Abstract for presentation at Australia and New Zealand Society of Nephrology Annual Scientific Conference

Background: The Notch signalling pathway is recognised to be involved cell differentiation, particularly in embryogenesis. As cells undergoing epithelial to mesenchymal transformation (EMT) are known to re-express fetal markers, the role of the Notch signalling pathway in EMT in proximal tubular cells was assessed
Aim: The aim of this study was to assess the role of the Notch signalling in proximal tubular epithelial cells (PTECs) after induction of epithelial to mesenchymal transformation (EMT).
Methods: Primary cultures of PTECs were exposed to a combination of 10 ng/ml transforming growth factor beta (TGFβ) and Angiotensin II (AngII) for 72 hrs to induce EMT. Markers of EMT, Notch expression and inhibition of Notch activation were determined and results expressed as a percentage of control values.
Results: After EMT induction, E-cadherin decreased significantly (46.3±7.2%; P=0.0001), a-smooth muscle actin (aSMA) increased (140.5±2.1%; P<0.05), matrix metalloproteases MMP-2 and MMP-9 increased (5250+200%; P<0.05 and 1900+70%; P<0.05 respectively), and an increase in Notch expression was observed (122.5±4.5%; P<0.0001) compared to cells exposed to control conditions. After inhibition of Notch activation using DAPT, the decrease in E-cadherin expression was attenuated (74.5±3.4%; P<0.05), a-SMA expression returned to control values (104.74±0.9%; P=NS) and the observed increase in MMP-2 and -9 production in cells undergoing EMT was reversed.
Conclusion: PTECs when induced to undergo EMT increase Notch expression and inhibition of Notch signalling inhibits EMT. These results suggest a direct role for the Notch signalling pathway in the development of EMT.