Enhancing the Functional Maturity of iPSC-Derived Human Hepatocytes Via Controlled Presentation of Cell-Cell Interactions In Vitro
ABSTRACT: 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.
Project description:Direct induction of induced hepatocytes (iHeps) from fibroblasts holds potential as a strategy for regenerative medicine, but until now has only been shown in culture settings. Here, we describe in vivo iHep formation using transcription factor induction and genetic fate tracing in mouse models of chronic liver disease. We show that ectopic expression of the transcription factors FOXA3, GATA4, HNF1A and HNF4A from a polycistronic lentiviral vector converts mouse myofibroblasts into cells with a hepatocyte phenotype. In vivo expression of the same set of transcription factors from a p75 neurotrophin receptor peptide (p75NTRp)-tagged adenovirus enabled the generation of hepatocyte-like cells from myofibroblasts in fibrotic mouse livers and reduced liver fibrosis. We have therefore been able to convert profibrogenic myofibroblasts in the liver into hepatocyte-like cells with positive functional benefits. This direct in vivo reprogramming approach may open new avenues for the treatment of chronic liver disease. Whole Mouse Genome Oligo Microarray v2 (4x44K) (Agilent Technologies) was used to characterize global gene expression profiles of iHeps compared to myofibroblasts and primary mouse hepatocytes. All microarrays were performed at the Research Core Unit Transcriptomics of the Hanover Medical School. Briefly, total RNA was used to prepare the aminoallyl-UTPmodified (aaUTP) cRNAs (Amino Allyl MessageAmp™ II Kit; #AM1753; Life Technologies) as directed by the company. The aaUTP-cRNAs were labelled with Alexa Fluor 555 Reactive Dye (#A32756; LifeTechnologies). Prior to the reverse transcription reaction, 1μl of a 1:5000 dilution of Agilent’s One-Color spike-in Kit stock solution (#5188-5282, Agilent Technologies) was added to 100ng of total RNA of each analyzed sample. The cRNA fragmentation, hybridization, and washing steps were carried out according to Agilent’s One-Color Microarray-Based Gene Expression Analysis Protocol V5.7 except that 500ng of each labelled cRNA sample were used for hybridization. Slides were scanned on the Agilent Micro Array Scanner G2565 CA (pixel resolution 5 μm, bit depth 20). Data extraction was performed with the Feature Extraction Software V10.7.3.1. 12 samples were analyzed: Pr-mHSC: Primary myofibroblasts derived from hepatic stellate cells (HSCs), 2 replicates; In-vivo iHep: In-vivo myofibroblasts-derived from induced hepatocytes (iHep), 3 replicates; In-vivo eHep: In-vivo endogenous hepatocytes (eHep), 3 replicates; In-vitro iHep: In-vitro myofibroblasts-derived from induced hepatocytes (iHep), 3 replicates; PH24h: Primary hepatocytes (PH) cultured for 24 hours, 1 replicate.
Project description:We developed in vivo reprogramming of myofibroblasts (MFs) into induced hepatocytes (MF-iHeps) using adeno-associated virus serotype 6 (AAV6) vectors expressing hepatic transcription factors in MF fate tracing (Lrat-Cre;R26R-ZsGreen) mice with carbon tetrachloride (CCl4)-induced liver fibrosis. To determine whether MF-iHeps acquire full hepatocyte differentiation, we used microarrays to profile their global gene expression. We isolated MF-iHeps and primary hepatocytes (Heps) from the same mice by laser-capture microdissection (5 and 3 biological replicates, respectively) and hepatic MFs from CCl4-treated littermates isolated by fluorescence-activated cell sorting (3 biological replicates). Total RNA was extracted, transcribed, amplified and biotin labeled. Labeled cDNA targets were hybridized to GeneChip Mouse Gene 1.0 ST arrays (Affymetrix).
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.
Project description:Plasticity of differentiated cells has been proved by nuclear transfer, induced pluripotent cells and transdifferentiation. Here we show that by transduction of 3 factors (Hnf1alpha, Gata4, and Foxa3) and p19Arf inactivation, tail-tip fibroblasts can be converted to hepatocyte-like (iHep) cells, expressing hepatocyte marker genes, and acquiring many mature hepatocyte functions in vitro and in vivo. Overall design: p19Arf-null TTFs were tranfected with 3 liver enriched transcription factors, then changed to modified Block's medium. To enrich iHep cells, epithelial cells were enriched by partial trypsin digestion.
Project description:To clarify the gene expression profile of iHep, microarray analysis was performed using iHeps induced by 10 TFs (Foxg1, Lcor, Hnf3b, Hnf4a, Foxo6, Cdx2, Tcf1, Foxa3 ,Tcf2, Onecut1) and 9 TFs (Onecut1 was omitted from 10 TFs). Unsupervised hierarchical clustering indicated that iHep is expressing a global transcriptional profile more similar to that of HPCs rather than that of NPCs, and suggested that TFs present in the pool acted as inducing TFs. HPC (HB1 and HNG2) were established from fetal liver (E13.5) of C57BL6J and STOCK Tg(Nanog-GFP, Puro)1 Yam, respectively. iHeps were induced from NPC (NSBAg2, established from an ES cell line BAg73C2 carrying beta-geo knock-in allele in Afp) using retroviral vectors (pMXs without drug-selection markers) of 9 or 10 transcription factors. Three weeks after the infection, G418 was added and cultured for 1 week before the harvest. NSBAg2 and NSEB5-2C were used for the data of NPC. GSM396240 and GSM336010 were used for the data of ESC.
Project description:Plasticity of differentiated cells has been proved by nuclear transfer, induced pluripotent cells and transdifferentiation. Here we show that by transduction of 3 factors (Hnf1alpha, Gata4, and Foxa3) and p19Arf inactivation, tail-tip fibroblasts can be converted to hepatocyte-like (iHep) cells, expressing hepatocyte marker genes, and acquiring many mature hepatocyte functions in vitro and in vivo. p19Arf-null TTFs were tranfected with 3 liver enriched transcription factors, then changed to modified Block's medium. To enrich iHep cells, epithelial cells were enriched by partial trypsin digestion.
Project description:The study recapitulates, through in vitro micropatterned co-cultures, interactions between HIV-infected T-lymphocytes and intestinal epithelial cells in order to investigate the mechanisms underlying the disruption of normal epithelial cell and barrier function during HIV infection. The co-culture method simplifies observation/monitoring of the two cell types and is particularly suited for laser microdissection-based retrieval of the epithelial cells for downstream gene expressions studies. Microarrays were used to characterize changes in gene expression in HT29 epithelial cells co-cultured with Jurkat T-lymphocytes in the presence and absence of HIV infection Micropatterned co-cultures were generated of healthy or HIV-infected T-lymphocytes (Jurkat) and human intestinal epithelial (HT-29) cells whereby both cell types were positioned on the same surface in a price spatial configuration (micropattern). HT29 celsl were then isolated by laser capture microdissection and used for RNA extraction and hybridization on Affymetrix U133 Plus2 microarrays.
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, Hnf4α 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
Project description:Human skin-derived precursor cells (hSKP) are a post natal stem cell population isolated from the dermis. These cells acquire hepatic characteristics upon differentiation with hepatogenic factors. Differentiated hSKP show characteristics of hepatocyte precursor cells and respond to hepatotoxic compounds in a comparable way as human hepatocyte cultures. We used microarray analyses to evaluate the modulation of gene expression due to exposure to a steatosis-inducing compound. hSKP obtained from 3 different donors were firstly differentiated and cultivated in the presence or absence of sodium valproate (Na-VPA). Control and Na-VPA samples were collected after 24h exposure.
Project description:Hepatocyte-like cells differentiated from human iPS cells are expected to be utilized in pharmaceutical research and regenerative medicine. Recently, various culture methods for human iPS cell maintenance have been developed. However, it is not well known whether human iPS cell maintenance method affects hepatic differentiation potency. In this study, we cultured human iPS cells using four maintenance methods: ReproStem medium with feeder cells (mouse embryonic fibroblasts), AK02N medium with iMatrix-511 (E8 fragments of laminin511), Essential 8 medium with Vitronectin N (N-terminal domain of vitronectin), TeSR-E8 medium with Vitronectin XF (xeno-free vitronectin). Then, these human iPS cells were differentiated into the hepatocyte-like cells. Interestingly, the gene expression levels of definitive endoderm markers in the definitive endoderm cells generated from human iPS cells cultured with ReproStem or TeSR-E8 medium were higher than those in other groups. The gene expression level of foregut marker, HHEX, in the definitive endoderm cells generated from human iPS cells cultured with ReproStem medium was higher than that in other groups. Consistently, the expression levels of hepatocyte markers, albumin and urea secretion capacity, and CYP3A4 activity in the hepatocyte-like cells generated from human iPS cells cultured with ReproStem medium were higher than those in other groups. Our data indicated that the most suitable human iPS cell maintenance method for efficient hepatic differentiation was the on-feeder method which uses mouse embryonic fibroblasts, but not feeder-free methods. In conclusion, human iPS cell maintenance method largely affects hepatic differentiation potency. Overall design: The human iPS cell line, YOW-iPS was maintained by one of four different culture methods (Repro, AK02N, E8, and TeSR-E8 method). Repro, AK02N, E8, and TeSR-E8 were pooled from triplicate samples of one independent experiments, and then microarray analysis was performed.