EETs Attenuate Ox-LDL-Induced LTB4 Production and Activity by Inhibiting p38 MAPK Phosphorylation and 5-LO/BLT1 Receptor Expression in Rat Pulmonary Arterial Endothelial Cells

• Published in: PloS one 2015-06, Vol.10 (6), p.e0128278-e0128278
• Main Authors: Jiang, Jun-xia, Zhang, Shui-juan, Xiong, Yao-kang, Jia, Yong-liang, Sun, Yan-hong, Lin, Xi-xi, Shen, Hui-juan, Xie, Qiang-min, Yan, Xiao-feng
• Format: Article
• Language: English
• Subjects: 8,11,14-Eicosatrienoic Acid - analogs & derivatives; 8,11,14-Eicosatrienoic Acid - pharmacology; Acids; Animals; Arachidonate 5-lipoxygenase; Arachidonate 5-Lipoxygenase - chemistry; Arachidonate 5-Lipoxygenase - genetics; Arachidonate 5-Lipoxygenase - metabolism; Arachidonic acid; Atherosclerosis; Attenuation; Blotting, Western; Cell adhesion; Cells, Cultured; Cytochrome; Drugs; Endothelial cells; Endothelium; Hospitals; Inflammation; Inflammation - drug therapy; Inflammation - metabolism; Inflammation - pathology; Intercellular adhesion molecule 1; Kinases; Laboratory animals; Leukotriene B4; Leukotriene B4 - metabolism; Lipoproteins; Lipoproteins, LDL - pharmacology; Lipoxygenase; Low density lipoprotein; Male; MAP kinase; Medicine; Metabolism; Metabolites; Molecular chains; Monocyte chemoattractant protein; Monocyte chemoattractant protein 1; NF-κB protein; p38 Mitogen-Activated Protein Kinases - antagonists & inhibitors; p38 Mitogen-Activated Protein Kinases - genetics; p38 Mitogen-Activated Protein Kinases - metabolism; Permeability; Pharmaceutical sciences; Phosphorylation; Phosphorylation - drug effects; Protein kinase; Proteins; Pulmonary arteries; Pulmonary artery; Pulmonary Artery - cytology; Pulmonary Artery - drug effects; Pulmonary Artery - metabolism; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Receptors, Leukotriene B4 - antagonists & inhibitors; Receptors, Leukotriene B4 - genetics; Receptors, Leukotriene B4 - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; Rodents; Smooth muscle; Vasodilator Agents - pharmacology
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0128278

Cytochrome P-450 epoxygenase (EPOX)-derived epoxyeicosatrienoic acids (EETs), 5-lipoxygenase (5-LO), and leukotriene B4 (LTB4), the product of 5-LO, all play a pivotal role in the vascular inflammatory process. We have previously shown that EETs can alleviate oxidized low-density lipoprotein (ox-LDL)-induced endothelial inflammation in primary rat pulmonary artery endothelial cells (RPAECs). Here, we investigated whether ox-LDL can promote LTB4 production through the 5-LO pathway. We further explored how exogenous EETs influence ox-LDL-induced LTB4 production and activity. We found that treatment with ox-LDL increased the production of LTB4 and further led to the expression and release of both monocyte chemoattractant protein-1 (MCP-1/CCL2) and intercellular adhesion molecule-1 (ICAM-1). All of the above ox-LDL-induced changes were attenuated by the presence of 11,12-EET and 14,15-EET, as these molecules inhibited the 5-LO pathway. Furthermore, the LTB4 receptor 1 (BLT1 receptor) antagonist U75302 attenuated ox-LDL-induced ICAM-1 and MCP-1/CCL2 expression and production, whereas LY255283, a LTB4 receptor 2 (BLT2 receptor) antagonist, produced no such effects. Moreover, in RPAECs, we demonstrated that the increased expression of 5-LO and BLT1 following ox-LDL treatment resulted from the activation of nuclear factor-κB (NF-κB) via the p38 mitogen-activated protein kinase (MAPK) pathway. Our results indicated that EETs suppress ox-LDL-induced LTB4 production and subsequent inflammatory responses by downregulating the 5-LO/BLT1 receptor pathway, in which p38 MAPK phosphorylation activates NF-κB. These results suggest that the metabolism of arachidonic acid via the 5-LO and EPOX pathways may present a mutual constraint on the physiological regulation of vascular endothelial cells.