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Zhang SX, Wang DL, Qi JJ, Yang YW, Sun H, Sun BX, Liang S. Chlorogenic acid ameliorates the heat stress-induced impairment of porcine Sertoli cells by suppressing oxidative stress and apoptosis. Theriogenology 2024; 214:148-156. [PMID: 37875054 DOI: 10.1016/j.theriogenology.2023.10.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 10/13/2023] [Accepted: 10/15/2023] [Indexed: 10/26/2023]
Abstract
Sertoli cells are an important type of somatic cell in the testis that are in direct contact with spermatogonia in vivo and play an important role in the process of spermatogenesis. Chlorogenic acid (CGA) plays a pivotal role in the regulation of the mammalian cell heat stress response. For example, CGA treatment protects porcine oocytes from heat stress-induced apoptosis and prevents reduced embryo quality. However, the role of CGA treatment in protecting porcine testicular Sertoli cells against heat-induced damage has rarely been studied. This study aimed to identify the protective effects of CGA on oxidative stress and apoptosis in Sertoli cells under heat stress. The present results demonstrated that the addition of CGA significantly inhibited the accumulation of reactive oxygen species (ROS) and apoptosis in Sertoli cells induced by heat stress and decreased the expression of CASP3 protein and the BAX/BCL-2 protein ratio. CGA pretreatment also prevented the heat stress-induced reductions in the mitochondrial membrane potential, PCNA protein expression, and SOD and CAT activities. Moreover, CGA treatment reversed S phase cell cycle arrest and increased the HSP70 protein expression levels. Overall, these results suggest that oxidative damage participates in the inhibition of the proliferation of Sertoli cells and the increase in their apoptosis induced by heat stress, and the protective effects of CGA treatment on Sertoli cells under heat stress provide a theoretical basis for preventing heat stress injury in animals.
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Affiliation(s)
- Shao-Xuan Zhang
- Department of Animals Sciences, College of Animal Sciences, Jilin University, Changchun, China
| | - Da-Li Wang
- Department of Animals Sciences, College of Animal Sciences, Jilin University, Changchun, China
| | - Jia-Jia Qi
- Department of Animals Sciences, College of Animal Sciences, Jilin University, Changchun, China
| | - Yu-Wei Yang
- Department of Animals Sciences, College of Animal Sciences, Jilin University, Changchun, China
| | - Hao Sun
- Department of Animals Sciences, College of Animal Sciences, Jilin University, Changchun, China
| | - Bo-Xing Sun
- Department of Animals Sciences, College of Animal Sciences, Jilin University, Changchun, China.
| | - Shuang Liang
- Department of Animals Sciences, College of Animal Sciences, Jilin University, Changchun, China.
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Gleason LU, Fekete FJ, Tanner RL, Dowd WW. Multi-omics reveals largely distinct transcript- and protein-level responses to the environment in an intertidal mussel. J Exp Biol 2023; 226:jeb245962. [PMID: 37902141 PMCID: PMC10690110 DOI: 10.1242/jeb.245962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 10/12/2023] [Indexed: 10/31/2023]
Abstract
Organismal responses to stressful environments are influenced by numerous transcript- and protein-level mechanisms, and the relationships between expression changes at these levels are not always straightforward. Here, we used paired transcriptomic and proteomic datasets from two previous studies from gill of the California mussel, Mytilus californianus, to explore how simultaneous transcript and protein abundance patterns may diverge under different environmental scenarios. Field-acclimatized mussels were sampled from two disparate intertidal sites; individuals from one site were subjected to three further treatments (common garden, low-intertidal or high-intertidal outplant) that vary in temperature and feeding time. Assessing 1519 genes shared between the two datasets revealed that both transcript and protein expression patterns differentiated the treatments at a global level, despite numerous underlying discrepancies. There were far more instances of differential expression between treatments in transcript only (1451) or protein only (226) than of the two levels shifting expression concordantly (68 instances). Upregulated expression of cilium-associated transcripts (likely related to feeding) was associated with relatively benign field treatments. In the most stressful treatment, transcripts, but not proteins, for several molecular chaperones (including heat shock proteins and endoplasmic reticulum chaperones) were more abundant, consistent with a threshold model for induction of translation of constitutively available mRNAs. Overall, these results suggest that the relative importance of transcript- and protein-level regulation (translation and/or turnover) differs among cellular functions and across specific microhabitats or environmental contexts. Furthermore, the degree of concordance between transcript and protein expression can vary across benign versus acutely stressful environmental conditions.
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Affiliation(s)
- Lani U. Gleason
- Department of Biological Sciences, California State University Sacramento, Sacramento, CA 95819, USA
| | - Florian J. Fekete
- Department of Biological Sciences, California State University Sacramento, Sacramento, CA 95819, USA
| | - Richelle L. Tanner
- School of Biological Sciences, Washington State University, Pullman, WA 99163, USA
| | - W. Wesley Dowd
- School of Biological Sciences, Washington State University, Pullman, WA 99163, USA
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Anttila K, Mauduit F, Kanerva M, Götting M, Nikinmaa M, Claireaux G. Cardiovascular oxygen transport and peripheral oxygen extraction capacity contribute to acute heat tolerance in European seabass. Comp Biochem Physiol A Mol Integr Physiol 2023; 275:111340. [PMID: 36347467 DOI: 10.1016/j.cbpa.2022.111340] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 10/23/2022] [Accepted: 11/02/2022] [Indexed: 11/08/2022]
Abstract
This study evaluated whether different parameters describing cardiovascular function, energy metabolism, oxygen transport and oxidative stress were related to the critical thermal maximum (CTMAX) of European seabass (Dicentrarchus labrax) and if there were differential changes in these parameters during and after heat shock in animals with different CTMAX in order to characterize which physiological features make seabass vulnerable to heat waves. Seabass (n = 621) were tested for CTMAX and the physiological parameters were measured in individuals with good or poor temperature tolerance before and after a heat shock (change in temperature from 15 °C to 28 °C in 1.5 h). Fish with good thermal tolerance had larger ventricles with higher maximal heart rate during the heat shock than individuals with poor tolerance. Furthermore, they initially had a high ventricular Ca2+-ATPase activity, which was reduced to a similar level as in fish with poor tolerance following heat shock. The activity of heart lactate dehydrogenase increased in fish with high tolerance, when they were exposed to heat shock, while the aerobic enzyme activity did not differ between groups. The tolerant individuals had smaller red muscle fibers with higher myoglobin content than the poorly tolerant ones. The poorly tolerant individuals had higher hematocrit, which increased with heat shock in both groups. The poorly tolerant individuals had also higher activity of enzymes related to oxidative stress especially after heat shock. In general, CTMAX was not depending on merely one physiological factor but several organ and cellular parameters were related to the CTMAX of seabass and when working in combination they might protect the highly tolerant seabass from future heat waves.
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Affiliation(s)
- Katja Anttila
- Department of Biology, University of Turku, FI-20014 Turku, Finland.
| | - Florian Mauduit
- Université de Bretagne Occidentale, LEMAR (UMR 6539), Unité PFOM-ARN, Centre Ifremer de Bretagne, Plouzané 29280, France
| | - Mirella Kanerva
- Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Miriam Götting
- Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Mikko Nikinmaa
- Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Guy Claireaux
- Université de Bretagne Occidentale, LEMAR (UMR 6539), Unité PFOM-ARN, Centre Ifremer de Bretagne, Plouzané 29280, France
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Wang C, Chen X, Dai Y, Zhang Y, Sun Y, Cui X. Comparative transcriptome analysis of heat-induced domesticated zebrafish during gonadal differentiation. BMC Genom Data 2022; 23:39. [PMID: 35641933 PMCID: PMC9158171 DOI: 10.1186/s12863-022-01058-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 05/24/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The influence of environmental factors, especially temperature, on sex ratio is of great significance to elucidate the mechanism of sex determination. However, the molecular mechanisms by which temperature affects sex determination remains unclear, although a few candidate genes have been found to play a role in the process. In this study, we conducted transcriptome analysis of the effects induced by high temperature on zebrafish during gonad differentiation period. RESULTS Totals of 1171, 1022 and 2921 differentially expressed genes (DEGs) between high temperature and normal temperature were identified at 35, 45 and 60 days post-fertilization (dpf) respectively, revealing that heat shock proteins (HSPs) and DNA methyltransferases (DNMTs) were involved in the heat-exposed sex reversal. The Gene Ontology (GO) terms and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway that were enriched in individuals after heat treatment included Fanconi anemia (FA) pathway, cell cycle, oocyte meiosis and homologous recombination. CONCLUSIONS Our study provides the results of comparative transcriptome analyses between high temperature and normal temperature, and reveals that the molecular mechanism of heat-induced masculinization in zebrafish is strongly related to the expression of HSPs and DNMTs and FA pathway during gonad differentiation.
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Affiliation(s)
- Chenchen Wang
- School of Life and Health Science, Hunan University of Science and Technology, Xiangtan, 411201, Hunan, China
| | - Xuhuai Chen
- School of Life and Health Science, Hunan University of Science and Technology, Xiangtan, 411201, Hunan, China
| | - Yu Dai
- School of Life and Health Science, Hunan University of Science and Technology, Xiangtan, 411201, Hunan, China
| | - Yifei Zhang
- School of Life and Health Science, Hunan University of Science and Technology, Xiangtan, 411201, Hunan, China.,Hunan Key Laboratory of Economic Crops Genetic Improvement and Integrated Utilization, Hunan University of Science and Technology, Xiangtan, 411201, Hunan, China
| | - Yuandong Sun
- School of Life and Health Science, Hunan University of Science and Technology, Xiangtan, 411201, Hunan, China.,Hunan Key Laboratory of Economic Crops Genetic Improvement and Integrated Utilization, Hunan University of Science and Technology, Xiangtan, 411201, Hunan, China
| | - Xiaojuan Cui
- School of Life and Health Science, Hunan University of Science and Technology, Xiangtan, 411201, Hunan, China. .,Hunan Key Laboratory of Economic Crops Genetic Improvement and Integrated Utilization, Hunan University of Science and Technology, Xiangtan, 411201, Hunan, China.
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Sun J, Liu Z, Quan J, Li L, Zhao G, Lu J. RNA-seq Analysis Reveals Alternative Splicing Under Heat Stress in Rainbow Trout (Oncorhynchus mykiss). MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2022; 24:5-17. [PMID: 34787764 DOI: 10.1007/s10126-021-10082-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
Rainbow trout (Oncorhynchus mykiss) is one of the most economically important cold-water farmed species in the world, and transcriptomic studies in response to heat stress have been conducted and will be studied in depth. Alternative splicing (AS), a post-transcriptional regulatory process that regulates gene expression and increases proteomic diversity, is still poorly understood in rainbow trout under heat stress. In the present study, 18,623 alternative splicing events were identified from 9936 genes using RNA transcriptome sequencing technology (RNA-Seq) and genomic information. A total of 2731 differential alternative splicing (DAS) events were found among 2179 differentially expressed genes (DEGs). Gene ontology analysis revealed that the DEGs were mainly enriched in cellular metabolic process, cell part, and organic cyclic compound binding under heat stress. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis displayed that the DEGs were enriched for 39 pathways, and some key pathways, such as lysine degradation, are involved in the regulation of heat stress in liver tissues of rainbow trout. The results were validated by qRT-PCR, confirming reliability of our bioinformatics analysis.
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Affiliation(s)
- Jun Sun
- College of Animal Science & Technology, Gansu Province, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, People's Republic of China
| | - Zhe Liu
- College of Animal Science & Technology, Gansu Province, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, People's Republic of China.
| | - Jinqiang Quan
- College of Animal Science & Technology, Gansu Province, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, People's Republic of China
| | - Lanlan Li
- College of Animal Science & Technology, Gansu Province, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, People's Republic of China
| | - Guiyan Zhao
- College of Animal Science & Technology, Gansu Province, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, People's Republic of China
| | - Junhao Lu
- College of Animal Science & Technology, Gansu Province, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, 730070, People's Republic of China
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Manzon LA, Zak MA, Agee M, Boreham DR, Wilson JY, Somers CM, Manzon RG. Thermal acclimation alters both basal heat shock protein gene expression and the heat shock response in juvenile lake whitefish (Coregonus clupeaformis). J Therm Biol 2022; 104:103185. [DOI: 10.1016/j.jtherbio.2021.103185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/21/2021] [Accepted: 12/31/2021] [Indexed: 12/26/2022]
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Islam MJ, Kunzmann A, Slater MJ. Extreme winter cold-induced osmoregulatory, metabolic, and physiological responses in European seabass (Dicentrarchus labrax) acclimatized at different salinities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 771:145202. [PMID: 33736134 DOI: 10.1016/j.scitotenv.2021.145202] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/09/2021] [Accepted: 01/11/2021] [Indexed: 06/12/2023]
Abstract
Despite climate-change challenges, for most aquaculture species, physiological responses to different salinities during ambient extreme cold events remain unknown. Here, European seabass acclimatized at 3, 6, 12, and 30 PSU were subjected to 20 days of an ambient extreme winter cold event (8 °C), and monitored for growth and physiological performance. Growth performance decreased significantly (p < 0.05) in fish exposed at 3 and 30 PSU compared to 6 and 12 PSU. During cold stress exposure, serum Na+, Cl-, and K+ concentrations were significantly (p < 0.05) increased in fish exposed at 30 PSU. Serum cortisol, glucose, and blood urea nitrogen (BUN) were increased significantly (p < 0.05) in fish exposed at 3 and 30 PSU. In contrast, opposite trends were observed for serum protein, lactate, and triglycerides content during cold exposure. Transaminase activities [glutamic-pyruvate transaminase (GPT), glutamic oxaloacetic transaminase (GOT), lactic acid dehydrogenase (LDH), gamma-glutamyl-transaminase (γGGT)] were significantly higher in fish exposed at 3 and 30 PSU on days 10 and 20. The abundance of heat shock protein 70 (HSP70), tumor necrosis factor-α (TNF-α), cystic fibrosis transmembrane conductance (CFTR) were significantly (p < 0.05) increased in fish exposed at 3 and 30 PSU during cold shock exposure. In contrast, insulin-like growth factor 1 (Igf1) expression was significantly lower in fish exposed at 3 and 30 PSU. Whereas, on day 20, Na+/K+ ATPase α1 and Na+/K+/Cl- cotransporter-1 (NKCC1) were significantly upregulated in fish exposed at 30 PSU, followed by 12, 6, and 3 PSU. Results demonstrated that ambient extreme winter cold events induce metabolic and physiological stress responses and provide a conceivable mechanism by which growth and physiological fitness are limited at cold thermal events. However, during ambient extreme cold (8 °C) exposure, European seabass exhibited better physiological fitness at 12 and 6 PSU water, providing possible insight into future aquaculture management options.
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Affiliation(s)
- Md Jakiul Islam
- Leibniz Centre for Tropical Marine Research (ZMT), 28359 Bremen, Germany; Alfred-Wegener-Institute, Helmholtz-Center for Polar and Marine Research, 27570 Bremerhaven, Germany; Faculty of Biology and Chemistry (FB 02), University of Bremen, 28359 Bremen, Germany.
| | - Andreas Kunzmann
- Leibniz Centre for Tropical Marine Research (ZMT), 28359 Bremen, Germany
| | - Matthew James Slater
- Alfred-Wegener-Institute, Helmholtz-Center for Polar and Marine Research, 27570 Bremerhaven, Germany
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Aslanidi KB, Kharakoz DP. Limits of temperature adaptation and thermopreferendum. Cell Biosci 2021; 11:69. [PMID: 33823918 PMCID: PMC8025563 DOI: 10.1186/s13578-021-00574-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/18/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Managing the limits of temperature adaptation is relevant both in medicine and in biotechnology. There are numerous scattered publications on the identification of the temperature limits of existence for various organisms and using different methods. Dmitry Petrovich Kharakoz gave a general explanation for many of these experimental results. The hypothesis implied that each cycle of synaptic exocytosis includes reversible phase transitions of lipids of the presynaptic membrane due to the entry and subsequent removal of calcium ions from the synaptic terminal. The correspondence of the times of phase transitions has previously been experimentally shown on isolated lipids in vitro. In order to test the hypothesis of D.P. Kharakoz in vivo, we investigated the influence of the temperature of long-term acclimatization on the temperature of heat and cold shock, as well as on the kinetics of temperature adaptation in zebrafish. Testing the hypothesis included a comparison of our experimental results with the results of other authors obtained on various models from invertebrates to humans. RESULTS The viability polygon for Danio rerio was determined by the minimum temperature of cold shock (about 6 °C), maximum temperature of heat shock (about 43 °C), and thermopreferendum temperature (about 27 °C). The ratio of the temperature range of cold shock to the temperature range of heat shock was about 1.3. These parameters obtained for Danio rerio describe with good accuracy those for the planarian Girardia tigrina, the ground squirrel Sermophilus undulatus, and for Homo sapiens. CONCLUSIONS The experimental values of the temperatures of cold shock and heat shock and the temperature of the thermal preferendum correspond to the temperatures of phase transitions of the lipid-protein composition of the synaptic membrane between the liquid and solid states. The viability range for zebrafish coincides with the temperature range, over which enzymes function effectively and also coincides with the viability polygons for the vast majority of organisms. The boundaries of the viability polygon are characteristic biological constants. The viability polygon of a particular organism is determined not only by the genome, but also by the physicochemical properties of lipids that make up the membrane structures of synaptic endings. The limits of temperature adaptation of any biological species are determined by the temperature range of the functioning of its nervous system.
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Affiliation(s)
- K B Aslanidi
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region, Russia, 142290.
| | - D P Kharakoz
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region, Russia, 142290
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9
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Luu I, Ikert H, Craig PM. Chronic exposure to anthropogenic and climate related stressors alters transcriptional responses in the liver of zebrafish (Danio rerio) across multiple generations. Comp Biochem Physiol C Toxicol Pharmacol 2021; 240:108918. [PMID: 33141083 DOI: 10.1016/j.cbpc.2020.108918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/09/2020] [Accepted: 10/18/2020] [Indexed: 01/04/2023]
Abstract
The antidepressant, venlafaxine (VFX), and climate change stressors, such as increased water temperature and decreased dissolved oxygen, are current threats to aquatic environments. This study aimed to determine how microRNAs (miRNAs) and predicted targeted transcripts were altered in livers of zebrafish exposed to these stressors, and livers of their un-exposed F1 and F2 offspring. Following a 21 day exposure to multiple stressors (1 μg/L VFX, +5 °C ambient, 50% O2), then a subsequent 21 day recovery, relative abundances of cyp3a65, hsp70, hsp90, and ppargc1a and miRNAs predicted to target them (miR-142a, miR-16c, miR-181c, and miR-129, respectively) were measured in the liver via quantitative PCR (RT-qPCR). There were significant decreases in miR-142a in the exposed F0 generation and the exposed F1 generation. While there were no changes detected in cyp3a65 relative abundance, there was a significant inverse relationship between cyp3a65 and miR-142a. Hsp70 expression significantly increased in the F1 generation, which persisted to the F2 generation and the relative abundance of hsp90 significantly increased in all generations. There was a significant reduction in miR-181c in the F1 generation, but there was no significant relationship between miR-181c and hsp90. Finally, there was a significant decrease in ppargc1a relative abundance in the F1 generation which was associated with an increase in miR-129. Combined, these results suggest that parental exposure to multiple, environmentally relevant stressors can confer transcriptional and epigenetic responses in the F1 and F2 generations, although identifying which stressor is a driving force becomes unclear.
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Affiliation(s)
- Ivy Luu
- Department of Biology, University of Waterloo, 200 University Ave. W., Waterloo N2L 3G1, Ontario, Canada
| | - Heather Ikert
- Department of Biology, University of Waterloo, 200 University Ave. W., Waterloo N2L 3G1, Ontario, Canada.
| | - Paul M Craig
- Department of Biology, University of Waterloo, 200 University Ave. W., Waterloo N2L 3G1, Ontario, Canada
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Somero GN. The cellular stress response and temperature: Function, regulation, and evolution. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:379-397. [PMID: 31944627 DOI: 10.1002/jez.2344] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/11/2019] [Accepted: 01/02/2020] [Indexed: 01/18/2023]
Abstract
The cellular stress response (CSR) is critical for enabling organisms to cope with thermal damage to proteins, nucleic acids, and membranes. It is a graded response whose properties vary with the degree of cellular damage. Molecular damage has positive, as well as negative, function-perturbing effects. Positive effects include crucial regulatory interactions that orchestrate involvement of the different components of the CSR. Thermally unfolded proteins signal for rapid initiation of transcription of genes encoding heat shock proteins (HSPs), central elements of the heat shock response (HSR). Thermal disruption of messenger RNA (mRNA) secondary structures in untranslated regions leads to the culling of the mRNA pool: thermally labile mRNAs for housekeeping proteins are degraded by exonucleases; heat-resistant mRNAs for stress proteins like HSPs then can monopolize the translational apparatus. Thus, proteins and RNA function as "cellular thermometers," and evolved differences in their thermal stabilities enable rapid initiation of the CSR whenever cell temperature rises significantly above the normal thermal range of a species. Covalent DNA damage, which may result from increased production of reactive oxygen species, is temperature-dependent; its extent may determine cellular survival. High levels of stress that exceed capacities for molecular repair can lead to proteolysis, inhibition of cell division, and programmed cell death (apoptosis). Onset of these processes may occur later in the stress period, after initiation of the HSR, to allow HSPs opportunity to restore protein homeostasis. Delay of these energy costly processes may also result from shortfalls in availability of adenosine triphosphate and reducing power during times of peak stress.
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Affiliation(s)
- George N Somero
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California
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