Proteomics of microparticles after deep venous thrombosis.
BACKGROUND
Microparticles (MP) are submicron size membrane vesicles released from activated cells that are associated with thrombosis and inflammation. MP present diverse biological expressions that may be linked to a unique subset of proteins derived from their origin cells.


METHODS
To identify these proteins, plasma samples were taken from 9 patients with deep venous thrombosis (DVT) documented by duplex ultrasound, 9 with leg pain but negative for DVT by duplex, and 6 healthy controls without a history of thrombosis, for fold variation. MP were extracted from platelet-poor plasma, digested separately with trypsin and tagged using iTRAQ reagents. The digests were subjected to 2-D LC separation followed by MALDI tandem mass spectrometry. Peak lists were generated and searched against all human sequences. For protein identification, a minimum of two peptides at 95% confidence was required. Later, iTRAQ ratios were generated comparing relative protein levels of DVT patients to baseline. The proteomic analysis was performed twice for each blood sample. Proteins were considered elevated or depressed if the iTRAQ ratio (R) deviated by 20% change from normal and a p-value less than 0.05.


RESULTS
Two proteins (Galectin-3 Binding Protein, [Gal3BP], R=1.76 and Alpha-2 macroglobulin [A2M] R=1.57) were differentially expressed on DVT patients. Nine proteins were depleted including fibrinogen beta and gamma chain precursors (R=0.65).


CONCLUSIONS
These proteins influence thrombosis through inflammation, cell shedding, inhibition of fibrinolysis and hemostatic plug formation. Further studies are needed to confirm the mechanistic role of these proteins in the pathogenesis of venous thrombosis in humans.
Jobst Vascular Research Laboratory, Section of Vascular Surgery, Cardiovascular Center, Department of Surgery, University of Michigan, Ann Arbor, MI, USA. erama@med.umich.edu
Eduardo
E
Ramacciotti
Angela E
AE
Hawley
Shirley K
SK
Wrobleski
Daniel D
DD
Myers
John R
JR
Strahler
Philip C
PC
Andrews
Kenneth E
KE
Guire
Peter K
PK
Henke
Thomas W
TW
Wakefield
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002352:Carrier Proteins / Q000032:analysis / Q000378:metabolism; D016022:Case-Control Studies; D055252:Cell-Derived Microparticles / Q000737:chemistry*; D006023:Glycoproteins / Q000032:analysis / Q000378:metabolism; D006487:Hemostasis; D006801:Humans; D007249:Inflammation; D040901:Proteomics / Q000379:methods*; D020246:Venous Thrombosis / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D000511:alpha-Macroglobulins / Q000032:analysis / Q000378:metabolism*; D016326:Extracellular Matrix Proteins
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002352:Carrier Proteins; D006023:Glycoproteins; D000511:alpha-Macroglobulins; C081856:LGALS3BP protein, human; D016326:Extracellular Matrix Proteins