Advances in understanding the mechanisms of erythropoiesis in homeostasis and disease.

Anaemia or decreased blood haemoglobin is the most common blood disorder often characterized by reduced red blood cell (RBC) numbers. RBCs are produced from differentiation and commitment of haematopoietic stem cells to the erythroid lineage by a process called erythropoiesis. Coordination of erythropoietin receptor signalling with several erythroid transcription factors including GATA1 is essential for this process. A number of additional players that are critical for RBC production have been identified in recent years. Major technological advances, such as the development of RNA interference, genetically modified animals, including zebrafish, and imaging flow cytometry have led to these discoveries; the emergence of -omics approaches in combination with the optimization of ex vivo erythroid cultures have also produced a more comprehensive understanding of erythropoiesis. Here we summarize studies describing novel regulators of erythropoiesis that modulate erythroid cell production in the context of human erythroid disorders involving hypoxia, iron regulation, immune-related molecules, and the transcription factor FOXO3.