Abstract
Purpose :
X-linked juvenile retinoschisis (XLRS) is an early onset inherited condition characterized by abnormal retinoschisin (RS1) expression. Despite macular dysfunction occurring early in life, it is mostly studied in young adults. Here, we investigate physiological changes along key stages of retinal development in a mouse model of XLRS.
Methods :
We studied the spontaneous and light-driven intracellular calcium dynamics in male RS1 sufficient and RS1 deficient mice expressing GCaMP6f (under the NG2 promoter) in all neuronal, glial, and vascular cells. Optophysiological assessment was carried out in live wholemount retinal explants of cohorts aged P10-11, P14-15, P20-22 and P60-65 for both RS1-/Y; NG2 GCaMP6f-/+ and RS1+/+; NG2 GCaMP6f-/+. We monitored changes in the fluorescence of retinal cells at five simultaneous depths (20 µm intervals) using a Thorlabs Tiberius multi-photon microscope with galvo-resonnant scanning capabilities, at various magnifications (16x, 32x and 64x); spatial (1024, 512 and 256 pixels2) and temporal resolutions (1.53, 3.06 and 15 frames/s).
Results :
Distinct physiological phenotypes in both neural cells and glia were prevalent in the spontaneous activity of RS1-/Y; NG2 GCaMP6f-/+ retinas. At P15, the neural phenotype was defined by the persistence of short bursts of activity in the inner plexiform layer (IPL) with irregular and patchy spiral-shaped trajectories. These ‘wavelets’, not typically observed in wildtype age-matched controls were 1.65s ±0.15 SEM long and spanned across relatively small 137 µm ±30.5 SEM regions. The glial phenotype was defined by a gradual increase in the frequency and radial propagation of spontaneous glial events, gaining statistical significance over the wild type control at P20 (0.72 events/min ±0.11 SEM spreading over an average distance of 64.8 µm ±8.6 SEM).
Conclusions :
The aberrant activity observed in the neurons and glia of developing RS1 deficient retinas may potentially affect further retinal development as well as central targets, leading to deficits in the visual system’s ability to respond adequately to light stimuli.
This is a 2020 ARVO Annual Meeting abstract.