title: Quantitative N-linked glycoproteomics of myocardial ischemia and reperfusion injury reveals early remodeling in the extracellular environment.
abstract: Extracellular and cell surface proteins are generally modified with N-linked glycans and glycopeptide enrichment is an attractive tool to analyze these proteins. The role of N-linked glycoproteins in cardiovascular disease, particularly ischemia and reperfusion injury, is poorly understood. Observation of glycopeptides by mass spectrometry is challenging due to the presence of abundant, nonglycosylated analytes, and robust methods for purification are essential. We employed digestion with multiple proteases to increase glycoproteome coverage coupled with parallel glycopeptide enrichments using hydrazide capture, titanium dioxide, and hydrophilic interaction liquid chromatography with and without an ion-pairing agent. Glycosylated peptides were treated with PNGase F and analyzed by liquid chromatography-MS/MS. This allowed the identification of 1556 nonredundant N-linked glycosylation sites, representing 972 protein groups from ex vivo rat left ventricular myocardium. False positive "glycosylations" were observed on 44 peptides containing a deamidated Asn-Asp in the N-linked sequon by analysis of samples without PNGase F treatment. We used quantitation via isobaric tags for relative and absolute quantitation (iTRAQ) and validation with dimethyl labeling to analyze changes in glycoproteins from tissue following prolonged ischemia and reperfusion (40 mins ischemia and 20 mins reperfusion) indicative of myocardial infarction. The iTRAQ approach revealed 80 of 437 glycopeptides with altered abundance, while dimethyl labeling confirmed 46 of these and revealed an additional 62 significant changes. These were mainly from predicted extracellular matrix and basement membrane proteins that are implicated in cardiac remodeling. Analysis of N-glycans released from myocardial proteins suggest that the observed changes were not due to significant alterations in N-glycan structures. Altered proteins included the collagen-laminin-integrin complexes and collagen assembly enzymes, cadherins, mast cell proteases, proliferation-associated secreted protein acidic and rich in cysteine, and microfibril-associated proteins. The data suggest that cardiac remodeling is initiated earlier during reperfusion than previously hypothesized.
authors: Discipline of Pathology, School of Medical Sciences, The University of Sydney, New South Wales, Australia 2006.
authors: Benjamin L
authors: BL
authors: Parker
authors: Giuseppe
authors: G
authors: Palmisano
authors: Alistair V G
authors: AV
authors: Edwards
authors: Melanie Y
authors: MY
authors: White
authors: Kasper
authors: K
authors: Engholm-Keller
authors: Albert
authors: A
authors: Lee
authors: Nichollas E
authors: NE
authors: Scott
authors: Daniel
authors: D
authors: Kolarich
authors: Brett D
authors: BD
authors: Hambly
authors: Nicolle H
authors: NH
authors: Packer
authors: Martin R
authors: MR
authors: Larsen
authors: Stuart J
authors: SJ
authors: Cordwell
mesh_terms: D000818:Animals; D002240:Carbohydrate Sequence; D002852:Chromatography, Ion Exchange; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006023:Glycoproteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D006321:Heart / Q000503:physiopathology; D006439:Hemodynamics; D066298:In Vitro Techniques; D008297:Male; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D017202:Myocardial Ischemia / Q000378:metabolism*; D015428:Myocardial Reperfusion Injury / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D011134:Polysaccharides / Q000737:chemistry / Q000302:isolation & purification; D059748:Proteolysis; D020543:Proteome / Q000378:metabolism; D040901:Proteomics; D051381:Rats; D011917:Rats, Inbred Lew; D053719:Tandem Mass Spectrometry; D020257:Ventricular Remodeling
chemical_list: D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D011134:Polysaccharides; D020543:Proteome