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Santos MJS, Canuto KM, de Aquino CC, Martins CS, Brito GAC, Pessoa TMRP, Bertolini LR, de Sá Carneiro I, Pinto DV, Nascimento JCR, da Silva BB, Valença JT, Guedes MIF, Owen JS, Oriá RB. A Brazilian regional basic diet-induced chronic malnutrition drives liver inflammation with higher ApoA-I activity in C57BL6J mice. ACTA ACUST UNITED AC 2020; 53:e9031. [PMID: 32401929 PMCID: PMC7228546 DOI: 10.1590/1414-431x20209031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 03/23/2020] [Indexed: 01/10/2023]
Abstract
Malnutrition is still considered endemic in many developing countries. Malnutrition-enteric infections may cause lasting deleterious effects on lipid metabolism, especially in children living in poor settings. The regional basic diet (RBD), produced to mimic the Brazilian northeastern dietary characteristics (rich in carbohydrate and low in protein) has been used in experimental malnutrition models, but few studies have explored the effect of chronic RBD on liver function, a central organ involved in cholesterol metabolism. This study aimed to investigate whether RBD leads to liver inflammatory changes and altered reverse cholesterol metabolism in C57BL6/J mice compared to the control group, receiving a standard chow diet. To evaluate liver inflammation, ionized calcium-binding adapter protein-1 (IBA-1) positive cell counting, interleukin (IL)-1β immunohistochemistry, and tumor necrosis factor (TNF)-α and IL-10 transcription levels were analyzed. In addition, we assessed reverse cholesterol transport by measuring liver apolipoprotein (Apo)E, ApoA-I, and lecithin-cholesterol acyltransferase (LCAT) by RT-PCR. Furthermore, serum alanine aminotransferase (ALT) was measured to assess liver function. RBD markedly impaired body weight gain compared with the control group (P<0.05). Higher hepatic TNF-α (P<0.0001) and IL-10 (P=0.001) mRNA levels were found in RBD-challenged mice, although without detectable non-alcoholic fatty liver disease. Marked IBA-1 immunolabeling and increased number of positive-IBA-1 cells were found in the undernourished group. No statistical difference in serum ALT was found. There was also a significant increase in ApoA mRNA expression in the undernourished group, but not ApoE and LCAT, compared with the control. Altogether our findings suggested that chronic RBD-induced malnutrition leads to liver inflammation with increased ApoA-I activity.
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Affiliation(s)
- M J S Santos
- Laboratório da Biologia da Cicatrização Tecidual, Ontogenia e Nutrição de Tecidos, Departamento de Morfologia e Instituto de Biomedicina, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
| | - K M Canuto
- Laboratório da Biologia da Cicatrização Tecidual, Ontogenia e Nutrição de Tecidos, Departamento de Morfologia e Instituto de Biomedicina, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
| | - C C de Aquino
- Laboratório da Biologia da Cicatrização Tecidual, Ontogenia e Nutrição de Tecidos, Departamento de Morfologia e Instituto de Biomedicina, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
| | - C S Martins
- Núcleo de Microscopia e Processagem de Imagens, Departamento de Morfologia e Instituto de Biomedicina, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
| | - G A C Brito
- Núcleo de Microscopia e Processagem de Imagens, Departamento de Morfologia e Instituto de Biomedicina, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
| | - T M R P Pessoa
- Ciências da Saúde, Universidade de Fortaleza, Fortaleza, CE, Brasil
| | - L R Bertolini
- Ciências da Saúde, Universidade de Fortaleza, Fortaleza, CE, Brasil
| | - I de Sá Carneiro
- Ciências da Saúde, Universidade de Fortaleza, Fortaleza, CE, Brasil
| | - D V Pinto
- Laboratório da Biologia da Cicatrização Tecidual, Ontogenia e Nutrição de Tecidos, Departamento de Morfologia e Instituto de Biomedicina, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
| | - J C R Nascimento
- Laboratório da Biologia da Cicatrização Tecidual, Ontogenia e Nutrição de Tecidos, Departamento de Morfologia e Instituto de Biomedicina, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
| | - B B da Silva
- Laboratório de Biologia e Biotecnologia Molecular, Universidade Estadual do Ceará, Fortaleza, CE, Brasil
| | - J T Valença
- Departamento de Patologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
| | - M I F Guedes
- Laboratório de Biologia e Biotecnologia Molecular, Universidade Estadual do Ceará, Fortaleza, CE, Brasil
| | - J S Owen
- Division of Medicine, Royal Free Campus, University College London Medical School, Hampstead, London, United Kingdom
| | - R B Oriá
- Laboratório da Biologia da Cicatrização Tecidual, Ontogenia e Nutrição de Tecidos, Departamento de Morfologia e Instituto de Biomedicina, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
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Abstract
SummaryPlatelet aggregation, platelet lipid composition and plasma lipoprotein concentrations were measured each week in a group of seventeen alcoholics, without overt liver disease, for one month, following acute, total alcohol withdrawal. The platelets were initially hypoaggregable but, within 1-2 weeks of cessation of drinking, they became hyperaggregable and then gradually returned towards normal values. Hyperaggregability could not be explained by increases in either the cholesterol or the arachidonic acid content of the platelets. Plasma very-low-density lipoprotein cholesterol levels remained high throughout the study, but the initially raised levels of high-density lipoprotein (HDL) cholesterol fell by 26%. Low-density lipoprotein (LDL) cholesterol concentration rose by 10% after two weeks of withdrawal but then returned to about the starting level. The resulting changes in the plasma LDL-cholesterol: HDL-cholesterol ratio, which had increased by more than 50% after two weeks of abstinence, essentially paralleled the time course of enhanced platelet reactivity in all but four of the alcoholics. These findings suggest that alterations in plasma lipoprotein concentrations during acute alcohol withdrawal may be a contributory factor to the haemostatic disorders present in such patients.
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Affiliation(s)
- K Desai
- The Departments of Haematology and Medicine, Royal Free Hospital School of Medicine, London, and The Regional Alcoholism and Drug Dependence Unit, St. Bernard’s Hospital, London, UK
| | - J S Owen
- The Departments of Haematology and Medicine, Royal Free Hospital School of Medicine, London, and The Regional Alcoholism and Drug Dependence Unit, St. Bernard’s Hospital, London, UK
| | - D T Wilson
- The Departments of Haematology and Medicine, Royal Free Hospital School of Medicine, London, and The Regional Alcoholism and Drug Dependence Unit, St. Bernard’s Hospital, London, UK
| | - R A Hutton
- The Departments of Haematology and Medicine, Royal Free Hospital School of Medicine, London, and The Regional Alcoholism and Drug Dependence Unit, St. Bernard’s Hospital, London, UK
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Hendricks MP, Campos MP, Cleveland GT, Jen-La Plante I, Owen JS. A tunable library of substituted thiourea precursors to metal sulfide nanocrystals. Science 2015; 348:1226-30. [DOI: 10.1126/science.aaa2951] [Citation(s) in RCA: 271] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Small A, McLean D, Keates H, Owen JS, Ralph J. Preliminary investigations into the use of microwave energy for reversible stunning of sheep. Anim Welf 2013. [DOI: 10.7120/09627286.22.2.291] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
Tigecycline, a novel glycylcycline, possesses broad-spectrum antimicrobial activity. A structural population pharmacokinetic model for tigecycline was developed based on data pooled from 5 phase I studies. Intravenous tigecycline was administered as single (12.5-300 mg) or multiple (25-100 mg) doses every 12 hours for up to 10 days. Three-compartment models with zero-order input and first-order elimination separately described the single- or multiple-dose full-profile data. Additional models were evaluated using a subset of the phase I data mimicking the phase II/III trial sparse-sampling scheme and dosage. A 2-compartment model best described the reduced phase I data following single or multiple doses and provided reliably accurate estimates of tigecycline AUC(0-12). This modeling supported phase II/III population pharmacokinetic model development to further determine individual patient tigecycline exposures for safety and efficacy analyses.
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Affiliation(s)
- S A Van Wart
- Cognigen Corporation, 395 Youngs Road, Buffalo, NY 14221, USA.
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Owen JS, Gillett MPT. Lecithin: Cholesterol Acyltransferase Deficiency Associated with Hepatic Schistosomiasis Mansoni. Scandinavian Journal of Clinical and Laboratory Investigation 2011. [DOI: 10.1080/00365517809104925] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Pai AB, Nielsen JC, Kausz A, Miller P, Owen JS. Plasma pharmacokinetics of two consecutive doses of ferumoxytol in healthy subjects. Clin Pharmacol Ther 2010; 88:237-42. [PMID: 20592725 DOI: 10.1038/clpt.2010.80] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Intravenous (IV) iron is used to treat iron-deficiency anemia in patients with chronic kidney disease (CKD). Ferumoxytol is a novel iron formulation administered rapidly as two IV boluses of 510 mg each. In this placebo-controlled, double-blind, parallel-group study, 58 healthy volunteers received ferumoxytol in two 510 mg doses administered 24 h apart. Population pharmacokinetics (PK) analysis was conducted, and a two-compartment open model with zero-order input and Michaelis-Menten elimination was found to best describe the data. The population mean estimates for volume of distribution of the central compartment (V(1)), maximal elimination rate (V(max)), and ferumoxytol concentration at which rate of metabolism would be one-half of V(max) (K(m)) were 2.71 l, 14.3 mg/h, and 77.5 mg/l, respectively. When the effect of body weight on V(1) was added in the analysis, interindividual variability was found to be reduced. A noncompartmental analysis of two simulated 510-mg ferumoxytol doses was also performed to provide clinically interpretable data on half life and exposure. Ferumoxytol given as two consecutive 510-mg doses was well tolerated.
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Affiliation(s)
- A B Pai
- Albany Nephrology Pharmacy Group, Albany College of Pharmacy and Health Sciences, Albany, New York, USA.
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Hassall DG, Desai K, Owen JS, Bruckdorfer KR. Detection of a Protein in Human Platelet Membranes which Binds Low-density Lipoproteins. Platelets 2009; 1:29-35. [DOI: 10.3109/09537109009009193] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Fetterly GJ, Owen JS, Stuyckens K, Passarell JA, Zannikos P, Matos AS, Izquierdo MA, Perez-Ruixo JJ. Mechanism-based PKPD model for hepatoprotective effect of dexamethasone on transient transaminitis after trabectedin (ET- 743) treatment. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.2545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
2545 Background: Reversible transient elevations in transaminases have been observed after trabectedin (T) administration, despite no alteration in plasma PK. A PKPD model was developed to evaluate the time course of ALT elevation, tolerance development, and covariate effects following different dosing schedules in cancer subjects. Methods: T was administered to 711 subjects as monotherapy (dose range: 0.024 - 1.8 mg/m2) as 1-, 3-, or 24-hr infusions every 21 days; 1- or 3-hr infusions on days 1, 8, and 15 every 28 days; or 1-hr infusions daily for 5 consecutive days every 21 days. Population PKPD modeling was performed with covariate evaluation [dexamethasone use (469/711 pt), ECOG PS scores (89.7% pts = 1), and BW (36–122 kg)] on PD parameters, followed by model validation. Simulations assessed the influence of dosing regimen and selected covariates on the time course of ALT and the effectiveness of the dose reduction strategy. Results: A precursor-dependent PKPD model described the temporal relationship between ALT elevation and T concentrations, where the transfer process of ALT from hepatocytes to plasma is stimulated by trabectedin plasma concentration. Overall, 66% of subjects had transaminitis. Mean predicted (%SEM) baseline ALT (ALTo) and T1/2 in plasma were 33 (5.5) U/L and 1.4 days, respectively. The magnitude of the T stimulation on the ALT transfer rate from hepatocytes to plasma was 11.2% per 100 pg/mL of trabectedin plasma concentration. Dexamethasone decreased the rate of T-induced ALT release from hepatocyte by 63% (p<0.001). Model validation results showed good concordance with the observed incidence of grade 3/4 toxicity. Simulations showed that severity of ALT elevation was dose- and schedule-dependent. The dose reduction strategy decreased the incidence of grade =3 toxicity by 13% and 39% following 2 and 4 cycles of therapy, respectively. Conclusions: A PKPD model quantifying the hepatoprotective effect of dexamethasone on transient and reversible transaminitis after T treatment has been developed. The model predicts that co-administration of dexamethasone and the suggested dose reduction strategy will enhance the safe use of T in the clinic. No significant financial relationships to disclose.
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Affiliation(s)
- G. J. Fetterly
- Cognigen Corporation, Buffalo, NY; Johnson and Johnson Pharmaceutical RD, Beerse, Belgium; Pharmamar, Madrid, Spain
| | - J. S. Owen
- Cognigen Corporation, Buffalo, NY; Johnson and Johnson Pharmaceutical RD, Beerse, Belgium; Pharmamar, Madrid, Spain
| | - K. Stuyckens
- Cognigen Corporation, Buffalo, NY; Johnson and Johnson Pharmaceutical RD, Beerse, Belgium; Pharmamar, Madrid, Spain
| | - J. A. Passarell
- Cognigen Corporation, Buffalo, NY; Johnson and Johnson Pharmaceutical RD, Beerse, Belgium; Pharmamar, Madrid, Spain
| | - P. Zannikos
- Cognigen Corporation, Buffalo, NY; Johnson and Johnson Pharmaceutical RD, Beerse, Belgium; Pharmamar, Madrid, Spain
| | - A. S. Matos
- Cognigen Corporation, Buffalo, NY; Johnson and Johnson Pharmaceutical RD, Beerse, Belgium; Pharmamar, Madrid, Spain
| | - M. A. Izquierdo
- Cognigen Corporation, Buffalo, NY; Johnson and Johnson Pharmaceutical RD, Beerse, Belgium; Pharmamar, Madrid, Spain
| | - J. J. Perez-Ruixo
- Cognigen Corporation, Buffalo, NY; Johnson and Johnson Pharmaceutical RD, Beerse, Belgium; Pharmamar, Madrid, Spain
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Van Wart SA, Owen JS, Ludwig EA, Meagher AK, Korth-Bradley JM, Cirincione BB. Population pharmacokinetics of tigecycline in patients with complicated intra-abdominal or skin and skin structure infections. Antimicrob Agents Chemother 2006; 50:3701-7. [PMID: 16940069 PMCID: PMC1635236 DOI: 10.1128/aac.01636-05] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tigecycline, a first-in-class expanded glycylcycline antimicrobial agent, has demonstrated efficacy in the treatment of complicated skin and skin structure infections (cSSSI) and complicated intra-abdominal (cIAI) infections. A population pharmacokinetic (PK) model for tigecycline was developed for patients with cSSSI or cIAI enrolled in two phase 2 clinical trials, and the influence of selected demographic factors and clinical laboratory measures was investigated. Tigecycline was administered as an intravenous loading dose followed by a 0.5- or 1-h infusion every 12 h for up to 14 days. Blood samples were collected the day before or the day of hospital discharge for the determination of serum tigecycline concentrations. Patient covariates were evaluated using stepwise forward (alpha = 0.05) and backward (alpha = 0.001) procedures. The predictive performance of the model was assessed separately using pooled data from either two phase 3 studies for patients with cSSSI or two phase 3 studies for patients with cIAI. A two-compartment model with zero-order input and first-order elimination adequately described the steady-state tigecycline concentration-time data. Tigecycline clearance was shown to increase with increasing weight, increasing creatinine clearance, and male gender (P < 0.001). The final model provided a relatively unbiased fit to each data set. Individual predicted values of the area under the concentration-time curve from 0 to 12 h (AUC(0-12)) were generally unbiased (median prediction error, -1.60% to -3.78%) and were similarly precise (median absolute prediction error, <4%) when compared across data sets. The population PK model provided the basis to obtain individual estimates of steady-state AUC(0-12) in later exposure-response analyses of tigecycline safety and efficacy in patients with cSSSI or cIAI.
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Affiliation(s)
- S A Van Wart
- Cognigen Corporation, 395 Youngs Road, Buffalo, NY 14221, USA.
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Facundo HTF, Brandt CT, Owen JS, Lima VLM. Elevated levels of erythrocyte-conjugated dienes indicate increased lipid peroxidation in schistosomiasis mansoni patients. Braz J Med Biol Res 2004; 37:957-62. [PMID: 15264001 DOI: 10.1590/s0100-879x2004000700003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Schistosoma mansoni causes liver disease by inducing granulomatous inflammation. This favors formation of reactive oxygen species, including superoxide ions, hydrogen peroxide and hydroxyl radicals all of which may induce lipid peroxidation. We have evaluated lipid peroxidation in 18 patients with hepatosplenic schistosomiasis mansoni previously treated with oxamniquine followed by splenectomy, ligature of the left gastric vein and auto-implantation of spleen tissue, by measuring levels of erythrocyte-conjugated dienes and plasma malondialdehyde (MDA). Age-matched, healthy individuals (N = 18) formed the control group. Erythrocyte-conjugated dienes were extracted with dichloromethane/methanol and quantified by UV spectrophotometry, while plasma MDA was measured by reaction with thiobarbituric acid. Patient erythrocytes contained two times more conjugated dienes than control cells (584.5 +/- 67.8 vs 271.7 +/- 20.1 micromol/l, P < 0.001), whereas the increase in plasma MDA concentration (about 10%) was not statistically significant. These elevated conjugated dienes in patients infected by S. mansoni suggest increased lipid peroxidation in cell membranes, although this was not evident when a common marker of oxidative stress, plasma MDA, was measured. Nevertheless, these two markers of lipid peroxidation, circulating MDA and erythrocyte-conjugated dienes, correlated significantly in both patient (r = 0.62; P < 0.01) and control (r = 0.57; P < 0.05) groups. Our data show that patients with schistosomiasis have abnormal lipid peroxidation, with elevated erythrocyte-conjugated dienes implying dysfunctional cell membranes, and also imply that this may be attenuated by the redox capacity of antioxidant agents, which prevent accumulation of plasma MDA.
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Affiliation(s)
- H T F Facundo
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Recife, PE, Brazil
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Harris JD, Schepelmann S, Athanasopoulos T, Graham IR, Stannard AK, Mohri Z, Hill V, Hassall DG, Owen JS, Dickson G. Inhibition of atherosclerosis in apolipoprotein-E-deficient mice following muscle transduction with adeno-associated virus vectors encoding human apolipoprotein-E. Gene Ther 2002; 9:21-9. [PMID: 11850719 DOI: 10.1038/sj.gt.3301615] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2001] [Accepted: 10/29/2001] [Indexed: 11/08/2022]
Abstract
Apolipoprotein E (apoE) is a multifunctional plasma glycoprotein involved in lipoprotein metabolism and a range of cell signalling phenomena. ApoE-deficient (apoE(-/-)) mice exhibit severe hypercholesterolaemia and are an excellent model of human atherosclerosis. ApoE somatic gene transfer and bone marrow transplantation in apoE(-/-) mice results in reversal of hypercholesterolaemia, inhibition of atherogenesis and regression of atherosclerotic plaque density. Replication defective adeno-associated virus vectors (rAAVs) are an attractive system currently in clinical trial for muscle-based heterologous gene therapy to express secreted recombinant plasma proteins. Here we have applied rAAV transduction of skeletal muscle to express wild-type (epsilon3) and a defective receptor-binding mutant (epsilon2) human apoE transgene in apoE(-/-) mice. In treated animals, apoE mRNA was present in transduced muscles and, although plasma levels of recombinant apoE fell below the detection levels of our ELISA (ie <10 ng/ml), circulating antibodies to human apoE and rAAV were induced. Up to 3 months after a single administration of rAAV/apoE3, a significant reduction in atherosclerotic plaque density in aortas of treated animals was observed (approximately 30%), indicating that low-level rAAV-mediated apoE3 expression from skeletal muscle can retard atherosclerotic progression in this well-defined genetic model.
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Affiliation(s)
- J D Harris
- Centre for Biomedical Research, School of Biological Sciences, Royal Holloway, University of London, Egham, UK
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Stannard AK, Riddell DR, Sacre SM, Tagalakis AD, Langer C, von Eckardstein A, Cullen P, Athanasopoulos T, Dickson G, Owen JS. Cell-derived apolipoprotein E (ApoE) particles inhibit vascular cell adhesion molecule-1 (VCAM-1) expression in human endothelial cells. J Biol Chem 2001; 276:46011-6. [PMID: 11590165 DOI: 10.1074/jbc.m104812200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Sub-endothelial infiltration of monocytes occurs early in atherogenesis and is facilitated by cell adhesion molecules that are up-regulated on activated endothelium. Apolipoprotein E (apoE) helps protect against atherosclerosis, in part, because apoE particles secreted by macrophages have local beneficial effects at lesion sites. Here, we hypothesize that such protection includes anti-inflammatory actions and investigate whether cell-derived apoE can inhibit tumor necrosis factor-alpha-mediated up-regulation of vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs). Two models were used to mimic endothelial exposure to macrophage-derived apoE. In the first, HUVECs were transiently transfected to secrete apoE; VCAM-1 induction inversely correlated with secretion of apoE into the media (r = -0.76, p < 0.001). In the second, incubation of HUVECs with media from recombinant Chinese hamster ovary (CHO) cells expressing apoE (CHO(apoE)) also reduced VCAM-1 in a dose-dependent manner (r = -0.70, p < 0.001). Characterization of CHO(apoE) cell-derived apoE revealed several similarities to apoE particles secreted by human blood monocyte-derived macrophages. The suppression of endothelial activation by apoE most likely occurs via stimulation of endothelial nitric oxide synthase; apoE increased levels of intracellular nitric oxide and its surrogate marker, cyclic guanosine monophosphate, while the nitric oxide synthase inhibitor, ethyl-isothiourea, blocked its effect. We propose that apoE secreted locally at lesion sites by macrophages may be anti-inflammatory by stimulating endothelium to release NO and suppress VCAM-1 expression.
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Affiliation(s)
- A K Stannard
- Department of Medicine, Royal Free and University College Medical School, London NW3 2PF, United Kingdom
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Riddell DR, Sun XM, Stannard AK, Soutar AK, Owen JS. Localization of apolipoprotein E receptor 2 to caveolae in the plasma membrane. J Lipid Res 2001; 42:998-1002. [PMID: 11369809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023] Open
Abstract
The LDL receptor (LDL-R) promotes the specific endocytosis and lysosomal delivery of extracellular lipoprotein ligands via clathrin-coated pits. It was widely assumed that other closely related members of the LDL-R gene family would have similar functions, but recent experimental evidence has revealed that one such protein, apolipoprotein E receptor 2 (apoER2), has a critical role as an "outside-in" signal transducer in the brain. ApoER2 signaling appears to require interaction between its cytoplasmic domain and adapter molecules such as Dab1, JIP 1 and JIP 2, and PSD-95. Many of the receptors for other signaling pathways affected by such adapter molecules are compartmentalized into specialized microdomains within the plasma membrane termed caveolae. Here, we show that apoER2, but not LDL-R, is localized to caveolae, supporting the concept that its physiological role is in cell signaling, rather than in endocytosing ligands.
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Affiliation(s)
- D R Riddell
- Department of Medicine, Royal Free and University College Medical School, University College London, Royal Free Campus, London NW3 2PF, United Kingdom
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Graham IR, Manzano A, Tagalakis AD, Mohri Z, Sperber G, Hill V, Beattie S, Schepelmann S, Dickson G, Owen JS. Gene repair validation. Nat Biotechnol 2001; 19:507-8. [PMID: 11385435 DOI: 10.1038/89209] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Tagalakis AD, Graham IR, Riddell DR, Dickson JG, Owen JS. Gene correction of the apolipoprotein (Apo) E2 phenotype to wild-type ApoE3 by in situ chimeraplasty. J Biol Chem 2001; 276:13226-30. [PMID: 11278248 DOI: 10.1074/jbc.c000883200] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein (apo) E is a polymorphic plasma protein, synthesized mainly by liver. Here, we evaluate whether synthetic DNA-RNA oligonucleotides (chimeraplasts) can convert a dysfunctional isoform, apoE2 (C --> T, R158C), which causes Type III hyperlipidemia and premature atherosclerosis, into apoE3. First, we treated recombinant Chinese hamster ovary cells stably secreting apoE2 with a 68-mer apoE2 to apoE3 chimeraplast. About one-third of apoE2 was converted to apoE3, and the repair was stable through 12 passages. Subcloning treated cells produced both apoE2 and apoE3 clones. Direct sequencing and reverse transcription polymerase chain reaction confirmed the genotype, whereas phenotypic change was verified by isoelectric focusing and immunoblotting of secreted proteins. Second, we established that the APOE2 gene can be targeted both in vivo, using transgenic mice overexpressing human apoE2, and in chromosomal context, using cultured lymphocytes from a patient homozygous for the epsilon2 allele. We conclude that chimeraplasty has the potential to convert the apoE2 mutation in patients with Type III hyperlipidemia to apoE3.
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Affiliation(s)
- A D Tagalakis
- Department of Medicine, Royal Free and University College Medical School, London NW3 2PF, United Kingdom
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Affiliation(s)
- D P Wade
- CV Therapeutics Inc, Palo Alto, California, USA
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Stannard AK, Khan S, Graham A, Owen JS, Allen SP. Inability of plasma high-density lipoproteins to inhibit cell adhesion molecule expression in human coronary artery endothelial cells. Atherosclerosis 2001; 154:31-8. [PMID: 11137080 DOI: 10.1016/s0021-9150(00)00444-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High-density lipoproteins (HDL) have several antiatherogenic actions, including the ability to sequester cellular cholesterol, to protect low-density lipoproteins from oxidation and to inhibit platelet aggregation. An early event in atherogenesis is the adhesion and recruitment of blood monocytes, a process mediated by cell adhesion molecules (CAMs), including vascular cell adhesion molecule-1 (VCAM-1) which is rapidly synthesized by endothelial cells in response to cytokines. It has been reported that HDL limits CAM expression in cultured human umbilical vein endothelial cells (HUVECs), implying that HDL also protects at an early stage in lesion development. Here, we have studied HDL suppression of CAM induction in human coronary artery endothelial cells (HCAECs), a model directly relevant to blood vessels susceptible to atherosclerosis. Arterial endothelial cells were preincubated with increasing amounts of total HDL, or different subfractions, and then activated with the inflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha). Flow cytometric analysis failed to detect any downregulation of VCAM-1 or E-selectin expression by HDL in this model of vascular endothelium. Moreover, we were unable to confirm that HDL could suppress CAM induction in well-characterized, low-passage HUVECs, even though positive controls, 17beta-estradiol or a nitric oxide donor, did cause downregulation and factors such as variability in donors and HDL preparation, or culture conditions, were excluded. We tentatively conclude that, as isolated HDL did not downregulate CAM expression in cultured HCAECs or HUVECs, attenuation of CAM induction in arterial endothelium is unlikely to contribute to HDL antiatherogenic actions in vivo.
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Affiliation(s)
- A K Stannard
- Department of Medicine, Royal Free and University College Medical School, University College London, Royal Free Campus, NW3 2PF, London, UK
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20
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Athanasopoulos T, Owen JS, Hassall D, Dunckley MG, Drew J, Goodman J, Tagalakis AD, Riddell DR, Dickson G. Intramuscular injection of a plasmid vector expressing human apolipoprotein E limits progression of xanthoma and aortic atheroma in apoE-deficient mice. Hum Mol Genet 2000; 9:2545-51. [PMID: 11030760 DOI: 10.1093/hmg/9.17.2545] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Apolipoprotein-E (apoE) protects against coronary artery disease via hepatic removal of atherogenic remnant lipoproteins, sequestration of cholesterol from vessel walls and local anti-oxidant, anti-platelet and anti-inflammatory actions. ApoE gene transfer may thus ameliorate a hyperlipidaemic profile and have beneficial effects at lesion sites to prevent or regress atherosclerosis, a concept endorsed by adenoviral-mediated hepatic expression studies. Here, using plasmid vectors expressing allelic human apoE2 or apoE3 isoforms, skeletal muscle was evaluated as an effective secretory platform for apoE gene augmentation. Transfected myoblasts and myotubes were found to efficiently secrete recombinant apoE in vitro as spherical 10-16 nm lipoprotein particles with pre-beta mobility. Intramuscular plasmid injection in apoE(-/-) mice, which develop spontaneous atherosclerotic plaque and xanthoma resulted in expression and secretion of apoE. Human apoE mRNA was detected by RT-PCR in injected muscles and, although concentrations of apoE3, which is rapidly cleared from plasma, were near ELISA detection limits, levels of plasma apoE2 were measurable (17.5 +/- 4.3 ng/ml). To assess whether muscle-based expression of apoE2 could inhibit atherogenesis, long-term follow-up studies were conducted. Although hyperlipidaemia was not reduced in treated animals, end-point pathology showed clear retardation of atherosclerotic and xanthomatous lesions. Up to 9 months following a single apoE2 plasmid administration, atherosclerotic lesion coverage in proximal aorta was significantly reduced by 20-30% (P < 0.01), whereas development of gross dorsal xanthoma (>5 mm diameter) was effectively reduced to zero. We conclude that expression of apoE from ectopic muscle sites has therapeutic potential to limit progression of atherosclerosis.
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Affiliation(s)
- T Athanasopoulos
- Division of Biochemistry, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 OEX, UK
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21
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Fan L, Owen JS, Dickson G. Construction and characterization of polycistronic retrovirus vectors for sustained and high-level co-expression of apolipoprotein A-I and lecithin-cholesterol acyltransferase. Atherosclerosis 1999; 147:139-45. [PMID: 10525135 DOI: 10.1016/s0021-9150(99)00191-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Apolipoprotein A-I (apo A-I) and lecithin-cholesterol acyltransferase (LCAT) are constituents of circulating high-density lipoprotein (HDL) particles and play an important role in 'reverse cholesterol transport', the process by which cholesterol in peripheral tissues is transferred to the liver for excretion. Enhancing levels of apo A-I, as well as LCAT, in plasma may promote the removal of excess cholesterol from the arterial wall and thus reduce the formation of atherosclerotic lesions. Indeed, both apo A-I and LCAT genes have been identified as therapeutic targets to prevent or limit atherogenesis. Here, we have constructed two retroviral vectors, one containing LCAT cDNA and the neomycin phosphotransferase (NEO) gene (pLLEN), the other apo A-I cDNA, LCAT cDNA and the NEO gene (pLAPLEN) linked by internal ribosome entry sites (IRES). Both bi- and tricistronic retroviral vectors efficiently co-expressed their two or three genes when transfected into cultured mouse C2C12 muscle cells or human 293 cells. After 30 days, the retroviral vector sequences were retained by the host cells, whereas those of a conventional plasmid vector were lost. Moreover, transduced C2C12 mouse myoblasts maintained the ability for heterologous expression of human LCAT and apo A-I even after differentiation into myotubes. Stably-transduced clones of C2C12 cells were selected by neomycin (G418) resistance and continued to efficiently express human LCAT for 60 days. These findings indicate that the use of polycistronic retrovirus vectors to genetically modify myoblasts, which can be transplanted back into skeletal muscle, might be a safe and feasible strategy to express human apo A-I and LCAT and hence have therapeutic potential to regress atherosclerotic lesions.
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Affiliation(s)
- L Fan
- Division of Biochemistry, School of Biological Sciences, Royal Holloway University of London, Egham, UK
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22
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Affiliation(s)
- J S Owen
- Department of Medicine, Royal Free and University College Medical School, University College London, UK
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23
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Riddell DR, Vinogradov DV, Stannard AK, Chadwick N, Owen JS. Identification and characterization of LRP8 (apoER2) in human blood platelets. J Lipid Res 1999; 40:1925-30. [PMID: 10508213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Recently, we reported that apoE inhibits platelet reactivity by stimulating NO release and postulated apoE-receptor activation of intracellular NO synthase (eNOS). Here, we implicate a low density lipoprotein receptor (LDL-R) family member by studying ligand requirements using purified apoE isoforms, synthetic peptides, and the receptor antagonist, receptor-associated protein (RAP). Then, using a homology cloning approach and degenerate PCR primers to amplify the conserved Cys-rich binding domain of the LDL-R family, this receptor was identified as LRP8 (formerly termed, apoER2), a newly described brain protein with several splice variants. Immunoprecipitation of platelet membranes with anti-peptide antisera confirmed protein expression, while analysis of RNA from platelets and two megakaryocytic cell lines (Meg-01 and HEL) disclosed that the major LRP8 transcript lacked binding repeats 4-6 (LRP8delta4-6) but contained the full-length cytoplasmic tail. Sequence analysis of cytoplasmic LRP8 revealed several peptide motifs with potential for cellular signaling and we propose this as a rational mechanism through which apoE inhibits platelet aggregation.
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Affiliation(s)
- D R Riddell
- Department of Medicine, Royal Free and University College Medical School, University College London, Royal Free Campus, London NW3 2PF, United Kingdom
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24
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Abstract
Platelets are small cells, 1/14th the volume of erythrocytes, and about 1000 billion circulate in human blood as smooth anucleate disks. Their job is to survey the lining of our blood vessels, the endothelium. In acute damage and extravasation, platelets are activated by contact with exposed collagen and aggregate together at the wound sites to initiate clotting and stop bleeding. Forming a physical plug to seal a hemorrhaging vessel is the key role of blood platelets. However, milder injury to the endothelium, perhaps a result of high blood pressure, raised plasma cholesterol, or smoking, also causes platelets to adhere to the internal walls of arteries. Such precipitate adhesion and activation of platelets initiates an inflammatory response of the vessel wall and predisposes to vascular complications, including thrombosis, premature heart disease, myocardial infarcts or strokes, and diabetes. It is essential, therefore, that during normal vascular hemostasis platelet activation is tightly controlled. Indeed, both platelets and endothelial cells produce and secrete chemicals that directly inhibit platelet aggregation. A key agent is the free radical gas nitric oxide (NO). Here, we review how this 30-Da molecular messenger is synthesized by a catalytic cassette 10,000 times larger and how it functions to suppress platelet "stickiness." We also present new evidence that directly links plasma lipoproteins with platelet activation: we describe at the molecular level how apoE, a protein with a prominent role in cholesterol transport, interacts with the platelet surface to stimulate NO production and hence attenuate platelet activation.
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Affiliation(s)
- D R Riddell
- Department of Medicine, Royal Free and University College Medical School, London, England
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25
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Winder AF, Owen JS, Pritchard PH, Lloyd-Jones D, Vallance DT, White P, Wray R. A first British case of fish-eye disease presenting at age 75 years: a double heterozygote for defined and new mutations affecting LCAT structure and expression. J Clin Pathol 1999; 52:228-30. [PMID: 10450185 PMCID: PMC501085 DOI: 10.1136/jcp.52.3.228] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Fish-eye disease is a familial syndrome with corneal opacification, major high density lipoprotein (HDL) deficiency in plasma, significant cholesterol esterification in plasma on non-HDL lipoproteins, generally without premature coronary disease. This first British male case from unrelated British parents had infarcts when aged 49 and 73 years but was asymptomatic at age 81 years, with plasma cholesterol 4.3-7.1 mmol/litre, triglycerides 1.8-2.2 mmol/litre, HDL cholesterol < 0.1 mmol/litre, apolipoprotein A-I < 0.16 g/litre, lipoprotein(a) 0.61 g/litre. Cholesterol esterification was impaired using HDL-3 and A-I proteoliposomes but not using VLDL/IDL/LDL. The findings are those of LCAT deficiency with the classic fish-eye disease defect. Most of the 22 reported cases were homozygous or heterozygous for a Thr-Ile mutation at codon 123 of the lecithin:cholesterol acyltransferase (LCAT) gene. This patient was a double heterozygote for this mutation and a second new incompletely defined mutation affecting LCAT expression as defined by reduced mass and activity in plasma.
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Affiliation(s)
- A F Winder
- University Department of Molecular Pathology and Clinical Biochemistry, Royal Free and University College School of Medicine, London, UK.
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26
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Fan L, Drew J, Dunckley MG, Owen JS, Dickson G. Efficient coexpression and secretion of anti-atherogenic human apolipoprotein AI and lecithin-cholesterol acyltransferase by cultured muscle cells using adeno-associated virus plasmid vectors. Gene Ther 1998; 5:1434-40. [PMID: 9930350 DOI: 10.1038/sj.gt.3300746] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Plasma apolipoprotein AI (apoAI) and lecithin-cholesterol acyltransferase (LCAT) play important roles in reverse cholesterol transport, promoting the removal of excess cholesterol from peripheral cells and reducing formation of atherosclerotic lesions. Gene augmentation of either apoAI or LCAT, or both, are thus attractive targets for prevention or treatment of atherosclerosis. With the eventual aim of safe and efficient gene delivery to skeletal muscle, our chosen secretory platform for systemic delivery of anti-atherogenic proteins, we have constructed conventional and AAV-based plasmid vectors containing human apoAI or LCAT cDNAs; their efficacy was tested by lipoplex transfection of mouse C2C12 muscle cells or human 293 cells. The secretion of apoAI or LCAT by transduced cultures was two- to five-fold higher using AAV-based plasmid vectors than conventional plasmid vectors. Additionally, cells transfected with a bicistronic AAV-based vector containing an internal ribosome entry site (IRES) efficiently expressed both apoAI and LCAT simultaneously. Furthermore, AAV-based vector sequences were retained by host cells, whereas those of conventional plasmid vectors were lost. These studies indicate that ectopic overexpression of apoAI and LCAT in muscle tissue using AAV-based plasmid vectors might provide a feasible anti-atherogenic strategy in vivo.
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Affiliation(s)
- L Fan
- Division of Biochemistry, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK
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27
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Lima VL, Sena VL, Stewart B, Owen JS, Dolphin PJ. An evaluation of the marmoset Callithrix jacchus (sagüi) as an experimental model for the dyslipoproteinemia of human Schistosomiasis mansoni. Biochim Biophys Acta 1998; 1393:235-43. [PMID: 9748601 DOI: 10.1016/s0005-2760(98)00076-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human infection with the parasite Schistosoma mansoni is a relatively common occurrence in regions of South America and is associated with liver dysfunction and dyslipoproteinemia. Specifically, the activity of plasma lecithin:cholesterol acyltransferase (LCAT) activity is reduced, the concentration of plasma cholesterol esters falls, phospholipid concentrations are elevated and erythrocyte membranes become cholesterol enriched. Previous studies have utilized rodents (rats and mice) as experimental models to study the dyslipoproteinemia induced by S. mansoni infection. However, the plasma lipoprotein profiles in these animals is very different from humans and infection is not accompanied by decreases in LCAT activity or cholesterol enrichment of their erythrocyte membranes. Here we have evaluated the suitability of the marmoset Callithrix jacchus (sagüi) which is small and readily available in Brazil, as a potential animal model for the study of the dyslipoproteinemia of S. mansoni infections. The plasma lipoprotein compositions and distributions in sagüi, unlike rats or mice, approximate those of man with the LDL representing a major lipoprotein species. The molecular species of phospholipids, cholesterol esters and triglycerides present in sagüi plasma are also very similar to man, whereas those of rats and mice favor the longer chain more unsaturated species, Sagüi, like rodents, can be successfully infected with S. mansoni and after 60 days, this results in a 50% reduction in plasma LCAT activity, an 11% reduction in plasma cholesterol esters, an absolute increase of 46% in plasma phospholipids and an 18% increase in the cholesterol content of erythrocyte membranes. These changes are qualitatively and quantitatively very similar to those previously reported following human infections. Based upon these changes, and the observation that the plasma lipoprotein profile of sagüi and human is similar, we conclude that C. jacchus (sagüi) is an appropriate animal model for the study of dyslipoproteinemia associated with S. mansoni infections.
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Affiliation(s)
- V L Lima
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Brazil
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28
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Riddell DR, Siripurapu V, Vinogradov DV, Gliemann J, Owen JS. Blood platelets do not contain the low-density receptor-related protein (LRP). Biochem Soc Trans 1998; 26:S244. [PMID: 9765963 DOI: 10.1042/bst026s244] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- D R Riddell
- University Department of Medicine, Royal Free Hospital School of Medicine, London, England
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29
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Abstract
Elimination of cholesterol from arterial tissue, crucial in limiting atherogenesis, may be achieved via high-density lipoprotein (HDL)-mediated reverse cholesterol transport (RCT); components of this pathway can be modulated by oxidative stress. Here we have examined the relations between cholesterol efflux, esterification and transfer in human plasma treated with the powerfully reactive nitrogen species, peroxynitrite. Cellular cholesterol efflux to whole plasma, or to peroxynitrite-modified HDL3, was relatively insensitive to peroxynitrite, as was the transfer of esterified cholesterol. However, plasma cholesterol esterification, via lecithin:cholesterol acyltransferase (LCAT), was markedly inhibited, both directly and indirectly, by peroxynitrite treatment, implying inefficient RCT follows HDL sequestration of cellular cholesterol.
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Affiliation(s)
- A Graham
- Department of Biochemistry and Molecular Biology, Royal Free Hospital School of Medicine, London, UK.
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30
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Stannard AK, Riddell DR, Bradley NJ, Hassall DG, Graham A, Owen JS. Apolipoprotein E and regulation of cytokine-induced cell adhesion molecule expression in endothelial cells. Atherosclerosis 1998; 139:57-64. [PMID: 9699892 DOI: 10.1016/s0021-9150(98)00052-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Atherosclerotic plaques develop in the arterial wall from complex multicellular processes following the early recruitment of circulating monocytes. Infiltration of monocytes is mediated by cell adhesion molecules (CAMs), including vascular cell adhesion molecule-1 (VCAM-1) which is rapidly induced in endothelial cells in response to cytokines. Apolipoprotein E (apo E), a 34-kDa polypeptide, helps protect against atherosclerosis, in part, because apo E phospholipid particles secreted by macrophages may have local protective effects within lesions. Here we have investigated whether purified plasma apo E, complexed with dimyristoyl phosphatidylcholine (DMPC) vesicles, can inhibit cytokine-induced vascular cell adhesion molecule-1 (VCAM-1) expression in human umbilical vein endothelial cells (HUVECs). Expression of VCAM-1 in endothelial cells after exposure to tumour necrosis factor-alpha (TNF-alpha) or interleukin 1beta (IL-1beta) was quantified by ELISA and shown to be partially inhibited by 17beta-estradiol (40-60% inhibition) or by S-nitroso-L-glutathione, a nitric oxide donor (20-25%). However, preincubations with physiological concentrations (10-100 microg protein/ml) of apo E DMPC did not downregulate VCAM-1 expression, even with extended preincubation times. These findings were confirmed using a fluorescence-activated cell sorter (FACS) for analysis which indicated additionally that apo E-DMPC had no effect on sub-populations within the HUVEC cultures. Finally, apo E-DMPC vesicles were also unable to suppress TNF-alpha-induced upregulation of E-selectin or intercellular adhesion molecule-1 (ICAM-1). We conclude that plasma apo E is unlikely to be important in limiting endothelial activation.
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Affiliation(s)
- A K Stannard
- University Department of Medicine, Royal Free Hospital School of Medicine, London, UK
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31
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Chawla D, Malik AM, Lima VL, Owen JS. Immunoaffinity-isolation of plasma lecithin-cholesterol acyltransferase (LCAT) from patients with hepatic cirrhosis. Biochem Soc Trans 1998; 26:S147. [PMID: 9649822 DOI: 10.1042/bst026s147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- D Chawla
- University Department of Medicine, Royal Free Hospital School of Medicine, London, UK
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32
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Rafique S, Owen JS. Plasma, platelet and erythrocyte lipids in the Watanabe heritable hyperlipidaemic (WHHL) rabbit. Biochem Soc Trans 1998; 26:S148. [PMID: 9649823 DOI: 10.1042/bst026s148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- S Rafique
- University Department of Medicine, Royal Free Hospital School of Medicine, London, UK
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33
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Affiliation(s)
- D V Vinogradov
- University Department of Medicine, Royal Free Hospital School of Medicine, London, UK
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34
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Abstract
One mechanism by which plasma high-density lipoprotein (HDL) may protect against atherogenesis is by inhibiting the oxidation of low-density lipoprotein (LDL). Recent evidence suggests that paraoxonase, an HDL-associated, calcium-dependent enzyme, may be responsible for the antioxidant action of HDL (Mackness et al., Atherosclerosis 1993;104:129; Mackness et al., FEBS Lett 1991;286:152; Watson et al., J Clin Invest 1995;96:2882; Navab et al., Arterio Thromb Vasc Biol 1996;16:831); in particular, paraoxonase activity inhibits the formation of 'minimally oxidized' LDL by hydrolyzing biologically active oxidized phospholipids (Watson et al., J Clin Invest 1995;96:2882; Navab et al., Arterio Thromb Vasc Biol 1996;16:831). However, antioxidant effects of HDL have also been demonstrated under calcium-free conditions, arguing that this enzyme may not be the only mechanism by which HDL inhibits LDL oxidation (Tribble et al., J Lipid Res 1995;36:2580). Here we have evaluated the role of paraoxonase in prevention of LDL oxidation by using HDL subfractions, isolated from human serum or EDTA-plasma, which display markedly different levels of paraoxonase activity; the abilities of modified forms of HDL to prevent LDL oxidation by cultured human (THP-1) macrophages were also assessed. Paraoxonase activity was substantially lower in HDL prepared from plasma compared to serum HDL; moreover, virtually all of the lipoprotein-associated paraoxonase activity was located in the HDL3 fraction, with HDL2 retaining only 1-5% of the total activity. Despite possessing 5-fold differences in paraoxonase activity, HDL3 isolated from plasma or serum was equally effective in inhibiting LDL oxidation by THP-1 macrophages; furthermore, although plasma HDL3 was more protective than plasma HDL2, the latter did significantly inhibit LDL oxidation. Non-paraoxonase antioxidant constituents of plasma HDL3 were investigated further. ApoHDL3, the totally delipidated form of HDL3, was much less effective than native HDL3; when examined individually, purified apolipoprotein A-II gave greater protection than apo A-I, although this effect was not evident in apo A-II-enriched HDL3. Partial delipidation of HDL3, which removes both neutral lipids and alpha-tocopherol, did not significantly diminish its ability to inhibit LDL oxidation by THP-1 macrophages; phospholipid vesicles prepared from partially delipidated HDL3 also inhibited LDL oxidation effectively. We conclude that, in this model of cellular LDL oxidation, the phospholipid fraction of HDL exerts inhibitory effects which are independent of HDL paraoxonase activity.
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Affiliation(s)
- A Graham
- Department of Biochemistry and Molecular Biology, Royal Free Hospital School of Medicine, London, UK.
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35
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Stannard AK, Bradley NJ, Owen JS. Evaluation of the ECV304 spontaneously transformed HUVEC cell line for adhesion molecule research. Biochem Soc Trans 1997; 25:486S. [PMID: 9388707 DOI: 10.1042/bst025486s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- A K Stannard
- Royal Free Hospital School of Medicine, University Department of Medicine, London, U.K
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36
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Riddell DR, Graham A, Owen JS. Apolipoprotein E inhibits platelet aggregation through the L-arginine:nitric oxide pathway. Implications for vascular disease. J Biol Chem 1997; 272:89-95. [PMID: 8995232 DOI: 10.1074/jbc.272.1.89] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We have previously reported that plasma apolipoprotein (apo) E-containing high density lipoprotein particles have a potent anti-platelet action, apparently by occupying saturable binding sites in the cell surface. Here we show that purified apoE (10-50 microg/ml), complexed with phospholipid vesicles (dimyristoylphosphatidylcholine, DMPC), suppresses platelet aggregation induced by ADP, epinephrine, or collagen. This effect was not due to sequestration of cholesterol from platelet membranes; apoE x DMPC chemically modified with cyclohexanedione (cyclohexanedione-apoE x DMPC) did not inhibit aggregation but nevertheless removed similar amounts of cholesterol as untreated complexes, about 2% during the aggregation period. Rather we found that apoE influenced intracellular platelet signaling. Thus, apoE x DMPC markedly increased cGMP in ADP-stimulated platelets which correlated with the resulting inhibition of aggregation (r = 0.85; p < 0.01, n = 10), whereas cyclohexanedione-apoE x DMPC vesicles had no effect. One important cellular mechanism for up-regulation of cGMP is through stimulation of nitric oxide (NO) synthase, the NO generated by conversion of L-arginine to L-citrulline, binds to and activates guanylate cyclase. This signal transduction pathway was implicated by the finding that NO synthase inhibitors of distinct structural and functional types all reversed the anti-platelet action of apoE, whereas a selective inhibitor of soluble guanylate cyclase, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (100 nM), had a similar reversing action. Direct confirmation that apoE stimulates NO synthase was obtained by use of L-[3H]arginine; platelets pretreated with apoE x DMPC produced markedly more L-[3H]citrulline (0.71 +/- 0.1 pmol/h/10(9) platelets) than controls (0.18 +/- 0.03; p < 0.05). In addition, hemoglobin which avidly binds NO also suppressed the anti-aggregatory effect, indicating that apoE stimulated sufficient production of NO by platelets for extracellular release to occur. We conclude that apoE inhibits platelet aggregation through the L-arginine:NO signal transduction pathway.
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Affiliation(s)
- D R Riddell
- University Department of Medicine, Royal Free Hospital School of Medicine, London, United Kingdom
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37
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Riddell DR, Sheikh S, James RW, Owen JS. Native immunoaffinity-isolated apolipoprotein E-containing high-density lipoprotein particles inhibit platelet aggregation. Biochem Soc Trans 1996; 24:454S. [PMID: 8878998 DOI: 10.1042/bst024454s] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- D R Riddell
- University Department of Academic Medicine, Royal Free Hospital School of Medicine, London, UK
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38
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Affiliation(s)
- A Graham
- Royal Free Hospital School of Medicine, Academic Dept. of Medicine, London
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39
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Bundy RE, Owen JS, Lima VL, Chaves EM. Trypanolytic activity in vivo of plasma from patients with schistosomiasis against the African trypanosome, Trypanosoma brucei brucei. Biochem Soc Trans 1996; 24:439S. [PMID: 8878983 DOI: 10.1042/bst024439s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- R E Bundy
- Medical Unit, Royal Free Hospital School of Medicine, London, England
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40
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Lima VL, Harry DS, McIntyre N, Owen JS, Chaves ME. Characterization and potential uses of rabbit polyclonal antibodies against human plasma lecithin-cholesterol acyltransferase. Braz J Med Biol Res 1996; 29:957-68. [PMID: 9181076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Familial and secondary deficiency of plasma lecithin-cholesterol acyltransferase (LCAT) produce circulating lipoprotein particles with gross structural and compositional abnormalities; these have adverse effects on a variety of cellular functions. Factors affecting hepatic synthesis and secretion of this plasma enzyme are largely unknown but, potentially, some of them can be investigated with monospecific antibodies. In the present study, enzymically active LCAT was purified 40,000-fold from human plasma and then used to raise polyclonal antibodies in New Zealand White rabbits. Addition of this antiserum (1 microliter) to human plasma (25 microlitres) completely inhibited LCAT activity, although it was less effective against plasma from other species. The antibodies appeared to be monospecific to plasma LCAT. They gave a single precipitin arc by crossed immunoelectrophoresis, while immunodiffusion established that there was no cross-reactivity with several apolipoproteins or with serum albumin. Moreover, the antiserum was successfully used to detect LCAT in normal human plasma by Laurell rocket immunoelectrophoresis. By contrast, Western blotting of plasma proteins using whole LCAT antiserum was largely unsuccessful because of high background staining, although this could be substantially reduced by use of an IgG fraction. However, the whole antiserum readily immunoprecipitated LCAT secreted into the culture medium of HepG2 cells, a human hepatoblastoma cell line, pre-labelled with [35S]methionine, the [35S]-labelled LCAT appearing as a narrow 65-kDa protein band by electrophoresis and fluorography. We conclude that polyclonal antibodies may be an important tool to investigate the characteristics and underlying mechanisms of secondary LCAT deficiencies, including those associated with hepatic cirrhosis and schistosomiasis.
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Affiliation(s)
- V L Lima
- Departamento de Bioquimica, Universidade Federal de Pernambuco, Recife, Brasil
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Owen JS, Lorenz P, Betschart B. HDL particles as the trypanosome-killing factor in human serum: An exclusive or inconclusive role? ACTA ACUST UNITED AC 1996; 12:250-1. [PMID: 15275208 DOI: 10.1016/0169-4758(96)80814-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Streather CP, Owen JS, Hendry BM, Scoble JE. Incubation of porcine high-density lipoprotein with the apical surface of LLC-PK1 renal tubular cells sustains the properties of orientated monolayers. Nephrol Dial Transplant 1996. [DOI: 10.1093/oxfordjournals.ndt.a027307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Streather CP, Owen JS, Hendry BM, Scoble JE. Incubation of porcine high-density lipoprotein with the apical surface of LLC-PK1 renal tubular cells sustains the properties of orientated monolayers. Nephrol Dial Transplant 1996; 11:431-7. [PMID: 8671811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND HDL is present in the urine of patients with the nephrotic syndrome. The amount of HDL is directly related to the protein selectivity and therefore to the renal prognosis. Urinary HDL may therefore be involved in the pathogenesis of progressive renal impairment in proteinuric renal disease. METHODS LLC-PK1 cells were grown as orientated monolayers on filters. Uptake of HDL and permeability to inulin were measured. The influence of HDL in the growth medium on monolayer resistance, protein content, and sodium dependent glucose transport was studied. The effects of tetranitromethane (TNM) nitrosylation of HDL and of albumin, mevalonate, or simvastatin were investigated. RESULTS Confluent LLC-PK1 monolayers took up fluorescently labelled HDL from either epithelial surface and formed a significant diffusion barrier to inulin. Monolayers incubated in 300 micrograms/ml HDL achieved a protein content and plateau of resistance equal to those in 10% fetal calf serum (FCS); 30-1000 micrograms/ml HDL applied to the apical surface of confluent monolayers maintained a plateau of resistance as well as 10% FCS and significantly better than serum-free medium. Sodium-dependent glucose transport was preserved in monolayers exposed to HDL. Simvastatin completely, and nitrosylation partially, removed the stimulatory properties of HDL. These were partly reproduced by albumin or mevalonate. CONCLUSIONS HDL can enter renal epithelial cells from the apical surface. HDL added to this surface at confluence, reproducing the conditions found in the nephrotic syndrome, had a measurable positive effect on monolayer resistance. Results with nitrosylated HDL and HMG-CoA blockade suggest that these effects may be mediated via receptors and this enzyme system.
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Affiliation(s)
- C P Streather
- Department of Medicine, King's College School of Medicine and Dentistry, London, UK
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Abstract
We have previously shown that plasma HDL-E, a minor subclass of high-density lipoproteins (HDL) containing apolipoprotein (apo) E, has a potent anti-platelet effect and implicated apoE as the active constituent. Recently, apoE complexes with phospholipids (DMPC) were reported to inhibit thrombin-induced aggregation by sequestering platelet membrane cholesterol. Here we demonstrate that platelet cholesterol depletion is an improbable explanation for the suppressive effect of apoE:DMPC on ADP-mediated platelet aggregation; only 0.5% of cholesterol was released prior to addition of ADP to initiate aggregation while lactoferrin, which does not accept cellular cholesterol, was also inhibitory. Previous studies have shown that apoE and lactoferrin are both bound by platelets but whether this provides the initial stimulus for suppression of aggregation remains to be established.
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Affiliation(s)
- D R Riddell
- University Department of Medicine, Royal Free Hospital School of Medicine, London, UK
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Owen JS, Wiebusch H, Cullen P, Watts GF, Lima VL, Funke H, Assmann G. Complete deficiency of plasma lecithin-cholesterol acyltransferase (LCAT) activity due to a novel homozygous mutation (Gly-30-Ser) in the LCAT gene. Hum Mutat 1996; 8:79-82. [PMID: 8807342 DOI: 10.1002/(sici)1098-1004(1996)8:1<79::aid-humu13>3.0.co;2-o] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- J S Owen
- University Department of Medicine, Royal Free Hospital School of Medicine, London, UK
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Abstract
We have previously shown that plasma HDL-E, a minor subclass of high-density lipoproteins (HDL) containing apolipoprotein (apo) E, has a potent anti-platelet effect and implicated apoE as the active constituent. Recently, apoE complexes with phospholipids (DMPC) were reported to inhibit thrombin-induced aggregation by sequestering platelet membrane cholesterol. Here we demonstrate that platelet cholesterol depletion is an improbable explanation for the suppressive effect of apoE:DMPC on ADP-mediated platelet aggregation; only 0.5% of cholesterol was released prior to addition of ADP to initiate aggregation while lactoferrin, which does not accept cellular cholesterol, was also inhibitory. Previous studies have shown that apoE and lactoferrin are both bound by platelets but whether this provides the initial stimulus for suppression of aggregation remains to be established.
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Affiliation(s)
- D R Riddell
- University Department of Medicine, Royal Free Hospital School of Medicine, London, UK
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Lorenz P, Owen JS, Hassall DG. Human serum resistant Trypanosoma brucei rhodesiense accumulates similar amounts of fluorescently-labelled trypanolytic human HDL3 particles as human serum sensitive T.b. brucei. Mol Biochem Parasitol 1995; 74:113-8. [PMID: 8719251 DOI: 10.1016/0166-6851(95)02479-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- P Lorenz
- Swiss Tropical Institute, Basel, Switzerland.
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Lorenz P, Betschart B, Owen JS. Trypanosoma brucei brucei and high-density lipoproteins: Old and new thoughts on the identity and mechanism of the trypanocidal factor in human serum. ACTA ACUST UNITED AC 1995; 11:348-52. [PMID: 15275320 DOI: 10.1016/0169-4758(95)80191-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Nature has provided humans with a surprising means of protection against the African trypanosome Trypanosoma brucei brucei There is consensus, in that this singular trypanocidal factor is serum high-density lipoproteins (HDL). which the trypanosomes engulf through a physiological, receptor-mediated pathway for delivery to acidic intracellular vesicles. There is also controversy, however, in that the active particles and their essential cytotoxic elements are disputed, in part reflecting the ill-defined mechanism by which the parasites are finally killed. Here Patrick Lorenz, Bruno Betschart and Jim Owen discuss the possibilities for resolving these discrepancies and speculate on the prospects of exploiting this unexpected property of human HDL for protecting livestock.
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Affiliation(s)
- P Lorenz
- Zentrum für Molekulare Biologie, Universität Heidelberg, Postfach 10 62 49, D-69120 Heidelberg, Germany
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Watts GF, Mitropoulos KA, al-Bahrani A, Reeves BE, Owen JS. Lecithin-cholesterol acyltransferase deficiency presenting with acute pancreatitis: effect of infusion of normal plasma on triglyceride-rich lipoproteins. J Intern Med 1995; 238:137-41. [PMID: 7629481 DOI: 10.1111/j.1365-2796.1995.tb00911.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A 38-year-old Asian man presented with acute pancreatitis, marked hypertriglyceridaemia and macroproteinuria, 20 years after the diagnosis of lecithin-cholesterol acyltransferase (LCAT) deficiency. After recovery, he exhibited macroproteinuria and chylomicronaemia despite treatment with a very-low-fat diet. Infusion of normal plasma significantly increased the proportion of cholesterol esters in the patient's plasma and significantly lowered chylomicron-triglyceride levels, but not proteinuria. We conclude that renal dysfunction may be a late manifestation of LCAT deficiency and that it may lead to severe chylomicronaemia and acute pancreatitis. Infusion of normal plasma corrects the dyslipidaemia in LCAT deficiency, but in the short term does not improve renal function.
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Affiliation(s)
- G F Watts
- University Department of Medicine, University of Western Australia, Royal Perth Hospital
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Chawla D, Owen JS. Secretion of active human lecithin-cholesterol acyltransferase by insect cells infected with a recombinant baculovirus. Biochem J 1995; 309 ( Pt 1):249-53. [PMID: 7619064 PMCID: PMC1135827 DOI: 10.1042/bj3090249] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Difficulties in purifying the plasma enzyme lecithin-cholesterol acyltransferase (LCAT) have hampered detailed studies of its (patho)physiological role in lipoprotein metabolism and of structure-function relationships. Potentially, baculovirus-driven expression systems offer a powerful means to produce significant amounts of LCAT. Accordingly, full-length LCAT cDNA was cloned into pVL 1392, a high-level expression derivative of Autographa californica nuclear polyhedrosis virus (AcNPV), and the resultant plasmid was co-transfected into Trichoplusia ni insect cells (High 5 line) with a linearized viral DNA using lipofectin. Such viral DNA had a lethal mutation and grew only when recombined with a pVL1392-type rescue plasmid; cells infected with recombinant Autographa californica LCAT virus changed from a fibroblast-like morphology to rounded, but lacked the polyhedrin occlusion bodies characteristic of wild-type AcNPV infections. Enzymically active recombinant LCAT (rLCAT), sensitive to sulphydryl reagents, was secreted in the late phase of infection (36-48 h) but was absent with wild-type infections. The secreted protein had an apparent molecular mass of 53 kDa by SDS/PAGE, lower than that of native plasma LCAT; it was susceptible to endoglycosidase H digestion and was bound by concanavalin A, suggesting that precursor high-mannose N-glycan chains had not undergone full maturation to complex types. Pretreatment of the cells with tunicamycin to inhibit the first step of N-glycosylation led to intracellular accumulation of immature rLCAT (approximately 46-48 kDa) and a marked reduction in enzyme secreted. We conclude that the baculovirus gene-expression system will permit production of biologically active normal and mutant forms of LCAT protein.
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Affiliation(s)
- D Chawla
- University Department of Medicine, Royal Free Hospital School of Medicine, London, U.K
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