NCOA4を介したフェロプトーシスは、放射線皮膚炎におけるcGAS-STING依存性の炎症を駆動する：Cu-ATSMによる保護的調節

Radiation dermatitis (RD) remains a major clinical complication of radiotherapy, but its upstream molecular mechanisms are incompletely understood. Increasing evidence suggests that ferroptosis-an iron-dependent form of regulated cell death-may contribute to radiation-induced tissue injury, yet its role in skin pathology and immune activation remains undefined.

We integrated multi-omics analysis, cellular co-culture, computational modeling, and in vivo validation to investigate the role of NCOA4-mediated ferritinophagy and its interplay with the cGAS-STING pathway in RD. Bulk and single-cell RNA-seq analyses were used to characterize ferroptosis-related transcriptional signatures. Biochemical assays, transmission electron microscopy, and cytokine profiling evaluated ferroptosis and inflammation in irradiated keratinocytes and macrophages. The redox-active compound Cu-ATSM was tested as a potential therapeutic modulator both in vitro and in a mouse RD model.

Ionizing radiation (IR) induced NCOA4 upregulation and ferritin degradation in epidermal keratinocytes, leading to labile iron accumulation, lipid peroxidation, and activation of ferroptotic markers such as ACSL4. Co-culture experiments demonstrated that ferroptotic keratinocytes released DNA-associated DAMPs that activated the cGAS-STING-IFN-β axis in macrophages, forming a redox-immune feedback loop. Cu-ATSM treatment markedly suppressed ferroptosis and downstream STING activation. Docking and molecular dynamics simulations positioned Cu-ATSM within the FTH1-binding interface of NCOA4, suggesting competitive inhibition, while immunoprecipitation-MRM mass spectrometry confirmed physical association. In vivo, topical Cu-ATSM significantly ameliorated RD severity, preserved mitochondrial morphology, and reduced ferroptosis and inflammatory cytokine expression in irradiated skin.

These findings identify the NCOA4-ferroptosis-cGAS-STING axis as a key pathogenic pathway linking redox imbalance to inflammation in radiation dermatitis. Cu-ATSM acts as a multimodal modulator that interferes with NCOA4-mediated ferritinophagy and mitigates ferroptosis-driven immune activation. This study establishes a mechanistic framework for ferroptosis-targeted interventions and supports Cu-ATSM as a promising therapeutic strategy for mitigating radiation-induced skin injury.