[Activation of endoplasmic reticulum stress proteins in light-induced retinal degeneration].
OBJECTIVE
To investigate the expression of endoplasmic reticulum stress proteins in photoreceptor apoptosis in light-induced retinal degeneration.


METHODS
Exposure to excessive levels of light induced photoreceptor apoptosis and had been previously used as a model for the study of retinal degeneration. Photoreceptor apoptosis was detected by terminal dUTP transferase nick end labeling (TUNEL). The protein expression levels of ER stress sensors including glucosejregulated protein-78 (GRP78/BiP), caspase-12, phospho-eukaryotic initiation factor 2alpha (eIF2alpha) and phospho- double-stranded RNA-activated protein kinase-like endoplasmic reticulum kinase (PERK) were examined by immunojfluorescence and Western blot analysis.


RESULTS
Following light exposure, the protein expression levels of GRP78/BiP, caspase-12, phospho-eIF2alpha and phospho-PERK were up-regulated in a time dependent manner. The up-regulation of these proteins coincided with or preceded the photoreceptor apoptosis. At the peak of their expression, they were mainly located in the photoreceptor inner segments and/or outer nuclear layers (ONL).


CONCLUSIONS
Activation of endoplasmic reticulum stress proteins appears to play an important role in light-induced retinal degeneration. Therefore endoplasmic reticulum stress modulators could become a strong candidate for a therapeutic agent in treatment of these diseases.
Wu
Le-meng
LM
Department of Ophthalmology,Peking University Third Hospital, Peking University Eye Center, Beijing, China.
Guo
Xiu-juan
XJ
Tso
Mark
M
Yang
Li-ping
LP
D000818:Animals; D017209:Apoptosis; D053454:Caspase 12 / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000473:pathology; D000091342:Endoplasmic Reticulum Chaperone BiP; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D006168:Guinea Pigs; D006360:Heat-Shock Proteins / Q000378:metabolism*; D008027:Light / Q000009:adverse effects*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D020419:Photoreceptor Cells, Vertebrate / Q000378:metabolism* / Q000473:pathology; D011817:Rabbits; D011897:Random Allocation; D012160:Retina / Q000378:metabolism / Q000473:pathology; D012162:Retinal Degeneration / Q000209:etiology / Q000378:metabolism*; D019892:eIF-2 Kinase / Q000378:metabolism
D053454:Caspase 12; D000091342:Endoplasmic Reticulum Chaperone BiP; D015852:Eukaryotic Initiation Factor-2; D006360:Heat-Shock Proteins; D019892:eIF-2 Kinase; C000717248:Hspa5 protein, mouse