Expression of two endoplasmic reticulum stress markers, GRP78 and GADD153, in rat retinal detachment model and its implication.
OBJECTIVE
To investigate the expression of endoplasmic reticulum (ER) stress-related genes, glucose-regulated protein 78 (GRP78) and growth arrest DNA damage-inducible gene 153 (GADD153)/CPEBP homologous protein (CHOP), in rat retinal detachment (RD) model.


METHODS
At various time points after RD, the apoptosis of retinal cells was detected by TdT-mediated fluorescein-16-dUTP nick-end labelling (TUNEL) assay; GRP78 and GADD153 mRNA levels were detected by reverse transcription (RT)-PCR; proteins were detected by western blotting analysis; protein distributions in the retinal cells were observed by immunofluorescence using laser-scanning confocal microscope.


RESULTS
After RD, the apoptosis was peaked on 2-4 d and then dropped down. The GRP78 mRNA and GADD153 mRNA levels in RD groups on 0.5, 1, 2, and 4 d were all significantly higher than those in the control group (P<0.05). The expression of GRP78 mRNA peaked on 1-2 d after RD. Expression of GRP78 protein was significantly higher than that in the normal control group on 0.5, 1, 2, 4, 8, 16, and 32 d after RD (P<0.05). The expression of GRP78 protein was observed in all the layers of retina in the RD groups, and peaked on 8, 16, and 32 d. The expression of GADD153 protein, mostly in photoreceptor layers, was significantly higher than that in the control group on 0.5, 1, 2, and 4 d after RD (P<0.05).


CONCLUSIONS
ER stress-related markers, GRP78 and GADD153, are elevated after RD. The elevation of GADD153 is in parallel with the post-RD apoptosis of retinal cells, suggesting that ER stress-mediated death is likely to be activated after RD and involved in post-RD vision loss.
Liu
H
H
Department of Ophthalmology, Affiliated First People's Hospital of Shanghai JiaoTong University, Shanghai, China.
Qian
J
J
Wang
F
F
Sun
X
X
Xu
X
X
Xu
W
W
Zhang
X
X
Zhang
X
X
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D004195:Disease Models, Animal; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012163:Retinal Detachment / Q000378:metabolism* / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013312:Stress, Physiological / Q000502:physiology*; D051742:Transcription Factor CHOP / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP
D015415:Biomarkers; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D051742:Transcription Factor CHOP; C497251:Ddit3 protein, rat; C051684:GRP78 protein, rat; D000091342:Endoplasmic Reticulum Chaperone BiP