Lactadherin and clearance of platelet-derived microvesicles.

The transbilayer movement of phosphatidylserine from the inner to the outer leaflet of the membrane bilayer during platelet activation is associated with the release of procoagulant phosphatidylserine-rich small membrane vesicles called platelet-derived microvesicles. We tested the effect of lactadherin, which promotes the phagocytosis of phosphatidylserine-expressing lymphocytes and red blood cells, in the clearance of platelet microvesicles. Platelet-derived microvesicles were labeled with BODIPY-maleimide and incubated with THP-1-derived macrophages. The extent of phagocytosis was quantified by flow cytometry. Lactadherin promoted phagocytosis in a concentration-dependent manner with a half-maximal effect at approximately 5 ng/mL. Lactadherin-deficient mice had increased number of platelet-derived microvesicles in their plasma compared with their wild-type littermates (950 +/- 165 vs 4760 +/- 650; P = .02) and generated 2-fold more thrombin. In addition, splenic macrophages from lactadherin-deficient mice showed decreased capacity to phagocytose platelet-derived microvesicles. In an in vivo model of light/dye-induced endothelial injury/thrombosis in the cremasteric venules, lactadherin-deficient mice had significantly shorter time for occlusion compared with their wild-type littermate controls (5.93 +/- 0.43 minutes vs 9.80 +/- 1.14 minutes;P = .01). These studies show that lactadherin mediates the clearance of phosphatidylserine-expressing platelet-derived microvesicles from the circulation and that a defective clearance can induce a hypercoagulable state.

[1]  S. Nagata,et al.  Autoimmune Disease and Impaired Uptake of Apoptotic Cells in MFG-E8-Deficient Mice , 2004, Science.

[2]  C. Smith,et al.  Mouse Cremaster Venules are Predisposed to Light/Dye‐Induced Thrombosis Independent of Wall Shear Rate, CD18, ICAM‐1, or P‐Selectin , 2004, Microcirculation.

[3]  N. O. Solum,et al.  Procoagulant expression in platelets and defects leading to clinical disorders. , 1999, Arteriosclerosis, thrombosis, and vascular biology.

[4]  P. Comfurius,et al.  Scott syndrome, a bleeding disorder caused by defective scrambling of membrane phospholipids. , 2004, Biochimica et biophysica acta.

[5]  G. Grau,et al.  In vitro generation of endothelial microparticles and possible prothrombotic activity in patients with lupus anticoagulant. , 1999, The Journal of clinical investigation.

[6]  C. Benedict,et al.  Inhibition of arterial thrombosis by recombinant annexin V in a rabbit carotid artery injury model. , 1997, Circulation.

[7]  J. Rasmussen,et al.  Characterization of glycoprotein PAS-6/7 from membranes of bovine milk fat globules. , 1996, European journal of biochemistry.

[8]  S. Fedosov,et al.  Functional analyses of two cellular binding domains of bovine lactadherin. , 2000, Biochemistry.

[9]  J. Kelton,et al.  A diagnostic test for heparin‐induced thrombocytopenia: detection of platelet microparticles using flow cytometry , 1996, British journal of haematology.

[10]  T. Mayadas,et al.  The Clearance Mechanism of Chilled Blood Platelets , 2003, Cell.

[11]  Keiko Miwa,et al.  Identification of a factor that links apoptotic cells to phagocytes , 2002, Nature.

[12]  M. U. Nollert,et al.  Leukocyte-leukocyte interactions mediated by platelet microparticles under flow. , 2000, Blood.

[13]  K. Ravichandran,et al.  Engulfment of apoptotic cells: signals for a good meal , 2007, Nature Reviews Immunology.

[14]  S. Dasgupta,et al.  The role of lactadherin in the phagocytosis of phosphatidylserine-expressing sickle red blood cells by macrophages. , 2005, Haematologica.

[15]  R. Rumbaut,et al.  Differential Phototoxicity of Fluorescent Dye‐Labeled Albumin Conjugates , 1999, Microcirculation.

[16]  S. Nagata,et al.  Role of lactadherin in the clearance of phosphatidylserine‐expressing red blood cells , 2008, Transfusion.

[17]  Hong Wang,et al.  Rapid clearance of procoagulant platelet‐derived microparticles from the circulation of rabbits , 2006, Journal of thrombosis and haemostasis : JTH.

[18]  R. Pakala,et al.  Platelet microparticles promote platelet interaction with subendothelial matrix in a glycoprotein IIb/IIIa-dependent mechanism. , 1999, Circulation.

[19]  P. Wolf.  The Nature and Significance of Platelet Products in Human Plasma , 1967, British journal of haematology.

[20]  A. Schroit,et al.  Pathophysiologic implications of membrane phospholipid asymmetry in blood cells. , 1997, Blood.

[21]  C. W. Heegaard,et al.  Lactadherin detects early phosphatidylserine exposure on immortalized leukemia cells undergoing programmed cell death , 2006, Cytometry. Part A : the journal of the International Society for Analytical Cytology.

[22]  P. Comfurius,et al.  Regulatory Mechanisms in Maintenance and Modulation of Transmembrane Lipid Asymmetry: Pathophysiological Implications , 1996, Lupus.

[23]  J. Kelton,et al.  Calpain activity in patients with thrombotic thrombocytopenic purpura is associated with platelet microparticles. , 1992, Blood.

[24]  S. Dasgupta,et al.  Lactadherin binding and phosphatidylserine expression on cell surface-comparison with annexin A5. , 2006, Translational research : the journal of laboratory and clinical medicine.

[25]  G. E. Gilbert,et al.  Lactadherin inhibits enzyme complexes of blood coagulation by competing for phospholipid-binding sites. , 2003, Blood.

[26]  José A López,et al.  Lactadherin mediates sickle cell adhesion to vascular endothelial cells in flowing blood , 2007, Haematologica.

[27]  P. Comfurius,et al.  Surface exposure of phosphatidylserine in pathological cells , 2005, Cellular and Molecular Life Sciences CMLS.

[28]  R. Birge,et al.  The opsonin MFG-E8 is a ligand for the αvβ5 integrin and triggers DOCK180-dependent Rac1 activation for the phagocytosis of apoptotic cells , 2004 .

[29]  S. Nagata,et al.  Masking of Phosphatidylserine Inhibits Apoptotic Cell Engulfment and Induces Autoantibody Production in Mice , 2004, The Journal of experimental medicine.

[30]  A. Hafezi-Moghadam,et al.  Interaction of P-selectin and PSGL-1 generates microparticles that correct hemostasis in a mouse model of hemophilia A , 2003, Nature Medicine.

[31]  V. Novakovic,et al.  Crystal Structure of Lactadherin C2 Domain at 1.7Å Resolution with Mutational and Computational Analyses of Its Membrane-binding Motif* , 2008, Journal of Biological Chemistry.

[32]  H. Coenraad Hemker,et al.  Calibrated Automated Thrombin Generation Measurement in Clotting Plasma , 2003, Pathophysiology of Haemostasis and Thrombosis.

[33]  C. W. Heegaard,et al.  Lactadherin blocks thrombosis and hemostasis in vivo: correlation with platelet phosphatidylserine exposure , 2008, Journal of thrombosis and haemostasis : JTH.

[34]  V. Fadok,et al.  Phagocyte receptors for apoptotic cells: recognition, uptake, and consequences. , 2001, The Journal of clinical investigation.

[35]  M. Ratajczak,et al.  Platelet- and megakaryocyte-derived microparticles transfer CXCR4 receptor to CXCR4-null cells and make them susceptible to infection by X4-HIV , 2003, AIDS.

[36]  D. Praticò,et al.  Platelet-derived microparticles stimulate proliferation, survival, adhesion, and chemotaxis of hematopoietic cells. , 2002, Experimental hematology.

[37]  A. Schroit,et al.  Loss of membrane phospholipid asymmetry in platelets and red cells may be associated with calcium-induced shedding of plasma membrane and inhibition of aminophospholipid translocase. , 1990, Biochimica et biophysica acta.

[38]  J. Takagi,et al.  Milk fat globule EGF factor 8 in the serum of human patients of systemic lupus erythematosus , 2008, Journal of leukocyte biology.

[39]  G. Dale,et al.  Quantitation of microparticles released from coated‐platelets , 2005, Journal of thrombosis and haemostasis : JTH.

[40]  A. Yalçin,et al.  A monoclonal antibody to human platelet glycoprotein IIIa detects a related protein in cultured human endothelial cells. , 1985, The Journal of clinical investigation.

[41]  R. Bertina,et al.  Microparticle-Associated Tissue Factor Activity: A Link between Cancer and Thrombosis?. , 2005 .

[42]  R. Birge,et al.  The opsonin MFG-E8 is a ligand for the alphavbeta5 integrin and triggers DOCK180-dependent Rac1 activation for the phagocytosis of apoptotic cells. , 2004, Experimental cell research.

[43]  C. Esmon,et al.  Assembly of the platelet prothrombinase complex is linked to vesiculation of the platelet plasma membrane. Studies in Scott syndrome: an isolated defect in platelet procoagulant activity. , 1989, The Journal of biological chemistry.