Beyond Antioxidants: The Emerging Role of Nrf2 Activation in Amyotrophic Lateral Sclerosis (ALS).

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder involving the progressive degeneration of upper and lower motor neurons. While oxidative stress, RNA-binding protein (RBP) pathology, mitochondrial dysfunction, and glial-neuronal dysregulation is involved in ALS pathogenesis, current therapies provide limited benefit, underscoring the need for multi-target disease-modifying strategies. Nuclear factor erythroid 2-related factor 2 (Nrf2), classically regarded as a master regulator of redox homeostasis, has recently emerged as a central integrator of cellular stress responses relevant to ALS. Beyond its canonical antioxidant function, Nrf2 regulates critical pathways involved in mitochondrial quality control, proteostasis, nucleocytoplasmic transport, RNA surveillance, and glial reactivity. Experimental models demonstrate that astrocyte-specific Nrf2 activation enhances glutathione metabolism, suppresses neuroinflammation, promotes stress granule disassembly, and reduces RBP aggregation. In C9orf72-linked ALS, Nrf2 activation mitigates dipeptide repeat protein toxicity and restores RNA processing fidelity via modulation of nonsense-mediated decay and R-loop resolution. Recent advances in Nrf2-targeted interventions including Keap1-Nrf2 protein-protein interaction inhibitors, dual Nrf2/HSF1 activators, and cell-type-selective Adeno-associated virus 9 (AAV9) vectors show promise in preclinical ALS models. These multimodal approaches highlight Nrf2's therapeutic versatility and potential to address the upstream convergence points of ALS pathogenesis. Taken together, positioning Nrf2 as a systems-level regulator offers a novel framework for developing precision-based therapies in ALS. Integrating Nrf2 activation with RNA- and glia-directed strategies may enable comprehensive modulation of disease progression at its molecular roots.