FOXO4-DRI

Overview

FOXO4-DRI is a D-retro-inverso peptide designed to disrupt the FOXO4-p53 interaction in senescent cells. It is studied as a senolytic agent that selectively induces apoptosis in senescent cells while sparing normal cells.

Mechanism of Action

In senescent cells, FOXO4 sequesters p53 in PML nuclear bodies, preventing apoptosis. FOXO4-DRI competitively disrupts this interaction, releasing p53 to trigger the intrinsic apoptosis cascade. The D-retro-inverso modification (D-amino acids in reverse sequence) resists protease degradation while maintaining binding affinity. Selectivity arises because the FOXO4-p53 interaction is specifically upregulated in senescent cells.

Research Summary

Baar et al. (Cell, 2017, PMID 28340339) identified FOXO4 as a pivot for senescent-cell viability and designed a cell-penetrating D-retro-inverso peptide that disrupts the FOXO4-p53 interaction, selectively triggering apoptosis in senescent cells while sparing proliferating cells. In vivo, the peptide neutralized doxorubicin chemotoxicity and, in fast-aging XpdTTD/TTD and naturally aged mice, restored fur density, renal function, and fitness. This is the only primary in vivo study; evidence is preclinical only. No human clinical trials have been registered or completed. Safety in humans is unknown — as a systemic senolytic inducing apoptosis, theoretical risks include impaired wound healing, immune perturbation, and off-target effects on quiescent stem-cell populations.

Dosing Information

Reported Side Effects

• Limited human safety data
• Transient diarrhea observed in preclinical mouse models
• Injection site reactions (preclinical)
• Potential off-target apoptosis at supratherapeutic doses (preclinical)

Research References

• Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis in Response to Chemotoxicity and Aging (2017)