Developmental study of thermotolerance and the heat shock response inLucilia cuprina (Weidemann)

The ability to withstand thermal stress in a laboratory population of the blowflyLucilia cuprina (measured as per cent adult survival following varying periods of exposure to elevated temperature up to a maximum of 48°C) was in the order pupa > larva > adult. Pre-exposure to a mild heat shock (37°C) induced tolerance to temperatures which were otherwise lethal. An analysis of heat shock-induced protein synthesis during development at similar elevated temperatures presented patterns corresponding to the above observations on thermotolerance. The induced level of synthesis of major heat shock proteins (viz., 79, 69, 28, 20 and 19 kDa) were greater in larval tissues than in most of the adult tissues except gonads. The response varied between young (2 days) and old (30 days) adults in a tissue-specific manner. In general, heat shock protein 69 kDa was most abundant in all the tissues studied. Control as well as heat shocked Malpighian tubules of adults uniquely showed two major [³⁵S]methionine labelled bands corresponding to approximately 62 and 64 kDa. Immunoblots showed the 62 kDa protein to cross react with an antibody againstHelioihis HSP60. Although the synthesis of the 62 kDa polypeptide was prominent only in Malpighian tubules of adult blowflies, nearly equal levels of this HSP60 family polypeptide were present in all tissues (control as well heat shocked) except the larval salivary glands.     

Tissue-specific expression of heat shock proteins of the mouse in the absence of stress

The steady-state levels of four members of the heat shock proteins families (HSP84, HSC73, HSP71, and HSP25) were examined by immunoblot analysis of several different tissues of young and adult mice in the absence of stress. These hsps were detected in all tissues but their level was variable. The levels of HSC73 and HSP84 varied only slightly between different tissues in either young or adult mice, with the exception of skin where these hsps were found in reduced amounts. In contrast, the stress-inducible member of the HSP70 family, HSP71, was found to be expressed in all tissues but in amounts which differed by as much as two orders of magnitude between tissues. In general, the levels of both HSP71 and HSP25 were found to be tissue dependent, with higher levels found in tissues such as stomach, intestine, colon and bladder, tissues which are exposed to toxic environmental or metabolic products, and which may concentrate these substances by water resorption and/or be exposed to them for longer periods. The levels of HSP71 and HSP25 were generally positively correlated both in young and adult mice although this correlation was not found in certain tissues such as kidney, testes, and bone. Tissues of young mice contained lower amounts of HSP25 and HSP71 than were found in the same tissues from adults. We conclude that hsps are expressed in all tissues of the mouse in the absence of stress and that some organs, particularly those exposed to potentially toxic metabolites, show a higher level of expression of HSP71 and HSP25. © 1993Wiley-Liss, Inc.     

Induction of Antioxidant and Heat Shock Protein Responses During Torpor in the Gray Mouse Lemur,Microcebus murinus

A natural tolerance of various environmental stresses is typically supported by various cytoprotective mechanisms that protect macromolecules and promote extended viability. Among these are antioxidant defenses that help to limit damage from reactive oxygen species and chaperones that help to minimize protein misfolding or unfolding under stress conditions. To understand the molecular mechanisms that act to protect cells during primate torpor, the present study characterizes antioxidant and heat shock protein(HSP) responses in various organs of control(aroused)and torpid gray mouse lemurs, Microcebus murinus. Protein expression of HSP70 and HSP90 a was elevated to 1.26 and 1.49 fold, respectively, in brown adipose tissue during torpor as compared with control animals, whereas HSP60 in liver of torpid animals was 1.15 fold of that in control(P 0.05). Among antioxidant enzymes, protein levels of thioredoxin 1 were elevated to 2.19 fold in white adipose tissue during torpor, whereas Cu–Zn superoxide dismutase 1 levels rose to 1.1 fold in skeletal muscle(P 0.05). Additionally, total antioxidant capacity was increased to 1.6 fold in liver during torpor(P 0.05), while remaining unchanged in the five other tissues. Overall, our data suggest that antioxidant and HSP responses are modified in a tissue-specific manner during daily torpor in gray mouse lemurs. Furthermore, our data also show that cytoprotective strategies employed during primate torpor are distinct from the strategies in rodent hibernation as reported in previous studies.     

Heat shock protein expression analysis in canine osteosarcoma reveals HSP60 as a potentially relevant therapeutic target

Heat shock proteins (HSP) are highly conserved across eukaryotic and prokaryotic species. These proteins play a role in response to cellular stressors, protecting cells from damage and facilitating recovery. In tumor cells, HSPs can have cytoprotective effects and interfere with apoptotic cascades. This study was performed to assess the prognostic and predictive values of the gene expression of HSP family members in canine osteosarcoma (OS) and their potential for targeted therapy. Gene expressions for HSP were assessed using quantitative PCR (qPCR) on 58 snap-frozen primary canine OS tumors and related to clinic-pathological parameters. A significant increased expression of HSP60 was found in relation to shorter overall survival and an osteoblastic phenotype. Therefore, the function of HSP60 was investigated in more detail. Immunohistochemical analysis revealed heterogeneous staining for HSP60 in tumors. The highest immunoreactivity was found in tumors of short surviving dogs. Next HSP expression was shown in a variety of canine and human OS cell lines by qPCR and Western blot. In two highly metastatic cell lines HSP60 expression was silenced using siRNA resulting in decreased cell proliferation and induction of apoptosis in both cell lines. It is concluded that overexpression of HSP60 is associated with a poor prognosis of OS and should be evaluated as a new target for therapy.     

Characterization of HSP70 expression in drones of Apis cerana (Hymenoptera: Apidae)

Heat shock proteins (HSPs) constitute a superfamily of molecular chaperones that are rapidly biosynthesized in response to various biotic and abiotic factors. In this study, we first cloned the full-length HSP70 gene of the Eastern honeybee Apis cerana. Then, using real-time quantitative PCR, we explored HSP70 expression profiles in drones at different developmental stages, ages, and reproductive statuses (with and without semen). The full-length HSP70 cDNA is 2421 bp, including a 1953-bp open reading frame (ORF) that encodes a polypeptide of 650 amino acids. The HSP70 gene consists of one intron and two exons. The phylogenetic analysis revealed that the HSP70 genes of A. cerana and Apis mellifera are the most closely related. We observed HSP70 expression at all selected developmental stages and detected the highest expression in pupae with an unpigmented body cuticle and brown eyes (Pb) and much lower expression in larvae hatched within 72 h. In adult drones of different ages, the highest expression level of HSP70 was observed in 16-day-old drones; significantly lower accumulation of HSP70 mRNA was detected in 4-day-old drones. There was no significant difference in HSP70 expression between drones with and without semen captured at the entrance, while the HSP70 gene expression level strikingly differed between drones captured at the entrance and the drones collected within the hive. Our study suggests that HSP70 might play a critical role in drone development and during reproductive mating events.     

Insights into function and regulation of small heat shock protein 25 (HSPB1) in a mouse model with targeted gene disruption

The mammalian small heat shock protein (sHSPs) family is comprised of 10 members and includes HSPB1, which is proposed to play an essential role in cellular physiology, acting as a molecular chaperone to regulate diverse cellular processes. Whilst differential roles for sHSPs are suggested for specific tissues, the relative contribution of individual sHSP family members in cellular and organ physiology remains unclear. To address the function of HSPB1 in vivo and determine its tissue-specific expression during development and in the adult, we generated knock-in mice where the coding sequence of hspb1 is replaced by a lacZ reporter gene. Hspb1 expression marks myogenic differentiation with specific expression first confined to developing cardiac muscles and the vascular system, and later in skeletal muscles with specific expression at advanced stages of myoblast differentiation. In the adult, hspb1 expression was observed in other tissues, such as stratified squamous epithelium of skin, oronasal cavity, tongue, esophagus, and uterine cervix but its expression was most prominent in the musculature. Interestingly, in cardiac muscle hsbp1 expression was down-regulated during the neonatal period and maintained to a relatively low steady-level throughout adulthood. Despite this widespread expression, hspb1-/- mice were viable and fertile with no apparent morphological abnormalities in tissues under physiological conditions. However, at the cellular level and under stress conditions (heat challenge), HSPB1 act synergistically with the stress-induced HSPA1 (HSP70) in thermotolerance development, protecting cells from apoptosis. Our data thus indicate a nonessential role for HSPB1 in embryonic development and for maintenance of tissues under physiological conditions, but also shows that it plays an important role by acting synergistically with other HSPs during stress conditions to exert cytoprotection and anti-apoptotic effects.     

Expression of heat shock proteins in adult honey bee (Apis mellifera L.) workers under hot-arid subtropical ecosystems

Heat stress elicits the expression of heat shock proteins (HSPs) in honey bee subspecies. These highly conserved proteins have significant role in protecting cells from thermal-induced stresses. Honey bees in subtropical regions face extremely dry and hot environment. The expression of HSPs in the nurses and foragers of indigenous (Apis mellifera jemenitica) and imported European (Apis mellifera ligustica and Apis mellifera carnica) honey bee subspecies after heat shock treatment were compared using SDS-PAGE. Hsp70 and Hsp82 were equally expressed in the nurses of all tested bee subspecies when exposed to 40 °C and 45 °C for 4 h. The forager bees exhibited differential expression of HSPs after heat stress. No HSPs was expressed in the foragers of A. m. jemenitica, and Hsp70 was expressed only in the foragers of A. m. ligustica and A. m. carnica at 40 °C. A prominent diversity in HSPs expression was also exhibited in the foragers at 45 °C with one HSP (Hsp70) in A. m. jemenitica, two HSPs (Hsp40 and Hsp70) in A. m. carnica, and three HSPs (Hsp40, Hsp60 and Hsp70) in A. m. ligustica. No HSPs was expressed in the control nurse and forager bees at any of the tested temperatures. These findings illustrated the differences in HSP expression among nurse and forager bees. It is obvious that the native foragers are more heat tolerant with least HSPs expression than exotic bee races. Further investigations will help to understand the potential role of HSPs in the adaptability, survival, and performance of bee subspecies in harsh climate of the subtropical regions.     

植物热激蛋白的功能及其基因表达的调控

本文介绍了植物热激蛋白的产生、分布和分类。着重论述了热激反应的特点、植物热激蛋白的功能、热激基因表达与调控的研究进展     

Gambogic acid and gambogenic acid induce a thiol-dependent heat shock response and disrupt the interaction between HSP90 and HSF1 or HSF2

Cancer cells rely on heat shock proteins (HSPs) for growth and survival. Especially HSP90 has multiple client proteins and plays a critical role in malignant transformation, and therefore different types of HSP90 inhibitors are being developed. The bioactive natural compound gambogic acid (GB) is a prenylated xanthone with antitumor activity, and it has been proposed to function as an HSP90 inhibitor. However, there are contradicting reports whether GB induces a heat shock response (HSR), which is cytoprotective for cancer cells and therefore a potentially problematic feature for an anticancer drug. In this study, we show that GB and a structurally related compound, called gambogenic acid (GBA), induce a robust HSR, in a thiol-dependent manner. Using heat shock factor 1 (HSF1) or HSF2 knockout cells, we show that the GB or GBA-induced HSR is HSF1-dependent. Intriguingly, using closed form ATP-bound HSP90 mutants that can be co-precipitated with HSF1, a known facilitator of cancer, we show that also endogenous HSF2 co-precipitates with HSP90. GB and GBA treatment disrupt the interaction between HSP90 and HSF1 and HSP90 and HSF2. Our study implies that these compounds should be used cautiously if developed for cancer therapies, since GB and its derivative GBA are strong inducers of the HSR, in multiple cell types, by involving the dissociation of a HSP90-HSF1/HSF2 complex.     

结直肠癌中HSP60和HSP27表达的免疫组织化学研究

目的1观察热休克蛋白60和热休克蛋白27在结直肠癌中的表达及意义。方法：收集结直肠癌80例,其中淋巴结转移40例（转移组）,无淋巴结转移40例（无转移组）;另外,在结直肠癌80例中,有结直肠腺瘤（腺瘤组）以及距肿块15cm以上的正常肠粘膜（对照组）各40例。应用免疫组织化学SP法检测组织中蛋白的表达。结果：HSP60的表达主要定位在癌细胞胞浆,在对照组、腺瘤组、非转移组、转移组中的表达阳性率分别为25％、30％、57．5％、90％,组间比较发现,对照组与转移组、腺瘤组与转移组、转移组与非转移组（x^2=10．912,P〈0．001）的HSP60阳性表达率存在统计学差异;而对照组与腺瘤和非转移组间以及腺瘤与非转移组间无统计学差异。HSP27的表达主要定位在癌细胞的胞浆,在对照组、腺瘤组、非转移组、转移组的表达阳性率分别为5％,35％,50％,90％,组间比较发现,对照组分别与无淋巴结转移组、淋巴结转移组;腺瘤组分别与转移组;非转移组与转移组间存在统计学差异,腺瘤与非转移组间无统计学差异。HSP60和HSP27表达间无统计学相关。结论：HSP27表达可能与结直肠癌发生和转移相关。而HSP60的表达可能在结直肠癌转移中具有重要意义。     

Tissue-specific localization of heat-stress proteins during embryo development

We report on the stress-independent, tissue-specific expression of the heat-stress protein HSP17 in developing seeds of different plant species and on its intracellular localization. Though HSP17 expression during seed development seems to be a general phenomenon, the isoform patterns, the relative amounts in embryonic tissues and the intracellular localization show species-specific variations. In contrast to the results on the stressinduced protein forming large cytoplasmic aggregates (heat stress granules) the developmentally expressed HSP17 is mainly found in nuclei. But in addition, a considerable part is also detected in protein bodies of mature seeds of Lycopersicon esculentum and Vicia faba, but not of Zea mays. The mechanism of this transition into the vacuolar compartment remains to be investigated.Abbreviations 2D two-dimensional - HSE heat shock elements - HSP heat stress protein     

Characterisation and subcellular localisation of the GroEL-like and DnaK-like proteins isolated from Fusobacterium nucleatum ATCC 10953

Fusobacterium nucleatum is associated with periodontitis in humans, and is a central member of the dental biofilm. Heat shock proteins (HSPs) of many different bacteria have been considered to play important roles during inflammations and infections. We have identified and characterised the HSP60 and HSP70, the Escherichia coli GroEL and DnaK homologues, respectively, in F. nucleatum ATCC 10953. The N-terminal 22 amino acid residues of HSP60 exhibited up to 63.6% identity with members of the HSP60 heat shock protein family of some selected bacterial species, while the N-terminal of 25 residues of HSP70 revealed up to 80% identity with members of the HSP70 family. The subcellular localisation of HSP60 and HSP70 was analysed by immunoblotting of bacterial cell fractions and immunoelectron microscopy of whole cells. HSP60 and HSP70 were localised in the cytosol, associated with membranes and extracellular fractions. These results are consistent with localisation for HSPs found in other micro-organisms, which further lead to the suggestion of a potential role in the pathogenesis of infectious diseases.