Enhanced 15-HPETE production during oxidant stress induces apoptosis of endothelial cells.
Oxidant stress plays an important role in the etiology of vascular diseases by increasing rates of endothelial cell apoptosis, but few data exist on the mechanisms involved. Using a unique model of oxidative stress based on selenium deficiency (-Se), the effects of altered eicosanoid production on bovine aortic endothelial cells (BAEC) apoptosis was evaluated. Oxidant stress significantly increased the immediate oxygenation product of arachidonic acid metabolized by the 15-lipoxygenase pathway, 15-hydroxyperoxyeicosatetraenoic acid (15-HPETE). Treatment of -Se BAEC with TNFalpha/cyclohexamide (CHX) exhibited elevated levels of apoptosis, which was significantly reduced by the addition of a specific 15-lipoxygenase inhibitor PD146176. Furthermore, the addition of 15-HPETE to PD146176-treated BAEC, partially restored TNF/CHX-induced apoptosis. Increased exposure to 15-HPETE induced apoptosis, as determined by internucleosomal DNA fragmentation, chromatin condensation, caspase-3 activation, and caspase-9 activation, which suggests mitochondrial dysfunction. The expression of Bcl-2 protein also was decreased in -Se BAEC. Addition of a caspase-9 inhibitor (LEHD-fmk) completely blocked 15-HPETE-induced chromatin condensation in -Se BAEC, suggesting that 15-HPETE-induced apoptosis is caspase-9 dependent. Increased apoptosis of BAEC as a result of oxidant stress and subsequent production of 15-HPETE may play a critical role in a variety of inflammatory based diseases.
Sordillo
Lorraine M
LM
Large Animal Clinical Sciences, D202 Veterinary Medical Center, College of Veterinary Medicine, Michigan State University, East Lansing, 48824-1314, USA. sordillo@msu.edu
Weaver
James A
JA
Cao
Yu-Zhang
YZ
Corl
Chris
C
Sylte
Matt J
MJ
Mullarky
Isis K
IK
D000818:Animals; D017209:Apoptosis; D001093:Arachidonate 15-Lipoxygenase / Q000378:metabolism; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000378:metabolism; D015289:Leukotrienes / Q000096:biosynthesis*; D008054:Lipid Peroxides / Q000096:biosynthesis*; D018384:Oxidative Stress; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012643:Selenium / Q000378:metabolism
D015289:Leukotrienes; D008054:Lipid Peroxides; D019253:Proto-Oncogene Proteins c-bcl-2; C025086:15-hydroperoxy-5,8,11,13-eicosatetraenoic acid; D005979:Glutathione Peroxidase; D001093:Arachidonate 15-Lipoxygenase; D053453:Caspase 9; D020169:Caspases; D012643:Selenium