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Li Y, Rao Y, Zhu H, Jiang B, Zhu M. USP16 Regulates the Stability and Function of LDL receptor by Deubiquitination. Int Heart J 2020; 61:1034-1040. [PMID: 32999190 DOI: 10.1536/ihj.20-043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Low-density lipoprotein (LDL) particles are known to be atherogenic agents in coronary artery diseases. They adjust to other electronegative forms and can be the subject for the enhancement of inflammatory events in vessel subendothelial spaces. The LDL uptake is related to the membrane scavenger receptors, including LDL receptor (LDLR). The LDLR expression is closely associated with LDL uptake and occurrence of diseases, such as atherosclerotic cardiovascular diseases. Our findings identified USP16 as a novel regulator of LDLR due to its ability to prevent ubiquitylation-dependent LDLR degradation, further promoting the uptake of LDL. The enhancement of USP16-mediated deubiquitination andthe suppressive degradation of the LDLR cause the presentation of a potential strategy to increase LDL cholesterol clearance.
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Affiliation(s)
- Yongsheng Li
- Department of Cardiovascular Internal Medicine, The Fifth Hospital of Xiamen
| | - Yanbiao Rao
- Department of Cardiovascular Internal Medicine, The Fifth Hospital of Xiamen
| | - Hongtao Zhu
- Department of Cardiovascular Internal Medicine, The Fifth Hospital of Xiamen
| | - Bingyuan Jiang
- Department of Cardiovascular Internal Medicine, The Fifth Hospital of Xiamen
| | - Maoshu Zhu
- Central Laboratory, The Fifth Hospital of Xiamen
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Ripollés Piquer B, Nazih H, Bourreille A, Segain JP, Huvelin JM, Galmiche JP, Bard JM. Altered lipid, apolipoprotein, and lipoprotein profiles in inflammatory bowel disease: consequences on the cholesterol efflux capacity of serum using Fu5AH cell system. Metabolism 2006; 55:980-8. [PMID: 16784973 DOI: 10.1016/j.metabol.2006.03.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Accepted: 03/02/2006] [Indexed: 01/06/2023]
Abstract
Epidemiological data suggest a link between chronic inflammation condition and atherosclerosis. Infection and inflammation can also impair lipoprotein metabolism and produce a wide variety of changes in plasma concentrations of lipids and lipoproteins. Twenty-one patients with inflammatory bowel diseases (IBDs) and 28 healthy subjects were recruited. Serum concentrations of lipids, lipoproteins, apolipoproteins, leptin, ghrelin, and inflammation markers (C-reactive protein and serum amyloid A) were measured, and subjects' lipoproteins were characterized. The ability of patients with serum IBD to efflux free cell cholesterol was measured. Serum cholesterol, high-density lipoprotein cholesterol, apolipoprotein (apo) A-I, apoC-II, apoC-III bound to apoB, phospholipid, and phospholipids not bound to apoB levels were significantly lower, whereas serum triglyceride, serum amyloid A, and C-reactive protein levels were significantly higher in patients with active IBD. Apolipoprotein A-I immunoreactivity (pre-beta small particles and small alpha-high-density lipoprotein particles) is decreased in patients with IBD. In contrast, apoE immunoreactivity (slow/small apoE containing lipoprotein particles [LpE particle]) increased in these patients. The efflux capacity of serum from patients with IBD using [(3)H]-cholesterol-labeled Fu5AH cells was reduced (P < .005). Our results demonstrate that, in subjects with active IBD, inflammation leads to alterations in lipid, apolipoprotein, and lipoprotein profiles and reduced cholesterol efflux. These changes are similar to those proposed to promote atherogenesis and may contribute to the development of cardiovascular events.
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Affiliation(s)
- Blanca Ripollés Piquer
- Laboratoire de Biochimie Générale et Appliquée, UFR de Pharmacie, Université de Nantes, 44035 Nantes, France
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Zimetti F, Weibel GK, Duong M, Rothblat GH. Measurement of cholesterol bidirectional flux between cells and lipoproteins. J Lipid Res 2006; 47:605-13. [PMID: 16327021 DOI: 10.1194/jlr.m500466-jlr200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We developed an assay that quantitates bidirectional cholesterol flux between cells and lipoproteins. Incubating Fu5AH cells with increasing concentrations of human serum resulted in increased influx and efflux; however, influx was 2- to 3-fold greater at all serum concentrations. With apolipoprotein B (apoB)-depleted serum, the ratio of influx to efflux (I/E) was close to 1, indicating cholesterol exchange. The apoB fraction of serum induced influx and little efflux, with I/E > 1. Using block lipid transport-1 to block scavenger receptor class B type I (SR-BI)-mediated flux with different acceptors, we determined that 50% to 70% of efflux was via SR-BI. With HDL, 90% of influx was via SR-BI, whereas with LDL or serum, 20% of influx was SR-BI-mediated. Cholesterol-enriched hepatoma cells produced increased efflux without a change in influx, resulting in reduced I/E. The assay was applied to cholesterol-normal and -enriched mouse peritoneal macrophages exposed to serum or LDL. The enrichment enhanced efflux without shifts in influx. With cholesterol-enriched macrophages, HDL efflux was enhanced and influx was greatly reduced. With all lipoproteins, cholesterol enrichment of murine peritoneal macrophages led to a reduced I/E. We conclude that this assay can simultaneously and accurately quantitate cholesterol bidirectional flux and can be applied to a variety of cells exposed to isolated lipoproteins or serum.
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Affiliation(s)
- Francesca Zimetti
- Gastrointestinal and Nutrition Division, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
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Lee CS, Han JH, Lee SM, Hwang JS, Kang SW, Lee BH, Kim HR. Wax moth, Galleria mellonella fat body receptor for high-density lipophorin (HDLp). ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2003; 54:14-24. [PMID: 12942512 DOI: 10.1002/arch.10095] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To identify and characterize the HDLp (high-density lipophorin) receptor from Galleria mellonella (LpRGm), we used techniques of ligand blotting. This method was, to our knowledge, first used to characterize the lipophorin receptor (LpR) in insects. LpRGm had an approximate molecular weight of 97 kDa under non-reducing conditions and bound the HDLp specifically. The time-course of lipophorin binding to their receptor protein was rapid. The binding of lipophorins to their receptors was saturable with a Kd of 34.33+/-4.67 microg/ml. Although Ca2+ was essentially required in the binding of HDLp to their receptors, interestingly increasing concentration of Ca2+ has shown to have a slight inhibitory effect. EDTA was used here as Ca2+ chelating reagent, because Mg2+ in the binding buffer did not affect the binding of HDLp to their receptors, and inhibited the binding of HDLp and LpRGm absolutely. Suramin (polysulfated polycyclic hydrocarbon), known to inhibit the binding of lipoproteins to their receptors, effectively abolished the binding of HDLp to their receptors. LpRGm showed the stage specific binding activity especially in day 1-3 last instar larval, prepupal, and day 1-3 adult stages.
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Affiliation(s)
- Chang Seok Lee
- Laboratory of Animal Macromolecules, Physiology and Biochemistry, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea
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Fournier N, Atger V, Paul JP, de la Llera Moya M, Rothblat G, Moatti N. Fractional efflux and net change in cellular cholesterol content mediated by sera from mice expressing both human apolipoprotein AI and human lecithin:cholesterol acyltransferase genes. Atherosclerosis 1999; 147:227-35. [PMID: 10559507 DOI: 10.1016/s0021-9150(99)00188-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Human lecithin:cholesterol acyltransferase (LCAT) is a key enzyme in the metabolism of cholesterol and is postulated to participate in the physiological process called reverse cholesterol transport. We have used transgenic mice (Tgm) expressing either both human apolipoprotein AI (apo AI) and human LCAT genes or only the human apo AI gene (HuAILCAT or HuAI Tgm, respectively) to assess the consequences of LCAT overexpression on serum lipid and lipoprotein profiles and on the ability of each serum to promote bidirectional flux of cholesterol between serum and Fu5AH hepatoma cells. Mean serum LCAT activity of HuAILCAT Tgm was 2-fold increased compared to the HuAI group (48+/-9 vs. 24+/-5 nmol/ml per h, P<0.01 for HuAILCAT and HuAI Tgm, respectively) and the cholesterol esterification rates were not significantly different between the two groups of animals (66+/-11 vs. 74+/-18 nmol/ml per h for HuAILCAT and HuAI Tgm, respectively). HuAILCAT Tgm exhibited higher total cholesterol serum values (2.3-fold) due to an increase in both HDL-cholesterol (1. 9-fold) and non-HDL-cholesterol (3-fold). The HDL particles from HuAILCAT Tgm were relatively phospholipid depleted and cholesterol enriched compared to HuAI mice. When cells were incubated for six hours with the mouse serum, the fractional efflux of radiolabeled cholesterol was slightly increased with the HuAILCAT Tgm (1.2-fold) but the increase in intracellular cholesterol content was also 2-fold higher than with the HuAI Tgm. Fu5AH can be viewed as a model for the evaluation of bidirectional flux of cholesterol in SR-BI-rich cells. In this model LCAT overexpression in mice, by increasing both HDL and non-HDL-cholesterol, mostly enhances the uptake of cholesterol by the cells, which would be of benefit for the last step of reverse cholesterol transport in hepatocytes.
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Affiliation(s)
- N Fournier
- Laboratoire de Biochimie Appliquée, Faculté des Sciences Pharmaceutiques et Biologiques, Châtenay-Malabry, France.
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Huang Y, Ghosh MJ, Lopes-Virella MF. Transcriptional and post-transcriptional regulation of LDL receptor gene expression in PMA-treated THP-1 cells by LDL-containing immune complexes. J Lipid Res 1997. [DOI: 10.1016/s0022-2275(20)37280-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Chang S, Borensztajn J. Uptake of chylomicron remnants and hepatic lipase-treated chylomicrons by a non-transformed murine hepatocyte cell line in culture. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1256:81-7. [PMID: 7742359 DOI: 10.1016/0005-2760(95)00008-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
AML 12 is a recently established differentiated, non-transformed hepatocyte cell line derived from mice transgenic for transforming growth factor alpha (Wu et al. (1994) Proc. Natl. Acad. Sci. 91, 674-678). The ability of these cells to take up [3H]cholesterol-labeled in vivo-generated chylomicron remnants, as well as [3H]cholesterol-labeled chylomicrons treated with hepatic lipase in vitro was investigated. Both types of lipoprotein particles were taken up by the AML hepatocytes at a much faster rate than intact chylomicrons, and in a saturable and specific manner. Chylomicrons treated with hepatic lipase in vitro competed with in vivo-generated chylomicron remnants for uptake by the AML hepatocytes, and the uptake of both types of lipoproteins was inhibited by lactoferrin, suggesting that they share the same process of cellular recognition and uptake. It is suggested that hepatic lipase-treated chylomicrons may be valuable in studies aimed at gaining a better understanding of the processes involved in the hepatic recognition and uptake of chylomicron remnants. AML hepatocytes, which can be maintained as replicating, untransformed, and differentiated under standard culture conditions, may be useful and practical for such studies.
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Affiliation(s)
- S Chang
- Department of Pathology, Northwestern University Medical School, Chicago, IL 60611, USA
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Mazière JC, Mazière C, Emami S, Noel B, Poumay Y, Ronveaux MF, Chastre E, Porte H, Barbu V, Biade S. Processing and characterization of the low density lipoprotein receptor in the human colonic carcinoma cell subclone HT29-18: a potential pathway for delivering therapeutic drugs and genes. Biosci Rep 1992; 12:483-94. [PMID: 1298438 DOI: 10.1007/bf01122036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Low density lipoprotein (LDL) processing has been investigated in the subcloned human colonic carcinoma cell line HT29-18. LDL binding at 4 degrees C was a saturable process in relation to time and LDL concentration. The Kd for LDL binding was 11 micrograms/ml. ApoE-free HDL3 or acetylated LDL did not significantly compete with 125I-LDL binding, up to 500 micrograms/ml. 125I-LDL binding was decreased by 70% in HT29-18 cells preincubated for 24 hours in culture medium containing 100 micrograms/ml unlabelled LDL. Ligand blotting studies performed on HT29-18 homogenates using colloidal gold labelled LDL indicated the presence of one autoradiographic band corresponding to an apparent molecular weight of 130 kDa, which is consistent with the previously reported molecular weight of the LDL receptor in human fibroblasts. At 37 degrees C, 125I-LDL was actively internalized by HT29-18 cells and lysosomal degradation occurred as demonstrated by the inhibitory effect of chloroquine. LDL uptake and degradation by HT29-18 cells also resulted in a marked decrease in endogenous sterol synthesis. These data demonstrate that the HT29-18 human cancerous intestinal cells are able to specifically bind and internalize LDL, and that LDL processing results in down-regulation of sterol biosynthesis. Thus, intestinal epithelial cells possess specific LDL receptors that can be exploited to accomplish drug delivery and gene transfer via the receptor-mediated endocytosis pathway.
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Affiliation(s)
- J C Mazière
- Laboratoire de Biochimie, INSERM U312, Faculté de Médecine Saint-Antoine, Paris, France
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Regulation of the hepatic removal of chylomicron remnants and beta-very low density lipoproteins in the rat. J Lipid Res 1992. [DOI: 10.1016/s0022-2275(20)41532-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Friedman G, Gavish D, Vogel T, Eisenberg S. Cellular metabolism of human plasma intermediate-density lipoprotein (IDL). BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1044:118-26. [PMID: 2340301 DOI: 10.1016/0005-2760(90)90226-n] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The cellular metabolism of human plasma intermediate-density lipoprotein (IDL) was investigated in cultured human skin fibroblasts and hepG-2 cell in the absence and presence of exogenous recombinant or plasmatic apo E-3. IDL (d 1.006-1.019 g/ml) and LDL (d 1.019-1.063 g/ml) were prepared by centrifugation from the plasma of apo E-3/3 or 4/3 normolipidemic human subjects. Without added apo E-3, IDL binding and cell association are similar or slightly reduced while their degradation is one third to one half. This results in degradation to binding ratios for IDL that are half those for LDL. Exogenous apo E-3 enhances binding, association and degradation of IDL by 50-150%, but the degradation to binding ratio remains low. Exogenous apo E-3 also increased the ability of IDL but not LDL, to down-regulate the incorporation of [14C]acetate to sterol by the cells. The optimal concentration of apo E-3 is 4 micrograms protein/10 micrograms IDL protein and at that concentration appreciable amounts of the apo E are found associated with the lipoprotein. Apo E-2 has no effect on the cellular metabolism of IDL and apo E-3 is not effective in receptor-negative human fibroblasts. Monoclonal antibodies that block apo E binding to B,E (LDL) receptor (1D7) abolish the cellular metabolism of IDL while antibodies against B-100 (4G3) are ineffective. In competitive binding experiments, IDL is slightly more effective than LDL in displacing 125I-LDL from receptors in hepG-2 cells and appreciably more effective than LDL when tested against 125I-IDL. Apo E-3 increases the capacity of IDL to compete with either 125I-LDL or 125I-IDL. Addition of apo E-3 also increases the binding affinity of IDL to hepG-2 receptors, with Kd values of 2.50, 0.93 micrograms protein/ml, respectively. The study demonstrates the essential role that functional apo E molecules play in the interaction of human IDL with cellular receptors. Yet, in spite of presence of apo E in IDL (2-3 molecules/particle) and enrichment of IDL with apo E-3 (to 4-5 molecules/particle) the proteolytic degradation of the lipoprotein by specific cellular receptor is similar to LDL.
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Affiliation(s)
- G Friedman
- Department of Medicine B, Hadassah University Hospital, Jerusalem, Israel
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