Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

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

ABSTRACT: Oxidative stress has been implicated in the pathogenesis of age-related macular degeneration, the leading cause of blindness in older adults, with retinal pigment epithelium (RPE) cells playing a key role. To better understand the cytotoxic mechanisms underlying oxidative stress, we used a mouse model of iron overload, as iron can catalyze reactive oxygen species formation in the RPE. In a liver-specific Hepc (Hamp) knockout murine model of systemic iron 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 of lysosomes were galectin-3 positive, suggesting cytotoxic lysosomal membrane permeabilization. RNA sequencing was performed and did not show evidence of upregulation of CLEAR network genes, suggesting that the lysosomal accumulation was due to decreased lysosomal turnover and not increased lysosomal biogenesis. Collectively, these results demonstrate that iron overload induces lysosomal accumulation and impairs lysosomal function, likely owing to iron-induced lipid peroxides that can inhibit lysosomal enzymes.

ORGANISM(S): Mus musculus

PROVIDER: GSE237309 | GEO | 2023/07/13

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

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

Iron accumulation and changes of cellular organelles in WDR45 mutant fibroblasts

Project description: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.

2021-11-17 | GSE184520 | GEO

Liver sinusoidal endothelial cells induce BMP6 expression in response to non-transferrin bound iron

Project description:Homeostatic adaptation to systemic iron overload involves transcriptional induction of bone morphogenetic protein 6 (BMP6) in liver sinusoidal endothelial cells (LSECs). BMP6 is then secreted to activate signaling to the iron hormone hepcidin (Hamp) in neighboring hepatocytes. To explore the mechanism for iron sensing by LSECs, we generated TfrcTek-Cre mice with endothelial cell-specific ablation of transferrin receptor 1 (Tfr1). We also used wild type mice to characterize LSEC-specific molecular responses to iron by single cell transcriptomics. TfrcTek-Cre animals tend to have increased liver iron content compared to Tfrcfl/fl controls but do not exhibit blunted Bmp6 or Hamp mRNA expression. They respond to dietary iron challenges with Bmp6 and Hamp induction, yet sometimes to levels slightly lower relative to liver iron load. We noted that liver Bmp6 and Hamp mRNA levels significantly correlated with serum non-transferrin bound iron (NTBI) that emerged following dietary iron loading in both TfrcTek-Cre and Tfrcfl/fl mice. High dietary iron triggered more profound alterations in the LSEC transcriptome of Tfrcfl/fl mice compared to holo-transferrin injection. These culminated in robust induction of Bmp6 and other nuclear factor erythroid 2-related factor 2 (Nrf2) target genes, as well as Myc target genes involved in ribosomal biogenesis and protein synthesis. Taken together, our data suggest that during systemic iron overload, LSECs internalize NTBI, which promotes oxidative stress and thereby transcriptionally induces Bmp6 via Nrf2. The contribution of Tfr1 and transferrin-bound iron to Bmp6 induction is minimal.

2022-12-21 | GSE215324 | GEO

Effect of SPNS1 on lipid metabolism in mice

Project description:Accumulation of sphingolipids, especially sphingosines, in the lysosomes is attributed to the pathogenesis of several lysosomal storage diseases. In searching for a lysosomal protein that mediates the release of sphingosines, we identified SPNS1 which shares the highest homology to SPNS2, a sphingosine-1-phosphate (S1P) transporter. We generated knockout cells and mice for Spns1 and employed lipidomics and metabolomics to identify SPNS1 ligands. We found that knockouts of Spns1 resulted in the accumulation of sphingolipids including sphingosines in embryonic brains and cell lines. These results suggest that deficiency of SPNS1 affects the clearance of sphingolipids in lysosomes. Biochemical assays demonstrated that sphingosines released from lysosomes required SPNS1. Postnatal deletion of Spns1 in mice causes lipid accumulation in the lysosomes and pathological conditions that are reminiscent of sphingolipid lysosomal storage diseases. These results reveal a critical molecular role of SPNS1 as a transporter for lysosphingolipids and lysoglyerophospholipids from the lysosomes and link its physiological roles with lysosomal storage diseases.

2024-06-12 | GSE240323 | GEO

Retinal cells derived from patients with DRAM2-dependent CORD21 dystrophy exhibit key lysosomal enzyme deficiency and lysosomal content accumulation

Project description:Biallelic DRAM2 mutations cause an autosomal recessive cone-rod dystrophy named CORD21 typically manifesting by the third decade of life. DRAM2 localises to the lysosomes of photoreceptor and retinal pigment epithelium (RPE) cells, however, it remains unclear how DRAM2 contributes to retinal degeneration. Herein, we have derived and characterised retinal organoids (ROs) and RPE cells from two CORD21 induced pluripotent stem cells (iPSCs) lines. CORD21 ROs and RPE manifested abnormal lipid metabolism, autophagic flux defects, aberrant lysosomal content accumulations and reduced lysosomal enzyme activity. A combined proteomics and western blot approach revealed the involvement of DRAM2 in vesicular trafficking that was further corroborated by the immunofluorescent co-localisation of DRAM2 with clathrin adaptor-related proteins AP-1 and AP-3 in ROs. Collectively, our data suggest an indispensable role for DRAM2 in the maintenance of photoreceptors and RPE cells by overseeing the transport of lysosomal enzymes.

2024-02-27 | MSV000094178 | MassIVE

A Liver Hepcidin-Intestinal HIF-2α Axis Regulates Iron Absorption During Systemic Iron Deficiency, Hypoxia and Hemochromatosis

Project description:Iron-related disorders are among the most prevalent diseases worldwide. Systemic iron homeostasis requires hepcidin (Hamp), a hepatic-derived hormone that controls iron mobilization through its molecular target, ferroportin (FPN), the only known mammalian iron exporter. Here, we took a transcriptomic approach to to compare the duodenal transcriptome during systemic iron demand to that of hepcidin-deficiency iron overload. Hampfl/fl (control) and AlbCreERT2;Hampfl/fl mice were placed on iron-replete and low-iron diets and were sacrificed two weeks following tamoxifen treatment. Duodenum RNA expression was compared across genotypes and across iron-replete and low iron diets.

2018-12-12 | E-MTAB-7329 | biostudies-arrayexpress

Ferroptosis inhibition by oleic acid mitigates iron-overload-induced injury

Project description:Iron overload, characterized by accumulation of iron in tissues, induces a multiorgan toxicity whose mechanisms are not fully understood. Using cultured cell lines, Caenorhabditis elegans, and mice, we found that ferroptosis occurs in the context of iron-overload-mediated damage. Exogenous oleic acid protected against iron-overload-toxicity in cell culture and Caenorhabditis elegans by suppressing ferroptosis. In mice, oleic acid protected against FAC-induced liver lipid peroxidation and damage. Oleic acid changed the cellular lipid composition, characterized by decreased levels of polyunsaturated fatty acyl phospholipids and decreased levels of ether-linked phospholipids. The protective effect of oleic acid in cells was attenuated by GW6471 (a PPAR- antagonist), as well as in Caenorhabditis elegans lacking the nuclear hormone receptor NHR-49 (a PPAR- functional homologue). These results highlight ferroptosis as a driver of iron-overload-mediated damage, which is inhibited by oleic acid. This monounsaturated fatty acid represents a potential therapeutic approach to mitigating organ damage in iron overload individuals.

2023-10-02 | GSE243891 | GEO

ESCRT-I controls lysosomal membrane protein homeostasis and restricts MCOLN1-dependent TFEB/TFE3 signaling.

Project description:Within the endolysosomal pathway in mammalian cells, ESCRT complexes facilitate degradation of membrane proteins from limiting membranes of late endosomes. Recent studies revealed that yeast ESCRT proteins also sort for degradation, ubiquitinated proteins from vacuolar membrane. However, whether mammalian ESCRTs perform similar function at lysosomes remained unknown. Here, we studied the involvement of mammalian ESCRT-I in maintaining lysosomal membrane homeostasis and its implication in lysosome-related signaling. We show that ESCRT-I restricts the size of lysosomes and promotes degradation of lysosomal Ca2+ channel, MCOLN1 protein. ESCRT-I depletion induced transcriptional response related to MiT-TFE signaling and cholesterol biosynthesis, pointing to lysosomal dysfunction. The lack of ESCRT-I promoted abnormal cholesterol accumulation on lysosomes and activated TFEB/TFE3 transcription factors in Ca2+-MCOLN1-dependent, but lipid-independent manner. Hence, our study provides evidence that ESCRT-I maintains lysosomal homeostasis and elucidates MiT-TFE regulatory mechanism activated in response to ESCRT-I deprivation

2022-03-28 | GSE178665 | GEO

Cell Autonomous Lipid Handling Defects in Stargardt iPS Cell-Derived Retinal Pigment Epithelium Cells

Project description:Stargardt retinopathy is an inherited form of macular degeneration caused by mutations in gene ABCA4 and characterized by the accumulation of lipid-rich deposits in the retinal pigment epithelium (RPE), RPE atrophy, and photoreceptor cell death. Inadequate mechanistic insights into pathophysiological changes occurring in Stargardt RPE have contributed to its lacking treatments. Here we show that ABCA4 knockout or Stargardt patient’s induced pluripotent stem cells-derived RPE (STGD1-iRPE) differentiate normally but display intracellular lipid and ceramide deposits reminiscent of the disease phenotype. STGD1-iRPE also shows defective photoreceptor outer segment (POS) processing and reduced cathepsin B activity, indicating higher lysosomal pH. Lipid deposits in STGD1-iRPE are reduced by increasing the activity of ABCA1, a lipid transporter, and ABCA4 ortholog. Overall, our work suggests that ABCA4 is involved in POS and lipid handling in RPE cells and provides guidance for ongoing gene therapy approaches to target both RPE and photoreceptor cells for an effective treatment.

2022-11-16 | GSE198362 | GEO

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

Project description:Hereditary hemochromatosis and transfusional iron overload are frequent clinical conditions associated with progressive iron accumulation in parenchymal tissues leading to eventual organ failure. We have discovered a novel mechanism to reverse iron overload by pharmacological modulation of the divalent metal transporter-1 (DMT-1). DMT-1 mediates intracellular iron transport during the transferrin cycle and apical iron absorption in the duodenum. Additional functions in iron handling in the kidney and liver are less well understood. We show that the L- type calcium-channel blocker nifedipine increases DMT-1 mediated cellular iron transport 10-to 100-fold at concentrations between 1-100 uM. Mechanistically, nifedipine causes this effect by prolongation of the activity of DMT-1 to transport iron. We show that nifedipine mobilizes iron from the liver of mice with primary and secondary iron overload, and enhances urinary iron excretion. Modulation of DMT-1 function by L-type calcium-channel blockers emerges a novel pharmacological concept to treat iron overload disorders.<br> <br> In this experiment mice were subjected to dietary iron overload before being treated with nifedipine at 5 ug/g bodyweight, or mock treated with the same volume of solvent.

2007-03-01 | E-MEXP-982 | biostudies-arrayexpress

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data