A novel role for PECAM-1 in megakaryocytokinesis and recovery of platelet counts in thrombocytopenic mice

Tarvinder S. Dhanjal*, Caroline Pendaries, Ewan A. Ross, Mark K. Larson, Majd B. Protty, Chris D. Buckley, Steve P. Watson

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

During thrombopoiesis, maturing megakaryocytes (MKs) migrate within the complex bone marrow stromal microenvironment from the proliferative osteoblastic niche to the capillary-rich vascular niche where proplatelet formation and platelet release occurs. This physiologic process involves proliferation, differentiation, migration, and maturation of MKs before platelet production occurs. In this study, we report a role for the glycoprotein PECAM-1 in thrombopoiesis. We show that following induced thrombocytopenia, recovery of the peripheral platelet count is impaired in PECAM-1-deficient mice. Whereas MK maturation, pro-platelet formation, and platelet production under in vitro conditions were unaffected, we identified a migration defect in PECAM-1-deficient MKs in response to a gradient of stromal cell-derived factor 1 (SDF1), a major chemokine regulating MK migration within the bone marrow. This defect could be explained by defective PECAM-1-/- MK polarization of the SDF1 receptor CXCR4 and an increase in adhesion to immobilized bone marrow matrix proteins that can be explained by an increase in integrin activation. The defect of migration and polarization was confirmed in vivo with demonstration of altered spatial localization of MKs within the bone marrow in PECAM-1-deficient mice, following immune-induced thrombocytopenia. This study identifies a novel role for PECAM-1 in regulating MK migration and thrombopoiesis.

Original languageEnglish
Pages (from-to)4237-4244
Number of pages8
JournalBlood
Volume109
Issue number10
DOIs
Publication statusPublished - 15 May 2007

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