Platelets Contain Tissue Factor Pathway Inhibitor-2 Derived from Megakaryocytes and Inhibits Fibrinolysis

Autor: Sathya-Moorthy Ponnuraj, Denis Evseenko, Rodney M. Camire, Harvey R. Herschman, Anne K. Zaiss, Yogesh Kumar, Kanagasabai Vadivel, Matthew W. Bunce, S. Paul Bajaj, Ling Wu, Madhu S. Bajaj
Rok vydání: 2014
Předmět:
Plasmin
medicine.medical_treatment
Protease Inhibitor
Plasma protein binding
Ligands
Cardiovascular
Medical and Health Sciences
Biochemistry
Pregnancy
Platelet
education.field_of_study
Chemistry
Fibrinolysis
Hematology
Biological Sciences
Fetal Blood
Coagulation
Protein Structure and Folding
Female
Megakaryocytes
circulatory and respiratory physiology
Protein Binding
medicine.drug
Blood Platelets
Platelet Membrane Glycoprotein IIb
Protein Structure
Biochemistry & Molecular Biology
Lipoproteins
1.1 Normal biological development and functioning
Bone Marrow Cells
Tissue factor
Underpinning research
medicine
Humans
Protease Inhibitors
education
Blood Coagulation
Molecular Biology
Glycoproteins
Hemostasis
urogenital system
Cell Biology
Kallikrein
Surface Plasmon Resonance
Molecular biology
Tissue-factor-pathway inhibitor 2
Protein Structure
Tertiary
Gene Expression Regulation
Chemical Sciences
Tertiary
Zdroj: The Journal of biological chemistry, vol 289, iss 45
ISSN: 0021-9258
Popis: Tissue factor pathway inhibitor-2 (TFPI-2) is a homologue of TFPI-1 and contains three Kunitz-type domains and a basic C terminus region. The N-terminal domain of TFPI-2 is the only inhibitory domain, and it inhibits plasma kallikrein, factor XIa, and plasmin. However, plasma TFPI-2 levels are negligible (≤20 pM) in the context of influencing clotting or fibrinolysis. Here, we report that platelets contain significant amounts of TFPI-2 derived from megakaryocytes. We employed RT-PCR, Western blotting, immunohistochemistry, and confocal microscopy to determine that platelets, MEG-01 megakaryoblastic cells, and bone marrow megakaryocytes contain TFPI-2. ELISA data reveal that TFPI-2 binds factor V (FV) and partially B-domain-deleted FV (FV-1033) with K(d) ~9 nM and binds FVa with K(d) ~100 nM. Steady state analysis of surface plasmon resonance data reveal that TFPI-2 and TFPI-1 bind FV-1033 with K(d) ~36-48 nM and bind FVa with K(d) ~252-456 nM. Further, TFPI-1 (but not TFPI-1161) competes with TFPI-2 in binding to FV. These data indicate that the C-terminal basic region of TFPI-2 is similar to that of TFPI-1 and plays a role in binding to the FV B-domain acidic region. Using pull-down assays and Western blots, we show that TFPI-2 is associated with platelet FV/FVa. TFPI-2 (~7 nM) in plasma of women at the onset of labor is also, in part, associated with FV. Importantly, TFPI-2 in platelets and in plasma of pregnant women inhibits FXIa and tissue-type plasminogen activator-induced clot fibrinolysis. In conclusion, TFPI-2 in platelets from normal or pregnant subjects and in plasma from pregnant women binds FV/Va and regulates intrinsic coagulation and fibrinolysis.
Databáze: OpenAIRE
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