Abstract
Purpose::
Endoplasmic reticulum (ER) stress is involved in the pathogenesis of chronic neurodegenerative disorder, Parkinson’s disease. To determine whether ER stress is also associated with retinal ganglion cell death, we examined the relationship between serum deprivation-induced stress and C/EBP homologues protein (CHOP) in a transformed retinal ganglion cell line, RGC-5.
Methods::
After the culture of RGC-5 in DMEM containing 10% FBS, the medium was replaced to serum-free DMEM. To evaluate the expression levels of mRNA for CHOP and the protein after serum deprivation, real-time RT-PCR and immunocytochemistry were performed.
Results::
The expression level of CHOP mRNA at 12hrs after serum deprivation was 95 ± 28 (mean ± standard error) % of the level before deprivation, showing no significant change. Then, the expression level significantly increased to 330 ± 27% at 24 hrs and 1,320 ± 116% at 36 hrs. Furthermore, the mean number of CHOP-positive cells in RGC-5 was 0 ± 0% until 24 hrs, but gradually increased to 0.85 ± 0.31% and 5.57 ± 1.21% at 36 and 48 hrs, respectively.
Conclusions::
CHOP is induced in RGC-5 by serum deprivation in time-dependent manner, suggesting that ER stress may be involved in retinal ganglion cell death.
Keywords: ganglion cells • stress response • apoptosis/cell death