Heat shock factors and the control of the stress response

Cognitive impairment and neurogenotoxic effects in rats exposed to low-intensity microwave radiation

The health hazard of microwave radiation (MWR) has become a recent subject of interest as a result of the enormous increase in mobile phone usage. The present study aimed to investigate the effects of chronic low-intensity microwave exposure on cognitive function, heat shock protein 70 (HSP70), and DNA damage in rat brain. Experiments were performed on male Fischer rats exposed to MWR for 180 days at 3 different frequencies, namely, 900, 1800 MHz, and 2450 MHz. Animals were divided into 4 groups: group I: sham exposed; group II: exposed to MWR at 900 MHz, specific absorption rate (SAR) 5.953 × 10(-4) W/kg; group III: exposed to 1800 MHz, SAR 5.835 × 10(-4) W/kg; and group IV: exposed to 2450 MHz, SAR 6.672 × 10(-4) W/kg. All the rats were tested for cognitive function at the end of the exposure period and were subsequently sacrificed to collect brain. Level of HSP70 was estimated by enzyme-linked immunotarget assay and DNA damage was assessed using alkaline comet assay in all the groups. The results showed declined cognitive function, elevated HSP70 level, and DNA damage in the brain of microwave-exposed animals. The results indicated that, chronic low-intensity microwave exposure in the frequency range of 900 to 2450 MHz may cause hazardous effects on the brain.

Transcriptome analysis revealed changes of multiple genes involved in immunity in Cynoglossus semilaevis during Vibrio anguillarum infection

Half-smooth tongue sole (Cynoglossus semilaevis) is one of the most valuable marine aquatic species in Northern China. Given to the rapid development of aquaculture industry, the C. semilaevis was subjected to disease-causing bacteria Vibrio anguillarum. It therefore is indispensable and urgent to understand the mechanism of C. semilaevis host defense against V. anguillarum infection. In the present study, the extensively analysis at the transcriptome level for V. Anguillarum disease in tongue sole was carried out. In total, 94,716 high quality contigs were generated from 75,884,572 clean reads in three libraries (HOSG, NOSG, and CG). 22,746 unigenes were identified when compared with SwissProt, an NR protein database and NT nucleotide database. 954 genes exhibiting the differentially expression at least one pair of comparison in all three libraries were identified. GO enrichment for these genes revealed gene response to biotic stimulus, immune system regulation, and immune response and cytokine production. Further, the pathways such as complement and coagulation cascades and Vibrio cholerae infection pathways were enriched in defensing of pathogen. Besides, 13,428 SSRs and 118,239 SNPs were detected in tongue sole, providing further support for genetic variation and marker-assisted selection in future. In summary, this study identifies several putative immune pathways and candidate genes deserving further investigation in the context of development of therapeutic regimens and lays the foundation for selecting resistant lines of C. semilaevis against V. anguillarum.

Effects of fructooligosaccharide on immune response, antioxidant capability and HSP70 and HSP90 expressions of blunt snout bream (Megalobrama amblycephala) under high ammonia stress

This study aimed to determine the effects of fructooligosaccharide (FOS) on immune response, antioxidant capability and HSP70 and HSP90 mRNA expressions of blunt snout bream (Megalobrama amblycephala) under high ammonia stress. A total of 360 fish were randomly distributed into three groups (each with four replicates) and were fed three levels of FOS (0, 0.4 and 0.8 %) for 8 weeks. After the feeding trial, 24 fish per tank were exposed to ammonia at 10 mg L(-1). After stress, plasma cortisol and glucose levels of fish fed 0.4 % FOS were all significantly lower than that of the control group at 6 and 3 h, respectively. Plasma lysozyme and alternative complement pathway (ACH50) activities as well as nitrogen monoxide (NO) levels all increased significantly with the maximum levels being attained at 6, 6 and 3 h, respectively. Thereafter, these parameters all decreased significantly. In addition, fish fed 0.4 % FOS showed higher immune parameters under stress compared with that of control group. In addition, liver superoxide dismutase and catalase activities of fish fed 0.4 % FOS were both significantly higher than that of the control group before and after stress, while the opposite was true for malondialdehyde content. After stress, the expression of HSP70 and HSP90 of fish fed FOS was significantly higher than that of the control group at 6 and 12 h, respectively. After 12 h stress, the cumulative mortality of fish fed FOS was significantly lower than that of the control. The results indicated that the supplementation of 0.4 % FOS could increase the nonspecific immunity, antioxidant capacity and HSP70 and HSP90 expression of blunt snout bream and enhance its resistance to high ammonia stress.

Role of dietary pro-oxidants in the maintenance of health and resilience to oxidative stress

The average length of human life is increasing, but so does the incidence of age- and lifestyle-related diseases. Improving diet and lifestyle is a key strategy for lifelong health and underlying mechanisms may well include increasing resilience pathways. The purpose of this review is to highlight and evaluate novel mechanisms by which dietary pro-oxidants, including bioactive phytochemicals and fatty acids, increase reactive oxygen species (ROS) concentrations just enough to activate transcription factor activation of nuclear factor erythroid 2 related factor 2 (Nrf-2) and heat shock factor (HSF), leading to an increase in levels of antioxidant enzymes and heat shock proteins that protect against the damaging effects of ROS. An increasing number of in vivo studies have now shown that dietary pro-oxidant compounds can increase the production of such resilience products. In most studies, dietary pro-oxidants normalized levels of antioxidant enzymes that were decreased by a range of different challenges, rather than raising levels of resilience products per se. Also, it is important to consider that the antioxidant response can be different for different organs. For future studies, however, the measurement of resilience markers may significantly improve our ability to prove the efficacy by which dietary bioactives with pro-oxidant capacities improve lifelong health.

High-throughput screen of natural product extracts in a yeast model of polyglutamine proteotoxicity

Proteins with expanded polyglutamine (polyQ) segments cause a number of fatal neurodegenerative disorders, including Huntington's disease (HD). Previous high-throughput screens in cellular and biochemical models of HD have revealed compounds that mitigate polyQ aggregation and proteotoxicity, providing insight into the mechanisms of disease and leads for potential therapeutics. However, the structural diversity of natural products has not yet been fully mobilized toward these goals. Here, we have screened a collection of ~11 000 natural product extracts for the ability to recover the slow growth of ΔProQ103-expressing yeast cells in 384-well plates (Z' ~ 0.7, CV ~ 8%). This screen identified actinomycin D as a strong inhibitor of polyQ aggregation and proteotoxicity at nanomolar concentrations (~50-500 ng/mL). We found that a low dose of actinomycin D increased the levels of the heat-shock proteins Hsp104, Hsp70 and Hsp26 and enhanced binding of Hsp70 to the polyQ in yeast. Actinomycin also suppressed aggregation of polyQ in mammalian cells, suggesting a conserved mechanism. These results establish natural products as a rich source of compounds with interesting mechanisms of action against polyQ disorders.

Silver nanoparticles – wolves in sheep's clothing?

We review the cellular and molecular mechanisms behind silver nanoparticle toxicity and their intracellular fate. In addition, the role of silver ions in the toxicity of silver nanoparticles is discussed.

Smoking and rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease caused by both genetic and environmental factors. Smoking has been implicated as one of the most important extrinsic risk factors for its development and severity. Recent developments have shed light on the pathophysiology of RA in smokers, including oxidative stress, inflammation, autoantibody formation and epigenetic changes. The association of smoking and the development of RA have been demonstrated through epidemiologic studies, as well as through in vivo and animal models of RA. With increased use of biological agents in addition to standard disease-modifying antirheumatic drugs (DMARDs), there has been interest in how smoking affects drug response in RA treatment. Recent evidence suggests the response and drug survival in people treated with anti-tumour necrosis factor (anti-TNF) therapy is poorer in heavy smokers, and possible immunological mechanisms for this effect are presented in the current paper.

The identification of the first molluscan Akirin2 with immune defense function in the Hong Kong oyster Crassostrea hongkongensis

The Akirin protein is a nuclear factor in the innate immune system that is highly conserved from insects to mammals and plays key roles in diverse biological processes, including immunity, myogenesis, development and the cellular stress response. However, the function of Akirins in mollusk, the second most diverse group of animals, is still poorly understood. In this study, we report the discovery of an Akirin2 gene homolog (ChAkirin2) and its biological functions in the Hong Kong oyster Crassostrea hongkongensis. ChAkirin2 is 189 amino acids in length and shares significant homology with invertebrate homologs. Phylogenetic analysis results revealed that ChAkirin2 is clustered with invertebrate Akirin2s. A sequence analysis of the 5' flanking regions of ChAkirin2 indicated that it harbors several potential PAMP-activated transcription factor binding sites (TFB), including sites for NF-κB, C/EBPα, AP-1, SRF, Oct-1 and GATA-1. An RT-PCR analysis showed that ChAkirin2 mRNA was ubiquitously expressed in various tissues and at different embryonic and larval stages. Additionally, upon infection by pathogens (Vibrio alginolyticus, Staphylococcus haemolyticus and Saccharomyces cerevisiae) and pathogen-associated molecular patterns (PAMPs: LPS, PGN and polyI:C), the expression of ChAkirin2 was significantly up-regulated. Moreover, fluorescence microscopy observations show that ChAkirin2 is located in the nuclei of HeLa cells, and the overexpression of ChAkirin2 activated the transcriptional activities of the NF-κB reporter gene in HEK293T cells. Altogether, this report provided the first experimental demonstration that mollusks possess a functional Akirin2 that is involved in the innate defense and embryogenesis processes of the oyster.

Molecular cloning, characterization and expression analysis of HSP60, HSP70 and HSP90 in the golden apple snail, Pomacea canaliculata

The golden apple snail, Pomacea canaliculata, has strong tolerance to high temperature, facilitating its invasion in East and Southeast Asia. In the present study, three cDNAs encoding heat shock proteins (PocaHSP60, PocaHSP70, PocaHSP90) in P. canaliculata were cloned and characterized. The PocaHSP60 cDNA was 2447 bp, containing an ORF encoding a polypeptide of 574 amino acids. The PocaHSP70 cDNA was 2644 bp, containing an ORF encoding a polypeptide of 643 amino acids. The PocaHSP90 cDNA was 2546 bp, containing an ORF encoding a polypeptide of 726 amino acids. Genomic DNA analysis showed that PocaHSP60 had 11 introns in the coding region and PocaHSP90 had 7 introns but PocaHSP70 had no one. The expression changes of these three PocaHSPs in the gill, digestive gland, kidney and foot muscle of P. canaliculata exposed to high and low temperature were investigated. The results of quantitative PCR and western blotting showed that the expression level of PocaHSP90 was much higher than PocaHSP60 and PocaHSP70 at room temperature, and PocaHSP70 expression level was the lowest among them. Afterheat shock, PocaHSP70 expression increased rapidly, much more significantly than PocaHSP90 expression, and the effect of heat shock on the expression of PocaHSP70 and PocaHSP90 in the different tissues of P. canaliculata was not the same. Unlike PocaHSP70 and PocaHSP90, PocaHSP60 expression seemed not to be affected by heat shock, because its expression was moderately induced only in the foot muscle. However, cool shock had little effect on the expression change of above three PocaHSPs. These results indicated that HSPs might be related to the thermal resistance of P. canaliculata.

Gastroprotective activity of Annona muricata leaves against ethanol-induced gastric injury in rats via Hsp70/Bax involvement

The popular fruit tree of Annona muricata L. (Annonaceae), known as soursop and graviola, is a widely distributed plant in Central and South America and tropical countries. Leaves of A. muricata have been reported to possess antioxidant and anti-inflammatory activities. In this study, the gastroprotective effects of ethyl acetate extract of A. muricata leaves (EEAM) were investigated against ethanol-induced gastric injury models in rats. The acute toxicity test of EEAM in rats, carried out in two doses of 1 g/kg and 2 g/kg, showed the safety of this plant, even at the highest dose of 2 g/kg. The antiulcer study in rats (five groups, n=6) was performed with two doses of EEAM (200 mg/kg and 400 mg/kg) and with omeprazole (20 mg/kg), as a standard antiulcer drug. Gross and histological features showed the antiulcerogenic characterizations of EEAM. There was significant suppression on the ulcer lesion index of rats pretreated with EEAM, which was comparable to the omeprazole effect in the omeprazole control group. Oral administration of EEAM to rats caused a significant increase in the level of nitric oxide and antioxidant activities, including catalase, glutathione, and superoxide dismutase associated with attenuation in gastric acidity, and compensatory effect on the loss of gastric wall mucus. In addition, pretreatment of rats with EEAM caused significant reduction in the level of malondialdehyde, as a marker for oxidative stress, associated with an increase in prostaglandin E2 activity. Immunohistochemical staining also demonstrated that EEAM induced the downregulation of Bax and upregulation of Hsp70 proteins after pretreatment. Collectively, the present results suggest that EEAM has a promising antiulcer potential, which could be attributed to its suppressive effect against oxidative damage and preservative effect toward gastric wall mucus.

Effects of the human antiepileptic drug carbamazepine on the behavior, biomarkers, and heat shock proteins in the Asian clam Corbicula fluminea

Carbamazepine (CBZ), an anticonvulsant and mood-stabilizing pharmaceutical, is a widespread contaminant in aquatic environments. In this study, the effects of chronic exposure to environmentally relevant CBZ concentrations were investigated in freshwater clams Corbicula fluminea. Adult C. fluminea were exposed to 0.5, 5, and 50 μg/L of CBZ for 30 days, after which siphoning behavior (filtration rates), biomarker levels, and heat shock protein expression were measured. The filtration rates were significantly decreased (p<0.05) by 50 μg/L CBZ treatment, indicating a negative impact on C. fluminea health. Superoxide dismutase (SOD) and glutathione reductase (GR) activities were decreased, and catalase (CAT) activity and malondialdehyde (MDA) content were increased in the gills and digestive gland, suggesting that CBZ induced an oxidative effect. The levels of Hsp22, Hsp40, and Hsp70 mRNAs were also markedly induced after 5 or 50 μg/L CBZ treatment (p<0.05), whereas Hsp60 and Hsp90 mRNAs in gills and Hsp60 mRNA in digestive gland were significantly repressed (p<0.05). Finally, the expression of Hsp70 protein was significantly increased (p<0.05) by 5 and 50 μg/L exposure. In aggregate, these results confirm that environmentally relevant concentrations of CBZ can exert a negative effect on C. fluminea tissue at the molecular and protein level.

Non-invasive assessment of animal exercise stress: real-time PCR of GLUT4, COX2, SOD1 and HSP70 in avalanche military dog saliva

Exercise has been shown to increase mRNA expression of a growing number of genes. The aim of this study was to assess if mRNA expression of the metabolism- and oxidative stress-related genes GLUT4 (glucose transporter 4), COX2 (cyclooxygenase 2), SOD1 (superoxide dismutase 1) and HSP70 (heat shock protein 70) in saliva changes following acute exercise stress in dogs. For this purpose, 12 avalanche dogs of the Italian Military Force Guardia di Finanza were monitored during simulation of a search for a buried person in an artificial avalanche area. Rectal temperature (RT) and saliva samples were collected the day before the trial (T0), immediately after the descent from a helicopter at the onset of a simulated avalanche search and rescue operation (T1), after the discovery of the buried person (T2) and 2 h later (T3). Expressions of GLUT4, SOD1, COX2 and HSP70 were measured by real-time PCR. The simulated avalanche search and rescue operation was shown to exert a significant effect on RT, as well as on the expression of all metabolism- and oxidative stress-related genes investigated, which peaked at T2. The observed expression patterns indicate an acute exercise stress-induced upregulation, as confirmed by the reductions in expression at T3. Moreover, our findings indicate that saliva is useful for assessing metabolism- and oxidative stress-related genes without the need for restraint, which could affect working dog performance.

Heme oxygenase in neuroprotection: from mechanisms to therapeutic implications

Heme oxygenase (HO) was regarded as an enzyme to degrade heme in aging red blood cells; recent studies suggested HO might have other functions such as neuroprotection. HO degrades heme to produce carbon monoxide (CO), iron (Fe²⁺) and biliverdin, which is rapidly converted to bilirubin (BR). Three isoforms of HO were identified in the brain: inducible form (HO-1) and constitutive forms (HO-2 and HO-3). HO-1 and HO-2 may have different mechanisms to protect neurons from oxidative stress. HO-1 is normally barely detectable in the brain. HO-1 can be induced mainly in microglia and astrocytes by oxidative stimulus rapidly. HO-1 might function as an emerging molecule to protect neurons against acute insults mediated by facilitating iron efflux from cells under stress conditions. Up-regulation of HO-1 was also found in brain glial cells in the aging and neurodegenerative diseases. This may lead to iron deposition and oxidative mitochondrial injury. HO-1 may confer neuroprotection or neurotoxic effect because of the balance between beneficial and toxic effects of heme and heme products. Pharmacological modulation of HO-1 induction represents a therapeutic strategy for several nervous system disorders. HO-2 predominantly expressed in neurons. Bilirubin has been demonstrated to protect neurons from oxidative stress in vivo and in vitro. Bilirubin can be oxidized to biliverdin by scavenging peroxyl radicals. HO-2 could protect neurons through bilirubin pathway. HO-2 might also promote neuronal survival through the CO-cGMP-MAPK pathway. Biliverdin/bilirubin may be possible therapeutic candidates to treat nervous system disease related with oxidative damage.

Proteomic alteration of PK-15 cells after infection by porcine circovirus type 2

Porcine circovirus type 2 (PCV2) has been identified as the essential causal agent of post-weaning multisystemic wasting syndrome, which has spread worldwide. To discover cellular protein responses of PK-15 cells to PCV2 infection, two-dimensional liquid chromatography-tandem mass spectrometry (MS) coupled with isobaric tags for relative and absolute quantification (iTRAQ) labeling was employed to quantitatively identify the proteins that were differentially expressed in PK-15 from the PCV2-infected group compared to the uninfected control group. A total of 196 cellular proteins in PK-15 that were significantly altered at different time periods post-infection were identified. These differentially expressed proteins were related to the biological processes of binding, cell structure, signal transduction, cell adhesion, etc. and their interactions. Moreover, some of these proteins were further confirmed by Western blot. The high number of differentially expressed proteins identified should be very useful in elucidating the mechanism of replication and pathogenesis of PCV2 in the future.

Evaluation of heat-shock protein A2 (HSPA2) in male rats before and after varicocele induction

Varicocele is a major cause of infertility and may impair spermatogenesis. This study evaluated the molecular consequences of varicocele on the induction of heat-shock proteins, intracellular chaperones involved in stress responses, and of the ubiquitin-proteasome system, which is participates in the removal of defective sperm in the testis and epididymis. Wistar rats were randomly divided into three groups: surgically induced left varicocele, sham-operated, and untreated controls. Two months after surgery, we observed significantly reduced sperm parameters, DNA integrity, and protamine content in the sperm retrieved from the left epididymis compared to the right epididymis in the varicocele group, as well as compared to sperm retrieved from the left epididymis of the sham and control groups. According to Western blot analysis, we observed significantly higher HSPA2 expression in testicular tissue from the left testis compared to the right testis in the varicocele group or the left testis of the control group. Immunohistochemical analysis showed that expression of HSPA2 was higher in the round spermatid and sperm from the left varicocele compared to the control group. There was normally less HSPA2 expressed in the caput and corpus compared to the cauda of the epididymis in the control group, but this pattern was altered in the caput epididymis of the varicocele group. Levels of ubiquitination were also remarkably lower in the left testis of the varicocele group. Therefore, varicocele impacts expression of HSPA2 and ubiquitination.

Synthetic and bioinspired cage nanoparticles for drug delivery

Nanotechnology has the potential to revolutionize drug delivery, but still faces some limitations. One of the main issues regarding conventional nanoparticles is their poor drug-loading and their early burst release. Thus, to overcome these problems, researchers have taken advantage of the host–guest interactions that drive some assemblies to form cage molecules able to strongly entrap their cargo and design new nanocarriers called cage nanoparticles. These systems can be classified into two categories: bioinspired nanosystems such as virus-like particles, ferritin, small heat shock protein: and synthetic host–guest supramolecular systems that require engineering to actually form supramolecular nanoassemblies. This review will highlight the recent advances in cage nanoparticles for drug delivery with a particular focus on their biomedical applications.

Targeting heat shock proteins to modulate α-synuclein toxicity

Parkinson's disease is a slowly progressive neurodegenerative disorder typically characterized by the loss of dopaminergic neurons within the substantia nigra pars compacta, and the intraneuronal deposition of insoluble protein aggregates chiefly comprised of α-synuclein. Patients experience debilitating symptoms including bradykinesia, rigidity and postural instability. No curative treatment currently exists and therapeutic strategies are restricted to symptomatic treatment only. Over the past decade a class of molecular chaperones called the heat shock proteins has emerged as a potentially promising therapeutic target. Heat shock proteins aid in the folding and refolding of proteins, and target denatured proteins to degradation systems. By targeting heat shock proteins through various means including overexpression and pharmacological enhancement, researchers have shown that α-synuclein aggregation and its associated cytotoxicity can be therapeutically modulated in an array of cell and animal models. This review highlights the relevant progress in this field and discusses the relevance of heat shock proteins as therapeutic modulators of α-synuclein toxicity to the rapidly evolving understanding of Parkinson's disease pathogenesis.

Virus versus host plant microRNAs: who determines the outcome of the interaction?

Considering the importance of microRNAs (miRNAs) in the regulation of essential processes in plant pathogen interactions, it is not surprising that, while plant miRNA sequences counteract viral attack via antiviral RNA silencing, viruses in turn have developed antihost defense mechanisms blocking these RNA silencing pathways and establish a counter-defense. In the current study, computational and stem-loop Reverse Transcription – Polymerase Chain Reaction (RT-PCR) approaches were employed to a) predict and validate virus encoded mature miRNAs (miRs) in 39 DNA-A sequences of the bipartite genomes of African cassava mosaic virus (ACMV) and East African cassava mosaic virus-Uganda (EACMV-UG) isolates, b) determine whether virus encoded miRs/miRs* generated from the 5′/3′ harpin arms have the capacity to bind to genomic sequences of the host plants Jatropha or cassava and c) investigate whether plant encoded miR/miR* sequences have the potential to bind to the viral genomes. Different viral pre-miRNA hairpin sequences and viral miR/miR* length variants occurring as isomiRs were predicted in both viruses. These miRNAs were located in three Open Reading Frames (ORFs) and in the Intergenic Region (IR). Moreover, various target genes for miRNAs from both viruses were predicted and annotated in the host plant genomes indicating that they are involved in biotic response, metabolic pathways and transcription factors. Plant miRs/miRs* from conserved and highly expressed families were identified, which were shown to have potential targets in the genome of both begomoviruses, representing potential plant miRNAs mediating antiviral defense. This is the first assessment of predicted viral miRs/miRs* of ACMV and EACMV-UG and host plant miRNAs, providing a reference point for miRNA identification in pathogens and their hosts. These findings will improve the understanding of host- pathogen interaction pathways and the function of viral miRNAs in Euphorbiaceous crop plants.

Investigation into the potential for hypoxic interior of neoplasms to enhance HSPA expression in glioma

Production of heat shock protein 70 (HSP70/HSPA) is induced by a wide range of cellular stress conditions, such as cancer and hypoxia. This study investigated the level of HSPA gene expression in human cell lines exposed to hypoxic conditions. Three human glioma cell lines were selected for this study, each representing different types of glioma (astrocytoma, oligodendroglioma and glioblastoma), with a normal human astrocyte cell line used as a control. HSPA RNA transcripts and proteins were examined in these samples using qRT-PCR, immunofluorescence and flow cytometry techniques. The average HSPA mRNA copy numbers detected in three glioma cell lines were approximately sixfold higher than in a normal astrocyte cell line. The expression of HSPA was induced in normal cell lines immediately after exposure to hypoxia with 33% of cells exhibiting expression. However, the effects of hypoxia on gene expression were marginal in glioma cells, due to the already increased levels of HSPA with both pre- and post-hypoxia samples showing expression in approximately 90% of cells. These results show that whilst the stress caused by both cancer and hypoxia induce HSPA expression the underlying imprint of tumourgenesis leads to sustained expression.

Reliability of HSP70 (HSPA) expression as a prognostic marker in glioma

Production of heat shock protein 70 (HSP70/HSPA) is induced by a wide range of cellular stress conditions, such as cancer and hypoxia, with production also being linked to tumourigenesis. HSPA mRNA transcripts and proteins were examined in three human glioma cell lines, representing astrocytoma, oligodendroglioma and glioblastoma, plus 18 clinical brain tissue samples. GAPDH was used as a control gene throughout these studies and exhibited a consistent level of expression in a normal astrocyte cell line, tumourous cell lines and tissue samples. In contrast, the average HSPA mRNA copy numbers detected in glioblastoma tissue were between 1.8- and 8.8-fold higher than in lower grade glioma and control tissue, respectively, which is suggestive of a grade-related transcription profile. Similar patterns of grade-related expression were also observed in glioma cell lines. This study indicates for the first time that HSPA expression in glioma cells may possibly be grade related, and hence could have potential as a prognostic marker.

Differential HSP70 expression in Mytilus coruscus under various stressors

Heat shock proteins (HSPs) play crucial roles in protecting cells against environmental stresses, such as heat shock, heavy metals and pathogenic bacteria. Among the HSP family, the 70-kDa HSPs are most responsible for intracellular chaperone and extracellular immunoregulatory functions. The full-length HSP70 cDNA of Mytilus coruscus (designated as McHSP70, GenBank accession no. KF322135) was obtained, which was 2319 bp, including an ORF of 1965 bp to encode a polypeptide of 655 amino acid with predicted pI/MW5.29/71.38 kDa, a 81 bp-5'-UTR and a 270 bp-3'-UTR. The BLAST analysis and phylogenetic relationship strongly suggested that this amino acid sequence was a member of HSP70 family and highly homologous with Mytilus galloprovincialis (95%). Multiple sequence alignment revealed that McHSP70 and other known HSP70 were highly conserved, especially in the regions of HSP70 family signatures, the bipartite nuclear targeting sequence, ATP/GTP-Binding site motif and 'EEVD' motif. The mRNA of McHSP70 in hemolymph was constitutively expressed in all treatments including Vibrio challenge, thermal stress, metals (copper and cadmium) and 180 CST fuel exposure based on SYBR Green quantitative RT-PCR analysis. The temporal expression of HSP70 mRNA in hemolymph was significantly affected by Vibrio alginolyticus and Vibrio harveyi challenge. The maximum level appeared at 24h post-injection with 5.44-fold in V. alginolyticus and dropped back to the original level at 72 h post-injection. In V. harveyi infection the transcripts of McHSP70 was significantly induced to the highest at 2h after post-injection with 13.52-fold, then decreased until 36 h appearing another expression peak with 10.29-fold, and returned gradually to physiological level at the end of this experiment. In heat shock experiment the maximum expression appeared at 12h with 15-fold higher than that of blank mussels. Time-dependent mRNA expression pattern of McHSP70 was found in exposure to copper, cadmium and 180 CST fuel, but the highest expression and time were different in various treatments (copper of 9.41-fold at day 15, cadmium of 10.82-fold at day 10, and 180 CST fuel of 5.94-fold at day 25), and then dropped progressively. All these results indicated that HSP70 in marine bivalve had a significant role in mediating the environmental stress and immune response.

Heat Shock Proteins: Intestinal Gatekeepers that Are Influenced by Dietary Components and the Gut Microbiota

Trillions of microorganisms that inhabit the intestinal tract form a diverse and intricate ecosystem with a deeply embedded symbiotic relationship with their hosts. As more detailed information on gut microbiota complexity and functional diversity accumulates, we are learning more about how diet-microbiota interactions can influence the immune system within and outside the gut and host health in general. Heat shock proteins are a set of highly conserved proteins that are present in all types of cells, from microbes to mammals. These proteins carry out crucial intracellular housekeeping functions and unexpected extracellular immuno-regulatory features in order to maintain the mucosal barrier integrity and gut homeostasis. It is becoming evident that the enteric microbiota is one of the major determinants of heat shock protein production in intestinal epithelial cells. This review will focus on the interactions between diet, gut microbiota and their role for regulating heat shock protein production and, furthermore, how these interactions influence the immune system and the integrity of the mucosal barrier.

The master regulator of the cellular stress response (HSF1) is critical for orthopoxvirus infection

The genus Orthopoxviridae contains a diverse group of human pathogens including monkeypox, smallpox and vaccinia. These viruses are presumed to be less dependent on host functions than other DNA viruses because they have large genomes and replicate in the cytoplasm, but a detailed understanding of the host factors required by orthopoxviruses is lacking. To address this topic, we performed an unbiased, genome-wide pooled RNAi screen targeting over 17,000 human genes to identify the host factors that support orthopoxvirus infection. We used secondary and tertiary assays to validate our screen results. One of the strongest hits was heat shock factor 1 (HSF1), the ancient master regulator of the cytoprotective heat-shock response. In investigating the behavior of HSF1 during vaccinia infection, we found that HSF1 was phosphorylated, translocated to the nucleus, and increased transcription of HSF1 target genes. Activation of HSF1 was supportive for virus replication, as RNAi knockdown and HSF1 small molecule inhibition prevented orthopoxvirus infection. Consistent with its role as a transcriptional activator, inhibition of several HSF1 targets also blocked vaccinia virus replication. These data show that orthopoxviruses co-opt host transcriptional responses for their own benefit, thereby effectively extending their functional genome to include genes residing within the host DNA. The dependence on HSF1 and its chaperone network offers multiple opportunities for antiviral drug development.

Comparative analysis of αB-crystallin expression in heat-stressed myocardial cells in vivo and in vitro

Relationships between αB-crystallin expression patterns and pathological changes of myocardial cells after heat stress were examined in vitro and in vivo in this study using the H₉C₂ cell line and Sprague-Dawley rats, respectively. Histopathological lesions, characterized by acute degeneration, karyopyknosis and loss of a defined nucleus, became more severe in rat hearts over the course of heat stress treatment from 20 min to 100 min. The expression of αB-crystallin in rat hearts showed a significant decrease (P<0.05) throughout the heat stress treatment period, except at the 40 min time point. Likewise, decreased αB-crystallin expression was also observed in the H₉C₂ cell line exposed to a high temperature in vitro, although its expression recovered to normal levels at later time points (80 and 100 min) and the cellular damage was less severe. The results suggest that αB-crystallin is mobilized early after exposure to a high temperature to interact with damaged proteins but that the myocardial cells cannot produce sufficient αB-crystallin for protection against heat stress. Lower αB-crystallin expression levels were accompanied by obvious cell/tissue damage, suggesting that the abundance of this protein is associated with protective effects in myocardial cells in vitro and in vivo. Thus, αB-crystallin is a potential biomarker of heat stress.

Whey protein hydrolysate enhances HSP90 but does not alter HSP60 and HSP25 in skeletal muscle of rats

Whey protein hydrolysate (WPH) intake has shown to increase HSP70 expression. The aim of the present study was to investigate whether WPH intake would also influences HSP90, HSP60 and HSP25 expression, as well as associated parameters. Forty-eight male Wistar rats were divided into sedentary (unstressed) and exercised (stressed) groups, and were fed with three different sources of protein: whey protein (WP), whey protein hydrolysate (WPH) and casein (CAS) as a control, based on the AIN93G diet for 3 weeks. WPH intake increased HSP90 expression in both sedentary and exercised animals compared to WP or CAS, however no alteration was found from exercise or diet to HSP60 or HSP25. Co-chaperone Aha1 and p-HSF1 were also increased in the exercised animals fed with WPH in comparison with WP or CAS, consistent with enhanced HSP90 expression. VEGF and p-AKT were increased in the WPH exercised group. No alteration was found in BCKDH, PI3-Kinase (p85), GFAT, OGT or PGC for diet or exercise. The antioxidant system GPx, catalase and SOD showed different responses to diet and exercise. The data indicate that WPH intake enhanced factors related to cell survival, such as HSP90 and VEGF, but does not alter HSP60 or HSP25 in rat skeletal muscle.

Effects of Escherichia coli- and Staphylococcus aureus-induced mastitis in lactating cows on oocyte developmental competence

Mastitis is associated with decreased fertility in dairy cows. In the current study, we created an experimental model to simulate short-term mastitis by a single intramammary administration of Gram-negative endotoxin ofEscherichia coliorigin (G−), or Gram-positive toxin ofStaphylococcus aureusorigin (G+), to examine the effect of mastitis on oocyte developmental competence. Healthy Holstein cows were synchronized, and follicular fluid (FF) of cows treated with G+ or G− and of uninfected cows (controls) was aspirated from the preovulatory follicles by transvaginal ultrasound procedure. The aspirated FF was used as maturation medium forin vitroembryo production. The distribution of matured oocytes into different cortical granule classes and meiotic stages was affected by G− administration (P<0.05) but not by G+ administration. The proportion of oocytes that cleaved to two- and four-cell stage embryos (44 h postfertilization) was lower in both G+ and G− groups than in controls (P<0.05). Blastocyst formation rate (7–8 days postfertilization) was lower in the G− group (P<0.05) and numerically lower in the G+ group compared with their uninfected counterparts. The total cell number in blastocysts did not differ among groups; however, the apoptotic index was higher in the G+ group (P<0.05), but not in the G− group, relative to controls. Examining mRNA relative abundance in oocytes and early embryos revealed mastitis-induced alterations inPTGS2(COX2),POU5F1, andHSF1but not inSLC2A1(GLUT1) orGDF9. Results indicate a differential disruptive effect of mastitis induced by G− and G+ on oocyte developmental competence in association with alterations in maternal gene expression.

Age-dependent expression of stress and antimicrobial genes in the hemocytes and siphon tissue of the Antarctic bivalve, Laternula elliptica, exposed to injury and starvation

Increasing temperatures and glacier melting at the Western Antarctic Peninsula (WAP) are causing rapid changes in shallow coastal and shelf systems. Climate change-related rising water temperatures, enhanced ice scouring, as well as coastal sediment runoff, in combination with changing feeding conditions and microbial community composition, will affect all elements of the nearshore benthic ecosystem, a major component of which is the Antarctic soft-shelled clam Laternula elliptica. A 454-based RNA sequencing was carried out on tissues and hemocytes of L. elliptica, resulting in 42,525 contigs, of which 48 % was assigned putative functions. Changes in the expression of putative stress response genes were then investigated in hemocytes and siphon tissue of young and old animals subjected to starvation and injury experiments in order to investigate their response to sedimentation (food dilution and starvation) and iceberg scouring (injury). Analysis of antioxidant defense (Le-SOD and Le-catalase), wound repair (Le-TIMP and Le-chitinase), and stress and immune response (Le-HSP70, Le-actin, and Le-theromacin) genes revealed that most transcripts were more clearly affected by injury rather than starvation. The upregulation of these genes was particularly high in the hemocytes of young, fed individuals after acute injury. Only minor changes in expression were detected in young animals under the selected starvation conditions and in older individuals. The stress response of L. elliptica thus depends on the nature of the environmental cue and on age. This has consequences for future population predictions as the environmental changes at the WAP will differentially impact L. elliptica age classes and is bound to alter population structure.

A novel ortholog of serum response factor (SRF) with immune defense function identified in Crassostrea hongkongensis

Serum response factor (SRF) function is essential for transcriptional regulation of numerous growth-factor-inducible genes and triggers proliferation, differentiation and apoptosis of the cells. In this report, the first mollusk serum response factor like homolog gene (designated ChSRF) was identified and characterized from the Hong Kong oyster, Crassostrea hongkongensis. The full-length cDNA of ChSRF was 1716 bp in length and encodes a putative protein of 434 amino acids respectively, and shares the MADS domain at the N-terminal. ChSRF is ubiquitously expressed in various tissues, with the highest expression level observed in muscle. Temporal expression of ChSRF following microbe infection shows that the expression of ChSRF in hemocytes increases from 3 to 24 h post-challenge. As a target gene of SRF, β-actin demonstrates a similar gene expression mode in constitutive tissue and pathogen infection. Furthermore, some protein profiles of ChSRF was revealed, fluorescence microscopy results show that ChSRF located in the nuclei of HeLa cells and over-expression of ChSRF activated the transcriptional activities of MAPK signal pathway in HEK293T cells. These results indicate that ChSRF maybe play an important role in signal transduction in the immunity and development response of oysters. Furthermore, we found that ChSRF could regulate the expression of β-actin gene, which indicate that ChSRF is a muscle differentiation regulator in the oyster and it will help us to improve aquaculture production.

A proteomic study of plasma protein changes under extreme physical stress

The Spartathlon race (brisk walking a distance of 246km in less than 36h) was employed as a model of severe physical stress to investigate proteomic alterations in the plasma of athletes at the start (Athens) and finish (Sparta) of the race, as well as 48h after the race (Post). The athletes' plasma was analyzed by 2D gel electrophoresis (2-DE) and the differentially expressed proteins were identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS). The ProteoSeek™ Albumin/IgG removal kit and the ProteoMiner™ enrichment kit were utilized to detect medium- and low-abundance proteins, whose expression may be masked due to high-abundance proteins. Our results were confirmed by Western blot and biochemical analyses. Overall fifty-two proteins were differentially expressed between the starting point, the finishing line and two days after the end of the race. Of these, thirty proteins were involved in inflammation, while the rest concerned anti-oxidation, anti-coagulation and iron and vitamin D transport. These results indicate that prolonged physical stress affects circulating stress-related proteins, which might be employed as biomarkers of stress-related diseases.

BIOLOGICAL SIGNIFICANCE

The current study employed the Spartathlon, as a model of prolonged endurance exercise, to identify and isolate putative biomarkers of inflammation under extreme physical stress conditions. These protein quantitative variations may pave the way to exploration and understanding of stress-related physiological processes, the stress response itself and diseases whose onset appears to be linked to stress.

Populus euphratica: the transcriptomic response to drought stress

Populus euphratica Olivier is widely established in arid and semiarid regions but lags in the availability of transcriptomic resources in response to water deficiency. To investigate the mechanisms that allow P. euphratica to maintain growth in arid regions, the responses of the plant to soil water deficit were analyzed at a systems level using physiological and pyrosequencing approaches. We generated 218,601 and 287,120 reads from non-stressed control and drought-stressed P. euphratica leaves respectively, totaling over 200 million base pairs. After assembly, 24,013 transcripts were yielded with an average length of 1,128 bp. We determined 2,279 simple sequence repeats, which may have possible information for understanding drought adaption of woody plants. Stomatal closure was inhibited under moderate drought to maintain a relatively high rate of CO2 assimilation and water transportation, which was supposed to be important for P. euphratica to maintain normal growth and develop vigorous root systems in an adverse environment. This was accompanied by strong transcriptional remodeling of stress-perception, signaling and transcription regulation, photoprotective system, oxidative stress detoxification, and other stress responsive genes. In addition, genes involved in stomatal closure inhibition, ascorbate-glutathione pathway and ubiquitin-proteasome system that may specially modulate the drought stress responses of P. euphratica are highlighted. Our analysis provides a comprehensive picture of how P. euphratica responds to drought stress at physiological and transcriptome levels which may help to understand molecular mechanisms associated with drought response and could be useful for genetic engineering of woody plants.

Heat shock protein 70 expression and effect of combined transcatheter arterial embolization and radiofrequency ablation in the rabbit VX2 liver tumour model

AIM

To evaluate the effects of a combined therapy using transcatheter arterial embolization (TAE) and radiofrequency ablation (RFA) on heat shock protein 70 (HSP70) expression and treatment effects in a rabbit model of VX2 liver tumours.

MATERIALS AND METHODS

Tumour growth and necrosis rates were evaluated on day 7. Five rabbits were assigned to each group and were killed on days 1, 3, and 7 after treatment. HSP70 expression was detected and quantified by immunohistochemistry, Western blot, and reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

Tumour growth rate was significantly decreased and the necrosis rate increased in the TAE + RFA group on day 7 compared with the other groups. HSP70 expression in the TAE group peaked on day 1 and bottomed on days 3 and 7. HSP70 expression in the TAE group was significantly greater than in the control group on days 1, 3, and 7. HSP70 expression was increased on day 1, peaked on day 3, and dropped on day 7 in the RFA and TAE + RFA groups. In the TAE + RFA group, HSP70 expression was significantly greater than in the other groups on days 1, 3, and 7. HSP70 expression in Western blot analysis and HSP70 mRNA peaked on day 3 and dropped on day 7 in the TAE, RFA, and TAE + RFA groups.

CONCLUSIONS

HSP70 over-expression in residual tumours after TAE + RFA could be attributed to the additive effects of hypoxia and hyperpyrexia generated by TAE combined with RFA.

Pattern of heat shock factor and heat shock protein expression in lymphocytes of bipolar patients: increased HSP70-glucocorticoid receptor heterocomplex

Bipolar disorder (BD), a stress-related disease, is characterized by altered glucocorticoid receptor (GR) signalling. Stress response includes activation of heat shock factor (HSF) and subsequent heat shock protein (HSP) synthesis which regulate GR folding and function. The objective of this study was to investigate the possible role of HSFs, HSPs and their interaction with GR in BD. We applied immunoprecipitation, SDS-PAGE/Western blot analysis and electrophoretic mobility shift assay (EMSA) in lymphocytes (whole cell or nuclear extracts) from BD patients and healthy subjects and determined the HSPs (HSP90 and HSP70), the heterocomplexes HSP90-GR and HSP70-GR, the HSFs (HSF1 and HSF4) as well as the HSF-DNA binding. The HSP70-GR heterocomplex was elevated (p < 0.05) in BD patients vs healthy subjects, and nuclear HSP70 was reduced (p ≤ 0.01) in bipolar manic patients. Protein levels of HSF1, HSF4, HSP90, HSP90-GR heterocomplex, and HSF-DNA binding remained unaltered in BD patients vs healthy subjects. The corresponding effect sizes (ES) indicated a large ES for HSP70-GR, HSP70, HSF-DNA binding and HSF4, and a medium ES for HSP90, HSF1 and HSP90-GR between healthy subjects and bipolar patients. Significant correlations among HSFs, HSPs, GR and HSP70-GR heterocomplex were observed in healthy subjects, which were abrogated in bipolar patients. The higher interaction between GR and HSP70 and the disturbances in the relations among heat shock response parameters and GR as observed in our BD patients may provide novel insights into the contribution of these factors in BD aetiopathogenesis.

Heat shock transcription factor 1-deficiency attenuates overloading-associated hypertrophy of mouse soleus muscle

Hypertrophic stimuli, such as mechanical stress and overloading, induce stress response, which is mediated by heat shock transcription factor 1 (HSF1), and up-regulate heat shock proteins (HSPs) in mammalian skeletal muscles. Therefore, HSF1-associated stress response may play a key role in loading-associated skeletal muscle hypertrophy. The purpose of this study was to investigate the effects of HSF1-deficiency on skeletal muscle hypertrophy caused by overloading. Functional overloading on the left soleus was performed by cutting the distal tendons of gastrocnemius and plantaris muscles for 4 weeks. The right muscle served as the control. Soleus muscles from both hindlimbs were dissected 2 and 4 weeks after the operation. Hypertrophy of soleus muscle in HSF1-null mice was partially inhibited, compared with that in wild-type (C57BL/6J) mice. Absence of HSF1 partially attenuated the increase of muscle wet weight and fiber cross-sectional area of overloaded soleus muscle. Population of Pax7-positive muscle satellite cells in HSF1-null mice was significantly less than that in wild-type mice following 2 weeks of overloading (p<0.05). Significant up-regulations of interleukin (IL)-1β and tumor necrosis factor mRNAs were observed in HSF1-null, but not in wild-type, mice following 2 weeks of overloading. Overloading-related increases of IL-6 and AFT3 mRNA expressions seen after 2 weeks of overloading tended to decrease after 4 weeks in both types of mice. In HSF1-null mice, however, the significant overloading-related increase in the expression of IL-6, not ATF3, mRNA was noted even at 4th week. Inhibition of muscle hypertrophy might be attributed to the greater and prolonged enhancement of IL-6 expression. HSF1 and/or HSF1-mediated stress response may, in part, play a key role in loading-induced skeletal muscle hypertrophy.

Hsp70 positively regulates porcine circovirus type 2 replication in vitro

The Hsp70 chaperone plays a central role in multiple processes within cells. Porcine circovirus type 2 (PCV2) is the essential causal agent of post-weaning multisystemic wasting syndrome (PMWS), which has spread worldwide. But the mechanism of PCV2 replication remains poorly understood. In this study, we firstly found the positive effect of heat stress on the replication of PCV2 in the continuous porcine monocytic cell line 3D4/31. Downregulation of Hsp70 by the specific chaperone inhibitor Quercetin or RNA interference and upregulation of Hsp70 by expression from a recombinant adenovirus showed that Hsp70 enhanced PCV2 genome replication and virion production. A specific interaction between Hsp70 and PCV2 Cap was confirmed by colocalization by confocal microscopy and co-immunoprecipitation. Furthermore, the NF-κB pathway was activated and caspase-3 activity was reduced when Hsp70 was overexpressed in PCV2-infected 3D4/31 cells. These data suggested that Hsp70 positively regulated PCV2 replication, which being helpful for understanding the molecular mechanism of PCV2 infection.

Gastroprotection studies of Schiff base zinc (II) derivative complex against acute superficial hemorrhagic mucosal lesions in rats

Background

The study was carried out to assess the gastroprotective effect of the zinc (II) complex against ethanol-induced acute hemorrhagic lesions in rats.

Methodology/Principal Finding

The animals received their respective pre-treatments dissolved in tween 20 (5% v/v), orally. Ethanol (95% v/v) was orally administrated to induce superficial hemorrhagic mucosal lesions. Omeprazole (5.790×10⁻⁵ M/kg) was used as a reference medicine. The pre-treatment with the zinc (II) complex (2.181×10⁻⁵ and 4.362×10⁻⁵ M/kg) protected the gastric mucosa similar to the reference control. They significantly increased the activity levels of nitric oxide, catalase, superoxide dismutase, glutathione and prostaglandin E2, and decreased the level of malondialdehyde. The histology assessments confirmed the protection through remarkable reduction of mucosal lesions and increased the production of gastric mucosa. Immunohistochemistry and western blot analysis indicated that the complex might induced Hsp70 up-regulation and Bax down-regulation. The complex moderately increased the gastroprotectiveness in fine fettle. The acute toxicity approved the non-toxic characteristic of the complex (<87.241×10⁻⁵ M/kg).

Conclusion/Significance

The gastroprotective effect of the zinc (II) complex was mainly through its antioxidant activity, enzymatic stimulation of prostaglandins E2, and up-regulation of Hsp70. The gastric wall mucus was also a remarkable protective mechanism.

Hyperglycaemia and oxidative stress upregulate HSP60 & HSP70 expression in HeLa cells

Heat Shock Proteins 60 & 70 (HSP60 & HSP70) are intracellular protein that has been shown to be present at elevated levels in systemic circulation in Type 2 Diabetes mellitus (T2DM) patients. Conditions that lead to its secretion, and the mechanism of its translocation from cells, have not yet been defined. The aim of this study was to determine if specific cell stressors associated with T2DM, namely hyperglycaemia and oxidative stress, result in the upregulation of HSP60 in human cells in vitro. Human HeLa cells were grown in media supplemented with 100 mM glucose, 200 μM hydrogen peroxide (H₂O₂), and 50 μM sodium azide. Initially, the effect of these treatments on cell growth rate was examined, with each treatment significantly inhibiting growth rate. LDH and MTT assays were also used to successfully demonstrate that these treatments do not significantly increase cell lysis, but do significantly impair mitochondrial dehydrogenase activity. To confirm this mitochondria specific form of inhibition, DCFDA assay were used to investigate any increases in intracellular reactive oxygen species (ROS) generation. All three treatments resulted in significantly increased ROS generation, with greater ROS production occurring with a greater exposure time. Interestingly, when the protein levels of HSP60 and HSP70 were measured after 3 and 7 days of exposure of the HeLa cells to 100 mM glucose, 200 μM H₂O₂, and 50 μM sodium azide significant induction of these two molecular stress proteins were observed ranging from 2.43-5.08 fold compared to untreated control cells.

Regeneration of injured skeletal muscle in heat shock transcription factor 1-null mice

The purpose of this study was to investigate a role of heat shock transcription factor 1 (HSF1)-mediated stress response during regeneration of injured soleus muscle by using HSF1-null mice. Cardiotoxin (CTX) was injected into the left muscle of male HSF1-null and wild-type mice under anesthesia with intraperitoneal injection of pentobarbital sodium. Injection of physiological saline was also performed into the right muscle. Soleus muscles were dissected bilaterally 2 and 4 weeks after the injection. The relative weight and fiber cross-sectional area in CTX-injected muscles of HSF1-null, not of wild-type, mice were less than controls with injection of physiological saline 4 weeks after the injury, indicating a slower regeneration. Injury-related increase of Pax7-positive muscle satellite cells in HSF1-null mice was inhibited versus wild-type mice. HSF1-deficiency generally caused decreases in the basal expression levels of heat shock proteins (HSPs). But the mRNA expression levels of HSP25 and HSP90α in HSF1-null mice were enhanced in response to CTX-injection, compared with wild-type mice. Significant up-regulations of proinflammatory cytokines, such as interleukin (IL) -6, IL-1β, and tumor necrosis factor mRNAs, with greater magnitude than in wild-type mice were observed in HSF1-deficient mouse muscle. HSF1 and/or HSF1-mediated stress response may play a key role in the regenerating process of injured skeletal muscle. HSF1 deficiency may depress the regenerating process of injured skeletal muscle via the partial depression of increase in Pax7-positive satellite cells. HSF1-deficiency-associated partial depression of skeletal muscle regeneration might also be attributed to up-regulation of proinflammatory cytokines.

Localization and expression of Hsp27 and αB-crystallin in rat primary myocardial cells during heat stress in vitro

Neonatal rat primary myocardial cells were subjected to heat stress in vitro, as a model for investigating the distribution and expression of Hsp27 and αB-crystallin. After exposure to heat stress at 42°C for different durations, the activities of enzymes expressed during cell damage increased in the supernatant of the heat-stressed myocardial cells from 10 min, and the pathological lesions were characterized by karyopyknosis and acute degeneration. Thus, cell damage was induced at the onset of heat stress. Immunofluorescence analysis showed stronger positive signals for both Hsp27 and αB-crystallin from 10 min to 240 min of exposure compared to the control cells. According to the Western blotting results, during the 480 min of heat stress, no significant variation was found in Hsp27 and αB-crystallin expression; however, significant differences were found in the induction of their corresponding mRNAs. The expression of these small heat shock proteins (sHsps) was probably delayed or overtaxed due to the rapid consumption of sHsps in myocardial cells at the onset of heat stress. Our findings indicate that Hsp27 and αB-crystallin do play a role in the response of cardiac cells to heat stress, but the details of their function remain to be investigated.

Key role of lipids in heat stress management

Heat stress is a common and, therefore, an important environmental impact on cells and organisms. While much attention has been paid to severe heat stress, moderate temperature elevations are also important. Here we discuss temperature sensing and how responses to heat stress are not necessarily dependent on denatured proteins. Indeed, it is clear that membrane lipids have a pivotal function. Details of membrane lipid changes and the associated production of signalling metabolites are described and suggestions made as to how the interconnected signalling network could be modified for helpful intervention in disease.

The characteristics of the expression of heat shock proteins and COX-2 in the liver of hamsters infected with Clonorchis sinensis, and the change of endocrine hormones and cytokines

The liver fluke Clonorchis sinensis (Digenea) is a high-risk parasite that causes serious diseases such as cirrhosis, carcinogenic liver damage and clonorchiasis in East Asia. This study was conducted to evaluate the relationship between stress/endocrine hormones and inflammation induced by infection as well as the expression of heat shock proteins (hsp-27, hsp-90), cox-2 and cytokines in the livers of hamsters infected with C. sinensis. The average body weight of infected hamsters decreased up to 25% compared with that of the control group, and bile duct hyperplasia with inflammation, liver fibrosis and hepatic necrosis were observed in C. sinensis-infected livers. The expression of hsp-27, hsp-90, and cox-2 was significantly increased in the livers of C. sinensis-infected hamsters compared with the control group. Moreover, the expression levels of inflammatory cytokines (IL-1beta, IL-2, TGF-beta2 and IFN-alpha1) were markedly increased in the livers of the infected group compared with those of the control group. Consistently, plasma IL-3 and IL-6 levels gradually increased during the infection period, and the concentration levels of testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), corticosterone, and adrenocorticotropic hormone (ACTH) in C. sinensis-infected hamsters increased over 25%, compared with those of the uninfected normal group. These results demonstrate that C. sinensis infection may increase the expression of hsp27, hsp90 and cox-2 as well as it may cause periductal fibrosis, chronic inflammation and hepatic necrosis in the liver. Furthermore, the results indicate that C. sinensis infection induces not only stress-induced hormone imbalance but also the sustained secretion of inflammatory cytokines through chronic stress/stimuli.