Background: Fibrosis results in excessive buildup of extracellular matrix proteins along with abnormalities in structure and is partly derived by a process involving transforming growth factor β (TGF-β) called endothelial-to-mesenchymal transition (EndMT). We investigated whether the aldosterone receptor-blocker spironolactone could abrogate TGF-β-induced fibrosis in EndMT and the underlying mechanism.
Methods: Human umbilical vein endothelial cells (HUVECs) were divided into 5 groups for treatment: blank; vehicle control; TGF-β (10 ng/ml); spironolactone (1 μM)+TGF-β; and spironolactone+TGF-β+DAPT (10 μM). Cell chemotaxis was assayed by transwell assay. The expression of CD31 and vimentin was determined by Immunofluorescence staining and western blot analysis. Notch1 protein level was detected by western blot analysis.
Results: Spironolactone significantly prevented TGF-β-stimulated EndMT by down-regulate vimentin and up-regulate CD31 in HUVECs (p<0.01).It inhibited cell migration during EndMT (p<0.01). The protective effect of spironolactone against EndMT could be attenuated by blocking the Notch signal pathway with DAPT (p<0.01). Notch signaling was activated and cross-interacted with TGF-β and spironolactone in regulating EndMT in HUVECs and reversed the spironolactone-related signaling by abrogating the antifibrotic actions with decreased Notch1 protein expression (p<0.01).
Conclusion: Spironolactone may have a protective role in TGF-β-induced EndMT in HUVECs mediated by the Notch signal pathway.