Presence Of Hsp70 Research Articles

A longitudinal assessment of heat exposure and biomarkers of kidney function on heat shock protein 70 and antibodies among agricultural workers

BackgroundExposure to extreme heat impacts millions of people worldwide and outdoor workers are among the populations most affected by hot temperatures. Heat stress induces several biological responses in humans, including the production of heat shock proteins (HSP) and antibodies against HSP (anti-HSP) which may play a central role in the body’s cellular response to a hot environment.ObjectiveThis longitudinal study investigated the impact of elevated temperatures and humidity on the presence of HSP70 and anti-HSP70 and examined relationships with markers of kidney function in an at-risk workforce under conditions of extreme heat and exertion in Guatemala.MethodsWe collected ambient temperature and relative humidity data as well as biomarkers and clinical data from 40 sugarcane workers at the start and the end of a 6-month harvest. We used generalized mixed-effects models to estimate temperature effects on HSP70 and anti-HSP70 levels. In addition, we examined trends between HSP70 and anti-HSP70 levels and markers of kidney function across the harvest.ResultsAt the end of the harvest, temperatures were higher, and workers had, on average, higher levels of HSP70 and anti-HSP70 compared to the beginning of the season. We observed significant increasing trends with temperature indices, heat index, and HSP70 levels. Maximum temperature was associated with HSP70 increments after controlling for age, systolic and diastolic blood pressure (β: 0.21, 95% Confidence Interval: 0.09, 0.33). Kidney function decline across the harvest was associated with both higher levels of anti-HSP70 levels at the end of the harvest as well as greater increases in anti-HSP70 levels across the harvest.ConclusionsThese results suggest that workplace heat exposure may increase the production of HSP70 and anti-HSP70 levels and that there may be a relationship between increasing anti-HSP70 antibodies and the development of renal injury. HSP70 holds promise as a biomarker of heat stress in exposed populations.

Physiological and molecular response of cotton (Gossypium hirsutum L.) to heat stress at the seedling stage

The ideal temperature range for the optimal growth and development of cotton is 25 °C–32 °C and high temperature adversely affects the metabolic activities of plant cells. This study was aimed to screen heat-tolerant cotton genotypes based on physiological and molecular parameters. Experiments were carried out during 2019–2020 at the MNS-University of Agriculture, Multan, Pakistan. The research comprised two parts. In the first experiment, 30 cotton genotypes were sown in a completely randomized design with three replications under laboratory conditions for the determination of cell membrane thermostability. Principal component analysis was performed, and four genotypes, i.e., two heat-tolerant (‘CRIS-5A’ and ‘VH-338’) and two heat-sensitive (‘FH-242’ and ‘VH-281’) genotypes, were selected. In the second experiment, the screened cotton genotypes were sown in pots in a factorial complete randomized design with three replications and two treatments (normal and heat treatment). Heat stress was applied at the seedling stage, and eight leaf samples (one from each experimental unit) were collected. Two genes were used for molecular analysis and were amplified in all eight cDNA samples. Molecular analysis indicated the presence of HSP70 and HSP26 genes in the cotton genotypes, and the expression of these genes was measured by using ImageJ software. The gene expression level of HSP70 was very high (16.41%) in ‘VH-281’, which is a heat-sensitive genotype under heat stress. The sensitive genotype ‘FH-242’ exhibited the highest gene expression level of HSP26 (20.32%) under normal conditions. A similar sequence of HSP70 gene of Agave sisalana was amplified for the first time in cotton. It is a good indicator for screening heat tolerant cotton genotypes at the molecular level.

The interaction of heat shock proteins with cellular membranes: a historical perspective.

The interaction of heat shock proteins (HSP) with cellular membranes has been an enigmatic process, initially observed by morphological studies, inferred during the purification of HSP70s, and confirmed after the detection of these proteins on the surface of cancer cells and their insertion into artificial lipid bilayers. Today, the association of several HSP with lipid membranes is well established. However, the mechanisms for membrane insertion have been elusive. There is conclusive evidence indicating that HSP70s have a great selectivity for negatively charged phospholipids, whereas other HSP have a broader spectrum of lipid specificity. HSP70 also oligomerizes upon membrane insertion, forming ion conductance channels. The functional role of HSP70 lipid interactions appears related to membrane stabilization that may play a role during cell membrane biogenesis. They could also play a role as membrane chaperones as well as during endocytosis, microautophagy, and signal transduction. Moreover, HSP membrane association is a key component in the extracellular export of these proteins. The presence of HSP70 on the surface of cancer cells and its interaction with lysosome membranes have been envisioned as potential therapeutic targets. Thus, the biology and function of HSP membrane association are reaching a new level of excitement. This review is an attempt to preserve the recollection of the pioneering contributions of many investigators that have participated in this endeavor.

Hsp70 affects memory formation and behaviorally relevant gene expression in Drosophila melanogaster.

Heat shock proteins, in particular Hsp70, play a central role in proteostasis in eukaryotic cells. Due to its chaperone properties, Hsp70 is involved in various processes after stress and under normal physiological conditions. In contrast to mammals and many Diptera species, inducible members of the Hsp70 family in Drosophila are constitutively synthesized at a low level and undergo dramatic induction after temperature elevation or other forms of stress. In the courtship suppression paradigm used in this study, Drosophila males that have been repeatedly rejected by mated females during courtship are less likely than naive males to court other females. Although numerous genes with known function were identified to play important roles in long-term memory, there is, to the best of our knowledge, no direct evidence implicating Hsp70 in this process. To elucidate a possible role of Hsp70 in memory formation, we used D. melanogaster strains containing different hsp70 copy numbers, including strains carrying a deletion of all six hsp70 genes. Our investigations exploring the memory of courtship rejection paradigm demonstrated that a low constitutive level of Hsp70 is apparently required for learning and the formation of short and long-term memories in males. The performed transcriptomic studies demonstrate that males with different hsp70 copy numbers differ significantly in the expression of a few definite groups of genes involved in mating, reproduction, and immunity in response to rejection. Specifically, our analysis reveals several major pathways that depend on the presence of hsp70 in the genome and participate in memory formation and consolidation, including the cAMP signaling cascade.

A Novel Approach to Anticancer Therapy: Molecular Modules Based on the Barnase:Barstar Pair for Targeted Delivery of HSP70 to Tumor Cells

One important distinction between many tumor cell types and normal cells consists in the translocation of a number of intracellular proteins, in particular the 70 kDa heat shock protein (HSP70), to the surface of the plasma membrane. It has been demonstrated that such surface localization of HSP70 on tumor cells is recognized by cytotoxic effectors of the immune system, which increases their cytolytic activity. The mechanisms behind this interaction are not fully clear; however, the phenomenon of surface localization of HSP70 on cancer cells can be used to develop new approaches to antitumor immunotherapy. At the same time, it is known that the presence of HSP70 on a cell's surface is not a universal feature of cancer cells. Many types of tumor tissues do not express membrane-associated HSP70, which limits the clinical potential of these approaches. In this context, targeted delivery of exogenous HSP70 to the surface of cancer cells with the aim of attracting and activating the cytotoxic effectors of the immune system can be considered a promising means of antitumor immunotherapy. Molecular constructs containing recombinant mini-antibodies specific to tumor-associated antigens (in particular, antibodies specific to HER2/neu-antigen and other markers highly expressed on the surface of a wide range of cancer cells) can be used to target the delivery of HSP70 to tumor tissues. In order to assess the feasibility and effectiveness of this approach, recombinant constructs containing a mini-antibody specific to the HER2/ neu-antigen in the first module and HSP70 molecule or a fragment of this protein in the second module were developed in this study. Strong selective interaction between the modules was ensured by a cohesive unit formed by the barnase:barstar pair, a heterodimer characterized by an unusually high constant of association. During testing of the developed constructs in in vitro models the constructs exhibited targeted binding to tumor cells expressing the HER2/neu antigen and the agents had a significant stimulating effect on the cytotoxic activity of NK cells against the respective cancer cells.

Memory Loss and the Onset of Alzheimer's Disease Could Be Under the Control of Extracellular Heat Shock Proteins.

Alzheimer's disease (AD) is a major contemporary and escalating malady in which amyloid-β (Aβ) peptides are the most likely causative agent. Aβ peptides spontaneously tend to aggregate in extracellular fluids following a progression from a monomeric state, through intermediate forms, ending in amyloid fibers and plaques. It is generally accepted now that the neurotoxic agents leading to cellular death, memory loss, and other AD characteristics are the Aβ intermediate aggregated states. However, Aβ peptides are continuously produced, released into the extracellular space, and rapidly cleared from healthy brains. Coincidentally, members of the heat shock proteins (hsp) family are present in the extracellular medium of healthy cells and body fluids, opening the possibility that hsps and Aβ could meet and interact in the extracellular milieu of the brain. In this perspective and reflection article, we place our investigation showing that the presence of Hsp70s mitigate the formation of low molecular weight Aβ peptide oligomers resulting in a reduction of cellular toxicity, in context of the current understanding of the disease. We propose that it may be an inverse relationship between the presence of Hsp70, the stage of Aβ oligomers, neurotoxicity, and the incidence of AD, particularly since the expression and circulating levels of hsp decrease with aging. Combining these observations, we propose that changes in the dynamics of Hsp70s and Aβ concentrations in the circulating brain fluids during aging defines the control of the formation of Aβ toxic aggregates, thus determining the conditions for neuron degeneration and the incidence of AD.

Heat shock protein 70 potentiates interferon alpha production by plasmacytoid dendritic cells: relevance for cutaneous lupus and vitiligo pathogenesis

Plasmacytoid dendritic cells (pDCs) are a subset of dendritic cells specialized in the production of type I interferon (IFN-α/β) and involved in various cutaneous inflammatory and autoimmune disorders, such as cutaneous lupus erythematosus (CLE) and vitiligo. Heat shock proteins (HSPs) are molecular chaperones essential for maintaining cellular functions, but they can act as a danger signal during inflammation. To decipher the role of HSP70 in the production of IFN-α by pDCs in CLE and vitiligo. Expression of HSP70 and CD123+ pDCs was analysed by immunohistochemistry or immunofluorescence in CLE and vitiligo skin samples. Flow cytometry was performed to analyse expression of HSP70 receptors, activation markers on pDCs and DNA uptake by pDCs in the presence of HSP70. The impact of HSP70 on DNA-induced IFN-α secretion by pDCs was evaluated by enzyme-linked immunosorbent assay (ELISA). The effect of IFN-α on chemokine (C-X-C motif) ligand 9 (CXCL9)/10 gene and protein expression by keratinocytes was determined by real-time polymerase chain reaction and ELISA. Infiltration of pDCs in CLE and progressive vitiligo was primarily located in the epidermis, close to keratinocytes expressing HSP70. In vitro experiments revealed that the pDCs expressing HSP70 receptor Lox-1 (lectin-like oxidized low-density lipoprotein-receptor-1) were able to aggregate HSP70. Exogenous HSP70 induced activation of pDCs and increased the uptake of exogenous DNA. Furthermore, HSP70 potentiated DNA-induced IFN-α production by pDCs. Finally, IFN-α induced expression of CXCL9 and CXCL10 by keratinocytes. These data demonstrate that interaction between HSP70 and pDCs in CLE and vitiligo is a prerequisite for the enhancement of IFN-α production, and could be an interesting target.

Development of a microarray-based assay for efficient testing of new HSP70/DnaK inhibitors

A facile method for testing ATP binding in a highly miniaturized microarray environment using human HSP70 and DnaK from Mycobacterium tuberculosis as biological targets is reported. Supported by molecular modelling studies we demonstrate that the position of the fluorescence label on ATP has a strong influence on the binding to human HSP70. Importantly, the label has to be positioned on the adenine ring and not to the terminal phosphate group. Unlabelled ATP displaced bound Cy5-ATP from HSP70 in the micromolar range. The affinity of a well-known HSP70 inhibitor VER155008 for the ATP binding site in HSP70 was determined, with a EC50 in the micromolar range, whereas reblastin, a HSP90-inhibitor, did not compete for ATP in the presence of HSP70. The applicability of the method was demonstrated by screening a small compound library of natural products. This unraveled that terphenyls rickenyl A and D, recently isolated from cultures of the fungus Hypoxylon rickii, are inhibitors of HSP70. They compete with ATP for the chaperone in the range of 29 µM (Rickenyl D) and 49 µM (Rickenyl A). Furthermore, the microarray-based test system enabled protein–protein interaction analysis using full-length HSP70 and HSP90 proteins. The labelled full-length human HSP90 binds with a half-maximal affinity of 5.5 µg/ml (∼40 µM) to HSP70. The data also demonstrate that the microarray test has potency for many applications from inhibitor screening to target-oriented interaction studies.

The Anti-Inflammatory Effects of the Small Molecule Pifithrin-µ on BV2 Microglia

Neonatal encephalopathy (NE) is a leading cause of childhood death and disability in term infants. Treatment options for perinatal brain injury are limited and developing therapies that target multiple pathways within the pathophysiology of NE are of great interest. Pifithrin-µ (PFT-µ) is a drug with striking neuroprotective abilities in a preclinical model of hypoxia-ischemia (HI)-induced NE wherein cell death is a substantial cause of injury. Work from neurons and tumor cells reports that PFT-µ is able to inhibit p53 binding to the mitochondria, heat shock protein (HSP)-70 substrate binding and activation of the NF-kB pathway. The purpose of this study is to understand whether the neuroprotective effects of PFT-µ also include direct effects on microglia. We utilized the microglial cell line, BV2, and we studied the dose-dependent effect of PFT-µ on M1-like and M2-like phenotype using qRT-PCR and Western blotting, including the requirement for the presence of p53 or HSP-70 in these effects. We also assessed phagocytosis and the effects of PFT-µ on genes within metabolic pathways related to phenotype. We noted that PFT-µ robustly reduced the M1-like (lipopolysaccharide, LPS-induced) BV2 response, spared the LPS-induced phagocytic ability of BV2 and had no effect on the genes related to metabolism and that effects on phenotype were partially dependent on the presence of HSP-70 but not p53. This study demonstrates that the neuroprotective effects of PFT-µ in HI-induced NE may include an anti-inflammatory effect on microglia and adds to the evidence that this drug might be of clinical interest for the treatment of NE.

Immunoregulatory properties of Hsp70

Heat shock proteins 70 (Hsp70) play an important role in maintaining cellular homeostasis. As molecular chaperones, Hsp70 are responsible for proper folding of newly synthesized polypeptides and refolding of misfolded and aggregated proteins. Hsp70 are involved in cellular transport and participate in signal transduction processes. The presence of Hsp70 in the extracellular space is associated with development of various pathological conditions, including autoimmune and cancer diseases. Recent data suggest anti-inflammatory property of Hsp70 confirmed in both in vitro and animal models. This paper summarizes recent data regarding immunoregulatory properties of Hsp70, and presents promising results of the studies concerning the application of heat shock proteins in treatment of chronic inflammatory diseases.

Hsp70 regulates the doxorubicin-mediated heart failure in Hsp70-transgenic mice.

The aim of this study was to investigate the potential protective effect of the Hsp70 protein in the cardiac dysfunction induced by doxorubicin (DOX) and the mechanisms of its action. For this purpose, we used both wild-type mice (F1/F1) and Hsp70-transgenic mice (Tg/Tg) overexpressing human HSP70. Both types were subjected to chronic DOX administration (3 mg/kg intraperitoneally every week for 10 weeks, with an interval from weeks 4 to 6). Primary cell cultures isolated from embryos of these mice were also studied. During DOX administration, the mortality rate as well as weight reduction were lower in Tg/Tg compared to F1/F1 mice (P < 0.05). In vivo cardiac function assessment by transthoracic echocardiography showed that the reduction in left ventricular systolic function observed after DOX administration was lower in Tg/Tg mice (P < 0.05). The study in primary embryonic cell lines showed that the apoptosis after incubation with DOX was reduced in cells overexpressing Hsp70 (Tg/Tg), while the apoptotic pathway that was activated by DOX administration involved activated protein factors such as p53, Bax, caspase-9, caspase-3, and PARP-1. In myocardial protein extracts from identical mice with DOX-induced heart failure, the particular activated apoptotic pathway was confirmed, while the presence of Hsp70 appeared to inhibit the apoptotic pathway upstream of the p53 activation. Our results, in this DOX-induced heart failure model, indicate that Hsp70 overexpression in Tg/Tg transgenic mice provides protection from myocardial damage via an Hsp70-block in p53 activation, thus reducing the subsequent apoptotic mechanism.

Test-System For Observing Heat Shock Protein 70kDa (Hsp70) Effect On Reactive Oxygen Species Production By Immune Cells.

Event Abstract Back to Event Test-System For Observing Heat Shock Protein 70kDa (Hsp70) Effect On Reactive Oxygen Species Production By Immune Cells. NATALIA TROYANOVA1*, Ruslan Mirzoev1 and Aleksander Sapozhnikov1 1 Shemyakin–Ovchinnikov Institute of bioorganic chemistry RAS, Russia One of the most important aspects of the ROS biological activity is associated with the damaging effect on pathogens. But elevated ROS level can also lead to tissue damage. However, not all the mechanisms of ROS production regulation in cells are well investigated. We speculate that heat shock protein 70kDa (Hsp70) extracellular form may be one of the endogenous suppressors of the excessive ROS production by phagocytes. The aim was to determine antioxidant potential of Hsp70. Initially we have shown that 10 min heat stress treatment of the murine bone marrow cells with 60 min recovery at 37oC, prior to phorbol-12-myristate-13-acetate (PMA) activation, significantly reduced the intensity of the following ROS production compared with the control. Already after 5 min incubation in presence of Hsp70 we observed significant reduction of PMA-induced oxidative burst amplitude. The minimal concentration of Hsp70 required for the decrease of ROS production was strongly dependent from the incubation time and prolonged incubation decreased the effective Hsp70 concentration to 0.1 µg/ml. Strong dose-dependent effect of HSP70 was observed in the case of prolonged incubation. Besides effects on oxidative burst, Hsp70 reduces the level of spontaneous ROS production by the cells, which could be important in the process of aging regulation. In addition to the murine bone marrow model, the effect of HSP70 on oxidative burst was also demonstrated on human monocytes cell line THP-1. So, the antioxidant dose- and time-dependent effect of exogenously supplied Hsp70 on spontaneous and induced ROS production was shown using different cell models. Keywords: ROS, oxidative burst, Hsp70, Antioxidants, innate immunity Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Innate immunity Citation: TROYANOVA N, Mirzoev R and Sapozhnikov A (2013). Test-System For Observing Heat Shock Protein 70kDa (Hsp70) Effect On Reactive Oxygen Species Production By Immune Cells.. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00119 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 10 Mar 2013; Published Online: 22 Aug 2013. * Correspondence: Miss. NATALIA TROYANOVA, Shemyakin–Ovchinnikov Institute of bioorganic chemistry RAS, Moscow, Russia, natywa@list.ru Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers NATALIA TROYANOVA Ruslan Mirzoev Aleksander Sapozhnikov Google NATALIA TROYANOVA Ruslan Mirzoev Aleksander Sapozhnikov Google Scholar NATALIA TROYANOVA Ruslan Mirzoev Aleksander Sapozhnikov PubMed NATALIA TROYANOVA Ruslan Mirzoev Aleksander Sapozhnikov Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Insertion of Hsp70 into Membranes is Mediated by Negative-Charged Phospholipids and Modulated by the Fluidity of the Bilayer

The universal response to stress is mediated by the expression of heat shock proteins (hsp), which are involved in repair and recovery from the insult. In addition, their presence provides protection from subsequent insults, which has been coined stress tolerance. The cytoprotective role of hsp has been associated with their chaperone function within the cytosol. However, hsp were recently found outside cells where they acted as signaling molecules directed at activating the immune system to avoid the propagation of the insult. Hsp70, the major inducible form of the hsp family, does not contain any consensus secretory signal that predicts its secretion via the ER-Golgi pathway. Therefore, it is likely that the export of Hsp70 to the extracellular environment is mediated by the propose that Hsp70 is exported by a novel mechanism initiated by the translocation of the protein into the plasma membrane and is released associated with vesicles called export or extracellular vesicles (ECV). To test this hypothesis, we developed a liposome insertion assay using pure recombinant Hsp70. We found that Hsp70 insertion into lipid membranes was spontaneous and specific for negatively charged lipids, such as phosphatidylserine and phosphatidylglycerol. In contrast, positive or neutral lipids did not support membrane insertion. We also found that less fluid lipid environments highly favored membrane insertion, which resembles in vivo observations indicating the presence of Hsp70 in lipid rafts of cells. In summary, our observations support the hypothesis that membrane insertion is the first stage of secretion of Hsp70 into the extracellular environment in the form of vesicles. We speculate that hsp70-ECV may result in a robust activation of the immune system that is part of the systemic response to stress.Supported by NIH R01 GM098455.

Regulation of G protein signaling by the 70 kDa heat shock protein

G protein-coupled receptors (GPCRs) transduce extracellular signals to the interior of the cell by activating membrane-bound guanine nucleotide-binding regulatory proteins (G proteins). An increasing number of proteins have been reported to bind to and regulate GPCRs. We report a novel regulation of the alpha2A adrenergic receptor (α2A-R) by the ubiquitous stress-inducible 70kDa heat shock protein, hsp70. Hsp70, but not hsp90, attenuated G protein-dependent high affinity agonist binding to the α2A-R in Sf9 membranes. Antagonist binding was unchanged, suggesting that hsp70 uncouples G proteins from the receptor. As hsp70 did not bind G proteins but complexed with the α2A-R in intact cells, a direct interaction with the receptor seems likely. In the presence of hsp70, α2A-R-catalyzed [35S]GTPγS binding was reduced by approximately 70%. In contrast, approximately 50-fold higher concentrations of hsp70 were required to reduce agonist binding to the stress-inducible 5-hydroxytryptamine1A receptor (5-HT1A-R). In heat-stressed CHO cells, the α2A-R was significantly uncoupled from G proteins, coincident with an increased localization of hsp70 at the membrane. The contrasting effect of hsp70 on the α2A-R compared to the 5-HT1A-R suggests that during stress, upregulation of hsp70 may attenuate signaling from specific GPCRs as part of the stress response to foster survival.

Ultrastructure of Rabbit Embryos Exposed to Hyperthermia and Anti-Hsp 70

The aim of the study was to determine the effect of short-term hyperthermia and Hsp70 blockage on ultrastructural changes in cell organelles and nucleoli of rabbit preimplantation embryos. The embryos were cultured either at 37.5°C (control, C) or 41.5°C (hyperthermia, HT) during 6 h. The antibody against Hsp70 was added into the culture medium (4 μg/ml) of morula stage embryos from C and HT groups. After termination of the culture, the embryos were processed for transmission electron microscopy. The embryos exposed to hyperthermia showed increased volume of lipid droplets, considerable occurrence of cellular debris in the perivitelline space and slight changes in the occurrence of microvilli on the surface of trophoblastic cells. In the embryos exposed to anti-Hsp 70 at 37.5°C, there were considerable changes in mitochondria morphology, decreased volume of dense bodies in the cytoplasm and considerable changes in the occurrence of microvilli on the surface of trophoblastic cells. In the group of embryos exposed simultaneously to hyperthermia and anti-Hsp 70, mitochondria were also expanded and swollen; the volume of flocculent vesicles and lipid droplets was increased and the volume of dense bodies in the cytoplasm was diminished. General organization of the cytoplasm in groups with anti-Hsp70 was characterized by cell organelle segregation. Averaged size of the nucleolar area was significantly increased in the embryos exposed to hyperthermia, whereas in the group exposed to the anti-Hsp70 without hyperthermia it was significantly diminished. Hyperthermia also caused disintegration of compact status of the nucleoli. In presence of anti-Hsp 70, the structural changes, described within the nucleoli during hyperthermia, were not observed. In conclusion, these results document ultrastructural changes in cell organelles of rabbit preimplantation embryo caused by hyperthermia, and also changes in the nucleolar structures, at which presence of Hsp-70 inhibit these changes.

Abstract 1561: Leukemia cell-derived exosomes targeted dendritic cells can induce more strong anti-leukemia response than exosomes alone

Abstract Exosomes are the newest family number of ‘bioactive vesicles’ that play important roles in antigen presentation. Recent clinical trials about exosomes have shown minor clinical benefit. However, exosomes derived from leukemia cell lines were less studied, In this study, we investigated the biological properties and anti-leukemia immunity of leukemia cell-derived exosomes (LEX). The results showed that like other tumor cells, similarly, leukemia cells can release exosomes too. Transmission electron microscopy showed that exosomes derived from NB4 cell, a promyloblastic leukemia cell line and K562 cell, a chronic myeloid leukemia cell line were membrane vesicles with diameter about 50-100μm, and loading their specific moleculars such as RAR-α and ABL and adherent moleculars such as ICAM-1. Similarly, our data also demonstrated the presence of Hsp70 in these two leukemia cell-derived exosomes. The data from two-dimensional electrophoresis of K562 cell-derived exosomes showed that most of molecules expressing on leukemia cells were detected on their exosomes, indicating that LEX load most of proteins expressed on their original leukemia cells. Out data also demonstrated that LEX can induce anti-leukemia CTL response and LEX-targeted DC can induce more efficient anti-leukemia immunity compared with LEX alone. In conclusion, exosome-based therapies could be considered as a promising strategy to prolong disease-free survival in patients with leukemia after consolidation or hematopoietic stem cell transplantation. Note: This research work was supported by research grants from Shanghai Pujiang Project of Science and Technology Commission of Shanghai Municipality. Keywords: Exosome, leukemia cell, anti-leukemia immunity Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1561. doi:1538-7445.AM2012-1561

Plasmodium falciparum-Infected Erythrocytes Induce Granzyme B by NK Cells through Expression of Host-Hsp70

In the early immune response to Plasmodium falciparum-infected erythrocytes (iRBC), Natural Killer (NK) cells are activated, which suggests an important role in innate anti-parasitic immunity. However, it is not well understood whether NK cells directly recognize iRBC or whether stimulation of NK cells depends mainly on activating signals from accessory cells through cell-to-cell contact or soluble factors. In the present study, we investigated the influence of membrane-bound host Heat shock protein (Hsp) 70 in triggering cytotoxicity of NK cells from malaria-naïve donors or the cell line NK92 against iRBC. Hsp70 and HLA-E membrane expression on iRBC and potential activatory NK cell receptors (NKG2C, CD94) were assessed by flow cytometry and immunoblot. Upon contact with iRBC, Granzyme B (GzmB) production and release was initiated by unstimulated and Hsp70-peptide (TKD) pre-stimulated NK cells, as determined by Western blot, RT-PCR and ELISPOT analysis. Eryptosis of iRBC was determined by Annexin V-staining. Our results suggest that presence of Hsp70 and absence of HLA-E on the membrane of iRBC prompt the infected host cells to become targets for NK cell-mediated cytotoxicity, as evidenced by impaired parasite development. Contact of iRBC with NK cells induced release of GzmB. We propose that following GzmB uptake, iRBC undergo eryptosis via a perforin-independent, GzmB-mediated mechanism. Since NK activity toward iRBC could be specifically enhanced by TKD peptide and abrogated to baseline levels by blocking Hsp70 exposure, we propose TKD as an innovative immunostimulatory agent to be tested as an adjunct to anti-parasitic treatments in vivo.

In vivo analysis of laser preconditioning in incisional wound healing of wild‐type and HSP70 knockout mice with Raman spectroscopy

Laser preconditioning augments incisional wound healing by reducing scar tissue and increasing maximum tensile load of the healed wound [Wilmink et al. (2009) J Invest Dermatol 129(1): 205-216]. Recent studies have optimized treatments or confirmed results using HSP70 as a biomarker. Under the hypothesis that HSP70 plays a role in reported results and to better understand the downstream effects of laser preconditioning, this study utilized a probe-based Raman spectroscopy (RS) system to achieve an in vivo, spatio-temporal biochemical profile of murine skin incisional wounds as a function of laser preconditioning and the presence of HSP70. A total of 19 wild-type (WT) and HSP70 knockout (HSP70-/-) C57BL/6 mice underwent normal and laser preconditioned incisional wounds. Laser thermal preconditioning was conducted via previously established protocol (λ = 1.85 µm, H(0 ) = 7.64 mJ/cm(2) per pulse, spot diameter = 5 mm, Rep. rate = 50 Hz, τ(p) = 2 milliseconds, exposure time = 10 minutes) with an Aculight Renoir diode laser, with tissue temperature confirmed by real-time infrared camera measurements. Wound-healing progression was quantified by daily collection of a spatial distribution of Raman spectra. The results of RS findings were then qualified using standard histology and polarization microscopy. Raman spectra yielded significant differences (t-test; α = 0.05) in several known biochemical peaks between WT and HSP70 (-/-) mice on wounds and in adjacent tissue early in the wound-healing process. Analysis of peak ratios implied (i) an increase in protein configuration in and surrounding the wound in WT mice, and (ii) an increased cellular trend in WT mice that was prolonged due to laser treatment. Polarization microscopy confirmed that laser treated WT mice showed increased heterogeneity in collagen orientation. The data herein supports the theory that HSP70 is involved in normal skin protein configuration and the cellularity of early wound healing. Laser preconditioning extends cellular trends in the presence of HSP70. Despite study limitations, RS provided a non-invasive method for quantifying temporal trends in altered wound healing, narrowing candidates and design for future studies with clinically applicable instrumentation.

Hsp70 Alters Tau Function and Aggregation in an Isoform Specific Manner

Tauopathies are characterized by abnormal aggregation of the microtubule associated protein tau. This aggregation is thought to occur when tau undergoes shifts from its native conformation to one that exposes hydrophobic areas on separate monomers, allowing contact and subsequent association into oligomers and filaments. Molecular chaperones normally function by binding to exposed hydrophobic stretches on proteins and assisting in their refolding. Chaperones of the heat shock protein 70 (Hsp70) family have been implicated in the prevention of abnormal tau aggregation in adult neurons. Tau exists as six alternatively spliced isoforms, and all six isoforms appear capable of forming the pathological aggregates seen in Alzheimer's disease. Because tau isoforms differ in primary sequence, we sought to determine whether Hsp70 would differentially affect the aggregation and microtubule assembly characteristics of the various tau isoforms. We found that Hsp70 inhibits tau aggregation directly and not through inducer-mediated effects. We also determined that Hsp70 inhibits the aggregation of each individual tau isoform and was more effective at inhibiting the three repeat isoforms. Finally, all tau isoforms robustly induced microtubule formation while in the presence of Hsp70. The results presented herein indicate that Hsp70 affects tau isoform dysfunction while having very little impact on the normal function of tau to mediate microtubule assembly. This indicates that targeting Hsp70 to tau may provide a therapeutic approach for the treatment of tauopathies that avoids disruption of normal tau function.

αα-Synuclein Interactions with Hsp70

α-Synuclein (αS) is an intrinsically disordered neuronal protein that forms amyloid fibers in Parkinson's disease (PD). Hsp70 is an ATP-dependent molecular chaperone that may inhibit and reverse protein misfolding. It has been shown that Hsp70 can inhibit αS aggregation and mediate αS toxicity in some model systems, as well as promote degradation of soluble αS. There is, however, conflicting evidence as to whether Hsp70 interacts directly with monomeric or oligomeric αS. Moreover, there is very little information on how Hsp70 may modulate interactions between αS and lipid membranes, an area of interest because it is thought that oligomeric αS may cause neuronal cell death through direct interactions with cellular membranes. In this work, binding of wildtype and pathological αS monomers and oligomers to Hsp70 was measured by fluorescence correlation spectroscopy to detect the direct interaction between αS and Hsp70. In addition, the effect of Hsp70 on αS membrane binding was observed to probe the mechanism of reduced αS toxicity in the presence of Hsp70.