Jürgen Hescheler

University of Cologne, Köln, North Rhine-Westphalia, Germany

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Publications (511)2223.99 Total impact

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    ABSTRACT: Traditional Chinese herbal medicines (TCMs) have been widely used against a broad spectrum of biological activities, including influencing the cardiac differentiation from mouse embryonic stem cells (mESCs). However, their effects and mechanisms of action on ESCs proliferation remain to be determined. The present study aimed to determine the effect of three TCMs, baicalin, ginsenoside Rg1, and puerarin, on mESCs proliferation and to elucidate the possible mechanism of their action. Cell proliferation was examined with a cell proliferation assay Cell Counting Kit-8 (CCK-8), propidium iodide (PI) staining was used to visualize cell cycle. The mRNA expression level of c-myc, c-fos, c-jun, GAPDH and microRNAs were measured by quantitative real time RT-PCR. We found that baicalin 50 μM suppressed the proliferation of mESCs as observations in more cells in G1 phase and less cells in either S phase or G2/M phase. Moreover, baicalin suppressed the expressions of c-jun and c-fos in mESCs and down-regulated the expression of miR-294. Overexpression of miR-294 in mESCs significantly reversed the effects of baicalin both on mESC proliferation and c-fos/c-jun expression. Baicalin down-regulation of miR-294 may be its key mechanism of action in decreasing mESCs proliferation. © 2015 S. Karger AG, Basel.
    Cellular Physiology and Biochemistry 03/2015; 35(5):1868-1876. DOI:10.1159/000373997 · 3.55 Impact Factor
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    ABSTRACT: Voltage-gated calcium channels (VGCCs) represent a key link between electrical signals and non-electrical processes, such as contraction, secretion and transcription. Evolved to achieve high rates of Ca(2+)-selective flux, they possess an elaborate mechanism to select for Ca(2+) over foreign ions. It has been convincingly linked to competitive binding in the pore, but the fundamental question how this is reconcilable with high rates of Ca(2+) transfer remains unanswered. By virtue of their similarity to Ca(2+), polyvalent cations can interfere with the function of VGCCs and have proven instrumental in probing the mechanisms underlying selective permeation. Recent emergence of crystallographic data on a set of Ca(2+)-selective model channels provides a structural framework for permeation in VGCCs, and warrants a reconsideration of their diverse modulation by polyvalent cations, which can be roughly separated into three general mechanisms: (I) Long-range interactions with charged regions on the surface, affecting the local potential sensed by the channel or influencing voltage-sensor movement by repulsive forces (electrostatic effects), (II) short-range interactions with sites in the ion-conducting pathway, leading to physical obstruction of the channel (pore block), and in some cases (III) short-range interactions with extracellular binding sites, leading to non-electrostatic modifications of channel gating (allosteric effects). These effects and the underlying molecular mechanisms provide valuable insights into the function of VGCCs, and have important physiological and pathophysiological implications. Allosteric suppression of certain of the pore-forming Cavα1-subunits (Cav2.3, Cav3.2) by Zn(2+) and Cu(2+) may play a major role for the regulation of excitability by endogenous transition metal ions. The fact that these ions can often traverse VGCCs can contribute to the detrimental intracellular accumulation of metal ions following excessive release of endogenous Cu(2+) and Zn(2+) or exposure to non-physiological toxic metal ions. Copyright © 2015. Published by Elsevier Ltd.
    Progress in Neurobiology 03/2015; DOI:10.1016/j.pneurobio.2014.12.003 · 10.30 Impact Factor
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    ABSTRACT: Supplementation with Docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid (n-3 PUFA), has been becoming popular recently to ameliorate depression; however the molecular mechanism of DHA action remains unclear. The objective of this study is to investigate the mechanism underling the antidepressant effect of DHA by evaluating Gsα localization in lipid raft and the activity of adenylate cyclase in an in vitro glioma cell model.
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    ABSTRACT: Introduction: Innovations in human pluripotent stem cell research and their application in therapeutics have seen a giant leap in the past decade. Patent applications related to human pluripotent stem cell generation, culture and differentiation show an ever-increasing trend worldwide with hundreds of patents being applied for every year. With the turn of the second decade in stem cell patenting, a review of the latest patents issued will be significant. Areas covered: The growing need in healthcare sector has revolutionized stem cell application in clinical therapeutics by extending in unprecedented dimensions. With the potential of being able to differentiate into any desired adult cell lineage, human pluripotent stem cells find a wide range of applicability in clinical as well as cosmetic therapy. Moreover, the recent innovation of isolating a disease-specific pluripotent stem cell has opened new horizons to stem cell application in cell therapy. This review gives an overview of significant international patents granted on innovations in human pluripotent stem cell differentiation methodologies between 2009 and 2014. Expert opinion: The discovery of human pluripotent stem cells and their immense potential in clinical therapeutics has increasingly channeled scientific research in their orientation. Although being widely used to fathom human physiology, the trend in stem cell application is slowly shifting toward disease-modeling, drug safety evaluation and toxicity-testing. And in order to probe those unexplored realms of stem cell applications, a unified approach from the scientific community is imperative.
    Expert Opinion on Therapeutic Patents 03/2015; DOI:10.1517/13543776.2015.1021334 · 3.44 Impact Factor
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    ABSTRACT: The quintessential property of developing cardiomyocytes is their ability to beat spontaneously. The mechanisms underlying spontaneous beating in developing cardiomyocytes are thought to resemble those of adult heart, but have not been directly tested. Contributions of sarcoplasmic and mitochondrial Ca(2+)-signaling vs. If-channel in initiating spontaneous beating were tested in human induced Pluripotent Stem cell-derived cardiomyocytes (hiPS-CM) and rat Neonatal cardiomyocytes (rN-CM). Whole-cell and perforated-patch voltage-clamping and 2-D confocal imaging showed: (1) both cell types beat spontaneously (60-140/min, at 24°C); (2) holding potentials between -70 and 0mV had no significant effects on spontaneous pacing, but suppressed action potential formation; (3) spontaneous pacing at -50mV activated cytosolic Ca(2+)-transients, accompanied by in-phase inward current oscillations that were suppressed by Na(+)-Ca(2+)-exchanger (NCX)- and ryanodine receptor (RyR2)-blockers, but not by Ca(2+)- and If-channels blockers; (4) spreading fluorescence images of cytosolic Ca(2+)-transients emanated repeatedly from preferred central cellular locations during spontaneous beating; (5) mitochondrial un-coupler, FCCP at non-depolarizing concentrations (∼50nM), reversibly suppressed spontaneous pacing; (6) genetically encoded mitochondrial Ca(2+)-biosensor (mitycam-E31Q) detected regionally diverse, and FCCP-sensitive mitochondrial Ca(2+)-uptake and release signals activating during INCX oscillations; (7) If-channel was absent in rN-CM, but activated only negative to -80mV in hiPS-CM; nevertheless blockers of If-channel failed to alter spontaneous pacing. Copyright © 2015. Published by Elsevier Ltd.
    Cell Calcium 02/2015; DOI:10.1016/j.ceca.2015.02.003 · 4.21 Impact Factor
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    ABSTRACT: Industrial sectors perform toxicological assessments of their potential products to ensure human safety and to fulfil regulatory requirements. These assessments often involve animal testing but ethical, cost and time concerns, together with a ban on it in specific sectors, make appropriate in vitro systems indispensable in toxicology. Here, we summarize the outcome of an EPAA (European Partnership of Alternatives to Animal Testing)-organized workshop on the use of stem cell derived (SCD)-systems in toxicology, with a focus on industrial applications. SCD-systems, in particular iPSC-derived, provide physiological cell culture systems of easy access and amenable to a variety of assays. They also present the opportunity to apply the vast repository of existing non-clinical data for the understanding of in vitro to in vivo translation. SCD-systems from several toxicologically relevant tissues exist; they generally recapitulate many aspects of physiology and respond to toxicological and pharmacological interventions. However, focused research is necessary to accelerate implementation of SCD-systems in an industrial setting and subsequent use of such systems by regulatory authorities. Research is required into the phenotypic characterization of the systems, since methods and protocols for generating terminally differentiated SCD-cells are still lacking. Organotypical, 3D-culture systems in bioreactors and microscale tissue engineering technologies should be fostered, as they promote and maintain differentiation and support co-culture systems. They need further development and validation for their successful implementation in toxicity testing in industry. Analytical measures also need to be implemented to enable compound exposure and metabolism measurements for in vitro to in vivo extrapolation. The future of SCD-toxicological tests will combine advanced cell culture technologies and biokinetic measurements to support regulatory and research applications. However, scientific and technical hurdles must be overcome before SCD-in vitro methods undergo appropriate validation and become accepted in the regulatory arena.
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    ABSTRACT: Erythrina senegalensis DC (Fabaceae) bark is commonly used in sub-Saharan traditional medicine for the treatment of many diseases including gastrointestinal disorders and cardiovascular diseases. In this study, we investigated the effect of the aqueous extract of the stem bark of Erythrina senegalensis on the contractile properties of mouse ventricular slices and human induced pluripotent stem (hiPS) cell-derived cardiomyocytes. We also investigated the cytotoxic effect of the extract on mouse embryonic stem (ES) cells differentiating into cardiomyocytes (CMs).
    Journal of Ethnopharmacology 02/2015; 165. DOI:10.1016/j.jep.2015.02.002 · 2.94 Impact Factor
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    Dataset: cvs350supp
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    ABSTRACT: Several in-vivo heart developmental models have been applied to decipher the cardiac developmental patterning encompassing early, dorsal, cardiac and visceral mesoderm as well as various transcription factors such as Gata, Hand, Tin, Dpp, Pnr. The expression of cardiac specific transcription factors, such as Gata4, Tbx5, Tbx20, Tbx2, Tbx3, Mef2c, Hey1 and Hand1 are of fundamental significance for the in-vivo cardiac development. Not only the transcription factors, but also the signaling molecules involved in cardiac development were conserved among various species. Enrichment of the bone morphogenic proteins (BMPs) in the anterior lateral plate mesoderm is essential for the initiation of myocardial differentiation and the cardiac developmental process. Moreover, the expression of a number of cardiac transcription factors and structural genes initiate cardiac differentiation in the medial mesoderm. Other signaling molecules such as TGF-beta, IGF-1/2 and the fibroblast growth factor (FGF) play a significant role in cardiac repair/regeneration, ventricular heart development and specification of early cardiac mesoderm, respectively. The role of the Wnt signaling in cardiac development is still controversial discussed, as in-vitro results differ dramatically in relation to the animal models. Embryonic stem cells (ESC) were utilized as an important in-vitro model for the elucidation of the cardiac developmental processes since they can be easily manipulated by numerous signaling molecules, growth factors, small molecules and genetic manipulation. Finally, in the present review the dynamic role of the long noncoding RNA and miRNAs in the regulation of cardiac development are summarized and discussed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    International Journal of Cardiology 01/2015; 183C:117-128. DOI:10.1016/j.ijcard.2015.01.049 · 6.18 Impact Factor
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    ABSTRACT: Peptide-hormone secretion is partially triggered by Ca(2+) influx through voltage-gated Ca(2+) channels (VGCCs) and gene inactivation of Zn(2+)-sensitive Cav2.3-type VGCCs is associated with disturbed glucose homeostasis in mice. Zn(2+) has been implicated in pancreatic islet cell crosstalk and recent findings indicate that sudden cessation of Zn(2+) supply during hypoglycemia triggers glucagon secretion in rodents. Here we show that diethyldithiocarbamate (DEDTC), a chelating agent for Zn(2+) and other group IIB metal ions, differentially affects blood glucose and serum peptide hormone level in wild-type mice and mice lacking the Cav2.3-subunit. Fasting glucose and glucagon level were significantly higher in Cav2.3-deficient compared to wild-type mice, while DEDTC Zn(2+)-chelation produced a significant and correlated increase of blood glucose and serum glucagon concentration in wild-type but not Cav2.3-deficient mice. Glucose tolerance tests revealed severe glucose intolerance in Zn(2+)-depleted Cav2.3-deficient but not vehicle-treated Cav2.3-deficient or Zn(2+)-depleted wildtype mice. Collectively, these findings indicate that Cav2.3 channels are critically involved in the Zn(2+)-mediated suppression of glucagon secretion during hyperglycemia. Especially under conditions of Zn(2+) deficiency, ablation or dysfunction of Cav2.3 channels may lead to severe disturbances in glucose homeostasis. Copyright © 2015 Elsevier B.V. All rights reserved.
    Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 01/2015; 1853(5). DOI:10.1016/j.bbamcr.2015.01.001 · 5.30 Impact Factor
  • Zeitschrift für Gastroenterologie 01/2015; 53(01). DOI:10.1055/s-0034-1397089 · 1.67 Impact Factor
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    ABSTRACT: Modelling of cardiac development, physiology and pharmacology by differentiation of embryonic stem cells (ESCs) requires comparability of cardiac differentiation between different ESC lines. To investigate whether the outcome of cardiac differentiation is consistent between different ESC lines, we compared electrophysiological properties of ESC-derived cardiomyocytes (ESC-CMs) of different murine ESC lines. Two wild-type (D3 and R1) and two transgenic ESC lines (D3/aPIG44 and CGR8/AMPIGX-7) were differentiated under identical culture conditions. The transgenic cell lines expressed enhanced green fluorescent protein (eGFP) and puromycin-N-acetyltransferase under control of the cardiac specific α-myosin heavy chain (αMHC) promoter. Action potentials (APs) were recorded using sharp electrodes and multielectrode arrays in beating clusters of ESC-CMs. Spontaneous AP frequency and AP duration (APD) as well as maximal upstroke velocity differed markedly between unpurified CMs of the four ESC lines. APD heterogeneity was negligible in D3/aPIG44, moderate in D3 and R1 and extensive in CGR8/AMPIGX-7. Interspike intervals calculated from long-term recordings showed a high degree of variability within and between recordings in CGR8/AMPIGX-7, but not in D3/aPIG44. Purification of the αMHC+ population by puromycin treatment posed only minor changes to APD in D3/aPIG44, but significantly shortened APD in CGR8/AMPIGX-7. Electrophysiological properties of ESC-CMs are strongly cell line-dependent and can be influenced by purification of cardiomyocytes by antibiotic selection. Thus, conclusions on cardiac development, physiology and pharmacology derived from single stem cell lines have to be interpreted carefully. © 2015 S. Karger AG, Basel.
    Cellular Physiology and Biochemistry 01/2015; 35(1):305-14. DOI:10.1159/000369697 · 3.55 Impact Factor
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    ABSTRACT: The field of toxicogenomics (the application of '-omics' technologies to risk assessment of compound toxicities) has expanded in the last decade, partly driven by new legislation, aimed at reducing animal testing in chemical risk assessment but mainly as a result of a paradigm change in toxicology towards the use and integration of genome wide data. Many research groups worldwide have generated large amounts of such toxicogenomics data. However, there is no centralized repository for archiving and making these data and associated tools for their analysis easily available. The Data Infrastructure for Chemical Safety Assessment (diXa) is a robust and sustainable infrastructure storing toxicogenomics data. A central data warehouse is connected to a portal with links to chemical information and molecular and phenotype data. diXa is publicly available through a user-friendly web interface. New data can be readily deposited into diXa using guidelines and templates available online. Analysis descriptions and tools for interrogating the data are available via the diXa portal. Availability: http://www.dixa-fp7.eu CONTACT: d.hendrickx@maastrichtuniversity.nl ; info@dixa-fp7.eu SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online. © The Author(s) 2014. Published by Oxford University Press.
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    ABSTRACT: A long-term goal of numerous research projects is to identify biomarkers for in vitro systems predicting toxicity in vivo. Often, transcriptomics data are used to identify candidates for further evaluation. However, a systematic directory summarizing key features of chemically influenced genes in human hepatocytes is not yet available. To bridge this gap, we used the Open TG-GATES database with Affymetrix files of cultivated human hepatocytes incubated with chemicals, further sets of gene array data with hepatocytes from human donors generated in this study, and publicly available genome-wide datasets of human liver tissue from patients with non-alcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular cancer (HCC). After a curation procedure, expression data of 143 chemicals were included into a comprehensive biostatistical analysis. The results are summarized in the publicly available toxicotranscriptomics directory ( http://wiki.toxbank.net/toxicogenomics-map/ ) which provides information for all genes whether they are up- or downregulated by chemicals and, if yes, by which compounds. The directory also informs about the following key features of chemically influenced genes: (1) Stereotypical stress response. When chemicals induce strong expression alterations, this usually includes a complex but highly reproducible pattern named 'stereotypical response.' On the other hand, more specific expression responses exist that are induced only by individual compounds or small numbers of compounds. The directory differentiates if the gene is part of the stereotypical stress response or if it represents a more specific reaction. (2) Liver disease-associated genes. Approximately 20 % of the genes influenced by chemicals are up- or downregulated, also in liver disease. Liver disease genes deregulated in cirrhosis, HCC, and NASH that overlap with genes of the aforementioned stereotypical chemical stress response include CYP3A7, normally expressed in fetal liver; the phase II metabolizing enzyme SULT1C2; ALDH8A1, known to generate the ligand of RXR, one of the master regulators of gene expression in the liver; and several genes involved in normal liver functions: CPS1, PCK1, SLC2A2, CYP8B1, CYP4A11, ABCA8, and ADH4. (3) Unstable baseline genes. The process of isolating and the cultivation of hepatocytes was sufficient to induce some stress leading to alterations in the expression of genes, the so-called unstable baseline genes. (4) Biological function. Although more than 2,000 genes are transcriptionally influenced by chemicals, they can be assigned to a relatively small group of biological functions, including energy and lipid metabolism, inflammation and immune response, protein modification, endogenous and xenobiotic metabolism, cytoskeletal organization, stress response, and DNA repair. In conclusion, the introduced toxicotranscriptomics directory offers a basis for a rationale choice of candidate genes for biomarker evaluation studies and represents an easy to use source of background information on chemically influenced genes.
    Archives of Toxicology 11/2014; 88(12):2261-87. DOI:10.1007/s00204-014-1400-x · 5.08 Impact Factor
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    ABSTRACT: SEURAT-1 is a European public-private research consortium that is working towards animal-free testing of chemical compounds and the highest level of consumer protection. A research strategy was formulated based on the guiding principle to adopt a toxicological mode-of-action framework to describe how any substance may adversely affect human health.The proof of the initiative will be in demonstrating the applicability of the concepts on which SEURAT-1 is built on three levels:(i) Theoretical prototypes for adverse outcome pathways are formulated based on knowledge already available in the scientific literature on investigating the toxicological mode-of-actions leading to adverse outcomes (addressing mainly liver toxicity);(ii)adverse outcome pathway descriptions are used as a guide for the formulation of case studies to further elucidate the theoretical model and to develop integrated testing strategies for the prediction of certain toxicological effects (i.e., those related to the adverse outcome pathway descriptions);(iii) further case studies target the application of knowledge gained within SEURAT-1 in the context of safety assessment. The ultimate goal would be to perform ab initio predictions based on a complete understanding of toxicological mechanisms. In the near-term, it is more realistic that data from innovative testing methods will support read-across arguments. Both scenarios are addressed with case studies for improved safety assessment. A conceptual framework for a rational integrated assessment strategy emerged from designing the case studies and is discussed in the context of international developments focusing on alternative approaches for evaluating chemicals using the new 21st century tools for toxicity testing.
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    ABSTRACT: Stem cell-derived cardiomyocytes (CMs) are often electrophysiologically immature and heterogeneous, which represents a major barrier to their in vitro and in vivo application. Therefore, the purpose of this study was to examine whether Neuregulin-1b (NRG-1b) treatment could enhance in vitro generation of mature "working-type" CMs from induced pluripotent stem cells (iPS) and assessed the regenerative effects of these CMs on cardiac tissue following acute myocardial infarction (AMI). With that purpose, adult mouse fibroblast-derived iPS from α-MHC-GFP mice were derived and differentiated into CMs through NRG-1b and/or DMSO treatment. Cardiac specification and maturation of the iPS was analyzed by gene expression array, qRT-PCR, immunofluorescence, electron microscopy, and patch-clamp techniques. In vivo, the iPS-derived CMs or culture medium-control were injected into the peri-infarct region of hearts following coronary artery ligation, and functional and histology changes assessed from 1-8 weeks post-transplantation. Upon differentiation, the iPS displayed early and robust in vitro cardiogenesis, expressing cardiac-specific genes and proteins. More importantly, electrophysiological studies demonstrated that a more mature ventricular-like cardiac phenotype was achieved when cells were treated with NRG-1b and DMSO compared to DMSO alone. Furthermore, in vivo studies demonstrated that iPS-derived CMs were able to engraft and electromechanically couple to heart tissue, ultimately preserving cardiac function and inducing and adequate heart tissue remodeling. In conclusion, we have demonstrated that combined treatment with NRG-1b and DMSO leads to efficient differentiation of iPS into mature ventricular-like cardiac cells, which are capable of preserving cardiac function and tissue viability when transplanted into a mouse model of AMI.
    Stem Cells and Development 10/2014; DOI:10.1089/scd.2014.0211 · 4.20 Impact Factor
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    ABSTRACT: Voltage-gated Ca(2+) channels (VGCCs) are ubiquitous in excitable cells. These channels play key roles in many physiological events like cardiac regulation/pacemaker activity due to intracellular Ca(2+) transients. In the myocardium, the Cav1 subfamily (L-type: Cav1.2 and Cav1.3) is the main contributor to excitation-contraction coupling and/or pacemaking, whereas the Cav3 subfamily (T-type: Cav3.1 and Cav3.2) is important in rhythmically firing of the cardiac nodal cells. No established cardiac function has been attributed to the Cav2 family (E-/R-type: Cav2.3) despite accumulating evidence of cardiac dysregulation observed upon deletion of the Cav2.3 gene, the only member of this family so far detected in cardiomyocytes. In this review, we summarize the pathophysiological changes observed after ablation of the E-/R-type VGCC and propose a cardiac mechanism of action for this channel. Also, considering the role played by this channel in epilepsy and its reported sensitivity to antiepileptic drugs, a putative involvement of this channel in the cardiac mechanism of sudden unexpected death in epilepsy is also discussed.
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    ABSTRACT: Abstract Background/Aims: In vitro reprogramming of somatic cells holds great potential to serve as an autologous source of cells for tissue repair. However, major difficulties in achieving this potential include obtaining homogeneous and stable cells for transplantation. High electrical activity of cells such as cardiomyocytes (CMs) is crucial for both, safety and efficiency of cell replacement therapy. Moreover, the function of the cardiac pacemaker is controlled by the activities of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. Here we have examined changes in HCN gene expression and function during cardiomyogenesis. Methods: We differentiated murine iPS cells selected by an undifferentiated transcription factor 1 (UTF 1) -promoter-driven G418 resistance to CMs in vitro and characterized them by RT-PCR, immunocytochemistry, and electrophysiology. Results: As key cardiac markers alpha-actinin and cardiac troponin T could be identified in derived CMs. Immunocytochemical staining of CMs showed the presence of all HCN subunits (HCN1-4). Electrophysiology experiments revealed developmental changes of action potentials and I f currents as well as functional hormonal regulation and sensitivity to I f channel blockers. Conclusion: We conclude that iPS cells derived from UTF-selection give rise to functional CMs in vitro, with established hormonal regulation pathways and functionally expressed I f current in a development-dependent manner; and have all phenotypes with the pacemaker as predominant subtype. This might be of great importance for transplantation purposes.
    Cellular Physiology and Biochemistry 09/2014; 34(4):1199-1215. DOI:10.1159/000366332 · 3.55 Impact Factor
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    ABSTRACT: Objective Skeletal myoblasts fuse to form functional syncytical myotubes as an integral part of the skeletal muscle. During this differentiation process expression of proteins for mechanical and electrical integration is seized, which represents a major hindrance towards the application of skeletal myoblasts in cardiac regenerative cell therapy, as global heart function is dependent on intercellular communication. Methods We epicardially transplanted mechanically preconditioned engineered tissue constructs, containing neonatal mouse skeletal myoblasts. Y-chromosomal specific PCR was undertaken up to 10 weeks after transplantation to confirm the presence of grafted cells. Histological and electrophysiological analyses were carried out one week after transplantation. Results Cells within the grafted construct expressed connexin 43 at the interface to the host myocardium, indicating electrical coupling, confirmed by sharp electrode recordings. Analyses on maximum stimulation frequency (5.65 ± 0.37 Hz), conduction velocity (0.087 ± 0.011 m/s) and sensitivity for pharmacological conduction block (0.736 ± 0.080 mM 1-heptanol) revealed effective electrophysiological coupling between graft and host cells, although significantly less robust than in native myocardial tissue (maximum stimulation frequency: 11.616 ± 0.238 Hz, p < 0.001; conduction velocity: 0.300 ± 0.057 m/s; p < 0.01; conduction block: 1.983 ± 0.077 mM 1-heptanol; p < 0.001). Conclusions While untreated skeletal myoblasts cannot couple to cardiomyocytes, we confirm that mechanical preconditioning enables transplanted skeletal myoblasts to functionally interact with cardiomyocytes in vivo and, thus, reinvigorate the concept of skeletal myoblast based cardiac cell therapy.
    Journal of Thoracic and Cardiovascular Surgery 09/2014; 149(1). DOI:10.1016/j.jtcvs.2014.09.034 · 3.99 Impact Factor
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    ABSTRACT: Cell loss after transplantation is a major limitation for cell replacement approaches in regenerative medicine. To assess the survival kinetics of induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CM) we generated transgenic murine iPSC lines which, in addition to CM-specific expression of puromycin N-acetyl-transferase and enhanced green fluorescent protein (EGFP), also constitutively express firefly luciferase (FLuc) for bioluminescence (BL) in vivo imaging. While undifferentiated iPSC lines generated by random integration of the transgene into the genome retained stable FLuc activity over many passages, the BL signal intensity was strongly decreased in purified iPS-CM compared to undifferentiated iPSC. Targeted integration of FLuc-expression cassette into the ROSA26 genomic locus using zinc finger nuclease (ZFN) technology strongly reduced transgene silencing in iPS-CM, leading to a several-fold higher BL compared to iPS-CM expressing FLuc from random genomic loci. To investigate the survival kinetics of iPS-CM in vivo, purified CM obtained from iPSC lines expressing FLuc from a random or the ROSA26 locus were transplanted into cryoinfarcted hearts of syngeneic mice. Engraftment of viable cells was monitored by BL imaging over 4 weeks. Transplanted iPS-CM were poorly retained in the myocardium independently of the cell line used. However, up to 8% of cells survived for 28 days at the site of injection, which was confirmed by immunohistological detection of EGFP-positive iPS-CM in the host tissue. Transplantation of iPS-CM did not affect the scar formation or capillary density in the periinfarct region of host myocardium. This report is the first to determine the survival kinetics of drug-selected iPS-CM in the infarcted heart using BL imaging and demonstrates that transgene silencing in the course of iPSC differentiation can be greatly reduced by employing genome editing technology. FLuc-expressing iPS-CM generated in this study will enable further studies to reduce their loss, increase long-term survival and functional integration upon transplantation.
    PLoS ONE 09/2014; 9(9):e107363. DOI:10.1371/journal.pone.0107363 · 3.53 Impact Factor

Publication Stats

19k Citations
2,223.99 Total Impact Points

Institutions

  • 1995–2015
    • University of Cologne
      • • Institute of Neurophysiology
      • • Center for Physiology and Pathophysiology
      • • Department of Neurobiology and Animal Physiology
      Köln, North Rhine-Westphalia, Germany
    • Institut für klinische Pharmakologie
      Stuttgart, Baden-Württemberg, Germany
  • 2014
    • Technische Universität Dortmund
      • Leibniz Research Centre for Working Environment and Human Factors
      Dortmund, North Rhine-Westphalia, Germany
  • 2013
    • Cairo University
      Al Qāhirah, Al Qāhirah, Egypt
  • 2012
    • Heinrich-Heine-Universität Düsseldorf
      Düsseldorf, North Rhine-Westphalia, Germany
  • 2010
    • Universität Konstanz
      Constance, Baden-Württemberg, Germany
    • Max-Delbrück-Centrum für Molekulare Medizin
      Berlín, Berlin, Germany
  • 2007–2008
    • University of Bonn
      • Institut für Physiologie I
      Bonn, North Rhine-Westphalia, Germany
    • Columbia University
      New York, New York, United States
  • 2005
    • Robert Koch Institut
      Berlín, Berlin, Germany
  • 2003–2005
    • Huazhong University of Science and Technology
      Wu-han-shih, Hubei, China
  • 1999
    • University of Hamburg
      • Department of Neuroanatomy
      Hamburg, Hamburg, Germany
  • 1997
    • Max Planck Institute of Biochemistry
      München, Bavaria, Germany
  • 1988–1996
    • Freie Universität Berlin
      • Institute of Pharmacology and Toxicology
      Berlin, Land Berlin, Germany
  • 1991–1994
    • Humboldt-Universität zu Berlin
      • Department of Biology
      Berlin, Land Berlin, Germany
  • 1992
    • Leibniz Institute of Plant Genetics and Crop Plant Research
      Gatersleben, Saxony-Anhalt, Germany
    • Dallas Zoo
      Dallas, Texas, United States
  • 1982–1990
    • Universität des Saarlandes
      Saarbrücken, Saarland, Germany