Differentiation of Mesenchymal Stem Cells Derived from Pancreatic Islets and Bone Marrow into Islet-Like Cell Phenotype
PLOS ONE
Authors: Zanini, Cristina; Bruno, Stefania; Mandili, Giorgia; Baci, Denisa; Cerutti, Francesco; Cenacchi, Giovanna; Izzi, Leo; Camussi, Giovanni; Forni, Marco
Abstract
Background: Regarding regenerative medicine for diabetes, accessible sources of Mesenchymal Stem Cells (MSCs) for induction of insular beta cell differentiation may be as important as mastering the differentiation process itself. Methodology/Principal Findings: In the present work, stem cells from pancreatic islets (human islet-mesenchymal stem cells, HI-MSCs) and from human bone marrow (bone marrow mesenchymal stem cells, BM-MSCs) were cultured in custom-made serum-free medium, using suitable conditions in order to induce differentiation into Islet-like Cells (ILCs). HI-MSCs and BM-MSCs were positive for the MSC markers CD105, CD73, CD90, CD29. Following this induction, HI-MSC and BM-MSC formed evident islet-like structures in the culture flasks. To investigate functional modifications after induction to ILCs, ultrastructural analysis and immunofluorescence were performed. PDX1 (pancreatic duodenal homeobox gene-1), insulin, C peptide and Glut-2 were detected in HI-ILCs whereas BM-ILCs only expressed Glut-2 and insulin. Insulin was also detected in the culture medium following glucose stimulation, confirming an initial differentiation that resulted in glucose-sensitive endocrine secretion. In order to identify proteins that were modified following differentiation from basal MSC (HI-MSCs and BM-MSCs) to their HI-ILCs and BM-ILCs counterparts, proteomic analysis was performed. Three new proteins (APOA1, ATL2 and SODM) were present in both ILC types, while other detected proteins were verified to be unique to the single individual differentiated cells lines. Hierarchical analysis underscored the limited similarities between HI-MSCs and BM-MSCs after induction of differentiation, and the persistence of relevant differences related to cells of different origin. Conclusions/Significance: Proteomic analysis highlighted differences in the MSCs according to site of origin, reflecting spontaneous differentiation and commitment. A more detailed understanding of protein assets may provide insights required to master the differentiation process of HI-MSCs to functional beta cells based only upon culture conditioning. These findings may open new strategies for the clinical use of BM-MSCs in diabetes.
ER-shaping atlastin proteins act as central hubs to promote flavivirus replication and virion assembly
NATURE MICROBIOLOGY
Authors: Neufeldt, Christopher J.; Cortese, Mirko; Scaturro, Pietro; Cerikan, Berati; Wideman, Jeremy G.; Tabata, Keisuke; Moraes, Thais; Oleksiuk, Olga; Pichlmair, Andreas; Bartenschlager, Ralf
Abstract
Flaviviruses, including dengue virus and Zika virus, extensively remodel the cellular endomembrane network to generate replication organelles that promote viral genome replication and virus production. However, it remains unclear how these membranes and associated cellular proteins act during the virus cycle. Here, we show that atlastins (ATLs), a subset of ER resident proteins involved in neurodegenerative diseases, have dichotomous effects on flaviviruses-with ATL2 depletion leading to replication organelle defects, and ATL3 depletion to changes in virus production pathways. We characterized non-conserved functional domains in ATL paralogues and show that the ATL interactome is profoundly reprogrammed following dengue virus infection. Screen analysis confirmed non-redundant ATL functions and identified a specific role for ATL3, and its interactor ARF4, in vesicle trafficking and virion maturation. Our data identify ATLs as central hubs targeted by flaviviruses to establish their replication organelle and to achieve efficient virion maturation and secretion.