Dataset Information

RNA-seq analysis of ageing human retinal pigment epithelium: Unexpected up-regulation of visual cycle gene transcription.

ABSTRACT: Ageing presents adverse effects on the retina and is the primary risk factor for age-related macular degeneration (AMD). We report the first RNA-seq analysis of age-related transcriptional changes in the human retinal pigment epithelium (RPE), the primary site of AMD pathogenesis. Whole transcriptome sequencing of RPE from human donors ranging in age from 31 to 93 reveals that ageing is associated with increasing transcription of main RPE-associated visual cycle genes (including LRAT, RPE65, RDH5, RDH10, RDH11; pathway enrichment BH-adjusted P = 4.6 × 10^-6 ). This positive correlation is replicated in an independent set of 28 donors and a microarray dataset of 50 donors previously published. LRAT expression is positively regulated by retinoid by-products of the visual cycle (A2E and all-trans-retinal) involving modulation by retinoic acid receptor alpha transcription factor. The results substantiate a novel age-related positive feedback mechanism between accumulation of retinoid by-products in the RPE and the up-regulation of visual cycle genes.

SUBMITTER: Butler JM

PROVIDER: S-EPMC8184696 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Lipofuscin accumulates with age in the retinal pigment epithelium (RPE) in discrete granular organelles and may contribute to age-related macular degeneration. Because previous studies suggest that lipofuscin contains protein that may impact pathogenic mechanisms, we pursued proteomics analysis of lipofuscin. The composition of RPE lipofuscin and its mechanisms of pathogenesis are poorly understood in part because of the heterogeneity of isolated preparations. We purified RPE lipofuscin granules by treatment with proteinase K or SDS and showed by light, confocal, and transmission electron microscopy that the purified granules are free of extragranular material and associated membranes. Crude and purified lipofuscin preparations were quantitatively compared by (i) LC MS/MS proteomics analyses, (ii) immunoanalyses of oxidative protein modifications, (iii) amino acid analysis, (iv) HPLC of bisretinoids, and (v) assaying phototoxicity to RPE cells. From crude lipofuscin preparations 186 proteins were identified, many of which appeared to be modified. In contrast, very little protein ( approximately 2% (w/w) by amino acid analysis) and no identifiable protein were found in the purified granules, which retained full phototoxicity to cultured RPE cells. Our analyses showed that granules in purified and crude lipofuscin preparations exhibit no statistically significant differences in diameter or circularity or in the content of the bisretinoids A2E, isoA2E, and all-trans-retinal dimer-phosphatidylethanolamine. The finding that the purified granules contain minimal protein yet retain phototoxic activity suggests that RPE lipofuscin pathogenesis is largely independent of associated protein. The purified granules also exhibited oxidative protein modifications, including nitrotyrosine generated from reactive nitrogen oxide species and carboxyethylpyrrole and iso[4]levuglandin E(2) adducts generated from reactive lipid fragments. This finding is consistent with previous studies demonstrating RPE lipofuscin to be a potent generator of reactive oxygen species and supports the hypothesis that such species, including reactive fragments from lipids and retinoids, contribute to the mechanisms of RPE lipofuscin pathogenesis.

Dataset Information

RNA-seq analysis of ageing human retinal pigment epithelium: Unexpected up-regulation of visual cycle gene transcription.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets