title: 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.
abstract: 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.
authors.affiliation: The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
authors.forename: Jun-xia
authors.initials: JX
authors.lastname: Jiang
authors.affiliation: College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China.
authors.forename: Shui-juan
authors.initials: SJ
authors.lastname: Zhang
authors.affiliation: College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China.
authors.forename: Yao-kang
authors.initials: YK
authors.lastname: Xiong
authors.affiliation: Zhejiang Respiratory Drugs Research Laboratory of China FDA, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
authors.forename: Yong-liang
authors.initials: YL
authors.lastname: Jia
authors.affiliation: Zhejiang Respiratory Drugs Research Laboratory of China FDA, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
authors.forename: Yan-hong
authors.initials: YH
authors.lastname: Sun
authors.affiliation: Zhejiang Respiratory Drugs Research Laboratory of China FDA, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
authors.forename: Xi-xi
authors.initials: XX
authors.lastname: Lin
authors.affiliation: The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
authors.forename: Hui-juan
authors.initials: HJ
authors.lastname: Shen
authors.affiliation: Zhejiang Respiratory Drugs Research Laboratory of China FDA, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
authors.forename: Qiang-min
authors.initials: QM
authors.lastname: Xie
authors.affiliation: The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
authors.forename: Xiao-feng
authors.initials: XF
authors.lastname: Yan
mesh_terms: D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D002478:Cells, Cultured; D007249:Inflammation / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D007975:Leukotriene B4 / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D008297:Male; D010766:Phosphorylation / Q000187:drug effects; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D018102:Receptors, Leukotriene B4 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014665:Vasodilator Agents / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: C513240:LTB4R protein, human; D008077:Lipoproteins, LDL; D012333:RNA, Messenger; D018102:Receptors, Leukotriene B4; D014665:Vasodilator Agents; C099252:oxidized low density lipoprotein; D007975:Leukotriene B4; C046782:14,15-epoxy-5,8,11-eicosatrienoic acid; D001094:Arachidonate 5-Lipoxygenase; D048051:p38 Mitogen-Activated Protein Kinases; D015126:8,11,14-Eicosatrienoic Acid