Roles of oxidative stress and endoplasmic reticulum stress in selenium deficiency-induced apoptosis in chicken liver

miR-200a-5p regulates myocardial necroptosis induced by Se deficiency via targeting RNF11

Necroptosis has been discovered as a new paradigm of cell death and may play a key role in heart disease and selenium (Se) deficiency. Hence, we detected the specific microRNA (miRNA) in response to Se-deficient heart using microRNAome analysis. For high-throughput sequencing using Se-deficient chicken cardiac tissue, we selected miR-200a-5p and its target gene ring finger protein 11 (RNF11) based on differential expression in cardiac tissue and confirmed the relationship between miR-200a-5p and RNF11 by dual luciferase reporter assay and real-time quantitative PCR (qRT-PCR) in cardiomyocytes. We further explored the function of miR-200a-5p and observed that overexpression of miR-200a-5p spark the receptor interacting serine/threonine kinase 3 (RIP3)-dependent necroptosis in vivo and in vitro. To understand whether miR-200a-5p and RNF11 are involved in the RIP3-dependent necroptosis pathway, we presumed that oxidative stress, inflammation response and the mitogen-activated protein kinase (MAPK) pathway might trigger necroptosis. Interestingly, necroptosis trigger, z-VAD-fmk, failed to induce necroptosis but enhanced cell survival against necrosis in cardiomyocytes with knockdown of miR-200a-5p. Our present study provides a new insight that the modulation of miR-200a-5p and its target gene might block necroptosis in the heart, revealing a novel myocardial necrosis regulation model in heart disease.

Regulation and function of avian selenogenome

BACKGROUND

Selenium (Se) is an essential micronutrient required by avian species. Dietary Se/vitamin E deficiency induces three classical diseases in chicks: exudative diathesis, nutritional pancreatic atrophy, and nutritional muscular dystrophy.

SCOPE OF REVIEW

This review is to summarize and analyze the evolution, regulation, and function of avian selenogenome and selenoproteome and their relationship with the three classical Se/vitamin E deficiency diseases.

MAJOR CONCLUSIONS

There are 24 selenoproteins confirmed in chicks, with two avian-specific members (SELENOU and SELENOP2) and two missing mammalian members (GPX6 and SELENOV). There are two forms of SELENOP containing 1 or 13 selenocysteine residues. In addition, a Gallus gallus gene was conjectured to be the counterpart of the human SEPHS2. Expression of selenoprotein genes in the liver, pancreas, and muscle of chicks seemed to be highly responsive to dietary Se changes. Pathogeneses of the Se/vitamin E deficient diseases in the chicks were likely produced by missing functions of selected selenoproteins in regulating cellular and tissue redox balance and inhibiting oxidative/reductive stress-induced cell death.

GENERAL SIGNIFICANCE

Gene knockout models, similar to those of rodents, will help characterize the precise functions of avian selenoproteins and their comparisons with those of mammalian species.

Lower Selenoprotein T Expression and Immune Response in the Immune Organs of Broilers with Exudative Diathesis Due to Selenium Deficiency

The objective of the present study was to investigate whether dietary selenium (Se) deficiency would affect the expression of selenoprotein T (SelT) and immune response in the immune organs of broilers. Changes in expression of inflammatory cytokines and oxidative stress response caused by Se deficiency can lead to organism damage, which in turn leads to immune response. Sixty (1-day-old) broilers were divided into the control group and Se-deficiency group. Animal models with exudative diathesis were duplicated in the broilers by feeding them Se-deficient diet for 20 days. After the Se-deficient group exhibited symptoms of exudative diathesis, all the broilers were euthanized, and their immune organs were taken for analysis. The tissues including spleen, bursa of Fabricius, and thymus were treated to determine the pathological changes (including microscopic and ultramicroscopic), the messenger RNA (mRNA) expression levels of SelT and its synthetase (SecS and SPS1), cytokine mRNA expression levels, and antioxidant status. The microscopic and ultramicroscopic analyses showed that immune tissues were obviously injured in the Se-deficient group. The mRNA expression of SelT was decreased compared with that in the control group. Meanwhile, the mRNA expression levels of SecS and SPS1 were downregulated. In the Se-deficient group, the mRNA expression levels of IL-1R and IL-1β were higher than those of three control organs. Additionally, the IL-2 and INF-γ mRNA expression levels were lower than those of the control group. The activity of CAT was decreased, and the contents of H₂O₂ and •OH were increased due to Se deficiency. Pearson method analysis showed that the expression of SelT had a positive correlation with IL-2, INF-γ, SecS, and SPS1 and a negative correlation with IL-1R and IL-1β. In summary, these data indicated that Se-deficient diet decreased the SelT expression and its regulation of oxidative stress, and it inhibited a pleiotropic mechanism of the immune response.

Porous Se@SiO2 nanocomposites protect the femoral head from methylprednisolone-induced osteonecrosis

Background

Methylprednisolone (MPS) is an important drug used in therapy of many diseases. However, osteonecrosis of the femoral head is a serious damage in the MPS treatment. Thus, it is imperative to develop new drugs to prevent the serious side effect of MPS.

Methods

The potential interferences Se@SiO₂ nanocomposites may have to the therapeutic effect of methylprednisolone (MPS) were evaluated by classical therapeutic effect index of acute respiratory distress syndrome (ARDS), such as wet-to-dry weight ratio, inflammatory factors IL-1β and TNF-α. And oxidative stress species (ROS) index like superoxide dismutase (SOD) and glutathione (GSH) were tested. Then, the protection effects of Se@SiO₂ have in osteonecrosis of the femoral head (ONFH) were evaluated by micro CT, histologic analysis and Western-blot analysis.

Results

In the present study, we found that in the rat model of ARDS, Se@SiO₂ nanocomposites induced SOD and GSH indirectly to reduce ROS damage. The wet-to-dry weight ratio of lung was significantly decreased after MPS treatment compared with the control group, whereas the Se@SiO₂ did not affect the reduced wet-to-dry weight ratio of MPS. Se@SiO₂ also did not impair the effect of MPS on the reduction of inflammatory factors IL-1β and TNF-α, and on the alleviation of structural destruction. Furthermore, micro CT and histologic analysis confirmed that Se@SiO₂ significantly alleviate MPS-induced destruction of femoral head. Moreover, compared with MPS group, Se@SiO₂ could increase collagen II and aggrecan, and reduce the IL-1β level in the cartilage of femoral head. In addition, the biosafety of Se@SiO₂ in vitro and in vivo were supported by cell proliferation assay and histologic analysis of main organs from rat models.

Conclusion

Se@SiO₂ nanocomposites have a protective effect in MPS-induced ONFH without influence on the therapeutic activity of MPS, suggesting the potential as effective drugs to avoid ONFH in MPS therapy.

Effects of both cold and heat stresses on the liver of giant spiny frog Quasipaa spinosa: stress response and histological changes

Ambient temperature associated stress can affect the normal physiological functions in ectotherms. To assess the effects of cold or heat stress on amphibians, the giant spiny frogs, Quasipaa spinosa, were acclimated at 22 °C followed by being treated at 5 °C or 30 °C for 0, 3, 6, 12, 24 and 48 h, respectively. Histological alterations, apoptotic index, mitochondrial reactive oxygen species (ROS) generation, antioxidant activity indices and stress-response gene expressions in frog livers were subsequently determined. Results showed that many fat droplets appeared after 12 h of heat stress. Percentage of melanomacrophages centres significantly changed during 48 h at both stress conditions. Furthermore, the mitochondrial ROS levels were elevated in a time-dependent manner up to 6 h and 12 h in the cold and heat stress groups, respectively. The activities of superoxide dismutase, glutathione peroxidase and catalase were successively increased along the cold or heat exposure, and most of their gene expression levels showed similar changes at both stress conditions. Most tested HSP genes were sensitive to temperature exposure, and the expression profiles of most apoptosis-related genes was significantly up-regulated at 3 and 48 h under cold and heat stress, respectively. Apoptotic index at 48 h under cold stress was significantly higher than that under heat stress. Notably, lipid droplets, HSP30, HSP70 and HSP110 might be suitable bioindicators of heat stress. The results of these alterations at physiological, biochemical and molecular levels might contribute to a better understanding of the stress response of Q. spinosa and even amphibians under thermal stresses.

Selenium antagonizes cadmium-induced apoptosis in chicken spleen but not involving Nrf2-regulated antioxidant response

The nuclear transcription factor NF-E2-related factor 2 (Nrf2) binds to antioxidant response elements (AREs) and is involved in the regulation of genes participated in defending cells against oxidative damage, which have been confirmed in animal models. Selenium (Se), known as an important element in the regulation of antioxidant activity, can antagonize Cadmium (Cd) toxicity in birds. However, the role of Nrf2 in selenium-cadmium interaction has not been reported in birds. To further explore the mechanism of selenium attenuating spleen toxicity induced by cadmium in chickens, cadmium chloride (CdCl₂, 150mg/kg) and sodium selenite (Na₂SeO₃, 2mg/kg) were co-administrated or individually administered in the diet of chickens for 90 days. The results showed that Cd exposure increased the level of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) and decreased the antioxidant enzyme activities, including superoxide dismutase (SOD), glutathione peroxidase (Gpx), total antioxidative capacity (T-AOC), catalase (CAT). Cd exposure increased obviously nuclear accumulation of Nrf2, and the expression of Nrf2 downstream heme oxygenase-1 (HO-1) and NAD(P)H: quinine oxidoreductase 1 (NQO1), reduced the expression of Kelch-like ECH-associated protein (keap1), Gpx-1 and thioredoxin reductase-1 (TrxR1). In addition, Cd induced the increase of bak, caspase9, p53, Cyt c mRNA levels, increased bax/bcl-2 ratio, increased caspase3 mRNA and protein levels. Selenium treatment reduced the accumulation of Cd in the spleen, attenuates Cd-induced Nrf2 nuclear accumulation, enhanced antioxidant enzyme activities, ameliorated Cd-induced oxidative stress and apoptosis in the spleen. In summary, our results demonstrate that Se ameliorated spleen toxicity induced by cadmium by modulating the antioxidant system, independently of Nrf2-regulated antioxidant response pathway.

Gene expression of selenoproteins can be regulated by thioredoxin(Txn) silence in chicken cardiomyocytes

Thioredoxin (Txn) system is the most crucial antioxidant defense mechanism in myocardium. The aim of this study was to clarify the effect of Txn low expression on 25 selenoproteins in chicken cardiomyocytes. We developed a Se-deficient model (0.033mg/kg) and Txn knock down cardiomyocytes model (siRNA) studies. Western Blot, Quantitative Real-time PCR (qPCR) were performed, and correlation analysis, heat map were used for further analysis. Both low expression of Txn models are significantly decreased (P<0.05) the mRNA levels of Deiodinase 1, 2 (Dio 1, 2), Glutathione Peroxidase 1, 2, 3, 4 (Gpx 1, 2, 3, 4), Thioredoxin Reductase 1, 2, 3 (TR 1, 2, 3), Selenoprotein t (Selt), Selenoprotein w (Selw), Selenoprotein k (Selk), selenoprotein x1 (Sepx1), and significantly increased (P<0.05) the mRNA levels of the rest of selenoproteins. Correlation analysis showed that Deiodinase 3 (Dio 3), Selenoprotein m (Selm), 15-kDa Selenoprotein (Selp15), Selenoprotein h (Selh), Selenoprotein u (Selu), Selenoprotein i (Seli), Selenoprotein n (Seln), Selenoprotein p1 (Sepp1), Selenoprotein o (Selo), Selenoprotein s (Sels), Selenoprotein synthetase 2 (Sels2) and Selenoprotein p (Selp) had a negative correlation with Txn, while the rest of selenoproteins had a positive correlation with Txn. Combined in vivo and in vitro we can know that hamper Txn expression can inhibit Gpx 1, 2, 3, 4, TR 1, 2, 3, Dio 1, 2, Selt, Selw, Selk, Sepx1, meanwhile, over expression the rest of selenoproteins. In conclusion, the different selenoproteins possess and exhibit distinct responses to silence of Txn in chicken cardiomyocytes.

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.

Down-regulation of microRNA-155 promotes selenium deficiency-induced apoptosis by tumor necrosis factor receptor superfamily member 1B in the broiler spleen

The aim of this work was to explore the microRNA profile and the effect of microRNA-155 on apoptosis in the spleen of selenium-deficient broilers. We replicated the splenic-apoptotic model in selenium-deficient broilers. In vitro, microRNA-155 oligonucleotides were transfected into lymphocytes and subsequently treated with H₂O₂. We observed that selenium deficiency altered the microRNA profile and decreased the expression of microRNA-155 in the broiler spleens. Tumor necrosis factor receptor superfamily member 1B was verified as a target of microRNA-155 in the splenocytes. Morphological changes, increased levels of tumor necrosis factor receptor superfamily member 1B, c-Jun N-terminal kinase, Bak, Bax, Cyt-c, caspase9 and caspase3 and decreased levels of Bcl-2 demonstrated that selenium deficiency induced apoptosis in the spleen tissues. In vitro, microRNA-155 m inhibited the levels of ROS and reduced apoptosis compared with microRNA-155i in the lymphocytes. These results suggested that the reduced levels of microRNA-155 due to selenium deficiency could promote oxidative stress-induced apoptosis by increased tumor necrosis factor receptor superfamily member 1B in splenic cells.

Comparative genomics of Clavibacter michiganensis subspecies, pathogens of important agricultural crops

Subspecies of Clavibacter michiganensis are important phytobacterial pathogens causing devastating diseases in several agricultural crops. The genome organizations of these pathogens are poorly understood. Here, the complete genomes of 5 subspecies (C. michiganensis subsp. michiganensis, Cmi; C. michiganensis subsp. sepedonicus, Cms; C. michiganensis subsp. nebraskensis, Cmn; C. michiganensis subsp. insidiosus, Cmi and C. michiganensis subsp. capsici, Cmc) were analyzed. This study assessed the taxonomic position of the subspecies based on 16S rRNA and genome-based DNA homology and concludes that there is ample evidence to elevate some of the subspecies to species-level. Comparative genomics analysis indicated distinct genomic features evident on the DNA structural atlases and annotation features. Based on orthologous gene analysis, about 2300 CDSs are shared across all the subspecies; and Cms showed the highest number of subspecies-specific CDS, most of which are mobile elements suggesting that Cms could be more prone to translocation of foreign genes. Cms and Cmi had the highest number of pseudogenes, an indication of potential degenerating genomes. The stress response factors that may be involved in cold/heat shock, detoxification, oxidative stress, osmoregulation, and carbon utilization are outlined. For example, the wco-cluster encoding for extracellular polysaccharide II is highly conserved while the sucrose-6-phosphate hydrolase that catalyzes the hydrolysis of sucrose-6-phosphate yielding glucose-6-phosphate and fructose is highly divergent. A unique second form of the enzyme is only present in Cmn NCPPB 2581. Also, twenty-eight plasmid-borne CDSs in the other subspecies were found to have homologues in the chromosomal genome of Cmn which is known not to carry plasmids. These CDSs include pathogenesis-related factors such as Endocellulases E1 and Beta-glucosidase. The results presented here provide an insight of the functional organization of the genomes of five core C. michiganensis subspecies, enabling a better understanding of these phytobacteria.

Treatment of steroid-induced osteonecrosis of the femoral head using porous Se@SiO2 nanocomposites to suppress reactive oxygen species

Reducing oxidative stress (ROS) have been demonstrated effective for steroid-induced osteonecrosis of the femoral head (steroid-induced ONFH). Selenium (Se) plays an important role in suppressing oxidative stress and has huge potential in ONFH treatments. However the Se has a narrow margin between beneficial and toxic effects which make it hard for therapy use in vivo. In order to make the deficiency up, a control release of Se (Se@SiO₂) were realized by nanotechnology modification. Porous Se@SiO₂ nanocomposites have favorable biocompatibility and can reduced the ROS damage effectively. In vitro, the cck-8 analysis, terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) stain and flow cytometry analysis showed rare negative influence by porous Se@SiO₂ nanocomposites but significantly protective effect against H₂O₂ by reducing ROS level (detected by DCFH-DA). In vivo, the biosafety of porous Se@SiO₂ nanocomposites were confirmed by the serum biochemistry, the ROS level in serum were significantly reduced and the curative effect were confirmed by Micro CT scan, serum Elisa assay (inflammatory factors), Western blotting (quantitative measurement of ONFH) and HE staining. It is expected that the porous Se@SiO₂ nanocomposites may prevent steroid-induced ONFH by reducing oxidative stress.

Interplay between autophagy and apoptosis in selenium deficient cardiomyocytes in chicken

Dietary selenium (Se) deficiency can cause heart dysfunction, however the exact mechanism remains unclear. To understand this mechanism, 180day-old chicks, divided into two groups, C (control group) and L (low Se group), were fed with either a Se-sufficient (0.23mg/kg) or Se-deficient (0.033mg/kg) diets for 25days, respectively. Heart tissues and blood samples were collected. In L group, the activities of serum creatine kinase (CK) and creatine kinase-myoglobin (CK-MB) increased and typical ultrastructural apoptotic features were observed. Se deficiency up-regulated the mRNA levels of Cysteinyl aspartate specific proteinase 3 (Caspase-3), Cysteinyl aspartate specific proteinase 8 (Caspase-8), Cysteinyl aspartate specific proteinase 9 (Caspase-9), B cell lymphoma/leukemia 2 (Bcl-2), Bcl-2 Associated X Protein (Bax), (P<0.05), whereas, the mRNA levels of Microtubuleassociated protein light chains 3-1 (LC3-1), Autophagy associated gene 5 (ATG-5), Mammalian target of rapamycin (mTOR), Dynein and Becline-1 were down-regulated (P<0.05). Noticeably, Microtubuleassociated protein light chains 3-2 (LC3-2) mRNA level increased (P<0.05) by 20%. Western blot results showed that Se deficiency decreased the expression of Becline-1 and LC3-1 protein, however, the expression of Bax, Caspase-3 and Cysteinyl aspartate specific proteinase 12 (Caspase-12) increased at protein levels. The present study revealed that Se deficiency induced apoptosis while inhibited autophagy in chicken cardiomyocytes through Bax/Bcl-2 inhibition and caspases-mediated cleavage of Becline-1. Moreover, correlation analysis illustrates that apoptosis and autophagy might function contradictorily. Altogether we conclude that Se deficient chicken cardiomyocytes experienced apoptosis rather than autophagy which is considered to be more pro-survival.

The Protective Effect of Selenium on Chronic Zearalenone-Induced Reproductive System Damage in Male Mice

This study aims to explore the protective effect of selenium (Se) on chronic zearalenone (ZEN)-induced reproductive system damage in male mice and the possible protective molecular mechanism against this. The chronic ZEN-induced injury mouse model was established with the continuous intragastric administration of 40 mg/kg body mass (B.M.) ZEN for 28 days. Then, interventions with different doses (0.1, 0.2, and 0.4 mg/kg B.M.) of Se were conducted on mice to analyse the changes in organ indexes of epididymis and testis, antioxidant capability of testis, serum level of testosterone, sperm concentration and motility parameters, and the expression levels of apoptosis-associated genes and blood testis barrier- (BTB) related genes. Our results showed that Se could greatly improve the ZEN-induced decrease of epididymis indexes and testis indexes. Results also showed that the decrease in sperm concentration, sperm normality rate, and sperm motility parameters, including percentage of motile sperm (motile), tropism percentage (progressive) and sperm average path velocity (VAP), caused by ZEN were elevated upon administration of the higher dose (0.4 mg/kg) and intermediate dose (0.2 mg/kg) of Se. Selenium also significantly reduced the content of malondialdehyde (MDA) but enhanced the activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the testis tissue. Further research demonstrated that ZEN increased the level of mRNA expression of BCL2-associated X protein (Bax) and caspase 3 (Casp3), decreased the level of mRNA expression of B cell leukemia/lymphoma 2 (Bcl2), vimentin (Vim) and cadherin 2 (Cdh2), whereas the co-administration of Se reversed these gene expression levels. Our results indicated that high levels of Se could protect against reproductive system damage in male mice caused by ZEN and the mechanism might such be that Se improved mice antioxidant ability, inhibited reproductive cell apoptosis, and increased the decrease of BTB integrity-related genes caused by ZEN.

Excessive Selenium Supplementation Induced Oxidative Stress and Endoplasmic Reticulum Stress in Chicken Spleen

Excessive selenium (Se) intake is harmful for animals and humans. The aim of the present study was to examine the effect of long-term excessive Se supplementation on oxidative stress and endoplasmic reticulum (ER) stress-related injuries in chicken spleen. A total of 180 1-day-old chickens were randomly divided into four groups with different Se dietary contents (0.2 mg/kg Se, 5 mg/kg Se, 10 mg/kg Se, or 15 mg/kg Se) for 45 days. Then, the levels of antioxidative enzymes, GPx, SOD, and MDA as well as the expression levels of GRP78, ARF6, caspase 3, caspase 12, and Bcl 2 in the spleen were determined at days 15, 30, and 45, respectively. The results showed that excessive Se treatment decreased the activities of GPx and SOD (P < 0.05) but increased the levels of MDA (P < 0.05) in a dose- and time-dependent manner. In addition, the ER stress genes GRP78 and ATF6 were highly expressed (P < 0.05), and the apoptosis genes caspase 3 and caspase 12 were increased, but Bcl 2 was decreased by Se treatment (P < 0.05). Correlation analysis showed that there was a high correlation between these biomarkers, which indicated that ER stress and ER stress-related apoptosis were correlated with oxidative stress. These results showed the important role of oxidative stress and ER stress in Se-related immune injuries in chicken.

Dietary selenium increases the antioxidant levels and ATPase activity in the arteries and veins of poultry

Selenium (Se) deficiency is associated with the pathogenesis of vascular diseases. It has been shown that oxidative levels and ATPase activity were involved in Se deficiency diseases in humans and mammals; however, the mechanism by how Se influences the oxidative levels and ATPase activity in the poultry vasculature is unclear. We assessed the effects of dietary Se deficiency on the oxidative stress parameters (superoxide dismutase, catalase, and hydroxyl radical) and ATPase (Na(+)K(+)-ATPase, Ca(++)-ATPase, Mg(++)-ATPase, and Ca(++)Mg(++)-ATPase) activity in broiler poultry. A total of 40 broilers (1-day old) were randomly divided into a Se-deficient group (L group, fed a Se-deficient diet containing 0.08 mg/kg Se) and a control group (C group, fed a diet containing sodium selenite at 0.20 mg/kg Se). Then, arteries and veins were collected following euthanasia when typical symptoms of Se deficiency appeared. Antioxidant indexes and ATPase activity were evaluated using standard assays in arteries and veins. The results indicated that superoxide dismutase activity in the artery according to dietary Se deficiency was significantly lower (p < 0.05) compared with the C group. The catalase activity in the veins and hydroxyl radical inhibition in the arteries and veins by dietary Se deficiency were significantly higher (p < 0.05) compared with the C group. The Se-deficient group showed a significantly lower (p < 0.05) tendency in Na(+)K(+)-ATPase activity, Ca(++)-ATPase activity, and Ca(++)Mg(++)-ATPase activity. There were strong correlations between antioxidant indexes and Ca(++)-ATPase activity. Thus, these results indicate that antioxidant indexes and ATPases may have special roles in broiler artery and vein injuries under Se deficiency.

Effect of Selenium Deficiency on Nitric Oxide and Heat Shock Proteins in Chicken Erythrocytes

Selenium (Se) deficiency induces various types of diseases, including hemolytic anemia, which is one of the basic pathologies of erythrocyte damage. To investigate the effect of Se deficiency on chicken erythrocytes, we detected the effects of Se deficiency on the nitric oxide (NO) content and the levels of heat shock proteins (Hsps) in chicken erythrocytes, including Hsp27, Hsp40, Hsp60, Hsp70, and Hsp90. One-day-old chickens (180) were randomly divided into two groups, a low-Se group (L group, fed with a 0.008 mg/kg Se diet) and a control group (C group, fed with a 0.2 mg/kg Se diet). Next, erythrocytes were collected at 35 days old, and the NO content, activity of inducible nitric oxide synthase (iNOS), and levels of Hsps (27, 40, 60, 70, and 90) were examined. Compared with the C group, the NO and iNOS levels were significantly higher (P < 0.05), and the Hsps in the mRNA and protein levels were generally higher (P < 0.05) in the L group. Meanwhile, the correlation analysis showed that there were positive correlations between Hsps and NO. Thus, as typical damage biomarkers, NO and Hsps may play special roles in chicken erythrocyte injury by Se deficiency.

Grass carp (Ctenopharyngodon idella) ATF6 (activating transcription factor 6) modulates the transcriptional level of GRP78 and GRP94 in CIK cells

ATF transcription factors are stress proteins containing alkaline area-leucine zipper and play an important role in endoplasmic reticulum stress. ATF6 is a protective protein which regulates the adaptation of cells to ER stress by modulating the transcription of UPR (Unfolded Protein Response) target genes, including GRP78 and GRP94. In the present study, a grass carp (Ctenopharyngodon idella) ATF6 full-length cDNA (named CiATF6, KT279356) has been cloned and identified. CiATF6 is 4176 bp in length, comprising 159 nucleotides of 5'-untranslated sequence, a 1947 nucleotides open reading frame and 2170 nucleotides of 3'-untranslated sequences. The largest open reading frame of CiATF6 translates into 648 aa with a typical DNA binding domain (BRLZ domain) and shares significant homology to the known ATF6 counterparts. Phylogenetic reconstruction confirmed its closer evolutionary relationship with other fish counterparts, especially with Zebrafish ATF6. RT-PCR showed that CiATF6 was ubiquitously expressed and significantly up-regulated after stimulation with thermal stress in all tested grass carp tissues. In order to know more about the role of CiATF6 in ER stress, recombinant CiATF6N with His-tag was over-expressed in Rosetta Escherichia coli, and the expressed protein was purified by affinity chromatography with Ni-NTA His-Bind Resin. In vitro, gel mobility shift assays were employed to analyze the interaction of CiATF6 protein with the promoters of grass carp GRP78 and GRP94, respectively. The result has shown that CiATF6 could bind to these promoters with high affinity by means of its BRLZ mainly. To further study the transcriptional regulatory mechanism of CiATF6, Dual-luciferase reporter assays were applied. Recombinant plasmids of pGL3-GRP78P and pGL3-CiGRP94P were constructed and transiently co-transfected with pcDNA3.1-CiATF6 (pcDN3.1-CiATF6-nBRLZ, respectively) into C. idella kidney (CIK) cells. The result has shown that CiATF6 could activate CiGRP78 and CiGRP94 promoters.

Role of ZnS Nanoparticles on Endoplasmic Reticulum Stress-mediated Apoptosis in Retinal Pigment Epithelial Cells

Age-related macular degeneration (AMD) is the leading cause for irreversible visual impairment affecting 30-50 million individuals every year. Oxidative stress and endoplasmic reticulum stress have been identified as crucial factors for the pathogenesis of AMD. Current treatments do not focus on underlying stimuli responsible for the disease like AMD. Zinc is an important trace metal in retina and its deficiency leads to AMD. Recent studies on zinc sulphide nanoparticles (ZnS-NPs) are gaining attention in the field of physical and biological research. In this present study, in investigating the role of ZnS-NPs on hydrogen peroxide and thapsigargin-treated primary mice retinal pigment epithelial (MRPE) cells, we synthesized ZnS-NPs and characterized using atomic force microscope (AFM) and SEM-EDX. The ZnS-NPs abrogate the primary MRPE cell death through inhibition of oxidative stress-induced reactive oxygen species production and cell permeability. Oxidant molecules hydrogen peroxide and thapsigargin alter unfolded protein response such as glucose-regulated protein 78 (GRP78) and C/EBP homology protein (CHOP) expressions, whereas ZnS-NPs-pre-treated primary MRPE cells downregulated the overexpression of such proteins. The expressions of apoptotic proteins caspase 12 and cleaved caspase 9 and caspase 3 were also significantly controlled in ZnS-NPs-treated primary MRPE cells when comparing with thapsigargin- and hydrogen peroxide-treated cells. From these results, ZnS-NPs stabilize reactive oxygen species elevation, when subjected to hydrogen peroxide- and thapsigargin-mediated oxidant injury and helps in maintaining normal homeostasis through regulating endoplasmic reticulum (ER) stress response proteins which is the lead cause for apoptosis-mediated pathogenesis of AMD.

SelW regulates inflammation-related cytokines in response to H2O2in Se-deficient chicken liver

Selenium (Se) deficiency-induced liver damage is related to oxidative stress, and the alternative transcription of cytokines has been linked to liver disease.