In vitro, in vivo studies of a new amphiphilic adsorbent for the removal of low-density lipoprotein

Niemann-Pick C1-Like 1 (NPC1L1) is a cholesterol importer and target of ezetimibe, a cholesterol absorption inhibitor used clinically for dyslipidemia. Recent studies demonstrated that NPC1L1 regulates the intestinal absorption of several fat-soluble nutrients, in addition to cholesterol. The study was conducted to reveal new physiological roles of NPC1L1 by identifying novel dietary substrate(s). Very low-density lipoprotein and low-density lipoprotein (VLDL/LDL) are increased in Western diet (WD)-fed mice in an NPC1L1-dependent manner, so we comprehensively analyzed the NPC1L1-dependent VLDL/LDL components. Apolipoprotein M (apoM), a binding protein of sphingosine-1-phosphate (S1P: a lipid mediator), and S1P were NPC1L1-dependently increased in VLDL/LDL by WD feeding. S1P is metabolized from sphingomyelin (SM) and SM is abundant in WD, so we focused on intestinal SM absorption. In vivo studies with Npc1l1 knockout mice and in vitro studies with NPC1L1-overexpressing cells revealed that SM is a physiological substrate of NPC1L1. These results suggest a scenario in which dietary SM is absorbed by NPC1L1 in the intestine, followed by SM conversion to S1P and, after several steps, S1P is exported into the blood as the apoM-bound form in VLDL/LDL. Our findings provide insight into the functions of NPC1L1 for a better understanding of sphingolipids and S1P homeostasis.

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Transfer of newly made triglyceride from hepatocytes to preexisting extracellular very low density lipoproteins

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y87-058 ◽

1987 ◽

Vol 65 (3) ◽

pp. 337-343

Author(s):

Gen Yoshino ◽

George Steiner

Keyword(s):

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Liver Cells ◽

Low Density Lipoproteins ◽

In Vivo Studies ◽

Low Density ◽

Very Low Density Lipoproteins ◽

Apoprotein B

Previous in vivo studies suggested a new model to describe the metabolism of very low density lipoproteins (VLDL). It was hypothesized that some of the lipoprotein triglyceride was transferred directly from hepatocytes and intestinal mucosal cells into preexisting extracellular VLDL particles. These studies employ an in vitro system to test this hypothesis. Isolated rat liver cells containing newly made radioactive triglyceride were prepared. These cells were incubated in medium to which exogenous VLDL had or had not been added. The presence of extracellular VLDL (rat or human) stimulated the transfer of labeled triglyceride out of the liver cells. This triglyceride was recovered in the medium's VLDL (as determined by its density and its precipitability by MnCl2–heparin or by anti-apoprotein B). Although these studies focussed on VLDL, preliminary data showed that similar triglyceride transfer occurred in the presence of the other apoprotein B containing lipoprotein, low density lipoprotein (LDL). However, in the presence of equivalent amounts of LDL, this triglyceride transfer was less than that seen in the presence of exogenous VLDL. Furthermore, the increased triglyceride released in the presence of LDL occurred entirely in the d < 1.006 fraction of the medium. That released in the presence of VLDL was recovered in the d > 1.006 fraction. Hence, we conclude that the transfer of the newly made triglyceride was from the cell to the extracellular lipoprotein that had been added to the medium. The transfer of triglyceride to VLDL did not depend on the synthesis and release of new VLDL particles because it was not accompanied by a change in the production of [14C]leucine VLDL protein, it was not blocked by chloroquine, and the LDL induced triglyceride release occurred into the d > 1.006 fraction. This transfer did not depend on the previously described triglyceride-transfer factor. The present in vitro studies support the model suggested by our earlier in vivo studies. The VLDL particle does not appear to be metabolized as a complete intact unit. Rather, some of its major lipid component, triglyceride, can move directly into and out of already existing extracellular lipoproteins.

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Lovastatin inhibits low-density lipoprotein oxidation and alters its fluidity and uptake by macrophages: In vitro and in vivo studies

Metabolism ◽

10.1016/0026-0495(92)90263-a ◽

1992 ◽

Vol 41 (3) ◽

pp. 229-235 ◽

Cited By ~ 105

Author(s):

Michael Aviram ◽

Gertrude Dankner ◽

Uri Cogan ◽

Edna Hochgraf ◽

J.Gerald Brook

Keyword(s):

Low Density Lipoprotein ◽

Density Lipoprotein ◽

In Vivo Studies ◽

Low Density ◽

Lipoprotein Oxidation ◽

Low Density Lipoprotein Oxidation

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Reductions of copper ion-mediated low-density lipoprotein (LDL) oxidations of trypsin inhibitors, the sweet potato root major proteins, and LDL binding capacities

Botanical Studies ◽

10.1186/s40529-020-00303-4 ◽

2020 ◽

Vol 61 (1) ◽

Author(s):

Yeh-Lin Lu ◽

Chia-Jung Lee ◽

Shyr-Yi Lin ◽

Wen-Chi Hou

Keyword(s):

Sweet Potato ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Trypsin Inhibitors ◽

Water Soluble ◽

Affinity Column ◽

Low Density ◽

Native Page

Abstract Background The root major proteins of sweet potato trypsin inhibitors (SPTIs) or named sporamin, estimated for 60 to 80% water-soluble proteins, exhibited many biological activities. The human low-density lipoprotein (LDL) showed to form in vivo complex with endogenous oxidized alpha-1-antitrypsin. Little is known concerning the interactions between SPTIs and LDL in vitro. Results The thiobarbituric-acid-reactive-substance (TBARS) assays were used to monitor 0.1 mM Cu2+-mediated low-density lipoprotein (LDL) oxidations during 24-h reactions with or without SPTIs additions. The protein stains in native PAGE gels were used to identify the bindings between native or reduced forms of SPTIs or soybean TIs and LDL, or oxidized LDL (oxLDL). It was found that the SPTIs additions showed to reduce LDL oxidations in the first 6-h and then gradually decreased the capacities of anti-LDL oxidations. The protein stains in native PAGE gels showed more intense LDL bands in the presence of SPTIs, and 0.5-h and 1-h reached the highest one. The SPTIs also bound to the oxLDL, and low pH condition (pH 2.0) might break the interactions revealed by HPLC. The LDL or oxLDL adsorbed onto self-prepared SPTIs-affinity column and some components were eluted by 0.2 M KCl (pH 2.0). The native or reduced SPTIs or soybean TIs showed different binding capacities toward LDL and oxLDL in vitro. Conclusion The SPTIs might be useful in developing functional foods as antioxidant and nutrient supplements, and the physiological roles of SPTIs-LDL and SPTIs-oxLDL complex in vivo will investigate further using animal models.

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Translation in vivo and in vitro of proteins resembling apoproteins of rat plasma very low density lipoprotein.

The Journal of Lipid Research ◽

10.1016/s0022-2275(20)40616-9 ◽

1979 ◽

Vol 20 (3) ◽

pp. 334-348

Author(s):

R Hay ◽

G S Getz

Keyword(s):

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Rat Plasma ◽

Very Low Density Lipoprotein ◽

Low Density

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Sagunja-Tang Improves Lipid Related Disease in a Postmenopausal Rat Model and HepG2 Cells

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2015/321407 ◽

2015 ◽

Vol 2015 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Hiroe Go ◽

Jin Ah Ryuk ◽

Hye Won Lee ◽

In Sil Park ◽

Ki-Jung Kil ◽

...

Keyword(s):

Lipid Accumulation ◽

Hepg2 Cells ◽

Cholesterol Synthesis ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Low Density ◽

Protein Levels ◽

Related Disease

The present study was conducted to investigate the effect of Sagunja-tang on the lipid related disease in a rat model of menopausal hyperlipidemia and lipid accumulation in methyl-β-cyclodextrin-induced HepG2 cells. Inin vivostudy using menopausal hyperlipidemia rats, Sagunja-tang reduced retroperitoneal and perirenal fat, serum lipids, atherogenic index, cardiac risk factor, media thickness, and nonalcoholic steatohepatitis score, when compared to menopausal hyperlipidemia control rats. In HepG2 cells, Sagunja-tang significantly decreased the lipid accumulation, total cholesterol levels, and low-density/very-low-density lipoprotein levels. Moreover, Sagunja-tang reversed the methyl-β-cyclodextrin-induced decrease in the protein levels of critical molecule involved in cholesterol synthesis, sterol regulatory element binding protein-2, and low-density lipoprotein receptor and inhibited protein levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase as well as activity. Phosphorylation level of AMP-activated protein kinase was stimulated by Sagunja-tang. These results suggest that Sagunja-tang has effect on inhibiting hepatic lipid accumulation through regulation of cholesterol synthesis and AMPK activityin vitro. These observations support the idea that Sagunja-tang is bioavailable bothin vivoandin vitroand could be developed as a preventive and therapeutic agent of hyperlipidemia in postmenopausal females.

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