Heat shock proteins: to present or not, that is the question

Molecular Cloning of Heat Shock Protein 60 (SpHSP60) from Schizothorax prenanti and the Gene Expressions of Four SpHSPs during Lipopolysaccharide (LPS) Infection

Heat shock proteins (HSPs) play a key role in anti-stress and immune processes and are associated with autoimmune diseases. In order to explore the immunological role of HSPs from Schizothorax prenanti (S. prenanti), SpHSP60 was cloned for the first time in this study, and the gene expressions of SpHSP27, SpHSP60, SpHSP70 and SpHSP90 in the hepatopancreas, head kidney, hindgut and spleen were analyzed by quantitative real-time PCR (qPCR) after treatment with lipopolysaccharide (LPS). The open reading frame of the SpHSP60 gene (GenBank accession number ON245159) is 1728 bp. It encodes a protein of 575 amino acids. Its C-terminus is a highly conserved and repeated glycine sequence, which is an important cofactor in ATP binding. Compared with the control group, most of the SpHSPs were significantly upregulated in the tissues examined at 12 or 24 h after LPS challenge. The most abundant expression of SpHSP70 was found in the head kidney at 24 h after LPS injection, followed by SpHSP27 in the spleen at 24 h; both of these SpHSPs displayed strong expression under the LPS stresses, about 20–70 fold more than that of SpHSP60 and SpHSP90. The temporal expression patterns of the four SpHSP genes were different in the four tissues examined. Taken together, the results suggest that SpHSP27, SpHSP60, SpHSP70 and SpHSP90 participate in innate immunity stimulated by LPS, and the response intensity of the SpHSPs was organ-specific, indicating they could provide early warning information against bacterial infection. The findings in our study will contribute to better understanding the biological processes and important roles of SpHSPs involved in defending against pathogenic bacterial challenge.

Synergistic Effects of Dietary Selenomethionine and Vitamin C on the Immunity, Antioxidant Status, and Intestinal Microbiota in Sea Cucumber (Apostichopus japonicus)

A 30-day feeding trial was carried out to investigate the interactive effects of dietary selenium (selenomethionine) and vitamin C (Vc) in Apostichopus japonicus. Two selenium (0 and 5 mg/kg) and three vitamin C (0, 5000, and 10,000 mg/kg) combined groups of feed were formulated (Designated as LSeLVc, LSeMVc, LSeHVc, HSeLVc, HSeMVc and HSeHVc, respectively) and fed the sea cucumbers. Our results showed no significant effects on the growth-related parameters in sea cucumber (P > 0.05). Furthermore, the reciprocal action between Se and Vc had significant (P < 0.05) effects on Se accumulation in the respiratory tree and intestines. Also, the lysozyme, glutathione peroxidase activity, and the relative expression levels such as LZM, GPX, Hsp70, and Hsp90 in different tissues were significantly increased in the group of sea cucumber fed diet with 5 mg Se in combination with 5000 mg Vc compared with the control group (P < 0.05). However, MDA and H2O2 contents in the body wall were significantly reduced in the HSeHVc group (P < 0.05). In addition, analysis of intestinal flora revealed that Haloferula abundance was highest in the LSeMVc group than other treatment groups, and Vibrio abundance was decreased with combined Se and Vc supplement. Finally, the species diversity of the gut microbial community of sea cucumber in HSeMVc group was lower than those in other treatment groups. The results showed that the interaction of selenium and vitamin C had positive effects on improving the immune status, antioxidant capacity, and digestive ability of A. japonicus.

HSP70-eIF4G Interaction Promotes Protein Synthesis and Cell Proliferation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide and features various tumor escape mechanisms from treatment-induced stress. HSP70 plays a critical role in cell protection under stress. eIF4G physiologically regulates the formation of the protein-ribosomal complex and maintains cellular protein synthesis. However, the precise cooperation of both in HCC remains poorly understood. In this study, we demonstrate that HSP70 expression is positively correlated with eIF4G in tumor specimens from 25 HCC patients, in contrast to the adjacent non-tumorous tissues, and that both influence the survival of HCC patients. Mechanistically, this study indicates that HSP70 and eIF4G interact with each other in vitro. We further show that the HSP70–eIF4G interaction contributes to promoting cellular protein synthesis, enhancing cell proliferation, and inhibiting cell apoptosis. Collectively, this study reveals the pivotal role of HSP70–eIF4G interaction as an escape mechanism in HCC. Therefore, modulation of the HSP70–eIF4G interaction might be a potential novel therapeutic target of HCC treatment.

The Response of Rhodotorula mucilaginosa to Patulin Based on Lysine Crotonylation

Patulin (PAT) is a mycotoxin produced by some Penicillium, Aspergillus, and Byssochlamys species. Rhodotorula mucilaginosa is able to degrade PAT in vivo as well as in vitro, up till date, the process and molecular mechanism(s) involved patulin degradation still remains unknown. Protein lysine crotonylation (Kcr) plays an important role in regulating chromatin dynamics, gene expression, and metabolic pathways in mammals and eukaryotes. Investigation of the Kcr changes accompanying degradation of patulin in R. mucilaginosa were observed to investigate the mechanisms of patulin inhibition. Tandem mass tag (TMT) labeling and Kcro affinity enrichment, followed by high-resolution LC-MS/MS analysis, were used to perform quantitative lysine crotonylome analysis on R. mucilaginosa. Consequently, 1691 lysine crotonylation sites in 629 protein groups were identified, among which we quantified 1457 sites in 562 proteins. Among the quantified proteins, 79 and 46 crotonylated proteins were up-regulated and down-regulated, respectively. The differentially up expressed modified proteins were mainly involved in tricarboxylic acid cycle and gluconeogenic pathway. The differentially down expressed Kcr proteins were mainly classified to ribosome and carbohydrate transport and metabolism. Bioinformatic analyses were performed to annotate the quantifiable lysine crotonylated targets. Moreover, interaction networks and high confidence domain architectures of crotonylated proteins were investigated with the aid of bioinformatic tools, and these results showed that there was an increase in the number of yeasts with crotonylated proteins. The results also provided information on the various roles of crotonylation, which are involved in PAT degradation.

Transformation of the Non-Selective Aminocyclohexanol-Based Hsp90 Inhibitor into a Grp94-Seletive Scaffold

Glucose regulated protein 94 kDa, Grp94, is the endoplasmic reticulum (ER) localized isoform of heat shock protein 90 (Hsp90) that is responsible for the trafficking and maturation of toll-like receptors, immunoglobulins, and integrins. As a result, Grp94 has emerged as a therapeutic target to disrupt cellular communication, adhesion, and tumor proliferation, potentially with fewer side effects compared to pan-inhibitors of all Hsp90 isoforms. Although, the N-terminal ATP binding site is highly conserved among all four Hsp90 isoforms, recent cocrystal structures of Grp94 have revealed subtle differences between Grp94 and other Hsp90 isoforms that has been exploited for the development of Grp94-selective inhibitors. In the current study, a structure-based approach has been applied to a Grp94 nonselective compound, SNX 2112, which led to the development of 8j (ACO1), a Grp94-selective inhibitor that manifests ∼440 nM affinity and >200-fold selectivity against cytosolic Hsp90 isoforms.

Comparative proteomic profiling and possible toxicological mechanism of acute injury induced by carbon ion radiation in pubertal mice testes

We investigated potential mechanisms of acute injury in pubertal mice testes after exposure to carbon ion radiation (CIR). Serum testosterone was measured following whole-body irradiation with a 2Gy carbon ion beam. Comparative proteomic profiling and Western blotting were applied to identify potential biomarkers and measure protein expression, and terminal dUTP nick end-labeling (TUNEL) was performed to detect apoptotic cells. Immunohistochemistry and immunofluorescence were used to investigate protein localization. Serum testosterone was lowest at 24h after CIR, and 10 differentially expressed proteins were identified at this time point that included eIF4E, an important regulator of initiation that combines with mTOR and 4EBP1 to control protein synthesis via the mTOR signaling pathway during proliferation and apoptosis. Protein expression and localization studies confirmed their association with acute injury following exposure to CIR. These three proteins may be useful molecular markers for detecting abnormal spermatogenesis following exposure to environmental and therapeutic radiation.

A member of the HSP90 family from ovine Babesia in China: molecular characterization, phylogenetic analysis and antigenicity

Heat shock protein 90 (HSP90) is a key component of the molecular chaperone complex essential for activating many signalling proteins involved in the development and progression of pathogenic cellular transformation. A Hsp90 gene (BQHsp90) was cloned and characterized from Babesia sp. BQ1 (Lintan), an ovine Babesia isolate belonging to Babesia motasi-like group, by screening a cDNA expression library and performing rapid amplification of cDNA ends. The full-length cDNA of BQHsp90 is 2399 bp with an open reading frame of 2154 bp encoding a predicted 83 kDa polypeptide with 717 amino acid residues. It shows significant homology and similar structural characteristics to Hsp90 of other apicomplex organisms. Phylogenetic analysis, based on the HSP90 amino acid sequences, showed that the Babesia genus is clearly separated from other apicomplexa genera. Five Chinese ovine Babesia isolates were divided into 2 phylogenetic clusters, namely Babesia sp. Xinjiang (previously designated a new species) cluster and B. motasi-like cluster which could be further divided into 2 subclusters (Babesia sp. BQ1 (Lintan)/Babesia sp. Tianzhu and Babesia sp. BQ1 (Ningxian)/Babesia sp. Hebei). Finally, the antigenicity of rBQHSP90 protein from prokaryotic expression was also evaluated using western blot and enzyme-linked immunosorbent assay (ELISA).

Development of radamide analogs as Grp94 inhibitors

Hsp90 isoform-selective inhibition is highly desired as it can potentially avoid the toxic side-effects of pan-inhibition. The current study developed selective inhibitors of one such isoform, Grp94, predicated on the chimeric and pan-Hsp90 inhibitor, radamide (RDA). Replacement of the quinone moiety of RDA with a phenyl ring (2) was found to be better suited for Grp94 inhibition as it can fully interact with a unique hydrophobic pocket present in Grp94. An extensive SAR for this scaffold showed that substitutions at the 2- and 4-positions (8 and 27, respectively) manifested excellent Grp94 affinity and selectivity. Introduction of heteroatoms into the ring also proved beneficial, with a 2-pyridine derivative (38) exhibiting the highest Grp94 affinity (K(d)=820 nM). Subsequent cell-based assays showed that these Grp94 inhibitors inhibit migration of the metastatic breast cancer cell line, MDA-MB-231, as well as exhibit an anti-proliferative affect against the multiple myeloma cell line, RPMI 8226.

Immunostimulatory effects of Leishmania infantum HSP70 recombinant protein on dendritic cells in vitro and in vivo

Background: Activation of dendritic cells (DCs) has an important role in immunity against Leishmania. Aim: We investigated the effect of Leishmania infantum (L. infantum) heat shock protein 70 recombinant protein (rHSP70) as a vaccine on DC maturation and function. Materials & methods: BALB/c mouse splenic DCs were isolated and treated with different concentrations of rHSP70. Maturation markers, cytokine production and capability of DCs to proliferate allogeneic T cells were evaluated. Furthermore, this recombinant protein was injected into BALB/c mice, and expression of CD86, CD40 and MHC class II molecules by their splenic DCs were evaluated. Results: rHSP70 significantly increases the production of IL-12p70 by DCs. It had no effect on allogeneic T-cell proliferation in mixed lymphocyte reaction. It increased IFN-γ and decreased IL-4 cytokine level in mixed lymphocyte reaction supernatant. The in vitro study showed that rHSP70 had no significant effect neither on the percentage of CD40+, CD86+ and MHC class II+ DCs nor on the mean fluorescent intensity. However, in vivo results showed that rHSP70 increases the percentage of CD86-, CD40- and MHC class II-expressing cells as well as mean fluorescent intensity of CD40 and MHC class II. Conclusion: This study demonstrated the capability of L. infantum-derived rHSP70 in maturating BALB/c mice splenic DCs and in vivo polarization of immunity to a Th1 response.

Plant heat shock protein 90 as carrier-adjuvant for immunization against a reporter antigen

Here, we evaluated the modulation of the immune response induced by Hsp90 of Nicotiana benthamiana (NbHsp90.3) against the Maltose Binding Protein (MBP) as a reporter antigen. Equimolar quantities of recombinant proteins were administered in mice as follows: MBP alone (MBP group), a mixture of MBP and rNbHsp90.3 (MBP+rNbHsp90.3 group) and the fusion of MBP to rNbHsp90.3 (MBP-rNbHsp90.3 group). The covalent linkage between NbHsp90.3 and MBP to bring a fusion protein was essential to induce the strong specific antibody response with predominance of IgG2a. Eighty-four days after the first immunization, splenocyte proliferation from MBP-rNbHsp90.3-immunized mice was consistently higher than that from MBP and MBP+rNbHsp90.3 groups. In addition, splenocytes from MBP-rNbHsp90.3 immunized mice produced higher levels of IFN-γ than controls. Finally, both formulations with rNbHsp90.3 significantly enhanced the MHC class I expression levels, but only rNbHsp90.3 covalent bound to MBP induced a specific cellular immune response against MBP measured as increased percentage of CD8(+) T cells. Taken together, these results suggest that plant HSP90s could be incorporated as adjuvants in vaccines that require the generation of a Th1 response along with a CD8 cytotoxic cell response to confer immunity.

The 'peptidome' of tumour-derived chaperone-rich cell lysate anti-cancer vaccines reveals potential tumour antigens that stimulate tumour immunity

Tumour-derived chaperone-rich cell lysate (CRCL) when isolated from tumour tissue or when embedded with peptide antigens is a potent anti-cancer vaccine consisting of numerous chaperone/heat shock proteins, including the highly immunogenic Hsp70, Hsp90, glucose regulated protein 94, and calreticulin. We have previously documented that CRCL provides both a source of tumour antigens and danger signals triggering antigen presenting cell activation. In this report we describe the 'peptidome' of potential antigens extracted from CRCL prepared from a murine tumour. Using mass spectrometry techniques we identify almost 60 different proteins of origin for the CRCL peptides; we determine that the parental proteins come from essentially all parts of the cell, and are involved in a broad range of functions. Further in silico analysis demonstrates that the parental proteins are components of major signalling networks of vital importance for cancer cell survival, proliferation, and migration. In many instances the peptides identified possess amino acid sequences that would allow their putative binding and display by murine major histocompatibility complex class I and II molecules, and there are also predicted binding motifs for Hsp70-type chaperones. By mixing fractionated pools of peptides with antigen-free (normal liver) CRCL, we were able to reconstitute effective anti-tumour activity of the vaccine, showing that the peptides are indeed the major purveyors of CRCL vaccines' efficacy.

Is thioredoxin reductase involved in the defense against DNA fragmentation in varicocele?

We aimed to investigate the role of thioredoxin reductase (TR) and inducible heat shock protein 70 (iHsp70) and their relationship with sperm quality in varicocele (VAR) patients. Semen samples were obtained from 16 subfertile men diagnosed as VAR and 10 fertile men who applied to the Andrology Laboratory of Istanbul Medical Faculty of Istanbul University. The sperm TR and iHsp 70 expression levels were determined using Western blot analysis. The TR activity of the sperm was assayed spectrophometrically. The sperm quality was evaluated both by conventional sperm analysis and by a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) technique that assayed DNA-fragmented spermatozoa in semen samples. The percentage of TUNEL-positive spermatozoa in the VAR group (16.3%± 5.6%) was higher than that in the fertile group (5.5%± 1.9%). Significant inverse correlations were detected between the percentage of TUNEL-positive cells and both the concentration (r=-0.609; P=0.001) and motility (r=-0.550; P=0.004) of spermatozoa. Both the TR expression and activity were increased significantly in the VAR group (U=22.0; P=0.001 and U=33.5; P=0.012, respectively) as analyzed using the Mann-Whitney U Wilcoxon rank sum W test. Furthermore, significant positive correlations were found between TR expression and activity (r=0.406; P=0.040) and between TR expression and the percentage of TUNEL-positive cells (r=0.665; P=0.001). Sperm iHsp70 expression did not differ between the VAR and fertile groups. In conclusion, increased sperm TR expression might be a defense mechanism against apoptosis in the spermatozoa of men with VAR.

Hsp70 and HSF-1 expression is altered in the tissues of pigs transported for various periods of times

The aim of this study was to assess changes of Hsp70 and HSF-1 protein and mRNA expression in stress-sensitive organs of pigs during transportation for various periods of time. Twenty pigs were randomly divided into four groups (0 h, 1 h, 2 h, and 4 h of transportation). A significant increased activity of AST and CK was observed after 1 h and 2 h of transportation. Histopathological changes in the heart, liver, and stomach indicated that these organs sustained different degrees of injury. Hsp70 protein expression in the heart and liver of transported pigs did not change significantly while it increased significantly (p < 0.05) in the stomach. Hsp70 mRNA levels decreased significantly (p < 0.05) in the heart after 4 h of transportation. However, mRNA expression increased significantly in the liver after 1 (p < 0.05) and 4 h (p < 0.01) of transportation, and increased significantly in the stomach of the transported pigs after 1, 4 (p < 0.01), and 2 h (p < 0.05). HSF-1 levels were reduced at 1 and 4 h (p < 0.05) only in the hearts of transported pigs. These results indicate that Hsp70 mediates distinct stress-related functions in different tissues during transportation.

Hsp110 expression changes in rat primary myocardial cells exposed to heat stress in vitro

We investigated and described the kinetics of heat shock protein (Hsp) 110 expression and distribution in rat primary myocardial cells exposed to heat stress in vitro. After incubation at 37°C for 72 h, myocardial cells were heat stressed at 42°C for 0, 10, 20, 40, 60, 120, 240, 360, and 480 min. Significant increases in aspartate transaminase, lactate dehydrogenase, and creatine kinase enzymatic activities in the myocardial cell culture media were observed during heat stress, suggesting that the integrity of the myocardial cells was altered. Immunocytochemical analysis revealed that the expressed Hsp110 was constitutively localized in the cytoplasm and in the nuclei in small amounts characterized by a granular pattern. Nuclear Hsp110 levels increased significantly after 240 min of heat stress compared with levels in the control. The overall levels of Hsp110 expression increased significantly after 20 min. After 240 min, Hsp110 levels were approximately 1.2-fold higher than those in the control. Increasing levels of hsp110 messenger RNA detected using real-time quantitative polymerase chain reaction were observed after 20 min of heat stress, and the levels peaked with a 10-fold increase after 240 min of heat stress. These results indicate that the expression of Hsp110 in primary myocardial cells in vitro is sensitive to hyperthermic stress and that Hsp110 is involved in the potential acquisition of thermotolerance after heat stress. Therefore, Hsp110 might play a fundamental role in opposing and alleviating heat-induced damage caused by hyperthermic stress in primary myocardial cells.

The dual behavior of heat shock protein 70 and asymmetric dimethylarginine in relation to serum CRP levels in type 2 diabetes

BACKGROUND

Experimental evidence suggests that heat shock proteins (HSP) and asymmetric dimethylarginine (ADMA) are induced in the state of chronic inflammation and stress conditions. They are both inhibitors of nitric oxide synthase (NOS). The aim of this study was to evaluate the correlation between ADMA and HSP70, in patients with type 2 diabetes with respect to serum levels of C reactive protein (CRP).

METHODS

We quantified serum HSP70, ADMA and CRP in 80 newly-diagnosed patients with type 2 diabetes plus 80 age-, sex and BMI-matched healthy controls. The patients and controls were also stratified into groups of high and low CRP levels (cut-point: 2.5mg/ml).

RESULTS

Patients with type 2 diabetes had significantly higher serum HSP70 (0.52 [0.51-0.66] vs. 0.27 [0.26-0.36], p<0.001), ADMA (0.86 [0.81-0.92] vs. 0.72 [0.71-0.85], p<0.05) and CRP (2.9 [1.7-3.4] vs. 1.6[1.2-2.3], p<0.05) compared with healthy controls. Serum HSP70 and ADMA levels were significantly correlated in patients with high CRP levels (r=0.89, p<0.01), whereas there were no correlation in patients with low CRP (r=-0.37, p=0.07) and controls. This correlation was significant (r=0.77, p<0.001) in patients with high CRP and also in patients with low CRP levels (r=-0.51, p<0.05), after multiple adjustments for LDL and HDL levels.

DISCUSSION

We showed that, in a state of high inflammation; serum levels of ADMA parallel the HSP70 levels. However in low inflammation, they are negatively correlated. The duality in HSP70 and ADMA correlation may be related to the duality of NOS function in low and high CRP levels.

Antitumor activity of mixed heat shock protein/peptide vaccine and cyclophosphamide plus interleukin-12 in mice sarcoma

Background

The immune factors heat shock protein (HSP)/peptides (HSP/Ps) can induce both adaptive and innate immune responses. Treatment with HSP/Ps in cancer cell-bearing mice and cancer patients revealed antitumor immune activity. We aimed to develop immunotherapy strategies by vaccination with a mixture of HSP/Ps (mHSP/Ps, HSP60, HSP70, Gp96 and HSP110) enhanced with cyclophosphamide (CY) and interleukin-12 (IL-12).

Methods

We extracted mHSP/Ps from the mouse sarcoma cell line S180 using chromatography. The identity of proteins in this mHSP/Ps was assayed using SDS-PAGE and Western blot analysis with antibodies specific to various HSPs. BALB/C mice bearing S180 cells were vaccinated with mHSP/Ps ×3, then were injected intraperitoneally with low-dose CY and subcutaneously with IL-12, 100 μg/day, ×5. After vaccination, T lymphocytes in the peripheral blood were analyzed using FACScan and Cytotoxicity (CTL) was analyzed using lactate dehydrogenase assay. ELISPOT assay was used to evaluate interferon γ (IFN-γ), and immune cell infiltration in tumors was examined in the sections of tumor specimen.

Results

In mice vaccinated with enhanced vaccine (mHSP/Ps and CY plus IL-12), 80% showed tumor regression and long-term survival, and tumor growth inhibition rate was 82.3% (30 days), all controls died within 40 days. After vaccination, lymphocytes and polymorphonuclear leukocytes infiltrated into the tumors of treated animals, but no leukocytes infiltrated into the tumors of control mice. The proportions of natural killer cells, CD8+, and interferon-γ-secreting cells were all increased in the immune group, and tumor-specific cytotoxic T lymphocyte activity was increased.

Conclusions

In this mice tumor model, vaccination with mHSP/Ps combined with low-dose CY plus IL-12 induced an immunologic response and a marked antitumor response to autologous tumors. The regimen may be a promising therapeutic agent against tumors.

Role of heat shock proteins in diseases and their therapeutic potential

Heat shock proteins are ubiquitously expressed intracellular proteins and act as molecular chaperones in processes like protein folding and protein trafficking between different intracellular compartments. They are induced during stress conditions like oxidative stress, nutritional deficiencies and radiation. They are released into extracellular compartment during necrosis. However, recent research findings highlights that, they are not solely present in cytoplasm, but also released into extracellular compartment during normal conditions and even in the absence of necrosis. When present in extracellular compartment, they have been shown to perform various functions like antigen presentation, intercellular signaling and induction of pro-inflammatory cytokines. Heat shock proteins represents as dominant microbial antigens during infection. The phylogenetic similarity between prokaryotic and eukaryotic heat shock proteins has led to proposition that, microbial heat shock proteins can induce self reactivity to host heat shock proteins and result in autoimmune diseases. The self-reactivity of heat shock proteins protects host against disease by controlling induction and release of pro-inflammatory cytokines. However, antibodies to self heat shock proteins haven been implicated in pathogenesis of autoimmune diseases like arthritis and atherosclerosis. Some heat shock proteins are potent inducers of innate and adaptive immunity. They activate dendritic cells and natural killer cells through toll-like receptors, CD14 and CD91. They play an important role in MHC-antigen processing and presentation. These immune effector functions of heat shock proteins are being exploited them as therapeutic agents as well as therapeutic targets for various infectious diseases and cancers.

Variation in the expression of Hsp27, αB-crystallin mRNA and protein in heart and liver of pigs exposed to different transport times

Twenty pigs were randomly divided into four groups of five pigs each (not transported - control, 1, 2 and 4h of transportation). A significant increase of ALT, AST and CK in the blood serum and acute parenchyma cell lesions were observed and those were characterized by acute degenerations in the heart and liver. Hsp27 expression levels increased significantly in the heart after 2h and in the liver after 4h of transportation, accompanying with the hsp27 mRNA increasing significantly in the heart and liver after 1h of transportation. αB-crystallin expression levels were fluctuant (not significantly) in the heart and liver during transporting, however, αB-crystallin mRNA increase notably in the heart after 1h and decrease significantly in the liver at 1 and 2h of transportation, respectively. In conclusion, the cellular damage to the heart and liver is highest after 1h of transportation, Hsp27 and αB-crystallin play dissimilar roles and show tissue-specific response in different tissues during transportation.

Proteomic analyses of the effects of drugs of abuse on monocyte-derived mature dendritic cells

Drug abuse has become a global health concern. Understanding how drug abuse modulates the immune system and how the immune system responds to pathogens associated with drug abuse, such hepatitis C virus (HCV) and human immunodeficiency virus (HIV-1), can be assessed by an integrated approach comparing proteomic analyses and quantitation of gene expression. Two-dimensional (2D) difference gel electrophoresis was used to determine the molecular mechanisms underlying the proteomic changes that alter normal biological processes when monocyte-derived mature dendritic cells were treated with cocaine or methamphetamine. Both drugs differentially regulated the expression of several functional classes of proteins including those that modulate apoptosis, protein folding, protein kinase activity, and metabolism and proteins that function as intracellular signal transduction molecules. Proteomic data were validated using a combination of quantitative, real-time PCR and Western blot analyses. These studies will help to identify the molecular mechanisms, including the expression of several functionally important classes of proteins that have emerged as potential mediators of pathogenesis. These proteins may predispose immunocompetent cells, including dendritic cells, to infection with viruses such as HCV and HIV-1, which are associated with drug abuse.

Heat shock protein 60 causes osteoclastic bone resorption via toll-like receptor-2 in estrogen deficiency

Estrogen deficiency leads to marked increases in osteoclastic bone resorption, but the exact mechanism is unclear. Proteomic analysis was performed on the femur and tibia of ovariectomy (OVX) and sham-operated Sprague-Dawley rats using two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometer (MS). Among the nine proteins differentially expressed between OVX and sham-operated rats, heat shock protein 60 (HSP60) was upregulated by 2.6-fold in the bones of OVX rats, and the plasma concentration of HSP60 was also significantly increased in OVX rats. Estrogen deficiency increases in secretions of interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha in T cell and osteoclasts (OCs) lineages, IL-1beta and TNF-alpha stimulated the production and secretion of HSP60 from OCs lineages. IL-1 receptor antagonist (ra), TNF-blocking antibody (Ab), and estradiol (E(2)) significantly suppressed the OVX-induced increase in plasma concentrations of HSP60 in mice. HSP60 potentiated OC formation and bone resorption, and pretreatment with HSP60-blocking Ab markedly reduced the potentiation of OC formation and bone resorption by IL-1beta- and TNF-alpha. HSP60 upregulated the expression levels of toll-like receptor (TLR)-2 in bone marrow macrophage (BMMvarphi), and pretreatment with a TLR-2-blocking Ab almost completely inhibited HSP60- or cytokine-induced potentiation of OC formation and/or bone resorption. In conclusion, HSP60 and TLR-2 are novel mediators of estrogen-deficiency-induced bone loss.

Increased circulating heat shock protein 60 induced by menopause, stimulates apoptosis of osteoblast-lineage cells via up-regulation of toll-like receptors

Postmenopausal osteoporosis is a heterogeneous disorder characterized by accelerated bone loss after natural or surgical menopause and an increased risk of fractures. The bone loss in estrogen deficiency results from the increased bone resorption and impaired ability of osteoblastic bone formation. Previous studies have reported that the HSP60 stimulates osteoclast formation and bone resorption. Here we found that plasma HSP60 levels were significantly higher in postmenopausal (median 1152.4 ng/ml; range 724.7-2123.4 ng/ml) than in premenopausal (median 316.3 ng/ml; range 164.6-638.4 ng/ml) women. In primary human bone marrow stromal cells (hBMSC) and the HS-5 hBMSC cell line, HSP60 significantly reduced cell viability and increased caspase-dependent apoptosis. Consistent with these observations, HSP60 activated caspase-3 and -9, but not caspase-8 in HS-5 cells, and increased the release of mitochondrial cytochrome c into the cytosol. In addition, HSP60 activated p38 and NFkappaB, but not ERK or JNK; importantly, inhibitors of p38 (SB203580) and NFkappaB (PDTC) abolished HSP60-induced apoptosis. Furthermore, Western blotting showed that HSP60 up-regulated TLR-2 and TLR-4 expression, and pretreatment with blocking antibodies for TLR-2 and TLR-4 almost completely eliminated the effects of HSP60 on apoptosis, caspase-3 and -9 activation, and activation of NFkappaB and p38 MAPK. Most notably, ovariectomy-induced bone loss was attenuated in TLR-2 KO mice. In conclusion, up-regulation of TLR-2 by HSP60 may play a critical role in promoting bone loss in the estrogen-deficient state.

Modulation of the proteome of peripheral blood mononuclear cells from HIV-1-infected patients by drugs of abuse

INTRODUCTION

We used proteomic analyses to assess how drug abuse modulates immunologic responses to infections with the human immunodeficiency virus type 1 (HIV-1).

METHODS

Two-dimensional difference gel electrophoresis was utilized to determine changes in the proteome of peripheral blood mononuclear cells (PBMC) isolated from HIV-1-positive donors that occurred after treatment with cocaine or methamphetamine. Both drugs differentially regulated the expression of several functional classes of proteins. We further isolated specific subpopulations of PBMC to determine which subpopulations were selectively affected by treatment with drugs of abuse. Monocytes, B cells, and T cells were positively or negatively selected from PBMC isolated from HIV-1-positive donors.

RESULTS

Our results demonstrate that cocaine and methamphetamine modulate gene expression primarily in monocytes and T cells, the primary targets of HIV-1 infection. Proteomic data were validated with quantitative, real-time polymerase chain reaction. These studies elucidate the molecular mechanisms underlying the effects of drugs of abuse on HIV-1 infections. Several functionally relevant classes of proteins were identified as potential mediators of HIV-1 pathogenesis and disease progression associated with drug abuse.

Thermotolerance and HSP70 expression in the Mediterranean fruit fly Ceratitis capitata

The relationship between Hsp70 expression and thermotolerance has been well documented in Drosophila melanogaster. However, there is limited information on this relationship in other insect species. In this report we describe the Hsp70-thermotolerance relationship in one of the major fruit fly pests, Ceratitis capitata (medfly). Hsp70 expression and thermotolerance were assayed at a range of temperatures in several stages of medfly development. The most thermotolerant stage was found to be the late larval stage (100% survival at 41 degrees C) followed by adult flies and late embryos (100% survival at 39 degrees C). These three stages showed a positive relationship between Hsp70 expression and thermotolerance. Mid-larval and mid-embryonic stages were found less thermotolerant and the Hsp70-thermotolerance relationship was not evident. Early embryos did not express Hsp70 at any temperature and exhibited the lowest thermotolerance. The relationship between Hsp70 and inducible thermotolerance was also studied in late larvae. A pretreatment at 37-39 degrees C increased thermotolerance at higher temperatures by approximately 1 degrees C. In parallel, the pretreatment increased Hsp70 expression suggesting a close link between Hsp70 expression and inducible thermotolerance. The increased Hsp70 levels after pretreatment were found to be due to the increased levels of the hsp70 RNA.

Use of ultraviolet-light irradiated multiple myeloma cells as immunogens to generate tumor-specific cytolytic T lymphocytes

Background

As the eradication of tumor cells in vivo is most efficiently performed by cytolytic T lymphocytes (CTL), various methods for priming tumor-reactive lymphocytes have been developed. In this study, a method of priming CTLs with ultraviolet (UV)-irradiated tumor cells, which results in termination of tumor cell proliferation, apoptosis, as well as upregulation of heat shock proteins (HSP) expression is described.

Methods

Peripheral blood mononuclear cells (PBMC) were primed weekly with UV-irradiated or mitomycin-treated RPMI 8226 multiple myeloma cells. Following three rounds of stimulation over 21 days, the lymphocytes from the mixed culture conditions were analyzed for anti-MM cell reactivity.

Results

By day 10 of cultures, PBMCs primed using UV-irradiated tumor cells demonstrated a higher percentage of activated CD8+/CD4- T lymphocytes than non-primed PBMCs or PBMCs primed using mitomycin-treated MM cells. Cytotoxicity assays revealed that primed PBMCs were markedly more effective (p < 0.01) than non-primed PBMCs in killing RPMI 8226 MM cells. Surface expression of glucose regulated protein 94 (Grp94/Gp96) and Grp78 were both found to be induced in UV-treated MM cells.

Conclusion

Since, HSP-associated peptides are known to mediate tumor rejection; these data suggest that immune-mediated eradication of MM cells could be elicited via a UV-induced HSP process. The finding that the addition of 17-allylamide-17-demethoxygeldanamycin (17AAG, an inhibitor of HSP 90-peptide interactions) resulted in decreased CTL-induced cytotoxicity supported this hypothesis. Our study, therefore, provides the framework for the development of anti-tumor CTL cellular vaccines for treating MM using UV-irradiated tumor cells as immunogens.

Allogeneic tumor-cell-based vaccines secreting endoplasmic reticulum chaperone gp96

Heat-shock proteins are chaperones for proteins including tumor antigens. Heat-shock protein gp96, also known as glucose-regulated protein grp94, is the primary chaperone of the endoplasmic reticulum and a natural adjuvant for priming the innate and adaptive immune system. By transfecting tumor cells with a genetically modified secretory form of gp96, the tumor cells are transformed into vaccine cells. Gp96 vaccines in murine studies trigger robust innate and antigen-specific cellular immune responses and cause tumor rejection followed by long-lasting tumor immunity. The authors briefly review here the generation of cytotoxic T lymphocyte responses by gp96 and the most up to date clinical data in the use of gp96-based cancer vaccines.

Heat shock protein derivatives for delivery of antigens to antigen presenting cells

Delivery of antigens to antigen presenting cells (APCs) is a key issue for developing effective cancer vaccines. Controlling the tissue distribution of antigens can increase antigen-specific immune responses, including the induction of cytotoxic T lymphocytes (CTL). Heat shock protein 70 (Hsp70) forms complexes with a variety of tumor-related antigens via its polypeptide-binding domain. Because Hsp70 is taken up by APCs through recognition by Hsp receptors, such as CD91 and LOX-1, its application to antigen delivery systems has been examined both in experimental and clinical settings. A tissue distribution study revealed that Hsp70 is mainly taken up by the liver, especially by hepatocytes, after intravenous injection in mice. A significant amount of Hsp70 was also delivered to regional lymph nodes when it was injected subcutaneously, supporting the hypothesis that Hsp70 is a natural targeting system for APCs. Model antigens were complexed with or conjugated to Hsp70, resulting in greater antigen-specific immune responses. Cytoplasmic delivery of Hsp70-antigen further increased the efficacy of the Hsp70-based vaccines. These findings indicate that effective cancer therapy can be achieved by developing Hsp70-based anticancer vaccines when their tissue and intracellular distribution is properly controlled.

The role of heat shock protein 70 (Hsp 70) in male infertility: is it a line of defense against sperm DNA fragmentation?

OBJECTIVE

To clarify the role of heat shock protein 70 (Hsp 70) and its relation with DNA damage in male infertility.

DESIGN

Prospective study.

SETTING

Andrology laboratory of Istanbul Medical Faculty.

PATIENT(S)

Semen samples from 37 infertile men and 13 fertile men (as controls).

INTERVENTION(S)

The percentage of DNA fragmentation was assayed with the use of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL). Sperm Hsp 70 expression was determined by using Western blot analysis.

MAIN OUTCOME MEASURE(S)

Both the percentages of sperm DNA fragmentation and Hsp 70 expression were correlated with semen analysis parameters.

RESULTS

TUNEL-positive spermatozoa in the infertile group (18.7% for asthenospermics and 13.0% for oligoasthenospermics) were higher than the fertile group (4.9%). Significant inverse correlations were detected between percentage of TUNEL-positive cells and both concentration (r = -0.487) and motility (r = -0.377) of spermatozoa. No expression of Hsp 70 was observed in azospermic group, whereas Hsp 70 levels were found increased significantly in infertile group (U = 62 for asthenospermics and U = 38 for oligoasthenospermics) compared to fertile group as analyzed by using Mann-Whitney U Wilcoxon rank sum test. Furthermore, significant positive correlation was found between percentage of TUNEL-positive cells and Hsp 70 expression (r = 0.357).

CONCLUSION(S)

Hsp 70 expression may have been increased as a protective mechanism against apoptosis in spermatozoa of infertile men.

Identification of new subgroup of HSP70 in Bythograeidae (hydrothermal crabs) and Xanthidae

Crabs of the Bythograeidae family (Crustacea: Brachyura: Bythogreoidea) are the only endemic crab family living in hydrothermal fields. The hydrothermal environment is characterized by unique ecological parameters, such as the high temperature gradient around the hydrothermal chimney (2-350 degrees C), a fluid environment containing high levels of metals and numerous gases. The 70-kDa Heat Shock Protein (HSP70) group is the most-studied HSP, because it is ubiquitous, and a strong positive correlation has been found between the amounts of HSP70 produced in response to stress, and the ability of the organism to withstand stressful conditions. The 70-kDa heat shock protein genes from Bythograeids (species analyzed: Bythograea thermydron, Cyanagraea praedator and Segonzacia mesatlantica) were characterized. Our results revealed that Bythograeidae possess genes which are similar with those present in Xanthids (coastal crabs). The deduced protein sequences displayed motifs distinct from those in the other crustacean HSC70/HSP70s available in the databases. Phylogenetic analysis showed that these members of HSP70 family identified in Bythograeidae and Xanthidae constitute a new subgroup within this family.

Innate immunity, assessed by plasma NO measurements, is not suppressed during the incubation fast in eiders

Immunity is hypothesized to share limited resources with other physiological functions and may mediate life history trade-offs, for example between reproduction and survival. However, vertebrate immune defense is a complex system that consists of three components. To date, no study has assessed all of these components for the same animal model and within a given situation. Previous studies have determined that the acquired immunity of common eiders (Somateria mollissima) is suppressed during incubation. The present paper aims to assess the innate immune response in fasting eiders in relation to their initial body condition. Innate immunity was assessed by measuring plasma nitric oxide (NO) levels, prior to and after injection of lipopolysaccharides (LPS), a method which is easily applicable to many wild animals. Body condition index and corticosterone levels were subsequently determined as indicators of body condition and stress level prior to LPS injection. The innate immune response in eiders did not vary significantly throughout the incubation period. The innate immune response of eiders did not vary significantly in relation to their initial body condition but decreased significantly when corticosterone levels increased. However, NO levels after LPS injection were significantly and positively related to initial body condition, while there was a significant negative relationship with plasma corticosterone levels. Our study suggests that female eiders preserve an effective innate immune response during incubation and this response might be partially determined by the initial body condition.

Heat shock proteins as vaccine adjuvants in infections and cancer

In addition to maintaining cell homeostasis under physiological and stress conditions, some heat shock proteins (HSPs) are potent inducers of immunity and have been harnessed as vaccine adjuvants targeted to cancers and infections. HSPs are a group of ubiquitous intracellular molecules that function as molecular chaperones in numerous processes, such as protein folding and transport, and are induced under stress conditions, such as fever and radiation. Certain HSPs are potent inducers of innate and antigen-specific immunity. They activate dendritic cells partly through toll-like receptors, activate natural killer cells, increase presentation of antigens to effector cells and augment T-cell and humoral immune responses against their associated antigens. Their roles in priming multiple host defense pathways are being exploited in vaccine development for cancer and infectious diseases.

Promoter of the heat shock testis-specific Hsp70.2/Hst70 gene is active in nervous system during embryonic development of mice

The Hsp70.2/Hst70 gene is a unique member of the 70 kDa heat shock proteins multigene family whose activity is regulated developmentally; in adult mice and rats its expression is restricted mostly to meiotic and postmeiotic male germ cells. In aim to analyze activity of the Hsp70.2/Hst70 promoter in developing embryos we have constructed transgenic mice expressing EGFP reporter gene under control of the rat Hst70 promoter. The appearance of EGFP fluorescence coincides with series of major developmental events, such as extra-embryonic membranes formation, axial rotation, formation of neural tube and the primordium of central nervous system, formation of differentiated somites, extensive remodeling of the heart, development of fingers and toes, and sensory organs formation. Activity of the Hst70 promoter localizes mostly inside nervous system indicating the role of Hsp70.2/Hst70 gene in development of this system.

Proteomic analysis of the effects of cocaine on the enhancement of HIV-1 replication in normal human astrocytes (NHA)

The US is experiencing an epidemic of cocaine use entangled with HIV-1 infection. Normal human astrocytes (NHA) are susceptible to HIV-1 infection. We utilized LTR-R/U5 amplification, p24 antigen assay and the proteomic method of difference gel electrophoresis (DIGE) combined with protein identification through HPLC-MS/MS to investigate the effect of cocaine on HIV-1 infectivity and the proteomic profile of NHA, respectively. Data demonstrate that cocaine significantly upregulates HIV-1 infection in NHA as measured by LTR-R/U5 amplification and p24 antigen assay. Further, our results show for the first time that cocaine differentially regulates the expression of a number of proteins by NHA that may play a role in the neuropathogenesis of HIV-1 disease.

Spinal cord injury induced heat shock protein expression is reduced by an antioxidant compound H-290/51. An experimental study using light and electron microscopy in the rat

The possibility that oxidative stress participates in heat shock protein 72 kD (HSP 72) expression following a focal trauma to the spinal cord was examined using a potent antioxidant compound H-290/51 in a rat model. A focal spinal cord injury (SCI) inflicted by making a longitudinal incision on the right dorsal horn of the T10-T11 segment under equithesin anaesthesia resulted in profound upregulation of HSP 72 expression in the adjacent spinal cord segments T9 and T12. This expression of HSP was most marked in the ipsilateral cord at 5 h after SCI. Pretreatment with H-290/51 (50 mg/kg, p.o.) 30 min before SCI markedly attenuated HSP expression in the spinal cord seen at 5 h. The motor functions of traumatized rats were also improved in the drug treated group. At this time, structural changes in the spinal cord and edema formation were considerable reduced compared to the untreated traumatized rats. Taken together, these observations suggest that (i) oxidative stress participates in HSP response following trauma, and (ii) the antioxidant compound H-290/51 attenuates cellularstress, improves motor functions and induces considerable neuroprotection in the early phase of SCI. Further studies using post-injury treatment with H-290/51 is needed to explore its therapeutic potentials in clinical settings.

Structural determinants of HscA peptide-binding specificity

The Hsp70-class molecular chaperone HscA interacts specifically with a conserved (99)LPPVK(103) motif of the iron-sulfur cluster scaffold protein IscU. We used a cellulose-bound peptide array to perform single-site saturation substitution of peptide residues corresponding to Glu(98)-Ile(104) of IscU to determine positional amino acid requirements for recognition by HscA. Two mutant chaperone forms, HscA(F426A) with a DnaK-like arch structure and HscA(M433V) with a DnaK-like substrate-binding pocket, were also studied. Wild-type HscA and HscA(F426A) exhibited a strict preference for proline in the central peptide position (ELPPVKI), whereas HscA(M433V) bound a peptide containing a Pro-->Leu substitution at this location (ELPLVKI). Contributions of Phe(426) and Met(433) to HscA peptide specificity were further tested in solution using a fluorescence-based peptide-binding assay. Bimane-labeled HscA and HscA(F426A) bound ELPPVKI peptides with higher affinity than leucine-substituted peptides, whereas HscA(M433V) favored binding of ELPLVKI peptides. Fluorescence-binding studies were also carried out with derivatives of the peptide NRLLLTG, a model substrate for DnaK. HscA and HscA(F426A) bound NRLLLTG peptides weakly, whereas HscA(M433V) bound NRLLLTG peptides with higher affinity than IscU-derived peptides ELPPVKI and ELPLVKI. These results suggest that the specificity of HscA for the LPPVK recognition sequence is determined in part by steric obstruction of the hydrophobic binding pocket by Met(433) and that substitution with the Val(433) sidechain imparts a broader, more DnaK-like, substrate recognition pattern.

Human serum contains detectable levels of the Hsp70 cochaperone HspBP1 and antibodies bound to HspBP1

The identification of the proteins that comprise the serum proteome is a current major research goal that will provide useful information for the diagnosis and treatment of various diseases. It is well established that Hsp70 and Hsp70 antibodies are present in human serum. This study reports on the development of an ELISA assay for the Hsp70 co-chaperone, HspBP1. HspBP1 is present in human serum at concentrations ranging between 0.74 to 3.98 ng/mL. No gender or age differences in the HspBP1 levels were identified. It was also found that human serum contained antibodies to HspBP1, and there were no gender or age differences in these levels. In addition, there was no correlation between the level of HspBP1 in a sample and the antibody titer. Finally, we found that HspBP1 in serum is complexed to anti-HspBP1 antibodies. This report provides initial baseline data on HspBP1 in human serum and provides the methods for future studies to determine if these levels are altered in response to disease.

Fasting-induced changes of immunological and stress indicators in breeding female eiders

One adaptive significance of immunosuppression during reproduction can be explained by the immunopathology-avoidance hypothesis. This hypothesis states that since heat shock proteins (HSP) are highly conserved proteins found in both pathogen and host, and are expressed at a higher level during reproduction, the risk of autoimmunity is then increased, HSP being the target of the host's immune response. Reduced immunocompetence has been attributed to hormonal regulation, in particular by glucocorticoids. The current study aimed at testing the immunopathology-avoidance hypothesis and the implication of corticosterone in incubating fasting common eiders (Somateria mollissima). To this end, we have measured immunological and stress indicators including immunoglobulin (IgY), HSP70, HSP60, and corticosterone levels in breeding females. A multivariate general linear model analysis showed that female body condition, IgY, HSP70, and HSP60 levels were the main variables explaining the model. Females showed a significant decrease by 15% of their IgY index during incubation. Conversely, HSP70 and HSP60 levels significantly increased by 12 and 10%, respectively throughout incubation. Moreover, there was a positive significant relationship between both HSP whereas HSP60 levels were negatively correlated to IgY index. Plasma corticosterone levels showed a tendency to decrease during incubation. We conclude that these findings are consistent with the immunopathology-avoidance hypothesis in breeding eiders. Nevertheless, the long-term reproductive costs and the underlying mechanisms of such an immunosuppression remain to be determined and will require further experiments.

Heat shock fusion protein induces both specific and nonspecific anti-tumor immunity

Mucin 1 (MUC1) is a tumor antigen, and the most important epitopes that can induce cytotoxic T lymphocytes (CTL) reside in the variable-number tandem repeats (VNTR). Heat shock protein (HSP) complexes isolated from tumors have been shown to induce specific anti-tumor immunity. HSP alone can also induce nonspecific immunity. To explore the possibility to utilize the specific anti-tumor immunity induced by MUC1 VNTR and the nonspecific immunity induced by HSP, we constructed a recombinant protein (HSP65-MUC1) by fusing Bacillus Calmette-Guérin-derived HSP65 with the MUC1 VNTR peptide and tested its ability to induce anti-tumor activities in a tumor challenge model. The growth of MUC1-expressing tumors was significantly inhibited in mice immunized with HSP65-MUC1, both before and after tumor challenge. A much larger percentage of immunized mice survived the tumor challenge than non-immunized mice. Correlating with the anti-tumor activity, HSP65-MUC1 was shown to induce MUC1-specific CTL as well as nonspecific anti-tumor immunity. In the human system, HSP65-MUC1-loaded human DC induced the generation of autologous MUC1-specific CTL in vitro. These results suggest that exogenously applied HSP65-MUC1 may be used to treat MUC1 tumors by inducing the epitope-specific CTL as well as nonspecific anti-tumor responses mediated by the HSP part of the fusion protein.

Heat Shock Protein–Based Cancer Vaccines

The ability to duplicate the remarkable success of infectious disease vaccines in cancer, with durably robust and highly specific antitumor immune responses, has been long held as one of the keys in developing true "magic bullet" cancer therapies. This article attempts to explain why cancer vaccines have failed (so far), delineate the increasingly complex barriers that prevent the eliciting of effective antitumor immunity and examines the ability of heat shock protein-based vaccines to overcome these barriers. This article is not a definitive compendium of the huge body of relevant literature but rather focuses on the major concepts underlying active specific immunotherapy in general and heat shock protein vaccines in particular.

Prophylactic, therapeutic and anti-metastatic effects of an HPV-16mE6Δ/mE7/TBhsp70Δ fusion protein vaccine in an animal model

Human papillomaviruses (HPVs), particularly HPV-16, are not only causally linked to cervical cancers but also play an important role in the development of other cancers. The oncoproteins, E6 and E7, are consistently coexpressed in the majority of HPV-containing carcinomas and their metastatic lesions, and are critical to the induction and maintenance of malignant phenotype, and also can cause tumor metastasis. Therefore, E6 and E7 represent ideal tumor-specific antigens for the development of immunotherapy to prevent and treat HPV-associated cancers and their metastases. The powerful antigenic nature of Mycobacterium tuberculosis heat shock protein 70 (TBhsp70) is emphasized by evidence that mammals are capable of recognizing murine and human multiple B and T cell epitopes in this protein, and therefore allows it to be used as an adjuvant-free carrier to stimulate the immune response to a covalently linked fusion partner. In our present study, we developed a recombinant TBhsp70Delta protein expression vector that permits the production of other protein fused to TBhsp70Delta. A recombinant HPV-16mE6Delta/mE7/TBhsp70Delta fusion protein was expressed and purified, and immunization with the fusion protein in the absence of adjuvant was capable of providing strong protection to C57BL/6 mice against challenge and rechallenge with TC-1 cells, but not HPV negative Lewis lung cancer cells, and induced established TC-1 tumor regression and led to long-term survival. Consistent with the in vivo results, the fusion protein immunization in the absence of adjuvant induced cytolytic T lymphocytes recognized specifically TC-1 tumor cells in vitro. We also demonstrated that immunization with the fusion protein in the absence of adjuvant was effective in both preventing and treating TC-1 metastatic lesions in the lung metastasis model. In particular, immunization with the fusion protein caused regression of established lung metastatic lesions in 50% of immunized animals. This study represents an instance of tumor therapy with a TBhsp70Delta fusion protein and provides the scientific basis for the clinical application of the HPV16mE6Delta/mE7/TBhsp70Delta fusion protein in the treatment of HPV-associated cancers and their metastases.

Thymic commitment of regulatory T cells is a pathway of TCR-dependent selection that isolates repertoires undergoing positive or negative selection

The seminal work of Le Douarin and colleagues (Ohki et al. 1987; Ohki et al. 1988; Salaun et al. 1990; Coutinho et al. 1993) first demonstrated that peripheral tissue-specific tolerance is centrally established in the thymus, by epithelial stromal cells (TEC). Subsequent experiments have shown that TEC-tolerance is dominant and mediated by CD4 regulatory T cells (Treg) that are generated intrathymically by recognition of antigens expressed on TECs (Modigliani et al. 1995; Modigliani et al. 1996a). From these and other observations, in 1996 Modigliani and colleagues derived a general model for the establishment and maintenance of natural tolerance (MM96) (Modigliani et al. 1996b), with two central propositions: (1) T cell receptor (TCR)-dependent sorting of emergent repertoires generates TEC-specific Treg displaying the highest TCR self-affinities below deletion thresholds, thus isolating repertoires undergoing positive and negative selection; (2) Treg are intrathymically committed (and activated) for a unique differentiative pathway with regulatory effector functions. The model explained the embryonic/perinatal time window of natural tolerance acquisition, by developmental programs determining (1) TCR multireactivity, (2) the cellular composition in the thymic stroma (relative abundance of epithelial vs hemopoietic cells), and (3) the dynamics of peripheral lymphocyte pools, built by accumulation of recent thymic emigrants (RTE) that remain recruitable to regulatory functions. We discuss here the MM96 in the light of recent results demonstrating the promiscuous expression of tissue-specific antigens by medullary TECs (Derbinski et al. 2001; Anderson et al. 2002; Gotter et al. 2004) and indicating that Treg represent a unique differentiative pathway (Fontenot et al. 2003; Hori et al. 2003; Khattri et al. 2003), which is adopted by CD4 T cells with high avidity for TEC-antigens (Bensinger et al. 2001; Jordan et al. 2001; Apostolou et al. 2002). In the likelihood that autoimmune diseases (AID) result from Treg deficits, some of which might have a thymic origin, we also speculate on therapeutic strategies aiming at selectively stimulating their de novo production or peripheral function, within recent findings on Treg responses to inflammation (Caramalho et al. 2003; Lopes-Carvalho et al., submitted, Caramalho et al., submitted). In short, the MM96 argued that natural tolerance is dominant, established and maintained by the activity of Treg, which are selected upon high-affinity recognition of self-ligands on TECs, and committed intrathymically to a unique differentiative pathway geared to anti-inflammatory and antiproliferative effector functions. By postulating the intrathymic deletion of self-reactivities on hemopoietic stromal cells (THC), together with the inability of peripheral resident lymphocytes to engage in the regulatory pathway, the MM96 simultaneously explained the maintenance of responsiveness to non-self in a context of suppression mediating dominant self-tolerance. The major difficulty of the MM96 is related to the apparent tissue specificity of Treg repertoires generated intrathymically. This difficulty has now been principally solved by the work of Hanahan, Kyewski and others (Jolicoeur et al. 1994; Derbinski et al. 2001; Anderson et al. 2002; Gotter et al. 2004), demonstrating the selective expression of a variety of tissue-specific antigens by TECs, in topological patterns that are compatible with the MM96, but difficult to conciliate with recessive tolerance models (Kappler et al. 1987; Kisielow et al. 1988). While the developmentally regulated multireactivity of TCR repertoires (Gavin and Bevan 1995), as well as the peripheral recruitment of Treg among RTE (Modigliani et al. 1996a) might add to this process, it would seem that the establishment of tissue-specific tolerance essentially stems from the "promiscuous expression of tissue antigens" by TEC. The findings of AID resulting from natural mutations (reviewed in Pitkanen and Peterson 2003) or the targeted inactivation (Anderson et al. 2002; Ramsey et al. 2002) of the AIRE transcription factor that regulates promiscuous gene expression on TECs support this conclusion. The observations on the correlation of natural or forced expression of the Foxp3 transcription factor in CD4 T cells with Treg phenotype and function (Fontenot et al. 2003; Hori et al. 2003; Khattri et al. 2003) provided support for the MM96 contention that Treg represent a unique differentiative pathway that is naturally established inside the thymus. Furthermore, Caton and colleagues (Jordan et al. 2001), as well as several other groups (Bensinger et al. 2001; Apostolou et al. 2002), have provided direct evidence for our postulate that Treg are selected among differentiating CD4 T cells with high affinity for ligands expressed on TECs (Modigliani et al. 1996b). Finally, the demonstration by Caramalho et al. that Treg express innate immunity receptors (Caramalho et al. 2003) and respond to pro-inflammatory signals and products of inflammation (Caramalho et al., submitted) brought about a new understanding on the peripheral regulation of Treg function. Together with the observation that Treg also respond to ongoing activities of "naïve/effector" T cells--possibly through the IL-2 produced in these conditions--these findings explain the participation of Treg in all immune responses (Onizuka et al. 1999; Shimizu et al. 1999; Annacker et al. 2001; Curotto de Lafaille et al. 2001; Almeida et al. 2002; Shevach 2002; Bach and Francois Bach 2003; Wood and Sakaguchi 2003; Mittrucker and Kaufmann 2004; Sakaguchi 2004), beyond their fundamental role in ensuring self-tolerance (e.g., Modigliani et al. 1996a; Shevach 2000; Hori et al. 2003; Sakaguchi 2004; Thompson and Powrie 2004). Thus, anti-inflammatory and anti-proliferative Treg are amplified by signals that promote or mediate inflammation and proliferation, accounting for the quality control of responses (Coutinho et al. 2001). In turn, such natural regulation of Treg by immune responses to non-self may well explain the alarming epidemiology of allergic and AID in wealthy societies (Wills-Karp et al. 2001; Bach 2002; Yazdanbakhsh et al. 2002), where a variety of childhood infections have become rare or absent. Thus, it is plausible that Treg were evolutionarily set by a given density of infectious agents in the environment. With hindsight, it is not too surprising that natural Treg performance falls once hygiene, vaccination, and antibiotics suddenly (i.e., 100 years) plunged infectious density to below some critical physiological threshold. As the immune system is not adapted to modern clean conditions of postnatal development, clinical immunologists must now deal with frequent Treg deficiencies (allergies and AID) for which they have no curative or rational treatments. It is essential, therefore, that basic immunologists concentrate on strategies to selectively stimulate the production, survival, and activity of this set of lymphocytes that is instrumental in preventing immune pathology. We have argued that the culprit of this inability of basic research to solve major clinical problems has been the self-righteousness of recessive tolerance champions, from Ehrlich to some of our contemporaries. It is ironical, however, that none of us--including the heretic opponents of horror autotoxicus--had understood that self-tolerance, or its robustness at least, is in part determined by the frequency and intensity of the responses to non-self. In the evolution of ideas on immunological tolerance, the time might be ripe for some kinds of synthesis. First, conventional theory reduced self-tolerance to negative selection and microbial defense to positive selection, while the MM96 solution was the precise opposite: positive selection of autoreactivities for self-tolerance (Treg) and negative selection (of Treg) for ridding responses. In contrast, it would now appear that positive and negative selection of autoreactive T cells are both necessary to establish either self-tolerance or competence to eliminate microbes, two processes that actually reinforce each other in the maintenance of self-integrity. Second, V-region recognition has generally been held responsible for specific discrimination between what should be either tolerated or eliminated from the organism. In contrast again, it would now seem that both processes of self-tolerance and microbial defense (self/non-self discrimination) also operate on the basis of evolutionarily ancient, germ-line-encoded innate, nonspecific receptors (Medzhitov and Janeway 2000) capable of a coarse level of self/non-self discrimination (Coutinho 1975). It could thus be interesting to revisit notions of cooperativity between V-regions and such mitogen receptors, both in single cell functions (Coutinho et al. 1974) and in the system's evolution (Coutinho 1975, 1980) as well. After all, major transitions in evolution were cooperative (Maynard-Smith and Szathmary 1995).

Loss of Hsp70 in Drosophila is pleiotropic, with effects on thermotolerance, recovery from heat shock and neurodegeneration

The heat-shock response is a programmed change in gene expression carried out by cells in response to environmental stress, such as heat. This response is universal and is characterized by the synthesis of a small group of conserved protein chaperones. In Drosophila melanogaster the Hsp70 chaperone dominates the profile of protein synthesis during the heat-shock response. We recently generated precise deletion alleles of the Hsp70 genes of D. melanogaster and have used those alleles to characterize the phenotypes of Hsp70-deficient flies. Flies with Hsp70 deletions have reduced thermotolerance. We find that Hsp70 is essential to survive a severe heat shock, but is not required to survive a milder heat shock, indicating that a significant degree of thermotolerance remains in the absence of Hsp70. However, flies without Hsp70 have a lengthened heat-shock response and an extended developmental delay after a non-lethal heat shock, indicating Hsp70 has an important role in recovery from stress, even at lower temperatures. Lack of Hsp70 also confers enhanced sensitivity to a temperature-sensitive lethal mutation and to the neurodegenerative effects produced by expression of a human polyglutamine disease protein.

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