Various genes have evolved to protect the cell against stressor-induced damage or death including the heat shock proteins (HSPs). Stressor-induced HSP gene expression involves the activation of heat shock factor (HSF), which binds to the heat shock element (HSE) found in the promoter region of <em>hsp</em> genes. Previously, our laboratory has examined the expression and function of <em>hsp</em> genes in the South African clawed frog, <em>Xenopus laevis</em>. Amphibians are particularly susceptible to adverse environmental conditions, including high temperatures and toxicants. In contrast to the many known inducers of HSF activation in poikilothermic vertebrates, few inhibitors have been either discovered or described in the literature. The present study has compared for the first time the effect of two heat shock response (HSR) inhibitors, quercetin and KNK437, on <em>hsp</em> gene expression in <em>Xenopus</em> A6 cells, demonstrating their efficacy in poikilotherms. Northern blot and densitometric analysis showed that cells treated with either quercetin or KNK437 decreased the heat shock-induced accumulation of <em>hsp70</em>, <em>hsp47</em>, and <em>hsp30</em> mRNAs. Additionally, constitutive levels of <em>hsp47</em> and <em>hsc70</em> mRNAs were reduced. In comparison, neither quercetin nor KNK437 affected the levels of constitutively expressed <em>ef1&alpha;</em> mRNAs under control or heat shock conditions. Western blot and densitometric analysis in this study showed that under heat shock conditions, exposure to quercetin or KNK437 significantly decreased the accumulation of HSP30, and that KNK437 was more effective in doing so than quercetin. In comparison, levels of actin were not significantly affected by either heat shock or exposure to DMSO, quercetin, or KNK437. These findings suggest that one mechanism by which quercetin and KNK437 inhibits the HSR in <em>Xenopus</em> is through the inhibition of HSF activity. <br /><br /> Results of this study also suggest that KNK437 inhibits the acquisition of thermotolerance in poikilotherms, similar to observations in mammalian systems. In the presence of KNK437, cells given a 2 h heat pretreatment at 33ºC followed by a thermal challenge for 1 h at 37ºC, showed numerous ruffled membrane edges and some aggregates of disrupted stress fibers. In comparison, cells directly challenged for 1 h at 37ºC, showed a marked decrease in HSP30, which was located predominantly at the cellular periphery in conjunction with actin aggregates. These cells showed virtually no intact stress fibers spanning cells and no coherent cell-cell connections. A 3-D analysis of cells given a 1 h thermal challenge at 37ºC (after a prior 2 h heat shock at 33ºC) in the absence of KNK437, showed numerous linear actin bundles transversing the entire cell, even extending into areas of cell-cell contact, and abundant HSP30 concentrated in the perinuclear region surrounding an intact nucleus. However, in the presence of KNK437, there was a significant emergence of membrane ruffles indicating global instability of cellular adhesion. This study has demonstrated that KNK437, which is the more specific and efficient HSR inhibitor, will be an important inhibitor to compare with the well-documented quercetin for future investigations.

The heat shock or stress response is a transient response to stressful stimuli that protects vital cellular proteins from damage and irreversible aggregation. Heat shock proteins (Hsps) are molecular chaperones that bind to unfolded protein and inhibit their aggregation, thereby maintaining their solubility until they can be refolded to their native conformation. Hsp47 is an endoplasmic reticulum (ER)-resident protein that serves as a molecular chaperone during collagen production. Collagen is the major class of insoluble fibrous protein found in the extracellular matrix and in connective tissues. It is the single most abundant protein of the animal kingdom; at least 14 different forms exist, each with distinct structures and binding properties. The various types of collagen all possess protein regions with the distinct triple helical conformation. This complex physical structure requires very organized assembly and HSP47 has been established as an integral component of this process for collagen types I-V. Most of the previous studies examining the expression and function of hsp47 have been conducted with mammalian cultured cells. The present study represented the first investigation of the expression of hsp47 in the poikilothermic vertebrate, <i>Xenopus laevis</i>. Full-length <i>Xenopus</i> hsp47 nucleotide and amino acid sequences were obtained from Genbank and compared with hsp47 from chicken, mouse, rat, human and zebrafish. <i>Xenopus</i> HSP47 protein had an identity of approximately 77% with chicken, 73% with mouse, 72% with rat and human, and 70% with zebrafish. Most of the sequence identity between HSP47 from all investigated organisms occurred centrally in the amino acid sequence and in several carboxyl terminal regions. Three key features were conserved between HSP47 proteins from most species investigated: a hydrophobic leader sequence, two potential glycosylation sites and the ER-retention signal, RDEL. A partial cDNA clone encoding <i>Xenopus</i> hsp47 was obtained from the American Type Culture Collection (ATCC) and used to generate hsp47 antisense riboprobe for the purpose of investigating hsp47 mRNA accumulation in <i>Xenopus</i> A6 kidney epithelial cells and embryos. Northern blot analysis detected hsp47 mRNA constitutively in A6 cells. The expression pattern for hsp47 mRNA was compared with two other <i>Xenopus</i> heat shock proteins that have been previously characterized in our laboratory: hsp70, a cystolic/nuclear hsp and BiP, an ER-resident hsp. The results of hsp47 mRNA accumulation in A6 cells suggested that the expression pattern for <i>Xenopus</i> hsp47 was unique but, with respect to some stressors, resembled that of a cytosolic hsp rather than an ER-resident hsp. HSP47 protein levels were also examined in A6 cells. Heat shock, sodium arsenite and b-aminopropionitrile fumerate treatments enhanced hsp47 accumulation. In some experiments, western blot analysis revealed the presence of two closely sized protein bands. It is possible that minor differences in HSP47 protein size may be due to post-translational modification, namely phosphorylation or glycosylation. The present study also examined the accumulation and spatial pattern of hsp47 mRNA accumulation during <i>Xenopus laevis</i> early development. Hsp47 was constitutively expressed throughout <i>Xenopus</i> early development. Constitutive levels of hsp47 mRNA in unfertilized eggs, fertilized eggs and cleavage stage embryos indicated that these transcripts were maternally inherited. Constitutive hsp47 mRNA accumulation was enhanced in neurula and tailbud embryos compared to earlier stages. This finding may be explained by the shift towards organogenesis during these stages. Whole mount <i>in situ</i> hybridization revealed hsp47 message along the dorsal region of the embryo, in the notochord and somites, as well as in the head region including the eye vesicle. Hsp47 mRNA induction in <i>Xenopus</i> embryos was also examined in response to heat shock. Hsp47 mRNA accumulated in response to heat shock immediately following the midblastula transition (MBT). In tailbud stages, hsp47 mRNA accumulated in the notochord, somites and head region. Northern blot analysis and whole mount <i>in situ</i> hybridization results revealed an expression pattern that coincided well with the development of collagen-rich tissues thereby substantiating the proposed role of HSP47 as a procollagen molecular chaperone.

Various genes have evolved to protect the cell against stressor-induced damage or death including the heat shock proteins (HSPs). Stressor-induced HSP gene expression involves the activation of heat shock factor (HSF), which binds to the heat shock element (HSE) found in the promoter region of <em>hsp</em> genes. Previously, our laboratory has examined the expression and function of <em>hsp</em> genes in the South African clawed frog, <em>Xenopus laevis</em>. Amphibians are particularly susceptible to adverse environmental conditions, including high temperatures and toxicants. In contrast to the many known inducers of HSF activation in poikilothermic vertebrates, few inhibitors have been either discovered or described in the literature. The present study has compared for the first time the effect of two heat shock response (HSR) inhibitors, quercetin and KNK437, on <em>hsp</em> gene expression in <em>Xenopus</em> A6 cells, demonstrating their efficacy in poikilotherms. Northern blot and densitometric analysis showed that cells treated with either quercetin or KNK437 decreased the heat shock-induced accumulation of <em>hsp70</em>, <em>hsp47</em>, and <em>hsp30</em> mRNAs. Additionally, constitutive levels of <em>hsp47</em> and <em>hsc70</em> mRNAs were reduced. In comparison, neither quercetin nor KNK437 affected the levels of constitutively expressed <em>ef1&alpha;</em> mRNAs under control or heat shock conditions. Western blot and densitometric analysis in this study showed that under heat shock conditions, exposure to quercetin or KNK437 significantly decreased the accumulation of HSP30, and that KNK437 was more effective in doing so than quercetin. In comparison, levels of actin were not significantly affected by either heat shock or exposure to DMSO, quercetin, or KNK437. These findings suggest that one mechanism by which quercetin and KNK437 inhibits the HSR in <em>Xenopus</em> is through the inhibition of HSF activity. <br /><br /> Results of this study also suggest that KNK437 inhibits the acquisition of thermotolerance in poikilotherms, similar to observations in mammalian systems. In the presence of KNK437, cells given a 2 h heat pretreatment at 33ºC followed by a thermal challenge for 1 h at 37ºC, showed numerous ruffled membrane edges and some aggregates of disrupted stress fibers. In comparison, cells directly challenged for 1 h at 37ºC, showed a marked decrease in HSP30, which was located predominantly at the cellular periphery in conjunction with actin aggregates. These cells showed virtually no intact stress fibers spanning cells and no coherent cell-cell connections. A 3-D analysis of cells given a 1 h thermal challenge at 37ºC (after a prior 2 h heat shock at 33ºC) in the absence of KNK437, showed numerous linear actin bundles transversing the entire cell, even extending into areas of cell-cell contact, and abundant HSP30 concentrated in the perinuclear region surrounding an intact nucleus. However, in the presence of KNK437, there was a significant emergence of membrane ruffles indicating global instability of cellular adhesion. This study has demonstrated that KNK437, which is the more specific and efficient HSR inhibitor, will be an important inhibitor to compare with the well-documented quercetin for future investigations.

Cadmium is a highly toxic chemical and has been classified by the International Agency for Research on Cancer as a human carcinogen. Cadmium is abundant in the environment, at specific work places, and in food and water. Toxicological responses to cadmium exposure include respiratory diseases, neurological disorders and kidney damage. The present study examined the effects of cadmium on heat shock protein (HSP) accumulation in Xenopus laevis A6 kidney epithelial cells. HSPs are molecular chaperones involved in protein folding and translocation. In response to environmental stress these proteins bind to unfolded protein and inhibit their aggregation. Stress-inducible hsp gene transcription is mediated by the heat shock promoter element (HSE), which interacts with heat shock transcription factor (HSF). In the present study, hsp30 and hsp70 mRNA and protein were induced by heat shock, as determined by northern and western blot analysis. Exposure of A6 cells to cadmium chloride also induced the expression of hsp genes. For example, northern and western blot analysis revealed that exposure of A6 cells to cadmium chloride induced the accumulation of hsp30 and hsp70 mRNA and their respective proteins. Western blot analysis also revealed that A6 cells recovering from a cadmium chloride treatment retained relatively high levels of HSP30 and HSP70 protein accumulation over 24 h after the removal of the stress. Treatments combining a mild heat shock and cadmium chloride resulted in a synergistic increase in hsp30 and hsp70 gene expression at mRNA and protein levels. Further experiments in which two stressors were combined revealed that synergistic effects occurred with varying cadmium concentrations and different temperatures. Immunocytochemistry and confocal microscopy were used to confirm the results attained from western blot analysis. Further, this technique allowed the determination of intracellular localization of HSP30 in A6 cells and the examination of cellular morphology and cytoskeletal structure during cadmium chloride treatments. A 2 h heat shock at 33°C resulted in the accumulation of HSP30 in the cytoplasm, whereas a 2 h heat shock at 35°C resulted in some HSP30 accumulation in the peripheral region of the nucleus. This is in contrast to cells treated with cadmium chloride, where HSP30 accumulation was restricted to the cytoplasm. A 14 h 50 μM cadmium chloride treatment resulted in the accumulation of HSP30 in approximately 10% of cells. The proportion of cells displaying HSP30 accumulation increased to 80% and 95% in cells treated with 100 μM and 200 μM, respectively. HSP30 accumulation frequently occurred in large granular structures. High concentrations of cadmium chloride resulted in cell membrane ruffling at areas of cell-cell contact, as well as actin disorganization. This study characterized the pattern of hsp gene expression, accumulation and localization under various cadmium chloride conditions. These results suggest that hsp30 and hsp70 gene expression can be used as potential biomolecular markers for cadmium exposure.

Stress-induced heat shock protein (HSP) gene transcription is controlled primarily by the transcription factor heat shock factor 1 (HSF1). HSF1 activation involves trimerization, heat shock element (HSE)-binding, and transactivation. During prolonged stress or upon removal of stress HSF1 activity attenuates. The mechanism(s) regulating HSF1 activity are unknown. Some reports have suggested that HSF1 may be regulated in some manner by the HSP90 chaperone (Nadeau, K., 'et.al.', 1993; Nair, S., 'et.al.', 1996). Utilizing the 'Xenopus' oocyte model system I tested the hypothesis that the HSP90 chaperone machine, known to function in the folding and maturation of molecules such as steroid receptors, might also participate in HSF1 regulation. Characterization experiments illustrated that the 'Xenopus' oocyte was capable of responding to some but not all forms of stress at the level of HSF1-HSE binding illustrating that certain stress pathways may be absent or inactive in the oocyte. Through transcriptional assaysit was also shown that HSF1-DNA binding and transactivation are regulated by independent mechanisms in the oocyte. HSP90 was shown to interact with and regulate the activity of HSF1 in oocytes. HSP90-HSF1 associations were illustrated ' in vivo' and 'in vitro' by co-immunoprecipitation and gel supershift assays. Immunotargeting HSP90 caused activation of HSF1 under control conditions and delayed deactivation during recovery. These data support a role for HSP90 in the oligomeric changes associated with HSF1 activation/deactivation. Immunotargeting HSP90 also inhibited HSF1 dependent transcription, supporting a role for HSP90 in mediating HSF1 transcriptional activity. HSP90 does not regulate HSF1 alone. Gel supershift analysis showed that p23, HSP90 and FKBP52 exist in a complex with activated HSF1. Furthermore, elevating the levels of various co-chaperones through injection of protein or mRNA had various effects on HSF1 during recovery from stress. Immunotargeting HSP90 or p23 induced HSF1-DNA binding in the absence of stress indicating these proteins may act together to repress HSF1 'in vivo'. Furthermore, injection of HSP90, Hip, Hop, p23, FKBP51, and FKBP52 antibodies significantly delayed HSF1 deactivation supporting a role for these proteins in trimer disassembly. Therefore multiple components of the HSP90 chaperone complex function to regulate HSF1 during its activation and/or deactivation cycle.

Purpose: Excessive day time sleepiness, sleep disorders and neurobehavior changes are common clinical observations in the patients with epilepsy. From literature review, they were highly related with epilepsy risk characteristics (age of onset, types or numbers of drugs, seizure frequency), co-morbidities or neuronal network changes. The serological biomarkers have been reported to reflect the phenomenon of seizure, while their correlations with neurobehavior changes were still not concluded. There were two purposes of this thesis. (1) To understand the relationship between sleep disturbance with day time performances (2) To understand the relationships between serological biomarkers, neurobehavior performances and neuronal networks in patients with temporal lobe epilepsy. Material and Methods: The study enrolled patients from epilepsy outpatient clinic. By using self-appreciated questionnaire (The Pittsburgh Sleep Quality Index, The Epworth Sleepiness Scale, Euroqol Quality of Life Scale-5D), we collected the characteristics of sleep related behavior and life quality changes and explored the relationship with epilepsy risk characteristics. In patients with temporal lobe epilepsy, we assessed the neurobehavior performances, measured the serological biomarkers (heat shock protein 70, S100£]protein, neuron specific enolase, brain derived neurotrophic factor, plasma and mitochondrial DNA) and brain magnetic resonance imaging. In statistical analysis, we compared the differences with age matched controls or performed correlation analysis among the parameters Result: One hundred and seventeen patients with epilepsy completed the sleep quality questionnaires. The results showed that 20 percent of patients had day time sleepiness, while the sleep disorder was prolong sleep latency and impaired sleep efficiency. In epilepsy characteristics, patients with complex partial seizure, intractable seizure or with multi-pharmacy were related with poor sleep quality. A total of 34 patients completed the serological, neurobehavior and brain magnetic resonance analysis. The results showed that patients with temporal lobe epilepsy had higher heat shock protein 70 and S100£]protein levels, while those with attacks more than twice per month had significant higher heat shock protein 70, S100£]protein and neuron specific enolase levels. Compared with the matched controls, the regions showing atrophy included hippocampus and parahippocampus, putamen, thalamus and supplementary motor areas. In correlation study, only heat shock protein 70 showed an inverse correlation with hippocampal volume (R square = 0.22, p = 0.007) after controlling for the effect of age. Conclusion: The study suggested that epilepsy risk characteristics, serological biomarkers, brain atrophic regions were important factors for day time sleepiness, sleep disturbances and neurobehavior changes in patients with epilepsy.

In eukaryotic cells, most proteins in the cytosol and nucleus are degraded via the ubiquitin-proteasome pathway. Ubiquitin is best known for its role in targeting proteins for degradation by the proteasome. Ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) is found specifically in central and peripheral neurons, and is responsible for the removal of small peptide fragments from the ubiquitin chain and for co-translational processing of ubiquitin gene products to generate free monomeric ubiquitin. In response to extreme conditions, cells exhibit an up-regulation of heat shock protein (HSP) expression, which contributes to repair and protective mechanisms. Within the HSP family, HSP70 is the major inducible member that protects against cell death. Based on the pharmacologic property of organophosphates as an inhibitor of cholinesterase, it is generally contended that manifestations of organophosphate poisoning, including secretion and muscle fasciculation, stupor, cardiopulmonary collapse, respiratory failure, coma or death, result from accumulation of, and over-stimulation by acetylcholine at peripheral of central synapses. One approach in furthering our understanding on organophosphate poisoning is delineation of its potential protective mechanisms. In this regard, the information on the cellular and molecular mechanisms that underlie organophosphate poisoning has received attention. Our laboratory demonstrated previously that a crucial brain site via which mevinphos (Mev), an organophosphate insecticide of the P=O type, acts is the rostral ventrolateral medulla (RVLM), the medullary origin of premotor sympathetic neurons that are responsible for the maintenance of vasomotor tone. The phasic changes in cardiovascular events over the course of acute Mev intoxication also parallel fluctuations of the ¡§life-and-death¡¨ signals that emanate form the RVLM. Based on a rat model of organophosphate poisoning that provides continuous information on cellular and molecular mechanisms in the RVLM, the present study was undertaken to evaluate whether changes in protein level of UCH-L1 or HSP70 are associated with death arising from Mev intoxication. We also evaluated the efficacy of both of them in the neuroprotection against fatality during Mev intoxication. The first part of this study investigated whether UCH-L1 plays a neuroprotective role at the RVLM, where Mev acts to elicit cardiovascular toxicity. In Sprague-Dawley rats maintained under propofol anesthesia, Mev (960 &#x00B5;g/kg, i.v.) induced a parallel and progressive augmentation in UCH-L1 or ubiquitin expression at the ventrolateral medulla during the course of Mev intoxication. The increase in UCH-L1 level was significantly blunted on pretreatment with microinjection bilaterally into the RVLM of a transcription inhibitor, actinomycin D (5 nmol) or a translation inhibitor, cycloheximide (20 nmol). Compared to artificial cerebrospinal fluid (aCSF) or sense uch-L1 oligonucleotide (100 pmol) pretreatment, microinjection of an antisense uch-L1 oligonucleotide (100 pmol) bilaterally into the RVLM significantly increased mortality, reduced the duration of the phase I (¡§pro- life¡¨ phase), blunted the increase in ubiquitin expression in ventrolateral medulla, and augmented the induced hypotension in rats that received Mev. The second part of this study investigated whether HSP70 plays a neuroprotective role at the RVLM. Intravenous administration of Mev (960

Chaperonins (Hsp60 chaperones) comprise a class of oligomeric, high-molecular-weight chaperones that have the unique ability to fold some proteins that cannot be folded by simpler chaperone systems. The term &ldquo / thermosome&rdquo / is used for molecular chaperonins from Archaeal organisms since they accumulate to high levels upon heat-shock. In this study first time, we have cloned and sequenced two Hsp60 subunit genes (&amp / #945 / and &amp / #946 / ) from a thermoacidophilic archaeon Thermoplasma volcanium. For cloning we have followed a PCR based strategy. Amplification of Hsp60 &amp / #945 / gene from chromosomal DNA of T. volcanium yielded a product of 1939 bp amplicon and that of Hsp60 &amp / #946 / gene yielded a product of 1921 bp amplicon. After ligation of the PCR fragments to pDrive vector, recombinant plasmids were transferred into E. coli TG-1 competent cells and recombinant colonies were selected by blue/white screening. The cloning of two subunit genes were confirmed by restriction mapping and by sequencing. Both subunit genes were then subcloned to pUC18 vector consequtively to construct a co-expression vector. Both subunit genes were expressed under control of their own promoters leading to production of active Hsp60 chaperonin (thermosome). Chaperone activity of the recombinant thermosome was shown by using pig citrate synthase enzyme as substrate. Thermosome induced refolding was observed when renaturation was carried out at 50&deg / C for 2,5 h. Under this condition, citrate synthase activities associated with control and test were &amp / #61508 / mA412/min:19.0 and &amp / #61508 / mA412/min:24.0 respectively. Clustal W Version 1.82 was used for multiple sequence alignments of Hsp60 &amp / #61537 / and Hsp60 &amp / #61538 / proteins of T. volcanium and other Hsp60 proteins from various eukaryotes, bacteria and archaea. The highest sequence similarity was found between &amp / #945 / subunit proteins of T. volcanium and T. acidophilum (94%) and &amp / #946 / subunit proteins of T. volcanium and T. acidophilum (93%). Clusters of orthologous groups and conserved domain database searches revealed the phylogenetic relationships between Hsp60 &amp / #61537 / and Hsp60 &amp / #61538 / subunits of T. volcanium thermosome and other Hsp60 proteins from various eukaryotes, bacteria and archaea. Induction of both subunit genes under heat shock (65&deg / C, 70&deg / C and 75&deg / C for 2h) and under oxidative stress (imposed by 0,008 mM, 0,01 mM, 0,02 mM, 0,03 mM and 0,05 mM H2O2) conditions was studied by Real-Time PCR technique and amplified cDNA band density analysis.

In this study, possible involvement of the small heat shock proteins (sHsps) from a thermoacidophilic archaeon, Thermoplasma (Tp) volcanium in the stress response was investigated. Our results showed that heterologous, high level expression of TVN0775/sHsp gene in E.coli increased its thermotolerance at 53&deg / C for two hours. But, the second sHsp of the Tp. volcanium, TVN0984/sHsp was not effective in improvement of the thermal resistance of the mesophilic bacterium (i. e., E.coli). The expression of the TVN0775/sHsp and TVN0984/sHsp genes increased about 3 fold after heat-shock at 65&deg / C, as revealed by Real-Time PCR analysis. Although expression of the both genes was induced at 70&deg / C, TVN0984/sHsp gene expression was increased higher (about 5 fold) than that of the TVN0775/sHsp gene expression (about 1.5 fold). Tp. volcanium cells were exposed to high pH (pH: 3.5, pH: 4.0, pH: 4.5, pH: 5.0), and the change in the sHsp genes&rsquo / expression profile were analyzed. The results showed that TVN0775/sHsp gene expression was more sensitive to increased pH than TVN0984/sHsp gene expression. The TVN0775/sHsp gene transcription induced at most 2.5 fold at pH 4.0 and the gene expression either reduced or did not change at higher pH values (i.e., pH 4.5 and 5.0). On the other hand, TVN0984/sHsp gene expression did not change at pH 4.0 but significantly reduced at higher pH values. The effect of oxidative stress on the expression of TVN0775 and TVN0984 genes was investigated by treatment of Tp. volcanium cells with 0.01 mM, 0.02 mM, 0,03 mM and 0.05 mM H2O2. For both sHsp genes, transcription was induced at lower concentrations of H2O2 (0.01 mM and 0.02 mM). At higher concentrations of H2O2 expression of both genes&rsquo / transcription either did not changed or down regulated. Lastly, in this study we have purified the recombinant TVN0775/sHsp, as an Nterminal 6x his-tag fusion to homogeneity on Ni-NTA affinity column. Purified protein samples were used in the chaperone activity assays using bovine glutamate dehydrogenase enzyme (boGDH) as substrate. We have found that the recovery of glutamate dehydrogenase activity at 45&deg / C, 50&deg / C and 53&deg / C in the presence of the Tp. volcanium sHsps was higher than that of spontaneous refolding. Also, TVN0775/sHsp increased the recovery of the boGDH enzyme that was denatured at 2.5 M GdnHCl concentrations for 30 min.

(理学療法基礎系7, 第42回日本理学療法学術大会)