FOXO4

Research Benefits

• Senolytic Research — FOXO4-DRI is a D-retro-inverso peptide designed to selectively induce apoptosis in senescent cells, making it a leading research tool in the senolytic field.
• Cellular Aging Studies — By targeting the FOXO4-p53 interaction exclusive to senescent cells, FOXO4-DRI enables precise investigation of cellular senescence contributions to tissue dysfunction.
• Proteolytic Resistance — The D-retro-inverso design confers resistance to proteolytic degradation, providing extended bioavailability compared to native L-peptide sequences.
• Selective Targeting — Unlike broad cytotoxic agents, FOXO4-DRI demonstrates selectivity for senescent over non-senescent cells in published studies, reducing off-target effects in research models.
• Aging Biology Platform — FOXO4-DRI serves as a reference compound for studying the consequences of senescent cell clearance on tissue repair, fibrosis, and organ function in aging models.

Mechanism of Action

FOXO4-DRI is a modified peptide that disrupts the protein-protein interaction between FOXO4 and p53 in senescent cells. Its mechanism is highly specific to the senescent cell phenotype.

FOXO4-p53 Disruption: In senescent cells, the transcription factor FOXO4 sequesters the tumor suppressor p53 in PML nuclear bodies, preventing p53 from activating its pro-apoptotic transcriptional program. FOXO4-DRI competitively displaces p53 from this complex.

p53-Mediated Apoptosis: Once freed from FOXO4, p53 translocates to the mitochondria and activates the intrinsic apoptotic cascade. This includes cytochrome c release, caspase-9 and caspase-3 activation, leading to controlled cell death of the senescent cell.

Selectivity: Non-senescent cells do not rely on the FOXO4-p53 sequestration mechanism for survival, so FOXO4-DRI does not induce apoptosis in healthy, proliferating cells. This selectivity has been demonstrated in vitro with senescence-induced fibroblast and hepatocyte models.

D-Retro-Inverso Design: The peptide uses D-amino acids in a reversed sequence, maintaining the side-chain topology of the native L-peptide while conferring resistance to enzymatic proteolysis, extending its functional half-life in biological systems.

Research Protocol

The following information is derived from published research literature and is intended for reference in research settings only.

Reconstitution

Reconstitute lyophilized FOXO4-DRI in sterile DMSO to create a stock solution (typically 10 mM), then dilute into PBS or culture media for working concentrations.

Research Dosing (from published studies)

• In vitro: 10-50 μM in cell culture media for senescent cell clearance assays (IMR90 fibroblasts, hepatocyte models).
• In vivo (murine): 5 mg/kg intraperitoneal injection, administered 3 times per week for 3-4 weeks in published aging studies.
• Controls: Scrambled D-retro-inverso peptide of equivalent length serves as the standard negative control.

Assessment Endpoints

SA-β-galactosidase staining, p16^INK4a expression, SASP factor panels (IL-6, IL-8, MCP-1), and cleaved caspase-3 immunohistochemistry are common readouts.

Storage

Store lyophilized at -20°C to -80°C. DMSO stocks at -80°C. Avoid aqueous storage for extended periods.

Safety & Handling

Research Use Only. This product is not intended for human or veterinary diagnostic or therapeutic use.

Storage Conditions

• Lyophilized: -20°C to -80°C, desiccated
• Stock solutions (DMSO): -80°C, aliquoted to avoid freeze-thaw
• Protect from light at all times

Known Considerations from Literature

• FOXO4-DRI is a research-grade senolytic. No toxicology profile equivalent to pharmaceutical-grade compounds exists.
• In murine studies, transient weight loss and neutropenia have been observed at high doses.
• The D-amino acid composition may limit renal clearance; investigators should monitor renal function markers in chronic dosing studies.
• Combination with other senolytics (dasatinib, quercetin, navitoclax) should be carefully titrated to avoid excessive apoptotic burden.

Handling

Use standard laboratory PPE. DMSO stock solutions can penetrate skin; wear nitrile gloves. Work in a fume hood when handling DMSO solutions.

Frequently Asked Questions

What does "D-retro-inverso" mean?

D-retro-inverso (DRI) is a peptide design strategy that uses D-amino acids (mirror-image of natural L-amino acids) in a reversed sequence. This maintains the original side-chain spatial orientation while making the peptide resistant to protease degradation, extending its biological activity.

How does FOXO4-DRI selectively target senescent cells?

Senescent cells uniquely depend on FOXO4 to sequester p53 and prevent apoptosis. FOXO4-DRI disrupts this specific interaction, freeing p53 to activate cell death. Non-senescent cells do not use this survival mechanism, so they are unaffected.

What is cellular senescence?

Cellular senescence is a state of permanent growth arrest triggered by DNA damage, telomere shortening, or oncogene activation. Senescent cells accumulate with age and secrete inflammatory factors (the SASP), contributing to tissue dysfunction and age-related pathology.

What purity is this product?

BeaCapra FOXO4-DRI is manufactured to ≥99% purity as confirmed by HPLC and mass spectrometry, with a COA provided for each batch.

Why is DMSO used for reconstitution?

FOXO4-DRI has limited aqueous solubility due to its D-amino acid composition. DMSO provides complete dissolution for stock preparation. Final working solutions are diluted into aqueous buffers, keeping DMSO concentration below 0.1% in cell culture applications.