Dataset Information

High density lipoproteins – a therapeutic target for age-related macular degeneration

ABSTRACT: We analyzed Apolipoprotein A-1 (ApoA-1) containing lipoproteins isolated from Bruch’s membrane (BrM) of elderly human donor eyes and found a unique proteome, quite different from HDL isolated from donor plasma of the same individuals. The most striking difference is higher concentrations of ApoB and ApoE, which bind to glycosaminoglycans (GAGs). We hypothesize that this interaction promotes lipoprotein deposition onto BrM GAGs, initiating downstream effects that contribute to RPE dysfunction/death. We tested this hypothesis using two therapeutic strategies to alter the lipoprotein/protein profile of these extracellular deposits. First, we used short, heparan sulfate oligosaccharides to remove lipoproteins already deposited in both the extracellular matrix of RPE cells and in aged, donor BrM tissue. Second, we used an ApoA-1 mimetic, 5A peptide, which modulates the relative amounts of cholesterol and ApoA-1, ApoB, and ApoE secreted both apically and basolaterally from primary porcine RPE cells. Significantly, the 5A peptide altered the proteomic profile of circulating HDL and ameliorated some of the potentially harmful changes in protein composition seen with a high fat, high cholesterol diet in a mouse model of AMD. Together, these results indicate that HDL interactions with BrM represent a viable target to slow AMD progression in humans

INSTRUMENT(S): Synapt MS

ORGANISM(S): Homo Sapiens (human) Mus Musculus (mouse)

TISSUE(S): Choroidal Cell Of The Eye, Blood Cell, Blood Plasma, Choroid

DISEASE(S): Degeneration Of Macula And Posterior Pole

SUBMITTER: Nikolai Skiba

LAB HEAD: Catherine Bowes Richman

PROVIDER: PXD020251 | Pride | 2020-08-05

REPOSITORIES: Pride

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High-density lipoproteins are a potential therapeutic target for age-related macular degeneration.

Kelly Una L UL Grigsby Daniel D Cady Martha A MA Landowski Michael M Skiba Nikolai P NP Liu Jian J Remaley Alan T AT Klingeborn Mikael M Bowes Rickman Catherine C

The Journal of biological chemistry 20200731 39

Strong evidence suggests that dysregulated lipid metabolism involving dysfunction of the retinal pigmented epithelium (RPE) underlies the pathogenesis of age-related macular degeneration (AMD), the leading cause of irreversible blindness in the elderly. A hallmark of AMD is the overproduction of lipid- and protein-rich extracellular deposits that accumulate in the extracellular matrix (Bruch's membrane (BrM)) adjacent to the RPE. We analyzed apolipoprotein A-1 (ApoA-1)-containing lipoproteins is ...[more]

PMID: 32737203

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Project description:Purpose: Age-related degeneration (AMD) is a major cause of blindness in developed countries. The molecular pathogenesis of early events in AMD is poorly understood. We investigated differential gene expression in samples of human retinal pigment epithelium (RPE)/choroid from early AMD and control maculas using exon-based arrays. Methods: Gene expression levels in nine early AMD and nine control human donor eyes were assessed using Affymetrix Human Exon ST 1.0 arrays. Two controls did not pass quality control and were removed. Differentially expressed genes were annotated using DAVID, and gene set enrichment analysis (GSEA) was performed on RPE-specific and endothelium-associated gene sets. CFH genotype was also assessed and differential expression was analyzed with respect to high AMD risk (YH/HH) and low AMD risk (YY) genotypes. Results: Seventy-five genes were identified as differentially expressed (raw p-value < 0.01; >50% fold change, mean log2 expression level in AMD or control M-bM-^IM-% median of all average gene expression values); however, no genes were significant (adj. p-value < 0.01) after correction for multiple hypothesis testing. Of 52 genes with decreased expression in AMD (fold change < 0.5; raw p-value < 0.01), 18 genes were identified by DAVID analysis as associated with vision or neurological processes. GSEA of RPE-associated and endothelium-associated genes revealed a significant decrease in genes typically expressed by endothelial cells in the early AMD group compared to controls, consistent with previous histologic and proteomic studies. Analysis with respect to CFH genotype indicated decreased expression of ADAMTS9 in eyes with high-risk genotypes (fold change = -2.61; raw p-value = 0.0008). Conclusions: GSEA results suggest that RPE transcripts are preserved or elevated in early AMD, concomitant with loss of endothelial cell marker expression. These results are consistent with the notion that choroidal endothelial cell dropout occurs early in the pathogenesis of AMD. Using AltAnalyze (ver. 2.0.7 beta), we analyzed nine early AMD and nine control eyes using Affymetrix Human Exon ST 1.0 arrays. Following initial processing in AltAnalyze, two control arrays were identified as potential outliers by tests implement in arrayQualityMetrics, a package for R.

Project description:Purpose: Age-related degeneration (AMD) is a major cause of blindness in developed countries. The molecular pathogenesis of early events in AMD is poorly understood. We investigated differential gene expression in samples of human retinal pigment epithelium (RPE)/choroid from early AMD and control maculas using exon-based arrays. Methods: Gene expression levels in nine early AMD and nine control human donor eyes were assessed using Affymetrix Human Exon ST 1.0 arrays. Two controls did not pass quality control and were removed. Differentially expressed genes were annotated using DAVID, and gene set enrichment analysis (GSEA) was performed on RPE-specific and endothelium-associated gene sets. CFH genotype was also assessed and differential expression was analyzed with respect to high AMD risk (YH/HH) and low AMD risk (YY) genotypes. Results: Seventy-five genes were identified as differentially expressed (raw p-value < 0.01; >50% fold change, mean log2 expression level in AMD or control ≥ median of all average gene expression values); however, no genes were significant (adj. p-value < 0.01) after correction for multiple hypothesis testing. Of 52 genes with decreased expression in AMD (fold change < 0.5; raw p-value < 0.01), 18 genes were identified by DAVID analysis as associated with vision or neurological processes. GSEA of RPE-associated and endothelium-associated genes revealed a significant decrease in genes typically expressed by endothelial cells in the early AMD group compared to controls, consistent with previous histologic and proteomic studies. Analysis with respect to CFH genotype indicated decreased expression of ADAMTS9 in eyes with high-risk genotypes (fold change = -2.61; raw p-value = 0.0008). Conclusions: GSEA results suggest that RPE transcripts are preserved or elevated in early AMD, concomitant with loss of endothelial cell marker expression. These results are consistent with the notion that choroidal endothelial cell dropout occurs early in the pathogenesis of AMD.

Dataset Information

High density lipoproteins – a therapeutic target for age-related macular degeneration

Publications

High-density lipoproteins are a potential therapeutic target for age-related macular degeneration.

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