Open AccessTargeting Bone Marrow Niche Macrophages: The Novel Frontier in Bone Marrow Transplant
Author(s) -
Vinchi Francesca
Publication year - 2018
Publication title -
hemasphere
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 11
ISSN - 2572-9241
DOI - 10.1097/hs9.0000000000000148
Subject(s) - microbiology and biotechnology , bone marrow , haematopoiesis , biology , macrophage , stem cell , erythropoiesis , population , immunology , erythroblast , niche , homeostasis , medicine , in vitro , genetics , ecology , environmental health , anemia
Macrophages are a heterogeneous population of cells, which macrophages is constituted by osteal macrophages or osteomacs, show a high degree of functional plasticity, derived from their ability to integrate diverse signals from the microenvironment, and acquire distinct phenotypes. Thanks to their remarkable plasticity, macrophages participate in numerous functions, including tissue regeneration, homeostasis, and inflammatory responses. In the last 10 years, significant advances have been made in the characterization of bone marrow (BM) macrophages and their contributions to bone and marrow homeostasis and health. Bone tissue and its adjacent marrow contain different subsets of tissue resident macrophages, which support the distinct niche environments and critically regulate erythropoiesis and hematopoietic cell stemness.Within the BMniche,macrophages are in direct contact with hematopoietic stem cells (HSCs) and other niche cells and exert specialized functions to maintain niche homeostasis. The first identified BM resident macrophages were the central macrophages, which behave as nurse cells for erythroblasts in a structure called erythroblastic island (EBI). The interaction of central macrophages and erythroblasts within the EBI is crucial for erythroblast survival and maturation to generate functional enucleated reticulocytes. Importantly, these macrophages promote erythroid maturation by producing trophic cytokines, providing iron for hemoglobin synthesis, and removing extruded nuclei. More recently, a novel population of resident macrophages involved in the maintenance of HSCs within the HSC niche has been described. These cells contribute to the maintenance of HSC quiescence and the control of HSC selfrenewal and proliferation. HSC-macrophage depletion leads in fact to niche alteration and HSC mobilization from BM to peripheral blood, proving the critical role of these cells in HSC retention and stemness regulation. A third subset of BM