On the expulsion of the erythroid nucleus and its phagocytosis

Skutelsky, Ehud; Danon, D.

doi:10.1002/ar.1091730111

Cited by 35 publications

(16 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Studies in the 1960s 33,34 and later document that at conclusion of terminal differentiation extruded erythroblast nuclei undergo phagocytosis by central macrophages. One intriguing question is how expelled nuclei remain localized at the macrophage surface after extrusion.…”

Section: Role Of Central Macrophagesmentioning

confidence: 99%

Erythroblastic islands: niches for erythropoiesis

Chasis

Mohandas

2008

Blood

438

420

View full text Add to dashboard Cite

Erythroblastic islands, the specialized niches in which erythroid precursors proliferate, differentiate, and enucleate, were first described 50 years ago by analysis of transmission electron micrographs of bone marrow. These hematopoietic subcompartments are composed of erythroblasts surrounding a central macrophage. A hiatus of several decades followed, during which the importance of erythroblastic islands remained unrecognized as erythroid progenitors were shown to possess an autonomous differentiation program with a capacity to complete terminal differentiation in vitro in the presence of erythropoietin but without macrophages. However, as the extent of proliferation, differentiation, and enucleation efficiency documented in vivo could not be recapitulated in vitro, a resurgence of interest in erythroid niches has emerged. We now have an increased molecular understanding of processes operating within erythroid niches, including cell-cell and cellextracellular matrix adhesion, positive and negative regulatory feedback, and central macrophage function. These features of erythroblast islands represent important contributors to normal erythroid development, as well as altered erythropoiesis found in such diverse diseases as anemia of inflammation and chronic disease, myelodysplasia, thalassemia, and malarial anemia. Coupling of historical, current, and future insights will be essential to understand the tightly regulated production of red cells both in steady state and stress erythropoiesis. DiscoveryThere is a great deal of recent excitement concerning stem cell niches that regulate self-renewal and cell differentiation in the bone marrow, but it should be noted that the first description of a hematopoietic niche actually took place 50 years ago when the French hematologist, Marcel Bessis, discovered erythroblastic islands. 1 Cell-cell and cell-extracellular matrix interactions that are the hallmark of niches are increasingly being recognized as sites of both positive and negative regulators of cell proliferation and differentiation in many tissue types. As such, features of erythroid niches represent important contributors to normal erythroid development, as well as altered erythropoiesis found in such diverse diseases as thalassemia with its ineffective erythropoiesis, myelodysplasia (MDS) accompanied by disordered erythroid maturation, and anemia of inflammation and chronic disease secondary to perturbed iron metabolism.Bessis originally characterized the erythroblastic island as developing erythroblasts surrounding a central macrophage, based on careful analysis of transmission electron micrographs of sections of bone marrow (Figure 1). Erythroid islands are also present in fetal liver and spleen. 1 It is important to note that these islands are not seen in bone marrow aspirates because they are readily disrupted during smear preparation. Based on structural observations, Bessis and colleagues made a number of interesting inferences concerning the role of central macrophages. It was suggested that the macro...

show abstract

Section: Role Of Central Macrophagesmentioning

confidence: 99%

Erythroblastic islands: niches for erythropoiesis

Chasis

Mohandas

2008

Blood

438

420

View full text Add to dashboard Cite

show abstract

“…It has long been recognized that they phagocytose extruded erythroblast nuclei at the conclusion of terminal differentiation [42,43,44]. In the fetal liver expelled nuclei rapidly Macrophages also secrete cytokines, including burst-promoting activity and insulin-like growth factor-1 (IGF-1), that stimulate growth of both burst forming unit-erythroid (BFU-E) and colony forming unit -erythroid (CFU-E) [48,49,50].…”

Section: Central Macrophage Functionmentioning

confidence: 99%

Erythroblastic islands: specialized microenvironmental niches for erythropoiesis

Chasis

2006

Current Opinion in Hematology

View full text Add to dashboard Cite

1 ABSTRACT Purpose of reviewErythroblasts differentiate within specialized niches, termed erythroblastic islands, composed of erythroblasts surrounding a central macrophage. This review focuses on our current understanding of molecular mechanisms operating within islands including cell-cell adhesion, regulatory feedback and central macrophage function. Recent findingsErythroblasts express a variety of adhesion molecules and recently two interactions have been identified which appear to be critical for island integrity. Erythroblast macrophage protein 2 ABSTRACT (CONTINUED) SummaryAlthough our understanding of molecular mechanisms operating within islands is at an early stage, tantalizing evidence suggests that erythroblastic islands are specialized niches where intercellular interactions in concert with cytokines play critical roles in regulating erythropoiesis.

show abstract

“…These "nursing" macrophages at the center of erythropoietic islands have also been proposed to secrete cytokines essential to erythroblast survival and maintenance such as insulin-like growth factor 1 [7,8]. Finally erythroid island macrophages phagocytose and degrade erythroblast nuclei during nuclear extrusion, a step necessary to generate anucleated reticulocytes [9,10].…”

Section: Introductionmentioning

confidence: 99%