23 research outputs found
Phenotype instability of hepatocyte-like cells produced by direct reprogramming of mesenchymal stromal cells
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Previous issue date: 2020Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB), Conselho
Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / São Rafael Hospital. Center for Biotechnology and Cell Therapy, Salvador, BA, Brazil.MRC Centre for Regenerative Medicine. Edinburgh, UK.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / São Rafael Hospital. Center for Biotechnology and Cell Therapy, Salvador, BA, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / São Rafael Hospital. Center for Biotechnology and Cell Therapy, Salvador, BA, Brazil / D’Or Institute for Research and Education. Rio de Janeiro, RJ, Brazil.Universidade Federal da Bahia. Institute of Health Sciences. Salvador, BA, Brasil.MRC Centre for Regenerative Medicine. Edinburgh, UK.São Rafael Hospital. Center for Biotechnology and Cell Therapy, Salvador, BA, Brazil / D’Or Institute for Research and Education. Rio de Janeiro, RJ, Brazil.São Rafael Hospital. Center for Biotechnology and Cell Therapy, Salvador, BA, Brazil / D’Or Institute for Research and Education. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / National Institute of Science and Technology for Regenerative Medicine. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / São Rafael Hospital. Center for Biotechnology and Cell Therapy, Salvador, BA, Brazil.MRC Centre for Regenerative Medicine. Edinburgh, UK.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / National Institute of Science and Technology for Regenerative Medicine. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / São Rafael Hospital. Center for Biotechnology and Cell Therapy, Salvador, BA, Brazil / D’Or Institute for Research and Education. Rio de Janeiro, RJ, Brazil / National Institute of Science and Technology for Regenerative Medicine. Rio de Janeiro, RJ, Brazil /Hepatocyte-like cells (iHEPs) generated by transcription factor-mediated direct reprogramming of somatic cells have been studied as potential cell sources for the development of novel therapies targeting liver diseases. The mechanisms involved in direct reprogramming, stability after long-term in vitro expansion, and safety profile of reprogrammed cells in different experimental models, however, still require further investigation. Methods: iHEPs were generated by forced expression of Foxa2/Hnf4a in mouse mesenchymal stromal cells and
characterized their phenotype stability by in vitro and in vivo analyses.
Results: The iHEPs expressed mixed hepatocyte and liver progenitor cell markers, were highly proliferative, and
presented metabolic activities in functional assays. A progressive loss of hepatic phenotype, however, was observed
after several passages, leading to an increase in alpha-SMA+ fibroblast-like cells, which could be distinguished and
sorted from iHEPs by differential mitochondrial content. The resulting purified iHEPs proliferated, maintained liver
progenitor cell markers, and, upon stimulation with lineage maturation media, increased expression of either biliary
or hepatocyte markers. In vivo functionality was assessed in independent pre-clinical mouse models. Minimal
engraftment was observed following transplantation in mice with acute acetaminophen-induced liver injury. In
contrast, upon transplantation in a transgenic mouse model presenting host hepatocyte senescence, widespread
engraftment and uncontrolled proliferation of iHEPs was observed, forming islands of epithelial-like cells, adipocytelike
cells, or cells presenting both morphologies.
Conclusion: The results have significant implications for cell reprogramming, suggesting that iHEPs generated by
Foxa2/Hnf4a expression have an unstable phenotype and depend on transgene expression for maintenance of
hepatocyte-like characteristics, showing a tendency to return to the mesenchymal phenotype of origin and a
compromised safety profil
The phylogenetic relationships and molecular systematics of scincid lizards of the genus Heremites
Ecological niche differentiation and taxonomic distinction between <i>Eremias strauchi strauchi</i> and <i>Eremias strauchi kopetdaghica</i> (Squamata: Lacertidae) on the Iranian Plateau based on ecological niche modeling
<p><i>Eremias strauchi strauchi</i> and <i>Eremias strauchi kopetdaghica</i> are genetically and morphologically distinct and are distributed allopatrically in northeastern and northwestern Iran. <i>E. s. strauchi</i> is distinguishable by having green spots on lateral parts of the body, while <i>E. s. kopetdaghica</i> is characterized by white spots and irregular black dots on lateral parts of the body. Recent molecular studies have suggested that these are two distinct species, but other types of analyses leave their classification unclear. In this study, we evaluated their taxonomic status using additional data (including ecological niches) to confirm the hypothesis that they are two species. All known records of their occurrence were employed to predict and evaluate the suitable areas where they may be expected to be found in Iran. We then performed niche similarity tests (niche identity and background tests) and point-based analyses to compare their ecological niches and explain ecological differentiation. Niche models of <i>E. s. strauchi</i> and <i>E. s. kopetdaghica</i> had good results and powerful performance based on high area under the curve (AUC) values [<i>E. s. strauchi</i> = 0.992, standard deviation (SD) = ± 0.008; <i>E. s. kopetdaghica</i> = 0.978, SD = ± 0.032]. Ecological differentiation has been found across the entire range, indicating that ecological differentiation had an important role in species differentiation. Environmental conditions for the species diverged along environmental variables, as precipitation of coldest quarter for the “Strauch” subspecies and precipitation of warmest quarter for the “Kopet dagh” subspecies were most important in determining habitat suitability, respectively. These two factors are important in niche differentiation between the two species and influenced their genetic divergence. Finally, our results confirmed the niche differentiation between <i>E. s. strauchi</i> and <i>E. s. kopetdaghica</i> and added new insights into the taxonomic distinction between <i>E. s. strauchi</i> and <i>E. s. kopetdaghica</i>.</p
Intraerythrocytic rickettsial inclusions in endangered Kaiser’s mountain newt, Neurergus kaiseri
Ecological niche differentiation and taxonomic distinction between Eremias strauchi strauchi
Neogene climatic oscillations shape the biogeography and evolutionary history of the Eurasian blindsnake
Typhlops vermicularis is the only extant scolecophidian representative occurring in Europe. Its main distribution area, the eastern Mediterranean, has a complicated geological and climatic history that has left an imprint on the phylogenies and biogeography of many taxa, especially amphibians and reptiles. Since reptiles are sensitive indicators of palaeogeographical and palaeoclimatic events, we investigated the intraspecific genealogy of T. vermicularis in a phylogeographical framework. A total of 130 specimens were analyzed, while the use of formalin and ethanol as preservatives called for a special treatment of the samples. Partial sequences of two mitochondrial (12S and ND2) and one nuclear (PRLR) marker were targeted and the results of the phylogenetic analyses (NJ, ML and BI) and the parsimony-network revealed the existence of 10 evolutionary significant units within this species. In combination with the results of the dispersal-vicariance analysis, we may conclude that the Eurasian blindsnake has encountered a sequence of extinction events, followed by secondary expansion from refugia. Estimation of divergence times showed that severe climatic changes between significantly wetter and drier conditions in the Late Neogene have played a key role on the evolutionary and biogeographical history of T. vermicularis. Additionally, both markers (mtDNA and nDNA) distinguished a largely-differentiated evolutionary lineage (Jordan and south Syria), which could even be reckoned as a full species. Our study reveals the existence of cryptic evolutionary lineages within T. vermicularis, which calls for further attention both on the protection of intraspecific varieties and the respective geographic areas that hold them. (C) 2011 Elsevier Inc. All rights reserved