1
|
Radiation Response of Murine Embryonic Stem Cells. Cells 2020; 9:cells9071650. [PMID: 32660081 PMCID: PMC7408589 DOI: 10.3390/cells9071650] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/18/2020] [Accepted: 07/01/2020] [Indexed: 12/13/2022] Open
Abstract
To understand the mechanisms of disturbed differentiation and development by radiation, murine CGR8 embryonic stem cells (mESCs) were exposed to ionizing radiation and differentiated by forming embryoid bodies (EBs). The colony forming ability test was applied for survival and the MTT test for viability determination after X-irradiation. Cell cycle progression was determined by flow cytometry of propidium iodide-stained cells, and DNA double strand break (DSB) induction and repair by γH2AX immunofluorescence. The radiosensitivity of mESCs was slightly higher compared to the murine osteoblast cell line OCT-1. The viability 72 h after X-irradiation decreased dose-dependently and was higher in the presence of leukemia inhibitory factor (LIF). Cells exposed to 2 or 7 Gy underwent a transient G2 arrest. X-irradiation induced γH2AX foci and they disappeared within 72 h. After 72 h of X-ray exposure, RNA was isolated and analyzed using genome-wide microarrays. The gene expression analysis revealed amongst others a regulation of developmental genes (Ada, Baz1a, Calcoco2, Htra1, Nefh, S100a6 and Rassf6), downregulation of genes involved in glycolysis and pyruvate metabolism whereas upregulation of genes related to the p53 signaling pathway. X-irradiated mESCs formed EBs and differentiated toward cardiomyocytes but their beating frequencies were lower compared to EBs from unirradiated cells. These results suggest that X-irradiation of mESCs deregulate genes related to the developmental process. The most significant biological processes found to be altered by X-irradiation in mESCs were the development of cardiovascular, nervous, circulatory and renal system. These results may explain the X-irradiation induced-embryonic lethality and malformations observed in animal studies.
Collapse
|
2
|
Mayer M, Arrizabalaga O, Ciba M, Schroeder IS, Ritter S, Thielemann C. Novel in vitro assay to investigate radiation induced changes in the functionality of human embryonic stem cell-derived neurospheres. Neurotoxicology 2020; 79:40-47. [PMID: 32320710 DOI: 10.1016/j.neuro.2020.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 03/31/2020] [Accepted: 04/15/2020] [Indexed: 10/24/2022]
Abstract
Ionizing radiation (IR) is increasingly used for diagnostics and therapy of severe brain diseases. However, IR also has adverse effects on the healthy brain tissue, particularly on the neuronal network. This is true for adults but even more pronounced in the developing brain of unborn and pediatric patients. Epidemiological studies on children receiving radiotherapy showed an increased risk for cognitive decline ranging from mild deficits in academic functioning to severe late effects in intellectual ability and language as a consequence of altered neuronal development and connectivity. To provide a comprehensive approach for the analysis of radiation-induced alterations in human neuronal functionality, we developed an in vitro assay by combining microelectrode array (MEA) analyses and human embryonic stem cell (hESC) derived three-dimensional neurospheres (NS). In our proof of principle study, we irradiated hESC with 1 Gy X-rays and let them spontaneously differentiate into neurons within NS. After the onset of neuronal activity, we recorded and analyzed the activity pattern of the developing neuronal networks. The network activity in NS derived from irradiated hESC was significantly reduced, whereas no differences in molecular endpoints such as cell proliferation and transcript or protein expression analyses were found. Thus, the combination of MEA analysis with a 3D model for neuronal functionality revealed radiation sequela that otherwise would not have been detected. We therefore strongly suggest combining traditional biomolecular methods with the new functional assay presented in this work to improve the risk assessment for IR-induced effects on the developing brain.
Collapse
Affiliation(s)
- Margot Mayer
- TH Aschaffenburg University of Applied Sciences, BioMEMS Lab, Aschaffenburg, Germany.
| | - Onetsine Arrizabalaga
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Division, Darmstadt, Germany.
| | - Manuel Ciba
- TH Aschaffenburg University of Applied Sciences, BioMEMS Lab, Aschaffenburg, Germany.
| | - Insa S Schroeder
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Division, Darmstadt, Germany.
| | - Sylvia Ritter
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Division, Darmstadt, Germany.
| | - Christiane Thielemann
- TH Aschaffenburg University of Applied Sciences, BioMEMS Lab, Aschaffenburg, Germany.
| |
Collapse
|
3
|
Gupta D, Heinen CD. The mismatch repair-dependent DNA damage response: Mechanisms and implications. DNA Repair (Amst) 2019; 78:60-69. [PMID: 30959407 DOI: 10.1016/j.dnarep.2019.03.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/25/2019] [Accepted: 03/16/2019] [Indexed: 12/22/2022]
Abstract
An important role for the DNA mismatch repair (MMR) pathway in maintaining genomic stability is embodied in its conservation through evolution and the link between loss of MMR function and tumorigenesis. The latter is evident as inheritance of mutations within the major MMR genes give rise to the cancer predisposition condition, Lynch syndrome. Nonetheless, how MMR loss contributes to tumorigenesis is not completely understood. In addition to preventing the accumulation of mutations, MMR also directs cellular responses, such as cell cycle checkpoint or apoptosis activation, to different forms of DNA damage. Understanding this MMR-dependent DNA damage response may provide insight into the full tumor suppressing capabilities of the MMR pathway. Here, we delve into the proposed mechanisms for the MMR-dependent response to DNA damaging agents. We discuss how these pre-clinical findings extend to the clinical treatment of cancers, emphasizing MMR status as a crucial variable in selection of chemotherapeutic regimens. Also, we discuss how loss of the MMR-dependent damage response could promote tumorigenesis via the establishment of a survival advantage to endogenous levels of stress in MMR-deficient cells.
Collapse
Affiliation(s)
- Dipika Gupta
- Center for Molecular Oncology, UConn Health, Farmington, CT 06030, USA
| | | |
Collapse
|
4
|
Fabbrizi MR, Warshowsky KE, Zobel CL, Hallahan DE, Sharma GG. Molecular and epigenetic regulatory mechanisms of normal stem cell radiosensitivity. Cell Death Discov 2018; 4:117. [PMID: 30588339 PMCID: PMC6299079 DOI: 10.1038/s41420-018-0132-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/01/2018] [Accepted: 11/20/2018] [Indexed: 12/14/2022] Open
Abstract
Ionizing radiation (IR) therapy is a major cancer treatment modality and an indispensable auxiliary treatment for primary and metastatic cancers, but invariably results in debilitating organ dysfunctions. IR-induced depletion of neural stem/progenitor cells in the subgranular zone of the dentate gyrus in the hippocampus where neurogenesis occurs is considered largely responsible for deficiencies such as learning, memory, and spatial information processing in patients subjected to cranial irradiation. Similarly, IR therapy-induced intestinal injuries such as diarrhea and malabsorption are common side effects in patients with gastrointestinal tumors and are believed to be caused by intestinal stem cell drop out. Hematopoietic stem cell transplantation is currently used to reinstate blood production in leukemia patients and pre-clinical treatments show promising results in other organs such as the skin and kidney, but ethical issues and logistic problems make this route difficult to follow. An alternative way to restore the injured tissue is to preserve the stem cell pool located in that specific tissue/organ niche, but stem cell response to ionizing radiation is inadequately understood at the molecular mechanistic level. Although embryonic and fetal hypersensity to IR has been very well known for many decades, research on embryonic stem cell models in culture concerning molecular mechanisms have been largely inconclusive and often in contradiction of the in vivo observations. This review will summarize the latest discoveries on stem cell radiosensitivity, highlighting the possible molecular and epigenetic mechanism(s) involved in DNA damage response and programmed cell death after ionizing radiation therapy specific to normal stem cells. Finally, we will analyze the possible contribution of stem cell-specific chromatin's epigenetic constitution in promoting normal stem cell radiosensitivity.
Collapse
Affiliation(s)
- Maria Rita Fabbrizi
- Cancer Biology Division, Department of Radiation Oncology, Washington University School of Medicine, 4511 Forest Park, Saint Louis, MO 63108 USA
| | - Kacie E. Warshowsky
- Cancer Biology Division, Department of Radiation Oncology, Washington University School of Medicine, 4511 Forest Park, Saint Louis, MO 63108 USA
| | - Cheri L. Zobel
- Cancer Biology Division, Department of Radiation Oncology, Washington University School of Medicine, 4511 Forest Park, Saint Louis, MO 63108 USA
| | - Dennis E. Hallahan
- Cancer Biology Division, Department of Radiation Oncology, Washington University School of Medicine, 4511 Forest Park, Saint Louis, MO 63108 USA
- Siteman Cancer Center, Washington University School of Medicine, Saint Louis, MO 63108 USA
| | - Girdhar G. Sharma
- Cancer Biology Division, Department of Radiation Oncology, Washington University School of Medicine, 4511 Forest Park, Saint Louis, MO 63108 USA
- Siteman Cancer Center, Washington University School of Medicine, Saint Louis, MO 63108 USA
| |
Collapse
|
5
|
Ngan Tran K, Choi JI. Gene expression profiling of rat livers after continuous whole-body exposure to low-dose rate of gamma rays. Int J Radiat Biol 2018; 94:434-442. [PMID: 29557699 DOI: 10.1080/09553002.2018.1455009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To study gene expression modulation in response to continuous whole-body exposure to low-dose-rate gamma radiation and improve our understanding of the mechanism of this impact at the molecular basis. MATERIALS AND METHODS cDNA microarray method with complete pooling of samples was used to study expression changes in the transcriptome profile of livers from rats treated with prolonged low-dose-rate ionizing radiation (IR) relative to that of sham-irradiated rats. RESULTS Of the 209 genes that were two-fold-up or down-regulated, 143 were known genes of which 27 were found in previous literatures to be modulated by IR. Remarkably, there were a significant number of differentially expressed genes involved in hepatic lipid metabolism. CONCLUSION This study showed changes in transcriptome profile of livers from low-dose irradiated rats when compared with that of sham-irradiated ones. This study will be useful for studying the metabolic changes of human exposed for long term to cosmic ray such as in space and in polar regions.
Collapse
Affiliation(s)
- Kim Ngan Tran
- a Department of Biotechnology and Bioengineering, Interdisciplinary Program for Bioenergy & Biomaterials , Chonnam National University , Gwangju , South Korea
| | - Jong-Il Choi
- a Department of Biotechnology and Bioengineering, Interdisciplinary Program for Bioenergy & Biomaterials , Chonnam National University , Gwangju , South Korea
| |
Collapse
|
6
|
Krizkova S, Kepinska M, Emri G, Eckschlager T, Stiborova M, Pokorna P, Heger Z, Adam V. An insight into the complex roles of metallothioneins in malignant diseases with emphasis on (sub)isoforms/isoforms and epigenetics phenomena. Pharmacol Ther 2017; 183:90-117. [PMID: 28987322 DOI: 10.1016/j.pharmthera.2017.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Metallothioneins (MTs) belong to a group of small cysteine-rich proteins that are ubiquitous throughout all kingdoms. The main function of MTs is scavenging of free radicals and detoxification and homeostating of heavy metals. In humans, 16 genes localized on chromosome 16 have been identified to encode four MT isoforms labelled by numbers (MT-1-MT-4). MT-2, MT-3 and MT-4 proteins are encoded by a single gene. MT-1 comprises many (sub)isoforms. The known active MT-1 genes are MT-1A, -1B, -1E, -1F, -1G, -1H, -1M and -1X. The rest of the MT-1 genes (MT-1C, -1D, -1I, -1J and -1L) are pseudogenes. The expression and localization of individual MT (sub)isoforms and pseudogenes vary at intra-cellular level and in individual tissues. Changes in MT expression are associated with the process of carcinogenesis of various types of human malignancies, or with a more aggressive phenotype and therapeutic resistance. Hence, MT (sub)isoform profiling status could be utilized for diagnostics and therapy of tumour diseases. This review aims on a comprehensive summary of methods for analysis of MTs at (sub)isoforms levels, their expression in single tumour diseases and strategies how this knowledge can be utilized in anticancer therapy.
Collapse
Affiliation(s)
- Sona Krizkova
- Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno, Czech Republic; Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic
| | - Marta Kepinska
- Department of Biomedical and Environmental Analysis, Faculty of Pharmacy, Wroclaw Medical University, Borowska 211, 50-556 Wroclaw, Poland
| | - Gabriella Emri
- Department of Dermatology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, H-4032 Debrecen, Hungary
| | - Tomas Eckschlager
- Department of Paediatric Haematology and Oncology, 2nd Faculty of Medicine, Charles University, and University Hospital Motol, V Uvalu 84, CZ-150 06 Prague 5, Czech Republic
| | - Marie Stiborova
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, CZ-128 40 Prague 2, Czech Republic
| | - Petra Pokorna
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, CZ-128 40 Prague 2, Czech Republic; Department of Oncology, 2nd Faculty of Medicine, Charles University, and University Hospital Motol, V Uvalu 84, CZ-150 06 Prague 5, Czech Republic
| | - Zbynek Heger
- Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno, Czech Republic; Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic
| | - Vojtech Adam
- Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno, Czech Republic; Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic.
| |
Collapse
|
7
|
Luft S, Arrizabalaga O, Kulish I, Nasonova E, Durante M, Ritter S, Schroeder IS. Ionizing Radiation Alters Human Embryonic Stem Cell Properties and Differentiation Capacity by Diminishing the Expression of Activin Receptors. Stem Cells Dev 2016; 26:341-352. [PMID: 27937745 DOI: 10.1089/scd.2016.0277] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Exposure of the embryo to ionizing radiation (IR) is detrimental as it can cause genotoxic stress leading to immediate and latent consequences such as functional defects, malformations, or cancer. Human embryonic stem (hES) cells can mimic the preimplantation embryo and help to assess the biological effects of IR during early development. In this study, we describe the alterations H9 hES cells exhibit after X-ray irradiation in respect to cell cycle progression, apoptosis, genomic stability, stem cell signaling, and their capacity to differentiate into definitive endoderm. Early postirradiation, hES cells responded with an arrest in G2/M phase, elevated apoptosis, and increased chromosomal aberrations. Significant downregulation of stem cell signaling markers of the TGF beta-, Wnt-, and Hedgehog pathways was observed. Most prominent were alterations in the expression of activin receptors. However, hES cells responded differently depending on the culture conditions chosen for maintenance. Enzymatically passaged cells were less sensitive to IR than mechanically passaged ones showing fewer apoptotic cells and fewer changes in the stem cell signaling 24 h after irradiation, but displayed higher levels of chromosomal aberrations. Even though many of the observed changes were transient, surviving hES cells, which were differentiated 4 days postirradiation, showed a lower efficiency to form definitive endoderm than their mock-irradiated counterparts. This was demonstrated by lower expression levels of SOX17 and microRNA miR-375. In conclusion, hES cells are a suitable tool for the IR risk assessment during early human development. However, careful choice of the culture methods and a vigorous monitoring of the stem cell quality are mandatory for the use of these cells. Exposure to IR influences the stem cell properties of hES cells even when immediate radiation effects are overcome. This warrants consideration in the risk assessment of radiation effects during the earliest stages of human development.
Collapse
Affiliation(s)
- Sabine Luft
- 1 Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research , Darmstadt, Germany
| | - Onetsine Arrizabalaga
- 1 Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research , Darmstadt, Germany
| | - Ireen Kulish
- 1 Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research , Darmstadt, Germany .,2 Technical University Darmstadt , Darmstadt, Germany
| | - Elena Nasonova
- 1 Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research , Darmstadt, Germany .,3 Laboratory of Radiation Biology, Joint Institute for Nuclear Research , Dubna, Russia
| | - Marco Durante
- 1 Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research , Darmstadt, Germany
| | - Sylvia Ritter
- 1 Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research , Darmstadt, Germany
| | - Insa S Schroeder
- 1 Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research , Darmstadt, Germany
| |
Collapse
|
8
|
Krizkova S, Kepinska M, Emri G, Rodrigo MAM, Tmejova K, Nerudova D, Kizek R, Adam V. Microarray analysis of metallothioneins in human diseases—A review. J Pharm Biomed Anal 2016; 117:464-73. [DOI: 10.1016/j.jpba.2015.09.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 09/23/2015] [Accepted: 09/25/2015] [Indexed: 01/11/2023]
|
9
|
A Genomic Study of DNA Alteration Events Caused by Ionizing Radiation in Human Embryonic Stem Cells via Next-Generation Sequencing. Stem Cells Int 2015; 2016:1346521. [PMID: 26709353 PMCID: PMC4670683 DOI: 10.1155/2016/1346521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/29/2015] [Accepted: 06/02/2015] [Indexed: 01/03/2023] Open
Abstract
Ionizing radiation (IR) is a known mutagen that is widely employed for medical diagnostic and therapeutic purposes. To study the extent of genetic variations in DNA caused by IR, we used IR-sensitive human embryonic stem cells (hESCs). Four hESC cell lines, H1, H7, H9, and H14, were subjected to IR at 0.2 or 1 Gy dose and then maintained in culture for four days before being harvested for DNA isolation. Irradiation with 1 Gy dose resulted in significant cell death, ranging from 60% to 90% reduction in cell population. Since IR is often implicated as a risk for inducing cancer, a primer pool targeting genomic “hotspot” regions that are frequently mutated in human cancer genes was used to generate libraries from irradiated and control samples. Using a semiconductor-based next-generation sequencing approach, we were able to consistently sequence these samples with deep coverage for reliable data analysis. A possible rare nucleotide variant was identified in the KIT gene (chr4:55593481) exclusively in H1 hESCs irradiated with 1 Gy dose. More extensive further studies are warranted to assess the extent and distribution of genetic changes in hESCs after IR exposure.
Collapse
|
10
|
Kavanagh JN, Waring EJ, Prise KM. Radiation responses of stem cells: targeted and non-targeted effects. RADIATION PROTECTION DOSIMETRY 2015; 166:110-117. [PMID: 25877536 DOI: 10.1093/rpd/ncv161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Stem cells are fundamental to the development of any tissue or organism via their ability to self-renew, which is aided by their unlimited proliferative capacity and their ability to produce fully differentiated offspring, often from multiple lineages. Stems cells are long lived and have the potential to accumulate mutations, including in response to radiation exposure. It is thought that stem cells have the potential to be induced into a cancer stem cell phenotype and that these may play an important role in resistance to radiotherapy. For radiation-induced carcinogenesis, the role of targeted and non-targeted effects is unclear with tissue or origin being important. Studies of genomic instability and bystander responses have shown consistent effects in haematopoietic models. Several models of radiation have predicted that stem cells play an important role in tumour initiation and that bystander responses could play a role in proliferation and self-renewal.
Collapse
Affiliation(s)
- J N Kavanagh
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - E J Waring
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| | - K M Prise
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7AE, UK
| |
Collapse
|
11
|
Comparative Analysis of Whole-Genome Gene Expression Changes in Cultured Human Embryonic Stem Cells in Response to Low, Clinical Diagnostic Relevant, and High Doses of Ionizing Radiation Exposure. Int J Mol Sci 2015; 16:14737-48. [PMID: 26133243 PMCID: PMC4519869 DOI: 10.3390/ijms160714737] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 05/23/2015] [Accepted: 06/26/2015] [Indexed: 11/16/2022] Open
Abstract
The biological effects of low-dose ionizing radiation (LDIR) exposure in humans are not comprehensively understood, generating a high degree of controversy in published literature. The earliest stages of human development are known to be among the most sensitive to stress exposures, especially genotoxic stresses. However, the risks stemming from exposure to LDIR, particularly within the clinical diagnostic relevant dose range, have not been directly evaluated in human embryonic stem cells (hESCs). Here, we describe the dynamics of the whole genome transcriptional responses of different hESC lines to both LDIR and, as a reference, high-dose IR (HDIR). We found that even doses as low as 0.05 Gy could trigger statistically significant transient changes in a rather limited subset of genes in all hESCs lines examined. Gene expression signatures of hESCs exposed to IR appear to be highly dose-, time-, and cell line-dependent. We identified 50 genes constituting consensus gene expression signature as an early response to HDIR across all lines of hESC examined. We observed substantial differences in biological pathways affected by either LDIR or HDIR in hESCs, suggesting that the molecular mechanisms underpinning the responses of hESC may fundamentally differ depending on radiation doses.
Collapse
|
12
|
Bogomazova AN, Vassina EM, Goryachkovskaya TN, Popik VM, Sokolov AS, Kolchanov NA, Lagarkova MA, Kiselev SL, Peltek SE. No DNA damage response and negligible genome-wide transcriptional changes in human embryonic stem cells exposed to terahertz radiation. Sci Rep 2015; 5:7749. [PMID: 25582954 PMCID: PMC4291560 DOI: 10.1038/srep07749] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 12/08/2014] [Indexed: 02/07/2023] Open
Abstract
Terahertz (THz) radiation was proposed recently for use in various applications, including medical imaging and security scanners. However, there are concerns regarding the possible biological effects of non-ionising electromagnetic radiation in the THz range on cells. Human embryonic stem cells (hESCs) are extremely sensitive to environmental stimuli, and we therefore utilised this cell model to investigate the non-thermal effects of THz irradiation. We studied DNA damage and transcriptome responses in hESCs exposed to narrow-band THz radiation (2.3 THz) under strict temperature control. The transcription of approximately 1% of genes was subtly increased following THz irradiation. Functional annotation enrichment analysis of differentially expressed genes revealed 15 functional classes, which were mostly related to mitochondria. Terahertz irradiation did not induce the formation of γH2AX foci or structural chromosomal aberrations in hESCs. We did not observe any effect on the mitotic index or morphology of the hESCs following THz exposure.
Collapse
Affiliation(s)
- A. N. Bogomazova
- Vavilov Institute of General Genetics RAS, Moscow, Russia
- Skoltech Center for Stem Cell Research, Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region, Russia
| | - E. M. Vassina
- Vavilov Institute of General Genetics RAS, Moscow, Russia
- Skoltech Center for Stem Cell Research, Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region, Russia
| | | | - V. M. Popik
- Budker Institute of Nucleic Physics SB RAS, Novosibirsk, Russia
| | | | | | - M. A. Lagarkova
- Vavilov Institute of General Genetics RAS, Moscow, Russia
- Scientific Research Institute of Physical-Chemical Medicine, Moscow, Russia
- Skoltech Center for Stem Cell Research, Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region, Russia
| | - S. L. Kiselev
- Vavilov Institute of General Genetics RAS, Moscow, Russia
- Skoltech Center for Stem Cell Research, Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region, Russia
| | - S. E. Peltek
- Institute of Cytology and Genetics RAS, Novosibirsk, Russia
| |
Collapse
|
13
|
Sokolov MV, Neumann RD. Changes in human pluripotent stem cell gene expression after genotoxic stress exposures. World J Stem Cells 2014; 6:598-605. [PMID: 25426256 PMCID: PMC4178259 DOI: 10.4252/wjsc.v6.i5.598] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/12/2014] [Accepted: 09/17/2014] [Indexed: 02/06/2023] Open
Abstract
Human pluripotent stem cells (hPSCs) represent heterogeneous populations, including induced pluripotent stem cells (iPSCs), endogenous plastic somatic cells, and embryonic stem cells (ESCs). Human ESCs are derived from the inner cell mass of the blastocyst, and they are characterized by the abilities to self-renew indefinitely, and to give rise to all cell types of embryonic lineage (pluripotency) under the guidance of the appropriate chemical, mechanical and environmental cues. The combination of these critical features is unique to hESCs, and set them apart from other human cells. The expectations are high to utilize hESCs for treating injuries and degenerative diseases; for modeling of complex illnesses and development; for screening and testing of pharmacological products; and for examining toxicity, mutagenicity, teratogenicity, and potential carcinogenic effects of a variety of environmental factors, including ionizing radiation (IR). Exposures to genotoxic stresses, such as background IR, are unavoidable; moreover, IR is widely used in diagnostic and therapeutic procedures in medicine on a routine basis. One of the key outcomes of cell exposures to IR is the change in gene expression, which may underlie the ultimate hESCs fate after such a stress. However, gaps in our knowledge about basic biology of hESCs impose a serious limitation to fully realize the potential of hESCs in practice. The purpose of this review is to examine the available evidence of alterations in gene expression in human pluripotent stem cells after genotoxic stress, and to discuss strategies for future research in this important area.
Collapse
|
14
|
Zhou D, Lin G, Zeng SC, Xiong B, Xie PY, Cheng DH, Zheng Q, Ouyang Q, Zhou XY, Tang WL, Sun Y, Lu GY, Lu GX. Trace levels of mitomycin C disrupt genomic integrity and lead to DNA damage response defect in long-term-cultured human embryonic stem cells. Arch Toxicol 2014; 89:33-45. [PMID: 24838295 DOI: 10.1007/s00204-014-1250-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 04/15/2014] [Indexed: 02/07/2023]
Abstract
How to maintain the genetic integrity of cultured human embryonic stem (hES) cells is raising crucial concerns for future clinical use in regenerative medicine. Mitomycin C(MMC), a DNA damage agent, is widely used for preparation of feeder cells in many laboratories. However, to what extent MMC affects the karyotypic stability of hES cells is not clear. Here, we measured residual MMC using High Performance Liquid Chromatography-Mass Spectrometry/Mass Spectrometry following each step of feeder preparation and found that 2.26 ± 0.77 and 3.50 ± 0.92 ng/ml remained in mouse feeder cells and human feeder cells, respectively. In addition, different amounts of MMC caused different chromosomal aberrations in hES cells. In particular, one abnormality, dup(1)(p32p36), was the same identical to one we previously reported in another hES cell line. Using Affymetrix SNP 6.0 arrays, the copy number variation changes of the hES cells maintained on MMC-inactivated feeders (MMC-feeder) were significantly more than those cultured on γ-inactivated feeder (IR-feeder) cells. Furthermore, DNA damage response (DDR) genes were down-regulated during long-term culture in the MMC-containing system, leading to DDR defect and shortened telomeres of hES cells, a sign of genomic instability. Therefore, MMC-feeder and MMC-induced genomic variation present an important safety problem that would limit such hES from being applied for future clinic use and drug screening.
Collapse
Affiliation(s)
- Di Zhou
- Institute of Reproduction and Stem Cell Engineering, Central South University, 8 Luyun Road, Changsha, 410000, Hunan, China
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Manda K, Kavanagh JN, Buttler D, Prise KM, Hildebrandt G. Low dose effects of ionizing radiation on normal tissue stem cells. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 761:6-14. [PMID: 24566131 DOI: 10.1016/j.mrrev.2014.02.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 02/03/2014] [Accepted: 02/13/2014] [Indexed: 12/18/2022]
Abstract
In recent years, there has been growing evidence for the involvement of stem cells in cancer initiation. As a result of their long life span, stem cells may have an increased propensity to accumulate genetic damage relative to differentiated cells. Therefore, stem cells of normal tissues may be important targets for radiation-induced carcinogenesis. Knowledge of the effects of ionizing radiation (IR) on normal stem cells and on the processes involved in carcinogenesis is very limited. The influence of high doses of IR (>5Gy) on proliferation, cell cycle and induction of senescence has been demonstrated in stem cells. There have been limited studies of the effects of moderate (0.5-5Gy) and low doses (<0.5Gy) of IR on stem cells however, the effect of low dose IR (LD-IR) on normal stem cells as possible targets for radiation-induced carcinogenesis has not been studied in any depth. There may also be important parallels between stem cell responses and those of cancer stem cells, which may highlight potential key common mechanisms of their response and radiosensitivity. This review will provide an overview of the current knowledge of radiation-induced effects on normal stem cells, with particular focus on low and moderate doses of IR.
Collapse
Affiliation(s)
- Katrin Manda
- Department of Radiotherapy and Radiation Oncology, University of Rostock, Suedring 75, 18059 Rostock, Germany.
| | - Joy N Kavanagh
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom.
| | - Dajana Buttler
- Department of Radiotherapy and Radiation Oncology, University of Rostock, Suedring 75, 18059 Rostock, Germany.
| | - Kevin M Prise
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom.
| | - Guido Hildebrandt
- Department of Radiotherapy and Radiation Oncology, University of Rostock, Suedring 75, 18059 Rostock, Germany.
| |
Collapse
|
16
|
Effects of low doses of ionizing radiation exposures on stress-responsive gene expression in human embryonic stem cells. Int J Mol Sci 2014; 15:588-604. [PMID: 24398983 PMCID: PMC3907827 DOI: 10.3390/ijms15010588] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 12/25/2013] [Accepted: 12/26/2013] [Indexed: 12/26/2022] Open
Abstract
There is a great deal of uncertainty on how low (≤0.1 Gy) doses of ionizing radiation (IR) affect human cells, partly due to a lack of suitable experimental model systems for such studies. The uncertainties arising from low-dose IR human data undermine practical societal needs to predict health risks emerging from diagnostic medical tests’ radiation, natural background radiation, and environmental radiological accidents. To eliminate a variability associated with remarkable differences in radioresponses of hundreds of differentiated cell types, we established a novel, human embryonic stem cell (hESC)-based model to examine the radiobiological effects in human cells. Our aim is to comprehensively elucidate the gene expression changes in a panel of various hESC lines following low IR doses of 0.01; 0.05; 0.1 Gy; and, as a reference, relatively high dose of 1 Gy of IR. Here, we examined the dynamics of transcriptional changes of well-established IR-responsive set of genes, including CDKN1A, GADD45A, etc. at 2 and 16 h post-IR, representing “early” and “late” radioresponses of hESCs. Our findings suggest the temporal- and hESC line-dependence of stress gene radioresponses with no statistically significant evidence for a linear dose-response relationship within the lowest doses of IR exposures.
Collapse
|
17
|
Chibly AM, Nguyen T, Limesand KH. Palliative Care for Salivary Gland Dysfunction Highlights the Need for Regenerative Therapies: A Review on Radiation and Salivary Gland Stem Cells. ACTA ACUST UNITED AC 2014; 4. [PMID: 26693098 DOI: 10.4172/2165-7386.1000180] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Radiotherapy remains the major course of treatment for Head and Neck cancer patients. A common consequence of radiation treatment is dysfunction of the salivary glands, which leads to a number of oral complications including xerostomia and dysphagia, for which there is no existent cure. Here, we briefly describe the current palliative treatments available for patients undergoing these conditions, such as oral lubricants, saliva substitutes, and saliva stimulants. None of these options achieves restoration of normal quality of life due to their limited effectiveness, and in some cases, adverse side effects of their own. Other therapies under development, such as acupuncture and electrostimulation have also yielded mixed results in clinical trials. Due to the ineffectiveness of palliative care to restore quality of life, it is reasonable to aim for the development of regenerative therapies that allow restoration of function of the salivary epithelium following radiation treatment. Adult stem cells are a necessary component of wound healing, and play important roles in preserving normal function of adult tissues. Thus, the present review mainly focuses on the effects of radiation on adult stem cells in a variety of tissues, which may be at play in the response of salivary glands to radiation treatment. This is of clinical importance because progenitor cells of the salivary glands have shown partial regenerative potential in mouse transplantation assays. Therefore, understanding how these progenitor cells are affected by radiation offers potential for development of new therapies for patients with xerostomia.
Collapse
Affiliation(s)
| | - Thao Nguyen
- The University of Arizona Nutritional Sciences Graduate Program, Tucson, AZ 85721, USA
| | - Kirsten H Limesand
- The University of Arizona Nutritional Sciences Graduate Program, Tucson, AZ 85721, USA
| |
Collapse
|
18
|
Lazo JS, Sharlow ER, Epperly MW, Lira A, Leimgruber S, Skoda EM, Wipf P, Greenberger JS. Pharmacologic profiling of phosphoinositide 3-kinase inhibitors as mitigators of ionizing radiation-induced cell death. J Pharmacol Exp Ther 2013; 347:669-80. [PMID: 24068833 DOI: 10.1124/jpet.113.208421] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Ionizing radiation (IR) induces genotoxic stress that triggers adaptive cellular responses, such as activation of the phosphoinositide 3-kinase (PI3K)/Akt signaling cascade. Pluripotent cells are the most important population affected by IR because they are required for cellular replenishment. Despite the clear danger to large population centers, we still lack safe and effective therapies to abrogate the life-threatening effects of any accidental or intentional IR exposure. Therefore, we computationally analyzed the chemical structural similarity of previously published small molecules that, when given after IR, mitigate cell death and found a chemical cluster that was populated with PI3K inhibitors. Subsequently, we evaluated structurally diverse PI3K inhibitors. It is remarkable that 9 of 14 PI3K inhibitors mitigated γIR-induced death in pluripotent NCCIT cells as measured by caspase 3/7 activation. A single intraperitoneal dose of LY294002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one], administered to mice at 4 or 24 hours, or PX-867 [(4S,4aR,5R,6aS,9aR,Z)-11-hydroxy-4-(methoxymethyl)-4a,6a-dimethyl-2,7,10-trioxo-1-(pyrrolidin-1-ylmethylene)-1,2,4,4a,5,6,6a,7,8,9,9a,10-dodecahydroindeno[4,5-H]isochromen-5-yl acetate (CID24798773)], administered 4 hours after a lethal dose of γIR, statistically significantly (P < 0.02) enhanced in vivo survival. Because cell cycle checkpoints are important regulators of cell survival after IR, we examined cell cycle distribution in NCCIT cells after γIR and PI3K inhibitor treatment. LY294002 and PX-867 treatment of nonirradiated cells produced a marked decrease in S phase cells with a concomitant increase in the G1 population. In irradiated cells, LY294002 and PX-867 treatment also decreased S phase and increased the G1 and G2 populations. Treatment with LY294002 or PX-867 decreased γIR-induced DNA damage as measured by γH2AX, suggesting reduced DNA damage. These results indicate pharmacologic inhibition of PI3K after IR abrogated cell death.
Collapse
Affiliation(s)
- John S Lazo
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia (J.S.L., E.R.S., A.L., S.L.); Departments of Radiation Oncology (M.W.E., J.S.G.), Chemistry (E.M.S., P.W.), and Pharmaceutical Sciences (P.W.), University of Pittsburgh, Pittsburgh, Pennsylvania
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Liu JC, Guan X, Ryan JA, Rivera AG, Mock C, Agrawal V, Agarwal V, Letai A, Lerou PH, Lahav G. High mitochondrial priming sensitizes hESCs to DNA-damage-induced apoptosis. Cell Stem Cell 2013; 13:483-91. [PMID: 23954752 DOI: 10.1016/j.stem.2013.07.018] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 06/12/2013] [Accepted: 07/24/2013] [Indexed: 12/20/2022]
Abstract
Human embryonic stem cells (hESCs) are highly sensitive to DNA damage and have low survival ability relative to differentiated cells. We investigated the source of this difference by comparing damage response pathways in hESCs and differentiated cells. We found that hESCs undergo more rapid p53-dependent apoptosis after DNA damage than differentiated cells do. However, p53 localization and function are similar between hESCs and differentiated cells, suggesting that p53 alone cannot explain the difference in sensitivity. Instead, we show that mitochondrial readiness for apoptosis, known as mitochondrial priming, differs between hESCs and differentiated cells. Specifically, the balance between proapoptotic and antiapoptotic proteins is shifted closer to the apoptotic threshold in hESCs than in differentiated cells. Altering this balance in differentiated cells increases their sensitivity and results in cell death, suggesting that manipulation of mitochondrial priming could potentially alter the sensitivity of other stem cells, including cancer stem cells.
Collapse
Affiliation(s)
- Julia C Liu
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Lessons learned about human stem cell responses to ionizing radiation exposures: a long road still ahead of us. Int J Mol Sci 2013; 14:15695-723. [PMID: 23899786 PMCID: PMC3759881 DOI: 10.3390/ijms140815695] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 07/15/2013] [Accepted: 07/17/2013] [Indexed: 12/16/2022] Open
Abstract
Human stem cells (hSC) possess several distinct characteristics that set them apart from other cell types. First, hSC are self-renewing, capable of undergoing both asymmetric and symmetric cell divisions. Second, these cells can be coaxed to differentiate into various specialized cell types and, as such, hold great promise for regenerative medicine. Recent progresses in hSC biology fostered the characterization of the responses of hSC to genotoxic stresses, including ionizing radiation (IR). Here, we examine how different types of hSC respond to IR, with a special emphasis on their radiosensitivity, cell cycle, signaling networks, DNA damage response (DDR) and DNA repair. We show that human embryonic stem cells (hESCs) possess unique characteristics in how they react to IR that clearly distinguish these cells from all adult hSC studied thus far. On the other hand, a manifestation of radiation injuries/toxicity in human bodies may depend to a large extent on hSC populating corresponding tissues, such as human mesenchymal stem cells (hMSC), human hematopoietic stem cells (hHSC), neural hSC, intestine hSC, etc. We discuss here that hSC responses to IR differ notably across many types of hSC which may represent the distinct roles these cells play in development, regeneration and/or maintenance of homeostasis.
Collapse
|
21
|
Rebuzzini P, Fassina L, Mulas F, Bellazzi R, Redi CA, Di Liberto R, Magenes G, Adjaye J, Zuccotti M, Garagna S. Mouse embryonic stem cells irradiated with γ-rays differentiate into cardiomyocytes but with altered contractile properties. Mutat Res 2013; 756:37-45. [PMID: 23792212 DOI: 10.1016/j.mrgentox.2013.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 12/15/2022]
Abstract
Embryonic stem cells (ESCs) for their derivation from the inner cell mass of a blastocyst represent a valuable in vitro model to investigate the effects of ionizing radiation on early embryonic cellular response. Following irradiation, both human and mouse ESCs (mESCs) maintain their pluripotent status and the capacity to differentiate into embryoid bodies and to form teratomas. Although informative of the maintenance of a pluripotent status, these studies never investigated the capability of irradiated ESCs to form specific differentiated phenotypes. Here, for the first time, 5Gy-irradiated mESCs were differentiated into cardiomyocytes, thus allowing the analysis of the long-term effects of ionizing radiations on the differentiation potential of a pluripotent stem cell population. On treated mESCs, 96h after irradiation, a genome-wide expression analysis was first performed in order to determine whether the treatment influenced gene expression of the surviving mESCs. Microarrays analysis showed that only 186 genes were differentially expressed in treated mESCs compared to control cells; a quarter of these genes were involved in cellular differentiation, with three main gene networks emerging, including cardiogenesis. Based on these results, we differentiated irradiated mESCs into cardiomyocytes. On day 5, 8 and 12 of differentiation, treated cells showed a significant alteration (qRT-PCR) of the expression of marker genes (Gata-4, Nkx-2.5, Tnnc1 and Alpk3) when compared to control cells. At day 15 of differentiation, although the organization of sarcomeric α-actinin and troponin T proteins appeared similar in cardiomyocytes differentiated from either mock or treated cells, the video evaluation of the kinematics and dynamics of the beating cardiac syncytium evidenced altered contractile properties of cardiomyocytes derived from irradiated mESCs. This alteration correlated with significant reduction of Connexin 43 foci. Our results indicate that mESCs populations that survive an ionizing irradiation treatment are capable to differentiate into cardiomyocytes, but they have altered contractile properties.
Collapse
Affiliation(s)
- Paola Rebuzzini
- Laboratorio di Biologia dello Sviluppo, Dipartimento di Biologia e Biotecnologie 'Lazzaro Spallanzani', Università degli Studi di Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Human embryonic stem cell responses to ionizing radiation exposures: current state of knowledge and future challenges. Stem Cells Int 2012; 2012:579104. [PMID: 22966236 PMCID: PMC3431129 DOI: 10.1155/2012/579104] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 07/22/2012] [Indexed: 01/27/2023] Open
Abstract
Human embryonic stem cells, which are derived from the inner cell mass of the blastocyst, have become an object of intense study over the last decade. They possess two unique properties that distinguish them from many other cell types: (i) the ability to self-renew indefinitely in culture under permissive conditions, and (ii) the pluripotency, defined as the capability of giving rise to all cell types of embryonic lineage under the guidance of the appropriate developmental cues. The focus of many recent efforts has been on the elucidating the signaling pathways and molecular networks operating in human embryonic stem cells. These cells hold great promise in cell-based regenerative therapies, disease modeling, drug screening and testing, assessing genotoxic and mutagenic risks associated with exposures to a variety of environmental factors, and so forth. Ionizing radiation is ubiquitous in nature, and it is widely used in diagnostic and therapeutic procedures in medicine. In this paper, our goal is to summarize the recent progress in understanding how human embryonic stem cells respond to ionizing radiation exposures, using novel methodologies based on “omics” approaches, and to provide a critical discussion of what remains unknown; thus proposing a roadmap for the future research in this area.
Collapse
|
23
|
Panyutin IV, Eniafe R, Panyutin IG, Neumann RD. Effect of 5-[(125)I]iodo-2'-deoxyuridine uptake on the proliferation and pluripotency of human embryonic stem cells. Int J Radiat Biol 2012; 88:954-60. [PMID: 22676300 DOI: 10.3109/09553002.2012.700435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE Human embryonic stem cells (hESC) hold a great potential for regenerative medicine because, in principle, they can differentiate into any cell type found in the human body. In addition, studying the effect of ionizing radiation (IR) on hESC may provide valuable information about the response of human cells to IR exposure in their most naive state, as well as the consequences of IR exposure on the development of organisms. However, the effect of IR, in particular radionuclide uptake, on the pluripotency, proliferation and survival of hESC has not been extensively studied. METHODS In this study we treated cultured hESC with 5-[(125)I]iodo-2'-deoxyuridine ((125)IdU), a precursor of DNA synthesis. Then we measured the expansion of colonies and expression of pluripotency markers in hESC. RESULTS We found that uptake of (125)IdU was similar in both hESC and HT1080 human fibrosarcoma cells. However, treatment with 0.1 μCi/ml (125)IdU for 24 hours resulted in complete death of the hESC population; whereas HT1080 cancer cells continued to grow. Treatment with a 10-fold lower dose (125)IdU (0.01 μCi/ml) resulted in colonies of hESC becoming less defined with numerous cells growing in monolayer outside of the colonies showing signs of differentiation. Then we analyzed the expression of pluripotency markers (octamer-binding transcription factor 4 [Oct-4] and stage-specific embryonic antigen-4 [SSEA4]) in the surviving hESC. We found that hESC in the surviving colonies expressed pluripotency markers at levels comparable with those in the non-treated controls. CONCLUSIONS Our results provide important initial insights into the sensitivity of hESC to IR, and especially that produced by the decay of an internalized radionuclide.
Collapse
Affiliation(s)
- Irina V Panyutin
- Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | |
Collapse
|
24
|
van Bergeijk P, Heimiller J, Uyetake L, Su TT. Genome-wide expression analysis identifies a modulator of ionizing radiation-induced p53-independent apoptosis in Drosophila melanogaster. PLoS One 2012; 7:e36539. [PMID: 22666323 PMCID: PMC3362589 DOI: 10.1371/journal.pone.0036539] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 04/09/2012] [Indexed: 12/20/2022] Open
Abstract
Tumor suppressor p53 plays a key role in DNA damage responses in metazoa, yet more than half of human tumors show p53 deficiencies. Therefore, understanding how therapeutic genotoxins such as ionizing radiation (IR) can elicit DNA damage responses in a p53-independent manner is of clinical importance. Drosophila has been a good model to study the effects of IR because DNA damage responses as well as underlying genes are conserved in this model, and because streamlined gene families make loss-of-function analyses feasible. Indeed, Drosophila is the only genetically tractable model for IR-induced, p53-independent apoptosis and for tissue regeneration and homeostasis after radiation damage. While these phenomenon occur only in the larvae, all genome-wide gene expression analyses after irradiation to date have been in embryos. We report here the first analysis of IR-induced, genome-wide gene expression changes in wild type and p53 mutant Drosophila larvae. Key data from microarrays were confirmed by quantitative RT-PCR. The results solidify the central role of p53 in IR-induced transcriptome changes, but also show that nearly all changes are made of both p53-dependent and p53-independent components. p53 is found to be necessary not just for the induction of but also for the repression of transcript levels for many genes in response to IR. Furthermore, Functional analysis of one of the top-changing genes, EF1a-100E, implicates it in repression of IR-induced p53-independent apoptosis. These and other results support the emerging notion that there is not a single dominant mechanism but that both positive and negative inputs collaborate to induce p53-independent apoptosis in response to IR in Drosophila larvae.
Collapse
Affiliation(s)
- Petra van Bergeijk
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Joseph Heimiller
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Lyle Uyetake
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Tin Tin Su
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, United States of America
- * E-mail:
| |
Collapse
|
25
|
Sokolov MV, Panyutin IV, Neumann RD. Unraveling the global microRNAome responses to ionizing radiation in human embryonic stem cells. PLoS One 2012; 7:e31028. [PMID: 22347422 PMCID: PMC3275573 DOI: 10.1371/journal.pone.0031028] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 12/31/2011] [Indexed: 01/07/2023] Open
Abstract
MicroRNAs (miRNA) comprise a group of short ribonucleic acid molecules implicated in regulation of key biological processes and functions at the post-transcriptional level. Ionizing radiation (IR) causes DNA damage and generally triggers cellular stress response. However, the role of miRNAs in IR-induced response in human embryonic stem cells (hESC) has not been defined yet. Here, by using system biology approaches, we show for the first time, that miRNAome undergoes global alterations in hESC (H1 and H9 lines) after IR. Interrogation of expression levels of 1,090 miRNA species in irradiated hESC showed statistically significant changes in 54 genes following 1 Gy of X-ray exposures; global miRNAome alterations were found to be highly temporally and cell line - dependent in hESC. Time-course studies showed that the 16 hr miRNAome radiation response of hESC is much more robust compared to 2 hr-response signature (only eight genes), and may be involved in regulating the cell cycle. Quantitative real-time PCR performed on some miRNA species confirms the robustness of our miRNA microarray platform. Positive regulation of differentiation-, cell cycle-, ion transport- and endomembrane system-related processes were predicted to be negatively affected by miRNAome changes in irradiated hESC. Our findings reveal a fundamental role of miRNAome in modulating the radiation response, and identify novel molecular targets of radiation in hESC.
Collapse
Affiliation(s)
- Mykyta V Sokolov
- Nuclear Medicine Division, Department of Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America.
| | | | | |
Collapse
|
26
|
Suvorova II, Katolikova NV, Pospelov VA. New insights into cell cycle regulation and DNA damage response in embryonic stem cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 299:161-98. [PMID: 22959303 DOI: 10.1016/b978-0-12-394310-1.00004-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Embryonic stem cells (ESCs) have unlimited proliferative potential, while retaining the ability to differentiate into descendants of all three embryonic layers. High proliferation rate of ESCs is accompanied by a shortening of the G(1) phase and the lack of G(1) checkpoint following DNA damage. The absence of G(1) arrest in ESCs after DNA damage is likely caused by a dysfunction of the p53-dependent p21Waf1 pathway that is a key event for the maintenance of pluripotency. There are controversial data on the functional status of p53, but it is well established that one of the key p53 target-p21Waf1-is expressed in ESCs at a very low level. Despite the lack of G(1) checkpoint, ESCs are capable to repair DNA defects; moreover the DNA damage response (DDR) signaling operates very effectively throughout the cell cycle. This review covers also the results obtained with the reprogramming of somatic cells into the induced pluripotent stem cells, for which have been shown that a partial dysfunction of the p53Waf1 pathway increases the frequency of generation of pluripotent cells. In summary, these results indicate that the G(1) checkpoint control and DDR are distinct from somatic cells and their status is tightly connected with maintaining of pluripotency and self-renewal.
Collapse
Affiliation(s)
- Irina I Suvorova
- Institute of Cytology, Russian Academy of Sciences, St Petersburg, Russia
| | | | | |
Collapse
|