Departamento de Microbiología y Ecología, Universitat de València, Burjassot, Spain
Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Burjassot, Spain
Departamento de Patología, Universitat de València, Valencia, Spain
Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
Correspondence: M. Luisa Gil, Universitat de València, Facultad de Ciencias Biológicas, Departamento de Microbiología y Ecología, Edificio de Investigación, C/ Dr. Moliner, 50, 46100 Burjassot (Valencia), Spain.
- Mots-clés : hematopoietic stem and progenitor cells, macrophages, M-CSF, GM-CSF, TLRs, Candida albicans
- DOI : 10.1684/ecn.2017.0398
- Page(s) : 102-10
- Année de parution : 2017
Toll-like receptor (TLR) agonists drive hematopoietic stem and progenitor cells (HSPCs) to differentiate along the myeloid lineage in vitro and also in vivo following infection. In this study, we used an in vitro model of HSPC differentiation to investigate the functional consequences (cytokine production) that exposing HSPCs to various pathogen-associated molecular patterns (PAMPs) and Candida albicans cells have on the subsequently derived macrophages. Mouse HSPCs (Lin– cells) were cultured with GM-CSF to induce macrophage differentiation in the presence or absence of the following pattern recognition receptor (PRR) agonists: Pam3CSK4 (TLR2 ligand), LPS (TLR4 ligand), depleted zymosan (which only activates Dectin-1), or inactivated C. albicans yeasts (which activate several PRRs, mainly TLR2 and Dectin-1). Our data show that only pure TLR2 ligand exposure (transient and continuous) impacts the inflammatory function of GM-CSF-derived macrophages, because Pam3CSK4-exposed HSPCs generate macrophages with a diminished ability to produce inflammatory cytokines. Interestingly, the Pam3CSK4-induced tolerance of macrophages (by transient exposure of HSPCs) is reinforced by subsequent exposure to C. albicans cells in GM-CSF-derived macrophages; however, the induced tolerance is partially reversed in M-CSF-derived macrophages. Therefore, the ability of macrophages to produce inflammatory cytokines is extremely dependent on how the HSPCs from which they are derived receive and integrate multiple microenvironmental signals (PRR ligands and/or CSFs).