Abstract
Purpose :
The purpose of this study was to investigate the role of Lsd1 in retinal development by deleting Lsd1 in all retinal progenitor cells. Lysine specific demethylase 1 (Lsd1) is the only histone demethylase that is able to demethylate mono- and di-methyl groups on H3K4 and H3K9. Previously, we have shown that Lsd1 is ubiquitously expressed throughout the developing retinoblast and in the majority of mature retinal neurons (Ferdous et. al IOVS 2019 PMCID: PMC6827424) . Using a Chx10-Cre driver line, we generated a transgenic mouse line to delete Lsd1 through the entire retinoblast lineage. Chx10 is a transcription factor that is expressed in all retinal progenitor cells (RPCs) starting about embryonic day 14.5 (E14.5) and is critical to progenitor cell proliferation and specifically bipolar cell determination. We hypothesize that deletion of Lsd1 early in retinal development will result in either 1) a failure of RPCs to proliferate or 2) the death of RPCs due to transcriptional abnormalities which could result in a reduction in retinal thickness and subsequently visual function defects.
Methods :
After generating Chx10-Cre Lsd1 lox/lox mice, we tested mice at P30 and P45 for visual function, using electroretinograms (ERGs), and in vivo imaging to obtain SD-OCT and cSLO images. Afterwards, eyes were enucleated and fixed for H&E staining and immunocytochemistry staining.
Results :
We have observed a marked reduction in ERGs a- and b- waves in both scotopic and photopic conditions as well as cone flicker responses at P30 and P45 compared to littermate Cre negative controls. This decrease in visual function is corroborated with reductions in total retinal thickness and ONL thickness as measured from SD-OCT images at both ages. H&E stained sagittal sections indicate the same retinal thinning. Additionally, there is an increase in TUNEL positive cells in the Chx10-Cre Lsd1 loxlox compared to controls.
Conclusions :
Our data supports the notion that Lsd1 is necessary for neuronal development specifically in the retina. Adult Chx10-Cre Lsd1 lox/lox mice show impaired visual function and retinal morphology and future experiments will continue to characterize the timeline of morphological defects during embryonic development as well as investigate epigenome and transcriptome abnormalities leading to these defects.
This is a 2021 ARVO Annual Meeting abstract.