Lipidomics reveal the protective effects of a vegetable-derived isothiocyanate against retinal degeneration

Abstract

Background: Age-related macular degeneration (AMD) is a leading cause of blindness in the ageing population. Without effective treatment strategies that can prevent disease progression, there is an urgent need for novel therapeutic interventions to reduce the burden of vision loss and improve patients’ quality of life. Dysfunctional innate immune responses to oxidative stress observed in AMD can be caused by the formation of oxidised lipids, whilst polyunsaturated fatty acids have shown to increase the risk of AMD and disease progression in affected individuals. Previously, our laboratory has shown that the vegetable-derived isothiocyanate, L-sulforaphane (LSF), can protect human adult pigment epithelial cells from oxidative damage by upregulating gene expression of the oxidative stress enzyme Glutathione-S-Transferase µ1. This study aims to validate the protective effects of LSF on human retinal cells under oxidative stress conditions and to reveal the key players in fatty acid and lipid metabolism that may facilitate this protection. Methods: The in vitro oxidative stress model of AMD was based on the exposure of an adult retinal pigment epithelium-19 cell line to 200µM hydrogen peroxide. Percentage cell proliferation following LSF treatment was measured using tetrazolium salt-based assays. Untargeted fatty acid profiling was performed by gas chromatography-mass spectrometry. Untargeted lipid profiling was performed by liquid chromatography-mass spectrometry. Results: Under hydrogen peroxide-induced oxidative stress conditions, LSF treatment induced dose-dependent cell proliferation. The key fatty acids that were increased by LSF treatment of the retinal cells include oleic acid and eicosatrienoic acid. LSF treatment also increased levels of the lipid classes phosphatidylcholine, cholesteryl ester and oxo-phytodienoic acid but decreased levels of phosphatidylethanolamine lipids. Conclusions: We propose that retinal cells at risk of oxidative damage and apoptosis can be pre-conditioned with LSF to regulate levels of selected fatty acids and lipids known to be implicated in the pathogenesis and progression of AMD.

Lipidomics reveal the protective effects of a vegetable-derived isothiocyanate against retinal degeneration

“…The drug vehicle control (0.025% DMSO) did not affect the percentage of proliferation regardless of exposure to oxidative stress stimulus, H 2 O 2 ( Figure 2 ; all p values > 0.05) 28 . In the absence of H 2 O 2 , 3 µM - 30 µM LSF treatments did not have a significant impact on cell proliferation ( Figure 2A ; all p values > 0.05).…”

“…In the absence of oxidative stress, no changes in lipid levels between LSF-treated cells and the untreated control were reported (all p values > 0.05; see Underlying data ) 28 . In the presence of oxidative stress, treatment with 5μM LSF did not result in any statistically significant changes in lipid levels (all p values > 0.05; Figure 5A ).…”

“…It is noteworthy that the levels of fatty acids in the untreated control fell below the level of detection and thus the missing values for the control were imputed, a common practice in metabolomics data analysis. In the presence of oxidative stress, there were no consistent differences in the fatty acid levels between the replicate samples within the 5μM LSF or 20μM LSF treatment groups and those within the untreated control group (see Underlying data ) 28 .…”

“…Harvard Dataverse: Lipidomics reveal the protective effects of a vegetable-derived isothiocyanate against retinal degeneration. https://doi.org/10.7910/DVN/C9VCBX 28 …”