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Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
Factor-V expression in platelets from human megakaryocytic culture
Adele Giampaolo1, Francesca Vulcano, Giampiero Macioce
1Section of Transfusion Methodologies, Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
British Journal of Haematology
|December 21, 2004
Summary
Human megakaryocytes synthesize platelet-factor-V, a protein crucial for blood clotting. This factor is expressed late in megakaryocyte development and is also found in mature platelets.
Area of Science:
- Hematology
- Molecular Biology
- Cell Biology
Background:
- The cellular origin of platelet-factor-V (PFV) has been a long-standing question in hematology.
- Understanding PFV synthesis is critical for comprehending hemostasis and thrombosis.
Purpose of the Study:
- To determine if human megakaryocytes synthesize platelet-factor-V.
- To identify the specific stage of megakaryocyte development at which PFV is expressed.
Main Methods:
- Utilized in vitro-generated human megakaryocytes capable of producing platelets.
- Analyzed Factor-V gene expression using quantitative PCR.
- Detected Factor-V protein in megakaryocytes and platelets via immunofluorescence, Western blotting, and flow cytometry.
Main Results:
- The Factor-V gene was found to be silent in early progenitor and precursor cells.
- Factor-V gene expression was initiated in the late culture phase of megakaryocytes.
- Factor-V protein was detected in mature proplatelet-bearing megakaryocytes and subsequently in platelets.
- The absence of other cell types in the culture system confirmed megakaryocytes as the source of PFV.
Conclusions:
- Human megakaryocytes definitively synthesize platelet-factor-V.
- PFV synthesis occurs late in megakaryocyte differentiation.
- This finding clarifies the origin of PFV and its presence in platelets.
