Abstract 19392: Endothelial Knockout of Polycystin 1 (PC1) Alters Mitochondrial Functions and Bioenergetics
Polycystin 1 (PC1) is a mechanosensitive component of shear stress sensing in endothelial cells. Shear stress is a critical determinant of endothelial proliferation, migration and differentiation, which are energy dependent processes. Since, mutations in PC1 impair shear-induced endothelial functions, we hypothesized PC1 may mediate its effects through mitochondrial-dependent energy production. In the present study, we measured mitochondrial function using the Seahorse XF24-3 flux analyzer in wild type and PC1 null endothelial cells. We found that the maximal oxygen consumption rate (OCR) and extracellular acidification rate (glycolysis) (ECAR) were 2-fold lower in PC1 null cells compared to Wt (p<0.05) in response to the mitochondrial uncoupler, FCCP (0.5 µmol/L). PC1 null cells also exhibited a 10-fold reduction in bioenergetic reserve capacity (p<0.05), indicating a severe mitochondrial dysfunction. Further, we found these cells show a 3.5-fold decrease in peroxisome proliferator-activated receptors gamma (PPAR gamma) coactivator-1 alpha (PGC-1 alpha) and a 4-fold decrease in the mitochondrial uncoupling protein 2 (UCP2) expression. Importantly, the mutant cells showed a 2-fold increase in the mitochondrial membrane potential as measured by a selective mitochondrial potential indicator, JC-1. Finally, we found that PC1 null cells showed an increased production of ROS as assessed by DHE and Mitosox staining. Importantly, there were no changes in mitochondrial abundance between PC1 and WT cells. Taken together, these results indicate the absence of PC1 impairs mitochondrial function and may contribute to the endothelial dysfunction observed in polycystic kidney disease (PKD).
- © 2012 by American Heart Association, Inc.