title: Cytosolic phospholipase A2-{alpha} is an early apoptotic activator in PEDF-induced endothelial cell apoptosis.
abstract: Pigment epithelium-derived factor (PEDF) is an intrinsic antiangiogenic factor and a potential therapeutic agent. Previously, we discovered the mechanism of PEDF-induced apoptosis of human umbilical vein endothelial cells (HUVECs) as sequential induction/activation of p38 mitogen-activated protein kinase (MAPK), peroxisome proliferator-activated receptor gamma (PPAR-gamma), and p53. In the present study, we investigated the signaling role of cytosolic calcium-dependent phospholipase A(2)-alpha (cPLA(2)-alpha) to bridge p38 MAPK and PPAR-gamma activation. PEDF induced cPLA(2)-alpha activation in HUVECs and in endothelial cells in chemical burn-induced vessels on mouse cornea. The cPLA(2)-alpha activation is evident from the phosphorylation and nuclear translocation of cPLA(2)-alpha as well as arachidonic acid release and the cleavage of PED6, a synthetic PLA(2) substrate. Such activation can be abolished by p38 MAPK inhibitor. The PEDF-induced PPAR-gamma activation, p53 expression, caspase-3 activity, and apoptosis can be abolished by both cPLA(2) inhibitor and small interfering RNA targeting cPLA(2)-alpha. Our observation not only establishes the signaling role of cPLA(2)-alpha but also for the first time demonstrates the sequential activation of p38 MAPK, cPLA(2)-alpha, PPAR-gamma, and p53 as the mechanism of PEDF-induced endothelial cell apoptosis.
authors.affiliation: Dept. of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Tsung-Chuan
authors.initials: TC
authors.lastname: Ho
authors.forename: Show-Li
authors.initials: SL
authors.lastname: Chen
authors.forename: Yuh-Cheng
authors.initials: YC
authors.lastname: Yang
authors.forename: Tzu-Hsiu
authors.initials: TH
authors.lastname: Lo
authors.forename: Jui-Wen
authors.initials: JW
authors.lastname: Hsieh
authors.forename: Huey-Chuan
authors.initials: HC
authors.lastname: Cheng
authors.forename: Yeou-Ping
authors.initials: YP
authors.lastname: Tsao
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D016718:Arachidonic Acid / Q000378:metabolism; D002057:Burns, Chemical / Q000201:enzymology / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D016510:Corneal Neovascularization / Q000201:enzymology / Q000473:pathology; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology*; D005126:Eye Burns / Q000139:chemically induced / Q000201:enzymology / Q000473:pathology; D005136:Eye Proteins / Q000008:administration & dosage / Q000378:metabolism*; D054513:Group IV Phospholipases A2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D009414:Nerve Growth Factors / Q000008:administration & dosage / Q000378:metabolism*; D047495:PPAR gamma / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D011994:Recombinant Proteins / Q000378:metabolism; D012694:Serine; D015843:Serpins / Q000008:administration & dosage / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D000099174:Pigment Epithelium-Derived Factor
chemical_list: D016718:Arachidonic Acid; D053148:Caspase 3; D005136:Eye Proteins; D054513:Group IV Phospholipases A2; D009414:Nerve Growth Factors; D047495:PPAR gamma; D010726:Phosphodiesterase Inhibitors; D047428:Protein Kinase Inhibitors; D011994:Recombinant Proteins; D012694:Serine; D015843:Serpins; D016159:Tumor Suppressor Protein p53; D048051:p38 Mitogen-Activated Protein Kinases; D000099174:Pigment Epithelium-Derived Factor; C516390:Pla2g4a protein, mouse; C495901:TP53 protein, human; C516389:PLA2G4A protein, human; C505407:CASP3 protein, human