Ferritin in ferroptosis: Implications for neurodegenerative diseases (Review).

Neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis, are characterized by progressive loss of neurons. Although the precise pathogenesis of such diseases is complex and multifactorial, several molecular pathways have been implicated, including the aggregation of misfolded proteins, mitochondrial dysfunction, oxidative stress, neuroinflammation and disrupted iron homeostasis. Emerging evidence has underscored the pivotal role of ferroptosis, an iron‑dependent, non‑apoptotic form of cell death, in neurodegenerative disease progression. Ferritin, characterized by a 24‑subunit hollow sphere structure composed of heavy and light chains, plays a key role in the network regulating cerebral iron homeostasis. In response to cellular iron overload, ferritin expression is upregulated to sequester labile iron and mitigate Fenton reaction‑mediated toxicity, thus exerting a cytoprotective function. Paradoxically, ferritin can be degraded via ferritinophagy, a selective autophagic process that releases toxic ferrous iron and directly triggers ferroptosis. This review systematically reviews the role of ferritin within the iron homeostasis network to elucidate the connection between the dysregulation of iron metabolism and the pathological mechanisms of neurodegenerative diseases. The study focused on the potential role of ferritin as a biomarker for early diagnosis, therapeutic strategies targeting ferritin pathways to restore iron homeostasis and the clinical translational value of magnetic resonance imaging‑based non‑invasive quantification of cerebral iron deposition. It is crucial to elucidate the multidimensional roles of ferritin in neurodegeneration to provide a theoretical foundation for precision diagnostic and therapeutic approaches.