlighting its potential as a therapeutic target. By enhancing iron homeostasis and mitigating oxidative stress, OPN offers a promising strategy for improving outcomes in ICH patients.