ALBERT

Description: Author(s): Maud Versteegen, David Denis-Petit, Vincent Méot, Thomas Bonnet, Maxime Comet, Franck Gobet, Fazia Hannachi, Medhi Tarisien, Pascal Morel, Marco Martini, and Sophie Péru Photoactivation yield measurements on In 115 have been performed at the ELSA facility with Bremsstrahlung photon beams over a range of endpoint energies between 4.5 and 18 MeV. The measured photoexcitation yields of the In 115 m metastable state are compared with calculated yields using cross sections … [Phys. Rev. C 94, 044325] Published Fri Oct 28, 2016

Description: Background: Glucose transporter 1 (GLUT1) is a ubiquitously expressed protein highly expressed on the surface of erythrocytes. As a member of insulin signaling pathway, GLUT1 is responsible for basal and growth factor-stimulated glucose uptake. The insulin signaling pathway is involved in several different biologic functions including cellular metabolism, energy regulation, cell cycle control, and stress response. We have previously identified several components of the insulin signaling pathway, including FOXO3, AMPK, and IGFBP3, to be associated with fetal hemoglobin (HbF) levels in erythroid progenitor cells from sickle cell disease (SCD) patients. We have shown that metformin, a FOXO3 and AMPK activator, induces HbF in vitro. Furthermore, our preliminary data of metformin clinical trial in patients with SCD suggests that metformin can induce HbF in vivo. Studies in non-erythroid cells have reported that metformin increases production and surface expression of GLUT1; increase in the activated form of both AMPK and FOXO3 is also associated with elevated GLUT1 surface expression and its activation. Given these interesting associations, we hypothesized that GLUT1 levels may be associated with HbF levels in patients with SCD. To test this, we measured the expression levels of GLUT1 on the surface of red blood cells (RBC) from patients with SCD and investigated its correlation with hematologic indices. Methods: Applying a receptor binding domain labeling technique using anti GLUT1 antibody (Metafora Biosystems), we quantified GLUT1 expression measuring its geometric mean fluorescence intensity index on the surface of the RBCs by flow cytometry (Attune NxT). GLUT1 and CD71+ expression was measured on peripheral blood samples collected from 13 pediatric patients with HbSS (all on hydroxyurea, none on transfusion therapy) under an IRB approved protocol from Baylor College of Medicine. Patients ranged from 4 to 21 years of age; 52% were male. 4 HbAA normal donors were also analyzed, ages 28 to 43 years old, 50% male. HbF levels were obtained on the same date of collection by HPLC (Agilent, 1260 infinity-2). Complete blood count with differential and absolute reticulocyte count (ARC) was measured by ADVIA-120 hematology analyzer (Siemens). Flow cytometry data was analyzed by FlowJo software. P-values were calculated using Student's t-test. Results and conclusions: We identified a strong positive correlation between GLUT1 expression and HbF on the surface of hydroxyurea treated HbSS RBCs, R2=0.41. Possible variables contributing to this correlation are HU treatment differences, patient age, and RBC stage of maturation. However, 1) there was no correlation between GLUT1 levels and absolute neutrophil count (ANC), suggesting that variations in HU usage did not contribute to the association; 2) there was no association between patient age and GLUT1 levels; 3) there was also no correlation between GLUT1 levels and ARC or %CD71 positivity, suggesting that the GLUT1:HbF correlation was not due to more early stage erythroid cells with higher HbF levels due to a maturation arrest (Figure 1). GLUT1 expression was significantly higher on the surface of HbSS RBCs and CD71+ cells compared to HbAA (Figure 2); this is possibly due to the increased metabolic demand for glucose in the sickle RBC, but may also impact the basal HbF level of the sickle RBC. We hypothesize that cells with higher HbF levels have higher levels of activated AMPK, which activates FOXO3, a positive regulator of HbF (Zhang et al., Blood 2018), consistent with a metabolic stress state. Metabolic stress leads to an increase in GLUT1, to facilitate glucose transport. Future work will explore potential causative relationships between GLUT1 levels and HbF, and determine whether pharmacologic manipulation of GLUT1 may increase HbF in patients with SCD. Disclosures Petit: Metafora-biosystems: Equity Ownership, Other: CEO and co-founder.

Description: Recent studies have documented that cell metabolism regulates hematopoietic stem cell (HSC) renewal and lineage commitment. However, the detailed metabolic changes that occur during human erythropoiesis remain to be defined. As erythroid cell differentiation is likely to be associated with changes in metabolic requirements, we hypothesized that progenitors adapt to these metabolic modulations by altering their nutrient transporter expression profile. Using an in vitro erythroid-inducing cell culture system employing CD34+ cells from human bone marrow and peripheral blood as well as primary erythroid cells isolated from fresh bone marrow samples, we assessed the cell surface nutrient transporter profiles of progenitors at different stages of erythroid development. Quantification of cell surface nutrient transporter expression was performed using a novel scaffold of retroviral envelope receptor binding domains (RBDs) that function as specific ligands of solute carrier (SLC) nutrient transporters. This bank allowed an evaluation of diverse metabolite transporters including GLUT1/SLC2A1 glucose transporter, the PiT1/SLC20A1 and PiT2/SLC20A2 phosphate importers, the XPR1/SLC53A1 phosphate exporter, the FLVCR1 heme exporter, the RFVT1/2 (SLC52A1/SLC52A2) riboflavin importers, the CAT1/SLC7A1 arginine importer, the ASCT2/SLC1A5 glutamine transporter and the SMVT/SLC5A6 sodium-dependent multivitamin transporter. Notably, the cell surface expression profiles of these nutrient transporters, as evaluated by flow cytometry, revealed marked changes as a function of the stage of erythroid differentiation, as shown in the figure below. Specifically, while FLVCR1, RFVT1/2, and SMVT are highly expressed on erythroid progenitors, the levels of these transporters decrease starting at the proerythroblast stage. In addition, PiT1, PiT2, XPR1, and CAT1 are expressed highly during the erythroid colony forming unit (CFU-E) stage while GLUT1 gradually increases and reaches a peak at late stages of erythroid differentiation, remaining elevated on mature red cells. The noted distinct changes in transporter expression are likely a reflection of the changing demands of various nutrients during human erythropoiesis. In summary, we have established a comprehensive metabolite transporter profile at distinct stages of normal human erythropoiesis using a novel experimental strategy. These original findings form a strong foundation for future studies aiming at elucidating the metabolic requirements of normal erythropoiesis, evaluating diseases affecting red blood cell maturation due to aberrant metabolic regulation, and for identifying new therapeutic targets. Figure Disclosures Bitaudeau: Metafora-biosystems: Employment. Petit:Metafora-biosystems: Equity Ownership, Other: CEO and co-founder. Sitbon:Metafora-biosystems: Membership on an entity's Board of Directors or advisory committees, Other: Co-founder.

Description: The human genome encodes numerous enzymes capable of deaminating polynucleotides. While they are capable of exquisite specificity, occasionally they result in hypermutation where up to 90 per cent of cytidine or adenosine residues may be edited. As such, they constitute a formidable anti-viral barrier, for no virus can survive such a high mutation rate. As the APOBEC3 group of cytidine deaminases edit single-stranded viral DNA, the crucial question is can they hyperedit chromosomal DNA? Everything points to a positive answer. Nonetheless, hypermutants per se have not yet been described, probably being countered by highly efficient mismatch repair. For the APOBEC3 genes, not only is their physiological function unknown, but also their role in the induction of cancer remains to be determined. Yet given the pace of research, all this is certain to change in the next few years.

Description: One of the top priorities of the aquaculture industry is the genetic improvement of economically important traits in fish, such as those related to processing and quality. However, the accuracy of genetic evaluations has been hindered by a lack of data on such traits from a sufficiently large population of animals. The objectives of this study were thus threefold: (i) to estimate genetic parameters of growth-, yield-, and quality-related traits in rainbow trout (Oncorhynchus mykiss) using three different phenotyping technologies [invasive and non-invasive: microwave-based, digital image analysis, and magnetic resonance imaging (MRI)], (ii) to detect quantitative trait loci (QTLs) associated with these traits, and (iii) to identify candidate genes present within these QTL regions. Our study collected data from 1,379 fish on growth, yield-related traits (body weight, condition coefficient, head yield, carcass yield, headless gutted carcass yield), and quality-related traits (total fat, percentage of fat in subcutaneous adipose tissue, percentage of fat in flesh, flesh colour); genotypic data were then obtained for all fish using the 57K SNP Axiom® Trout Genotyping array. Heritability estimates for most of the 14 traits examined were moderate to strong, varying from 0.12 to 0.67. Most traits were clearly polygenic, but our genome-wide association studies (GWASs) identified two genomic regions on chromosome 8 that explained up to 10% of the genetic variance (cumulative effects of two QTLs) for several traits (weight, condition coefficient, subcutaneous and total fat content, carcass and headless gutted carcass yields). For flesh colour traits, six QTLs explained 1–4% of the genetic variance. Within these regions, we identified several genes (htr1, gnpat, ephx1, bcmo1, and cyp2x) that have been implicated in adipogenesis or carotenoid metabolism, and thus represent good candidates for further functional validation. Finally, of the three techniques used for phenotyping, MRI demonstrated particular promise for measurements of fat content and distribution, while the digital image analysis-based approach was very useful in quantifying colour-related traits. This work provides new insights that may aid the development of commercial breeding programmes in rainbow trout, specifically with regard to the genetic improvement of yield and flesh-quality traits as well as the use of invasive and/or non-invasive technologies to predict such traits.