title: Scanning Electron Microscopy Reveals Two Distinct Classes of Erythroblastic Island Isolated from Adult Mammalian Bone Marrow.
abstract: Erythroblastic islands are multicellular clusters in which a central macrophage supports the development and maturation of red blood cell (erythroid) progenitors. These clusters play crucial roles in the pathogenesis observed in animal models of hematological disorders. The precise structure and function of erythroblastic islands is poorly understood. Here, we have combined scanning electron microscopy and immuno-gold labeling of surface proteins to develop a better understanding of the ultrastructure of these multicellular clusters. The erythroid-specific surface antigen Ter-119 and the transferrin receptor CD71 exhibited distinct patterns of protein sorting during erythroid cell maturation as detected by immuno-gold labeling. During electron microscopy analysis we observed two distinct classes of erythroblastic islands. The islands varied in size and morphology, and the number and type of erythroid cells interacting with the central macrophage. Assessment of femoral marrow isolated from a cavid rodent species (guinea pig, Cavis porcellus) and a marsupial carnivore species (fat-tailed dunnarts, Sminthopsis crassicaudata) showed that while the morphology of the central macrophage varied, two different types of erythroblastic islands were consistently identifiable. Our findings suggest that these two classes of erythroblastic islands are conserved in mammalian evolution and may play distinct roles in red blood cell production.
authors.affiliation: 1Discipline of Anatomy & Histology,School of Medical Sciences,Bosch Institute,University of Sydney,Camperdown,NSW 2050,Australia.
authors.forename: Jia Hao
authors.initials: JH
authors.lastname: Yeo
authors.affiliation: 2Discipline of Physiology,School of Medical Sciences,Bosch Institute,University of Sydney,Camperdown,NSW 2050,Australia.
authors.forename: Bronwyn M
authors.initials: BM
authors.lastname: McAllan
authors.affiliation: 1Discipline of Anatomy & Histology,School of Medical Sciences,Bosch Institute,University of Sydney,Camperdown,NSW 2050,Australia.
authors.forename: Stuart T
authors.identifier: http://orcid.org/0000-0003-3795-9461
authors.initials: ST
authors.lastname: Fraser
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D001789:Blood Group Antigens / Q000032:analysis; D001853:Bone Marrow / Q000033:anatomy & histology*; D001854:Bone Marrow Cells / Q000648:ultrastructure*; D004900:Erythroblasts / Q000648:ultrastructure*; D006168:Guinea Pigs; D008394:Marsupialia; D008565:Membrane Proteins / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D016253:Microscopy, Immunoelectron; D011990:Receptors, Transferrin / Q000032:analysis
chemical_list: D015703:Antigens, CD; D001789:Blood Group Antigens; C068126:CD71 antigen; D008565:Membrane Proteins; D011990:Receptors, Transferrin
keywords: erythroblastic islands; erythropoiesis; immuno-gold labeling; marsupials; scanning electron microscopy