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In β-thalassemia, mutations in the HBBgene cause reduced β-globin synthesis with accumulation of toxic free α-globin, leading to ineffective erythropoiesis and hemolysis. We showed previously that β-thalassemic erythroblasts can eliminate free α-globin by ULK1-mediated autophagy and that this process is stimulated by rapamycin inhibition of mTORC1, which phosphorylates ULK1 to inhibit its activity. Several studies have shown that iron restriction can reduce the accumulation of free α-globin precipitates to alleviate the pathophysiology of β-thalassemia. Considering that iron stimulates mTORC1 activity in numerous cell types including erythroblasts, we tested the hypothesis that iron restriction alleviates β-thalassemia by inhibiting mTORC1, thereby stimulating ULK1-mediated autophagy of free α-globin.

•Loss of miR-144/451in erythroid cells of Hbbth3/+mice alleviates β-thalassemia by stimulating ULK1-dependent autophagy of free α-globin.•Loss of miR-144/451stimulates ULK1 by activating the LKB1/AMPK axis and inducing erythroblast iron restriction.

BackgroundHyperleukocytosis is observed in 5% to 20% of patients with newly diagnosed acute myeloid leukemia (AML) and is associated with an increased risk of early complications and mortality. While being used frequently in patients with AML and hyperleukocytosis, the clinical utility of leukapheresis has not been conclusive. Low-dose chemotherapy has also been used recently as a cytoreduction method in these patients, but the data are limited.

Pui: Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: Data Monitoring Committee.

Background:Prolonged thrombocytopenia after hematopoietic stem cell transplant is a relatively common complication associated with intricate mechanisms including impaired thrombopoiesis and increased platelet turnover. Platelet recovery is particularly delayed after umbilical cord blood transplant (UCBT). Romiplostim is a thrombopoietin receptor agonist that is FDA approved for the treatment of chronic ITP. Although an increasing number of studies recently show promising results on the use of romiplostim in chemotherapy induced thrombocytopenia, the effect of romiplostim on platelet recovery in patients with persistent thrombocytopenia after UCBT remains unknown.

Wagner: BlueRock: Research Funding; Rocket Pharmaceuticals: Consultancy; Novartis: Research Funding; Magenta: Consultancy, Research Funding; Gadeta: Membership on an entity's Board of Directors or advisory committees. Brunstein:Gamida: Research Funding; Magenta: Research Funding; Astex: Research Funding. Bejanyan:Kiadis Pharma: Other: advisory board. Smith:Amgen: Research Funding; Jazz Pharmaceuticals: Research Funding.Romiplostim (Nplate) is an FDA approved drug for chronic ITP. In this study (phase I trial) we aimed to evaluate the safety and effectiveness of romiplostim on platelet recovery following UCBT.

No relevant conflicts of interest to declare.

No relevant conflicts of interest to declare.

CDAR (ClinicalTrials.gov Identifier: NCT02964494), a registry for patients with Congenital Dyserythropoietic Anemia (CDA) in North America, was recently created with the goal to provide a longitudinal database and associated biorepository to facilitate natural history studies and research on the molecular pathways involved in the pathogenesis of CDAs. A 2 y.o. female patient with transfusion dependent anemia, pathologic diagnosis of Congenital Dyserythropoietic Anemia type I (CDA-I), and neurodevelopmental delay was enrolled in CDAR. Next Generation sequencing and deletion/duplication assay identified no mutations in the known CDA-associated genes, including CDAN1and C15orf41, which are causative for CDA-I. Whole-exome sequencing for the patient and her parents (family-trio design) revealed a novel, de novo VPS4Amissense variant located in the last codon of exon 8, potentially affecting splicing. VPS4A is an ATPase which, in association with the endosomal sorting complex required for transport (ESCRT), has been shown to play a critical role in cell division of HeLa cells in vitro, concentrating at the spindle poles during mitosis and at the midbody during cytokinesis. The aim of this work is to validate the pathogenetic role of the VPS4Avariant for CDA and further investigate the role of VPS4A in erythroblast mitosis and cytokinesis.

Background

Several members of the Ras-GTPases have been shown to play major roles as molecular switches in various signaling pathways in hematopoietic cells. The roles of Ras/MAPKs/ERK signaling pathways in EPO-induced erythroid differentiation have been explored in the past on animal models. Recently, the Ras/RalGEFs/Ral pathway has been a focus of research in oncology given its roles in tumorigenesis. However, its role in normal human erythropoiesis is poorly understood. The seven RalGEF family members are guanine nucleotide exchange factors with unique as well as overlapping roles. They bridge activated Ras to activation of RalA and RalB while they have also been shown to promote Akt activation. Recently, we identified and characterized a homozygous splicing variant (c.1580+4T>A) in RGL2 (Ral Guanine Nucleotide Dissociation Stimulator-Like 2) gene, one of the RalGEFs, in a 16 month-old female patient with a recessive form of familial syndromic pancytopenia, more severe in the erythroid lineage with transfusion-dependent anemia, hepatosplenomegaly, liver fibrosis, and cardiac dysfunction. We verified by RT-PCR that this splicing variant was associated by a decrease in the RGL2 expression levels by 70-96% in the white blood cells and reticulocytes of the patient. We hypothesized that decreased RGL2 expression leads to defective human erythropoiesis by altering terminal erythroid differentiation, erythroblast cell cycle progression and/or apoptosis.

No relevant conflicts of interest to declare.

No relevant conflicts of interest to declare.

Quinn: Amgen: Research Funding; Eli Lilly: Research Funding; Silver Lake Research Corporation: Consultancy. Joiner:Global Blood Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees.

The Hereditary Hemolytic Anemias (HHAs) are a genetically heterogeneous group of anemias characterized by decreased red blood cell (RBC) survival because of defects in hemoglobin, RBC membrane proteins or enzymes. The diagnosis of this group of disorders is complex and challenging requiring analysis of the morphology of RBCs, hemoglobin electrophoresis, and a battery of phenotypic assays. The phenotypic analysis is often problematic in transfusion dependent patients or at times of presentation with a hemolytic crisis as transfused blood or reticulocytosis confounds diagnostic testing. Molecular genetic testing has grown in popularity in the diagnosis of hereditary hemolytic anemias as it is not affected by transfusions or other clinical variables and provides additional insight into the mechanism of the disease. We have developed a Next Generation Sequencing (NGS) panel for HHA due to RBC membrane disorders and enzymopathies and congenital dyserythropoietic anemias (CDA). CDAs, although collectively rare, are included in the panel as they are occasionally misdiagnosed as hereditary spherocytosis (HS) due to their clinical characteristics of hemolysis, increased osmotic fragility, and splenomegaly albeit with inadequate reticulocytosis

Cardiopulmonary complications are an important contributor to morbidity and mortality in patients with sickle cell anemia (SCA). We have recently discovered that patients with SCA develop cardiomyopathy with restrictive pattern, characterized by diastolic dysfunction with progressive left atrial dilation, superimposed on the anemia-associated hyperdynamic physiology causing hypertrophied, dilated ventricles (Niss et al, JACC: Cardiovascular Imaging, 2016). Using a longitudinal systematic analysis of mouse models of SCA versus mice with iron-deficiency anemia, we found that this unique cardiomyopathy is indeed not due to chronic anemia and is associated with upregulation of genes related to oxidative stress pathways (Bakeer et al, PNAS, in press). These findings along with the known fact of increased inflammation and oxidative stress in SCA led us to postulate that NADPH oxidase (Nox)-mediated reactive oxygen species (ROS) may be an important pathogenic mechanism underlying cardiomyopathy in SCA and consequently mice lacking Nox-mediated ROS might be relatively protected from cardiac dysfunction.

Although Sickle Cell Anemia (SCA) is caused by a single nucleotide mutation in the beta globin gene, there is broad phenotypic variability in affected individuals. It would be highly advantageous to be able to predict which SCA patients are most likely to suffer severe complications and which are likely to benefit from specific treatments. Since two of the major pathologic mechanisms in SCA are erythrocyte dehydration and chronic inflammation, alterations in the expression and/or function of proteins affecting these processes may be responsible for heterogeneity in SCA phenotype. We have developed a 23-gene Next-Generation sequencing panel to identify variants in genes involved in erythrocyte hydration and in reactive oxygen species (ROS) generation and reduction in patients with SCA. We have collected blood samples from an initial cohort of 18 SCA patients with severe phenotype, defined by history of stroke or abnormal transcranial Doppler velocities, and 13 SCA patients with mild phenotype for DNA preparation and for specialized testing to evaluate erythrocyte hydration status and ROS generation.