Expression of two endoplasmic reticulum stress markers, GRP78 and GADD153, in rat retinal detachment model and its implication

Abstract

Purpose 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. Materials and 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 (Po0.05). 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 (Po0.05). 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 (Po0.05). 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.

Proliferative vitreoretinopathy: A new concept of disease pathogenesis and practical consequences

“…Another non-apoptotic pathway for cell death can be triggered by prolonged or excessive stress placed upon the endoplasmic reticulum. This programmed, endoplasmic reticulum stress-mediated pathway is important in neuronal death in neurodegenerative disorders and has been identified in experimental RD (Liu et al, 2010). Additionally, autophagy, a form of cellular recycling, is also upregulated in RD (Chinskey et al, 2014;Cook et al, 1995).…”

Endoplasmic Reticulum Stress-associated Cone Photoreceptor Degeneration in Cyclic Nucleotide-gated Channel Deficiency

“…Indeed caspase-3, the executioner caspase in the classical mitochondrion-mediated pathway, appears to play a different role in varying types of photoreceptor degeneration. Activation of caspase-3 was detected in transgenic rats with rhodopsin mutations (58), and use of a caspase-3 inhibitor reduced the apoptotic cell death in tubby mice (59); however, photoreceptor death in rd1 mice was shown to be caspase-3-independent (60), and lack of caspase-3 activation was also reported in animal models of induced retinal degeneration (light damage and retinal detachment) (19). Thus, though apoptotic cell death has been shown as a common cause of many types of photoreceptor degeneration (17), multiple and distinct pathways are likely engaged (61), and the mechanisms might vary between different pathological disorders.…”

“…We observed increased levels of CHOP and elevations of Grp78/Bip and phospho-eIF2␣ in CNG channel-deficient retinas, implying an ER stress-activated, CHOPmediated cell death. Indeed, CHOP activation has been shown in P23H rhodopsin transgenic rats (51), Lrat Ϫ/Ϫ mice (52), and in rat models of experimental retinal detachment (19).…”

“…Photoreceptor degeneration is represented by two categories: induced degeneration such as that caused by bright light exposure (18) or retinal detachment (19) and inherited degeneration resulting from a variety of genetic disorders. Inherited rod and cone degeneration causes incurable visual diseases such as retinitis pigmentosa and cone dystrophy.…”

Advanced Oxidation Protein Products Induce Hypertrophy and Epithelial-To-Mesenchymal Transition in Human Proximal Tubular Cells through Induction of Endoplasmic Reticulum Stress

“…Conversely, CHOP is associated with the injury mechanism induced by excessive ER stress. These represent 2 distinct mechanisms that are induced during ER stress and are regarded as markers of ER stress [29,30]. In this study, to examine whether AOPPs triggered ER stress, we examined the expression of GRP78 and CHOP by performing RT-PCR and western-blot assays.…”