CXCL8 secreted by immature granulocytes inhibits WT hematopoiesis in chronic myelomonocytic leukemia
Paul Deschamps, … , Eric Solary, Dorothée Selimoglu-Buet
Paul Deschamps, … , Eric Solary, Dorothée Selimoglu-Buet
Published November 15, 2024
Citation Information: J Clin Invest. 2024;134(22):e180738. https://doi.org/10.1172/JCI180738.
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Research Article Hematology

CXCL8 secreted by immature granulocytes inhibits WT hematopoiesis in chronic myelomonocytic leukemia

Abstract

Chronic myelomonocytic leukemia (CMML) is a severe myeloid malignancy with limited therapeutic options. Single-cell analysis of clonal architecture demonstrates early clonal dominance with few residual WT hematopoietic stem cells. Circulating myeloid cells of the leukemic clone and the cytokines they produce generate a deleterious inflammatory climate. Our hypothesis is that therapeutic control of the inflammatory component in CMML could contribute to stepping down disease progression. The present study explored the contribution of immature granulocytes (iGRANs) to CMML progression. iGRANs were detected and quantified in the peripheral blood of patients by spectral and conventional flow cytometry. Their accumulation was a potent and independent poor prognostic factor. These cells belong to the leukemic clone and behaved as myeloid-derived suppressor cells. Bulk and single-cell RNA-Seq revealed a proinflammatory status of iGRAN that secreted multiple cytokines of which CXCL8 was at the highest level. This cytokine inhibited the proliferation of WT but not CMML hematopoietic stem and progenitor cells (HSPCs) in which CXCL8 receptors were downregulated. CXCL8 receptor inhibitors and CXCL8 blockade restored WT HSPC proliferation, suggesting that relieving CXCL8 selective pressure on WT HSPCs is a potential strategy to slow CMML progression and restore some healthy hematopoiesis.

Authors

Paul Deschamps, Margaux Wacheux, Axel Gosseye, Margot Morabito, Arnaud Pagès, Anne-Marie Lyne, Alexia Alfaro, Philippe Rameau, Aygun Imanci, Rabie Chelbi, Valentine Marchand, Aline Renneville, Mrinal M. Patnaik, Valerie Lapierre, Bouchra Badaoui, Orianne Wagner-Ballon, Céline Berthon, Thorsten Braun, Christophe Willekens, Raphael Itzykson, Pierre Fenaux, Sylvain Thépot, Gabriel Etienne, Emilie Elvira-Matelot, Francoise Porteu, Nathalie Droin, Leïla Perié, Lucie Laplane, Eric Solary, Dorothée Selimoglu-Buet

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Figure 3

iGRANs demonstrate features of myeloid-derived suppressive cells.

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iGRANs demonstrate features of myeloid-derived suppressive cells. (A) Re...
(A) Representative conventional flow plots showing cell-surface expression of indicated markers among low-density peripheral blood cells (PBMC), separating iGRANs from monocytes, residual PMN, and lymphocytes, according to the gating strategy shown in Supplemental Figure 2. (B) Single-cell analysis of PBMCs collected from 2 CMML patients with a fraction of 14% or more and 2 with a lower iGRAN fraction; unsupervised clustering of pooled data separating 15 cluster groups in indicated cell categories. Ery, erythroid cells; My, myeloid cells; MK, megakaryocytes; Gran, granulocytes. (C) Dot plot showing the average expression (color scaled) of selected granulocyte genes and the percentage of cells that expressed those genes in indicated granulocytic clusters. (D) UMAP representation of each patient sample, 2 iGRAN-low (<14%) and 2 iGRAN-high (≥14%) CMML patients. (E) Fraction of each cell type in ITGAM+ clusters corresponding to CD11b+CD33+ cells per CMML patient. Colors are cluster codes defined in B. (F) Expression of indicated genes in enriched fraction of iGRANs, monocytes, and neutrophils measured by RT-qPCR and normalized to RPL32, GUS, and GAPDH housekeeping genes (n = 8 CMML patients). Kruskal-Wallis test. (G) Suppressive activity of iGRANs on T cell proliferation. iGRAN-low (<14%, n = 6, left panels) and iGRAN-high (≥14%, n = 6, right panels) PBMCs were labeled with Cell Trace Violet before activating T cells with anti-CD3 and anti-CD28 antibodies; CD4 (upper panels) and CD8 (lower panels) T cell proliferation was measured at day 4 by flow cytometry. We used PBMCs without any manipulation, PBMCs in which iGRAN have been depleted (iGRAN-dep PBMC), and iGRAN-dep PBMCs with addition of 10% sorted iGRANs. T cell proliferation (%) is relative to the highest proliferation, observed with iGRAN-dep PBMCs. One-way ANOVA, Tukey’s multiple comparison. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.