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Kidney Week

Abstract: TH-PO476

Rescue Mechanism for Glomerular Endothelial Lipid Metabolic Dysfunction in Alport Syndrome

Session Information

Category: Genetic Diseases of the Kidneys

  • 1202 Genetic Diseases of the Kidneys: Non-Cystic

Authors

  • Soloyan, Hasmik, Children's Hospital Los Angeles, Los Angeles, California, United States
  • Thornton, Matthew Edward, University of Southern California Keck School of Medicine, Los Angeles, California, United States
  • Clair, Geremy, Pacific Northwest National Laboratory, Richland, Washington, United States
  • Cuala, Janielle M., University of Southern California Keck School of Medicine, Los Angeles, California, United States
  • Zhang, Qi, Children's Hospital Los Angeles, Los Angeles, California, United States
  • Georgia, Senta K., Children's Hospital Los Angeles, Los Angeles, California, United States
  • Cravedi, Paolo, Icahn School of Medicine at Mount Sinai, New York, New York, United States
  • Da Sacco, Stefano, Children's Hospital Los Angeles, Los Angeles, California, United States
  • Perin, Laura, Children's Hospital Los Angeles, Los Angeles, California, United States
  • Sedrakyan, Sargis, Children's Hospital Los Angeles, Los Angeles, California, United States
Background

Glomerular endothelial dysfunction plays a key role in the development of chronic kidney disease (CKD). In Alport syndrome (AS, caused by mutations in collagen IVα3α4α5) damage to the glomerular endothelial cells (GEC) occurs before onset of heavy proteinuria and is characterized by altered fenestration size and glycocalyx deposition. Despite this evidence, the role of GEC in Alport progression is poorly understood. Here, we elucidate the role of lipids in GEC injury in an animal model of AS, and the potential of using amniotic fluid stem cell (AFSC) derived extracellular vesicles (EVs) as a rescue strategy to restore glomerular homeostasis.

Methods

The phasor approach to FLIM (fluorescent lifetime imaging microscopy) was applied to evaluate the metabolic changes in the kidneys (and particularty in the glomeruli and GEC) of AS and WT mice. GEC isolated by FACS from tdTomato-reporter AS and WT mice at 4-months of age were compared by bulk RNA-seq and lipidomics. In vitro, silencing experiments on primary human GEC were performed to study the role of fatty acid synthase (FASN) in GEC metabolic dysfunction. FASN-carrying AFSC-EVs and control nanoparticles were applied both in vitro and in vivo to restore lipid homeostasis in GEC.

Results

In AS mice, RNAseq analysis of GEC revealed changes in the metabolic genes, (including FASN) and pathways associated with uptake, synthesis and oxidation of fatty acids. FLIM studies showed that changes in the metabolic fingerprint of the GEC correlated with increasing age and severety of disease in AS mice. Lipidome analysis found high abundance of triglycerides in GEC isolated from AS. We confirmed accumulation of lipid droplets in the glomeruli of AS mice, as well as in FASN KO human primary GEC, in vitro. These results suggest potential mitochondrial dysfunction in GEC. AFSC-EVs treatment restored lipid homeostasis in GEC, both in vitro and in vivo.

Conclusion

We report for the first time a lipid metabolic dysfunction in Alport GEC, and the ability of AFSC-EVs to rescue this phenotype. Therefore, better understanding of the role of GEC in AS could lead to the development of targeted new therapies for the treatment of this and other forms of CKD.

Funding

  • Private Foundation Support