title: Oxidant-induced cell death in retinal pigment epithelium cells mediated through the release of apoptosis-inducing factor.
abstract: In the present study, the pathways involved in oxidant-induced cell death of a primary cell of the retina, ARPE-19, were investigated and compared with a leukemic cell, U937 cells. Both ARPE-19 and U937 cells exhibited similar viability when exposed to menadione. At lethal doses, both cell lines demonstrated extensive membrane blebbing. However, although U937 cells exhibited caspase-3, -9 PARP cleavage and 200 bp laddering, no such cleavage or laddering was noted in ARPE-19 cells. Furthermore, addition of exogenous cytochrome c and ATP to a cell-free system again resulted in cleavage of caspase-3 and -9 in extracts of U937 but not ARPE cells. Further studies in ARPE-19 cells undergoing menadione-induced cell death demonstrated mitochondrial membrane depolarization, release of cytochrome c, nuclear translocation of apoptosis-inducing factor and subsequent 50 kilo-base pair laddering, and nuclear shrinkage. All of these findings were abrogated by the pretreatment of ARPE-19 cells with hepatocyte growth factor/scatter factor. These findings demonstrate the complex nature of cell death in primary cells of the retina and highlight the role of caspase-independent signals, growth factors and intracellular survival factors in programmed cell death pathways.
authors.affiliation: National Eye Institute, Building 10 - Room 10N119, 9000 Rockville Pike, Bethesda, Maryland 20892-1857, USA.
authors.forename: Congxiao
authors.initials: C
authors.lastname: Zhang
authors.forename: Judit
authors.initials: J
authors.lastname: Baffi
authors.forename: Scott W
authors.initials: SW
authors.lastname: Cousins
authors.forename: Karl G
authors.initials: KG
authors.lastname: Csaky
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D017209:Apoptosis; D051033:Apoptosis Inducing Factor; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D016923:Cell Death; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D002474:Cell-Free System / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D053938:DNA Fragmentation; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D005420:Flavoproteins / Q000378:metabolism*; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism*; D010857:Pigment Epithelium of Eye / Q000166:cytology*; D021381:Protein Transport; D012160:Retina / Q000166:cytology; D013347:Subcellular Fractions / Q000378:metabolism; D020298:U937 Cells
chemical_list: C494829:AIFM1 protein, human; D051033:Apoptosis Inducing Factor; D005420:Flavoproteins; D008565:Membrane Proteins; D016877:Oxidants; D017228:Hepatocyte Growth Factor; D000255:Adenosine Triphosphate; D045304:Cytochromes c; D004247:DNA; D020169:Caspases