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Abstract: SA-OR17

Single-Cell Transcriptomics Reveal Pyroptosis and Ferroptosis Inhibition Ameliorate Maladaptive AKI-to-CKD Progression and Epithelial-to-Immune Phenotype Switch

Session Information

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Balzer, Michael S., Institute for Diabetes, Obesity and Metabolism, UPenn, Philadelphia, Pennsylvania, United States
  • Doke, Tomohito, Institute for Diabetes, Obesity and Metabolism, UPenn, Philadelphia, Pennsylvania, United States
  • Ma, Ziyuan, Institute for Diabetes, Obesity and Metabolism, UPenn, Philadelphia, Pennsylvania, United States
  • Palmer, Matthew, Department of Pathology and Laboratory Medicine, UPenn, Philadelphia, Pennsylvania, United States
  • Susztak, Katalin, Institute for Diabetes, Obesity and Metabolism, UPenn, Philadelphia, Pennsylvania, United States

Group or Team Name

  • Susztak Lab
Background

Following acute kidney injury (AKI) renal repair is possible to a certain extent. However, maladaptation to AKI leads to progression towards chronic kidney disease (CKD). Unwiring the incompletely understood processes driving both progression and repair might identify therapeutic targets to halt or reverse AKI-to-CKD progression.

Methods

Here we profiled transcriptomic changes at single-cell level over time in acutely injured kidneys of mice subjected to mild and severe bilateral ischemic reperfusion injury (IRI), modeling repair and maladaptation, respectively. Kidney function, structure, bulk and single-cell gene expression analyses were performed 1, 3 and 14d after ischemia. We used motif enrichment, trajectory, drug response pattern and cell-cell interaction analyses to define key drivers of failed and successful regeneration, finally informing in vivo experiments with 2 small molecules effectively ameliorating maladaptation.

Results

Long bilateral ischemia resulted in sustained renal failure (1-14d) and severe fibrosis at 14d, suggesting maladaptation, while after short ischemia early (1-3d) functional and structural impairment returned to baseline at 14d, suggesting repair. Analyzing 136,794 high-quality kidney cell transcriptomes, we uncover a maladaptive proximal tubule (PT) signature 14d after long IRI, characterized by sustained upregulation of pyroptosis and ferroptosis genes. We define the PT gene regulatory logic behind both regeneration and maladaptation, highlighting myeloid transcription factors (TFs) as novel potential drivers of AKI-to-CKD progression upstream of inflammasome effectors. Additionally, in cell-cell interaction analyses we show how PT cells acquire an immune phenotype during maladaptation. Finally, prompted by analyses of drug response transcriptional changes we show that inhibition of pyroptosis (VX765) and ferroptosis (liproxstatin) in vivo normalized single-cell transcriptomic kidney signatures despite severe IRI.

Conclusion

Using single-cell transcriptomics we reveal pyroptosis and ferroptosis as key druggable pathways of a detrimental PT signature associated with maladaptation to AKI and progression towards CKD, which was driven by TFs typically active in myeloid cells and characterized by a an epithelial-to-immune phenotype switch.

Funding

  • NIDDK Support