Background:

Polyphenols exert antiinflammatory, vasoprotective properties and are known as potent CFTR activators. Previous experiments have shown, that WS 1442, a polyphenol-rich extract from hawthorn (Crataegus spp.), induces a swelling of the endothelial surface layer (ESL). In this study, we investigated whether the treatment of endothelial cells with specifically selected polyphenols swells the ESL and whether this swelling is CFTR dependent.

Methods:

The nanomechanical properties of the ESL of living endothelial GM 7373 cells were monitored by atomic force microscopy before and after treatment with resveratrol, quercetin and (-)-epicatechin, respectively. In addition, we performed similar experiments in presence of the Cl^--channel blockers NPPB and CFTR Inh172. Since cortical actin is involved in CFTR regulation we studied also the impact of the polyphenols on cortical actin.

Results:

Our data reveal that polyphenols lead to a dose-dependent swelling of the ESL within minutes. In parallel, cortical stiffness decreased. The swelling of the ESL, but not the change in cortical stiffness was prevented when CFTR was blocked prior to polyphenol treatment. The polyphenol-induced swelling of the ESL could be mimicked by the cortical actin depolymerizing agent cytochalasin D.

Conclusion:

Polyphenols induce ESL-swelling by activation of CFTR through depolymerization of cortical actin. ESL swelling could explain some of the vasoprotective properties of these polyphenols.