Somatic insulin signaling regulates a germline starvation response in Drosophila egg chambers

AbstractEgg chambers from starved Drosophila females contain large aggregates of processing (P) bodies and cortically enriched microtubules. As this response to starvation is rapidly reversed upon re-feeding females or culturing egg chambers with exogenous bovine insulin, we examined the role of endogenous insulin signaling in mediating the starvation response. We found that systemic Drosophila insulin-like peptides (dILPs) activate the insulin pathway in follicle cells, which then regulate both microtubule and P body organization in the underlying germline cells. This organization is modulated by the motor proteins Dynein and Kinesin. Dynein activity is required for microtubule and P body organization during starvation, while Kinesin activity is required during nutrient-rich conditions. Blocking the ability of egg chambers to form P body aggregates in response to starvation correlated with reduced progeny survival. These data suggest a potential mechanism to maximize fecundity even during periods of poor nutrient availability, by mounting a protective response in immature egg chambers

Generation of human erythroblast-derived iPSC line using episomal reprogramming system

Peripheral blood mononuclear cells were isolated and cultured to a pure pro-EBL population and reprogrammed using episomal plasmids. The pluripotency of transgene-free induced pluripotent stem cell (iPSC) line was verified by the expression of pluripotency-associated markers and by in vitro spontaneous differentiation towards the 3 germ layers. The iPSC line showed normal karyotype. Peripheral blood is a non-invasive easy accessible cell source and combined with EBL outgrowth in vitro, a routine process obtaining sufficient amount of homogenous cells can be obtained within a week. Using episomal delivery, pro-EBLs can be reprogrammed in a transgene-free, cost effective system

Generation and characterization of human iPSC lines SANi001-A and SANi002-A from mobilized peripheral blood derived megakaryoblasts

Mobilized peripheral blood (MPB) CD34+ cells were differentiated to CD34+/CD41+ megakaryoblasts. Cells were sorted to obtain a pure megakaryoblast population which was reprogrammed with a hOKSM self-silencing polycistronic lentiviral vector. Resulting iPSC showed normal karyotype and expression of pluripotency associated markers and in vitro spontaneous differentiation towards the 3 germ layers confirmed pluripotency of iPSC lines. Besides normal iPSC applications, these lines can be used as a control line for other megakaryoid origin iPSC and could be applied for epigenetic based research

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). BOECs were reprogrammed with a hOKSM self-silencing polycistronic lentiviral vector, where the generated iPSCs showed normal karyotype, expression of pluripotency associated markers and in vitro spontaneous differentiation towards the three germ layers. The generated iPSCs can be used to study HPS2 pathophysiology and the basic functions of AP3B1 protein in different cell types.</p

Generation and characterization of a human iPSC line SANi005-A containing the gray platelet associated heterozygous mutation p.Q287*in GFI1B

Peripheral blood mononuclear cells were isolated from an individual harboring a heterozygous c.859C -> T p.Q287* mutation in GFI1B, causing an autosomal dominant bleeding disorder, platelet type, 17 (BDPLT17). PBMCs were differentiated to erythroblasts and reprogrammed by lentiviral delivery of a self-silencing hOKSM polycistronic vector. Pluripotency of iPSC line was confirmed by expression of associated markers and by in vitro spontaneous differentiation towards the 3 germ layers. Normal karyotype confirmed the genomic integrity of iPSCs and the presence of disease causingmutationwas shown by Sanger sequencing. The generated iPSCs can be used to study BDPLT17 pathophysiology and basic functions of GFI1B. (c) 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND licens

From polymers to proteins: the effect of side chains and broken symmetry on the formation of secondary structures within a Wang-Landau approach

We use a micro-canonical Wang-Landau technique to study the equilibrium properties of a single flexible homopolymer where consecutive monomers are represented by impenetrable hard spherical beads tangential to each other, and non-consecutive monomers interact via a square-well potential. To mimic the characteristics of a protein-like system, the model is then refined in two different directions. Firstly, by allowing partial overlap between consecutive beads, we break the spherical symmetry and thus provide a severe constraint on the possible conformations of the chain. Alternatively, we introduce additional spherical beads at specific positions in the direction normal to the backbone, to represent the steric hindrance of the side chains in real proteins. Finally, we consider also a combination of these two ingredients. In all three systems, we obtain the full phase diagram in the temperature-interaction range plane and find the presence of helicoidal structures at low temperatures in the intermediate range of interactions. The effect of the range of the square-well attraction is highlighted, and shown to play a role similar to that found in simple liquids and polymers. Perspectives in terms of protein folding are finally discussed