Abstract: FR-PO722
Ezetimibe Restores the Communication Between Lipid Droplets and Mitochondria via Modulation of Plin5
Session Information
- Glomerular Diseases: Podocyte Biology - I
November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1304 Glomerular Diseases: Podocyte Biology
Authors
- Kim, Jin Ju, University of Miami School of Medicine, Miami, Florida, United States
- Molina David, Judith T., Washington University in St Louis School of Medicine, St Louis, Missouri, United States
- Fontanesi, Flavia, University of Miami School of Medicine, Miami, Florida, United States
- Miner, Jeffrey H., Washington University in St Louis School of Medicine, St Louis, Missouri, United States
- Merscher, Sandra M., University of Miami School of Medicine, Miami, Florida, United States
- Fornoni, Alessia, University of Miami School of Medicine, Miami, Florida, United States
Background
Alport Syndrome (AS) is a hereditary disease caused by mutations in collagen type IV. Pathogenic renal lipid droplets (LD) and triglyceride (TG) accumulation have been demonstrated in experimental AS (Col4a3KO mice). FFA catabolism resulting from excessive lipolysis of TG is a major contributor to cell lipotoxicity. Perilipin 5 (PLIN5) is an LD-related protein that plays a critical role in regulating TG lipase activity and the interactions between LD and mitochondria, where it protects mitochondria from excessive exposure to FFA. Here we test the hypothesis that PLIN5 expresses in podocytes and that PLIN5 deficiency in AS causes excessive TG breakdown and the loss of LD-mitochondrial contact, thus contributing to kidney failure
Methods
In vitro, Immortalized AS podocytes and WT podocytes were established and characterized in our laboratory by breeding the Col4a3KO mice (Jackson Laboratory) to H-2kb-tsA58 transgenic mice (Charles River). PLIN5 expression was determined by RT-PCR and western blot analysis in podocytes from Col4a3KO mice when compared to controls. TG lipolysis and FFA quantification were determined and normalized to protein content. LD-Mitochondrial contact was determined by TEM analysis. PLIN5 expression was studied in kidney cortexes, and the effect of Ezetimibe on PLIN5 modulation, on LD-Mitochondrial contact and on podocyte injury was studied in vitro and in vivo.
Results
We demonstrate that PLIN5 is expressed in podocytes, and the expression of PLIN5 is significantly decreased in AS podocytes compared to WT podocytes (p<0.01). AS podocytes also showed significantly increased rates of TG lipolysis (p<0.05), intracellular free fatty acids (p<0.05) and apoptosis (p<0.01) when compared to WT podocytes. AS podocytes had reduced number of LD-mitochondrial contacts (p<0.05), implying that and apoptosis. Moreover, Ezetimibe, which restored LD-Mitochondrial contact in vitro (p<0.05) and improved kidney function in vivo, was found to restore PLIN5 expression in vitro and in vivo (p<0.05).
Conclusion
PLIN5 deficiency in AS podocytes causes excessive TG lipolysis and inefficient FA transfer from LD to Mitochondria, leading to mitochondrial dysfunction. Ezetimibe improves LD-mitochondria communication via restoring PLIN5 expression.
Funding
- NIDDK Support