Mutational analysis of Escherichia coli heat shock transcription factor sigma 32 reveals similarities with sigma 70 in recognition of the -35 promoter element and differences in promoter DNA melting and -10 recognition.

PubMed

Kourennaia, Olga V; Tsujikawa, Laura; Dehaseth, Pieter L

2005-10-01

Upon the exposure of Escherichia coli to high temperature (heat shock), cellular levels of the transcription factor sigma32 rise greatly, resulting in the increased formation of the sigma32 holoenzyme, which is capable of transcription initiation at heat shock promoters. Higher levels of heat shock proteins render the cell better able to cope with the effects of higher temperatures. To conduct structure-function studies on sigma32 in vivo, we have carried out site-directed mutagenesis and employed a previously developed system involving sigma32 expression from one plasmid and a beta-galactosidase reporter gene driven by the sigma32-dependent groE promoter on another in order to monitor the effects of single amino acid substitutions on sigma32 activity. It was found that the recognition of the -35 region involves similar amino acid residues in regions 4.2 of E. coli sigma32 and sigma70. Three conserved amino acids in region 2.3 of sigma32 were found to be only marginally important in determining activity in vivo. Differences between sigma32 and sigma70 in the effects of mutation in region 2.4 on the activities of the two sigma factors are consistent with the pronounced differences between both the amino acid sequences in this region and the recognized promoter DNA sequences.

RNAi screen in Drosophila larvae identifies histone deacetylase 3 as a positive regulator of the hsp70 heat shock gene expression during heat shock.

PubMed

Achary, Bhavana G; Campbell, Katie M; Co, Ivy S; Gilmour, David S

2014-05-01

The transcription regulation of the Drosophila hsp70 gene is a complex process that involves the regulation of multiple steps, including the establishment of paused Pol II and release of Pol II into elongation upon heat shock activation. While the major players involved in the regulation of gene expression have been studied in detail, additional factors involved in this process continue to be discovered. To identify factors involved in hsp70 expression, we developed a screen that capitalizes on a visual assessment of heat shock activation using a hsp70-beta galactosidase reporter and publicly available RNAi fly lines to deplete candidate proteins. We validated the screen by showing that the depletion of HSF, CycT, Cdk9, Nurf 301, or ELL prevented the full induction of hsp70 by heat shock. Our screen also identified the histone deacetylase HDAC3 and its associated protein SMRTER as positive regulators of hsp70 activation. Additionally, we show that HDAC3 and SMRTER contribute to hsp70 gene expression at a step subsequent to HSF-mediated activation and release of the paused Pol II that resides at the promoter prior to heat shock induction. Copyright © 2014 Elsevier B.V. All rights reserved.

Multiple independent regulatory pathways control UBI4 expression after heat shock in Saccharomyces cerevisiae.

PubMed

Simon, J R; Treger, J M; McEntee, K

1999-02-01

Transcription of the polyubiquitin gene UBI4 of Saccharomyces cerevisiae is strongly induced by a variety of environmental stresses, such as heat shock, nutrient depletion and exposure to DNA-damaging agents. This transcriptional response of UBI4 is likely to be the primary mechanism for increasing the pool of ubiquitin for degradation of stress-damaged proteins. Deletion and promoter fusion studies of the 5' regulatory sequences indicated that two different elements, heat shock elements (HSEs) and stress response element (STREs), contributed independently to heat shock regulation of the UBI4 gene. In the absence of HSEs, STRE sequences localized to the intervals -264 to -238 and -215 to -183 were needed for stress control of transcription after heat shock. Site-directed mutagenesis of the STRE (AG4) at -252 to -248 abolished heat shock induction of UBI4 transcription. Northern analysis demonstrated that cells containing either a temperature-sensitive HSF or non-functional Msn2p/Msn4p transcription factors induced high levels of UBI4 transcripts after heat shock. In cells deficient in both heat stress pathways, heat-induced UBI4 transcript levels were considerably lower but not abolished, suggesting a role for another factor(s) in stress control of its expression.

Effect of prior heat shock on heat resistance of Listeria monocytogenes in meat.

PubMed Central

Farber, J M; Brown, B E

1990-01-01

The effect of prior heat shock on the thermal resistance of Listeria monocytogenes in meat was investigated. A sausage mix inoculated with approximately 10(7) L. monocytogenes per g was initially subjected to a heat shock temperature of 48 degrees C before being heated at a final test temperature of 62 or 64 degrees C. Although cells heat shocked at 48 degrees C for 30 or 60 min did not show a significant increase in thermotolerance as compared with control cells (non-heat shocked), bacteria heat shocked for 120 min did, showing an average 2.4-fold increase in the D64 degrees C value. Heat-shocked cells shifted to 4 degrees C appeared to maintain their thermotolerance for at least 24 h after heat shock. PMID:2116757

Systemic Analysis of Heat Shock Response Induced by Heat Shock and a Proteasome Inhibitor MG132

PubMed Central

Kim, Hee-Jung; Joo, Hye Joon; Kim, Yung Hee; Ahn, Soyeon; Chang, Jun; Hwang, Kyu-Baek; Lee, Dong-Hee; Lee, Kong-Joo

2011-01-01

The molecular basis of heat shock response (HSR), a cellular defense mechanism against various stresses, is not well understood. In this, the first comprehensive analysis of gene expression changes in response to heat shock and MG132 (a proteasome inhibitor), both of which are known to induce heat shock proteins (Hsps), we compared the responses of normal mouse fibrosarcoma cell line, RIF- 1, and its thermotolerant variant cell line, TR-RIF-1 (TR), to the two stresses. The cellular responses we examined included Hsp expressions, cell viability, total protein synthesis patterns, and accumulation of poly-ubiquitinated proteins. We also compared the mRNA expression profiles and kinetics, in the two cell lines exposed to the two stresses, using microarray analysis. In contrast to RIF-1 cells, TR cells resist heat shock caused changes in cell viability and whole-cell protein synthesis. The patterns of total cellular protein synthesis and accumulation of poly-ubiquitinated proteins in the two cell lines were distinct, depending on the stress and the cell line. Microarray analysis revealed that the gene expression pattern of TR cells was faster and more transient than that of RIF-1 cells, in response to heat shock, while both RIF-1 and TR cells showed similar kinetics of mRNA expression in response to MG132. We also found that 2,208 genes were up-regulated more than 2 fold and could sort them into three groups: 1) genes regulated by both heat shock and MG132, (e.g. chaperones); 2) those regulated only by heat shock (e.g. DNA binding proteins including histones); and 3) those regulated only by MG132 (e.g. innate immunity and defense related molecules). This study shows that heat shock and MG132 share some aspects of HSR signaling pathway, at the same time, inducing distinct stress response signaling pathways, triggered by distinct abnormal proteins. PMID:21738571

Roles of heat shock factors in gametogenesis and development.

PubMed

Abane, Ryma; Mezger, Valérie

2010-10-01

Heat shock factors form a family of transcription factors (four in mammals), which were named according to the first discovery of their activation by heat shock. As a result of the universality and robustness of their response to heat shock, the stress-dependent activation of heat shock factor became a ‘paradigm’: by binding to conserved DNA sequences (heat shock elements), heat shock factors trigger the expression of genes encoding heat shock proteins that function as molecular chaperones, contributing to establish a cytoprotective state to various proteotoxic stress and in several pathological conditions. Besides their roles in the stress response, heat shock factors perform crucial roles during gametogenesis and development in physiological conditions. First, during these process, in stress conditions, they are either proactive for survival or, conversely, for apoptotic process, allowing elimination or, inversely, protection of certain cell populations in a way that prevents the formation of damaged gametes and secure future reproductive success. Second, heat shock factors display subtle interplay in a tissue- and stage-specific manner, in regulating very specific sets of heat shock genes, but also many other genes encoding growth factors or involved in cytoskeletal dynamics. Third, they act not only by their classical transcription factor activities, but are necessary for the establishment of chromatin structure and, likely, genome stability. Finally, in contrast to the heat shock gene paradigm, heat shock elements bound by heat shock factors in developmental process turn out to be extremely dispersed in the genome, which is susceptible to lead to the future definition of ‘developmental heat shock element’.

Electron heating at interplanetary shocks

NASA Technical Reports Server (NTRS)

Feldman, W. C.; Asbridge, J. R.; Bame, S. J.; Gosling, J. T.; Zwickl, R. D.

1982-01-01

Data for 41 forward interplanetary shocks show that the ratio of downstream to upstream electron temperatures, T/sub e/(d/u) is variable in the range between 1.0 (isothermal) and 3.0. On average, (T/sub e/(d/u) = 1.5 with a standard deviation, sigma e = 0.5. This ratio is less than the average ratio of proton temperatures across the same shocks, (T/sub p/(d/u)) = 3.3 with sigma p = 2.5 as well as the average ratio of electron temperatures across the Earth's bow shock. Individual samples of T/sub e/(d/u) and T/sub p/(d/u) appear to be weakly correlated with the number density ratio. However the amounts of electron and proton heating are well correlated with each other as well as with the bulk velocity difference across each shock. The stronger shocks appear to heat the protons relatively more efficiently than they heat the electrons.

Insect heat shock proteins during stress and diapause.

PubMed

King, Allison M; MacRae, Thomas H

2015-01-07

Insect heat shock proteins include ATP-independent small heat shock proteins and the larger ATP-dependent proteins, Hsp70, Hsp90, and Hsp60. In concert with cochaperones and accessory proteins, heat shock proteins mediate essential activities such as protein folding, localization, and degradation. Heat shock proteins are synthesized constitutively in insects and induced by stressors such as heat, cold, crowding, and anoxia. Synthesis depends on the physiological state of the insect, but the common function of heat shock proteins, often working in networks, is to maintain cell homeostasis through interaction with substrate proteins. Stress-induced expression of heat shock protein genes occurs in a background of protein synthesis inhibition, but in the course of diapause, a state of dormancy and increased stress tolerance, these genes undergo differential regulation without the general disruption of protein production. During diapause, when ATP concentrations are low, heat shock proteins may sequester rather than fold proteins.

Characterization of four heat-shock protein genes from Nile tilapia (Oreochromis niloticus) and demonstration of the inducible transcriptional activity of Hsp70 promoter.

PubMed

Zhang, Lili; Sun, Chengfei; Ye, Xing; Zou, Shuming; Lu, Maixin; Liu, Zhigang; Tian, Yuanyuan

2014-02-01

Heat-shock proteins (Hsps), known as stress proteins and extrinsic chaperones, play important roles in the folding, translocation, and refolding/degradation of proteins. In this study, we identified four Hsps in Nile tilapia (Oreochromis niloticus), which display conserved Hsp characteristics in their predicted amino acid sequences. Further analyses on the structures, homology, and phylogenetics revealed that the four Hsps belong to Hsp70 family. One of them does not contain introns and is named Hsp70, while all the other three contain introns and are named Hsc70-1, Hsc70-2, and Hsc70-3. Expressions of the four Hsp proteins were observed in all examined tissues. Six hours after infection of Streptococcus agalactiae in Nile tilapia, the expression of Hsp70 was significantly increased in the liver, head kidney, spleen and gill, while Hsc70s' expression was unchanged in all examined tissues except the head kidney that showed significantly reduced expression of both Hsc70-2 and Hsc70-3. These results suggest that Hsp70 may participate in the defense against S. agalactiae infection. We then isolated the promoter of Hsp70 gene and inserted it into the donor plasmid of Tgf2 transposon system containing green fluorescent protein (GFP) gene. The plasmid was microinjected into zebrafish embryos, where the expression of GFP was induced by heat shock, S. agalactiae immersion challenge, indicating that the isolated Hsp70 promoter has transcriptional activity and is inducible by both heat shock and bacterial challenge. This promoter may facilitate the future construction of disease-resistant transgenic fish. The work also contributes to the further study of immune response of tilapia after bacterial infection.

Shock heating of the solar wind plasma

NASA Technical Reports Server (NTRS)

Whang, Y. C.; Liu, Shaoliang; Burlaga, L. F.

1990-01-01

The role played by shocks in heating solar-wind plasma is investigated using data on 413 shocks which were identified from the plasma and magnetic-field data collected between 1973 and 1982 by Pioneer and Voyager spacecraft. It is found that the average shock strength increased with the heliocentric distance outside 1 AU, reaching a maximum near 5 AU, after which the shock strength decreased with the distance; the entropy of the solar wind protons also reached a maximum at 5 AU. An MHD simulation model in which shock heating is the only heating mechanism available was used to calculate the entropy changes for the November 1977 event. The calculated entropy agreed well with the value calculated from observational data, suggesting that shocks are chiefly responsible for heating solar wind plasma between 1 and 15 AU.

Lipoic Acid Exerts Antioxidant and Anti-inflammatory Effects in Response to Heat Shock in C2C12 Myotubes.

PubMed

Lee, Cheng-Tse; Chang, Li-Ching; Wu, Pei-Fung

2016-06-01

This study explored that lipoic acid treatment for 24 h significantly upregulated and promoted heat shock-induced catalase expression and downregulated GPx1 messenger RNA (mRNA) expression, indicating that lipoic acid exhibits antioxidant activity in the decomposition of hydrogen peroxide by upregulating catalase expression. Moreover, lipoic acid treatment for 3 h increased and promoted heat shock-induced interleukin (IL)-6 mRNA and protein levels and that for 24 h downregulated IL-6 mRNA expression, suggesting a dual effect of lipoic acid on IL-6 regulation. Lipoic acid alone failed to increase or reduce tumor necrosis factor (TNF)-α mRNA and protein levels, whereas heat shock alone downregulated TNF-α mRNA and protein expression. These data suggest that lipoic acid does not have a proinflammatory role and that heat shock acts as an anti-inflammatory agent by downregulating TNF-α expression in C2C12 myotubes. Moreover, lipoic acid or heat shock alone upregulated the IL-6 receptor (IL-6R-α) and glycoprotein 130 (gp130) mRNA expression followed by IL-6 expression; these data indicate that the regulation of lipoic acid or heat shock is mediated by IL-6R signaling, thus suggesting that C2C12 myotubes possesses a mechanism for regulating IL-6R and gp130 expression following lipoic acid treatment or heat shock.

Whole-Genome Analysis Reveals That Active Heat Shock Factor Binding Sites Are Mostly Associated with Non-Heat Shock Genes in Drosophila melanogaster

PubMed Central

Gonsalves, Sarah E.; Moses, Alan M.; Razak, Zak; Robert, Francois; Westwood, J. Timothy

2011-01-01

During heat shock (HS) and other stresses, HS gene transcription in eukaryotes is up-regulated by the transcription factor heat shock factor (HSF). While the identities of the major HS genes have been known for more than 30 years, it has been suspected that HSF binds to numerous other genes and potentially regulates their transcription. In this study, we have used a chromatin immunoprecipitation and microarray (ChIP-chip) approach to identify 434 regions in the Drosophila genome that are bound by HSF. We have also performed a transcript analysis of heat shocked Kc167 cells and third instar larvae and compared them to HSF binding sites. The heat-induced transcription profiles were quite different between cells and larvae and surprisingly only about 10% of the genes associated with HSF binding sites show changed transcription. There were also genes that showed changes in transcript levels that did not appear to correlate with HSF binding sites. Analysis of the locations of the HSF binding sites revealed that 57% were contained within genes with approximately 2/3rds of these sites being in introns. We also found that the insulator protein, BEAF, has enriched binding prior to HS to promoters of genes that are bound by HSF upon HS but that are not transcriptionally induced during HS. When the genes associated with HSF binding sites in promoters were analyzed for gene ontology terms, categories such as stress response and transferase activity were enriched whereas analysis of genes having HSF binding sites in introns identified those categories plus ones related to developmental processes and reproduction. These results suggest that Drosophila HSF may be regulating many genes besides the known HS genes and that some of these genes may be regulated during non-stress conditions. PMID:21264254

Whole-genome analysis reveals that active heat shock factor binding sites are mostly associated with non-heat shock genes in Drosophila melanogaster.

PubMed

Gonsalves, Sarah E; Moses, Alan M; Razak, Zak; Robert, Francois; Westwood, J Timothy

2011-01-14

During heat shock (HS) and other stresses, HS gene transcription in eukaryotes is up-regulated by the transcription factor heat shock factor (HSF). While the identities of the major HS genes have been known for more than 30 years, it has been suspected that HSF binds to numerous other genes and potentially regulates their transcription. In this study, we have used a chromatin immunoprecipitation and microarray (ChIP-chip) approach to identify 434 regions in the Drosophila genome that are bound by HSF. We have also performed a transcript analysis of heat shocked Kc167 cells and third instar larvae and compared them to HSF binding sites. The heat-induced transcription profiles were quite different between cells and larvae and surprisingly only about 10% of the genes associated with HSF binding sites show changed transcription. There were also genes that showed changes in transcript levels that did not appear to correlate with HSF binding sites. Analysis of the locations of the HSF binding sites revealed that 57% were contained within genes with approximately 2/3rds of these sites being in introns. We also found that the insulator protein, BEAF, has enriched binding prior to HS to promoters of genes that are bound by HSF upon HS but that are not transcriptionally induced during HS. When the genes associated with HSF binding sites in promoters were analyzed for gene ontology terms, categories such as stress response and transferase activity were enriched whereas analysis of genes having HSF binding sites in introns identified those categories plus ones related to developmental processes and reproduction. These results suggest that Drosophila HSF may be regulating many genes besides the known HS genes and that some of these genes may be regulated during non-stress conditions.

Integrative analysis of the heat shock response in Aspergillus fumigatus

PubMed Central

2010-01-01

Background Aspergillus fumigatus is a thermotolerant human-pathogenic mold and the most common cause of invasive aspergillosis (IA) in immunocompromised patients. Its predominance is based on several factors most of which are still unknown. The thermotolerance of A. fumigatus is one of the traits which have been assigned to pathogenicity. It allows the fungus to grow at temperatures up to and above that of a fevered human host. To elucidate the mechanisms of heat resistance, we analyzed the change of the A. fumigatus proteome during a temperature shift from 30°C to 48°C by 2D-fluorescence difference gel electrophoresis (DIGE). To improve 2D gel image analysis results, protein spot quantitation was optimized by missing value imputation and normalization. Differentially regulated proteins were compared to previously published transcriptome data of A. fumigatus. The study was augmented by bioinformatical analysis of transcription factor binding sites (TFBSs) in the promoter region of genes whose corresponding proteins were differentially regulated upon heat shock. Results 91 differentially regulated protein spots, representing 64 different proteins, were identified by mass spectrometry (MS). They showed a continuous up-, down- or an oscillating regulation. Many of the identified proteins were involved in protein folding (chaperones), oxidative stress response, signal transduction, transcription, translation, carbohydrate and nitrogen metabolism. A correlation between alteration of transcript levels and corresponding proteins was detected for half of the differentially regulated proteins. Interestingly, some previously undescribed putative targets for the heat shock regulator Hsf1 were identified. This provides evidence for Hsf1-dependent regulation of mannitol biosynthesis, translation, cytoskeletal dynamics and cell division in A. fumigatus. Furthermore, computational analysis of promoters revealed putative binding sites for an AP-2alpha-like transcription factor

Heat shock treatment improves Trametes versicolor laccase production.

PubMed

Wang, Feng; Guo, Chen; Wei, Tao; Zhang, Tian; Liu, Chun-Zhao

2012-09-01

An efficient heat shock strategy has been developed to improve laccase production in submerged Trametes versicolor cultures. The optimized heat shock strategy consists of subjecting T. versicolor mycelial pellets to three heat shock treatments at 45 °C for 45 min, starting at culture day 0, with a 24-h interval between treatments. Laccase production increased by more than 1.6-fold relative to the control in both flasks and a 5-L bioreactor because the expression of the laccase gene was enhanced by heat shock induction. The present work demonstrates that heat shock induction is a promising method because it both improves fungal laccase production and has a good potential in industrial application.

A gene-specific non-enhancer sequence is critical for expression from the promoter of the small heat shock protein gene αB-crystallin

PubMed Central

2014-01-01

Background Deciphering of the information content of eukaryotic promoters has remained confined to universal landmarks and conserved sequence elements such as enhancers and transcription factor binding motifs, which are considered sufficient for gene activation and regulation. Gene-specific sequences, interspersed between the canonical transacting factor binding sites or adjoining them within a promoter, are generally taken to be devoid of any regulatory information and have therefore been largely ignored. An unanswered question therefore is, do gene-specific sequences within a eukaryotic promoter have a role in gene activation? Here, we present an exhaustive experimental analysis of a gene-specific sequence adjoining the heat shock element (HSE) in the proximal promoter of the small heat shock protein gene, αB-crystallin (cryab). These sequences are highly conserved between the rodents and the humans. Results Using human retinal pigment epithelial cells in culture as the host, we have identified a 10-bp gene-specific promoter sequence (GPS), which, unlike an enhancer, controls expression from the promoter of this gene, only when in appropriate position and orientation. Notably, the data suggests that GPS in comparison with the HSE works in a context-independent fashion. Additionally, when moved upstream, about a nucleosome length of DNA (−154 bp) from the transcription start site (TSS), the activity of the promoter is markedly inhibited, suggesting its involvement in local promoter access. Importantly, we demonstrate that deletion of the GPS results in complete loss of cryab promoter activity in transgenic mice. Conclusions These data suggest that gene-specific sequences such as the GPS, identified here, may have critical roles in regulating gene-specific activity from eukaryotic promoters. PMID:24589182

Arctigenin from Fructus Arctii is a novel suppressor of heat shock response in mammalian cells

PubMed Central

Ishihara, Keiichi; Yamagishi, Nobuyuki; Saito, Youhei; Takasaki, Midori; Konoshima, Takao; Hatayama, Takumi

2006-01-01

Because heat shock proteins (Hsps) are involved in protecting cells and in the pathophysiology of diseases such as inflammation, cancer, and neurodegenerative disorders, the use of regulators of the expression of Hsps in mammalian cells seems to be useful as a potential therapeutic modality. To identify compounds that modulate the response to heat shock, we analyzed several natural products using a mammalian cell line containing an hsp promoter-regulated reporter gene. In this study, we found that an extract from Fructus Arctii markedly suppressed the expression of Hsp induced by heat shock. A component of the extract arctigenin, but not the component arctiin, suppressed the response at the level of the activation of heat shock transcription factor, the induction of mRNA, and the synthesis and accumulation of Hsp. Furthermore, arctigenin inhibited the acquisition of thermotolerance in mammalian cells, including cancer cells. Thus, arctigenin seemed to be a new suppressive regulator of heat shock response in mammalian cells, and may be useful for hyperthermia cancer therapy. PMID:16817321

Ultrafast collisional ion heating by electrostatic shocks.

PubMed

Turrell, A E; Sherlock, M; Rose, S J

2015-11-13

High-intensity lasers can be used to generate shockwaves, which have found applications in nuclear fusion, proton imaging, cancer therapies and materials science. Collisionless electrostatic shocks are one type of shockwave widely studied for applications involving ion acceleration. Here we show a novel mechanism for collisionless electrostatic shocks to heat small amounts of solid density matter to temperatures of ∼keV in tens of femtoseconds. Unusually, electrons play no direct role in the heating and it is the ions that determine the heating rate. Ions are heated due to an interplay between the electric field of the shock, the local density increase during the passage of the shock and collisions between different species of ion. In simulations, these factors combine to produce rapid, localized heating of the lighter ion species. Although the heated volume is modest, this would be one of the fastest heating mechanisms discovered if demonstrated in the laboratory.

The interactive association between heat shock factor 1 and heat shock proteins in primary myocardial cells subjected to heat stress.

PubMed

Tang, Shu; Chen, Hongbo; Cheng, Yanfen; Nasir, Mohammad Abdel; Kemper, Nicole; Bao, Endong

2016-01-01

Heat shock factor 1 (HSF1) is a heat shock transcription factor that rapidly induces heat shock gene transcription following thermal stress. In this study, we subjected primary neonatal rat myocardial cells to heat stress in vitro to create a model system for investigating the trends in expression and association between various heat shock proteins (HSPs) and HSF1 under adverse environmental conditions. After the cells were subjected to heat stress at 42˚C for different periods of time, HSP and HSF1 mRNA and protein levels were detected by qPCR and western blot analysis in the heat-stressed cells. The HSF1 expression levels significantly increased in the cells following 120 min of exposure to heat stess compared to the levels observed at the beginning of heat stress exposure. HSP90 followed a similar trend in expression to HSF1, whereas HSP70 followed an opposite trend. However, no significant changes were observed in the crystallin, alpha B (CRYAB, also known as HSP beta-5) expression levels during the 480‑min period of exposure to heat stress. The interaction between the HSPs and HSF1 was analyzed by STRING 9.1, and it was found that HSF1 interacted with HSP90 and HSP70, and that it did not play a role in regulating CRYAB expression. Based on our findings, HSP70 may suppress HSF1 in rat myocardial cells under conditions of heat stress. Furthermore, our data demonstrate that HSF1 is not the key factor for all HSPs, and this was particularly the case for CRYAB.

The interactive association between heat shock factor 1 and heat shock proteins in primary myocardial cells subjected to heat stress

PubMed Central

TANG, SHU; CHEN, HONGBO; CHENG, YANFEN; NASIR, MOHAMMAD ABDEL; KEMPER, NICOLE; BAO, ENDONG

2016-01-01

Heat shock factor 1 (HSF1) is a heat shock transcription factor that rapidly induces heat shock gene transcription following thermal stress. In this study, we subjected primary neonatal rat myocardial cells to heat stress in vitro to create a model system for investigating the trends in expression and association between various heat shock proteins (HSPs) and HSF1 under adverse environmental conditions. After the cells were subjected to heat stress at 42°C for different periods of time, HSP and HSF1 mRNA and protein levels were detected by qPCR and western blot analysis in the heat-stressed cells. The HSF1 expression levels significantly increased in the cells following 120 min of exposure to heat stess compared to the levels observed at the beginning of heat stress exposure. HSP90 followed a similar trend in expression to HSF1, whereas HSP70 followed an opposite trend. However, no significant changes were observed in the crystallin, alpha B (CRYAB, also known as HSP beta-5) expression levels during the 480-min period of exposure to heat stress. The interaction between the HSPs and HSF1 was analyzed by STRING 9.1, and it was found that HSF1 interacted with HSP90 and HSP70, and that it did not play a role in regulating CRYAB expression. Based on our findings, HSP70 may suppress HSF1 in rat myocardial cells under conditions of heat stress. Furthermore, our data demonstrate that HSF1 is not the key factor for all HSPs, and this was particularly the case for CRYAB. PMID:26719858

Exciting cell membranes with a blustering heat shock.

PubMed

Liu, Qiang; Frerck, Micah J; Holman, Holly A; Jorgensen, Erik M; Rabbitt, Richard D

2014-04-15

Brief heat shocks delivered to cells by pulsed laser light can evoke action potentials in neurons and contraction in cardiomyocytes, but the primary biophysical mechanism has been elusive. In this report we show in the neuromuscular junction of Caenorhabditis elegans that application of a 500°C/s heat shock for 500 μs evoked ~35 pA of excitatory current and injected ~23 fC(femtocoulomb) of charge into the cell while raising the temperature only 0.25°C. The key variable driving the current was the rate of change of temperature (dT/dt heat shock), not temperature itself. The photothermal heat shock current was voltage-dependent and was from thermally driven displacement of ions near the plasma membrane. The charge movement was rapid during the heat shock and slow during thermal relaxation, thus leading to an asymmetrical capacitive current that briefly depolarized the cell. A simple quantitative model is introduced to describe modulation of the membrane potential and facilitate practical application of optical heat shock stimuli. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Heat shock protein expression enhances heat tolerance of reptile embryos

PubMed Central

Gao, Jing; Zhang, Wen; Dang, Wei; Mou, Yi; Gao, Yuan; Sun, Bao-Jun; Du, Wei-Guo

2014-01-01

The role of heat shock proteins (HSPs) in heat tolerance has been demonstrated in cultured cells and animal tissues, but rarely in whole organisms because of methodological difficulties associated with gene manipulation. By comparing HSP70 expression patterns among representative species of reptiles and birds, and by determining the effect of HSP70 overexpression on embryonic development and hatchling traits, we have identified the role of HSP70 in the heat tolerance of amniote embryos. Consistent with their thermal environment, and high incubation temperatures and heat tolerance, the embryos of birds have higher onset and maximum temperatures for induced HSP70 than do reptiles, and turtles have higher onset and maximum temperatures than do lizards. Interestingly, the trade-off between benefits and costs of HSP70 overexpression occurred between life-history stages: when turtle embryos developed at extreme high temperatures, HSP70 overexpression generated benefits by enhancing embryo heat tolerance and hatching success, but subsequently imposed costs by decreasing heat tolerance of surviving hatchlings. Taken together, the correlative and causal links between HSP70 and heat tolerance provide, to our knowledge, the first unequivocal evidence that HSP70 promotes thermal tolerance of embryos in oviparous amniotes. PMID:25080340

Function and regulation of heat shock factor 2 during mouse embryogenesis

PubMed Central

Rallu, M.; Loones, Mt.; Lallemand, Y.; Morimoto, R.; Morange, M.; Mezger, V.

1997-01-01

The spontaneous expression of heat shock genes during development is well documented in many animal species, but the mechanisms responsible for this developmental regulation are only poorly understood. In vertebrates, additional heat shock transcription factors, distinct from the heat shock factor 1 (HSF1) involved in the stress response, were suggested to be involved in this developmental control. In particular, the mouse HSF2 has been found to be active in testis and during preimplantation development. However, the role of HSF2 and its mechanism of activation have remained elusive due to the paucity of data on its expression during development. In this study, we have examined HSF2 expression during the postimplantation phase of mouse development. Our data show a developmental regulation of HSF2, which is expressed at least until 15.5 days of embryogenesis. It becomes restricted to the central nervous system during the second half of gestation. It is expressed in the ventricular layer of the neural tube which contains mitotically active cells but not in postmitotic neurons. Parallel results were obtained for mRNA, protein, and activity levels, demonstrating that the main level of control was transcriptional. The detailed analysis of the activity of a luciferase reporter gene under the control of the hsp70.1 promoter, as well as the description of the protein expression patterns of the major heat shock proteins in the central nervous system, show that HSF2 and heat shock protein expression domains do not coincide. This result suggests that HFS2 might be involved in other regulatory developmental pathways and paves the way to new functional approaches. PMID:9122205

Modification of the hTERT promoter by heat shock elements enhances the efficiency and specificity of cancer targeted gene therapy.

PubMed

Wang, Xiaolong; Zhou, PeiHua; Sun, XueJun; Wei, GuangBing; Zhang, Li; Wang, Hui; Yao, JianFeng; Jia, PengBo; Zheng, JianBao

2016-05-01

One of the current challenges facing cancer gene therapy is the tumour-specific targeting of therapeutic genes. Effective targeting in gene therapy requires accurate spatial and temporal control of gene expression. To develop a sufficient and accurate tumour-targeting method for cancer gene therapy, we have investigated the use of hyperthermia to control the expression of a transgene under the control of the human telomerase reverse transcriptase (hTERT) promoter and eight heat shock elements (8HSEs). Luciferase reporters were constructed by inserting eight HSEs and the hTERT promoter (8HSEs-hTERTp) upstream of the pGL4.20 vector luciferase gene. The luciferase activity of the hTERT promoter and 8HSEs-hTERT promoter were then compared in the presence and absence of heat. The differences in luciferase activity were analysed using dual luciferase assays in SW480 (high hTERT expression), MKN28 and MRC-5 cells (low hTERT expression). The luciferase activity of the Hsp70B promoter was also compared to the 8HSEs-hTERT promoter in the above listed cell lines. Lentiviral vector and heat-induced expression of EGFP expression under the control of the 8HSEs-hTERT promoter in cultured cells and mouse tumour xenografts was measured by reverse transcription polymerase (RT-PCR), Western blot and immunofluorescence assays. hTERT promoter activity was higher in SW480 cells than in MKN28 or MRC-5 cells. At 43 °C, the luciferase activity of the 8HSEs-hTERT promoter was significantly increased in SW480 cells, but not in MKN28 or MRC-5 cells. Importantly, the differences in luciferase activity were much more obvious in both high (SW480) and low (MKN28 and MRC-5) hTERT expressing cells when the activity of the 8HSEs-hTERT promoter was compared to the Hsp70B promoter. Moreover, under the control of 8HSEs-hTERT promoter in vitro and in vivo, EGFP expression was obviously increased by heat treatment in SW480 cells but not in MKN28 or MRC-5 cells, nor was expression increased under

Heat shock modulates the subcellular localization, stability, and activity of HIPK2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Upadhyay, Mamta; Bhadauriya, Pratibha; Ganesh, Subramaniam, E-mail: sganesh@iitk.ac.in

2016-04-15

The homeodomain-interacting protein kinase-2 (HIPK2) is a highly conserved serine/threonine kinase and is involved in transcriptional regulation. HIPK2 is a highly unstable protein, and is kept at a low level under normal physiological conditions. However, exposure of cells to physiological stress – such as hypoxia, oxidative stress, or UV damage – is known to stabilize HIPK2, leading to the HIPK2-dependent activation of p53 and the cell death pathway. Therefore HIPK2 is also known as a stress kinase and as a stress-activated pro-apoptotic factor. We demonstrate here that exposure of cells to heat shock results in the stabilization of HIPK2 andmore » the stabilization is mediated via K63-linked ubiquitination. Intriguingly, a sub-lethal heat shock (42 °C, 1 h) results in the cytoplasmic localization of HIPK2, while a lethal heat shock (45 °C, 1 h) results in its nuclear localization. Cells exposed to the lethal heat shock showed significantly higher levels of the p53 activity than those exposed to the sub-lethal thermal stress, suggesting that both the level and the nuclear localization are essential for the pro-apoptotic activity of HIPK2 and that the lethal heat shock could retain the HIPK2 in the nucleus to promote the cell death. Taken together our study underscores the importance of HIPK2 in stress mediated cell death, and that the HIPK2 is a generic stress kinase that gets activated by diverse set of physiological stressors.« less

Analysis of Msx1 and Msx2 transactivation function in the context of the heat shock 70 (Hspa1b) gene promoter.

PubMed

Zhuang, Fengfeng; Nguyen, Manuel P; Shuler, Charles; Liu, Yi-Hsin

2009-04-03

Previous studies have shown that Msx proteins control gene transcription predominantly through repression mechanisms. However, gene expression studies using either the gain-of-function or the loss-of-function mutants revealed many gene targets whose expression require functional Msx proteins. To date, investigations into the mechanisms of Msx-dependent transactivation have been hindered by the lack of a responsive promoter. Here, we demonstrated the usefulness of the mouse Hspa1b promoter in probing Msx-dependent mechanisms of gene activation. We showed that Msx protein activates Hspa1b promoter via its C-terminal domain. The activation absolutely depends on the HSEs and physical interactions between Msx proteins and heat shock factors may play a contributing role.

Heat shock protein expression enhances heat tolerance of reptile embryos.

PubMed

Gao, Jing; Zhang, Wen; Dang, Wei; Mou, Yi; Gao, Yuan; Sun, Bao-Jun; Du, Wei-Guo

2014-09-22

The role of heat shock proteins (HSPs) in heat tolerance has been demonstrated in cultured cells and animal tissues, but rarely in whole organisms because of methodological difficulties associated with gene manipulation. By comparing HSP70 expression patterns among representative species of reptiles and birds, and by determining the effect of HSP70 overexpression on embryonic development and hatchling traits, we have identified the role of HSP70 in the heat tolerance of amniote embryos. Consistent with their thermal environment, and high incubation temperatures and heat tolerance, the embryos of birds have higher onset and maximum temperatures for induced HSP70 than do reptiles, and turtles have higher onset and maximum temperatures than do lizards. Interestingly, the trade-off between benefits and costs of HSP70 overexpression occurred between life-history stages: when turtle embryos developed at extreme high temperatures, HSP70 overexpression generated benefits by enhancing embryo heat tolerance and hatching success, but subsequently imposed costs by decreasing heat tolerance of surviving hatchlings. Taken together, the correlative and causal links between HSP70 and heat tolerance provide, to our knowledge, the first unequivocal evidence that HSP70 promotes thermal tolerance of embryos in oviparous amniotes. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

dFOXO Activates Large and Small Heat Shock Protein Genes in Response to Oxidative Stress to Maintain Proteostasis in Drosophila.

PubMed

Donovan, Marissa R; Marr, Michael T

2016-09-02

Maintaining protein homeostasis is critical for survival at the cellular and organismal level (Morimoto, R. I. (2011) Cold Spring Harb. Symp. Quant. Biol. 76, 91-99). Cells express a family of molecular chaperones, the heat shock proteins, during times of oxidative stress to protect against proteotoxicity. We have identified a second stress responsive transcription factor, dFOXO, that works alongside the heat shock transcription factor to activate transcription of both the small heat shock protein and the large heat shock protein genes. This expression likely protects cells from protein misfolding associated with oxidative stress. Here we identify the regions of the Hsp70 promoter essential for FOXO-dependent transcription using in vitro methods and find a physiological role for FOXO-dependent expression of heat shock proteins in vivo. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Heat Shock Proteins Promote Cancer: It's a Protection Racket.

PubMed

Calderwood, Stuart K; Gong, Jianlin

2016-04-01

Heat shock proteins (HSP) are expressed at high levels in cancer and form a fostering environment that is essential for tumor development. Here, we review the recent data in this area, concentrating mainly on Hsp27, Hsp70, and Hsp90. The overriding role of HSPs in cancer is to stabilize the active functions of overexpressed and mutated cancer genes. Thus, elevated HSPs are required for many of the traits that underlie the morbidity of cancer, including increased growth, survival, and formation of secondary cancers. In addition, HSPs participate in the evolution of cancer treatment resistance. HSPs are also released from cancer cells and influence malignant properties by receptor-mediated signaling. Current data strongly support efforts to target HSPs in cancer treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modification of embryonic resistance to heat shock in cattle by melatonin and genetic variation in HSPA1L.

PubMed

Ortega, M Sofia; Rocha-Frigoni, Nathália A S; Mingoti, Gisele Zoccal; Roth, Zvi; Hansen, Peter J

2016-11-01

The objectives were to test whether (1) melatonin blocks inhibition of embryonic development caused by heat shock at the zygote stage, and (2) the frequency of a thermoprotective allele for HSPA1L is increased in blastocysts formed from heat-shocked zygotes as compared with blastocysts from control zygotes. It was hypothesized that melatonin prevents effects of heat shock on development by reducing accumulation of reactive oxygen species (ROS) and that embryos inheriting the thermoprotective allele of HSPA1L would be more likely to survive heat shock. Effects of 1 µM melatonin on ROS were determined in experiments 1 and 2. Zygotes were cultured at 38.5 or 40°C for 3 h in the presence of CellROX reagent (ThermoFisher Scientific, Waltham, MA). Culture was in a low [5% (vol/vol)] oxygen (experiment 1) or low or high [21% (vol/vol)] oxygen environment (experiment 2). Heat shock and high oxygen increased ROS; melatonin decreased ROS. Development was assessed in experiments 3 and 4. In experiment 3, zygotes were cultured in low oxygen ± 1 µM melatonin and exposed to 38.5 or 40°C for 12 h (experiment 1) beginning 8 h after fertilization. Melatonin did not protect the embryo from heat shock. Experiment 4 was performed similarly except that temperature treatments (38.5 or 40°C, 24 h) were performed in a low or high oxygen environment (2×2 × 2 factorial design with temperature, melatonin, and oxygen concentration as main effects), and blastocysts were genotyped for a deletion (D) mutation (C→D) in the promoter region of HSPA1L associated with thermotolerance. Heat shock decreased percent of zygotes developing to the blastocyst stage independent of melatonin or oxygen concentration. Frequency of genotypes for HSPA1L was affected by oxygen concentration and temperature, with an increase in the D allele for blastocysts that developed in high oxygen and following heat shock. It was concluded that (1) lack of effect of melatonin or oxygen concentration on embryonic

Expression of hsrω-RNAi transgene prior to heat shock specifically compromises accumulation of heat shock-induced Hsp70 in Drosophila melanogaster.

PubMed

Singh, Anand K; Lakhotia, Subhash C

2016-01-01

A delayed organismic lethality was reported in Drosophila following heat shock when developmentally active and stress-inducible noncoding hsrω-n transcripts were down-regulated during heat shock through hs-GAL4-driven expression of the hsrω-RNAi transgene, despite the characteristic elevation of all heat shock proteins (Hsp), including Hsp70. Here, we show that hsrω-RNAi transgene expression prior to heat shock singularly prevents accumulation of Hsp70 in all larval tissues without affecting transcriptional induction of hsp70 genes and stability of their transcripts. Absence of the stress-induced Hsp70 accumulation was not due to higher levels of Hsc70 in hsrω-RNAi transgene-expressing tissues. Inhibition of proteasomal activity during heat shock restored high levels of the induced Hsp70, suggesting very rapid degradation of the Hsp70 even during the stress when hsrω-RNAi transgene was expressed ahead of heat shock. Unexpectedly, while complete absence of hsrω transcripts in hsrω (66) homozygotes (hsrω-null) did not prevent high accumulation of heat shock-induced Hsp70, hsrω-RNAi transgene expression in hsrω-null background blocked Hsp70 accumulation. Nonspecific RNAi transgene expression did not affect Hsp70 induction. These observations reveal that, under certain conditions, the stress-induced Hsp70 can be selectively and rapidly targeted for proteasomal degradation even during heat shock. In the present case, the selective degradation of Hsp70 does not appear to be due to down-regulation of the hsrω-n transcripts per se; rather, this may be an indirect effect of the expression of hsrω-RNAi transgene whose RNA products may titrate away some RNA-binding proteins which may also be essential for stability of the induced Hsp70.

Anyalysis of Msx1 and Msx2 Transactivation Function in the Context of the Heat Shock 70 (Hspa1b) Gene Promoter

PubMed Central

Zhuang, Fengfeng; Nguyen, Manuel P.; Shuler, Charles; Liu, Yi-Hsin

2009-01-01

Previous studies have shown that Msx proteins control gene transcription predominantly through repression mechanisms. However, gene expression studies using either the gain-of-function or the loss-of-function mutants revealed many gene targets whose expression require functional Msx proteins. To date, investigations into the mechanisms of Msx-dependent trans-activation have been hindered by the lack of a responsive promoter. Here, we demonstrated the usefulness of the mouse Hspa1b promoter in probing Msx-dependent mechanisms of gene activation. We showed that Msx protein activates Hspa1b promoter via its C-terminal domain. The activation absolutely depends on the HSEs and physical interactions between Msx proteins and Heat shock factors may play a contributing role. PMID:19338779

Heat shock proteins and heat shock factor 1 in carcinogenesis and tumor development: an update

PubMed Central

2013-01-01

Heat shock proteins (HSP) are a subset of the molecular chaperones, best known for their rapid and abundant induction by stress. HSP genes are activated at the transcriptional level by heat shock transcription factor 1 (HSF1). During the progression of many types of cancer, this heat shock transcriptional regulon becomes co-opted by mechanisms that are currently unclear, although evidently triggered in the emerging tumor cell. Concerted activation of HSF1 and the accumulation of HSPs then participates in many of the traits that permit the malignant phenotype. Thus cancers of many histologies exhibit activated HSF1 and increased HSP levels that may help to deter tumor suppression and evade therapy in the clinic. We review here the extensive work that has been carried out and is still in progress aimed at: (1) understanding the oncogenic mechanisms by which HSP genes are switched on, (2) determining the roles of HSF1 / HSP in malignant transformation and, (3) discovering approaches to therapy based on disrupting the influence of the HSF1 controlled transcriptome in cancer. PMID:22885793

Mathematical Modeling of the Heat-Shock Response in HeLa Cells

DTIC Science & Technology

2015-07-01

Petre et al. (16), but with some critical changes, which are detailed below. 2HSF4HSF2; (1) HSFþ HSF24HSF3; (2) HSF3 þ HSE4HSF3 : HSE ; (3) HSF3 : HSE ... HSE /HSP : HSFþ HSEþ 2HSF; (10) HSP/; (11) Prot/MFP; (12) HSPþMFP4HSP : MFP; (13) HSP : MFP/HSPþ Prot: (14) The heat-shock response is initiated by a... HSE , heat-shock element; HSF, heat-shock factor; HSP, heat-shock protein; MFP, misfolded protein; mRNA, heat-shock protein messenger RNA; and Prot

Transfection of cultured cells of the cotton boll weevil, Anthonomus grandis, with a heat-shock-promoter-chloramphenicol-acetyltransferase construct.

PubMed

Stiles, B; Heilmann, J; Sparks, R B; Santoso, A; Leopold, R A

1992-01-01

Expression of heat shock proteins (hsp) in the BRL-AG-3C cell line from the cotton boll weevil was examined. It was determined that the maximal expression of endogenous hsp occurred at 41 degrees C. Various transfection methods were then compared using this cell line in conjunction with a transiently expressed bacterial gene marker (chloramphenicol acetyltransferase) which was under the control of the Drosophila hsp 70 gene promoter. The cationic lipid preparation Lipofectin was found to be very efficient at transfecting the boll weevil cells. Polylysine and 20-hydroxyecdysone-conjugated polylysine were moderately effective, whereas polybrene and electroporation, under the conditions reported herein, were ineffective at transfecting this cell line.

The heat shock protein 60 promotes progesterone synthesis in mitochondria of JEG-3 cells.

PubMed

Monreal-Flores, Jessica; Espinosa-García, María Teresa; García-Regalado, Alejandro; Arechavaleta-Velasco, Fabian; Martínez, Federico

2017-06-01

Progesterone synthesis in human placenta is essential to maintain pregnancy. The limiting step in placental progesterone synthesis is cholesterol transport from the cytoplasm to the inner mitochondrial membrane. Multiple proteins located in mitochondrial contact sites seem to play a key role in this process. Previously, our group identified the heat shock protein 60 (HSP60) as part of mitochondrial contact sites in human placenta, suggesting its participation in progesterone synthesis. Here, we examined the role of HSP60 in progesterone synthesis. Our results show that over-expression of HSP60 in human placental choriocarcinoma cells (JEG-3) and human embryonic kidney 293 cells (HEK293) promotes progesterone synthesis. Furthermore, incubation of the HSP60 recombinant protein with intact isolated mitochondria from JEG-3 cells also promotes progesterone synthesis in a dose-related fashion. We also show that HSP60 interacts with STARD3 and P450scc proteins from mitochondrial membrane contact sites. Finally, we show that the HSP60 recombinant protein binds cholesterol. Ours results demonstrate that HSP60 participates in mitochondrial progesterone synthesis. These findings provide novel insights into progesterone synthesis in the human placenta and its role in maintaining pregnancy. Copyright © 2017 Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

BH3-Only Protein BIM Mediates Heat Shock-Induced Apoptosis

PubMed Central

Mahajan, Indra M.; Chen, Miao-Der; Muro, Israel; Robertson, John D.; Wright, Casey W.; Bratton, Shawn B.

2014-01-01

Acute heat shock can induce apoptosis through a canonical pathway involving the upstream activation of caspase-2, followed by BID cleavage and stimulation of the intrinsic pathway. Herein, we report that the BH3-only protein BIM, rather than BID, is essential to heat shock-induced cell death. We observed that BIM-deficient cells were highly resistant to heat shock, exhibiting short and long-term survival equivalent to Bax−/−Bak−/− cells and better than either Bid−/− or dominant-negative caspase-9-expressing cells. Only Bim−/− and Bax−/−Bak−/− cells exhibited resistance to mitochondrial outer membrane permeabilization and loss of mitochondrial inner membrane potential. Moreover, while dimerized caspase-2 failed to induce apoptosis in Bid−/− cells, it readily did so in Bim−/− cells, implying that caspase-2 kills exclusively through BID, not BIM. Finally, BIM reportedly associates with MCL-1 following heat shock, and Mcl-1−/− cells were indeed sensitized to heat shock-induced apoptosis. However, pharmacological inhibition of BCL-2 and BCL-XL with ABT-737 also sensitized cells to heat shock, most likely through liberation of BIM. Thus, BIM mediates heat shock-induced apoptosis through a BAX/BAK-dependent pathway that is antagonized by antiapoptotic BCL-2 family members. PMID:24427286

Chromospheric heating by acoustic shock waves

NASA Technical Reports Server (NTRS)

Jordan, Stuart D.

1993-01-01

Work by Anderson & Athay (1989) suggests that the mechanical energy required to heat the quiet solar chromosphere might be due to the dissipation of weak acoustic shocks. The calculations reported here demonstrate that a simple picture of chromospheric shock heating by acoustic waves propagating upward through a model solar atmosphere, free of both magnetic fields and local inhomogeneities, cannot reproduce their chromospheric model. The primary reason is the tendency for vertically propagating acoustic waves in the range of allowed periods to dissipate too low in the atmosphere, providing insufficient residual energy for the middle chromosphere. The effect of diverging magnetic fields and the corresponding expanding acoustic wavefronts on the mechanical dissipation length is then discussed as a means of preserving a quasi-acoustic heating hypothesis. It is argued that this effect, in a canopy that overlies the low chromosphere, might preserve the acoustic shock hypothesis consistent with the chromospheric radiation losses computed by Anderson & Athay.

Heat-shock-specific phosphorylation and transcriptional activity of RNA polymerase II.

PubMed

Egyházi, E; Ossoinak, A; Lee, J M; Greenleaf, A L; Mäkelä, T P; Pigon, A

1998-07-10

The carboxyl-terminal domain (CTD) of the largest RNA polymerase II (pol II) subunit is a target for extensive phosphorylation in vivo. Using in vitro kinase assays it was found that several different protein kinases can phosphorylate the CTD including the transcription factor IIH-associated CDK-activating CDK7 kinase (R. Roy, J. P. Adamczewski, T. Seroz, W. Vermeulen, J. P. Tassan, L. Schaeffer, E. A. Nigg, J. H. Hoeijmakers, and J. M. Egly, 1994, Cell 79, 1093-1101). Here we report the colocalization of CDK7 and the phosphorylated form of CTD (phosphoCTD) to actively transcribing genes in intact salivary gland cells of Chironomus tentans. Following a heat-shock treatment, both CDK7 and pol II staining disappear from non-heat-shock genes concomitantly with the abolishment of transcriptional activity of these genes. In contrast, the actively transcribing heat-shock genes, manifested as chromosomal puff 5C on chromosome IV (IV-5C), stain intensely for phosphoCTD, but are devoid of CDK7. Furthermore, the staining of puff IV-5C with anti-PCTD antibodies was not detectably influenced by the TFIIH kinase and transcription inhibitor 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB). Following heat-shock treatment, the transcription of non-heat-shock genes was completely eliminated, while newly formed heat-shock gene transcripts emerged in a DRB-resistant manner. Thus, heat shock in these cells induces a rapid clearance of CDK7 from the non-heat-shock genes, indicating a lack of involvement of CDK7 in the induction and function of the heat-induced genes. The results taken together suggest the existence of heat-shock-specific CTD phosphorylation in living cells. This phosphorylation is resistant to DRB treatment, suggesting that not only phosphorylation but also transcription of heat-shock genes is DRB resistant and that CDK7 in heat shock cells is not associated with TFIIH.

Mechanical analysis of a heat-shock induced developmental defect

NASA Astrophysics Data System (ADS)

Crews, Sarah M.; McCleery, W. Tyler; Hutson, M. Shane

2014-03-01

Embryonic development in Drosophila is a complex process involving coordinated movements of mechanically interacting tissues. Perturbing this system with a transient heat shock can result in a number of developmental defects. In particular, a heat shock applied during the earliest morphogenetic movements of gastrulation can lead to apparent recovery, but then subsequent morphogenetic failure 5-6 hours later during germ band retraction. The process of germ band retraction requires an intact amnioserosa - a single layered extra-embryonic epithelial tissue - and heat shock at gastrulation can induce the later opening of holes in the amnioserosa. These holes are highly correlated with failures of germ band retraction. These holes could be caused by a combination of mechanical weakness in the amnioserosa or local increases in mechanical stress. Here, we assess the role of mechanical stress using confocal imaging to compare cell and tissue morphology in the amnioserosa of normal and heat-shocked embryos and laser hole drilling to map the stress field around the times and locations at which heat-shock induced holes open.

Convergence of the transcriptional responses to heat shock and singlet oxygen stresses.

PubMed

Dufour, Yann S; Imam, Saheed; Koo, Byoung-Mo; Green, Heather A; Donohue, Timothy J

2012-09-01

Cells often mount transcriptional responses and activate specific sets of genes in response to stress-inducing signals such as heat or reactive oxygen species. Transcription factors in the RpoH family of bacterial alternative σ factors usually control gene expression during a heat shock response. Interestingly, several α-proteobacteria possess two or more paralogs of RpoH, suggesting some functional distinction. We investigated the target promoters of Rhodobacter sphaeroides RpoH(I) and RpoH(II) using genome-scale data derived from gene expression profiling and the direct interactions of each protein with DNA in vivo. We found that the RpoH(I) and RpoH(II) regulons have both distinct and overlapping gene sets. We predicted DNA sequence elements that dictate promoter recognition specificity by each RpoH paralog. We found that several bases in the highly conserved TTG in the -35 element are important for activity with both RpoH homologs; that the T-9 position, which is over-represented in the RpoH(I) promoter sequence logo, is critical for RpoH(I)-dependent transcription; and that several bases in the predicted -10 element were important for activity with either RpoH(II) or both RpoH homologs. Genes that are transcribed by both RpoH(I) and RpoH(II) are predicted to encode for functions involved in general cell maintenance. The functions specific to the RpoH(I) regulon are associated with a classic heat shock response, while those specific to RpoH(II) are associated with the response to the reactive oxygen species, singlet oxygen. We propose that a gene duplication event followed by changes in promoter recognition by RpoH(I) and RpoH(II) allowed convergence of the transcriptional responses to heat and singlet oxygen stress in R. sphaeroides and possibly other bacteria.

Heat Shock Response of Archaeoglobus fulgidus†

PubMed Central

Rohlin, Lars; Trent, Jonathan D.; Salmon, Kirsty; Kim, Unmi; Gunsalus, Robert P.; Liao, James C.

2005-01-01

The heat shock response of the hyperthermophilic archaeon Archaeoglobus fulgidus strain VC-16 was studied using whole-genome microarrays. On the basis of the resulting expression profiles, approximately 350 of the 2,410 open reading frames (ORFs) (ca. 14%) exhibited increased or decreased transcript abundance. These span a range of cell functions, including energy production, amino acid metabolism, and signal transduction, where the majority are uncharacterized. One ORF called AF1298 was identified that contains a putative helix-turn-helix DNA binding motif. The gene product, HSR1, was expressed and purified from Escherichia coli and was used to characterize specific DNA recognition regions upstream of two A. fulgidus genes, AF1298 and AF1971. The results indicate that AF1298 is autoregulated and is part of an operon with two downstream genes that encode a small heat shock protein, Hsp20, and cdc48, an AAA+ ATPase. The DNase I footprints using HSR1 suggest the presence of a cis-binding motif upstream of AF1298 consisting of CTAAC-N5-GTTAG. Since AF1298 is negatively regulated in response to heat shock and encodes a protein only distantly related to the N-terminal DNA binding domain of Phr of Pyrococcus furiosus, these results suggest that HSR1 and Phr may belong to an evolutionarily diverse protein family involved in heat shock regulation in hyperthermophilic and mesophilic Archaea organisms. PMID:16109946

Selective activation of human heat shock gene transcription by nitrosourea antitumor drugs mediated by isocyanate-induced damage and activation of heat shock transcription factor.

PubMed Central

Kroes, R A; Abravaya, K; Seidenfeld, J; Morimoto, R I

1991-01-01

Treatment of cultured human tumor cells with the chloroethylnitrosourea antitumor drug 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) selectively induces transcription and protein synthesis of a subset of the human heat shock or stress-induced genes (HSP90 and HSP70) with little effect on other stress genes or on expression of the c-fos, c-myc, or beta-actin genes. The active component of BCNU and related compounds appears to be the isocyanate moiety that causes carbamoylation of proteins and nucleic acids. Transcriptional activation of the human HSP70 gene by BCNU is dependent on the heat shock element and correlates with the level of heat shock transcription factor and its binding to the heat shock element in vivo. Unlike activation by heat or heavy metals, BCNU-mediated activation is strongly dependent upon new protein synthesis. This suggests that BCNU-induced, isocyanate-mediated damage to newly synthesized protein(s) may be responsible for activation of the heat shock transcription factor and increased transcription of the HSP90 and HSP70 genes. Images PMID:2052560

Uncoupling thermotolerance from the induction of heat shock proteins.

PubMed Central

Smith, B J; Yaffe, M P

1991-01-01

Exposure of cells to elevated temperatures causes a rapid increase in the synthesis of heat shock proteins (hsps) and induces thermotolerance, the increased ability of cells to survive exposure to lethal temperatures; however, the connection between hsp induction and the acquisition of thermotolerance is unclear. hsp induction in the yeast Saccharomyces cerevisiae is mediated by the activation of heat-shock transcription factor, and recently we have described a mutation, hsf1-m3, in heat-shock transcription factor that prevents the factor's activation. We now demonstrate that this mutation results in a general block in heat-shock induction but does not affect the acquisition of thermotolerance. Our results indicate that high-level induction of the major hsps is not required for cells to acquire thermotolerance. Images PMID:1763024

Automated Scalable Heat Shock Modification for Standard Aquatic Housing Systems.

PubMed

Saera-Vila, Alfonso; Kish, Phillip E; Kahana, Alon

2015-08-01

Heat shock is a common technique for inducible gene expression system in a variety of organisms. Heat shock treatment of adult zebrafish is more involved and generally consists of manually transferring fish between housing rack tanks and preheated water tanks or the use of timed heaters in stand-alone aquaria. To avoid excessive fish handling and to take advantage of the continuous flow of a standard housing rack, proposed modifications consisted of installing an aquarium heater inside each tank, manually setting the heater to reach heat shocking temperatures (> 37°C) and, after that, testing that every tank responded equally. To address the limitations in the existing systems, we developed a novel modification of standard zebrafish housing racks to perform heat shock treatment in conditions of continuous water flow. By adding an extra manifold to the housing rack and connecting it to a recirculating bath to create a parallel water flow system, we can increase the temperature from standard conditions (28.5°C) to heat shock conditions with high precision (38.0-38.3°C, mean ± SD = 38.1°C ± 0.14°C) and minimal variation among experimental tanks (coefficient of variation [CV] = 0.04%). This means that there is virtually no need for laborious pretreatment calibrations or continuous adjustments to minimize intertank variation. To test the effectiveness of our design, we utilized this system to induce enhanced green fluorescent protein (EGFP) expression in hsp70-EGFP fish and performed a fin regeneration experiment with hsp70l:dnfgfr1-EGFP fish to confirm that heat-induced gene expression reached physiological levels. In summary, our newly described aquatic heat shock system minimizes effort during heat shock experiments, while ensuring the best water quality and fish welfare and facilitating large heat shock settings or the use of multiple transgenic lines for both research and teaching experiments.

Synthesis of the low molecular weight heat shock proteins in plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mansfield, M.A.; Key, J.L.

1987-08-01

Heat shock of living tissue induces the synthesis of a unique group of proteins, the heat shock proteins. In plants, the major group of heat shock proteins has a molecular mass of 15 to 25 kilodaltons. Accumulation to these proteins to stainable levels has been reported in only a few species. To examine accumulation of the low molecular weight heat shock proteins in a broader range of species, two-dimensional electrophoresis was used to resolve total protein from the following species: soybean (Glycine max L. Merr., var Wayne), pea (Pisum sativum L., var Early Alaska), sunflower (Helianthus annuus L.), wheat (Triticummore » asetivum L.), rice (Oryza sativa L., cv IR-36), maize (Zea mays L.), pearl millet (Pennisetum americanum L. Leeke, line 23DB), and Panicum miliaceum L. When identified by both silver staining and incorporation of radiolabel, a diverse array of low molecular weight heat shock proteins was synthesized in each of these species. These proteins accumulated to significant levels after three hours of heat shock but exhibited considerable heterogeneity in isoelectric point, molecular weight, stainability, and radiolabel incorporation. Although most appeared to be synthesized only during heat shock, some were detectable at low levels in control tissue. Compared to the monocots, a higher proportion of low molecular weight heat shock proteins was detectable in control tissues from dicots.« less

Destabilization and recovery of a yeast prion after mild heat shock

PubMed Central

Newnam, Gary P.; Birchmore, Jennifer L.; Chernoff, Yury O.

2011-01-01

Yeast prion [PSI+] is a self-perpetuating amyloid of the translational termination factor Sup35. Although [PSI+] propagation is modulated by heat shock proteins (Hsps), high temperature was previously reported to have little or no effect on [PSI+]. Our results show that short-term exposure of exponentially growing yeast culture to mild heat shock, followed by immediate resumption of growth, leads to [PSI+] destabilization, sometimes persisting for several cell divisions after heat shock. Prion loss occurring in the first division after heat shock is preferentially detected in a daughter cell, indicating the impairment of prion segregation that results in asymmetric prion distribution between a mother cell and a bud. Longer heat shock or prolonged incubation in the absence of nutrients after heat shock lead to [PSI+] recovery. Both prion destabilization and recovery during heat shock depend on protein synthesis. Maximal prion destabilization coincides with maximal imbalance between Hsp104 and other Hsps such as Hsp70-Ssa. Deletions of individual SSA genes increase prion destabilization and/or counteract recovery. Dynamics of prion aggregation during destabilization and recovery is consistent with the notion that efficient prion fragmentation and segregation require a proper balance between Hsp104 and other (e. g. Hsp70-Ssa) chaperones. In contrast to heat shock, [PSI+] destabilization by osmotic stressors does not always depend on cell proliferation and/or protein synthesis, indicating that different stresses may impact the prion via different mechanisms. Our data demonstrate that heat stress causes asymmetric prion distribution in a cell division, and confirm that effects of Hsps on prions are physiologically relevant. PMID:21392508

Glutamine's protection against cellular injury is dependent on heat shock factor-1.

PubMed

Morrison, Angela L; Dinges, Martin; Singleton, Kristen D; Odoms, Kelli; Wong, Hector R; Wischmeyer, Paul E

2006-06-01

Glutamine (GLN) has been shown to protect cells, tissues, and whole organisms from stress and injury. Enhanced expression of heat shock protein (HSP) has been hypothesized to be responsible for this protection. To date, there are no clear mechanistic data confirming this relationship. This study tested the hypothesis that GLN-mediated activation of the HSP pathway via heat shock factor-1 (HSF-1) is responsible for cellular protection. Wild-type HSF-1 (HSF-1(+/+)) and knockout (HSF-1(-/-)) mouse fibroblasts were used in all experiments. Cells were treated with GLN concentrations ranging from 0 to 16 mM and exposed to heat stress injury in a concurrent treatment model. Cell viability was assayed with phenazine methosulfate plus tetrazolium salt, HSP-70, HSP-25, and nuclear HSF-1 expression via Western blot analysis, and HSF-1/heat shock element (HSE) binding via EMSA. GLN significantly attenuated heat-stress induced cell death in HSF-1(+/+) cells in a dose-dependent manner; however, the survival benefit of GLN was lost in HSF-1(-/-) cells. GLN led to a dose-dependent increase in HSP-70 and HSP-25 expression after heat stress. No inducible HSP expression was observed in HSF-1(-/-) cells. GLN increased unphosphorylated HSF-1 in the nucleus before heat stress. This was accompanied by a GLN-mediated increase in HSF-1/HSE binding and nuclear content of phosphorylated HSF-1 after heat stress. This is the first demonstration that GLN-mediated cellular protection after heat-stress injury is related to HSF-1 expression and cellular capacity to activate an HSP response. Furthermore, the mechanism of GLN-mediated protection against injury appears to involve an increase in nuclear HSF-1 content before stress and increased HSF-1 promoter binding and phosphorylation.

Biophoton Emission Induced by Heat Shock

PubMed Central

Kobayashi, Katsuhiro; Okabe, Hirotaka; Kawano, Shinya; Hidaka, Yoshiki; Hara, Kazuhiro

2014-01-01

Ultraweak biophoton emission originates from the generation of reactive oxygen species (ROS) that are produced in mitochondria as by-products of cellular respiration. In healthy cells, the concentration of ROS is minimized by a system of biological antioxidants. However, heat shock changes the equilibrium between oxidative stress and antioxidant activity, that is, a rapid rise in temperature induces biophoton emission from ROS. Although the rate and intensity of biophoton emission was observed to increase in response to elevated temperatures, pretreatment at lower high temperatures inhibited photon emission at higher temperatures. Biophoton measurements are useful for observing and evaluating heat shock. PMID:25153902

The natural compound cantharidin induces cancer cell death through inhibition of heat shock protein 70 (HSP70) and Bcl-2-associated athanogene domain 3 (BAG3) expression by blocking heat shock factor 1 (HSF1) binding to promoters.

PubMed

Kim, Joo Ae; Kim, Youngmi; Kwon, Byoung-Mog; Han, Dong Cho

2013-10-04

Heat shock factor 1 (HSF1) enhances the survival of cancer cells under various stresses. The knock-out of HSF1 impairs cancer formation and progression, suggesting that HSF1 is a promising therapeutic target. To identify inhibitors of HSF1 activity, we performed cell-based screening with a library of marketed and experimental drugs and identified cantharidin as an HSF1 inhibitor. Cantharidin is a potent antitumor agent from traditional Chinese medicine. Cantharidin inhibited heat shock-induced luciferase activity with an IC50 of 4.2 μm. In contrast, cantharidin did not inhibit NF-κB luciferase reporter activity, demonstrating that cantharidin is not a general transcription inhibitor. When the HCT-116 colorectal cancer cells were exposed to heat shock in the presence of cantharidin, the induction of HSF1 downstream target proteins, such as HSP70 and BAG3 (Bcl-2-associated athanogene domain 3), was suppressed. HSP70 and its co-chaperone BAG3 have been reported to protect cells from apoptosis by stabilizing anti-apoptotic Bcl-2 family proteins. As expected, treating HCT-116 cancer cells with cantharidin significantly decreased the amounts of BCL-2, BCL-xL, and MCL-1 protein and induced apoptotic cell death. Chromatin immunoprecipitation analysis showed that cantharidin inhibited the binding of HSF1 to the HSP70 promoter and subsequently blocked HSF1-dependent p-TEFb recruitment. Therefore, the p-TEFb-dependent phosphorylation of the C-terminal domain of RNA polymerase II was blocked, arresting transcription at the elongation step. Protein phosphatase 2A inhibition with PP2CA siRNA or okadaic acid did not block HSF1 activity, suggesting that cantharidin inhibits HSF1 in a protein phosphatase 2A-independent manner. We show for the first time that cantharidin inhibits HSF1 transcriptional activity.

Engagement of Components of DNA-Break Repair Complex and NFκB in Hsp70A1A Transcription Upregulation by Heat Shock.

PubMed

Hazra, Joyita; Mukherjee, Pooja; Ali, Asif; Poddar, Soumita; Pal, Mahadeb

2017-01-01

An involvement of components of DNA-break repair (DBR) complex including DNA-dependent protein kinase (DNA-PK) and poly-ADP-ribose polymerase 1 (PARP-1) in transcription regulation in response to distinct cellular signalling has been revealed by different laboratories. Here, we explored the involvement of DNA-PK and PARP-1 in the heat shock induced transcription of Hsp70A1A. We find that inhibition of both the catalytic subunit of DNA-PK (DNA-PKc), and Ku70, a regulatory subunit of DNA-PK holo-enzyme compromises transcription of Hsp70A1A under heat shock treatment. In immunoprecipitation based experiments we find that Ku70 or DNA-PK holoenzyme associates with NFκB. This NFκB associated complex also carries PARP-1. Downregulation of both NFκB and PARP-1 compromises Hsp70A1A transcription induced by heat shock treatment. Alteration of three bases by site directed mutagenesis within the consensus κB sequence motif identified on the promoter affected inducibility of Hsp70A1A transcription by heat shock treatment. These results suggest that NFκB engaged with the κB motif on the promoter cooperates in Hsp70A1A activation under heat shock in human cells as part of a DBR complex including DNA-PK and PARP-1.

Automated Scalable Heat Shock Modification for Standard Aquatic Housing Systems

PubMed Central

Saera-Vila, Alfonso; Kish, Phillip E.

2015-01-01

Abstract Heat shock is a common technique for inducible gene expression system in a variety of organisms. Heat shock treatment of adult zebrafish is more involved and generally consists of manually transferring fish between housing rack tanks and preheated water tanks or the use of timed heaters in stand-alone aquaria. To avoid excessive fish handling and to take advantage of the continuous flow of a standard housing rack, proposed modifications consisted of installing an aquarium heater inside each tank, manually setting the heater to reach heat shocking temperatures (>37°C) and, after that, testing that every tank responded equally. To address the limitations in the existing systems, we developed a novel modification of standard zebrafish housing racks to perform heat shock treatment in conditions of continuous water flow. By adding an extra manifold to the housing rack and connecting it to a recirculating bath to create a parallel water flow system, we can increase the temperature from standard conditions (28.5°C) to heat shock conditions with high precision (38.0–38.3°C, mean±SD=38.1°C±0.14°C) and minimal variation among experimental tanks (coefficient of variation [CV]=0.04%). This means that there is virtually no need for laborious pretreatment calibrations or continuous adjustments to minimize intertank variation. To test the effectiveness of our design, we utilized this system to induce enhanced green fluorescent protein (EGFP) expression in hsp70-EGFP fish and performed a fin regeneration experiment with hsp70l:dnfgfr1-EGFP fish to confirm that heat-induced gene expression reached physiological levels. In summary, our newly described aquatic heat shock system minimizes effort during heat shock experiments, while ensuring the best water quality and fish welfare and facilitating large heat shock settings or the use of multiple transgenic lines for both research and teaching experiments. PMID:25942613

Destabilization and recovery of a yeast prion after mild heat shock.

PubMed

Newnam, Gary P; Birchmore, Jennifer L; Chernoff, Yury O

2011-05-06

Yeast prion [PSI(+)] is a self-perpetuating amyloid of the translational termination factor Sup35. Although [PSI(+)] propagation is modulated by heat shock proteins (Hsps), high temperature was previously reported to have little or no effect on [PSI(+)]. Our results show that short-term exposure of exponentially growing yeast culture to mild heat shock, followed by immediate resumption of growth, leads to [PSI(+)] destabilization, sometimes persisting for several cell divisions after heat shock. Prion loss occurring in the first division after heat shock is preferentially detected in a daughter cell, indicating the impairment of prion segregation that results in asymmetric prion distribution between a mother cell and a bud. Longer heat shock or prolonged incubation in the absence of nutrients after heat shock led to [PSI(+)] recovery. Both prion destabilization and recovery during heat shock depend on protein synthesis. Maximal prion destabilization coincides with maximal imbalance between Hsp104 and other Hsps such as Hsp70-Ssa. Deletions of individual SSA genes increase prion destabilization and/or counteract recovery. The dynamics of prion aggregation during destabilization and recovery are consistent with the notion that efficient prion fragmentation and segregation require a proper balance between Hsp104 and other (e.g., Hsp70-Ssa) chaperones. In contrast to heat shock, [PSI(+)] destabilization by osmotic stressors does not always depend on cell proliferation and/or protein synthesis, indicating that different stresses may impact the prion via different mechanisms. Our data demonstrate that heat stress causes asymmetric prion distribution in a cell division and confirm that the effects of Hsps on prions are physiologically relevant. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of several factors on the heat-shock-induced thermotolerance of Listeria monocytogenes.

PubMed Central

Pagán, R; Condón, S; Sala, F J

1997-01-01

The influence of the temperature at which Listeria monocytogenes had been grown (4 or 37 degrees C) on the response to heat shocks of different durations at different temperatures was investigated. For cells grown at 4 degrees C, the effect of storage, prior to and after heat shock, on the induced thermotolerance was also studied. Death kinetics of heat-shocked cells is also discussed. For L. monocytogenes grown at 37 degrees C, the greatest response to heat shock was a fourfold increase in thermotolerance. For L. monocytogenes grown at 4 degrees C, the greatest response to heat shock was a sevenfold increase in thermotolerance. The only survival curves of cells to have shoulders were those for cells that had been heat shocked. A 3% concentration of sodium chloride added to the recovery medium made these shoulders disappear and decreased decimal reduction times. The percentage of cells for which thermotolerance increased after a heat shock was smaller the milder the heat shock and the longer the prior storage. PMID:9251209

Methyl CpG level at distal part of heat-shock protein promoter HSP70 exhibits epigenetic memory for heat stress by modulating recruitment of POU2F1-associated nucleosome-remodeling deacetylase (NuRD) complex.

PubMed

Kisliouk, Tatiana; Cramer, Tomer; Meiri, Noam

2017-05-01

Depending on its stringency, exposure to heat in early life leads to either resilience or vulnerability to heat stress later in life. We hypothesized that epigenetic alterations in genes belonging to the cell proteostasis pathways are attributed to long-term responses to heat stress. Epigenetic regulation of the mRNA expression of the molecular chaperone heat-shock protein (HSP) 70 (HSPA2) was evaluated in the chick hypothalamus during the critical period of thermal-control establishment on day 3 post-hatch and during heat challenge on day 10. Both the level and duration of HSP70 expression during heat challenge a week after heat conditioning were more pronounced in chicks conditioned under harsh versus mild temperature. Analyzing different segments of the promoter in vitro indicated that methylation of a distal part altered its transcriptional activity. In parallel, DNA-methylation level of this segment in vivo was higher in harsh- compared to mild-heat-conditioned chicks. Hypermethylation of the HSP70 promoter in high-temperature-conditioned chicks was accompanied by a reduction in both POU Class 2 Homeobox 1 (POU2F1) binding and recruitment of the nucleosome remodeling deacetylase (NuRD) chromatin-remodeling complex. As a result, histone H3 acetylation levels at the HSP70 promoter were higher in harsh-temperature-conditioned chicks than in their mild-heat-conditioned counterparts. These results suggest that methylation level of a distal part of the HSP70 promoter and POU2F1 recruitment may reflect heat-stress-related epigenetic memory and may be useful in differentiating between individuals that are resilient or vulnerable to stress. © 2017 International Society for Neurochemistry.

Effects of wake and shock passing on the heat transfer to a film cooled transonic turbine blade

NASA Astrophysics Data System (ADS)

Rigby, M. J.

An attempt is made to further the understanding of film cooling process in an engine environment. The environment in a gas turbine is unsteady. A source of unsteadiness, the cutting of nozzle guide vane (NGV) wakes and shock waves by the rotor, was modeled experimentally. The influence of the unsteady wakes and shock waves on the heat transfer to a film cooled rotor blade was studied for five film cooling configurations using a rotating bar apparatus in front of a 2-D cascade. Heat transfer measurements were made using thin film gauges placed at the mid-span of the test blade. Schlieren photography was used to study the behavior of the coolant film and the movement of the unsteady shock waves and wakes. The effect of simulated NGV wake passing observed on the uncooled airfoil is to promote an intermittent transition of the suction surface. The effect of the wake on the turbulent pressure surface is small. With injection on the suction surface, the film acts as a boundary layer trip which offsets the rise in heat transfer due to the wake. The simulated NGV trailing edge shock wave had a dramatic effect on the suction surface heat transfer.

Increased temperature, not cardiac load, activates heat shock transcription factor 1 and heat shock protein 72 expression in the heart.

PubMed

Staib, Jessica L; Quindry, John C; French, Joel P; Criswell, David S; Powers, Scott K

2007-01-01

The expression of myocardial heat shock protein 72 (HSP72) postexercise is initiated by the activation of heat shock transcription factor 1 (HSF1). However, it remains unknown which physiological stimuli govern myocardial HSF1 activation during exercise. These experiments tested the hypothesis that thermal stress and mechanical load, concomitant with simulated exercise, provide independent stimuli for HSF1 activation and ensuing cardiac HSP72 gene expression. To elucidate the independent roles of increased temperature and cardiac workload in the exercise-mediated upregulation of left-ventricular HSP72, hearts from adult male Sprague-Dawley rats were randomly assigned to one of five simulated exercise conditions. Upon reaching a surgical plane of anesthesia, each experimental heart was isolated and perfused using an in vitro working heart model, while independently varying temperatures (i.e., 37 degrees C vs. 40 degrees C) and cardiac workloads (i.e., low preload and afterload vs. high preload and afterload) to mimic exercise responses. Results indicate that hyperthermia, independent of cardiac workload, promoted an increase in nuclear translocation and phosphorylation of HSF1 compared with normothermic left ventricles. Similarly, hyperthermia, independent of workload, resulted in significant increases in cardiac levels of HSP72 mRNA. Collectively, these data suggest that HSF1 activation and HSP72 gene transcriptional competence during simulated exercise are linked to elevated heart temperature and are not a direct function of increased cardiac workload.

Quality of cut lettuce treated by heat shock: prevention of enzymatic browning, repression of phenylalanine ammonia-lyase activity, and improvement on sensory evaluation during storage.

PubMed

Murata, Masatsune; Tanaka, Eriko; Minoura, Emiko; Homma, Seiichi

2004-03-01

Stored cut lettuce gradually turns brown on the cut section after several days of storage, because cutting induces phenylalanine ammonia-lyase (PAL) activity, the biosynthesis of polyphenol is promoted, and the polyphenols are oxidized by polyphenol oxidase. Here, the effect of heat shock treatment at 50 degrees C for 90 s on the quality of cut lettuce during cold storage was examined. The heat shock treatment significantly repressed the induction of PAL activity and phenolics accumulation in cut lettuce during storage, and prevented the browning of cut lettuce. Ascorbic acid content was not affected by the heat shock treatment. The sensory analysis showed that the organoleptic quality of cut lettuce treated by heat shock was significantly better than that of the control cut lettuce. These results show that heat shock treatment is useful for prolonging the shelf life of cut lettuce.

Calving traits of crossbred Brahman Cows are Associated with Heat Shock Protein 70 Genetic Polymorphisms

USDA-ARS?s Scientific Manuscript database

Objectives were to: 1) identify single nucleotide polymorphisms (SNP) located in the promoter region of the bovine heat shock protein 70 gene, and 2) evaluate associations between Hsp70 SNP and calving rates of Brahman-influenced cows. Specific primers were designed for PCR amplification of a 539 b...

Heat Shock-Enhanced Conjugation Efficiency in Standard Campylobacter jejuni Strains

PubMed Central

Zeng, Ximin; Ardeshna, Devarshi

2015-01-01

Campylobacter jejuni, the leading bacterial cause of human gastroenteritis in the United States, displays significant strain diversity due to horizontal gene transfer. Conjugation is an important horizontal gene transfer mechanism contributing to the evolution of bacterial pathogenesis and antimicrobial resistance. It has been observed that heat shock could increase transformation efficiency in some bacteria. In this study, the effect of heat shock on C. jejuni conjugation efficiency and the underlying mechanisms were examined. With a modified Escherichia coli donor strain, different C. jejuni recipient strains displayed significant variation in conjugation efficiency ranging from 6.2 × 10−8 to 6.0 × 10−3 CFU per recipient cell. Despite reduced viability, heat shock of standard C. jejuni NCTC 11168 and 81-176 strains (e.g., 48 to 54°C for 30 to 60 min) could dramatically enhance C. jejuni conjugation efficiency up to 1,000-fold. The phenotype of the heat shock-enhanced conjugation in C. jejuni recipient cells could be sustained for at least 9 h. Filtered supernatant from the heat shock-treated C. jejuni cells could not enhance conjugation efficiency, which suggests that the enhanced conjugation efficiency is independent of secreted substances. Mutagenesis analysis indicated that the clustered regularly interspaced short palindromic repeats system and the selected restriction-modification systems (Cj0030/Cj0031, Cj0139/Cj0140, Cj0690c, and HsdR) were dispensable for heat shock-enhanced conjugation in C. jejuni. Taking all results together, this study demonstrated a heat shock-enhanced conjugation efficiency in standard C. jejuni strains, leading to an optimized conjugation protocol for molecular manipulation of this organism. The findings from this study also represent a significant step toward elucidation of the molecular mechanism of conjugative gene transfer in C. jejuni. PMID:25911489

Heat Shock-Enhanced Conjugation Efficiency in Standard Campylobacter jejuni Strains.

PubMed

Zeng, Ximin; Ardeshna, Devarshi; Lin, Jun

2015-07-01

Campylobacter jejuni, the leading bacterial cause of human gastroenteritis in the United States, displays significant strain diversity due to horizontal gene transfer. Conjugation is an important horizontal gene transfer mechanism contributing to the evolution of bacterial pathogenesis and antimicrobial resistance. It has been observed that heat shock could increase transformation efficiency in some bacteria. In this study, the effect of heat shock on C. jejuni conjugation efficiency and the underlying mechanisms were examined. With a modified Escherichia coli donor strain, different C. jejuni recipient strains displayed significant variation in conjugation efficiency ranging from 6.2 × 10(-8) to 6.0 × 10(-3) CFU per recipient cell. Despite reduced viability, heat shock of standard C. jejuni NCTC 11168 and 81-176 strains (e.g., 48 to 54°C for 30 to 60 min) could dramatically enhance C. jejuni conjugation efficiency up to 1,000-fold. The phenotype of the heat shock-enhanced conjugation in C. jejuni recipient cells could be sustained for at least 9 h. Filtered supernatant from the heat shock-treated C. jejuni cells could not enhance conjugation efficiency, which suggests that the enhanced conjugation efficiency is independent of secreted substances. Mutagenesis analysis indicated that the clustered regularly interspaced short palindromic repeats system and the selected restriction-modification systems (Cj0030/Cj0031, Cj0139/Cj0140, Cj0690c, and HsdR) were dispensable for heat shock-enhanced conjugation in C. jejuni. Taking all results together, this study demonstrated a heat shock-enhanced conjugation efficiency in standard C. jejuni strains, leading to an optimized conjugation protocol for molecular manipulation of this organism. The findings from this study also represent a significant step toward elucidation of the molecular mechanism of conjugative gene transfer in C. jejuni. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Extracellular small heat shock proteins: exosomal biogenesis and function.

PubMed

Reddy, V Sudhakar; Madala, Satish K; Trinath, Jamma; Reddy, G Bhanuprakash

2018-05-01

Small heat shock proteins (sHsps) belong to the family of heat shock proteins (Hsps): some are induced in response to multiple stressful events to protect the cells while others are constitutively expressed. Until now, it was believed that Hsps, including sHsps, are present inside the cells and perform intracellular functions. Interestingly, several groups recently reported the extracellular presence of Hsps, and sHsps have also been detected in sera/cerebrospinal fluids in various pathological conditions. Secretion into the extracellular milieu during many pathological conditions suggests additional or novel functions of sHsps in addition to their intracellular properties. Extracellular sHsps are implicated in cell-cell communication, activation of immune cells, and promoting anti-inflammatory and anti-platelet responses. Interestingly, exogenous administration of sHsps showed therapeutic effects in multiple disease models implying that extracellular sHsps are beneficial in pathological conditions. sHsps do not possess signal sequence and, hence, are not exported through the classical Endoplasmic reticulum-Golgi complex (ER-Golgi) secretory pathway. Further, export of sHsps is not inhibited by ER-Golgi secretory pathway inhibitors implying the involvement of a nonclassical secretory pathway in sHsp export. In lieu, lysoendosomal and exosomal pathways have been proposed for the export of sHsps. Heat shock protein 27 (Hsp27), αB-crystallin (αBC), and Hsp20 are shown to be exported by exosomes. Exosomes packaged with sHsps have beneficial effects in in vivo disease models. However, secretion mechanisms and therapeutic use of sHsps have not been elucidated in detail. Therefore, this review aimed at highlighting the current understanding of sHsps (Hsp27, αBC, and Hsp20) in the extracellular medium.

Heat shock protein-containing exosomes in mid-trimester amniotic fluids.

PubMed

Asea, Alexzander; Jean-Pierre, Claudel; Kaur, Punit; Rao, Preethi; Linhares, Iara M; Skupski, Daniel; Witkin, Steven S

2008-10-01

Exosomes are multivesicular bodies formed by inverse membrane budding into the lumen of an endocytic compartment. Fusion with the plasma membrane leads to their release into the external milieu. The incorporation of heat shock proteins into exosomes has been associated with immune regulatory activity. We have examined whether heat shock protein-containing exosomes are present in mid-trimester amniotic fluid. Exosomes were isolated from mid-trimester amniotic fluids by sequential low-speed and high-speed centrifugation followed by sucrose density gradient centrifugation. Biochemical characterization included floatation pattern in sucrose gradients, acetylcholinesterase (AChE) activity and Western blot analysis for exosome-containing proteins. Exosomes were present in each of 23 amniotic fluids tested. They banded at a density of 1.17g/ml in sucrose gradients, were positive for AChE activity and contained tubulin, the inducible 72kDa heat shock protein, Hsp72 and the constitutively expressed heat shock protein, Hsc73; they were negative for calnexin. Exosome concentrations correlated positively with the number of pregnancies. Heat shock protein-containing exosomes are constituents of mid-trimester amniotic fluids and may contribute to immune regulation within the amniotic cavity.

Possible Contribution of Zerumbone-Induced Proteo-Stress to Its Anti-Inflammatory Functions via the Activation of Heat Shock Factor 1.

PubMed

Igarashi, Yoko; Ohnishi, Kohta; Irie, Kazuhiro; Murakami, Akira

2016-01-01

Zerumbone is a sesquiterpene present in Zinger zerumbet. Many studies have demonstrated its marked anti-inflammatory and anti-carcinogenesis activities. Recently, we showed that zerumbone binds to numerous proteins with scant selectivity and induces the expression of heat shock proteins (HSPs) in hepatocytes. To dampen proteo-toxic stress, organisms have a stress-responsive molecular machinery, known as heat shock response. Heat shock factor 1 (HSF1) plays a key role in this protein quality control system by promoting activation of HSPs. In this study, we investigated whether zerumbone-induced HSF1 activation contributes to its anti-inflammatory functions in stimulated macrophages. Our findings showed that zerumbone increased cellular protein aggregates and promoted nuclear translocation of HSF1 for HSP expression. Interestingly, HSF1 down-regulation attenuated the suppressive effects of zerumbone on mRNA and protein expressions of pro-inflammatory genes, including inducible nitric oxide synthase and interlukin-1β. These results suggest that proteo-stress induced by zerumbone activates HSF1 for exhibiting its anti-inflammatory functions.

The Heat Shock Response and Acute Lung Injury

PubMed Central

Wheeler, Derek S.; Wong, Hector R.

2006-01-01

All cells respond to stress through the activation of primitive, evolutionarily conserved genetic programs that maintain homeostasis and assure cell survival. Stress adaptation, which is known in the literature by a myriad of terms, including tolerance, desensitization, conditioning, and reprogramming, is a common paradigm found throughout nature, in which a primary exposure of a cell or organism to a stressful stimulus (e.g., heat) results in an adaptive response by which a second exposure to the same stimulus produces a minimal response. More interesting is the phenomenon of cross-tolerance, by which a primary exposure to a stressful stimulus results in an adaptive response whereby the cell or organism is resistant to a subsequent stress that is different from the initial stress (i.e. exposure to heat stress leading to resistance to oxidant stress). The heat shock response is one of the more commonly described examples of stress adaptation and is characterized by the rapid expression of a unique group of proteins collectively known as heat shock proteins (also commonly referred to as stress proteins). The expression of heat shock proteins is well described in both whole lungs and in specific lung cells from a variety of species and in response to a variety of stressors. More importantly, in vitro data, as well as data from various animal models of acute lung injury, demonstrate that heat shock proteins, especially Hsp27, Hsp32, Hsp60, and Hsp70 have an important cytoprotective role during lung inflammation and injury. PMID:17157189

Unraveling Regulation of the Small Heat Shock Proteins by the Heat Shock Factor HvHsfB2c in Barley: Its Implications in Drought Stress Response and Seed Development

PubMed Central

Reddy, Palakolanu Sudhakar; Kavi Kishor, Polavarapu B.; Seiler, Christiane; Kuhlmann, Markus; Eschen-Lippold, Lennart; Lee, Justin; Reddy, Malireddy K.; Sreenivasulu, Nese

2014-01-01

The rapid increase in heat shock proteins upon exposure to damaging stresses and during plant development related to desiccation events reveal their dual importance in plant development and stress tolerance. Genome-wide sequence survey identified 20 non-redundant small heat shock proteins (sHsp) and 22 heat shock factor (Hsf) genes in barley. While all three major classes (A, B, C) of Hsfs are localized in nucleus, the 20 sHsp gene family members are localized in different cell organelles like cytoplasm, mitochondria, plastid and peroxisomes. Hsf and sHsp members are differentially regulated during drought and at different seed developmental stages suggesting the importance of chaperone role under drought as well as seed development. In silico cis-regulatory motif analysis of Hsf promoters showed an enrichment with abscisic acid responsive cis-elements (ABRE), implying regulatory role of ABA in mediating transcriptional response of HvsHsf genes. Gene regulatory network analysis identified HvHsfB2c as potential central regulator of the seed-specific expression of several HvsHsps including 17.5CI sHsp. These results indicate that HvHsfB2c is co-expressed in the central hub of small Hsps and therefore it may be regulating the expression of several HvsHsp subclasses HvHsp16.88-CI, HvHsp17.5-CI and HvHsp17.7-CI. The in vivo relevance of binding specificity of HvHsfB2C transcription factor to HSE-element present in the promoter of HvSHP17.5-CI under heat stress exposure is confirmed by gel shift and LUC-reporter assays. Further, we isolated 477 bp cDNA from barley encoding a 17.5 sHsp polypeptide, which was predominantly upregulated under drought stress treatments and also preferentially expressed in developing seeds. Recombinant HvsHsp17.5-CI protein was expressed in E. coli and purified to homogeneity, which displayed in vitro chaperone activity. The predicted structural model of HvsHsp-17.5-CI protein suggests that the α-crystallin domain is evolutionarily highly

Unraveling regulation of the small heat shock proteins by the heat shock factor HvHsfB2c in barley: its implications in drought stress response and seed development.

PubMed

Reddy, Palakolanu Sudhakar; Kavi Kishor, Polavarapu B; Seiler, Christiane; Kuhlmann, Markus; Eschen-Lippold, Lennart; Lee, Justin; Reddy, Malireddy K; Sreenivasulu, Nese

2014-01-01

The rapid increase in heat shock proteins upon exposure to damaging stresses and during plant development related to desiccation events reveal their dual importance in plant development and stress tolerance. Genome-wide sequence survey identified 20 non-redundant small heat shock proteins (sHsp) and 22 heat shock factor (Hsf) genes in barley. While all three major classes (A, B, C) of Hsfs are localized in nucleus, the 20 sHsp gene family members are localized in different cell organelles like cytoplasm, mitochondria, plastid and peroxisomes. Hsf and sHsp members are differentially regulated during drought and at different seed developmental stages suggesting the importance of chaperone role under drought as well as seed development. In silico cis-regulatory motif analysis of Hsf promoters showed an enrichment with abscisic acid responsive cis-elements (ABRE), implying regulatory role of ABA in mediating transcriptional response of HvsHsf genes. Gene regulatory network analysis identified HvHsfB2c as potential central regulator of the seed-specific expression of several HvsHsps including 17.5CI sHsp. These results indicate that HvHsfB2c is co-expressed in the central hub of small Hsps and therefore it may be regulating the expression of several HvsHsp subclasses HvHsp16.88-CI, HvHsp17.5-CI and HvHsp17.7-CI. The in vivo relevance of binding specificity of HvHsfB2C transcription factor to HSE-element present in the promoter of HvSHP17.5-CI under heat stress exposure is confirmed by gel shift and LUC-reporter assays. Further, we isolated 477 bp cDNA from barley encoding a 17.5 sHsp polypeptide, which was predominantly upregulated under drought stress treatments and also preferentially expressed in developing seeds. Recombinant HvsHsp17.5-CI protein was expressed in E. coli and purified to homogeneity, which displayed in vitro chaperone activity. The predicted structural model of HvsHsp-17.5-CI protein suggests that the α-crystallin domain is evolutionarily highly

Barcoding heat shock proteins to human diseases: looking beyond the heat shock response.

PubMed

Kakkar, Vaishali; Meister-Broekema, Melanie; Minoia, Melania; Carra, Serena; Kampinga, Harm H

2014-04-01

There are numerous human diseases that are associated with protein misfolding and the formation of toxic protein aggregates. Activating the heat shock response (HSR)--and thus generally restoring the disturbed protein homeostasis associated with such diseases--has often been suggested as a therapeutic strategy. However, most data on activating the HSR or its downstream targets in mouse models of diseases associated with aggregate formation have been rather disappointing. The human chaperonome consists of many more heat shock proteins (HSPs) that are not regulated by the HSR, however, and researchers are now focusing on these as potential therapeutic targets. In this Review, we summarize the existing literature on a set of aggregation diseases and propose that each of them can be characterized or 'barcoded' by a different set of HSPs that can rescue specific types of aggregation. Some of these 'non-canonical' HSPs have demonstrated effectiveness in vivo, in mouse models of protein-aggregation disease. Interestingly, several of these HSPs also cause diseases when mutated--so-called chaperonopathies--which are also discussed in this Review.

Barcoding heat shock proteins to human diseases: looking beyond the heat shock response

PubMed Central

Kakkar, Vaishali; Meister-Broekema, Melanie; Minoia, Melania; Carra, Serena; Kampinga, Harm H.

2014-01-01

There are numerous human diseases that are associated with protein misfolding and the formation of toxic protein aggregates. Activating the heat shock response (HSR) – and thus generally restoring the disturbed protein homeostasis associated with such diseases – has often been suggested as a therapeutic strategy. However, most data on activating the HSR or its downstream targets in mouse models of diseases associated with aggregate formation have been rather disappointing. The human chaperonome consists of many more heat shock proteins (HSPs) that are not regulated by the HSR, however, and researchers are now focusing on these as potential therapeutic targets. In this Review, we summarize the existing literature on a set of aggregation diseases and propose that each of them can be characterized or ‘barcoded’ by a different set of HSPs that can rescue specific types of aggregation. Some of these ‘non-canonical’ HSPs have demonstrated effectiveness in vivo, in mouse models of protein-aggregation disease. Interestingly, several of these HSPs also cause diseases when mutated – so-called chaperonopathies – which are also discussed in this Review. PMID:24719117

Electron Heating in Low-Mach-number Perpendicular Shocks. I. Heating Mechanism

NASA Astrophysics Data System (ADS)

Guo, Xinyi; Sironi, Lorenzo; Narayan, Ramesh

2017-12-01

Recent X-ray observations of merger shocks in galaxy clusters have shown that the postshock plasma has two temperatures, with the protons hotter than the electrons. By means of two-dimensional particle-in-cell simulations, we study the physics of electron irreversible heating in low-Mach-number perpendicular shocks, for a representative case with sonic Mach number of 3 and plasma beta of 16. We find that two basic ingredients are needed for electron entropy production: (1) an electron temperature anisotropy, induced by field amplification coupled to adiabatic invariance; and (2) a mechanism to break the electron adiabatic invariance itself. In shocks, field amplification occurs at two major sites: at the shock ramp, where density compression leads to an increase of the frozen-in field; and farther downstream, where the shock-driven proton temperature anisotropy generates strong proton cyclotron and mirror modes. The electron temperature anisotropy induced by field amplification exceeds the threshold of the electron whistler instability. The growth of whistler waves breaks the electron adiabatic invariance and allows for efficient entropy production. For our reference run, the postshock electron temperature exceeds the adiabatic expectation by ≃ 15 % , resulting in an electron-to-proton temperature ratio of ≃ 0.45. We find that the electron heating efficiency displays only a weak dependence on mass ratio (less than ≃ 30 % drop, as we increase the mass ratio from {m}i/{m}e=49 up to {m}i/{m}e=1600). We develop an analytical model of electron irreversible heating and show that it is in excellent agreement with our simulation results.

Atypical Particle Heating at a Supercritical Interplanetary Shock

NASA Technical Reports Server (NTRS)

Wilson, Lynn B., III

2010-01-01

We present the first observations at an interplanetary shock of large amplitude (> 100 mV/m pk-pk) solitary waves and large amplitude (approx.30 mV/m pk-pk) waves exhibiting characteristics consistent with electron Bernstein waves. The Bernstein-like waves show enhanced power at integer and half-integer harmonics of the cyclotron frequency with a broadened power spectrum at higher frequencies, consistent with the electron cyclotron drift instability. The Bernstein-like waves are obliquely polarized with respect to the magnetic field but parallel to the shock normal direction. Strong particle heating is observed in both the electrons and ions. The observed heating and waveforms are likely due to instabilities driven by the free energy provided by reflected ions at this supercritical interplanetary shock. These results offer new insights into collisionless shock dissipation and wave-particle interactions in the solar wind.

Shuttle ascent and shock impingement aerodynamic heating studies

NASA Technical Reports Server (NTRS)

Lanning, W. D.; Hung, F. T.

1971-01-01

The collection and analysis of aerodynamic heating data obtained from shock impingement experimental investigation were completed. The data were categorized into four interference areas; fin leading edge, wing/fuselage fin/plate corners, and space shuttle configurations. The effects of shock impingement were found to increase the heating rates 10 to 40 times the undisturbed values. A test program was completed at NASA/Langley Research Center to investigate the magnitudes and surface patterns of the mated shock interference flowfield. A 0.0065 scale thin-skin model of the MDAC 256-20 space shuttle booster mated with a Stycast model of the MDAC Internal tank orbiter was tested in the 20-inch M=6 tunnel, the 31-inch M=10 tunnel, and the 48-inch Unitary Plan Tunnel. The gap region of the ascent configuration was the principal area of interest where both thermocouple and phase-change paint data were obtained. Pressure and heat transfer distributions data on the leeward surface of a 75-degree sweep slab delta wing are presented. The effects of surface roughness on boundary layer transition and aerodynamic heating were investigated.

Wheat Chloroplast Targeted sHSP26 Promoter Confers Heat and Abiotic Stress Inducible Expression in Transgenic Arabidopsis Plants

PubMed Central

Khurana, Neetika; Chauhan, Harsh; Khurana, Paramjit

2013-01-01

The small heat shock proteins (sHSPs) have been found to play a critical role in physiological stress conditions in protecting proteins from irreversible aggregation. To characterize the hloroplast targeted sHSP26 promoter in detail, deletion analysis of the promoter is carried out and analysed via transgenics in Arabidopsis. In the present study, complete assessment of the importance of CCAAT-box elements along with Heat shock elements (HSEs) in the promoter of sHSP26 was performed. Moreover, the importance of 5′ untranslated region (UTR) has also been established in the promoter via Arabidopsis transgenics. An intense GUS expression was observed after heat stress in the transgenics harbouring a full-length promoter, confirming the heat-stress inducibility of the promoter. Transgenic plants without UTR showed reduced GUS expression when compared to transgenic plants with UTR as was confirmed at the RNA and protein levels by qRT-PCR and GUS histochemical assays, thus suggesting the possible involvement of some regulatory elements present in the UTR in heat-stress inducibility of the promoter. Promoter activity was also checked under different abiotic stresses and revealed differential expression in different deletion constructs. Promoter analysis based on histochemical assay, real-time qPCR and fluorimetric analysis revealed that HSEs alone could not transcribe GUS gene significantly in sHSP26 promoter and CCAAT box elements contribute synergistically to the transcription. Our results also provide insight into the importance of 5`UTR of sHsp26 promoter thus emphasizing the probable role of imperfect CCAAT-box element or some novel cis-element with respect to heat stress. PMID:23349883

Regulation of the mammalian heat shock factor 1.

PubMed

Dayalan Naidu, Sharadha; Dinkova-Kostova, Albena T

2017-06-01

Living organisms are endowed with the capability to tackle various forms of cellular stress due to the presence of molecular chaperone machinery complexes that are ubiquitous throughout the cell. During conditions of proteotoxic stress, the transcription factor heat shock factor 1 (HSF1) mediates the elevation of heat shock proteins, which are crucial components of the chaperone complex machinery and function to ameliorate protein misfolding and aggregation and restore protein homeostasis. In addition, HSF1 orchestrates a versatile transcriptional programme that includes genes involved in repair and clearance of damaged macromolecules and maintenance of cell structure and metabolism, and provides protection against a broad range of cellular stress mediators, beyond heat shock. Here, we discuss the structure and function of the mammalian HSF1 and its regulation by post-translational modifications (phosphorylation, sumoylation and acetylation), proteasomal degradation, and small-molecule activators and inhibitors. © 2017 Federation of European Biochemical Societies.

Expression of the Caulobacter heat shock gene dnaK is developmentally controlled during growth at normal temperatures.

PubMed Central

Gomes, S L; Gober, J W; Shapiro, L

1990-01-01

Caulobacter crescentus has a single dnaK gene that is highly homologous to the hsp70 family of heat shock genes. Analysis of the cloned and sequenced dnaK gene has shown that the deduced amino acid sequence could encode a protein of 67.6 kilodaltons that is 68% identical to the DnaK protein of Escherichia coli and 49% identical to the Drosophila and human hsp70 protein family. A partial open reading frame 165 base pairs 3' to the end of dnaK encodes a peptide of 190 amino acids that is 59% identical to DnaJ of E. coli. Northern blot analysis revealed a single 4.0-kilobase mRNA homologous to the cloned fragment. Since the dnaK coding region is 1.89 kilobases, dnaK and dnaJ may be transcribed as a polycistronic message. S1 mapping and primer extension experiments showed that transcription initiated at two sites 5' to the dnaK coding sequence. A single start site of transcription was identified during heat shock at 42 degrees C, and the predicted promoter sequence conformed to the consensus heat shock promoters of E. coli. At normal growth temperature (30 degrees C), a different start site was identified 3' to the heat shock start site that conformed to the E. coli sigma 70 promoter consensus sequence. S1 protection assays and analysis of expression of the dnaK gene fused to the lux transcription reporter gene showed that expression of dnaK is temporally controlled under normal physiological conditions and that transcription occurs just before the initiation of DNA replication. Thus, in both human cells (I. K. L. Milarski and R. I. Morimoto, Proc. Natl. Acad. Sci. USA 83:9517-9521, 1986) and in a simple bacterium, the transcription of a hsp70 gene is temporally controlled as a function of the cell cycle under normal growth conditions. Images PMID:2345134

Cognitive Function and Heat Shock Protein 70 in Children With Temporal Lobe Epilepsy.

PubMed

Oraby, Azza M; Raouf, Ehab R Abdol; El-Saied, Mostafa M; Abou-Khadra, Maha K; Helal, Suzette I; Hashish, Adel F

2017-01-01

We conducted the present study to examine cognitive function and serum heat shock protein 70 levels among children with temporal lobe epilepsy. The Stanford-Binet Intelligence Test was carried out to examine cognitive function in 30 children with temporal lobe epilepsy and 30 controls. Serum heat shock protein 70 levels were determined with an enzyme-linked immunosorbent assay. The epilepsy group had significantly lower cognitive function testing scores and significantly higher serum heat shock protein 70 levels than the control group; there were significant negative correlations between serum heat shock protein 70 levels and short-term memory and composite scores. Children with uncontrolled seizures had significantly lower verbal reasoning scores and significantly higher serum heat shock protein 70 levels than children with controlled seizures. Children with temporal lobe epilepsy have cognitive dysfunction and elevated levels of serum heat shock protein 70, which may be considered a stress biomarker.

Structure of genes for Hsp30 from the white-rot fungus Coriolus versicolor and the increase of their expression by heat shock and exposure to a hazardous chemical.

PubMed

Iimura, Yosuke; Tatsumi, Kenji

2002-07-01

We isolated and analysed two genomic DNAs that encode the heat-shock protein Hsp30 from Coriolus versicolor. The amino acid sequences substitute only three amino acid substitutions. The promoter regions contain the consensus heat-shock element, a xenobiotic-response element, a stress-response element, and a metal-response element. The levels of mRNAs for Hsp30 increased markedly after exposure of C. versicolor to pentachlorophenol and levels were higher than those after heat shock.

Heat-flow equation motivated by the ideal-gas shock wave.

PubMed

Holian, Brad Lee; Mareschal, Michel

2010-08-01

We present an equation for the heat-flux vector that goes beyond Fourier's Law of heat conduction, in order to model shockwave propagation in gases. Our approach is motivated by the observation of a disequilibrium among the three components of temperature, namely, the difference between the temperature component in the direction of a planar shock wave, versus those in the transverse directions. This difference is most prominent near the shock front. We test our heat-flow equation for the case of strong shock waves in the ideal gas, which has been studied in the past and compared to Navier-Stokes solutions. The new heat-flow treatment improves the agreement with nonequilibrium molecular-dynamics simulations of hard spheres under strong shockwave conditions.

TG2 regulates the heat-shock response by the post-translational modification of HSF1.

PubMed

Rossin, Federica; Villella, Valeria Rachela; D'Eletto, Manuela; Farrace, Maria Grazia; Esposito, Speranza; Ferrari, Eleonora; Monzani, Romina; Occhigrossi, Luca; Pagliarini, Vittoria; Sette, Claudio; Cozza, Giorgio; Barlev, Nikolai A; Falasca, Laura; Fimia, Gian Maria; Kroemer, Guido; Raia, Valeria; Maiuri, Luigi; Piacentini, Mauro

2018-05-11

Heat-shock factor 1 (HSF1) is the master transcription factor that regulates the response to proteotoxic stress by controlling the transcription of many stress-responsive genes including the heat-shock proteins. Here, we show a novel molecular mechanism controlling the activation of HSF1. We demonstrate that transglutaminase type 2 (TG2), dependent on its protein disulphide isomerase activity, triggers the trimerization and activation of HSF1 regulating adaptation to stress and proteostasis impairment. In particular, we find that TG2 loss of function correlates with a defect in the nuclear translocation of HSF1 and in its DNA-binding ability to the HSP70 promoter. We show that the inhibition of TG2 restores the unbalance in HSF1-HSP70 pathway in cystic fibrosis (CF), a human disorder characterized by deregulation of proteostasis. The absence of TG2 leads to an increase of about 40% in CFTR function in a new experimental CF mouse model lacking TG2. Altogether, these results indicate that TG2 plays a key role in the regulation of cellular proteostasis under stressful cellular conditions through the modulation of the heat-shock response. © 2018 The Authors.

The Stress Granule RNA-Binding Protein TIAR-1 Protects Female Germ Cells from Heat Shock in Caenorhabditis elegans.

PubMed

Huelgas-Morales, Gabriela; Silva-García, Carlos Giovanni; Salinas, Laura S; Greenstein, David; Navarro, Rosa E

2016-04-07

In response to stressful conditions, eukaryotic cells launch an arsenal of regulatory programs to protect the proteome. One major protective response involves the arrest of protein translation and the formation of stress granules, cytoplasmic ribonucleoprotein complexes containing the conserved RNA-binding proteins TIA-1 and TIAR. The stress granule response is thought to preserve mRNA for translation when conditions improve. For cells of the germline-the immortal cell lineage required for sexual reproduction-protection from stress is critically important for perpetuation of the species, yet how stress granule regulatory mechanisms are deployed in animal reproduction is incompletely understood. Here, we show that the stress granule protein TIAR-1 protects the Caenorhabditis elegans germline from the adverse effects of heat shock. Animals containing strong loss-of-function mutations in tiar-1 exhibit significantly reduced fertility compared to the wild type following heat shock. Analysis of a heat-shock protein promoter indicates that tiar-1 mutants display an impaired heat-shock response. We observed that TIAR-1 was associated with granules in the gonad core and oocytes during several stressful conditions. Both gonad core and oocyte granules are dynamic structures that depend on translation; protein synthesis inhibitors altered their formation. Nonetheless, tiar-1 was required for the formation of gonad core granules only. Interestingly, the gonad core granules did not seem to be needed for the germ cells to develop viable embryos after heat shock. This suggests that TIAR-1 is able to protect the germline from heat stress independently of these structures. Copyright © 2016 Huelgas-Morales et al.

The Stress Granule RNA-Binding Protein TIAR-1 Protects Female Germ Cells from Heat Shock in Caenorhabditis elegans

PubMed Central

Huelgas-Morales, Gabriela; Silva-García, Carlos Giovanni; Salinas, Laura S.; Greenstein, David; Navarro, Rosa E.

2016-01-01

In response to stressful conditions, eukaryotic cells launch an arsenal of regulatory programs to protect the proteome. One major protective response involves the arrest of protein translation and the formation of stress granules, cytoplasmic ribonucleoprotein complexes containing the conserved RNA-binding proteins TIA-1 and TIAR. The stress granule response is thought to preserve mRNA for translation when conditions improve. For cells of the germline—the immortal cell lineage required for sexual reproduction—protection from stress is critically important for perpetuation of the species, yet how stress granule regulatory mechanisms are deployed in animal reproduction is incompletely understood. Here, we show that the stress granule protein TIAR-1 protects the Caenorhabditis elegans germline from the adverse effects of heat shock. Animals containing strong loss-of-function mutations in tiar-1 exhibit significantly reduced fertility compared to the wild type following heat shock. Analysis of a heat-shock protein promoter indicates that tiar-1 mutants display an impaired heat-shock response. We observed that TIAR-1 was associated with granules in the gonad core and oocytes during several stressful conditions. Both gonad core and oocyte granules are dynamic structures that depend on translation; protein synthesis inhibitors altered their formation. Nonetheless, tiar-1 was required for the formation of gonad core granules only. Interestingly, the gonad core granules did not seem to be needed for the germ cells to develop viable embryos after heat shock. This suggests that TIAR-1 is able to protect the germline from heat stress independently of these structures. PMID:26865701

Transfection and heat-inducible expression of molluscan promoter-luciferase reporter gene constructs in the Biomphalaria glabrata embryonic snail cell line.

PubMed

Yoshino, T P; Wu, X J; Liu, H D

1998-09-01

Studies were initiated to begin developing a genetic transformation system for cells derived from the freshwater gastropod, Biomphalaria glabrata, an intermediate host of the human blood fluke Schistosoma mansoni. Using a 70-kD heat-shock protein (HSP70) cDNA probe obtained from the B. glabrata embryonic (Bge) cell line, we cloned from Bge cells a complete HSP70 gene including a 1-kb genomic DNA fragment in its 5'-flanking region containing sequences indicative of a HSP promoter. Identified in the 5'-half (416 nucleotides) of this genomic fragment were TATA and CAAT boxes, two putative transcription initiation sites, and a series of palindromic DNA repeats with shared homology to the heat-shock element consensus sequence (Bge HSP70(0.5k) promoter). The 3'-half of this upstream flanking region was comprised of a 508-base intron located immediately 5' of the ATG start codon. To determine the functionality of the putative snail promoter sequence, Bge HSP promoter/luciferase (Luc) reporter gene constructs were introduced into Bge cells by N-(1-(2,3-dioleoyloxy) propyl)-N,N,N-trimethylammonium methylsulfate (DOTAP)-mediated transfection methods, and assayed for Luc activity 48 hr following a 1.5-hr heat-shock treatment (40 degrees C). Compared with control vectors or the Bge HSP70(0.5k/1.0k) promoter constructs at 26 degrees C, a 10- to 300-fold increase in Luc expression was obtained only in the Bge HSP70 promoter/Luc-transfected cells following heat-shock. Results of transfection experiments demonstrate that the Bge HSP70(0.5k) DNA segment contains appropriate promoter sequences for driving temperature-inducible gene expression in the Bge snail cell line. This report represents the first isolation and functional characterization of an inducible promoter from a freshwater gastropod mollusc. Successful transient expression of a foreign reporter gene in Bge cells using a homologous, inducible promoter sequence now paves the way for development of methods for stable

Ecotypic variation in chloroplast small heat-shock proteins and related thermotolerance in Chenopodium album.

PubMed

Shakeel, Samina; Haq, Noor Ul; Heckathorn, Scott A; Hamilton, E William; Luthe, Dawn S

2011-08-01

Production of chloroplast-localized small heat-shock proteins (Cp-sHSP) is correlated with increased thermotolerance in plants. Ecotypic variation in function and expression of Cp-sHSPs was analyzed in two Chenopodium album ecotypes from cool vs. warm-temperate USA habitats [New York (NY) and Mississippi (MS) respectively]. P(et) was more heat tolerant in the MS than the NY ecotype, and MS ecotype derived proportionally greater protection of P(et) by Cp-sHSP during high temperatures. Four genes encoding Cp-sHSPs were isolated and characterized: CaHSP25.99n (NY-1) and CaHSP26.23n (NY-2) from NY ecotype, and CaHSP26.04m (MS-1) and CaHSP26.26m (MS-2) from MS ecotype. The genes were nearly identical in predicted amino-acid sequence and hydrophobicity. Gene expression analysis indicated that MS-1 and MS-2 transcripts were constitutively expressed at low levels at 25 °C, while no NY-1 and NY-2 transcripts were detected at this temperature. Maximum accumulation of NY-1 and NY-2 transcripts occurred at 33 °C and 40 °C for MS-1 and MS-2. Immunoblot analysis revealed that (1) protein expression was highest at 37 °C in both ecotypes, but was greater in MS than NY ecotype at 40 °C; and (2) import of Cp-sHSP into chloroplasts was more heat-labile in NY ecotype. The higher expression of one isoform in MS ecotype may contribute to its enhanced thermotolerance. Absence of correlation between protein and transcript levels, suggests the post-transcriptional regulation is occurring. Promoter analysis of these genes revealed significant variations in heat-shock elements (HSE), core motifs required for heat-shock-factor binding. We propose a correlation between unique promoter architecture, Cp-sHSP expression and thermotolerance in both ecotypes. Published by Elsevier Masson SAS.

Microbial communities involved in biogas production exhibit high resilience to heat shocks.

PubMed

Abendroth, Christian; Hahnke, Sarah; Simeonov, Claudia; Klocke, Michael; Casani-Miravalls, Sonia; Ramm, Patrice; Bürger, Christoph; Luschnig, Olaf; Porcar, Manuel

2018-02-01

We report here the impact of heat-shock treatments (55 and 70 °C) on the biogas production within the acidification stage of a two-stage reactor system for anaerobic digestion and biomethanation of grass. The microbiome proved both taxonomically and functionally very robust, since heat shocks caused minor community shifts compared to the controls, and biogas yield was not decreased. The strongest impact on the microbial profile was observed with a combination of heat shock and low pH. Since no transient reduction of microbial diversity occured after the shock, biogas keyplayers, but also potential pathogens, survived the treatment. All along the experiment, the heat-resistant bacterial profile consisted mainly of Firmicutes, Bacteroidetes and Proteobacteria. Bacteroides and Acholeplasma were reduced after heat shocks. An increase was observed for Aminobacterium. Our results prove the stability to thermal stresses of the microbial communities involved in acidification, and the resilience in biogas production irrespectively of the thermal treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Small Heat Shock Proteins in Redox Metabolism: Implications for Cardiovascular Diseases

PubMed Central

Christians, Elisabeth S.; Ishiwata, Takahiro; Benjamin, Ivor J.

2012-01-01

A timely review series on small heat shock proteins has to appropriately examine their fundamental properties and implications in the cardiovascular system since several members of this chaperone family exhibit robust expression in the myocardium and blood vessels. Due to energetic and metabolic demands, the cardiovascular system maintains a high mitochondrial activity but irreversible oxidative damage might ensue from increased production of reactive oxygen species. How equilibrium between their production and scavenging is achieved becomes paramount for physiological maintenance. For example, heat shock protein B1 (HSPB1) is implicated in maintaining this equilibrium or redox homeostasis by upholding the level of glutathione, a major redox mediator. Studies of gain or loss of function achieved by genetic manipulations have been highly informative for understanding the roles of those proteins. For example, genetic deficiency of several small heat shock proteins such as HSPB5 and HSPB2 is well-tolerated in heart cells whereas a single missense mutation causes human pathology. Such evidence highlights both the profound genetic redundancy observed among the multigene family of small heat shock proteins while underscoring the role proteotoxicity plays in driving disease pathogenesis. We will discuss the available data on small heat shock proteins in the cardiovascular system, redox metabolism and human diseases. From the medical perspective, we envision that such emerging knowledge of the multiple roles small heat shock proteins exert in the cardiovascular system will undoubtedly open new avenues for their identification and possible therapeutic targeting in humans. PMID:22710345

Heat Shock Factor 1 Epigenetically Stimulates Glutaminase-1-Dependent mTOR Activation to Promote Colorectal Carcinogenesis.

PubMed

Li, Jiaqiu; Song, Ping; Jiang, Tingting; Dai, Dongjun; Wang, Hanying; Sun, Jie; Zhu, Liyuan; Xu, Wenxia; Feng, Lifeng; Shin, Vivian Y; Morrison, Helen; Wang, Xian; Jin, Hongchuan

2018-04-14

Heat shock factor 1 (HSF1) generally exhibits its properties under stress conditions. In tumors, HSF1 has a pleiotropic feature in regulating growth, survival, and aggressiveness of cancer cells. In this study, we found HSF1 was increased in colorectal cancer (CRC) and had a positive correlation with shorter disease-free survival (DFS). Knockdown of HSF1 in CRC cells attenuated their growth while inhibiting mTOR activation and glutamine metabolism. HSF1 inhibited the expression of microRNA137 (MIR137), which targeted GLS1 (glutaminase 1), thus stimulating GLS1 protein expression to promote glutaminolysis and mTOR activation. HSF1 bound DNA methyltransferase DNMT3a and recruited it to the promoter of lncRNA MIR137 host gene (MIR137HG), suppressing the generation of primary MIR137. The chemical inhibitor of HSF1 also reduced cell growth, increased apoptosis, and impaired glutamine metabolism in vitro. Moreover, both chemical inhibition and genetic knockout of HSF1 succeeded in increasing MIR137 expression, reducing GLS1 expression, and alleviating colorectal tumorigenesis in azoxymethane (AOM)/dextran sulfate sodium (DSS) mice. In conclusion, HSF1 expression was increased and associated with poor prognosis in CRC. By recruiting DNMT3a to suppress the expression of MIR137 that targets GLS1 mRNA, HSF1 stimulated GLS1-dependent mTOR activation to promote colorectal carcinogenesis. Therefore, targeting HSF1 to attenuate glutaminolysis and mTOR activation could be a promising approach for CRC treatment. Copyright © 2018 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Expression of cholesteryl glucoside by heat shock in human fibroblasts

PubMed Central

Kunimoto, Shohko; Kobayashi, Tetsuyuki; Kobayashi, Susumu; Murakami-Murofushi, Kimiko

2000-01-01

ABSTRACT We investigated the heat-induced alteration of glycolipids in human cultured cells, TIG-3 fibroblasts, to show the expression of steryl glucoside by heat shock. A glycolipid band was detected on a thin-layer chromatography plate in lipid extracts from TIG-3 cells exposed to high temperature (42°C) for 15 and 30 minutes, while it was hardly detectable without heat shock. Both cholesterol and glucose were almost exclusively detected by gas liquid chromatography as degradation products of the lipid. The structure of the lipid molecule was elucidated by electrospray mass spectrometry to be a cholesteryl glucoside. This is the first report to show the occurrence of a steryl glucoside in mammalian cells, and this substance is considered to have a significant role in heat shock responses in mammalian cells. PMID:10701833

Dynamic m(6)A mRNA methylation directs translational control of heat shock response.

PubMed

Zhou, Jun; Wan, Ji; Gao, Xiangwei; Zhang, Xingqian; Jaffrey, Samie R; Qian, Shu-Bing

2015-10-22

The most abundant mRNA post-transcriptional modification is N(6)-methyladenosine (m(6)A), which has broad roles in RNA biology. In mammalian cells, the asymmetric distribution of m(6)A along mRNAs results in relatively less methylation in the 5' untranslated region (5'UTR) compared to other regions. However, whether and how 5'UTR methylation is regulated is poorly understood. Despite the crucial role of the 5'UTR in translation initiation, very little is known about whether m(6)A modification influences mRNA translation. Here we show that in response to heat shock stress, certain adenosines within the 5'UTR of newly transcribed mRNAs are preferentially methylated. We find that the dynamic 5'UTR methylation is a result of stress-induced nuclear localization of YTHDF2, a well-characterized m(6)A 'reader'. Upon heat shock stress, the nuclear YTHDF2 preserves 5'UTR methylation of stress-induced transcripts by limiting the m(6)A 'eraser' FTO from demethylation. Remarkably, the increased 5'UTR methylation in the form of m(6)A promotes cap-independent translation initiation, providing a mechanism for selective mRNA translation under heat shock stress. Using Hsp70 mRNA as an example, we demonstrate that a single m(6)A modification site in the 5'UTR enables translation initiation independent of the 5' end N(7)-methylguanosine cap. The elucidation of the dynamic features of 5'UTR methylation and its critical role in cap-independent translation not only expands the breadth of physiological roles of m(6)A, but also uncovers a previously unappreciated translational control mechanism in heat shock response.

Chromosome behavior of heat shock induced triploid in Fenneropenaeus chinensis

NASA Astrophysics Data System (ADS)

Zhang, Xiaojun; Li, Fuhua; Xiang, Jianhai

2003-09-01

Triploidy was induced in Chinese shrimp Fenneropenaeus chinensis by 30±0.5°C heat shock treatment (initiated at 20 min after fertilization) for 10 min to inhibit the release of PB2 at 18.0°C. The highest triploid rate obtained was 84.5% in nauplius stage. The effect of heat shock treatment on meiosis and cleavage of eggs was investigated in this work aimed to establish efficient procedures for triploid induction and to gain understanding of the mechanism of triploid production. Three pronuclei that could be observed in the treated eggs under fluorescence microscope developed into triploid embryos. Some abnormal chromosome behavior was observed in heat shocked eggs.

Heat Shock Proteins in Association with Heat Tolerance in Grasses

PubMed Central

Xu, Yan; Zhan, Chenyang; Huang, Bingru

2011-01-01

The grass family Poaceae includes annual species cultivated as major grain crops and perennial species cultivated as forage or turf grasses. Heat stress is a primary factor limiting growth and productivity of cool-season grass species and is becoming a more significant problem in the context of global warming. Plants have developed various mechanisms in heat-stress adaptation, including changes in protein metabolism such as the induction of heat shock proteins (HSPs). This paper summarizes the structure and function of major HSPs, recent research progress on the association of HSPs with grass tolerance to heat stress, and incorporation of HSPs in heat-tolerant grass breeding. PMID:22084689

Heat Shock Protein Augmentation of Angelica gigas Nakai Root Hot Water Extract on Adipogenic Differentiation in Murine 3T3-L1 Preadipocytes

PubMed Central

Lumbera, Wenchie Marie L.; dela Cruz, Joseph; Yang, Seung-Hak; Hwang, Seong Gu

2016-01-01

There is a high association of heat shock on the alteration of energy and lipid metabolism. The alterations associated with thermal stress are composed of gene expression changes and adaptation through biochemical responses. Previous study showed that Angelica gigas Nakai (AGN) root extract promoted adipogenic differentiation in murine 3T3-L1 preadipocytes under the normal temperature condition. However, its effect in heat shocked 3T3-L1 cells has not been established. In this study, we investigated the effect of AGN root hot water extract in the adipogenic differentiation of murine 3T3-L1 preadipocytes following heat shock and its possible mechanism of action. Thermal stress procedure was executed within the same stage of preadipocyte confluence (G0) through incubation at 42°C for one hour and then allowed to recover at normal incubation temperature of 37°C for another hour before AGN treatment for both cell viability assay and Oil Red O. Cell viability assay showed that AGN was able to dose dependently (0 to 400 μg/mL) increase cell proliferation under normal incubation temperature and also was able to prevent cytotoxicity due to heat shock accompanied by cell proliferation. Confluent preadipocytes were subjected into heat shock procedure, recovery and then AGN treatment prior to stimulation with the differentiation solution. Heat shocked preadipocytes exhibited reduced differentiation as supported by decreased amount of lipid accumulation in Oil Red O staining and triglyceride measurement. However, those heat shocked preadipocytes that then were given AGN extract showed a dose dependent increase in lipid accumulation as shown by both evaluation procedures. In line with these results, real-time polymerase chain reaction (RT-PCR) and Western blot analysis showed that AGN increased adipogenic differentiation by upregulating heat shock protection related genes and proteins together with the adipogenic markers. These findings imply the potential of AGN in heat

Heat Shock Protein Augmentation of Angelica gigas Nakai Root Hot Water Extract on Adipogenic Differentiation in Murine 3T3-L1 Preadipocytes.

PubMed

Lumbera, Wenchie Marie L; Dela Cruz, Joseph; Yang, Seung-Hak; Hwang, Seong Gu

2016-03-01

There is a high association of heat shock on the alteration of energy and lipid metabolism. The alterations associated with thermal stress are composed of gene expression changes and adaptation through biochemical responses. Previous study showed that Angelica gigas Nakai (AGN) root extract promoted adipogenic differentiation in murine 3T3-L1 preadipocytes under the normal temperature condition. However, its effect in heat shocked 3T3-L1 cells has not been established. In this study, we investigated the effect of AGN root hot water extract in the adipogenic differentiation of murine 3T3-L1 preadipocytes following heat shock and its possible mechanism of action. Thermal stress procedure was executed within the same stage of preadipocyte confluence (G0) through incubation at 42°C for one hour and then allowed to recover at normal incubation temperature of 37°C for another hour before AGN treatment for both cell viability assay and Oil Red O. Cell viability assay showed that AGN was able to dose dependently (0 to 400 μg/mL) increase cell proliferation under normal incubation temperature and also was able to prevent cytotoxicity due to heat shock accompanied by cell proliferation. Confluent preadipocytes were subjected into heat shock procedure, recovery and then AGN treatment prior to stimulation with the differentiation solution. Heat shocked preadipocytes exhibited reduced differentiation as supported by decreased amount of lipid accumulation in Oil Red O staining and triglyceride measurement. However, those heat shocked preadipocytes that then were given AGN extract showed a dose dependent increase in lipid accumulation as shown by both evaluation procedures. In line with these results, real-time polymerase chain reaction (RT-PCR) and Western blot analysis showed that AGN increased adipogenic differentiation by upregulating heat shock protection related genes and proteins together with the adipogenic markers. These findings imply the potential of AGN in heat

Synergistic induction of the heat shock response in Escherichia coli by simultaneous treatment with chemical inducers.

PubMed Central

Van Dyk, T K; Reed, T R; Vollmer, A C; LaRossa, R A

1995-01-01

Escherichia coli strains carrying transcriptional fusions of four sigma 32-controlled E. coli heat shock promoters to luxCDABE or lacZ reporter genes were stressed by chemicals added singly or in pairs. Much more than additive induction resulted from combinations of cadmium chloride, copper sulfate, ethanol, formamide, 4-nitrophenol, and pentachlorophenol. PMID:7592357

Conditions for shock revival by neutrino heating in core-collapse supernovae

NASA Astrophysics Data System (ADS)

Janka, H.-Th.

2001-03-01

Energy deposition by neutrinos can rejuvenate the stalled bounce shock and can provide the energy for the supernova explosion of a massive star. This neutrino-heating mechanism, though investigated by numerical simulations and analytic studies, is not finally accepted or proven as the trigger of the explosion. Part of the problem is that different groups have obtained seemingly discrepant results, and the complexity of the hydrodynamic models often hampers a clear and simple interpretation of the results. This demands a deeper theoretical understanding of the requirements of a successful shock revival. A toy model is developed here for discussing the neutrino heating phase analytically. The neutron star atmosphere between the neutrinosphere and the supernova shock can well be considered to be in hydrostatic equilibrium, with a layer of net neutrino cooling below the gain radius and a layer of net neutrino heating above. Since the mass infall rate to the shock is in general different from the rate at which gas is advected into the neutron star, the mass in the gain layer varies with time. Moreover, the gain layer receives additional energy input by neutrinos emitted from the neutrinosphere and the cooling layer. Therefore the determination of the shock evolution requires a time-dependent treatment. To this end the hydrodynamical equations of continuity and energy are integrated over the volume of the gain layer to obtain conservation laws for the total mass and energy in this layer. The radius and velocity of the supernova shock can then be calculated from global properties of the gain layer as solutions of an initial value problem, which expresses the fact that the behavior of the shock is controlled by the cumulative effects of neutrino heating and mass accumulation in the gain layer. The described toy model produces steady-state accretion and mass outflow from the nascent neutron star as special cases. The approach is useful to illuminate the conditions that can

Synergistic Effects of Toxic Elements on Heat Shock Proteins

PubMed Central

Mahmood, Khalid; Mahmood, Qaisar; Irshad, Muhammad; Hussain, Jamshaid

2014-01-01

Heat shock proteins show remarkable variations in their expression levels under a variety of toxic conditions. A research span expanded over five decades has revealed their molecular characterization, gene regulation, expression patterns, vast similarity in diverse groups, and broad range of functional capabilities. Their functions include protection and tolerance against cytotoxic conditions through their molecular chaperoning activity, maintaining cytoskeleton stability, and assisting in cell signaling. However, their role as biomarkers for monitoring the environmental risk assessment is controversial due to a number of conflicting, validating, and nonvalidating reports. The current knowledge regarding the interpretation of HSPs expression levels has been discussed in the present review. The candidature of heat shock proteins as biomarkers of toxicity is thus far unreliable due to synergistic effects of toxicants and other environmental factors. The adoption of heat shock proteins as “suit of biomarkers in a set of organisms” requires further investigation. PMID:25136596

Differential expression of heat shock transcription factors and heat shock proteins after acute and chronic heat stress in laying chickens (Gallus gallus).

PubMed

Xie, Jingjing; Tang, Li; Lu, Lin; Zhang, Liyang; Xi, Lin; Liu, Hsiao-Ching; Odle, Jack; Luo, Xugang

2014-01-01

Heat stress due to high environmental temperature negatively influences animal performances. To better understand the biological impact of heat stress, laying broiler breeder chickens were subjected either to acute (step-wisely increasing temperature from 21 to 35°C within 24 hours) or chronic (32°C for 8 weeks) high temperature exposure. High temperature challenges significantly elevated body temperature of experimental birds (P<0.05). However, oxidation status of lipid and protein and expression of heat shock transcription factors (HSFs) and heat shock proteins (HSPs) 70 and 90 were differently affected by acute and chronic treatment. Tissue-specific responses to thermal challenge were also found among heart, liver and muscle. In the heart, acute heat challenge affected lipid oxidation (P = 0.05) and gene expression of all 4 HSF gene expression was upregulated (P<0.05). During chronic heat treatment, the HSP 70 mRNA level was increased (P<0.05) and HSP 90 mRNA (P<0.05) was decreased. In the liver, oxidation of protein was alleviated during acute heat challenge (P<0.05), however, gene expression HSF2, 3 and 4 and HSP 70 were highly induced (P<0.05). HSP90 expression was increased by chronic thermal treatment (P<0.05). In the muscle, both types of heat stress increased protein oxidation, but HSFs and HSPs gene expression remained unaltered. Only tendencies to increase were observed in HSP 70 (P = 0.052) and 90 (P = 0.054) gene expression after acute heat stress. The differential expressions of HSF and HSP genes in different tissues of laying broiler breeder chickens suggested that anti-heat stress mechanisms might be provoked more profoundly in the heart, by which the muscle was least protected during heat stress. In addition to HSP, HSFs gene expression could be used as a marker during acute heat stress.

Post-Transcriptional Regulation of the Trypanosome Heat Shock Response by a Zinc Finger Protein

PubMed Central

Droll, Dorothea; Minia, Igor; Fadda, Abeer; Singh, Aditi; Stewart, Mhairi; Queiroz, Rafael; Clayton, Christine

2013-01-01

In most organisms, the heat-shock response involves increased heat-shock gene transcription. In Kinetoplastid protists, however, virtually all control of gene expression is post-transcriptional. Correspondingly, Trypanosoma brucei heat-shock protein 70 (HSP70) synthesis after heat shock depends on regulation of HSP70 mRNA turnover. We here show that the T. brucei CCCH zinc finger protein ZC3H11 is a post-transcriptional regulator of trypanosome chaperone mRNAs. ZC3H11 is essential in bloodstream-form trypanosomes and for recovery of insect-form trypanosomes from heat shock. ZC3H11 binds to mRNAs encoding heat-shock protein homologues, with clear specificity for the subset of trypanosome chaperones that is required for protein refolding. In procyclic forms, ZC3H11 was required for stabilisation of target chaperone-encoding mRNAs after heat shock, and the HSP70 mRNA was also decreased upon ZC3H11 depletion in bloodstream forms. Many mRNAs bound to ZC3H11 have a consensus AUU repeat motif in the 3′-untranslated region. ZC3H11 bound preferentially to AUU repeats in vitro, and ZC3H11 regulation of HSP70 mRNA in bloodstream forms depended on its AUU repeat region. Tethering of ZC3H11 to a reporter mRNA increased reporter expression, showing that it is capable of actively stabilizing an mRNA. These results show that expression of trypanosome heat-shock genes is controlled by a specific RNA-protein interaction. They also show that heat-shock-induced chaperone expression in procyclic trypanosome enhances parasite survival at elevated temperatures. PMID:23592996

Post-Shock Sampling of Shock-Heated Hydrocarbon Fuels

DTIC Science & Technology

2016-07-07

on the ability to measure key hydrocarbon fragments (e.g. ethylene , methane, and acetylene) over a wide range of temperatures and pressures. The...series of experiments was conducted to validate the sampling system results and explore the thermal decomposition of ethylene and methane. Initially, a...1% ethylene /0.1% methane/balance argon fuel mixture was shock-heated to ~960 K – a temperature low enough that no reaction would occur. GC analysis

BAG3 Is a Modular, Scaffolding Protein that physically Links Heat Shock Protein 70 (Hsp70) to the Small Heat Shock Proteins.

PubMed

Rauch, Jennifer N; Tse, Eric; Freilich, Rebecca; Mok, Sue-Ann; Makley, Leah N; Southworth, Daniel R; Gestwicki, Jason E

2017-01-06

Small heat shock proteins (sHsps) are a family of ATP-independent molecular chaperones that are important for binding and stabilizing unfolded proteins. In this task, the sHsps have been proposed to coordinate with ATP-dependent chaperones, including heat shock protein 70 (Hsp70). However, it is not yet clear how these two important components of the chaperone network are linked. We report that the Hsp70 co-chaperone, BAG3, is a modular, scaffolding factor to bring together sHsps and Hsp70s. Using domain deletions and point mutations, we found that BAG3 uses both of its IPV motifs to interact with sHsps, including Hsp27 (HspB1), αB-crystallin (HspB5), Hsp22 (HspB8), and Hsp20 (HspB6). BAG3 does not appear to be a passive scaffolding factor; rather, its binding promoted de-oligomerization of Hsp27, likely by competing for the self-interactions that normally stabilize large oligomers. BAG3 bound to Hsp70 at the same time as Hsp22, Hsp27, or αB-crystallin, suggesting that it might physically bring the chaperone families together into a complex. Indeed, addition of BAG3 coordinated the ability of Hsp22 and Hsp70 to refold denatured luciferase in vitro. Together, these results suggest that BAG3 physically and functionally links Hsp70 and sHsps. Copyright © 2016 Elsevier Ltd. All rights reserved.

HSF1 and HSF3 cooperatively regulate the heat shock response in lizards.

PubMed

Takii, Ryosuke; Fujimoto, Mitsuaki; Matsuura, Yuki; Wu, Fangxu; Oshibe, Namiko; Takaki, Eiichi; Katiyar, Arpit; Akashi, Hiroshi; Makino, Takashi; Kawata, Masakado; Nakai, Akira

2017-01-01

Cells cope with temperature elevations, which cause protein misfolding, by expressing heat shock proteins (HSPs). This adaptive response is called the heat shock response (HSR), and it is regulated mainly by heat shock transcription factor (HSF). Among the four HSF family members in vertebrates, HSF1 is a master regulator of HSP expression during proteotoxic stress including heat shock in mammals, whereas HSF3 is required for the HSR in birds. To examine whether only one of the HSF family members possesses the potential to induce the HSR in vertebrate animals, we isolated cDNA clones encoding lizard and frog HSF genes. The reconstructed phylogenetic tree of vertebrate HSFs demonstrated that HSF3 in one species is unrelated with that in other species. We found that the DNA-binding activity of both HSF1 and HSF3 in lizard and frog cells was induced in response to heat shock. Unexpectedly, overexpression of lizard and frog HSF3 as well as HSF1 induced HSP70 expression in mouse cells during heat shock, indicating that the two factors have the potential to induce the HSR. Furthermore, knockdown of either HSF3 or HSF1 markedly reduced HSP70 induction in lizard cells and resistance to heat shock. These results demonstrated that HSF1 and HSF3 cooperatively regulate the HSR at least in lizards, and suggest complex mechanisms of the HSR in lizards as well as frogs.

HSF1 and HSF3 cooperatively regulate the heat shock response in lizards

PubMed Central

Takii, Ryosuke; Fujimoto, Mitsuaki; Matsuura, Yuki; Wu, Fangxu; Oshibe, Namiko; Takaki, Eiichi; Katiyar, Arpit; Akashi, Hiroshi; Makino, Takashi; Kawata, Masakado

2017-01-01

Cells cope with temperature elevations, which cause protein misfolding, by expressing heat shock proteins (HSPs). This adaptive response is called the heat shock response (HSR), and it is regulated mainly by heat shock transcription factor (HSF). Among the four HSF family members in vertebrates, HSF1 is a master regulator of HSP expression during proteotoxic stress including heat shock in mammals, whereas HSF3 is required for the HSR in birds. To examine whether only one of the HSF family members possesses the potential to induce the HSR in vertebrate animals, we isolated cDNA clones encoding lizard and frog HSF genes. The reconstructed phylogenetic tree of vertebrate HSFs demonstrated that HSF3 in one species is unrelated with that in other species. We found that the DNA-binding activity of both HSF1 and HSF3 in lizard and frog cells was induced in response to heat shock. Unexpectedly, overexpression of lizard and frog HSF3 as well as HSF1 induced HSP70 expression in mouse cells during heat shock, indicating that the two factors have the potential to induce the HSR. Furthermore, knockdown of either HSF3 or HSF1 markedly reduced HSP70 induction in lizard cells and resistance to heat shock. These results demonstrated that HSF1 and HSF3 cooperatively regulate the HSR at least in lizards, and suggest complex mechanisms of the HSR in lizards as well as frogs. PMID:28686674

Silkworm Thermal Biology: A Review of Heat Shock Response, Heat Shock Proteins and Heat Acclimation in the Domesticated Silkworm, Bombyx mori

PubMed Central

Manjunatha, H. B.; Rajesh, R. K.; Aparna, H. S.

2010-01-01

Heat shock proteins (HSPs) are known to play ecological and evolutionary roles in this postgenomic era. Recent research suggests that HSPs are implicated in cardiovascular biology and disease development, proliferation and regulation of cancer cells, cell death via apoptosis, and several other key cellular functions. These activities have generated great interest amongst cell and molecular biologists, and these biologists are keen to unravel other hitherto unknown potential functions of this group of proteins. Consequently, the biological significance of HSPs has led to cloning and characterization of genes encoding HSPs in many organisms including the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae). However, most of the past investigations in B. mori were confined to expression of HSPs in tissues and cell lines, whereas information on their specific functional roles in biological, physiological, and molecular processes is scarce. Naturally occurring or domesticated polyvoltines (known to be the tropical race) are more resistant to high temperatures and diseases than bi- or univoltines (temperate races). The mechanism of ecological or evolutionary modification of HSPs during the course of domestication of B. mori - particularly in relation to thermotolerance in geographically distinct races/strains - is still unclear. In addition, the heat shock response, thermal acclimation, and hardening have not been studied extensively in B. mori compared to other organisms. Towards this, recent investigations on differential expression of HSPs at various stages of development, considering the concept of the whole organism, open ample scope to evaluate their biological and commercial importance in B. mori which has not been addressed in any of the representative organisms studied so far. Comparatively, heat shock response among different silkworm races/strains of poly-, bi-, and univoltines varies significantly and thermotolerance increases as the larval development proceeds

Effects of heat shock on neuroblastoma (N1E 115) cell proliferation and differentiation.

PubMed

Stoklosinski, A; Kruse, H; Richter-Landsberg, C; Rensing, L

1992-05-01

Heat shock (44 degrees C) applied for only 15 min induced the development of neurites in neuroblastoma cells 3-6 days later. During the first day after heat shock a transient increase in the rate of cytokinesis together with a synchronizing effect was observed, which led to waves of cytokinesis 14.5 h apart. Individual cell cycles were determined and showed a lengthening in the minimal cell cycle duration and a decrease in the cell cycle variance after shock. Two to 3 days after heat shock the proliferation rate decreased and then recovered. During the 6 days after heat shock, total protein synthesis was lower compared to the untreated cultures. The synthesis of heat shock proteins (100, 90, 84, 70, 68 kDa and some of lower MW) reached a maximum 6 h after heat shock. Parallel changes in the phosphorylation state of proteins were observed in an in vitro assay. Four proteins (100, 89, 67, and 15 kDa) increased and two proteins (97, 73 kDa) decreased their phosphorylation state significantly. Six days after heat shock two proteins (89, 55 kDa) increased their phosphorylation state; the 55-kDa phosphoprotein was identified as tubulin. The effect of heat shock on the intracellular calcium level was determined by measuring Fura 2 fluorescence. Six hours after shock, the Ca2+ level increased to a maximum (about three times the control value) and then dropped during the following days below the control values. We conclude from these results that a decrease in the calcium level may be causally involved in the differentiation process. The calcium effect is probably mediated by changes in the activity of different kinases. This assumption is compatible with the results of experiments with cyclic nucleotides when 10(-5) M cAMP and cGMP were added to in vitro assays of protein phosphorylation. They had different stimulating effects in heat-shocked, differentiating, and growing (control) cells.

Heating a plasma by a broadband stream of fast electrons: Fast ignition, shock ignition, and Gbar shock wave applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gus’kov, S. Yu., E-mail: guskov@sci.lebedev.ru; Nicolai, Ph.; Ribeyre, X.

2015-09-15

An exact analytic solution is found for the steady-state distribution function of fast electrons with an arbitrary initial spectrum irradiating a planar low-Z plasma with an arbitrary density distribution. The solution is applied to study the heating of a material by fast electrons of different spectra such as a monoenergetic spectrum, a step-like distribution in a given energy range, and a Maxwellian spectrum, which is inherent in laser-produced fast electrons. The heating of shock- and fast-ignited precompressed inertial confinement fusion (ICF) targets as well as the heating of a target designed to generate a Gbar shock wave for equation ofmore » state (EOS) experiments by laser-produced fast electrons with a Maxwellian spectrum is investigated. A relation is established between the energies of two groups of Maxwellian fast electrons, which are responsible for generation of a shock wave and heating the upstream material (preheating). The minimum energy of the fast and shock igniting beams as well as of the beam for a Gbar shock wave generation increases with the spectral width of the electron distribution.« less

Shock-wave initiation of heated plastified TATB detonation

NASA Astrophysics Data System (ADS)

Kuzmitsky, Igor; Rudenko, Vladimir; Gatilov, Leonid; Koshelev, Alexandr

1999-06-01

Explosive, plastified TATB, attracts attention with its weak sensitivity to shock loads and high temperature stability ( Pthreshold ? 6.5 GPa and Tcrit ? 250 0Q). However, at its cooling to T 250 0Q plastified TATB becomes as sensitive to shock load as octogen base HE: the excitation threshold reduces down to Pthreshold 2.0 GPa. The main physical reason for the HE sensitivity change is reduction in density at heating and, hence, higher porosity of the product (approximately from 2Moreover, increasing temperature increases the growth rate of uhotf spots which additionally increases the shock sensitivity [1]. Heated TATB experiments are also conducted at VNIIEF. The detonation excitation was computed within 1D program system MAG using EOS JWL for HE and EP and LLNL kinetics [1,2,3]. Early successful results of using this kinetics to predict detonation excitation in heated plastified TATB in VNIIEF experiments with short and long loading pulses are presented. Parameters of the chemical zone of the stationary detonation wave in plastified TATB (LX-17) were computed with the data from [1]. Parameters Heated In shell Cooled Unheated ?0 , g/cm3 1.70 1.81 1.84 1.905 D , km/s 7.982 7.764 7.686 7.517 PN, GPa 45.4 45.8 35.7 32.9 PJ, GPa 27.0 27.3 27.2 26.4 ?x , mm 0.504 0.843 1.041 2.912 ?t , ns 63.1 108.6 135.5 387.4 [1] Effect of Confinement and Thermal Cycling on the Shock Initiation of LX-17 P.A. Urtiew, C.M. Tarver, J.L. Maienschein, and W.C. Tao. LLNL. Combustion and Flame 105: 43-53 (1996) [2] C.M. Tarver, P.A. Urtiew and W.C. Tao (LLNL) Effects of tandem and colliding shock waves on initiation of triaminotrinitrobenzene. J.Appl. Phys. 78(5), September 1995 [3] Craig M. Tarver, John W. Kury and R. Don Breithaupt Detonation waves in triaminotrinitrobenzene J. Appl. Phys. 82(8) , 15 October 1997.

Non-specific protein modifications by a phytochemical induce heat shock response for self-defense.

PubMed

Ohnishi, Kohta; Ohkura, Shinya; Nakahata, Erina; Ishisaka, Akari; Kawai, Yoshichika; Terao, Junji; Mori, Taiki; Ishii, Takeshi; Nakayama, Tsutomu; Kioka, Noriyuki; Matsumoto, Shinya; Ikeda, Yasutaka; Akiyama, Minoru; Irie, Kazuhiro; Murakami, Akira

2013-01-01

Accumulated evidence shows that some phytochemicals provide beneficial effects for human health. Recently, a number of mechanistic studies have revealed that direct interactions between phytochemicals and functional proteins play significant roles in exhibiting their bioactivities. However, their binding selectivities to biological molecules are considered to be lower due to their small and simple structures. In this study, we found that zerumbone, a bioactive sesquiterpene, binds to numerous proteins with little selectivity. Similar to heat-denatured proteins, zerumbone-modified proteins were recognized by heat shock protein 90, a constitutive molecular chaperone, leading to heat shock factor 1-dependent heat shock protein induction in hepa1c1c7 mouse hepatoma cells. Furthermore, oral administration of this phytochemical up-regulated heat shock protein expressions in the livers of Sprague-Dawley rats. Interestingly, pretreatment with zerumbone conferred a thermoresistant phenotype to hepa1c1c7 cells as well as to the nematode Caenorhabditis elegans. It is also important to note that several phytochemicals with higher hydrophobicity or electrophilicity, including phenethyl isothiocyanate and curcumin, markedly induced heat shock proteins, whereas most of the tested nutrients did not. These results suggest that non-specific protein modifications by xenobiotic phytochemicals cause mild proteostress, thereby inducing heat shock response and leading to potentiation of protein quality control systems. We considered these bioactivities to be xenohormesis, an adaptation mechanism against xenobiotic chemical stresses. Heat shock response by phytochemicals may be a fundamental mechanism underlying their various bioactivities.

Non-Specific Protein Modifications by a Phytochemical Induce Heat Shock Response for Self-Defense

PubMed Central

Ohnishi, Kohta; Ohkura, Shinya; Nakahata, Erina; Ishisaka, Akari; Kawai, Yoshichika; Terao, Junji; Mori, Taiki; Ishii, Takeshi; Nakayama, Tsutomu; Kioka, Noriyuki; Matsumoto, Shinya; Ikeda, Yasutaka; Akiyama, Minoru; Irie, Kazuhiro; Murakami, Akira

2013-01-01

Accumulated evidence shows that some phytochemicals provide beneficial effects for human health. Recently, a number of mechanistic studies have revealed that direct interactions between phytochemicals and functional proteins play significant roles in exhibiting their bioactivities. However, their binding selectivities to biological molecules are considered to be lower due to their small and simple structures. In this study, we found that zerumbone, a bioactive sesquiterpene, binds to numerous proteins with little selectivity. Similar to heat-denatured proteins, zerumbone-modified proteins were recognized by heat shock protein 90, a constitutive molecular chaperone, leading to heat shock factor 1-dependent heat shock protein induction in hepa1c1c7 mouse hepatoma cells. Furthermore, oral administration of this phytochemical up-regulated heat shock protein expressions in the livers of Sprague-Dawley rats. Interestingly, pretreatment with zerumbone conferred a thermoresistant phenotype to hepa1c1c7 cells as well as to the nematode Caenorhabditis elegans. It is also important to note that several phytochemicals with higher hydrophobicity or electrophilicity, including phenethyl isothiocyanate and curcumin, markedly induced heat shock proteins, whereas most of the tested nutrients did not. These results suggest that non-specific protein modifications by xenobiotic phytochemicals cause mild proteostress, thereby inducing heat shock response and leading to potentiation of protein quality control systems. We considered these bioactivities to be xenohormesis, an adaptation mechanism against xenobiotic chemical stresses. Heat shock response by phytochemicals may be a fundamental mechanism underlying their various bioactivities. PMID:23536805

Heat shock response and mammal adaptation to high elevation (hypoxia).

PubMed

Wang, Xiaolin; Xu, Cunshuan; Wang, Xiujie; Wang, Dongjie; Wang, Qingshang; Zhang, Baochen

2006-10-01

The mammal's high elevation (hypoxia) adaptation was studied by using the immunological and the molecular biological methods to understand the significance of Hsp (hypoxia) adaptation in the organic high elevation, through the mammal heat shock response. (1) From high elevation to low elevation (natural hypoxia): Western blot and conventional RT-PCR and real-time fluorescence quota PCR were adopted. Expression difference of heat shock protein of 70 (Hsp70) and natural expression of brain tissue of Hsp70 gene was determined in the cardiac muscle tissue among the different elevation mammals (yak). (2) From low elevation to high elevation (hypoxia induction): The mammals (domestic rabbits) from the low elevation were sent directly to the areas with different high elevations like 2300, 3300 and 5000 m above sea level to be raised for a period of 3 weeks before being slaughtered and the genetic inductive expression of the brain tissue of Hsp70 was determined with RT-PCR. The result indicated that all of the mammals at different elevations possessed their heat shock response gene. Hsp70 of the high elevation mammal rose abruptly under stress and might be induced to come into being by high elevation (hypoxia). The speedy synthesis of Hsp70 in the process of heat shock response is suitable to maintain the cells' normal physiological functions under stress. The Hsp70 has its threshold value. The altitude of 5000 m above sea level is the best condition for the heat shock response, and it starts to reduce when the altitude is over 6000 m above sea level. The Hsp70 production quantity and the cell hypoxia bearing capacity have their direct ratio.

The differential effects of heat-shocking on the viability of spores from Bacillus anthracis, Bacillus subtilis, and Clostridium sporogenes after treatment with peracetic acid- and glutaraldehyde-based disinfectants

PubMed Central

March, Jordon K; Pratt, Michael D; Lowe, Chinn-Woan; Cohen, Marissa N; Satterfield, Benjamin A; Schaalje, Bruce; O'Neill, Kim L; Robison, Richard A

2015-01-01

This study investigated (1) the susceptibility of Bacillus anthracis (Ames strain), Bacillus subtilis (ATCC 19659), and Clostridium sporogenes (ATCC 3584) spores to commercially available peracetic acid (PAA)- and glutaraldehyde (GA)-based disinfectants, (2) the effects that heat-shocking spores after treatment with these disinfectants has on spore recovery, and (3) the timing of heat-shocking after disinfectant treatment that promotes the optimal recovery of spores deposited on carriers. Suspension tests were used to obtain inactivation kinetics for the disinfectants against three spore types. The effects of heat-shocking spores after disinfectant treatment were also determined. Generalized linear mixed models were used to estimate 6-log reduction times for each spore type, disinfectant, and heat treatment combination. Reduction times were compared statistically using the delta method. Carrier tests were performed according to AOAC Official Method 966.04 and a modified version that employed immediate heat-shocking after disinfectant treatment. Carrier test results were analyzed using Fisher's exact test. PAA-based disinfectants had significantly shorter 6-log reduction times than the GA-based disinfectant. Heat-shocking B. anthracis spores after PAA treatment resulted in significantly shorter 6-log reduction times. Conversely, heat-shocking B. subtilis spores after PAA treatment resulted in significantly longer 6-log reduction times. Significant interactions were also observed between spore type, disinfectant, and heat treatment combinations. Immediately heat-shocking spore carriers after disinfectant treatment produced greater spore recovery. Sporicidal activities of disinfectants were not consistent across spore species. The effects of heat-shocking spores after disinfectant treatment were dependent on both disinfectant and spore species. Caution must be used when extrapolating sporicidal data of disinfectants from one spore species to another. Heat-shocking

Analysis of the Bacterial Heat Shock Response to Photodynamic Therapy-Mediated Oxidative Stress

PubMed Central

St. Denis, Tyler G.; Huang, Liyi; Dai, Tianhong; Hamblin, Michael R.

2011-01-01

Antimicrobial photodynamic therapy (PDT) has recently emerged as an effective modality for the selective destruction of bacteria and other pathogenic microorganisms. We investigated whether PDT induced protective responses such as heat shock proteins in bacteria. Using the photosensitizer Toluidine Blue O (TBO) at sub-lethal PDT conditions, a 7-fold increase in bacterial heat shock protein GroEL and a 3-fold increase in heat shock protein DnaK were observed in Escherichia coli post PDT. Pretreatment with 50o C heat for 30 minutes reduced PDT killing in both E. coli and in Enterococcus faecalis, with the most pronounced inhibition occurring at 50-μM TBO with 5-J/cm2 635 nm light, where E. coli killing was reduced by 2- log10 and E. faecalis killing was reduced by 4-log10. Finally, inhibition of the highly conserved chaperone DnaK using a small molecule benzylidene lactam heat shock protein inhibitor potentiated (but not significantly) the effect of PDT at a TBO concentration of 2.5 μM in E. faecalis; however, this effect was not observed in E. coli presumably because inhibitor could not gain access due to Gram-negative permeability barrier. Induction of heat shock proteins may be a mechanism whereby bacteria could become resistant to PDT and warrants the need for further study in the application of dual PDT-heat shock protein-inhibition therapies. PMID:21261628

Heat shock factor 1 induces crystallin-αB to protect against cisplatin nephrotoxicity

PubMed Central

Lou, Qiang; Hu, Yanzhong; Ma, Yuanfang

2016-01-01

Cisplatin, a wildly used chemotherapy drug, induces nephrotoxicity that is characterized by renal tubular cell apoptosis. In response to toxicity, tubular cells can activate cytoprotective mechanisms, such as the heat shock response. However, the role and regulation of the heat shock response in cisplatin-induced nephrotoxicity remain largely unclear. In the present study, we demonstrated the induction of heat shock factor (Hsf)1 and the small heat shock protein crystallin-αB (CryAB) during cisplatin nephrotoxicity in mice. Consistently, cisplatin induced Hsf1 and CryAB in a cultured renal proximal tubular cells (RPTCs). RPTCs underwent apoptosis during cisplatin treatment, which was increased when Hsf1 was knocked down. Transfection or restoration of Hsf1 into Hsf1 knockdown cells suppressed cisplatin-induced apoptosis, further supporting a cytoprotective role of Hsf1 and its associated heat shock response. Moreover, Hsf1 knockdown increased Bax translocation to mitochondria and cytochrome c release into the cytosol. In RPTCs, Hsf1 knockdown led to a specific downregulation of CryAB. Transfection of CryAB into Hsf1 knockdown cells diminished their sensitivity to cisplatin-induced apoptosis, suggesting that CryAB may be a key mediator of the cytoprotective effect of Hsf1. Taken together, these results demonstrate a heat shock response in cisplatin nephrotoxicity that is mediated by Hsf1 and CryAB to protect tubular cells against apoptosis. PMID:27194715

Test of a new heat-flow equation for dense-fluid shock waves.

PubMed

Holian, Brad Lee; Mareschal, Michel; Ravelo, Ramon

2010-09-21

Using a recently proposed equation for the heat-flux vector that goes beyond Fourier's Law of heat conduction, we model shockwave propagation in the dense Lennard-Jones fluid. Disequilibrium among the three components of temperature, namely, the difference between the kinetic temperature in the direction of a planar shock wave and those in the transverse directions, particularly in the region near the shock front, gives rise to a new transport (equilibration) mechanism not seen in usual one-dimensional heat-flow situations. The modification of the heat-flow equation was tested earlier for the case of strong shock waves in the ideal gas, which had been studied in the past and compared to Navier-Stokes-Fourier solutions. Now, the Lennard-Jones fluid, whose equation of state and transport properties have been determined from independent calculations, allows us to study the case where potential, as well as kinetic contributions are important. The new heat-flow treatment improves the agreement with nonequilibrium molecular-dynamics simulations under strong shock wave conditions, compared to Navier-Stokes.

Lysosomal responses to heat-shock of seasonal temperature extremes in Cd-exposed mussels.

PubMed

Múgica, M; Izagirre, U; Marigómez, I

2015-07-01

The present study was aimed at determining the effect of temperature extremes on lysosomal biomarkers in mussels exposed to a model toxic pollutant (Cd) at different seasons. For this purpose, temperature was elevated 10°C (from 12°C to 22°C in winter and from 18°C to 28°C in summer) for a period of 6h (heat-shock) in control and Cd-exposed mussels, and then returned back to initial one. Lysosomal membrane stability and lysosomal structural changes in digestive gland were investigated. In winter, heat-shock reduced the labilisation period (LP) of the lysosomal membrane, especially in Cd-exposed mussels, and provoked transient lysosomal enlargement. LP values recovered after the heat-shock cessation but lysosomal enlargement prevailed in both experimental groups. In summer, heat-shock induced remarkable reduction in LP and lysosomal enlargement (more markedly in Cd-exposed mussels), which recovered within 3 days. Besides, whilst heat-shock effects on LP were practically identical for Cd-exposed mussels in winter and summer, the effects were longer-lasting in summer than in winter for control mussels. Thus, lysosomal responsiveness after heat-shock was higher in summer than in winter but recovery was faster as well, and therefore the consequences of the heat shock seem to be more decisive in winter. In contrast, inter-season differences were attenuated in the presence of Cd. Consequently, mussels seem to be better prepared in summer than in winter to stand short periods of abrupt temperature change; this is, however, compromised when mussels are exposed to pollutants such as Cd. Copyright © 2015 Elsevier B.V. All rights reserved.

Changes in the transcriptome of morula-stage bovine embryos caused by heat shock: relationship to developmental acquisition of thermotolerance

PubMed Central

2013-01-01

Background While initially sensitive to heat shock, the bovine embryo gains thermal resistance as it progresses through development so that physiological heat shock has little effect on development to the blastocyst stage by Day 5 after insemination. Here, experiments using 3’ tag digital gene expression (3’DGE) and real-time PCR were conducted to determine changes in the transcriptome of morula-stage bovine embryos in response to heat shock (40 degrees C for 8 h) that could be associated with thermotolerance. Results Using 3’DGE, expression of 173 genes were modified by heat shock, with 94 genes upregulated by heat shock and 79 genes downregulated by heat shock. A total of 38 differentially-regulated genes were associated with the ubiquitin protein, UBC. Heat shock increased expression of one heat shock protein gene, HSPB11, and one heat shock protein binding protein, HSPBP1, tended to increase expression of HSPA1A and HSPB1, but did not affect expression of 64 other genes encoding heat shock proteins, heat shock transcription factors or proteins interacting with heat shock proteins. Moreover, heat shock increased expression of five genes associated with oxidative stress (AKR7A2, CBR1, GGH, GSTA4, and MAP2K5), decreased expression of HIF3A, but did not affect expression of 42 other genes related to free radical metabolism. Heat shock also had little effect on genes involved in embryonic development. Effects of heat shock for 2, 4 and 8 h on selected heat shock protein and antioxidant genes were also evaluated by real-time PCR. Heat shock increased steady-state amounts of mRNA for HSPA1A (P<0.05) and tended to increase expression of HSP90AA1 (P<0.07) but had no effect on expression of SOD1 or CAT. Conclusions Changes in the transcriptome of the heat-shocked bovine morula indicate that the embryo is largely resistant to effects of heat shock. As a result, transcription of genes involved in thermal protection is muted and there is little disruption of gene

Cardioprotective effects of 70-kDa heat shock protein in transgenic mice.

PubMed

Radford, N B; Fina, M; Benjamin, I J; Moreadith, R W; Graves, K H; Zhao, P; Gavva, S; Wiethoff, A; Sherry, A D; Malloy, C R; Williams, R S

1996-03-19

Heat shock proteins are proposed to limit injury resulting from diverse environmental stresses, but direct metabolic evidence for such a cytoprotective function in vertebrates has been largely limited to studies of cultured cells. We generated lines of transgenic mice to express human 70-kDa heat shock protein constitutively in the myocardium. Hearts isolated from these animals demonstrated enhanced recovery of high energy phosphate stores and correction of metabolic acidosis following brief periods of global ischemia sufficient to induce sustained abnormalities of these variables in hearts from nontransgenic littermates. These data demonstrate a direct cardioprotective effect of 70-kDa heat shock protein to enhance postischemic recovery of the intact heart.

Chalcones from Angelica keiskei: Evaluation of Their Heat Shock Protein Inducing Activities.

PubMed

Kil, Yun-Seo; Choi, Seul-Ki; Lee, Yun-Sil; Jafari, Mahtab; Seo, Eun-Kyoung

2015-10-23

Five new chalcones, 4,2',4'-trihydroxy-3'-[(2E,5E)-7-methoxy-3,7-dimethyl-2,5-octadienyl]chalcone (1), (±)-4,2',4'-trihydroxy-3'-[(2E)-6-hydroxy-7-methoxy-3,7-dimethyl-2-octenyl]chalcone (2), 4,2',4'-trihydroxy-3'-[(2E)-3-methyl-5-(1,3-dioxolan-2-yl)-2-pentenyl]chalcone (3), 2',3'-furano-4-hydroxy-4'-methoxychalcone (4), and (±)-4-hydroxy-2',3'-(2,3-dihydro-2-methoxyfurano)-4'-methoxychalcone (5), were isolated from the aerial parts of Angelica keiskei Koidzumi together with eight known chalcones, 6-13, which were identified as (±)-4,2',4'-trihydroxy-3'-[(6E)-2-hydroxy-7-methyl-3-methylene-6-octenyl]chalcone (6), xanthoangelol (7), xanthoangelol F (8), xanthoangelol G (9), 4-hydroxyderricin (10), xanthoangelol D (11), xanthoangelol E (12), and xanthoangelol H (13), respectively. Chalcones 1-13 were evaluated for their promoter activity on heat shock protein 25 (hsp25, murine form of human hsp27). Compounds 1 and 6 activated the hsp25 promoter by 21.9- and 29.2-fold of untreated control at 10 μM, respectively. Further protein expression patterns of heat shock factor 1 (HSF1), HSP70, and HSP27 by 1 and 6 were examined. Compound 6 increased the expression of HSF1, HSP70, and HSP27 by 4.3-, 1.5-, and 4.6-fold of untreated control, respectively, without any significant cellular cytotoxicities, whereas 1 did not induce any expression of these proteins. As a result, 6 seems to be a prospective HSP inducer.

A minimal titration model of the mammalian dynamical heat shock response

NASA Astrophysics Data System (ADS)

Sivéry, Aude; Courtade, Emmanuel; Thommen, Quentin

2016-12-01

Environmental stress, such as oxidative or heat stress, induces the activation of the heat shock response (HSR) and leads to an increase in the heat shock proteins (HSPs) level. These HSPs act as molecular chaperones to maintain cellular proteostasis. Controlled by highly intricate regulatory mechanisms, having stress-induced activation and feedback regulations with multiple partners, the HSR is still incompletely understood. In this context, we propose a minimal molecular model for the gene regulatory network of the HSR that reproduces quantitatively different heat shock experiments both on heat shock factor 1 (HSF1) and HSPs activities. This model, which is based on chemical kinetics laws, is kept with a low dimensionality without altering the biological interpretation of the model dynamics. This simplistic model highlights the titration of HSF1 by chaperones as the guiding line of the network. Moreover, by a steady states analysis of the network, three different temperature stress regimes appear: normal, acute, and chronic, where normal stress corresponds to pseudo thermal adaption. The protein triage that governs the fate of damaged proteins or the different stress regimes are consequences of the titration mechanism. The simplicity of the present model is of interest in order to study detailed modelling of cross regulation between the HSR and other major genetic networks like the cell cycle or the circadian clock.

Cardioprotective effects of 70-kDa heat shock protein in transgenic mice.

PubMed Central

Radford, N B; Fina, M; Benjamin, I J; Moreadith, R W; Graves, K H; Zhao, P; Gavva, S; Wiethoff, A; Sherry, A D; Malloy, C R; Williams, R S

1996-01-01

Heat shock proteins are proposed to limit injury resulting from diverse environmental stresses, but direct metabolic evidence for such a cytoprotective function in vertebrates has been largely limited to studies of cultured cells. We generated lines of transgenic mice to express human 70-kDa heat shock protein constitutively in the myocardium. Hearts isolated from these animals demonstrated enhanced recovery of high energy phosphate stores and correction of metabolic acidosis following brief periods of global ischemia sufficient to induce sustained abnormalities of these variables in hearts from nontransgenic littermates. These data demonstrate a direct cardioprotective effect of 70-kDa heat shock protein to enhance postischemic recovery of the intact heart. Images Fig. 1 Fig. 3 PMID:8637874

Heat shock increases oxidative stress to modulate growth and physico-chemical attributes in diverse maize cultivars

NASA Astrophysics Data System (ADS)

Hussain, Iqbal; Ashraf, Muhammad Arslan; Rasheed, Rizwan; Iqbal, Muhammad; Ibrahim, Muhammad; Ashraf, Shamila

2016-10-01

The present investigation was conducted to appraise the physiochemical adjustments in contrasting maize cultivars, namely, PakAfgoi (tolerant) and EV-5098 (sensitive) subjected to heat shock. Seven-day-old seedlings were exposed to heat shock for different time intervals (1, 3, 6, 24, 48 and 72 h) and data for various physiochemical attributes determined to appraise time course changes in maize. After 72 h of heat shock, the plants were grown under normal conditions for 5 d and data for different growth attributes and photosynthetic pigments recorded. Exposure to heat shock reduced growth and photosynthetic pigments in maize cultivars. The plants exposed to heat shock for up to 3 h recovered growth and photosynthetic pigments when stress was relieved. A time course rise in the relative membrane permeability, hydrogen peroxide (H2O2) and malondialdehyde contents was recorded particularly in the EV-5098 indicating that heat shock-induced oxidative stress. Activities of different enzymatic antioxidants greatly altered due to heat shock. For instance, an increase in superoxide dismutase activity was recorded in both maize cultivars. The activity of ascorbate peroxidase was greater in Pak-Afgoi. However, the peroxidase and catalase activities were higher in plants of EV-5098. Heat shock caused a significant rise in the proline and decline in the total free amino acids. Overall, the performance of Pak-Afgoi was better in terms of having lesser oxidative damage and greater cellular levels of proline. The results suggested that oxidative stress indicators (relative membrane permeability, H2O2 and malondialdehyde) and proline can be used as markers for heat shock tolerant plants.

Functional analysis of Drosophila HSP70 promoter with different HSE numbers in human cells.

PubMed

Kust, Nadezda; Rybalkina, Ekaterina; Mertsalov, Ilya; Savchenko, Ekaterina; Revishchin, Alexander; Pavlova, Gali

2014-01-01

The activation of genetic constructs including the Drosophila hsp70 promoter with four and eight HSE sequences in the regulatory region has been described in human cells. The promoter was shown to be induced at lower temperatures compared to the human hsp70 promoter. The promoter activity increased after a 60-min heat shock already at 38 °C in human cells. The promoter activation was observed 24 h after heat shock for the constructs with eight HSEs, while those with four HSEs required 48 h. After transplantation of in vitro heat-shocked transfected cells, the promoter activity could be maintained for 3 days with a gradual decline. The promoter activation was confirmed in vivo without preliminary heat shock in mouse ischemic brain foci. Controlled expression of the Gdnf gene under a Drosophila hsp70 promoter was demonstrated. This promoter with four and eight HSE sequences in the regulatory region can be proposed as a regulated promoter in genetic therapeutic systems.

Heat shock suppresses mating and sperm transfer in the rice leaf folder Cnaphalocrocis medinalis.

PubMed

Liao, H J; Qian, Q; Liu, X D

2014-06-01

Temperature is a key environmental factor in determining the population size of Cnaphalocrocis medinalis in summer. High temperatures inhibit survival, development and fecundity of this insect. However, biological responses of female and male adults to heat shock, and physiological mechanism of high temperature suppressing population development are still ambiguous. We experimentally tested the impact of heat shock (5 h day-1) on biological traits, spermatogenesis and sperm transfer of adults of C. medinalis. The result showed that heat exposure to 39 and 40 °C for 5 h reduced longevity and copulation frequency of adults, and hatchability of eggs. Immediate survival rate of males was lower than that of females after 3 days of exposure to 41 °C. The oviposition period, copulation frequency, fecundity of adults and hatchability of eggs were significantly lower when male adults were exposed to 40 or 41 °C for 3 days. Heat shock decreased frequency and success rate of mating when males were exposed, and it also resulted in postponement of mating behaviour and prolongation of mating duration as both the female and male adults were exposed. Heat shock did not affect spermatogenesis, but significantly inhibited sperms maturation. Moreover, males could not ejaculate sperm into females during copulation when these male moths received heat shock. Heat shock remarkably suppressed mating behaviour and sperm transfer, which led to a dramatic decline of rice leaf folder populations.

The differential effects of heat-shocking on the viability of spores from Bacillus anthracis, Bacillus subtilis, and Clostridium sporogenes after treatment with peracetic acid- and glutaraldehyde-based disinfectants.

PubMed

March, Jordon K; Pratt, Michael D; Lowe, Chinn-Woan; Cohen, Marissa N; Satterfield, Benjamin A; Schaalje, Bruce; O'Neill, Kim L; Robison, Richard A

2015-10-01

This study investigated (1) the susceptibility of Bacillus anthracis (Ames strain), Bacillus subtilis (ATCC 19659), and Clostridium sporogenes (ATCC 3584) spores to commercially available peracetic acid (PAA)- and glutaraldehyde (GA)-based disinfectants, (2) the effects that heat-shocking spores after treatment with these disinfectants has on spore recovery, and (3) the timing of heat-shocking after disinfectant treatment that promotes the optimal recovery of spores deposited on carriers. Suspension tests were used to obtain inactivation kinetics for the disinfectants against three spore types. The effects of heat-shocking spores after disinfectant treatment were also determined. Generalized linear mixed models were used to estimate 6-log reduction times for each spore type, disinfectant, and heat treatment combination. Reduction times were compared statistically using the delta method. Carrier tests were performed according to AOAC Official Method 966.04 and a modified version that employed immediate heat-shocking after disinfectant treatment. Carrier test results were analyzed using Fisher's exact test. PAA-based disinfectants had significantly shorter 6-log reduction times than the GA-based disinfectant. Heat-shocking B. anthracis spores after PAA treatment resulted in significantly shorter 6-log reduction times. Conversely, heat-shocking B. subtilis spores after PAA treatment resulted in significantly longer 6-log reduction times. Significant interactions were also observed between spore type, disinfectant, and heat treatment combinations. Immediately heat-shocking spore carriers after disinfectant treatment produced greater spore recovery. Sporicidal activities of disinfectants were not consistent across spore species. The effects of heat-shocking spores after disinfectant treatment were dependent on both disinfectant and spore species. Caution must be used when extrapolating sporicidal data of disinfectants from one spore species to another. Heat-shocking

Shock compression and flash-heating of molecular adsorbates on the picosecond time scale

NASA Astrophysics Data System (ADS)

Berg, Christopher Michael

An ultrafast nonlinear coherent laser spectroscopy termed broadband multiplex vibrational sum-frequency generation (SFG) with nonresonant suppression was employed to monitor vibrational transitions of molecular adsorbates on metallic substrates during laser-driven shock compression and flash-heating. Adsorbates were in the form of well-ordered self-assembled monolayers (SAMs) and included molecular explosive simulants, such as nitroaromatics, and long chain-length alkanethiols. Based on reflectance measurements of the metallic substrates, femtosecond flash-heating pulses were capable of producing large-amplitude temperature jumps with DeltaT = 500 K. Laser-driven shock compression of SAMs produced pressures up to 2 GPa, where 1 GPa ≈ 1 x 104 atm. Shock pressures were estimated via comparison with frequency shifts observed in the monolayer vibrational transitions during hydrostatic pressure measurements in a SiC anvil cell. Molecular dynamics during flash-heating and shock loading were probed with vibrational SFG spectroscopy with picosecond temporal resolution and sub-nanometer spatial resolution. Flash-heating studies of 4-nitrobenzenethiolate (NBT) on Au provided insight into effects from hot-electron excitation of the molecular adsorbates at early pump-probe delay times. At longer delay times, effects from the excitation of SAM lattice modes and lower-energy NBT vibrations were shown. In addition, flash-heating studies of alkanethiolates demonstrated chain disordering behaviors as well as interface thermal conductances across the Au-SAM junction, which was of specific interest within the context of molecular electronics. Shock compression studies of molecular explosive simulants, such as 4-nitrobenzoate (NBA), demonstrated the proficiency of this technique to observe shock-induced molecular dynamics, in this case orientational dynamics, on the picosecond time scale. Results validated the utilization of these refined shock loading techniques to probe the shock

Examine the Correlation between Heat Shock Protein IbpA and Heat Tolerance in Cronobacter sakazakii.

PubMed

Zhao, Zhi Jing; Wang, Bin; Yuan, Jing; Liang, Hao Yu; Dong, Si Guo; Zeng, Ming

2017-08-01

We used a proteomic approach to identify IbpA in Cronobacter sakazakii (C. sakazaki), which is related to heat tolerance in this strain. The abundance of IbpA in C. sakazakii strains strongly increased after heat shock. C. sakazakii CMCC 45402 ibpA deletion mutants were successfully constructed. The C. sakazakii CMCC 45402 ΔibpA and wild-type strains could not be distinguished based on colony morphology on LB agar plates or biochemical assays. The growth of the C. sakazakii CMCC 45402 ΔibpA mutant in heat shock conditions was indistinguishable from that of the isogenic wild-type, but showed greater heat resistance than E. coli O157:H7 strain CMCC 44828. This study suggests that the absence of a single ibpA gene has no obvious effect on the phenotype or heat resistance of the strain C. sakazakii CMCC 45402. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Shock-Bubble Heating of the Intracluster Medium

NASA Astrophysics Data System (ADS)

Friedman, Samuel H.; Heinz, S.; Churazov, E.

2011-01-01

Active galactic nuclei (AGN) Feedback via extragalactic jets requires a thermalization of the energy injected into the intracluster medium (ICM) in order for energy feedback to occur. Heinz and Churazov (2005) proposed a method using shock waves and previously inflated bubbles in the ICM to extract energy from the shock waves and turn the energy into rotational kinetic energy. This energy would decay and allow heating to occur elsewhere throughout the galaxy cluster. In this paper, we extend to three dimensions (3D) the previous work using hydrodynamic simulations. We also compare our results to previous related work done performed experimentally.

Protein Kinase A Regulates Constitutive Expression of Small Heat-Shock Genes in an Msn2/4p-Independent and Hsf1p-Dependent Manner in Saccharomyces cerevisiae

PubMed Central

Ferguson, Scott B.; Anderson, Erik S.; Harshaw, Robyn B.; Thate, Tim; Craig, Nancy L.; Nelson, Hillary C. M.

2005-01-01

Hsf1p, the heat-shock transcription factor from Saccharomyces cerevisiae, has a low level of constitutive transcriptional activity and is kept in this state through negative regulation. In an effort to understand this negative regulation, we developed a novel genetic selection that detects altered expression from the HSP26 promoter. Using this reporter strain, we identified mutations and dosage compensators in the Ras/cAMP signaling pathway that decrease cAMP levels and increase expression from the HSP26 promoter. In yeast, low cAMP levels reduce the catalytic activity of the cAMP-dependent kinase PKA. Previous studies had proposed that the stress response transcription factors Msn2p/4p, but not Hsf1p, are repressed by PKA. However, we found that reduction or elimination of PKA activity strongly derepresses transcription of the small heat-shock genes HSP26 and HSP12, even in the absence of MSN2/4. In a strain deleted for MSN2/4 and the PKA catalytic subunits, expression of HSP12 and HSP26 depends on HSF1 expression. Our findings indicate that Hsf1p functions downstream of PKA and suggest that PKA might be involved in negative regulation of Hsf1p activity. These results represent a major change in our understanding of how PKA signaling influences the heat-shock response and heat-shock protein expression. PMID:15545649

Heat shock proteins and toll-like receptors.

PubMed

Asea, Alexzander

2008-01-01

Researchers have only just begun to elucidate the relationship between heat shock proteins (HSP) and Toll-like receptors (TLR). HSP were originally described as an intracellular molecular chaperone of naïve, aberrantly folded, or mutated proteins and primarily implicated as a cytoprotective protein when cells are exposed to stressful stimuli. However, recent studies have ascribed novel functions to the Hsp70 protein depending on its localization: Surface-bound Hsp70 specifically activate natural killer (NK) cells, while Hsp70 released into the extracellular milieu specifically bind to Toll-like receptors (TLR) 2 and 4 on antigen-presenting cells (APC) and exerts immunoregulatory effects, including upregulation of adhesion molecules, co-stimulatory molecule expression, and cytokine and chemokine release-a process known as the chaperokine activity of Hsp70. This chapter discusses the most recent advances in the understanding of heat shock protein (HSP) and TLR interactions in general and highlights recent findings that demonstrate Hsp70 is a ligand for TLR and its biological significance.

OLA1 protects cells in heat shock by stabilizing HSP70

PubMed Central

Mao, R-F; Rubio, V; Chen, H; Bai, L; Mansour, O C; Shi, Z-Z

2013-01-01

The heat-shock response is an evolutionarily conserved cellular defense mechanism against environmental stresses, characterized by the rapid synthesis of heat-shock proteins (HSPs). HSP70, a highly inducible molecular chaperone, assists in refolding or clearance of damaged proteins, thereby having a central role in maintaining intracellular homeostasis and thermotolerance. To date, induction of HSP70 expression has been described extensively at the transcriptional level. However, post-translational regulation of HSP70, such as protein stability, is only partially understood. In this study, we investigated the role of OLA1 (Obg-like ATPase 1), a previously uncharacterized cytosolic ATPase, in regulating the turnover of HSP70. Downregulation of OLA1 in mammalian cells by either RNAi or targeted gene disruption results in reduced steady-state levels of HSP70, impaired HSP70 induction by heat, and functionally, increased cellular sensitivity to heat shock. Conversely, overexpression of OLA1 correlates with elevated HSP70 protein levels and improved thermal resistance. Protein–protein interaction assays demonstrated that binding of OLA1 to the HSP70 carboxyl terminus variable domain hinders the recruitment of CHIP (C-terminus of Hsp70-binding protein), an E3 ubiquitin ligase for HSP70, and thus prevents HSP70 from the CHIP-mediated ubiquitination. These findings suggest a novel molecular mechanism by which OLA1 stabilizes HSP70, leading to upregulation of HSP70 as well as increased survival during heat shock. PMID:23412384

Reversible electron heating vs. wave-particle interactions in quasi-perpendicular shocks

NASA Technical Reports Server (NTRS)

Veltri, P.; Mangeney, A.; Scudder, J. D.

1992-01-01

The energy necessary to explain the electron heating in quasi-perpendicular collisionless shocks can be derived either from the electron acceleration in the d.c. cross shock electric potential, or by the interactions between the electrons and the waves existing in the shock. A Monte Carlo simulation has been performed to study the electron distribution function evolution through the shock structure, with and without particle diffusion on waves. This simulation has allowed us to clarify the relative importance of the two possible energy sources; in particular it has been shown that the electron parallel temperature is determined by the d.c. electromagnetic field and not by any wave-particle-induced heating. Wave particle interactions are effective in smoothing out the large gradients in phase space produced by the 'reversible' motion of the electrons, thus producing a 'cooling' of the electrons.

Efficient electron heating in relativistic shocks and gamma-ray-burst afterglow.

PubMed

Gedalin, M; Balikhin, M A; Eichler, D

2008-02-01

Electrons in shocks are efficiently energized due to the cross-shock potential, which develops because of differential deflection of electrons and ions by the magnetic field in the shock front. The electron energization is necessarily accompanied by scattering and thermalization. The mechanism is efficient in both magnetized and nonmagnetized relativistic electron-ion shocks. It is proposed that the synchrotron emission from the heated electrons in a layer of strongly enhanced magnetic field is responsible for gamma-ray-burst afterglows.

Molecular changes associated with heat-shock treatment in avian mononuclear and lymphoid lineage cells.

PubMed

Miller, L; Qureshi, M A

1992-03-01

The induction of heat-shock protein (HSP) synthesis in avian cells of the mononuclear phagocytic system (MPS) and lymphoid system (LS) lineage was investigated by exposure to in vitro heat-shock conditions. In addition, the kinetics of HSP90 mRNA expression was examined in chicken peritoneal macrophages (PM) as well as heat-shock-induced HSP synthesis in PM from chickens, turkeys, quail, and ducks. Each MPS and LS cell type expressed three major (23, 70, and 90 kDa) HSP following a 1-h heat shock at 45 C. However, a unique heat-induced 32-kDa protein (P32) was expressed only by cells of MPS lineage. The expression of HSP90 mRNA in chicken PM was temperature- and time-dependent. These findings imply that avian PM undergo molecular changes in response to elevated environmental temperatures and that the pattern of HSP expression appears to be distinct for cells of the MPS and LS lineages in chickens.

Heat shock protein 70 in the rat nasal cavity: localisation and response to hyperthermia.

PubMed

Simpson, Sharon A; Alexander, David J; Reed, Celia J

2004-06-01

Heat shock proteins (HSPs) are a group of proteins that are rapidly induced in response to physiological stress, including hyperthermia and exposure to toxicants. Thus they may provide a useful index of toxicity in in vitro systems for screening for toxicity. We have recently developed a rat nasal explant system for investigating upper respiratory tract toxicity, and the aims of this study were to localise HSP70 within the rat nasal cavity and to characterise its response to hyperthermia. Constitutively, HSP70 was found to be predominantly localised to the sustentacular cells, basal cells and Bowman's glands of the olfactory epithelium (OE), with the most intense immunohistochemical staining at levels 3 and 4 of the posterior of the rat nasal cavity. Ethmoturbinates (ETs) and liver slices were exposed to heat shock (37 degrees and 43 degrees C, respectively) for 45 min and then returned to normal culture temperatures (31 degrees and 37 degrees C, respectively) for 24 h. In ETs, HSP72 was maximally induced 4-fold at 4 h after heat shock, and levels then returned to those of control tissue. ATP concentrations were markedly decreased up to 4 h after heat shock and then returned to control levels. In contrast, HSP72 levels in liver slices increased and ATP levels decreased steadily throughout the 24 h culture period. ETs were also able to withstand a 45-min heat shock at 43 degrees C, that is 12 degrees C above normal culture temperature. Incubation of ETs with cycloheximide prior to heat shock reduced the ability of the OE to recover from heat shock at 37 degrees C. Thus the OE of the rat nasal cavity expresses HSP72, and this protein appears to play an important role in the ability of the tissue to withstand hyperthermia.

Effect of diadenosine tetraphosphate microinjection on heat shock protein synthesis in Xenopus laevis oocytes.

PubMed Central

Guedon, G; Sovia, D; Ebel, J P; Befort, N; Remy, P

1985-01-01

Bisnucleosides polyphosphates are thought to be chemical messengers signalling to the cell the onset of various stresses. Diadenosine tri- and tetraphosphates (respectively, Ap3A and Ap4A) accumulate in prokaryotic and eukaryotic cells under heat shock conditions, suggesting they could trigger the synthesis of heat shock proteins (hsps). In this study, Ap4A, Ap3A and, as a control, Ap4 (adenosine tetraphosphate) were injected into Xenopus oocytes. Whereas none of these compounds is able to trigger the synthesis of hsps in the absence of hyperthermic treatment, nuclear microinjection of Ap4A after a mild heat shock specifically enhances the synthesis of the 70-kd hsp, which is involved in the regulation and possibly the termination of the heat shock response. The microinjection of Ap4A prior to the hyperthermic treatment results in a strong inhibition of hsps synthesis (with the exception of the 70-kd hsp) suggesting that Ap4A is involved in the regulation and/or termination of the heat shock response. Ap3A and Ap4 do not induce any detectable modification of hsps expression. Images Fig. 1. Fig. 2. Fig. 4. Fig. 5. PMID:4092696

Electron heating in a Monte Carlo model of a high Mach number, supercritical, collisionless shock

NASA Technical Reports Server (NTRS)

Ellison, Donald C.; Jones, Frank C.

1987-01-01

Preliminary work in the investigation of electron injection and acceleration at parallel shocks is presented. A simple model of electron heating that is derived from a unified shock model which includes the effects of an electrostatic potential jump is described. The unified shock model provides a kinetic description of the injection and acceleration of ions and a fluid description of electron heating at high Mach number, supercritical, and parallel shocks.

Unconventional Secretion of Heat Shock Proteins in Cancer

PubMed Central

Santos, Tiago Góss; Martins, Vilma Regina; Hajj, Glaucia Noeli Maroso

2017-01-01

Heat shock proteins (HSPs) are abundant cellular proteins involved with protein homeostasis. They have both constitutive and inducible isoforms, whose expression levels are further increased by stress conditions, such as temperature elevation, reduced oxygen levels, infection, inflammation and exposure to toxic substances. In these situations, HSPs exert a pivotal role in offering protection, preventing cell death and promoting cell recovery. Although the majority of HSPs functions are exerted in the cytoplasm and organelles, several lines of evidence reveal that HSPs are able to induce cell responses in the extracellular milieu. HSPs do not possess secretion signal peptides, and their secretion was subject to widespread skepticism until the demonstration of the role of unconventional secretion forms such as exosomes. Secretion of HSPs may confer immune system modulation and be a cell-to-cell mediated form of increasing stress resistance. Thus, there is a wide potential for secreted HSPs in resistance of cancer therapy and in the development new therapeutic strategies. PMID:28468249

The heat shock response and major heat shock proteins of Tritrichomonas mobilensis and Tritrichomonas augusta.

PubMed

Bozner, P

1996-02-01

The responses to heat shock in Tritrichomonas mobilensis, a squirrel monkey parasite and Tritrichomonas augusta, an amphibian trichomonad, were evaluated by means of metabolic labeling with [35S]methionine. Electrophoretically separated trichomonad proteins synthesized at different temperatures were visualized by autoradiography and the label incorporation quantitated by a trichloroacetic acid precipitation procedure. A considerable difference in thermotolerance between the two species was found as the protein synthesis reached a maximum at 41 C in T. mobilensis and 37 C in T. augusta. The latter tolerated temperature increases 13 C above normal cultivation temperatures as compared to only 4 C thermotolerance range above normal in T. mobilensis. Major heat shock proteins (Hsps) were expressed in both T. mobilensis (with apparent Mr 94, 72, and 58 kDa) and T. augusta (Mr 94, 70, and 56 kDa) as revealed by autoradiography. Western blot analysis with polyclonal antibody against DnaK of Escherichia coli showed the presence of antigenic Hsp70 homologs in both trichomonads. Similarly, a polyclonal antibody against Hsp60 with broad interspecies cross-reactivity detected Hsp60 homologs in both T. mobilensis and T. augusta. The anti-DnaK antibody cross-reacted with a T. mobilensis protein localized in Golgi apparatus as demonstrated by immunoelectron microscopy. Immunocytochemistry on trichomonad frozen sections revealed the presence of the Hsp60 homolog in light-microscopic granules corresponding to hydrogenosomes.

RSK2 represses HSF1 activation during heat shock

PubMed Central

Wang, Xiaozhe; Asea, Alexzander; Xie, Yue; Kabingu, Edith; Stevenson, Mary Ann; Calderwood, Stuart K.

2000-01-01

Heat shock transcription factor 1(HSF1) activation is a multistep process. The conversion of a latent cytoplasmic form to a nuclear, DNA binding state appears to be activated by nonsteroidal anti-inflammatory drugs. In previous studies, we showed that HSF 1 is phosphorylated by the protein kinase RSK2 in vitro and that this effect is inhibited by nonsteroidal anti-inflammatory drugs at the concentration that leads to the activation of HSF1 in vivo (Stevenson et al 1999). In the present study, using cells from a patient with Coffin-Lowry syndrome (deficient in RSK2), we demonstrate that RSK2 slightly represses activation of HSF1 in vivo at 37°C. In Coffin-Lowry syndrome cells, HSF1-HSE DNA binding activity after treatment with sodium salicylate was slightly higher than that in untreated cells, indicating that although RSK2 is involved in HSF1 regulation, it is not the unique protein kinase that suppresses HSF1-HSE binding activity at 37°C. However, heat shock treatment resulted in significantly higher HSF1-HSE binding activity in Coffin-Lowry syndrome cells as compared with normal controls, suggesting that RSK2 represses HSF1-HSE binding activity during heat shock. PMID:11189448

RSK2 represses HSF1 activation during heat shock.

PubMed

Wang, X; Asea, A; Xie, Y; Kabingu, E; Stevenson, M A; Calderwood, S K

2000-11-01

Heat shock transcription factor 1(HSF1) activation is a multistep process. The conversion of a latent cytoplasmic form to a nuclear, DNA binding state appears to be activated by nonsteroidal anti-inflammatory drugs. In previous studies, we showed that HSF 1 is phosphorylated by the protein kinase RSK2 in vitro and that this effect is inhibited by nonsteroidal anti-inflammatory drugs at the concentration that leads to the activation of HSF1 in vivo (Stevenson et al 1999). In the present study, using cells from a patient with Coffin-Lowry syndrome (deficient in RSK2), we demonstrate that RSK2 slightly represses activation of HSF1 in vivo at 37 degrees C. In Coffin-Lowry syndrome cells, HSF1-HSE DNA binding activity after treatment with sodium salicylate was slightly higher than that in untreated cells, indicating that although RSK2 is involved in HSF1 regulation, it is not the unique protein kinase that suppresses HSF1-HSE binding activity at 37 degrees C. However, heat shock treatment resulted in significantly higher HSF1-HSE binding activity in Coffin-Lowry syndrome cells as compared with normal controls, suggesting that RSK2 represses HSF1-HSE binding activity during heat shock.

Experimental Study of Shock Wave Interference Heating on a Cylindrical Leading Edge. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Wieting, Allan R.

1987-01-01

An experimental study of shock wave interference heating on a cylindrical leading edge representative of the cowl of a rectangular hypersonic engine inlet at Mach numbers of 6.3, 6.5, and 8.0 is presented. Stream Reynolds numbers ranged from 0.5 x 106 to 4.9 x 106 per ft. and stream total temperature ranged from 2100 to 3400 R. The model consisted of a 3" dia. cylinder and a shock generation wedge articulated to angles of 10, 12.5, and 15 deg. A fundamental understanding was obtained of the fluid mechanics of shock wave interference induced flow impingement on a cylindrical leading edge and the attendant surface pressure and heat flux distributions. The first detailed heat transfer rate and pressure distributions for two dimensional shock wave interference on a cylinder was provided along with insight into the effects of specific heat variation with temperature on the phenomena. Results show that the flow around a body in hypersonic flow is altered significantly by the shock wave interference pattern that is created by an oblique shock wave from an external source intersecting the bow shock wave produced in front of the body.

Heat-shock inactivation of the TFIIH-associated kinase and change in the phosphorylation sites on the C-terminal domain of RNA polymerase II.

PubMed

Dubois, M F; Vincent, M; Vigneron, M; Adamczewski, J; Egly, J M; Bensaude, O

1997-02-15

The C-terminal domain (CTD) of the RNA polymerase II largest subunit (RPB1) plays a central role in transcription. The CTD is unphosphorylated when the polymerase assembles into a preinitiation complex of transcription and becomes heavily phosphorylated during promoter clearance and entry into elongation of transcription. A kinase associated to the general transcription factor TFIIH, in the preinitiation complex, phosphorylates the CTD. The TFIIH-associated CTD kinase activity was found to decrease in extracts from heat-shocked HeLa cells compared to unstressed cells. This loss of activity correlated with a decreased solubility of the TFIIH factor. The TFIIH-kinase impairment during heat-shock was accompanied by the disappearance of a particular phosphoepitope (CC-3) on the RPB1 subunit. The CC-3 epitope was localized on the C-terminal end of the CTD and generated in vitro when the RPB1 subunit was phosphorylated by the TFIIH-associated kinase but not by another CTD kinase such as MAP kinase. In apparent discrepancy, the overall RPB1 subunit phosphorylation increased during heat-shock. The decreased activity in vivo of the TFIIH kinase might be compensated by a stress-activated CTD kinase such as MAP kinase. These results also suggest that heat-shock gene transcription may have a weak requirement for TFIIH kinase activity.

Ectromelia virus upregulates the expression of heat shock protein 70 to promote viral replication.

PubMed

Cheng, Wenyu; Jia, Huaijie; Wang, Xiaoxia; He, Xiaobing; Jin, Qiwang; Cao, Jingxin; Jing, Zhizhong

2018-08-01

The ectromelia virus (ECTV) is a mouse specific Orthopoxvirus that causes lethal infection in some mouse strains. ECTV infection of these mouse strains has been used as a valuable model for understanding the interplay between Orthopoxvirus species and their hosts, including variola virus in humans. Although poxviruses encode numerous proteins required for DNA and RNA synthesis, and are less dependent on host functions than other DNA viruses, a detailed understanding of the host factors required for the replication of poxviruses is lacking. Heat shock protein 70 (Hsp70) isoforms have been reported to serve various roles in the replication cycle of numerous viruses. In the present study, microarray and reverse transcription‑quantitative polymerase chain reaction analysis were conducted to investigate the host gene expression profiles following ECTV infection in mice and cell cultures. The results indicated that one Hsp70 isoform, Hsp70 member 1B (Hspa1b), was highly upregulated during ECTV infection in vitro and in vivo. Subsequently, overexpression of Hspa1b protein and small interfering RNA‑mediated gene silencing of Hspa1b revealed that Hspa1b is required for efficient replication of ECTV. Furthermore, the results demonstrated that ECTV replication may be significantly suppressed by two chemical Hspa1b inhibitors: Quercetin and VER155008. In conclusion, the present study clearly demonstrated that ECTV infection upregulates the expression of Hspa1b in order to promote its replication. The dependence on Hsp70 may be used as a novel therapeutic target for the treatment of Orthopoxvirus infection.

Transcriptional regulation of heat shock proteins and ascorbate peroxidase by CtHsfA2b from African bermudagrass conferring heat tolerance in Arabidopsis

PubMed Central

Wang, Xiuyun; Huang, Wanlu; Yang, Zhimin; Liu, Jun; Huang, Bingru

2016-01-01

Heat stress transcription factor A2s (HsfA2s) are key regulators in plant response to high temperature. Our objectives were to isolate an HsfA2 gene (CtHsfA2b) from a warm-season grass species, African bermudagrass (Cynodon transvaalensis Burtt-Davy), and to determine the physiological functions and transcriptional regulation of HsfA2 for improving heat tolerance. Gene expression analysis revealed that CtHsfA2b was heat-inducible and exhibited rapid response to increasing temperature. Ectopic expression of CtHsfA2b improved heat tolerance in Arabidopsis and restored heat-sensitive defects of Arabidopsis hsfa2 mutant, which was demonstrated by higher survival rate and photosynthetic parameters, and lower electrolyte leakage in transgenic plants compared to the WT or hsfa2 mutant. CtHsfA2b transgenic plants showed elevated transcriptional regulation of several downstream genes, including those encoding ascorbate peroxidase (AtApx2) and heat shock proteins [AtHsp18.1-CI, AtHsp22.0-ER, AtHsp25.3-P and AtHsp26.5-P(r), AtHsp70b and AtHsp101-3]. CtHsfA2b was found to bind to the heat shock element (HSE) on the promoter of AtApx2 and enhanced transcriptional activity of AtApx2. These results suggested that CtHsfA2b could play positive roles in heat protection by up-regulating antioxidant defense and chaperoning mechanisms. CtHsfA2b has the potential to be used as a candidate gene to genetically modify cool-season species for improving heat tolerance. PMID:27320381

Heat shock factor 2 is required for maintaining proteostasis against febrile-range thermal stress and polyglutamine aggregation

PubMed Central

Shinkawa, Toyohide; Tan, Ke; Fujimoto, Mitsuaki; Hayashida, Naoki; Yamamoto, Kaoru; Takaki, Eiichi; Takii, Ryosuke; Prakasam, Ramachandran; Inouye, Sachiye; Mezger, Valerie; Nakai, Akira

2011-01-01

Heat shock response is characterized by the induction of heat shock proteins (HSPs), which facilitate protein folding, and non-HSP proteins with diverse functions, including protein degradation, and is regulated by heat shock factors (HSFs). HSF1 is a master regulator of HSP expression during heat shock in mammals, as is HSF3 in avians. HSF2 plays roles in development of the brain and reproductive organs. However, the fundamental roles of HSF2 in vertebrate cells have not been identified. Here we find that vertebrate HSF2 is activated during heat shock in the physiological range. HSF2 deficiency reduces threshold for chicken HSF3 or mouse HSF1 activation, resulting in increased HSP expression during mild heat shock. HSF2-null cells are more sensitive to sustained mild heat shock than wild-type cells, associated with the accumulation of ubiquitylated misfolded proteins. Furthermore, loss of HSF2 function increases the accumulation of aggregated polyglutamine protein and shortens the lifespan of R6/2 Huntington's disease mice, partly through αB-crystallin expression. These results identify HSF2 as a major regulator of proteostasis capacity against febrile-range thermal stress and suggest that HSF2 could be a promising therapeutic target for protein-misfolding diseases. PMID:21813737

Heat shock protein 10 (Hsp10) in immune-related diseases: one coin, two sides

PubMed Central

Jia, Haibo; Halilou, Amadou I.; Hu, Liang; Cai, Wenqian; Liu, Jing; Huang, Bo

2011-01-01

Heat shock protein 10 (Hsp10) in eukaryotes, originally identified as a mitochondrial chaperone, now is also known to be present in cytosol, cell surface, extracellular space and peripheral blood. Functionally besides participating in mitochondrial protein folding in association with Hsp60, Hsp10 appears to be related to pregnancy, cancer and autoimmune inhibition. Hsp10 can be released to peripheral blood at very early time point of pregnancy and given another name called early pregnancy factor (EPF), which seems to play a critical role in developing a pregnant niche. In malignant disorders, Hsp10 is usually abnormally expressed in the cytosol of malignant cells and further released to extracellular space, resulting in tumor-promoting effect from various aspects. Furthermore, distinct from other heat shock protein members, whose soluble form is recognized as danger signal by immune cells and triggers immune responses, Hsp10 after release, however, is designed to be an inhibitory signal by limiting immune response. This review discusses how Hsp10 participates in various physiological and pathological processes from basic protein molecule folding to pregnancy, cancer and autoimmune diseases, and emphasizes how important the location is for the function exertion of a molecule. PMID:21969171

Exposure of gnotobiotic Artemia franciscana larvae to abiotic stress promotes heat shock protein 70 synthesis and enhances resistance to pathogenic Vibrio campbellii

PubMed Central

Pineda, Carlos; MacRae, Thomas H.; Sorgeloos, Patrick; Bossier, Peter

2008-01-01

Larvae of the brine shrimp Artemia franciscana serve as important feed in fish and shellfish larviculture; however, they are subject to bacterial diseases that devastate entire populations and consequently hinder their use in aquaculture. Exposure to abiotic stress was shown previously to shield Artemia larvae against infection by pathogenic Vibrio, with the results suggesting a mechanistic role for heat shock protein 70. In the current report, combined hypothermic/hyperthermic shock followed by recovery at ambient temperature induced Hsp70 synthesis in Artemia larvae. Thermotolerance was also increased as was protection against infection by Vibrio campbellii, the latter indicated by reduced mortality and lower bacterial load in challenge tests. Resistance to Vibrio improved in the face of declining body mass as demonstrated by measurement of ash-free dry weight. Hypothermic stress only and acute osmotic insult did not promote Hsp70 expression and thermotolerance in Artemia larvae nor was resistance to Vibrio challenge augmented. The data support a causal link between Hsp70 accumulation induced by abiotic stress and enhanced resistance to infection by V. campbellii, perhaps via stimulation of the Artemia immune system. This possibility is now under investigation, and the work may reveal fundamental properties of crustacean immunity. Additionally, the findings are important in aquaculture where development of procedures to prevent bacterial infection of feed stock such as Artemia larvae is a priority. PMID:18347942

The Barley Powdery Mildew Candidate Secreted Effector Protein CSEP0105 Inhibits the Chaperone Activity of a Small Heat Shock Protein1[OPEN

PubMed Central

Ahmed, Ali Abdurehim; Pedersen, Carsten; Schultz-Larsen, Torsten; Kwaaitaal, Mark; Jørgensen, Hans Jørgen Lyngs; Thordal-Christensen, Hans

2015-01-01

Pathogens secrete effector proteins to establish a successful interaction with their host. Here, we describe two barley (Hordeum vulgare) powdery mildew candidate secreted effector proteins, CSEP0105 and CSEP0162, which contribute to pathogen success and appear to be required during or after haustorial formation. Silencing of either CSEP using host-induced gene silencing significantly reduced the fungal haustorial formation rate. Interestingly, both CSEPs interact with the barley small heat shock proteins, Hsp16.9 and Hsp17.5, in a yeast two-hybrid assay. Small heat shock proteins are known to stabilize several intracellular proteins, including defense-related signaling components, through their chaperone activity. CSEP0105 and CSEP0162 localized to the cytosol and the nucleus of barley epidermal cells, whereas Hsp16.9 and Hsp17.5 are cytosolic. Intriguingly, only those specific CSEPs changed localization and became restricted to the cytosol when coexpressed with Hsp16.9 and Hsp17.5, confirming the CSEP-small heat shock protein interaction. As predicted, Hsp16.9 showed chaperone activity, as it could prevent the aggregation of Escherichia coli proteins during thermal stress. Remarkably, CSEP0105 compromised this activity. These data suggest that CSEP0105 promotes virulence by interfering with the chaperone activity of a barley small heat shock protein essential for defense and stress responses. PMID:25770154

Antipsychotics promote GABAergic interneuron genesis in the adult rat brain: Role of heat-shock protein production.

PubMed

Kaneta, Hiroo; Ukai, Wataru; Tsujino, Hanako; Furuse, Kengo; Kigawa, Yoshiyasu; Tayama, Masaya; Ishii, Takao; Hashimoto, Eri; Kawanishi, Chiaki

2017-09-01

Current antipsychotics reduce positive symptoms and reverse negative symptoms in conjunction with cognitive behavioral issues with the goal of restoring impaired occupational and social functioning. However, limited information is available on their influence on gliogenesis or their neurogenic properties in adult schizophrenia brains, particularly on GABAergic interneuron production. In the present study, we used young adult subventricular zone (SVZ)-derived progenitor cells expressing proteoglycan NG2 cultures to examine the oligodendrocyte and GABAergic interneuron genesis effects of several kinds of antipsychotics on changes in differentiation function induced by exposure to the NMDA receptor antagonist MK-801. We herein demonstrated that antipsychotics promoted or restored changes in the oligodendrocyte/GABAergic interneuron differentiation functions of NG2(+) cells induced by the exposure to MK-801, which was considered to be one of the drug-induced schizophrenia model. We also demonstrated that antipsychotics restored heat-shock protein (HSP) production in NG2(+) cells with differentiation impairment. The antipsychotics olanzapine, aripiprazole, and blonanserin, but not haloperidol increased HSP90 levels, which were reduced by the exposure to MK-801. Our results showed that antipsychotics, particularly those recently synthesized, exerted similar GABAergic interneuron genesis effects on NG2(+) neuronal/glial progenitor cells in the adult rat brain by increasing cellular HSP production, and also suggest that HSP90 may play a crucial role in the pathophysiology of schizophrenia and is a key target for next drug development. Copyright © 2017 Elsevier Ltd. All rights reserved.

The role of heat shock proteins in kidney disease

PubMed Central

2016-01-01

Abstract Heat Shock Proteins (HSP) belong to the family of intracellular proteins that are constitutively expressed and are upregulated by various stressors including heat, oxidative and chemical stress. HSP helps in reparative processes, including the refolding of damaged proteins and the removal of irreparably damaged proteins that would initiate cellular death or apoptosis. A growing body of evidence has expanded the role of HSP and defined their role in diseases such as neurodegenerative disorders, cancer, ischemic heart disease and kidney diseases. The protective role of HSP in ischemic renal injury has been described and HSP impairment has been noted in other forms of kidney injuries including post-transplant situation. Further research into the role of HSP in prevention of kidney injury is crucial if translation from the laboratory to patient bedside has to occur. This article aims to be a review of heat shock protein, and its relevance to kidney diseases. PMID:28191532

Interference heating from interactions of shock waves with turbulent boundary layers at Mach 6

NASA Technical Reports Server (NTRS)

Johnson, C. B.; Kaufman, L. G., II

1974-01-01

An experimental investigation of interference heating resulting from interactions of shock waves and turbulent boundary layers was conducted. Pressure and heat-transfer distributions were measured on a flat plate in the free stream and on the wall of the test section of the Langley Mach 6 high Reynolds number tunnel for Reynolds numbers ranging from 2 million to 400 million. Various incident shock strengths were obtained by varying a wedge-shock generator angle (from 10 deg to 15 deg) and by placing a spherical-shock generator at different vertical positions above the instrumented flat plate and tunnel wall. The largest heating-rate amplification factors obtained for completely turbulent boundary layers were 22.1 for the flat plate and 11.6 for the tunnel wall experiments. Maximum heating correlated with peak pressures using a power law with a 0.85 exponent. Measured pressure distributions were compared with those calculated using turbulent free-interaction pressure rise theories, and separation lengths were compared with values calculated by using different methods.

Effect of wall heat transfer on shock-tube test temperature at long times

NASA Astrophysics Data System (ADS)

Frazier, C.; Lamnaouer, M.; Divo, E.; Kassab, A.; Petersen, E.

2011-02-01

When performing chemical kinetics experiments behind reflected shock waves at conditions of lower temperature (<1,000 K), longer test times on the order of 10-20 ms may be required. The integrity of the test temperature during such experiments may be in question, because heat loss to the tube walls may play a larger role than is generally seen in shock-tube kinetics experiments that are over within a millisecond or two. A series of detailed calculations was performed to estimate the effect of longer test times on the temperature uniformity of the post-shock test gas. Assuming the main mode of heat transfer is conduction between the high-temperature gas and the colder shock-tube walls, a comprehensive set of calculations covering a range of conditions including test temperatures between 800 and 1,800 K, pressures between 1 and 50 atm, driven-tube inner diameters between 3 and 16.2 cm, and test gases of N2 and Ar was performed. Based on the results, heat loss to the tube walls does not significantly reduce the area-averaged temperature behind the reflected shock wave for test conditions that are likely to be used in shock-tube studies for test times up to 20 ms (and higher), provided the shock-tube inner diameter is sufficiently large (>8cm). Smaller diameters on the order of 3 cm or less can experience significant temperature loss near the reflected-shock region. Although the area-averaged gas temperature decreases due to the heat loss, the main core region remains spatially uniform so that the zone of temperature change is limited to only the thermal layer adjacent to the walls. Although the heat conduction model assumes the gas and wall to behave as solid bodies, resulting in a core gas temperature that remains constant at the initial temperature, a two-zone gas model that accounts for density loss from the core to the colder thermal layer indicates that the core temperature and gas pressure both decrease slightly with time. A full CFD solution of the shock

Hormetic heat shock and HSF-1 overexpression improve C. elegans survival and proteostasis by inducing autophagy.

PubMed

Kumsta, Caroline; Hansen, Malene

2017-06-03

The cellular recycling process of macroautophagy/autophagy is an essential homeostatic system induced by various stresses, but it remains unclear how autophagy contributes to organismal stress resistance. In a recent study, we report that a mild and physiologically beneficial ("hormetic") heat shock as well as overexpression of the heat-shock responsive transcription factor HSF-1 systemically increases autophagy in C. elegans. Accordingly, we found HSF-1- and heat stress-inducible autophagy to be required for C. elegans thermoresistance and longevity. Moreover, a hormetic heat shock or HSF-1 overexpression alleviated PolyQ protein aggregation in an autophagy-dependent manner. Collectively, we demonstrate a critical role for autophagy in C. elegans stress resistance and hormesis, and reveal a requirement for autophagy in HSF-1 regulated functions in the heat-shock response, proteostasis, and aging.

Ion Thermalization and Electron Heating across Quasi-Perpendicular Shocks Observed by the MMS Mission

NASA Astrophysics Data System (ADS)

Chen, L.-J.; Wilson, L. B., III; Wang, S.; Bessho, N.; Viñas, A. F.-; Lai, H.; Russell, C. T.; Schwartz, S. J.; Hesse, M.; Moore, T. E.; Burch, J. L.; Gershman, D. J.; Giles, B. L.; Torbert, R. B.; Ergun, R. E.; Dorelli, J.; Strangeway, R. J.; Paterson, W. R.; Lavraud, B.; Khotyaintsev, Yu. V.

2017-12-01

Collisionless shocks often involve intense plasma heating in space and astrophysical systems. Despite decades of research, a number of key questions concerning electron and ion heating across collisionless shocks remain unanswered. We 'image' 20 supercritical quasi-perpendicular bow shocks encountered by the Magnetospheric Multiscale (MMS) spacecraft with electron and ion distribution functions to address how ions are thermalized and how electrons are heated. The continuous burst measurements of 3D plasma distribution functions from MMS reveal that the primary thermalization phase of ions occurs concurrently with the main temperature increase of electrons as well as large-amplitude wave fluctuations. Approaching the shock from upstream, the ion temperature (Ti) increases due to the reflected ions joining the incoming solar wind population, as recognized by prior studies, and the increase of Ti precedes that of the electrons. Thermalization in the form of merging between the decelerated solar wind ions and the reflected component often results in a decrease in Ti. In most cases, the Ti decrease is followed by a gradual increase further downstream. Anisotropic, energy-dependent, and/or nongyrotropic electron energization are observed in association with large electric field fluctuations in the main electron temperature (Te) gradient, motivating a renewed scrutiny of the effects from the electrostatic cross-shock potential and wave fluctuations on electron heating. Particle-in-cell (PIC) simulations are carried out to assist interpretations of the MMS observations. We assess the roles of instabilities and the cross-shock potential in thermalizing ions and heating electrons based on the MMS measurements and PIC simulation results. Challenges will be posted for future computational studies and laboratory experiments on collisionless shocks.

Ion Thermalization and Electron Heating across Quasi-Perpendicular Shocks Observed by the MMS Mission

NASA Astrophysics Data System (ADS)

Chen, L. J.; Wilson, L. B., III; Wang, S.; Bessho, N.; Figueroa-Vinas, A.; Lai, H.; Russell, C. T.; Schwartz, S. J.; Hesse, M.; Moore, T. E.; Burch, J.; Gershman, D. J.; Giles, B. L.; Torbert, R. B.; Ergun, R.; Dorelli, J.; Strangeway, R. J.; Paterson, W. R.; Lavraud, B.; Khotyaintsev, Y. V.

2017-12-01

Collisionless shocks often involve intense plasma heating in space and astrophysical systems. Despite decades of research, a number of key questions concerning electron and ion heating across collisionless shocks remain unanswered. We `image' 20 supercritical quasi-perpendicular bow shocks encountered by the Magnetospheric Multiscale (MMS) spacecraft with electron and ion distribution functions to address how ions are thermalized and how electrons are heated. The continuous burst measurements of 3D plasma distribution functions from MMS reveal that the primary thermalization phase of ions occurs concurrently with the main temperature increase of electrons as well as large-amplitude wave fluctuations. Approaching the shock from upstream, the ion temperature (Ti) increases due to the reflected ions joining the incoming solar wind population, as recognized by prior studies, and the increase of Ti precedes that of the electrons. Thermalization in the form of merging between the decelerated solar wind ions and the reflected component often results in a decrease in Ti. In most cases, the Ti decrease is followed by a gradual increase further downstream. Anisotropic, energy-dependent, and/or nongyrotropic electron energization are observed in association with large electric field fluctuations in the main electron temperature (Te) gradient, motivating a renewed scrutiny of the effects from the electrostatic cross-shock potential and wave fluctuations on electron heating. Particle-in-cell (PIC) simulations are carried out to assist interpretations of the MMS observations. We assess the roles of instabilities and the cross-shock potential in thermalizing ions and heating electrons based on the MMS measurements and PIC simulation results. Challenges will be posted for future computational studies and laboratory experiments on collisionless shocks.

Recombinant HSP70 and mild heat shock stimulate growth of aged mesenchymal stem cells.

PubMed

Andreeva, N V; Zatsepina, O G; Garbuz, D G; Evgen'ev, M B; Belyavsky, A V

2016-07-01

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.

Epigallocatechin-3-gallate suppressed the over-expression of HSP 70 and MDR1 induced by heat shock in SGC 7901.

PubMed

Tang, Xiao-Yan; Zhu, You-Qing

2008-06-01

This study investigated the effects of epigallocatechin-3-gallate (EGCG) on the expression of HSP 70 and MDR 1. SGC-7901 cells were cultured with RPMI 1640 medium. The single or combined effects of EGCG (0.1, 1, 10, 20, and 40 micromol/L) and heat shock were examined by MTT assay. The expression of HSP 70 and MDR 1 was semi-quantified by the reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry method (SP staining). EGCG suppressed cell proliferation at a time- and dose-dependent manner. The effects of combined treatment with EGCG and heat shock on the growth of SGC-7901 cells were stronger than single effects of EGCG. After using EGCG for 24 h, 48 h and 72 h, the IC50s were 112.5 micromol/l, 21.41 micromol/l and 5.24 micromol/l, respectively. Heat shock stimulated the over-expression of HSP 70, especially after heat shock for 8 h, as well as MDR1 after heat shock for 24 h. But EGCG suppressed the over-expression induced by heat shock. The authors conclude that EGCG inhibited the proliferation of SGC-7901, and EGCG combined with heat shock strengthened the effects. Heat shock weakened the over-expression of HSP 70 and MDR1; however, EGCG suppressed the over-expression of HSP 70 and MDR1 induced by heat shock. EGCG combined with heat shock may enhance the sensitivity of drugs to tumors.

Molecular and Physiological Analysis of a Heat-Shock Response in Wheat 1

PubMed Central

McElwain, Elizabeth F.; Spiker, Steven

1992-01-01

We have isolated two cDNA clones from wheat (Triticum aestivum L. var Stephens), designated WHSP16.8 and WHSP16.9, that are highly similar in sequence to the low molecular weight heat-shock protein genes previously isolated from soybean. RNA blot analysis confirms that these sequences are present in heat-shocked wheat seedlings, but not in control tissues. The WHSP16.8 and WHSP16.9 cDNAs were isolated by screening a lambda gt11 expression library with antibodies to HMGc (a chromosomal protein of wheat). Immunoblot analysis has demonstrated that the antibodies raised against HMGc also recognize a group of proteins that are induced by heat shock and have molecular weights (estimated by sodium dodecyl sulfate electrophoresis) consistent with the molecular weights of the proteins deduced from the sequences of the cDNAs. ImagesFigure 3Figure 4Figure 5 PMID:16669058

Mediator Recruitment to Heat Shock Genes Requires Dual Hsf1 Activation Domains and Mediator Tail Subunits Med15 and Med16*

PubMed Central

Kim, Sunyoung; Gross, David S.

2013-01-01

The evolutionarily conserved Mediator complex is central to the regulation of gene transcription in eukaryotes because it serves as a physical and functional interface between upstream regulators and the Pol II transcriptional machinery. Nonetheless, its role appears to be context-dependent, and the detailed mechanism by which it governs the expression of most genes remains unknown. Here we investigate Mediator involvement in HSP (heat shock protein) gene regulation in the yeast Saccharomyces cerevisiae. We find that in response to thermal upshift, subunits representative of each of the four Mediator modules (Head, Middle, Tail, and Kinase) are rapidly, robustly, and selectively recruited to the promoter regions of HSP genes. Their residence is transient, returning to near-background levels within 90 min. Hsf1 (heat shock factor 1) plays a central role in recruiting Mediator, as indicated by the fact that truncation of either its N- or C-terminal activation domain significantly reduces Mediator occupancy, whereas removal of both activation domains abolishes it. Likewise, ablation of either of two Mediator Tail subunits, Med15 or Med16, reduces Mediator recruitment to HSP promoters, whereas deletion of both abolishes it. Accompanying the loss of Mediator, recruitment of RNA polymerase II is substantially diminished. Interestingly, Mediator antagonizes Hsf1 occupancy of non-induced promoters yet facilitates enhanced Hsf1 association with activated ones. Collectively, our observations indicate that Hsf1, via its dual activation domains, recruits holo-Mediator to HSP promoters in response to acute heat stress through cooperative physical and/or functional interactions with the Tail module. PMID:23447536

Unrestrained AMPylation targets cytosolic chaperones and activates the heat shock response

PubMed Central

Truttmann, Matthias C.; Zheng, Xu; Hanke, Leo; Damon, Jadyn R.; Grootveld, Monique; Krakowiak, Joanna; Pincus, David; Ploegh, Hidde L.

2017-01-01

Protein AMPylation is a conserved posttranslational modification with emerging roles in endoplasmic reticulum homeostasis. However, the range of substrates and cell biological consequences of AMPylation remain poorly defined. We expressed human and Caenorhabditis elegans AMPylation enzymes—huntingtin yeast-interacting protein E (HYPE) and filamentation-induced by cyclic AMP (FIC)-1, respectively—in Saccharomyces cerevisiae, a eukaryote that lacks endogenous protein AMPylation. Expression of HYPE and FIC-1 in yeast induced a strong cytoplasmic Hsf1-mediated heat shock response, accompanied by attenuation of protein translation, massive protein aggregation, growth arrest, and lethality. Overexpression of Ssa2, a cytosolic heat shock protein (Hsp)70, was sufficient to partially rescue growth. In human cell lines, overexpression of active HYPE similarly induced protein aggregation and the HSF1-dependent heat shock response. Excessive AMPylation also abolished HSP70-dependent influenza virus replication. Our findings suggest a mode of Hsp70 inactivation by AMPylation and point toward a role for protein AMPylation in the regulation of cellular protein homeostasis beyond the endoplasmic reticulum. PMID:28031489

Chaos and ion heating in a slow shock

NASA Technical Reports Server (NTRS)

Lin, Y.; Lee, L. C.

1991-01-01

An ion heating mechanism is proposed of slow shocks, which is associated with the chaotic motion of particles in the downstream wave field. For a coherent electromagnetic wave propagating along the downstream magnetic field, corresponding to switch-off shocks, the particle motions are not chaotic. For an oblique wave, the interaction between the particles and the wave field may lead to chaotic particle motions. Such particles may be greatly thermalized within one wavelength after they are incident into the downstream wave field. The results can be used to explain the existence of the critical intermediate Mach number observed in the hybrid simulations.

Ste20-like kinase, SLK, activates the heat shock factor 1 - Hsp70 pathway.

PubMed

Cybulsky, Andrey V; Guillemette, Julie; Papillon, Joan

2016-09-01

Expression and activation of SLK increases during renal ischemia-reperfusion injury. When highly expressed, SLK signals via c-Jun N-terminal kinase and p38 to induce apoptosis, and it exacerbates apoptosis induced by ischemia-reperfusion injury. Overexpression of SLK in glomerular epithelial cells (GECs)/podocytes in vivo induces injury and proteinuria. In response to various stresses, cells enhance expression of chaperones or heat shock proteins (e.g. Hsp70), which are involved in the folding and maturation of newly synthesized proteins, and can refold denatured or misfolded proteins. We address the interaction of SLK with the heat shock factor 1 (HSF1)-Hsp70 pathway. Increased expression of SLK in GECs (following transfection) induced HSF1 transcriptional activity. Moreover, HSF1 transcriptional activity was increased by in vitro ischemia-reperfusion injury (chemical anoxia/recovery) and heat shock, and in both instances was amplified further by SLK overexpression. HSF1 binds to promoters of target genes, such as Hsp70 and induces their transcription. By analogy to HSF1, SLK stimulated Hsp70 expression. Hsp70 was also enhanced by anoxia/recovery and was further amplified by SLK overexpression. Induction of HSF1 and Hsp70 was dependent on the kinase activity of SLK, and was mediated via polo-like kinase-1. Transfection of constitutively active HSF1 enhanced Hsp70 expression and inhibited SLK-induced apoptosis. Conversely, the proapoptotic action of SLK was augmented by HSF1 shRNA, or the Hsp70 inhibitor, pifithrin-μ. In conclusion, increased expression/activity of SLK activates the HSF1-Hsp70 pathway. Hsp70 attenuates the primary proapoptotic effect of SLK. Modulation of chaperone expression may potentially be harnessed as cytoprotective therapy in renal cell injury. Copyright © 2016 Elsevier B.V. All rights reserved.

Heat-shock inactivation of the TFIIH-associated kinase and change in the phosphorylation sites on the C-terminal domain of RNA polymerase II.

PubMed Central

Dubois, M F; Vincent, M; Vigneron, M; Adamczewski, J; Egly, J M; Bensaude, O

1997-01-01

The C-terminal domain (CTD) of the RNA polymerase II largest subunit (RPB1) plays a central role in transcription. The CTD is unphosphorylated when the polymerase assembles into a preinitiation complex of transcription and becomes heavily phosphorylated during promoter clearance and entry into elongation of transcription. A kinase associated to the general transcription factor TFIIH, in the preinitiation complex, phosphorylates the CTD. The TFIIH-associated CTD kinase activity was found to decrease in extracts from heat-shocked HeLa cells compared to unstressed cells. This loss of activity correlated with a decreased solubility of the TFIIH factor. The TFIIH-kinase impairment during heat-shock was accompanied by the disappearance of a particular phosphoepitope (CC-3) on the RPB1 subunit. The CC-3 epitope was localized on the C-terminal end of the CTD and generated in vitro when the RPB1 subunit was phosphorylated by the TFIIH-associated kinase but not by another CTD kinase such as MAP kinase. In apparent discrepancy, the overall RPB1 subunit phosphorylation increased during heat-shock. The decreased activity in vivo of the TFIIH kinase might be compensated by a stress-activated CTD kinase such as MAP kinase. These results also suggest that heat-shock gene transcription may have a weak requirement for TFIIH kinase activity. PMID:9016617

Fish in hot water: hypoxaemia does not trigger catecholamine mobilization during heat shock in rainbow trout (Oncorhynchus mykiss).

PubMed

Currie, S; Ahmady, E; Watters, M A; Perry, S F; Gilmour, K M

2013-06-01

Rainbow trout (Oncorhynchus mykiss) exposed to an acute heat shock (1 h at 25 °C after raising water temperature from 13 °C to 25 °C over 4 h) mount a significant catecholamine response. The present study investigated the proximate mechanisms underlying catecholamine mobilization. Trout exposed to heat shock in vivo exhibited a significant reduction in arterial O(2) tension, but arterial O(2) concentration was not affected by heat shock, nor was catecholamine release during heat shock prevented by prior and concomitant exposure to hyperoxia (to prevent the fall in arterial O(2) tension). Thus, catecholamine mobilization probably was not triggered by impaired blood O(2) transport. Heat-shocked trout also exhibited an elevation of arterial CO(2) tension coupled with a fall in arterial pH, but these factors are not expected to trigger catecholamine release. The changes in blood O(2) and CO(2) tension occurred despite a significant hyperventilatory response to heat shock. Future studies should investigate whether catecholamine mobilization during heat shock in rainbow trout is triggered by a specific effect of high temperature activating the sympathetic nervous system via a thermosensitive transient receptor potential channel. Copyright © 2013 Elsevier Inc. All rights reserved.

Non-Lethal Heat Shock Increased Hsp70 and Immune Protein Transcripts but Not Vibrio Tolerance in the White-Leg Shrimp

PubMed Central

Loc, Nguyen Hong; MacRae, Thomas H.; Musa, Najiah; Bin Abdullah, Muhd Danish Daniel; Abdul Wahid, Mohd. Effendy; Sung, Yeong Yik

2013-01-01

Non-lethal heat shock boosts bacterial and viral disease tolerance in shrimp, possibly due to increases in endogenous heat shock protein 70 (Hsp70) and/or immune proteins. To further understand the mechanisms protecting shrimp against infection, Hsp70 and the mRNAs encoding the immune-related proteins prophenoloxidase (proPO), peroxinectin, penaeidin, crustin and hemocyanin were studied in post-larvae of the white-leg shrimp Litopenaeus vannamei, following a non-lethal heat shock. As indicated by RT-qPCR, a 30 min abrupt heat shock increased Hsp70 mRNA in comparison to non-heated animals. Immunoprobing of western blots and quantification by ELISA revealed that Hsp70 production after heat shock was correlated with enhanced Hsp70 mRNA. proPO and hemocyanin mRNA levels were augmented, whereas peroxinectin and crustin mRNA levels were unchanged following non-lethal heat shock. Penaeidin mRNA was decreased by all heat shock treatments. Thirty min abrupt heat shock failed to improve survival of post-larvae in a standardized challenge test with Vibrio harveyi, indicating that under the conditions of this study, L. vannamei tolerance to Vibrio infection was influenced neither by Hsp70 accumulation nor the changes in the immune-related proteins, observations dissimilar to other shrimp species examined. PMID:24039886

Effect of patchouli alcohol on the regulation of heat shock-induced oxidative stress in IEC-6 cells.

PubMed

Liu, Xiaoxi; Jiang, Linshu; Liu, Fenghua; Chen, Yuping; Xu, Lei; Li, Deyin; Ma, Yunfei; Li, Huanrong; Xu, Jianqin

2016-08-01

Purpose Patchouli alcohol (PA) is used to treat gastrointestinal dysfunction. The purpose of this study was to ascertain the function of PA in the regulated process of oxidative stress in rat intestinal epithelial cells (IEC-6). Materials and methods Oxidative stress was stimulated by exposing IEC-6 cells to heat shock (42 °C for 3 h). IEC-6 cells in treatment groups were pretreated with various concentrations of PA (10, 40, and 80 ng/mL) for 3 h before heat shock. Results Heat shock caused damage to the morphology of IEC-6 cells, and increased reactive oxygen species (ROS) level and malondialdehyde (MDA) content. Moreover, mRNA and protein expression by target genes related to oxidative stress in heat shock were also altered. Specifically, the mRNA expression by HSP70, HSP90, GSH-px, NRF2 nd HO-1were all increased, and Nrf2 and Keap1 protein expression were increased after heat shock. However, pretreatment with PA weakened the level of damage to the cellular morphology, and decreased the MDA content caused by heat shock, indicating PA had cytoprotective activities. Pretreatment with PA at high dose significantly increased generation of intracellular ROS. Compared with the heat shock group alone, PA pretreatment significantly decreased the mRNA expression by HSP70, HSP90, SOD, CAT, GSH-px, KEAP1 and HO-1. Furthermore, the high dose of PA significantly increased Nrf2 protein expression, while both the intermediate and high dose of PA significantly increased HO-1 protein expression. Conclusion Heat-shock-induced oxidative stress in IEC-6 cells, and PA could alleviate the Nrf2-Keap1 cellular oxidative stress responses.

Shock heating in numerical simulations of kink-unstable coronal loops

PubMed Central

Bareford, M. R.; Hood, A. W.

2015-01-01

An analysis of the importance of shock heating within coronal magnetic fields has hitherto been a neglected area of study. We present new results obtained from nonlinear magnetohydrodynamic simulations of straight coronal loops. This work shows how the energy released from the magnetic field, following an ideal instability, can be converted into thermal energy, thereby heating the solar corona. Fast dissipation of magnetic energy is necessary for coronal heating and this requirement is compatible with the time scales associated with ideal instabilities. Therefore, we choose an initial loop configuration that is susceptible to the fast-growing kink, an instability that is likely to be created by convectively driven vortices, occurring where the loop field intersects the photosphere (i.e. the loop footpoints). The large-scale deformation of the field caused by the kinking creates the conditions for the formation of strong current sheets and magnetic reconnection, which have previously been considered as sites of heating, under the assumption of an enhanced resistivity. However, our simulations indicate that slow mode shocks are the primary heating mechanism, since, as well as creating current sheets, magnetic reconnection also generates plasma flows that are faster than the slow magnetoacoustic wave speed. PMID:25897092

Proper Heat Shock Pretreatment Reduces Acute Liver Injury Induced by Carbon Tetrachloride and Accelerates Liver Repair in Mice

PubMed Central

Li, San-Qiang; Wang, Dong-Mei; Shu, You-Ju; Wan, Xue-Dong; Xu, Zheng-Shun; Li, En-Zhong

2013-01-01

Whether proper heat shock preconditioning can reduce liver injury and accelerate liver repair after acute liver injury is worth study. So mice received heat shock preconditioning at 40°C for 10 minutes (min), 20 min or 30 min and recovered at room temperature for 8 hours (h) under normal feeding conditions. Then acute liver injury was induced in the heat shock-pretreated mice and unheated control mice by intraperitoneal (i.p.) injection of carbon tetrachloride (CCl4). Hematoxylin and eosin (H&E) staining, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and the expression levels of heat shock protein 70 (HSP70), cytochrome P450 1A2 (CYP1A2) and proliferating cell nuclear antigen (PCNA) were detected in the unheated control mice and heat shock-pretreated mice after CCl4 administration. Our results showed that heat shock preconditioning at 40°C for 20 min remarkably improved the mice’s survival rate (P<0.05), lowered the levels of serum AST and ALT (P<0.05), induced HSP70 (P<0.01), CYP1A2 (P<0.01) and PCNA (P<0.05) expression, effectively reduced liver injury (P<0.05) and accelerated the liver repair (P<0.05) compared with heat shock preconditioning at 40°C for 10 min or 30 min in the mice after acute liver injury induced by CCl4 when compared with the control mice. Our results may be helpful in further investigation of heat shock pretreatment as a potential clinical approach to target liver injury PMID:24526809

SPERM MOTILITY IN HSF1 KNOCKOUT MICE AFTER HEAT SHOCK IS ASSOCIATED WITH FERTILITY DEFICITS

EPA Science Inventory

SPERM MOTILITY IN HSF1 KNOCKOUT MICE AFTER HEAT SHOCK IS ASSOCIATED WITH FERTILITY DEFICITS. L.F. Strader*, S.D. Perreault, J.C. Luft*, and D.J. Dix*. US EPA/ORD, Reproductive Toxicology Div., Research Triangle Park, NC
Heat shock proteins (HSPs) protect cells from environm...

Prediction and measurement of heat transfer rates for the shock-induced unsteady laminar boundary layer on a flat plate

NASA Technical Reports Server (NTRS)

Cook, W. J.

1972-01-01

The unsteady laminar boundary layer induced by the flow-initiating shock wave passing over a flat plate mounted in a shock tube was theoretically and experimentally studied in terms of heat transfer rates to the plate for shock speeds ranging from 1.695 to 7.34 km/sec. The theory presented by Cook and Chapman for the shock-induced unsteady boundary layer on a plate is reviewed with emphasis on unsteady heat transfer. A method of measuring time-dependent heat-transfer rates using thin-film heat-flux gages and an associated data reduction technique are outlined in detail. Particular consideration is given to heat-flux measurement in short-duration ionized shocktube flows. Experimental unsteady plate heat transfer rates obtained in both air and nitrogen using thin-film heat-flux gages generally agree well with theoretical predictions. The experimental results indicate that the theory continues to predict the unsteady boundary layer behavior after the shock wave leaves the trailing edge of the plate even though the theory is strictly applicable only for the time interval in which the shock remains on the plate.

The Effects of Calcitonin on the Development of and Ca2+ Levels in Heat-shocked Bovine Preimplantation Embryos In Vitro

PubMed Central

KAMANO, Shumpei; IKEDA, Shuntaro; SUGIMOTO, Miki; KUME, Shinichi

2014-01-01

Intracellular calcium homeostasis is essential for proper cell function. We investigated the effects of heat shock on the development of and the intracellular Ca2+ levels in bovine preimplantation embryos in vitro and the effects of calcitonin (CT), a receptor-mediated Ca2+ regulator, on heat shock-induced events. Heat shock (40.5 C for 10 h between 20 and 30 h postinsemination) of in vitro-produced bovine embryos did not affect the cleavage rate; however, it significantly decreased the rates of development to the 5- to 8-cell and blastocyst stages as compared with those of the control cultured for the entire period at 38.5 C (P < 0.05). The relative intracellular Ca2+ levels at the 1-cell stage (5 h after the start of heat shock), as assessed by Fluo-8 AM, a fluorescent probe for Ca2+, indicated that heat shock significantly lowered the Ca2+ level as compared with the control level. Semiquantitative reverse transcription PCR and western blot analyses revealed the expression of CT receptor in bovine preimplantation embryos. The addition of CT (10 nM) to the culture medium ameliorated the heat shock-induced impairment of embryonic development beyond the 5- to 8-cell stage. The Ca2+ level in the heat-shocked embryos cultured with CT was similar to that of the control embryos, suggesting that heat shock lowers the Ca2+ level in fertilized embryos in vitro and that a lower Ca2+ level is implicated in heat shock-induced impairment of embryonic development. Intracellular Ca2+-mobilizing agents, e.g., CT, may effectively circumvent the detrimental effects of heat shock on early embryonic development. PMID:24899099

Self similar flow behind an exponential shock wave in a self-gravitating, rotating, axisymmetric dusty gas with heat conduction and radiation heat flux

NASA Astrophysics Data System (ADS)

Bajargaan, Ruchi; Patel, Arvind

2018-04-01

One-dimensional unsteady adiabatic flow behind an exponential shock wave propagating in a self-gravitating, rotating, axisymmetric dusty gas with heat conduction and radiation heat flux, which has exponentially varying azimuthal and axial fluid velocities, is investigated. The shock wave is driven out by a piston moving with time according to an exponential law. The dusty gas is taken to be a mixture of a non-ideal gas and small solid particles. The density of the ambient medium is assumed to be constant. The equilibrium flow conditions are maintained and energy is varying exponentially, which is continuously supplied by the piston. The heat conduction is expressed in the terms of Fourier's law, and the radiation is assumed of diffusion type for an optically thick grey gas model. The thermal conductivity and the absorption coefficient are assumed to vary with temperature and density according to a power law. The effects of the variation of heat transfer parameters, gravitation parameter and dusty gas parameters on the shock strength, the distance between the piston and the shock front, and on the flow variables are studied out in detail. It is interesting to note that the similarity solution exists under the constant initial angular velocity, and the shock strength is independent from the self gravitation, heat conduction and radiation heat flux.

Heat shock protein 70 from a thermotolerant Diptera species provides higher thermoresistance to Drosophila larvae than correspondent endogenous gene.

PubMed

Shilova, V Y; Zatsepina, O G; Garbuz, D G; Funikov, S Y; Zelentsova, E S; Schostak, N G; Kulikov, A M; Evgen'ev, M B

2018-02-01

Heat shock proteins (Hsp70s) from two Diptera species that drastically differ in their heat shock response and longevity were investigated. Drosophila melanogaster is characterized by the absence of Hsp70 and other hsps under normal conditions and the dramatic induction of hsp synthesis after temperature elevation. The other Diptera species examined belongs to the Stratiomyidae family (Stratiomys singularior) and exhibits high levels of inducible Hsp70 under normal conditions coupled with a thermotolerant phenotype and much longer lifespan. To evaluate the impact of hsp70 genes on thermotolerance and longevity, we made use of a D. melanogaster strain that lacks all hsp70 genes. We introduced single copies of either S. singularior or D. melanogaster hsp70 into this strain and monitored the obtained transgenic flies in terms of thermotolerance and longevity. We developed transgenic strains containing the S. singularior hsp70 gene under control of a D. melanogaster hsp70 promoter. Although these adult flies did synthesize the corresponding mRNA after heat shock, they were not superior to the flies containing a single copy of D. melanogaster hsp70 in thermotolerance and longevity. By contrast, Stratiomyidae Hsp70 provided significantly higher thermotolerance at the larval stage in comparison with endogenous Hsp70. © 2017 The Royal Entomological Society.

Genetic variation in resistance of the preimplantation bovine embryo to heat shock.

PubMed

Hansen, Peter J

2014-12-01

Reproduction is among the physiological functions in mammals most susceptible to disruption by hyperthermia. Many of the effects of heat stress on function of the oocyte and embryo involve direct effects of elevated temperature (i.e. heat shock) on cellular function. Mammals limit the effects of heat shock by tightly regulating body temperature. This ability is genetically controlled: lines of domestic animals have been developed with superior ability to regulate body temperature during heat stress. Through experimentation in cattle, it is also evident that there is genetic variation in the resistance of cells to the deleterious effects of elevated temperature. Several breeds that were developed in hot climates, including Bos indicus (Brahman, Gir, Nelore and Sahiwal) and Bos taurus (Romosinuano and Senepol) are more resistant to the effects of elevated temperature on cellular function than breeds that evolved in cooler climates (Angus, Holstein and Jersey). Genetic differences are expressed in the preimplantation embryo by Day 4-5 of development (after embryonic genome activation). It is not clear whether genetic differences are expressed in cells in which transcription is repressed (oocytes >100 µm in diameter or embryos at stages before embryonic genome activation). The molecular basis for cellular thermotolerance has also not been established, although there is some suggestion for involvement of heat shock protein 90 and the insulin-like growth factor 1 system. Given the availability of genomic tools for genetic selection, identification of genes controlling cellular resistance to elevated temperature could be followed by progress in selection for those genes within the populations in which they exist. It could also be possible to introduce genes from thermotolerant breeds into thermally sensitive breeds. The ability to edit the genome makes it possible to design new genes that confer protection of cells from stresses like heat shock.

Characterization of heat shock cognate protein 70 gene and its differential expression in response to thermal stress between two wing morphs of Nilaparvata lugens (Stål).

PubMed

Lu, Kai; Chen, Xia; Liu, Wenting; Zhou, Qiang

2016-09-01

Previous studies have demonstrated differences in thermotolerance between two wing morphs of Nilaparvata lugens, the most serious pest of rice across the Asia. To reveal the molecular regulatory mechanisms underlying the differential thermal resistance abilities between two wing morphs, a full-length of transcript encoding heat shock cognate protein 70 (Hsc70) was cloned, and its expression patterns across temperature gradients were analyzed. The results showed that the expression levels of NlHsc70 in macropters increased dramatically after heat shock from 32 to 38°C, while NlHsc70 transcripts in brachypters remained constant under different temperature stress conditions. In addition, NlHsc70 expression in the macropters was significantly higher than that in brachypters at 1 and 2h recovery from 40°C heat shock. There was no significant difference in NlHsc70 mRNA expression between brachypters and macropters under cold shock conditions. Therefore, NlHsc70 was indeed a constitutively expressed member of the Hsp70 family in brachypters of N. lugens, while it was heat-inducible in macropters. Furthermore, the survival rates of both morphs injected with NlHsc70 dsRNA were significantly decreased following heat shock at 40°C or cold shock at 0°C for 1h. These results suggested that the up-regulation of NlHsc70 is possibly related to the thermal resistance, and the more effective inducement expression of NlHsc70 in macropters promotes a greater thermal tolerance under temperature stress conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

The role of heat shock proteins in protection and pathophysiology of the arterial wall.

PubMed

Xu, Q; Wick, G

1996-09-01

The arterial wall is an integrated functional component of the circulatory system that is continually remodelling in response to various stressors, including localized injury, toxins, smoking and hypercholesterolaemia. These stimuli directly or indirectly cause changes in blood pressure and damage to the vessel wall, and eventually induce arterial stiffness and obstruction. To maintain the homeostasis of the vessel wall, the vascular cells produce a high level of stress proteins, also known as heat shock proteins, which protect against damage during haemodynamic stress. However, an immune reaction to heat shock proteins might contribute to the development of atherosclerosis. We hypothesize that the induction of heat shock proteins is beneficial in the arterial wall's response to stress but is harmful in certain other circumstances.

Antarctic marine molluscs do have an HSP70 heat shock response

PubMed Central

Fraser, Keiron P. P.; Peck, Lloyd S.

2008-01-01

The success of any organism depends not only on niche adaptation but also the ability to survive environmental perturbation from homeostasis, a situation generically described as stress. Although species-specific mechanisms to combat “stress” have been described, the production of heat shock proteins (HSPs), such as HSP70, is universally described across all taxa. Members of the HSP70 gene family comprising the constitutive (HSC70) and inducible (HSP70) members, plus GRP78 (glucose-regulated protein, 78 kDa), a related HSP70 family member, were cloned using degenerate polymerase chain reaction (PCR) from two evolutionary divergent Antarctic marine molluscs (Laternula elliptica and Nacella concinna), a bivalve and a gastropod, respectively. The expression of the HSP70 family members was surveyed via quantitative PCR after an acute 2-h heat shock experiment. Both species demonstrated significant up-regulation of HSP70 gene expression in response to increased temperatures. However, the temperature level at which these responses were induced varied with the species (+6–8°C for L. elliptica and +8–10°C for N. concinna) compared to their natural environmental temperature). L. elliptica also showed tissue-specific expression of the genes under study. Previous work on Antarctic fish has shown that they lack the classical heat shock response, with the inducible form of HSP70 being permanently expressed with an expression not further induced under higher temperature regimes. This study shows that this is not the case for other Antarctic animals, with the two molluscs showing an inducible heat shock response, at a level probably set during their temperate evolutionary past. PMID:18347940

Antarctic marine molluscs do have an HSP70 heat shock response.

PubMed

Clark, Melody S; Fraser, Keiron P P; Peck, Lloyd S

2008-01-01

The success of any organism depends not only on niche adaptation but also the ability to survive environmental perturbation from homeostasis, a situation generically described as stress. Although species-specific mechanisms to combat "stress" have been described, the production of heat shock proteins (HSPs), such as HSP70, is universally described across all taxa. Members of the HSP70 gene family comprising the constitutive (HSC70) and inducible (HSP70) members, plus GRP78 (glucose-regulated protein, 78 kDa), a related HSP70 family member, were cloned using degenerate polymerase chain reaction (PCR) from two evolutionary divergent Antarctic marine molluscs (Laternula elliptica and Nacella concinna), a bivalve and a gastropod, respectively. The expression of the HSP70 family members was surveyed via quantitative PCR after an acute 2-h heat shock experiment. Both species demonstrated significant up-regulation of HSP70 gene expression in response to increased temperatures. However, the temperature level at which these responses were induced varied with the species (+6-8 degrees C for L. elliptica and +8-10 degrees C for N. concinna) compared to their natural environmental temperature). L. elliptica also showed tissue-specific expression of the genes under study. Previous work on Antarctic fish has shown that they lack the classical heat shock response, with the inducible form of HSP70 being permanently expressed with an expression not further induced under higher temperature regimes. This study shows that this is not the case for other Antarctic animals, with the two molluscs showing an inducible heat shock response, at a level probably set during their temperate evolutionary past.

Temporal patterns of cardiac performance and genes encoding heat shock proteins and metabolic sensors of an intertidal limpet Cellana toreuma during sublethal heat stress.

PubMed

Zhang, Shu; Han, Guo-dong; Dong, Yun-wei

2014-04-01

Intertidal invertebrates develop effective physiological adaptations to cope with the rapidly changing thermal environment in the intertidal zone. In the present study, the temporal patterns of heart rate, protein carbonyl groups, and genes encoding heat shock proteins (hsp70 and hsp90) and metabolic sensors (ampkα, ampkβ and sirt1) were measured to study the effect of sublethal heat stress on the cardiac function, oxidative stress, heat shock response and cellular metabolism of an intertidal limpet Cellana toreuma. All the physiological parameters are sensitive to temperature and duration of heat stress. Spearman correlation analysis revealed that the correlations between heart rate and levels of heat shock proteins mRNA and metabolic sensors mRNA were statistically significant. These results further suggest that cardiac function plays crucial roles in cellular energy metabolism and heat shock responses. The significant increase of protein carbonyl groups at 34°C after 4h exposure indicated that the failure of cardiac function and the increase of anaerobic metabolism partly leads to the increase of protein carbonyl groups. Generally, the physiological responses to heat stress are sensitive to temperature and are energy-consumptive, as indicated by the upregulation of metabolic sensors mRNA. However, the upregulation of heat shock proteins and metabolic sensors at the post-transcriptional level and related functions need to be confirmed in further experiments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Genomic organization of the Neurospora crassa gsn gene: possible involvement of the STRE and HSE elements in the modulation of transcription during heat shock.

PubMed

Freitas, F Zanolli; Bertolini, M C

2004-12-01

Glycogen synthase, an enzyme involved in glycogen biosynthesis, is regulated by phosphorylation and by the allosteric ligand glucose-6-phosphate (G6P). In addition, enzyme levels can be regulated by changes in gene expression. We recently cloned a cDNA for glycogen synthase ( gsn) from Neurospora crassa, and showed that gsn transcription decreased when cells were exposed to heat shock (shifted from 30 degrees C to 45 degrees C). In order to understand the mechanisms that control gsn expression, we isolated the gene, including its 5' and 3' flanking regions, from the genome of N. crassa. An ORF of approximately 2.4 kb was identified, which is interrupted by four small introns (II-V). Intron I (482 bp) is located in the 5'UTR region. Three putative Transcription Initiation Sites (TISs) were mapped, one of which lies downstream of a canonical TATA-box sequence (5'-TGTATAAA-3'). Analysis of the 5'-flanking region revealed the presence of putative transcription factor-binding sites, including Heat Shock Elements (HSEs) and STress Responsive Elements (STREs). The possible involvement of these motifs in the negative regulation of gsn transcription was investigated using Electrophoretic Mobility Shift Assays (EMSA) with nuclear extracts of N. crassa mycelium obtained before and after heat shock, and DNA fragments encompassing HSE and STRE elements from the 5'-flanking region. While elements within the promoter region are involved in transcription under heat shock, elements in the 5'UTR intron may participate in transcription during vegetative growth. The results thus suggest that N. crassa possesses trans -acting elements that interact with the 5'-flanking region to regulate gsn transcription during heat shock and vegetative growth.

Corequake and shock heating model of the 5 March 1979 gamma ray burst

NASA Technical Reports Server (NTRS)

Ellison, D. C.; Kazanas, D.

1983-01-01

Ramatry, et al. proposed a model to account for the 5 March 1979 gamma ray burst in terms of a neutron star corequake and subsequent shock heating of the neutron star atmosphere. This model is extended by examining the overall energetics and characteristics of these shocks, taking into account the e(+)-e(-) pair production behind the shock. The effects of a dipole magnetic field in the shock jump conditions are also examined and it is concluded that the uneven heating produced by such a field can account for the temperature difference between pole and equator implied by the pulsating phase of the burst. The overall energetics and distribution of energy between e(+)-(-) pairs and photons appears to be in agreement with observations if this event is at a distance of 55 kpc as implied by its association with the Large Magellanic Cloud.

The 60 kDa heat shock proteins in the hyperthermophilic archaeon Sulfolobus shibatae.

PubMed

Kagawa, H K; Osipiuk, J; Maltsev, N; Overbeek, R; Quaite-Randall, E; Joachimiak, A; Trent, J D

1995-11-10

One of the most abundant proteins in the hyperthermophilic archaeon Sulfolobus shibatae is the 59 kDa heat shock protein (TF55) that is believed to form a homo-oligomeric double ring complex structurally similar to the bacterial chaperonins. We discovered a second protein subunit in the S. shibatae ring complex (referred to as alpha) that is stoichiometric with TF55 (renamed beta). The gene and flanking regions of alpha were cloned and sequenced and its inferred amino acid sequence has 54.4% identity and 74.4% similarity to beta. Transcription start sites for both alpha and beta were mapped and three potential transcription regulatory regions were identified. Northern analyses of cultures shifted from normal growth temperatures (70 to 75 degrees C) to heat shock temperatures (85 to 90 degrees C) indicated that the levels of alpha and beta mRNAs increased during heat shock, but at all temperatures their relative proportions remained constant. Monitoring protein synthesis by autoradiography of total proteins from cultures pulse labeled with L(-)[35S]methionine at normal and heat shock temperatures indicated significant increases in alpha and beta synthesis during heat shock. Under extreme heat shock conditions (> or = 90 degrees C) alpha and beta appeared to be the only two proteins synthesized. The purified alpha and beta subunits combined to form high molecular mass complexes with similar mobilities on native polyacrylamide gels to the complexes isolated directly from cells. Equal proportions of the two subunits gave the greatest yield of the complex, which we refer to as a "rosettasome". It is argued that the rosettasome consists of two homo-oligomeric rings; one of alpha and the other of beta. Polyclonal antibodies against alpha and beta from S. shibatae cross-reacted with proteins of similar molecular mass in 10 out of the 17 archaeal species tested, suggesting that the two rosettasome proteins are highly conserved among the archaea. The archaeal sequences were

Wind Observations of Wave Heating and/or Particle Energization at Supercritical Interplanetary Shocks

NASA Technical Reports Server (NTRS)

Wilson, Lynn Bruce, III; Szabo, Adam; Koval, Andriy; Cattell, Cynthia A.; Kellogg, Paul J.; Goetz, Keith; Breneman, Aaron; Kersten, Kris; Kasper, Justin C.; Pulupa, Marc

2011-01-01

We present the first observations at supercritical interplanetary shocks of large amplitude (> 100 mV/m pk-pk) solitary waves, approx.30 mV/m pk-pk waves exhibiting characteristics consistent with electron Bernstein waves, and > 20 nT pk-pk electromagnetic lower hybrid-like waves, with simultaneous evidence for wave heating and particle energization. The solitary waves and the Bernstein-like waves were likely due to instabilities driven by the free energy provided by reflected ions [Wilson III et al., 2010]. They were associated with strong particle heating in both the electrons and ions. We also show a case example of parallel electron energization and perpendicular ion heating due to a electromagnetic lower hybrid-like wave. Both studies provide the first experimental evidence of wave heating and/or particle energization at interplanetary shocks. Our experimental results, together with the results of recent Vlasov [Petkaki and Freeman, 2008] and PIC [Matsukyo and Scholer, 2006] simulations using realistic mass ratios provide new evidence to suggest that the importance of wave-particle dissipation at shocks may be greater than previously thought.

Two novel heat shock genes encoding proteins produced in response to heterologous protein expression in Escherichia coli.

PubMed Central

Allen, S P; Polazzi, J O; Gierse, J K; Easton, A M

1992-01-01

In Escherichia coli high-level production of some heterologous proteins (specifically, human prorenin, renin, and bovine insulin-like growth factor 2) resulted in the induction of two new E. coli heat shock proteins, both of which have molecular masses of 16 kDa and are tightly associated with inclusion bodies formed during heterologous protein production. We named these inclusion body-associated proteins IbpA and IbpB. The coding sequences for IbpA and IbpB were identified and isolated from the Kohara E. coli gene bank. The genes for these proteins (ibpA and ibpB) are located at 82.5 min on the chromosome. Nucleotide sequencing of the two genes revealed that they are transcribed in the same direction and are separated by 110 bp. Putative Shine-Dalgarno sequences are located upstream from the initiation codons of both genes. A putative heat shock promoter is located upstream from ibpA, and a putative transcription terminator is located downstream from ibpB. A temperature upshift experiment in which we used a wild-type E. coli strain and an isogenic rpoH mutant strain indicated that a sigma 32-containing RNA polymerase is involved in the regulation of expression of these genes. There is 57.5% identity between the genes at the nucleotide level and 52.2% identity at the amino acid level. A search of the protein data bases showed that both of these 16-kDa proteins exhibit low levels of homology to low-molecular-weight heat shock proteins from eukaryotic species. Images PMID:1356969

Regulation of protein turnover by heat shock proteins.

PubMed

Bozaykut, Perinur; Ozer, Nesrin Kartal; Karademir, Betul

2014-12-01

Protein turnover reflects the balance between synthesis and degradation of proteins, and it is a crucial process for the maintenance of the cellular protein pool. The folding of proteins, refolding of misfolded proteins, and also degradation of misfolded and damaged proteins are involved in the protein quality control (PQC) system. Correct protein folding and degradation are controlled by many different factors, one of the most important of which is the heat shock protein family. Heat shock proteins (HSPs) are in the class of molecular chaperones, which may prevent the inappropriate interaction of proteins and induce correct folding. On the other hand, these proteins play significant roles in the degradation pathways, including endoplasmic reticulum-associated degradation (ERAD), the ubiquitin-proteasome system, and autophagy. This review focuses on the emerging role of HSPs in the regulation of protein turnover; the effects of HSPs on the degradation machineries ERAD, autophagy, and proteasome; as well as the role of posttranslational modifications in the PQC system. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of heat shocks on microbial community structure and microbial activity of a methanogenic enrichment degrading benzoate.

PubMed

Mei, R; Narihiro, T; Nobu, M K; Liu, W-T

2016-11-01

In anaerobic digesters, temperature fluctuation could lead to process instability and failure. It is still not well understood how digester microbiota as a whole respond to heat shock, and what specific organisms are vulnerable to perturbation or responsible for process recovery after perturbation. To address these questions, a mesophilic benzoate-degrading methanogenic culture enriched from digester was subjected to different levels of heat shock. Three types of methane production profiles after perturbation were observed in comparison to the control: uninhibited, inhibited with later recovery, and inhibited without recovery. These responses were correlated with the microbial community compositions based on the analyses of 16S rRNA and 16S rRNA gene. Specifically, the primary benzoate-degrading syntroph was highly affected by heat shock, and its abundance and activity were both crucial to the restoration of benzoate degradation after heat shock. In contrast, methanogens were stable regardless whether methane production was inhibited. Populations related to 'Candidatus Cloacimonetes' and Firmicutes showed stimulated growth. These observations indicated distinct physiological traits and ecological niches associated with individual microbial groups. The results obtained after exposure to heat shock can be critical to more comprehensive characterization of digester ecology under perturbations. Anaerobic digestion is an essential step in municipal wastewater treatment owing to its striking capacity of reducing wasted sludge and recovering energy. However, as an elaborate microbial process, it requires constant temperature control and is sensitive to heat shock. In this study, we explored the microbial response to heat shock of a methanogenic culture enriched from anaerobic digester sludge. Microorganisms that were vulnerable to perturbation or responsible for process recovery after perturbation were identified. © 2016 The Society for Applied Microbiology.

Al 1s-2p Absorption Spectroscopy of Shock-Wave Heating and Compression in Laser-Driven Planar Foil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sawada, H.; Regan, S.P.; Radha, P.B.

Time-resolved Al 1s-2p absorption spectroscopy is used to diagnose direct-drive, shock-wave heating and compression of planar targets having nearly Fermi-degenerate plasma conditions (Te ~ 10–40 eV, rho ~ 3–11 g/cm^3) on the OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. A planar plastic foil with a buried Al tracer layer was irradiated with peak intensities of 10^14–10^15 W/cm^2 and probed with the pseudocontinuum M-band emission from a point-source Sm backlighter in the range of 1.4–1.7 keV. The laser ablation process launches 10–70 Mbar shock waves into the CH/Al/CH target. The Al 1s-2p absorption spectra weremore » analyzed using the atomic physic code PRISMSPECT to infer Te and rho in the Al layer, assuming uniform plasma conditions during shock-wave heating, and to determine when the heat front penetrated the Al layer. The drive foils were simulated with the one-dimensional hydrodynamics code LILAC using a flux-limited (f =0.06 and f =0.1) and nonlocal thermal-transport model [V. N. Goncharov et al., Phys. Plasmas 13, 012702 (2006)]. The predictions of simulated shock-wave heating and the timing of heat-front penetration are compared to the observations. The experimental results for a wide variety of laser-drive conditions and buried depths have shown that the LILAC predictions using f = 0.06 and the nonlocal model accurately model the shock-wave heating and timing of the heat-front penetration while the shock is transiting the target. The observed discrepancy between the measured and simulated shock-wave heating at late times of the drive can be explained by the reduced radiative heating due to lateral heat flow in the corona.« less

Heat shock protein 70 as a biomarker of heat stress in a simulated hot cockpit.

PubMed

Kumar, Yadunanda; Chawla, Anuj; Tatu, Utpal

2003-07-01

Fighter pilots are frequently exposed to high temperatures during high-speed low-level flight. Heat strain can result in temporary impairment of cognitive functions and when severe, loss of consciousness and consequent loss of life and equipment. Induction of stress proteins is a highly conserved stress response mechanism from bacteria to humans. Induced stress protein levels are known to be cytoprotective and have been correlated with stress tolerance. Although many studies on the heat shock response mechanisms have been performed in cell culture and animal model systems, there is very limited information on stress protein induction in human subjects. Heat shock proteins (Hsp), especially Hsp70, may be induced in human subjects exposed to high temperatures in a hot cockpit designed to simulate heat stress experienced in low flying sorties. Six healthy volunteers were subjected to heat stress at 55 degrees C in a high temperature cockpit simulator for a period of 1 h at 30% humidity. Physiological parameters such as oral and skin temperatures, heart rate, and sweat rate were monitored regularly during this time. The level of Hsp70 in leukocytes was examined before and after the heat exposure in each subject. Hsp70 was found to be significantly induced in all the six subjects exposed to heat stress. The level of induced Hsp70 appears to correlate with other strain indicators such as accumulative circulatory strain and Craig's modified index. The usefulness of Hsp70 as a molecular marker of heat stress in humans is discussed.

[Triptolide reverses apatinib resistance in gastric cancer cell line MKN45 via inhibition of heat shock protein 70].

PubMed

Teng, F; Xu, Z Y; Lyu, H; Wang, Y P; Wang, L J; Huang, T; Sun, J C; Zhu, H T; Ni, Y X; Cheng, X D

2018-02-23

Objective: To investigate the effect of triptolide, a specific inhibitor of heat shock protein 70 (HSP70), on apatinib resistance in gastric cancer cells line MKN45. Methods: The apatinib-resistant cells (MKN45/AR) and MKN45 parental cells were treated with apatinib, triptolide and apatinib combined with triptolide, respectively. CCK-8 assay was performed to determine the half maximal inhibitory concentration (IC(50)) of MKN45/AR and MKN45 cells in the presence of different treatment. The mRNA expression of heat shock protein gene (HSPA1A and HSPA1B) was detected by RT-PCR, while the protein expression of heat shock protein 70 was analyzed using Western blot in MKN45/AR and MKN45 cells. Results: The IC(50) values of apatinib-sensitive and apatinib-resistant MKN45 cells were 10.411 μmol/L and 70.527 μmol/L, respectively, showing a significant difference ( P <0.05). The mRNA expression of HSPA1A and HSPA1B in MKN45/AR cells was significantly higher than that in MKN45 cells ( P <0.001). The protein expression of heat shock protein 70 was significantly decreased after 0.25 μmol/L triptolide treatment in MKN45/AR cells ( P <0.01). When heat shock protein 70 was inhibited by triptolide, the IC(50) value of apatinib in MKN45/AR cells was reduced to 11.679 μmol/L, which was significantly lower than cells treated with apatinib alone ( P <0.05). Conclusions: The apatinib-resistant MKN45 cells have high levels of heat shock protein 70. Low doses of triptolide can significantly inhibit heat shock protein 70, leading to reverse the resistance phenotype of MKN45/AR cells. Therefore, inhibition of heat shock protein 70 provides a new therapy strategy for patients with apatinib resistance.

Network analysis of oyster transcriptome revealed a cascade of cellular responses during recovery after heat shock.

PubMed

Zhang, Lingling; Hou, Rui; Su, Hailin; Hu, Xiaoli; Wang, Shi; Bao, Zhenmin

2012-01-01

Oysters, as a major group of marine bivalves, can tolerate a wide range of natural and anthropogenic stressors including heat stress. Recent studies have shown that oysters pretreated with heat shock can result in induced heat tolerance. A systematic study of cellular recovery from heat shock may provide insights into the mechanism of acquired thermal tolerance. In this study, we performed the first network analysis of oyster transcriptome by reanalyzing microarray data from a previous study. Network analysis revealed a cascade of cellular responses during oyster recovery after heat shock and identified responsive gene modules and key genes. Our study demonstrates the power of network analysis in a non-model organism with poor gene annotations, which can lead to new discoveries that go beyond the focus on individual genes.

Pattern of heat shock factor and heat shock protein expression in lymphocytes of bipolar patients: increased HSP70-glucocorticoid receptor heterocomplex.

PubMed

Bei, E S; Salpeas, V; Alevizos, B; Anagnostara, C; Pappa, D; Moutsatsou, P

2013-11-01

Bipolar disorder (BD), a stress-related disease, is characterized by altered glucocorticoid receptor (GR) signalling. Stress response includes activation of heat shock factor (HSF) and subsequent heat shock protein (HSP) synthesis which regulate GR folding and function. The objective of this study was to investigate the possible role of HSFs, HSPs and their interaction with GR in BD. We applied immunoprecipitation, SDS-PAGE/Western blot analysis and electrophoretic mobility shift assay (EMSA) in lymphocytes (whole cell or nuclear extracts) from BD patients and healthy subjects and determined the HSPs (HSP90 and HSP70), the heterocomplexes HSP90-GR and HSP70-GR, the HSFs (HSF1 and HSF4) as well as the HSF-DNA binding. The HSP70-GR heterocomplex was elevated (p < 0.05) in BD patients vs healthy subjects, and nuclear HSP70 was reduced (p ≤ 0.01) in bipolar manic patients. Protein levels of HSF1, HSF4, HSP90, HSP90-GR heterocomplex, and HSF-DNA binding remained unaltered in BD patients vs healthy subjects. The corresponding effect sizes (ES) indicated a large ES for HSP70-GR, HSP70, HSF-DNA binding and HSF4, and a medium ES for HSP90, HSF1 and HSP90-GR between healthy subjects and bipolar patients. Significant correlations among HSFs, HSPs, GR and HSP70-GR heterocomplex were observed in healthy subjects, which were abrogated in bipolar patients. The higher interaction between GR and HSP70 and the disturbances in the relations among heat shock response parameters and GR as observed in our BD patients may provide novel insights into the contribution of these factors in BD aetiopathogenesis. Copyright © 2013. Published by Elsevier Ltd.

Genomic Heat Shock Element Sequences Drive Cooperative Human Heat Shock Factor 1 DNA Binding and Selectivity*

PubMed Central

Jaeger, Alex M.; Makley, Leah N.; Gestwicki, Jason E.; Thiele, Dennis J.

2014-01-01

The heat shock transcription factor 1 (HSF1) activates expression of a variety of genes involved in cell survival, including protein chaperones, the protein degradation machinery, anti-apoptotic proteins, and transcription factors. Although HSF1 activation has been linked to amelioration of neurodegenerative disease, cancer cells exhibit a dependence on HSF1 for survival. Indeed, HSF1 drives a program of gene expression in cancer cells that is distinct from that activated in response to proteotoxic stress, and HSF1 DNA binding activity is elevated in cycling cells as compared with arrested cells. Active HSF1 homotrimerizes and binds to a DNA sequence consisting of inverted repeats of the pentameric sequence nGAAn, known as heat shock elements (HSEs). Recent comprehensive ChIP-seq experiments demonstrated that the architecture of HSEs is very diverse in the human genome, with deviations from the consensus sequence in the spacing, orientation, and extent of HSE repeats that could influence HSF1 DNA binding efficacy and the kinetics and magnitude of target gene expression. To understand the mechanisms that dictate binding specificity, HSF1 was purified as either a monomer or trimer and used to evaluate DNA-binding site preferences in vitro using fluorescence polarization and thermal denaturation profiling. These results were compared with quantitative chromatin immunoprecipitation assays in vivo. We demonstrate a role for specific orientations of extended HSE sequences in driving preferential HSF1 DNA binding to target loci in vivo. These studies provide a biochemical basis for understanding differential HSF1 target gene recognition and transcription in neurodegenerative disease and in cancer. PMID:25204655

Monitoring the change of mitochondrial morphology and its metabolism of the breast cancer cells with the treatment of Hsp70 inhibitor during heat shock by fluorescence imaging

NASA Astrophysics Data System (ADS)

Yu, Biying; Yang, Hongqin; Zhang, Xiaoman; Li, Hui

2016-10-01

Heat shock (HS) is one of the best-studied exogenous cellular stresses, and all cellular compartments and metabolic processes are involved in HS response. The heat shock proteins (Hsps) expression enhanced during HS mainly localized in subcellular compartments, such as cytosol, endoplasmic reticulum and mitochandria. The major inducible heat shock protein 70 (Hsp70) modulate cellular homeostasis and promote cellular survival by blocking a caspase independent cell death through its association with apoptosis inducing factor. Mitochondria as the critical elements of HS response that participate in key metabolic reactions, and the changes in mitochonrial morphology may impact on mitochondrial metabolism. In this paper, the changes of mitorchondrial morphology in breast cancer cell have been monitored in real time after heat shock (43 °) by the fluorescence imaging, and the influence of Hsp70 inhibitor on mitochandrial structures have also been investigated. Then the information of mitochondrial metabolism which can be characterized by the level of the mitochondrial membrane potential has also been obtained wihout/with the treatment of Hsp70 inhibitor. Our data indicated that the mitochandrial morphology were related with the mitochandrial membrane potential, and the mitochandrial membrane potential was influenced significantly with the treatment of Hsp70 inhibitor during HS.

DNA transformation via local heat shock

NASA Astrophysics Data System (ADS)

Li, Sha; Meadow Anderson, L.; Yang, Jui-Ming; Lin, Liwei; Yang, Haw

2007-07-01

This work describes transformation of foreign DNA into bacterial host cells by local heat shock using a microfluidic system with on-chip, built-in platinum heaters. Plasmid DNA encoding ampicillin resistance and a fluorescent protein can be effectively transformed into the DH5α chemically competent E. coli using this device. Results further demonstrate that only one-thousandth of volume is required to obtain transformation efficiencies as good as or better than conventional practices. As such, this work complements other lab-on-a-chip technologies for potential gene cloning/therapy and protein expression applications.

EFFECTS OF HEAT AND BROMOCHLOROACETIC ACID ON MALE REPRODUCTION IN HEAT SHOCK FACTOR-1 GENE KNOCKOUT MICE

EPA Science Inventory

Effects of heat and bromochloroacetic acid on male reproduction in heat shock factor-1 gene knockout mice.
Luft JC1, IJ Benjamin2, JB Garges1 and DJ Dix1. 1Reproductive Toxicology Division, USEPA, RTP, NC, 27711 and 2Dept of Internal Medicine, Univ.of Texas Southwestern Med C...

Asymmetric shock heating and the terrestrial magma ocean origin of the Moon.

PubMed

Karato, Shun-ichiro

2014-01-01

One of the difficulties of the current giant impact model for the origin of the Moon is to explain the marked similarity in the isotopic compositions and the substantial differences in the major element chemistry. Physics of shock heating is analyzed to show that the degree of heating is asymmetric between the impactor and the target, if the target (the proto-Earth) had a magma-ocean but the impactor did not. The magma ocean is heated much more than the solid impactor and the vapor-rich jets come mainly from the magma-ocean from which the Moon might have been formed. In this scenario, the similarity and differences in the composition between the Moon and Earth would be explained as a natural consequence of a collision in the later stage of planetary formation. Including the asymmetry in shock heating is the first step toward explaining the chemical composition of the Moon.

Genetic variation in heat shock protein 70 is associated with septic shock: narrowing the association to a specific haplotype.

PubMed

Kee, C; Cheong, K Y; Pham, K; Waterer, G W; Temple, S E L

2008-12-01

Heat shock protein 70 (HSP70) plays a major role in immune responses. Polymorphisms within the gene have been associated with development of septic shock. This study refines the region of the HSP70 gene associated with development of septic shock and confirms its functionality. Subjects (n = 31) were grouped into one of three haplotypes based on their HSPA1B-179C>T and HSPA1B1267A>G genotypes. Mononuclear cells from these subjects were stimulated with heat-killed bacteria (10(7 )colony-forming units/mL Escherichia coli or Streptococcus pneumoniae) for 8 and 21 h. HSP70 and tumour necrosis factor (TNF) mRNA and protein levels were measured by reverse transcriptase-polymerase chain reaction and ELISA, respectively. The HSPA1B-179*C:1267*A haplotype was associated with significantly lower levels of HSPA1B mRNA and protein and higher production of TNF mRNA and protein compared to the other haplotypes. Induction of HSP70 was TNF independent. These results suggest that the HSPA1B-179C>T:1267A>G haplotype is functional and may explain the association of the HSP70 gene with development of septic shock.

Recruitment of phosphorylated small heat shock protein Hsp27 to nuclear speckles without stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bryantsev, A.L.; Chechenova, M.B.; Shelden, E.A.

During stress, the mammalian small heat shock protein Hsp27 enters cell nuclei. The present study examines the requirements for entry of Hsp27 into nuclei of normal rat kidney (NRK) renal epithelial cells, and for its interactions with specific nuclear structures. We find that phosphorylation of Hsp27 is necessary for the efficient entry into nuclei during heat shock but not sufficient for efficient nuclear entry under control conditions. We further report that Hsp27 is recruited to an RNAse sensitive fraction of SC35 positive nuclear speckles, but not other intranuclear structures, in response to heat shock. Intriguingly, Hsp27 phosphorylation, in the absencemore » of stress, is sufficient for recruitment to speckles found in post-anaphase stage mitotic cells. Additionally, pseudophosphorylated Hsp27 fused to a nuclear localization peptide (NLS) is recruited to nuclear speckles in unstressed interphase cells, but wildtype and nonphosphorylatable Hsp27 NLS fusion proteins are not. The expression of NLS-Hsp27 mutants does not enhance colony forming abilities of cells subjected to severe heat shock, but does regulate nuclear speckle morphology. These data demonstrate that phosphorylation, but not stress, mediates Hsp27 recruitment to an RNAse soluble fraction of nuclear speckles and support a site-specific role for Hsp27 within the nucleus.« less

Hydrodynamic modelling of accretion impacts in classical T Tauri stars: radiative heating of the pre-shock plasma

NASA Astrophysics Data System (ADS)

Costa, G.; Orlando, S.; Peres, G.; Argiroffi, C.; Bonito, R.

2017-01-01

Context. It is generally accepted that, in classical T Tauri stars, the plasma from the circumstellar disc accretes onto the stellar surface with free-fall velocity and the impact generates a shock. The impact region is expected to contribute to emission in different spectral bands; many studies have confirmed that the X-rays arise from the post-shock plasma but, otherwise, there are no studies in the literature investigating the origin of the observed UV emission which is apparently correlated to accretion. Aims: We investigated the effect of radiative heating of the infalling material by the post-shock plasma at the base of the accretion stream, with the aim to identify in which region a significant part of the UV emission originates. Methods: We developed a one-dimensional hydrodynamic model describing the impact of an accretion stream onto the stellar surface; the model takes into account the gravity, the radiative cooling of an optically thin plasma, the thermal conduction, and the heating due to absorption of X-ray radiation. The latter term represents the heating of the infalling plasma due to the absorption of X-rays emitted from the post-shock region. Results: We found that the radiative heating of the pre-shock plasma plays a non-negligible role in the accretion phenomenon. In particular, the dense and cold plasma of the pre-shock accretion column is gradually heated up to a few 105K due to irradiation of X-rays arising from the shocked plasma at the impact region. This heating mechanism does not affect significantly the dynamics of the post-shock plasma. On the other hand, a region of radiatively heated gas (that we consider a precursor) forms in the unshocked accretion column and contributes significantly to UV emission. Our model naturally reproduces the luminosity of UV emission lines correlated to accretion and shows that most of the UV emission originates from the precursor.

Electron Heating in Low Mach Number Perpendicular Shocks. II. Dependence on the Pre-shock Conditions

NASA Astrophysics Data System (ADS)

Guo, Xinyi; Sironi, Lorenzo; Narayan, Ramesh

2018-05-01

Recent X-ray observations of merger shocks in galaxy clusters have shown that the post-shock plasma is two-temperature, with the protons being hotter than the electrons. In this work, the second of a series, we investigate the efficiency of irreversible electron heating in perpendicular low Mach number shocks, by means of two-dimensional particle-in-cell simulations. We consider values of plasma beta (the ratio of thermal and magnetic pressures) in the range 4 ≲ β p0 ≲ 32, and sonic Mach number (the ratio of shock speed to pre-shock sound speed) in the range 2 ≲ M s ≲ 5, as appropriate for galaxy cluster shocks. As shown in Paper I, magnetic field amplification—induced by shock compression of the pre-shock field, or by strong proton cyclotron and mirror modes accompanying the relaxation of proton temperature anisotropy—can drive the electron temperature anisotropy beyond the threshold of the electron whistler instability. The growth of whistler waves breaks the electron adiabatic invariance, and allows for efficient entropy production. We find that the post-shock electron temperature T e2 exceeds the adiabatic expectation {T}e2,{ad} by an amount ({T}e2-{T}e2,{ad})/{T}e0≃ 0.044 {M}s({M}s-1) (here, T e0 is the pre-shock temperature), which depends only weakly on the plasma beta over the range 4 ≲ β p0 ≲ 32 that we have explored, as well as on the proton-to-electron mass ratio (the coefficient of ≃0.044 is measured for our fiducial {m}i/{m}e=49, and we estimate that it will decrease to ≃0.03 for the realistic mass ratio). Our results have important implications for current and future observations of galaxy cluster shocks in the radio band (synchrotron emission and Sunyaev–Zel’dovich effect) and at X-ray frequencies.

Shock Heating of the Merging Galaxy Cluster A521

NASA Technical Reports Server (NTRS)

Bourdin, H.; Mazzotta, P.; Markevitch, M.; Giacintucci, S.; Brunetti, G.

2013-01-01

A521 is an interacting galaxy cluster located at z = 0.247, hosting a low-frequency radio halo connected to an eastern radio relic. Previous Chandra observations hinted at the presence of an X-ray brightness edge at the position of the relic, which may be a shock front. We analyze a deep observation of A521 recently performed with XMM-Newton in order to probe the cluster structure up to the outermost regions covered by the radio emission. The cluster atmosphere exhibits various brightness and temperature anisotropies. In particular, two cluster cores appear to be separated by two cold fronts. We find two shock fronts, one that was suggested by Chandra and that is propagating to the east, and another to the southwestern cluster outskirt. The two main interacting clusters appear to be separated by a shock-heated region, which exhibits a spatial correlation with the radio halo. The outer edge of the radio relic coincides spatially with a shock front, suggesting that this shock is responsible for the generation of cosmic-ray electrons in the relic. The propagation direction and Mach number of the shock front derived from the gas density jump, M = 2.4 +/- 0.2, are consistent with expectations from the radio spectral index, under the assumption of Fermi I acceleration mechanism.

Heat Shock Partially Dissociates the Overlapping Modules of the Yeast Protein-Protein Interaction Network: A Systems Level Model of Adaptation

PubMed Central

Mihalik, Ágoston; Csermely, Peter

2011-01-01

Network analysis became a powerful tool giving new insights to the understanding of cellular behavior. Heat shock, the archetype of stress responses, is a well-characterized and simple model of cellular dynamics. S. cerevisiae is an appropriate model organism, since both its protein-protein interaction network (interactome) and stress response at the gene expression level have been well characterized. However, the analysis of the reorganization of the yeast interactome during stress has not been investigated yet. We calculated the changes of the interaction-weights of the yeast interactome from the changes of mRNA expression levels upon heat shock. The major finding of our study is that heat shock induced a significant decrease in both the overlaps and connections of yeast interactome modules. In agreement with this the weighted diameter of the yeast interactome had a 4.9-fold increase in heat shock. Several key proteins of the heat shock response became centers of heat shock-induced local communities, as well as bridges providing a residual connection of modules after heat shock. The observed changes resemble to a ‘stratus-cumulus’ type transition of the interactome structure, since the unstressed yeast interactome had a globally connected organization, similar to that of stratus clouds, whereas the heat shocked interactome had a multifocal organization, similar to that of cumulus clouds. Our results showed that heat shock induces a partial disintegration of the global organization of the yeast interactome. This change may be rather general occurring in many types of stresses. Moreover, other complex systems, such as single proteins, social networks and ecosystems may also decrease their inter-modular links, thus develop more compact modules, and display a partial disintegration of their global structure in the initial phase of crisis. Thus, our work may provide a model of a general, system-level adaptation mechanism to environmental changes. PMID:22022244

Manipulation of gene expression by infrared laser heat shock and its application to the study of tracheal development in Drosophila.

PubMed

Miao, Guangxia; Hayashi, Shigeo

2015-03-01

Induction of gene expression in a specific cell and a defined time window is desirable to investigate gene function at the cellular level during morphogenesis. To achieve this, we attempted to introduce the infrared laser-evoked gene operator system (IR-LEGO, Kamei et al., 2009) in the Drosophila embryo. In this technique, infrared laser light illumination induces genes to be expressed under the control of heat shock promoters at the single cell level. We applied IR-LEGO to a transgenic fly stock, HS-eGFP, in which the enhanced green fluorescent protein (eGFP) gene is placed under the control of heat shock protein 70 promoter, and showed that eGFP expression can be induced in single cells within 1-2 hr after IR illumination. Furthermore, induction of HS-Branchless transgene encoding the Drosophila fibroblast growth factor (FGF) effectively altered the migration and branching patterns of the tracheal system. Our results indicated that IR-LEGO is a promising choice for the timely control of gene expression in a small group of cells in the Drosophila embryo. By using IR-LEGO, we further demonstrated that the tracheal terminal branching program is sensitive to localized expression of exogenous FGF. © 2014 Wiley Periodicals, Inc.

Shock-induced heating and millisecond boiling in gels and tissue due to high intensity focused ultrasound

PubMed Central

Canney, Michael S.; Khokhlova, Vera A.; Bessonova, Olga V.; Bailey, Michael R.; Crum, Lawrence A.

2009-01-01

Nonlinear propagation causes high intensity ultrasound waves to distort and generate higher harmonics, which are more readily absorbed and converted to heat than the fundamental frequency. Although such nonlinear effects have previously been investigated and found not to significantly alter high intensity focused ultrasound (HIFU) treatments, two results reported here change this paradigm. One is that at clinically relevant intensity levels, HIFU waves not only become distorted but form shock waves in tissue. The other is that the generated shock waves heat the tissue to boiling in much less time than predicted for undistorted or weakly distorted waves. In this study, a 2-MHz HIFU source operating at peak intensities up to 25,000 W/cm2 was used to heat transparent tissue-mimicking phantoms and ex vivo bovine liver samples. Initiation of boiling was detected using high-speed photography, a 20-MHz passive cavitation detector, and fluctuation of the drive voltage at the HIFU source. The time to boil obtained experimentally was used to quantify heating rates and was compared to calculations using weak shock theory and the shock amplitudes obtained from nonlinear modeling and from measurements with a fiber optic hydrophone. As observed experimentally and predicted by calculations, shocked focal waveforms produced boiling in as little as 3 ms and the time to initiate boiling was sensitive to small changes in HIFU output. Nonlinear heating due to shock waves is therefore important to HIFU and clinicians should be aware of the potential for very rapid boiling since it alters treatments. PMID:20018433

Al 1s-2p absorption spectroscopy of shock-wave heating and compression in laser-driven planar foil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sawada, H.; Regan, S. P.; Radha, P. B.

Time-resolved Al 1s-2p absorption spectroscopy is used to diagnose direct-drive, shock-wave heating and compression of planar targets having nearly Fermi-degenerate plasma conditions (T{sub e}{approx}10-40 eV, {rho}{approx}3-11 g/cm{sup 3}) on the OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. A planar plastic foil with a buried Al tracer layer was irradiated with peak intensities of 10{sup 14}-10{sup 15} W/cm{sup 2} and probed with the pseudocontinuum M-band emission from a point-source Sm backlighter in the range of 1.4-1.7 keV. The laser ablation process launches 10-70 Mbar shock waves into the CH/Al/CH target. The Al 1s-2p absorption spectramore » were analyzed using the atomic physic code PRISMSPECT to infer T{sub e} and {rho} in the Al layer, assuming uniform plasma conditions during shock-wave heating, and to determine when the heat front penetrated the Al layer. The drive foils were simulated with the one-dimensional hydrodynamics code LILAC using a flux-limited (f=0.06 and f=0.1) and nonlocal thermal-transport model [V. N. Goncharov et al., Phys. Plasmas 13, 012702 (2006)]. The predictions of simulated shock-wave heating and the timing of heat-front penetration are compared to the observations. The experimental results for a wide variety of laser-drive conditions and buried depths have shown that the LILAC predictions using f=0.06 and the nonlocal model accurately model the shock-wave heating and timing of the heat-front penetration while the shock is transiting the target. The observed discrepancy between the measured and simulated shock-wave heating at late times of the drive can be explained by the reduced radiative heating due to lateral heat flow in the corona.« less

Effects of heat stress on serum insulin, adipokines, AMP-activated protein kinase, and heat shock signal molecules in dairy cows.

PubMed

Min, Li; Cheng, Jian-bo; Shi, Bao-lu; Yang, Hong-jian; Zheng, Nan; Wang, Jia-qi

2015-06-01

Heat stress affects feed intake, milk production, and endocrine status in dairy cows. The temperature-humidity index (THI) is employed as an index to evaluate the degree of heat stress in dairy cows. However, it is difficult to ascertain whether THI is the most appropriate measurement of heat stress in dairy cows. This experiment was conducted to investigate the effects of heat stress on serum insulin, adipokines (leptin and adiponectin), AMP-activated protein kinase (AMPK), and heat shock signal molecules (heat shock transcription factor (HSF) and heat shock proteins (HSP)) in dairy cows and to research biomarkers to be used for better understanding the meaning of THI as a bioclimatic index. To achieve these objectives, two experiments were performed. The first experiment: eighteen lactating Holstein dairy cows were used. The treatments were: heat stress (HS, THI average=81.7, n=9) and cooling (CL, THI average=53.4, n=9). Samples of HS were obtained on August 16, 2013, and samples of CL were collected on April 7, 2014 in natural conditions. The second experiment: HS treatment cows (n=9) from the first experiment were fed for 8 weeks from August 16, 2013 to October 12, 2013. Samples for moderate heat stress, mild heat stress, and no heat stress were obtained, respectively, according to the physical alterations of the THI. Results showed that heat stress significantly increased the serum adiponectin, AMPK, HSF, HSP27, HSP70, and HSP90 (P<0.05). Adiponectin is strongly associated with AMPK. The increases of adiponectin and AMPK may be one of the mechanisms to maintain homeostasis in heat-stressed dairy cows. When heat stress treatment lasted 8 weeks, a higher expression of HSF and HSP70 was observed under moderate heat stress. Serum HSF and HSP70 are sensitive and accurate in heat stress and they could be potential indicators of animal response to heat stress. We recommend serum HSF and HSP70 as meaningful biomarkers to supplement the THI and evaluate moderate heat

Effects of heat stress on serum insulin, adipokines, AMP-activated protein kinase, and heat shock signal molecules in dairy cows*

PubMed Central

Min, Li; Cheng, Jian-bo; Shi, Bao-lu; Yang, Hong-jian; Zheng, Nan; Wang, Jia-qi

2015-01-01

Heat stress affects feed intake, milk production, and endocrine status in dairy cows. The temperature-humidity index (THI) is employed as an index to evaluate the degree of heat stress in dairy cows. However, it is difficult to ascertain whether THI is the most appropriate measurement of heat stress in dairy cows. This experiment was conducted to investigate the effects of heat stress on serum insulin, adipokines (leptin and adiponectin), AMP-activated protein kinase (AMPK), and heat shock signal molecules (heat shock transcription factor (HSF) and heat shock proteins (HSP)) in dairy cows and to research biomarkers to be used for better understanding the meaning of THI as a bioclimatic index. To achieve these objectives, two experiments were performed. The first experiment: eighteen lactating Holstein dairy cows were used. The treatments were: heat stress (HS, THI average=81.7, n=9) and cooling (CL, THI average=53.4, n=9). Samples of HS were obtained on August 16, 2013, and samples of CL were collected on April 7, 2014 in natural conditions. The second experiment: HS treatment cows (n=9) from the first experiment were fed for 8 weeks from August 16, 2013 to October 12, 2013. Samples for moderate heat stress, mild heat stress, and no heat stress were obtained, respectively, according to the physical alterations of the THI. Results showed that heat stress significantly increased the serum adiponectin, AMPK, HSF, HSP27, HSP70, and HSP90 (P<0.05). Adiponectin is strongly associated with AMPK. The increases of adiponectin and AMPK may be one of the mechanisms to maintain homeostasis in heat-stressed dairy cows. When heat stress treatment lasted 8 weeks, a higher expression of HSF and HSP70 was observed under moderate heat stress. Serum HSF and HSP70 are sensitive and accurate in heat stress and they could be potential indicators of animal response to heat stress. We recommend serum HSF and HSP70 as meaningful biomarkers to supplement the THI and evaluate moderate heat

Differential expression of hsp70 stress proteins in human endothelial cells exposed to heat shock and hydrogen peroxide.

PubMed

Jornot, L; Mirault, M E; Junod, A F

1991-09-01

The potential role of oxidative stress conditions in the induction of heat shock proteins was studied in human umbilical vein endothelial cells. We compared the effects of temperature (43 to 45 degrees C), exposure to hydrogen peroxide (H2O2) and oxygen metabolites generated by the enzyme system hypoxanthine-xanthine oxidase (O2- plus H2O2), as well as exposure to 95% O2, on the expression of the major 70-kD heat shock proteins (hsp70). Northern blot analysis indicated that: (1) heat shock induced a rapid and marked increase in hsp70 mRNA levels that reached a maximum during recovery from a 30-min exposure to 45 degrees C; (2) treatment with a 5-mM H2O2 bolus or 50 mU/ml xanthine oxidase also increased hsp70 mRNA levels but to a lesser extent than heat shock (about 10 and 25 times less, respectively); (3) no change was detected after a 5-day exposure to 95% O2. Nuclear run on transcription data and kinetics of mRNA decay in the presence of actinomycin D indicated that the observed increase in hsp70 mRNA levels in both heat-shocked and H2O2-treated cells was mainly due to a transcriptional induction. The kinetics of hsp70 synthesis correlated with the accumulation of hsp70 mRNA. Two-dimensional gel electrophoresis and immunologic analysis of these heat shock proteins revealed a series of at least five distinct hsp70 isoforms induced in heat-shocked cells, whereas only a specific subset of these proteins, mainly one acidic isoform, was induced in very low amounts in response to H2O2 treatment. These results clearly indicate that the endothelial cell responses to oxidative stress and heat shock differ in both qualitative and quantitative terms in respect to hsp70 induction. They also suggest that the intensity of this response to oxidative stress conditions may vary depending on the nature of the oxidative challenge.

Asymmetric shock heating and the terrestrial magma ocean origin of the Moon

PubMed Central

KARATO, Shun-ichiro

2014-01-01

One of the difficulties of the current giant impact model for the origin of the Moon is to explain the marked similarity in the isotopic compositions and the substantial differences in the major element chemistry. Physics of shock heating is analyzed to show that the degree of heating is asymmetric between the impactor and the target, if the target (the proto-Earth) had a magma-ocean but the impactor did not. The magma ocean is heated much more than the solid impactor and the vapor-rich jets come mainly from the magma-ocean from which the Moon might have been formed. In this scenario, the similarity and differences in the composition between the Moon and Earth would be explained as a natural consequence of a collision in the later stage of planetary formation. Including the asymmetry in shock heating is the first step toward explaining the chemical composition of the Moon. PMID:24621956

Expressed sequence tags from heat-shocked seagrass Zostera noltii (Hornemann) from its southern distribution range.

PubMed

Massa, Sónia I; Pearson, Gareth A; Aires, Tânia; Kube, Michael; Olsen, Jeanine L; Reinhardt, Richard; Serrão, Ester A; Arnaud-Haond, Sophie

2011-09-01

Predicted global climate change threatens the distributional ranges of species worldwide. We identified genes expressed in the intertidal seagrass Zostera noltii during recovery from a simulated low tide heat-shock exposure. Five Expressed Sequence Tag (EST) libraries were compared, corresponding to four recovery times following sub-lethal temperature stress, and a non-stressed control. We sequenced and analyzed 7009 sequence reads from 30min, 2h, 4h and 24h after the beginning of the heat-shock (AHS), and 1585 from the control library, for a total of 8594 sequence reads. Among 51 Tentative UniGenes (TUGs) exhibiting significantly different expression between libraries, 19 (37.3%) were identified as 'molecular chaperones' and were over-expressed following heat-shock, while 12 (23.5%) were 'photosynthesis TUGs' generally under-expressed in heat-shocked plants. A time course analysis of expression showed a rapid increase in expression of the molecular chaperone class, most of which were heat-shock proteins; which increased from 2 sequence reads in the control library to almost 230 in the 30min AHS library, followed by a slow decrease during further recovery. In contrast, 'photosynthesis TUGs' were under-expressed 30min AHS compared with the control library, and declined progressively with recovery time in the stress libraries, with a total of 29 sequence reads 24h AHS, compared with 125 in the control. A total of 4734 TUGs were screened for EST-Single Sequence Repeats (EST-SSRs) and 86 microsatellites were identified. Copyright © 2011 Elsevier B.V. All rights reserved.

Expression of Small Heat-Shock Proteins at Low Temperatures1

PubMed Central

Sabehat, Adnan; Lurie, Susan; Weiss, David

1998-01-01

We previously reported that short exposure of tomato (Lycopersicon esculentum L.) fruits to high temperature protects them from chilling injury. To study the involvement of heat-shock proteins (HSPs) in the acquisition of low-temperature tolerance, we cloned two heat-shock-induced genes that are also expressed at low temperatures. The cloned cDNAs belong to the small HSP group. Sequence analyses of the clones showed perfect homology to the tomato-ripening gene tom66 and to the tomato chloroplastic HSP21 gene tom111. The expression of both genes was induced by high temperature in fruits, flowers, leaves, and stems, but not by low or ambient temperatures or by other stresses such as drought and anaerobic conditions. When the heated fruits were transferred to low temperature, tom66 and tom111 mRNA levels first decreased but were then reinduced. Induction was not observed in nonheated fruits at low temperature. Immunodetection of tom111-encoded protein indicated that this protein is present at low temperatures in the heated fruits. The results of this study show that the expression of tom66 and tom111 is correlated with protection against some, but not all, symptoms of chilling injury. PMID:9625718

Seasonal effects of heat shock on bacterial populations, including artificial Vibrio parahaemolyticus exposure, in the Pacific oyster, Crassostrea gigas.

PubMed

Aagesen, Alisha M; Häse, Claudia C

2014-04-01

During the warmer summer months, oysters are conditioned to spawn, resulting in massive physiological efforts for gamete production. Moreover, the higher temperatures during the summer typically result in increased bacteria populations in oysters. We hypothesized that these animals are under multiple stresses that lead to possible immune system impairments during the summer months that can possibly lead to death. Here we show that in the summer and the fall animals exposed to a short heat stress respond similarly, resulting in a general trend of more bacteria being found in heat shocked animals than their non-heat shocked counterparts. We also show that naturally occurring bacterial populations are effected by a heat shock. In addition, oysters artificially contaminated with Vibrio parahaemolyticus were also affected by a heat shock. Heat shocked animals contained higher concentrations of V. parahaemolyticus in their tissues and hemolymph than control animals and this was consistent for animals examined during summer and fall. Finally, oyster hemocyte interactions with V. parahaemolyticus differed based on the time of the year. Overall, these findings demonstrate that seasonal changes and/or a short heat shock is sufficient to impact bacterial retention, particularly V. parahaemolyticus, in oysters and this line of research might lead to important considerations for animal harvesting procedures. Copyright © 2013 Elsevier Ltd. All rights reserved.

Heating the polar corona by collisionless shocks: an example of cross-fertilization in space physics

NASA Astrophysics Data System (ADS)

Zimbardo, Gaetano; Nistico, Giuseppe

We propose a new model for explaining the observations of preferential heating of heavy ions in the polar solar corona. We consider that a large number of small scale shock waves can be present in the solar corona, as suggested by recent observations of polar coronal jets. The heavy ion energization mechanism is, essentially, the ion reflection off supercritical quasi-perpendicular collisionless shocks in the corona and the subsequent acceleration by the motional electric field E = -V × B. The mechanism of heavy ion reflection is based on ion gyration in the magnetic overshoot of the shock. The acceleration due to E is perpendicular to the magnetic field, giving rise to large temperature anisotropy with T⊥ T , in agreement with observations. Also, heating is more than mass proportional with respect to protons, because the heavy ion orbit is mostly upstream of the quasi-perpendicular shock foot. The observed temperature ratios between O5+ ions and protons in the polar corona, and between α particles and protons in the solar wind are easily recovered. Results of numerical simulations reproducing the heavy ion reflection will be presented. This work is an interesting example of cross-fertilization in space plasma physics: the non adiabatic heating of heavy ions comes from Speiser orbits in the magnetotail, observations of preferential heating of heavy ions at shocks comes from Ulysses data on corotating interaction regions shocks, heavy ion reflecton from a magnetic barrier is akin to the ion orbits in the Ferraro-Rosenbluth sheath considered for the magnetopause, the formation of shocks in the reconnection outflow regions comes from solar flare models, and evidence of reconnection and fast flows in the polar corona comes from Hinode and STEREO observations of coronal hole jets.

A potential role for Helicobacter pylori heat shock protein 60 in gastric tumorigenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Chen-Si; School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan; He, Pei-Juin

2010-02-05

Helicobacter pylori has been found to promote the malignant process leading to gastric cancer. Heat shock protein 60 of H. pylori (HpHSP60) was previously been identified as a potent immunogene. This study investigates the role of HpHSP60 in gastric cancer carcinogenesis. The effect of HpHSP60 on cell proliferation, anti-death activity, angiogenesis and cell migration were explored. The results showed that HpHSP60 enhanced migration by gastric cancer cells and promoted tube formation by umbilical vein endothelial cells (HUVECs); however, HpHSP60 did not increase cell proliferation nor was this protein able to rescue gastric cancer cells from death. Moreover, the results alsomore » indicated HpHSP60 had different effects on AGS gastric cancer cells or THP-1 monocytic cells in terms of their expression of pro-inflammatory cytokines, which are known to be important to cancer development. We propose that HpHSP60 may trigger the initiation of carcinogenesis by inducing pro-inflammatory cytokine release and by promoting angiogenesis and metastasis. Thus, this extracellular pathogen-derived HSP60 is potentially a vigorous virulence factor that can act as a carcinogen during gastric tumorigenesis.« less

New Evidence for Efficient Collisionless Heating of Electrons at the Reverse Shock of a Young Supernova Remnant

NASA Technical Reports Server (NTRS)

Yamaguchi, Hiroya; Eriksen, Kristoffer A.; Badenes, Carles; Hughes, John P.; Brickhouse, Nancy S.; Foster, Adam R.; Patnaude, Daniel J.; Petre, Robert; Slane, Patrick O.; Smith, Randall K.

2013-01-01

Although collisionless shocks are ubiquitous in astrophysics, certain key aspects of them are not well understood. In particular, the process known as collisionless electron heating, whereby electrons are rapidly energized at the shock front, is one of the main open issues in shock physics. Here, we present the first clear evidence for efficient collisionless electron heating at the reverse shock of Tycho's supernova remnant (SNR), revealed by Fe K diagnostics using high-quality X-ray data obtained by the Suzaku satellite. We detect K beta (3p yields 1s) fluorescence emission from low-ionization Fe ejecta excited by energetic thermal electrons at the reverse shock front, which peaks at a smaller radius than Fe K alpha (2p yields 1s) emission dominated by a relatively highly ionized component. Comparisons with our hydrodynamical simulations imply instantaneous electron heating to a temperature 1000 times higher than expected from Coulomb collisions alone. The unique environment of the reverse shock, which is propagating with a high Mach number into rarefied ejecta with a low magnetic field strength, puts strong constraints on the physical mechanism responsible for this heating and favors a cross-shock potential created by charge deflection at the shock front. Our sensitive observation also reveals that the reverse shock radius of this SNR is about 10% smaller than the previous measurement using the Fe K alpha morphology from the Chandra observations. Since strong Fe K beta fluorescence is expected only from low-ionization plasma where Fe ions still have many 3p electrons, this feature is key to diagnosing the plasma state and distribution of the immediate postshock ejecta in a young SNR.

Translational control of small heat shock genes in mesophilic and thermophilic cyanobacteria by RNA thermometers

PubMed Central

Cimdins, Annika; Klinkert, Birgit; Aschke-Sonnenborn, Ursula; Kaiser, Friederike M; Kortmann, Jens; Narberhaus, Franz

2014-01-01

Cyanobacteria constitute a heterogeneous phylum of oxygen-producing, photosynthetic prokaryotes. They are susceptible to various stress conditions like heat, salt, or light stress, all inducing the cyanobacterial heat shock response (HSR). Cyanobacterial small heat shock proteins (sHsps) are known to preserve thylakoid membrane integrity under stress conditions, thereby protecting the photosynthesis machinery. In Synechocystis sp PCC 6803, synthesis of the sHsp Hsp17 is regulated by an RNA thermometer (RNAT) in the 5′-untranslated region (5′-UTR) of the hsp17 mRNA. RNATs are direct temperature sensors that control expression of many bacterial heat shock and virulence genes. They hinder translation at low temperatures by base pairing, thus blocking ribosome access to the mRNA.   To explore the temperature range in which RNATs act, we studied various RNAT candidates upstream of sHsp genes from mesophilic and thermophilic cyanobacteria. The mesophilic cyanobacteria Anabaena variabilis and Nostoc sp chromosomally encode two sHsps each. Reporter gene studies suggested RNAT-mediated post-transcriptional regulation of shsp expression in both organisms. Detailed structural analysis of the two A. variabilis candidates revealed two novel RNAT types. The first, avashort, regulates translation primarily by masking of the AUG translational start codon. The second, featuring an extended initial hairpin, thus named avalong, presumably makes use of complex tertiary interaction. The 5′-UTR of the small heat shock gene hspA in the thermophile Thermosynechococcus elongatus is predicted to adopt an extended secondary structure. Structure probing revealed that the ribosome binding site was blocked at temperatures below 55 °C. The results of this study demonstrate that cyanobacteria commonly use RNATs to control expression of their small heat shock genes. PMID:24755616

Radiative cooling in shock-heated hydrogen-helium plasmas. [for planetary entry probe heat shields

NASA Technical Reports Server (NTRS)

Poon, P. T. Y.; Stickford, G. H., Jr.

1978-01-01

Axial and off-axis radiative cooling of cylindrical shock-heated hydrogen-helium plasmas is investigated theoretically and experimentally. The coupled fluid dynamic-radiative transfer equations are solved by a combination of approximation techniques aimed at simplifying the computation of the flux divergence term, namely, the quasi-isothermal approximation and the exponential approximation developed for the solid angle integration. The accuracy of the approximation schemes has been assessed and found acceptable for applying the methods to the rapid computation of the radiatively coupled flow problem. Radiative cooling experiments were conducted in a 6-inch annular arc accelerator shock tube (ANAA) for an initial pressure of 1 torr and shock speeds from 35 to 45 Km/sec. The results indicate that the lateral cooling is small compared with the axial cooling, and that better agreement is achieved between the data and the theoretical results by inclusion of the lateral temperature gradient.

Heat shock protein 72: release and biological significance during exercise.

PubMed

Whitham, Martin; Fortes, Matthew Benjamin

2008-01-01

The cumulative stressors of exercise manifest themselves at a cellular level by threatening the protein homeostasis of the cell. In these conditions, Heat Shock Proteins (HSP) are synthesised to chaperone mis-folded and denatured proteins. As such, the intracellular HSP response is thought to aid cell survival in the face of otherwise lethal cellular stress. Recently, the inducible isoform of the 70 Kda heat shock protein family, Hsp72 has been detected in the extracellular environment. Furthermore, the release of this protein into the circulation has been shown to occur in response to a range of exercise bouts. The present review summarises the current research on the exercise Hsp72 response, the possible mediators and mechanisms of extracellular (e)Hsp72 release, and the possible biological significance of this systemic response. In particular, the possible role of eHsp72 in the modulation of immunity during exercise is discussed.

Arabidopsis HEAT SHOCK TRANSCRIPTION FACTORA1b regulates multiple developmental genes under benign and stress conditions.

PubMed

Albihlal, Waleed S; Obomighie, Irabonosi; Blein, Thomas; Persad, Ramona; Chernukhin, Igor; Crespi, Martin; Bechtold, Ulrike; Mullineaux, Philip M

2018-05-19

In Arabidopsis thaliana, HEAT SHOCK TRANSCRIPTION FACTORA1b (HSFA1b) controls resistance to environmental stress and is a determinant of reproductive fitness by influencing seed yield. To understand how HSFA1b achieves this, we surveyed its genome-wide targets (ChIP-seq) and its impact on the transcriptome (RNA-seq) under non-stress (NS), heat stress (HS) in the wild type, and in HSFA1b-overexpressing plants under NS. A total of 952 differentially expressed HSFA1b-targeted genes were identified, of which at least 85 are development associated and were bound predominantly under NS. A further 1780 genes were differentially expressed but not bound by HSFA1b, of which 281 were classified as having development-associated functions. These genes are indirectly regulated through a hierarchical network of 27 transcription factors (TFs). Furthermore, we identified 480 natural antisense non-coding RNA (cisNAT) genes bound by HSFA1b, defining a further mode of indirect regulation. Finally, HSFA1b-targeted genomic features not only harboured heat shock elements, but also MADS box, LEAFY, and G-Box promoter motifs. This revealed that HSFA1b is one of eight TFs that target a common group of stress defence and developmental genes. We propose that HSFA1b transduces environmental cues to many stress tolerance and developmental genes to allow plants to adjust their growth and development continually in a varying environment.

How specialized volatiles respond to chronic and short-term physiological and shock heat stress in Brassica nigra.

PubMed

Kask, Kaia; Kännaste, Astrid; Talts, Eero; Copolovici, Lucian; Niinemets, Ülo

2016-09-01

Brassicales release volatile glucosinolate breakdown products upon tissue mechanical damage, but it is unclear how the release of glucosinolate volatiles responds to abiotic stresses such as heat stress. We used three different heat treatments, simulating different dynamic temperature conditions in the field to gain insight into stress-dependent changes in volatile blends and photosynthetic characteristics in the annual herb Brassica nigra (L.) Koch. Heat stress was applied by either heating leaves through temperature response curve measurements from 20 to 40 °C (mild stress), exposing plants for 4 h to temperatures 25-44 °C (long-term stress) or shock-heating leaves to 45-50 °C. Photosynthetic reduction through temperature response curves was associated with decreased stomatal conductance, while the reduction due to long-term stress and collapse of photosynthetic activity after heat shock stress were associated with non-stomatal processes. Mild stress decreased constitutive monoterpene emissions, while long-term stress and shock stress resulted in emissions of the lipoxygenase pathway and glucosinolate volatiles. Glucosinolate volatile release was more strongly elicited by long-term stress and lipoxygenase product released by heat shock. These results demonstrate that glucosinolate volatiles constitute a major part of emission blend in heat-stressed B. nigra plants, especially upon chronic stress that leads to induction responses. © 2016 John Wiley & Sons Ltd.

Transcriptome Profiling of Selectively Bred Pacific Oyster Crassostrea gigas Families that Differ in Tolerance of Heat Shock

PubMed Central

Bayne, Christopher J.; Camara, Mark D.; Cunningham, Charles; Jenny, Matthew J.; Langdon, Christopher J.

2010-01-01

Sessile inhabitants of marine intertidal environments commonly face heat stress, an important component of summer mortality syndrome in the Pacific oyster Crassostrea gigas. Marker-aided selection programs would be useful for developing oyster strains that resist summer mortality; however, there is currently a need to identify candidate genes associated with stress tolerance and to develop molecular markers associated with those genes. To identify candidate genes for further study, we used cDNA microarrays to test the hypothesis that oyster families that had high (>64%) or low (<29%) survival of heat shock (43°C, 1 h) differ in their transcriptional responses to stress. Based upon data generated by the microarray and by real-time quantitative PCR, we found that transcription after heat shock increased for genes putatively encoding heat shock proteins and genes for proteins that synthesize lipids, protect against bacterial infection, and regulate spawning, whereas transcription decreased for genes for proteins that mobilize lipids and detoxify reactive oxygen species. RNAs putatively identified as heat shock protein 27, collagen, peroxinectin, S-crystallin, and two genes with no match in Genbank had higher transcript concentrations in low-surviving families than in high-surviving families, whereas concentration of putative cystatin B mRNA was greater in high-surviving families. These ESTs should be studied further for use in marker-aided selection programs. Low survival of heat shock could result from a complex interaction of cell damage, opportunistic infection, and metabolic exhaustion. PMID:19205802

HEAT SHOCK FACTOR 1-MEDIATED THERMOTOLERANCE PREVENTS CELL DEATH AND RESULTS IN G2/M CELL CYCLE ARREST

EPA Science Inventory

Mammalian cells respond to stress by activating heat shock transcription factors (e.g., HSF1) that regulate increased synthesis of heat shock proteins (HSPs). HSPs mediate protection from deleterious effects of stress by preventing permanent disruption of normal cellular mitosis...

α-Crystallins Are Small Heat Shock Proteins: Functional and Structural Properties.

PubMed

Tikhomirova, T S; Selivanova, O M; Galzitskaya, O V

2017-02-01

During its life cycle, a cell can be subjected to various external negative effects. Many proteins provide cell protection, including small heat shock proteins (sHsp) that have chaperone-like activity. These proteins have several important functions involving prevention of apoptosis and retention of cytoskeletal integrity; also, sHsp take part in the recovery of enzyme activity. The action mechanism of sHsp is based on the binding of hydrophobic regions exposed to the surface of a molten globule. α-Crystallins presented in chordate cells as two αA- and αB-isoforms are the most studied small heat shock proteins. In this review, we describe the main functions of α-crystallins, features of their secondary and tertiary structures, and examples of their partners in protein-protein interactions.

Sulforaphane activates heat shock response and enhances proteasome activity through up-regulation of Hsp27.

PubMed

Gan, Nanqin; Wu, Yu-Chieh; Brunet, Mathilde; Garrido, Carmen; Chung, Fung-Lung; Dai, Chengkai; Mi, Lixin

2010-11-12

It is conceivable that stimulating proteasome activity for rapid removal of misfolded and oxidized proteins is a promising strategy to prevent and alleviate aging-related diseases. Sulforaphane (SFN), an effective cancer preventive agent derived from cruciferous vegetables, has been shown to enhance proteasome activities in mammalian cells and to reduce the level of oxidized proteins and amyloid β-induced cytotoxicity. Here, we report that SFN activates heat shock transcription factor 1-mediated heat shock response. Specifically, SFN-induced expression of heat shock protein 27 (Hsp27) underlies SFN-stimulated proteasome activity. SFN-induced proteasome activity was significantly enhanced in Hsp27-overexpressing cells but absent in Hsp27-silenced cells. The role of Hsp27 in regulating proteasome activity was further confirmed in isogenic REG cells, in which SFN-induced proteasome activation was only observed in cells stably overexpressing Hsp27, but not in the Hsp27-free parental cells. Finally, we demonstrated that phosphorylation of Hsp27 is irrelevant to SFN-induced proteasome activation. This study provides a novel mechanism underlying SFN-induced proteasome activity. This is the first report to show that heat shock response by SFN, in addition to the antioxidant response mediated by the Keap1-Nrf2 pathway, may contribute to cytoprotection.

Geldanamycin induces heat shock protein 70 and protects against MPTP-induced dopaminergic neurotoxicity in mice.

PubMed

Shen, Hai-Ying; He, Jin-Cai; Wang, Yumei; Huang, Qing-Yuan; Chen, Jiang-Fan

2005-12-02

As key molecular chaperone proteins, heat shock proteins (HSPs) represent an important cellular protective mechanism against neuronal cell death in various models of neurological disorders. In this study, we investigated the effect as well as the molecular mechanism of geldanamycin (GA), an inhibitor of Hsp90, on 1-methyl-4-pheny-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic neurotoxicity, a mouse model of Parkinson disease. Neurochemical analysis showed that pretreatment with GA (via intracerebral ventricular injection 24 h prior to MPTP treatment) increased residual dopamine content and tyrosine hydroxylase immunoreactivity in the striatum 24 h after MPTP treatment. To dissect out the molecular mechanism underlying this neuroprotection, we showed that the GA-mediated protection against MPTP was associated with a reduction of cytosolic Hsp90 and an increase in Hsp70, with no significant changes in Hsp40 and Hsp25 levels. Furthermore, in parallel with the induction of Hsp70, striatal nuclear HSF1 levels and HSF1 binding to heat shock element sites in the Hsp70 promoter were significantly enhanced by the GA pretreatment. Together these results suggested that the molecular cascade leading to the induction of Hsp70 is critical to the neuroprotection afforded by GA against MPTP-induced neurotoxicity in the brain and that pharmacological inhibition of Hsp90 may represent a potential therapeutic strategy for Parkinson disease.

Inducing Heat Shock Proteins Enhances the Stemness of Frozen-Thawed Adipose Tissue-Derived Stem Cells.

PubMed

Shaik, Shahensha; Hayes, Daniel; Gimble, Jeffrey; Devireddy, Ram

2017-04-15

Extensive research has been performed to determine the effect of freezing protocol and cryopreservation agents on the viability of adipose tissue-derived stromal/stem cells (ASCs) as well as other cells. Unfortunately, the conclusion one may draw after decades of research utilizing fundamentally similar cryopreservation techniques is that a barrier exists, which precludes full recovery. We hypothesize that agents capable of inducing a subset of heat shock proteins (HSPs) and chaperones will reduce the intrinsic barriers to the post-thaw recovery of ASCs. ASCs were exposed to 43°C for 1 h to upregulate HSPs, and the temporal HSP expression profile postheat shock was determined by performing quantitative polymerase chain reaction (PCR) and western blotting assays. The expression levels of HSP70 and HSP32 were found to be maximum at 3 h after the heat shock, whereas HSP90 and HSP27 remain unchanged. The heat shocked ASCs cryopreserved during maximal HSPs expression exhibited increased post-thaw viability than the nonheat shocked samples. Histochemical staining and quantitative reverse transcription-PCR indicated that the ASC differentiation potential was retained. Thus, suggesting that the upregulation of HSPs before a freezing insult is beneficial to ASCs and a potential alternative to the use of harmful cryoprotective agents.

Translation Regulation and RNA Granule Formation after Heat Shock of Procyclic Form Trypanosoma brucei: Many Heat-Induced mRNAs Are also Increased during Differentiation to Mammalian-Infective Forms.

PubMed

Minia, Igor; Merce, Clementine; Terrao, Monica; Clayton, Christine

2016-09-01

African trypanosome procyclic forms multiply in the midgut of tsetse flies, and are routinely cultured at 27°C. Heat shocks of 37°C and above result in general inhibition of translation, and severe heat shock (41°C) results in sequestration of mRNA in granules. The mRNAs that are bound by the zinc-finger protein ZC3H11, including those encoding refolding chaperones, escape heat-induced translation inhibition. At 27°C, ZC3H11 mRNA is predominantly present as an untranslated cytosolic messenger ribonucleoprotein particle, but after heat shocks of 37°C-41°C, the ZC3H11 mRNA moves into the polysomal fraction. To investigate the scope and specificities of heat-shock translational regulation and granule formation, we analysed the distributions of mRNAs on polysomes at 27°C and after 1 hour at 39°C, and the mRNA content of 41°C heat shock granules. We found that mRNAs that bind to ZC3H11 remained in polysomes at 39°C and were protected from sequestration in granules at 41°C. As previously seen for starvation stress granules, the mRNAs that encode ribosomal proteins were excluded from heat-shock granules. 70 mRNAs moved towards the polysomal fraction after the 39°C heat shock, and 260 increased in relative abundance. Surprisingly, many of these mRNAs are also increased when trypanosomes migrate to the tsetse salivary glands. It therefore seems possible that in the wild, temperature changes due to diurnal variations and periodic intake of warm blood might influence the efficiency with which procyclic forms develop into mammalian-infective forms.

Heat shock factor-1 intertwines insulin/IGF-1, TGF-β and cGMP signaling to control development and aging.

PubMed

Barna, János; Princz, Andrea; Kosztelnik, Mónika; Hargitai, Balázs; Takács-Vellai, Krisztina; Vellai, Tibor

2012-11-01

Temperature affects virtually all cellular processes. A quick increase in temperature challenges the cells to undergo a heat shock response to maintain cellular homeostasis. Heat shock factor-1 (HSF-1) functions as a major player in this response as it activates the transcription of genes coding for molecular chaperones (also called heat shock proteins) that maintain structural integrity of proteins. However, the mechanisms by which HSF-1 adjusts fundamental cellular processes such as growth, proliferation, differentiation and aging to the ambient temperature remain largely unknown. We demonstrate here that in Caenorhabditis elegans HSF-1 represses the expression of daf-7 encoding a TGF-β (transforming growth factor-beta) ligand, to induce young larvae to enter the dauer stage, a developmentally arrested, non-feeding, highly stress-resistant, long-lived larval form triggered by crowding and starvation. Under favorable conditions, HSF-1 is inhibited by crowding pheromone-sensitive guanylate cyclase/cGMP (cyclic guanosine monophosphate) and systemic nutrient-sensing insulin/IGF-1 (insulin-like growth factor-1) signaling; loss of HSF-1 activity allows DAF-7 to promote reproductive growth. Thus, HSF-1 interconnects the insulin/IGF-1, TGF-β and cGMP neuroendocrine systems to control development and longevity in response to diverse environmental stimuli. Furthermore, HSF-1 upregulates another TGF-β pathway-interacting gene, daf-9/cytochrome P450, thereby fine-tuning the decision between normal growth and dauer formation. Together, these results provide mechanistic insight into how temperature, nutrient availability and population density coordinately influence development, lifespan, behavior and stress response through HSF-1.

Effects of heat shock protein 90 expression on pectoralis major oxidation in broilers exposed to acute heat stress.

PubMed

Hao, Y; Gu, X H

2014-11-01

This study was conducted to determine the effects of heat shock protein 90 (HSP90) expression on pH, lipid peroxidation, heat shock protein 70 (HSP70), and glucocorticoid receptor (GR) expression of pectoralis major in broilers exposed to acute heat stress. In total, 90 male broilers were randomly allocated to 3 groups: control (CON), heat stress (HS), or geldanamycin treatment (GA). On d 41, the broilers in the GA group were injected intraperitoneally with GA (5 μg/kg of BW), and the broilers in the CON and HS groups were injected intraperitoneally with saline. Twenty-four hours later, the broilers in the CON group were moved to environmental chambers controlled at 22°C for 2 h, and the broilers in the HS and GA groups were moved to environmental chambers controlled at 40°C for 2 h. The pH values of the pectoralis major after 30 min and 24 h of chilling after slaughter of HS and GA broilers were significantly lower (P < 0.01) than those of the CON broilers. Heat stress caused significant increases in sera corticosterone and lactic dehydrogenase, the activity of malondialdehyde and superoxide dismutase, the expression of HSP90 and HSP70, and nuclear expression of GR protein in the pectoralis major (P < 0.05). Heat stress induced a significant decrease in GR protein expression in the cytoplasm and GR mRNA expression. Furthermore, the low expression of HSP90 significantly increased levels of lactic dehydrogenase and malondialdehyde and GR protein expression in the cytoplasm under heat stress (P < 0.01), and significantly decreased nuclear GR protein expression (P < 0.01). Heat shock protein 90 was positively correlated with corticosterone and superoxide dismutase activities (P < 0.01), and HSP90 mRNA was negatively correlated with pH after chilling for 24 h. The results demonstrated that HSP90 plays a pivotal role in protecting cells from oxidation. ©2014 Poultry Science Association Inc.

Effects of Friction and Plastic Deformation in Shock-Comminuted Damaged Rocks on Impact Heating

NASA Astrophysics Data System (ADS)

Kurosawa, Kosuke; Genda, Hidenori

2018-01-01

Hypervelocity impacts cause significant heating of planetary bodies. Such events are recorded by a reset of 40Ar-36Ar ages and/or impact melts. Here we investigate the influence of friction and plastic deformation in shock-generated comminuted rocks on the degree of impact heating using the iSALE shock-physics code. We demonstrate that conversion from kinetic to internal energy in the targets with strength occurs during pressure release, and additional heating becomes significant for low-velocity impacts (<10 km s-1). This additional heat reduces the impact-velocity thresholds required to heat the targets with the 0.1 projectile mass to temperatures for the onset of Ar loss and melting from 8 and 10 km s-1, respectively, for strengthless rocks to 2 and 6 km s-1 for typical rocks. Our results suggest that the impact conditions required to produce the unique features caused by impact heating span a much wider range than previously thought.

Cooption of heat shock regulatory system for anhydrobiosis in the sleeping chironomid Polypedilum vanderplanki

PubMed Central

Shagimardanova, Elena; Kozlova, Olga; Cherkasov, Alexander; Sutormin, Roman; Stepanova, Vita V.; Stupnikov, Alexey; Logacheva, Maria; Penin, Aleksey; Sogame, Yoichiro; Cornette, Richard; Tokumoto, Shoko; Miyata, Yugo; Gelfand, Mikhail S.; Gusev, Oleg

2018-01-01

Polypedilum vanderplanki is a striking and unique example of an insect that can survive almost complete desiccation. Its genome and a set of dehydration–rehydration transcriptomes, together with the genome of Polypedilum nubifer (a congeneric desiccation-sensitive midge), were recently released. Here, using published and newly generated datasets reflecting detailed transcriptome changes during anhydrobiosis, as well as a developmental series, we show that the TCTAGAA DNA motif, which closely resembles the binding motif of the Drosophila melanogaster heat shock transcription activator (Hsf), is significantly enriched in the promoter regions of desiccation-induced genes in P. vanderplanki, such as genes encoding late embryogenesis abundant (LEA) proteins, thioredoxins, or trehalose metabolism-related genes, but not in P. nubifer. Unlike P. nubifer, P. vanderplanki has double TCTAGAA sites upstream of the Hsf gene itself, which is probably responsible for the stronger activation of Hsf in P. vanderplanki during desiccation compared with P. nubifer. To confirm the role of Hsf in desiccation-induced gene activation, we used the Pv11 cell line, derived from P. vanderplanki embryo. After preincubation with trehalose, Pv11 cells can enter anhydrobiosis and survive desiccation. We showed that Hsf knockdown suppresses trehalose-induced activation of multiple predicted Hsf targets (including P. vanderplanki-specific LEA protein genes) and reduces the desiccation survival rate of Pv11 cells fivefold. Thus, cooption of the heat shock regulatory system has been an important evolutionary mechanism for adaptation to desiccation in P. vanderplanki. PMID:29463761

Heat shock proteins: the missing link between hormonal and reproductive factors and rheumatoid arthritis?

PubMed

da Silva, J A

1991-10-01

Epidemiologic data suggest a strong link between hormonal and reproductive factors and the incidence of rheumatoid arthritis. Of interest is a possible protective effect of oral contraceptives or estrogen replacement therapy against the development of rheumatoid arthritis. At least 1 pregnancy also appears to reduce the risk of this disease. It has been hypothesized that hormonal contraceptive use and pregnancy elicit the production of higher amounts of endogenous heat shock proteins, which, in turn, induce immunotolerance to subsequent exposure to the actual triggering agent of rheumatoid arthritis. A related possibility is that pregnant women are exposed to specific types of heat shock proteins produced by the fetus in high concentrations. Heat shock proteins are known to be the predominant antigens related to the induction of reactive arthritis. The production of some such proteins is dependent on sex hormones in a tissue-specific way and their concentrations are raised dramatically by stimulation with estrogen and progesterone. A possible mechanism for heat protein-induced immunotolerance would be the predominant stimulation of a suppressor T cell clone. More research on the pathogenesis of rheumatic diseases and the activity of sex hormones could result in the development of a vaccine against rheumatoid arthritis.

Linking physiological and cellular responses to thermal stress: β-adrenergic blockade reduces the heat shock response in fish.

PubMed

Templeman, Nicole M; LeBlanc, Sacha; Perry, Steve F; Currie, Suzanne

2014-08-01

When faced with stress, animals use physiological and cellular strategies to preserve homeostasis. We were interested in how these high-level stress responses are integrated at the level of the whole animal. Here, we investigated the capacity of the physiological stress response, and specifically the β-adrenergic response, to affect the induction of the cellular heat shock proteins, HSPs, following a thermal stress in vivo. We predicted that blocking β-adrenergic stimulation during an acute heat stress in the whole animal would result in reduced levels of HSPs in red blood cells (RBCs) of rainbow trout compared to animals where adrenergic signaling remained intact. We first determined that a 1 h heat shock at 25 °C in trout acclimated to 13 °C resulted in RBC adrenergic stimulation as determined by a significant increase in cell swelling, a hallmark of the β-adrenergic response. A whole animal injection with the β2-adrenergic antagonist, ICI-118,551, successfully reduced this heat-induced RBC swelling. The acute heat shock caused a significant induction of HSP70 in RBCs of 13 °C-acclimated trout as well as a significant increase in plasma catecholamines. When heat-shocked fish were treated with ICI-118,551, we observed a significant attenuation of the HSP70 response. We conclude that circulating catecholamines influence the cellular heat shock response in rainbow trout RBCs, demonstrating physiological/hormonal control of the cellular stress response.

Subset of heat-shock transcription factors required for the early response of Arabidopsis to excess light

PubMed Central

Jung, Hou-Sung; Crisp, Peter A.; Estavillo, Gonzalo M.; Cole, Benjamin; Hong, Fangxin; Mockler, Todd C.; Pogson, Barry J.; Chory, Joanne

2013-01-01

Sunlight provides energy for photosynthesis and is essential for nearly all life on earth. However, too much or too little light or rapidly fluctuating light conditions cause stress to plants. Rapid changes in the amount of light are perceived as a change in the reduced/oxidized (redox) state of photosynthetic electron transport components in chloroplasts. However, how this generates a signal that is relayed to changes in nuclear gene expression is not well understood. We modified redox state in the reference plant, Arabidopsis thaliana, using either excess light or low light plus the herbicide DBMIB (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone), a well-known inhibitor of photosynthetic electron transport. Modification of redox state caused a change in expression of a common set of about 750 genes, many of which are known stress-responsive genes. Among the most highly enriched promoter elements in the induced gene set were heat-shock elements (HSEs), known motifs that change gene expression in response to high temperature in many systems. We show that HSEs from the promoter of the ASCORBATE PEROXIDASE 2 (APX2) gene were necessary and sufficient for APX2 expression in conditions of excess light, or under low light plus the herbicide. We tested APX2 expression phenotypes in overexpression and loss-of-function mutants of 15 Arabidopsis A-type heat-shock transcription factors (HSFs), and identified HSFA1D, HSFA2, and HSFA3 as key factors regulating APX2 expression in diverse stress conditions. Excess light regulates both the subcellular location of HSFA1D and its biochemical properties, making it a key early component of the excess light stress network of plants. PMID:23918368

Electron heating in quasi-perpendicular shocks - A Monte Carlo simulation

NASA Technical Reports Server (NTRS)

Veltri, Pierluigi; Mangeney, Andre; Scudder, Jack D.

1990-01-01

To study the problem of electron heating in quasi-perpendicular shocks, under the combined effects of 'reversible' motion, in the shock electric potential and magnetic field, and wave-particle interactions a diffusion equation was derived, in the drift (adiabatic) approximation and it was solved by using a Monte Carlo method. The results show that most of the observations can be explained within this framework. The simulation has also definitively shown that the electron parallel temperature is determined by the dc electromagnetic field and not by any wave particle induced heating. Wave-particle interactions are effective in smoothing out the large gradients in phase space produced by the 'reversible' motion of the electrons, thus producing a 'cooling' of the electrons. Some constraints on the wave-particle interaction process may be obtained from a detailed comparison between the simulation and observations. In particular, it appears that the adiabatic approximation must be violated in order to explain the observed evolution of the perpendicular temperature.

Effect of temperature shock and inventory surprises on natural gas and heating oil futures returns.

PubMed

Hu, John Wei-Shan; Hu, Yi-Chung; Lin, Chien-Yu

2014-01-01

The aim of this paper is to examine the impact of temperature shock on both near-month and far-month natural gas and heating oil futures returns by extending the weather and storage models of the previous study. Several notable findings from the empirical studies are presented. First, the expected temperature shock significantly and positively affects both the near-month and far-month natural gas and heating oil futures returns. Next, significant temperature shock has effect on both the conditional mean and volatility of natural gas and heating oil prices. The results indicate that expected inventory surprises significantly and negatively affects the far-month natural gas futures returns. Moreover, volatility of natural gas futures returns is higher on Thursdays and that of near-month heating oil futures returns is higher on Wednesdays than other days. Finally, it is found that storage announcement for natural gas significantly affects near-month and far-month natural gas futures returns. Furthermore, both natural gas and heating oil futures returns are affected more by the weighted average temperature reported by multiple weather reporting stations than that reported by a single weather reporting station.

Effect of Temperature Shock and Inventory Surprises on Natural Gas and Heating Oil Futures Returns

PubMed Central

Hu, John Wei-Shan; Lin, Chien-Yu

2014-01-01

The aim of this paper is to examine the impact of temperature shock on both near-month and far-month natural gas and heating oil futures returns by extending the weather and storage models of the previous study. Several notable findings from the empirical studies are presented. First, the expected temperature shock significantly and positively affects both the near-month and far-month natural gas and heating oil futures returns. Next, significant temperature shock has effect on both the conditional mean and volatility of natural gas and heating oil prices. The results indicate that expected inventory surprises significantly and negatively affects the far-month natural gas futures returns. Moreover, volatility of natural gas futures returns is higher on Thursdays and that of near-month heating oil futures returns is higher on Wednesdays than other days. Finally, it is found that storage announcement for natural gas significantly affects near-month and far-month natural gas futures returns. Furthermore, both natural gas and heating oil futures returns are affected more by the weighted average temperature reported by multiple weather reporting stations than that reported by a single weather reporting station. PMID:25133233

Different mechanisms are involved in the transcriptional activation by yeast heat shock transcription factor through two different types of heat shock elements.

PubMed

Hashikawa, Naoya; Yamamoto, Noritaka; Sakurai, Hiroshi

2007-04-06

The hydrophobic repeat is a conserved structural motif of eukaryotic heat shock transcription factor (HSF) that enables HSF to form a homotrimer. Homotrimeric HSF binds to heat shock elements (HSEs) consisting of three inverted repeats of the sequence nGAAn. Sequences consisting of four or more nGAAn units are bound cooperatively by two HSF trimers. We show that in Saccharomyces cerevisiae cells oligomerization-defective Hsf1 is not able to bind HSEs with three units and is not extensively phosphorylated in response to stress; it is therefore unable to activate genes containing this type of HSE. Several lines of evidence indicate that oligomerization is a prerequisite for stress-induced hyperphosphorylation of Hsf1. In contrast, oligomerization and hyperphosphorylation are not necessary for gene activation via HSEs with four units. Intragenic suppressor screening of oligomerization-defective hsf1 showed that an interface between adjacent DNA-binding domains is important for the binding of Hsf1 to the HSE. We suggest that Saccharomyces cerevisiae HSEs with different structures are regulated differently; HSEs with three units require Hsf1 to be both oligomerized and hyperphosphorylated, whereas HSEs with four or more units do not require either.

Isoform composition and stoichiometry of the approx. 90-kDa heat shock protein associated with glucocorticoid receptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendel, D.B.; Orti, E.

1988-05-15

The authors observed that the approx. 90-kDa non-steroid-binding component of nonactivated glucocorticoid receptors purified from WEHI-7 mouse thymoma cells (which has been identified as the approx. 90-kDa heat shock protein) consistently migrates as a doublet during polyacrylamide gel electrophoresis under denaturing and reducing conditions. It has recently been reported that murine Meth A cells contain a tumor-specific transplantation antigen (TSTA) which is related or identical to the approx. 90-kDa heat shock protein. The observation that TSTA and the approx. 90-kDa heat shock protein isolated from these cells exists as two isoforms of similar molecular mass and charge has suggested thatmore » the doublet observed is also due to the existence of two isoforms. They have therefore conducted this study to determine whether TSTA and the approx. 90-kDa component of glucocorticoid receptors are indeed related, to establish whether the receptor preferentially binds one isoform of the approx. 90-kDa heat shock protein, and to investigate the stoichiometry of the nonactivated receptor complex. They used the BuGr1 and AC88 monoclonal antibodies to purify, respectively, receptor-associated and free approx. 90-kDa heat shock protein from WEHI-7 cells grown for 48 h with (/sup 35/S)methionine to metabolically label proteins to steady state. The long-term metabolic labeling approach has also enabled them to directly determine that the purified non-activated glucocorticoid receptor contains a single steroid-binding protein and two approx. 90-kDa non-steroid-binding subunits. The consistency with which a approx. 1:2 stoichiometric ratio of steroid binding to approx. 90-kDa protein is observed supports the view that the approx. 90-kDa heat shock protein is a true component of nonactivated glucocorticoid-receptor complexes.« less

Proteome changes in rainbow trout (Oncorhynchus mykiss) fertilized eggs as an effect of triploidization heat-shock treatment.

PubMed

Babaheydari, Samad Bahrami; Keyvanshokooh, Saeed; Dorafshan, Salar; Johari, Seyed Ali

2016-03-01

The aim of the present study was to explore proteome changes in rainbow trout (Oncorhynchus mykiss) fertilized eggs as an effect of triploidization heat-shock treatment. Eggs and milt were taken from eight females and six males. The gametes were pooled to minimize the individual differences. After insemination, the eggs were incubated at 10°C for 10min. Half of the fertilized eggs were then subjected to heat shock for 10min submerged in a 28°C water bath to induce triploidy. The remainder were incubated normally and used as diploid controls. Three batches of eggs were randomly selected from each group and were incubated at 10-11°C under the same environmental conditions in hatchery troughs until the fry stage. Triplicate samples of 30 eggs (10 eggs per trough) from each group were randomly selected 1.5h post-fertilization for proteome extraction. Egg proteins were analyzed using two-dimensional electrophoresis (2-DE) and MALDI-TOF/TOF mass spectrometry. Based on the results from the statistical analyses, 15 protein spots were found to decrease significantly in abundance in heat-shock treated group and were selected for identification. Out of 15 protein spots showing altered abundance, 14 spots were successfully identified. All of the egg proteins identified in our study were related to vitellogenin (vtg). Decreased abundance of vitellogenin in heat-shock treated eggs in our study may either be explained by (i) higher utilization of vtg as an effect of increased cell size in triploids or (ii) changed metabolism in response to heat-shock stress and (iii) diffusion of vtg through chorion due to incidence of egg shell damage. Decreased abundance of vitellogenin in heat-shock treated eggs was associated with reduced early survival rates and lowered growth performance of triploid fish. Copyright © 2016 Elsevier B.V. All rights reserved.

Changes in the regulation of heat shock gene expression in neuronal cell differentiation.

PubMed

Oza, Jay; Yang, Jingxian; Chen, Kuang Yu; Liu, Alice Y-C

2008-01-01

Neuronal differentiation of the NG108-15 neuroblastoma-glioma hybrid cells is accompanied by a marked attenuation in the heat shock induction of the Hsp70-firefly luciferase reporter gene activity. Analysis of the amount and activation of heat shock factor 1, induction of mRNA(hsp), and the synthesis and accumulation of heat shock proteins (HSPs) in the undifferentiated and differentiated cells suggest a transcriptional mechanism for this attenuation. Concomitant with a decreased induction of the 72-kDa Hsp70 protein in the differentiated cells, there is an increased abundance of the constitutive 73-kDa Hsc70, a protein known to function in vesicle trafficking. Assessment of sensitivity of the undifferentiated and differentiated cells against stress-induced cell death reveals a significantly greater vulnerability of the differentiated cells toward the cytotoxic effects of arsenite and glutamate/glycine. This study shows that changes in regulation of the HSP and HSC proteins are components of the neuronal cell differentiation program and that the attenuated induction of HSPs likely contributes to neuronal vulnerability whereas the increased expression of Hsc70 likely has a role in neural-specific functions.

Heat shock of Escherichia coli increases binding of dnaK (the hsp70 homolog) to polypeptides by promoting its phosphorylation.

PubMed Central

Sherman, M Y; Goldberg, A L

1993-01-01

The "molecular chaperone", dnaK, is induced in Escherichia coli upon heat shock and promotes ATP-dependent refolding or degradation of damaged proteins. When cells were grown at 25 degrees C and disrupted, a small fraction of the dnaK bound to affinity columns containing unfolded polypeptides (e.g., a fusion protein named CRAG or casein) and could be dissociated by ATP-Mg2+. After shifting cells to 42 degrees C for 30 min, up to 5-fold more dnaK bound to these columns than after growth at 25 degrees C. This enhanced binding capacity was reversed after shifting cells back to 25 degrees C. It resulted from a covalent modification, which decreases dnaK's electrophoretic mobility and isoelectric point. This modification appears to be phosphorylation; after treatment with phosphatases, the ATP-eluted dnaK resembled the predominant form in electrophoretic and binding properties. In addition, after incubating cells with [32P]orthophosphate at 42 degrees C, the 32P-labeled dnaK bound quantitatively to the CRAG column, unlike the nonlabeled protein. Thus, the phosphorylated dnaK is a special form of the chaperone with enhanced affinity for unfolded proteins. Its accumulation at high temperatures may account for dnaK's function as the "cellular thermometer." Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 PMID:8378342

Heat shock and prolonged heat stress attenuate neurotoxin and sporulation gene expression in group I Clostridium botulinum strain ATCC 3502

PubMed Central

Selby, Katja; Mascher, Gerald; Somervuo, Panu; Korkeala, Hannu

2017-01-01

Foodborne pathogenic bacteria are exposed to a number of environmental stresses during food processing, storage, and preparation, and in the human body. In order to improve the safety of food, the understanding of molecular stress response mechanisms foodborne pathogens employ is essential. Many response mechanisms that are activated during heat shock may cross-protect bacteria against other environmental stresses. To better understand the molecular mechanisms Clostridium botulinum, the causative agent of botulism, utilizes during acute heat stress and during adaptation to stressfully high temperature, the C. botulinum Group I strain ATCC 3502 was grown in continuous culture at 39°C and exposed to heat shock at 45°C, followed by prolonged heat stress at 45°C to allow adaptation of the culture to the high temperature. Growth in continuous culture was performed to exclude secondary growth phase effects or other environmental impacts on bacterial gene transcription. Changes in global gene expression profiles were studied using DNA microarray hybridization. During acute heat stress, Class I and III heat shock genes as well as members of the SOS regulon were activated. The neurotoxin gene botA and genes encoding the neurotoxin-associated proteins were suppressed throughout the study. Prolonged heat stress led to suppression of the sporulation machinery whereas genes related to chemotaxis and motility were activated. Induced expression of a large proportion of prophage genes was detected, suggesting an important role of acquired genes in the stress resistance of C. botulinum. Finally, changes in the expression of a large number of genes related to carbohydrate and amino acid metabolism indicated remodeling of the cellular metabolism. PMID:28464023

Heat shock and prolonged heat stress attenuate neurotoxin and sporulation gene expression in group I Clostridium botulinum strain ATCC 3502.

PubMed

Selby, Katja; Mascher, Gerald; Somervuo, Panu; Lindström, Miia; Korkeala, Hannu

2017-01-01

Foodborne pathogenic bacteria are exposed to a number of environmental stresses during food processing, storage, and preparation, and in the human body. In order to improve the safety of food, the understanding of molecular stress response mechanisms foodborne pathogens employ is essential. Many response mechanisms that are activated during heat shock may cross-protect bacteria against other environmental stresses. To better understand the molecular mechanisms Clostridium botulinum, the causative agent of botulism, utilizes during acute heat stress and during adaptation to stressfully high temperature, the C. botulinum Group I strain ATCC 3502 was grown in continuous culture at 39°C and exposed to heat shock at 45°C, followed by prolonged heat stress at 45°C to allow adaptation of the culture to the high temperature. Growth in continuous culture was performed to exclude secondary growth phase effects or other environmental impacts on bacterial gene transcription. Changes in global gene expression profiles were studied using DNA microarray hybridization. During acute heat stress, Class I and III heat shock genes as well as members of the SOS regulon were activated. The neurotoxin gene botA and genes encoding the neurotoxin-associated proteins were suppressed throughout the study. Prolonged heat stress led to suppression of the sporulation machinery whereas genes related to chemotaxis and motility were activated. Induced expression of a large proportion of prophage genes was detected, suggesting an important role of acquired genes in the stress resistance of C. botulinum. Finally, changes in the expression of a large number of genes related to carbohydrate and amino acid metabolism indicated remodeling of the cellular metabolism.

Heat Shock Protein 70 Modulates Influenza A Virus Polymerase Activity*

PubMed Central

Manzoor, Rashid; Kuroda, Kazumichi; Yoshida, Reiko; Tsuda, Yoshimi; Fujikura, Daisuke; Miyamoto, Hiroko; Kajihara, Masahiro; Kida, Hiroshi; Takada, Ayato

2014-01-01

The role of heat shock protein 70 (Hsp70) in virus replication has been discussed for many viruses. The known suppressive role of Hsp70 in influenza virus replication is based on studies conducted in cells with various Hsp70 expression levels. In this study, we determined the role of Hsp70 in influenza virus replication in HeLa and HEK293T cells, which express Hsp70 constitutively. Co-immunoprecipitation and immunofluorescence studies revealed that Hsp70 interacted with PB2 or PB1 monomers and PB2/PB1 heterodimer but not with the PB1/PA heterodimer or PB2/PB1/PA heterotrimer and translocated into the nucleus with PB2 monomers or PB2/PB1 heterodimers. Knocking down Hsp70 resulted in reduced virus transcription and replication activities. Reporter gene assay, immunofluorescence assay, and Western blot analysis of nuclear and cytoplasmic fractions from infected cells demonstrated that the increase in viral polymerase activity during the heat shock phase was accompanied with an increase in Hsp70 and viral polymerases levels in the nuclei, where influenza virus replication takes place, whereas a reduction in viral polymerase activity was accompanied with an increase in cytoplasmic relocation of Hsp70 along with viral polymerases. Moreover, significantly higher levels of viral genomic RNA (vRNA) were observed during the heat shock phase than during the recovery phase. Overall, for the first time, these findings suggest that Hsp70 may act as a chaperone for influenza virus polymerase, and the modulatory effect of Hsp70 appears to be a sequel of shuttling of Hsp70 between nuclear and cytoplasmic compartments. PMID:24474693

Suppression of polyglutamine protein toxicity by co-expression of a heat-shock protein 40 and a heat-shock protein 110

PubMed Central

Kuo, Y; Ren, S; Lao, U; Edgar, B A; Wang, T

2013-01-01

A network of heat-shock proteins mediates cellular protein homeostasis, and has a fundamental role in preventing aggregation-associated neurodegenerative diseases. In a Drosophila model of polyglutamine (polyQ) disease, the HSP40 family protein, DNAJ-1, is a superior suppressor of toxicity caused by the aggregation of polyQ containing proteins. Here, we demonstrate that one specific HSP110 protein, 70 kDa heat-shock cognate protein cb (HSC70cb), interacts physically and genetically with DNAJ-1 in vivo, and that HSC70cb is necessary for DNAJ-1 to suppress polyglutamine-induced cell death in Drosophila. Expression of HSC70cb together with DNAJ-1 significantly enhanced the suppressive effects of DNAJ-1 on polyQ-induced neurodegeneration, whereas expression of HSC70cb alone did not suppress neurodegeneration in Drosophila models of either general polyQ disease or Huntington's disease. Furthermore, expression of a human HSP40, DNAJB1, together with a human HSP110, APG-1, protected cells from polyQ-induced neural degeneration in flies, whereas expression of either component alone had little effect. Our data provide a functional link between HSP40 and HSP110 in suppressing the cytotoxicity of aggregation-prone proteins, and suggest that HSP40 and HSP110 function together in protein homeostasis control. PMID:24091676

Baculovirus IE2 Stimulates the Expression of Heat Shock Proteins in Insect and Mammalian Cells to Facilitate Its Proper Functioning.

PubMed

Tung, Hsuan; Wei, Sung-Chan; Lo, Huei-Ru; Chao, Yu-Chan

2016-01-01

Baculoviruses have gained popularity as pest control agents and for protein production in insect systems. These viruses are also becoming popular for gene expression, tissue engineering and gene therapy in mammalian systems. Baculovirus infection triggers a heat shock response, and this response is crucial for its successful infection of host insect cells. However, the viral protein(s) or factor(s) that trigger this response are not yet clear. Previously, we revealed that IE2-an early gene product of the baculovirus-could form unique nuclear bodies for the strong trans-activation of various promoters in mammalian cells. Here, we purified IE2 nuclear bodies from Vero E6 cells and investigated the associated proteins by using mass spectrometry. Heat shock proteins (HSPs) were found to be one of the major IE2-associated proteins. Our experiments show that HSPs are greatly induced by IE2 and are crucial for the trans-activation function of IE2. Interestingly, blocking both heat shock protein expression and the proteasome pathway preserved the IE2 protein and its nuclear body structure, and revived its function. These observations reveal that HSPs do not function directly to assist the formation of the nuclear body structure, but may rather protect IE2 from proteasome degradation. Aside from functional studies in mammalian cells, we also show that HSPs were stimulated and required to determine IE2 protein levels, in insect cells infected with baculovirus. Upon inhibiting the expression of heat shock proteins, baculovirus IE2 was substantially suppressed, resulting in a significantly suppressed viral titer. Thus, we demonstrate a unique feature in that IE2 can function in both insect and non-host mammalian cells to stimulate HSPs, which may be associated with IE2 stabilization and lead to the protection of the its strong gene activation function in mammalian cells. On the other hand, during viral infection in insect cells, IE2 could also strongly stimulate HSPs and

Apoptosis in response to heat stress is positively associated with heat-shock protein 90 expression in chicken myocardial cells in vitro.

PubMed

Zhang, Xiao-Hui; Wu, Hong; Tang, Shu; Li, Qiao-Ning; Xu, Jiao; Zhang, Miao; Su, Ya-Nan; Yin, Bin; Zhao, Qi-Ling; Kemper, Nicole; Hartung, Joerg; Bao, En-Dong

2017-06-30

To determine heat-shock protein (Hsp)90 expression is connected with cellular apoptotic response to heat stress and its mechanism, chicken ( Gallus gallus ) primary myocardial cells were treated with the Hsp90 promoter, aspirin, and its inhibitor, geldanamycin (GA), before heat stress. Cellular viability, heat-stressed apoptosis and reactive oxygen species level under different treatments were measured, and the expression of key proteins of the signaling pathway related to Hsp90 and their colocalization with Hsp90 were detected. The results showed that aspirin treatment increased the expression of protein kinase B (Akt), the signal transducer and activator of transcription (STAT)-3 and p-IKKα/β and the colocalization of Akt and STAT-3 with Hsp90 during heat stress, which was accompanied by improved viability and low apoptosis. GA significantly inhibited Akt expression and p-IKKα/β level, but not STAT-3 quantity, while the colocalization of Akt and STAT-3 with Hsp90 was weakened, followed by lower cell viability and higher apoptosis. Aspirin after GA treatment partially improved the stress response and apoptosis rate of tested cells caused by the recovery of Akt expression and colocalization, rather than the level of STAT-3 (including its co-localization with Hsp90) and p-IKKα/β. Therefore, Hsp90 expression has a positive effect on cellular capacity to resist heat-stressed injury and apoptosis. Moreover, inhibition of Hsp90 before stress partially attenuated its positive effects.

Role of charred wood, heat-shock and light in germination of postfire phrygana species from the eastern Mediterranean Basin

USGS Publications Warehouse

Keeley, Jon E.; Babr-Keeley, Melanie

1999-01-01

Seeds of 22 species collected from recently burned phrygana were tested for their response to fire-type cues of charred wood and heat-shock. All Cistus species were stimulated by brief heat-shock, as shown in previous studies; however, none responded to charred wood. Only one of the 22 species was stimulated by charred wood, and only in dark-inhibited seeds, and this response did not occur in the light. The lack of charred-wood-induced germination is in contrast to the substantial proportion of species with this germination response reported for mediterranean-type vegetation in California, the Cape region of South Africa, and Western Australia. Phrygana has many species with heat-shock-stimulated germination, primarily in the Fabaceae and Cistaceae. This germination cue is widespread in these two families, thus, the presence of heat-shock-stimulated germination is a result of homologous, rather than covergent, adaptations in mediterranean-climate ecosystems. Germination response to light was not randomly distributed with respect to fire-type response. Heat-shock-stimulated species were almost uniformly light neutral, in contrast to more opportunistic colonizing species with non-refractory seeds, in which half of the species responded positively or negatively to light.

Short-term heat shock affects the course of immune response in Galleria mellonella naturally infected with the entomopathogenic fungus Beauveria bassiana.

PubMed

Vertyporokh, Lidiia; Taszłow, Paulina; Samorek-Pieróg, Małgorzata; Wojda, Iwona

2015-09-01

We aimed to investigate how exposition of infected insects to short-term heat shock affects the biochemical and molecular aspects of their immune response. Galleria mellonella larvae were exposed to 43°C for 15min, at the seventy second hour after natural infection with entomopathogenic fungus Beauveria bassiana. As a result, both qualitative and quantitative changes in hemolymph protein profiles, and among them infection-induced changes in the amount of apolipophorin III (apoLp-III), were observed. Heat shock differently affects the expression of the tested immune-related genes. It transiently inhibits expression of antifungal peptides gallerimycin and galiomicin in both the fat body and hemocytes of infected larvae. The same, although to a lesser extent, concerned apoLp-III gene expression and was observed directly after heat shock. Nevertheless, in larvae that had recovered from heat shock, apoLp-III expression was higher in comparison to unshocked larvae in the fat body but not in hemocytes, which was consistent with the higher amount of this protein detected in the hemolymph of the infected, shocked larvae. Furthermore, lysozyme-type activity was higher directly after heat shock, while antifungal activity was significantly higher also in larvae that had recovered from heat shock, in comparison to the respective values in their non-shocked, infected counterparts. These results show how changes in the external temperature modulate the immune response of G. mellonella suffering from infection with its natural pathogen B. bassiana. Copyright © 2015 Elsevier Inc. All rights reserved.

Thermoprotection of synaptic transmission in a Drosophila heat shock factor mutant is accompanied by increased expression of Hsp83 and DnaJ-1.

PubMed

Neal, Scott J; Karunanithi, Shanker; Best, Adrienne; So, Anthony Ken-Choy; Tanguay, Robert M; Atwood, Harold L; Westwood, J Timothy

2006-05-16

In Drosophila larvae, acquired synaptic thermotolerance after heat shock has previously been shown to correlate with the induction of heat shock proteins (Hsps) including HSP70. We tested the hypothesis that synaptic thermotolerance would be significantly diminished in a temperature-sensitive strain (Drosophila heat shock factor mutant hsf4), which has been reported not to be able to produce inducible Hsps in response to heat shock. Contrary to our hypothesis, considerable thermoprotection was still observed at hsf4 larval synapses after heat shock. To investigate the cause of this thermoprotection, we conducted DNA microarray experiments to identify heat-induced transcript changes in these organisms. Transcripts of the hsp83, dnaJ-1 (hsp40), and glutathione-S-transferase gstE1 genes were significantly upregulated in hsf4 larvae after heat shock. In addition, increases in the levels of Hsp83 and DnaJ-1 proteins but not in the inducible form of Hsp70 were detected by Western blot analysis. The mode of heat shock administration differentially affected the relative transcript and translational changes for these chaperones. These results indicate that the compensatory upregulation of constitutively expressed Hsps, in the absence of the synthesis of the major inducible Hsp, Hsp70, could still provide substantial thermoprotection to both synapses and the whole organism.

Global Aeroheating Measurements of Shock-Shock Interactions on a Swept Cylinder

NASA Technical Reports Server (NTRS)

Mason, Michelle L.; Berry, Scott A.

2015-01-01

The effects of fin leading-edge radius and sweep angle on peak heating rates due to shock-shock interactions were investigated in the NASA Langley Research Center 20-Inch Mach 6 Air Tunnel. The cylindrical leading-edge fin models, with radii varied from 0.25 to 0.75 inches, represent wings or struts on hypersonic vehicles. A 9deg wedge generated a planar oblique shock at 16.7deg. to the flow that intersected the fin bow shock, producing a shock-shock interaction that impinged on the fin leading edge. The fin sweep angle was varied from 0deg (normal to the free-stream) to 15deg and 25deg swept forward. These cases were chosen to explore three characterized shock-shock interaction types. Global temperature data were obtained from the surface of the fused silica fins using phosphor thermography. Metal oil flow models with the same geometries as the fused silica models were used to visualize the streamline patterns for each angle of attack. High-speed zoom-schlieren videos were recorded to show the features and any temporal unsteadiness of the shock-shock interactions. The temperature data were analyzed using a one-dimensional semi-infinite method, as well as one- and two-dimensional finite-volume methods. These results were compared to determine the proper heat transfer analysis approach to minimize errors from lateral heat conduction due to the presence of strong surface temperature gradients induced by the shock interactions. The general trends in the leading-edge heat transfer behavior were similar for each explored shock-shock interaction type regardless of the leading-edge radius. However, the dimensional peak heat transfer coefficient augmentation increased with decreasing leading-edge radius. The dimensional peak heat transfer output from the two-dimensional code was about 20% higher than the value from a standard, semi-infinite one-dimensional method.

Dynamic control of Hsf1 during heat shock by a chaperone switch and phosphorylation

PubMed Central

Zheng, Xu; Krakowiak, Joanna; Patel, Nikit; Beyzavi, Ali; Ezike, Jideofor; Khalil, Ahmad S; Pincus, David

2016-01-01

Heat shock factor (Hsf1) regulates the expression of molecular chaperones to maintain protein homeostasis. Despite its central role in stress resistance, disease and aging, the mechanisms that control Hsf1 activity remain unresolved. Here we show that in budding yeast, Hsf1 basally associates with the chaperone Hsp70 and this association is transiently disrupted by heat shock, providing the first evidence that a chaperone repressor directly regulates Hsf1 activity. We develop and experimentally validate a mathematical model of Hsf1 activation by heat shock in which unfolded proteins compete with Hsf1 for binding to Hsp70. Surprisingly, we find that Hsf1 phosphorylation, previously thought to be required for activation, in fact only positively tunes Hsf1 and does so without affecting Hsp70 binding. Our work reveals two uncoupled forms of regulation - an ON/OFF chaperone switch and a tunable phosphorylation gain - that allow Hsf1 to flexibly integrate signals from the proteostasis network and cell signaling pathways. DOI: http://dx.doi.org/10.7554/eLife.18638.001 PMID:27831465

Sodium hydrosulfide induces systemic thermotolerance to strawberry plants through transcriptional regulation of heat shock proteins and aquaporin

PubMed Central

2014-01-01

Background Temperature extremes represent an important limiting factor to plant growth and productivity. The present study evaluated the effect of hydroponic pretreatment of strawberry (Fragaria x ananassa cv. ‘Camarosa’) roots with an H2S donor, sodium hydrosulfide (NaHS; 100 μM for 48 h), on the response of plants to acute heat shock treatment (42°C, 8 h). Results Heat stress-induced phenotypic damage was ameliorated in NaHS-pretreated plants, which managed to preserve higher maximum photochemical PSII quantum yields than stressed plants. Apparent mitigating effects of H2S pretreatment were registered regarding oxidative and nitrosative secondary stress, since malondialdehyde (MDA), H2O2 and nitric oxide (NO) were quantified in lower amounts than in heat-stressed plants. In addition, NaHS pretreatment preserved ascorbate/glutathione homeostasis, as evidenced by lower ASC and GSH pool redox disturbances and enhanced transcription of ASC (GDH) and GSH biosynthetic enzymes (GS, GCS), 8 h after heat stress imposition. Furthermore, NaHS root pretreatment resulted in induction of gene expression levels of an array of protective molecules, such as enzymatic antioxidants (cAPX, CAT, MnSOD, GR), heat shock proteins (HSP70, HSP80, HSP90) and aquaporins (PIP). Conclusion Overall, we propose that H2S root pretreatment activates a coordinated network of heat shock defense-related pathways at a transcriptional level and systemically protects strawberry plants from heat shock-induced damage. PMID:24499299

Heat shock and thermotolerance of Escherichia coli O157:H7 in a model beef gravy system and ground beef.

PubMed

Juneja, V K; Klein, P G; Marmer, B S

1998-04-01

Duplicate beef gravy or ground beef samples inoculated with a suspension of a four-strain cocktail of Escherichia coli O157:H7 were subjected to sublethal heating at 46 degrees C for 15-30 min, and then heated to a final internal temperature of 60 degrees C. Survivor curves were fitted using a linear model that incorporated a lag period (TL), and D-values and 'time to a 4D inactivation' (T4D) were calculated. Heat-shocking allowed the organism to survive longer than non-heat-shocked cells; the T4D values at 60 degrees C increased 1.56- and 1.50-fold in beef gravy and ground beef, respectively. In ground beef stored at 4 degrees C, thermotolerance was lost after storage for 14 h. However, heat-shocked cells appeared to maintain their thermotolerance for at least 24 h in ground beef held to 15 or 28 degrees C. A 25 min heat shock at 46 degrees C in beef gravy resulted in an increase in the levels of two proteins with apparent molecular masses of 60 and 69 kDa. These two proteins were shown to be immunologically related to GroEL and DnaK, respectively. Increased heat resistance due to heat shock must be considered while designing thermal processes to assure the microbiological safety of thermally processed foods.

The stress protein heat shock cognate 70 (Hsc70) inhibits the Transient Receptor Potential Vanilloid type 1 (TRPV1) channel.

PubMed

Iftinca, Mircea; Flynn, Robyn; Basso, Lilian; Melo, Helvira; Aboushousha, Reem; Taylor, Lauren; Altier, Christophe

2016-01-01

Specialized cellular defense mechanisms prevent damage from chemical, biological, and physical hazards. The heat shock proteins have been recognized as key chaperones that maintain cell survival against a variety of exogenous and endogenous stress signals including noxious temperature. However, the role of heat shock proteins in nociception remains poorly understood. We carried out an expression analysis of the constitutively expressed 70 kDa heat-shock cognate protein, a member of the stress-induced HSP70 family in lumbar dorsal root ganglia from a mouse model of Complete Freund's Adjuvant-induced chronic inflammatory pain. We used immunolabeling of dorsal root ganglion neurons, behavioral analysis and patch clamp electrophysiology in both dorsal root ganglion neurons and HEK cells transfected with Hsc70 and Transient Receptor Potential Channels to examine their functional interaction in heat shock stress condition. We report an increase in protein levels of Hsc70 in mouse dorsal root ganglia, 3 days post Complete Freund's Adjuvant injection in the hind paw. Immunostaining of Hsc70 was observed in most of the dorsal root ganglion neurons, including the small size nociceptors immunoreactive to the TRPV1 channel. Standard whole-cell patch-clamp technique was used to record Transient Receptor Potential Vanilloid type 1 current after exposure to heat shock. We found that capsaicin-evoked currents are inhibited by heat shock in dorsal root ganglion neurons and transfected HEK cells expressing Hsc70 and TRPV1. Blocking Hsc70 with matrine or spergualin compounds prevented heat shock-induced inhibition of the channel. We also found that, in contrast to TRPV1, both the cold sensor channels TRPA1 and TRPM8 were unresponsive to heat shock stress. Finally, we show that inhibition of TRPV1 depends on the ATPase activity of Hsc70 and involves the rho-associated protein kinase. Our work identified Hsc70 and its ATPase activity as a central cofactor of TRPV1 channel function

Heat Shock Factor 1 Deficiency Affects Systemic Body Temperature Regulation.

PubMed

Ingenwerth, Marc; Noichl, Erik; Stahr, Anna; Korf, Horst-Werner; Reinke, Hans; von Gall, Charlotte

2016-01-01

Heat shock factor 1 (HSF1) is a ubiquitous heat-sensitive transcription factor that mediates heat shock protein transcription in response to cellular stress, such as increased temperature, in order to protect the organism against misfolded proteins. In this study, we analysed the effect of HSF1 deficiency on core body temperature regulation. Body temperature, locomotor activity, and food consumption of wild-type mice and HSF1-deficient mice were recorded. Prolactin and thyroid-stimulating hormone levels were measured by ELISA. Gene expression in brown adipose tissue was analysed by quantitative real-time PCR. Hypothalamic HSF1 and its co-localisation with tyrosine hydroxylase was analysed using confocal laser scanning microscopy. HSF1-deficient mice showed an increase in core body temperature (hyperthermia), decreased overall locomotor activity, and decreased levels of prolactin in pituitary and blood plasma reminiscent of cold adaptation. HSF1 could be detected in various hypothalamic regions involved in temperature regulation, suggesting a potential role of HSF1 in hypothalamic thermoregulation. Moreover, HSF1 co-localises with tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis, suggesting a potential role of HSF1 in the hypothalamic control of prolactin release. In brown adipose tissue, levels of prolactin receptor and uncoupled protein 1 were increased in HSF1-deficient mice, consistent with an up-regulation of heat production. Our data suggest a role of HSF1 in systemic thermoregulation. © 2015 S. Karger AG, Basel.

Analysis of transactivation potential of rice (Oryza sativa L.) heat shock factors.

PubMed

Lavania, Dhruv; Dhingra, Anuradha; Grover, Anil

2018-06-01

Based on yeast one-hybrid assays, we show that the presence of C-terminal AHA motifs is not a prerequisite for transactivation potential in rice heat shock factors. Transcriptional activation or transactivation (TA) of heat stress responsive genes takes place by binding of heat shock factors (Hsfs) to heat shock elements. Analysis of TA potential of thirteen rice (Oryza sativa L.) Hsfs (OsHsfs) carried out in this study by yeast one-hybrid assay showed that OsHsfsA3 possesses strong TA potential while OsHsfs A1a, A2a, A2b, A4a, A4d, A5, A7b, B1, B2a, B2b, B2c and B4d lack TA potential. From a near complete picture of TA potential of the OsHsf family (comprising of 25 members) emerging from this study and an earlier report from our group (Mittal et al. in FEBS J 278(17):3076-3085, 2011), it is concluded that (1) overall, six OsHsfs, namely A3, A6a, A6b, A8, C1a and C1b possess TA potential; (2) four class A OsHsfs, namely A3, A6a, A6b and A8 have TA potential out of which A6a and A6b contain AHA motifs while A3 and A8 lack AHA motifs; (3) nine class A OsHsfs, namely A1a, A2a, A2b, A2e, A4a, A4d, A5, A7a and A7b containing AHA motif(s) lack TA function in the yeast assay system; (4) all class B OsHsfs lack AHA motifs and TA potential (B4a not analyzed) and (5) though all class C OsHsf members lack AHA motifs, two members C1a and C1b possess TA function, while one member C2a lacks TA potential (C2b not analyzed). Thus, the presence or absence of AHA motif is possibly not the only factor determining TA potential of OsHsfs. Our findings will help to identify the transcriptional activators of rice heat shock response.

Sensing the heat stress by Mammalian cells.

PubMed

Cates, Jordan; Graham, Garrett C; Omattage, Natalie; Pavesich, Elizabeth; Setliff, Ian; Shaw, Jack; Smith, Caitlin Lee; Lipan, Ovidiu

2011-08-11

The heat-shock response network controls the adaptation and survival of the cell against environmental stress. This network is highly conserved and is connected with many other signaling pathways. A key element of the heat-shock network is the heat-shock transcription factor-1 (HSF), which is transiently activated by elevated temperatures. HSF translocates to the nucleus upon elevated temperatures, forming homotrimeric complexes. The HSF homotrimers bind to the heat shock element on the DNA and control the expression of the hsp70 gene. The Hsp70 proteins protect cells from thermal stress. Thermal stress causes the unfolding of proteins, perturbing thus the pathways under their control. By binding to these proteins, Hsp70 allows them to refold and prevents their aggregation. The modulation of the activity of the hsp70-promoter by the intensity of the input stress is thus critical for cell's survival. The promoter activity starts from a basal level and rapidly increases once the stress is applied, reaches a maximum level and attenuates slowely back to the basal level. This phenomenon is the hallmark of many experimental studies and of all computational network analysis. The molecular construct used as a measure of the response to thermal stress is a Hsp70-GFP fusion gene transfected in Chinese hamster ovary (CHO) cells. The time profile of the GFP protein depends on the transient activity, Transient(t), of the heat shock system. The function Transient(t) depends on hsp70 promoter activity, transcriptional regulation and the translation initiation effects elicited by the heat stress. The GFP time profile is recorded using flow cytometry measurements, a technique that allows a quantitative measurement of the fluorescence of a large number of cells (104). The GFP responses to one and two heat shocks were measured for 261 conditions of different temperatures and durations. We found that: (i) the response of the cell to two consecutive shocks (i.e., no recovery time in

Small interfering RNA mediated Poly (ADP-ribose) Polymerase-1 inhibition upregulates the heat shock response in a murine fibroblast cell line

PubMed Central

2011-01-01

Poly (ADP-ribose) polymerase-1 (PARP-1) is a highly conserved multifunctional enzyme, and its catalytic activity is stimulated by DNA breaks. The activation of PARP-1 and subsequent depletion of nicotinamide adenine dinucleotide (NAD+) and adenosine triphosphate (ATP) contributes to significant cytotoxicity in inflammation of various etiologies. On the contrary, induction of heat shock response and production of heat shock protein 70 (HSP-70) is a cytoprotective defense mechanism in inflammation. Recent data suggests that PARP-1 modulates the expression of a number of cellular proteins at the transcriptional level. In this study, small interfering RNA (siRNA) mediated PARP-1 knockdown in murine wild-type fibroblasts augmented heat shock response as compared to untreated cells (as evaluated by quantitative analysis of HSP-70 mRNA and HSP-70 protein expression). These events were associated with increased DNA binding of the heat shock factor-1 (HSF-1), the major transcription factor of the heat shock response. Co-immunoprecipitation experiments in nuclear extracts of the wild type cells demonstrated that PARP-1directly interacted with HSF-1. These data demonstrate that, in wild type fibroblasts, PARP-1 plays a pivotal role in modulating the heat shock response both through direct interaction with HSF-1 and poly (ADP-ribosylation). PMID:21345219

τ kinases in the rat heat shock model: Possible implications for Alzheimer disease

PubMed Central

Shanavas, Alikunju; Papasozomenos, Sozos Ch.

2000-01-01

We have previously shown, by using the phosphate-dependent anti-τ antibodies Tau-1 and PHF-1, that heat shock induces rapid dephosphorylation of τ followed by hyperphosphorylation in female rats. In this study, we analyzed in forebrain homogenates from female Sprague–Dawley rats the activities of extracellular signal regulated kinase 1/2 (ERK1/2), c-Jun NH2-terminal kinase (JNK), glycogen synthase kinase-3β (GSK-3β), cyclin-dependent kinase 5 (Cdk5), cAMP-dependent protein kinase A (PKA), and Ca2+/calmodulin-dependent protein kinase II (CaMKII) at 0 (n = 5), 3 (n = 4), 6 (n = 5), and 12 (n = 5) h after heat shock and in non-heat-shocked controls (n = 5). Immunoprecipitation kinase assays at 0 h showed suppression of the activities of all kinases except of GSK-3β, which showed increased activity. At 3–6 h, the activities of ERK1/2, JNK, Cdk5, and GSK-3β toward selective substrates were increased; however, only JNK, Cdk5, and GSK-3β but not ERK1/2 were overactivated toward purified bovine τ. At 3–6 h, kinase assays specific for PKA and CaMKII showed no increased activity toward either τ or selective substrates. All of eight anti-τ antibodies tested showed dephosphorylation at 0 h and hyperphosphorylation at 3–6 h, except for 12E8, which showed hyperphosphorylation also at 0 h. Immunoblot analysis using activity-dependent antibodies against ERK1/2, JNK, and GSK-3β confirmed the above data. Increased activation and inhibition of kinases after heat shock were statistically significant in comparison with controls. Because τ is hyperphosphorylated in Alzheimer disease these findings suggest that JNK, GSK-3β, and Cdk5 may play a role in its pathogenesis. PMID:11121021

Heat Shock Response in Yeast Involves Changes in Both Transcription Rates and mRNA Stabilities

PubMed Central

Castells-Roca, Laia; García-Martínez, José; Moreno, Joaquín; Herrero, Enrique; Bellí, Gemma; Pérez-Ortín, José E.

2011-01-01

We have analyzed the heat stress response in the yeast Saccharomyces cerevisiae by determining mRNA levels and transcription rates for the whole transcriptome after a shift from 25°C to 37°C. Using an established mathematical algorithm, theoretical mRNA decay rates have also been calculated from the experimental data. We have verified the mathematical predictions for selected genes by determining their mRNA decay rates at different times during heat stress response using the regulatable tetO promoter. This study indicates that the yeast response to heat shock is not only due to changes in transcription rates, but also to changes in the mRNA stabilities. mRNA stability is affected in 62% of the yeast genes and it is particularly important in shaping the mRNA profile of the genes belonging to the environmental stress response. In most cases, changes in transcription rates and mRNA stabilities are homodirectional for both parameters, although some interesting cases of antagonist behavior are found. The statistical analysis of gene targets and sequence motifs within the clusters of genes with similar behaviors shows that both transcriptional and post-transcriptional regulons apparently contribute to the general heat stress response by means of transcriptional factors and RNA binding proteins. PMID:21364882

Evolution of Hsp70 Gene Expression: A Role for Changes in AT-Richness within Promoters

PubMed Central

Ma, Ronghui; Zhang, Bo; Kang, Le

2011-01-01

In disparate organisms adaptation to thermal stress has been linked to changes in the expression of genes encoding heat-shock proteins (Hsp). The underlying genetics, however, remain elusive. We show here that two AT-rich sequence elements in the promoter region of the hsp70 gene of the fly Liriomyza sativae that are absent in the congeneric species, Liriomyza huidobrensis, have marked cis-regulatory consequences. We studied the cis-regulatory consequences of these elements (called ATRS1 and ATRS2) by measuring the constitutive and heat-shock-induced luciferase luminescence that they drive in cells transfected with constructs carrying them modified, deleted, or intact, in the hsp70 promoter fused to the luciferase gene. The elements affected expression level markedly and in different ways: Deleting ATRS1 augmented both the constitutive and the heat-shock-induced luminescence, suggesting that this element represses transcription. Interestingly, replacing the element with random sequences of the same length and A+T content delivered the wild-type luminescence pattern, proving that the element's high A+T content is crucial for its effects. Deleting ATRS2 decreased luminescence dramatically and almost abolished heat-shock inducibility and so did replacing the element with random sequences matching the element's length and A+T content, suggesting that ATRS2's effects on transcription and heat-shock inducibility involve a common mechanism requiring at least in part the element's specific primary structure. Finally, constitutive and heat-shock luminescence were reduced strongly when two putative binding sites for the Zeste transcription factor identified within ATRS2 were altered through site-directed mutagenesis, and the heat-shock-induced luminescence increased when Zeste was over-expressed, indicating that Zeste participates in the effects mapped to ATRS2 at least in part. AT-rich sequences are common in promoters and our results suggest that they should play important

EFFECT OF EXPOSURE PROTOCOL AND HEAT SHOCK PROTEIN EXPRESSION ON ARSENITE INDUCED GENOTOXICITY IN MCF-7 BREAST CANCER CELLS

EPA Science Inventory

Effect of exposure protocol and heat shock protein expression on arsenite induced genotoxicity in MCF-7 breast cancer cells

The genotoxic effects of arsenic (As) are well accepted, yet its mechanism of action is not clearly defined. Heat-shock proteins (HSPs) protect...

Inhibition of apoptosis by p26: implications for small heat shock protein function during Artemia development.

PubMed

Villeneuve, Tania S; Ma, Xiaocui; Sun, Yu; Oulton, Mindy M; Oliver, Ann E; MacRae, Thomas H

2006-01-01

p26, an abundantly expressed small heat shock protein, is thought to establish stress resistance in oviparously developing embryos of the crustacean Artemia franciscana by preventing irreversible protein denaturation, but it might also promote survival by inhibiting apoptosis. To test this possibility, stably transfected mammalian cells producing p26 were generated and their ability to resist apoptosis induction determined. Examination of immunofluorescently stained transfected 293H cells by confocal microscopy demonstrated p26 is diffusely distributed in the cytoplasm with a minor amount of the protein in nuclei. As shown by immunoprobing of Western blots, p26 constituted approximately 0.6% of soluble cell protein. p26 localization and quantity were unchanged during prolonged culture, and the protein had no apparent ill effects on transfected cells. Molecular sieve chromatography in Sepharose 6B revealed p26 oligomers of about 20 monomers, with a second fraction occurring as larger aggregates. A similar pattern was observed in sucrose gradients, but overall oligomer size was smaller. Mammalian cells containing p26 were more thermotolerant than cells transfected with the expression vector only, and as measured by annexin V labeling, Hoescht 33342 nuclear staining and procaspase-3 activation, transfected cells effectively resisted apoptosis induction by heat and staurosporine. The ability to confer thermotolerance and limit heat-induced apoptosis is important because Artemia embryos are frequently exposed to high temperature in their natural habitat. p26 also blocked apoptosis in transfected cells during drying and rehydration, findings with direct relevance to Artemia life history characteristics because desiccation terminates cyst diapause. Thus, in addition to functioning as a molecular chaperone, p26 inhibits apoptosis, an activity shared by other small heat shock proteins and with the potential to play an important role during Artemia embryo development.

Deficiency of heat shock transcription factor 1 suppresses heat stress-associated increase in slow soleus muscle mass of mice.

PubMed

Ohno, Y; Egawa, T; Yokoyama, S; Nakai, A; Sugiura, T; Ohira, Y; Yoshioka, T; Goto, K

2015-12-01

Effects of heat shock transcription factor 1 (HSF1) deficiency on heat stress-associated increase in slow soleus muscle mass of mice were investigated. Both HSF1-null and wild-type mice were randomly assigned to control and heat-stressed groups. Mice in heat-stressed group were exposed to heat stress (41 °C for 60 min) in an incubator without anaesthesia. Significant increase in wet and dry weights, and protein content of soleus muscle in wild-type mice was observed seven days after the application of the heat stress. However, heat stress had no impact on soleus muscle mass in HSF1-null mice. Neither type of mice exhibited much effect of heat stress on HSF mRNA expression (HSF1, HSF2 and HSF4). On the other hand, heat stress upregulated heat shock proteins (HSPs) at the mRNA (HSP72) and protein (HSP72 and HSP110) levels in wild-type mice, but not in HSF1-null mice. The population of Pax7-positive nuclei relative to total myonuclei of soleus muscle in wild-type mice was significantly increased by heat stress, but not in HSF1-null mice. Furthermore, the absence of HSF1 gene suppressed heat stress-associated phosphorylation of Akt and p70 S6 kinase (p-p70S6K) in soleus muscle. Heat stress-associated increase in skeletal muscle mass may be induced by HSF1 and/or HSF1-mediated stress response that activates muscle satellite cells and Akt/p70S6K signalling pathway. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Magnetogasdynamic spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes

NASA Astrophysics Data System (ADS)

Nath, G.; Vishwakarma, J. P.

2016-11-01

Similarity solutions are obtained for the flow behind a spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes, in the presence of a spatially decreasing azimuthal magnetic field. The shock wave is driven by a piston moving with time according to power law. The radiation is considered to be of the diffusion type for an optically thick grey gas model and the heat conduction is expressed in terms of Fourier's law for heat conduction. Similarity solutions exist only when the surrounding medium is of constant density. The gas is assumed to have infinite electrical conductivity and to obey a simplified van der Waals equation of state. It is shown that an increase of the gravitational parameter or the Alfven-Mach number or the parameter of the non-idealness of the gas decreases the compressibility of the gas in the flow-field behind the shock, and hence there is a decrease in the shock strength. The pressure and density vanish at the inner surface (piston) and hence a vacuum is formed at the center of symmetry. The shock waves in conducting non-ideal gas under gravitational field with conductive and radiative heat fluxes can be important for description of shocks in supernova explosions, in the study of a flare produced shock in the solar wind, central part of star burst galaxies, nuclear explosion etc. The solutions obtained can be used to interpret measurements carried out by space craft in the solar wind and in neighborhood of the Earth's magnetosphere.

Absence of Sperm Factors as in the Parthenogenesis Does Not Interfere on Bovine Embryo Sensitiveness to Heat Shock at Pre-Implantation Stage.

PubMed

Camargo, L S A; Paludo, F; Pereira, M M; Wohlres-Viana, S; Gioso, M M; Carvalho, B C; Quintao, C C R; Viana, J H M

2016-02-01

Oocyte has been considered the major contributor for embryo thermo-tolerance. However, it was shown that sperm factors can be transferred to the oocyte during fertilization, raising the question of whether the absence of such factors could interfere on embryo thermo-tolerance. In this study, we used parthenogenesis to generate bovine embryos without spermatozoa in order to test whether the absence of sperm factors could influence their thermo-sensitiveness at early stages. In vitro fertilized (IVF) and parthenogenetic (PA) embryos at 44 h post-insemination/chemical activation were exposed to 38.5°C (control) or 41°C (heat shock) for 12 h and then developed for 48 h and up to blastocyst stage. Apoptosis index and expression of PRDX1, GLUT1, GLUT5 and IGF1r genes in blastocysts derived from heat-shocked embryos were also evaluated. The heat shock decreased the blastocyst rate at day seven (p < 0.05) for IVF embryos and at day eight (p < 0.01) for both IVF and PA embryos. Total cell number was not affected by heat shock in IVF and PA blastocysts, but there was an increased proportion (p < 0.05) of apoptotic cells in heat-shocked embryos when compared to controls. There was no interaction (p > 0.05) between method of activation (IVF and PA) and temperature (38.5°C or 41.5°C) for all developmental parameters evaluated. Expression of GLUT1 gene was downregulated (p < 0.05) by heat shock in both IVF and PA blastocyst whereas expression of GLUT5 and IGF1r genes was downregulated (p < 0.05) by heat shock in PA blastocysts. Those data show that the heat shock affects negatively the embryo development towards blastocysts stage, increases the apoptotic index and disturbed the expression of some genes in both IVF and PA embryos, indicating that the presence or absence of sperm factors does not influence the sensitivity of the bovine embryo to heat shock. © 2015 Blackwell Verlag GmbH.

Thermographic Phosphor Measurements of Shock-Shock Interactions on a Swept Cylinder

NASA Technical Reports Server (NTRS)

Jones, Michelle L.; Berry, Scott A.

2013-01-01

The effects of fin leading-edge radius and sweep angle on peak heating rates due to shock-shock interactions were investigated in the NASA Langley Research Center 20-inch Mach 6 Air Tunnel. The fin model leading edges, which represent cylindrical leading edges or struts on hypersonic vehicles, were varied from 0.25 inches to 0.75 inches in radius. A 9deg wedge generated a planar oblique shock at 16.7deg to the flow that intersected the fin bow shock, producing a shock-shock interaction that impinged on the fin leading edge. The fin angle of attack was varied from 0deg (normal to the free-stream) to 15deg and 25deg swept forward. Global temperature data was obtained from the surface of the fused silica fins using phosphor thermography. Metal oil flow models with the same geometries as the fused silica models were used to visualize the streamline patterns for each angle of attack. High-speed zoom-schlieren videos were recorded to show the features and temporal unsteadiness of the shock-shock interactions. The temperature data were analyzed using one-dimensional semi-infinite as well as one- and two-dimensional finite-volume methods to determine the proper heat transfer analysis approach to minimize errors from lateral heat conduction due to the presence of strong surface temperature gradients induced by the shock interactions. The general trends in the leading-edge heat transfer behavior were similar for the three shock-shock interactions, respectively, between the test articles with varying leading-edge radius. The dimensional peak heat transfer coefficient augmentation increased with decreasing leading-edge radius. The dimensional peak heat transfer output from the two-dimensional code was about 20% higher than the value from a standard, semi-infinite onedimensional method.

The rpoE operon regulates heat stress response in Burkholderia pseudomallei.

PubMed

Vanaporn, Muthita; Vattanaviboon, Paiboon; Thongboonkerd, Visith; Korbsrisate, Sunee

2008-07-01

Burkholderia pseudomallei is a gram-negative bacterium and the causative agent of melioidosis, one of the important lethal diseases in tropical regions. In this article, we demonstrate the crucial role of the B. pseudomallei rpoE locus in the response to heat stress. The rpoE operon knockout mutant exhibited growth retardation and reduced survival when exposed to a high temperature. Expression analysis using rpoH promoter-lacZ fusion revealed that heat stress induction of rpoH, which encodes heat shock sigma factor (sigma(H)), was abolished in the B. pseudomallei rpoE mutant. Analysis of the rpoH promoter region revealed sequences sharing high homology to the consensus sequence of sigma(E)-dependent promoters. Moreover, the putative heat-induced sigma(H)-regulated heat shock proteins (i.e. GroEL and HtpG) were also absent in the rpoE operon mutant. Altogether, our data suggest that the rpoE operon regulates B. pseudomallei heat stress response through the function of rpoH.

A Novel mouse model of enhanced proteostasis: Full-length human heat shock factor 1 transgenic mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, Anson, E-mail: piercea2@uthscsa.edu; Barshop Institute for Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, 78229; The Department of Veteran's Affairs, South Texas Veterans Health Care System, San Antonio, Texas, 78284

2010-11-05

Research highlights: {yields} Development of mouse overexpressing native human HSF1 in all tissues including CNS. {yields} HSF1 overexpression enhances heat shock response at whole-animal and cellular level. {yields} HSF1 overexpression protects from polyglutamine toxicity and favors aggresomes. {yields} HSF1 overexpression enhances proteostasis at the whole-animal and cellular level. -- Abstract: The heat shock response (HSR) is controlled by the master transcriptional regulator heat shock factor 1 (HSF1). HSF1 maintains proteostasis and resistance to stress through production of heat shock proteins (HSPs). No transgenic model exists that overexpresses HSF1 in tissues of the central nervous system (CNS). We generated a transgenicmore » mouse overexpressing full-length non-mutant HSF1 and observed a 2-4-fold increase in HSF1 mRNA and protein expression in all tissues studied of HSF1 transgenic (HSF1{sup +/0}) mice compared to wild type (WT) littermates, including several regions of the CNS. Basal expression of HSP70 and 90 showed only mild tissue-specific changes; however, in response to forced exercise, the skeletal muscle HSR was more elevated in HSF1{sup +/0} mice compared to WT littermates and in fibroblasts following heat shock, as indicated by levels of inducible HSP70 mRNA and protein. HSF1{sup +/0} cells elicited a significantly more robust HSR in response to expression of the 82 repeat polyglutamine-YFP fusion construct (Q82YFP) and maintained proteasome-dependent processing of Q82YFP compared to WT fibroblasts. Overexpression of HSF1 was associated with fewer, but larger Q82YFP aggregates resembling aggresomes in HSF1{sup +/0} cells, and increased viability. Therefore, our data demonstrate that tissues and cells from mice overexpressing full-length non-mutant HSF1 exhibit enhanced proteostasis.« less

Small Heat Shock Proteins Can Release Light Dependence of Tobacco Seed during Germination1[OPEN

PubMed Central

Koo, Hyun Jo; Park, Soo Min; Kim, Keun Pill; Suh, Mi Chung; Lee, Mi Ok; Lee, Seong-Kon; Xinli, Xia

2015-01-01

Small heat shock proteins (sHSPs) function as ATP-independent molecular chaperones, and although the production and function of sHSPs have often been described under heat stress, the expression and function of sHSPs in fundamental developmental processes, such as pollen and seed development, have also been confirmed. Seed germination involves the breaking of dormancy and the resumption of embryo growth that accompany global changes in transcription, translation, and metabolism. In many plants, germination is triggered simply by imbibition of water; however, different seeds require different conditions in addition to water. For small-seeded plants, like Arabidopsis (Arabidopsis thaliana), lettuce (Lactuca sativa), tomato (Solanum lycopersicum), and tobacco (Nicotiana tabacum), light is an important regulator of seed germination. The facts that sHSPs accumulate during seed development, sHSPs interact with various client proteins, and seed germination accompanies synthesis and/or activation of diverse proteins led us to investigate the role of sHSPs in seed germination, especially in the context of light dependence. In this study, we have built transgenic tobacco plants that ectopically express sHSP, and the effect was germination of the seeds in the dark. Administering heat shock to the seeds also resulted in the alleviation of light dependence during seed germination. Subcellular localization of ectopically expressed sHSP was mainly observed in the cytoplasm, whereas heat shock-induced sHSPs were transported to the nucleus. We hypothesize that ectopically expressed sHSPs in the cytoplasm led the status of cytoplasmic proteins involved in seed germination to function during germination without additional stimulus and that heat shock can be another signal that induces seed germination. PMID:25604531

Heat stress and cardiovascular, hormonal, and heat shock proteins in humans.

PubMed

Iguchi, Masaki; Littmann, Andrew E; Chang, Shuo-Hsiu; Wester, Lydia A; Knipper, Jane S; Shields, Richard K

2012-01-01

Conditions such as osteoarthritis, obesity, and spinal cord injury limit the ability of patients to exercise, preventing them from experiencing many well-documented physiologic stressors. Recent evidence indicates that some of these stressors might derive from exercise-induced body temperature increases. To determine whether whole-body heat stress without exercise triggers cardiovascular, hormonal, and extracellular protein responses of exercise. Randomized controlled trial. University research laboratory. Twenty-five young, healthy adults (13 men, 12 women; age = 22.1 ± 2.4 years, height = 175.2 ± 11.6 cm, mass = 69.4 ± 14.8 kg, body mass index = 22.6 ± 4.0) volunteered. Participants sat in a heat stress chamber with heat (73°C) and without heat (26°C) stress for 30 minutes on separate days. We obtained blood samples from a subset of 13 participants (7 men, 6 women) before and after exposure to heat stress. Extracellular heat shock protein (HSP72) and catecholamine plasma concentration, heart rate, blood pressure, and heat perception. After 30 minutes of heat stress, body temperature measured via rectal sensor increased by 0.8°C. Heart rate increased linearly to 131.4 ± 22.4 beats per minute (F₆,₂₄ = 186, P < .001) and systolic and diastolic blood pressure decreased by 16 mm Hg (F₆,₂₄ = 10.1, P < .001) and 5 mm Hg (F₆,₂₄ = 5.4, P < .001), respectively. Norepinephrine (F₁,₁₂ = 12.1, P = .004) and prolactin (F₁,₁₂ = 30.2, P < .001) increased in the plasma (58% and 285%, respectively) (P < .05). The HSP72 (F₁,₁₂ = 44.7, P < .001) level increased with heat stress by 48.7% ± 53.9%. No cardiovascular or blood variables showed changes during the control trials (quiet sitting in the heat chamber with no heat stress), resulting in differences between heat and control trials. We found that whole-body heat stress triggers some of the physiologic responses observed with exercise. Future studies are necessary to investigate whether

Reactive oxygen species promote heat shock protein 90-mediated HBV capsid assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Yoon Sik, E-mail: yumshak@naver.com; Seo, Hyun Wook, E-mail: suruk@naver.com; Jung, Guhung, E-mail: drjung@snu.ac.kr

2015-02-13

Hepatitis B virus (HBV) infection induces reactive oxygen species (ROS) production and has been associated with the development of hepatocellular carcinoma (HCC). ROS are also an important factor in HCC because the accumulated ROS leads to abnormal cell proliferation and chromosome mutation. In oxidative stress, heat shock protein 90 (Hsp90) and glutathione (GSH) function as part of the defense mechanism. Hsp90 prevents cellular component from oxidative stress, and GSH acts as antioxidants scavenging ROS in the cell. However, it is not known whether molecules regulated by oxidative stress are involved in HBV capsid assembly. Based on the previous study thatmore » Hsp90 facilitates HBV capsid assembly, which is an important step for the packing of viral particles, here, we show that ROS enrich Hsp90-driven HBV capsid formation. In cell-free system, HBV capsid assembly was facilitated by ROS with Hsp90, whereas it was decreased without Hsp90. In addition, GSH inhibited the function of Hsp90 to decrease HBV capsid assembly. Consistent with the result of cell-free system, ROS and buthionine sulfoximine (BS), an inhibitor of GSH synthesis, increased HBV capsid formation in HepG2.2.15 cells. Thus, our study uncovers the interplay between ROS and Hsp90 during HBV capsid assembly. - Highlights: • We examined H{sub 2}O{sub 2} and GSH modulate HBV capsid assembly. • H{sub 2}O{sub 2} facilitates HBV capsid assembly in the presence of Hsp90. • GSH inhibits function of Hsp90 in facilitating HBV capsid assembly. • H{sub 2}O{sub 2} and GSH induce conformation change of Hsp90.« less

Numerical simulation of heat fluxes in a two-temperature plasma at shock tube walls

NASA Astrophysics Data System (ADS)

Kuznetsov, E. A.; Poniaev, S. A.

2015-12-01

Numerical simulation of a two-temperature three-component Xenon plasma flow is presented. A solver based on the OpenFOAM CFD software package is developed. The heat flux at the shock tube end wall is calculated and compared with experimental data. It is shown that the heat flux due to electrons can be as high as 14% of the total heat flux.

Heat shock factor-1 knockout induces multidrug resistance gene, MDR1b, and enhances P-glycoprotein (ABCB1)-based drug extrusion in the heart

PubMed Central

Krishnamurthy, Karthikeyan; Vedam, Kaushik; Kanagasabai, Ragu; Druhan, Lawrence J.; Ilangovan, Govindasamy

2012-01-01

Heat-shock factor 1 (HSF-1), a transcription factor for heat-shock proteins (HSPs), is known to interfere with the transcriptional activity of many oncogenic factors. In the present work, we have discovered that HSF-1 ablation induced the multidrug resistance gene, MDR1b, in the heart and increased the expression of P-glycoprotein (P-gp, ABCB1), an ATP binding cassette that is usually associated with multidrug-resistant cancer cells. The increase in P-gp enhanced the extrusion of doxorubicin (Dox) to alleviate Dox-induced heart failure and reduce mortality in mice. Dox-induced left ventricular (LV) dysfunction was significantly reduced in HSF-1−/− mice. DNA-binding activity of NF-κB was higher in HSF-1−/− mice. IκB, the NF-κB inhibitor, was depleted due to enhanced IκB kinase (IKK)-α activity. In parallel, MDR1b gene expression and a large increase in P-gp and lowering Dox loading were observed in HSF-1−/− mouse hearts. Moreover, application of the P-gp antagonist, verapamil, increased Dox loading in HSF-1−/− cardiomyocytes, deteriorated cardiac function in HSF-1−/− mice, and decreased survival. MDR1 promoter activity was higher in HSF-1−/− cardiomyocytes, whereas a mutant MDR1 promoter with heat-shock element (HSE) mutation showed increased activity only in HSF-1+/+ cardiomyocytes. However, deletion of HSE and NF-κB binding sites diminished luminescence in both HSF-1+/+ and HSF-1−/− cardiomyocytes, suggesting that HSF-1 inhibits MDR1 activity in the heart. Thus, because high levels of HSF-1 are attributed to poor prognosis of cancer, systemic down-regulation of HSF-1 before chemotherapy is a potential therapeutic approach to ameliorate the chemotherapy-induced cardiotoxicity and enhance cancer prognosis. PMID:22615365

Glutamine reduces myocardial cell apoptosis in a rat model of sepsis by promoting expression of heat shock protein 90.

PubMed

Li, Wanxia; Tao, Shaoyu; Wu, Qinghua; Wu, Tao; Tao, Ran; Fan, Jun

2017-12-01

Myocardial cell injury and cardiac myocyte apoptosis are associated with sepsis. Glutamine (Gln) has been reported to repair myocardial cell injury. The aim of this study was to explore the role of Gln on cardiac myocytes in a cecal ligation and puncture (CLP) model of sepsis in Wistar rats. Following induction of sepsis in a CLP rat model, viral encoding heat shock protein 90 (Hsp90) gene and Hsp90dsDNA were designed to express and knockdown Hsp90, respectively. Rat cardiac tissues were examined histologically, and apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling staining. The expression of B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein, Hsp90, p53 upregulated modulator of apoptosis, and p53 was measured by western blotting and real-time polymerase chain reaction. Caspase-3, caspase-8, and caspase-9 were detected by enzyme-linked immunosorbent assay. Rat cardiac myocyte damage induced by CLP was reduced by Gln treatment and Hsp90 overexpression, and these changes were reversed by Hsp90 knockdown. Bcl-2 expression, Bcl-2-associated X protein, p53, p53 upregulated modulator of apoptosis, caspase-8, caspase-9, and caspase-3 activities were significantly upregulated in the CLP model, which were reduced by Gln treatment and Hsp90 overexpression. Gln reduced apoptosis of cardiac myocytes in a rat model of sepsis, by promoting Hsp90 expression. Further studies are needed to determine the possible therapeutic action of Gln in sepsis in human tissue. Copyright © 2017 Elsevier Inc. All rights reserved.

Pregermination heat shock and seedling growth of fire-following Fabaceae from four Mediterranean-climate regions

NASA Astrophysics Data System (ADS)

Hanley, Mick E.; Fenner, Michael; Ne'eman, Gidi

2001-12-01

The role of heat-shock in stimulating the germination of soil-stored seeds from fire-following plant species is well known. However, the effects of high pre-germination temperatures on subsequent seedling growth are less well understood. In this study, we examined the effect of pre-germination heat shock at five temperatures (60°, 75°, 90°, 105° and 120°C, each applied for 5 min) on the seedling growth of four, fire-following Fabaceae species from four Mediterranean-type ecosystems; Hippocrepis multisiliquosa (Israel), Gastrolobium villosum (Western Australia), Cyclopia pubescens (South Africa) and Lupinus succulentus (California). Following heat treatment and subsequent germination, seedlings were grown in controlled conditions before being harvested at either 10, 20- or 40 d old. A significant increase in mean dry weight biomass was found at 10 days for Hippocrepis seedlings germinated from seeds pre-heated to 90°C. However, subsequent comparison of mean dry weight biomass for seedlings of this species at 20 and 40 d old showed no significant response to heat shock pre-treatment. Similarly, an initial increase in growth of Gastrolobium seedlings germinated from seeds heated to 90° and 105°C disappeared as the plants matured. Seedling growth of Lupinus and Cyclopia was unaffected by the pre-germination heat treatment of their seeds. Since seedling competition is influenced by the size and growth rates of neighbouring plants, any changes in seedling growth rates as a consequence of the temperature environment experienced by their seeds, may therefore influence patterns of post-fire plant community recovery.

Low heat-shock thresholds in wild Antarctic inter-tidal limpets (Nacella concinna).

PubMed

Clark, Melody S; Geissler, Paul; Waller, Catherine; Fraser, Keiron P P; Barnes, David K A; Peck, Lloyd S

2008-01-01

Heat shock proteins (HSPs) are a family of genes classically used to measure levels of organism stress. We have previously identified two HSP70 genes (HSP70A and HSP70B) in sub-tidal populations of the Antarctic limpet (Nacella concinna). These genes are up-regulated in response to increased seawater temperatures of 15 degrees C or more during acute heat shock experiments, temperatures that have very little basis when considering the current Antarctic ecology of these animals. Therefore, the question was posed as to whether these animals could express HSP70 genes when subjected to more complex environmental conditions, such as those that occur in the inter-tidal. Inter-tidal limpets were collected on three occasions in different weather conditions at South Cove, Rothera Point, over a complete tidal cycle, and the expression levels of the HSP70 genes were measured. Both genes showed relative up-regulation of gene expression over the period of the tidal cycle. The average foot temperature of these animals was 3.3 degrees C, far below that of the acute heat shock experiments. These experiments demonstrate that the temperature and expression levels of HSP production in wild animals cannot be accurately extrapolated from experimentally induced treatments, especially when considering the complexity of stressors in the natural environment. However, experimental manipulation can provide molecular markers for identifying stress in Antarctic molluscs, provided it is accompanied by environmental validation, as demonstrated here.

Casein Kinase II Induced Polymerization of Soluble TDP-43 into Filaments Is Inhibited by Heat Shock Proteins

PubMed Central

Davis, Mary; Lin, Wen-Lang; Cook, Casey; Dunmore, Judy; Tay, William; Menkosky, Kyle; Cao, Xiangkun; Petrucelli, Leonard; DeTure, Michael

2014-01-01

Background Trans-activation Response DNA-binding Protein-43 (TDP-43) lesions are observed in Amyotrophic Lateral Sclerosis (ALS), Frontotemporal Lobar Degeneration with ubiquitin inclusions (FTLD-TDP) and 25–50% of Alzheimer's Disease (AD) cases. These abnormal protein inclusions are composed of either amorphous TDP-43 aggregates or highly ordered filaments. The filamentous TDP-43 accumulations typically contain clean 10–12 nm filaments though wider 18–20 nm coated filaments may be observed. The TDP-43 present within these lesions is phosphorylated, truncated and ubiquitinated, and these modifications appear to be abnormal as they are linked to both a cellular heat shock response and microglial activation. The mechanisms associated with this abnormal TDP-43 accumulation are believed to result in a loss of TDP-43 function, perhaps due to the post-translational modifications or resulting from physical sequestration of the TDP-43. The formation of TDP-43 inclusions involves cellular translocation and conversion of TDP-43 into fibrillogenic forms, but the ability of these accumulations to sequester normal TDP-43 and propagate this behavior between neurons pathologically is mostly inferred. The lack of methodology to produce soluble full length TDP-43 and recapitulate this polymerization into filaments as observed in disease has limited our understanding of these pathogenic cascades. Results The protocols described here generate soluble, full-length and untagged TDP-43 allowing for a direct assessment of the impact of various posttranslational modifications on TDP-43 function. We demonstrate that Casein Kinase II (CKII) promotes the polymerization of this soluble TDP-43 into 10 nm diameter filaments that resemble the most common TDP-43 structures observed in disease. Furthermore, these filaments are recognized as abnormal by Heat Shock Proteins (HSPs) which can inhibit TDP-43 polymerization or directly promote TDP-43 filament depolymerization. Conclusion These

Cellular stress induces cancer stem-like cells through expression of DNAJB8 by activation of heat shock factor 1.

PubMed

Kusumoto, Hiroki; Hirohashi, Yoshihiko; Nishizawa, Satoshi; Yamashita, Masamichi; Yasuda, Kazuyo; Murai, Aiko; Takaya, Akari; Mori, Takashi; Kubo, Terufumi; Nakatsugawa, Munehide; Kanaseki, Takayuki; Tsukahara, Tomohide; Kondo, Toru; Sato, Noriyuki; Hara, Isao; Torigoe, Toshihiko

2018-03-01

In a previous study, we found that DNAJB8, a heat shock protein (HSP) 40 family member is expressed in kidney cancer stem-like cells (CSC)/cancer-initiating cells (CIC) and that it has a role in the maintenance of kidney CSC/CIC. Heat shock factor (HSF) 1 is a key transcription factor for responses to stress including heat shock, and it induces HSP family expression through activation by phosphorylation. In the present study, we therefore examined whether heat shock (HS) induces CSC/CIC. We treated the human kidney cancer cell line ACHN with HS, and found that HS increased side population (SP) cells. Western blot analysis and qRT-PCR showed that HS increased the expression of DNAJB8 and SOX2. Gene knockdown experiments using siRNAs showed that the increase in SOX2 expression and SP cell ratio depends on DNAJB8 and that the increase in DNAJB8 and SOX2 depend on HSF1. Furthermore, treatment with a mammalian target of rapamycin (mTOR) inhibitor, temsirolimus, decreased the expression of DNAJB8 and SOX2 and the ratio of SP cells. Taken together, the results indicate that heat shock induces DNAJB8 by activation of HSF1 and induces cancer stem-like cells. © 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Heat shock instructs hESCs to exit from the self-renewal program through negative regulation of OCT4 by SAPK/JNK and HSF1 pathway.

PubMed

Byun, Kyunghee; Kim, Taek-Kyun; Oh, Jeehyun; Bayarsaikhan, Enkhjargal; Kim, Daesik; Lee, Min Young; Pack, Chan-Gi; Hwang, Daehee; Lee, Bonghee

2013-11-01

Environmental factors affect self-renewal of stem cells by modulating the components of self-renewal networks. Heat shock, an environmental factor, induces heat shock factors (HSFs), which up-regulate stress response-related genes. However, the link of heat shock to self-renewal of stem cells has not been elucidated yet. Here, we present the direct link of heat shock to a core stem cell regulator, OCT4, in the self-renewal network through SAPK/JNK and HSF1 pathway. We first showed that heat shock initiated differentiation of human embryonic stem cells (hESCs). Gene expression analysis revealed that heat shock increased the expression of many genes involved in cellular processes related to differentiation of stem cells. We then examined the effects of HSFs induced by heat shock on core self-renewal factors. Among HSFs, heat shock induced mainly HSF1 in hESCs. The HSF1 repressed the expression of OCT4, leading to the differentiation of hESCs and the above differentiation-related gene expression change. We further examined the effects of the upstream MAP (mitogen-activated protein) kinases of HSF1 on the repression of OCT4 expression by HSF1. Among the MAP kinases, SAPK/JNK controlled predominantly the repression of the OCT4 expression by HSF1. The direct link of heat shock to the core self-renewal regulator through SAPK/JNK and HSF1 provides a fundamental basis for understanding the effect of heat and other stresses involving activation of HSF1 on the self-renewal program and further controlling differentiation of hESCs in a broad spectrum of stem cell applications using these stresses. © 2013.

Molecular characterization and expression analysis of a heat shock protein 90 gene from disk abalone (Haliotis discus).

PubMed

Wang, Ning; Whang, Ilson; Lee, Jae-Seong; Lee, Jehee

2011-06-01

Heat shock protein 90s (hsp90s) are chaperones that contribute to the proper folding of cellular proteins and help animals cope with the cellular protein damages in stress conditions. In this study, an hsp90 gene was isolated from disc abalone (Haliotis discus). The complete nucleotide sequence of the hsp90 gene contains an open reading frame of 2,184 base pairs, encoding an 84 kDa protein. Disk abalone hsp90 shares high sequence similarity with other hsp90 family proteins. Although the phylogenetic analysis did not classify it into the hsp90α group, the inductivity of this gene was confirmed by heat shock and lipopolysaccharide (LPS) challenge test. Disk abalone hsp90 gene displayed a rapid and reversible induction response to both an exposure of typical heat shock and the LPS challenge. Once given the sublethal heat shock treatment, the transcription of disk abalone hsp90 gene was significantly up-regulated. With a recovery of 12 h, the transcription of disk abalone hsp90 gene gradually attenuated to the control level. These observations reflected the feedback regulation of abalone heat shock responses faithfully. In response to LPS challenge, the transcription of disk abalone hsp90 gene was significantly increased within 2 h and it approached maximum induction at 4 h later and recovered finally the reference level in 24 h. Take all together, the cloning and expression analysis of disk abalone hsp90 gene provided useful molecular information of abalone responses in stress conditions and potential ways to monitor the chronic stressors in abalone culture environments and diagnose the animal health status.

Heat-shock properties in yttrium-oxide films synthesized from metal-ethylenediamine tetraacetic acid complex through flame-spray apparatus

NASA Astrophysics Data System (ADS)

Xin, D. Y.; Komatsu, Keiji; Abe, Keita; Costa, Takashi; Ikeda, Yutaka; Nakamura, Atsushi; Ohshio, Shigeo; Saitoh, Hidetoshi

2017-03-01

Recently, a new deposition technique using a metal-ethylenediamine tetraacetic acid (EDTA) complex has been developed. In this study, the heat-shock properties of metal-oxide films synthesized from a metal-EDTA complex were investigated. Y2O3 films were synthesized on stainless-steel (SUS) substrate from EDTA•Y•H through the combustion of H2-O2 gas. A cyclic heat-shock test was conducted on the fabricated Y2O3 films through exposure to the H2-O2 flame. The existence of Y2O3 crystals was confirmed. Surface cracks or damages were not observed in the samples after the cyclic thermal test. Although the number of cross-sectional cracks, crack lengths, and cracks per unit area was increased by the heat shock, delaminations were not observed in the Y2O3 films. The results show that the prepared Y2O3 films have high thermal-shock resistance and are suitable for use as thermal barrier coatings.

Insulated hsp70B' promoter: stringent heat-inducible activity in replication-deficient, but not replication-competent adenoviruses.

PubMed

Rohmer, Stanimira; Mainka, Astrid; Knippertz, Ilka; Hesse, Andrea; Nettelbeck, Dirk M

2008-04-01

Key to the realization of gene therapy is the development of efficient and targeted gene transfer vectors. Therapeutic gene transfer by replication-deficient or more recently by conditionally replication-competent/oncolytic adenoviruses has shown much promise. For specific applications, however, it will be advantageous to provide vectors that allow for external control of gene expression. The efficient cellular heat shock system in combination with available technology for focused and controlled hyperthermia suggests heat-regulated transcription control as a promising tool for this purpose. We investigated the feasibility of a short fragment of the human hsp70B' promoter, with and without upstream insulator elements, for the regulation of transgene expression by replication-deficient or oncolytic adenoviruses. Two novel adenoviral vectors with an insulated hsp70B' promoter were developed and showed stringent heat-inducible gene expression with induction ratios up to 8000-fold. In contrast, regulation of gene expression from the hsp70B' promoter without insulation was suboptimal. In replication-competent/oncolytic adenoviruses regulation of the hsp70B' promoter was lost specifically during late replication in permissive cells and could not be restored by the insulators. We developed novel adenovirus gene transfer vectors that feature improved and stringent regulation of transgene expression from the hsp70B' promoter using promoter insulation. These vectors have potential for gene therapy applications that benefit from external modulation of therapeutic gene expression or for combination therapy with hyperthermia. Furthermore, our study reveals that vector replication can deregulate inserted cellular promoters, an observation which is of relevance for the development of replication-competent/oncolytic gene transfer vectors. (c) 2008 John Wiley & Sons, Ltd.

Heat Tolerance Induction of the Indian Meal Moth (Lepidoptera: Pyralidae) Is Accompanied by Upregulation of Heat Shock Proteins and Polyols.

PubMed

Kim, Minhyun; Lee, Seunghee; Chun, Yong Shik; Na, Jahyun; Kwon, Hyeok; Kim, Wook; Kim, Yonggyun

2017-08-01

The Indian meal moth, Plodia interpunctella, causes massive damage to stored grains and processed foods. Heat treatment has been widely used to control insect pests infesting stored grains. However, heat treatment may result in unsatisfactory control owing to heat tolerance of target insects. This study quantified the heat tolerance and analyzed its induction in P. interpunctella. Susceptibility of P. interpunctella to different high temperatures was assessed in all developmental stages. Heat treatment at 44 °C for 1 h caused significant mortalities to all developmental stages, with late-instar larvae exhibiting the highest tolerance. However, the survivorship to heat treatment was significantly increased by pre-exposure to 37 °C for 30 min. The induction of heat tolerance was accompanied by upregulation of two heat shock proteins of Hsc70 and Hsp90. Trehalose and glycerol concentrations in the hemolymph also increased after pre-exposure to 37 °C for 30 min. RNA interference (RNAi) by specific double-stranded RNAs effectively suppressed the inducible expressions of both Hsc70 and Hsp90 in response to 37 °C for 30 min. Either RNAi of Hsc70 or Hsp90 significantly impaired the heat tolerance induction of P. interpunctella. These results suggest that the induction of heat tolerance in P. interpunctella involves the upregulation of these heat shock proteins and hemolymph polyol levels. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The 86-kilodalton antigen from Schistosoma mansoni is a heat-shock protein homologous to yeast HSP-90.

PubMed

Johnson, K S; Wells, K; Bock, J V; Nene, V; Taylor, D W; Cordingley, J S

1989-08-01

We report the sequence of a cDNA clone encoding an 86-kDa polypeptide antigen (p86) from Schistosoma mansoni. Fusion proteins made in Escherichia coli are recognized by human infection sera. The reading frame of this antigen is highly homologous to those of the large heat-shock proteins of Saccharomyces cerevisiae (HSP90) and Drosophila melanogaster (HSP83). mRNA encoding p86 increases in response to heat shock of adult worms, as does HSP70. Comparisons of the sequences of HSP70 and HSP83 homologues show that these two families of heat-shock proteins are not significantly related except for the last four amino acid residues, which are Glu-Glu-Val-Asp in every case. This sequence is not found at the carboxy terminus of any other protein in the current databases.

Developmentally regulated expression of APG-1, a member of heat shock protein 110 family in murine male germ cells.

PubMed

Kaneko, Y; Kimura, T; Nishiyama, H; Noda, Y; Fujita, J

1997-04-07

Apg-1 encodes a heat shock protein belonging to the heat shock protein 110 family, and is inducible by a 32 degrees C to 39 degrees C heat shock. Northern blot analysis of the testis from immature and adult mice, and of the purified germ cells revealed the quantitative change of the apg-1 transcripts during germ cell development. By in situ hybridization histochemistry the expressions of the apg-1 transcripts were detected in germ cells at specific stages of development including spermatocytes and spermatids. Although heat-induction of the apg-1 transcripts was observed in W/Wv mutant testis lacking germ cells, it was not detected in wild-type testis nor in the purified germ cells. Thus, the apg-1 expression is not heat-regulated but developmentally regulated in germ cells, suggesting that APG-1 plays a role in normal development of germ cells.

Structure and function of small heat shock/alpha-crystallin proteins: established concepts and emerging ideas.

PubMed

MacRae, T H

2000-06-01

Small heat shock/alpha-crystallin proteins are defined by conserved sequence of approximately 90 amino acid residues, termed the alpha-crystallin domain, which is bounded by variable amino- and carboxy-terminal extensions. These proteins form oligomers, most of uncertain quaternary structure, and oligomerization is prerequisite to their function as molecular chaperones. Sequence modelling and physical analyses show that the secondary structure of small heat shock/alpha-crystallin proteins is predominately beta-pleated sheet. Crystallography, site-directed spin-labelling and yeast two-hybrid selection demonstrate regions of secondary structure within the alpha-crystallin domain that interact during oligomer assembly, a process also dependent on the amino terminus. Oligomers are dynamic, exhibiting subunit exchange and organizational plasticity, perhaps leading to functional diversity. Exposure of hydrophobic residues by structural modification facilitates chaperoning where denaturing proteins in the molten globule state associate with oligomers. The flexible carboxy-terminal extension contributes to chaperone activity by enhancing the solubility of small heat shock/alpha-crystallin proteins. Site-directed mutagenesis has yielded proteins where the effect of the change on structure and function depends upon the residue modified, the organism under study and the analytical techniques used. Most revealing, substitution of a conserved arginine residue within the alpha-crystallin domain has a major impact on quaternary structure and chaperone action probably through realignment of beta-sheets. These mutations are linked to inherited diseases. Oligomer size is regulated by a stress-responsive cascade including MAPKAP kinase 2/3 and p38. Phosphorylation of small heat shock/alpha-crystallin proteins has important consequences within stressed cells, especially for microfilaments.

Glucose Starvation Alters Heat Shock Response, Leading to Death of Wild Type Cells and Survival of MAP Kinase Signaling Mutant

PubMed Central

Higgins, LeeAnn; Markowski, Todd; Brambl, Robert

2016-01-01

A moderate heat shock induces Neurospora crassa to synthesize large quantities of heat shock proteins that are protective against higher, otherwise lethal temperatures. However, wild type cells do not survive when carbohydrate deprivation is added to heat shock. In contrast, a mutant strain defective in a stress-activated protein kinase does survive the combined stresses. In order to understand the basis for this difference in survival, we have determined the relative levels of detected proteins in the mutant and wild type strain during dual stress, and we have identified gene transcripts in both strains whose quantities change in response to heat shock or dual stress. These data and supportive experimental evidence point to reasons for survival of the mutant strain. By using alternative respiratory mechanisms, these cells experience less of the oxidative stress that proves damaging to wild type cells. Of central importance, mutant cells recycle limited resources during dual stress by undergoing autophagy, a process that we find utilized by both wild type and mutant cells during heat shock. Evidence points to inappropriate activation of TORC1, the central metabolic regulator, in wild type cells during dual stress, based upon behavior of an additional signaling mutant and inhibitor studies. PMID:27870869

Elucidation of the molecular mechanism of heat shock proteins and its correlation with K722Q mutations in Lon protease.

PubMed

Bhattacharjee, Sanchari; Dasgupta, Rakhi; Bagchi, Angshuman

2017-09-01

Cells withstand the effects of temperature change with the help of small heat shock proteins IbpA and IbpB. The IbpAB protein complex interacts with Lon protease in their free form and gets degraded at physiological temperature when there is no temperature stress. However, the proteolytic degradation of IbpAB is diminished when Lon is mutated. The mutation K722Q in Lon brings about some structural changes so that the proteolytic interactions between the heat shock proteins with that of the mutated Lon protease are lost. However, the detailed molecular aspects of the interactions are not yet fully understood. In the present, we made an attempt to analyze the biochemical aspects of the interactions between the small heat shock proteins IbpAB with wild type and mutant Lon protease. We for the first time deciphered the molecular details of the mechanism of interaction of small heat shock proteins with Lon protease bearing K722Q mutation i.e. the interaction pattern of heat shock proteins with mutant Lon protease at physiological temperature in absence of proteolytic machinery. Our study may therefore be useful to elucidate the mechanistic details of the correlation with IbpA, IbpB and Lon protease. Copyright © 2017 Elsevier B.V. All rights reserved.

Larvae of related Diptera species from thermally contrasting habitats exhibit continuous up-regulation of heat shock proteins and high thermotolerance.

PubMed

Garbuz, David G; Zatsepina, Olga G; Przhiboro, Andrey A; Yushenova, Irina; Guzhova, Irina V; Evgen'ev, Michael B

2008-11-01

A population of Stratiomys japonica, a species belonging to the family Stratiomyidae (Diptera), common name 'soldier flies', occurs in a hot volcanic spring, which is apparently among the most inhospitable environments for animals because of chemical and thermal conditions. Larvae of this species, which naturally often experience temperatures more than 40 degrees C, have constitutively high concentrations of the normally inducible heat-shock protein Hsp70, but very low level of corresponding mRNA. Larvae of three other species of the same family, Stratiomys singularior, Nemotelus bipunctatus and Oxycera pardalina, are confined to different type semi-aquatic habitats with contrasting thermal regime. However, all of them shared the same pattern of Hsp70 expression. Interestingly, heat-shock treatment of S. japonica larvae activates heat-shock factor and significantly induces Hsp70 synthesis, whereas larvae of O. pardalina, a species from constant cold environment, produce significantly less Hsp70 in response to heat shock. Adults of the four species also exhibit lower, but detectable levels of Hsp70 without heat shock. Larvae of all species studied have very high tolerance to temperature stress in comparison with other Diptera species investigated, probably representing an inherent adaptive feature of all Stratiomyidae enabling successful colonization of highly variable and extreme habitats.

Translational control plays an important role in the adaptive heat-shock response of Streptomyces coelicolor

PubMed Central

Pothi, Radhika; Hesketh, Andrew; Möller-Levet, Carla; Hodgson, David A; Laing, Emma E; Stewart, Graham R; Smith, Colin P

2018-01-01

Abstract Stress-induced adaptations require multiple levels of regulation in all organisms to repair cellular damage. In the present study we evaluated the genome-wide transcriptional and translational changes following heat stress exposure in the soil-dwelling model actinomycete bacterium, Streptomyces coelicolor. The combined analysis revealed an unprecedented level of translational control of gene expression, deduced through polysome profiling, in addition to transcriptional changes. Our data show little correlation between the transcriptome and ‘translatome’; while an obvious downward trend in genome wide transcription was observed, polysome associated transcripts following heat-shock showed an opposite upward trend. A handful of key protein players, including the major molecular chaperones and proteases were highly induced at both the transcriptional and translational level following heat-shock, a phenomenon known as ‘potentiation’. Many other transcripts encoding cold-shock proteins, ABC-transporter systems, multiple transcription factors were more highly polysome-associated following heat stress; interestingly, these protein families were not induced at the transcriptional level and therefore were not previously identified as part of the stress response. Thus, stress coping mechanisms at the level of gene expression in this bacterium go well beyond the induction of a relatively small number of molecular chaperones and proteases in order to ensure cellular survival at non-physiological temperatures. PMID:29746664

Translational control plays an important role in the adaptive heat-shock response of Streptomyces coelicolor.

PubMed

Bucca, Giselda; Pothi, Radhika; Hesketh, Andrew; Möller-Levet, Carla; Hodgson, David A; Laing, Emma E; Stewart, Graham R; Smith, Colin P

2018-05-09

Stress-induced adaptations require multiple levels of regulation in all organisms to repair cellular damage. In the present study we evaluated the genome-wide transcriptional and translational changes following heat stress exposure in the soil-dwelling model actinomycete bacterium, Streptomyces coelicolor. The combined analysis revealed an unprecedented level of translational control of gene expression, deduced through polysome profiling, in addition to transcriptional changes. Our data show little correlation between the transcriptome and 'translatome'; while an obvious downward trend in genome wide transcription was observed, polysome associated transcripts following heat-shock showed an opposite upward trend. A handful of key protein players, including the major molecular chaperones and proteases were highly induced at both the transcriptional and translational level following heat-shock, a phenomenon known as 'potentiation'. Many other transcripts encoding cold-shock proteins, ABC-transporter systems, multiple transcription factors were more highly polysome-associated following heat stress; interestingly, these protein families were not induced at the transcriptional level and therefore were not previously identified as part of the stress response. Thus, stress coping mechanisms at the level of gene expression in this bacterium go well beyond the induction of a relatively small number of molecular chaperones and proteases in order to ensure cellular survival at non-physiological temperatures.

Heat shock protein expression as guidance for the therapeutic window of retinal laser therapy

NASA Astrophysics Data System (ADS)

Wang, Jenny; Huie, Philip; Dalal, Roopa; Lee, Seungjun; Tan, Gavin; Lee, Daeyoung; Lavinksy, Daniel; Palanker, Daniel

2016-03-01

Unlike conventional photocoagulation, non-damaging retinal laser therapy (NRT) limits laser-induced heating to stay below the retinal damage threshold and therefore requires careful dosimetry. Without the adverse effects associated with photocoagulation, NRT can be applied to critical areas of the retina and repeatedly to manage chronic disorders. Although the clinical benefits of NRT have been demonstrated, the mechanism of therapeutic effect and width of the therapeutic window below damage threshold are not well understood. Here, we measure activation of heat shock response via laser-induced hyperthermia as one indication of cellular response. A 577 nm laser is used with the Endpoint Management (EpM) user interface, a titration algorithm, to set experimental pulse energies relative to a barely visible titration lesion. Live/dead staining and histology show that the retinal damage threshold in rabbits is at 40% of titration energy on EpM scale. Heat shock protein 70 (HSP70) expression in the retinal pigment epithelium (RPE) was detected by whole-mount immunohistochemistry after different levels of laser treatment. We show HSP70 expression in the RPE beginning at 25% of titration energy indicating that there is a window for NRT between 25% and 40% with activation of the heat shock protein expression in response to hyperthermia. HSP70 expression is also seen at the perimeter of damaging lesions, as expected based on a computational model of laser heating. Expression area for each pulse energy setting varied between laser spots due to pigmentation changes, indicating the relatively narrow window of non-damaging activation and highlighting the importance of proper titration.

The inactivation of RNase G reduces the Stenotrophomonas maltophilia susceptibility to quinolones by triggering the heat shock response.

PubMed

Bernardini, Alejandra; Corona, Fernando; Dias, Ricardo; Sánchez, Maria B; Martínez, Jose L

2015-01-01

Quinolone resistance is usually due to mutations in the genes encoding bacterial topoisomerases. However, different reports have shown that neither clinical quinolone resistant isolates nor in vitro obtained Stenotrophomonas maltophilia mutants present mutations in such genes. The mechanisms so far described consist on efflux pumps' overexpression. Our objective is to get information on novel mechanisms of S. maltophilia quinolone resistance. For this purpose, a transposon-insertion mutant library was obtained in S. maltophilia D457. One mutant presenting reduced susceptibility to nalidixic acid was selected. Inverse PCR showed that the inactivated gene encodes RNase G. Complementation of the mutant with wild-type RNase G allele restored the susceptibility to quinolones. Transcriptomic and real-time RT-PCR analyses showed that several genes encoding heat-shock response proteins were expressed at higher levels in the RNase defective mutant than in the wild-type strain. In agreement with this situation, heat-shock reduces the S. maltophilia susceptibility to quinolone. We can then conclude that the inactivation of the RNase G reduces the susceptibility of S. maltophilia to quinolones, most likely by regulating the expression of heat-shock response genes. Heat-shock induces a transient phenotype of quinolone resistance in S. maltophilia.

Heat Stress Modulates Mycelium Growth, Heat Shock Protein Expression, Ganoderic Acid Biosynthesis, and Hyphal Branching of Ganoderma lucidum via Cytosolic Ca2+

PubMed Central

Zhang, Xue; Ren, Ang; Li, Meng-Jiao; Cao, Peng-Fei; Chen, Tian-Xi; Zhang, Guang; Shi, Liang; Jiang, Ai-Liang

2016-01-01

ABSTRACT Heat stress (HS) influences the growth and development of organisms. Thus, a comprehensive understanding of how organisms sense HS and respond to it is required. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system due to the complete sequencing of its genome, transgenic systems, and reliable reverse genetic tools. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced the accumulation of ganoderic acid biosynthesis and heat shock proteins (HSPs) in G. lucidum. Our data showed that HS induced a significant increase in cytosolic Ca2+ concentration. Further evidence showed that Ca2+ might be a factor in the HS-mediated regulation of hyphal branching, ganoderic acid (GA) biosynthesis, and the accumulation of HSPs. Our results further showed that the calcium-permeable channel gene (cch)-silenced and phosphoinositide-specific phospholipase gene (plc)-silenced strains reduced the HS-induced increase in HSP expression compared with that observed for the wild type (WT). This study demonstrates that cytosolic Ca2+ participates in heat shock signal transduction and regulates downstream events in filamentous fungi. IMPORTANCE Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system for evaluating how environmental factors regulate the development and secondary metabolism of basidiomycetes. Heat stress (HS) is an important environmental challenge. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced HSP expression and ganoderic acid biosynthesis in G. lucidum. Further evidence showed that Ca2+ might be a factor in the HS-mediated regulation of hyphal branching, GA biosynthesis, and the accumulation of HSPs. This study demonstrates that cytosolic Ca2+ participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Our research

Heat Stress Modulates Mycelium Growth, Heat Shock Protein Expression, Ganoderic Acid Biosynthesis, and Hyphal Branching of Ganoderma lucidum via Cytosolic Ca2.

PubMed

Zhang, Xue; Ren, Ang; Li, Meng-Jiao; Cao, Peng-Fei; Chen, Tian-Xi; Zhang, Guang; Shi, Liang; Jiang, Ai-Liang; Zhao, Ming-Wen

2016-07-15

Heat stress (HS) influences the growth and development of organisms. Thus, a comprehensive understanding of how organisms sense HS and respond to it is required. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system due to the complete sequencing of its genome, transgenic systems, and reliable reverse genetic tools. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced the accumulation of ganoderic acid biosynthesis and heat shock proteins (HSPs) in G. lucidum Our data showed that HS induced a significant increase in cytosolic Ca(2+) concentration. Further evidence showed that Ca(2+) might be a factor in the HS-mediated regulation of hyphal branching, ganoderic acid (GA) biosynthesis, and the accumulation of HSPs. Our results further showed that the calcium-permeable channel gene (cch)-silenced and phosphoinositide-specific phospholipase gene (plc)-silenced strains reduced the HS-induced increase in HSP expression compared with that observed for the wild type (WT). This study demonstrates that cytosolic Ca(2+) participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system for evaluating how environmental factors regulate the development and secondary metabolism of basidiomycetes. Heat stress (HS) is an important environmental challenge. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced HSP expression and ganoderic acid biosynthesis in G. lucidum Further evidence showed that Ca(2+) might be a factor in the HS-mediated regulation of hyphal branching, GA biosynthesis, and the accumulation of HSPs. This study demonstrates that cytosolic Ca(2+) participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Our research offers a new

Precise new shock temperatures in forsterite and in silicate liquids: phase transitions and heat capacity at high pressure

NASA Astrophysics Data System (ADS)

Asimow, P. D.; Fat'yanov, O. V.; Su, C.; Ma, X. J.

2017-12-01

Shock temperature measurements in transparent samples provide key constraints on the phase transitions and thermodynamic properties of materials at high pressure and temperature. Such measurements are necessary, for example, to allow equation of state measurements taken along the Hugoniot to be translated to P-V-T space. We have recently completed a detailed study of the accuracy and reproducibility of calibration of our 6-channel fast pyrometer. We have also introduced improved analysis procedures of the time-dependent multi-wavelength radiance signal that avoid the need for a greybody assumption and therefore have better precision than earlier results. This has motivated (a) renewed study of the shock temperature of forsterite in the superheating, partial melting, and complete melting regimes, (b) pre-heated diopside-anorthite glass shock temperature experiments for comparison to pre-heated silicate liquid equation of state results, and (c) new soda-lime glass shock temperature experiments. Single-crystal synthetic forsterite samples were shocked along (100) to pressures between 120 and 210 GPa on the Caltech two-stage light gas gun. Uncertainties on most results are 50 K. Results above the onset of partial melting at 130 GPa are consistent with Lyzenga and Ahrens (1980) data and show a low P-T slope consistent with a partial melting interval. Complete melting may occur, given sufficient time, at about 210 GPa. The experiment at 120-130 GPa is anomalous, showing two-wave structure and time- and wavelength-dependent scattering suggesting a subsolidus phase transition behind the shock front. The amount of super-heating, if any, is far smaller than claimed by Holland and Ahrens (1997). Steady radiation profiles, high emissivity, and consistency from channel to channel provide high precision (±40 K) in diopside-anorthite liquid shocked from just above the glass transition to high pressure. Temperatures are colder than expected for a model with constant heat capacity

An alternatively spliced heat shock transcription factor, OsHSFA2dI, functions in the heat stress-induced unfolded protein response in rice.

PubMed

Cheng, Q; Zhou, Y; Liu, Z; Zhang, L; Song, G; Guo, Z; Wang, W; Qu, X; Zhu, Y; Yang, D

2015-03-01

As sessile organisms, plants have evolved a wide range of defence pathways to cope with environmental stress such as heat shock. However, the molecular mechanism of these defence pathways remains unclear in rice. In this study, we found that OsHSFA2d, a heat shock transcriptional factor, encodes two main splice variant proteins, OsHSFA2dI and OsHSFA2dII in rice. Under normal conditions, OsHSFA2dII is the dominant but transcriptionally inactive spliced form. However, when the plant suffers heat stress, OsHSFA2d is alternatively spliced into a transcriptionally active form, OsHSFA2dI, which participates in the heat stress response (HSR). Further study found that this alternative splicing was induced by heat shock rather than photoperiod. We found that OsHSFA2dI is localised to the nucleus, whereas OsHSFA2dII is localised to the nucleus and cytoplasm. Moreover, expression of the unfolded protein response (UNFOLDED PROTEIN RESPONSE) sensors, OsIRE1, OsbZIP39/OsbZIP60 and the UNFOLDED PROTEIN RESPONSE marker OsBiP1, was up-regulated. Interestingly, OsbZIP50 was also alternatively spliced under heat stress, indicating that UNFOLDED PROTEIN RESPONSE signalling pathways were activated by heat stress to re-establish cellular protein homeostasis. We further demonstrated that OsHSFA2dI participated in the unfolded protein response by regulating expression of OsBiP1. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Heat shock protein 70 inhibits cardiomyocyte necroptosis through repressing autophagy in myocardial ischemia/reperfusion injury.

PubMed

Liu, Xiaojuan; Zhang, Chao; Zhang, Chi; Li, Jingjing; Guo, Wanwan; Yan, Daliang; Yang, Chen; Zhao, Jianhua; Xia, Tian; Wang, Yuqing; Xu, Rong; Wu, Xiang; Shi, Jiahai

2016-06-01

Irreversible damage of cardiac function arisen from myocardial ischemia/reperfusion injury (MIRI) leads to an emerging challenge in the treatments of cardiac ischemic diseases. Molecular chaperone heat shock protein 70 (HSP70) attenuates heat-stimulated cell autophagy, apoptosis, and damage in the heart. Under specific conditions, autophagy may, directly or indirectly, induce cell death including necroptosis. Whether HSP70 inhibits cardiomyocyte necroptosis via suppressing autophagy during MIRI is unknown. In our study, HSP70 expression was opposite to necroptosis marker RIP1 and autophagy marker LC3A/B expression after myocardial ischemia/reperfusion (MIR) in vivo. Furthermore, in vitro primary rat cardiomyocytes mimicked MIRI by hypoxia/reoxygenation (H/R) treatment. Knockdown of HSP70 expression promoted cardiomyocyte autophagy and necroptosis following H/R treatment, while the increase tendency was downregulated by autophagy inhibitor 3-MA, showing that autophagy-induced necroptosis could be suppressed by HSP70. In summary, HSP70 downregulates cardiomyocyte necroptosis through suppressing autophagy during myocardial IR, revealing the novel protective mechanism of HSP70 and supplying a novel molecular target for the treatment of heart ischemic diseases.

Regulation of the heat shock response under anoxia in the turtle, Trachemys scripta elegans.

PubMed

Krivoruchko, Anastasia; Storey, Kenneth B

2010-03-01

The effects of 20 h of anoxic submergence in cold water and 5 h of aerobic recovery on the heat shock response were analyzed in four organs of the anoxia-tolerant turtle Trachemys scripta elegans. Immunoblotting was used to analyze levels of active and inactive forms of the heat shock transcription factor 1 (HSF1), nuclear translocation of HSF1, and the levels of six heat shock proteins (HSPs). PCR was also used to retrieve the turtle HSF1 nucleotide sequence; its deduced amino acid sequence showed 97% identity with chicken HSF1. White skeletal muscle showed a strong fivefold increase in the amount of active HSF1 under anoxic conditions as well as an 80% increase in nuclear localization. This was accompanied by upregulation of five HSPs by 1.8- to 2.9-fold: Hsp25, Hsp40, Hsp70, Hsc70, and Hsp90, the latter two remained elevated after 5 h of aerobic recovery. Kidney and liver showed little change in active HSF1 content during anoxia and recovery, but a significant increase in the nuclear localization of HSF1 during anoxia. This supported enhanced expression of three HSPs in kidney (Hsp40, Hsc70, and Hsp90) and four in liver (Hsp40, Hsp60, Hsp70, Hsc70). Heart displayed a strong increase in active HSF1 during anoxia and recovery (6.6- to 6.8-fold higher than control) and increased nuclear localization but heart HSP levels did not rise. The data demonstrate organ-specific regulation of HSPs during anoxia exposure and aerobic recovery in T. s. elegans and suggest that the heat shock response is an important aspect of cytoprotection during facultative anaerobiosis, particularly with regard to underwater hibernation of turtles in cold water.

Ion Heating and Thermalization in a 3000 km/s Shock

NASA Astrophysics Data System (ADS)

Raymond, J. C.; Winkler, P. F.; Blair, W. P.; Laming, J. M.

2017-12-01

Collisionless shock waves can leave the plasma far from thermal equilibrium. Each particle species may have a different temperature, and the velocity distributions may be far from Maxwellian. We present HST/COS observations and MAGELLAN/IMACS of a 3000 km/s shock in the supernova remnant SN1006. The UV lines of He, C and N and the Hα profile show that the temperatures of H, He, C and N are mass-proportional to within the observational uncertainties. Thus there is no strong preferential heating and no strong transfer of energy among the ions. The electron temperature is about 0.05 as large as the proton temperature, and the H I distribution is non-Maxwellian. We briefly compare the results with theoretical expectations.

Studies of shock/shock interaction on smooth and transpiration-cooled hemispherical nosetips in hypersonic flow

NASA Technical Reports Server (NTRS)

Holden, Michael S.; Rodriguez, Kathleen M.

1992-01-01

A program of experimental research and analysis was conducted to examine the heat transfer and pressure distributions in regions of shock/shock interaction over smooth and transpiration-cooled hemispherical noseshapes. The objective of this investigation was to determine whether the large heat transfer generated in regions of shock/shock interaction can be reduced by transpiration cooling. The experimental program was conducted at Mach numbers of 12 to 16 in the Calspan 48-Inch Shock Tunnel. Type 3 and type 4 interaction regions were generated for a range of freestream unit Reynolds numbers to provide shear layer Reynolds numbers from 10 exp 4 to 10 exp 6 to enable laminar and turbulent interaction regions to be studied. Shock/shock interactions were investigated on a smooth hemispherical nosetip and a similar transpiration-cooled nosetip, with the latter configuration being examined for a range of surface blowing rates up to one-third of the freestream mass flux. While the heat transfer measurements on the smooth hemisphere without shock/shock interaction were in good agreement with Fay-Riddell predictions, those on the transpiration-cooled nosetip indicated that its intrinsic roughness caused heating-enhancement factors of over 1.5. In the shock/shock interaction studies on the smooth nosetip, detailed heat transfer and pressure measurements were obtained to map the variation of the distributions with shock-impingement position for a range of type 3 and type 4 interactions. Such sets of measurements were obtained for a range of unit Reynolds numbers and Mach numbers to obtain both laminar and turbulent interactions. The measurements indicated that shear layer transition has a significant influence on the heating rates for the type 4 interaction as well as the anticipated large effects on type 3 interaction heating. In the absence of blowing, the peak heating in the type 3 and type 4 interaction regions, over the transpiration-cooled model, did not appear to be

Evaporation and Accompanying Isotopic Fractionation of Sulfur from FE-S Melt During Shock Wave Heating

NASA Technical Reports Server (NTRS)

Tachibana, S.; Huss, G. R.; Miura, H.; Nakamoto, T.

2004-01-01

Chondrules probably formed by melting and subsequent cooling of solid precursors. Evaporation during chondrule melting may have resulted in depletion of volatile elements in chondrules. It is known that kinetic evaporation, especially evaporation from a melt, often leads to enrichment of heavy isotopes in an evaporation residue. However, no evidence for a large degree of heavy-isotope enrichment has been reported in chondrules for K, Mg, Si, and Fe (as FeO). The lack of isotopic fractionation has also been found for sulfur in troilites (FeS) within Bishunpur (LL3.1) and Semarkona (LL3.0) chondrules by an ion microprobe study. The largest fractionation, found in only one grain, was 2.7 +/- 1.4 %/amu, while all other troilite grains showed isotopic fractionations of <1 %/amu. The suppressed isotopic fractionation has been interpreted as results of (i) rapid heating of precursors at temperatures below the silicate solidus and (ii) diffusion-controlled evaporation through a surrounding silicate melt at temperatures above the silicate solidus. The kinetic evaporation model suggests that a rapid heating rate of >10(exp 4)-10(exp 6) K/h for a temperature range of 1000-1300 C is required to explain observed isotopic fractionations. Such a rapid heating rate seems to be difficult to be achieved in the X-wind model, but can be achieved in shock wave heating models. In this study, we have applied the sulfur evaporation model to the shock wave heating conditions of to evaluate evaporation of sulfur and accompanying isotopic fractionation during shock wave heating at temperatures below the silicate solidus.

Experimental study of pressure and heating rate on a swept cylindrical leading edge resulting from swept shock wave interference. M.S. Thesis

NASA Technical Reports Server (NTRS)

Glass, Christopher E.

1989-01-01

The effects of cylindrical leading edge sweep on surface pressure and heat transfer rate for swept shock wave interference were investigated. Experimental tests were conducted in the Calspan 48-inch Hypersonic Shock Tunnel at a nominal Mach number of 8, nominal unit Reynolds number of 1.5 x 10 to the 6th power per foot, leading edge and incident shock generator sweep angles of 0, 15, and 30 deg, and incident shock generator angle-of-attack fixed at 12.5 deg. Detailed surface pressure and heat transfer rate on the cylindircal leading edge of a swept shock wave interference model were measured at the region of the maximum surface pressure and heat transfer rate. Results show that pressure and heat transfer rate on the cylindrical leading edge of the shock wave interference model were reduced as the sweep was increased over the range of tested parameters. Peak surface pressure and heat transfer rate on the cylinder were about 10 and 30 times the undisturbed flow stagnation point value, respectively, for the 0 deg sweep test. A comparison of the 15 and 30 deg swept results with the 0 deg swept results showed that peak pressure was reduced about 13 percent and 44 percent, respectively, and peak heat transfer rate was reduced about 7 percent and 27 percent, respectively.

Heat Shock Factor 1: From Fire Chief to Crowd-Control Specialist.

PubMed

Triandafillou, Catherine G; Drummond, D Allan

2016-07-07

HSF1 is the supposed master regulator of the heat shock response. In this issue of Molecular Cell, Solís et al. reveal that it has a much narrower job description: organizing a small team of molecular chaperones that keep the proteome moving. Copyright © 2016 Elsevier Inc. All rights reserved.

LCM-seq reveals the crucial role of LsSOC1 in heat-promoted bolting of lettuce (Lactuca sativa L.).

PubMed

Chen, Zijing; Zhao, Wensheng; Ge, Danfeng; Han, Yingyan; Ning, Kang; Luo, Chen; Wang, Shenglin; Liu, Renyi; Zhang, Xiaolan; Wang, Qian

2018-05-17

Lettuce (Lactuca sativa L.) is one of the most economically important vegetables. The floral transition in lettuce is accelerated under high temperatures, which can significantly decrease yields. However, the molecular mechanism underlying the floral tranition in lettuce is poorly known. Using laser capture microdissection coupled with RNA sequencing, we isolated shoot apical meristem cells from the bolting-sensitive lettuce line S39 at four critical stages of development. Subsequently, we screened specifically for the flowering-related gene LsSOC1 during the floral transition through comparative transcriptomic analysis. Molecular biology, developmental biology, and biochemical tools were combined to investigate the biological function of LsSOC1 in lettuce. LsSOC1 knockdown by RNA interference resulted in a significant delay in the timing of bolting and insensitivity to high temperature, which indicated that LsSOC1 functions as an activator during heat-promoted bolting in lettuce. We determined that two heat-shock transcription factors, HsfA1e and HsfA4c, bound to the promoter of LsSOC1 to confirm that LsSOC1 played an important role in heat-promoted bolting. This study indicates that LsSOC1 plays a crucial role in the heat-promoted bolting process in lettuce. Further investigation of LsSOC1 may be useful for clarification of the bolting mechanism in lettuce. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Intra-binary Shock Heating of Black Widow Companions

NASA Astrophysics Data System (ADS)

Romani, Roger W.; Sanchez, Nicolas

2016-09-01

The low-mass companions of evaporating binary pulsars (black widows and similar) are strongly heated on the side facing the pulsar. However, in high-quality photometric and spectroscopic data, the heating pattern does not match that expected for direct pulsar illumination. Here we explore a model where the pulsar power is intercepted by an intra-binary shock (IBS) before heating the low-mass companion. We develop a simple analytic model and implement it in the popular “ICARUS” light curve code. The model is parameterized by the wind momentum ratio β and the companion wind speed {f}v{v}{{orb}}, and assumes that the reprocessed pulsar wind emits prompt particles or radiation to heat the companion surface. We illustrate an interesting range of light curve asymmetries controlled by these parameters. The code also computes the IBS synchrotron emission pattern, and thus can model black widow X-ray light curves. As a test, we apply the results to the high-quality asymmetric optical light curves of PSR J2215+5135; the resulting fit gives a substantial improvement upon direct heating models and produces an X-ray light curve consistent with that seen. The IBS model parameters imply that at the present loss rate, the companion evaporation has a characteristic timescale of {τ }{{evap}}≈ 150 Myr. Still, the model is not fully satisfactory, indicating that there are additional unmodeled physical effects.

Modification of N6-methyladenosine RNA methylation on heat shock protein expression.

PubMed

Yu, Jiayao; Li, Yi; Wang, Tian; Zhong, Xiang

2018-01-01

This study was conducted to investigate effect of N6-methyladenosine (m6A) RNA methylation on Heat shock proteins (HSPs) and dissect the profile of HSP RNA methylation. The results showed that m6A methyltransferases METTL3 mRNA was decreased in responses to heat shock stress in HepG2 cells, but m6A-specific binding protein YTHDF2 mRNA was upregulated in a manner similar to HSP70 induction. Immunofluorescence staining showed that the majority of YTHDF2 was present in the cytosol, however, nearly all YTHDF2 translocated from the cytosol into the nucleus after heat shock. METTL3 knockdown significantly changed HSP70, HSP60, and HSP27 mRNA expression in HepG2 cells using siRNA, however, mRNA lifetime was not impacted. Silence of YTHDF2 using siRNA did not change expression of HSP70, but significantly increased HSP90, HSP60, and HSPB1 mRNA expression. In addition, m6A-seq revealed that HSP m6A methylation peaks are mainly enriched on exons and around stop codons, and shows a unique distribution profile in the 5'UTR and 3'UTR. Knockdown of METTL3 changed the methylation patterns of HSPs transcript. In conclusion, m6A RNA methylation regulates HSP gene expression. Differential expression of HSPs modulated by m6A may depend on the m6A site and abundance of the target gene. This finding provides insights into new regulatory mechanisms of HSPs in normal and stress situations.

Serum heat shock protein 70 level as a biomarker of exceptional longevity.

PubMed

Terry, Dellara F; Wyszynski, Diego F; Nolan, Vikki G; Atzmon, Gil; Schoenhofen, Emily A; Pennington, JaeMi Y; Andersen, Stacy L; Wilcox, Marsha A; Farrer, Lindsay A; Barzilai, Nir; Baldwin, Clinton T; Asea, Alexzander

2006-11-01

Heat shock proteins are highly conserved proteins that, when produced intracellularly, protect stress exposed cells. In contrast, extracellular heat shock protein 70 (Hsp70) has been shown to have both protective and deleterious effects. In this study, we assessed heat shock protein 70 for its potential role in human longevity. Because of the importance of HSP to disease processes, cellular protection, and inflammation, we hypothesized that: (1) Hsp70 levels in centenarians and centenarian offspring are different from controls and (2) alleles in genes associated with Hsp70 explain these differences. In this cross-sectional study, we assessed serum Hsp70 levels from participants enrolled in either the New England Centenarian Study (NECS) or the Longevity Genes Project (LGP): 87 centenarians (from LGP), 93 centenarian offspring (from NECS), and 126 controls (43 from NECS, 83 from LGP). We also examined genotypic and allelic frequencies of polymorphisms in HSP70-A1A and HSP70-A1B in 347 centenarians (266 from the NECS, 81 from the LGP), 260 NECS centenarian offspring, and 238 controls (NECS: 53 spousal controls and 106 septuagenarian offspring controls; LGP: 79 spousal controls). The adjusted mean serum Hsp70 levels (ng/mL) for the NECS centenarian offspring, LGP centenarians, LGP spousal controls, and NECS controls were 1.05, 1.13, 3.07, 6.93, respectively, suggesting that a low serum Hsp70 level is associated with longevity; however, no genetic associations were found with two SNPs within two hsp70 genes.

Altered phosphorylation of. tau. protein in heat-shocked rats and patients with Alzheimer disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papasozomenos, S.C.; Yuan Su

1991-05-15

Six hours after heat shocking 2- to 3-month-old male and female Sprague-Dawley rats at 42C for 15 min, the authors analyzed {tau} protein immunoreactivity in SDS extracts of cerebrums and peripheral nerves by using immunoblot analysis and immunohistochemistry with the anti-{tau} monoclonal antibody Tau-1, which recognizes a phosphate-dependent nonphosphorylated epitope, and with {sup 125}I-labeled protein A. In the cerebal extracts, the authors found altered phosphorylation of {tau} in heat-shocked females, characterized by a marked reduction in the amount of nonphosphorylated {tau}, a doubling of the ratio of total (phosphorylated plus nonphosphorylated) {tau} to nonphosphorylated {tau}, and the appearance of themore » slowest moving phosphorylated {tau} polypeptide (68 kDa). Similar, but milder, changes were observed in male rats. Quantitative immunoblot analysis of cortex and the underlying white matter with Tau-1 and {sup 125}I-labeled protein A showed that the amount of phosphorylated {tau} progressively increased in the Alzheimer disease-affected cerebral cortex, while concurrently a proportionally lesser amount of {tau} entered the white matter axons. The similar findings for the rat heat-shock model and Alzheimer disease suggest that life stressors may play a role in the etiopathogenesis of Alzheimer's disease.« less

The heat-shock protein/chaperone network and multiple stress resistance.

PubMed

Jacob, Pierre; Hirt, Heribert; Bendahmane, Abdelhafid

2017-04-01

Crop yield has been greatly enhanced during the last century. However, most elite cultivars are adapted to temperate climates and are not well suited to more stressful conditions. In the context of climate change, stress resistance is a major concern. To overcome these difficulties, scientists may help breeders by providing genetic markers associated with stress resistance. However, multistress resistance cannot be obtained from the simple addition of single stress resistance traits. In the field, stresses are unpredictable and several may occur at once. Consequently, the use of single stress resistance traits is often inadequate. Although it has been historically linked with the heat stress response, the heat-shock protein (HSP)/chaperone network is a major component of multiple stress responses. Among the HSP/chaperone 'client proteins', many are primary metabolism enzymes and signal transduction components with essential roles for the proper functioning of a cell. HSPs/chaperones are controlled by the action of diverse heat-shock factors, which are recruited under stress conditions. In this review, we give an overview of the regulation of the HSP/chaperone network with a focus on Arabidopsis thaliana. We illustrate the role of HSPs/chaperones in regulating diverse signalling pathways and discuss several basic principles that should be considered for engineering multiple stress resistance in crops through the HSP/chaperone network. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Picornavirus proteins share antigenic determinants with heat shock proteins 60/65.

PubMed

Härkönen, T; Puolakkainen, M; Sarvas, M; Airaksinen, U; Hovi, T; Roivainen, M

2000-11-01

Immunological cross-reactions between enteroviruses and islet cell autoantigens have been suggested to play a role in the etiopathogenesis of insulin dependent diabetes mellitus (IDDM). In the nonobese diabetic mouse, an autoimmune model of IDDM, one of the reactive beta cell autoantigens is the heat shock protein 60 (HSP60). These studies were prompted by sequence homology discovered between the immunogenic region in HSP60 and two regions in enterovirus capsid proteins, one in the VP1 protein and the other in the VP0, the precursor of VP2 and VP4 proteins. Possible immunological cross-reactions between enterovirus proteins and heat shock proteins were studied by EIA and immunoblotting by using purified virus preparations, viral expression proteins VP1 and VP0, and recombinant HSP60/65 proteins, and corresponding polyclonal antisera. The HSP60/65 family of proteins is highly conserved and there is a striking degree of homology between bacterial and human heat shock proteins. Rabbit antibodies to HSP65 of Mycobacterium bovis that reacted with human HSP60 were also found to recognise capsid protein VP1 of coxsackievirus A9, VP1, and/or VP2 of coxsackievirus B4. Both viruses were also recognised by antisera raised against HSP60 of Chlamydia pneumoniae. In addition to the capsid proteins derived from native virions, antisera to both bacterial HSP proteins recognised expression protein VP1 of coxsackievirus A9. The cross-reactivity was also demonstrated the other way around; antisera to purified virus particles reacted with the HSP 60/65 proteins to some extent. These results suggest that apart from the well-documented sequence homology between the 2C protein of coxsackieviruses and the beta-cell autoantigen glutamic acid decarboxylase, there are other motifs in picornavirus proteins homologous to islet cell autoantigens, which might induce cross-reacting immune responses during picornavirus infections.

Radio frequency induced hyperthermia mediated by dextran stabilized LSMO nanoparticles: in vitro evaluation of heat shock protein response

NASA Astrophysics Data System (ADS)

Bhayani, K. R.; Rajwade, J. M.; Paknikar, K. M.

2013-01-01

Dextran stabilized La0.7Sr0.3MnO3 (Dex-LSMO) is an alternative cancer hyperthermia agent holding considerable promise. Here, we have carried out a comparative study on radio frequency (˜264 kHz) induced Dex-LSMO mediated heating and extraneous heating (mimicking generalized hyperthermia) in terms of changes in the morphology, proliferation pattern and induction of heat shock proteins in a human melanoma cell line (A375). Our results clearly show that the cellular effects seen with extraneous heating (60 min at 43 °C) could be reproduced by just six minutes of radio frequency induced Dex-LSMO mediated heating. More importantly, the observed enhanced levels of HSP 70 and 90 (molecular markers of heat shock that trigger favorable immunological reactions) seen with Dex-LSMO mediated heating were comparable to extraneous heating. These results suggest the possible utility of Dex-LSMO as a cancer hyperthermia agent.

Crystal structure of a small heat-shock protein from Xylella fastidiosa reveals a distinct high-order structure.

PubMed

Fonseca, Emanuella Maria Barreto; Scorsato, Valéria; Dos Santos, Marcelo Leite; Júnior, Atilio Tomazini; Tada, Susely Ferraz Siqueira; Dos Santos, Clelton Aparecido; de Toledo, Marcelo Augusto Szymanski; de Souza, Anete Pereira; Polikarpov, Igor; Aparicio, Ricardo

2017-04-01

Citrus variegated chlorosis is a disease that attacks economically important citrus plantations and is caused by the plant-pathogenic bacterium Xylella fastidiosa. In this work, the structure of a small heat-shock protein from X. fastidiosa (XfsHSP17.9) is reported. The high-order structures of small heat-shock proteins from other organisms are arranged in the forms of double-disc, hollow-sphere or spherical assemblies. Unexpectedly, the structure reported here reveals a high-order architecture forming a nearly square cavity.

Translational induction of heat shock transcription factor σ32: evidence for a built-in RNA thermosensor

PubMed Central

Morita, Miyo Terao; Tanaka, Yoshiyuki; Kodama, Takashi S.; Kyogoku, Yoshimasa; Yanagi, Hideki; Yura, Takashi

1999-01-01

Induction of heat shock proteins in Escherichia coli is primarily caused by increased cellular levels of the heat shock σ-factor σ32 encoded by the rpoH gene. Increased σ32 levels result from both enhanced synthesis and stabilization. Previous work indicated that σ32 synthesis is induced at the translational level and is mediated by the mRNA secondary structure formed within the 5′-coding sequence of rpoH, including the translation initiation region. To understand the mechanism of heat induction of σ32 synthesis further, we analyzed expression of rpoH–lacZ gene fusions with altered stability of mRNA structure before and after heat shock. A clear correlation was found between the stability and expression or the extent of heat induction. Temperature-melting profiles of mRNAs with or without mutations correlated well with the expression patterns of fusion genes carrying the corresponding mutations in vivo. Furthermore, temperature dependence of mRNA–30S ribosome–tRNAfMet complex formation with wild-type or mutant mRNAs in vitro agreed well with that of the expression of gene fusions in vivo. Our results support a novel mechanism in which partial melting of mRNA secondary structure at high temperature enhances ribosome entry and translational initiation without involvement of other cellular components, that is, intrinsic mRNA stability controls synthesis of a transcriptional regulator. PMID:10090722

Genes for Drosophila small heat shock proteins are regulated differently by ecdysterone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amin, J.; Voellmy, R.; Mestril, R.

Genes for small heat shock proteins (hsp27 to hsp22) are activated in late third-instar larvae of Drosophila melanogaster in the absence of heat stress. This regulation has been stimulated in cultured Drosophila cells in which the genes are activated by the addition of ecdysterone. Sequence elements (HERE) involved in ecdysterone regulation of the hsp27 and hsp23 genes have been defined by transfection studies and have recently been identified as binding sites for ecdysterone receptor. The authors report here that the shp27 and hsp23 genes are regulated differently by ecdysterone. The hsp27 gene is activated rapidly by ecdysterone, even in themore » absence of protein synthesis. In contrast, high-level expression of the hsp23 gene begins only after a lag of about 6 h, is dependent on the continuous presence of ecdysterone, and is sensitive to low concentrations of protein synthesis inhibitors. Transfection experiments with reported constructs show that this difference in regulation is at the transcriptional level. Synthetic hsp27 or hsp23 HERE sequences confer hsp27- or hsp23-type ecdysterone regulation on a basal promoter. These findings indicate that the hsp27 gene is primary, and the hsp23 gene is mainly a secondary, hormone-responsive gene. Ecdysterone receptor is implied to play a role in the regulation of both genes.« less

Racemization of Valine by Impact-Induced Heating

NASA Astrophysics Data System (ADS)

Furukawa, Yoshihiro; Takase, Atsushi; Sekine, Toshimori; Kakegawa, Takeshi; Kobayashi, Takamichi

2018-03-01

Homochirality plays an important role in all living organisms but its origin remains unclear. It also remains unclear whether such chiral molecules survived terrestrial heavy impact events. Impacts of extraterrestrial objects on early oceans were frequent and could have affected the chirality of oceanic amino acids when such amino acids accumulated during impacts. This study investigated the effects of shock-induced heating on enantiomeric change of valine with minerals such as olivine ([Mg0.9, Fe0.1]2SiO4), hematite (Fe2O3), and calcite (CaCO3). With a shock wave generated by an impact at 0.8 km/s, both d- and l-enriched valine were significantly decomposed and partially racemized under all experimental conditions. Different minerals had different shock impedances; therefore, they provided different P-T conditions for identical impacts. Furthermore, the high pH of calcite promoted the racemization of valine. The results indicate that in natural hypervelocity impacts, amino acids in shocked oceanic water would have decomposed completely, since impact velocity and the duration of shock compression and heating are typically greater in hypervelocity impact events than those in experiments. Even with the shock wave by the impact of small and decelerated projectiles in which amino acids survive, the shock heating may generate sufficient heat for significant racemization in shocked oceanic water. However, the duration of shock induced heating by small projectiles is limited and the population of such decelerated projectiles would be limited. Therefore, even though impacts of asteroids and meteorites were frequent on the prebiotic Earth, impact events would not have significantly changed the ee of proteinogenic amino acids accumulated in the entire ocean.

Arabidopsis HEAT SHOCK TRANSCRIPTION FACTORA1b overexpression enhances water productivity, resistance to drought, and infection

PubMed Central

Richard, François; Bowden, Laura; Morison, James I.L.; Mullineaux, Philip M.

2013-01-01

Heat-stressed crops suffer dehydration, depressed growth, and a consequent decline in water productivity, which is the yield of harvestable product as a function of lifetime water consumption and is a trait associated with plant growth and development. Heat shock transcription factor (HSF) genes have been implicated not only in thermotolerance but also in plant growth and development, and therefore could influence water productivity. Here it is demonstrated that Arabidopsis thaliana plants with increased HSFA1b expression showed increased water productivity and harvest index under water-replete and water-limiting conditions. In non-stressed HSFA1b-overexpressing (HSFA1bOx) plants, 509 genes showed altered expression, and these genes were not over-represented for development-associated genes but were for response to biotic stress. This confirmed an additional role for HSFA1b in maintaining basal disease resistance, which was stress hormone independent but involved H2O2 signalling. Fifty-five of the 509 genes harbour a variant of the heat shock element (HSE) in their promoters, here named HSE1b. Chromatin immunoprecipitation-PCR confirmed binding of HSFA1b to HSE1b in vivo, including in seven transcription factor genes. One of these is MULTIPROTEIN BRIDGING FACTOR1c (MBF1c). Plants overexpressing MBF1c showed enhanced basal resistance but not water productivity, thus partially phenocopying HSFA1bOx plants. A comparison of genes responsive to HSFA1b and MBF1c overexpression revealed a common group, none of which harbours a HSE1b motif. From this example, it is suggested that HSFA1b directly regulates 55 HSE1b-containing genes, which control the remaining 454 genes, collectively accounting for the stress defence and developmental phenotypes of HSFA1bOx. PMID:23828547

Metal ions induced heat shock protein response by elevating superoxide anion level in HeLa cells transformed by HSE-SEAP reporter gene.

PubMed

Yu, Zhanjiang; Yang, Xiaoda; Wang, Kui

2006-06-01

The aim of this work is to define the relationship between heat shock protein (HSP) and reactive oxygen species (ROS) in the cells exposed to different concentrations of metal ions, and to evaluate a new method for tracing the dynamic levels of cellular reactive oxygen species using a HSE-SEAP reporter gene. The expression of heat shock protein was measured using a secreted alkaline phosphatase (SEAP) reporter gene transformed into HeLa cell strain, the levels of superoxide anion (O(2)(-)) and hydrogen peroxide (H(2)O(2)) were determined by NBT reduction assay and DCFH staining flow cytometry (FCM), respectively. The experimental results demonstrated that the expression of heat shock protein induced by metal ions was linearly related to the cellular superoxide anion level before cytotoxic effects were observed, but not related to the cellular hydrogen peroxide level. The experimental results suggested that metal ions might induce heat shock protein by elevating cellular superoxide anion level, and thus the expression of heat shock protein indicated by the HSE-SEAP reporter gene can be an effective model for monitoring the dynamic level of superoxide anion and early metal-induced oxidative stress/cytotoxicity.

Endogenous Heat-Shock Protein Induction with or Without Radiofrequency Ablation or Cryoablation in Patients with Stage IV Melanoma.

PubMed

Domingo-Musibay, Evidio; Heun, James M; Nevala, Wendy K; Callstrom, Matthew; Atwell, Thomas; Galanis, Evanthia; Erickson, Lori A; Markovic, Svetomir N

2017-09-01

Percutaneous thermal ablation combined with in situ granulocyte-macrophage colony-stimulating factor cytokine therapy was technically feasible and well tolerated.No significant clinical or immunologic responses were seen. Melanoma tumor-derived heat-shock proteins (HSPs) and HSP-peptide complexes can elicit protective antitumor responses. The granulocyte-macrophage colony-stimulating factor (GM-CSF) chemokine can also promote uptake and processing by professional antigen presenting cells (APCs). On this basis, we designed a pilot study of percutaneous thermal ablation as a means to induce heat-shock protein vaccination plus GM-CSF to determine safety and preliminary antitumor activity of this combination. This study was designed to assess overall safety of percutaneous ablation combined with GM-CSF for unresectable, metastatic melanoma including uveal and mucosal types. All patients received heat-shock therapy (42°C for 30 minutes), then received one of three treatments: (a) intralesional GM-CSF (500 mcg standard dose); (b) radiofrequency ablation (RFA) + GM-CSF; or (c) cryoablation plus GM-CSF. The primary endpoint of the study was the induction of endogenous HSP70 and melanoma-specific cytotoxic T lymphocytes (CTL). Nine patients (three per study arm) were enrolled. No dose-limiting toxicity was observed as specified per protocol. All patients developed progressive disease and went on to receive alternative therapy. Median overall survival (OS) was 8.2 months (95% confidence interval [CI] 2-17.2). The study was not powered to detect a difference in clinical outcome among treatment groups. Percutaneous thermal ablation plus GM-CSF was well tolerated, technically feasible, and demonstrated an acceptable adverse event profile comparable to conventional RFA and cryoablation. While HSP70 was induced following therapy, the degree of HSP70 elevation was not associated with clinical outcome or induced CTL responses. While percutaneous thermal ablation plus GM

Sequence and structure determinants of Drosophila Hsp70 mRNA translation: 5'UTR secondary structure specifically inhibits heat shock protein mRNA translation.

PubMed Central

Hess, M A; Duncan, R F

1996-01-01

Preferential translation of Drosophila heat shock protein 70 (Hsp70) mRNA requires only the 5'-untranslated region (5'-UTR). The sequence of this region suggests that it has relatively little secondary structure, which may facilitate efficient protein synthesis initiation. To determine whether minimal 5'-UTR secondary structure is required for preferential translation during heat shock, the effect of introducing stem-loops into the Hsp70 mRNA 5'-UTR was measured. Stem-loops of -11 kcal/mol abolished translation during heat shock, but did not reduce translation in non-heat shocked cells. A -22 kcal/mol stem-loop was required to comparably inhibit translation during growth at normal temperatures. To investigate whether specific sequence elements are also required for efficient preferential translation, deletion and mutation analyses were conducted in a truncated Hsp70 5'-UTR containing only the cap-proximal and AUG-proximal segments. Linker-scanner mutations in the cap-proximal segment (+1 to +37) did not impair translation. Re-ordering the segments reduced mRNA translational efficiency by 50%. Deleting the AUG-proximal segment severely inhibited translation. A 5-extension of the full-length leader specifically impaired heat shock translation. These results indicate that heat shock reduces the capacity to unwind 5-UTR secondary structure, allowing only mRNAs with minimal 5'-UTR secondary structure to be efficiently translated. A function for specific sequences is also suggested. PMID:8710519

Interspecific- and acclimation-induced variation in levels of heat-shock proteins 70 (hsp70) and 90 (hsp90) and heat-shock transcription factor-1 (HSF1) in congeneric marine snails (genus Tegula): implications for regulation of hsp gene expression.

PubMed

Tomanek, Lars; Somero, George N

2002-03-01

In our previous studies of heat-shock protein (hsp) expression in congeneric marine gastropods of the genus Tegula, we observed interspecific and acclimation-induced variation in the temperatures at which heat-shock gene expression is induced (T(on)). To investigate the factors responsible for these inter- and intraspecific differences in T(on), we tested the predictions of the 'cellular thermometer' model for the transcriptional regulation of hsp expression. According to this model, hsps not active in chaperoning unfolded proteins bind to a transcription factor, heat-shock factor-1 (HSF1), thereby reducing the levels of free HSF1 that are available to bind to the heat-shock element, a regulatory element upstream of hsp genes. Under stress, hsps bind to denatured proteins, releasing HSF1, which can now activate hsp gene transcription. Thus, elevated levels of heat-shock proteins of the 40, 70 and 90 kDa families (hsp 40, hsp70 and hsp90, respectively) would be predicted to elevate T(on). Conversely, elevated levels of HSF1 would be predicted to decrease T(on). Following laboratory acclimation to 13, 18 and 23 degrees C, we used solid-phase immunochemistry (western analysis) to quantify endogenous levels of two hsp70 isoforms (hsp74 and hsp72), hsp90 and HSF1 in the low- to mid-intertidal species Tegula funebralis and in two subtidal to low-intertidal congeners, T. brunnea and T. montereyi. We found higher endogenous levels of hsp72 (a strongly heat-induced isoform) at 13 and 18 degrees C in T. funebralis in comparison with T. brunnea and T. montereyi. However, T. funebralis also had higher levels of HSF1 than its congeners. The higher levels of HSF1 in T. funebralis cannot, within the framework of the cellular thermometer model, account for the higher T(on) observed for this species, although they may explain why T. funebralis is able to induce the heat-shock response more rapidly than T. brunnea. However, the cellular thermometer model does appear to explain the

Low heat shock thresholds in wild Antarctic inter-tidal limpets (Nacella concinna)

PubMed Central

Geissler, Paul; Waller, Catherine; Fraser, Keiron P. P.; Barnes, David K. A.; Peck, Lloyd S.

2008-01-01

Heat shock proteins (HSPs) are a family of genes classically used to measure levels of organism stress. We have previously identified two HSP70 genes (HSP70A and HSP70B) in sub-tidal populations of the Antarctic limpet (Nacella concinna). These genes are up-regulated in response to increased seawater temperatures of 15°C or more during acute heat shock experiments, temperatures that have very little basis when considering the current Antarctic ecology of these animals. Therefore, the question was posed as to whether these animals could express HSP70 genes when subjected to more complex environmental conditions, such as those that occur in the inter-tidal. Inter-tidal limpets were collected on three occasions in different weather conditions at South Cove, Rothera Point, over a complete tidal cycle, and the expression levels of the HSP70 genes were measured. Both genes showed relative up-regulation of gene expression over the period of the tidal cycle. The average foot temperature of these animals was 3.3°C, far below that of the acute heat shock experiments. These experiments demonstrate that the temperature and expression levels of HSP production in wild animals cannot be accurately extrapolated from experimentally induced treatments, especially when considering the complexity of stressors in the natural environment. However, experimental manipulation can provide molecular markers for identifying stress in Antarctic molluscs, provided it is accompanied by environmental validation, as demonstrated here. Electronic supplementary material The online version of this article (doi:10.1007/s12192-008-0015-7) contains supplementary material, which is available to authorized users. PMID:18347941

The heat shock response plays an important role in TDP-43 clearance: evidence for dysfunction in amyotrophic lateral sclerosis.

PubMed

Chen, Han-Jou; Mitchell, Jacqueline C; Novoselov, Sergey; Miller, Jack; Nishimura, Agnes L; Scotter, Emma L; Vance, Caroline A; Cheetham, Michael E; Shaw, Christopher E

2016-05-01

Detergent-resistant, ubiquitinated and hyperphosphorylated Tar DNA binding protein 43 (TDP-43, encoded by TARDBP) neuronal cytoplasmic inclusions are the pathological hallmark in ∼95% of amyotrophic lateral sclerosis and ∼60% of frontotemporal lobar degeneration cases. We sought to explore the role for the heat shock response in the clearance of insoluble TDP-43 in a cellular model of disease and to validate our findings in transgenic mice and human amyotrophic lateral sclerosis tissues. The heat shock response is a stress-responsive protective mechanism regulated by the transcription factor heat shock factor 1 (HSF1), which increases the expression of chaperones that refold damaged misfolded proteins or facilitate their degradation. Here we show that manipulation of the heat shock response by expression of dominant active HSF1 results in a dramatic reduction of insoluble and hyperphosphorylated TDP-43 that enhances cell survival, whereas expression of dominant negative HSF1 leads to enhanced TDP-43 aggregation and hyperphosphorylation. To determine which chaperones were mediating TDP-43 clearance we over-expressed a range of heat shock proteins (HSPs) and identified DNAJB2a (encoded by DNAJB2, and also known as HSJ1a) as a potent anti-aggregation chaperone for TDP-43. DNAJB2a has a J domain, allowing it to interact with HSP70, and ubiquitin interacting motifs, which enable it to engage the degradation of its client proteins. Using functionally deleted DNAJB2a constructs we demonstrated that TDP-43 clearance was J domain-dependent and was not affected by ubiquitin interacting motif deletion or proteasome inhibition. This indicates that TDP-43 is maintained in a soluble state by DNAJB2a, leaving the total levels of TDP-43 unchanged. Additionally, we have demonstrated that the levels of HSF1 and heat shock proteins are significantly reduced in affected neuronal tissues from a TDP-43 transgenic mouse model of amyotrophic lateral sclerosis and patients with

Heat shock represses rRNA synthesis by inactivation of TIF-IA and lncRNA-dependent changes in nucleosome positioning.

PubMed

Zhao, Zhongliang; Dammert, Marcel A; Hoppe, Sven; Bierhoff, Holger; Grummt, Ingrid

2016-09-30

Attenuation of ribosome biogenesis in suboptimal growth environments is crucial for cellular homeostasis and genetic integrity. Here, we show that shutdown of rRNA synthesis in response to elevated temperature is brought about by mechanisms that target both the RNA polymerase I (Pol I) transcription machinery and the epigenetic signature of the rDNA promoter. Upon heat shock, the basal transcription factor TIF-IA is inactivated by inhibition of CK2-dependent phosphorylations at Ser170/172. Attenuation of pre-rRNA synthesis in response to heat stress is accompanied by upregulation of PAPAS, a long non-coding RNA (lncRNA) that is transcribed in antisense orientation to pre-rRNA. PAPAS interacts with CHD4, the adenosine triphosphatase subunit of NuRD, leading to deacetylation of histones and movement of the promoter-bound nucleosome into a position that is refractory to transcription initiation. The results exemplify how stress-induced inactivation of TIF-IA and lncRNA-dependent changes of chromatin structure ensure repression of rRNA synthesis in response to thermo-stress. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Heat Shock Protein 90 Inhibitor Decreases Collagen Synthesis of Keloid Fibroblasts and Attenuates the Extracellular Matrix on the Keloid Spheroid Model.

PubMed

Lee, Won Jai; Lee, Ju Hee; Ahn, Hyo Min; Song, Seung Yong; Kim, Yong Oock; Lew, Dae Hyun; Yun, Chae-Ok

2015-09-01

The 90-kDa heat-shock protein (heat-shock protein 90) is an abundant cytosolic chaperone, and inhibition of heat-shock protein 90 by 17-allylamino-17-demethoxygeldanamycin (17-AAG) compromises transforming growth factor (TGF)-β-mediated transcriptional responses by enhancing TGF-β receptor I and II degradation, thus preventing Smad2/3 activation. In this study, the authors evaluated whether heat-shock protein 90 regulates TGF-β signaling in the pathogenesis and treatment of keloids. Keloid fibroblasts were treated with 17-AAG (10 μM), and mRNA levels of collagen types I and III were determined by real-time reverse- transcriptase polymerase chain reaction. Also, secreted TGF-β1 was assessed by enzyme-linked immunosorbent assay. The effect of 17-AAG on protein levels of Smad2/3 complex was determined by Western blot analysis. In addition, in 17-AAG-treated keloid spheroids, the collagen deposition and expression of major extracellular matrix proteins were investigated by means of Masson trichrome staining and immunohistochemistry. The authors found that heat-shock protein 90 is overexpressed in human keloid tissue compared with adjacent normal tissue, and 17-AAG decreased mRNA levels of type I collagen, secreted TGF-ß1, and Smad2/3 complex protein expression in keloid fibroblasts. Masson trichrome staining revealed that collagen deposition was decreased in 17-AAG-treated keloid spheroids, and immunohistochemical analysis showed that expression of collagen types I and III, elastin, and fibronectin was markedly decreased in 17-AAG-treated keloid spheroids. These results suggest that the antifibrotic action of heat-shock protein 90 inhibitors such as 17-AAG may have therapeutic effects on keloids.

Experimental Investigation of Shock-Shock Interactions Over a 2-D Wedge at M=6

NASA Technical Reports Server (NTRS)

Jones, Michelle L.

2013-01-01

The effects of fin-leading-edge radius and sweep angle on peak heating rates due to shock-shock interactions were investigated in the NASA Langley Research Center 20-inch Mach 6 Air Tunnel. The fin model leading edges, which represent cylindrical leading edges or struts on hypersonic vehicles, were varied from 0.25 inches to 0.75 inches in radius. A 9deg wedge generated a planar oblique shock at 16.7deg to the flow that intersected the fin bow shock, producing a shock-shock interaction that impinged on the fin leading edge. The fin angle of attack was varied from 0deg (normal to the free-stream) to 15deg and 25deg swept forward. Global temperature data was obtained from the surface of the fused silica fins through phosphor thermography. Metal oil flow models with the same geometries as the fused silica models were used to visualize the streamline patterns for each angle of attack. High-speed zoom-schlieren videos were recorded to show the features and temporal unsteadiness of the shock-shock interactions. The temperature data were analyzed using one-dimensional semi-infinite as well as one- and two-dimensional finite-volume methods to determine the proper heat transfer analysis approach to minimize errors from lateral heat conduction due to the presence of strong surface temperature gradients induced by the shock interactions. The general trends in the leading-edge heat transfer behavior were similar for the three shock-shock interactions, respectively, between the test articles with varying leading-edge radius. The dimensional peak heat transfer coefficient augmentation increased with decreasing leading-edge radius. The dimensional peak heat transfer output from the two-dimensional code was about 20% higher than the value from a standard, semi-infinite one-dimensional method.

Transcriptional activity and DNA binding of heat shock factor-1 involve phosphorylation on threonine 142 by CK2.

PubMed

Soncin, Fabrice; Zhang, Xinfeng; Chu, Boyang; Wang, Xiaozhe; Asea, Alexzander; Ann Stevenson, Mary; Sacks, David B; Calderwood, Stuart K

2003-04-04

Heat shock factor-1 (HSF-1) is the regulator of hsp molecular chaperone transcription, although the intracellular mechanisms involved in HSF-1 activation have not been fully elucidated. As HSF1 is activated by heat shock simultaneously with the nuclear translocation of the protein kinase CK2, we have investigated the role of CK2 in HSF1 activation. We demonstrate that HSF-1 is phosphorylated by CK2 on both serine and threonine residues and has characterized a phosphorylation site at threonine 142. Mutation of Thr-142 to alanine (T142A) inhibits trans-activation of the HSP70 gene by HSF1 and in addition inhibits the accumulation of HSF-1 competent to bind heat shock elements in the nucleus. HSF1 activation by heat is correlated with the thermal activation of nuclear CK2 and overexpression of CK2 activates HSF1. Phosphorylation by CK2 on threonine 142 may therefore be an essential step in the thermal activation of latent HSF1 by stresses.

Shock wave as a probe of flux-dimited thermal transport in laser-heated solids

NASA Astrophysics Data System (ADS)

Smith, K.; Forsman, A.; Chiu, G.

1996-11-01

Laser-generated shock waves in solids result from the ablation of the target material. Where radiation transport is negligible, the ablation process is dominated by electron thermal conduction. This offers an opportunity to probe the degree of transport inhibition (compared with classical heat flow) for steep temperature gradients in a dense plasma. Using a 1-dimensional hydrodynamic code, we have examined the effect of flux-limited thermal conduction on the amplitude of the resulting shock wave.

The expression and function of hsp30-like small heat shock protein genes in amphibians, birds, fish, and reptiles.

PubMed

Heikkila, John J

2017-01-01

Small heat shock proteins (sHSPs) are a superfamily of molecular chaperones with important roles in protein homeostasis and other cellular functions. Amphibians, reptiles, fish and birds have a shsp gene called hsp30, which was also referred to as hspb11 or hsp25 in some fish and bird species. Hsp30 genes, which are not found in mammals, are transcribed in response to heat shock or other stresses by means of the heat shock factor that is activated in response to an accumulation of unfolded protein. Amino acid sequence analysis revealed that representative HSP30s from different classes of non-mammalian vertebrates were distinct from other sHSPs including HSPB1/HSP27. Studies with amphibian and fish recombinant HSP30 determined that they were molecular chaperones since they inhibited heat- or chemically-induced aggregation of unfolded protein. During non-mammalian vertebrate development, hsp30 genes were differentially expressed in selected tissues. Also, heat shock-induced stage-specific expression of hsp30 genes in frog embryos was regulated at the level of chromatin structure. In adults and/or tissue culture cells, hsp30 gene expression was induced by heat shock, arsenite, cadmium or proteasomal inhibitors, all of which enhanced the production of unfolded/damaged protein. Finally, immunocytochemical analysis of frog and chicken tissue culture cells revealed that proteotoxic stress-induced HSP30 accumulation co-localized with aggresome-like inclusion bodies. The congregation of damaged protein in aggresomes minimizes the toxic effect of aggregated protein dispersed throughout the cell. The current availability of probes to detect the presence of hsp30 mRNA or encoded protein has resulted in the increased use of hsp30 gene expression as a marker of proteotoxic stress in non-mammalian vertebrates. Copyright © 2016 Elsevier Inc. All rights reserved.

Heat Shock Proteins Are Important Mediators of Skeletal Muscle Insulin Sensitivity

PubMed Central

Geiger, Paige C.; Gupte, Anisha A.

2013-01-01

Endogenous heat shock proteins (HSP) are decreased in disease states associated with insulin resistance and aging. Induction of HSPs has been shown to decrease oxidative stress, inhibit inflammatory pathways, and enhance metabolic characteristics in skeletal muscle. As such, HSPs have the potential to function as an important defense system against the development of insulin resistance and type 2 diabetes. PMID:21088604

Prostaglandin E synthase interacts with inducible heat shock protein 70 after heat stress in bovine primary dermal fibroblast cells.

PubMed

Richter, Constanze; Viergutz, Torsten; Schwerin, Manfred; Weitzel, Joachim M

2015-01-01

Exposure to heat stress in dairy cows leads to undesired side effects that are reflected by complex alterations in endocrine parameters, such as reduced progesterone, estradiol, and thyroid hormone concentrations. These endocrine maladaptation leads to failure to resume cyclicity, a poor uterine environment and inappropriate immune responses in postpartum dairy cows. Prostaglandins (PG's) are lipid mediators, which serve as signal molecules in response to various external stimuli as well as to cell-specific internal signal molecules. A central role in PG synthesis plays prostaglandin E synthase (PGES) that catalyzes the isomerization of PGH2 to PGE2 .The present study was conducted to investigate heat stress associated PGES expression. Expression of PGES and inducible heat shock protein 70 (HSP70), as a putative chaperonic protein, was studied in bovine primary fibroblasts under different heat shock conditions. Bovine primary fibroblasts produce PGE2 at homoiothermical norm temperature (38.5°C in bovine), but reduce PGE2 production rates under extreme heat stress (at 45°C for 6 h). By contrast, PGE2 production rates are maintained after a milder heat stress (at 41.5°C for 6 h). PGE2 synthesis is abolished by application of cyclooxygenase inhibitor indomethacin, indicating de novo synthesis. Heat stress increases HSP70 but not PGES protein concentrations. HSP70 physically interacts with PGES and the PGES-HSP70 complex did not dissociate upon heat stress at 45°C even after returning the cells to 37°C. The PGE2 production negatively correlates with the portion of PGES-HSP70 complex. These results suggest a protein interaction between HSP70 and PGES in dermal fibroblast cells. Blockage of PGES protein by HSP70 seems to interfere with the regulatory processes essential for cellular adaptive protection. © 2014 International Society for Advancement of Cytometry. © 2014 International Society for Advancement of Cytometry.

The relationship between protein synthesis and heat shock proteins levels in rabbit reticulocyte lysates.

PubMed

Matts, R L; Hurst, R

1992-09-05

Besides heme deficiency, protein synthesis in rabbit reticulocyte lysates becomes inhibited upon exposure to a variety of agents that mimic conditions which induce the heat shock response in cells. This inhibition has been demonstrated to be due primarily to the activation of the heme-regulated eIF-2 alpha kinase (HRI) which causes an arrest in the initiation of translation. In this report, the sensitivity of protein synthesis in hemin-supplemented lysates to inhibition by Hg2+, GSSG, methylene blue, and heat shock was examined in six different reticulocyte lysate preparations. The extent to which translation was inhibited in response to Hg2+, GSSG, methylene blue, and heat shock correlated inversely with the relative levels of the 70-kDa heat shock proteins (hsp 70) and a 56-kDa protein (p56) present in the lysates determined by Western blotting. The ability of hemin to restore protein synthesis upon addition to heme-deficient lysates was also examined. While the restoration of protein synthesis correlated roughly with the levels of hsp 90 present, the results also suggest that the heme regulation of HRI probably involves the interaction of HRI with several factors present in the lysate besides hsp 90. A comparison of two lysate preparations, which had a 2-fold difference in their protein synthesis rates, indicated that the slower translational rate of the one lysate could be accounted for by its low level of constitutive eIF-2 alpha phosphorylation, with its accompanying decrease in the eIF-2B activity and lower level of polyribosome loading. The present study supports the notion that the previously demonstrated interaction of HRI with hsp 90, hsp 70, and p56 in reticulocyte lysates may play a direct role in regulating HRI activation or activity. We hypothesize that the competition of denatured protein and HRI for the binding of hsp 70 may be a molecular signal that triggers the activation of HRI in reticulocyte lysates in response to stress. Possible functions

Detection of the host immune response to Burkholderia mallei heat-shock proteins GroEL and DnaK in a glanders patient and infected mice.

PubMed

Amemiya, Kei; Meyers, Jennifer L; Deshazer, David; Riggins, Renaldo N; Halasohoris, Stephanie; England, Marilyn; Ribot, Wilson; Norris, Sarah L; Waag, David M

2007-10-01

We examined, by enzyme-linked immunosorbent assay and Western blot analysis, the host immune response to 2 heat-shock proteins (hsps) in a patient and mice previously infected with Burkholderia mallei. The patient was the first reported human glanders case in 50 years in the United States. The expression of the groEL and dnaK operons appeared to be dependent upon a sigma(32) RNA polymerase as suggested by conserved heat-shock promoter sequences, and the groESL operon may be negatively regulated by a controlling invert repeat of chaperone expression (CIRCE) site. In the antisera, the GroEL protein was found to be more immunoreactive than the DnaK protein in both a human patient and mice previously infected with B. mallei. Examination of the supernatant of a growing culture of B. mallei showed that more GroEL protein than DnaK protein was released from the cell. This may occur similarly within an infected host causing an elevated host immune response to the B. mallei hsps.

Production of the small heat shock protein Lo18 from Oenococcus oeni in Lactococcus lactis improves its stress tolerance.

PubMed

Weidmann, Stéphanie; Maitre, Magali; Laurent, Julie; Coucheney, Françoise; Rieu, Aurélie; Guzzo, Jean

2017-04-17

Lactococcus lactis is a lactic acid bacterium widely used in cheese and fermented milk production. During fermentation, L. lactis is subjected to acid stress that impairs its growth. The small heat shock protein (sHsp) Lo18 from the acidophilic species Oenococcus oeni was expressed in L. lactis. This sHsp is known to play an important role in protein protection and membrane stabilization in O. oeni. The role of this sHsp could be studied in L. lactis, since no gene encoding for sHsp has been detected in this species. L. lactis subsp. cremoris strain MG1363 was transformed with the pDLhsp18 plasmid, which is derived from pDL278 and contains the hsp18 gene (encoding Lo18) and its own promoter sequence. The production of Lo18 during stress conditions was checked by immunoblotting and the cellular distribution of Lo18 in L. lactis cells after heat shock was determined. Our results clearly indicated a role for Lo18 in cytoplasmic protein protection and membrane stabilization during stress. The production of sHsp in L. lactis improved tolerance to heat and acid conditions in this species. Finally, the improvement of the L. lactis survival in milk medium thanks to Lo18 was highlighted, suggesting an interesting role of this sHsp. These findings suggest that the expression of a sHsp by a L. lactis strain results in greater resistance to stress, and, can consequently enhance the performances of industrial strains. Copyright © 2016 Elsevier B.V. All rights reserved.

Cancer-linked satellite 2 DNA hypomethylation does not regulate Sat2 non-coding RNA expression and is initiated by heat shock pathway activation.

PubMed

Tilman, Gaëlle; Arnoult, Nausica; Lenglez, Sandrine; Van Beneden, Amandine; Loriot, Axelle; De Smet, Charles; Decottignies, Anabelle

2012-08-01