Heat shock proteins gp96 and hsp70 activate the release of nitric oxide by APCs

Tumor-derived Hsp70-CD14 interaction enhances the antitumor potential of cytotoxic T cells by activating tumor-associated macrophages to express CC chemokines and CD40 costimulatory molecules

Heat shock proteins are a widely distributed group of proteins. It is constitutively expressed in almost all organisms and shows little variation throughout evolution. Previously, HSPs, particularly Hsp70, were recognized as molecular chaperones that aid in the proper three-dimensional folding of newly synthesized polypeptides in cells. Recently, researchers have focused on the potential induction of immune cells, including macrophages, antigen-specific CD8+ cytotoxic T cells, and PBMCs. It induces the expression of CC chemokines such as MIP-1α and RANTES, which are responsible for the chemotactic movement and migration of immune cells at the site of infection to neutralize foreign particles in vivo and in vitro in several cell lines but their effect on tumor-associated macrophages is still not known. These cytokines are also known to influence the movement of several immune cells, including CD8+ cytotoxic T cells, toward inflammatory sites. Therefore, the effect of tumor-derived autologous Hsp70 on the expression of MIP-lα and RANTES in tumor-associated macrophages (TAMs) was investigated. Our results indicated that Hsp70 treatment-induced MIP-lα and RANTES expression was significantly greater in TAMs than in NMOs. According to the literature, the CC chemokine shares the same receptor, CCR5, as HIV does for their action, and therefore could provide better completion to the virus for ligand binding. Furthermore, Hsp70-preactivated TAMs induced increased IL-2 and IFN-γ expression in T cells during coculture for 48 h and upregulated the antitumor immune response of the host. Therefore, the outcome of our study could be useful for developing a better approach to restricting the growth and progression of tumors.

Harnessing Hyperthermia: Molecular, Cellular, and Immunological Insights for Enhanced Anticancer Therapies

Hyperthermia, the raising of tumor temperature (≥39°C), holds great promise as an adjuvant treatment for cancer therapy. This review focuses on 2 key aspects of hyperthermia: its molecular and cellular effects and its impact on the immune system. Hyperthermia has profound effects on critical biological processes. Increased temperatures inhibit DNA repair enzymes, making cancer cells more sensitive to chemotherapy and radiation. Elevated temperatures also induce cell cycle arrest and trigger apoptotic pathways. Furthermore, hyperthermia modifies the expression of heat shock proteins, which play vital roles in cancer therapy, including enhancing immune responses. Hyperthermic treatments also have a significant impact on the body's immune response against tumors, potentially improving the efficacy of immune checkpoint inhibitors. Mild systemic hyperthermia (39°C-41°C) mimics fever, activating immune cells and raising metabolic rates. Intense heat above 50°C can release tumor antigens, enhancing immune reactions. Using photothermal nanoparticles for targeted heating and drug delivery can also modulate the immune response. Hyperthermia emerges as a cost-effective and well-tolerated adjuvant therapy when integrated with immunotherapy. This comprehensive review serves as a valuable resource for the selection of patient-specific treatments and the guidance of future experimental studies.

Combined effects of hypoxia and ammonia-N exposure on the immune response, oxidative stress, tissue injury and apoptosis of hybrid grouper (Epinephelus fuscoguttatus♀×E. lanceolatus♂)

In order to investigate the simultaneous exposure to hypoxia and ammonia-N on oxidative stress, immune response, and apoptosis of the hybrid grouper, 120 healthy groupers were selected for hypoxia and/or ammonia-N exposure experiment. The fish were divided into four experimental groups: hypoxia and ammonia-N group, hypoxia group, ammonia-N group, and control group. The results demonstrated that ammonia-N and hypoxia exposures induced the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities increased first and then decreased, and malondialdehyde (MDA) accumulated. Additionally, antioxidant genes (SOD, CAT, GSH-Px, HSP70, and HSP90), apoptosis genes (p53, bax, caspase 3, caspase 8, and caspase 9), and inflammatory genes (TNF-α, IL-1β, IL-6, and IL-8) were upregulated by hypoxia and ammonia-N exposure. Severe inflammatory features were noticed in fish under hypoxia and ammonia-N co-exposure and speculating that the p53-bax pathway may induce apoptosis in hybrid groupers. Furthermore, hybrid grouper exposed to hypoxia or ammonia-N revealed some abnormalities in liver histology, with combined exposure resulting in the most severe liver tissue lesions. In summary, the hypoxia and ammonia-N co-exposure induced oxidative stress, accelerating the cell damage and activated inflammation and apoptosis.

Exogenous heat shock proteins HSPA1A and HSPB1 regulate TNF-α, IL-1β and IL-10 secretion from monocytic cells

Endogenous molecules, such as heat shock proteins (HSP), can function as danger signals when released into the extracellular environment in response to cell stress, where they elicit an immune response such as cytokine secretion. There has also been some suggestion that contamination of exogenous HSPs with lipopolysaccharide (LPS) may be responsible for these effects. This study investigates the effects of exogenous HSPA1A and HSPB1 on the activation of immune cells and the resulting secretion of cytokines, which are involved in inflammatory responses. To address whether exogenous HSPs can directly activate cytokine secretion, naïve U937 cells, differentiated U937 cells and peripheral blood mononuclear cells (PBMCs) were treated with either exogenously applied HSPA1A or HSPB1 and then secreted IL-1β, TNF-α and IL-10 were measured by ELISA. Both HSPs were able to induce a dose-dependent increase in IL-10 secretion from naïve U937 cells and dose-dependent IL-1β, TNF-α and IL-10 secretion were also observed in differentiated U937 cells and PBMCs. We also observed that CD14 affects the secretion levels of IL-1β, TNF-α and IL-10 from cells in response to exogenous HSP treatment. In addition, HSPA1A and HSPB1 were shown to interact with CD14, CD36 and CD11b extracellular receptor proteins. Several approaches used in this study indicate that HSP-induced cytokine secretion is largely independent of any contaminating LPS in the samples.

Heat shock proteins in cancer - Known but always being rediscovered: Their perspectives in cancer immunotherapy

Heat shock proteins (HSPs) represent cellular chaperones that are classified into several families, including HSP27, HSP40, HSP60, HSP70, and HSP90. The role of HSPs in the cell includes the facilitation of protein folding and maintaining protein structure. Both processes play crucial roles during stress conditions in the cell such as heat shock, degradation, and hypoxia. Moreover, HSPs are important modulators of cellular proliferation and differentiation, and are strongly associated with the molecular orchestration of carcinogenesis. The expression and/or activity of HSPs in cancer cells is generally abnormally high and is associated with increased metastatic potential and activity of cancer stem cells, more pronounced angiogenesis, downregulated apoptosis, and the resistance to anticancer therapy in many patients. Based on the mentioned reasons, HSPs have strong potential as valid diagnostic, prognostic, and therapeutic biomarkers in clinical oncology. In addition, numerous papers describe the role of HSPs as chaperones in the regulation of immune responses inside and outside the cell. Importantly, highly expressed/activated HSPs may be inhibited via immunotherapeutic targets in various types of cancers. The aim of this work is to provide a comprehensive overview of the relationship between HSPs and the tumor cell with the intention of highlighting the potential use of HSPs in personalized cancer management.

Atheroprotective Aspects of Heat Shock Proteins

Atherosclerosis is a major global health problem. Being a harbinger of a large number of cardiovascular diseases, it ultimately leads to morbidity and mortality. At the same time, effective measures for the prevention and treatment of atherosclerosis have not been developed, to date. All available therapeutic options have a number of limitations. To understand the mechanisms behind the triggering and development of atherosclerosis, a deeper understanding of molecular interactions is needed. Heat shock proteins are important for the normal functioning of cells, actively helping cells adapt to gradual changes in the environment and survive in deadly conditions. Moreover, multiple HSP families play various roles in the progression of cardiovascular disorders. Some heat shock proteins have been shown to have antiatherosclerotic effects, while the role of others remains unclear. In this review, we considered certain aspects of the antiatherosclerotic activity of a number of heat shock proteins.

Effects of ammonia exposure on anxiety behavior, oxidative stress and inflammation in guppy (Poecilia reticulate)

Ammonia is one of the most important aquatic environmental factors, which is of great concern. In order to evaluate the effect of ammonia on guppy (Poecilia reticulate), fish were exposed to increased concentrations (0, 12.50, 25.00, 41.67, 62.50 mg/L) of ammonia for 48 h. After exposure, we measured the anxiety behavior, antioxidant enzymes and pro-inflammation genes (TNF-α, IL-1β and IL-6) of guppy. The results showed that ammonia stress induced fish anxiety, which was manifested by the increased latency to enter the upper half and decreased time spent in upper half compared with control fish. The guppy showed oxidative stress after 48 h of ammonia stress as evidenced by decreases in the activities of antioxidant enzymes and an increase in lipid hydroperoxide content. With prolonged ammonia stress, the expressions of HSP70, HSP90, TNF-α, IL-1β and IL-6 mRNA at first had an increasing trend, and then decreased, all of which were significantly higher than the control levels at 12 h and 24 h after ammonia stress (P < 0.05). Ammonia significantly upregulated these genes mRNA levels after 48 h exposure, suggesting that heat shock proteins and innate immune system may try to protect cells from oxidative stress induced by ammonia stress. Our study showed that higher ammonia exposure induced oxidative stress in exposed fish, since inhibition of antioxidant enzymes activity and increases in lipid peroxidation, and inflammation occurred. Furthermore, the results will be helpful to understand the mechanism of ammonia toxicity in guppys.

Protein expression changes during phagocytosis influenced by low-frequency electromagnetic field exposure

The aim of our studies was to determine the influence of a low-frequency electromagnetic field (EMF) on the phagocytosis of latex beads (LBs) and the expression level of proteins/genes in the human monocytic macrophage Mono Mac 6 (MM6) cell line in in vitro conditions. Before phagocytosis assay cells were pre-stimulated with infectious agents such as lipopolysaccharide (LPS), Staphylococcal enterotoxin B (SEB), or the proliferatory agent phytohaemagglutinin (PHA), and then exposed to EMF (30 mT, 7 Hz, 3 h). The expression of cytoplasmic proteins like iPLA, cPLA, iNOS, NLR3/4, and Hsp70 involved in the immune response pathways to phagocytosed particles were evaluated with the usage of the Western blot analysis. mRNA encoding the iNOS protein was detected by reverse transcription PCR method. The most meaningful changes were observed for PLA2 and NLC4 proteins level and between iNOS protein expression and mRNA encoding iNOS protein amount. The EMF exposure exerted the strongest effect on iNOS encoding mRNA in cells pre-stimulated with LPS or SEB and phagocytosing LBs. The influence of EMF on phagocytosis was experimentally proved for the first time and there is a need for further investigations in term of the usage of EMF as a prospect, supportive therapy.

Laser ablation: Heating up the anti-tumor response in the intracranial compartment

Immunotherapies, such as immune checkpoint inhibition (ICI), have had limited success in treating intracranial malignancies. These failures are due partly to the restrictive blood-brain-barrier (BBB), the profound tumor-dependent induction of local and systemic immunosuppression, and immune evasion exhibited by these tumors. Therefore, novel approaches must be explored that aim to overcome these stringent barriers. LITT is an emerging treatment for brain tumors that utilizes thermal ablation to kill tumor cells. LITT provides an additional therapeutic benefit by synergizing with ICI and systemic chemotherapies to strengthen the anti-tumor immune response. This synergistic relationship involves transient disruption of the BBB and local augmentation of immune function, culminating in increased CNS drug penetrance and improved anti-tumor immunity. In this review, we will provide an overview of the challenges facing immunotherapy for brain tumors, and discuss how LITT may synergize with the endogenous anti-tumor response to improve the efficacy of ICI.

NTPDase8 protects mice from intestinal inflammation by limiting P2Y6 receptor activation: identification of a new pathway of inflammation for the potential treatment of IBD

OBJECTIVE

Nucleotides are danger signals that activate inflammatory responses via binding P2 receptors. The nucleoside triphosphate diphosphohydrolase-8 (NTPDase8) is an ectonucleotidase that hydrolyses P2 receptor ligands. We investigated the role of NTPDase8 in intestinal inflammation.

DESIGN

We generated NTPDase8-deficient (Entpd8-/-) mice to define the role of NTPDase8 in the dextran sodium sulfate (DSS) colitis model. To assess inflammation, colons were collected and analysed by histopathology, reverse transcriptase-quantitative real-time PCR (RT-qPCR) and immunohistochemistry. P2 receptor expression was analysed by RT-qPCR on primary intestinal epithelium and NTPDase8 activity by histochemistry. The role of intestinal P2Y6 receptors was assessed by bone marrow transplantation experiments and with a P2Y6 receptor antagonist.

RESULTS

NTPDase8 is the dominant enzyme responsible for the hydrolysis of nucleotides in the lumen of the colon. Compared with wild-type (WT) control mice, the colon of Entpd8-/- mice treated with DSS displayed significantly more histological damage, immune cell infiltration, apoptosis and increased expression of several proinflammatory cytokines. P2Y6 was the dominant P2Y receptor expressed at the mRNA level by the colonic epithelia. Irradiated P2ry6-/- mice transplanted with WT bone marrow were fully protected from DSS-induced intestinal inflammation. In agreement, the daily intrarectal injection of a P2Y6 antagonist protected mice from DSS-induced intestinal inflammation in a dose-dependent manner. Finally, human intestinal epithelial cells express NTPDase8 and P2Y6 similarly as in mice.

CONCLUSION

NTPDase8 protects the intestine from inflammation most probably by limiting the activation of P2Y6 receptors in colonic epithelial cells. This may provide a novel therapeutic strategy for the treatment of inflammatory bowel disease.

Immunological responses and anti-tumor effects of HPV16/18 L1-L2-E7 multiepitope fusion construct along with curcumin and nanocurcumin in C57BL/6 mouse model

AIMS

Human papillomavirus (HPV) L1, L2 and E7 proteins were used as target antigens for development of preventive and therapeutic vaccines. Moreover, linkage of antigens to heat shock proteins (HSPs) could enhance the potency of vaccines. Curcumin and nanocurcumin compounds were suggested as the chemopreventive and chemotherapeutic agents against cancer. In this study, two multiepitope DNA and peptide-based vaccine constructs (L1-L2-E7 and HSP70-L1-L2-E7) were used along with curcumin and nanocurcumin to evaluate immune responses, and protective/therapeutic effects in tumor mouse model.

MAIN METHODS

At first, the multiepitope L1-L2-E7 and HSP70-L1-L2-E7 fusion genes were subcloned in eukaryotic and prokaryotic expression vectors. The recombinant multiepitope peptides were generated in E. coli strain. Then, the cytotoxic effects of curcumin and nanocurcumin were evaluated on HEK-293 T non-cancerous and C3 cancerous cells. Finally, mice vaccination was performed using different regimens. Curcumin and nanocurcumin compounds were administered alone or along with different vaccine constructs.

KEY FINDINGS

Our data indicated that the use of nanocurcumin along with the multiepitope HSP70-L1-L2-E7 vaccine construct could completely protect mice against HPV-related C3 tumor cells, and eradicate tumors in a therapeutic test. Furthermore, nanocurcumin showed higher protection than curcumin alone. Generally, curcumin and nanocurcumin compounds could reduce tumor growth synergistically with the multiepitope vaccine constructs, but they did not influence the immune responses in different regimens.

SIGNIFICANCE

These data demonstrated that the designed multiepitope vaccine constructs along with curcumin and nanocurcumin can be used as a promising method for HPV vaccine development.

Extracellular vesicles and immunogenic stress in cancer

Tumor progression requires bidirectional cell-to-cell communication within a complex tumor microenvironment (TME). Extracellular vesicles (EVs) as carriers have the capacity to shuttle regulatory molecules, including nucleic acids, proteins, and lipids, between cancer cells and multiple stromal cells, inducing remarkable phenotypic alterations in the TME. Recently proposed the concept “immunogenic stress”, which means in some stressed microenvironment, cancer cells can release EVs containing specific immunoregulatory mediators, depending on the initiating stress-associated pathway, thereby provoking the changes of immune status in the TME. Considerable evidence has revealed that the intracellular mechanisms underlying the response to diverse stresses are mainly autophagy, endoplasmic reticulum (ER) stress reactions and the DNA damage response (DDR). In addition, the activation of immunogenic stress responses endows hosts with immune surveillance capacity; in contrast, several cargoes in EVs under immunogenic stress trigger a passive immune response by mediating the function of immune cells. This review discusses the current understanding of the immunogenic stress pathways in cancer and describes the interrelation between EVs and immunogenic stress to propose potential treatment strategies and biomarkers.

High concentrations of environmental ammonia induced changes in large-scale loach (Paramisgurnus dabryanus) immunity

High concentrations of environmental ammonia can cause reduced immunity and death in fish, causing enormous economic losses. Air-breathing fish usually have a high ammonia tolerance and are very suitable for high-density fish farming. However, research on the effects of environmental ammonia on air-breathing fish immunity is lacking. Therefore, this study investigated the effects of environmental ammonia on the immunity of large-scale loach (Paramisgurnus dabryanus) by exposing fish to 30 mmol/L NH4Cl solution and subsequently analyzing the changes in serum and liver immune indicators, including total protein, albumin, globulin, immunoglobulin (Ig) M, lysozyme, complement component (C) 3 and C4, heat shock protein (HSP) 70, HSP90, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-12. Results revealed that ammonia exposure significantly affected the total protein, albumin, globulin, IgM, complement C3 and C4, HSP70, HSP90, and inflammatory cytokine contents in the body, indicating that ammonia exposure induced a significant immune response and lowered bodily immunity. However, most of the immune indicators significantly decreased in the later stages of the experiment, suggesting a weakened immune response, which may be due to the species-specific ammonia detoxification ability of large-scale loach that reduces ammonia toxicity in the body.

Tumor necrosis: A synergistic consequence of metabolic stress and inflammation

Tumor necrosis is a common histological feature and poor prognostic predictor in various cancers. Despite its significant clinical implications, the mechanism underlying tumor necrosis remains largely unclear due to lack of appropriate pre-clinical modeling. We propose that tumor necrosis is a synergistic consequence of metabolic stress and inflammation, which lead to oxidative stress-induced cell death, such as ferroptosis. As a natural consequence of tumor expansion, tumor cells are inevitably stripped of vascular supply, resulting in deprivation of oxygen and nutrients. The resulting metabolic stress has commonly been considered the cause of tumor necrosis. Recent studies found that immune cells, such as neutrophils, when recruited to tumors, can directly trigger ferroptosis in tumor cells, suggesting that immune cells can be involved in amplifying tumor necrosis. This article will discuss potential mechanisms underlying tumor necrosis development and its impact on tumor progression as well as the immune response to tumors.

Broadly Protective CD8+ T Cell Immunity to Highly Conserved Epitopes Elicited by Heat Shock Protein gp96-Adjuvanted Influenza Monovalent Split Vaccine

Currently, immunization with inactivated influenza virus vaccines is the most prevalent method to prevent infections. However, licensed influenza vaccines provide only strain-specific protection and need to be updated and administered yearly; thus, new vaccines that provide broad protection against multiple influenza virus subtypes are required. In this study, we demonstrated that intradermal immunization with gp96-adjuvanted seasonal influenza monovalent H1N1 split vaccine could induce cross-protection against both group 1 and group 2 influenza A viruses in BALB/c mouse models. Vaccination in the presence of gp96 induced an apparently stronger antigen-specific T cell response than split vaccine alone. Immunization with the gp96-adjuvanted vaccine also elicited an apparent cross-reactive CD8⁺ T cell response that targeted the conserved epitopes across different influenza virus strains. These cross-reactive CD8⁺ T cells might be recalled from a pool of memory cells established after vaccination and recruited from extrapulmonary sites to facilitate viral clearance. Of note, six highly conserved CD8⁺ T epitopes from the viral structural proteins hemagglutinin (HA), M1, nucleoprotein (NP), and PB1 were identified to play a synergistic role in gp96-mediated cross-protection. Comparative analysis showed that most of conservative epitope-specific cytotoxic T lymphocytes (CTLs) apparently induced by heterologous virus infection were also activated by gp96-adjuvanted vaccine, thus resulting in broader protective CD8⁺ T cell responses. Our results demonstrated the advantage of adding gp96 to an existing seasonal influenza vaccine to improve its ability to provide better cross-protection.IMPORTANCE Owing to continuous mutations in hemagglutinin (HA) or neuraminidase (NA) or recombination of the gene segments between different strains, influenza viruses can escape the immune responses developed by vaccination. Thus, new strategies aimed to efficiently activate immune response that targets to conserved regions among different influenza viruses are urgently needed in designing broad-spectrum influenza vaccine. Heat shock protein gp96 is currently the only natural T cell adjuvant with special ability to cross-present coupled antigen to major histocompatibility complex class I (MHC-I) molecule and activate the downstream antigen-specific CTL response. In this study, we demonstrated the advantages of adding gp96 to monovalent split influenza virus vaccine to improve its ability to provide cross-protection in the BALB/c mouse model and proved that a gp96-activated cross-reactive CTL response is indispensable in our vaccine strategy. Due to its unique adjuvant properties, gp96 might be a promising adjuvant for designing new broad-spectrum influenza vaccines.

Multi-epitope DnaK peptide vaccine accords protection against lethal S. typhimurium challenge: Elicits both cell mediated immunity and long-lasting serum-neutralizing antibody titers

Typhoid vaccine development has been impeded by inability of currently available vaccines to induce cellular immunity along with neutralizing antibodies against all serovars of S. Typhi and S. Paratyphi. Unfortunately, antibiotic treatment has shown to be an ineffective therapy due to development of resistance against multiple antibiotics. In the present study, we have explored the immunogenicity and protective efficacy of in-silico designed multi-epitope DnaK peptides as candidate vaccine molecules against Salmonella. Immunization studies in mouse typhoid model revealed three of these peptides (DP1, DP5 and DP7) are highly efficacious, stimulating both humoral and cell mediated immunity along with long lasting antibody memory response. There was significant increase in antibody titers (IgG, IgG1, IgG2a, IgA and IgM), lymphocyte proliferative responses and cytokine levels. Immunized groups showed marked reduction in organ bacterial load, fecal shedding and pronounced protection (upto 80%) as compared to unimmunized controls after challenge with S. typhimurium. Our results demonstrate the huge potential of DnaK peptide vaccine candidates (DP1, DP5 and DP7) to accord protective immunity with significant increase in survivability against Salmonella infection in mice, thus commending these molecules as promising agents to tackle typhoid.

Immunotherapy and radiation for high-grade glioma: a narrative review

Glioblastoma and other high-grade gliomas (HGGs) are the most common and deadly primary brain tumors. Due to recent advances in immunotherapy and improved clinical outcomes in other disease sites, the study of immunotherapy in HGG has increased significantly. Herein, we summarize and evaluate existing evidence and ongoing clinical trials investigating the use of immunotherapy in the treatment of HGG, including therapeutic vaccination, immune checkpoint inhibition, adoptive lymphocyte transfer, and combinatorial approaches utilizing radiation and multiple modalities of immunotherapy. Special attention is given to the mechanisms by which radiation may improve immunogenicity in HGG, why this motivates the study of radiation in combination with immunotherapy, and how to determine optimal dosing and scheduling of radiation. Though larger randomized controlled trials have not consistently shown improvements in clinical outcomes, this area of research is still in its early stages and a number of important lessons can be taken away from the studies that have been completed to date. Many studies found a subset of patients who experienced durable responses, and analysis of their immune cells and tumor cells can be used to identify biomarkers that predict therapeutic response, as well as additional glioma-specific targets that can enhance therapeutic efficacy in a challenging tumor type.

Heat Shock Proteins 90 kDa: Immunomodulators and Adjuvants in Vaccine Design Against Infectious Diseases

Heat shock proteins 90 kDa (Hsp90s) were originally identified as stress-responsive proteins and described to participate in several homeostatic processes. Additionally, extracellular Hsp90s have the ability to bind to surface receptors and activate cellular functions related to immune response (cytokine secretion, cell maturation, and antigen presentation), making them very attractive to be studied as immunomodulators. In this context, Hsp90s are proposed as new adjuvants in the design of novel vaccine formulations that require the induction of a cell-mediated immune response to prevent infectious diseases. In this review, we summarized the adjuvant properties of Hsp90s when they are either alone, complexed, or fused to a peptide to add light to the knowledge of Hsp90s as carriers and adjuvants in the design of vaccines against infectious diseases. Besides, we also discuss the mechanisms by which Hsp90s activate and modulate professional antigen-presenting cells.

Perinatal Infection: A Major Contributor to Efficacy of Cooling in Newborns Following Birth Asphyxia

Neonatal encephalopathy (NE) is a global burden, as more than 90% of NE occurs in low- and middle-income countries (LMICs). Perinatal infection seems to limit the neuroprotective efficacy of therapeutic hypothermia. Efforts made to use therapeutic hypothermia in LMICs treating NE has led to increased neonatal mortality rates. The heat shock and cold shock protein responses are essential for survival against a wide range of stressors during which organisms raise their core body temperature and temporarily subject themselves to thermal and cold stress in the face of infection. The characteristic increase and decrease in core body temperature activates and utilizes elements of the heat shock and cold shock response pathways to modify cytokine and chemokine gene expression, cellular signaling, and immune cell mobilization to sites of inflammation, infection, and injury. Hypothermia stimulates microglia to secret cold-inducible RNA-binding protein (CIRP), which triggers NF-κB, controlling multiple inflammatory pathways, including nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasomes and cyclooxygenase-2 (COX-2) signaling. Brain responses through changes in heat shock protein and cold shock protein transcription and gene-expression following fever range and hyperthermia may be new promising potential therapeutic targets.

Hsp70 in cancer: A double agent in the battle between survival and death

The heat shock protein (Hsps) superfamily, also known as molecular chaperones, are highly conserved and present in all living organisms and play vital roles in protein fate. The HspA1A (Hsp70-1), called Hsp70 in this review, is expressed at low or undetectable levels in most unstressed normal cells, but numerous studies have shown that diverse types of tumor cells express Hsp70 at the plasma membrane that leads to resistance to programmed cell death and tumor progression. Hsp70 is released into the extracellular milieu in three forms including free soluble, complexed with cancer antigenic peptides, and exosome forms. Therefore, it seems to be a promising therapeutic target in human malignancies. However, a great number of studies have indicated that both intracellular and extracellular Hsp70 have a dual function. A line of evidence presented that intracellular Hsp70 has a cytoprotective function via suppression of apoptosis and lysosomal cell death (LCD) as well as that extracellular Hsp70 can promote tumorigenesis and angiogenesis. Other evidence showed intracellular Hsp70 can promote apoptosis and membrane-associated/extracellular Hsp70 can elicit antitumor innate and adaptive immune responses. Given the contradictory functions, as a "double agent," could Hsp70 be a promising tool in the future of targeted cancer therapies? To answer this question, in this review, we will discuss the functions of Hsp70 in cancers besides inhibition and stimulation strategies for targeting Hsp70 along with their challenges.

TLR-4 Signaling vs. Immune Checkpoints, miRNAs Molecules, Cancer Stem Cells, and Wingless-Signaling Interplay in Glioblastoma Multiforme-Future Perspectives

Toll-like-receptor (TLR) family members were detected in the central nervous system (CNS). TLR occurrence was noticed and widely described in glioblastomamultiforme (GBM) cells. After ligand attachment, TLR-4 reorients domains and dimerizes, activates an intracellular cascade, and promotes further cytoplasmatic signaling. There is evidence pointing at a strong relation between TLR-4 signaling and micro ribonucleic acid (miRNA) expression. The TLR-4/miRNA interplay changes typical signaling and encourages them to be a target for modern immunotherapy. TLR-4 agonists initiate signaling and promote programmed death ligand-1 (PD-1L) expression. Most of those molecules are intensively expressed in the GBM microenvironment, resulting in the autocrine induction of regional immunosuppression. Another potential target for immunotreatment is connected with limited TLR-4 signaling that promotes Wnt/DKK-3/claudine-5 signaling, resulting in a limitation of GBM invasiveness. Interestingly, TLR-4 expression results in bordering proliferative trends in cancer stem cells (CSC) and GBM. All of these potential targets could bring new hope for patients suffering from this incurable disease. Clinical trials concerning TLR-4 signaling inhibition/promotion in many cancers are recruiting patients. There is still a lot to do in the field of GBM immunotherapy.

Exosomes released by breast cancer cells under mild hyperthermic stress possess immunogenic potential and modulate polarization in vitro in macrophages

Macrophages play a dual role in tumor initiation and progression, with both tumor-promoting and tumor-suppressive effects; hence, it is essential to understand the distinct responses of macrophages to tumor progression and therapy. Mild hyperthermia has gained importance as a therapeutic regimen against cancer due to its immunogenic nature, efficacy, and potential synergy with other therapies, yet the response of macrophages to molecular signals from hyperthermic cancer cells has not yet been clearly defined. Due to limited response rate of breast cancer to conventional therapeutics the development, and understanding of alternative therapies like hyperthermia is pertinent. In order to determine conditions corresponding to mild thermal dose, cytotoxicity of different hyperthermic temperatures and treatment durations were tested in normal murine macrophages and breast cancer cell lines. Examination of exosome release in hyperthermia-treated cancer cells revealed enhanced efflux and a larger size of exosomes released under hyperthermic stress. Exposure of naïve murine macrophages to exosomes released from 4T1 and EMT-6 cells posthyperthermia treatment, led to an increased expression of specific macrophage activation markers. Further, exosomes released by hyperthermia-treated cancer cells had increased content of heat shock protein 70 (Hsp70). Together, these results suggest a potential immunogenic role for exosomes released from cancer cells treated with mild hyperthermia.

Heat Shock Proteins in Cancer Immunotherapy

Heat shock proteins (HSPs) are highly conserved molecular chaperones with divergent roles in various cellular processes. The HSPs are classified according to their molecular size as HSP27, HSP40, HSP60, HSP70, and HSP90. The HSPs prevent nonspecific cellular aggregation of proteins by maintaining their native folding energetics. The disruption of this vital cellular process, driven by the aberrant expression of HSPs, is implicated in the progression of several different carcinomas. Many HSPs are also actively involved in promoting the proliferation and differentiation of tumor cells, contributing to their metastatic phenotype. Upregulation of these HSPs is associated with the poor outcome of anticancer therapy in clinical settings. On the other hand, these highly expressed HSPs may be exploited as viable immunotherapeutic targets for different types of cancers. This review discusses recent advances and perspectives on the research of HSP-based cancer immunotherapy.

Heat Shock Proteins in Glioblastoma Biology: Where Do We Stand?

Heat shock proteins (HSPs) are evolutionary conserved proteins that work as molecular chaperones and perform broad and crucial roles in proteostasis, an important process to preserve the integrity of proteins in different cell types, in health and disease. Their function in cancer is an important aspect to be considered for a better understanding of disease development and progression. Glioblastoma (GBM) is the most frequent and lethal brain cancer, with no effective therapies. In recent years, HSPs have been considered as possible targets for GBM therapy due their importance in different mechanisms that govern GBM malignance. In this review, we address current evidence on the role of several HSPs in the biology of GBMs, and how these molecules have been considered in different treatments in the context of this disease, including their activities in glioblastoma stem-like cells (GSCs), a small subpopulation able to drive GBM growth. Additionally, we highlight recent works that approach other classes of chaperones, such as histone and mitochondrial chaperones, as important molecules for GBM aggressiveness. Herein, we provide new insights into how HSPs and their partners play pivotal roles in GBM biology and may open new therapeutic avenues for GBM based on proteostasis machinery.

Staphylococcus aureus Exploits the Host Apoptotic Pathway To Persist during Infection

Staphylococcus aureus is a deadly pathogen that causes fatal diseases in humans. During infection, S. aureus secretes nuclease (Nuc) and adenosine synthase A (AdsA) to generate cytotoxic deoxyadenosine (dAdo) from neutrophil extracellular traps which triggers noninflammatory apoptosis in macrophages. In this manner, replicating staphylococci escape phagocytic killing without alerting the immune system. Here, we show that mice lacking caspase-3 in immune cells exhibit increased resistance toward S. aureus Caspase-3-deficient macrophages are resistant to staphylococcal dAdo and gain access to abscess lesions to promote bacterial clearance in infected animals. We identify specific single nucleotide polymorphisms in CASP3 as candidate human resistance alleles that protect macrophages from S. aureus-derived dAdo, raising the possibility that the allelic repertoire of caspase-3 may contribute to the outcome of S. aureus infections in humans.IMPORTANCE Caspase-3 controls the apoptotic pathway, a form of programmed cell death designed to be immunologically silent. Polymorphisms leading to reduced caspase-3 activity are associated with variable effects on tumorigenesis and yet arise frequently. Staphylococcus aureus is a human commensal and a frequent cause of soft tissue and bloodstream infections. Successful commensalism and virulence can be explained by the secretion of a plethora of immune evasion factors. One such factor, AdsA, destroys phagocytic cells by exploiting the apoptotic pathway. However, human CASP3 variants with loss-of-function alleles shield phagocytes from AdsA-mediated killing. This finding raises the possibility that some caspase-3 alleles may arise from exposure to S. aureus and other human pathogens that exploit the apoptotic pathway for infection.

Immunological considerations underlying heat shock protein-mediated cancer vaccine strategies

The success of active immunotherapies in the prevention of many infectious diseases over the course of over 200 years has lead scientists to wonder if the same principles could be applied to cancer. Antigen-specific active immunotherapies for the treatment of cancer have been researched for over two decades, however, the overwhelming majority of these studies have failed to stimulate robust clinical responses. It is clear that current active immunotherapy research should incorporate methods to increase the immunostimulatory capacity of these therapies. To directly address this need, we propose the addition of the immunostimulatory heat shock proteins (HSPs) to active immunotherapeutic strategies to augment their efficacy. Heat shock proteins are a family of highly conserved intracellular chaperone proteins, and are the most abundant family proteins inside cells. This ubiquity, and their robust immunostimulatory capacity, points to their importance in regulation of intracellular processes and, therefore, indicators of loss of cellular integrity if found extracellularly. Thus, we emphasize the importance of taking into consideration the location of vaccine-derived HSP/tumor-antigen complexes when designing active immunotheraputic strategies.

Tumor Vaccines for Malignant Gliomas

Despite continued research efforts, glioblastoma multiforme (GBM) remains the deadliest brain tumor. Immunotherapy offers a novel way to treat this disease, the genetic signature of which is not completely elucidated. Additionally, these tumors are known to induce immunosuppression in the surrounding tumor microenvironment via an array of mechanisms, making effective treatment all the more difficult. The immunotherapeutic strategy of using tumor vaccines offers a way to harness the activity of the host immune system to potentially control tumor progression. GBM vaccines can react to a variety of tumor-specific antigens, which can be harvested from the patient's unique pathological condition using selected immunotherapy techniques. This article reviews the rationale behind and development of GBM vaccines, the relevant clinical trials, and the challenges involved in this treatment strategy.

B-Cell-Based and Soluble Biomarkers in Body Liquids for Predicting Acute/Chronic Graft-versus-Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the main curative therapy for hematological malignancy such as leukemias, lymphomas, or multiple myelomas and some other hematological disorders. In this therapy, cure of hematological diseases relies on graft-versus-malignancy effects by allogenic immune cells. However, severe posttransplant treatment-associated complications such as acute graft-versus-host disease (aGvHD) and chronic graft-versus-host disease (cGvHD) limit this approach. Most research into GvHD has concentrated on the aGvHD, while the more complex and multifaceted chronic form has been largely poorly investigated. cGvHD is a multi-organ autoimmune disorder and is the major cause of non-relapse morbidity and mortality following allo-HSCT, occurring in about 50% of patients, or 13,000–15,000 patients per year worldwide. Therefore, there is a high medical need for an early prediction of these therapy-associated toxicities. Biomarkers have gained importance over the last decade in diagnosis, in prognosis, and in prediction of pending diseases or side effects. Biomarkers can be cells, factors isolated from target tissues, or soluble factors that can be detected in body fluids. In this review, we aim to summarize some of the recent developments of biomarkers in the field of allo-HSCT. We will focus on cell-based biomarkers (B-cell subsets) for cGvHD and soluble factors including microRNA (miRNA), which are excreted into serum/plasma and urine. We also discuss the potential role of cytosolic and extracellular 70 kDa heat shock proteins (HSP70) as potential biomarkers for aGvHD and their role in preclinical models. Proteomic biomarkers in the blood have been used as predictors of treatment responses in patients with aGvHD for many years. More recently, miRNAs have been found to serve as a biomarker to diagnose aGvHD in the plasma. Another development relates to urine-based biomarkers that are usually detected by capillary electrophoresis and mass spectrometry. These biomarkers have the potential to predict the development of severe aGvHD (grades III–IV), overall mortality, and the pending development of cGvHD in patients posttransplant.

Role of nitric oxide in liver transplantation: Should it be routinely used?

Ischemia-reperfusion injury (IRI) continues to be a major contributor to graft dysfunction, thus supporting the need for therapeutic strategies focused on minimizing organ damage especially with growing numbers of extended criteria grafts being utilized which are more vulnerable to cold and warm ischemia. Nitric oxide (NO·) is highly reactive gaseous molecule found in air and regarded as a pollutant. Not surprising, it is extremely bioactive, and has been demonstrated to play major roles in vascular homeostasis, neurotransmission, and host defense inflammatory reactions. Under conditions of ischemia, NO· has consistently been demonstrated to enhance microcirculatory vasorelaxation and mitigate pro-inflammatory responses, making it an excellent strategy for patients undergoing organ transplantation. Clinical studies designed to test this hypothesis have yielded very promising results that includes reduced hepatocellular injury and enhanced graft recovery without any identifiable complications. By what means NO· facilitates extra-pulmonary actions is up for debate and speculation. The general premise is that they are NO· containing intermediates in the circulation, that ultimately mediate either direct or indirect effects. A plethora of data exists explaining how NO·-containing intermediate molecules form in the plasma as S-nitrosothiols (e.g., S-nitrosoalbumin), whereas other compelling data suggest nitrite to be a protective mediator. In this article, we discuss the use of inhaled NO· as a way to protect the donor liver graft against IRI in patients undergoing liver transplantation.

Review: Pathogen-associated molecular pattern contamination as putative endogenous ligands of Toll-like receptors

Extensive work in recent years has suggested that a number of endogenous molecules, their derivatives or degradation products may be potent activators of the innate immune system capable of inducing pro-inflammatory cytokine production by the monocyte—macrophage system and the activation and maturation of dendritic cells. The cytokine-like effects of these endogenous molecules are mediated via Toll-like receptor (TLR) signal transduction pathways in a manner similar to pathogen-associated molecular patterns (PAMPs). However, recent evidence suggests that the reported cytokine effects of some of these putative endogenous ligands are in fact due to contaminating PAMPs. The reasons for the failure to recognize PAMP contaminants being responsible for the putative TLR ligands of these endogenous molecules include: (i) failure to use highly purified preparations free of PAMP contamination; (ii) failure to recognize the heat sensitivity of lipopolysaccharide (LPS); and (iii) failure to consider contaminant(s) other than LPS. Strategies are proposed to avoid future designation of PAMP contamination as putative endogenous ligands of TLRs.

Dendritic cell vaccination with a toll-like receptor agonist derived from mycobacteria enhances anti-tumor immunity

Dendritic cell (DC)-based vaccines are considered useful in cancer immunotherapy, and the interaction of DC and adjuvants is important in the design of the next generation vaccines. In this study, whether DC combined with Rv2299c derived from mycobacteria could improve anti-tumor immune responses in a colon cancer mouse model was evaluated. MC38 cell lines were injected subcutaneously to establish colon-cancer-bearing mice and the following four groups were evaluated: PBS control, tumor antigen (TA) loaded-DC, Rv2299c, and a combination of TA-loaded-DC and Rv2299c. The combination treatment with TA-loaded-DC and Rv2299c exhibited greater inhibition of tumor growth compared to other groups. These effects were associated with the reduction of suppressor cells, such as myeloid-derived suppressor cells and regulatory T cells, and the induction of effector cells, such as CD4⁺ T cells and CD8⁺ T cells, in spleen, and with the activation of cytotoxic T Lymphocytes and NK cells. These results suggest that TA-loaded-DC vaccination with Rv2299c derived from mycobacteria enhanced anti-tumor immunity in a mouse colon cancer model by inhibiting the generation of immune-suppressive cells and recovering numbers of effector cells, and demonstrated superior polarization of the Th1/Th2 balance in favor of the Th1 immune response.

HSP70 Modulates the Enhanced Production of Reactive Intermediate Metabolites and a Proinflammatory Cytokine TNF-α Expression in a T Cell Lymphoma

Heat shock proteins are intracellular soluble proteins expressed consecutively in all cells. They are immunogenic proteins able to activate antigen-presenting cells by binding through the CD91 receptor and activate both CD4+ and CD8+ T-cells. Macrophage plays a pivotal role in innate immune response and secretes a number of regulatory molecules upon activation. In the present study, we investigate the activation of normal and tumor-associated macrophage to produce the effector molecules which have a role in immunomodulation, especially in the killing of the transformed or tumor cells. In vitro and in vivo treatment of NMO and TAMs (from T-Cell Lymphoma) with optimum dose 10 μg of hsp70 produce effector molecules such as nitric oxide (NO), hydrogen peroxide (H2O2) and tumor necrosis factor-α (TNF α). The results of our experiments reveal that the production of effector molecules is dose-dependent, and the result of immunoblots also confirms the increased expression of iNOS. These findings suggest that autologous hsp70 are highly immunogenic and potent activating agents for the enhanced production of effector molecules in NMO and TAMs in a T-cell lymphoma.

Heat Shock Proteins (HSP): Future Trends in Cancer Immunotherapy

Heat Shock Proteins (HSPs) are a large family of highly conserved proteins involved in assisting protein folding and unfolding in the cells. HSPs are expressed constitutively as well as inducibly and, interacting with antigen presenting cells, induce the expression of various cytokines and chemokines as well as the maturation and migration of dendritic cells, thus acting themselves as cytokines. HSP-chaperoned antigenic peptides are also generated within the tumor cells. Such chaperoned peptides are released in the extra cellular medium with an association of HSPs by cell stress, death or tumor cell lyses. HSP-peptide complexes from extra cellular medium are taken up by antigen presenting cells through CD91 receptor and are represented or cross-presented by their MHC class I molecules for specific anti-tumor immune response. In addition, HSPs expressed on the cell surface of tumor cells stimulate αβ T-cells and γδ T-cells as well as natural killer (NK) cells that are first-line defense mechanisms. In this manner, HSPs have the ability to stimulate both arms of the effecter mechanism of the immune system. These unique immunological attributes of HSPs are presently becoming the basis for tumor immunotherapy. Tumor-derived HSP-peptide complexes have been demonstrated to serve as anti-tumor vaccines. To date various approaches of vaccination using HSPs have been developed and tested clinically. These HSP-based vaccine approaches can be combined with hyperthermia and CTLA-4 blockade to enhance their anti-tumor potentiality.

Hepatic ischemia reperfusion injury: A systematic review of literature and the role of current drugs and biomarkers

Hepatic ischemia reperfusion injury (IRI) is not only a pathophysiological process involving the liver, but also a complex systemic process affecting multiple tissues and organs. Hepatic IRI can seriously impair liver function, even producing irreversible damage, which causes a cascade of multiple organ dysfunction. Many factors, including anaerobic metabolism, mitochondrial damage, oxidative stress and secretion of ROS, intracellular Ca(2+) overload, cytokines and chemokines produced by KCs and neutrophils, and NO, are involved in the regulation of hepatic IRI processes. Matrix Metalloproteinases (MMPs) can be an important mediator of early leukocyte recruitment and target in acute and chronic liver injury associated to ischemia. MMPs and neutrophil gelatinase-associated lipocalin (NGAL) could be used as markers of I-R injury severity stages. This review explores the relationship between factors and inflammatory pathways that characterize hepatic IRI, MMPs and current pharmacological approaches to this disease.

Psychoneuroimmunology: Then and Now

Psychoneuroimmunology (PNI) emerged in the neurosciences in the late 1970s to early 1980s and has extended to influence the fields of psychology, psychiatry, endocrinology, physiology, and the biomedical research community. This review documents the journey of PNI from the early 1980s to the present. Today, we recognize that the highly complex immune system interacts with an equally complex nervous system in a bidirectional manner. Evolutionarily old signals continue to play a role in these communications, as do mechanisms for protection of the host. The disparity between physical and psychological stressors is only an illusion. Host defense mechanisms respond in adaptive and meaningful ways to both. The present review will describe a new way of thinking about evolutionarily old molecules, heat shock proteins, adding to a body of evidence suggesting that activation of the acute stress response is a double-edged sword that can both benefit and derail optimal immunity.

Mitochondrial lysates induce inflammation and Alzheimer's disease-relevant changes in microglial and neuronal cells

Neuroinflammation occurs in Alzheimer's disease (AD). While AD genetic studies implicate inflammation-relevant genes and fibrillar amyloid-β protein promotes inflammation, our understanding of AD neuroinflammation nevertheless remains incomplete. In this study we hypothesized damage-associated molecular pattern (DAMP) molecules arising from mitochondria, intracellular organelles that resemble bacteria, could contribute to AD neuroinflammation. To preliminarily test this possibility, we exposed neuronal and microglial cell lines to enriched mitochondrial lysates. BV2 microglial cells treated with mitochondrial lysates showed decreased TREM2 mRNA, increased TNFα mRNA, increased MMP-8 mRNA, increased IL-8 mRNA, redistribution of NFκB to the nucleus, and increased p38 MAPK phosphorylation. SH-SY5Y neuronal cells treated with mitochondrial lysates showed increased TNFα mRNA, increased NFκB protein, decreased IκBα protein, increased AβPP mRNA, and increased AβPP protein. Enriched mitochondrial lysates from SH-SY5Y cells lacking detectable mitochondrial DNA (ρ0 cells) failed to induce any of these changes, while mtDNA obtained directly from mitochondria (but not PCR-amplified mtDNA) increased BV2 cell TNFα mRNA. These results indicate at least one mitochondrial-derived DAMP molecule, mtDNA, can induce inflammatory changes in microglial and neuronal cell lines. Our data are consistent with the hypothesis that a mitochondrial-derived DAMP molecule or molecules could contribute to AD neuroinflammation.

Characterization of calcium oxalate crystal-induced changes in the secretome of U937 human monocytes

This is the first study to characterize changes in the secretome of human monocytes induced by calcium oxalate crystals.

Synergistic effect of muramyl dipeptide with heat shock protein 70 from Mycobacterium tuberculosis on immune activation

Heat shock protein 70 from Mycobacterium tuberculosis (Mtb Hsp70) has been known to modulate immune response including dendritic cell activation. Muramyl dipeptide (MDP) is an immunoreactive derivative of peptidoglycan from all Gram-negative and Gram-positive bacteria and recognized to be responsible for function of Freund's complete adjuvant. In this study, we evaluated effect of MDP on in vitro activation of bone marrow derived dendritic cells (BMDCs) and in vivo production of cytokines and chemokines induced by Mtb Hsp70. MDP treatment with Mtb Hsp70 dramatically increased production of IL-6, IL-12p40 and TNF-α in BMDCs compared with Mtb Hsp70 alone whereas these effects were abolished in Nod2-deficient BMDCs. Phosphorylation of IκB-α and ERK and impairment of phagocytosis, which is an indicator of DC maturation were enhanced by MDP co-treatment with Mtb hsp70 in BMDCs. In addition, ability of Mtb Hsp70-stimulated BMDCs to induce IFN-γ productions of T cells was increased by MDP co-treatment. Finally, intraperitoneal injection of MDP with Mtb Hsp70 dramatically increased production of IL-6, CXCL-1 and CCL2 in serum compared with Mtb hsp70 injection. Our study showed the synergistic effects of MDP with Mtb Hsp70 on DCs and in vivo immune activation. The use of MDP with Mtb Hsp70 to induce immune activation may provide an effective strategy for vaccination to treat cancer and protect against pathogens.

Heat shock protein vaccines against glioblastoma: from bench to bedside

Current adjuvant treatment regimens available for the treatment of glioblastoma are widely ineffective and offer a dismal prognosis. Advancements in conventional treatment strategies have only yielded modest improvements in overall survival. Immunotherapy remains a promising adjuvant in the treatment of GBM through eliciting tumor specific immune responses capable of producing sustained antitumor response while minimizing systemic toxicity. Heat shock proteins (HSP) function as intracellular chaperones and have been implicated in the activation of both innate and adaptive immune systems. Vaccines formulated from HSP-peptide complexes, derived from autologous tumor, have been applied to the field of immunotherapy for glioblastoma. The results from the phase I and II clinical trials have been promising. Here we review the role of HSP in cellular function and immunity, and its application in the treatment of glioblastoma.

Hsp90, Hsp60 and sHsp families of heat shock protein genes in channel catfish and their expression after bacterial infections

Heat shock proteins (Hsps) are a suite of highly conserved proteins whose expressions are generally induced by elevated temperature. However, many Hsps play important roles in both innate and adaptive immunity. On the basis of our previous work on Hsp40 and Hsp70 gene families in channel catfish (Ictalurus punctatus), the objective of this study was to characterize Hsp90, Hsp60, Hsp10, and small Hsp genes, and to investigate their expression profiles after bacterial infections. A total of 20 Hsp genes were identified and annotated in the channel catfish genome, including five Hsp90 genes, one Hsp60 gene, one Hsp10 gene, and 13 sHsp genes. Six Hsp genes were differentially expressed after Edwardsiella ictaluri infection, and 12 were differentially expressed after Flavobacterium columnare infection. Although expression of these genes exhibited both temporal and spatial regulation, the induction of Hsp genes was observed soon after bacterial infection, while the suppression of Hsp genes was observed at later time-points, suggesting their distinct roles in immune responses and disease defenses. A pathogen-specific expression pattern of Hsp90 was observed. After F. columnare infection, all Hsp90 genes were found up-regulated except Hsp90ab1, which was not significantly regulated. However, after E. ictaluri infection, only one Hsp90 gene was found significantly down-regulated. Both pathogen-specific and tissue-specific pattern of expression were observed with small Hsps after E. ictaluri and F. columnare bacterial infections. These results suggested that most of Hsp genes may play important roles in immune response and/or disease defense in channel catfish.

Fever and the thermal regulation of immunity: the immune system feels the heat

Fever is a cardinal response to infection that has been conserved in warm-blooded and cold-blooded vertebrates for more than 600 million years of evolution. The fever response is executed by integrated physiological and neuronal circuitry and confers a survival benefit during infection. In this Review, we discuss our current understanding of how the inflammatory cues delivered by the thermal element of fever stimulate innate and adaptive immune responses. We further highlight the unexpected multiplicity of roles of the pyrogenic cytokine interleukin-6 (IL-6), both during fever induction and during the mobilization of lymphocytes to the lymphoid organs that are the staging ground for immune defence. We also discuss the emerging evidence suggesting that the adrenergic signalling pathways associated with thermogenesis shape immune cell function.

Release of endogenous heat shock protein 72 on the survival of sepsis in rats

BACKGROUND

This study was undertaken to clarify the role of extracellular heat shock protein 72 on the survival of sepsis and to determine possible factor(s) that may be responsible for it.

MATERIALS AND METHODS

Sepsis was induced by cecal ligation and puncture. Changes in serum levels of heat shock protein (Hsp72) and cytokines were determined during sepsis, and the results were correlated with the survival. Effects of heat pretreatment on Hsp72 expression in septic rat leukocytes and those of septic rat serum, lipopolysaccharide (LPS), and certain cytokines on the release of Hsp72 in macrophage NR8383 cells were determined.

RESULTS

Circulating Hsp72 levels were increased during the progress of sepsis (0, 5.5, 6.5, 10, and 6.5 ng/mL at 0, 3, 6, 9, and 18 h after cecal ligation and puncture, respectively) and the increases were correlated positively with survival rates. LPS triggered the release of Hsp72 in heat pretreated animals. Heat pretreatment increased Hsp72 expression in nonsepsis (+535%, P < 0.01) and sepsis (+116%, P<0.01%) rat leukocytes. Incubation of sepsis rat serum with NR8383 cells increased levels of extracellular heat shock protein 72 in cultured medium. Cytokine profiling revealed that among the 19 cytokines screened, four of them were increased as follows: cytokine-induced neutrophil chemoattractant 3 (+211.3%, P < 0.05), interleukin 10 (+147%, P < 0.05), MCP-1 (+49.6%, P < 0.05), and tumor necrosis factor alpha (+51.8%, P < 0.05). MCP-1 and LPS were capable of releasing Hsp72 from NR8383 cells.

CONCLUSIONS

These results demonstrate that the increases in the levels of circulating Hsp72 had a beneficial effect in improving animal survival during the progress of sepsis. The increases in circulating Hsp72 may be mediated via MCP-1 and/or LPS.

COPD and levels of Hsp70 (HSPA1A) and Hsp27 (HSPB1) in plasma and lymphocytes among coal workers: a case-control study

This case-control study aimed to investigate whether the levels of Hsp70 (HSPA1A) and Hsp27 (HSPB1) in plasma and lymphocytes were associated with the risk of chronic obstructive pulmonary disease (COPD) among coal workers. A total of 76 COPD cases and 48 age-matched healthy controls from a group of coal workers were included. The case group consisted of 35 COPD patients whose condition was complicated with coal workers' pneumoconiosis (CWP) and 41 COPD patients without CWP. Heat shock proteins (Hsps) in plasma and lymphocytes were detected by ELISA and flow cytometry, respectively. Multiple logistic regression models were applied to estimate the association between Hsp levels and COPD risk. Our results showed that plasma Hsp70 and lymphocyte Hsp27 levels were significantly higher and plasma Hsp27 levels were significantly lower in COPD cases than in controls (p < 0.01). No significant differences in lymphocyte Hsp70 levels were found between COPD cases and the matched subjects. Higher plasma Hsp70 levels (odds ratio (OR) = 13.8, 95 % confidence interval (CI) = 5.7-33.5) and lower plasma Hsp27 levels (OR = 4.6, 95 % CI = 2.0-10.5) were significantly associated with an increased risk of COPD after adjusting for confounders. Higher lymphocyte Hsp27 levels were only associated with an increased risk of COPD with CWP (OR = 6.6, 95 % CI = 2.0-22.1) but not with an increased risk of COPD without CWP (OR = 3.0, 95 % CI = 0.9-8.9). Additionally, there were strong joint effects of different Hsps on COPD risk. These results showed that higher levels of plasma Hsp70 and lower levels of plasma Hsp27 might be associated with an increased risk of COPD among coal workers. They may have the potential to serve as monitoring markers for COPD in coal workers.

Protective effects of ectoine on heat-stressed Daphnia magna

Ectoine (ECT) is an amino acid produced and accumulated by halophilic bacteria in stressful conditions in order to prevent the loss of water from the cell. There is a lack of knowledge on the effects of ECT in heat-stressed aquatic animals. The purpose of our study was to determine the influence of ECT on Daphnia magna subjected to heat stress with two temperature gradients: 1 and 0.1 °C/min in the range of 23–42 °C. Time to immobilisation, survival during recovery, swimming performance, heart rate, thoracic limb movement and the levels of heat shock protein 70 kDa 1A (HSP70 1A), catalase (CAT) and nitric oxide species (NOx) were determined in ECT-exposed and unexposed daphnids; we showed protective effects of ECT on Daphnia magna subjected to heat stress. Time to immobilisation of daphnids exposed to ECT was longer when compared to the unexposed animals. Also, survival rate during the recovery of daphnids previously treated with ECT was higher. ECT significantly attenuated a rapid increase of mean swimming velocity which was elevated in the unexposed daphnids. Moreover, we observed elevation of thoracic limb movement and modulation of heart rate in ECT-exposed animals. HSP70 1A and CAT levels were reduced in the presence of ECT. On the other hand, NOx level was slightly elevated in both ECT-treated and unexposed daphnids, however slightly higher NOx level was found in ECT-treated animals. We conclude that the exposure to ectoine has thermoprotective effects on Daphnia magna, however their mechanisms are not associated with the induction of HSP70 1A.

Secreted heat shock protein gp96-Ig: next-generation vaccines for cancer and infectious diseases

Over the past decade, our laboratory has developed a secreted heat shock protein (HSP), chaperone gp96, cell-based vaccine that generates effective anti-tumor and anti-infectious immunity in vivo. Gp96-peptide complexes were identified as an extremely efficient stimulator of MHC I-mediated antigen cross-presentation, generating CD8 cytotoxic T-lymphocyte responses detectable in blood, spleen, gut and reproductive tract to femto-molar concentrations of antigen. These studies provided the first evidence that cell-based gp96-Ig-secreting vaccines may serve as a potent modality to induce both systemic and mucosal immunity. This approach takes advantage of the combined adjuvant and antigen delivery capacity of gp96 for the generation of cytotoxic immunity against a wide range of antigens in both anti-vial and anti-cancer vaccination. Here, we review the vaccine design that utilizes the unique property/ability of endoplasmic HSP gp96 to bind antigenic peptides and deliver them to antigen-presenting cells.

Mechanisms of hepatic ischemia-reperfusion injury and protective effects of nitric oxide

Hepatic ischemia-reperfusion injury (IRI) is a pathophysiological event post liver surgery or transplantation and significantly influences the prognosis of liver function. The mechanisms of IRI remain unclear, and effective methods are lacking for the prevention and therapy of IRI. Several factors/pathways have been implicated in the hepatic IRI process, including anaerobic metabolism, mitochondria, oxidative stress, intracellular calcium overload, liver Kupffer cells and neutrophils, and cytokines and chemokines. The role of nitric oxide (NO) in protecting against liver IRI has recently been reported. NO has been found to attenuate liver IRI through various mechanisms including reducing hepatocellular apoptosis, decreasing oxidative stress and leukocyte adhesion, increasing microcirculatory flow, and enhancing mitochondrial function. The purpose of this review is to provide insights into the mechanisms of liver IRI, indicating the potential protective factors/pathways that may help to improve therapeutic regimens for controlling hepatic IRI during liver surgery, and the potential therapeutic role of NO in liver IRI.