scholarly journals NPC1L1-dependent intestinal cholesterol absorption requires ganglioside GM3 in membrane microdomains

2018 ◽  
Vol 59 (11) ◽  
pp. 2181-2187 ◽  
Author(s):  
Wataru Nihei ◽  
Masakazu Nagafuku ◽  
Hirotaka Hayamizu ◽  
Yuta Odagiri ◽  
Yumi Tamura ◽  
...  
Keyword(s):  
Cholesterol Absorption ◽  
Membrane Microdomains ◽  
Intestinal Cholesterol Absorption ◽  
Ganglioside Gm3

Modulation of intestinal cholesterol absorption by high glucose levels: impact on cholesterol transporters, regulatory enzymes, and transcription factors

2008 ◽  
Vol 295 (5) ◽  
pp. G873-G885 ◽  
Author(s):  
Z. Ravid ◽  
M. Bendayan ◽  
E. Delvin ◽  
A. T. Sane ◽  
M. Elchebly ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Protein Expression ◽  
High Glucose ◽  
Cholesterol Absorption ◽  
Cholesterol Homeostasis ◽  
Cholesterol Transport ◽  
Intestinal Cholesterol Absorption ◽  
Cholesterol Uptake ◽  
Glucose Levels

Growing evidence suggests that the small intestine may contribute to excessive postprandial lipemia, which is highly prevalent in insulin-resistant/Type 2 diabetic individuals and substantially increases the risk of cardiovascular disease. The aim of the present study was to determine the role of high glucose levels on intestinal cholesterol absorption, cholesterol transporter expression, enzymes controlling cholesterol homeostasis, and the status of transcription factors. To this end, we employed highly differentiated and polarized cells (20 days of culture), plated on permeable polycarbonate filters. In the presence of [14C]cholesterol, glucose at 25 mM stimulated cholesterol uptake compared with Caco-2/15 cells supplemented with 5 mM glucose ( P < 0.04). Because combination of 5 mM glucose with 20 mM of the structurally related mannitol or sorbitol did not change cholesterol uptake, we conclude that extracellular glucose concentration is uniquely involved in the regulation of intestinal cholesterol transport. The high concentration of glucose enhanced the protein expression of the critical cholesterol transporter NPC1L1 and that of CD36 ( P < 0.02) and concomitantly decreased SR-BI protein mass ( P < 0.02). No significant changes were observed in the protein expression of ABCA1 and ABCG8, which act as efflux pumps favoring cholesterol export out of absorptive cells. At the same time, 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity was decreased ( P < 0.007), whereas ACAT activity remained unchanged. Finally, increases were noted in the transcription factors LXR-α, LXR-β, PPAR-β, and PPAR-γ along with a drop in the protein expression of SREBP-2. Collectively, our data indicate that glucose at high concentrations may regulate intestinal cholesterol transport and metabolism in Caco-2/15 cells, thus suggesting a potential influence on the cholesterol absorption process in Type 2 diabetes.

Intestinal cholesterol absorption

2018 ◽  
Vol 29 (6) ◽  
pp. 484-485 ◽  
Author(s):  
Maaike Kockx ◽  
Leonard Kritharides
Keyword(s):  
Cholesterol Absorption ◽  
Intestinal Cholesterol Absorption

scholarly journals A role for NPC1 and NPC2 in intestinal cholesterol absorption – the hypothesis gutted

2007 ◽  
Vol 408 (1) ◽  
Author(s):  
Laura Liscum
Keyword(s):  
Endoplasmic Reticulum ◽  
Dietary Cholesterol ◽  
Cholesterol Absorption ◽  
Cholesterol Transport ◽  
Intestinal Epithelial ◽  
Intestinal Cholesterol Absorption ◽  
Biochemical Journal ◽  
Good Target ◽  
Type C ◽  
Niemann Pick

Dietary and biliary cholesterol are taken up by intestinal epithelial cells and transported to the endoplasmic reticulum. At the endoplasmic reticulum, cholesterol is esterified, packaged into chylomicrons and secreted into the lymph for delivery to the bloodstream. NPC1L1 (Niemann–Pick C1-like 1) is a protein on the enterocyte brush-border membrane that facilitates cholesterol absorption. Cholesterol's itinerary as it moves to the endoplasmic reticulum is unknown, as is the identity of any cellular proteins that facilitate the movement. Two proteins that play an important role in intracellular cholesterol transport and could potentially influence NPC1L1-mediated cholesterol uptake are NPC1 and NPC2 (Niemann–Pick type C disease proteins 1 and 2). In this issue of the Biochemical Journal, Dixit and colleagues show that the absence or presence of NPC1 and NPC2 has no effect on intestinal cholesterol absorption in the mouse. Thus neither protein fills the gap in our knowledge of intra-enterocyte cholesterol transport. Furthermore, the NPC1/NPC2 pathway would not be a good target for limiting the uptake of dietary cholesterol.

Effect of alfalfa saponins on intestinal cholesterol absorption in rats

1977 ◽  
Vol 30 (12) ◽  
pp. 2061-2067 ◽  
Author(s):  
M R Malinow ◽  
P McLaughlin ◽  
L Papworth ◽  
C Stafford ◽  
G O Kohler ◽  
...  
Keyword(s):  
Cholesterol Absorption ◽  
Intestinal Cholesterol Absorption

scholarly journals Mechanisms of cholesterol-lowering effects of dietary insoluble fibres: relationships with intestinal and hepatic cholesterol parameters

2005 ◽  
Vol 94 (3) ◽  
pp. 331-337 ◽  
Author(s):  
Ariëtte M. van Bennekum ◽  
David V. Nguyen ◽  
Georg Schulthess ◽  
Helmut Hauser ◽  
Michael C. Phillips
Keyword(s):  
Bile Acid ◽  
Food Intake ◽  
Serum Cholesterol ◽  
Cholesterol Absorption ◽  
Cholesterol Homeostasis ◽  
Hepatic Cholesterol ◽  
Intestinal Cholesterol Absorption ◽  
Cholesterol Lowering ◽  
Dietary Fibres ◽  
Bile Acid Binding

Fibres with a range of abilities to perturb cholesterol homeostasis were used to investigate how the serum cholesterol-lowering effects of insoluble dietary fibres are related to parameters of intestinal cholesterol absorption and hepatic cholesterol homeostasis in mice. Cholestyramine, chitosan and cellulose were used as examples of fibres with high, intermediate and low bile acid-binding capacities, respectively. The serum cholesterol levels in a control group of mice fed a high fat/high cholesterol (HFHC) diet for 3 weeks increased about 2-fold to 4·3 mm and inclusion of any of these fibres at 7·5 % of the diet prevented this increase from occurring. In addition, the amount of cholesterol accumulated in hepatic stores due to the HFHC diet was reduced by treatment with these fibres. The three kinds of fibres showed similar hypocholesterolaemic activity; however, cholesterol depletion of liver tissue was greatest with cholestyramine. The mechanisms underlying the cholesterol-lowering effect of cholestyramine were (1) decreased cholesterol (food) intake, (2) decreased cholesterol absorption efficiency, and (3) increased faecal bile acid and cholesterol excretion. The latter effects can be attributed to the high bile acid-binding capacity of cholestyramine. In contrast, incorporation of chitosan or cellulose in the diet reduced cholesterol (food) intake, but did not affect either intestinal cholesterol absorption or faecal sterol output. The present study provides strong evidence that above all satiation and satiety effects underlie the cholesterol-lowering properties of insoluble dietary fibres with moderate or low bile acid-binding capabilities.

scholarly journals A new aspect on the mechanism of intestinal cholesterol absorption in rat.

1981 ◽  
Vol 27 (3) ◽  
pp. 209-217 ◽  
Author(s):  
Makoto WATANABE ◽  
Tsuneyuki OKU ◽  
Yoshihiro SHIDOJI ◽  
Norimasa HOSOYA
Keyword(s):  
Cholesterol Absorption ◽  
Intestinal Cholesterol Absorption

Abstract 617: Intestine-Specific MTP Deficiency with ACAT2 Gene Ablation Lowers Acute Cholesterol Absorption With Chylomicrons and High-Density Lipoproteins

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Jahangir Iqbal ◽  
Mohamed Boutjdir ◽  
Lawrence L Rudel ◽  
M Mahmood Hussain
Keyword(s):  
Density Lipoprotein ◽  
Microsomal Triglyceride Transfer Protein ◽  
Cholesterol Absorption ◽  
High Density ◽  
High Density Lipoproteins ◽  
High Cholesterol ◽  
Intestinal Cholesterol Absorption ◽  
Triglyceride Accumulation ◽  
Abca1 Expression ◽  
Deficient Mice

Intestinal cholesterol absorption involves chylomicron and high density lipoprotein (HDL) pathways. Microsomal triglyceride transfer protein (MTP) and ATP binding cassette family A protein 1 (ABCA1) are critical for cholesterol transport by these pathways, respectively. Additionally, acyl Co-A:cholesterol acyltransferase 2 (ACAT2) plays an important role in cholesterol absorption. Intestinal MTP ablation significantly increased intestinal triglyceride and cholesterol levels and reduced their acute absorption. In contrast, ACAT2 deficiency had no effect on triglyceride absorption but significantly reduced cholesterol absorption. Individual deficiencies of ACAT2 and MTP reduced cholesterol absorption with chylomicrons. We hypothesized that their combined deficiency would increase cholesterol secretion with HDL; unexpectedly, their deficiency reduced secretion with both chylomicrons and HDL. Further, we observed significant reductions in intestinal ABCA1 expression in combined deficient mice. Thus, free cholesterol is unavailable for secretion by the HDL pathway in these mice. We speculate that reductions in ABCA1 expression and HDL secretion might be secondary to massive triglyceride accumulation associated with intestinal MTP deficiency. Besides its role in cholesterol absorption, ACAT2 deficiency causes mild hypertriglyceridemia and reduces steatosis in mice fed high cholesterol diets by increasing hepatic lipoprotein production by unknown mechanisms. We show that this phenotype is preserved in the absence of intestinal MTP in ACAT2 deficient mice fed a Western diet. Further, we observed increases in hepatic MTP activity in these mice. Thus, ACAT2 deficiency might increase MTP expression to avoid steatosis. Therefore, ACAT2 inhibition might avert steatosis associated with high cholesterol diets by increasing MTP expression.

scholarly journals Effects of spirulina and wakame consumption on intestinal cholesterol absorption and serum lipid concentrations in non-hypercholesterolemic adult men and women

2019 ◽  
Vol 59 (5) ◽  
pp. 2229-2236
Author(s):  
José J. van den Driessche ◽  
Jogchum Plat ◽  
Maurice C. J. M. Konings ◽  
Ronald P. Mensink
Keyword(s):  
Serum Lipid ◽  
Cholesterol Absorption ◽  
Intestinal Cholesterol Absorption ◽  
Men And Women ◽  
Adult Men
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