[Endoplasmic reticulum stress proteins are activated in rd retinal degeneration].
OBJECTIVE
To investigate the expression of endoplasmic reticulum (ER) stress proteins in photoreceptor apoptosis in rd mouse (Pde6bRd1/Rd1).


METHODS
Photoreceptor apoptosis in rd mouse was detected by terminal dUTP transferase nick end labeling (TUNEL). The protein expression of ER stress sensors including glucose-regulated protein-78 (GRP78/BiP), caspase-12, phospho-eukaryotic initiation factor 2alpha (eIF2alpha) and phospho-pancreatic ER kinase (PERK) was examined by immunofluorescence and Western Blot analysis.


RESULTS
Accompanying photoreceptor apoptosis in rd mouse, protein expression of GRP78/BiP, caspase-12, phospho-eIF2alpha and phospho-PERK was 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 segment and/or outer nuclear layer (ONL).


CONCLUSIONS
Activation of ER stress proteins appears to play an important role in rd retinal degeneration. Therefore endoplasmic reticulum stress modulators could be a strong candidate as a therapeutic agent in the treatment of these diseases.
Wu
Le-Meng
LM
Peking University Third Hospital, Peking University Eye Center, Beijing 100083, China.
Tso
Mark
M
Zhu
Xiu-An
XA
Guo
Xiu-Juan
XJ
Yang
Li-Ping
LP
D000818:Animals; D017209:Apoptosis; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D012162:Retinal Degeneration / Q000235:genetics / Q000378:metabolism*
D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; C000717248:Hspa5 protein, mouse