Trauma-induced protein in rat tissues: a physiological role for a "heat shock" protein?

O-phenantroline-CuSO4-induced redistribution of nuclear proteins

Incubation of rat liver nuclei with the o-phenantroline-CuSO4 (OP-Cu) complex under conditions not causing any DNA cleavage, enhanced the susceptibility of chromatin to the action of micrococcal nuclease. The released nucleosomal fraction had less coextracted nonhistone proteins, while the nuclear matrix was enriched in nonhistone proteins when compared with the controls. These changes were interpreted as the consequence of a displacement of nonhistone proteins from their closer association with the chromatin complex and a concomitant exposure of chromatin regions in a state less protected by nonhistone proteins.

Postnatal development of a cellular response to stress in rat brain

In vivo synthesis of a stress protein (SP71) in response to hyperthermia was examined in brain and several other tissues from rats ranging in age from 1 day to 25 weeks old. The synthesis of SP71 was increased dramatically by hyperthermia at all ages in all tissues examined except brain. We were unable to detect any increase in SP71 synthesis in brain due to hyperthermia until the rats were more than 2 weeks old. SP71 synthesized by the cerebral microvasculature in response to the trauma of tissue slicing has previously been reported to show a similar requirement for postnatal development. The onset of the increase in synthesis of SP71 in response to either mild hyperthermia or mechanical trauma correlates with the structural and functional maturation of the cerebral microvasculature and the blood-brain barrier.

Analysis of the temperature-dependent temporal pattern of heat-shock-protein synthesis in fish cells

Continuous exposure of Chinook salmon embryo cells to an elevated incubation temperature of 24 degrees C induces the transient expression of a set of heat-shock or stress proteins whereas maintenance of the cells at a higher incubation temperature of 28 degrees C produces a continuous synthesis of these stress proteins. In vitro translation studies suggest that the temperature-dependent temporal pattern of stress-protein synthesis is correlated with the levels of stress-protein mRNA. This was verified using a recombinant-DNA probe complementary to the 70K heat-shock-protein mRNA. A transient increase in the level of the fish heat-shock 70K mRNA was observed in RNA samples isolated from cells continuously exposed at 24 degrees C. However, a constant increase in the level of this specific mRNA was found in RNA preparations obtained from cells maintained at 28 degrees C. Therefore, the temperature-dependent pattern of fish heat-shock-protein synthesis appears to be directly related to the level of heat-shock-protein mRNA.

Induction of a stress protein in developing cell cultures of the rat cerebellum

We examined the ability of developing cerebellar cell cultures to synthesize a 71,000 MW stress protein (SP71) in response to heat shock and Cd2+ treatment. The induction of SP71 synthesis appeared to be dependent on both the age of the culture and the stressor used. Heat shock induced SP71 synthesis in freshly prepared cells and in cell cultures at each age examined, whereas Cd2+ was effective only in cultures at 7 days of age and older. These findings are discussed with reference to the development of various cell types in these cultures.

Similarities in properties, content, and relative rates of synthesis of fructose-P2 aldolase in livers of fed and starved rats

The present work gives evidence that, in contrast to the situation reported by Pontremoli et al. for the rabbit (Proc, Natl. Acad. Sci. U.S.A. 76, 6323-6325, 1979; Arch. Biochem. Biophys. 203, 390-394, 1980; Proc. Natl. Acad. Sci. U.S.A, 79, 5194-5196, 1982), starvation for as long as 3 days does not cause intracellular covalent modification and inactivation of fructose-P2 aldolase molecules in rat liver cells. This conclusion is based on our observations that liver aldolase molecules isolated from fed and starved rats in the presence of proteolytic inhibitors were not distinguished on the basis of specific catalytic activity, electrophoretic mobility, subunit molecular weight, NH2-terminal structure, or COOH-terminal structure. Further, the approximate 40% loss in rat liver mass which occurred during the 3-day fast was not associated with appreciable changes in the content of aldolase and most other abundant cytosolic proteins per gram of rat liver, as judged by electrophoretic analysis of 100 000-g soluble fractions of liver extracts. Finally, a 3-day fast had no appreciable effect on the relative rates of synthesis of aldolase and most other abundant cytosolic proteins in rat liver. Our findings suggest that nutrient deprivation has no preferential effect on the concentration or metabolism of aldolase in rat liver cells.

Humoral factors in regulation of compensatory renal hypertrophy

Compensatory renal hypertrophy in transplanted kidneys shows that the major regulators are humoral. Crosscirculation experiments are confirmatory indicating further that the regulators are short-lived and must be consistently present during the early phases of hypertrophy. Controls are difficult to achieve in other systems; variables relate to nutrition, means of assay, pharmacokinetics, and abnormalities produced by the experimental model itself. A simple hypothesis to account for the events precipitating renal hypertrophy might integrate the onsets of renal hyperemia soon after contralateral nephrectomy with the activation of pre-existing stimulators specific for the kidney.

Thermal trauma-induced changes in the synthesis of rat serum proteins

Infliction of non-lethal scalding was found to cause an increase in the rate of incorporation of 35S-methionine into albumin and globulin fractions of rat serum proteins, the the increase being remarkably higher for alpha- and beta-globulins than for albumin and gamma-globulins The most pronounced enhancement was associated with the 60- and 70-kd constituents of beta-globulins, the 34-, 55- and 136-kd polypeptides of alpha-2-globulins and the 50-, 60-, 125- and 145-kd polypeptides of alpha-1-globulins. The response of serum proteins to the heat shock was similar, though the changes were significantly less pronounced.

Heat shock protein in mammalian brain and other organs after a physiologically relevant increase in body temperature induced by D-lysergic acid diethylamide

A physiologically relevant increase in body temperature from 39.7 to 42.5 degrees C, which was generated after the intravenous injection of D-lysergic acid diethylamide (LSD), caused the induction of synthesis of a 74,000-dalton heat shock protein in the brain, heart, and kidney of the young adult rabbit. A marked increase in the relative labeling of a 74,000-dalton protein was noted after analysis of both in vivo labeled proteins and cell-free translation products of isolated polysomes. A temporal decrease in the synthesis of this protein was noted as LSD-induced hyperthermia subsided. The 74,000-dalton protein, which is induced in various organs of the intact animal at a body temperature similar to that attained during fever reactions, may play a role in homeostatic control mechanisms.

Massive heat-shock polypeptide synthesis in late chicken embryos: convenient system for study of protein synthesis in highly differentiated organisms

In cultured eucaryotic cells, heat treatments specifically induced the rapid synthesis of the so-called heat-shock polypeptides. To ascertain the physiological importance of this phenomenon for highly differentiated organisms, we attempted to determine whether the heat-shock response occurs in a living endothermic organism at extreme temperatures, and if so, whether the response is organ specific. We developed a procedure to label proteins efficiently in 5- to 18-day-old chicken embryos. Heat-shock polypeptides of identical sizes of 85,000, 70,000, and 25,000 daltons were synthesized predominantly in chicken embryo fibroblasts and in many different organs of 18-day-old embryos at 42.5 to 44 degrees C.

Diverse forms of stress lead to new patterns of gene expression through a common and essential metabolic pathway

Many eukaryotic organisms respond to heat shock by synthesizing new proteins. We examined the possibility that heat shock proteins represent a particular expression of a general response to stress and that, regardless of the nature of the effective stimulus, the same proteins are synthesized. Accordingly, cardiac stress was applied in the intact rat by four methods: banding the ascending aorta, increasing body temperature to 42 degrees C, reducing body temperature to 18 degrees C, and forcing the rat to swim until exhausted. The hearts were then extirpated and analyzed for new mRNA synthesis. The extracted RNA was translated in a cell-free medium containing [35S]methionine. Translation products were resolved by two-dimensional electrophoresis and visualized by autoradiography. Lactic acid concentration in heart tissue was determined enzymatically. The results showed that two new and distinct proteins of Mr 71,000 and isoelectric points of 5.8 and 6.1 were synthesized in hearts stressed by banding and by heating but not in hearts of exhausted swimmers or in animals at reduced body temperatures. There was no significant difference in cardiac lactic acid concentration between control hearts and hearts from swimmers or cold-treated animals. However, there was a 2-fold increase in lactic acid concentration in hearts of rats with banded aortas compared to controls and a 10-fold increase in heat shocked hearts. We conclude that, under conditions in which the energy requirements of the heart are not completely met by aerobic processes, the resultant lactic acidosis creates an intracellular environment that leads to the selective activation of genes, the production of new mRNA, and the synthesis of a typical group of stress proteins.

Correlation between synthesis of heat shock proteins and development of thermotolerance in Chinese hamster fibroblasts

Synthesis of a family of proteins called "heat shock" proteins is induced or enhanced in cells in response to various environmental stresses, suggesting that these proteins may perform functions essential to cell survival. Because a brief, nonlethal heat treatment can dramatically induce a transient resistance to a subsequent lethal heat treatment (thermotolerance), we examined the effect of heat treatment (41-46 degrees C) on protein synthesis and cell survival in plateau-phase Chinese hamster fibroblast (HA-1) cells. After heat treatments that either drastically inhibited total protein synthesis (46 degrees C) or did not suppress it (41 degrees C), the synthesis of heat shock proteins was greatly enhanced over that in unheated cells, and cell survival was increased 10(2)- to 10(6)-fold when cells were challenged by a subsequent lethal heat treatment. The synthesis of heat shock proteins correlated well with the development of thermotolerance, and the stability of these proteins correlated well with the persistence of thermotolerance up to 36 hr. Sodium arsenite, hypoxia, and ethanol also induced both the synthesis of heat shock proteins and transient thermotolerance. A qualitative analysis of individual proteins suggests that the synthesis and persistence of polypeptides of Mr 70,000 or 87,000 most closely conformed to the kinetics of thermotolerance.

Massive heat-shock polypeptide synthesis in late chicken embryos: convenient system for study of protein synthesis in highly differentiated organisms

In cultured eucaryotic cells, heat treatments specifically induced the rapid synthesis of the so-called heat-shock polypeptides. To ascertain the physiological importance of this phenomenon for highly differentiated organisms, we attempted to determine whether the heat-shock response occurs in a living endothermic organism at extreme temperatures, and if so, whether the response is organ specific. We developed a procedure to label proteins efficiently in 5- to 18-day-old chicken embryos. Heat-shock polypeptides of identical sizes of 85,000, 70,000, and 25,000 daltons were synthesized predominantly in chicken embryo fibroblasts and in many different organs of 18-day-old embryos at 42.5 to 44 degrees C.

Translation of mRNA associated with monosomes and residual polysomes following disaggregation of brain polysomes by LSD and hyperthermia

Intravenous administration of LSD to young adult rabbits induces a transient disaggregation of brain polysomes and a relocalization of mRNA from polysomes to monosomes. To analyze the spectrum of mRNA molecules which were associated with either the residual polysomes or the translationally inactive monosome complex, these two fractions were isolated on sucrose gradients and translated in a reticulocyte cell-free system. Analysis of [35S]methionine labeled translation products by one and two dimensional gel electrophoresis revealed that a full spectrum of mRNA molecules was relocalized from polysomes to monosomes following drug induced polysome disaggregation. The only exception was the mRNA coding for the LSD-induced 74K protein which was associated with the residual polysome fraction and not with the monosome complex. This brain protein is similar in molecular weight to one of the major 'heat shock' proteins which are induced in tissue culture cells following elevation of ambient temperature and disaggregation of existing polysomes. The mRNA coding for the 74K brain protein was not observed in polysomes isolated following blockage of LSD-induced hyperthermia but it was noted when hyperthermia was induced by elevation of ambient temperature. The mRNA species coding for the 74K protein was polyadenylated.

Effect of actinomycin D and cycloheximide on experimental myocardial infarction in rats

Actinomycin D, an inhibitor of DNA-directed RNA synthesis, or cycloheximide, a protein synthesis inhibitor, administered 24 h and 1 or 4 h respectively, before inducing coronary occlusion in conscious rats, offered marked protection against postinfarction ventricular fibrillation and sudden death. When actinomycin D was given 4 h prior to coronary ligation, the outcome of myocardial infarction was not influenced, the well-established cardioprotective effect of dexamethasone was however completely abolished. These results suggest that protein factors may be involved in the early events of myocardial infarction.