[Free Radical Biology and Medicine] 349 – Role of the Glycocalyx in Fluid Shear Stress Modulation of
Fluid shear stress (FSS) elicits a haemodynamic force on endothelial cells (EC), which can modulate their redox phenotype. Nuclear factor E2-related factor 2 (Nrf2), a transcription factor that regulates antioxidant gene expression, is enhanced in response to US1 or treatment with sulphoraphane (SFN)2, an isothiocyanate derived from cruciferous vegetables. The EC glycocalyx (GCX) maintains cellular homeostasis and is reduced in models of atherosclerosis and in EC exposed to disturbed FSS3. Disruption of the GCX leads to impaired FSS-mediated nitric oxide production4, highlighting its role in mechanotransduction. This study investigates the effects GCX disruption on SFN or FSS-mediated induction of heme oxygenase-1, an antioxidant defence enzyme that catabolizes the pro-oxidant heme to biliverdin and vasodilator carbon monoxide. Human umbilical vein EC were subjected to FSS (unidirectional, 15 dyn/cm2, 8h) in microfluidic slides (Ibidi, GmbH). The GCX components, heparan sulphate (HS) and sialic acid (SA) were assessed by immunofluorescence and HO-1 expression was assessed by western blotting. HO-1 levels were significantly up-regulated by FSS compared to static cultures. To remove HS or SA, cells were treated with heparinase III (HepIII, 50mU/ml for 2h) or Neuraminidase (Neur, 2U/ml for 30min) respectively prior to exposure to FSS or treatment with SFN (5μM, 8h) or vehicle (DMSO, 0.01% v/v) in static conditions. HO-1 induction by both FSS or SFN was significantly attenuated by Neur, whereas HepIII only diminished SFN-mediated augmentation of HO-1. Taken together, these findings demonstrate that the GCX is involved in HO-1 induction by FSS or SFN in EC, thus strategies to enhance expression of GCX components may promote an antioxidant EC phenotype in regions prone to atherogenesis where the GCX is damaged.
Paraskevi-Maria Psefteli1, Mark Fowler2, Richard Draijer3, Giovanni E. Mann1, Richard Siow1 1 Cardiovascular Division, King's College London, UK 2 Strategic Science Group, Unilever R&D, Colworth, UK 3 Strategic Science Group, Unilever R&D, Vlaardingen, Netherlands
Volume 100, Supplement, November 2016, Pages S148