Heat shock protein 70 protects cardiomyocytes through suppressing SUMOylation and nucleus translocation of phosphorylated eukaryotic elongation factor 2 during myocardial ischemia and reperfusion.

Myocardial ischemia and reperfusion (MIR) results in cardiomyocyte apoptosis with severe outcomes, which blocks cardiac tissue recovering from myocardial ischemia diseases. Heat shock protein 70 (HSP70) is one of protective molecule chaperones which could regulate the nucleus translocation of other proteins. In addition, eukaryotic elongation factor 2 (eEF2), which modulates protein translation process, is vital to the recovery of heart during MIR. However, the relationship between HSP70 and eEF2 and its effects on MIR are unclear. The expression and relationship between HSP70 and eEF2 is confirmed by western blot, immunoprecipitation in vitro using cardiomyocyte cell line H9c2 and in vivo rat MIR model. The further investigation was conducted in H9c2 cells with detection for cell-cycle and apoptosis. It is revealed that eEF2 interacted and be regulated by HSP70, which kept eEF2 as dephosphorylated status and preserved the function of eEF2 during MIR. In addition, HSP70 suppressed the nucleus translocation of phosphorylated eEF2, which inhibited cardiomyocyte apoptosis during myocardial reperfusion stage. Furthermore, HSP70 also interacted with C-terminal fragment of eEF2, which could reverse the nucleus translocation and cardiomyocyte apoptosis caused by N-terminal fragment of eEF2. HSP70 draw on advantage and avoid defect of MIR through regulating phosphorylation and nucleus translocation of eEF2.

Potential Vaccine Targets against Rabbit Coccidiosis by Immunoproteomic Analysis.

The aim of this study was to identify antigens for a vaccine or drug target to control rabbit coccidiosis. A combination of 2-dimensional electrophoresis, immunoblotting, and mass spectrometric analysis were used to identify novel antigens from the sporozoites of Eimeria stiedae. Protein spots were recognized by the sera of New Zealand rabbits infected artificially with E. stiedae. The proteins were characterized by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF/TOF-MS) analysis in combination with bioinformatics. Approximately 868 protein spots were detected by silver-staining, and a total of 41 immunoreactive protein spots were recognized by anti-E. stiedae sera. Finally, 23 protein spots were successfully identified. The proteins such as heat shock protein 70 and aspartyl protease may have potential as immunodiagnostic or vaccine antigens. The immunoreactive proteins were found to possess a wide range of biological functions. This study is the first to report the proteins recognized by sera of infected rabbits with E. stiedae, which might be helpful in identifying potential targets for vaccine development to control rabbit coccidiosis.

PKR promotes choroidal neovascularization via upregulating the PI3K/Akt signaling pathway in VEGF expression.

PURPOSE: The aim of this study was to investigate the functions of dsRNA-activated protein kinase (PKR) in choroidal neovascularization (CNV) and related signaling pathways in the production of vascular endothelial growth factor (VEGF). METHODS: A chemical hypoxia model of in vitro RF/6A cells, a rhesus choroid-retinal endothelial cell line, was established by adding cobalt chloride (CoCl2) to the culture medium. PKR, phosphophosphatidylinositol 3-kinase (p-PI3K), phosphoprotein kinase B (p-Akt), and VEGF protein levels in RF/6A cells were detected with western blotting. PKR siRNA and the PI3K inhibitor LY294002 were used to evaluate the roles of the PKR and PI3K signaling pathways in VEGF expression with western blotting. In an ARPE-19 (RPE cell line) and RF/6A cell coculture system, proliferation, migration, and tube formation of RF/6A cells under hypoxic conditions were measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), Transwell, and Matrigel Transwell assays, respectively. In vivo CNV lesions were induced in C57BL/6J mice using laser photocoagulation. The mice were euthanized in a timely manner, and the eyecups were dissected from enucleated eyes. PKR, p-PI3K, p-Akt, and VEGF protein levels in tissues were detected with western blotting. To evaluate the leakage area, fundus fluorescein angiography and choroidal flat mount were performed on day 7 after intravitreal injection of an anti-PKR monoclonal antibody. RESULTS: The in vitro RF/6A cell chemical hypoxia model showed that PKR expression was upregulated in parallel with p-PI3K, p-Akt, and VEGF expression, peaking at 12 h. PKR siRNA downregulated PKR, p-PI3K, p-Akt, and VEGF expression. In addition, the PI3K inhibitor LY294002 greatly decreased the p-PI3K, p-Akt, and VEGF protein levels, but PKR expression was unaffected, indicating that Akt was a downstream molecule of PKR that upregulated VEGF expression. In the ARPE-19 (RPE cell line) and RF/6A cell coculture system, PKR siRNA reduced the migration and tube formation of the RF/6A cells. In vivo, PKR, p-PI3K, p-Akt, and VEGF expression increased and peaked at 7 days in the mouse CNV model induced by laser photocoagulation. Furthermore, on the RPE and choroid cryosections, PKR colocalized with CD31, suggesting that PKR was expressed by the vascular endothelium. The intravitreal injection of an anti-PKR monoclonal antibody decreased the progression and leakage area of CNV in mice. CONCLUSIONS: PKR promotes CNV formation via the PI3K/Akt signaling pathway in VEGF expression. Additionally, the anti-PKR monoclonal antibody significantly decreased CNV in a mouse model, showing the antibody may have therapeutic potential in human CNV.

Butylated hydroxyanisole induces distinct expression patterns of Nrf2 and detoxification enzymes in the liver and small intestine of C57BL/6 mice.

Butylated hydroxyanisole (BHA) is widely used as an antioxidant and preservative in food, food packaging and medicines. Its chemopreventive properties are attributing to its ability to activate the transcription factor NF-E2 p45-related factor 2 (Nrf2), which directs central genetic programs of detoxification and protection against oxidative stress. This study was to investigate the histological changes of Nrf2 and its regulated phase II enzymes Nqo1, AKR1B8, and Ho-1 in wild-type (WT) and Nrf2(-/-) mice induced by BHA. The mice were given a 200mg/kg oral dose of BHA daily for three days. Immunohistochemistry revealed that, in the liver from WT mice, BHA increased Nqo1 staining in hepatocytes, predominately in the pericentral region. In contrast, the induction of AKR1B8 appeared mostly in hepatocytes in the periportal region. The basal and inducible Ho-1 was located almost exclusively in Kupffer cells. In the small intestine from WT mice, the inducible expression patterns of Nqo1 and AKR1B8 were nearly identical to that of Nrf2, with more intense staining in the villus than that the crypt. Conversely, Keap1 was more highly expressed in the crypt, where the proliferative cells reside. Our study demonstrates that BHA elicited differential expression patterns of phase II-detoxifying enzymes in the liver and small intestine from WT but not Nrf2(-/-) mice, demonstrating a cell type specific response to BHA in vivo.

Comparison of the effects of three cryoprotectants on the cryopreservation of mouse subcutaneous tissue under different conditions.

The subcutaneous tissue of animals contains different cell types, and different cells have different requirements for cryopreservation. This establishes obstacles that need to be overcome in the clinical application of tissue preservation. In the present study, the effects of different freezing rates and various concentrations of cryoprotectants on the cryopreservation of subcutaneous tissue of mice were compared, and these results provided basic research data that can be used to explore the optimal cryopreservation method for tissue. The effects of three cryoprotectants, dimethyl sulfoxide, glycerinum and 1,2-propanediol, and their concentrations on the cryopreservation of subcutaneous tissue of mice were compared with slow and rapid freezing rates. The results revealed that under various cryopreservation conditions, the percentage of fibroblasts that grow from the tissue following slow cryopreservation (19.8%) was significantly higher than that following rapid freezing (6.7%) at osmotic equilibrium for 10-20 min (P<0.05). After 19 days of culture, under the conditions of slow freezing, with 10, 20 and 30% glycerinum as a cryoprotectant, respectively, fibroblasts grew from 26.0, 16.7 and 16.7% of the tissues, respectively. No fibroblasts were indicated in the tissue mass cultured in any other tissue blocks treated with cryopreservation solutions. Under the condition of rapid freezing, fibroblasts grew from 6.7 and 6.7% tissue blocks of 20% DMSO and 10% glycerinum, respectively, following 19 days of culture. No fibroblasts were identified in the tissue mass cultured in the other tissue blocks treated with cryopreservation solutions, and no fibroblasts were identified in the tissue blocks without osmotic balance before freezing.

Genome-wide global identification of NRF2 binding sites in A549 non-small cell lung cancer cells by ChIP-Seq reveals NRF2 regulation of genes involved in focal adhesion pathways.

Nuclear factor erythroid-derived-2-like 2(NRF2) regulates its downstream genes through binding with antioxidant responsive elements in their promoter regions. Hyperactivation of NRF2 results in oncogenesis and drug resistance in various cancers including non-small cell lung cancer (NSCLC). However, identification of the genes and pathways regulated by NRF2 in NSCLC warrants further investigation. We investigated the global NRF2 genomic binding sites using the high-throughput ChIP-Seq technique in KEAP1 (Kelch-like ECH-associated protein 1)-mutated A549 (NSCLC) cells. We next carried out an integrated analysis of the ChIP-Seq data with transcriptomic data from A549 cells with NRF2-knockdown and RNA-Seq data from TCGA patients with altered KEAP1 to identify downstream and clinically-correlated genes respectively. Furthermore, we applied transcription factor enrichment analysis, generated a protein-protein interaction network, and used kinase enrichment analysis. Moreover, functional annotation of NRF2 binding sites using DAVID v7 identified the genes involved in focal adhesion. Putative focal adhesion genes regulated by NRF2 were validated using qRT-PCR. Further, we selected one novel conserved focal adhesion gene regulated by NRF2-LAMC1 (laminin subunit gamma 1) and validated it using a reporter assay. Overall, the identification of NRF2 target genes paves the way for identifying the molecular mechanism of NRF2 signaling in NSCLC development and therapy. Moreover, our data highlight the complexity of the pathways regulated by NRF2 in lung tumorigenesis.

Mkp-1 protects mice against toxin-induced liver damage by promoting the Nrf2 cytoprotective response.

The present study was undertaken to investigate the possible protective effect of mitogen-activated protein kinase phosphatase 1 (Mkp-1) on toxin-induced hepatic injury. Here, we uncovered a positive feedback loop between Mkp-1, a dual threonine/tyrosine phosphatase, and nuclear factor erythroid 2-related factor 2 (Nrf2), a crucial regulator of the defense system in the liver. Mkp-1-/- mice exhibited decreased protein levels of Nrf2, phase II gene products, and reduced glutathione (GSH) in the liver. Induction of detoxifying enzymes by the Nrf2 activator butylated hydroxyanisole (BHA) or sulforaphane, was attenuated in the liver and small intestines of Mkp-1-/- mice, indicating that the Nrf2 signaling pathway is impaired as a result of Mkp-1 deficiency. Mkp-1-/- mice suffered more severe liver injury after a single exposure to hepatotoxin carbon tetrachloride (CCl4) than their wild-type (WT) counterparts. BHA partially rescued the CCl4-induced liver damage in WT mice, but not in Mkp-1-/- mice, suggesting the requirement of Mkp-1 in the activation of Nrf2 signaling against the liver injury. Mechanistically, Mkp-1 upregulated Nrf2 through a direct interaction with the Neh2 domain in the transcription factor, while Nrf2 enhanced the expression of Mkp-1 mRNA by binding to the ARE site at -1719 to -1710bp in the Mkp-1 promoter. Our results reveal novel role of Mkp-1 in the maintenance of redox homeostasis in the liver. Thus, strategies aimed at augmenting Mkp-1 expression may be beneficial in protecting the liver and may provide novel therapeutic approaches to toxin-induced liver injury.

Identification of causative pathogens in mouse eyes with bacterial keratitis by sequence analysis of 16S rDNA libraries.

The clone library method using PCR amplification of the 16S ribosomal RNA (rRNA) gene was used to identify pathogens from corneal scrapings of C57BL/6-corneal opacity (B6-Co) mice with bacterial keratitis. All 10 samples from the eyes with bacterial keratitis showed positive PCR results. All 10 samples from the normal cornea showed negative PCR results. In all 10 PCR-positive samples, the predominant and second most predominant species accounted for 20.9 to 40.6% and 14.7 to 26.1%, respectively, of each clone library. The predominant species were Staphylococcus lentus, Pseudomonas aeruginosa, and Staphylococcus epidermidis. The microbiota analysis detected a diverse group of microbiota in the eyes of B6-Co mice with bacterial keratitis and showed that the causative pathogens could be determined based on percentages of bacterial species in the clone libraries. The bacterial species detected in this study were mostly in accordance with results of studies on clinical bacterial keratitis in human eyes. Based on the results of our previous studies and this study, the B6-Co mouse should be considered a favorable model for studying bacterial keratitis.

Differential expression patterns of Nqo1, AKR1B8 and Ho-1 in the liver and small intestine of C57BL/6 mice treated with sulforaphane.

This data article contains complementary figures and results related to the research article entitled "butylated hydroxyanisole induces distinct expression patterns of Nrf2 and detoxification enzymes in the liver and small intestine of C57BL/6 mice" (Luo et al., 2015 [1]), which defined the basal and butylated hydroxyanisole (BHA)-induced expression patterns of Phase II enzymes Nqo1, AKR1B8, and Ho-1 in the liver and small intestine of C57BL/6 mice. Sulforaphane [1-isothiocyanato-4-(methylsulfinyl)butane] (SFN), a naturally occurring isothiocyanate derived from cruciferous vegetables, is a highly potent inducer of phase II cytoprotective enzymes. This dataset reports the histological changes of Nqo1, AKR1B8, and Ho-1 in wild-type (WT) and Nrf2 (-/-) mice induced by SFN. The mice were given a 25 mg/kg single oral dose of SFN for 24 h and 48 h. Immunohistochemistry revealed that, in the liver from WT mice, SFN increased Nqo1 staining in hepatocytes with slight higher staining in the pericentral region. The induction of AKR1B8 appeared mostly in hepatocytes in the periportal region. The basal and inducible Ho-1 was located predominately in Kupffer cells. In the small intestine from WT mice, the inducible expression of Nqo1 and AKR1B8 appeared more obvious in the villus than that in the crypt.