Review Article Mass Spectrometry-Based Proteomic …downloads.hindawi.com/journals/bmri/2015/164846.pdfReview Article Mass Spectrometry-Based Proteomic Study Makes High-Density Lipoprotein

Review ArticleMass Spectrometry-Based Proteomic StudyMakes High-Density Lipoprotein a Biomarker forAtherosclerotic Vascular Disease

Chiz-Tzung Chang123 Chao-Yuh Yang34 Fuu-Jen Tsai5

Shih-Yi Lin12 and Chao-Jung Chen67

1College of Medicine China Medical University 91 Hsueh-Shih Road Taichung 40402 Taiwan2Division of Nephrology China Medical University Hospital 2 Yu-Der Road Taichung 40447 Taiwan3L5 Research Center China Medical University Hospital Taichung Taiwan4Section of Cardiovascular Research Department of Medicine Baylor College of MedicineOne Baylor Plaza Houston TX 77030 USA5Department of Medical Genetics Pediatrics and Medical Research China Medical University Hospital Taichung 40447 Taiwan6Proteomics Core Laboratory Department of Medical Research China Medical University Hospital Taichung 40447 Taiwan7Graduate Institute of Integrated Medicine China Medical University Taichung 40402 Taiwan

Correspondence should be addressed to Chao-Jung Chen cjchenmailcmuedutw

Received 28 July 2014 Revised 1 December 2014 Accepted 12 February 2015

Academic Editor Shi-Jian Ding

Copyright copy 2015 Chiz-Tzung Chang et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

High-density lipoprotein (HDL) is a lipid and protein complex that consists of apolipoproteins and lower level HDL-associatedenzymesHDLdysfunction is a factor in atherosclerosis and decreases patient survivalMass spectrometry- (MS-) based proteomicsprovides a high throughput approach for analyzing the composition and modifications of complex HDL proteins in diseasesHDL can be separated according to size surface charge electronegativity or apoprotein composition MS-based proteomics onsubfractionated HDL then allows investigation of lipoprotein roles in diseases Herein we review recent developments in MS-based quantitative proteomic techniques HDL proteomics and lipoprotein modifications in diseases and HDL subfractionationstudies We also discuss future directions and perspectives in MS-based proteomics on HDL

1 Introduction

High-density lipoprotein (HDL) is a heterogeneous complexof differing size density surface charge and lipoproteincontent [1] SerumHDL level is thought to be inversely relatedwith atherosclerotic vascular disease (ASVD) risk [2 3] HDLcan protect against atherosclerosis via its cholesterol acceptorand effects in antioxidation anti-inflammation and anti-apoptosis [4ndash6] However several clinical studies using ther-apeutic serum HDL-elevating agents failed to demonstratetheir clinical benefits [7] Recent studies have shown thatHDL protein oxidation glycation carbamylation and othermodifications can compromise HDL function and result inincreased ASVD risk [8ndash10] Thus protein composition

changes or modifications on HDL can act as biomarkersfor ASVD With the improvement in subfractionation ofHDL complexes and the advance in MS-based proteomicapproaches it is feasible to analyze HDL proteome and theirmodifications giving a global viewof biological processes andmolecular functions of HDL proteins in diseases

2 HDL Composition andProtein Heterogeneity

HDL (density = 1063ndash1210 gmL) [11] is composed ofapproximately equal mass portions of proteins and lipidswhose molar differences result in HDL heterogeneity [12]

Hindawi Publishing CorporationBioMed Research InternationalVolume 2015 Article ID 164846 13 pageshttpdxdoiorg1011552015164846

2 BioMed Research International

ApoA1ad

Albuminf

ApoA2ad

ApoBa

Alpha1-antitrypsinb

ApoA4a

ApoEad

Apo (a)ae

SAA4b

ApoC3a

ApoDa

Complement C3c

Transthyretinb

LCATad

PON-1d

ApoMa

ApoC1a

ApoJa

ApoC2a

ApoFa

PLTPa

IgG1 C-chainc

PON-3d

Haptoglobinf

SAA1b

ApoC4a

Antithrombin IIIe

AMBPf

Gelsolinb

ApoA5a

0 200 400 600 800 1000

Identified peptide spectra

Figure 1 HDL proteome analysis by nano-LC-MSMSThe identified peptide spectra ofmajor proteins were presented as horizontal bars andtheir main functions were categorized a lipid transport protein b acute phase protein c complement and immunological pathway proteind antioxidant protein e hemostasis-associated protein f other cellular processes

Indeed HDL particles carry more than 80 different types ofproteins and 100 types of lipid species [13 14] In terms ofstructure typically HDL is broadly spherical (diameter 70ndash100 A) but nascent HDL is discoidal [15]

Nanoflow liquid chromatography (nano-LC) coupledonline with nanoelectrospray ionization-tandem MS (nano-ESI-MSMS) has become the gold standard for high through-put identification of proteins in complex biological samplesFigure 1 showed the major identified proteins on HDL bynano-LC-MSMS These proteins can be categorized intolipid transporter proteins complement pathway proteinsimmunological pathway proteins acute phase proteins andantioxidant and hemostasis-associated proteins (Figure 1)HDL proteome diversity was compatible with multifunc-tional roles of HDL on lipid metabolism oxidation immunereaction inflammation and hemostasis Apolipoprotein A1(ApoA1) and ApoA2 take up 70 and 20 of HDL proteinmass respectively [16] but ApoA4 ApoE ApoC ApoJ andothers are also present in less amounts ApoE is polymorphicand has three major isoformsmdashApoE2 ApoE3 and ApoE4[17] ApoC is a family with four members ApoC1 ApoC2ApoC3 and ApoC4 each with several isoforms [18 19] HDLalso contains small amounts of miscellaneous proteins forexample acute-phase protein HDL-associated enzymes forexample paraoxonase-1 (PON-1) lecithin-cholesterol acyl-transferase (LCAT) and lipoprotein-associated phospholi-pase A2 (Lp-PLA2) HDL lipids comprise a phosphatidyl-choline bilayer and a cholesteryl ester core including a small

amount of cholesterol and triglyceride [20] The cholesterylester and triglyceride content of HDL can affect HDL sizeparticles with higher triglyceride content tend to be larger[21] Cholesteryl ester transfer proteins (CETP) mediatethe transfer of cholesteryl esters from HDL to low-densitylipoproteins (LDL) or very low-density lipoproteins (VLDL)in exchange for triglycerides Similarly phospholipid trans-fer proteins (PLTP) transfer phospholipids between HDLand VLDL These two transfer proteins and other plasmaenzymes such as hepatic lipase and secretory phospholipaseA2 play important roles in HDL composition regulation[2] ApoC family members also play an important role inthe metabolism and compositions of HDL ApoC1 inhibitsCETP ApoC2 activates lipoprotein lipase ApoC3 inhibitslipoprotein lipase [19 22 23] Whilst ApoC4 has a lowerplasma concentration than Apo C1 C2 or C3 it existsprimarily in VLDL and HDL and plays a role in lipoproteinmetabolism

HDL composition can also be affected by inflammation[24] or disease such as uremia [25] psoriasis [26] or diabetes[27] Patients with low HDL-cholesterol (HDL-C) expressedhigher serum levels of C-reactive proteins [28] In addition toproteins and lipids HDL in both healthy and sick individualsalso contains small amounts of microRNAs [29] In factmicroRNAs have been shown to govern HDL metabolismand reverse cholesterol transport (RCT) the export of choles-terol frommacrophages and peripheral tissues to the liver forbiliary excretion [30]

BioMed Research International 3

3 HDL Functions and Associated Diseases

In the vascular wall macrophages and resident cells engulfoxidized and other modified LDLs leading to atherosclerosis[31] Vasoprotective and antiatherogenic HDL can reverse theatherosclerotic process The antiatherogenic function comesmainly from RCT [5] ATP-binding cassette transportersABCA1 and ABCG1 transfer cholesterol in macrophage foamcells to lipid-free ApoA1 and ApoE [32] or frommacrophagesto HDL particles [33] respectively The ABCA1-ApoA1 axisplays a major role in cholesterol efflux [34] therefore RCTcan predict atherosclerosis in humans [4] Recently RCThas also been reported to affect the macrophage immuneresponse [35] nitric oxide (NO) production by endothelialnitric oxide synthase (eNOS) and insulin secretion frompancreatic islet cells [34 36] Through enhancement ofendothelial NO formation and vasodilation HDL inhibitsendothelial cell apoptosis and stimulates endothelial cellrepair and vasoprotection [37 38] However some believethat HDL vasoprotection may be independent of the NOpathway [39 40] HDL also has antioxidant antiplateletand anti-inflammatory effects which are all individuallyantiatherogenic and vasoprotective in nature AdditionallyHDL metabolizes triglyceride-rich lipoprotein by donatingApoE or ApoC to nascent chylomicron or VLDL [31]

ApoA1 and HDL-associated enzymes play key roles inRCT antiendothelial cell apoptosis [41] antioxidation andanti-inflammation [9] In an esterase with peroxidase-likeactivity [42] PON-1 associates with ApoA1 and exerts itsatheroprotective effect by preventing LDL from oxidativemodifying [43 44] Lp-PLA2 is not only a novel risk factorfor atherosclerosis [45 46] but also an antioxidant due toits role in reducing oxidized lipids [47] LCAT plays animportant role in RCT by esterifying cholesterol to facilitateHDLmaturation and subsequent cholesterol excretion in theliver [5]

Low plasma HDL-C has long been known as a significantindependent risk factor of atherosclerosis in patients withcoronary artery disease (CAD) diabetes [48 49] and uremia[20] it persists even after adjustment for obesity and hyper-triglyceridemia [50] Meta-analysis from large prospectivestudies demonstrated a 2-3 decrease in CAD risk for every1mgdL increase in HDL-C plasma levels [51] Furthermorethe Framingham study revealed a significant CAD riskincrease in patients with plasma HDL-C of lower than34mgdL [3] However established medications targeted atelevating HDL-C such as statin nicotinic acid or fibrate failto reduce atherosclerosis risk [52] Novel agents such as CETPinhibitors focused on raising HDL-C although promisinglack verification of their efficacy from large long-termrandomized control trials [53] Many other small moleculesor peptides are still undergoing different stages of basic orclinical studies and have not yet been put into clinical use[54]

Recent studies have indicated that biochemical alterationsor changes in the protein content of HDL may lead toHDL dysfunction in patients with CAD ischemic strokeAlzheimerrsquos disease or uremia [55 56] For example patientswith high atherosclerotic vascular disease risks such as

smokers exhibit lower HDL PON-1 mass and activity thanthose with low risks such as nonsmokers [57] moreoveruremia patients have lower LCAT levels and activities thanpatients without uremia [58]

4 MS-Based QuantitativeProteomic Approaches

To compare protein expression between different biologicalsamples quantitative proteomics has developed both gel-based and gel-free methods In two-dimensional polyacry-lamide gel electrophoresis (2D-PAGE) thousands of proteinsare separated in a gel matrix based on isoelectric point (firstdimension) and molecular weight (second dimension) Theintroduction of fluorescent Cy dyes (Cy2 Cy3 and Cy5) in2D-PAGE greatly improved protein quantitation precision[59]

Gel-free quantitative proteomics divides into label-freeand label-based methods In label-free quantitative pro-teomics spectral counting of a protein or ion intensity ofeach peptide can be used to calculate the relative proteinexpression level The spectral count strategy is based onthe positive correlation of protein abundance with sequencecoverage and the number of identified MSMS spectra [60]Although spectral counting is efficient cost effective andeasy to perform the precision and the analysis of complexprotein mixtures are questionable The ion peak intensitymethod which is based on the linear correlation betweenion peak intensity and peptide concentration within thedynamic range of a mass analyzer [61] is a more reliablestrategy however this method requires a package of reliablestatistical software One of the label-free approaches basedon comparing peak intensity extracted from nano-LC-MSscan with t-test is shown in Figure 2 Each sample groupof digested proteins has to be performed with replicatednano-LC-MS runs for quantitation of peptide ions and nano-LC-MSMS runs for acquiring MSMS spectra for proteinidentification

Labeling methods include isotope coded protein labeling(ICPL) isobaric tags for relative and absolute quantifica-tion (iTRAQ) tandem mass tag (TMT) and stable isotopelabeling with amino acids in cell culture (SILAC) amongothers iTRAQ is currently the most popular and widelyutilized labeling method in quantitative proteomics andutilizes an isobaric tag (total mass of 145Da) consisting of areporter group (mass = 114ndash117Da) a balance group (mass =31ndash28Da) and a peptide reactive group Upon peptidefragmentation measurement of the reporter ion intensities(eg 114ndash117Da of 4-plex iTRAQ kit) enables the relativequantitation of proteins in each sample [62] To increase thenumbers of identified proteins strong cation exchange (SCX)chromatography is usually used to subfractionate iTRAQ-labeled peptides The general analytical flow chart of labelingpeptides with iTRAQ followed by SCX fractionation andnano-LC-MSMS analysis is shown in Figure 3 HoweveriTRAQquantitation precisionmay be interfered by themixedMSMS contribution occurring during precursor selectionwhen analyzing highly complex mixtures [63]

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LC-MS replicated survey

Sample preparation and collection

Online nano-LC-MS analysis of peptides

Proteindigests 1

Proteindigests 2

Proteindigests 3

Proteindigests 4

Inte

nsity

Inte

nsity

Inte

nsity

Inte

nsity

Inte

nsity

Inte

nsity

Inte

nsity

Inte

nsity

Inte

nsity

Inte

nsity

Inte

nsity

Inte

nsity

Peak IDIntensity

001

004003002

1640

5408901000

1100164016001880

1900500840500

Data exportTime alignmentIntensity statistics

Multivariate analysis

Protein expressedin different ratios

Sample 1 Sample 2 Sample 3

Sample 1 Sample 2 Sample 3

Sample 4

Sample 1Sample 2Sample 3Sample 4

Sample 4Sample 3

Sample 2Sample 1

Fold

s cha

nge

Peptide qualitative identification andprotein library search

Quantitative Qualitative

analysis of peptides

Integration of quantitativeand qualitative protein

information byProteinScape software

Qua

ntita

tive a

naly

sis b

y M

S sp

ectr

a

Qua

litat

ive a

naly

sis b

y M

SM

S sp

ectr

a

mz mz mz mz

mz mz mz mz

mz mz mz mz

middot middot middot

middot middot middot

t-test

t-test calculationby ProfileAnalysis softwareSample 1 versus sample 2Sample 2 versus sample 3Sample 3 versus sample 4

Protein 4Protein 1 Protein 2 Protein 3

Online nano-LC-MSMS

Figure 2The flow chart of label-free quantitative proteomics based on extracted ion chromatographyThe label-free quantitative proteomicswas achieved by the software packages of DataAnalysis ProfileAnalysis and ProteinScape from Bruker Daltonics Each sample group ofdigested proteins was tested by nano-LC-MSwith replicated runs for quantitation of peptide ionsMSMS spectra were also acquired by nano-LC-MSMS analysis of these digested samples for protein identification The intensity and elution time of each peptide ions were recordedas a quantitative ldquomolecular featurerdquoThese molecular feature ions acquired from different nano-LC-MS runs were aligned according to theiraccurate masses and reproducible LC retention time Peptide peaks with expression ratios between two sample groups were calculated witht-test method in ProfileAnalysis These t-test results were further transferred to ProteinScape and combined with their protein identificationresults for integrating both quantitative and qualitative information of each protein in all sample groups

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iTRAQreagent

114

iTRAQreagent

115

iTRAQreagent

116

iTRAQreagent

117

Reduction

Alkylation

Tryptic digestion

Mixed

NH

31 114iTRAQlabeled

NH

30 115NH

29 116 NH

28 117

Target peptide

Retention time

TIC

Inte

nsity

Quantitation tags

Choose precursorsfor MSMS

Bioinformatic tools

Qualitative informationpeptide fragments

Protein identificationProtein quantitation

Ratio

s

115114 116 117

MS inlet

Nano-LC seperation Spray tip

ZDV union

LC-ESI-MSMS

SCX fractionation

Sample 1 Sample 2 Sample 3 Sample 4

Sam

ple 1

Sam

ple 2 Sam

ple 3

Sam

ple 4

mz middot middot middotProtein 1 Protein 2 Protein 3

Figure 3 General flow chart of 4-plex iTRAQ labeling with SCX fractionation and nano-LC-MSMS analysis Proteins of each sample groupwere reduced and alkylated followed by enzymatic digestion Four-plex iTRAQ reagents were used to label 4 protein digested samples Thecombined mass of the reporter (114 115 116 and 117Da) and the balance groups of labeling tag is 145Da After labeling the 4 iTRAQ-labeledsamples were mixed to become one sample followed by desalting purification SCX fractionation is an optional method to reduce complexityof peptide mixtures prior to nano-LC-MSMS analysisTheMSMS spectra were searched against protein database for protein identificationBioinformatics tools are used to integrate the protein identification and quantitation information with mass tags of 114 115 116 and 117Da intheir corresponding peptide MSMS spectra

Unlike other chemically labeled methods SILAC ismetabolically labeled in cell culture with heavy forms ofamino acids Because SILAC-labeled samples can be mixedimmediately before any further processing steps this min-imizes quantitative errors due to sample handling SILAC

has been widely applied in mammalian cell culture andsimple microorganisms and successfully extended to fruitflies and mice by feeding them lysine-labeled yeast anddiet respectively [64 65] Several SILAC-labeled cell linescan also be mixed together (super-SILAC) and serve as

6 BioMed Research International

SAA

4

ApoA

1

ApoC

1

proC

II

66312

94215

280775

140379

172481128627

000

025

050

075

100

125

150

5 75 10 125 15 175 20 225 25 275

ApoA

12+

ApoA

II998400

ApoC

III 1

ApoC

1998400

ApoA

IIm

onom

erAp

oCII

I 0

times104

times103

Inte

nsity

mz

Figure 4 MALDI-TOF-MS analysis of human HDL HDL was dia-lyzed against degassed 20mM Tris-HCl 05mM EDTA and 002NaN3 pH 80 at 4∘C with 3 buffer changes in 24 hours MALDI-

TOF-MS (Ultraflex III TOFTOF Bruker Daltonics Germany) withlinear mode was used to identify the major apolipoproteins andtheir isoforms in HDL Other detailed experimental settings can bereferred to in [16] ApoC1 (calculated mass 66306 mz) ApoC11015840ApoC1 minus N-terminus Thr-Pro (calculated mass 64324 mz)ApoCIII

0(calculated mass 87657 mz) ApoAII monomer single

chain ApoAII (calculated mass 88099 mz) proCII (calculatedmass 89149 mz) SAA4 (calculated mass 128632 mz) ApoAII1015840apoAII minus C-terminus-Gln (calculated mass 172537 mz)ApoAI (calculated mass 28078mz)

the spike-in standard SILAC for human tissue proteomestudy [66] However SILAC is hardly ever applied in HDLproteomics

Although 2D-PAGE analysis is laborious 2D-PAGE hasbeen applied for observing oxidative damage of ApoA1 [67]and glycation [68] with high protein separation efficiencyUnlike labeling approaches label-free approaches are stilllimited to their quantitative accuracy in the integrated data oftwo-dimensional separated subfractions Due to the limitedprotein numbers on HDL it is feasible to detect completeproteins on HDL in a single nano-LC-MSMS run Howeveronce considering 4 or more sample groups for comparisonlabeling methods were recommended as more time savingapproaches

In addition to nano-LC-MSMS-based quantitative pro-teomicsmethodsmatrix-assisted laser desorptionionization(MALDI) has also been used as a relatively quantitative toolto rapidly discover biomarkers in bacteria [56] serum ureaand salivaWith the use of stationary phases-coatedmagneticparticles or sample plates (eg surface-enhanced laser des-orptionionization (SELDI) [69]) for specific biomolecularpurification MALDI-time of flight (TOF) can be used torapidly detect specific compounds

However MALDI-TOF-based protein profiling is stillconstrained by poor sensitivity in detection of larger pro-teins (gt30 kDa) and limited ion peaks in complex samplesFortunately because major lipoproteins on HDL are smallerthan 30 kDa MALDI-TOF is quite suitable for revealingexpression changes of major HDL lipoproteins and theirisoforms in different disease backgrounds (Figure 4) Morecomprehensive protein profiling can be observed after HDLsubfractionation [16]

5 HDL Fractionation Techniques

The heterogeneity of HDL stems from its variation in densitysize composition and surface charge [1] Fractionating HDLinto subgroups may facilitate the compositional and func-tional studies of HDL In MS analysis sample fractionationcan reduce sample complexity therefore decreasing ionsuppression effects of ESI and MALDI to improve detectionsensitivity Most commonly HDL is separated into subclassesusing density gradient ultracentrifugation which can be usedto separate HDL2 (119889 = 1063ndash1125 gmL) and HDL3 (119889 =1125ndash1210 gmL) [70] Another frequently used method issubfractionation by size which is accomplished by nonde-naturing gradient gel electrophoresis or nuclear magneticresonance (NMR) spectroscopy [71] In order of decreasingsize HDL can be separated into HDL2b HDL2a HDL3aHDL3b andHDL3c [72]HDL can also be separated based onsurface charge into pre-beta alpha and pre-alpha HDL usingagarose gel electrophoresis [73] Some studies have classifiedHDL according to ApoA1ApoA2 composition into LipA1LipA1A2 and LipA2 [74] The above methods are limitedin that they may lose of some material during ultracentrifu-gation lack standardized methods for gel electrophoresisand include unknown assumptions in the NMR data analysissoftware [75]

Recently we successfully fractionated HDL from normaladults according to electronegativity HDL can be separatedinto five subfractions (H1ndashH5) with increasing electronega-tivity using a fast protein LC anion-exchange column [16]When subjected to SDS gel electrophoresis apolipoproteindistributions in H1 to H5 differed ApoC1 which carries astrong positive charge at physiological plasma pH is locatedmainly in H1 On the other hand ApoC3 which carriesseveral negatively charged sialic acid residues is found inH5 The amounts of ApoA1 decreased from H1 to H5 Thesame lipoprotein protein distribution in HDL subfractionswas determined by MALDI-TOF-MS

The distributions of major HDL-associated enzymessuch as PON-1 Lp-PLA2 and LCAT also differ amongthese 5 subfractions LCAT levels are higher in H4 and H5than in H1ndashH3 and LCAT activity is in agreement withthis distribution The RCT function of HDL subfractionshowever is lowest in H5 due to its lowest ApoA1 content Itis apparent that subgrouping HDLs according to electroneg-ativity can separate apolipoproteins with good resolutionfor HDL composition determination and functional studiesThis novel HDL subgrouping method provides an additionalscope to study HDL compositional changes and biofunctionsin various diseases such as diabetes hyperlipidemia anduremia

6 HDL Proteomics in Disease

HDL proteomics have been extensively reviewed [13 76 77]therefore in this review we focus on recently publishedpapers (Table 1) The proteome can also be altered afterdisease treatment Jorge et al reported that HDL proteomein CAD patients changed dynamically according to disease

BioMed Research International 7

Table 1 Selected studies of MS-based HDL proteomics

Disease Study population Quantitative strategy MSapproach Validation Major findings

CAD withPTCA [78] CAD (119899 = 21)

16O18O and iTRAQlabeling IEF andSCX seperation

Nano-LC-MSMS None Protective properties of HDL might be

impaired after PTCA

ACS [98] ACS (119899 = 40)healthy (119899 = 40) 2D-DIGE MALDI-

TOF-TOFELISA

Western blot

Functional HDL subfractions shifted todysfunctional HDL subfractions during

ACS

CAD [99]CAD (119899 = 6)

ACS (119899 = 6) andhealthy (119899 = 6)

1D-PAGE andlabel-free

quantification(peptide index)

Nano-LC-MSMS

ELISAIHC

Western blot

A reduced clusterin and increasedapolipoprotein C-III content of HDL inCAD and ACS as mechanisms leading toaltered effects on endothelial apoptosis

Hemodialysis(HD) [79]

HD (119899 = 30)healthy (119899 = 30)

iTRAQ with IEFfractionation

LC-MALDI-TOF ELISA

Increase of apoCIIapoCIII and thedecrease of serotransferrin in HDL of HD

patients

CADACS [80]

Healthy (119899 = 10)CAD (119899 = 10)

and ACS (119899 = 10)

Label-freequantification

(spectral counts andemPAI)

Nano-LC-MSMS

Immunoblotor ELISA

Increased abundance of SAA C3 andother inflammatory proteins in HDL fromACS patients suggests that HDL reflects a

shift to an inflammatory profile

AMI [82]AMI (119899 = 39)

FH (119899 = 100) andhealthy (119899 = 60)

2D-PAGE MALDI-TOF

ELISAWestern blot

TTR values are reduced in patients withhigh cardiovascular risk

Uremia [81]

ESRD (119899 = 24)healthy (119899 = 22)

and CKD(119899 = 22)

1D-PAGE label-freemethod withpeptide index

Nano-LC-MSMS

ELISAWestern blot

SAA in ESRD-HDL can promoteinflammatory cytokine production

CAD [8] CAD (119899 = 18)healthy (119899 = 20)

MALDI-TOFpeptide profiling

MALDI-TOF-TOF MALDI-TOF

Developed a MALDI-TOF patterncontaining peptides from apoA-I(oxidation at Met (112)) apoC-III(upregulated) lipoprotein(a)(upregulated) and apoC-I

(downregulated) to classify CAD andcontrol subjects

PTCA percutaneous transluminal coronary angioplasty ACS acute coronary syndromes AMI acute myocardial infarction CVD cardiovascular diseaseCAD coronary artery disease EBI European Bioinformatic Institute FH familiar hypercholesterolemia MI myocardial infarction MS mass spectrometerUC ultracentrifugation RA rheumatoid arthritis HD hemodialysis

status HDL proteins altered after percutaneous translumi-nal coronary angioplasty (PTCA) Several apolipoproteinsand fibrinogen-like protein increased but antithrombin IIIannexin A1 and several immunoglobulins decreased afterPTCA-induced atheroma plague rupture Protective proper-ties of HDL were impaired after PTCA [78]

Vaisar et al used a label-free quantitative proteomicmethod (peptide index) to study differential protein expres-sion in HDL3 of CAD patients and identified 48 differentproteins in HDL and HDL3 fractions which were cate-gorized as lipid metabolism proteinase inhibition acute-phase response and complement regulation by gene ontology(GO) analysis PON-1 ApoC4 ApoA4 complement C3and ApoE HDL3 levels in CAD patients were significantlyincreased compared to healthy controls Because ApoE levelsare reported to be lower in HDL2 from subjects with CADit is possible that redistribution of ApoE from HDL2 toHDL3 impairs cholesterol efflux and promotes formation ofmacrophage foam cells in vivo [14]

Recently the same teamused another proteomic profilingmethod with MALDI-TOF analysis of trypsin-digested pro-teins from HDL2 A partial least squares discriminant analy-sis (PLS-DA)model based onMALDI-MS signals (24 peptidesignals) containing some peptides of ApoA1 (oxidation atMet112) ApoC3 (upregulated) lipoprotein(a) (upregulated)and ApoC1 (downregulated) accurately classified CAD andcontrol subjects [8]

The HDL proteome in hemodialysis (HD) patients hasbeen investigated by iTRAQ labeling IEF peptide separation(OFFGEL Fractionator Agilent) and nano-LC-MSMS [79]Of the 303 proteins identified 122 were further selectedusing stringent criteria and among them 40 displayed dif-ferential expression in HD patients compared to healthygroups These differentially expressed proteins have beenimplicated in many functions including lipid metabolisminflammatory response the complement and coagulationcascade and endopeptidase inhibitor activity The increaseof ApoC2ApoC3 and decrease of serotransferrin in HDL of

8 BioMed Research International

HD patients compared with healthy groups were identifiedand validated Increased ApoC2 and ApoC3 imply abnormaltransfer of ApoC to VLDL and chylomicron and could be amarker of impaired HDL particle maturation Additionallythe decrease in serotransferrin may lead to decreased protec-tion against LDL oxidation

Alwaili et al used label-free quantitative proteomicsbased on spectral counting and the emPAImethod to identifynine proteins including hemoglobin subunit beta ApoA4serum amyloid A (SAA) haptoglobin-related protein (HRP)C3 gelsolin carbonic anhydrase I PGRP2 and fibronectinwith differential expression in acute coronary syndrome(ACS) patients [80] The authors speculated that elevatedSAA levels may account for improved cellular cholesterolefflux

Weichhart et al used label-free quantitative proteomicswith the peptide index method to study HDL proteomein uremic patients They determined that uremic HDL wasenriched with surfactant protein B (SP-B) ApoC2 SAA and120572-1-microglobulinbikunin precursor (AMBP) and demon-strated that SAA in uremia-HDL can promote inflammatorycytokine production [81]

Cubedo et al analyzed serum and HDL samples fromacute myocardial infraction (AMI) patients using 2DE andMALDI-TOF They discovered that transthyretin (TTR pI =56 Mw = 42 kDa) decreased in patients with high cardio-vascular risk [82] Meanwhile Huang et al [6] also appliedlabel-free quantitative proteomic approaches on HDLs inCAD patients and proposed clusterin reduction and ApoC3increase asmechanisms leading to altered effects on endothe-lial apoptosis [82]

In summary the changes in HDL protein expressiondetected by MS-based proteomic studies are observed inmany types of ASVD or diseases with high ASVD risksThe alterations could manifest in apolipoproteins or otherHDL-associated proteins which compromise HDL lipidmetabolism antioxidation anti-inflammation antiapoptosisimmune regulation or others functionsThe changes in HDLprotein quantity make HDL dysfunctional and lead to highASVD risk

7 Modification of HDL Lipoproteins asPotential Disease Markers

The quality of HDL is also an important marker for diseasedevelopment In nano-LC-MSMS analysis modificationsand their locations on a protein can be identified InMALDI-TOF-MS it is beneficial to high throughput analyzeapolipoprotein isoforms and obtain their relative abundanceratiosTherefore in some cases both techniques of nano-LC-MSMS and MALDI-TOF-MS are applied to obtain comple-mentary information ApoC1 in HDL is a potent activator ofLCAT and an inhibitor of CETP that can potentially regulateseveral lipase enzymes [83] A functional polymorphism ofApoC1 T45S was recently identified in some subjects ofAmerican Indian or Mexican ancestry [84] More recently anew full-lengthApoC1

1(67216Da) and its truncated isoform

ApoC110158401(65200Da) each around 90Da higher in mass

than expected (ApoC1 6631Da and ApoC11015840 6432Da) weredetected in a CAD cohort [85] Oxidative ApoC1 and itsoxidative-truncated form were specifically detected in HDLfrom patients with atherosclerotic vascular disease (ASVD)including CAD carotid atherosclerosis and ischemic strokeInterestingly there was no detectable oxidative ApoC1 inthe plasma of these ASVD subjects which may indicatethat oxidative ApoC1 is specific to ASVD HDL Thereforeoxidation of ApoC1 may be a useful marker for predictingCAD carotid atherosclerosis or stroke

ApoA1 is an important activator of LCAT and modifiedApoA1may compromise RCT and cause atherosclerosis [86]Oxidation atMet112 of ApoA1 inHDL enhanced by theMxxYmotif has been characterized as a sacrificial antioxidantprotecting tyrosine from chlorination [87]Myeloperoxidase-(MPO-) oxidized HDL may diminish the ability of ApoA1 toactivate LCAT because oxidized ApoA1 Met148 disrupts thecentral loop overlapping the LCAT activation domain [88]LCAT converts free cholesterol into cholesteryl esters whichare then sequestered into the HDL core for lipid metabolismLower LCAT activity could consequently aggravate choles-terol accumulation in arteries and lead to ASVD

Therefore oxidation at Met148 may be a more impor-tant factor than oxidation at Met112 in ApoA1 dysfunctionUsingMALDI-TOF we determined that high oxidation levelsat Met112 are positively correlated with oxidation level ofMet148 in vivo [9] Additionally oxidation at Met112 andMet148 is higher in ASVD uremia and diabetes mellitus(DM) patients than in normal and primary hyperlipidemia(HP) groups and oxidation at Met112 is highest in ASVDpatients Therefore oxidation at Met112 and Met148 canincrease risks of ASVD

ApoA1 can be glycated by covalent bonding of a sugarmolecule Glycation of HDL occurs in diabetes uremia andhyperglycemia [20 89] Glycated HDL is highly susceptibleto oxidation which induces endothelial cell injury anddecreases atheroprotective effects against lipid peroxidationor oxLDL toxicity [90 91] Glycated ApoA1 can reduce RCTby decreasing ABCA-1 stability or by interfering with thecontact between HDL and SR-B1 [92] a liver scavengerreceptor that facilitates uptake of cholesteryl esters fromHDL Recently glycation of ApoA1 was reported to impairits anti-inflammatory properties [93] However due to lowersensitivity of MS for negatively charged ions glycated pro-teinspeptides are not easily detected We recently used agradient SDS gel (4ndash12) to successfully separate glycatedand nonglycated ApoA1 and found that higher levels of gly-cated ApoA1 specifically appear in ASVD patients (Figure 5)Subsequent purification of glycated ApoA1 allowed the weaksignals of glycated peptides to be detected by MALDI-TOF

ApoA1 in uremia patients has been reported to be heavilycarbamylated due to the presence of high plasma urealevels [20 94] Urea degrades to cyanate and isocyanatewhich exist in equilibriumThis electrophilic pair reacts withnucleophilic amino acids such as lysine in HDL proteinsto induce protein carbamylation [95] Lysine carbamylation(carbamyllysine) in ApoA1 can induce cholesterol accumu-lation in macrophages [20] In addition to uremia smoking

BioMed Research International 9

A band nonglycated ApoA1B band glycated ApoA1 C band highly glycated ApoA1

ASVD Non-ASVD

A band

B band

C band

Figure 5 Bis-Tris (4ndash12) gel analysis of HDL samplesThe bloodwas taken from one ASVD and one non-ASVD volunteer aftergetting informed consent and the sampling protocol was approvedby the institutional review boardDetailed experimentalmethod canbe referred to in [9]

is another cause of high plasma thiocyanate which oxidizesto form cyanate and catalyzes ApoA1 carbamylation [94]In addition to oxidation glycation and carbamylation anincrease in glycosylated ApoA1 levels was recently found inpatients with AMI [96]

ApoC3 is present in three isoforms with 0ndash2 sialic acidmolecules attached ApoC3

0 ApoC3

1 and ApoC3

2 ApoC3

kinetics was measured in an in vivo study which suggestedthat all ApoC3 isoforms especially the predominant C3

1and

C32isoforms contribute to hypertriglyceridemia Addition-

ally ApoC32may be an important risk factor for cardiovascu-

lar disease because it has the most deleterious impact on LDLparticle size [19] Recently the HDL-ApoC3VLDL-ApoC3ratio has been proposed as a potential predictor for CAD [45]

In summary oxidation carbamylation glycation orothermodifications of apolipoproteins can compromise apol-ipoprotein and HDL-associated enzyme activities and resultin RCT defect The protein-modified HDL can thus lead todyslipidemia and increase the hazard of ASVD

8 Future Direction and Perspective

Due to the heterogeneity of HDL the improvement ofmethods inHDL fractioning and purification ismandatory inthe future Despite MS being a well-developed techniquethere are still pitfalls Due to low MS sensitivity for ionscarrying more negative charges it is still hard to detect neg-atively charged modification of proteins and enzymes in theHDL protein mixtures Enrichment of modified proteins orenzymes from HDL protein mixtures prior to MS analysis by

stationary phase-coatedmaterials or other purificationmeth-ods (eg PAGE and LC chromatography) could be a moresensitive approach to identify modifications and its abun-dance Recent development of targetMS-based protein quan-titation [97] can be an attractive method in the biomarkervalidation including their modifications in a large sample sizeof HDL

9 Conclusion

Emerging development of MS proteomics provides a fastand sensitive analysis to discover markers or possible HDLroles in diseases Lots of proteomic studies on HDL andsubfractionation HDL have been reported and are mainlyfocused on atherosclerosis diseases More recently HDL pro-teinmodifications have been implicated as pathogenic factorsdirectly or indirectly involved in atherosclerosis diseases

Along with the tremendous technical progress in the fieldof MS-based proteomic studies more sensitive and specificHDL modifications will be discovered and quantified Usingthese HDL biomarkers we will be able to more accuratelypredict the occurrence of ASVD

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was supported by grants from the China MedicalUniversity (CMU102-S-10) from National Science Council(NSC101-2632-B-039-001-MY3 and NSC103-2113-M-039-001-MY2) from Ministry of Health and Welfare (MOHW-104-TDU-B-212-113002) and fromAcademia Sinica Taiwan (Uro-thelial Carcinoma (BM103010089) Diabetes (BM103010095)and Stroke Biosignature (BM104010092) Projects)

References

[1] P Barter J Kastelein A Nunn et al ldquoHigh density lipopro-teins (HDLs) and atherosclerosis the unanswered questionsrdquoAtherosclerosis vol 168 no 2 pp 195ndash211 2003

[2] K-A Rye and P J Barter ldquoRegulation of high-density lipopro-tein metabolismrdquo Circulation Research vol 114 no 1 pp 143ndash156 2014

[3] W B Kannel ldquoHigh-density lipoproteins epidemiologic profileand risks of coronary artery diseaserdquo American Journal ofCardiology vol 52 no 4 pp 9Bndash12B 1983

[4] A V Khera M Cuchel M de la Llera-Moya et al ldquoCholes-terol efflux capacity high-density lipoprotein function andatherosclerosisrdquoTheNew England Journal of Medicine vol 364no 2 pp 127ndash135 2011

[5] D Bailey I Ruel A Hafiane et al ldquoAnalysis of lipid transferactivity between model nascent HDL particles and plasmalipoproteins implications for current concepts of nascent HDLmaturation and genesisrdquo The Journal of Lipid Research vol 51no 4 pp 785ndash797 2010

10 BioMed Research International

[6] Y Huang Z Wu M Riwanto et al ldquoMyeloperoxidaseparaoxonase-1 and HDL form a functional ternary complexrdquoThe Journal of Clinical Investigation vol 123 no 9 pp 3815ndash3828 2013

[7] C Li W Zhang F Zhou et al ldquoCholesteryl ester transferprotein inhibitors in the treatment of dyslipidemia a systematicreview and meta-analysisrdquo PLoS ONE vol 8 no 10 Article IDe77049 2013

[8] T Vaisar P Mayer E Nilsson X-Q Zhao R Knopp and B JPrazen ldquoHDL in humans with cardiovascular disease exhibits aproteomic signaturerdquo Clinica Chimica Acta vol 411 no 13-14pp 972ndash979 2010

[9] C-T Chang H-Y Liao C-M Chang et al ldquoOxidized ApoC1on MALDI-TOF and glycated-ApoA1 band on gradient gel aspotential diagnostic tools for atherosclerotic vascular diseaserdquoClinica Chimica Acta vol 420 pp 69ndash75 2013

[10] M Holzer M Gauster T Pfeifer et al ldquoProtein carbamylationrenders high-density lipoprotein dysfunctionalrdquo Antioxidantsand Redox Signaling vol 14 no 12 pp 2337ndash2346 2011

[11] R J Havel H A Eder and J H Bragdon ldquoThe distribution andchemical composition of ultracentrifugally separated lipopro-teins in human serumrdquoThe Journal of Clinical Investigation vol34 no 9 pp 1345ndash1353 1955

[12] Y Abe M Fornage C-Y Yang et al ldquoL5 the most electroneg-ative subfraction of plasma LDL induces endothelial vascularcell adhesion molecule 1 and CXC chemokines which mediatemononuclear leukocyte adhesionrdquo Atherosclerosis vol 192 no1 pp 56ndash66 2007

[13] A S Shah L Tan J L Long and W S Davidson ldquoPro-teomic diversity of high density lipoproteins our emergingunderstanding of its importance in lipid transport and beyondrdquoJournal of Lipid Research vol 54 no 10 pp 2575ndash2585 2013

[14] T Vaisar S Pennathur P S Green et al ldquoShotgun proteomicsimplicates protease inhibition and complement activation in theantiinflammatory properties of HDLrdquo The Journal of ClinicalInvestigation vol 117 no 3 pp 746ndash756 2007

[15] B J Arsenault I Lemieux J-PDespres et al ldquoHDLparticle sizeand the risk of coronary heart disease in apparently healthymenand women the EPIC-Norfolk prospective population studyrdquoAtherosclerosis vol 206 no 1 pp 276ndash281 2009

[16] J-Y Hsieh C-T Chang M T Huang et al ldquoBiochemical andfunctional characterization of charge-defined subfractions ofhigh-density lipoprotein fromnormal adultsrdquoAnalytical Chem-istry vol 85 no 23 pp 11440ndash11448 2013

[17] D T A Eisenberg CW Kuzawa andMGHayes ldquoWorldwideallele frequencies of the human apolipoprotein E gene climatelocal adaptations and evolutionary historyrdquo American Journalof Physical Anthropology vol 143 no 1 pp 100ndash111 2010

[18] R W Mahley T L Innerarity S C Rall Jr and K HWeisgraber ldquoPlasma lipoproteins apolipoprotein structure andfunctionrdquo Journal of Lipid Research vol 25 no 12 pp 1277ndash1294 1984

[19] J-F Mauger P Couture N Bergeron and B LamarcheldquoApolipoprotein C-III isoforms kinetics and relative implica-tion in lipid metabolismrdquo Journal of Lipid Research vol 47 no6 pp 1212ndash1218 2006

[20] D El-Gamal M Holzer M Gauster et al ldquoCyanate is a novelinducer of endothelial ICAM-1 expressionrdquo Antioxidants andRedox Signaling vol 16 no 2 pp 129ndash137 2012

[21] K-A Rye N J Hime and P J Barter ldquoThe influence ofcholesteryl ester transfer protein on the composition size and

structure of spherical reconstituted high density lipoproteinsrdquoThe Journal of Biological Chemistry vol 270 no 1 pp 189ndash1961995

[22] L Dumont T Gautier J-P de Barros et al ldquoMolecularmechanism of the blockade of plasma cholesteryl ester transferprotein by its physiological inhibitor apolipoprotein CIrdquo TheJournal of Biological Chemistry vol 280 no 45 pp 38108ndash381162005

[23] Y Shen A Lookene S Nilsson and G Olivecrona ldquoFunctionalanalyses of human apolipoprotein CII by site-directed muta-genesis identification of residues important for activation oflipoprotein lipaserdquo Journal of Biological Chemistry vol 277 no6 pp 4334ndash4342 2002

[24] M de la Llera Moya F C McGillicuddy C C Hinkle etal ldquoInflammation modulates human HDL composition andfunction in vivordquo Atherosclerosis vol 222 no 2 pp 390ndash3942012

[25] M Holzer R Birner-Gruenberger T Stojakovic et al ldquoUremiaalters HDL composition and functionrdquo Journal of the AmericanSociety of Nephrology vol 22 no 9 pp 1631ndash1641 2011

[26] M Holzer P Wolf M Inzinger et al ldquoAnti-psoriatic therapyrecovers high-density lipoprotein composition and functionrdquoJournal of Investigative Dermatology vol 134 no 3 pp 635ndash6422014

[27] P-H GroopM CThomasM Rosengard-Barlund et al ldquoHDLcomposition predicts new-onset cardiovascular disease inpatients with type 1 diabetesrdquo Diabetes Care vol 30 no 10 pp2706ndash2707 2007

[28] N Shuhei S Soderlund M Jauhiainen and M-R TaskinenldquoEffect of HDL composition and particle size on the resistanceof HDL to the oxidationrdquo Lipids in Health and Disease vol 9article 104 2010

[29] C Esau S Davis S F Murray et al ldquomiR-122 regulation oflipid metabolism revealed by in vivo antisense targetingrdquo CellMetabolism vol 3 no 2 pp 87ndash98 2006

[30] K J Rayner Y Suarez A Davalos et al ldquoMiR-33 contributes tothe regulation of cholesterol homeostasisrdquo Science vol 328 no5985 pp 1570ndash1573 2010

[31] M V Pahl Z Ni L Sepassi H Moradi and N D VazirildquoPlasmaphospholipid transfer protein cholesteryl ester transferprotein and lecithincholesterol acyltransferase in end-stagerenal disease (ESRD)rdquoNephrology Dialysis Transplantation vol24 no 8 pp 2541ndash2546 2009

[32] D M Shih Y-R Xia X-P Wang et al ldquoCombined serumparaoxonase knockoutapolipoprotein E knockout mice exhibitincreased lipoprotein oxidation and atherosclerosisrdquo The Jour-nal of Biological Chemistry vol 275 no 23 pp 17527ndash175352000

[33] M A Kennedy G C Barrera K Nakamura et al ldquoABCG1 hasa critical role in mediating cholesterol efflux to HDL andpreventing cellular lipid accumulationrdquo Cell Metabolism vol 1no 2 pp 121ndash131 2005

[34] N Terasaka M Westerterp J Koetsveld et al ldquoATP-bindingcassette transporter G1 and high-density lipoprotein promoteendothelial NO synthesis through a decrease in the interactionof caveolin-1 and endothelial NO synthaserdquo ArteriosclerosisThrombosis and Vascular Biology vol 30 no 11 pp 2219ndash22252010

[35] L Yvan-Charvet C Welch T A Pagler et al ldquoIncreasedinflammatory gene expression in ABC transporter-deficientmacrophages free cholesterol accumulation increased sig-naling via toll-like receptors and neutrophil infiltration of

BioMed Research International 11

atherosclerotic lesionsrdquo Circulation vol 118 no 18 pp 1837ndash1847 2008

[36] J K Kruit N Wijesekara C Westwell-Roper et al ldquoLoss ofboth ABCA1 and ABCG1 results in increased disturbances inislet sterol homeostasis inflammation and impaired beta-cellfunctionrdquo Diabetes vol 61 no 3 pp 659ndash664 2012

[37] I S Yuhanna Y Zhu B E Cox et al ldquoHigh-density lipoproteinbinding to scavenger receptor-BI activates endothelial nitricoxide synthaserdquoNatureMedicine vol 7 no 7 pp 853ndash857 2001

[38] G Assmann and J-R Nofer ldquoAtheroprotective effects of high-density lipoproteinsrdquo Annual Review of Medicine vol 54 pp321ndash341 2003

[39] D Seetharam C Mineo A K Gormley et al ldquoHigh-densitylipoprotein promotes endothelial cell migration and reendothe-lialization via scavenger receptor-B type IrdquoCirculation Researchvol 98 no 1 pp 63ndash72 2006

[40] T F Luscher U Landmesser A von Eckardstein and AM Fogelman ldquoHigh-density lipoprotein vascular protectiveeffects dysfunction and potential as therapeutic targetrdquo Circu-lation Research vol 114 no 1 pp 171ndash182 2014

[41] L A Cuellar E D Prieto L V Cabaleiro and H A GardaldquoApolipoprotein A-I configuration and cell cholesterol effluxactivity of discoidal lipoproteins depend on the reconstitutionprocessrdquo Biochimica et Biophysica Acta vol 1841 no 1 pp 180ndash189 2014

[42] M Krieger ldquoCharting the fate of the ldquogood cholesterolrdquo iden-tification and characterization of the high-density lipoproteinreceptor SR-BIrdquo Annual Review of Biochemistry vol 68 pp523ndash558 1999

[43] N Y Gbandjaba N Ghalim M Hassar et al ldquoParaoxonaseactivity in healthy diabetic and hemodialysis patientsrdquo ClinicalBiochemistry vol 45 no 6 pp 470ndash474 2012

[44] T van Himbergen M Roest F de Waart et al ldquoParaoxonasegenotype LDL-oxidation and carotid atherosclerosis in malelife-long smokersrdquo Free Radical Research vol 38 no 6 pp 553ndash560 2004

[45] L D Cacciagiu A I Gonzalez L G Rosso et al ldquoHDL-associated enzymes and proteins in hemodialysis patientsrdquoClinical Biochemistry vol 45 no 3 pp 243ndash248 2012

[46] M Madjid M Ali and J T Willerson ldquoLipoprotein-associatedphospholipase A2 as a novel risk marker for cardiovasculardisease a systematic review of the literaturerdquo Texas HeartInstitute Journal vol 37 no 1 pp 25ndash39 2010

[47] A Matsuzawa K Hattori J Aoki H Arai and K InoueldquoProtection against oxidative stress-induced cell death by intra-cellular platelet-activating factor-acetylhydrolase IIrdquo Journal ofBiological Chemistry vol 272 no 51 pp 32315ndash32320 1997

[48] A D Mooradian ldquoDyslipidemia in type 2 diabetes mellitusrdquoNature Clinical Practice Endocrinology and Metabolism vol 5no 3 pp 150ndash159 2009

[49] J J Chillaron J A Flores le-Roux D Benaiges and J Pedro-Botet ldquoType 1 diabetesmetabolic syndrome and cardiovascularriskrdquo Metabolism Clinical and Experimental vol 63 no 2 pp181ndash187 2014

[50] M J Cziraky K E Watson R L Talbert and P Stella ldquoTar-geting low HDL-cholesterol to decrease residual cardiovascularrisk in the managed care settingrdquo Journal of Managed CarePharmacy vol 14 supplement 8 pp S3ndashS28 2008

[51] D J Gordon J L Probstfield R J Garrison et al ldquoHigh-density lipoprotein cholesterol and cardiovascular disease Fourprospective American studiesrdquo Circulation vol 79 no 1 pp 8ndash15 1989

[52] M Briel I Ferreira-Gonzalez J J You et al ldquoAssociationbetween change in high density lipoprotein cholesterol andcardiovascular disease morbidity and mortality systematicreview and meta-regression analysisrdquo British Medical Journalvol 338 no 7693 article b92 2009

[53] L Calabresi and G Franceschini ldquoLecithin cholesterol acyl-transferase high-density lipoproteins and atheroprotection inhumansrdquo Trends in Cardiovascular Medicine vol 20 no 2 pp50ndash53 2010

[54] J C van Capelleveen H B Brewer J J P Kastelein andG K Hovingh ldquoNovel therapies focused on the high-densitylipoprotein particlerdquo Circulation Research vol 114 no 1 pp193ndash204 2014

[55] S Stukas J Robert and C L Wellington ldquoHigh-density lipo-proteins and cerebrovascular integrity in Alzheimerrsquos diseaserdquoCell Metabolism vol 19 no 4 pp 574ndash591 2014

[56] H Berrougui S Loued and A Khalil ldquoPurified humanparaoxonase-1 interacts with plasma membrane lipid rafts andmediates cholesterol efflux from macrophagesrdquo Free RadicalBiology and Medicine vol 52 no 8 pp 1372ndash1381 2012

[57] M Roest T M van Himbergen A B Barendrecht P H MPeeters Y T van der Schouw and H A M Voorbij ldquoGeneticand environmental determinants of the PON-1 phenotyperdquoEuropean Journal of Clinical Investigation vol 37 no 3 pp 187ndash196 2007

[58] N D Vaziri ldquoCauses of dysregulation of lipid metabolism inchronic renal failurerdquo Seminars in Dialysis vol 22 no 6 pp644ndash651 2009

[59] N A Karp andK S Lilley ldquoInvestigating sample pooling strate-gies for DIGE experiments to address biological variabilityrdquoProteomics vol 9 no 2 pp 388ndash397 2009

[60] P J Barter S Nicholls K A Rye G M Anantharamaiah MNavab and A M Fogelman ldquoAntiinflammatory properties ofHDLrdquo Circulation Research vol 95 no 8 pp 764ndash772 2004

[61] D Chelius and P V Bondarenko ldquoQuantitative profiling ofproteins in complex mixtures using liquid chromatography andmass spectrometryrdquo Journal of Proteome Research vol 1 no 4pp 317ndash323 2002

[62] L Zheng B Nukuna M-L Brennan et al ldquoApolipoprotein A-I is a selective target for myeloperoxidase-catalyzed oxidationand functional impairment in subjects with cardiovasculardiseaserdquoThe Journal of Clinical Investigation vol 114 no 4 pp529ndash541 2004

[63] S Arora M Husain D Kumar et al ldquoHuman immun-odeficiency virus downregulates podocyte apoE expressionrdquoAmerican Journal of Physiology Renal Physiology vol 297 no3 pp F653ndashF661 2009

[64] M D Sury J-X Chen and M Selbach ldquoThe SILAC fly allowsfor accurate protein quantification in vivordquo Molecular andCellular Proteomics vol 9 no 10 pp 2173ndash2183 2010

[65] M Kruger M Moser S Ussar et al ldquoSILAC mouse for quan-titative proteomics uncovers kindlin-3 as an essential factor forred blood cell functionrdquo Cell vol 134 no 2 pp 353ndash364 2008

[66] T Geiger J R Wisniewski J Cox et al ldquoUse of stable isotopelabeling by amino acids in cell culture as a spike-in standard inquantitative proteomicsrdquoNature Protocols vol 6 no 2 pp 147ndash157 2011

[67] A Jaleel G C Henderson B J Madden et al ldquoIdentification ofde novo synthesized and relatively older proteins aAcceleratedoxidative damage to de novo synthesized apolipoprotein A-1 intype 1 diabetesrdquo Diabetes vol 59 no 10 pp 2366ndash2374 2010

12 BioMed Research International

[68] A Lapolla M Brioschi C Banfi et al ldquoNonenzymaticallyglycated lipoprotein ApoA-I in plasma of diabetic and nephro-pathic patientsrdquo Annals of the New York Academy of Sciencesvol 1126 pp 295ndash299 2008

[69] N Tang P Tornatore and S R Weinberger ldquoCurrent devel-opments in SELDI affinity technologyrdquo Mass SpectrometryReviews vol 23 no 1 pp 34ndash44 2004

[70] M F Brodde S J A Korporaal G Herminghaus et al ldquoNativehigh-density lipoproteins inhibit platelet activation via scav-enger receptor BI role of negatively charged phospholipidsrdquoAtherosclerosis vol 215 no 2 pp 374ndash382 2011

[71] J D Otvos ldquoMeasurement of lipoprotein subclass profiles bynuclear magnetic resonance spectroscopyrdquo Clinical Laboratoryvol 48 no 3-4 pp 171ndash180 2002

[72] P J Blanche E L Gong T M Forte and A V Nichols ldquoChar-acterization of human high-density lipoproteins by gradient gelelectrophoresisrdquo Biochimica et Biophysica Acta vol 665 no 3pp 408ndash419 1981

[73] R S Rosenson H B Brewer Jr M J Chapman et alldquoHDL measures particle heterogeneity proposed nomencla-ture and relation to atherosclerotic cardiovascular eventsrdquoClinical Chemistry vol 57 no 3 pp 392ndash410 2011

[74] J-Y Lee L Lanningham-Foster E Y Boudyguina et al ldquoPre120573high density lipoprotein has two metabolic fates in humanapolipoprotein A-I transgenic micerdquo Journal of Lipid Researchvol 45 no 4 pp 716ndash728 2004

[75] B F Asztalos C H Sloop L Wong and P S Roheim ldquoTwo-dimensional electrophoresis of plasma lipoproteins recogni-tion of new apo A-I-containing subpopulationsrdquo Biochimica etBiophysica Acta vol 1169 no 3 pp 291ndash300 1993

[76] P Davidsson J Hulthe B Fagerberg and G Camejo ldquoPro-teomics of apolipoproteins and associated proteins fromplasmahigh-density lipoproteinsrdquo Arteriosclerosis Thrombosis andVascular Biology vol 30 no 2 pp 156ndash163 2010

[77] T Vaisar ldquoProteomics investigations of HDL challenges andpromiserdquoCurrentVascular Pharmacology vol 10 no 4 pp 410ndash421 2012

[78] I Jorge E Burillo R Mesa et al ldquoThe human HDL proteomedisplays high inter-individual variability and is altered dynam-ically in response to angioplasty-induced atheroma plaquerupturerdquo Journal of Proteomics vol 106 pp 61ndash73 2014

[79] A Mange A Goux S Badiou et al ldquoHdl proteome inhemodialysis patients a quantitative nanoflow liquidchromatography-tandem mass spectrometry approachrdquoPLoS ONE vol 7 no 3 Article ID e34107 2012

[80] K Alwaili D Bailey Z Awan et al ldquoThe HDL proteome inacute coronary syndromes shifts to an inflammatory profilerdquoBiochimica et Biophysica Acta Molecular and Cell Biology ofLipids vol 1821 no 3 pp 405ndash415 2012

[81] T Weichhart C Kopecky M Kubicek et al ldquoSerum amyloidA in uremic HDL promotes inflammationrdquo Journal of theAmerican Society of Nephrology vol 23 no 5 pp 934ndash947 2012

[82] J Cubedo T Padro R Alonso J Cinca P Mata and LBadimon ldquoDifferential proteomic distribution of TTR (pre-albumin) forms in serum and HDL of patients with highcardiovascular riskrdquoAtherosclerosis vol 222 no 1 pp 263ndash2692012

[83] K Conde-Knape A Bensadoun J H Sobel J S Cohn andN S Shachter ldquoOverexpression of apoC-I in apoE-null micesevere hypertriglyceridemia due to inhibition of hepatic lipaserdquoJournal of Lipid Research vol 43 no 12 pp 2136ndash2145 2002

[84] M S Wroblewski J T Wilson-Grady M B Martinez et alldquoA functional polymorphism of apolipoprotein C1 detected bymass spectrometryrdquo FEBS Journal vol 273 no 20 pp 4707ndash4715 2006

[85] D Moore C McNeal and R Macfarlane ldquoIsoforms ofapolipoprotein C-I associated with individuals with coronaryartery diseaserdquo Biochemical and Biophysical Research Commu-nications vol 404 no 4 pp 1034ndash1038 2011

[86] C J Fielding V G Shore and P E Fielding ldquoLecithincholesterol acyltransferase effects of substrate compositionupon enzyme activityrdquo Biochimica et Biophysica Acta vol 270no 4 pp 513ndash518 1972

[87] B Shao M N Oda C Bergt et al ldquoMyeloperoxidase impairsABCA1-dependent cholesterol efflux through methionine oxi-dation and site-specific tyrosine chlorination of apolipoproteinA-Irdquo The Journal of Biological Chemistry vol 281 no 14 pp9001ndash9004 2006

[88] B Shao G Cavigiolio N Brot M N Oda and J W HeineckeldquoMethionine oxidation impairs reverse cholesterol transport byapolipoprotein A-Irdquo Proceedings of the National Academy ofSciences of the United States of America vol 105 no 34 pp12224ndash12229 2008

[89] A Lapolla M Brioschi C Banfi et al ldquoOn the search forglycated lipoprotein ApoA-I in the plasma of diabetic andnephropathic patientsrdquo Journal of Mass Spectrometry vol 43no 1 pp 74ndash81 2008

[90] A Hoang A J Murphy M T Coughlan et al ldquoAdvancedglycation of apolipoprotein A-I impairs its anti-atherogenicpropertiesrdquo Diabetologia vol 50 no 8 pp 1770ndash1779 2007

[91] C C Hedrick S R Thorpe M-X Fu et al ldquoGlycation impairshigh-density lipoprotein functionrdquo Diabetologia vol 43 no 3pp 312ndash320 2000

[92] A P MacHado R S Pinto Z P Moyses E R NakandakareE C R Quintao and M Passarelli ldquoAminoguanidine andmetformin prevent the reduced rate of HDL-mediated cellcholesterol efflux induced by formation of advanced glycationend productsrdquo International Journal of Biochemistry and CellBiology vol 38 no 3 pp 392ndash403 2006

[93] E Nobecourt F Tabet G Lambert et al ldquoNonenzymatic glyca-tion impairs the antiinflammatory properties of apolipoproteinA-Irdquo Arteriosclerosis Thrombosis and Vascular Biology vol 30no 4 pp 766ndash772 2010

[94] N Terasaka N Wang L Yvan-Charvet and A R Tall ldquoHigh-density lipoprotein protects macrophages from oxidized low-density lipoprotein-induced apoptosis by promoting effluxof 7-ketocholesterol via ABCG1rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 104 no38 pp 15093ndash15098 2007

[95] R A Koeth K Kalantar-Zadeh ZWang X FuW HW Tangand S L Hazen ldquoProtein carbamylation predicts mortality inESRDrdquo Journal of the American Society of Nephrology vol 24no 5 pp 853ndash861 2013

[96] J Cubedo T Padro and L Badimon ldquoGlycoproteomeof humanapolipoprotein A-I N- and O-glycosylated forms are increasedin patients with acute myocardial infarctionrdquo TranslationalResearch vol 164 no 3 pp 209ndash222 2014

[97] Y Xiao L Guo and Y Wang ldquoA targeted quantitative pro-teomics strategy for global kinome profiling of cancer cells andtissuesrdquo Molecular and Cellular Proteomics vol 13 no 4 pp1065ndash1075 2014

[98] Y Tan T R Liu S W Hu et al ldquoAcute coronary syndromeremodels the protein cargo and functions of high-density

BioMed Research International 13

lipoprotein subfractionsrdquo PLoS ONE vol 9 no 4 Article IDe94264 2014

[99] M Riwanto L Rohrer B Roschitzki et al ldquoAltered activationof endothelial anti- and proapoptotic pathways by high-densitylipoprotein from patients with coronary artery disease roleof high-density lipoprotein-proteome remodelingrdquo Circulationvol 127 no 8 pp 891ndash904 2013

Submit your manuscripts athttpwwwhindawicom

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