Abstract
Purpose :
Optic nerve (ON) injury and neurodegenerative disorders trigger a cascade of retinal ganglion cells loss, which leads to the failure of the ON to regenerate. Our current study was to explore the involvement of the alterations of proteome and key candidate proteins in the pathological event of ON degeneration in response to optic nerve crush (ONC).
Methods :
In our current study, we established rat ON injury model through ONC. A quantitative comparison of the proteome in the rat retina was analyzed through TMT labeling, HPLC fractionation, LC-MS/MS and PRM proteomics analysis. Western blot was performed to validate the protein level of the candidate proteins following ON-crushed injury.
Results :
ONC induced a total of 58 proteins downregulated and 13 proteins upregulated in the retina. Subcellular prediction was performed to characterize the subcellular localization of these differentially expressed proteins. ONC downregulated proteins that were mainly accumulated in the nucleus, extracellular domain, cytoplasm, and mitochondria. Most of the upregulated proteins were localized in the nucleus, cytoplasm, endosplasmic reticulum, mitochondria, extracellular region in response to ONC. For the biological process enrichment, the dysregulated proteins are important for maintenance of biological process including cellular metabolic process, phagocytosis, neurological system development, sensory perception, and visual perception. ONC elicited quantitative changes in proteins that associated with extracellular matrix, intermediate filament and cytoskeleton. The identified proteins predominantly participate in structural molecule activity, binding, transport, catalytic activity, and regulating molecular function. We found that longevity regulating pathway was significantly enriched through KEEG enrichment. Notably, of these differentially expressed proteins in the pathway, we noticed that AKT3, one of the isoform of AKT, was the most dysregulated after ONC. We further validated AKT3 protein level and our results showed a markedly decrease in its expression level responding to the ON injury.
Conclusions :
Our proteomic analysis suggests that ON injury imposes a pathological impact on retina through altering proteomic profile. The identification of down-regulation of ATK3 provides a valuable clue that ATK3 is involved in the pathological cascade of ON degeneration and may be an important therapeutic target for ON regeneration.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.