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Functional expression of the Ca 2+ signaling machinery in human embryonic stem cells. Acta Pharmacol Sin 2017; 38:1663-1672. [PMID: 28713161 DOI: 10.1038/aps.2017.29] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 03/13/2017] [Indexed: 12/28/2022] Open
Abstract
Emerging evidence suggests that Ca2+ signals are important for the self-renewal and differentiation of human embryonic stem cells (hESCs). However, little is known about the physiological and pharmacological properties of the Ca2+-handling machinery in hESCs. In this study we used RT-PCR and Western blotting to analyze the expression profiles of genes encoding Ca2+-handling proteins; we also used confocal Ca2+ imaging and pharmacological approaches to determine the contribution of the Ca2+-handling machinery to the regulation of Ca2+ signaling in hESCs. We revealed that hESCs expressed pluripotent markers and various Ca2+-handling-related genes. ATP-induced Ca2+ transients in almost all hESCs were inhibited by the inositol-1,4,5-triphosphate receptor (IP3R) blocker 2-APB or xestospongin C. In addition, Ca2+ transients were induced by a ryanodine receptor (RyR) activator, caffeine, in 10%-15% of hESCs and were blocked by ryanodine, whereas caffeine and ATP did not have additive effects. Moreover, store-operated Ca2+ entry (SOCE) but not voltage-operated Ca2+ channel-mediated Ca2+ entry was observed. Inhibition of sarco/endoplasmic reticulum (ER) Ca2+-ATPase (SERCA) by thapsigargin induced a significant increase in the cytosolic free Ca2+ concentration ([Ca2+]i). For the Ca2+ extrusion pathway, inhibition of plasma membrane Ca2+ pumps (PMCAs) by carboxyeosin induced a slow increase in [Ca2+]i, whereas the Na+/Ca2+ exchanger (NCX) inhibitor KBR7943 induced a rapid increase in [Ca2+]i. Taken together, increased [Ca2+]i is mainly mediated by Ca2+ release from intracellular stores via IP3Rs. In addition, RyRs function in a portion of hESCs, thus indicating heterogeneity of the Ca2+-signaling machinery in hESCs; maintenance of low [Ca2+]i is mediated by uptake of cytosolic Ca2+ into the ER via SERCA and extrusion of Ca2+ out of cells via NCX and PMCA in hESCs.
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Calcium signaling in human pluripotent stem cells. Cell Calcium 2016; 59:117-23. [PMID: 26922096 DOI: 10.1016/j.ceca.2016.01.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 01/14/2016] [Accepted: 01/19/2016] [Indexed: 01/24/2023]
Abstract
Human pluripotent stem cells provide new tools for developmental and pharmacological studies as well as for regenerative medicine applications. Calcium homeostasis and ligand-dependent calcium signaling are key components of major cellular responses, including cell proliferation, differentiation or apoptosis. Interestingly, these phenomena have not been characterized in detail as yet in pluripotent human cell sates. Here we review the methods applicable for studying both short- and long-term calcium responses, focusing on the expression of fluorescent calcium indicator proteins and imaging methods as applied in pluripotent human stem cells. We discuss the potential regulatory pathways involving calcium responses in hPS cells and compare these to the implicated pathways in mouse PS cells. A recent development in the stem cell field is the recognition of so called "naïve" states, resembling the earliest potential forms of stem cells during development, as well as the "fuzzy" stem cells, which may be alternative forms of pluripotent cell types, therefore we also discuss the potential role of calcium homeostasis in these PS cell types.
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Kim YE, Park JA, Park SK, Kang HB, Kwon HJ, Lee Y. Enhancement of Transgene Expression by HDAC Inhibitors in Mouse Embryonic Stem Cells. Dev Reprod 2015; 17:379-87. [PMID: 25949154 PMCID: PMC4382945 DOI: 10.12717/dr.2013.17.4.379] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Revised: 12/07/2013] [Accepted: 12/13/2013] [Indexed: 12/04/2022]
Abstract
Embryonic stem (ES) cells can self-renew and differentiate to various cells depending on the culture condition. Although ES cells are a good model for cell type specification and can be useful for application in clinics in the future, studies on ES cells have many experimental restraints including low transfection efficiency and transgene expression. Here, we observed that transgene expression after transfection was enhanced by treatment with histone deacetylse (HDAC) inhibitors such as trichostatin A, sodium butyrate, and valproic acid. Transfection was performed using conventional transfection reagents with a retroviral vector encoding GFP under the control of CMV promoter as a reporter. Treatment of ES cells with HDAC inhibitors after transfection increased population of GFP positive cells up to 180% compared with untreated control. ES cells showed normal expression of stem cell markers after treatment with HDAC inhibitors. Transgene expression was further enhanced by modifying transfection procedure. GFP positive cells selected after transfection were proved to have the stem cell properties. Our improved protocol for enhanced gene delivery and expression in mouse ES cells without hampering ES cell properties will be useful for study and application of ES cells.
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Affiliation(s)
- Young-Eun Kim
- Department of Biochemistry, College of Natural Sciences, Republic of Korea ; Biotechnology Research Institute, Chungbuk National University, Cheongju 361-763, Republic of Korea
| | - Jeong-A Park
- Department of Biochemistry, College of Natural Sciences, Republic of Korea
| | - Sang-Kyu Park
- Department of Biochemistry, College of Natural Sciences, Republic of Korea
| | - Ho-Bum Kang
- Biotechnology Research Institute, Chungbuk National University, Cheongju 361-763, Republic of Korea
| | - Hyung-Joo Kwon
- Center for Medical Science Research, Republic of Korea ; Department of Microbiology, College of Medicine, Hallym University, Chuncheon 200-702, Republic of Korea
| | - Younghee Lee
- Department of Biochemistry, College of Natural Sciences, Republic of Korea ; Biotechnology Research Institute, Chungbuk National University, Cheongju 361-763, Republic of Korea
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STAT1β is not dominant negative and is capable of contributing to gamma interferon-dependent innate immunity. Mol Cell Biol 2014; 34:2235-48. [PMID: 24710278 DOI: 10.1128/mcb.00295-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The transcription factor STAT1 is essential for interferon (IFN)-mediated immunity in humans and mice. STAT1 function is tightly regulated, and both loss- and gain-of-function mutations result in severe immune diseases. The two alternatively spliced isoforms, STAT1α and STAT1β, differ with regard to a C-terminal transactivation domain, which is absent in STAT1β. STAT1β is considered to be transcriptionally inactive and to be a competitive inhibitor of STAT1α. To investigate the functions of the STAT1 isoforms in vivo, we generated mice deficient for either STAT1α or STAT1β. As expected, the functions of STAT1α and STAT1β in IFN-α/β- and IFN-λ-dependent antiviral activity are largely redundant. In contrast to the current dogma, however, we found that STAT1β is transcriptionally active in response to IFN-γ. In the absence of STAT1α, STAT1β shows more prolonged IFN-γ-induced phosphorylation and promoter binding. Both isoforms mediate protective, IFN-γ-dependent immunity against the bacterium Listeria monocytogenes, although with remarkably different efficiencies. Our data shed new light on the potential contributions of the individual STAT1 isoforms to STAT1-dependent immune responses. Knowledge of STAT1β's function will help fine-tune diagnostic approaches and help design more specific strategies to interfere with STAT1 activity.
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Prchal-Murphy M, Semper C, Lassnig C, Wallner B, Gausterer C, Teppner-Klymiuk I, Kobolak J, Müller S, Kolbe T, Karaghiosoff M, Dinnyés A, Rülicke T, Leitner NR, Strobl B, Müller M. TYK2 kinase activity is required for functional type I interferon responses in vivo. PLoS One 2012; 7:e39141. [PMID: 22723949 PMCID: PMC3377589 DOI: 10.1371/journal.pone.0039141] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 05/20/2012] [Indexed: 01/25/2023] Open
Abstract
Tyrosine kinase 2 (TYK2) is a member of the Janus kinase (JAK) family and is involved in cytokine signalling. In vitro analyses suggest that TYK2 also has kinase-independent, i.e., non-canonical, functions. We have generated gene-targeted mice harbouring a mutation in the ATP-binding pocket of the kinase domain. The Tyk2 kinase-inactive (Tyk2K923E) mice are viable and show no gross abnormalities. We show that kinase-active TYK2 is required for full-fledged type I interferon- (IFN) induced activation of the transcription factors STAT1-4 and for the in vivo antiviral defence against viruses primarily controlled through type I IFN actions. In addition, TYK2 kinase activity was found to be required for the protein’s stability. An inhibitory function was only observed upon over-expression of TYK2K923Ein vitro. Tyk2K923E mice represent the first model for studying the kinase-independent function of a JAK in vivo and for assessing the consequences of side effects of JAK inhibitors.
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Affiliation(s)
- Michaela Prchal-Murphy
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
| | - Christian Semper
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
| | - Caroline Lassnig
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
- Biomodels Austria, University of Veterinary Medicine, Vienna, Austria
| | - Barbara Wallner
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
| | - Christian Gausterer
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
| | | | - Julianna Kobolak
- Genetic Reprogramming Group Agricultural Biotechnology Center, Gödöllö, Hungary
| | - Simone Müller
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
| | - Thomas Kolbe
- Biomodels Austria, University of Veterinary Medicine, Vienna, Austria
- Department for Agrobiotechnology IFA Tulln, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Marina Karaghiosoff
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
| | - Andras Dinnyés
- Genetic Reprogramming Group Agricultural Biotechnology Center, Gödöllö, Hungary
- Molecular Animal Biotechnology Laboratory, Szent Istvan University, Gödöllö, Hungary
- BioTalentum Ltd., Gödöllö, Hungary
| | - Thomas Rülicke
- Biomodels Austria, University of Veterinary Medicine, Vienna, Austria
- Institute of Laboratory Animal Science, University of Veterinary Medicine, Vienna, Austria
| | - Nicole R. Leitner
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
| | - Birgit Strobl
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
| | - Mathias Müller
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
- Biomodels Austria, University of Veterinary Medicine, Vienna, Austria
- * E-mail:
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Apáti Á, Pászty K, Erdei Z, Szebényi K, Homolya L, Sarkadi B. Calcium signaling in pluripotent stem cells. Mol Cell Endocrinol 2012; 353:57-67. [PMID: 21945604 DOI: 10.1016/j.mce.2011.08.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 08/30/2011] [Accepted: 08/30/2011] [Indexed: 10/17/2022]
Abstract
Pluripotent stem cells represent a new source of biological material allowing the exploration of signaling phenomena during normal cell development and differentiation. Still, the calcium signaling pathways and intracellular calcium responses to various ligands or stress conditions have not been sufficiently explored as yet in embryonic or induced pluripotent stem cells and in their differentiated offspring. This is partly due to the special culturing conditions of these cell types, the rapid morphological and functional changes in heterogeneous cell populations during early differentiation, and methodological problems in cellular calcium measurements. In this paper, we review the currently available data in the literature on calcium signaling in pluripotent stem cells and discuss the potential shortcomings of these studies. Various assay methods are surveyed for obtaining reliable data both in undifferentiated embryonic stem cells and in specific, stem cell-derived human tissues. In this paper, we present the modulation of calcium signaling in human embryonic stem cells (hESC) and in their derivates; mesenchymal stem cell like (MSCl) cells and cardiac tissues using the fluorescent calcium indicator Fluo-4 and confocal microscopy. LPA, trypsin and angiotensin II were effective in inducing calcium signals both in HUES9 and MSCl cells. Histamine and thrombin induced calcium signal exclusively in the MSCl cells, while ATP was effective only in HUES9 cells. There was no calcium signal evoked by GABA, even at relatively high concentrations. In stem cell-derived cardiomyocytes a rapid increase in the beating rate and an increase of the calcium signal peaks could be observed after the addition of adrenaline, while verapamil led to a strong decrease in cellular calcium and stopped spontaneous contractions in a relaxed state.
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Affiliation(s)
- Ágota Apáti
- Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
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