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Kidney Week

Abstract: TH-OR66

Downregulation of O-GlcNAcylation, a Metabolic Regulator, Attenuates PKD Progression

Session Information

Category: Genetic Diseases of the Kidneys

  • 1201 Genetic Diseases of the Kidneys: Cystic

Authors

  • Kavanaugh, Matthew A., University of Kansas School of Medicine, Kansas City, Kansas, United States
  • Isai, Dona Greta, University of Kansas School of Medicine, Kansas City, Kansas, United States
  • Wang, Henry, University of Kansas School of Medicine, Kansas City, Kansas, United States
  • Artigues, Antonio, University of Kansas School of Medicine, Kansas City, Kansas, United States
  • Villar, Maria T., University of Kansas School of Medicine, Kansas City, Kansas, United States
  • Parnell, Stephen C., University of Kansas School of Medicine, Kansas City, Kansas, United States
  • Slawson, Chad, University of Kansas School of Medicine, Kansas City, Kansas, United States
  • Wallace, Darren P., University of Kansas School of Medicine, Kansas City, Kansas, United States
  • Tran, Pamela Vivian, University of Kansas School of Medicine, Kansas City, Kansas, United States
Background

Altered cell metabolism is an important component of autosomal dominant polycystic kidney disease (ADPKD) pathogenesis, but drivers of these alterations are not understood. The addition of O-linked b-N-acetylglucosamine (O-GlcNAc) onto protein substrates by O-GlcNAc transferase (OGT) is a nutrient-sensitive post-translational modification that integrates multiple metabolic signals. We have reported that protein O-GlcNAcylation is increased in kidneys of ADPKD patients and PKD mouse models. Thus, we hypothesize that increased O-GlcNAcylation is pathogenic in ADPKD.

Methods

We generated juvenile and adult Pkd1 conditional knockout (cko) and Pkd1;Ogt double knockout (dko) mice using the HoxB7-Cre and the doxycycline-inducible Pax8rtTA;LC1-Cre recombinases (induced from 4-6 weeks of age). Juvenile and adult mouse kidneys were analyzed on postnatal day (P)14 and at 4 months of age, respectively. To identify hyper-O-GlcNAcylated proteins in PKD, immunoprecipitation and Western blot were performed on mouse renal tissue extracts. Mass spectrometry is underway to map O-GlcNAcylation sites on identified proteins. To examine mechanisms in human ADPKD, cyst-lining epithelial cells were cultured in a 3D collagen matrix and an OGT inhibitor was tested on in vitro cyst formation.

Results

In juvenile mice, Ogt deletion in Pkd1 cko mice reduced renal cystogenesis and kidney weight:body weight ratios (KW/BW); restrained renal cilia lengths; reduced inflammation and fibrosis; increased activation of the energy sensor AMPK; and improved kidney function. Further, while Pkd1 cko mice die between P14-P20, Pkd1;Ogt dko mice continue to thrive beyond 14 weeks of age. Additionally, AMPK was found to be hyper-O-GlcNAcylated at P14 in Pkd1 cko kidneys. Similarly, in adult mice, deletion of Ogt in Pkd1 cko mice reduced renal cystogenesis and KW/BW. Finally, OGT inhibition reduced in vitro cyst formation by cultured human ADPKD cells.

Conclusion

In PKD, protein O-GlcNAcylation, including of AMPK, is increased, and deletion or inhibition of OGT reduces cyst growth and disease severity, demonstrating that O-GlcNAcylation is an important driver of PKD progression. We propose that targeting O-GlcNAcylation may have therapeutic potential in ADPKD.

Funding

  • Other U.S. Government Support