EICOSAPENTAENOIC ACID REDUCES EXPRESSION OF PLATELET ACTIVATION AND AGGREGATION PROTEINS IN PULMONARY AND VASCULAR ENDOTHELIUM DURING INFLAMMATION

Abstract

BACKGROUND Atherothrombotic cardiovascular (CV) disease leads to platelet aggregation and thrombus formation. Icosapent ethyl is an ethyl ester of eicosapentaenoic acid (EPA), and was shown to reduce ischemic events in high-risk patients (REDUCE-IT). IPE is approved by Health Canada to reduce CV risk among patients with elevated TG levels as an add-on to maximally tolerated statin therapy. In this study, the effects of EPA on expression of proteins associated with platelet activation and aggregation were measured in cytokine (IL-6) treated pulmonary and vascular endothelial cells (ECs). METHODS AND RESULTS Human pulmonary ECs (PECs) and umbilical vein ECs (HUVECs) were treated with vehicle or EPA (40/10 µM in PECs/HUVECs) and IL-6 (12 ng/mL) for 24 h. Proteomic analysis was performed using liquid chromatography/mass spectroscopy that detected modulation of >1,000 proteins. Proteins which showed significantly (p < 0.05) greater than 1-fold change between treatment groups were further assessed. EPA significantly downregulated a total of 36 proteins involved in platelet activation, signaling, aggregation, in EC following cytokine exposure. Platelet endothelial cell adhesion molecule (PECAM) was downregulated in both HUVECs and PECs (1.2-fold) by EPA. In PECs, EPA significantly modulated 26 additional proteins related to platelet activation, including amyloid-beta precursor protein (1.1-fold decrease) and thrombin receptor (PAR-1,1.3-fold decrease). In HUVECs, the expression of nine other proteins were modulated related to platelet activation, including superoxide dismutase (1.6-fold increase). CONCLUSION EPA significantly reduced expression of multiple EC proteins required for platelet activation and aggregation, including PECAM in both pulmonary and vascular tissues. These findings indicate potential novel anti-platelet mechanisms for EPA that may account for reduced ischemic events in REDUCE-IT. Atherothrombotic cardiovascular (CV) disease leads to platelet aggregation and thrombus formation. Icosapent ethyl is an ethyl ester of eicosapentaenoic acid (EPA), and was shown to reduce ischemic events in high-risk patients (REDUCE-IT). IPE is approved by Health Canada to reduce CV risk among patients with elevated TG levels as an add-on to maximally tolerated statin therapy. In this study, the effects of EPA on expression of proteins associated with platelet activation and aggregation were measured in cytokine (IL-6) treated pulmonary and vascular endothelial cells (ECs). Human pulmonary ECs (PECs) and umbilical vein ECs (HUVECs) were treated with vehicle or EPA (40/10 µM in PECs/HUVECs) and IL-6 (12 ng/mL) for 24 h. Proteomic analysis was performed using liquid chromatography/mass spectroscopy that detected modulation of >1,000 proteins. Proteins which showed significantly (p < 0.05) greater than 1-fold change between treatment groups were further assessed. EPA significantly downregulated a total of 36 proteins involved in platelet activation, signaling, aggregation, in EC following cytokine exposure. Platelet endothelial cell adhesion molecule (PECAM) was downregulated in both HUVECs and PECs (1.2-fold) by EPA. In PECs, EPA significantly modulated 26 additional proteins related to platelet activation, including amyloid-beta precursor protein (1.1-fold decrease) and thrombin receptor (PAR-1,1.3-fold decrease). In HUVECs, the expression of nine other proteins were modulated related to platelet activation, including superoxide dismutase (1.6-fold increase). EPA significantly reduced expression of multiple EC proteins required for platelet activation and aggregation, including PECAM in both pulmonary and vascular tissues. These findings indicate potential novel anti-platelet mechanisms for EPA that may account for reduced ischemic events in REDUCE-IT.