Chronic heat stress weakened the innate immunity and increased the virulence of highly pathogenic avian influenza virus H5N1 in mice

Repeated activation of preoptic area recipient neurons in posterior paraventricular nucleus mediates chronic heat-induced negative emotional valence and hyperarousal states

Mental and behavioral disorders are associated with extended period of hot weather as found in heatwaves, but the underlying neural circuit mechanism remains poorly known. The posterior paraventricular thalamus (pPVT) is a hub for emotional processing and receives inputs from the hypothalamic preoptic area (POA), the well-recognized thermoregulation center. The present study was designed to explore whether chronic heat exposure leads to aberrant activities in POA recipient pPVT neurons and subsequent changes in emotional states. By devising an air heating paradigm mimicking the condition of heatwaves and utilizing emotion-related behavioral tests, viral tract tracing, in vivo calcium recordings, optogenetic manipulations, and electrophysiological recordings, we found that chronic heat exposure for 3 weeks led to negative emotional valence and hyperarousal states in mice. The pPVT neurons receive monosynaptic excitatory and inhibitory innervations from the POA. These neurons exhibited a persistent increase in neural activity following chronic heat exposure, which was essential for chronic heat-induced emotional changes. Notably, these neurons were also prone to display stronger neuronal activities associated with anxiety responses to stressful situations. Furthermore, we observed saturated neuroplasticity in the POA-pPVT excitatory pathway after chronic heat exposure that occluded further potentiation. Taken together, long-term aberration in the POA to pPVT pathway offers a neurobiological mechanism of emotional and behavioral changes seen in extended periods of hot weather like heatwaves.

Chronic heat stress upregulates pyruvate metabolic process and gluconeogenesis but downregulates immune responses in Sahiwal cattle

Climate change and growing population and their strain on animal production are the impending challenges that the developing countries, like India, need to tackle in the coming days. This study aimed to detect and analyze the uncharacterized variation in the gene expression patterns with the change of condition, from thermoneutral to chronic hot-humid, in the Sahiwal cattle, one of the best breeds of milk-producing cattle in India, known for being heat-tolerant. Using RNA-Seq analysis on peripheral blood mononuclear cells (PBMCs), 4021 differentially expressed mRNAs (2772 upregulated, 1249 downregulated) and 1303 differentially expressed long non-coding RNAs (769 upregulated, 534 downregulated) were identified, with the thresholds of false discovery rate < 0.05 and|log2(fold change)| > 2. Significantly (p-adjusted < 0.05) overrepresented Gene Ontology (GO) terms, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathways were analyzed, revealing upregulation of processes like pyruvate metabolic process, gluconeogenesis, ion transmembrane transport, neuropeptide signaling pathway, and animal organ development, with genes like SHH, GRK1, CHRM3, CAMK2A, and HSPB7 were upregulated, while translation and immune responses, with genes like RPS3, EEF1A1, TNF, BoLA-DRB3, and UBB were downregulated. Analysis of cis-mRNAs of DE-lncRNAs showed presence of both up- and down-regulated cis-mRNAs for both up- and down-regulated lncRNAs indicating existence of positive and negative regulation of mRNA expression by lncRNAs. Managemental nudges that decrease metabolic heat generation, like betaine and chromium supplementation, and increase heat dissipation, like microenvironment cooling, should be utilized. This study highlights the role of pyruvate metabolism and gluconeogenesis in coping up with heat stress and offers an improved understanding of the heat stress response of Sahiwal cattle along with the genes and pathways responsible for it.

Whole genome discovery of regulatory genes responsible for the response of chicken to heat stress

Long noncoding RNAs (lncRNAs) are functional bridges connecting the genome with phenotypes by interacting with DNA, mRNA, and proteins. Using publically available acute heat stress (AHS)-related RNA-seq data, we discovered novel lncRNAs and tested their association with AHS along with ~ 8800 known lncRNAs and ~ 28,000 mRNA transcripts. Our pipeline discovered a total of 145 potentially novel-lncRNAs. One of them (Fishcomb_p-value = 0.06) along with another novel transcript (annotated as protein-coding; Fishcomb_p-value = 0.03) were identified as significantly associated with AHS. We found five known-lncRNAs and 134 mRNAs transcripts that were significantly associated with AHS. Four novel lncRNAs interact cis-regulated with 12 mRNA transcripts and are targeted by 11 miRNAs. Also six meta-lncRNAs associate with 134 meta-mRNAs through trans-acting co-expression, each targeted by 15 and 216 miRNAs, respectively. Three of the known-lncRNAs significantly co-expressed with almost 97 of the significant mRNAs (Pearson correlation p-value < 0.05). We report the mentioned three known-lncRNAs (ENSGALT00000099876, ENSGALT00000107573, and ENSGALT00000106323) as the most, significantly regulatory elements of AHS in chicken. It can be concluded that in order to alleviate the adverse effects of AHS on chicken, the manipulation of the three regulatory lncRNAs could lead to a more desirable result than the manipulation of the most significant mRNAs.

Exploring candidate genes for heat tolerance in ovine through liver gene expression

Thermotolerance has become an essential factor in the prevention of the adverse effects of heat stress, but it varies among animals. Identifying genes related to heat adaptability traits is important for improving thermotolerance and for selecting more productive animals in hot environments. The primary objective of this research was to find candidate genes in the liver that play a crucial role in the heat stress response of Santa Ines sheep, which exhibit varying levels of heat tolerance. To achieve this goal, 80 sheep were selected based on their thermotolerance and placed in a climate chamber for 10 days, during which the average temperature was maintained at 36 °C from 10 a.m. to 4 p.m. and 28 °C from 4 p.m. to 10 a.m. A subset of 14 extreme animals, with seven thermotolerant and seven non-thermotolerant animals based on heat loss (rectal temperature), were selected for liver sampling. RNA sequencing and differential gene expression analysis were performed. Thermotolerant sheep showed higher expression of genes GPx3, RGS6, GPAT3, VLDLR, LOC101108817, and EVC. These genes were mainly related to the Hedgehog signaling pathway, glutathione metabolism, glycerolipid metabolism, and thyroid hormone synthesis. These enhanced pathways in thermotolerant animals could potentially mitigate the negative effects of heat stress, conferring greater heat resistance.

Involvement of transcriptional co-activator p300 in upregulated expression of HSP70 by aquareovirus non-structural protein NS31

Members of Aquareovirus genus, including grass carp reovirus (GCRV), contribute to a serious threat to aquaculture animals accompanied by stress response. Our previous reports revealed that GCRV nonstructural protein NS31 serves as a potent contributor for virus selectively up-regulating specific heat shock protein 70-kd gene（HSP70），however，the mechanism by which inducing HSP70 gene expression is unknown. In this study, we further found that either the N- or C-terminal domain of GCRV NS31 is responsible for enhancing fish HSP70 promoter transcription, and recombinant NS31 protein purified from baculovirus expression system seems to not directly bind HSP70 basic promoter in vitro by an electrophoretic mobility shift assay. However, the transcriptional co-activator p300 was identified as a potential interacting partner for NS31 by pull-down assay. Moreover, knock-down of p300 or addition of p300 inhibitor resulted in obviously reduced HSP70 expression by NS31 or GCRV infection suggesting that the well-characterized heat-shock-responsive HSF1/p300 transcriptional complex might involve in the induction of HSP70. These results collectively reveal this aquareovirus generates cell stress response through its nonstructural protein NS31 recruiting transcriptional co-activator p300.

The change in the relationship between temperature and respiratory diseases among children in Guangzhou, China

Temperature is closely associated with respiratory disease (RD) in children, but few studies have examined whether the relationship between ambient temperature and RD in children changed after the COVID-19 epidemic. The aim of this study was to assess the relationship between temperature and RD in children after the COVID-19 epidemic in Guangzhou, China. We used a distributed lag nonlinear model to compare the relationship between temperature and RD among children in Guangzhou from 2018 to 2022. The results showed an S-shaped relationship between temperature and RD in the post-COVID-19 period with a reference minimum risk at a temperature of 21 °C and an increasing relative risk (RR) at extremely low temperature (ELT) and extremely high temperature (EHT). The highest RR associated with EHT was 1.935 (95% confidence interval [CI]: 1.314-2.850) at a lag of 0-14 days. The on-the-day lag effects were found to be strongest at the lag 0 day of EHT with a RR of 1.167 (95% CI: 1.021-1.334). Furthermore, each 1 °C increase in post-COVID-19 temperature increased the risk of RD by 8.2% (95% CI: 1.044-1.121). Our study provides evidence that the relationship between temperature and RD in children in Guangzhou changed after the COVID-19 epidemic, and high temperature is more likely to cause RD in children. Relevant government departments and parents should understand the relationship between temperature and RD in children and develop new preventive measures.

The impact of stress and anesthesia on animal models of infectious disease

Stress and general anesthesia have an impact on the functional response of the organism due to the detrimental effects on cardiovascular, immunological, and metabolic function, which could limit the organism's response to an infectious event. Animal studies have formed an essential step in understanding and mitigating infectious diseases, as the complexities of physiology and immunity cannot yet be replicated in vivo. Using animals in research continues to come under increasing societal scrutiny, and it is therefore crucial that the welfare of animals used in disease research is optimized to meet both societal expectations and improve scientific outcomes. Everyday management and procedures in animal studies are known to cause stress, which can not only cause poorer welfare outcomes, but also introduces variables in disease studies. Whilst general anesthesia is necessary at times to reduce stress and enhance animal welfare in disease research, evidence of physiological and immunological disruption caused by general anesthesia is increasing. To better understand and quantify the effects of stress and anesthesia on disease study and welfare outcomes, utilizing the most appropriate animal monitoring strategies is imperative. This article aims to analyze recent scientific evidence about the impact of stress and anesthesia as uncontrolled variables, as well as reviewing monitoring strategies and technologies in animal models during infectious diseases.

Risk Factors for Respiratory Viral Infections: A Spotlight on Climate Change and Air Pollution

Climate change has both direct and indirect effects on human health, and some populations are more vulnerable to these effects than others. Viral respiratory infections are most common illnesses in humans, with estimated 17 billion incident infections globally in 2019. Anthropogenic drivers of climate change, chiefly the emission of greenhouse gases and toxic pollutants from burning of fossil fuels, and the consequential changes in temperature, precipitation, and frequency of extreme weather events have been linked with increased susceptibility to viral respiratory infections. Air pollutants like nitrogen dioxide, particulate matter, diesel exhaust particles, and ozone have been shown to impact susceptibility and immune responses to viral infections through various mechanisms, including exaggerated or impaired innate and adaptive immune responses, disruption of the airway epithelial barrier, altered cell surface receptor expression, and impaired cytotoxic function. An estimated 90% of the world's population is exposed to air pollution, making this a topic with high relevance to human health. This review summarizes the available epidemiologic and experimental evidence for an association between climate change, air pollution, and viral respiratory infection.

The Role of BTBD7 in Normal Development and Tumor Progression

BTB/POZ domain-containing protein 7 (BTBD7) has a relative molecular weight of 126KD and contains two conserved BTB/POZ protein sequences. BTBD7 has been shown to play an essential role in normal human development, precancerous lesions, heat-stress response, and tumor progression. BTBD7 promotes branching morphogenesis during development and participates in the salivary gland, lung, and tooth formation. Furthermore, many studies have shown that aberrant expression of BTBD7 promotes heat stress response and the progression of precancerous lesions. BTBD7 has also been found to play an important role in cancer. High expression of BTBD7 affects tumor progression by regulating multiple pathways. Therefore, a complete understanding of BTBD7 is crucial for exploring human development and tumor progression. This paper reviews the research progress of BTBD7, which lays a foundation for the application of BTBD7 in regenerative medicine and as a biomarker for tumor prediction or potential therapeutic target.

Effects of chronic heat stress on the immunophenotyping of lymphocytes in immune organs of growing pigs

This study aimed to investigate the effects of chronic heat stress on the immunophenotyping of lymphocytes in immune organs of growing pigs. A single-factor randomized block design was used, and 15 healthy growing large white barrows (5 litters, 3 pigs/litter) with similar body weight (40.8 kg) were assigned into 3 groups (5 pigs in each group). Groups were: control group (Con, in 23 °C environmental control chamber, fed ad libitum), heat stress group (HS, in 33 °C environmental control chamber, fed ad libitum), and pair-fed group (PF, in 23 °C environmental control chamber, fed diets according to the feed intake of HS group). After a 7-d adaption, the experiment lasted for 21 d. The results showed as follows: (1) activated T cells in the thymus of HS pigs were higher than those in PF pigs (P < 0.05). Monocytes and dendritic cells in the thymus of HS pigs were significantly higher than that in Con and PF pigs (P < 0.05), while the proportions of these 2 lymphocytes in the thymus of Con pigs did not differ from PF pigs (P > 0.05). Compared with Con pigs, the proportion of CD4+ (P < 0.05) and CD8+ T cells (P < 0.10) in the thymus was increased in HS pigs, while the proportion of CD4+ and CD8+ T cells in PF pigs did not differ from Con pigs (P > 0.05). (2) Compared with Con pigs, significantly decreased T cells, increased B cells and monocytes were found in the spleen of pigs exposed to heat stress (P < 0.05); the proportions of these 3 types of lymphocytes were not significantly different between Con and PF pigs (P > 0.05). The proportions of CD4+ T cells and Treg cells in the spleen of pigs exposed to heat stress tended to be lower than those in the Con pigs (P < 0.10). (3) The proportion of lymphocytes in the tonsils of pigs exposed to heat stress did not differ from Con pigs (P > 0.05); compared with PF pigs, the proportion of Treg cells was significantly decreased in HS pigs (P < 0.05). In conclusion, chronic heat stress stimulates the development and maturation of T cells in the pig thymus toward CD4+ and CD8+ T cells and increases the proportion of monocytes and dendritic cells; under the condition of chronic heat stress, the immune response process in the spleen of pigs is enhanced, but chronic heat stress impairs the survival of CD4+ T cells in the spleen.

Weighted single-step GWAS and RNA sequencing reveals key candidate genes associated with physiological indicators of heat stress in Holstein cattle

Background

The study of molecular processes regulating heat stress response in dairy cattle is paramount for developing mitigation strategies to improve heat tolerance and animal welfare. Therefore, we aimed to identify quantitative trait loci (QTL) regions associated with three physiological indicators of heat stress response in Holstein cattle, including rectal temperature (RT), respiration rate score (RS), and drooling score (DS). We estimated genetic parameters for all three traits. Subsequently, a weighted single-step genome-wide association study (WssGWAS) was performed based on 3200 genotypes, 151,486 phenotypic records, and 38,101 animals in the pedigree file. The candidate genes located within the identified QTL regions were further investigated through RNA sequencing (RNA-seq) analyses of blood samples for four cows collected in April (non-heat stress group) and four cows collected in July (heat stress group).

Results

The heritability estimates for RT, RS, and DS were 0.06, 0.04, and 0.03, respectively. Fourteen, 19, and 20 genomic regions explained 2.94%, 3.74%, and 4.01% of the total additive genetic variance of RT, RS, and DS, respectively. Most of these genomic regions are located in the Bos taurus autosome (BTA) BTA3, BTA6, BTA8, BTA12, BTA14, BTA21, and BTA24. No genomic regions overlapped between the three indicators of heat stress, indicating the polygenic nature of heat tolerance and the complementary mechanisms involved in heat stress response. For the RNA-seq analyses, 2627 genes were significantly upregulated and 369 downregulated in the heat stress group in comparison to the control group. When integrating the WssGWAS, RNA-seq results, and existing literature, the key candidate genes associated with physiological indicators of heat stress in Holstein cattle are: PMAIP1, SBK1, TMEM33, GATB, CHORDC1, RTN4IP1, and BTBD7.

Conclusions

Physiological indicators of heat stress are heritable and can be improved through direct selection. Fifty-three QTL regions associated with heat stress indicators confirm the polygenic nature and complex genetic determinism of heat tolerance in dairy cattle. The identified candidate genes will contribute for optimizing genomic evaluation models by assigning higher weights to genetic markers located in these regions as well as to the design of SNP panels containing polymorphisms located within these candidate genes.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00748-6.

Future-proofing the koala: synergising genomic and environmental data for effective species management

Climatic and evolutionary processes are inextricably linked to conservation. Avoiding extinction in rapidly changing environments often depends upon a species' capacity to adapt in the face of extreme selective pressures. Here, we employed exon capture and high-throughput next-generation sequencing to investigate the mechanisms underlying population structure and adaptive genetic variation in the koala (Phascolarctos cinereus), an iconic Australian marsupial that represents a unique conservation challenge because it is not uniformly threatened across its range. An examination of 250 specimens representing 91 wild source locations revealed that five major genetic clusters currently exist on a continental scale. The initial divergence of these clusters appears to have been concordant with the Mid-Brunhes Transition (∼ 430-300 kya), a major climatic reorganization that increased the amplitude of Pleistocene glacial-interglacial cycles. While signatures of polygenic selection and environmental adaptation were detected, strong evidence for repeated, climate-associated range contractions and demographic bottleneck events suggests that geographically isolated refugia may have played a more significant role in the survival of the koala through the Pleistocene glaciation than in situ adaptation. Consequently, the conservation of genome-wide genetic variation must be aligned with the protection of core koala habitat to increase the resilience of threatened populations to accelerating anthropogenic threats. Finally, we propose that the five major genetic clusters identified in this study should be accounted for in future koala conservation efforts (e.g. guiding translocations), as existing management divisions in the states of Queensland and New South Wales do not reflect historic or contemporary population structure.

Effects of Selenium as a Dietary Source on Performance, Inflammation, Cell Damage, and Reproduction of Livestock Induced by Heat Stress: A Review

Heat stress as a result of global warming has harmful consequences for livestock and is thus becoming an urgent issue for animal husbandry worldwide. Ruminants, growing pigs, and poultry are very susceptible to heat stress because of their fast growth, rapid metabolism, high production levels, and sensitivity to temperature. Heat stress compromises the efficiency of animal husbandry by affecting performance, gastrointestinal health, reproductive physiology, and causing cell damage. Selenium (Se) is an essential nutritional trace element for livestock production, which acts as a structural component in at least 25 selenoproteins (SELs); it is involved in thyroid hormone synthesis, and plays a key role in the antioxidant defense system. Dietary Se supplementation has been confirmed to support gastrointestinal health, production performance, and reproductive physiology under conditions of heat stress. The underlying mechanisms include the regulation of nutrient digestibility influenced by gastrointestinal microorganisms, antioxidant status, and immunocompetence. Moreover, heat stress damage to the gastrointestinal and mammary barrier is closely related to cell physiological functions, such as the fluidity and stability of cellular membranes, and the inhibition of receptors as well as transmembrane transport protein function. Se also plays an important role in inhibiting cell apoptosis and reducing cell inflammatory response induced by heat stress. This review highlights the progress of research regarding the dietary supplementation of Se in the mitigation of heat stress, addressing its mechanism and explaining the effect of Se on cell damage caused by heat stress, in order to provide a theoretical reference for the use of Se to mitigate heat stress in livestock.

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.

The Mediation of miR-34a/miR-449c for Immune Cytokines in Acute Cold/Heat-Stressed Broiler Chicken

Simple Summary

In the intensive and scale poultry industry, the level of heat stress (HS) directly affects the growth, development, and production performance of poultry. To alleviate the adverse effects of stress in broilers, microRNA (miRNA) was regarded as a potential regulator of immune cytokines. In this study, through the sequencing analysis of spleens after cold/heat stress, we found that 33 and 37 miRNA were differentially expressed in the heat stress group compared with the normal (NS) group and cold stress (CS) group, respectively. The differential miRNA were mainly involved in biological processes such as the cytokine–cytokine receptor interaction. To further understand the miRNA-mediated effect of heat stress on the immune level of chickens, we selected miR-34a and miR-449c as the research objects, predicted and verified that interleukin 2 (IL-2) and interleukin 12α (IL-12α) were the target genes of miR-34a and miR-449c. Coupled with the analysis of the expression of other cytokines, we found that miRNA could change the expression of immune cytokines directly or indirectly. This discovery provides a new insight into the mediation of miRNA for immune cytokines in acute cold/heat stressed broiler chicken.

Abstract

An increasing amount of evidence has revealed that microRNAs (miRNAs) participated in immune regulation and reaction to acute cold and heat stresses. As a new type of post-transcriptional regulatory factor, miRNA has received widespread attention; However, the specific mechanism used for this regulation still needs to be determined. In this study, thirty broilers at the same growth period were divided into three groups and treated with different temperature and humidity of CS (10–15 °C and 90% Relative Humidity (RH)), HS (39 °C and 90% RH), and NS (26 °C and 50–60% RH) respectively. After 6 h, splenic tissues were collected from all study groups. miRNA sequencing was performed to identify the differentially expressed miRNAs (DEMs) between HS, CS, and NS. We found 33, 37, and 7 DEMs in the HS-NS, HS-CS, CS-NS group. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that DEMs were significantly enriched in cytokine–cytokine receptor interaction and functioned as the cellular responders to stress. We chose two miRNA, miR-34a and miR-449c, from the same family and differential expressed in HS-CS and HS-NS group, as the research objects to predict and verify the target genes. The dual-luciferase reporter assay and quantitative real-time PCR (qRT-PCR) confirmed that two cytokines, IL-2 and IL-12α, were the direct target genes of miR-34a and miR-449c. To further understand the mediation mechanism of miRNAs in acute cold/heat-stressed broiler chicken, a splenic cytokines profile was constructed. The results showed that IL-1β was strongly related to acute heat stress in broiler chicken, and from this we predicted that the increased expression of IL-1β might promote the expression of miR-34a, inducing the upregulation of interferon-γ (INF-γ) and IL-17. Our finds have laid a theoretical foundation for the breeding of poultry resistance and alleviation of the adverse effects of stress.

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.

Translocation of intrauterine-infused bacterial lipopolysaccharides to the mammary gland in dexamethasone-treated goats

Our previous study showed that intrauterine-infused lipopolysaccharide (LPS) can be translocated to the mammary gland to induce weak inflammation. This study aimed to determine whether dexamethasone treatment facilitated the translocation of LPS from the uterus to the mammary gland to induce a heavy inflammatory response. Sixteen goats were divided into control and LPS groups, subjected to daily dexamethasone administration before saline or LPS infusion. Milk and blood samples were collected before and after LPS infusion to determine the milk yield and somatic cell count (SCC) and blood leucocyte count (BLC), cytokines, antimicrobial peptides and serum amyloid A (SAA) concentrations. Mammary gland tissues were collected from two goats before and 24 hr after LPS infusion for immunohistochemical analysis of LPS. The mean SCC in the LPS group was significantly higher, whereas the milk yield was significantly lower than that in the control group after LPS infusion. The mean BLC in the LPS group was significantly lower than in the control group after LPS infusion. Furthermore, milk concentrations of IL-1β, S100A8 and lactoferrin were higher in the LPS group than in the control group after infusion. LPS was detected in the connective tissues and inner alveolar spaces of the mammary glands 24 hr after LPS infusion. We concluded that dexamethasone administration facilitated the translocation of intrauterine-infused LPS to the mammary gland, where it induced an inflammatory response. Therefore, LPS translocated from other organs, such as the uterus, can induce heavy inflammation in the mammary gland under immunosuppressive conditions.

The regulation mechanism of lncRNAs and mRNAs in sea cucumbers under global climate changes: Defense against thermal and hypoxic stresses

The aquatic environment can be greatly impacted by thermal and hypoxic stresses, particularly caused by intensified global warming. Hence, there is an urgency to understand the response mechanisms of marine organisms to adverse environment. Although long non-coding RNAs (lncRNAs) are involved in many biological processes, their roles in stress responses still remain unclear. Here, differentially expressed (DE) lncRNAs and mRNAs were identified as responses to environmental stresses in the economically important sea cucumber, Apostichopus japonicus, and their potential roles were explored. Based on a total of 159, 355 and 495 significantly upregulated genes and 230, 518 and 647 significantly downregulated genes identified in the thermal, hypoxic and combination thermal + hypoxic stress treatments, respectively, we constructed DE-lncRNA-mRNA coexpression networks. Among the networks, eight shared pairs were identified from the three treatments, and based on the connectivity degree, MSTRG.27265, MSTRG.19729 and MSTRG.95524 were shown to be crucial lncRNAs. Among all the significantly changed lncRNAs identified by RT-qPCR and sequencing data, binding sites were found in four other lncRNAs (MSTRG.34610, MSTRG.10941, MSTRG.81281 and MSTRG.93731) with Aja-miR-2013-3p, a key miRNA that responds to hypoxia in sea cucumbers. The hypoxia-inducible factor (HIF-1α) was also shown as the possible targeted mRNA of Aja-miR-2013-3p. As indicated by a dual-luciferase reporter assay system, "HIF-1α gene/Aja-miR-2013-3p/MSTRG.34610" network and the "HIF-1α gene/Aja-miR-2013-3p/MSTRG.10941" network may play important roles in sea cucumbers under environmental stresses. Moreover, environmental stress altered the expression of multiple lncRNAs and mRNAs, thus affecting various biological processes in A. japonicus, including immunity, energy metabolism and the cell cycle. At the molecular level, more comprehensive responses were elicited by the combined thermal/hypoxic stress treatment than by individual stresses alone in sea cucumbers. This study lays the groundwork for future research on molecular mechanisms of echinoderm responses to thermal and hypoxic stress in the context of global climate changes.

Pre-Treatment with Zirconia Nanoparticles Reduces Inflammation Induced by the Pathogenic H5N1 Influenza Virus

Background

New approaches are urgently needed to fight influenza viral infection. Previous research has shown that zirconia nanoparticles can be used as anticancer materials, but their antiviral activity has not been reported. Here, we investigated the antiviral effect of zirconia (ZrO₂) nanoparticles (NPs) against a highly pathogenic avian influenza virus.

Materials and Methods

In this study, the antiviral effects of ZrO₂ on H5N1 virus were assessed in vivo, and the molecular mechanism responsible for this protection was investigated.

Results

Mice treated with 200 nm positively-charged NPs at a dose of 100 mg/kg showed higher survival rates and smaller reductions in weight. 200 nm ZrO₂ activated mature dendritic cells and initially promoted the expression of cytokines associated with the antiviral response and innate immunity. In the lungs of H5N1-infected mice, ZrO₂ treatment led to less pathological lung injury, significant reduction in influenza A virus replication, and overexpression of pro-inflammatory cytokines.

Conclusion

This antiviral study using zirconia NPs shows protection of mice against highly pathogenic avian influenza virus and suggests strong application potential for this method, introducing a new tool against a wide range of microbial infections.

Heat Treatment at an Early Age Has Effects on the Resistance to Chronic Heat Stress on Broilers

This study was conducted to investigate the effects of early heat conditioning on growth performance, liver-specific enzymes (GOT and GPT), neuro-hormones (dopamine and serotonin), stress hormones (corticosterone), and the expression of HSPs (heat shock proteins), HSFs (heat shock factors), and pro-inflammatory cytokines under chronic high temperature. Broilers were raised with commercial feed and supplied with water ad libitum under conventional temperature. We separated the broilers into three groups: the control without any heat exposure (C), chronic heat-stressed group (CH), and early and chronic heat-stressed group (HH). At 5 days of age, the HH group was exposed to high temperatures (40 °C for 24 h), while the remaining groups were raised at a standard temperature. Between days 6 and 20, all three groups were kept under optimal temperature. From 21 to 35 days, the two heat-stressed groups (CH and HH) were exposed to 35 °C. Groups exposed to high temperature (CH and HH) showed significantly lower body weight and feed intake compared to the control. GOT and GPT were lower expressed in the CH and HH groups than the control group. In addition, the protein expressions of HSPs were down-regulated by chronic heat stress (CH and HH groups). The gene expressions of HSP60 and HSF3 were significantly down-regulated in the CH and HH groups, while HSP70 and HSP27 genes were up-regulated only in the HH group compared with the control group. The expression of pro-inflammatory cytokine genes was significantly up-regulated in the HH group compared with the control and CH groups. Thus, exposure of early Heat stress (HS) to broilers may affect the inflammatory response; however, early heat exposure did not have a positive effect on chronic HS of liver enzymes and heat shock protein expression.

p-STAT1 regulates the influenza A virus replication and inflammatory response in vitro and vivo

Influenza A virus infection activates various intracellular signaling pathways, which is mediated by the transcription factors. Here, a quantitative phosphoproteomic analysis of A549 cells after infection with influenza A virus (H5N1) was performed and we found that the transcription factor STAT1 was highly activated. Unexpectedly, upon inhibition of p-STAT1, titers of progeny virus and viral protein synthesis were both reduced. The STAT1 inhibitor Fludarabine (FLUD) inhibited an early progeny step in viral infection and reduced the levels of influenza virus genomic RNA (vRNA). Concomitantly, there was reduced expression of inflammatory cytokines in p-STAT1 inhibited cells. In vivo, suppression of p-STAT1 improved the survival of H5N1 virus-infected mice, reduced the pulmonary inflammatory response and viral burden. Thus, our data demonstrated a critical role for p-STAT1 in influenza virus replication and inflammatory responses. We speculate that STAT1 is an example of a putative antiviral signaling component to support effective replication.

Effect of heat stress on the quantitative expression patterns of different cytokine genes in Malabari goats

A study was conducted to determine the influence of exposure to hot environment on different cytokine gene expression patterns in Malabari goat. The study was conducted in 12 (10 months to 1 year old) goats of Malabari breed for 45-day duration. The control (n = 6; C) group goats were kept under comfortable condition in the shaded pens while heat stress (n = 6; HS) group goats were kept out in the open hot environment during summer season for the study duration between 10.00 h to 16.00 h. The representative mesenteric lymph node (MLN) samples were collected from the slaughtered goats at the end of study for assessing the different cytokine gene expression and histopathological changes. Compared with C group, the expression patterns of interleukin 18 (IL-18), tumor necrosis factor-α (TNF-α), interferon-β (IFN-β), and IFN-γ downregulated (P < 0.05) in the HS group. The histopathological changes of MLNs showed paucity of lymphocyte distribution in follicular areas as wells as decreased density of lymphocytes in the germinal centers of the HS group (P < 0.05). The findings from this study reflected the compromised immune functions during heat stress in Malabari goats. Further, the study established that IL-18, TNF-α, IFN-β, and IFN-γ genes could serve as reliable immunological markers for quantifying heat stress-mediated immune response alterations in Malabari goats.

The role of E3 ubiquitin ligase seven in absentia homolog in the innate immune system: An overview

The innate immune system has been considered as an ancient system and less important than the adaptive immune system. However, the interest in innate immunity has grown significantly in the past few years marked by the identification of Toll-like receptors, a member of pattern recognition receptors (PRRs). The PRRs are crucial for the identification of self- and non-self-antigen and play a role in the initiation of signaling events that activate the effective immune response. These sensor signals through interweaving signaling cascades which result in the production of interferons and cytokines as the effector of immune system. Ubiquitin and ubiquitin-like modifiers (UBLs) actively mediate the rapid and versatile regulatory processes that initiate the activation of the innate immune system cascade. The seven in absentia homolog (SIAH) is a potent RING finger E3 ubiquitin ligase that is known to involve in several stress responses, including hypoxia, oxidative stress, DNA damage stress, and inflammation. In this review, the role of SIAH will be discussed as an E3 ubiquitin ligase on the regulation of innate immune.

Deep Transcriptomic Analysis of Black Rockfish (Sebastes schlegelii) Provides New Insights on Responses to Acute Temperature Stress

In the present study, we conducted an RNA-Seq analysis to characterize the genes and pathways involved in acute thermal and cold stress responses in the liver of black rockfish, a viviparous teleost that has the ability to cope with a wide range of temperature changes. A total of 584 annotated differentially expressed genes (DEGs) were identified in all three comparisons (HT vs NT, HT vs LT and LT vs NT). Based on an enrichment analysis, DEGs with a potential role in stress accommodation were classified into several categories, including protein folding, metabolism, immune response, signal transduction, molecule transport, membrane, and cell proliferation/apoptosis. Considering that thermal stress has a greater effect than cold stress in black rockfish, 24 shared DEGs in the intersection of the HT vs LT and HT vs NT groups were enriched in 2 oxidation-related gene ontology (GO) terms. Nine important heat-stress-reducing pathways were significantly identified and classified into 3 classes: immune and infectious diseases, organismal immune system and endocrine system. Eight DEGs (early growth response protein 1, bile salt export pump, abcb11, hsp70a, rtp3, 1,25-dihydroxyvitamin d(3) 24-hydroxylase, apoa4, transcription factor jun-b-like and an uncharacterized gene) were observed among all three comparisons, strongly implying their potentially important roles in temperature stress responses.

Immunomodulatory effects of phytogenics in chickens and pigs - A review

Environmental stressors like pathogens and toxins may depress the animal immune system through invasion of the gastrointestinal tract (GIT) tract, where they may impair performance and production, as well as lead to increased mortality rates. Therefore, protection of the GIT tract and improving animal health are top priorities in animal production. Being natural-sourced materials, phytochemicals are potential feed additives possessing multiple functions, including: anti-inflammatory, anti-fungal, anti-viral and antioxidative properties. This paper focuses on immunity-related physiological parameters regulated by phytochemicals, such as carvacrol, cinnamaldehyde, curcumin, and thymol; many studies have proven that these phytochemicals can improve animal performance and production. On the molecular level, the impact of inflammatory gene expression on underlying mechanisms was also examined, as were the effects of environmental stimuli and phytochemicals in initiating nuclear factor kappa B and mitogen-activated protein kinases signaling pathways and improving health conditions.

The Superimposed Deubiquitination Effect of OTULIN and Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Nsp11 Promotes Multiplication of PRRSV

Linear ubiquitination plays an important role in the regulation of the immune response by regulating nuclear factor κB (NF-κB). The linear ubiquitination-specific deubiquitinase ovarian tumor domain deubiquitinase with linear linkage specificity (OTULIN) can control the immune signaling transduction pathway by restricting the Met1-linked ubiquitination process. In our study, the porcine OTLLIN gene was cloned and deubiquitin functions were detected in a porcine reproductive and respiratory syndrome virus (PRRSV)-infected-cell model. PRRSV infection promotes the expression of the OTULIN gene; in turn, overexpression of OTULIN contributes to PRRSV proliferation. There is negative regulation of innate immunity with OTULIN during viral infection. The cooperative effects of swine OTULIN and PRRSV Nsp11 potentiate the ability to reduce levels of cellular protein ubiquitin associated with innate immunity. Importantly, PRRSV Nsp11 recruits OTULIN through a nonenzymatic combination to enhance its ability to remove linear ubiquitination targeting NEMO, resulting in a superimposed effect that inhibits the production of type I interferons (IFNs). Our report presents a new model of virus utilization of the ubiquitin-protease system in vivo from the perspective of the viral proteins that interact with cell deubiquitination enzymes, providing new ideas for prevention and control of PRRSV.IMPORTANCE Deubiquitination effects of swine OTULIN were identified. The interaction between porcine OTULIN and PRRSV Nsp11 is dependent on the OTU domain. PRRSV Nsp11 recruits OTULIN through a nonenzymatic combination to promote removal of linear ubiquitination targeting NEMO, resulting in a superimposed effect that inhibits the production of type I IFNs.

[Pathomorphism of Hantavirus infection under prolonged heat stress]

AIM

to provide the morphological characteristics of experimental Hantavirus infection under heat stress conditions to identify the possibilities of its modeling in resistant laboratory animals.

MATERIAL AND METHODS

Experiments were carried out on outbred albino mice that were divided into 4 groups: 1) intact mice unexposed to heating; 2) those exposed to heating; 3) Hantavirus-infected animals unexposed to preheating; 4) those exposed to preheating. The animals in Groups 2-4 were long exposed to heat stress at a temperature of 30 °C for 3 hours during 3 days. Strain Aa 60343 (PM-79-95) of the Far East genovariant of Hantaan virus (the genus Hantavirus, family Bunyaviridae) from the collection of the G.P. Somov Research Institute of Epidemiology and Microbiology was used to induce infection. The animals in Groups 3 and 4 were intraperitoneally injected with 700 FFU of Hantavirus per mouse. Materials (lung, liver, kidney, and spleen) taken from Groups 2-4 animals were collected for histological examination on days 1, 3, 7 and 14 of observation.

RESULTS

The intact albino mice in Group 1 showed no histopathological changes in the organs. After heat exposure, Group 2 animals were found to have an immunomorphological response in the interstitial tissues of the lung, liver and kidney in partial lymphoid hypoplasia of the spleen. There were no signs of inapparent infection in the presence of marked immunomorphological changes in the organs in Group 3 of hantavirus-infected animals unexposed to preheating. In Group 4, those exposed to preheating exhibited dystrophic and destructive changes in the target organs (lungs, kidneys) in the presence of immunodeficiency manifestations of manifestations that were more pronounced in dead animals.

CONCLUSION

In an unresponsive model (adult albino mice), Hantavirus infection caused only obvious immunomorphological changes in the organs. Prolonged preheat stress in the hantavirus-infected animals promoted inapparent infection and morphological manifestations of induced secondary immunodeficiency that was responsible for the manifestation of an infectious process in some animals.

Short-Term Heat Shock Affects Host-Virus Interaction in Mice Infected with Highly Pathogenic Avian Influenza Virus H5N1

Highly pathogenic avian influenza virus (HPAIV) H5N1 is a highly contagious virus that can cause acute respiratory infections and high human fatality ratio due to excessive inflammatory response. Short-term heat shock, as a stressful condition, could induce the expression of heat shock proteins that function as molecular chaperones to protect cells against multiple stresses. However, the protective effect of short-term heat shock in influenza infection is far from being understood. In this study, mice were treated at 39°C for 4 h before being infected with HPAIV H5N1. Interestingly, short-term heat shock significantly increased the levels of HSP70 and pro-inflammatory cytokines IL-6, TNF-α, IFN-β, and IFN-γ in the lung tissues of mice. Following HPAIV H5N1 infection, short-term heat shock alleviated immunopathology and viral replication in lung tissue and repressed the weight loss and increased the survival rate of H5N1-infected mice. Our data reported that short-term heat shock provided beneficial anti-HPAIV H5N1 properties in mice model, which offers an alternative strategy for non-drug prevention for influenza infection.

Heat dissipation does not suppress an immune response in laboratory mice divergently selected for basal metabolic rate (BMR)

The capacity for heat dissipation is considered to be one of the most important constraints on rates of energy expenditure in mammals. To date, the significance of this constraint has been tested exclusively under peak metabolic demands, such as during lactation. Here, we used a different set of metabolic stressors, which do not induce maximum energy expenditures and yet are likely to expose the potential constraining effect of heat dissipation. We compared the physiological responses of mice divergently selected for high (H-BMR) and low basal metabolic rate (L-BMR) to simultaneous exposure to the keyhole limpet haemocyanin (KLH) antigen and high ambient temperature (Ta). At 34°C (and at 23°C, used as a control), KLH challenge resulted in a transient increase in core body temperature (Tb) in mice of both line types (by approximately 0.4°C). Warm exposure did not produce line-type-dependent differences in Tb (which was consistently higher by ca. 0.6°C in H-BMR mice across both Ta values), nor did it result in the suppression of antibody synthesis. These findings were also supported by the lack of between-line-type differences in the mass of the thymus, spleen or lymph nodes. Warm exposure induced the downsizing of heat-generating internal organs (small intestine, liver and kidneys) and an increase in intrascapular brown adipose tissue mass. However, these changes were similar in scope in both line types. Mounting a humoral immune response in selected mice was therefore not affected by ambient temperature. Thus, a combined metabolic challenge of high Ta and an immune response did not appreciably compromise the capacity to dissipate heat, even in the H-BMR mice.

Microarray analysis of intestinal immune-related gene expression in heat-stressed rats

PURPOSE

This study aimed to investigate immune-related gene expression in rat small intestine after heat stress.

MATERIALS AND METHODS

Twelve Sprague Dawley (SD) rats were randomly divided into control and heat-stressed groups. Rats in both groups were housed at 25 °C with 60% relative humidity. The heat-stressed group was subjected to 40 °C for 2 h/day for 3 days. After heat stress, the mRNA expression profile of small intestine epithelial tissue was evaluated by microarray analysis.

RESULTS

A total of 23 genes related to immune responses were significantly altered, of which 12 genes were up-regulated and 11 genes were down-regulated.

CONCLUSIONS

Microarray analysis demonstrated the JAK-STAT pathway had a potentially important role in the regulation of inflammation in the small intestine, and changes in antigen presentation might reduce intestinal immune responses after heat stress.

Will Global Climate Change Alter Fundamental Human Immune Reactivity: Implications for Child Health?

The human immune system is an interface across which many climate change sensitive exposures can affect health outcomes. Gaining an understanding of the range of potential effects that climate change could have on immune function will be of considerable importance, particularly for child health, but has, as yet, received minimal research attention. We postulate several mechanisms whereby climate change sensitive exposures and conditions will subtly impair aspects of the human immune response, thereby altering the distribution of vulnerability within populations-particularly for children-to infection and disease. Key climate change-sensitive pathways include under-nutrition, psychological stress and exposure to ambient ultraviolet radiation, with effects on susceptibility to infection, allergy and autoimmune diseases. Other climate change sensitive exposures may also be important and interact, either additively or synergistically, to alter health risks. Conducting directed research in this area is imperative as the potential public health implications of climate change-induced weakening of the immune system at both individual and population levels are profound. This is particularly relevant for the already vulnerable children of the developing world, who will bear a disproportionate burden of future adverse environmental and geopolitical consequences of climate change.

Association of climate variability and childhood diarrhoeal disease in rural Bangladesh, 2000-2006

This study examined the effects of meteorological factors, particularly, extreme weather events, on the prevalence of childhood diarrhoeal disease in Matlab, Bangladesh. Logistic regression models were used to examine impacts of temperature, rainfall and the extreme weather factors (the number of hot days and days with heavy rainfall) on childhood diarrhoea from 2000 to 2006 at the bari (cluster of dwellings) level. The results showed that the increases in the number of hot days and days with heavy rainfall were associated with an increase in daily diarrhoea cases by 0·8-3·8% and 1-6·2%, respectively. The results from multivariable stepwise models showed that the extreme weather factors were still positively associated with childhood diarrhoea, while the associations for average temperature and rainfall could be negative after other variables were controlled. The findings showed that not only the intensity, but also the frequency of extreme weather events had significant effects on childhood diarrhoea.

Immunomodulatory effect of Lactococcus lactis JCM5805 on human plasmacytoid dendritic cells

Plasmacytoid dendritic cells (pDCs) play a crucial role in anti-viral immunity through production of large amounts of interferons (IFNs). A previous study revealed the existence of lactic acid bacteria that directly stimulate pDCs in mice. In this study, we demonstrated that Lactococcus lactis JCM5805 activates human pDCs and induces IFN production in vitro. In addition, our randomized, placebo-controlled, double blind test showed that yogurt fermented with L. lactis JCM5805 activated pDC activity in vivo. This effect was greater in low pDC subjects, and their ability to produce IFNs was increased from the beginning. Furthermore, the risk of morbidity from the common cold was suppressed in the L. lactis JCM5805 group compared with the placebo group. In conclusion, intake of L. lactis JCM5805 can directly activate pDCs and increase the ability to produce IFNs in vivo. Therefore, L. lactis JCM5805 may be a beneficial tool to enhance anti-viral immunity in humans.

Chronic heat stress inhibits immune responses to H5N1 vaccination through regulating CD4⁺ CD25⁺ Foxp3⁺ Tregs

Chronic heat stress (CHS) is known to have negative impacts on the immune responses in animals and increases their susceptibility to infections including the highly pathogenic avian influenza virus H5N1. However, the role of regulatory T cells (Tregs) in CHS immunosuppression remains largely undefined. In this study, we demonstrated a novel mechanism by which CHS suppressed both Th1 and Th2 immune responses and dramatically decreased the protective efficacy of the formalin-inactivated H5N1 vaccine against H5N1 influenza virus infection. This suppression was found to be associated with the induced generation of CD4⁺CD25⁺FoxP3⁺ Tregs and the increased secretions of IL-10 and TGF-β in CD4⁺ T cells. Adoptive transfer of the induced Tregs also suppressed the protective efficacy of formalin-inactivated H5N1 virus immunization. Collectively, this study identifies a novel mechanism of CHS immunosuppression mediated by regulating CD4⁺CD25⁺Foxp3⁺ Tregs.