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Sample records for ldl apo b-100

  1. Impact of myeloperoxidase-LDL interactions on enzyme activity and subsequent posttranslational oxidative modifications of apoB-100

    PubMed Central

    Delporte, Cédric; Boudjeltia, Karim Zouaoui; Noyon, Caroline; Furtmüller, Paul G.; Nuyens, Vincent; Slomianny, Marie-Christine; Madhoun, Philippe; Desmet, Jean-Marc; Raynal, Pierre; Dufour, Damien; Koyani, Chintan N.; Reyé, Florence; Rousseau, Alexandre; Vanhaeverbeek, Michel; Ducobu, Jean; Michalski, Jean-Claude; Nève, Jean; Vanhamme, Luc; Obinger, Christian; Malle, Ernst; Van Antwerpen, Pierre

    2014-01-01

    Oxidation of LDL by the myeloperoxidase (MPO)-H2O2-chloride system is a key event in the development of atherosclerosis. The present study aimed at investigating the interaction of MPO with native and modified LDL and at revealing posttranslational modifications on apoB-100 (the unique apolipoprotein of LDL) in vitro and in vivo. Using amperometry, we demonstrate that MPO activity increases up to 90% when it is adsorbed at the surface of LDL. This phenomenon is apparently reflected by local structural changes in MPO observed by circular dichroism. Using MS, we further analyzed in vitro modifications of apoB-100 by hypochlorous acid (HOCl) generated by the MPO-H2O2-chloride system or added as a reagent. A total of 97 peptides containing modified residues could be identified. Furthermore, differences were observed between LDL oxidized by reagent HOCl or HOCl generated by the MPO-H2O2-chloride system. Finally, LDL was isolated from patients with high cardiovascular risk to confirm that our in vitro findings are also relevant in vivo. We show that several HOCl-mediated modifications of apoB-100 identified in vitro were also present on LDL isolated from patients who have increased levels of plasma MPO and MPO-modified LDL. In conclusion, these data emphasize the specificity of MPO to oxidize LDL. PMID:24534704

  2. ApoB100-LDL Acts as a Metabolic Signal from Liver to Peripheral Fat Causing Inhibition of Lipolysis in Adipocytes

    PubMed Central

    Skogsberg, Josefin; Dicker, Andrea; Rydén, Mikael; Åström, Gaby; Nilsson, Roland; Bhuiyan, Hasanuzzaman; Vitols, Sigurd; Mairal, Aline; Langin, Dominique; Alberts, Peteris; Walum, Erik; Tegnér, Jesper; Hamsten, Anders; Arner, Peter; Björkegren, Johan

    2008-01-01

    Background Free fatty acids released from adipose tissue affect the synthesis of apolipoprotein B-containing lipoproteins and glucose metabolism in the liver. Whether there also exists a reciprocal metabolic arm affecting energy metabolism in white adipose tissue is unknown. Methods and Findings We investigated the effects of apoB-containing lipoproteins on catecholamine-induced lipolysis in adipocytes from subcutaneous fat cells of obese but otherwise healthy men, fat pads from mice with plasma lipoproteins containing high or intermediate levels of apoB100 or no apoB100, primary cultured adipocytes, and 3T3-L1 cells. In subcutaneous fat cells, the rate of lipolysis was inversely related to plasma apoB levels. In human primary adipocytes, LDL inhibited lipolysis in a concentration-dependent fashion. In contrast, VLDL had no effect. Lipolysis was increased in fat pads from mice lacking plasma apoB100, reduced in apoB100-only mice, and intermediate in wild-type mice. Mice lacking apoB100 also had higher oxygen consumption and lipid oxidation. In 3T3-L1 cells, apoB100-containing lipoproteins inhibited lipolysis in a dose-dependent fashion, but lipoproteins containing apoB48 had no effect. ApoB100-LDL mediated inhibition of lipolysis was abolished in fat pads of mice deficient in the LDL receptor (Ldlr−/−Apob100/100). Conclusions Our results show that the binding of apoB100-LDL to adipocytes via the LDL receptor inhibits intracellular noradrenaline-induced lipolysis in adipocytes. Thus, apoB100-LDL is a novel signaling molecule from the liver to peripheral fat deposits that may be an important link between atherogenic dyslipidemias and facets of the metabolic syndrome. PMID:19020660

  3. Conformational changes of apoB-100 in SMase-modified LDL mediate formation of large aggregates at acidic pH[S

    PubMed Central

    Nguyen, Su Duy; Pihlajamaa, Tero; Yohannes, Gebrenegus; Riekkola, Marja-Liisa; Milne, Ross; Öörni, Katariina

    2012-01-01

    During atherogenesis, the extracellular pH of atherosclerotic lesions decreases. Here, we examined the effect of low, but physiologically plausible pH on aggregation of modified LDL, one of the key processes in atherogenesis. LDL was treated with SMase, and aggregation of the SMase-treated LDL was followed at pH 5.5–7.5. The lower the pH, the more extensive was the aggregation of identically prelipolyzed LDL particles. At pH 5.5–6.0, the aggregates were much larger (size >1 µm) than those formed at neutral pH (100–200 nm). SMase treatment was found to lead to a dramatic decrease in α-helix and concomitant increase in β-sheet structures of apoB-100. Particle aggregation was caused by interactions between newly exposed segments of apoB-100. LDL-derived lipid microemulsions lacking apoB-100 failed to form large aggregates. SMase-induced LDL aggregation could be blocked by lowering the incubation temperature to 15°C, which also inhibited the changes in the conformation of apoB-100, by proteolytic degradation of apoB-100 after SMase-treatment, and by HDL particles. Taken together, sphingomyelin hydrolysis induces exposure of protease-sensitive sites of apoB-100, whose interactions govern subsequent particle aggregation. The supersized LDL aggregates may contribute to the retention of LDL lipids in acidic areas of atherosclerosis-susceptible sites in the arterial intima. PMID:22717515

  4. Red wine polyphenolics increase LDL receptor expression and activity and suppress the secretion of ApoB100 from human HepG2 cells.

    PubMed

    Pal, Sebely; Ho, Nerissa; Santos, Carlos; Dubois, Paul; Mamo, John; Croft, Kevin; Allister, Emma

    2003-03-01

    Epidemiologic studies suggest that the consumption of red wine may lower the risk of cardiovascular disease. The cardioprotective effect of red wine has been attributed to the polyphenols present in red wine, particularly resveratrol (a stilbene, with estrogen-like activity), and the flavonoids, catechin, epicatechin, quercetin and phenolic acids such as gallic acid. At present, very little is known about the mechanisms by which red wine phenolic compounds benefit the cardiovascular system. Therefore, the aim of this study was to elucidate whether red wine polyphenolics reduce lipoprotein production and clearance by the liver. Cultured HepG2 cells were incubated in the presence of dealcoholized red wine, alcohol-containing red wine and atorvastatin for 24 h. The apolipoprotien B100 (apoB100) protein (marker of hepatic lipoproteins) was quantified on Western blots with an anti-apoB100 antibody and the enhanced chemiluminescence detection system. Apolipoprotein B100 levels in the cells and that secreted into the media were significantly reduced by 50% in liver cells incubated with alcohol-stripped red wine compared with control cells. This effect of dealcoholized red wine on apoB100 production in HepG2 cells was similar to the effect of atorvastatin. Apo B100 production was significantly attenuated by 30% in cells incubated with alcoholized red wine, suggesting that the alcohol was masking the effect of red wine polyphenolics. Apo B100 production was significantly attenuated by 45% with the polyphenolic compounds resveratrol and quercertin. In addition, dealcoholized and alcoholized red wine and atorvastatin significantly increased 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase mRNA and LDL receptor binding activity relative to controls. Dealcoholized red wine also increased LDL receptor gene expression. Collectively, this study suggests that red wine polyphenolics regulate major pathways involved in lipoprotein metabolism. PMID:12612140

  5. Echium oil reduces plasma triglycerides by increasing intravascular lipolysis in apoB100-only low density lipoprotein (LDL) receptor knockout mice.

    PubMed

    Forrest, Lolita M; Lough, Christopher M; Chung, Soonkyu; Boudyguina, Elena Y; Gebre, Abraham K; Smith, Thomas L; Colvin, Perry L; Parks, John S

    2013-07-01

    Echium oil (EO), which is enriched in SDA (18:4 n-3), reduces plasma triglyceride (TG) concentrations in humans and mice. We compared mechanisms by which EO and fish oil (FO) reduce plasma TG concentrations in mildly hypertriglyceridemic male apoB100-only LDLrKO mice. Mice were fed one of three atherogenic diets containing 0.2% cholesterol and palm oil (PO; 20%), EO (10% EO + 10% PO), or FO (10% FO + 10% PO). Livers from PO- and EO-fed mice had similar TG and cholesteryl ester (CE) content, which was significantly higher than in FO-fed mice. Plasma TG secretion was reduced in FO vs. EO-fed mice. Plasma very low density lipoprotein (VLDL) particle size was ordered: PO (63 ± 4 nm) > EO (55 ± 3 nm) > FO (40 ± 2 nm). Post-heparin lipolytic activity was similar among groups, but TG hydrolysis by purified lipoprotein lipase was significantly greater for EO and FO VLDL compared to PO VLDL. Removal of VLDL tracer from plasma was marginally faster in EO vs. PO fed mice. Our results suggest that EO reduces plasma TG primarily through increased intravascular lipolysis of TG and VLDL clearance. Finally, EO may substitute for FO to reduce plasma TG concentrations, but not hepatic steatosis in this mouse model. PMID:23857172

  6. Echium Oil Reduces Plasma Triglycerides by Increasing Intravascular Lipolysis in apoB100-Only Low Density Lipoprotein (LDL) Receptor Knockout Mice

    PubMed Central

    Forrest, Lolita M.; Lough, Christopher M.; Chung, Soonkyu; Boudyguina, Elena Y.; Gebre, Abraham K.; Smith, Thomas L.; Colvin, Perry L.; Parks, John S.

    2013-01-01

    Echium oil (EO), which is enriched in SDA (18:4 n-3), reduces plasma triglyceride (TG) concentrations in humans and mice. We compared mechanisms by which EO and fish oil (FO) reduce plasma TG concentrations in mildly hypertriglyceridemic male apoB100-only LDLrKO mice. Mice were fed one of three atherogenic diets containing 0.2% cholesterol and palm oil (PO; 20%), EO (10% EO + 10% PO), or FO (10% FO + 10% PO). Livers from PO- and EO-fed mice had similar TG and cholesteryl ester (CE) content, which was significantly higher than in FO-fed mice. Plasma TG secretion was reduced in FO vs. EO-fed mice. Plasma very low density lipoprotein (VLDL) particle size was ordered: PO (63 ± 4 nm) > EO (55 ± 3 nm) > FO (40 ± 2 nm). Post-heparin lipolytic activity was similar among groups, but TG hydrolysis by purified lipoprotein lipase was significantly greater for EO and FO VLDL compared to PO VLDL. Removal of VLDL tracer from plasma was marginally faster in EO vs. PO fed mice. Our results suggest that EO reduces plasma TG primarily through increased intravascular lipolysis of TG and VLDL clearance. Finally, EO may substitute for FO to reduce plasma TG concentrations, but not hepatic steatosis in this mouse model. PMID:23857172

  7. Gender-Specific Differences in the Kinetics of Nonfasting TRL, IDL, and LDL Apolipoprotein B-100 in Men and Premenopausal Women

    PubMed Central

    Matthan, Nirupa R.; Jalbert, Susan M.; Barrett, P. Hugh R.; Dolnikowski, Gregory G.; Schaefer, Ernst J.; Lichtenstein, Alice H.

    2010-01-01

    Objective To investigate mechanisms underlying gender differences in serum lipoprotein concentrations, the kinetic behavior of apoB-100 was assessed. Methods and Results Twenty subjects (<50 years; 12 men and 8 premenopausal women) were provided a Western diet for 4 to 6 weeks, after which the kinetics of apoB-100 in triglyceride-rich, intermediate-density, and low-density lipoprotein (TRL, IDL, and LDL) were determined in the fed state. Nonfasting plasma TC, LDL-C, and triglyceride concentrations were 23%, 34%, and 57% lower, respectively, in the women compared with men. Plasma TRL and LDL apoB 100 pool sizes were lower by 40% and 30%, respectively. These differences were accounted for by higher TRL and LDL apoB 100 fractional catabolic rates (FCR), rather than differences in production rates (PR). Plasma TRL-C and LDL-C were positively correlated with TRL and LDL apoB 100 concentrations and pool size, and negatively correlated with TRL and LDL apoB 100 FCR (women: r=−0.59, P<0.01 and r=−0.54, P<0.04, and men: r=−0.43, P<0.05 and r=−0.44, P<0.05). No significant associations were observed between plasma TRL-C and LDL-C and PR. Conclusions These data suggest the mechanism for lower TRL-C and LDL-C concentrations in women was determined predominantly by higher TRL and LDL FCR rather than lower PR. This could explain, in part, the lower CVD risk in premenopausal women relative to men. PMID:18658047

  8. Effect of almond skin polyphenolics and quercetin on human LDL and apolipoprotein B-100 oxidation and conformation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Almond skin flavonoids (ASF) inhibit Cu2+-induced generation of conjugated dienes in low density lipoproteins (LDL). However, the effect of ASF on apolipoprotein B-100 oxidation and LDL conformation has not been explored. ASF (0.12-2.0 µmol/L gallic acid equivalents) were incubated with human LDL an...

  9. The intravenous injection of oxidized LDL- or Apolipoprotein B100 – Coupled splenocytes promotes Th1 polarization in wildtype and Apolipoprotein E – Deficient mice

    SciTech Connect

    Steinmetz, Martin; Ponnuswamy, Padmapriya; Laurans, Ludivine; Esposito, Bruno; Tedgui, Alain; Mallat, Ziad

    2015-08-14

    Background: Th1 responses in atherosclerosis are mainly associated with the aggravation of atherosclerotic plaques, whereas Th2 responses lead to a less pronounced disease in mouse models. The fixation of antigens on cells by means of ethylene carbodiimide (ECDI), and subsequent injection of these antigen-coupled splenocytes (Ag-SP) to induce tolerance against the attached antigens, has been successfully used to treat murine type 1 diabetes or encephalomyelitis in. We analyzed this approach in a mouse model for atherosclerosis. Methods and results: OTII-transgenic mice that were treated with a single dose of 5 × 10{sup 7} OVA-coupled splenocytes (OVA-SP), had decreased splenocyte proliferation, and lower IFNγ production in vitro upon antigen recall. However, in vivo CD4 cell activation was increased. To try lipoprotein-derived, “atherosclerosis-associated” antigens, we first tested human oxidized LDL. In wild type mice, an increase of IFNγ production upon in vitro recall was detected in the oxLDL-SP group. In Apolipoprotein E − deficient (ApoE−/−) mice that received oxLDL-SP every 5 weeks for 20 weeks, we did not find any difference of atherosclerotic plaque burden, but again increased IFNγ production. To overcome xenogenous limitations, we then examined the effects of mouse Apolipoprotein B100 peptides P3 and P6. ApoB100-SP treatment again promoted a more IFNγ pronounced response upon in vitro recall. Flow cytometry analysis of cytokine secreting spleen cells revealed CD4 positive T cells to be mainly the source for IFNγ. In ApoE−/− mice that were administered ApoB100-SP during 20 weeks, the atherosclerotic plaque burden in aortic roots as well as total aorta was unchanged compared to PBS treated controls. Splenocyte proliferation upon antigen recall was not significantly altered in ApoB100-SP treated ApoE−/− mice. Conclusion: Although we did not observe a relevant anti-atherosclerotic benefit, the treatment with antigen

  10. Atheroprotective Vaccination with MHC-II Restricted Peptides from ApoB-100

    PubMed Central

    Tse, Kevin; Gonen, Ayelet; Sidney, John; Ouyang, Hui; Witztum, Joseph L.; Sette, Alessandro; Tse, Harley; Ley, Klaus

    2013-01-01

    Background: Subsets of CD4+ T-cells have been proposed to serve differential roles in the development of atherosclerosis. Some T-cell types are atherogenic (T-helper type 1), while others are thought to be protective (regulatory T-cells). Lineage commitment toward one type of helper T-cell versus another is strongly influenced by the inflammatory context in which antigens are recognized. Immunization of atherosclerosis-prone mice with low-density lipoprotein (LDL) or its oxidized derivative (ox-LDL) is known to be atheroprotective. However, the antigen specificity of the T-cells induced by vaccination and the mechanism of protection are not known. Methods: Identification of two peptide fragments (ApoB3501–3516 and ApoB978–993) from murine ApoB-100 was facilitated using I-Ab prediction models, and their binding to I-Ab determined. Utilizing a vaccination scheme based on complete and incomplete Freund’s adjuvant (CFA and IFA) [1 × CFA + 4 × IFA], we immunized Apoe−/−mice with ApoB3501–3516 or ApoB978–993 emulsified in CFA once and subsequently boosted in IFA four times over 15 weeks. Spleens, lymph nodes, and aortas were harvested and evaluated by flow cytometry and real time RT-PCR. Total atherosclerotic plaque burden was determined by aortic pinning and by aortic root histology. Results: Mice immunized with ApoB3501–3516 or ApoB978–993 demonstrated 40% reduction in overall plaque burden when compared to adjuvant-only control mice. Aortic root frozen sections from ApoB3501–3516 immunized mice showed a >60% reduction in aortic sinus plaque development. Aortas from both ApoB3501–3516 and ApoB978–993 immunized mice contained significantly more mRNA for IL-10. Both antigen-specific IgG1 and IgG2c titers were elevated in ApoB3501–3516 or ApoB978–993 immunized mice, suggesting helper T-cell immune activity after immunization. Conclusion: Our data show that MHC Class II restricted ApoB-100 peptides can be atheroprotective

  11. Gender specific differences in the kinetics of TRL, IDL and LDL apolipoprotein B-100 in men and premenopausal women

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To investigate mechanisms underlying gender differences in serum lipoprotein concentrations, the kinetic behavior of apoB-100 was assessed. Twenty subjects (<50 years; n=12 men and n=8 premenopausal women) were provided a standardized Western diet for 4-6 weeks, at the end of which the kinetics of a...

  12. Homozygous familial hypobetalipoproteinemia. Increased LDL catabolism in hypobetalipoproteinemia due to a truncated apolipoprotein B species, apo B-87Padova.

    PubMed

    Gabelli, C; Bilato, C; Martini, S; Tennyson, G E; Zech, L A; Corsini, A; Albanese, M; Brewer, H B; Crepaldi, G; Baggio, G

    1996-09-01

    Mutations on the apolipoprotein (apo) B gene that interfere with the full-length translation of the apoB molecule are associated with familial hypobetalipoproteinemia (FHBL), a disease characterized by the reduction of plasma apoB and LDL cholesterol. In this report, we describe an FHBL kindred carrying a unique truncated apoB form, apoB-87Padova. Sequence analysis of amplified genomic DNA identified a single G deletion at nucleotide 12032, which shifts the translation reading frame and causes a termination at amino acid 3978. Two homozygous subjects and seven heterozygous relatives were studied. Although homozygous individuals had only trace amounts of LDL, they were virtually free from the symptoms typical of homozygous FHBL subjects. We investigated the in vivo turnover of radiolabeled normal apoB-100 LDL and apoB-87 LDL in one homozygous patient and two normal control subjects. ApoB-87 LDL showed a similar metabolism in all three subjects, with a fractional catabolic rate more than double that of normal LDL. The rate of entry of apoB-87 in the LDL compartment was also markedly decreased compared with normal apoB-100. The increased in vivo catabolism of apoB-87 LDL was paralleled in vitro by a 2.5-fold increased ability of these particles to inhibit the uptake and degradation of normal apoB-100 LDL by normal human cultured fibroblasts. These results indicate that apoB-87 LDL has an enhanced ability to interact with the LDL receptor, the increased apoB catabolism contributes to the hypobetalipoproteinemia and may explain the mild expression of the disease in the two homozygous individuals. PMID:8792774

  13. Human luteinized granulosa cells secrete apoB100-containing lipoproteins.

    PubMed

    Gautier, Thomas; Becker, Steffi; Drouineaud, Véronique; Ménétrier, Franck; Sagot, Paul; Nofer, Jerzy-Roch; von Otte, Sören; Lagrost, Laurent; Masson, David; Tietge, Uwe J F

    2010-08-01

    Thus far, liver, intestine, heart, and placenta have been shown to secrete apolipoprotein (apo)B-containing lipoproteins. In the present study, we first investigated lipoproteins in human follicular fluid (FF), surrounding developing oocytes within the ovary, as well as in corresponding plasma samples (n = 12). HDL cholesterol within FF correlated well with plasma HDL cholesterol (r = 0.80, P < 0.01), whereas VLDL cholesterol did not, indicating that VLDL in FF might originate directly from the granulosa cells producing FF. Primary human granulosa cells expressed apoB, microsomal triglyceride transfer protein, and apoE, but not the apoB-editing enzyme apobec-1. Using (3)H-leucine, we show that granulosa cells secrete apoB100-containing lipoproteins and that secretion can be stimulated by adding oleate to the medium (+83%). With electron microscopy, apoB-containing lipoproteins within the secretory pathway of human granulosa cells were directly visualized. Finally, we found a positive relationship between apoB levels in FF and improved fertility parameters in a population of 27 women undergoing in vitro fertilization. This study demonstrates that human granulosa cells assemble and secrete apoB100-containing lipoproteins, thereby identifying a novel cell type equipped with these properties. These results might have important implications for female infertility phenotypes as well as for the development of drugs targeting the VLDL production pathway. PMID:20407020

  14. Influence of ApoB100 3′ hypervariable repeats on acute myocardial infarction

    PubMed Central

    Singh, Neha; Sinha, Nakul; Kumar, Sudeep; Pandey, Chandra M; Agrawal, Suraksha

    2014-01-01

    Background and objective The 3′ flanking region of apolipoprotein B (ApoB) 100 gene is known to contain short A+T-rich DNA sequences which are hypervariable in nature and called the variable number of tandem repeats (VNTRs). It results in different alleles of ApoB100. The present study extends the investigation of whether there is a correlation between the presence of these alleles and acute myocardial infarction (MI). Methods We examined ApoB genotypes in 230 acute MI patients and 300 healthy controls. PCR based genotyping was done for ApoB 3′ VNTRs. Results We recoded 3′ApoB-VNTR alleles through three- and five-allelic models based on different sizes and found that large repeats (>37) were significantly associated with acute MI (p<0.0001). These large repeats (>37) were also significantly associated with higher lipid levels in the MI group. Conclusion Patients with 3′ApoB-VNTR large repeats (>37) are more susceptible to acute MI development.

  15. Different fatty acids inhibit apoB100 secretion by different pathways: unique roles for ER stress, ceramide, and autophagy

    PubMed Central

    Caviglia, Jorge Matias; Gayet, Constance; Ota, Tsuguhito; Hernandez-Ono, Antonio; Conlon, Donna M.; Jiang, Hongfeng; Fisher, Edward A.; Ginsberg, Henry N.

    2011-01-01

    Although short-term incubation of hepatocytes with oleic acid (OA) stimulates secretion of apolipoprotein B100 (apoB100), exposure to higher doses of OA for longer periods inhibits secretion in association with induction of endoplasmic reticulum (ER) stress. Palmitic acid (PA) induces ER stress, but its effects on apoB100 secretion are unclear. Docosahexaenoic acid (DHA) inhibits apoB100 secretion, but its effects on ER stress have not been studied. We compared the effects of each of these fatty acids on ER stress and apoB100 secretion in McArdle RH7777 (McA) cells: OA and PA induced ER stress and inhibited apoB100 secretion at higher doses; PA was more potent because it also increased the synthesis of ceramide. DHA did not induce ER stress but was the most potent inhibitor of apoB100 secretion, acting via stimulation of autophagy. These unique effects of each fatty acid were confirmed when they were infused into C57BL6J mice. Our results suggest that when both increased hepatic secretion of VLDL apoB100 and hepatic steatosis coexist, reducing ER stress might alleviate hepatic steatosis but at the expense of increased VLDL secretion. In contrast, increasing autophagy might reduce VLDL secretion without causing steatosis. PMID:21719579

  16. Gender and age specific differences in the kinetic behavior of TRL, IDL and LDL apolipoprotein B-100 and HDL apolipoprotein A-I

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gender specific differences in lipid and lipoprotein profile, predominantly higher LDL-C, VLDL-C and TG, and lower HDL-C levels have been observed in males compared to females. These differences are influenced by menopausal status and age. To investigate mechanism(s) involved, apolipoprotein (apo) B...

  17. Acidity and lipolysis by group V secreted phospholipase A(2) strongly increase the binding of apoB-100-containing lipoproteins to human aortic proteoglycans.

    PubMed

    Lähdesmäki, Katariina; Öörni, Katariina; Alanne-Kinnunen, Mervi; Jauhiainen, Matti; Hurt-Camejo, Eva; Kovanen, Petri T

    2012-02-01

    Local acidic areas characterize diffuse intimal thickening (DIT) and advanced atherosclerotic lesions. The role of acidity in the modification and extra- and intracellular accumulation of triglyceride-rich VLDL and IDL particles has not been studied before. Here, we examined the effects of acidic pH on the activity of recombinant human group V secreted phospholipase A(2) (sPLA(2)-V) toward small VLDL (sVLDL), IDL, and LDL, on the binding of these apoB-100-containing lipoproteins to human aortic proteoglycans, and on their uptake by human monocyte-derived macrophages. At acidic pH, the ability of sPLA(2)-V to lipolyze the apoB-100-containing lipoproteins was moderately, but significantly, increased while binding of the lipoproteins to proteoglycans increased >60-fold and sPLA(2)-V-modification further doubled the binding. Moreover, acidic pH more than doubled macrophage uptake of soluble complexes of sPLA(2)-V-LDL with aortic proteoglycans. Proteoglycan-affinity chromatography at pH 7.5 and 5.5 revealed that sVLDL, IDL, and LDL consisted of populations with different proteoglycan-binding affinities, and, surprisingly, the sVLDL fractions with the highest proteoglycan-affinity contained only low amounts of apolipoproteins E and C-III. Our results suggest that in atherosclerotic lesions with acidic extracellular pH, sPLA(2)-V is able to lipolyze sVLDL, IDL, and LDL, and increase their binding to proteoglycans. This is likely to provoke extracellular accumulation of lipids derived from these atherogenic lipoprotein particles and to increase the progression of the atherosclerotic lesions. PMID:22041135

  18. Echium Oil Reduces Atherosclerosis in apoB100-only LDLrKO Mice

    PubMed Central

    Forrest, Lolita M.; Boudyguina, Elena; Wilson, Martha D.; Parks, John S.

    2012-01-01

    Introduction The anti-atherogenic and hypotriglyceridemic properties of fish oil are attributed to its enrichment in eicosapentaenoic acid (EPA; 20:5, n-3) and docosahexaenoic acid (DHA; 22:6, n-3). Echium oil contains stearidonic acid (SDA; 18:4, n-3), which is metabolized to EPA in humans and mice, resulting in decreased plasma triglycerides. Objective We used apoB100 only, LDLrKO mice to investigate whether echium oil reduces atherosclerosis. Methods Mice were fed palm, echium, or fish oil-containing diets for 16 weeks and plasma lipids, lipoproteins, and atherosclerosis were measured. Results Compared to palm oil, echium oil feeding resulted in significantly less plasma triglyceride and cholesterol levels, and atherosclerosis, comparable to that of fish oil. Conclusion This is the first report that echium oil is anti-atherogenic, suggesting that it may be a botanical alternative to fish oil for atheroprotection. PMID:22100249

  19. Influence of peroxisome proliferator-activated receptor alpha agonists on the intracellular turnover and secretion of apolipoprotein (Apo) B-100 and ApoB-48.

    PubMed

    Lindén, Daniel; Lindberg, Karin; Oscarsson, Jan; Claesson, Catharina; Asp, Lennart; Li, Lu; Gustafsson, Maria; Borén, Jan; Olofsson, Sven-Olof

    2002-06-21

    The peroxisome proliferator-activated receptor (PPAR) alpha agonist WY 14,643 increased the secretion of apolipoprotein (apo) B-100, but not that of apoB-48, and decreased triglyceride biosynthesis and secretion from primary rat hepatocytes. These effects resulted in decreased secretion of apoB-100-very low density lipoprotein (VLDL) and an increased secretion of apoB-100 on low density lipoproteins/intermediate density lipoproteins. ApoB-48-VLDL was also replaced by more dense particles. The proteasomal inhibitor lactacystin did not influence the recovery of apoB-100 or apoB-48 in primary rat hepatocytes, indicating that co-translational (proteasomal) degradation is of less importance in these cells. Treatment with WY 14,643 made the recovery of apoB-100 sensitive to lactacystin, most likely reflecting the decreased biosynthesis of triglycerides. The PPAR alpha agonist induced a significant increase in the accumulation of pulse-labeled apoB-100 even after a short pulse (2-5 min). There was also an increase in apoB-100 nascent polypeptides, indicating that the co-translational degradation of apoB-100 was inhibited. However, a minor influence on an early posttranslation degradation cannot be excluded. This decreased co-translational degradation of apoB-100 explained the increased secretion of the protein. The levels of apoB-48 remained unchanged during these pulse-chase experiments, and albumin production was not affected, indicating a specific effect of PPAR alpha agonists on the co-translational degradation of apoB-100. These findings explain the difference in the rate of secretion of the two apoB proteins seen after PPAR alpha activation. PPAR alpha agonists increased the expression and biosynthesis of liver fatty acid-binding protein (LFABP). Increased expression of LFABP by transfection of McA-RH7777 cells increased the secretion of apoB-100, decreased triglyceride biosynthesis and secretion, and increased PPAR alpha mRNA levels. These findings suggest that

  20. Uptake of 68gallium in atherosclerotic plaques in LDLR-/-ApoB100/100 mice

    PubMed Central

    2011-01-01

    Background Atherosclerosis is a chronic inflammatory disease of artery wall characterized by infiltration of monocytes into subendothelial space and their differentiation into macrophages. Since rupture-prone plaques commonly contain high amounts of activated macrophages, imaging of the macrophage content may provide a useful tool for the evaluation of plaque vulnerability. The purpose of this study was to explore the uptake of 68gallium (68Ga) in atherosclerotic plaques in mice. Methods Uptake of ionic 68Ga was investigated in atherosclerotic LDLR-/-ApoB100/100 and C57BL/6N control mice at 3 h after injection. The ex vivo biodistribution of the 68Ga was assessed and autoradiography of aortic cryosections was defined. In vivo imaging of 68Ga was performed using a small animal positron emission tomography PET/CT scanner. Results Our results revealed that the uptake of 68Ga-radioactivity was higher in atherosclerotic plaques than in healthy vessel wall (ratio 1.8 ± 0.2, p = 0.0002) and adventitia (ratio 1.3 ± 0.2, p = 0.0011). The autoradiography signal co-localized with macrophages prominently as demonstrated by Mac-3 staining. In both mice strains, the highest level of radioactivity was found in the blood. Conclusions We observed a moderate but significantly elevated 68Ga-radioactivity uptake in the aortic plaques of atherosclerotic mice, especially at the sites rich in macrophages. While the uptake of 68Ga was promising in this animal model, the slow blood clearance may limit the usability of 68Ga as a PET tracer for clinical imaging of atherosclerotic plaques. PMID:22214258

  1. In vitro oxidative footprinting provides insight into apolipoprotein B-100 structure in low density lipoprotein

    PubMed Central

    Chakraborty, Sourav; Cai, Yang; Tarr, Matthew A.

    2015-01-01

    Low density lipoprotein (LDL) is a major cholesterol carrier in human blood. Oxidations of apolipoprotein B-100 (apo B-100, LDL protein) could be pro-atherogenic and play critical roles in early stages of plaque formation in the arterial wall. The structure of apo B-100 is still poorly understood, partially due to its size (550 KDa, 4563 amino acids). To gain an insight into LDL structure, we mapped the regions of apo B-100 in human LDL which were prone to oxidation using peroxynitrite and hypochlorite as probes. In this study, LDL was incubated with various concentrations of peroxynitrite and sodium hypochlorite in bicarbonate buffer. The LDL protein apo B-100 was delipidated, denatured, alkylated and subjected to tryptic digestion. Tryptic peptides were analyzed employing liquid chromatography – tandem mass spectrometry (LC-MS/MS). Database search was performed against the apo B-100 database (P04114) using “SEQUEST” algorithm to identify peroxynitrite and hypochlorite mediated oxidations markers nitrotyrosine, nitrotryptophan, hydroxy-tryptophan and 3-chlorotyrosine. Several site specific oxidations were identified in apo B-100 after treatment of intact LDL particles with the oxidants. We hypothesize that these regions could be accessible to oxidant and critical for early events in atherosclerotic plaque deposition. PMID:25176030

  2. Mice That Produce ApoB100 Lipoproteins in the RPE Do Not Develop Drusen yet Are Still a Valuable Experimental System

    PubMed Central

    Fujihara, Masashi; Cano, Marisol; Handa, James T.

    2014-01-01

    Purpose. Mice typically produce apolipoprotein B (apoB)-48 and not apoB100. Apolipoprotein B100 accumulates in Bruch's membrane prior to basal deposit and drusen formation during the onset of AMD, raising the possibility that they are a trigger for these Bruch's membrane alterations. The purpose herein, was to determine whether mice that predominantly produce apoB100 develop features of AMD. Methods. The eyes of mice that produce apoB100 were examined for apoB100 synthesis, cholesteryl esterase/filipin labeling for cholesteryl esters, and transmission electron microscopy for lipid particles and phenotype. Results. Apolipoprotein B100 was abundant in the RPE-choroid of apoB100, but not wild-type mice by Western blot analysis. The apolipoprotein B100,35S-radiolabeled and immunoprecipitated from RPE explants, confirmed that apoB100 was synthesized by RPE. Apolipoprotein B100, but not control mice, had cholesteryl esters and lipid particles in Bruch's membrane. Immunoreactivity of ApoB100 was present in the RPE and Bruch's membrane, but not choroidal endothelium of apoB100 mice. Ultrastructural changes were consistent with aging, but not AMD when aged up to 18 months. The induction of advanced glycation end products to alter Bruch's membrane, did not promote basal linear deposit or drusen formation. Conclusions. Mice that produce apoB100 in the RPE and liver secrete lipoproteins into Bruch's membrane, but not to the extent that distinct features of AMD develop, which suggests that either additional lipoprotein accumulation or additional factors are necessary to initiate their formation. PMID:25316721

  3. Immunochemical Analysis of the Electronegative LDL Subfraction Shows That Abnormal N-terminal Apolipoprotein B Conformation Is Involved in Increased Binding to Proteoglycans*

    PubMed Central

    Bancells, Cristina; Benítez, Sònia; Ordóñez-Llanos, Jordi; Öörni, Katariina; Kovanen, Petri T.; Milne, Ross W.; Sánchez-Quesada, José L.

    2011-01-01

    Electronegative LDL (LDL(−)) is a minor subfraction of modified LDL present in plasma. Among its atherogenic characteristics, low affinity to the LDL receptor and high binding to arterial proteoglycans (PGs) could be related to abnormalities in the conformation of its main protein, apolipoprotein B-100 (apoB-100). In the current study, we have performed an immunochemical analysis using monoclonal antibody (mAb) probes to analyze the conformation of apoB-100 in LDL(−). The study, performed with 28 anti-apoB-100 mAbs, showed that major differences of apoB-100 immunoreactivity between native LDL and LDL(−) concentrate in both terminal extremes. The mAbs Bsol 10, Bsol 14 (which recognize the amino-terminal region), Bsol 2, and Bsol 7 (carboxyl-terminal region) showed increased immunoreactivity in LDL(−), suggesting that both terminal extremes are more accessible in LDL(−) than in native LDL. The analysis of in vitro-modified LDLs, including LDL lipolyzed with sphingomyelinase (SMase-LDL) or phospholipase A2 (PLA2-LDL) and oxidized LDL (oxLDL), suggested that increased amino-terminal immunoreactivity was related to altered conformation due to aggregation. This was confirmed when the aggregated subfractions of LDL(−) (agLDL(−)) and oxLDL (ag-oxLDL) were isolated and analyzed. Thus, Bsol 10 and Bsol 14 immunoreactivity was high in SMase-LDL, ag-oxLDL, and agLDL(−). The altered amino-terminal apoB-100 conformation was involved in the increased PG binding affinity of agLDL(−) because Bsol 10 and Bsol 14 blocked its high PG-binding. These observations suggest that an abnormal conformation of the amino-terminal region of apoB-100 is responsible for the increased PG binding affinity of agLDL(−). PMID:21078674

  4. Apolipoprotein B-100 Hopkins (arginine sub 4019 yields tryptophan): A new apolipoprotein B-100 variant in a family with premature atherosclerosis and hyperapobetalipoproteinemia

    SciTech Connect

    Ladias, J.A.A.; Kwiterovich, P.O. Jr.; Smith, H.H.; Miller, M.; Bachorik, P.S.; Antonarakis, S.E. ); Forte, T. ); Lusis, A.J. )

    1989-10-13

    A 43-year-old woman with severe coronary artery disease and hyperapobetalipoproteinemia was heterozygous for an abnormal Msp I apolipoprotein B (APOB) gene fragment because of the absence of the Msp I site around codon 4046 in exon 29 of the APOB gene. Using the polymerase chain reaction technique, 134 base pairs containing the mutant Msp I site were amplified, cloned, and sequenced. The mutation was a C to T transition, substituting tryptophan for arginine at amino acid position 4019 of the mature ApoB-100 protein. Seven relatives of the proband has the same mutation, which has been called ApoB-100 Hopkins. Only three of seven relatives with the mutation had hyperapobetalipoproteinemia. Mutant low-density lipoprotein (LDL) was bound and degraded to a greater extent than normal LDL in cultured human fibroblasts. In conclusion, a new mutation, ApoB-100 Hopkins, was not linked to the hyperapobetalipoproteinemia phenotype, which also was segregating in this family. The increased affinity of this mutant LDL for the LDL receptor may be due to a specific effect of ApoB-100 Hopkins or to altered LDL size and composition.

  5. Mechanisms responsible for hepatic very low density lipoprotein-apoB100 overproduction in Otsuka Long-Evans Tokushima fatty rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Overproduction of hepatic very low-density lipoprotein (VLDL)1 particles is a major abnormality of lipoprotein dysregulation in type 2 diabetes (T2D). We sought to examine the mechanisms linking systemic/hepatic inflammation associated with insulin resistance and apolipoprotein (apo) B100-containing...

  6. LDL-apheresis depletes apoE-HDL and pre-β1-HDL in familial hypercholesterolemia: relevance to atheroprotection

    PubMed Central

    Orsoni, Alexina; Saheb, Samir; Levels, Johannes H. M.; Dallinga-Thie, Geesje; Atassi, Marielle; Bittar, Randa; Robillard, Paul; Bruckert, Eric; Kontush, Anatol; Carrié, Alain; Chapman, M. John

    2011-01-01

    Subnormal HDL-cholesterol (HDL-C) and apolipoprotein (apo)AI levels are characteristic of familial hypercholesterolemia (FH), reflecting perturbed intravascular metabolism with compositional anomalies in HDL particles, including apoE enrichment. Does LDL-apheresis, which reduces HDL-cholesterol, apoAI, and apoE by adsorption, induce selective changes in HDL subpopulations, with relevance to atheroprotection? Five HDL subpopulations were fractionated from pre- and post-LDL-apheresis plasmas of normotriglyceridemic FH subjects (n = 11) on regular LDL-apheresis (>2 years). Apheresis lowered both plasma apoE (−62%) and apoAI (−16%) levels, with preferential, genotype-independent reduction in apoE. The mass ratio of HDL2:HDL3 was lowered from ∼1:1 to 0.72:1 by apheresis, reflecting selective removal of HDL2 mass (80% of total HDL adsorbed). Pre-LDL-apheresis, HDL2 subpopulations were markedly enriched in apoE, consistent with ∼1 copy of apoE per 4 HDL particles. Large amounts (50-66%) of apoE-HDL were removed by apheresis, preferentially in the HDL2b subfraction (−50%); minor absolute amounts of apoE-HDL were removed from HDL3 subfractions. Furthermore, pre-β1-HDL particle levels were subnormal following removal (−53%) upon apheresis, suggesting that cellular cholesterol efflux may be defective in the immediate postapheresis period. In LDL-receptor (LDL-R) deficiency, LDL-apheresis may enhance flux through the reverse cholesterol transport pathway and equally attenuate potential biglycan-mediated deposition of apoE-HDL in the arterial matrix. PMID:21957200

  7. Identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein B100.

    PubMed

    Wang, Shiyu; Park, Shuin; Kodali, Vamsi K; Han, Jaeseok; Yip, Theresa; Chen, Zhouji; Davidson, Nicholas O; Kaufman, Randal J

    2015-02-15

    Apolipoprotein (apo) B is an obligatory component of very low density lipoprotein (VLDL), and its cotranslational and posttranslational modifications are important in VLDL synthesis, secretion, and hepatic lipid homeostasis. ApoB100 contains 25 cysteine residues and eight disulfide bonds. Although these disulfide bonds were suggested to be important in maintaining apoB100 function, neither the specific oxidoreductase involved nor the direct role of these disulfide bonds in apoB100-lipidation is known. Here we used RNA knockdown to evaluate both MTP-dependent and -independent roles of PDI1 in apoB100 synthesis and lipidation in McA-RH7777 cells. Pdi1 knockdown did not elicit any discernible detrimental effect under normal, unstressed conditions. However, it decreased apoB100 synthesis with attenuated MTP activity, delayed apoB100 oxidative folding, and reduced apoB100 lipidation, leading to defective VLDL secretion. The oxidative folding-impaired apoB100 was secreted mainly associated with LDL instead of VLDL particles from PDI1-deficient cells, a phenotype that was fully rescued by overexpression of wild-type but not a catalytically inactive PDI1 that fully restored MTP activity. Further, we demonstrate that PDI1 directly interacts with apoB100 via its redox-active CXXC motifs and assists in the oxidative folding of apoB100. Taken together, these findings reveal an unsuspected, yet key role for PDI1 in oxidative folding of apoB100 and VLDL assembly. PMID:25518935

  8. Atherosclerosis, inflammation and lipoprotein glomerulopathy in kidneys of apoE-/-/LDL-/- double knockout mice

    PubMed Central

    2010-01-01

    Background The apoE-/-/LDL-/- double knockout mice are bearing considerable structural homology to human atherosclerosis. We hypothesized, that advanced lesion formation in the renal artery is associated with kidney alterations in these mice. Methods Kidneys from apoE-/-/LDL-/- double knockout mice at the age of 80 weeks (n = 6) and C57/BL control mice (n = 5) were infused with Microfil, harvested and scanned with micro-CT (12 μm cubic voxels) and Nano-CT (900 nm cubic voxels). We quantitated the total vascular volume using micro-CT. Number and cross-sectional area (μm2) of glomeruli were measured using histology. Results At the age of 80 weeks, the renal total vascular volume fraction decreased significantly (p < 0.001) compared to controls. Moreover, the renal artery showed advanced atherosclerotic lesions with adventitial Vasa vasorum neovascularization. Perivascular inflammation was present in kidneys of apoE-/-/LDL-/- double knockout mice, predominantly involved are plasma cells and leucocytes. Glomeruli cross-sectional area (9959 ± 1083 μm2) and number (24.8 ± 4.5) increased in apoE-/-/LDL-/- double knockout mice compared to controls (3533 ± 398 μm2; 17.6 ± 3, respectively), whereas 41% of the total number of glomeruli showed evidence for lipoprotein associated glomerulopathy (LPG). Moreover, immunohistochemistry demonstrated capillary aneurysms of the glomeruli filled with factor 8 containing emboli. Conclusion The reduced intra-renal total vascular volume is associated with systemic atherosclerosis and glomeruli alterations in the apoE-/-/LDL-/- double knockout mouse model. PMID:20727187

  9. Immunization with an ApoB-100 Related Peptide Vaccine Attenuates Angiotensin-II Induced Hypertension and Renal Fibrosis in Mice

    PubMed Central

    Honjo, Tomoyuki; Chyu, Kuang-Yuh; Dimayuga, Paul C.; Lio, Wai Man; Yano, Juliana; Trinidad, Portia; Zhao, Xiaoning; Zhou, Jianchang; Cercek, Bojan; Shah, Prediman K.

    2015-01-01

    Recent studies suggest the potential involvement of CD8+ T cells in the pathogenesis of murine hypertension. We recently reported that immunization with apoB-100 related peptide, p210, modified CD8+ T cell function in angiotensin II (AngII)-infused apoE (-/-) mice. In this study, we hypothesized that p210 vaccine modulates blood pressure in AngII-infused apoE (-/-) mice. Male apoE (-/-) mice were immunized with p210 vaccine and compared to unimmunized controls. At 10 weeks of age, mice were subcutaneously implanted with an osmotic pump which released AngII for 4 weeks. At 13 weeks of age, p210 immunized mice showed significantly lower blood pressure response to AngII compared to controls. CD8+ T cells from p210 immunized mice displayed a different phenotype compared to CD8+ T cells from unimmunized controls. Serum creatinine and urine albumin to creatinine ratio were significantly decreased in p210 immunized mice suggesting that p210 vaccine had renal protective effect. At euthanasia, inflammatory genes IL-6, TNF-α, and MCP-1 in renal tissue were down-regulated by p210 vaccine. Renal fibrosis and pro-fibrotic gene expression were also significantly reduced in p210 immunized mice. To assess the role of CD8+ T cells in these beneficial effects of p210 vaccine, CD8+ T cells were depleted by CD8 depleting antibody in p210 immunized mice. p210 immunized mice with CD8+ T cell depletion developed higher blood pressure compared to mice receiving isotype control. Depletion of CD8+ T cells also increased renal fibrotic gene expression compared to controls. We conclude that immunization with p210 vaccine attenuated AngII-induced hypertension and renal fibrosis. CD8+ T cells modulated by p210 vaccine could play an important role in the anti-hypertensive, anti-fibrotic and renal-protective effect of p210 vaccine. PMID:26121471

  10. Apolipoprotein A-I mimetic peptide 4F blocks sphingomyelinase-induced LDL aggregation[S

    PubMed Central

    Nguyen, Su Duy; Javanainen, Matti; Rissanen, Sami; Zhao, Hongxia; Huusko, Jenni; Kivelä, Annukka M.; Ylä-Herttuala, Seppo; Navab, Mohamad; Fogelman, Alan M.; Vattulainen, Ilpo; Kovanen, Petri T.; Öörni, Katariina

    2015-01-01

    Lipolytic modification of LDL particles by SMase generates LDL aggregates with a strong affinity for human arterial proteoglycans and may so enhance LDL retention in the arterial wall. Here, we evaluated the effects of apoA-I mimetic peptide 4F on structural and functional properties of the SMase-modified LDL particles. LDL particles with and without 4F were incubated with SMase, after which their aggregation, structure, and proteoglycan binding were analyzed. At a molar ratio of L-4F to apoB-100 of 2.5 to 20:1, 4F dose-dependently inhibited SMase-induced LDL aggregation. At a molar ratio of 20:1, SMase-induced aggregation was fully blocked. Binding of 4F to LDL particles inhibited SMase-induced hydrolysis of LDL by 10% and prevented SMase-induced LDL aggregation. In addition, the binding of the SMase-modified LDL particles to human aortic proteoglycans was dose-dependently inhibited by pretreating LDL with 4F. The 4F stabilized apoB-100 conformation and inhibited SMase-induced conformational changes of apoB-100. Molecular dynamic simulations showed that upon binding to protein-free LDL surface, 4F locally alters membrane order and fluidity and induces structural changes to the lipid layer. Collectively, 4F stabilizes LDL particles by preventing the SMase-induced conformational changes in apoB-100 and so blocks SMase-induced LDL aggregation and the resulting increase in LDL retention. PMID:25861792

  11. Coincubation of PON1, APO A1, and LCAT increases the time HDL is able to prevent LDL oxidation.

    PubMed

    Hine, David; Mackness, Bharti; Mackness, Mike

    2012-02-01

    The inhibition of low-density lipoprotein (LDL) oxidation by high-density lipoprotein (HDL) is a major antiatherogenic property of this lipoprotein. This activity is due, in part, to HDL associated proteins. However, whether these proteins interact in the antioxidant activity of HDL is unknown. LDL was incubated with apolipoprotein A1 (apo A1), lecithin:cholesterol acyltransferase (LCAT), and paraoxonase-1 (PON1) alone or in combination, in the presence or absence of HDL under oxidizing conditions. LDL lipid peroxide concentrations were determined. Apo A1, LCAT, and PON1 all inhibit LDL oxidation in the absence of HDL and enhance the ability of HDL to inhibit LDL oxidation. Their effect was additive rather than synergistic; the combination of these proteins significantly enhanced the length of time LDL was protected from oxidation. This seemed to be due to the ability of PON1 to prevent the oxidative inactivation of LCAT. Apo A1, LCAT, and PON1 can all contribute to the antioxidant activity of HDL in vitro. The combination of apo A1, LCAT, and PON1 prolongs the time that HDL can prevent LDL oxidation, due, at least in part, to the prevention LCAT inactivation. PMID:22184096

  12. Insulin decreases the secretion of apoB-100 from hepatic HepG2 cells but does not decrease the secretion of apoB-48 from intestinal CaCo-2 cells.

    PubMed

    Allister, Emma M; Pal, Sebely; Thomson, Andrew M; Helmerhorst, Erik; Mamo, John C L

    2004-01-01

    We compared the acute effect of insulin on the human colonic intestinal epithelial cell line CaCo-2 and the transformed human hepatic cell line HepG2. Over 24 h, 100 nM and 10 microM insulin significantly inhibited the secretion of apolipoprotein (apo) B-100 from HepG2 cells to 63 and 49% of control, respectively. Insulin had no effect on the secretion of apoB-48 from CaCo-2 cells. There was no effect of insulin on the cholesterol ester or free cholesterol concentrations in HepG2 or CaCo-2 cells. HepG2 and CaCo-2 cells bound insulin with high affinity, leading to similar stimulation of insulin receptor protein tyrosine kinase activation. Protein kinase C or mitogen-activated protein kinase activity in the presence or absence of insulin was not correlated with apoB-48 production in CaCo-2 cells. Therefore, insulin acutely decreases the secretion of apoB-100 in hepatic HepG2 cells, but does not acutely modulate the production or secretion of apoB-48 from CaCo-2 intestinal cells. PMID:15591776

  13. Three-Dimensional cryoEM Reconstruction of Native LDL Particles to 16Å Resolution at Physiological Body Temperature

    PubMed Central

    Kumar, Vibhor; Butcher, Sarah J.; Öörni, Katariina; Engelhardt, Peter; Heikkonen, Jukka; Kaski, Kimmo; Ala-Korpela, Mika; Kovanen, Petri T.

    2011-01-01

    Background Low-density lipoprotein (LDL) particles, the major carriers of cholesterol in the human circulation, have a key role in cholesterol physiology and in the development of atherosclerosis. The most prominent structural components in LDL are the core-forming cholesteryl esters (CE) and the particle-encircling single copy of a huge, non-exchangeable protein, the apolipoprotein B-100 (apoB-100). The shape of native LDL particles and the conformation of native apoB-100 on the particles remain incompletely characterized at the physiological human body temperature (37°C). Methodology/Principal Findings To study native LDL particles, we applied cryo-electron microscopy to calculate 3D reconstructions of LDL particles in their hydrated state. Images of the particles vitrified at 6°C and 37°C resulted in reconstructions at ∼16 Å resolution at both temperatures. 3D variance map analysis revealed rigid and flexible domains of lipids and apoB-100 at both temperatures. The reconstructions showed less variability at 6°C than at 37°C, which reflected increased order of the core CE molecules, rather than decreased mobility of the apoB-100. Compact molecular packing of the core and order in a lipid-binding domain of apoB-100 were observed at 6°C, but not at 37°C. At 37°C we were able to highlight features in the LDL particles that are not clearly separable in 3D maps at 6°C. Segmentation of apoB-100 density, fitting of lipovitellin X-ray structure, and antibody mapping, jointly revealed the approximate locations of the individual domains of apoB-100 on the surface of native LDL particles. Conclusions/Significance Our study provides molecular background for further understanding of the link between structure and function of native LDL particles at physiological body temperature. PMID:21573056

  14. Absence of an effect of vitamin E on protein and lipid radical formation during lipoperoxidation of LDL by lipoxygenase

    PubMed Central

    Ganini, Douglas; Mason, Ronald P.

    2014-01-01

    LDL oxidation is the primary event in atherosclerosis, where LDL lipoperoxidation leads to modifications in the apolipoprotein B-100 (apo B-100) and lipids. Intermediate species of lipoperoxidation are known to be able to generate amino acid-centered radicals. Thus, we hypothesized that lipoperoxidation intermediates induce protein-derived free radical formation during LDL oxidation. Using DMPO and immuno spin-trapping, we detected the formation of protein free radicals on LDL incubated with Cu2+ or the soybean lipoxidase (LPOx)/phospholipase A2 (PLA2). With low concentrations of DMPO (1 mM), Cu2+ dose-dependently induced oxidation of LDL and easily detected apo B-100 radicals. Protein radical formation in LDL incubated with Cu2+ showed maximum yields after 30 minutes. In contrast, the yields of apo B-100-radicals formed by LPOx/PLA2 followed a typical enzyme-catalyzed kinetics that was unaffected by DMPO concentrations of up to 50 mM. Furthermore, when we analyzed the effect of antioxidants on protein radical formation during LDL oxidation, we found that ascorbate, urate and Trolox dose-dependently reduced apo B-100-free radical formation in LDL exposed to Cu2+. In contrast, Trolox was the only antioxidant that even partially protected LDL from LPOx/PLA2. We also examined the kinetics of lipid radical formation and protein radical formation induced by Cu2+ or LPOx/PLA2 for LDL supplemented with α-tocopherol. In contrast to the potent antioxidant effect of α-tocopherol on the delay of LDL oxidation induced by Cu2+, when we used the oxidizing system LPOx/PLA2, no significant protection was detected. The lack of protection of α-tocopherol on the apo B-100 and lipid free radical formation by LPOx may explain the failure of vitamin E as a cardiovascular protective agent for humans. PMID:25091900

  15. Chemical sympathectomy induces arterial accumulation of native and oxidized LDL in hypercholesterolemic rats.

    PubMed

    Hachani, Rafik; Dab, Houcine; Sakly, Mohsen; Vicaut, Eric; Callebert, Jacques; Sercombe, Richard; Kacem, Kamel

    2012-01-26

    The aim of the present study was to examine the effect of sympathectomy on plasmatic and arterial native and oxLDL levels, as well as arterial LDL receptors (LDLR) and scavenger receptors in hypercholesterolemic rats, which are normally protected against atherosclerosis. Neonatal Wistar rats received subcutaneous injections of either guanethidine for sympathectomy (Gua+HC) or vehicle (HC), then were fed 1% cholesterol for three months. Intact normocholesterolemic rats were used as control of the HC group. Total cholesterol (TC) and LDL-cholesterol were evaluated in the plasma and the abdominal aorta by an auto-analyzer. Plasmatic and aortic oxLDL and native LDL-apo B100 were assessed by a sandwich ELISA. Aortic and hepatic native LDLR and aortic scavenger receptors (CD36 and SR-A) were quantified at mRNA and protein levels by real time PCR and western immunoblot. The effect of hypercholesterolemia was limited to an increase in plasmatic TC and LDL-cholesterol and a decrease in aortic apoB100 and aortic and hepatic LDLR. Hypercholesterolemia and sympathectomy in combination increased markedly plasmatic and aortic TC, LDL-cholesterol, apo B100 and oxLDL together with aortic scavenger receptors, but reduced markedly aortic and hepatic LDLR. Sympathectomy broke down the rat's protection against hypercholesterolemia by promoting accumulation of native and oxLDL in the aorta via scavenger receptors. PMID:21917529

  16. Genetic Contribution of Variants near SORT1 and APOE on LDL Cholesterol Independent of Obesity in Children

    PubMed Central

    Büttner, Petra; Weise, Sebastian; Schleinitz, Dorit; Kiess, Wieland; Scholz, Markus; Kovacs, Peter; Körner, Antje

    2015-01-01

    Objective To assess potential effects of variants in six lipid modulating genes (SORT1, HMGCR, MLXIPL, FADS2, APOE and MAFB) on early development of dyslipidemia independent of the degree of obesity in children, we investigated their association with total (TC), low density lipoprotein (LDL-C), high density lipoprotein (HDL-C) cholesterol and triglyceride (TG) levels in 594 children. Furthermore, we evaluated the expression profile of the candidate genes during human adipocyte differentiation. Results Expression of selected genes increased 101 to >104 fold during human adipocyte differentiation, suggesting a potential link with adipogenesis. In genetic association studies adjusted for age, BMI SDS and sex, we identified significant associations for rs599839 near SORT1 with TC and LDL-C and for rs4420638 near APOE with TC and LDL-C. We performed Bayesian modelling of the combined lipid phenotype of HDL-C, LDL-C and TG to identify potentially causal polygenic effects on this multi-dimensional phenotype and considering obesity, age and sex as a-priori modulating factors. This analysis confirmed that rs599839 and rs4420638 affect LDL-C. Conclusion We show that lipid modulating genes are dynamically regulated during adipogenesis and that variants near SORT1 and APOE influence lipid levels independent of obesity in children. Bayesian modelling suggests causal effects of these variants. PMID:26375028

  17. Inducible Apoe Gene Repair in Hypomorphic ApoE Mice Deficient in the LDL Receptor Promotes Atheroma Stabilization with a Human-like Lipoprotein Profile

    PubMed Central

    Eberlé, Delphine; Luk, Fu Sang; Kim, Roy Y.; Olivas, Victor R.; Kumar, Nikit; Posada, Jessica M.; Li, Kang; Gaudreault, Nathalie; Rapp, Joseph H.; Raffai, Robert L.

    2013-01-01

    Objective To study atherosclerosis regression in mice following plasma lipid reduction to moderately elevated apolipoprotein B (apoB)-lipoprotein levels. Approach and Results Chow-fed hypomorphic Apoe mice deficient in LDL receptor expression (Apoeh/hLdlr−/−Mx1-cre mice) develop hyperlipidemia and atherosclerosis. These mice were studied before and after inducible cre-mediated Apoe gene repair. By 1 week, induced mice displayed a 2-fold reduction in plasma cholesterol and triglyceride levels and a decrease in the non-HDL:HDL-cholesterol ratio from 87%:13% to 60%:40%. This halted atherosclerotic lesion growth and promoted macrophage loss and accumulation of thick collagen fibers for up to 8 weeks. Concomitantly, blood Ly-6Chi monocytes were decreased by 2-fold but lesional macrophage apoptosis was unchanged. The expression of several genes involved in extra-cellular matrix remodeling and cell migration were changed in lesional macrophages 1 week after Apoe gene repair. However, mRNA levels of numerous genes involved in cholesterol efflux and inflammation were not significantly changed at this time point. Conclusions Restoring apoE expression in Apoeh/hLdlr−/−Mx1-cre mice resulted in lesion stabilization in the context of a human-like ratio of non-HDL:HDL-cholesterol. Our data suggest that macrophage loss derived in part from reduced blood Ly-6Chi monocytes levels and genetic reprogramming of lesional macrophages. PMID:23788760

  18. Selective proteolysis of apolipoprotein B-100 by Arg-gingipain mediates atherosclerosis progression accelerated by bacterial exposure.

    PubMed

    Hashimoto, Munetaka; Kadowaki, Tomoko; Tsukuba, Takayuki; Yamamoto, Kenji

    2006-11-01

    Epidemiological studies suggest the association of periodontal infections with atherosclerosis, however, the mechanism underlying this association remains poorly understood. Porphyromonas gingivalis is the primary etiologic agent of adult periodontitis and produces a unique class of cysteine proteinases consisting of Arg-gingipain (Rgp) and Lys-gingipain (Kgp). To elucidate key mechanisms for progression of atherosclerosis by P. gingivalis infection, we tested the effects of the disruption of genes encoding Rgp and/or Kgp and inhibitors specific for the respective enzymes on atherosclerosis progression in apolipoprotein E-knockout mice. Repeated intravenous injection of wild-type P. gingivalis resulted in an increase in atherosclerotic lesions as well as an increase in the serum LDL cholesterol and a decrease of HDL cholesterol in these animals. LDL particles in P. gingivalis-injected animals were modified as a result of selective proteolysis of apoB-100 in LDL particles. This modification of LDL by P. gingivalis resulted in an increase in LDL uptake by macrophages and consequent foam cell formation in vitro. The atherosclerotic changes induced by P. gingivalis infection were attenuated by disruption of Rgp-encoding genes or by an Rgp-specific inhibitor. Our results indicate that degradation of apoB-100 by Rgp plays a crucial role in the promotion of atherosclerosis by P. gingivalis infection. PMID:17030507

  19. Genotype rs8099917 near the IL28B gene and amino acid substitution at position 70 in the core region of the hepatitis C virus are determinants of serum apolipoprotein B-100 concentration in chronic hepatitis C.

    PubMed

    Aizawa, Yoshio; Yohizawa, Kai; Aida, Yuta; Ishiguro, Haruya; Abe, Hiroshi; Tsubota, Akihito

    2012-01-01

    The life cycle of the hepatitis C virus (HCV) is closely related to host lipoprotein metabolism. Serum levels of lipid are associated with the response to pegylated interferon plus ribavirin (PEG-IFN/RBV) therapy, while single nucleotide polymorphisms (SNPs) around the human interleukin 28B (IL28B) gene locus and amino acid substitutions in the core region of the HCV have been reported to affect the efficacy of PEG-IFN/RBV therapy in chronic hepatitis with HCV genotype 1b infection. The aim of this study was to elucidate the relationship between serum lipid and factors that are able to predict the efficacy of PEG-IFN/RB therapy, with specific focus on apolipoprotein B-100 (apoB-100) in 148 subjects with chronic HCV G1b infection. Our results demonstrated that both the aa 70 substitution in the core region of the HCV and the rs8099917 SNP located proximal to the IL28B were independent factors in determining serum apoB-100 and low-density lipoprotein (LDL) cholesterol levels. A significant association was noted between higher levels of apoB-100 (P = 1.1 × 10(-3)) and LDL cholesterol (P = 0.02) and the subjects having Arg70. A significant association was also observed between subjects carrying the rs8099917 TT responder genotype and higher levels of apoB-100 (P = 6.4 × 10(-3)) and LDL cholesterol (P = 4.2 × 10(-3)). Our results suggest that apoB-100 and LDL cholesterol are markers of impaired cellular lipoprotein pathways and/or host endogenous interferon response to HCV in chronic HCV infection. In particular, serum apoB-100 concentration might be an informative marker for judging changes in HCV-associated intracellular lipoprotein metabolism in patients carrying the rs8099917 responder genotype. PMID:21879313

  20. Reduced VLDL clearance in Apoe(-/-)Npc1(-/-) mice is associated with increased Pcsk9 and Idol expression and decreased hepatic LDL-receptor levels.

    PubMed

    Ishibashi, Minako; Masson, David; Westerterp, Marit; Wang, Nan; Sayers, Scott; Li, Rong; Welch, Carrie L; Tall, Alan R

    2010-09-01

    Niemann-Pick type C1 (NPC1) promotes the transport of LDL receptor (LDL-R)-derived cholesterol from late endosomes/lysosomes to other cellular compartments. NPC1-deficient cells showed impaired regulation of liver_X receptor (LXR) and sterol regulatory element-binding protein (SREBP) target genes. We observed that Apoe(-/-)Npc1(-/-) mice displayed a marked increase in total plasma cholesterol mainly due to increased VLDL, reflecting decreased clearance. Although nuclear SREBP-2 and Ldlr mRNA levels were increased in Apoe(-/-)Npc1(-/-) liver, LDL-R protein levels were decreased in association with marked induction of proprotein convertase subtilisin/kexin type 9 (Pcsk9) and inducible degrader of the LDL-R (Idol), both known to promote proteolytic degradation of LDL-R. While Pcsk9 is known to be an SREBP-2 target, marked upregulation of IDOL in Apoe(-/-)Npc1(-/-) liver was unexpected. However, several other LXR target genes also increased in Apoe(-/-)Npc1(-/-) liver, suggesting increased synthesis of endogenous LXR ligands secondary to activation of sterol biosynthesis. In conclusion, we demonstrate that NPC1 deficiency has a major impact on VLDL metabolism in Apoe(-/-) mice through modulation of hepatic LDL-R protein levels. In contrast to modest induction of hepatic IDOL with synthetic LXR ligands, a striking upregulation of IDOL in Apoe(-/-)Npc1(-/-) mice could indicate a role of endogenous LXR ligands in regulation of hepatic IDOL. PMID:20562239

  1. Estradiol protective role in atherogenesis through LDL structure modification

    NASA Astrophysics Data System (ADS)

    Papi, Massimiliano; Brunelli, Roberto; Ciasca, Gabriele; Maiorana, Alessandro; Maulucci, Giuseppe; Palmieri, Valentina; Parasassi, Tiziana; De Spirito, Marco

    2016-07-01

    Relevant physiological functions are exerted by circulating low density lipoprotein (LDL) as well as eventual pathological processes triggering atherogenesis. Modulation of these functions can well be founded on modifications of LDL structure. Given its large dimension, multicomponent organization and strong interactions between the protein apoB-100 and lipids, determining LDL 3D structure remains a challenge. We propose a novel quantitative physical approach to this complex biological problem. We introduce a three-component model, fitted to small angle x-ray scattering data on LDL maintained in physiological conditions, able to achieve a consistent 3D structure. Unexpected features include three distinct protein domains protruding out of a sphere, quite rough in its surface, where several core lipid areas are exposed. All LDL components are affected by 17-β-estradiol (E2) binding to apoB-100. Mostly one of the three protruding protein domains, dramatically reducing its presence on the surface and with a consequent increase of core lipids’ exposure. This result suggests a structural basis for some E2 protecting roles and LDL physiological modifications.

  2. Screening and identification of familial defective apolipoprotein B-100 in clinical samples by capillary gel electrophoresis.

    PubMed

    Lehmann, R; Koch, M; Pfohl, M; Voelter, W; Häring, H U; Liebich, H M

    1996-09-13

    Familial defective apolipoprotein B-100 (FDB) is a dominantly inherited disorder. It is characterized by a decreased affinity of low density lipoprotein (LDL) for the LDL receptor, as a consequence of a substitution of adenine by guanine in exon 26 of the apolipoprotein B-100 gene, coding for the putative LDL receptor-binding domain of the mature protein. This disorder is associated with a strikingly high incidence of arteriosclerosis and tends to cause disease and premature death. In this communication we describe a rapid capillary gel electrophoretic method in combination with molecular biology techniques to facilitate the diagnosis of FDB. Mutation screening for FDB is performed by an allele-specific amplification followed by capillary gel electrophoresis (CGE). For the combined polymerase chain reaction (PCR)-CGE method, a total analysis time of only 3 h is needed, a period that is normally necessary for the run and for staining of the gel only, not including the time for PCR, gel casting, etc. In our pilot study 4 of 43 hypercholesterolemic patients were found to have the predominant apoB 3500 codon mutation. The verification is demonstrated by DNA-sequencing. This pilot study will be followed by a large cohort analysis of the south-west German population to determine the frequency of FDB in this area. The PCR-CGE method on the Dionex capillary electrophoresis system (CES I) allows rapid, fully automated detection of the mutation resulting in the unequivocal diagnosis of FDB. PMID:8843667

  3. Effect of low density lipoprotein receptor deficiency on the metabolism of apolipoprotein B-100 in blood plasma. Kinetic studies in normal and Watanabe heritable hyperlipidemic rabbits.

    PubMed Central

    Yamada, N; Shames, D M; Havel, R J

    1987-01-01

    The kinetics of apolipoprotein (apo) B-100 in particles containing apo E (B,E particles) or lacking apo E (B particles) were studied in Watanabe heritable hyperlipidemic (WHHL) rabbits deficient in low density lipoprotein (LDL) receptors, and compared with those of normal rabbits after injection of radioiodinated very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL), and LDL. In both groups results of kinetic modeling were consistent with the hypothesis that all apo B enters the plasma in VLDL, mainly as B,E particles, followed by delipidation and partial conversion to IDL and LDL, with concomitant conversion of some B,E particles to B particles. In WHHL rabbits, production of VLDL apo B was reduced by 40%, but LDL production was increased threefold. Defective removal of B,E and B particles in all three lipoprotein classes, coupled with preserved processes of delipidation, can account for the observed increases in the concentration of apo B (threefold in VLDL, fivefold in IDL, and twenty-twofold in LDL) in WHHL rabbits. PMID:3611356

  4. Application of Multianalyte Microphysiometry to Characterize Macrophage Metabolic Responses to Oxidized LDL and Effects of an ApoA-1 Mimetic

    PubMed Central

    Kimmel, Danielle W.; Dole, William P.; Cliffel, David E.

    2013-01-01

    Although the interaction of macrophages with oxidized low density liopoprotein (oxLDL) is critical to the pathogenesis of atherosclerosis, relatively little is known about their metabolic response to oxLDL. Our development of the multianalyte microphysiometer (MAMP) allows for simultaneous measurement of extracellular metabolic substrates and products in real-time. Here, we use the MAMP to study changes in the metabolic rates of RAW-264.7 cells undergoing respiratory burst in response to oxLDL. These studies indicate that short duration exposure of macrophages to oxLDL results in time-dependent increases in glucose and oxygen consumption and in lactate production and extracellular acidification rate. Since apolipoprotein A-I (apoA-I) and apoA-I mimetics prevent experimental atherosclerosis, we hypothesized that the metabolic response of the macrophage during respiratory burst can be modulated by apoA-I mimetics. We tested this hypothesis by examining the effects of the apoA-I peptide mimetic, L-4F, alone and complexed with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) on the macrophage metabolic response to oxLDL. L-4F and the DMPC/L-4F complexes attenuated the macrophage respiratory burst in response to oxLDL. The MAMP provides a novel approach for studying macrophage ligand-receptor interactions and cellular metabolism and our results provide new insights into the metabolic effects of oxLDL and mechanism of action of apoA-I mimetics. PMID:23313489

  5. ApoC-III inhibits clearance of triglyceride-rich lipoproteins through LDL family receptors.

    PubMed

    Gordts, Philip L S M; Nock, Ryan; Son, Ni-Huiping; Ramms, Bastian; Lew, Irene; Gonzales, Jon C; Thacker, Bryan E; Basu, Debapriya; Lee, Richard G; Mullick, Adam E; Graham, Mark J; Goldberg, Ira J; Crooke, Rosanne M; Witztum, Joseph L; Esko, Jeffrey D

    2016-08-01

    Hypertriglyceridemia is an independent risk factor for cardiovascular disease, and plasma triglycerides (TGs) correlate strongly with plasma apolipoprotein C-III (ApoC-III) levels. Antisense oligonucleotides (ASOs) for ApoC-III reduce plasma TGs in primates and mice, but the underlying mechanism of action remains controversial. We determined that a murine-specific ApoC-III-targeting ASO reduces fasting TG levels through a mechanism that is dependent on low-density lipoprotein receptors (LDLRs) and LDLR-related protein 1 (LRP1). ApoC-III ASO treatment lowered plasma TGs in mice lacking lipoprotein lipase (LPL), hepatic heparan sulfate proteoglycan (HSPG) receptors, LDLR, or LRP1 and in animals with combined deletion of the genes encoding HSPG receptors and LDLRs or LRP1. However, the ApoC-III ASO did not lower TG levels in mice lacking both LDLR and LRP1. LDLR and LRP1 were also required for ApoC-III ASO-induced reduction of plasma TGs in mice fed a high-fat diet, in postprandial clearance studies, and when ApoC-III-rich or ApoC-III-depleted lipoproteins were injected into mice. ASO reduction of ApoC-III had no effect on VLDL secretion, heparin-induced TG reduction, or uptake of lipids into heart and skeletal muscle. Our data indicate that ApoC-III inhibits turnover of TG-rich lipoproteins primarily through a hepatic clearance mechanism mediated by the LDLR/LRP1 axis. PMID:27400128

  6. LDL particle core enrichment in cholesteryl oleate increases proteoglycan binding and promotes atherosclerosis[S

    PubMed Central

    Melchior, John T.; Sawyer, Janet K.; Kelley, Kathryn L.; Shah, Ramesh; Wilson, Martha D.; Hantgan, Roy R.; Rudel, Lawrence L.

    2013-01-01

    Several studies in humans and animals suggest that LDL particle core enrichment in cholesteryl oleate (CO) is associated with increased atherosclerosis. Diet enrichment with MUFAs enhances LDL CO content. Steroyl O-acyltransferase 2 (SOAT2) is the enzyme that catalyzes the synthesis of much of the CO found in LDL, and gene deletion of SOAT2 minimizes CO in LDL and protects against atherosclerosis. The purpose of this study was to test the hypothesis that the increased atherosclerosis associated with LDL core enrichment in CO results from an increased affinity of the LDL particle for arterial proteoglycans. ApoB-100-only Ldlr−/− mice with and without Soat2 gene deletions were fed diets enriched in either cis-MUFA or n-3 PUFA, and LDL particles were isolated. LDL:proteogylcan binding was measured using surface plasmon resonance. Particles with higher CO content consistently bound with higher affinity to human biglycan and the amount of binding was shown to be proportional to the extent of atherosclerosis of the LDL donor mice. The data strongly support the thesis that atherosclerosis was induced through enhanced proteoglycan binding of LDL resulting from LDL core CO enrichment. PMID:23804810

  7. Softness of atherogenic lipoproteins: a comparison of very low density lipoprotein (VLDL) and low density lipoprotein (LDL) using elastic incoherent neutron scattering (EINS).

    PubMed

    Mikl, Christian; Peters, Judith; Trapp, Marcus; Kornmueller, Karin; Schneider, Wolfgang J; Prassl, Ruth

    2011-08-31

    Apolipoprotein B100 (apoB100)-containing plasma lipoproteins (LDL and VLDL) supply tissues and cells with cholesterol and fat. During lipolytic conversion from VLDL to LDL the size and chemical composition of the particles change, but the apoB100 molecule remains bound to the lipids and regulates the receptor mediated uptake. The molecular physical parameters which control lipoprotein remodeling and enable particle stabilization by apoB100 are largely unknown. Here, we have compared the molecular dynamics and elasticities of VLDL and LDL derived by elastic neutron scattering temperature scans. We have determined thermal motions, dynamical transitions, and molecular fluctuations, which reflect the temperature-dependent motional coupling between lipid and protein. Our results revealed that lipoprotein particles are extremely soft and flexible. We found substantial differences in the molecular resiliences of lipoproteins, especially at higher temperatures. These discrepancies not only can be explained in terms of lipid composition and mobility but also suggest that apoB100 displays different dynamics dependent on the lipoprotein it is bound to. Hence, we suppose that the inherent conformational flexibility of apoB100 permits particle stabilization upon lipid exchange, whereas the dynamic coupling between protein and lipids might be a key determinant for lipoprotein conversion and atherogenicity. PMID:21790144

  8. Enhancing the Contrast of ApoB to Locate the Surface Components in the 3D Density Map of Human LDL

    PubMed Central

    Liu, Yuhang; Atkinson, David

    2010-01-01

    A 26Å resolution map of the structure of human LDL was obtained from cryo-EM and single particle image reconstruction. The structure showed a discoidal shaped LDL particle with high-density regions mainly distributed at the edge of the particle and low-density regions at the flat surface that covers the core region. To determine the chemical components that correspond to these density regions and to delineate the distribution of protein and phospholipid located at the particle surface at the resolution of the map, we used Mono-Sulfo-NHS-Undecagold labeling to increase preferentially the contrast of the apoB protein component on the LDL particle. In the 3D maps from the image reconstruction of the undecagold labeled LDL particles, the high-density region from the undecagold label was distributed mainly at the edge of the particle and lower density regions were found at the flat surfaces that cover the neutral lipid core. This suggests that apoB mainly encircles LDL at the edge of the particle and the phospholipid monolayers are located at the flat surfaces, which are parallel to the cholesterol ester layers in the core and may interact with the core lipid layers through the acyl-chains. PMID:21029740

  9. Induction of Fatal Inflammation in LDL Receptor and ApoA-I Double-Knockout Mice Fed Dietary Fat and Cholesterol

    PubMed Central

    Zabalawi, Manal; Bhat, Shaila; Loughlin, Tara; Thomas, Michael J.; Alexander, Eric; Cline, Mark; Bullock, Bill; Willingham, Mark; Sorci-Thomas, Mary G.

    2003-01-01

    Atherogenic response to dietary fat and cholesterol challenge was evaluated in mice lacking both the LDL receptor (LDLr−/−) and apoA-I (apoA-I−/−) gene, LDLr−/−/apoA-I−/− or double-knockout mice. Gender- and age-matched LDLr−/−/apoA-I−/− mice were fed a diet consisting of 0.1% cholesterol and 10% palm oil for 16 weeks and compared to LDLr−/− mice or single-knockout mice. The LDLr−/− mice showed a 6- to 7-fold increase in total plasma cholesterol (TPC) compared to their chow-fed mice counterparts, while LDLr−/−/apoA-I−/− mice showed only a 2- to 3-fold increase in TPC compared to their chow-fed controls. This differential response to the atherogenic diet was unanticipated, since chow-fed LDLr−/− and LDLr−/−/apoA-I−/− mice began the study with similar LDL levels and differed primarily in their HDL concentration. The 6-fold diet-induced increase in TPC observed in the LDLr−/− mice occurred mainly in VLDL/LDL and not in HDL. Mid-study plasma samples taken after 8 weeks of diet feeding showed that LDLr−/− mice had TPC concentrations approximately 60% of their 16-week level, while the LDLr−/−/apoA-I−/− mice had reached 100% of their 16-week TPC concentration after only 8 weeks of diet. Male LDLr−/− mice showed similar aortic cholesterol levels to male LDLr−/−/apoA-I−/− mice despite a 4-fold higher VLDL/LDL concentration in the LDLr−/− mice. A direct comparison of the severity of aortic atherosclerosis between female LDLr−/− and LDLr−/−/apoA-I−/− mice was compromised due to the loss of female LDLr−/−/apoA-I−/− mice between 10 and 14 weeks into the study. Diet-fed female and, with time, male LDLr−/−/apoA-I−/− mice suffered from severe ulcerated cutaneous xanthomatosis. This condition, combined with a complete depletion of adrenal cholesterol, manifested in fatal wasting of the affected mice. In conclusion, LDLr−/− and LDLr−/−/apoA-I−/− mice showed

  10. DNA methylation in cystathionine-γ-lyase (CSE) gene promoter induced by ox-LDL in macrophages and in apoE knockout mice.

    PubMed

    Du, Hua-Ping; Li, Jiaojiao; You, Shou-Jiang; Wang, Ya-Li; Wang, Fen; Cao, Yong-Jun; Hu, Li-Fang; Liu, Chun-Feng

    2016-01-15

    Recent studies suggest that epigenetic alterations such as DNA methylation control many aspects of monocytes/macrophages and participate in the pathogenesis of atherosclerosis, a lipid-driven inflammatory disorder. Our and other groups demonstrated that dysregulation of cystathionine γ-lyase (CSE) -hydrogen sulfide (H2S) pathway was involved in monocyte/macrophages-mediated inflammation and atherosclerosis. However, it remains unknown whether altered cse methylation in macrophages may play a role in linking CSE-H2S dysregulation and atherosclerosis. In the present study, we showed that plasma H2S and H2S production in the peritoneal macrophages of apolipoprotein knockout (apoE(-/-)) mice gradually decreased with ages, and were also lower than that in control mice at 12 weeks older. Moreover, CSE mRNA expressions decreased while DNA methyltransferase (DNMT) expressions increased in the peritoneal macrophages isolated from apoE(-/-) mice, compared to age-matched wildtype mice. Similar observations were obtained in an in vitro study. In oxidized low-density lipoprotein (ox-LDL)-treated raw264.7 macrophages, cse transcription was down-regulated while the expression and activity of DNMT was up-regulated, associated with enhanced DNA methylation in cse promoter. Suppression of DNMT with its inhibitor or siRNA reversed the decrease of CSE mRNA. Therefore, our data suggest that DNA hypermethylation of CpG rich region in cse promoter might contribute to the decrease of cse transcription and H2S production in macrophages, and thus contribute to atherosclerosis development. PMID:26692478

  11. Quantitative X-Ray Imaging of Intraplaque Hemorrhage in Aortas of ApoE-/-/LDL-/- Double Knockout Mice

    SciTech Connect

    Langheinrich,A.; Michniewicz, A.; Sedding, D.; Lai, B.; Jorgensen, S.; Bohle, R.; Ritman, E.

    2007-01-01

    Objectives: To determine if hemorrhage into an arterial wall can be detected in CT images by virtue of the iron content. Materials and Methods: Aortas from male apoE-/-/LDL-/- mice (n = 31) were infused in situ with contrast agent, for micro-CT scanning and histology. Roentgen-opacities within the aortic walls were identified by histology and micro-x-ray fluorescence to be iron or calcium. Dual-energy scanning was performed at 2 energy levels using synchrotron-based micro-CT [(2 {mu}m)3 voxels, 16 and 20 keV] and 64-slice CT (0.4 x 0.4 x 0.6 mm voxels, 80 and 120 kVp). Results: Opacities were identified as hemorrhage-related clusters of multiple punctate deposits, containing both Fe (0.48 x 10-12 g/voxel) and Ca (3.18 x 10-2 g/voxel), or as isolated confluent accumulations of exclusively calcium. Subtraction of the dual-energy CT scans discriminated iron from calcium deposits. Conclusion: Detection and quantification of iron deposits in hemorrhaged atherosclerotic lesions is feasible by dual-energy CT imaging.

  12. Evidence for a partial deficiency of the LDL (apo B,E) receptor within a family of rhesus monkeys with a spontaneous hypercholesterolemia

    SciTech Connect

    Scanu, A.M.; Khalil, A.; Tidore, M.; Kaiser, M.; Pfaffinger, D.; Carey, D.; Dawson, G.

    1987-05-01

    Spontaneous hypercholesterolemia is rare among non-human primates. Through screening of a rhesus monkey colony they have identified a family in which 3 out of its 6 members have a persistent hypercholesterolemia on a cholesterol-free Purina Chow diet and are high responders to a dietary fat challenge. On a basal diet the 3 affected animals also exhibited high plasma levels of LDL and apoB. To shed light on the mechanism of the hypercholesterolemia they have grown in culture fibroblasts from skin biopsies obtained from all members of the rhesus monkey family and 12 control. Binding studies at 4/sup 0/C and ligand blotting experiments using /sup 125/I-LDL of either normolipidemic rhesus monkeys or human subjects have shown that the fibroblasts from the 3 monkeys with a spontaneous hypercholesterolemia have a significant reduction of the number of LDL receptor and to the same extent as fibroblasts derived from subjects with heterozygous FH studied at the same time. The data suggest that the spontaneous elevation of plasma cholesterol observed in the 3 family members is related, at least in part, to a defective uptake of LDL by the LDL receptor pathway.

  13. Effects of D-4F on Vasodilation and Vessel Wall Thickness in Hypercholesterolemic LDL Receptor Null and LDL receptor/ApoA-I Double Knockout Mice on Western Diet

    PubMed Central

    Ou, Jingsong; Wang, Jingli; Xu, Hao; Ou, Zhijun; Sorci-Thomas, Mary G.; Jones, Deron W.; Signorino, Paul; Densmore, John C.; Kaul, Sushma; Oldham, Keith T.; Pritchard, Kirkwood A.

    2005-01-01

    Previously we showed L-4F, a novel apolipoprotein A-I (apoA-I) mimetic, improved vasodilation in two dissimilar models of vascular disease; hypercholesterolemic low-density lipoprotein (LDL) receptor null (Ldlr −/−) mice and transgenic sickle cell disease mice. Here we determine the mechanisms by which D-4F improves vasodilation and arterial wall thickness in hypercholesterolemic Ldlr −/− mice and Ldlr −/−/apoA-I null (apoA-I −/−), double knockout mice. Ldlr −/− and Ldlr −/−/apoA-I −/− mice were fed western diet (WD) ± D-4F. Oral D-4F restored endothelium- and eNOS-dependent vasodilation in direct relationship to duration of treatments and reduced wall thickness in as little as 2 weeks in vessels with pre-existing disease in Ldlr −/− mice. D-4F had no effect on total or HDL cholesterol concentrations but reduced proinflammatory HDL levels. D-4F had no effect on plasma myeloperoxidase (MPO) concentrations but reduced MPO association with apoA-I as well as 3-nitrotyrosine in apoA-I. D-4F increased endothelium- and eNOS-dependent vasodilation in Ldlr −/−/apoA-I −/− mice but did not reduce wall thickness as it had in Ldlr −/− mice. Vascular endothelial cells were treated with 22-hydroxycholesterol (22-OHC) ± L-4F. 22-OHC decreased nitric oxide (•NO) and increased superoxide anion (O2 •−) production and increased ABCA-1 and collagen expression. L-4F restored •NO and O2 •− balance, had little effect on ABCA-1 expression but reduced collagen expression. These data demonstrate that although D-4F restores vascular endothelial cell and eNOS function to increase vasodilation, HDL containing apoA-I, or at least some critical concentration of the anti-atherogenic lipoprotein, is required for D-4F to decrease vessel wall thickness. PMID:16224061

  14. Familial ligand-defective apolipoprotein B. Identification of a new mutation that decreases LDL receptor binding affinity.

    PubMed

    Pullinger, C R; Hennessy, L K; Chatterton, J E; Liu, W; Love, J A; Mendel, C M; Frost, P H; Malloy, M J; Schumaker, V N; Kane, J P

    1995-03-01

    Detection of new ligand-defective mutations of apolipoprotein B (apoB) will enable identification of sequences involved in binding to the LDL receptor. Genomic DNA from patients attending a lipid clinic was screened by single-strand conformation polymorphism analysis for novel mutations in the putative LDL receptor-binding domain of apoB-100. A 46-yr-old woman of Celtic and Native American ancestry with primary hypercholesterolemia (total cholesterol [TC] 343 mg/dl; LDL cholesterol [LDL-C] 241 mg/dl) and pronounced peripheral vascular disease was found to be heterozygous for a novel Arg3531-->Cys mutation, caused by a C-->T transition at nucleotide 10800. One unrelated 59-yr-old man of Italian ancestry was found with the same mutation after screening 1,560 individuals. He had coronary heart disease, a TC of 310 mg/dl, and an LDL-C of 212 mg/dl. A total of eight individuals were found with the defect in the families of the two patients. They had an age- and sex-adjusted TC of 240 +/- 14 mg/dl and LDL-C of 169 +/- 10 mg/dl. This compares with eight unaffected family members with age- and sex-adjusted TC of 185 +/- 12 mg/dl and LDL-C of 124 +/- 12 mg/dl. In a dual-label fibroblast binding assay, LDL from the eight subjects with the mutation had an affinity for the LDL receptor that was 63% that of control LDL. LDL from eight unaffected family members had an affinity of 91%. By way of comparison, LDL from six patients heterozygous for the Arg3500-->Gln mutation had an affinity of 36%. The percentage mass ratio of the defective Cys3531 LDL to normal LDL was 59:41, as determined using the mAb MB19 and dynamic laser light scattering. Thus, the defective LDL had accumulated in the plasma of these patients. Using this mass ratio, it was calculated that the defective Cys3531 LDL particles bound with 27% of normal affinity. Deduced haplotypes using 10 apoB gene markers showed the Arg3531-->Cys alleles to be different in the two kindreds and indicates that the mutations arose

  15. Apolipoprotein B100 secretion by cultured ARPE-19 cells is modulated by alteration of cholesterol levels.

    PubMed

    Wu, Tinghuai; Fujihara, Masashi; Tian, Jane; Jovanovic, Miroslava; Grayson, Celene; Cano, Marisol; Gehlbach, Peter; Margaron, Philippe; Handa, James T

    2010-09-01

    Cholesteryl ester rich apolipoprotein B100 (apoB100) lipoproteins accumulate in Bruch's membrane before the development of age-related macular degeneration. It is not known if these lipoproteins come from the circulation or local ocular tissue. Emerging, but incomplete evidence suggests that the retinal pigmented epithelium (RPE) can secrete lipoproteins. The purpose of this investigation was to determine (i) whether human RPE cells synthesize and secrete apoB100, and (ii) whether this secretion is driven by cellular cholesterol, and if so, (iii) whether statins inhibit this response. The established, human derived ARPE-19 cells challenged with 0-0.8 mM oleic acid accumulated cellular cholesterol, but not triglycerides. Oleic acid increased the amount of apoB100 protein recovered from the medium by both western blot analysis and (35) S-radiolabeled immunoprecipitation while negative stain electron microscopy showed lipoprotein-like particles. Of nine statins evaluated, lipophilic statins induced HMG-CoA reductase mRNA expression the most. The lipophilic Cerivastatin (5 μM) reduced cellular cholesterol by 39% and abrogated apoB100 secretion by 3-fold. In contrast, the hydrophilic statin Pravastatin had minimal effect on apoB100 secretion. These data suggest that ARPE-19 cells synthesize and secrete apoB100 lipoproteins, that this secretion is driven by cellular cholesterol, and that statins can inhibit apoB100 secretion by reducing cellular cholesterol. PMID:20598021

  16. Construction of a biotinylated cameloid-like antibody for lable-free detection of apolipoprotein B-100.

    PubMed

    Li, Henan; Yan, Junrong; Ou, Weijun; Liu, Hong; Liu, Songqin; Wan, Yakun

    2015-02-15

    Nanobodies (Nbs), also known as the variable domain of the heavy-chain-only antibody (VHH), are single-domain antigen-binding fragments derived from heavy-chain antibodies that occur naturally in sera of camelids. Due to their unique properties of small size (15 kD), intrinsic stability, high affinity and specificity, Nbs are suitable for detecting clinical relevant antigens. Apolipoprotein B-100 (ApoB-100) is a highly predictive marker for coronary artery disease (CAD), which is frequently detected in clinical diagnosis. Herein, we successfully obtained anti-ApoB-100 Nbs for the first time and further fabricated a label-free and sensitive immunosensor for ApoB-100 based on isolated anti-ApoB-100 nanobody (Nb) using the electrochemical impedance spectroscopy (EIS) technique. We have generated an immunized phage display library against ApoB-100 and isolated four anti-ApoB-100 Nbs with high affinity and stability. The Nb with the highest affinity was biotinylated based on in vivo BirA system. Further, we developed a label-free electrochemical impedance immunosensor for ApoB-100 using this anti-ApoB-100 Nb. The attachment of ApoB-100 onto the anti-ApoB-100 Nb-immobilized sensing layer led to the increased electron-transfer resistance, which was proportional to ApoB-100 concentration in the range from 0.05 to 5 ng mL(-1) with a detection limit of 0.03 ng mL(-1). This proposed immunosensor revealed high specificity to detect ApoB-100, acceptable intra-assay precision and good stability, functioning as a feasible technique for CAD diagnosis. PMID:25203942

  17. Complex effects of inhibiting hepatic apolipoprotein B100 synthesis in humans

    PubMed Central

    Reyes-Soffer, Gissette; Moon, Byoung; Hernandez-Ono, Antonio; Dionizovik-Dimanovski, Marija; Jimenez, Jhonsua; Obunike, Joseph; Thomas, Tiffany; Ngai, Colleen; Fontanez, Nelson; Donovan, Daniel S.; Karmally, Wahida; Holleran, Stephen; Ramakrishnan, Rajasekhar; Mittleman, Robert S.; Ginsberg, Henry N.

    2016-01-01

    Mipomersen is a 20mer antisense oligonucleotide (ASO) that inhibits apolipoprotein B (apoB) synthesis; its low-density lipoprotein (LDL)–lowering effects should therefore result from reduced secretion of very-low-density lipoprotein (VLDL). We enrolled 17 healthy volunteers who received placebo injections weekly for 3 weeks followed by mipomersen weekly for 7 to 9 weeks. Stable isotopes were used after each treatment to determine fractional catabolic rates and production rates of apoB in VLDL, IDL (intermediate-density lipoprotein), and LDL, and of triglycerides in VLDL. Mipomersen significantly reduced apoB in VLDL, IDL, and LDL, which was associated with increases in fractional catabolic rates of VLDL and LDL apoB and reductions in production rates of IDL and LDL apoB. Unexpectedly, the production rates of VLDL apoB and VLDL triglycerides were unaffected. Small interfering RNA–mediated knockdown of apoB expression in human liver cells demonstrated preservation of apoB secretion across a range of apoB synthesis. Titrated ASO knockdown of apoB mRNA in chow-fed mice preserved both apoB and triglyceride secretion. In contrast, titrated ASO knockdown of apoB mRNA in high-fat–fed mice resulted in stepwise reductions in both apoB and triglyceride secretion. Mipomersen lowered all apoB lipoproteins without reducing the production rate of either VLDL apoB or triglyceride. Our human data are consistent with longstanding models of posttranscriptional and posttranslational regulation of apoB secretion and are supported by in vitro and in vivo experiments. Targeting apoB synthesis may lower levels of apoB lipoproteins without necessarily reducing VLDL secretion, thereby lowering the risk of steatosis associated with this therapeutic strategy. PMID:26819195

  18. [THE LIPOLYSIS IN PHYLOGENETICALLY EARLY LIPOPROTEINS OF LOW DENSITY AND MORE LATER LIPOPROTEINS OF VERY LOW DENSITY: FUNCTION AND DIAGNOSTIC VALUE OF APOE AND APOC-III].

    PubMed

    Rozhkova, T A; Titov, V N; Amelyushkina, V A; Kaba, S I; Kukhartchuk, V V

    2015-12-01

    According to phylogenetic theory of general pathology, the function of low density lipoproteins (LDL) and hydrolysis of triglycerides (TG) in them under the effect of hepatic glycerol hydrolase apoC-III (HGH) developed at much earlier stages of phylogenesis than functioning of insulin-dependent phylogenetically late very low density lipoproteins (VLDL). For millions ofyears, lipolysis and HGH+apoC-III have activated transfer of polyenic fatty acids (FA) in the form of cholesteryl polyesters (CLE) from high density lipoproteins (HDL) to linoleic and linolenic LDL under the effect of cholesteryl ester transfer protein. It is reasonable to suggest that hepatocytes physiologically secrete oleic and palmitic VLDL and linoleic and linolenic LDL. Cells uptake ligand oleic and palmitic VLVL by apoE/B-100 receptor-mediated endocytosis. Physiologically, VLDL are not converted to LDL. If hepatocytes secrete palmitic VLDL in greater amounts than oleic VLDL upon slow hydrolysis ofpalmitic TG and under the effect of postheparinic lipoprotein lipase+apoC-II, only some proportion of palmitic TG is uptaken by cells as VLDL, and the rest is converted in ligand-free palmitic LDL These LDL increase plasma contents of TG and LDL-cholesterol and form small dense palmitic LDL. Expression of HGH+apoC-III synthesis compensates TG hydrolysis in nonphysiological palmitic LDL. In vivo, apoC-III is neither physiological no pathological inhibitor of lipolysis. Increase in plasma apoC-III content is an indicator of accumulation of non-physiological palmitic LDL and atherosclerosis-atheromatosis risk factor ApoE content ofpalmitic LDL increases together with apoC-III, i.e., apoE in ligand VLDL is not internalized via apoE/B-100 endocytosis. An increase in apoC-III and apoE contents are reliable in vivo tests for the rise inpalmitic FA, palmitic TG and excessive secretion of palmitic VLDL by hepatocytes. ApoC-III and apoE contents in LDL are additional tests to evaluate the efficiency of

  19. Small dense LDL is more susceptible to glycation than more buoyant LDL in Type 2 diabetes.

    PubMed

    Younis, Nahla N; Soran, Handrean; Pemberton, Philip; Charlton-Menys, Valentine; Elseweidy, Mohamed M; Durrington, Paul N

    2013-03-01

    Glycation of apoB (apolipoprotein B) of LDL (low-density lipoprotein) increases its atherogenicity. Concentrations of both serum glyc-apoB (glycated apoB) and SD-LDL (small dense LDL) (syn LDL3; D=1.044-1.063 g/ml) are increased in diabetes and are closely correlated. We studied whether SD-LDL is more susceptible to glycation in vitro than more buoyant LDL in statin- and non-statin-treated Type 2 diabetes mellitus. Serum SD-LDL apoB and glyc-apoB on statins was 20±2 (means±S.D.) and 3.6±0.41 compared with 47±3 and 5.89±0.68 mg/dl in those not receiving statins (P<0.001 and <0.01, respectively). There was a dose-dependent increase in glycation on incubation of LDL subfractions with glucose, which was accompanied by an increase in LPO (lipid peroxide) and electrophoretic mobility and a decrease in free amino groups. SD-LDL was more susceptible to these changes than more buoyant LDL. Both SD-LDL and more buoyant LDL from statin-treated patients were less susceptible to glycation. There were fewer free amino groups on LDL subfractions from statin-treated patients, which may contribute to this resistance. In conclusion, greater susceptibility of SD-LDL to glycation is likely to contribute to the raised levels of circulating glyc-apoB in diabetes. Statins are associated with lower levels of both SD-LDL and glyc-apoB. PMID:22985435

  20. Cross-species comparison of in vivo PK/PD relationships for second-generation antisense oligonucleotides targeting apolipoprotein B-100.

    PubMed

    Yu, Rosie Z; Lemonidis, Kristina M; Graham, Mark J; Matson, John E; Crooke, Rosanne M; Tribble, Diane L; Wedel, Mark K; Levin, Arthur A; Geary, Richard S

    2009-03-01

    The in vivo pharmacokinetics/pharmacodynamics of 2'-O-(2-methoxyethyl) (2'-MOE) modified antisense oligonucleotides (ASOs), targeting apolipoprotein B-100 (apoB-100), were characterized in multiple species. The species-specific apoB antisense inhibitors demonstrated target apoB mRNA reduction in a drug concentration and time-dependent fashion in mice, monkeys, and humans. Consistent with the concentration-dependent decreases in liver apoB mRNA, reductions in serum apoB, and LDL-C, and total cholesterol were concurrently observed in animal models and humans. Additionally, the long duration of effect after cessation of dosing correlated well with the elimination half-life of 2'-MOE modified apoB ASOs studied in mice (t(1/2) congruent with 20 days) and humans (t(1/2) congruent with 30 days) following parental administrations. The plasma concentrations of ISIS 301012, observed in the terminal elimination phase of both mice and monkeys were in equilibrium with liver. The partition ratios between liver and plasma were similar, approximately 6000:1, across species, and thus provide a surrogate for tissue exposure in humans. Using an inhibitory E(max) model, the ASO liver EC(50s) were 101+/-32, 119+/-15, and 300+/-191 microg/g of ASO in high-fat-fed (HF) mice, transgenic mice containing the human apoB transgene, and monkeys, respectively. The estimated liver EC(50) in man, extrapolated from trough plasma exposure, was 81+/-122 microg/g. Therefore, extraordinary consistency of the exposure-response relationship for the apoB antisense inhibitor was observed across species, including human. The cross-species PK/PD relationships provide confidence in the use of pharmacology animal models to predict human dosing for second-generation ASOs targeting the liver. PMID:19056355

  1. Microsomal triacylglycerol transfer protein prevents presecretory degradation of apolipoprotein B-100. A dithiothreitol-sensitive protease is involved.

    PubMed

    Benoist, F; Nicodeme, E; Grand-Perret, T

    1996-09-15

    The role of microsomal triacylglycerol transfer protein (MTP) in the secretion of apolipoprotein B-100 (apoB-100) has been studied using an inhibitor of MTP: 4'-bromo-3'-methylmetaqualone. In vitro, this compound inhibits trioleoylglycerol transfer between lipid vesicles mediated by MTP with an IC50 of 0.9 microM whereas it does not inhibit the lipid transfer mediated by the cholesteryl ester transfer protein. In HepG2 cells, 4'-bromo-3'-methylmetaqualone inhibits the secretion of apoB-100 with an IC50 of 0.3 microM, without affecting the secretion of several other proteins like apoA-I or albumin. Moreover, there is no accumulation of apoB-100 in treated cells. Oleic acid, which increases apoB-100 secretion, only slightly modifies the IC50 of 4'-bromo-3'-methylmetaqualone (0.5 microM). The latter has no effect on the synthesis of major lipids within the cell, but decreases the secretion of triacylglycerol into apoB-100-containing lipoproteins. Pulse/chase experiments reveal that 4'-bromo-3'-methylmetaqualone acts on apoB-100 production either at the co-translational or post-translational level. The cysteine protease inhibitor N-acetyl-leucyl-leucyl-norleucinal does not protect apoB-100 from the 4'-bromo-3'-methylmetaqualone effect but seems to be involved in a later step of apoB-100 intracellular degradation. By contrast, dithiothreitol can totally reverse the effect of the MTP inhibitor on apoB-100 production. The mechanism of MTP-mediated lipid assembly with apoB-100 is discussed. PMID:8856075

  2. Minimally oxidized LDL inhibits macrophage selective cholesteryl ester uptake and native LDL-induced foam cell formation[S

    PubMed Central

    Meyer, Jason M.; Ji, Ailing; Cai, Lei; van der Westhuyzen, Deneys R.

    2014-01-01

    Scavenger receptor-mediated uptake of oxidized LDL (oxLDL) is thought to be the major mechanism of foam cell generation in atherosclerotic lesions. Recent data has indicated that native LDL is also capable of contributing to foam cell formation via low-affinity receptor-independent LDL particle pinocytosis and selective cholesteryl ester (CE) uptake. In the current investigation, Cu2+-induced LDL oxidation was found to inhibit macrophage selective CE uptake. Impairment of selective CE uptake was significant with LDL oxidized for as little as 30 min and correlated with oxidative fragmentation of apoB. In contrast, LDL aggregation, LDL CE oxidation, and the enhancement of scavenger receptor-mediated LDL particle uptake required at least 3 h of oxidation. Selective CE uptake did not require expression of the LDL receptor (LDL-R) and was inhibited similarly by LDL oxidation in LDL-R−/− versus WT macrophages. Inhibition of selective uptake was also observed when cells were pretreated or cotreated with minimally oxidized LDL, indicating a direct inhibitory effect of this oxLDL on macrophages. Consistent with the effect on LDL CE uptake, minimal LDL oxidation almost completely prevented LDL-induced foam cell formation. These data demonstrate a novel inhibitory effect of mildly oxidized LDL that may reduce foam cell formation in atherosclerosis. PMID:24891335

  3. Genetic and metabolic influences on LDL subclasses

    SciTech Connect

    Krauss, R.M.; Rotter, J.I.; Lusis, A.J.

    1994-09-01

    Genetic and environmental factors influence LDL particle size and density, and expression of an atherogenic lipoprotein phenotype (ALP) characterized by predominance of small, dense LDL particles. Linkage of ALP the LDL receptor locus has been reported previously. Quantitative sib-pair relative-pair linkage methodologies were used to test for linkage of LDL particle size to candidate loci in 25 large pedigrees with familial coronary artery disease. Linkage to the LDL receptor gene locus was confirmed (p=0.008). Evidence was also obtained for linkage to the genes for apoCIII, cholesteryl ester transfer protein, and manganese superoxide dismutase. The results suggest multiple genetic determinants of LDL particle size that may involve different metabolic mechanisms giving rise to small, dense LDL and increased atherosclerosis risk.

  4. Molecular cloning and expression of partial cDNAs and deduced amino acid sequence of a carboxyl-terminal fragment of human apolipoprotein B-100.

    PubMed Central

    Wei, C F; Chen, S H; Yang, C Y; Marcel, Y L; Milne, R W; Li, W H; Sparrow, J T; Gotto, A M; Chan, L

    1985-01-01

    Apolipoprotein (apo) B-100 cDNAs were identified in a human liver cDNA library cloned in the expression vector lambda gt11. The beta-galactosidase-apoB-100 fusion protein was detected by two independently produced low density lipoprotein polyclonal antisera and by three apoB-100 monoclonal antibodies that crossreact with apoB-74. It was not recognized by two apoB-100 monoclonal antibodies that crossreact with apoB-26. The longest clone, lambda B8, was completely sequenced. It contains a 2.8-kilobase DNA fragment containing the codons for the carboxyl-terminal 836 amino acid residues of apo-B-100, as well as the 3' untranslated region of apoB-100 mRNA. We have thus mapped apoB-74 to the carboxyl-terminal portion of apoB-100. The deduced amino acid sequence of the cloned DNA matches the sequences of 14 apoB-100 peptides determined in our laboratory. Minor differences in amino acid sequence were noted in three of the peptides, suggesting polymorphism of apoB-100 at the protein and DNA levels. Secondary structure predictions reveal an unusual pattern for apolipoproteins, consisting of beta-structure (24%), alpha-helical content (33%), and random structure (30%). Ten amphipathic helical regions of 10-24 residues were identified. This carboxyl-terminal fragment of apoB-100 is considerably more hydrophobic than other apolipoproteins with known structure. Its lipid binding regions might include stretches of highly hydrophobic beta-sheets as well as amphipathic helices. Our findings on apoB structure might be important for understanding the role of apoB-100-containing lipoproteins in atherosclerosis. PMID:2932736

  5. LDL Particle Testing

    MedlinePlus

    ... assessing cardiac risk in people who have a personal or family history of heart disease at a young age, especially if their total cholesterol and LDL cholesterol (LDL-C) values are not significantly elevated. LDL subfraction testing is ...

  6. Decreases in serum apolipoprotein B-100 and A-I concentrations in cows with milk fever and downer cows

    PubMed Central

    Oikawa, Shin; Katoh, Norio

    2002-01-01

    Milk fever occurring during the peripartum period has been suggested to be caused by fatty liver developed during the nonlactating stage because diseased cows have increased serum concentrations of non-esterified fatty acids (NEFA) and show hepatic lipidosis. In cows with fatty liver and related diseases such as ketosis, serum concentrations of apolipoprotein (apo) B-100 and apoA-I are decreased. The purpose of the present study was to examine whether apoB-100 and apoA-I concentrations are similarly decreased in cows with milk fever. Apolipoprotein concentrations were also measured in cows with downer syndrome, which has been suggested to be related, at least in part, to milk fever. Compared with healthy cows during early lactation, apoB-100 and apoA-I concentrations were decreased in cows with milk fever and also in downer cows. In cows with milk fever, the decreases in apoB-100 and apoA-I concentrations were associated with increased NEFA and decreased cholesterol and phospholipid concentrations. However, in downer cows, serum lipid concentration changes were not as distinct as in cows with milk fever. These results, coupled with previous findings on the decreases in apoB-100 and apoA-I concentrations of cows with fatty liver-related diseases, suggest that fatty liver is involved in the development of milk fever and partly in that of downer cow syndrome. PMID:11858646

  7. Effect of Mediterranean diet with and without weight loss on apolipoprotein B100 metabolism in men with metabolic syndrome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to assess the effect of a Mediterranean diet (MedDiet) with and without weight loss (WL) on apolipoprotein B100 (apoB100) metabolism in men with metabolic syndrome. The diet of 19 men with metabolic syndrome (age, 24–62 years) was first standardized to a North America...

  8. Metabolism of lipoproteins containing apolipoprotein B-100 in blood plasma of rabbits: heterogeneity related to the presence of apolipoprotein E.

    PubMed Central

    Yamada, N; Shames, D M; Stoudemire, J B; Havel, R J

    1986-01-01

    Apolipoprotein B-100 is a constant component of very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL), and low density lipoproteins (LDL) in mammalian blood plasma. We have found that each of these classes of lipoproteins includes particles that contain apolipoprotein E (B,E particles) as well as particles that lack this protein (B particles). These two species can be separated by immunosorption on columns of anti-apolipoprotein E bound to Sepharose. We have injected radioiodinated VLDL, IDL, and LDL intravenously into recipient rabbits and have determined the concentration of radioiodine in apolipoprotein B-100 in B,E and B particles in whole-blood plasma obtained at intervals for 24 hr. We have developed a multicompartmental model that is consistent with this new information and with current concepts of lipoprotein metabolism. The model indicates that all apolipoprotein B-100 enters the blood as VLDL, of which about 90% is in B,E particles. Most VLDL B,E particles are removed rapidly from the blood, and only a small fraction is converted to IDL and eventually to LDL (overall conversion is approximately 2%). By contrast, a much smaller fraction of VLDL B particles is removed directly, and approximately 27% is converted to LDL. In addition, some B,E particles are converted to B particles as VLDL are converted to LDL, so that most LDL particles lack apolipoprotein E. Fractional rates of irreversible removal of B,E and B particles in IDL and LDL are similar. Our results indicate that the presence of apolipoprotein E is a major determinant of the metabolic fate of VLDL particles and support the hypothesis that polyvalent binding of particles containing several molecules of apolipoprotein E promotes receptor-dependent endocytosis of hepatogenous lipoproteins and limits their conversion to lipoproteins of higher density. PMID:3458191

  9. Identification of domains in apolipoprotein B100 that confer a high requirement for the microsomal triglyceride transfer protein.

    PubMed

    Nicodeme, E; Benoist, F; McLeod, R; Yao, Z; Scott, J; Shoulders, C C; Grand-Perret, T

    1999-01-22

    The microsomal triglyceride transfer protein (MTP) is required for the assembly and secretion of apoB-containing lipoproteins. To investigate the role of MTP in lipoprotein assembly, we determined the ability of carboxyl-terminally truncated forms of apoB to be secreted from cells treated with the MTP inhibitor 4'-bromo-3'-methylmetaqualone (Benoist, F., Nicodeme, E., and Grand-Perret, T. (1996) Eur. J. Biochem. 240, 713-720). In Caco-2 and mhAT3F cells that produce apoB100 and apoB48, the inhibitor preferentially blocked apoB100 secretion. When the inhibitor was tested on McA-RH7777 cells stably transfected with cDNAs encoding human apoB100, apoB72, apoB53, apoB29, and apoB18, the secretion of apoB100, apoB72, and apoB53 was preferentially impaired relative to apoB48 and shorter forms. To delineate the region between apoB48 and apoB53 that has a high requirement for MTP, we used puromycin to generate a range of truncated forms of apoB in HepG2 cells. The secretion of apoB53 and longer forms of apoB was markedly affected by low concentrations of the MTP inhibitor (approximately 1 microM), whereas apoB51 and smaller forms of apoB were only affected at higher concentrations (> 10 microM). The size-related sensitivity to MTP inhibitor was not due to late processing or retention, since the same result was observed when nascent lipoproteins were isolated from the endoplasmic reticulum. The MTP inhibitor did not alter the density of the secreted lipoproteins, indicating that each apoB polypeptide requires a minimally defined amount of lipid to attain a secretable conformation. Our results suggest that the folding of the domain between apoB51 and apoB53 has a high requirement for lipid. This domain is predicted to form amphipathic alpha-helices and to bind lipid reversibly. It proceeds and is followed by rigid amphipathic beta-sheets that are predicted to associate with lipid irreversibly. We speculate that these domains enable apoB to switch from a stable lipid

  10. Hibiscus anthocyanins-rich extract inhibited LDL oxidation and oxLDL-mediated macrophages apoptosis.

    PubMed

    Chang, Yun-Ching; Huang, Kai-Xun; Huang, An-Chung; Ho, Yung-Chyuan; Wang, Chau-Jong

    2006-07-01

    The oxidative modification of low-density lipoprotein (LDL) plays a key role in the pathogenesis of atherosclerosis. Anti-oxidative reagents, which can effectively inhibit LDL oxidation, may prevent atherosclerosis via reducing early atherogenesis, and slowing down the progression to advance stages. As shown in previous studies Hibiscus sabdariffa L. is a natural plant containing a lot of pigments that was found to possess anti-oxidative of activity. Therefore, in this study, we evaluated the anti-oxidative activity of Hibiscus anthocyanins (HAs) by measuring their effects on LDL oxidation (in cell-free system) and anti-apoptotic abilities (in RAW264.7 cells). HAs have been tested in vitro examining their relative electrophoretic mobility (REM), Apo B fragmentation, thiobarbituric acid relative substances (TBARS) and radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity assay. The anti-oxidative activity of HAs was defined by relative electrophoretic mobility of oxLDL (decrease of 50% at 2 mg/ml), fragmentation of Apo B (inhibition of 61% at 1mg/ml), and TBARS assay (IC(50): 0.46 mg/ml) in the Cu(2+)-mediated oxidize LDL. Furthermore, the addition of >0.1 mg/ml of HAs could scavenge over 95% of free DPPH radicals, HAs showed strong potential in inhibiting LDL oxidation induced by copper. In addition, to determine whether oxLDL-induced apoptosis in macrophages is inhibited by HAs, we studied the viability, morphology and caspase-3 expression of RAW 264.7 cells. MTT assay, Leukostate staining analysis and Western blotting reveals that HAs could inhibit oxLDL-induced apoptosis. According to these findings, we suggest that HAs may be used to inhibit LDL oxidation and oxLDL-mediated macrophage apoptosis, serving as a chemopreventive agent. However, further investigations into the specificity and mechanism(s) of HAs are needed. PMID:16473450

  11. A Highly Expressed Human Protein, Apolipoprotein B-100, Serves as an Autoantigen in a Subgroup of Patients With Lyme Disease.

    PubMed

    Crowley, Jameson T; Drouin, Elise E; Pianta, Annalisa; Strle, Klemen; Wang, Qi; Costello, Catherine E; Steere, Allen C

    2015-12-01

    To discover novel autoantigens associated with Lyme arthritis (LA), we identified T-cell epitopes presented in vivo by human leukocyte antigen (HLA)-DR molecules in patients' inflamed synovial tissue or joint fluid and tested each epitope for autoreactivity. Using this approach, we identified the highly expressed human protein, apolipoprotein B-100 (apoB-100), as a target of T- and B-cell responses in a subgroup of LA patients. Additionally, the joint fluid of these patients had markedly elevated levels of apoB-100 protein, which may contribute to its autoantigenicity. In patients with antibiotic-refractory LA, the magnitude of apoB-100 antibody responses correlated with increased numbers of plasma cells in synovial tissue, greater numbers and activation of endothelial cells, and more synovial fibroblast proliferation. Thus, a subset of LA patients have high levels of apoB-100 in their joints and autoreactive T- and B-cell responses to the protein, which likely contributes to pathogenic autoimmunity in patients with antibiotic-refractory LA. PMID:26014802

  12. Therapeutic expression of hairpins targeting apolipoprotein B100 induces phenotypic and transcriptome changes in murine liver

    PubMed Central

    Maczuga, P; Verheij, J; van der Loos, C; van Logtenstein, R; Hooijer, G; Martier, R; Borel, F; Lubelski, J; Koornneef, A; Blits, B; van Deventer, S; Petry, H; Konstantinova, P

    2014-01-01

    Constitutive expression of short hairpin RNAs (shRNAs) may cause cellular toxicity in vivo and using microRNA (miRNA) scaffolds can circumvent this problem. Previously, we have shown that embedding small interfering RNA sequences targeting apolipoprotein B100 (ApoB) in shRNA (shApoB) or miRNA (miApoB) scaffolds resulted in differential processing and long-term efficacy in vivo. Here we show that adeno-associated virus (AAV)-shApoB- or AAV-miApoB-mediated ApoB knockdown induced differential liver morphology and transcriptome expression changes. Our analyses indicate that ApoB knockdown with both shApoB and miApoB resulted in alterations of genes involved in lipid metabolism. In addition, in AAV-shApoB-injected animals, genes involved in immune system activation or cell growth and death were affected, which was associated with increased hepatocyte proliferation. Subsequently, in AAV-miApoB-injected animals, changes of genes involved in oxidoreductase activity, oxidative phosphorylation and nucleic bases biosynthetic processes were observed. Our results demonstrate that long-term knockdown of ApoB in vivo by shApoB or miApoB induces several transcriptome changes in murine liver. The increased hepatocyte profileration by AAV-shRNA may have severe long-term effects indicating that AAV-mediated RNA interference therapy using artificial miRNA may be a safer approach for familial hypercholesterolemia therapy. PMID:24152580

  13. Results of the 2007 B100 Quality Survey

    SciTech Connect

    Alleman, T. L.; McCormick, R. L.

    2008-03-01

    In a 2007 analysis of samples from 52% of U.S. biodiesel (B100) producers, 90% met ASTM and other specifications for critical engine performance properties and for elements that harm emission controls.

  14. RELATIONSHIP BETWEEN LIVER FAT CONTENT AND THE RATE OF VLDL APOLIPOPROTEIN B-100 SYNTHESIS IN CHILDREN WITH PROTEIN-ENERGY MALNUTRITION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fatty infiltration of the liver is associated with an increased morbidity and mortality in children with severe protein-energy malnutrition (PEM), but its pathogenesis remains unclear. Although impaired synthesis of VLDL apolipoprotein B-100 (VLDL-apo B-100) is generally accepted as the pathogenetic...

  15. Comparison of deuterated leucine, valine, and lysine in the measurement of human apolipoprotein A-I and B-100 kinetics

    SciTech Connect

    Lichtenstein, A.H.; Cohn, J.S.; Hachey, D.L.; Millar, J.S.; Ordovas, J.M.; Schaefer, E.J. )

    1990-09-01

    The production rates of apolipoprotein (apo)B-100 in very low density lipoprotein and in low density lipoprotein and apolipoprotein A-I in high density lipoprotein were determined using a primed-constant infusion of (5,5,5,-2H3)leucine, (4,4,4,-2H3)valine, and (6,6-2H2,1,2-13C2)lysine. The three stable isotope-labeled amino acids were administered simultaneously to determine whether absolute production rates calculated using a stochastic model were independent of the tracer species utilized. Three normolipidemic adult males were studied in the constantly fed state over a 15-h period. The absolute production rates of very low density lipoprotein apoB-100 were 11.4 +/- 5.8 (leucine), 11.2 +/- 6.8 (valine), and 11.1 +/- 5.4 (lysine) mg per kg per day (mean +/- SDM). The absolute production rates for low density lipoprotein apoB-100 were 8.0 +/- 4.7 (leucine), 7.5 +/- 3.8 (valine), and 7.5 +/- 4.2 (lysine) mg per kg per day. The absolute production rates for high density lipoprotein apoA-I were 9.7 +/- 0.2 (leucine), 9.4 +/- 1.7 (valine), and 9.1 +/- 1.3 (lysine) mg per kg per day. There were no statistically significant differences in absolute synthetic rates of the three apolipoproteins when the plateau isotopic enrichment values of very low density lipoprotein apoB-100 were used to define the isotopic enrichment of the intracellular precursor pool. Our data indicate that deuterated leucine, valine, or lysine provided similar results when used for the determination of apoA-I and apoB-100 absolute production rates within plasma lipoproteins as part of a primed-constant infusion protocol.

  16. Nutritional repletion of children with severe acute malnutrition does not affect VLDL apolipoprotein B-100 synthesis rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    VLDL apo B-100 is essential for the secretion of liver fat. It is thought that synthesis of this lipoprotein is impaired in childhood severe acute malnutrition (SAM), especially in the edematous syndromes, and that this contributes to the common occurrence of hepatic steatosis in this condition. How...

  17. Effects of dietary saturated fat on LDL subclasses and apolipoprotein CIII in men

    PubMed Central

    Faghihnia, Nastaran; Mangravite, Lara M.; Chiu, Sally; Bergeron, Nathalie; Krauss, Ronald M.

    2012-01-01

    Background/Objectives Small dense LDL particles and apolipoprotein (apo) CIII are risk factors for cardiovascular disease (CVD) that can be modulated by diet, but there is little information regarding the effects of dietary saturated fat on their plasma levels. We tested the effects of high vs. low saturated fat intake in the context of a high beef protein diet on levels and composition of LDL subclasses and on apoCIII levels in plasma and LDL. Subjects/Methods Following consumption of a baseline diet (50% CHO, 13% protein, 38% total fat, 15% saturated fat) for 3 wk, 14 healthy men were randomly assigned to two reduced carbohydrate high beef protein diets (31% CHO, 31% protein, 38% fat) that differed in saturated fat content (15% vs. 8%) for 3 wk each in a crossover design. Results The high saturated fat diet resulted in higher mass concentrations of buoyant LDL I, medium density LDL II and dense LDL III, but not the very dense LDL IV; and significant increases in plasma and LDL apoCIII concentration of 9.4% and 33.5%, respectively. The saturated fat-induced changes in LDL apoCIII were specifically correlated with changes in apoCIII content of LDL IV. Conclusions Taken together with previous observations, these findings suggest that, at least in the context of a lower carbohydrate high beef protein diet, high saturated fat intake may increase CVD risk by metabolic processes that involve apoCIII. PMID:22948944

  18. 2006 B100 Quality Survey Results: Milestone Report

    SciTech Connect

    Alleman, T. L.; McCormick, R. L.; Deutch, S.

    2007-05-01

    In 2006, the National Renewable Energy Laboratory conducted a nationwide quality survey of pure biodiesel (B100) intended to be used as a blendstock. The study collected random samples throughout the United States and analyzed them for quality against the current and proposed ASTM D6751 fuel quality specifications.

  19. Sortilin facilitates VLDL-B100 secretion by insulin sensitive McArdle RH7777 cells.

    PubMed

    Sparks, Robert P; Guida, Wayne C; Sowden, Mark P; Jenkins, Jermaine L; Starr, Matthew L; Fratti, Rutilio A; Sparks, Charles E; Sparks, Janet D

    2016-09-16

    Studies examining the relationship between cellular sortilin and VLDL-B100 secretion demonstrate inconsistent results. Current studies explore the possibility that discrepancies may be related to insulin sensitivity. McArdle RH7777 cells (McA cells) cultured under serum enriched conditions lose sensitivity to insulin. Following incubation in serum-free DMEM containing 1% BSA, McA cells become insulin responsive and demonstrate reduced apo B secretion. Current studies indicate that insulin sensitive McA cells express lower cellular sortilin that corresponds with reduction in VLDL-B100 secretion without changes in mRNA of either sortilin or apo B. When sortilin expression is further reduced by siRNA knockdown (KD), there are additional decreases in VLDL-B100 secretion. A crystal structure of human sortilin (hsortilin) identifies two binding sites on the luminal domain for the N- and C-termini of neurotensin (NT). A small organic compound (cpd984) was identified that has strong theoretical binding to the N-terminal site. Both cpd984 and NT bind hsortilin by surface plasmon resonance. In incubations with insulin sensitive McA cells, cpd984 was shown to enhance VLDL-B100 secretion at each level of sortilin KD suggesting cpd984 acted through sortilin in mediating its effect. Current results support a role for sortilin to facilitate VLDL-B100 secretion which is limited to insulin sensitive McA cells. Inconsistent reports of the relationship between VLDL-B100 secretion and sortilin in previous studies may relate to differing functions of sortilin in VLDL-B100 secretion depending upon insulin sensitivity. PMID:27495870

  20. Quantum-dot biosensor for hybridization and detection of R3500Q mutation of apolipoprotein B-100 gene.

    PubMed

    Mazloum-Ardakani, Mohammad; Aghaei, Roghayyeh; Heidari, Mohammad Mehdi

    2015-10-15

    A quantum-dot electrode system was developed as a transducer surface for covalent immobilization of a designed synthetic ApoB-100 specific probe, DNA hybridization and monitoring of DNA synthesis for the sensitive detection of R3500Q mutation of apolipoprotein B-100 (ApoB-100) gene. CdS-QDs cause an improvement in the fundamental characteristics of the electrode interface, such as its electroactive surface area, diffusion coefficient and electron transfer kinetics. The sensing characteristics of this biosensor offer a suitable potential for detection of target oligonucleotide with a detection limit of 3.4 × 10(-17)M. Also, the electrochemical responses of single-stranded DNA (ssDNA), DNA hybridization and DNA synthesis were investigated using electrochemical impedance spectroscopy (EIS). The extracted genomic DNA was detected based on changes in the charge transfer resistance (RCT) with [Fe(CN)6](3-/4-) as a redox probe. The proposed biosensor can distinguish between the normal sequence and the mutant sequence of ApoB-100 gene, promising a possibility to apply the QD-based biosensor for clinical investigations. PMID:26022781

  1. Upregulation of hepatic LDL transport by n-3 fatty acids in LDL receptor knockout mice.

    PubMed

    Vasandani, Chandna; Kafrouni, Abdallah I; Caronna, Antonella; Bashmakov, Yuriy; Gotthardt, Michael; Horton, Jay D; Spady, David K

    2002-05-01

    We determined the effects of dietary n-6 and n-3 polyunsaturated fatty acids (PUFA) on parameters of plasma lipoprotein and hepatic lipid metabolism in LDL receptor (LDLr) knockout mice. Dietary n-3 PUFA decreased the rate of appearance and increased the hepatic clearance of IDL/LDL resulting in a marked decrease in the plasma concentration of these particles. Dietary n-3 PUFA increased the hepatic clearance of IDL/LDL through a mechanism that appears to involve apolipoprotein (apo)E but is independent of the LDLr, the LDLr related protein (LRP), the scavenger receptor B1, and the VLDLr. The decreased rate of appearance of IDL/VLDL in the plasma of animals fed n-3 PUFA could be attributed to a marked decrease in the plasma concentration of precursor VLDL. Decreased plasma VLDL concentrations were due in part to decreased hepatic secretion of VLDL triglyceride and cholesteryl esters, which in turn was associated with decreased concentrations of these lipids in liver. Decreased hepatic triglyceride concentrations in animals fed n-3 PUFA were due in part to suppression of fatty acid synthesis as a result of a decrease in sterol regulatory element binding protein-1 (SREBP-1) expression and processing. In conclusion, these studies indicate that n-3 PUFA can markedly decrease the plasma concentration of apoB-containing lipoproteins and enhance hepatic LDL clearance through a mechanism that does not involve the LDLr pathway or LRP. PMID:11971949

  2. Secondary radicals derived from chloramines of apolipoprotein B-100 contribute to HOCl-induced lipid peroxidation of low-density lipoproteins.

    PubMed

    Hazell, L J; Davies, M J; Stocker, R

    1999-05-01

    Oxidation of low-density lipoproteins (LDL) is thought to contribute to atherogenesis. Although there is increasing evidence for a role of myeloperoxidase-derived oxidants such as hypochlorite (HOCl), the mechanism by which HOCl modifies LDL remains controversial. Some studies report the protein component to be the major site of attack, whereas others describe extensive lipid peroxidation. The present study addresses this controversy. The results obtained are consistent with the hypothesis that radical-induced oxidation of LDL's lipids by HOCl is a secondary reaction, with most HOCl consumed via rapid, non-radical reaction with apolipoprotein B-100. Subsequent incubation of HOCl-treated LDL gives rise to lipid peroxidation and antioxidant consumption in a time-dependent manner. Similarly, with myeloperoxidase/H2O2/Cl- (the source of HOCl in vivo), protein oxidation is rapid and followed by an extended period of lipid peroxidation during which further protein oxidation does not occur. The secondary lipid peroxidation process involves EPR-detectable radicals, is attenuated by a radical trap or treatment of HOCl-oxidized LDL with methionine, and occurs less rapidly when the lipoprotein was depleted of alpha-tocopherol. The initial reaction of low concentrations of HOCl (400-fold or 800-fold molar excess) with LDL therefore seems to occur primarily by two-electron reactions with side-chain sites on apolipoprotein B-100. Some of the initial reaction products, identified as lysine-residue-derived chloramines, subsequently undergo homolytic (one-electron) reactions to give radicals that initiate antioxidant consumption and lipid oxidation via tocopherol-mediated peroxidation. The identification of these chloramines, and the radicals derived from them, as initiating agents in LDL lipid peroxidation offers potential new targets for antioxidative therapy in atherogenesis. PMID:10215584

  3. C-reactive protein promotes atherosclerosis by increasing LDL transcytosis across endothelial cells

    PubMed Central

    Bian, Fang; Yang, Xiaoyan; Zhou, Fan; Wu, Pin-Hui; Xing, Shasha; Xu, Gao; Li, Wenjing; Chi, Jiangyang; Ouyang, Changhan; Zhang, Yonghui; Xiong, Bin; Li, Yongsheng; Zheng, Tao; Wu, Dan; Chen, Xiaoqian; Jin, Si

    2014-01-01

    Background and Purpose The retention of plasma low-density lipoprotein (LDL) particles in subendothelial space following transcytosis across the endothelium is the initial step of atherosclerosis. Whether or not C-reactive protein (CRP) can directly affect the transcytosis of LDL is not clear. Here we have examined the effect of CRP on transcytosis of LDL across endothelial cells and have explored the underlying mechanisms. Experimental Approach Effects of CRP on transcytosis of FITC-labelled LDL were examined with human umbilical vein endothelial cells and venous rings in vitro and, in vivo, ApoE-/- mice. Laser scanning confocal microscopy, immunohistochemistry and Oil Red O staining were used to assay LDL. Key Results CRP increased transcytosis of LDL. An NADPH oxidase inhibitor, diphenylene iodonium, and the reducing agent, dithiothreitol partly or completely blocked CRP-stimulated increase of LDL transcytosis. The PKC inhibitor, bisindolylmaleimide I and the Src kinase inhibitor, PP2, blocked the trafficking of the molecules responsible for transcytosis. Confocal imaging analysis revealed that CRP stimulated LDL uptake by endothelial cells and vessel walls. In ApoE-/- mice, CRP significantly promoted early changes of atherosclerosis, which were blocked by inhibitors of transcytosis. Conclusions and Implications CRP promoted atherosclerosis by directly increasing the transcytosis of LDL across endothelial cells and increasing LDL retention in vascular walls. These actions of CRP were associated with generation of reactive oxygen species, activation of PKC and Src, and translocation of caveolar or soluble forms of the N-ethylmaleimide-sensitive factor attachment protein. PMID:24517733

  4. Normotriglyceridemic abetalipoproteinemia. absence of the B-100 apolipoprotein.

    PubMed Central

    Malloy, M J; Kane, J P; Hardman, D A; Hamilton, R L; Dalal, K B

    1981-01-01

    In the two genetic forms of abetalipoproteinemia described previously, recessive abetalipoproteinemia and homozygous hypobetalipoproteinemia, all lipoproteins that normally contain apolipoprotein B are absent from plasma. We describe here a new disorder in which normal low density and very low density lipoproteins are absent, but in which triglycerides are absorbed from the intestine and chylomicrons are present in plasma. The underlying molecular defect appears to be selective deletion of the hepatogenous B-100 apolipoprotein. The B-48 apolipoprotein found in chylomicrons is spared. These findings suggest that the two species of apolipoprotein B are under separate genetic control and that low density lipoproteins are not normally derived from chylomicrons. Images PMID:7229035

  5. Kinetic analysis of thermal stability of human low density lipoproteins: a model for LDL fusion in atherogenesis[S

    PubMed Central

    Lu, Mengxiao; Gantz, Donald L.; Herscovitz, Haya; Gursky, Olga

    2012-01-01

    Fusion of modified LDL in the arterial wall promotes atherogenesis. Earlier we showed that thermal denaturation mimics LDL remodeling and fusion, and revealed kinetic origin of LDL stability. Here we report the first quantitative analysis of LDL thermal stability. Turbidity data show sigmoidal kinetics of LDL heat denaturation, which is unique among lipoproteins, suggesting that fusion is preceded by other structural changes. High activation energy of denaturation, Ea = 100 ± 8 kcal/mol, indicates disruption of extensive packing interactions in LDL. Size-exclusion chromatography, nondenaturing gel electrophoresis, and negative-stain electron microscopy suggest that LDL dimerization is an early step in thermally induced fusion. Monoclonal antibody binding suggests possible involvement of apoB N-terminal domain in early stages of LDL fusion. LDL fusion accelerates at pH < 7, which may contribute to LDL retention in acidic atherosclerotic lesions. Fusion also accelerates upon increasing LDL concentration in near-physiologic range, which likely contributes to atherogenesis. Thermal stability of LDL decreases with increasing particle size, indicating that the pro-atherogenic properties of small dense LDL do not result from their enhanced fusion. Our work provides the first kinetic approach to measuring LDL stability and suggests that lipid-lowering therapies that reduce LDL concentration but increase the particle size may have opposite effects on LDL fusion. PMID:22855737

  6. Reduction in lipoprotein-associated apoC-III levels following volanesorsen therapy: phase 2 randomized trial results.

    PubMed

    Yang, Xiaohong; Lee, Sang-Rok; Choi, Yun-Seok; Alexander, Veronica J; Digenio, Andres; Yang, Qingqing; Miller, Yury I; Witztum, Joseph L; Tsimikas, Sotirios

    2016-04-01

    Elevated apoC-III levels predict increased cardiovascular risk when present on LDL and HDL particles. We developed novel high-throughput chemiluminescent ELISAs that capture apoB, lipoprotein (a) [Lp(a)], and apoA-I in plasma and then detect apoC-III on these individual lipoproteins as apoCIII-apoB, apoCIII-Lp(a), and apoCIII-apoAI complexes, respectively. We assessed the effects on these complexes of placebo or 100-300 mg volanesorsen, a generation 2.0+ antisense drug that targets apoC3 mRNA in patients with hypertriglyceridemia, including familial chylomicronemia syndrome (n = 3), volanesorsen monotherapy (n = 51), and as add-on to fibrate (n = 26), treated for 85 days and followed for 176 days. Compared with placebo, volanesorsen was associated with an 82.3 ± 11.7%, 81.3 ± 15.7%, and 80.8 ± 13.6% reduction in apoCIII-apoB, apoCIII-Lp(a), and apoCIII-apoA-I, respectively (300 mg dose;P< 0.001 for all), at day 92. Strong correlations in all assay measures were noted with total plasma apoC-III, chylomicron-apoC-III, and VLDL-apoC-III. In conclusion, novel high-throughput ELISAs were developed to detect lipoprotein-associated apoC-III, including for the first time on Lp(a). Volanesorsen uniformly lowers apoC-III on apoB-100, Lp(a), and apoA-I lipoproteins, and may be a potent agent to reduce triglycerides and cardiovascular risk mediated by apoC-III. PMID:26848137

  7. Hepatic Endosome Protein Profiling in Apolipoprotein E Deficient Mice Expressing Apolipoprotein B48 but not B100

    PubMed Central

    Chen, AnShu; Guo, ZhongMao; Zhou, LiChun; Yang, Hong

    2011-01-01

    Liver cells absorb apolipoprotein (Apo) B48-carrying lipoproteins in ApoE’s absence, albeit not as efficiently as the ApoE-mediated process. Our objective was to identify differentially expressed hepatic endosome proteins in mice expressing ApoB48 but lacking ApoE and ApoB100 expression (ApoE−/−/B48/48). We purified early and late endosomes from ApoE−/−/B48/48 and wild-type mouse’s livers. In ApoE−/−/B48/48 mouse’s hepatic endosomes, proteomic analysis revealed elevated protein levels of major urinary protein 6 (MUP), calreticulin, protein disulfide isomerases (PDI) A1, and A3. These proteins are capable of interacting with lipids/lipoproteins and triggering receptor-mediated endocytosis. In addition, hepatic endosomes from ApoE−/− /B48/48 mice exhibited significantly reduced protein levels of haptoglobin, hemopexin, late endosome/lysosome interacting protein, cell division control protein 2 homolog, γ-soluble Nethylmaleimide- sensitive factor attachment protein, vacuolar ATP synthase catalytic subunit A1, dipeptidyl peptidases II, cathepsin B, D, H, and Z. These proteins participate in plasma heme clearance, receptor-mediated signaling, membrane fusion, endosomal/lysosomal acidification, and protein degradation. The significance of increasing endosomal MUP, calreticulin and PDIs in ApoE−/−/B48/48 mouse liver cells is not clear; however, reducing endosomal/ lysosomal membrane proteins and hydrolases might be, at least partially, responsible for the retarded clearance of plasma ApoB-carrying lipoproteins in ApoE−/−/B48/48 mice. PMID:21837265

  8. Common and Rare Gene Variants Affecting Plasma LDL Cholesterol

    PubMed Central

    Burnett, John R; Hooper, Amanda J

    2008-01-01

    The plasma level of LDL cholesterol is clinically important and genetically complex. LDL cholesterol levels are in large part determined by the activity of LDL receptors (LDLR) in the liver. Autosomal dominant familial hypercholesterolaemia (FH) – with its high LDL cholesterol levels, xanthomas, and premature atherosclerosis – is caused by mutations in either the LDLR or in APOB – the protein in LDL recognised by the LDLR. A third, rare form – autosomal recessive hypercholesterolaemia – arises from mutations in the gene encoding an adaptor protein involved in the internalisation of the LDLR. A fourth variant of inherited hypercholesterolaemia was recently found to be associated with missense mutations in PCSK9, which encodes a serine protease that degrades LDLR. Whereas the gain-of-function mutations in PCSK9 are rare, a spectrum of more frequent loss-of-function mutations in PCSK9 associated with low LDL cholesterol levels has been identified in selected populations and could protect against coronary heart disease. Heterozygous familial hypobetalipoproteinaemia (FHBL) – with its low LDL cholesterol levels and resistance to atherosclerosis – is caused by mutations in APOB. In contrast to other inherited forms of severe hypocholesterolaemia such as abetalipoproteinaemia - caused by mutations in MTP - and homozygous FHBL, a deficiency of PCSK9 appears to be benign. Rare variants of NPC1L1, the gene encoding the putative intestinal cholesterol receptor, have shown more modest effects on plasma LDL cholesterol than PCSK9 variants, similar in magnitude to the effect of common APOE variants. Taken together, these findings indicate that heritable variation in plasma LDL cholesterol is conferred by sequence variation in various loci, with a small number of common and multiple rare gene variants contributing to the phenotype. PMID:18566665

  9. A Study of the Extended Lipid Profile including Oxidized LDL, Small Dense LDL, Lipoprotein (a) and Apolipoproteins in the Assessment of Cardiovascular Risk in Hypothyroid Patients

    PubMed Central

    Bansal, Sanjiv Kumar

    2016-01-01

    Introduction Hypothyroidism is one of the most common metabolic disorders associated with dyslipidemia which poses a higher risk of Coronary Artery Disease (CAD) in such patients. Biochemical markers which can pick up the risk promptly are becoming imperative now-a-days and thus the assessment beyond the conventional lipid profile is the need of the hour. Aims To assess the association of non-conventional lipid parameters like small dense Low Density Lipoprotein (sd LDL), oxidized Low Density Lipoprotein (ox LDL), Apolipoprotein A (Apo A1), Apolipoprotein B (Apo B) and Lipoprotein (a) {Lp(a)} in hypothyroid patients and compare their values with the conventional lipid parameters such as Total Cholesterol (TC), Triglyceride (TG), Low-Density Lipoprotein Cholesterol (LDL-C) and High-Density Lipoprotein Cholesterol (HDL-C). Materials and Methods One hundred and thirty clinically proven patients of hypothyroidism aged 20-60 years and equal number of age and gender matched healthy individuals were included in this case control study. Serum sd LDL, ox LDL, Apo A1, Apo B, Lp (a), lipid profile, Thyroid Stimulating Hormone (TSH), Free Triiodothyronine (FT3) and Free Tetraiodothyronine (FT4) levels were measured in both the groups. The data was recorded and analysed on SPSS system. The results of cases and controls were compared by student t-test and one-way ANOVA. All the parameters were correlated with TSH by Pearson’s correlation. Results We found significantly high levels of sd LDL, ox LDL, Apo B, Lp (a), TC, TG, LDL-C in cases as compared to the controls. Ox LDL has shown maximum correlation with serum TSH (p<0.0001, r=0.801) followed by sd LDL (p<0.0001, r=0.792), Apo B (p<0.001, r=0.783) and LDL-C (p<0.001, r=0.741). Moreover, ox LDL and sd LDL were found to be increased in normolipidemic hypothyroid patients thereby giving a strong supportive evidence that estimation of these parameters can become fundamental in prompt identification of the high risk patients of

  10. Novel mutations of APOB cause ApoB truncations undetectable in plasma and familial hypobetalipoproteinemia.

    PubMed

    Yue, Pin; Yuan, Bo; Gerhard, Daniela S; Neuman, Rosalind J; Isley, William L; Harris, William S; Schonfeld, Gustav

    2002-08-01

    Familial hypobetalipoproteinemia (FHBL) is a genetic disorder characterized by low levels of apoB-100 and LDL cholesterol. Truncation-producing mutations of apoB (chromosome 2) are among several potential causes of FHBL in patients. Ten new families with FHBL linked to chromosome 2 were identified. In Family 8, a 4432delT in exon 26 produces a frame-shift and a premature stop codon predicted to produce a truncated apoB-30.9. Even though this truncation is just 10 amino acid shorter than the well-documented apoB-31, which is readily detectable in plasma, apoB-30.9 is undetectable. Most truncations shorter than apoB-30 are not detectable in plasma. In Family 34, an acceptor splicing mutation at position -1 of exon 14 changes the acceptor splice site AG to AA. Two families (Family 50 and 52) had mutations (apoB-9 and apoB-29) reported previously. In Family 98, a novel point mutation in exon 26 (11163T>G) causes a premature stop codon, and produces a truncated apoB-80.5 readily detectable in plasma. Sequencing of the ApoB gene in families 1, 5, 18, 58, and 59 did not reveal mutations. PMID:12124991

  11. Synthetic LDL as targeted drug delivery vehicle

    SciTech Connect

    Forte, Trudy M.; Nikanjam, Mina

    2012-08-28

    The present invention provides a synthetic LDL nanoparticle comprising a lipid moiety and a synthetic chimeric peptide so as to be capable of binding the LDL receptor. The synthetic LDL nanoparticle of the present invention is capable of incorporating and targeting therapeutics to cells expressing the LDL receptor for diseases associated with the expression of the LDL receptor such as central nervous system diseases. The invention further provides methods of using such synthetic LDL nanoparticles.

  12. Atheroprotective Effect of Oleoylethanolamide (OEA) Targeting Oxidized LDL

    PubMed Central

    Wu, Huijuan; Li, Long; Huang, Rui; Zhu, Yueyong; Qiu, Yan; Fu, Jin; Ren, Jie; Zhu, Chenggang

    2014-01-01

    Dietary fat-derived lipid oleoylethanolamide (OEA) has shown to modulate lipid metabolism through a peroxisome proliferator-activated receptor-alpha (PPAR-α)-mediated mechanism. In our study, we further demonstrated that OEA, as an atheroprotective agent, modulated the atherosclerotic plaques development. In vitro studies showed that OEA antagonized oxidized LDL (ox-LDL)-induced vascular endothelial cell proliferation and vascular smooth muscle cell migration, and suppressed lipopolysaccharide (LPS)-induced LDL modification and inflammation. In vivo studies, atherosclerosis animals were established using balloon-aortic denudation (BAD) rats and ApoE-/- mice fed with high-caloric diet (HCD) for 17 or 14 weeks respectively, and atherosclerotic plaques were evaluated by oil red staining. The administration of OEA (5 mg/kg/day, intraperitoneal injection, i.p.) prevented or attenuated the formation of atherosclerotic plaques in HCD-BAD rats or HCD-ApoE−/− mice. Gene expression analysis of vessel tissues from these animals showed that OEA induced the mRNA expressions of PPAR-α and downregulated the expression of M-CFS, an atherosclerotic marker, and genes involved in oxidation and inflammation, including iNOS, COX-2, TNF-α and IL-6. Collectively, our results suggested that OEA exerted a pharmacological effect on modulating atherosclerotic plaque formation through the inhibition of LDL modification in vascular system and therefore be a potential candidate for anti-atherosclerosis drug. PMID:24465540

  13. Atheroprotective effect of oleoylethanolamide (OEA) targeting oxidized LDL.

    PubMed

    Fan, Angran; Wu, Xiaofeng; Wu, Huijuan; Li, Long; Huang, Rui; Zhu, Yueyong; Qiu, Yan; Fu, Jin; Ren, Jie; Zhu, Chenggang

    2014-01-01

    Dietary fat-derived lipid oleoylethanolamide (OEA) has shown to modulate lipid metabolism through a peroxisome proliferator-activated receptor-alpha (PPAR-α)-mediated mechanism. In our study, we further demonstrated that OEA, as an atheroprotective agent, modulated the atherosclerotic plaques development. In vitro studies showed that OEA antagonized oxidized LDL (ox-LDL)-induced vascular endothelial cell proliferation and vascular smooth muscle cell migration, and suppressed lipopolysaccharide (LPS)-induced LDL modification and inflammation. In vivo studies, atherosclerosis animals were established using balloon-aortic denudation (BAD) rats and ApoE(-/-) mice fed with high-caloric diet (HCD) for 17 or 14 weeks respectively, and atherosclerotic plaques were evaluated by oil red staining. The administration of OEA (5 mg/kg/day, intraperitoneal injection, i.p.) prevented or attenuated the formation of atherosclerotic plaques in HCD-BAD rats or HCD-ApoE(-/-) mice. Gene expression analysis of vessel tissues from these animals showed that OEA induced the mRNA expressions of PPAR-α and downregulated the expression of M-CFS, an atherosclerotic marker, and genes involved in oxidation and inflammation, including iNOS, COX-2, TNF-α and IL-6. Collectively, our results suggested that OEA exerted a pharmacological effect on modulating atherosclerotic plaque formation through the inhibition of LDL modification in vascular system and therefore be a potential candidate for anti-atherosclerosis drug. PMID:24465540

  14. Association of Apolipoprotein B, LDL-C and vascular stiffness in Adolescents with Type 1 Diabetes

    PubMed Central

    Bjornstad, Petter; Nguyen, Nhung; Reinick, Christina; Maahs, David M.; Bishop, Franziska K.; Clements, Scott A.; Snell-Bergeon, Janet K.; Lieberman, Rachel; Pyle, Laura P.; Daniels, Stephen R.; Wadwa, R. Paul

    2014-01-01

    Objective LDL cholesterol (LDL-C) is the current lipid standard for cardiovascular disease (CVD) risk assessment in type 1 diabetes. Apolipoprotein B (apoB) may be helpful to further stratify CVD-risk. We explored the association between apoB and pulse wave velocity (PWV) to determine if apoB would improve CVD-risk stratification, especially in type 1 diabetes adolescents with borderline LDL-C (100-129mg/dL). We hypothesized that type 1 diabetes adolescents with borderline LDL-C and elevated apoB (≥90mg/dL) would have increased PWV compared to those with borderline LDL-C and normal apoB (<90mg/dL), and that apoB would explain more of the variability of PWV than alternative lipid indices. Methods Fasting lipids, including apoB, were collected in 267 adolescents, age 12-19 years, with diabetes-duration >5 years and HbA1c 8.9±1.6%. Triglyceride to HDL-C ratio (TG/HDL-C) and nonHDL-cholesterol (nonHDL-C) were calculated. PWV was measured in the carotid-femoral segment. Results ApoB, nonHDL-C and TG/HDL-C correlated with PWV (p<0.0001). ApoB, nonHDL-C and TG/HDL-C remained significantly associated with PWV in fully-adjusted models. In adolescents with borderline LDL-C (n=61), PWV was significantly higher in those with elevated apoB than in those with normal apoB (5.6±0.6 vs. 5.2±0.6m/s, p<0.01), and also remained significant after adjustment for CVD-risk factors (p=0.0002). Moreover, in those with borderline LDL-C, apoB explained more of the variability of PWV than nonHDL-C and TG/HDL-C. Conclusion Elevated apoB is associated with increased arterial stiffness in type 1 diabetes adolescents. Measurement of apoB in addition to LDL-C may be helpful in stratifying CVD-risk in type 1 diabetes adolescents, especially in those with borderline LDL-C. PMID:25539881

  15. APOE Genotyping, Cardiovascular Disease

    MedlinePlus

    ... Risk Assessment ; HDL Cholesterol ; LDL Cholesterol ; Lipid Profile ; Triglycerides Were you looking instead for APOE genotyping ordered ... the skin called xanthomas, a high level of triglycerides in the blood, and atherosclerosis that develops at ...

  16. ox-LDL induces endothelial dysfunction by promoting Arp2/3 complex expression.

    PubMed

    Tang, Yao; Zhao, Jianting; Shen, Liming; Jin, Yiqi; Zhang, Zhixuan; Xu, Guoxiong; Huang, Xianchen

    2016-06-24

    Oxidized low-density lipoproteins (ox-LDL) play a critical role in endothelial injury including cytoskeleton reorganization, which is closely related to actin-related protein 2/3 (Arp2/3) complex. The aim of this study was to investigate the role of Arp2/3 complex in ox-LDL-induced endothelial dysfunction. In this study, we found that Arp2 and Arp3 expression was increased under atherosclerotic conditions both in ApoE-/- mice and in ox-LDL-stimulated human coronary artery endothelial cells (HCAECs). Arp2/3 complex inhibitor CK666 significantly reduced ox-LDL-induced ROS generation and cytoskeleton reorganization, and increased NO release in HCAECs. Pretreatment with LOX-1- but not CD36-blocking antibody markedly decreased ox-LDL-induced Arp2 and Arp3 expression. Moreover, Rac-1 siRNA remarkably suppressed ox-LDL-stimulated Arp2 and Arp3 expression. Additionally, CK666 reduced endothelial nitric oxide synthase (eNOS) expression and atherosclerotic lesions in ApoE-/- mice. Collectively, ox-LDL induces endothelial dysfunction by activating LOX-1/Rac-1 signaling and upregulating Arp2/3 complex expression. PMID:27181356

  17. Selective uptake and efflux of cholesteryl linoleate in LDL by macrophages expressing 12/15-lipoxygenase

    SciTech Connect

    Takahashi, Yoshitaka . E-mail: ytaka@fhw.oka-pu.ac.jp; Zhu, Hong; Xu, Wanpeng; Murakami, Takashi; Iwasaki, Tadao; Hattori, Hiroaki; Yoshimoto, Tanihiro

    2005-12-09

    Oxidation of low density lipoprotein (LDL) is a critical step for airtightness, and the role of the 12/15-lipoxygenase (12/15-Lox) as well as LDL receptor-related protein (Lp) expressed in macrophages in this process has been suggested. The oxygenation of cholesteryl linoleate in LDL by mouse macrophage-like Joe.1 cells over expressing 12/15-Lox was inhibited by an anti-Lp antibody but not by an anti-LDL receptor antibody. When the cells were incubated with LDL double-labeled by [{sup 3}H]cholesteryl linoleate and [{sup 125}I]apo B, association with the cells of [{sup 3}H]cholesteryl linoleate expressed as LDL protein equivalent exceeded that of [{sup 125}I]apo B, indicating selective uptake of [{sup 3}H]cholesteryl linoleate from LDL to these cells. An anti-Lp antibody inhibited the selective uptake of [{sup 3}H]cholesteryl ester by 62% and 81% with the 12/15-Lox-expressing cells and macrophages, respectively. Furthermore, addition of LDL to the culture medium of the [{sup 3}H]cholesteryl linoleate-labeled 12/15-Lox-expressing cells increased the release of [{sup 3}H]cholesteryl linoleate to the medium in LDL concentration- and time-dependent manners. The transport of [{sup 3}H]cholesteryl linoleate from the cells to LDL was also inhibited by an anti-Lp antibody by 75%. These results strongly suggest that Lp contributes to the LDL oxidation by 12/15-Lox in macrophages by selective uptake and efflux of cholesteryl ester in the LDL particle.

  18. Secreted apolipoprotein E reduces macrophage-mediated LDL oxidation in an isoform-dependent way.

    PubMed

    Mabile, Laurence; Lefebvre, Chantal; Lavigne, Jacques; Boulet, Lucie; Davignon, Jean; Lussier-Cacan, Suzanne; Bernier, Lise

    2003-11-01

    As an inflammatory cell, the macrophage produces various oxidizing agents, such as free radical species. These can modify LDL as a secondary effect and doing so may favor atherogenic processes. Any molecule able to counteract these reactions would be of much benefit, especially if secreted by the macrophage itself at the lesion site. Such is the case for apolipoprotein E (apoE), which has been shown to exert antioxidant properties in some studies, mostly in relation to Alzheimer's disease. In this study, we assessed the antioxidant potential of the various isoforms of apoE (E2, E3, and E4) using a metal-induced LDL oxidation system with exogenous recombinant apoE and an in vitro model of macrophage-mediated LDL oxidation. We found that all three isoforms had an antioxidant capacity. However, whereas apoE2 was the most protective isoform in the cell-free system, the opposite was observed in apoE-transfected J774 macrophages. In the latter model, cellular cholesterol efflux was found to be more important with apoE2, possibly explaining the larger quantity of oxidative indices observed in the medium. It is proposed that the antioxidant property of apoE results from a balance between direct apoE antioxidant capacities, such as the ability to trap free radicals, and potentially pro-oxidative indirect events associated with cholesterol efflux from cells. Our observations add to the therapeutic potential of apoE. However, they also suggest the need for more experiments in order to achieve careful selection of the apoE isoform to be targeted, especially in the perspective of apoE transgene use. PMID:14587032

  19. Serum apolipoprotein B-100 concentration predicts the virological response to pegylated interferon plus ribavirin combination therapy in patients infected with chronic hepatitis C virus genotype 1b.

    PubMed

    Yoshizawa, Kai; Abe, Hiroshi; Aida, Yuta; Ishiguro, Haruya; Ika, Makiko; Shimada, Noritomo; Tsubota, Akihito; Aizawa, Yoshio

    2013-07-01

    Host lipoprotein metabolism is associated closely with the life cycle of hepatitis C virus (HCV), and serum lipid profiles have been linked to the response to pegylated interferon (Peg-IFN) plus ribavirin (RBV) therapy. Polymorphisms in the human IL28B gene and amino acid substitutions in the core and interferon sensitivity-determining region (ISDR) in NS5A of HCV genotype 1b (G1b) were also shown to strongly affect the outcome of Peg-IFN plus RBV therapy. In this study, an observational cohort study was performed in 247 HCV G1b-infected patients to investigate whether the response to Peg-IFN and RBV combination therapy in these patients is independently associated with the level of lipid factors, especially apolipoprotein B-100 (apoB-100), an obligatory structural component of very low density lipoprotein and low density lipoprotein. The multivariate logistic analysis subsequently identified apoB-100 (odds ratio (OR), 1.602; 95% confidence interval (CI), 1.046-2.456), alpha-fetoprotein (OR, 0.764; 95% CI, 0.610-0.958), non-wild-type ISDR (OR, 5.617; 95% CI, 1.274-24.754), and the rs8099917 major genotype (OR, 34.188; 95% CI, 10.225-114.308) as independent factors affecting rapid initial virological response (decline in HCV RNA levels by ≥3-log10 at week 4). While lipid factors were not independent predictors of complete early or sustained virological response, the serum apoB-100 level was an independent factor for sustained virological response in patients carrying the rs8099917 hetero/minor genotype. Together, we conclude that serum apoB-100 concentrations could predict virological response to Peg-IFN plus RBV combination therapy in patients infected with HCV G1b, especially in those with the rs8099917 hetero/minor genotype. PMID:23918536

  20. Relationship of IgG and IgM autoantibodies and immune complexes to oxidized LDL with markers of oxidation and inflammation and cardiovascular events: results from the EPIC-Norfolk Study.

    PubMed

    Ravandi, Amir; Boekholdt, S Matthijs; Mallat, Ziad; Talmud, Philippa J; Kastelein, John J P; Wareham, Nicholas J; Miller, Elizabeth R; Benessiano, Joelle; Tedgui, Alain; Witztum, Joseph L; Khaw, Kay-Tee; Tsimikas, Sotirios

    2011-10-01

    Levels of IgG and IgM autoantibodies (AA) to malondialdehyde (MDA)-LDL and apoB-immune complexes (ICs) were measured in 748 cases and 1,723 controls in the EPIC-Norfolk cohort and their association to coronary artery disease (CAD) events determined. We evaluated whether AA and IC modify CAD risk associated with secretory phospholipase A(2) (sPLA(2)) type IIA mass and activity, lipoprotein-associated PLA(2) activity, lipoprotein (a) [Lp(a)], oxidized phospholipids on apoB-100 (OxPL/apoB), myeloperoxidase, and high sensitivity C-reactive protein. IgG ICs were higher in cases versus controls (P = 0.02). Elevated levels of IgM AA and IC were inversely associated with Framingham Risk Score and number of metabolic syndrome criteria (p range 0.02-0.001). In regression analyses adjusted for age, smoking, diabetes, LDL-cholesterol, HDL-cholesterol, and systolic blood pressure, the highest tertiles of IgG and IgM AA and IC were not associated with higher risk of CAD events compared with the lowest tertiles. However, elevated levels of IgM IC reduced the risk of Lp(a) (P = 0.006) and elevated IgG MDA-LDL potentiated the risk of sPLA(2) mass (P = 0.018). This epidemiological cohort of initially healthy subjects shows that IgG and IgM AA and IC are not independent predictors of CAD events but may modify CAD risk associated with elevated levels of oxidative biomarkers. PMID:21821825

  1. Simvastatin Efficiently Lowers Small LDL-IgG Immune Complex Levels: A Therapeutic Quality beyond the Lipid-Lowering Effect.

    PubMed

    Hörl, Gerd; Froehlich, Harald; Ferstl, Ulrika; Ledinski, Gerhard; Binder, Josepha; Cvirn, Gerhard; Stojakovic, Tatjana; Trauner, Michael; Koidl, Christoph; Tafeit, Erwin; Amrein, Karin; Scharnagl, Hubert; Jürgens, Günther; Hallström, Seth

    2016-01-01

    We investigated a polyethylene glycol non-precipitable low-density lipoprotein (LDL) subfraction targeted by IgG and the influence of statin therapy on plasma levels of these small LDL-IgG-immune complexes (LDL-IgG-IC). LDL-subfractions were isolated from 6 atherosclerotic subjects and 3 healthy individuals utilizing iodixanol density gradient ultracentrifugation. Cholesterol, apoB and malondialdehyde (MDA) levels were determined in each fraction by enzymatic testing, dissociation-enhanced lanthanide fluorescence immunoassay and high-performance liquid chromatography, respectively. The levels of LDL-IgG-IC were quantified densitometrically following lipid electrophoresis, particle size distribution was assessed with dynamic light scattering and size exclusion chromatography. The influence of simvastatin (40 mg/day for three months) on small LDL-IgG-IC levels and their distribution among LDL-subfractions (salt gradient separation) were investigated in 11 patients with confirmed coronary artery disease (CAD). We demonstrate that the investigated LDL-IgG-IC are small particles present in atherosclerotic patients and healthy subjects. In vitro assembly of LDL-IgG-IC resulted in particle density shifts indicating a composition of one single molecule of IgG per LDL particle. Normalization on cholesterol levels revealed MDA values twice as high for LDL-subfractions rich in small LDL-IgG-IC if compared to dominant LDL-subfractions. Reactivity of affinity purified small LDL-IgG-IC to monoclonal antibody OB/04 indicates a high degree of modified apoB and oxidative modification. Simvastatin therapy studied in the CAD patients significantly lowered LDL levels and to an even higher extent, small LDL-IgG-IC levels without affecting their distribution. In conclusion simvastatin lowers levels of small LDL-IgG-IC more effectively than LDL-cholesterol and LDL-apoB levels in atherosclerotic patients. This antiatherogenic effect may additionally contribute to the known beneficial

  2. Simvastatin Efficiently Lowers Small LDL-IgG Immune Complex Levels: A Therapeutic Quality beyond the Lipid-Lowering Effect

    PubMed Central

    Ferstl, Ulrika; Ledinski, Gerhard; Binder, Josepha; Cvirn, Gerhard; Stojakovic, Tatjana; Trauner, Michael; Koidl, Christoph; Tafeit, Erwin; Amrein, Karin; Scharnagl, Hubert; Jürgens, Günther; Hallström, Seth

    2016-01-01

    We investigated a polyethylene glycol non-precipitable low-density lipoprotein (LDL) subfraction targeted by IgG and the influence of statin therapy on plasma levels of these small LDL-IgG-immune complexes (LDL-IgG-IC). LDL-subfractions were isolated from 6 atherosclerotic subjects and 3 healthy individuals utilizing iodixanol density gradient ultracentrifugation. Cholesterol, apoB and malondialdehyde (MDA) levels were determined in each fraction by enzymatic testing, dissociation-enhanced lanthanide fluorescence immunoassay and high-performance liquid chromatography, respectively. The levels of LDL-IgG-IC were quantified densitometrically following lipid electrophoresis, particle size distribution was assessed with dynamic light scattering and size exclusion chromatography. The influence of simvastatin (40 mg/day for three months) on small LDL-IgG-IC levels and their distribution among LDL-subfractions (salt gradient separation) were investigated in 11 patients with confirmed coronary artery disease (CAD). We demonstrate that the investigated LDL-IgG-IC are small particles present in atherosclerotic patients and healthy subjects. In vitro assembly of LDL-IgG-IC resulted in particle density shifts indicating a composition of one single molecule of IgG per LDL particle. Normalization on cholesterol levels revealed MDA values twice as high for LDL-subfractions rich in small LDL-IgG-IC if compared to dominant LDL-subfractions. Reactivity of affinity purified small LDL-IgG-IC to monoclonal antibody OB/04 indicates a high degree of modified apoB and oxidative modification. Simvastatin therapy studied in the CAD patients significantly lowered LDL levels and to an even higher extent, small LDL-IgG-IC levels without affecting their distribution. In conclusion simvastatin lowers levels of small LDL-IgG-IC more effectively than LDL-cholesterol and LDL-apoB levels in atherosclerotic patients. This antiatherogenic effect may additionally contribute to the known beneficial

  3. Association between small dense LDL and sub-clinical atherosclerosis in patients with psoriatic arthritis.

    PubMed

    Gentile, Marco; Peluso, Rosario; Di Minno, Matteo Nicola Dario; Costa, Luisa; Caso, Francesco; de Simone, Biagio; Iannuzzo, Gabriella; Scarpa, Raffaele; Rubba, Paolo

    2016-08-01

    Psoriatic arthritis (PsA) is an inflammatory rheumatic disorder occurring in patients with psoriasis. Several studies have shown an association between Psa and traditional atherosclerotic risk factors. We evaluated the relationship between small dense low-density lipoproteins particles (sd-LDL) a risk marker for atherosclerosis, sub-clinical atherosclerosis and PsA in a group of 50 patients with PsA and in 100 controls. Cholesterol, high-density lipoproteins (HDL), low-density lipoproteins (LDL), triglycerides, insulin, homeostasis model assessment (HOMA), Apo B, and sd-LDL have been measured. LDL particle separation was performed and seven LDL subfractions were obtained, LDL score (percentage of sd-LDL) and mean LDL particle size were calculated. PsA patients and control group differ significantly (p < 0.001) in triglycerides values (119.3 ± 52.0 vs 90.7 ± 40.7 mg/dL), Apo B (1.1 ± 0.2 vs 0.9 ± 0.1 g/L), insulin (8.9 ± 4.9 vs 5.8 ± 3.2 mU/L), HOMA (2.2 ± 1.7 vs 1.3 ± 0.8), BMI (27.7 ± 3.3 vs 25.8 ± 3.8). LDL score is significantly higher in PsA as compared to control (9.0 ± 10.7 vs 2.9 ± 4.7 mg/dL); and mean LDL size is significantly lower in PsA than control (268.1 ± 4.6 vs 271.2 ± 2.7 Å). These differences were confirmed when stratifying PsA patients for treatment and for disease activity. LDL score and LDL diameter significantly were correlated with the carotid IMT in patients with PsA. These findings show a novel relationship between LDL score and mean LDL size with PsA diagnosis and with sub-clinical atherosclerosis. Sd-LDL gives potentially useful information in the risk assessment for atherosclerotic disease in PsA patients. PMID:27411815

  4. Apolipoprotein B but not LDL Cholesterol Is Associated With Coronary Artery Calcification in Type 2 Diabetic Whites

    PubMed Central

    Martin, Seth S.; Qasim, Atif N.; Mehta, Nehal N.; Wolfe, Megan; Terembula, Karen; Schwartz, Stanley; Iqbal, Nayyar; Schutta, Mark; Bagheri, Roshanak; Reilly, Muredach P.

    2009-01-01

    OBJECTIVE Evidence favors apolipoprotein B (apoB) over LDL cholesterol as a predictor of cardiovascular events, but data are lacking on coronary artery calcification (CAC), especially in type 2 diabetes, where LDL cholesterol may underestimate atherosclerotic burden. We investigated the hypothesis that apoB is a superior marker of CAC relative to LDL cholesterol. RESEARCH DESIGN AND METHODS We performed cross-sectional analyses of white subjects in two community-based studies: the Penn Diabetes Heart Study (N = 611 type 2 diabetic subjects, 71.4% men) and the Study of Inherited Risk of Coronary Atherosclerosis (N = 803 nondiabetic subjects, 52.8% men) using multivariate analysis of apoB and LDL cholesterol stratified by diabetes status. RESULTS In type 2 diabetes, apoB was associated with CAC after adjusting for age, sex, and medications [Tobit regression ratio of increased CAC for 1-SD increase in apoB; 1.36 (95% CI 1.06–1.75), P = 0.016] whereas LDL cholesterol was not [1.09 (0.85–1.41)]. In nondiabetic subjects, both were associated with CAC [apoB 1.65 (1.38–1.96), P < 0.001; LDL cholesterol 1.56 (1.30–1.86), P < 0.001]. In combined analysis of diabetic and nondiabetic subjects, apoB provided value in predicting CAC scores beyond LDL cholesterol, total cholesterol, the total cholesterol/HDL cholesterol and triglyceride/HDL cholesterol ratios, and marginally beyond non-HDL cholesterol. CONCLUSIONS Plasma apoB, but not LDL cholesterol, levels were associated with CAC scores in type 2 diabetic whites. ApoB levels may be particularly useful in assessing atherosclerotic burden and cardiovascular risk in type 2 diabetes. PMID:19491209

  5. Mutilocus genetic determinants of LDL particle size in coronary artery disease families

    SciTech Connect

    Rotter, J.I.; Bu, X.; Cantor, R.M.

    1996-03-01

    Recent interest in atherosclerosis has focused on the genetic determinants of low-density lipoprotein (LDL) particle size, because of (1) the association of small dense LDL particles with a three-fold increased risk for coronary artery disease (CAD) and (2) the recent report of linkage of the trait to the LDL receptor (chromosome 19). By utilizing nonparametric quantitative sib-pair and relative-pair-analysis methods in CAD families, we tested for linkage of a gene or genes controlling LDL particle sizes with the genetic loci for the major apolipoproteins and enzymes participating in lipoprotein metabolism. We confirmed evidence for linkage to the LDL receptor locus (P = .008). For six candidate gene loci, including apolipoprotein(apo)B, apoAII, apo(a), apoE-CI-CII, lipoprotein lipase, and high-density lipoprotein-binding protein, no evidence for linkage was observed by sib-pair linkage analyses (P values ranged from .24 to .81). However, in addition, we did find tentative evidence for linkage with the apoAI-CIII-AIV locus (chromosome 11) (P = .06) and significant evidence for linkage of the cholesteryl ester transfer protein locus (chromosome 16) (P = .01) and the manganese superoxide dismutase locus (chromosome 6) (P = .001), thus indicating multilocus determination of this atherogenic trait. 73 refs., 3 figs., 4 tabs.

  6. 12 CFR 563b.100 - What must I do before a conversion?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... FROM MUTUAL TO STOCK FORM Standard Conversions Prior to Conversion § 563b.100 What must I do before a... for conversion. OTS will discuss the information that you must include in the application...

  7. 12 CFR 563b.100 - What must I do before a conversion?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... FROM MUTUAL TO STOCK FORM Standard Conversions Prior to Conversion § 563b.100 What must I do before a... for conversion. OTS will discuss the information that you must include in the application...

  8. 12 CFR 563b.100 - What must I do before a conversion?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... FROM MUTUAL TO STOCK FORM Standard Conversions Prior to Conversion § 563b.100 What must I do before a... for conversion. OTS will discuss the information that you must include in the application...

  9. 12 CFR 563b.100 - What must I do before a conversion?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... FROM MUTUAL TO STOCK FORM Standard Conversions Prior to Conversion § 563b.100 What must I do before a... for conversion. OTS will discuss the information that you must include in the application...

  10. 12 CFR 563b.100 - What must I do before a conversion?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... FROM MUTUAL TO STOCK FORM Standard Conversions Prior to Conversion § 563b.100 What must I do before a... for conversion. OTS will discuss the information that you must include in the application...

  11. A combined LDL receptor/LDL receptor adaptor protein 1 mutation as the cause for severe familial hypercholesterolemia.

    PubMed

    Soufi, Muhidien; Rust, Stephan; Walter, Michael; Schaefer, Juergen R

    2013-05-25

    Familial hypercholesterolemia (FH) results from impaired catabolism of plasma low density lipoproteins (LDL), thus leading to high cholesterol, atherosclerosis, and a high risk of premature myocardial infarction. FH is commonly caused by defects of the LDL receptor or its main ligand apoB, together mediating cellular uptake and clearance of plasma LDL. In some cases FH is inherited by mutations in the genes of PCSK9 and LDLRAP1 (ARH) in a dominant or recessive trait. The encoded proteins are required for LDL receptor stability and internalization within the LDLR pathway. To detect the underlying genetic defect in a family of Turkish descent showing unregular inheritance of severe FH, we screened the four candidate genes by denaturing gradient gel electrophoresis (DGGE) mutation analysis. We identified different combinatory mixtures of LDLR- and LDLRAP1-gene defects as the cause for severe familial hypercholesterolemia in this family. We also show for the first time that a heterozygous LDLR mutation combined with a homozygous LDLRAP1 mutation produces a more severe hypercholesterolemia phenotype in the same family than a homozygous LDLR mutation alone. PMID:23510778

  12. Differential Trafficking of Oxidized LDL and Oxidized LDL Immune Complexes in Macrophages: Impact on Oxidative Stress

    PubMed Central

    Al Gadban, Mohammed M.; Smith, Kent J.; Soodavar, Farzan; Piansay, Christabelle; Chassereau, Charlyne; Twal, Waleed O.; Klein, Richard L.; Virella, Gabriel; Lopes-Virella, Maria F.; Hammad, Samar M.

    2010-01-01

    Background Oxidized low-density lipoproteins (oxLDL) and oxLDL-containing immune complexes (oxLDL-IC) contribute to formation of lipid-laden macrophages (foam cells). It has been shown that oxLDL-IC are considerably more efficient than oxLDL in induction of foam cell formation, inflammatory cytokines secretion, and cell survival promotion. Whereas oxLDL is taken up by several scavenger receptors, oxLDL-IC are predominantly internalized through the FCγ receptor I (FCγ RI). This study examined differences in intracellular trafficking of lipid and apolipoprotein moieties of oxLDL and oxLDL-IC and the impact on oxidative stress. Methodology/Findings Fluorescently labeled lipid and protein moieties of oxLDL co-localized within endosomal and lysosomal compartments in U937 human monocytic cells. In contrast, the lipid moiety of oxLDL-IC was detected in the endosomal compartment, whereas its apolipoprotein moiety advanced to the lysosomal compartment. Cells treated with oxLDL-IC prior to oxLDL demonstrated co-localization of internalized lipid moieties from both oxLDL and oxLDL-IC in the endosomal compartment. This sequential treatment likely inhibited oxLDL lipid moieties from trafficking to the lysosomal compartment. In RAW 264.7 macrophages, oxLDL-IC but not oxLDL induced GFP-tagged heat shock protein 70 (HSP70) and HSP70B', which co-localized with the lipid moiety of oxLDL-IC in the endosomal compartment. This suggests that HSP70 family members might prevent the degradation of the internalized lipid moiety of oxLDL-IC by delaying its advancement to the lysosome. The data also showed that mitochondrial membrane potential was decreased and generation of reactive oxygen and nitrogen species was increased in U937 cell treated with oxLDL compared to oxLDL-IC. Conclusions/Significance Findings suggest that lipid and apolipoprotein moieties of oxLDL-IC traffic to separate cellular compartments, and that HSP70/70B' might sequester the lipid moiety of oxLDL-IC in the

  13. LRP6 Protein Regulates Low Density Lipoprotein (LDL) Receptor-mediated LDL Uptake*

    PubMed Central

    Ye, Zhi-jia; Go, Gwang-Woong; Singh, Rajvir; Liu, Wenzhong; Keramati, Ali Reza; Mani, Arya

    2012-01-01

    Genetic variations in LRP6 gene are associated with high serum LDL cholesterol levels. We have previously shown that LDL clearance in peripheral B-lymphocytes of the LRP6R611C mutation carriers is significantly impaired. In this study we have examined the role of wild type LRP6 (LRP6WT) and LRP6R611C in LDL receptor (LDLR)-mediated LDL uptake. LDL binding and uptake were increased when LRP6WT was overexpressed and modestly reduced when it was knocked down in LDLR-deficient CHO (ldlA7) cells. These findings implicated LRP6 in LDLR-independent cellular LDL binding and uptake. However, LRP6 knockdown in wild type CHO cells resulted in a much greater decline in LDL binding and uptake compared with CHO-ldlA7 cells, suggesting impaired function of the LDLR. LDLR internalization was severely diminished when LRP6 was knocked down and was restored after LRP6 was reintroduced. Further analysis revealed that LRP6WT forms a complex with LDLR, clathrin, and ARH and undergoes a clathrin-mediated internalization after stimulation with LDL. LDLR and LRP6 internalizations as well as LDL uptake were all impaired in CHO-k1 cells expressing LRP6R611C. These studies identify LRP6 as a critical modulator of receptor-mediated LDL endocytosis and introduce a mechanism by which variation in LRP6 may contribute to high serum LDL levels. PMID:22128165

  14. LDL cholesterol: controversies and future therapeutic directions.

    PubMed

    Ridker, Paul M

    2014-08-16

    Lifelong exposure to raised concentrations of LDL cholesterol increases cardiovascular event rates, and the use of statin therapy as an adjunct to diet, exercise, and smoking cessation has proven highly effective in reducing the population burden associated with hyperlipidaemia. Yet, despite consistent biological, genetic, and epidemiological data, and evidence from randomised trials, there is controversy among national guidelines and clinical practice with regard to LDL cholesterol, its measurement, the usefulness of population-based screening, the net benefit-to-risk ratio for different LDL-lowering drugs, the benefit of treatment targets, and whether aggressive lowering of LDL is safe. Several novel therapies have been introduced for the treatment of people with genetic defects that result in loss of function within the LDL receptor, a major determinant of inherited hyperlipidaemias. Moreover, the usefulness of monoclonal antibodies that extend the LDL-receptor lifecycle (and thus result in substantial lowering of LDL cholesterol below the levels achieved with statins alone) is being assessed in phase 3 trials that will enrol more than 60,000 at-risk patients worldwide. These trials represent an exceptionally rapid translation of genetic observations into clinical practice and will address core questions of how low LDL cholesterol can be safely reduced, whether the mechanism of LDL-cholesterol lowering matters, and whether ever more aggressive lipid-lowering provides a safe, long-term mechanism to prevent atherothrombotic complications. PMID:25131980

  15. The late addition of core lipids to nascent apolipoprotein B100, resulting in the assembly and secretion of triglyceride-rich lipoproteins, is independent of both microsomal triglyceride transfer protein activity and new triglyceride synthesis.

    PubMed

    Pan, Meihui; Liang Js, Jun-shan; Fisher, Edward A; Ginsberg, Henry N

    2002-02-01

    Although microsomal triglyceride transfer protein (MTP) and newly synthesized triglyceride (TG) are critical for co-translational targeting of apolipoprotein B (apoB100) to lipoprotein assembly in hepatoma cell lines, their roles in the later stages of lipoprotein assembly remain unclear. Using N-acetyl-Leu-Leu-norleucinal to prevent proteasomal degradation, HepG2 cells were radiolabeled and chased for 0-90 min (chase I). The medium was changed and cells chased for another 150 min (chase II) in the absence (control) or presence of Pfizer MTP inhibitor CP-10447 (CP). As chase I was extended, inhibition of apoB100 secretion by CP during chase II decreased from 75.9% to only 15% of control (no CP during chase II). Additional studies were conducted in which chase I was either 0 or 90 min, and chase II was in the presence of [(3)H]glycerol and either BSA (control), CP (inhibits both MTP activity and TG synthesis),BMS-1976360-1) (BMS) (inhibits only MTP activity), or triacsin C (TC) (inhibits only TG synthesis). When chase I was 0 min, CP, BMS, and TC reduced apoB100 secretion during chase II by 75.3, 73.9, and 53.9%. However, when chase I was 90 min, those agents reduced apoB100 secretion during chase II by only 16.0, 19.2, and 13.9%. Of note, all three inhibited secretion of newly synthesized TG during chase II by 80, 80, and 40%, whether chase I was 0 or 90 min. In both HepG2 cells and McA-RH7777 cells, if chase I was at least 60 min, inhibition of TG synthesis and/or MTP activity did not affect the density of secreted apoB100-lipoproteins under basal conditions. Oleic acid increased secretion of TG-enriched apoB100-lipoproteins similarly in the absence or presence of either of CP, BMS, or TC. We conclude that neither MTP nor newly synthesized TG is necessary for the later stages of apoB100-lipoprotein assembly and secretion in either HepG2 or McA-RH7777 cells. PMID:11704664

  16. [Comparison of calculated LDL cholesterol (LDL-C) versus measured LDL cholesterol (LDL-M) and potential impact in terms of therapeutic management].

    PubMed

    Reignier, Arnaud; Sacchetto, Emilie; Hardouin, Jean-Benoît; Orsonneau, Jean-Luc; Le Carrer, Didier; Delaroche, Odile; Bigot-Corbel, Edith

    2014-01-01

    LDL-cholesterol value is one of the criteria used by the Haute autorité de santé (HAS) in the management of patients in primary and secondary prevention with the aim to reduce cardiovascular mortality. In this respect, the recommendations have been established based on target to achieve LDL-cholesterol. Currently in France, the determination of LDL-cholesterol is mainly carried out by the Friedewald formula whose limits are well known. However, reliable methods for the determination of LDL-cholesterol exist. We compared the results of calculated and measured LDL-cholesterol obtained from 444 patients presenting normal triglyceridemia values in terms of ranking relative to the thresholds of the HAS. The correlation between the two methods is quite good, but a significant difference (p <0.0001) was observed between the calculated and measured values of LDL-cholesterol. On the other hand in 17% of cases the classification of subjects will be different, with a majority so overestimation of calculated LDL-cholesterol with respect to measured LDL-cholesterol. This overestimation is not proportional, in fact most values measured LDL-cholesterol, the higher the calculate-measured difference is important. The rating difference is particularly important when subjects have between 1 and 3 factors of cardiovascular risk where the target LDL-cholesterol to achieve is between 1.3 and 1.9 g/L. The management of patients with lipid lowering may potentially be dependent on the method used for the determination of LDL-cholesterol. PMID:25336132

  17. A Complete Backbone Assignment of the Apolipoprotein E LDL Receptor Binding Domain [Letter to the Editor

    SciTech Connect

    Xu, Chao; Sivashanmugam, Arun; Hoyt, David W.; Wang, Jianjun

    2005-06-01

    Human apolipoprotein E (apoE) is a 299-residue exchangeable apolipoprotein that was initially recognized as a major determinant in lipoprotein metabolism and cardiovascular diseases. Recent evidence has indicated that apoE also plays critical roles in several other important biological processes not directly related to its lipid transport function, including Alzheimer's disease, cognitive function, immunoregulation, cell signaling, and possibly even infectious diseases. ApoE contains two structural/functional domains: A N-terminal domain spanning residues 1-191 that is responsible for apoE's LDL receptor binding activity and a C-terminal domain (residues 216-199) that is responsible for lipoprotein-binding (1). The x-ray crystal structure of the lipid-free apoE N-terminal domain was solved by Wilson et al in 1991 which represented the only high-resolution structure of this protein. This structure showed an unusually elongated four-helix bundle (2) that was organized in such 2 a way that its hydrophobic faces were directed towards the protein interior, whereas the hydrophilic faces were oriented towards the solvent. The major receptor-binding region, residues 130-150, was located on the fourth helix. The amphipathic a-helices were connected by short loops, giving rise to a compact, globular structure. However, this structure only contained residues 23-165. Recent studies have shown that residues beyond residues 23-165 are also very important to the apoE LDL receptor binding activity. For example, a mutation at position R172 reduces the receptor binding activity of apoE to only {approx}2% (3). In addition, an E3K mutant significantly increased the apoE receptor binding activity as well (4). While the x-ray crystal structure of the apoE N-terminal domain provided detailed structural information for most region of this domain, this structure does not provide an explanation of the above experimental results regarding the structural contribution to apoE's LDL receptor

  18. Competitive inhibition of LDL binding and uptake by HDL in aortic endothelial cells

    SciTech Connect

    Alexander, J.J.; Miguel, R.; Graham, D. )

    1990-09-01

    High-density lipoprotein (HDL) may inhibit the binding and cellular uptake of low-density lipoprotein (LDL) as one means of regulating the delivery of exogenous cholesterol to nonhepatic tissues. This may play an important role in atherogenesis, by altering lipid metabolism in cells of the arterial wall. To verify and better characterize this effect, endothelial cells were harvested from bovine aorta and maintained in tissue culture. Following initial preincubation in lipid-deficient culture media, these cells were incubated for 2 hr at 4 degrees C in media containing 125I-LDL (10 micrograms protein/ml) and varying concentrations of either HDL (0-400 micrograms protein/ml) or comparable amounts of Apoprotein A (Apo A), the major protein component of HDL. Intracellular and trypsin-released counts were assayed separately, as a measurement of cellular uptake and membrane bound LDL, respectively. Results of this study indicated an inhibition of LDL binding and uptake by HDL (P less than 0.005, ANOVA). A similar inhibition was found with Apo A alone (P less than 0.005). When identical studies were performed using 125I-Apoprotein B, the protein component of LDL, and Apo A, the latter was found to inhibit the binding of Apo B to the same extent (P less than 0.0006). These results indicate that HDL does inhibit LDL binding and uptake by bovine aortic endothelial cells and that, because this effect is seen equally with only the protein component of these lipoprotein particles, it is most likely due to competitive binding at the receptor level rather than to stearic hindrance or an alteration of the cell membrane.

  19. LDL-Apheresis: Technical and Clinical Aspects

    PubMed Central

    Bambauer, Rolf; Bambauer, Carolin; Lehmann, Boris; Latza, Reinhard; Schiel, Ralf

    2012-01-01

    The prognosis of patients suffering from severe hyperlipidemia, sometimes combined with elevated lipoprotein (a) levels, and coronary heart disease refractory to diet and lipid-lowering drugs is poor. For such patients, regular treatment with low-density lipoprotein (LDL) apheresis is the therapeutic option. Today, there are five different LDL-apheresis systems available: cascade filtration or lipid filtration, immunoadsorption, heparin-induced LDL precipitation, dextran sulfate LDL adsorption, and the LDL hemoperfusion. There is a strong correlation between hyperlipidemia and atherosclerosis. Besides the elimination of other risk factors, in severe hyperlipidemia therapeutic strategies should focus on a drastic reduction of serum lipoproteins. Despite maximum conventional therapy with a combination of different kinds of lipid-lowering drugs, sometimes the goal of therapy cannot be reached. Hence, in such patients, treatment with LDL-apheresis is indicated. Technical and clinical aspects of these five different LDL-apheresis methods are shown here. There were no significant differences with respect to or concerning all cholesterols, or triglycerides observed. With respect to elevated lipoprotein (a) levels, however, the immunoadsorption method seems to be most effective. The different published data clearly demonstrate that treatment with LDL-apheresis in patients suffering from severe hyperlipidemia refractory to maximum conservative therapy is effective and safe in long-term application. PMID:22654591

  20. Combined effects of cholesterol reduction and apolipoprotein A-I expression on atherosclerosis in LDL receptor deficient mice.

    PubMed

    Kawashiri, Masa-aki; Zhang, YuZhen; Puré, Ellen; Rader, Daniel J

    2002-11-01

    Reduction of total and LDL cholesterol reduces atherosclerosis and clinical cardiovascular events. High density lipoprotein (HDL) cholesterol levels have a strong inverse association with atherosclerosis, and overexpression of apolipoprotein A-I (apoA-I), the major protein component of HDL, reduces atherosclerosis in hypercholesterolemic animals. However, little is known about the potential for additive or synergistic effects between cholesterol reduction and apoA-I overexpression on atherosclerosis. In the current study, we tested the hypothesis that significant reduction of plasma cholesterol combined with overexpression of apoA-I would reduce atherosclerosis to a greater extent than either one alone. We used somatic gene transfer of the LDL receptor (to induce cholesterol reduction) and apoA-I in LDL receptor deficient mice fed a Western type diet and compared the combination to expression of each gene alone and to controls. Atherosclerosis was quantitated using two independent methods, by en face analysis of the entire aorta and by cross-sectional analysis of the aortic root. Although the reduction of cholesterol was transient, expression of the LDL receptor alone significantly reduced atherosclerosis by 45% in the aorta and 44% in the aortic root compared with controls. Overexpression of human apoA-I alone reduced atherosclerosis by 42% in the aorta and 44% in the aortic root compared with controls. Co-expression of the LDL receptor with apoA-I resulted in significantly higher levels of apoA-I than expression of apoA-I alone. Although co-expression of the LDL receptor and apoA-I reduced atherosclerosis by 37% in the aorta and 32% in the aortic root compared with controls, the reduction in atherosclerosis was no different than that seen with expression of the LDL receptor alone or apoA-I alone. In summary, in this relatively short-term murine model, simultaneous reduction of cholesterol and expression of apoA-I was associated with higher levels of apoA-I than

  1. Comparative reactivity of the myeloperoxidase-derived oxidants HOCl and HOSCN with low-density lipoprotein (LDL): Implications for foam cell formation in atherosclerosis.

    PubMed

    Ismael, Fahd O; Proudfoot, Julie M; Brown, Bronwyn E; van Reyk, David M; Croft, Kevin D; Davies, Michael J; Hawkins, Clare L

    2015-05-01

    Atherosclerosis is characterised by the accumulation of lipids within macrophages in the artery wall. Low-density lipoprotein (LDL) is the source of this lipid, owing to the uptake of oxidised LDL by scavenger receptors. Myeloperoxidase (MPO) released by leukocytes during inflammation produces oxidants that are implicated in atherosclerosis. Modification of LDL by the MPO oxidant hypochlorous acid (HOCl), results in extensive lipid accumulation by macrophages. However, the reactivity of the other major MPO oxidant, hypothiocyanous acid (HOSCN) with LDL is poorly characterised, which is significant given that thiocyanate is the favoured substrate for MPO. In this study, we comprehensively compare the reactivity of HOCl and HOSCN with LDL, and show key differences in the profile of oxidative damage observed. HOSCN selectively modifies Cys residues on apolipoprotein B100, and oxidises cholesteryl esters resulting in formation of lipid hydroperoxides, 9-hydroxy-10,12-octadecadienoic acid (9-HODE) and F2-isoprostanes. The modification of LDL by HOSCN results macrophage lipid accumulation, though generally to a lesser extent than HOCl-modified LDL. This suggests that a change in the ratio of HOSCN:HOCl formation by MPO from variations in plasma thiocyanate levels, will influence the nature of LDL oxidation in vivo, and has implications for the progression of atherosclerosis. PMID:25795019

  2. In vivo gene therapy for hyperlipidemia: phenotypic correction in Watanabe rabbits by hepatic delivery of the rabbit LDL receptor gene.

    PubMed Central

    Li, J; Fang, B; Eisensmith, R C; Li, X H; Nasonkin, I; Lin-Lee, Y C; Mims, M P; Hughes, A; Montgomery, C D; Roberts, J D

    1995-01-01

    Elevations of plasma total or LDL cholesterol are major risk factors for cardiovascular disease. Efforts directed at preventing and treating cardiovascular disease have often focused on reducing the levels of these substances in the blood. The Watanabe Heritable Hyperlipidemic Rabbit, which has exceedingly high plasma cholesterol levels resulting from an LDL receptor deficiency, provides an excellent animal model for testing new treatments. A recombinant adenoviral vector containing the rabbit LDL receptor cDNA was administered to Watanabe rabbits. Plasma total cholesterol levels in the treated animals were reduced from 825.5 +/- 69.8 (mean +/- SD) to 247.3 +/- 61.5 mg/dl 6 d after infusion. These animals also demonstrated a 300-400% increase in plasma levels of HDL cholesterol and apo AI 10 d after treatment. As a result, the LDL:HDL ratio exhibited a dramatic decrease. Because only the rabbit LDL receptor gene was used for treatment, the results strongly suggest that the elevations of plasma HDL cholesterol and apo AI were secondary to a reduction in plasma total cholesterol in the treated animals. These results suggest an inverse relationship between plasma LDL and HDL cholesterol levels and imply that reduction of LDL cholesterol levels may have a beneficial effect on plasma HDL cholesterol. PMID:7860759

  3. In vivo gene therapy for hyperlipidemia: phenotypic correction in Watanabe rabbits by hepatic delivery of the rabbit LDL receptor gene.

    PubMed

    Li, J; Fang, B; Eisensmith, R C; Li, X H; Nasonkin, I; Lin-Lee, Y C; Mims, M P; Hughes, A; Montgomery, C D; Roberts, J D

    1995-02-01

    Elevations of plasma total or LDL cholesterol are major risk factors for cardiovascular disease. Efforts directed at preventing and treating cardiovascular disease have often focused on reducing the levels of these substances in the blood. The Watanabe Heritable Hyperlipidemic Rabbit, which has exceedingly high plasma cholesterol levels resulting from an LDL receptor deficiency, provides an excellent animal model for testing new treatments. A recombinant adenoviral vector containing the rabbit LDL receptor cDNA was administered to Watanabe rabbits. Plasma total cholesterol levels in the treated animals were reduced from 825.5 +/- 69.8 (mean +/- SD) to 247.3 +/- 61.5 mg/dl 6 d after infusion. These animals also demonstrated a 300-400% increase in plasma levels of HDL cholesterol and apo AI 10 d after treatment. As a result, the LDL:HDL ratio exhibited a dramatic decrease. Because only the rabbit LDL receptor gene was used for treatment, the results strongly suggest that the elevations of plasma HDL cholesterol and apo AI were secondary to a reduction in plasma total cholesterol in the treated animals. These results suggest an inverse relationship between plasma LDL and HDL cholesterol levels and imply that reduction of LDL cholesterol levels may have a beneficial effect on plasma HDL cholesterol. PMID:7860759

  4. Empagliflozin, via Switching Metabolism Toward Lipid Utilization, Moderately Increases LDL Cholesterol Levels Through Reduced LDL Catabolism.

    PubMed

    Briand, François; Mayoux, Eric; Brousseau, Emmanuel; Burr, Noémie; Urbain, Isabelle; Costard, Clément; Mark, Michael; Sulpice, Thierry

    2016-07-01

    In clinical trials, a small increase in LDL cholesterol has been reported with sodium-glucose cotransporter 2 (SGLT2) inhibitors. The mechanisms by which the SGLT2 inhibitor empagliflozin increases LDL cholesterol levels were investigated in hamsters with diet-induced dyslipidemia. Compared with vehicle, empagliflozin 30 mg/kg/day for 2 weeks significantly reduced fasting blood glucose by 18%, with significant increase in fasting plasma LDL cholesterol, free fatty acids, and total ketone bodies by 25, 49, and 116%, respectively. In fasting conditions, glycogen hepatic levels were further reduced by 84% with empagliflozin, while 3-hydroxy-3-methylglutaryl-CoA reductase activity and total cholesterol hepatic levels were 31 and 10% higher, respectively (both P < 0.05 vs. vehicle). A significant 20% reduction in hepatic LDL receptor protein expression was also observed with empagliflozin. Importantly, none of these parameters were changed by empagliflozin in fed conditions. Empagliflozin significantly reduced the catabolism of (3)H-cholesteryl oleate-labeled LDL injected intravenously by 20%, indicating that empagliflozin raises LDL levels through reduced catabolism. Unexpectedly, empagliflozin also reduced intestinal cholesterol absorption in vivo, which led to a significant increase in LDL- and macrophage-derived cholesterol fecal excretion (both P < 0.05 vs. vehicle). These data suggest that empagliflozin, by switching energy metabolism from carbohydrate to lipid utilization, moderately increases ketone production and LDL cholesterol levels. Interestingly, empagliflozin also reduces intestinal cholesterol absorption, which in turn promotes LDL- and macrophage-derived cholesterol fecal excretion. PMID:27207551

  5. Technetium-99m labelled LDL as a tracer for quantitative LDL scintigraphy. II. In vivo validation, LDL receptor-dependent and unspecific hepatic uptake and scintigraphic results.

    PubMed

    Leitha, T; Staudenherz, A; Gmeiner, B; Hermann, M; Hüttinger, M; Dudczak, R

    1993-08-01

    The purpose of this study was to determine whether the hepatic uptake of dialysed technetium-99m labelled low-density lipoprotein (99mTc-LDL) reflects the hepatic LDL receptor activity and to what extent the non-LDL receptor-dependent 99mTc-LDL uptake by non-parenchymal cells relates to the diagnostic utility of quantitative 99mTc-LDL scintigraphy of the liver. New Zealand White rabbits and Watanabe Heritable Hyperlipidaemic rabbits, which were sacrificed 24 h after simultaneous injection of 99mTc-LDL and iodine-125 labelled LDL, were clearly discriminated by their hepatic 99mTc-LDL uptake according to their genetically different hepatic LDL receptor activity. Yet the hepatic 99mTc-LDL uptake exceeded the 125I-LDL uptake in all animals. The different hepatic uptake of the tracers was elucidated in the isolated perfused rat liver and was due to rapid intracellular degradation and the release of low molecular catabolites of 125I-LDL. In contrast, 99mTc activity was trapped in the liver. Analysis of biliary 99mTc activity provided evidence for the excretion of 99mTc-labelled apolipoprotein B. The amount of biliary excreted protein-bound 99mTc was linked to total hepatic 99mTc-LDL uptake and presumably reflected LDL receptor-mediated apolipoprotein excretion. Collagenase liver perfusion in Sprague-Dawley rats 90 min following simultaneous injection of 99mTc- and 125I-LDL and subsequent cell separation by gradient centrifugation revealed that 99mTc-LDL and 125I-LDL had a comparably low uptake into non-parenchymal cells; thus its contribution can be neglected for scintigraphic purposes. Planar scintigraphy was performed in New Zealand White and Watanabe Heritable Hyperlipidaemic rabbits.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8404953

  6. Anti-atherosclerotic potential of gossypetin via inhibiting LDL oxidation and foam cell formation

    SciTech Connect

    Chen, Jing-Hsien; Tsai, Chia-Wen; Wang, Chi-Ping; Lin, Hui-Hsuan

    2013-10-15

    Gossypetin, a flavone originally isolated from Hibiscus species, has been shown to possess antioxidant, antimicrobial, and antimutagenic activities. Here, we investigated the mechanism(s) underlying the anti-atherosclerotic potential of gossypetin. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) scavenging activity assay showed that the addition of > 50 μM of gossypetin could scavenge over 50% of DPPH radicals. The inhibitory effects of gossypetin on the lipid and protein oxidation of LDL were defined by thiobarbituric acid reactive substance (TBARS) assay, the relative electrophoretic mobility (REM) of oxidized LDL (ox-LDL), and fragmentation of apoB in the Cu{sup 2+}-induced oxidation of LDL. Gossypetin showed potential in reducing ox-LDL-induced foam cell formation and intracellular lipid accumulation, and uptake ability of macrophages under non-cytotoxic concentrations. Molecular data showed that these influences of gossypetin might be mediated via peroxisome proliferator-activated receptor α (PPARα)/liver-X receptor α (LXRα)/ATP-binding cassette transporter A1 (ABCA1) and PPARγ/scavenger receptor CD36 pathways, as demonstrated by the transfection of PPARα siRNA or PPARγ expression vector. Our data implied that gossypetin regulated the PPAR signals, which in turn led to stimulation of cholesterol removal from macrophages and delay atherosclerosis. These results suggested that gossypetin potentially could be developed as an anti-atherosclerotic agent. - Highlights: • The anti-atherosclerotic effect of gossypetin in vitro was examined. • Gossypetin inhibited LDL oxidation. • Gossypetin showed potential in reducing on the formation of foam cells. • Gossypetin functions against ox-LDL through PPARa activation and PPARγ depression.

  7. Pectin isolated from prickly pear (Opuntia SSP) modifies LDL metabolism in cholesterol-fed guinea pigs

    SciTech Connect

    Fernandez, M.L.; McNamara, D.J. )

    1990-02-26

    The effects of dietary pectin on plasma and hepatic cholesterol (CH) levels, plasma lipoprotein profiles, hepatic 3-hydroxy-3-methylglutaryl Coenzyme A (HMG-CoA) reductase activity, and low density lipoprotein (LDL) binding to hepatic membranes were investigated by feeding 1% pectin to guinea pigs on a high CH diet. Animals were fed either chow + 0.25% CH (HC diet) or the CH diet + 1% prickly pear pectin (HC-P diet) for 25 days. Plasma CH levels were decreased 26% by the HC-P with 33% decreases in LDL and KDL. LDL peak density shifted from 1.040 to 1.055 g/ml with pectin. Hepatic total, free and esterified CH levels were reduced 60, 40 and 85% respectively by the HC-P diet. In contrast, HMG-CoA reductase activity was unaffected. {sup 125}I-LDL binding to hepatic membranes was increased by intake of the HC-P diet compared to the HC diet. The affinity of the apo B/E receptor for LDL was not affected by dietary pectin while the receptor number was increased 1.5-fold in animals on the HC-P diet. These data suggest that the parameters of HC metabolism affected by dietary pectin are consistent with an increased demand on the hepatic CH pools which possibly results from increased fecal excretion of bile acids.

  8. [Metabolic syndrome and small dense LDL].

    PubMed

    Yoshino, Gen

    2006-12-01

    Due to the recent westernization of our lifestyle, it is speculated that the prevalence of metabolic syndrome in the young generation will increase in Japan. Different from Western populations, because of our lifestyle as "farmers" from ancient times, excess energy has been stored outside of the body, and the accumulation of visceral fat might have serious adverse effects on glucose and lipid metabolism. Therefore, we must carefully diagnose and treat patients with metabolic syndrome, which is diagnosed based on the existence of visceral obesity. On the other hand, much attention has been paid recently to the atherogenicity of small dense LDL. In this chapter I will introduce a newly established method for estimating the plasma concentration of small dense LDL-cholesterol. Furthermore, the relationship between subclinical atherosclerosis and small dense LDL in metabolic syndrome will be discussed. PMID:17265899

  9. Development of NUPAC 140B 100 ton rail/barge cask

    SciTech Connect

    Not Available

    1990-04-01

    The NuPac 140-B 100 Ton Rail/Barge Shipping Cask Preliminary Design Report (PDR) presents a general introduction to, and description of, the NuPac 140-B Cask and its fuel payload. The NuPac 140-B Cask, Model: NuPac 140-B, is being designed by Nuclear Packaging, Inc., to meet or exceed all NRC and Department of Transportation regulations governing the shipment of radioactive material. Specifically the Cask is being developed as a safe means of transporting spent light-water-reactor (LWR) fuels from existing and proposed reactor facilities to a repository and/or a monitored retrievable storage (MRS) facility. The primary transportation mode is by railroad, although the shipping package is designed to be transported by barge and by truck shipment on a special overweight basis for short distances. This feature allows the servicing of reactor sites and other facilities which lack direct railroad access.

  10. The effects of genotype and infant weight on adult plasma levels of fibrinogen, factor VII, and LDL cholesterol are additive.

    PubMed Central

    Henry, J A; Bolla, M; Osmond, C; Fall, C; Barker, D J; Humphries, S E

    1997-01-01

    High circulating levels of cholesterol, particularly low density lipoprotein (LDL) cholesterol and the clotting factors fibrinogen and factor VII, are associated with increased risk of myocardial infarction. Variations in the plasma levels of these factors are determined in part by polymorphisms in the genes concerned and also by weight at 1 year (infant weight). We have looked at the possibility of interactions between these genetic factors and infant weight in a sample of 290 men and 192 women from Hertfordshire using the beta-fibrinogen G/A-455, factor VII R353Q, and ApoE polymorphisms. The rare allele frequencies of the three polymorphisms were 0.19 for beta-fibrinogen, 0.10 for factor VII, and 0.07 and 0.13 for the 2 and 4 alleles of ApoE, and these frequencies were not different in subjects of different infant weight. In this sample, the polymorphisms showed the expected effects on plasma levels of fibrinogen, factor VII, and LDL cholesterol. The A-455 allele was associated with higher fibrinogen levels but the effect was only statistically significant in women (p = 0.003). The R353 allele was associated with higher factor VII activity in both men and women (p < 0.0001 for both). The ApoE2 allele was associated with lower levels of LDL cholesterol (p = 0.03 in men, p = 0.006 in women), while the ApoE4 allele was associated with higher levels (p < 0.001 in men, not significant in women). In this sample of men and women the effect of low infant weight was only associated with significant effects on fibrinogen and LDL cholesterol in the group of men (p = 0.005 and p = 0.008 respectively). Compared with the E3E3 subjects, the LDL lowering effect of the E2 allele and the raising effect of the E4 allele was greater in those with low infant weight compared with those with high infant weight (low v high infant weight for E2: 12.7% v 9.4%; for E4 12.7% v 8.5%). Although in this sample the interactive effect did not reach statistical significance, the additive effect

  11. Effects of extended-release niacin/laropiprant, simvastatin, and the combination on correlations between apolipoprotein B, LDL cholesterol, and non-HDL cholesterol in patients with dyslipidemia

    PubMed Central

    Farnier, Michel; Chen, Erluo; Johnson-Levonas, Amy O; McCrary Sisk, Christine; Mitchel, Yale B

    2014-01-01

    Background Statins modify correlations between apolipoprotein B (apoB) and low-density lipoprotein cholesterol (LDL-C) and apoB and non-high-density lipoprotein cholesterol (non-HDL-C); however, it is not known whether niacin-based therapies have similar effects. Objective To evaluate the effects of extended-release niacin (ERN)/laropiprant (LRPT), simvastatin (SIMVA), and ERN/LRPT + SIMVA (pooled ERN/LRPT + SIMVA) on apoB:LDL-C and apoB:non-HDL-C correlations in dyslipidemic patients. Methods This post-hoc analysis of a 12-week study evaluated the apoB:LDL-C and apoB:non-HDL-C correlations in dyslipidemic patients randomized equally to double-blind ERN/LRPT 1 g/20 mg, SIMVA 10, 20, or 40 mg, or ERN/LRPT 1 g/20 mg + SIMVA (10, 20, or 40 mg) once daily for 4 weeks. At week 5, doses were doubled in all groups except SIMVA 40 mg (unchanged) and ERN/LRPT 1 g/20 mg + SIMVA 40 mg (switched to ERN/LRPT 2 g/40 mg + SIMVA 40 mg). Simple linear regression analyses were used to calculate LDL-C and non-HDL-C levels corresponding to known apoB baseline values (ie, in untreated patients) and following treatment. Results The apoB:LDL-C and apoB:non-HDL-C correlations were higher and the predicted LDL-C and non-HDL-C levels for a known apoB value were considerably lower following treatment with ERN/LRPT, SIMVA and ERN/LRPT + SIMVA compared with untreated patients at baseline. Conclusion Greater dissociation of apoB, LDL-C, and non-HDL-C targets occur following treatment with ERN/LRPT, SIMVA, and ERN/LRPT + SIMVA in patients with dyslipidemia. The achievement of more aggressive LDL-C and non-HDL-C goals in patients receiving lipid-modifying therapy may further reduce coronary risk by normalizing apoB-containing atherogenic lipoproteins. PMID:24855368

  12. LOX-1, OxLDL, and Atherosclerosis

    PubMed Central

    Catapano, Alberico Luigi

    2013-01-01

    Oxidized low-density lipoprotein (OxLDL) contributes to the atherosclerotic plaque formation and progression by several mechanisms, including the induction of endothelial cell activation and dysfunction, macrophage foam cell formation, and smooth muscle cell migration and proliferation. Vascular wall cells express on their surface several scavenger receptors that mediate the cellular effects of OxLDL. The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the main OxLDL receptor of endothelial cells, and it is expressed also in macrophages and smooth muscle cells. LOX-1 is almost undetectable under physiological conditions, but it is upregulated following the exposure to several proinflammatory and proatherogenic stimuli and can be detected in animal and human atherosclerotic lesions. The key contribution of LOX-1 to the atherogenic process has been confirmed in animal models; LOX-1 knockout mice exhibit reduced intima thickness and inflammation and increased expression of protective factors; on the contrary, LOX-1 overexpressing mice present an accelerated atherosclerotic lesion formation which is associated with increased inflammation. In humans, LOX-1 gene polymorphisms were associated with increased susceptibility to myocardial infarction. Inhibition of the LOX-1 receptor with chemicals or antisense nucleotides is currently being investigated and represents an emerging approach for controlling OxLDL-LOX-1 mediated proatherogenic effects. PMID:23935243

  13. Triggering of inflammatory response by myeloperoxidase-oxidized LDL.

    PubMed

    Boudjeltia, Karim Zouaoui; Legssyer, Ilham; Van Antwerpen, Pierre; Kisoka, Roger Lema; Babar, Sajida; Moguilevsky, Nicole; Delree, Paul; Ducobu, Jean; Remacle, Claude; Vanhaeverbeek, Michel; Brohee, Dany

    2006-10-01

    The oxidation theory proposes that LDL oxidation is an early event in atherosclerosis and that oxidized LDL contributes to atherogenesis in triggering inflammation. In contrast to the copper-modified LDL, there are few studies using myeloperoxidase-modified LDL (Mox-LDL) as an inflammation inducer. Our aim is to test whether Mox-LDL could constitute a specific inducer of the inflammatory response. Albumin, which is the most abundant protein in plasma and which is present to an identical concentration of LDL in the intima, was used for comparison. The secretion of IL-8 by endothelial cells (Ea.hy926) and TNF-alpha by monocytes (THP-1) was measured in the cell medium after exposure of these cells to native LDL, native albumin, Mox-LDL, or Mox-albumin. We observed that Mox-LDL induced a 1.5- and 2-fold increase (ANOVA; P < 0.001) in IL-8 production at 100 microg/mL and 200 microg/mL, respectively. The incubation of THP-1 cells with Mox-LDL (100 microg/mL) increased the production of TNF-alpha 2-fold over the control. Native LDL, albumin, and Mox-albumin showed no effect in either cellular types. The myeloperoxidase-modified LDL increase in cytokine release by endothelial and monocyte cells and by firing both local and systemic inflammation could induce atherogenesis and its development. PMID:17167545

  14. Low Levels of IgM Antibodies against an Advanced Glycation Endproduct-Modified Apolipoprotein B100 Peptide Predict Cardiovascular Events in Nondiabetic Subjects.

    PubMed

    Engelbertsen, Daniel; Vallejo, Jenifer; Quách, Tâm Dan; Fredrikson, Gunilla Nordin; Alm, Ragnar; Hedblad, Bo; Björkbacka, Harry; Rothstein, Thomas L; Nilsson, Jan; Bengtsson, Eva

    2015-10-01

    Increased glucose levels are associated with the generation of advanced glycation endproduct (AGE) modifications. Interaction between AGE-modified plaque components and immune cells is believed to have an important role in the development of vascular complications in diabetes. Methylglyoxal (MGO) is one type of reactive aldehyde that gives rise to AGE modification. The present study analyzed whether autoantibodies against MGO-modified epitopes of the low-density lipoprotein apolipoprotein B (apoB) 100 predict cardiovascular events. A library consisting of 302 peptides comprising the complete apoB100 molecule was screened to identify peptides targeted by MGO-specific autoantibodies. Peptide (p) 220 (apoB amino acids 3286-3305) was identified as a major target. Baseline IgM and IgG against MGO-peptide 220 (p220) were measured in 700 individuals from the Malmö Diet and Cancer Cohort. A total of 139 cardiovascular events were registered during the 15-y follow-up period. Controlling for major cardiovascular risk factors demonstrated that subjects in the lowest tertile of MGO-p220 IgM had an increased risk for cardiovascular events (hazard ratio [95% confidence interval]: 2.07 [1.22-3.50]; p(trend) = 0.004). Interestingly, the association between MGO-p220 IgM and cardiovascular events remained and even tended to become stronger when subjects with prevalent diabetes were excluded from the analysis (2.51 [1.37-4.61]; p(trend) = 0.002). MGO-p220 IgM was inversely associated with blood glucose, but not with oxidized low-density lipoprotein. Finally, we demonstrate that anti-MGO-p220 IgM is produced by B1 cells. These data show that subjects with low levels of IgM recognizing MGO-modified p220 in apoB have an increased risk to develop cardiovascular events and that this association is present in nondiabetic subjects. PMID:26290603

  15. LDL oxidation as a biomarker of antioxidant status

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the past four decades, several hypotheses have evolved about the cause of atherosclerosis including vascular response to injury, vascular wall retention of low density lipoprotein (LDL), and oxidative modification of LDL. Because plasma contains robust antioxidant defenses and LDL contains li...

  16. Oxidized LDL: Diversity, Patterns of Recognition, and Pathophysiology

    PubMed Central

    Volkov, Suncica; Subbaiah, Papasani V.

    2010-01-01

    Abstract Oxidative modification of LDL is known to elicit an array of pro-atherogenic responses, but it is generally underappreciated that oxidized LDL (OxLDL) exists in multiple forms, characterized by different degrees of oxidation and different mixtures of bioactive components. The variable effects of OxLDL reported in the literature can be attributed in large part to the heterogeneous nature of the preparations employed. In this review, we first describe the various subclasses and molecular composition of OxLDL, including the variety of minimally modified LDL preparations. We then describe multiple receptors that recognize various species of OxLDL and discuss the mechanisms responsible for the recognition by specific receptors. Furthermore, we discuss the contentious issues such as the nature of OxLDL in vivo and the physiological oxidizing agents, whether oxidation of LDL is a prerequisite for atherogenesis, whether OxLDL is the major source of lipids in foam cells, whether in some cases it actually induces cholesterol depletion, and finally the Janus-like nature of OxLDL in having both pro- and anti-inflammatory effects. Lastly, we extend our review to discuss the role of LDL oxidation in diseases other than atherosclerosis, including diabetes mellitus, and several autoimmune diseases, such as lupus erythematosus, anti-phospholipid syndrome, and rheumatoid arthritis. Antioxid. Redox Signal. 13, 39–75. PMID:19888833

  17. The composition and metabolism of large and small LDL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Decreased size and increased density of LDL have been associated with increased coronary heart disease (CHD) risk. Elevated plasma concentrations of small dense LDL (sdLDL) correlate with high plasma triglycerides and low HDL cholesterol levels. This review highlights recent findings about the met...

  18. Tomato juice decreases LDL cholesterol levels and increases LDL resistance to oxidation.

    PubMed

    Silaste, Marja-Leena; Alfthan, Georg; Aro, Antti; Kesäniemi, Y Antero; Hörkkö, Sohvi

    2007-12-01

    High dietary intakes of tomato products are often associated with a reduced risk of CVD, but the atheroprotective mechanisms have not been established. This study was conducted to investigate the effects of increased dietary intake of tomato products on plasma lipids and LDL oxidation. The diet intervention included a baseline period, a 3-week low tomato diet (no tomato products allowed) and a 3-week high tomato diet (400 ml tomato juice and 30 mg tomato ketchup daily). Twenty-one healthy study subjects participated in the study. Total cholesterol concentration was reduced by 5.9 (sd 10) % (P = 0.002) and LDL cholesterol concentration by 12.9 (sd 17.0) % (P = 0.0002) with the high tomato diet compared to the low tomato diet. The changes in total and LDL cholesterol concentrations correlated significantly with the changes in serum lycopene (r 0.56, P = 0.009; r 0.60, P = 0.004, total and LDL, respectively), beta-carotene (r 0.58, P = 0.005; r 0.70, P < 0.001) and gamma-carotene concentrations (r 0.64, P = 0.002; r 0.64, P = 0.002). The level of circulating LDL to resist formation of oxidized phospholipids increased 13 % (P = 0.02) in response to the high tomato diet. In conclusion, a high dietary intake of tomato products had atheroprotective effects, it significantly reduced LDL cholesterol levels, and increased LDL resistance to oxidation in healthy normocholesterolaemic adults. These atheroprotective features associated with changes in serum lycopene, beta-carotene and gamma-carotene levels. PMID:17617941

  19. APOE polymorphisms influence longitudinal lipid trends preceding intracerebral hemorrhage

    PubMed Central

    Phuah, Chia-Ling; Raffeld, Miriam R.; Ayres, Alison M.; Gurol, M. Edip; Viswanathan, Anand; Greenberg, Steven M.; Biffi, Alessandro; Rosand, Jonathan

    2016-01-01

    Objective: We sought to determine whether APOE genotype influences a previously observed decline in serum total cholesterol (TC) and low-density lipoprotein (LDL) levels preceding primary intracerebral hemorrhage (ICH), as a potential demonstration of nonamyloid mechanisms of APOE in ICH risk. Methods: We performed a single-center retrospective longitudinal analysis using patients with known APOE genotype drawn from an ongoing cohort study of ICH. Serum lipid measurements for TC, triglycerides (TGs), LDL, and high-density lipoprotein (HDL) collected within 2 years before and after index ICH were extracted from electronic medical records. Piecewise linear mixed-effects models were used to compare APOE allele–specific effects on temporal serum lipid trends in ICH. Demographics, medical history, medications, and health maintenance data were included as fixed effects. Inter- and intraindividual variations in lipid levels were modeled as random effects. Results: A total of 124 ICH cases were analyzed. APOE ε4 carriers had greater rates of decline in serum TC and LDL within 6 months preceding ICH (TC: −7.30 mg/dL/mo, p = 0.0035; LDL: −8.44 mg/dL/mo, p = 0.0001). Conversely, serum TC and LDL levels in APOE ε2 carriers were unchanged within the same time period. APOE genotype had no associations with serum HDL or TG trends. Conclusions: APOE allele status predicts serum TC and LDL changes preceding acute ICH. Our results have implications for ongoing efforts in dissecting the role of dyslipidemia in cerebrovascular disease risk. APOE genotype–specific influence on lipid trends provides a clue for one mechanism by which APOE may influence risk of ICH. Further characterization of the metabolic roles of APOE is needed to improve the understanding of APOE biology in cerebrovascular disease risk. PMID:27433544

  20. New insights into the effects of the protein moiety of oxidized LDL (oxLDL).

    PubMed

    Vicca, Stéphanie; Massy, Ziad A; Hennequin, Carole; Rihane, Djamel; Nguyen-Khoa, Thao; Drüeke, Tilman B; Lacour, Bernard

    2003-05-01

    Oxidative stress has been implicated in the cardiovascular complications in chronic renal failure patients. Lipoprotein oxidation is involved in the genesis of atherosclerosis. Both the lipid and the protein moieties of low-density lipoproteins (LDL) are subject to oxidation. We have shown that oxidation of LDL by hypochlorous acid (HOCl) in vitro, reflecting increased myeloperoxidase (MPO) activity in vivo, leads mainly to modifications of apolipoproteins, such that the latter in turn induce high rates of apoptosis in a human monocytic cell line via a caspase-dependent pathway. These in vitro oxidative changes of LDL protein moiety, if shown to occur to a significant extent in uremic patients in vivo, may represent an important pathway in the pathogenesis of atherogenesis. PMID:12694326

  1. Is the Ratio of Antibodies Against Oxidized LDL to Oxidized LDL an Indicator of Cardiovascular Risk in Psoriasis?

    PubMed Central

    Rajappa, Medha; Mohan Thappa, Devinder; Chandrashekar, Laxmisha; Munisamy, Malathi; Revathy, G.

    2016-01-01

    Objectives Psoriasis is a chronic inflammatory skin disease. Chronic inflammation results in increased oxidative stress and oxidizes lipoproteins, increasing their atherogenicity. This study sought to estimate the levels of oxidized low-density lipoprotein (ox-LDL) and antibodies against oxidized LDL (anti-ox-LDL) and compute the ratio of anti-ox-LDL/ox-LDL as a single composite parameter to assess the oxidative lipoprotein burden as an indicator of cardiovascular risk in patients with psoriasis. Methods This cross-sectional study included 45 patients with psoriasis. All patients were given a psoriasis severity index score and their ox-LDL and anti-ox-LDL estimated using ELISA. Results The results of this study show an elevation in the ratio of anti-ox-LDL to ox-LDL in patients with psoriasis, which initiate and perpetuate the pathogenesis of psoriasis and its comorbidity, atherosclerotic cardiovascular disease. Conclusions Our results suggest that an elevated ratio of anti-ox-LDL/ox-LDL can serve as a composite parameter reflecting the total oxidative lipoprotein burden and cardiovascular risk in psoriasis patients. PMID:27602197

  2. Pharmacogenetic meta-analysis of genome-wide association studies of LDL cholesterol response to statins.

    PubMed

    Postmus, Iris; Trompet, Stella; Deshmukh, Harshal A; Barnes, Michael R; Li, Xiaohui; Warren, Helen R; Chasman, Daniel I; Zhou, Kaixin; Arsenault, Benoit J; Donnelly, Louise A; Wiggins, Kerri L; Avery, Christy L; Griffin, Paula; Feng, QiPing; Taylor, Kent D; Li, Guo; Evans, Daniel S; Smith, Albert V; de Keyser, Catherine E; Johnson, Andrew D; de Craen, Anton J M; Stott, David J; Buckley, Brendan M; Ford, Ian; Westendorp, Rudi G J; Slagboom, P Eline; Sattar, Naveed; Munroe, Patricia B; Sever, Peter; Poulter, Neil; Stanton, Alice; Shields, Denis C; O'Brien, Eoin; Shaw-Hawkins, Sue; Chen, Y-D Ida; Nickerson, Deborah A; Smith, Joshua D; Dubé, Marie Pierre; Boekholdt, S Matthijs; Hovingh, G Kees; Kastelein, John J P; McKeigue, Paul M; Betteridge, John; Neil, Andrew; Durrington, Paul N; Doney, Alex; Carr, Fiona; Morris, Andrew; McCarthy, Mark I; Groop, Leif; Ahlqvist, Emma; Bis, Joshua C; Rice, Kenneth; Smith, Nicholas L; Lumley, Thomas; Whitsel, Eric A; Stürmer, Til; Boerwinkle, Eric; Ngwa, Julius S; O'Donnell, Christopher J; Vasan, Ramachandran S; Wei, Wei-Qi; Wilke, Russell A; Liu, Ching-Ti; Sun, Fangui; Guo, Xiuqing; Heckbert, Susan R; Post, Wendy; Sotoodehnia, Nona; Arnold, Alice M; Stafford, Jeanette M; Ding, Jingzhong; Herrington, David M; Kritchevsky, Stephen B; Eiriksdottir, Gudny; Launer, Leonore J; Harris, Tamara B; Chu, Audrey Y; Giulianini, Franco; MacFadyen, Jean G; Barratt, Bryan J; Nyberg, Fredrik; Stricker, Bruno H; Uitterlinden, André G; Hofman, Albert; Rivadeneira, Fernando; Emilsson, Valur; Franco, Oscar H; Ridker, Paul M; Gudnason, Vilmundur; Liu, Yongmei; Denny, Joshua C; Ballantyne, Christie M; Rotter, Jerome I; Adrienne Cupples, L; Psaty, Bruce M; Palmer, Colin N A; Tardif, Jean-Claude; Colhoun, Helen M; Hitman, Graham; Krauss, Ronald M; Wouter Jukema, J; Caulfield, Mark J

    2014-01-01

    Statins effectively lower LDL cholesterol levels in large studies and the observed interindividual response variability may be partially explained by genetic variation. Here we perform a pharmacogenetic meta-analysis of genome-wide association studies (GWAS) in studies addressing the LDL cholesterol response to statins, including up to 18,596 statin-treated subjects. We validate the most promising signals in a further 22,318 statin recipients and identify two loci, SORT1/CELSR2/PSRC1 and SLCO1B1, not previously identified in GWAS. Moreover, we confirm the previously described associations with APOE and LPA. Our findings advance the understanding of the pharmacogenetic architecture of statin response. PMID:25350695

  3. Pharmacogenetic meta-analysis of genome-wide association studies of LDL cholesterol response to statins

    PubMed Central

    Postmus, Iris; Trompet, Stella; Deshmukh, Harshal A.; Barnes, Michael R.; Li, Xiaohui; Warren, Helen R.; Chasman, Daniel I.; Zhou, Kaixin; Arsenault, Benoit J.; Donnelly, Louise A.; Wiggins, Kerri L.; Avery, Christy L.; Griffin, Paula; Feng, QiPing; Taylor, Kent D.; Li, Guo; Evans, Daniel S.; Smith, Albert V.; de Keyser, Catherine E.; Johnson, Andrew D.; de Craen, Anton J. M.; Stott, David J.; Buckley, Brendan M.; Ford, Ian; Westendorp, Rudi G. J.; Eline Slagboom, P.; Sattar, Naveed; Munroe, Patricia B.; Sever, Peter; Poulter, Neil; Stanton, Alice; Shields, Denis C.; O’Brien, Eoin; Shaw-Hawkins, Sue; Ida Chen, Y.-D.; Nickerson, Deborah A.; Smith, Joshua D.; Pierre Dubé, Marie; Matthijs Boekholdt, S.; Kees Hovingh, G.; Kastelein, John J. P.; McKeigue, Paul M.; Betteridge, John; Neil, Andrew; Durrington, Paul N.; Doney, Alex; Carr, Fiona; Morris, Andrew; McCarthy, Mark I.; Groop, Leif; Ahlqvist, Emma; Bis, Joshua C.; Rice, Kenneth; Smith, Nicholas L.; Lumley, Thomas; Whitsel, Eric A.; Stürmer, Til; Boerwinkle, Eric; Ngwa, Julius S.; O’Donnell, Christopher J.; Vasan, Ramachandran S.; Wei, Wei-Qi; Wilke, Russell A.; Liu, Ching-Ti; Sun, Fangui; Guo, Xiuqing; Heckbert, Susan R; Post, Wendy; Sotoodehnia, Nona; Arnold, Alice M.; Stafford, Jeanette M.; Ding, Jingzhong; Herrington, David M.; Kritchevsky, Stephen B.; Eiriksdottir, Gudny; Launer, Leonore J.; Harris, Tamara B.; Chu, Audrey Y.; Giulianini, Franco; MacFadyen, Jean G.; Barratt, Bryan J.; Nyberg, Fredrik; Stricker, Bruno H.; Uitterlinden, André G.; Hofman, Albert; Rivadeneira, Fernando; Emilsson, Valur; Franco, Oscar H.; Ridker, Paul M.; Gudnason, Vilmundur; Liu, Yongmei; Denny, Joshua C.; Ballantyne, Christie M.; Rotter, Jerome I.; Adrienne Cupples, L.; Psaty, Bruce M.; Palmer, Colin N. A.; Tardif, Jean-Claude; Colhoun, Helen M.; Hitman, Graham; Krauss, Ronald M.; Wouter Jukema, J; Caulfield, Mark J.; Donnelly, Peter; Barroso, Ines; Blackwell, Jenefer M.; Bramon, Elvira; Brown, Matthew A.; Casas, Juan P.; Corvin, Aiden; Deloukas, Panos; Duncanson, Audrey; Jankowski, Janusz; Markus, Hugh S.; Mathew, Christopher G.; Palmer, Colin N. A.; Plomin, Robert; Rautanen, Anna; Sawcer, Stephen J.; Trembath, Richard C.; Viswanathan, Ananth C.; Wood, Nicholas W.; Spencer, Chris C. A.; Band, Gavin; Bellenguez, Céline; Freeman, Colin; Hellenthal, Garrett; Giannoulatou, Eleni; Pirinen, Matti; Pearson, Richard; Strange, Amy; Su, Zhan; Vukcevic, Damjan; Donnelly, Peter; Langford, Cordelia; Hunt, Sarah E.; Edkins, Sarah; Gwilliam, Rhian; Blackburn, Hannah; Bumpstead, Suzannah J.; Dronov, Serge; Gillman, Matthew; Gray, Emma; Hammond, Naomi; Jayakumar, Alagurevathi; McCann, Owen T.; Liddle, Jennifer; Potter, Simon C.; Ravindrarajah, Radhi; Ricketts, Michelle; Waller, Matthew; Weston, Paul; Widaa, Sara; Whittaker, Pamela; Barroso, Ines; Deloukas, Panos; Mathew, Christopher G.; Blackwell, Jenefer M.; Brown, Matthew A.; Corvin, Aiden; McCarthy, Mark I.; Spencer, Chris C. A.

    2014-01-01

    Statins effectively lower LDL cholesterol levels in large studies and the observed interindividual response variability may be partially explained by genetic variation. Here we perform a pharmacogenetic meta-analysis of genome-wide association studies (GWAS) in studies addressing the LDL cholesterol response to statins, including up to 18,596 statin-treated subjects. We validate the most promising signals in a further 22,318 statin recipients and identify two loci, SORT1/CELSR2/PSRC1 and SLCO1B1, not previously identified in GWAS. Moreover, we confirm the previously described associations with APOE and LPA. Our findings advance the understanding of the pharmacogenetic architecture of statin response. PMID:25350695

  4. Human scavenger protein AIM increases foam cell formation and CD36-mediated oxLDL uptake.

    PubMed

    Amézaga, Núria; Sanjurjo, Lucía; Julve, Josep; Aran, Gemma; Pérez-Cabezas, Begoña; Bastos-Amador, Patricia; Armengol, Carolina; Vilella, Ramon; Escolà-Gil, Joan Carles; Blanco-Vaca, Francisco; Borràs, Francesc E; Valledor, Annabel F; Sarrias, Maria-Rosa

    2014-03-01

    AIM is expressed by macrophages in response to agonists of the nuclear receptors LXR/RXR. In mice, it acts as an atherogenic factor by protecting macrophages from the apoptotic effects of oxidized lipids. In humans, it is detected in atherosclerotic lesions, but no role related to atherosclerosis has been reported. This study aimed to investigate whether the role of hAIM extends beyond inhibiting oxidized lipid-induced apoptosis. To accomplish this goal, functional analysis with human monocytic THP1 cells and macrophages differentiated from peripheral blood monocytes were performed. It was found that hAIM reduced oxLDL-induced macrophage apoptosis and increased macrophage adhesion to endothelial ICAM-1 by enhancing LFA-1 expression. Furthermore, hAIM increased foam cell formation, as shown by Oil Red O and Nile Red staining, as well as quantification of cholesterol content. This was not a result of decreased reverse cholesterol transport, as hAIM did not affect the efflux significantly from [(3)H] Cholesterol-laden macrophages driven by plasma, apoA-I, or HDL2 acceptors. Rather, flow cytometry studies indicated that hAIM increased macrophage endocytosis of fluorescent oxLDL, which correlated with an increase in the expression of the oxLDLR CD36. Moreover, hAIM bound to oxLDL in ELISA and enhanced the capacity of HEK-293 cells expressing CD36 to endocytose oxLDL, as studied using immunofluorescence microscopy, suggesting that hAIM serves to facilitate CD36-mediated uptake of oxLDL. Our data represent the first evidence that hAIM is involved in macrophage survival, adhesion, and foam cell formation and suggest a significant contribution to atherosclerosis-related mechanisms in the macrophage. PMID:24295828

  5. Growth of Paecilomyces variotii in B0 (diesel), B100 (biodiesel) and B7 (blend), degradation and molecular detection.

    PubMed

    Gassen, J; Bento, F M; Frazzon, A P G; Ferrão, M F; Marroni, I V; Simonetti, A B

    2015-08-01

    The introduction of biodiesel to diesel may allow the fuel to be more susceptible to microorganism growth, especially during incorrect storage. To evaluate the effect of adding biodiesel in pure diesel on the growth of Paecilomyces variotii, microcosms containing pure diesel (B0), blend diesel/biodiesel (B7) and pure biodiesel (B100) were used. In microcosm with minimal mineral medium and B0, B7 or B100, after 60 days, the biomass (dry weight) formed at interface oil-water in B7 and B100 was significantly higher when compared to that of B0. Infrared analysis showed reduction of the carbonile fraction in B7 and B100 suggesting formation of intermediate compounds in B7. To monitor possible contamination of fuel storage tank by P. variotii samples were collected and analysed by specific-PCR assay for detection of P. variotii spores in the aqueous phase. This method was able to detect a minimum of 103 spores ml-1, corresponding to 0.0144 ng µl-1 of DNA. Specificity was tested against Aspergillus fumigatus and Pseudallescheria boydii. PMID:26421768

  6. ApoE: In Vitro Studies of a Small Molecule Effector.

    PubMed

    Mondal, Tridib; Wang, Hanliu; DeKoster, Gregory T; Baban, Berevan; Gross, Michael L; Frieden, Carl

    2016-05-10

    Apolipoprotein E4 (apoE4), one of three isoforms of apoE, is the major risk factor for developing late onset Alzheimer's disease. The only differences among these isoforms (apoE2, apoE3, and apoE4) are single amino acid changes. Yet these proteins are functionally very different. One approach to ameliorating the effect of apoE4 with respect to Alzheimer's disease would be to find small molecular weight compounds that affect the behavior of apoE4. Few studies of this approach have been carried out in part because there was no complete structure of any full-length apoE isoform until 2011. Here, we focus on one small molecular weight compound, EZ-482, and explore the effects of its binding to apoE. Using hydrogen-deuterium exchange, we determined that EZ-482 binds to the C-terminal domains of both apoE3 and apoE4. The binding to apoE4, however, is accompanied by a unique N-terminal allosteric effect. Using fluorescence methods, we determined an apparent dissociation constant of approximately 8 μM. Although EZ-482 binds to the C-terminal domain, it blocks heparin binding to the N-terminal domain. The residues of apoE that bind heparin are the same as those involved in apoE binding to LDL and LRP-1 receptors. The methods and the data presented here may serve as a template for future studies using small molecular weight compounds to modulate the behavior of apoE. PMID:27065061

  7. Clinical Significance of the Humoral Immune Response to Modified LDL

    PubMed Central

    Lopes-Virella, MF; Virella, G

    2009-01-01

    Human low density lipoprotein (LDL) undergoes oxidation and glycation in vivo. By themselves, oxidized LDL (oxLDL) and AGE-LDL have proinflammatory properties and are considered atherogenic. But the atherogenicity of these lipoproteins are significantly increased as a consequence of the formation of immune complexes (IC) involving autoantibodies spontaneously formed. OxLDL and AGE antibodies have been shown to be predominantly of the IgG1 and IgG3 isotypes. OxLDL antibodies are able to activate the complement system by the classical pathway and to induce FcR-mediated phagocytosis. In vitro and ex vivo studies performed with modified LDL-IC have proven their pro-inflammatory and atherogenic properties. Clinical studies have demonstrated that the levels of circulating modified LDL-IC correlate with parameters indicative of cardiovascular and renal disease in diabetic patients and other patient populations. The possibility that spontaneously formed or induced modified LDL antibodies (particularly IgM oxLDL antibodies) may have a protective effect has been suggested, but the data is unclear and needs to be further investigated. PMID:19427818

  8. Oxidized LDL (oxLDL) activates the angiotensin II type 1 receptor by binding to the lectin-like oxLDL receptor.

    PubMed

    Yamamoto, Koichi; Kakino, Akemi; Takeshita, Hikari; Hayashi, Norihiro; Li, Lei; Nakano, Atsushi; Hanasaki-Yamamoto, Hiroko; Fujita, Yoshiko; Imaizumi, Yuki; Toyama-Yokoyama, Serina; Nakama, Chikako; Kawai, Tatsuo; Takeda, Masao; Hongyo, Kazuhiro; Oguro, Ryosuke; Maekawa, Yoshihiro; Itoh, Norihisa; Takami, Yoichi; Onishi, Miyuki; Takeya, Yasushi; Sugimoto, Ken; Kamide, Kei; Nakagami, Hironori; Ohishi, Mitsuru; Kurtz, Theodore W; Sawamura, Tatsuya; Rakugi, Hiromi

    2015-08-01

    The angiotensin II type 1 receptor (AT1) is a 7-transmembrane domain GPCR that when activated by its ligand angiotensin II, generates signaling events promoting vascular dysfunction and the development of cardiovascular disease. Here, we show that the single-transmembrane oxidized LDL (oxLDL) receptor (LOX-1) resides in proximity to AT1 on cell-surface membranes and that binding of oxLDL to LOX-1 can allosterically activate AT1-dependent signaling events. oxLDL-induced signaling events in human vascular endothelial cells were abolished by knockdown of AT1 and inhibited by AT1 blockade (ARB). oxLDL increased cytosolic G protein by 350% in Chinese hamster ovary (CHO) cells with genetically induced expression of AT1 and LOX-1, whereas little increase was observed in CHO cells expressing only LOX-1. Immunoprecipitation and in situ proximity ligation assay (PLA) assays in CHO cells revealed the presence of cell-surface complexes involving LOX-1 and AT1. Chimeric analysis showed that oxLDL-induced AT1 signaling events are mediated via interactions between the intracellular domain of LOX-1 and AT1 that activate AT1. oxLDL-induced impairment of endothelium-dependent vascular relaxation of vascular ring from mouse thoracic aorta was abolished by ARB or genetic deletion of AT1. These findings reveal a novel pathway for AT1 activation and suggest a new mechanism whereby oxLDL may be promoting risk for cardiovascular disease. PMID:25877213

  9. PCSK9 inhibition fails to alter hepatic LDLR, circulating cholesterol, and atherosclerosis in the absence of ApoE[S

    PubMed Central

    Ason, Brandon; van der Hoorn, José W. A.; Chan, Joyce; Lee, Edward; Pieterman, Elsbet J.; Nguyen, Kathy Khanh; Di, Mei; Shetterly, Susan; Tang, Jie; Yeh, Wen-Chen; Schwarz, Margrit; Jukema, J. Wouter; Scott, Rob; Wasserman, Scott M.; Princen, Hans M. G.; Jackson, Simon

    2014-01-01

    LDL cholesterol (LDL-C) contributes to coronary heart disease. Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases LDL-C by inhibiting LDL-C clearance. The therapeutic potential for PCSK9 inhibitors is highlighted by the fact that PCSK9 loss-of-function carriers exhibit 15–30% lower circulating LDL-C and a disproportionately lower risk (47–88%) of experiencing a cardiovascular event. Here, we utilized pcsk9−/− mice and an anti-PCSK9 antibody to study the role of the LDL receptor (LDLR) and ApoE in PCSK9-mediated regulation of plasma cholesterol and atherosclerotic lesion development. We found that circulating cholesterol and atherosclerotic lesions were minimally modified in pcsk9−/− mice on either an LDLR- or ApoE-deficient background. Acute administration of an anti-PCSK9 antibody did not reduce circulating cholesterol in an ApoE-deficient background, but did reduce circulating cholesterol (−45%) and TGs (−36%) in APOE*3Leiden.cholesteryl ester transfer protein (CETP) mice, which contain mouse ApoE, human mutant APOE3*Leiden, and a functional LDLR. Chronic anti-PCSK9 antibody treatment in APOE*3Leiden.CETP mice resulted in a significant reduction in atherosclerotic lesion area (−91%) and reduced lesion complexity. Taken together, these results indicate that both LDLR and ApoE are required for PCSK9 inhibitor-mediated reductions in atherosclerosis, as both are needed to increase hepatic LDLR expression. PMID:25258384

  10. Effects of LDL Receptor Modulation on Lymphatic Function

    PubMed Central

    Milasan, Andreea; Dallaire, François; Mayer, Gaétan; Martel, Catherine

    2016-01-01

    Atherosclerosis is driven by the accumulation of immune cells and cholesterol in the arterial wall. Although recent studies have shown that lymphatic vessels play an important role in macrophage reverse cholesterol transport, the specific underlying mechanisms of this physiological feature remain unknown. In the current report, we sought to better characterize the lymphatic dysfunction that is associated with atherosclerosis by studying the physiological and temporal origins of this impairment. First, we assessed that athero-protected Pcsk9−/− mice exhibited improved collecting lymphatic vessel function throughout age when compared to WT mice for up to six months, while displaying enhanced expression of LDLR on lymphatic endothelial cells. Lymphatic dysfunction was present before the atherosclerotic lesion formation in a mouse model that is predisposed to develop atherosclerosis (Ldlr−/−; hApoB100+/+). This dysfunction was presumably associated with a defect in the collecting lymphatic vessels in a non-specific cholesterol- but LDLR-dependent manner. Treatment with a selective VEGFR-3 agonist rescued this impairment observed early in the onset of this arterial disease. We suggest that LDLR modulation is associated with early atherosclerosis-related lymphatic dysfunction, and bring forth a pleiotropic role for PCSK9 in lymphatic function. Our study unveils new potential therapeutic targets for the prevention and treatment of atherosclerosis. PMID:27279328

  11. LDL immune complexes stimulate LDL receptor expression in U937 histiocytes via extracellular signal-regulated kinase and AP-1.

    PubMed

    Fu, Yuchang; Huang, Yan; Bandyopadhyay, Sumita; Virella, Gabriel; Lopes-Virella, Maria F

    2003-07-01

    We have previously shown that LDL-containing immune complexes (LDL-ICs) induce up-regulation of LDL receptor (LDLR) expression in human macrophages. The present study further investigated the molecular mechanisms leading to LDLR up-regulation by LDL-ICs as well as the signaling pathways involved. Results showed that treatment of U937 histiocytes with LDL-ICs did not increase the precursors and the cleaved forms of sterol-regulatory element binding proteins (SREBPs) 1a and 2, suggesting that SREBPs may not be involved in LDLR up-regulation by LDL-ICs. Promoter deletion and mutation studies showed that the AP-1 binding sites were essential for LDL-IC-stimulated LDLR expression. Electrophoretic mobility shift assays further demonstrated that LDL-ICs stimulated transcription factor AP-1 activity. Studies assessing the signaling pathways involved in LDLR up-regulation by LDL-ICs showed that the up-regulation of LDLR was extracellular signal-regulated kinase (ERK) dependent. In conclusion, the present study shows that LDL-ICs up-regulate LDLR expression via the ERK signaling pathway and the AP-1 motif-dependent transcriptional activation. PMID:12730303

  12. High-oleic canola oil consumption enriches LDL particle cholesteryl oleate content and reduces LDL proteoglycan binding in humans

    PubMed Central

    Jones, Peter J. H.; MacKay, Dylan. S.; Senanayake, Vijitha K.; Pu, Shuaihua; Jenkins, David J. A.; Connelly, Philip W.; Lamarche, Benoît; Couture, Patrick; Kris-Etherton, Penny M.; West, Sheila G.; Liu, Xiaoran; Fleming, Jennifer A.; Hantgan, Roy R.; Rudel, Lawrence L.

    2015-01-01

    Oleic acid consumption is considered cardio-protective according to studies conducted examining effects of the Mediterranean diet. However, animal models have shown that oleic acid consumption increases LDL particle cholesteryl oleate content which is associated with increased LDL-proteoglycan binding and atherosclerosis. The objective was to examine effects of varying oleic, linoleic and docosahexaenoic acid consumption on human LDL-proteoglycan binding in a non-random subset of the Canola Oil Multi-center Intervention Trial (COMIT) participants. COMIT employed a randomized, double-blind, five-period, cross-over trial design. Three of the treatment oil diets; 1) a blend of corn/safflower oil (25:75); 2) high oleic canola oil; and 3) DHA-enriched high oleic canola oil were selected for analysis of LDL-proteoglycan binding in 50 participants exhibiting good compliance. LDL particles were isolated from frozen plasma by gel filtration chromatography and LDL cholesteryl esters quantified by mass-spectrometry. LDL-proteoglycan binding was assessed using surface plasmon resonance. LDL particle cholesterol ester fatty acid composition was sensitive to the treatment fatty acid compositions, with the main fatty acids in the treatments increasing in the LDL cholesterol esters. The corn/safflower oil and high-oleic canola oil diets lowered LDL-proteoglycan binding relative to their baseline values (p=0.0005 and p=0.0012, respectively). At endpoint, high-oleic canola oil feeding resulted in lower LDL-proteoglycan binding than corn/safflower oil (p=0.0243) and DHA-enriched high oleic canola oil (p=0.0249), although high-oleic canola oil had the lowest binding at baseline (p=0.0344). Our findings suggest that high-oleic canola oil consumption in humans increases cholesteryl oleate percentage in LDL, but in a manner not associated with a rise in LDL-proteoglycan binding. PMID:25528432

  13. High-oleic canola oil consumption enriches LDL particle cholesteryl oleate content and reduces LDL proteoglycan binding in humans.

    PubMed

    Jones, Peter J H; MacKay, Dylan S; Senanayake, Vijitha K; Pu, Shuaihua; Jenkins, David J A; Connelly, Philip W; Lamarche, Benoît; Couture, Patrick; Kris-Etherton, Penny M; West, Sheila G; Liu, Xiaoran; Fleming, Jennifer A; Hantgan, Roy R; Rudel, Lawrence L

    2015-02-01

    Oleic acid consumption is considered cardio-protective according to studies conducted examining effects of the Mediterranean diet. However, animal models have shown that oleic acid consumption increases LDL particle cholesteryl oleate content which is associated with increased LDL-proteoglycan binding and atherosclerosis. The objective was to examine effects of varying oleic, linoleic and docosahexaenoic acid consumption on human LDL-proteoglycan binding in a non-random subset of the Canola Oil Multi-center Intervention Trial (COMIT) participants. COMIT employed a randomized, double-blind, five-period, cross-over trial design. Three of the treatment oil diets: 1) a blend of corn/safflower oil (25:75); 2) high oleic canola oil; and 3) DHA-enriched high oleic canola oil were selected for analysis of LDL-proteoglycan binding in 50 participants exhibiting good compliance. LDL particles were isolated from frozen plasma by gel filtration chromatography and LDL cholesteryl esters quantified by mass-spectrometry. LDL-proteoglycan binding was assessed using surface plasmon resonance. LDL particle cholesterol ester fatty acid composition was sensitive to the treatment fatty acid compositions, with the main fatty acids in the treatments increasing in the LDL cholesterol esters. The corn/safflower oil and high-oleic canola oil diets lowered LDL-proteoglycan binding relative to their baseline values (p = 0.0005 and p = 0.0012, respectively). At endpoint, high-oleic canola oil feeding resulted in lower LDL-proteoglycan binding than corn/safflower oil (p = 0.0243) and DHA-enriched high oleic canola oil (p = 0.0249), although high-oleic canola oil had the lowest binding at baseline (p = 0.0344). Our findings suggest that high-oleic canola oil consumption in humans increases cholesteryl oleate percentage in LDL, but in a manner not associated with a rise in LDL-proteoglycan binding. PMID:25528432

  14. Dimyristoylphosphotidylcholine induces conformational changes in apoB that lowers lipoprotein(a)

    PubMed Central

    Wang, Yan-Ting; von Zychlinski, Anne; McCormick, Sally P. A.

    2009-01-01

    Lipoprotein(a) [Lp(a)] is assembled by the binding of apolipoprotein B (apoB) lysine residues on LDL to lysine binding sites in apolipoprotein(a) [apo(a)] and the subsequent formation of a disulphide bond between apoB and apo(a). In this study, we induced changes in apoB conformation by adding phospholipids to LDL and tested the effect of the altered apoB conformation on Lp(a) assembly. The addition of dimyristoylphosphatidylcholine (DMPC) to isolated LDL induced a decrease in the α-helical content of apoB and increased the immunoreactivity of the apoB C terminus toward monoclonal antibodies in the region. These conformational changes were associated with a reduction in the ability of the DMPC-modified LDL to form Lp(a) in in vitro assays. Furthermore, administration of DMPC to Lp(a) transgenic mice lead to a significant but transient decrease in Lp(a) levels (18.6% decrease at 2 h, P < 0.001) which coincided with the association of DMPC with LDL in plasma. Our study shows that changes in apoB conformation in the C-terminal region alter the exposure of sequences required for Lp(a) assembly and reduce the formation of Lp(a) both in vitro and in vivo. We conclude that manipulation of LDL surface phospholipids alters Lp(a) levels. PMID:19098283

  15. Interactions of Apolipoproteins AI, AII, B and HDL, LDL, VLDL with Polyurethane and Polyurethane-PEO Surfaces.

    PubMed

    Cornelius, R M; Macri, J; Cornelius, K M; Brash, J L

    2015-11-10

    The lipoproteins (HDL, LDL, VLDL) are important components of blood present in high concentration. Surprisingly, their role in blood-biomaterial interactions has been largely ignored. In previous work apolipoprotein AI (the main protein component of HDL) was identified as a major constituent of protein layers adsorbed from plasma to biomaterials having a wide range of surface properties, and quantitative data on the adsorption of apo AI to a biomedical grade polyurethane were reported. In the present communication quantitative data on the adsorption of apo AI, apo AII and apoB (the latter being a constituent of LDL and VLDL), as well as the lipoprotein particles themselves (HDL, LDL, VLDL), to a biomedical segmented polyurethane (PU) with and without an additive containing poly(ethylene oxide) (material referred to as PEO) are reported. Using radiolabeled apo AI, apo AII, and apoB, adsorption levels on PU from buffer at a protein concentration of 50 μg/mL were found to be 0.34, 0.40, and 0.14 μg/cm(2) (12, 23, and 0.25 nmol/cm(2)) respectively. Adsorption to the PEO surface was <0.02 μg/cm(2) for all three apolipoproteins demonstrating the strong protein resistance of this material. In contrast to the apolipoproteins, significant amounts of the lipoproteins were found to adsorb to the PEO as well as to the PU surface. X-ray photoelectron spectra, following exposure of the surfaces to the lipoproteins, showed a strong phosphorus signal, confirming that adsorption had occurred. It therefore appears that a PEO-containing surface that is resistant to apolipoproteins may be less resistant to the corresponding lipoproteins. PMID:26513526

  16. [PCSK9 Inhibitors - the magic bullet for LDL cholesterol reduction?].

    PubMed

    Richter, Kurt; Barthel, Andreas; Bornstein, Stefan R; El-Armouche, Ali; Wagner, Michael

    2016-06-01

    The proprotein convertase subtilisin / kexin type 9 (PCSK9) plays an important role in LDL cholesterol (LDL-C) metabolism. Subjects harboring loss-of-function mutations in the gene encoding for PCSK9 display markedly reduced LDL-C plasma levels. PCSK9 is secreted by the liver, binds to the LDL receptor and, following endocytosis, induces lysosomal degradation of the receptor together with the bound LDL-C. Current PCSK9 inhibitors are monoclonal antibodies that specifically absorb PCSK9. Subsequently, instead of being degraded the receptor can dissociate from LDL-C and recycle, consecutively resulting in an increased hepatocyte LDL receptor density and higher LDL-C clearance. In clinical trials, the PCSK9 inhibitors alirocumab and evolocumab induced reductions in LDL-C of up to 70 % in statin-treated as well as statin-naïve patients. So far, serious side effects (requiring cessation of drug treatment) occurred only in rare cases. Since this new class of lipid lowering drugs promises a high potential benefit, they have been approved by the EMA even before completion of the studies addressing clinically relevant endpoints like cardiovascular events and mortality. Therefore, the expected publication of these study results in 2017 may allow a better assessment of the efficacy and safety of PCSK9 inhibitors. PMID:27305302

  17. apoE3[K146N/R147W] acts as a dominant negative apoE form that prevents remnant clearance and inhibits the biogenesis of HDL.

    PubMed

    Fotakis, Panagiotis; Vezeridis, Alexander; Dafnis, Ioannis; Chroni, Angeliki; Kardassis, Dimitris; Zannis, Vassilis I

    2014-07-01

    The K146N/R147W substitutions in apoE3 were described in patients with a dominant form of type III hyperlipoproteinemia. The effects of these mutations on the in vivo functions of apoE were studied by adenovirus-mediated gene transfer in different mouse models. Expression of the apoE3[K146N/R147W] mutant in apoE-deficient (apoE(-/-)) or apoA-I-deficient (apoA-I(-/-))×apoE(-/-) mice exacerbated the hypercholesterolemia and increased plasma apoE and triglyceride levels. In apoE(-/-) mice, the apoE3[K146N/R147W] mutant displaced apoA-I from the VLDL/LDL/HDL region and caused the accumulation of discoidal apoE-containing HDL. The WT apoE3 cleared the cholesterol of apoE(-/-) mice without induction of hypertriglyceridemia and promoted formation of spherical HDL. A unique property of the truncated apoE3[K146N/R147W]202 mutant, compared with similarly truncated apoE forms, is that it did not correct the hypercholesterolemia. The contribution of LPL and LCAT in the induction of the dyslipidemia was studied. Treatment of apoE(-/-) mice with apoE3[K146N/R147W] and LPL corrected the hypertriglyceridemia, but did not prevent the formation of discoidal HDL. Treatment with LCAT corrected hypertriglyceridemia and generated spherical HDL. The combined data indicate that the K146N/R147W substitutions convert the full-length and the truncated apoE3[K146N/R147W] mutant into a dominant negative ligand that prevents receptor-mediated remnant clearance, exacerbates the dyslipidemia, and inhibits the biogenesis of HDL. PMID:24776540

  18. Postprandial dyslipidemia in men with visceral obesity: an effect of reduced LDL receptor expression?

    PubMed

    Mamo, J C; Watts, G F; Barrett, P H; Smith, D; James, A P; Pal, S

    2001-09-01

    Postprandial lipemia after an oral fat challenge was studied in middle-aged men with visceral obesity. The two groups had similar plasma cholesterol levels, but obese subjects had higher levels of plasma triglyceride and reduced amounts of high-density cholesterol. Fasting plasma insulin was fourfold greater in obese subjects because of concomitant insulin resistance, with a calculated HOMA score of 3.1 +/- 0.6 vs. 0.8 +/- 0.2, respectively. Plasma apolipoprotein B(48) (apoB(48)) and retinyl palmitate (RP) after an oral fat challenge were used to monitor chylomicron metabolism. Compared with lean subjects, the fasting concentration of apoB(48) was more than twofold greater in obese individuals, suggestive of an accumulation of posthydrolyzed particles. After the oral lipid load, the incremental areas under the apoB(48) and RP curves (IAUC) were both significantly greater in obese subjects (apoB(48): 97 +/- 17 vs. 44 +/- 12 microg.ml(-1). h; RP: 3,120 +/- 511 vs. 1,308 +/- 177 U. ml(-1). h, respectively). A delay in the conversion of chylomicrons to remnants probably contributed to postprandial dyslipidemia in viscerally obese subjects. The triglyceride IAUC was 68% greater in obese subjects (4.7 +/- 0.6 vs. 2.8 +/- 0.8 mM. h, P < 0.06). Moreover, peak postprandial triglyceride was delayed by approximately 2 h in obese subjects. The reduction in triglyceride lipolysis in vivo did not appear to reflect changes in hydrolytic enzyme activities. Postheparin plasma lipase rates were found to be similar for lean and obese subjects. In this study, low-density lipoprotein (LDL) receptor expression on monunuclear cells was used as a surrogate marker of hepatic activity. We found that, in obese subjects, the binding of LDL was reduced by one-half compared with lean controls (70.9 +/- 15.07 vs. 38.9 +/- 4.6 ng LDL bound/microg cell protein, P = 0.02). Because the LDL receptor is involved in the removal of proatherogenic chylomicron remnants, we suggest that the hepatic

  19. Reduced concentrations of apolipoproteins B-100 and A-I in serum from cows with retained placenta.

    PubMed Central

    Oikawa, S; Katoh, N

    1997-01-01

    The purpose of the present study was to evaluate apolipoprotein B-100 and A-I concentrations in cows with retained placenta. Animals used were cows with retained placenta alone (n = 10), those with both retained placenta and ketosis (n = 7), and controls (n = 10). Apolipoprotein B-100 concentrations at 2 to 4 d after parturition were significantly (P < 0.01) decreased in cows with retained placenta alone (mean +/- SD, 0.084 +/- 0.029 mg/ML of serum) when compared with those in control cows (0.154 +/- 0.022 mg/mL). Apolipoprotein A-I concentrations (0.713 +/- 0.177 mg/ML) were also significantly (P < 0.05) lower than those of controls (0.895 +/- 0.159 mg/mL). These decreases were more distinct for apolipoproteins B-100 (55% of controls) than A-I concentrations (80% of controls). Concentrations of apolipoprotein B-100 (0.071 +/- 0.032 mg/mL; P < 0.01) and A-I (0.708 +/- 0.189 mg/mL; P < 0.05) in the cows with both retained placenta and ketosis were also reduced, when compared with values in controls. Other than apolipoproteins, cows with retained placenta alone had significantly (P < 0.01) higher serum nonesterified fatty acids, and lower triglyceride concentrations. Significantly (P < 0.01) higher nonesterified fatty acids and lower triglyceride concentrations were similarly observed in cows with both retained placenta and ketosis. PMID:9342458

  20. The Effect of a Shear Flow on the Uptake of LDL and Ac-LDL by Cultured Vascular Endothelial Cells

    NASA Astrophysics Data System (ADS)

    Niwa, Koichi; Karino, Takeshi

    The effects of a shear flow on the uptake of fluorescence-labeled low-density lipoprotein (DiI-LDL), acetylated LDL (DiI-Ac-LDL), and lucifer yellow (LY; a tracer of fluid-phase endocytosis) by cultured bovine aortic ECs were studied using a rotating-disk shearing apparatus. It was found that 2hours’ exposure of ECs to a laminar shear flow that imposed ECs an area-mean shear stress of 10dynes/cm2 caused an increase in the uptake of DiI-LDL and LY. By contrast, the uptake of DiI-Ac-LDL was decreased by exposure of the ECs to a shear flow. Addition of dextran sulfate (DS), a competitive inhibitor of scavenger receptors, reversed the effect of a shear flow on the uptake of DiI-Ac-LDL, resulting in an increase by the imposition of a shear flow, while the uptake of DiI-LDL and LY remained unaffected. It was concluded that a shear flow promotes the endocytosis of DiI-LDL and LY by ECs, but suppresses the uptake of DiI-Ac-LDL by ECs by inhibiting scavenger receptor-mediated endocytosis.

  1. Genetic variants of ApoE account for variability of plasma low-density lipoprotein and apolipoprotein B levels in FHBL.

    PubMed

    Yue, Pin; Isley, William L; Harris, William S; Rosipal, Stefan; Akin, Carl D; Schonfeld, Gustav

    2005-01-01

    We report two novel APOB mutations causing short apolipoprotein B (apoB) truncations undetectable in plasma and familial hypobetalipoproteinemia (FHBL). In Family 56, a 5 bp deletion in APOB exon 7 (870_874del5) causes a frame shift, converting tyrosine to a stop codon (Y220X) and producing an apoB-5 truncation. In Family 59, a point mutation (1941G>T) in APOB exon 13 converts glutamic acid to stop codon (E578X), specifying apoB-13. A recurrent mutation in exon 26 (4432delT) produces apoB-30.9 in Family 58. In some members of these families, we observed that plasma low-density lipoprotein (LDL) cholesterol and apoB levels were unusually low even for subjects heterozygous for FHBL. To ascertain whether genetic variations in apolipoprotein E (apoE) would explain some of the variations of apoB and LDL cholesterol levels, apoE genotypes were assessed in affected subjects from a total of eight FHBL families with short apoB truncations. Heterozygous FHBL with the epsilon3/epsilon4 genotype had 10-1 5mg/dL higher plasma LDL cholesterol and apoB levels compared to subjects with the epsilon2/epsilon3 and epsilon3/epsilon3 genotypes. The apoE genotype has been reported to account for approximately 10% of the variation of LDL cholesterol in the general population. It accounted for 15-60% of the variability of plasma LDL cholesterol or apoB levels in our FHBL subjects. The physiologic bases for the greater effects of apoE in FHBL remain to be determined. PMID:15585207

  2. LDL apheresis and inflammation--implications for atherosclerosis.

    PubMed

    Hovland, A; Lappegård, K T; Mollnes, T E

    2012-09-01

    Low-density lipoprotein (LDL) apheresis is an extracorporeal treatment modality used in high-risk patients when LDL cholesterol levels cannot be reduced adequately with medication. The treatment is highly effective, but could be affected by potential unwanted effects on pro- and anti-inflammatory biomarkers. In this paper, we review the literature regarding the effect of LDL apheresis on pro- and anti-inflammatory biomarkers important in atherosclerosis, also as patients in LDL apheresis have high risk for atherosclerotic complications. We discuss the effect of LDL apheresis on complement, cytokines and finally a group of other selected pro- and anti-inflammatory biomarkers. The complement system is affected by LDL apheresis, and there are differences between different LDL apheresis systems. The plasma separation columns seem to trigger the formation of proinflammatory complement factors including C3a and C5a, while the same anaphylatoxins are adsorbed by the LDL apheresis columns, however, to varying degree. Proinflammatory cytokines are to some extent adsorbed by the LDL apheresis columns, while some of the anti-inflammatory cytokines increase during treatment. Finally, we discuss the effect of apheresis on different biomarkers including C-reactive protein, fibrinogen, adhesion molecules, myeloperoxidase and HDL cholesterol. In conclusion, even if there are differences between pro- and anti-inflammatory biomarkers during LDL apheresis, the consequences for the patients are largely unknown and larger studies need to be performed. Preferably, they should be comparing the effect of different LDL apheresis columns on the total inflammatory profile, and this should be related to clinical endpoints. PMID:22670805

  3. Role of LDL cholesterol and endolysosomes in amyloidogenesis and Alzheimer's disease

    PubMed Central

    Chen, Xuesong; Hui, Liang; Geiger, Jonathan D.

    2015-01-01

    The pathogenesis of late-onset sporadic Alzheimer's disease (AD) is believed to result from complex interactions between nutritional, environmental, epigenetic and genetic factors. Among those factors, altered circulating cholesterol homeostasis, independent of the APOE genotype, continues to be implicated in brain deposition of amyloid beta protein (Aβ) and the pathogenesis of AD. It is believed that trafficking of amyloid beta precursor protein (AβPP) into endolysosomes appears to play a critical role in determining amyloidogenic processing of AβPP because this is precisely where two enzymes critically important in AβPP metabolism are located; beta amyloid converting enzyme (BACE-1) and gamma secretase enzyme. We have shown that elevated levels of LDL cholesterol promote AβPP internalization, disturb neuronal endolysosome structure and function, and increase Aβ accumulation in neuronal endolysosomes. Here, we will further discuss the linkage between elevated levels of LDL cholesterol and AD pathogenesis, and explore the underlying mechanisms whereby elevated levels of plasma LDL cholesterol promote amyloidogenesis. PMID:26413387

  4. LDL and HDL transfer rates across peripheral microvascular endothelium agree with those predicted for passive ultrafiltration in humans

    PubMed Central

    Michel, C. Charles; Nanjee, M. Nazeem; Olszewski, Waldemar L.; Miller, Norman E.

    2015-01-01

    The mechanisms by which LDLs and HDLs cross the vascular endothelium from plasma into interstitial fluid are not understood, and have never been studied in humans in vivo. We determined whether the plasma-to-lymph clearance rates of LDL and HDL conform with those predicted by passive ultrafiltration through intercellular pores, or if it is necessary to invoke an active process such as receptor-mediated transcytosis. Plasma and afferent peripheral lymph were collected under steady-state conditions from 30 healthy men, and assayed for seven globular proteins of molecular radii 2.89–8.95 nm, complement C3, and apo AI, apo AII, and apo B. Plasma-to-lymph clearance rates of the seven proteins fitted the relation expected for molecules of their size when transported through two populations of pores of radius 4.95 and 20.1 nm. The same model parameters were then found to accurately predict the clearance rates of both HDL and LDL. The apparent clearance of complement C3, previously shown to be secreted by cultured endothelium, exceeded that predicted by the model. We conclude that the transport of HDL and LDL from plasma into interstitial fluid across the peripheral vascular endothelium in healthy humans can be explained by ultrafiltration without invoking an additional active process such as transcytosis. PMID:25398615

  5. Hepatic sortilin regulates both apolipoprotein B secretion and LDL catabolism

    PubMed Central

    Strong, Alanna; Ding, Qiurong; Edmondson, Andrew C.; Millar, John S.; Sachs, Katherine V.; Li, Xiaoyu; Kumaravel, Arthi; Wang, Margaret Ye; Ai, Ding; Guo, Liang; Alexander, Eric T.; Nguyen, David; Lund-Katz, Sissel; Phillips, Michael C.; Morales, Carlos R.; Tall, Alan R.; Kathiresan, Sekar; Fisher, Edward A.; Musunuru, Kiran; Rader, Daniel J.

    2012-01-01

    Genome-wide association studies (GWAS) have identified a genetic variant at a locus on chromosome 1p13 that is associated with reduced risk of myocardial infarction, reduced plasma levels of LDL cholesterol (LDL-C), and markedly increased expression of the gene sortilin-1 (SORT1) in liver. Sortilin is a lysosomal sorting protein that binds ligands both in the Golgi apparatus and at the plasma membrane and traffics them to the lysosome. We previously reported that increased hepatic sortilin expression in mice reduced plasma LDL-C levels. Here we show that increased hepatic sortilin not only reduced hepatic apolipoprotein B (APOB) secretion, but also increased LDL catabolism, and that both effects were dependent on intact lysosomal targeting. Loss-of-function studies demonstrated that sortilin serves as a bona fide receptor for LDL in vivo in mice. Our data are consistent with a model in which increased hepatic sortilin binds intracellular APOB-containing particles in the Golgi apparatus as well as extracellular LDL at the plasma membrane and traffics them to the lysosome for degradation. We thus provide functional evidence that genetically increased hepatic sortilin expression both reduces hepatic APOB secretion and increases LDL catabolism, providing dual mechanisms for the very strong association between increased hepatic sortilin expression and reduced plasma LDL-C levels in humans. PMID:22751103

  6. Overview: techniques and indications of LDL-apheresis.

    PubMed

    Bosch, T; Gurland, H J

    1991-01-01

    In recent years, LDL-apheresis has emerged to be an efficient treatment of hyperlipidemia in patients who do not respond sufficiently to diet and lipid lowering drugs. A survey of LDL lowering extracorporeal procedures is presented. Among them, to date 5 procedures have been used clinically on a routine basis: unselective plasma exchange, semi-selective double filtration (including its modifications like thermofiltration and predilution/backflush) and three highly selective LDL-apheresis systems: LDL-adsorption on dextran sulfate coated cellulose beads or anti-apoprotein B-linked sepharose and heparin induced extracorporeal LDL and fibrinogen precipitation (the so-called HELP system). Advantages, limitations and special indications of these commercially available systems are discussed. If atherosclerosis can really be made regress by drastic reduction of elevated serum cholesterol levels as indicated by recent publications, lipid apheresis will no doubt play a major role in attaining this goal. PMID:1751662

  7. Accumulation of Oxidized LDL in the Tendon Tissues of C57BL/6 or Apolipoprotein E Knock-Out Mice That Consume a High Fat Diet: Potential Impact on Tendon Health

    PubMed Central

    Grewal, Navdeep; Thornton, Gail M.; Behzad, Hayedeh; Sharma, Aishwariya; Lu, Alex; Zhang, Peng; Reid, W. Darlene; Granville, David J.; Scott, Alex

    2014-01-01

    Objective Clinical studies have suggested an association between dyslipidemia and tendon injuries or chronic tendon pain; the mechanisms underlying this association are not yet known. The objectives of this study were (1) to evaluate the impact of a high fat diet on the function of load-bearing tendons and on the distribution in tendons of oxidized low density lipoprotein (oxLDL), and (2) to examine the effect of oxLDL on tendon fibroblast proliferation and gene expression. Methods Gene expression (Mmp2, Tgfb1, Col1a1, Col3a1), fat content (Oil Red O staining), oxLDL levels (immunohistochemistry) and tendon biomechanical properties were examined in mice (C57Bl/6 or ApoE -/-) receiving a standard or a high fat diet. Human tendon fibroblast proliferation and gene expression (COL1A1, COL3A1, MMP2) were examined following oxLDL exposure. Results In both types of mice (C57Bl/6 or ApoE -/-), consumption of a high fat diet led to a marked increase in oxLDL deposition in the load-bearing extracellular matrix of the tendon. The consumption of a high fat diet also reduced the failure stress and load of the patellar tendon in both mouse types, and increased Mmp2 expression. ApoE -/- mice exhibited more pronounced reductions in tendon function than wild-type mice, and decreased expression of Col1a1 compared to wild type mice. Human tendon fibroblasts responded to oxLDL by increasing their proliferation and their mRNA levels of MMP2, while decreasing their mRNA levels for COL1A1 and COL3A1. Conclusion The consumption of a high fat diet resulted in deleterious changes in tendon function, and these changes may be explained in part by the effects of oxLDL, which induced a proliferative, matrix-degrading phenotype in human tenocytes. PMID:25502628

  8. Observational study of lipid profile and LDL particle size in patients with metabolic syndrome

    PubMed Central

    2011-01-01

    Background The atherogenic lipoprotein phenotype is characterized by an increase in plasma triglycerides, a decrease in high-density lipoprotein cholesterol (HDLc), and the prevalence of small, dense-low density lipoprotein cholesterol (LDLc) particles. The aim of this study was to establish the importance of LDL particle size measurement by gender in a group of patients with Metabolic Syndrome (MS) attending at a Cardiovascular Risk Unit in Primary Care and their classification into phenotypes. Subjects and methods One hundred eighty-five patients (93 men and 92 women) from several areas in the South of Spain, for a period of one year in a health centre were studied. Laboratory parameters included plasma lipids, lipoproteins, low-density lipoprotein size and several atherogenic rates were determinated. Results We found differences by gender between anthropometric parameters, blood pressure and glucose measures by MS status. Lipid profile was different in our two study groups, and gender differences in these parameters within each group were also remarkable, in HDLc and Apo A-I values. According to LDL particle size, we found males had smaller size than females, and patients with MS had also smaller than those without MS. We observed inverse relationship between LDL particle size and triglycerides in patients with and without MS, and the same relationship between all atherogenic rates in non-MS patients. When we considered our population in two classes of phenotypes, lipid profile was worse in phenotype B. Conclusion In conclusion, we consider worthy the measurement of LDL particle size due to its relationship with lipid profile and cardiovascular risk. PMID:21936888

  9. Analogs of LDL Receptor Ligand Motifs in Dengue Envelope and Capsid Proteins as Potential Codes for Cell Entry

    PubMed Central

    Guevara, Juan; Romo, Jamie; McWhorter, Troy; Guevara, Natalia Valentinova

    2016-01-01

    It is established that cell entry of low density lipoprotein particles (LLPs) containing Apo B100 and Apo E is mediated by receptors and GAGs. Receptor ligand motifs, XBBBXXBX, XBBXBX, and ΨBΨXB, and mono- and bipartite NLS sequences are abundant in Apo E and Apo B100 as well as in envelope and capsid proteins of Dengue viruses 1–4 (DENV1–4). Synthetic, fluorescence-labeled peptides of sequences in DENV2 envelope protein, and DENV3 capsid that include these motifs were used to conduct a qualitative assessment of cell binding and entry capacity using HeLa cells. DENV2 envelope peptide, Dsp2EP, 0564Gly-Gly0595, was shown to bind and remain at the cell surface. In contrast, DENV3 capsid protein peptide, Dsp3CP, 0002Asn-Gln0028, readily enters HeLa cells and accumulates at discrete loci in the nucleus. FITC-labeled dengue synthetic peptides colocalize with Low Density Lipoprotein-CM-DiI and Apo E-CM-DiI to a degree that suggests that Dengue viruses may utilize cell entry pathways used by LLPs. PMID:27123468

  10. Myeloid Deletion of α1AMPK Exacerbates Atherosclerosis in LDL Receptor Knockout (LDLRKO) Mice.

    PubMed

    Cao, Qiang; Cui, Xin; Wu, Rui; Zha, Lin; Wang, Xianfeng; Parks, John S; Yu, Liqing; Shi, Hang; Xue, Bingzhong

    2016-06-01

    Macrophage inflammation marks all stages of atherogenesis, and AMPK is a regulator of macrophage inflammation. We therefore generated myeloid α1AMPK knockout (MAKO) mice on the LDL receptor knockout (LDLRKO) background to investigate whether myeloid deletion of α1AMPK exacerbates atherosclerosis. When fed an atherogenic diet, MAKO/LDLRKO mice displayed exacerbated atherosclerosis compared with LDLRKO mice. To determine the underlying pathophysiological pathways, we characterized macrophage inflammation/chemotaxis and lipid/cholesterol metabolism in MAKO/LDLRKO mice. Myeloid deletion of α1AMPK increased macrophage inflammatory gene expression and enhanced macrophage migration and adhesion to endothelial cells. Remarkably, MAKO/LDLRKO mice also displayed higher composition of circulating chemotaxically active Ly-6C(high) monocytes, enhanced atherosclerotic plaque chemokine expression, and monocyte recruitment into plaques, leading to increased atherosclerotic plaque macrophage content and inflammation. MAKO/LDLRKO mice also exhibited higher plasma LDL and VLDL cholesterol content, increased circulating apolipoprotein B (apoB) levels, and higher liver apoB expression. We conclude that macrophage α1AMPK deficiency promotes atherogenesis in LDLRKO mice and is associated with enhanced macrophage inflammation and hypercholesterolemia and that macrophage α1AMPK may serve as a therapeutic target for prevention and treatment of atherosclerosis. PMID:26822081

  11. Attenuation of monocyte adhesion and oxidised LDL uptake in luteolin-treated human endothelial cells exposed to oxidised LDL.

    PubMed

    Jeong, Yu-Jin; Choi, Yean-Jung; Choi, Jung-Suk; Kwon, Hyang-Mi; Kang, Sang-Wook; Bae, Ji-Young; Lee, Sang-Soo; Kang, Jung-Sook; Han, Seoung Jun; Kang, Young-Hee

    2007-03-01

    Oxidative modification of LDL is causally involved in the development of atherosclerosis and occurs in vivo in the blood as well as within the vascular wall. The present study attempted to explore whether polyphenolic flavonoids influence monocyte-endothelium interaction and lectin-like oxidised LDL receptor 1 (LOX-1) expression involved in the early development of atherosclerosis. The flavones luteolin and apigenin inhibited THP-1 cell adhesion onto oxidised LDL-activated human umbilical vein endothelial cells (HUVEC), while the flavanols of (-)epigallocatechin gallate and (+)catechin, the flavonols of quercetin and rutin, and the flavanones of naringin, naringenin, hesperidin and hesperetin did not have such effects. Consistently, Western blot analysis revealed that the flavones at 25 microM dramatically and significantly abolished HUVEC expression of vascular cell adhesion molecule-1 and E-selectin evidently enhanced by oxidised LDL; these inhibitory effects were exerted by drastically down regulating mRNA levels of these cell adhesion molecules. In addition, quercetin and luteolin significantly attenuated expression of LOX-1 protein up regulated in oxidised LDL-activated HUVEC with a fall in transcriptional mRNA levels of LOX-1. In addition, quercetin and luteolin clearly blunted oxidised LDL uptake by HUVEC treated with oxidised LDL. The results demonstrate that the flavones luteolin and apigenin as well as quercetin were effective in the different initial steps of atherosclerosis process by inhibiting oxidised LDL-induced endothelial monocyte adhesion and/or oxidised LDL uptake. Therefore, certain flavonoids qualify as anti-atherogenic agents in LDL systems, which may have implications for strategies attenuating endothelial dysfunction-related atherosclerosis. PMID:17313705

  12. TNF-α promotes early atherosclerosis by increasing transcytosis of LDL across endothelial cells: crosstalk between NF-κB and PPAR-γ.

    PubMed

    Zhang, Youzhi; Yang, Xiaoyan; Bian, Fang; Wu, Pinhui; Xing, Shasha; Xu, Gao; Li, Wenjing; Chi, Jiangyang; Ouyang, Changhan; Zheng, Tao; Wu, Dan; Zhang, Yonghui; Li, Yongsheng; Jin, Si

    2014-07-01

    Tumor necrosis factor-α (TNF-α) is an established pro-atherosclerotic factor, but the mechanism is not completely understood. We explored whether TNF-α could promote atherosclerosis by increasing the transcytosis of lipoproteins (e.g., LDL) across endothelial cells and how NF-κB and PPAR-γ were involved in this process. TNF-α significantly increased the transcytosis of LDL across human umbilical vein endothelial cells (HUVECs) and stimulated an increase of subendothelial retention of LDL in vascular walls. These effects of TNF-α were substantially blocked not only by transcytosis inhibitors, but also by NF-κB inhibitors and PPAR-γ inhibitors. In ApoE(-/-) mice, both NF-κB and PPAR-γ inhibitors alleviated the early atherosclerotic changes promoted by TNF-α. NF-κB and PPAR-γ inhibitors down-regulated the transcriptional activities of NF-κB and PPAR-γ induced by TNF-α. Furthermore, cross-binding activity assay revealed that NF-κB and PPAR-γ could form an active transcription factor complex containing both the NF-κB P65 subunit and PPAR-γ. The increased expressions of LDL transcytosis-related proteins (LDL receptor and caveolin-1, -2) stimulated by TNF-α were also blocked by both NF-κB inhibitors and PPAR-γ inhibitors. TNF-α promotes atherosclerosis by increasing the LDL transcytosis across endothelial cells and thereby facilitating LDL retention in vascular walls. In this process, NF-κB and PPAR-γ are activated coordinately to up-regulate the expression of transcytosis-related proteins. These observations suggest that inhibitors of either NF-κB or PPAR-γ can be used to target atherosclerosis. PMID:24594319

  13. PAF-degrading acetylhydrolase is preferentially associated with dense LDL and VHDL-1 in human plasma. Catalytic characteristics and relation to the monocyte-derived enzyme.

    PubMed

    Tselepis, A D; Dentan, C; Karabina, S A; Chapman, M J; Ninio, E

    1995-10-01

    In human plasma, platelet activating factor (PAF)-degrading acetylhydrolase (acetylhydrolase) is principally transported in association with LDLs and HDLs; this enzyme hydrolyzes PAF and short-chain forms of oxidized phosphatidylcholine, transforming them into lyso-PAF and lysophosphatidylcholine, respectively. We have examined the distribution, catalytic characteristics, and transfer of acetylhydrolase activity among plasma lipoprotein subspecies separated by isopycnic density gradient ultracentrifugation; the possibility that the plasma enzyme may be partially derived from adherent monocytes has also been evaluated. In normolipidemic subjects with Lp(a) levels < 0.1 mg/mL, acetylhydrolase was associated preferentially with small, dense LDL particles (LDL-5; d = 1.050 to 1.063 g/mL) and with the very-high-density lipoprotein-1 subfraction (VHDL-1; d = 1.156 to 1.179 g/mL), representing 23.9 +/- 1.7% and 20.6 +/- 3.2%, respectively, of total plasma activity. The apparent Km values for PAF of the enzyme associated with such lipoproteins were 89.7 +/- 23.4 and 34.8 +/- 4.5 mumol/L for LDL-5 and VHDL-1, respectively: indeed, the Km value for LDL-5 was some 10-fold higher than that of the light LDL-1, LDL-2, and LDL-3 subspecies, whereas the Km of VHDL-1 was some twofold greater than those of the HDL-2 and HDL-3 subspecies. Furthermore, when expressed on the basis of unit plasma volume, the Vmax of the acetylhydrolase associated with LDL-5 was some 150-fold greater than that in LDL-1 (d = 1.019 to 1.023 g/mL). No significant differences in the pH dependence of enzyme activity or in sensitivity to protease inactivation, sulfydryl reagents, the serine protease inhibitor Pefabloc, or the PAF antagonist CV 3988 could be detected between apo B-containing and apo A-I-containing lipoprotein particle subspecies. Incubation of LDL-1 (Km = 8.4 +/- 2.6 mumol/L) and LDL-2 (d = 1.023 to 1.029 g/mL; Km = 8.4 +/- 3.3 mumol/L) subspecies with LDL-5, in which acetylhydrolase had been

  14. Phthalocyanine-labeled LDL for tumor imaging and photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Li, Hui; Marotta, Diane; Kim, Soungkyoo; Chance, Britton; Glickson, Jerry D.; Busch, Theresa M.; Zheng, Gang

    2005-01-01

    Current limitation of both near-infrared (NIR) tumor imaging and photodynamic therapy (PDT) is their lack of sufficient tumor-to-tissue contrast due to the relatively non-specific nature of delivering dye to the tumor, which has led to false negatives for NIR imaging and inadequate therapeutic ratio for PDT. Hence, agents targeting "cancer signatures", i.e. molecules that accumulate selectively in cancer cells, are particular attractive. One of these signatures is low-density-lipoprotein receptor (LDLR), which is overexpressed in many tumors. We have developed pyropheophorbide cholesterol oleate reconstituted LDL as a LDLR-targeting photosensitizer (PS) and demonstrated its LDLR-mediated uptake in vitro and in vivo. To improve the labeling efficiency for achieving high probe/protein ratio, tetra-t-butyl silicon phthalocyanine bearing two oleate moieties at its axial positions, (tBu)4SiPcBOA, was designed and synthesized. This compound was designed to 1) prevent the PS aggregation; 2) improve the PS solubility in non-polar solvent; and 3) maximize the PS binding to LDL phospholipid monolayer. Using this novel strategy, (tBu)4SiPcBOA was reconstituted into LDL (r-SiPcBOA-LDL) with a very high payload (500:1 molar ratio). In addition, (tBu)4SiPcBOA reconstituted acetylated LDL (r-SiPcBOA)-AcLDL with similar payload was also prepared. Since Ac-LDL cannot bind to LDLR, (r-SiPcBOA)-AcLDL can serve as the negative control to evaluate LDLR targeting specificity. For biological evaluation of these new agents, confocal microscopy and in vitro PDT protocols were performed using LDLR-overexpressing human hepatoblastoma G2 (HepG2) tumor model. These studies suggest that LDL serves as a delivery vehicle to bring large amount of the NIR/PDT agents selectively to tumor cells overexpressing LDLR.

  15. A Single In-Vial Dual Extraction Strategy for the Simultaneous Lipidomics and Proteomics Analysis of HDL and LDL Fractions.

    PubMed

    Godzien, Joanna; Ciborowski, Michal; Armitage, Emily Grace; Jorge, Inmaculada; Camafeita, Emilio; Burillo, Elena; Martín-Ventura, Jose Luis; Rupérez, Francisco J; Vázquez, Jesús; Barbas, Coral

    2016-06-01

    A single in-vial dual extraction (IVDE) procedure for the subsequent analysis of lipids and proteins in the high-density lipoprotein (HDL) and low-density lipoprotein (LDL) fractions derived from the same biological sample is presented. On the basis of methyl-tert-butyl ether (MTBE) extraction, IVDE leads to the formation of three phases: a protein pellet at the bottom, an aqueous phase with polar compounds, and an ether phase with lipophilic compounds. After sample extraction, performed within a high-performance liquid chromatography vial insert, the ether phase was directly injected for lipid fingerprinting, while the protein pellet, after evaporation of the remaining sample, was used for proteomics analysis. Human HDL and LDL isolates were used to test the suitability of the IVDE methodology for lipid and protein analysis from a single sample in terms of data quality and matching composition to that of HDL and LDL. Subsequently, HDL and LDL fractions isolated from ApoE-KO and wild-type mice were used to validate the capacity of IVDE for revealing changes in lipid and protein abundance. Results indicate that IVDE can be successfully used for the subsequent analysis of lipids and proteins with the advantages of time saving, simplicity, and reduced sample amount. PMID:27117984

  16. Argan Oil Exerts an Antiatherogenic Effect by Improving Lipids and Susceptibility of LDL to Oxidation in Type 2 Diabetes Patients

    PubMed Central

    Ould Mohamedou, M. M.; Zouirech, K.; El Messal, M.; El Kebbaj, M. S.; Chraibi, A.; Adlouni, A.

    2011-01-01

    In this study, we investigate the effect of argan oil consumption on serum lipids, apolipoproteins (AI and B), CRP, and LDL susceptibility to oxidation in type 2 diabetic patients which are known to have a high level of cardiovascular risk due to lipid abnormalities and lipid peroxidation. For that, 86 type 2 diabetic patients with dyslipidemia were randomized to one group consuming 25 mL/day of argan oil during 3 weeks and control group consuming 20 g/day of butter in breakfast. After argan oil intervention, serum triglycerides decreased by 11.84%, (P = 0.001), total chol by 9.13%, (P = 0.01), and LDL-chol by 11.81%, (P = 0.02). However, HDL-chol and Apo AI increased (10.51%, P = 0.01 and 9.40%,  P = 0.045, resp.). Susceptibility of LDL to lipid peroxidation was significantly reduced by increasing of 20.95%, (P = 0.038) in lag phase after argan oil consumption. In conclusion, we show for the first time that consumption of argan oil may have an antiatherogenic effect by improving lipids, and the susceptibility of LDL to oxidation in type 2 diabetes patients with dyslipidemia, and can therefore be recommended in the nutritional management of type 2 diabetes. PMID:22114593

  17. Argan Oil Exerts an Antiatherogenic Effect by Improving Lipids and Susceptibility of LDL to Oxidation in Type 2 Diabetes Patients.

    PubMed

    Ould Mohamedou, M M; Zouirech, K; El Messal, M; El Kebbaj, M S; Chraibi, A; Adlouni, A

    2011-01-01

    In this study, we investigate the effect of argan oil consumption on serum lipids, apolipoproteins (AI and B), CRP, and LDL susceptibility to oxidation in type 2 diabetic patients which are known to have a high level of cardiovascular risk due to lipid abnormalities and lipid peroxidation. For that, 86 type 2 diabetic patients with dyslipidemia were randomized to one group consuming 25 mL/day of argan oil during 3 weeks and control group consuming 20 g/day of butter in breakfast. After argan oil intervention, serum triglycerides decreased by 11.84%, (P = 0.001), total chol by 9.13%, (P = 0.01), and LDL-chol by 11.81%, (P = 0.02). However, HDL-chol and Apo AI increased (10.51%, P = 0.01 and 9.40%,  P = 0.045, resp.). Susceptibility of LDL to lipid peroxidation was significantly reduced by increasing of 20.95%, (P = 0.038) in lag phase after argan oil consumption. In conclusion, we show for the first time that consumption of argan oil may have an antiatherogenic effect by improving lipids, and the susceptibility of LDL to oxidation in type 2 diabetes patients with dyslipidemia, and can therefore be recommended in the nutritional management of type 2 diabetes. PMID:22114593

  18. Gender disparity in LDL-induced cardiovascular damage and the protective role of estrogens against electronegative LDL

    PubMed Central

    2014-01-01

    Background Increased levels of the most electronegative type of LDL, L5, have been observed in the plasma of patients with metabolic syndrome (MetS) and ST-segment elevation myocardial infarction and can induce endothelial dysfunction. Because men have a higher predisposition to developing coronary artery disease than do premenopausal women, we hypothesized that LDL electronegativity is increased in men and promotes endothelial damage. Methods L5 levels were compared between middle-aged men and age-matched, premenopausal women with or without MetS. We further studied the effects of gender-influenced LDL electronegativity on aortic cellular senescence and DNA damage in leptin receptor–deficient (db/db) mice by using senescence-associated–β-galactosidase and γH2AX staining, respectively. We also studied the protective effects of 17β-estradiol and genistein against electronegative LDL–induced senescence in cultured bovine aortic endothelial cells (BAECs). Results L5 levels were higher in MetS patients than in healthy subjects (P < 0.001), particularly in men (P = 0.001). LDL isolated from male db/db mice was more electronegative than that from male or female wild-type mice. In addition, LDL from male db/db mice contained abundantly more apolipoprotein CIII and induced more BAEC senescence than did female db/db or wild-type LDL. In the aortas of db/db mice but not wild-type mice, we observed cellular senescence and DNA damage, and the effect was more significant in male than in female db/db mice. Pretreatment with 17β-estradiol or genistein inhibited BAEC senescence induced by male or female db/db LDL and downregulated the expression of lectin-like oxidized LDL receptor-1 and tumor necrosis factor-alpha protein. Conclusion The gender dichotomy of LDL-induced cardiovascular damage may underlie the increased propensity to coronary artery disease in men. PMID:24666525

  19. Apolipoprotein B100

    MedlinePlus

    ... DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 47. Robinson JG. What is the role of advanced lipoprotein analysis in practice? J Am Coll Cardiol. Dec 2012; ...

  20. Apolipoprotein B100

    MedlinePlus

    ... 2011:chap 47. Robinson JG. What is the role of advanced lipoprotein analysis in practice? J Am Coll Cardiol. Dec 2012;60(25):2607-2615. Semenkovich, CF. Disorders of lipid metabolism. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  1. LDL biochemical modifications: a link between atherosclerosis and aging

    PubMed Central

    Alique, Matilde; Luna, Carlos; Carracedo, Julia; Ramírez, Rafael

    2015-01-01

    Atherosclerosis is an aging disease in which increasing age is a risk factor. Modified low-density lipoprotein (LDL) is a well-known risk marker for cardiovascular disease. High-plasma LDL concentrations and modifications, such as oxidation, glycosylation, carbamylation and glycoxidation, have been shown to be proatherogenic experimentally in vitro and in vivo. Atherosclerosis results from alterations to LDL in the arterial wall by reactive oxygen species (ROS). Evidence suggests that common risk factors for atherosclerosis raise the likelihood that free ROS are produced from endothelial cells and other cells. Furthermore, oxidative stress is an important factor in the induction of endothelial senescence. Thus, endothelial damage and cellular senescence are well-established markers for atherosclerosis. This review examines LDL modifications and discusses the mechanisms of the pathology of atherosclerosis due to aging, including endothelial damage and oxidative stress, and the link between aging and atherosclerosis. PMID:26637360

  2. Mechanisms and genetic determinants regulating sterol absorption, circulating LDL levels, and sterol elimination: implications for classification and disease risk

    PubMed Central

    Calandra, Sebastiano; Tarugi, Patrizia; Speedy, Helen E.; Dean, Andrew F.; Bertolini, Stefano; Shoulders, Carol C.

    2011-01-01

    This review integrates historical biochemical and modern genetic findings that underpin our understanding of the low-density lipoprotein (LDL) dyslipidemias that bear on human disease. These range from life-threatening conditions of infancy through severe coronary heart disease of young adulthood, to indolent disorders of middle- and old-age. We particularly focus on the biological aspects of those gene mutations and variants that impact on sterol absorption and hepatobiliary excretion via specific membrane transporter systems (NPC1L1, ABCG5/8); the incorporation of dietary sterols (MTP) and of de novo synthesized lipids (HMGCR, TRIB1) into apoB-containing lipoproteins (APOB) and their release into the circulation (ANGPTL3, SARA2, SORT1); and receptor-mediated uptake of LDL and of intestinal and hepatic-derived lipoprotein remnants (LDLR, APOB, APOE, LDLRAP1, PCSK9, IDOL). The insights gained from integrating the wealth of genetic data with biological processes have important implications for the classification of clinical and presymptomatic diagnoses of traditional LDL dyslipidemias, sitosterolemia, and newly emerging phenotypes, as well as their management through both nutritional and pharmaceutical means. PMID:21862702

  3. Mechanisms and genetic determinants regulating sterol absorption, circulating LDL levels, and sterol elimination: implications for classification and disease risk.

    PubMed

    Calandra, Sebastiano; Tarugi, Patrizia; Speedy, Helen E; Dean, Andrew F; Bertolini, Stefano; Shoulders, Carol C

    2011-11-01

    This review integrates historical biochemical and modern genetic findings that underpin our understanding of the low-density lipoprotein (LDL) dyslipidemias that bear on human disease. These range from life-threatening conditions of infancy through severe coronary heart disease of young adulthood, to indolent disorders of middle- and old-age. We particularly focus on the biological aspects of those gene mutations and variants that impact on sterol absorption and hepatobiliary excretion via specific membrane transporter systems (NPC1L1, ABCG5/8); the incorporation of dietary sterols (MTP) and of de novo synthesized lipids (HMGCR, TRIB1) into apoB-containing lipoproteins (APOB) and their release into the circulation (ANGPTL3, SARA2, SORT1); and receptor-mediated uptake of LDL and of intestinal and hepatic-derived lipoprotein remnants (LDLR, APOB, APOE, LDLRAP1, PCSK9, IDOL). The insights gained from integrating the wealth of genetic data with biological processes have important implications for the classification of clinical and presymptomatic diagnoses of traditional LDL dyslipidemias, sitosterolemia, and newly emerging phenotypes, as well as their management through both nutritional and pharmaceutical means. PMID:21862702

  4. Mipomersen, an antisense oligonucleotide to apolipoprotein B-100, reduces lipoprotein(a) in various populations with hypercholesterolemia: Results of 4 Phase III Trials

    PubMed Central

    Santos, Raul D.; Raal, MD Frederick J.; Catapano, Alberico L.; Witztum, Joseph L; Steinhagen-Thiessen, Elisabeth; Tsimikas, Sotirios

    2015-01-01

    Objective Lp(a) is an independent, causal, genetic risk factor for cardiovascular disease and aortic stenosis. Current pharmacologic lipid-lowering therapies do not optimally lower Lp(a), particularly in patients with familial hypercholesterolemia (FH). Approach and Results In four Phase III trials, 382 patients on maximally tolerated lipid-lowering therapy were randomized 2:1 to weekly subcutaneous mipomersen 200 mg (n=256) or placebo (n=126) for 26 weeks. Populations included homozygous FH (HoFH), heterozygous FH (HeFH) with concomitant coronary artery disease (CAD), severe hypercholesterolemia (HC), and HC at high risk for CAD. Lp(a) was measured eight times between baseline and week 28 inclusive. Of the 382 patients, 57% and 44% had baseline Lp(a) levels >30 mg/dL and >50 mg/dL, respectively. In the pooled analysis, the mean percent decrease (median, interquartile range, IQR) in Lp(a) at 28 weeks was significantly greater in the mipomersen group compared with placebo (-26.4 (-42.8, 5.4) vs. -0.0 (10.7, 15.3), p<0.001). In the mipomersen group in patients with Lp(a) levels >30 mg/dL or >50 mg/dL, attainment of Lp(a) values ≤30 mg/dL or ≤50 mg/dL was most frequent in HoFH and severe HC patients. In the combined groups, modest correlations were present between percent change in apoB and Lp(a) (r=0.43, p<0.001) and LDL-C and Lp(a) (r=0.36, p<0.001) plasma levels. Conclusions Mipomersen consistently and effectively reduced Lp(a) levels in patients with a variety of lipid abnormalities and cardiovascular risk. Modest correlations were present between apoB and Lp(a) lowering but the mechanistic relevance mediating Lp(a) reduction is currently unknown. PMID:25614280

  5. LDL-Cholesterol: Standards of Treatment 2016: A German Perspective.

    PubMed

    März, Winfried; Scharnagl, Hubert; Gouni-Berthold, Ioanna; Silbernagel, Günther; Dressel, Alexander; Grammer, Tanja B; Landmesser, Ulf; Dieplinger, Hans; Windler, Eberhard; Laufs, Ulrich

    2016-10-01

    Decreasing low-density lipoprotein cholesterol (LDL-C) is one of the few established and proven principles for the prevention and treatment of atherosclerosis. The higher the individual cardiovascular risk, the higher the benefit of lipid-lowering pharmacotherapy. Therefore, treatment options are chosen based on a patient's total cardiovascular risk. The latter depends not only on the levels of LDL-C but also on the presence of cardiovascular disease (CVD) and on the number and severity of other risk factors. Current guidelines recommend the lowering of LDL-C to 115 mg/dl (3 mmol/l) in patients with low and moderate risk. The LDL-C treatment target is <100 mg/dl (2.6 mmol/l) for patients at high risk and <70 mg/dl (1.8 mmol/l) for patients at very high risk. Although lifestyle measures remain a fundamental part of treatment, many patients require drug therapy to achieve their LDL-C targets. Statins are the drugs of choice, with other options including ezetimibe and the newly available monoclonal antibodies against PCSK9 (proprotein convertase subtilisin/kexin type 9). In some cases, bile acid-binding sequestrants and fibrates can also be considered. Nicotinic acid is no longer available in Germany. PCSK9 antibodies decrease LDL-C about 50-60 % and are well tolerated. Their effects on clinical endpoints are being investigated in large randomized trials. The aim of the present review is to summarize the current guidelines and treatment options for hypercholesterolemia. Moreover, we provide an appraisal of PCSK9 antibodies and propose their use in selected patient populations, particularly in those at very high cardiovascular risk whose LDL-C levels under maximally tolerated lipid-lowering therapy are significantly over their treatment target. PMID:27430233

  6. Genome-wide association study of genetic determinants of LDL-c response to atorvastatin therapy: importance of Lp(a) [S

    PubMed Central

    Deshmukh, Harshal A.; Colhoun, Helen M.; Johnson, Toby; McKeigue, Paul M.; Betteridge, D. John; Durrington, Paul N.; Fuller, John H.; Livingstone, Shona; Charlton-Menys, Valentine; Neil, Andrew; Poulter, Neil; Sever, Peter; Shields, Denis C.; Stanton, Alice V.; Chatterjee, Aurobindo; Hyde, Craig; Calle, Roberto A.; DeMicco, David A.; Trompet, Stella; Postmus, Iris; Ford, Ian; Jukema, J. Wouter; Caulfield, Mark; Hitman, Graham A.

    2012-01-01

    We carried out a genome-wide association study (GWAS) of LDL-c response to statin using data from participants in the Collaborative Atorvastatin Diabetes Study (CARDS; n = 1,156), the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT; n = 895), and the observational phase of ASCOT (n = 651), all of whom were prescribed atorvastatin 10 mg. Following genome-wide imputation, we combined data from the three studies in a meta-analysis. We found associations of LDL-c response to atorvastatin that reached genome-wide significance at rs10455872 (P = 6.13 × 10−9) within the LPA gene and at two single nucleotide polymorphisms (SNP) within the APOE region (rs445925; P = 2.22 × 10−16 and rs4420638; P = 1.01 × 10−11) that are proxies for the ϵ2 and ϵ4 variants, respectively, in APOE. The novel association with the LPA SNP was replicated in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) trial (P = 0.009). Using CARDS data, we further showed that atorvastatin therapy did not alter lipoprotein(a) [Lp(a)] and that Lp(a) levels accounted for all of the associations of SNPs in the LPA gene and the apparent LDL-c response levels. However, statin therapy had a similar effect in reducing cardiovascular disease (CVD) in patients in the top quartile for serum Lp(a) levels (HR = 0.60) compared with those in the lower three quartiles (HR = 0.66; P = 0.8 for interaction). The data emphasize that high Lp(a) levels affect the measurement of LDL-c and the clinical estimation of LDL-c response. Therefore, an apparently lower LDL-c response to statin therapy may indicate a need for measurement of Lp(a). However, statin therapy seems beneficial even in those with high Lp(a). PMID:22368281

  7. Genome-wide association study of genetic determinants of LDL-c response to atorvastatin therapy: importance of Lp(a).

    PubMed

    Deshmukh, Harshal A; Colhoun, Helen M; Johnson, Toby; McKeigue, Paul M; Betteridge, D John; Durrington, Paul N; Fuller, John H; Livingstone, Shona; Charlton-Menys, Valentine; Neil, Andrew; Poulter, Neil; Sever, Peter; Shields, Denis C; Stanton, Alice V; Chatterjee, Aurobindo; Hyde, Craig; Calle, Roberto A; Demicco, David A; Trompet, Stella; Postmus, Iris; Ford, Ian; Jukema, J Wouter; Caulfield, Mark; Hitman, Graham A

    2012-05-01

    We carried out a genome-wide association study (GWAS) of LDL-c response to statin using data from participants in the Collaborative Atorvastatin Diabetes Study (CARDS; n = 1,156), the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT; n = 895), and the observational phase of ASCOT (n = 651), all of whom were prescribed atorvastatin 10 mg. Following genome-wide imputation, we combined data from the three studies in a meta-analysis. We found associations of LDL-c response to atorvastatin that reached genome-wide significance at rs10455872 (P = 6.13 × 10(-9)) within the LPA gene and at two single nucleotide polymorphisms (SNP) within the APOE region (rs445925; P = 2.22 × 10(-16) and rs4420638; P = 1.01 × 10(-11)) that are proxies for the ε2 and ε4 variants, respectively, in APOE. The novel association with the LPA SNP was replicated in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) trial (P = 0.009). Using CARDS data, we further showed that atorvastatin therapy did not alter lipoprotein(a) [Lp(a)] and that Lp(a) levels accounted for all of the associations of SNPs in the LPA gene and the apparent LDL-c response levels. However, statin therapy had a similar effect in reducing cardiovascular disease (CVD) in patients in the top quartile for serum Lp(a) levels (HR = 0.60) compared with those in the lower three quartiles (HR = 0.66; P = 0.8 for interaction). The data emphasize that high Lp(a) levels affect the measurement of LDL-c and the clinical estimation of LDL-c response. Therefore, an apparently lower LDL-c response to statin therapy may indicate a need for measurement of Lp(a). However, statin therapy seems beneficial even in those with high Lp(a). PMID:22368281

  8. The Dresden Apheresis Center - experience with LDL apheresis and immunoadsorption.

    PubMed

    Julius, Ulrich; Tselmin, Sergey; Fischer, Sabine; Passauer, Jens; Bornstein, Stefan R

    2009-12-29

    The first apheresis center in former German Democratic Republic was established in Dresden November 1990 following the reunification of Germany. We here summarize the activities of this center to date. From the center's establishment until the end of July 2009 13,291 sessions of therapeutic apheresis have been performed. Four LDL apheresis methods, namely DALI, Therasorb LDL, HELP and lipidfiltration, are available and several comparative studies of these methods have been published. In addition, we have established the Therasorb IG method and two rheophoresis methods (Rheofilter SR 20; TheraSorb-Rheo Adsorber). Currently we treat 53 high-risk patients with LDL apheresis, including 6 post- heart transplant patients and 5 patients with immunoadsorption. Since November 1990 we have seen a marked reduction in the number of new cardiovascular events by apheresis intervention, but they could not be totally prevented and 2 patients died despite LDL apheresis treatment. In our clinical experience all 4 LDL apheresis methods appear equally effective. However, it is an advantage to have the ability to switch methods in patients in whom one method was less effective or less well tolerated. We also successfully treated patients suffering from Evans' syndrome, pemphigus, urticaria vasculitis with monoclonal gammopathy IgM Type Kappa, lichen myxoedematosus or lupus erythematodes with immunoadsorption. The rheophoresis approach has been used in patients with age-dependent degeneration of the macula, sudden hearing loss, leg ulcers, and diabetic foot syndrome. PMID:20129367

  9. Polymorphic DNA haplotypes at the LDL receptor locus.

    PubMed Central

    Leitersdorf, E; Chakravarti, A; Hobbs, H H

    1989-01-01

    Mutations in the low-density lipoprotein (LDL) receptor gene result in the autosomal dominant disorder familial hypercholesterolemia (FH). Many different LDL receptor mutations have been identified and characterized, demonstrating a high degree of allelic heterogeneity at this locus. The ability to identify mutant LDL receptor genes for prenatal diagnosis of homozygous FH or to study the role of the LDL receptor gene in polygenic hypercholesterolemia requires the use of closely linked RFLPs. In the present study we used 10 different RFLPs, including three newly described polymorphisms, to construct 123 independent haplotypes from 20 Caucasian American pedigrees. Our sample contained 31 different haplotypes varying in frequency from 0.8% to 29.3%; the five most common haplotypes account for 67.5% of the sample. The heterozygosity and PIC of each site were determined, and these values disclosed that eight of the RFLPs were substantially polymorphic. Linkage-disequilibrium analysis of the haplotype data revealed strong nonrandom associations among all 10 RFLPs, especially among those sites clustered in the 3' region of the gene. Evolutionary analysis suggests the occurrence of both mutational and recombinational events in the generation of the observed haplotypes. A strategy for haplotype analysis of the LDL receptor gene in individuals of Caucasian American descent is presented. Images Figure 2 Figure 3 PMID:2563635

  10. Complement profile and activation mechanisms by different LDL apheresis systems.

    PubMed

    Hovland, Anders; Hardersen, Randolf; Nielsen, Erik Waage; Enebakk, Terje; Christiansen, Dorte; Ludviksen, Judith Krey; Mollnes, Tom Eirik; Lappegård, Knut Tore

    2012-07-01

    Extracorporeal removal of low-density lipoprotein (LDL) cholesterol by means of selective LDL apheresis is indicated in otherwise uncontrolled familial hypercholesterolemia. During blood-biomaterial interaction other constituents than the LDL particles are affected, including the complement system. We set up an ex vivo model in which human whole blood was passed through an LDL apheresis system with one of three different apheresis columns: whole blood adsorption, plasma adsorption and plasma filtration. The concentrations of complement activation products revealed distinctly different patterns of activation and adsorption by the different systems. Evaluated as the final common terminal complement complex (TCC) the whole blood system was inert, in contrast to the plasma systems, which generated substantial and equal amounts of TCC. Initial classical pathway activation was revealed equally for both plasma systems as increases in the C1rs-C1inh complex and C4d. Alternative pathway activation (Bb) was most pronounced for the plasma adsorption system. Although the anaphylatoxins (C3a and C5a) were equally generated by the two plasma separation systems, they were efficiently adsorbed to the plasma adsorption column before the "outlet", whereas they were left free in the plasma in the filtration system. Consequently, during blood-biomaterial interaction in LDL apheresis the complement system is modulated in different manners depending on the device composition. PMID:22373816

  11. OxLDL or TLR2-induced cytokine response is enhanced by oxLDL-independent novel domain on mouse CD35

    Technology Transfer Automated Retrieval System (TEKTRAN)

    OxLDL binding to CD36 is shown to result in macrophage activation and foam cell formation that have been implicated in atherosclerosis. However, CD36 has also been shown to induce inflammatory response to other ligands besides oxLDL. During the course of blocking CD36 oxLDL binding function using an...

  12. Inhibiting LDL glycation ameliorates increased cholesteryl ester synthesis in macrophages and hypercholesterolemia and aortic lipid peroxidation in streptozotocin diabetic rats

    PubMed Central

    Cohen, Margo P.; Shea, Elizabeth A.; Wu, Van-Yu

    2009-01-01

    Increased nonenzymatic glycation of apoB-containing lipoproteins impairs uptake and metabolism by the high affinity low density lipoprotein (LDL) receptor, and is one of the post-secretory modifications contributory to accelerated atherosclerosis in diabetes. The present study evaluated in vitro and in vivo effects of 2,2-chlorophenylaminophenylacetate (CAP22) to probe the influence of glycated lipoprotein on cholesterol homeostasis. This compound prevented the increased formation of glycated products in LDL incubated with 200 mM glucose and the increased cholesteryl ester synthesis in THP-1 macrophages induced by apoB-containing lipoproteins preincubated with high glucose concentration. The elevated circulating concentrations of glycated lipoprotein and cholesterol and higher vascular levels of lipid peroxidation products observed in streptozotocin diabetic rats compared to nondiabetic controls were significantly reduced in diabetic animals treated for six months with test compound. These results are the first to demonstrate that inhibiting nonenzymatic glycation of apoB-containing lipoproteins ameliorates abnormalities contributory to hypercholesterolemia and atherogenic risk in diabetes. PMID:19922964

  13. Boron tracedrug design for neutron dynamic therapeutics for LDL.

    PubMed

    Hori, Hitoshi; Nazumi, Yoshijiro; Uto, Yoshihiro

    2013-01-01

    We describe our solution for removal of the low-density lipoprotein (LDL) depot contained in proteins and lipids as a 'druggable' target for atherosclerotic cardiovascular diseases by neutron dynamic therapy (NDT), which we developed using boron tracedrugs for NDT against bovine serum albumin as a model protein. Thus, we examined, among our developed boron tracedrugs, a boron-containing curcuminoid derivative UTX-51, to destroy freshly isolated human LDL dynamically under irradiated thermal neutron to obtain a decreased intensity of band of LDL treated with UTX-51 and thermal neutron irradiation in their SDS-PAGE and electrophoresis analysis. These results suggest that UTX-51 might be a novel candidate of 'beyond chemical' therapeutic agents for atherosclerotic cardiovascular disease. PMID:23852519

  14. Intradomain Confinement of Disulfides in the Folding of Two Consecutive Modules of the LDL Receptor

    PubMed Central

    Martínez-Oliván, Juan; Fraga, Hugo; Arias-Moreno, Xabier; Ventura, Salvador; Sancho, Javier

    2015-01-01

    The LDL receptor internalizes circulating LDL and VLDL particles for degradation. Its extracellular binding domain contains ten (seven LA and three EGF) cysteine-rich modules, each bearing three disulfide bonds. Despite the enormous number of disulfide combinations possible, LDLR oxidative folding leads to a single native species with 30 unique intradomain disulfides. Previous folding studies of the LDLR have shown that non native disulfides are initially formed that lead to compact species. Accordingly, the folding of the LDLR has been described as a "coordinated nonvectorial” reaction, and it has been proposed that early compaction funnels the reaction toward the native structure. Here we analyze the oxidative folding of LA4 and LA5, the modules critical for ApoE binding, isolated and in the LA45 tandem. Compared to LA5, LA4 folding is slow and inefficient, resembling that of LA5 disease-linked mutants. Without Ca++, it leads to a mixture of many two-disulfide scrambled species and, with Ca++, to the native form plus two three-disulfide intermediates. The folding of the LA45 tandem seems to recapitulate that of the individual repeats. Importantly, although the folding of the LA45 tandem takes place through formation of scrambled isomers, no interdomain disulfides are detected, i.e. the two adjacent modules fold independently without the assistance of interdomain covalent interactions. Reduction of incredibly large disulfide combinatorial spaces, such as that in the LDLR, by intradomain confinement of disulfide bond formation might be also essential for the efficient folding of other homologous disulfide-rich receptors. PMID:26168158

  15. Myeloperoxidase modulation by LDL apheresis in Familial Hypercholesterolemia

    PubMed Central

    2011-01-01

    Background Myeloperoxidase (MPO) is a marker of plaque vulnerability and a mechanistic bridge between inflammation and cardiovascular disease, and thus is a suitable target for therapeutic strategy against cardiovascular disease. Methods Since hypercholesterolemia is associated with atherosclerosis and inflammation, we tested whether MPO serum levels were up-regulated in Familial Hypercholesterolemia (FH) and whether acute reduction of total cholesterol (TC) would also reduce MPO concentration. FH subjects undergoing LDL-apheresis (LDL-A) treatment are a paradigmatic clinical model where TC rapidly plunges from extremely high to extremely low levels after selective LDL removal, and then spontaneously rebounds to baseline conditions. This clinical setting allows multiple intra-patient observations at different plasma TC concentrations. We measured MPO levels in serum by ELISA tests, and in peripheral leukocytes by immunofluorescence, to learn whether they were affected by the changes in TC levels. Serum MPO was measured before and serially up to the 14th day following LDL-A. Results In both serum and peripheral leukocytes, MPO concentrations were i) higher than in sex- and age-matched healthy controls (p < 0.01); ii) decreased with TC reduction; iii) parallel with TC time course; iv) correlated with plasma TC. At regression analysis, plasma TC was the only variable considered that influenced MPO serum levels (β 0.022 ± 0.010, p < 0.0001). Conclusions In FH the MPO serum levels were modulated through changes in the TC concentrations carried out by LDL-A. Further study is needed to determine whether reduced MPO levels obtained by LDL-A could have any therapeutic impact. PMID:22014237

  16. Cathepsin G activity lowers plasma LDL and reduces atherosclerosis

    PubMed Central

    Wang, Jing; Sjöberg, Sara; Tang, Ting-Ting; Öörni, Katariina; Wu, Wenxue; Liu, Conglin; Secco, Blandine; Tia, Viviane; Sukhova, Galina K.; Fernandes, Cleverson; Lesner, Adam; Kovanen, Petri T.; Libby, Peter; Cheng, Xiang; Shi, Guo-Ping

    2014-01-01

    Cathepsin G (CatG), a serine protease present in mast cells and neutrophils, can produce angiotensin-II (Ang-II) and degrade elastin. Here we demonstrate increased CatG expression in smooth muscle cells (SMCs), endothelial cells (ECs), macrophages, and T cells from human atherosclerotic lesions. In low-density lipoprotein (LDL) receptor-deficient (Ldlr−/−) mice, the absence of CatG reduces arterial wall elastin degradation and attenuates early atherosclerosis when mice consume a Western diet for 3 months. When mice consume this diet for 6 months, however, CatG deficiency exacerbates atherosclerosis in aortic arch without affecting lesion inflammatory cell content or extracellular matrix accumulation, but raises plasma total cholesterol and LDL levels without affecting high-density lipoprotein (HDL) or triglyceride levels. Patients with atherosclerosis also have significantly reduced plasma CatG levels that correlate inversely with total cholesterol (r= −0.535, P<0.0001) and LDL cholesterol (r= −0.559, P<0.0001), but not with HDL cholesterol (P=0.901) or triglycerides (P=0.186). Such inverse correlations with total cholesterol (r= −0.504, P<0.0001) and LDL cholesterol (r= −0.502, P<0.0001) remain significant after adjusting for lipid lowering treatments among this patient population. Human CatG degrades purified human LDL, but not HDL. This study suggests that CatG promotes early atherogenesis through its elastinolytic activity, but suppresses late progression of atherosclerosis by degrading LDL without affecting HDL or triglycerides. PMID:25092171

  17. Oxidized LDL Immune Complexes and Oxidized LDL Differentially Affect the Expression of Genes Involved with Inflammation and Survival In Human U937 Monocytic Cells

    PubMed Central

    Hammad, Samar M; Twal, Waleed O; Barth, Jeremy L; Smith, Kent J.; Saad, Antonio F; Virella, Gabriel; Argraves, W. Scott; Lopes-Virella., Maria F

    2008-01-01

    Objective To compare the global effects of oxidized LDL (oxLDL) and oxLDL-containing immune complexes (oxLDL-IC) on gene expression in human monocytic cells and to identify differentially expressed genes involved with inflammation and survival. Methods and Results U937 cells were treated with oxLDL-IC, oxLDL, Keyhole limpet hemocyanin immune complexes (KLH-IC), or vehicle for 4 h. Transcriptome profiling was performed using DNA microarrays. oxLDL-IC uniquely affected the expression of genes involved with pro-survival (RAD54B, RUFY3, SNRPB2, and ZBTB24). oxLDL-IC also regulated many genes in a manner similar to KLH-IC. Functional categorization of these genes revealed that 39% are involved with stress responses, including the unfolded protein response which impacts cell survival, 19% with regulation of transcription, 10% with endocytosis and intracellular transport of protein and lipid, and 16% with inflammatory responses including regulation of I-κB/NF-κB cascade and cytokine activity. One gene in particular, HSP70 6, greatly up-regulated by ox-LDL-IC, was found to be required for the process by which oxLDL-IC augments IL1-β secretion. The study also revealed genes uniquely up-regulated by oxLDL including genes involved with growth inhibition (OKL38, NEK3, and FTH1), oxidoreductase activity (SPXN1 and HMOX1), and transport of amino acids and fatty acids (SLC7A11 and ADFP). Conclusions These findings highlight early transcriptional responses elicited by oxLDL-IC that may underlie its cytoprotective and pro-inflammatory effects. Cross-linking of Fcγ receptors appears to be the trigger for most of the transcriptional responses to oxLDL-IC. The findings further strengthen the hypothesis that oxLDL and oxLDL-IC elicit disparate inflammatory responses and play distinct roles in the process of atherosclerosis. PMID:18597759

  18. Effects of phospholipase A2 and its products on structural stability of human LDL: relevance to formation of LDL-derived lipid droplets[S

    PubMed Central

    Jayaraman, Shobini; Gantz, Donald L.; Gursky, Olga

    2011-01-01

    Hydrolysis and oxidation of LDL stimulate LDL entrapment in the arterial wall and promote inflammation and atherosclerosis via various mechanisms including lipoprotein fusion and lipid droplet formation. To determine the effects of FFA on these transitions, we hydrolyzed LDL by phospholipase A2 (PLA2), removed FFA by albumin, and analyzed structural stability of the modified lipoproteins. Earlier, we showed that heating induces LDL remodeling, rupture, and coalescence into lipid droplets resembling those found in atherosclerotic lesions. Here, we report how FFA affect these transitions. Circular dichroism showed that mild LDL lipolysis induces partial β-sheet unfolding in apolipoprotein B. Electron microscopy, turbidity, and differential scanning calorimetry showed that mild lipolysis promotes LDL coalescence into lipid droplets. FFA removal by albumin restores LDL stability but not the protein conformation. Consequently, FFA enhance LDL coalescence into lipid droplets. Similar effects of FFA were observed in minimally oxidized LDL, in LDL enriched with exogenous FFA, and in HDL and VLDL. Our results imply that FFA promote lipoprotein coalescence into lipid droplets and explain why LDL oxidation enhances such coalescence in vivo but hampers it in vitro. Such lipid droplet formation potentially contributes to the pro-atherogenic effects of FFA. PMID:21220788

  19. Performance and Emissions Characteristics of Bio-Diesel (B100)-Ignited Methane and Propane Combustion in a Four Cylinder Turbocharged Compression Ignition Engine

    DOE PAGESBeta

    Shoemaker, N. T.; Gibson, C. M.; Polk, A. C.; Krishnan, S. R.; Srinivasan, K. K.

    2011-10-05

    Different combustion strategies and fuel sources are needed to deal with increasing fuel efficiency demands and emission restrictions. One possible strategy is dual fueling using readily available resources. Propane and natural gas are readily available with the current infrastructure and biodiesel is growing in popularity as a renewable fuel. This paper presents experimental results from dual fuel combustion of methane (as a surrogate for natural gas) and propane as primary fuels with biodiesel pilots in a 1.9 liter, turbocharged, 4 cylinder diesel engine at 1800 rev/min. Experiments were performed with different percentage energy substitutions (PES) of propane and methane andmore » at different brake mean effective pressures (BMEP/bmep). Brake thermal efficiency (BTE) and emissions (NOx, HC, CO, CO2, O2 and smoke) were also measured. Maximum PES levels for B100-methane dual fuelling were limited to 70% at 2.5 bar bmep and 48% at 10 bar bmep, and corresponding values for B100-propane dual fuelling were 64% and 43%, respectively. Maximum PES was limited by misfire at 2.5 bar bmep and the onset of engine knock at 10 bar bmep. Dual fuel BTEs approached straight B100 values at 10 bar bmep while they were significantly lower than B100 values at 2.5 bar bmep. In general dual fuelling was beneficial in reducing NOx and smoke emissions by 33% and 50%, respectively from baseline B100 levels; however, both CO and THC emissions were significantly higher than baseline B100 levels at all PES and loads.« less

  20. Performance and Emissions Characteristics of Bio-Diesel (B100)-Ignited Methane and Propane Combustion in a Four Cylinder Turbocharged Compression Ignition Engine

    SciTech Connect

    Shoemaker, N. T.; Gibson, C. M.; Polk, A. C.; Krishnan, S. R.; Srinivasan, K. K.

    2011-10-05

    Different combustion strategies and fuel sources are needed to deal with increasing fuel efficiency demands and emission restrictions. One possible strategy is dual fueling using readily available resources. Propane and natural gas are readily available with the current infrastructure and biodiesel is growing in popularity as a renewable fuel. This paper presents experimental results from dual fuel combustion of methane (as a surrogate for natural gas) and propane as primary fuels with biodiesel pilots in a 1.9 liter, turbocharged, 4 cylinder diesel engine at 1800 rev/min. Experiments were performed with different percentage energy substitutions (PES) of propane and methane and at different brake mean effective pressures (BMEP/bmep). Brake thermal efficiency (BTE) and emissions (NOx, HC, CO, CO2, O2 and smoke) were also measured. Maximum PES levels for B100-methane dual fuelling were limited to 70% at 2.5 bar bmep and 48% at 10 bar bmep, and corresponding values for B100-propane dual fuelling were 64% and 43%, respectively. Maximum PES was limited by misfire at 2.5 bar bmep and the onset of engine knock at 10 bar bmep. Dual fuel BTEs approached straight B100 values at 10 bar bmep while they were significantly lower than B100 values at 2.5 bar bmep. In general dual fuelling was beneficial in reducing NOx and smoke emissions by 33% and 50%, respectively from baseline B100 levels; however, both CO and THC emissions were significantly higher than baseline B100 levels at all PES and loads.

  1. Lectin-like Oxidized Low-Density Lipoprotein (LDL) Receptor (LOX-1): A Chameleon Receptor for Oxidized LDL.

    PubMed

    Zeya, Bushra; Arjuman, Albina; Chandra, Nimai Chand

    2016-08-16

    LOX-1, one of the main receptors for oxLDL, is found mainly on the surface of endothelial cells. It is a multifacet 52 kDa type II transmembrane protein that structurally belongs to the C-type lectin family. It exists with short intracellular N-terminal and long extracellular C-terminal hydrophilic domains separated by a hydrophobic domain of 26 amino acids. LOX-1 acts like a bifunctional receptor either showing pro-atherogenicity by activating the NFκB-mediated down signaling cascade for gene activation of pro-inflammatory molecules or playing an atheroprotective agent by receptor-mediated uptake of oxLDL in the presence of an anti-inflammatory molecule like IL-10. Mildly, moderately, and highly oxidized LDL show their characteristic features upon LOX-1 activation and its ligand binding indenture. The polymorphic LOX-1 genes are intensively associated with increased susceptibility to myocardial diseases. The splicing variant LOX IN dimerizes with the native form of LOX-1 and protects cells from damage by oxidized LDL. In the developing field of regenerating medicine, LOX-1 is a potential target for therapeutic intervention. PMID:27419271

  2. Lipopolysaccharide augments the uptake of oxidized LDL by up-regulating lectin-like oxidized LDL receptor-1 in macrophages.

    PubMed

    Hossain, Ekhtear; Ota, Akinobu; Karnan, Sivasundaram; Takahashi, Miyuki; Mannan, Shahnewaj B; Konishi, Hiroyuki; Hosokawa, Yoshitaka

    2015-02-01

    There is a growing body of evidence supporting an intimate association of immune activation with the pathogenesis of cardiovascular diseases, including atherosclerosis. Uptake of oxidized low-density lipoprotein (oxLDL) through scavenging receptors promotes the formation of mature lipid-laden macrophages, which subsequently leads to exacerbation of regional inflammation and atherosclerotic plaque formation. In this study, we first examined changes in the mRNA level of the lectin-like oxLDL receptor-1 (LOX-1) in the mouse macrophage cell line RAW264.7 and the human PMA-induced macrophage cell line THP-1 after LPS stimulation. LPS significantly up-regulated LOX-1 mRNA in RAW264.7 cells; LOX-1 cell-surface protein expression was also increased. Flow cytometry and fluorescence microscopy analyses showed that cellular uptake of fluorescence (Dil)-labeled oxLDL was significantly augmented with LPS stimulation. The augmented uptake of Dil-oxLDL was almost completely abrogated by treatment with an anti-LOX-1 antibody. Of note, knockdown of Erk1/2 resulted in a significant reduction of LPS-induced LOX-1 up-regulation. Treatment with U0126, a specific inhibitor of MEK, significantly suppressed LPS-induced expression of LOX-1 at both the mRNA and protein levels. Furthermore, LOX-1 promoter activity was significantly augmented by LPS stimulation; this augmentation was prevented by U0126 treatment. Similar results were also observed in human PMA-induced THP-1 macrophages. Taken together, our results indicate that LPS up-regulates LOX-1, at least in part through activation of the Erk1/2 signaling pathway, followed by augmented cellular oxLDL uptake, thus highlighting a critical role of TLR4-mediated aberrant LOX-1 signaling in the pathogenesis of atherosclerosis. PMID:25348362

  3. Glutathione preconditioning attenuates Ac-LDL-induced macrophage apoptosis via protein kinase C-dependent Ac-LDL trafficking.

    PubMed

    Rosenson-Schloss, Rene S; Chnari, Evangelia; Brieva, Thomas A; Dang, Anh; Moghe, Prabhas V

    2005-01-01

    Oxidized low-density lipoprotein (ox-LDL) incorporation into intimally resident vascular cells via scavenger receptors marks one of the early steps in atherosclerosis. Cellular apoptotic damage results from two major serial intracellular events: the binding and scavenger receptor-mediated uptake of oxidizable lipoproteins and the intracellular oxidative responses of accumulated lipoproteins. Most molecular approaches to prevent apoptotic damage have focused on singular events within the cascade of lipoprotein trafficking. To identify a multifocal strategy against LDL-induced apoptosis, we evaluated the role of cellular preconditioning by glutathione-ethyl ester (GSH-Et), a native redox regulator, in the prevention of the uptake and apoptotic effects of an oxidizable scavenger receptor-specific ligand, acetylated low-density lipoprotein (Ac-LDL). Our results indicate that GSH-Et-mediated protein kinase C (PKC) pathway modulation regulates Ac-LDL binding and incorporation into GSH-Et preconditioned cells and subsequently delays reactive oxygen intermediate generation and apoptotic conversion. The GSH-Et protective effects on apoptosis and Ac-LDL binding were reversed by calphostin C, a PKC inhibitor, and were accompanied by an increase in PKC phosphorylation. However, the rate of reactive oxygen intermediate accumulation was not increased following calphostin C treatment, suggesting that GSH-Et may play an important nonreactive oxygen-intermediate-based protective role in regulating apoptotic dynamics. Overall, we report on the novel role for GSH-Et preconditioning as a molecular strategy to limit lipoprotein entry into the cells, which presents a proactive modality to prevent cellular apoptosis in contrast with the prevalent antioxidant approaches that treat damage retroactively. PMID:15618124

  4. LDL electronegativity index: a potential novel index for predicting cardiovascular disease

    PubMed Central

    Ivanova, Ekaterina A; Bobryshev, Yuri V; Orekhov, Alexander N

    2015-01-01

    High cardiovascular risk conditions are frequently associated with altered plasma lipoprotein profile, such as elevated low-density lipoprotein (LDL) and LDL cholesterol and decreased high-density lipoprotein. There is, however, accumulating evidence that specific subclasses of LDL may play an important role in cardiovascular disease development, and their relative concentration can be regarded as a more relevant risk factor. LDL particles undergo multiple modifications in plasma that can lead to the increase of their negative charge. The resulting electronegative LDL [LDL(–)] subfraction has been demonstrated to be especially atherogenic, and became a subject of numerous recent studies. In this review, we discuss the physicochemical properties of LDL(–), methods of its detection, atherogenic activity, and relevance of the LDL electronegativity index as a potential independent predictor of cardiovascular risk. PMID:26357481

  5. Description of a large family with autosomal dominant hypercholesterolemia associated with the APOE p.Leu167del mutation

    PubMed Central

    Marduel, Marie; Ouguerram, Khadija; Serre, Valérie; Bonnefont-Rousselot, Dominique; Marques-Pinheiro, Alice; Berge, Knut Erik; Devillers, Martine; Luc, Gérald; Lecerf, Jean-Michel; Tosolini, Laurent; Erlich, Danièle; Peloso, Gina M.; Stitziel, Nathan; Nitchké, Patrick; Jaïs, Jean-Philippe; Abifadel, Marianne; Kathiresan, Sekar; Leren, Trond Paul; Rabès, Jean-Pierre; Boileau, Catherine; Varret, Mathilde

    2013-01-01

    Apo E mutants are associated with type III hyperlipoproteinemia characterized by high cholesterol and triglycerides levels. Autosomal Dominant Hypercholesterolemia (ADH), due to mutations in the LDLR, APOB or PCSK9 genes, is characterized by an isolated elevation of cholesterol due to high levels of low-density lipoproteins (LDL). We now report an exceptionally large family including 14 members with ADH. Through genome wide mapping, analysis of regional/functional candidate genes and whole exome sequencing, we identified a mutation in the APOE gene, p.Leu167del previously reported associated with sea-blue histiocytosis and familial combined hyperlipidemia. We confirmed the involvement of the APOE p.Leu167del in ADH, with (1) a predicted destabilization of an alpha-helix in the binding domain; (2) a decreased apo E level in LDL; and (3) a decreased catabolism of LDL. Our results show that mutations in the APOE gene can be associated with bona fide ADH. PMID:22949395

  6. Smallest LDL particles are most strongly related to coronarydisease progression in men

    SciTech Connect

    Williams, Paul T.; Superko, H. Robert; Haskell, William L.; Alderman, Edwin L.; Blanche, Patricia J.; Holl, Laura Glines; Krauss,Ronald M.

    2002-12-03

    Objective-LDLs include particle subclasses that havedifferent mobilities on polyacrylamide gradient gels: LDL-I (27.2to 28.5nm), LDL-IIa (26.5 to 27.2 nm), LDL-IIb (25.6 to 26.5 nm), LDL-IIIa (24.7to 25.6 nm), LDL-IIIb (24.2 to 24.7nm), LDL-IVa (23.3 to 24.2 nm), andLDL-IVb (22.0 to 23.3 nm in diameter). We hypothesized that theassociationbetween smaller LDL particles and coronary artery disease(CAD) risk might involve specific LDL subclasses.Methods andResults-Average 4-year onstudy lipoprotein measurements were comparedwith annualized rates of stenosischange from baseline to 4 years in 117men with CAD. The percentages of total LDL and HDL occurringwithinindividual subclasses were measured by gradient gelelectrophoresis. Annual rate of stenosis change was relatedconcordantlyto onstudy averages of total cholesterol (P 0.04), triglycerides (P0.05), VLDL mass (P 0.03),total/HDL cholesterol ratio (P 0.04), LDL-IVb(P 0.01), and HDL3a (P 0.02) and inversely to HDL2-mass (P 0.02)and HDL2b(P 0.03). The average annual rate in stenosis change was 6-fold morerapid in the fourth quartile ofLDL-IVb (5.2 percent) than in the firstquartile ( 2.5 percent, P 0.03). Stepwise multiple regression analysisshowed thatLDL-IVb was the single best predictor of stenosischange.Conclusions-LDL-IVb was the single best lipoprotein predictor ofincreased stenosis, an unexpected result, given thatLDL-IVb representsonly a minor fraction of total LDL. (Arterioscler Thromb Vasc Biol.2003;23:314-321.)

  7. Optimization of apolipoprotein-B-100 sequence coverage by liquid chromatography-tandem mass spectrometry for the future study of its posttranslational modifications.

    PubMed

    Delporte, Cédric; Van Antwerpen, Pierre; Zouaoui Boudjeltia, Karim; Noyon, Caroline; Abts, Frédéric; Métral, Frédéric; Vanhamme, Luc; Reyé, Florence; Rousseau, Alexandre; Vanhaeverbeek, Michel; Ducobu, Jean; Nève, Jean

    2011-04-01

    Proteomic applications have been increasingly used to study posttranslational modifications of proteins (PTMs). For the purpose of identifying and localizing specific but unknown PTMs on huge proteins, improving their sequence coverage is fundamental. Using liquid chromatography coupled to mass spectrometry (LC-MS/MS), peptide mapping of the native apolipoprotein-B-100 was performed to further document the effects of oxidation. Apolipoprotein-B-100 is the main protein of low-density lipoprotein particles and its oxidation could play a role in atherogenesis. Because it is one of the largest human proteins, the sequence recovery rate of apolipoprotein-B-100 only reached 1% when conventional analysis parameters were used. The different steps of the peptide mapping process-from protein treatment to data analysis-were therefore reappraised and optimized. These optimizations allowed a protein sequence recovery rate of 79%, a rate which has never been achieved previously for such a large human protein. The key points for improving peptide mapping were optimization of the data analysis software; peptide separation by LC; sample preparation; and MS acquisition. The new protocol has allowed us to increase by a factor of 4 the detection of modified peptides in apolipoprotein-B-100. This approach could easily be transferred to any study of PTMs using LC-MS/MS. PMID:21129357

  8. Proteolysis sensitizes LDL particles to phospholipolysis by secretory phospholipase A2 group V and secretory sphingomyelinase

    PubMed Central

    Plihtari, Riia; Hurt-Camejo, Eva; Öörni, Katariina; Kovanen, Petri T.

    2010-01-01

    LDL particles that enter the arterial intima become exposed to proteolytic and lipolytic modifications. The extracellular hydrolases potentially involved in LDL modification include proteolytic enzymes, such as chymase, cathepsin S, and plasmin, and phospholipolytic enzymes, such as secretory phospholipases A2 (sPLA2-IIa and sPLA2-V) and secretory acid sphingomyelinase (sSMase). Here, LDL was first proteolyzed and then subjected to lipolysis, after which the effects of combined proteolysis and lipolysis on LDL fusion and on binding to human aortic proteoglycans (PG) were studied. Chymase and cathepsin S led to more extensive proteolysis and release of peptide fragments from LDL than did plasmin. sPLA2-IIa was not able to hydrolyze unmodified LDL, and even preproteolysis of LDL particles failed to enhance lipolysis by this enzyme. However, preproteolysis with chymase and cathepsin S accelerated lipolysis by sPLA2-V and sSMase, which resulted in enhanced fusion and proteoglycan binding of the preproteolyzed LDL particles. Taken together, the results revealed that proteolysis sensitizes the LDL particles to hydrolysis by sPLA2-V and sSMase. By promoting fusion and binding of LDL to human aortic proteoglycans, the combination of proteolysis and phospholipolysis of LDL particles potentially enhances extracellular accumulation of LDL-derived lipids during atherogenesis. PMID:20124257

  9. Immunization with malondialdehyde-modified low-density lipoprotein (LDL) reduces atherosclerosis in LDL receptor-deficient mice challenged with Porphyromonas gingivalis.

    PubMed

    Turunen, S Pauliina; Kummu, Outi; Wang, Chunguang; Harila, Kirsi; Mattila, Riikka; Sahlman, Marjo; Pussinen, Pirkko J; Hörkkö, Sohvi

    2015-05-01

    Periodontal infections increase the risk of atherosclerotic vascular disease via partly unresolved mechanisms. Of the natural IgM Abs that recognize molecular mimicry on bacterial epitopes and modified lipid and protein structures, IgM directed against oxidized low-density lipoprotein (LDL) is associated with atheroprotective properties. Here, the effect of natural immune responses to malondialdehyde-modified LDL (MDA-LDL) in conferring protection against atherosclerosis, which was accelerated by the major periodontopathogen Porphyromonas gingivalis, was investigated. LDL receptor-deficient (LDLR(-/-)) mice were immunized with mouse MDA-LDL without adjuvant before topical application challenge with live P. gingivalis. Atherosclerosis was analyzed after a high-fat diet, and plasma IgG and IgM Ab levels were measured throughout the study, and the secretion of IL-5, IL-10 and IFN-γ in splenocytes stimulated with MDA-LDL was determined. LDLR(-/-) mice immunized with MDA-LDL had elevated IgM and IgG levels to MDA-LDL compared with saline-treated controls. MDA-LDL immunization diminished aortic lipid depositions after challenge with P. gingivalis compared with mice receiving only P. gingivalis challenge. Immunization of LDLR(-/-) mice with homologous MDA-LDL stimulated the production of IL-5, implicating general activation of B-1 cells. Immune responses to MDA-LDL protected from the P. gingivalis-accelerated atherosclerosis. Thus, the linkage between bacterial infectious burden and atherogenesis is suggested to be modulated via natural IgM directed against cross-reactive epitopes on bacteria and modified LDL. PMID:25134521

  10. Uptake and Trafficking of Mildly Oxidized LDL and Acetylated LDL in THP-1 Cells Does Not Explain the Differences in Lysosomal Metabolism of These Two Lipoproteins

    NASA Astrophysics Data System (ADS)

    Yancey, Patricia G.; Miles, Stacia; Schwegel, Jennifer; Gray Jerome, W.

    2002-04-01

    Foam cells in the atherosclerotic lesion have substantial cholesterol stores within large, swollen lysosomes. This feature is mimicked by incubating THP-1 macrophages with mildly oxidized low density lipoprotein (LDL). Incubation of THP-1 cells with acetylated LDL produces cytoplasmic cholesteryl ester accumulation rather than lysosomal storage. The differences could be due to differences in uptake and delivery of lipoprotein to lysosomes or to lysosomal and post-lysosomal processing events. We compared uptake and lysosomal trafficking of acetylated and oxidized LDL using colloidal gold-labeled lipoproteins. Labeling did not alter cellular cholesterol accumulation. We found that uptake and delivery to lysosomes are not different for acetylated and oxidized LDL. In fact, both oxidized and acetylated LDL can be delivered to the same lysosomes. Sequential incubation with oxidized LDL followed by acetylated LDL showed that the lipid-engorged lysosomes are long-lived structures, continuously accepting newly ingested lipoprotein. Comparison of acetylated and oxidized LDL in mouse peritoneal macrophages, a cell which does not accumulate substantial lysosomal lipid, also revealed no differences in uptake. This indicates that in THP-1 cells, the differences in metabolism of oxidized and acetylated LDL are due to cell-specific lysosomal or post-lysosomal events not present in B6C3F1 mouse macrophages.

  11. Increased LDL susceptibility to oxidation accelerates future carotid artery atherosclerosis

    PubMed Central

    2012-01-01

    Background We analyzed the causal relationship between LDL susceptibility to oxidation and the development of new carotid artery atherosclerosis over a period of 5 years. We previously described the determinants related to a risk of cardiovascular changes determined in a Japanese population participating in the Niigata Study, which is an ongoing epidemiological investigation of the prevention of cardiovascular diseases. Methods We selected 394 individuals (169 males and 225 females) who underwent a second carotid artery ultrasonographic examination in 2001 - 2002 for the present study. The susceptibility of LDL to oxidation was determined as the photometric absorbance and electrophoretic mobility of samples that had been collected in 1996 - 1997. The measurements were compared with ultrasonographic findings obtained in 2001 - 2002. Results The multivariate-adjusted model showed that age (odds ratio (OR), 1.034; 95% confidence interval (95%CI), 1.010 - 1.059), HbA1c (OR, 1.477; 95%CI, 0.980 - 2.225), and photometric O/N (OR, 2.012; 95%CI, 1.000 - 4.051) were significant variables that could independently predict the risk of new carotid artery atherosclerosis. Conclusion The susceptibility of LDL to oxidation was a significant parameter that could predict new carotid artery atherosclerosis over a 5-year period, and higher susceptibility was associated with a higher incidence of new carotid artery atherosclerosis. PMID:22230558

  12. BMP4 is increased in the aortas of diabetic ApoE knockout mice and enhances uptake of oxidized low density lipoprotein into peritoneal macrophages

    PubMed Central

    2013-01-01

    Background BMP4, a member of the transforming growth factor-beta superfamily, is upregulated in the aortas of diabetic db/db mice. However, little is known about its role in diabetic atherosclerosis. Therefore, we examined the roles of BMP4 in the formation of diabetic atherosclerosis in apolipoprotein E knockout (ApoE KO) mice and in the uptake of oxidized low density lipoprotein (oxLDL) in peritoneal macrophages of wild-type mice. Methods To induce diabetes, ApoE KO mice were intraperitoneally injected with streptozotocin. Diabetic and non-diabetic ApoE KO mice were then fed a high-fat diet for 4 weeks. Next, to investigate a role of BMP4 in the peritoneal macrophages, we examined the uptake of oxLDL in BMP4-treated macrophages. Results Diabetic ApoE KO mice showed accelerated progression of aortic plaques accompanied by increased luminal plaque area. Western blot analysis showed that BMP4 expression in the whole aorta was greatly increased in diabetic ApoE KO mice, than non-diabetic mice. Western blot analysis showed that the BMP4/SMAD1/5/8 signaling pathway was strongly activated in the aorta from diabetic ApoE KO mice, compared with control ApoE KO mice. Double immunofluorescence staining showed that BMP4 was expressed in MOMA2-labeled macrophage in the aortic lesions of ApoE KO mice. BMP4 significantly increased the uptake of oxLDL into peritoneal macrophages in vitro. Conclusion We show that in the aorta of diabetic ApoE KO mice, BMP4 is increased and activates SMAD1/5/8. Our in vitro findings indicate that BMP4 enhances oxLDL uptake in mouse peritoneal macrophages, suggesting BMP4 may be involved in aortic plaque formation in diabetic ApoE KO mice. Targeting BMP4 may offer a new strategy for inhibition of plaque progression and stabilization of atherosclerotic lesions. PMID:24107300

  13. VNN1 promotes atherosclerosis progression in apoE-/- mice fed a high-fat/high-cholesterol diet.

    PubMed

    Hu, Yan-Wei; Wu, Shao-Guo; Zhao, Jing-Jing; Ma, Xin; Lu, Jing-Bo; Xiu, Jian-Cheng; Zhang, Yuan; Huang, Chuan; Qiu, Yu-Rong; Sha, Yan-Hua; Gao, Ji-Juan; Wang, Yan-Chao; Li, Shu-Fen; Zhao, Jia-Yi; Zheng, Lei; Wang, Qian

    2016-08-01

    Accumulated evidence shows that vanin-1 (VNN1) plays a key part in glucose metabolism. We explored the effect of VNN1 on cholesterol metabolism, inflammation, apoptosis in vitro, and progression of atherosclerotic plaques in apoE(-/-) mice. Oxidized LDL (Ox-LDL) significantly induced VNN1 expression through an ERK1/2/cyclooxygenase-2/PPARα signaling pathway. VNN1 significantly increased cellular cholesterol content and decreased apoAI and HDL-cholesterol (HDL-C)-mediated efflux by 25.16% and 23.13%, respectively, in THP-1 macrophage-derived foam cells (P < 0.05). In addition, VNN1 attenuated Ox-LDL-induced apoptosis through upregulation of expression of p53 by 59.15% and downregulation of expression of B-cell lymphoma-2 127.13% in THP-1 macrophage (P < 0.05). In vivo, apoE(-/-) mice were divided randomly into two groups and transduced with lentivirus (LV)-Mock or LV-VNN1 for 12 weeks. VNN1-treated mice showed increased liver lipid content and plasma levels of TG (124.48%), LDL-cholesterol (119.64%), TNF-α (148.74%), interleukin (IL)-1β (131.81%), and IL-6 (156.51%), whereas plasma levels of HDL-C (25.75%) were decreased significantly (P < 0.05). Consistent with these data, development of atherosclerotic lesions was increased significantly upon infection of apoE(-/-) mice with LV-VNN1. These observations suggest that VNN1 may be a promising therapeutic candidate against atherosclerosis. PMID:27281478

  14. Clinical- and cost-effectiveness of LDL particle-guided statin therapy: a simulation study.

    PubMed

    Folse, Henry J; Goswami, Devesh; Rengarajan, Badri; Budoff, Matthew; Kahn, Richard

    2014-09-01

    We used the Archimedes Model, a mathematical simulation model (Model) to estimate the clinical- and cost-effectiveness of using LDL particle concentration (LDL-P) as an adjunct or alternative to LDL cholesterol (LDL-C) to guide statin therapy. LDL-P by NMR has been shown to be a better measure of cardiovascular disease (CVD) risk than LDL-C, and may therefore be a better gauge of the need for and response to statin treatment. Using the Model, we conducted a virtual clinical trial comparing the use of LDL-C alone, LDL-P alone, and LDL-C and LDL-P together to guide treatment in the general adult population, and in high-risk, dyslipidemic subpopulations. In the general population, the 5-year major adverse cardiovascular event (MACE) relative risk reduction (RRR) of LDL-P alone compared to the control arm (LDL-C alone) was 5.0% (95% CI, 4.7-5.3; p < .0001); using both LDL-C and LDL-P (dual markers) led to 3.0% RRR compared to the control arm (95% CI, 2.8-3.3; p < .0001). For individuals with diabetes, the RRR was 7.3% (95% CI, 6.4-8.2; p < .0001) for LDL-P alone and 6.9% for dual markers (95% CI, 6.1-7.8; both, p < .0001). In the general population, the costs per quality-adjusted life year (QALY) associated with the use of LDL-P alone were $76,052 at 5 years and $8913 at 20 years and $142,825 at 5 years and $25,505 at 20 years with the use of both markers. In high-risk subpopulations, the use of LDL-P alone was cost-saving at 5 years; whereas the cost per QALY for the use of both markers was $14,250 at 5 years and $859 at 20 years for high-risk dyslipidemics, $19,192 at 5 years and $649 at 20 years for diabetics, and $9030 at 5 years and $7268 at 20 years for patients with prior CHD. In conclusion, the model estimates that using LDL-P to guide statin therapy may reduce the risk of CVD events to a greater extent than does the use of LDL-C alone and maybe cost-effective or cost-saving for high-risk patients. PMID:25050538

  15. Autoantibodies against oxidized LDL in chronic renal failure: role of renal function, diet, and lipids.

    PubMed

    Bergesio, F; Monzani, G; Ciuti, R; Cirami, C; Martinelli, F; Salvadori, M; Tosi, P L

    2001-02-01

    Lipid peroxidation (LP) has recently been suggested to trigger the atherosclerotic process as well as to worsen the progression of renal disease. Autoantibodies against oxidized low-density lipoproteins (Ox-LDLAb) were considered to provide a sensitive marker to detect LDL oxidation in vivo. To date few studies have been reported on Ox-LDLAb levels in patients with different degrees of renal failure. The aim of this study was to evaluate the influences of renal function, dietary manipulation, and lipids on Ox-LDLAb concentrations in uremic patients either on conservative or replacement therapy. Seventy-one patients (42 males, 29 females) aged 60 +/- 19 years with chronic renal failure (CRF) of different etiology and degree were divided into four groups according to serum creatinine levels [sCr(mg/dl)] and diet: CRF I > or = 1.5-3.0, CRF II > 3.0-5.5, and CRF III > 5.5 were all patients on a conventional low-protein diet, while a fourth group included patients on a vegetarian diet supplemented with keto analogues and amino acids (CRF SD >3.0). A further group was represented by patients on dialysis therapy. All patients were examined for Ox-LDLAb, triglycerides (TG), total cholesterol, HDL and LDL cholesterol, and apolipoproteins Apo A1, Apo B, and Lp(a). The results were compared with those of 20 controls (9 males and 11 females) aged 52 +/- 11 years with sCr <1.5 mg/dl. Ox-LDLAb increased, although not significantly, with TG and Lp(a) from the early stages of CRF along with the deterioration of renal function. However, TG and Lp(a) levels were significantly higher in all groups of patients except those on vegetarian diet (CRF SD). This group also showed the lowest Ox-LDLAb levels. No relationship was observed between lipids or apolipoproteins and Ox-LDLAb. Hyperlipidemic patients did not show higher Ox-LDLAb levels than normolipidemics. Our results show a progressive increase of LP as the renal function declines, which may account for the increased risk of

  16. Impact of APOE gene polymorphisms on the lipid profile in an Algerian population

    PubMed Central

    2013-01-01

    Background The importance of apolipoprotein E (APOE) in lipid and lipoprotein metabolism is well established. However, the impact of APOE polymorphisms has never been investigated in an Algerian population. This study assessed, for the fist time, the relationships between three APOE polymorphisms (epsilon, rs439401, rs4420638) and plasma lipid concentrations in a general population sample from Algeria. Methods The association analysis was performed in the ISOR study, a representative sample of the population living in Oran (787 subjects aged between 30 and 64). Polymorphisms were considered both individually and as haplotypes. Results In the ISOR sample, APOE ϵ4 allele carriers had higher plasma triglyceride (p=0.0002), total cholesterol (p=0.009) and LDL-cholesterol (p=0.003) levels than ϵ3 allele carriers. No significant associations were detected for the rs4420638 and rs439401 SNPs. Linkage disequilibrium and haplotype analyses confirmed the respectively deleterious and protective impacts of the ϵ4 and ϵ2 alleles on LDL-cholesterol levels and showed that the G allele of the rs4420638 polymorphism may exert a protective effect on LDL-cholesterol levels in subjects bearing the APOE epsilon 4 allele. Conclusion Our results showed that (i) the APOE epsilon polymorphism has the expected impact on the plasma lipid profile and (ii) the rs4420638 G allele may counterbalance the deleterious effect of the ϵ4 allele on LDL-cholesterol levels in an Algerian population. PMID:24160669

  17. Effects of Lowering LDL Cholesterol on Progression of Kidney Disease

    PubMed Central

    Haynes, Richard; Lewis, David; Emberson, Jonathan; Reith, Christina; Agodoa, Lawrence; Cass, Alan; Craig, Jonathan C.; de Zeeuw, Dick; Feldt-Rasmussen, Bo; Fellström, Bengt; Levin, Adeera; Wheeler, David C.; Walker, Rob; Herrington, William G.; Baigent, Colin; Landray, Martin J.; Baigent, Colin; Landray, Martin J.; Reith, Christina; Emberson, Jonathan; Wheeler, David C.; Tomson, Charles; Wanner, Christoph; Krane, Vera; Cass, Alan; Craig, Jonathan; Neal, Bruce; Jiang, Lixin; Hooi, Lai Seong; Levin, Adeera; Agodoa, Lawrence; Gaziano, Mike; Kasiske, Bertram; Walker, Rob; Massy, Ziad A.; Feldt-Rasmussen, Bo; Krairittichai, Udom; Ophascharoensuk, Vuddidhej; Fellström, Bengt; Holdaas, Hallvard; Tesar, Vladimir; Wiecek, Andrzej; Grobbee, Diederick; de Zeeuw, Dick; Grönhagen-Riska, Carola; Dasgupta, Tanaji; Lewis, David; Herrington, Will; Mafham, Marion; Majoni, William; Wallendszus, Karl; Grimm, Richard; Pedersen, Terje; Tobert, Jonathan; Armitage, Jane; Baxter, Alex; Bray, Christopher; Chen, Yiping; Chen, Zhengming; Hill, Michael; Knott, Carol; Parish, Sarah; Simpson, David; Sleight, Peter; Young, Alan; Collins, Rory

    2014-01-01

    Lowering LDL cholesterol reduces the risk of developing atherosclerotic events in CKD, but the effects of such treatment on progression of kidney disease remain uncertain. Here, 6245 participants with CKD (not on dialysis) were randomly assigned to simvastatin (20 mg) plus ezetimibe (10 mg) daily or matching placebo. The main prespecified renal outcome was ESRD (defined as the initiation of maintenance dialysis or kidney transplantation). During 4.8 years of follow-up, allocation to simvastatin plus ezetimibe resulted in an average LDL cholesterol difference (SEM) of 0.96 (0.02) mmol/L compared with placebo. There was a nonsignificant 3% reduction in the incidence of ESRD (1057 [33.9%] cases with simvastatin plus ezetimibe versus 1084 [34.6%] cases with placebo; rate ratio, 0.97; 95% confidence interval [95% CI], 0.89 to 1.05; P=0.41). Similarly, allocation to simvastatin plus ezetimibe had no significant effect on the prespecified tertiary outcomes of ESRD or death (1477 [47.4%] events with treatment versus 1513 [48.3%] events with placebo; rate ratio, 0.97; 95% CI, 0.90 to 1.04; P=0.34) or ESRD or doubling of baseline creatinine (1189 [38.2%] events with treatment versus 1257 [40.2%] events with placebo; rate ratio, 0.93; 95% CI, 0.86 to 1.01; P=0.09). Exploratory analyses also showed no significant effect on the rate of change in eGFR. Lowering LDL cholesterol by 1 mmol/L did not slow kidney disease progression within 5 years in a wide range of patients with CKD. PMID:24790178

  18. OxLDL or TLR2-induced cytokine response is enhanced by oxLDL-independent novel domain on mouse CD36

    PubMed Central

    Xie, ChengHui; Ng, HangPong; Nagarajan, Shanmugam

    2011-01-01

    OxLDL binding to CD36 is shown to result in macrophage activation and foam cell formation that have been implicated in atherosclerosis. However, CD36 has also been shown to induce inflammatory response to other ligands besides oxLDL. During the course of blocking CD36 oxLDL binding function using anti CD36 antibodies, we have identified a novel domain of CD36 that triggers inflammatory response-independent of oxLDL binding. OxLDL bound to the mouse reporter cell line RAW-Blue induced TNF-α and RANTES mRNA and protein expression. Pretreatment of RAW-Blue cells with an anti-mCD36 mAb, JC63.1, an activating mCD36 mAb, surprisingly did not inhibit oxLDL-induced response. Further, binding of this antibody to CD36 alone induced a pro-inflammatory cytokine response in RAW-Blue cells as well as primary mouse macrophages. The induction of cytokine response was specific only to this antibody and was CD36-dependent, since CD36−/− macrophages failed to induce a similar response. The interaction of the antibody to CD36 led to activation of NF-κB and MAP kinase. Notably, a CD36 peptide blocked oxLDL-induced foam cell formation and macrophage activation. However, the activating mCD36 mAb induced macrophage activation was not inhibited by CD36 peptide. Further, activating mCD36 mAb enhanced oxLDL- or TLR2- or TLR4-mediated inflammatory responses. Collectively, our data provide evidence that activating mCD36 mAb binds to a domain different from the oxLDL-binding domain on mouse CD36, and suggest that interaction at this domain may contribute to oxLDL-independent macrophage inflammatory responses that lead to chronic inflammatory diseases. PMID:21281677

  19. Rice Bran Oil Decreases Total and LDL Cholesterol in Humans: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials.

    PubMed

    Jolfaie, N R; Rouhani, M H; Surkan, P J; Siassi, F; Azadbakht, L

    2016-07-01

    Cardiovascular disease (CVD) has become a concerning health problem because of its increasing prevalence. Vegetable oils such as rice bran oil may improve blood lipids, risk factors for CVD. We performed a systematic review and meta-analysis to identify and quantify the effects of rice bran oil on lipid profiles in humans. Literature databases (Pubmed, Scopus, Science Direct, Proquest, Ovid, and Google Scholar) were systematically searched until the end of November 2015, with no restrictions regarding study design, time, or language. The variables extracted for the meta-analysis included low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), total cholesterol (TC), triacylglycerol (TAG), VLDL-C, apoA, apoB, Lp(a), TC/HDL-C, and LDL-C/HDL-C. From 415 identified articles, 11 randomized controlled trials met the eligibility criteria and were included in our review. Rice bran oil consumption resulted in a significant decrease in concentrations of LDL-C (-6.91 mg/dl, 95% CI, -10.24 to -3.57; p<0.001) and TC (-12.65 mg/dl; 95% CI, -18.04 to -7.27; p<0.001). The increase in HDL-C levels were considerable only in men (6.65 mg/dl; 95% CI, 2.38-10.92; p=0.002). Results of our meta-analysis provided no evidence of a significant effekt of rice bran oil on other lipid profile components. In conclusion, consumption of rice bran oil can reduce LDL-C and TC concentrations, which may lead to prevention and control of CVD. It also has favorable effects on HDL-C concentrations in men. However, changes related to other lipid profile components are not considerable. PMID:27311126

  20. Circulating Oxidized LDL and Inflammation in Extreme Pediatric Obesity

    PubMed Central

    Norris, Anne L.; Steinberger, Julia; Steffen, Lyn M.; Metzig, Andrea M.; Schwarzenberg, Sarah Jane; Kelly, Aaron S.

    2013-01-01

    Oxidative stress and inflammation have not been well-characterized in extreme pediatric obesity. We compared levels of circulating oxidized LDL (oxLDL), C-reactive protein (CRP), and interleukin-6 (IL-6) in extremely obese (EO) children to normal weight (NW) and overweight/obese (OW/OB) children. OxLDL, CRP, IL-6, body mass index (BMI), blood pressure, and fasting glucose, insulin, and lipids were obtained in 225 children and adolescents (age 13.5 ± 2.5 years; boys 55%). Participants were classified into three groups based on gender- and age-specific BMI percentile: NW (<85th, n = 127), OW/OB (85th-<1.2 times the 95th percentile, n = 64) and EO (≥1.2 times the 95th percentile or BMI ≥35 kg/m2, n = 34). Measures were compared across groups using ANCOVA, adjusted for gender, age, and race. Blood pressure, insulin, and lipids worsened across BMI groups (all p<0.0001). OxLDL (NW: 40.8 ± 9.0 U/L, OW/OB: 45.7 ± 12.1 U/L, EO: 63.5 ± 13.8 U/L) and CRP (NW: 0.5 ± 1.0 mg/L, OW/OB: 1.4 ± 2.9 mg/L, EO: 5.6 ± 4.9 mg/L) increased significantly across BMI groups (all groups differed with p<0.01). IL-6 was significantly higher in EO (2.0 ± 0.9 pg/mL) compared to OW/OB (1.3 ± 1.2 pg/mL, p<0.001) and NW (1.1 ± 1.0 pg/mL, p<0.0001) but was not different between NW and OW/OB. Extreme pediatric obesity, compared to milder forms of adiposity and normal weight, is associated with higher levels of oxidative stress and inflammation, suggesting that markers of early cardiovascular disease and type 2 diabetes mellitus are already present in this young population. PMID:21331062

  1. Oxidative LDL modification is increased in vascular dementia and is inversely associated with cognitive performance.

    PubMed

    Li, L; Willets, R S; Polidori, M C; Stahl, W; Nelles, G; Sies, H; Griffiths, H R

    2010-03-01

    It is not known whether the association between increased plasma homocysteine (Hcy) associated with LDL modification and propensity for LDL uptake by macrophages in cardiovascular disease patients holds true in vascular dementia (VaD). Plasma from 83 subjects diagnosed with Alzheimer's disease (AD), VaD, mild cognitive impairment (MCI) and from controls was analysed to examine (1) whether LDL isolated from the plasma of VaD is biochemically and functionally distinct from that isolated from AD, MCI or controls; and (2) whether such biomarkers of LDL phenotype are related to plasma folate levels, Hcy levels and/or to disease severity. Folate and vitamin B6 levels were significantly lower in VaD subjects than in controls. VaD-LDL showed increased protein carbonyl content (p < 0.05) and was more susceptible to scavenging by macrophages (p < 0.05) than AD- or control-LDL. Patients from the VaD cohort were more prevalent in the lowest tertile for HDL:LDL and the upper tertile for LDL oxidation; the combined parameters of HDL cholesterol, LDL oxidation and scavenging by macrophages show 87% sensitivity towards VaD detection. The association between folate deficiency, LDL modification and dysfunction in VaD but not in AD may provide a novel biomarker assessment to discriminate between the diseases. PMID:20166891

  2. Cell surface expression of LDL receptor in chronic hepatitis C: correlation with viral load.

    PubMed

    Petit, Jean-Michel; Minello, Anne; Duvillard, Laurence; Jooste, Valérie; Monier, Serge; Texier, Véronique; Bour, Jean-Baptiste; Poussier, Alix; Gambert, Philippe; Verges, Bruno; Hillon, Patrick

    2007-07-01

    The LDL receptor (LDL-R) has been proposed as the viral receptor for Hepatitis C virus (HCV). This hypothesis has been based exclusively on in vitro studies. In human mononuclear cells, LDL-R gene expression has been demonstrated to be parallel and be coordinately regulated to gene expression in the human liver. The purpose of the current study was to determine the mononuclear cell surface expression of the LDL receptor in patients with HCV chronic infection according to viral load. Sixty-eight consecutive untreated chronic hepatitis C patients were studied to determine the mononuclear cell surface expression of the LDL-R. LDL-Rs were quantified at the surface of mononuclear cells in fresh blood samples taken after fasting using flow cytometry. LDL-R expression was significantly associated with LDL-cholesterol (r = -0.25; P = 0.03) and HCV-viral load (r = 0.37, P = 0.002). In multivariate analysis, the LDL-R expression was significantly associated with HCV viral load, whereas genotype, age, body mass index, and fibrosis were not. In conclusion, our data provided by a human study, suggest that the LDL-R may be one of the receptors implicated in HCV replication. PMID:17473053

  3. Effects of Simulated Heat Waves with Strong Sudden Cooling Weather on ApoE Knockout Mice.

    PubMed

    Zhang, Shuyu; Kuang, Zhengzhong; Zhang, Xiakun

    2015-06-01

    This study analyzes the mechanism of influence of heat waves with strong sudden cooling on cardiovascular diseases (CVD) in ApoE-/- mice. The process of heat waves with strong sudden cooling was simulated with a TEM1880 meteorological-environment simulation chamber according to the data obtained at 5 a.m. of 19 June 2006 to 11 p.m. of 22 June 2006. Forty-eight ApoE-/- mice were divided into six blocks based on their weight. Two mice from each block were randomly assigned to control, heat wave, temperature drop, and rewarming temperature groups. The experimental groups were transferred into the climate simulator chamber for exposure to the simulated heat wave process with strong sudden temperature drop. After 55, 59, and 75 h of exposure, the experimental groups were successively removed from the chamber to monitor physiological indicators. Blood samples were collected by decollation, and the hearts were harvested in all groups. The levels of heat stress factors (HSP60, SOD, TNF, sICAM-1, HIF-1α), cold stress factors (NE, EPI), vasoconstrictor factors (ANGII, ET-1, NO), and four items of blood lipid (TC, TG, HDL-C, and LDL-C) were measured in each ApoE-/- mouse. Results showed that the heat waves increased the levels of heat stress factors except SOD decreased, and decreased the levels of vasoconstrictor factors and blood lipid factors except TC increased. The strong sudden temperature drop in the heat wave process increased the levels of cold stress factors, vasoconstrictor factors and four blood lipid items (except the level of HDL-C which decreased) and decreased the levels of heat stress factors (except the level of SOD which increased). The analysis showed that heat waves could enhance atherosclerosis of ApoE-/- mice. The strong sudden temperature drop during the heat wave process increased the plasma concentrations of NE and ANGII, which indicates SNS activation, and resulted in increased blood pressure. NE and ANGII are vasoconstrictors involved in systemic

  4. Cytokeratin 8 in Association with sdLDL and ELISA Development

    PubMed Central

    Ashmaig, Mohmed

    2015-01-01

    Background: Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide. Cytokeratins (CKs) which may also be expressed in vascular smooth muscle cells (SMCs) are generally considered to be markers for the differentiation of epithelial cells. Small, dense, low-density lipoprotein (sdLDL) particles, also termed LDL-IV, independently predict risk of CVD. Aims: The aims of this study were to develop an analytical method, apart from ultracentrifugation capable of isolating sdLDL in order to study any associated proteins. Materials and Methods: Using modified gradient gel electrophoresis (GGE), de-identified sdLDL-enriched plasma was used to physically elute and isolate sdLDL particles. To validate the finding, additional plasma from 77 normal and 48 higher risk subjects were used to measure sdLDL particles and CK8. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting method were used to identify the characteristics of proteins associated with sdLDL. An enzyme-linked immunosorbent assay (ELISA) method was developed and validated for the measurement of CK8 in plasma. Results: The validation of the CK8 ELISA method showed good analytical performance. The isolated sdLDL particles were verified with nondenaturing GGE with the apolipoprotein B component confirmed by Western immunoblotting. Confirmed by SDS-PAGE and Western immunoblotting, CK8 was associated with sdLDL. Two-tailed statistical analysis showed that CK8 and sdLDL particles were significantly higher in the high-risk CVD group compared to control group (P < 0.01 and P < 0.01, respectively). Conclusion: This study reports a novel association between CK8 and sdLDL in individuals with CVD who have a predominance of sdLDL. PMID:26713292

  5. Ldl modified by hypochlorous acid is a potent inhibitor of lecithin-cholesterol acyltransferase activity.

    PubMed

    McCall, M R; Carr, A C; Forte, T M; Frei, B

    2001-06-01

    Modification of low density lipoprotein (LDL) by myeloperoxidase-generated HOCl has been implicated in human atherosclerosis. Incubation of LDL with HOCl generates several reactive intermediates, primarily N-chloramines, which may react with other biomolecules. In this study, we investigated the effects of HOCl-modified LDL on the activity of lecithin-cholesterol acyltransferase (LCAT), an enzyme essential for high density lipoprotein maturation and the antiatherogenic reverse cholesterol transport pathway. We exposed human LDL (0.5 mg protein/mL) to physiological concentrations of HOCl (25 to 200 micromol/L) and characterized the resulting LDL modifications to apolipoprotein B and lipids; the modified LDL was subsequently incubated with apolipoprotein B-depleted plasma (density >1.063 g/mL fraction), which contains functional LCAT. Increasing concentrations of HOCl caused various modifications to LDL, primarily, loss of lysine residues and increases in N-chloramines and electrophoretic mobility, whereas lipid hydroperoxides were only minor products. LCAT activity was extremely sensitive to HOCl-modified LDL and was reduced by 23% and 93% by LDL preincubated with 25 and 100 micromol/L HOCl, respectively. Addition of 200 micromol/L ascorbate or N-acetyl derivatives of cysteine or methionine completely prevented LCAT inactivation by LDL preincubated with LDL, which inhibits lipid hydroperoxide-mediated inactivation of LCAT, failed to prevent the loss of enzyme activity. Our data indicate that N-chloramines from HOCl-modified LDL mediate the loss of plasma LCAT activity and provide a novel mechanism by which myeloperoxidase-generated HOCl may promote atherogenesis. PMID:11397717

  6. Decorin and biglycan retain LDL in disease-prone valvular and aortic subendothelial intimal matrix

    PubMed Central

    Neufeld, Edward B.; Zadrozny, Leah M.; Phillips, Darci; Aponte, Angel; Yu, Zu-Xi; Balaban, Robert S.

    2014-01-01

    Objective Subendothelial LDL retention by intimal matrix proteoglycans is an initial step in atherosclerosis and calcific aortic valve disease. Herein, we identify decorin and biglycan as the proteoglycans that preferentially retain LDL in intimal matrix at disease-prone sites in normal valve and vessel wall. Methods The porcine aortic valve and renal artery ostial diverter, initiation sites of calcific valve disease and renal atherosclerosis, respectively, from normal non-diseased animals were used as models in these studies. Results Fluorescent human LDL was selectively retained on the lesion-prone collagen/proteoglycan-enriched aortic surface of the valve, where the elastic lamina is depleted, as previously observed in lesion-prone sites in the renal ostium. iTRAQ mass spectrometry of valve and diverter protein extracts identified decorin and biglycan as the major subendothelial intimal matrix proteoglycans electrostatically retained on human LDL affinity columns. Decorin levels correlated with LDL binding in lesion-prone sites in both tissues. Collagen binding to LDL was shown to be proteoglycan-mediated. All known basement membrane proteoglycans bound LDL suggesting they may modulate LDL uptake into the subendothelial matrix. The association of purified decorin with human LDL in an in vitro microassay was blocked by serum albumin and heparin suggesting anti-atherogenic roles for these proteins in vivo. Conclusions LDL electrostatic interactions with decorin and biglycan in the valve leaflets and vascular wall is a major source of LDL retention. The complementary electrostatic sites on LDL or these proteoglycans may provide a novel therapeutic target for preventing one of the earliest events in these cardiovascular diseases. PMID:24529131

  7. Sex Differences in the Impact of the Mediterranean Diet on LDL Particle Size Distribution and Oxidation

    PubMed Central

    Bédard, Alexandra; Corneau, Louise; Lamarche, Benoît; Dodin, Sylvie; Lemieux, Simone

    2015-01-01

    Sex differences have been previously highlighted in the cardioprotective effects of the Mediterranean diet (MedDiet). The objective of this study was to investigate whether sex differences also exist with regard to LDL particle size distribution and oxidation. Participants were 37 men and 32 premenopausal women (24–53 years) with slightly elevated LDL-C concentrations (3.4–4.9 mmol/L) or total cholesterol/HDL-C ≥5.0. Variables were measured before and after a four-week isoenergetic MedDiet. Sex differences were found in response to the MedDiet for the proportion of medium LDL (255–260 Å) (p for sex-by-time interaction = 0.01) and small, dense LDL (sdLDL; <255 Å) (trend; p for sex-by-time interaction = 0.06), men experiencing an increase in the proportion of medium LDL with a concomitant reduction in the proportion of sdLDL, while an opposite trend was observed in women. A sex difference was also noted for estimated cholesterol concentrations among sdLDL (p for sex-by-time interaction = 0.03), with only men experiencing a reduction in response to the MedDiet. The MedDiet marginally reduced oxidized LDL (oxLDL) concentrations (p = 0.07), with no sex difference. Results suggest that short-termconsumption of the MedDiet leads to a favorable redistribution of LDL subclasses from smaller to larger LDL only in men. These results highlight the importance of considering sex issues in cardiovascular benefits of the MedDiet. PMID:25988764

  8. Identification of candidate genes encoding an LDL-C QTL in baboons[S

    PubMed Central

    Karere, Genesio M.; Glenn, Jeremy P.; Birnbaum, Shifra; Hafizi, Sussan; Rainwater, David L.; Mahaney, Michael C.; VandeBerg, John L.; Cox, Laura A.

    2013-01-01

    Cardiovascular disease (CVD) is the leading cause of death in developed countries, and dyslipidemia is a major risk factor for CVD. We previously identified a cluster of quantitative trait loci (QTL) on baboon chromosome 11 for multiple, related quantitative traits for serum LDL-cholesterol (LDL-C). Here we report differentially regulated hepatic genes encoding an LDL-C QTL that influences LDL-C levels in baboons. We performed hepatic whole-genome expression profiling for LDL-C-discordant baboons fed a high-cholesterol, high-fat (HCHF) diet for seven weeks. We detected expression of 117 genes within the QTL 2-LOD support interval. Three genes were differentially expressed in low LDL-C responders and 8 in high LDL-C responders in response to a HCHF diet. Seven genes (ACVR1B, CALCOCO1, DGKA, ERBB3, KRT73, MYL6B, TENC1) showed discordant expression between low and high LDL-C responders. To prioritize candidate genes, we integrated miRNA and mRNA expression profiles using network tools and found that four candidates (ACVR1B, DGKA, ERBB3, TENC1) were miRNA targets and that the miRNAs were inversely expressed to the target genes. Candidate gene expression was validated using QRT-PCR and Western blotting. This study reveals candidate genes that influence variation in LDL-C in baboons and potential genetic mechanisms for further investigation. PMID:23596326

  9. Oxidized-LDL induce morphological changes and increase stiffness of endothelial cells

    SciTech Connect

    Chouinard, Julie A.; Grenier, Guillaume; Khalil, Abdelouahed; Vermette, Patrick

    2008-10-01

    There is increasing evidence suggesting that oxidized low-density lipoproteins (ox-LDL) play a critical role in endothelial injury contributing to the age-related physio-pathological process of atherosclerosis. In this study, the effects of native LDL and ox-LDL on the mechanical properties of living human umbilical vein endothelial cells (HUVEC) were investigated by atomic force microscopy (AFM) force measurements. The contribution of filamentous actin (F-actin) and vimentin on cytoskeletal network organization were also examined by fluorescence microscopy. Our results revealed that ox-LDL had an impact on the HUVEC shape by interfering with F-actin and vimentin while native LDL showed no effect. AFM colloidal force measurements on living individual HUVEC were successfully used to measure stiffness of cells exposed to native and ox-LDL. AFM results demonstrated that the cell body became significantly stiffer when cells were exposed for 24 h to ox-LDL while cells exposed for 24 h to native LDL displayed similar rigidity to that of the control cells. Young's moduli of LDL-exposed HUVEC were calculated using two models. This study thus provides quantitative evidence on biomechanical mechanisms related to endothelial cell dysfunction and may give new insight on strategies aiming to protect endothelial function in atherosclerosis.

  10. Natural phenylpropanoids protect endothelial cells against oxidized LDL-induced cytotoxicity.

    PubMed

    Martin-Nizard, Françoise; Sahpaz, Sevser; Furman, Christophe; Fruchart, Jean-Charles; Duriez, Patrick; Bailleul, François

    2003-03-01

    There is increasing evidence that oxidized low-density lipoproteins (Ox-LDL) might be involved in the pathogenesis of atherosclerosis and it has been reported that polyphenols inhibit LDL peroxidation and atherosclerosis. Minimally oxidized LDL (mOx-LDL) induce cytotoxicity in cultured bovine aortic endothelial cells (BAEC). The goal of this study was to test the protective effect of five natural polyphenols isolated from the aerial parts of Marrubium vulgare L. against mOx-LDL-induced cytotoxicity in BAEC. Four phenylpropanoid glycosides (acteoside 1, forsythoside B 2, arenarioside 3, ballotetroside 4) and one non-glycosidic derivative (caffeoyl-l-malic acid 5) were tested. These compounds inhibited both copper (Cu 2+)- and 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced in vitro LDL oxidation and preserved the morphological aspects of BAEC during their incubation with mOx-LDL. Furthermore, they reduced the accumulation of aldehydes in the cultured medium during the incubation of BAEC with mOx-LDL and prevented cellular LDH leakage during this period. These data suggest that natural phenylpropanoids inhibit mOx-LDL-induced cellular toxicity and that inhibition of lipid peroxidation could be a key mechanism in the cytoprotective effect of these molecules. PMID:12677522

  11. PLTP activity in premenopausal women. Relationship with lipoprotein lipase, HDL, LDL, body fat, and insulin resistance.

    PubMed

    Murdoch, S J; Carr, M C; Hokanson, J E; Brunzell, J D; Albers, J J

    2000-02-01

    Plasma phospholipid transfer protein (PLTP) is thought to play a major role in the facilitated transfer of phospholipids between lipoproteins and in the modulation of high density lipoprotein (HDL) particle size and composition. However, little has been reported concerning the relationships of PLTP with plasma lipoprotein parameters, lipolytic enzymes, body fat distribution, insulin, and glucose in normolipidemic individuals, particularly females. In the present study, 50 normolipidemic healthy premenopausal females were investigated. The relationships between the plasma PLTP activity and selected variables were assessed. PLTP activity was significantly and positively correlated with low density lipoprotein (LDL) cholesterol (r(s) = 0.53), apoB (r(s) = 0.44), glucose (r(s) = 0.40), HDL cholesterol (r(s) = 0.38), HDL(3) cholesterol (r(s) = 0.37), lipoprotein lipase activity (r(s) = 0.36), insulin (r(s) = 0.33), subcutaneous abdominal fat (r(s) = 0.36), intra-abdominal fat (r(s) = 0.29), and body mass index (r(s) = 0.29). HDL(2) cholesterol, triglyceride, and hepatic lipase were not significantly related to PLTP activity. As HDL(2) can be decreased by hepatic lipase and hepatic lipase is increased in obesity with increasing intra-abdominal fat, the participants were divided into sub-groups of non-obese (n = 35) and obese (n = 15) individuals and the correlation of PLTP with HDL(2) cholesterol was re-examined. In the non-obese subjects, HDL(2) cholesterol was found to be significantly and positively related to PLTP activity (r(s) = 0.44). Adjustment of the HDL(2) values for the effect of hepatic lipase activity resulted in a significant positive correlation between PLTP and HDL(2) (r(s) = 0.41), indicating that the strength of the relationship between PLTP activity and HDL(2) can be reduced by the opposing effect of hepatic lipase on HDL(2) concentrations. We conclude that PLTP-facilitated lipid transfer activity is related to HDL and LDL metabolism, as well as

  12. Different Functional and Structural Characteristics between ApoA-I and ApoA-4 in Lipid-Free and Reconstituted HDL State: ApoA-4 Showed Less Anti-Atherogenic Activity.

    PubMed

    Yoo, Jeong-Ah; Lee, Eun-Young; Park, Ji Yoon; Lee, Seung-Taek; Ham, Sihyun; Cho, Kyung-Hyun

    2015-06-01

    Apolipoprotein A-I and A-IV are protein constituents of high-density lipoproteins although their functional difference in lipoprotein metabolism is still unclear. To compare anti-atherogenic properties between apoA-I and apoA-4, we characterized both proteins in lipid-free and lipid-bound state. In lipid-free state, apoA4 showed two distinct bands, around 78 and 67 Å on native gel electrophoresis, while apoA-I showed scattered band pattern less than 71 Å. In reconstituted HDL (rHDL) state, apoA-4 showed three major bands around 101 Å and 113 Å, while apoA-I-rHDL showed almost single band around 98 Å size. Lipid-free apoA-I showed 2.9-fold higher phospholipid binding ability than apoA-4. In lipid-free state, BS3-crosslinking revealed that apoA-4 showed less multimerization tendency upto dimer, while apoA-I showed pentamerization. In rHDL state (95:1), apoA-4 was existed as dimer as like as apoA-I. With higher phospholipid content (255:1), five apoA-I and three apoA-4 were required to the bigger rHDL formation. Regardless of particle size, apoA-I-rHDL showed superior LCAT activation ability than apoA-4-rHDL. Uptake of acetylated LDL was inhibited by apoA-I in both lipid-free and lipid-bound state, while apoA-4 inhibited it only lipid-free state. ApoA-4 showed less anti-atherogenic activity with more sensitivity to glycation. In conclusion, apoA-4 showed inferior physiological functions in lipid-bound state, compared with those of apoA-I, to induce more pro-atherosclerotic properties. PMID:25997739

  13. Different Functional and Structural Characteristics between ApoA-I and ApoA-4 in Lipid-Free and Reconstituted HDL State: ApoA-4 Showed Less Anti-Atherogenic Activity

    PubMed Central

    Yoo, Jeong-Ah; Lee, Eun-Young; Park, Ji Yoon; Lee, Seung-Taek; Ham, Sihyun; Cho, Kyung-Hyun

    2015-01-01

    Apolipoprotein A-I and A-IV are protein constituents of high-density lipoproteins although their functional difference in lipoprotein metabolism is still unclear. To compare anti-atherogenic properties between apoA-I and apoA-4, we characterized both proteins in lipid-free and lipid-bound state. In lipid-free state, apoA4 showed two distinct bands, around 78 and 67 Å on native gel electrophoresis, while apoA-I showed scattered band pattern less than 71 Å. In reconstituted HDL (rHDL) state, apoA-4 showed three major bands around 101 Å and 113 Å, while apoA-I-rHDL showed almost single band around 98 Å size. Lipid-free apoA-I showed 2.9-fold higher phospholipid binding ability than apoA-4. In lipid-free state, BS3-crosslinking revealed that apoA-4 showed less multimerization tendency upto dimer, while apoA-I showed pentamerization. In rHDL state (95:1), apoA-4 was existed as dimer as like as apoA-I. With higher phospholipid content (255:1), five apoA-I and three apoA-4 were required to the bigger rHDL formation. Regardless of particle size, apoA-I-rHDL showed superior LCAT activation ability than apoA-4-rHDL. Uptake of acetylated LDL was inhibited by apoA-I in both lipid-free and lipid-bound state, while apoA-4 inhibited it only lipid-free state. ApoA-4 showed less anti-atherogenic activity with more sensitivity to glycation. In conclusion, apoA-4 showed inferior physiological functions in lipid-bound state, compared with those of apoA-I, to induce more pro-atherosclerotic properties. PMID:25997739

  14. Towards increased selectivity of drug delivery to cancer cells: development of a LDL-based nanodelivery system for hydrophobic photosensitizers

    NASA Astrophysics Data System (ADS)

    Buzova, Diana; Huntosova, Veronika; Kasak, Peter; Petrovajova, Dana; Joniova, Jaroslava; Dzurova, Lenka; Nadova, Zuzana; Sureau, Franck; Midkovsky, Pavol; Jancura, Daniel

    2012-10-01

    Low-density lipoproteins (LDL), a natural in vivo carrier of cholesterol in the vascular system, play a key role in the delivery of hydrophobic photosensitizers (pts) to tumor cells in photodynamic therapy (PDT) of cancer. To make this delivery system even more efficient, we have constructed a nano-delivery system by coating of LDL surface by polyethylene glycol (PEG) and dextran. Fluorescence spectroscopy and confocal fluorescence imaging were used to characterize redistribution of hypericin (Hyp), a natural potent pts, loaded in LDL/PEG and LDL/dextran complexes to free LDL molecules as well as to monitor cellular uptake of Hyp by U87-MG cells. It was shown than the redistribution process of Hyp between LDL molecules is significantly suppressed by dextran coating of LDL surface. On the other hand, PEG does not significantly influence this process. The modification of LDL molecules by the polymers does not inhibit their recognition by cellular LDL receptors. U-87 MG cellular uptake of Hyp loaded in LDL/PEG and LDL/dextran complexes appears to be similar to that one observed for Hyp transported by unmodified LDL particles. It is proposed that by polymers modified LDL molecules could be used as a basis for construction of a drug transport system for targeted delivery of hydrophobic drugs to cancer cells expressing high level of LDL receptors.

  15. Oxidized low density lipoprotein (LDL) and platelet intracellular calcium: interaction with nitric oxide.

    PubMed

    Zuliani, V; Tommasol, R; Gaino, S; Degan, M; Cominacini, L; Davoli, A; Lechi, C; Lechi, A; Minuz, P

    1998-01-01

    The present study tested the effects of ox-low density lipoprotein (LDL) on nitric oxide (NO)-dependent decrease in agonist-stimulated [Ca2+]i. The effects of ox-LDL on platelet aggregation were also evaluated. Platelets loaded with FURA 2 AM (2 micromol/litre) were incubated with NO-donors for 2-10 min to obtain a 40-50% reduction in \\[Ca2+]i and with NO-donors plus ox-LDL (100 microg of protein/ml). Thrombin (0.03 U/ml) was used as an agonist. In some experiments 8-Br-cGMP (0.5-1 mmol/l) was used to investigate the NO-dependent intraplatelet signalling system. Slightly oxidized LDL was obtained by leaving native LDL in the light at room temperature for at least 7 days. Ox-LDL did not cause any increase in thrombin-induced [Ca2+] (control: 215.4 +/- 44.3 nmol/l, ox-LDL 223.4 +/- 35.3 nmol/l, M +/- SEM; n = 8) and platelet aggregation (control: 78.7 +/- 4.9% , ox-LDL: 78.9 +/- 4.2% , n = 12). Ox-LDL antagonized the effects of NO-donors on platelet [Ca2+]i (NO-donor: 137.4 +/- 22.1 nmol/l, NO + ox-LDL: 177.3 +/- 27.6 nmol/l, n = 11; P < 0.001) and platelet aggregation (NO-donor: 15.4 +/- 3.4% , NO + ox-LDL: 28.9 +/- 3.8%, n = 24; P < 0.001). Ox-LDL did not affect the inhibitory activities of 8-Br-cGMP on platelet aggregation (8-Br-cGMP: 22.0 +/- 8.5%, 8-Br-cGMP + ox-LDL: 19.3 +/- 7.8%, n = 5) and platelet [Ca2+]i . In conclusion, slightly oxidized LDL does not directly activate platelets and does not i affect the intracellular NO-dependent signalling system. The present results suggest that LDL reduces the antiplatelet activity of NO mainly by preventing its biological effects. PMID:16793716

  16. LOX-1 in macrophage migration in response to ox-LDL and the involvement of calpains.

    PubMed

    Wang, Xianwei; Ding, Zufeng; Lin, Juntang; Guo, Zhikun; Mehta, Jawahar L

    2015-11-01

    Previous studies have shown that oxidized low-density lipoprotein (ox-LDL) inhibits macrophage migration, but the precise mechanisms remain unclear. Lectin-like ox-LDL receptor-1 (LOX-1) is a scavenger receptor that is expressed in macrophages and binds ox-LDL. Calpains, a family of calcium-dependent proteases, influence several aspects of cell migration. In this study, we investigated the role of LOX-1 in macrophage migration in response to ox-LDL and the involvement of calpains in this process. Peritoneal macrophages from wild type C57BL/6 mice were exposed to different concentrations of ox-LDL (1-20 μg/mL), and expression of LOX-1 and calpain-1 and -2, cell migration and intracellular calcium (Ca(2+)in) were measured. Our results showed that ox-LDL stimulated LOX-1 and calpain-2 expression, and inhibited calpain-1 expression in a dose- and time-dependent manner. Further, ox-LDL inhibited macrophage migration and increased Ca(2+)in concentration in macrophages. To further elucidate the role of LOX-1 in ox-LDL-impaired macrophage migration, we isolated peritoneal macrophages from LOX-1 knockout mice, and treated them with ox-LDL. Interestingly, calpain-1 expression was much higher, and calpain-2 expression was lower in LOX-1 knockout macrophages than in wild-type macrophages following exposure to ox-LDL. LOX-1 deletion significantly improved macrophage migration and decreased Ca(2+)in concentration. These data indicate that LOX-1 is, at least in part, responsible for the inhibitory effect of ox-LDL on macrophage migration and this process involves calpain-1 and -2. PMID:26393906

  17. Calcium-activated potassium channels mask vascular dysfunction associated with oxidized LDL exposure in rabbit aorta.

    PubMed

    Bocker, J M; Miller, F J; Oltman, C L; Chappell, D A; Gutterman, D D

    2001-05-01

    Endothelium-dependent vasodilation is impaired in atherosclerosis. Oxidized low density lipoprotein (ox-LDL) plays an important role, possibly through alterations in G-protein activation. We examined the effect of acute exposure to ox-LDL on the dilator responses of isolated rabbit aorta segments. We sought also to evaluate the specificity of this dysfunction for dilator stimuli that traditionally operate through a Gi-protein mechanism. Aortic segments were prepared for measurement of isometric tension. After contraction with prostaglandin F2alpha, relaxation to thrombin, adenosine diphosphate (ADP), or the endothelium-independent agonists, sodium nitroprusside (SNP) or papaverine was examined. Maximal relaxation to thrombin was impaired in the presence of ox-LDL (17.7+/-3.7% p<0.05) compared to control (no LDL) (52.6+/-4.0%). Ox-LDL did not affect maximal relaxation to ADP or SNP. However, in the presence of charybdotoxin (CHTX: calcium-activated potassium channel inhibitor) ox-LDL impaired relaxation to ADP (17.4+/-3.2%). CHTX did not affect control (no LDL) responses to ADP (69.6+/-5.0%) or relaxation to thrombin or papaverine. In conclusion, ox-LDL impairs relaxation to thrombin, but in the case of ADP, calcium-activated potassium channels compensate to maintain this relaxation. PMID:11605770

  18. Effects of cyclodextrins on the structure of LDL and its susceptibility to copper-induced oxidation.

    PubMed

    Ao, Meiying; Gan, Chaoye; Shao, Wenxiang; Zhou, Xing; Chen, Yong

    2016-08-25

    Cyclodextrins (CDs) have long been widely used as drug/food carriers and were recently developed as drugs for the treatment of diseases (e.g. Niemann-Pick C1 and cancers). It is unknown whether cyclodextrins may influence the structure of low-density lipoprotein (LDL), its susceptibility to oxidation, and atherogenesis. In this study, four widely used cyclodextrins including α-CD, γ-CD, and two derivatives of β-CD (HPβCD and MβCD) were recruited. Interestingly, agarose gel electrophoresis (staining lipid and protein components of LDL with Sudan Black B and Coomassie brilliant blue, respectively but simultaneously) shows that cyclodextrins at relatively high concentrations caused disappearance of the LDL band and/or appearance of an additional protein-free lipid band, implying that cyclodextrins at relatively high concentrations can induce significant electrophoresis-detectable lipid depletion of LDL. Atomic force microscopy (AFM) detected that MβCD (as a representative of cyclodextrins) induced size decrease of LDL particles in a dose-dependent manner, further confirming the lipid depletion effects of cyclodextrins. Moreover, the data from agarose gel electrophoresis, conjugated diene formation, MDA production, and amino group blockage of copper-oxidized LDL show that cyclodextrins can impair LDL susceptibility to oxidation. It implies that cyclodextrins probably help to inhibit atherogenesis by lowering LDL oxidation. PMID:27140842

  19. [Synthesis and application of the polyacrylamide beads acting as LDL adsorbent's matrices].

    PubMed

    Yu, Xixun; Li, Li; Yue, Yilun; Chen, Huaiqing

    2004-08-01

    This study in pursuit of the synthetic technologies and structure characterization of polyacrylamide-based matrices (PAM beads) for low density lipoprotein (LDL) adsorbent and their adsorbability for LDL was intended for an experimental evidence of developing advanced matrices for LDL adsorbent. PAM beads were synthesized by inverse suspension polymerization, and their structure characterization was characterized by SEM, image analyzer and small angle X-ray scattering. The tripeptide serine-aspartic-glutamic acid (SDE) was coupled on the PAM beads to prepare the LDL adsorbents whose adsorbability for LDL was determined in vitro. The results showed that the PAM beads with the average size diameter 142.1 microm and the average pore diameter 119.8 nm could act as the matrices in accordance with the requirement of adsorbent for LDL. When the amount of acrylamide and the crosslinking agent N,N'-methylene-bis(acrylamide) was fixed, the average pore diameter decreased with the increase of the crosslinking agent content. Although the nonspecific binding of PAM beads for LDL was low, they could selectively adsorb LDL after coupling the SDE on the PAM beads. PMID:15357437

  20. Association of LDL subfractions with clinical cardiovascular outcomes: A systematic review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Context: Low-density lipoprotein (LDL) subfractions have been proposed as an independent risk factor for cardiovascular disease (CVD). Objective: Systematically review the relationship between LDL subfractions and incidence and progression of CVD. Data Sources: Medline, CAB Abstracts, and Cochrane C...

  1. Oxidized LDL levels are increased in HIV infection and may drive monocyte activation

    PubMed Central

    Zidar, David A.; Juchnowski, Steven; Ferrari, Brian; Clagett, Brian; Pilch-Cooper, Heather A.; Rose, Shawn; Rodriguez, Benigno; McComsey, Grace A.; Sieg, Scott F.; Mehta, Nehal N.; Lederman, Michael M.; Funderburg, Nicholas T.

    2015-01-01

    Background Human immunodeficiency virus (HIV) infection is associated with increased cardiovascular risk, and this risk correlates with markers of monocyte activation. We have shown that HIV is associated with a prothrombotic monocyte phenotype, which can be partially mitigated by statin therapy. We therefore explored the relationship between oxidized LDL particles and monocyte activation. Methods We performed phenotypic analysis of monocytes using flow cytometry on fresh whole blood in 54 patients with HIV and 24 controls without HIV. Plasma levels of oxLDL, soluble CD14, IL-6, soluble CD163 were measured by ELISA. In vitro experiments were performed using flow cytometry. Results Plasma levels of oxLDL were significantly increased in HIV-infection compared to controls (60.1 units vs 32.1 units, p<0.001). Monocyte expression of the oxLDL receptors, CD36 and Toll-like receptor 4, were also increased in HIV. OxLDL levels correlated with markers of monocyte activation, including soluble CD14, TF expression on inflammatory monocytes, and CD36. In vitro, stimulation with oxLDL, but not to LDL, resulted in expansion of inflammatory monocytes and increased monocyte expression of TF, recapitulating the monocyte profile we find in HIV disease. Conclusions OxLDL may contribute to monocyte activation and further study in the context of HIV disease is warranted. PMID:25647528

  2. Recombinant RXFP1-LDL-A module does not form dimers.

    PubMed

    Petrie, Emma J; Periguini, Matthew A; Bathgate, Ross A D; Gooley, Paul R

    2013-01-01

    The Relaxin receptor, RXFP1, is a complex G-protein coupled receptor (GPCR). It has a rhodopsin-like 7 transmembrane helix region and a large ecto-domain containing Leucine-rich repeats and a Low Desnsity Lipoprotein Class-A module at the N-terminus. RXFP1 and the closely related receptor for INSL3, RXFP2 are the only mammalian GPCRs to contain an LDL-A module. The LDL-A module has been shown to be essential for receptor signal activation. RXFP1, like other GPCRs, has been shown to form dimers however the interface upon association is currently unknown. As LDL-A modules are commonly found as repeats we hypothesized that the LDL-A module may associate at the dimer interface and play a role in receptor activation. To this end we analyzed the ability for the LDL-A module to oligomerise via Analytical Ultracentrifugation (AUC). PMID:24640556

  3. Effects of different polysaccharides on the formation of egg yolk LDL complex nanogels for nutrient delivery.

    PubMed

    Zhou, Mingyong; Hu, Qiaobin; Wang, Taoran; Xue, Jingyi; Luo, Yangchao

    2016-11-20

    Five polysaccharides, pectin, carboxymethyl cellulose (CMC), gum arabic, carrageenan and alginate, were studied to form complex nanogels with egg yolk low density lipoprotein (LDL). All nanogels were smaller than 85nm with high negative zeta potential, while LDL/carrageenan and LDL/alginate nanogels exhibited more heterogeneous size distribution. Fourier transform infrared spectrum suggested that hydrogen bonds, hydrophobic and electrostatic interactions were involved to form nanogels. Overall, significant expansion of nanogels was observed after encapsulation of curcumin, being studied as a model lipophilic nutrient. Fluorescence spectra evidenced that LDL provided non-polar microenvironment for curcumin and polysaccharides played an important role in the encapsulation process. All nanogels showed sustained release of curcumin under simulated gastrointestinal conditions. Furthermore, nanoscale, smooth and spherical ultrafine dry powders of nanogels were obtained by innovative nano spray drying technology. Our study indicated that LDL/polysaccharides may serve as potential oral delivery systems for lipophilic nutrients. PMID:27561504

  4. Myeloid Cell-Specific ABCA1 Deletion Has Minimal Impact on Atherogenesis in Atherogenic Diet-Fed LDL Receptor Knockout Mice

    PubMed Central

    Bi, Xin; Zhu, Xuewei; Gao, Chuan; Shewale, Swapnil; Cao, Qiang; Liu, Mingxia; Boudyguina, Elena; Gebre, Abraham K.; Wilson, Martha D.; Brown, Amanda L.; Parks, John S.

    2014-01-01

    Objective Transplantation studies suggest that bone marrow (BM) cell ABCA1 protects against atherosclerosis development. However, the in vivo impact of macrophage ABCA1 expression on atherogenesis is not fully understood because BM contains other leukocytes and hematopoietic stem and progenitor cells. Myeloid-specific ABCA1 knockout (MSKO) mice in the LDL receptor knockout (LDLrKO) C57BL/6 background were developed to address this question. Approach and Results Chow-fed MSKO/LDLrKO (DKO) vs. LDLrKO (SKO) mice had similar plasma lipid concentrations, but atherogenic diet (AD)-fed DKO mice had reduced plasma VLDL/LDL concentrations resulting from decreased hepatic VLDL triglyceride secretion. Resident peritoneal macrophages from AD-fed DKO vs. SKO mice had significantly higher cholesterol content, but similar proinflammatory gene expression. Atherosclerosis extent was similar between genotypes after 10–16 wks of AD, but increased modestly in DKO mice by 24 wks of AD. Lesional macrophage content was similar, likely due to higher monocyte flux through aortic root lesions in DKO vs. SKO mice. After transplantation of DKO or SKO BM into SKO mice and 16 wk of AD feeding, atherosclerosis extent was similar and plasma apoB lipoproteins was reduced in mice receiving DKO BM. When differences in plasma VLDL/LDL concentrations were minimized by maintaining mice on chow for 24 wks, DKO mice had modest, but significantly more, atherosclerosis compared to SKO mice. Conclusions Myeloid cell ABCA1 increases hepatic VLDL triglyceride secretion and plasma VLDL/LDL concentrations in AD-fed LDLrKO mice, offsetting its atheroprotective role in decreasing macrophage cholesterol content, resulting in minimal increase in atherosclerosis. PMID:24833800

  5. Anti-inflammatory HDL becomes pro-inflammatory during the acute phase response. Loss of protective effect of HDL against LDL oxidation in aortic wall cell cocultures.

    PubMed Central

    Van Lenten, B J; Hama, S Y; de Beer, F C; Stafforini, D M; McIntyre, T M; Prescott, S M; La Du, B N; Fogelman, A M; Navab, M

    1995-01-01

    We previously reported that high density lipoprotein (HDL) protects against the oxidative modification of low density lipoprotein (LDL) induced by artery wall cells causing these cells to produce pro-inflammatory molecules. We also reported that enzyme systems associated with HDL were responsible for this anti-inflammatory property of HDL. We now report studies comparing HDL before and during an acute phase response (APR) in both humans and a croton oil rabbit model. In rabbits, from the onset of APR the protective effect of HDL progressively decreased and was completely lost by day three. As serum amyloid A (SAA) levels in acute phase HDL (AP-HDL) increased, apo A-I levels decreased 73%. Concomitantly, paraoxonase (PON) and platelet activating factor acetylhydrolase (PAF-AH) levels in HDL declined 71 and 90%, respectively, from days one to three. After day three, there was some recovery of the protective effect of HDL. AP-HDL from human patients and rabbits but not normal or control HDL (C-HDL) exhibited increases in ceruloplasmin (CP). This increase in CP was not seen in acute phase VLDL or LDL. C-HDL incubated with purified CP and re-isolated (CP-HDL), lost its ability to inhibit LDL oxidation. Northern blot analyses demonstrated enhanced expression of MCP-1 in coculture cells treated with AP-HDL and CP-HDL compared to C-HDL. Enrichment of human AP-HDL with purified PON or PAF-AH rendered AP-HDL protective against LDL modification. We conclude that under basal conditions HDL serves an anti-inflammatory role but during APR displacement and/or exchange of proteins associated with HDL results in a pro-inflammatory molecule. Images PMID:8675645

  6. Bis(monoacylglycero)phosphate reduces oxysterol formation and apoptosis in macrophages exposed to oxidized LDL.

    PubMed

    Arnal-Levron, Maud; Chen, Yinan; Delton-Vandenbroucke, Isabelle; Luquain-Costaz, Céline

    2013-07-01

    Atherosclerosis is a major cardiovascular complication of diseases associated with increased oxidative stress that favors oxidation of circulating low density lipoproteins (LDLs). Oxidized LDL (oxLDL) is considered as highly atherogenic as it induces a strong accumulation of cholesterol in subendothelial macrophages leading to the formation of foam cells and emergence of atherosclerotic plaque. OxLDL is enriched in oxidation products of cholesterol called oxysterols, some of which have been involved in the ability of oxLDL to induce cellular oxidative stress and cytotoxicity, mainly by apoptosis. Little is known about the possible contribution of cell-generated oxysterols toward LDL-associated oxysterols in cellular accumulation of oxysterols and related apoptosis. Using both radiochemical and mass analyzes, we showed that oxLDL greatly enhanced oxysterol production by RAW macrophages in comparison with unloaded cells or cells loaded with native LDL. Most oxysterols were produced by non-enzymatic routes (7-ketocholesterol and 7α/β-hydroyxycholesterol) but enzymatically formed 7α-, 25- and 27-hydroxycholesterol were also quantified. Bis(monoacylglycero)phosphate (BMP) is a unique phospholipid preferentially found in late endosomes. We and others have highlighted the role of BMP in the regulation of intracellular cholesterol metabolism/traffic in macrophages. We here report that cellular BMP accumulation was associated with a significantly lower production of oxysterols upon oxLDL exposure. Of note, potent pro-apoptotic 7-ketocholesterol was the most markedly decreased. OxLDL-induced cell cytotoxicity and apoptosis were consistently attenuated in BMP-enriched cells. Taken together, our data suggest that BMP exerts a protective action against the pro-apoptotic effect of oxLDL via a reduced production of intracellular pro-apoptotic oxysterols. PMID:23542536

  7. Oxidized LDL signals through Rho-GTPase to induce endothelial cell stiffening and promote capillary formation.

    PubMed

    Oh, Myung-Jin; Zhang, Chongxu; LeMaster, Elizabeth; Adamos, Crystal; Berdyshev, Evgeny; Bogachkov, Yedida; Kohler, Erin E; Baruah, Jugajyoti; Fang, Yun; Schraufnagel, Dean E; Wary, Kishore K; Levitan, Irena

    2016-05-01

    Endothelial biomechanics is emerging as a key factor in endothelial function. Here, we address the mechanisms of endothelial stiffening induced by oxidized LDL (oxLDL) and investigate the role of oxLDL in lumen formation. We show that oxLDL-induced endothelial stiffening is mediated by CD36-dependent activation of RhoA and its downstream target, Rho kinase (ROCK), via inhibition of myosin light-chain phosphatase (MLCP) and myosin light-chain (MLC)2 phosphorylation. The LC-MS/MS analysis identifies 7-ketocholesterol (7KC) as the major oxysterol in oxLDL. Similarly to oxLDL, 7KC induces RhoA activation, MLCP inhibition, and MLC2 phosphorylation resulting in endothelial stiffening. OxLDL also facilitates formation of endothelial branching networks in 3D collagen gels in vitro and induces increased formation of functional blood vessels in a Matrigel plug assay in vivo. Both effects are RhoA and ROCK dependent. An increase in lumen formation was also observed in response to pre-exposing the cells to 7KC, an oxysterol that induces endothelial stiffening, but not to 5α,6α epoxide that does not affect endothelial stiffness. Importantly, loading cells with cholesterol prevented oxLDL-induced RhoA activation and the downstream signaling cascade, and reversed oxLDL-induced lumen formation. In summary, we show that oxLDL-induced endothelial stiffening is mediated by the CD36/RhoA/ROCK/MLCP/MLC2 pathway and is associated with increased endothelial angiogenic activity. PMID:26989083

  8. Correlation between pretreatment serum LDL-cholesterol levels and prognosis in nasopharyngeal carcinoma patients

    PubMed Central

    Tang, Qiu; Hu, Qiao-Ying; Piao, Yong-feng; Hua, Yong-Hong

    2016-01-01

    Purpose To investigate the correlations between long-term survival outcomes in patients with nasopharyngeal carcinoma (NPC) and pretreatment serum low-density lipoprotein cholesterol (LDL-C) levels. Patients and methods Between January 2008 and December 2011, 935 patients with newly diagnosed NPC who were treated with intensity-modulated radiation therapy were included in this retrospective clinical analysis. Patients were divided into two groups based on pretreatment LDL-C levels: normal LDL-C (≤3.64 mmol/L; n=816) and elevated LDL-C (>3.64 mmol/L; n=119). Associations between pretreatment LDL-C levels and treatment outcome were analyzed by univariate and multivariate analyses. Results The overall patient follow-up rate was 95.1%, and 726 patients received more than 5 years of follow-up. Five-year overall survival (OS), local control (LC), and distant metastasis-free survival (DMFS) rates of the entire patient population were 87.1%, 91.1%, and 87.2%, respectively. Rates of 5-year OS, LC, and DMFS for the elevated versus normal LDL-C groups were 77.0% vs 89.1% (P<0.001), 85.8% vs 91.9% (P=0.041), and 81.1% vs 88.1% (P=0.038), respectively. Compared with normal LDL-C levels, elevated LDL-C levels were identified as an independent prognostic factor of a poorer OS (hazard ratio [HR] =2.171; 95% confidence interval [CI] =1.424–3.309), LC rate (HR =1.762; 95% CI =1.021–3.942), and DMFS (HR =1.594; 95% CI =1.003–2.532). Conclusion This study found that elevated pretreatment LDL-C levels are negative prognostic indicators of NPC. Elevated LDL-C levels may be useful indicators of locoregional control and distant metastasis in NPC patients. PMID:27217776

  9. The role of a conserved acidic residue in calcium-dependent protein folding for a low density lipoprotein (LDL)-A module: implications in structure and function for the LDL receptor superfamily.

    PubMed

    Guo, Ying; Yu, Xuemei; Rihani, Kayla; Wang, Qing-Yin; Rong, Lijun

    2004-04-16

    One common feature of the more than 1,000 complement-type repeats (or low density lipoprotein (LDL)-A modules) found in LDL receptor and the other members of the LDL receptor superfamily is a cluster of five highly conserved acidic residues in the C-terminal region, DXXXDXXDXXDE. However, the role of the third conserved aspartate of these LDL-A modules in protein folding and ligand recognition has not been elucidated. In this report, using a model LDL-A module and several experimental approaches, we demonstrate that this acidic residue, like the other four conserved acidic residues, is involved in calcium-dependent protein folding. These results suggest an alternative calcium coordination conformation for the LDL-A modules. The proposed model provides a plausible explanation for the conservation of this acidic residue among the LDL-A modules. Furthermore, the model can explain why mutations of this residue in human LDL receptor cause familial hypercholesterolemia. PMID:14749324

  10. Implication of Low HDL-c Levels in Patients with Average LDL-c Levels: A Focus on Oxidized LDL, Large HDL Subpopulation, and Adiponectin

    PubMed Central

    Mascarenhas-Melo, Filipa; Sereno, José; Teixeira-Lemos, Edite; Marado, Daniela; Palavra, Filipe; Pinto, Rui; Rocha-Pereira, Petronila; Teixeira, Frederico; Reis, Flávio

    2013-01-01

    To evaluate the impact of low levels of high density lipoprotein cholesterol (HDL-c) on patients with LDL-c average levels, focusing on oxidative, lipidic, and inflammatory profiles. Patients with cardiovascular risk factors (n = 169) and control subjects (n = 73) were divided into 2 subgroups, one of normal HDL-c and the other of low HDL-c levels. The following data was analyzed: BP, BMI, waist circumference and serum glucose Total-c, TGs, LDL-c, oxidized LDL, total HDL-c and subpopulations (small, intermediate, and large), paraoxonase-1 (PON1) activity, hsCRP, uric acid, TNF-α, adiponectin, VEGF, and iCAM1. In the control subgroup with low HDL-c levels, significantly higher values of BP and TGs and lower values of PON1 activity and adiponectin were found, versus control normal HDL-c subgroup. However, differences in patients' subgroups were clearly more pronounced. Indeed, low HDL-c subgroup presented increased HbA1c, TGs, non-HDL-c, Ox-LDL, hsCRP, VEGF, and small HDL-c and reduced adiponectin and large HDL. In addition, Ox-LDL, large-HDL-c, and adiponectin presented interesting correlations with classical and nonclassical markers, mainly in the normal HDL-c patients' subgroup. In conclusion, despite LDL-c average levels, low HDL-c concentrations seem to be associated with a poor cardiometabolic profile in a population with cardiovascular risk factors, which is better evidenced by traditional and nontraditional CV biomarkers, including Ox-LDL, large HDL-c, and adiponectin. PMID:24282340

  11. Arsenic augments the uptake of oxidized LDL by upregulating the expression of lectin-like oxidized LDL receptor in mouse aortic endothelial cells

    SciTech Connect

    Hossain, Ekhtear; Ota, Akinobu; Karnan, Sivasundaram; Damdindorj, Lkhagvasuren; Takahashi, Miyuki; Konishi, Yuko; Konishi, Hiroyuki; Hosokawa, Yoshitaka

    2013-12-15

    Although chronic arsenic exposure is a well-known risk factor for cardiovascular diseases, including atherosclerosis, the molecular mechanism underlying arsenic-induced atherosclerosis remains obscure. Therefore, this study aimed to elucidate this molecular mechanism. We examined changes in the mRNA level of the lectin-like oxidized LDL (oxLDL) receptor (LOX-1) in a mouse aortic endothelial cell line, END-D, after sodium arsenite (SA) treatment. SA treatment significantly upregulated LOX-1 mRNA expression; this finding was also verified at the protein expression level. Flow cytometry and fluorescence microscopy analyses showed that the cellular uptake of fluorescence (Dil)-labeled oxLDL was significantly augmented with SA treatment. In addition, an anti-LOX-1 antibody completely abrogated the augmented uptake of Dil-oxLDL. We observed that SA increased the levels of the phosphorylated forms of nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB)/p65. SA-induced upregulation of LOX-1 protein expression was clearly prevented by treatment with an antioxidant, N-acetylcysteine (NAC), or an NF-κB inhibitor, caffeic acid phenethylester (CAPE). Furthermore, SA-augmented uptake of Dil-oxLDL was also prevented by treatment with NAC or CAPE. Taken together, our results indicate that arsenic upregulates LOX-1 expression through the reactive oxygen species-mediated NF-κB signaling pathway, followed by augmented cellular oxLDL uptake, thus highlighting a critical role of the aberrant LOX-1 signaling pathway in the pathogenesis of arsenic-induced atherosclerosis. - Highlights: • Sodium arsenite (SA) increases LOX-1 expression in mouse aortic endothelial cells. • SA enhances cellular uptake of oxidized LDL in dose-dependent manner. • SA-induced ROS generation enhances phosphorylation of NF-κB. • SA upregulates LOX-1 expression through ROS-activated NF-κB signaling pathway.

  12. Genome wide transcription start sites analysis of Xanthomonas campestris pv. campestris B100 with insights into the gum gene cluster directing the biosynthesis of the exopolysaccharide xanthan.

    PubMed

    Alkhateeb, Rabeaa S; Vorhölter, Frank-Jörg; Rückert, Christian; Mentz, Almut; Wibberg, Daniel; Hublik, Gerd; Niehaus, Karsten; Pühler, Alfred

    2016-05-10

    Xanthomonas campestris pv. campestris (Xcc) is the major producer of the exopolysaccharide xanthan, the commercially most important natural polysaccharide of microbial origin. The current work provides deeper insights into the yet uncharacterized transcriptomic features of the xanthan producing strain Xcc-B100. Towards this goal, RNA sequencing of a library based on the selective enrichment of the 5' ends of native transcripts was performed. This approach resulted in the genome wide identification of 3067 transcription start sites (TSSs) that were further classified based on their genomic positions. Among them, 1545 mapped upstream of an actively transcribed CDS and 1363 were classified as novel TSSs representing antisense, internal, and TSSs belonging to previously unidentified genomic features. Analyzing the transcriptional strength of primary and antisense TSSs revealed that in some instances antisense transcription seemed to be initiated at a higher level than its sense counterpart. Mapping the exact positions of TSSs aided in the identification of promoter consensus motifs, ribosomal binding sites, and enhanced the genome annotation of 159 in silico predicted translational start (TLS) sites. The global view on length distribution of the 5' untranslated regions (5'-UTRs) deduced from the data pointed to the occurrence of leaderless transcripts and transcripts with unusually long 5'-UTRs, in addition to identifying seven putative riboswitch elements for Xcc-B100. Concerning the biosynthesis of xanthan, we focused on the transcriptional organization of the gum gene cluster. Under the conditions tested, we present evidence for a complex transcription pattern of the gum genes with multiple TSSs and an obvious considerable role of antisense transcription. The gene gumB, encoding an outer membrane xanthan exporter, is presented here as an example for genes that possessed a strong antisense TSS. PMID:26975844

  13. Distribution of the LDL receptor within clathrin-coated pits and caveolae in rat and human liver.

    PubMed

    Ivaturi, Soumya; Wooten, Catherine J; Nguyen, Maikhanh D; Ness, Gene C; Lopez, Dayami

    2014-03-01

    Several findings suggest that the low-density lipoprotein (LDL) receptor may internalize different lipoprotein particles via diverse pathways. Using a combination of discontinuous sucrose gradients and Triton solubilization studies, we demonstrated that the LDL receptor could be located simultaneously in clathrin-coated pits and caveolae in rat and human liver and in human hepatocyte-like C3A cells. Treatment with the cholesterol biosynthesis inhibitor, zaragozic acid A, shifted the distribution of the LDL receptor to clathrin containing fractions, whereas treatment with cholesterol or LDL shifted the receptor distribution towards caveolin-1 containing fractions. The LDL-dependent shift of the LDL receptor to caveolae coincided with a reduction in internalization of Bodipy-LDL. Redistribution within plasma membrane microdomains in response to specific treatments resulting in changes in LDL receptor function represents a novel paradigm that could be exploited in the development of a new class of therapeutic drugs. PMID:24530906

  14. Physiology and pathophysiology of oxLDL uptake by vascular wall cells in atherosclerosis.

    PubMed

    Di Pietro, Natalia; Formoso, Gloria; Pandolfi, Assunta

    2016-09-01

    Atherosclerosis is a progressive disease in which endothelial cell dysfunction, macrophage foam cell formation, and smooth muscle cell migration and proliferation, lead to the loss of vascular homeostasis. Oxidized low-density lipoprotein (oxLDL) may play a pre-eminent function in atherosclerotic lesion formation, even if their role is still debated. Several types of scavenger receptors (SRs) such as SR-AI/II, SRBI, CD36, lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), toll-like receptors (TLRs) and others can promote the internalization of oxLDL. They are expressed on the surface of vascular wall cells (endothelial cells, macrophages and smooth muscle cells) and they mediate the cellular effects of oxLDL. The key influence of both oxLDL and SRs on the atherogenic process has been established in atherosclerosis-prone animals, in which antioxidant treatment and/or silencing of SRs has been shown to reduce atherogenesis. Despite some discrepancies, the indication from cohort studies that there is an association between oxLDL and cardiovascular (CV) events seems to point toward a role for oxLDL in atherosclerotic plaque progress and disruption. Finally, randomized clinical trials using antioxidants have demonstrated benefits only in high-risk patients, suggesting that additional proofs are still needed to better define the involvement of each type of modified LDL in the development of atherosclerosis. PMID:27256928

  15. The Effect of LDL-Apheresis and Rheohaemapheresis Treatment on Vitamin E.

    PubMed

    Solichová, Dagmar; Bláha, Milan; Aufartová, Jana; Krcmová, Lenka Kujovská; Plíšek, Jirí; Honegrová, Barbora; Kasalová, Eva; Lánská, Miriam; Urbánek, Lubor; Sobotka, Luboš

    2015-01-01

    Lipid apheresis (extracorporeal lipoprotein elimination) is administered to patients with familial hypercholesterolemia who fail to respond to standard therapy. The nature of the treatment process raises the suspicion that it decreases not only cholesterol but also antioxidants. A group of 12 patients (average age 47±17 y, 4 homozygous and 8 heterozygous individuals) with familial hypercholesterolemia treated by LDL-apheresis or rheohaemapheresis for 3-12 y was included in the study. In addition to cholesterol and triacylglycerol levels, vitamin E and vitamin A and also other markers of antioxidant activity were investigated. Nevertheless, the most important determined parameter was the vitamin E/cholesterol ratio in serum and lipoproteins. The results indicate that both extracorporeal elimination methods are effective and suitable ways to treat severe familial hypercholesterolemia, as the LDL fraction of cholesterol decreased by approximately 77% and 66% following LDL-apheresis and rheohaemapheresis, respectively. In addition, the serum vitamin E decreased by 54% and 57% and the decrease of the serum vitamin A was approximately 20%. However, the main marker of antioxidant capacity, vitamin E/cholesterol ratio, in the serum, VLDL and LDL significantly increased. The increase of vitamin E levels in the erythrocyte membranes of 2% following LDL-apheresis and a significant increase of 4% following rheohaemapheresis were confirmed. The presented results indicate that LDL-apheresis and rheohaemapheresis can be considered to be safe procedures according to the antioxidant capacity of the serum, VLDL and LDL lipoprotein fractions and the erythrocyte membrane. PMID:26052140

  16. HDAC9 regulates ox-LDL-induced endothelial cell apoptosis by participating in inflammatory reactions.

    PubMed

    Han, Xu; Han, Xiang; Wang, Zheng; Shen, Junjun; Dong, Qiang

    2016-01-01

    Atherosclerosis is the most common cause of cardiovascular diseases worldwide. The endothelial cell apoptosis elicited by oxidized low-density lipoprotein (ox-LDL), which contributes to endothelial damage and inflammation, is a particularly important event in the early stage of atherosclerosis. However, the mechanism underlying ox-LDL-induced endothelial cell apoptosis remains unclear. Here we found that HDAC9 expression was increased at both the mRNA and protein levels accompanied by dose-dependent ox-LDL-induced endothelial cell apoptosis. Depletion of HDAC9 by its specific shRNA significantly antagonized ox-LDL-induced cell apoptosis and suppressed the expression of ox-LDL-induced inflammatory factors, such as TNF-alpha and MCP1. These data suggest that HDAC9 is an important epigenetic factor regulating ox-LDL-induced endothelial cell apoptosis and inflammatory factor expression. These results suggest that HDAC9 may participate in ox-LDL-induced endothelial damage and inflammation during atherosclerosis development. PMID:27100479

  17. Some questions concerning a small, more electronegative LDL circulating in human plasma.

    PubMed

    Avogaro, P; Cazzolato, G; Bittolo-Bon, G

    1991-11-01

    Atherosclerosis and its complications are prevalent worldwide with a high prevalence in western societies. The disease may sometimes be explained by a defect of low density lipoprotein (LDL) specific receptors. However, the prevalence of receptor defect is rather rare and a large body of evidence supports the possibility that an alternative pathway, the so-called "scavenger pathway", constitutes the gate through which cholesterol enters into the parietal wall and gives origin to the "foam cell". Experimental work has clearly demonstrated that LDL may be modified under the action of chemical and biological offenders, all of which make the LDL an "alien". Some papers suggest that the modifications of LDL may occur also "in vivo" in the microenvironment of the vascular vall. In 1988 we were able to record two LDL subfractions in human plasma; the more electronegative minor subfraction shares many of the peculiar traits of LDLs modified "in vitro". The present article stresses all the points which support the hypothesis that the small more electronegative LDL circulating modified LDL, may represent a certain amount of possibly oxidative in origin. PMID:1811552

  18. Clinically used selective oestrogen receptor modulators increase LDL receptor activity in primary human lymphocytes

    PubMed Central

    Cerrato, F; Fernández-Suárez, M E; Alonso, R; Alonso, M; Vázquez, C; Pastor, O; Mata, P; Lasunción, M A; Gómez-Coronado, D

    2015-01-01

    Background and Purpose Treatment with selective oestrogen receptor modulators (SERMs) reduces low-density lipoprotein (LDL) cholesterol levels. We assessed the effect of tamoxifen, raloxifene and toremifene and their combinations with lovastatin on LDL receptor activity in lymphocytes from normolipidaemic and familial hypercholesterolaemic (FH) subjects, and human HepG2 hepatocytes and MOLT-4 lymphoblasts. Experimental Approach Lymphocytes were isolated from peripheral blood, treated with different compounds, and 1,1′-dioctadecyl-3,3,3,3′-tetramethylindocarbocyanine perchlorate (DiI)-labelled LDL uptake was analysed by flow cytometry. Key Results Tamoxifen, toremifene and raloxifene, in this order, stimulated DiI-LDL uptake by lymphocytes by inhibiting LDL-derived cholesterol trafficking and subsequent down-regulation of LDL receptor expression. Differently to what occurred in HepG2 and MOLT-4 cells, only tamoxifen consistently displayed a potentiating effect with lovastatin in primary lymphocytes. The SERM-mediated increase in LDL receptor activity was not altered by the anti-oestrogen ICI 182 780 nor was it reproduced by 17β-oestradiol. However, the tamoxifen-active metabolite endoxifen was equally effective as tamoxifen. The SERMs produced similar effects on LDL receptor activity in heterozygous FH lymphocytes as in normal lymphocytes, although none of them had a potentiating effect with lovastatin in heterozygous FH lymphocytes. The SERMs had no effect in homozygous FH lymphocytes. Conclusions and Implications Clinically used SERMs up-regulate LDL receptors in primary human lymphocytes. There is a mild enhancement between SERMs and lovastatin of lymphocyte LDLR activity, the potentiation being greater in HepG2 and MOLT-4 cells. The effect of SERMs is independent of oestrogen receptors but is preserved in the tamoxifen-active metabolite endoxifen. This mechanism may contribute to the cholesterol-lowering action of SERMs. PMID:25395200

  19. Oxidized LDL impair adipocyte response to insulin by activating serine/threonine kinases.

    PubMed

    Scazzocchio, Beatrice; Varì, Rosaria; D'Archivio, Massimo; Santangelo, Carmela; Filesi, Carmelina; Giovannini, Claudio; Masella, Roberta

    2009-05-01

    Oxidized LDL (oxLDL) increase in patients affected by type-2 diabetes, obesity, and metabolic syndrome. Likewise, insulin resistance, an impaired responsiveness of target tissues to insulin, is associated with those pathological conditions. To investigate a possible causal relationship between oxLDL and the onset of insulin resistance, we evaluated the response to insulin of 3T3-L1 adipocytes treated with oxLDL. We observed that oxLDL inhibited glucose uptake (-40%) through reduced glucose transporter 4 (GLUT4) recruitment to the plasma membrane (-70%), without affecting GLUT4 gene expression. These findings were associated to the impairment of insulin signaling. Specifically, in oxLDL-treated cells insulin receptor (IR) substrate-1 (IRS-1) was highly degraded likely because of the enhanced Ser(307)phosphorylation. This process was largely mediated by the activation of the inhibitor of kappaB-kinase beta (IKKbeta) and the c-Jun NH(2)-terminal kinase (JNK). Moreover, the activation of IKKbeta positively regulated the nuclear content of nuclear factor kappaB (NF-kappaB), by inactivating the inhibitor of NF-kappaB (IkappaBalpha). The activated NF-kappaB further impaired per se GLUT4 functionality. Specific inhibitors of IKKbeta, JNK, and NF-kappaB restored insulin sensitivity in adipocytes treated with oxLDL. These data provide the first evidence that oxLDL, by activating serine/threonine kinases, impaired adipocyte response to insulin affecting pathways involved in the recruitment of GLUT4 to plasma membranes (PM). This suggests that oxLDL might participate in the development of insulin resistance. PMID:19136667

  20. Oxidized LDL impair adipocyte response to insulin by activating serine/threonine kinases

    PubMed Central

    Scazzocchio, Beatrice; Varì, Rosaria; D'Archivio, Massimo; Santangelo, Carmela; Filesi, Carmelina; Giovannini, Claudio; Masella, Roberta

    2009-01-01

    Oxidized LDL (oxLDL) increase in patients affected by type-2 diabetes, obesity, and metabolic syndrome. Likewise, insulin resistance, an impaired responsiveness of target tissues to insulin, is associated with those pathological conditions. To investigate a possible causal relationship between oxLDL and the onset of insulin resistance, we evaluated the response to insulin of 3T3-L1 adipocytes treated with oxLDL. We observed that oxLDL inhibited glucose uptake (−40%) through reduced glucose transporter 4 (GLUT4) recruitment to the plasma membrane (−70%), without affecting GLUT4 gene expression. These findings were associated to the impairment of insulin signaling. Specifically, in oxLDL-treated cells insulin receptor (IR) substrate-1 (IRS-1) was highly degraded likely because of the enhanced Ser307phosphorylation. This process was largely mediated by the activation of the inhibitor of κB-kinase β (IKKβ) and the c-Jun NH2-terminal kinase (JNK). Moreover, the activation of IKKβ positively regulated the nuclear content of nuclear factor κB (NF-κB), by inactivating the inhibitor of NF-κB (IκBα). The activated NF-κB further impaired per se GLUT4 functionality. Specific inhibitors of IKKβ, JNK, and NF-κB restored insulin sensitivity in adipocytes treated with oxLDL. These data provide the first evidence that oxLDL, by activating serine/threonine kinases, impaired adipocyte response to insulin affecting pathways involved in the recruitment of GLUT4 to plasma membranes (PM). This suggests that oxLDL might participate in the development of insulin resistance. PMID:19136667

  1. CD36 Binds Oxidized Low Density Lipoprotein (LDL) in a Mechanism Dependent upon Fatty Acid Binding*

    PubMed Central

    Jay, Anthony G.; Chen, Alexander N.; Paz, Miguel A.; Hung, Justin P.; Hamilton, James A.

    2015-01-01

    The association of unesterified fatty acid (FA) with the scavenger receptor CD36 has been actively researched, with focuses on FA and oxidized low density lipoprotein (oxLDL) uptake. CD36 has been shown to bind FA, but this interaction has been poorly characterized to date. To gain new insights into the physiological relevance of binding of FA to CD36, we characterized FA binding to the ectodomain of CD36 by the biophysical method surface plasmon resonance. Five structurally distinct FAs (saturated, monounsaturated (cis and trans), polyunsaturated, and oxidized) were pulsed across surface plasmon resonance channels, generating association and dissociation binding curves. Except for the oxidized FA HODE, all FAs bound to CD36, with rapid association and dissociation kinetics similar to HSA. Next, to elucidate the role that each FA might play in CD36-mediated oxLDL uptake, we used a fluorescent oxLDL (Dii-oxLDL) live cell assay with confocal microscopy imaging. CD36-mediated uptake in serum-free medium was very low but greatly increased when serum was present. The addition of exogenous FA in serum-free medium increased oxLDL binding and uptake to levels found with serum and affected CD36 plasma membrane distribution. Binding/uptake of oxLDL was dependent upon the FA dose, except for docosahexaenoic acid, which exhibited binding to CD36 but did not activate the uptake of oxLDL. HODE also did not affect oxLDL uptake. High affinity FA binding to CD36 and the effects of each FA on oxLDL uptake have important implications for protein conformation, binding of other ligands, functional properties of CD36, and high plasma FA levels in obesity and type 2 diabetes. PMID:25555908

  2. A nonsense mutation in the LDL receptor gene leads to familial hypercholesterolemia in the Druze sect

    SciTech Connect

    Landsberger, D.; Meiner, V.; Reshef, A.; Leitersdorf, E. ); Levy, Yishai ); Westhytzen, D.R. van der; Coetzee, G.A. )

    1992-02-01

    Familial hypercholesterolemia (FH) is an autosomal dominant disease caused by mutations in the LDL receptor gene. Here the authors characterize and LDL receptor mutation that is associated with a distinct haplotype and causes FH in the Druze, a small Middle Eastern Islamic sect with a high degree of inbreeding. The mutation was found in FH families from two distinct Druze villages from the Golan Heights (northern Israel). It was not found either in another Druze FH family residing in a different geographical area nor in eight Arab and four Jewish FH heterozygote index cases whose hypercholesterolemia cosegregates with an identical LDL receptor gene haplotype. The mutation, a single-base substitution, results in a termination codon in exon 4 of the LDL receptor gene that encodes for the fourth repeat of the binding domain of the mature receptor. It can be diagnosed by allele-specific oligonucleotide hybridization of PCR-amplified DNA from FH patients.

  3. The autoantibody repertoire against copper- or macrophage-modified LDL differs in normolipidemics and hypercholesterolemic patients.

    PubMed

    Fernvik, Eva C; Ketelhuth, Daniel F J; Russo, Momtchilo; Gidlund, Magnus

    2004-03-01

    We have analyzed the antibody repertoire from normo- and hypercholesterolemic subjects to investigate how it can be related to macrophage-dependent modification of low-density lipoproteins, in comparison to the commonly used copper-oxidized LDL. Preexisting natural antibodies in plasma from normo- and hypercholesterolemic individuals were tested for their reactivity against copper ion oxidized LDL and LDL modified by macrophages. A crosswise comparison between these two antigen preparations demonstrated a different antibody repertoire in normo- and hypercholesterolemic patients. This study suggest that the search for antibodies that can influence the progression or regression of an atherosclerotic process has to take into account the process by which LDL is modified, and the repertoire of antibodies that is generated in the normal population, in comparison to that with, or at risk for, coronary artery diseases. PMID:15024184

  4. Oxidized-LDL induce the expression of heat shock protein 70 in human endothelial cells.

    PubMed

    Zhu, W; Roma, P; Pellegatta, F; Catapano, A L

    1994-04-15

    Heat shock proteins are detectable in human atherosclerotic plaques, especially in endothelial cells. In this report we show by immunofluorescence that incubation "in vitro" with OxLDL is a stress capable of inducing the expression of heat shock protein 70 in both the EAhy-926 cell line and human umbilical vein endothelial cells (HUVEC). This induction was parallel to the cytotoxicity of oxidized LDL as determined by [3H]adenine release. When cells were confluent, however, both effects were greatly reduced. We speculate that induction of hsp70 is related to the cytotoxicity of oxidized LDL and that the detection of heat shock proteins in human atherosclerotic plaques is a further indication for the presence "in vivo" of oxidized LDL. These observations may be relevant to the understanding of endothelial response to injury in proatherosclerotic events. PMID:8166710

  5. Hypobetalipoproteinemic mice with a targeted apolipoprotein (Apo) B-27.6-specifying mutation: in vivo evidence for an important role of amino acids 1254-1744 of ApoB in lipid transport and metabolism of the apoB-containing lipoprotein.

    PubMed

    Chen, Zhouji; Fitzgerald, Robin L; Schonfeld, Gustav

    2002-04-19

    Carboxyl-terminal deletion of apoB-100 may impair its triglyceride (TG)-transporting capability and alter its catabolism. Here, we compare our newly generated apoB gene (Apob)-targeted apoB-27.6-bearing mice to our previously reported apoB-38.9 mice to understand further the relationship between the size of a truncated apoB variant and its function/metabolism in vivo. The apoB-27.6-specifying mutation produces a premature stop codon six amino acids (aa) downstream of the last codon of mouse Apob exon 24 (corresponding to aa 1254 of human apoB-100). ApoB-27.6 transcripts were 3- and 5-fold more abundant than apoB wild type and apoB-38.9 transcripts in the liver. Likewise, hepatic secretion rates of apoB-27.6 were 7-fold higher than those of apoB-48 and apoB-38.9. In contrast, apoB-27.6 heterozygotes (Apob(27.6/+)) had lower hepatic TG secretion rates and higher liver TG contents than both apoB-38.9 heterozygotes (Apob(38.9/+)) and apoB wild type mice (Apob(+/+)). ApoB-27.6 was secreted by Apob(27.6/+) hepatocytes as dense high density lipoprotein particles. Moreover, despite its high secretion rates, apoB-27.6 was barely detectable in plasma. Disruption of apoE gene in Apob(38.9/+) and Apob(27.6/+) dramatically increased plasma levels of apoB-38.9 as well as apoB-48 but caused no change in plasma apoB-27.6 concentrations. Finally, the birth rate of apoB-27.6 homozygotes (Apob(27.6/27.6)) from intercrosses of Apob(27.6/+) was 7-fold lower than that of Apob(38.9/38.9) from Apob(38.9/+) intercrosses (1.8% versus 12%). Crossbreeding of Apob(27.6/27.6) and Apob(38.9/38.9) produced viable Apob(27.6/38.9) offspring, but Apob(27.6/27.6) intercrosses produced no offspring. Together, these results demonstrate in vivo that the apoB-27.6-apoB-38.9 peptide segment (aa 1254-1744) plays a critical role, not only in supporting hepatic TG-secretion and in modulating catabolism of apoB-containing lipoproteins, but also in normal mouse embryonic development. PMID:11839763

  6. Oxidized LDL induces an oxidative stress and activates the tumor suppressor p53 in MRC5 human fibroblasts.

    PubMed

    Mazière, C; Meignotte, A; Dantin, F; Conte, M A; Mazière, J C

    2000-09-24

    It is now well established that oxidized LDL (OxLDL) is involved in the progression of the atheromatous plaque via several mechanisms, including its cytotoxicity toward the arterial wall. Our study demonstrates that a 4-h incubation of cultured human fibroblasts with 25-75 microg/ml OxLDL induced a dose-dependent increase in the intracellular levels of reactive oxygen species (ROS) and lipid peroxidation end products (TBARS). This effect was markedly prevented by the antioxidant vitamin E. The lipid extract of OxLDL partially reproduced the action of the LDL particle itself. Concomitantly, OxLDL enhanced the DNA binding activity of p53 measured by electrophoretic mobility shift assay, and the intracellular protein level of p53 determined by immunoblot analysis. Cycloheximide prevented the OxLDL-induced augmentation in both p53 binding activity and intracellular level. Again, the lipid extract of OxLDL reproduced the effect of OxLDL on p53 binding activity, whereas vitamin E prevented it. These results indicate that OxLDL initiates an intracellular oxidative stress by means of its lipid peroxidation products, leading to the activation of the tumour suppressor p53 by enhancement of p53 protein synthesis. This effect might be related to the cytotoxic effect of OxLDL since the activation of p53 is known to lead to cell cycle arrest, necrosis or apoptosis. PMID:11027537

  7. Paraoxonase 1-treated oxLDL promotes cholesterol efflux from macrophages by stimulating the PPARγ-LXRα-ABCA1 pathway.

    PubMed

    Ikhlef, Souade; Berrougui, Hicham; Kamtchueng Simo, Olivier; Khalil, Abdelouahed

    2016-06-01

    Here, we investigate the mechanism through which paraoxonase 1 (PON1) may regulate cholesterol efflux. Pretreatment of oxLDL with PON1 (oxLDL-PON1) contributed to the formation of LysoPC. In J774 macrophages, oxLDL-PON1 increased cholesterol efflux by more than 47% compared to oxLDL alone. oxLDL-PON1 significantly increased mRNA and protein expression of ABCA1 and ABCG1, as well as of PPARγ and LXRα compared to oxLDL alone. Intraperitoneal injection of oxLDL-PON1- or LysoPC-treated J774 macrophages significantly increased the fecal elimination of macrophage-derived cholesterol in these mice. Our results suggest that PON1 stimulates cholesterol efflux via a mechanism that involves oxidized phospholipid hydrolysis. PMID:27148853

  8. Effect of the endothelial glycocalyx layer on arterial LDL transport under normal and high pressure.

    PubMed

    Liu, Xiao; Fan, Yubo; Deng, Xiaoyan

    2011-08-21

    To quantitatively investigate the role of the endothelial glycocalyx layer (EGL) in protecting the artery from excessive infiltration of atherogenic lipids such as low density lipoproteins (LDLs), a multilayer model with the EGL of an arterial segment was developed to numerically simulate the flow and the transport of LDLs under normal and high pressure. The transport parameters of the layers of the model were obtained from the hydrodynamic theory, the stochastic theory, and from the literature. The results showed that the increase in the thickness of the EGL could lead to a sharp drop in LDL accumulation in the intima. A partial damage to the EGL could compromise its barrier function, hence leading to enhanced infiltration/accumulation of LDLs within the wall of the arterial model. Without the EGL, hypertension could lead to a significantly enhanced LDL transport into the wall of the model. However, the intact EGL could protect the arterial wall from hypertension so that the LDL concentration in the intima layer was almost the same as that under normal pressure conditions. The results also showed that LDL concentration within the arterial wall increased with Φ (the fraction of leaky junctions) on the intima layer. The increase in LDL concentration with Φ was much more dramatic for the model without the EGL. For instance, without the EGL, a Φ of 0.0005 could lead LDL concentration within the arterial wall to be even higher than that predicted for the EGL intact model with a Φ of 0.002. In conclusion, an intact EGL with a sufficient thickness may act as a barrier to LDL infiltration into the arterial wall and has the potential to suppress the hypertension-driven hike of LDL infiltration/accumulation in the arterial wall. PMID:21645523

  9. Diet rich in high glucoraphanin broccoli reduces plasma LDL cholesterol: Evidence from randomised controlled trials

    PubMed Central

    Armah, Charlotte N; Derdemezis, Christos; Traka, Maria H; Dainty, Jack R; Doleman, Joanne F; Saha, Shikha; Leung, Wing; Potter, John F; Lovegrove, Julie A; Mithen, Richard F

    2015-01-01

    Scope Cruciferous-rich diets have been associated with reduction in plasma LDL-cholesterol (LDL-C), which may be due to the action of isothiocyanates derived from glucosinolates that accumulate in these vegetables. This study tests the hypothesis that a diet rich in high glucoraphanin (HG) broccoli will reduce plasma LDL-C. Methods and results One hundred and thirty volunteers were recruited to two independent double-blind, randomly allocated parallel dietary intervention studies, and were assigned to consume either 400 g standard broccoli or 400 g HG broccoli per week for 12 weeks. Plasma lipids were quantified before and after the intervention. In study 1 (37 volunteers), the HG broccoli diet reduced plasma LDL-C by 7.1% (95% CI: –1.8%, –12.3%, p = 0.011), whereas standard broccoli reduced LDL-C by 1.8% (95% CI +3.9%, –7.5%, ns). In study 2 (93 volunteers), the HG broccoli diet resulted in a reduction of 5.1% (95% CI: –2.1%, –8.1%, p = 0.001), whereas standard broccoli reduced LDL-C by 2.5% (95% CI: +0.8%, –5.7%, ns). When data from the two studies were combined the reduction in LDL-C by the HG broccoli was significantly greater than standard broccoli (p = 0.031). Conclusion Evidence from two independent human studies indicates that consumption of high glucoraphanin broccoli significantly reduces plasma LDL-C. PMID:25851421

  10. Serum LDL (Low Density Lipoprotein) As a Risk Factor for Ischemic Stroke.

    PubMed

    Biswas, N; Sangma, M A

    2016-07-01

    Atherosclerosis is the main risk factor of ischaemic stroke. Dyslipidaemia is the main cause of atherosclerosis. High levels of LDL, also called "bad" cholesterol, seem to provoke stroke. This case control study was conducted in Mymensingh Medical College Hospital during the period of January 2012 to December 2012. The study was carried out to measure the level of serum LDL (Low Density Lipoprotein) of ischaemic stroke patients admitted in Medicine wards of Mymensingh Medical College Hospital and the result of this study was compared with the level of LDL cholesterol in age matched controls. Sample size was 384 which had been selected by inclusion and exclusion criteria. Out of 384 samples 192 were cases and 192 were controls. Mean age ±SD was 57.0±10.85 years in cases and 57.43±10.64 years in controls. Elderly people are the most vulnerable group for developing stroke. LDL cholesterol level was more than 130mg/dl was found 88.54% among cases and 33.85% among controls, the difference was statistically significant (p<0.05). Mean LDL level ±SD were 145±13.59mg/dl in cases and 125.01±10.73mg/dl in controls. Odds ratio of LDL cholesterol were 15.0979 and 95% confidence limits were 8.8396 to 25.7869 among cases and controls. This study explored study population with higher LDL cholesterol was over fifteen times more likely to developed ischaemic stroke. Early detection of high LDL cholesterol in the way to prevent ischaemic stroke and thereby reduced the morbidity and mortality of ischaemic stroke. PMID:27612886

  11. Statin-exposed vascular smooth muscle cells secrete proteoglycans with decreased binding affinity for LDL.

    PubMed

    Meyers, C Daniel; Tannock, Lisa R; Wight, Thomas N; Chait, Alan

    2003-11-01

    Retention of LDL in the artery intima is mediated by extracellular matrix proteoglycans and plays an important role in the initiation of atherosclerosis. Compared with quiescent cells, proliferating smooth muscle cells secrete proteoglycans with elongated glycosaminoglycan side chains, which have an increased binding affinity to LDL. Because 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors (statins) decrease smooth muscle cell proliferation, we hypothesized that statin exposure would decrease both the size and LDL binding affinity of vascular proteoglycans. Monkey aortic smooth muscle cells grown in culture were exposed to simvastatin (10 and 100 microM) and cerivastatin (0.1 and 1 microM), and newly secreted proteoglycans were quantified and characterized. Both simvastatin and cerivastatin caused a concentration-dependent reduction in cell growth and reduced 35SO4 incorporation into secreted proteoglycans, on both an absolute and a per cell basis. Interestingly, statin exposure increased the apparent molecular weight and hydrodynamic size of secreted proteoglycans. However, proteoglycans secreted from statin-exposed cells demonstrated a reduction in binding affinity to LDL. Thus, statins may induce atheroprotective changes in vascular proteoglycans and lower LDL retention in the vessel wall. These findings suggest a mechanism whereby statins may benefit atherosclerosis in a manner unrelated to serum LDL lowering. PMID:12923222

  12. Mechanism of transfer of LDL-derived free cholesterol to HDL subfractions in human plasma

    SciTech Connect

    Miida, T.; Fielding, C.J.; Fielding, P.E. )

    1990-11-01

    The transfer of ({sup 3}H)cholesterol in low-density lipoprotein (LDL) to different high-density lipoprotein (HDL) species in native human plasma was determined by using nondenaturing two-dimensional electrophoresis. Transfer from LDL had a t{sub 1/2} at 37{degree}C of 51 {plus minus} 8 min and an activation energy of 18.0 kCal mol{sup {minus}1}. There was unexpected specificity among HDL species as acceptors of LDL-derived labeled cholesterol. The largest fraction of the major {alpha}-migrating class (HDL{sub 2b}) was the major initial acceptor of LDL-derived cholesterol. Kinetic analysis indicated a rapid secondary transfer from HDL{sub 2b} to smaller {alpha}HDL (particularly HDL{sub 3}) driven enzymatically by the lecithin-cholesterol acyltransferase reaction. Rates of transfer among {alpha}HDL were most rapid from the largest {alpha}HDL fraction (HDL{sub 2b}), suggesting possible protein-mediated facilitation. Simultaneous measurements of the transport of LDL-derived and cell-derived isotopic cholesterol indicated that the former preferably utilized the {alpha}HDL pathyway, with little label in pre-{beta}HDL. The same experiments confirmed earlier data that cell-derived cholesterol is preferentially channeled through pre-{beta}HDL. The authors suggest that the functional heterogeneity of HDL demonstrated here includes the ability to independently process cell- and LDL-derived free cholesterol.

  13. The glycosylation-dependent interaction of perlecan core protein with LDL: implications for atherosclerosis[S

    PubMed Central

    Xu, Yu-Xin; Ashline, David; Liu, Li; Tassa, Carlos; Shaw, Stanley Y.; Ravid, Katya; Layne, Matthew D.; Reinhold, Vernon; Robbins, Phillips W.

    2015-01-01

    Perlecan is a major heparan sulfate (HS) proteoglycan in the arterial wall. Previous studies have linked it to atherosclerosis. Perlecan contains a core protein and three HS side chains. Its core protein has five domains (DI–DV) with disparate structures and DII is highly homologous to the ligand-binding portion of LDL receptor (LDLR). The functional significance of this domain has been unknown. Here, we show that perlecan DII interacts with LDL. Importantly, the interaction largely relies on O-linked glycans that are only present in the secreted DII. Among the five repeat units of DII, most of the glycosylation sites are from the second unit, which is highly divergent and rich in serine and threonine, but has no cysteine residues. Interestingly, most of the glycans are capped by the negatively charged sialic acids, which are critical for LDL binding. We further demonstrate an additive effect of HS and DII on LDL binding. Unlike LDLR, which directs LDL uptake through endocytosis, this study uncovers a novel feature of the perlecan LDLR-like DII in receptor-mediated lipoprotein retention, which depends on its glycosylation. Thus, perlecan glycosylation may play a role in the early LDL retention during the development of atherosclerosis. PMID:25528754

  14. Oxidation of LDL by myeloperoxidase and reactive nitrogen species: reaction pathways and antioxidant protection.

    PubMed

    Carr, A C; McCall, M R; Frei, B

    2000-07-01

    Oxidative modification of low density lipoprotein (LDL) appears to play an important role in atherogenesis. Although the precise mechanisms of LDL oxidation in vivo are unknown, several lines of evidence implicate myeloperoxidase and reactive nitrogen species, in addition to ceruloplasmin and 15-lipoxygenase. Myeloperoxidase generates a number of reactive species, including hypochlorous acid, chloramines, tyrosyl radicals, and nitrogen dioxide. These reactive species oxidize the protein, lipid, and antioxidant components of LDL. Modification of apolipoprotein B results in enhanced uptake of LDL by macrophages with subsequent formation of lipid-laden foam cells. Nitric oxide synthases produce nitric oxide and, under certain conditions, superoxide radicals. Numerous other sources of superoxide radicals have been identified in the arterial wall, including NAD(P)H oxidases and xanthine oxidase. Nitric oxide and superoxide readily combine to form peroxynitrite, a reactive nitrogen species capable of modifying LDL. In this review, we examine the reaction pathways involved in LDL oxidation by myeloperoxidase and reactive nitrogen species and the potential protective effects of the antioxidant vitamins C and E. PMID:10894808

  15. Prevalence of LDL atherogenic phenotype in patients with systemic lupus erythematosus

    PubMed Central

    Olusi, Samuel O; George, Sunila

    2011-01-01

    Background: Patients with systemic lupus erythematosus (SLE) are 5–8 times more likely to develop coronary heart disease than the general population. The aim of this study was to find out the prevalence of the small dense low-density lipoprotein (LDL) cholesterol particle in patients with SLE. Methods: We recruited 50 consecutive patients with SLE who had no evidence of hypertension or renal failure. Fifty age- and gender-matched healthy controls were also recruited. We measured serum lipid levels and LDL particle diameters by gradient gel electrophoresis in both patients and controls. Results: Patients with SLE had significant dyslipidemia, characterized by elevated plasma triglycerides, LDL cholesterol, Apoprotein B, triglyceride:high-density (HDL) lipoprotein cholesterol ratio, and decreased plasma concentrations of HDL cholesterol. The LDL particle size in SLE (24.8 ± 1.23 nm) was significantly (P < 0.01) smaller than that in controls (26.1 ± 1.31 nm). The prevalence of the LDL phenotype B (the atherogenic phenotype) was 52% in SLE but only 20% in healthy controls. Conclusion: We conclude that the high prevalence of small dense LDL in SLE may contribute to the high incidence of coronary heart disease seen in this disorder. PMID:21415920

  16. Gentiana scabra Reduces SR-A Expression and Oxidized-LDL Uptake in Human Macrophages

    PubMed Central

    Lin, Chin-Sheng; Liu, Pang-Yen; Lian, Chen-Hao; Lin, Ching-Heng; Lai, Jenn-Haung; Ho, Ling-Jun; Yang, Shih-Ping; Cheng, Shu-Meng

    2016-01-01

    Background Macrophages can imbibe low-density lipoprotein (LDL) through scavenger receptors to become foam cells, which is critical in the initiation and progression of atherosclerosis. Mounting evidence suggests that the anti-inflammatory nature of Chinese herbs have the capacity to halt the complex mechanisms underlying atherosclerosis. This study examined the effects of Chinese herbs on foam cell formation. Methods Chinese herbs were obtained from the Sun Ten pharmaceutic company. Using oxidized LDL (OxLDL) uptake and a cell toxicity assay, we screened more than 30 types of Chinese herbs. Western blotting was used to determine expressions of scavenger receptors (SRs) and extracellular-signal-regulated kinase (ERK) activities. Results We found that Gentiana scabra reduced oxidized LDL uptake effectively in THP-1 macrophages (p < 0.05 vs. OxLDL treated control). Moreover, treatment with Gentiana scabra in THP-1 macrophages resulted in decreased expression of scavenger receptor- A (SR-A) (p < 0.05 vs. control). Molecular investigation revealed that Gentiana scabra inhibited SR-A protein expression, possibly by regulating ERK signaling pathways (p < 0.05 vs. control). Conclusions By regulating SR-A expression, Gentiana scabra reduced oxidized LDL uptake in human macrophages. These results support the potential use of Gentiana scabra in treating atherosclerosis. PMID:27471359

  17. Whole-Exome Sequencing Identifies Rare and Low-Frequency Coding Variants Associated with LDL Cholesterol

    PubMed Central

    Lange, Leslie A.; Hu, Youna; Zhang, He; Xue, Chenyi; Schmidt, Ellen M.; Tang, Zheng-Zheng; Bizon, Chris; Lange, Ethan M.; Smith, Joshua D.; Turner, Emily H.; Jun, Goo; Kang, Hyun Min; Peloso, Gina; Auer, Paul; Li, Kuo-ping; Flannick, Jason; Zhang, Ji; Fuchsberger, Christian; Gaulton, Kyle; Lindgren, Cecilia; Locke, Adam; Manning, Alisa; Sim, Xueling; Rivas, Manuel A.; Holmen, Oddgeir L.; Gottesman, Omri; Lu, Yingchang; Ruderfer, Douglas; Stahl, Eli A.; Duan, Qing; Li, Yun; Durda, Peter; Jiao, Shuo; Isaacs, Aaron; Hofman, Albert; Bis, Joshua C.; Correa, Adolfo; Griswold, Michael E.; Jakobsdottir, Johanna; Smith, Albert V.; Schreiner, Pamela J.; Feitosa, Mary F.; Zhang, Qunyuan; Huffman, Jennifer E.; Crosby, Jacy; Wassel, Christina L.; Do, Ron; Franceschini, Nora; Martin, Lisa W.; Robinson, Jennifer G.; Assimes, Themistocles L.; Crosslin, David R.; Rosenthal, Elisabeth A.; Tsai, Michael; Rieder, Mark J.; Farlow, Deborah N.; Folsom, Aaron R.; Lumley, Thomas; Fox, Ervin R.; Carlson, Christopher S.; Peters, Ulrike; Jackson, Rebecca D.; van Duijn, Cornelia M.; Uitterlinden, André G.; Levy, Daniel; Rotter, Jerome I.; Taylor, Herman A.; Gudnason, Vilmundur; Siscovick, David S.; Fornage, Myriam; Borecki, Ingrid B.; Hayward, Caroline; Rudan, Igor; Chen, Y. Eugene; Bottinger, Erwin P.; Loos, Ruth J.F.; Sætrom, Pål; Hveem, Kristian; Boehnke, Michael; Groop, Leif; McCarthy, Mark; Meitinger, Thomas; Ballantyne, Christie M.; Gabriel, Stacey B.; O’Donnell, Christopher J.; Post, Wendy S.; North, Kari E.; Reiner, Alexander P.; Boerwinkle, Eric; Psaty, Bruce M.; Altshuler, David; Kathiresan, Sekar; Lin, Dan-Yu; Jarvik, Gail P.; Cupples, L. Adrienne; Kooperberg, Charles; Wilson, James G.; Nickerson, Deborah A.; Abecasis, Goncalo R.; Rich, Stephen S.; Tracy, Russell P.; Willer, Cristen J.; Gabriel, Stacey B.; Altshuler, David M.; Abecasis, Gonçalo R.; Allayee, Hooman; Cresci, Sharon; Daly, Mark J.; de Bakker, Paul I.W.; DePristo, Mark A.; Do, Ron; Donnelly, Peter; Farlow, Deborah N.; Fennell, Tim; Garimella, Kiran; Hazen, Stanley L.; Hu, Youna; Jordan, Daniel M.; Jun, Goo; Kathiresan, Sekar; Kang, Hyun Min; Kiezun, Adam; Lettre, Guillaume; Li, Bingshan; Li, Mingyao; Newton-Cheh, Christopher H.; Padmanabhan, Sandosh; Peloso, Gina; Pulit, Sara; Rader, Daniel J.; Reich, David; Reilly, Muredach P.; Rivas, Manuel A.; Schwartz, Steve; Scott, Laura; Siscovick, David S.; Spertus, John A.; Stitziel, Nathaniel O.; Stoletzki, Nina; Sunyaev, Shamil R.; Voight, Benjamin F.; Willer, Cristen J.; Rich, Stephen S.; Akylbekova, Ermeg; Atwood, Larry D.; Ballantyne, Christie M.; Barbalic, Maja; Barr, R. Graham; Benjamin, Emelia J.; Bis, Joshua; Boerwinkle, Eric; Bowden, Donald W.; Brody, Jennifer; Budoff, Matthew; Burke, Greg; Buxbaum, Sarah; Carr, Jeff; Chen, Donna T.; Chen, Ida Y.; Chen, Wei-Min; Concannon, Pat; Crosby, Jacy; Cupples, L. Adrienne; D’Agostino, Ralph; DeStefano, Anita L.; Dreisbach, Albert; Dupuis, Josée; Durda, J. Peter; Ellis, Jaclyn; Folsom, Aaron R.; Fornage, Myriam; Fox, Caroline S.; Fox, Ervin; Funari, Vincent; Ganesh, Santhi K.; Gardin, Julius; Goff, David; Gordon, Ora; Grody, Wayne; Gross, Myron; Guo, Xiuqing; Hall, Ira M.; Heard-Costa, Nancy L.; Heckbert, Susan R.; Heintz, Nicholas; Herrington, David M.; Hickson, DeMarc; Huang, Jie; Hwang, Shih-Jen; Jacobs, David R.; Jenny, Nancy S.; Johnson, Andrew D.; Johnson, Craig W.; Kawut, Steven; Kronmal, Richard; Kurz, Raluca; Lange, Ethan M.; Lange, Leslie A.; Larson, Martin G.; Lawson, Mark; Lewis, Cora E.; Levy, Daniel; Li, Dalin; Lin, Honghuang; Liu, Chunyu; Liu, Jiankang; Liu, Kiang; Liu, Xiaoming; Liu, Yongmei; Longstreth, William T.; Loria, Cay; Lumley, Thomas; Lunetta, Kathryn; Mackey, Aaron J.; Mackey, Rachel; Manichaikul, Ani; Maxwell, Taylor; McKnight, Barbara; Meigs, James B.; Morrison, Alanna C.; Musani, Solomon K.; Mychaleckyj, Josyf C.; Nettleton, Jennifer A.; North, Kari; O’Donnell, Christopher J.; O’Leary, Daniel; Ong, Frank; Palmas, Walter

    2014-01-01

    Elevated low-density lipoprotein cholesterol (LDL-C) is a treatable, heritable risk factor for cardiovascular disease. Genome-wide association studies (GWASs) have identified 157 variants associated with lipid levels but are not well suited to assess the impact of rare and low-frequency variants. To determine whether rare or low-frequency coding variants are associated with LDL-C, we exome sequenced 2,005 individuals, including 554 individuals selected for extreme LDL-C (>98th or <2nd percentile). Follow-up analyses included sequencing of 1,302 additional individuals and genotype-based analysis of 52,221 individuals. We observed significant evidence of association between LDL-C and the burden of rare or low-frequency variants in PNPLA5, encoding a phospholipase-domain-containing protein, and both known and previously unidentified variants in PCSK9, LDLR and APOB, three known lipid-related genes. The effect sizes for the burden of rare variants for each associated gene were substantially higher than those observed for individual SNPs identified from GWASs. We replicated the PNPLA5 signal in an independent large-scale sequencing study of 2,084 individuals. In conclusion, this large whole-exome-sequencing study for LDL-C identified a gene not known to be implicated in LDL-C and provides unique insight into the design and analysis of similar experiments. PMID:24507775

  18. Whole-exome sequencing identifies rare and low-frequency coding variants associated with LDL cholesterol.

    PubMed

    Lange, Leslie A; Hu, Youna; Zhang, He; Xue, Chenyi; Schmidt, Ellen M; Tang, Zheng-Zheng; Bizon, Chris; Lange, Ethan M; Smith, Joshua D; Turner, Emily H; Jun, Goo; Kang, Hyun Min; Peloso, Gina; Auer, Paul; Li, Kuo-Ping; Flannick, Jason; Zhang, Ji; Fuchsberger, Christian; Gaulton, Kyle; Lindgren, Cecilia; Locke, Adam; Manning, Alisa; Sim, Xueling; Rivas, Manuel A; Holmen, Oddgeir L; Gottesman, Omri; Lu, Yingchang; Ruderfer, Douglas; Stahl, Eli A; Duan, Qing; Li, Yun; Durda, Peter; Jiao, Shuo; Isaacs, Aaron; Hofman, Albert; Bis, Joshua C; Correa, Adolfo; Griswold, Michael E; Jakobsdottir, Johanna; Smith, Albert V; Schreiner, Pamela J; Feitosa, Mary F; Zhang, Qunyuan; Huffman, Jennifer E; Crosby, Jacy; Wassel, Christina L; Do, Ron; Franceschini, Nora; Martin, Lisa W; Robinson, Jennifer G; Assimes, Themistocles L; Crosslin, David R; Rosenthal, Elisabeth A; Tsai, Michael; Rieder, Mark J; Farlow, Deborah N; Folsom, Aaron R; Lumley, Thomas; Fox, Ervin R; Carlson, Christopher S; Peters, Ulrike; Jackson, Rebecca D; van Duijn, Cornelia M; Uitterlinden, André G; Levy, Daniel; Rotter, Jerome I; Taylor, Herman A; Gudnason, Vilmundur; Siscovick, David S; Fornage, Myriam; Borecki, Ingrid B; Hayward, Caroline; Rudan, Igor; Chen, Y Eugene; Bottinger, Erwin P; Loos, Ruth J F; Sætrom, Pål; Hveem, Kristian; Boehnke, Michael; Groop, Leif; McCarthy, Mark; Meitinger, Thomas; Ballantyne, Christie M; Gabriel, Stacey B; O'Donnell, Christopher J; Post, Wendy S; North, Kari E; Reiner, Alexander P; Boerwinkle, Eric; Psaty, Bruce M; Altshuler, David; Kathiresan, Sekar; Lin, Dan-Yu; Jarvik, Gail P; Cupples, L Adrienne; Kooperberg, Charles; Wilson, James G; Nickerson, Deborah A; Abecasis, Goncalo R; Rich, Stephen S; Tracy, Russell P; Willer, Cristen J

    2014-02-01

    Elevated low-density lipoprotein cholesterol (LDL-C) is a treatable, heritable risk factor for cardiovascular disease. Genome-wide association studies (GWASs) have identified 157 variants associated with lipid levels but are not well suited to assess the impact of rare and low-frequency variants. To determine whether rare or low-frequency coding variants are associated with LDL-C, we exome sequenced 2,005 individuals, including 554 individuals selected for extreme LDL-C (>98(th) or <2(nd) percentile). Follow-up analyses included sequencing of 1,302 additional individuals and genotype-based analysis of 52,221 individuals. We observed significant evidence of association between LDL-C and the burden of rare or low-frequency variants in PNPLA5, encoding a phospholipase-domain-containing protein, and both known and previously unidentified variants in PCSK9, LDLR and APOB, three known lipid-related genes. The effect sizes for the burden of rare variants for each associated gene were substantially higher than those observed for individual SNPs identified from GWASs. We replicated the PNPLA5 signal in an independent large-scale sequencing study of 2,084 individuals. In conclusion, this large whole-exome-sequencing study for LDL-C identified a gene not known to be implicated in LDL-C and provides unique insight into the design and analysis of similar experiments. PMID:24507775

  19. Biological activity of some naturally occurring resins, gums and pigments against in vitro LDL oxidation.

    PubMed

    Andrikopoulos, Nikolaos K; Kaliora, Andriana C; Assimopoulou, Andreana N; Papapeorgiou, Vassilios P

    2003-05-01

    Naturally occurring gums and resins with beneficial pharmaceutical and nutraceutical properties were tested for their possible protective effect against copper-induced LDL oxidation in vitro. Chiosmastic gum (CMG) (Pistacia lentiscus var. Chia resin) was the most effective in protecting human LDL from oxidation. The minimum and maximum doses for the saturation phenomena of inhibition of LDL oxidation were 2.5 mg and 50 mg CMG (75.3% and 99.9%, respectively). The methanol/water extract of CMG was the most effective compared with other solvent combinations. CMG when fractionated in order to determine a structure-activity relationship showed that the total mastic essential oil, collofonium-like residue and acidic fractions of CMG exhibited a high protective activity ranging from 65.0% to 77.8%. The other natural gums and resins (CMG resin 'liquid collection', P. terebinthus var. Chia resin, dammar resin, acacia gum, tragacanth gum, storax gum) also tested as above, showed 27.0%-78.8% of the maximum LDL protection. The other naturally occurring substances, i.e. triterpenes (amyrin, oleanolic acid, ursolic acid, lupeol, 18-a-glycyrrhetinic acid) and hydroxynaphthoquinones (naphthazarin, shikonin and alkannin) showed 53.5%-78.8% and 27.0%-64.1% LDL protective activity, respectively. The combination effects (68.7%-76.2% LDL protection) of ursolic-, oleanolic- and ursodeoxycholic- acids were almost equal to the effect (75.3%) of the CMG extract in comparable doses. PMID:12748987

  20. ApoA-IV promotes the biogenesis of apoA-IV-containing HDL particles with the participation of ABCA1 and LCAT[S

    PubMed Central

    Duka, Adelina; Fotakis, Panagiotis; Georgiadou, Dimitra; Kateifides, Andreas; Tzavlaki, Kalliopi; von Eckardstein, Leonard; Stratikos, Efstratios; Kardassis, Dimitris; Zannis, Vassilis I.

    2013-01-01

    The objective of this study was to establish the role of apoA-IV, ABCA1, and LCAT in the biogenesis of apoA-IV-containing HDL (HDL-A-IV) using different mouse models. Adenovirus-mediated gene transfer of apoA-IV in apoA-I−/− mice did not change plasma lipid levels. ApoA-IV floated in the HDL2/HDL3 region, promoted the formation of spherical HDL particles as determined by electron microscopy, and generated mostly α- and a few pre-β-like HDL subpopulations. Gene transfer of apoA-IV in apoA-I−/− × apoE−/− mice increased plasma cholesterol and triglyceride levels, and 80% of the protein was distributed in the VLDL/IDL/LDL region. This treatment likewise generated α- and pre-β-like HDL subpopulations. Spherical and α-migrating HDL particles were not detectable following gene transfer of apoA-IV in ABCA1−/− or LCAT−/− mice. Coexpression of apoA-IV and LCAT in apoA-I−/− mice restored the formation of HDL-A-IV. Lipid-free apoA-IV and reconstituted HDL-A-IV promoted ABCA1 and scavenger receptor BI (SR-BI)-mediated cholesterol efflux, respectively, as efficiently as apoA-I and apoE. Our findings are consistent with a novel function of apoA-IV in the biogenesis of discrete HDL-A-IV particles with the participation of ABCA1 and LCAT, and may explain previously reported anti-inflammatory and atheroprotective properties of apoA-IV. PMID:23132909

  1. Short-term treatment with a 2-carba analog of cyclic phosphatidic acid induces lowering of plasma cholesterol levels in ApoE-deficient mice.

    PubMed

    Tsukahara, Tamotsu; Haniu, Hisao; Matsuda, Yoshikazu; Murakmi-Murofushi, Kimiko

    2016-04-22

    Plasma cholesterol levels are associated with an increased risk of developing atherosclerosis. An elevated low-density lipoprotein cholesterol (LDL-C) level is a hallmark of hypercholesterolemia in metabolic syndrome. Our previous study suggested that when acetylated LDL (AC-LDL) was co-applied with a PPARγ agonist, rosiglitazone (ROSI), many oil red O-positive macrophages could be observed. However, addition of cyclic phosphatidic acid (cPA) to ROSI-stimulated macrophages completely abolished oil red O-stained cells, indicating that cPA inhibits PPARγ-regulated AC-LDL uptake. This study aimed to determine whether metabolically stabilized cPA, in the form of a carba-derivative of cPA (2ccPA), could reduce plasma cholesterol levels and affect the expression of genes related to atherosclerosis in apolipoprotein E-knockout (apoE(-/-)) mice. 2ccPA reduced LDL-C levels in these mice (n = 3) from 460 to 330 mg/ml, from 420 to 350 mg/ml, and 420 to 281 mg/ml under a western-type diet. 2ccPA also reduced expression of lipid metabolism-related genes, cytokines, and chemokines in ApoE-deficient mice on a high-fat diet. Taken together, these results suggest that 2ccPA governs anti-atherogenic activities in the carotid arteries of apoE-deficient mice. PMID:27012212

  2. The effect of HDL-bound and free PON1 on copper-induced LDL oxidation.

    PubMed

    Bayrak, Ahmet; Bayrak, Tülin; Bodur, Ebru; Kılınç, Kamer; Demirpençe, Ediz

    2016-09-25

    Oxidative modification of LDL plays an important role in the development of atherosclerosis. High-density lipoprotein (HDL) confers protection against atherosclerosis and the antioxidative properties of paraoxonase 1 (PON1) has been suggested to contribute to this effect of HDL. The PON1 exist in two major polymorphic forms (Q and R), which regulate the concentration and activity of the enzyme and alter its ability to prevent lipid oxidation. However, the association of Q192R polymorphism with PON1's capacity to protect against LDL lipoperoxidation is controversial. The aim of this study was to evaluate the effects of the purified PON1 Q192R and the partially purified HDL-bound PON1 Q192R isoenzymes (HDL-PON1 Q192R) on LDL oxidation, with respect to their arylesterase/homocysteine thiolactonase (HTLase) activities. Cupric ion-induced LDL oxidation was reduced up to 48% by purified PON1 Q192, but only 33% by an equivalent activity of PON1 R192. HDL-PON1 Q192 isoenzyme caused a 65% reduction, whereas HDL-PON1 R192 isoenzyme caused only 46% reduction in copper ion-induced LDL oxidation. These findings reflect the fact that PON1 Q and PON1 R allozymes may have different protective characteristics against LDL oxidation. The protection against LDL oxidation provided by HDL-PON1 Q192R isoenzymes is more prominent than the purified soluble enzymes. Inhibition of the Ca(+2)-dependent PON1 Q192R arylesterase/HTLase by the metal chelator EDTA, did not alter PON1's ability to inhibit LDL oxidation. These studies indicate that the active site involvement of the purified enzyme is not similar to the HDL-bound one, in terms of both PON1 arylesterase/HTLase activity and the protection of LDL from copper ion-induced oxidation. Moreover, PON1's ability to protect LDL from oxidation does not seem to require calcium. PMID:27510818

  3. apo B gene knockout in mice results in embryonic lethality in homozygotes and neural tube defects, male infertility, and reduced HDL cholesterol ester and apo A-I transport rates in heterozygotes.

    PubMed Central

    Huang, L S; Voyiaziakis, E; Markenson, D F; Sokol, K A; Hayek, T; Breslow, J L

    1995-01-01

    apo B is a structural constituent of several classes of lipoprotein particles, including chylomicrons, VLDL, and LDL. To better understand the role of apo B in the body, we have used gene targeting in embryonic stem cells to create a null apo B allele in the mouse. Homozygous apo B deficiency led to embryonic lethality, with resorption of all embryos by gestational day 9. Heterozygotes showed an increased tendency to intrauterine death with some fetuses having incomplete neural tube closure and some live-born heterozygotes developing hydrocephalus. The majority of male heterozygotes were sterile, although the genitourinary system and sperm were grossly normal. Viable heterozygotes had normal triglycerides, but total, LDL, and HDL cholesterol levels were decreased by 37, 37, and 39%, respectively. Hepatic and intestinal apo B mRNA levels were decreased in heterozygotes, presumably contributing to the decreased LDL levels through decreased synthesis of apo B-containing lipoproteins. Kinetic studies indicated that heterozygotes had decreased transport rates of HDL cholesterol ester and apo A-I. As liver and intestinal apo A-I mRNA levels were unchanged, the mechanism for decreased apo A-I transport must be posttranscriptional. Heterozygotes also had normal cholesterol absorption and a normal response of the plasma lipoprotein pattern to chronic consumption of a high fat, high cholesterol, Western-type diet. In summary, we report a mouse model for apo B deficiency with several phenotypic features that were unexpected based on clinical studies of apo B-deficient humans, such as embryonic lethality in homozygotes and neural tube closure defects, male infertility, and a major defect in HDL production in heterozygotes. This model presents an opportunity to study the mechanisms underlying these phenotypic changes. Images PMID:7593600

  4. Refinement of variant selection for the LDL-C genetic risk score in the diagnosis of the polygenic form of clinical Familial Hypercholesterolemia and replication in samples from six countries

    PubMed Central

    Futema, Marta; Shah, Sonia; Cooper, Jackie A; Li, KaWah; Whittall, Ros A; Sharifi, Mahtab; Goldberg, Olivia; Drogari, Euridiki; Mollaki, Vasiliki; Wiegman, Albert; Defesche, Joep; D’Agostino, Maria N; D’Angelo, Antonietta; Rubba, Paolo; Fortunato, Giuliana; Walus-Miarka, Małgorzata; Hegele, Robert A; Bamimore, Mary Aderayo; Durst, Ronen; Leitersdorf, Eran; Mulder, Monique T; Roeters van Lennep, Janine E; Sijbrands, Eric J G; Whittaker, John C; Talmud, Philippa J; Humphries, Steve E

    2016-01-01

    Background Familial Hypercholesterolemia (FH) is an autosomal-dominant disorder caused by mutations in one of three genes. In the 60% of patients who are mutation-negative we have recently shown that the clinical phenotype can be associated with an accumulation of common small-effect LDL-C-raising alleles using a 12-SNP score. The aims of the study were to improve the selection of SNPs, and to replicate the results in additional samples. Methods Receiver-operating characteristic curves were used to determine the optimum number of LDL-C SNPs. For replication analysis, we genotyped patients with a clinical diagnosis of FH from six countries for six LDL-C-associated alleles. We compared the weighted SNP score among patients with no confirmed mutation (FH/M-), those with a mutation (FH/M+), and controls from an UK population sample (WHII). Results Increasing the number of SNPs to 33 did not improve the ability of the score to discriminate between FH/M- and controls, while sequential removal of SNPs with smaller effects/lower frequency showed a weighted score of six SNPs performed as well as the 12-SNP score. Meta-analysis of the weighted 6-SNP score, based on polymorphisms in CELSR2, APOB, ABCG5/8, LDLR and APOE loci, in the independent FH/M- cohorts showed a consistently higher score in comparison to the WHII population (P<2.2×10-16). Modeling in individuals with a 6-SNP score in the top three quarters of the score distribution, indicated a >95% likelihood of a polygenic explanation of their increased LDL-C. Conclusion A 6-SNP LDL-C score consistently distinguishes FH/M- patients from healthy subjects. The hypercholesterolemia in 88% of mutation-negative patients is likely to have a polygenic basis. PMID:25414277

  5. Dietary cladode powder from wild type and domesticated Opuntia species reduces atherogenesis in apoE knock-out mice.

    PubMed

    Garoby-Salom, Sandra; Guéraud, Françoise; Camaré, Caroline; de la Rosa, Ana-Paulina Barba; Rossignol, Michel; Santos Díaz, María del Socorro; Salvayre, Robert; Negre-Salvayre, Anne

    2016-03-01

    Dietary intake of Opuntia species may prevent the development of cardiovascular diseases. The present study was designed to characterize the biological antioxidant and anti-inflammatory properties of Opuntia species and to investigate whether Opuntia cladodes prevent the development of atherosclerosis in vivo, in apoE(-)KO mice. The effects of the two Opuntia species, the wild Opuntia streptacantha and the domesticated Opuntia ficus-indica, were tested on the generation of intra- and extracellular reactive oxygen species (ROS) production and kinetics of the LDL oxidation by murine CRL2181 endothelial cells and on the subsequent inflammatory signaling leading to the adhesion of monocytes on the activated endothelium and the formation of foam cells. Opuntia species blocked the extracellular ROS (superoxide anion) generation and LDL oxidation by CRL2181, as well as the intracellular ROS rise and signaling evoked by the oxidized LDL, including the nuclear translocation of the transcription factor NFκB, the expression of ICAM-1 and VCAM-1 adhesion molecules, and the adhesion of monocytes to CRL2181. In vivo, Opuntia significantly reduced the formation of atherosclerotic lesions and the accumulation of 4-hydroxynonenal adducts in the vascular wall of apoE-KO mice, indicating that Opuntia cladodes prevent lipid oxidation in the vascular wall. In conclusion, wild and domesticated Opuntia species exhibit antioxidant, anti-inflammatory, and antiatherogenic properties which emphasize their nutritional benefit for preventing cardiovascular diseases. PMID:26704378

  6. Leucine supplementation via drinking water reduces atherosclerotic lesions in apoE null mice

    PubMed Central

    Zhao, Yang; Dai, Xiao-yan; Zhou, Zhou; Zhao, Ge-xin; Wang, Xian; Xu, Ming-jiang

    2016-01-01

    Aim: Recent evidence suggests that the essential amino acid leucine may be involved in systemic cholesterol metabolism. In this study, we investigated the effects of leucine supplementation on the development of atherosclerosis in apoE null mice. Methods: ApoE null mice were fed with chow supplemented with leucine (1.5% w/v) in drinking water for 8 week. Aortic atherosclerotic lesions were examined using Oil Red O staining. Plasma lipoprotein-cholesterol levels were measured with fast protein liquid chromatography. Hepatic gene expression was detected using real-time PCR and Western blot analyses. Results: Leucine supplementation resulted in 57.6% reduction of aortic atherosclerotic lesion area in apoE null mice, accompanied by 41.2% decrease of serum LDL-C levels and 40.2% increase of serum HDL-C levels. The body weight, food intake and blood glucose level were not affected by leucine supplementation. Furthermore, leucine supplementation increased the expression of Abcg5 and Abcg8 (that were involved in hepatic cholesterol efflux) by 1.28- and 0.86-fold, respectively, and significantly increased their protein levels. Leucine supplementation also increased the expression of Srebf1, Scd1 and Pgc1b (that were involved in hepatic triglyceride metabolism) by 3.73-, 1.35- and 1.71-fold, respectively. Consequently, leucine supplementation resulted in 51.77% reduction of liver cholesterol content and 2.2-fold increase of liver triglyceride content. Additionally, leucine supplementation did not affect the serum levels of IL-6, IFN-γ, TNF-α, IL-10 and IL-12, but markedly decreased the serum level of MCP-1. Conclusion: Leucine supplementation effectively attenuates atherosclerosis in apoE null mice by improving the plasma lipid profile and reducing systemic inflammation. PMID:26687933

  7. Modulation of lipoprotein metabolism by inhibition of sphingomyelin synthesis in ApoE knockout mice.

    PubMed

    Park, Tae-Sik; Panek, Robert L; Rekhter, Mark D; Mueller, Sandra Bak; Rosebury, Wendy S; Robertson, Andrew; Hanselman, Jeffrey C; Kindt, Erick; Homan, Reynold; Karathanasis, Sotirios K

    2006-12-01

    Plasma sphingomyelin (SM) has been suggested as a risk factor for coronary heart disease independent of cholesterol levels. A decrease of SM in lipoproteins is known to improve the activities of lecithin:cholesterol acyltransferase (LCAT) and lipoprotein lipase (LPL) in vitro. Inhibition of SM biosynthesis may reduce lipoprotein SM content and thus improve cholesterol distribution in lipoproteins by enhancing reverse cholesterol transport and clearance of triglyceride-rich lipoproteins. To examine this hypothesis, ApoE KO mice were fed a western diet and treated for 4 weeks with various concentrations of myriocin, a specific inhibitor of serine palmitoyltransferase. Myriocin treatment lowered plasma cholesterol and TG levels in a dose-dependent manner. In addition, myriocin treatment reduced cholesterol contents in VLDL and LDL and elevated HDL-cholesterol. Observed lipid-lowering effects of myriocin were associated with suppression of HMG CoA reductase and fatty acid synthase via reduced levels of SREBP-1 RNA and protein. Induction of apoAI and lecithin:cholesterol acytransferase (LCAT) in the liver by myriocin was associated with an increased HDL. Lesion area and macrophage area were also diminished in the cuffed femoral artery of ApoE KO mice. In conclusion, inhibition of sphingolipid biosynthesis can be a novel therapeutic target for dyslipidemia and atherosclerosis. PMID:16458317

  8. Anticoagulant activity of tissue factor pathway inhibitor in human plasma is preferentially associated with dense subspecies of LDL and HDL and with Lp(a).

    PubMed

    Lesnik, P; Vonica, A; Guérin, M; Moreau, M; Chapman, M J

    1993-07-01

    Human plasma contains a multivalent, Kunitz-type proteinase inhibitor termed tissue factor pathway inhibitor (TFPI), which specifically inhibits the action of the factor VII(a)-tissue factor complex in coagulation. In the present study, we examined the distribution and anticoagulant activity of TFPI among plasma lipoprotein subspecies separated by isopycnic density gradient ultracentrifugation; this procedure permitted the simultaneous fractionation of the major lipoprotein classes (very-low-density lipoprotein [VLDL], intermediate-density lipoprotein [IDL], low-density lipoprotein [LDL], high-density lipoprotein [HDL] 2 and 3, and very-high-density lipoprotein [VHDL]). Studies of eight normolipidemic subjects revealed two major lipoprotein carriers of TFPI activity: dense LDL subspecies (d = 1.039 to 1.063 g/mL) and both dense HDL particles and VHDL (d = 1.133 to 1.190 g/mL), representing 33.8% and 35.9%, respectively, of the total lipoprotein-associated TFPI activity in plasma. TFPI activity was also associated with lipoprotein(a) (Lp[a]), whose density distribution (d = 1.044 to 1.100 g/mL) overlapped that of LDL and HDL2; such association was related to Lp(a)'s particle size and phenotype. VLDL, IDL, and LDL1 through LDL3 (d = 1.019 to 1.039 g/mL), HDL2 (d = 1.063 to 1.100 g/mL), and light subfractions of HDL3 (d = 1.100 to 1.167 g/mL) conveyed only 1.8%, 10%, and 18.5%, respectively, of lipoprotein-associated TFPI activity. Such anticoagulant activity was dependent on the presence of TFPI protein. The dense subspecies of HDL3 (d = 1.133 to 1.167 g/mL) with which TFPI was preferentially associated were small, displayed a cholesteryl ester to protein ratio of approximately 0.2, and were deficient in phospholipid (13.6% to 18.3%). HDL subspecies of d = 1.110 to 1.167 g/mL mainly contained the higher relative molecular mass form of TFPI of 41 kD (a form that is known to be covalently associated with apolipoprotein [apo] A-II) and minor bands of the 35- and 52-k

  9. Increased LDL electronegativity in chronic kidney disease disrupts calcium homeostasis resulting in cardiac dysfunction.

    PubMed

    Chang, Kuan-Cheng; Lee, An-Sheng; Chen, Wei-Yu; Lin, Yen-Nien; Hsu, Jing-Fang; Chan, Hua-Chen; Chang, Chia-Ming; Chang, Shih-Sheng; Pan, Chia-Chi; Sawamura, Tatsuya; Chang, Chi-Tzong; Su, Ming-Jai; Chen, Chu-Huang

    2015-07-01

    Chronic kidney disease (CKD), an independent risk factor for cardiovascular disease, is associated with abnormal lipoprotein metabolism. We examined whether electronegative low-density lipoprotein (LDL) is mechanistically linked to cardiac dysfunction in patients with early CKD. We compared echocardiographic parameters between patients with stage 2 CKD (n = 88) and normal controls (n = 89) and found that impaired relaxation was more common in CKD patients. Reduction in estimated glomerular filtration rate was an independent predictor of left ventricular relaxation dysfunction. We then examined cardiac function in a rat model of early CKD induced by unilateral nephrectomy (UNx) by analyzing pressure-volume loop data. The time constant of isovolumic pressure decay was longer and the maximal velocity of pressure fall was slower in UNx rats than in controls. When we investigated the mechanisms underlying relaxation dysfunction, we found that LDL from CKD patients and UNx rats was more electronegative than LDL from their respective controls and that LDL from UNx rats induced intracellular calcium overload in H9c2 cardiomyocytes in vitro. Furthermore, chronic administration of electronegative LDL, which signals through lectin-like oxidized LDL receptor-1 (LOX-1), induced relaxation dysfunction in wild-type but not LOX-1(-/-) mice. In in vitro and in vivo experiments, impaired cardiac relaxation was associated with increased calcium transient resulting from nitric oxide (NO)-dependent nitrosylation of SERCA2a due to increases in inducible NO synthase expression and endothelial NO synthase uncoupling. In conclusion, LDL becomes more electronegative in early CKD. This change disrupts SERCA2a-regulated calcium homeostasis, which may be the mechanism underlying cardiorenal syndrome. PMID:25871829

  10. Freezing canine sperm: comparison of semen extenders containing Equex and LDL (Low Density Lipoproteins).

    PubMed

    Bencharif, Djemil; Amirat-Briand, Lamia; Garand, Annabelle; Anton, Marc; Schmitt, Eric; Desherces, Serge; Delhomme, Guy; Langlois, Marie-Laure; Barrière, Paul; Destrumelle, Sandrine; Vera-Munoz, Oscar; Tainturier, Daniel

    2010-06-01

    Chicken egg yolk is held as an excellent cryoprotective agent for freezing canine semen. Recent advances have enabled the extraction of low density lipoproteins from egg yolk, which are responsible for the cryoprotective abilities of the latter. The objective of this article was to compare 3 semen extenders for freezing canine semen: 2 containing egg yolk (Tris egg yolk and Equex STAMP) and one containing 6% LDL. After freezing and thawing 20 ejaculates from 5 different dogs, the 6% LDL extender produced 50% mobile spermatozoa, compared with 48% with the Equex extender and 27.7% with the extender containing egg yolk alone (EY). In vitro functional tests demonstrated that the integrity of the plasma membrane (hypoosmotic test) was respected in 65-66% of spermatozoa as a function of the extender; DNA integrity was respected in more than 97% of the spermatozoa. The Equex extender provided superior acrosome integrity (FITC/PSA test): 68.4% compared with 55.1% with LDL and 53.3% with egg yolk. However, the 6% LDL extender resulted in fewer spermatozoal anomalies (Spermac test), with 54.6% normal spermatozoa compared to 53.6% for Equex and 53.3% with the egg yolk. All six of the bitches inseminated artificially via the intra-uterine route (Scandinavian technique) using semen frozen in the 6% LDL extender became pregnant. The LDL extender resulted in percentages of mobile spermatozoa and movement characteristics that were as good if not better than those obtained with the reference extenders following thawing. The 6% LDL extender appears to have the same cryoprotective qualities as the reference diluent, Equex STAMP. PMID:20153943

  11. Punicalagin Induces Serum Low-Density Lipoprotein Influx to Macrophages.

    PubMed

    Atrahimovich, Dana; Khatib, Soliman; Sela, Shifra; Vaya, Jacob; Samson, Abraham O

    2016-01-01

    High levels of circulating low-density lipoprotein (LDL) are a primary initiating event in the development of atherosclerosis. Recently, the antiatherogenic effect of polyphenols has been shown to be exerted via a mechanism unrelated to their antioxidant capacity and to stem from their interaction with specific intracellular or plasma proteins. In this study, we investigated the interaction of the main polyphenol in pomegranate, punicalagin, with apolipoprotein B-100 (ApoB100) that surrounds LDL. Punicalagin bound to ApoB100 at low concentrations (0.25-4 μM). Upon binding, it induced LDL influx to macrophages in a concentration-dependent manner, up to 2.5-fold. In contrast, another polyphenol which binds to ApoB100, glabridin, did not affect LDL influx. We further showed that LDL influx occurs specifically through the LDL receptor, with LDL then accumulating in the cell cytoplasm. Taken together with the findings of Aviram et al., 2000, that pomegranate juice and punicalagin induce plasma LDL removal and inhibit macrophage cholesterol synthesis and accumulation, our results suggest that, upon binding, punicalagin stimulates LDL influx to macrophages, thus reducing circulating cholesterol levels. PMID:27516832

  12. Punicalagin Induces Serum Low-Density Lipoprotein Influx to Macrophages

    PubMed Central

    Atrahimovich, Dana; Khatib, Soliman; Sela, Shifra; Vaya, Jacob

    2016-01-01

    High levels of circulating low-density lipoprotein (LDL) are a primary initiating event in the development of atherosclerosis. Recently, the antiatherogenic effect of polyphenols has been shown to be exerted via a mechanism unrelated to their antioxidant capacity and to stem from their interaction with specific intracellular or plasma proteins. In this study, we investigated the interaction of the main polyphenol in pomegranate, punicalagin, with apolipoprotein B-100 (ApoB100) that surrounds LDL. Punicalagin bound to ApoB100 at low concentrations (0.25–4 μM). Upon binding, it induced LDL influx to macrophages in a concentration-dependent manner, up to 2.5-fold. In contrast, another polyphenol which binds to ApoB100, glabridin, did not affect LDL influx. We further showed that LDL influx occurs specifically through the LDL receptor, with LDL then accumulating in the cell cytoplasm. Taken together with the findings of Aviram et al., 2000, that pomegranate juice and punicalagin induce plasma LDL removal and inhibit macrophage cholesterol synthesis and accumulation, our results suggest that, upon binding, punicalagin stimulates LDL influx to macrophages, thus reducing circulating cholesterol levels. PMID:27516832

  13. MiR-590-5p Inhibits Oxidized- LDL Induced Angiogenesis by Targeting LOX-1

    PubMed Central

    Dai, Yao; Zhang, Zhigao; Cao, Yongxiang; Mehta, Jawahar L.; Li, Jun

    2016-01-01

    Oxidized low-density lipoprotein (ox-LDL) is, at least in part, responsible for angiogenesis in atherosclerotic regions. This effect of ox-LDL has been shown to be mediated through a specific receptor LOX-1. Here we describe the effect of miR-590-5p on ox-LDL-mediated angiogenesis in in vitro and in vivo settings. Human umbilical vein endothelial cells (HUVECs) were transfected with miR-590-5p mimic or inhibitor followed by treatment with ox-LDL. In other experiments, Marigel plugs were inserted in the mice subcutaneous space. Both in vitro and in vivo studies showed that miR-590-5p mimic (100 nM) inhibited the ox-LDL-mediated angiogenesis (capillary tube formation, cell proliferation and migration as well as pro-angiogenic signals- ROS, MAPKs, pro-inflammatory cytokines and adhesion-related proteins). Of note, miR-590-5p inhibitor (200 nM) had the opposite effects. The inhibitory effect of miR-590-5p on angiogenesis was mediated by inhibition of LOX-1 at translational level. The inhibition of LOX-1 by miR-590-5p was confirmed by luciferase assay. In conclusion, we show that MiR-590-5p inhibits angiogenesis by targeting LOX-1 and suppressing redox-sensitive signals. PMID:26932825

  14. MiR-590-5p Inhibits Oxidized- LDL Induced Angiogenesis by Targeting LOX-1.

    PubMed

    Dai, Yao; Zhang, Zhigao; Cao, Yongxiang; Mehta, Jawahar L; Li, Jun

    2016-01-01

    Oxidized low-density lipoprotein (ox-LDL) is, at least in part, responsible for angiogenesis in atherosclerotic regions. This effect of ox-LDL has been shown to be mediated through a specific receptor LOX-1. Here we describe the effect of miR-590-5p on ox-LDL-mediated angiogenesis in in vitro and in vivo settings. Human umbilical vein endothelial cells (HUVECs) were transfected with miR-590-5p mimic or inhibitor followed by treatment with ox-LDL. In other experiments, Marigel plugs were inserted in the mice subcutaneous space. Both in vitro and in vivo studies showed that miR-590-5p mimic (100 nM) inhibited the ox-LDL-mediated angiogenesis (capillary tube formation, cell proliferation and migration as well as pro-angiogenic signals- ROS, MAPKs, pro-inflammatory cytokines and adhesion-related proteins). Of note, miR-590-5p inhibitor (200 nM) had the opposite effects. The inhibitory effect of miR-590-5p on angiogenesis was mediated by inhibition of LOX-1 at translational level. The inhibition of LOX-1 by miR-590-5p was confirmed by luciferase assay. In conclusion, we show that MiR-590-5p inhibits angiogenesis by targeting LOX-1 and suppressing redox-sensitive signals. PMID:26932825

  15. Oxidized LDL Is Strictly Limited to Hyperthyroidism Irrespective of Fat Feeding in Female Sprague Dawley Rats.

    PubMed

    Zelzer, Sieglinde; Mangge, Harald; Pailer, Sabine; Ainoedhofer, Herwig; Kieslinger, Petra; Stojakovic, Tatjana; Scharnagl, Hubert; Prüller, Florian; Weghuber, Daniel; Datz, Christian; Haybaeck, Johannes; Obermayer-Pietsch, Barbara; Trummer, Christian; Gostner, Johanna; Gruber, Hans-Jürgen

    2015-01-01

    Metabolic dysfunctions might play a crucial role in the pathophysiology of thyroid dysfunctions. This study aimed to investigate the impact of a controlled diet (normal versus high fat feeding) on hypothyroid and hyperthyroid Sprague Dawley rats. Female Sprague Dawley rats (n = 66) were grouped into normal diet (n = 30) and high-fat diet (n = 36) groups and subdivided into controls, hypothyroid and hyperthyroid groups, induced through propylthiouracil or triiodothyronine (T3) treatment, respectively. After 12 weeks of treatment metabolic parameters, such as oxidized LDL (oxLDL), malondialdehyde (MDA), 4-hydroxynonenal (HNE), the lipid profile, body weight and food intake parameters were analyzed. Successfully induced thyroid dysfunctions were shown by T3 levels, both under normal and high fat diet. Thyroid dysfunctions were accompanied by changes in calorie intake and body weight as well as in the lipid profile. In detail, hypothyroid rats showed significantly decreased oxLDL levels, whereas hyperthyroid rats showed significantly increased oxLDL levels. These effects were seen under high fat diet and were less pronounced with normal feeding. Taken together, we showed for the first time in female SD rats that only hyper-, but not hypothyroidism, is associated with high atherogenic oxidized LDL irrespective of normal or high-fat diet in Sprague Dawley rats. PMID:26006242

  16. Oxidized LDL Is Strictly Limited to Hyperthyroidism Irrespective of Fat Feeding in Female Sprague Dawley Rats

    PubMed Central

    Zelzer, Sieglinde; Mangge, Harald; Pailer, Sabine; Ainoedhofer, Herwig; Kieslinger, Petra; Stojakovic, Tatjana; Scharnagl, Hubert; Prüller, Florian; Weghuber, Daniel; Datz, Christian; Haybaeck, Johannes; Obermayer-Pietsch, Barbara; Trummer, Christian; Gostner, Johanna; Gruber, Hans-Jürgen

    2015-01-01

    Metabolic dysfunctions might play a crucial role in the pathophysiology of thyroid dysfunctions. This study aimed to investigate the impact of a controlled diet (normal versus high fat feeding) on hypothyroid and hyperthyroid Sprague Dawley rats. Female Sprague Dawley rats (n = 66) were grouped into normal diet (n = 30) and high-fat diet (n = 36) groups and subdivided into controls, hypothyroid and hyperthyroid groups, induced through propylthiouracil or triiodothyronine (T3) treatment, respectively. After 12 weeks of treatment metabolic parameters, such as oxidized LDL (oxLDL), malondialdehyde (MDA), 4-hydroxynonenal (HNE), the lipid profile, body weight and food intake parameters were analyzed. Successfully induced thyroid dysfunctions were shown by T3 levels, both under normal and high fat diet. Thyroid dysfunctions were accompanied by changes in calorie intake and body weight as well as in the lipid profile. In detail, hypothyroid rats showed significantly decreased oxLDL levels, whereas hyperthyroid rats showed significantly increased oxLDL levels. These effects were seen under high fat diet and were less pronounced with normal feeding. Taken together, we showed for the first time in female SD rats that only hyper-, but not hypothyroidism, is associated with high atherogenic oxidized LDL irrespective of normal or high-fat diet in Sprague Dawley rats. PMID:26006242

  17. Resolving Low-Density Lipoprotein (LDL) on the Human Aortic Surface Using Large Eddy Simulation

    NASA Astrophysics Data System (ADS)

    Lantz, Jonas; Karlsson, Matts

    2011-11-01

    The prediction and understanding of the genesis of vascular diseases is one of the grand challenges in biofluid engineering. The progression of atherosclerosis is correlated to the build- up of LDL on the arterial surface, which is affected by the blood flow. A multi-physics simulation of LDL mass transport in the blood and through the arterial wall of a subject specific human aorta was performed, employing a LES turbulence model to resolve the turbulent flow. Geometry and velocity measurements from magnetic resonance imaging (MRI) were incorporated to assure physiological relevance of the simulation. Due to the turbulent nature of the flow, consecutive cardiac cycles are not identical, neither in vivo nor in the simulations. A phase average based on a large number of cardiac cycles is therefore computed, which is the proper way to get reliable statistical results from a LES simulation. In total, 50 cardiac cycles were simulated, yielding over 2.5 Billion data points to be post-processed. An inverse relation between LDL and WSS was found; LDL accumulated on locations where WSS was low and vice-versa. Large temporal differences were present, with the concentration level decreasing during systolic acceleration and increasing during the deceleration phase. This method makes it possible to resolve the localization of LDL accumulation in the normal human aorta with its complex transitional flow.

  18. Unmet Needs in LDL-C Lowering: When Statins Won't Do!

    PubMed

    Krähenbühl, Stephan; Pavik-Mezzour, Ivana; von Eckardstein, Arnold

    2016-08-01

    The use of low-density lipoprotein cholesterol (LDL-C)-lowering medications has led to a significant reduction of cardiovascular risk in both primary and secondary prevention. Statin therapy, one of the cornerstones for the prevention and treatment of cardiovascular disease (CVD), has been demonstrated to be effective in lowering LDL-C levels and in reducing the risk for CVD and is generally well-tolerated. However, compliance with statins remains suboptimal. One of the main reasons is limitations by adverse events, notably myopathies, which can lead to non-compliance with the prescribed statin regimen. Reducing the burden of elevated LDL-C levels is critical in patients with CVD as well as in patients with very high baseline levels of LDL-C (e.g. patients with familial hypercholesterolaemia), as statin therapy is insufficient for optimally reducing LDL-C below target values. In this review, we discuss alternative treatment options after maximally tolerated doses of statin therapy, including ezetimibe, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, and cholesteryl ester transfer protein (CETP) inhibitors. Difficult-to-treat patients may benefit from combination therapy with ezetimibe or a PCSK9 inhibitor (evolocumab or alirocumab, which are now available). Updates of treatment guidelines are needed to guide the management of patients who will best benefit from these new treatments. PMID:27456066

  19. Anti-bis(monoacylglycero)phosphate antibody accumulates acetylated LDL-derived cholesterol in cultured macrophages.

    PubMed

    Delton-Vandenbroucke, Isabelle; Bouvier, Jerome; Makino, Asami; Besson, Nelly; Pageaux, Jean-François; Lagarde, Michel; Kobayashi, Toshihide

    2007-03-01

    Bis(monoacylglycero)phosphate (BMP), also called lysobisphosphatidic acid, is a phospholipid highly enriched in the internal membranes of multivesicular late endosomes, in which it forms specialized lipid domains. It has been suggested that BMP-rich membranes regulate cholesterol transport. Here, we examine the effects of an anti-BMP antibody on cholesterol metabolism and transport in two macrophage cell lines, RAW 264.7 and THP-1, during loading with acetylated low density lipoprotein (AcLDL). Anti-BMP antibody was internalized and accumulated in both macrophage cell types. Cholesterol staining with filipin and mass measurements indicate that AcLDL-stimulated accumulation of free cholesterol (FC) was enhanced in macrophages that had accumulated the antibody. Unlike the hydrophobic amine U18666A (3-beta-[2-(diethylamino)ethoxy]androst-5-en-17-one), esterification of AcLDL-derived cholesterol by ACAT was not modified after anti-BMP treatment. AcLDL loading led to an increase of FC in the plasma membrane. This increase was further enhanced in anti-BMP-treated macrophages. However, cholesterol efflux to HDL was reduced in antibody-treated cells. These results suggest that the accumulation of anti-BMP antibody alters cholesterol homeostasis in AcLDL-loaded macrophages. PMID:17146116

  20. The role of mitosis in LDL transport through cultured endothelial cell monolayers

    PubMed Central

    Cancel, Limary M.

    2011-01-01

    We (7) have previously shown that leaky junctions associated with dying or dividing cells are the dominant pathway for LDL transport under convective conditions, accounting for >90% of the transport. We (8) have also recently shown that the permeability of bovine aortic endothelial cell monolayers is highly correlated with their rate of apoptosis and that inhibiting apoptosis lowers the permeability of the monolayers to LDL. To explore the role of mitosis in the leaky junction pathway, the microtubule-stabilizing agent paclitaxel was used to alter the rate of mitosis, and LDL flux and water flux (Jv) were measured. Control monolayers had an average mitosis rate of 0.029%. Treatment with paclitaxel (2.5 μM) for 1.5, 3, 4.5, or 6 h yielded increasing rates of mitosis ranging from 0.099% to 1.03%. The convective permeability of LDL (Pe) increased up to fivefold, whereas Jv increased up to threefold, over this range of mitosis rates. We found strong correlations between the mitosis rate and both Pe and Jv. However, compared with our previous apoptosis study (8), we found that mitosis was only half as effective as apoptosis in increasing Pe. The results led us to conclude that while mitotsis-related leaky junctions might play a role in the initial infiltration of LDL into the artery wall, the progression of atherosclerosis might be more closely correlated with apoptosis-related leaky junctions. PMID:21169397

  1. The relationship between oxidised LDL, endothelial progenitor cells and coronary endothelial function in patients with CHD

    PubMed Central

    Watt, Jonathan; Kennedy, Simon; Ahmed, Nadeem; Hayhurst, James; McClure, John D; Berry, Colin; Wadsworth, Roger M; Oldroyd, Keith G

    2016-01-01

    Objective The balance between coronary endothelial dysfunction and repair is influenced by many protective and deleterious factors circulating in the blood. We studied the relationship between oxidised low-density lipoprotein (oxLDL), circulating endothelial progenitor cells (EPCs) and coronary endothelial function in patients with stable coronary heart disease (CHD). Methods 33 patients with stable CHD were studied. Plasma oxLDL was measured using ELISA, coronary endothelial function was assessed using intracoronary acetylcholine infusion and EPCs were quantified using flow cytometry for CD34+/KDR+ cells. Results Plasma oxLDL correlated positively with the number of EPCs in the blood (r=0.46, p=0.02). There was a positive correlation between the number of circulating EPCs and coronary endothelial function (r=0.42, p=0.04). There was no significant correlation between oxLDL and coronary endothelial function. Conclusions Plasma levels of oxLDL are associated with increased circulating EPCs in the blood of patients with CHD, which may reflect a host-repair response to endothelial injury. Patients with stable CHD had a high prevalence of coronary endothelial dysfunction, which was associated with lower numbers of circulating EPCs, suggesting a mechanistic link between endothelial dysfunction and the pathogenesis of atherosclerosis. PMID:26848395

  2. Increased Small Dense LDL and Intermediate-Density Lipoprotein With Albuminuria in Type 1 Diabetes

    PubMed Central

    Sibley, Shalamar D.; Hokanson, John E.; Steffes, Michael W.; Purnell, Jonathan Q; Marcovina, Santica M.; Cleary, Patricia A.; Brunzell, John D.

    2009-01-01

    OBJECTIVE This population study examines the relationship between LDL density and persistent albuminuria in subjects with type 1 diabetes at the end of the Diabetes Control and Complications Trial (DCCT). RESEARCH DESIGN AND METHODS Subjects were classified as persistently normoalbuminuric (albumin excretion rate [AER] <30 mg/d, n = 1,056), microalbuminuric (AER ≥30–299 mg/day, n = 80), and macroalbuminuric (AER = 300 mg/day, n = 24) based on the last two AER measures. RESULTS Triglyceride (P <0.01) and LDL cholesterol (P <0.01) levels were higher in macroalbuminuric subjects compared with normoalbuminuric subjects. Cholesterol distribution by density-gradient ultracentrifugation showed an increase in intermediate-density lipoprotein (IDL) and a shift in peak LDL from buoyant toward more dense particles with progressive albuminuria. In the entire group, there was a significant negative correlation between the peak buoyancy of LDL particles and albuminuria (r = −0.238, P <0.001, n = 1,160). This correlation persisted in the normoalbuminuric DCCT group (r = −0.138, P<0.001, n = 1,056). CONCLUSIONS As albuminuria increases in subjects with type 1 diabetes, dyslipidemia occurs with an increase in IDL and dense LDL that may lead to increased cardiovascular disease. PMID:10388983

  3. Jeremiah Metzger Lecture: Cholesterol, Inflammation and Atherosclerotic Cardiovascular Disease: Is It All LDL?

    PubMed Central

    Gotto, Antonio M.

    2011-01-01

    Scientific investigation of the relationship between atherosclerosis, inflammation, and lipoprotein metabolism originated in the mid-19th century and has increased exponentially over the past 50 years. Basic research that characterized the lipoproteins and their metabolism was followed by clinical and epidemiologic studies that began to link elevated levels of cholesterol in the blood to the development of atherosclerosis and increased risk for cardiovascular disease. The link between elevated serum cholesterol levels and cardiovascular disease, known as the “lipid hypothesis,” was confirmed with the discoveries of the low-density lipoprotein (LDL) receptor and of the statins. Subsequent results of multiple clinical trials, particularly with statins, have established that reductions in LDL cholesterol are associated with reduced risk for coronary heart disease (CHD). A growing body of evidence suggests that measures of inflammation, such as C-reactive protein (CRP), may enhance cardiovascular risk assessment and help guide clinical decision-making. Reductions in CRP in individuals with low serum levels of LDL cholesterol have been shown to reduce cardiovascular events. A variety of agents designed to further reduce LDL cholesterol, increase high-density lipoprotein (HDL) cholesterol, and target inflammation are currently in development. Future research can help clarify the roles of emerging biomarkers and lipid fractions other than LDL cholesterol in the prevention, diagnosis, and treatment of cardiovascular disease. PMID:21686232

  4. LDL cholesterol goals in high-risk patients: how low do we go and how do we get there?

    PubMed

    Besseling, Joost; van Capelleveen, Julian; Kastelein, John J P; Hovingh, G Kees

    2013-03-01

    It is widely recognised that low-density lipoprotein cholesterol (LDL-C) is one of the most important and modifiable risk factors for cardiovascular disease (CVD). Statins (HMG-CoA reductase inhibitors) have consistently been shown to decrease both LDL-C and CVD risk in almost all patient categories, with the exception of heart and kidney failure as well as advanced aortic stenosis. As a consequence, statins have become the cornerstone in current prevention guidelines. In patients who do not reach the LDL-C target, combination therapy with additional LDL-C lowering drugs (e.g. ezetimibe, bile acid sequestrants or fibrates) should be considered. Guidelines provide different LDL-C levels to strive for, depending on the CVD risk. In this review, we describe the rationale for these LDL-C targets and how these goals might be reached by current and future therapies. PMID:23494186

  5. Electronegative LDL is linked to high-fat, high-cholesterol diet-induced nonalcoholic steatohepatitis in hamsters.

    PubMed

    Lai, Yu-Sheng; Yang, Tzu-Ching; Chang, Po-Yuan; Chang, Shwu-Fen; Ho, Shu-Li; Chen, Hui-Ling; Lu, Shao-Chun

    2016-04-01

    The pathogenesis of nonalcoholic steatohepatitis (NASH), like that of atherosclerosis, involves lipid accumulation, inflammation and fibrosis. Recent studies suggest that oxidized LDL (oxLDL) may be a risk factor for NASH, but oxLDL levels were not directly measured in these studies. The aim of this study was to examine whether there was an association between electronegative LDL [LDL(-)], a mildly oxLDL found in the blood, and the development of NASH using two animal models. Golden Syrian hamsters and C57BL/6 mice were fed a high-fat, high-cholesterol (HFC) diet for 6 or 12weeks, then liver lipid and histopathology, plasma lipoprotein profile and LDL(-) levels were examined. The HFC-diet-fed hamsters and mice had similar levels of hepatic lipid but different histopathological changes, with microvesicular steatosis, hepatocellular hypertrophy, inflammation and bridging fibrosis in the hamsters, but only in mild steatohepatitis with low inflammatory cell infiltration in the mice. It also resulted in a significant increase in plasma levels of LDL cholesterol and LDL(-) in hamsters, but only a slight increase in mice. Moreover, enlarged Kupffer cells, LDL(-) and accumulation of unesterified cholesterol were detected in the portal area of HFC-diet-fed hamsters, but not HFC-diet-fed mice. An in vitro study showed that LDL(-) from HFC-diet-fed hamsters induced TNF-α secretion in rat Kupffer cell through a LOX-1-dependent pathway. Our results strongly suggest that LDL(-) is one of the underlying causes of hepatic inflammation and plays a critical role in the development of NASH. PMID:27012620

  6. The Oxidative State of LDL is the Major Determinant of Anti/Prooxidant Effect of Coffee on Cu Catalysed Peroxidation.

    PubMed

    Carru, Ciriaco; Pasciu, Valeria; Sotgia, Salvatore; Zinellu, Angelo; Nicoli, Maria Cristina; Deiana, Luca; Tadolini, Bruna; Sanna, Bastiano; Masala, Bruno; Pintus, Gianfranco

    2011-01-01

    Antioxidants exert contrasting effect on low density lipoprotein (LDL) oxidation catalysed by metals, acting as pro-oxidants under select in vitro conditions. Through our study on the effect of coffee on LDL oxidation, we identified the parameters governing this phenomenon, contributing to the comprehension of its mechanism and discovering significant implications for correct alimentary recommendations. By measuring conjugated diene formation, we have analysed the quantitative and qualitative effects exerted by an extract of roasted coffee on LDL oxidation triggered by copper sulphate. When the relative effects of different coffee concentrations were plotted against the lag time (LT) of control LDL (C-LDL), the apparently random experimental data arranged in sensible patterns: by increasing the LT the antioxidant activity of coffee decreased progressively to become prooxidant. The critical LT, at which coffee switches from antioxidant to prooxidant, increased by increasing coffee concentration. Also the contrasting results obtained following a delayed addition of coffee to the assay, arranged in a simple pattern when referred to the LT of C-LDL: the prooxidant effect decreased to become antioxidant as the LT of C-LDL increased. The dependence of coffee effect on the LT of C-LDL was influenced by LDL but not by metal catalyst concentration. These novel findings point to the oxidative state of LDL as a major parameter controlling the anti/prooxidant effect of coffee and suggest the LT of C-LDL as a potent analytical tool to express experimental data when studying the action exerted by a compound on LDL oxidation. PMID:21633665

  7. [LDL cholesterol control in patients with very high cardiovascular risk. A simplified algorithm for achieving LDL cholesterol goals "in two steps"].

    PubMed

    Guijarro-Herraiz, Carlos; Masana-Marin, Luis; Galve, Enrique; Cordero-Fort, Alberto

    2014-01-01

    Reducing low density lipoprotein-cholesterol (LDL-c) is the main lipid goal of treatment for patients with very high cardiovascular risk. In these patients the therapeutic goal is to achieve a LDL-c lower than 70 mg/dL, as recommended by the guidelines for cardiovascular prevention commonly used in Spain and Europe. However, the degree of achieving these objectives in this group of patients is very low. This article describes the prevalence of the problem and the causes that motivate it. Recommendations and tools that can facilitate the design of an optimal treatment strategy for achieving the goals are also given. In addition, a new tool with a simple algorithm that can allow these very high risk patients to achieve the goals "in two-steps", i.e., with only two doctor check-ups, is presented. PMID:25048471

  8. Data related to inflammation and cholesterol deposition triggered by macrophages exposition to modified LDL.

    PubMed

    Toledo, Juan; Esteve, Montserrat; Grasa, Mar; Ledda, Angelo; Garda, Horacio; Gulfo, José; Ludovico, Ivo Díaz; Ramella, Nahuel; Gonzalez, Marina

    2016-09-01

    This article supports experimental evidence on the time-dependent effect on gene expression related to inflammation and cholesterol deposition in lipid-loaded cells. The cells employed were human monocytes THP1 line transformed into macrophages by treatment with phorbol esters. Macrophages were treated at different times with oxidized low density lipoprotein (Ox-LDL) and then gene expression was measured. We also include data about the different types of oxidized lipoprotein obtained (low, media or high oxidation) for differential exposure with Cu ions. These data include characterization to lipid and protein peroxidative damage and also quantification of cell viability by exposure to native and modified LDL. The present article complements data published in "Decreased OxLDL uptake and cholesterol efflux in THP1 cells elicited by cortisol and by cortisone through 11β-hydroxysteroid dehydrogenase type 1" Ledda et al. (in press) [1]. PMID:27331097

  9. Imaging and force measurement of LDL and HDL by AFM in air and liquid

    PubMed Central

    Gan, Chaoye; Ao, Meiying; Liu, Zhanghua; Chen, Yong

    2015-01-01

    The size and biomechanical properties of lipoproteins are tightly correlated with their structures/functions. While atomic force microscopy (AFM) has been used to image lipoproteins the force measurement of these nano-sized particles is missing. We detected that the sizes of LDL and HDL in liquid are close to the commonly known values. The Young’s modulus of LDL or HDL is ∼0.4 GPa which is similar to that of some viral capsids or nanovesicles but greatly larger than that of various liposomes. The adhesive force of LDL or HDL is small (∼200 pN). The comparison of AFM detection in air and liquid was also performed which is currently lacking. Our data may provide useful information for better understanding and AFM detection of lipoproteins. PMID:25893163

  10. The neutral sphingomyelinase-2 is involved in angiogenic signaling triggered by oxidized LDL.

    PubMed

    Camaré, Caroline; Augé, Nathalie; Pucelle, Mélanie; Saint-Lebes, Bertrand; Grazide, Marie-Hélène; Nègre-Salvayre, Anne; Salvayre, Robert

    2016-04-01

    Capillaries of the external part of the normal arterial wall constitute the vasa vasorum network. In atherosclerotic lesions, neovascularization occurs in areas of intimal hyperplasia where it may promote plaque expansion, and intraplaque hemorrhage. Oxidized LDL that are present in atherosclerotic areas activate various angiogenic signaling pathways, including reactive oxygen species and the sphingosine kinase/sphingosine-1-phosphate pathway. We aimed to investigate whether oxidized LDL-induced angiogenesis requires neutral sphingomyelinase-2 activation and the neutral sphingomyelinase-2/sphingosine kinase-1 pathway. The role of neutral sphingomyelinase-2 in angiogenic signaling was investigated in Human Microvascular Endothelial Cells (HMEC-1) forming capillary tube on Matrigel and in vivo in the Matrigel plug assay in C57BL/6 mice and in the chicken chorioallantoic membrane model. Low concentration of human oxidized LDL elicits HMEC-1 capillary tube formation and neutral sphingomyelinase-2 activation, which were blocked by neutral sphingomyelinase-2 inhibitors, GW4869 and specific siRNA. This angiogenic effect was mimicked by low concentration of C6-Ceramide and was inhibited by sphingosine kinase-1 inhibitors. Upstream of neutral sphingomyelinase-2, oxidized LDL-induced activation required LOX-1, reactive oxygen species generation by NADPH oxidase and p38-MAPK activation. Inhibition of sphingosine kinase-1 blocked the angiogenic response and triggered HMEC-1 apoptosis. Low concentration of oxidized LDL was angiogenic in vivo, both in the Matrigel plug assay in mice and in the chorioallantoic membrane model, and was blocked by GW4869. In conclusion, low oxLDL concentration triggers sprouting angiogenesis that involves ROS-induced activation of the neutral sphingomyelinase-2/sphingosine kinase-1 pathway, and is effectively inhibited by GW4869. PMID:26855418

  11. Alginate oligosaccharide enhances LDL uptake via regulation of LDLR and PCSK9 expression.

    PubMed

    Yang, Ji Hye; Bang, Mi Ae; Jang, Chang Ho; Jo, Gyung Hyun; Jung, Seoung Ki; Ki, Sung Hwan

    2015-11-01

    The hepatic low-density lipoprotein (LDL) receptor (LDLR) plays a crucial role in lipoprotein metabolism by lowering the plasma LDL-cholesterol concentration, which reduces the risk for cardiovascular diseases. Although alginate oligosaccharide (AOS), prepared from degradation, has several pharmacological effects, it is not known whether AOS affects lipoprotein metabolism. This study was conducted to investigate whether AOS up-regulated LDLR expression and LDL uptake in vitro and in vivo, and the underlying molecular mechanism. We found that AOS increased LDLR expression and intracellular uptake of LDL by hepatocytes in a dose- and time-dependent manner. It is well established that sterol-responsive element binding protein-2 (SREBP-2) is an essential transcription factor for LDLR gene expression. AOS enhanced SREBP-2 nuclear translocation and mRNA levels. The specific role of SREBP-2 activation in AOS-induced LDLR expression was verified using an LDLR promoter construct with a sterol response element deletion. The activation of SREBP-2 by AOS is mediated by phosphatidylinositol 3-kinase/Akt/glycogen synthase kinase 3β pathways. Furthermore, we found that expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), a crucial modulator of LDLR, was down-regulated by AOS; this related to the inhibition of hepatocyte nuclear factor-1α. Treatment of mice with AOS for 2 weeks stimulated LDLR expression and reduced PCSK9 expression, resulting in decreased plasma LDL-cholesterol levels. We conclude that AOS lowered plasma LDL-cholesterol levels through regulation LDLR expression. This effect was dependent on SREBP-2 and PCSK9. PMID:26320675

  12. [Update of planning tables of cholesterol-lowering therapy orientated to achieve LDL therapeutic targets].

    PubMed

    Masana, Luis; Plana, Núria

    2015-01-01

    This is the third update of a planning-table for use in cholesterol-lowering therapy, so as to obtain LDLc objectives. This is an easy to use laptop tool to help choose the best statin or combination therapy (statin plus ezetimibe) depending on the current LDL concentration of the patient, and the LDLc objective to achieve. It is based on a colour code that indicates the drugs that are efficient enough to help patients to achieve their LDL goal. Along with the table, recommendations are given for the best strategy in order to implement the optimal therapy in a maximum of two clinical encounters. PMID:25865752

  13. Iron overload diminishes atherosclerosis in apoE-deficient mice

    PubMed Central

    Kirk, Elizabeth A.; Heinecke, Jay W.; LeBoeuf, Renée C.

    2001-01-01

    It has been proposed that elevated levels of tissue iron increase the risk for atherosclerosis, perhaps by favoring the formation of pro-atherogenic oxidized LDL. Working with apoE-deficient (apoE–/–) mice, which do not require a high-fat diet to develop atherosclerosis, we compared the effects of standard diet (0.02% iron) or a 2% carbonyl iron diet. After 24 weeks, mice fed the 2% carbonyl iron diet had twice as much iron in their plasma, a ninefold increase in bleomycin-detectable free iron in their plasma, and ten times as much iron in their livers as control mice. Dietary iron overload caused a modest (30%) rise in plasma triglyceride and cholesterol. Nevertheless, this regimen did not exacerbate, but rather reduced the severity of atherosclerosis by 50%, and it failed to elevate hepatic levels of heme oxygenase mRNA, which is induced by many different oxidative insults in vitro. Moreover, hepatic levels of protein-bound dityrosine and ortho-tyrosine, two markers of metal-catalyzed oxidative damage in vitro, failed to rise in iron-overloaded animals. Our observations suggest that elevated serum and tissue levels of iron are not atherogenic in apoE–/– mice. Moreover, they call into question the hypothesis that elevated levels of tissue iron promote LDL oxidation and oxidative stress in vivo. PMID:11413162

  14. PKCδ-IRAK1 axis regulates oxidized LDL-induced IL-1β production in monocytes[S

    PubMed Central

    Tiwari, Rajiv Lochan; Singh, Vishal; Singh, Ankita; Rana, Minakshi; Verma, Anupam; Kothari, Nikhil; Kohli, Monica; Bogra, Jaishri; Dikshit, Madhu; Barthwal, Manoj Kumar

    2014-01-01

    This study examined the role of interleukin (IL)-1 receptor-associated kinase (IRAK) and protein kinase C (PKC) in oxidized LDL (Ox-LDL)-induced monocyte IL-1β production. In THP1 cells, Ox-LDL induced time-dependent secretory IL-1β and IRAK1 activity; IRAK4, IRAK3, and CD36 protein expression; PKCδ-JNK1 phosphorylation; and AP-1 activation. IRAK1/4 siRNA and inhibitor (INH)-attenuated Ox-LDL induced secreted IL-1β and pro-IL-1β mRNA and pro-IL-1β and mature IL-1β protein expression, respectively. Diphenyleneiodonium chloride (NADPH oxidase INH) and N-acetylcysteine (free radical scavenger) attenuated Ox-LDL-induced reactive oxygen species generation, caspase-1 activity, and pro-IL-1β and mature IL-1β expression. Ox-LDL-induced secretory IL-1β production was abrogated in the presence of JNK INH II, Tanshinone IIa, Ro-31-8220, Go6976, Rottlerin, and PKCδ siRNA. PKCδ siRNA attenuated the Ox-LDL-induced increase in IRAK1 kinase activity, JNK1 phosphorylation, and AP-1 activation. In THP1 macrophages, CD36, toll-like receptor (TLR)2, TLR4, TLR6, and PKCδ siRNA prevented Ox-LDL-induced PKCδ and IRAK1 activation and IL-1β production. Enhanced Ox-LDL and IL-1β in systemic inflammatory response syndrome (SIRS) patient plasma demonstrated positive correlation with each other and with disease severity scores. Ox-LDL-containing plasma induced PKCδ and IRAK1 phosphorylation and IL-1β production in a CD36-, TLR2-, TLR4-, and TLR6-dependent manner in primary human monocytes. Results suggest involvement of CD36, TLR2, TLR4, TLR6, and the PKCδ-IRAK1-JNK1-AP-1 axis in Ox-LDL-induced IL-1β production. PMID:24792928

  15. Small oxidative changes in atherogenic LDL concentrations irreversibly regulate adhesiveness of human endothelial cells: effect of the lazaroid U74500A.

    PubMed

    Colomé, C; Martínez-González, J; Vidal, F; de Castellarnau, C; Badimon, L

    2000-04-01

    The adherence of monocytes to the endothelium is an early event in atherogenesis which is modulated by low density lipoproteins (LDL). We analyzed the effect of atherogenic LDL levels (180 mg cholesterol/dl, for 24 h) with minimal oxidative modifications (thiobarbituric-acid-reactive-substances (TBARS) concentration between 1.2+/-0.1 and 2.5+/-0.3 nmol of malonaldehyde bis-diethyl acetal (MDA) per mg protein) on human umbilical vein endothelial cell (HUVEC) adhesive properties. We used native LDL (n-LDL), and LDL exposed to spontaneous oxidation without antioxidants (mox-LDL) or with 20 micromol/l of the antioxidant butylated hydroxytoluene (BHT-LDL) or 10 micromol/l U74500A (U74500A-LDL), a scavenger of free radicals. Thiobarbituric-acid-reactive-substances (TBARS) levels were significantly higher in mox-LDL (2.5+/-0.3 nmol MDA/mg protein) than in BHT-LDL (1.6+/-0.2), U74500A-LDL (1.2+/-0.1) or in n-LDL (1.3+/-0.1). mox-LDL induced the greatest adhesion of U937 cells to HUVEC (103+/-9% over controls) followed by BHT-LDL (75+/-10%), U74500A-LDL (36+/-9%) and n-LDL (35+/-3%). The lazaroid U74500A efficiently protected U74500A-LDL against oxidative damage and prevented endothelial adhesiveness associated with this LDL modification, inducing adhesion effects similar to those of n-LDL. However, U74500A could not reverse the adhesion induced by previously oxidized LDL (mox-LDL). LDL did not induce the expression of the intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) or E-selectin, but it produced a downregulation of endothelial nitric oxide synthase (NOS III) mRNA levels. Thus, adhesiveness of human endothelial cells (EC) exposed to atherogenic concentrations of LDL is closely modulated by minimal changes in LDL oxidative state, and could be related to a downregulation of NOS III. PMID:10729379

  16. Effect of Endomorphins on HUVECs Treated by ox-LDL and Its Related Mechanisms

    PubMed Central

    Zhao, Juan; Zhang, Qi; Tian, Liming; Huang, Wenhui; Quan, Jinxing; Wang, Jinyang; Xu, Yanjia; Wang, Yunfang; Niu, Ruilan

    2016-01-01

    We found in the present study that treatment with ox-LDL decreased the cell viability and the content of nitric oxide (NO) and the activity of nitric oxide synthase (NOS) as well as eNOS mRNA expression, while increasing the mRNA expression and content of endothelin-1 (ET-1) in human umbilical vein endothelial cells (HUVECs). However, endomorphins EM1/EM2 increased the cell viability and the content of NO and the activity of NOS as well as eNOS mRNA expression, while decreasing the mRNA expression and content of ET-1 compared with ox-LDL alone. Meanwhile, the expressions of JNK and p-JNK were enhanced by ox-LDL while being suppressed by EM1/EM2. The results suggested that EM1 and EM2 can correct the endothelial cell dysfunction induced by ox-LDL and the protective effect may be achieved by affecting the JNK pathway. PMID:27579327

  17. Inflammatory environment and oxidized LDL convert circulating human proangiogenic cells into functional antigen-presenting cells.

    PubMed

    Vinci, Maria Cristina; Piacentini, Luca; Chiesa, Mattia; Saporiti, Federica; Colombo, Gualtiero I; Pesce, Maurizio

    2015-09-01

    The function of human circulating PACs has been described extensively. However, little focus has been placed on understanding how these cells differ in their functions in the presence of microenvironments mimicking vascular inflammation. We hypothesized that exposure to proinflammatory cytokines or the oxLDL, an autoantigen abundant in advanced atherosclerotic plaques, converts PACs into immune-modulating/proinflammatory cells. Hence, we examined the effect of oxLDL and inflammatory stimuli on their phenotype by use of a functional genomics model based on secretome and whole genome transcriptome profiling. PACs obtained from culturing a PBMC fraction in angiogenic medium were primed with DC differentiation cytokines and then exposed to proinflammatory cytokines or oxLDL. Under these conditions, PACs converted into APCs, expressed maturation markers CD80 and CD83, and showed an increased up-regulation of CD86. APCcy and APCox induced a robust T cell BrdU incorporation. Despite a similar ability to induce lymphocyte proliferation, APCcy and APCox differed for the secretory pathway and mRNA expression. Analysis of the differentially expressed genes identified 4 gene "clusters," showing reciprocal modulation in APCcy vs. APCox, justifying, according to functional genomics analyses, a different putative function of the cells in antigen processing. Together, these data show that treatment with inflammatory cytokines or oxLDL converts human PAC phenotypes and functions into that of APCs with similar lymphocyte-activating ability but distinct maturation degree and paracrine functions. PMID:25990243

  18. Radiolabeled cholesteryl ethers trace LDL cholesteryl esters but not HDL cholesteryl esters in the rat.

    PubMed

    Terpstra, A H

    1995-01-01

    The intravascular metabolism of cholesteryl [1-14C]oleoyl ester and [1,2-3H(N)]cholesteryl palmityl ether was compared in the rat, an animal species without plasma cholesteryl ester transfer activity (CETA). The tracers had identical plasma disappearance rates when they were incorporated into human or rat low density lipoproteins (LDL). Fractional catabolic rates (FCR) were 0.081 +/- 0.014 h-1 and 0.080 +/- 0.013 h-1 for human LDL ester and ether and 0.098 +/- 0.007 h-1 and 0.101 +/- 0.007 h-1 for rat LDL ester and ether, respectively. In contrast, the ether had plasma disappearance rates that were 24%-25% lower than the ester when they were incorporated into human or rat high density lipoproteins (HDL). FCR were 0.230 +/- 0.020 and 0.173 +/- 0.030 h-1 for human HDL ester and ether and 0.131 +/- 0.020 h-1 and 0.100 +/- 0.017 h-1 for rat HDL ester and ether respectively. Biological screening of the rat HDL preparations did not affect these differences. The results of these studies indicate that in the absence of plasma CETA, cholesteryl ethers can be used to trace LDL cholesteryl esters but not to trace HDL cholesteryl esters. PMID:7772060

  19. Expression of lectin-like oxidized LDL receptor-1 in smooth muscle cells after vascular injury

    SciTech Connect

    Eto, Hideyuki; Miyata, Masaaki . E-mail: miyatam@m3.kufm.kagoshima-u.ac.jp; Kume, Noriaki; Minami, Manabu; Itabe, Hiroyuki; Orihara, Koji; Hamasaki, Shuichi; Biro, Sadatoshi; Otsuji, Yutaka; Kita, Toru; Tei, Chuwa

    2006-03-10

    Lectin-like oxidized LDL receptor-1 (LOX-1) is an oxidized LDL receptor, and its role in restenosis after angioplasty remains unknown. We used a balloon-injury model of rabbit aorta, and reverse transcription-polymerase chain reaction revealed that LOX-1 mRNA expression was modest in the non-injured aorta, reached a peak level 2 days after injury, and remained elevated until 24 weeks after injury. Immunohistochemistry and in situ hybridization showed that LOX-1 was not detected in the media of non-injured aorta but expressed in both medial and neointimal smooth muscle cells (SMC) at 2 and 24 weeks after injury. Low concentrations of ox-LDL (10 {mu}g/mL) stimulated the cultured SMC proliferation, which was inhibited by antisense oligonucleotides of LOX-1 mRNA. Double immunofluorescense staining showed the colocalization of LOX-1 and proliferating cell nuclear antigen in human restenotic lesion. These results suggest that LOX-1 mediates ox-LDL-induced SMC proliferation and plays a role in neointimal formation after vascular injury.

  20. The Role of Calcium in Lipoprotein Release by the LDL Receptor†

    PubMed Central

    Zhao, Zhenze; Michaely, Peter

    2009-01-01

    The LDL receptor (LDLR) mediates efficient endocytosis of VLDL, VLDL remnants and LDL. As part of the uptake process, the LDLR releases lipoproteins in endosomes. Released lipoproteins are subsequently trafficked to lysosomes for degradation, while the LDLR recycles back to the cell surface for further rounds of uptake. Endosomes have at least two features that can promote lipoprotein release: an acidic pH and low concentrations of free calcium. The relative contributions of acidic pH and low free calcium to lipoprotein release are not known. Here, we generated fibroblasts that express either normal LDLR or an LDLR variant that is unable to employ the acid-dependent release mechanism to determine the relative contributions of acidic pH and low free calcium on lipoprotein release. We show that endosomal concentrations of free calcium can drive lipoprotein release at rates that are similar to those of acid-dependent release and that the calcium-dependent and acid-dependent mechanisms can cooperate during lipoprotein release. Assessment of lipoprotein uptake by these two cell lines showed that LDL uptake requires the acid-dependent mechanism, while uptake of the VLDL remnant, β-VLDL, does not. We propose that endosomes use both the acid-dependent and calcium-dependent release mechanisms to drive lipoprotein release and that the acid-dependent process is only required for LDL release. PMID:19583244

  1. Measurement of LDL-C after treatment with the CETP inhibitor anacetrapib[S

    PubMed Central

    Davidson, Michael; Liu, Sherry Xueyu; Barter, Philip; Brinton, Eliot A.; Cannon, Christopher P.; Gotto, Antonio M.; Leary, Elizabeth T.; Shah, Sukrut; Stepanavage, Michael; Mitchel, Yale; Dansky, Hayes M.

    2013-01-01

    Estimation of low-density lipoprotein cholesterol (LDL-C) using the Friedewald (FR) formula is often inaccurate when triglycerides are elevated or VLDL particle composition is altered. We hypothesized that LDL-C estimation by the FR formula and other measurement methods might also be inaccurate in individuals treated with a cholesteryl ester transfer protein (CETP) inhibitor. An assay comparison study was conducted using pre and posttreatment serum samples from 280 of the 811 patients treated with the CETP inhibitor anacetrapib in the DEFINE study (determining the ef ficacy and tolerability of CETP in hibition with anac e trapib). After 24 weeks of treatment with anacetrapib, mean LDL-C values by FR formula, Roche direct method (RDM) and Genzyme direct method (GDM) deviated from that measured by the β-quantification (BQ) reference method by –12.2 ± 7.5, –10.2 ± 6.6, –10.8 ± 8.8 mg/dl, respectively. After treatment with anacetrapib, the FR formula and detergent-based direct methods provided lower LDL-C values than those obtained by the BQ reference method. The bias by the FR formula appeared to be due to an overestimation of VLDL-C by the TG/5 component of the formula. Evaluation of the clinical significance of these findings awaits comprehensive lipid and cardiovascular outcome data from ongoing Phase III clinical studies of anacetrapib. PMID:23172660

  2. Evidence for a gene influencing fasting LDL cholesterol and triglyceride levels on chromosome 21q.

    PubMed

    North, Kari E; Miller, Michael B; Coon, Hilary; Martin, Lisa J; Peacock, James M; Arnett, Donna; Zhang, Binbin; Province, Michael; Oberman, Albert; Blangero, John; Almasy, Laura; Ellison, R Curtis; Heiss, Gerardo

    2005-03-01

    High levels of low-density lipoprotein (LDL) cholesterol, low levels of high-density lipoprotein (HDL) cholesterol, and high levels of triglycerides (TG) are strong predictors of cardiovascular disease risk. Motivated by previous evidence for pleiotropy between cholesterol and TG levels, we conducted bivariate linkage analysis of LDL cholesterol and TG concentration among participants of the Hypertension Genetic Epidemiolgy Network (HyperGEN), one of four networks in the NHLBI sponsored Family Blood Pressure Program Project. All available hypertensive siblings and their first-degree relatives were recruited. Both phenotypes were similarly adjusted for ethnicity, study center, sex, age, age-by-sex interactions, smoking, alcohol consumption, hormone use, diabetes medication use, and waist circumference. Variance component linkage analysis was performed as implemented in SOLAR, using ethnicity-specific marker allele frequencies derived from founders and multipoint IBDs calculated in MERLIN. A maximum genome-wide empirical LOD score of 3.9 was detected on chromosome 21 at 54cM, between markers D21S2055 and D21S1446. This signal overlaps with suggestive and/or significant linkages for total cholesterol, LDL cholesterol, and apolipoprotein B in three other studies and is suggestive of one or more genes on chromosome 21q jointly regulating LDL cholesterol and TG concentration. PMID:15721017

  3. Percentage of Adults with High Cholesterol Whose LDL Cholesterol Levels Are Adequately Controlled

    MedlinePlus

    ... of Adults with High Cholesterol Whose LDL Cholesterol Levels are Adequately Controlled High cholesterol can double a ... with High Cholesterol that is Controlled by Education Level 8k4c-k22f Download these data » Click on legends ...

  4. Effect of Endomorphins on HUVECs Treated by ox-LDL and Its Related Mechanisms.

    PubMed

    Zhao, Juan; Zhang, Qi; Liu, Jing; Tian, Liming; Huang, Wenhui; Quan, Jinxing; Wang, Jinyang; Xu, Yanjia; Wang, Yunfang; Niu, Ruilan

    2016-01-01

    We found in the present study that treatment with ox-LDL decreased the cell viability and the content of nitric oxide (NO) and the activity of nitric oxide synthase (NOS) as well as eNOS mRNA expression, while increasing the mRNA expression and content of endothelin-1 (ET-1) in human umbilical vein endothelial cells (HUVECs). However, endomorphins EM1/EM2 increased the cell viability and the content of NO and the activity of NOS as well as eNOS mRNA expression, while decreasing the mRNA expression and content of ET-1 compared with ox-LDL alone. Meanwhile, the expressions of JNK and p-JNK were enhanced by ox-LDL while being suppressed by EM1/EM2. The results suggested that EM1 and EM2 can correct the endothelial cell dysfunction induced by ox-LDL and the protective effect may be achieved by affecting the JNK pathway. PMID:27579327

  5. A Numerical Computation Model for Low-Density Lipoprotein (LDL) Aggregation and Deposition in the Human Artery

    NASA Astrophysics Data System (ADS)

    Zhao, Yongli; Cai, Shaobiao; Ratner, Albert

    2009-11-01

    Cholesterol caused cardiovascular events are commonly seen in human lives. These events are primarily believed to be caused by the built up of particles like low-density lipoprotein (LDL). When a large number of LDL circulates in the blood, it can gradually build up in the inner walls of the arteries. A thick, hard deposit plaque can be formed together with other substances. This type of plaque may clog those arteries and cause vascular problems. Clinical evidences suggest that LDL is related to cardiovascular events and the progression of coronary heart disease is due to its aggregation and deposition. This study presents an investigation of LDL aggregation and deposition based on particulate flow. A soft-sphere based particulate computational flow model is developed to represent LDL suspending in plasma. The transport, collision and adhesion phenomena of LDL particles are simulated to examine the physics involved in aggregation and deposition. A multiple-time step discrete-element approach is presented for efficiently simulating large number of LDL particles and their interactions. The roles the quality and quantity the LDL playing in the process of aggregation and deposition are determined. The study provides a new perspective for improving the understanding of the fundamentals as related to these particle-caused cardiovascular events.

  6. Prevention by alpha-tocopherol and rutin of glutathione and ATP depletion induced by oxidized LDL in cultured endothelial cells.

    PubMed Central

    Schmitt, A.; Salvayre, R.; Delchambre, J.; Nègre-Salvayre, A.

    1995-01-01

    1. Oxidized low density lipoproteins (LDL) are thought to play an important role in atherogenesis. Mildly oxidized LDL are cytotoxic to cultured endothelial cells. Toxic doses of oxidized LDL promote the peroxidation of cellular lipids (beginning at 6 h and being maximal after 12 h of pulse with oxidized LDL) and glutathione and ATP depletion (beginning after 15 h of pulse and evolving concurrently with the cytotoxicity). 2. Antioxidants from 3 different classes (rutin, ascorbic acid and alpha-tocopherol) were compared as to their ability to inhibit the cytotoxic effect of oxidized LDL to endothelial cells. 3. Effective concentrations of alpha-tocopherol inhibited cellular lipid peroxidation, glutathione and ATP depletion and the cytotoxic effect. 4. Ascorbic acid was less effective than alpha-tocopherol and rutin, and exhibited a dose-dependent biphasic effect in the presence of oxidized LDL. 5. Effective concentrations of rutin inhibited glutathione and ATP depletion as well as cytotoxicity, but did not block cellular lipid peroxidation. This suggests that the glutathione and ATP depletion is directly correlated to the cytotoxicity of oxidized LDL, whereas cellular lipid peroxidation is probably not directly the cause of cellular damage leading to cell death. 6. The association of antioxidants of 3 different classes allowed the suppression of the biphasic effect of ascorbic acid and increased the efficacy of the protective effect. The potential consequences for prevention of the pathogenic role of oxidized LDL in endothelial injury are discussed. PMID:8640336

  7. LDL particle heterogeneity, and its association with other established cardiovascular risk factors in a young Indian industrial population

    PubMed Central

    Lakshmy, Ramakrishnan; Dorairaj, Prabhakaran; Tarik, Mohamad; Gupta, Ruby; Reddy, Kolli Srinath

    2012-01-01

    Objective Low density lipoprotein (LDL) particles are heterogeneous in terms of size, density, chemical composition and electric charge with certain particle of LDL being more atherogenic than the others. The present study aimed to look at the LDL particle heterogeneity, particle size and association with other cardiovascular disease (CVD) risk factors in young Indian industrial population. Methodology 600 employees of an industry of Delhi, aged 20-39 years were selected for the study. Data on demographics, individual characteristics associated with major risk factors of CVD, past medical history, clinical and anthropometric profile was collected. Fasting glucose, lipid profile, apolipoprotein (A1, B, and E), lipoprotein (a), high sensitive C-reactive protein (hsCRP) and insulin were estimated. LDL particle size was determined in ethylenediamminetetraacetate (EDTA) plasma by 3% polyacrylamide gel electrophoresis. Result We found a prevalence of small dense LDL phenotype (LDL size ≤ 26.3) in 27.4% of males and 24.0% of females. The mean waist circumference, blood pressure, triglycerides (TAG), cholesterol, hsCRP, apolipoprotein (A1, B and E) and insulin were higher in males whereas mean high density lipoprotein was higher in females. Females also had a significantly higher mean LDL particle diameter as compared to males. Conclusion TAG, physical activity and lipoprotein (a) correlated with small dense LDL in this young Indian population.

  8. Age- and Gender-Related Differences in LDL-Cholesterol Management in Outpatients with Type 2 Diabetes Mellitus

    PubMed Central

    Russo, Giuseppina; Pintaudi, Basilio; Giorda, Carlo; Lucisano, Giuseppe; Nicolucci, Antonio; Cristofaro, Maria Rosaria; Suraci, Concetta; Mulas, Maria Franca; Napoli, Angela; Rossi, Maria Chiara; Manicardi, Valeria

    2015-01-01

    Background. Dyslipidemia contribute to the excess of coronary heart disease (CHD) risk observed in women with type 2 diabetes (T2DM). Low density lipoprotein-cholesterol (LDL-C) is the major target for CHD prevention, and T2DM women seem to reach LDL-C targets less frequently than men. Aim. To explore age- and gender-related differences in LDL-C management in a large sample of outpatients with T2DM. Results. Overall, 415.294 patients (45.3% women) from 236 diabetes centers in Italy were included. Women were older and more obese, with longer diabetes duration, higher total-cholesterol, LDL-C, and HDL-C serum levels compared to men (P < 0.0001). Lipid profile was monitored in ~75% of subjects, women being monitored less frequently than men, irrespective of age. More women did not reach the LDL-C target as compared to men, particularly in the subgroup treated with lipid-lowering medications. The between-genders gap in reaching LDL-C targets increased with age and diabetes duration, favouring men in all groups. Conclusions. LDL-C management is worst in women with T2DM, who are monitored and reach targets less frequently than T2DM men. Similarly to men, they do not receive medications despite high LDL-C. These gender discrepancies increase with age and diabetes duration, exposing older women to higher CHD risk. PMID:25873960

  9. Age- and Gender-Related Differences in LDL-Cholesterol Management in Outpatients with Type 2 Diabetes Mellitus.

    PubMed

    Russo, Giuseppina; Pintaudi, Basilio; Giorda, Carlo; Lucisano, Giuseppe; Nicolucci, Antonio; Cristofaro, Maria Rosaria; Suraci, Concetta; Mulas, Maria Franca; Napoli, Angela; Rossi, Maria Chiara; Manicardi, Valeria

    2015-01-01

    Background. Dyslipidemia contribute to the excess of coronary heart disease (CHD) risk observed in women with type 2 diabetes (T2DM). Low density lipoprotein-cholesterol (LDL-C) is the major target for CHD prevention, and T2DM women seem to reach LDL-C targets less frequently than men. Aim. To explore age- and gender-related differences in LDL-C management in a large sample of outpatients with T2DM. Results. Overall, 415.294 patients (45.3% women) from 236 diabetes centers in Italy were included. Women were older and more obese, with longer diabetes duration, higher total-cholesterol, LDL-C, and HDL-C serum levels compared to men (P < 0.0001). Lipid profile was monitored in ~75% of subjects, women being monitored less frequently than men, irrespective of age. More women did not reach the LDL-C target as compared to men, particularly in the subgroup treated with lipid-lowering medications. The between-genders gap in reaching LDL-C targets increased with age and diabetes duration, favouring men in all groups. Conclusions. LDL-C management is worst in women with T2DM, who are monitored and reach targets less frequently than T2DM men. Similarly to men, they do not receive medications despite high LDL-C. These gender discrepancies increase with age and diabetes duration, exposing older women to higher CHD risk. PMID:25873960

  10. Oxidised LDL up-regulate CD36 expression by the Nrf2 pathway in 3T3-L1 preadipocytes.

    PubMed

    D'Archivio, Massimo; Scazzocchio, Beatrice; Filesi, Carmela; Varì, Rosaria; Maggiorella, Maria Teresa; Sernicola, Leonardo; Santangelo, Carmela; Giovannini, Claudio; Masella, Roberta

    2008-06-25

    The effect of oxLDL on CD36 expression has been assessed in preadipocytes induced to differentiate. Novel evidence is provided that oxLDL induce a peroxisome proliferator-activated receptor gamma-independent CD36 overexpression, by up-regulating nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2). The nuclear translocation of Nrf2 appeared to depend on PKC pathway activation. In adipocytes, the CD36 up-regulation may indicate a compensation mechanism to meet the demand of excess oxLDL and oxidised lipids in blood, reducing the risk of atherogenesis. Besides strengthening the hypothesis that oxLDL can contribute to the onset of insulin-resistance, data herein presented highlight the significance of oxLDL-induced CD36 overexpression within the cellular defence response. PMID:18514070

  11. Purple perilla extracts with α-asarone enhance cholesterol efflux from oxidized LDL-exposed macrophages.

    PubMed

    Park, Sin-Hye; Paek, Ji Hun; Shin, Daekeun; Lee, Jae-Yong; Lim, Soon Sung; Kang, Young-Hee

    2015-04-01

    The cellular accumulation of cholesterol is critical in the development and progression of atherosclerosis. ATP-binding cassette (ABC) transporters play an essential role in mediating the efflux of excess cholesterol. In the current study, we investigated whether purple Perilla frutescens extracts (PPE) at a non-toxic concentration of 1-10 µg/ml stimulate the induction of the ABC transporters, ABCA1 and ABCG1, and cholesterol efflux from lipid-laden J774A.1 murine macrophages exposed to 50 ng/ml oxidized low-density lipoprotein (LDL). Purple perilla, an annual herb in the mint family and its constituents, have been reported to exhibit antioxidant and cytostatic activity, as well as to exert anti-allergic effects. Our results revealed that treatment with oxidized LDL for 24 h led to the accumulation of lipid droplets in the macrophages. PPE suppressed the oxidized LDL-induced foam cell formation by blocking the induction of scavenger receptor B1. However, PPE promoted the induction of the ABC transporters, ABCA1 and ABCG1, and subsequently accelerated cholesterol efflux from the lipid-loaded macrophages. The liver X receptor (LXR) agonist, TO-091317, and the peroxisome proliferator-activated receptor (PPAR) agonist, pioglitazone, increased ABCA1 expression and treatment with 10 µg/ml PPE further enhanced this effect. PPE did not induce LXRα and PPARγ expression per se, but enhanced their expression in the macrophages exposed to oxidized LDL. α-asarone was isolated from PPE and characterized as a major component enhancing the induction of ABCA1 and ABCG1 in macrophages exposed to oxidized LDL. α-asarone, but not β-asarone was effective in attenuating foam cell formation and enhancing cholesterol efflux, revealing an isomeric difference in their activity. The results from the present study demonstrate that PPE promotes cholesterol efflux from macrophages by activating the interaction of PPARγ-LXRα-ABC transporters. PMID:25673178

  12. Studies of LDL oxidation following alpha-, gamma-, or delta-tocotrienyl acetate supplementation of hypercholesterolemic humans.

    PubMed

    O'Byrne, D; Grundy, S; Packer, L; Devaraj, S; Baldenius, K; Hoppe, P P; Kraemer, K; Jialal, I; Traber, M G

    2000-11-01

    In vitro tocotrienols (T3s) have potent vitamin E antioxidant activity, but unlike tocopherols can inhibit cholesterol synthesis by suppressing 3-hydroxy-3-methyl-glutarylCoA (HMG-CoA) reductase. Because hypercholesterolemia is a major risk factor for coronary artery disease and oxidative modification of low-density lipoprotein (LDL) may be involved in atherogenesis, we investigated whether daily supplements of placebo, or alpha-, gamma-, or delta- (alpha-, gamma-, or delta-) tocotrienyl acetates would alter serum cholesterol or LDL oxidative resistance in hypercholesterolemics in a double-blind placebo controlled study. Subjects were randomly assigned to receive placebo (n = 13), alpha- (n = 13), gamma- (n = 12), or delta- (n = 13) tocotrienyl acetate supplements (250 mg/d). All subjects followed a low-fat diet for 4 weeks, then took supplements with dinner for the following 8 weeks while still continuing diet restrictions. Plasma alpha- and gamma-tocopherols were unchanged by supplementation. Plasma T3s were undetectable initially and always in the placebo group. Following supplementation in the respective groups plasma concentrations were: alpha-T3 0.98 +/- 0.80 micromol/l, gamma-T3 0.54 +/- 0.45 micromol/l, and delta-T3 0.09 +/- 0.07 micromol/l. Alpha-T3 increased in vitro LDL oxidative resistance (+22%, p <.001) and decreased its rate of oxidation (p <. 01). Neither serum or LDL cholesterol nor apolipoprotein B were significantly decreased by tocotrienyl acetate supplements. This study demonstrates that: (i) tocotrienyl acetate supplements are hydrolyzed, absorbed, and detectable in human plasma; (ii) tocotrienyl acetate supplements do not lower cholesterol in hypercholesterolemic subjects on low-fat diets; and (iii) alpha-T3 may be potent in decreasing LDL oxidizability. PMID:11063909

  13. Native LDL-induced oxidative stress in human proximal tubular cells: multiple players involved

    PubMed Central

    Piccoli, Claudia; Quarato, Giovanni; D’Aprile, Annamaria; Montemurno, Eustacchio; Scrima, Rosella; Ripoli, Maria; Gomaraschi, Monica; Cirillo, Pietro; Boffoli, Domenico; Calabresi, Laura; Gesualdo, Loreto; Capitanio, Nazzareno

    2011-01-01

    Abstract Dyslipidemia is a well-established condition proved to accelerate the progression of chronic kidney disease leading to tubulo-interstitial injury. However, the molecular aspects of the dyslipidemia-induced renal damage have not been fully clarified and in particular the role played by low-density lipoproteins (LDLs). This study aimed to examine the effects of native non-oxidized LDL on cellular oxidative metabolism in cultured human proximal tubular cells. By means of confocal microscopy imaging combined to respirometric and enzymatic assays it is shown that purified native LDL caused a marked increase of cellular reactive oxygen species (ROS) production, which was mediated by activation of NADPH oxidase(s) and by mitochondrial dysfunction by means of a ROS-induced ROS release mechanism. The LDL-dependent mitochondrial alterations comprised inhibition of the respiratory chain activity, enhanced ROS production, uncoupling of the oxidative phosphorylation efficiency, collapse of the mtΔΨ, increased Ca2+ uptake and loss of cytochrome c. All the above LDL-induced effects were completely abrogated by chelating extracellular Ca2+ as well as by inhibition of the Ca2+-activated cytoplas-mic phospholipase A2, NADPH oxidase and mitochondrial permeability transition. We propose a mechanicistic model whereby the LDL-induced intracellular redox unbalance is triggered by a Ca2+ inward flux-dependent commencement of cPLA2 followed by activation of a lipid- and ROS-based cross-talking signalling pathway. This involves first oxidants production via the plasmamembrane NADPH oxidase and then propagates downstream to mitochondria eliciting redox- and Ca2+-dependent dysfunctions leading to cell-harming conditions. These findings may help to clarify the mechanism of dyslipidemia-induced renal damage and suggest new potential targets for specific therapeutic strategies to prevent oxidative stress implicated in kidney diseases. PMID:19863698

  14. Iron in human atheroma and LDL oxidation by macrophages following erythrophagocytosis.

    PubMed

    Yuan, X M; Anders, W L; Olsson, A G; Brunk, U T

    1996-07-01

    The oxidative modification of low density lipoprotein (LDL) has been implicated as an early step in the formation of atheromatous lesions. In vitro studies suggest it to be accelerated, or even initiated, by transition metals such as iron or copper in combination with a reducing agent. Even if such metals have been demonstrated in atheroma gruels, their origin and precise localisation within human atheroma are presently unknown. In the initial part of this study we applied Pearl's method, energy dispersive X-ray microanalysis, and a modified Timm sulphide silver method (SSM) to demonstrate the occurrence of iron in early atherosclerotic lesions from a number of consecutive autopsy cases with evident, general atheromatosis. With the very sensitive SSM, but not with the other techniques, we found foam cells to contain heavy metals with a mainly lysosomal localization. On the basis of the hypothesis that such a lysosomal accumulation of iron might be due to erythrophagocytosis by migrating tissue-bound macrophages that later develop into foam cells, we designed an in vitro model system where human monocyte-derived macrophages were exposed to artificially aged, UV-exposed erythrocytes. The macrophages were then exposed to LDL in serum-and iron-free RPMI medium, occasionally in the presence of the potent iron-chelator desferrioxamine. The capacity of macrophages to oxidise LDL was much enhanced following erythrophagocytosis, and the process was shown to involve secretion of iron. Consequently, LDL oxidation was greatly inhibited by desferrioxamine. We conclude that iron may be exocytosed by macrophages that previously had their lysosomal apparatus enriched with iron, e.g. due to erythrophagocytosis. Oxidation of LDL may result in ensuing foam cell-formation secondary to scavenger-receptor mediated endocytosis by macrophages. PMID:8800494

  15. Inhibition of Macrophage CD36 Expression and Cellular Oxidized Low Density Lipoprotein (oxLDL) Accumulation by Tamoxifen: A PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR (PPAR)γ-DEPENDENT MECHANISM.

    PubMed

    Yu, Miao; Jiang, Meixiu; Chen, Yuanli; Zhang, Shuang; Zhang, Wenwen; Yang, Xiaoxiao; Li, Xiaoju; Li, Yan; Duan, Shengzhong; Han, Jihong; Duan, Yajun

    2016-08-12

    Macrophage CD36 binds and internalizes oxidized low density lipoprotein (oxLDL) to facilitate foam cell formation. CD36 expression is activated by peroxisome proliferator-activated receptor γ (PPARγ). Tamoxifen, an anti-breast cancer medicine, has demonstrated pleiotropic functions including cardioprotection with unfully elucidated mechanisms. In this study, we determined that treatment of ApoE-deficient mice with tamoxifen reduced atherosclerosis, which was associated with decreased CD36 and PPARγ expression in lesion areas. At the cellular level, we observed that tamoxifen inhibited CD36 protein expression in human THP-1 monocytes, THP-1/PMA macrophages, and human blood monocyte-derived macrophages. Associated with decreased CD36 protein expression, tamoxifen reduced cellular oxLDL accumulation in a CD36-dependent manner. At the transcriptional level, tamoxifen decreased CD36 mRNA expression, promoter activity, and the binding of the PPARγ response element in CD36 promoter to PPARγ protein. Tamoxifen blocked ligand-induced PPARγ nuclear translocation and CD36 expression, but it increased PPARγ phosphorylation, which was due to that tamoxifen-activated ERK1/2. Furthermore, deficiency of PPARγ expression in macrophages abolished the inhibitory effect of tamoxifen on CD36 expression or cellular oxLDL accumulation both in vitro and in vivo Taken together, our study demonstrates that tamoxifen inhibits CD36 expression and cellular oxLDL accumulation by inactivating the PPARγ signaling pathway, and the inhibition of macrophage CD36 expression can be attributed to the anti-atherogenic properties of tamoxifen. PMID:27358406

  16. Relationship between the G75A polymorphism in the apolipoprotein A1 (ApoA1) gene and the lipid regulatory effects of pravastatin in patients with hyperlipidemia.

    PubMed

    Liu, T N; Wu, C T; He, F; Yuan, W; Li, S X; Li, H W; Yu, H Y; Wu, M

    2016-01-01

    In this study, we investigated the relationship between the G75A polymorphism in the apolipoprotein A1 (ApoA1) gene and the lipid regulatory effect of pravastatin in patients with hyperlipidemia. A total of 179 patients were divided into two groups: the pravastatin (N = 97) and policosanol (N = 82) treatment groups. The total cholesterol (TC), triglyceride, low-density lipoprotein (LDL-c), high-density lipoprotein, ApoA, and ApoB concentrations in the serum were measured using an automatic biochemical analyzer before and after treatment for 12 weeks. The genotypes of the ApoA1 G75A SNP were detected by polymerase chain reaction-restriction fragment length polymorphism, and were subsequently statistically analyzed. Pravastatin treatment induced a significant decrease in the TC, LDL-c, and ApoB levels in patients expressing the ApoA1 AA+GA genotype (P < 0.05), and not in those expressing the GG genotype (P > 0.05). However, policosanol treatment induced a non-significant decrease in the serum TC levels (P > 0.05) and a significant decrease in the ApoB levels (P < 0.05), and did not induce a decrease in the LDL-c (P > 0.05) levels in patients with the AA+GA genotype. Policosanol also induced a significant decrease in the TC and LDL-c levels in patients with the GG genotype (P < 0.05). The various genotypes of the ApoA1 G75A SNP influence the efficacy of lipid regulation by pravastatin and policosanol in patients with hyperlipidemia. PMID:27323196

  17. Resveratrol Enhances Autophagic Flux and Promotes Ox-LDL Degradation in HUVECs via Upregulation of SIRT1

    PubMed Central

    Zhang, Yanlin; Cao, Xueqin; Zhu, Wawa; Liu, Zhihua; Liu, Huihui; Zhou, Yande; Cao, Yongjun; Liu, Chunfeng; Xie, Ying

    2016-01-01

    Oxidized low-density lipoprotein- (Ox-LDL-) induced autophagy dysfunction in human vascular endothelial cells contributes to the development of atherosclerosis (AS). Resveratrol (RSV) protects against Ox-LDL-induced endothelium injury. The objective of this study was to determine the mechanisms underlying Ox-LDL-induced autophagy dysfunction and RSV-mediated protection in human umbilical vein endothelial cells (HUVECs). The results showed that Ox-LDL suppressed the expression of sirtuin 1 (SIRT1) and increased LC3-II and sequestosome 1 (p62) protein levels without altering p62 mRNA levels in HUVECs. Pretreatment with bafilomycin A1 (BafA1) to inhibit lysosomal degradation abrogated the Ox-LDL-induced increase in LC3-II protein level. Ox-LDL increased colocalization of GFP and RFP puncta in mRFP-GFP-tandem fluorescent LC3- (tf-LC3-) transfected cells. Moreover, Ox-LDL decreased the expression of mature cathepsin D and attenuated cathepsin D activity. Pretreatment with RSV increased the expression of SIRT1 and LC3-II and increased p62 protein degradation. RSV induced RFP-LC3 aggregation more than GFP-LC3 aggregation. RSV restored lysosomal function and promoted Ox-LDL degradation in HUVECs. All the protective effects of RSV were blocked after SIRT1 was knocked down. These findings demonstrated that RSV upregulated the expression of SIRT1, restored lysosomal function, enhanced Ox-LDL-induced impaired autophagic flux, and promoted Ox-LDL degradation through the autophagy-lysosome degradation pathway in HUVECs. PMID:27069532

  18. Oxidized LDL induced extracellular trap formation in human neutrophils via TLR-PKC-IRAK-MAPK and NADPH-oxidase activation.

    PubMed

    Awasthi, Deepika; Nagarkoti, Sheela; Kumar, Amit; Dubey, Megha; Singh, Abhishek Kumar; Pathak, Priya; Chandra, Tulika; Barthwal, Manoj Kumar; Dikshit, Madhu

    2016-04-01

    Neutrophil extracellular traps (NETs) formation was initially linked with host defence and extracellular killing of pathogens. However, recent studies have highlighted their inflammatory potential. Oxidized low density lipoprotein (oxLDL) has been implicated as an independent risk factor in various acute or chronic inflammatory diseases including systemic inflammatory response syndrome (SIRS). In the present study we investigated effect of oxLDL on NETs formation and elucidated the underlying signalling mechanism. Treatment of oxLDL to adhered PMNs led to a time and concentration dependent ROS generation and NETs formation. OxLDL induced free radical formation and NETs release were significantly prevented in presence of NADPH oxidase (NOX) inhibitors suggesting role of NOX activation in oxLDL induced NETs release. Blocking of both toll like receptor (TLR)-2 and 6 significantly reduced oxLDL induced NETs formation indicating requirement of both the receptors. We further identified Protein kinase C (PKC), Interleukin-1 receptor associated kinase (IRAKs), mitogen-activated protein kinase (MAPK) pathway as downstream intracellular signalling mediators involved in oxLDL induced NETs formation. OxLDL components such as oxidized phospholipids (lysophosphatidylcholine (LPC) and oxidized 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphorylcholine (oxPAPC)) were most potent NETs inducers and might be crucial for oxLDL mediating NETs release. Other components like, oxysterols, malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) were however less potent as compared to oxidized phospholipids. This study thus demonstrates for the first time that treatment of human PMNs with oxLDL or its various oxidized phopholipid component mediated NETs release, implying their role in the pathogenesis of inflammatory diseases such as SIRS. PMID:26774674

  19. Cloning and expression of an anti-LDL(-) single-chain variable fragment, and its inhibitory effect on experimental atherosclerosis

    PubMed Central

    Kazuma, Soraya M; Cavalcante, Marcela F; Telles, Andréia ER; Maranhão, Andrea Queiroz; Abdalla, Dulcineia SP

    2013-01-01

    The in vivo modified forms of low-density lipoprotein (LDL) are important for the formation of foam cells and as mediators of the immuno-inflammatory process involved in the progression of atherosclerosis. Electronegative LDL, LDL(-), is a LDL subfraction with pro-inflammatory properties that is present in human blood. To investigate possible atheroprotective effects, an anti-LDL(-) single-chain variable fragment (scFv) was expressed in the methylotrophic yeast Pichia pastoris and its activity was evaluated in vitro against macrophages and in experimental atherosclerosis in Ldlr-/-mice. The recombinant 2C7 scFv was produced in a yield of 9.5 mg of protein/L. The specificity and affinity of purified 2C7 scFv against LDL(-) was confirmed by ELISA. To assess the activity of 2C7 scFv on foam cell formation, RAW 264.7 macrophages were exposed to LDL(-) in the presence or absence of 2C7 scFv. The 2C7 scFv inhibited the uptake of LDL(-) by macrophages in a dose-dependent manner, and internalization of LDL(-) by these cells was found to be mediated by the CD36 and CD14 receptor. In addition, compared with untreated cells, lipid accumulation in macrophages was decreased, and the expression of Cd36, Tlr-4 and Cox-2 was downregulated in macrophages treated with 2C7 scFv. Importantly, compared with untreated mice, the treatment of Ldlr-/- mice with 2C7 scFv decreased the atherosclerotic lesion area at the aortic sinus. In conclusion, our data show that 2C7 scFv inhibits foam cell formation and atherosclerotic plaque development by modulating the expression of genes relevant to atherogenesis. These results encourage further use of this antibody fragment in the development of new therapeutic strategies that neutralize the pro-atherogenic effects of LDL(-). PMID:23924793

  20. Associations of Circulating Oxidized LDL and Conventional Biomarkers of Cardiovascular Disease in a Cross-Sectional Study of the Navajo Population

    PubMed Central

    Harmon, Molly E.; Campen, Matthew J.; Miller, Curtis; Shuey, Chris; Cajero, Miranda; Lucas, Selita; Pacheco, Bernadette; Erdei, Esther; Ramone, Sandy; Nez, Teddy; Lewis, Johnnye

    2016-01-01

    The prevalences of cardiovascular disease (CVD) and type 2 diabetes (T2D) have increased among the Navajo Native American community in recent decades. Oxidized low-density lipoprotein (oxLDL) is a novel CVD biomarker that has never been assessed in the Navajo population. We examined the relationship of oxLDL to conventional CVD and T2D risk factors and biomarkers in a cross-sectional population of Navajo participants. This cross-sectional study included 252 participants from 20 Navajo communities from the Diné Network for Environmental Health Project. Plasma samples were tested for oxLDL levels by a sandwich enzyme-linked immunosorbent assay. Univariate and multivariate analyses were used to determine the relationship of oxLDL and oxidized- to non-oxidized lipoprotein ratios to glycated hemoglobin (HbA1c), C-reactive protein (CRP), interleukin 6 (IL6) and demographic and health variables. Type 2 diabetes, hypertension and obesity are very prevalent in this Navajo population. HbA1c, CRP, body mass index (BMI), high-density lipoprotein, and triglycerides were at levels that may increase risk for CVD and T2D. Median oxLDL level was 47 (36.8–57) U/L. Correlational analysis showed that although oxLDL alone was not associated with HbA1c, oxLDL/HDL, oxLDL/LDL and CRP were significantly associated with HbA1c and glucose. OxLDL, oxLDL/HDL and oxLDL/LDL were significantly associated with CRP. Multivariate analysis showed that triglycerides were a common and strong predictor of oxLDL, oxLDL/HDL and oxLDL/LDL. OxLDL was trended with HbA1c and glucose but did not reach significance, however, HbA1c was an independent predictor of OxLDL/HDL. CRP trended with oxLDL/HDL and was a weak predictor of oxLDL/LDL. This Navajo subset appears to have oxLDL levels comparable to subjects without evidence of CVD reported in other studies. The high prevalence of T2D, hypertension and obesity along with abnormal levels of other biomarkers including HbA1c indicate that the Navajo population

  1. Associations of Circulating Oxidized LDL and Conventional Biomarkers of Cardiovascular Disease in a Cross-Sectional Study of the Navajo Population.

    PubMed

    Harmon, Molly E; Campen, Matthew J; Miller, Curtis; Shuey, Chris; Cajero, Miranda; Lucas, Selita; Pacheco, Bernadette; Erdei, Esther; Ramone, Sandy; Nez, Teddy; Lewis, Johnnye

    2016-01-01

    The prevalences of cardiovascular disease (CVD) and type 2 diabetes (T2D) have increased among the Navajo Native American community in recent decades. Oxidized low-density lipoprotein (oxLDL) is a novel CVD biomarker that has never been assessed in the Navajo population. We examined the relationship of oxLDL to conventional CVD and T2D risk factors and biomarkers in a cross-sectional population of Navajo participants. This cross-sectional study included 252 participants from 20 Navajo communities from the Diné Network for Environmental Health Project. Plasma samples were tested for oxLDL levels by a sandwich enzyme-linked immunosorbent assay. Univariate and multivariate analyses were used to determine the relationship of oxLDL and oxidized- to non-oxidized lipoprotein ratios to glycated hemoglobin (HbA1c), C-reactive protein (CRP), interleukin 6 (IL6) and demographic and health variables. Type 2 diabetes, hypertension and obesity are very prevalent in this Navajo population. HbA1c, CRP, body mass index (BMI), high-density lipoprotein, and triglycerides were at levels that may increase risk for CVD and T2D. Median oxLDL level was 47 (36.8-57) U/L. Correlational analysis showed that although oxLDL alone was not associated with HbA1c, oxLDL/HDL, oxLDL/LDL and CRP were significantly associated with HbA1c and glucose. OxLDL, oxLDL/HDL and oxLDL/LDL were significantly associated with CRP. Multivariate analysis showed that triglycerides were a common and strong predictor of oxLDL, oxLDL/HDL and oxLDL/LDL. OxLDL was trended with HbA1c and glucose but did not reach significance, however, HbA1c was an independent predictor of OxLDL/HDL. CRP trended with oxLDL/HDL and was a weak predictor of oxLDL/LDL. This Navajo subset appears to have oxLDL levels comparable to subjects without evidence of CVD reported in other studies. The high prevalence of T2D, hypertension and obesity along with abnormal levels of other biomarkers including HbA1c indicate that the Navajo population has

  2. ApoE Receptor 2 mediates trophoblast dysfunction and pregnancy complications induced by antiphospholipid antibodies in mice

    PubMed Central

    Ulrich, Victoria; Gelber, Shari E.; Vukelic, Milena; Sacharidou, Anastasia; Herz, Joachim; Urbanus, Rolf T.; de Groot, Philip G.; Natale, David R.; Harihara, Anirudha; Redecha, Patricia; Abrahams, Vikki M.; Shaul, Philip W.

    2015-01-01

    Objective Pregnancies in women with the antiphospholipid syndrome (APS) are frequently complicated by fetal loss and intrauterine growth restriction (IUGR). How circulating antiphospholipid antibodies (aPL) cause pregnancy complications in APS is poorly understood. We sought to determine if the LDL receptor family member apoE receptor 2 (apoER2) mediates trophoblast dysfunction and pregnancy complications induced by aPL. Methods Placental and trophoblast apoER2 expression was evaluated by immunohistochemistry and immunoblotting. Normal human IgG (NHIgG) and aPL were purified from healthy individuals and APS patients, respectively. The role of apoER2 in aPL-induced changes in trophoblast proliferation, migration and kinase activation was assessed using RNA interference in HTR-8/SVneo cells. The participation of apoER2 in aPL-induced pregnancy loss and IUGR was evaluated in pregnant apoER2+/+ and apoER2−/− mice injected with aPL or NHIgG. Results We found that apoER2 is abundant in human and mouse placental trophoblasts, and in multiple trophoblast-derived cell lines including HTR-8/SVneo cells. ApoER2 and its interaction with the cell surface protein β2-glycoprotein I were required for aPL-induced inhibition of cultured trophoblast proliferation and migration. In parallel, aPL antagonism of Akt kinase activation by EGF in trophoblasts was mediated by apoER2. Furthermore, in a murine passive transfer model of pregnancy complications of APS, apoER2−/− mice were protected from both aPL-induced fetal loss and aPL-induced IUGR. Conclusion ApoER2 plays a major role in the attenuation of trophoblast function by aPL, and the receptor mediates aPL-induced pregnancy complications in vivo in mice. ApoER2-directed interventions can now potentially be developed to combat the pregnancy complications associated with APS. PMID:26474194

  3. Difference in LDL receptor feedback regulation in macrophages and vascular smooth muscle cells: foam cell transformation under inflammatory stress.

    PubMed

    Ye, Qiang; Lei, Han; Fan, Zhongcai; Zheng, Wenwu; Zheng, Shuzhan

    2014-04-01

    Macrophages and vascular smooth muscle cells (VSMCs) are the major cell types involved in foam cell formation associated with atherosclerosis. The aim of this experiment was to clarify cell-specific regulation of LDL receptor in THP-1 macrophages and human VSMCs under physiological and inflammatory conditions and its potential mechanisms. Inflammatory stress was induced by adding lipopolysaccharide (LPS) to human THP-1 macrophages and human VSMCs. Intracellular total cholesterol, free cholesterol, and cholesterol ester were measured by an enzymic assay. Oil Red O staining was used to visualize lipid droplet accumulation in cells. Total cellular RNA was isolated from cells for detecting LDL receptor, sterol regulatory element binding protein (SREBP)-2 and SREBP cleavage-activating protein (SCAP) mRNA levels using real-time quantitative polymerase chain reaction. LDL receptor, SREBP-2 and SCAP protein expression were examined by Western blotting. The translocation of SCAP from ER to Golgi was detected by confocal microscopy. LDL loading increased intracellular cholesterol level, reducing LDL receptor mRNA level in both THP-1 macrophages and VSMCs under physiological conditions. The IC50 in VSMCs was 11.25 μg/ml, which is much lower than 18.125 μg/ml in THP-1 macrophages. With the increase in concentration of LPS (0-400 ng/ml), the LDL receptor mRNA levels were upregulated in both cells, but the curve of LDL receptor mRNA in VSMCs exhibited a flatter profile than that of THP-1 macrophages. Under the treatment of 200 ng/ml of LPS, the upregulation fold of the LDL receptor mRNA in THP-1 macrophages was much higher than that of VSMCs (0.33 vs 0.04). LDL receptor blocking agent heparin decreased lipid droplets induced by LPS significantly in THP-1 macrophages and VSMCs. LDL loading reduced the SREBP2 and SCAP protein expression under physiological conditions. Exposure to LPS caused overexpression of SREBP2 and SCAP despite a high concentration of LDL in the culture

  4. ApoC-III: a potent modulator of hypertriglyceridemia and cardiovascular disease

    PubMed Central

    Kohan, Alison B.

    2015-01-01

    Purpose of review To summarize the recent epidemiological, basic science, and pharmaceutical research linking apoC-III with the development and treatment of cardiovascular disease. Recent findings ApoC-III is an important emerging target linking hypertriglyceridemia with cardiovascular disease (CVD). ApoC-III is a potent modulator of many established CVD risk factors, and is found on chylomicrons, VLDL, LDL, and HDL particles. Recent studies show that in humans, apoC-III levels are an independent risk factor for CVD, and its presence on lipoproteins may promote their atherogenicity. This year, two large-scale epidemiological studies have linked mutations in apoC-III with increased incidence of cardiovascular disease and hypertriglyceridemia. ApoC-III raises plasma triglycerides through inhibition of LPL, stimulation of VLDL secretion, and is a novel factor in modulating intestinal triglyceride trafficking. ApoC-III also stimulates inflammatory processes in the vasculature and in the pancreas. The combination of raising plasma triglycerides and independently stimulating inflammatory processes makes apoC-III a valuable target for reducing the residual CVD risk in patients already on statin therapy, or for whom triglycerides are poorly controlled. Clinical trials on apoC-III antisense oligonucleotides are in progress. Summary ApoC-III is a potent direct modulator of established cardiovascular disease risk factors: plasma triglycerides and inflammation. Recent findings show that changes in apoC-III levels are directly associated with changes in cardiovascular risk, and with the atherogenicity of the lipoproteins on which apoC-III resides. Emerging roles of apoC-III include a role in directing the atherogenicity of HDL, intestinal dietary triglyceride trafficking, and modulating pancreatic β-cell survival. The combination of these roles makes apoC-III an important therapeutic target for the management and prevention of cardiovascular disease. PMID:25692924

  5. Mipu1 overexpression protects macrophages from oxLDL-induced foam cell formation and cell apoptosis.

    PubMed

    Qu, Shun-Lin; Fan, Wen-Jing; Zhang, Chi; Guo, Fang; Han, Dan; Pan, Wen-Jun; Li, Wei; Feng, Da-Ming; Jiang, Zhi-Sheng

    2014-12-01

    Mipu1 (myocardial ischemic preconditioning upregulated protein 1) is a novel N-terminal Kruppel-associated box (KRAB)/C2H2 zinc finger superfamily protein, that displays a powerful effect in protecting H9c2 cells from oxidative stress-induced cell apoptosis. The present study aims to investigate the effect of Mipu1 overexpression on oxidized low-density lipoprotein (oxLDL)-induced foam cell formation, cell apoptosis, and its possible mechanisms. New Zealand healthy rabbits were used to establish atherosclerosis model, and serum levels of triglycerides, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol were detected by an automatic biochemical analyzer. Sudan IV staining was used to detect atherosclerotic lesions. The RAW264.7 macrophage cell line was selected as the experimental material. Oil red O staining, high-performance liquid chromatography, and Dil-labeled lipoprotein were used to detect cholesterol accumulation qualitatively and quantitatively, respectively. Flow cytometry was used to determine cell apoptosis. Real-time quantitative polymerase chain reaction (PCR) was used to detect the mRNA expression of the main proteins that are associated with the transport of cholesterol, such as ABCA1, ABCG1, SR-BI, and CD36. Western blot analysis was used to detect the protein expression of Mipu1. There were atherosclerotic lesions in the high-fat diet group with Sudan IV staining. High-fat diet decreased Mipu1 expression and increased CD36 expression significantly at the 10th week compared with standard-diet rabbits. Mipu1 overexpression decreased oxLDL-induced cholesterol accumulation, oxLDL uptake, cell apoptosis, and cleaved caspase-3. Mipu1 overexpression inhibited the oxLDL-induced CD36 mRNA and protein expression, but it did not significantly inhibit the mRNA expression of ABCA1, ABCG1, and SR-BI. Mipu1 overexpression inhibits oxLDL-induced foam cell formation and cell apoptosis. Mipu1 overexpression reduces the

  6. K Domain CR9 of Low Density Lipoprotein (LDL) Receptor-related Protein 1 (LRP1) Is Critical for Aggregated LDL-induced Foam Cell Formation from Human Vascular Smooth Muscle Cells*

    PubMed Central

    Costales, Paula; Fuentes-Prior, Pablo; Castellano, Jose; Revuelta-Lopez, Elena; Corral-Rodríguez, Maria Ángeles; Nasarre, Laura; Badimon, Lina; Llorente-Cortes, Vicenta

    2015-01-01

    Low density lipoprotein receptor-related protein (LRP1) mediates the internalization of aggregated LDL (AgLDL), which in turn increases the expression of LRP1 in human vascular smooth muscle cells (hVSMCs). This positive feedback mechanism is thus highly efficient to promote the formation of hVSMC foam cells, a crucial vascular component determining the susceptibility of atherosclerotic plaque to rupture. Here we have determined the LRP1 domains involved in AgLDL recognition with the aim of specifically blocking AgLDL internalization in hVSMCs. The capacity of fluorescently labeled AgLDL to bind to functional LRP1 clusters was tested in a receptor-ligand fluorometric assay made by immobilizing soluble LRP1 “minireceptors” (sLRP1-II, sLRP1-III, and sLRP1-IV) recombinantly expressed in CHO cells. This assay showed that AgLDL binds to cluster II. We predicted three well exposed and potentially immunogenic peptides in the CR7–CR9 domains of this cluster (termed P1 (Cys1051–Glu1066), P2 (Asp1090–Cys1104), and P3 (Gly1127–Cys1140)). AgLDL, but not native LDL, bound specifically and tightly to P3-coated wells. Rabbit polyclonal antibodies raised against P3 prevented AgLDL uptake by hVSMCs and were almost twice as effective as anti-P1 and anti-P2 Abs in reducing intracellular cholesteryl ester accumulation. Moreover, anti-P3 Abs efficiently prevented AgLDL-induced LRP1 up-regulation and counteracted the down-regulatory effect of AgLDL on hVSMC migration. In conclusion, domain CR9 appears to be critical for LRP1-mediated AgLDL binding and internalization in hVSMCs. Our results open new avenues for an innovative anti-VSMC foam cell-based strategy for the treatment of vascular lipid deposition in atherosclerosis. PMID:25918169

  7. Molecular Etiology of Atherogenesis – In Vitro Induction of Lipidosis in Macrophages with a New LDL Model

    PubMed Central

    Estronca, Luis M. B. B.; Silva, Joao C. P.; Sampaio, Julio L.; Shevchenko, Andrej; Verkade, Paul; Vaz, Alfin D. N.; Vaz, Winchil L. C.; Vieira, Otilia V.

    2012-01-01

    Background Atherosclerosis starts by lipid accumulation in the arterial intima and progresses into a chronic vascular inflammatory disease. A major atherogenic process is the formation of lipid-loaded macrophages in which a breakdown of the endolysomal pathway results in irreversible accumulation of cargo in the late endocytic compartments with a phenotype similar to several forms of lipidosis. Macrophages exposed to oxidized LDL exihibit this phenomenon in vitro and manifest an impaired degradation of internalized lipids and enhanced inflammatory stimulation. Identification of the specific chemical component(s) causing this phenotype has been elusive because of the chemical complexity of oxidized LDL. Methodology/Principal Findings Lipid “core aldehydes" are formed in oxidized LDL and exist in atherosclerotic plaques. These aldehydes are slowly oxidized in situ and (much faster) by intracellular aldehyde oxidizing systems to cholesteryl hemiesters. We show that a single cholesteryl hemiester incorporated into native, non-oxidized LDL induces a lipidosis phenotype with subsequent cell death in macrophages. Internalization of the cholesteryl hemiester via the native LDL vehicle induced lipid accumulation in a time- and concentration-dependent manner in “frozen" endolysosomes. Quantitative shotgun lipidomics analysis showed that internalized lipid in cholesteryl hemiester-intoxicated cells remained largely unprocessed in those lipid-rich organelles. Conclusions/Significance The principle elucidated with the present cholesteryl hemiester-containing native-LDL model, extended to other molecular components of oxidized LDL, will help in defining the molecular etiology and etiological hierarchy of atherogenic agents. PMID:22514671

  8. Oxidized LDL binding to LOX-1 upregulates VEGF expression in cultured bovine chondrocytes through activation of PPAR-{gamma}

    SciTech Connect

    Kanata, Sohya; Akagi, Masao . E-mail: makagi@med.kindai.ac.jp; Nishimura, Shunji; Hayakawa, Sumio; Yoshida, Kohji; Sawamura, Tatsuya; Munakata, Hiroshi; Hamanishi, Chiaki

    2006-09-29

    It has been reported that vascular endothelial growth factor (VEGF) and its receptors play an important role in the destruction of articular cartilage in osteoarthritis through increased production of matrix metalloproteinases. We investigated whether the oxidized low-density lipoprotein (ox-LDL) binding to lectin-like ox-LDL receptor-1 (LOX-1) upregulates VEGF expression in cultured bovine articular chondrocytes (BACs). Ox-LDL markedly increased VEGF mRNA expression and protein release in time- and dose-dependent manners, which was significantly suppressed by anti-LOX-1 antibody pretreatment. Activation of peroxisome proliferator-activated receptor (PPAR)-{gamma} was evident in BACs with ox-LDL addition and was attenuated by anti-LOX-1 antibody. The specific PPAR-{gamma} inhibitor GW9662 suppressed ox-LDL-induced VEGF expression. These results suggest that the ox-LDL/LOX-1 system upregulates VEGF expression in articular cartilage, at least in part, through activation of PPAR-{gamma} and supports the hypothesis that ox-LDL is involved in cartilage degradation via LOX-1.

  9. [Ox-LDL down-regulates expression of pigment epithelium-derived factor in human umbilical vein endothelial cells].

    PubMed

    Liu, Jie; Yao, Shu-Tong; Zhai, Lei; Feng, Yue-Long; Song, Guo-Hua; Yu, Yang; Zhu, Ping; Qin, Shu-Cun

    2014-08-25

    Pigment epithelium-derived factor (PEDF) is a multifunctional protein with anti-inflammatory, antioxidant and antithrombotic properties and plays a protective role against atherosclerosis (AS). The purpose of the present study is to explore the effects of oxidized low density lipoprotein (ox-LDL) on the expression of PEDF in cultured human umbilical vein endothelial cells (HUVECs). HUVECs were cultured and incubated with ox-LDL at different concentrations (6.25, 12.5, 25, 50, 100 and 150 mg/L) for 24 h. Apoptosis of endothelial cells were assayed by morphological staining and flow cytometry. The intracellular reactive oxygen species (ROS) levels were measured by flow cytometry. Cell viability was assayed by MTT assay. PEDF protein and mRNA expressions in HUVECs were analyzed by Western blot and quantitative real-time PCR, respectively. The results showed that ox-LDL significantly induced apoptosis, reduced cell viability, increased intracellular ROS levels and decreased the PEDF expression in HUVECs in a concentration-dependent manner. Ox-LDL at 50 mg/L obviously decreased the PEDF protein expression compared with control group (P < 0.05), whereas 25 mg/L ox-LDL already markedly reduced the PEDF mRNA expression (P < 0.05). In conclusion, the results suggest that ox-LDL down-regulates the PEDF expression through an increased ox-LDL-induced intracellular production of ROS. PMID:25131792

  10. Effects of liposome-encapsulated bisphosphonates on acetylated LDL metabolism, lipid accumulation and viability of phagocyting cells.

    PubMed

    Ylitalo, R; Mönkkönen, J; Ylä-Herttuala, S

    1998-01-01

    Bisphosphonates, the drugs used for the treatment of e.g. osteoporosis, inhibit the development of experimental atherosclerosis. When encapsulated in liposomes, they also inactivate macrophages, which have a key role in atherogenesis. We studied the effects of three clinically used bisphosphonates, i.e. clodronate, etidronate and pamidronate, on 1) the viability of mouse peritoneal macrophages and macrophage-like RAW 264 cells, 2) the degradation of 125I-labeled acetylated LDL by RAW 264 cells, and 3) the formation of LDL-derived foam cells in vitro. Liposome-encapsulated clodronate and pamidronate, but not etidronate, decreased the fraction of viable peritoneal macrophages in a concentration-dependent manner, whereas RAW 264 cells were much more resistant to the cytotoxic effects of bisphosphonates. Preincubation with liposomal clodronate and etidronate inhibited in a concentration-dependent manner the degradation of acetylated LDL in RAW 264 cells, but non-cytotoxic concentrations of liposomal pamidronate had only a weak inhibitory effect. The inhibition was more pronounced by liposomal clodronate than by liposomal etidronate. At high concentrations (500 microg protein/ml) of acetylated and aggregated LDL, RAW 264 cells transformed to foam cells. Preincubation with liposomal clodronate and etidronate reduced the cellular accumulation of acetylated LDL-derived lipids, but the drugs had no effect on the lipid accumulation caused by aggregated LDL. The results suggest that liposomal clodronate and etidronate inhibit the activity of phagocyting cells in internalizing and degrading atherogenic modified LDL. PMID:9449231

  11. A Prospective Observational Survey on the Long-Term Effect of LDL Apheresis on Drug-Resistant Nephrotic Syndrome

    PubMed Central

    Muso, Eri; Mune, Masatoshi; Hirano, Tsutomu; Hattori, Motoshi; Kimura, Kenjiro; Watanabe, Tsuyoshi; Yokoyama, Hitoshi; Sato, Hiroshi; Uchida, Shunya; Wada, Takashi; Shoji, Tetsuo; Takemura, Tsukasa; Yuzawa, Yukio; Ogahara, Satoru; Sugiyama, Satoshi; Iino, Yasuhiko; Sakai, Soichi; Ogura, Yousuke; Yukawa, Susumu; Nishizawa, Yoshiki; Yorioka, Noriaki; Imai, Enyu; Matsuo, Seiichi; Saito, Takao

    2015-01-01

    Background/Aims LDL apheresis (LDL-A) is used for drug-resistant nephrotic syndrome (NS) as an alternative therapy to induce remission by improvement of hyperlipidemia. Several clinical studies have suggested the efficacy of LDL-A for refractory NS, but the level of evidence remains insufficient. A multicenter prospective study, POLARIS (Prospective Observational Survey on the Long-Term Effects of LDL Apheresis on Drug-Resistant Nephrotic Syndrome), was conducted to evaluate its clinical efficacy with high-level evidence. Methods Patients with NS who showed resistance to primary medication for at least 4 weeks were prospectively recruited to the study and treated with LDL-A. The long-term outcome was evaluated based on the rate of remission of NS 2 years after treatment. Factors affecting the outcome were also examined. Results A total of 58 refractory NS patients from 40 facilities were recruited and enrolled as subjects of the POLARIS study. Of the 44 subjects followed for 2 years, 21 (47.7%) showed remission of NS based on a urinary protein (UP) level <1.0 g/day. The UP level immediately after LDL-A and the rates of improvement of UP, serum albumin, serum creatinine, eGFR, and total and LDL cholesterol after the treatment session significantly affected the outcome. Conclusions Almost half of the cases of drug-resistant NS showed remission 2 years after LDL-A. Improvement of nephrotic parameters at termination of the LDL-A treatment was a predictor of a favorable outcome. PMID:26557843

  12. Eicosapentaenoic Acid Inhibits Oxidation of ApoB-containing Lipoprotein Particles of Different Size In Vitro When Administered Alone or in Combination With Atorvastatin Active Metabolite Compared With Other Triglyceride-lowering Agents.

    PubMed

    Mason, R Preston; Sherratt, Samuel C R; Jacob, Robert F

    2016-07-01

    Eicosapentaenoic acid (EPA) is a triglyceride-lowering agent that reduces circulating levels of the apolipoprotein B (apoB)-containing lipoprotein particles small dense low-density lipoprotein (sdLDL), very-low-density lipoprotein (VLDL), and oxidized low-density lipoprotein (LDL). These benefits may result from the direct antioxidant effects of EPA. To investigate this potential mechanism, these particles were isolated from human plasma, preincubated with EPA in the absence or presence of atorvastatin (active) metabolite, and subjected to copper-initiated oxidation. Lipid oxidation was measured as a function of thiobarbituric acid reactive substances formation. EPA inhibited sdLDL (IC50 ∼2.0 μM) and LDL oxidation (IC50 ∼2.5 μM) in a dose-dependent manner. Greater antioxidant potency was observed for EPA in VLDL. EPA inhibition was enhanced when combined with atorvastatin metabolite at low equimolar concentrations. Other triglyceride-lowering agents (fenofibrate, niacin, and gemfibrozil) and vitamin E did not significantly affect sdLDL, LDL, or VLDL oxidation compared with vehicle-treated controls. Docosahexaenoic acid was also found to inhibit oxidation in these particles but over a shorter time period than EPA. These data support recent clinical findings and suggest that EPA has direct antioxidant benefits in various apoB-containing subfractions that are more pronounced than those of other triglyceride-lowering agents and docosahexaenoic acid. PMID:26945158

  13. Eicosapentaenoic Acid Inhibits Oxidation of ApoB-containing Lipoprotein Particles of Different Size In Vitro When Administered Alone or in Combination With Atorvastatin Active Metabolite Compared With Other Triglyceride-lowering Agents

    PubMed Central

    Sherratt, Samuel C.R.; Jacob, Robert F.

    2016-01-01

    Abstract: Eicosapentaenoic acid (EPA) is a triglyceride-lowering agent that reduces circulating levels of the apolipoprotein B (apoB)-containing lipoprotein particles small dense low-density lipoprotein (sdLDL), very–low-density lipoprotein (VLDL), and oxidized low-density lipoprotein (LDL). These benefits may result from the direct antioxidant effects of EPA. To investigate this potential mechanism, these particles were isolated from human plasma, preincubated with EPA in the absence or presence of atorvastatin (active) metabolite, and subjected to copper-initiated oxidation. Lipid oxidation was measured as a function of thiobarbituric acid reactive substances formation. EPA inhibited sdLDL (IC50 ∼2.0 μM) and LDL oxidation (IC50 ∼2.5 μM) in a dose-dependent manner. Greater antioxidant potency was observed for EPA in VLDL. EPA inhibition was enhanced when combined with atorvastatin metabolite at low equimolar concentrations. Other triglyceride-lowering agents (fenofibrate, niacin, and gemfibrozil) and vitamin E did not significantly affect sdLDL, LDL, or VLDL oxidation compared with vehicle-treated controls. Docosahexaenoic acid was also found to inhibit oxidation in these particles but over a shorter time period than EPA. These data support recent clinical findings and suggest that EPA has direct antioxidant benefits in various apoB-containing subfractions that are more pronounced than those of other triglyceride-lowering agents and docosahexaenoic acid. PMID:26945158

  14. Effects of magnetic field and Hall current to the blood velocity and LDL transfer

    NASA Astrophysics Data System (ADS)

    Abdullah, I.; Naser, N.; Talib, A. H.; Mahali, S.

    2015-09-01

    The magnetic field and Hall current effects have been considered on blood velocity and concentration of low-density lipoprotein (LDL). It is important to observe those effects to the flowing blood in a stenosed artery. The analysis from the obtained results may be useful to some clinical procedures, such as MRI, where the radiologists may have more information in the investigations before cardiac operations could be done. In this study, the uniform magnetic field and Hall current are applied to the Newtonian blood flow through an artery having a cosine-shaped stenosis. The governing equations are coupled with mass transfer and solved employing a finite difference Marker and Cell (MAC) method with an appropriate initial and boundary conditions. The graphical results of velocity profiles and LDL concentration are presented in this paper and the results show that the velocity increases and concentration decreases as Hall parameter increased.

  15. LDL-lipids from patients with hypercholesterolaemia and Alzheimer's disease are inflammatory to microvascular endothelial cells: mitigation by statin intervention.

    PubMed

    Dias, H K Irundika; Brown, Caroline L R; Polidori, M Cristina; Lip, Gregory Y H; Griffiths, Helen R

    2015-12-01

    Elevated low-density lipoprotein (LDL) concentration in mid-life increases the risk of developing Alzheimer's disease (AD) in later life. Increased oxidized LDL (oxLDL) modification and nitration is observed during dementia and hypercholesterolaemia. We investigated the hypothesis that statin intervention in mid-life mitigates the inflammatory effects of oxLDL on the microvasculature. Human microvascular endothelial cells (HMVECs) were maintained in transwells to mimic the microvasculature and exposed to patient and control LDL. Blood was obtained from statin-naive, normo- and hyper-lipidaemic subjects, AD with vascular dementia (AD-plus) and AD subjects (n=10/group) at baseline. Only hyperlipidaemic subjects with normal cognitive function received 40 mg of simvastatin intervention/day for 3 months. Blood was re-analysed from normo- and hyper-lipidaemic subjects after 3 months. LDL isolated from statin-naive hyperlipidaemic, AD and AD-plus subjects was more oxidized (agarose gel electrophoretic mobility, protein carbonyl content and 8-isoprostane F2α) compared with control subjects. Statin intervention decreased protein carbonyls (2.5±0.4 compared with 3.95±0.2 nmol/mg; P<0.001) and 8-isoprostane F2α (30.4±4.0 pg/ml compared with 43.5±8.42 pg/ml; P<0.05). HMVEC treatment with LDL-lipids (LDL-L) from hyperlipidaemic, AD and AD-plus subjects impaired endothelial tight junction expression and decreased total glutathione levels (AD; 18.61±1.3, AD-plus; 16.5±0.7 nmol/mg of protein) compared with untreated cells (23.8±1.2 compared with nmol/mg of protein). Basolateral interleukin (IL)-6 secretion was increased by LDL-L from hyperlipidaemic (78.4±1.9 pg/ml), AD (63.2±5.9 pg/ml) and AD-plus (80.8±0.9 pg/ml) groups compared with healthy subject lipids (18.6±3.6 pg/ml). LDL-L isolated after statin intervention did not affect endothelial function. In summary, LDL-L from hypercholesterolaemic, AD and AD-plus patients are inflammatory to HMVECs. In vivo

  16. HMGCR rs17671591 SNP Determines Lower Plasma LDL-C after Atorvastatin Therapy in Chilean Individuals.

    PubMed

    Cuevas, Alejandro; Fernández, César; Ferrada, Luis; Zambrano, Tomás; Rosales, Alexy; Saavedra, Nicolás; Salazar, Luis A

    2016-04-01

    Lipid-lowering response to statin therapy shows large interindividual variability. At a genome-wide significance level, single nucleotide polymorphisms (SNPs) in PCSK9 and HMGCR have been implicated in this differential response. However, the influence of these variants is uncertain in the Chilean population. Hence, we aimed to evaluate the contribution of PCSK9 rs7552841 and HMGCR rs17671591 SNPs as genetic determinants of atorvastatin response in Chilean hypercholesterolaemic individuals. One hundred and one hypercholesterolaemic patients received atorvastatin 10 mg/day for 4 weeks. Plasma lipid profile (TC, HDL-C, LDL-C and TG) was determined before and after statin treatment, and SNPs were identified by allelic discrimination using TaqMan(®) SNP Genotyping Assays. Adjusted univariate and multivariate analyses' models were used for statistical analyses, and a p-value <0.05 was considered significant. From baseline (week 0) to the study end-point (week 4), significant reductions were observed in plasma TC, LDL-C and TG (p < 0.001), while HDL-C levels were increased (p < 0.001). Multivariate analysis showed no association between lipid levels and atorvastatin therapy for the PCSK9 variant. However, the HMGCR rs17671591 T allele contributed to basal HDL-C concentration variability along with a higher increase in this lipid fraction after statin medication. In addition, this allele determined greater plasma LDL-C reductions after therapy with atorvastatin. Our data suggest that the HMGCR rs17671591 polymorphism can constitute a genetic marker of lower plasma LDL-C and enhanced HDL-C concentration after atorvastatin therapy in the Chilean population. PMID:26408409

  17. New CETP inhibitor K-312 reduces PCSK9 expression: a potential effect on LDL cholesterol metabolism.

    PubMed

    Miyosawa, Katsutoshi; Watanabe, Yuichiro; Murakami, Kentaro; Murakami, Takeshi; Shibata, Haruki; Iwashita, Masaya; Yamazaki, Hiroyuki; Yamazaki, Koichi; Ohgiya, Tadaaki; Shibuya, Kimiyuki; Mizuno, Ken; Tanabe, Sohei; Singh, Sasha A; Aikawa, Masanori

    2015-07-15

    Despite significant reduction of cardiovascular events by statin treatment, substantial residual risk persists, driving emerging needs for the development of new therapies. We identified a novel cholesteryl ester transfer protein (CETP) inhibitor, K-312, that raises HDL and lowers LDL cholesterol levels in animals. K-312 also suppresses hepatocyte expression of proprotein convertase subtilisin/kexin 9 (PCSK9), a molecule that increases LDL cholesterol. We explored the underlying mechanism for the reduction of PCSK9 expression by K-312. K-312 inhibited in vitro human plasma CETP activity (IC50; 0.06 μM). Administration of K-312 to cholesterol-fed New Zealand White rabbits for 18 wk raised HDL cholesterol, decreased LDL cholesterol, and attenuated aortic atherosclerosis. Our search for additional beneficial characteristics of this compound revealed that K-312 decreases PCSK9 expression in human primary hepatocytes and in the human hepatoma cell line HepG2. siRNA silencing of CETP in HepG2 did not compromise the suppression of PCSK9 by K-312, suggesting a mechanism independent of CETP. In HepG2 cells, K-312 treatment decreased the active forms of sterol regulatory element-binding proteins (SREBP-1 and -2) that regulate promoter activity of PCSK9. Chromatin immunoprecipitation assays demonstrated that K-312 decreased the occupancy of SREBP-1 and SREBP-2 on the sterol regulatory element of the PCSK9 promoter. PCSK9 protein levels decreased by K-312 treatment in the circulating blood of cholesterol-fed rabbits, as determined by two independent mass spectrometry approaches, including the recently developed, highly sensitive parallel reaction monitoring method. New CETP inhibitor K-312 decreases LDL cholesterol and PCSK9 levels, serving as a new therapy for dyslipidemia and cardiovascular disease. PMID:26015437

  18. Xanthine-based KMUP-1 improves HDL via PPARγ/SR-B1, LDL via LDLRs, and HSL via PKA/PKG for hepatic fat loss[S

    PubMed Central

    Kuo, Kung-Kai; Wu, Bin-Nan; Liu, Chung-Pin; Yang, Tzu-Yang; Kao, Li-Pin; Wu, Jiunn-Ren; Lai, Wen-Ter; Chen, Ing-Jun

    2015-01-01

    The phosphodiesterase inhibitor (PDEI)/eNOS enhancer KMUP-1, targeting G-protein coupled receptors (GPCRs), improves dyslipidemia. We compared its lipid-lowering effects with simvastatin and explored hormone-sensitive lipase (HSL) translocation in hepatic fat loss. KMUP-1 HCl (1, 2.5, and 5 mg/kg/day) and simvastatin (5 mg/kg/day) were administered in C57BL/6J male mice fed a high-fat diet (HFD) by gavage for 8 weeks. KMUP-1 inhibited HFD-induced plasma/liver TG, total cholesterol, and LDL; increased HDL/3-hydroxy-3-methylglutaryl-CoA reductase (HMGR)/Rho kinase II (ROCK II)/PPARγ/ABCA1; and decreased liver and body weight. KMUP-1 HCl in drinking water (2.5 mg/200 ml tap water) for 1–14 or 8–14 weeks decreased HFD-induced liver and body weight and scavenger receptor class B type I expression and increased protein kinase A (PKA)/PKG/LDLRs/HSL expression and immunoreactivity. In HepG2 cells incubated with serum or exogenous mevalonate, KMUP-1 (10−7∼10−5 M) reversed HMGR expression by feedback regulation, colocalized expression of ABCA1/apolipoprotein A-I/LXRα/PPARγ, and reduced exogenous geranylgeranyl pyrophosphate/farnesyl pyrophosphate (FPP)-induced RhoA/ROCK II expression. A guanosine 3′,5′-cyclic monophosphate (cGMP) antagonist reversed KMUP-1-induced ROCK II reduction, indicating cGMP/eNOS involvement. KMUP-1 inceased PKG and LDLRs surrounded by LDL and restored oxidized LDL-induced PKA expresion. Unlike simvastatin, KMUP-1 could not inhibit 14C mevalonate formation. KMUP-1 could, but simvastatin could not, decrease ROCK II expression by exogenous FPP/CGPP. KMUP-1 improves HDL via PPARγ/LXRα/ABCA1/Apo-I expression and increases LDLRs/PKA/PKG/HSL expression and immunoreactivity, leading to TG hydrolysis to lower hepatic fat and body weight. PMID:26351364

  19. Lipid fluidity at different regions in LDL and HDL of {beta}-thalassemia/Hb E patients

    SciTech Connect

    Morales, Noppawan Phumala . E-mail: scnpm@mahidol.ac.th; Charlermchoung, Chalermkhwan; Luechapudiporn, Rataya; Yamanont, Paveena; Fucharoen, Suthat; Chantharaksri, Udom

    2006-11-24

    Atherosclerosis-related vascular complications in {beta}-thalassemia/hemoglobin E ({beta}-thal/Hb E) patients may result from iron induced oxidation of lipoproteins. To identify the specific site of oxidative damage, changes in lipid fluidity at different regions in LDL and HDL particle were investigated using two fluorescence probes and two ESR spin probes. The magnitude of increased lipid fluidity in thalassemic lipoproteins was dependent on the location of the probes. In hydrophobic region, the rotational correlation times for 16-doxyl stearic acid and DPH anisotropy were markedly changed in LDL and HDL of the patients. In the surface region, there was only a slight change in the order parameter (S) for 5-doxyl stearic acid and TMA-DPH anisotropy. Lipid fluidity at the core of LDL and HDL showed good correlation with oxidative stress markers, the ratio of CL/CO, and the level of {alpha}-tocopherol, suggesting that hydrophobic region of thalassemic lipoprotein was a target site for oxidative damage.

  20. Sesamol reduces the atherogenicity of electronegative L5 LDL in vivo and in vitro.

    PubMed

    Chen, Wei-Yu; Chen, Fang-Yu; Lee, An-Sheng; Ting, Kuan-Hsiang; Chang, Chia-Ming; Hsu, Jing-Fang; Lee, Wei-Shine; Sheu, Joen-Rong; Chen, Chu-Huang; Shen, Ming-Yi

    2015-02-27

    Highly electronegative low-density lipoprotein (LDL) L5 induces endothelial cell (EC) apoptosis, which leads to the development of atherosclerosis. We examined the effects of sesamol (1), a natural organic component of sesame oil, on plasma L5 levels and atherosclerosis development in a rodent model and on the L5-induced apoptosis of ECs. Syrian hamsters, which have an LDL profile similar to that of humans, were fed a normal chow diet (control), a high-fat diet (HFD), or a HFD supplemented with the administration of 50 or 100 mg/kg of 1 via oral gavage (HFD+1) for 16 weeks (n = 8 per group). Hamsters in the HFD+1 groups had reduced plasma L5 levels when compared with the HFD group. Oil Red O staining showed that atherosclerotic lesion size was markedly reduced in the aortic arch of hamsters in the HFD+1 groups when compared with that in the HFD group. In human aortic ECs, 0.3-3 μM 1 blocked L5-induced apoptosis in a dose-dependent manner. Further mechanistic studies showed that 1 inhibited the L5-induced lectin-like oxidized LDL receptor-1 (LOX-1)-dependent phosphorylation of p38 MAPK and activation of caspase-3 and increased phosphorylation of eNOS and Akt. Our findings suggest that sesamol (1) protects against atherosclerosis by reducing L5-induced atherogenicity. PMID:25692815

  1. Induction of DKK1 by ox-LDL negatively regulates intracellular lipid accumulation in macrophages.

    PubMed

    Zhang, Yu; Ge, Cheng; Wang, Lin; Liu, Xinxin; Chen, Yifei; Li, Mengmeng; Zhang, Mei

    2015-01-01

    Dickkopf1 (DKK1), a canonical Wnt/β-catenin pathway antagonist, is closely associated with cardiovascular disease and adipogenesis. We performed an in vitro study to determine whether oxidized low-density lipoprotein (ox-LDL) increased the expression of DKK1 in macrophages and whether β-catenin and liver X receptor α (LXRα) were involved in this regulation. Induction of DKK1 expression by ox-LDL decreased the level of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) via a Wnt/β-catenin pathway and increased ATP-binding cassette transporter A/G1 (ABCA/G1) levels via a signal transducer and activator of transcription 3 (STAT3) pathway. Lower LOX-1 and higher ABCA/G1 levels inhibited cholesterol loading in macrophages. In conclusion, ox-LDL may induce DKK1 expression in macrophages to inhibit the accumulation of lipids through a mechanism that involves downregulation of LOX-1-mediated lipid uptake and upregulation of ABCA/G1-dependent cholesterol efflux. PMID:25436422

  2. Saikosaponin-a Attenuates Oxidized LDL Uptake and Prompts Cholesterol Efflux in THP-1 Cells.

    PubMed

    He, Dan; Wang, Hongyan; Xu, Ling; Wang, Xiaoqing; Peng, Kuang; Wang, Lili; Liu, Pixu; Qu, Peng

    2016-06-01

    Saikosaponins-a (Ssa) is a major bioactive extract of Radix Bupleuri which is a traditional Chinese medicine. The roles of inflammatory response and lipid transportation in the process of atherosclerosis have drawn increasing attention. We explored the regulation of lipid transportation and immune-inflammatory role of Ssa in early atherosclerosis. The antiatherogenic actions and possible molecular mechanisms of Ssa were texted in THP-1 cells. We examined the effect of Ssa on oxidized low-density lipoprotein (ox-LDL)-induced lipid uptake, cholesterol efflux, immune-inflammatory response. THP-1 macrophages were treated with Ssa followed by ox-LDL for 24 hours. Results from western blot showed that Ssa obviously reduced lipoprotein uptake to block foam cell formation and the expression of Density Lipoprotein Receptor-1 and CD36. Ssa also significantly boosted cholesterol efflux and the expression of ATP binding cassettetransporter A1 and peroxisome proliferator-activated receptor γ. The results also indicated that Ssa inhibited ox-LDL-induced activation of AKT and nuclear factor-κB, assembly of NLRP3 inflammasome and production of proinflammatory cytokines. It is suggested that the ability against immune inflammatory response of Ssa is due to modulation of the PI3K/AKT/NF-κB/NLRP3 pathway. In conclusion, this study provides new insight into Ssa's molecular mechanism and its therapeutic potential in the treatment of atherosclerosis. PMID:26859197

  3. Near Infrared Fluorescence (NIRF) Molecular Imaging of Oxidized LDL with an Autoantibody in Experimental Atherosclerosis

    PubMed Central

    Khamis, Ramzi Y; Woollard, Kevin J.; Hyde, Gareth D.; Boyle, Joseph J; Bicknell, Colin; Chang, Shang-Hung; Malik, Talat H; Hara, Tetsuya; Mauskapf, Adam; Granger, David W; Johnson, Jason L.; Ntziachristos, Vasilis; Matthews, Paul M; Jaffer, Farouc A; Haskard, Dorian O

    2016-01-01

    We aimed to develop a quantitative antibody-based near infrared fluorescence (NIRF) approach for the imaging of oxidized LDL in atherosclerosis. LO1, a well- characterized monoclonal autoantibody that reacts with malondialdehyde-conjugated LDL, was labeled with a NIRF dye to yield LO1-750. LO1-750 specifically identified necrotic core in ex vivo human coronary lesions. Injection of LO1-750 into high fat (HF) fed atherosclerotic Ldlr−/− mice led to specific focal localization within the aortic arch and its branches, as detected by fluorescence molecular tomography (FMT) combined with micro-computed tomography (CT). Ex vivo confocal microscopy confirmed LO1-750 subendothelial localization of LO1-750 at sites of atherosclerosis, in the vicinity of macrophages. When compared with a NIRF reporter of MMP activity (MMPSense-645-FAST), both probes produced statistically significant increases in NIRF signal in the Ldlr−/− model in relation to duration of HF diet. Upon withdrawing the HF diet, the reduction in oxLDL accumulation, as demonstrated with LO1-750, was less marked than the effect seen on MMP activity. In the rabbit, in vivo injected LO1-750 localization was successfully imaged ex vivo in aortic lesions with a customised intra-arterial NIRF detection catheter. A partially humanized chimeric LO1-Fab-Cys localized similarly to the parent antibody in murine atheroma showing promise for future translation. PMID:26911995

  4. Rapamycin down-regulates LDL-receptor expression independently of SREBP-2

    SciTech Connect

    Sharpe, Laura J.; Brown, Andrew J.

    2008-09-05

    As a key regulator of cholesterol homeostasis, sterol-regulatory element binding protein-2 (SREBP-2) up-regulates expression of genes involved in cholesterol synthesis (e.g., 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) Reductase) and uptake (the low density lipoprotein (LDL)-receptor). Previously, we showed that Akt, a critical kinase in cell growth and proliferation, contributes to SREBP-2 activation. However, the specific Akt target involved is unknown. A potential candidate is the mammalian target of rapamycin, mTOR. Rapamycin can cause hyperlipidaemia clinically, and we hypothesised that this may be mediated via an effect of mTOR on SREBP-2. Herein, we found that SREBP-2 activation and HMG-CoA Reductase gene expression were unaffected by rapamycin treatment. However, LDL-receptor gene expression was decreased by rapamycin, suggesting that this may contribute to the hyperlipidaemia observed in rapamycin-treated patients. Rapamycin did not affect mRNA stability, so the decrease in LDL-receptor gene expression is likely to be occurring at the transcriptional level, although independently of SREBP-2.

  5. Degradation of aggregated LDL occurs in complex extracellular sub-compartments of the lysosomal synapse

    PubMed Central

    Singh, Rajesh K.; Barbosa-Lorenzi, Valéria C.; Lund, Frederik W.; Grosheva, Inna; Maxfield, Frederick R.; Haka, Abigail S.

    2016-01-01

    ABSTRACT Monocyte-derived cells use an extracellular, acidic, lytic compartment (a lysosomal synapse) for initial degradation of large objects or species bound to the extracellular matrix. Akin to osteoclast degradation of bone, extracellular catabolism is used by macrophages to degrade aggregates of low density lipoprotein (LDL) similar to those encountered during atherogenesis. However, unlike osteoclast catabolism, the lysosomal synapse is a highly dynamic and intricate structure. In this study, we use high resolution three dimensional imaging to visualize compartments formed by macrophages to catabolize aggregated LDL. We show that these compartments are topologically complex, have a convoluted structure and contain sub-regions that are acidified. These sub-regions are characterized by a close apposition of the macrophage plasma membrane and aggregates of LDL that are still connected to the extracellular space. Compartment formation is dependent on local actin polymerization. However, once formed, compartments are able to maintain a pH gradient when actin is depolymerized. These observations explain how compartments are able to maintain a proton gradient while remaining outside the boundaries of the plasma membrane. PMID:26801085

  6. Low LDL cholesterol in individuals of African descent resulting from frequent nonsense mutations in PCSK9.

    PubMed

    Cohen, Jonathan; Pertsemlidis, Alexander; Kotowski, Ingrid K; Graham, Randall; Garcia, Christine Kim; Hobbs, Helen H

    2005-02-01

    The low-density lipoprotein receptor (LDLR) prevents hypercholesterolemia and atherosclerosis by removing low-density lipoprotein (LDL) from circulation. Mutations in the genes encoding either LDLR or its ligand (APOB) cause severe hypercholesterolemia. Missense mutations in PCSK9, encoding a serine protease in the secretory pathway, also cause hypercholesterolemia. These mutations are probably gain-of-function mutations, as overexpression of PCSK9 in the liver of mice produces hypercholesterolemia by reducing LDLR number. To test whether loss-of-function mutations in PCSK9 have the opposite effect, we sequenced the coding region of PCSK9 in 128 subjects (50% African American) with low plasma levels of LDL and found two nonsense mutations (Y142X and C679X). These mutations were common in African Americans (combined frequency, 2%) but rare in European Americans (<0.1%) and were associated with a 40% reduction in plasma levels of LDL cholesterol. These data indicate that common sequence variations have large effects on plasma cholesterol levels in selected populations. PMID:15654334

  7. Combination effects of wild rice and phytosterols on prevention of atherosclerosis in LDL receptor knockout mice.

    PubMed

    Moghadasian, Mohammed H; Alsaif, Maha; Le, Khuong; Gangadaran, Surendiran; Masisi, Kabo; Beta, Trust; Shen, Garry X

    2016-07-01

    Dietary modifications including healthy eating constitute one of the first line strategies for prevention and treatment of atherosclerotic cardiovascular diseases (CVD), including atherosclerosis. In this study, we assessed anti-atherogenic effects of a combination of wild rice and phytosterols in low-density lipoprotein receptor knockout (LDL-r-KO) mice. Male LDL-r-KO mice were divided into four groups and fed with: (1) control diet; (2) the control diet containing 60% (w/w) wild rice; (3) the control diet containing 2% (w/w) phytosterols; or (4) the control diet containing both wild rice and phytosterols for 20weeks. All diets were supplemented with 0.06% (w/w) dietary cholesterol. Blood samples, hearts, and feces were collected and used for biochemical and histological examination. Consumption of 60% (w/w) wild rice in combination with 2% (w/w) phytosterols significantly reduced the size and severity of atherosclerotic lesions in the aortic roots as compared to those in the control group. This effect was associated with significant reductions in plasma total, LDL and VLDL cholesterol concentrations as well as an increase in fecal cholesterol excretion. In conclusion, the dietary combination of wild rice and phytosterols prevents atherogenesis in this animal model. Further investigations are needed to understand mechanisms of action and potential clinical outcome of such dietary intervention. PMID:27155919

  8. Dietary ellagic acid attenuates oxidized LDL uptake and stimulates cholesterol efflux in murine macrophages.

    PubMed

    Park, Sin-Hye; Kim, Jung-Lye; Lee, Eun-Sook; Han, Seon-Young; Gong, Ju-Hyun; Kang, Min-Kyung; Kang, Young-Hee

    2011-11-01

    Foam cell formation is the hallmark of early atherosclerosis. Lipid uptake by scavenger receptors (SR) in macrophages initiates chronic proinflammatory cascades linked to atherosclerosis. It has been reported that the upregulation of cholesterol efflux may be protective in the development of atherosclerosis. Ellagic acid, a polyphenolic compound mostly found in berries, walnuts, and pomegranates, possesses antioxidative, growth-inhibiting and apoptosis-promoting activities in cancer cells. However, the antiatherogenic actions of ellagic acid are not well defined. The current study elucidated oxidized LDL handling of ellagic acid in J774A1 murine macrophages. Noncytotoxic ellagic acid suppressed SR-B1 induction and foam cell formation within 6 h after the stimulation of macrophages with oxidized LDL, confirmed by Oil red O staining of macrophages. Ellagic acid at ≤5 μmol/L upregulated PPARγ and ATP binding cassette transporter-1 in lipid-laden macrophages, all responsible for cholesterol efflux. In addition, 5 μmol/L ellagic acid accelerated expression and transcription of the nuclear receptor of liver X receptor-α highly implicated in the PPAR signaling. Furthermore, ellagic acid promoted cholesterol efflux in oxidized LDL-induced foam cells. These results provide new information that ellagic acid downregulated macrophage lipid uptake to block foam cell formation of macrophages and boosted cholesterol efflux in lipid-laden foam cells. Therefore, dietary and pharmacological interventions with berries rich in ellagic acid may be promising treatment strategies to interrupt the development of atherosclerosis. PMID:21940512

  9. Hematologic and hemostatic changes induced by different columns during LDL apheresis.

    PubMed

    Hovland, Anders; Hardersen, Randolf; Nielsen, Erik Waage; Mollnes, Tom Eirik; Lappegård, Knut Tore

    2010-01-01

    Low density lipoprotein (LDL) apheresis is a long-term treatment and its impact on risk factors other than lipoproteins could be of importance. Three patients with familial hypercholesterolemia participated in six consecutive treatments with three different LDL apheresis columns in random order: DL-75, LA-15, and EC-50W. We compared treatment effects on hemoglobin, leukocytes, platelets, fibrinogen, thrombin-antithrombin complexes (TAT), plasminogen activator inhibitor-1 (PAI-1), and homocysteine. Hemoglobin, leukocytes and platelets decreased significantly with DL-75 (P < 0.05). Hemoglobin and leukocytes increased significantly with LA-15 and EC-50W (P < 0.05). Platelets were unchanged. The DL-75 column was statistically different from LA-15 and EC-50W regarding these parameters. With the columns DL-75, LA-15, and EC-50W fibrinogen decreased significantly by 28%, 32%, and 42%, PAI-1 decreased significantly by 72%, 58%, and 30% while TAT increased significantly by 138%, 3%, and 251%, respectively (P < 0.05 for all). When comparing the columns there were significant differences between all of them regarding fibrinogen, no differences regarding TAT and a difference between DL-75 and EC-50W regarding PAI-1. With the columns DL-75, LA-15 and EC-50W homocysteine decreased 22%, 9%, and 13%, respectively, but there were no inter column differences. In conclusion, the three LDL apheresis columns affected important hematological and hemostatic risk factors differently. PMID:20806414

  10. Inhibitory Effects of Vinpocetine on the Progression of Atherosclerosis Are Mediated by Akt/NF-κB Dependent Mechanisms in apoE-/- Mice

    PubMed Central

    Zhuang, Jianhui; Peng, Wenhui; Li, Hailing; Lu, Yuyan; Wang, Ke; Fan, Fan; Li, Shuang; Xu, Yawei

    2013-01-01

    Background Recent studies have found additional roles for vinpocetine, a potent phosphodiesterase type I inhibitor, in anti-proliferation and anti-inflammation of vascular smooth muscle cells and cancer cells via different mechanisms. In this study, we attempted to investigate whether vinpocetine protected against atherosclerotic development in apoE-/- mice and explore the underlying anti-atherogenic mechanisms in macrophages. Methodology/Principal Findings Vinpocetine markedly decreased atherosclerotic lesion size in apoE-/- mice measured by oil red O. Masson’s trichrome staining and immunohistochemical analyses revealed that vinpocetine significantly increased the thickness of fibrous cap, reduced the size of lipid-rich necrotic core and attenuated inflammation. In vitro experiments exhibited a significant decrease in monocyte adhesion treated with vinpocetine. Further, active TNF-α, IL-6, monocyte chemoattractant protein-1and matrix metalloproteinase-9 expression induced by ox-LDL were attenuated by vinpocetine in a dose-dependent manner. Similarly, ox-LDL-induced reactive oxygen species were significantly repressed by vinpocetine. Both western blot and luciferase activity assay showed that vinpocetine inhibited the enhanced Akt, IKKα/β, IκBα phosphorylation and NF-κB activity induced by ox-LDL, and the inhibition of NF-κB activity was partly caused by Akt dephosphorylation. However, knockdown of PDE1B did not affect Akt, IKKα/β and IκBα phosphorylation. Conclusions These results suggest that vinpocetine exerts anti-atherogenic effects through inhibition of monocyte adhesion, oxidative stress and inflammatory response, which are mediated by Akt/NF-κB dependent pathway but independent of PDE1 blockade in macrophages. PMID:24349299

  11. Age-dependent dichotomous effect of superoxide dismutase Ala16Val polymorphism on oxidized LDL levels

    PubMed Central

    Kanoni, Stavroula; Panagiotakos, Demosthenes B.; Louizou, Eirini; Grigoriou, Efi; Chrysohoou, Christina; Pitsavos, Christos; Stefanadis, Christodoulos

    2008-01-01

    We investigated the association between superoxide dismutase (SOD) Ala16Val polymorphism and the levels of oxidized LDL lipoprotein-C (ox-LDL-C) in two age-different Greek cohorts. Four hundred fifteen middle-aged (n = 147 females: 43.2 ± 13 years, n = 268 males: 43.3 ± 14 years) Caucasian Greek subjects consisted the middle aged cohort. One hundred seventy five elderly (n = 88 females: 79.9 ± 4 years; n = 87 males: 80.6 ± 4 years) were selected from the elderly cohort. Genotype data were obtained for all of them. Multiple linear regression analysis, stratified by gender and adjusted for age, smoking habits and body mass index as covariates, showed higher ox-LDL-C levels for the middle aged men with the Val/Val genotype, compared to the other allele (Ala/Ala and Ala/Val) carriers (65.9 ± 25.7 vs. 55.7 ± 20.5 mg/dl; standardized β coefficient = 0.192, P = 0.012). On the contrary, elderly women with the Val/Val genotype occurred with lower ox-LDL-C levels compared to the Ala/Ala or Ala/Val genotype (74.2 ± 22.1 vs. 86.5 ± 26.6 mg/dl; standardized β coefficient = -0.269, P = 0.015). The same trend was also recorded in elderly men, however without reaching statistical significance (standardized β coefficient = -0.187, P = 0.077). Moreover, elderly men and women with the Ala/Ala or Ala/Val genotype presented higher triglycerides levels compared to Val/Val (women: 145.2 ± 68.7 vs. 114.3 ± 34.3 mg/dl, P = 0.027; men: 147.8 ± 72.4 vs. 103.7 ± 38.0 mg/dl, P = 0.002). Additionally, middle aged men with the Val/Val genotype had higher HDL-C levels compared to the Ala allele carriers. The results suggest that SOD Ala16Val polymorphism is an age-dependent modulator of ox-LDL-C levels in middle-aged men and elderly women. PMID:18305395

  12. Calpain-1 Mediated Disorder of Pyrophosphate Metabolism Contributes to Vascular Calcification Induced by oxLDL

    PubMed Central

    Lu, Meili; Zhang, Xiaowen; Dai, Chunmei; Mei, Meng; Zhang, Suping; Wang, Hongxin; Song, Qing

    2015-01-01

    We previously reported that oxidized low density lipoprotein (oxLDL) accelerated the calcification in aorta of rats and rat vascular smooth muscle cells (RVSMCs). However, the molecular mechanism underlying the acceleration remains poorly understood. The present study aimed to investigate the role of calpain-1, Ca2+-sensitive intracellular cysteine proteases, in the vascular calcification of rats treated with both high dose of vitamin D2 and high cholesterol diet. The results showed that calpain activity significantly increased in calcified aortic tissue of rats and RVSMCs treated with oxLDL. Specific calpain inhibitor I (CAI, 0.5mg/kg, intraperitoneal) inhibited the vascular calcification in rats with hypercholesterolemia accompanied by the increase in the level of extracellular inorganic pyrophosphate (PPi), the endogenous inhibitor of vascular calcification. In addition, CAI increased the content of adenosine triphosphate (ATP), decreased the activity, mRNA and protein expression of alkaline phosphatase (ALP) and reduced the production of superoxide anion in calcified aortic tissue. CAI also increased the activity of ATP synthase as well as protein expression of ATP5D, δ subunit of ATP synthase. In the in vitro study, suppression of calpain-1 using siRNA assay inhibited the calcium deposition, increased the levels of PPi and ATP, improved the activity of ATP synthase as well as protein expression of ATP5D in RVSMCs treated with oxLDL. Calpain-1 suppression also decreased the activity, mRNA and protein expression of ALP and reduced the mitochondrial ROS (Mito-ROS) production in RVSMCs. However, mito-TEMPO, the mitochondria-targeted ROS scavenger, reduced the calcium deposition, increased the PPi in culture medium, decreased the activity, mRNA and protein expression of ALP in RVSMCs treated with oxLDL. Taken together, the results suggested that calpain-1 activation plays critical role in vascular calcification caused by oxLDL, which might be mediated by PPi

  13. Modifications induced by LDL from type 1 diabetic patients on endothelial cells obtained from human umbilical vein.

    PubMed

    Rabini, R A; Cester, N; Staffolani, R; Salvolini, E; Moretti, N; Vignini, A; Fumelli, D; Mazzanti, L

    1999-11-01

    The aim of the present work was to analyze the effect of LDL obtained from type 1 diabetic patients in good metabolic control on human umbilical vein endothelial cells (HUVECs) after a short incubation period to detect possible atherogenic modifications of endothelial properties. Cultured HUVECs were incubated for 3 h with culture medium alone (control HUVEC), with native LDL from 12 healthy men (control LDL), or with native LDL from 12 type 1 diabetic men (type 1 LDL) (100 pg/ml). After the incubation, the following parameters were evaluated: nitric oxide synthase (NOS) activity, cytoplasmic Ca2+ levels, Na+-K+-ATPase activity, plasma membrane fluidity determined by means of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH), and plasma membrane conjugated diene (CD) content. The same experiments were repeated after bradykinin stimulation or in the presence of the antioxidant butylated hydroxytoluene (BHT), and nitric oxide (NO) production in intact HUVECs was also evaluated. HUVECs incubated with control LDL in comparison with control HUVECs showed a decreased fluidity of the membrane surface evaluated by TMA-DPH and a higher CD content. These alterations were prevented by the presence of BHT. HUVECs incubated with type 1 LDL in comparison with both control HUVECs and cells incubated with control LDL showed 1) increased NOS and Na+-K+-ATPase activity, cytoplasmic Ca2+ levels, and CD content, and 2) decreased fluidity of the membrane surface evaluated by TMA-DPH. These modifications were blunted--but not abolished--by the presence of BHT. After bradykinin stimulation either in the absence or in the presence of BHT, both cytoplasmic Ca2+ levels and NO production were increased in control HUVECs and in HUVECs incubated with control LDL, while a reduced response was observed in HUVECs incubated with type 1 LDL. The alterations observed in the endothelial function after the cell-LDL interaction might play a central

  14. Associations of ApoAI and ApoB-containing Lipoproteins with AngII-induced Abdominal Aortic Aneurysms in Mice

    PubMed Central

    Liu, Jing; Lu, Hong; Howatt, Deborah A.; Balakrishnan, Anju; Moorleghen, Jessica J.; Sorci-Thomas, Mary; Cassis, Lisa A.; Daugherty, Alan

    2015-01-01

    Objective Dyslipidemia is implicated in abdominal aortic aneurysms (AAAs) in humans and angiotensin (Ang)II-infused mice. This study determined effects of major lipoprotein classes on AngII-induced AAAs using multiple mouse strains with dietary and pharmacological manipulations. Approach and Results Western diet had minor effects on plasma cholesterol concentrations and the low incidence of AngII-induced AAAs in C57BL/6J mice. Low incidence of AAAs in this strain was not attributed to protection from HDL, since apolipoprotein (apo)AI deficiency did not increase AngII-induced AAAs. ApoAI deletion also failed to alter AAA occurrence in hypercholesterolemic mice. Low density lipoprotein (LDL) receptor−/− mice fed normal diet had low incidence of AngII-induced AAAs. Western diet feeding of this strain provoked pronounced hypercholesterolemia due to increased apoB-containing lipoproteins with attendant increases of atherosclerosis in both genders, but AAAs only in male mice. ApoE−/− mice fed normal diet were modestly hypercholesterolemic, whereas this strain fed Western diet was severely hypercholesterolemic due to increased apoB-containing lipoprotein concentrations. The latter augmented atherosclerosis, but did not change the high incidence of AAAs in this strain. To determine whether reductions in apoB-containing lipoproteins influenced AngII-induced AAAs, ezetimibe was administered at a dose that partially reduced plasma cholesterol concentrations to apoE−/− mice fed Western diet. This decreased atherosclerosis, but not AAAs. This ezetimibe dose in apoE−/− mice fed normal diet significantly decreased plasma apoB-containing lipoprotein concentrations and reduced AngII-induced AAAs. Conclusions ApoB-containing lipoproteins contribute to augmentation of AngII-induced AAA in male mice. However, unlike atherosclerosis, AAA occurrence was not correlated with increases in plasma apoB-containing lipoprotein concentrations. PMID:26044581

  15. Fluid-phase pinocytosis of LDL by macrophages: a novel target to reduce macrophage cholesterol accumulation in atherosclerotic lesions.

    PubMed

    Kruth, Howar S

    2013-01-01

    Circulating low-density lipoprotein (LDL) that enters the blood vessel wall is the main source of cholesterol that accumulates within atherosclerotic plaques. Much of the deposited cholesterol accumulates within plaque macrophages converting these macrophages into cholesterol-rich foamy looking cells. Cholesterol accumulation in macrophages contributes to cholesterol retention within the vessel wall, and promotes vessel wall inflammation and thrombogenicity. Thus, how macrophages accumulate cholesterol and become foam cells has been the subject of intense investigation. It is generally believed that macrophages accumulate cholesterol only through scavenger receptor-mediated uptake of modified LDL. However, an alternative mechanism for macrophage foam cell formation that does not depend on LDL modification or macrophage receptors has been elucidated. By this alternative mechanism, macrophages show receptor-independent uptake of unmodified native LDL that is mediated by fluid-phase pinocytosis. In receptor-independent, fluid-phase pinocytosis, macrophages take up LDL as part of the fluid that they ingest during micropinocytosis within small vesicles called micropinosomes, and by macropinocytosis within larger vacuoles called macropinosomes. This produces cholesterol accumulation in macrophages to levels characteristic of macrophage foam cells in atherosclerotic plaques. Fluid-phase pinocytosis of LDL is a plausible mechanism that can explain how macrophages accumulate cholesterol and become disease-causing foam cells. Fluid-phase pinocytosis of LDL is a relevant pathway to target for modulating macrophage cholesterol accumulation in atherosclerosis. Recent studies show that phosphoinositide 3-kinase (PI3K), liver X receptors (LXRs), the macrophage colony-stimulating factor (M-CSF) receptor, and protein kinase C (PKC) mediate macrophage macropinocytosis of LDL, and thus, these may be relevant targets to inhibit macrophage cholesterol accumulation in atherosclerosis

  16. MicroRNA-148a regulates LDL receptor and ABCA1 expression to control circulating lipoprotein levels.

    PubMed

    Goedeke, Leigh; Rotllan, Noemi; Canfrán-Duque, Alberto; Aranda, Juan F; Ramírez, Cristina M; Araldi, Elisa; Lin, Chin-Sheng; Anderson, Norma N; Wagschal, Alexandre; de Cabo, Rafael; Horton, Jay D; Lasunción, Miguel A; Näär, Anders M; Suárez, Yajaira; Fernández-Hernando, Carlos

    2015-11-01

    The hepatic low-density lipoprotein receptor (LDLR) pathway is essential for clearing circulating LDL cholesterol (LDL-C). Whereas the transcriptional regulation of LDLR is well characterized, the post-transcriptional mechanisms that govern LDLR expression are just beginning to emerge. Here we develop a high-throughput genome-wide screening assay to systematically identify microRNAs (miRNAs) that regulate LDLR activity in human hepatic cells. From this screen we identified and characterized miR-148a as a negative regulator of LDLR expression and activity and defined a sterol regulatory element-binding protein 1 (SREBP1)-mediated pathway through which miR-148a regulates LDL-C uptake. In mice, inhibition of miR-148a increased hepatic LDLR expression and decreased plasma LDL-C. Moreover, we found that miR-148a regulates hepatic expression of ATP-binding cassette, subfamily A, member 1 (ABCA1) and circulating high-density lipoprotein cholesterol (HDL-C) levels in vivo. These studies uncover a role for miR-148a as a key regulator of hepatic LDL-C clearance through direct modulation of LDLR expression and demonstrate the therapeutic potential of inhibiting miR-148a to ameliorate an elevated LDL-C/HDL-C ratio, a prominent risk factor for cardiovascular disease. PMID:26437365

  17. Marrubium vulgare extract inhibits human-LDL oxidation and enhances HDL-mediated cholesterol efflux in THP-1 macrophage.

    PubMed

    Berrougui, Hicham; Isabelle, Maxim; Cherki, Mounia; Khalil, Abdelouahed

    2006-12-14

    The objective of the present study was to elucidate the beneficial properties of aqueous extracts of Marrubium vulgare (AEM) towards cardiovascular disease by protecting human-LDL against lipid peroxidation and promoting HDL-mediated cholesterol efflux. Human-LDL were oxidised by incubation with CuSO(4) in the presence of increased concentrations of AEM (0-100 microg/ml). LDL lipid peroxidation was evaluated by conjugated diene formation, vitamin E disappearance as well as LDL-electrophoretic mobility. HDL-mediated cholesterol efflux assay was carried out in human THP-1 macrophages. Incubation of LDL with AEM significantly prolonged the lag phase (P=0.014), lowered the progression rate of lipid peroxidation (P=0.004), reduced the disappearance of vitamin E and the electrophoretic mobility in a dose-dependent manner. Also, incubation of HDL with AEM significantly increased HDL-mediated cholesterol efflux from THP-1 macrophages implicating an independent ATP binding cassette A1 (ABCA1) pathways. Our findings suggest that M. vulgare provides a source of natural antioxidants, which inhibit LDL oxidation and enhance reverse cholesterol transport and thus can prevent cardiovascular diseases development. These antioxidant properties increase the anti-atherogenic potential of HDL. PMID:17045616

  18. Oxidized Low-Density Lipoprotein-β2-Glycoprotein I Complex But Not Free Oxidized LDL Is Associated With the Presence and Severity of Coronary Artery Disease.

    PubMed

    Bliden, Kevin P; Chaudhary, Rahul; Lopez, Luis R; Damrongwatanasuk, Rongras; Guyer, Kirk; Gesheff, Martin G; Franzese, Christopher J; Kaza, Himabindu; Tantry, Udaya S; Gurbel, Paul A

    2016-09-01

    Oxidized low-density lipoprotein (oxLDL) and β2-glycoprotein I (β2GPI) have been identified in human atherosclerotic lesions and when complexed have been implicated as a pro-atherothrombotic antigen. We examined the association of free oxLDL and oxLDL-β2GPI complex in patients with coronary artery disease who underwent elective cardiac catheterization. Serum was collected from patients with suspected coronary artery disease immediately before elective cardiac catheterization who were either treated (n = 385) or not treated (n = 150) with statins and from healthy volunteers (n = 134). OxLDL and oxLDL-β2GPI complex levels were determined by enzyme-linked immunosorbent assay. Disease severity was defined angiographically as none-minimal (<20%), moderate (20% to 75%), and severe (>75%) luminal diameter obstruction of any major coronary vessel. Both oxLDL and oxLDL-β2GPI complex were lower in patients on statins (p <0.001). In statin-naive patients, oxLDL-β2GPI complex, but not free oxLDL, was associated with severe coronary artery disease (p = 0.036). However, no association was observed in patients on statins. LDL4 and triglycerides increased with oxLDL-β2GPI complex quartiles (p = 0.001). OxLDL-β2GPI complex (>0.32 U/ml) was predictive of severe atherosclerosis by receiver-operating characteristic curve analysis in statin-naive patients (area under the curve 0.66, p = 0.002). In conclusion, oxLDL-β2GPI appears more predictive of coronary artery disease severity than oxLDL alone in statin-naive patients. PMID:27401271

  19. Hypolipidemic effect of young persimmon fruit in C57BL/6.KOR-ApoEshl mice.

    PubMed

    Matsumoto, Kenji; Yokoyama, Shin-ichiro; Gato, Nobuki

    2008-10-01

    We investigated the hypolipidemic effects of young persimmon fruit (YP) on apolipoprotein E-deficient C57BL/6.KOR-ApoEshl mice. These mice exhibited higher plasma cholesterols, except for high-density lipoprotein (HDL), and lower plasma HDL cholesterol than C57BL/6.Cr mice that had the same genetic background as the C57BL/6.KOR-ApoEshl mice. Male C57BL/6.KOR-ApoEshl mice (n=5) were fed a diet supplemented with dry YP, Hachiya-kaki, at a concentration of 5% (w/w) for 10 weeks. YP treatment significantly lowered plasma chylomicron, very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) cholesterols, and triglyceride, and this response was accompanied by an elevation of fecal bile acid excretion. In the liver, sterol regulatory element binding protein-2 gene expression was significantly higher in mice fed YP, while the mRNA and protein levels of the LDL receptor did not change. These results indicate that acceleration of fecal bile acid excretion is a major mechanism of the hypolipidemic effect induced by YP in C57BL/6.KOR-ApoEshl mice. PMID:18838807

  20. VNN1 promotes atherosclerosis progression in apoE−/− mice fed a high-fat/high-cholesterol diet

    PubMed Central

    Hu, Yan-Wei; Wu, Shao-Guo; Zhao, Jing-Jing; Ma, Xin; Lu, Jing-Bo; Xiu, Jian-cheng; Zhang, Yuan; Huang, Chuan; Qiu, Yu-Rong; Sha, Yan-Hua; Gao, Ji-Juan; Wang, Yan-Chao; Li, Shu-Fen; Zhao, Jia-Yi; Zheng, Lei; Wang, Qian

    2016-01-01

    Accumulated evidence shows that vanin-1 (VNN1) plays a key part in glucose metabolism. We explored the effect of VNN1 on cholesterol metabolism, inflammation, apoptosis in vitro, and progression of atherosclerotic plaques in apoE−/− mice. Oxidized LDL (Ox-LDL) significantly induced VNN1 expression through an ERK1/2/cyclooxygenase-2/PPARα signaling pathway. VNN1 significantly increased cellular cholesterol content and decreased apoAI and HDL-cholesterol (HDL-C)-mediated efflux by 25.16% and 23.13%, respectively, in THP-1 macrophage-derived foam cells (P < 0.05). In addition, VNN1 attenuated Ox-LDL-induced apoptosis through upregulation of expression of p53 by 59.15% and downregulation of expression of B-cell lymphoma-2 127.13% in THP-1 macrophage (P < 0.05). In vivo, apoE−/− mice were divided randomly into two groups and transduced with lentivirus (LV)-Mock or LV-VNN1 for 12 weeks. VNN1-treated mice showed increased liver lipid content and plasma levels of TG (124.48%), LDL-cholesterol (119.64%), TNF-α (148.74%), interleukin (IL)-1β (131.81%), and IL-6 (156.51%), whereas plasma levels of HDL-C (25.75%) were decreased significantly (P < 0.05). Consistent with these data, development of atherosclerotic lesions was increased significantly upon infection of apoE−/− mice with LV-VNN1. These observations suggest that VNN1 may be a promising therapeutic candidate against atherosclerosis. PMID:27281478

  1. Prolyl hydroxylase 3 overexpression accelerates the progression of atherosclerosis in ApoE-/- mice.

    PubMed

    Liu, Hui; Xia, Yanfei; Li, Beibei; Pan, Jinyu; Lv, Mei; Wang, Xuyang; An, Fengshuang

    2016-04-22

    PHD3 belongs to the family of 2-oxoglutarate and iron-dependent dioxygenases and is a critical regulator of HIF-1α. Its expression is increased in cardiovascular diseases such as cardiomyopathy, myocardial ischemia-reperfusion injury, and congestive heart failure. However, the association between PHD3 and atherosclerosis has not been clearly elucidated. In the present study, we investigated the potential effect and mechanism of PHD3 in apolipoprotein E-deficient (ApoE-/-) mice. Murine PHD3 lentivirus and shRNA -PHD3 lentivirus were constructed and injected intravenously into ApoE-/- mice fed on a high fat diet. The aortic atherosclerotic lesion area was larger with PHD3 over-expression. With increased PHD3 levels, macrophages and smooth muscle cells were enhanced. The apoptosis of atherosclerotic plaques revealed an increase when PHD3 was elevated. Furthermore, the expression of intercellular cell adhesion molecule-1(ICAM-1), vascular cell adhesion molecule-1(VCAM-1), monocyte chemotactic protein 1 (MCP-1), interleukin-1beta (IL-1β) and tumor necrosis factor-α(TNF-α) were upregulated with PHD3 over-expression. In vitro, we explored the specific signaling pathway of PHD3 in HUVECs. PHD3 over-expression is associated with activation of ERK1/2 and JNK phosphorylation of MAPK signaling pathway. PHD3 inhibition decreased the apoptosis of HUVECs treated with ox-LDL (50 μg/ml). Our study suggests that PHD3 is not only a regulator of HIF-1α but also an active participant in atherogenesis. PMID:26995088

  2. Emergent Biomarkers of Residual Cardiovascular Risk in Patients with Low HDL-c and/or High Triglycerides and Average LDL-c Concentrations: Focus on HDL Subpopulations, Oxidized LDL, Adiponectin, and Uric Acid

    PubMed Central

    Mascarenhas-Melo, Filipa; Sereno, José; Freitas, Isabel; Isabel-Mendonça, Maria; Pinto, Rui; Teixeira, Frederico

    2013-01-01

    This study intended to determine the impact of HDL-c and/or TGs levels on patients with average LDL-c concentration, focusing on lipidic, oxidative, inflammatory, and angiogenic profiles. Patients with cardiovascular risk factors (n = 169) were divided into 4 subgroups, combining normal and low HDL-c with normal and high TGs patients. The following data was analyzed: BP, BMI, waist circumference and serum glucose, Total-c, TGs, LDL-c, oxidized-LDL, total HDL-c and HDL subpopulations, paraoxonase-1 (PON1) activity, hsCRP, uric acid, TNF-α, adiponectin, VEGF, and iCAM1. The two populations with increased TGs levels, regardless of the normal or low HDL-c, presented obesity and higher waist circumference, Total-c, LDL-c, Ox-LDL, and uric acid. Adiponectin concentration was significantly lower and VEGF was higher in the population with cumulative low values of HDL-c and high values of TGs, while HDL quality was reduced in the populations with impaired values of HDL-c and/or TGs, viewed by reduced large and increased small HDL subfractions. In conclusion, in a population with cardiovascular risk factors, low HDL-c and/or high TGs concentrations seem to be associated with a poor cardiometabolic profile, despite average LDL-c levels. This condition, often called residual risk, is better evidenced by using both traditional and nontraditional CV biomarkers, including large and small HDL subfractions, Ox-LDL, adiponectin, VEGF, and uric acid. PMID:24319364

  3. Endothelial cytoprotection from oxidized LDL by some crude Melanesian plant extracts is not related to their antioxidant capacity.

    PubMed

    Owen, Patrick L; Matainaho, Teatulohi; Sirois, Martin; Johns, Timothy

    2007-01-01

    Habitual consumption of some Melanesian medicinal and food plants may influence atherosclerosis development via their antioxidant capacity at the endothelial level. Areca nut (AN; Areca catechu), piper inflorescence (PBI; Piper betle), betel quid (BQ), guava buds (GB; Psidium guajava), the leaves (NL), juice (NJ), fruit (NF), and root (NR) of noni (Morinda citrifolia), the propagules of raw (MBR), and cooked (MBC) mangrove (Bruguiera gymnorrhiza) were evaluated for their ability to scavenge the 1,1-diphenyl-2-picryl-hydrazyle (DPPH) radical, to protect human low-density lipoprotein (LDL) from Cu2+-catalyzed oxidation and to protect cultured bovine aortal endothelial cells (BAEC) from oxidized LDL (oxLDL)-induced cytotoxicity. Polyphenol-rich extracts AN, PBI, and BQ were potent DPPH scavengers, having similar activity to quercetin and able to protect LDL from oxidation in a dose-dependent manner at concentrations higher than 10 microg/mL, but were pro-oxidants at lower concentrations. These extracts were cytotoxic to BAEC at concentrations above 10 microg/mL and were unable to prevent oxLDL endotheliopathy. GB and NR at 10 mug/mL displayed both the ability to delay LDL oxidation and prevent oxLDL cytotoxicity, although the latter lacked the ability to scavenge the DPPH radical. At higher concentrations, however, both were cytotoxic in themselves. The remaining noni extracts NF, NJ, NL, and both mangrove extracts MBC and MBR were unable to protect LDL from oxidation at all tested concentrations, but were effective cytoprotective agents at 50 microg/mL. All extracts were able to prevent an oxLDL-mediated increase in intracellular aldehyde generation but had little effect on extracellular peroxidation as measured by thiobarbituric acid reactive substances (TBARS). On the basis of this model system, we conclude that the antioxidant benefits of AN, PBI, and BQ may be offset by their enhancement of their cytotoxic effects of oxLDL toward BAEC, whereas GB and low

  4. Simvastatin modulates the heat shock response and cytotoxicity mediated by oxidized LDL in cultured human endothelial smooth muscle cells.

    PubMed

    Pirillo, A; Jacoviello, C; Longoni, C; Radaelli, A; Catapano, A L

    1997-02-13

    Oxidized low density lipoproteins (OxLDL) are toxic to cells of the arterial wall and trigger the expression of the inducible form of hsp 70 in cultured endothelial cells (EAhy-926) and smooth muscle cells (HUVSMC). The latter response is believed to protect cells from toxicity since heat shock protein 70 (hsp70) is synthesized by cells under stress condition to protect proteins from irreversible denaturation. Simvastatin (10(-8) M to 10(-5) M), a competitive inhibitor of hydroxy methyl glutaryl coenzyme A reductase (HMG-CoA reductase), a key enzyme in cholesterol biosynthesis, enhanced the toxicity of OxLDL (300 micrograms/mL) to endothelial cells and smooth muscle cells in a dose-dependent manner, as detected by 3H-adenine release and the MTT test. In EAhy, 3H-adenine release with OxLDL was 0.419 +/- 0.048 (ratio of radioactivity released in the medium to total radioactivity) versus 0.337 +/- 0.008 of control; in the presence of simvastatin and OxLDL this value increased from 0.49 +/- 0.01 at 10(-8) M to 0.918 +/- 0.001 at 10(-5) M with simvastatin alone (10(-5) M) this value was 0.463 +/- 0.025. Furthermore simvastatin reduced in a dose-dependent manner the expression of hsp 70 triggered by OxLDL, as detected by immunoblotting. To address whether this finding was due to the effect of simvastatin on the cholesterol pathway, mevalonate (100 microM) was used to bypass the HMG-CoA reductase block. This compound completely prevented the enhancement of OxLDL toxicity by simvastatin and restored the expression of hsp70. To verify whether cholesterol synthesis was required for the induction of hsp70 by OxLDL, squalestatin I (25 nM to 100 nM), an inhibitor of squalene synthase, another key enzyme of the cholesterol pathway, was used: OxLDL toxicity and hsp70 expression were not affected by this compound. These results indicate that simvastatin increases OxLDL cytotoxicity in vitro with a concomitant decrease of hsp70 expression triggered by OxLDL and that the key step in

  5. Stimulation of LDL receptor activity in Hep-G2 cells by a serum factor(s)

    SciTech Connect

    Ellsworth, J.L.; Brown, C.; Cooper, A.D.

    1988-05-01

    The regulation of low-density lipoprotein (LDL) receptor activity in the human hepatoma cell line Hep-G2 by serum components was examined. Incubation of dense monolayers of Hep-G2 cells with fresh medium containing 10% fetal calf serum (FM) produced a time-dependent increase in LDL receptor activity. Uptake and degradation of 125I-LDL was stimulated two- to four-fold, as compared with that of Hep-G2 cells cultured in the same media in which they had been grown to confluence (CM); the maximal 125I-LDL uptake plus degradation increased from 0.2 microgram/mg cell protein/4 h to 0.8 microgram/mg cell protein/4 h. In addition, a two-fold increase in cell surface binding of 125I-LDL to Hep-G2 cells was observed when binding was measured at 4 degrees C. There was no change in the apparent Kd. The stimulation of LDL receptor activity was suppressed in a concentration-dependent manner by the addition of cholesterol, as LDL, to the cell medium. In contrast to the stimulation of LDL receptor activity, FM did not affect the uptake or degradation of 125I-asialoorosomucoid. Addition of FM increased the protein content per dish, and DNA synthesis was stimulated approximately five-fold, as measured by (3H)thymidine incorporation into DNA; however, the cell number did not change. Cellular cholesterol biosynthesis was also stimulated by FM; (14C)acetate incorporation into unesterified and esterified cholesterol was increased approximately five-fold. Incubation of Hep-G2 cells with high-density lipoproteins (200 micrograms protein/ml) or albumin (8.0 mg/ml) in the absence of the serum factor did not significantly increase the total processed 125I-LDL. Stimulation of LDL receptor activity was dependent on a heat-stable, nondialyzable serum component that eluted in the inclusion volume of a Sephadex G-75 column.

  6. MicroRNAs expression in ox-LDL treated HUVECs: MiR-365 modulates apoptosis and Bcl-2 expression

    SciTech Connect

    Qin, Bing; Xiao, Bo; Liang, Desheng; Xia, Jian; Li, Ye; Yang, Huan

    2011-06-24

    Highlights: {yields} We evaluated the role of miRNAs in ox-LDL induced apoptosis in ECs. {yields} We found 4 up-regulated and 11 down-regulated miRNAs in apoptotic ECs. {yields} Target genes of the dysregulated miRNAs regulate ECs apoptosis and atherosclerosis. {yields} MiR-365 promotes ECs apoptosis via suppressing Bcl-2 expression. {yields} MiR-365 inhibitor alleviates ECs apoptosis induced by ox-LDL. -- Abstract: Endothelial cells (ECs) apoptosis induced by oxidized low-density lipoprotein (ox-LDL) is thought to play a critical role in atherosclerosis. MicroRNAs (miRNAs) are a class of noncoding RNAs that posttranscriptionally regulate the expression of genes involved in diverse cell functions, including differentiation, growth, proliferation, and apoptosis. However, whether miRNAs are associated with ox-LDL induced apoptosis and their effect on ECs is still unknown. Therefore, this study evaluated potential miRNAs and their involvement in ECs apoptosis in response to ox-LDL stimulation. Microarray and qRT-PCR analysis performed on human umbilical vein endothelial cells (HUVECs) exposed to ox-LDL identified 15 differentially expressed (4 up- and 11 down-regulated) miRNAs. Web-based query tools were utilized to predict the target genes of the differentially expressed miRNAs, and the potential target genes were classified into different function categories with the gene ontology (GO) term and KEGG pathway annotation. In particular, bioinformatics analysis suggested that anti-apoptotic protein B-cell CLL/lymphoma 2 (Bcl-2) is a target gene of miR-365, an apoptomir up-regulated by ox-LDL stimulation in HUVECs. We further showed that transfection of miR-365 inhibitor partly restored Bcl-2 expression at both mRNA and protein levels, leading to a reduction of ox-LDL-mediated apoptosis in HUVECs. Taken together, our findings indicate that miRNAs participate in ox-LDL-mediated apoptosis in HUVECs. MiR-365 potentiates ox-LDL-induced ECs apoptosis by regulating the

  7. Genome-wide screen for modulation of hepatic apolipoprotein A-I (ApoA-I) secretion.

    PubMed

    Miles, Rebecca R; Perry, William; Haas, Joseph V; Mosior, Marian K; N'Cho, Mathias; Wang, Jian W J; Yu, Peng; Calley, John; Yue, Yong; Carter, Quincy; Han, Bomie; Foxworthy, Patricia; Kowala, Mark C; Ryan, Timothy P; Solenberg, Patricia J; Michael, Laura F

    2013-03-01

    Control of plasma cholesterol levels is a major therapeutic strategy for management of coronary artery disease (CAD). Although reducing LDL cholesterol (LDL-c) levels decreases morbidity and mortality, this therapeutic intervention only translates into a 25-40% reduction in cardiovascular events. Epidemiological studies have shown that a high LDL-c level is not the only risk factor for CAD; low HDL cholesterol (HDL-c) is an independent risk factor for CAD. Apolipoprotein A-I (ApoA-I) is the major protein component of HDL-c that mediates reverse cholesterol transport from tissues to the liver for excretion. Therefore, increasing ApoA-I levels is an attractive strategy for HDL-c elevation. Using genome-wide siRNA screening, targets that regulate hepatocyte ApoA-I secretion were identified through transfection of 21,789 siRNAs into hepatocytes whereby cell supernatants were assayed for ApoA-I. Approximately 800 genes were identified and triaged using a convergence of information, including genetic associations with HDL-c levels, tissue-specific gene expression, druggability assessments, and pathway analysis. Fifty-nine genes were selected for reconfirmation; 40 genes were confirmed. Here we describe the siRNA screening strategy, assay implementation and validation, data triaging, and example genes of interest. The genes of interest include known and novel genes encoding secreted enzymes, proteases, G-protein-coupled receptors, metabolic enzymes, ion transporters, and proteins of unknown function. Repression of farnesyltransferase (FNTA) by siRNA and the enzyme inhibitor manumycin A caused elevation of ApoA-I secretion from hepatocytes and from transgenic mice expressing hApoA-I and cholesterol ester transfer protein transgenes. In total, this work underscores the power of functional genetic assessment to identify new therapeutic targets. PMID:23322769

  8. Highly electronegative LDL from patients with ST-elevation myocardial infarction triggers platelet activation and aggregation

    PubMed Central

    Chan, Hua-Chen; Ke, Liang-Yin; Chu, Chih-Sheng; Lee, An-Sheng; Shen, Ming-Yi; Cruz, Miguel A.; Hsu, Jing-Fang; Cheng, Kai-Hung; Chan, Hsiu-Chuan Bonnie; Lu, Jonathan; Lai, Wen-Ter; Sawamura, Tatsuya; Sheu, Sheng-Hsiung

    2013-01-01

    Platelet activation and aggregation underlie acute thrombosis that leads to ST-elevation myocardial infarction (STEMI). L5—highly electronegative low-density lipoprotein (LDL)—is significantly elevated in patients with STEMI. Thus, we examined the role of L5 in thrombogenesis. Plasma LDL from patients with STEMI (n = 30) was chromatographically resolved into 5 subfractions (L1-L5) with increasing electronegativity. In vitro, L5 enhanced adenosine diphosphate–stimulated platelet aggregation twofold more than did L1 and induced platelet-endothelial cell (EC) adhesion. L5 also increased P-selectin expression and glycoprotein (GP)IIb/IIIa activation and decreased cyclic adenosine monophosphate levels (n = 6, P < .01) in platelets. In vivo, injection of L5 (5 mg/kg) into C57BL/6 mice twice weekly for 6 weeks shortened tail bleeding time by 43% (n = 3; P < .01 vs L1-injected mice) and increased P-selectin expression and GPIIb/IIIa activation in platelets. Pharmacologic blockade experiments revealed that L5 signals through platelet-activating factor receptor and lectin-like oxidized LDL receptor-1 to attenuate Akt activation and trigger granule release and GPIIb/IIIa activation via protein kinase C-α. L5 but not L1 induced tissue factor and P-selectin expression in human aortic ECs (P < .01), thereby triggering platelet activation and aggregation with activated ECs. These findings indicate that elevated plasma levels of L5 may promote thrombosis that leads to STEMI. PMID:24030386

  9. Genetic variants of ApoE and ApoER2 differentially modulate endothelial function

    PubMed Central

    Ulrich, Victoria; Konaniah, Eddy S.; Herz, Joachim; Gerard, Robert D.; Jung, Eunjeong; Yuhanna, Ivan S.; Ahmed, Mohamed; Hui, David Y.; Mineo, Chieko; Shaul, Philip W.

    2014-01-01

    It is poorly understood why there is greater cardiovascular disease risk associated with the apolipoprotein E4 (apoE) allele vs. apoE3, and also greater risk with the LRP8/apolipoprotein E receptor 2 (ApoER2) variant ApoER2-R952Q. Little is known about the function of the apoE–ApoER2 tandem outside of the central nervous system. We now report that in endothelial cells apoE3 binding to ApoER2 stimulates endothelial NO synthase (eNOS) and endothelial cell migration, and it also attenuates monocyte–endothelial cell adhesion. However, apoE4 does not stimulate eNOS or endothelial cell migration or dampen cell adhesion, and alternatively it selectively antagonizes apoE3/ApoER2 actions. The contrasting endothelial actions of apoE4 vs. apoE3 require the N-terminal to C-terminal interaction in apoE4 that distinguishes it structurally from apoE3. Reconstitution experiments further reveal that ApoER2-R952Q is a loss-of-function variant of the receptor in endothelium. Carotid artery reendothelialization is decreased in ApoER2−/− mice, and whereas adenoviral-driven apoE3 expression in wild-type mice has no effect, apoE4 impairs reendothelialization. Moreover, in a model of neointima formation invoked by carotid artery endothelial denudation, ApoER2−/− mice display exaggerated neointima development. Thus, the apoE3/ApoER2 tandem promotes endothelial NO production, endothelial repair, and endothelial anti-inflammatory properties, and it prevents neointima formation. In contrast, apoE4 and ApoER2-R952Q display dominant-negative action and loss of function, respectively. Thus, genetic variants of apoE and ApoER2 impact cardiovascular health by differentially modulating endothelial function. PMID:25197062

  10. Apple Peel Supplemented Diet Reduces Parameters of Metabolic Syndrome and Atherogenic Progression in ApoE-/- Mice.

    PubMed

    Gonzalez, Jaime; Donoso, Wendy; Sandoval, Nathalie; Reyes, María; Gonzalez, Priscila; Gajardo, Monica; Morales, Erik; Neira, Amalia; Razmilic, Iván; Yuri, José A; Moore-Carrasco, Rodrigo

    2015-01-01

    Cardiovascular Diseases (CVD) represent about 30% of all causes of death worldwide. The development of CVD is related in many cases with the previous existence of metabolic syndrome (MS). It is known that apple consumption has a cardiovascular protecting effect, containing phenolic compounds with antioxidant effect, which are concentrated in the fruit peel. The objective of this study was to test the effect of apple peel consumption in a murine model of MS and apoE-/- mice. Apple supplemented diets reduced the biochemical parameters (glycaemia, total cholesterol, HDL-cholesterol, LDL-cholesterol, ureic nitrogen, triglycerides, insulin, and asymmetric dimethylarginine (ADMA)) of MS model in CF1 mice significantly. The model apoE-/- mouse was used to evaluate the capacity of the apple peel to revert the progression of the atherogenesis. FD with HAP reverts cholesterol significantly and slows down the progression of the plate diminishing the cholesterol accumulation area. With these results, it can be concluded that the consumption of apple peel reduces several MS parameters and the atherogenic progression in mice. PMID:26075004

  11. Chronic hyperbaric oxygen treatment elicits an anti-oxidant response and attenuates atherosclerosis in apoE knockout mice.

    PubMed

    Kudchodkar, Bhalchandra J; Pierce, Anson; Dory, Ladislav

    2007-07-01

    We previously demonstrated that hyperbaric oxygen (HBO) treatment inhibits diet-induced atherosclerosis in New Zealand White rabbits. In the present study we investigate the mechanisms that might be involved in the athero-protective effect of HBO treatment in a well-accepted model of atherosclerosis, the apoE knockout (KO) mouse. We examine the effects of daily HBO treatment (for 5 and 10 weeks) on the components of the anti-oxidant defense mechanism and the redox state in blood, liver and aortic tissues and compare them to those of untreated apoE KO mice. HBO treatment results in a significant reduction of aortic cholesterol content and decreased fatty streak formation. These changes are accompanied by a significant reduction of autoantibodies against oxidatively modified LDL and profound changes in the redox state of the liver and aortic tissues. A 10-week treatment significantly reduces hepatic levels of TBARS and oxidized glutathione, while significantly increases the levels of reduced glutathione, glutathione reductase (GR), transferase, Se-dependent glutathione peroxidase and catalase (CAT). The effects of HBO treatment are similar in the aortic tissues. These observations provide evidence that HBO treatment has a powerful effect on the redox state of relevant tissues and produces an environment that inhibits oxidation. The anti-oxidant response may be the key to the anti-atherogenic effect of HBO treatment. PMID:16973170

  12. Evolocumab (Repatha)--a second PCSK9 inhibitor to lower LDL-Cholesterol.

    PubMed

    2015-10-12

    The second FDA-approved PCSK9 inhibitor evolocumab (Repatha) appears to be similar in efficacy and safety to alirocumab (Praluent), but no comparative studies are available. Given by subcutaneous injection every 2 weeks or once monthly, evolocumab can further lower LDL-cholesterol levels by about 60% in patients at high risk for atherosclerotic cardiovascular disease already taking maximal statin therapy. Its effect on cardiovascular outcomes remains to be established. The long-term efficacy and safety of both evolocumab and alirocumab are unknown, and they are expensive. PMID:26445204

  13. Atorvastatin treatment and LDL cholesterol target attainment in patients at very high cardiovascular risk.

    PubMed

    Laufs, Ulrich; Karmann, Barbara; Pittrow, David

    2016-09-01

    The use of atorvastatin is rapidly increasing among statins since the introduction of generics. However, only limited data are available on its current use and the effectiveness outside of randomised trials. The aim of the study was to assess low-density lipoprotein (LDL-C) levels in ambulatory patients at very high cardiovascular risk on atorvastatin therapy in physician's offices. A total of 2625 high-risk patients on atorvastatin were included into this cross-sectional study by 539 office-based physicians between June and December 2014. 47.0 % of the patients had documented coronary heart disease (CHD), 25.1 % type 2 diabetes mellitus (DM), and 27.9 % CHD plus concomitant DM. The mean age was 66.1 ± 10.8 years, 62.1 % were male. Atorvastatin at the dose of 10, 20, 40 and 80 mg/day was administered in 15.6, 45.7, 33.9, and 4.8 % of the patients, respectively. The treatment duration was 92.6 ± 109.6 weeks. The mean atorvastatin dose at therapy start was 24.8 ± 15.2 mg/day and at time of documentation 27.9 ± 15.8 mg/day. Low-density lipoprotein cholesterol (LDL-C) <70 mg/dL was achieved by 10.5 % of the total cohort (7.5 % in DM, 9.3 % in CHD, and 15.2 % in CHD + DM). In contrast, according to physicians' subjective assessment, 62.7 % of patients (with small differences between groups) had reached their individual LDL-C target. In summary, higher doses of atorvastatin are not frequently used in clinical practice. The LDL-C target level <70 mg/dL as recommended by current guidelines is achieved only in a minority of atorvastatin treated patients at very high cardiovascular risk. PMID:27120330

  14. Taurine protects HK-2 cells from oxidized LDL-induced cytotoxicity via the ROS-mediated mitochondrial and p53-related apoptotic pathways

    SciTech Connect

    Chang, Chun-Yu; Shen, Chao-Yu; Kang, Chao-Kai; Sher, Yuh-Pyng; Sheu, Wayne H.-H.; Chang, Chia-Che; Lee, Tsung-Han

    2014-09-15

    Oxidized LDL (oxLDL) induces a pro-oxidative environment and promotes apoptosis, causing the progression of renal diseases in humans. Taurine is a semi-essential amino acid in mammals and has been shown to be a potent endogenous antioxidant. The kidney plays a pivotal role in maintaining the balance of taurine. However, the mechanisms underlying the protective effects of taurine against oxLDL-induced injury in renal epithelial cells have not been clarified. In the present study, we investigated the anti-apoptotic effects of taurine on human proximal tubular epithelial (HK-2) cells exposed to oxLDL and explored the related mechanisms. We observed that oxLDL increased the contents of ROS and of malondialdehyde (MDA), which is a lipid peroxidation by-product that acts as an indicator of the cellular oxidation status. In addition, oxLDL induced cell death and apoptosis in HK-2 cells. Pretreatment with taurine at 100 μM significantly attenuated the oxLDL-induced cytotoxicity. We determined that oxLDL triggered the phosphorylation of ERK and, in turn, the activation of p53 and other apoptosis-related events, including calcium accumulation, destabilization of the mitochondrial permeability and disruption of the balance between pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins. The malfunctions induced by oxLDL were effectively blocked by taurine. Thus, our results suggested that taurine exhibits potential therapeutic activity by preventing oxLDL-induced nephrotoxicity. The inhibition of oxLDL-induced epithelial apoptosis by taurine was at least partially due to its anti-oxidant activity and its ability to modulate the ERK and p53 apoptotic pathways. - Highlights: • Oxidized LDL induced cytotoxicity and apoptosis in HK-2 cells. • Pretreatment with taurine attenuated oxLDL-induced nephrotoxicity. • Taurine protected against renal damages through inhibition of ROS generation. • Taurine prevented apoptosis through modulation of the p53 phosphorylation.

  15. Nur77 inhibits oxLDL induced apoptosis of macrophages via the p38 MAPK signaling pathway.

    PubMed

    Shao, Qin; Han, Fei; Peng, Shi; He, Ben

    2016-03-18

    The interaction between macrophages and oxLDL plays a crucial role in the initiation and progression of atherosclerosis. As a key initiator in a number of plaque promoting processes, oxLDL induces variable effects such as cell apoptosis or proliferation. Orphan nuclear receptor Nur77 is potently induced in macrophages by diverse stimuli, suggesting that it is of importance in vascular inflammation resulting in atherosclerosis, but whether Nur77 induction is detrimental or protective is unclear. In our study, we explore the role of Nur77 in the regulation of oxLDL-induced macrophage apoptosis and the signaling pathways that are involved. We found that oxLDL induced Nur77 expression in a dose and time dependent fashion, and cell viability was decreased in parallel. To determine whether Nur77 induction contributes to the loss of cell viability or is a protective mechanism, the effect of Nur77 overexpression was examined. Importantly, Nur77 overexpression inhibited the oxLDL-induced decrease of cell viability, inhibited the production of apoptotic bodies and restored DNA synthesis following oxLDL exposure. Furthermore, we found that Nur77 induction is mediated through the p38 MAPK signaling pathway. After pretreatment with SB203580, cell viability was decreased, the expression of CyclinA2 and PCNA was attenuated and the percentage of cell apoptosis was enhanced. Likewise, Nur77 overexpression increased the expression of the cell cycle genes PCNA and p21, and attenuated the increase in caspase-3. On the other hand, knockdown of Nur77 expression by specific siRNA resulted in the increased expression of caspase 3. The results demonstrate that Nur77 is induced by oxLDL via the p38 MAPK signaling pathway, which is involved in the regulation of cell survival. Nur77 enhanced cell survival via suppressing apoptosis, without affecting cell proliferation of activated macrophages, which may be beneficial in patients with atherosclerosis. PMID:26768365

  16. Statin Intensity or Achieved LDL? Practice-based Evidence for the Evaluation of New Cholesterol Treatment Guidelines

    PubMed Central

    Ross, Elsie Gyang

    2016-01-01

    Background The recently updated American College of Cardiology/American Heart Association cholesterol treatment guidelines outline a paradigm shift in the approach to cardiovascular risk reduction. One major change included a recommendation that practitioners prescribe fixed dose statin regimens rather than focus on specific LDL targets. The goal of this study was to determine whether achieved LDL or statin intensity was more strongly associated with major adverse cardiac events (MACE) using practice-based data from electronic health records (EHR). Methods We analyzed the EHR data of more than 40,000 adult patients on statin therapy between 1995 and 2013. Demographic and clinical variables were extracted from coded data and unstructured clinical text. To account for treatment selection bias we performed propensity score stratification as well as 1:1 propensity score matched analyses. Conditional Cox proportional hazards modeling was used to identify variables associated with MACE. Results We identified 7,373 adults with complete data whose cholesterol appeared to be actively managed. In a stratified propensity score analysis of the entire cohort over 3.3 years of follow-up, achieved LDL was a significant predictor of MACE outcome (Hazard Ratio 1.1; 95% confidence interval, 1.05–1.2; P < 0.0004), while statin intensity was not. In a 1:1 propensity score matched analysis performed to more aggressively control for covariate balance between treatment groups, achieved LDL remained significantly associated with MACE (HR 1.3; 95% CI, 1.03–1.7; P = 0.03) while treatment intensity again was not a significant predictor. Conclusions Using EHR data we found that on-treatment achieved LDL level was a significant predictor of MACE. Statin intensity alone was not associated with outcomes. These findings imply that despite recent guidelines, achieved LDL levels are clinically important and LDL titration strategies warrant further investigation in clinical trials. PMID:27227451

  17. Cryptotanshinone inhibits oxidized LDL-induced adhesion molecule expression via ROS dependent NF-κB pathways.

    PubMed

    Zhao, Wenwen; Wu, Chuanhong; Chen, Xiuping

    2016-05-01

    Adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin, play important roles in the initial stage of atherosclerosis. Cryptotanshinone (CPT), a natural compound isolated from Salvia miltiorrhiza Bunge, exhibits anti-atherosclerotic activity although the underlying mechanisms remain elusive. In this study, the protective effect of CPT against oxidized low-density lipoprotein (ox-LDL)-induced adhesion molecule expression was investigated in human umbilical vein endothelial cells. Ox-LDL significantly induced ICAM-1, VCAM-1, and E-selectin expression at the mRNA and protein levels but reduced eNOS phosphorylation and NO generation, which were reversed by CPT pretreatment. Sodium nitroprusside, a NO donor, N-acetyl-L-cysteine (NAC), a reactive oxygen species (ROS) scavenger, and BAY117082, a NF-κB inhibitor, inhibited ox-LDL-induced ICAM-1, VCAM-1, and E-selectin expression. Ox-LDL-induced ROS production was significantly inhibited by CPT and NAC. Furthermore, ox-LDL activated the NF-κB signaling pathway by inducing phosphorylation of IKKβ and IκBα, promoting the interaction of IKKβ and IκBα, and increasing p65 nuclear translocation, which were significantly inhibited by CPT. In addition, CPT, NAC, and BAY117082 inhibited ox-LDL-induced membrane expression of ICAM-1, VCAM-1, E-selectin, and endothelial-monocyte adhesion and restored eNOS phosphorylation and NO generation. Results suggested that CPT inhibited ox-LDL-induced adhesion molecule expression by decreasing ROS and inhibiting the NF-κB pathways, which provides new insight into the anti-atherosclerotic mechanism of CPT. PMID:26647279

  18. Lipidomic changes of LDL in overweight and moderately hypercholesterolemic subjects taking phytosterol- and omega-3-supplemented milk[S

    PubMed Central

    Padro, Teresa; Vilahur, Gemma; Sánchez-Hernández, Joan; Hernández, Marta; Antonijoan, Rosa M.; Perez, Antonio; Badimon, Lina

    2015-01-01

    The benefits of dietary phytosterols (PhySs) and long-chain n-3 PUFA (ω3) have been linked to their effects as cholesterol- and triglyceride (TGL)-lowering agents. However, it remains unknown whether these compounds have further metabolic effects on LDL lipid composition. Here, we studied the effects of PhyS- or ω3-supplemented low-fat milk (milk) on the LDL-lipidome. Overweight and moderately hypercholesterolemic subjects (n = 32) were enrolled in a two-arm longitudinal crossover study. Milk (250 ml/day), enriched with either 1.57 g PhyS or 375 mg ω3 (EPA + DHA), was given to the participants during two sequential 28 day intervention periods. Compared with baseline, PhyS-milk induced a higher reduction in the LDL cholesterol (LDLc) level than ω3-milk. LDL resistance to oxidation was significantly increased after intervention with PhyS-milk. Changes in TGL and VLDL cholesterol were only evident after ω3-milk intake. Lipidomic analysis revealed a differential effect of the PhyS- and ω3-milk interventions on the LDL lipid metabolite pattern. Content in LDL-glycerophospholipids was reduced after PhyS-milk intake, with major changes in phosphatidylcholine (PC) and phosphatidylserine subclasses, whereas ω3-milk induced significant changes in the long-chain polyunsaturated cholesteryl esters and in the ratio PC36:5/lysoPC16:0, associated to a reduced inflammatory activity. In conclusion, daily intake of milk products containing PhyS or ω3 supplements induce changes in the LDL-lipidome that indicate reduced inflammatory and atherogenic effects, beyond their LDLc- and TGL-lowering effects. PMID:25773888

  19. Sorting nexin 17 regulates ApoER2 recycling and reelin signaling.

    PubMed

    Sotelo, Pablo; Farfán, Pamela; Benitez, María Luisa; Bu, Guojun; Marzolo, María-Paz

    2014-01-01

    ApoER2 is a member of the low density-lipoprotein receptor (LDL-R) family. As a receptor for reelin, ApoER2 participates in neuronal migration during development as well as synaptic plasticity and survival in the adult brain. A previous yeast two-hybrid screen showed that ApoER2 is a binding partner of sorting nexin 17 (SNX17) - a cytosolic adaptor protein that regulates the trafficking of several membrane proteins in the endosomal pathway, including LRP1, P-selectin and integrins. However, no further studies have been performed to investigate the role of SNX17 in ApoER2 trafficking and function. In this study, we present evidence based on GST pull-down and inmunoprecipitation assays that the cytoplasmic NPxY endocytosis motif of ApoER2 interacts with the FERM domain of SNX17. SNX17 stimulates ApoER2 recycling in different cell lines including neurons without affecting its endocytic rate and also facilitates the transport of ApoER2 from the early endosomes to the recycling endosomes. The reduction of SNX17 was associated with accumulation of an ApoER2 carboxy-terminal fragment (CTF). In addition, in SNX17 knockdown cells, constitutive ApoER2 degradation was not modified, whereas reelin-induced ApoER2 degradation was increased, implying that SNX17 is a regulator of the receptor's half-life. Finally, in SNX17 silenced hippocampal and cortical neurons, we underscored a positive role of this endosomal protein in the development of the dendritic tree and reelin signaling. Overall, these results establish the role of SNX17 in ApoER2 trafficking and function and aid in identifying new links between endocytic trafficking and receptor signaling. PMID:24705369

  20. Sorting Nexin 17 Regulates ApoER2 Recycling and Reelin Signaling

    PubMed Central

    Sotelo, Pablo; Farfán, Pamela; Benitez, María Luisa; Bu, Guojun; Marzolo, María-Paz

    2014-01-01

    ApoER2 is a member of the low density-lipoprotein receptor (LDL-R) family. As a receptor for reelin, ApoER2 participates in neuronal migration during development as well as synaptic plasticity and survival in the adult brain. A previous yeast two-hybrid screen showed that ApoER2 is a binding partner of sorting nexin 17 (SNX17) - a cytosolic adaptor protein that regulates the trafficking of several membrane proteins in the endosomal pathway, including LRP1, P-selectin and integrins. However, no further studies have been performed to investigate the role of SNX17 in ApoER2 trafficking and function. In this study, we present evidence based on GST pull-down and inmunoprecipitation assays that the cytoplasmic NPxY endocytosis motif of ApoER2 interacts with the FERM domain of SNX17. SNX17 stimulates ApoER2 recycling in different cell lines including neurons without affecting its endocytic rate and also facilitates the transport of ApoER2 from the early endosomes to the recycling endosomes. The reduction of SNX17 was associated with accumulation of an ApoER2 carboxy-terminal fragment (CTF). In addition, in SNX17 knockdown cells, constitutive ApoER2 degradation was not modified, whereas reelin-induced ApoER2 degradation was increased, implying that SNX17 is a regulator of the receptor's half-life. Finally, in SNX17 silenced hippocampal and cortical neurons, we underscored a positive role of this endosomal protein in the development of the dendritic tree and reelin signaling. Overall, these results establish the role of SNX17 in ApoER2 trafficking and function and aid in identifying new links between endocytic trafficking and receptor signaling. PMID:24705369

  1. Students&apos;, Guardians&apos;, and Teachers&apos; Perceptions of Student-Led Conferences

    ERIC Educational Resources Information Center

    Orso, Charlotte Lindsey

    2013-01-01

    The purpose of the study was to examine the ELL and non-ELL students&apos;, guardians&apos;, and the English as a second language (ESL) teachers&apos; perceptions of student-led conferences. Specifically, the study examined if ELL students&apos; and guardians&apos; preferences were similar to non-ELL students&apos; and guardians&apos; preferences…

  2. D-4F reduces EO6 immunoreactivity, SREBP-1c mRNA levels, and renal inflammation in LDL receptor-null mice fed a Western diet.

    PubMed

    Buga, Georgette M; Frank, Joy S; Mottino, Giuliano A; Hakhamian, Ashkan; Narasimha, Ajay; Watson, Andrew D; Yekta, Babak; Navab, Mohamad; Reddy, Srinivasa T; Anantharamaiah, G M; Fogelman, Alan M

    2008-01-01

    LDL receptor-null (LDLR(-/-)) mice on a Western diet (WD) develop endothelial dysfunction and atherosclerosis, which are improved by the apolipoprotein A-I (apoA-I) mimetic peptide D-4F. Focusing on the kidney, LDLR(-/-)mice were fed a WD with D-4F or the inactive control peptide scrambled D-4F (ScD-4F) added to their drinking water. The control mice (ScD-4F) developed glomerular changes, increased immunostaining for MCP-1/CCL2 chemokine, increased macrophage CD68 and F4/80 antigens, and increased oxidized phospholipids recognized by the EO6 monoclonal antibody in both glomerular and tublo-interstitial areas. All of these parameters were significantly reduced by D-4F treatment, approaching levels found in wild-type C57BL/6J or LDLR(-/-) mice fed a chow diet. Sterol-regulatory element binding protein-1c (SREBP-1c) mRNA levels and triglyceride levels were elevated in the kidneys of the control mice (ScD-4F) fed the WD compared with C57BL/6J and LDLR(-/-) mice on chow (P < 0.001 and P < 0.001, respectively) and compared with D-4F-treated mice on the WD (P < 0.01). There was no significant difference in plasma lipids, lipoproteins, glucose, blood pressure, or renal apoB levels between D-4F- and ScD-4F-treated mice. We conclude that D-4F reduced renal oxidized phospholipids, resulting in lower expression of SREBP-1c, which, in turn, resulted in lower triglyceride content and reduced renal inflammation. PMID:17925450

  3. [Differences in Measured Values among Homogenous Assay Reagents of LDL-C in LP-X Positive Serum Samples].

    PubMed

    Abe, Misako; Kurosawa, Hideo; Sato, Ryo; Ito, Kumie; Tomono, Yoshiharu; Manita, Daisuke; Hirowatari, Yuji; Yoshida, Hiroshi

    2015-03-01

    The LDL-C level measures with homogeneous (direct) assays in almost of clinical laboratories. Several reports however showed differences in measured values among the assay reagents. We investigated the differences in LDL-C values among direct assays and Friedewald formula (F-f) in 58 LP-X positive serum samples from jaundice patients by comparing LDL-C values measured by anion-exchange chromatography (AEX-HPLC), largely comparable to ultracentrifugation method. Changes in LDL-C values during the treatment of 8 patients were also investigated. Direct assay reagents from Sekisui Medical (S-r), Denka-Seiken (D-r), Wako Chemical (W-r), and Kyowa Medics (K-r) were used for comparison. F-f, S-r, and D-r correlated with AEX-HPLC with r values < 0.6 while W-r and K-r correlated with AEX-HPLC with r-vales > 0.6. Two samples in which F-f values provided 500 mg/dL plus bias to AEX-HPLC (LDL-C value of 220 mg/dL) demonstrated increased levels of IDL-C before treatment. LDL-C values (S-r and D-r) of the 2 samples were relatively high and near to F-f data while LDL-C values (W-r and K-r) were relatively low and close to AEX-HPLC data. The jaundice treatment decreased LDL-C values (S-r and D-r) and converged to 220 mg/dL, indicating that S-r and D-r might react markedly to IDL. These changes were consistent with decreases in serum free cholesterol and phospholipid in support of LP-X. By contrast, W-r and K-r data showed upward tendency and also converged to 220 mg/dL. These results suggest that LDL-C direct assay reagents would be classified into 2 groups with respect to the reagent reactivity to LP-X. PMID:26524853

  4. A genetic variant in the LDLR promoter is responsible for part of the LDL-cholesterol variability in primary hypercholesterolemia

    PubMed Central

    2014-01-01

    Background GWAS have consistently revealed that LDLR locus variability influences LDL-cholesterol in general population. Severe LDLR mutations are responsible for familial hypercholesterolemia (FH). However, most primary hypercholesterolemias are polygenic diseases. Although Cis-regulatory regions might be the cause of LDL-cholesterol variability; an extensive analysis of the LDLR distal promoter has not yet been performed. We hypothesized that genetic variants in this region are responsible for the LDLR association with LDL-cholesterol found in GWAS. Methods Four-hundred seventy-seven unrelated subjects with polygenic hypercholesterolemia (PH) and without causative FH-mutations and 525 normolipemic subjects were selected. A 3103 pb from LDLR (-625 to +2468) was sequenced in 125 subjects with PH. All subjects were genotyped for 4 SNPs (rs17242346, rs17242739, rs17248720 and rs17249120) predicted to be potentially involved in transcription regulation by in silico analysis. EMSA and luciferase assays were carried out for the rs17248720 variant. Multivariable linear regression analysis using LDL-cholesterol levels as the dependent variable were done in order to find out the variables that were independently associated with LDL-cholesterol. Results The sequencing of the 125 PH subjects did not show variants with minor allele frequency ≥ 10%. The T-allele from g.3131C > T (rs17248720) had frequencies of 9% (PH) and 16.4% (normolipemic), p < 0.00001. Studies of this variant with EMSA and luciferase assays showed a higher affinity for transcription factors and an increase of 2.5 times in LDLR transcriptional activity (T-allele vs C-allele). At multivariate analysis, this polymorphism with the lipoprotein(a) and age explained ≈ 10% of LDL-cholesterol variability. Conclusion Our results suggest that the T-allele at the g.3131 T > C SNP is associated with LDL-cholesterol levels, and explains part of the LDL-cholesterol variability. As a plausible

  5. Circulating CD36 and oxLDL levels are associated with cardiovascular risk factors in young subjects

    PubMed Central

    2014-01-01

    Background Cardiovascular disease (CVD) results from a combination of abnormalities in lipoprotein metabolism, oxidative stress, chronic inflammation, and susceptibility to thrombosis. Atherosclerosis is the major cause of CVD. CD36 has been shown to play a critical role in the development of atherosclerotic lesions by its capacity to bind and promote endocytosis of oxidized low-density lipoprotein (oxLDL) and is implicated in the formation of foam cells. The purpose of this research was to evaluate whether there is an association of sCD36 and oxLDL levels with cardiovascular risk factors in young subjects. Methods A total of 188 subjects, 18 to 25 years old, 133 normal-weight and 55 obese subjects from the state of Guerrero, Mexico were recruited in the study. The lipid profile and glucose levels were measured by enzymatic colorimetric assays. Enzyme-linked immunosorbant assays (ELISA) for oxLDL and sCD36 were performed. Statistical analyses of data were performed with Wilcoxon- Mann Whitney and chi-square tests as well as with multinomial regression. Results TC, LDL-C, TG, oxLDL and sCD36 levels were higher in obese subjects than in normal-weight controls, as well as, monocyte and platelet counts (P < 0.05). Obese subjects had 5.8 times higher risk of sCD36 in the third tertil (>97.8 ng/mL) than normal-weight controls (P = 0.014), and 7.4 times higher risk of oxLDL levels in third tertile (>48 U/L) than control group. The subjects with hypercholesterolemia, hypertriglyceridemia, fasting impaired LDL-C had a higher risk of oxLDL levels in the third tertile (>48 U/L) than the control group (P < 0.05). Conclusions Circulating CD36 and oxLDL levels are associated with cardiovascular risk factors in young subjects and may be potential early markers for cardiovascular disease (CVD). PMID:24766787

  6. Macadamia nut consumption lowers plasma total and LDL cholesterol levels in hypercholesterolemic men.

    PubMed

    Garg, Manohar L; Blake, Robert J; Wills, Ron B H

    2003-04-01

    This study was conducted to assess the cholesterol-lowering potential of macadamia nuts. Seventeen hypercholesterolemic men (mean age 54 y) were given macadamia nuts (40-90 g/d), equivalent to 15% energy intake, for 4 wk. Plasma total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides and homocysteine concentrations and the fatty acid composition of plasma lipids were determined before and after treatment. Plasma MUFA 16:1(n-7), 18:1(n-7) and 20:1(n-9) were elevated after intervention with macadamia nuts. Plasma (n-6) and (n-3) PUFA concentrations were unaffected by macadamia nut consumption. Plasma total cholesterol and LDL cholesterol concentrations decreased by 3.0 and 5.3%, respectively, and HDL cholesterol levels increased by 7.9% in hypercholesterolemic men after macadamia nut consumption. Plasma triglyceride and homocysteine concentrations were not affected by treatment. Macadamia nut consumption was associated with a significant increase in the relative intake of MUFA and a reduced relative intake of saturated fatty acids and PUFA. This study demonstrates that macadamia nut consumption as part of a healthy diet favorably modifies the plasma lipid profile in hypercholesterolemic men despite their diet being high in fat. PMID:12672919

  7. Optimization of LDL targeted nanostructured lipid carriers of 5-FU by a full factorial design

    PubMed Central

    Andalib, Sare; Varshosaz, Jaleh; Hassanzadeh, Farshid; Sadeghi, Hojjat

    2012-01-01

    Background: Nanostructured lipid carriers (NLC) are a mixture of solid and liquid lipids or oils as colloidal carrier systems that lead to an imperfect matrix structure with high ability for loading water soluble drugs. The aim of this study was to find the best proportion of liquid and solid lipids of different types for optimization of the production of LDL targeted NLCs used in carrying 5-Fu by the emulsification-solvent evaporation method. Materials and Methods: The influence of the lipid type, cholesterol or cholesteryl stearate for targeting LDL receptors, oil type (oleic acid or octanol), lipid and oil% on particle size, surface charge, drug loading efficiency, and drug released percent from the NLCs were studied by a full factorial design. Results: The NLCs prepared by 54.5% cholesterol and 25% of oleic acid, showed optimum results with particle size of 105.8 nm, relatively high zeta potential of –25 mV, drug loading efficiency of 38% and release efficiency of about 40%. Scanning electron microscopy of nanoparticles confirmed the results of dynamic light scattering method used in measuring the particle size of NLCs. Conclusions: The optimization method by a full factorial statistical design is a useful optimization method for production of nanostructured lipid carriers. PMID:23326776

  8. Update on lipid-lowering therapy and LDL-cholesterol targets.

    PubMed

    Wiviott, Stephen D; Cannon, Christopher P

    2006-08-01

    Serum cholesterol has long been recognized as an important risk factor for the development and progression of atherosclerotic vascular disease. For more than 30 years, improved outcomes with lipid lowering have been demonstrated. As a result of these data, the National Heart, Lung, and Blood Institute (NHLBI) convened the National Cholesterol Education Program-Adult Treatment Panel I (NCEP ATP I). This panel and similar ones around the world have served to set the standards for lipid lowering in clinical practice. Subsequent revisions of these standards (NCEP ATP II and III) have led to greater focus being placed on LDL, and targets for lowering LDL levels being based on patients' risk of subsequent coronary disease events. Since the publication of the NCEP ATP III guidelines, several large-scale clinical trials of cholesterol lowering have been conducted, the findings of which have the potential to impact on clinical practice standards. In this article we focus on current guidelines for lipid-lowering therapy, review the results and implications of important completed clinical trials, and consider the utility of additional targets for preventive therapy, such as C-reactive protein and HDL. We also consider the prospects for treatments in development and future goals. PMID:16874355

  9. LDL Receptor-Related Protein-1 (LRP1) Regulates Cholesterol Accumulation in Macrophages

    PubMed Central

    Lillis, Anna P.; Muratoglu, Selen Catania; Au, Dianaly T.; Migliorini, Mary; Lee, Mi-Jeong; Fried, Susan K.; Mikhailenko, Irina; Strickland, Dudley K.

    2015-01-01

    Within the circulation, cholesterol is transported by lipoprotein particles and is taken up by cells when these particles associate with cellular receptors. In macrophages, excessive lipoprotein particle uptake leads to foam cell formation, which is an early event in the development of atherosclerosis. Currently, mechanisms responsible for foam cell formation are incompletely understood. To date, several macrophage receptors have been identified that contribute to the uptake of modified forms of lipoproteins leading to foam cell formation, but the contribution of the LDL receptor-related protein 1 (LRP1) to this process is not known. To investigate the role of LRP1 in cholesterol accumulation in macrophages, we generated mice with a selective deletion of LRP1 in macrophages on an LDL receptor (LDLR)-deficient background (macLRP1-/-). After feeding mice a high fat diet for 11 weeks, peritoneal macrophages isolated from Lrp+/+ mice contained significantly higher levels of total cholesterol than those from macLRP1-/- mice. Further analysis revealed that this was due to increased levels of cholesterol esters. Interestingly, macLRP1-/- mice displayed elevated plasma cholesterol and triglyceride levels resulting from accumulation of large, triglyceride-rich lipoprotein particles in the circulation. This increase did not result from an increase in hepatic VLDL biosynthesis, but rather results from a defect in catabolism of triglyceride-rich lipoprotein particles in macLRP1-/- mice. These studies reveal an important in vivo contribution of macrophage LRP1 to cholesterol homeostasis. PMID:26061292

  10. Polymicrobial Oral Infection with Four Periodontal Bacteria Orchestrates a Distinct Inflammatory Response and Atherosclerosis in ApoE null Mice.

    PubMed

    Chukkapalli, Sasanka S; Velsko, Irina M; Rivera-Kweh, Mercedes F; Zheng, Donghang; Lucas, Alexandra R; Kesavalu, Lakshmyya

    2015-01-01

    Periodontal disease (PD) develops from a synergy of complex subgingival oral microbiome, and is linked to systemic inflammatory atherosclerotic vascular disease (ASVD). To investigate how a polybacterial microbiome infection influences atherosclerotic plaque progression, we infected the oral cavity of ApoE null mice with a polybacterial consortium of 4 well-characterized periodontal pathogens, Porphyromonas gingivalis, Treponema denticola, Tannerealla forsythia and Fusobacterium nucleatum, that have been identified in human atherosclerotic plaque by DNA screening. We assessed periodontal disease characteristics, hematogenous dissemination of bacteria, peripheral T cell response, serum inflammatory cytokines, atherosclerosis risk factors, atherosclerotic plaque development, and alteration of aortic gene expression. Polybacterial infections have established gingival colonization in ApoE null hyperlipidemic mice and displayed invasive characteristics with hematogenous dissemination into cardiovascular tissues such as the heart and aorta. Polybacterial infection induced significantly higher levels of serum risk factors oxidized LDL (p < 0.05), nitric oxide (p < 0.01), altered lipid profiles (cholesterol, triglycerides, Chylomicrons, VLDL) (p < 0.05) as well as accelerated aortic plaque formation in ApoE null mice (p < 0.05). Periodontal microbiome infection is associated with significant decreases in Apoa1, Apob, Birc3, Fga, FgB genes that are associated with atherosclerosis. Periodontal infection for 12 weeks had modified levels of inflammatory molecules, with decreased Fas ligand, IL-13, SDF-1 and increased chemokine RANTES. In contrast, 24 weeks of infection induced new changes in other inflammatory molecules with reduced KC, MCSF, enhancing GM-CSF, IFNγ, IL-1β, IL-13, IL-4, IL-13, lymphotactin, RANTES, and also an increase in select inflammatory molecules. This study demonstrates unique differences in the host immune response to a polybacterial periodontal

  11. Intake levels of dietary long-chain PUFAs modify the association between genetic variation in FADS and LDL-C.

    PubMed

    Hellstrand, S; Sonestedt, E; Ericson, U; Gullberg, B; Wirfält, E; Hedblad, B; Orho-Melander, M

    2012-06-01

    Polymorphisms of the FA desaturase (FADS) gene cluster have been associated with LDL, HDL, and triglyceride concentrations. Because FADS converts α-linolenic acid (ALA) and linoleic acid into PUFAs, we investigated the interaction between different PUFA intakes and the FADS polymorphism rs174547 (T>C) on fasting blood lipid and lipoprotein concentrations. We included 4,635 individuals (60% females, 45-68 years) from the Swedish population-based Malmö Diet and Cancer cohort. Dietary intakes were assessed by a modified diet history method including 7-day registration of cooked meals. The C-allele of rs174547 was associated with lower LDL concentration (P = 0.03). We observed significant interaction between rs174547 and long-chain ω-3 PUFA intakes on LDL (P = 0.01); the C-allele was only associated with lower LDL among individuals in the lowest tertile of long-chain ω-3 PUFA intakes (P < 0.001). In addition, significant interaction was observed between rs174547 and the ratio of ALA and linoleic FA intakes on HDL (P = 0.03). However, no significant associations between the C-allele and HDL were detected within the intake tertiles of the ratio. Our findings suggest that dietary intake levels of different PUFAs modify the associated effect of genetic variation in FADS on LDL and HDL. PMID:22451038

  12. A lipidomics study reveals hepatic lipid signatures associating with deficiency of the LDL receptor in a rat model

    PubMed Central

    Quan, Chao; Hu, Chunxiu; Xie, Bingxian; Du, Yinan; Chen, Liang; Yang, Wei; Yang, Liu; Chen, Qiaoli; Shen, Bin; Hu, Bian; Zheng, Zhihong; Zhu, Haibo; Huang, Xingxu; Xu, Guowang; Chen, Shuai

    2016-01-01

    ABSTRACT The low-density lipoprotein receptor (LDLR) plays a critical role in the liver for the clearance of plasma low-density lipoprotein (LDL). Its deficiency causes hypercholesterolemia in many models. To facilitate the usage of rats as animal models for the discovery of cholesterol-lowering drugs, we took a genetic approach to delete the LDLR in rats aiming to increase plasma LDL cholesterol (LDL-C). An LDLR knockout rat was generated via zinc-finger nuclease technology, which harbors a 19-basepair deletion in the seventh exon of the ldlr gene. As expected, deletion of the LDLR elevated total cholesterol and total triglyceride in the plasma, and caused a tenfold increase of plasma LDL-C and a fourfold increase of plasma very low-density lipoprotein (VLDL-C). A lipidomics analysis revealed that deletion of the LDLR affected hepatic lipid metabolism, particularly lysophosphatidylcholines, free fatty acids and sphingolipids in the liver. Cholesterol ester (CE) 20:4 also displayed a significant increase in the LDLR knockout rats. Taken together, the LDLR knockout rat offers a new model of hypercholesterolemia, and the lipidomics analysis reveals hepatic lipid signatures associating with deficiency of the LDL receptor. PMID:27378433

  13. Puerarin Inhibits oxLDL-Induced Macrophage Activation and Foam Cell Formation in Human THP1 Macrophage.

    PubMed

    Zhang, Heng; Zhai, Zhenhua; Zhou, Hongyu; Li, Yao; Li, Xiaojie; Lin, Yuhan; Li, Weihong; Shi, Yueping; Zhou, Ming-Sheng

    2015-01-01

    Puerarin, an isoflavone derived from Kudzu roots, has been widely used for treatment of cardiovascular and cerebral vascular diseases in China and other Asian countries. However, the underlying mechanisms are largely unknown. The present study investigated whether puerarin inhibited atherogenic lipid oxLDL-mediated macrophage activation and foam cell formation in human THP1 macrophage. Treatment with oxLDL significantly increased the mRNA expression of proinflammatory cytokines tumor necrosis factor α (TNFα, 160%) and interleukin (IL) 1β (13 fold) accompanied by upregulation of toll-like receptor 4 (TLR4, 165%) and the ratio of phospho-IκBα/IκBα in THP1 macrophage. Puerarin dose-dependently prevented an increase in oxLDL-induced proinflammatory gene expression with downregulation of TLR4 and the ratio of phospho-IκBα/IκBα. Furthermore, puerarin prevented oxLDL-mediated lipid deposition and foam cell formation associated with downregulation of scavenger receptor CD36. Flow cytometry analysis showed that puerarin reduced the number of early apoptotic cells of macrophages induced by oxLDL. Our results show that puerarin has anti-inflammatory and antiatherogenic effects in vitro; the underlying mechanisms may involve the inhibition of TLR4/NFκB pathway and downregulation of CD36 expression. The results from the present study provide scientific evidence and may expand our armamentarium to use puerarin for prevention and treatment of cardiovascular and atherosclerotic diseases. PMID:26576421

  14. Protocatechuic Acid Prevents oxLDL-Induced Apoptosis by Activating JNK/Nrf2 Survival Signals in Macrophages

    PubMed Central

    Varì, Rosaria; Scazzocchio, Beatrice; Santangelo, Carmela; Filesi, Carmelina; Galvano, Fabio; D'Archivio, Massimo; Masella, Roberta; Giovannini, Claudio

    2015-01-01

    Protocatechuic acid (PCA), one of the main metabolites of complex polyphenols, exerts numerous biological activities including antiapoptotic, anti-inflammatory, and antiatherosclerotic effects. Oxidised LDL have atherogenic properties by damaging arterial wall cells and inducing p53-dependent apoptosis in macrophages. This study was aimed at defining the molecular mechanism responsible for the protective effects of PCA against oxidative and proapoptotic damage exerted by oxLDL in J774 A.1 macrophages. We found that the presence of PCA in cells treated with oxLDL completely inhibited the p53-dependent apoptosis induced by oxLDL. PCA decreased oxLDL-induced ROS overproduction and in particular prevented the early increase of ROS. This decrease seemed to be the main signal responsible for maintaining the intracellular redox homeostasis hindering the activation of p53 induced by ROS, p38MAPK, and PKCδ. Consequently the overexpression of the proapoptotic p53-target genes such as p66Shc protein did not occur. Finally, we demonstrated that PCA induced the activation of JNK, which, in turn, determined the increase of nuclear Nrf2, leading to inhibition of the early ROS overproduction. We concluded that the antiapoptotic mechanism of PCA was most likely related to the activation of the JNK-mediated survival signals that strengthen the cellular antioxidant defences rather than to the PCA antioxidant power. PMID:26180584

  15. Lectin-Like Oxidized LDL Receptor-1 Is an Enhancer of Tumor Angiogenesis in Human Prostate Cancer Cells

    PubMed Central

    González-Chavarría, Iván; Cerro, Rita P.; Parra, Natalie P.; Sandoval, Felipe A.; Zuñiga, Felipe A.; Omazábal, Valeska A.; Lamperti, Liliana I.; Jiménez, Silvana P.; Fernandez, Edelmira A.; Gutiérrez, Nicolas A.; Rodriguez, Federico S.; Onate, Sergio A.; Sánchez, Oliberto; Vera, Juan C.; Toledo, Jorge R.

    2014-01-01

    Altered expression and function of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) has been associated with several diseases such as endothelial dysfunction, atherosclerosis and obesity. In these pathologies, oxLDL/LOX-1 activates signaling pathways that promote cell proliferation, cell motility and angiogenesis. Recent studies have indicated that olr1 mRNA is over-expressed in stage III and IV of human prostatic adenocarcinomas. However, the function of LOX-1 in prostate cancer angiogenesis remains to be determined. Our aim was to analyze the contribution of oxLDL and LOX-1 to tumor angiogenesis using C4-2 prostate cancer cells. We analyzed the expression of pro-angiogenic molecules and angiogenesis on prostate cancer tumor xenografts, using prostate cancer cell models with overexpression or knockdown of LOX-1 receptor. Our results demonstrate that the activation of LOX-1 using oxLDL increases cell proliferation, and the expression of the pro-angiogenic molecules VEGF, MMP-2, and MMP-9 in a dose-dependent manner. Noticeably, these effects were prevented in the C4-2 prostate cancer model when LOX-1 expression was knocked down. The angiogenic effect of LOX-1 activated with oxLDL was further demonstrated using the aortic ring assay and the xenograft model of tumor growth on chorioallantoic membrane of chicken embryos. Consequently, we propose that LOX-1 activation by oxLDL is an important event that enhances tumor angiogenesis in human prostate cancer cells. PMID:25170920

  16. Protocatechuic Acid Prevents oxLDL-Induced Apoptosis by Activating JNK/Nrf2 Survival Signals in Macrophages.

    PubMed

    Varì, Rosaria; Scazzocchio, Beatrice; Santangelo, Carmela; Filesi, Carmelina; Galvano, Fabio; D'Archivio, Massimo; Masella, Roberta; Giovannini, Claudio

    2015-01-01

    Protocatechuic acid (PCA), one of the main metabolites of complex polyphenols, exerts numerous biological activities including antiapoptotic, anti-inflammatory, and antiatherosclerotic effects. Oxidised LDL have atherogenic properties by damaging arterial wall cells and inducing p53-dependent apoptosis in macrophages. This study was aimed at defining the molecular mechanism responsible for the protective effects of PCA against oxidative and proapoptotic damage exerted by oxLDL in J774 A.1 macrophages. We found that the presence of PCA in cells treated with oxLDL completely inhibited the p53-dependent apoptosis induced by oxLDL. PCA decreased oxLDL-induced ROS overproduction and in particular prevented the early increase of ROS. This decrease seemed to be the main signal responsible for maintaining the intracellular redox homeostasis hindering the activation of p53 induced by ROS, p38MAPK, and PKCδ. Consequently the overexpression of the proapoptotic p53-target genes such as p66Shc protein did not occur. Finally, we demonstrated that PCA induced the activation of JNK, which, in turn, determined the increase of nuclear Nrf2, leading to inhibition of the early ROS overproduction. We concluded that the antiapoptotic mechanism of PCA was most likely related to the activation of the JNK-mediated survival signals that strengthen the cellular antioxidant defences rather than to the PCA antioxidant power. PMID:26180584

  17. A lipidomics study reveals hepatic lipid signatures associating with deficiency of the LDL receptor in a rat model.

    PubMed

    Wang, Hong Yu; Quan, Chao; Hu, Chunxiu; Xie, Bingxian; Du, Yinan; Chen, Liang; Yang, Wei; Yang, Liu; Chen, Qiaoli; Shen, Bin; Hu, Bian; Zheng, Zhihong; Zhu, Haibo; Huang, Xingxu; Xu, Guowang; Chen, Shuai

    2016-01-01

    The low-density lipoprotein receptor (LDLR) plays a critical role in the liver for the clearance of plasma low-density lipoprotein (LDL). Its deficiency causes hypercholesterolemia in many models. To facilitate the usage of rats as animal models for the discovery of cholesterol-lowering drugs, we took a genetic approach to delete the LDLR in rats aiming to increase plasma LDL cholesterol (LDL-C). An LDLR knockout rat was generated via zinc-finger nuclease technology, which harbors a 19-basepair deletion in the seventh exon of the ldlr gene. As expected, deletion of the LDLR elevated total cholesterol and total triglyceride in the plasma, and caused a tenfold increase of plasma LDL-C and a fourfold increase of plasma very low-density lipoprotein (VLDL-C). A lipidomics analysis revealed that deletion of the LDLR affected hepatic lipid metabolism, particularly lysophosphatidylcholines, free fatty acids and sphingolipids in the liver. Cholesterol ester (CE) 20:4 also displayed a significant increase in the LDLR knockout rats. Taken together, the LDLR knockout rat offers a new model of hypercholesterolemia, and the lipidomics analysis reveals hepatic lipid signatures associating with deficiency of the LDL receptor. PMID:27378433

  18. Plasma ApoC-III Levels, Triglycerides, and Coronary Artery Calcification in Type 2 Diabetics

    PubMed Central

    Qamar, Arman; Khetarpal, Sumeet A.; Khera, Amit V.; Qasim, Atif; Rader, Daniel J.; Reilly, Muredach P.

    2015-01-01

    Objective Triglyceride-rich lipoproteins (TRL) have emerged as causal risk factors for developing coronary heart disease (CHD) independent of low-density lipoprotein cholesterol (LDL-C) levels. Apolipoprotein C-III (ApoC-III) modulates TRL metabolism through inhibition of lipoprotein lipase and hepatic uptake of TRL. Mutations causing loss-of-function of ApoC-III lower TG and reduce CHD risk, suggestive of a causal role for ApoC-III. Little data exist regarding the relationship of ApoC-III, TG, and atherosclerosis in type 2 diabetes mellitus (T2DM) patients. Here, we examined the relationships between plasma ApoC-III, TG and coronary artery calcification (CAC) in T2DM patients. Approach & Results Plasma ApoC-III levels were measured in a cross-sectional study of 1422 subjects with T2DM but without clinically manifest CHD. ApoC-III levels were positively associated with total cholesterol (Spearman r=0.36), TG (r=0.59), LDL-C (r=0.16), fasting glucose (r=0.16) and glycosylated hemoglobin (r=0.12) (P < 0.0001 for all). In age, gender, and race-adjusted analysis, ApoC-III levels were positively associated with CAC (Tobit regression ratio (TRR) 1.78, 95% CI 1.27–2.50 per SD-increase in ApoC-III, P <0.001). As expected for an intermediate mediator, these findings were attenuated when adjusted for both TG (TRR 1.43, 95% CI 0.94–2.18, P=0.086) and separately for VLDL-C (TRR 1.14, 95% ci 0.75–1.71, P=0.53). Conclusions In persons with T2DM, increased plasma ApoC-III is associated with higher TG, less favorable cardiometabolic phenotypes, and higher CAC, a measure of subclinical atherosclerosis. Therapeutic inhibition of ApoC-III may thus be a novel strategy for reducing plasma TRLs and cardiovascular risk in T2DM. PMID:26069232

  19. Inhibition of intestinal absorption of cholesterol by ezetimibe or bile acids by SC-435 alters lipoprotein metabolism and extends the lifespan of SR-BI/apoE double knockout mice.

    PubMed

    Braun, Anne; Yesilaltay, Ayce; Acton, Susan; Broschat, Kay O; Krul, Elaine S; Napawan, Nida; Stagliano, Nancy; Krieger, Monty

    2008-05-01

    SR-BI/apoE double knockout (dKO) mice exhibit many features of human coronary heart disease (CHD), including hypercholesterolemia, occlusive coronary atherosclerosis, cardiac hypertrophy, myocardial infarctions, cardiac dysfunction and premature death. Ezetimibe is a FDA-approved, intestinal cholesterol absorption inhibitor that lowers plasma LDL cholesterol in humans and animals and inhibits aortic root atherosclerosis in apoE KO mice, but has not been proven to reduce CHD. Three-week-ezetimibe treatment of dKO mice (0.005% (w/w) in standard chow administered from weaning) resulted in a 35% decrease in cholesterol in IDL/LDL-size lipoproteins, but not in VLDL- and HDL-size lipoproteins. Ezetimibe treatment significantly reduced aortic root (57%) and coronary arterial (68%) atherosclerosis, cardiomegaly (24%) and cardiac fibrosis (57%), and prolonged the lives of the mice (27%). This represents the first demonstration of beneficial effects of ezetimibe treatment on CHD. The dKO mice were similarly treated with SC-435 (0.01% (w/w)), an apical sodium codependent bile acid transporter (ASBT) inhibitor, that blocks intestinal absorption of bile acids, lowers plasma cholesterol in animals, and reduces aortic root atherosclerosis in apoE KO mice. The effects of SC-435 treatment were similar to those of ezetimibe: 37% decrease in ILD/LDL-size lipoprotein cholesterol and 57% prolongation in median lifespan. Thus, inhibition of intestinal absorption of either cholesterol (ezetimibe) or bile acids (SC-435) significantly reduced plasma IDL/LDL-size lipoprotein cholesterol levels and improved survival of SR-BI/apoE dKO mice. The SR-BI/apoE dKO murine model of atherosclerotic occlusive, arterial CHD appears to provide a useful system to evaluate compounds that modulate cholesterol homeostasis and atherosclerosis. PMID:18054357

  20. Serum Oxidized LDL Levels in Type 2 Diabetic Patients with Retinopathy in Mthatha Region of the Eastern Cape Province of South Africa

    PubMed Central

    2016-01-01

    Oxidized low-density lipoprotein (ox-LDL) is a powerful natural prooxidant derived from native LDL by cell-mediated oxidation. Such oxidation occurs more easily in glycated LDL as observed in diabetes mellitus. We evaluated and compared selected biomarkers of oxidative stress and total antioxidant (TAO) levels in type 2 diabetes mellitus (T2DM) patients with and without retinopathy in the Mthatha region of the Eastern Cape Province, South Africa. The participants totaled to 140 and this number comprised 98 diabetic patients on treatment, stratified by diabetes (54) and diabetes with retinopathy (44). Forty-two nondiabetic healthy controls made up the 140. Fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), lipid profile, serum ox-LDL, thiobarbituric acid reactive substances (TBARS), and TAO levels were measured. A statistically significant increase in FPG, HbA1c, TBARS, and ox-LDL and a significant decrease in TAO levels were seen in T2DM patients with retinopathy as compared to controls. A significant negative correlation was observed between TAO and ox-LDL levels in the diabetic group. In multiple linear regression analyses, duration of diabetes, triglyceride, TAO, and LDL cholesterol were found to be significantly associated with ox-LDL. In multiple logistic regression analyses, ox-LDL [OR 1.02 (1.01–1.03), P = 0.005] was the only risk factor and was significantly associated with the presence of retinopathy. PMID:27433285

  1. The Spacing between Cysteines Two and Three of the LDL-A Module of Tva Is Important for Subgroup A Avian Sarcoma and Leukosis Virus Entry

    PubMed Central

    Rai, Tia; Marble, Deborah; Rihani, Kayla; Rong, Lijun

    2004-01-01

    Rong et al. have demonstrated previously that with a few substitutions, the fourth repeat of human low-density lipoprotein (hLDL-A4) receptor can functionally replace the LDL-A module of Tva, the cellular receptor for subgroup A avian sarcoma and leukosis virus (ASLV-A), in viral entry (L. Rong, K. Gendron, and P. Bates, Proc. Natl. Acad. Sci. USA 95:8467-8472, 1998). Here we have shown that swapping the amino terminus of hLDL repeat 5 (hLDL-A5) with that of Tva, in addition to the corresponding substitutions made in human LDL-A4, was required to convert hLDL-A5 into an efficient ASLV-A receptor. These results substantiated our previous findings regarding the role of the specific residues in the viral interaction domain of Tva and demonstrated the critical role of the amino terminus of the Tva LDL-A module in ASLV-A infection. Furthermore, we have shown that the residues between cysteines 2 and 3 of the Tva LDL-A module in a Tva/LDL-A5 chimeric protein can be functionally replaced by the corresponding region of another LDL-A module, human LDL receptor-related protein repeat 22 (LDL-A22), to mediate efficient ASLV-A entry. Since the only conserved feature between the C2-C3 region of LDL-A22 and the Tva LDL-A module is that both contain nine amino acids of which none are conserved, we conclude that the spacing between C2 and C3 of the LDL-A module of Tva is an important determinant for ASLV-A entry. Thus, the present study provides strong evidence to support our hypothesis that one role of the N terminus of the LDL-A module of Tva is to allow proper folding and conformation of the protein for optimal interaction with the viral glycoprotein EnvA in ASLV-A entry. PMID:14694099

  2. The spacing between cysteines two and three of the LDL-A module of Tva is important for subgroup A avian sarcoma and leukosis virus entry.

    PubMed

    Rai, Tia; Marble, Deborah; Rihani, Kayla; Rong, Lijun

    2004-01-01

    Rong et al. have demonstrated previously that with a few substitutions, the fourth repeat of human low-density lipoprotein (hLDL-A4) receptor can functionally replace the LDL-A module of Tva, the cellular receptor for subgroup A avian sarcoma and leukosis virus (ASLV-A), in viral entry (L. Rong, K. Gendron, and P. Bates, Proc. Natl. Acad. Sci. USA 95:8467-8472, 1998). Here we have shown that swapping the amino terminus of hLDL repeat 5 (hLDL-A5) with that of Tva, in addition to the corresponding substitutions made in human LDL-A4, was required to convert hLDL-A5 into an efficient ASLV-A receptor. These results substantiated our previous findings regarding the role of the specific residues in the viral interaction domain of Tva and demonstrated the critical role of the amino terminus of the Tva LDL-A module in ASLV-A infection. Furthermore, we have shown that the residues between cysteines 2 and 3 of the Tva LDL-A module in a Tva/LDL-A5 chimeric protein can be functionally replaced by the corresponding region of another LDL-A module, human LDL receptor-related protein repeat 22 (LDL-A22), to mediate efficient ASLV-A entry. Since the only conserved feature between the C2-C3 region of LDL-A22 and the Tva LDL-A module is that both contain nine amino acids of which none are conserved, we conclude that the spacing between C2 and C3 of the LDL-A module of Tva is an important determinant for ASLV-A entry. Thus, the present study provides strong evidence to support our hypothesis that one role of the N terminus of the LDL-A module of Tva is to allow proper folding and conformation of the protein for optimal interaction with the viral glycoprotein EnvA in ASLV-A entry. PMID:14694099

  3. Metformin regulates oxLDL-facilitated endothelial dysfunction by modulation of SIRT1 through repressing LOX-1-modulated oxidative signaling.

    PubMed

    Hung, Ching-Hsia; Chan, Shih-Hung; Chu, Pei-Ming; Lin, Huei-Chen; Tsai, Kun-Ling

    2016-03-01

    It is suggested that oxLDL is decisive in the initiation and development of atherosclerotic injuries. The up-regulation of oxidative stress and the generation of ROS act as key modulators in developing pro-atherosclerotic and anti-atherosclerotic processes in the human endothelial wall. In this present study, we confirmed that metformin enhanced SIRT1 and AMPK expression in human umbilical vein endothelial cells (HUVECs). Metformin also inhibited oxLDL-increased LOX-1 expression and oxLDL-collapsed AKT/eNOS levels. However, silencing SIRT1 and AMPK diminished the protective function of metformin against oxidative injuries. These results provide a new insight regarding the possible molecular mechanisms of metformin. PMID:26885898

  4. Metformin regulates oxLDL-facilitated endothelial dysfunction by modulation of SIRT1 through repressing LOX-1-modulated oxidative signaling

    PubMed Central

    Hung, Ching-Hsia; Chan, Shih-Hung; Chu, Pei-Ming; Lin, Huei-Chen; Tsai, Kun-Ling

    2016-01-01

    It is suggested that oxLDL is decisive in the initiation and development of atherosclerotic injuries. The up-regulation of oxidative stress and the generation of ROS act as key modulators in developing pro-atherosclerotic and anti-atherosclerotic processes in the human endothelial wall. In this present study, we confirmed that metformin enhanced SIRT1 and AMPK expression in human umbilical vein endothelial cells (HUVECs). Metformin also inhibited oxLDL-increased LOX-1 expression and oxLDL-collapsed AKT/eNOS levels. However, silencing SIRT1 and AMPK diminished the protective function of metformin against oxidative injuries. These results provide a new insight regarding the possible mol