Differentiating erythroblasts adapt to mechanical stimulation by upregulation of cholesterol biosynthesis via S1P/SREBP-induced HMGCR expression.

Understanding how mechanical stress affects erythropoiesis is crucial to produce transfusable erythrocytes in fluid-turbulent bioreactors. We investigated the effects of shear-stress on differentiating CD49dCD235a primary human erythroblasts (EBL) at molecular, cellular, and functional level. Shear-stress, at differentiation onset, enhanced EBL maturation and induced upregulation of genes regulating cholesterol/lipids biosynthesis, causing changes in cell lipid composition.

A cellular reporter system to evaluate endogenous fetal hemoglobin induction and screen for therapeutic compounds.

Reactivation of fetal hemoglobin expression alleviates the symptoms associated with β-globinopathies, severe hereditary diseases with significant global health implications due to their high morbidity and mortality rates. The symptoms emerge following the postnatal transition from fetal-to-adult hemoglobin expression. Extensive research has focused on inducing the expression of the fetal γ-globin subunit to reverse this switch and ameliorate these symptoms.

LSD1/KDM1A and GFI1B repress endothelial fate and induce hematopoietic fate in induced pluripotent stem cell-derived hemogenic endothelium.

Differentiation of induced pluripotent stem cells (iPSC) into hematopoietic lineages offers great therapeutic potential. During embryogenesis, hemogenic endothelium (HE) gives rise to hematopoietic stem and progenitor cells through the endothelial- to-hematopoietic transition (EHT). Understanding this process using iPSC is key to generating functional hematopoietic stem cells (HSC), a currently unmet challenge.

The Gárdos Channel and Piezo1 Revisited: Comparison between Reticulocytes and Mature Red Blood Cells.

The Gárdos channel (KCNN4) and Piezo1 are the best-known ion channels in the red blood cell (RBC) membrane. Nevertheless, the quantitative electrophysiological behavior of RBCs and its heterogeneity are still not completely understood. Here, we use state-of-the-art biochemical methods to probe for the abundance of the channels in RBCs.

E-cadherin/β-catenin expression is conserved in human and rat erythropoiesis and marks stress erythropoiesis.

E-cadherin is a crucial regulator of epithelial cell-to-cell adhesion and an established tumor suppressor. Aside epithelia, E-cadherin expression marks the erythroid cell lineage during human but not mouse hematopoiesis. However, the role of E-cadherin in human erythropoiesis remains unknown.

Iron-loaded deferiprone can support full hemoglobinization of cultured red blood cells.

Iron, supplemented as iron-loaded transferrin (holotransferrin), is an essential nutrient in mammalian cell cultures, particularly for erythroid cultures. The high cost of human transferrin represents a challenge for large scale production of red blood cells (RBCs) and for cell therapies in general. We evaluated the use of deferiprone, a cell membrane-permeable drug for iron chelation therapy, as an iron carrier for erythroid cultures.

E-Cadherin Expression Distinguishes Mouse from Human Hematopoiesis in the Basophil and Erythroid Lineages.

E-cadherin is a key regulator of epithelial cell-cell adhesion, the loss of which accelerates tumor growth and invasion. E-cadherin is also expressed in hematopoietic cells as well as epithelia. The function of hematopoietic E-cadherin is, however, mostly elusive.

Expansion and differentiation of ex vivo cultured erythroblasts in scalable stirred bioreactors.

Transfusion of donor-derived red blood cells (RBCs) is the most common form of cell therapy. Production of transfusion-ready cultured RBCs (cRBCs) is a promising replacement for the current, fully donor-dependent therapy. A single transfusion unit, however, contains 2 × 10 RBC, which requires large scale production.

The Function of Ion Channels and Membrane Potential in Red Blood Cells: Toward a Systematic Analysis of the Erythroid Channelome.

Erythrocytes represent at least 60% of all cells in the human body. During circulation, they experience a huge variety of physical and chemical stimulations, such as pressure, shear stress, hormones or osmolarity changes. These signals are translated into cellular responses through ion channels that modulate erythrocyte function.

Epigenomic analysis of KLF1 haploinsufficiency in primary human erythroblasts.

Haploinsufficiency for the erythroid-specific transcription factor KLF1 is associated with hereditary persistence of fetal hemoglobin (HPFH). Increased HbF ameliorates the symptoms of β-hemoglobinopathies and downregulation of KLF1 activity has been proposed as a potential therapeutic strategy. However, the feasibility of this approach has been challenged by the observation that KLF1 haploinsufficient individuals with the same KLF1 variant, within the same family, display a wide range of HbF levels.

Circular RNAs exhibit limited evidence for translation, or translation regulation of the mRNA counterpart in terminal hematopoiesis.

Each day, about 10 erythrocytes and platelets are released into the bloodstream. This substantial output from hematopoietic stem cells is tightly regulated by transcriptional and epigenetic factors. Whether and how circular RNAs (circRNAs) contribute to the differentiation and/or identity of hematopoietic cells is to date not known.

Novel variants in Krueppel like factor 1 that cause persistence of fetal hemoglobin in In(Lu) individuals.

Beta-hemoglobinopathies become prominent after birth due to a switch from γ-globin to the mutated β-globin. Haploinsufficiency for the erythroid specific indispensable transcription factor Krueppel-like factor 1 (KLF1) is associated with high persistence of fetal hemoglobin (HPFH). The In(Lu) phenotype, characterized by low to undetectable Lutheran blood group expression is caused by mutations within KLF1 gene.

Generation and characterization of a human iPSC line SANi006-A from a Gray Platelet Syndrome patient.

Induced pluripotent stem cells (iPSCs) were generated from erythroblasts (EBLs) obtained from a patient diagnosed with Gray Platelet Syndrome (GPS), caused by compound heterozygous NBEAL2 mutations (c.6568delT and c.7937T>C).

Generation and characterization of a human iPSC line SANi007-A from a patient with a heterozygous dominant mutation in ELANE.

Induced pluripotent stem cell (iPSC) line was generated from erythroblasts (EBLs) derived from a patient diagnosed with severe congenital neutropenia, caused by mutations in ELANE (c.614delG). Transgene-free iPSC line was generated using Sendai virus reprogramming.

Generation and characterization of a human iPSC line SANi008-A from a Chédiak-Higashi Syndrome patient.

Induced pluripotent stem cells (iPSCs) were generated from erythroblasts (EBLs) obtained from a patient diagnosed with Chédiak-Higashi Syndrome (CHS), caused by mutations in LYST (c.4322_4325delAGAG and c.10127A>G).

Generation and characterization of a control and patient-derived human iPSC line containing the Hermansky Pudlak type 2 (HPS2) associated heterozygous compound mutation in AP3B1.

Induced pluripotent stem cells (iPSCs) were generated from blood outgrowth endothelial cells (BOECs) obtained from a healthy donor and from a patient diagnosed with Hermansky Pudlak Syndrome type 2 (HPS2), caused by compound heterozygous AP3B1 mutations (c.177delA and c.1839-1842delTAGA).

Mechanical Stress Induces Ca-Dependent Signal Transduction in Erythroblasts and Modulates Erythropoiesis.

Bioreactors are increasingly implemented for large scale cultures of various mammalian cells, which requires optimization of culture conditions. Such upscaling is also required to produce red blood cells (RBC) for transfusion and therapy purposes. However, the physiological suitability of RBC cultures to be transferred to stirred bioreactors is not well understood.

CD14+ monocytes repress gamma globin expression at early stages of erythropoiesis.

In β-hemoglobinopathies, reactivation of gamma- at the expense of beta-globin is a prominent therapeutic option. Expression of the globin genes is not strictly intrinsically regulated during erythropoiesis, supported by the observation that fetal erythroid cells switch to adult hemoglobin expression when injected in mice. We show cultured erythroblasts are a mix of HbA restrictive and HbA/HbF expressing cells and that the proportion of cells in the latter population depends on the starting material.

Hemoglobin switching in mice carrying the variant.

Haploinsufficiency for transcription factor KLF1 causes a variety of human erythroid phenotypes, such as the In(Lu) blood type, increased HbA2 levels, and hereditary persistence of fetal hemoglobin. Severe dominant congenital dyserythropoietic anemia IV (OMIM 613673) is associated with the KLF1 p.E325K variant.

Large-scale in vitro production of red blood cells from human peripheral blood mononuclear cells.

Transfusion of donor-derived red blood cells (RBC) is the most common form of cellular therapy. Donor availability and the potential risk of alloimmunization and other transfusion-related complications may, however, limit the availability of transfusion units, especially for chronically transfused patients. In vitro cultured, customizable RBC would negate these concerns and further increase precision medicine.