Kidney Week

Abstract: SA-PO0148

Sirtuin-3 Deletion in the Distal Nephron Protects Against Ischemic AKI

Session Information

• AKI: Mechanisms - 3
  November 08, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 103 AKI: Mechanisms

Authors

• Chen, Yanting, Duke University, Durham, North Carolina, United States

Yanting Chen, PhD

• Wu, Chia-Chun, Duke University, Durham, North Carolina, United States

Chia-Chun Wu, MD

• Kitai, Hiroki, Duke University, Durham, North Carolina, United States

Hiroki Kitai, MD, PhD

• Sheng, Huaxin, Duke University, Durham, North Carolina, United States

Huaxin Sheng, MD

• Hirschey, Matthew, Duke University, Durham, North Carolina, United States

Matthew Hirschey, PhD

• Souma, Tomokazu, Duke University, Durham, North Carolina, United States

Tomokazu Souma, MD, PhD

• Crowley, Steven D., Duke University, Durham, North Carolina, United States

Steven D. Crowley, MD

• Privratsky, Jamie R., Duke University, Durham, North Carolina, United States

Jamie R. Privratsky, MD, PhD

Background

The kidney is highly enriched in mitochondria, and mitochondrial dysfunction is a central contributor to AKI pathogenesis. Sirtuin-3 (SIRT3), a mitochondrial deacetylase, plays a critical role in preserving mitochondrial integrity. SIRT3 has been shown to protect against toxic AKI. However, the segment-specific functions of SIRT3 in the nephron following AKI remain poorly understood. We hypothesized that deletion of SIRT3 in both proximal and distal tubules would exacerbate ischemic AKI.

Methods

Transgenic mice: whole nephron SIRT3 deletion (Pax8-rtTA/Tet-O-Cre/SIRT3^fl/fl – SIRT3 iKKO), proximal tubule deletion (PepCK-Cre/SIRT3^fl/fl – SIRT3 PTKO), and distal tubule deletion (Ksp-Cre/SIRT3^fl/fl – SIRT3 DTKO) and with mitochondrial reporter (Ksp-Cre/SIRT3^fl/fl/MITO-Tag - SIRT3 DTKO^MITO). Model: unilateral ischemia/reperfusion (I/R) with contralateral nephrectomy harvested at 24 hours. Primary outcome: serum creatinine. Secondary outcomes: serum BUN, kidney histologic injury scoring, and kidney injury markers. Exploratory analysis: mRNA and protein levels of SIRT3 in whole kidneys of transgenic mice, single-cell RNA sequencing (scRNA-seq) of kidneys from wildtype mice following I/R. Statistics: 2 groups – unpaired T test; 2 groups with independent variables - two-way ANOVA with Bonferroni post-hoc.

Results

Neither SIRT3 iKKO nor SIRT3 PTKO displayed worsened acute ischemic AKI compared to littermate counterparts. However, we noted a significant decrease in SIRT3 expression in the kidneys of mice following ischemic AKI. scRNA-seq revealed that SIRT3 expression is highest at baseline in proximal tubule segments but decreases following I/R. In contrast, in medullary distal tubular segments chronically exposed to hypoxic environment, SIRT3 expression is lower at baseline and increases after I/R injury. Interestingly, compared to littermates, SIRT3 DTKO mice displayed improved ischemic AKI. TUNEL staining revealed fewer TUNEL-positive cells in SIRT3 DTKO kidneys. Sorted distal tubule cells from SIRT3 DTKO^MITO mice showed reduced expression of ferroptosis-related genes compared to littermates.

Conclusion

Unexpectedly, SIRT3 deletion in kidney distal tubule cells reduces ferroptosis-mediated cell death and attenuates ischemic AKI, findings that could have implications for ischemic preconditioning.

Funding

• NIDDK Support

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025ptxhnew1