title: Microparticle surface protein are associated with experimental venous thrombosis: a preliminary study.
abstract: Microparticles are small membrane vesicles released from activated cells and are associated with thrombosis and inflammation. Microparticle contain a unique subset of surface protein derived form the parent cell and may be responsible for their diverse biological functions. To identify these proteins, juvenile baboons (Papio anubis, n = 4) underwent iliac vein thrombosis with 6-hour balloon occlusion. Plasma samples were taken at baselines and at 2 days postthrombosis for microparticle analysis. Microparticles were extracted from platelet-poor plasma, digest separately with trypsin and tagged using isobaric tagging for relative and absolute quantitation reagents. The digests were subjected to 2-dimensional liquid chromatographic separation followed by matrix-assisted laser desorption/ionization tandem mass spectrometry. Peak lists were generated and searched against all primate sequences. For protein identity, a minimum of 2 peptides at 95% confidence interval was required. Later, isobaric tagging for relative and absolute quantitation ratios were generated comparing relative protein level of day 2 to baseline. The proteomic analysis was performed twice for each blood sample, totaling 8 experiments. Proteins were considered elevated of depressed if the isobaris tagging for relative and absolute quantitation ratio deviated by 20% changes from normal and a P value less than .05. Significantly, 7 proteins were differentially expressed on day 2 compared to baseline, and appeared in at least 3 animals and regulated in at least 4 experiment. Among these 7 proteins, upregulated proteins include various forms of fibrinogen and alpha-1-antichymotrypsin and downregulated proteins include immunoglobulins. These proteins influence thrombosis and inflammation through hemostatic plug formation (fibrinogen), inhibiting neutrophil adhesion (alpha-1-antichymoptrypsin), and immunoregulation (immunoglobulins). Further studies are needed to confirm the mechanistic role of these proteins in the pathogenesis of venous thrombosis.
authors.affiliation: Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Newaj M
authors.initials: NM
authors.lastname: Abdullah
authors.forename: Maureen
authors.initials: M
authors.lastname: Kachman
authors.forename: Angela
authors.initials: A
authors.lastname: Walker
authors.forename: Angela E
authors.initials: AE
authors.lastname: Hawley
authors.forename: Shriley K
authors.initials: SK
authors.lastname: Wrobleski
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Myers
authors.forename: John R
authors.initials: JR
authors.lastname: Strahler
authors.forename: Philip C
authors.initials: PC
authors.lastname: Andrews
authors.forename: Goerge C
authors.initials: GC
authors.lastname: Michailidis
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ramacciotti
authors.forename: Peter K
authors.initials: PK
authors.lastname: Henke
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Wakefield
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods; D015180:Electrophoresis, Gel, Two-Dimensional; D005340:Fibrinogen / Q000378:metabolism; D023421:Models, Animal; D019007:P-Selectin / Q000378:metabolism; D010215:Papio; D010316:Particle Size; D011506:Proteins / Q000378:metabolism*; D040901:Proteomics / Q000379:methods; D013499:Surface Properties; D020246:Venous Thrombosis / Q000097:blood*
chemical_list: D019007:P-Selectin; D011506:Proteins; D005340:Fibrinogen