Mus musculus
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ABSTRACT:
PROVIDER: PRJNA309830 | ENA |
REPOSITORIES: ENA
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Project description:Except for conversion to bile salts, there is no major cholesterol degradation pathway in mammals. Efficient excretion from the body is therefore a crucial element in cholesterol homeostasis. Yet, the existence and importance of these pathways in humans is a matter of debate. We quantified cholesterol fluxes in 15 male volunteers using a cholesterol balance approach. Ten participants repeated the protocol after 4-weeks treatment with ezetimibe, an inhibitor of intestinal and biliary cholesterol absorption. Under basal conditions, about 65% of daily fecal neutral sterol excretion was bile-derived, with the remainder being contributed by direct transintestinal cholesterol excretion (TICE). Surprisingly, ezetimibe induced a fourfold increase in cholesterol elimination via TICE. Mouse studies revealed that most of ezetimibe-induced TICE flux is mediated by the cholesterol transporter Abcg5/Abcg8. In conclusion, TICE is active in humans and may serve as a novel target to stimulate cholesterol elimination in patients at risk for cardiovascular disease.
2016-11-04 | GSE77236 | GEO
Project description:Intake and absorption of cholesterol (the latter determined by double labeled cholesterol methodology) were nearly unchanged in mice fed the saturated fat diet, but the fecal excretion of neutral sterols (i.e. cholesterol and its microbial conversion products) was increased compared with control diet(+80%; p<0.01). The saturated fat diet did neither significantly affect biliary cholesterol secretion nor intestinal cholesterol absorption (49% vs. 65% in controls, double labeled water methodology, p>0.1). Thus, the increased fecal neutral sterol excretion was primarily due to increased net transintestinal cholesterol excretion (+89% versus control; p<0.05). Since a major fraction of TICE cholesterol absorption is normally reabsorbed (J Lipid Res 2019 Sep;60(9):1562-1572), the increased fecal cholesterol excretion could be due to more transintestinal excretion of cholesterol into the intestinal lumen and/or to its decreased reabsorption. The saturated fat diet increased jejunal expression of genes involved in cholesterol synthesis (Srebf2 and target genes), but did not affect whole body de novo cholesterol synthesis. Conclusion This proof-of-principle study shows that increasing the saturation of the dietary fat can stimulate fecal cholesterol excretion. Individual components of saturated fat diets are to be explored to address the responsible molecular mechanisms
2021-02-01 | GSE37097 | GEO
Project description:ABSTRACT Background & aims: The role of the intestine in the maintenance of cholesterol homeostasis is increasingly recognized. Fecal excretion of cholesterol is the last step in the atheroprotective reverse cholesterol transport (RCT) pathway, to which both biliary and transintestinal cholesterol excretion (TICE) contribute. The mechanisms controlling the flux of cholesterol through the TICE pathway are,however, poorly understood. In the current study we aimed to identify treatment modalities that stimulate TICE and to uncover underlying driving mechanisms. Methods: TICE was assessed in a panel of knock-out and transgenic mice as well as in mice treated with the FXR agonist PX20606 either or not combined with the cholesterol absorption inhibitor ezetimibe. Results: We show that TICE is regulated by intestinal farnesoid X receptor (FXR) via its target fibroblast growth factor 15/19 (FGF15/19) and that the pathway can be stimulated to such an extent that mice excrete ~60% of their total cholesterol content each day. Both PX20606 and FGF19 increased the muricholate/cholate ratio in bile, inducing a more hydrophilic bile salt pool. The altered bile salt pool robustly stimulated secretion of cholesterol into the intestinal lumen via the sterol exporting heterodimer ATP binding cassette subfamily G member 5/8 (ABCG5/G8). Of note, we demonstrate that the increase in TICE induced by PX20206 is independent of changes in cholesterol absorption. Conclusions: Hydrophilicity of the bile salt pool, controlled by FXR and FGF15/19, is an important determinant of cholesterol removal via TICE. Translation of these results to humans may offer new treatment modalities for prevention of cardiovascular disease.
2017-01-10 | GSE74101 | GEO
Project description:Background Small intestine and liver greatly contribute to whole body lipid, cholesterol and phospholipid metabolism but to which extent cholesterol and phospholipid handling in these tissues is affected by high fat Western-style obesogenic diets remains to be defined. We therefore quantified cholesterol and phospholipid concentrations in intestine and liver and determined fecal neutral sterol and bile acid excretion in C57Bl/6N mice fed for 12 weeks either a cholesterol-free high carbohydrate control diet or a high fat diet containing 0.03 % (w/w) cholesterol. To identify underlying mechanisms of dietary adaptation in intestine and liver, changes in gene expression were assessed by microarray and qPCR profiling, respectively. Results Animals on high fat diet showed increased plasma cholesterol levels, associated with the higher dietary cholesterol supply, yet, significantly reduced cholesterol levels were found in intestine and liver. Transcript profiling revealed evidence that expression of numerous genes involved in cholesterol synthesis and uptake via LDL, but also in phospholipid metabolism, underwent compensatory regulations in both tissues. Alterations in glycerophospholipid metabolism were confirmed at the metabolite level by phospolipid profiling via mass spectrometry. Conclusions Our findings suggest that intestine and liver react to a high dietary fat intake by an activation of de novo cholesterol synthesis and other cholesterol-saving mechanisms, as well as with major changes in phospholipid metabolism, to accommodate to the fat load. The proximal part of the intestine of mice fed either a control or a high fat diet were analyzed. 5 replicates each.
2011-08-31 | E-GEOD-29748 | biostudies-arrayexpress
Project description:Intestinal cholesterol absorption is an important determinant of systemic cholesterol homeostasis. Niemann-Pick C1 Like 1 (NPC1L1), the target of the drug ezetimibe, is a critical player in dietary cholesterol uptake. But how cholesterol moves within the cell downstream of NPC1L1 is unknown. Here we show that the nonvesicular sterol transporters Aster-B and -C cooperate with NPC1L1 to deliver dietary cholesterol from the gut lumen to the enterocyte ER for chylomicron packaging. Aster proteins are recruited to the enterocyte plasma membrane (PM) in response to NPC1L1-dependent cholesterol accumulation. Mice lacking Asters in intestine have impaired cholesterol absorption, and reduced plasma cholesterol. NanoSIMS imaging and tracer studies reveal delayed lipid trafficking into chylomicrons in Aster-deficient enterocytes. Interestingly, in addition to potently blocking NPC1L1, ezetimibe is also a low-affinity inhibitor of Aster-B and -C but not -A, and the structure of the Aster-C-ezetimibe complex reveals the basis for this selectivity. Our findings support a model in which NPC1L1 enriches dietary cholesterol at the apical PM, and ASTERs subsequently traffic this cholesterol to the ER. The findings identify the enterocyte Aster pathway as potential target for treatment of hypercholesterolemia. Alessandra Ferrari, PhD
2023-12-21 | GSE206780 | GEO
Project description:Background Small intestine and liver greatly contribute to whole body lipid, cholesterol and phospholipid metabolism but to which extent cholesterol and phospholipid handling in these tissues is affected by high fat Western-style obesogenic diets remains to be defined. We therefore quantified cholesterol and phospholipid concentrations in intestine and liver and determined fecal neutral sterol and bile acid excretion in C57Bl/6N mice fed for 12 weeks either a cholesterol-free high carbohydrate control diet or a high fat diet containing 0.03 % (w/w) cholesterol. To identify underlying mechanisms of dietary adaptation in intestine and liver, changes in gene expression were assessed by microarray and qPCR profiling, respectively. Results Animals on high fat diet showed increased plasma cholesterol levels, associated with the higher dietary cholesterol supply, yet, significantly reduced cholesterol levels were found in intestine and liver. Transcript profiling revealed evidence that expression of numerous genes involved in cholesterol synthesis and uptake via LDL, but also in phospholipid metabolism, underwent compensatory regulations in both tissues. Alterations in glycerophospholipid metabolism were confirmed at the metabolite level by phospolipid profiling via mass spectrometry. Conclusions Our findings suggest that intestine and liver react to a high dietary fat intake by an activation of de novo cholesterol synthesis and other cholesterol-saving mechanisms, as well as with major changes in phospholipid metabolism, to accommodate to the fat load.
2011-09-01 | GSE29748 | GEO
Project description:The disruption of cholesterol homeostasis leads to an increase in cholesterol levels which results in the development of cardiovascular disease. Mitogen Inducible Gene 6 (Mig-6) is an immediate early response gene that can be induced by various mitogens, stresses, and hormones. To identify the metabolic role of Mig-6 in the liver, we conditionally ablated Mig-6 in the liver using the Albumin-Cre mouse model (Albcre/+Mig-6f/f; Mig-6d/d). Mig-6d/d mice exhibit hepatomegaly and fatty liver. Serum levels of total, LDL, and HDL cholesterol and hepatic lipid were significantly increased in the Mig-6d/d mice. The daily excretion of fecal bile acids was significantly decreased in the Mig-6d/d mice. DNA microarray analysis of mRNA isolated from the livers of these mice showed alterations in genes that regulate lipid metabolism, bile acid, and cholesterol synthesis, while the expression of genes that regulate biliary excretion of bile acid and triglyceride synthesis showed no difference in the Mig-6d/d mice compared to Mig-6f/f controls. These results indicate that Mig-6 plays an important role in cholesterol homeostasis and bile acid synthesis. Mice with liver specific conditional ablation of Mig-6 develop hepatomegaly and increased intrahepatic lipid and provide a novel model system to investigate the genetic and molecular events involved in the regulation of cholesterol homeostasis and bile acid synthesis. Defining the molecular mechanisms by which Mig-6 regulates cholesterol homeostasis will provide new insights into the development of more effective ways for the treatment and prevention of cardiovascular disease. Eight week old Mig-6f/f vs Mig-6d/d male mice after undergoing a 24 hour fast
2011-08-30 | E-GEOD-31752 | biostudies-arrayexpress
Project description:Intestinal FXR controls transintestinal cholesterol excretion in mice
| PRJNA299006 | ENA
Project description:The disruption of cholesterol homeostasis leads to an increase in cholesterol levels which results in the development of cardiovascular disease. Mitogen Inducible Gene 6 (Mig-6) is an immediate early response gene that can be induced by various mitogens, stresses, and hormones. To identify the metabolic role of Mig-6 in the liver, we conditionally ablated Mig-6 in the liver using the Albumin-Cre mouse model (Albcre/+Mig-6f/f; Mig-6d/d). Mig-6d/d mice exhibit hepatomegaly and fatty liver. Serum levels of total, LDL, and HDL cholesterol and hepatic lipid were significantly increased in the Mig-6d/d mice. The daily excretion of fecal bile acids was significantly decreased in the Mig-6d/d mice. DNA microarray analysis of mRNA isolated from the livers of these mice showed alterations in genes that regulate lipid metabolism, bile acid, and cholesterol synthesis, while the expression of genes that regulate biliary excretion of bile acid and triglyceride synthesis showed no difference in the Mig-6d/d mice compared to Mig-6f/f controls. These results indicate that Mig-6 plays an important role in cholesterol homeostasis and bile acid synthesis. Mice with liver specific conditional ablation of Mig-6 develop hepatomegaly and increased intrahepatic lipid and provide a novel model system to investigate the genetic and molecular events involved in the regulation of cholesterol homeostasis and bile acid synthesis. Defining the molecular mechanisms by which Mig-6 regulates cholesterol homeostasis will provide new insights into the development of more effective ways for the treatment and prevention of cardiovascular disease.
2011-08-31 | GSE31752 | GEO
Project description:Abcg8 knockout mice, fed chow, are infertile. These mice also are susceptible to absorption and retention of xenosterols contained in the diet. Ezetimibe, a blocker of dieary sterol entry, can reverse the fertility in Abcg8 knockout mice. In order to identify if the xenosterols resulted in disruption of a specific set of genes in the testes, we compared wild-type testes, Abcg8 knockout testes, or testes from Abcg8 knockout mice fed chow supplemented with 0.005% ezetimibe. To identify genes of interest, we reasoned that any causative gene expression changes seen in Abcg8 knockout mice fed chow, resulting in xenosterol exposure and accumulation, leading to infertilty, would be reveresed back to a pattern seen in the wild-type mice, when Abcg8 knockout mice are raised on chow containing ezetimibe (which prevents xenosterol absorption in the intestine). The target of this drug, Npc1l1, is not expressed in the testes. Testes from wild-type mice, Abcg8 knockout mice, and Abcg8 knockout mice fed chow supplemented with ezetimibe were analyzed.
2012-08-01 | E-GEOD-39813 | biostudies-arrayexpress