Role of eIF5A in TNF-alpha-mediated apoptosis of lamina cribrosa cells.
Invest Ophthalmol Vis Sci
; 45(10): 3568-76, 2004 Oct.
Article
em En
| MEDLINE
| ID: mdl-15452064
ABSTRACT
PURPOSE:
To determine the role of eukaryotic translation initiation factor 5A (eIF5A) in TNF-alpha-induced apoptosis of lamina cribrosa (LC) cells.METHODS:
LC cells were isolated from optic nerve heads of eyes of two human donors. The cells were treated with TNF-alpha and camptothecin, a TNF synergist, and the incidence of apoptosis was scored by Hoechst staining. Expression of eIF5A protein in response to camptothecin or a combination of camptothecin and TNF-alpha was determined by Western blot analysis. The ability of small inhibitory (si)RNAs directed against eIF5A to protect LC cells from TNF-alpha-induced apoptosis was determined by Hoechst and TUNEL staining of transfected LC cells.RESULTS:
TNF-alpha and camptothecin synergized to induce greater than two times more apoptosis in LC cells than when the cells were treated with TNF-alpha or camptothecin separately. Expression of eIF5A protein increased significantly after 8 hours of exposure to TNF-alpha and camptothecin, but not in response to camptothecin alone. siRNAs directed against eIF5A reduced apoptosis of LC cells in response to TNF-alpha and camptothecin by between 35% and 69%, as determined by Hoechst staining. An siRNA against glyceraldehyde-3-phosphate dehydrogenase (GAPDH) also reduced apoptosis of LC cells by 42%. TUNEL of transfected LC cells treated with TNF-alpha and camptothecin revealed an 80% reduction in apoptosis with siRNA against eIF5A.CONCLUSIONS:
TNF-alpha, in synergy with camptothecin, induces apoptosis in human LC cells. eIF5A is upregulated by LC cells in response to TNF-alpha, and siRNAs against eIF5A protect LC cells from apoptosis. Thus, eIF5A appears to be a novel proapoptotic protein in the TNF pathway and a possible target for treatment of glaucoma.
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Base de dados:
MEDLINE
Assunto principal:
Disco Óptico
/
Fatores de Iniciação de Peptídeos
/
Fator de Necrose Tumoral alfa
/
Proteínas de Ligação a RNA
/
Apoptose
Tipo de estudo:
Clinical_trials
Limite:
Adolescent
/
Aged
/
Aged80
/
Humans
/
Male
Idioma:
En
Revista:
Invest Ophthalmol Vis Sci
Ano de publicação:
2004
Tipo de documento:
Article
País de afiliação:
Canadá