The quest for non-coding RNAs (ncRNAs) in the last few years has revealed a surprisingly large number of small RNAs belonging to previously known as well as entirely novel classes. Computational and experimental approaches have uncovered new ncRNAs in all kingdoms of life. In this work, we used a shotgun cloning approach to construct full-length cDNA libraries of small RNAs from the eukaryotic model organism Dictyostelium discoideum. Interestingly, two entirely novel classes of RNAs were identified of which one is developmentally regulated. The RNAs within each class share conserved 5'- and 3'-termini that can potentially form stem structures. RNAs of both classes show predominantly cytoplasmic localization. In addition, based on conserved structure and/or sequence motifs, several of the identified ncRNAs could be divided into classes known from other organisms, e.g. 18 small nucleolar RNA candidates (17 box C/D, of which a few are developmentally regulated, and one box H/ACA). Two ncRNAs showed a high degree of similarity to the small nuclear U2 RNA and signal recognition particle RNA (SRP RNA), respectively. Furthermore, the majority of the regions upstream of the sequences encoding the isolated RNAs share conserved motifs that may constitute new promoter elements.

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Human hepatocytes display substantial functional inter-individual variation regarding drug metabolizing functions. In order to investigate if this diversity is mirrored in hepatocytes derived from different human pluripotent stem cell (hPSC) lines, we evaluated 25 hPSC lines originating from 24 different donors for hepatic differentiation and functionality. Homogenous hepatocyte cultures could be derived from all hPSC lines using one standardized differentiation procedure. To the best of our knowledge this is the first report of a standardized hepatic differentiation procedure that is generally applicable across a large panel of hPSC lines without any adaptations to individual lines. Importantly, with regard to functional aspects, such as Cytochrome P450 activities, we observed that hepatocytes derived from different hPSC lines displayed inter-individual variation characteristic for primary hepatocytes obtained from different donors, while these activities were highly reproducible between repeated experiments using the same line. Taken together, these data demonstrate the emerging possibility to compile panels of hPSC-derived hepatocytes of particular phenotypes/genotypes relevant for drug metabolism and toxicity studies. Moreover, these findings are of significance for applications within the regenerative medicine field, since our stringent differentiation procedure allows the derivation of homogenous hepatocyte cultures from multiple donors which is a prerequisite for the realization of future personalized stem cell based therapies.

Background: Carbohydrate epitopes are often used as markers for characterization of human embryonic stem cells (hESC). Results: Several glycosphingolipids not previously found in hESC were characterized. Conclusion: The glycosylation of hESC is more complex than previously thought. Significance: These findings will help to understand the immunogenicity of hESC and might impact future applications in regenerative medicine.

Background: Carbohydrate epitopes are often used as markers for characterization of human pluripotent stem cells (hPSC).Results: Sialyl-lactotetra is highly expressed on the cell surface of hPSC lines, and the expression decreased upon early differentiation.Conclusion: Sialyl-lactotetra is a novel marker of undifferentiated human stem cells.Significance: These findings might impact future applications in regenerative medicine.