Does EPA Cause A Decrease in Inflammation of bEnd.3 Cells Through FFAR4?

Abstract

Atherosclerosis is an inflammatory disease initiated by low and oscillatory shear stress on the endothelium. The inflammatory process recruits leukocytes to the vessel wall by expression of the adhesion molecule VCAM-1. Activation of the NF-κB inflammatory signaling pathway is responsible for the increase in VCM-1 expression. Omega 3 FAs, such as EPA, reduce the risk of atherosclerosis by decreasing this inflammatory response. The pathway by which omega 3 FAs is proposed to inhibit inflammation includes activating FFAR4 to decrease NF-κB activation thereby reducing expression of adhesion molecules. We hypothesized that treatment of endothelial cells with 30 μM EPA would decrease inflammation via activating FFAR4. We evaluated the changes in 2 signaling molecules (IκB and pIKK) and VCAM-1 expression in bEnd.3 cells. Endothelial cells were treated with 30 μM EPA for 24 hours and showed an early decrease in inflammation (0.5 hours; based upon inflammatory signaling molecules) followed by an increase in inflammation after 24 hours. To evaluate if FFAR4 was mediating this response, bEnd.3 cells were treated with 10 μM TUG-891. Treatment with the FFAR4 agonist decreased pIKK at 24 hours suggesting a decrease in the inflammatory response, however, VCAM-1 expression was not changed. The addition of 10 μM of the FFAR4 antagonist AH-7614, increased inflammation (1.5 hours) which was followed by a decrease (24 hours). This response mirrored that of EPA treatment suggesting that AH-7614 is acting as an agonist to FFAR4 (or is affecting inflammation through another pathway). Further experiments are required to understand the role of FFAR4 in mediating the anti-inflammatory response to EPA