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Iron accumulation and changes of cellular organelles in WDR45 mutant fibroblasts

ABSTRACT: Iron overload in the brain, defined as excess stores of iron, is known to be related to neurological disorder. Among neurodegeneration with brain iron accumulation, we reported a specific point mutation, 977-1G>A in WDR45, showing iron accumulation in the brain, and autophagy defects in the fibroblasts. In this study, we investigated whether fibroblasts with mutated WDR45 accumulated iron, and other effects on cellular organelles. We first identified the main location of iron accumulation in the mutant fibroblasts and then investigated the effects of this accumulation on other organelles, including lipid droplets, mitochondria, and lysosomes. Ultrastructure analysis using transmission electron microscopy (TEM) and confocal microscopy showed structural changes in the organelles. Increased numbers of lipid droplets, fragmented mitochondria, and increased lysosomal vesicles with functional disorder due to WDR45 deficiency were observed. The majority of iron accumulation occurred in the lysosomal vesicles, according to correlative light and electron microscopy (CLEM). These changes were related to defects in autophagy and defective protein and organelle turnover. Gene expression profiling analysis also showed significant changes in lipid metabolism, mitochondrial function, and autophagy-related genes. Those data suggested that functional and structural changes caused impaired lipid metabolism, mitochondrial disorder, and unbalanced autophagy fluxes, due to iron overload.

ORGANISM(S): Homo sapiens

PROVIDER: GSE184520 | GEO | 2021/11/17

REPOSITORIES: GEO

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Iron accumulation and changes of cellular organelles in WDR45 mutant fibroblasts

Project description:Iron accumulation and changes of cellular organelles in WDR45 mutant fibroblasts

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2023-03-31 | PXD039881 | Pride

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Oxidative stress induces lysosomal membrane permeabilization and ceramide accumulation in retinal pigment epithelial cells

Project description:Oxidative stress has been implicated in the pathogenesis of age-related macular degeneration(AMD), the leading cause of blindness in the elderly, with retinal pigment epithelial (RPE) cells playing a key role. To better understand the cytotoxic mechanisms underlying oxidative stress, we used cell culture and mouse models of iron overload, as iron can catalyze reactive oxygen species formation in the RPE. Iron-loading of cultured iPS-RPE cells increased lysosomal abundance, impaired proteolysis, and reduced the activity of a subset of lysosomal enzymes,including lysosomal acid lipase and acid sphingomyelinase. In a murine model of systemiciron overload, RPE cells accumulated lipid peroxidation adducts and lysosomes, developed progressive hypertrophy, and underwent cell death. Proteomic and lipidomic analyses revealed accumulation of lysosomal proteins, ceramide biosynthetic enzymes, and ceramides. The proteolytic enzyme cathepsin D had impaired maturation. A large proportion oflysosomes were galectin-3 positive, suggesting cytotoxic lysosomal membrane permeabilization (LMP). Collectively, these results demonstrate that iron overload induces lysosomal accumulation and impairs lysosomal function, likely due to iron-induced lipid peroxides that can inhibit lysosomal enzymes.

2023-07-19 | PXD043613 | Pride

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2007-11-30 | GSE9726 | GEO

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2019-11-14 | PXD008950 | Pride

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Transcription profiling of liver from wild type and Hfe-/- mice with hereditary hemochromatosis subjected to dietary iron overload and treatment with nifedipine to reverse iron overload

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