INTRODUCTION: SARS-CoV-2 and other viruses can cause endothelial cell (EC) dysfunction in multiple vascular beds, including pulmonary tissue. Infected patients may then develop acute respiratory distress syndrome (ARDS) and cardiovascular (CV) complications. The omega-3 fatty acid eicosapentaenoic acid (EPA) and its bioactive metabolites favorably modulate inflammation and EC function. These benefits of EPA may contribute to reduced CV events as reported in outcome trials (REDUCE-IT). Currently, EPA is being tested in patients with or at risk for COVID-19. This study tested the effects of either EPA pre- or post-treatment on global protein expression in human pulmonary ECs under conditions of inflammation using the cytokine IL-6 to simulate conditions of advanced viral infections. METHODS: Human lung microvascular endothelial cells (HMVEC-L) were pre-treated with either EPA (40 μM) or IL-6 (12 ng/mL) for 2 hr and then treated with IL-6 or EPA, respectively, for 24 hr in media with 2% FBS. Proteomic analysis was performed using LC/MS to assess relative protein expression levels. Only significant (p< 0.05) changes in protein expression between treatment groups >1-fold were analyzed. Expression of soluble intercellular adhesion molecule-1 (sICAM-1) was separately measured with immunochemistry. RESULTS: HMVEC-L pre- and post-treated with EPA during challenge with IL-6 showed significant changes in 100 (49/51 up/down) and 441 (229/212 up/down) proteins, respectively, compared with IL-6 treatment alone. Among the 31 proteins that were significantly modulated by both EPA pre- and post-treatment, thioredoxin reductase 1 increased relative to IL-6 alone, while matrix metalloproteinase 1 and fibronectin both decreased. Other proteins, such as hypoxia up-regulated protein 1, were differentially modulated by EPA relative to IL-6 (increased in pre-treatment, decreased in post-treatment). Finally, EPA significantly reduced sICAM- 1expression by 41% and 12% compared with IL-6 alone in the pre- and post-treatment models, respectively. CONCLUSIONS: These findings indicate that EPA favorably modulates the expression of multiple inflammatory and cytoprotective proteins during inflammation. These studies support a broad anti-inflammatory effect of EPA on pulmonary ECs that may have therapeutic implications for patients at risk for ARDS due to infectious agents including SARS-CoV-2 or other viruses.
Eicosapentaenoic acid favorably modulates protein expression in pulmonary endothelial inflammation