OBJECTIVE: Peripheral blood platelet-derived microparticles (PMPs) circulate in blood and may interact directly with target cells affecting their various biological functions. METHODS: To investigate the effect of human PMPs on hematopoiesis, we first phenotyped them for expression of various surface molecules and subsequently studied various biological responses of normal stem/progenitor (CD34(+)) and more differentiated precursor cells as well as several leukemic cell lines to PMPs. RESULTS: We found that, in addition to platelet-endothelium attachment receptors (CD41, CD61 and CD62), PMPs express G-protein-coupled seven transmembrane-span receptors such as CXCR4 and PAR-1; cytokine receptors including TNF-RI, TNF-RII, and CD95; and ligands such as CD40L and PF-4. Moreover, we found that several of these receptors could be transferred by PMPs to the membranes of normal as well as malignant cells and observed that PMPs: 1) chemoattract these cells, 2) increase their adhesion, proliferation, and survival, and 3) activate in these cells various intracellular signaling cascades including MAPK p42/44, PI-3K-AKT, and STAT proteins. The biological effects of PMPs were only partly reduced by heat inactivation or trypsin digest, indicating that, in addition to the protein components of PMPs, lipid components are also responsible for their biological activity. CONCLUSIONS: We conclude that PMPs modulate biological functions of hematopoietic cells and postulate that they play an important but as yet not fully understood role in intercellular cross-talk in hematopoiesis. Further studies, however, are needed to identify the PMP components that exert specific biological effects.
OBJECTIVE: Peripheral blood platelet-derived microparticles (PMPs) circulate in blood and may interact directly with target cells affecting their various biological functions. METHODS: To investigate the effect of human PMPs on hematopoiesis, we first phenotyped them for expression of various surface molecules and subsequently studied various biological responses of normal stem/progenitor (CD34(+)) and more differentiated precursor cells as well as several leukemic cell lines to PMPs. RESULTS: We found that, in addition to platelet-endothelium attachment receptors (CD41, CD61 and CD62), PMPs express G-protein-coupled seven transmembrane-span receptors such as CXCR4 and PAR-1; cytokine receptors including TNF-RI, TNF-RII, and CD95; and ligands such as CD40L and PF-4. Moreover, we found that several of these receptors could be transferred by PMPs to the membranes of normal as well as malignant cells and observed that PMPs: 1) chemoattract these cells, 2) increase their adhesion, proliferation, and survival, and 3) activate in these cells various intracellular signaling cascades including MAPK p42/44, PI-3K-AKT, and STAT proteins. The biological effects of PMPs were only partly reduced by heat inactivation or trypsin digest, indicating that, in addition to the protein components of PMPs, lipid components are also responsible for their biological activity. CONCLUSIONS: We conclude that PMPs modulate biological functions of hematopoietic cells and postulate that they play an important but as yet not fully understood role in intercellular cross-talk in hematopoiesis. Further studies, however, are needed to identify the PMP components that exert specific biological effects.
Authors: Daniel L Sprague; Bennett D Elzey; Scott A Crist; Thomas J Waldschmidt; Robert J Jensen; Timothy L Ratliff Journal: Blood Date: 2008-01-15 Impact factor: 22.113
Authors: Magda Kucia; Kacper Jankowski; Ryan Reca; Marcin Wysoczynski; Laura Bandura; Daniel J Allendorf; Jin Zhang; Janina Ratajczak; Mariusz Z Ratajczak Journal: J Mol Histol Date: 2004-03 Impact factor: 2.611
Authors: Roberto Cangemi; Andrea Celestini; Maria Del Ben; Pasquale Pignatelli; Roberto Carnevale; Marco Proietti; Cinzia Myriam Calabrese; Stefania Basili; Francesco Violi Journal: Intern Emerg Med Date: 2012-07-28 Impact factor: 3.397