Eicosapentaenoic acid reduces pulmonary endothelial inflammation caused by cytokine treatment

ABSTRACT

INTRODUCTION: Infectious agents like SARS-CoV-2 can cause endothelial cell (EC) dysfunction in multiple vascular beds from different organs in infected patients, including pulmonary tissue that leads to acute respiratory distress syndrome (ARDS). The omega-3 fatty acid eicosapentaenoic acid (EPA) has multifactorial effects that lead to reduced inflammation and improved EC function. These benefits of EPA may contribute to reduced cardiovascular events as reported in REDUCE-IT. EPA is currently being tested in patients at risk for COVID-19 in multiple trials. This study tested the effects of EPA on protein expression in human pulmonary ECs under conditions of inflammation using the cytokine IL-6 to simulate viral infection conditions. METHODS: Human lung microvascular endothelial cells (HMVEC-L) were pretreated with vehicle or EPA (40 μM) in 2% FBS for 2 h, then challenged with IL-6 at 12 ng/ml for 24 h. Proteomic analysis of cell lysates was performed using LC/MS to capture relative expression levels of over 1,000 proteins. Only significant changes in protein expression between treatment groups >2-fold were analyzed. Specific pathway analysis was carried out using gene set enrichment analysis (GSEA). Expression levels of intercellular adhesion molecule-1 (ICAM-1) were measured by Western blot analysis. RESULTS: HMVEC-L pretreated with EPA and then challenged with IL-6 showed reduced release of >60 proteins compared with untreated controls. Among the proteins significantly suppressed were those involved in inflammation, including protein LYRIC, integrin alpha-5, peroxiredoxin-1, macrophage migration inhibitory factor, and lysine-tRNA ligase. GSEA analysis revealed changes in several pathways related to transcription regulation. Exposure to IL-6 also caused a >5-fold increase in ICAM-1 expression compared with vehicle (p<0.001). EPA reduced ICAM-1 expression compared with control by 41% (p<0.05). CONCLUSIONS: These findings indicate that EPA reduces the expression of multiple inflammatory proteins triggered by cytokine treatment. These studies support a broad antiinflammatory effect of EPA on pulmonary ECs that may have therapeutic implications for patients at risk for influenza or SARS-CoV-2 or other pro-inflammatory stimuli.