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Lee H, Shin E, Kang H, Youn H, Youn B. Soybean-Derived Peptides Attenuate Hyperlipidemia by Regulating Trans-Intestinal Cholesterol Excretion and Bile Acid Synthesis. Nutrients 2021; 14:95. [PMID: 35010970 PMCID: PMC8747086 DOI: 10.3390/nu14010095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/23/2021] [Accepted: 12/24/2021] [Indexed: 11/16/2022] Open
Abstract
Increased triglyceride, cholesterol, and low-density lipoprotein (LDL) levels cause hyperlipidemia. Despite the availability of statin-based drugs to reduce LDL levels, additional effective treatments for reducing blood lipid concentrations are required. Herein, soybean hydrolysate prepared via peptic and tryptic hydrolysis promoted trans-intestinal cholesterol excretion (TICE) by increasing ATP-binding cassette subfamily G member 5 (ABCG5) and ABCG8 expression. The peptide sequence capable of promoting TICE was determined via HPLC and LC-MS/MS. Based on this, pure artificial peptides were synthesized, and the efficacy of the selected peptides was verified using cellular and hyperlipidemic mouse models. Soybean hydrolysates, including two bioactive peptides (ALEPDHRVESEGGL and SLVNNDDRDSYRLQSGDAL), promoted TICE via the expression of ABCG5 and ABCG8 in enterocytes. They downregulated expression of hepatic cytochrome P450 family 7 subfamily A member 1 (CYP7A1) and CYP8B1 via expression of fibroblast growth factor 19 (FGF19) in a liver X receptor α (LXRa)-dependent pathway. Administration of bioactive peptides to hyperlipidemic mouse models by oral gavage reduced cholesterol levels in serum via upregulation of ABCG5 and ABCG8 expression in the proximal intestine and through fecal cholesterol excretion, upregulated FGF 15/19 expression, and suppressed hepatic bile acid synthesis. Oral administration of soybean-derived bioactive peptides elicited hypolipidemic effects by increasing TICE and decreasing hepatic cholesterol synthesis.
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Affiliation(s)
- Haksoo Lee
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea; (H.L.); (E.S.); (H.K.)
| | - Eunguk Shin
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea; (H.L.); (E.S.); (H.K.)
| | - Hyunkoo Kang
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea; (H.L.); (E.S.); (H.K.)
| | - HyeSook Youn
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul 05006, Korea
| | - BuHyun Youn
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea; (H.L.); (E.S.); (H.K.)
- Department of Biological Sciences, Pusan National University, Busan 46241, Korea
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Hong J, Kim M, Kim B. The Effects of Anthocyanin-Rich Bilberry Extract on Transintestinal Cholesterol Excretion. Foods 2021; 10:2852. [PMID: 34829135 DOI: 10.3390/foods10112852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/13/2021] [Accepted: 11/15/2021] [Indexed: 11/17/2022] Open
Abstract
Hypercholesterolemia is one of the modifiable and primary risk factors for cardiovascular diseases (CVD). Emerging evidence suggests the stimulation of transintestinal cholesterol excretion (TICE), the nonbiliary cholesterol excretion, using natural products can be an effective way to reduce CVD. Bilberry (Vaccinium myrtillus L.) has been reported to have cardioprotective effects by ameliorating oxidative stress, inflammation, and dyslipidemia. However, the role of bilberry in intestinal cholesterol metabolism is not well understood. To examine the effects of bilberry in intestinal cholesterol metabolism, we measured the genes for cholesterol flux and de novo synthesis in anthocyanin-rich bilberry extract (BE)-treated Caco-2 cells. BE significantly decreased the genes for cholesterol absorption, i.e., Niemann-Pick C1 Like 1 and ATP-binding cassette transporter A1 (ABCA1). In contrast, BE significantly upregulated ABCG8, the apical transporter for cholesterol. There was a significant induction of low-density lipoprotein receptors, with a concomitant increase in cellular uptake of cholesterol in BE-treated cells. The expression of genes for lipogenesis and sirtuins was altered by BE treatment. In the present study, BE altered the genes for cholesterol flux from basolateral to the apical membrane of enterocytes, potentially stimulating TICE. These results support the potential of BE in the prevention of hypercholesterolemia.
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Lee S, Youn B. Hypolipidemic Roles of Casein-Derived Peptides by Regulation of Trans-Intestinal Cholesterol Excretion and Bile Acid Synthesis. Nutrients 2020; 12:nu12103058. [PMID: 33036208 PMCID: PMC7600240 DOI: 10.3390/nu12103058] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/02/2020] [Accepted: 10/05/2020] [Indexed: 12/16/2022] Open
Abstract
Hyperlipidemia, a syndrome characterized by an abnormal elevation of blood lipids, causes chronic lethal metabolic disorders. Although statins are regularly prescribed to patients, an alternative to treat the burden of excessive lipids is required for cholesterol control. In this study, it was found that the treatment of casein hydrolyzed by pepsin and trypsin induced trans-intestinal cholesterol excretion (TICE) through ATP-binding cassette subfamily G members 5 (ABCG5) expression. Next, we analyzed sequences of the peptides responsible for TICE induction, synthesized artificial peptides based on the sequences, and the hypolipidemic effects of the peptide treatments were assessed in both in vitro and in vivo models. We determined that two bioactive peptides contained in casein hydrolysates (SQSKVLPVPQK and HPHPHLSF) induced TICE through the expression of ABCG5 in enterocytes and suppressed hepatic mRNA expression of cytochrome P450 family 7 subfamily A member 1 (CYP7A1) and CYP8B1by ileal FGF19 expression both in an liver X receptor α (LXRα)-mediated manner. In the hyperlipidemic mouse models, the oral administration of peptides reduced serum cholesterol levels through elevation of the ABCG5 expression in proximal intestine and fecal cholesterol secretion. Besides this, peptides induced ileal expression of fibroblast growth factor 15/19 (FGF15/19) and inhibited hepatic bile acid synthesis. We found that the oral treatment of casein-derived bioactive peptides could improve hyperlipidemia by regulating intestinal excretion and hepatic synthesis of cholesterols.
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Affiliation(s)
- Sungmin Lee
- Nuclear Science Research Institute, Pusan National University, Busan 46241, Korea;
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea
| | - BuHyun Youn
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea
- Department of Biological Sciences, Pusan National University, Busan 46241, Korea
- Correspondence: ; Tel.: +82-51-510-2264; Fax: +82-51-581-2962
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de Boer JF, Verkade E, Mulder NL, de Vries HD, Huijkman N, Koehorst M, Boer T, Wolters JC, Bloks VW, van de Sluis B, Kuipers F. A human-like bile acid pool induced by deletion of hepatic Cyp2c70 modulates effects of FXR activation in mice. J Lipid Res 2019; 61:291-305. [PMID: 31506275 PMCID: PMC7053831 DOI: 10.1194/jlr.ra119000243] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/05/2019] [Indexed: 01/12/2023] Open
Abstract
Bile acids (BAs) facilitate intestinal absorption of lipid-soluble nutrients and modulate various metabolic pathways through the farnesoid X receptor (FXR) and Takeda G-protein-coupled receptor 5. These receptors are targets for therapy in cholestatic and metabolic diseases. However, dissimilarities in BA metabolism between humans and mice complicate translation of preclinical data. Cytochrome P450 family 2 subfamily c polypeptide 70 (CYP2C70) was recently proposed to catalyze the formation of rodent-specific muricholic acids (MCAs). With CRISPR/Cas9-mediated somatic genome editing, we generated an acute hepatic Cyp2c70 knockout mouse model (Cyp2c70ako) to clarify the role of CYP2C70 in BA metabolism in vivo and evaluate whether its activity modulates effects of pharmacologic FXR activation on cholesterol homeostasis. In Cyp2c70ako mice, chenodeoxycholic acid (CDCA) increased at the expense of βMCA, resulting in a more hydrophobic human-like BA pool. Tracer studies demonstrated that, in vivo, CYP2C70 catalyzes the formation of βMCA primarily by sequential 6β-hydroxylation and C7-epimerization of CDCA, generating αMCA as an intermediate metabolite. Physiologically, the humanized BA composition in Cyp2c70ako mice blunted the stimulation of fecal cholesterol disposal in response to FXR activation compared with WT mice, predominantly due to reduced stimulation of transintestinal cholesterol excretion. Thus, deletion of hepatic Cyp2c70 in adult mice translates into a human-like BA pool composition and impacts the response to pharmacologic FXR activation. This Cyp2c70ako mouse model may be a useful tool for future studies of BA signaling and metabolism that informs human disease development and treatment.
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Affiliation(s)
- Jan Freark de Boer
- Departments of Laboratory Medicine University Medical Center Groningen, University of Groningen, Groningen, The Netherlands .,Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Esther Verkade
- Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Niels L Mulder
- Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Hilde D de Vries
- Departments of Laboratory Medicine University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,iPSC/CRISPR Center Groningen, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Nicolette Huijkman
- Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,University of Groningen, Campus Fryslân, Leeuwarden, The Netherlands
| | - Martijn Koehorst
- Departments of Laboratory Medicine University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Theo Boer
- Departments of Laboratory Medicine University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Justina C Wolters
- Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Vincent W Bloks
- Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Bart van de Sluis
- Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,University of Groningen, Campus Fryslân, Leeuwarden, The Netherlands
| | - Folkert Kuipers
- Departments of Laboratory Medicine University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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van de Peppel IP, Bertolini A, van Dijk TH, Groen AK, Jonker JW, Verkade HJ. Efficient reabsorption of transintestinally excreted cholesterol is a strong determinant for cholesterol disposal in mice. J Lipid Res 2019; 60:1562-1572. [PMID: 31324653 PMCID: PMC6718438 DOI: 10.1194/jlr.m094607] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/19/2019] [Indexed: 11/20/2022] Open
Abstract
Transintestinal cholesterol excretion (TICE) is a major route for eliminating cholesterol from the body and a potential therapeutic target for hypercholesterolemia. The underlying mechanism, however, is largely unclear, and its contribution to cholesterol disposal from the body is obscured by the counteracting process of intestinal cholesterol reabsorption. To determine the quantity of TICE independent from its reabsorption, we studied two models of decreased intestinal cholesterol absorption. Cholesterol absorption was inhibited either by ezetimibe or, indirectly, by the genetic inactivation of the intestinal apical sodium-dependent bile acid transporter (ASBT; SLC10A2). Both ezetimibe treatment and Asbt inactivation virtually abrogated fractional cholesterol absorption (from 46% to 4% and 6%, respectively). In both models, fecal neutral sterol excretion and net intestinal cholesterol balance were considerably higher than in control mice (5- and 7-fold, respectively), suggesting that, under physiological conditions, TICE is largely reabsorbed. In addition, the net intestinal cholesterol balance was increased to a similar extent but was not further increased when the models were combined, suggesting that the effect on cholesterol reabsorption was already maximal under either condition alone. On the basis of these findings, we hypothesize that the inhibition of cholesterol (re)absorption combined with stimulating TICE will be most effective in increasing cholesterol disposal.
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Affiliation(s)
- Ivo P van de Peppel
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics,University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Anna Bertolini
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics,University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Theo H van Dijk
- Department of Laboratory Medicine University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Albert K Groen
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics,University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Laboratory of Experimental Vascular Medicine University of Amsterdam, Academic Medical Center, Amsterdam, The Netherlands
| | - Johan W Jonker
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics,University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - Henkjan J Verkade
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics,University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
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Abstract
Besides the well-known hepatobiliary pathway of cholesterol excretion into the feces, transintestinal cholesterol excretion (TICE) is a second major pathway through which cholesterol is disposed from the body. In the process of TICE, cholesterol is taken up from lipoprotein particles at the basolateral side of the enterocyte and translocates towards the apical side of the enterocyte. At the apical side, the ATP-binding cassette transporters G5 and G8 form a heterodimer that transports cholesterol into the intestinal lumen. A substantial amount of the secreted cholesterol is likely reabsorbed by the cholesterol influx transporter Niemann-Pick C1-Like 1 (NPC1L1) since recent data indicate that inhibition of NPC1L1 increases the efficacy of TICE for disposal of cholesterol via the feces. The pathways and proteins involved in intracellular cholesterol trafficking in the enterocyte have not yet been identified. Therefore, in addition to discussing known mediators of TICE, this review will also examine potential candidates involved in cholesterol translocation in the enterocyte. Both the cholesterol reuptake and efflux pathways can be influenced by pharmaceutical means; thus, the TICE pathway is a very attractive target to increase cholesterol excretion from the body and prevent or mitigate atherosclerotic cardiovascular disease.
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Affiliation(s)
- Aldo Grefhorst
- AMSTERDAM UNIVERSITY MEDICAL CENTERS, AMSTERDAM, THE NETHERLANDS
| | - Henkjan J Verkade
- UNIVERSITY MEDICAL CENTER GRONINGEN, UNIVERSITY OF GRONINGEN, GRONINGEN, THE NETHERLANDS
| | - Albert K Groen
- AMSTERDAM UNIVERSITY MEDICAL CENTERS, AMSTERDAM, THE NETHERLANDS.,UNIVERSITY MEDICAL CENTER GRONINGEN, UNIVERSITY OF GRONINGEN, GRONINGEN, THE NETHERLANDS
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Schonewille M, de Boer JF, Mele L, Wolters H, Bloks VW, Wolters JC, Kuivenhoven JA, Tietge UJF, Brufau G, Groen AK. Statins increase hepatic cholesterol synthesis and stimulate fecal cholesterol elimination in mice. J Lipid Res 2016; 57:1455-64. [PMID: 27313057 DOI: 10.1194/jlr.m067488] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Indexed: 12/19/2022] Open
Abstract
Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis. Statins reduce plasma cholesterol levels, but whether this is actually caused by inhibition of de novo cholesterol synthesis has not been clearly established. Using three different statins, we investigated the effects on cholesterol metabolism in mice in detail. Surprisingly, direct measurement of whole body cholesterol synthesis revealed that cholesterol synthesis was robustly increased in statin-treated mice. Measurement of organ-specific cholesterol synthesis demonstrated that the liver is predominantly responsible for the increase in cholesterol synthesis. Excess synthesized cholesterol did not accumulate in the plasma, as plasma cholesterol decreased. However, statin treatment led to an increase in cholesterol removal via the feces. Interestingly, enhanced cholesterol excretion in response to rosuvastatin and lovastatin treatment was mainly mediated via biliary cholesterol secretion, whereas atorvastatin mainly stimulated cholesterol removal via the transintestinal cholesterol excretion pathway. Moreover, we show that plasma cholesterol precursor levels do not reflect cholesterol synthesis rates during statin treatment in mice. In conclusion, cholesterol synthesis is paradoxically increased upon statin treatment in mice. However, statins potently stimulate the excretion of cholesterol from the body, which sheds new light on possible mechanisms underlying the cholesterol-lowering effects of statins.
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Affiliation(s)
- Marleen Schonewille
- Department of Pediatrics University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jan Freark de Boer
- Department of Pediatrics, Section Molecular Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Laura Mele
- Department of Pediatrics University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Henk Wolters
- Department of Pediatrics University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Vincent W Bloks
- Department of Pediatrics University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Justina C Wolters
- Department of Pediatrics, Section Molecular Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jan A Kuivenhoven
- Department of Pediatrics, Section Molecular Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Uwe J F Tietge
- Department of Pediatrics University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Gemma Brufau
- Department of Pediatrics University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Albert K Groen
- Department of Pediatrics University Medical Center Groningen, University of Groningen, Groningen, The Netherlands Department of Laboratory Medicine, Center for Liver, Digestive and Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands Amsterdam Diabetes Center, Department of Vascular Medicine, Academic Medical Center, The Netherlands
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Temel RE, Brown JM. A new model of reverse cholesterol transport: enTICEing strategies to stimulate intestinal cholesterol excretion. Trends Pharmacol Sci 2015; 36:440-51. [PMID: 25930707 DOI: 10.1016/j.tips.2015.04.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 03/31/2015] [Accepted: 04/06/2015] [Indexed: 01/02/2023]
Abstract
Cardiovascular disease (CVD) remains the largest cause of mortality in most developed countries. Although recent failed clinical trials and Mendelian randomization studies have called into question the high-density lipoprotein (HDL) hypothesis, it remains well accepted that stimulating the process of reverse cholesterol transport (RCT) can prevent or even regress atherosclerosis. The prevailing model for RCT is that cholesterol from the artery wall must be delivered to the liver where it is secreted into bile before leaving the body through fecal excretion. However, many studies have demonstrated that RCT can proceed through a non-biliary pathway known as transintestinal cholesterol excretion (TICE). The goal of this review is to discuss the current state of knowledge of the TICE pathway, with emphasis on points of therapeutic intervention.
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Affiliation(s)
- Ryan E Temel
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536-0509, USA.
| | - J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA.
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Dikkers A, Annema W, de Boer JF, Iqbal J, Hussain MM, Tietge UJF. Differential impact of hepatic deficiency and total body inhibition of MTP on cholesterol metabolism and RCT in mice. J Lipid Res 2014; 55:816-25. [PMID: 24511105 DOI: 10.1194/jlr.m042986] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Because apoB-containing lipoproteins are pro-atherogenic and their secretion by liver and intestine largely depends on microsomal triglyceride transfer protein (MTP) activity, MTP inhibition strategies are actively pursued. How decreasing the secretion of apoB-containing lipoproteins affects intracellular rerouting of cholesterol is unclear. Therefore, the aim of the present study was to determine the effects of reducing either systemic or liver-specific MTP activity on cholesterol metabolism and reverse cholesterol transport (RCT) using a pharmacological MTP inhibitor or a genetic model, respectively. Plasma total cholesterol and triglyceride levels were decreased in both MTP inhibitor-treated and liver-specific MTP knockout (L-Mttp(-/-)) mice (each P < 0.001). With both inhibition approaches, hepatic cholesterol as well as triglyceride content was consistently increased (each P < 0.001), while biliary cholesterol and bile acid secretion remained unchanged. A small but significant decrease in fecal bile acid excretion was observed in inhibitor-treated mice (P < 0.05), whereas fecal neutral sterol excretion was substantially increased by 75% (P < 0.001), conceivably due to decreased intestinal absorption. In contrast, in L-Mttp(-/-) mice both fecal neutral sterol and bile acid excretion remained unchanged. However, while total RCT increased in inhibitor-treated mice (P < 0.01), it surprisingly decreased in L-Mttp(-/-) mice (P < 0.05). These data demonstrate that: i) pharmacological MTP inhibition increases RCT, an effect that might provide additional clinical benefit of MTP inhibitors; and ii) decreasing hepatic MTP decreases RCT, pointing toward a potential contribution of hepatocyte-derived VLDLs to RCT.
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Affiliation(s)
- Arne Dikkers
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Maïga SF, Kalopissis AD, Chabert M. Apolipoprotein A-II is a key regulatory factor of HDL metabolism as appears from studies with transgenic animals and clinical outcomes. Biochimie 2014; 96:56-66. [PMID: 24012775 DOI: 10.1016/j.biochi.2013.08.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/28/2013] [Indexed: 01/26/2023]
Abstract
The structure and metabolism of HDL are linked to their major apolipoproteins (apo) A-I and A-II. HDL metabolism is very dynamic and depends on the constant remodeling by lipases, lipid transfer proteins and receptors. HDL exert several cardioprotective effects, through their antioxidant and antiinflammatory capacities and through the stimulation of reverse cholesterol transport from extrahepatic tissues to the liver for excretion into bile. HDL also serve as plasma reservoir for C and E apolipoproteins, as transport vehicles for a great variety of proteins, and may have more physiological functions than previously recognized. In this review we will develop several aspects of HDL metabolism with emphasis on the structure/function of apo A-I and apo A-II. An important contribution to our understanding of the respective roles of apo A-I and apo A-II comes from studies using transgenic animal models that highlighted the stabilizatory role of apo A-II on HDL through inhibition of their remodeling by lipases. Clinical studies coupled with proteomic analyses revealed the presence of dysfunctional HDL in patients with cardiovascular disease. Beyond HDL cholesterol, a new notion is the functionality of HDL particles. In spite of abundant literature on HDL metabolic properties, a major question remains unanswered: which HDL particle(s) confer(s) protection against cardiovascular risk?
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Le May C, Berger JM, Lespine A, Pillot B, Prieur X, Letessier E, Hussain MM, Collet X, Cariou B, Costet P. Transintestinal cholesterol excretion is an active metabolic process modulated by PCSK9 and statin involving ABCB1. Arterioscler Thromb Vasc Biol 2013; 33:1484-93. [PMID: 23559630 DOI: 10.1161/atvbaha.112.300263] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Transintestinal cholesterol excretion (TICE) is an alternate pathway to hepatobiliary secretion. Our study aimed at identifying molecular mechanisms of TICE. APPROACH AND RESULTS We studied TICE ex vivo in mouse and human intestinal explants, and in vivo after bile diversion and intestinal cannulation in mice. We provide the first evidence that both low-density lipoprotein (LDL) and high-density lipoprotein deliver cholesterol for TICE in human and mouse jejunal explants at the basolateral side. Proprotein convertase subtilisin kexin type 9 (PCSK9)(-/-) mice and intestinal explants show increased LDL-TICE, and acute injection of PCSK9 decreases TICE in vivo, suggesting that PCSK9 is a repressor of TICE. The acute repression was dependent on the LDL receptor (LDLR). Further, TICE was increased when mice were treated with lovastatin. These data point to an important role for LDLR in TICE. However, LDLR(-/-) mice showed increased intestinal LDL uptake, contrary to what is observed in the liver, and tended to have higher TICE. We interpret these data to suggest that there might be at least 2 mechanisms contributing to TICE; 1 involving LDL receptors and other unidentified mechanisms. Acute modulation of LDLR affects TICE, but chronic deficiency is compensated for most likely by the upregulation of the unknown mechanisms. Using mice deficient for apical multidrug active transporter ATP-binding cassette transporter B1 a and b, and its inhibitor, we show that these apical transporters contribute significantly to TICE. CONCLUSIONS TICE is operative in human jejunal explants. It is a metabolically active process that can be acutely regulated, inversely related to cholesterolemia, and pharmacologically activated by statins.
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Affiliation(s)
- Cédric Le May
- INSERM, UMR 1087, CNRS UMR 6291, Nantes F-44000, France
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