Significance: The lack of disease-modifying treatments for Alzheimer's disease (AD) that substantially alter the course of the disease highlights the need for new biological models of disease progression and neurodegeneration. Oxidation of macromolecules within the brain, including lipids, proteins, and DNA, is believed to contribute to AD pathophysiology, concomitant with dysregulation of redox-active metals, such as iron. Creating a unified model of pathogenesis and progression underpinned by iron dysregulation and redox dysregulation in AD could lead to new therapeutic targets with disease-modifying potential. Recent Advances: Ferroptosis, which was named in 2012, is a necrotic form of regulated cell death that depends on both iron and lipid peroxidation. While it is distinct from other types of regulated cell death, ferroptosis is regarded as being mechanistically synonymous with oxytosis. The ferroptosis paradigm has great explanatory potential in describing how neurons degenerate and die in AD. At the molecular level, ferroptosis is executed by the lethal accumulation of phospholipid hydroperoxides generated by the iron-dependent peroxidation of polyunsaturated fatty acids, while the major defensive protein against ferroptosis is the selenoenzyme, glutathione peroxidase 4 (GPX4). An expanding network of protective proteins and pathways have also been identified to complement GPX4 in the protection of cells against ferroptosis, with a central role emerging for nuclear factor erythroid 2-related factor 2 (NRF2). Critical Issues: In this review, we provide a critical overview of the utility of ferroptosis and NRF2 dysfunction in understanding the iron- and lipid peroxide-associated neurodegeneration of AD. Future Directions: Finally, we discuss how the ferroptosis paradigm in AD is providing a new spectrum of therapeutic targets. Antioxid. Redox Signal. 39, 141-161.
Keywords: NRF2; astrocyte; cell death; ferroptosis; iron; lipid peroxidation; neurodegeneration; neuroinflammation; neuron.