Proteomic analysis of electronegative low-density lipoprotein

Abstract

Low density lipoprotein is a heterogeneous group of lipoproteins that differs in lipid and protein composition. One copy of apolipoprotein (apo)B accounts for over 95% of the LDL protein, but the presence of minor proteins could disturb its biological behavior. Our aim was to study the content of minor proteins in LDL subfractions separated by anion exchange chromatography. Electropositive LDL [LDL(+)] is the native form, whereas electronegative LDL [LDL(−)] is a minor atherogenic fraction present in blood. LC-ESI MS/MS analysis of both LDL fractions identified up to 28 different proteins. Of these, 13 proteins, including apoB, were detected in all the analyzed samples. LDL(−) showed a higher content of most minor proteins. Statistical analysis of proteomic data indicated that the content of apoE, apoA-I, apoC-III, apoA-II, apoD, apoF, and apoJ was higher in LDL(−) than in LDL(+). Immunoturbidimetry, ELISA, or Western blot analysis confirmed these differences. ApoJ and apoF presented the highest difference between LDL(+) and LDL(−) (>15-fold). In summary, the increased content of several apolipoproteins, and specifically of apoF and apoJ, could be related to the physicochemical characteristics of LDL(−), such as apoB misfolding, aggregation, and abnormal lipid composition. Low density lipoprotein is a heterogeneous group of lipoproteins that differs in lipid and protein composition. One copy of apolipoprotein (apo)B accounts for over 95% of the LDL protein, but the presence of minor proteins could disturb its biological behavior. Our aim was to study the content of minor proteins in LDL subfractions separated by anion exchange chromatography. Electropositive LDL [LDL(+)] is the native form, whereas electronegative LDL [LDL(−)] is a minor atherogenic fraction present in blood. LC-ESI MS/MS analysis of both LDL fractions identified up to 28 different proteins. Of these, 13 proteins, including apoB, were detected in all the analyzed samples. LDL(−) showed a higher content of most minor proteins. Statistical analysis of proteomic data indicated that the content of apoE, apoA-I, apoC-III, apoA-II, apoD, apoF, and apoJ was higher in LDL(−) than in LDL(+). Immunoturbidimetry, ELISA, or Western blot analysis confirmed these differences. ApoJ and apoF presented the highest difference between LDL(+) and LDL(−) (>15-fold). In summary, the increased content of several apolipoproteins, and specifically of apoF and apoJ, could be related to the physicochemical characteristics of LDL(−), such as apoB misfolding, aggregation, and abnormal lipid composition. LDL, the main cholesterol carrier in plasma, is composed of approximately 75% lipid (mainly cholesterol) and 25% protein. The major protein in LDL is apolipoprotein B-100 (apoB-100), a protein of 550 kDa that accounts for more than 95% of the total protein mass in LDL (1Segrest J.P. Jones M.K. De Loof H. Dashti N. Structure of apolipoprotein B-100 in low density lipoproteins.J. Lipid Res. 2001; 42: 1346-1367Abstract Full Text Full Text PDF PubMed Google Scholar). However, minor amounts of other apolipoproteins associated to LDL have been reported. Several of these proteins, such as apoE, apoC-III, and platelet-activating factor acetylhydrolase (PAF-AH), have important roles in LDL metabolism and modulate its atherogenicity despite their low concentration (2Alaupovic P. Knight-Gibson C. Wang C.S. Downs D. Koren E. Brewer Jr., H.B. Gregg R.E. Isolation and characterization of an apoA-II-containing lipoprotein (LP-A-II:B complex) from plasma very low density lipoproteins of patients with Tangier disease and type V hyperlipoproteinemia.J. Lipid Res. 1991; 32: 9-19Abstract Full Text PDF PubMed Google Scholar, 3Fruchart J.C. Lipoprotein heterogeneity and its effect on apolipoprotein assays.Scand. J. Clin. Lab. Invest. Suppl. 1990; 198: 51-57Crossref PubMed Scopus (6) Google Scholar, 4Stafforini D.M. McIntyre T.M. Zimmerman G.A. Prescott S.M. Platelet-activating factor acetylhydrolases.J. Biol. Chem. 1997; 272: 17895-17898Abstract Full Text Full Text PDF PubMed Scopus (237) Google Scholar). Several studies have made a proteomic approach using 2D-electrophoresis or SELDI-based analysis to detect minor proteins in LDL (5Karlsson H. Leanderson P. Tagesson C. Lindahl M. Lipoproteomics I: mapping of proteins in low-density lipoprotein using two-dimensional gel electrophoresis and mass spectrometry.Proteomics. 2005; 5: 551-565Crossref PubMed Scopus (118) Google Scholar, 6Davidsson P. Hulthe J. Fagerberg B. Olsson B.M. Hallberg C. Dahllof B. Camejo G. A proteomic study of the apolipoproteins in LDL subclasses in patients with the metabolic syndrome and type 2 diabetes.J. Lipid Res. 2005; 46: 1999-2006Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar, 7Stahlman M. Davidsson P. Kanmert I. Rosengren B. Boren J. Fagerberg B. Camejo G. Proteomics and lipids of lipoproteins isolated at low salt concentrations in D2O/sucrose or in KBr.J. Lipid Res. 2008; 49: 481-490Abstract Full Text Full Text PDF PubMed Scopus (80) Google Scholar, 8Banfi C. Brioschi M. Barcella S. Wait R. Begum S. Galli S. Rizzi A. Tremoli E. Proteomic analysis of human low-density lipoprotein reveals the presence of prenylcysteine lyase, a hydrogen peroxide-generating enzyme.Proteomics. 2009; 9: 1344-1352Crossref PubMed Scopus (37) Google Scholar, 9Sun H.Y. Chen S.F. Lai M.D. Chang T.T. Chen T.L. Li P.Y. Shieh D.B. Young K.C. Comparative proteomic profiling of plasma very-low-density and low-density lipoproteins.Clin. Chim. Acta. 2010; 411: 336-344Crossref PubMed Scopus (54) Google Scholar), including apoE, apoC-III, apoC-II, apoA-I, apoA-IV, apoM, apoJ, serum amyloid A4 (SAA4), calgranulin A, lysozyme C, apoD, apoH, α1-antitrypsin, orosomucoid-1, paraoxonase-1, retinol binding protein, and prenylcysteine lyase-1. LDL is not a homogeneous entity but a group of particles that differs in density, size, electric charge, and composition. It is well established that small, dense LDL particles are more atherogenic than large, buoyant particles (10Krauss R.M. Dense low density lipoproteins and coronary artery disease.Am. J. Cardiol. 1995; 75: 53B-57BAbstract Full Text PDF PubMed Scopus (118) Google Scholar), and both of these subfractions differ in their protein content (6Davidsson P. Hulthe J. Fagerberg B. Olsson B.M. Hallberg C. Dahllof B. Camejo G. A proteomic study of the apolipoproteins in LDL subclasses in patients with the metabolic syndrome and type 2 diabetes.J. Lipid Res. 2005; 46: 1999-2006Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar). Another property of LDL that confers enhanced atherogenicity is increased electronegative charge. Electronegative LDL [LDL(−)] is a minor subfraction of plasma LDL that is pro-inflammatory and induces apoptosis in endothelial cells and leukocytes (11De Castellarnau C. Sanchez-Quesada J.L. Benitez S. Rosa R. Caveda L. Vila L. Ordonez-Llanos J. Electronegative LDL from normolipemic subjects induces IL-8 and monocyte chemotactic protein secretion by human endothelial cells.Arterioscler. Thromb. Vasc. Biol. 2000; 20: 2281-2287Crossref PubMed Google Scholar, 12Chen H.H. Hosken B.D. Huang M. Gaubatz J.W. Myers C.L. Macfarlane R.D. Pownall H.J. Yang C.Y. Electronegative LDLs from familial hypercholesterolemic patients are physicochemically heterogeneous but uniformly proapoptotic.J. Lipid Res. 2007; 48: 177-184Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar, 13Benitez S. Bancells C. Ordonez-Llanos J. Sanchez-Quesada J.L. Pro-inflammatory action of LDL(−) on mononuclear cells is counteracted by increased IL10 production.Biochim. Biophys. Acta. 2007; 1771: 613-622Crossref PubMed Scopus (33) Google Scholar). Its relative proportion is increased in subjects with a high cardiovascular risk (14Benitez S. Ordonez-Llanos J. Franco M. Marin C. Paz E. Lopez-Miranda J. Otal C. Perez-Jimenez F. Sanchez-Quesada J.L. Effect of simvastatin in familial hypercholesterolemia on the affinity of electronegative low-density lipoprotein subfractions to the low-density lipoprotein receptor.Am. J. Cardiol. 2004; 93: 414-420Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar, 15Sanchez-Quesada J.L. Perez A. Caixas A. Rigla M. Payes A. Benitez S. Ordonez-Llanos J. Effect of glycemic optimization on electronegative low-density lipoprotein in diabetes: relation to nonenzymatic glycosylation and oxidative modification.J. Clin. 2001; PubMed Scopus Google Scholar). LDL(−) an increased content of several minor proteins, such as apoE, apoC-III, and apoA-I, that could be in its (11De Castellarnau C. Sanchez-Quesada J.L. Benitez S. Rosa R. Caveda L. Vila L. Ordonez-Llanos J. Electronegative LDL from normolipemic subjects induces IL-8 and monocyte chemotactic protein secretion by human endothelial cells.Arterioscler. Thromb. Vasc. Biol. 2000; 20: 2281-2287Crossref PubMed Google Scholar, 12Chen H.H. Hosken B.D. Huang M. Gaubatz J.W. Myers C.L. Macfarlane R.D. Pownall H.J. Yang C.Y. Electronegative LDLs from familial hypercholesterolemic patients are physicochemically heterogeneous but uniformly proapoptotic.J. Lipid Res. 2007; 48: 177-184Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar, S. Sanchez-Quesada J.L. F. F. Ordonez-Llanos J. Platelet-activating factor acetylhydrolase is associated with electronegative low-density lipoprotein PubMed Scopus Google Scholar, J.L. M. R. Benitez S. Vila L. Ordonez-Llanos J. Electronegative LDL of characterization and of from human endothelial Full Text Full Text PDF PubMed Scopus Google Scholar, C.Y. Chen H.H. Huang J.L. Yang Chen Gaubatz J.W. Pownall H.J. low-density lipoprotein subfractions in type 2007; Full Text Full Text PDF PubMed Scopus Google Scholar, J.L. Benitez S. Otal C. Franco M. F. Ordonez-Llanos J. of electronegative LDL in normolipemic and Lipid Res. Full Text Full Text PDF PubMed Google Scholar). these proteins, as are present in very amounts in Our aim was to study in the content of minor proteins between native LDL [LDL(+)] and LDL using a gel on to mass were a from normolipemic cholesterol cholesterol subjects from the were in at and mass of all subjects was The study was by the and all their LDL was isolated from plasma in with an plasma from by The and of separated lipoproteins in human Clin. Invest. PubMed Scopus Google at and in presence of LDL(−) accounts for than of total LDL, the of plasma was the that to a of LDL(−) to proteomic the of plasma the analysis using to for LDL to LDL(−) protein of plasma was for and apoB of total LDL was LDL was LDL(+) and LDL(−) by as J.L. M. R. Benitez S. Vila L. Ordonez-Llanos J. Electronegative LDL of characterization and of from human endothelial Full Text Full Text PDF PubMed Scopus Google Scholar). LDL(−) proportion for and the was approximately a of apoB of of LDL subfractions was as (11De Castellarnau C. Sanchez-Quesada J.L. Benitez S. Rosa R. Caveda L. Vila L. Ordonez-Llanos J. Electronegative LDL from normolipemic subjects induces IL-8 and monocyte chemotactic protein secretion by human endothelial cells.Arterioscler. Thromb. Vasc. Biol. 2000; 20: 2281-2287Crossref PubMed Google Scholar, J.L. M. R. Benitez S. Vila L. Ordonez-Llanos J. Electronegative LDL of characterization and of from human endothelial Full Text Full Text PDF PubMed Scopus Google Scholar). including total and apoB were by in a LDL was by of LDL(+) with from at for 2 as A. M. induces and but aggregation, of low density lipoprotein to increased binding of LDL to human Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). The of (5Karlsson H. Leanderson P. Tagesson C. Lindahl M. Lipoproteomics I: mapping of proteins in low-density lipoprotein using two-dimensional gel electrophoresis and mass spectrometry.Proteomics. 2005; 5: 551-565Crossref PubMed Scopus (118) Google was with minor of LDL was by with of for 2 at and for at were with of and were at analysis than were by and using of The content of protein in the was by the The protein in of was to by with of a of in and for at of of a of in was and the was for at The protein was to The protein was in of in and of was at and the was by of and at Proteomic analysis was by LC-ESI MS/MS using of protein. using different were LC-ESI MS/MS analysis was on an mass to a were on a and a were by an in in a the of the mass MS/MS was on of the most as from a and using a of for optimization of MS/MS from was were identified using to the human MS/MS were with a mass of of with a of as and as The was as an for MS/MS higher than the The content of proteins in LDL subfraction was from the of MS/MS to protein detected by protein of to a content relative to the total proteins. were for all the analyzed of of the LDL the relative of the proteins between the the were to their total apoB content is of apoB LDL and by the protein of to a relative were as of protein for apoB apoA-II, apoE, apoC-III, and were in LDL subfractions using for as of was with of LDL at and at for of 2 was and at for was in a at the by the A was with an apolipoprotein from to ApoJ was by using of LDL at The content of apoJ and apoF in LDL subfractions was by Western LDL subfractions were to electrophoresis in was at V for 2 at were to a at in and and at with Western blot was using or as a or in was as a for apoJ or for apoF in was with The of to LDL subfractions was by native gel electrophoresis by Western was in as J.L. Benitez S. Otal C. Franco M. F. Ordonez-Llanos J. of electronegative LDL in normolipemic and Lipid Res. Full Text Full Text PDF PubMed Google Scholar). In lipoproteins were the gel as were to and Western blot was using a as a and as a was with protein was as the of from to LDL(+) or LDL(−) using lipoproteins isolated from of human normolipemic and as of J.C. J. A. Ordonez-Llanos J. F. F. in and Lipid Res. 2001; 42: Full Text Full Text PDF PubMed Google Scholar). of from to LDL were up to are as was between LDL subfractions were with for A was Lipid and protein of LDL fractions was to that (10Krauss R.M. Dense low density lipoproteins and coronary artery disease.Am. J. Cardiol. 1995; 75: 53B-57BAbstract Full Text PDF PubMed Scopus (118) Google Scholar, S. Sanchez-Quesada J.L. F. F. Ordonez-Llanos J. Platelet-activating factor acetylhydrolase is associated with electronegative low-density lipoprotein PubMed Scopus Google Scholar). LDL(−) higher and content and apoB content than LDL(+) The total protein content was very in LDL(+) and in was to the high of apoB, is and apoB of LDL LDL(+) using the LDL(+) using the LDL(+) using the LDL(+) using the in a were using LDL subfractions isolated from plasma from different A total of 28 proteins, including apoB, were detected in at of the The on protein including the different identified for protein, are in and in LDL(−) and proteins in proteins were in or in very low concentrations and of these proteins are in or proteins other than apoB were detected in or in or both samples. proteins were relative to apoB, and analysis indicated that the content of apoE, apoA-I, apoC-III, apoA-II, apoD, apoF, and apoJ was higher in LDL(−) than in LDL(+) was detected in LDL(−), whereas protein content was in LDL(+). were in apoC-II, and a to an increased content of all these proteins, with the of was in with of proteins detected in LDL of in a protein was amyloid protein factor and factor acetylhydrolase factor amyloid protein in a content of proteins detected by LC-ESI LDL(+) using the LDL(+) using the LDL(+) using the LDL(+) using the LDL(+) using the LDL(+) using the LDL(+) using the amyloid or were are in LDL(+) using the in a or were are in protein. The most proteins in a in both LDL fractions than of minor were in LDL(−) and in LDL(+) for more than of minor proteins. the of the is high in and in the analysis the of major between the LDL the increased content in LDL(−) of apolipoproteins detected by proteomic apoA-I, apoA-II, apoE, apoC-III, and were in LDL subfractions by to detect very low the content of these apolipoproteins in The between LDL(+) and LDL(−) was to that by proteomic analysis and the of and in both LDL subfractions with data (11De Castellarnau C. Sanchez-Quesada J.L. Benitez S. Rosa R. Caveda L. Vila L. Ordonez-Llanos J. Electronegative LDL from normolipemic subjects induces IL-8 and monocyte chemotactic protein secretion by human endothelial cells.Arterioscler. Thromb. Vasc. Biol. 2000; 20: 2281-2287Crossref PubMed Google Scholar, J.L. M. R. Benitez S. Vila L. Ordonez-Llanos J. Electronegative LDL of characterization and of from human endothelial Full Text Full Text PDF PubMed Scopus Google of apolipoproteins by or in LDL from LC-ESI LDL(+) using the LDL(+) using the LDL(+) using the LDL(+) using the apolipoproteins were by as in apoJ, was by are in LDL(+) using the in a apolipoproteins were by as in apoJ, was by are in Several of the apolipoproteins detected in LDL subfractions are of lipoproteins the of LDL subfractions could be with a Western blot was to detect apoA-I, the main protein of in LDL native a in was detected in the to LDL was more in LDL(−) than in LDL(+). was in the be ApoJ and apoF proteins presented the highest difference between LDL(+) and different Western to detect apoF and apoJ were in both LDL and Western of LDL(+) and LDL(−) and a higher content of apoF and apoJ in LDL(−) than in LDL(+). to apoF, an of kDa to apoF was detected in LDL(−), whereas was in LDL(+) to apoJ, a major of to the of apoJ, and minor of to and and were detected apoJ content by to from the proteomic analysis and confirmed the high content in The of apoF in LDL(−) is but could be the abnormal lipid of The of apoF was by the of as apoF is a of such lipid with LDL(−) a to from that a of plasma proteins to LDL in of these proteins and amounts were high were by in both LDL in a other proteins that were detected in or both LDL fractions were apoD, apoJ, apoF, and protein. the of the protein, the presence of all these proteins been in LDL D.M. McIntyre T.M. Zimmerman G.A. Prescott S.M. Platelet-activating factor acetylhydrolases.J. Biol. Chem. 1997; 272: 17895-17898Abstract Full Text Full Text PDF PubMed Scopus (237) Google Scholar, H. Leanderson P. Tagesson C. Lindahl M. Lipoproteomics I: mapping of proteins in low-density lipoprotein using two-dimensional gel electrophoresis and mass spectrometry.Proteomics. 2005; 5: 551-565Crossref PubMed Scopus (118) Google Scholar, 6Davidsson P. Hulthe J. Fagerberg B. Olsson B.M. Hallberg C. Dahllof B. Camejo G. A proteomic study of the apolipoproteins in LDL subclasses in patients with the metabolic syndrome and type 2 diabetes.J. Lipid Res. 2005; 46: 1999-2006Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar, 7Stahlman M. Davidsson P. Kanmert I. Rosengren B. Boren J. Fagerberg B. Camejo G. Proteomics and lipids of lipoproteins isolated at low salt concentrations in D2O/sucrose or in KBr.J. Lipid Res. 2008; 49: 481-490Abstract Full Text Full Text PDF PubMed Scopus (80) Google Scholar, 8Banfi C. Brioschi M. Barcella S. Wait R. Begum S. Galli S. Rizzi A. Tremoli E. Proteomic analysis of human low-density lipoprotein reveals the presence of prenylcysteine lyase, a hydrogen peroxide-generating enzyme.Proteomics. 2009; 9: 1344-1352Crossref PubMed Scopus (37) Google Scholar, 9Sun H.Y. Chen S.F. Lai M.D. Chang T.T. Chen T.L. Li P.Y. Shieh D.B. Young K.C. Comparative proteomic profiling of plasma very-low-density and low-density lipoproteins.Clin. Chim. Acta. 2010; 411: 336-344Crossref PubMed Scopus (54) Google Scholar). Several other proteins were detected in or in the of such as apoA-IV, and have been to be associated with lipoproteins J.C. Lipoprotein heterogeneity and its effect on apolipoprotein assays.Scand. J. Clin. Lab. Invest. Suppl. 1990; 198: 51-57Crossref PubMed Scopus (6) Google Scholar, 4Stafforini D.M. McIntyre T.M. Zimmerman G.A. Prescott S.M. Platelet-activating factor acetylhydrolases.J. Biol. Chem. 1997; 272: 17895-17898Abstract Full Text Full Text PDF PubMed Scopus (237) Google Scholar, H. Leanderson P. Tagesson C. Lindahl M. Lipoproteomics I: mapping of proteins in low-density lipoprotein using two-dimensional gel electrophoresis and mass spectrometry.Proteomics. 2005; 5: 551-565Crossref PubMed Scopus (118) Google Scholar, 6Davidsson P. Hulthe J. Fagerberg B. Olsson B.M. Hallberg C. Dahllof B. Camejo G. A proteomic study of the apolipoproteins in LDL subclasses in patients with the metabolic syndrome and type 2 diabetes.J. Lipid Res. 2005; 46: 1999-2006Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar, 7Stahlman M. Davidsson P. Kanmert I. Rosengren B. Boren J. Fagerberg B. Camejo G. Proteomics and lipids of lipoproteins isolated at low salt concentrations in D2O/sucrose or in KBr.J. Lipid Res. 2008; 49: 481-490Abstract Full Text Full Text PDF PubMed Scopus (80) Google Scholar, 8Banfi C. Brioschi M. Barcella S. Wait R. Begum S. Galli S. Rizzi A. Tremoli E. Proteomic analysis of human low-density lipoprotein reveals the presence of prenylcysteine lyase, a hydrogen peroxide-generating enzyme.Proteomics. 2009; 9: 1344-1352Crossref PubMed Scopus (37) Google Scholar, 9Sun H.Y. Chen S.F. Lai M.D. Chang T.T. Chen T.L. Li P.Y. Shieh D.B. Young K.C. Comparative proteomic profiling of plasma very-low-density and low-density lipoproteins.Clin. Chim. Acta. 2010; 411: 336-344Crossref PubMed Scopus (54) Google Scholar, P. as the for plasma of and lipoprotein Lipid Res. 1991; PubMed Scopus Google Scholar). are to be in and It been that proteins and to lipoproteins A. C.Y. J.W. the and or of cardiovascular Lipid Res. 2005; 46: Full Text Full Text PDF PubMed Scopus Google Scholar). It is to the of these proteins in LDL but is The is as LDL is its main in plasma D.M. McIntyre T.M. Zimmerman G.A. Prescott S.M. Platelet-activating factor acetylhydrolases.J. Biol. Chem. 1997; 272: 17895-17898Abstract Full Text Full Text PDF PubMed Scopus (237) Google and protein a major in the by LDL S. Sanchez-Quesada J.L. F. F. Ordonez-Llanos J. Platelet-activating factor acetylhydrolase is associated with electronegative low-density lipoprotein PubMed Scopus Google Scholar). of the proteomic studies detected in LDL, of plasma is to LDL to LDL(−) D.M. McIntyre T.M. Zimmerman G.A. Prescott S.M. Platelet-activating factor acetylhydrolases.J. Biol. Chem. 1997; 272: 17895-17898Abstract Full Text Full Text PDF PubMed Scopus (237) Google Scholar). The high affinity binding between and apoB C. C. G. Zimmerman G.A. McIntyre T.M. D.M. Prescott S.M. and of plasma platelet-activating factor Biol. PubMed Google could was detected in in the present study and in studies using a proteomic It is that most was to its to the The presence of proteins is to in the proteomic in the protein content in the and studies be to in the and could in the of proteins from LDL to high and The of apolipoproteins and with lipoproteins their and most of these proteins to a protein is detected in all analyzed be that for a of of LDL particles and could have a in their metabolic in blood. data that LDL(−) a higher content of minor proteins than LDL(+). The content of most of the analyzed proteins was higher in LDL(−), were in proteins. In to the higher content of apoE, apoC-III, and in LDL(−) (11De Castellarnau C. Sanchez-Quesada J.L. Benitez S. Rosa R. Caveda L. Vila L. Ordonez-Llanos J. Electronegative LDL from normolipemic subjects induces IL-8 and monocyte chemotactic protein secretion by human endothelial cells.Arterioscler. Thromb. Vasc. Biol. 2000; 20: 2281-2287Crossref PubMed Google Scholar, 12Chen H.H. Hosken B.D. Huang M. Gaubatz J.W. Myers C.L. Macfarlane R.D. Pownall H.J. Yang C.Y. Electronegative LDLs from familial hypercholesterolemic patients are physicochemically heterogeneous but uniformly proapoptotic.J. Lipid Res. 2007; 48: 177-184Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar, J.L. M. R. Benitez S. Vila L. Ordonez-Llanos J. Electronegative LDL of characterization and of from human endothelial Full Text Full Text PDF PubMed Scopus Google Scholar, I. B. B. N. A electronegative LDL subfraction is present in human Thromb. Vasc. Biol. PubMed Scopus Google Scholar), that apoD, apoJ, apoF, and were increased in of these proteins apoA-II, apoD, and are to The presence in LDL of proteins to been J.C. Lipoprotein heterogeneity and its effect on apolipoprotein assays.Scand. J. Clin. Lab. Invest. Suppl. 1990; 198: 51-57Crossref PubMed Scopus (6) Google Scholar, P. as the for plasma of and lipoprotein Lipid Res. 1991; PubMed Scopus Google Scholar), and could be that the presence of these proteins in LDL is to the presence of However, the of is very low the density in the present study to LDL to the of Western blot analysis to detect native that was specifically to The increased content of is to with LDL the density of LDL and LDL was isolated in the density in the present minor was detected in total by in all LDL was than is in with of proteomic a very high content of confers enhanced to the of in total LDL to its with However, the content of in LDL(−) was than In apoJ and apoF could a in the of LDL(−), as both proteins were detected in higher concentrations in LDL(−) than in LDL(+). The biological characteristics of these proteins could of as been in and and However, in these are not well as apoJ including apoptosis H. R. Wang C.Y. apoptosis by with Biol. 2005; PubMed Scopus Google and of the T.L. of plasma proteins and on PubMed Scopus Google Scholar). been that apoJ the oxidative of LDL M. S. G. E. apoJ in and and in apolipoprotein Thromb. Vasc. Biol. 2005; PubMed Scopus Google Scholar). The of apoJ with LDL(−), but not could be by its ApoJ is the identified and to a of proteins that present S. that and binding PubMed Scopus Google Scholar), including M. A. B. J. and 2005; PubMed Scopus Google Scholar). The binding of apoJ to proteins its by protein 2 and its and S. that and binding PubMed Scopus Google Scholar). LDL(−) including C. Benitez S. S. Ordonez-Llanos J. Sanchez-Quesada J.L. associated with electronegative low-density lipoprotein are in increased 2008; PubMed Scopus (37) Google and apoB G. R. G. G. A. F. of and in electronegative Biol. 2001; PubMed Scopus Google Scholar, De M. G. R. G. L. G. E. M. G. density lipoprotein and J. 2008; PubMed Scopus Google Scholar), that could be related to the presence of apoJ in In with apoJ, apoF lipid a as a of D.M. R.E. and of lipid protein reveals its with apolipoprotein Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). is associated with LDL, and its action is to the of the between and LDL R.E. of lipid between lipoproteins by an plasma lipoprotein Lipid Res. Full Text PDF PubMed Google Scholar). the of and between LDL to and from In LDL from and to The that most apoF is to LDL(−) that lipid exchange between LDL subfraction and other lipoproteins could be Our data that lipid exchange between and LDL(−) is low to the high content of the of in plasma is R.E. of lipid between lipoproteins by an plasma lipoprotein Lipid Res. Full Text PDF PubMed Google Scholar), could be with the increased relative content of in the increased content of apoC-III, the of lipoprotein in with apoC-II, the of could be related with increased content of In summary, a of proteins that are associated with LDL of have not been identified LDL(−) a higher content of most of these proteins than LDL(+). The increased content of of these proteins, such as apoC-III, apoE, and apoA-I, been in LDL(−), but in apoA-II, apoD, apoJ, and apoF in LDL(−) are for the and apoJ, content in LDL(−) is higher than in are of as could be in of the atherogenic of However, studies are to the roles that apoF and apoJ could in the abnormal characteristics of The for with apolipoprotein protein gel electrophoresis low-density lipoprotein electronegative low-density lipoprotein lipoprotein low-density lipoprotein protein 2 platelet-activating serum amyloid A4