title: Platelet CD40 Exacerbates Atherosclerosis by Transcellular Activation of Endothelial Cells and Leukocytes.
abstract: OBJECTIVE
  Beyond their eminent role in hemostasis and thrombosis, platelets are recognized as mediators of inflammation. Platelet cluster of differentiation 40 (CD40) ligand (CD40L and CD154) plays a key role in mediating platelet-induced inflammation in atherosclerosis. CD40, the receptor for CD40L, is present on platelets; however, the role of CD40 on this cell type is until now undefined.
  
  
  RESULTS
  We found that in both mice and humans, platelet CD40 mediates the formation of platelet-leukocyte aggregates and the release of chemokine (C-X-C motif) ligand 4. Leukocytes were also less prone to adhere to CD40-deficient thrombi. However, platelet CD40 was not involved in platelet aggregation. Activated platelets isolated from Cd40(-/-)Apoe(-/-) mice adhered less to the endothelium upon injection into Apoe(-/-) mice when compared with CD40-sufficient platelets. Furthermore, lack of CD40 on injected platelets led to reduced leukocyte recruitment to the carotid artery as assayed by intravital microscopy. This was accompanied by a decrease in endothelial vascular cell adhesion molecule-1, platelet endothelial cell adhesion molecule, VE-cadherin, and P-selectin expression. To investigate the effect of platelet CD40 in atherosclerosis, Apoe(-/-) mice received thrombin-activated Apoe(-/-) or Cd40(-/-)Apoe(-/-) platelets every 5 days for 12 weeks, starting at the age of 17 weeks, when atherosclerotic plaques had already formed. When compared with mice that received Apoe(-/-) platelets, those receiving Cd40(-/-)Apoe(-/-) platelets exhibited a >2-fold reduction in atherosclerosis. Plaques of mice receiving CD40-deficient platelets were less advanced, contained less macrophages, neutrophils, and collagen, and displayed smaller lipid cores.
  
  
  CONCLUSIONS
  Platelet CD40 plays a crucial role in inflammation by stimulating leukocyte activation and recruitment and activation of endothelial cells, thereby promoting atherosclerosis.
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Norbert
authors.initials: N
authors.lastname: Gerdes
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Tom
authors.initials: T
authors.lastname: Seijkens
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Dirk
authors.initials: D
authors.lastname: Lievens
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Marijke J E
authors.initials: MJ
authors.lastname: Kuijpers
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Holger
authors.initials: H
authors.lastname: Winkels
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Delia
authors.initials: D
authors.lastname: Projahn
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Helene
authors.initials: H
authors.lastname: Hartwig
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Linda
authors.initials: L
authors.lastname: Beckers
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Remco T A
authors.initials: RT
authors.lastname: Megens
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Louis
authors.initials: L
authors.lastname: Boon
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Randolph J
authors.initials: RJ
authors.lastname: Noelle
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Oliver
authors.initials: O
authors.lastname: Soehnlein
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Johan W M
authors.initials: JW
authors.lastname: Heemskerk
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.).
authors.forename: Christian
authors.initials: C
authors.lastname: Weber
authors.affiliation: From the Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, Munich, Germany (N.G., D.L., H.W., D.P., R.T.A.M., O.S., C.W., E.L.); Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (T.S., H.H., L.B., O.S., E.L.); Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (M.J.E.K., J.W.M.H., C.W.); Bioceros BV, Utrecht, The Netherlands (L.B.); and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, NH (R.J.N.). Esther.Lutgens@med.uni-muenchen.de.
authors.forename: Esther
authors.initials: E
authors.lastname: Lutgens
mesh_terms: D000818:Animals; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics; D050197:Atherosclerosis / Q000097:blood* / Q000235:genetics / Q000473:pathology / Q000517:prevention & control; D001792:Blood Platelets / Q000378:metabolism*; D019013:CD40 Antigens / Q000097:blood* / Q000172:deficiency / Q000235:genetics; D023201:CD40 Ligand / Q000097:blood; D002478:Cells, Cultured; D002633:Chemotaxis; D018920:Coculture Techniques; D059305:Diet, High-Fat; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000097:blood* / Q000235:genetics / Q000473:pathology / Q000517:prevention & control; D007962:Leukocytes / Q000378:metabolism*; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019007:P-Selectin / Q000097:blood / Q000235:genetics; D058226:Plaque, Atherosclerotic; D010973:Platelet Adhesiveness; D010974:Platelet Aggregation; D017713:Platelet Transfusion; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D001057:Apolipoproteins E; D019013:CD40 Antigens; D019007:P-Selectin; D023201:CD40 Ligand
keywords: CD40 ligand; atherosclerosis; blood platelets; immune system; leukocytes