Transcriptome Analysis of Long-Term Exposure to Blue Light in Retinal Pigment Epithelial Cells

Abstract

Dry age-related macular degeneration (AMD) is a type of progressive blindness that is primarily due to dysfunction and the loss of retinal pigment epithelium (RPE). The accumulation of N-retinylidene-N-retinylethanolamine (A2E), a by-product of the visual cycle, causes RPE and photoreceptor degeneration that impairs vision. Genes associated with dry AMD have been identified using a blue light model of A2E accumulation in the retinal pigment epithelium and transcriptomic studies of retinal tissue from patients with AMD. However, dry macular degeneration progresses slowly, and current approaches cannot reveal changes in gene transcription according to stages of AMD progression. Thus, they are limited in terms of identifying genes responsible for pathogenesis. Here, we created a model of long-term exposure to identify temporally-dependent changes in gene expression induced in human retinal pigment epithelial cells (ARPE-19) exposed to blue light and a non-cytotoxic dose of A2E for 120 days. We identified stage-specific genes at 40, 100, and 120 days, respectively. The expression of genes corresponding to epithelial-mesenchymal transition (EMT) during the early stage, glycolysis and angiogenesis during the middle stage, and apoptosis and inflammation pathways during the late stage was significantly altered by A2E and blue light. Changes in the expression of genes at the late stages of the EMT were similar to those found in human eyes with late-stage AMD. Our results provide further insight into the pathogenesis of dry AMD induced by blue light and a novel model in vitro with which relevant genes can be identified in the future.

N-retinylidene-N-retinylethanolamine degradation in human retinal pigment epithelial cells via memantine- and ifenprodil-mediated autophagy

“…Further, autophagy activation via the mammalian target of rapamycin (mTOR) or non-mTOR pathway in the retina plays a beneficial role in protecting the retina by maintaining homeostasis via the disassembly and reuse of damaged cells. In the case of dysfunctional autophagy in retinal cells, the function of RPE cell phagocytosis is inhibited, waste products are accumulated owing to the blockage of metabolites that are being removed, and inflammatory pathways, such as the NF-κB pathway, are activated [ 35 , 37 ]. The RPE cells function as the BRB, a specialized barrier in the retina that regulates the movement of substances between the blood and nerve tissues.…”

Epitranscriptome Analysis of Oxidative Stressed Retinal Epithelial Cells Depicted a Possible RNA Editing Landscape of Retinal Degeneration

“…Control cell groups were incubated without A2E. Confluent cultures were transferred to PBS supplemented with Mg 2+ , Ca 2+ and glucose, before exposure to blue light emitted by a tungsten-halogen source (470 ± 20 nm; 0.4 mW/mm 2 ) for 30 min to induce phototoxicity of A2E and subsequent incubation at 37 °C, as already described by confirmed protocols [ 32 , 33 , 34 ]. A2E quantity in cell cultures post blue light induction was then confirmed by HPLC.…”

Endogenous and Exogenous Regulation of Redox Homeostasis in Retinal Pigment Epithelium Cells: An Updated Antioxidant Perspective

“…Transcriptional profiling showed an increased level of markers of apoptosis, autophagy, ER stress, and mitochondrial dysfunction in OS-dependent metabolic disorders in the RPE [ 199 , 200 , 201 , 202 ]. Ex vivo RPE cells from patients with AMD accumulated lipid droplets and glycogen particles, showed increased sensitivity to OS, contained destroyed mitochondria, showed reduced mitochondrial activity, and impaired autophagy, as determined by LC3-II/LC3-I markers [ 203 ].…”