Selenium Deficiency Influences the Gene Expressions of Heat Shock Proteins and Nitric Oxide Levels in Neutrophils of Broilers

The aim of the present study was to investigate the effects of selenium (Se) deficiency on the expressions of heat shock proteins (Hsp90, 70, 60, 40, and 27) and nitric oxide (NO) levels in neutrophils of broilers. One hundred eighty 1-day-old broilers were randomly assigned into two groups and were fed on a low-Se diet (0.008 mg/kg Se) or a control diet (0.2 mg/kg Se), respectively. Then, the messenger RNA (mRNA) levels of Hsp90, 70, 60, 40, and 27, induced nitric oxide synthase (iNOS), and NO levels were examined. The results showed that Se deficiency increased the mRNA levels of Hsps and iNOS and induced higher level of NO in chicken neutrophils (P?iNOS had the biggest correlation with Hsp60, which indicated that Hsp60 might play an important function in inhibiting the production of NO, and the correlation coefficient between Hsp60 and Hsp70 was over 0.9, which indicated that they might have a synergistic effect. These results suggested that the level of NO and Hsp expression levels in neutrophils can be influenced by Se deficiency. And Hsp40 might play the crucial protective role in neutrophils induced by Se deficiency.     

Alpha-Synuclein Oligomerization in Manganese-Induced Nerve Cell Injury in Brain Slices: A Role of NO-Mediated S-Nitrosylation of Protein Disulfide Isomerase

Over-exposure to manganese (Mn) has been known to induce endoplasmic reticulum (ER) stress involving protein misfolding. The proper maturation and folding of native proteins rely on the activity of protein disulfide isomerase (PDI). However, the exact mechanism of Mn-induced alpha-synuclein oligomerization is unclear. To explore whether alpha-synuclein oligomerization was associated with S-nitrosylation of PDI, we made the rat brain slice model of manganism and pretreated slices with l-Canavanine, a selective iNOS inhibitor. After slices were treated with Mn (0, 25, 100, and 400 μM) for 24 h, there were dose-dependent increases in apoptotic percentage of cells, lactate dehydrogenase (LDH) releases, production of NO, inducible nitric oxide synthase (iNOS) activity, the mRNA and protein expressions of iNOS, and PDI. Moreover, S-nitrosylated PDI and alpha-synuclein oligomerization also increased. However, there was a significant increase in the PDI activity of 25-μM Mn-treated slices. Then, PDI activity and the affinity between PDI and alpha-synuclein decreased significantly in response to Mn (100 and 400 μM), which was associated with S-nitrosylation of PDI. The results indicated that S-nitrosylated PDI could affect its activity. We use the l-Canavanine pretreatment brain slices to inhibit S-nitrosylation of PDI. The results showed that l-Canavanine pretreatment could reduce Mn-induced nerve cell injury and alpha-synuclein oligomerization. Additionally, there was a significant recovery in PDI activity in l-Canavanine-pretreated slices. The findings revealed that Mn induced nitrosative stress via the activation of iNOS and subsequent S-nitrosylation of PDI in cultured slices. Moreover, S-nitrosylation of PDI is an important signaling event in the Mn-induced alpha-synuclein oligomerization in brain slices.     

GDNF is Involved in the Barrier-Inducing Effect of Enteric Glial Cells on Intestinal Epithelial Cells Under Acute Ischemia Reperfusion Stimulation

Acute intestinal ischemia reperfusion (IR) injury is often associated with intestinal epithelial barrier (IEB) dysfunction. Enteric glial cells (EGCs) play an essential role in maintaining the integrity of IEB functions. However, the precise mechanism of EGCs under IR stimulation remains unclear. Here, we report that EGCs are closely involved in the modulation of IEB functions in response to IR challenge. The intestinal IR treatment led to the significant upregulation of the EGC activation marker, glial fibrillary acidic protein, accompanied by the increasing abundance of glial-derived neurotrophic factor (GDNF) and inducible nitric oxidase (iNOS) proteins, which was also confirmed in in vitro hypoxia reoxygenation (HR) tests. Co-culturing with EGCs attenuated the tight junctional abnormalities, blocked the downregulation of ZO-1 and occludin protein expression, and relieved the decrease of permeability of intestinal epithelial cell (IEC) monolayers under HR treatment. Furthermore, exogenous GDNF administration displays the barrier-protective effects similar to EGCs against HR stimulation, while RNA interference-mediated knockdown of GDNF significantly inhibited the protective capability of EGCs. The expression of both GDNF and iNOS proteins of EGCs was significantly upregulated by co-culturing with IECs, which was further increased by HR treatment. Interestingly, through inhibiting iNOS activity, the barrier-protective effect of EGCs was influenced in normal condition but enhanced in HR condition. These results suggest that GDNF plays an important role in the barrier-protective mechanism of activated EGCs under IR stimulation, whereas EGCs (via iNOS release) are also involved in intestinal inflammation response, which may contribute to IEB damage induced by IR injury.     

Possible Correlation of Selenoprotein W with Inflammation Factors in Chicken Skeletal Muscles

The aim of the present study was to investigate the possible correlation of selenoprotein W (SelW) with inflammatory injury induced by dietary selenium (Se) deficiency in chicken. One-day-old male chickens were fed either a commercial diet or a Se-deficient diet for 55 days. Then, the expression levels of SelW messenger RNA (mRNA) and inflammation-related genes (NF-κB, TNF-α, iNOS, COX-2, and PTGES) in chicken skeletal muscles (wing muscle, pectoral muscle, and thigh muscle) were determined at 15, 25, 35, 45, and 55 days old, respectively. In addition, the correlation between SelW mRNA expression and inflammation-related genes were assessed. The results showed that dietary Se deficiency reduced the mRNA expression of SelW in chicken wing, pectorals, and thigh muscles. In contrast, Se deficiency increased the mRNA expression levels of inflammation-related genes in chicken skeletal muscle tissues at different time points. The Pearson’s correlation coefficients showed that the mRNA expression levels of inflammation-related genes were significantly negative related to SelW (p?相似文献   

Apparent Reduction of ADAM10 in Scrapie-Infected Cultured Cells and in the Brains of Scrapie-Infected Rodents

It has been described that A disintegrin and metalloproteinase (ADAM10) may involve in the physiopathology of prion diseases, but the direct molecular basis still remains unsolved. In this study, we confirmed that ADAM10 was able to cleave recombinant human prion protein in vitro. Using immunoprecipitation tests (IP) and immunofluorescent assays (IFA), reliable molecular interaction between the native cellular form of PrP (PrP^C) and ADAM10 was observed not only in various cultured neuronal cell lines but also in brain homogenates of healthy hamsters and mice. Only mature ADAM10 (after removal of its prodomain) molecules showed the binding activity with the native PrP^C. Remarkably more prion protein (PrP)-ADAM10 complexes were detected in the membrane fraction of cultured cells. In the scrapie-infected SMB cell model, the endogenous ADAM10 levels, especially the mature ADAM10, were significantly decreased in the fraction of cell membrane. IP and IFA tests of prion-infected SMB-S15 cells confirmed no detectable PrP-ADAM10 complex in the cellular lysates and PrP-ADAM10 co-localization on the cell surface. Furthermore, we demonstrated that the levels of ADAM10 in the brain homogenates of scrapie agent 263K-infected hamsters and agent ME7-infected mice were also almost diminished at the terminal stage, showing time-dependent decreases during the incubation period. Our data here provide the solid molecular basis for the endoproteolysis of ADAM10 on PrP molecules and interaction between ADAM10 and PrP^C. Obvious loss of ADAM10 during prion infection in vitro and in vivo highlights that ADAM10 may play essential pathophysiological roles in prion replication and accumulation.     

Polymorphism of DNA Repair Gene xrcc1 and Lung Cancer Risk

The current large-scale meta-analysis was performed to reach a reliable conclusion on the association between X-ray repair cross-complementing 1 (xrcc1) rs1799782 and the development of lung cancer. Studies that investigated the association between rs1799782 and lung cancer risk were identified by searching PubMed. We calculated odds ratio (OR) with corresponding 95 % confidence interval (CI) for Trp/Trp vs Arg/Arg, Trp/Trp + Arg/Trp vs Arg/Arg, and Trp/Trp vs Arg/Trp + Arg/Arg contrast models. Combining all 25 studies, we yielded three summary ORs: 1.07 (95 % CI 0.92–1.23) for Trp/Trp vs Arg/Arg, 0.93 (95 % CI 0.87–1.00) for Trp/Trp + Arg/Trp vs Arg/Arg, and 1.08 (95 % CI 0.94–1.25) for Trp/Trp vs Arg/Trp + Arg/Arg, suggesting rs1799782 was not associated with overall risk of lung cancer. Strikingly, a significantly deceased risk was found among Caucasian populations (Trp/Trp + Arg/Trp vs Arg/Arg, OR = 0.86, 95 % CI 0.76–0.97). This study confirms that xrcc1 rs1799782 may lower the risk of lung cancer among Caucasians.     

Mechanism of bFGF-binding Peptide Reversing Adriamycin Resistance in Human Gastric Cancer Cells

Development of drug resistance is a challenging problem in cancer chemotherapy. It has been shown that basic fibroblast growth factor (bFGF) plays an important role in an epigenetic mechanism of drug resistance. We have isolated a bFGF binding peptide P7 with inhibitory activity against bFGF-induced proliferation of human gastric cancer cells by screening a phage display library. In this study, we found that P7 peptide also has efficacy of reversing bFGF-induced resistance to Adriamycin (ADM) in human gastric cancer cells. Further investigations with SGC-7901 cells revealed that inhibition of Akt activation triggered by bFGF, and reversal of bFGF-induced up-regulation of Bcl-2 and XIAP and down-regulation of Bax, contribute to P7 peptide counteracting the anti-apoptotic effect of bFGF, and further reversing bFGF-induced resistance to ADM. The results suggested that the bFGF-binding peptide may have therapeutic potential of drug resistance in gastric cancer.     

EGFR-AKT-mTOR activation mediates epiregulin-induced pleiotropic functions in cultured osteoblasts

Epidermal growth factor (EGF) receptor (EGFR) emerges as an essential molecule for the regulating of osteoblast cellular functions. In the current study, we explored the effect of epiregulin, a new EGFR ligand, on osteoblast functions in vitro, and studied the underlying mechanisms. We found that epiregulin-induced EGFR activation in both primary osteoblasts and osteoblast-like MC3T3-E1 cells. Meanwhile, epiregulin activated AKT-mammalian target of rapamycin (mTOR) and Erk-mitogen-activated protein kinase (MAPK) signalings in cultured osteoblasts, which were blocked by EGFR inhibitor AG1478 or monoclonal antibody against EGFR (anti-EGFR). Further, in primary and MC3T3-E1 osteoblasts, epiregulin promoted cell proliferation and increased alkaline phosphatase activity, while inhibiting dexamethasone (Dex)-induced cell death. Such effects by epiregulin were largely inhibited by AG1478 or anti-EGFR. Notably, AKT-mTOR inhibitors, but not Erk inhibitors, alleviated epiregulin-induced above pleiotropic functions in osteoblasts. Meanwhile, siRNA depletion of Sin1, a key component of mTOR complex 2 (mTORC2), also suppressed epiregulin-exerted effects in MC3T3-E1 cells. Together, these results suggest that epiregulin-induced pleiotropic functions in cultured osteoblasts are mediated through EGFR-AKT-mTOR signalings.     

Deep-sea water inhibits metastatic potential in HT-29 human colorectal adenocarcinomas via MAPK/NF-κB signaling pathway

A previous investigation showed that deep-sea water (DSW) can affect the expression of genes that regulate metastasis, including cyclooxygenase-2 (COX-2), matrix metalloproteinase-2 (MMP-2), urokinase plasminogen activator (uPA) and uPA receptor (uPAR), in HT-29 human colorectal adenocarcinomas. In the present study, we investigated the effects of DSW on inducible nitric oxide synthase (iNOS) expression and cell migration and also explored the mechanism of DSW-induced anti-metastatic potential in HT-29 human colorectal adenocarcinomas. Cytokine-induced expression of iNOS, which is highly expressed in colon cancer and enhances cancer growth and metastasis, was decreased in a hardness-dependent manner by DSW. Also, the wound healing assay revealed that DSW inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cell migration in a hardness-dependent manner. DSW also decreased the phosphorylation of various MAPKs, including p38, ERK and JNK, and suppressed the nuclear translocation of NF-κB but not c-Jun. The results suggest that DSW may inhibit cancer cell growth related to iNOS overexpression and PKC-mediated cell migration in HT-29 human colorectal adenocarcinomas and the antimetastatic potential of DSW may be regulated by prevention of NF-κB nuclear translocation via inhibition of p38, ERK and JNK phosphorylation. In conclusion, the present investigation demonstrates that DSW inhibits cancer growth and metastasis via down-regulation of iNOS expression and the MAPK/NF-κB signaling pathway.     

Expression of TNF-α, IFN-γ, TGF-β, and IL-4 in the Spinal Tuberculous Focus and Its Impact on the Disease

To investigate the expression of TNF-α, IFN-γ, TGF-β, and IL-4 in the spinal tuberculous focus and its relationship with the lesions type, severity, and bone destruction. The pathological samples of patients with spinal tuberculosis (TB) were divided into hyperplasia group and necrosis group according to their intra-operative and post-operative pathological findings. Normal bone tissues were taken as the control group. Pathology and expression of TNF-α, IFN-γ, TGF-β, and IL-4 in different tissues were compared among these three groups using immunohistochemical staining, quantitative image analysis, and measurement of bone tissue. 286 granulomas observed in the 14 samples in the hyperplasia group, which included 84 necrotizing and 202 non-necrotizing granulomas. As for the 20 samples in the necrosis group, there were 356 necrotizing and 186 non-necrotizing granulomas among all the 542 granulomas. The proportion of necrotizing granulomas in the necrosis group was significantly higher than that of the hyperplasia group. By inter-group comparison, expression of TNF-α, IFN-γ of granulomas in the hyperplasia group was significantly higher than that of the necrosis group, while the expression of TGF-β, IL-4 of granulomas in the necrosis group was significantly higher than that of the hyperplasia group. Also, expression of IFN-γ of non-necrotizing granulomas was significantly higher than that of necrotizing granulomas in the hyperplasia group, and expression of TGF-β in necrotizing granulomas was significantly higher than that of non-necrotizing granulomas in the necrosis group. The lesions were mainly bone resorption in the hyperplasia group, whereas mostly necrotic bones accompanied by local fibrosis in the necrosis group. Expression levels of TNF-α, IFN-γ in the hyperplasia group have a positive correlation to bone loss, whereas expression levels of TGF-β, IL-4 in the necrosis group have a positive correlation to the bone formation. The high expressions of TNF-α, IFN-γ in the spinal tuberculous focus were associated with protective immune cells. TGF-β and IL-4 were related to allergic lesions, fibrosis and osteogenesis. Expression imbalance of TNF-α, IFN-γ, TGF-β, and IL-4 might aggravate the allergy of TB.     

On the existence of two GABA pools associated with newly synthesized GABA and with newly taken up GABA in nerve terminals

[¹⁴C]Glutamic acid and [³H]GABA were injected into the lateral ventricle of mouse and then [¹⁴C]GABA and [³H]GABA in synaptosomes isolated from the animals were analysed. The [¹⁴C]GABA was interpreted to be newly synthesized GABA from [¹⁴C]glutamic acid while the [³H]GABA to be newly taken up GABA. We have obtained the following results: (1) when the animals were pretreated with aminooxyacetic acid and thus the GABA content in synaptosomes increased to about 2 times of the control level, only the [³H]GABA was enhanced to 3 times of the control level without any change of [¹⁴C]GABA, (2) the release of [¹⁴C]GABA from synaptosomes by high K⁺ depolarization was 1.5 times greater than that of [³H]GABA, (3) the releases of both [¹⁴C]GABA and [³H]GABA were increased in the presence of cold GABA,l-2,4-diaminobutyric acid or γ-amino-β-hydroxybutyric acid, but only slightly increased in the presence of β-alanine. These results would suggest that newly synthesized GABA and newly taken up GABA localized individually in different pools, which might localize either in different nerve terminals or separately in the same nerve terminal.     

Selenium Deficiency Influences Nitric Oxide and Selenoproteins in Pancreas of Chickens

Selenium (Se) deficiency induces pancreatic atrophy in chickens, but the molecular mechanism remains unclear. In this study, we investigated the effect of dietary Se deficiency on the expressions of 25 selenoproteins and the content of nitric oxide (NO) and examined the relationship between selenoproteins and NO. Chickens (180; 1 day old) were randomly divided into two groups, low (L) group (fed with Se deficient (Se 0.033 mg/kg) diet) and control (C) group (fed with normal (Se 0.2 mg/kg) diet). Then, pancreas was collected at 15, 25, 35, 45, and 55 days, and the content of NO, the activity of inducible NO synthase (iNOS), and the messenger RNA (mRNA) levels of 25 selenoproteins and iNOS were measured. The results showed that 25 selenoproteins were decreased (P?P?Thioredoxin reductase 2 (TXNRD2), glutathione peroxidase 1 (GPX1), glutathione peroxidase 3 (GPX3), selenoprotein I (SELI), iodothyronine deiodinase 1 (DIO1), selenoprotein P1 (SEPP1), selenoprotein W1 (SEPW1), selenoprotein O (SELO), selenoprotein T (SELT), selenoprotein M (SELM), selenoprotein X1 (SEPX1), and SPS2 were excessively decreased (P?iNOS activity, and mRNA level were increased strikingly compared with C group (P?相似文献   

The selective roles of chaperone systems on over-expression of human-like collagen in recombinant Escherichia coli

Human-like collagen (HLC) is a novel biomedical material with promising applications. Usually, insoluble HLC was formed due to over-expression. In order to improve the production of soluble HLC, the effective chaperone proteins and their mediation roles on HLC were clarified. Trigger factor (TF) pathway with low specificity and high binding affinity to nascent chains could increase soluble HLC expression; GroEL-GroES could increase the expression level of HLC by assisting the correct folding of HLC and increase mRNA level of the gene coding for HLC by enhancing mRNA stability. DnaK chaperone system did not work positively on soluble HLC due to the unbalanced ratio of DnaK:DnaJ:GrpE, especially too high GrpE significantly inhibited DnaK-mediated refolding. The production of soluble HLC with co-expression of exogenous TF and GroEL-GroES was increased by 35.3 % in comparison with the highest value 0.26 g/L reported previously.     

Up-regulation of SKIP relates to retinal ganglion cells apoptosis after optic nerve crush in vivo

Cell cycle re-entry is one of the key processes in neuronal apoptosis. Previous studies have shown that Ski-interacting protein (SKIP) played an important role in cell cycle re-entry. However, its expression and function in optic nerve injury are still with limited acquaintance. To investigate whether SKIP is involved in retinal ganglion cells (RGCs) death, we performed an optic nerve crush (ONC) model in adult rats. Western blot analysis revealed that up-regulation of SKIP was present in retina at 5 days after ONC. Immunofluorescent labeling indicated that up-regulated SKIP was found mainly in RGCs. We also investigated co-localization of SKIP with active-caspase-3 and TUNEL (apoptotic markers) -positive cells in the retina after ONC. In addition, the expression of SKIP was increased in parallel with P53 and P21 in retina after ONC. All these results suggested that up-regulation of SKIP in the retina was associated with RGCs death after ONC.     

Ribosomal RNA contents of maize genotypes with different ribosomal RNA gene numbers

Ribosomal RNA (rRNA) contents were determined in 16 maize genotypes whose individual rRNA gene numbers varied from 5000 to 23,000 per 2C nucleus. Analytical polyacrylamide gel electrophoresis of total RNA showed that no obvious relation existed between rRNA gene number and rRNA content. Only two of nine common inbred lines contained more rRNA than W-23, the inbred with the lowest rRNA gene number. Two of four lines with altered protein content (due to long-term experimental selection) had rRNA contents significantly reduced from those of W-23. A line with an apparent duplication of the nucleolus organizer region of chromosome 6 (called 2-NOR) was expected to possess an elevated quantity of rRNA because it possesses a larger nucleolus; however, we produced a 2-NOR isogenic version and found no difference in rRNA content. The rRNA genes in maize are distributed throughout the NOR-heterochromatin and the NOR-secondary constriction portions of the NOR. The absence of an obvious correlation between rRNA gene number and cellular rRNA content may reflect the presence of a large number of rRNA genes in an inactive state, at least during the stage of growth examined in these experiments.