Integrated analysis of intestinal microbiota and transcriptome reveals that a coordinated interaction of the endocrine, immune system and gut microbiota response to heat stress in Litopenaeus vannamei.

Due to the ongoing global warming, the risk of heatwaves in the oceans is continuously increasing while our understanding of the physiological response of Litopenaeus vannamei under extreme temperature conditions remains limited. Therefore, this study aimed to evaluate the physiological responses of L. vannamei under heat stress. Our results indicated that as temperature rose, the structure of intestinal and hepatopancreatic tissues was damaged sequentially. Activity of immune-related enzymes (acid phosphatase/alkaline phosphatase) initially increased before decreased, while antioxidant enzymes (superoxide dismutase and glutathione-S transferase) activity and malondialdehyde content increased with rising temperature. In addition, the total antioxidant capacity decreased with rising temperature. With the rising temperature, there was a significant increase in the expression of caspase-3, heat shock protein 70, lipopolysaccharide-induced tumor necrosis factor-α, transcriptional enhanced associate domain and yorkie in intestinal and hepatopancreatic tissues. Following heat stress, the number of potentially beneficial bacteria (Rhodobacteraceae and Gemmonbacter) increased which maintain balance and promote vitamin synthesis. Intestinal transcriptome analysis revealed 852 differentially expressed genes in the heat stress group compared with the control group. KEGG functional annotation results showed that the endocrine system was the most abundant in Organismal systems followed by the immune system. These results indicated that heat stress leads to tissue damage in shrimp, however the shrimp may respond to stress through a coordinated interaction strategy of the endocrine system, immune system and gut microbiota. This study revealed the response mechanism of L. vannamei to acute heat stress and potentially provided a theoretical foundation for future research on shrimp environmental adaptations.

Effect of chitosan on blood profile, inflammatory cytokines by activating TLR4/NF-κB signaling pathway in intestine of heat stressed mice.

Heat stress can significantly affect the immune function of the animal body. Heat stress stimulates oxidative stress in intestinal tissue and suppresses the immune responses of mice. The protecting effects of chitosan on heat stress induced colitis have not been reported. Therefore, the aim of this study was to investigate the protective effects of chitosan on immune function in heat stressed mice. Mice were exposed to heat stress (40 °C per day for 4 h) for 14 consecutive days. The mice (C57BL/6J), were randomly divided into three groups including: control group, heat stress, Chitosan group (LD: group 300 mg/kg/day, MD: 600 mg/kg/day, HD: 1000 mg/kg/day). The results showed that tissue histology was improved in chitosan groups than heat stress group. The current study showed that the mice with oral administration of chitosan groups had improved body performance as compared with the heat stress group. The results also showed that in chitosan treated groups the production of HSP70, TLR4, p65, TNF-α, and IL-10 was suppressed on day 1, 7, and 14 as compared to the heat stress group. In addition Claudin-2, and Occludin mRNA levels were upregulated in mice receiving chitosan on day 1, 7, and 14 of heat stress. Furthermore, the IL-6, IL-10, and TNF-α plasma levels were down-regulated on day 1, 7, and 14 of heat stress in mice receiving the oral administration of chitosan. In conclusion, the results showed that chitosan has an anti-inflammatory ability to tolerate hot environmental conditions.

Heat Shock Causes Lower Plasmodium Infection Rates in Anopheles albimanus.

The immune response of Anopheles mosquitoes to Plasmodium invasion has been extensively studied and shown to be mediated mainly by the nitric oxide synthase (NOS), dual oxidase (DUOX), phenoloxidase (PO), and antimicrobial peptides activity. Here, we studied the correlation between a heat shock insult, transcription of immune response genes, and subsequent susceptibility to Plasmodium berghei infection in Anopheles albimanus. We found that transcript levels of many immune genes were drastically affected by the thermal stress, either positively or negatively. Furthermore, the transcription of genes associated with modifications of nucleic acid methylation was affected, suggesting an increment in both DNA and RNA methylation. The heat shock increased PO and NOS activity in the hemolymph, as well as the transcription of several immune genes. As consequence, we observed that heat shock increased the resistance of mosquitoes to Plasmodium invasion. The data provided here could help the understanding of infection transmission under the ever more common heat waves.

Patients with Coronary Artery Disease Have Lower Levels of Antibody to Heat-Stressed Fibroblast Derived Proteins, versus Normal Subjects.

Cellular stress response plays an important role in the pathophysiology of coronary artery disease (CAD). Inhibition of cellular stress may provide a novel clinical approach regarding the diagnosis and treatment of CAD. Fibroblasts constitute 60-70% of cardiac cells and have a crucial role in cardiovascular function. Hence, the aim of this study was to show a potential therapeutic application of proteins derived from heat-stressed fibroblast in CAD patients. Fibroblasts were isolated from the foreskin and cultured under heat stress conditions. Surprisingly, 1.06% of the cells exhibited a necrotic death pattern. Furthermore, heat-stressed fibroblasts produced higher level of total proteins than control cells. In SDS-PAGE analysis, a 70 kDa protein band was observed in stressed cell culture supernatants which appeared as two acidic spots with close pI in the two-dimensional electrophoresis. To evaluate the immunogenic properties of fibroblast-derived heat shock proteins (HSPs), the serum immunoglobulin-G (IgG) was measured by ELISA in 50 CAD patients and 50 normal subjects who had been diagnosed through angiography. Interestingly, the level of anti-HSP antibody was significantly higher in non-CAD individuals in comparison with the patient's group (p < 0.05). The odds ratio for CAD was 5.06 (95%CI = 2.15-11.91) in cut-off value of 30 AU/mL of anti-HSP antibody. Moreover, ROC analysis showed that anti-HSP antibodies had a specificity of 74% and a sensitivity of 64%, which is almost equal to 66% sensitivity of exercise stress test (EST) as a CAD diagnostic method. These data revealed that fibroblast-derived HSPs are suitable for the diagnosis and management of CAD through antibody production.

Applying the silkworm model for the search of immunosuppressants.

Various stresses (high temperature, starvation, or sublethal Cryptococcal infection) increased the susceptibility of silkworms to bacterial infection by up to 100-fold, confirming the stress-induced immunosuppression reported in a range of species. When the silkworm was injected with a steroidal drug, betamethasone (1 mg/larva), the susceptibility of the silkworm to bacterial infection increased about 100-fold. This indicates that the immune function of the silkworm can be suppressed by a known compound that shows immunosuppressive effects in humans. We further tested the immunosuppressive effect of the culture supernatants (acetone extracts) of soil bacteria, and 24 out of 193 isolates showed the immunosuppressive activity. These results suggest that it is possible to search for immunosuppressive agents targeting innate immunity by using a silkworm bacterial infection model as a screening system, and that there may be candidate compounds for immunosuppressive agents among the substances produced by soil bacteria.

Dynamic changes in blood immune cell composition and function in Holstein and Jersey steers in response to heat stress.

Heat stress has detrimental effects on livestock via diverse immune and physiological changes; heat-stressed animals are rendered susceptible to diverse diseases. However, there is relatively little information available regarding the altered immune responses of domestic animals in heat stress environments, particularly in cattle steers. This study aimed to determine the changes in the immune responses of Holstein and Jersey steers under heat stress. We assessed blood immune cells and their functions in the steers of two breeds under normal and heat stress conditions and found that immune cell proportions and functions were altered in response to different environmental conditions. Heat stress notably reduced the proportions of CD21+MHCII+ B cell populations in both breeds. We also observed breed-specific differences. Under heat stress, in Holstein steers, the expression of myeloperoxidase was reduced in the polymorphonuclear cells, whereas heat stress reduced the WC1+ γδ T cell populations in Jersey steers. Breed-specific changes were also detected based on gene expression. In response to heat stress, the expression of IL-10 and IL-17A increased in Holstein steers alone, whereas that of IL-6 increased in Jersey steers. Moreover, the mRNA expression pattern of heat shock protein genes such as Hsp70 and Hsp90 was significantly increased in only Holstein steers. Collectively, these results indicate that altered blood immunological profiles may provide a potential explanation for the enhanced susceptibility of heat-stressed steers to disease. The findings of this study provide important information that will contribute to developing new strategies to alleviate the detrimental effects of heat stress on steers.

Alterations in TNF-α and its receptors expression in cows undergoing heat stress.

Heat stress is one of the environmental factors that most severely affects milk industry, as it has impact on production, immune responses and reproductive performance. The present study was conducted with high-performance Holando-Argentino cows. Our objective was to study TNF-α and its receptors pattern expression in cows from a region characterized by extreme climatic seasonality. Animals were evaluated in three periods: spring (n = 15), summer (n = 14) and autumn (n = 11). Meteorological records from a local station were used to estimate the temperature and humidity index (THI) by means of an equation previously defined. A THI higher than 68 is indicative of stressing conditions. During the summer period, the animals were exposed to 8.5 ±â€¯1.09 h of heat stress, or THI > 68. In spring, stress hours were reduced to 1.4 ±â€¯0.5 every day, while during the autumn, there were no recorded heat stress events. Expression of TNF-α, and its receptors was determined by qPCR. During the summer, TNF-α and its receptors expression diminished drastically compared to the rest of the year, when stressful conditions were infrequent. We conclude that animals that are not physiologically prepared to resist high temperatures might have a less efficient immune response, reinforcing the need to develop new strategies to improve animal welfare.

Stress and immunity in poultry: light management and nanotechnology as effective immune enhancers to fight stress.

The poultry industry plays a significant role in boosting the economy of several countries, particularly developing countries, and acts as a good, cheap, and affordable source of animal protein. A stress-free environment is the main target in poultry production. There are several stressors, such as cold stress, heat stress, high stocking density, and diseases that can affect birds and cause several deleterious changes. Stress reduces feed intake and growth, as well as impairs immune response and function, resulting in high disease susceptibility. These effects are correlated with higher corticosteroid levels that modulate several immune pathways such as cytokine-cytokine receptor interaction and Toll-like receptor signaling along with induction of excessive production of reactive oxygen species (ROS) and thus oxidative stress. Several approaches have been considered to boost bird immunity to overcome stress-associated effects. Of these, dietary supplementation of certain nutrients and management modifications, such as light management, are commonly considered. Dietary supplementations improve bird immunity by improving the development of lymphoid tissues and triggering beneficial immune modulators and responses. Since nano-minerals have higher bioavailability compared to inorganic or organic forms, they are highly recommended to be included in the bird's diet during stress. Additionally, light management is considered a cheap and safe approach to control stress. Changing light from continuous to intermittent and using monochromatic light instead of the normal light improve bird performance and health. Such changes in light management are associated with a reduction of ROS production and increased antioxidant production. In this review, we discuss the impact of stress on the immune system of birds and the transcriptome of oxidative stress and immune-related genes, in addition, how nano-minerals supplementations and light system modulate or mitigate stress-associated effects.

The involvement of PyBeclin 1 and PyLC3 in regulating the activation of autophagy in scallop Patinopecten yessoensis after acute high temperature stress.

Beclin 1 and LC3 are important autophagy regulation proteins involved in vesicle nucleation and extension stage, respectively. In the present study, a Beclin 1 and a LC3 were identified from Yesso scallop Patinopecten yessoensis (PyBeclin 1 and PyLC3). The open reading frame (ORF) of PyBeclin 1 was of 1335 bp encoding a putative polypeptide of 444 amino acid residues with an N-terminal BCL-2 homology 3 (BH3) domain, a central coiled-coil domain (CCD), and a C-terminal evolutionarily conserved domain (ECD). The ORF of PyLC3 was of 369 bp encoding a putative polypeptide of 122 amino acid residues with an APG12 domain. The deduced amino acid sequences of PyBeclin 1 and PyLC3 shared 31.92-74.09% and 68.38-79.50% identities with Beclin 1s and LC3s from other species, respectively. The mRNA transcripts of PyBeclin 1 and PyLC3 were found to be expressed in all the examined tissues, including adductor muscle, gonad, gill, haemocytes and mantle, with the highest expression level in gill and haemocytes. The mRNA expression level of PyBeclin 1 in haemocytes increased significantly at 1, 3, 6, 12 and 24 h (2.98-4.07 fold of that in the Blank group, p < 0.05), and returned to normal level at 48 h after acute high temperature stress at 25 °C. Unlike PyBeclin 1, the mRNA transcripts of PyLC3 in haemocytes were significantly up-regulated at1, 3, 6 and 12 h (1.80-2.54 fold of that in the Blank group, p < 0.05), then decreased to blank level at 24 h (p > 0.05), and increased significantly again at 48 h (3.70 fold of that in the Blank group, p < 0.05) after high temperature. PyBeclin 1 and PyLC3 were mainly located in the cytoplasm and a small amount in the nucleus with few puncta, and the numbers of PyBeclin 1 and PyLC3 puncta increased at 3 h after acute high temperature stress. The LC3-II levels in gill and haemocytes were significantly up-regulated at 1 h and 3 h after acute high temperature stress. These results collectively suggested that PyBeclin 1 and PyLC3 were conserved members of Beclin 1 and LC3 family in scallops, and involved in regulating the activation of autophagy in scallops after acute high temperature stress.

The effect of acute heat stress on the innate immune function of rainbow trout based on the transcriptome.

Heat stress is a condition in which the body's homeostasis is disturbed as a result of the rise in water temperature, resulting in the decline or even death of growth, immunity, and other functions. The mechanisms directing this response are not fully understood. To better characterize the effects of acute heat stress on the innate immune function of rainbow trout, we identified differentially regulated messenger RNA (mRNA) and non-coding RNA (ncRNA) in rainbow trout exposed to acute heat stress. Next-generation RNA sequencing and comprehensive bioinformatics analysis were conducted to characterize the transcriptome profiles, including mRNA, microRNA (miRNA), and long non-coding RNA (lncRNA). The head kidney of rainbow trout were exposed to acute heat stress at 22.5 °C for 24 h. A total of 2605 lncRNAs, 214 miRNAs, and 5608 mRNAs were identified as differentially regulated. Among these expressed genes differentially, 45 lncRNAs and 2 target genes, as well as 38 miRNAs and 14 target genes were significantly enriched in the innate immune response of rainbow trout. LncRNA is used as competitive endogenous RNA (ceRNA) to construct the ceRNA-miRNA-mRNA interaction network. Enrichment analysis of the Kyoto encyclopedia of genes and genomes (KEGG) of ceRNA, the differentially expressed genes related to the innate immune function of rainbow trout, were significantly enriched in the signaling pathway mediated by mitogen-activated protein kinase (MAPK). Overall, these analyses showed the effects of heat stress on the innate immune function in rainbow trout at the transcriptome level, providing a theoretical basis to improve the production and breeding of rainbow trout and the selection of new heat-resistant varieties.

Chronic heat stress regulates the relation between heat shock protein and immunity in broiler small intestine.

Chronic heat stress is considered to decrease the immune functions which makes negative effect on broiler growth performance. Here, we investigated the relationship between chronic heat stress, growth performance, and immunity in the small intestine of broilers. The study included two groups (control and heat stressed group) with eight replications per group. Ten broilers of 20-day aged were allocated in each replication. On day 35, the treatment group was subdivided into two groups based on their body weights (heavy and low body weight). Although, there was only the control and treatment group on day 28. The growth performance decreased and expression of heat shock protein 70 (HSP70), HSP60, and HSP47 increased on days 28 and 35 in the chronic heat stress group as compared with those in the control group. The expression levels of HSPs were significantly higher in the low body weight group than in the control group. The genes HSP70 and HSP60 were significantly associated with pro- and anti-inflammatory cytokines in the small intestine of the broilers of the treatment group. Thus, HSP70 and HSP60 activated the adaptive immunity in the small intestines of the broilers from the treatment group to allow adaptation to chronic heat stress environment.

Characterization of orange-spotted grouper (Epinephelus coioides) interferon regulatory factor 4 regulated by heat shock factor 1 during heat stress in response to antiviral immunity.

Interferon regulatory factor 4 (IRF4), in conjunction with thermogenic regulation, is a negative regulator of immune responses. Therefore, we examined whether temperature changes regulated the antiviral response of IRF4 in nervous necrosis virus (NNV)-infected orange-spotted groupers. We found that osgIRF4 mRNA expression was responsive to poly I:C stimulation and NNV infection. In vitro overexpression of osgIRF4 caused a marked decrease in the promoter activity of the antiviral protein Mx1, and magnified NNV replication. Notably, we showed that the IAD domain of osgIRF4 exerted a dominant inhibitory effect on the Mx1 promoter. Furthermore, on exposure to high temperatures, the action of osgIRF4 was dependent on heat shock factor 1 (HSF1) expression. Additionally, small interfering RNA knockdown of HSF1 abrogated high temperature-mediated osgIRF4 activity. These findings suggest that osgIRF4 is an essential negative regulator of innate antiviral immunity and enhances viral replication during heat stress in the orange-spotted grouper.

Dietary curcumin supplementation effects on blood immunological profile and liver enzymatic activity of laying hens after exposure to high temperature conditions.

Various environmental factors affect livestock production but heat stress is a major challenge in the poultry farming. Poultry exposes to high temperature alters blood immunological parameters and liver enzymatic function which in turn, suppress the immunity and disease resistance of chickens. Thus, the purpose of present study was to explore the effect of dietary curcumin supplementation on blood immunological biomarker and liver enzymatic activity of laying hens under heat stress conditions. Experimental groups contained two control groups (normal temperature control (NC) and heat stress control (HC) and 3 heat stress curcumin treatment groups (HT100, HT200 and HT300). Hens in HC group with basal diet and heat stress curcumin treatment groups were exposed 6 h/day heat stress (32 ± 1 °C) from 10:00 a.m. to 16:00 p.m. for 9 week. The results of present study showed that heat stressed curcumin treatment group had improved liver weight, WBC values and immunoglobulin level as compared to untreated HC and NC groups. The available results also indicated that laying hens supplemented with curcumin under high temperature conditions had reduced H/L ratio, serum corticosterone levels, inflammatory cytokines response and liver enzymatic activity (ALT) which enhanced the immunity of laying hens under hot climatic conditions. Therefore, it is concluded that curcumin has ability to combat harsh environmental conditions which can be used as anti-inflammatory and immune booster feed additive in the poultry nutrition.

Preventing necroptosis by scavenging ROS production alleviates heat stress-induced intestinal injury.

Background: Worldwide heat stroke incidence has increased in recent years and is associated with high morbidity and mortality. Therefore, it is critical to identify mechanisms that mediate heat stroke. Previous studies suggested that damage to the small intestine may be a major factor in heat stroke-related morbidity and mortality. However, the mechanism underlying heat stroke related small intestine injury remains unclear.Methods: To explore how heat stroke promotes intestinal damage, we applied two well established models: mouse and IEC-6 cells heat stress (HS) to mimic heat stroke both in vivo and in vitro. The percentages of viability and cell death were assessed by WST-1 and LDH release assays. Induction of HS-induced cell death was analyzed by flow cytometry with Annexin V-FITC/PI staining. Flow cytometry was used to analyze HS-induced mitochondrial superoxide with MitoSOX staining. Malondialdehyde (MDA) levels and superoxide dismutase (SOD) levels were detected by ELISA. Flow cytometry was used to analyze HS-induced mitochondrial depolarization (low ΔΨm) with JC-1 staining. Histopathology changes in the ileum were detected by H&E staining.The ileum ultrastructure was observed by transmission electron microscopy (TEM). RIPK1, RIPK3, phosphorylated MLKL, and MLKL levels were detected by Western blot. RIPK1-RIPK3 complexes were measured by immunoprecipitation assay.Results: HS increased both necrotic cell rate and RIPK1, RIPK3, and phosphorylated MLKL expression levels in IEC-6 cells. These increased expression levels promoted higher RIPK1-RIPK3 complex formation, leading to necrosome formation both in vivo and in vitro. Moreover, HS caused dyshomeostasis, an oxidative stress response, and mitochondrial damage, along with small intestinal tissue injury and cell death. However, IEC-6 cells or mice pretreated with the RIPK1 activity chemical inhibitor Nec-1 or RIPK3 activity chemical inhibitor GSK'872 significantly reversed these phenomena and promoted balance in oxidative stress response homeostasis. More importantly, the reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) pretreatment significantly inhibited HS-induced RIPK1/RIPK3-dependent necroptosis formation both in vivo and in vitro, suggesting that preventing necroptosis via scavenging ROS production might alleviate HS-induced small intestinal tissue injury and cell death.Conclusion: This study provides strong evidence that HS causes damage to both the small intestine and intestinal epithelial cells, scavenging ROS production can significantly alleviate such RIPK1/RIPK3-dependent necroptosis, mediating HS-induced intestinal damage both in vitro and in vivo. These findings provide a clear target for future mechanism-based therapeutic strategies for patients diagnosed with heat stroke.

Effects of thermal stress-induced lead (Pb) toxicity on apoptotic cell death, inflammatory response, oxidative defense, and DNA methylation in zebrafish (Danio rerio) embryos.

Lead (Pb) is a toxic environmental pollutant that is frequently present in effluents from urban, mining, and industrial sources. The combinatorial effects of heavy metal exposure and temperature in aquatic organisms have received considerable attention as heat stress occurs simultaneously in conjunction with several contaminants in a natural environment. In this study, we examined the potential effects of Pb exposure in conditions of thermal stress (34 °C) in zebrafish (Danio rerio) embryos. Thermal stress at 34 °C induced a dramatic decrease in the survival rate, although exposure to Pb at 26 °C decreased the survival rate of the embryos. Malformations, such as the curved body shape, were increased in response to exposure to a combination of Pb and heat stress. The combination of Pb and heat stress also caused a decrease in the heart rate. Moreover, Pb and high-temperature exposure induced the upregulation of SOD, CAT, TNF-α, IL-1ß, p53, and BAX transcripts, and downregulation of Dnmt1 and Dnmt3b transcripts. Thermal stress enhanced transcriptional responses of eight indicator genes following Pb toxicity. The induction of cell death in response to combined exposures was also confirmed in the body of zebrafish by fluorescence intensity image analysis. These data indicated that thermal stress enhanced the poisonous effects of Pb exposure on antioxidant defense, inflammation, and apoptotic mechanisms. Transcriptional inhibition of DNA methylation-related genes might serve as a crucial factor contributing to the possibility of epigenetic adaptation by altering combined stress. We suggest that a careful evaluation of the potential effects of climate change (especially temperature) should be considered when investigating the toxic levels of metal pollution, such as Pb, in an aquatic environment.

Heat shocks T cells down a path to disease.

Febrile temperatures enhance differentiation of CD4+ T cells into pathogenic TH17 cells that contribute to autoimmune disease.

Immune response to acute heat stress in the intestine of the red swamp crayfish, Procambarus clarkii.

High temperature is an important environmental factor that affects the survival and immunity of aquatic animals. The intestine of crustaceans is their first line of defense, and the physiological homeostasis of this organ can be influenced by high temperature stress. The red swamp crayfish Procambarus clarkii is an important commercial aquaculture species in China, but little is known about its intestinal immune response to acute heat stress. In this study, we investigated the intestinal immune response of P. clarkii individuals that were assigned to the control (25 °C) and heat stress (35 °C) groups. Biochemical assays were conducted for the oxidative stress parameters ·O2- generation capacity, lipid peroxide content, and malondialdehyde content; the activities of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase; and the activities of the immunity-related enzymes alkaline phosphatase, acid phosphatase, and lysozyme. The relative expression level of the antioxidant genes heat shock protein 70 (hsp70), ferritin (fer), and metallothione (met) was examined by RT-PCR. Based on the data obtained, all the parameters tended to increase, peak and then decrease with time, and were significantly different between the two groups (P < 0.05). These findings reveal that acute heat stress adversely affects the antioxidant status and immune function in the P. clarkii intestine. They lay the groundwork for future studies on the effect of rising water temperatures on immune function and survival of this species.

Febrile Temperature Critically Controls the Differentiation and Pathogenicity of T Helper 17 Cells.

Fever, an evolutionarily conserved physiological response to infection, is also commonly associated with many autoimmune diseases, but its role in T cell differentiation and autoimmunity remains largely unclear. T helper 17 (Th17) cells are critical in host defense and autoinflammatory diseases, with distinct phenotypes and pathogenicity. Here, we show that febrile temperature selectively regulated Th17 cell differentiation in vitro in enhancing interleukin-17 (IL-17), IL-17F, and IL-22 expression. Th17 cells generated under febrile temperature (38.5°C-39.5°C), compared with those under 37°C, showed enhanced pathogenic gene expression with increased pro-inflammatory activities in vivo. Mechanistically, febrile temperature promoted SUMOylation of SMAD4 transcription factor to facilitate its nuclear localization; SMAD4 deficiency selectively abrogated the effects of febrile temperature on Th17 cell differentiation both in vitro and ameliorated an autoimmune disease model. Our results thus demonstrate a critical role of fever in shaping adaptive immune responses with implications in autoimmune diseases.

Dendritic Cells Loaded with Heat Shock-Conditioned Ovarian Epithelial Carcinoma Cell Lysates Elicit T Cell-Dependent Antitumor Immune Responses In Vitro.

Ovarian epithelial carcinoma (OEC) is the most frequent ovarian tumor, characterized by a high mortality in advanced stages where conventional therapies are not effective. Based on the role of the immune system in the progression of this disease, immunotherapy using checkpoint blockade has been considered as a therapeutic alternative. Nevertheless, its results do not match up to the positive results in entities like melanoma and other malignancies, suggesting the need to find other therapies to be used alone or in combination. Dendritic cell- (DC-) based vaccines have shown promising results in several types of cancer, such as melanoma, prostate, and lung cancers, due to the essential role played by DCs in the activation of specific T cells, thus using other ways of activating the immune response than immune checkpoint blockade. During the last decade, we have used DC-based vaccines loaded with an allogeneic heat shock-conditioned melanoma cell lysate in the treatment of advanced stage patients in a series of clinical trials. In these studies, 60% of treated patients showed immunological responses which correlated positively with improved survival. Considering the relevance of ovarian cancer and the promising results of our DC-based vaccine, we show here that heat shock-conditioned cell lysates derived from ovarian epithelial carcinoma cell lines have the potential to induce the phenotypic and functional maturation of human DC, which in turn, is able to induce an efficient CD4+ and CD8+ T cell-mediated immune responses against ovarian cancer cell lines in vitro. In summary, OEC heat shock-conditioned cell lysate-loaded DCs may be considered for future combined immunotherapy approaches against ovarian tumors.

Bacterial DNA induces the formation of heat-resistant disease-associated proteins in human plasma.

Our study demonstrated for the first time that bacterial extracellular DNA (eDNA) can change the thermal behavior of specific human plasma proteins, leading to an elevation of the heat-resistant protein fraction, as well as to de novo acquisition of heat-resistance. In fact, the majority of these proteins were not known to be heat-resistant nor do they possess any prion-like domain. Proteins found to become heat-resistant following DNA exposure were named "Tetz-proteins". Interestingly, plasma proteins that become heat-resistant following treatment with bacterial eDNA are known to be associated with cancer. In pancreatic cancer, the proportion of proteins exhibiting eDNA-induced changes in thermal behavior was found to be particularly elevated. Therefore, we analyzed the heat-resistant proteome in the plasma of healthy subjects and in patients with pancreatic cancer and found that exposure to bacterial eDNA made the proteome of healthy subjects more similar to that of cancer patients. These findings open a discussion on the possible novel role of eDNA in disease development following its interaction with specific proteins, including those involved in multifactorial diseases such as cancer.