FOXO4-DRI

Abstract

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.

Abstract

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 p53TAD2 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.

Abstract

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.