Targeting VLA4 integrin and CXCR2 mobilizes serially repopulating hematopoietic stem cells
Darja Karpova, … , Daniel C. Link, John F. DiPersio
Darja Karpova, … , Daniel C. Link, John F. DiPersio
Published May 14, 2019
Citation Information: J Clin Invest. 2019;129(7):2745-2759. https://doi.org/10.1172/JCI124738.
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Research Article

Targeting VLA4 integrin and CXCR2 mobilizes serially repopulating hematopoietic stem cells

Abstract

Mobilized peripheral blood has become the primary source of hematopoietic stem and progenitor cells (HSPCs) for stem cell transplantation, with a 5-day course of granulocyte colony-stimulating factor (G-CSF) as the most common regimen used for HSPC mobilization. The CXCR4 inhibitor plerixafor is a more rapid mobilizer, yet not potent enough when used as a single agent, thus emphasizing the need for faster acting agents with more predictable mobilization responses and fewer side effects. We sought to improve hematopoietic stem cell transplantation by developing a new mobilization strategy in mice through combined targeting of the chemokine receptor CXCR2 and the very late antigen 4 (VLA4) integrin. Rapid and synergistic mobilization of HSPCs along with an enhanced recruitment of true HSCs was achieved when a CXCR2 agonist was coadministered in conjunction with a VLA4 inhibitor. Mechanistic studies revealed involvement of CXCR2 expressed on BM stroma in addition to stimulation of the receptor on granulocytes in the regulation of HSPC localization and egress. Given the rapid kinetics and potency of HSPC mobilization achieved by the VLA4 inhibitor and CXCR2 agonist combination in mice compared with currently approved HSPC mobilization methods, the combination represents an exciting potential strategy for clinical development in the future.

Authors

Darja Karpova, Michael P. Rettig, Julie Ritchey, Daniel Cancilla, Stephanie Christ, Leah Gehrs, Ezhilarasi Chendamarai, Moses O. Evbuomwan, Matthew Holt, Jingzhu Zhang, Grazia Abou-Ezzi, Hamza Celik, Eliza Wiercinska, Wei Yang, Feng Gao, Linda G. Eissenberg, Richard F. Heier, Stacy D. Arnett, Marvin J. Meyers, Michael J. Prinsen, David W. Griggs, Andreas Trumpp, Peter G. Ruminski, Dwight M. Morrow, Halvard B. Bonig, Daniel C. Link, John F. DiPersio

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Figure 3

Granulocytes are indispensable for tGro-induced mobilization.

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Granulocytes are indispensable for tGro-induced mobilization. (A) Effect...
(A) Effect of different sequences of injection. Two groups of BALB/cJ mice received pretreatment with PBS or tGro-β (2.5 mg/kg, s.c.) 15 minutes prior to the injection of CWHM-823 (3 mg/kg, s.c.). Accordingly, 2 other groups were pretreated with PBS or the VLA4 antagonist (3 mg/kg CWHM-823, s.c.) 45 minutes prior to tGro-β (2.5 mg/kg, s.c.) injection. A fifth group received a simultaneous injection of CWHM-823 plus tGro-β at the indicated doses. At 15 and 60 minutes after the administration of the second compound (or the simultaneous injection in the control group), circulating CFU-C numbers were measured. Each bar is mean ± SEM, n = 4–5. ***P < 0.001, **P < 0.01, *P < 0.05. (B–D) For transient depletion of blood neutrophils, mice were pretreated with an anti-Gr1 antibody in vivo (200 μg/mouse, i.v.) 36 hours prior to mobilization with tGro-β (2.5 mg/kg, s.c., time point 15 minutes), CWHM-823 (3.0 mg/kg, s.c., time point 60 minutes), or the combined agents (doses same as for separate treatments, time point 30 minutes). Nonmobilized mice were used as controls (baseline). Moreover, all 4 conditions were analyzed in cohorts that had been pretreated with a control antibody (200 μg/mouse, i.v.). (B) Representative scatter plot analyses of unmobilized blood using flow cytometry, with granulocytes virtually absent in anti-Gr1–treated mice. (C–D) Numbers of circulating neutrophils (C) and CFU-Cs (D). Each bar is mean ± SEM, n = 7–9. ***P < 0.001, **P < 0.01. Statistical comparisons were made using ANOVA, followed by step-down Bonferroni’s adjustment for multiple comparisons. Logarithm transformation was performed for the data in C and D.