Results
To test our hypothesis, ACE-2 expression was evaluated in cultured HUVECs treated with clinically relevant dose 5mM of VPA[19, 21] for 24 hours. HUVECs represent the standard cellular model to study endothelial cells in vitro .[19, 20, 22] Our qPCR data demonstrated a significant ~70% reduction in the expression level of ACE-2 in VPA-treated ECs in comparison to control ECs (Fig. 1A ). Given the venous nature of HUVECs, we next evaluated the expression level of ACE-2 in an arterial ECs by treating cultured HCAECs with 5mM of VPA for 24 hours. Similar to HUVECs, we observed a significant ~70% reduction in the ACE-2 expression in VPA-treated in comparison to vehicle-treated control HCAECs (Fig. 1B ). To assess dose-response effect of higher dose of VPA on endothelial ACE-2 expression, we treated HUVECs with 10mM and 20mM of VPA for 24 hours and evaluated ACE-2 expression. Our qPCR data showed a significant reduction in ACE-2 expression for both 10 mM and 20 mM of VPA but there was no difference in ACE-2 expression between 10 and 20 mM of VPA treated ECs. Next, we evaluated the effect of VPA on pro-inflammatory IL-6 expression, and endothelial activation marker ICAM-1 expression. We observed a significant down-regulation of IL-6 following 5mM of VPA treatment to HUVECs in comparison to control (Fig. 1C, D ). Interestingly, VPA also significantly reduced ICAM-1 expression in VPA-treated in comparison to control ECs (Fig. 1E ).