Generation of integration-free induced hepatocytes from mouse fibroblasts
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE67362 | GEO | 2015/03/27
SECONDARY ACCESSION(S): PRJNA279589
REPOSITORIES: GEO
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Project description:Previous studies demonstrated that hepatocyte-specific transcription factors could directly convert fibroblasts into functional hepatocytes-like cells, namely induced hepatocytes (iHeps) using viral systems. However, viral integration into host genome causes insertional mutation and risk of tumorigenecity. we showed iHeps could be generated from MEFs using the integration-free system. They were expandable in vitro and showed hepatic features, similar to primary hepatocytes. iHeps_G4H1F3 transfected (Episomal vectors) and iHeps_G4H1F3 transduced (pMXs) were duplicate, respectively. MEFs and primary hepatocytes were used as negative and positive controls, respectively.
2015-03-27 | E-GEOD-67362 | biostudies-arrayexpress
Project description:Recent studies have shown that defined sets of transcription factors could directly convert fibroblasts into induced hepatocytes (iHeps). However, the underlying mechanism of direct conversion process toward a hepatic lineage is largely unknown. Here, we report that the direct conversion kinetics from fibroblasts into iHeps throughout screening multiple additional factors that potentially rescue the delayed kinetics of MET and hepatic program. Mouse embryonic fibroblasts (MEFs) were efficiently converted into iHeps in the presence of c-Myc and Klf4 (CK), the activators for MET process, with the previously defined sets of hepatic transcription factors, resulting in remarkably improved generation of iHeps. Furthermore, in the presence of CK, Hnf4? alone could convert fibroblasts into iHeps within 5 days with a relatively higher efficiency. Cells transduced with different combinations of factors were cultured in standard Hep medium. Epithelial colonies were observed within 5 days with much higher numbers in the presence of additional factor, c-Myc and Klf4, compared to control group, indicating the number of epithelial colony was dramatically increased in the presence of additional stem cell factors
2013-12-03 | E-GEOD-52566 | biostudies-arrayexpress
Project description:Recent studies demonstrated that fibroblasts could be converted into induced neural stem cells (iNSCs). However, the insertional mutation caused by random integration of viral vectors has been a major limitation of iNSCs for the future clinical translation. Here we show that non-viral transfection of episomal vectors encoding Brn4/Pou3f4, Sox2, Klf4, and c-Myc sufficiently generates iNSCs. The episomal vector mediated iNSCs closely resemble brain-derived NSCs as well as iNSCs generated by retrovirus in morphology, gene expression profile, epigenetic status, self-renewal capacity and both in vitro and in vivo differentiation capacity. The novel conversion protocol defined in the current study offers a method for generating integration-free iNSCs for the clinical research we developed a novel method for generating integration-free iNSCs. We demonstrated that oriP/EBNA1-based episomal vectors could generate iNSCs by single transfection
2015-03-27 | E-GEOD-67319 | biostudies-arrayexpress
Project description:Recent studies demonstrated that fibroblasts could be converted into induced neural stem cells (iNSCs). However, the insertional mutation caused by random integration of viral vectors has been a major limitation of iNSCs for the future clinical translation. Here we show that non-viral transfection of episomal vectors encoding Brn4/Pou3f4, Sox2, Klf4, and c-Myc sufficiently generates iNSCs. The episomal vector mediated iNSCs closely resemble brain-derived NSCs as well as iNSCs generated by retrovirus in morphology, gene expression profile, epigenetic status, self-renewal capacity and both in vitro and in vivo differentiation capacity. The novel conversion protocol defined in the current study offers a method for generating integration-free iNSCs for the clinical research
2015-03-27 | GSE67319 | GEO
Project description:Induced pluripotent stem cell-derived human hepatocyte-like cells (iHeps) could provide a powerful tool for studying the mechanisms underlying human liver development and disease, testing the efficacy and safety of pharmaceuticals across different patients (i.e. personalized medicine), and enabling cell-based therapies in the clinic. However, current in vitro protocols that rely upon growth factors and extracellular matrices (ECM) alone yield iHeps with low levels of liver functions relative to adult primary human hepatocytes (PHHs). Moreover, these low hepatic functions in iHeps are difficult to maintain for prolonged times (weeks to months) in culture. Here, we engineered a micropatterned co-culture (iMPCC) platform in a multi-well format that, in contrast to conventional confluent cultures, significantly enhanced the functional maturation and longevity of iHeps in culture for 4 weeks in vitro when benchmarked against multiple donors of PHHs. In particular, iHeps were micropatterned onto collagen-coated domains of empirically optimized dimensions, surrounded by 3T3-J2 murine embryonic fibroblasts, and then sandwiched with a thin layer of ECM gel (Matrigel™). We assessed iHep maturity via global gene expression profiles, hepatic polarity, secretion of albumin and urea, basal CYP450 activities, phase-II conjugation, drug-mediated CYP450 induction, and drug-induced hepatotoxicity. Conclusion: Controlling both homotypic interactions between iHeps and heterotypic interactions with stromal fibroblasts significantly matures iHep functions and maintains them for several weeks in culture. In the future, iMPCCs could prove useful for drug screening, studying molecular mechanisms underlying iHep differentiation, modeling liver diseases, and integration into human-on-a-chip systems being designed to assess multi-organ responses to compounds. We used Affymetrix microarrays to profile the global gene expression of co-culture stabilized iHeps (iMPCCs) relative to freshly isolated and co-culture stabilized primary human hepatocytes (2 donors). To assess the transcriptomic stability of iHeps in iMPCCs, RNA was extracted following 9 and 21 days of culture for hybridization to Affymetrix microarrays. The hepatic maturation state of iHeps was assessed by comparing gene expression against microarrays containing data from two primary human hepatocyte donors, both following hepatocyte isolation (day 0) and after stabilization in the micropatterened co-culture platform (day 6 and day 42 MPCCs), as previously described.
2015-02-01 | E-GEOD-62962 | biostudies-arrayexpress
Project description:Retroviral integration is catalyzed by a tetramer of integrase (IN) assembled on viral DNA ends in a stable complex, known as the intasome. How the intasome interfaces with chromosomal DNA, which exists in the form of nucleosomal arrays, is currently unknown. Here we show that the prototype foamy virus (PFV) intasome is proficient at stable capture of nucleosomes as targets for integration. Single-particle cryo-electron microscopy (EM) reveals a multivalent intasome-nucleosome interface involving both gyres of nucleosomal DNA and one H2A-H2B heterodimer. While the histone octamer remains intact, the DNA is lifted from the surface of the H2A-H2B heterodimer to allow integration at strongly preferred superhelix location (SHL) ±3.5 positions. Amino acid substitutions disrupting these contacts impinge on the ability of the intasome to engage nucleosomes in vitro and redistribute viral integration sites on the genomic scale. Our findings elucidate the molecular basis for nucleosome capture by the viral DNA recombination machinery and the underlying nucleosome plasticity that allows integration. Genomic positions of integration sites of WT and mutant PFV vectors in HT1080 cells were determined using ligation-mediated PCR and next generation sequencing. Integration sites of purified recombinant PFV intasome into deproteinized human genomic DNA were used as a reference dataset.
2015-06-10 | E-GEOD-67730 | biostudies-arrayexpress
Project description:Induced pluripotent stem cell-derived human hepatocyte-like cells (iHeps) could provide a powerful tool for studying the mechanisms underlying human liver development and disease, testing the efficacy and safety of pharmaceuticals across different patients (i.e. personalized medicine), and enabling cell-based therapies in the clinic. However, current in vitro protocols that rely upon growth factors and extracellular matrices (ECM) alone yield iHeps with low levels of liver functions relative to adult primary human hepatocytes (PHHs). Moreover, these low hepatic functions in iHeps are difficult to maintain for prolonged times (weeks to months) in culture. Here, we engineered a micropatterned co-culture (iMPCC) platform in a multi-well format that, in contrast to conventional confluent cultures, significantly enhanced the functional maturation and longevity of iHeps in culture for 4 weeks in vitro when benchmarked against multiple donors of PHHs. In particular, iHeps were micropatterned onto collagen-coated domains of empirically optimized dimensions, surrounded by 3T3-J2 murine embryonic fibroblasts, and then sandwiched with a thin layer of ECM gel (Matrigel™). We assessed iHep maturity via global gene expression profiles, hepatic polarity, secretion of albumin and urea, basal CYP450 activities, phase-II conjugation, drug-mediated CYP450 induction, and drug-induced hepatotoxicity. Conclusion: Controlling both homotypic interactions between iHeps and heterotypic interactions with stromal fibroblasts significantly matures iHep functions and maintains them for several weeks in culture. In the future, iMPCCs could prove useful for drug screening, studying molecular mechanisms underlying iHep differentiation, modeling liver diseases, and integration into human-on-a-chip systems being designed to assess multi-organ responses to compounds. We used Affymetrix microarrays to profile the global gene expression of co-culture stabilized iHeps (iMPCCs) relative to freshly isolated and co-culture stabilized primary human hepatocytes (2 donors).
2015-02-01 | GSE62962 | GEO
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2016-05-17 | E-GEOD-81491 | biostudies-arrayexpress