Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Iron loading induces cholesterol synthesis and sensitizes endothelial cells to TNFα-mediated apoptosis

ABSTRACT: In plasma, iron is normally bound to transferrin, but in conditions of iron overload when the iron-binding capacity of transferrin is exceeded, non-transferrin-bound iron (NTBI) appears in plasma. NTBI is taken up by hepatocytes and other parenchymal cells via NTBI transporters and can cause cellular damage by promoting the generation of reactive oxygen species. However, how NTBI affects endothelial cells, the most proximal cell type exposed to circulating NTBI, has not been explored. We modeled in vitro the effects of systemic iron overload on endothelial cells by treating primary human umbilical vein endothelial cells (HUVECs) with NTBI (ferric ammonium citrate, FAC). Using an unbiased approach, we showed by RNA-Seq that iron loading alters lipid homeostasis in HUVECs by inducing SREBP2-mediated cholesterol biosynthesis. We also determined that FAC increased the susceptibility of HUVECs to apoptosis induced by TNFα. Moreover, we showed that cholesterol biosynthesis contributes to iron-potentiated apoptosis. Treating HUVECs with a cholesterol chelator hydroxypropyl-β-cyclodextrin demonstrated that depletion of cholesterol was sufficient to rescue HUVECs from TNFa-induced apoptosis, even in the presence of FAC. Finally, we showed that FAC or cholesterol treatment modulated the TNFα pathway by inducing novel proteolytic processing of TNFR1 to a short isoform that localizes to lipid rafts. Our study raises the possibility that iron-mediated toxicity in human iron overload disorders is at least in part dependent on alterations in cholesterol metabolism in endothelial cells, increasing their susceptibility to apoptosis.

ORGANISM(S): Homo sapiens

PROVIDER: GSE168534 | GEO | 2021/09/01

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

Iron loading induces cholesterol synthesis and sensitizes endothelial cells to TNFα-mediated apoptosis

Project description:Iron loading induces cholesterol synthesis and sensitizes endothelial cells to TNFα-mediated apoptosis

| PRJNA708225 | ENA

Intracellular labile iron is a key regulator of hepcidin expression and iron metabolism

Project description:Liver iron overload can induce hepatic expression of hepcidin and regulates iron metabolism. However, the mechanism of iron regulating iron metabolism remains known. Intracellular labile iron represents the nonferritin-bound, redox-active iron which is transitory and serves as a crossroad of cell iron metabolism. The role of intracellular labile iron played in iron metabolism has largely been elucidated. Here we show that intracellular labile iron of hepatocytes has dual function in iron metabolism. It can induce hepatocytes expressing hepcidin via ER stress induced transcription factors on the one hand, on the other hand stimulate BMP2 and BMP6 expression of liver sinusoidal endothelial cells (LSECs) though TNFα secreted by hepatocytes to further regulate iron metabolism. Blockade of TNFα could dysregulate the iron metabolism during iron overload. Our findings reveal the important role of intracellular labile iron in iron metabolism and represent a novel way to modulate iron metabolism during iron overload.

2023-05-03 | GSE186655 | 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

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

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

Effects of iron overload on gene expression in the cardiac and skeletal muscle of mice

Project description:Hereditary Hemochromatosis (HH) is an autosomal recessive disorder characterized by an abnormally low expression or functional derangement of the iron regulatory hormone hepcidin. The absorption of dietary iron is disproportionate in these patients, leading to iron deposition in several tissues and consequent damage of organs including liver, heart, and pancreas. Late complications in absence of diagnosis and treatment include cirrhosis, hepatocellular carcinoma, cardiomyopathy and diabetes. Unfortunately, iron overload appears also as an acquired complication. This is the case of a variety of anemias (thalassemias, myelodysplastic syndromes, hemoglobinopathies, etc.) in which compensating mechanisms increase iron absorption. Another cause of iron overload in these patients are the repeated transfusional treatments they receive. It follows that iron overload is a common clinical problem. Therefore, we investigated the effects of iron overload on gene expression in skeletal muscle and heart using microarray technology. Genes with up-regulated expression after iron overload in both skeletal and heart muscle included angiopoietin-like 4, pyruvate dehydrogenase kinase 4 and calgranulin A and B. The expression of transferrin receptor, heat shock protein 1B and DnaJ homolog B1 were down-regulated by iron in both muscle types. Two potential hepcidin regulatory genes, hemojuvelin and neogenin, showed no clear change in expression after iron overload. Concluding, microarray analysis revealed iron-induced changes in the expression of several genes involved in the regulation of glucose and lipid metabolism, transcription and cellular stress responses. These may represent novel connections between iron overload and pathological manifestations of HH such as cardiomyopathy and diabetes. Keywords: iron induced stress response

2007-11-30 | GSE9726 | GEO

NRF2-independent iron-triggered signaling via MAPK p38-ETS1 regulates LSEC Bmp6 mRNA expression [II]

Project description:BMP6 is an iron-sensing cytokine produced by liver sinusoidal endothelial cells (LSECs). The transcription factor NRF2 was proposed to induce Bmp6 expression in response to iron-triggered oxidative stress, and NRF2 knock-out mice were shown not capable of regulating Bmp6 in response to massive diet-imposed iron overload. However, LSEC Bmp6 expression levels in the hemochromatosis mouse model reflect hepatocytic, not endothelial iron content. Hence, it is not fully resolved how iron signals translate into alterations of Bmp6 mRNA levels. To further explore the mechanisms of Bmp6 regulation, we employed female mice aged 10-11 months that are hallmarked by hepatocytic, but not LSEC iron accumulation and decreased transferrin saturation, hinting at the absence of systemic iron overload. We found that LSECs of aged mice exhibit increased Bmp6 levels as compared to young controls, but do not show oxidative stress or a transcriptional signature characteristic of activated NFR2-mediated signaling in FACS-sorted LSECs. We further observed that primary murine LSECs derived from both wild-type and NRF2 knock-out mice induce Bmp6 in response to acute iron exposure. By analyzing RNA sequencing data of FACS-sorted LSECs from aged versus young mice, as well as upon acute injections of iron citrate in young mice, we identified ETS1 as a candidate transcription factor involved in Bmp6 regulation. By conducting siRNA-mediated knock-down and small-molecule treatments in primary LSECs, we show that Bmp6 transcription is regulated in an NRF2-independent manner via ETS1, which is activated downstream of p38 MAP kinase-mediated signaling. This knowledge expands the understanding of Bmp6 transcriptional control in both iron-triggered oxidative stress and under the conditions uncoupled to LSECs reactive oxygen species levels.

2024-01-25 | GSE235975 | GEO

NRF2-independent iron-triggered signaling via MAPK p38-ETS1 regulates LSEC Bmp6 mRNA expression [I]

2024-01-25 | GSE235692 | GEO

Deferasirox in Treating Iron Overload Caused By Blood Transfusions in Patients With Hematologic Malignancies

Project description:RATIONALE: Deferasirox may remove excess iron from the body caused by blood transfusions. PURPOSE: This clinical trial studies deferasirox in treating iron overload caused by blood transfusions in patients with hematologic malignancies.

| 2100588 | ecrin-mdr-crc

scRNA-seq analysis of duodenum CD68+ macrophages from mice where Tsc2 is deleted in Lyz2-expressing cells

Project description:Iron is an essential cellular trace element and important for many physiological functions including erythropoiesis and host defense. It is taken up from the diet in the duodenum, the first part of the small intestine by enterocytes and loaded onto transferrin, the main iron transport molecules in the circulation. Macrophages are ancient sentinel cells that are implicated in all steps of systemic iron metabolism except duodenal iron import. By assessing mice that harbor a macrophage-specific deletion of the tuberous sclerosis complex 2 (Tsc2), a negative regulator of mTORC1, we found that these mice possessed various defects in iron metabolism including defective steady state erythropoiesis and a highly reduced saturation of transferrin with iron. This iron-deficiency phenotype was caused by a block of iron import from the duodenal epithelial cells into the circulation. Activation of mTORC1 in villous duodenal CD68+ macrophages induced expression of serine proteases and promoted local degradation of the major iron transport molecule transferrin, whereas depletion of macrophages in mice increased transferrin levels in the duodenal villi. Inhibition of serine protease activity restored transferrin levels in the Tsc2-deficient mice. Physiologically, transferrin levels were regulated in the villi during Citrobacter rodentium infection in mice. These data show that transferrin is controlled locally in the duodenum and establish macrophages as regulators of duodenal iron uptake.

2023-06-08 | GSE197175 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

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