Abstract: FR-PO620
Hyper-O-GlcNAcylation of AMP-Activated Protein Kinase (AMPK) and Acetylated α-Tubulin in ADPKD Pathogenesis
Session Information
- Cystic Kidney Diseases: Mechanisms and Models
October 25, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1201 Genetic Diseases of the Kidneys: Cystic
Authors
- Kavanaugh, Matthew A., The University of Kansas Medical Center, Kansas City, Kansas, United States
- Parnell, Stephen C., The University of Kansas Medical Center, Kansas City, Kansas, United States
- Slawson, Chad, The University of Kansas Medical Center, Kansas City, Kansas, United States
- Wallace, Darren P., The University of Kansas Medical Center, Kansas City, Kansas, United States
- Tran, Pamela Vivian, The University of Kansas Medical Center, 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 β-N-acetylglucosamine (O-GlcNAc) onto protein substrates by O-GlcNAc transferase (OGT) integrates multiple metabolic signals that are dysregulated in ADPKD. We have reported that protein O-GlcNAcylation is increased in kidneys of ADPKD patients and mouse models, and that genetic downregulation of O-GlcNAcylation markedly attenuates disease severity and extends mouse survival. To determine the underlying pathogenic mechanisms, we sought to identify proteins that are hyper-O-GlcNAcylated 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. Hyper-O-GlcNAcylated proteins were identified via immunoprecipitation and Western blot, after which sites were mapped via mass spectrometry with generation and analysis of relevant point mutants to follow.
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 survive beyond one year. In adult mice, deletion of Ogt in Pkd1 cko mice reduced renal cystogenesis and KW/BW. In P14 kidney extracts, hyper-O-GlcNAcylation of metabolic regulator, AMPKα1/α2, as well as of acetylated α-tubulin, which comprises the ciliary axoneme, was observed. In AMPKα1, Ser184 was identified as an O-GlcNAc site, adjacent to the activating phosphorylation site.
Conclusion
In PKD, protein O-GlcNAcylation, including of AMPK and acetylated α-tubulin, 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