FOXO4-DRI

Overview

FOXO4-DRI is a synthetic peptide designed to selectively clear senescent cells: a senolytic. Senescent cells no longer divide but do not die either; they accumulate with age and can burden tissue via inflammatory signalling.

The molecule is a D-retro-inverso (DRI) peptide: built from D-amino acids in reversed order, making it far more stable against degradation while preserving the shape of the important side chains. The N-terminal half mimics the FOXO4 segment around the p53 interaction site; the C-terminal basic tail is an HIV-TAT-derived cell-penetrating sequence (Baar 2017).

At Peptalis, FOXO4-DRI is available strictly for research use only: in-vitro laboratory research, not for human or animal use. It is an early-preclinical research molecule, not a medicine.

Mechanism of action

In senescent cells FOXO4 holds the tumour suppressor p53 in the nucleus. FOXO4-DRI disrupts that binding, releasing p53 to set cell death in motion.

Disrupting the FOXO4–p53 interaction

• In senescent cells the transcription factor FOXO4 binds p53 and holds it in the nucleus, so the cell does not execute its death programme and remains stuck in the senescent state.
• FOXO4-DRI mimics the interaction site and competes with native FOXO4, freeing p53.

Selective senolysis (in theory)

• In a senescent cell, where p53 is already 'primed', its release can set programmed cell death in motion, whereas non-senescent cells do not cross that threshold (Baar 2017).
• How selective and how strong this is in complex tissues remains under study.

Research findings

• Foundational (Baar 2017, Cell): designed and tested in cell culture and several mouse models (chemotoxicity, fast-ageing, naturally aged)
• Mouse: FOXO4-DRI reduced senescence of Leydig cells and affected age-related testosterone (Zhang 2020)
• Human cells in vitro: selective removal of senescent chondrocytes (Huang 2021)
• Mouse: targeting matrix production by fibroblasts, reduced bleomycin-induced pulmonary fibrosis (Liu 2023)

Preclinical evidence

• Baar 2017 (Cell): FOXO4-DRI was designed and tested in cell culture and in several mouse models; administration reduced the burden of senescent cells and restored aspects of tissue function.
• Zhang 2020: in aged mice it reduced senescence of Leydig cells and affected testosterone secretion.
• Huang 2021: in expanded human chondrocytes the peptide selectively removed senescent cells.
• Liu 2023: in a mouse model of pulmonary fibrosis it targeted matrix production by fibroblasts and reduced fibrosis.

Human studies

• There are no published human studies of FOXO4-DRI and, as of the reference date, no registered first-in-human trial. All data come from in-vitro work and animal models.

Research context

This profile describes what has been done and found in research. Regulatory and clinical facts are facts about the respective trials and authorities, not claims about a Peptalis product; the compound is for in-vitro laboratory research only (RUO).

Open questions

• All data are preclinical (in-vitro and mouse); there is no published human study. This is precisely where the research still has to begin.
• Selectivity is an open question: does the peptide target only senescent cells? Releasing p53 is powerful but not risk-free.
• Delivery and biodistribution in vivo, and the translatability of mouse models to humans, remain unresolved.

Research outlook

A strong mechanistic idea, a patent-free and relatively under-studied molecule, and a clear gap between preclinical and clinical make FOXO4-DRI an attractive target for senescence research.

Concrete path forward: independent replication of the selectivity, better delivery systems, and the first careful steps toward human research.

Scientific interest

The clearest senolytic peptide anchor: broadens the aging domain.

Clear mechanism: targeted disruption of the FOXO4–p53 interaction.

Patent-free and under-studied: a strong follow-up-research narrative.

Specifications

References

1. Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis in Response to Chemotoxicity and Aging · Baar MP, et al. · Cell · 2017
2. Introduction to FOXO Biology · Link W · Methods Mol Biol · 2019
3. FOXO4-DRI alleviates age-related testosterone secretion insufficiency by targeting senescent Leydig cells in aged mice · Zhang C, et al. · Aging (Albany NY) · 2020
4. Senolytic Peptide FOXO4-DRI Selectively Removes Senescent Cells From Expanded Human Chondrocytes · Huang Y, et al. · Front Bioeng Biotechnol · 2021
5. FOXO4-D-Retro-Inverso targets extracellular matrix production in fibroblasts and ameliorates bleomycin-induced pulmonary fibrosis in mice · Liu Y, et al. · Naunyn Schmiedebergs Arch Pharmacol · 2023

Availability

Not in catalogue · Profile complete · verification and sourcing not yet finished