Publications by authors named "Nils B Leimkühler"

3 Publications

  • Page 1 of 1

Heterogeneous bone-marrow stromal progenitors drive myelofibrosis via a druggable alarmin axis.

Cell Stem Cell 2021 Apr 9;28(4):637-652.e8. Epub 2020 Dec 9.

Department of Hematology, Erasmus Medical Center, Rotterdam 3015GD, the Netherlands; Department of Cell Biology, Institute for Biomedical Engineering, Faculty of Medicine, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany; Oncode Institute, Erasmus Medical Center, Rotterdam 3015GD, the Netherlands. Electronic address:

Functional contributions of individual cellular components of the bone-marrow microenvironment to myelofibrosis (MF) in patients with myeloproliferative neoplasms (MPNs) are incompletely understood. We aimed to generate a comprehensive map of the stroma in MPNs/MFs on a single-cell level in murine models and patient samples. Our analysis revealed two distinct mesenchymal stromal cell (MSC) subsets as pro-fibrotic cells. MSCs were functionally reprogrammed in a stage-dependent manner with loss of their progenitor status and initiation of differentiation in the pre-fibrotic and acquisition of a pro-fibrotic and inflammatory phenotype in the fibrotic stage. The expression of the alarmin complex S100A8/S100A9 in MSC marked disease progression toward the fibrotic phase in murine models and in patient stroma and plasma. Tasquinimod, a small-molecule inhibiting S100A8/S100A9 signaling, significantly ameliorated the MPN phenotype and fibrosis in JAK2V617F-mutated murine models, highlighting that S100A8/S100A9 is an attractive therapeutic target in MPNs.
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http://dx.doi.org/10.1016/j.stem.2020.11.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8024900PMC
April 2021

Increased CXCL4 expression in hematopoietic cells links inflammation and progression of bone marrow fibrosis in MPN.

Blood 2020 10;136(18):2051-2064

Department of Hematology, Erasmus Medical Center Cancer Institute, Rotterdam, The Netherlands.

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) that leads to progressive bone marrow (BM) fibrosis. Although the cellular mutations involved in the pathogenesis of PMF have been extensively investigated, the sequential events that drive stromal activation and fibrosis by hematopoietic-stromal cross-talk remain elusive. Using an unbiased approach and validation in patients with MPN, we determined that the differential spatial expression of the chemokine CXCL4/platelet factor-4 marks the progression of fibrosis. We show that the absence of hematopoietic CXCL4 ameliorates the MPN phenotype, reduces stromal cell activation and BM fibrosis, and decreases the activation of profibrotic pathways in megakaryocytes, inflammation in fibrosis-driving cells, and JAK/STAT activation in both megakaryocytes and stromal cells in 3 murine PMF models. Our data indicate that higher CXCL4 expression in MPN has profibrotic effects and is a mediator of the characteristic inflammation. Therefore, targeting CXCL4 might be a promising strategy to reduce inflammation in PMF.
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http://dx.doi.org/10.1182/blood.2019004095DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7678060PMC
October 2020

Inflammatory bone marrow microenvironment.

Hematology Am Soc Hematol Educ Program 2019 12;2019(1):294-302

Department of Hematology, Erasmus MC Cancer Institute, Rotterdam, The Netherlands.

Self-renewing hematopoietic stem cells and their progeny, lineage-specific downstream progenitors, maintain steady-state hematopoiesis in the bone marrow (BM). Accumulating evidence over the last few years indicates that not only primitive hematopoietic stem and progenitor cells (HSPCs), but also cells defining the microenvironment of the BM (BM niche), sense hematopoietic stress signals. They respond by directing and orchestrating hematopoiesis via not only cell-intrinsic but also cell-extrinsic mechanisms. Inflammation has many beneficial roles by activating the immune system in tissue repair and as a defense mechanism. However, chronic inflammation can have detrimental effects by stressing HSPCs, leading to cell (DNA) damage resulting in BM failure or even to leukemia. Emerging data have demonstrated that the BM microenvironment plays a significant role in the pathogenesis of hematopoietic malignancies, in particular, through disrupted inflammatory signaling, specifically in niche (microenvironmental) cells. Clonal selection in the context of microenvironmental alterations can occur in the context of toxic insults (eg, chemotherapy), not only aging but also inflammation. In this review, we summarize mechanisms that lead to an inflammatory BM microenvironment and discuss how this affects normal hematopoiesis. We pay particular attention to the process of aging, which is known to involve low-grade inflammation and is also associated with age-related clonal hematopoiesis and potentially malignant transformation.
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http://dx.doi.org/10.1182/hematology.2019000045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6913454PMC
December 2019