Association between heat-shock protein 70 gene polymorphisms and DNA damage in peripheral blood lymphocytes among coke-oven workers.

Hsp70 has been shown to act as a chaperone and be associated with cytoprotection against DNA damage caused by environmental stresses. However, it is unknown whether genetic variation in HSP70 plays a role in stress tolerance and cytoprotection against DNA damage. We determined the frequencies of three polymorphisms, HSP70-1 G190C, HSP70-2 G1267A, and HSP70-hom T2437C from 251 steel-plant workers exposed to coke-oven emission and 130 controls. We estimated the association between the HSP70variants/haplotypes and the levels of DNA damage in their peripheral blood lymphocytes detected by single-cell gel electrophoresis assay. Our results showed that overall coke-oven workers had higher levels of the Olive tail moment (Olive TM) (1.27+/-1.12) than that of the controls (0.56+/-0.99, P<0.001). Coke-oven workers with the HSP70-1 C/C genotype had higher levels of Olive TM (2.19+/-0.65), compared with HSP70-1 G/C and G/G carriers (Olive TM=1.34+/-1.09 and 1.14+/-1.08, respectively, P=0.022 and 0.003, respectively). However, the HSP70-2 G1267A and HSP70-hom T2437C polymorphisms were not associated with the levels of Olive TM (P=0.929 and 0.795, respectively). Haplotype analysis showed that carriers of TCG/TCG haplotype pairs had the highest levels of Olive TM among both the exposed subjects (2.04+/-0.59) and the controls (0.81+/-0.59). Our results suggest that the individuals with the homozygous HSP70-1 C/C genotype among the coke-oven workers may be susceptible to DNA damage.

Benzo(a)pyrene inhibits expression of inducible heat shock protein 70 in vascular endothelial cells.

Benzo(a)pyrene (BaP), a ubiquitous environmental pollutant known to cause many diseases including atherosclerosis, induces a dose-dependent reduction in the levels of the inducible Hsp70. To explore the mechanism underlying the reduction of Hsp70, we measured the levels of Hsp70, cytoplasmic and nuclear heat shock factor 1 (HSF1) in porcine aortic endothelial cells using Western blot, and then further characterized the binding ability of HSF1 and heat shock element (HSE) by electrophoretic mobility shift assay. We found that when porcine aortic endothelial cells were treated by 0.1-10 microM of BaP for 24 h, there was a significant reduction of Hsp70, cytoplasmic and nuclear HSF1 and the binding rate of HSF1 and HSE at 5, 10 microM of BaP but less effective at lower concentrations. The effect of BaP on the Hsp70 expression level was markedly attenuated by co-treatment with phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC). Staurosporine (STP), an inhibitor of PKC, blocked the effect of PMA treatment in combination with BaP. These results suggest that BaP might inhibit Hsp70 levels by reducing the expression of HSF1 and decreasing binding of HSF1 and HSE via PKC-dependent signaling pathways that might be involved in the regulation of Hsp70 gene expression under BaP.

Presence of antibody against the inducible Hsp71 in patients with acute heat-induced illness.

Antibodies against heat shock or stress proteins (Hsps) have been reported in a number of diseases in which they may be involved in the pathogenesis of the disease or may be of use for prognosis. Heat-induced diseases, such as heat cramps, heat exhaustion, or heat stroke, are frequent in hot working or living environments. There are still few investigations on the presence and possible significance of autoantibodies against Hsps in heat-induced illnesses. Using an immunoblotting technique with recombinant human Hsps, we analyzed the presence and titers of antibodies against Hsp60, Hsp71, and Hsp90alpha, and Hsp90beta in a group of 42 young male patients who presented with acute heat-induced illness during training. We also examined the presence of antibody against Hsp71 in a second group of 57 patients with acute heat-induced illness and measured the changes in titers of anti-Hsp71 antibodies in 9 patients hospitalized by emergency physicians. In the first group of young persons exercising in a hot environment, the occurrence of antibodies against Hsp71 and Hsp90alpha was significantly higher among individuals with symptoms of heat-induced illness (P < 0.05) than in the matched group of nonaffected exercising individuals. Moreover titers of antibody against Hsp71 were higher in individuals of the severe and mild heat-induced illness groups, the highest titer being found in the most severe cases. The results from the second group of 57 heat-affected patients exposed to extreme heat were similar. Again, patients with the more severe heat-induced symptoms showed a significantly higher incidence of antibodies to Hsp71 than controls and the titer of anti-Hsp71 was higher in the severely affected group. Finally, in a study of 9 patients, it was observed that the titer of anti-Hsp71 decreased during recovery from severe heat symptoms. These results suggest that measurement of antibodies to Hsps may be useful in assessing how individuals are responding to abnormal stress within their living and working environment and may be used as one biomarker to evaluate their susceptibility to heat-induced diseases.

Evaluation for Hsp70 as a biomarker of effect of pollutants on the earthworm Lumbricus terrestris.

Induction of heat shock proteins (Hsps) is often associated with a cellular response to a harmful stress or to adverse life conditions. The main aims of the present study were (1) to assess if stress-induced Hsp70 could be used to monitor exposure of the earthworm species Lumbricus terrestris to various soil pollutants, (2) to assess the specificity of pollutants in their tissue targeting and in Hsp70 induction, and (3) to evaluate if dose-response relationships could be established and if the stress-response observed was specific. The midgut/intestinal tissues of L. terrestris are shown to express an inducible member of the Hsp70 family after heat shock treatment in vitro and exposures to different soil toxicants in vivo (re: artificial soil). Short-term (24-72 hours) and long-term (14-16 days) exposures to the chemical standards chloroacetamide and pentachlorophenol and to heavy metals (Pb++, Cd++, Cu++, and Hg++) also affected the earthworms, and Hsp70 was induced in their midgut/intestinal tissues. After a 3-day exposure to heavy metals, the level of Hsp70 induction in the midgut/intestinal tissues appears to correlate well with the reported in vivo and in vitro toxicity data. Comparatively, in proximal and midbody wall muscle tissues of animals exposed to the heavy metals, a decrease in expression of Hsp70 was sometimes detected. Thus Hsp analysis by Western blot in L. terrestris tissues and particularly in the midgut/intestine proved to be a suitable and sensitive assay for adverse effects in earthworms and showed a good level of reproducibility despite some individual variations. The use of pristine/nonexposed animals transposed into contaminated environments as in the present study should therefore be of high ecological relevance. Induction of Hsp70 in earthworms should represent not only a good wide-spectrum biomarker of exposure but also a biomarker of effect since known toxicants altered gene expression in tissues of these animals, as contrasted with a simple accumulation of Hsp. Hence, the detection of Hsp70 in earthworms can constitute an early-warning marker for the presence of potentially deleterious agents in soils, with L. terrestris in particular and earthworms in general acting as potential sentinel animal species.

Fumarylacetoacetate, the metabolite accumulating in hereditary tyrosinemia, activates the ERK pathway and induces mitotic abnormalities and genomic instability.

Patients suffering from the metabolic disease hereditary tyrosinemia type I (HT1), caused by fumarylacetoacetate hydrolase deficiency, have a high risk of developing liver cancer. We report that a sub-apoptogenic dose of fumarylacetoacetate (FAA), the mutagenic metabolite accumulating in HT1, induces spindle disturbances and segregational defects in both rodent and human cells. Mitotic abnormalities, such as distorted spindles, lagging chromosomes, anaphase/telophase chromatin bridges, aberrant karyokinesis/cytokinesis and multinucleation were observed. Some mitotic asters displayed a large pericentriolar material cloud and/or altered distribution of the spindle pole-associated protein NuMA. FAA-treated cells developed micronuclei which were predominantly CREST-positive, suggesting chromosomal instability. The Golgi complex was rapidly disrupted by FAA, without evident microtubules/tubulin alterations, and a sustained activation of the extracellular signal-regulated protein kinase (ERK) was also observed. Primary skin fibroblasts derived from HT1 patients, not exogenously treated with FAA, showed similar mitotic-derived alterations and ERK activation. Biochemical data suggest that FAA causes ERK activation through a thiol-regulated and tyrosine kinase-dependent, but growth factor receptor- and protein kinase C-independent pathway. Pre-treatment with the MEK inhibitor PD98059 and the Ras farnesylation inhibitor B581 decreased the formation of CREST-positive micronuclei by approximately 75%, confirming the partial contribution of the Ras/ERK effector pathway to the induction of chromosomal instability by FAA. Replenishment of intracellular glutathione (GSH) with GSH monoethylester abolished ERK activation and reduced the chromosomal instability induced by FAA by 80%. Together these results confirm and extend the previously reported genetic instability occurring in cells from HT1 patients and allow us to speculate that this tumorigenic-related phenomenon may rely on the biochemical/cellular effects of FAA as a thiol-reacting and organelle/mitotic spindle-disturbing agent.

A missense mutation (Q279R) in the fumarylacetoacetate hydrolase gene, responsible for hereditary tyrosinemia, acts as a splicing mutation.

BACKGROUND: Tyrosinemia type I, the most severe disease of the tyrosine catabolic pathway is caused by a deficiency in fumarylacetoacetate hydrolase (FAH). A patient showing few of the symptoms associated with the disease, was found to be a compound heterozygote for a splice mutation, IVS6-1g->t, and a putative missense mutation, Q279R. Analysis of FAH expression in liver sections obtained after resection for hepatocellular carcinoma revealed a mosaic pattern of expression. No FAH was found in tumor regions while a healthy region contained enzyme-expressing nodules. RESULTS: Analysis of DNA from a FAH expressing region showed that the expression of the protein was due to correction of the Q279R mutation. RT-PCR was used to assess if Q279R RNA was produced in the liver cells and in fibroblasts from the patient. Normal mRNA was found in the liver region where the mutation had reverted while splicing intermediates were found in non-expressing regions suggesting that the Q279R mutation acted as a splicing mutation in vivo. Sequence of transcripts showed skipping of exon 8 alone or together with exon 9. Using minigenes in transfection assays, the Q279R mutation was shown to induce skipping of exon 9 when placed in a constitutive splicing environment. CONCLUSION: These data suggest that the putative missense mutation Q279R in the FAH gene acts as a splicing mutation in vivo. Moreover FAH expression can be partially restored in certain liver cells as a result of a reversion of the Q279R mutation and expansion of the corrected cells.

Perinatal expression of heat shock proteins HSC 70 and HSP 70 in neural and non neural tissues of the piglet.

Stress of different kinds during early perinatal life can result in severe consequences for further development. To determine possible involvement of heat shock proteins in brain development, the expression of HSC 70 and HSP 70 was determined in brain regions (cerebellum, cortex, hippocampus, hypothalamus and striatum) and non neural tissues (liver, lungs and kidneys) at birth and during early development of the piglet. In brain regions, HSC 70 expression was decreased during the few hours following birth. With the exception of cortex, hippocampus and kidney where a decrease of expression was observed, HSP 70 did not show significant changes during early development. These results are discussed in terms of using the piglet model of development to study the effect of different kinds of stress like hypoxia or temperature changes on brain development.

Tyrosinemia: a review.

Hypertyrosinemia encompasses several entities, of which tyrosinemia type I (or hepatorenal tyrosinemia, HT1) results in the most extensive clinical and pathological manifestations involving mainly the liver, kidney, and peripheral nerves. The clinical findings range from a severe hepatopathy of early infancy to chronic liver disease and rickets in the older child; gradual refinements in the diagnosis and medical management of this disorder have greatly altered its natural course, mirroring recent advances in the field of metabolic diseases in the past quarter century. Hepatorenal tyrosinemia is the inborn error with the highest incidence of progression to hepatocellular carcinoma, likely due to profound mutagenic effects and influences on the cell cycle by accumulated metabolites. The appropriate follow-up of patients with cirrhosis, the proper timing of liver transplantation in the prevention of carcinoma, and the long-term evolution of chronic renal disease remain important unresolved issues. The introduction of a new pharmacologic agent, NTBC, holds the hope of significantly alleviating some of the burdens of this disease. Mouse models of this disease have permitted the exploration of newer treatment modalities, such as gene therapy by viral vectors, including ex vivo and in utero methods. Finally, recent observations on spontaneous genetic reversion of the mutation in HT1 livers challenge conventional concepts in human genetics.

Structural and functional analysis of missense mutations in fumarylacetoacetate hydrolase, the gene deficient in hereditary tyrosinemia type 1.

Hereditary tyrosinemia type 1 (HT1) is an autosomal recessive disease caused by a deficiency of the enzyme involved in the last step of tyrosine degradation, fumarylacetoacetate hydrolase (FAH). Thus far, 34 mutations in the FAH gene have been reported in various HT1 patients. Site-directed mutagenesis of the FAH cDNA was used to investigate the effects of eight missense mutations found in HTI patients on the structure and activity of FAH. Mutated FAH proteins were expressed in Escherichia coli and in mammalian CV-1 cells. Mutations N16I, F62C, A134D, C193R, D233V, and W234G lead to enzymatically inactive FAH proteins. Two mutations (R341W, associated with the pseudo-deficiency phenotype, and Q279R) produced proteins with a level of activity comparable to the wild-type enzyme. The N16I, F62C, C193R, and W234G variants were enriched in an insoluble cellular fraction, suggesting that these amino acid substitutions interfere with the proper folding of the enzyme. Based on the tertiary structure of FAH, on circular dichroism data, and on solubility measurements, we propose that the studied missense mutations cause three types of structural effects on the enzyme: 1) gross structural perturbations, 2) limited conformational changes in the active site, and 3) conformational modifications with no significant effect on enzymatic activity.

Association of plasma antibodies against the inducible Hsp70 with hypertension and harsh working conditions.

Autoantibodies against certain stress or heat shock proteins (Hsps) may play a role in the pathogenesis and/ or prognosis of some diseases. Using immunoblotting with human recombinant Hsps and univariate and multivariate logistic regression models, we have investigated the presence of antibodies against Hsp70, the inducible member of the 70-kDa family of heat shock proteins, and analyzed its possible association with hypertension and working conditions. Plasma and serum were collected from 764 steel mill workers from 6 work sites exposed to (1) severe noise; (2) severe noise and dust; (3) noise, dust, and heat; (4) noise and heat; (5) severe noise and heat; and (6) office conditions (control). Workers with prolonged exposure to stresses such as noise, dust, and high temperature and a combination of these in the workplace had a high incidence (26.6% to 40.2%) of antibodies to Hsp70 compared to the lowest incidence (18.6%) of antibodies to Hsp70 in the control group of office workers. Moreover, there was a statistical association of antibodies against Hsp70 with hypertension. The statistical correlation between the presence of antibodies to Hsp70 and hypertension is higher in the group of workers with blood pressure of 160/95 mmHg than in the 140/90-mmHg group after excluding possible effects of the workplace stresses. These results suggest that harsh workplace conditions can increase the production of antibodies against Hsp70 and that the presence of antibodies to this stress protein may be associated with hypertension. The precise mechanism for the elevation of antibodies against Hsps by environmental and workplace stresses and their relation to hypertension remains to be established.

The small heat shock protein Hsp22 of Drosophila melanogaster is a mitochondrial protein displaying oligomeric organization.

Drosophila melanogaster has four main small heat shock proteins (Hsps), D. melanogaster Hsp22 (DmHsp22), Hsp23 (DmHsp23), Hsp26 (DmHsp26), and Hsp27 (DmHsp27). These proteins, although they have high sequence homology, show distinct developmental expression patterns. The function(s) of each small heat shock protein is unknown. DmHsp22 is shown to localize in mitochondria both in D. melanogaster S2 cells and after heterologous expression in mammalian cells. Fractionation of mitochondria indicates that DmHsp22 resides in the mitochondrial matrix, where it is found in oligomeric complexes, as shown by sedimentation and gel filtration analysis and by cross-linking experiments. Deletion analysis using a DmHsp22-EGFP construct reveals that residues 1-17 and an unknown number of residues between 17-28 are necessary for import. Site-directed mutagenesis within a putative mitochondrial motif (WRMAEE) at positions 8-13 shows that the first four residues are necessary for mitochondrial localization. Immunoprecipitation results indicate that there is no interaction between DmHsp22 and the other small heat shock proteins. The mitochondrial localization of this small Hsp22 of Drosophila and its high level of expression in aging suggests a role for this small heat shock protein in protection against oxidative stress.

Characterization of the heat-shock protein 60 chaperonin from Onchocerca volvulus.

Chaperonin 60 (cpn60) belongs to the group of ubiquitous molecular chaperones that comprise the heat shock proteins, nucleoplasmins and chaperonins. Antibodies to recombinant CPN60 from humans was used to screen a cDNA library of Onchocerca volvulus and antigen-positive clones were selected. Sequencing of the DNA inserts confirmed their identity as cpn60 transcripts. These are distinct from a cpn60 sequence recorded previously from O. volvulus (GenBank accession number Y09416) that appears to be of endobacterial origin, rather than derived from the parasite itself. The full-length sequence of the cDNA (designated Ov-cpn60) codes for a protein of 64.3kDa (598 amino acid residues) and shares significant identity with homologous gene products from Caenorhabditis elegans (72%), humans (69%), yeast (53%) and Escherichia coli (50%). The endobacterial and parasite sequences are 41% conserved. Ov-CPN60 migrates with an apparent molecular mass of 65kDa on SDS-PAGE and is present in all life-cycle stages, as determined by immunoblotting with rabbit antibodies raised against the recombinant protein. Immunogold electron microscopy identified the protein within mitochondria, as expected, but also in extra-mitochondrial sites, including inclusion bodies of the glandular oesophagus (in infective larvae), the uterine wall, cytosol of developing spermatids, and the hypodermis and cuticle. Endobacteria were also labelled, indicating cross-reactivity between CPN60 from the parasite and its intracellular symbiont. In human infections, serum antibodies to Ov-CPN60 were present in only 11% of cases from Ecuador, but in 81-89% of subjects in three separate foci from West Africa. There was no relationship between antibody levels and age, sex, or infection intensity, and no consistent association between the serological response and immune status. An evaluation of antibody specificities in individual sera revealed a mixture of parasite-specific and host crossreactive anti-CPN60 antibodies, the ratio of which varied amongst geographic areas. It is concluded that antibody responses to Ov-CPN60 are unlikely to contribute either to host protection or pathology in onchocerciasis.

Hepatocellular carcinoma despite long-term survival in chronic tyrosinaemia I.

Tyrosinaemia I (fumarylacetoacetate hydrolase deficiency) is an autosomal recessive inborn error of tyrosine metabolism that produces liver failure in infancy or a more chronic course of liver disease with cirrhosis, often complicated by hepatocellular carcinoma, in childhood or early adolescence. We studied a 37-year-old woman with tyrosinaemia I whose severe liver disease in infancy and rickets during childhood resolved with dietary therapy. From 14 years of age she resumed an unrestricted diet with the continued presence of the biochemical features of tyrosinaemia, yet maintained normal liver function. In adult years she accumulated only small amounts of succinylacetone. Despite this evolution to a mild biochemical and clinical phenotype, she eventually developed hepatocellular carcinoma. Her fumarylacetoacetate hydrolase genotype consists of a splice mutation, IVS6-1g>t, and a novel missense mutation, Q279R. Studies of resected liver demonstrated the absence of hydrolytic activity and of immunological expression of fumarylacetoacetate hydrolase in liver tumour. In nontumoral areas, however, 53% of normal hydrolytic activity and immunologically present fumarylacetoacetate hydrolase was found. This case demonstrates the high risk of liver cancer in tyrosinaemia I even in a seemingly favourable biological environment.

Cyclin B-dependent kinase and caspase-1 activation precedes mitochondrial dysfunction in fumarylacetoacetate-induced apoptosis.

Hereditary tyrosinemia type I is the most severe metabolic disease of the tyrosine catabolic pathway mainly affecting the liver. It is caused by deficiency of fumarylacetoacetate hydrolase, which prevents degradation of the toxic metabolite fumarylacetoacetate (FAA). We report here that FAA induces common effects (i.e., cell cycle arrest and apoptosis) in both human (HepG2) and rodent (Chinese hamster V79) cells, effects that seem to be temporally related. Both the antiproliferative and apoptosis-inducing activities of FAA are dose dependent and enhanced by glutathione (GSH) depletion with L-buthionine-(S,R)-sulfoximine (BSO). Short treatment (2 h) with 35 microM FAA/+BSO or 100 microM FAA/-BSO induced a transient cell cycle arrest at the G2/M transition (20% and 37%, respectively) 24 h post-treatment. In cells treated with 100 microM FAA/-BSO, an inactivation, followed by a rapid over-induction of cyclin B-dependent kinase occurred, which peaked 24 h post-treatment. Maximum levels of caspase-1 and caspase-3 activation were detected at 3 h and 32 h, respectively, whereas release of mitochondrial cytochrome c was maximal at 24-32 h post-treatment. The G2/M peak declined 24 h later, concomitantly with the appearance of a sub-G1, apoptotic population showing typical nucleosomal-sized DNA fragmentation and reduced mitochondrial transmembrane potential (Deltapsi(m)). These events were prevented by the general caspase inhibitor z-VAD-fmk, whereas G2/M arrest and subsequent apoptosis were abolished by GSH-monoethylester or N-acetylcysteine. Other tyrosine metabolites, maleylacetoacetate and succinylacetone, had no antiproliferative effects and induced only very low levels of apoptosis. These results suggest a modulator role of GSH in FAA-induced cell cycle disturbance and apoptosis where activation of cyclin B-dependent kinase and caspase-1 are early events preceding mitochondrial cytochrome c release, caspase-3 activation, and Deltapsi(m) loss. -Jorquera, R., Tanguay, R. M. Cyclin B-dependent kinase and caspase-1 activation precedes mitochondrial dysfunction in fumarylacetoacetate-induced apoptosis.

The nuclear chronicles: gene transcription and molecular traveling.

The transfer and processing of an RNA transcript from its locus of transcription on chromatin through the nuclear membrane to its site of translation on cytoplasmic ribosomes is a long and complex journey involving numerous processes and interactions with various macromolecules. These various steps that regulate gene expression were the subject of the 9th Winternational Symposium of the Canadian Society of Biochemistry and Molecular & Cell Biology held at Manoir du Lac Delage, a small resort centre north of Quebec City on February 12-15, 1999.

SUMO/sentrin: protein modifiers regulating important cellular functions.

Regulation of protein functions can be achieved by posttranslational protein modifications. One of the most studied modifications has been conjugation to ubiquitin, which mainly targets substrate proteins for degradation by the 26 S proteasome. Recently, SUMO/sentrin, a ubiquitin-like protein has been characterized. This evolutionary conserved protein is conjugated to specific proteins in a way similar, but not identical, to ubiquitin and seems also to be involved in the regulation of protein localization or function. An increasing number of SUMO/sentrin substrates are currently described. We focus here on three major substrates of modification by SUMO: RanGAP1, PML, and IkappaBalpha proteins. These different examples illustrate how SUMO conjugation may be involved in the control of the level of critical proteins within the cell or in the modulation of subcellular localization and nucleocytoplasmic trafficking.

Genotyping of a case of tyrosinaemia type I with normal level of succinylacetone in amniotic fluid.

Tyrosinaemia type I is caused by a deficiency of fumarylacetoacetate hydrolase and mainly affects the liver. This disease is characterized by the presence of a high level of succinylacetone. This metabolite has been used for prenatal diagnosis from amniotic fluid samples. One case with a normal level of succinylacetone in amniotic fluid has recently been described (Grenier et al., 1996). Here, we report that this patient is a compound heterozygote for two known mutations: E364X and IVS6-1g-->t. The low level of succinylacetone cannot be explained by these mutations.

Biochemical changes of plasma in paratroops after parachuting: a preliminary investigation.

OBJECTIVE: To study whether physiological and psychological stresses during parachuting jumps may result in biochemical changes of plasma in parachutists. METHOD: Differences in the levels of hormones (cortisol, growth hormone, insulin, pancreatic glucagon, endothelin, angiotonin I and II, aldosterone), activities of enzymes (superoxide dismutase, glutathione peroxidase, glutathione S transferase), levels of the free radical damage indicator malondialdehyde (MDA), tumor necrosis factor alpha (TNF-alpha), and the main heat stress protein, HSP70, in the plasma and serum were investigated in control (non-parachuting) and parachuting paratroops. RESULT: Significantly higher levels of serum hormones such as growth hormone, insulin, angiotonin 1, renin activities, as well as MDA and plasma TNF-alpha and HSP70 were observed in the parachuting group. CONCLUSION: Whether these changes can potentially serve as useful biomarkers to assess possible abnormal stress in parachutists and to evaluate the health condition and to select parachutists remains to be further studied.

Expression of heat shock proteins in mouse skin during wound healing.

Wound healing conditions generate a stressful environment for the cells involved in the regeneration process and are therefore postulated to influence the expression of heat shock proteins (Hsps). We have examined the expression of four Hsps (Hsp27, Hsp60, Hsp70 and Hsp90) and a keratin (keratin 6) by immunohistochemistry during cutaneous wound repair from Day 1 to Day 21 after wounding in the mouse. Hsps were constitutively expressed in normal mouse epidermis and their patterns of expression were modified during the healing process. The changes were not directly linked to the time course of the healing process but rather were dependent on the location of cells in the regenerating epidermis. In the thickened epidermis, Hsp60 was induced in basal and low suprabasal cells, Hsp70 showed a reduced expression, and Hsp90 and Hsp27 preserved a suprabasal pattern with an induction in basal and low suprabasal cells. All Hsps had a uniform pattern of expression in the migrating epithelial tongue. These observations suggest that the expression of Hsps in the neoepidermis is related to the proliferation, the migration, and the differentiation states of keratinocytes within the wound.

Presence of antibodies to heat stress proteins in workers exposed to benzene and in patients with benzene poisoning.

Heat shock or stress proteins (Hsps) are a group of proteins induced by a large number of xenobiotics, many of which are common in the working and living environment. The biological significance of the presence of antibodies against Hsps in humans is presently unknown. In the present study, 112 workers were selected and divided into four groups on the basis of their level of occupational exposure to benzene: a control group, two groups of workers exposed to either low (< 300 mg/m3) or high concentrations of benzene (> 300 mg/m3) and a group of workers who had experienced benzene poisoning. Blood samples from these workers were assayed for the number of peripheral white blood cells, concentration of hemoglobin, activities of serum superoxide dismutase (SOD), lymphocyte DNA damage and finally for the presence of antibodies to different human heat-shock proteins (Hsp27, Hsp60, Hsp71 and Hsp90). Benzene-poisoned workers showed a high incidence of antibodies against Hsp71 (approximately 40%) which was associated with a decrease in white blood cells (3.84+/-1.13 x 10(9)versus 7.68+/-1.84 x 10(9) in controls) and with an increase in activities of serum SOD (138.43+/-23.15 micro/ml) and lymphocyte DNA damage (18.7%). These data suggest that antibodies against Hsps can potentially be useful biomonitors to assess if workers are experiencing or have experienced abnormal xenobiotic-induced stress within their living and working environment.