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Fei Chen, Yao Yu, Yin Shen; A high sensitivity and kinetics of channelrhodopsin PsCatCh2.0 restores vision function in retinitis pigmentosa mouse model. Invest. Ophthalmol. Vis. Sci. 2020;61(7):2733.
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© ARVO (1962-2015); The Authors (2016-present)
Optogenetics is a potential treatment for restoring physiological and behavior visual responses in retinal degeneration diseases. However, the poor photosensitivity and slow kinetics are limitations in visual information processing. In this study, we design a new optogenetic tools channelrhodopsin PsCatCh2.0 and test the safety and effective of PsCatCh2.0 in the retinal degeneration diseases.
We achieved the expression of PsCatCh2.0 in the inner retina using a recombinant adeno-associated viral vector (rAAV) in rd1 mouse. The rd1 mouse is completely blind in one mouth and used as a retinitis pigmentosa mouse model. Whole cell patch-clamp recordings is used to record the photocurrent responses of PsCatCh2.0 in vivo and in vitro. Immunofluorescence staining was performed to explore the expression pattern of PsCatCh2.0 in the retina. Immediate-early genes (IEGs) such as c-Fos and Arc staining are used to detect the neuronal activity in retina and visual cortex. The light/dark box and optomotor system behavior are carried out to estimate the visual function of PsCatCh2.0 treated mouse.
Compared to traditional channelrhodopsin ChR2 (H134R), PsCatCh2.0 exhibited high light sensitivity and fast kinetics in HEK Cells. In our experiment, PsCatCh2.0 showed long-term stable express in rd1 mouse retina, and mainly located in the inner retina, mainly in retinal ganglion cells (RGCs) and amacrine cells, a few in horizontal cells, rarely in bipolar cells. In blue light stimulated Light/dark box, the time in light box and movement distance in PsCatCh2.0 treated group were significant shorter compared to rd1 mouse, while close to the wild type mice. Similarity, PsCatCh2.0-treated rd1 mice also showed better visual tracking behavior with the peak spatial frequency of 0.17±0.04 cycles per degree (cpd) compared to rd1 mice. Furthermore, the expression of c-Fos and Arc both showed significantly up-regulated in retina and visual cortex after light stimulation, which indicated an effective visual signal transmission to the brain.
The expression of PsCatCh2.0 could successfully restored the vision functions of blind mouse, which might be potential therapy tool in retinal degeneration diseases in the future.
This is a 2020 ARVO Annual Meeting abstract.
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