Molecular cloning and characterization of porcine cDNA encoding a 90-kDa heat shock protein and its expression following hyperthermia

Genome-wide association study reveals novel loci for litter size and its variability in a Large White pig population

Background

In many traits, not only individual trait levels are under genetic control, but also the variation around that level. In other words, genotypes do not only differ in mean, but also in (residual) variation around the genotypic mean. New statistical methods facilitate gaining knowledge on the genetic architecture of complex traits such as phenotypic variability. Here we study litter size (total number born) and its variation in a Large White pig population using a Double Hierarchical Generalized Linear model, and perform a genome-wide association study using a Bayesian method.

Results

In total, 10 significant single nucleotide polymorphisms (SNPs) were detected for total number born (TNB) and 9 SNPs for variability of TNB (varTNB). Those SNPs explained 0.83 % of genetic variance in TNB and 1.44 % in varTNB. The most significant SNP for TNB was detected on Sus scrofa chromosome (SSC) 11. A possible candidate gene for TNB is ENOX1, which is involved in cell growth and survival. On SSC7, two possible candidate genes for varTNB are located. The first gene is coding a swine heat shock protein 90 (HSPCB = Hsp90), which is a well-studied gene stabilizing morphological traits in Drosophila and Arabidopsis. The second gene is VEGFA, which is activated in angiogenesis and vasculogenesis in the fetus. Furthermore, the genetic correlation between additive genetic effects on TNB and on its variation was 0.49. This indicates that the current selection to increase TNB will also increase the varTNB.

Conclusions

To the best of our knowledge, this is the first study reporting SNPs associated with variation of a trait in pigs. Detected genomic regions associated with varTNB can be used in genomic selection to decrease varTNB, which is highly desirable to avoid very small or very large litters in pigs. However, the percentage of variance explained by those regions was small. The SNPs detected in this study can be used as indication for regions in the Sus scrofa genome involved in maintaining low variability of litter size, but further studies are needed to identify the causative loci.

Effects of chronic heat stress on the expressions of heat shock proteins 60, 70, 90, A2, and HSC70 in the rabbit testis

Few studies have focused on the expression of heat shock proteins (HSPs) after chronic heat stress. The objective of this study was to investigate the effect of chronic high temperature-humidity index treatment on the expressions of HSP60, HSP70, HSP90, HSPA2 and HSC70, in the Rex rabbit testis and the expressions of these proteins after recovery from the chronic heat shock. Thirty mature male rabbits of the same age were randomly divided into three groups: control, heat stress, and recovery. The western blot results showed that the expressional levels of HSP60, HSP90, and HSC70 increased significantly and HSPA2 was elevated slightly after a 9-week heat treatment. HSP70 was absent in the control testis and had a high level of expression after heat stress. All of these proteins partially reverted back to normal levels after a 9-week recovery. The immunohistochemical results indicated that the expression patterns of HSP60, HSP90, HSPA2, and HSC70 did not change.

Effect of heat challenge on peripheral blood mononuclear cell viability: comparison of a tropical and temperate pig breed

We evaluated the effect of heat challenge on cell viability, concanavalin A-induced proliferation and heat shock protein (HSPs) mRNA expression in peripheral mononuclear blood cells (PBMC) isolated from Creole (CR) and Large White (LW) pigs. The PBMCs were cultured for 9 h at 37 °C before being subjected to heat challenge: (1) at 42 °C or 45 °C for 2, 4, 6 and 9 h to monitor cell viability;(2) at 45 °C for 2 and 9 h followed by stimulation for 24 h at 37 °C with concanavalin A to evaluate mitogen-induced proliferation; and (3) at 45 °C for 3, 6 and 9 h to measure induction of HSP70.2 and HSP90 mRNA. Cell viability was affected by breed and temperature (P < 0.01), and the viability decrease caused by heat challenge was greater for LW than CR pigs. For mitogen-stimulated PBMCs, incubation at 45 °C reduced lymphoblastogenesis equally in both breeds (P < 0.01). Although heat challenge for 3 and 6 h at 45°C induced expression of HSP70.2 and HSP90 mRNA, no breed difference was observed. In conclusion, differences in heat resistance between these two breeds at the whole organism level are reflected at the cellular level. Neither HSP70.2 nor HSP90 mRNA expression levels explain this effect.

Heat-shock proteins in cardiovascular disease

Heat-shock proteins (HSPs) belong to a group of highly conserved families of proteins expressed by all cells and organisms and their expression may be constitutive or inducible. They are generally considered as protective molecules against different types of stress and have numerous intracellular functions. Secretion or release of HSPs has also been described, and potential roles for extracellular HSPs reported. HSP expression is modulated by different stimuli involved in all steps of atherogenesis including oxidative stress, proteolytic aggression, or inflammation. Also, antibodies to HSPs may be used to monitor the response to different types of stress able to induce changes in HSP levels. In the present review, we will focus on the potential implication of HSPs in atherogenesis and discuss the limitations to the use of HSPs and anti-HSPs as biomarkers of atherothrombosis. HSPs could also be considered as potential therapeutic targets to reinforce vascular defenses and delay or avoid clinical complications associated with atherothrombosis.

Identification of two hsp90 genes from the marine crab, Portunus trituberculatus and their specific expression profiles under different environmental conditions

Hsp90, a molecular chaperone, was generally thought to be a unique cytoplasmic form in invertebrates, playing important roles in multiple cellular stress responses. Now, two cytoplasmic Hsp90 cDNAs (ptHSP90-1 and ptHSP90-2 genes) were isolated from an invertebrate - crab Portunus trituberculatus. Main features, sequence identities and phylogenetic analysis with other species were described. Expression profiles in tissues and under stressful conditions were analyzed using semi-quantitative RT-PCR method. ptHSP90-1 and ptHSP90-2 were constitutively expressed with higher transcript levels in ovary and muscle, respectively. A cold treatment rapidly activated both ptHSP90s transcription in hepatopancreas and gill, but caused the ptHSP90-2 mRNA decrease in muscle and ovary. Under heat treatment ptHSP90-1 mRNA was accumulated in hepatopancreas and muscle (but down-regulated in ovary), while ptHSP90-2's transcription tendency in each tissue was the same as that in cold shock. Moreover, the transcriptional levels of both ptHSP90 genes under Cu(2+) stress were evaluated. This crab exposed to the low and high salinity exhibited either lower expression levels of both ptHSP90s or no changes in four tissues except the up-regulation of ptHSP90-2 transcription in hepatopancreas. These results suggested there were at least two Hsp90s in P. trituberculatus, which played differing roles in physiological and stressful conditions.

Do sauna therapy and exercise act by raising the availability of tetrahydrobiopterin?

Sauna therapy has been used to treat a number of different diseases known or thought to have a tetrahydrobiopterin (BH4) deficiency. It has been interpreted to act in multiple chemical sensitivity by increasing chemical detoxification and excretion but there is no evidence that this is its main mode of action. Sauna therapy may act to increase BH4 availability via two distinct pathways. Increased blood flow in heated surface tissues leads to increased vascular shear stress, inducing increased activity of GTP cyclohydrolase I (GTPCH-I) in those vascular tissues which will lead to increasing BH4 synthesis. A second mechanism involves the heat shock protein Hsp90, which is induced by even modest heating of mammalian tissues. Sauna heating of these surface tissues may act via Hsp90, which interacts with the GTPCH-I complex and is reported to produce increased GTPCH-I activity by lowering its degradation. The increased consequent availability of BH4 may lead to lowered nitric oxide synthase uncoupling, such as has been reported for the eNOS enzyme. Increased BH4 synthesis in surface tissues of the body will produce increased circulating BH4 which will feed BH4 to other body tissues that may have been BH4 deficient. Similar mechanisms may act in vigorous exercise due to the increased blood shear stresses and possibly also heating of the exercising tissues and heart. There is a large and rapidly increasing number of diseases that are associated with BH4 depletion and these may be candidates for sauna therapy. Such diseases as hypertension, vascular endothelial dysfunction, multiple chemical sensitivity and heart failure are thought to be helped by sauna therapy and chronic fatigue syndrome and fibromyalgia may also be helped and there are others that may be good candidates for sauna therapy.

Molecular cloning and expression analysis of a heat shock protein (Hsp90) gene from black tiger shrimp (Penaeus monodon)

The techniques of homology cloning and anchored PCR were used to clone the Hsp90 gene from black tiger shrimp. The full length cDNA of black tiger shrimp Hsp90 (btsHsp90) contained a 5' untranslated region (UTR) of 72 bp, an ORF (open reading frame) of 2160 bp encoding a polypeptide of 720 amino acids with an estimated molecular mass of 83-kDa and a 3' UTR of 288 bp. The sequence of the coding region showed 90 and 84% homology with that of the Chiromantes haematocheir and Homo sapiens, respectively. Conserved signature sequences of Hsp90 gene family were found in the btsHsp90 deduced amino acid sequence. The temporal expressions of Hsp90 gene were constitutively in the black tiger shrimp tissues including liver, ovary, muscle, brain stomach, and heart, and their levels were markedly enhanced after 30-min heat treatment at 37 degrees C. In ovarian maturation stages, the expression of btsHsp90 was strongest in the second stage, weaker in the fourth and first stage.

Developmental changes of heat-shock proteins in porcine testis by a proteomic analysis

Heat-shock proteins (HSPs) are important in spermatogenesis. This study investigated developmental changes in the expression of major HSPs in porcine testis. The testis from five immature (mean age 2.9+/-0.1 months) and five mature boars (35.7+/-14.0 months) were examined. Two-dimensional polyacrylamide gel electrophoresis was conducted and proteins were identified by Western blotting and/or matrix-assisted laser desorption/ionization mass spectrometry. Moreover, the 90, 70, and 60 kDa HSPs, 70 kDa heat-shock cognate protein (HSC 70), tubulin, and actin were quantified on two-dimensional gels. Protein spots were quantified by densitometry, combined with a computer-assisted image analysis system. Immunohistochemistry was performed to analyze the expression pattern of major HSPs and beta-tubulin in testis. One isoform of HSP 90 (HSP 90 alpha), two isoforms of HSC 70 (HSC 70a and HSC 70c), one isoform of HSP70 (HSP 70e), and tubulin increased after sexual maturation (P<0.05). A testis-specific HSP70 (P70t) was markedly increased in the testes of sexually mature boars. Meanwhile, levels of actin and some isoforms of HSPs including 60 kDa HSP remained similar in both groups. These observations were further confirmed by immunohistochemistry; therefore, the upregulation of protein expression in the adult testis could be attributed to a higher level of protein expression and the number of cells that were HSPs-positive already resided in the immature testis. The differential expression of major HSPs suggested that they may be important in porcine spermatogenesis.

Identification of the pentapeptide constituting a dominant epitope common to all eukaryotic heat shock protein 90 molecular chaperones

We previously reported that, in human heat shock protein (Hsp) 90 (hHsp90), there are 4 highly immunogenic sites, designated sites Ia, Ib, Ic, and II. This study was performed to further characterize their epitopes and to identify the epitope that is potentially common to all members of the Hsp90 family. Panning of a bacterial library carrying randomized dodecapeptides revealed that Glu251-Ser-X-Asp254 constituted site Ia and Pro295-Ile-Trp-Thr-Arg299, site Ic. Site II (Asp701-Pro717) was composed of several epitopes. When 19 anti-hHsp90 monoclonal antibodies (mAbs) were subjected to immunoblotting against recombinant forms of 7 Hsp90-family members, 2 mAbs (K41110 and K41116C) that recognized site Ic bound to yeast Hsp90 with affinity identical to that for hHsp90, and 1 mAb (K3729) that recognized Glu222-Ala23, of hHsp90beta could bind to human 94-kDa glucose-regulated protein (Grp94), an endoplasmic reticulum paralog of Hsp90. Among the 5 amino acids constituting site Ic, Trp297 and Pro295 were essential for recognition by all anti-site-Ic mAbs, and Arg299 was important for most of them. The necessity of Ile296, Thr298, and Arg299, which are replaced by Leu, Met/Leu, and Lys, respectively, in some eukaryotic Hsp90, was dependent on the mAbs, and K41110 and K41116C could react with Hsp90s carrying these substitutions. From these data taken together, we propose that the pentapeptide Pro295-Ile-Trp-Thr-Arg299 of hHsp90 functions as an immunodominant epitope common to all eukaryotic Hsp90.

Geldanamycin inhibits trichostatin A-induced cell death and histone H4 hyperacetylation in COS-7 cells

As widely believed treating cells with trichostatin A (TSA), an inhibitor of histone deacetylase, results in histone H4 hyperacetylation and cell cycle arrest. This compound is often compared with other potential anticancer drugs in cell cycle, proliferation and differentiation research. Furthermore, geldanamycin (GA), a 90-kDa heat shock protein (HSP90) specific inhibitor, is a well-known potential anticancer agent. This study examines whether GA can affect the cellular functions induced by TSA. When using TSA treatment, although caused COS-7 cell death, pretreatment of 0.5 microg/ml GA for 30 min and an addition of 50 ng/ml TSA (GA + TSA) apparently averted cell death. Our results indicated that the cell survival rate was only approximately 20% when prolonged treatment was undertaken with 50 ng/ml TSA (TSA) alone for 24 h. In contrast, the cell survival rate was enhanced by two folds when treating with GA + TSA. Furthermore, DNA fragmentation assay revealed that fragmented DNA was produced 8 h after prolonged treatment with TSA alone. Within 16 h, the apoptotic percentages of TSA-treated cells were between 15-25%. In contrast, the other treatments did not exceed 6%. Furthermore, GA inhibited TSA-induced histone H4 hyperacetylation. Western blotting analysis further demonstrated that the HSP70 levels did not significantly increase in TSA-treated cells. However, the accumulated 70-kDa heat shock protein (HSP70) markedly increased up to 2 to 3 folds at 8 h in GA- and GA + TSA-treated cells, and the maximum amount up to 5 to 7 folds at 20 h. Conversely, HSP90 did not markedly increase in all treatments. Based on the results in this study, we suggest that apoptosis induced by TSA can be prevented by GA-induced increment of heat shock proteins, particularly HSP70.

Purification and characterization of porcine testis 90-kDa heat shock protein (HSP90) as a substrate for various protein kinases

We purified a large quantity of HSP90 from porcine testis by hydroxylapatite (HA-HSP90) and SDS-PAGE/electroelution (eluted-HSP90) to explore the molecular mechanism of HSP90 phosphorylation affecting its metabolism. The purified HSP90 was used as an antigen to raise polyclonal antibodies in rabbits. Immunoblot analysis revealed that most purified HSP90 was HSP90alpha. Compared with the commercial anti-HSP90 antibody, the polyclonal antibody raised in this study could specifically detect the testis HSP90 and immunoprecipitate HSP90 from tissue homogenates or cell extracts. Incubation of the purified HSP90 or HSP90 immunoprecipitated from extracts of human A431 cells, Balb/c 3T3 fibroblasts, and porcine testis with [gamma-32P]ATP/Mg2+ resulted in phosphorylation of HSP90. However, the eluted-HSP90 lost its phosphorylation ability when incubated with [gamma-32P]ATP x Mg2+ alone but could be phosphorylated by various protein kinases, including PKA, CKII, kinase FA/GSK-3 alpha, and AK. The order of phosphorylation of HSP90 by these kinases is PKA = CKII > AK >> kinase FA/GSK-3 alpha.

Whole-body hyperthermia-induced thermotolerance is associated with the induction of Heat Shock Protein 70 in mice

Molecular mechanisms of whole-body thermotolerance (WBT) in mammals have not been investigated thoroughly. The purpose of this study was to assess the induction of the 70 kDa heat shock protein (HSP70) and antioxidant enzyme activity in animal WBT, which was induced by whole-body hyperthermia (WBH) in mice. As a preconditioning treatment, WBH was applied to mice to induce WBT. Synthesis of inducible HSP70 (HSP70i) and quantification of its increased level in liver were investigated by one- and two-dimensional polyacrylamide gel electrophoresis and immunoblotting. HSP70i synthesis in mice liver was induced by non-lethal WBH (41°C, 30 min). When compared to control animals, the level of liver HSP70i increased substantially (by 3.6-fold; P&lt;0.0001). When exposed to 30 min of hyperthermia preconditioning, and after recovery for 48 h, the survival rate was 88.2 %, which was significantly higher than that of the control group (37.5 %; P&lt;0.01). Moreover, the survival rate of animals subjected to preconditioning for 15 min was 72.2 %, which was also significantly higher than that of the control group (P&lt;0.05). In contrast, the survival rate of animals subjected to preconditioning for 45 min was 63.5 %, which was not different from the control group. Nonetheless, the protection index of the group subjected to 15 min and 30 min of preconditioning was 1.93 and 2.37, respectively. Furthermore, to assess their contributions to WBT, the activities of antioxidant enzymes were also measured. After 48 h of recovery in preconditioned animals, hepatic antioxidant enzyme activities, including superoxide dismutase, catalase and glutathione peroxidase, had not changed significantly. To study the molecular mechanism of WBT, we successfully developed a mouse model and suggest that, rather than the activities of antioxidant enzymes, it is HSP70i that has a role to help animals survive during severe heat stress.

Heat shock proteins in canine transmissible venereal tumor

SDS-PAGE, Western blot analysis and immunohistochemical staining were used to detect heat shock proteins (HSPs) 60, 70 and 90 in canine transmissible venereal tumor (CTVT). Tissues tested for HSPs included: (1) tissues from different growth phases of CTVT tumors artificially induced in dogs; (2) tissues from other canine tumors; (3) normal dog tissues. Our results indicate that HSP 60 was consistently higher in CTVT cells in regressing phase than those in progressing phase. However, no detectable antibody response specific to the tested HSPs was found in the sera from CTVT-laden dogs in different growth phases. Although levels of the HSPs were all detectable in CTVT cells, only 60 and 70 were higher in CTVT cells than in normal tissues. In addition, none of the HSPs were detected in cells from five other canine tumors. These data suggest that canine HSP 60 and 70 are potential markers for CTVT and HSP 60 is appear to be involved in CTVT regression.PCR was used to confirm the existence of CTVT cells using primers designed to cover the sequence between the 5' end of c-myc near the first exon and the 3' end outside the LINE gene. Only CTVT samples were positive for this sequence; samples from other tumors and normal tissues were negative. The sequenced PCR products indicated that CTVT from Taiwan and other countries exhibited over 98% sequence homology. This reconfirms that, worldwide, all CTVT cells are very similar.

Characterization of the cDNA encoding the 90 kDa heat-shock protein in the Lepidoptera Bombyx mori and Spodoptera frugiperda

This report presents the first hsp90 complete cDNA sequences from two Lepidoptera. The Bombyx mori full sequence was reconstituted from 15 partial cDNA clones belonging to expressed sequence tag libraries obtained from different tissues or cultured cells, thus showing the ubiquitous expression of the hsp90 gene. The Spodoptera frugiperda cDNA was isolated as a full-length clone from a cDNA library established from the Sf9 cell line. Both cDNAs are highly homologous and display the classical amino acid (aa) stretches representing the HSP90 signature. They potentially encode a 716 aa (B. mori) and a 717 aa (S. frugiperda) protein, with a calculated molecular mass of 83 kDa similar to the Drosophila homologous protein. We show that, unlike the vertebrates, hsp90 is a unique gene in both S. frupiperda and B. mori genomes. Sequencing of the corresponding genomic region shows that, contrary to the dipteran homologous gene, the lepidopteran hsp90 gene does not display any intron. Phylogenetic analysis based on the two lepidopteran and 23 other HSP90 aa sequences displays a high consistency with known phylogeny at both high and low taxonomic levels. Transcriptional analysis performed in S. frugiperda shows that the induction of the hsp90 gene only occurs 14 degrees C above physiological growth conditions (42 degrees C).

Substantial decrease of heat-shock protein 90 precedes the decline of sperm motility during cooling of boar spermatozoa

The decline in boar semen quality after cryopreservation may be attributed to changes in intracellular proteins. Thus, the aim of the present study was to evaluate the change of protein profiles in boar spermatozoa during the process of cooling and after cryopreservation. A total of 9 sexually mature boars (mean age = 25.5+/-12.3 mo) was used. Samples for protein analysis were collected before chilling, after cooling to 15 degrees C, after cooling to 5 degrees C, following thawing after freezing to -100 degrees C, and following thawing after 1 wk of cryopreservation at -196 degrees C. Semen characteristics evaluated included progressive motility and the percentage of morphologically normal spermatozoa. Total proteins from 5x10(6) spermatozoa were separated and analyzed by SDS-PAGE. The results revealed that there was a substantial decrease of a 90 kDa protein in the frozen-thawed spermatozoa. Western blot analysis demonstrated that this protein was 90 kDa heat-shock protein (HSP90). Time course study showed that the decrease of HSP90 in spermatozoa initially occurred in the first hour during cooling to 5 degrees C. When compared with the fresh spermatozoa before chilling, there was a 64% decrease of HSP90 in spermatozoa after cooling to 5 degrees C. However, the motility and percentage of normal spermatozoa did not significantly decrease during this period of treatment. Both declined substantially as the semen was thawed after freezing from -100 degrees C. The results indicated that the decrease of HSP90 precedes the decline of semen characteristics. The length of time between a decrease of HSP90 and the decline in sperm motility was estimated to be 2 to 3 h. Taken together, the above results suggested that a substantial decrease of HSP90 might be associated with a decline in sperm motility during cooling of boar spermatozoa.