Prostacyclin inhibits endothelial cell XIAP ubiquitination and degradation.
To understand the role of prostacyclin (PGI(2)) in protecting endothelial cells from apoptosis, we evaluated the effects of carbaprostacyclin (cPGI(2)) on H(2)O(2)-induced human umbilical vein endothelial cell (HUVEC) apoptosis. cPGI(2) suppressed H(2)O(2)-induced annexin V-positive cells in a concentration- and time-dependent manner. Pre-treatment of HUVEC with 50 microM cPGI(2) for 4 h produced the maximal anti-apoptotic effect. Authentic PGI(2) generated by adenoviral transfer of PGI(2) synthetic genes exerted a similar protective effect. cPGI(2) inhibited Smac/DIABLO release from mitochondria, caspase 3 activation, focal adhesion protein degradation, and cell detachment. cPGI(2) selectively protected X-linked inhibitor of apoptosis protein (X-linked IAP, XIAP) from H(2)O(2)-induced ubiquitination, and preserved XIAP protein levels. PD-98059 but not H-89 abrogated the protective action of cPGI(2). cPGI(2) increased ERK phosphorylation which was blocked by PD-98059. HUVEC stably transfected with dominant negative Ras abrogated XIAP preservation by cPGI(2) while constitutive active Ras increased ERK phosphorylation and protected XIAP from degradation. Our results demonstrate for the first time that PGI(2) inhibits XIAP ubiquitination and degradation via the Ras/MEK-1/ERK signaling pathway. Preservation of XIAP proteins represents a key mechanism by which PGI(2) protects endothelial cells from oxidant-induced apoptosis.
Liou
Jun-Yang
JY
University of Texas Health Science Center at Houston, Houston, TX 77030, USA. jun-yang.liou@uth.tmc.edu
Matijevic-Aleksic
Nena
N
Lee
Sang
S
Wu
Kenneth K
KK
D000256:Adenoviridae / Q000235:genetics; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins; D053148:Caspase 3 / Q000378:metabolism; D002448:Cell Adhesion; D002478:Cells, Cultured; D045304:Cytochromes c / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D011464:Epoprostenol / Q000031:analogs & derivatives / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D005822:Genetic Vectors; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D007546:Isoquinolines / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology; D024101:Mitochondrial Proteins / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D014452:Ubiquitins / Q000378:metabolism*; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism*; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism
D017304:Annexin A5; D051017:Apoptosis Regulatory Proteins; C412403:DIABLO protein, human; D005419:Flavonoids; D047908:Intracellular Signaling Peptides and Proteins; D007546:Isoquinolines; D024101:Mitochondrial Proteins; D016877:Oxidants; D047428:Protein Kinase Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; D013449:Sulfonamides; D014452:Ubiquitins; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; C026678:carboprostacyclin; D045304:Cytochromes c; D006861:Hydrogen Peroxide; D011464:Epoprostenol; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human; D048049:Extracellular Signal-Regulated MAP Kinases; D053148:Caspase 3; D018631:ras Proteins; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one