Abstract
Although migration of hematopoietic stem cells (HSC) is essential for normal hematopoiesis and successful hematopoietic cell transplantation, little is known about the mechanisms that underlie this movement. We have sought to characterize the factors that regulate HSC migration by analyzing changes in expression of particular adhesion receptors associated with cyclophosphamide/granulocyte colony-stimulating factor (Cy/G-CSF)-induced HSC mobilization. Expression by Lineage(-/lo)Thy1.1(lo)Sca-1(+)c-kit(+) HSC of members of the beta1 integrin family of adhesion molecules was assessed in untreated or Cy/G-CSF-treated mice by multiparameter flow cytometry. In parallel, the in vivo homing properties of normal and mobilized HSC were compared following intravenous transfer of fluorescently marked HSC. Normal adult HSC express high levels of several beta1 integrin family members. Following Cy/G treatment, bone marrow HSC selectively downregulate alpha 2 integrin expression and upregulate alpha 5 expression. HSC found in the blood following Cy/G-CSF treatment express significantly lower levels of multiple integrins than their bone marrow and/or splenic counterparts. Changes in integrin expression by blood-borne HSC correlate with a 50% decrease in their ability to home to the bone marrow in short-term assays, and with previously observed defects in competitive engraftment by these HSC. Similar reductions in bone marrow (BM) homing are observed for BM HSC treated with alpha 4 integrin function blocking mAb prior to injection. Modulation of integrin expression induced by mobilization was not associated with cell-cycle progression. Changes in integrin expression and function are associated with HSC mobilization and likely significantly affect the engraftment potential of hematopoietic stem cells.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
