Differentiation Of hiPSCs Research Articles

Generation and Functional Characterization of Monocytes and Macrophages Derived from Human Induced Pluripotent Stem Cells.

Monocytes and macrophages are essential for immune defense and tissue hemostasis. They are also the underlying trigger of many diseases. The availability of robust and short protocols to induce monocytes and macrophages from human induced pluripotent stem cells (hiPSCs) will benefit many applications of immune cells in biomedical research. Here, we describe a protocol to derive and functionally characterize these cells. Large numbers of hiPSC‐derived monocytes (hiPSC‐mono) could be generated in just 15 days. These monocytes were fully functional after cryopreservation and could be polarized to M1 and M2 macrophage subtypes. hiPSC‐derived macrophages (iPSDMs) showed high phagocytotic uptake of bacteria, apoptotic cells, and tumor cells. The protocol was effective across multiple hiPSC lines. In summary, we developed a robust protocol to generate hiPSC‐mono and iPSDMs which showed phenotypic features of macrophages and functional maturity in different bioassays. © 2020 The Authors. Basic Protocol 1: Differentiation of hiPSCs toward monocytes Support Protocol 1: Isolation and cryopreservation of monocytes Support Protocol 2: Characterization of monocytes Basic Protocol 2: Differentiation of different subtypes of macrophages Support Protocol 3: Characterization of hiPSC‐derived macrophages (iPSDMs) Support Protocol 4: Functional characterization of different subtypes of macrophages

Multi-lineage Human iPSC-Derived Platforms for Disease Modeling and Drug Discovery.

Human induced pluripotent stem cells (hiPSCs) provide a powerful platform for disease modeling and have unlocked new possibilities for understanding the mechanisms governing human biology, physiology, and genetics. However, hiPSC-derivatives have traditionally been utilized in two-dimensional monocultures, in contrast to the multi-systemic interactions that influence cells in the body. We will discuss recent advances in generating more complex hiPSC-based systems using three-dimensional organoids, tissue-engineering, microfluidic organ-chips, and humanized animal systems. While hiPSC differentiation still requires optimization, these next-generation multi-lineage technologies can augment the biomedical researcher's toolkit and enable more realistic models of human tissue function.

Inhibition of cardiomyocyte differentiation of human induced pluripotent stem cells by Ribavirin: Implication for its cardiac developmental toxicity

Ribavirin has been proven to be an antiviral treatment, whereas there are still risks of hemolysis and congenital malformation. Abnormal cardiac development contributes to the occurrence and development of many heart diseases. However, there is so far no evidence that ribavirin induces human cardiac developmental toxicity. Herein, we employed the cardiac differentiation model of human induced pluripotent stem cells (hiPSCs) to determine the impact of ribavirin on heart development. Our data showed that ribavirin at clinically high concentrations (5 and 10 μM) significantly inhibited the proliferation and differentiation of hiPSCs from mesoderm to cardiac progenitor cells and cardiac progenitor cells to cardiomyocytes, but not from pluripotent status to mesoderm. Meanwhile, DCFH-DA staining revealed that ribavirin could increase ROS content in the mid-phase of differentiation. In addition, ribavirin treatment (1, 5 and 10 μM) remarkably caused DNA damage which was shown by the increase of γH2AX-positive cells and upregulation of the p53 during the differentiation of hiPSCs from mesoderm to cardiac progenitor cells. Moreover, exposuring to ribavirin (5 and 10 μM) markedly upregulated the expression of lncRNAs Gas5 in both mid-phase and late phase of differentiation and HBL1 in the mid-phase. In conclusion, our results suggest that ribavirin is detrimental in cardiac differentiation of hiPSCs, which may be associated with DNA damage, upregulated p53 and increased Gas5. It may provide the evidence for the rational clinical application of ribavirin.

GATA4 Is Required for Budding Morphogenesis of Posterior Foregut Endoderm in a Model of Human Stomach Development

Three-dimensional gastrointestinal organoid culture systems provide innovative and tractable models to investigate fundamental developmental biology questions using human cells. The goal of this study was to explore the role of the zinc-finger containing transcription factor GATA4 in gastric development using an organoid-based model of human stomach development. Given GATA4′s vital role in the developing mouse gastrointestinal tract, we hypothesized that GATA4 plays an essential role in human stomach development. We generated a human induced pluripotent stem cell (hiPSC) line stably expressing an shRNA targeted against GATA4 (G4KD-hiPSCs) and used an established protocol for the directed differentiation of hiPSCs into stomach organoids. This in vitro model system, informed by studies in multiple non-human model systems, recapitulates the fundamental processes of stomach development, including foregut endoderm patterning, specification, and subsequent tissue morphogenesis and growth, to produce three-dimensional fundic or antral organoids containing functional gastric epithelial cell types. We confirmed that GATA4 depletion did not disrupt hiPSC differentiation to definitive endoderm (DE). However, when G4KD-hiPSC-derived DE cells were directed to differentiate toward budding SOX2+, HNF1B+ posterior foregut spheroids, we observed a striking decrease in the emergence of cell aggregates, with little to no spheroid formation and budding by GATA4-depleted hiPSCs. In contrast, control hiPSC-derived DE cells, expressing GATA4, formed aggregates and budded into spheroids as expected. These data support an essential role for GATA4 during the earliest stages of human stomach development.

ASCL1- and DLX2-induced GABAergic neurons from hiPSC-derived NPCs

BackgroundSomatic cell reprogramming is routinely used to generate donor-specific human induced pluripotent stem cells (hiPSCs) to facilitate studies of disease in a human context. The directed differentiation of hiPSCs can generate large quantities of patient-derived cells; however, such methodologies frequently yield heterogeneous populations of neurons and glia that require extended timelines to achieve electrophysiological maturity. More recently, transcription factor-based induction protocols have been show to rapidly generate defined neuronal populations from hiPSCs. New methodIn a manner similar to our previous adaption of NGN2-glutamatergic neuronal induction from hiPSC-derived neural progenitor cells (NPCs), we now adapt an established protocol of lentiviral overexpression of ASCL1 and DLX2 to hiPSC-NPCs. ResultsWe demonstrate induction of a robust and highly pure population of functional GABAergic neurons (iGANs). Importantly, we successfully applied this technique to hiPSC-NPCs derived from ten donors across two independent laboratories, finding it to be an efficient and highly reproducible approach to generate induced GABAergic neurons.Our results show that, like hiPSC-iGANs, NPC-iGANs exhibit increased GABAergic marker expression, electrophysiological maturity, and have distinct transcriptional profiles that distinguish them from other cell-types of the brain. Nonetheless, until donor-matched hiPSCs-iGANs and NPC-iGANs are directly compared, we cannot rule out the possibility that subtle differences in patterning or maturity may exist between these populations; one should always control for cell source in all iGAN experiments. ConclusionsThis methodology, relying upon an easily cultured starting population of hiPSC-NPCs, makes possible the generation of large-scale defined co-cultures of induced glutamatergic and GABAergic neurons for hiPSC-based disease models and precision drug screening.

3D Bioprinting Pluripotent Stem Cell Derived Neural Tissues Using a Novel Fibrin Bioink Containing Drug Releasing Microspheres.

3D bioprinting combines cells with a supportive bioink to fabricate multiscale, multi-cellular structures that imitate native tissues. Here, we demonstrate how our novel fibrin-based bioink formulation combined with drug releasing microspheres can serve as a tool for bioprinting tissues using human induced pluripotent stem cell (hiPSC)-derived neural progenitor cells (NPCs). Microspheres, small spherical particles that generate controlled drug release, promote hiPSC differentiation into dopaminergic neurons when used to deliver small molecules like guggulsterone. We used the microfluidics based RX1 bioprinter to generate domes with a 1 cm diameter consisting of our novel fibrin-based bioink containing guggulsterone microspheres and hiPSC-derived NPCs. The resulting tissues exhibited over 90% cellular viability 1 day post printing that then increased to 95% 7 days post printing. The bioprinted tissues expressed the early neuronal marker, TUJ1 and the early midbrain marker, Forkhead Box A2 (FOXA2) after 15 days of culture. These bioprinted neural tissues expressed TUJ1 (15 ± 1.3%), the dopamine marker, tyrosine hydroxylase (TH) (8 ± 1%) and other glial markers such as glial fibrillary acidic protein (GFAP) (15 ± 4%) and oligodendrocyte progenitor marker (O4) (4 ± 1%) after 30 days. Also, quantitative polymerase chain reaction (qPCR) analysis showed these bioprinted tissues expressed TUJ1, NURR1 (gene expressed in midbrain dopaminergic neurons), LMX1B, TH, and PAX6 after 30 days. In conclusion, we have demonstrated that using a microsphere-laden bioink to bioprint hiPSC-derived NPCs can promote the differentiation of neural tissue.

Application of a human mesoderm tissue elongation system in vitro derived from human induced pluripotent stem cells to risk assessment for teratogenic chemicals

Toxic compounds from the mother’s diet and medication in addition to genetic factors and infection during pregnancy remain risks for various congenital disorders and misbirth. To ensure the safety of food and drugs for pregnant women, establishment of an in vitro system that morphologically resembles human tissues has been long desired. In this study, we focused on dorsal mesoderm elongation, one of the critical early development events for trunk formation, and we established in vitro autonomous elongating tissues from human induced pluripotent stem cells (hiPSCs). This artificial tissue elongation is regulated by MYOSIN II and FGF signaling, and is diminished by methylmercury or retinoic acid (RA), similar to in vivo human developmental disabilities. Moreover, our method for differentiation of hiPSCs requires only a short culture period, and the elongation is cell number-independent. Therefore, our in vitro human tissue elongation system is a potential tool for risk assessment assays for identification of teratogenic chemicals via human tissue morphogenesis.

Multi-Dimensional Mapping of Cell States during Cardiomyocyte Differentiation using Live Imaging and RNA Fish

The Allen Institute for Cell Science is developing a state space of stem cell structural signatures to study changes in cellular organization of human induced pluripotent stem cells (hiPSCs) as they differentiate into cardiomyocytes. We have used CRISPR/Cas9 to generate a collection of ∼35 endogenous fluorescently tagged hiPSC lines (www.allencell.org), each expressing a monoallelic EGFP-tagged protein that localizes to a particular cellular structure or organelle. In addition, we have developed several pertinent methods: 1) scarless GFP-tagging of late expressing cardiomyocyte genes, including ACTN2, ssTNNI1, MYL2, MYL7 and TTN, to study the organization and morphogenesis of the contractile apparatus; 2) a robust protocol for differentiation of hiPSCs into cardiomyocytes and methods for preparing cells for imaging; and 3) image-based assays and segmentation algorithms that enable single-cell analyses of structure localization in differentiated cardiomyocytes. Using the cardiomyocyte-specific protein ACNT2 as a reference, we have also developed methods for quantifying the extent of sarcomeric organization in cells across timepoints, thus placing individual cells along a psuedotime axis based on their level of structural ACTN2 organization. We are also using this approach to analyze sarcomere maturation via other key sarcomeric structural and regulatory proteins. This permits us to use sarcomere organization state as a reference system to analyze the reorganization of cytoplasmic structures. We are now incorporating multiplexed fluorescence in situ hybridization (FISH) into this analysis, allowing us to directly investigate the connection between cell structure organization and gene expression profiles on a single-cell level and also to produce structure-referenced maps of RNA localization. This imaging pipeline is generating an image database of high-resolution, high-replicate image data of the fluorescently tagged structures with a goal of generating an integrated image “state space” of intracellular reorganization during cardiomyocyte differentiation.

Modulation of oxygen tension, acidosis, and cell density is crucial for neural differentiation of human induced pluripotent stem cells

Human induced pluripotent stem cell (hiPSC)-derived neural cells provide valuable disease models for pathophysiological analysis and drug discovery for intractable neurodegenerative diseases. However, neural differentiation of hiPSCs requires a complex and long culture procedure, which has been a bottleneck for analysis. We previously demonstrated rapid, efficient, and simple motor neuron differentiation from human pluripotent stem cells (hPSCs). Although optimization of the microenvironment for the differentiation of hPSCs has been considered to achieve more efficient differentiation, it has never been investigated in detail. Here, we demonstrated that three microenvironmental modifiers, oxygen (O2) tension, pH, and cell density, critically affect neural differentiation of hiPSCs. Hypoxia is known to be involved in neural development in vivo and to promote neural differentiation of PSCs. However, in this study, it caused significant cell death in aggregation culture of human embryoid bodies (hEBs) and negatively affected neural differentiation. Modulation of pH by optimized carbon dioxide (CO2) tension improved neural differentiation of hiPSCs, but mild acidosis caused by increased CO2 tension suppressed neural differentiation without cell death. Moreover, high-cell density culture resulted in prominent acidosis and cell death under hypoxic conditions, which synergistically suppressed neural differentiation of hiPSCs. These results suggest that optimization of the microenvironment via O2 tension, pH, and cell density enables more efficient neural differentiation of hiPSCs for the analysis of neurological diseases.

Encapsulation boosts islet-cell signature in differentiating human induced pluripotent stem cells via integrin signalling

Cell replacement therapies hold great therapeutic potential. Nevertheless, our knowledge of the mechanisms governing the developmental processes is limited, impeding the quality of differentiation protocols. Generating insulin-expressing cells in vitro is no exception, with the guided series of differentiation events producing heterogeneous cell populations that display mixed pancreatic islet phenotypes and immaturity. The achievement of terminal differentiation ultimately requires the in vivo transplantation of, usually, encapsulated cells. Here we show the impact of cell confinement on the pancreatic islet signature during the guided differentiation of alginate encapsulated human induced pluripotent stem cells (hiPSCs). Our results show that encapsulation improves differentiation by significantly reshaping the proteome landscape of the cells towards an islet-like signature. Pathway analysis is suggestive of integrins transducing the encapsulation effect into intracellular signalling cascades promoting differentiation. These analyses provide a molecular framework for understanding the confinement effects on hiPSCs differentiation while confirming its importance for this process.

Thermosensitive hydrogels loaded with human-induced pluripotent stem cells overexpressing growth differentiation factor-5 ameliorate intervertebral disc degeneration in rats.

To evaluate the effects of thermosensitive hydrogels loaded with human-induced pluripotent stem cells transfected with the growth differentiation factor-5 (GDF5-hiPSCs) on rat intervertebral disc regeneration. GDF5-hiPSCs were cocultured with rat nucleus pulposus (NP) cells in vitro. Real-time PCR and western blot were used to determine the differentiation of hiPSCs. Rat caudal intervertebral discs were punctured using a needle under X-ray, and groups of coccygeal (Co) discs were subject to various treatments: Puncture group (Co6/7, punctured without treatment); Hydrogel group (Co7/8, 2 μl of hydrogel injected without cells); GDF5-hiPSCs + Hydrogel group (Co8/9, 2 μl of GDF5-hiPSCs-loaded hydrogel injected); and Normal control (Co5/6). X-ray, MRI, and histological evaluations were performed at 1, 2, and 3 months after cell transplantation and relative changes in the disc height index (DHI%) and voxel count were calculated and compared. GDF5-hiPSCs were successfully differentiated to a chondrogenic linage after cocultured with rat NP cells. In terms of X-ray, MRI, and HE staining scores, the GDF5-hiPSCs + Hydrogel group was significantly superior to the Puncture and Hydrogel groups (p < .05). Compared with the Normal group, the MRI-based voxel count of the GDF5-hiPSCs + Hydrogel group was significantly lower at 1, 2, and 3 months after cell transplantation (p < .05). However, there were no significant differences in histological scores at 1 and 2 months after cell transplantation compared with the Normal group (p > .05). In conclusion, thermosensitive hydrogel-encapsulated hiPSCs overexpressing the GDF5 gene ameliorated intervertebral disc degeneration.

Production of Innervated Skeletal Muscle Fibers Using Human Induced Pluripotent Stem Cells.

Only a limited number of large-scale protocols describe the production of mature skeletal muscle fibers from human induced pluripotent stem cells (hiPSCs). Here we describe a novel procedure for simultaneous differentiation of hiPSC into muscle cells and motor neurons, that generates innervated and contractile multinucleated skeletal muscle fibers with sarcomeric organization. Our protocol permits the production of expandable skeletal muscle progenitor cells and mature skeletal muscle fibers that can be used for the exploration of skeletal muscle differentiation for basic research, disease modeling, and drug discovery.

Differentiation of Human Induced Pluripotent Stem Cells (hiPSCs) into Osteoclasts

Defects in bone resorption by osteoclasts result in numerous rare genetic bone disorders as well as in some common diseases such as osteoporosis or osteopetrosis. The use of hiPSC-differentiated osteoclasts opens new avenues in this research field by providing an unlimited cell source and overcoming obstacles such as unavailability of human specimens and suitable animal models. Generation of hiPSCs is well established but efficient differentiation of hiPSCs into osteoclasts has been challenging. Published hiPSC-osteoclast differentiation protocols use a hiPSC-OP9 co-culture system or hiPSC-derived embryoid bodies (EBs) with multiple cytokines. Our three-stage protocol consists of 1) EB mesoderm differentiation, 2) expansion of myelomonocytic cells and 3) maturation of hiPSC-osteoclasts. We generate uniformly-sized EBs by culturing Accutase-dissociated hiPSCs on Nunclon Sphera microplates and promote EB mesoderm differentiation in a cytokine cocktail for 4 days. For Stage 2, EBs are transferred to gelatin-coated plates and cultured with hM-CSF and hIL-3 to expand the myelomonocytic population. By supplementing with vitamin D, hTGFβ, hM-CSF and hRANKL, cells collected at the end of Stage 2 are differentiated into mature osteoclasts (Stage 3). Compared to other techniques, our protocol does not require a co-culture system; induces EBs into mesoderm differentiation in a homogenous manner; uses less cytokines for differentiation; requires only a short time for osteoclast maturation and produces sufficient numbers of osteoclasts for subsequent molecular analyses. Graphic abstract.

Neural In Vitro Models for Studying Substances Acting on the Central Nervous System.

Animal models have been greatly contributing to our understanding of physiology, mechanisms of diseases, and toxicity. Yet, their limitations due to, e.g., interspecies variation are reflected in the high number of drug attrition rates, especially in central nervous system (CNS) diseases. Therefore, human-based neural in vitro models for studying safety and efficacy of substances acting on the CNS are needed. Human iPSC-derived cells offer such a platform with the unique advantage of reproducing the "human context" in vitro by preserving the genetic and molecular phenotype of their donors. Guiding the differentiation of hiPSC into cells of the nervous system and combining them in a 2D or 3D format allows to obtain complex models suitable for investigating neurotoxicity or brain-related diseases with patient-derived cells. This chapter will give an overview over stem cell-based human 2D neuronal and mixed neuronal/astrocyte models, in vitro cultures of microglia, as well as CNS disease models and considers new developments in the field, more specifically the use of brain organoids and 3D bioprinted in vitro models for safety and efficacy evaluation.

Increased mesodermal and mesendodermal populations by BMP4 treatment facilitates human iPSC line differentiation into a cardiac lineage

Human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) have attracted attention as a novel tool for drug safety screening and several differentiation protocols of hiPSC lines into cardiomyocytes have been reported; the standardization of these protocols will expand their applications for safety assessments such as "clinical safety trial-on-dish". Bone morphogenetic protein 4 (BMP4) is an important factor in promoting mesoderm differentiation and BMP4 treatment has been used at the early stage of cardiac differentiation into different hiPSCs. In the present study, we evaluated the effects of BMP4 treatment at the early stage of cardiac differentiation. We performed gene expression profiling of the germ layer during mesoderm differentiation of hiPSCs derived from three different donors. The expression of T (a mesoderm marker) and GATA6 (an endoderm marker) increased and that of PAX6 (a neuroectoderm marker) decreased in pooled embryoid bodies (EBs) after BMP4 treatment. Single-cell gene expression analysis revealed that mesodermal and mesendodermal populations increased in EBs derived from 253G1. Finally, BMP4 treatment increased mesodermal and mesendodermal populations compared with that without BMP4 in two other hiPSC lines, confirming the reproducibility of multiple hiPSC lines. Thus, our results suggest that BMP4 treatment increases mesodermal and mesendodermal populations at the early stage of cardiac differentiation in different hiPSC lines.

Metabolomic profiling during the differentiation of human induced pluripotent stem cells into hepatocyte-like cells

Human induced pluripotent stem cells (hiPSCs) are potentially an invaluable source of cells for regenerative medicine, disease modeling and drug discovery. However, the differentiation of hiPSCs into fully functional hepatocytes remains a major challenge. Despite the importance of the information carried by metabolomes, the exploitation of metabolomics for characterizing and understanding hiPSC differentiation remains largely unexplored. Here, to increase knowledge of hiPSC maturation into mature hepatocytes, we investigated their metabolomics profiles during sequential step-by-step differentiation: definitive endoderm (DE), specification into hepatocytes (HB-pro (hepatoblast progenitors)), progenitor hepatocytes (Pro-HEP) and mature hepatocyte-like cells (HLCs). Metabolomics analysis illustrated a switch from glycolysis-based respiration in DE step to oxidative phosphorylation in HLCs step. DE was characterized by fatty acid beta oxidation, sorbitol metabolism and pentose phosphate pathway, and glutamine and glucose metabolisms as various potential energy sources. The complex lipid metabolism switch was monitored via the reduction of lipid production from DE to HLCs step, whereas high glycerol production occurred mainly in HLCs. The nitrogen cycle, via urea production, was also a typical mechanism revealed in HLCs step. Our analysis may contribute to better understanding of differentiation and suggest new targets for improving iPSC maturation into functional hepatocytes.

Generation of a NKX2.1 - p63 double transgenic knock-in reporter cell line from human induced pluripotent stem cells (MHHi006-A-4).

Tumor protein p63 (p63) encodes for a transcription factor of the p53 family and is a marker for respiratory basal cells. Based on a NKX2.1 knock-in reporter cell line from human induced pluripotent stem cells (hiPSCs) (MHHi06-A-2) we established a NKX2.1/p63 double transgenic knock-in reporter cell line using TALEN technology. The reporter enables the optimization and monitoring of hiPSC differentiation towards NKX2.1/p63 double positive cells as well as enrichment for single or double positive cells.

Electrospun silk nanofibers improve differentiation potential of human induced pluripotent stem cells to insulin producing cells.

With regard to lifestyle and diet, one of the problems that threaten mankind is diabetes. Given the lack of responsiveness to available drug therapies, the advances made in recent decades in tissue engineering and cell therapy have created a great deal of hope for the treatment of this disease. In this study, silk nanofibrous scaffold (3D) was fabricated by electrospinning and then its biocompatibility and non-toxicity by MTT assay. After that, scaffold supportive effects on human induced pluripotent stem cells (hiPSCs) differentiation to insulin producing cells (IPCs) was studied at the gene and protein levels. IPCs related genes and proteins were up regulated in electrospun silk group significantly greater than tissue culture plates group (2D). In addition, another part of the results demonstrated that differentiated cells on 2D and 3D groups have great functional properties including C-peptide and insulin secreting. It can be concluded that silk nanofibers has a great potential for use in pancreatic tissue engineering applications by support viability, growth and IPCs differentiation of iPSCs.

P2571Differentiation of iPS-derived cardiac mesoderm cells into cardiomyocytes using inducible shRNA technology

Abstract Introduction The development of robust and scalable cardiomyocyte differentiation protocols from human pluripotent stem cells (hPSCs) offers the opportunity to derive large number of autologous cardiomyocytes for cell therapy. However, human induced pluripotent stem cells-derived cardiomyocytes (hiPSCs-CM) do not proliferate, are susceptible to ischemia and poorly retained in the recipient myocardium. In addition, arrhythmias are a severe side effect of cell therapy with hiPSC-CM, probably due to their immature phenotype. Based on previous observations in our lab, we speculate that the heart environment might be an important factor to enable full maturation and in situ coupling of the implanted cells in vivo. We therefore speculate that transplantation of robust, proliferative, partially committed, non-tumorigenic cardiac mesoderm cells and subsequent differentiation in situ may overcome these limitations. Purpose We seek to engineer hiPSC-derived cardiac mesoderm cells for implantation in the failing myocardium that, once they have settled, consolidated, and proliferated in situ, can be selectively induced to mature into cardiomyocytes. Methods Wnt signalling induces mesoderm lineage differentiation of hiPSCs and inhibits further maturation towards CM. To induce Wnt signalling inhibition, we designed a customized biomimetic shRNA targeting the Wnt agonist β-catenin fused to a fluorescent reported protein controlled by a Tet-ON promoter. This transgene was transferred to the safe harbour locus AAVS1 of the OPTI-OX hiPS cell line constitutively expressing the reverse tetracycline transactivator protein (rtTA) in the ROSA26 locus. In this configuration, gene expression can be activated in trans upon doxycycline administration. Results We studied the kinetics of gene expression activation on the engineered undifferentiated hiPSCs and observed that a maximal reduction of 80–90% β-catenin correlating with reporter expression was achieved upon a 4-day treatment with doxycycline. Importantly, this activation could be fully reverted 6 days upon withdrawal. Furthermore, in vitro differentiation of cardiac mesoderm cells into cardiomyocytes was enhanced upon doxycycline administration as compared to the untreated cells as assessed by the upregulation of cardiomyocyte specific genes and the increased percentage of cTNT+ cells. Conclusion An inducible system for targeted β-catenin downregulation by shRNA allows for significant, sustained, and reversible Wnt signalling modulation, which is sufficient to induce cardiomyocyte differentiation of cardiac mesoderm cells in vitro. This technology may be implemented to differentiate the transplanted cells in the failing myocardium, opening new prospects to overcome the current limitations of hiPSC-based cardiac cell therapy. Acknowledgement/Funding BMBF funding (FKZ 13GW0098, FKZ 13GW0099) DFG funding through the BSRT GSC 203

Integration of metabolomic and transcriptomic profiling to compare two protocols of differentiation of human induced pluripotent stem cells into hepatocytes

Human hepatocyte-like cells derived from human induced pluripotent stem cells (hiPSC) may provide an unlimited supply of cells for in vitro liver models. However, hiPSC differentiation remains a major challenge due to immaturity of the hepatocytes obtained and the high cost of differentiation protocols currently proposed. Here, we studied the efficacy of new protocol, with reduction of growth factors, for the generation of hepatocyte-like cells from hiPSC. We performed metabolomic and mRNA analysis by RTqPCR and nanoCAGE processing to identify and understand key metabolisms during differentiation. By reducing the change frequency of the culture medium in the new protocol, we successfully generated hepatocyte-like cells producing albumin, urea, and CYP3A4 positive. The metabolomic analysis successfully extracted both signatures, common and specific, for each differentiation step. Integrating the metabolomic data with transcriptomic contributed to explaining the kinetics of carbohydrate, lipid and nitrogen metabolism throughout differentiation. The information extracted during differentiation showed that the cells moved from an aerobic-like respiration pattern to a mitochondrial oxidative respiration pattern in both protocols. Reducing culture medium renewal led to reduced glucose consumption, followed by fructose production and significant extracellular lipogenesis throughout differentiation. We believe that the overall dataset can provide information on the sequence of process.