Abstract
Purpose :
Glaucoma is characterized by retinal ganglion cell damage, leading to visual field defects and even blindness. Currently, the only established treatment for glaucoma is reduction in intraocular pressure, but new neuroprotective treatment methods are being developed. We have previously shown that Kyoto University Substances (KUSs), which are valosin-containing protein (VCP) modulators, suppress cell death in animal models of glaucoma, retinitis pigmentosa, retinal ischemia, and age-related macular degeneration. The purpose of this study was to elucidate the precise neuroprotective mechanisms of KUSs by focusing on gene expression in mouse with acute retinal ganglion cell damage.
Methods :
We administered KUSs orally for 7 days to Thy1-CFP mice, which express cyan fluorescent protein (CFP) in the retinal ganglion cells. Acute retinal ganglion cell damage was induced by an intravitreal injection of N-methyl-D-aspartic acid (NMDA). Four hours after NMDA injection, CFP-expressing retinal ganglion cells were isolated using a fluorescence-activated cell sorter. RNA was purified from the collected retinal ganglion cells and analyzed using next-generation RNA-sequencing to evaluate gene expression profiles. We focused on two genes, endothelin-1 (Edn1) and endothelin receptor type B (Ednrb), whose expression was upregulated by NMDA injection and downregulated by KUS treatments. The mRNA expression levels of the genes in the neural retina were examined by real-time PCR, and protein levels in the neural retina were confirmed by western blotting and immunostaining.
Results :
The mRNA expression of both Ednrb and Edn1 was higher in the NMDA-injected group than in the control group (p < 0.0001 and p = 0.005, respectively). In contrast, mRNA expression of Ednrb in the NMDA-injected-KUS121-treated group and the NMDA-injected-KUS187-treated group did not significantly differ from that of the control group (p > 0.05). Expression of EDN1 was significantly higher in the NMDA-injected group than in the control group (p = 0.007) as observed in western blot analysis. Immunohistochemical staining showed that EDNRB and EDN1 proteins were strongly expressed in the retinal ganglion cell layer in the NMDA-injected group than in the control group.
Conclusions :
These results suggested that KUSs protect retinal ganglion cells by suppressing the upregulated Edn1 and Ednrb expression.
This is a 2021 ARVO Annual Meeting abstract.