Summary We document here that intensive care COVID-19 patients suffer a profound decline in hemoglobin levels but show an increase of circulating nucleated red cells, suggesting SARS-CoV-2 infection either directly or indirectly induces stress erythropoiesis. ACE2 expression peaks during erythropoiesis and renders erythroid progenitors vulnerable to by SARS-CoV-2. Early progenitors, de...

PU.1 is a hematopoietic-specific transcriptional activator that is absolutely required for the differentiation of B lymphocytes and myeloid-lineage cells. Although PU.1 is also expressed by early erythroid progenitor cells, its role in erythropoiesis, if any, is unknown. To investigate the relevance of PU.1 in erythropoiesis, we produced a line of PU.1-deficient mice carrying a green fluorescen...

Anemia seen in patients with chronic kidney disease is a particular form of 'anemia of chronic disease'. Although multifactorial in origin, erythropoiesis-stimulating agents (ESAs) and adjuvant iron therapy represent the primary treatment for anemia in chronic kidney disease. Subsequent clinical observations revealed that these ESA hyporesponsive patients often had increased systemic inflammati...

Serum erythropoietin level less than 100U/L and a transfusion requirement of less than 2 units per month are the best predictive factors for response to treatment by erythropoiesis-stimulating agents in low/int-1 myelodysplastic syndromes. To investigate the factors influencing the response to erythropoiesis-stimulating agents, we enrolled 127 low/int-1 myelodysplastic syndrome patients at diag...

BACKGROUND We and others have shown previously that over-expression of hepcidin antimicrobial peptide, independently of inflammation, induces several features of anemia of inflammation and chronic disease, including hypoferremia, sequestration of iron stores and iron-restricted erythropoiesis. Because the iron-restricted erythropoiesis evident in hepcidin transgenic mice differs from the normoc...

Myelodysplastic syndromes (MDS) are a group of age-related clonal hematologic diseases characterized by anemia, neutropenia, and thromobocytopenia. The mechanisms of anemia in MDS are unclear, which is due to the heterogeneity of MDS involving many cytogenetic and molecular abnormalities. Using a mouse genetic approach, here we show that dual deficiency of mDia1 and miR-146a, two genes located ...

Erythrocytes are responsible for transporting oxygen to tissue and are essential for the survival of almost all vertebrate animals. Circulating erythrocyte counts are tightly regulated and respond to erythrocyte mass and oxygen tension. Since the discovery of erythropoietin, the erythropoietic responses to environment and tissue oxygen tension have been investigated in mice and human. Moreover,...

Regulation of the cell cycle is intimately linked to erythroid differentiation, yet how these processes are coupled is not well understood. To gain insight into this coordinate regulation, we examined the role that the retinoblastoma protein (Rb), a central regulator of the cell cycle, plays in erythropoiesis. We found that Rb serves a cell-intrinsic role and its absence causes ineffective eryt...

The importance of inadequate haemoglobin synthesis and ineffective erythropoiesis in the anaemia of rheumatoid arthritis was studied by measuring the incorporation of 15N glycine into haemoglobin haem and early labelled bilirubin in a patient with severe anaemia before and after response to gold therapy. Initially, total erythroid haem turnover was decreased but haem turnover due to ineffective...

The Tal1 transcription factor is essential for the development of the hematopoietic system and plays a role during definitive erythropoiesis in the adult. Despite the importance of Tal1 in erythropoiesis, only a small number of erythroid differentiation target genes are known. A chromatin precipitation and cloning approach was established to uncover novel Tal1 target genes in erythropoiesis. Th...