Abstract: TH-PO373

Aldosterone-Induced Epithelial-to-Mesenchymal Transition (EMT) in Peritoneal Mesothelial Cells: Differential Role of NADPH Oxidase and Mitochondrial Dysfunction

Session Information

Category: Cell Biology

  • 201 Cell Signaling, Oxidative Stress

Authors

  • Kang, Duk-Hee, Ewha University College of Medicine, Seoul, Korea (the Republic of)
  • Ryu, Eun sun, Ewha Womans University School of Medicine, Seoul, Korea (the Republic of)
  • Kim, Dal-ah, Ewha Womans University Medical Center, Seoul, SEOUL, Korea (the Republic of)
  • Kang, Hyun-Jung, Ewha Womans University, Seoul, Korea (the Republic of)
Background

Peritoneal fibrosis is one of the major causes of technical failure in patients on peritoneal dialysis. Epithelial-to-mesenchymal transition (EMT) of peritoneum has been known as an early and reversible mechanism of peritoneal fibrosis. Human peritoneal mesothelial cell (HPMC) is known to have its own renin-angiotensin-aldosterone system (RAAS), however it has not been investigated whether aldosterone, an end product of RAAS induces EMT in HPMC and which mechanisms are responsible for aldosterone-induced EMT

Methods

EMT of HPMCs was evaluated by comparing the expression of epithelial cell marker, E-cadherin and mesenchymal cell marker, α-smooth muscle actin (α-SMA) after the stimulation with aldosterone (1-100 nM) or spironolactone. Activation of Src, epidermal growth factor receptor (EGFR), phosphoinositide 3-kinase (PI3K), Akt and generation of reactive oxygen species (ROS) were assessed by Western blotting, DCF-DA and Mito-SOX staining. Effect of kinase inhibitors or anti-oxidants (N-acetyl cysteine, DPI, and MitoQ) on aldosterone-induced EMT was evaluated.

Results

Aldosterone induced EMT in cultured HPMC, which was blocked by spironolactone. Aldosterone induced an activation of both Src and EGFR from 15 and 30 minutes, followed by an activation of PI3K and Akt from 1 and 3 hours, respectively. The inhibitors of Src (PP2, 5 uM) and EGFR (Erlotinib, 10 uM) alleviated aldosterone-induced EMT. Aldosterone induced ROS in HPMCs from 5 minutes with an increase in NOX activity and NOX-1, -2, -4 mRNA expression. Aldosterone also increased mitochondrial ROS production. Anti-oxidant treatment ameliorated the aldosterone-induced EMT. NAC an DPI alleviated an activation of Src/EGFR and PI3K/Akt pathways whereas mitoQ did not alter the phosphorylation of EGFR and PI3K in HPMCs

Conclusion

Aldosterone induced EMT in HPMC by acting through mineralocorticoid receptor. Aldosterone-induced generation of ROS followed by an activation of Src/EGFR and PI3K/Akt pathways served as the mechanism of aldosterone-induced EMT of HPMC via differential regulation of NOX and mitochondrial ubiquitone