title: High precision platelet releasate definition by quantitative reversed protein profiling--brief report.
abstract: OBJECTIVE
  Platelet activation and subsequent protein release play an important role in healthy hemostasis and inflammatory responses, yet the identity and quantity of proteins in the platelet releasate are still debated. Here, we present a reversed releasate proteomics approach to determine unambiguously and quantitatively proteins released from activated platelets.
  
  
  RESULTS
  Isolated platelets were mock and fully stimulated after which the released proteins in the supernatant were removed. Using high-end proteomics technology (2D chromatography, stable isotope labeling, electron transfer dissociation, and high collision dissociation fragmentation) allowed us to quantitatively discriminate the released proteins from uncontrolled lysis products. Monitoring the copy numbers of ≈ 4500 platelet proteins, we observed that after stimulation via thrombin and collagen, only 124 (<3%) proteins were significantly released (P<0.05). The released proteins span a concentration range of ≥ 5 orders, as confirmed by ELISA. The released proteins were highly enriched in secretion tags and contained all known factors at high concentrations (>100 ng/mL, eg, thrombospondin, von Willebrand factor, and platelet factor 4). Interestingly, in the lower concentration range of the releasate many novel factors were identified.
  
  
  CONCLUSIONS
  Our reversed releasate dataset forms the first unambiguous, in depth repository for molecular factors released by platelets.
authors: Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.
authors: Patrick
authors: P
authors: Wijten
authors: Thijs
authors: T
authors: van Holten
authors: Liy Liy
authors: LL
authors: Woo
authors: Onno B
authors: OB
authors: Bleijerveld
authors: Mark
authors: M
authors: Roest
authors: Albert J R
authors: AJ
authors: Heck
authors: Arjen
authors: A
authors: Scholten
mesh_terms: D001792:Blood Platelets / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D002853:Chromatography, Liquid; D003094:Collagen / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007553:Isotope Labeling; D015539:Platelet Activation; D011506:Proteins / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D053719:Tandem Mass Spectrometry; D013917:Thrombin / Q000378:metabolism
chemical_list: D011506:Proteins; D003094:Collagen; D013917:Thrombin
keywords: mass spectrometry; platelet; platelet activation; proteomics