Selenoproteins and heat shock proteins play important roles in immunosuppression in the bursa of Fabricius of chickens with selenium deficiency

Selenium prevented renal tissue damage in lipopolysaccharide-treated rats

OBJECTIVES

Kidney diseases are one of the common diseases, which are one of the main causes of death in society and impose costs on the health system of the society. A growing body of evidence has well documented that inflammatory responses and oxidative damage play a significant role in the progress of various kidney diseases.

METHODS

This study examined whether selenium (Sel) could prevent the detrimental influences of lipopolysaccharide (LPS) in rats. Four groups of Wistar rats were considered: control, LPS (1 mg/kg, i.p., for 14 days), LPS-Sel 1 (0.1 mg/kg, i.p., for 14 days), and LPS-Sel 2 (0.2 mg/kg, i.p., for 14 days).

RESULTS

Sel treatment markedly attenuated oxidative stress damage in the kidney tissue in LPS-induced renal toxicity. Generally, the administration of Sel resulted in improved antioxidant indicators such as catalase (CAT) and superoxide dismutase (SOD) activities, or total thiol content, and decreased malondialdehyde (MDA) in the kidney tissue. It also decreased interleukin-6 in kidney homogenates. Furthermore, Se treatment significantly inhibited the elevation of serum biochemical markers of kidney function including serum, BUN, and creatinine.

CONCLUSIONS

Based on the findings of the current study, it seems that the administration of Sel to LPS-treated rats improves renal function by reducing oxidative damage and inflammation in kidney tissue. However, more research is needed to reveal the accurate mechanisms for the effect of Sel on renal outcomes of LPS in human subjects.

Prognostic value and immunological roles of GPX3 in gastric cancer

Objective: The prognosis for gastric cancer (GC), a prevalent tumor of the digestive system, is unfavorable. The involvement of glutathione peroxidase 3 (GPX3) in tumorigenesis is significant, yet its specific role in GC remains insufficiently investigated. Thus, the aim of this study was to determine the potential impact of GPX3 on GC and elucidate the underlying mechanism. Methods: The expression and survival of GPX3 in GC were analyzed using TCGA data. Additionally, the GPX3 mRNA and protein levels in GC were also assessed using datasets from GTEx, GEPIA, and HPA. A total of 38 pairs of GC tissues, along with their adjacent normal tissues, were collected from the Tianjin Medical University General Hospital, accompanied by detailed clinical information. The expression levels of GPX3 were subsequently determined for the purpose of validation. Following expression, correlation, and survival analyses, we proceeded to investigate the upstream non-coding RNA (ncRNA) of GPX3 using starBase and miRNet. Additionally, the co-expression networks of GPX3 were examined based on LinkedOmics. Lastly, we explored the correlation between GPX3 and immune cell infiltration, as well as the biomarkers of immune cells and immune checkpoints in GC. Furthermore, the GDSC database offered valuable drug sensitivity information. Results: A lower expression of GPX3 was observed in individuals with GC, while a higher expression of GPX3 was associated with a poorer prognosis. The DUBR/hsa-miR-502-3p/GPX3 pathway was identified as the most promising upstream ncRNA pathway related to GPX3 in GC. GO and KEGG enrichment analysis revealed that GPX3 expression was linked to coagulation cascades and cell locomotion. Furthermore, GPX3 levels in GC were positively correlated with immune cell infiltration, immune cell biomarkers, and immune checkpoint expression. The group with low GPX3 expression also exhibited increased sensitivity to 5-fluorouracil, doxorubicin, and other drugs. Conclusions: Collectively, we hypothesized that the potential involvement of non-coding RNAs in the downregulation of GPX3 could contribute to the inhibition of tumor formation during the malignant transition from gastritis to GC. Nevertheless, it was plausible that GPX3 may also facilitate tumor progression to advanced stages by promoting immune cell infiltration and activating immune checkpoints.

Ferroptosis-mediated immune responses in cancer

Cell death is a universal biological process in almost every physiological and pathological condition, including development, degeneration, inflammation, and cancer. In addition to apoptosis, increasing numbers of cell death types have been discovered in recent years. The biological significance of cell death has long been a subject of interest and exploration and meaningful discoveries continue to be made. Ferroptosis is a newfound form of programmed cell death and has been implicated intensively in various pathological conditions and cancer therapy. A few studies show that ferroptosis has the direct capacity to kill cancer cells and has a potential antitumor effect. As the rising role of immune cells function in the tumor microenvironment (TME), ferroptosis may have additional impact on the immune cells, though this remains unclear. In this study we focus on the ferroptosis molecular network and the ferroptosis-mediated immune response, mainly in the TME, and put forward novel insights and directions for cancer research in the near future.

The role of selenoprotein M in nickel-induced pyroptosis in mice spleen tissue via oxidative stress

Nickel (Ni) is a heavy metal element and a pollutant that threatens the organism's health. Melatonin (Mel) is an antioxidant substance that can be secreted by the organism and has a protective effect against heavy metals. Selenoprotein M (SelM) is a selenoprotein widely distributed of the body, and its role is to protect these tissues from oxidative damage. To study the mechanism of Ni, Mel, and SelM in mouse spleen, 80 SelM^+/+ wild-type and 80 SelM^-/- homozygous mice were divided into 8 groups with 20 mice in each group. The Ni group was intragastric at a concentration of 10 mg/kg, while the Mel group was intragastric at 2 mg/kg. Mice were injected with 0.1 mL/10 g body weight for 21 days. Histopathological and ultrastructural observations showed the changes in Ni, such as the destruction of white and red pulp and the appearance of pyroptosomes. SelM knockout showed more severe injury, while Mel could effectively interfere with Ni-induced spleen toxicity. The results of antioxidant capacity determination showed that Ni could cause oxidative stress in the spleen, and Mel could also effectively reduce oxidative stress. Finally, Ni exposure increased the expression levels of the pyroptotic genes, including apoptosis-associated speck protein (ASC), absent in melanoma-2 (AIM2), NOD-like receptor thermal protein domain-associated protein 3 (NLRP3), Caspase-1, interleukin- (IL-) 18, and IL-1β (p < 0.05). Loss of SelM significantly increased these (p < 0.05), while Mel decreased the alleviated impact of Ni. In conclusion, the loss of SelM aggravated Ni-induced pyroptosis of the spleen via activating oxidative stress, which was alleviated by Mel, but the effect of Mel was not obvious in the absence of SelM, which reflected the important role of SelM in Ni-induced pyroptosis.

Metabolomic Analysis Reveals the Adaptation in the P. przewalskii to Se-Deprived Environment

The Procapra przewalskii inhabits in a selenium (Se)-deprived environment in long-term, but they have no pathological manifestations due to the Se deprivation. This study aimed to reveal the underlying adaptation induced by Se deprivation. In the analysis, a total of 93 significantly changed metabolites were identified in positive and negative ion modes, including 46 upregulated and 47 downregulated compounds in the Se-deprived group. The differential metabolites were annotated as the major molecules in bile acid biosynthesis, biosynthesis of unsaturated fatty acids, and pyrimidine metabolism, respectively. This study systematically analyzed the serum metabolomics characteristics of P. przewalskii under Se-deprived conditions for the first time, providing a basis for further understanding of the metabolic mechanism of P. przewalskii in the Se-deprived environment.

Antioxidant stress and anticancer activity of peptide‑chelated selenium in vitro

The association between selenium and peptide in gastric cancer is an important research topic. The present study reported the facile synthesis of anticancer bioactive peptide (ACBP)-functionalized selenium (ACBP-S-Se) particles with enhanced anticancer activities and a detailed mechanistic evaluation of their ability to regulate oxidative stress in vitro. Structural and chemical characterizations were revealed by ultraviolet absorption, Fourier transform infrared, X-ray photoelectron, nuclear magnetic resonance carbon and hydrogen, energy dispersive X-ray spectroscopy and inductively coupled plasma mass spectrometry, as well as scanning electron microscopy. Sulfhydrylation modifications of ACBP were achieved with Sacetylmercaptosuccinic anhydride via chemical absorption. After the polypeptide was modified by sulfhydrylation, the ACBP chain was linked to sulfhydryl groups by amide bonds to form the ACBP-chelated selenium complex. Two gastric cancer cell lines (MKN-45 and MKN-74 cells) demonstrated high susceptibility to ACBP-S-Se particles and displayed significantly decreased proliferation ability following treatment. The results suggested that the bioactive peptide-chelated selenium particles effectively inhibited the proliferation of MKN-45 and MKN-74 cells in vitro. The genes encoding CDK inhibitor 1A (CDKN1A), cyclin B1, thioredoxin (TXN) and mitogen-activated protein kinase kinase kinase 5 are associated with regulation of oxidative stress, while CDKN1A and TXN protect cells by decreasing oxidative stress and promoting cell growth arrest. Therefore, ACBP-S-Se may be an ideal chemotherapeutic candidate for human cancer, especially gastric cancer.

Nephropathogenic Infectious Bronchitis Virus Infection Altered the Metabolome Profile and Immune Function of the Bursa of Fabricius in Chicken

Infectious bronchitis is a highly contagious, acute viral respiratory disease of chickens, regardless of the strain, and its infection may lead to considerable economic losses to the poultry industry. New nephropathogenic infectious bronchitis virus (NIBV) strains have increasingly emerged in recent years; hence, evaluating their infection-influenced immune function changes and the alteration of metabolite profiling is important. Initially, chickens were randomly distributed into two groups: the control group (Con) and the disease group (Dis). Here, the partial cytokines were examined, and the metabolome alterations of the bursa of Fabricius (BF) in NIBV infections in chickens were profiled by gas chromatography time-of-flight/mass spectrometry (GC-TOF/MS). The results revealed that the NIBV infection promotes the mRNA expression of inflammatory cytokines. Metabolic profile analysis indicated that clustering differed between the two groups and there were 75 significantly different metabolites detected between the two groups, suggesting that the host metabolism was significantly changed by NIBV infection. Notably, the following 12 metabolites were identified as the potential biomarkers: 3-phenyllactic acid, 2-deoxytetronic acid, aminomalonic acid, malonamide 5, uric acid, arachidonic acid, 2-methylglutaric acid, linoleic acid, ethanolamine, stearic acid, N-alpha-acetyl-l-ornithine, and O-acetylserine. Furthermore, the results of the correlation analysis showed that a strong correlation existed between metabolic biomarkers and inflammatory cytokines. Our results describe an immune and metabolic profile for the BF of chickens when infected with NIBV and provide new biomarkers of NIBV infection as potential targets and indicators of indicating therapeutic efficacy.

MiR-1696/GPx3 axis is involved in oxidative stress mediated neutrophil extracellular traps inhibition in chicken neutrophils

As an important immune mechanism of neutrophils, the release of Web-like chromatin structures known as neutrophil extracellular traps (NETs) can rapidly locate and capture invading pathogens, which has received sustained attention. There are still some fundamental questions surrounding established studies on the mechanism of balance between reactive oxygen species (ROS) dependent release and neutrophil antioxidant response. Glutathione peroxidase 3 (GPx3) is an important antioxidant protein and has been identified can regulate the immune response. However, the effect of GPx3 on the NETs formation and microRNA in this process remain poorly understood. In the present study, we used chicken peripheral blood neutrophils treated with Phorbol-12-myristate-13-acetate (PMA) for 3 h as NETs formation model. The result of morphological observation showed that GPx3 inactivation compromised the release of NETs. Further analysis revealed that knockdown of GPx3 significantly disturbed oxidative balance by inhibiting antioxidant enzymes activity and increasing H₂ O₂ content. Quantitative analysis of NETs-related genes found that the phosphorylation level of mitogen-activated protein kinase (MAPK) pathway genes (ERK, JNK, and p38) and expression of phosphoinositide-3-kinase (PI3K)/AKT pathway genes (PI3K and AKT) were suppressed with the downregulation of GPx3. Meanwhile, we identified that miR-1696 can target GPx3 expression by using dual luciferase reporter system. Additionally, overexpression of miR-1696 can not only inhibit the formation of NETs by restraining the expression of GPx3, interfering with the generation of ROS and activation of the MAPK and PI3K/AKT pathways, but also reducing the release of PMA-induced NETs promoted by overexpression of GPx3. These results provide evidence that miR-1696 targeted GPx3 activities in neutrophils could be used to regulate the NETs formation stimulated by PMA.

Transcriptomic Analysis of Spleen Revealed Mechanism of Dexamethasone-Induced Immune Suppression in Chicks

Stress-induced immunosuppression is a common problem in the poultry industry, but the specific mechanism of its effect on the immune function of chicken has not been clarified. In this study, 7-day-old Gushi cocks were selected as subjects, and a stress-induced immunosuppression model was successfully established via daily injection of 2.0 mg/kg (body weight) dexamethasone. We characterized the spleen transcriptome in the control (B_S) and model (D_S) groups, and 515 significant differentially expressed genes (SDEGs) (Fragments Per Kilobase of transcript sequence per Millions base pairs sequenced (FPKM) > 1, adjusted p-value (padj) < 0.05 and Fold change (|FC|) ≥ 2) were identified. The cytokine-cytokine receptor interaction signaling pathway was identified as being highly activated during stress-induced immunosuppression, including the following SDEGs-CXCL13L2, CSF3R, CSF2RB, CCR9, CCR10, IL1R1, IL8L1, IL8L2, GHR, KIT, OSMR, TNFRSF13B, TNFSF13B, and TGFBR2L. At the same time, immune-related SDEGs including CCR9, CCR10, DMB1, TNFRSF13B, TNFRSF13C and TNFSF13B were significantly enriched in the intestinal immune network for the IgA production signaling pathway. The SDEG protein-protein interaction module analysis showed that CXCR5, CCR8L, CCR9, CCR10, IL8L2, IL8L1, TNFSF13B, TNFRSF13B and TNFRSF13C may play an important role in stress-induced immunosuppression. These findings provide a background for further research on stress-induced immunosuppression. Thus, we can better understand the molecular genetic mechanism of chicken stress-induced immunosuppression.

Selenomethionine relieves inflammation in the chicken trachea caused by LPS though inhibiting the NF-κB pathway

Selenomethionine is able to relieve the effect of inflammation in various tissues and organs. However, there are few studies about the influences of organic selenium resisting inflammation induced by LPS in chicken trachea. Therefore, the purpose of this experiment is to explore the organic selenium (selenomethionine) can raise immune function and relieve the LPS-induced inflammation of chicken trachea via inhibiting the NF-κB pathway. To investigate the mechanism of organic selenium on chicken trachea, the supplement of selenomethionine and/or LPS-induced chicken models were established. One hundred 46-week-old isa chickens were randomly divided into four groups (n = 25). The four groups were the control group, the selenomethionine group (Se group), the LPS-induced group (LPS group), and the Se and LPS interaction group (Se + LPS group). Then, the expressions of inflammatory factors (including induced nitric oxide synthase (iNOS), nuclear factor-kappa B(NF-κB), tumor necrosis factor (TNF-α), cyclooxygenase-2 (COX-2), and prostaglandin E (PTGEs) synthase), inflammation-related cytokines (including interleukin (IL-2, IL-6, IL-8, IL-17) and immunoglobulin (IgA, IgM, IgY)), the marker of immune function (avian β-defensins (AvBD6, AvBD7)), heat shock proteins (including HSP60, HSP90), and selenoproteins (including Selo, Sels, Selm, Selh, Selu, Seli, SPS2, GPx1, GPx2, Dio1, Sepx1, Sep15, Sepp1, Txnrd1) were detected in our experiment. The above genes were significantly changed in different groups (p < 0.05). We can conclude that organic selenium can increase the function of immunity and the expression of selenoproteins, and mitigate the inflammation induced by LPS via suppression of the NF-κB pathway.

Selenium deficiency inhibits differentiation and immune function and imbalances the Th1/Th2 of dendritic cells

Selenium (Se) deficiency inhibits immune cell differentiation, affects immune response, and leads to cellular and humoral immune dysfunction. However, the impact of Se deficiency on the differentiation and Th1/Th2 balance of dendritic cells is still unclear. In this study, we replicated a model of Se-deficient chickens by feeding the chickens with a low-Se diet (i.e., the content of Se is 0.008 mg per kg diet). On this basis, we explored the effect of Se deficiency on the differentiation of chicken dendritic cells by induction culture of peripheral blood monocyte cells. We induced chicken dendritic cells by incubating mononuclear cells with a 100 ng mL-1 recombinant chicken granulocyte-macrophage colony-stimulating factor and 20 ng mL-1 recombinant chicken IL-4 for total 7 days. The results showed that Se deficiency decreased the expression of cell-surface markers including CD11c, CD40, CD86, and MHC II. Furthermore, we analyzed the cytokine profiles using real-time quantitative PCR and ELISA. The results indicated that Se deficiency inhibited the expression of selenoproteins and changed the secretion of IL-10, IL-12p40, and IFN-γ. Additionally, Se deficiency weakened the ability of dendritic cells to stimulate the proliferation of mixed allogeneic lymphocytes. In conclusion, Se deficiency suppressed the differentiation and immune function of chicken dendritic cells by down-regulating the expression of CD11c, CD40, CD86, MHC II, and selenoproteins. The result also showed that the Th1/Th2 imbalance was induced by enhancing the secretion of Th1-type cytokine IL-12p40 and IFN-γ and reducing that of Th2-type cytokine IL-10. Our findings contribute to understanding the mechanism of Se deficiency in the differentiation and immune function of chicken dendritic cells.

Dietary selenium supplementation alleviates immune toxicity in the hearts of chickens with lead-added drinking water

Lead (Pb) is an environmental pollutant and can damage organisms. Selenium (Se) can alleviate Pb poisoning. The present study aimed to investigate the alleviative effect of Se on Pb-induced immune toxicity in chicken hearts. One-hundred-and-eighty Hy-line male chickens were randomly divided into four groups at 7 days of age. The control group was offered a standard commercial diet (SD) and drinking water (DW); the Se group was offered SD supplemented with sodium selenite (SeSD) and DW; the Pb + Se group was offered SeSD and DW supplemented with lead acetate (PbDW); and the Pb group was offered SD and PbDW. Relative mRNA expression of inducible nitric oxide synthase (iNOS), interleukins (IL-2, IL-4, IL-6, IL-12β, IL-17 and IFN-γ), and heat shock proteins (HSP27, HSP40, HSP60, HSP70, and HSP90) were determined by means of quantitative real-time PCR. Relative protein expression of iNOS, HSP60, HSP70, and HSP90 was assessed, as well as nitric oxide (NO) content and iNOS activity in heart tissue. The results indicated a down-regulation of interleukin (IL)-2 and IFN-γ and an up-regulation of NO, iNOS, interleukins (IL-4, IL-6, IL-12β, IL-17), and heat shock proteins (HSP27, HSP40, HSP60, HSP70, and HSP90) in Pb-damaged hearts. Se alleviated all of the above Pb-induced changes. There were time-dependent effects on NO content, iNOS activity, and mRNA levels of iNOS, IL-2, IL-4, IL-6, IL-17, HSP27, HSP40, HSP60, HSP70, and HSP90 after Pb treatment in the chicken hearts. Se alleviated Pb-induced immune toxicity in the chicken hearts.

The effects of atmospheric hydrogen sulfide on peripheral blood lymphocytes of chickens: Perspectives on inflammation, oxidative stress and energy metabolism

Excessive hydrogen sulfide (H₂S) affects poultry health. Exposure to air pollution induces inflammation, oxidative stress, energy metabolism dysfunction and adverse health effects. However, few detailed studies have been conducted on the molecular mechanisms of H₂S-induced injury in poultry. To understand how H₂S drives its adverse effects on chickens, twenty-four 14-day-old chickens were randomly divided into two groups. The chickens in the control group were raised in a separate chamber without H₂S, and the chickens in the treatment group were exposed to 30 ppm H₂S. After 14 days of exposure, peripheral blood samples were taken and the lymphocytes were extracted to detect inflammation, oxidative stress and energy metabolism in broilers. Overall, an increase in the inflammatory response was detected in the peripheral blood lymphocytes following H₂S exposure compared to the control group, and the expression levels of the heat shock proteins (HSPs) and the transcription factors nuclear factor κB (NF-κB), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) were up-regulated in the H₂S group, which further suggested that H₂S induced an inflammatory response via the NF-κB pathway. Because of the activation of NF-κB, which is a major regulator of oxidative stress, we also observed that reactive oxygen species (ROS) production was elevated under H₂S exposure. In addition, we presumed that energy metabolism might be damaged due to the increased ROS production, and we found that H₂S down-regulated the expression levels of energy metabolism-related genes, which indicated the occurrence of energy metabolism dysfunction. Altogether, this study suggests that exposure to excessive atmospheric H₂S induces an inflammatory response, oxidative stress and energy metabolism dysfunction, providing a reference for comparative medicine.

Selenium-Dependent Antioxidant Enzymes: Actions and Properties of Selenoproteins

Unlike other essential trace elements that interact with proteins in the form of cofactors, selenium (Se) becomes co-translationally incorporated into the polypeptide chain as part of 21st naturally occurring amino acid, selenocysteine (Sec), encoded by the UGA codon. Any protein that includes Sec in its polypeptide chain is defined as selenoprotein. Members of the selenoproteins family exert various functions and their synthesis depends on specific cofactors and on dietary Se. The Se intake in productive animals such as chickens affect nutrient utilization, production performances, antioxidative status and responses of the immune system. Although several functions of selenoproteins are unknown, many disorders are related to alterations in selenoprotein expression or activity. Selenium insufficiency and polymorphisms or mutations in selenoproteins' genes and synthesis cofactors are involved in the pathophysiology of many diseases, including cardiovascular disorders, immune dysfunctions, cancer, muscle and bone disorders, endocrine functions and neurological disorders. Finally, heavy metal poisoning decreases mRNA levels of selenoproteins and increases mRNA levels of inflammatory factors, underlying the antagonistic effect of Se. This review is an update on Se dependent antioxidant enzymes, presenting the current state of the art and is focusing on results obtained mainly in chicken.

Effect of Low-Selenium/High-Fat Diet on Pig Peripheral Blood Lymphocytes: Perspectives from Selenoproteins, Heat Shock Proteins, and Cytokines

The aim of the present study was to clarify the effect of low selenium (Se)/high fat on the mRNA expression of selenoproteins, heat shock proteins (HSPs) and cytokines in pig peripheral blood lymphocytes. Forty crossbred boar piglets with healthy lean body weights of 10 kg were randomly divided into four treatment groups (group C, group L-Se, group H-fat, and group L-Se-H-fat) (n = 10/group) and fed with the corresponding diet for 16 weeks. The pig peripheral blood lymphocytes were extracted, and the mRNA expression of selenoproteins, HSPs, and cytokines was measured. Most mRNA levels for selenoproteins decreased in group L-Se, group H-fat, and group L-Se-H-fat, except Gpx1, Gpx2, Selt, and Selm, which were elevated in group H-fat. At the same time, low-Se/high-fat diet increased the expression of HSPs (HSP40, HSP60, HSP70, and HSP90) and inflammatory cytokines (IL-1α, IL-1β, IL-6, IL-8, IL-9, iNOS, COX-2, NF-κB, and TNF-α) in group L-Se, group H-fat, and group L-Se-H-fat, and genes in group L-Se-H-fat showed greater increases. Also, low-Se/high-fat diet inhibits the expression of TGF-β1 and IFN-γ. In summary, a low-Se/high-fat diet can cause relevant selenoprotein expression changes and promote the expression of pro-inflammatory factors and HSPs, and low Se enhances the expression of HSPs and inflammation factors induced by high fat. This information is helpful for understanding the effects of low-Se and high-fat diet on pig peripheral blood lymphocytes.

Selenium Deficiency Augments the Levels of Inflammatory Factors and Heat Shock Proteins via the Redox Regulatory Pathway in the Skeletal Muscles of Mice

Dietary selenium (Se) deficiency is known to cause myodynia syndrome and Se influences immune responses by changing the expression of inflammatory cytokines and heat shock proteins (Hsps), but the details are not completely elucidated. In the present study, 72 1-day-old mice were divided into two groups; the first group was fed a Se-sufficient diet, while the second group was fed a Se-deficient diet. Skeletal muscles and blood samples were taken from all mice after 42 days of treatment. The activities of glutathione peroxidase (GPX) and glutathione (GSH), mRNA and protein expression levels of inflammatory cytokines (including TNF-α, inducible NO synthase, cyclooxygenase-2, and prostaglandin E synthases), protein expression levels of NF-κB, and the mRNA expression levels of Hsps in the skeletal muscles of mice were examined. The results showed that GPX and GSH activities were decreased, while the mRNA and protein expression levels of inflammatory cytokines and the mRNA levels of Hsps were increased by Se deficiency in mouse skeletal muscles. In the present study, the protective role of Se in oxidative stress, inflammatory cytokines, and Hsps in the skeletal muscles of mice was summarized.

Dextran sulphate sodium (DSS) causes intestinal histopathology and inflammatory changes consistent with increased gut leakiness in chickens

1. The clinical severity, histological changes, indicators of gut leakiness and inflammatory cytokine profiles were studied in chickens with dextran sulphate sodium (DSS)-induced intestinal inflammation. 2. The experimental groups (1.25%, 1.5% and 2.5% DSS) showed clinical signs, such as loose stools and weight loss, which increased with additional treatment days and, as expected, the effects of DSS-induced intestinal inflammation were time and dose-dependent. 3. After 10 d, histological manifestations were evident, including goblet cell depletion, mucus layer loss, significantly shorter villi and a thinner total ileal mucosa. 4. The d(-)-lactate value, which was used as a gut leakiness indicator, was significantly increased in the 2.5% DSS group. 5. Expression of the inflammatory cytokines interleukin-1Beta, tumour necrosis factor alpha and interleukin-10 in the serum significantly increased with DSS treatment. 6. This study indicates that the experimental intestinal inflammation induced by DSS is an ideal model to study the pathogenic mechanisms of intestinal inflammation in chickens and to test the efficacy of therapies.

Selenium accelerates chicken dendritic cells differentiation and affects selenoproteins expression

Selenium (Se) promotes immune cell differentiation and improves immune response. Antigen-presenting cells such as dendritic cells (DCs) play an important role in immune system, however, the impact of Se on DCs is still unclear. In this study, we successfully induced and cultured chicken DCs from peripheral blood mononuclear cells by incubating mononuclear cells with 50 ng/mL recombinant chicken granulocyte-macrophage colony stimulating factor and 10 ng/mL recombinant chicken interleukin-4 for total 9 days. In + Se group, we added 10^-7 mol/L sodium selenite from the first day of cell culture. The results showed that Se supplementation expedited and increased the expression of cell surface markers including CD11c, CD40, CD86, and MHC II. Principal component analysis showed that the expression of selenoproteins SelW, SelK, Dio3, GPX1, GPX2, SelN, SelS, SelH in chicken DCs was highly correlated, and SelW had highest correlation with the cell surface markers MHC II and CD11c. In conclusion, Se accelerates the differentiation and maturation of chicken DCs. Se regulates the differentiation and maturation of chicken DCs by selenoproteins. Selenoproteins has closely correlated to surface markers of chicken DCs.

Transcriptome profiling reveals the immune response of goose T cells under selenium stimuli

The goose is an economically important poultry species and a principal natural host of avian viruses. This study aimed to determine the effects of selenium on the immune response of geese. Under selenium stimulation, gene expression profiling was investigated using transcriptome sequencing. The selenoproteins were promoted by selenium stimulation, while the heat shock proteins, interleukin and interferons were mainly down-regulated. After comparison, 2228 differentially expressed genes were primarily involved in immune and environmental response, and infectious disease and genetic information processing related pathways were identified. Specifically, the enzymes of the lysosomes which acted as a safeguard in preventing pathogens were mostly up-regulated and six randomly selected differentially expressed genes were validated by quantitative polymerase chain reaction. In addition, the most proportional increased transcription factor family basic helix-loop-helix (bHLH) located in the 5' flank of selenoprotein P-like protein for selenium metabolism was identified by response to the selenium stimulation in this study. These analyses show that selenium can promote immune function by activating selenoproteins, transcript factors and lysosome pathway related genes, while weakening cytokine content genes in geese.

Selenium Deficiency Induces Autophagy in Immune Organs of Chickens

The aim of the present study was to investigate the effects of selenium (Se) deficiency on autophagy-related genes and on ultrastructural changes in the spleen, bursa of Fabricius, and thymus of chickens. The Se deficiency group was fed a basal diet containing Se at 0.033 mg/kg and the control group was fed the same basal diet containing Se at 0.15 mg/kg. The messenger RNA (mRNA) levels of the autophagy genes microtubule-associated protein 1 light chain 3 (LC3)-I, LC3-II, Beclin 1, dynein, autophagy associated gene 5 (ATG5), and target of rapamycin complex 1 (TORC1) were assessed using real-time qPCR. The protein levels of LC3-II, Beclin 1, and dynein were investigated using western blot analysis. Furthermore, the ultrastructure was observed using an electron microscope. The results indicated that spleen mRNA levels of LC3-I, LC3-II, Beclin 1, dynein, ATG5, and TORC1 and the protein levels of LC3-II, Beclin 1, and dynein were increased in the Se deficiency group compared with the control group. In the bursa of Fabricius, the mRNA levels of LC3-I, LC3-II, Beclin 1, dynein, ATG5, and TORC1 and the protein levels of Beclin 1 and dynein were increased; furthermore, the protein level of LC3-II was decreased in the Se deficiency group compared to the control group. In the thymus, the mRNA levels of LC3-I, Beclin 1, and ATG5 increased; the levels of LC3-II, dynein, and TORC1 were decreased; the protein level of Beclin 1 increased; and the levels of LC3-II and dynein decreased in the Se deficiency group compared to those in the control group. Further cellular morphological changes, such as autophagy vacuoles, autolysosomes, and lysosomal degradation, were observed in the spleen, bursa of Fabricius, and thymus of the Se-deficiency group. In summary, Se deficiency caused changes in autophagy-related genes, which increased the autophagic process and also caused structural damages to the immune organs of chickens.

Selenium Deficiency Activates Heat Shock Protein Expression in Chicken Spleen and Thymus

Heat shock proteins (Hsps) are protective proteins present in nearly all species; they are used as biomarkers of various stress conditions in humans, animals, and birds. Selenium (Se) deficiency, which can depress the production of Hsps, can cause chicken tissue injuries. To investigate Hsp production, mRNA, and protein levels in Se-deficient chicken spleens and thymuses, a total of 180 1-day-old sea blue white laying hens (90 chickens/group) were harvested in two groups (the control group and the Se-deficient group) in 15, 25, 35, 45, and 55 days, respectively. The results showed that mRNA levels of Hsp27, Hsp40, Hsp60, Hsp70, and Hsp90 were significantly increased in the spleens and thymuses of the Se-deficient group compared to the control group. Further protein levels of Hsp60, Hsp70, and Hsp90 were also significantly increased in the spleen and thymus of the Se-deficient group compared to the control group. Meanwhile, the spleen expression ratio of Hsp40 mRNA level and Hsp70 protein level were higher in the Se-deficient group than other proteins. In the thymus, the Hsp90 mRNA level and Hsp60 protein expression level were the highest level in the Se-deficient group among other proteins. Based on these results, we concluded that Se deficiency could induce a protective stress response in chicken by means of promoting the mRNA and protein expression of Hsps, thus easing the effects of Se deficiency to some extent.

Selenoprotein Transcript Level and Enzyme Activity as Biomarkers for Selenium Status and Selenium Requirements of Chickens (Gallus gallus)

The NRC selenium (Se) requirement for broiler chicks is 0.15 μg Se/g diet, based primarily on weight gain and feed intake studies reported in 1986. To determine Se requirements in today’s rapidly growing broiler chick, day-old male chicks were fed Se-deficient basal diets supplemented with graded levels of Se (0, 0.025, 0.05, 0.075, 0.1, 0.2, 0.3, 0.5, 0.75, and 1.0 μg Se/g) as Na₂SeO₃ (5/treatment). Diets contained 15X the vitamin E requirement, and there were no gross signs of Se-deficiency. At 29 d, Se-deficient chicks weighed 62% of Se-supplemented chicks; 0.025 μg Se/g reversed this effect, indicating a minimum Se requirement of 0.025 μg Se/g diet for growth for male broiler chicks. Enzyme activities in Se-deficient chicks for plasma GPX3, liver and gizzard GPX1, and liver and gizzard GPX4 decreased dramatically to 3, 2, 5, 10 and 5%, respectively, of Se-adequate levels, with minimum Se requirements of 0.10–0.13 μg Se/g, and with defined plateaus above these levels. Pancreas GPX1 and GPX4 activities, however, lacked defined plateaus, with breakpoints at 0.3 μg Se/g. qPCR measurement of all 24 chicken selenoprotein transcripts, plus SEPHS1, found that SEPP1 in liver, GPX3 in gizzard, and SEPP1, GPX3 and SELK in pancreas were expressed at levels comparable to housekeeping transcripts. Only 33%, 25% and 50% of selenoprotein transcripts were down-regulated significantly by Se deficiency in liver, gizzard and pancreas, respectively. No transcripts could be used as biomarkers for supernutritional Se status. For export selenoproteins SEPP1 and GPX3, tissue distribution, high expression and Se-regulation clearly indicate unique Se metabolism, which may underlie tissues targeted by Se deficiency. Based on enzyme activities in liver, gizzard, and plasma, the minimum Se requirement in today’s broiler chick is 0.15 μg Se/g diet; pancreas data indicate that the Se requirement should be raised to 0.2 μg Se/g diet to provide a margin of safety.