Potential roles for pattern molecule of PAMP-triggered immunity in improving crop cold tolerance.

KEY MESSAGE: The application of flagellin 22 (flg22), the most widely studied PAMP, enhance crop cold tolerance. ICE1-CBF pathway and SA signaling is involved in the alleviation of cold injury by flg22 treatment. Pathogen infection cross-activates cold response and increase cold tolerance of host plants. However, it is not possible to use the infection to increase cold tolerance of field plants. Here flagellin 22 (flg22), the most widely studied PAMP (pathogen-associated molecular patterns), was used to mimic the pathogen infection to cross-activate cold response. Flg22 treatment alleviated the injury caused by freezing in Arabidopsis, oilseed and tobacco. In Arabidopsis, flg22 activated the expression of immunity and cold-related genes. Moreover, the flg22 induced alleviation of cold injury was lost in NahG transgenic line (SA-deficient), sid2-2 and npr1-1 mutant plants, and flg22-induced expression of cold tolerance-related genes, which indicating that salicylic acid signaling pathway is required for the alleviation of cold injury by flg22 treatment. In short flg22 application can be used to enhance cold tolerance in field via a salicylic acid-depended pathway.

Childhood co-exposure of cold stress and PM2.5 aggravates the susceptibility and severity of asthma in adulthood of mice.

Both cold stress and ambient fine particle particulate matter (PM2.5 ) has been reported to aggravate and induce respiratory problems like asthma, but the mechanism involved in that has not been fully understood. Therefore, the present study is to explore the mechanism involved in the increased susceptibility and severity of asthma caused by cold stress and PM2.5 exposure. Urban PM2.5 of Shanghai was concentrated to simulate a PM2.5 -polluted environment with an average concentration of 400 µg/m3 , where 1-month young C57BL/6J mice were exposed for 2 months under cold stress (2°C). Co-exposure of cold stress and PM2.5 in childhood of mice led to significant infiltration of inflammatory cells in the peribronchial region or airspaces and the thickening or fibrosis of alveolar septum, increased OVA-specific IgE in serum and total cells, eosinophil cells, and the levels of inflammatory cytokines including IL-4, IL-8, IL-1ß, IL-5, IL-13, and IFN-γ in bronchoalveolar lavage fluid (BALF) of asthma mice. Moreover, mice in co-exposure group presented a significantly high cough feature, reduced catalase (CAT), glutathione (GSH), superoxide dismutase (SOD), and elevated malonaldehyde (MDA) elevated in BALF; increased ratio of Th2/Th1 and the markable inhibition of Th17 differentiation toward Treg cells in the adulthood of asthma mice. Cold stress and PM2.5 co-exposure in childhood may promote the deterioration of asthma symptoms in adulthood of mice by increasing inflammatory cytokines, ROS formation, Th2/Th1 imbalance, and suppressing the differentiation of Th17 toward Treg cells, which will help to provide experimental references when making some therapeutic strategies in allergic diseases through focusing on some natural solutions.

Thermoneutrality and Immunity: How Does Cold Stress Affect Disease?

One of the major challenges the scientific community faces today is the lack of translational data generated from mouse trials for human health application. Housing temperature-dependent chronic cold stress in laboratory rodents is one of the key factors contributing to lack of translatability because it reveals major metabolic differences between humans and rodents. While humans tend to operate at temperatures within their thermoneutral zone, most laboratory rodents are housed at temperatures below this zone and have an increased energy demand to generate heat. This has an impact on the immune system of mice and thus affects results obtained using murine models of human diseases. A limited number of studies and reviews have shown that results obtained on mice housed at thermoneutrality were different from those obtained from mice housed in traditional housing conditions. Most of those studies, focused on obesity and cancer, found that housing mice at thermoneutrality changed the outcomes of the diseases negatively and positively, respectively. In this review, we describe how thermoneutrality impacts the immune system of rodents generally and in the context of different disease models. We show that thermoneutrality exacerbates cardiovascular and auto-immune diseases; alleviates asthma and Alzheimer's disease; and, changes gut microbiome populations. We also show that thermoneutrality can have exacerbating or alleviating effects on the outcome of infectious diseases. Thus, we join the call of others in this field to urge researchers to refine murine models of disease and increase their translational capacity by considering housing at thermoneutrality for trials involving rodents.

Cold stress promotes IL-33 expression in intestinal epithelial cells to facilitate food allergy development.

BACKGROUND: The causative factors and pathogenesis of food allergy (FA) is not fully understood yet. Cold stress (CS) occurs frequently in human life that influences physiological activities in the body. In this study, we aimed to investigate the chronic CS (CS) effects on promoting the expression of IL-33 in intestinal epithelial cells. METHODS: CS was carried out by placing mice at 4 °C for 1 h daily for 7 consecutive days. We developed a mouse model used to test the effects of CS on the FA development. RESULTS: We found that, similar to conventional FA mouse model, CS induced the core body temperature to drop markedly in mice, increased intestinal epithelial barrier permeability and facilitated FA development. CS promoted interleukin (IL)-33 expression in intestinal epithelial cells through the adrenocorticotropic hormone (ACTH)/cortisol axis and via inducing the Il33 promoter methylation. CS facilitated the FA development in mice, that could be blocked by depletion of IL-33 expression in intestinal epithelial cells. CONCLUSIONS: CS induces IL-33 expression in intestinal epithelial cells to promote Th2 polarization in the intestinal tissues and facilitates FA development.

Molecular and functional analyses of novel anti-lipopolysaccharide factors in giant river prawn (Macrobrachium rosenbergii, De Man) and their expression responses under pathogen and temperature exposure.

Anti-lipopolysaccharide factor (ALF) is an immune-related protein that is crucially involved in immune defense mechanisms against invading pathogens in crustaceans. In the current study, three different ALFs of giant river prawn (Mr-ALF3, Mr-ALF8 and Mr-ALF9) were discovered. Based on sequence analysis, Mr-ALF3 and Mr-ALF9 were identified as new members of ALFs in crustaceans (groups F and G, respectively). Structurally, each newly identified Mr-ALF contained three α-helices packed against a four-stranded ß-sheet bearing the LPS-binding motif, which usually binds to the cell wall components of bacteria. Tissue expression analysis using quantitative real-time RT-PCR (qRT-PCR) demonstrated that Mr-ALF3 was expressed in most tissues, and the highest expression was in the heart and hemocytes. The Mr-ALF8 gene was highly expressed in the heart, hemocytes, midgut, hepatopacreas and hindgut, respectively, while the Mr-ALF9 gene was modestly expressed in the heart and hemocytes, respectively. The transcriptional responses of the Mr-ALFs to Aeromonas hydrophila and hot/cold temperatures were investigated by qRT-PCR in the gills, hepatopancreas and hemocytes. We found that all Mr-ALFs were clearly suppressed in all tested tissues when the experimental prawns were exposed to extreme temperatures (25 and 35 °C). Moreover, the expression levels of these genes were significantly induced in all examined tissues by 2 different concentrations of A. hydrophila (1 × 106 and 1 × 109 CFU/ml), particularly 12 and 96 h after the injection. Finally, binding activity analysis of LPS-motif peptides of each Mr-ALF revealed that the LPS peptide of Mr-ALF3 exhibited the strongest adhesion to two pathogenic Gram-negative bacteria, A. hydrophila and Vibrio harveyi, and the non-pathogenic Gram-positive Bacillus megaterium. The results also showed that the Mr-ALF8 and Mr-ALF9 peptides had mild antimicrobial effects against similar tested bacteria. Based on information obtained in this study, novel ALF genes were clearly identified. Analyses of their responses under pathogenic and temperature stresses demonstrated the binding and antimicrobial activities of these ALFs and the consequent physiological effects, indicating their crucial functional roles in the prawn immune system.

An Adjuvant-Free Mouse Model of Transdermal Sensitization and Oral Elicitation of Anaphylaxis to Shellfish.

BACKGROUND: Shellfish (SF) allergy is a leading cause of systemic anaphylaxis in humans. An adjuvant-free mouse model to evaluate allergenicity and oral anaphylaxis to SF is currently unavailable. Here, we tested the hypothesis that transdermal exposure (TDE) to SF protein extract (SFPE) not only elicits a systemic allergic immune response but also will clinically sensitize mice for oral anaphylaxis. METHODS: Adult BALB/c female mice (6-8 weeks of age) were exposed to saline or SFPE once a week for 4 weeks using a transdermal sensitization method. Systemic SF-specific IgE, IgG1 and IgG2a and total (t)IgE responses were measured using ELISA. Systemic anaphylaxis upon oral SFPE administration was assessed according to clinical symptoms and the hypothermia shock response (HSR). Using individual mouse data, the correlation between the readouts of allergenicity was determined using Pearson's analysis. Spleen-cell IL-4 and IFN-x03B3; responses were determined using primary cell culture and ELISA. RESULTS: TDE to SFPE resulted in marked systemic specific (s)IgE, tIgE, IgG1 and IgG2a responses. Oral challenge with SFPE in sensitized mice (but not controls) elicited systemic anaphylactic clinical reactions and HSR. A strong correlation was observed between sIgE, tIgE and HSR. Spleen cells isolated from allergic mice (but not controls) exhibited memory IL-4 and IFN-x03B3; cytokine responses. CONCLUSION: We report a novel adjuvant-free mouse model of SF allergy with robust quantifiable and correlated readouts of allergenicity that may be used in basic biomedical, preclinical and applied food/nutrition research on SF allergy.

Mild cold-stress depresses immune responses: Implications for cancer models involving laboratory mice.

Physiologically accurate mouse models of cancer are critical in the pre-clinical development of novel cancer therapies. However, current standardized animal-housing temperatures elicit chronic cold-associated stress in mice, which is further increased in the presence of tumor. This cold-stress significantly impacts experimental outcomes. Data from our lab and others suggest standard housing fundamentally alters murine physiology, and this can produce altered immune baselines in tumor and other disease models. Researchers may thus underestimate the efficacy of therapies that are benefitted by immune responses. A potential mediator, norepinephrine, also underlies stress pathways common in mice and humans. Therefore, research into mechanisms connecting cold-stress and norepinephrine signaling with immune depression in mice could highlight new combination therapies for humans to simultaneously target stress while stimulating anti-tumor immunity.

Effects of cold stress on mRNA expression of immunoglobulin and cytokine in the small intestine of broilers.

To investigate the effects of cold stress on mRNA expression of immunoglobulin and cytokine in small intestine of broilers, eighty-four 15-day-old male chickens were randomly divided into 12 groups. There were 1 control (25°C) and 5 acute stress groups (under the temperature of 12 ± 1°C) for 1, 3, 6, 12 and 24h, 3 control (25°C) and 3 chronic cold stress groups (under the temperature of 12 ± 1°C) for 5, 10, and 20d. The mRNA expression levels of IL-2, IL-4, IL-7, IL-10, IL-17, IFN-γ, IgA, IgM, IgG, plgR, and TGF-ß4 in duodenum, jejunum and ileum were detected by real-time PCR. The results showed that expression levels of IgM, IgA, IgG, plgR and IL-7 had an increased tendency in acute and chronic cold stress, especially plgR that was markedly increased in the duodenum than jejunum and ileum in the acute cold stress. In addition, the mRNA expression levels of IL-2, IFN-γ, IL-4, IL-17 and TGF-ß4 had a first increased then decreased tendency in acute and chronic cold stress groups, however, expression levels of IL-4 were higher in the stress groups than control groups. The histopathological detect showed that issues in cold stress group was seriously injured. These results demonstrated that cold stress could cause the change of immune function in chicken intestinal.

Role of complement in a murine model of peanut-induced anaphylaxis.

Peanut allergy is severe and persisting from childhood to adulthood. However, there is no effective prophylaxis or treatment for peanut allergy. Little is known to about the molecular process in the pathogenesis of peanuts allergy, especially in innate immunity. Thus we investigated the role of complement activation in murine peanut anaphylaxis. Complement component C3 deposition on peanut extract (PE) was evaluated using sera from wild-type (WT), mannose-binding lectin associated serine protease (MASP)-1/3 deficient, MASP-2 deficient, and C4 deficient mice. Sera from interferon regulatory factor-4 (IRF-4) deficient mice, which lack serum immunoglobulin, were also used. In anaphylaxis study, mice were pretreated with propranolol and a long-acting form of IL-4, and injected with PE. Mice were then assessed for plasma C3a levels and hypothermia shock by ELISA and rectal temperature measurement, respectively. C3 deposition on PE was abolished in immunoglobulin- and C4-deficient sera. No difference in C3 deposition levels were observed among WT, MASP-1/3 deficient and MASP-2 deficient sera. IgM, IgG2b, IgG3, C1q, and ficolin-A deposits were detected on PE. In anaphylaxis study, MASP-1/3 deficient mice showed elevation of plasma C3a levels similar to WT mice. However, they were significantly reduced in C4- and MASP-2-deficient mice compared to WT mice. Consistently, PE-induced anaphylactic shock was prevented in C4 deficient mice and partially in MASP-2 deficient mice. In conclusion, PE activates complement via both the lectin and classical pathways in vivo, and the complement activation contributes to hypothermia shock in mice.

Cold stress induced morphological microglial activation and increased IL-1ß expression in astroglial cells in rat brain.

The present study investigated the possible impact of cold stress on the immune functions of the brain. Wistar rats were exposed to 4°C for 2h prior to analysis of immunohistochemical analysis of OX-42 and IL-1ß, which are markers of microglia and inflammation, respectively. Exposure to cold stress induced morphological microglial activation in as early as 30 min, and the activation lasted up to 2h following the stress. In addition, increased IL-1ß-immunoreactivity was detected in the hippocampus and hypothalamus. However, IL-1ß was not co-localized with microglia, and was predominantly expressed in astroglia. The present study provides the first evidence that cold stress contributes to neuro-immunomodulation in the brain through microglial activation and expression of IL-1ß in astroglia.