title: Platelets induce differentiation of human CD34+ progenitor cells into foam cells and endothelial cells.
abstract: Recruitment of human CD34+ progenitor cells toward vascular lesions and differentiation into vascular cells has been regarded as a critical initial step in atherosclerosis. Previously we found that adherent platelets represent potential mediators of progenitor cell homing besides their role in thrombus formation. On the other hand, foam cell formation represents a key process in atherosclerotic plaque formation. To investigate whether platelets are involved in progenitor cell recruitment and differentiation into endothelial cells and foam cells, we examined the interactions of platelets and CD34+ progenitor cells. Cocultivation experiments showed that human platelets recruit CD34+ progenitor cells via the specific adhesion receptors P-selectin/PSGL-1 and beta1- and beta2-integrins. Furthermore, platelets were found to induce differentiation of CD34+ progenitor cells into mature foam cells and endothelial cells. Platelet-induced foam cell generation could be prevented partially by HMG coenzyme A reductase inhibitors via reduction of matrix metalloproteinase-9 (MMP-9) secretion. Finally, agonists of peroxisome proliferator-activated receptor-alpha and -gamma attenuated platelet-induced foam cell generation and production of MMP-9. The present study describes a potentially important mechanism of platelet-induced foam cell formation and generation of endothelium in atherogenesis and atheroprogression. The understanding and modulation of these mechanisms may offer new treatment strategies for patients at high risk for atherosclerotic diseases.
authors.affiliation: Medizinische Klinik III, Eberhard Karls Universität Tübingen, Tübingen, Germany.
authors.forename: Karin
authors.initials: K
authors.lastname: Daub
authors.forename: Harald
authors.initials: H
authors.lastname: Langer
authors.forename: Peter
authors.initials: P
authors.lastname: Seizer
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Stellos
authors.forename: Andreas E
authors.initials: AE
authors.lastname: May
authors.forename: Pankaj
authors.initials: P
authors.lastname: Goyal
authors.forename: Boris
authors.initials: B
authors.lastname: Bigalke
authors.forename: Tanja
authors.initials: T
authors.lastname: Schönberger
authors.forename: Tobias
authors.initials: T
authors.lastname: Geisler
authors.forename: Dorothea
authors.initials: D
authors.lastname: Siegel-Axel
authors.forename: Robert A J
authors.initials: RA
authors.lastname: Oostendorp
authors.forename: Stephan
authors.initials: S
authors.lastname: Lindemann
authors.forename: Meinrad
authors.initials: M
authors.lastname: Gawaz
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism*; D001792:Blood Platelets / Q000378:metabolism*; D002448:Cell Adhesion; D002454:Cell Differentiation; D002478:Cells, Cultured; D018914:Cells, Immobilized; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology*; D005487:Foam Cells / Q000166:cytology / Q000502:physiology*; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D047492:Peroxisome Proliferator-Activated Receptors / Q000819:agonists; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*
chemical_list: D018952:Antigens, CD34; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D047492:Peroxisome Proliferator-Activated Receptors; D020780:Matrix Metalloproteinase 9