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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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 5

CXCL8 is one of the main cytokines released by CMML patient iGRANs.

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CXCL8 is one of the main cytokines released by CMML patient iGRANs. (A a...
(A and B) Bulk RNA-Seq of sorted iGRAN collected from healthy donors (CTL) and CMML patients. Gene-concept network representation of enriched genes of 4 pathways (chemokine activity, chemokine receptor binding, cytokine activity, cytokine receptor binding). Dot color, log2foldchange. Size of beige central dots, number of core enriched genes (A). CXCL8 mRNA expression (normalized counts) in control cells (n = 7) and CMML iGRAN (n =10) (B). Mann-Whitney U test. (C) CXCL8 mRNA expression assessed by RT-qPCR in healthy donor and CMML; left panels, samples used for RNA-Seq; right panel, independent cohort of iGRANs collected from 17 control and 18 CMML. Ct values normalized to GAPDH, RPL32, and GUS genes. Mann-Whitney U test. (D) Volcano plot of cytokine and chemokine levels (n = 44) measured in circulating plasma of 23 iGRAN-low compared with 26 iGRAN-high CMML (threshold ≥14%, iGRAN fraction in box plot for each group on the left panel). (E) Indicated proteins were quantified in the supernatant of iGRANs (S), using culture medium (M) as a control. Mann-Whitney U test. (F) Intracellular cytokine production by B/NK cells, T cells, monocytes, iGRAN, and neutrophils (PMN) in fresh PB samples collected from CMML patients. Left panels, fraction of cells expressing the studied cytokine; right panels, median fluorescence intensity for CXCL8 (n = 12), IL-16 (n = 12), or MCP2 (n = 9) in cells expressing the cytokine. One-way ANOVA, Tukey’s multiple comparison. (G) CXCL8 mRNA expression (RT-qPCR) in iGRAN of 17 healthy donors and 32 CMML, according to WT and mutated (Mut) status of indicated genes. Mann-Whitney U test. (H) Spearman’s correlation between CXCL8 normalized expression and gene set variation analysis (GSVA) score for the hallmark “TNFA_SIGNALING_VIA_NFKB”. Each dot represents iGRAN sample from TET2-mutated patients (n = 8), TET2-WT patients (n = 2), and controls (n = 7). (I) CXCL8 mRNA expression after 24 hours of iGRAN culture with 0.5 μM Bay 11-7082, normalized to RPL32, HPRT, and PPIA genes. Fold change compared with DMSO-treated iGRANs. Paired t test. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.