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Xu B, Gao X, Li X, Jia Y, Li F, Zhang Z. Cell cycle arrest explains the observed bulk 3D genomic alterations in response to long-term heat shock in K562 cells. Genome Res 2022; 32:1285-1297. [PMID: 35835565 PMCID: PMC9341516 DOI: 10.1101/gr.276554.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 06/13/2022] [Indexed: 01/03/2023]
Abstract
Heat shock is a common environmental stress, although the response of the nucleus to it remains controversial in mammalian cells. Acute reaction and chronic adaptation to environmental stress may have distinct internal rewiring in the gene regulation networks. However, this difference remains largely unexplored. Here, we report that chromatin conformation and chromatin accessibility respond differently in short- and long-term heat shock in human K562 cells. We found that chromatin conformation in K562 cells was largely stable in response to short-term heat shock, whereas it showed clear and characteristic changes after long-term heat treatment with little alteration in chromatin accessibility during the whole process. We further show in silico and experimental evidence strongly suggesting that changes in chromatin conformation may largely stem from an accumulation of cells in the M stage of the cell cycle in response to heat shock. Our results represent a paradigm shift away from the controversial view of chromatin response to heat shock and emphasize the necessity of cell cycle analysis when interpreting bulk Hi-C data.
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Affiliation(s)
- Bingxiang Xu
- Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Chaoyang District, Beijing 100101, China;,School of Life Science, University of Chinese Academy of Sciences, Beijing 101408, China;,School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China
| | - Xiaomeng Gao
- Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Chaoyang District, Beijing 100101, China;,School of Life Science, University of Chinese Academy of Sciences, Beijing 101408, China
| | - Xiaoli Li
- Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Chaoyang District, Beijing 100101, China;,School of Life Science, University of Chinese Academy of Sciences, Beijing 101408, China;,Department of Cell Biology and Genetics, Core Facility of Developmental Biology, Chongqing Medical University, Chongqing 400016, China
| | - Yan Jia
- Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Chaoyang District, Beijing 100101, China
| | - Feifei Li
- Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Chaoyang District, Beijing 100101, China;,Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China
| | - Zhihua Zhang
- Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Chaoyang District, Beijing 100101, China;,School of Life Science, University of Chinese Academy of Sciences, Beijing 101408, China
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Andreeva NV, Zatsepina OG, Garbuz DG, Evgen'ev MB, Belyavsky AV. Recombinant HSP70 and mild heat shock stimulate growth of aged mesenchymal stem cells. Cell Stress Chaperones 2016; 21:727-33. [PMID: 27091568 PMCID: PMC4907997 DOI: 10.1007/s12192-016-0691-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/25/2016] [Accepted: 04/11/2016] [Indexed: 01/21/2023] Open
Abstract
Heat shock proteins including the major stress protein HSP70 support intracellular homeostasis and prevent protein damage after a temperature increase and other stressful environmental stimuli, as well as during aging. We have shown earlier that prolonged administration of recombinant human HSP70 to mice exhibiting Alzheimer's-like neurodegeneration as well as during sepsis reduces the clinical manifestations of these pathologies. Herein, we studied the action of recombinant human HSP70 on young and aged mouse mesenchymal stem cells (MSCs) in culture. The results obtained indicate that HSP70 at concentrations of 2 μg/ml and higher significantly stimulates growth of aged but not young MSCs. A similar effect is produced by application of a mild heat shock (42 °C 5 min) to the cells. Importantly, responses of young and aged MSCs to heat shock treatment of various durations differed drastically, and aged MSCs were significantly more sensitive to higher heat stress exposures than the young cells. Western blotting and protein labeling experiments demonstrated that neither mild heat shock nor exogenous HSP70 administration resulted in significant endogenous HSP70 induction in young and aged MSCs, whereas mild heat shock increased HSC70 levels in aged MSCs. The results of this study suggest that the administration of exogenous HSP70 and the application of mild heat stress may produce a certain "rejuvenating" effect on MSCs and possibly other cell types in vivo, and these interventions may potentially be used for life extension by delaying various manifestations of aging at the molecular and cellular level.
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Affiliation(s)
- N V Andreeva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Vavilov Str. 32, Russian Federation
| | - O G Zatsepina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Vavilov Str. 32, Russian Federation
| | - D G Garbuz
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Vavilov Str. 32, Russian Federation
| | - M B Evgen'ev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Vavilov Str. 32, Russian Federation.
| | - A V Belyavsky
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Vavilov Str. 32, Russian Federation
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3
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Bouhon IA, Ito A, Shinkai M, Honda H, Kobayashi T. Heat induction of reporter gene expression via the gadd153 promoter and its possible application to hyperthermia treatment of cancer. Cytotechnology 2011; 33:131-7. [PMID: 19002820 DOI: 10.1023/a:1008181600197] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The use of the gadd153promoter to induce expression of a reporter geneunder heat stress conditions was investigated,since the results of previous studies have suggestedthat the gadd153promoter is likely to be activated by the indirecteffects of hyperthermia, that is, by DNA damage thatoccurs when reactive oxygen species are produced byheat stress. The optimum temperature for a significantinduction was found to be between 41 and 43 degrees C andincreased expression of the reporter gene was observedat about 24 h after the heat treatment. Under theseconditions, the cell integrity was not alteredmorphologically and the growth stopped temporarily,while the viability was maintained. A second increasein expression occurred at a later stage when the cellswere severely damaged at 43-45 degrees C. Atthese temperatures, the cellular morphology showedsignificant alteration and the growth was stronglyarrested. This is likely to be due to a differentmechanism which could involve DNA repair processes. Itis expected that this method of induction can beexploited to drive the production of a protein ofinterest in a cancer treatment program that includes hyperthermia.
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Affiliation(s)
- I A Bouhon
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
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4
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Maurel A, Azarnoush K, Sabbah L, Vignier N, Le Lorc'h M, Mandet C, Bissery A, Garcin I, Carrion C, Fiszman M, Bruneval P, Hagege A, Carpentier A, Vilquin JT, Menasché P. Can cold or heat shock improve skeletal myoblast engraftment in infarcted myocardium? Transplantation 2005; 80:660-5. [PMID: 16177642 DOI: 10.1097/01.tp.0000172178.35488.31] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Cell death remains a major limitation of skeletal myoblast (SM) transplantation but the patterns of cell survival and proliferation in heart and their potential modulation by thermic stresses like heat shock (HS) and cryopreservation (Cryo) are still incompletely characterized. METHODS To track SMs in situ, we developed a dual-marker system based on the semiconservative expression of the foreign soluble protein, beta-Galactosidase (beta-Gal) and the constitutive expression of the Y chromosome in a myocardial infarction model. Control medium or Lewis male rat SMs (fresh or subjected to Cryo or HS) were injected in Lewis female rats. RESULTS There was a massive cell loss early after transplantation in the fresh group, which was only partially compensated for by a subsequent proliferation. Conversely, both Cryo and HS significantly improved early cell survival but blunted subsequent proliferation so that, at 15 days posttransplantation, the total number of engrafted donor-derived Y-positive cells did not differ significantly between the three groups. Most of them expressed a skeletal muscle phenotype. CONCLUSIONS These data confirm the high death rate of in-scar transplanted myoblasts, demonstrate the ability of those that survive to proliferate and differentiate along the myogenic pathway but do not support the efficacy of either Cryo or HS for increasing the ultimate magnitude of myoblast engraftment.
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Affiliation(s)
- Agnès Maurel
- 1 INSERM U633, Laboratoire d'Etude des Greffes et Prothèses Cardiaques, Hôpital Broussais, Paris, France
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5
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Kühl NM, Kunz J, Rensing L. Heat shock-induced arrests in different cell cycle phases of rat C6-glioma cells are attenuated in heat shock-primed thermotolerant cells. Cell Prolif 2002; 33:147-66. [PMID: 10959624 PMCID: PMC6496355 DOI: 10.1046/j.1365-2184.2000.00175.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The response kinetics of rat C6 glioma cells to heat shock was investigated by means of flow cytometric DNA measurements and western blot analysis of HSP levels. The results showed that the effects on cell cycle progression are dependent on the cell cycle phase at which heat shock is applied, leading to either G1 or G2/M arrest in randomly proliferating cells. When synchronous cultures were stressed during G0 they were arrested with G1 DNA content and showed prolongation of S and G2 phases after release from the block. In proliferating cells, HSC70 and HSP68 were induced during the recovery and reached maximum levels just before cells were released from the cell cycle blocks. Hyperthermic pretreatment induced thermotolerance both in asynchronous and synchronous cultures as evidenced by the reduced arrest of cell cycle progression after the second heat shock. Thermotolerance development was independent of the cell cycle phase. Pre-treated cells already had high HSP levels and did not further increase the amount of HSP after the second treatment. However, as in unprimed cells, HSP reduction coincided with the release from the cell cycle blocks. These results imply that the cell cycle machinery can be rendered thermotolerant by heat shock pretreatment and supports the assumption that HSP70 family members might be involved in thermotolerance development.
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Affiliation(s)
- N M Kühl
- Institute of Cell Biology, Biochemistry and Biotechnology, University of Bremen, Germany
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Khandjian EW, Rose TM. Disruption of LT-antigen/p53 complex by heat treatment correlates with inhibition of DNA synthesis during transforming infection with SV40. Biochem Cell Biol 2000. [DOI: 10.1139/o00-013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Transforming infection of Go/G1-arrested primary mouse kidney cell cultures with simian virus 40 (SV40) induces cells to re-enter the S-phase of the cell cycle. In Go-arrested cells, no p53 is detected, whereas in cells induced to proliferate by infection, a gradual accumulation of p53 complexed to SV40 large T-antigen is observed in the nucleus. Heat treatment of actively proliferating SV40-infected cells leads to inhibition of DNA synthesis and growth arrest. To determine the fate of p53 after heat treatment, proliferating infected cells were exposed to mild heat (42.5°C) for increasing lengths of time. The results presented here show that after ninety minutes of treatment, the arrest of DNA synthesis by heat correlates with the disruption of the p53/LT-antigen complex. Longer treatments induce, in addition, a reduction in the solubility of p53, which was recovered tightly associated with the nuclear fraction. This contrasted with large T-antigen, whose solubility remained unaffected by heat treatment. Although the total amount of p53 in the nucleus remained constant, as shown by immunoblot analyses, p53 was no longer detectable after immunoprecipitation or by immunofluorescent staining techniques. These results suggest that heat treatment had either induced conformational changes in its antigenic sites, or had sequestered the sites through aggregation or binding to insoluble nuclear components.Key words: p53, heat shock, LT-antigen/p53 complex, S-phase.
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7
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Simons JW. A theory on cellular aging and cell immortalization. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 1999; 24:1-21. [PMID: 10547856 DOI: 10.1007/978-3-662-06227-2_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- J W Simons
- Department of Radiation Genetics and Chemical Mutagenesis, MGC, Leiden University, The Netherlands
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8
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Wang Z, Lindquist S. Developmentally regulated nuclear transport of transcription factors in Drosophila embryos enable the heat shock response. Development 1998; 125:4841-50. [PMID: 9806932 DOI: 10.1242/dev.125.23.4841] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hsp70 is a broadly conserved thermotolerance factor, but inhibits growth at normal temperatures and cannot be induced in early embryos. We report that in Drosophila embryos the temporal and spatial patterns of Hsp70 inducibility were unexpectedly complex, with striking differences between the soma and the germline. In both, regulation occurred at the level of transcription. During the refractory period for Hsp70 induction, HSF (heat-shock transcription factor) exhibited specific DNA-binding activity characteristic of activation in extracts of heated embryos. Remarkably, however, HSF was restricted to the cytoplasm in intact embryos even after heat shock. HSF moved from the cytoplasm to the nucleus in the absence of heat precisely when the capacity to induce Hsp70 was acquired (cycle 12 of the germline, cycle 13 in the soma). During oogenesis, Hsp70 inducibility was lost in nurse cells around stage 10, in a posterior-to-anterior gradient and HSF redistributed from nucleus to cytoplasm in the same spatiotemporal pattern. In a highly inbred derivative of the Samarkind strain, HSF moved into embryonic nuclei earlier than in our standard wild-type strain. Correspondingly, Hsp70 was inducible earlier, confirming that nuclear transport of HSF controls the inducibility of Hsp70 in early embryos. We also report for the first time the nuclear import patterns of two general transcription factors, RNA polymerase subunit Ilc and TATA binding protein (TBP). Both enter nuclei in a highly synchronous manner, independently of each other and of HSF. The import of TBP coincides with the first reported appearance of transcripts in the embryo. We suggest that the potentiation of general and heat shock-specific transcription in Drosophila embryos is controlled by the developmentally programmed relocalization of general and heat shock-specific transcription factors. Restricted nuclear entry of HSF represents a newly described mechanism for regulating the heat-shock response.
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Affiliation(s)
- Z Wang
- Committee on Developmental Biology, The University of Chicago, Chicago, IL 60637, USA
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9
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Valenzuela MT, Núñez MI, Villalobos M, Siles E, McMillan TJ, Pedraza V, Ruiz de Almodóvar JM. A comparison of p53 and p16 expression in human tumor cells treated with hyperthermia or ionizing radiation. Int J Cancer 1997; 72:307-12. [PMID: 9219838 DOI: 10.1002/(sici)1097-0215(19970717)72:2<307::aid-ijc18>3.0.co;2-c] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To assess the potential relationship between p53 and p16 proteins in the cellular response to stress, we have examined the levels of these proteins in a series of human tumor cell lines after treatment with either ionizing radiation or hyperthermia. We found that cells with abnormal radiation-induced G1 arrest (non-functional p53) had significantly higher constitutive levels of p16 than cells showing a normal G1 arrest (functional p53). Time-course experiments were done to test the effect of gamma-irradiation on intracellular levels of p16. The pattern of changes in p16 response was similar in all cell lines studied, and p16 expression was not related to cellular sensitivity to radiation or to the level of p53 induction after treatment. We also provide evidence that short-term exposure to high temperature causes p53 accumulation. Hyperthermia-induced p53 accumulation was greatest in those cells exhibiting the highest radiation-induced p53 accumulation, suggesting a possible relationship between p53 induction after these 2 different stresses. p16 synthesis was also induced in different cell lines after heat treatment, and this response was independent of p53 functionality. When we compared the level of p16 expression with the extent of G0/G1 arrest induced by heat, a linear correlation was found, raising the possibility that p16 may be involved in the control of cell cycle progression in response to heat treatment.
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Affiliation(s)
- M T Valenzuela
- Departamento de Radiología y Medicina Física, Facultad de Medicina, Universidad de Granada, Spain
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10
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Tucci M, Hammerman SI, Furfaro S, Saukonnen JJ, Conca TJ, Farber HW. Distinct effect of hypoxia on endothelial cell proliferation and cycling. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 272:C1700-8. [PMID: 9176162 DOI: 10.1152/ajpcell.1997.272.5.c1700] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Endothelial cells (EC) occupy a strategic location in the vasculature as a barrier between the intravascular compartment and underlying tissues; as such, they are often exposed to stresses, such as decreases in ambient oxygen, diminished metabolic substrate, or changes in temperature, that could affect their ability to divide and proliferate. The present study characterizes cell counts, cell cycle distribution, and bromodeoxyuridine incorporation in pulmonary artery and aortic EC exposed to acute and/or chronic hypoxia and other cellular stresses. During hypoxia, EC division slows but does not arrest; progression through the G1-to-S transition point and/or progression from S to G2/M is altered with an increased percent of EC in S phase. These changes in EC cell cycle distribution with hypoxia are dependent on the origin of the EC as well as the ambient oxygen concentration; moreover, they are distinct from changes observed with elevated temperature or glucose deprivation. and differ from the quiescent pattern induced by serum deprivation or high-density confluence. These findings demonstrate that hypoxia exerts a distinct effect on the cell cycle distribution and proliferation of EC.
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Affiliation(s)
- M Tucci
- Pulmonary Center, Boston University School of Medicine, Massachusetts 02118, USA
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11
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Vilaboa NE, García-Bermejo L, Pérez C, de Blas E, Calle C, Aller P. Heat-shock and cadmium chloride increase the vimentin mRNA and protein levels in U-937 human promonocytic cells. J Cell Sci 1997; 110 ( Pt 2):201-7. [PMID: 9044050 DOI: 10.1242/jcs.110.2.201] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heat-shock for 2 hours at 42 degrees C, or the administration for 3 hours of 100 or 150 microM cadmium chloride, inhibited the subsequent proliferation activity, induced the expression of functional differentiation markers, and caused an increase in the amount of the stress-responsive HSP70 protein in U-937 human promonocytic cells. In addition, both heat and cadmium produced an increase in the amount of the intermediate filament protein vimentin, as determined by immunoblot and immunofluorescence assays. By contrast, the amounts of actin and beta-tubulin were not significantly altered. The amount of vimentin mRNA was also increased during recovery from stress, indicating that vimentin expression was not exclusively regulated at the protein level. Although cadmium caused an early, transient stimulation of c-jun and c-fos expression and AP-1 binding activity, heat-shock failed to alter both protooncogene expression and transcription factor binding, indicating that the stress-induced vimentin increase was not the result of AP-1-mediated transcriptional activation. Finally, it was observed that the rate of decay of vimentin mRNA upon actinomycin D administration was decreased in heat- and cadmium-pretreated cells in comparison to untreated cells. These results indicate that stress treatments cause an increase in vimentin levels in promonocytic cells, which may be explained at least in part by transcript stabilization.
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Affiliation(s)
- N E Vilaboa
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
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12
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Vilaboa NE, Calle C, Pérez C, de Blas E, García-Bermejo L, Aller P. cAMP increasing agents prevent the stimulation of heat-shock protein 70 (HSP70) gene expression by cadmium chloride in human myeloid cell lines. J Cell Sci 1995; 108 ( Pt 8):2877-83. [PMID: 7593327 DOI: 10.1242/jcs.108.8.2877] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Treatment of U-937 human promonocytic cells with the cAMP increasing agents isoproterenol plus theophylline decreased the basal level of heat-shock protein 70 (HSP70) mRNA. In addition, the cAMP increasing agents attenuated the increase in HSP70 mRNA and protein levels produced by cadmium chloride in U-937 and other human myeloid cell lines, reduced the capacity of cadmium treatment to generate stress-tolerance, and attenuated the cadmium-produced stimulation of heat-shock factor (HSF) binding activity. By contrast, isoproterenol plus theophylline failed to attenuate the stimulation of HSP70 gene expression and HSF binding activity caused by heat-shock. Isoproterenol plus theophylline did not prevent the uptake of cadmium into the cells, and increased to a similar extent the intracellular cAMP levels in cadmium- and heat-treated cells. The cAMP increasing agents reduced the induction by cadmium of the HSP27 stress gene, but failed to attenuate other cadmium-elicited stress reactions such as the inhibition of total protein synthesis. It is concluded that cAMP does not inhibit the stress response as a whole, but it interferes with some step of the pathway by which cadmium specifically stimulates HSF binding activity and as a consequence HSP70 gene expression, in human myeloid cell lines.
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Affiliation(s)
- N E Vilaboa
- Centro de Investigaciones Biológicas, CSIC, Velázquez, Madrid, Spain
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13
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Higashikubo R, Goswami PC, Roti JLR. A comparison of time-lapse cinemicrography and flow cytometry for the study of accelerated cell-cycle transit. Cell Prolif 1994. [DOI: 10.1111/j.1365-2184.1994.tb01385.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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14
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Control of growth and recombinant protein synthesis by heat-shock in a mutant mammalian cell line. Biotechnol Lett 1994. [DOI: 10.1007/bf00134614] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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15
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Higashikubo R, White RA, Roti Roti JL. Flow cytometric BrdUrd-pulse-chase study of heat-induced cell-cycle progression delays. Cell Prolif 1993; 26:337-48. [PMID: 8343562 DOI: 10.1111/j.1365-2184.1993.tb00329.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The flow cytometric, bromodeoxyuridine (BrdUrd)-pulse-chase method was extended by analysing five kinetic parameters to study perturbed cell progression through the cell cycle. The method was used to analyse the cell-cycle perturbations induced by heat shock. Exponentially growing, asynchronous Chinese hamster ovary (CHO) cells were pulse labelled with BrdUrd and simultaneously heated at 43 degrees C for 5, 10 or 15 min. The cells were then incubated in a BrdUrd-free medium and, at various times thereafter, were prepared for flow cytometry. Five compartments (BrdUrd-labelled divided and undivided, and unlabelled G1, G1S, and G2) were defined in the resulting dual-parameter histograms. The fraction of cells and the mean DNA content, when appropriate, were calculated for each compartment. The rates of cell-cycle progression were assessed as time-dependent changes in the fraction of cells in a given compartment and/or the relative DNA content of cells within a given compartment. Linear regression analysis of the data revealed two distinct modes of alteration in cell progression: 1 a delay in cell transit (either out of or into a given compartment), and 2 a decrease in the rate of cell transit. Hyperthermia produced a delay in the exit of cells from the G1 compartment of approximately 16 min per minute of heat at 43 degrees C with no threshold. In contrast, the delay in the exit of cells from all other compartments showed a threshold of from 3 to 5 min at 43 degrees C. Above this threshold the delay in exit of cells from the BrdUrd-labelled, undivided compartment was approximately 25 min per minute of heat at 43 degrees C. The more complex dose-response function of this latter compartment may reflect the fact that it includes two cell-cycle phases, S and G2 + M. The decrease in the rate of transit out of G2 for cells heated in G2 was significantly larger than that for any other compartment, consistent with previous studies, which showed a G2 accumulation following hyperthermia. These results indicate that heat exposure induces very complex alterations in cell-cycle progression and that this flow cytometric method offers a straightforward approach for observing such alterations.
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Affiliation(s)
- R Higashikubo
- Section of Cancer Biology, Washington University Medical Center, St Louis, MO 63108
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16
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17
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Walsh D, Li K, Wass J, Dolnikov A, Zeng F, Zhe L, Edwards M. Heat-shock gene expression and cell cycle changes during mammalian embryonic development. DEVELOPMENTAL GENETICS 1993; 14:127-36. [PMID: 8482017 DOI: 10.1002/dvg.1020140207] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Synchronized regulation of cell division during gastrulation is essential for the regional proliferation of cells and pattern formation of the early CNS. The neural plate and neuroectoderm cells are a rapidly dividing and differentiating population of cells with a unique and rapid heat-shock response. Heat shock and the heat-shock genes were studied during neural plate development in a whole rat embryo culture system at 9.5-11.5 days. A lethal shock can cause cell death and severe developmental defects to the forebrain and eye during organogenesis. Heat shock can also result in acquired thermotolerance whereby cell progression is delayed at the G1/S and S/G2 boundaries of the cell cycle. This delay in cell cycle progression caused an overall lengthening of the cell cycle time of at least 2 hr. The heat shock genes may therefore function as cell cycle regulators in neuroectoderm induction and differentiation. The kinetics and expression of the hsp genes were examined in neuroectodermal cells by flow cytometry and Northern analysis. The levels of hsp mRNA 27, 71, 73, and 88 were identified following exposure at 42 degrees C (nonlethal), 43 degrees C (lethal) and 42 degrees/43 degrees C (thermotolerant) heat shock. Examination of hsp gene expression in the neural plate showed tight regulation in the cell cycle phases. Hsp 88 expression was enhanced at Go and hsp71 induction at G2 + M of the cell cycle. Cells exposed to a thermotolerant heat shock of 42 degrees C induced hsp71 mRNA expression in all phases of the cell cycle with the mRNA levels of hsp27, 73, and 88 increased but relatively constant. Following a lethal heat shock, dramatic changes in hsp expression were seen especially enhanced hsp71 induction in late S phase. The regulated expression of hsps during the cell cycle at various phases could play a unique and important role in the fate and recovery of neuroectoderm cells during early mammalian embryo development.
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Affiliation(s)
- D Walsh
- Department of Veterinary Clinical Sciences, University of Sydney, New South Wales, Australia
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18
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Affiliation(s)
- R H Burdon
- Department of Bioscience and Biotechnology, University of Strathclyde, Glasgow, Scotland
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