Exercise-Driven NRF2 Activation as a Systemic Neuroprotective Strategy: Integrating Redox Biology, Muscle-Brain...

Neurodegenerative diseases, including Alzheimer's, Parkinson's, and Huntington's diseases, are characterized by progressive neuronal dysfunction and loss. Recent evidence highlights the importance of the nuclear factor erythroid 2-related factor 2 (NRF2) pathway, a key regulator of cellular defense mechanisms, in maintaining neuronal health and function. A narrative literature search was conducted using PubMed, Scopus, Web of Science, and Google Scholar to identify relevant experimental, clinical, and review studies on NRF2 signaling, physical exercise, oxidative stress, muscle-brain crosstalk, and neurodegenerative diseases. Keywords included "NRF2", "Nrf2/Keap1/ARE", "physical exercise", "exercise-induced oxidative stress", "myokines", "exerkines", "Alzheimer's disease", "Parkinson's disease", "Huntington's disease", and "amyotrophic lateral sclerosis". NRF2 modulates the expression of a variety of antioxidant and cytoprotective genes, contributing to the protection of neurons against oxidative stress, inflammation, and protein aggregation, processes central to the pathogenesis of neurodegenerative diseases. Additionally, physical activity has been identified as a powerful modulator of NRF2 activation, with exercise offering neuroprotective effects through the induction of NRF2-mediated pathways. This review explores the interplay between NRF2 activation and physical exercise in the context of neurodegenerative diseases, detailing the molecular mechanisms by which exercise influences NRF2 activity to combat cellular damage and enhance neuroprotection. We discuss the therapeutic potential of combining exercise regimens with NRF2-targeted therapies, highlighting the promise of this dual approach in slowing disease progression, improving cognitive function, and enhancing quality of life in affected individuals. Furthermore, we examine the challenges and future directions for clinical implementation, including optimal exercise protocols and the development of NRF2-based pharmacological interventions. This review underscores the importance of NRF2 as a central mediator of neuroprotection and the therapeutic promise of physical activity in the management of neurodegenerative diseases.