Overview
FOXO4-DRI is a synthetic retro-inverso peptide, meaning it is an engineered version of a naturally derived sequence that has been modified to improve its stability and cellular penetration. It belongs to a class of compounds known as senolytic peptides, which are studied in research settings for their ability to selectively target and influence senescent cells — cells that have stopped dividing and are thought to accumulate with age. In laboratory research, FOXO4-DRI has been investigated specifically for its interaction with the FOXO4-p53 protein axis, a molecular pathway that appears to play a role in how senescent cells survive. Scientists have used this peptide in preclinical studies to better understand the biology of cellular aging, vascular function, and neurological processes. FOXO4-DRI is intended strictly for research purposes and is not approved for human use or consumption.
Research & Bioactivity
Researchers have studied FOXO4-DRI primarily in the context of cellular senescence, investigating its capacity to selectively disrupt the interaction between the FOXO4 protein and p53, a molecular axis implicated in the survival of senescent cells. In vitro studies and aged mammalian models have examined how this disruption may trigger apoptosis in senescent cells while leaving healthy, non-senescent cells largely unaffected. Research has investigated the peptide's relevance across multiple tissue types, including vascular endothelial cells, where studies have explored its relationship to markers of vascular aging, and in reproductive biology, where aged mouse models have been used to examine its effects on Leydig cell senescence and associated changes in spermatogenesis. Additional research has examined FOXO4-DRI in the context of pathological fibroblast populations found in keloid tissue, using single-cell RNA sequencing and other molecular tools to characterize senescence-associated secretory phenotype activity. Studies have also investigated the peptide's potential relevance to brain aging, with research in aged mammalian models exploring the FOXO4-p53 axis as a mechanistic target in neurological contexts. Structural research using NMR modeling has further examined how FOXO4-DRI interacts with the disordered transactivation domain of p53 at the molecular level, providing mechanistic insight into its observed selectivity in preclinical research settings.
Published Research
Targeting the FOXO4-p53 axis by retro-inverso peptide senolytic agents: a pharmacological strategy to mitigate brain aging and cognitive decline.
Alameen AAM, Al-Kuraishy HM, Fawzy MN, Batiha GE — 2026
Cellular senescence, driven by the interaction between FOXO4 and p53, is increasingly recognized as a crucial mechanism in brain aging and the development of neurodegenerative disorders. The senolytic peptide FOXO4-DRI, which has been thoughtfully designed, selectively disrupts the FOXO4-p53 complex, inducing apoptosis in senescent cells while preserving healthy tissue. In aged mammalian models, administering FOXO4-DRI decreases the accumulation of senescent cells, restores cerebral blood flow and the integrity of the blood-brain barrier (BBB), reverses hippocampal atrophy, and enhances cognitive function. Furthermore, in models of Alzheimer's disease (AD) and tauopathy, this intervention eliminates amyloid-β and pathological tau, leading to improved memory performance. Preliminary human studies involving FOXO4-axis modulators, such as high-dose fisetin, show a reduction in the senescence-associated secretory phenotype (SASP) and enhancements in cognitive and physical measures among older adults. These findings collectively identify the FOXO4-p53 axis as a potential pharmacological target in brain aging and highlight senolytic therapy as a promising strategy for altering diseases to postpone or reverse age-related cognitive decline. This review consolidates recent findings indicating that FOXO4-dependent senescence significantly contributes to neuroinflammation, synaptic dysfunction, and impaired neurogenesis in the aging brain.
FOXO4-DRI regulates endothelial cell senescence via the P53 signaling pathway.
Hu Z, Li F, Hu C, Shan Q, Tang Z, et al. — 2025
OBJECTIVES: Endothelial cell dysfunction during aging is a key driver of vascular aging and related diseases; however, effective strategies to selectively eliminate senescent endothelial cells and restore vascular function remain lacking. FOXO4-DRI, a novel peptide-based intervention, specifically disrupts the interaction between FOXO4 and P53, thereby inducing apoptosis in senescent cells. This study innovatively focuses on the mechanism by which FOXO4-DRI induces apoptosis in senescent endothelial cells, demonstrating that it functions by activating the p53/BCL-2/Caspase-3 signaling pathway to promote selective apoptosis of these cells. FOXO4-DRI significantly improves vascular function and delays vascular aging. These findings not only enrich the molecular understanding of senescent cell clearance but also provide a novel strategy for precise targeting of endothelial cell senescence in therapeutic applications. MATERIALS AND METHODS: This study aims to analyze the vascular function and aging status of the aorta in naturally aged mice and progeroid model mice following FOXO4-DRI injection. Additionally, it investigates changes in endothelial cell function in senescent endothelial cells induced by oxygen-glucose deprivation (OGD), as well as the protein expression and interaction in the FOXO4-P53 signaling pathway. To assess the impact of FOXO4-DRI on endothelial cell senescence, the senescent endothelial cells were treated with FOXO4-DRI, followed by immunofluorescence and Western blotting experiments. RESULTS: Injection of FOXO4-DRI in both naturally aged and induced aging mice effectively suppressed aortic aging and improved aortic function. Additionally, we found that FOXO4-DRI alleviates endothelial cell senescence induced by OGD, thereby enhancing endothelial cell function. Through co-immunoprecipitation (CO-IP) experiments, we discovered that FOXO4-DRI prevents the binding of FOXO4 to P53, facilitating the phosphorylated P53 nuclear exclusion, which subsequently trigger BAX and cleaved caspase-3, leading to the apoptosis of senescent cells. Ultimately, this mechanism achieves the goal of inhibiting vascular aging. CONCLUSION: FOXO4-DRI promotes the nuclear export of phosphorylated P53 by inhibiting the binding of FOXO4 to P53 in endothelial cells, thereby facilitating the apoptosis of senescent endothelial cells and alleviating aging.
The disordered p53 transactivation domain is the target of FOXO4 and the senolytic compound FOXO4-DRI.
Bourgeois B, Spreitzer E, Platero-Rochart D, Paar M, Zhou Q, et al. — 2025
A central process contributing to the phenotype of aging is cellular senescence. We recently identified the FOXO4 - p53 axis as pivotal in maintaining the viability of senescent cells, and that senescent cells can be targeted selectively with the senolytic peptide FOXO4-DRI. Here, we solve the solution NMR structural models of the p53 transactivation domain in complex with the FOXO4 forkhead domain and in complex with FOXO4-DRI. Strikingly, we find that the disordered FOXO4-DRI binds to the disordered p53 and forms a transiently folded complex. In this complex, both, the FOXO4-derived region and the cationic cell permeability peptide contribute to the interaction. Furthermore, we show that p53 phosphorylation enhances the affinity for both FOXO4 and FOXO4-DRI. Summarizing we provide a detailed characterization of the interaction of p53 with FOXO4 and FOXO4-DRI which is the basis for development of p53 inhibitors to treat diseases linked to cellular senescence such as cancers.
FOXO4-DRI induces keloid senescent fibroblast apoptosis by promoting nuclear exclusion of upregulated p53-serine 15 phosphorylation.
Kong YX, Li ZS, Liu YB, Pan B, Fu X, et al. — 2025
Keloids are pathological scars exhibiting tumour-like aggressiveness and high recurrence rate. Here we find increased proportion of pro-inflammatory and mesenchymal fibroblast subpopulations and senescent fibroblasts, and enhanced expression of senescence-associated secretory phenotype genes using single-cell RNA sequencing analysis, as well as elevated p16 protein and more β-galactosidase-positive cells in keloids. The up-regulated p53-serine15 phosphorylation (p53-pS15) in keloids is identified by phosphospecific protein microarray and western blotting. We further demonstrate that a senolytic FOXO4-D-retro-inverso-isoform peptide (FOXO4-DRI) promotes apoptosis and decreases G0/G1 phase cells in pro-senescence models of keloid organ cultures and fibroblasts, accompanied with p53-pS15 nuclear exclusion. Our study indicates that upregulation of p53-pS15 and p16 maintains a persistent senescent microenvironment to promote cell cycle arrest and apoptosis resistance in keloid fibroblasts. FOXO4-DRI shows potential as a treatment targeting the senescence and apoptosis resistance, and holds promise as an approach to prevent the aggressiveness and relapse of keloids.
FOXO4-DRI improves spermatogenesis in aged mice through reducing senescence-associated secretory phenotype secretion from Leydig cells.
Li Y, Zhang C, Cheng H, Lv L, Zhu X, et al. — 2024
Male ageing is always accompanied by decreased fertility. The forkhead O (FOXO) transcription factor FOXO4 is reported to be highly expressed in senescent cells. Upon activation, it binds p53 in the nucleus, preventing senescent cell apoptosis and maintaining senescent cells in situ. Leydig cells play key roles in assisting spermatogenesis. Leydig cell senescence leads to deterioration of the microenvironment of the testes and impairs spermatogenesis. In this study, we observed that FOXO4-DRI, a specific FOXO4- p53 binding blocker, induced apoptosis in senescent Leydig cells, reduced the secretion of certain Senescence-Associated Secretory Phenotype and improved the proliferation of cocultured GC-1 SPG cells. In naturally aged mice, FOXO4-DRI-treated aged mice exhibited increased sperm quality and improved spermatogenesis.