Abstract
Purpose :
Retinitis Pigmentosa (RP), a hereditary disease causing photoreceptors degeneration and blindness, is characterized by high genetic heterogeneity. However, common molecular events like oxidative stress, inflammation and metabolic alterations are known to contribute to the disease progression. In this study we took advantage of an in vitro model of photoreceptor degeneration to highlight affected molecular pathways and identify possible novel therapeutic targets for RP.
Methods :
RNA-Seq analysis was performed in 661W-A11 cells treated with Zaprinast. Altered expression of selected candidate genes was assessed in RNA from two different RP mouse models, rd10 and RHOP23H/+, at the peak of photoreceptor degeneration. Gene expression was evaluated in total retinal extracts or rods enriched extracts (CD73+ fraction). For specific altered genes, protein levels were analyzed by Western Blot in the cellular model and in RHOP23H/+ retinas.
Results :
Downregulation of genes related to lipid biosynthesis pathway was observed in 661W-A11 cells after Zaprinast treatment. Expression of Hk2, encoding the key enzyme for aerobic glycolysis, was significantly lower upon stress. These data hinted an overall disruption of cellular metabolic homeostasis. We confirmed lipid dysregulation by lipid staining in Zaprinast treated cells. In accordance with the in vitro model, lipid and glycolysis related genes were found downregulated also in rd10 retinas at postnatal day 18 (PN18) and in RhoP23H/+ retinas at PN19, time points previously defined as peak of photoreceptor cell death. We confirmed that the gene dysregulation was happening in photoreceptor cells by Real-time qPCR in the CD73+ enriched rods fraction from the RhoP23H/+ murine model.
Conclusions :
Our results suggest an alteration of expression in lipid and aerobic glycolysis related genes during retinal degeneration. These alterations may lead to crucial metabolic dysfunctions that are critical for rod survival. Further elucidations of the contribution of dysregulated metabolic processes to photoreceptor cell death might help the identification of novel biomarkers and mutation-independent neuroprotective strategies.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.