Heat shock-induced attenuation of hydroxyl radical generation and mitochondrial aconitase activity in cardiac H9c2 cells

A mild heat shock (hyperthermia) protects cells from apoptotic and necrotic deaths by inducing overexpression of various heat shock proteins (Hsps). These proteins, in combination with the activation of the nitric oxide synthase (NOS) enzyme, play important roles in the protection of the myocardium against a variety of diseases. In the present work we report that the generation of potent reactive oxygen species (ROS), namely ·OH in cardiac H9c2 cells, is attenuated by heat shock treatment (2 h at 42°C). Western blot analyses showed that heat shock treatment induced overexpression of Hsp70, Hsp60, and Hsp25. The observed ·OH was found to be derived from the superoxide (O2−·) generated by the mitochondria. Whereas the manganese superoxide dismutase (MnSOD) activity was increased in the heat-shocked cells, the mitochondrial aconitase activity was reduced. The mechanism of O2−· conversion into ·OH in mitochondria is proposed as follows. The O2−· leaked from the electron transport chain, oxidatively damages the mitochondrial aconitase, releasing a free Fe2+. The aconitase-released Fe2+ combines with H2O2 to generate ·OH via a Fenton reaction and the oxidized Fe3+ recombines with the inactivated enzyme after being reduced to Fe2+ by other cellular reductants, turning it over to be active. However, in heat-shocked cells, because of higher MnSOD activity, the excess H2O2 causes irreversible damage to the mitochondrial aconitase enzyme, thus inhibiting its activity. In conclusion, we propose that attenuation of ·OH generation after heat shock treatment might play an important role in reducing the myocardial ischemic injury, observed in heat shock-treated animals.

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Heat-shock proteins in monitoring aging and heat-induced tolerance in germinating wheat and barley embryos

Seed Science Research ◽

10.1017/s0960258500003986 ◽

1998 ◽

Vol 8 (2) ◽

pp. 91-98 ◽

Cited By ~ 9

Author(s):

A. Dell'Aquila ◽

M. G. Corona ◽

M. Di Turi

Keyword(s):

Heat Shock ◽

Accelerated Aging ◽

Shock Treatment ◽

Heat Shock Treatment ◽

General Decline ◽

Aging Conditions ◽

Germination Behaviour ◽

Induced Tolerance ◽

Shock Proteins ◽

Aged Seeds

AbstractWheat and barley seeds were subjected to accelerated aging conditions at 12% moisture content and 35°C temperature over 28 days of storage, and to heat-shock treatment carried out by 4 h of incubation at 40°C following 16 h of imbibition at 20°C. Heat-treated, aged seeds showed altered germination behaviour and increasing leakage electroconductivity as well as a reduced incorporation of [35S]-methionine into embryo proteins, in comparison with the corresponding untreated seeds. Two-dimensional electrophoresis of labelled proteins from embryos gave evidence of further quantitative and qualitative changes: (a) ‘normal’ germination protein synthesis in wheat and barley was slightly modified by age, but following heat-shock treatment a general reduction of most of the control polypeptides occurred; (b) heat-shock response resulted in the production of several HSPs with different MW and pl, but a uniform general decline in their synthesis was not observed. Highly labelled HSPs (e.g., those with MW 66.7 or 89.3–66.7 kDa in wheat or barley, respectively) did not change over the entire period of aging, while some smaller HSPs with MW >29 kDa either decreased in intensity or disappeared. Conversely, specific low molecular weight HSPs (MW 17–14.2 kDa) were synthesized more in extremely aged embryos of both species. The hypothesis that these polypeptides may be used as biochemical markers in monitoring both vigour loss and heat-shock induced tolerance in aged seeds is discussed.

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Heat-induced triploids in Brycon amazonicus: a strategic fish species for aquaculture and conservation

Zygote ◽

10.1017/s0967199421000125 ◽

2021 ◽

pp. 1-5

Author(s):

Nivaldo Ferreira do Nascimento ◽

Rafaela Manchin Bertolini ◽

Lucia Soares Lopez ◽

Laura Satiko Okada Nakaghi ◽

Paulo Sérgio Monzani ◽

...

Keyword(s):

Flow Cytometry ◽

Heat Shock ◽

Early Development ◽

Fish Species ◽

Survival Rates ◽

Shock Treatment ◽

Hatching Rate ◽

Heat Shock Treatment ◽

Control Survival ◽

Ploidy Status

Summary Triploidization plays an important role in aquaculture and surrogate technologies. In this study, we induced triploidy in the matrinxã fish (Brycon amazonicus) using a heat-shock technique. Embryos at 2 min post fertilization (mpf) were heat shocked at 38°C, 40°C, or 42°C for 2 min. Untreated, intact embryos were used as a control. Survival rates during early development were monitored and ploidy status was confirmed using flow cytometry and nuclear diameter analysis of erythrocytes. The hatching rate reduced with heat-shock treatment, and heat-shock treatments at 42°C resulted in no hatching events. Optimal results were obtained at 40°C with 95% of larvae exhibiting triploidy. Therefore, we report that heat-shock treatments of embryos (2 mpf) at 40°C for 2 min is an effective way to induce triploid individuals in B. amazonicus.

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Characterization of the thermotolerant cell. I. Effects on protein synthesis activity and the regulation of heat-shock protein 70 expression.

The Journal of Cell Biology ◽

10.1083/jcb.106.4.1105 ◽

1988 ◽

Vol 106 (4) ◽

pp. 1105-1116 ◽

Cited By ~ 264

Author(s):

L A Mizzen ◽

W J Welch

Keyword(s):

Protein Synthesis ◽

Heat Shock ◽

Stress Proteins ◽

Stress Protein ◽

Shock Treatment ◽

Heat Shock Treatment ◽

Normal Medium ◽

Growth Environment ◽

Mammalian Cell Lines ◽

C 30

Exposure of mammalian cells to a nonlethal heat-shock treatment, followed by a recovery period at 37 degrees C, results in increased cell survival after a subsequent and otherwise lethal heat-shock treatment. Here we characterize this phenomenon, termed acquired thermotolerance, at the level of translation. In a number of different mammalian cell lines given a severe 45 degrees C/30-min shock and then returned to 37 degrees C, protein synthesis was completely inhibited for as long as 5 h. Upon resumption of translational activity, there was a marked induction of heat-shock (or stress) protein synthesis, which continued for several hours. In contrast, cells first made thermotolerant (by a pretreatment consisting of a 43 degrees C/1.5-h shock and further recovery at 37 degrees C) and then presented with the 45 degrees C/30-min shock exhibited considerably less translational inhibition and an overall reduction in the amount of subsequent stress protein synthesis. The acquisition and duration of such "translational tolerance" was correlated with the expression, accumulation, and relative half-lives of the major stress proteins of 72 and 73 kD. Other agents that induce the synthesis of the stress proteins, such as sodium arsenite, similarly resulted in the acquisition of translational tolerance. The probable role of the stress proteins in the acquisition of translational tolerance was further indicated by the inability of the amino acid analogue, L-azetidine 2-carboxylic acid, an inducer of nonfunctional stress proteins, to render cells translationally tolerant. If, however, analogue-treated cells were allowed to recover in normal medium, and hence produce functional stress proteins, full translational tolerance was observed. Finally, we present data indicating that the 72- and 73-kD stress proteins, in contrast to the other major stress proteins (of 110, 90, and 28 kD), are subject to strict regulation in the stressed cell. Quantitation of 72- and 73-kD synthesis after heat-shock treatment under a number of conditions revealed that "titration" of 72/73-kD synthesis in response to stress may represent a mechanism by which the cell monitors its local growth environment.

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DNA damage and heat shock dually regulate genes in Saccharomyces cerevisiae.

Molecular and Cellular Biology ◽

10.1128/mcb.6.1.90 ◽

1986 ◽

Vol 6 (1) ◽

pp. 90-96 ◽

Cited By ~ 39

Author(s):

T McClanahan ◽

K McEntee

Keyword(s):

Saccharomyces Cerevisiae ◽

Dna Damage ◽

Heat Shock ◽

Shock Treatment ◽

Northern Hybridization ◽

Heat Shock Treatment ◽

Base Pairs ◽

S1 Nuclease ◽

Hsp70 Family ◽

Transcriptional Start Sites

Two Saccharomyces cerevisiae genes isolated in a differential hybridization screening for DNA damage regulation (DDR genes) were also transcriptionally regulated by heat shock treatment. A 0.45-kilobase transcript homologous to the DDRA2 gene and a 1.25-kilobase transcript homologous to the DDR48 gene accumulated after exposure of cells to 4-nitroquinoline-1-oxide (NQO; 1 to 1.5 microgram/ml) or brief heat shock (20 min at 37 degrees C). The DDRA2 transcript, which was undetectable in untreated cells, was induced to high levels by these treatments, and the DDR48 transcript increased more than 10-fold as demonstrated by Northern hybridization analysis. Two findings argue that dual regulation of stress-responsive genes is not common in S. cerevisiae. First, two members of the heat shock-inducible hsp70 family of S. cerevisiae, YG100 and YG102, were not induced by exposure to NQO. Second, at least one other DNA-damage-inducible gene, DIN1, was not regulated by heat shock treatment. We examined the structure of the induced RNA homologous to DDRA2 after heat shock and NQO treatments by S1 nuclease protection experiments. Our results demonstrated that the DDRA2 transcript initiates equally frequently at two sites separated by 5 base pairs. Both transcriptional start sites were utilized when cells were exposed to either NQO or heat shock treatment. These results indicate that DDRA2 and DDR48 are members of a unique dually regulated stress-responsive family of genes in S. cerevisiae.

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Repetitive Dictyostelium heat-shock promotor functions in Saccharomyces cerevisiae

Molecular and Cellular Biology ◽

10.1128/mcb.4.4.591-598.1984 ◽

1984 ◽

Vol 4 (4) ◽

pp. 591-598

Author(s):

J Cappello ◽

C Zuker ◽

H F Lodish

Keyword(s):

Saccharomyces Cerevisiae ◽

Heat Shock ◽

Nucleotide Sequence ◽

Dna Sequence ◽

Base Pair ◽

Shock Treatment ◽

Yeast Cells ◽

Genomic Segment ◽

Heat Shock Treatment ◽

Shock Response

The Dictyostelium genome contains 40 copies of a 4.7-kilobase repetitive and apparently transposable DNA sequence (DIRS-1) and about 250 smaller elements that appear to be deletions or rearrangements of DIRS-1. Transcripts of these sequences are induced during differentiation and also by heat shock treatment of growing cells. We showed that one such cloned element, pB41.6 (2.5 kilobases) contains a nucleotide sequence identical to the Drosophila consensus heat shock promotor. To test whether this sequence might indeed control the expression of DIRS-1-related RNAs, we have cloned this genomic segment into yeast cells. In yeast cells, 41.6 directs synthesis of a 1.7-kilobase RNA that is induced at least 10-fold by heat shock. Transcription initiates at about 124 bases 3' of the putative promotor sequence and terminates within the 41.6 insert. A 381-base-pair subclone that contains the putative promotor sequence is sufficient to induce the heat shock response of 41.6 in yeast cells.

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Heat Shock Treatment Enhances Graft Cell Survival in Skeletal Myoblast Transplantation to the Heart

Circulation ◽

10.1161/circ.102.suppl_3.iii-216 ◽

2000 ◽

Vol 102 (suppl_3) ◽

Cited By ~ 2

Author(s):

Ken Suzuki ◽

Ryszard T. Smolenski ◽

Jay Jayakumar ◽

Bari Murtuza ◽

Nigel J. Brand ◽

...

Keyword(s):

Heat Shock ◽

Cell Survival ◽

Cell Transplantation ◽

Shock Treatment ◽

Heat Shock Treatment ◽

Skeletal Myoblast ◽

Skeletal Myoblasts ◽

Myoblast Transplantation ◽

Hypoxia Reoxygenation

Background —Graft survival after skeletal myoblast transplantation is affected by various pathological processes caused by environmental stress. Heat shock is known to afford protection of several aspects of cell metabolism and function. We hypothesized that prior heat shock treatment of graft cells would improve their survival after cell transplantation. Methods and Results —L6 rat skeletal myoblasts expressing β-galactosidase (β-gal) were subjected to heat shock (42°C, 1 hour). Increased expression of heat shock protein 72 was detected 24 hours later in the heat-shocked cells. After hypoxia-reoxygenation in vitro, lactate dehydrogenase leakage was significantly attenuated in the heat-shocked cells; in addition, the percentage of early apoptosis was lower in this group measured by flow cytometry with annexin V staining. For the in vivo study, 1×10 6 heat-shocked (hsCTx) or normal-cultured (CTx) myoblasts were infused into the explanted rat hearts through the coronary artery followed by heterotopic heart transplantation. β-gal activity was significantly higher in the hsCTx group after cell transplantation, with an estimated 8×10 6 surviving cells per heart in the hsCTx group and 5×10 6 cells in the CTx group on day 28. Discrete loci of grafted cells were globally observed in the myocardium of the hsCTx and CTx groups, with a higher frequency in the hsCTx group. Surviving myoblasts occasionally differentiated into myotubes and had integrated with the native cardiomyocytes. Conclusions —Heat-shocked skeletal myoblasts demonstrated improved tolerance to hypoxia-reoxygenation insult in vitro and enhanced survival when grafted into the heart. Heat shock treatment could be useful in improving graft cell survival in cell transplantation.

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Short-term exercise training can improve myocardial tolerance to I/R without elevation in heat shock proteins

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2001.281.3.h1346 ◽

2001 ◽

Vol 281 (3) ◽

pp. H1346-H1352 ◽

Cited By ~ 105

Author(s):

Karyn L. Hamilton ◽

Scott K. Powers ◽

Takao Sugiura ◽

Sunjoo Kim ◽

Shannon Lennon ◽

...

Keyword(s):

Lipid Peroxidation ◽

Heat Shock ◽

Heat Shock Proteins ◽

Ischemia Reperfusion ◽

Left Ventricular ◽

Antioxidant Defenses ◽

Control Group ◽

Shock Proteins ◽

Mnsod Activity ◽

Over Time

We examined the effects of 3 days of exercise in a cold environment on the expression of left ventricular (LV) heat shock proteins (HSPs) and contractile performance during in vivo ischemia-reperfusion (I/R). Sprague-Dawley rats were divided into the following three groups ( n = 12/group): 1) control, 2) exercise (60 min/day) at 4°C (E-Cold), and 3) exercise (60 min/day) at 25°C (E-Warm). Left anterior descending coronary occlusion was maintained for 20 min, followed by 30 min of reperfusion. Compared with the control group, both the E-Cold and E-Warm groups maintained higher ( P < 0.05) LV developed pressure, first derivative of pressure development over time (+dP/d t), and pressure relaxation over time (−dP/d t) throughout I/R. Relative levels of HSP90, HSP72, and HSP40 were higher ( P < 0.05) in E-Warm animals compared with both control and E-Cold. HSP10, HSP60, and HSP73 did not differ between groups. Exercise increased manganese superoxide dismutase (MnSOD) activity in both E-Warm and E-Cold hearts ( P < 0.05). Protection against I/R-induced lipid peroxidation in the LV paralleled the increase in MnSOD activity whereas lower levels of lipid peroxidation were observed in both E-Warm and E-Cold groups compared with control. We conclude that exercise-induced myocardial protection against a moderate duration I/R insult is not dependent on increases in myocardial HSPs. We postulate that exercise-associated cardioprotection may depend, in part, on increases in myocardial antioxidant defenses.

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