FOXO4 as a Redox-Sensitive Regulator of Antioxidant Defense and Cellular Senescence: Cysteine-Based Signaling, p53
Diana-Maria Mateescu1, Dragos-Mihai Gavrilescu2, Adelina-Raluca Marinescu3
1Department of General Medicine, Doctoral School, "Victor Babes" University of Medicine and Pharmacy, Eftimie Murgu Square 2, 300041 Timisoara, Romania.
Abstract:
(1) Background: Reactive oxygen species (ROS) act as physiological signaling mediators but contribute to oxidative damage, cellular dysfunction, and age-related disease when redox homeostasis fails. Forkhead box O4 (FOXO4) has emerged as a redox-sensitive regulator linking stress adaptation, antioxidant defense, and cellular senescence. This structured narrative review critically evaluates which redox- and aging-related conclusions are supported directly for FOXO4 and which remain inferred from other FOXO isoforms. (2) Methods: PubMed/MEDLINE, Scopus, and Web of Science were searched from inception to May 2026; Google Scholar was used only for supplementary citation tracking and did not contribute a separate platform-level count. Of 420 records, 300 remained after deduplication, 110 full texts were assessed, and 89 publications were retained. FOXO4-related evidence was classified as directly FOXO4-specific (n = 18), FOXO-family/conserved (n = 24), or extrapolated predominantly from FOXO1/FOXO3/DAF-16 (n = 20); 27 contextual publications on redox biology, senescence, disease, and NRF2 were tracked separately. (3) Results: The strongest FOXO4-specific evidence supports three mechanistic axes: cysteine-dependent redox sensing, stress-regulated nuclear trafficking and coactivator engagement through transportin-1 and p300/CBP, and FOXO4-p53-mediated survival of senescent cells. By contrast, direct FOXO4 regulation of commonly cited antioxidant targets, including SOD2, catalase, sestrins, and GADD45, remains insufficiently demonstrated and is inferred mainly from FOXO3 or broader FOXO-family studies. FOXO4-DRI has shown senolytic activity in preclinical models, including vascular endothelium, but has not been clinically validated. (4) Conclusions: FOXO4 is a redox-responsive transcriptional regulator with well-supported roles in cysteine-based signaling and senescent-cell survival, whereas its target-gene-level antioxidant program remains incompletely resolved. Clinical translation of FOXO4-p53 disruption requires isoform- and tissue-specific validation, pharmacokinetic and delivery studies, long-term toxicology, and explicit assessment of p53-dependent tumor surveillance.
Insights
Forkhead box O4 (FOXO4) is a redox-sensitive regulator involved in stress adaptation and cellular senescence. While its roles in redox sensing and senescent cell survival are supported, its antioxidant gene targets require further investigation.
Area of Science:
- * Redox Biology and Aging Research
- * Cellular Senescence and Stress Response Mechanisms
- * Transcriptional Regulation by Forkhead Box Proteins
Background:
- * Reactive oxygen species (ROS) are critical signaling molecules, but their imbalance contributes to oxidative stress, cellular dysfunction, and age-related diseases.
- * Forkhead box O4 (FOXO4) is recognized as a redox-sensitive regulator connecting stress adaptation, antioxidant defense, and cellular senescence.
- * Understanding FOXO4's precise functions is crucial for deciphering aging processes and developing therapeutic strategies.
Purpose of the Study:
- * To critically evaluate the evidence directly supporting FOXO4's roles in redox biology and aging.
- * To distinguish between FOXO4-specific findings and those inferred from other FOXO isoforms.
- * To assess the current understanding of FOXO4's mechanisms and clinical potential.
Main Methods:
- * A structured narrative review of literature from PubMed/MEDLINE, Scopus, and Web of Science.
- * Systematic classification of evidence as FOXO4-specific, FOXO-family conserved, or extrapolated from other FOXO members.
- * Analysis of 420 records, with 89 publications retained for detailed review and evidence classification.
Main Results:
- * Strong FOXO4-specific evidence supports its roles in cysteine-dependent redox sensing, stress-induced nuclear trafficking, and FOXO4-p53-mediated survival of senescent cells.
- * Direct evidence for FOXO4 regulating key antioxidant targets (e.g., SOD2, catalase) is limited and often inferred from FOXO3 or other FOXO family members.
- * FOXO4-DRI demonstrates senolytic activity in preclinical models, but clinical validation is pending.
Conclusions:
- * FOXO4 is a well-established redox-responsive regulator with confirmed roles in cysteine signaling and senescent cell survival.
- * The specific antioxidant gene regulatory program of FOXO4 remains incompletely elucidated.
- * Clinical applications targeting FOXO4-p53 interactions require rigorous validation, including isoform specificity, pharmacokinetics, and safety assessments.
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