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Abstract: FR-PO321

Extracellular Vesicles Rescue Alport Glomerular Endothelial Lipid Dysfunction

Session Information

Category: Genetic Diseases of the Kidneys

  • 1102 Genetic Diseases of the Kidneys: Non-Cystic

Authors

  • Sedrakyan, Sargis, Children's Hospital Los Angeles Department of Pediatrics, Los Angeles, California, United States
  • Soloyan, Hasmik, Children's Hospital Los Angeles Department of Pediatrics, Los Angeles, California, United States
  • Thornton, Matthew Edward, University of Southern California, Los Angeles, California, United States
  • Cravedi, Paolo, Icahn School of Medicine at Mount Sinai, New York, New York, United States
  • Angeletti, Andrea, IRCCS Istituto Giannina Gaslini, Genoa, Italy
  • Perin, Laura, Children's Hospital Los Angeles Department of Pediatrics, Los Angeles, California, United States
Background

Glomerular endothelial dysfunction plays a key role in the development of chronic kidney disease (CKD), however, its role in Alport syndrome (AS, a kidney disorder characterized by mutations in collagen IVα3α4α5) progression has been elusive and understudied. We have previously shown that glomerular endothelial cell (GEC) injury is an early event that precedes podocyte damage in AS, manifested by enlarged fenestrations, altered glycocalyx and re-expression of GEC injury marker, plasmalemma vesicle associated protein (PLVAP). Here, we report on the link between altered lipid metabolism and GEC injury in AS, and the use of extracellular vesicles derived from amniotic fluid stem cells (AFSC-EVs) as a rescue strategy to re-establish lipid homeostasis.

Methods

GEC were isolated from tdTomato-reporter AS (Col4a5 mutantion on C57BL/6 background) and WT mice at 4 months of age by FACS and transcriptome was analyzed and compared by bulk RNA-seq. Kidney tissue from patients affected by AS were used to confirm our findings by spatial transcriptomics and histology. In vitro, silencing experiments using human primary GEC were used to study the role of fatty acid synthase (FASN) loss in GEC dysfunction. AFSC-EVs (which contain FASN in their cargo) were applied as a rescue strategy to normalize FASN expression and restore lipid homeostasis. Data were confirmed using AFSC-EV FASN-/-.

Results

AS GEC were highly enriched for differentially expressed genes associated with cellular lipid metabolism. Genes associated with fatty acid transport (CD36, FATP-1, Fabp3) and synthesis (FASN) among others were downregulated, which was further associated with glomerular accumulation of lipid droplets in mice and onset of heavy proteinuria. Spatial transcriptional profiling of glomeruli from AS patients revealed strong correlation between GEC specific markers and lipid metabolism associated genes, confirming our findings in human. In vitro, AFSC-EVs were able to rescue FASN deficiency and improve GEC function, unlike AFSC-EV FASN-/-.

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 functional 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