Kidney Week

Abstract: SA-PO0253

Proximal Tubular FoxO3 Deletion Protects Against AKI

Session Information

• AKI: Mechanisms - Cell Signaling
  October 24, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 103 AKI: Mechanisms

Authors

• Sharma, Shivani, Washington University in St Louis, St. Louis, Missouri, United States

Shivani Sharma, MS, MSc, PhD

• Kivan, Husam, Washington University in St Louis, St. Louis, Missouri, United States

Husam Kivan, MD

• Newberry, Katherine P., Washington University in St Louis, St. Louis, Missouri, United States

Katherine P. Newberry

• Gewin, Leslie S., Washington University in St Louis, St. Louis, Missouri, United States

Leslie S. Gewin, MD, FASN

Group or Team Name

• Gewin's Lab

Background

Acute kidney injury (AKI) primarily affects proximal tubules (PT) and is associated with high mortality and limited therapies. The transcription factor forkhead box-O3 (FoxO3) regulates redox homeostasis, autophagy, and apoptosis, and previous work showed that deleting FoxO3 throughout the tubules worsened chronic kidney disease. However, its role in PT during AKI is unclear. We hypothesized that PT-specific FoxO3 deletion would exacerbate AKI.

Methods

We deleted FoxO3 throughout the renal tubules using Pax8-rtTA;tetO-Cre (Foxo3^Pax8-Cre) mice and doxycycline-containing diet for 3 weeks and generated PT-specific deletion using GGT-Cre (Foxo3^GGT-Cre). After recombination, AKI was induced by intraperitoneal injections of aristolochic acid (AA), with male Foxo3^Pax8-Cre and Foxo3^GGT-Cre mice receiving 5 mg/kg for 3 days and female Foxo3^GGT-Cre mice receiving 12 mg/kg for 4 days; all mice were sacrificed 1 week after last injection. Renal function and injury were assessed by BUN, creatinine, and Lcn2 expression, while apoptosis and inflammation were evaluated by cleaved caspase-3, TUNEL and F4/80 staining. Primary PT cells were isolated from Foxo3^fl/fl mice and treated with adeno-Cre to generate Foxo3^-/- PT cells and injured with AA or hypoxia (1%O₂)/reperfusion (H/R). Markers of ferroptosis (GPX4, ACSL4), an iron-dependent lipid peroxidation, lipid peroxidation (BODIPY-C11), cell death (annexin/PI) were assessed by Western blot, qPCR, and flow cytometry. PT cells were treated with ferroptosis inhibitor ferrostatin-1 (50µM).

Results

Foxo3^Pax8-Cre mice had worsened renal function (p=0.003) after AA-induced AKI. In contrast, Foxo3^GGT-Cre males and females had preserved renal function (p=0.001), reduced tubular injury(p=0.001), cell death, and macrophage infiltration compared with floxed controls. FoxO3^-/- PT cells showed less cell death after AA and H/R injury than Foxo3^fl/fl PT cells. Both AA-treated Foxo3^GGT-Cre and FoxO3^-/- had reduced ACSL4 and augmented GPX4, consistent with decreased ferroptosis. This was confirmed by lower BODIPY-C11 expression in FoxO3^-/- PT cells. Additionally, treatment with ferrostatin-1 eliminated the increased cell death in AA-injured FoxO3^-/- and FoxO3^+/+ PT cells.

Conclusion

Deleting FoxO3 throughout kidney tubules worsened AKI, but PT-specific deletion protected against AKI through reducing ferroptosis, suggesting segment-specific roles of FoxO3 in regulating tubular injury responses in AKI.

Acknowledgment

This research was funded by grant #R01-DK-108968 and VA Merit Award 1I01BX003425-01A

Funding

• NIDDK Support