Abstract
Purpose :
Retinal degenerative diseases are characterized by their irreversible photoreceptor loss caused by genetic mutations or environmental factors, which lead to vision loss. We have previously reported that Leukemia Inhibitory Factor (LIF) promotes neuroprotective gene expression through activation of the transcription factor STAT3. We performed an unbiased gene expression study in mouse rods after LIF treatment to identify downstream protective mechanisms.
Methods :
LIF or saline was administered to two-month-old BALB/c mice by intravitreal injections. After two days, retinal tissues were dissected, dissociated, and subjected to single-cell RNA sequencing (scRNA-seq) using 10X genomics Chromium v3 reagents and Cell Ranger pipeline. Using Seurat in R-studio, we bioinformatically isolated rod and cone cells, and identified differentially expressed genes (DEGs) using DESeq2. Significant changes were defined by an adjusted p-value <0.05.
Results :
Over 300 DEGs were found in the LIF-treated rods compared to control rods. Key findings include upregulation of genes involved in cell survival, protein folding, DNA repair, and transcription factors involved cellular stress response (Atf3, Parp14, Gadd45b, Gdd45g, Cryaa, Cryab, and Hspb1). We observed 14 photoreceptor function genes downregulated, as well as regulators of mitochondrial biogenesis, and cell death-related genes.
Conclusions :
LIF-mediated neuroprotection is associated with induced expression of multiple pro-survival genes regulating DNA repair and protein folding, and suppression of normally highly expressed photoreceptor genes. We have previously reported that LIF can slightly reduce photoreceptor function through suppression of phototransduction genes as a protective response. However, these data also suggest that LIF initiates protection by promoting DNA repair, protein folding, and shifting metabolic activity. Some of these changes in gene expression can be directly regulated by Stat3 activation. However, we observed multiple transcription factors with altered expression, so some of the gene regulation is likely indirect and secondary to Stat3 activation. Future experiments will identify direct versus indirect regulated genes, and determine which pathways are critical for LIF-mediated protection.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.