Abstract: TH-PO107
Proximal Tubular-Specific Cell Cycle Arrest Ameliorates AKI in Mice
Session Information
- AKI: Mechanisms - I
November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
Authors
- Wulfmeyer, Vera Christine, Medizinische Hochschule Hannover, Hannover, Niedersachsen, Germany
- Soerensen-Zender, Inga, Medizinische Hochschule Hannover, Hannover, Niedersachsen, Germany
- Voß, Vanessa, Medizinische Hochschule Hannover, Hannover, Niedersachsen, Germany
- Rong, Song, Medizinische Hochschule Hannover, Hannover, Niedersachsen, Germany
- Marlier, Arnaud, Altos Labs Inc, Redwood City, California, United States
- Schmidt-Ott, Kai M., Medizinische Hochschule Hannover, Hannover, Niedersachsen, Germany
- Melk, Anette, Medizinische Hochschule Hannover, Hannover, Niedersachsen, Germany
- Schmitt, Roland, Medizinische Hochschule Hannover, Hannover, Niedersachsen, Germany
Group or Team Name
- Roland Schmitt Lab.
Background
Acute kidney injury (AKI) is a major medical and economic burden. Renal tubular epithelial cells are normally arrested in the G0 phase of the cell cycle (CC), but are rapidly entering the CC after AKI. Recent studies indicate that regulated CC is required for optimal regeneration following AKI. Cyclin D1 (Ccnd1) is essential for CC progression from G1- to S-phase. We characterized a proximal tubular (PT)-specific Ccnd1 knock-out (KO) and a siRNA-based Ccnd1 knock-down (KD) in a murine ischemia-reperfusion (IRI) model.
Methods
Tamoxifen (tam)-inducible proximal tubular Ccnd1 KO mice (Ccnd1flox/flox::Slc34a1CreERT2) underwent IRI surgery following vehicle (veh) or tam treatment. Serum creatinine/urea, histology, leukocyte infiltration, cell cycle phases, and fibrosis were assessed (2h, 1d, 3d, 7d, 14d, 28d after IRI; n=8 per group). A Ccnd1-siRNA KD was established in vitro (primary tubular epithelial cells) and in vivo (1nmol siRNA/g mouse; 24h before and at reperfusion) and evaluated by the abovementioned parameters on day 14 after IRI. To evaluate the underlying mechanism, RNAseq analysis of isolated PT (n=3) and MALDI-TOF-MSI of kidneys 1d after IRI (n=5) were performed.
Results
PT-specific Ccnd1 KO attenuated the functional decline of AKI (S-crea 312±74% vs. 142±11% (3d relative to 0d); p=0.036). KD mice showed a comparable outcome. At day 1 and 3 after IRI, KO kidneys had reduced histological damage (AKI score maximal 4; 1d: 2.26±0.13 vs. 1.84±0.11; p=0.028; 3d: 2.68±0.12 vs. 2.06±0.16; p=0.009). KO kidneys showed a 15-fold reduction in leukocyte infiltration (3d: 12.8±0.75% leukocytes/all cells vs. 0.81±0.14%; p<0.0001). At later time points after IRI (28d), KO mice showed no damage/regeneration benefit (histology and brush border staining). RNAseq analysis revealed a decreased expression of CC-associated genes in KO proximal tubules. Moreover, depletion of adenosine monophosphate was strongest in the cortex of WT kidneys.
Conclusion
Specific ablation of Ccnd1 in the proximal tubule or systemic antagonism of Ccnd1 reduced proliferation in the kidney after IRI. This was associated with reduced AKI injury at early time points after IRI in KO and KD models. Our data suggest a cell cycle-associated, energy-dependent mechanism of protection.