scholarly journals Regulation of heat shock protein synthesis by quercetin in human erythroleukaemia cells

1994 ◽  
Vol 300 (1) ◽  
pp. 201-209 ◽  
Author(s):  
G Elia ◽  
M G Santoro
Keyword(s):  
Heat Shock ◽  
Mammalian Cells ◽  
Elevated Temperatures ◽  
K562 Cells ◽  
Hsp70 Expression ◽  
Transcriptional Level ◽  
Hsp70 Mrna ◽  
Shock Proteins ◽  
Hsp70 Synthesis

Synthesis of heat-shock proteins (HSPs) is universally induced in eukaryotic and prokaryotic cells by exposure to elevated temperatures or to other types of environmental stress. In mammalian cells, HSPs belonging to the 70 kDa family (HSP70) have a regulatory role in several cellular processes, and have been shown to be involved in the control of cell proliferation and differentiation. Although many types of HSP70 inducers have been identified, only a few compounds, all belonging to the flavonoid group, have been shown to inhibit HSP70 induction. Because inhibitors of HSP70 synthesis could be an important tool with which to study the function of this protein, we have investigated the effect of quercetin, a flavonoid with antiproliferative activity which is widely distributed in nature, on HSP70 synthesis in human K562 erythroleukaemia cells after treatment with severe or mild heat shock and with other inducers. Quercetin was found to affect HSP70 synthesis at more than one level, depending on the conditions used. Indeed, after severe heat shock (45 degrees C for 20 min) treatment with quercetin, at non-toxic concentrations, was found to inhibit HSP70 synthesis for a period of 3-4 h. This block appeared to be exerted at the post-transcriptional level and to be cell-mediated, as the addition of quercetin during translation of HSP70 mRNA in vitro had no effect. After prolonged (90 min) exposure at 43 degrees C, however, quercetin was found to inhibit also HSP70 mRNA transcription. Pretreatment of K562 cells with quercetin had no effect on HSP70 expression, and quercetin needed to be present during induction to be effective. Under all conditions tested, the quercetin-induced block of HSP70 synthesis was found to be transient and, after an initial delay, synthesis of HSP70 reached the control rate and continued at the same level for several hours after the time at which HSP70 synthesis had been turned off in control cells. Finally, inhibition of HSP70 synthesis by quercetin appeared to be dependent on the temperature used and on the type of stressor.

Preferential deadenylation of Hsp70 mRNA plays a key role in regulating Hsp70 expression in Drosophila melanogaster

1994 ◽  
Vol 14 (6) ◽  
pp. 3646-3659
Author(s):  
R P Dellavalle ◽  
R Petersen ◽  
S Lindquist
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Rna Processing ◽  
Hsp70 Expression ◽  
Hsp70 Mrna ◽  
Mild Heat ◽  
Endonucleolytic Cleavage ◽  
Heat Shocks ◽  
Low Efficiency ◽  
Hsp70 Synthesis

Following a standard heat shock, approximately 40% of Hsp70 transcripts in Drosophila melanogaster lack a poly(A) tail. Since heat shock disrupts other aspects of RNA processing, this observation suggested that heat might disrupt polyadenylation as well. We find, however, that as the temperature is increased a larger fraction of Hsp70 RNA is polyadenylated. Poly(A)-deficient Hsp70 RNAs arise not from a failure in polyadenylation but from the rapid and selective removal of poly(A) from previously adenylated transcripts. Poly(A) removal is highly regulated: poly(A) is (i) removed much more rapidly from Hsp70 RNAs than from Hsp23 RNAs, (ii) removed more rapidly after mild heat shocks than after severe heat shocks, and (iii) removed more rapidly after a severe heat shock if cells have first been conditioned by a mild heat treatment. Poly(A) seems to be removed by simple deadenylation rather than by endonucleolytic cleavage 5' of the adenylation site. During recovery from heat shock, deadenylation is rapidly followed by degradation. In cells maintained at high temperatures, however, the two processes are uncoupled and Hsp70 RNAs are deadenylated without being degraded. These deadenylated mRNAs are translated with low efficiency. Deadenylation therefore allows Hsp70 synthesis to be repressed even when degradation of the mRNA is blocked. Poly(A) tail shortening appears to play a key role in regulating Hsp70 expression.

scholarly journals Induction by prostaglandin A1 of haem oxygenase in myoblastic cells: an effect independent of expression of the 70 kDa heat shock protein

1995 ◽  
Vol 308 (2) ◽  
pp. 455-463 ◽  
Author(s):  
A Rossi ◽  
M G Santoro
Keyword(s):  
Heat Shock ◽  
Mammalian Cells ◽  
Present Report ◽  
Oxidant Stress ◽  
Stress Protein ◽  
Hsp70 Expression ◽  
Transcriptional Level ◽  
Protective Mechanisms ◽  
Haem Oxygenase ◽  
Prostaglandin A1

Prostaglandins of the A type (PGA) induce the synthesis of 70 kDa heat shock proteins (hsp70) in a large variety of mammalian cells. Induction of hsp70 has been associated with a cytoprotective effect of PGA1 after virus infection or thermal injury. In the present report we provide evidence that, in murine myoblasts, PGA1 is not able to induce hsp70 expression, whereas it increases the synthesis of the constitutive protein, hsc70, and dramatically induces the synthesis of a 32 kDa protein (p32). The p32 protein has been identified as haem oxygenase. PGA1 acts at the transcriptional level by inducing haem oxygenase mRNA synthesis, and the signal for induction appears to be associated with decreased intracellular GSH levels. Haem oxygenase, a low-molecular-mass stress protein induced in mammalian cells by oxidant stress, is known to be part of a general inducible antioxidant defence pathway. The fact that prostaglandin synthesis is stimulated in muscle during contraction and in the heart in response to ischaemia raises the possibility that induction of haem oxygenase by PGA in myoblasts could be part of a protective mechanisms in operation during stress and hypoxia.

Heat shock-induced translational control of HSP70 and globin synthesis in chicken reticulocytes

1984 ◽  
Vol 4 (11) ◽  
pp. 2437-2448
Author(s):  
S S Banerji ◽  
N G Theodorakis ◽  
R I Morimoto
Keyword(s):  
Heat Shock ◽  
Translational Control ◽  
Actinomycin D ◽  
Elevated Temperatures ◽  
Rapid Change ◽  
Hsp70 Gene ◽  
Globin Mrna ◽  
Hsp70 Mrna ◽  
Globin Synthesis

Incubation of chicken reticulocytes at elevated temperatures (43 to 45 degrees C) resulted in a rapid change in the pattern of protein synthesis, characterized by the decreased synthesis of normal proteins, e.g., alpha and beta globin, and the preferential and increased synthesis of only one heat shock protein, HSP70. The repression of globin synthesis was not due to modifications of globin mRNA because the level of globin mRNA and its ability to be translated in vitro were unaffected. The HSP70 gene in reticulocytes was transcribed in non-heat-shocked cells, yet HSP70 was not efficiently translated until the cells had been heat shocked. In non-heat-shocked reticulocytes, HSP70 mRNA was a moderately abundant mRNA present at 1 to 2% of the level of globin mRNA. The rapid 20-fold increase in the synthesis of HSP70 after heat shock was not accompanied by a corresponding increase in the rate of transcription of the HSP70 gene or accumulation of HSP70 mRNA. These results suggest that the elevated synthesis of HSP70 is due to the preferential utilization of HSP70 mRNA in the heat-shocked reticulocyte. The heat shock-induced alterations in the reticulocyte protein-synthetic apparatus were not reversible. Upon return to control temperatures (37 degrees C), heat-shocked reticulocytes continued to synthesize HSP70 at elevated levels whereas globin synthesis continued to be repressed. Despite the presence of HSP70 mRNA in non-heat-shocked reticulocytes, we found that continued transcription was necessary for the preferential translation of HSP70 in heat-shocked cells. Preincubation of reticulocytes with the transcription inhibitor actinomycin D or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole blocked the heat shock-induced synthesis of HSP70. Because the level of HSP70 mRNA was only slightly diminished in cells treated with actinomycin D, we suggest two possible mechanisms for the preferential translation of HSP70 mRNA: the translation of only newly transcribed HSP70 mRNA or the requirement of a newly transcribed RNA-containing factor.

Exercising mammals synthesize stress proteins

1990 ◽  
Vol 258 (4) ◽  
pp. C723-C729 ◽  
Author(s):  
M. Locke ◽  
E. G. Noble ◽  
B. G. Atkinson
Keyword(s):  
Heat Shock ◽  
Mammalian Cells ◽  
Stress Proteins ◽  
Sprague Dawley ◽  
Spleen Cells ◽  
Sprague Dawley Rats ◽  
Electrophoretic Separations ◽  
Shock Proteins ◽  
Sufficient Stimulus

Spleen cells, peripheral lymphocytes, and soleus muscles were removed from male Sprague-Dawley rats that had been run on a treadmill (24 m/min) for either 20, 40, or 60 min or to exhaustion (86 +/- 41 min) and were labeled in vitro with [35S]methionine at 37 degrees C. Similar tissues from nonrunning control rats were labeled in vitro at either 37 or 43 degrees C (heat shock). Fluorographic analyses of one- and two-dimensional polyacrylamide gel electrophoretic separations of the proteins from cells and tissues of exercised rats demonstrate the new or enhanced synthesis of proteins of approximately 65, 72, 90, and 100 kDa. Although synthesis of these proteins is low or not detectable in tissues from control rats labeled at 37 degrees C, they are prominent products of similar tissues labeled under heat-shock conditions (43 degrees C) and, in fact, correspond in Mr and pI with the so-called heat-shock proteins. These results suggest that exercise is a sufficient stimulus to induce or enhance the synthesis of heat shock and/or stress proteins in mammalian cells and tissues.

scholarly journals Heat shock response of Trichinella spiralis and T. pseudospiralis

Parasitology ◽  
1996 ◽  
Vol 112 (1) ◽  
pp. 89-95 ◽  
Author(s):  
R. C. Ko ◽  
L. Fan
Keyword(s):  
Heat Shock ◽  
Trichinella Spiralis ◽  
Transcriptional Level ◽  
Sds Page ◽  
Rabbit Reticulocyte Lysate System ◽  
Reticulocyte Lysate ◽  
Shock Proteins ◽  
First Time ◽  
Laser Densitometry

SUMMARYHeat shock proteins (HSPs) were documented for the first time in both somatic extracts and excretory/secretory (ES) products of the infective-stage larvae of Trichinella spiralis and T. pseudospiralis. Larvae recovered from muscles of infected mice were heat shocked at 37, 40, 43 and 45 °C in RPMI 1640 medium containing L-[35S]methionine. Somatic extracts and ES products of heat-shocked worms were then analysed by SDS-PAGE, autoradiography and laser densitometry. Prominent bands of HSPs were observed at 43 °C which is the optimal heat shock temperature. The major HSPs in somatic extracts of T. spiralis were 20, 47, 50, 70, 80 and 86 kDa. When the temperature was increased from 37 to 43 °C, the greatest increase in absorbance was observed in HSPs 70 and 86. In vitro translation of mRNA in a nuclease-treated rabbit reticulocyte lysate system showed an increase in the synthesis of the 80 kDa protein. This suggests that the production of HSP 80 is regulated at the transcriptional level. The major HSPs in the ES products were 11, 45, 53 and 64 kDa. In T. pseudospiralis, the major HSPs in the somatic extracts were 20, 26, 31, 50, 53, 70, 80 and 86 kDa, and in the ES products, 11, 35, 37, 41 and 64 kDa.

scholarly journals Preferential deadenylation of Hsp70 mRNA plays a key role in regulating Hsp70 expression in Drosophila melanogaster.

1994 ◽  
Vol 14 (6) ◽  
pp. 3646-3659 ◽  
Author(s):  
R P Dellavalle ◽  
R Petersen ◽  
S Lindquist
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Rna Processing ◽  
Hsp70 Expression ◽  
Hsp70 Mrna ◽  
Mild Heat ◽  
Endonucleolytic Cleavage ◽  
Heat Shocks ◽  
Low Efficiency ◽  
Hsp70 Synthesis

Following a standard heat shock, approximately 40% of Hsp70 transcripts in Drosophila melanogaster lack a poly(A) tail. Since heat shock disrupts other aspects of RNA processing, this observation suggested that heat might disrupt polyadenylation as well. We find, however, that as the temperature is increased a larger fraction of Hsp70 RNA is polyadenylated. Poly(A)-deficient Hsp70 RNAs arise not from a failure in polyadenylation but from the rapid and selective removal of poly(A) from previously adenylated transcripts. Poly(A) removal is highly regulated: poly(A) is (i) removed much more rapidly from Hsp70 RNAs than from Hsp23 RNAs, (ii) removed more rapidly after mild heat shocks than after severe heat shocks, and (iii) removed more rapidly after a severe heat shock if cells have first been conditioned by a mild heat treatment. Poly(A) seems to be removed by simple deadenylation rather than by endonucleolytic cleavage 5' of the adenylation site. During recovery from heat shock, deadenylation is rapidly followed by degradation. In cells maintained at high temperatures, however, the two processes are uncoupled and Hsp70 RNAs are deadenylated without being degraded. These deadenylated mRNAs are translated with low efficiency. Deadenylation therefore allows Hsp70 synthesis to be repressed even when degradation of the mRNA is blocked. Poly(A) tail shortening appears to play a key role in regulating Hsp70 expression.

scholarly journals Heat shock-induced translational control of HSP70 and globin synthesis in chicken reticulocytes.

1984 ◽  
Vol 4 (11) ◽  
pp. 2437-2448 ◽  
Author(s):  
S S Banerji ◽  
N G Theodorakis ◽  
R I Morimoto
Keyword(s):  
Heat Shock ◽  
Translational Control ◽  
Actinomycin D ◽  
Elevated Temperatures ◽  
Rapid Change ◽  
Hsp70 Gene ◽  
Globin Mrna ◽  
Hsp70 Mrna ◽  
Globin Synthesis

Incubation of chicken reticulocytes at elevated temperatures (43 to 45 degrees C) resulted in a rapid change in the pattern of protein synthesis, characterized by the decreased synthesis of normal proteins, e.g., alpha and beta globin, and the preferential and increased synthesis of only one heat shock protein, HSP70. The repression of globin synthesis was not due to modifications of globin mRNA because the level of globin mRNA and its ability to be translated in vitro were unaffected. The HSP70 gene in reticulocytes was transcribed in non-heat-shocked cells, yet HSP70 was not efficiently translated until the cells had been heat shocked. In non-heat-shocked reticulocytes, HSP70 mRNA was a moderately abundant mRNA present at 1 to 2% of the level of globin mRNA. The rapid 20-fold increase in the synthesis of HSP70 after heat shock was not accompanied by a corresponding increase in the rate of transcription of the HSP70 gene or accumulation of HSP70 mRNA. These results suggest that the elevated synthesis of HSP70 is due to the preferential utilization of HSP70 mRNA in the heat-shocked reticulocyte. The heat shock-induced alterations in the reticulocyte protein-synthetic apparatus were not reversible. Upon return to control temperatures (37 degrees C), heat-shocked reticulocytes continued to synthesize HSP70 at elevated levels whereas globin synthesis continued to be repressed. Despite the presence of HSP70 mRNA in non-heat-shocked reticulocytes, we found that continued transcription was necessary for the preferential translation of HSP70 in heat-shocked cells. Preincubation of reticulocytes with the transcription inhibitor actinomycin D or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole blocked the heat shock-induced synthesis of HSP70. Because the level of HSP70 mRNA was only slightly diminished in cells treated with actinomycin D, we suggest two possible mechanisms for the preferential translation of HSP70 mRNA: the translation of only newly transcribed HSP70 mRNA or the requirement of a newly transcribed RNA-containing factor.

scholarly journals Expression of heat shock protein 70 is altered by age and diet at the level of transcription

1993 ◽  
Vol 13 (5) ◽  
pp. 2909-2918
Author(s):  
A R Heydari ◽  
B Wu ◽  
R Takahashi ◽  
R Strong ◽  
A Richardson
Keyword(s):  
Heat Shock ◽  
Caloric Restriction ◽  
Hsp70 Expression ◽  
Mrna Levels ◽  
Age Related ◽  
Restriction Diet ◽  
Old Rats ◽  
Ad Libitum ◽  
Shock Proteins ◽  
Hsp70 Synthesis

Because heat shock proteins have been shown to play a critical role in protecting cells from hyperthermia and other types of physiological stresses, it was of interest to determine what effect age and caloric restriction have on the ability of cells to regulate the expression of heat shock protein 70 (hsp70), the most prominent and most evolutionarily conserved of the heat shock proteins. Caloric restriction is the only experimental manipulation known to retard aging and increase survival of mammals. The ability of hepatocytes isolated from young/adult (4- to 7-month-old) and old (22- to 28-month-old) male Fischer F344 rats fed ad libitum or a caloric restriction diet (60% of the content of the ad libitum diet) to express hsp70 was determined after a mild heat shock (42.5 degrees C for 30 min). We found that the induction of hsp70 synthesis and mRNA levels by heat shock was 40 to 50% lower in hepatocytes isolated from old rats than in hepatocytes isolated from young rats. Using in situ hybridization, we found that essentially all hepatocytes from the young/adult and old rats expressed hsp70 in response to heat shock; therefore, the age-related decrease in the induction of hsp70 expression was not due to an age-related accumulation of cells that do not respond to heat shock. Measurements of hsp70 mRNA stability and hsp70 transcription demonstrated that the age-related decline in hsp70 expression arose from a decline in hsp70 transcription. Interestingly, the age-related decline in the induction of hsp70 expression was reversed by caloric restriction; e.g., the induction of hsp70 synthesis, mRNA levels, and nuclear transcription were significantly higher in hepatocytes isolated from old rats fed the caloric restricted diet than in hepatocytes isolated from old rats fed ad libitum. The levels of the heat shock transcription factor in nuclear extracts isolated from heat-shocked hepatocytes were measured in a gel shift assay. Binding of the heat shock transcription factor to the heat shock element decreased with age and was significantly higher in hepatocyte extracts isolated from old rats fed the caloric restriction diet than in those from old rats fed ad libitum. Thus, our study demonstrates that the ability of hepatocytes to respond to hyperthermia and express hsp70 decreases significantly with age and that this decrease occurs at the transcriptional level. In addition, caloric restriction, which retards aging, reversed the age-related decline in the induction of hsp70 transcription in hepatocytes.

Thermoregulatory and heat-shock protein response deficits in cold-exposed diabetic mice

1996 ◽  
Vol 270 (3) ◽  
pp. R525-R532 ◽  
Author(s):  
J. M. Matz ◽  
K. P. LaVoi ◽  
P. N. Epstein ◽  
M. J. Blake
Keyword(s):  
Heat Shock ◽  
Cold Exposure ◽  
Uncoupling Protein ◽  
Hsp70 Expression ◽  
Diabetic Mice ◽  
Induced Expression ◽  
Hsp70 Mrna ◽  
Brown Adipose ◽  
Shock Proteins ◽  
And Function

Cold-induced expression of heat-shock proteins (HSPs) has been suggested to facilitate thermogenesis in brown adipose tissue (BAT). However, the regulation of this response and the mechanism supporting this facilitation have not been established. Because of the significant role of insulin in maintaining BAT thermogenesis, we employed a transgenic mouse model of diabetes to investigate the regulation and function of HSPs in BAT thermogenesis. These transgenic mice overexpress a calmodulin minigene regulated by the rat insulin II promotor, resulting in severe diabetes characterized by elevated blood glucose and glucagon that coincides with reduced serum and pancreatic insulin. Body temperature (Tb) of diabetic mice dropped significantly faster during a 3-h cold exposure (6 degrees C) than Tb of similarly treated control littermates. Cold exposure resulted in increased levels of constitutive and inducible HSP70 transcripts in control mice, but only constitutive HSP70 mRNA transcripts were induced in diabetic mice. Diabetes did not affect uncoupling protein induction, but cold-induced expression of members of other HSP families was reduced. Correspondingly, heat-shock regulatory factors were not activated in diabetic mice even though these factors were present. Phenylephrine induced HSP70 expression in control and diabetic animals, indicating that alpha-receptor-coupled HSP induction remained intact in BAT of diabetic mice. Insulin replacement restored the Tb response of diabetic mice as well as the HSP response. From these results it is clear that physiological signals that regulate cold-induced activation of BAT also regulate HSP expression in this tissue. This diabetic model provides a novel system in which the HSP response to cold has been selectively knocked out, making it a useful tool for the study of HSP regulation and function in BAT.

scholarly journals Expression of heat shock protein 70 is altered by age and diet at the level of transcription.

1993 ◽  
Vol 13 (5) ◽  
pp. 2909-2918 ◽  
Author(s):  
A R Heydari ◽  
B Wu ◽  
R Takahashi ◽  
R Strong ◽  
A Richardson
Keyword(s):  
Heat Shock ◽  
Caloric Restriction ◽  
Hsp70 Expression ◽  
Mrna Levels ◽  
Age Related ◽  
Restriction Diet ◽  
Old Rats ◽  
Ad Libitum ◽  
Shock Proteins ◽  
Hsp70 Synthesis

Because heat shock proteins have been shown to play a critical role in protecting cells from hyperthermia and other types of physiological stresses, it was of interest to determine what effect age and caloric restriction have on the ability of cells to regulate the expression of heat shock protein 70 (hsp70), the most prominent and most evolutionarily conserved of the heat shock proteins. Caloric restriction is the only experimental manipulation known to retard aging and increase survival of mammals. The ability of hepatocytes isolated from young/adult (4- to 7-month-old) and old (22- to 28-month-old) male Fischer F344 rats fed ad libitum or a caloric restriction diet (60% of the content of the ad libitum diet) to express hsp70 was determined after a mild heat shock (42.5 degrees C for 30 min). We found that the induction of hsp70 synthesis and mRNA levels by heat shock was 40 to 50% lower in hepatocytes isolated from old rats than in hepatocytes isolated from young rats. Using in situ hybridization, we found that essentially all hepatocytes from the young/adult and old rats expressed hsp70 in response to heat shock; therefore, the age-related decrease in the induction of hsp70 expression was not due to an age-related accumulation of cells that do not respond to heat shock. Measurements of hsp70 mRNA stability and hsp70 transcription demonstrated that the age-related decline in hsp70 expression arose from a decline in hsp70 transcription. Interestingly, the age-related decline in the induction of hsp70 expression was reversed by caloric restriction; e.g., the induction of hsp70 synthesis, mRNA levels, and nuclear transcription were significantly higher in hepatocytes isolated from old rats fed the caloric restricted diet than in hepatocytes isolated from old rats fed ad libitum. The levels of the heat shock transcription factor in nuclear extracts isolated from heat-shocked hepatocytes were measured in a gel shift assay. Binding of the heat shock transcription factor to the heat shock element decreased with age and was significantly higher in hepatocyte extracts isolated from old rats fed the caloric restriction diet than in those from old rats fed ad libitum. Thus, our study demonstrates that the ability of hepatocytes to respond to hyperthermia and express hsp70 decreases significantly with age and that this decrease occurs at the transcriptional level. In addition, caloric restriction, which retards aging, reversed the age-related decline in the induction of hsp70 transcription in hepatocytes.

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