Dietary γ-glutamyl valine (γ-EV) ameliorates TNF-α induced vascular inflammation via endothelial calcium-sensing receptor (CaSR)

γ-glutamyl valine (γ-EV), commonly found in edible beans, was shown to reduce gastrointestinal inflammation via activation of calcium-sensing receptor (CaSR). The present study aimed to evaluate the efficacy of γ-EV in modulating the TNF-α induced inflammatory responses in endothelial cells via CaSR mediated pathways. Human aortic endothelial cells (HAoECs) were pre-treated (2 h) with γ-EV (0.01, 0.1, and 1 mM). 1 mM pre-treatment of γ-EV significantly reduced the upregulation of inflammatory adhesion molecules, VCAM-1 and E-Selectin, by 44.56% and 57.41% respectively. Cytokines IL-8 and IL-6, production was significantly reduced by 40% and 51%, respectively with 1 mM pre-treatment of γ-EV. Similarly, there was a significant reduction in chemokine MCP-1 from a positive control of 9.70 ± 0.52 ng/mL to 6.6 ± 0.43 ng/mL, after γ-EV treatment. The anti-inflammatory effect of γ-EV was attenuated by the treatment of CaSR specific inhibitor, NPS-2143, suggesting the involvement of CaSR mediated pathways. Further studies identified the critical role of key modulators, such as β-arrestin2 and CREB, in mediating the CaSR-dependent anti-inflammatory effect of γ-EV. Lastly, the transport efficiency of γ-EV was evaluated through the monolayer of intestinal epithelial cells (Caco-2) and the apparent permeability (Papp) of the peptide was found to be 1.56x10-6 cm/sec.