Kidney Week

Abstract: TH-PO217

Podocyte-Mediated Proximal Tubule Preconditioning Is Protective in Diabetic Kidney Disease

Session Information

• Diabetic Kidney Disease: Basic - I
  November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: Diabetic Kidney Disease

• 601 Diabetic Kidney Disease: Basic

Authors

• Owusu Frimpong, Bismark, Stony Brook University, Stony Brook, New York, United States

Bismark Owusu Frimpong,

• Gujarati, Nehaben A., Stony Brook University, Stony Brook, New York, United States

Nehaben A. Gujarati,

• Mallipattu, Sandeep K., Stony Brook University, Stony Brook, New York, United States

Sandeep K. Mallipattu,

Background

Diabetic kidney disease (DKD) is a glomerulopathy, with inciting events occurring in cells that comprise the glomerulus. However, recent findings have implicated proximal tubule (PT) injury in the progression of DKD. Potential mechanisms by which PT can be preconditioned to prevent the progression of DKD remain poorly understood. The aim of this study is to demonstrate that podocyte-specific induction of a zinc finger transcription factor, Krüppel-like factor 6 (KLF6), attenuates DKD by preconditioning the PT against DKD progression.

Methods

Podocyte-specific induction of KLF6 (hKLF6^PODTA) were generated using NPHS2-rtTA and TRE-KLF6 mice, under doxycycline treatment. Diabetes was induced with UNx-STZ, with SHAM-Veh serving as the control. Single nucleus (sn)RNA-seq was conducted from kidney cortex of all mice. Conditioned media (CM) from podocytes isolated from hKLF6^PODTA and control mice were collected. CAMK1d was knocked down in HK2 cells (sh-CAMK1d). CAMK1D signaling was pharmacologically inhibited using STO-609, an inhibitor of the upstream kinase CAMKK, in primary (1°) PT cells. Oxygen consumption rate (OCR) was measured with Seahorse Analyzer.

Results

Diabetic hKLF6^PODTA mice exhibited less albuminuria, podocyte injury, glomerulosclerosis, and tubulointerstitial injury compared to diabetic controls. Clustering of the snRNA-seq data identified a subpopulation of PTs predominant in the hKLF6^PODTA groups. Gene Set Enrichment Analysis of this subpopulation showed an enrichment for mitochondrial respiration pathways and upregulation in Camk1d gene expression and signaling. In assessing the role of CAMK1d in PTs, we found that sh-CAMK1d cells exhibited slower growth and lower cell viability with a larger proportion in s-phase of cell cycle compared to control cells. 1° PT cells treated with STO-609 validated this decrease in cell viability and OCR. Additionally, 1° PT cells primed with CM from hKLF6^PODTA podocytes had preserved OCR compared to PT treated with CM from control podocytes in high glucose conditions.

Conclusion

These data suggest that podocyte-specific induction of KLF6 preconditions the proximal tubules against DKD progression by upregulating CAMK1d signaling.

Funding

• NIDDK Support