Search results for "lxr"
showing 10 items of 11 documents
Muricholic Acids Promote Resistance to Hypercholesterolemia in Cholesterol-Fed Mice
2021
International audience; Background and aims: Hypercholesterolemia is a major risk factor for atherosclerosis and cardiovascular diseases. Although resistant to hypercholesterolemia, the mouse is a prominent model in cardiovascular research. To assess the contribution of bile acids to this protective phenotype, we explored the impact of a 2-week-long dietary cholesterol overload on cholesterol and bile acid metabolism in mice. Methods: Bile acid, oxysterol, and cholesterol metabolism and transport were assessed by quantitative real-time PCR, western blotting, GC-MS/MS, or enzymatic assays in the liver, the gut, the kidney, as well as in the feces, the blood, and the urine. Results: Plasma tr…
LXR, prostate cancer and cholesterol: the Good, the Bad and the Ugly.
2012
International audience; Cholesterol is a fundamental molecule for life. Located in the cell membrane, this sterol participates to the cell signaling of growth factors. Inside the cell it can be converted in hormones such as androgens or modulate the immune response. Such important functions could not be solely dependent of external supply by diet hence de novo synthesis could occur from acetate in almost all mammalian cells. If a deficiency in cholesterol sourcing leads to development troubles, overstocking has been associated to various diseases such as atherosclerosis and cancers. Cholesterol homeostasis should thus be tightly regulated at the uptake, de novo synthesis, storage and export…
Caspase-1 involvement in colorectal cancer cell death phenomenons
2014
Colon cancer is a major public health matter because it has reached the second rank of cancer mortality in 2013 in France. Surgery, radiotherapy and standard chemotherapies helped by targeted therapies are not often efficient enough, underlying the need of using new therapies.Against this background, we have studied the possibilities to use new therapies (Liver X Receptor (LXR) ligands) or to improve classical treatment conditions (hyperthermic intraperitoneal chemotherapy (HIPC)) and the implication of caspase-1.We have first demonstrated that the nuclear receptor (LXR) agonists can induce pyroptotic cell death of colon cancer cell lines by inflammasome activation and subsequent caspase-1 …
Liver X Receptor ligand cytotoxicity in colon cancer cells and not in normal colon epithelial cells depends on LXRβ subcellular localization
2015
Increasing evidence indicates that Liver X Receptors (LXRs) have some anticancer properties. We recently demonstrated that LXR ligands induce colon cancer cell pyroptosis through an LXRβ-dependent pathway. In the present study, we showed that human colon cancer cell lines presented differential cytoplasmic localizations of LXRβ. This localization correlated with caspase-1 activation and cell death induction under treatment with LXR ligand. The association of LXRβ with the truncated form of RXRα (t-RXRα) was responsible for the sequestration of LXRβ in the cytoplasm in colon cancer cells. Moreover t-RXRα was not expressed in normal colon epithelial cells. These cells presented a predominantl…
Lack of Correlation of Plasma HDL With Fecal Cholesterol and Plasma Cholesterol Efflux Capacity Suggests Importance of HDL Functionality in Attenuati…
2018
A number of clinical findings suggested HDL-raising as a plausible approach to treat residual risk of CVD. However, lack of CVD risk reduction by elevated HDL cholesterol (HDL-C) through cholesterol ester transfer protein (CETP) inhibition and enhanced risk reduction in apolipoprotein A-I Milano (apoAI-M) individuals with low HDL-C shifted the focus from HDL-C level to HDL function. In the present study, we investigated correlations between HDL-C, HDL function, fecal cholesterol excretion, and ex vivo plasma cholesterol efflux capacity (CEC) in animal models using two HDL modulators, LXR and PPAR-α agonists. In C57Bl mice, LXR agonist, T1317, raised HDL-C by 30%, while PPAR-α agonist, fenof…
LXR antagonists induce ABCD2 expression
2014
X-linked adrenoleukodystrophy (X-ALD) is a rare neurodegenerative disorder characterized by the accumulation of very-long-chain fatty acids resulting from a beta-oxidation defect. Oxidative stress and inflammation are also key components of the pathogenesis. X-ALD is caused by mutations in the ABCDI gene, which encodes for a peroxisomal half ABC transporter predicted to participate in the entry of VLCFA-CoA into the peroxisome, the unique site of their beta-oxidation. Two homologous peroxisomal ABC transporters, ABCD2 and ABCD3 have been proven to compensate for ABCD1 deficiency when overexpressed. Pharmacological induction of these target genes could therefore represent an alternative ther…
Insulin Dissociates the Effects of Liver X Receptor on Lipogenesis, Endoplasmic Reticulum Stress, and Inflammation
2016
IF 4.258; International audience; Diabetes is characterized by increased lipogenesis as well as increased endoplasmic reticulum (ER) stress and inflammation. The nuclear hormone receptor liver X receptor (LXR) is induced by insulin and is a key regulator of lipid metabolism. It promotes lipogenesis and cholesterol efflux, but suppresses endoplasmic reticulum stress and inflammation. The goal of these studies was to dissect the effects of insulin on LXR action. We used antisense oligonucleotides to knock down Lxr alpha in mice with hepatocytespecific deletion of the insulin receptor and their controls. We found, surprisingly, that knock-out of the insulin receptor and knockdown of Lxr alpha …
Biological activities of Schottenol and Spinasterol, two natural phytosterols present in argan oil and in cactus pear seed oil, on murine miroglial B…
2014
International audience; The objective of this study was to evaluate the biological activities of the major phytosterols present in argan oil (AO) and in cactus seed oil (CSO) in BV2 microglial cells. Accordingly, we first determined the sterol composition of AO and CSO, showing the presence of Schottenol and Spinasterol as major sterols in AO. While in CSO, in addition to these two sterols, we found mainly another sterol, the Sitosterol. The chemical synthesis of Schottenol and Spinasterol was performed. Our results showed that these two phytosterols, as well as sterol extracts from AO or CSO, are not toxic to microglial BV2 cells. However, treatments by these phytosterols impact the mitoch…
Role of LECT2 in non alcoholic fatty liver disease
2020
The liver is the privileged site of metabolic regulations that must be tightly coordinated to prevent metabolic imbalance to preserve homeostasis. Alteration of these processes can promote steatosis, an essential feature of Non-Alcoholic Fatty Liver Diseases (NAFLD), representing the new global epidemic threat. During this thesis work, we demonstrated that LECT2, a liver secreted factor, is increased in both Human and mice harboring fatty liver. In a physiological context, we demonstrated that LECT2 controls liver lipogenesis through the LXR signalling pathway. At the molecular level, the absence of LECT2 induces a specific accumulation of 25-OHC oxysterol which leads to a significant incre…
Induction of pyroptosis in colon cancer cells by LXRβ.
2014
Liver X receptors (LXRs) have been proposed to have some anticancer properties. We recently identified a new non-genomic role of LXRβ in colon cancer cells. Under LXR agonist treatment, LXRβ induces pyroptosis of these cells in vitro and in vivo, raising the possibility of targeting this isoform in cancer treatment.