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Sample records for comparing hypoxia-induced gene

  1. Screening of hypoxia-inducible genes in sporadic ALS.

    LENUS (Irish Health Repository)

    Cronin, Simon

    2008-10-01

    Genetic variations in two hypoxia-inducible angiogenic genes, VEGF and ANG, have been linked with sporadic amyotrophic lateral sclerosis (SALS). Common variations in these genes may reduce the levels or functioning of their products. VEGF and ANG belong to a larger group of angiogenic genes that are up-regulated under hypoxic conditions. We hypothesized that common genetic variation across other members of this group may also predispose to sporadic ALS. To screen other hypoxia-inducible angiogenic genes for association with SALS, we selected 112 tagging single nucleotide polymorphisms (tgSNPs) that captured the common genetic variation across 16 VEGF-like and eight ANG-like hypoxia-inducible genes. Screening for association was performed in 270 Irish individuals with typical SALS and 272 ethnically matched unrelated controls. SNPs showing association in the Irish phase were genotyped in a replication sample of 281 Swedish sporadic ALS patients and 286 Swedish controls. Seven markers showed association in the Irish. The one modest replication signal observed in the Swedish replication sample, at rs3801158 in the gene inhibin beta A, was for the opposite allele vs. the Irish cohort. We failed to detect association of common variation across 24 candidate hypoxia-inducible angiogenic genes with SALS.

  2. Hypoxia-inducible factor 1α participates in hypoxia-induced epithelial-mesenchymal transition via response gene to complement 32.

    Science.gov (United States)

    Zhu, Liang; Zhao, Qiu

    2017-08-01

    The aim of the present study was to explore the function of response gene to complement 32 (RGC-32) in hypoxia-induced epithelial-mesenchymal transition (EMT) in pancreatic cancer. Three kinds of hypoxia-inducible factor 1α (HIF-1α) small interfering (si)RNA were synthesized and the different effects on the expression of HIF-1α were detected by western blotting. In human pancreatic cancer BxPC-3 cells, HIF-1α levels were diminished using siRNA transfection or HIF-1α inhibitor pretreatment, and the expression levels of RGC-32 and EMT-associated proteins were analyzed using reverse transcription-quantitative polymerase chain reaction and western blotting. Subsequently, the protein levels of epithelial marker, E-cadherin, and mesenchymal marker, vimentin, were determined by western blotting. Results demonstrated that HIF-1α-Homo-488 siRNA and HIF-1α-Homo-1216 siRNA diminished the protein level of HIF-1α. Compared with normoxia, hypoxia induced the levels of HIF-1α, RGC-32, N-cadherin and vimentin, but suppressed the expression of E-cadherin and cytokeratins. The inhibition of HIF-1α by HIF-1α-Homo-1216 siRNA transfection or HIF-1α inhibitor repressed hypoxia-induced HIF-1α, RGC-32, N-cadherin and vimentin, but increased the expression of E-cadherin and cytokeratins. When RGC-32 was knocked down, hypoxia-induced vimentin was suppressed; however, hypoxia-suppressed N-cadherin was released. In conclusion, the present results demonstrated that hypoxia induced the expression of HIF-1α to activate the levels of RGC-32, in turn to regulate the expression EMT-associated proteins for EMT. These findings revealed the function of RGC-32 in hypoxia-induced EMT and may have identified a novel link between HIF-1α and EMT for pancreatic cancer therapy.

  3. Hypoxia-Inducible Regulation of a Prodrug-Activating Enzyme for Tumor-Specific Gene Therapy

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    Toru Shibata

    2002-01-01

    Full Text Available Previous studies have suggested that tumor hypoxia could be exploited for cancer gene therapy. Using hypoxia-responsive elements derived from the human vascular endothelial growth factor gene, we have generated vectors expressing a bacterial nitroreductase. (20NTR gene that can activate the anticancer prodrug CB1954. Stable transfectants of human HT1080 tumor cells with hypoxia-inducible vectors were established with G418 selection. Hypoxic induction of NTR protein correlated with increased sensitivity to in vitro exposure of HT 1080 cells to the prodrug. Growth delay assays were performed with established tumor xenografts derived from the same cells to detect the in vivo efficacy of CB1954 conversion to its cytotoxic form. Significant antitumor effects were achieved with intraperitoneal injections of CB1954 both in tumors that express NTR constitutively or with a hypoxia-inducible promoter. In addition, respiration of 10% O2 increased tumor hypoxia in vivo and enhanced the antitumor effects. Taken together, these results demonstrate that hypoxia-inducible vectors may be useful for tumor-selective gene therapy, although the problem of delivery of the vector to the tumors, particularly to the hypoxic cells in the tumors, is not addressed by these studies.

  4. Identification of crucial microRNAs and genes in hypoxia-induced human lung adenocarcinoma cells

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    Geng Y

    2016-07-01

    Full Text Available Ying Geng,1,* Lili Deng,2,* Dongju Su,1 Jinling Xiao,1 Dongjie Ge,3 Yongxia Bao,1 Hui Jing4 1Department of Respiratory, 2Department of Oncology, The Second Affiliated Hospital of Harbin Medical University, 3Department of Respiratory, The First Hospital of Harbin, 4Department of Emergency, The Second Affiliated Hospital of Harbin Medical University Harbin, Heilongjiang, People’s Republic of China *These authors contributed equally to this work Background: Variations of microRNA (miRNA expression profile in hypoxic lung cancer cells have not been studied so far. Therefore, using miRNA microarray technology, this study aimed to study the miRNA expression profile and investigate the potential crucial miRNAs and their target genes in hypoxia-induced human lung adenocarcinoma cells.Materials and methods: Based on miRNA microarray, miRNA expression profiling of hypoxia-induced lung adenocarcinoma A549 cells was obtained. After identification of differentially expressed miRNAs (DE-miRNAs in hypoxic cells, target genes of DE-miRNAs were predicted, and functional enrichment analysis of targets was conducted. Furthermore, the expression levels of DE-miRNAs and their target genes were validated by real-time quantitative polymerase chain reaction. In addition, using miRNA mimics, the effect of overexpressed DE-miRNAs on A549 cell behaviors (cell proliferation, cell cycle, and apoptosis was evaluated.Results: In total, 14 DE-miRNAs (nine upregulated miRNAs and five downregulated miRNAs were identified in hypoxic cells, compared with normoxic cells. Target genes of both upregulated and downregulated miRNAs were enriched in the functions such as chromatin modification, and pathways such as Wnt signaling pathway and transforming growth factor (TGF-β signaling pathway. The expression levels of several miRNAs and their target genes were confirmed, including hsa-miR-301b/FOXF2, hsa-miR-148b-3p/WNT10B, hsa-miR-769-5p/(SMAD2, ARID1A, and hsa-miR-622. Among them

  5. Identification of hypoxia-induced genes in human SGBS adipocytes by microarray analysis.

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    Kathrin Geiger

    Full Text Available Hypoxia in adipose tissue is suggested to be involved in the development of a chronic mild inflammation, which in obesity can further lead to insulin resistance. The effect of hypoxia on gene expression in adipocytes appears to play a central role in this inflammatory response observed in obesity. However, the global impact of hypoxia on transcriptional changes in human adipocytes is unclear. Therefore, we compared gene expression profiles of human Simpson-Golabi-Behmel syndrome (SGBS adipocytes under normoxic or hypoxic conditions to detect hypoxia-responsive genes in adipocytes by using whole human genome microarrays. Microarray analysis showed more than 500 significantly differentially regulated mRNAs after incubation of the cells under low oxygen levels. To gain further insight into the biological processes, hypoxia-regulated genes after 16 hours of hypoxia were classified according to their function. We identified an enrichment of genes involved in important biological processes such as glycolysis, response to hypoxia, regulation of cellular component movement, response to nutrient levels, regulation of cell migration, and transcription regulator activity. Real-time PCR confirmed eight genes to be consistently upregulated in response to 3, 6 and 16 hours of hypoxia. For adipocytes the hypoxia-induced regulation of these genes is shown here for the first time. Moreover in six of these eight genes we identified HIF response elements in the proximal promoters, specific for the HIF transcription factor family members HIF1A and HIF2A. In the present study, we demonstrated that hypoxia has an extensive effect on gene expression of SGBS adipocytes. In addition, the identified hypoxia-regulated genes are likely involved in the regulation of obesity, the incidence of type 2 diabetes, and the metabolic syndrome.

  6. A preclinical model for noninvasive imaging of hypoxia-induced gene expression; comparison with an exogenous marker of tumor hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Wen Bixiu; Burgman, Paul; Zanzonico, Pat; O' Donoghue, Joseph; Li, Gloria C.; Ling, C. Clifton [Memorial Sloan-Kettering Cancer Center, Department of Medical Physics, New York (United States); Cai Shangde; Finn, Ron [Memorial Sloan-Kettering Cancer Center, Department of Radiology, New York (United States); Serganova, Inna [Memorial Sloan-Kettering Cancer Center, Department of Neurology, New York (United States); Blasberg, Ronald; Gelovani, Juri [Memorial Sloan-Kettering Cancer Center, Department of Radiology, New York (United States); Memorial Sloan-Kettering Cancer Center, Department of Neurology, New York (United States)

    2004-11-01

    Hypoxia is associated with tumor aggressiveness and is an important cause of resistance to radiation therapy and chemotherapy. Assays of tumor hypoxia could provide selection tools for hypoxia-modifying treatments. The purpose of this study was to develop and characterize a rodent tumor model with a reporter gene construct that would be transactivated by the hypoxia-inducible molecular switch, i.e., the upregulation of HIF-1. The reporter gene construct is the herpes simplex virus 1-thymidine kinase (HSV1-tk) fused with the enhanced green fluorescent protein (eGFP) under the regulation of an artificial hypoxia-responsive enhancer/promoter. In this model, tumor hypoxia would up-regulate HIF-1, and through the hypoxia-responsive promoter transactivate the HSV1-tkeGFPfusion gene. The expression of this reporter gene can be assessed with the {sup 124}I-labeled reporter substrate 2'-fluoro-2'-deoxy-1-{beta}-d-arabinofuranosyl-5-iodouracil ({sup 124}I-FIAU), which is phosphorylated by the HSV1-tk enzyme and trapped in the hypoxic cells. Animal positron emission tomography (microPET) and phosphor plate imaging (PPI) were used in this study to visualize the trapped {sup 124}I-FIAU, providing a distribution of the hypoxia-induced molecular events. The distribution of {sup 124}I-FIAU was also compared with that of an exogenous hypoxic cell marker, {sup 18}F-fluoromisonidazole (FMISO). Our results showed that {sup 124}I-FIAU microPET imaging of the hypoxia-induced reporter gene expression is feasible, and that the intratumoral distributions of {sup 124}I-FIAU and {sup 18}F-FMISO are similar. In tumor sections, detailed radioactivity distributions were obtained with PPI which also showed similarity between {sup 124}I-FIAU and {sup 18}F-FMISO. This reporter system is sufficiently sensitive to detect hypoxia-induced transcriptional activation by noninvasive imaging and might provide a valuable tool in studying tumor hypoxia and in validating existing and future

  7. Duplication and diversification of the hypoxia-inducible IGFBP-1 gene in zebrafish

    DEFF Research Database (Denmark)

    Kamei, Hiroyasu; Lu, Ling; Jiao, Shuang

    2008-01-01

    Background: Gene duplication is the primary force of new gene evolution. Deciphering whether a pair of duplicated genes has evolved divergent functions is often challenging. The zebrafish is uniquely positioned to provide insight into the process of functional gene evolution due to its amenability...... to genetic and experimental manipulation and because it possess a large number of duplicated genes. Methodology/Principal Findings: We report the identification and characterization of two hypoxia-inducible genes in zebrafish that are co-ortholgs of human IGF binding protein-1 (IGFBP-1). IGFBP-1...... is a secreted protein that binds to IGF and modulates IGF actions in somatic growth, development, and aging. Like their human and mouse counterparts, in adult zebrafish igfbp-1a and igfbp-1b are exclusively expressed in the liver. During embryogenesis, the two genes are expressed in overlapping spatial domains...

  8. Duplication and diversification of the hypoxia-inducible IGFBP-1 gene in zebrafish.

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    Hiroyasu Kamei

    2008-08-01

    Full Text Available Gene duplication is the primary force of new gene evolution. Deciphering whether a pair of duplicated genes has evolved divergent functions is often challenging. The zebrafish is uniquely positioned to provide insight into the process of functional gene evolution due to its amenability to genetic and experimental manipulation and because it possess a large number of duplicated genes.We report the identification and characterization of two hypoxia-inducible genes in zebrafish that are co-ortholgs of human IGF binding protein-1 (IGFBP-1. IGFBP-1 is a secreted protein that binds to IGF and modulates IGF actions in somatic growth, development, and aging. Like their human and mouse counterparts, in adult zebrafish igfbp-1a and igfbp-1b are exclusively expressed in the liver. During embryogenesis, the two genes are expressed in overlapping spatial domains but with distinct temporal patterns. While zebrafish IGFBP-1a mRNA was easily detected throughout embryogenesis, IGFBP-1b mRNA was detectable only in advanced stages. Hypoxia induces igfbp-1a expression in early embryogenesis, but induces the igfbp-1b expression later in embryogenesis. Both IGFBP-1a and -b are capable of IGF binding, but IGFBP-1b has much lower affinities for IGF-I and -II because of greater dissociation rates. Overexpression of IGFBP-1a and -1b in zebrafish embryos caused significant decreases in growth and developmental rates. When tested in cultured zebrafish embryonic cells, IGFBP-1a and -1b both inhibited IGF-1-induced cell proliferation but the activity of IGFBP-1b was significantly weaker.These results indicate subfunction partitioning of the duplicated IGFBP-1 genes at the levels of gene expression, physiological regulation, protein structure, and biological actions. The duplicated IGFBP-1 may provide additional flexibility in fine-tuning IGF signaling activities under hypoxia and other catabolic conditions.

  9. Identification of functional hypoxia inducible factor response elements in the human lysyl oxidase gene promoter.

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    Wang, Victoria; Davis, David A; Yarchoan, Robert

    2017-08-19

    Human lysyl oxidase (LOX) is a hypoxia-responsive gene whose product catalyzes collagen crosslinking and is thought to be important in cancer metastasis and osteoarthritis. We previously demonstrated that LOX was upregulated by hypoxia inducible factor 2 (HIF-2) more strongly than hypoxia inducible 1 (HIF-1). Here, we further investigated the response of the LOX gene and LOX promoter to HIFs. LOX mRNA, measured by real time reverse transcriptase-PCR, was strongly up-regulated (almost 40-fold), by transfection of HEK-293T cells with a plasmid encoding the HIF-2α subunit of HIF-2, but only three-fold by a plasmid encoding HIF-1α. LOX protein was detectable by Western blot of cells transfected with HIF-2α, but not with HIF-1α. Analysis of a 1487 bp promoter sequence upstream of the human LOX gene revealed 9 potential hypoxia response elements (HREs). Promoter truncation allowed the mapping of two previously unidentified functional HREs, called here HRE8 and HRE7; -455 to -451 and -382 to -386 bp, respectively, upstream of the start codon for LOX. Removal or mutation of these HREs led to a substantial reduction in both HIF-1α and HIF-2α responsiveness. Also, expression of LOX was significantly inhibited by a small molecule specific HIF-2 inhibitor. In conclusion, LOX is highly responsive to HIF-2α and this is largely mediated by two previously unidentified HREs. These observations enhance our understanding of the regulation of this important gene involved in cancer and osteoarthritis, and suggest that these conditions may be targeted by HIF-2 inhibitors. Published by Elsevier Inc.

  10. Fumarate and Succinate Regulate Expression of Hypoxia-inducible Genes via TET Enzymes.

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    Laukka, Tuomas; Mariani, Christopher J; Ihantola, Tuukka; Cao, John Z; Hokkanen, Juho; Kaelin, William G; Godley, Lucy A; Koivunen, Peppi

    2016-02-19

    The TET enzymes are members of the 2-oxoglutarate-dependent dioxygenase family and comprise three isoenzymes in humans: TETs 1-3. These TETs convert 5-methylcytosine to 5-hydroxymethylcytosine (5-hmC) in DNA, and high 5-hmC levels are associated with active transcription. The importance of the balance in these modified cytosines is emphasized by the fact that TET2 is mutated in several human cancers, including myeloid malignancies such as acute myeloid leukemia (AML). We characterize here the kinetic and inhibitory properties of Tets and show that the Km value of Tets 1 and 2 for O2 is 30 μm, indicating that they retain high activity even under hypoxic conditions. The AML-associated mutations in the Fe(2+) and 2-oxoglutarate-binding residues increased the Km values for these factors 30-80-fold and reduced the Vmax values. Fumarate and succinate, which can accumulate to millimolar levels in succinate dehydrogenase and fumarate hydratase-mutant tumors, were identified as potent Tet inhibitors in vitro, with IC50 values ∼400-500 μm. Fumarate and succinate also down-regulated global 5-hmC levels in neuroblastoma cells and the expression levels of some hypoxia-inducible factor (HIF) target genes via TET inhibition, despite simultaneous HIFα stabilization. The combination of fumarate or succinate treatment with TET1 or TET3 silencing caused differential effects on the expression of specific HIF target genes. Altogether these data show that hypoxia-inducible genes are regulated in a multilayered manner that includes epigenetic regulation via TETs and 5-hmC levels in addition to HIF stabilization. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Fumarate and Succinate Regulate Expression of Hypoxia-inducible Genes via TET Enzymes*

    Science.gov (United States)

    Laukka, Tuomas; Mariani, Christopher J.; Ihantola, Tuukka; Cao, John Z.; Hokkanen, Juho; Kaelin, William G.; Godley, Lucy A.; Koivunen, Peppi

    2016-01-01

    The TET enzymes are members of the 2-oxoglutarate-dependent dioxygenase family and comprise three isoenzymes in humans: TETs 1–3. These TETs convert 5-methylcytosine to 5-hydroxymethylcytosine (5-hmC) in DNA, and high 5-hmC levels are associated with active transcription. The importance of the balance in these modified cytosines is emphasized by the fact that TET2 is mutated in several human cancers, including myeloid malignancies such as acute myeloid leukemia (AML). We characterize here the kinetic and inhibitory properties of Tets and show that the Km value of Tets 1 and 2 for O2 is 30 μm, indicating that they retain high activity even under hypoxic conditions. The AML-associated mutations in the Fe2+ and 2-oxoglutarate-binding residues increased the Km values for these factors 30–80-fold and reduced the Vmax values. Fumarate and succinate, which can accumulate to millimolar levels in succinate dehydrogenase and fumarate hydratase-mutant tumors, were identified as potent Tet inhibitors in vitro, with IC50 values ∼400–500 μm. Fumarate and succinate also down-regulated global 5-hmC levels in neuroblastoma cells and the expression levels of some hypoxia-inducible factor (HIF) target genes via TET inhibition, despite simultaneous HIFα stabilization. The combination of fumarate or succinate treatment with TET1 or TET3 silencing caused differential effects on the expression of specific HIF target genes. Altogether these data show that hypoxia-inducible genes are regulated in a multilayered manner that includes epigenetic regulation via TETs and 5-hmC levels in addition to HIF stabilization. PMID:26703470

  12. Myeloid translocation gene-16 co-repressor promotes degradation of hypoxia-inducible factor 1.

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    Parveen Kumar

    Full Text Available The myeloid translocation gene 16 (MTG16 co-repressor down regulates expression of multiple glycolytic genes, which are targets of the hypoxia-inducible factor 1 (HIF1 heterodimer transcription factor that is composed of oxygen-regulated labile HIF1α and stable HIF1β subunits. For this reason, we investigated whether MTG16 might regulate HIF1 negatively contributing to inhibition of glycolysis and stimulation of mitochondrial respiration. A doxycycline Tet-On system was used to control levels of MTG16 in B-lymphoblastic Raji cells. Results from co-association studies revealed MTG16 to interact with HIF1α. The co-association required intact N-terminal MTG16 residues including Nervy Homology Region 1 (NHR1. Furthermore, electrophoretic mobility shift assays demonstrated an association of MTG16 with hypoxia response elements (HREs in PFKFB3, PFKFB4 and PDK1 promoters in-vitro. Results from chromatin immunoprecipitation assays revealed co-occupancy of these and other glycolytic gene promoters by HIF1α, HIF1β and MTG16 in agreement with possible involvement of these proteins in regulation of glycolytic target genes. In addition, MTG16 interacted with prolyl hydroxylase D2 and promoted ubiquitination and proteasomal degradation of HIF1α. Our findings broaden the area of MTG co-repressor functions and reveal MTG16 to be part of a protein complex that controls the levels of HIF1α.

  13. Hypoxia-Inducible Factor Directs POMC Gene to Mediate Hypothalamic Glucose Sensing and Energy Balance Regulation

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    Zhang, Hai; Zhang, Guo; Gonzalez, Frank J.; Park, Sung-min; Cai, Dongsheng

    2011-01-01

    Hypoxia-inducible factor (HIF) is a nuclear transcription factor that responds to environmental and pathological hypoxia to induce metabolic adaptation, vascular growth, and cell survival. Here we found that HIF subunits and HIF2α in particular were normally expressed in the mediobasal hypothalamus of mice. Hypothalamic HIF was up-regulated by glucose to mediate the feeding control of hypothalamic glucose sensing. Two underlying molecular pathways were identified, including suppression of PHDs by glucose metabolites to prevent HIF2α degradation and the recruitment of AMPK and mTOR/S6K to regulate HIF2α protein synthesis. HIF activation was found to directly control the transcription of POMC gene. Genetic approach was then employed to develop conditional knockout mice with HIF inhibition in POMC neurons, revealing that HIF loss-of-function in POMC neurons impaired hypothalamic glucose sensing and caused energy imbalance to promote obesity development. The metabolic effects of HIF in hypothalamic POMC neurons were independent of leptin signaling or pituitary ACTH pathway. Hypothalamic gene delivery of HIF counteracted overeating and obesity under conditions of nutritional excess. In conclusion, HIF controls hypothalamic POMC gene to direct the central nutrient sensing in regulation of energy and body weight balance. PMID:21814490

  14. Anti-vascular agent Combretastatin A-4-P modulates Hypoxia Inducible Factor-1 and gene expression

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    Currie Margaret J

    2006-12-01

    Full Text Available Abstract Background A functional vascular network is essential for the survival, growth and spread of solid tumours, making blood vessels a key target for therapeutic strategies. Combretastatin A-4 phosphate (CA-4-P is a tubulin-depolymerising agent in Phase II clinical trials as a vascular disrupting agent. Not much is known of the molecular effect of CA-4-P under tumour conditions. The tumour microenvironment differs markedly from that in normal tissue, specifically with respect to oxygenation (hypoxia. Gene regulation under tumour conditions is governed by hypoxia inducible factor 1 (HIF-1, controlling angiogenic and metastatic pathways. Methods We investigated the effect of CA-4-P on factors of the upstream and downstream signalling pathway of HIF-1 in vitro. Results CA-4-P treatment under hypoxia tended to reduce HIF-1 accumulation in a concentration-dependent manner, an effect which was more prominent in endothelial cells than in cancer cell lines. Conversely, CA-4-P increased HIF-1 accumulation under aerobic conditions in vitro. At these concentrations of CA-4-P under aerobic conditions, nuclear factor κB was activated via the small GTPase RhoA, and expression of the HIF-1 downstream angiogenic effector gene, vascular endothelial growth factor (VEGF-A, was increased. Conclusion Our findings advance the understanding of signal transduction pathways involved in the actions of the anti-vascular agent CA-4-P.

  15. Integrative genomics reveals hypoxia inducible genes that are associated with a poor prognosis in neuroblastoma patients

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    Kao, Clara; Hernandez, Kyle M.; DeWane, Gillian; Salwen, Helen R.; Chlenski, Alexandre; Dobratic, Marija; Mariani, Christopher J.; Godley, Lucy A.; Prabhakar, Nanduri; White, Kevin; Stranger, Barbara E.; Cohn, Susan L.

    2016-01-01

    Neuroblastoma is notable for its broad spectrum of clinical behavior ranging from spontaneous regression to rapidly progressive disease. Hypoxia is well known to confer a more aggressive phenotype in neuroblastoma. We analyzed transcriptome data from diagnostic neuroblastoma tumors and hypoxic neuroblastoma cell lines to identify genes whose expression levels correlate with poor patient outcome and are involved in the hypoxia response. By integrating a diverse set of transcriptome datasets, including those from neuroblastoma patients and neuroblastoma derived cell lines, we identified nine genes (SLCO4A1, ENO1, HK2, PGK1, MTFP1, HILPDA, VKORC1, TPI1, and HIST1H1C) that are up-regulated in hypoxia and whose expression levels are correlated with poor patient outcome in three independent neuroblastoma cohorts. Analysis of 5-hydroxymethylcytosine and ENCODE data indicate that at least five of these nine genes have an increase in 5-hydroxymethylcytosine and a more open chromatin structure in hypoxia versus normoxia and are putative targets of hypoxia inducible factor (HIF) as they contain HIF binding sites in their regulatory regions. Four of these genes are key components of the glycolytic pathway and another three are directly involved in cellular metabolism. We experimentally validated our computational findings demonstrating that seven of the nine genes are significantly up-regulated in response to hypoxia in the four neuroblastoma cell lines tested. This compact and robustly validated group of genes, is associated with the hypoxia response in aggressive neuroblastoma and may represent a novel target for biomarker and therapeutic development. PMID:27765905

  16. Hypoxia-inducible factors - regulation, role and comparative aspects in tumourigenesis

    DEFF Research Database (Denmark)

    Hansen, A E; Kristensen, A T; Law, I

    2011-01-01

    Hypoxia-inducible factors (HIFs) play a key role in the cellular response experienced in hypoxic tumours, mediating adaptive responses that allow hypoxic cells to survive in the hostile environment. Identification and understanding of tumour hypoxia and the influence on cellular processes carries...

  17. Gene Therapy by Targeted Adenovirus-mediated Knockdown of Pulmonary Endothelial Tph1 Attenuates Hypoxia-induced Pulmonary Hypertension

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    Morecroft, Ian; White, Katie; Caruso, Paola; Nilsen, Margaret; Loughlin, Lynn; Alba, Raul; Reynolds, Paul N; Danilov, Sergei M; Baker, Andrew H; MacLean, Margaret R

    2012-01-01

    Serotonin is produced by pulmonary arterial endothelial cells (PAEC) via tryptophan hydroxylase-1 (Tph1). Pathologically, serotonin acts on underlying pulmonary arterial cells, contributing to vascular remodeling associated with pulmonary arterial hypertension (PAH). The effects of hypoxia on PAEC-Tph1 activity are unknown. We investigated the potential of a gene therapy approach to PAH using selective inhibition of PAEC-Tph1 in vivo in a hypoxic model of PAH. We exposed cultured bovine pulmonary arterial smooth muscle cells (bPASMCs) to conditioned media from human PAECs (hPAECs) before and after hypoxic exposure. Serotonin levels were increased in hypoxic PAEC media. Conditioned media evoked bPASMC proliferation, which was greater with hypoxic PAEC media, via a serotonin-dependent mechanism. In vivo, adenoviral vectors targeted to PAECs (utilizing bispecific antibody to angiotensin-converting enzyme (ACE) as the selective targeting system) were used to deliver small hairpin Tph1 RNA sequences in rats. Hypoxic rats developed PAH and increased lung Tph1. PAEC-Tph1 expression and development of PAH were attenuated by our PAEC-Tph1 gene knockdown strategy. These results demonstrate that hypoxia induces Tph1 activity and selective knockdown of PAEC-Tph1 attenuates hypoxia-induced PAH in rats. Further investigation of pulmonary endothelial-specific Tph1 inhibition via gene interventions is warranted. PMID:22525513

  18. Altered expression of hypoxia-inducible factor-1α (HIF-1α and its regulatory genes in gastric cancer tissues.

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    Jihan Wang

    Full Text Available Tissue hypoxia induces reprogramming of cell metabolism and may result in normal cell transformation and cancer progression. Hypoxia-inducible factor 1-alpha (HIF-1α, the key transcription factor, plays an important role in gastric cancer development and progression. This study aimed to investigate the underlying regulatory signaling pathway in gastric cancer using gastric cancer tissue specimens. The integration of gene expression profile and transcriptional regulatory element database (TRED was pursued to identify HIF-1α ↔ NFκB1 → BRCA1 → STAT3 ← STAT1 gene pathways and their regulated genes. The data showed that there were 82 differentially expressed genes that could be regulated by these five transcription factors in gastric cancer tissues and these genes formed 95 regulation modes, among which seven genes (MMP1, TIMP1, TLR2, FCGR3A, IRF1, FAS, and TFF3 were hub molecules that are regulated at least by two of these five transcription factors simultaneously and were associated with hypoxia, inflammation, and immune disorder. Real-Time PCR and western blot showed increasing of HIF-1α in mRNA and protein levels as well as TIMP1, TFF3 in mRNA levels in gastric cancer tissues. The data are the first study to demonstrate HIF-1α-regulated transcription factors and their corresponding network genes in gastric cancer. Further study with a larger sample size and more functional experiments is needed to confirm these data and then translate into clinical biomarker discovery and treatment strategy for gastric cancer.

  19. Recombinant AAV-PR39-mediated hypoxia-inducible factor 1α gene expression attenuates myocardial infarction.

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    Sun, Lijun; Hao, Yuewen; Nie, Xiaowei; Xu, Jian; Li, Zhenwu; Zhang, Wei; Liu, Ying; Zhang, Xuexin

    2014-01-01

    PR39 is an angiogenic masterswitch protein, belonging to the second generation of angiogenic growth factors. However, the role of recombinant adeno-associated virus (AAV) carrying the PR39 fusion gene (AAV-PR39) in acute myocardial infarction remains unclear. Therefore, in this study, we investigated the role of AAV-PR39 in an experimental animal model of acute myocardial infarction. The PR39 gene was fused with the transmembrane peptide, TAT, 6xHis‑tag and NT4 signal sequences. AAV-PR39 was then obtained by calcium phosphate co-precipitation. A total of 18 healthy Chinese mini pigs were randomly divided into an experimental groups (the AAV-PR39-treated group) and a control group [phosphated-buffered saline (PBS)-treated group]. Following the induction of myocardial infarction, enhanced 3.0T MR imaging was performed to observe the changes in myocardial signal intensity at 0 h, 1, 2 and 3 weeks. The expression of hypoxia-inducible factor‑1α (HIF-1α) in the myocardial tissues was determined by SABC immunohistochemistry. In addition, in vitro experiments using CRL-1730 endothelial cells transfected with AAV vector containing NT4-TAT-His-PR39 revealed that the AAV-PR39-treated group had a significantly higher expression of HIF-1α compared with the control group. Moreover, PR39 regulated the HIF-1α-induced expression of angiogenic growth factors. Under hypoxic conditions, the anti-apoptotic effects in the AAV-PR39 group were more pronounced than those observed in the control (PBS-treated) group. In vivo, the enforced expression of recombinant PR39 elevated the level of HIF-1α under hypoxic conditions and decreased the size of the infarcted areas by upregulating the expression of HIF-1α in the areas surrounding the infarct area. Taken together, our data demonstrate that the recombinant AAV-PR39-mediated HIF-1α expression attenuates myocardial infarction, indicating that AAV-PR39 may serve as a novel therapeutic agent for the treatment of myocardial infarction.

  20. Vascular endothelial growth factor and hypoxia-inducible factor-1α gene polymorphisms and coronary collateral formation in patients with coronary chronic total occlusions

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    Vincent Amoah

    2016-06-01

    Full Text Available Introduction: We evaluated the association between two single nucleotide polymorphisms of the vascular endothelial growth factor gene and one of the hypoxia-inducible factor-1α gene and the degree of coronary collateral formation in patients with a coronary chronic total occlusion. Methods: Totally, 98 patients with symptomatic coronary artery disease and a chronic total occlusion observed during coronary angiography were recruited. Genotyping of two vascular endothelial growth factor promoter single nucleotide polymorphisms (−152G>A and −165C>T and the C1772T single nucleotide polymorphism of hypoxia-inducible factor-1α were performed using polymerase chain reaction and restriction fragment length polymorphism analysis. The presence and extent of collateral vessel filling was scored by blinded observers using the Rentrop grade. Results: We found no association between the vascular endothelial growth factor −152G>A, −165C>T and hypoxia-inducible factor-1α −1772C>T with the presence and filling of coronary collateral vessels. A history of percutaneous coronary intervention and transient ischaemic attack/cerebrovascular accident were associated with the presence of enhanced collateral vessel formation following binary logistic regression analysis. Conclusion: The study findings suggest that coronary collateral formation is not associated with the tested polymorphic variants of vascular endothelial growth factor and hypoxia-inducible factor-1α in patients with symptomatic coronary artery disease and the presence of a chronic total occlusion.

  1. Cross-talk between constitutive androstane receptor and hypoxia-inducible factor in the regulation of gene expression.

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    Shizu, Ryota; Shindo, Sawako; Yoshida, Takemi; Numazawa, Satoshi

    2013-05-23

    Hypoxia inducible factor (HIF) and 5'-AMP-activated protein kinase are often activated under similar physiological conditions. Constitutive androstane receptor (CAR) translocates into the nucleus in accordance with 5'-AMP-activated protein kinase and thus confers transactivation. The aim of the present study was to investigate a possible link between CAR and HIFα. Phenobarbital (PB), a typical CAR activator, increased the gene expression of HIF-target genes in the livers of mice, including erythropoietin, heme oxygenase-1 and vascular endothelial growth factor-a. PB induced an accumulation of nuclear HIF-1α and an increase in the HIF-responsive element-mediated transactivation in HepG2 cells. Cobalt chloride, a typical HIF activator, induced the gene expression of CAR-target genes, including cyp2b9 and cyp2b10, an accumulation of nuclear CAR and an increase in the PB-responsive enhancer module-mediated transactivation in the mouse liver. Immunoprecipitation-immunoblot and chromatin immunoprecipitation analyses suggest that CAR binds to the PB-responsive enhancer module with HIF-1α in the liver of untreated mice and that the complex dissociates upon PB treatment. Taken together these results suggest that CAR and HIF-α interact and reciprocally modulate the functions of each other. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  2. Gene expression profiling of fixed tissues identified hypoxia-inducible factor-1α, VEGF, and matrix metalloproteinase-2 as biomarkers of lymph node metastasis in hepatocellular carcinoma.

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    Xiang, Zuo-Lin; Zeng, Zhao-Chong; Fan, Jia; Tang, Zhao-You; Zeng, Hai-Ying; Gao, Dong-Mei

    2011-08-15

    Hepatocellular carcinoma (HCC) most often develops in patients infected with hepatitis B or hepatitis C virus. Differential gene expression profiling is useful for investigating genes associated with lymph node metastasis (LNM). We screened genes to identify potential biomarkers for LNM in HCC. RNA was extracted from formalin-fixed specimens of paired intratumoral and peritumoral tissues of patients with lymph node-positive (n = 36) or negative (n = 36) HCC. A cDNA-mediated annealing, selection, extension, and ligation assay was done with an array of 502 known cancer-related genes to identify differentially expressed genes in 20 pairs of patients with or without LNM. Candidate biomarkers were evaluated by using immunohistochemistry and tissue microarrays in an independent cohort of 309 HCC patients who had undergone hepatectomy. Of the 309 patients, 235 (76.1%) patients were infected with hepatitis B. Compared with lymph node-negative patients, lymph node-positive patients had 17 overexpressed genes and 19 underexpressed genes in intratumoral tissues, and 25 overexpressed genes and 22 underexpressed genes in peritumoral tissues. Hypoxia-inducible factor (HIF)-1α, VEGF, and matrix metalloproteinase (MMP)-2 were selected for analysis in the cohort of 309 HCC patients. We found that intratumoral protein levels of HIF-1α, VEGF, and MMP-2 were independent risk factors for developing LNM. We identified 83 cancer genes that were differentially expressed in lymph node-positive and lymph node-negative HCC. Our findings show that the combination of intratumoral HIF-1α, VEGF, and MMP-2 may be useful as a molecular prediction model for LNM. ©2011 AACR.

  3. Chenodeoxycholic Acid Reduces Hypoxia Inducible Factor-1α Protein and Its Target Genes.

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    Yunwon Moon

    Full Text Available This study evaluated HIF-1α inhibitors under different hypoxic conditions, physiological hypoxia (5% O2 and severe hypoxia (0.1% O2. We found that chenodeoxy cholic acid (CDCA reduced the amount of HIF-1α protein only under physiological hypoxia but not under severe hypoxia without decreasing its mRNA level. By using a proteasome inhibitor MG132 and a translation inhibitor cyclohexamide, we showed that CDCA reduced HIF-1α protein by decreasing its translation but not by enhancing its degradation. The following findings indicated that farnesoid X receptor (FXR, a CDCA receptor and its target gene, Small heterodimer partner (SHP are not involved in this effect of CDCA. Distinctly from CDCA, MG132 prevented SHP and an exogenous FXR agonist, GW4064 from reducing HIF-1α protein. Furthermore a FXR antagonist, guggulsterone failed to prevent CDCA from decreasing HIF-1α protein. Furthermore, guggulsterone by itself reduced HIF-1α protein even in the presence of MG132. These findings suggested that CDCA and guggulsterone reduced the translation of HIF-1α in a mechanism which FXR and SHP are not involved. This study reveals novel therapeutic functions of traditional nontoxic drugs, CDCA and guggulsterone, as inhibitors of HIF-1α protein.

  4. Hypoxia-Inducible Hydrogels

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    Park, Kyung Min; Gerecht, Sharon

    2014-01-01

    Oxygen is vital for the existence of all multicellular organisms, acting as a signaling molecule regulating cellular activities. Specifically, hypoxia, which occurs when the partial pressure of oxygen falls below 5%, plays a pivotal role during development, regeneration, and cancer. Here we report a novel hypoxia-inducible (HI) hydrogel composed of gelatin and ferulic acid that can form hydrogel networks via oxygen consumption in a laccase-mediated reaction. Oxygen levels and gradients within the hydrogels can be accurately controlled and precisely predicted. We demonstrate that HI hydrogels guide vascular morphogenesis in vitro via hypoxia-inducible factors activation of matrix metalloproteinases and promote rapid neovascularization from the host tissue during subcutaneous wound healing. The HI hydrogel is a new class of biomaterials that may prove useful in many applications, ranging from fundamental studies of developmental, regenerative and disease processes through the engineering of healthy and diseased tissue models towards the treatment of hypoxia-regulated disorders. PMID:24909742

  5. Loss of the Birt-Hogg-Dubé gene product folliculin induces longevity in a hypoxia-inducible factor-dependent manner.

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    Gharbi, Hakam; Fabretti, Francesca; Bharill, Puneet; Rinschen, Markus M; Brinkkötter, Sibylle; Frommolt, Peter; Burst, Volker; Schermer, Bernhard; Benzing, Thomas; Müller, Roman-Ulrich

    2013-08-01

    Signaling through the hypoxia-inducible factor hif-1 controls longevity, metabolism, and stress resistance in Caenorhabditis elegans. Hypoxia-inducible factor (HIF) protein levels are regulated through an evolutionarily conserved ubiquitin ligase complex. Mutations in the VHL gene, encoding a core component of this complex, cause a multitumor syndrome and renal cell carcinoma in humans. In the nematode, deficiency in vhl-1 promotes longevity mediated through HIF-1 stabilization. However, this longevity assurance pathway is not yet understood. Here, we identify folliculin (FLCN) as a novel interactor of the hif-1/vhl-1 longevity pathway. FLCN mutations cause Birt-Hogg-Dubé syndrome in humans, another tumor syndrome with renal tumorigenesis reminiscent of the VHL disease. Loss of the C. elegans ortholog of FLCN F22D3.2 significantly increased lifespan and enhanced stress resistance in a hif-1-dependent manner. F22D3.2, vhl-1, and hif-1 control longevity by a mechanism distinct from insulin-like signaling. Daf-16 deficiency did not abrogate the increase in lifespan mediated by flcn-1. These findings define FLCN as a player in HIF-dependent longevity signaling and connect organismal aging, stress resistance, and regulation of longevity with the formation of renal cell carcinoma. © 2013 John Wiley & Sons Ltd and the Anatomical Society.

  6. [Experimental approach to the gene therapy of motor neuron disease with the use of genes hypoxia-inducible factors].

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    Ismailov, Sh M; Barykova, Iu A; Shmarov, M M; Tarantul, V Z; Barskov, I V; Kucherianu, V G; Brylev, L V; Logunov, D Iu; Tutykhina, I L; Bocharov, E V; Zakharova, M N; Naroditskiĭ, B S; Illarioshkin, S N

    2014-05-01

    Motor neuron disease (MND), or amyotrophic lateral sclerosis, is a fatal neurodegenerative disorder characterized by a progressive loss of motor neurons in the spinal cord and the brain. Several angiogenic and neurogenic growth factors, such as the vascular endothelial growth factor (VEGF), angiogenin (ANG), insulin-like growth factor (IGF) and others, have been shown to promote survival of the spinal motor neurons during ischemia. We constructed recombinant vectors using human adenovirus 5 (Ad5) carrying the VEGF, ANG or IGF genes under the control of the cytomegalovirus promoter. As a model for MND, we employed a transgenic mice strain, B6SJL-Tg (SOD1*G93A)d11 Gur/J that develops a progressive degeneration of the spinal motor neurons caused by the expression of a mutated Cu/Zn superoxide dismutase gene SOD1. Delivery of the therapeutic genes to the spinal motor neurons was done using the effect of the retrograde axonal transport after multiple injections of the Ad5-VEGF, Ad5-ANG and Ad5-IGF vectors and their combinations into the limbs and back muscles of the SOD1(G93A) mice. Viral transgene expression in the spinal cord motor neurons was confirmed by immunocytochemistry and RT-RCR. We assessed the neurological status, motor activity and lifespan of experimental and control animal groups. We discovered that SOD1(G93A) mice injected with the Ad5-VEGF + Ad5-ANG combination showed a 2-3 week delay in manifestation of the disease, higher motor activity at the advanced stages of the disease, and at least a 10% increase in the lifespan compared to the control and other experimental groups. These results support the safety and therapeutic efficacy of the tested recombinant treatment. We propose that the developed experimental MND treatment based on viral delivery of VEGF + ANG can be used as a basis for gene therapy drug development and testing in the preclinical and clinical trials of the MND.

  7. MUC1, a new hypoxia inducible factor target gene, is an actor in clear renal cell carcinoma tumor progression.

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    Aubert, Sébastien; Fauquette, Valérie; Hémon, Brigitte; Lepoivre, Réjane; Briez, Nicolas; Bernard, David; Van Seuningen, Isabelle; Leroy, Xavier; Perrais, Michaël

    2009-07-15

    The hypoxia inducible factor (HIF) signaling pathway is known as the main renal carcinogenetic pathway. MUC1, an O-glycoprotein membrane-bound mucin, is overexpressed in clear renal cell carcinomas (cRCC) with correlation to two major prognostic factors: tumor-node-metastasis stage and nuclear Fürhman grade. We questioned whether there is a direct link between the HIF pathway and MUC1 overexpression in renal tumors. Interestingly, we observed concomitant increase of HIF-1alpha and MUC1 in metastatic cRCC group versus nonmetastatic cRCC group. Using different renal cell models and small interfering RNA assays targeting either HIF-1alpha or YC-1, a HIF-1 pharmacologic inhibitor, we showed induction of MUC1 expression under hypoxia by a HIF-dependent mechanism. Chromatin immunoprecipitation assay showed a direct binding of HIF-1alpha at the MUC1 promoter. In addition, combined site-directed mutagenesis and gel shift assay allowed the identification of two functional putative hypoxia responsive elements at -1488/-1485 and at -1510/-1507 in the promoter. Using a rat kidney model of ischemia/reperfusion, we confirmed in vivo that clamping renal pedicle for 1 hour followed by 2 hours of reperfusion induced increased MUC1 expression. Furthermore, MUC1 knockdown induced significant reduction of invasive and migration properties of renal cancer cells under hypoxia. Altogether, these results show that MUC1 is directly regulated by HIF-1alpha and affects the invasive and migration properties of renal cancer cells. Thus, MUC1 could serve as a potential therapeutic target in cRCC.

  8. Overexpression and Knockdown of Hypoxia-Inducible Factor 1 Disrupt the Expression of Steroidogenic Enzyme Genes and Early Embryonic Development in Zebrafish

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    Tianfeng Tan

    2017-06-01

    Full Text Available Hypoxia is an important environmental stressor leading to endocrine disruption and reproductive impairment in fish. Although the hypoxia-inducible factor 1 (HIF-1 is known to regulate the transcription of various genes mediating oxygen homeostasis, its role in modulating steroidogenesis-related gene expression remains poorly understood. In this study, the regulatory effect of HIF-1 on the expression of 9 steroidogenic enzyme genes was investigated in zebrafish embryos using a “gain-of-function and loss-of-function” approach. Eight of the genes, CYP11a, CYP11b2, 3β-HSD, HMGCR, CYP17a1, 17β-HSD2, CYP19a , and CYP19b , were found to be differentially upregulated at 24 and 48 hpf following zHIF-1α-ΔODD overexpression (a mutant zebrafish HIF-1α protein with proline-414 and proline-557 deleted. Knockdown of zHIF-1α also affected the expression pattern of the steroidogenic enzyme genes. Overexpression of zHIF-1α and hypoxia exposure resulted in downregulated StAR expression but upregulated CYP11a and 3β-HSD expression in zebrafish embryos. Conversely, the expression patterns of these 3 genes were reversed in embryos in which zHIF-1α was knocked down under normoxia, suggesting that these 3 genes are regulated by HIF-1. Overall, the findings from this study indicate that HIF-1–mediated mechanisms are likely involved in the regulation of specific steroidogenic genes.

  9. Suppression of hypoxia-inducible factor-1alpha and its downstream genes reduces acute hyperglycemia-enhanced hemorrhagic transformation in a rat model of cerebral ischemia.

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    Chen, Chunhua; Ostrowski, Robert P; Zhou, Changman; Tang, Jiping; Zhang, John H

    2010-07-01

    We evaluated a role of hypoxia-inducible factor-1alpha (HIF-1alpha) and its downstream genes in acute hyperglycemia-induced hemorrhagic transformation in a rat model of focal cerebral ischemia. Male Sprague-Dawley rats weighing 280-300 g (n = 105) were divided into sham, 90 min middle cerebral artery occlusion (MCAO), MCAO plus HIF-1alpha inhibitors, 2-methoxyestradiol (2ME2) or 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1), groups. Rats received an injection of 50% dextrose (6 ml/kg intraperitoneally) at 15 min before MCAO. HIF-1alpha inhibitors were administered at the onset of reperfusion. The animals were examined for neurological deficits and sacrificed at 6, 12, 24, and 72 hr following MCAO. The cerebral tissues were collected for histology, zymography, and Western blot analysis. The expression of HIF-1alpha was increased in ischemic brain tissues after MCAO and reduced by HIF-1alpha inhibitors. In addition, 2ME2 reduced the expression of vascular endothelial growth factor (VEGF) and the elevation of active matrix metalloproteinase-2 and -9 (MMP-2/MMP-9) in the ipsilateral hemisphere. Both 2ME2 and YC-1 reduced infarct volume and ameliorated neurological deficits. However, only 2ME2 attenuated hemorrhagic transformation in the ischemic territory. In conclusion, the inhibition of HIF-1alpha and its downstream genes attenuates hemorrhagic conversion of cerebral infarction and ameliorates neurological deficits after focal cerebral ischemia.

  10. Human adipocytes are highly sensitive to intermittent hypoxia induced NF-kappaB activity and subsequent inflammatory gene expression

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    Taylor, Cormac T. [School of Medicine and Medical Science, The Conway Institute, University College Dublin (Ireland); Kent, Brian D.; Crinion, Sophie J.; McNicholas, Walter T. [School of Medicine and Medical Science, The Conway Institute, University College Dublin (Ireland); Pulmonary and Sleep Disorders Unit, St. Vincent’s University Hospital, Dublin (Ireland); Ryan, Silke, E-mail: silke.ryan@ucd.ie [School of Medicine and Medical Science, The Conway Institute, University College Dublin (Ireland); Pulmonary and Sleep Disorders Unit, St. Vincent’s University Hospital, Dublin (Ireland)

    2014-05-16

    Highlights: • Intermittent hypoxia (IH) leads to NF-κB activation in human primary adipocytes. • Adipocytes bear higher pro-inflammatory potential than other human primary cells. • IH leads to upregulation of multiple pro-inflammatory genes in human adipocytes. - Abstract: Introduction: Intermittent hypoxia (IH)-induced activation of pro-inflammatory pathways is a major contributing factor to the cardiovascular pathophysiology associated with obstructive sleep apnea (OSA). Obesity is commonly associated with OSA although it remains unknown whether adipose tissue is a major source of inflammatory mediators in response to IH. The aim of this study was to test the hypothesis that IH leads to augmented inflammatory responses in human adipocytes when compared to cells of non-adipocyte lineages. Methods and results: Human primary subcutaneous and visceral adipocytes, human primary microvascular pulmonary endothelial cells (HUMEC-L) and human primary small airway epithelial cells (SAEC) were exposed to 0, 6 or 12 cycles of IH or stimulated with tumor necrosis factor (TNF)-α. IH led to a robust increase in NF-κB DNA-binding activity in adipocytes compared with normoxic controls regardless of whether the source of adipocytes was visceral or subcutaneous. Notably, the NF-κB response of adipocytes to both IH and TNF-α was significantly greater than that in HUMEC-L and SAEC. Western blotting confirmed enhanced nuclear translocation of p65 in adipocytes in response to IH, accompanied by phosphorylation of I-κB. Parallel to p65 activation, we observed a significant increase in secretion of the adipokines interleukin (IL)-8, IL-6 and TNF-α with IH in adipocytes accompanied by significant upregulation of mRNA expression. PCR-array suggested profound influence of IH on pro-inflammatory gene expression in adipocytes. Conclusion: Human adipocytes demonstrate strong sensitivity to inflammatory gene expression in response to acute IH and hence, adipose tissue may be a key

  11. [Silencing hypoxia inducible factor-2α gene by small interference RNA inhibits the growth of mammosphere cells in nude mice under hypoxic microenvironment].

    Science.gov (United States)

    Qu, Hong-bo; Fan, Yuan-ming; Han, Ming-li; Zeng, Ni; Zhu, Zhi-kun; Liu, Hong; Xie, Jia; Wu, Cheng-yi; Tang, Wei-xue

    2013-04-16

    To explore the effects of silencing hypoxia inducible factor-2α (HIF-2α) by small interference RNA on the growth of mammosphere cells in nude mice under hypoxic microenvironment. The empty and interference vectors were transfected into MCF-7 cell. Then G418 was added to screen the positive cells to obtain stable cell line. The empty and interference vectors were inoculated subcutaneously into left and right back near hind limb of nude mice. The volume and weight of tumors were calculated respectively. The expressions of HIF-2α, CD44, OCT-4 and KLF-4 protein in xenograft tumor tissues were detected by Western blot. The expression vector of HIF-2α-siRNA was successfully established. The formation of mammosphere was lowered by silencing HIF-2α gene expression. In contract to empty vector group cell, there were obvious decreases in the volumes and weights of tumors in interference group (P interference group (0.42 ± 0.01) was much lower than that of the empty vector group (0.89 ± 0.03, P interference group (0.21 ± 0.01) was much lower than the empty vector group (0.78 ± 0.03, P interference group (0.42 ± 0.01)was much lower than the empty vector group (0.68 ± 0.03, P interference group (0.34 ± 0.01) was much lower than the empty vector group (0.72 ± 0.03, P < 0.05). Silencing HIF-2α gene can effectively inhibit the growth of breast cancer stem cells in nude mice under hypoxic microenvironment. Its mechanism may be through inhibited capacity for self-renewal and proliferation of breast cancer stem cells in vivo through the down-regulated expressions of markers associated with stem cells. HIF-2α is expected to become a new target for gene therapy of breast cancer.

  12. Gene therapy with an erythropoietin enhancer-mediated, hypoxia-inducible gene expression system in the corpus cavernosum of mice with high-cholesterol diet-induced erectile dysfunction.

    Science.gov (United States)

    Ryu, Ji-Kan; Lee, Minhyung; Choi, Min Ji; Kim, Hyun Ah; Jin, Hai-Rong; Kim, Woo Jean; Yin, Guo Nan; Song, Kang-Moon; Kwon, Mi-Hye; Suh, Jun-Kyu

    2012-01-01

    Cavernous hypoxia is an important factor in the pathogenesis of vasculogenic erectile dysfunction (ED). Therefore, the hypoxia-inducible gene expression system can be exploited as gene therapy for vasculogenic ED. This study was undertaken to examine the effectiveness of a hypoxia-inducible gene expression system, namely, the RTP801 promoter or the erythropoietin enhancer, in a mouse model of hypercholesterolemic ED in vivo and in primary cultured mouse cavernous endothelial cells in vitro. Two-month-old male C57BL/6 mice were fed a diet containing 4% cholesterol and 1% cholic acid, and age-matched control animals were fed a normal diet for 3 months. Mouse cavernous endothelial cells were isolated and cultured under normoxic or hypoxic conditions. After treatment of animals or endothelial cells with pSV-Luc, pRTP801-Luc, or pEpo-SV-Luc vector, gene expression was evaluated by luciferase assay, and the gene expression area was evaluated by immunohistochemistry. Plasmids pRTP801-Luc and pEpo-SV-Luc induced gene expression significantly in the hypercholesterolemic mice and in cavernous endothelial cells under hypoxia, and the highest gene expression was noted in the group treated with pEpo-SV-Luc. Gene expression was higher for more than 7 days in the hypercholesterolemic mice injected with pEpo-SV-Luc than in mice injected with pSV-Luc. As shown by immunohistochemistry, the gene expression area was also greater in the pEpo-SV-Luc group than in the pSV-Luc group, but the difference was not as great as that in luciferase activity. The hypoxia-specific gene expression system could be a valuable tool for facilitating gene delivery into ischemic corpus cavernosum tissue resulting from vascular causes.

  13. Myeloid cell leukemia-1 (Mc1-1 is a candidate target gene of hypoxia-inducible factor-1 (HIF-1 in the testis

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    Palladino Michael A

    2012-12-01

    Full Text Available Abstract Background Spermatic cord torsion can lead to testis ischemia (I and subsequent ischemia-reperfusion (I/R causing germ cell-specific apoptosis. Previously, we demonstrated that the hypoxia-inducible factor-1 (HIF-1 transcription factor, a key regulator of physiological responses to hypoxia, is abundant in Leydig cells in normoxic and ischemic testes. We hypothesize that testicular HIF-1 activates the expression of antiapoptotic target genes to protect Leydig cells from apoptosis. In silico analysis of testis genes containing a consensus hypoxia response element (HRE, 5’-RCGTG-3’ identified myeloid cell leukemia-1 (Mcl-1 as a potential HIF-1 target gene. The purpose of this study was to determine whether HIF-1 shows DNA-binding activity in normoxic and ischemic testes and whether Mcl-1 is a target gene of testicular HIF-1. Methods The testicular HIF-1 DNA-binding capacity was analyzed in vitro using a quantitative enzyme-linked immunosorbent assay (ELISA and electrophoretic mobility shift assays (EMSA. MCL-1 protein expression was evaluated by immunoblot analysis and immunohistochemistry. The binding of testicular HIF-1 to the Mcl-1 gene was examined via chromatin immunoprecipitation (ChIP analysis. Results The ELISA and EMSA assays demonstrated that testicular HIF-1 from normoxic and ischemic testes binds DNA equally strongly, suggesting physiological roles for HIF-1 in the normoxic testis, unlike most tissues in which HIF-1 is degraded under normoxic conditions and is only activated by hypoxia. MCL-1 protein was determined to be abundant in both normoxic and ischemic testes and expressed in Leydig cells. In a pattern identical to that of HIF-1 expression, the steady-state levels of MCL-1 were not significantly affected by I or I/R and MCL-1 co-localized with HIF-1α in Leydig cells. Chromatin immunoprecipitation (ChIP analysis using a HIF-1 antibody revealed sequences enriched for the Mcl-1 promoter. Conclusions The results

  14. The Mycobacterium tuberculosis Clp gene regulator is required for in vitro reactivation from hypoxia-induced dormancy.

    Science.gov (United States)

    McGillivray, Amanda; Golden, Nadia A; Kaushal, Deepak

    2015-01-23

    Mycobacterium tuberculosis (Mtb) is the leading cause of death from an infectious disease worldwide and is the causative agent of tuberculosis (Chao, M. C., and Rubin, E. J. (2010) Annu. Rev. Microbiol. 64, 293-311). Throughout infection, Mtb encounters a variety of host pressures. Thus, responding to these host stresses via the induction of multiple regulatory networks is needed for survival within the host. The Clp protease gene regulator, Rv2745c (clgR), is induced in response to environmental stress conditions, implicating its potential role in Mtb pathogenesis. Transcriptional activation of genes downstream of Rv2745c occurs in a condition-dependent manner. Our isogenic Mtb:ΔRv2745c mutant expresses a significantly different phenotype upon reaeration conditions. Transcriptional analysis revealed differential gene expression profiles relative to wild-type Mtb. Rv2745c is strongly induced in response to hypoxic and reaeration conditions, implicating a role of Rv2745c in vivo during both establishment of infection and reactivation. We found dysregulation of downstream genes within both the σ(H)/σ(E) regulon as well as the dosR regulon in the isogenic mutant, Mtb:ΔRv2745c. Upon hypoxic and reaeration conditions, Clp protease induction occurred within wild-type Mtb, indicating that activation of clgR, which subsequently leads to Clp protease induction, is crucial for degradation of misfolded proteins and ultimately survival of Mtb upon specific stress conditions. Our data indicate the diverse response of Rv2745c, σ(H) and σ(E) in response to a variety of stress conditions. Activation of Rv2745c in response to various stress conditions leads to differential activation of downstream genes, indicating the diverse role of Rv2745c and its importance for Mtb survival in vivo. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Antiapoptotic Effect of Gene Therapy with Recombinant Adenovirus Vector Containing Hypoxia-inducible Factor-1α after Cerebral Ischemia and Reperfusion in Rats

    Science.gov (United States)

    Yang, Ming-Lang; Tao, Tao; Xu, Jian; Liu, Zhi; Xu, Dan

    2017-01-01

    Background: Mounting evidence has demonstrated that hypoxia-inducible factor-1α (HIF-1α) could attenuate brain injuries after cerebral ischemia and reperfusion (CIR). However, few reports have addressed the therapeutic efficacies of a recombinant adenovirus vector containing HIF-1α (AdHIF-1α) gene after ischemia and reperfusion. The aim of this study was to examine the antiapoptotic and neuroprotective effects of AdHIF-1α gene for cerebral injuries after ischemia and reperfusion in rats. Methods: From February to December 2016, male Sprague-Dawley rats were randomly divided into normal, sham, CIR, AdHIF-1α, and recombinant adenovirus (Ad) groups. Middle cerebral artery occlusion model was established by Longa's method and reperfusion resumed at 2 h postocclusion. AdHIF-1α solution, Ad solution, and phosphate-buffered saline were injected into the right lateral ventricle of rats in AdHIF-1α, Ad, and CIR groups. Brain tissue sections were observed under fluorescent microscope to confirm the definite expression of recombinant adenovirus in Ad and AdHIF-1α groups. The expressions of HIF-1α protein were analyzed by immunohistochemical staining at 6 h, 24 h, and 72 h postreperfusion. Brain water content and neurological deficit scores were evaluated at 6 h, 24 h, and 72 h postreperfusion. Pathological brain injuries were examined after hematoxylin and eosin stain and nerve cell apoptosis was measured after terminal-deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) stain at 72 h postreperfusion. Comparisons were conducted with one-way analysis of variance by post hoc Scheffe's test among different experimental groups. Results: Green fluorescent protein was successfully expressed in brain tissue of Ad and AdHIF-1α groups from 24 h to 21 days postinjection. As detected by immunohistochemical staining, the expressions of HIF-1α protein were obviously enhanced in AdHIF-1α group than those in CIR and Ad groups at 24 h and 72 h

  16. Gene transcripts encoding hypoxia-inducible factor (HIF) exhibit tissue- and muscle fiber type-dependent responses to hypoxia and hypercapnic hypoxia in the Atlantic blue crab, Callinectes sapidus.

    Science.gov (United States)

    Hardy, Kristin M; Follett, Chandler R; Burnett, Louis E; Lema, Sean C

    2012-09-01

    Hypoxia inducible factor (HIF) is a transcription factor that under low environmental oxygen regulates the expression of suites of genes involved in metabolism, angiogenesis, erythropoiesis, immune function, and growth. Here, we isolated and sequenced partial cDNAs encoding hif-α and arnt/hif-β from the Atlantic blue crab, Callinectes sapidus, an estuarine species that frequently encounters concurrent hypoxia (low O(2)) and hypercapnia (elevated CO(2)). We then examined the effects of acute exposure (1h) to hypoxia (H) and hypercapnic hypoxia (HH) on relative transcript abundance for hif-α and arnt/hif-β in different tissues (glycolytic muscle, oxidative muscle, hepatopancreas, gill, and gonads) using quantitative real-time RT-PCR. Our results indicate that hif-α and arnt/hif-β mRNAs were constitutively present under well-aerated normoxia (N) conditions in all tissues examined. Further, H and HH exposure resulted in both tissue-specific and muscle fiber type-specific effects on relative hif-α transcript abundance. In the gill and glycolytic muscle, relative hif-α mRNA levels were significantly lower under H and HH, compared to N, while no change (or a slight increase) was detected in oxidative muscle, hepatopancreas and gonadal tissues. H and HH did not affect relative transcript abundance for arnt/hif-β in any tissue or muscle fiber type. Thus, in crustaceans the HIF response to H and HH appears to involve changes in hif transcript abundance, with variation in hif-α and arnt/hif-β transcriptional dynamics occurring in both a tissue- and muscle fiber type-dependent manner. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. RIG-I Resists Hypoxia-Induced Immunosuppression and Dedifferentiation.

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    Engel, Christina; Brügmann, Grethe; Lambing, Silke; Mühlenbeck, Larissa H; Marx, Samira; Hagen, Christian; Horváth, Dorottya; Goldeck, Marion; Ludwig, Janos; Herzner, Anna-Maria; Drijfhout, Jan W; Wenzel, Daniela; Coch, Christoph; Tüting, Thomas; Schlee, Martin; Hornung, Veit; Hartmann, Gunther; Van den Boorn, Jasper G

    2017-06-01

    A hypoxic tumor microenvironment is linked to poor prognosis. It promotes tumor cell dedifferentiation and metastasis and desensitizes tumor cells to type-I IFN, chemotherapy, and irradiation. The cytoplasmic immunoreceptor retinoic acid-inducible gene-I (RIG-I) is ubiquitously expressed in tumor cells and upon activation by 5'-triphosphate RNA (3pRNA) drives the induction of type I IFN and immunogenic cell death. Here, we analyzed the impact of hypoxia on the expression of RIG-I in various human and murine tumor and nonmalignant cell types and further investigated its function in hypoxic murine melanoma. 3pRNA-inducible RIG-I-expression was reduced in hypoxic melanoma cells compared with normoxic controls, a phenomenon that depended on the hypoxia-associated transcription factor HIF1α. Still, RIG-I functionality was conserved in hypoxic melanoma cells, whereas responsiveness to recombinant type-I IFN was abolished, due to hypoxia-induced loss of type I IFN receptor expression. Likewise, RIG-I activation in hypoxic melanoma cells, but not exposure to recombinant IFNα, provoked melanocyte antigen-specific CD8+ T-cell and NK-cell attack. Scavenging of hypoxia-induced reactive oxygen species by vitamin C restored the inducible expression of RIG-I under hypoxia in vitro, boosted in vitro anti-melanoma NK- and CD8+ T-cell attack, and augmented 3pRNA antitumor efficacy in vivo These results demonstrate that RIG-I remains operational under hypoxia and that RIG-I function is largely insensitive to lower cell surface expression of the IFNα receptor. RIG-I function could be fortified under hypoxia by the combined use of 3pRNA with antioxidants. Cancer Immunol Res; 5(6); 455-67. ©2017 AACR. ©2017 American Association for Cancer Research.

  18. Hypobaric intermittent hypoxia attenuates hypoxia-induced depressor response.

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    Fang Cui

    Full Text Available Hypobaric intermittent hypoxia (HIH produces many favorable effects in the cardiovascular system such as anti-hypertensive effect. In this study, we showed that HIH significantly attenuated a depressor response induced by acute hypoxia.Sprague-Dawley rats received HIH in a hypobaric chamber simulating an altitude of 5000 m. The artery blood pressure (ABP, heart rate (HR and renal sympathetic nerve activity (RSNA were recorded in anesthetized control rats and rats received HIH. The baseline ABP, HR and RSNA were not different between HIH and control rats. Acute hypoxia-induced decrease in ABP was significantly attenuated in HIH rat compared with control rats. However, acute hypoxia-induced increases in HR and RSNA were greater in HIH rat than in control rats. After removal of bilateral ascending depressor nerves, acute hypoxia-induced depressor and sympathoexcitatory responses were comparable in control and HIH rats. Furthermore, acute hypoxia-induced depressor and sympathoexcitatory responses did not differ between control and HIH groups after blocking ATP-dependent K(+ channels by glibenclamide. The baroreflex function evaluated by intravenous injection of phenylephrine and sodium nitroprusside was markedly augmented in HIH rats compared with control rats. The pressor and sympathoexcitatory responses evoked by intravenous injection of cyanide potassium were also significantly greater in HIH rats than in control rats.Our findings suggest that HIH suppresses acute hypoxia-induced depressor response through enhancement of baroreflex and chemoreflex function, which involves activation of ATP-dependent K(+ channels. This study provides new information and underlying mechanism on the beneficiary effect of HIH on maintaining cardiovascular homeostasis.

  19. siRNA Screening Identifies the Host Hexokinase 2 (HK2) Gene as an Important Hypoxia-Inducible Transcription Factor 1 (HIF-1) Target Gene in Toxoplasma gondii-Infected Cells.

    Science.gov (United States)

    Menendez, Matthew T; Teygong, Crystal; Wade, Kristin; Florimond, Celia; Blader, Ira J

    2015-06-23

    Although it is established that oxygen availability regulates cellular metabolism and growth, little is known regarding how intracellular pathogens use host factors to grow at physiological oxygen levels. Therefore, large-scale human small interfering RNA screening was performed to identify host genes important for growth of the intracellular protozoan parasite Toxoplasma gondii at tissue oxygen tensions. Among the genes identified by this screen, we focused on the hexokinase 2 (HK2) gene because its expression is regulated by hypoxia-inducible transcription factor 1 (HIF-1), which is important for Toxoplasma growth. Toxoplasma increases host HK2 transcript and protein levels in a HIF-1-dependent manner. In addition, parasite growth at 3% oxygen is restored in HIF-1-deficient cells transfected with HK2 expression plasmids. Both HIF-1 activation and HK2 expression were accompanied by increases in host glycolytic flux, suggesting that enhanced HK2 expression in parasite-infected cells is functionally significant. Parasite dependence on host HK2 and HIF-1 expression is not restricted to transformed cell lines, as both are required for parasite growth in nontransformed C2C12 myoblasts and HK2 is upregulated in vivo following infection. While HK2 is normally associated with the cytoplasmic face of the outer mitochondrial membrane at physiological O2 levels, HK2 relocalizes to the host cytoplasm following infection, a process that is required for parasite growth at 3% oxygen. Taken together, our findings show that HIF-1-dependent expression and relocalization of HK2 represent a novel mechanism by which Toxoplasma establishes its replicative niche at tissue oxygen tensions. Little is known regarding how the host cell contributes to the survival of the intracellular parasite Toxoplasma gondii at oxygen levels that mimic those found in tissues. Our previous work showed that Toxoplasma activates the expression of an oxygen-regulated transcription factor that is required for

  20. Polymorphic variation of hypoxia inducible factor-1 A (HIF1A) gene might contribute to the development of knee osteoarthritis: a pilot study.

    Science.gov (United States)

    Fernández-Torres, Javier; Hernández-Díaz, Cristina; Espinosa-Morales, Rolando; Camacho-Galindo, Javier; Galindo-Sevilla, Norma del Carmen; López-Macay, Ámbar; Zamudio-Cuevas, Yessica; Martínez-Flores, Karina; Santamaría-Olmedo, Mónica Guadalupe; Pineda, Carlos; Granados, Julio; Martínez-Nava, Gabriela Angélica; Gutiérrez, Marwin; López-Reyes, Alberto G

    2015-08-21

    Osteoarthritis (OA) is a multifactorial degenerative condition of the whole joint with a complex pathogenesis whose development and progression is significantly mediated by interactions between the joint cartilage and articular tissues, particularly, proinflammatory mediators and oxidative stress, which results in cartilage deterioration and subchondral bone destruction. HIF-1 alpha regulates oxygen homeostasis in hypoxic tissues such as joint cartilage; efficiency of transcriptional activity of the HIF1A gene is strongly influenced by the presence of polymorphic variants. Given the loss of articular cartilage and with intention to restore damaged tissue, WISP-1 participates in the development of subchondral bone; further, its expression is highly increased in chondrocytes of OA patients. The aim of this study was to evaluate gene frequencies of HIF1A and WISP1 polymorphisms in Mexican patients suffering from knee OA. We determined HIF1A rs11549465 (P582S), rs11549467 (A588T), and rs2057482 (C191T), and WISP1 rs2929970 (A2364G) polymorphisms in 70 Mexican patients with knee OA and compare them to those present in 66 ethnically matched healthy controls. Genotyping for these polymorphisms was performed by Real-Time PCR using TaqMan probes. Gene frequencies exhibited a significant increase of the CC genotype of rs11549465 polymorphism in knee OA patients as compared with those present in controls (P = 0.003 OR = 5.7, 95% CI = 1.7-21.6); CT genotype and T allele showed decreased frequency in the knee OA group vs. the controls (P = 0.003 OR = 0.2, CI = 0.05-0.6; and P = 0.004 OR = 0.2, CI = 0.05-0.65, respectively). Allele frequencies of the other polymorphic variants were similar in both patients and controls. These results suggest that the presence of the rs11549465 SNP (HIF1A) plays a role protective in the loss of articular cartilage in our population, and offers the possibility to further study the molecular mechanisms within

  1. Chronic Normobaric Hypoxia Induces Pulmonary Hypertension in Rats: Role of NF-κB.

    Science.gov (United States)

    Fan, Junming; Fan, Xiaofang; Li, Yang; Ding, Lu; Zheng, Qingqing; Guo, Jinbin; Xia, Dongmei; Xue, Feng; Wang, Yongyu; Liu, Shufang; Gong, Yongsheng

    2016-03-01

    To investigate whether nuclear factor-kappa B (NF-κB) activation is involved in chronic normobaric hypoxia-induced pulmonary hypertension (PH), rats were treated with saline or an NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC, 150 mg/kg, sc, twice daily), and exposed to normoxia or chronic normobaric hypoxia with a fraction of inspired oxygen of ∼0.1 for 14 days. Lung tissue levels of NF-κB activity, and interleukin (IL)-1β, IL-6, and cyclooxygenase-2 mRNAs, were determined, and mean pulmonary arterial pressure, right ventricular hypertrophy, and right heart function were evaluated. Compared to the normoxia exposure group, rats exposed to chronic normobaric hypoxia showed an increased NF-κB activity, measured by increased nuclear translocation of p50 and p65 proteins, an increased inflammatory gene expression in the lungs, elevated mean pulmonary arterial blood pressure and mean right ventricular pressure, right ventricular hypertrophy, as assessed by right ventricle-to-left ventricle plus septum weight ratio, and right heart dysfunction. Treatment of hypoxia-exposed rats with PDTC inhibited NF-κB activity, decreased pulmonary arterial blood pressure and right ventricular pressure, and ameliorated right ventricular hypertrophy and right heart dysfunction. Hypoxia exposure increased protein kinase C activity and promoted pulmonary artery smooth muscle cell proliferation in vitro. Our data suggest that NF-κB activation may contribute to chronic normobaric hypoxia-induced PH.

  2. Hypoxia-inducible factor-1α plays roles in Epstein-Barr virus's natural life cycle and tumorigenesis by inducing lytic infection through direct binding to the immediate-early BZLF1 gene promoter.

    Directory of Open Access Journals (Sweden)

    Richard J Kraus

    2017-06-01

    Full Text Available When confronted with poor oxygenation, cells adapt by activating survival signaling pathways, including the oxygen-sensitive transcriptional regulators called hypoxia-inducible factor alphas (HIF-αs. We report here that HIF-1α also regulates the life cycle of Epstein-Barr virus (EBV. Incubation of EBV-positive gastric carcinoma AGS-Akata and SNU-719 and Burkitt lymphoma Sal and KemIII cell lines with a prolyl hydroxylase inhibitor, L-mimosine or deferoxamine, or the NEDDylation inhibitor MLN4924 promoted rapid and sustained accumulation of both HIF-1α and lytic EBV antigens. ShRNA knockdown of HIF-1α significantly reduced deferoxamine-mediated lytic reactivation. HIF-1α directly bound the promoter of the EBV primary latent-lytic switch BZLF1 gene, Zp, activating transcription via a consensus hypoxia-response element (HRE located at nt -83 through -76 relative to the transcription initiation site. HIF-1α did not activate transcription from the other EBV immediate-early gene, BRLF1. Importantly, expression of HIF-1α induced EBV lytic-gene expression in cells harboring wild-type EBV, but not in cells infected with variants containing base-pair substitution mutations within this HRE. Human oral keratinocyte (NOK and gingival epithelial (hGET cells induced to differentiate by incubation with either methyl cellulose or growth in organotypic culture accumulated both HIF-1α and Blimp-1α, another cellular factor implicated in lytic reactivation. HIF-1α activity also accumulated along with Blimp-1α during B-cell differentiation into plasma cells. Furthermore, most BZLF1-expressing cells observed in lymphomas induced by EBV in NSG mice with a humanized immune system were located distal to blood vessels in hypoxic regions of the tumors. Thus, we conclude that HIF-1α plays central roles in both EBV's natural life cycle and EBV-associated tumorigenesis. We propose that drugs that induce HIF-1α protein accumulation are good candidates for

  3. Hypoxia-inducible factor-1α plays roles in Epstein-Barr virus’s natural life cycle and tumorigenesis by inducing lytic infection through direct binding to the immediate-early BZLF1 gene promoter

    Science.gov (United States)

    Kraus, Richard J.; Cordes, Blue-leaf A.; Nawandar, Dhananjay M.; Ma, Shidong; McChesney, Kyle G.; Lin, Zhen; Makielski, Kathleen R.; Lee, Denis L.; Lambert, Paul F.; Johannsen, Eric C.; Kenney, Shannon C.

    2017-01-01

    When confronted with poor oxygenation, cells adapt by activating survival signaling pathways, including the oxygen-sensitive transcriptional regulators called hypoxia-inducible factor alphas (HIF-αs). We report here that HIF-1α also regulates the life cycle of Epstein-Barr virus (EBV). Incubation of EBV-positive gastric carcinoma AGS-Akata and SNU-719 and Burkitt lymphoma Sal and KemIII cell lines with a prolyl hydroxylase inhibitor, L-mimosine or deferoxamine, or the NEDDylation inhibitor MLN4924 promoted rapid and sustained accumulation of both HIF-1α and lytic EBV antigens. ShRNA knockdown of HIF-1α significantly reduced deferoxamine-mediated lytic reactivation. HIF-1α directly bound the promoter of the EBV primary latent-lytic switch BZLF1 gene, Zp, activating transcription via a consensus hypoxia-response element (HRE) located at nt -83 through -76 relative to the transcription initiation site. HIF-1α did not activate transcription from the other EBV immediate-early gene, BRLF1. Importantly, expression of HIF-1α induced EBV lytic-gene expression in cells harboring wild-type EBV, but not in cells infected with variants containing base-pair substitution mutations within this HRE. Human oral keratinocyte (NOK) and gingival epithelial (hGET) cells induced to differentiate by incubation with either methyl cellulose or growth in organotypic culture accumulated both HIF-1α and Blimp-1α, another cellular factor implicated in lytic reactivation. HIF-1α activity also accumulated along with Blimp-1α during B-cell differentiation into plasma cells. Furthermore, most BZLF1-expressing cells observed in lymphomas induced by EBV in NSG mice with a humanized immune system were located distal to blood vessels in hypoxic regions of the tumors. Thus, we conclude that HIF-1α plays central roles in both EBV’s natural life cycle and EBV-associated tumorigenesis. We propose that drugs that induce HIF-1α protein accumulation are good candidates for development of a

  4. Functional pathway mapping analysis for hypoxia-inducible factors.

    Science.gov (United States)

    Chuang, Chia-Sheng; Pai, Tun-Wen; Hu, Chin-Hua; Tzou, Wen-Shyong; Dah-Tsyr Chang, Margaret; Chang, Hao-Teng; Chen, Chih-Chia

    2011-06-20

    Hypoxia-inducible factors (HIFs) are transcription factors that play a crucial role in response to hypoxic stress in living organisms. The HIF pathway is activated by changes in cellular oxygen levels and has significant impacts on the regulation of gene expression patterns in cancer cells. Identifying functional conservation across species and discovering conserved regulatory motifs can facilitate the selection of reference species for empirical tests. This paper describes a cross-species functional pathway mapping strategy based on evidence of homologous relationships that employs matrix-based searching techniques for identifying transcription factor-binding sites on all retrieved HIF target genes. HIF-related orthologous and paralogous genes were mapped onto the conserved pathways to indicate functional conservation across species. Quantitatively measured HIF pathways are depicted in order to illustrate the extent of functional conservation. The results show that in spite of the evolutionary process of speciation, distantly related species may exhibit functional conservation owing to conservative pathways. The novel terms OrthRate and ParaRate are proposed to quantitatively indicate the flexibility of a homologous pathway and reveal the alternative regulation of functional genes. The developed functional pathway mapping strategy provides a bioinformatics approach for constructing biological pathways by highlighting the homologous relationships between various model species. The mapped HIF pathways were quantitatively illustrated and evaluated by statistically analyzing their conserved transcription factor-binding elements. hypoxia-inducible factor (HIF), hypoxia-response element (HRE), transcription factor (TF), transcription factor binding site (TFBS), KEGG (Kyoto Encyclopedia of Genes and Genomes), cross-species comparison, orthology, paralogy, functional pathway.

  5. Inhibition of Hypoxia Inducible Factor Alpha and Astrocyte-Elevated Gene-1 Mediates Cryptotanshinone Exerted Antitumor Activity in Hypoxic PC-3 Cells

    Directory of Open Access Journals (Sweden)

    Hyo-Jeong Lee

    2012-01-01

    Full Text Available Although cryptotanshinone (CT was known to exert antitumor activity in several cancers, its molecular mechanism under hypoxia still remains unclear. Here, the roles of AEG-1 and HIF-1α in CT-induced antitumor activity were investigated in hypoxic PC-3 cells. CT exerted cytotoxicity against prostate cancer cells and suppressed HIF-1α accumulation and AEG-1 expression in hypoxic PC-3 cells. Also, AEG-1 was overexpressed in prostate cancer cells. Interestingly, HIF-1α siRNA transfection enhanced the cleavages of caspase-9,3, and PAPR and decreased expression of Bcl-2 and AEG1 induced by CT in hypoxic PC-3 cells. Of note, DMOG enhanced the stability of AEG-1 and HIF-1α during hypoxia. Additionally, CT significantly reduced cellular level of VEGF in PC-3 cells and disturbed tube formation of HUVECs. Consistently, ChIP assay revealed that CT inhibited the binding of HIF-1α to VEGF promoter. Furthermore, CT at 10 mg/kg suppressed the growth of PC-3 cells in BALB/c athymic nude mice by 46.4% compared to untreated control. Consistently, immunohistochemistry revealed decreased expression of Ki-67, CD34, VEGF, carbonic anhydrase IX, and AEG-1 indices in CT-treated group compared to untreated control. Overall, our findings suggest that CT exerts antitumor activity via inhibition of HIF-1α, AEG1, and VEGF as a potent chemotherapeutic agent.

  6. Modulation of Hypoxia-Induced Pulmonary Vascular Leakage in Rats by Seabuckthorn (Hippophae rhamnoides L.

    Directory of Open Access Journals (Sweden)

    Jayamurthy Purushothaman

    2011-01-01

    Full Text Available Cerebral and pulmonary syndromes may develop in unacclimatized individuals shortly after ascent to high altitude resulting in high altitude illness, which may occur due to extravasation of fluid from intra to extravascular space in the brain, lungs and peripheral tissues. The objective of the present study was to evaluate the potential of seabuckthorn (SBT (Hippophae rhamnoides L. leaf extract (LE in curtailing hypoxia-induced transvascular permeability in the lungs by measuring lung water content, leakage of fluorescein dye into the lungs and further confirmation by quantitation of albumin and protein in the bronchoalveolar lavage fluid (BALF. Exposure of rats to hypoxia caused a significant increase in the transvascular leakage in the lungs. The SBT LE treated animals showed a significant decrease in hypoxia-induced vascular permeability evidenced by decreased water content and fluorescein leakage in the lungs and decreased albumin and protein content in the BALF. The SBT extract was also able to significantly attenuate hypoxia-induced increase in the levels of proinflammatory cytokines and decrease hypoxia-induced oxidative stress by stabilizing the levels of reduced glutathione and antioxidant enzymes. Pretreatment of the extract also resulted in a significant decrease in the circulatory catecholamines and significant increase in the vasorelaxation of the pulmonary arterial rings as compared with the controls. Further, the extract significantly attenuated hypoxia-induced increase in the VEGF levels in the plasma, BALF (ELISA and lungs (immunohistochemistry. These observations suggest that SBT LE is able to provide significant protection against hypoxia-induced pulmonary vascular leakage.

  7. Association of thymidylate synthase and hypoxia inducible factor-1alpha DNA polymorphisms with pancreatic cancer.

    Science.gov (United States)

    Ruiz-Tovar, Jaime; Fernandez-Contreras, Maria Encarnación; Martín-Perez, Elena; Gamallo, Carlos

    2012-01-01

    Thymidylate synthase and hypoxia inducible factor-1α play a central role in the control of tumor progression. In the present study, we investigated the effect of three DNA polymorphisms within the thymidylate synthase gene and two within hypoxia inducible factor-1α on the prognosis of pancreatic cancer. A retrospective study was performed in 59 patients diagnosed with invasive ductal adenocarcinoma of the pancreas and 159 healthy volunteers. The studied DNA polymorphisms were a variable tandem repeat of 28 bp (rs45445694), a G/C single nucleotide polymorphism (rs34743033), and a deletion of 6 bp (ins1494del 6bp; rs34489327) within the thymidylate synthase gene and C1772T and G1790A single nucleotide polymorphisms within hypoxia inducible factor-1α (rs11549465 and rs11549467, respectively) . Variable tandem repeats were determined by specific polymerase chain reaction, whereas thymidylate synthase single nucleotide polymorphism G/C, ins1494del 6pb, and hypoxia inducible factor-1α polymorphisms were identified by polymerase chain reaction and RFLP. Thymidylate synthase and hypoxia inducible factor-1α genotype distributions in patients and healthy volunteers were determined. The impact of the polymorphisms on clinico-pathological variables, including survival, was also studied. The frequency of carriers of the variant del6bp allele was significantly higher among patients (70.0% vs 51.0% of healthy donors, P = 0.02); 42% of male patients were homozygous 2R/2R vs 13.6% of females (P = 0.03), but differences regarding gender were not observed among healthy volunteers. Concerning hypoxia inducible factor-1α C1772T and G1790A single nucleotide polymorphisms, the rates of variant T/T and A/A homozygous genotypes were significantly elevated among patients (18.6% vs 5.3%, P = 0.001, and 5.1% vs none, P = 0.021 respectively). In our study, the variant del14946bp allele within the thymidylate synthase gene, and TT and AA genotypes of C1772T and G1790A hypoxia inducible

  8. Central role of T helper 17 cells in chronic hypoxia-induced pulmonary hypertension.

    Science.gov (United States)

    Maston, Levi D; Jones, David T; Giermakowska, Wieslawa; Howard, Tamara A; Cannon, Judy L; Wang, Wei; Wei, Yongyi; Xuan, Weimin; Resta, Thomas C; Gonzalez Bosc, Laura V

    2017-05-01

    Inflammation is a prominent pathological feature in pulmonary arterial hypertension, as demonstrated by pulmonary vascular infiltration of inflammatory cells, including T and B lymphocytes. However, the contribution of the adaptive immune system is not well characterized in pulmonary hypertension caused by chronic hypoxia. CD4+ T cells are required for initiating and maintaining inflammation, suggesting that these cells could play an important role in the pathogenesis of hypoxic pulmonary hypertension. Our objective was to test the hypothesis that CD4+ T cells, specifically the T helper 17 subset, contribute to chronic hypoxia-induced pulmonary hypertension. We compared indices of pulmonary hypertension resulting from chronic hypoxia (3 wk) in wild-type mice and recombination-activating gene 1 knockout mice (RAG1-/-, lacking mature T and B cells). Separate sets of mice were adoptively transferred with CD4+, CD8+, or T helper 17 cells before normoxic or chronic hypoxic exposure to evaluate the involvement of specific T cell subsets. RAG1-/- mice had diminished right ventricular systolic pressure and arterial remodeling compared with wild-type mice exposed to chronic hypoxia. Adoptive transfer of CD4+ but not CD8+ T cells restored the hypertensive phenotype in RAG1-/- mice. Interestingly, RAG1-/- mice receiving T helper 17 cells displayed evidence of pulmonary hypertension independent of chronic hypoxia. Supporting our hypothesis, depletion of CD4+ cells or treatment with SR1001, an inhibitor of T helper 17 cell development, prevented increased pressure and remodeling responses to chronic hypoxia. We conclude that T helper 17 cells play a key role in the development of chronic hypoxia-induced pulmonary hypertension. Copyright © 2017 the American Physiological Society.

  9. Clinical Aspects of Hypoxia-inducible Factors in Colorectal Cancer

    DEFF Research Database (Denmark)

    Havelund, Birgitte Mayland; Spindler, Karen-Lise Garm; Sørensen, Flemming Brandt

    2010-01-01

    Clinical Aspects of Hypoxia-inducible Factors in Colorectal Cancer  Birgitte Mayland Havelund1,4 MD, Karen-Lise Garm Spindler1,4 MD, PhD, Flemming Brandt Sørensen2,4 MD, DMSc, Ivan Brandslund3 MD, DMSc, Anders Jakobsen1,4 MD, DMSc.1Department of Oncology, 2Pathology and 3Biochemistry, Vejle...... activates transcription of numerous genes associated with angiogenesis, ATP-metabolism, cell-proliferation, glycolysis and apoptosis. HIF-1α is over expressed in many malignant tumors and is reported to play an important role in tumor invasion and progression. The aim of this Ph.D. project is to investigate...... with locally advanced rectal cancer, treated with preoperative chemoradiation (CRT).Preliminary ResultsExpression of HIF-1α has been investigated in diagnostic biopsies from 58 rectal tumors who received preoperative long-course CRT. An association was found between major response to CRT as measured by tumor...

  10. Lysyl oxidase mediates hypoxia-induced radioresistance in non-small cell lung cancer A549 cells.

    Science.gov (United States)

    Gong, Chongwen; Gu, Runxia; Jin, Honglin; Sun, Yao; Li, Zhenyu; Chen, Jing; Wu, Gang

    2016-02-01

    Hypoxia-induced radioresistance has been well known as the main obstacle in cancer radiotherapy. Lysyl oxidase (LOX) was previously demonstrated to play an important role in hypoxia-induced biological behaviors, such as metastasis and angiogenesis, through hypoxia-inducible factor-1α (HIF-1α), which is an important contributing factor to radioresistance in tumor cells. However, how LOX plays a role in hypoxia-induced radioresistance has yet to be determined. Here, we found that LOX expression was in accordance with HIF-1α expression, and LOX expression at the mRNA and protein level, and enzymatic activity were remarkably upregulated in the hypoxic A549 cells, compared with normoxic A549 cells. Inhibition of LOX resulted in the reduction of the ability to repair double-stranded breaks (DSBs), promotion of apoptosis, relief of G2/M cycle arrest, and eventually reduction of hypoxia-induced radioresistance in the hypoxic A549 cells. This suggests that LOX may play an important role in hypoxia-induced radioresistance. Together, our results might suggest a novel potential therapeutic target in the management of non-small cell lung cancer (NSCLC). © 2016 by the Society for Experimental Biology and Medicine.

  11. HIF1 Contributes to Hypoxia-Induced Pancreatic Cancer Cells Invasion via Promoting QSOX1 Expression

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    Chen-Ye Shi

    2013-08-01

    Full Text Available Background: Quiescin sulfhydryl oxidase 1 (QSOX1, which oxidizes sulfhydryl groups to form disulfide bonds in proteins, is found to be over-expressed in various pancreatic cancer cell lines and patients. QSOX1 promotes invasion of pancreatic cancer cells by activating MMP-2 and MMP-9. However, its regulatory mechanism remains largely undefined. Methods: Real-time PCR and Western blot were employed to detect the expression of QSOX1 in human pancreatic cancer cell lines under hypoxic condition. Luciferase reporter and ChIP assays were used to assess the regulation of QSOX1 by hypoxia-inducible factor 1 (HIF-1. Small interfering RNA (siRNA was applied to knock down endogenous expression of QSOX1. Matrigel-coated invasion chamber essays were conducted to detect the invasion capacity of QSOX1-depleted cells. Results: Both hypoxia and hypoxia mimicking reagent up-regulated the expression of QSOX1 in human pancreatic cancer cell lines. Knockdown of HIF-1α eliminated hypoxia induced QSOX1 expression. HIF-1α was found directly bound to two hypoxia-response elements (HRE of QSOX1 gene, both of which were required for HIF-1 induced QSOX1 expression. Moreover, QSOX1 silencing blocked hypoxia-induced pancreatic cancer cells invasion. Conclusion: QSOX1 is a direct target of HIF-1 and may contribute to hypoxia-induced pancreatic cancer cells invasion.

  12. Reactive oxygen species (ROS) and the heat stress response of Daphnia pulex: ROS-mediated activation of hypoxia-inducible factor 1 (HIF-1) and heat shock factor 1 (HSF-1) and the clustered expression of stress genes.

    Science.gov (United States)

    Klumpen, Eva; Hoffschröer, Nadine; Zeis, Bettina; Gigengack, Ulrike; Dohmen, Elias; Paul, Rüdiger J

    2017-01-01

    Heat stress in ectotherms involves direct (e.g. protein damage) and/or indirect effects (temperature-induced hypoxia and ROS formation), which cause activation of the transcription factors (TF) heat shock factor 1 (HSF-1) and/or hypoxia-inducible factor 1 (HIF-1). The present study focused on the links between stress (ROS) signals, nuclear (n) and cytoplasmic (c) HSF-1/HIF-1 levels, and stress gene expression on mRNA and protein levels (e.g. heat-shock protein 90, HSP90) upon acute heat and ROS (H2 O2 ) stress. Acute heat stress (30°C) evoked fluctuations in ROS level. Different feeding regimens, which affected the glutathione (GSH) level, allowed altering the frequency of ROS fluctuations. Other data showed fluctuation frequency to depend also on ROS production rate. The heat-induced slow or fast ROS fluctuations (at high or low GSH levels) evoked slow or fast fluctuations in the levels of nHIF-1α, nHSF-1 and gene products (mRNAs and protein), albeit after different time delays. Time delays to ROS fluctuations were, for example,shorter for nHIF-1α than for nHSF-1 fluctuations, and nHIF-1α fluctuations preceded and nHSF-1 fluctuations followed fluctuations in HSP90 mRNA level. Cytoplasmic TF levels either changed little (cHIF-1α) or showed a steady increase (cHSF-1). Applying acute H2 O2 stress (at 20°C) revealed effects on nHIF-1α and mRNA levels, but no significant effects on nHSF-1 level. Transcriptome data additionally showed coordinated fluctuations of mRNA levels upon acute heat stress, involving mRNAs for HSPs and other stress proteins, with all corresponding genes carrying DNA binding motifs for HIF-1 and HSF-1. This study provided evidence for promoting effects of ROS and HIF-1 on early haemoglobin, HIF-1α and HSP90 mRNA expressions upon heat or ROS stress. The increasing cHSF-1 level likely affected nHSF-1 level and later HSP90 mRNA expression. Heat stress evoked ROS fluctuations, with this stress signal forwarded via nHIF-1 and nHSF-1

  13. Quantifying circulating hypoxia-induced RNA transcripts in maternal blood to determine in utero fetal hypoxic status.

    Science.gov (United States)

    Whitehead, Clare; Teh, Wan Tinn; Walker, Susan P; Leung, Cheryl; Mendis, Sonali; Larmour, Luke; Tong, Stephen

    2013-12-09

    Hypoxia in utero can lead to stillbirth and severe perinatal injury. While current prenatal tests can identify fetuses that are hypoxic, none can determine the severity of hypoxia/acidemia. We hypothesized a hypoxic/acidemic fetus would up-regulate and release hypoxia-induced mRNA from the fetoplacental unit into the maternal circulation, where they can be sampled and quantified. Furthermore, we hypothesized the abundance of hypoxia induced mRNA in the maternal circulation would correlate with severity of fetal hypoxia/acidemia in utero. We therefore examined whether abundance of hypoxia-induced mRNA in the maternal circulation correlates with the degree of fetal hypoxia in utero. We performed a prospective study of two cohorts: 1) longitudinal study of pregnant women undergoing an induction of labor (labor induces acute fetal hypoxia) and 2) pregnancies complicated by severe preterm growth restriction (chronic fetal hypoxia). For each cohort, we correlated hypoxia induced mRNA in the maternal blood with degree of fetal hypoxia during its final moments in utero, evidenced by umbilical artery pH or lactate levels obtained at birth. Gestational tissues and maternal bloods were sampled and mRNAs quantified by microarray and RT-PCR. Hypoxia-induced mRNAs in maternal blood rose across labor, an event that induces acute fetal hypoxia. They exhibited a precipitous increase across the second stage of labor, a particularly hypoxic event. Importantly, a hypoxia gene score (sum of the relative expression of four hypoxia-induced genes) strongly correlated with fetal acidemia at birth. Hypoxia-induced mRNAs were also increased in the blood of women carrying severely growth restricted preterm fetuses, a condition of chronic fetal hypoxia. The hypoxia gene score correlated with the severity of ultrasound Doppler velocimetry abnormalities in fetal vessels. Importantly, the hypoxia gene score (derived from mRNA abundance in maternal blood) was significantly correlated with the

  14. Galectin-3 inhibition ameliorates hypoxia-induced pulmonary artery hypertension.

    Science.gov (United States)

    Hao, Mingwen; Li, Miaomiao; Li, Wenjun

    2017-01-01

    Galectin-3 (Gal-3) is a β-galactoside-binding lectin, which is important in inflammation, fibrosis and heart failure. The present study aimed to investigate the role and mechanism of Gal-3 in hypoxia-induced pulmonary arterial hypertension (PAH). Male C57BL/6J and Gal‑3‑/‑ mice were exposed to hypoxia, then the right ventricular systolic pressure (RVSP) and Fulton's index were measured, and Gal‑3 mRNA and protein expression in the pulmonary arteries was analyzed by reverse transcription‑quantitative polymerase chain reaction and western blotting. Compared with the control, hypoxia increased the mRNA and protein expression levels of Gal‑3 in wild type murine pulmonary arteries. Gal‑3 deletion reduced the hypoxia‑induced upregulation of RVSP and Fulton's index. Furthermore, human pulmonary arterial endothelial cells (HPAECs) and human pulmonary arterial smooth muscle cells (HPASMCs) were stimulated by hypoxia in vitro, and Gal‑3 expression was inhibited by small interfering RNA. The inflammatory response of HPAECs, and the proliferation and cell cycle distribution of HPASMCs was also analyzed. Gal‑3 inhibition alleviated the hypoxia‑induced inflammatory response in HPAECs, including tumor necrosis factor‑α and interleukin‑1 secretion, expression of intercellular adhesion molecule‑1 and adhesion of THP‑1 monocytes. Gal‑3 inhibition also reduced hypoxia‑induced proliferation of HPASMCs, partially by reducing cyclin D1 expression and increasing p27 expression. Furthermore, Gal‑3 inhibition suppressed HPASMC switching from a 'contractile' to a 'synthetic' phenotype. In conclusion, Gal‑3 serves a fundamental role in hypoxia‑induced PAH, and inhibition of Gal‑3 may represent a novel therapeutic target for the treatment of hypoxia-induced PAH.

  15. Hypoxia induces oncogene yes-associated protein 1 nuclear translocation to promote pancreatic ductal adenocarcinoma invasion via epithelial-mesenchymal transition.

    Science.gov (United States)

    Wei, Honglong; Xu, Zongzhen; Liu, Feng; Wang, Fuhai; Wang, Xin; Sun, Xueying; Li, Jie

    2017-05-01

    Pancreatic ductal adenocarcinoma is one of the most lethal cancers. The Hippo pathway is involved in tumorigenesis and remodeling of tumor microenvironments. Hypoxia exists in the microenvironment of solid tumors, including pancreatic ductal adenocarcinoma and plays a vital role in tumor progression and metastasis. However, it remains unclear how hypoxia interacts with the Hippo pathway to regulate these events. In this study, expressions of yes-associated protein 1 and hypoxia-inducible factor-1α were found to be elevated in pancreatic ductal adenocarcinoma samples compared with those in matched adjacent non-tumor samples. Moreover, hypoxia-inducible factor-1α expression was positively correlated with yes-associated protein 1 level in pancreatic ductal adenocarcinoma tissues. The higher expression of nuclear yes-associated protein 1 was associated with poor histological grade and prognosis for pancreatic ductal adenocarcinoma patients. In vitro, yes-associated protein 1 was highly expressed in pancreatic ductal adenocarcinoma cells. Depletion of yes-associated protein 1 inhibited the invasion of pancreatic ductal adenocarcinoma cells via downregulation of Vimentin, matrix metalloproteinase-2, and matrix metalloproteinase-13, and upregulation of E-cadherin. In addition, hypoxia promoted the invasion of pancreatic ductal adenocarcinoma cells via regulating the targeted genes. Hypoxia also deactivated the Hippo pathway and induced yes-associated protein 1 nuclear translocation. Furthermore, depletion of yes-associated protein 1 or hypoxia-inducible factor-1α suppressed the invasion of pancreatic ductal adenocarcinoma cells under hypoxia. Mechanism studies showed that nuclear yes-associated protein 1 interacted with hypoxia-inducible factor-1α and activated Snail transcription to participate in epithelial-mesenchymal transition-mediated and matrix metalloproteinase-mediated remodeling of tumor microenvironments. Collectively, yes-associated protein 1 is an

  16. Salidroside exerts protective effects against chronic hypoxia-induced pulmonary arterial hypertension via AMPKα1-dependent pathways.

    Science.gov (United States)

    Chen, Mayun; Cai, Hui; Yu, Chang; Wu, Peiliang; Fu, Yangyang; Xu, Xiaomei; Fan, Rong; Xu, Cunlai; Chen, Yanfan; Wang, Liangxing; Huang, Xiaoying

    2016-01-01

    Salidroside, an active ingredient isolated from Rhodiola rosea, has shown to exert protective effects against chronic hypoxia-induced pulmonary arterial hypertension (PAH). However, the underlying mechanisms were not well known. Based on our recent reports, we predicted the involvement of adenosine monophosphate-activated protein kinase (AMPK) mediated effects in salidroside regulation of PAH. Firstly, to prove the hypothesis, rats were exposed to chronic hypoxia and treated with increasing concentrations of salidroside or a selective AMPK activator-5'-aminoimidazole-4-carboxamide ribonucleoside (AICAR) for 4 weeks. After salidroside or AICAR treatment, the chronic hypoxia-induced right ventricular hypertrophy and pulmonary artery remodeling were attenuated. Then the effects of salidroside or AICAR on hypoxia-induced excess cellular proliferation and apoptosis resistance of pulmonary arterial smooth muscle cells (PASMCs), which contributed to pulmonary arterial remodeling, were investigated. Our results suggested salidroside, as well as AICAR, reversed hypoxia-induced PASMCs proliferation and apoptosis resistance while AMPK inhibitor Compound C enhanced the effects of hypoxia. To reveal the potential cellular mechanisms, activation of AMPKα1 and expression of the genes related to proliferation and apoptosis were analyzed in PASMCs after salidroside treatment under hypoxia conditions. The results demonstrated salidroside as well as AICAR might inhibit chronic hypoxia-induced PASMCs proliferation via AMPKα1-P53-P27/P21 pathway and reverse apoptosis resistance via AMPKα1-P53-Bax/Bcl-2-caspase 9-caspase 3 pathway.

  17. Vitamin C Supplementation Does not Improve Hypoxia-Induced Erythropoiesis

    OpenAIRE

    Martinez-Bello, Vladimir E.; Sanchis-Gomar, Fabian; Martinez-Bello, Daniel; Olaso-Gonzalez, Gloria; Gomez-Cabrera, Mari Carmen; Viña, Jose

    2012-01-01

    Martinez-Bello,Vladimir E., Fabian Sanchis-Gomar, Daniel Martinez-Bello, Gloria Olaso-Gonzalez, Mari Carmen Gomez-Cabrera, and Jose Viña. Vitamin C Supplementation Does Not Improve Hypoxia-Induced Erythropoiesis. High Alt Med Biol 13:269–274, 2012.—Hypoxia induces reactive oxygen species production. Supplements with antioxidant mixtures can compensate for the decline in red cell membrane stability following intermittent hypobaric hypoxia by decreasing protein and lipid oxidation. We aimed to ...

  18. Transcriptional control of adenosine signaling by hypoxia-inducible transcription factors during ischemic or inflammatory disease.

    Science.gov (United States)

    Poth, Jens M; Brodsky, Kelley; Ehrentraut, Heidi; Grenz, Almut; Eltzschig, Holger K

    2013-02-01

    Inflammatory lesions, ischemic tissues, or solid tumors are characterized by the occurrence of severe tissue hypoxia within the diseased tissue. Subsequent stabilization of hypoxia-inducible transcription factors-particularly of hypoxia-inducible factor 1α (HIF1A)--results in significant alterations of gene expression of resident cells or inflammatory cells that have been recruited into such lesions. Interestingly, studies of hypoxia-induced changes of gene expression identified a transcriptional program that promotes extracellular adenosine signaling. Adenosine is a signaling molecule that functions through the activation of four distinct adenosine receptors--the ADORA1, ADORA2A, ADORA2B, and ADORA3 receptors. Extracellular adenosine is predominantly derived from the phosphohydrolysis of precursor nucleotides, such as adenosine triphosphate or adenosine monophosphate. HIF1A-elicited alterations in gene expression enhance the enzymatic capacity within inflamed tissues to produce extracellular adenosine. Moreover, hypoxia-elicited induction of adenosine receptors--particularly of ADORA2B--results in increased signal transduction. Functional studies in genetic models for HIF1A or adenosine receptors implicate this pathway in an endogenous feedback loop that dampens excessive inflammation and promotes injury resolution, while at the same time enhancing ischemia tolerance. Therefore, pharmacological strategies to enhance HIF-elicited adenosine production or to promote adenosine signaling through adenosine receptors are being investigated for the treatment of acute inflammatory or ischemic diseases characterized by tissue hypoxia.

  19. Structural integration in hypoxia-inducible factors

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Dalei; Potluri, Nalini; Lu, Jingping; Kim, Youngchang; Rastinejad, Fraydoon

    2015-08-20

    The hypoxia-inducible factors (HIFs) coordinate cellular adaptations to low oxygen stress by regulating transcriptional programs in erythropoiesis, angiogenesis and metabolism. These programs promote the growth and progression of many tumours, making HIFs attractive anticancer targets. Transcriptionally active HIFs consist of HIF-alpha and ARNT (also called HIF-1 beta) subunits. Here we describe crystal structures for each of mouse HIF-2 alpha-ARNT and HIF-1 alpha-ARNT heterodimers in states that include bound small molecules and their hypoxia response element. A highly integrated quaternary architecture is shared by HIF-2 alpha-ARNT and HIF-1 alpha-ARNT, wherein ARNT spirals around the outside of each HIF-alpha subunit. Five distinct pockets are observed that permit small-molecule binding, including PAS domain encapsulated sites and an interfacial cavity formed through subunit heterodimerization. The DNA-reading head rotates, extends and cooperates with a distal PAS domain to bind hypoxia response elements. HIF-alpha mutations linked to human cancers map to sensitive sites that establish DNA binding and the stability of PAS domains and pockets.

  20. Hypoxia, Hypoxia-inducible Transcription Factors, and Renal Cancer.

    Science.gov (United States)

    Schödel, Johannes; Grampp, Steffen; Maher, Eamonn R; Moch, Holger; Ratcliffe, Peter J; Russo, Paul; Mole, David R

    2016-04-01

    Renal cancer is a common urologic malignancy, and therapeutic options for metastatic disease are limited. Most clear cell renal cell carcinomas (ccRCC) are associated with loss of von Hippel-Lindau tumor suppressor (pVHL) function and deregulation of hypoxia pathways. This review summarizes recent evidence from genetic and biological studies showing that hypoxia and hypoxia-related pathways play critical roles in the development and progress of renal cancer. We used a systematic search for articles using the keywords hypoxia, HIF, renal cancer, and VHL. Identification of the tumor suppressor pVHL has allowed the characterization of important ccRCC-associated pathways. pVHL targets α-subunits of hypoxia-inducible transcription factors (HIF) for proteasomal degradation. The two main HIF-α isoforms have opposing effects on RCC biology, possibly through distinct interactions with additional oncogenes. Furthermore, HIF-1α activity is commonly diminished by chromosomal deletion in ccRCCs, and increased HIF-1 activity reduces tumor burden in xenograft tumor models. Conversely, polymorphisms at the HIF-2α gene locus predispose to the development of ccRCCs, and HIF-2α promotes tumor growth. Genetic studies have revealed a prominent role for chromatin-modifying enzyme genes in ccRCC, and these may further modulate specific aspects of the HIF response. This suggests that, rather than global activation of HIF, specific components of the response are important in promoting kidney cancer. Some of these processes are already targets for current therapeutic strategies, and further dissection of this pathway might yield novel methods of treating RCC. In contrast to many tumor types, HIF-1α and HIF-2α have opposing effects in ccRCC biology, with HIF-1α acting as a tumor suppressor and HIF-2α acting as an oncogene. The overall effect of VHL inactivation will depend on fine-tuning of the HIF response. High levels of hypoxia-inducible transcription factors (HIF) are

  1. Structural and functional analysis of coral Hypoxia Inducible Factor.

    Directory of Open Access Journals (Sweden)

    Didier Zoccola

    Full Text Available Tissues of symbiotic Cnidarians are exposed to wide, rapid and daily variations of oxygen concentration. Indeed, during daytime, intracellular O2 concentration increases due to symbiont photosynthesis, while during night, respiration of both host cells and symbionts leads to intra-tissue hypoxia. The Hypoxia Inducible Factor 1 (HIF-1 is a heterodimeric transcription factor used for maintenance of oxygen homeostasis and adaptation to hypoxia. Here, we carried out a mechanistic study of the response to variations of O2 concentrations of the coral model Stylophora pistillata. In silico analysis showed that homologs of HIF-1 α (SpiHIF-1α and HIF-1β (SpiHIF-1β exist in coral. A specific SpiHIF-1 DNA binding on mammalian Hypoxia Response Element (HRE sequences was shown in extracts from coral exposed to dark conditions. Then, we cloned the coral HIF-1α and β genes and determined their expression and transcriptional activity. Although HIF-1α has an incomplete Oxygen-dependent Degradation Domain (ODD relative to its human homolog, its protein level is increased under hypoxia when tested in mammalian cells. Moreover, co-transfection of SpiHIF-1α and β in mammalian cells stimulated an artificial promoter containing HRE only in hypoxic conditions. This study shows the strong conservation of molecular mechanisms involved in adaptation to O2 concentration between Cnidarians and Mammals whose ancestors diverged about 1,200-1,500 million years ago.

  2. Epithelial Barrier Regulation by Hypoxia-Inducible Factor.

    Science.gov (United States)

    Glover, Louise E; Colgan, Sean P

    2017-09-01

    Mucosal tissues represent surfaces that are exposed to the outside world and provide a conduit for internal and external communication. Tissues such as the intestine and the lung are lined by layer(s) of epithelial cells that, when organized in three dimensions, provide a critical barrier to the flux of luminal contents. This selective barrier is provided through the regulated expression of junctional proteins and mucins. Tissue oxygen metabolism is central to the maintenance of homeostasis in the mucosa. In some organs (e.g., the colon), low baseline Po2 determines tissue metabolism and results in basal expression of the transcription factor, hypoxia-inducible factor (HIF), which is enhanced after ischemia/inflammation. Recent studies have indicated that HIF contributes fundamentally to the expression of barrier-related genes and in the regulation of barrier-adaptive responses within the mucosa. Here, we briefly review recent literature on the topic of hypoxia and HIF regulation of barrier in mucosal health and during disease.

  3. Hypoxia-inducible transcription factor-1α promotes hypoxia-induced A549 apoptosis via a mechanism that involves the glycolysis pathway

    Directory of Open Access Journals (Sweden)

    Cao GuiQun

    2006-01-01

    Full Text Available Abstract Background Hypoxia-inducible transcription factor-1α (HIF-1α, which plays an important role in controlling the hypoxia-induced glycolysis pathway, is a "master" gene in the tissue hypoxia response during tumor development. However, its role in the apoptosis of non-small cell lung cancer remains unknown. Here, we have studied the effects of HIF-1α on apoptosis by modulating HIF-1α gene expression in A549 cells through both siRNA knock-down and over-expression. Methods A549 cells were transfected with a HIF-1α siRNA plasmid or a HIF-1α expression vector. Transfected cells were exposed to a normoxic or hypoxic environment in the presence or absence of 25 mM HEPES and 2-deoxyglucose (2-DG (5 mM. The expression of three key genes of the glycolysis pathway, glucose transporter type 1(GLUT1, phosphoglycerate kinase 1(PGK1, and hexokinase 1(HK1, were measured using real-time RT-PCR. Glycolysis was monitored by measuring changes of pH and lactate concentration in the culture medium. Apoptosis was detected by TUNEL assay and flow cytometry. Results Knocking down expression of HIF-1α inhibited the glycolysis pathway, increased the pH of the culture medium, and protected the cells from hypoxia-induced apoptosis. In contrast, over-expression of HIF-1α accelerated glycolysis in A549 cells, decreased the pH of the culture medium, and enhanced hypoxia-induced apoptosis. These effects of HIF-1α on glycolysis, pH of the medium, and apoptosis were reversed by treatment with the glycolytic inhibitor, 2-DG. Apoptosis induced by HIF-1α over-expression was partially inhibited by increasing the buffering capacity of the culture medium by adding HEPES. Conclusion During hypoxia in A549 cells, HIF-1α promotes activity of the glycolysis pathway and decreases the pH of the culture medium, resulting in increased cellular apoptosis.

  4. Ascorbic acid does not enhance hypoxia-induced vasodilation in healthy older men.

    Science.gov (United States)

    Pollock, Jonathan P; Patel, Hardikkumar M; Randolph, Brittney J; Heffernan, Matthew J; Leuenberger, Urs A; Muller, Matthew D

    2014-07-01

    In response to hypoxia, a net vasodilation occurs in the limb vasculature in young healthy humans and this is referred to as "hypoxia-induced vasodilation". We performed two separate experiments to determine (1) if hypoxia-induced forearm vasodilation is impaired in older men (n = 8) compared to young men (n = 7) and (2) if acute systemic infusion of ascorbic acid would enhance hypoxia-induced vasodilation in older men (n = 8). Heart rate, mean arterial pressure, oxygen saturation, minute ventilation, forearm vascular conductance (FVC, Doppler ultrasound), and cutaneous vascular conductance (CVC, laser Doppler flowmetry) were recorded continuously while subjects breathed 10% oxygen for 5 min. Changes from baseline were compared between groups and between treatments. The older adults had a significantly attenuated increase in FBF (13 ± 4 vs. 30 ± 7%) and FVC (16 ± 4 vs. 30 ± 7%) in response to 5 min of hypoxia. However, skin blood flow responses were comparable between groups (young: 35 ± 9, older: 30 ± 6%). In Experiment 2, FVC responses to 5 min of breathing 10% oxygen were not significantly different following saline (3 ± 10%) and ascorbic acid (8 ± 10%) in the older men. Ascorbic acid also had no physiological effects in the young men. These findings advance our basic understanding of how aging influences vascular responses to hypoxia and suggest that, in healthy humans, hypoxia-induced vasodilation is not restrained by reactive oxygen species. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  5. Expression of hypoxia inducible factor 1 alpha and its clinical significance in esophageal carcinoma: A meta-analysis.

    Science.gov (United States)

    Jing, Shao Wu; Wang, Jun; Xu, Qing

    2017-07-01

    Many studies have analyzed the relationship between hypoxia inducible factor 1 alpha expression and its relation to differentiation, lymph node metastasis, and other clinicopathological variables of esophageal carcinoma, but the results are still inconsistent. This meta-analysis was carried out to explore hypoxia inducible factor 1 alpha in esophageal carcinoma and its correlation with clinicopathological features and prognosis, in order to provide comprehensive reference for clinic. A total of 18 studies including 1566 patients with esophageal squamous cell carcinoma were enrolled. The results showed that compared with para-carcinoma tissue, the expression of hypoxia inducible factor 1 alpha was significantly enhanced (odds ratio = 0.122, 95% confidence interval = 0.074-0.201, p = 0.000); hypoxia inducible factor 1 alpha was associated with differentiation (odds ratio = 1.458, 95% confidence interval = 1.108-1.920, p = 0.007), T classification (odds ratio = 0.457, 95% confidence interval = 0.265-0.786, p = 0.005), lymph node metastasis (odds ratio = 0.337, 95% confidence interval = 0.185-0.614, p = 0.000), and pathological tumor-node-metastasis stage (odds ratio = 0.362, 95% confidence interval = 0.177-0.740, p = 0.005), whereas there was no relation to histological grade, lymphatic vessel invasion, blood vessel invasion, 3- to 5-year overall survival and disease-free survival. Patients with hypoxia inducible factor 1 alpha overexpression had poor differentiation, increased depth of tumor invasion, more lymph node metastasis, and late pathological tumor-node-metastasis stage. Hypoxia inducible factor 1 alpha could be an indicator for differentiation, T classification, lymph node metastasis, and pathological tumor-node-metastasis stage, and it is worth further study.

  6. Hypoxia-induced retinopathy model in adult zebrafish

    DEFF Research Database (Denmark)

    Cao, Ziquan; Jensen, Lasse D.; Rouhi, Pegah

    2010-01-01

    Hypoxia-induced vascular responses, including angiogenesis, vascular remodeling and vascular leakage, significantly contribute to the onset, development and progression of retinopathy. However, until recently there were no appropriate animal disease models recapitulating adult retinopathy available....... In this article, we describe protocols that create hypoxia-induced retinopathy in adult zebrafish. Adult fli1: EGFP zebrafish are placed in hypoxic water for 3-10 d and retinal neovascularization is analyzed using confocal microscopy. It usually takes 11 d to obtain conclusive results using the hypoxia......-induced retinopathy model in adult zebrafish. This model provides a unique opportunity to study kinetically the development of retinopathy in adult animals using noninvasive protocols and to assess therapeutic efficacy of orally active antiangiogenic drugs....

  7. Global hypoxia induced impairment in learning and spatial memory is associated with precocious hippocampal aging.

    Science.gov (United States)

    Biswal, Suryanarayan; Sharma, Deepti; Kumar, Kushal; Nag, Tapas Chandra; Barhwal, Kalpana; Hota, Sunil Kumar; Kumar, Bhuvnesh

    2016-09-01

    Both chronological aging and chronic hypoxia stress have been reported to cause degeneration of hippocampal CA3 neurons and spatial memory impairment through independent pathways. However, the possible occurrence of precocious biological aging on exposure to single episode of global hypoxia resulting in impairment of learning and memory remains to be established. The present study thus aimed at bridging this gap in existing literature on hypoxia induced biological aging. Male Sprague Dawley rats were exposed to simulated hypobaric hypoxia (25,000ft) for different durations and were compared with aged rats. Behavioral studies in Morris Water Maze showed decline in learning abilities of both chronologically aged as well as hypoxic rats as evident from increased latency and pathlength to reach target platform. These behavioral changes in rats exposed to global hypoxia were associated with deposition of lipofuscin and ultrastructural changes in the mitochondria of hippocampal neurons that serve as hallmarks of aging. A single episode of chronic hypobaric hypoxia exposure also resulted in the up-regulation of pro-aging protein, S100A9 and down regulation of Tau, SNAP25, APOE and Sod2 in the hippocampus similar to that in aged rats indicating hypoxia induced accelerated aging. The present study therefore provides evidence for role of biological aging of hippocampal neurons in hypoxia induced impairment of learning and memory. Copyright © 2016. Published by Elsevier Inc.

  8. The Protective Effect of Salidroside on Hypoxia-Induced Corpus Cavernosum Smooth Muscle Cell Phenotypic Transformation.

    Science.gov (United States)

    Zhang, Xiang; Zhao, Jian-Feng; Zhao, Fan; Yan, Jun-Feng; Yang, Fan; Huang, Xiao-Jun; Chen, Gang; Fu, Hui-Ying; Lv, Bo-Dong

    2017-01-01

    Salidroside, a major active ingredient isolated from Rhodiola rosea, has a long application in Chinese medical history. It has widely demonstrated effects on fatigue, psychological stress, and depression and exhibits potential antihypoxia activity. Emerging evidence shows that hypoxia is an important independent risk factor for erectile dysfunction (ED). The aim of this study was to clarify the effect of salidroside on hypoxia-induced phenotypic transformation of corpus cavernosum smooth muscle cells (CCSMCs). Our results showed that salidroside decreased the hypoxia-induced expression of collagen and content of vimentin, a corpus cavernosum smooth muscle synthetic protein, in vitro. Simultaneously, salidroside increased expression of the CCSMC contractile proteins, α-smooth muscle actin (α-SMA) and desmin. In vivo, similarly, the expressions of collagen and hypoxia-inducible factor-1α were increased in bilateral cavernous neurectomy (BCN) rats while they were decreased in the salidroside group. Among the phenotypic proteins, α-SMA and desmin increased and vimentin decreased after treating BCN rats with salidroside compared with the BCN alone group. Overall, our results demonstrate that salidroside has the ability to oppose hypoxia and can inhibit the CCSMC phenotypic transformation induced by hypoxia. Salidroside may provide a new treatment method for ED.

  9. The Protective Effect of Salidroside on Hypoxia-Induced Corpus Cavernosum Smooth Muscle Cell Phenotypic Transformation

    Directory of Open Access Journals (Sweden)

    Xiang Zhang

    2017-01-01

    Full Text Available Salidroside, a major active ingredient isolated from Rhodiola rosea, has a long application in Chinese medical history. It has widely demonstrated effects on fatigue, psychological stress, and depression and exhibits potential antihypoxia activity. Emerging evidence shows that hypoxia is an important independent risk factor for erectile dysfunction (ED. The aim of this study was to clarify the effect of salidroside on hypoxia-induced phenotypic transformation of corpus cavernosum smooth muscle cells (CCSMCs. Our results showed that salidroside decreased the hypoxia-induced expression of collagen and content of vimentin, a corpus cavernosum smooth muscle synthetic protein, in vitro. Simultaneously, salidroside increased expression of the CCSMC contractile proteins, α-smooth muscle actin (α-SMA and desmin. In vivo, similarly, the expressions of collagen and hypoxia-inducible factor-1α were increased in bilateral cavernous neurectomy (BCN rats while they were decreased in the salidroside group. Among the phenotypic proteins, α-SMA and desmin increased and vimentin decreased after treating BCN rats with salidroside compared with the BCN alone group. Overall, our results demonstrate that salidroside has the ability to oppose hypoxia and can inhibit the CCSMC phenotypic transformation induced by hypoxia. Salidroside may provide a new treatment method for ED.

  10. Inactivation of lysyl oxidase by β-aminopropionitrile inhibits hypoxia-induced invasion and migration of cervical cancer cells.

    Science.gov (United States)

    Yang, Xiaoxiao; Li, Shifeng; Li, Wande; Chen, Jingkao; Xiao, Xiao; Wang, Youqiong; Yan, Guangmei; Chen, Lijun

    2013-02-01

    Tumor invasion and migration are major causes of mortality in patients with cervical carcinoma. Tumors under hypoxic conditions are more invasive and have a higher metastasic activity. Lysyl oxidase (LOX) is a hypoxia-responsive gene. LOX has been shown to be essential for hypoxia-induced metastasis in breast cancer. However, the direct impact of LOX on cervical cancer cell motility remains poorly understood. Our study revealed that LOX expression at protein and catalytic levels is upregulated in cervical cancer cells upon exposure to hypoxia. Hypoxia induced mesenchymal-like morphological changes in HeLa and SiHa cells which were accompanied by upregulation of α-SMA and vimentin, two mesenchymal markers, and downregulation of E-cadherin, an epithelial marker, indicating the epithelial-mesenchymal transition (EMT) of cervical cancer cells occurred under hypoxic conditions. Treatment of tumor cells with β-aminopropionitrile (BAPN), an active site inhibitor of LOX, blocked the hypoxia-induced EMT morphological and marker protein changes, and inhibited invasion and migration capacities of cervical carcinoma cells in vitro. Collectively, these findings suggest LOX enhances hypoxia-induced invasion and migration in cervical cancer cells mediated by the EMT which can be inhibited by BAPN.

  11. Hypoxia-inducible factor 1-α in chronic gastrointestinal ischemia

    NARCIS (Netherlands)

    Harki, Jihan; Sana, Aria; van Noord, Désirée; van Diest, Paul J; van der Groep, Petra; Kuipers, Ernst J; Moons, Leon M G; Biermann, Katharina; Tjwa, Eric T T L

    Chronic gastrointestinal ischemia (CGI) is the result of decreased mucosal perfusion. Typical histological characteristics are lacking which hamper its early diagnosis. Hypoxia-inducible factor-1α (HIF-1α) is expressed under acute hypoxia. We investigated HIF-1α expression in chronic ischemic and

  12. Hypoxia-inducible factor 1-α in chronic gastrointestinal ischemia

    NARCIS (Netherlands)

    J. Harki (Jihan); A. Sana (Aria); D. van Noord (Désirée); P.J. van Diest (Paul); P. van der Groep (Petra); E.J. Kuipers (Ernst); L.M.G. Moons (Leon); K. Biermann (Katharina); E.T.T.L. Tjwa (Eric)

    2014-01-01

    textabstractChronic gastrointestinal ischemia (CGI) is the result of decreased mucosal perfusion. Typical histological characteristics are lacking which hamper its early diagnosis. Hypoxia-inducible factor-1α (HIF-1α) is expressed under acute hypoxia. We investigated HIF-1α expression in chronic

  13. Hypoxia-inducible factor 1-alpha in chronic gastrointestinal ischemia

    NARCIS (Netherlands)

    Harki, J.; Sana, A.; Noord, D. van; Diest, P.J. van; Groep, P. van der; Kuipers, E.J.; Moons, L.M.; Biermann, K.; Tjwa, E.T.

    2015-01-01

    Chronic gastrointestinal ischemia (CGI) is the result of decreased mucosal perfusion. Typical histological characteristics are lacking which hamper its early diagnosis. Hypoxia-inducible factor-1alpha (HIF-1alpha) is expressed under acute hypoxia. We investigated HIF-1alpha expression in chronic

  14. Role of hypoxia-inducible factor in diabetic myocardial hypertrophy

    African Journals Online (AJOL)

    elevation of hypoxia inducible factor (HIF), which in turn leads to increases in levels of VEGF and other angiogenic factors. This adaptive response delays progression from pathological cardiac hypertrophy to heart failure. In early cardiac hypertrophy, stability of HIF-1 promotes glycolysis, which improves glucose utilization ...

  15. Hypoxia-inducible factor as an angiogenic master switch

    Directory of Open Access Journals (Sweden)

    Takuya eHashimoto

    2015-04-01

    Full Text Available Hypoxia-inducible factors (HIFs regulate the transcription of genes that mediate the response to hypoxia. HIFs are constantly expressed and degraded under normoxia, but stabilized under hypoxia. HIFs have been widely studied in physiological and pathological conditions and have been shown to contribute to the pathogenesis of various vascular diseases. In clinical settings, the HIF pathway has been studied for its role in inhibiting carcinogenesis. HIFs might also play a protective role in the pathology of ischemic diseases. Clinical trials of therapeutic angiogenesis after the administration of a single growth factor have yielded unsatisfactory or controversial results, possibly because the coordinated activity of different HIF-induced factors is necessary to induce mature vessel formation. Thus, manipulation of HIF activity to simultaneously induce a spectrum of angiogenic factors offers a superior strategy for therapeutic angiogenesis. Because HIF-2α plays an essential role in vascular remodeling, manipulation of HIF-2α is a promising approach to the treatment of ischemic diseases caused by arterial obstruction, where insufficient development of collateral vessels impedes effective therapy. eIF3e/INT6 interacts specifically with HIF-2α and induces the proteasome inhibitor-sensitive degradation of HIF-2α, independent of hypoxia and VHL. Treatment with eIF3e/INT6 siRNA stabilizes HIF-2α activity even under normoxic conditions and induces the expression of several angiogenic factors, at levels sufficient to produce functional arteries and veins in vivo. We have demonstrated that administration of eIF3e/INT6 siRNA to ischemic limbs or cold-injured brains reduces ischemic damage in animal models. This review summarizes the current understanding of the relationship between HIFs and vascular diseases. We also discuss novel oxygen-independent regulatory proteins that bind HIF-α and the implications of a new method for therapeutic angiogenesis

  16. Differential sensitivity of oxidative and glycolytic muscles to hypoxia-induced muscle atrophy.

    Science.gov (United States)

    de Theije, C C; Langen, R C J; Lamers, W H; Gosker, H R; Schols, A M W J; Köhler, S E

    2015-01-15

    Hypoxia as a consequence of acute and chronic respiratory disease has been associated with muscle atrophy. This study investigated the sensitivity of oxidative and glycolytic muscles to hypoxia-induced muscle atrophy. Male mice were exposed to 8% normobaric oxygen for up to 21 days. Oxidative soleus and glycolytic extensor digitorum longus (EDL) muscles were isolated, weighed, and assayed for expression profiles of the ubiquitin-proteasome system (UPS), the autophagy-lysosome pathway (ALP), and glucocorticoid receptor (GR) and hypoxia-inducible factor-1α (HIF1α) signaling. Fiber-type composition and the capillary network were investigated. Hypoxia-induced muscle atrophy was more prominent in the EDL than the soleus muscle. Although increased expression of HIF1α target genes showed that both muscle types sensed hypoxia, their adaptive responses differed. Atrophy consistently involved a hypoxia-specific effect (i.e., not attributable to a hypoxia-mediated reduction of food intake) in the EDL only. Hypoxia-specific activation of the UPS and ALP and increased expression of the glucocorticoid receptor (Gr) and its target genes were also mainly observed in the EDL. In the soleus, stimulation of gene expression of those pathways could be mimicked to a large extent by food restriction alone. Hypoxia increased the number of capillary contacts per fiber cross-sectional area in both muscles. In the EDL, this was due to type II fiber atrophy, whereas in the soleus the absolute number of capillary contacts increased. These responses represent two distinct modes to improve oxygen supply to muscle fibers, but may aggravate muscle atrophy in chronic obstructive pulmonary disease patients who have a predominance of type II fibers. Copyright © 2015 the American Physiological Society.

  17. L-arginine Attenuates Hypobaric Hypoxia-Induced Increase in Ornithine Decarboxylase 1.

    Science.gov (United States)

    Yuhong, Li; Zhengzhong, Bai; Feng, Tang; Quanyu, Yang; Ge, Ri-Li

    2017-12-01

    Chronic hypoxia-induced pulmonary hypertension and vascular remodeling have been shown to be associated with ornithine decarboxylase 1 (ODC1). However, few animal studies have investigated the role of ODC1 in acute hypoxia. We investigated ODC1 gene expression, morphologic and functional changes, and the effect of L-arginine as an attenuator in lung tissues of rats exposed to acute hypobaric hypoxia at a simulated altitude of 6000 m. Sprague-Dawley rats exposed to simulated hypobaric hypoxia (6000 m) for 24, 48, or 72 hours were treated with L-arginine (L-arginine group, 20 mg/100 g intraperitoneal; n=15) or untreated (non-L-arginine group, n=15). Control rats (n=5) were maintained at 2260 m in a normal environment for the same amount of time but were treated without L-arginine. The mean pulmonary artery pressure was measured by PowerLab system. The morphologic and immunohistochemical changes in lung tissue were observed under a microscope. The mRNA and protein levels of ODC1 were measured by real-time polymerase chain reaction and Western-blot, respectively. Hypobaric hypoxia induced pulmonary interstitial hyperemia and capillary expansion in the lungs of rats exposed to acute hypoxia at 6000 m. The mean pulmonary artery pressure and the mRNA and protein levels of ODC1 were significantly increased, which could be attenuated by treatment with L-arginine. L-arginine attenuates acute hypobaric hypoxia-induced increase in mean pulmonary artery pressure and ODC1 gene expression in lung tissues of rats. ODC1 gene contributes to the development of hypoxic pulmonary hypertension. Copyright © 2017. Published by Elsevier Inc.

  18. A viral vector expressing hypoxia-inducible factor 1 alpha inhibits hippocampal neuronal apoptosis

    OpenAIRE

    Chai, Xiqing; Kong, Weina; Liu, Lingyun; Yu, Wenguo; Zhang, Zhenqing; Sun, Yimin

    2014-01-01

    Hypoxia-inducible factor 1 (HIF-1) attenuates amyloid-beta protein neurotoxicity and decreases apoptosis induced by oxidative stress or hypoxia in cortical neurons. In this study, we constructed a recombinant adeno-associated virus (rAAV) vector expressing the human HIF-1α gene (rAAV-HIF-1α), and tested the assumption that rAAV-HIF-1α represses hippocampal neuronal apoptosis induced by amyloid-beta protein. Our results confirmed that rAAV-HIF-1α significantly reduces apoptosis induced by amyl...

  19. [Effect of hypoxia-inducible factor-1α, endothelin-1 and inducible nitric oxide synthase in the pathogenesis of hypoxia-induced pulmonary hypertension of the neonatal rats].

    Science.gov (United States)

    Sang, Kui; Zhou, Ying; Li, Ming-xia

    2012-12-01

    To study the effect of hypoxia-inducible factor-1α (HIF-1α) in the pathogenesis of hypoxia-induced pulmonary hypertension (HPH) of the neonatal rats through the study on the expression level of HIF-1α and its regulation factors: endothelin-1 (ET-1) and inducible nitric oxide synthase (iNOS) in blood serum and lung tissue. To make an HPH model of neonatal rats, 120 newborn Wistar rats were divided at random into two groups: HPH group and the regular oxygen controlled group with the same birthday. The rats of the two groups were put in the condition of hypoxia for 3, 5, 7, 10, 14, 21 days and then 10 rats of HPH group and control group were picked up, their mean pulmonary arterial pressure (mPAP), serum HIF-1α, and iNOS, and ET-1 content were tested, and finally their lung tissue was taken after they were sacrificed and the expression level of the gene mRNA of HIF-1α, iNOS and ET-1. (1) The rats experienced hypoxia for 3, 5, 7, 10, 14 or 21 days had an increasing mPAP: [8.47 ± 1.45, 10.04 ± 1.69, 10.89 ± 2.97, 16.96 ± 1.97, 13.01 ± 1.93, 21.04 ± 2.13 (mm Hg)], which had a significant differences compared with control groups [5.11 ± 1.06, 8.12 ± 1.11, 8.77 ± 0.92, 12.23 ± 1.78, 8.89 ± 0.89, 11.09 ± 1.64 (mm Hg)] (P rats in hypoxia group had a higher serum HIF-1α [0.83 ± 0.07, 0.84 ± 0.17, 0.97 ± 0.13, 1.10 ± 0.30, 0.92 ± 0.19 (pg/nmol)] than the control group [0.26 ± 0.20, 0.37 ± 0.16, 0.44 ± 0.18, 0.41 ± 0.23, 0.66 ± 0.18 (pg/nmol)] as they experienced hypoxia for 3, 5, 7, 10, and 14 days (P 0.05), and the content of serum iNOS after hypoxia for 14 or 21 days (4.56 ± 0.96, 5.86 ± 1.76) µmol/L was lower than that of the control group (10.35 ± 1.99, 8.44 ± 2.76) µmol/L (P rats and causedn a imbalance of ET-1 and NO. HIF-1α, ET-1 and iNOS altogether contributed to the occurrence and development of HPH in neonatal rats.

  20. Glutamatergic neurotransmission modulates hypoxia-induced hyperventilation but not anapyrexia

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    Paula P.M. de

    2004-01-01

    Full Text Available The interaction between pulmonary ventilation (V E and body temperature (Tb is essential for O2 delivery to match metabolic rate under varying states of metabolic demand. Hypoxia causes hyperventilation and anapyrexia (a regulated drop in Tb, but the neurotransmitters responsible for this interaction are not well known. Since L-glutamate is released centrally in response to peripheral chemoreceptor stimulation and glutamatergic receptors are spread in the central nervous system we tested the hypothesis that central L-glutamate mediates the ventilatory and thermal responses to hypoxia. We measured V E and Tb in 40 adult male Wistar rats (270 to 300 g before and after intracerebroventricular injection of kynurenic acid (KYN, an ionotropic glutamatergic receptor antagonist, alpha-methyl-4-carboxyphenylglycine (MCPG, a metabotropic glutamatergic receptor antagonist or vehicle (saline, followed by a 1-h period of hypoxia (7% inspired O2 or normoxia (humidified room air. Under normoxia, KYN (N = 5 or MCPG (N = 8 treatment did not affect V E or Tb compared to saline (N = 6. KYN and MCPG injection caused a decrease in hypoxia-induced hyperventilation (595 ± 49 for KYN, N = 7 and 525 ± 84 ml kg-1 min-1 for MCPG, N = 6; P < 0.05 but did not affect anapyrexia (35.3 ± 0.2 for KYN and 34.7 ± 0.4ºC for MCPG compared to saline (912 ± 110 ml kg-1 min-1 and 34.8 ± 0.2ºC, N = 8. We conclude that glutamatergic receptors are involved in hypoxic hyperventilation but do not affect anapyrexia, indicating that L-glutamate is not a common mediator of this interaction.

  1. Hypoxia Induces Autophagy through Translational Up-Regulation of Lysosomal Proteins in Human Colon Cancer Cells.

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    Ming-Chih Lai

    Full Text Available Hypoxia occurs in a wide variety of physiological and pathological conditions, including tumorigenesis. Tumor cells have to adapt to hypoxia by altering their gene expression and protein synthesis. Here, we showed that hypoxia inhibits translation through activation of PERK and inactivation of mTOR in human colon cancer HCT116 cells. Prolonged hypoxia (1% O2, 16 h dramatically inhibits general translation in HCT116 cells, yet selected mRNAs remain efficiently translated under such a condition. Using microarray analysis of polysome- associated mRNAs, we identified a large number of hypoxia-regulated genes at the translational level. Efficiently translated mRNAs during hypoxia were validated by polysome profiling and quantitative real-time RT-PCR. Pathway enrichment analysis showed that many of the up-regulated genes are involved in lysosome, glycan and lipid metabolism, antigen presentation, cell adhesion, and remodeling of the extracellular matrix and cytoskeleton. The majority of down-regulated genes are involved in apoptosis, ubiquitin-mediated proteolysis, and oxidative phosphorylation. Further investigation showed that hypoxia induces lysosomal autophagy and mitochondrial dysfunction through translational regulation in HCT116 cells. The abundance of several translation factors and the mTOR kinase activity are involved in hypoxia-induced mitochondrial autophagy in HCT116 cells. Our studies highlight the importance of translational regulation for tumor cell adaptation to hypoxia.

  2. Role of Hypoxia-inducible factor-1 and its target genes in human lung adenocarcinoma cells after photon- versus carbon ion irradiation; Expression HIF-1-abhaengiger Gene in humanen Lungenadenokarzinom (A549)-Zellen und deren Regulation nach Photonen- und Schwerionenbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Bill, Verena Maria

    2013-11-26

    Exposed to hypoxia tumor cells are notably resistant to photon irradiation. The hypoxiainducible transcription factor 1α (HIF-1α) seems to play a fundamental role in this resistance, while its role after heavy-ion beam remains unknown. The intention of this study was to determine how A549-cells (non-small-cell lung carcinoma) react in different oxygenation states after irradiation with photons or heavy ions, particularly in regards to their expression of HIF-1 target genes. Resistance of hypoxic A549 cells after photon irradiation was documented by cellular and clonogenic survival. In contrast, cellular survival after heavy-ion irradiation in hypoxic cells was not elevated to normoxic cells. Among the oxygen dependent regulation of HIF-1 target genes, gene expression analyses showed an increased expression of GLUT-1, LDH-A, PDK-1 and VEGF after photon irradiation but not after heavy-ion irradiation after 48 hours in normoxic cells. As expected, CDKN1A as inhibitor of cell cycle progression showed higher expression after both radiation forms; interestingly CDKN1A was also in an oxygen dependent manner lightly upregulated. In western blot analyses we demonstrated a significant increase of HIF-1 and GLUT-1 caused by hypoxia, but only a tendency of increased protein level in hypoxia after photon irradiation and no changes after heavy-ion irradiation. Significantly higher protein level of secreted VEGF-A could be measured 72 hours after photon irradiation in normoxic cells by ELISA analyses. Controversially discussed, I could not detect an association between HIF-1 and SCF or Trx-1 in A549-cells in this study. Whereas Trx-1-expression was neither influenced by changed oxygen partial pressure nor irradiation, I could show increased SCF mRNA by quantitative Real Time-PCR and secreted protein level by ELISA after photon irradiation independent of oxygen state. In summary, this study showed that HIF-1 and its target genes (GLUT-1, LDHA; PDK, VEGF) and also SCF was

  3. Hypoxia-Inducible Factor 3 Is an Oxygen-Dependent Transcription Activator and Regulates a Distinct Transcriptional Response to Hypoxia

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    Peng Zhang

    2014-03-01

    Full Text Available Hypoxia-inducible factors (HIFs play key roles in the cellular response to hypoxia. It is widely accepted that whereas HIF-1 and HIF-2 function as transcriptional activators, HIF-3 inhibits HIF-1/2α action. Contrary to this idea, we show that zebrafish Hif-3α has strong transactivation activity. Hif-3α is degraded under normoxia. Mutation of P393, P493, and L503 inhibits this oxygen-dependent degradation. Transcriptomics and chromatin immunoprecipitation analyses identify genes that are regulated by Hif-3α, Hif-1α, or both. Under hypoxia or when overexpressed, Hif-3α binds to its target gene promoters and upregulates their expression. Dominant-negative inhibition and knockdown of Hif-3α abolish hypoxia-induced Hif-3α-promoter binding and gene expression. Hif-3α not only mediates hypoxia-induced growth and developmental retardation but also possesses hypoxia-independent activities. Importantly, transactivation activity is conserved and human HIF-3α upregulates similar genes in human cells. These findings suggest that Hif-3 is an oxygen-dependent transcription factor and activates a distinct transcriptional response to hypoxia.

  4. Clinical Aspects of Hypoxia-inducible Factors in Colorectal Cancer

    DEFF Research Database (Denmark)

    Havelund, Birgitte Mayland; Spindler, Karen-Lise Garm; Sørensen, Flemming Brandt

    Clinical Aspects of Hypoxia-inducible Factors in Colorectal Cancer   Birgitte Mayland Havelund1,4 MD, Karen-Lise Garm Spindler1,4 MD, PhD, Flemming Brandt Sørensen2,4 MD, DMSc, Ivan Brandslund3 MD, DMSc, Anders Jakobsen1,4 MD, DMSc. 1Department of Oncology, 2Pathology and 3Biochemistry, Vejle...... Hospital, Vejle, Denmark 4Institute of Regional Health Services Research, University of Southern Denmark, Odense Denmark Background Prognostic and predictive markers are needed for individualizing the treatment of colorectal cancer. Hypoxia-inducible factor 1α (HIF-1α) is a transcription-inducing factor...... is to investigate the predictive and prognostic value of HIF-1α in colorectal cancer. Materials and Methods The project is divided into 3 substudies: 1. Biological and methodological aspects. The expression of HIF-1α measured by immunohistochemistry in paraffin embedded tissue is related to single nucleotide...

  5. Mechanism of hypoxia-induced NFκB

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    Melvin, Andrew; Mudie, Sharon

    2011-01-01

    The cellular response to hypoxia relies on the activation of a specific transcriptional program. Although, most of the attention is focused on the transcription factor HIF, other transcription factors are also activated in hypoxia. We have recently described the mechanism for hypoxia induced NFκB. We have demonstrated the crucial dependency on the IKK complex as well as in the upstream IKK kinase TAK1. TAK1 and IKK activation is dependent upon the calcium calmodulin kinase, CaMK2 and requires Ubc13 as the E2 ubiquitin conjugation enzyme. We report a role for XIAP as the possible E3-ubiquitin ligase for this system. Interestingly, hypoxia induced IKK mediated phosphorylation of IκBα, does not lead to degradation. Hypoxia prevents IκBα de-sumoylation of Sumo-2/3 chains on critical lysine residues, normally required for K-48 linked polyubiquitination. Our results define a novel pathway regulating NFκB activation. PMID:21325892

  6. Megakaryocytic leukemia 1 (MKL1 regulates hypoxia induced pulmonary hypertension in rats.

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    Zhibin Yuan

    Full Text Available Hypoxia induced pulmonary hypertension (HPH represents a complex pathology that involves active vascular remodeling, loss of vascular tone, enhanced pulmonary inflammation, and increased deposition of extracellular matrix proteins. Megakaryocytic leukemia 1 (MKL1 is a transcriptional regulator known to influence cellular response to stress signals in the vasculature. We report here that in response to chronic hypobaric hypoxia, MKL1 expression was up-regulated in the lungs in rats. Short hairpin RNA (shRNA mediated depletion of MKL1 significantly ameliorated the elevation of pulmonary arterial pressure in vivo with a marked alleviation of vascular remodeling. MKL1 silencing also restored the expression of NO, a key vasoactive molecule necessary for the maintenance of vascular tone. In addition, hypoxia induced pulmonary inflammation was dampened in the absence of MKL1 as evidenced by normalized levels of pro-inflammatory cytokines and chemokines as well as reduced infiltration of pro-inflammatory immune cells in the lungs. Of note, MKL1 knockdown attenuated fibrogenesis in the lungs as indicated by picrosirius red staining. Finally, we demonstrate that MKL1 mediated transcriptional activation of type I collagen genes in smooth muscle cells under hypoxic conditions. In conclusion, we data highlight a previously unidentified role for MKL1 in the pathogenesis of HPH and as such lay down groundwork for future investigation and drug development.

  7. Hypoxia-inducible Lipid Droplet-associated (HILPDA) Is a Novel Peroxisome Proliferator-activated Receptor (PPAR) Target Involved in Hepatic Triglyceride Secretion

    NARCIS (Netherlands)

    Mattijsen, F.; Georgiadi, A.; Andasarie, T.; Szalowska, E.; Zota, A.; Krones-Herzig, A.; Kersten, A.H.

    2014-01-01

    Peroxisome proliferator-activated receptors (PPARs) play major roles in the regulation of hepatic lipid metabolism through the control of numerous genes involved in processes such as lipid uptake and fatty acid oxidation. Here we identify hypoxia-inducible lipid droplet-associated (Hilpda/Hig2) as a

  8. Hypoxia induces mitochondrial mutagenesis and dysfunction in inflammatory arthritis.

    LENUS (Irish Health Repository)

    Biniecka, Monika

    2012-02-01

    OBJECTIVE: To assess the levels and spectrum of mitochondrial DNA (mtDNA) point mutations in synovial tissue from patients with inflammatory arthritis in relation to in vivo hypoxia and oxidative stress levels. METHODS: Random Mutation Capture assay was used to quantitatively evaluate alterations of the synovial mitochondrial genome. In vivo tissue oxygen levels (tPO(2)) were measured at arthroscopy using a Licox probe. Synovial expression of lipid peroxidation (4-hydroxynonenal [4-HNE]) and mitochondrial cytochrome c oxidase subunit II (CytcO II) deficiency were assessed by immunohistochemistry. In vitro levels of mtDNA point mutations, reactive oxygen species (ROS), mitochondrial membrane potential, and markers of oxidative DNA damage (8-oxo-7,8-dihydro-2\\'-deoxyguanine [8-oxodG]) and lipid peroxidation (4-HNE) were determined in human synoviocytes under normoxia and hypoxia (1%) in the presence or absence of superoxide dismutase (SOD) or N-acetylcysteine (NAC) or a hydroxylase inhibitor (dimethyloxalylglycine [DMOG]). Patients were categorized according to their in vivo tPO(2) level (<20 mm Hg or >20 mm Hg), and mtDNA point mutations, immunochemistry features, and stress markers were compared between groups. RESULTS: The median tPO(2) level in synovial tissue indicated significant hypoxia (25.47 mm Hg). Higher frequency of mtDNA mutations was associated with reduced in vivo oxygen tension (P = 0.05) and with higher synovial 4-HNE cytoplasmic expression (P = 0.04). Synovial expression of CytcO II correlated with in vivo tPO(2) levels (P = 0.03), and levels were lower in patients with tPO(2) <20 mm Hg (P < 0.05). In vitro levels of mtDNA mutations, ROS, mitochondrial membrane potential, 8-oxo-dG, and 4-HNE were higher in synoviocytes exposed to 1% hypoxia (P < 0.05); all of these increased levels were rescued by SOD and DMOG and, with the exception of ROS, by NAC. CONCLUSION: These findings demonstrate that hypoxia-induced mitochondrial dysfunction drives

  9. Hypoxia-Inducible Factor 1 Is an Inductor of Transcription Factor Activating Protein 2 Epsilon Expression during Chondrogenic Differentiation

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    Stephan Niebler

    2015-01-01

    Full Text Available The transcription factor AP-2ε (activating enhancer-binding protein epsilon is expressed in cartilage of humans and mice. However, knowledge about regulatory mechanisms influencing AP-2ε expression is limited. Using quantitative real time PCR, we detected a significant increase in AP-2ε mRNA expression comparing initial and late stages of chondrogenic differentiation processes in vitro and in vivo. Interestingly, in these samples the expression pattern of the prominent hypoxia marker gene angiopoietin-like 4 (Angptl4 strongly correlated with that of AP-2ε suggesting that hypoxia might represent an external regulator of AP-2ε expression in mammals. In order to show this, experiments directly targeting the activity of hypoxia-inducible factor-1 (HIF1, the complex mediating responses to oxygen deprivation, were performed. While the HIF1-activating compounds 2,2′-dipyridyl and desferrioxamine resulted in significantly enhanced mRNA concentration of AP-2ε, siRNA against HIF1α led to a significantly reduced expression rate of AP-2ε. Additionally, we detected a significant upregulation of the AP-2ε mRNA level after oxygen deprivation. In sum, these different experimental approaches revealed a novel role for the HIF1 complex in the regulation of the AP-2ε gene in cartilaginous cells and underlined the important role of hypoxia as an important external regulatory stimulus during chondrogenic differentiation modulating the expression of downstream transcription factors.

  10. Role of hypoxia and hypoxia inducible factor in physiological and pathological conditions

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    Mozhgan Jahani

    2017-11-01

    Full Text Available Introduction: Organisms are exposed to oxygen deprivation (Hypoxia in various physiological and pathological conditions. There are different conserve evolutionary responses to counterview with this stress that primary transcriptional response to stress related to hypoxia is interceded by hypoxia-inducible factor (HIF-1 in mammals. This factor can regulate different genes that have essential roles in adaptation to this condition. In this review, the role of this factor in physiological and pathological conditions under hypoxic condition has been evaluated after examining structural features and regulation characteristics of HIF-1. Methods: First, articles related to the keywords of hypoxia and HIF-1 (from 1991-2016 were searched from valid databases such as Springer Link, Google Scholar, PubMed and Science direct. Then, the articles correlated with hypoxia, HIF-1 and their roles in physiological and pathological conditions (120 articles were searched and just 64 articles were selected for this study. Result: According to studies, there are different genes in cells and organs that can be regulated by HIF-1. Activation of genes expression by this protein occurs through its linkage to cis-acting of 50 base pair hypoxia response element (HRE region located in their promotor and enhancer. Depending on circumstances, activation of these genes can be beneficial or harmful. Conclusion: Activation of different genes in hypoxia by HIF-1 has different effects on physiological and pathological conditions. Therefore, HIF-1, as a hypoxia-inducible factor in hypoxic conditions, plays an essential role in the adaptation of cells and organs to changes related to the presence of oxygen.

  11. Upregulated copper transporters in hypoxia-induced pulmonary hypertension.

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    Adriana M Zimnicka

    Full Text Available Pulmonary vascular remodeling and increased arterial wall stiffness are two major causes for the elevated pulmonary vascular resistance and pulmonary arterial pressure in patients and animals with pulmonary hypertension. Cellular copper (Cu plays an important role in angiogenesis and extracellular matrix remodeling; increased Cu in vascular smooth muscle cells has been demonstrated to be associated with atherosclerosis and hypertension in animal experiments. In this study, we show that the Cu-uptake transporter 1, CTR1, and the Cu-efflux pump, ATP7A, were both upregulated in the lung tissues and pulmonary arteries of mice with hypoxia-induced pulmonary hypertension. Hypoxia also significantly increased expression and activity of lysyl oxidase (LOX, a Cu-dependent enzyme that causes crosslinks of collagen and elastin in the extracellular matrix. In vitro experiments show that exposure to hypoxia or treatment with cobalt (CoCl2 also increased protein expression of CTR1, ATP7A, and LOX in pulmonary arterial smooth muscle cells (PASMC. In PASMC exposed to hypoxia or treated with CoCl2, we also confirmed that the Cu transport is increased using 64Cu uptake assays. Furthermore, hypoxia increased both cell migration and proliferation in a Cu-dependent manner. Downregulation of hypoxia-inducible factor 1α (HIF-1α with siRNA significantly attenuated hypoxia-mediated upregulation of CTR1 mRNA. In summary, the data from this study indicate that increased Cu transportation due to upregulated CTR1 and ATP7A in pulmonary arteries and PASMC contributes to the development of hypoxia-induced pulmonary hypertension. The increased Cu uptake and elevated ATP7A also facilitate the increase in LOX activity and thus the increase in crosslink of extracellular matrix, and eventually leading to the increase in pulmonary arterial stiffness.

  12. Interspecific differences in hypoxia-induced gill remodeling in carp.

    Science.gov (United States)

    Dhillon, Rashpal S; Yao, Lili; Matey, Victoria; Chen, Bo-Jian; Zhang, An-Jie; Cao, Zhen-Dong; Fu, Shi-Jian; Brauner, Colin J; Wang, Yuxiang S; Richards, Jeffrey G

    2013-01-01

    The gills of many fish, but in particular those of crucian carp (Carassius carassius) and goldfish (Carassius auratus), are capable of extensive remodeling in response to changes in oxygen (O2), temperature, and exercise. In this study, we investigated the interspecific variation in hypoxia-induced gill modeling and hypoxia tolerance in 10 closely related groups of cyprinids (nine species, with two strains of Cyprinus carpio). There was significant variation in hypoxia tolerance, measured as the O2 tension (P(O2)) at which fish lost equilibrium (LOEcrit), among the 10 groups of carp. In normoxia, there was a significant, phylogenetically independent relationship between mass-specific gill surface area and LOEcrit, with the more hypoxia-tolerant carp having smaller gills than their less hypoxia-tolerant relatives. All groups of carp, except the Chinese bream (Megalobrama pellegrini), increased mass-specific gill surface area in response to 48 h of exposure to hypoxia (0.7 kPa) through reductions in the interlamellar cell mass (ILCM) volume. The magnitude of the hypoxia-induced reduction in the ILCM was negatively correlated with LOEcrit (and thus positively correlated with hypoxia tolerance), independent of phylogeny. The hypoxia-induced changes in gill morphology resulted in reduced variation in mass-specific gill surface area among species and eliminated the relationship between LOEcrit and mass-specific gill surface area. While behavioral responses to hypoxia differed among the carp groups, there were no significant relationships between hypoxia tolerance and the Po2 at which aquatic surface respiration (ASR) was initiated or the total number of ASR events observed during progressive hypoxia. Our results are the first to show that the extent of gill remodeling in cyprinids is associated with hypoxia tolerance in a phylogenetically independent fashion.

  13. Current advances in the novel functions of hypoxia-inducible factor and prolyl hydroxylase in invertebrates.

    Science.gov (United States)

    Wang, L; Cui, S; Ma, L; Kong, L; Geng, X

    2015-12-01

    Oxygen is essential for aerobic life, and hypoxia has very severe consequences. Organisms need to overcome low oxygen levels to maintain biological functions during normal development and in disease states. The mechanism underlying the hypoxic response has been widely investigated in model animals such as Drosophila melanogaster and Caenorhabditis elegans. Hypoxia-inducible factor (HIF), a key gene product in the response to oxygen deprivation, is primarily regulated by prolyl hydroxylase domain enzymes (PHDs). However, recent findings have uncovered novel HIF-independent functions of PHDs. This review provides an overview of how invertebrates are able to sustain hypoxic damages, and highlights some recent discoveries in the regulation of cellular signalling by PHDs. Given that some core genes and major pathways are evolutionarily conserved, these research findings could provide insight into oxygen-sensitive signalling in mammals, and have biomedical implications for human diseases. © 2015 The Royal Entomological Society.

  14. Rv1894c Is a Novel Hypoxia-Induced Nitronate Monooxygenase Required for Mycobacterium tuberculosis Virulence

    Science.gov (United States)

    Klinkenberg, Lee G.; Karakousis, Petros C.

    2013-01-01

    Tuberculosis is difficult to cure, requiring a minimum of 6 months of treatment with multiple antibiotics. Small numbers of organisms are able to tolerate the antibiotics and persist in the lungs of infected humans, but they still require some metabolic activity to survive. We studied the role of the hypoxia-induced Rv1894c gene in Mycobacterium tuberculosis virulence in guinea pigs, which develop hypoxic, necrotic granulomas histologically resembling those in humans and found this gene to be necessary for full bacillary growth and survival. We characterized the function of the encoded enzyme as a nitronate monooxygenase, which is needed to prevent the buildup of toxic products during hypoxic metabolism and is negatively regulated by the transcriptional repressor KstR. Future studies will focus on developing small-molecule inhibitors that target Rv1894c and its homologs, with the goal of killing persistent bacteria, thereby shortening the time needed to treat tuberculosis. PMID:23408846

  15. Hypoxia-inducible factor-1α induces multidrug resistance protein in colon cancer

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    Lv Y

    2015-07-01

    Full Text Available Yingqian Lv, Shan Zhao, Jinzhu Han, Likang Zheng, Zixin Yang, Li Zhao Department of Oncology, The Second Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, People’s Republic of China Abstract: Multidrug resistance is the major cause of chemotherapy failure in many solid tumors, including colon cancer. Hypoxic environment is a feature for all solid tumors and is important for the development of tumor resistance to chemotherapy. Hypoxia-inducible factor (HIF-1α is the key transcription factor that mediates cellular response to hypoxia. HIF-1α has been shown to play an important role in tumor resistance; however, the mechanism is still not fully understood. Here, we found that HIF-1α and the drug resistance-associated gene multidrug resistance associated protein 1 (MRP1 were induced by treatment of colon cancer cells with the hypoxia-mimetic agent cobalt chloride. Inhibition of HIF-1α by RNA interference and dominant-negative protein can significantly reduce the induction of MRP1 by hypoxia. Bioinformatics analysis showed that a hypoxia response element is located at -378 to -373 bp upstream of the transcription start site of MRP1 gene. Luciferase reporter assay combined with mutation analysis confirmed that this element is essential for hypoxia-mediated activation of MRP gene. Furthermore, RNA interference revealed that HIF-1α is necessary for this hypoxia-driven activation of MRP1 promoter. Importantly, chromatin immunoprecipitation analysis demonstrated that HIF-1α could directly bind to this HRE site in vivo. Together, these data suggest that MRP1 is a downstream target gene of HIF-1α, which provides a potential novel mechanism for HIF-1α-mediated drug resistance in colon cancer and maybe other solid tumors as well. Keywords: hypoxia, hypoxia-inducible factor-1α, multidrug resistance associated protein, transcriptional regulation, chemotherapy tolerance

  16. Role of hypoxia-inducible factor-1 in transcriptional activation of ceruloplasmin by iron deficiency

    Science.gov (United States)

    Mukhopadhyay, C. K.; Mazumder, B.; Fox, P. L.

    2000-01-01

    A role of the copper protein ceruloplasmin (Cp) in iron metabolism is suggested by its ferroxidase activity and by the tissue iron overload in hereditary Cp deficiency patients. In addition, plasma Cp increases markedly in several conditions of anemia, e.g. iron deficiency, hemorrhage, renal failure, sickle cell disease, pregnancy, and inflammation. However, little is known about the cellular and molecular mechanism(s) involved. We have reported that iron chelators increase Cp mRNA expression and protein synthesis in human hepatocarcinoma HepG2 cells. Furthermore, we have shown that the increase in Cp mRNA is due to increased rate of transcription. We here report the results of new studies designed to elucidate the molecular mechanism underlying transcriptional activation of Cp by iron deficiency. The 5'-flanking region of the Cp gene was cloned from a human genomic library. A 4774-base pair segment of the Cp promoter/enhancer driving a luciferase reporter was transfected into HepG2 or Hep3B cells. Iron deficiency or hypoxia increased luciferase activity by 5-10-fold compared with untreated cells. Examination of the sequence showed three pairs of consensus hypoxia-responsive elements (HREs). Deletion and mutation analysis showed that a single HRE was necessary and sufficient for gene activation. The involvement of hypoxia-inducible factor-1 (HIF-1) was shown by gel-shift and supershift experiments that showed HIF-1alpha and HIF-1beta binding to a radiolabeled oligonucleotide containing the Cp promoter HRE. Furthermore, iron deficiency (and hypoxia) did not activate Cp gene expression in Hepa c4 hepatoma cells deficient in HIF-1beta, as shown functionally by the inactivity of a transfected Cp promoter-luciferase construct and by the failure of HIF-1 to bind the Cp HRE in nuclear extracts from these cells. These results are consistent with in vivo findings that iron deficiency increases plasma Cp and provides a molecular mechanism that may help to understand these

  17. Hypoxia-Induced Oxidative Stress Modulation with Physical Activity

    Science.gov (United States)

    Debevec, Tadej; Millet, Grégoire P.; Pialoux, Vincent

    2017-01-01

    Increased oxidative stress, defined as an imbalance between prooxidants and antioxidants, resulting in molecular damage and disruption of redox signaling, is associated with numerous pathophysiological processes and known to exacerbate chronic diseases. Prolonged systemic hypoxia, induced either by exposure to terrestrial altitude or a reduction in ambient O2 availability is known to elicit oxidative stress and thereby alter redox balance in healthy humans. The redox balance modulation is also highly dependent on the level of physical activity. For example, both high-intensity exercise and inactivity, representing the two ends of the physical activity spectrum, are known to promote oxidative stress. Numerous to-date studies indicate that hypoxia and exercise can exert additive influence upon redox balance alterations. However, recent evidence suggests that moderate physical activity can attenuate altitude/hypoxia-induced oxidative stress during long-term hypoxic exposure. The purpose of this review is to summarize recent findings on hypoxia-related oxidative stress modulation by different activity levels during prolonged hypoxic exposures and examine the potential mechanisms underlying the observed redox balance changes. The paper also explores the applicability of moderate activity as a strategy for attenuating hypoxia-related oxidative stress. Moreover, the potential of such moderate intensity activities used to counteract inactivity-related oxidative stress, often encountered in pathological, elderly and obese populations is also discussed. Finally, future research directions for investigating interactive effects of altitude/hypoxia and exercise on oxidative stress are proposed. PMID:28243207

  18. Hypoxia-Induced Oxidative Stress Modulation with Physical Activity.

    Science.gov (United States)

    Debevec, Tadej; Millet, Grégoire P; Pialoux, Vincent

    2017-01-01

    Increased oxidative stress, defined as an imbalance between prooxidants and antioxidants, resulting in molecular damage and disruption of redox signaling, is associated with numerous pathophysiological processes and known to exacerbate chronic diseases. Prolonged systemic hypoxia, induced either by exposure to terrestrial altitude or a reduction in ambient O2 availability is known to elicit oxidative stress and thereby alter redox balance in healthy humans. The redox balance modulation is also highly dependent on the level of physical activity. For example, both high-intensity exercise and inactivity, representing the two ends of the physical activity spectrum, are known to promote oxidative stress. Numerous to-date studies indicate that hypoxia and exercise can exert additive influence upon redox balance alterations. However, recent evidence suggests that moderate physical activity can attenuate altitude/hypoxia-induced oxidative stress during long-term hypoxic exposure. The purpose of this review is to summarize recent findings on hypoxia-related oxidative stress modulation by different activity levels during prolonged hypoxic exposures and examine the potential mechanisms underlying the observed redox balance changes. The paper also explores the applicability of moderate activity as a strategy for attenuating hypoxia-related oxidative stress. Moreover, the potential of such moderate intensity activities used to counteract inactivity-related oxidative stress, often encountered in pathological, elderly and obese populations is also discussed. Finally, future research directions for investigating interactive effects of altitude/hypoxia and exercise on oxidative stress are proposed.

  19. Effect of Hachimijiogan against Renal Dysfunction and Involvement of Hypoxia-Inducible Factor-1α in the Remnant Kidney Model

    Directory of Open Access Journals (Sweden)

    Hiroshi Oka

    2011-01-01

    Full Text Available In chronic renal failure, hypoxia of renal tissue is thought to be the common final pathway leading to end-stage renal failure. In this study the effects of hachimijiogan, a Kampo formula, were studied with respect to hypoxia-inducible factor (HIF. Using remnant kidney rats, we studied the effects of hachimijiogan on renal function in comparison with angiotensin II receptor blocker. The result showed that oral administration of hachimijiogan for seven days suppressed urinary protein excretion and urinary 8-OHdG, a marker of antioxidant activity, equally as well as oral administration of candesartan cilexetil. In contrast, the protein volume of HIF-1α in the renal cortex was not increased in the candesartan cilexetil group, but that in the hachimijiogan group was increased. In immunohistochemical studies as well, the expression of HIF-1α of the high-dose hachimijiogan group increased compared to that of the control group. Vascular endothelial growth factor and glucose transporter 1, target genes of HIF-1α, were also increased in the hachimijiogan group. These results suggest that hachimijiogan produces a protective effect by a mechanism different from that of candesartan cilexetil.

  20. Muscle-specific expression of hypoxia-inducible factor in human skeletal muscle

    DEFF Research Database (Denmark)

    Mounier, Rémi; Pedersen, Bente Klarlund; Plomgaard, Peter

    2010-01-01

    fibres that possess unique patterns of protein and gene expression, producing different capillarization and energy metabolism systems. In this work, we analysed HIF-1alpha mRNA and protein expression related to the fibre-type composition in untrained human skeletal muscle by obtaining muscle biopsies......Skeletal muscle is well known to exhibit a high degree of plasticity depending on environmental changes, such as various oxygen concentrations. Studies of the oxygen-sensitive subunit alpha of hypoxia-inducible factor-1 (HIF-1) are difficult owing to the large variety of functionally diverse muscle......alpha mRNA and protein owing to their higher oxidative capacity. We have shown, in normoxic conditions, a higher HIF-1alpha protein expression in predominantly oxidative muscles than in predominantly glycolytic muscles. However, the HIF-1alpha mRNA expression pattern was not in agreement with the HIF-1...

  1. Hypoxia induced expression of endogenous markers in vitro is highly influenced by pH

    DEFF Research Database (Denmark)

    Sørensen, Brita Singers; Alsner, Jan; Overgaard, Jens

    2007-01-01

    BACKGROUND: Genes such as carbonic anhydrase IX (Ca9), glucose transporter 1 (Glut1), lactate dehydrogenase A (LDH-A), osteopontin (OPN) and lysyl oxidase (LOX) have been suggested as hypoxic markers, but inconsistent results suggest that factors other than oxygen influence their expression......Ha and FaDu(DD) cells Ca9 and LOX reached the highest level of expression at 1% oxygen. In FaDu(DD) cells, a pH of 6.5 had a medium suppression effect on the hypoxia induced expression of Ca9. pH 6.3 resulted in severe suppression of expression for Ca9 and LOX in both SiHa and FaDu(DD). Glut1 and LDH-A had...

  2. Hypoxia Inducible Factor-1α (HIF-1 α and its Role in Tumour Progression to Malignancy

    Directory of Open Access Journals (Sweden)

    Gaurav Mrinal Sharma

    2008-07-01

    Full Text Available Hypoxia is a condition in which an area of the body or a tissue is deprived of sufficient supply of oxygen. The lack of nutrients in a hypoxic tissue generally causes apoptosis but some cells are able to adapt to this hypoxic environment and resist apoptosis. This adaptation occurs as a result of gene activation. Hypoxia is a characteristic feature of many cancers and is the stimulus for overexpression of HIF-1α - a basic loop-helix PAS protein family subunit of HIF, which allows the cell to adapt and survive in hostile environment. The presence of hypoxia and HIF-1α is correlated with an increased risk of metastasis and techniques that can inhibit hypoxia inducible factor may be instrumental in finding a cure for cancer.

  3. Characterization and functional analysis of hypoxia-inducible factor HIF1α and its inhibitor HIF1αn in tilapia.

    Science.gov (United States)

    Li, Hong Lian; Gu, Xiao Hui; Li, Bi Jun; Chen, Xiao; Lin, Hao Ran; Xia, Jun Hong

    2017-01-01

    Hypoxia is a major cause of fish morbidity and mortality in the aquatic environment. Hypoxia-inducible factors are very important modulators in the transcriptional response to hypoxic stress. In this study, we characterized and conducted functional analysis of hypoxia-inducible factor HIF1α and its inhibitor HIF1αn in Nile tilapia (Oreochromis niloticus). By cloning and Sanger sequencing, we obtained the full length cDNA sequences for HIF1α (2686bp) and HIF1αn (1308bp), respectively. The CDS of HIF1α includes 15 exons encoding 768 amino acid residues and the CDS of HIF1αn contains 8 exons encoding 354 amino acid residues. The complete CDS sequences of HIF1α and HIF1αn cloned from tilapia shared very high homology with known genes from other fishes. HIF1α show differentiated expression in different tissues (brain, heart, gill, spleen, liver) and at different hypoxia exposure times (6h, 12h, 24h). HIF1αn expression level under hypoxia is generally increased (6h, 12h, 24h) and shows extremely highly upregulation in brain tissue under hypoxia. A functional determination site analysis in the protein sequences between fish and land animals identified 21 amino acid sites in HIF1α and 2 sites in HIF1αn as significantly associated sites (α = 0.05). Phylogenetic tree-based positive selection analysis suggested 22 sites in HIF1α as positively selected sites with a p-value of at least 95% for fish lineages compared to the land animals. Our study could be important for clarifying the mechanism of fish adaptation to aquatic hypoxia environment.

  4. AEG-1 is associated with hypoxia-induced hepatocellular carcinoma chemoresistance via regulating PI3K/AKT/HIF-1alpha/MDR-1 pathway.

    Science.gov (United States)

    Xie, Yong; Zhong, De-Wu

    2016-01-01

    Hypoxia is a common characteristic of hepatocellular carcinoma (HCC) associated with reduced response to chemotherapy, thus increasing the probability of tumor recurrence. Astrocyte elevated gene-1 (AEG-1) has been involved in a wide array of cancer progression including proliferation, chemoresistance, angiogenesis and metastasis, but its effect on HCC chemoresistance induced by hypoxia is unclear. In this study, expression of AEG-1 and multiple drug resistance (MDR-1) were examined in HCC using immunohistochemical staining and RT-PCR. Furthermore, their expression levels were detected in HCC HepG2 cells in normoxia or hypoxia via RT-PCR and Western blot assays. Specific shRNAs were used to silence AEG-1 expression in HepG2 cells. Results showed AEG-1 and MDR-1 expression were higher in HCC tissues than in adjacent normal tissues. Incubation of HepG2 cells in hypoxia increased expression of AEG-1 and MDR-1, compared to incubation in normoxia. Exposure to hypoxia blunted sensitivity of HepG2 cells to Adriamycin, 5-fluorouracil and cis-platinum, as evidenced by modest alterations in cell viability and apoptosis rate, however the sensitivity was elevated with AEG-1 knockdown. PI3K/AKT/HIF-1/MDR-1 pathway was attenuated following AEG-1 knockdown in hypoxia. Based on these data, it was suggested that AEG-1 is associated with hypoxia-induced hepatocellular carcinoma chemoresistance via regulating PI3K/AKT/HIF-1/MDR-1 pathway. This study uncovered a novel potential target for development of an effective therapy against hypoxia-induced HCC chemoresistance.

  5. Prolyl-hydroxylase inhibitor activating hypoxia-inducible transcription factors reduce levels of transplant arteriosclerosis in a murine aortic allograft model.

    Science.gov (United States)

    Heim, Christian; Bernhardt, Wanja; Jalilova, Sabina; Wang, Zhendi; Motsch, Benjamin; Ramsperger-Gleixner, Martina; Burzlaff, Nicolai; Weyand, Michael; Eckardt, Kai-Uwe; Ensminger, Stephan M

    2016-05-01

    The development of transplant arteriosclerosis, the hallmark feature of heart transplant rejection, is associated with a chronic immune response and also influenced by an initial injury to the graft through ischaemia and reperfusion. Hypoxia-inducible transcription factor (HIF)-1 pathway signalling has a protective effect against ischaemia-reperfusion injury and has already been demonstrated to ameliorate allograft nephropathy in previous animal studies. Therefore, the aim of this study was to investigate the effect of stabilization of hypoxia-inducible transcription factors with a prolyl-hydroxylase domain (PHD) inhibitor on transplant arteriosclerosis in an experimental aortic allograft model. MHC-class I mismatched C.B10-H2(b)/LilMcdJ donor thoracic aortas were heterotopically transplanted into the abdominal aorta of BALB/c mice. Donor animals received a single dose of the PHD inhibitor 2-(1-chloro-4-hydroxyisoquinoline-3-carboxamido) acetate (ICA) (40 mg/kg) or vehicle i.p. 4 h before transplantation. Intragraft HIF accumulation after ICA treatment was detected by immunohistochemistry before and after cold ischaemia (n = 5). Grafts were harvested 30 days after transplantation and analysed by histology (n = 7) and immunofluorescence (n = 7). In addition, intragraft mRNA expression for cytokines, adhesion molecules and growth factors was determined on Day 14 (n = 7). Donor preconditioning with ICA resulted in HIF accumulation in the aorta and induction of the HIF target genes vascular endothelial growth factor and transforming growth factor-beta. Vascular lesions were present in both experimental groups. However, there was significantly reduced intimal proliferation in preconditioned grafts when compared with vehicle controls [intimal proliferation 31.3 ± 8% (ICA) vs 55.3 ± 20% (control), P arteriosclerosis and allograft injury. Pharmaceutical inhibition of PHDs appears to be a very attractive strategy for organ preservation that deserves further clinical

  6. Hypoxia-induced metastasis model in embryonic zebrafish

    DEFF Research Database (Denmark)

    Rouhi, Pegah; Jensen, Lasse D.; Cao, Ziquan

    2010-01-01

    Hypoxia facilitates tumor invasion and metastasis by promoting neovascularization and co-option of tumor cells in the peritumoral vasculature, leading to dissemination of tumor cells into the circulation. However, until recently, animal models and imaging technology did not enable monitoring...... of the early events of tumor cell invasion and dissemination in living animals. We recently developed a zebrafish metastasis model to dissect the detailed events of hypoxia-induced tumor cell invasion and metastasis in association with angiogenesis at the single-cell level. In this model, fluorescent Di......I-labeled human or mouse tumor cells are implanted into the perivitelline cavity of 48-h-old zebrafish embryos, which are subsequently placed in hypoxic water for 3 d. Tumor cell invasion, metastasis and pathological angiogenesis are detected under fluorescent microscopy in the living fish. The average...

  7. Hypoxia-inducible factor 1 and breast cancer metastasis.

    Science.gov (United States)

    Liu, Zhao-Ji; Semenza, Gregg L; Zhang, Hua-Feng

    2015-01-01

    Accumulating evidence has shown that the hypoxic microenvironment, which is critical during cancer development, plays a key role in regulating breast cancer progression and metastasis. The effects of hypoxia-inducible factor 1 (HIF-1), a master regulator of the hypoxic response, have been extensively studied during these processes. In this review, we focus on the roles of HIF-1 in regulating breast cancer cell metastasis, specifically its effects on multiple key steps of metastasis, such as epithelial-mesenchymal transition (EMT), invasion, extravasation, and metastatic niche formation. We also discuss the roles of HIF-1-regulated non-coding RNAs in breast cancer metastasis, and therapeutic opportunities for breast cancer through targeting the HIF-1 pathway.

  8. Role of hypoxia-inducible factors in acute kidney injury.

    Science.gov (United States)

    Andringa, Kelly K; Agarwal, Anupam

    2014-01-01

    Oxygen is vital to mammalian survival. Oxygen deprivation, defined as hypoxia, elicits adaptive responses in cells and tissues, a process regulated by proteins known as hypoxia-inducible factors (HIF). Animal studies have provided compelling data to demonstrate a pivotal role for the HIF pathway in the pathogenesis of acute kidney injury (AKI) that have led to initial human clinical trials examining this pathway in ischemia-reperfusion injury in various organ systems, including the kidney. HIF are master regulators and mediate adaptive responses to low oxygen in tissues and cells. This review will summarize recent key advances in the field highlighting preclinical and clinical studies relevant to the HIF pathway in the pathophysiology of AKI. 2014 S. Karger AG, Basel.

  9. Retinal hypoxia induces vascular endothelial growth factor through induction of estrogen-related receptor γ

    Energy Technology Data Exchange (ETDEWEB)

    Do, Ji Yeon; Choi, Young Keun [Leading-edge Research Center for Drug Discovery and Development for Diabetes and Metabolic Disease, Kyungpook National University School of Medicine, Kyungpook National University, Daegu (Korea, Republic of); Kook, Hyun [Department of Pharmacology, Chonnam National University Medical School, Gwangju (Korea, Republic of); Suk, Kyoungho [Department of Pharmacology, Brain Science & Engineering Institute, Kyungpook National University School of Medicine, Daegu (Korea, Republic of); Lee, In-Kyu [Leading-edge Research Center for Drug Discovery and Development for Diabetes and Metabolic Disease, Kyungpook National University School of Medicine, Kyungpook National University, Daegu (Korea, Republic of); Division of Endocrinology and Metabolism, Department of Internal Medicine, Research Institute of Aging and Metabolism, Kyungpook National University School of Medicine, Daegu (Korea, Republic of); Park, Dong Ho, E-mail: sarasate2222@gmail.com [Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu (Korea, Republic of)

    2015-05-01

    Ischemic retinopathies causing overexpression of pro-angiogenic factors, including vascular endothelial growth factor (VEGF), are the most common cause of blindness. Thus, understanding the pathophysiology of targetable pathways that regulate retinal VEGF is of great interest. A conserved binding site for estrogen-related receptor γ (ERRγ) has been identified in the promoter of the Vegfa gene. ERRγ is a constitutively active orphan nuclear receptor and its expression is increased by hypoxic stimuli in metabolically active tissues. This study evaluated the role of ERRγ in the ischemic retina and the anti-VEGF potential of GSK5182, a selective inverse agonist of ERRγ. In an oxygen-induced retinopathy (OIR) mouse model, immunohistochemistry showed significantly increased ERRγ expression in the ganglion cell layer at postnatal day (P) 17. In a ganglion cell line (RGC-5), mRNA and protein levels of ERRγ were increased by desferrioxamine treatment and hypoxic conditions (1% O{sub 2}). Transient transfection of RGC-5 cells revealed that ERRγ regulated Vegfa expression and this was inhibited by GSK5182. Intravitreal injection of GSK5182 into the OIR model at P14 inhibited retinal Vegfa mRNA expression at P17. GSK5182 suppresses hypoxia-induced VEGF expression via ERRγ; therefore, ERRγ could be a treatment target for ischemic retinopathies. - Highlights: • OIR mice exhibited increased ERRγ expression in the ganglion cell layer. • Hypoxia-induced ERRγ expression was observed in retinal ganglion cells. • ERRγ overexpression increased VEGFA expression in retinal ganglion cells. • An ERRγ inverse agonist suppressed VEGFA expression in retinal ganglion cells. • Intravitreal injection of an ERRγ inverse agonist suppressed VEGFA in OIR mice.

  10. Overexpression of ERβ is sufficient to inhibit hypoxia-inducible factor-1 transactivation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Choa; Lee, YoungJoo, E-mail: yjlee@sejong.ac.kr

    2014-07-18

    Highlights: • We examined the effect of ERβ specific ligand on HIF-1 inhibition. • DPN down-regulates the ARNT protein levels in PC3 cells. • DPN did not show additional effect in ERβ transfected MCF-7 cells. • Our study shows that unliganded ERβ is sufficient to inhibit HIF-1 in systems of overexpression. - Abstract: Estrogen receptor (ER) β is predicted to play an important role in the prevention of breast cancer development and progression. We have previously shown that ERβ suppresses hypoxia inducible factor (HIF)-1-mediated transcription through aryl hydrocarbon receptor nuclear translocator (ARNT) degradation via ubiquitination processes. In this study, we attempted to examine the effect of ERβ specific ligand on HIF-1 inhibition in ERβ positive PC3 cells and ERβ transfected MCF-7 cells. ERβ specific agonist diarylpropionitrile (DPN) stimulated estrogen response element (ERE)-luciferase activity in a similar fashion to estradiol in PC3 cells. We observed that DPN down-regulates the ARNT protein levels leading to an attenuation of hypoxia-induced hypoxia response element (HRE)-driven luciferase reporter gene activation in PC3 cells. Treatment of DPN reduced vascular endothelial growth factor (VEGF) expression and co-treatment with ERβ specific antagonist PHTPP abrogated the effect in PC3 cells. We then examined the effect of DPN in ERβ transfected MCF-7 cells. HIF-1 transcriptional activity repression by ERβ was not further reduced by DPN, as examined by HRE-driven luciferase assays. Expression of ERβ significantly decreased VEGF secretion and ARNT expression under hypoxic conditions. However, DPN did not additionally affect this suppression in MCF-7 cells transfected with ERβ. This result shows that unliganded ERβ is sufficient to inhibit HIF-1 in systems of overexpression.

  11. Hypoxia-inducible factor-1α(Pro-582-Ser) polymorphism prevents iron deprivation in healthy blood donors.

    Science.gov (United States)

    Torti, Lorenza; Teofili, Luciana; Capodimonti, Sara; Nuzzolo, Eugenia R; Iachininoto, Maria Grazia; Massini, Giuseppina; Coluzzi, Serelina; Tafuri, Agostino; Fiorin, Francesco; Girelli, Gabriella; Zini, Gina; Larocca, Luigi M

    2013-10-01

    Frequent blood loss induces progressive depletion of iron stores, leading to iron deficiency and, ultimately, to overt iron-deficient anaemia. The erythropoietin-mediated bone marrow response to anaemia is under the control of hypoxia-inducible factors (HIF), the master regulators of oxygen and iron homeostasis. Since the HIF-1α(Pro-582-Ser) variant is associated with elevated trans-activation capacity of hypoxia responsive elements of target genes, we investigated whether the HIF-1α(Pro-582-Ser) polymorphism might influence the response to repeated blood withdrawals. Using polymerase chain reaction analysis and DNA sequencing, we retrospectively investigated the presence of HIF-1α(Pro-582-Ser) in a series of 163 blood donors. Haematological findings, serum ferritin levels and frequency of donations were compared according to the mutational status of the HIF-1α gene. We found that male carriers of the HIF-1α(Pro-582-Ser) polymorphism had higher haemoglobin and ferritin levels than individuals homozygous for the wild-type allele. Moreover, the HIF-1α(Pro-582-Ser) polymorphism protected regular blood donors from developing iron deficiency and anaemia and predicted uninterrupted donation activity. These findings show for the first time that the HIF-1α(Pro-582-Ser) polymorphism significantly affects red blood cell and iron homeostasis after blood loss, conferring to male carriers a resistance to anaemia. Regarding the female gender, large series of individuals should be investigated to establish whether there is an effect of the HIF-1α(Pro-582-Ser) polymorphism in this population. Although these data need to be confirmed in prospective studies, they could have important implications in blood donor selection and donation procedures.

  12. Thiamine deficiency activates hypoxia inducible factor-1α to facilitate pro-apoptotic responses in mouse primary astrocytes.

    Directory of Open Access Journals (Sweden)

    Kristy Zera

    Full Text Available Thiamine is an essential enzyme cofactor required for proper metabolic function and maintenance of metabolism and energy production in the brain. In developed countries, thiamine deficiency (TD is most often manifested following chronic alcohol consumption leading to impaired mitochondrial function, oxidative stress, inflammation and excitotoxicity. These biochemical lesions result in apoptotic cell death in both neurons and astrocytes. Comparable histological injuries in patients with hypoxia/ischemia and TD have been described in the thalamus and mammillary bodies, suggesting a congruency between the cellular responses to these stresses. Consistent with hypoxia/ischemia, TD stabilizes and activates Hypoxia Inducible Factor-1α (HIF-1α under physiological oxygen levels. However, the role of TD-induced HIF-1α in neurological injury is currently unknown. Using Western blot analysis and RT-PCR, we have demonstrated that TD induces HIF-1α expression and activity in primary mouse astrocytes. We observed a time-dependent increase in mRNA and protein expression of the pro-apoptotic and pro-inflammatory HIF-1α target genes MCP1, BNIP3, Nix and Noxa during TD. We also observed apoptotic cell death in TD as demonstrated by PI/Annexin V staining, TUNEL assay, and Cell Death ELISA. Pharmacological inhibition of HIF-1α activity using YC1 and thiamine repletion both reduced expression of pro-apoptotic HIF-1α target genes and apoptotic cell death in TD. These results demonstrate that induction of HIF-1α mediated transcriptional up-regulation of pro-apoptotic/inflammatory signaling contributes to astrocyte cell death during thiamine deficiency.

  13. Thiamine deficiency activates hypoxia inducible factor-1α to facilitate pro-apoptotic responses in mouse primary astrocytes.

    Science.gov (United States)

    Zera, Kristy; Zastre, Jason

    2017-01-01

    Thiamine is an essential enzyme cofactor required for proper metabolic function and maintenance of metabolism and energy production in the brain. In developed countries, thiamine deficiency (TD) is most often manifested following chronic alcohol consumption leading to impaired mitochondrial function, oxidative stress, inflammation and excitotoxicity. These biochemical lesions result in apoptotic cell death in both neurons and astrocytes. Comparable histological injuries in patients with hypoxia/ischemia and TD have been described in the thalamus and mammillary bodies, suggesting a congruency between the cellular responses to these stresses. Consistent with hypoxia/ischemia, TD stabilizes and activates Hypoxia Inducible Factor-1α (HIF-1α) under physiological oxygen levels. However, the role of TD-induced HIF-1α in neurological injury is currently unknown. Using Western blot analysis and RT-PCR, we have demonstrated that TD induces HIF-1α expression and activity in primary mouse astrocytes. We observed a time-dependent increase in mRNA and protein expression of the pro-apoptotic and pro-inflammatory HIF-1α target genes MCP1, BNIP3, Nix and Noxa during TD. We also observed apoptotic cell death in TD as demonstrated by PI/Annexin V staining, TUNEL assay, and Cell Death ELISA. Pharmacological inhibition of HIF-1α activity using YC1 and thiamine repletion both reduced expression of pro-apoptotic HIF-1α target genes and apoptotic cell death in TD. These results demonstrate that induction of HIF-1α mediated transcriptional up-regulation of pro-apoptotic/inflammatory signaling contributes to astrocyte cell death during thiamine deficiency.

  14. Mammalian target of rapamycin complex 1 activation sensitizes human glioma cells to hypoxia-induced cell death.

    Science.gov (United States)

    Thiepold, Anna-Luisa; Lorenz, Nadja I; Foltyn, Martha; Engel, Anna L; Divé, Iris; Urban, Hans; Heller, Sonja; Bruns, Ines; Hofmann, Ute; Dröse, Stefan; Harter, Patrick N; Mittelbronn, Michel; Steinbach, Joachim P; Ronellenfitsch, Michael W

    2017-10-01

    Glioblastomas are characterized by fast uncontrolled growth leading to hypoxic areas and necrosis. Signalling from EGFR via mammalian target of rapamycin complex 1 (mTORC1) is a major driver of cell growth and proliferation and one of the most commonly altered signalling pathways in glioblastomas. Therefore, epidermal growth factor receptor and mTORC1 signalling are plausible therapeutic targets and clinical trials with inhibitors are in progress. However, we have previously shown that epidermal growth factor receptor and mTORC1 inhibition triggers metabolic changes leading to adverse effects under the conditions of the tumour microenvironment by protecting from hypoxia-induced cell death. We hypothesized that conversely mTORC1 activation sensitizes glioma cells to hypoxia-induced cell death. As a model for mTORC1 activation we used gene suppression of its physiological inhibitor TSC2 (TSC2sh). TSC2sh glioma cells showed increased sensitivity to hypoxia-induced cell death that was accompanied by an earlier ATP depletion and an increase in reactive oxygen species. There was no difference in extracellular glucose consumption but an altered intracellular metabolic profile with an increase of intermediates of the pentose phosphate pathway. Mechanistically, mTORC1 upregulated the first and rate limiting enzyme of the pentose phosphate pathway, G6PD. Furthermore, an increase in oxygen consumption in TSC2sh cells was detected. This appeared to be due to higher transcription rates of genes involved in mitochondrial respiratory function including PPARGC1A and PPARGC1B (also known as PGC-1α and -β). The finding that mTORC1 activation causes an increase in oxygen consumption and renders malignant glioma cells susceptible to hypoxia and nutrient deprivation could help identify glioblastoma patient cohorts more likely to benefit from hypoxia-inducing therapies such as the VEGFA-targeting antibody bevacizumab in future clinical evaluations. © The Author (2017). Published by

  15. ACLY and ACC1 Regulate Hypoxia-Induced Apoptosis by Modulating ETV4 via α-ketoglutarate.

    Directory of Open Access Journals (Sweden)

    Melissa M Keenan

    2015-10-01

    Full Text Available In order to propagate a solid tumor, cancer cells must adapt to and survive under various tumor microenvironment (TME stresses, such as hypoxia or lactic acidosis. To systematically identify genes that modulate cancer cell survival under stresses, we performed genome-wide shRNA screens under hypoxia or lactic acidosis. We discovered that genetic depletion of acetyl-CoA carboxylase (ACACA or ACC1 or ATP citrate lyase (ACLY protected cancer cells from hypoxia-induced apoptosis. Additionally, the loss of ACLY or ACC1 reduced levels and activities of the oncogenic transcription factor ETV4. Silencing ETV4 also protected cells from hypoxia-induced apoptosis and led to remarkably similar transcriptional responses as with silenced ACLY or ACC1, including an anti-apoptotic program. Metabolomic analysis found that while α-ketoglutarate levels decrease under hypoxia in control cells, α-ketoglutarate is paradoxically increased under hypoxia when ACC1 or ACLY are depleted. Supplementation with α-ketoglutarate rescued the hypoxia-induced apoptosis and recapitulated the decreased expression and activity of ETV4, likely via an epigenetic mechanism. Therefore, ACC1 and ACLY regulate the levels of ETV4 under hypoxia via increased α-ketoglutarate. These results reveal that the ACC1/ACLY-α-ketoglutarate-ETV4 axis is a novel means by which metabolic states regulate transcriptional output for life vs. death decisions under hypoxia. Since many lipogenic inhibitors are under investigation as cancer therapeutics, our findings suggest that the use of these inhibitors will need to be carefully considered with respect to oncogenic drivers, tumor hypoxia, progression and dormancy. More broadly, our screen provides a framework for studying additional tumor cell stress-adaption mechanisms in the future.

  16. Expression profiling of laser-microdissected intrapulmonary arteries in hypoxia-induced pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Ziegler Andreas

    2005-09-01

    Full Text Available Abstract Background Chronic hypoxia influences gene expression in the lung resulting in pulmonary hypertension and vascular remodelling. For specific investigation of the vascular compartment, laser-microdissection of intrapulmonary arteries was combined with array profiling. Methods and Results Analysis was performed on mice subjected to 1, 7 and 21 days of hypoxia (FiO2 = 0.1 using nylon filters (1176 spots. Changes in the expression of 29, 38, and 42 genes were observed at day 1, 7, and 21, respectively. Genes were grouped into 5 different classes based on their time course of response. Gene regulation obtained by array analysis was confirmed by real-time PCR. Additionally, the expression of the growth mediators PDGF-B, TGF-β, TSP-1, SRF, FGF-2, TIE-2 receptor, and VEGF-R1 were determined by real-time PCR. At day 1, transcription modulators and ion-related proteins were predominantly regulated. However, at day 7 and 21 differential expression of matrix producing and degrading genes was observed, indicating ongoing structural alterations. Among the 21 genes upregulated at day 1, 15 genes were identified carrying potential hypoxia response elements (HREs for hypoxia-induced transcription factors. Three differentially expressed genes (S100A4, CD36 and FKBP1a were examined by immunohistochemistry confirming the regulation on protein level. While FKBP1a was restricted to the vessel adventitia, S100A4 and CD36 were localised in the vascular tunica media. Conclusion Laser-microdissection and array profiling has revealed several new genes involved in lung vascular remodelling in response to hypoxia. Immunohistochemistry confirmed regulation of three proteins and specified their localisation in vascular smooth muscle cells and fibroblasts indicating involvement of different cells types in the remodelling process. The approach allows deeper insight into hypoxic regulatory pathways specifically in the vascular compartment of this complex organ.

  17. Expression of hypoxia-inducible transcription factors in developing human and rat kidneys.

    Science.gov (United States)

    Bernhardt, W M; Schmitt, R; Rosenberger, C; Münchenhagen, P M; Gröne, H-J; Frei, U; Warnecke, C; Bachmann, S; Wiesener, M S; Willam, C; Eckardt, K-U

    2006-01-01

    Early kidney development is associated with the coordinated branching of the renal tubular and vascular system and hypoxia has been proposed to be a major regulatory factor in this process. Under low oxygen levels, the hypoxia-inducible transcription factor (HIF) regulates the expression of genes involved in angiogenesis, erythropoiesis and glycolysis. To investigate the role of HIF in kidney development, we analyzed the temporal and spatial expression of the oxygen regulated HIF-1alpha and -2alpha subunits at different stages of rat and human kidney development. Using double-staining procedures, localization of the HIF target geneproducts vascular endothelial growth factor (VEGF) and endoglin was studied in relation to HIFalpha. In both species, we found marked nuclear expression of HIF-1alpha in medullary and cortical collecting ducts and in glomerular cells. In contrast, HIF-2alpha was expressed in interstitial and peritubular cells podocytes of the more mature glomeruli. After completion of glomerulogenesis and nephrogenesis, HIF-1alpha and -2alpha were no longer detectable. The HIF-target gene VEGF colocalized with HIF-1alpha protein in glomeruli and medullary collecting ducts. HIF-2alpha colocalized with the endothelium-associated angiogenic factor, endoglin. Both HIFalpha isoforms are activated in the developing kidney in a cell-specific and temporally controlled manner, indicating a regulatory role of oxygen tension in nephrogenesis. HIF-1alpha seems to be primarily involved in tubulogenesis and HIF-2alpha in renal vasculogenesis. Both isoforms are found in glomerulogenesis, potentially having synergistic effects.

  18. Resistance to hypoxia-induced, BNIP3-mediated cell death contributes to an increase in a CD133-positive cell population in human glioblastomas in vitro.

    Science.gov (United States)

    Kahlert, Ulf Dietrich; Maciaczyk, Donata; Dai, Fangping; Claus, Rainer; Firat, Elke; Doostkam, Soroush; Bogiel, Tomasz; Carro, Maria Stella; Döbrössy, Mate; Herold-Mende, Christel; Niedermann, Gabriele; Prinz, Marco; Nikkhah, Guido; Maciaczyk, Jaroslaw

    2012-12-01

    In addition to intrinsic regulatory mechanisms, brain tumor stemlike cells (BTSCs), a small subpopulation of malignant glial tumor-derived cells, are influenced by environmental factors. Previous reports showed that lowering oxygen tension induced an increase of BTSCs expressing CD133 and other stem cell-related genes and more pronounced clonogenic capacity in vitro. We investigated the mechanisms responsible for hypoxia-dependent induction of CD133-positive BTSCs in glioblastomas. We confirmed that cultures exposed to lowered oxygen levels showed a severalfold increase of CD133-positive BTSCs. Both the increase of CD133-positive cells and deceleration of the growth kinetics were reversible after transfer to normoxic conditions. Exposure to hypoxia induced BNIP3 (BCL2/adenovirus E1B 19-kDa protein-interacting protein 3)-dependent apoptosis preferentially in CD133-negative cells. In contrast, CD133-positive cells proved to be more resistant to hypoxia-induced programmed cell death. Application of the demethylating agent 5'-azacitidine resulted in an increase of BNIP3 expression levels in CD133-positive cells. Thus, epigenetic modifications led to their better survival in lowered oxygen tension. Moreover, the, hypoxia-induced increase of CD133-positive cells was inhibited after 5'-azacitidine treatment. These results suggest the possible efficacy of a novel therapy for glioblastoma focused on eradication of BTSCs by modifications of epigenetic regulation of gene expression.

  19. [High-altitude hypoxia induces disorders of the brain-endocrine-immune network through activation of corticotropin-releasing factor and its type-1 receptors].

    Science.gov (United States)

    Chen, Xue-Qun; Kong, Fan-Ping; Zhao, Yang; Du, Ji-Zeng

    2012-11-01

    High-altitude hypoxia can induce physiological dysfunction and mountain sickness, but the underlying mechanism is not fully understood. Corticotrophin-releasing factor (CRF) and CRF type-i receptors (CRFR1) are members of the CRF family and the essential controllers of the physiological activity of the hypothalamo-pituitary-adrenal (HPA) axis and modulators of endocrine and behavioral activity in response to various stressors. We have previously found that high-altitude hypoxia induces disorders of the brain-endocrine-immune network through activation of CRF and CRFR1 in the brain and periphery that include activation of the HPA axis in a time- and dose-dependent manner, impaired or improved learning and memory, and anxiety-like behavioral change. Meanwhile, hypoxia induces dysfunctions of the hypothalamo-pituitary-endocrine and immune systems, including suppression of growth and development, as well as inhibition of reproductive, metabolic and immune functions. In contrast, the small mammals that live on the Qinghai-Tibet Plateau alpine meadow display low responsiveness to extreme high-altitude-hypoxia challenge, suggesting well-acclimatized genes and a physiological strategy that developed during evolution through interactions between the genes and environment. All the findings provide evidence for understanding the neuroendocrine mechanisms of hypoxia-induced physiological dysfunction. This review extends these findings.

  20. Hypoxia Inducible Factor (HIF transcription factor family expansion, diversification, divergence and selection in eukaryotes.

    Directory of Open Access Journals (Sweden)

    Allie M Graham

    Full Text Available Hypoxia inducible factor (HIF transcription factors are crucial for regulating a variety of cellular activities in response to oxygen stress (hypoxia. In this study, we determine the evolutionary history of HIF genes and their associated transactivation domains, as well as perform selection and functional divergence analyses across their four characteristic domains. Here we show that the HIF genes are restricted to metazoans: At least one HIF-α homolog is found within the genomes of non-bilaterians and bilaterian invertebrates, while most vertebrate genomes contain between two and six HIF-α genes. We also find widespread purifying selection across all four characteristic domain types, bHLH, PAS, NTAD, CTAD, in HIF-α genes, and evidence for Type I functional divergence between HIF-1α, HIF-2α /EPAS, and invertebrate HIF genes. Overall, we describe the evolutionary histories of the HIF transcription factor gene family and its associated transactivation domains in eukaryotes. We show that the NTAD and CTAD domains appear de novo, without any appearance outside of the HIF-α subunits. Although they both appear in invertebrates as well as vertebrate HIF- α sequences, there seems to have been a substantial loss across invertebrates or were convergently acquired in these few lineages. We reaffirm that HIF-1α is phylogenetically conserved among most metazoans, whereas HIF-2α appeared later. Overall, our findings can be attributed to the substantial integration of this transcription factor family into the critical tasks associated with maintenance of oxygen homeostasis and vascularization, particularly in the vertebrate lineage.

  1. Hypoxia induces miR-210, leading to anti-apoptosis in ovarian follicular cells of marine medaka Oryzias melastigma

    Energy Technology Data Exchange (ETDEWEB)

    Tse, Anna Chung-Kwan [School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR (China); State Key Laboratory in Marine Pollution, Hong Kong SAR (China); Li, Jing-Woei; Chan, Ting-Fung [School of Life Sciences, Hong Kong Bioinformatics Centre, The Chinese University of Hong Kong, Hong Kong SAR (China); Wu, Rudolf Shiu-Sun [School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR (China); State Key Laboratory in Marine Pollution, Hong Kong SAR (China); Lai, Keng-Po, E-mail: balllai@hku.hk [School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR (China); State Key Laboratory in Marine Pollution, Hong Kong SAR (China)

    2015-08-15

    Highlights: • We demonstrate hypoxia induced miR-210 in ovarian follicular cells. • We show anti-apoptotic roles of miR-210 in ovarian follicular cells under hypoxia. • Apoptotic genes (DLC1, SLK, TNFRSF10B, RBM25, and USP7) are target of miR-210. • MiR-210 is vital for ovarian follicular cells proliferation in response to hypoxia. - Abstract: Hypoxia is a major global problem that impairs reproductive functions and reduces the quality and quantity of gametes and the fertilization success of marine fish. Nevertheless, the detailed molecular mechanism underlying hypoxia-induced female reproductive impairment remains largely unknown. There is increasing evidence that miRNA is vital in regulating ovarian functions and is closely associated with female fertility in humans. Certain miRNAs that regulate apoptotic genes can be induced by hypoxia, resulting in cell apoptosis. Using primary ovarian follicular cells of the marine medaka, Oryzias melastigma, as a model, we investigated the response of miR-210 to hypoxic stress in ovarian tissues to see if it would interrupt reproductive functions. A significant induction of miR-210 was found in primary ovarian follicular cells exposed to hypoxia, and gene ontology analysis further highlighted the potential roles of miR-210 in cell proliferation, cell differentiation, and cell apoptosis. A number of miR-210 target apoptotic genes, including Deleted in liver cancer 1 protein (DLC1), STE20-like serine/threonine-protein kinase (SLK), tumor necrosis factor receptor superfamily member 10b (TNFRSF10B), RNA binding motif protein 25 (RBM25), and Ubiquitin-specific-processing protease 7 (USP7), were identified. We further showed that ectopic expression of miR-210 would result in down-regulation of these apoptotic genes. On the other hand, the inhibition of miR-210 promoted apoptotic cell death and the expression of apoptotic marker – caspase 3 in follicular cells under hypoxic treatment, supporting the regulatory role of mi

  2. Cancer drug troglitazone stimulates the growth and response of renal cells to hypoxia inducible factors

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    Taub, Mary, E-mail: biochtau@buffalo.edu

    2016-03-11

    Troglitazone has been used to suppress the growth of a number of tumors through apoptosis and autophagy. However, previous in vitro studies have employed very high concentrations of troglitazone (≥10{sup −5} M) in order to elicit growth inhibitory effects. In this report, when employing lower concentrations of troglitazone in defined medium, troglitazone was observed to stimulate the growth of primary renal proximal tubule (RPT) cells. Rosiglitazone, like troglitazone, is a thiazolidinedione (TZD) that is known to activate Peroxisome Proliferator Activated Receptor Υ (PPARΥ). Notably, rosiglitazone also stimulates RPT cell growth, as does Υ-linolenic acids, another PPARΥ agonist. The PPARΥ antagonist GW9662 inhibited the growth stimulatory effect of troglitazone. In addition, troglitazone stimulated transcription by a PPAR Response Element/Luciferase construct. These results are consistent with the involvement of PPARΥ as a mediator of the growth stimulatory effect of troglitazone. In a number of tumor cells, the expression of hypoxia inducible factor (HIF) is increased, promoting the expression of HIF inducible genes, and vascularization. Troglitazone was observed to stimulate transcription by a HIF/luciferase construct. These observations indicate that troglitazone not only promotes growth, also the survival of RPT cells under conditions of hypoxia. - Highlights: • Troglitazone and rosiglitazone stimulate renal proximal tubule cell growth. • Troglitazone and linolenic acid stimulate growth via PPARϒ. • Linolenic acid stimulates growth in the presence of fatty acid free serum albumin. • Rosiglitazone stimulates transcription by a HRE luciferase construct.

  3. Hypoxia inducible factor-1 alpha stabilization for regenerative therapy in traumatic brain injury

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    Mushfiquddin Khan

    2017-01-01

    Full Text Available Mild traumatic brain injury (TBI, also called concussion, initiates sequelae leading to motor deficits, cognitive impairments and subtly compromised neurobehaviors. While the acute phase of TBI is associated with neuroinflammation and nitroxidative burst, the chronic phase shows a lack of stimulation of the neurorepair process and regeneration. The deficiency of nitric oxide (NO, the consequent disturbed NO metabolome, and imbalanced mechanisms of S-nitrosylation are implicated in blocking the mechanisms of neurorepair processes and functional recovery in the both phases. Hypoxia inducible factor-1 alpha (HIF-1α, a master regulator of hypoxia/ischemia, stimulates the process of neurorepair and thus aids in functional recovery after brain trauma. The activity of HIF-1α is regulated by NO via the mechanism of S-nitrosylation of HIF-1α. S-nitrosylation is dynamically regulated by NO metabolites such as S-nitrosoglutathione (GSNO and peroxynitrite. GSNO stabilizes, and peroxynitrite destabilizes HIF-1α. Exogenously administered GSNO was found not only to stabilize HIF-1α and to induce HIF-1α-dependent genes but also to stimulate the regeneration process and to aid in functional recovery in TBI animals.

  4. Flavonoid Compound Icariin Activates Hypoxia Inducible Factor-1α in Chondrocytes and Promotes Articular Cartilage Repair.

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    Pengzhen Wang

    Full Text Available Articular cartilage has poor capability for repair following trauma or degenerative pathology due to avascular property, low cell density and migratory ability. Discovery of novel therapeutic approaches for articular cartilage repair remains a significant clinical need. Hypoxia is a hallmark for cartilage development and pathology. Hypoxia inducible factor-1alpha (HIF-1α has been identified as a key mediator for chondrocytes to response to fluctuations of oxygen availability during cartilage development or repair. This suggests that HIF-1α may serve as a target for modulating chondrocyte functions. In this study, using phenotypic cellular screen assays, we identify that Icariin, an active flavonoid component from Herba Epimedii, activates HIF-1α expression in chondrocytes. We performed systemic in vitro and in vivo analysis to determine the roles of Icariin in regulation of chondrogenesis. Our results show that Icariin significantly increases hypoxia responsive element luciferase reporter activity, which is accompanied by increased accumulation and nuclear translocation of HIF-1α in murine chondrocytes. The phenotype is associated with inhibiting PHD activity through interaction between Icariin and iron ions. The upregulation of HIF-1α mRNA levels in chondrocytes persists during chondrogenic differentiation for 7 and 14 days. Icariin (10-6 M increases the proliferation of chondrocytes or chondroprogenitors examined by MTT, BrdU incorporation or colony formation assays. Icariin enhances chondrogenic marker expression in a micromass culture including Sox9, collagen type 2 (Col2α1 and aggrecan as determined by real-time PCR and promotes extracellular matrix (ECM synthesis indicated by Alcian blue staining. ELISA assays show dramatically increased production of aggrecan and hydroxyproline in Icariin-treated cultures at day 14 of chondrogenic differentiation as compared with the controls. Meanwhile, the expression of chondrocyte catabolic

  5. Rapamycin attenuates hypoxia-induced pulmonary vascular remodeling and right ventricular hypertrophy in mice

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    Tillmanns Harald H

    2007-02-01

    Full Text Available Abstract Background Chronic hypoxia induces pulmonary arterial hypertension (PAH. Smooth muscle cell (SMC proliferation and hypertrophy are important contributors to the remodeling that occurs in chronic hypoxic pulmonary vasculature. We hypothesized that rapamycin (RAPA, a potent cell cycle inhibitor, prevents pulmonary hypertension in chronic hypoxic mice. Methods Mice were held either at normoxia (N; 21% O2 or at hypobaric hypoxia (H; 0.5 atm; ~10% O2. RAPA-treated animals (3 mg/kg*d, i.p. were compared to animals injected with vehicle alone. Proliferative activity within the pulmonary arteries was quantified by staining for Ki67 (positive nuclei/vessel and media area was quantified by computer-aided planimetry after immune-labeling for α-smooth muscle actin (pixel/vessel. The ratio of right ventricle to left ventricle plus septum (RV/[LV+S] was used to determine right ventricular hypertrophy. Results Proliferative activity increased by 34% at day 4 in mice held under H (median: 0.38 compared to N (median: 0.28, p = 0.028 which was completely blocked by RAPA (median HO+RAPA: 0.23, p = 0.003. H-induced proliferation had leveled off within 3 weeks. At this time point media area had, however, increased by 53% from 91 (N to 139 (H, p Conclusion Therapy with rapamycin may represent a new strategy for the treatment of pulmonary hypertension.

  6. NOX2 Antisense Attenuates Hypoxia-Induced Oxidative Stress and Apoptosis in Cardiomyocyte.

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    Yu, Bo; Meng, Fanbo; Yang, Yushuang; Liu, Dongna; Shi, Kaiyao

    2016-01-01

    Heart ischemia is a hypoxia related disease. NOX2 and HIF-1α proteins were increased in cardiomyocytes after acute myocardial infarction. However, the relationship of the hypoxia-induced HIF-1α. NOX2-derived oxidative stress and apoptosis in cardiomyocyte remains unclear. In the current study, we use NOX2 antisense strategy to investigate the role of NOX2 in hypoxia-induced oxidative stress and apoptosis in rat cardiomyocytes. Here, we show that transduction of ADV-NOX2-AS induces potent silencing of NOX2 in cardiomyocytes, and resulting in attenuation of hypoxia-induced oxidative stress and apoptosis. This study indicates the potential of antisense-based therapies and validates NOX2 as a potent therapeutic candidate for heart ischemia.

  7. Homodimerization of the PAS-B domains of hypoxia-inducible factors.

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    Zhu, Jing; Martinez-Yamout, Maria; Cardoso, Rosa; Yan, Jiangli; Love, Robert A; Grodsky, Neil; Brooun, Alexei; Dyson, H Jane

    2012-06-14

    The Per-Arnt-Sim (PAS) domains of hypoxia-inducible transcription factors (HIF) mediate heterodimer formation between the HIF-α forms that are induced in the event of cellular hypoxia and the constitutive HIF-β variants. Previous efforts toward structural characterization of the HIF-1α PAS domains were limited by protein stability. Using homology modeling based on the published crystal structure of the PAS-B domain of the homologous protein HIF-2α in complex with the partner HIF-β (also known as ARNT), we have identified a variant of HIF-1α with improved solubility, monodispersity, and stability. Purified solutions of the PAS-B domains of HIF-1α and HIF-2α differ in their propensity for homodimer formation. In an attempt to understand the structural basis for this difference, and to document the structural changes that accompany homodimer formation, we have undertaken a comparative NMR study of the PAS-B domains of HIF-1α and HIF-2α and mutants of HIF-1α that mimic the behavior of HIF-2α. The NMR spectra of all of these domains are very similar, consistent with the similarity of their amino acid sequences. However, the greater propensity of the HIF-1α PAS-B domain to form dimers as the concentration was increased allowed us to determine the site of homodimerization and pointed toward possible sequence changes in HIF-1α that might discourage the formation of homodimers.

  8. [Salidroside inhibits hypoxia-induced phenotypic modulation of corpus cavernosum smooth muscle cells in vitro].

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    Chen, Gang; Huang, Xiao-Jun; Lü, Bo-Dong; Chen, Shi-Tao; Zhang, Shi-Geng; Yang, Ke-Bing

    2013-08-01

    To explore the effects of salidroside on the phenotypic modulation of corpus cavernosum smooth muscle cells (CCSMC) in hypoxic SD rats. CCSMCs were cultured in vitro and identified by immunohistochemistry. The cells were divided into six groups: normal control (21% O2), hypoxia (1% O2), hypoxia + salidroside 1 mg/L, hypoxia + salidroside 3 mg/L, hypoxia + salidroside 5 mg/L and hypoxia + PGE1 0.4 microg/L, and then cultured for 48 hours. The relative expressions of alpha-actin and osteopontin (OPN) in each group were determined by RT-PCR. The in vitro cultured CCSMCs grew well, with anti-alpha-smooth muscle actin monoclonal antibodies immunohistochemically positive. The relative expression of alpha-actin was markedly decreased while that of OPN remarkably increased in the hypoxia group as compared with the normal control group (P salidroside 5 mg/L group showed a significantly higher expression of alpha-actin and lower expression of OPN than the hypoxia group (P 0.05). Hypoxia can reduce the relative expression level of alpha-actin and increase that of OPN in the CCSMCs of SD rats, namely, induce their phenotypic modulation from the contraction to the non-contraction type. Salidroside can restrain hypoxia-induced phenotypic modulation of CCSMCs, and its inhibitory effect at 5 mg/L is similar to that of PGE1.

  9. COGNATE: comparative gene annotation characterizer.

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    Wilbrandt, Jeanne; Misof, Bernhard; Niehuis, Oliver

    2017-07-17

    The comparison of gene and genome structures across species has the potential to reveal major trends of genome evolution. However, such a comparative approach is currently hampered by a lack of standardization (e.g., Elliott TA, Gregory TR, Philos Trans Royal Soc B: Biol Sci 370:20140331, 2015). For example, testing the hypothesis that the total amount of coding sequences is a reliable measure of potential proteome diversity (Wang M, Kurland CG, Caetano-Anollés G, PNAS 108:11954, 2011) requires the application of standardized definitions of coding sequence and genes to create both comparable and comprehensive data sets and corresponding summary statistics. However, such standard definitions either do not exist or are not consistently applied. These circumstances call for a standard at the descriptive level using a minimum of parameters as well as an undeviating use of standardized terms, and for software that infers the required data under these strict definitions. The acquisition of a comprehensive, descriptive, and standardized set of parameters and summary statistics for genome publications and further analyses can thus greatly benefit from the availability of an easy to use standard tool. We developed a new open-source command-line tool, COGNATE (Comparative Gene Annotation Characterizer), which uses a given genome assembly and its annotation of protein-coding genes for a detailed description of the respective gene and genome structure parameters. Additionally, we revised the standard definitions of gene and genome structures and provide the definitions used by COGNATE as a working draft suggestion for further reference. Complete parameter lists and summary statistics are inferred using this set of definitions to allow down-stream analyses and to provide an overview of the genome and gene repertoire characteristics. COGNATE is written in Perl and freely available at the ZFMK homepage ( https://www.zfmk.de/en/COGNATE ) and on github ( https

  10. Red blood cell storage increases hypoxia-induced nitric oxide bioavailability and methemoglobin formation in vitro and in vivo

    NARCIS (Netherlands)

    Almac, Emre; Bezemer, Rick; Hilarius-Stokman, Petra M.; Goedhart, Peter; de Korte, Dirk; Verhoeven, Arthur J.; Ince, Can

    2014-01-01

    In this study we investigated whether storage of red blood cells (RBCs) leads to alterations in nitrite reductase activity, hence in altered hypoxia-induced nitric oxide (NO) bioavailability and methemoglobin formation. Hypoxia-induced NO bioavailability and methemoglobin formation were measured in

  11. Comparative and Experimental Studies on the Genes Altered by Chronic Hypoxia in Human Brain Microendothelial Cells

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    Eugenia Mata-Greenwood

    2017-05-01

    Full Text Available Background : Hypoxia inducible factor 1 alpha (HIF1A is a master regulator of acute hypoxia; however, with chronic hypoxia, HIF1A levels return to the normoxic levels. Importantly, the genes that are involved in the cell survival and viability under chronic hypoxia are not known. Therefore, we tested the hypothesis that chronic hypoxia leads to the upregulation of a core group of genes with associated changes in the promoter DNA methylation that mediates the cell survival under hypoxia.Results : We examined the effect of chronic hypoxia (3 days; 0.5% oxygen on human brain micro endothelial cells (HBMEC viability and apoptosis. Hypoxia caused a significant reduction in cell viability and an increase in apoptosis. Next, we examined chronic hypoxia associated changes in transcriptome and genome-wide promoter methylation. The data obtained was compared with 16 other microarray studies on chronic hypoxia. Nine genes were altered in response to chronic hypoxia in all 17 studies. Interestingly, HIF1A was not altered with chronic hypoxia in any of the studies. Furthermore, we compared our data to three other studies that identified HIF-responsive genes by various approaches. Only two genes were found to be HIF dependent. We silenced each of these 9 genes using CRISPR/Cas9 system. Downregulation of EGLN3 significantly increased the cell death under chronic hypoxia, whereas downregulation of ERO1L, ENO2, adrenomedullin, and spag4 reduced the cell death under hypoxia.Conclusions : We provide a core group of genes that regulates cellular acclimatization under chronic hypoxic stress, and most of them are HIF independent.

  12. Inhibition of hypoxia inducible factor 1 and topoisomerase with acriflavine sensitizes perihilar cholangiocarcinomas to photodynamic therapy

    NARCIS (Netherlands)

    Weijer, R.; Broekgaarden, M.; Krekorian, M.; Alles, L.K.; van Wijk, A.C; Mackaaij, C.; Verheij, J.; van der Wal, A.C.; van Gullik, T.M.; Storm, Gerrit; Heger, M.

    2016-01-01

    Background: Photodynamic therapy (PDT) induces tumor cell death by oxidative stress and hypoxia but also survival signaling through activation of hypoxia-inducible factor 1 (HIF-1). Since perihilar cholangiocarcinomas are relatively recalcitrant to PDT, the aims were to (1) determine the expression

  13. Inhibition of hypoxia inducible factor 1 and topoisomerase with acriflavine sensitizes perihilar cholangiocarcinomas to photodynamic therapy

    NARCIS (Netherlands)

    Weijer, Ruud; Broekgaarden, Mans; Krekorian, Massis; Alles, Lindy K.; van Wijk, Albert C.; Mackaaij, Claire; Verheij, Joanne; van der Wal, Allard C.; van Gulik, Thomas M.; Storm, Gert; Heger, Michal

    2016-01-01

    Photodynamic therapy (PDT) induces tumor cell death by oxidative stress and hypoxia but also survival signaling through activation of hypoxia-inducible factor 1 (HIF-1). Since perihilar cholangiocarcinomas are relatively recalcitrant to PDT, the aims were to (1) determine the expression levels of

  14. Reducible poly(amido ethylenediamine) for hypoxia-inducible VEGF delivery

    NARCIS (Netherlands)

    Christensen, Lane V.; Christensen, L.; Chang, Chien-Wen; Yockman, James W.; Conners, Rafe; Jackson, Heidi; Zhong, Zhiyuan; Feijen, Jan; Bull, David A.; Kim, Sung Wan

    2007-01-01

    Delivery of the hypoxia-inducible vascular endothelial growth factor (RTP-VEGF) plasmid using a novel reducible disulfide poly(amido ethylenediamine) (SS-PAED) polymer carrier was studied in vitro and in vivo. In vitro transfection of primary rat cardiomyoblasts (H9C2) showed SS-PAED at a weighted

  15. Hypoxia-inducible factor-1α regulates β cell function in mouse and human islets

    Science.gov (United States)

    Cheng, Kim; Ho, Kenneth; Stokes, Rebecca; Scott, Christopher; Lau, Sue Mei; Hawthorne, Wayne J.; O’Connell, Philip J.; Loudovaris, Thomas; Kay, Thomas W.; Kulkarni, Rohit N.; Okada, Terumasa; Wang, Xiaohui L.; Yim, Sun Hee; Shah, Yatrik; Grey, Shane T.; Biankin, Andrew V.; Kench, James G.; Laybutt, D. Ross; Gonzalez, Frank J.; Kahn, C. Ronald; Gunton, Jenny E.

    2010-01-01

    Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that regulates cellular stress responses. While the levels of HIF-1α protein are tightly regulated, recent studies suggest that it can be active under normoxic conditions. We hypothesized that HIF-1α is required for normal β cell function and reserve and that dysregulation may contribute to the pathogenesis of type 2 diabetes (T2D). Here we show that HIF-1α protein is present at low levels in mouse and human normoxic β cells and islets. Decreased levels of HIF-1α impaired glucose-stimulated ATP generation and β cell function. C57BL/6 mice with β cell–specific Hif1a disruption (referred to herein as β-Hif1a-null mice) exhibited glucose intolerance, β cell dysfunction, and developed severe glucose intolerance on a high-fat diet. Increasing HIF-1α levels by inhibiting its degradation through iron chelation markedly improved insulin secretion and glucose tolerance in control mice fed a high-fat diet but not in β-Hif1a-null mice. Increasing HIF-1α levels markedly increased expression of ARNT and other genes in human T2D islets and improved their function. Further analysis indicated that HIF-1α was bound to the Arnt promoter in a mouse β cell line, suggesting direct regulation. Taken together, these findings suggest an important role for HIF-1α in β cell reserve and regulation of ARNT expression and demonstrate that HIF-1α is a potential therapeutic target for the β cell dysfunction of T2D. PMID:20440072

  16. Notch signaling modulates hypoxia-induced neuroendocrine differentiation of human prostate cancer cells.

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    Danza, Giovanna; Di Serio, Claudia; Rosati, Fabiana; Lonetto, Giuseppe; Sturli, Niccolò; Kacer, Doreen; Pennella, Antonio; Ventimiglia, Giuseppina; Barucci, Riccardo; Piscazzi, Annamaria; Prudovsky, Igor; Landriscina, Matteo; Marchionni, Niccolò; Tarantini, Francesca

    2012-02-01

    Prostate carcinoma is among the most common causes of cancer-related death in men, representing 15% of all male malignancies in developed countries. Neuroendocrine differentiation (NED) has been associated with tumor progression, poor prognosis, and with the androgen-independent status. Currently, no successful therapy exists for advanced, castration-resistant disease. Because hypoxia has been linked to prostate cancer progression and unfavorable outcome, we sought to determine whether hypoxia would impact the degree of neuroendocrine differentiation of prostate cancer cells in vitro. Exposure of LNCaP cells to low oxygen tension induced a neuroendocrine phenotype, associated with an increased expression of the transcription factor neurogenin3 and neuroendocrine markers, such as neuron-specific enolase, chromogranin A, and β3-tubulin. Moreover, hypoxia triggered a significant decrease of Notch 1 and Notch 2 mRNA and protein expression, with subsequent downregulation of Notch-mediated signaling, as shown by reduced levels of the Notch target genes, Hes1 and Hey1. NED was promoted by attenuation of Hes1 transcription, as cells expressing a dominant-negative form of Hes1 displayed increased levels of neuroendocrine markers under normoxic conditions. Although hypoxia downregulated Notch 1 and Notch 2 mRNA transcription and receptor activation also in the androgen-independent cell lines, PC-3 and Du145, it did not change the extent of NED in these cultures, suggesting that androgen sensitivity may be required for transdifferentiation to occur. Hypoxia induces NED of LNCaP cells in vitro, which seems to be driven by the inhibition of Notch signaling with subsequent downregulation of Hes1 transcription. ©2011 AACR.

  17. Chronic intermittent hypoxia induces cardiac inflammation and dysfunction in a rat obstructive sleep apnea model.

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    Wei, Qin; Bian, Yeping; Yu, Fuchao; Zhang, Qiang; Zhang, Guanghao; Li, Yang; Song, Songsong; Ren, Xiaomei; Tong, Jiayi

    2016-11-01

    Chronic intermittent hypoxia is considered to play an important role in cardiovascular pathogenesis during the development of obstructive sleep apnea (OSA). We used a well-described OSA rat model induced with simultaneous intermittent hypoxia. Male Sprague Dawley rats were individually placed into plexiglass chambers with air pressure and components were electronically controlled. The rats were exposed to intermittent hypoxia 8 hours daily for 5 weeks. The changes of cardiac structure and function were examined by ultrasound. The cardiac pathology, apoptosis, and fibrosis were analyzed by H&E staining, TUNNEL assay, and picosirius staining, respectively. The expression of inflammation and fibrosis marker genes was analyzed by quantitative real-time PCR and Western blot. Chronic intermittent hypoxia/low pressure resulted in significant increase of left ventricular internal diameters (LVIDs), end-systolic volume (ESV), end-diastolic volume (EDV), and blood lactate level and marked reduction in ejection fraction and fractional shortening. Chronic intermittent hypoxia increased TUNNEL-positive myocytes, disrupted normal arrangement of cardiac fibers, and increased Sirius stained collagen fibers. The expression levels of hypoxia induced factor (HIF)-1α, NF-kB, IL-6, and matrix metallopeptidase 2 (MMP-2) were significantly increased in the heart of rats exposed to chronic intermittent hypoxia. In conclusion, the left ventricular function was adversely affected by chronic intermittent hypoxia, which is associated with increased expression of HIF-1α and NF-kB signaling molecules and development of cardiac inflammation, apoptosis and fibrosis. © 2016 by the Journal of Biomedical Research. All rights reserved.

  18. mRNA cycles through hypoxia-induced stress granules in live Drosophila embryonic muscles.

    Science.gov (United States)

    van der Laan, Annelies M A; van Gemert, Alice M C; Dirks, Roeland W; Noordermeer, Jasprina N; Fradkin, Lee G; Tanke, Hans J; Jost, Carolina R

    2012-01-01

    In some myopathies, hypoxia can be the result of pathologic effects like muscle necrosis and abnormal blood flow. At the molecular level, the consequence of hypoxic conditions is not yet fully understood. Under stress conditions, many housekeeping gene mRNAs are translationally silenced, while translation of other mRNAs increases. Alterations to the pool of mRNAs available for translation lead to the formation of so-called stress granules containing both mRNAs and proteins. Stress granule formation and dynamics have been investigated using cells in culture, but have not yet been examined in vivo. In Drosophila embryonic muscles, we found that hypoxia induces the formation of sarcoplasmic granules containing the established stress granule markers RIN and dFMR1. Upon restoration of normoxia, the observed granules were decreased in size, indicating that their formation might be reversible. Employing photobleaching approaches, we found that a cytoplasmic reporter mRNA rapidly shuttles in and out of the granules. Hence, stress granules are highly dynamic complexes and not simple temporary storage sites. Although mRNA rapidly cycles through the granules, its movement throughout the muscle is, remarkably, spatially restricted by the presence of yet undefined myofiber domains. Our results suggest that in hypoxic muscles mRNA remains highly mobile; however, its movement throughout the muscle is restricted by certain boundaries. The development of this Drosophila hypoxia model makes it possible to study the formation and dynamics of stress granules and their associated mRNAs and proteins in a living organism.

  19. NOTCH SIGNALLING MODULATES HYPOXIA-INDUCED NEUROENDOCRINE DIFFERENTIATION OF HUMAN PROSTATE CANCER CELLS

    Science.gov (United States)

    Danza, Giovanna; Di Serio, Claudia; Rosati, Fabiana; Lonetto, Giuseppe; Sturli, Niccolò; Kacer, Doreen; Pennella, Antonio; Ventimiglia, Giuseppina; Barucci, Riccardo; Piscazzi, Annamaria; Prudovsky, Igor; Landriscina, Matteo; Marchionni, Niccolò; Tarantini, Francesca

    2012-01-01

    Prostate carcinoma is among the most common causes of cancer-related death in men, representing 15% of all male malignancies in developed countries. Neuroendocrine differentiation has been associated with tumor progression, poor prognosis and with the androgen-independent status. Currently, no successful therapy exists for advanced, castration-resistant disease. Because hypoxia has been linked to prostate cancer progression and unfavourable outcome, we sought to determine whether hypoxia would impact the degree of neuroendocrine differentiation of prostate cancer cells, in vitro. Results exposure of LNCaP cells to low oxygen tension induced a neuroendocrine phenotype, associated with an increased expression of the transcription factor neurogenin3 and neuroendocrine markers, such as neuron-specific enolase, chromogranin A and β3-tubulin. Moreover, hypoxia triggered a significant decrease of Notch 1 and Notch 2 mRNA and protein expression, with subsequent down regulation of Notch-mediated signalling, as demonstrated by reduced levels of the Notch target genes, Hes1 and Hey1. Neuroendocrine differentiation was promoted by attenuation of Hes1 transcription, as cells expressing a dominant negative form of Hes1 displayed increased levels of neuroendocrine markers under normoxic conditions. Although hypoxia down regulated Notch 1 and Notch 2 mRNA transcription and receptor activation also in the androgen independent cell lines, PC3 and Du145, it did not change the extent of NE differentiation in these cultures, suggesting that androgen sensitivity may be required for transdifferentiation to occur. Conclusions hypoxia induces neuroendocrine differentiation of LNCaP cells in vitro, which appears to be driven by the inhibition of Notch signalling with subsequent down-regulation of Hes1 transcription. PMID:22172337

  20. Hypoxia-induced cytotoxic drug resistance in osteosarcoma is independent of HIF-1Alpha.

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    Jennifer Adamski

    Full Text Available Survival rates from childhood cancer have improved dramatically in the last 40 years, such that over 80% of children are now cured. However in certain subgroups, including metastatic osteosarcoma, survival has remained stubbornly poor, despite dose intensive multi-agent chemotherapy regimens, and new therapeutic approaches are needed. Hypoxia is common in adult solid tumours and is associated with treatment resistance and poorer outcome. Hypoxia induces chemotherapy resistance in paediatric tumours including neuroblastoma, rhabdomyosarcoma and Ewing's sarcoma, in vitro, and this drug resistance is dependent on the oxygen-regulated transcription factor hypoxia inducible factor-1 (HIF-1. In this study the effects of hypoxia on the response of the osteosarcoma cell lines 791T, HOS and U2OS to the clinically relevant cytotoxics cisplatin, doxorubicin and etoposide were evaluated. Significant hypoxia-induced resistance to all three agents was seen in all three cell lines and hypoxia significantly reduced drug-induced apoptosis. Hypoxia also attenuated drug-induced activation of p53 in the p53 wild-type U2OS osteosarcoma cells. Drug resistance was not induced by HIF-1α stabilisation in normoxia by cobalt chloride nor reversed by the suppression of HIF-1α in hypoxia by shRNAi, siRNA, dominant negative HIF or inhibition with the small molecule NSC-134754, strongly suggesting that hypoxia-induced drug resistance in osteosarcoma cells is independent of HIF-1α. Inhibition of the phosphoinositide 3-kinase (PI3K pathway using the inhibitor PI-103 did not reverse hypoxia-induced drug resistance, suggesting the hypoxic activation of Akt in osteosarcoma cells does not play a significant role in hypoxia-induced drug resistance. Targeting hypoxia is an exciting prospect to improve current anti-cancer therapy and combat drug resistance. Significant hypoxia-induced drug resistance in osteosarcoma cells highlights the potential importance of hypoxia as a target

  1. ATR controls cellular adaptation to hypoxia through positive regulation of hypoxia-inducible factor 1 (HIF-1) expression.

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    Fallone, F; Britton, S; Nieto, L; Salles, B; Muller, C

    2013-09-12

    Tumor cells adaptation to severe oxygen deprivation (hypoxia) plays a major role in tumor progression. The transcription factor HIF-1 (hypoxia-inducible factor 1), whose α-subunit is stabilized under hypoxic conditions is a key component of this process. Recent studies showed that two members of the phosphoinositide 3-kinase-related kinases (PIKKs) family, ATM (ataxia telangiectasia mutated) and DNA-PK (DNA-dependent protein kinase), regulate the hypoxic-dependent accumulation of HIF-1. These proteins initiate cellular stress responses when DNA damage occurs. In addition, it has been demonstrated that extreme hypoxia induces a replicative stress resulting in regions of single-stranded DNA at stalled replication forks and the activation of ATR (ataxia telangiectasia and Rad3 related protein), another member of the PIKKs family. Here, we show that even less severe hypoxia (0.1% O2) also induces activation of ATR through replicative stress. Importantly, in using either transiently silenced ATR cells, cells expressing an inactive form of ATR or cells exposed to an ATR inhibitor (CGK733), we demonstrate that hypoxic ATR activation positively regulates the key transcription factor HIF-1 independently of the checkpoint kinase Chk1. We show that ATR kinase activity regulates HIF-1α at the translational level and we find that the elements necessary for the regulation of HIF-1α translation are located within the coding region of HIF-1α mRNA. Finally, by using three independent cellular models, we clearly show that the loss of ATR expression and/or kinase activity results in the decrease of HIF-1 DNA binding under hypoxia and consequently affects protein expression levels of two HIF-1 target genes, GLUT-1 and CAIX. Taken together, our data show a new function for ATR in cellular adaptation to hypoxia through regulation of HIF-1α translation. Our work offers new prospect for cancer therapy using ATR inhibitors with the potential to decrease cellular adaptation in hypoxic

  2. Overexpression of Hypoxia-Inducible Factor-1α Exacerbates Endothelial Barrier Dysfunction Induced by Hypoxia

    Directory of Open Access Journals (Sweden)

    Pei Wang

    2013-09-01

    Full Text Available Background/Aims: The mechanisms involved in endothelial barrier dysfunction induced by hypoxia are incompletely understood. There is debate about the role of hypoxia-inducible factor-1α (HIF-1α in endothelial barrier disruption. The aim of this study was to investigate the effect of genetic overexpression of HIF-1α on barrier function and the underlying mechanisms in hypoxic endothelial cells. Methods: The plasmid pcDNA3.1/V5-His-HIF-1α was stably transfected into human endothelial cells. The cells were exposed to normoxia or hypoxia. The mRNA and protein expressions of HIF-1α were detected by RT-PCR and Western blot respectively. The barrier function was assessed by measuring the transendothelial electrical resistance (TER. The Western blot analysis was used to determine the protein expression of glucose transporter-1 (GLUT-1, zonular occludens-1 (ZO-1, occludin, and myosin light chain kinase (MLCK in endothelial cells. The mRNA expression of proinflammatory cytokines was detected by qRT-PCR. Results: Genetic overexpression of HIF-1α significantly increased the mRNA and protein expression of HIF-1α in endothelial cells. The overexpression of HIF-1α enhanced the hypoxia-induced increase of HIF-1α and GLUT-1 protein expression. HIF-1α overexpression not only exacerbated hypoxia-induced endothelial barrier dysfunction but also augmented hypoxia-induced up-regulation of MLCK protein expression. HIF-1α overexpression also enhanced IL-1β, IL-6 and TNF-α mRNA expression. Conclusion: We provide evidence that genetic overexpression of HIF-1α aggravates the hypoxia-induced endothelial barrier dysfunction via enhancing the up-regulation of MLCK protein expression caused by hypoxia, suggesting a potential role for HIF-1α in the pathogenesis of endothelial barrier dysfunction in hypoxia.

  3. Hypoxia inducible factor 3α plays a critical role in alveolarization and distal epithelial cell differentiation during mouse lung development.

    Directory of Open Access Journals (Sweden)

    Yadi Huang

    Full Text Available Lung development occurs under relative hypoxia and the most important oxygen-sensitive response pathway is driven by Hypoxia Inducible Factors (HIF. HIFs are heterodimeric transcription factors of an oxygen-sensitive subunit, HIFα, and a constitutively expressed subunit, HIF1β. HIF1α and HIF2α, encoded by two separate genes, contribute to the activation of hypoxia inducible genes. A third HIFα gene, HIF3α, is subject to alternative promoter usage and splicing, leading to three major isoforms, HIF3α, NEPAS and IPAS. HIF3α gene products add to the complexity of the hypoxia response as they function as dominant negative inhibitors (IPAS or weak transcriptional activators (HIF3α/NEPAS. Previously, we and others have shown the importance of the Hif1α and Hif2α factors in lung development, and here we investigated the role of Hif3α during pulmonary development. Therefore, HIF3α was conditionally expressed in airway epithelial cells during gestation and although HIF3α transgenic mice were born alive and appeared normal, their lungs showed clear abnormalities, including a post-pseudoglandular branching defect and a decreased number of alveoli. The HIF3α expressing lungs displayed reduced numbers of Clara cells, alveolar epithelial type I and type II cells. As a result of HIF3α expression, the level of Hif2α was reduced, but that of Hif1α was not affected. Two regulatory genes, Rarβ, involved in alveologenesis, and Foxp2, a transcriptional repressor of the Clara cell specific Ccsp gene, were significantly upregulated in the HIF3α expressing lungs. In addition, aberrant basal cells were observed distally as determined by the expression of Sox2 and p63. We show that Hif3α binds a conserved HRE site in the Sox2 promoter and weakly transactivated a reporter construct containing the Sox2 promoter region. Moreover, Hif3α affected the expression of genes not typically involved in the hypoxia response, providing evidence for a novel

  4. Impact of interleukin-6 on hypoxia-induced pulmonary hypertension and lung inflammation in mice

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    Izziki Mohamed

    2009-01-01

    Full Text Available Abstract Background Inflammation may contribute to the pathogenesis of various forms of pulmonary hypertension (PH. Recent studies in patients with idiopathic PH or PH associated with underlying diseases suggest a role for interleukin-6 (IL-6. Methods To determine whether endogenous IL-6 contributes to mediate hypoxic PH and lung inflammation, we studied IL-6-deficient (IL-6-/- and wild-type (IL-6+/+ mice exposed to hypoxia for 2 weeks. Results Right ventricular systolic pressure, right ventricle hypertrophy, and the number and media thickness of muscular pulmonary vessels were decreased in IL-6-/- mice compared to wild-type controls after 2 weeks' hypoxia, although the pressure response to acute hypoxia was similar in IL-6+/+ and IL-6-/- mice. Hypoxia exposure of IL-6+/+ mice led to marked increases in IL-6 mRNA and protein levels within the first week, with positive IL-6 immunostaining in the pulmonary vessel walls. Lung IL-6 receptor and gp 130 (the IL-6 signal transducer mRNA levels increased after 1 and 2 weeks' hypoxia. In vitro studies of cultured human pulmonary-artery smooth-muscle-cells (PA-SMCs and microvascular endothelial cells revealed prominent synthesis of IL-6 by PA-SMCs, with further stimulation by hypoxia. IL-6 also markedly stimulated PA-SMC migration without affecting proliferation. Hypoxic IL-6-/- mice showed less inflammatory cell recruitment in the lungs, compared to hypoxic wild-type mice, as assessed by lung protein levels and immunostaining for the specific macrophage marker F4/80, with no difference in lung expression of adhesion molecules or cytokines. Conclusion These data suggest that IL-6 may be actively involved in hypoxia-induced lung inflammation and pulmonary vascular remodeling in mice.

  5. MiR-142 modulates human pancreatic cancer proliferation and invasion by targeting hypoxia-inducible factor 1 (HIF-1α in the tumor microenvironments

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    Yebin Lu

    2017-02-01

    Full Text Available MicroRNAs regulate most protein-coding genes, including genes important in cancer and other diseases. In this study, we demonstrated that the expression of miR-142 could be significantly suppressed in pancreatic cancer specimens and cell lines compared to their adjacent tissues and normal pancreatic cells. Growth and invasion of PANC-1 and SW1990 cells were attenuated by overexpression of miR-142 in vitro. With the help of bioinformatics analysis, hypoxia-inducible factor 1 (HIF-1α was identified to be a direct target of miR-142, and a luciferase reporter experiment confirmed this discovery. Overexpression of miR-142 decreases protein expression of HIF-1α. In the hypoxic microenvironment, HIF-1α was up-regulated while miR-142 was down-regulated. The invaded cells significantly increased in the hypoxic microenvironment compared to the normoxic microenvironment. The hypoxia treatment induced cells’ proliferation, and invasion could be inhibited by miR-142 overexpression or HIF-1α inhibition. Moreover, expression of epithelial-mesenchymal transition (EMT markers, Vimentin, VEGF-C and E-cad, was altered under hypoxia conditions and regulated by miR-142/HIF-1α. Above all, these findings provided insights on the functional mechanism of miR-142, suggesting that the miR-142/HIF-1α axis may interfere with the proliferative and invasive properties of pancreatic cancer cells, and indicated that miR-142 could be a potential therapeutic target for pancreatic cancer.

  6. Hypoxia-induced HIF1α targets in melanocytes reveal a molecular profile associated with poor melanoma prognosis.

    Science.gov (United States)

    Loftus, Stacie K; Baxter, Laura L; Cronin, Julia C; Fufa, Temesgen D; Pavan, William J

    2017-05-01

    Hypoxia and HIF1α signaling direct tissue-specific gene responses regulating tumor progression, invasion, and metastasis. By integrating HIF1α knockdown and hypoxia-induced gene expression changes, this study identifies a melanocyte-specific, HIF1α-dependent/hypoxia-responsive gene expression signature. Integration of these gene expression changes with HIF1α ChIP-Seq analysis identifies 81 HIF1α direct target genes in melanocytes. The expression levels for 10 of the HIF1α direct targets - GAPDH, PKM, PPAT, DARS, DTWD1, SEH1L, ZNF292, RLF, AGTRAP, and GPC6 - are significantly correlated with reduced time of disease-free status in melanoma by logistic regression (P-value = 0.0013) and ROC curve analysis (AUC = 0.826, P-value < 0.0001). This HIF1α-regulated profile defines a melanocyte-specific response under hypoxia, and demonstrates the role of HIF1α as an invasive cell state gatekeeper in regulating cellular metabolism, chromatin and transcriptional regulation, vascularization, and invasion. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  7. Severe hypoxia induces chemo-resistance in clinical cervical tumors through MVP over-expression

    Directory of Open Access Journals (Sweden)

    Apolinario Rosa M

    2009-08-01

    Full Text Available Abstract Oxygen molecule modulates tumour response to radiotherapy. Higher radiation doses are required under hypoxic conditions to induce cell death. Hypoxia may inhibit the non-homologous end-joining DNA repair through down regulating Ku70/80 expression. Hypoxia induces drug resistance in clinical tumours, although the mechanism is not clearly elucidated. Vaults are ribonucleoprotein particles with a hollow barrel-like structure composed of three proteins: major vault protein (MVP, vault poly(ADP-ribose polymerase, and telomerase associated protein-1 and small untranslated RNA. Over-expression of MVP has been associated with chemotherapy resistance. Also, it has been related to poor outcome in patients treated with radiotherapy alone. The aim of the present study was to assess the relation of Major Vault Protein expression and tumor hypoxia in clinical cervical tumors. MVP, p53 and angiogenesis, together with tumor oxygenation, were determined in forty-three consecutive patients suffering from localized cervix carcinoma. High MVP expression was related to severe hypoxia compared to low MVP expressing tumors (p = 0.022. Tumors over-expressing MVP also showed increased angiogenesis (p = 0.003. Besides it, in this study we show for the first time that severe tumor hypoxia is associated with high MVP expression in clinical cervical tumors. Up-regulation of MVP by hypoxia is of critical relevance as chemotherapy is currently a standard treatment for those patients. From our results it could be suggested that hypoxia not only induces increased genetic instability, oncogenic properties and metastatization, but through the correlation observed with MVP expression, another pathway of chemo and radiation resistance could be developed.

  8. Targeted activation of endothelin-1 exacerbates hypoxia-induced pulmonary hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Satwiko, Muhammad Gahan [Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Ikeda, Koji [Department of Clinical Pharmacy, Kobe Pharmaceutical University, Kobe (Japan); Nakayama, Kazuhiko [Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Yagi, Keiko [Department of Clinical Pharmacy, Kobe Pharmaceutical University, Kobe (Japan); Hocher, Berthold [Institute for Nutritional Science, University of Potsdam, Potsdam (Germany); Hirata, Ken-ichi [Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Emoto, Noriaki, E-mail: emoto@med.kobe-u.ac.jp [Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Department of Clinical Pharmacy, Kobe Pharmaceutical University, Kobe (Japan)

    2015-09-25

    Pulmonary arterial hypertension (PAH) is a fatal disease that eventually results in right heart failure and death. Current pharmacologic therapies for PAH are limited, and there are no drugs that could completely cure PAH. Enhanced activity of endothelin system has been implicated in PAH severity and endothelin receptor antagonists have been used clinically to treat PAH. However, there is limited experimental evidence on the direct role of enhanced endothelin system activity in PAH. Here, we investigated the correlation between endothelin-1 (ET-1) and PAH using ET-1 transgenic (ETTG) mice. Exposure to chronic hypoxia increased right ventricular pressure and pulmonary arterial wall thickness in ETTG mice compared to those in wild type mice. Of note, ETTG mice exhibited modest but significant increase in right ventricular pressure and vessel wall thickness relative to wild type mice even under normoxic conditions. To induce severe PAH, we administered SU5416, a vascular endothelial growth factor receptor inhibitor, combined with exposure to chronic hypoxia. Treatment with SU5416 modestly aggravated hypoxia-induced pulmonary hypertension, right ventricular hypertrophy, and pulmonary arterial vessel wall thickening in ETTG mice in association with increased interleukin-6 expression in blood vessels. However, there was no sign of obliterative endothelial cell proliferation and plexiform lesion formation in the lungs. These results demonstrated that enhanced endothelin system activity could be a causative factor in the development of PAH and provided rationale for the inhibition of endothelin system to treat PAH. - Highlights: • Role of endothelin-1 in pulmonary arterial hypertension (PAH) was investigated. • The endothelin-1 transgenic (ETTG) and wild type (WT) mice were analyzed. • ETTG mice spontaneously developed PAH under normoxia conditions. • SU5416 further aggravated PAH in ETTG mice. • Enhanced endothelin system activity could be a causative factor in

  9. Lack of bcr and abr promotes hypoxia-induced pulmonary hypertension in mice.

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    Min Yu

    Full Text Available Bcr and Abr are GTPase activating proteins that specifically downregulate activity of the small GTPase Rac in restricted cell types in vivo. Rac1 is expressed in smooth muscle cells, a critical cell type involved in the pathogenesis of pulmonary hypertension. The molecular mechanisms that underlie hypoxia-associated pulmonary hypertension are not well-defined.Bcr and abr null mutant mice were compared to wild type controls for the development of pulmonary hypertension after exposure to hypoxia. Also, pulmonary arterial smooth muscle cells from those mice were cultured in hypoxia and examined for proliferation, p38 activation and IL-6 production. Mice lacking Bcr or Abr exposed to hypoxia developed increased right ventricular pressure, hypertrophy and pulmonary vascular remodeling. Perivascular leukocyte infiltration in the lungs was increased, and under hypoxia bcr-/- and abr-/- macrophages generated more reactive oxygen species. Consistent with a contribution of inflammation and oxidative stress in pulmonary hypertension-associated vascular damage, Bcr and Abr-deficient animals showed elevated endothelial leakage after hypoxia exposure. Hypoxia-treated pulmonary arterial smooth muscle cells from Bcr- or Abr-deficient mice also proliferated faster than those of wild type mice. Moreover, activated Rac1, phosphorylated p38 and interleukin 6 were increased in these cells in the absence of Bcr or Abr. Inhibition of Rac1 activation with Z62954982, a novel Rac inhibitor, decreased proliferation, p38 phosphorylation and IL-6 levels in pulmonary arterial smooth muscle cells exposed to hypoxia.Bcr and Abr play a critical role in down-regulating hypoxia-induced pulmonary hypertension by deactivating Rac1 and, through this, reducing both oxidative stress generated by leukocytes as well as p38 phosphorylation, IL-6 production and proliferation of pulmonary arterial smooth muscle cells.

  10. Agmatine protects retinal ganglion cells from hypoxia-induced apoptosis in transformed rat retinal ganglion cell line

    Directory of Open Access Journals (Sweden)

    Kim Chan

    2007-10-01

    Full Text Available Abstract Background Agmatine is an endogenous polyamine formed by the decarboxylation of L-arginine. We investigated the protective effects of agmatine against hypoxia-induced apoptosis of immortalized rat retinal ganglion cells (RGC-5. RGC-5 cells were cultured in a closed hypoxic chamber (5% O2 with or without agmatine. Cell viability was determined by lactate dehydrogenase (LDH assay and apoptosis was examined by annexin V and caspase-3 assays. Expression and phosphorylation of mitogen-activated protein kinases (MAPKs; JNK, ERK p44/42, and p38 and nuclear factor-kappa B (NF-κB were investigated by Western immunoblot analysis. The effects of agmatine were compared to those of brain-derived neurotrophic factor (BDNF, a well-known protective neurotrophin for retinal ganglion cells. Results After 48 hours of hypoxic culture, the LDH assay showed 52.3% cell loss, which was reduced to 25.6% and 30.1% when agmatine and BDNF were administered, respectively. This observed cell loss was due to apoptotic cell death, as established by annexin V and caspase-3 assays. Although total expression of MAPKs and NF-κB was not influenced by hypoxic injury, phosphorylation of these two proteins was increased. Agmatine reduced phosphorylation of JNK and NF-κB, while BDNF suppressed phosphorylation of ERK and p38. Conclusion Our results show that agmatine has neuroprotective effects against hypoxia-induced retinal ganglion cell damage in RGC-5 cells and that its effects may act through the JNK and NF-κB signaling pathways. Our data suggest that agmatine may lead to a novel therapeutic strategy to reduce retinal ganglion cell injury related to hypoxia.

  11. Coronary Serum Obtained After Myocardial Infarction Induces Angiogenesis and Microvascular Obstruction Repair. Role of Hypoxia-inducible Factor-1A.

    Science.gov (United States)

    Ríos-Navarro, César; Hueso, Luisa; Miñana, Gema; Núñez, Julio; Ruiz-Saurí, Amparo; Sanz, María Jesús; Cànoves, Joaquin; Chorro, Francisco J; Piqueras, Laura; Bodí, Vicente

    2017-07-24

    Microvascular obstruction (MVO) exerts deleterious effects following acute myocardial infarction (AMI). We investigated coronary angiogenesis induced by coronary serum and the role of hypoxia-inducible factor-1A (HIF-1A) in MVO repair. Myocardial infarction was induced in swine by transitory 90-minute coronary occlusion. The pigs were divided into a control group and 4 AMI groups: no reperfusion, 1minute, 1 week and 1 month after reperfusion. Microvascular obstruction and microvessel density were quantified. The proangiogenic effect of coronary serum drawn from coronary sinus on endothelial cells was evaluated using an in vitro tubulogenesis assay. Circulating and myocardial HIF-1A levels and the effect of in vitro blockade of HIF-1A was assessed. Compared with control myocardium, microvessel density decreased at 90-minute ischemia, and MVO first occurred at 1minute after reperfusion. Both peaked at 1 week and almost completely resolved at 1 month. Coronary serum exerted a neoangiogenic effect on coronary endothelial cells in vitro, peaking at ischemia and 1minute postreperfusion (32 ± 4 and 41 ± 9 tubes vs control: 3 ± 3 tubes; P < .01). Hypoxia-inducible factor-1A increased in serum during ischemia (5-minute ischemia: 273 ± 52 pg/mL vs control: 148 ± 48 pg/mL; P < .01) being present on microvessels of all AMI groups (no reperfusion: 67% ± 5% vs control: 15% ± 17%; P < .01). In vitro blockade of HIF-1A reduced the angiogenic response induced by serum. Coronary serum represents a potent neoangiogenic stimulus even before reperfusion; HIF-1A might be crucial. Coronary neoangiogenesis induced by coronary serum can contribute to understanding the pathophysiology of AMI. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  12. Multi-Vitamin B Supplementation Reverses Hypoxia-Induced Tau Hyperphosphorylation and Improves Memory Function in Adult Mice.

    Science.gov (United States)

    Yu, Lixia; Chen, Yuan; Wang, Weiguang; Xiao, Zhonghai; Hong, Yan

    2016-08-04

    Hypobaric hypoxia (HH) leads to reduced oxygen delivery to brain. It could trigger cognitive dysfunction and increase the risk of dementia including Alzheimer's disease (AD). The present study was undertaken in order to examine whether B vitamins (B6, B12, folate, and choline) could exert protective effects on hypoxia-induced memory deficit and AD related molecular events in mice. Adult male Kunming mice were assigned to five groups: normoxic control, hypoxic model (HH), hypoxia+vitamin B6/B12/folate (HB), hypoxia+choline (HC), hypoxia+vitamin B6/B12/folate+choline (HBC). Mice in the hypoxia, HB, HC, and HBC groups were exposed to hypobaric hypoxia for 8 h/day for 28 days in a decompression chamber mimicking 5500 meters of high altitude. Spatial and passive memories were assessed by radial arm and step-through passive test, respectively. Levels of tau and glycogen synthase kinase (GSK)-3β phosphorylation were detected by western blot. Homocysteine (Hcy) concentrations were determined using enzymatic cycling assay. Mice in the HH group exhibited significant spatial working and passive memory impairment, increased tau phosphorylation at Thr181, Ser262, Ser202/Thr205, and Ser396 in the cortex and hippocampus, and elevated Hcy levels compared with controls. Concomitantly, the levels of Ser9-phosphorylated GSK-3β were significantly decreased in brain after hypoxic treatment. Supplementations of vitamin B6/B12/folate+choline could significantly ameliorate the hypoxia-induced memory deficits, observably decreased Hcy concentrations in serum, and markedly attenuated tau hyperphosphorylation at multiple AD-related sites through upregulating inhibitory Ser9-phosphorylated GSK-3β. Our finding give further insight into combined neuroprotective effects of vitamin B6, B12, folate, and choline on brain against hypoxia.

  13. Effects of YC-1 on hypoxia-inducible factor 1 alpha in hypoxic human bladder transitional carcinoma cell line T24 cells.

    Science.gov (United States)

    Li, Yangle; Zhao, Xiaokun; Tang, Huiting; Zhong, Zhaohui; Zhang, Lei; Xu, Ran; Li, Songchao; Wang, Yi

    2012-01-01

    It was the aim of this study to explore the effects of 3-(5'-hydroxymethyl-2'-furyl)-l-benzyl indazole (YC-1) on transcription activity, cell proliferation and apoptosis of hypoxic human bladder transitional carcinoma cells (BTCC), mediated by hypoxia-inducible factor 1α (HIF-1α). BTCC cell line T24 cells were incubated under normoxic or hypoxic conditions, adding different doses of YC-1. The protein expression of HIF-1α and HIF-1α-mediated genes was detected by Western blotting. RT-PCR was used to detect HIF-1α mRNA expression. Cell proliferation, apoptosis and migration activity were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry and transwell migration assay. The cells were pretreated by two ERK/p38 MAPK pathway-specific inhibitors, PD98059 or SB203580, and then incubated with YC-1 treatment under hypoxic condition. HIF-1α protein expression was detected by Western blotting. Hypoxic T24 cells expressed a higher level of HIF-1α, vascular endothelial growth factor, matrix metalloproteinases-2, B-cell lymphoma/leukemia-2 protein and HIF-1α mRNA compared with normoxic controls, in which the above-mentioned expression was downregulated by YC-1 in a dose-dependent manner. Cell proliferation and migration activity were inhibited while apoptosis was induced by YC-1 under hypoxic condition. Moreover, YC-1-downregulated HIF-1α expression was reversed by PD98059 and SB203580, respectively. YC-1 inhibits HIF-1α and HIF-1α-mediated gene expression, cell proliferation and migration activity and induces apoptosis in hypoxic BTCC. The ERK/p38 MAPK pathway may be involved in YC-1-mediated inhibition of HIF-1α. Copyright © 2011 S. Karger AG, Basel.

  14. Role of nitric oxide in hypoxia-induced hyperventilation and hypothermia: participation of the locus coeruleus

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    Fabris G.

    1999-01-01

    Full Text Available Hypoxia elicits hyperventilation and hypothermia, but the mechanisms involved are not well understood. The nitric oxide (NO pathway is involved in hypoxia-induced hypothermia and hyperventilation, and works as a neuromodulator in the central nervous system, including the locus coeruleus (LC, which is a noradrenergic nucleus in the pons. The LC plays a role in a number of stress-induced responses, but its participation in the control of breathing and thermoregulation is unclear. Thus, in the present study, we tested the hypothesis that LC plays a role in the hypoxia-induced hypothermia and hyperventilation, and that NO is involved in these responses. Electrolytic lesions were performed bilaterally within the LC in awake unrestrained adult male Wistar rats weighing 250-350 g. Body temperature and pulmonary ventilation (VE were measured. The rats were divided into 3 groups: control (N = 16, sham operated (N = 7 and LC lesioned (N = 19, and each group received a saline or an NG-nitro-L-arginine methyl ester (L-NAME, 250 µg/µl intracerebroventricular (icv injection. No significant difference was observed between control and sham-operated rats. Hypoxia (7% inspired O2 caused hyperventilation and hypothermia in both control (from 541.62 ± 35.02 to 1816.18 ± 170.7 and 36.3 ± 0.12 to 34.4 ± 0.09, respectively and LC-lesioned rats (LCLR (from 694.65 ± 63.17 to 2670.29 ± 471.33 and 36 ± 0.12 to 35.3 ± 0.12, respectively, but the increase in VE was higher (P<0.05 and hypothermia was reduced (P<0.05 in LCLR. L-NAME caused no significant change in VE or in body temperature under normoxia, but abolished both the hypoxia-induced hyperventilation and hypothermia. Hypoxia-induced hyperventilation was reduced in LCLR treated with L-NAME. L-NAME also abolished the hypoxia-induced hypothermia in LCLR. The present data indicate that hypoxia-induced hyperventilation and hypothermia may be related to the LC, and that NO is involved in these responses.

  15. Hypoxia-inducible factor-mediated induction of WISP-2 contributes to attenuated progression of breast cancer.

    Science.gov (United States)

    Fuady, Jerry H; Bordoli, Mattia R; Abreu-Rodríguez, Irene; Kristiansen, Glen; Hoogewijs, David; Stiehl, Daniel P; Wenger, Roland H

    2014-01-01

    Hypoxia and the hypoxia-inducible factor (HIF) signaling pathway trigger the expression of several genes involved in cancer progression and resistance to therapy. Transcriptionally active HIF-1 and HIF-2 regulate overlapping sets of target genes, and only few HIF-2 specific target genes are known so far. Here we investigated oxygen-regulated expression of Wnt-1 induced signaling protein 2 (WISP-2), which has been reported to attenuate the progression of breast cancer. WISP-2 was hypoxically induced in low-invasive luminal-like breast cancer cell lines at both the messenger RNA and protein levels, mainly in a HIF-2α-dependent manner. HIF-2-driven regulation of the WISP2 promoter in breast cancer cells is almost entirely mediated by two phylogenetically and only partially conserved functional hypoxia response elements located in a microsatellite region upstream of the transcriptional start site. High WISP-2 tumor levels were associated with increased HIF-2α, decreased tumor macrophage density, and a better prognosis. Silencing WISP-2 increased anchorage-independent colony formation and recovery from scratches in confluent cell layers of normally low-invasive MCF-7 cancer cells. Interestingly, these changes in cancer cell aggressiveness could be phenocopied by HIF-2α silencing, suggesting that direct HIF-2-mediated transcriptional induction of WISP-2 gene expression might at least partially explain the association of high HIF-2α tumor levels with prolonged overall survival of patients with breast cancer.

  16. Oral Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitor Roxadustat (FG-4592) for the Treatment of Anemia in Patients with CKD

    National Research Council Canada - National Science Library

    Provenzano, Robert; Besarab, Anatole; Sun, Chao H; Diamond, Susan A; Durham, John H; Cangiano, Jose L; Aiello, Joseph R; Novak, James E; Lee, Tyson; Leong, Robert; Roberts, Brian K; Saikali, Khalil G; Hemmerich, Stefan; Szczech, Lynda A; Yu, Kin-Hung Peony; Neff, Thomas B

    2016-01-01

    Roxadustat (FG-4592), an oral hypoxia-inducible factor prolyl hydroxylase inhibitor that stimulates erythropoiesis, regulates iron metabolism, and reduces hepcidin, was evaluated in this phase 2b study for safety...

  17. Further insights into the mechanism of hypoxia-induced NFκB. [corrected].

    Science.gov (United States)

    Melvin, Andrew; Mudie, Sharon; Rocha, Sonia

    2011-03-15

    The cellular response to hypoxia relies on the activation of a specific transcriptional program. Although, most of the attention is focused on the transcription factor HIF, other transcription factors are also activated in hypoxia. We have recently described the mechanism for hypoxia induced NFκB. We have demonstrated the crucial dependency on the IKK complex as well as in the upstream IKK kinase TAK1. TAK1 and IKK activation is dependent upon the calcium calmodulin kinase, CaMK2 and requires Ubc13 as the E2 ubiquitin conjugation enzyme. We report a role for XIAP as the possible E3-ubiquitin ligase for this system. Interestingly, hypoxia induced IKK mediated phosphorylation of IκBα, does not lead to degradation. Hypoxia prevents IκBα de-sumoylation of Sumo-2/3 chains on critical lysine residues, normally required for K-48 linked polyubiquitination. Our results define a novel pathway regulating NFκB activation.

  18. Ancient atmospheres and the evolution of oxygen sensing via the hypoxia-inducible factor in metazoans.

    Science.gov (United States)

    Taylor, Cormac T; McElwain, Jennifer C

    2010-10-01

    Metazoan diversification occurred during a time when atmospheric oxygen levels fluctuated between 15 and 30%. The hypoxia-inducible factor (HIF) is a primary regulator of the adaptive transcriptional response to hypoxia. Although the HIF pathway is highly conserved, its complexity increased during periods when atmospheric oxygen concentrations were increasing. Thus atmospheric oxygen levels may have provided a selection force on the development of cellular oxygen-sensing pathways.

  19. Human intermittent hypoxia-induced respiratory plasticity is not caused by inflammation.

    Science.gov (United States)

    Beaudin, Andrew E; Waltz, Xavier; Pun, Matiram; Wynne-Edwards, Katherine E; Ahmed, Sofia B; Anderson, Todd J; Hanly, Patrick J; Poulin, Marc J

    2015-10-01

    Ventilatory instability, reflected by enhanced acute hypoxic (AHVR) and hypercapnic (AHCVR) ventilatory responses is a fundamental component of obstructive sleep apnoea (OSA) pathogenesis. Intermittent hypoxia-induced inflammation is postulated to promote AHVR enhancement in OSA, although the role of inflammation in intermittent hypoxia-induced respiratory changes in humans has not been examined. Thus, this study assessed the role of inflammation in intermittent hypoxia-induced respiratory plasticity in healthy humans.In a double-blind, placebo-controlled, randomised crossover study design, 12 males were exposed to 6 h of intermittent hypoxia on three occasions. Prior to intermittent hypoxia exposures, participants ingested (for 4  days) either placebo or the nonsteroidal anti-inflammatory drugs indomethacin (nonselective cyclooxygenase (COX) inhibitor) and celecoxib (selective COX-2 inhibitor). Pre- and post-intermittent hypoxia resting ventilation, AHVR, AHCVR and serum concentration of the pro-inflammatory cytokine tumour necrosis factor (TNF)-α were assessed.Pre-intermittent hypoxia resting ventilation, AHVR, AHCVR and TNF-α concentrations were similar across all three conditions (p≥0.093). Intermittent hypoxia increased resting ventilation and the AHVR similarly across all conditions (p=0.827), while the AHCVR was increased (p=0.003) and TNF-α was decreased (p=0.006) with only selective COX-2 inhibition.These findings indicate that inflammation does not contribute to human intermittent hypoxia-induced respiratory plasticity. Moreover, selective COX-2 inhibition augmented the AHCVR following intermittent hypoxia exposure, suggesting that selective COX-2 inhibition could exacerbate OSA severity by increasing ventilatory instability. Copyright ©ERS 2015.

  20. Crosstalk between nitric oxide and hypoxia-inducible factor signaling pathways: an update

    OpenAIRE

    Hendrickson MD; Poyton RO

    2015-01-01

    Marina D Hendrickson, Robert O Poyton Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, USA Abstract: Hypoxia-inducible factor-1 (HIF-1) is responsible for cellular adaptations to hypoxia. While oxygen (O2) negatively regulates its stability, many other factors affect HIF-1 stability and activity, including nitric oxide (NO). NO derived from l-arginine and nitrite (NO2–) could nitrosylate or nitrate HIF-1 and multiple proteins involv...

  1. The Protective Effect of Salidroside on Hypoxia-Induced Corpus Cavernosum Smooth Muscle Cell Phenotypic Transformation

    OpenAIRE

    Zhang, Xiang; Zhao, Jian-Feng; Zhao, Fan; Yan, Jun-Feng; Yang, Fan; Huang, Xiao-Jun; Chen, Gang; Fu, Hui-ying; Lv, Bo-Dong

    2017-01-01

    Salidroside, a major active ingredient isolated from Rhodiola rosea, has a long application in Chinese medical history. It has widely demonstrated effects on fatigue, psychological stress, and depression and exhibits potential antihypoxia activity. Emerging evidence shows that hypoxia is an important independent risk factor for erectile dysfunction (ED). The aim of this study was to clarify the effect of salidroside on hypoxia-induced phenotypic transformation of corpus cavernosum smooth musc...

  2. Protein arginine methyltransferase 5 is an essential component of the hypoxia-inducible factor 1 signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ji-Hong; Choi, Yong-Joon; Cho, Chung-Hyun [Department of Pharmacology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 110-799 (Korea, Republic of); Park, Jong-Wan, E-mail: parkjw@snu.ac.kr [Department of Pharmacology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 110-799 (Korea, Republic of)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer HIF-1{alpha} is expressed PRMT5-dependently in hypoxic cancer cells. Black-Right-Pointing-Pointer The HIF-1 regulation of hypoxia-induced genes is attenuated in PRMT5-knocked-down cells. Black-Right-Pointing-Pointer The de novo synthesis of HIF-1{alpha} depends on PRMT5. Black-Right-Pointing-Pointer PRMT5 is involved in the HIF-1{alpha} translation initiated by 5 Prime UTR of HIF-1{alpha} mRNA. -- Abstract: Protein arginine methyltransferase 5 (PRMT5) is an enzyme that transfers one or two methyl groups to the arginine residues of histones or non-histone proteins, and that plays critical roles in cellular processes as diverse as receptor signaling and gene expression. Furthermore, PRMT5 is highly expressed in tumors, where it may be associated with tumor growth. Although much research has been conducted on PRMT5, little is known regarding its role in adaption to hypoxia. As hypoxia-inducible factor 1 (HIF-1) is a key player in hypoxic response, we examined the possible involvement of PRMT5 in the HIF-1 signaling pathway. Of the siRNAs targeting PRMT1-8, only PRMT5 siRNA attenuated the hypoxic induction of HIF-1{alpha} in A549 cells, and this result was reproducible in all three cancer cell lines examined. PRMT5 knock-down also repressed the promoter activities and the transcript levels of HIF-1-governed genes. Mechanistically, de novo synthesis of HIF-1{alpha} protein was reduced in PRMT5-knocked-down A549 cells, and this was rescued by PRMT5 restoration. In contrast, HIF-1{alpha} transcription, RNA processing, and protein stability were unaffected by PRMT5 knock-down. Furthermore, PRMT5 was found to be essential for the HIF-1{alpha} translation initiated by the 5 Prime UTR of HIF-1{alpha} mRNA. Given our results and previous reports, we believe that PRMT5 probably promotes tumor growth by stimulating cell proliferation and by participating in the construction of a tumor-favorable microenvironment via HIF-1 activation.

  3. Antenatal hypoxia induces epigenetic repression of glucocorticoid receptor and promotes ischemic-sensitive phenotype in the developing heart.

    Science.gov (United States)

    Xiong, Fuxia; Lin, Thant; Song, Minwoo; Ma, Qingyi; Martinez, Shannalee R; Lv, Juanxiu; MataGreenwood, Eugenia; Xiao, Daliao; Xu, Zhice; Zhang, Lubo

    2016-02-01

    Large studies in humans and animals have demonstrated a clear association of an adverse intrauterine environment with an increased risk of cardiovascular disease later in life. Yet mechanisms remain largely elusive. The present study tested the hypothesis that gestational hypoxia leads to promoter hypermethylation and epigenetic repression of the glucocorticoid receptor (GR) gene in the developing heart, resulting in increased heart susceptibility to ischemia and reperfusion injury in offspring. Hypoxic treatment of pregnant rats from day 15 to 21 of gestation resulted in a significant decrease of GR exon 14, 15, 16, and 17 transcripts, leading to down-regulation of GR mRNA and protein in the fetal heart. Functional cAMP-response elements (CREs) at -4408 and -3896 and Sp1 binding sites at -3425 and -3034 were identified at GR untranslated exon 1 promoters. Hypoxia significantly increased CpG methylation at the CREs and Sp1 binding sites and decreased transcription factor binding to GR exon 1 promoter, accounting for the repression of the GR gene in the developing heart. Of importance, treatment of newborn pups with 5-aza-2'-deoxycytidine reversed hypoxia-induced promoter methylation, restored GR expression and prevented hypoxia-mediated increase in ischemia and reperfusion injury of the heart in offspring. The findings demonstrate a novel mechanism of epigenetic repression of the GR gene in fetal stress-mediated programming of ischemic-sensitive phenotype in the heart. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. DPP-4 inhibition protects human umbilical vein endothelial cells from hypoxia-induced vascular barrier impairment

    Directory of Open Access Journals (Sweden)

    Naoko Hashimoto

    2017-09-01

    Full Text Available Dipeptidyl peptidase-4 (DPP-4 inhibitors are relatively new class of anti-diabetic drugs. Some protective effects of DPP-4 on cardiovascular disease have been described independently from glucose-lowering effect. However, the detailed mechanisms by which DPP-4 inhibitors exert on endothelial cells remain elusive. The purpose of this research was to determine the effects of DPP-4 inhibitor on endothelial barrier function. Human umbilical vein endothelial cells (HUVECs were cultured and exposed to hypoxia in the presence or absence of Diprotin A, a DPP-4 inhibitor. Immunocytochemistry of vascular endothelial (VE- cadherin showed that jagged VE-cadherin staining pattern induced by hypoxia was restored by treatment with Diprotin A. The increased level of cleaved β-catenin in response to hypoxia was significantly attenuated by Diprotin A, suggesting that DPP-4 inhibition protects endothelial adherens junctions from hypoxia. Subsequently, we found that Diprotin A inhibited hypoxia-induced translocation of NF-κB from cytoplasm to nucleus through decreasing TNF-α expression level. Furthermore, the tube formation assay showed that Diprotin A significantly restored hypoxia-induced decrease in number of tubes by HUVECs. These results suggest that DPP-4 inhibitior protects HUVECs from hypoxia-induced barrier impairment.

  5. Hypoxia-induced deoxycytidine kinase contributes to epithelial proliferation in pulmonary fibrosis.

    Science.gov (United States)

    Weng, Tingting; Poth, Jens M; Karmouty-Quintana, Harry; Garcia-Morales, Luis J; Melicoff, Ernestina; Luo, Fayong; Chen, Ning-yuan; Evans, Christopher M; Bunge, Raquel R; Bruckner, Brian A; Loebe, Matthias; Volcik, Kelly A; Eltzschig, Holger K; Blackburn, Michael R

    2014-12-15

    Idiopathic pulmonary fibrosis (IPF) is a deadly lung disease with few therapeutic options. Apoptosis of alveolar epithelial cells, followed by abnormal tissue repair characterized by hyperplastic epithelial cell formation, is a pathogenic process that contributes to the progression of pulmonary fibrosis. However, the signaling pathways responsible for increased proliferation of epithelial cells remain poorly understood. To investigate the role of deoxycytidine kinase (DCK), an important enzyme for the salvage of deoxynucleotides, in the progression of pulmonary fibrosis. DCK expression was examined in the lungs of patients with IPF and mice exposed to bleomycin. The regulation of DCK expression by hypoxia was studied in vitro and the importance of DCK in experimental pulmonary fibrosis was examined using a DCK inhibitor and alveolar epithelial cell-specific knockout mice. DCK was elevated in hyperplastic alveolar epithelial cells of patients with IPF and in mice exposed to bleomycin. Increased DCK was localized to cells associated with hypoxia, and hypoxia directly induced DCK in alveolar epithelial cells in vitro. Hypoxia-induced DCK expression was abolished by silencing hypoxia-inducible factor 1α and treatment of bleomycin-exposed mice with a DCK inhibitor attenuated pulmonary fibrosis in association with decreased epithelial cell proliferation. Furthermore, DCK expression, and proliferation of epithelial cells and pulmonary fibrosis was attenuated in mice with conditional deletion of hypoxia-inducible factor 1α in the alveolar epithelium. Our findings suggest that the induction of DCK after hypoxia plays a role in the progression of pulmonary fibrosis by contributing to alveolar epithelial cell proliferation.

  6. [Protective effect of salidroside against high altitude hypoxia-induced brain injury in rats].

    Science.gov (United States)

    Dong, Xiaoru; Zhang, Xiangnan; Li, Dan; Li, Bin; Wang, Jiye; Meng, Shanshan; Luo, Wenjing; Zhang, Wenbin

    2015-10-01

    To observe the protective effect of salidroside against brain injury in rats exposed to hypobaric hypoxia, and investigate the molecular mechanism of salidroside in the prevention of hypobaric hypoxia-induced brain injury. Rats were placed in experiment module simulating 6000 m altitude to establish acute hypobaric hypoxia-induced brain injury models. Their respiratory frequency was observed and recorded. Cell apoptosis in the hippocampal dentate gyrus (DG) was detected by TUNEL assay; the expressions of Ras homolog family member A (RhoA), phosphorylated extracellular signal-regulated kinase (p-ERK) and phosphorylated c-Jun N-terminal kinase (p-JNK) were detected by Western blotting. After acute exposure to 6000 m altitude, the respiratory frequency of the rats increased remarkably. The simulation of hypobaric hypoxia induced cell apoptosis in hippocampal DG region, and salidroside intervention inhibited the process of cell apoptosis. The expressions of RhoA, p-ERK, p-JNK decreased after hypobaric hypoxia exposure. Salidroside intervention reversed RhoA expression and raised the levels of p-ERK and p-JNK. Acute exposure to hypobaric hypoxia can induce cell apoptosis in rat hippocampal DG, and salidroside can protect the cells from the exposure-induced apoptosis.

  7. The neurohormone orexin stimulates hypoxia-inducible factor-1 activity

    OpenAIRE

    Sikder, Devanjan; Kodadek, Thomas

    2007-01-01

    Orexin A and Orexin B (also known as hypocretins) are neuropeptides that bind two related G-coupled protein receptors (OXR1 and OXR2) and thus induce wakefulness, food consumption, and locomotion. Conversely, deletion of the orexin gene in mice produces a condition similar to canine and human narcolepsy. Despite the central importance of the orexin system in regulating wakefulness and feeding behavior, little is known about the downstream signaling mechanisms that achieve these effects. In th...

  8. Ascorbic acid, but not dehydroascorbic acid increases intracellular vitamin C content to decrease Hypoxia Inducible Factor -1 alpha activity and reduce malignant potential in human melanoma.

    Science.gov (United States)

    Fischer, Adam P; Miles, Sarah L

    2017-02-01

    Accumulation of hypoxia inducible factor-1 alpha (HIF-1α) in malignant tissue is known to contribute to oncogenic progression and is inversely associated with patient survival. Ascorbic acid (AA) depletion in malignant tissue may contribute to aberrant normoxic activity of HIF-1α. While AA supplementation has been shown to attenuate HIF-1α function in malignant melanoma, the use of dehydroascorbic acid (DHA) as a therapeutic means to increase intracellular AA and modulate HIF-1α function is yet to be evaluated. Here we compared the ability of AA and DHA to increase intracellular vitamin C content and decrease the malignant potential of human melanoma by reducing the activity of HIF-1α. HIF-1α protein accumulation was evaluated by western blot and transcriptional activity was evaluated by reporter gene assay using a HIF-1 HRE-luciferase plasmid. Protein expressions and subcellular localizations of vitamin C transporters were evaluated by western blot and confocal imaging. Intracellular vitamin C content following AA, ascorbate 2-phosphate (A2P), or DHA supplementation was determined using a vitamin C assay. Malignant potential was accessed using a 3D spheroid Matrigel invasion assay. Data was analyzed by One or Two-way ANOVA with Tukey's multiple comparisons test as appropriate with pascorbic acid as an adjuvant cancer therapy remains under investigated. While AA and A2P were capable of modulating HIF-1α protein accumulation/activity, DHA supplementation resulted in minimal intracellular vitamin C activity with decreased ability to inhibit HIF-1α activity and malignant potential in advanced melanoma. Restoring AA dependent regulation of HIF-1α in malignant cells may prove beneficial in reducing chemotherapy resistance and improving treatment outcomes. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Coactivators necessary for transcriptional output of the hypoxia inducible factor, HIF, are directly recruited by ARNT PAS-B.

    Science.gov (United States)

    Partch, Carrie L; Gardner, Kevin H

    2011-05-10

    Hypoxia-inducible factor (HIF) is the key transcriptional effector of the hypoxia response in eukaryotes, coordinating the expression of genes involved in oxygen transport, glycolysis, and angiogenesis to promote adaptation to low oxygen levels. HIF is a basic helix-loop-helix (bHLH)-PAS (PER-ARNT-SIM) heterodimer composed of an oxygen-labile HIF-α subunit and a constitutively expressed aryl hydrocarbon receptor nuclear translocator (ARNT) subunit, which dimerize via basic helix-loop-helix and PAS domains, and recruit coactivators via HIF-α C-terminal transactivation domains. Here we demonstrate that the ARNT PAS-B domain provides an additional recruitment site by binding the coactivator transforming acidic coiled-coil 3 (TACC3) in a step necessary for transcriptional responses to hypoxia. Structural insights from NMR spectroscopy illustrate how this PAS domain simultaneously mediates interactions with HIF-α and TACC3. Finally, mutations on ARNT PAS-B modulate coactivator selectivity and target gene induction by HIF in vivo, demonstrating a bifunctional role for transcriptional regulation by PAS domains within bHLH-PAS transcription factors.

  10. Emerging roles of hypoxia-inducible factors and reactive oxygen species in cancer and pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Shigeo Saito

    2015-06-01

    Full Text Available Eukaryotic organisms require oxygen homeostasis to maintain proper cellular function for survival. During conditions of low oxygen tension (hypoxia, cells activate the transcription of genes that induce an adaptive response, which supplies oxygen to tissues. Hypoxia and hypoxia-inducible factors (HIFs may contribute to the maintenance of putative cancer stem cells, which can continue self-renewal indefinitely and express stemness genes in hypoxic stress environments (stem cell niches. Reactive oxygen species (ROS have long been recognized as toxic by-products of aerobic metabolism that are harmful to living cells, leading to DNA damage, senescence, or cell death. HIFs may promote a cancer stem cell state, whereas the loss of HIFs induces the production of cellular ROS and activation of proteins p53 and p16Ink4a, which lead to tumor cell death and senescence. ROS seem to inhibit HIF regulation in cancer cells. By contrast, controversial data have suggested that hypoxia increases the generation of ROS, which prevents hydroxylation of HIF proteins by inducing their transcription as negative feedback. Moreover, hypoxic conditions enhance the generation of induced pluripotent stem cells (iPSCs. During reprogramming of somatic cells into a PSC state, cells attain a metabolic state typically observed in embryonic stem cells (ESCs. ESCs and iPSCs share similar bioenergetic metabolisms, including decreased mitochondrial number and activity, and induced anaerobic glycolysis. This review discusses the current knowledge regarding the emerging roles of ROS homeostasis in cellular reprogramming and the implications of hypoxic regulation in cancer development.

  11. Asymmetric distribution of hypoxia-inducible factor α regulates dorsoventral axis establishment in the early sea urchin embryo.

    Science.gov (United States)

    Chang, Wei-Lun; Chang, Yi-Cheng; Lin, Kuan-Ting; Li, Han-Ru; Pai, Chih-Yu; Chen, Jen-Hao; Su, Yi-Hsien

    2017-08-15

    Hypoxia signaling is an ancient pathway by which animals can respond to low oxygen. Malfunction of this pathway disturbs hypoxic acclimation and can result in various diseases, including cancers. The role of hypoxia signaling in early embryogenesis remains unclear. Here, we show that in the blastula of the sea urchin Strongylocentrotus purpuratus , hypoxia-inducible factor α (HIFα), the downstream transcription factor of the hypoxia pathway, is localized and transcriptionally active on the future dorsal side. This asymmetric distribution is attributable to its oxygen-sensing ability. Manipulations of the HIFα level entrained the dorsoventral axis, as the side with the higher level of HIFα tends to develop into the dorsal side. Gene expression analyses revealed that HIFα restricts the expression of nodal to the ventral side and activates several genes encoding transcription factors on the dorsal side. We also observed that intrinsic hypoxic signals in the early embryos formed a gradient, which was disrupted under hypoxic conditions. Our results reveal an unprecedented role of the hypoxia pathway in animal development. © 2017. Published by The Company of Biologists Ltd.

  12. Estrogen receptor-dependent attenuation of hypoxia-induced changes in the lung genome of pulmonary hypertension rats.

    Science.gov (United States)

    Frump, Andrea L; Albrecht, Marjorie E; McClintick, Jeanette N; Lahm, Tim

    2017-03-01

    17β-estradiol (E2) exerts complex and context-dependent effects in pulmonary hypertension. In hypoxia-induced pulmonary hypertension (HPH), E2 attenuates lung vascular remodeling through estrogen receptor (ER)-dependent effects; however, ER target genes in the hypoxic lung remain unknown. In order to identify the genome regulated by the E2-ER axis in the hypoxic lung, we performed a microarray analysis in lungs from HPH rats treated with E2 (75 mcg/kg/day) ± ER-antagonist ICI182,780 (3 mg/kg/day). Untreated HPH rats and normoxic rats served as controls. Using a false discovery rate of 10%, we identified a significantly differentially regulated genome in E2-treated versus untreated hypoxia rats. Genes most upregulated by E2 encoded matrix metalloproteinase 8, S100 calcium binding protein A8, and IgA Fc receptor; genes most downregulated by E2 encoded olfactory receptor 63, secreted frizzled-related protein 2, and thrombospondin 2. Several genes affected by E2 changed in the opposite direction after ICI182,780 co-treatment, indicating an ER-regulated genome in HPH lungs. The bone morphogenetic protein antagonist Grem1 (gremlin 1) was upregulated by hypoxia, but found to be among the most downregulated genes after E2 treatment. Gremlin 1 protein was reduced in E2-treated versus untreated hypoxic animals, and ER-blockade abolished the inhibitory effect of E2 on Grem1 mRNA and protein. In conclusion, E2 ER-dependently regulates several genes involved in proliferative and inflammatory processes during hypoxia. Gremlin 1 is a novel target of the E2-ER axis in HPH. Understanding the mechanisms of E2 gene regulation in HPH may allow for selectively harnessing beneficial transcriptional activities of E2 for therapeutic purposes.

  13. Hypoxia-inducible C-to-U coding RNA editing downregulates SDHB in monocytes

    Directory of Open Access Journals (Sweden)

    Bora E. Baysal

    2013-09-01

    Full Text Available Background. RNA editing is a post-transcriptional regulatory mechanism that can alter the coding sequences of certain genes in response to physiological demands. We previously identified C-to-U RNA editing (C136U, R46X which inactivates a small fraction of succinate dehydrogenase (SDH; mitochondrial complex II subunit B gene (SDHB mRNAs in normal steady-state peripheral blood mononuclear cells (PBMCs. SDH is a heterotetrameric tumor suppressor complex which when mutated causes paraganglioma tumors that are characterized by constitutive activation of hypoxia inducible pathways. Here, we studied regulation, extent and cell type origin of SDHB RNA editing.Methods. We used short-term cultured PBMCs obtained from random healthy platelet donors, performed monocyte enrichment by cold aggregation, employed a novel allele-specific quantitative PCR method, flow cytometry, immunologic cell separation, gene expression microarray, database analysis and high-throughput RNA sequencing.Results. While the editing rate is low in uncultured monocyte-enriched PBMCs (average rate 2.0%, range 0.4%–6.3%, n = 42, it is markedly upregulated upon exposure to 1% oxygen tension (average rate 18.2%, range 2.8%–49.4%, n = 14 and during normoxic macrophage differentiation in the presence of serum (average rate 10.1%, range 2.7%–18.8%, n = 17. The normoxic induction of SDHB RNA editing was associated with the development of dense adherent aggregates of monocytes in culture. CD14-positive monocyte isolation increased the percentages of C136U transcripts by 1.25-fold in normoxic cultures (n = 5 and 1.68-fold in hypoxic cultures (n = 4. CD14-negative lymphocytes showed no evidence of SDHB editing. The SDHB genomic DNA remained wild-type during increased RNA editing. Microarray analysis showed expression changes in wound healing and immune response pathway genes as the editing rate increased in normoxic cultures. High-throughput sequencing of SDHB and SDHD transcripts

  14. Hypoxia inducible BHLHB2 is a novel and independent prognostic marker in pancreatic ductal adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weibin; Reiser-Erkan, Carolin; Michalski, Christoph W.; Raggi, Matthias C. [Department of Surgery, Technische Universitaet Muenchen, Munich (Germany); Quan, Liao; Yupei, Zhao [Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Peking (China); Friess, Helmut [Department of Surgery, Technische Universitaet Muenchen, Munich (Germany); Erkan, Mert, E-mail: erkan@chir.med.tu-muenchen.de [Department of Surgery, Technische Universitaet Muenchen, Munich (Germany); Kleeff, Joerg [Department of Surgery, Technische Universitaet Muenchen, Munich (Germany)

    2010-10-22

    cells. Patients with weak/absent nuclear BHLHB2 staining had significantly worse median survival compared to those with strong staining (13 months vs. 27 months, p = 0.03). In a multivariable analysis, BHLHB2 staining was an independent prognostic factor (Hazard-Ratio = 2.348, 95% CI = 1.250-4.411, p = 0.008). Conclusions: Hypoxia-inducible BHLHB2 expression is a novel independent prognostic marker in pancreatic cancer patients and indicates increased chemosensitivity towards gemcitabine.

  15. Role of hypoxia-inducible factor in diabetic myocardial hypertrophy ...

    African Journals Online (AJOL)

    Western blot was used to analyze the expression of some glycolytic proteins, including Glut-1, hexokinase (HXK-2), and enolase, while apoptosis of H9C2 was determined by flow cytometry. Results: PE caused hypertrophy in H9C2, which was ameliorated by HIF-1α. Compared to normal, under prolonged high glucose, the ...

  16. Mechanism of hypoxia-induced NF-kappaB.

    Science.gov (United States)

    Culver, Carolyn; Sundqvist, Anders; Mudie, Sharon; Melvin, Andrew; Xirodimas, Dimitris; Rocha, Sonia

    2010-10-01

    NF-κB activation is a critical component in the transcriptional response to hypoxia. However, the underlying mechanisms that control its activity under these conditions are unknown. Here we report that under hypoxic conditions, IκB kinase (IKK) activity is induced through a calcium/calmodulin-dependent kinase 2 (CaMK2)-dependent pathway distinct from that for other common inducers of NF-κB. This process still requires IKK and the IKK kinase TAK1, like that for inflammatory inducers of NF-κB, but the TAK1-associated proteins TAB1 and TAB2 are not essential. IKK complex activation following hypoxia requires Ubc13 but not the recently identified LUBAC (linear ubiquitin chain assembly complex) ubiquitin conjugation system. In contrast to the action of other NF-κB inducers, IKK-mediated phosphorylation of IκBα does not result in its degradation. We show that this results from IκBα sumoylation by Sumo-2/3 on critical lysine residues, normally required for K-48-linked polyubiquitination. Furthermore, inhibition of specific Sumo proteases is sufficient to release RelA from IκBα and activate NF-κB target genes. These results define a novel pathway regulating NF-κB activation, important to its physiological role in human health and disease.

  17. Mechanism of Hypoxia-Induced NF-κB▿ †

    Science.gov (United States)

    Culver, Carolyn; Sundqvist, Anders; Mudie, Sharon; Melvin, Andrew; Xirodimas, Dimitris; Rocha, Sonia

    2010-01-01

    NF-κB activation is a critical component in the transcriptional response to hypoxia. However, the underlying mechanisms that control its activity under these conditions are unknown. Here we report that under hypoxic conditions, IκB kinase (IKK) activity is induced through a calcium/calmodulin-dependent kinase 2 (CaMK2)-dependent pathway distinct from that for other common inducers of NF-κB. This process still requires IKK and the IKK kinase TAK1, like that for inflammatory inducers of NF-κB, but the TAK1-associated proteins TAB1 and TAB2 are not essential. IKK complex activation following hypoxia requires Ubc13 but not the recently identified LUBAC (linear ubiquitin chain assembly complex) ubiquitin conjugation system. In contrast to the action of other NF-κB inducers, IKK-mediated phosphorylation of IκBα does not result in its degradation. We show that this results from IκBα sumoylation by Sumo-2/3 on critical lysine residues, normally required for K-48-linked polyubiquitination. Furthermore, inhibition of specific Sumo proteases is sufficient to release RelA from IκBα and activate NF-κB target genes. These results define a novel pathway regulating NF-κB activation, important to its physiological role in human health and disease. PMID:20696840

  18. Hypoxia induces adipogenic differentitation of myoblastic cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Itoigawa, Yoshiaki [Tohoku University School of Medicine, Sendai (Japan); Juntendo University School of Medicine, Tokyo (Japan); Kishimoto, Koshi N., E-mail: kishimoto@med.tohoku.ac.jp [Tohoku University School of Medicine, Sendai (Japan); Okuno, Hiroshi; Sano, Hirotaka [Tohoku University School of Medicine, Sendai (Japan); Kaneko, Kazuo [Juntendo University School of Medicine, Tokyo (Japan); Itoi, Eiji [Tohoku University School of Medicine, Sendai (Japan)

    2010-09-03

    Research highlights: {yields} C2C12 and G8 myogenic cell lines treated by hypoxia differentiate into adipocytes. {yields} The expression of C/EBP{beta}, {alpha} and PPAR{gamma} were increased under hypoxia. {yields} Myogenic differentiation of C2C12 was inhibited under hypoxia. -- Abstract: Muscle atrophy usually accompanies fat accumulation in the muscle. In such atrophic conditions as back muscles of kyphotic spine and the rotator cuff muscles with torn tendons, blood flow might be diminished. It is known that hypoxia causes trans-differentiation of mesenchymal stem cells derived from bone marrow into adipocytes. However, it has not been elucidated yet if hypoxia turned myoblasts into adipocytes. We investigated adipogenesis in C2C12 and G8 murine myogenic cell line treated by hypoxia. Cells were also treated with the cocktail of insulin, dexamethasone and IBMX (MDI), which has been known to inhibit Wnt signaling and promote adipogenesis. Adipogenic differentiation was seen in both hypoxia and MDI. Adipogenic marker gene expression was assessed in C2C12. CCAAT/enhancer-binding protein (C/EBP) {beta}, {alpha} and peroxisome proliferator activating receptor (PPAR) {gamma} were increased by both hypoxia and MDI. The expression profile of Wnt10b was different between hypoxia and MDI. The mechanism for adipogenesis of myoblasts in hypoxia might be regulated by different mechanism than the modification of Wnt signaling.

  19. Hypoxia induced E-cadherin involving regulators of Hippo pathway due to HIF-1α stabilization/nuclear translocation in bone metastasis from breast carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Maroni, Paola [Istituto Ortopedico Galeazzi, IRCCS, Milano (Italy); Matteucci, Emanuela [Dipartiimento di Scienze Biomediche per la Salute, Molecular Pathology Laboratory, Università degli Studi di Milano, Milano (Italy); Drago, Lorenzo; Banfi, Giuseppe [Istituto Ortopedico Galeazzi, IRCCS, Milano (Italy); Dipartiimento di Scienze Biomediche per la Salute, Molecular Pathology Laboratory, Università degli Studi di Milano, Milano (Italy); Bendinelli, Paola [Dipartiimento di Scienze Biomediche per la Salute, Molecular Pathology Laboratory, Università degli Studi di Milano, Milano (Italy); Desiderio, Maria Alfonsina, E-mail: a.desiderio@unimi.it [Dipartiimento di Scienze Biomediche per la Salute, Molecular Pathology Laboratory, Università degli Studi di Milano, Milano (Italy)

    2015-01-15

    The present study deals with the molecular mechanisms involved in the regulation of E-cadherin expression under hypoxia, because the adjustment of the amount of E-cadherin due to physical stimuli of the microenvironment might influence the colonization of metastasis to skeleton. We analyzed the effect of 1% oxygen tension, that is similar to that encountered in the bone marrow by metastatic cells spreading from breast carcinoma. The purpose was to evaluate the hypoxia-orchestrated control of E-cadherin transactivation via hypoxia inducible factor-1 (HIF-1) and peroxisome proliferator activated receptor-γ (PPARγ), and the involvement of Hippo pathway members, as regulators of transcription factors. To give a translational significance to the study, we took into consideration human pair-matched ductal breast carcinoma and bone metastasis: E-cadherin and Wwox were expressed in bone metastasis but not in breast carcinoma, while HIF-1α and TAZ seemed localized principally in nuclei of metastasis and were found in all cell compartments of breast carcinoma. A close examination of the regulatory mechanisms underlying E-cadherin expression in bone metastasis was done in 1833 clone derived from MDA-MB231 cells. Hypoxia induced E-cadherin only in 1833 clone, but not in parental cells, through HIF-1 and PPARγ activities, while Wwox decreased. Since Wwox was highly expressed in bone metastasis, the effect of ectopic Wwox was evaluated, and we showed E-cadherin transactivation and enhanced invasiveness in WWOX transfected 1833 cells. Also, hypoxia was additive with ectopic Wwox remarkably enhancing HIF-1α nuclear shuttle and accumulation due to the lengthening of the half-life of HIF-1α protein; under this experimental condition HIF-1α appeared as a slower migrated band compared with control, in agreement with the phosphorylation state. The in vitro data strongly supported the almost exclusive presence of HIF-1α in nuclei of human-bone metastasis. Thus, we identified

  20. A3 Adenosine Receptors Modulate Hypoxia-inducible Factor-1a Expression in Human A375 Melanoma Cells

    Directory of Open Access Journals (Sweden)

    Stefania Merighi

    2005-10-01

    Full Text Available Hypoxia-inducible factor-1 (HIF-1 is a key regulator of genes crucial to many aspects of cancer biology. The purine nucleoside, adenosine, accumulates within many tissues under hypoxic conditions, including that of tumors. Because the levels of both HIF-1 and adenosine are elevated within the hypoxic environment of solid tumors, we investigated whether adenosine may regulate HIF-1. Here we show that, under hypoxic conditions (< 2% 02, adenosine upregulates HIF-1α protein expression in a dose-dependent and timedependent manner, exclusively through the A3 receptor subtype. The response to adenosine was generated at the cell surface because the inhibition of A3 receptor expression, by using small interfering RNA, abolished nucleoside effects. A3 receptor stimulation in hypoxia also increases angiopoietin-2 (Ang-2 protein accumulation through the induction of HIF-1α. In particular, we found that A3 receptor stimulation activates p44/p42 and p38 mitogen-activated protein kinases, which are required for A3-induced increase of HIF-1a and Ang-2. Collectively, these results suggest a cooperation between hypoxic and adenosine signals that ultimately may lead to the increase in HIF-1-mediated effects in cancer cells.

  1. Transient ureteral obstruction prevents against kidney ischemia/reperfusion injury via hypoxia-inducible factor (HIF-2α activation.

    Directory of Open Access Journals (Sweden)

    Shun Zhang

    Full Text Available Although the protective effect of transient ureteral obstruction (UO prior to ischemia on subsequent renal ischemia/reperfusion (I/R injury has been documented, the underlying molecular mechanism remains to be understood. We showed in the current study that 24 h of UO led to renal tubular hypoxia in the ipsilateral kidney in mice, with the accumulation of hypoxia-inducible factor (HIF-2α, which lasted for a week after the release of UO. To address the functions of HIF-2α in UO-mediated protection of renal IRI, we utilized the Mx-Cre/loxP recombination system to knock out target genes. Inactivation of HIF-2α, but not HIF-1α blunted the renal protective effects of UO, as demonstrated by much higher serum creatinine level and severer histological damage. UO failed to prevent postischemic neutrophil infiltration and apoptosis induction in HIF-2α knockout mice, which also diminished the postobstructive up-regulation of the protective molecule, heat shock protein (HSP-27. The renal protective effects of UO were associated with the improvement of the postischemic recovery of intra-renal microvascular blood flow, which was also dependent on the activation of HIF-2α. Our results demonstrated that UO protected the kidney via activation of HIF-2α, which reduced tubular damages via preservation of adequate renal microvascular perfusion after ischemia. Thus, preconditional HIF-2α activation might serve as a novel therapeutic strategy for the treatment of ischemic acute renal failure.

  2. Hypoxia-inducible factor-1 plays a role in phosphate-induced vascular smooth muscle cell calcification.

    Science.gov (United States)

    Mokas, Sophie; Larivière, Richard; Lamalice, Laurent; Gobeil, Stéphane; Cornfield, David N; Agharazii, Mohsen; Richard, Darren E

    2016-09-01

    Medial vascular calcification is a common complication of chronic kidney disease (CKD). Although elevated inorganic phosphate stimulates vascular smooth muscle cell (VSMC) osteogenic transdifferentiation and calcification, the mechanisms involved in their calcification during CKD are not fully defined. Because hypoxic gene activation is linked to CKD and stimulates bone cell osteogenic differentiation, we used in vivo and in vitro rodent models to define the role of hypoxic signaling during elevated inorganic phosphate-induced VSMC calcification. Cell mineralization studies showed that elevated inorganic phosphate rapidly induced VSMC calcification. Hypoxia strongly enhanced elevated inorganic phosphate-induced VSMC calcification and osteogenic transdifferentiation, as seen by osteogenic marker expression. Hypoxia-inducible factor-1 (HIF-1), the key hypoxic transcription factor, was essential for enhanced VSMC calcification. Targeting HIF-1 expression in murine VSMC blocked calcification in hypoxia with elevated inorganic phosphate while HIF-1 activators, including clinically used FG-4592/Roxadustat, recreated a procalcifying environment. Elevated inorganic phosphate rapidly activated HIF-1, even in normal oxygenation; an effect mediated by HIF-1α subunit stabilization. Thus, hypoxia synergizes with elevated inorganic phosphate to enhance VSMC osteogenic transdifferentiation. Our work identifies HIF-1 as an early CKD-related pathological event, prospective marker, and potential target against vascular calcification in CKD-relevant conditions. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  3. Hypoxia-inducible factor-2α stabilizes the von Hippel-Lindau (VHL) disease suppressor, Myb-related protein 2.

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    Okumura, Fumihiko; Joo-Okumura, Akiko; Nakatsukasa, Kunio; Kamura, Takumi

    2017-01-01

    Ubiquitin ligase von Hippel-Lindau tumor suppressor (pVHL) negatively regulates protein levels of hypoxia-inducible factor-α (HIF-α). Loss of pVHL causes HIF-α accumulation, which contributes to the pathogenesis of von Hippel-Lindau (VHL) disease. In contrast, v-Myb avian myeloblastosis viral oncogene homolog-like 2 (MYBL2; B-Myb), a transcription factor, prevents VHL pathogenesis by regulating gene expression of HIF-independent pathways. Both HIF-α and B-Myb are targets of pVHL-mediated polyubiquitination and proteasomal degradation. Here, we show that knockdown of HIF-2α induces downregulation of B-Myb in 786-O cells, which are deficient in pVHL, and this downregulation is prevented by proteasome inhibition. In the presence of pVHL and under hypoxia-like conditions, B-Myb and HIF-2α are both upregulated, and the upregulation of B-Myb requires expression of HIF-2α. We also show that HIF-2α and B-Myb interact in the nucleus, and this interaction is mediated by the central region of HIF-2α and the C-terminal region of B-Myb. These data indicate that oncogenic HIF-2α stabilizes B-Myb to suppress VHL pathogenesis.

  4. Intestine-specific Disruption of Hypoxia-inducible Factor (HIF)-2α Improves Anemia in Sickle Cell Disease.

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    Das, Nupur; Xie, Liwei; Ramakrishnan, Sadeesh K; Campbell, Andrew; Rivella, Stefano; Shah, Yatrik M

    2015-09-25

    Sickle cell disease (SCD) is caused by genetic defects in the β-globin chain. SCD is a frequently inherited blood disorder, and sickle cell anemia is a common type of hemoglobinopathy. During anemia, the hypoxic response via the transcription factor hypoxia-inducible factor (HIF)-2α is highly activated in the intestine and is essential in iron absorption. Intestinal disruption of HIF-2α protects against tissue iron accumulation in iron overload anemias. However, the role of intestinal HIF-2α in regulating anemia in SCD is currently not known. Here we show that in mouse models of SCD, disruption of intestinal HIF-2α significantly decreased tissue iron accumulation. This was attributed to a decrease in intestinal iron absorptive genes, which were highly induced in a mouse model of SCD. Interestingly, disruption of intestinal HIF-2α led to a robust improvement in anemia with an increase in RBC, hemoglobin, and hematocrit. This was attributed to improvement in RBC survival, hemolysis, and insufficient erythropoiesis, which is evident from a significant decrease in serum bilirubin, reticulocyte counts, and serum erythropoietin following intestinal HIF-2α disruption. These data suggest that targeting intestinal HIF-2α has a significant therapeutic potential in SCD pathophysiology. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. The Hypoxia-Inducible Factor Pathway, Prolyl Hydroxylase Domain Protein Inhibitors, and Their Roles in Bone Repair and Regeneration

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    Lihong Fan

    2014-01-01

    Full Text Available Hypoxia-inducible factors (HIFs are oxygen-dependent transcriptional activators that play crucial roles in angiogenesis, erythropoiesis, energy metabolism, and cell fate decisions. The group of enzymes that can catalyse the hydroxylation reaction of HIF-1 is prolyl hydroxylase domain proteins (PHDs. PHD inhibitors (PHIs activate the HIF pathway by preventing degradation of HIF-α via inhibiting PHDs. Osteogenesis and angiogenesis are tightly coupled during bone repair and regeneration. Numerous studies suggest that HIFs and their target gene, vascular endothelial growth factor (VEGF, are critical regulators of angiogenic-osteogenic coupling. In this brief perspective, we review current studies about the HIF pathway and its role in bone repair and regeneration, as well as the cellular and molecular mechanisms involved. Additionally, we briefly discuss the therapeutic manipulation of HIFs and VEGF in bone repair and bone tumours. This review will expand our knowledge of biology of HIFs, PHDs, PHD inhibitors, and bone regeneration, and it may also aid the design of novel therapies for accelerating bone repair and regeneration or inhibiting bone tumours.

  6. Anti-angiogenic and anti-tumor activity of Bavachinin by targeting hypoxia-inducible factor-1α.

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    Nepal, Manoj; Choi, Hwa Jung; Choi, Bo-Yun; Kim, Se Lim; Ryu, Jae-Ha; Kim, Do Hee; Lee, Young-Hoon; Soh, Yunjo

    2012-09-15

    Hypoxia-inducible factor-1 (HIF-1) consists of two subunits, the HIF-1β, which is constitutively expressed, and HIF-1α, which is oxygen-responsive. HIF-1α is over-expressed in response to hypoxia, increasing transcriptional activity linked to tumor progression, angiogenesis, metastasis, and invasion. This study aimed to demonstrate that the natural compound, Bavachinin, has potent anti-angiogenic activity in vitro and in vivo. Bavachinin inhibited increases in HIF-1α activity in human KB carcinoma (HeLa cell derivative) and human HOS osteosarcoma cells under hypoxia in a concentration-dependent manner, probably by enhancing the interaction between von Hippel-Lindau (VHL) and HIF-1α. Furthermore, Bavachinin decreased transcription of genes associated with angiogenesis and energy metabolism that are regulated by HIF-1, such as vascular endothelial growth factors (VEGF), Glut 1 and Hexokinase 2. Bavachinin also inhibited tube formation in human umbilical vein endothelial cells (HUVECs) as well as in vitro migration of KB cells. In vivo studies showed that injecting Bavachinin thrice weekly for four weeks significantly reduced tumor volume and CD31 expression in nude mice with KB xenografts. These data indicate that Bavachinin could be used as a therapeutic agent for inhibiting tumor angiogenesis. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Interactions between nitric oxide and hypoxia-inducible factor signaling pathways in inflammatory disease.

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    Olson, Nels; van der Vliet, Albert

    2011-08-01

    Induction and activation of nitric oxide (NO) synthases (NOS) and excessive production of NO are common features of almost all diseases associated with infection and acute or chronic inflammation, although the contribution of NO to the pathophysiology of these diseases is highly multifactorial and often still a matter of controversy. Because of its direct impact on tissue oxygenation and cellular oxygen (O(2)) consumption and re-distribution, the ability of NO to regulate various aspects of hypoxia-induced signaling has received widespread attention. Conditions of tissue hypoxia and the activation of hypoxia-inducible factors (HIF) have been implicated in hypoxia or in cancer biology, but are also being increasingly recognized as important features of acute and chronic inflammation. Thus, the activation of HIF transcription factors has been increasingly implicated in inflammatory diseases, and recent studies have indicated its critical importance in regulating phagocyte function, inflammatory mediator production, and regulation of epithelial integrity and repair processes. Finally, HIF also appears to contribute to important features of tissue fibrosis and epithelial-to-mesenchymal transition, processes that are associated with tissue remodeling in various non-malignant chronic inflammatory disorders. In this review, we briefly summarize the current state of knowledge with respect to the general mechanisms involved in HIF regulation and the impact of NO on HIF activation. Secondly, we will summarize the major recent findings demonstrating a role for HIF signaling in infection, inflammation, and tissue repair and remodeling, and will address the involvement of NO. The growing interest in hypoxia-induced signaling and its relation with NO biology is expected to lead to further insights into the complex roles of NO in acute or chronic inflammatory diseases and may point to the importance of HIF signaling as key feature of NO-mediated events during these disorders

  8. Iptakalim attenuates hypoxia-induced pulmonary arterial hypertension in rats by endothelial function protection.

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    Zhu, Rong; Bi, Li-Qing; Wu, Su-Ling; Li, Lan; Kong, Hui; Xie, Wei-Ping; Wang, Hong; Meng, Zi-Li

    2015-08-01

    The present study aimed to investigate the protective effects of iptakalim, an adenosine triphosphate (ATP)-sensitive potassium channel opener, on the inflammation of the pulmonary artery and endothelial cell injury in a hypoxia-induced pulmonary arterial hypertension (PAH) rat model. Ninety-six Sprague-Dawley rats were placed into normobaric hypoxia chambers for four weeks and were treated with iptakalim (1.5 mg/kg/day) or saline for 28 days. The right ventricle systolic pressures (RVSP) were measured and small pulmonary arterial morphological alterations were analyzed with hematoxylin and eosin staining. Enzyme-linked immunosorbent assay (ELISA) was performed to analyze the content of interleukin (IL)-1β and IL-10. Immunohistochemical analysis for ED1(+) monocytes was performed to detect the inflammatory cells surrounding the pulmonary arterioles. Western blot analysis was performed to analyze the expression levels of platelet endothelial cell adhesion molecule-1 (PECAM-1) and endothelial nitric oxide synthase (eNOS) in the lung tissue. Alterations in small pulmonary arteriole morphology and the ultrastructure of pulmonary arterial endothelial cells were observed via light and transmission electron microscopy, respectively. Iptakalim significantly attenuated the increase in mean pulmonary artery pressure, RVSP, right ventricle to left ventricle plus septum ratio and small pulmonary artery wall remodeling in hypoxia-induced PAH rats. Iptakalim also prevented an increase in IL-1β and a decrease in IL-10 in the peripheral blood and lung tissue, and alleviated inflammatory cell infiltration in hypoxia-induced PAH rats. Furthermore, iptakalim enhanced PECAM-1 and eNOS expression and prevented the endothelial cell injury induced by hypoxic stimuli. Iptakalim suppressed the pulmonary arteriole and systemic inflammatory responses and protected against the endothelial damage associated with the upregulation of PECAM-1 and eNOS, suggesting that iptakalim may represent a

  9. HIF-1α-l-PGDS-PPARγ regulates hypoxia-induced ANP secretion in beating rat atria.

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    Li, Xiang; Zhang, Ying; Zhang, Bo; Liu, Xia; Hong, Lan; Liu, Li-Ping; Wu, Cheng-Zhe; Cui, Xun

    2018-01-01

    Lipocalin-type prostaglandin D synthase (L-PGDS) and peroxisome proliferator activated receptor γ (PPARγ) play important roles in cardiovascular diseases. Nevertheless, effects of hypoxia-inducible factor 1α (HIF-1α) on L-PGDS and PPARγ protein levels and its role in hypoxia-induced atrial natriuretic peptide (ANP) secretion are unclear. In perfused beating rat atria, we observed that hypoxia significantly increased HIF-1α protein levels and stimulated ANP secretion, while upregulating L-PGDS. Hypoxia-induced ANP secretion was clearly attenuated by HIF-1α antagonist 2-methoxyestradiol, downregulating both HIF-1α and L-PGDS protein levels. It was also attenuated by L-PGDS antagonists, AT-56 and HQL-49, downregulating L-PGDS protein levels. In addition, hypoxia-induced ANP secretion was accompanied by increased PPARγ protein levels and was strongly attenuated by PPARγ antagonist GW9662. Hypoxia-induced increase in atrial PPARγ protein levels were dramatically inhibited by both 2-methoxyestradiol and AT-56. These results indicated that hypoxia promotes ANP secretion, at least in part, by activating HIF-1α-l-PGDS-PPARγ signaling in beating rat atria. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Pien Tze Huang Inhibits Hypoxia-Induced Angiogenesis via HIF-1α/VEGF-A Pathway in Colorectal Cancer

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    Hongwei Chen

    2015-01-01

    Full Text Available Hypoxia-induced angiogenesis plays an important role in the development and metastasis of solid tumors and is highly regulated by HIF-1α/VEGF-A pathway. Therefore, inhibiting tumor angiogenesis via suppression of HIF-1α/VEGF-A signaling represents a promising strategy for anticancer treatment. As a traditional Chinese medicine formula, Pien Tze Huang (PZH has long been used as a folk remedy for cancer in China and Southeast Asia. Previously, we reported that PZH inhibits colorectal cancer (CRC growth both in vivo and in vitro. To elucidate the antitumor mechanisms of PZH, in the present study we used human umbilical vein endothelial cells (HUVEC and colorectal carcinoma HCT-8 cells to evaluate the effects of PZH on hypoxia-induced angiogenesis and investigated the underlying molecular mechanisms. We found that PZH could inhibit hypoxia-induced migration and tube formation of HUVEC cells in a dose-dependent manner, although the low concentrations of PZH had no effect on HUVEC viability. Moreover, PZH inhibited hypoxia-induced activation of HIF-1α signaling and the expression of VEGF-A and/or VEGFR2 in both HCT-8 and HUVEC cells. Collectively, our findings suggest that PZH can inhibit hypoxia-induced tumor angiogenesis via suppression of HIF-1α/VEGF-A pathway.

  11. Hypoxia-Induced Collagen Synthesis of Human Lung Fibroblasts by Activating the Angiotensin System

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    Shan-Shan Liu

    2013-12-01

    Full Text Available The exact molecular mechanism that mediates hypoxia-induced pulmonary fibrosis needs to be further clarified. The aim of this study was to explore the effect and underlying mechanism of angiotensin II (Ang II on collagen synthesis in hypoxic human lung fibroblast (HLF cells. The HLF-1 cell line was used for in vitro studies. Angiotensinogen (AGT, angiotensin converting enzyme (ACE, angiotensin II type 1 receptor (AT1R and angiotensin II type 2 receptor (AT2R expression levels in human lung fibroblasts were analysed using real-time polymerase chain reaction (RT-PCR after hypoxic treatment. Additionally, the collagen type I (Col-I, AT1R and nuclear factor κappaB (NF-κB protein expression levels were detected using Western blot analysis, and NF-κB nuclear translocation was measured using immunofluorescence localization analysis. Ang II levels in HLF-1 cells were measured with an enzyme-linked immunosorbent assay (ELISA. We found that hypoxia increased Col-I mRNA and protein expression in HLF-1 cells, and this effect could be inhibited by an AT1R or AT2R inhibitor. The levels of NF-κB, RAS components and Ang II production in HLF-1 cells were significantly increased after the hypoxia exposure. Hypoxia or Ang II increased NF-κB-p50 protein expression in HLF-1 cells, and the special effect could be inhibited by telmisartan (TST, an AT1R inhibitor, and partially inhibited by PD123319, an AT2R inhibitor. Importantly, hypoxia-induced NF-κB nuclear translocation could be nearly completely inhibited by an AT1R or AT2R inhibitor. Furthermore pyrrolidine dithiocarbamate (PDTC, a NF-κB blocker, abolished the expression of hypoxia-induced AT1R and Col-I in HLF-1 cells. Our results indicate that Ang II-mediated NF-κB signalling via ATR is involved in hypoxia-induced collagen synthesis in human lung fibroblasts.

  12. Asymmetric dimethyl arginine induces pulmonary vascular dysfunction via activation of signal transducer and activator of transcription 3 and stabilization of hypoxia-inducible factor 1-alpha.

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    Pekarova, Michaela; Koudelka, Adolf; Kolarova, Hana; Ambrozova, Gabriela; Klinke, Anna; Cerna, Anna; Kadlec, Jaroslav; Trundova, Maria; Sindlerova Svihalkova, Lenka; Kuchta, Radek; Kuchtova, Zdenka; Lojek, Antonin; Kubala, Lukas

    2015-10-01

    Pulmonary hypertension (PH), associated with imbalance in vasoactive mediators and massive remodeling of pulmonary vasculature, represents a serious health complication. Despite the progress in treatment, PH patients typically have poor prognoses with severely affected quality of life. Asymmetric dimethyl arginine (ADMA), endogenous inhibitor of endothelial nitric oxide synthase (eNOS), also represents one of the critical regulators of pulmonary vascular functions. The present study describes a novel mechanism of ADMA-induced dysfunction in human pulmonary endothelial and smooth muscle cells. The effect of ADMA was compared with well-established model of hypoxia-induced pulmonary vascular dysfunction. It was discovered for the first time that ADMA induced the activation of signal transducer and activator of transcription 3 (STAT3) and stabilization of hypoxia inducible factor 1α (HIF-1α) in both types of cells, associated with drastic alternations in normal cellular functions (e.g., nitric oxide production, cell proliferation/Ca(2+) concentration, production of pro-inflammatory mediators, and expression of eNOS, DDAH1, and ICAM-1). Additionally, ADMA significantly enhanced the hypoxia-mediated increase in the signaling cascades. In summary, increased ADMA may lead to manifestation of PH phenotype in human endothelial and smooth muscle cells via the STAT3/HIF-1α cascade. Therefore this signaling pathway represents the potential pathway for future clinical interventions in PH. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Hypoxia-inducible factor-mediated induction of WISP-2 contributes to attenuated progression of breast cancer

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    Fuady JH

    2014-03-01

    Full Text Available Jerry H Fuady,1,* Mattia R Bordoli,1,* Irene Abreu-Rodríguez,1,* Glen Kristiansen,2 David Hoogewijs,1,** Daniel P Stiehl,1,** Roland H Wenger1,**1Institute of Physiology and Zurich Center for Human Physiology, University of Zurich, Zurich, Switzerland; 2University Hospital Bonn, Institute of Pathology, Bonn, Germany*,**These authors contributed equally to this workAbstract: Hypoxia and the hypoxia-inducible factor (HIF signaling pathway trigger the expression of several genes involved in cancer progression and resistance to therapy. Transcriptionally active HIF-1 and HIF-2 regulate overlapping sets of target genes, and only few HIF-2 specific target genes are known so far. Here we investigated oxygen-regulated expression of Wnt-1 induced signaling protein 2 (WISP-2, which has been reported to attenuate the progression of breast cancer. WISP-2 was hypoxically induced in low-invasive luminal-like breast cancer cell lines at both the messenger RNA and protein levels, mainly in a HIF-2α-dependent manner. HIF-2-driven regulation of the WISP2 promoter in breast cancer cells is almost entirely mediated by two phylogenetically and only partially conserved functional hypoxia response elements located in a microsatellite region upstream of the transcriptional start site. High WISP-2 tumor levels were associated with increased HIF-2α, decreased tumor macrophage density, and a better prognosis. Silencing WISP-2 increased anchorage-independent colony formation and recovery from scratches in confluent cell layers of normally low-invasive MCF-7 cancer cells. Interestingly, these changes in cancer cell aggressiveness could be phenocopied by HIF-2α silencing, suggesting that direct HIF-2-mediated transcriptional induction of WISP-2 gene expression might at least partially explain the association of high HIF-2α tumor levels with prolonged overall survival of patients with breast cancer.Keywords: invasion, metastasis, motility, oxygen, tumor, transcriptional

  14. Induction of gastrin expression in gastrointestinal cells by hypoxia or cobalt is independent of hypoxia-inducible factor (HIF).

    Science.gov (United States)

    Xiao, Lin; Kovac, Suzana; Chang, Mike; Shulkes, Arthur; Baldwin, Graham S; Patel, Oneel

    2012-07-01

    Gastrin and its precursors have been shown to promote mitogenesis and angiogenesis in gastrointestinal tumors. Hypoxia stimulates tumor growth, but its effect on gastrin gene regulation has not been examined in detail. Here we have investigated the effect of hypoxia on the transcription of the gastrin gene in human gastric cancer (AGS) cells. Gastrin mRNA was measured by real-time PCR, gastrin peptides were measured by RIA, and gastrin promoter activity was measured by dual-luciferase reporter assay. Exposure to a low oxygen concentration (1%) increased gastrin mRNA concentrations in wild-type AGS cells (AGS) and in AGS cells overexpressing the gastrin receptor (AGS-cholecystokinin receptor 2) by 2.1 ± 0.4- and 4.1 ± 0.3-fold (P gastrin promoter activity in AGS cells by 2.4 ± 0.3-fold (P gastrin promoter of the putative binding sites for the transcription factor hypoxia-inducible factor 1 (HIF-1) or knockdown of either the HIF-1α or HIF-1β subunit did not affect gastrin promoter inducibility under hypoxia indicated that the hypoxic activation of the gastrin gene is likely HIF independent. Mutational analysis of previously identified Sp1 regulatory elements in the gastrin promoter also failed to abrogate the induction of promoter activity by hypoxia. The observations that hypoxia up-regulates the gastrin gene in AGS cells by HIF-independent mechanisms, and that this effect is enhanced by the presence of gastrin receptors, provide potential targets for gastrointestinal cancer therapy.

  15. A critical role of interleukin-10 in modulating hypoxia-induced preeclampsia-like disease in mice.

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    Lai, Zhongbin; Kalkunte, Satyan; Sharma, Surendra

    2011-03-01

    Hypoxia has been implicated in the pathogenesis of preeclampsia, a hypertensive disorder of pregnancy. However, in vivo evidence and mechanistic understanding remain elusive. Preeclampsia is associated with impaired placental angiogenesis. We have recently shown that interleukin (IL)-10 can support trophoblast-driven endovascular crosstalk. Accordingly, we hypothesize that pathological levels of oxygen coupled with IL-10 deficiency induce severe preeclampsia-like features coupled with elevated production of antiangiogenic factors, apoptotic pathways, and placental injury. Exposure of pregnant wild-type and IL-10(-/-) mice to 9.5% oxygen resulted in graded placental injury and systemic symptoms of renal pathology, proteinuria (wild-type 645.15 ± 115.73 versus 198.09 ± 93.45; IL-10(-/-) 819.31 ± 127.85 versus 221.45 ± 82.73 μg/mg/24 hours) and hypertension (wild-type 118.37 ± 14.45 versus 78.67 ± 14.07; IL-10(-/-) 136.03 ± 22.59 versus 83.97 ± 18.25 mm Hg). Recombinant IL-10 reversed hypoxia-induced features in pregnant IL-10(-/-) mice confirming the protective role of IL-10 in preeclampsia. Hypoxic exposure caused marked elevation of soluble fms-like tyrosine kinase 1 (110.8 ± 20.1 versus 44.7 ± 11.9 ng/mL) in IL-10(-/-) mice compared with their wild-type counterparts (81.6 ± 13.1 versus 41.2 ± 8.9 ng/mL), whereas soluble endoglin was induced to similar levels in both strains (approximately 380 ± 50 versus 180 ± 31 ng/mL). Hypoxia-induced elevation of p53 was associated with marked induction of proapoptotic protein Bax, downregulation of Bcl-2, and trophoblast-specific apoptosis in utero-placental tissue. Collectively, we conclude that severe preeclampsia pathology could be triggered under certain threshold oxygen levels coupled with intrinsic IL-10 deficiency, which lead to excessive activation of antiangiogenic and apoptotic pathways.

  16. Changes in reactive oxygen species, superoxide dismutase, and hypoxia-inducible factor-1α levels in missed abortion.

    Science.gov (United States)

    Zhu, Li-Jun; Chen, Ya-Ping; Chen, Bing-Jin; Mei, Xiao-Hui

    2014-01-01

    This study aimed to investigate changes in the expression levels of reactive oxygen species (ROS), superoxide dismutase (SOD), and hypoxia-inducible factor-1α (HIF-1α) in the trophoblasts of patients who had experienced missed abortions. The missed abortion group included 28 patients with missed abortions. The control group was comprised of 35 women who had elected to undergo surgically induced abortion in their first trimester, and whose embryos were confirmed to be alive before surgery. No woman in either group had any known causative factor for missed or spontaneous abortion. As soon as the diagnosis of "missed abortion" was definitively made, the chorionic trophoblast was obtained by induced abortion operation. The same method was used for individuals in the control group, who were at 7-10 weeks of pregnancy. Levels of ROS, SOD, and HIF-1α in the chorionic trophoblasts from women in both groups were examined within 1 hour by fluorescent staining, chemiluminometry, and enzyme immunoassay methods. The SOD and HIF-1α levels were lower and the ROS level was higher in the trophoblasts from women in the missed abortion group compared to levels in the control group (P abortion are altered compared to levels in control patients. Changes in these factors should be evaluated further for their potential role in missed abortion.

  17. Decreased extracellular adenosine levels lead to loss of hypoxia-induced neuroprotection after repeated episodes of exposure to hypoxia.

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    Mei Cui

    Full Text Available Achieving a prolonged neuroprotective state following transient ischemic attacks (TIAs is likely to effectively reduce the brain damage and neurological dysfunction associated with recurrent stroke. HPC is a phenomenon in which advanced exposure to mild hypoxia reduces the stroke volume produced by a subsequent TIA. However, this neuroprotection is not long-lasting, with the effects reaching a peak after 3 days. Therefore, in this study, we investigated the use of multiple episodes of hypoxic exposure at different time intervals to induce longer-term protection in a mouse stroke model. C57BL/6 mice were subjected to different hypoxic preconditioning protocols: a single episode of HPC or five identical episodes at intervals of 3 days (E3d HPC or 6 days (E6d HPC. Three days after the last hypoxic exposure, temporary middle cerebral artery occlusion (MCAO was induced. The effects of these HPC protocols on hypoxia-inducible factor (HIF regulated gene mRNA expression were measured by quantitative PCR. Changes in extracellular adenosine concentrations, known to exert neuroprotective effects, were also measured using in vivo microdialysis and high pressure liquid chromatography (HPLC. Neuroprotection was provided by E6d HPC but not E3d HPC. HIF-regulated target gene expression increased significantly following all HPC protocols. However, E3d HPC significantly decreased extracellular adenosine and reduced cerebral blood flow in the ischemic region with upregulated expression of the adenosine transporter, equilibrative nucleoside transporter 1 (ENT1. An ENT1 inhibitor, propentofylline increased the cerebral blood flow and re-established neuroprotection in E3d HPC. Adenosine receptor specific antagonists showed that adenosine mainly through A1 receptor mediates HPC induced neuroprotection. Our data indicate that cooperation of HIF-regulated genes and extracellular adenosine is necessary for HPC-induced neuroprotection.

  18. Apelin Protects Primary Rat Retinal Pericytes from Chemical Hypoxia-Induced Apoptosis

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    Li Chen

    2015-01-01

    Full Text Available Pericytes are a population of cells that participate in normal vessel architecture and regulate permeability. Apelin, as the endogenous ligand of G protein-coupled receptor APJ, participates in a number of physiological and pathological processes. To date, the effect of apelin on pericyte is not clear. Our study aimed to investigate the potential protection mechanisms of apelin, with regard to primary rat retinal pericytes under hypoxia. Immunofluorescence staining revealed that pericytes colocalized with APJ in the fibrovascular membranes dissected from proliferative diabetic retinopathy patients. In the in vitro studies, we first demonstrated that the expression of apelin/APJ was upregulated in pericytes under hypoxia, and apelin increased pericytes proliferation and migration. Moreover, knockdown of apelin in pericyte was achieved via lentivirus-mediated RNA interference. After the inhibition of apelin, pericytes proliferation was inhibited significantly in hypoxia culture condition. Furthermore, exogenous recombinant apelin effectively prevented hypoxia-induced apoptosis through downregulating active-caspase 3 expression and increasing the ratio of B cell lymphoma-2 (Bcl-2/Bcl-2 associated X protein (Bax in pericytes. These results suggest that apelin suppressed hypoxia-induced pericytes injury, which indicated that apelin could be a potential therapeutic target for retinal angiogenic diseases.

  19. Hypoxia Inducible Factor (HIF Hydroxylases as Regulators of Intestinal Epithelial Barrier FunctionSummary

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    Mario C. Manresa

    2017-05-01

    Full Text Available Human health is dependent on the ability of the body to extract nutrients, fluids, and oxygen from the external environment while at the same time maintaining a state of internal sterility. Therefore, the cell layers that cover the surface areas of the body such as the lung, skin, and gastrointestinal mucosa provide vital semipermeable barriers that allow the transport of essential nutrients, fluid, and waste products, while at the same time keeping the internal compartments free of microbial organisms. These epithelial surfaces are highly specialized and differ in their anatomic structure depending on their location to provide appropriate and effective site-specific barrier function. Given this important role, it is not surprising that significant disease often is associated with alterations in epithelial barrier function. Examples of such diseases include inflammatory bowel disease, chronic obstructive pulmonary disease, and atopic dermatitis. These chronic inflammatory disorders often are characterized by diminished tissue oxygen levels (hypoxia. Hypoxia triggers an adaptive transcriptional response governed by hypoxia-inducible factors (HIFs, which are repressed by a family of oxygen-sensing HIF hydroxylases. Here, we review recent evidence suggesting that pharmacologic hydroxylase inhibition may be of therapeutic benefit in inflammatory bowel disease through the promotion of intestinal epithelial barrier function through both HIF-dependent and HIF-independent mechanisms. Keywords: Epithelial Barrier, Inflammatory Bowel Disease, Hypoxia, Hypoxia-Inducible Factor (HIF Hydroxylases

  20. Role of Hypoxia-Induced Brain Derived Neurotrophic Factor in Human Pulmonary Artery Smooth Muscle.

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    William Hartman

    Full Text Available Hypoxia effects on pulmonary artery structure and function are key to diseases such as pulmonary hypertension. Recent studies suggest that growth factors called neurotrophins, particularly brain-derived neurotrophic factor (BDNF, can influence lung structure and function, and their role in the pulmonary artery warrants further investigation. In this study, we examined the effect of hypoxia on BDNF in humans, and the influence of hypoxia-enhanced BDNF expression and signaling in human pulmonary artery smooth muscle cells (PASMCs.48h of 1% hypoxia enhanced BDNF and TrkB expression, as well as release of BDNF. In arteries of patients with pulmonary hypertension, BDNF expression and release was higher at baseline. In isolated PASMCs, hypoxia-induced BDNF increased intracellular Ca2+ responses to serotonin: an effect altered by HIF1α inhibition or by neutralization of extracellular BDNF via chimeric TrkB-Fc. Enhanced BDNF/TrkB signaling increased PASMC survival and proliferation, and decreased apoptosis following hypoxia.Enhanced expression and signaling of the BDNF-TrkB system in PASMCs is a potential mechanism by which hypoxia can promote changes in pulmonary artery structure and function. Accordingly, the BDNF-TrkB system could be a key player in the pathogenesis of hypoxia-induced pulmonary vascular diseases, and thus a potential target for therapy.

  1. Senp1 drives hypoxia-induced polycythemia via GATA1 and Bcl-xL in subjects with Monge's disease.

    Science.gov (United States)

    Azad, Priti; Zhao, Huiwen W; Cabrales, Pedro J; Ronen, Roy; Zhou, Dan; Poulsen, Orit; Appenzeller, Otto; Hsiao, Yu Hsin; Bafna, Vineet; Haddad, Gabriel G

    2016-11-14

    In this study, because excessive polycythemia is a predominant trait in some high-altitude dwellers (chronic mountain sickness [CMS] or Monge's disease) but not others living at the same altitude in the Andes, we took advantage of this human experiment of nature and used a combination of induced pluripotent stem cell technology, genomics, and molecular biology in this unique population to understand the molecular basis for hypoxia-induced excessive polycythemia. As compared with sea-level controls and non-CMS subjects who responded to hypoxia by increasing their RBCs modestly or not at all, respectively, CMS cells increased theirs remarkably (up to 60-fold). Although there was a switch from fetal to adult HgbA0 in all populations and a concomitant shift in oxygen binding, we found that CMS cells matured faster and had a higher efficiency and proliferative potential than non-CMS cells. We also established that SENP1 plays a critical role in the differential erythropoietic response of CMS and non-CMS subjects: we can convert the CMS phenotype into that of non-CMS and vice versa by altering SENP1 levels. We also demonstrated that GATA1 is an essential downstream target of SENP1 and that the differential expression and response of GATA1 and Bcl-xL are a key mechanism underlying CMS pathology. © 2016 Azad et al.

  2. Metabolic profiling reveals potential metabolic markers associated with Hypoxia Inducible Factor-mediated signalling in hypoxic cancer cells.

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    Armitage, Emily G; Kotze, Helen L; Allwood, J William; Dunn, Warwick B; Goodacre, Royston; Williams, Kaye J

    2015-10-28

    Hypoxia inducible factors (HIFs) plays an important role in oxygen compromised environments and therefore in tumour survival. In this research, metabolomics has been applied to study HIFs metabolic function in two cell models: mouse hepatocellular carcinoma and human colon carcinoma, whereby the metabolism has been profiled for a range of oxygen potentials. Wild type cells have been compared to cells deficient in HIF signalling to reveal its effect on cellular metabolism under normal oxygen conditions as well as low oxygen, hypoxic and anoxic environments. Characteristic responses to hypoxia that were conserved across both cell models involved the anti-correlation between 2-hydroxyglutarate, 2-oxoglutarate, fructose, hexadecanoic acid, hypotaurine, pyruvate and octadecenoic acid with 4-hydroxyproline, aspartate, cysteine, glutamine, lysine, malate and pyroglutamate. Further to this, network-based correlation analysis revealed HIF specific pathway responses to each oxygen condition that were also conserved between cell models. From this, 4-hydroxyproline was revealed as a regulating hub in low oxygen survival of WT cells while fructose appeared to be in HIF deficient cells. Pathways surrounding these hubs were built from the direct connections of correlated metabolites that look beyond traditional pathways in order to understand the mechanism of HIF response to low oxygen environments.

  3. Augmentation of leptin and hypoxia-inducible factor 1alpha mRNAs in the pre-eclamptic placenta.

    Science.gov (United States)

    Iwagaki, S; Yokoyama, Y; Tang, L; Takahashi, Y; Nakagawa, Y; Tamaya, T

    2004-05-01

    The placenta is a major source of leptin in the fetomaternal circulation, although its physiological role remains to be clarified. Leptin in the fetomaternal circulation is proposed to be a marker of acute stress in the fetus, and the fetus suffering from pre-eclampsia would be under chronic stress. In 16 pre-eclamptic placentas, the expressions of leptin, hypoxia-inducible factor 1alpha (HIF1alpha) and leptin receptor mRNAs were analyzed by semi-quantitative reverse-transcriptase-polymerase chain reaction and compared with clinical data. The co-expressions of leptin and the isoforms of the leptin receptor were observed in all the pre-eclamptic placentas. Leptin mRNA was significantly augmented in the pre-eclamptic placentas, although the level in fetal plasma was not high. The level of the expression of leptin mRNA was correlated with the placental HIF1alpha mRNA level and fetal body weight, but not with the levels of the leptin receptor isoforms in the pre-eclamptic placentas. This observation may suggest that autocrine/paracrine regulation of leptin exists in the human placenta and is upregulated in the pre-eclamptic placenta.

  4. Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors: A Potential New Treatment for Anemia in Patients With CKD.

    Science.gov (United States)

    Gupta, Nupur; Wish, Jay B

    2017-06-01

    Erythropoiesis-stimulating agents (ESAs) increase hemoglobin levels, reduce transfusion requirements, and have been the standard of treatment for anemia in patients with chronic kidney disease (CKD) since 1989. Many safety concerns have emerged regarding the use of ESAs, including an increased occurrence of cardiovascular events and vascular access thrombosis. Hypoxia-inducible factor (HIF) prolyl hydroxylase (PH) enzyme inhibitors are a new class of agents for the treatment of anemia in CKD. These agents work by stabilizing the HIF complex and stimulating endogenous erythropoietin production even in patients with end-stage kidney disease. HIF-PH inhibitors improve iron mobilization to the bone marrow. They are administered orally, which may be a more favorable route for patients not undergoing hemodialysis. By inducing considerably lower but more consistent blood erythropoietin levels than ESAs, HIF-PH inhibitors may be associated with fewer adverse cardiovascular effects at comparable hemoglobin levels, although this has yet to be proved in long-term clinical trials. One significant concern regarding the long-term use of these agents is their possible effect on tumor growth. There are 4 such agents undergoing phase 2 and 3 clinical trials in the United States; this report provides a focused review of HIF-PH inhibitors and their potential clinical utility in the management of anemia of CKD. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Induction of erythropoiesis by hypoxia-inducible factor prolyl hydroxylase inhibitors without promotion of tumor initiation, progression, or metastasis in a VEGF-sensitive model of spontaneous breast cancer

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    Seeley TW

    2017-03-01

    Full Text Available Todd W Seeley, Mark D Sternlicht, Stephen J Klaus, Thomas B Neff, David Y Liu Therapeutics R&D, FibroGen, Inc., San Francisco, CA, USA Abstract: The effects of pharmacological hypoxia-inducible factor (HIF stabilization were investigated in the MMTV-Neundl-YD5 (NeuYD mouse model of breast cancer. This study first confirmed the sensitivity of this model to increased vascular endothelial growth factor (VEGF, using bigenic NeuYD;MMTV-VEGF-25 mice. Tumor initiation was dramatically accelerated in bigenic animals. Bigenic tumors were also more aggressive, with shortened doubling times and increased lung metastasis as compared to NeuYD controls. In separate studies, NeuYD mice were treated three times weekly from 7 weeks of age until study end with two different HIF prolyl hydroxylase inhibitors (HIF-PHIs, FG-4497 or roxadustat (FG-4592. In NeuYD mice, HIF-PHI treatments elevated erythropoiesis markers, but no differences were detected in tumor onset or the phenotypes of established tumors. Keywords: cancer progression, erythropoiesis, hypoxia-inducible factor, hypoxia-inducible factor prolyl hydroxylase inhibitors, vascular endothelial growth factor, MMTV-Neu breast cancer model

  6. Reversion of lethality and growth defects in Fatiga oxygen-sensor mutant flies by loss of hypoxia-inducible factor-alpha/Sima.

    Science.gov (United States)

    Centanin, Lázaro; Ratcliffe, Peter J; Wappner, Pablo

    2005-11-01

    Hypoxia-Inducible Factor (HIF) prolyl hydroxylase domains (PHDs) have been proposed to act as sensors that have an important role in oxygen homeostasis. In the presence of oxygen, they hydroxylate two specific prolyl residues in HIF-alpha polypeptides, thereby promoting their proteasomal degradation. So far, however, the developmental consequences of the inactivation of PHDs in higher metazoans have not been reported. Here, we describe novel loss-of-function mutants of fatiga, the gene encoding the Drosophila PHD oxygen sensor, which manifest growth defects and lethality. We also report a null mutation in dHIF-alpha/sima, which is unable to adapt to hypoxia but is fully viable in normoxic conditions. Strikingly, loss-of-function mutations of sima rescued the developmental defects observed in fatiga mutants and enabled survival to adulthood. These results indicate that the main functions of Fatiga in development, including control of cell size, involve the regulation of dHIF/Sima.

  7. Reversion of lethality and growth defects in Fatiga oxygen-sensor mutant flies by loss of Hypoxia-Inducible Factor-α/Sima

    Science.gov (United States)

    Centanin, Lázaro; Ratcliffe, Peter J; Wappner, Pablo

    2005-01-01

    Hypoxia-Inducible Factor (HIF) prolyl hydroxylase domains (PHDs) have been proposed to act as sensors that have an important role in oxygen homeostasis. In the presence of oxygen, they hydroxylate two specific prolyl residues in HIF-α polypeptides, thereby promoting their proteasomal degradation. So far, however, the developmental consequences of the inactivation of PHDs in higher metazoans have not been reported. Here, we describe novel loss-of-function mutants of fatiga, the gene encoding the Drosophila PHD oxygen sensor, which manifest growth defects and lethality. We also report a null mutation in dHIF-α/sima, which is unable to adapt to hypoxia but is fully viable in normoxic conditions. Strikingly, loss-of-function mutations of sima rescued the developmental defects observed in fatiga mutants and enabled survival to adulthood. These results indicate that the main functions of Fatiga in development, including control of cell size, involve the regulation of dHIF/Sima. PMID:16179946

  8. Zeaxanthin Inhibits Hypoxia-Induced VEGF Secretion by RPE Cells through Decreased Protein Levels of Hypoxia-Inducible Factors-1α

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    Richard Rosen

    2015-01-01

    Full Text Available Hypoxia is the most important stimulus leading to upregulation of VEGF in the retina and this is caused by accumulation of hypoxia-inducible factors-1α (HIF-1α protein. The effects of zeaxanthin, a natural phytochemical, on the VEGF and HIF-1α expression in the primary culture of human retinal pigment epithelial (RPE cells were studied. An in vitro RPE cell hypoxia model was established by placing cells under 1% oxygen pressure or by adding cobalt chloride (CoCl2 to the culture medium. RPE cells and conditioned media were collected from cultures treated with and without zeaxanthin under normoxic and hypoxic conditions. VEGF and HIF-1α protein and RNA levels were measured by ELISA kits and RT-PCR, respectively. Hypoxia caused a significant increase of VEGF expression and accumulation of HIF-1α in RPE cells. Zeaxanthin at 50–150 μM significantly inhibited the expression of VEGF and accumulation of HIF-1α protein caused by hypoxia but did not affect expression of VEGF and HIF-1α under normoxic conditions. This is the first report on the effect of zeaxanthin on VEGF and HIF-1α levels in cultured RPE cells and suggests that zeaxanthin may have potential value in the prevention and treatment of various retinal diseases associated with vascular leakage and neovascularization.

  9. Hypoxia-inducing factors as master regulators of stemness properties and altered metabolism of cancer- and metastasis-initiating cells

    Science.gov (United States)

    Mimeault, Murielle; Batra, Surinder K

    2013-01-01

    Accumulating lines of experimental evidence have revealed that hypoxia-inducible factors, HIF-1α and HIF-2α, are key regulators of the adaptation of cancer- and metastasis-initiating cells and their differentiated progenies to oxygen and nutrient deprivation during cancer progression under normoxic and hypoxic conditions. Particularly, the sustained stimulation of epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), stem cell factor (SCF) receptor KIT, transforming growth factor-β receptors (TGF-βRs) and Notch and their downstream signalling elements such as phosphatidylinositol 3′-kinase (PI3K)/Akt/molecular target of rapamycin (mTOR) may lead to an enhanced activity of HIFs. Moreover, the up-regulation of HIFs in cancer cells may also occur in the hypoxic intratumoral regions formed within primary and secondary neoplasms as well as in leukaemic cells and metastatic prostate and breast cancer cells homing in the hypoxic endosteal niche of bone marrow. The activated HIFs may induce the expression of numerous gene products such as induced pluripotency-associated transcription factors (Oct-3/4, Nanog and Sox-2), glycolysis- and epithelial-mesenchymal transition (EMT) programme-associated molecules, including CXC chemokine receptor 4 (CXCR4), snail and twist, microRNAs and angiogenic factors such as vascular endothelial growth factor (VEGF). These gene products in turn can play critical roles for high self-renewal ability, survival, altered energy metabolism, invasion and metastases of cancer cells, angiogenic switch and treatment resistance. Consequently, the targeting of HIF signalling network and altered metabolic pathways represents new promising strategies to eradicate the total mass of cancer cells and improve the efficacy of current therapies against aggressive and metastatic cancers and prevent disease relapse. PMID:23301832

  10. Cancer cell-associated cytoplasmic B7–H4 is induced by hypoxia through hypoxia-inducible factor-1α and promotes cancer cell proliferation

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    Jeon, You-Kyoung [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Park, Sae-Gwang; Choi, Il-Whan [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Lee, Soo-Woong [Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Lee, Sang Min [Department of Internal Medicine, Division of Hematology/Oncology, Busan Paik Hospital, Inje University, Busan 614-735 (Korea, Republic of); Choi, Inhak, E-mail: miccih@inje.ac.kr [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of)

    2015-04-03

    Aberrant B7–H4 expression in cancer tissues serves as a novel prognostic biomarker for poor survival in patients with cancer. However, the factor(s) that induce cancer cell-associated B7–H4 remain to be fully elucidated. We herein demonstrate that hypoxia upregulates B7–H4 transcription in primary CD138{sup +} multiple myeloma cells and cancer cell lines. In support of this finding, analysis of the Multiple Myeloma Genomics Portal (MMGP) data set revealed a positive correlation between the mRNA expression levels of B7–H4 and the endogenous hypoxia marker carbonic anhydrogenase 9. Hypoxia-induced B7–H4 expression was detected in the cytoplasm, but not in cancer cell membranes. Chromatin immunoprecipitation analysis demonstrated binding of hypoxia-inducible factor-1α (HIF-1α) to proximal hypoxia-response element (HRE) sites within the B7–H4 promoter. Knockdown of HIF-1α and pharmacological inhibition of HIF-1α diminished B7–H4 expression. Furthermore, knockdown of cytoplasmic B7–H4 in MCF-7 decreased the S-phase cell population under hypoxia. Finally, MMGP analysis revealed a positive correlation between the transcript levels of B7–H4 and proliferation-related genes including MKI67, CCNA1, and Myc in several patients with multiple myeloma. Our results provide insight into the mechanisms underlying B7–H4 upregulation and its role in cancer cell proliferation in a hypoxic tumor microenvironment. - Highlights: • Hypoxia upregulates B7–H4 transcription and protein expression. • Hypoxia-induced B7–H4 is detected in the cytoplasm, but not on membrane. • ChIP assay reveals a binding of HIF-1α to B7–H4 promoter at HRE site. • Knockdown and pharmacological inhibition of HIF-1α reduce B7–H4 expression. • B7–H4 knockdown decrease the number of cells in S-phase of cell cycle.

  11. Regulation of hypoxia-inducible factor-1α (HIF-1α expression by interleukin-1β (IL-1 β, insulin-like growth factors I (IGF-I and II (IGF-II in human osteoarthritic chondrocytes

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    Angelica Rossi Sartori-Cintra

    2012-01-01

    Full Text Available OBJECTIVE: Hypoxia-inducible factor 1 alpha regulates genes related to cellular survival under hypoxia. This factor is present in osteroarthritic chondrocytes, and cytokines, such as interleukin-1 beta, participate in the pathogenesis of osteoarthritis, thereby increasing the activities of proteolytic enzymes, such as matrix metalloproteinases, and accelerating cartilage destruction. We hypothesize that Hypoxia Inducible Factor-1 alpha (HIF-1α can regulate cytokines (catabolic action and/or growth factors (anabolic action in osteoarthritis. The purpose of this study was to investigate the modulation of HIF-1α in human osteoarthritic chondrocytes by interleukin-1 beta (IL-1β and insulin-like growth factors I (IGF-I and II (IGF-II and to determine the involvement of the phosphatidylinositol-3kinase (PI-3K pathway in this process. METHODS: Human osteroarthritic chondrocytes were stimulated with IL-1β, IGF-I and IGF-II and LY294002, a specific inhibitor of PI-3K. Nuclear protein levels and gene expression were analyzed by western blot and quantitative reverse transcription-polymerase chain reaction analyses, respectively. RESULTS: HIF-1α expression was upregulated by IL-1β at the protein level but not at the gene level. IGF-I treatment resulted in increases in both the protein and mRNA levels of HIF-1α , whereas IGF-II had no effect on its expression. However, all of these stimuli exploited the PI-3K pathway. CONCLUSION: IL-1β upregulated the levels of HIF-1α protein post-transcriptionally, whereas IGF-I increased HIF-1α at the transcript level. In contrast, IGF-II did not affect the protein or gene expression levels of HIF-1α . Furthermore, all of the tested stimuli exploited the PI-3K pathway to some degree. Based on these findings, we are able to suggest that Hypoxia inducible Factor-1 exhibits protective activity in chondrocytes during osteoarthritis.

  12. Expressions of hypoxia-inducible factor-1 and epithelial cell adhesion molecule are linked with aggressive local recurrence of hepatocellular carcinoma after radiofrequency ablation therapy.

    Science.gov (United States)

    Yamada, Shinichiro; Utsunomiya, Tohru; Morine, Yuji; Imura, Satoru; Ikemoto, Tetsuya; Arakawa, Yusue; Kanamoto, Mami; Iwahashi, Shuichi; Saito, Yu; Takasu, Chie; Ishikawa, Daichi; Shimada, Mitsuo

    2014-06-01

    Radiofrequency ablation (RFA) is a widely used therapy for hepatocellular carcinoma (HCC). Several reports have demonstrated the aggressive local recurrence of HCC after RFA, suggesting that induction of further malignant transformation of HCC has occurred. Eighty-eight (88) patients with HCC who underwent hepatic resection were included in this study. Hepatectomy was indicated for local recurrence of HCC after RFA (n = 10, RFA group) and for HCC without prior RFA (n = 78, non-RFA group). Clinicopathological data and the patient's prognosis after hepatectomy were compared between the two groups. Expression levels of hypoxia-inducible factor-1 (HIF-1), epithelial cell adhesion molecule (EpCAM), CD44, and vascular endothelial growth factor messenger RNA (mRNA) in the tumor tissues were also examined. The RFA group showed higher frequency of portal vein invasion and less tumor differentiation compared with the non-RFA group (p treatment by RFA.

  13. Sulforaphane inhibits hypoxia-induced HIF-1α and VEGF expression and migration of human colon cancer cells.

    Science.gov (United States)

    Kim, Dong Hwan; Sung, Bokyung; Kang, Yong Jung; Hwang, Seong Yeon; Kim, Min Jeong; Yoon, Jeong-Hyun; Im, Eunok; Kim, Nam Deuk

    2015-12-01

    The effects of sulforaphane (a natural product commonly found in broccoli) was investigated on hypoxia inducible factor-1α (HIF-1α) expression in HCT116 human colon cancer cells and AGS human gastric cancer cells. We found that hypoxia-induced HIF-1α protein expression in HCT116 and AGS cells, while treatment with sulforaphane markedly and concentration-dependently inhibited HIF-1α expression in both cell lines. Treatment with sulforaphane inhibited hypoxia-induced vascular endothelial growth factor (VEGF) expression in HCT116 cells. Treatment with sulforaphane modulated the effect of hypoxia on HIF-1α stability. However, degradation of HIF-1α by sulforaphane was not mediated through the 26S proteasome pathway. We also found that the inhibition of HIF-1α by sulforaphane was not mediated through AKT and extracellular signal-regulated kinase phosphorylation under hypoxic conditions. Finally, hypoxia-induced HCT116 cell migration was inhibited by sulforaphane. These data suggest that sulforaphane may inhibit human colon cancer progression and cancer cell angiogenesis by inhibiting HIF-1α and VEGF expression. Taken together, these results indicate that sulforaphane is a new and potent chemopreventive drug candidate for treating patients with human colon cancer.

  14. Expression of hypoxia-inducible factor 1 alpha and its downstream targets in fibroepithelial tumors of the breast

    NARCIS (Netherlands)

    Kuijper, Arno; Groep, P. van der; Wall, E. van der; Diest, P.J. van

    2005-01-01

    INTRODUCTION Hypoxia-inducible factor 1 (HIF-1) alpha and its downstream targets carbonic anhydrase IX (CAIX) and vascular endothelial growth factor (VEGF) are key factors in the survival of proliferating tumor cells in a hypoxic microenvironment. We studied the expression and prognostic relevance

  15. Hypoxia, hypoxia-inducible transcription factor, and macrophages in human atherosclerotic plaques are correlated with intraplaque angiogenesis

    NARCIS (Netherlands)

    Sluimer, Judith C.; Gasc, Jean-Marie; van Wanroij, Job L.; Kisters, Natasja; Groeneweg, Mathijs; Sollewijn Gelpke, Maarten D.; Cleutjens, Jack P.; van den Akker, Luc H.; Corvol, Pierre; Wouters, Bradly G.; Daemen, Mat J.; Bijnens, Ann-Pascale J.

    2008-01-01

    We sought to examine the presence of hypoxia in human carotid atherosclerosis and its association with hypoxia-inducible transcription factor (HIF) and intraplaque angiogenesis. Atherosclerotic plaques develop intraplaque angiogenesis, which is a typical feature of hypoxic tissue and expression of

  16. Hypoxia Inducible Factor 3α Plays a Critical Role in Alveolarization and Distal Epithelial Cell Differentiation during Mouse Lung Development

    NARCIS (Netherlands)

    Y. Huang (Yao); J.K. Ochieng (Joshua); M. van Kempen (Marjon); A. Boerema-de Munck (Anne); S.M.A. Swagemakers (Sigrid); W.F.J. van IJcken (Wilfred); F.G. Grosveld (Frank); D. Tibboel (Dick); R.J. Rottier (Robbert)

    2013-01-01

    textabstractLung development occurs under relative hypoxia and the most important oxygen-sensitive response pathway is driven by Hypoxia Inducible Factors (HIF). HIFs are heterodimeric transcription factors of an oxygen-sensitive subunit, HIFα, and a constitutively expressed subunit, HIF1β. HIF1α

  17. TCDD Induces the Hypoxia-Inducible Factor (HIF-1α Regulatory Pathway in Human Trophoblastic JAR Cells

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    Tien-Ling Liao

    2014-09-01

    Full Text Available The exposure to dioxin can compromise pregnancy outcomes and increase the risk of preterm births. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD has been demonstrated to induce placental hypoxia at the end of pregnancy in a rat model, and hypoxia has been suggested to be the cause of abnormal trophoblast differentiation and placental insufficiency syndromes. In this study, we demonstrate that the non-hypoxic stimulation of human trophoblastic cells by TCDD strongly increased hypoxia inducible factor-1 alpha (HIF-1α stabilization. TCDD exposure induced the generation of reactive oxygen species (ROS and nitric oxide. TCDD-induced HIF-1α stabilization and Akt phosphorylation was inhibited by pretreatment with wortmannin (a phosphatidylinositol 3-kinase (PI3K inhibitor or N-acetylcysteine (a ROS scavenger. The augmented HIF-1α stabilization by TCDD occurred via the ROS-dependent activation of the PI3K/Akt pathway. Additionally, a significant increase in invasion and metallomatrix protease-9 activity was found in TCDD-treated cells. The gene expression of vascular endothelial growth factor and placental growth factor was induced upon TCDD stimulation, whereas the protein levels of peroxisome proliferator-activated receptor γ (PPARγ, PPARγ coactivator-1α, mitochondrial transcription factor, and uncoupling protein 2 were decreased. Our results indicate that an activated HIF-1α pathway, elicited oxidative stress, and induced metabolic stress contribute to TCDD-induced trophoblastic toxicity. These findings may provide molecular insight into the TCDD-induced impairment of trophoblast function and placental development.

  18. Sphingosine-1-Phosphate as a Regulator of Hypoxia-Induced Factor-1α in Thyroid Follicular Carcinoma Cells.

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    Veronica Kalhori

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive lipid, which regulates several cancer-related processes including migration and angiogenesis. We have previously shown S1P to induce migration of follicular ML-1 thyroid cancer cells. Hypoxia-induced factor-1 (HIF-1 is an oxygen-sensitive transcription factor, which adapts cells to hypoxic conditions through increased survival, motility and angiogenesis. Due to these properties and its increased expression in response to intratumoral hypoxia, HIF-1 is considered a significant regulator of tumor biology. We found S1P to increase expression of the regulatory HIF-1α subunit in normoxic ML-1 cells. S1P also increased HIF-1 activity and expression of HIF-1 target genes. Importantly, inhibition or knockdown of HIF-1α attenuated the S1P-induced migration of ML-1 cells. S1P-induced HIF-1α expression was mediated by S1P receptor 3 (S1P3, Gi proteins and their downstream effectors MEK, PI3K, mTOR and PKCβI. Half-life measurements with cycloheximide indicated that S1P treatment stabilized the HIF-1α protein. On the other hand, S1P activated translational regulators eIF-4E and p70S6K, which are known to control HIF-1α synthesis. In conclusion, we have identified S1P as a non-hypoxic regulator of HIF-1 activity in thyroid cancer cells, studied the signaling involved in S1P-induced HIF-1α expression and shown S1P-induced migration to be mediated by HIF-1.

  19. Nuclear expression of hypoxia-inducible factor-1alpha in clear cell renal cell carcinoma is involved in tumor progression.

    Science.gov (United States)

    Di Cristofano, Claudio; Minervini, Andrea; Menicagli, Michele; Salinitri, Giuseppe; Bertacca, Gloria; Pefanis, Gerasimos; Masieri, Lorenzo; Lessi, Francesca; Collecchi, Paola; Minervini, Riccardo; Carini, Marco; Bevilacqua, Generoso; Cavazzana, Andrea

    2007-12-01

    The most frequent genomic abnormality in clear cell renal cell carcinoma (cc-RCC) is inactivation of Von Hippel-Lindau gene (VHL). pVHL19 is a ligase promoting proteosomal degradation of hypoxia-inducible factor-1alpha (HIF-1alpha); pVHL30 is associated with microtubules. VHL exert its oncogenetic action both directly and through HIF-1alpha activation. TNM classification is unable to define a correct prognostic evaluation of intracapsular cc-RCC. The nucleo-cytoplasmic trafficking in VHL/HIF-1alpha pathway could be relevant in understanding the molecular pathogenesis of renal carcinogenesis. This study analyzes VHL/HIF-1alpha proteins in a large series of intracapsular cc-RCCs, correlating their expression and cellular localization with prognosis. Two anti-pVHL (clones Ig32 and Ig33) and 1 anti-HIF-1alpha were used on tissue microarrays from 136 intracapsular cc-RCCs (mean follow-up: 74 mo). Clone 32 recognizes both pVHLs, whereas clone 33 only pVHL30. Results were matched with clinicopathologic variables and tumor-specific survival (TSS). A strong cytoplasmic positivity was found for all antibodies in the largest part of cases, associated to a strong nuclear localization in the case of HIF-1alpha. All pVHL-negative cases were associated with high HIF-1alpha expression. pVHL negativity and HIF-1alpha nuclear positivity significantly correlated with shorter TSS. In multivariate analysis both pVHL negativity and HIF-1alpha nuclear expression were independent predictors of TSS. The localization of the proteins well matches with their role and with the supposed tumor molecular pathways. The correlation with prognosis of VHL/HIF-1alpha alterations confirms the relevance of their molecular pathway and of the cellular trafficking of their products in the pathogenesis of renal cancer.

  20. Evidence for a lack of a direct transcriptional suppression of the iron regulatory peptide hepcidin by hypoxia-inducible factors.

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    Melanie Volke

    2009-11-01

    Full Text Available Hepcidin is a major regulator of iron metabolism and plays a key role in anemia of chronic disease, reducing intestinal iron uptake and release from body iron stores. Hypoxia and chemical stabilizers of the hypoxia-inducible transcription factor (HIF have been shown to suppress hepcidin expression. We therefore investigated the role of HIF in hepcidin regulation.Hepcidin mRNA was down-regulated in hepatoma cells by chemical HIF stabilizers and iron chelators, respectively. In contrast, the response to hypoxia was variable. The decrease in hepcidin mRNA was not reversed by HIF-1alpha or HIF-2alpha knock-down or by depletion of the HIF and iron regulatory protein (IRP target transferrin receptor 1 (TfR1. However, the response of hepcidin to hypoxia and chemical HIF inducers paralleled the regulation of transferrin receptor 2 (TfR2, one of the genes critical to hepcidin expression. Hepcidin expression was also markedly and rapidly decreased by serum deprivation, independent of transferrin-bound iron, and by the phosphatidylinositol 3 (PI3 kinase inhibitor LY294002, indicating that growth factors are required for hepcidin expression in vitro. Hepcidin promoter constructs mirrored the response of mRNA levels to interleukin-6 and bone morphogenetic proteins, but not consistently to hypoxia or HIF stabilizers, and deletion of the putative HIF binding motifs did not alter the response to different hypoxic stimuli. In mice exposed to carbon monoxide, hypoxia or the chemical HIF inducer N-oxalylglycine, liver hepcidin 1 mRNA was elevated rather than decreased.Taken together, these data indicate that hepcidin is neither a direct target of HIF, nor indirectly regulated by HIF through induction of TfR1 expression. Hepcidin mRNA expression in vitro is highly sensitive to the presence of serum factors and PI3 kinase inhibition and parallels TfR2 expression.

  1. Intermediary metabolite precursor dimethyl-2-ketoglutarate stabilizes hypoxia-inducible factor-1α by inhibiting prolyl-4-hydroxylase PHD2.

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    Peifeng Hou

    Full Text Available Hypoxia-inducible factor 1α (HIF-1α, a major mediator of tumor physiology, is activated during tumor progression, and its abundance is correlated with therapeutic resistance in a broad range of solid tumors. The accumulation of HIF-1α is mainly caused by hypoxia or through the mutated succinate dehydrogenase A (SDHA or fumarate hydratase (FH expression to inhibit its degradation. However, its activation under normoxic conditions, termed pseudohypoxia, in cells without mutated SDHA or FH is not well documented. Here, we show that dimethyl-2-ketoglutarate (DKG, a cell membrane-permeable precursor of a key metabolic intermediate, α-ketoglutarate (α-KG, known for its ability to rescue glutamine deficiency, transiently stabilized HIF-1α by inhibiting activity of the HIF prolyl hydroxylase domain-containing protein, PHD2. Consequently, prolonged DKG-treatment under normoxia elevated HIF-1α abundance and up-regulated the expression of its downstream target genes, thereby inducing a pseudohypoxic condition. This HIF-1α stabilization phenotype is similar to that from treatment of cells with desferrioxamine (DFO, an iron chelator, or dimethyloxalyglycine (DMOG, an established PHD inhibitor, but was not recapitulated with other α-KG analogues, such as Octyl-2KG, MPTOM001 and MPTOM002. Our study is the first example of an α-KG precursor to increase HIF-1α abundance and activity. We propose that DKG acts as a potent HIF-1α activator, highlighting the potential use of DKG to investigate the contribution of PHD2-HIF-1α pathway to tumor biology.

  2. Hypoxia-inducible factor-1α: a promising therapeutic target for autoimmune diseases.

    Science.gov (United States)

    Guan, Shi-Yang; Leng, Rui-Xue; Tao, Jin-Hui; Li, Xiang-Pei; Ye, Dong-Qing; Olsen, Nancy; Zheng, Song Guo; Pan, Hai-Feng

    2017-07-01

    Hypoxia-inducible factor-1α (HIF-1α) plays a crucial role in both innate and adaptive immunity. Emerging evidence indicates that HIF-1α is associated with the inflammation and pathologic activities of autoimmune diseases. Areas covered: Considering that the types of autoimmune diseases are complicated and various, this review aims to cover the typical kinds of autoimmune diseases, discuss the molecular mechanisms, biological functions and expression of HIF-1α in these diseases, and further explore its therapeutic potential. Expert opinion: Inflammation and hypoxia are interdependent. HIF-1α as a key regulator of hypoxia, exerts a crucial role in the balance between Th17 and Treg, and involves in the inflammation and pathologic activities of autoimmune diseases. Although there are many challenges remaining to be overcome, targeting HIF-1α could be a promising strategy for autoimmune diseases therapies.

  3. Effect of Ruscus extract and hesperidin methylchalcone on hypoxia-induced activation of endothelial cells.

    Science.gov (United States)

    Bouaziz, N; Michiels, C; Janssens, D; Berna, N; Eliaers, F; Panconi, E; Remacle, J

    1999-12-01

    Ruscus aculeatus extract and the flavonoid hesperidin methylchalcone (HMC) are drugs used in the treatment of chronic venous insufficiency. In the present study, we investigated their effects on the activation of endothelial cells by hypoxia, a condition which mimics venous blood stasis. We observed that Ruscus extract was able to inhibit the activation of endothelial cells by hypoxia: the decrease in ATP content, the activation of phospholipase A2 as well as the subsequent increase in neutrophil adherence with a maximal protection obtained at 50 microg/ml. HMC was also able to inhibit the hypoxia-induced decrease in ATP content. Furthermore, the effects of Ruscus extract and of HMC on this decrease seem to be additive. The biochemical mechanism evidenced in this work might explain some of the beneficial therapeutic effects of these products in the treatment of chronic venous insufficiency patients.

  4. The role of hypoxia-inducible factor-2 in digestive system cancers.

    Science.gov (United States)

    Zhao, J; Du, F; Shen, G; Zheng, F; Xu, B

    2015-01-15

    Hypoxia is an all but ubiquitous phenomenon in cancers. Two known hypoxia-inducible factors (HIFs), HIF-1α and HIF-2α, primarily mediate the transcriptional response to hypoxia. Despite the high homology between HIF-1α and HIF-2α, emerging evidence suggests differences between both molecules in terms of transcriptional targets as well as impact on multiple physiological pathways and tumorigenesis. To date, much progress has been made toward understanding the roles of HIF-2α in digestive system cancers. Indeed, HIF-2α has been shown to regulate multiple aspects of digestive system cancers, including cell proliferation, angiogenesis and apoptosis, metabolism, metastasis and resistance to chemotherapy. These findings make HIF-2α a critical regulator of this malignant phenotype. Here we summarize the function of HIF-2 during cancer development as well as its contribution to tumorigenesis in digestive system malignancies.

  5. Recent Advances in Developing Inhibitors for Hypoxia-Inducible Factor Prolyl Hydroxylases and Their Therapeutic Implications

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    So Yeon Kim

    2015-11-01

    Full Text Available Hypoxia-inducible factor (HIF prolyl hydroxylases (PHDs are members of the 2-oxoglutarate dependent non-heme iron dioxygenases. Due to their physiological roles in regulation of HIF-1α stability, many efforts have been focused on searching for selective PHD inhibitors to control HIF-1α levels for therapeutic applications. In this review, we first describe the structure of PHD2 as a molecular basis for structure-based drug design (SBDD and various experimental methods developed for measuring PHD activity. We further discuss the current status of the development of PHD inhibitors enabled by combining SBDD approaches with high-throughput screening. Finally, we highlight the clinical implications of small molecule PHD inhibitors.

  6. Sirtuin 6 Modulates Hypoxia-induced Apoptosis in Osteoblasts via Inhibition of Glycolysis: Implication for Pathogenesis of Periapical Lesions.

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    Kok, Sang-Heng; Hou, Kuo-Liang; Hong, Chi-Yuan; Chao, Ling-Hsiu; Hsiang-Hua Lai, Eddie; Wang, Han-Wei; Yang, Hsiang; Shun, Chia-Tung; Wang, Juo-Song; Lin, Sze-Kwan

    2015-10-01

    Osteoblast apoptosis is important in the regulation of inflammatory bone resorption. Hypoxia resulting from inflammation enhances glycolysis and apoptosis. Sirtuin 6 (SIRT6) is a modulator of glucose metabolism and apoptosis. In the study we assessed the role of SIRT6 in hypoxia-induced glycolysis and apoptosis in osteoblasts, with special attention on the significance of these cellular processes in periapical lesions. Human bone marrow-derived osteoblasts were cultured under hypoxia. Expression of lactate dehydrogenase A was examined by Western blot, and production of lactate was measured by colorimetric assay. Cleavage of poly (adenosine diphosphate ribose) polymerase was used as an apoptosis marker and assessed by Western blot. SIRT6 was overexpressed in osteoblasts by lentiviral gene transduction, and then glycolytic and apoptotic responses were studied. In a rat model of bacteria-induced periapical lesions, expressions of SIRT6 and markers of glycolysis and apoptosis in osteoblasts were examined. Hypoxia enhanced lactate dehydrogenase A expression and lactate production in osteoblasts. Poly (adenosine diphosphate ribose) polymerase cleavage was induced by hypoxia or lactate treatment. SIRT6 suppressed hypoxia-augmented glycolysis and inhibited apoptosis induced by hypoxia or lactate treatment. Expression of SIRT6 in osteoblasts was downregulated by hypoxia and inflammatory mediators. Development of periapical lesions in rats was associated with decreased expression of SIRT6 and increased glycolysis and apoptosis in osteoblasts. Our study suggested that hypoxia-induced apoptosis of osteoblasts is dependent on glycolytic activity. SIRT6 is a negative regulator of inflammation and may alleviate periapical lesions by suppressing osteoblastic glycolysis and apoptosis. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. Hypoxia-inducible factor 2α (HIF-2α) promotes colon cancer growth by potentiating Yes-associated protein 1 (YAP1) activity.

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    Ma, Xiaoya; Zhang, Huabing; Xue, Xiang; Shah, Yatrik M

    2017-10-13

    Colorectal cancer (CRC) is the third-leading cause of cancer mortality in the United States and other industrialized countries. A hypoxic microenvironment is a hallmark for solid tumors. The hypoxia-induced signal transduction is transcriptionally mediated by hypoxia-inducible factor (HIF). Three major HIF isoforms, HIF-1α, HIF-2α, and HIF-3α, are present in the intestine. Our previous work demonstrates that HIF-2α is essential for CRC growth and progression. However, the mechanisms mediating cell proliferation after hypoxia or HIF-2α activation in CRC are unclear. Data mining of RNA-Seq experiments with mouse models of intestinal HIF-2α or Yes-associated protein 1 (YAP1) overexpression indicates a significant overlap of genes in these conditions. YAP1 is a transcriptional co-activator in the Hippo signaling pathway, and YAP1-induced transcriptional responses are essential in cancer cell proliferation. Here, we report that HIF-2α robustly increases YAP1 expression and activity in CRC-derived cell lines and in mouse models. The potentiation of YAP1 activity by HIF-2α was not via canonical signaling mechanisms such as Src (non-receptor tyrosine kinase), PI3K, ERK, or MAPK pathways. Moreover, we detected no direct interaction of HIF-2α with YAP1. Of note, YAP1 activation was critical for cancer cell growth under hypoxia. Our findings indicate that HIF-2α increases cancer cell growth by up-regulating YAP1 activity, suggesting that this pathway might be targeted in potential anti-cancer approaches for treating CRC patients. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. The role of hypoxia-inducible factor-1α and vascular endothelial growth factor in late-phase preconditioning with xenon, isoflurane and levosimendan in rat cardiomyocytes.

    Science.gov (United States)

    Goetzenich, Andreas; Hatam, Nima; Preuss, Stephanie; Moza, Ajay; Bleilevens, Christian; Roehl, Anna B; Autschbach, Rüdiger; Bernhagen, Jürgen; Stoppe, Christian

    2014-03-01

    The protective effects of late-phase preconditioning can be triggered by several stimuli. Unfortunately, the transfer from bench to bedside still represents a challenge, as concomitant medication or diseases influence the complex signalling pathways involved. In an established model of primary neonatal rat cardiomyocytes, we analysed the cardioprotective effects of three different stimulating pharmaceuticals of clinical relevance. The effect of additional β-blocker treatment was studied as these were previously shown to negatively influence preconditioning. Twenty-four hours prior to hypoxia, cells pre-treated with or without metoprolol (0.55 µg/ml) were preconditioned with isoflurane, levosimendan or xenon. The influences of these stimuli on hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) as well as inducible and endothelial nitric synthase (iNOS/eNOS) and cyclooxygenase-2 (COX-2) were analysed by polymerase chain reaction and western blotting. The preconditioning was proved by trypan blue cell counts following 5 h of hypoxia and confirmed by fluorescence staining. Five hours of hypoxia reduced cell survival in unpreconditioned control cells to 44 ± 4%. Surviving cell count was significantly higher in cells preconditioned either by 2 × 15 min isoflurane (70 ± 16%; P = 0.005) or by xenon (59 ± 8%; P = 0.049). Xenon-preconditioned cells showed a significantly elevated content of VEGF (0.025 ± 0.010 IDV [integrated density values when compared with GAPDH] vs 0.003 ± 0.006 IDV in controls; P = 0.0003). The protein expression of HIF-1α was increased both by levosimendan (0.563 ± 0.175 IDV vs 0.142 ± 0.042 IDV in controls; P = 0.0289) and by xenon (0.868 ± 0.222 IDV; P xenon but not by the other chosen stimuli. eNOS mRNA expression was found to be suppressed by β-blocker treatment for all stimuli. In our model, independently of the chosen stimulus, β-blocker treatment had no significant effect on cell survival. We found

  9. Therapeutic treatment with a novel hypoxia-inducible factor hydroxylase inhibitor (TRC160334 ameliorates murine colitis

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    Gupta R

    2014-01-01

    Full Text Available Ram Gupta,1 Anita R Chaudhary,2 Binita N Shah,1 Avinash V Jadhav,3 Shitalkumar P Zambad,1 Ramesh Chandra Gupta,4 Shailesh Deshpande,4 Vijay Chauthaiwale,4 Chaitanya Dutt4 1Department of Pharmacology, 2Cellular and Molecular Biology, 3Preclinical Safety Evaluation, 4Discovery, Torrent Research Centre, Torrent Pharmaceuticals Ltd, Gandhinagar, Gujarat, India Background and aim: Mucosal healing in inflammatory bowel disease (IBD can be achieved by improvement of intestinal barrier protection. Activation of hypoxia-inducible factor (HIF has been identified as a critical factor for barrier protection during mucosal insult and is linked with improvement in symptoms of colitis. Although prophylactic efficacy of HIF hydroxylase inhibitors in murine colitis have been established, its therapeutic efficacy in clinically relevant therapeutic settings have not been established. In the present study we aim to establish therapeutic efficacy of TRC160334, a novel HIF hydroxylase inhibitor, in animal models of colitis. Methods: The efficacy of TRC160334 was evaluated in two different mouse models of colitis by oral route. A prophylactic efficacy study was performed in a 2,4,6-trinitrobenzene sulfonic acid-induced mouse model of colitis representing human Crohn's disease pathology. Additionally, a therapeutic efficacy study was performed in a dextran sulfate sodium-induced mouse model of colitis, a model simulating human ulcerative colitis. Results: TRC160334 treatment resulted in significant improvement in disease end points in both models of colitis. TRC160334 treatment resulted into cytoprotective heatshock protein 70 induction in inflamed colon. TRC160334 successfully attenuated the rate of fall in body weight, disease activity index, and macroscopic and microscopic scores of colonic damage leading to overall improvement in study outcome. Conclusion: Our findings are the first to demonstrate that therapeutic intervention with a HIF hydroxylase inhibitor

  10. Protective effects of myricetin on acute hypoxia-induced exercise intolerance and mitochondrial impairments in rats.

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    Dan Zou

    Full Text Available Exercise tolerance is impaired in hypoxia. The aim of this study was to evaluate the effects of myricetin, a dietary flavonoid compound widely found in fruits and vegetables, on acute hypoxia-induced exercise intolerance in vivo and in vitro.Male rats were administered myricetin or vehicle for 7 days and subsequently spent 24 hours at a barometric pressure equivalent to 5000 m. Exercise capacity was then assessed through the run-to-fatigue procedure, and mitochondrial morphology in skeletal muscle cells was observed by transmission electron microscopy (TEM. The enzymatic activities of electron transfer complexes were analyzed using an enzyme-linked immuno-sorbent assay (ELISA. mtDNA was quantified by real-time-PCR. Mitochondrial membrane potential was measured by JC-1 staining. Protein expression was detected through western blotting, immunohistochemistry, and immunofluorescence.Myricetin supplementation significantly prevented the decline of run-to-fatigue time of rats in hypoxia, and attenuated acute hypoxia-induced mitochondrial impairment in skeletal muscle cells in vivo and in vitro by maintaining mitochondrial structure, mtDNA content, mitochondrial membrane potential, and activities of the respiratory chain complexes. Further studies showed that myricetin maintained mitochondrial biogenesis in skeletal muscle cells under hypoxic conditions by up-regulating the expressions of mitochondrial biogenesis-related regulators, in addition, AMP-activated protein kinase(AMPK plays a crucial role in this process.Myricetin may have important applications for improving physical performance under hypoxic environment, which may be attributed to the protective effect against mitochondrial impairment by maintaining mitochondrial biogenesis.

  11. Suppression of Phosphatidylinositol 3-Kinase/Akt Signaling Attenuates Hypoxia-Induced Pulmonary Hypertension Through the Downregulation of Lysyl Oxidase.

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    Xia, Xiao-Dong; Lee, Jasmine; Khan, Sajid; Ye, Leping; Li, Yuan; Dong, Liang

    2016-10-01

    Lysyl oxidase (LOX) is a copper-dependent enzyme that catalyzes covalent cross-linking of collagen. In response to hypoxia, phosphatidylinositol 3-kinase (PI3K) pathway is activated and contributes to pulmonary arterial hypertension (PAH). However, potential role of LOX in hypoxia-induced PAH is poorly understood. In this study, we explored the mechanism responsible for the development of hypoxia-induced PAH. Potent inhibitors of PI3K/Akt and LOX, wortmannin and β-aminopropionitrile (β-APN), were administrated in rat model of hypoxia-induced PAH. The cross-linking of collagen was assessed by the determination of hydroxyproline. LOX, LOXL-1, LOXL-2, LOXL-3, LOXL-4, Akt, and phospho-Akt expression was detected by real-time polymerase chain reaction and western blot analysis. We observed that collagen cross-linking and LOX activity were elevated in hypoxia-exposed rat lung tissue, but these effects were reversed by β-APN and wortmannin. In addition, exposure to hypoxia enhanced mRNA and protein expression and activity of LOX and LOXL-1 in a PI3K/Akt-dependent manner and induced the development of PAH. After the administration of wortmannin, the upregulation of LOX and cross-linking of collagen were significantly reversed in hypoxia-exposed rat pulmonary artery tissue. Taken together, the present study demonstrated that the upregulation of LOX expression and collagen cross-linking is PI3K/Akt dependent in rat with hypoxia-induced PAH. Suppression of PI3K/Akt pathway may alleviate hypoxia-induced PAH through the downregulation of LOX.

  12. Brazilian Green Propolis Suppresses the Hypoxia-Induced Neuroinflammatory Responses by Inhibiting NF-κB Activation in Microglia

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    Zhou Wu

    2013-01-01

    Full Text Available Hypoxia has been recently proposed as a neuroinflammatogen, which drives microglia to produce proinflammatory cytokines, including interleukin-1β (IL-1β, tumor necrosis factor-α (TNF-α, and IL-6. Considering the fact that propolis has hepatoprotective, antitumor, antioxidative, and anti-inflammatory effects, propolis may have protective effects against the hypoxia-induced neuroinflammatory responses. In this study, propolis (50 μg/mL was found to significantly inhibit the hypoxia-induced cytotoxicity and the release of proinflammatory cytokines, including IL-1β, TNF-α, and IL-6, by MG6 microglia following hypoxic exposure (1% O2, 24 h. Furthermore, propolis significantly inhibited the hypoxia-induced generation of reactive oxygen species (ROS from mitochondria and the activation of nuclear factor-κB (NF-κB in microglia. Moreover, systemic treatment with propolis (8.33 mg/kg, 2 times/day, i.p. for 7 days significantly suppressed the microglial expression of IL-1β, TNF-α, IL-6, and 8-oxo-deoxyguanosine, a biomarker for oxidative damaged DNA, in the somatosensory cortex of mice subjected to hypoxia exposure (10% O2, 4 h. These observations indicate that propolis suppresses the hypoxia-induced neuroinflammatory responses through inhibition of the NF-κB activation in microglia. Furthermore, increased generation of ROS from the mitochondria is responsible for the NF-κB activation. Therefore, propolis may be beneficial in preventing hypoxia-induced neuroinflammation.

  13. Hypoxia-targeted triple suicide gene therapy radiosensitizes human colorectal cancer cells.

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    Hsiao, Hung Tsung; Xing, Ligang; Deng, Xuelong; Sun, Xiaorong; Ling, C Clifton; Li, Gloria C

    2014-08-01

    The hypoxic microenvironment, an important feature of human solid tumors but absent in normal tissue, may provide an opportunity for cancer-specific gene therapy. The purpose of the present study was to investigate whether hypoxia-driven triple suicide gene TK/CD/UPRT expression enhances cytotoxicity to ganciclovir (GCV) and 5-fluorocytosine (5-FC), and sensitizes human colorectal cancer to radiation in vitro and in vivo. Stable transfectant of human colorectal HCT8 cells was established which expressed hypoxia-inducible vectors (HRE-TK/eGFP and HRE-CD/UPRT/mDsRed). Hypoxia-induced expression/function of TK, CD and UPRT was verified by western blot analysis, flow cytometry, fluorescent microscopy and cytotoxicity assay of GCV and 5-FC. Significant radiosensitization effects were detected after 5-FC and GCV treatments under hypoxic conditions. In the tumor xenografts, the distribution of TK/eGFP and CD/UPRT/mDsRed expression visualized with fluorescence microscopy was co-localized with the hypoxia marker pimonidazole positive staining cells. Furthermore, administration of 5-FC and GCV in mice in combination with local irradiation resulted in tumor regression, as compared with prodrug or radiation treatments alone. Our data suggest that the hypoxia-inducible TK/GCV+CDUPRT/5-FC triple suicide gene therapy may have the ability to specifically target hypoxic cancer cells and significantly improve the tumor control in combination with radiotherapy.

  14. STARS knockout attenuates hypoxia-induced pulmonary arterial hypertension by suppressing pulmonary arterial smooth muscle cell proliferation.

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    Shi, Zhaoling; Wu, Huajie; Luo, Jianfeng; Sun, Xin

    2017-03-01

    STARS (STriated muscle Activator of Rho Signaling) is a sarcomeric protein, which expressed early in cardiac development and involved in pathological remodeling. Abundant evidence indicated that STARS could regulate cell proliferation, but it's exact function remains unclear. In this study, we aimed to investigate the role of STARS in the proliferation of pulmonary arterial smooth muscle cells (PASMC) and the potential effect on the progression of pulmonary arterial hypertension (PAH). In this study, we established a PAH mouse model through chronic hypoxia exposure as reflected by the increased RVSP and RVHI. Western blot and RT-qPCR detected the increased STARS protein and mRNA levels in PAH mice. Next, we cultured the primary PASMC from PAH mice. After STARS overexpression in PASMC, STARS, SRF and Egr-1 were up-regulated significantly. The MTT assay revealed an increase in cell proliferation. Flow cytometry showed a marked inhibition of cell apoptosis. However, STARS silence in PASMC exerted opposite effects with STARS overexpression. SRF siRNA transfection blocked the effects of STARS overexpression in PASMC. In order to further confirm the role of STARS in PAH mice in vivo, we exposed STARS knockout mice to hypoxia and found lower RVSP and RVHI in knockout mice as compared with controls. Our results not only suggest that STARS plays a crucial role in the development of PAH by increasing the proliferation of PASMC through activation of the SRF/Egr-1 pathway, but also provides a new mechanism for hypoxia-induced PAH. In addition, STARS may represent a potential treatment target. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  15. Oral Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitor Roxadustat (FG-4592) for the Treatment of Anemia in Patients with CKD.

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    Provenzano, Robert; Besarab, Anatole; Sun, Chao H; Diamond, Susan A; Durham, John H; Cangiano, Jose L; Aiello, Joseph R; Novak, James E; Lee, Tyson; Leong, Robert; Roberts, Brian K; Saikali, Khalil G; Hemmerich, Stefan; Szczech, Lynda A; Yu, Kin-Hung Peony; Neff, Thomas B

    2016-06-06

    Roxadustat (FG-4592), an oral hypoxia-inducible factor prolyl hydroxylase inhibitor that stimulates erythropoiesis, regulates iron metabolism, and reduces hepcidin, was evaluated in this phase 2b study for safety, efficacy, optimal dose, and dose frequency in patients with nondialysis CKD. The 145 patients with nondialysis CKD and hemoglobin ≤10.5 g/dl were randomized into one of six cohorts of approximately 24 patients each with varying roxadustat starting doses (tiered weight and fixed amounts) and frequencies (two and three times weekly) followed by hemoglobin maintenance with roxadustat one to three times weekly. Treatment duration was 16 or 24 weeks. Intravenous iron was prohibited. The primary end point was the proportion of patients achieving hemoglobin increase of ≥1.0 g/dl from baseline and hemoglobin of ≥11.0 g/dl by week 17 (16 weeks of treatment). Secondary analyses included mean hemoglobin change from baseline, iron utilization, and serum lipids. Safety was evaluated by frequency/severity of adverse events. Of the 145 patients enrolled, 143 were evaluable for efficacy. Overall, 92% of patients achieved hemoglobin response. Higher compared with lower starting doses led to earlier achievement of hemoglobin response. Roxadustat-induced hemoglobin increases were independent of baseline C-reactive protein levels and iron repletion status. Overall, over the first 16 treatment weeks, hepcidin levels decreased by 16.9% (P=0.004), reticulocyte hemoglobin content was maintained, and hemoglobin increased by a mean (±SD) of 1.83 (±0.09) g/dl (Proxadustat were well tolerated and achieved anemia correction with reduced serum hepcidin levels. After anemia correction, hemoglobin was maintained by roxadustat at various dose frequencies without intravenous iron supplementation. Copyright © 2016 by the American Society of Nephrology.

  16. Role of hypoxia inducing factor-1β in alcohol-induced autophagy, steatosis and liver injury in mice.

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    Hong-Min Ni

    Full Text Available Chronic alcohol causes liver hypoxia and steatosis, which eventually develops into alcoholic liver disease (ALD. While it has been known that alcohol consumption activates hepatic hypoxia inducing factor-1α (HIF-1α, conflicting results regarding the role of HIF-1α in alcohol-induced liver injury and steatosis in mice have been reported. In the present study, we aimed to use hepatocyte-specific HIF-1β knockout mice to eliminate the possible compensatory effects of the single knockout of the 1α subunit of HIF to study the role of HIFs in ALD. C57BL/6 wild type mice were treated with acute ethanol to mimic human binge drinking. Matched wild-type and hepatocyte specific HIF-1β knockout mice were also subjected to a recently established Gao-binge alcohol model to mimic chronic plus binge conditions, which is quite common in human alcoholics. We found that acute alcohol treatment increased BNIP3 and BNIP3L/NIX expression in primary cultured hepatocytes and in mouse livers, suggesting that HIF may be activated in these models. We further found that hepatocyte-specific HIF-1β knockout mice developed less steatosis and liver injury following the Gao-binge model or acute ethanol treatment compared with their matched wild type mice. Mechanistically, protection against Gao-binge treatment-induced steatosis and liver injury was likely associated with increased FoxO3a activation and subsequent induction of autophagy in hepatocyte-specific HIF-1β knockout mice.

  17. [Altered expressions of alkane monooxygenase and hypoxia inducible factor-1α expression in lung tissue of rat hypoxic pulmonary hypertension].

    Science.gov (United States)

    Deng, Hua-jun; Yuan, Ya-dong

    2013-10-29

    To explore the altered expressions of alkane monooxygenase (AlkB) and hypoxia-inducible factor-1α (HIF-1α) in a rat model of hypoxic pulmonary arterial hypertension. Twenty Wistar rats were divided randomly into normal control and hypoxia groups after 1-week adaptive feeding. Hypoxia group was raised in a homemade organic glass tank with a 24-h continuous supply of air and nitrogen atmospheric mixed gas. And the oxygen concentration of (10.0 ± 0.5)% was controlled by oxygen monitoring control system. The control group was maintained in room air. Both groups stayed in the same room with the same diet. After 8 weeks, the level of mean pulmonary pressure (mPAP) was measured by right-heart catheterization, right ventricular hypertrophy index (RVHI) calculated by the ratio of right ventricle to left ventricle plus septum and hypoxic pulmonary vascular remodeling (HPSR) observed under microscope. And the levels of AlkB and HIF-1α mRNA and protein in lungs were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot. At 8 weeks post-hypoxia, compared with the control group [11.0 ± 0.7 mm Hg (1 mm Hg = 0.133 kPa), 0.210 ± 0.035], the levels of mPAP and RVHI in hypoxia group (33.3 ± 1.3 mm Hg, 0.448 ± 0.013) increased significantly (both P pulmonary tissue decreased significantly (0.338 ± 0.085 vs 0.688 ± 0.020, P pulmonary hypertension.

  18. Effect of chemokine receptor CXCR4 on hypoxia-induced pulmonary hypertension and vascular remodeling in rats

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    Hales Charles A

    2011-02-01

    Full Text Available Abstract Background CXCR4 is the receptor for chemokine CXCL12 and reportedly plays an important role in systemic vascular repair and remodeling, but the role of CXCR4 in development of pulmonary hypertension and vascular remodeling has not been fully understood. Methods In this study we investigated the role of CXCR4 in the development of pulmonary hypertension and vascular remodeling by using a CXCR4 inhibitor AMD3100 and by electroporation of CXCR4 shRNA into bone marrow cells and then transplantation of the bone marrow cells into rats. Results We found that the CXCR4 inhibitor significantly decreased chronic hypoxia-induced pulmonary hypertension and vascular remodeling in rats and, most importantly, we found that the rats that were transplanted with the bone marrow cells electroporated with CXCR4 shRNA had significantly lower mean pulmonary pressure (mPAP, ratio of right ventricular weight to left ventricular plus septal weight (RV/(LV+S and wall thickness of pulmonary artery induced by chronic hypoxia as compared with control rats. Conclusions The hypothesis that CXCR4 is critical in hypoxic pulmonary hypertension in rats has been demonstrated. The present study not only has shown an inhibitory effect caused by systemic inhibition of CXCR4 activity on pulmonary hypertension, but more importantly also has revealed that specific inhibition of the CXCR4 in bone marrow cells can reduce pulmonary hypertension and vascular remodeling via decreasing bone marrow derived cell recruitment to the lung in hypoxia. This study suggests a novel therapeutic approach for pulmonary hypertension by inhibiting bone marrow derived cell recruitment.

  19. Inhibition of vascular endothelial growth factor A and hypoxia-inducible factor 1α maximizes the effects of radiation in sarcoma mouse models through destruction of tumor vasculature.

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    Lee, Hae-June; Yoon, Changhwan; Park, Do Joong; Kim, Yeo-Jung; Schmidt, Benjamin; Lee, Yoon-Jin; Tap, William D; Eisinger-Mathason, T S Karin; Choy, Edwin; Kirsch, David G; Simon, M Celeste; Yoon, Sam S

    2015-03-01

    To examine the addition of genetic or pharmacologic inhibition of hypoxia-inducible factor 1α (HIF-1α) to radiation therapy (RT) and vascular endothelial growth factor A (VEGF-A) inhibition (ie trimodality therapy) for soft-tissue sarcoma. Hypoxia-inducible factor 1α was inhibited using short hairpin RNA or low metronomic doses of doxorubicin, which blocks HIF-1α binding to DNA. Trimodality therapy was examined in a mouse xenograft model and a genetically engineered mouse model of sarcoma, as well as in vitro in tumor endothelial cells (ECs) and 4 sarcoma cell lines. In both mouse models, any monotherapy or bimodality therapy resulted in tumor growth beyond 250 mm(3) within the 12-day treatment period, but trimodality therapy with RT, VEGF-A inhibition, and HIF-1α inhibition kept tumors at <250 mm(3) for up to 30 days. Trimodality therapy on tumors reduced HIF-1α activity as measured by expression of nuclear HIF-1α by 87% to 95% compared with RT alone, and cytoplasmic carbonic anhydrase 9 by 79% to 82%. Trimodality therapy also increased EC-specific apoptosis 2- to 4-fold more than RT alone and reduced microvessel density by 75% to 82%. When tumor ECs were treated in vitro with trimodality therapy under hypoxia, there were significant decreases in proliferation and colony formation and increases in DNA damage (as measured by Comet assay and γH2AX expression) and apoptosis (as measured by cleaved caspase 3 expression). Trimodality therapy had much less pronounced effects when 4 sarcoma cell lines were examined in these same assays. Inhibition of HIF-1α is highly effective when combined with RT and VEGF-A inhibition in blocking sarcoma growth by maximizing DNA damage and apoptosis in tumor ECs, leading to loss of tumor vasculature. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Inhibition of Vascular Endothelial Growth Factor A and Hypoxia-Inducible Factor 1α Maximizes the Effects of Radiation in Sarcoma Mouse Models Through Destruction of Tumor Vasculature

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    Lee, Hae-June [Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Yoon, Changhwan [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Park, Do Joong [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Surgery, Seoul National University Bundang Hospital, Sungnam (Korea, Republic of); Kim, Yeo-Jung [Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Schmidt, Benjamin [Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Lee, Yoon-Jin [Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Tap, William D. [Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Eisinger-Mathason, T.S. Karin [Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Choy, Edwin [Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Kirsch, David G. [Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Simon, M. Celeste [Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Howard Hughes Medical Institute (United States); and others

    2015-03-01

    Purpose: To examine the addition of genetic or pharmacologic inhibition of hypoxia-inducible factor 1α (HIF-1α) to radiation therapy (RT) and vascular endothelial growth factor A (VEGF-A) inhibition (ie trimodality therapy) for soft-tissue sarcoma. Methods and Materials: Hypoxia-inducible factor 1α was inhibited using short hairpin RNA or low metronomic doses of doxorubicin, which blocks HIF-1α binding to DNA. Trimodality therapy was examined in a mouse xenograft model and a genetically engineered mouse model of sarcoma, as well as in vitro in tumor endothelial cells (ECs) and 4 sarcoma cell lines. Results: In both mouse models, any monotherapy or bimodality therapy resulted in tumor growth beyond 250 mm{sup 3} within the 12-day treatment period, but trimodality therapy with RT, VEGF-A inhibition, and HIF-1α inhibition kept tumors at <250 mm{sup 3} for up to 30 days. Trimodality therapy on tumors reduced HIF-1α activity as measured by expression of nuclear HIF-1α by 87% to 95% compared with RT alone, and cytoplasmic carbonic anhydrase 9 by 79% to 82%. Trimodality therapy also increased EC-specific apoptosis 2- to 4-fold more than RT alone and reduced microvessel density by 75% to 82%. When tumor ECs were treated in vitro with trimodality therapy under hypoxia, there were significant decreases in proliferation and colony formation and increases in DNA damage (as measured by Comet assay and γH2AX expression) and apoptosis (as measured by cleaved caspase 3 expression). Trimodality therapy had much less pronounced effects when 4 sarcoma cell lines were examined in these same assays. Conclusions: Inhibition of HIF-1α is highly effective when combined with RT and VEGF-A inhibition in blocking sarcoma growth by maximizing DNA damage and apoptosis in tumor ECs, leading to loss of tumor vasculature.

  1. A comparative gene expression database for invertebrates

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    Ormestad Mattias

    2011-08-01

    Full Text Available Abstract Background As whole genome and transcriptome sequencing gets cheaper and faster, a great number of 'exotic' animal models are emerging, rapidly adding valuable data to the ever-expanding Evo-Devo field. All these new organisms serve as a fantastic resource for the research community, but the sheer amount of data, some published, some not, makes detailed comparison of gene expression patterns very difficult to summarize - a problem sometimes even noticeable within a single lab. The need to merge existing data with new information in an organized manner that is publicly available to the research community is now more necessary than ever. Description In order to offer a homogenous way of storing and handling gene expression patterns from a variety of organisms, we have developed the first web-based comparative gene expression database for invertebrates that allows species-specific as well as cross-species gene expression comparisons. The database can be queried by gene name, developmental stage and/or expression domains. Conclusions This database provides a unique tool for the Evo-Devo research community that allows the retrieval, analysis and comparison of gene expression patterns within or among species. In addition, this database enables a quick identification of putative syn-expression groups that can be used to initiate, among other things, gene regulatory network (GRN projects.

  2. Interaction between obesity and the Hypoxia Inducible Factor 3 Alpha Subunit rs3826795 polymorphism in relation with plasma alanine aminotransferase.

    Science.gov (United States)

    Wang, Shuo; Song, Jieyun; Yang, Yide; Zhang, Yining; Chawla, Nitesh V; Ma, Jun; Wang, Haijun

    2017-07-28

    Hypoxia Inducible Factor 3 Alpha Subunit (HIF3A) DNA has been demonstrated to be associated with obesity in the methylation level, and it also has a Body Mass Index (BMI)-independent association with plasma alanine aminotransferase (ALT). However, the relation among obesity, plasma ALT, HIF3A polymorphism and methylation remains unclear. This study aims to identify the association between HIF3A polymorphism and plasma ALT, and further to determine whether the effect of HIF3A polymorphism on ALT could be modified by obesity or mediated by DNA methylation. The HIF3A rs3826795 polymorphism was genotyped in a case-control study including 2030 Chinese children aged 7-18 years (705 obese cases and 1325 non-obese controls). Furthermore, the HIF3A DNA methylation of the peripheral blood was measured in 110 severely obese children and 110 age- and gender- matched normal-weight controls. There was no overall association between the HIF3A rs3826795 polymorphism and ALT. A significant interaction between obesity and rs3826795 in relation with ALT was found (P inter  = 0.042), with rs3826795 G-allele number elevating ALT significantly only in obese children (β' = 0.075, P = 0.037), but not in non-obese children (β' = -0.009, P = 0.741). Additionally, a mediation effect of HIF3A methylation was found in the association between the HIF3A rs3826795 polymorphism and ALT among obese children (β' = 0.242, P = 0.014). This is the first study to report the interaction between obesity and HIF3A gene in relation with ALT, and also to reveal a mediation effect among the HIF3A polymorphism, methylation and ALT. This study provides new evidence to the function of HIF3A gene, which would be helpful for future risk assessment and personalized treatment of liver diseases.

  3. The hypoxia-inducible factor-1? activates ectopic production of fibroblast growth factor 23 in tumor-induced osteomalacia

    OpenAIRE

    Zhang, Qian; Doucet, Michele; Tomlinson, Ryan E; Han, Xiaobin; Quarles, L Darryl; Collins, Michael T; Clemens, Thomas L

    2016-01-01

    Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome in which ectopic production of fibroblast growth factor 23 (FGF23) by non-malignant mesenchymal tumors causes phosphate wasting and bone fractures. Recent studies have implicated the hypoxia-inducible factor-1? (HIF-1?) in other phosphate wasting disorders caused by elevated FGF23, including X-linked hypophosphatemic rickets and autosomal dominant hypophosphatemia. Here we provide evidence that HIF-1? mediates aberrant FGF23 i...

  4. [Effects of RNAi on hypoxia inducible factor-1alpha activity and proliferation of hypoxic pulmonary artery smooth muscle cells in rat].

    Science.gov (United States)

    Zhang, Wei; Cao, Yue; Zhang, Yu; Ma, Qi-Sheng; Ma, Lan; Ge, Ri-Li

    2006-02-25

    Pulmonary vascular remodeling is one of the major characteristics of hypoxia-induced pulmonary hypertension, mainly represented by over-proliferation of pulmonary artery smooth muscle cells (PASMCs). Hypoxia inducible factor-1alpha (HIF-1alpha) is a transcription factor which is produced by the cells exposed to hypoxia. HIF-1alpha up-regulates the expression of many hypoxia response genes (HRGs) for the body to adapt to hypoxia and maintain homeostasis. The expression of HIF-1alpha in the PASMCs is remarkably elevated under hypoxic condition and it stimulates the proliferation of PASMCs. In this experiment, we used gene clone technology to design and synthesize two siRNAs based on the sequence of HIF-1alpha mRNA. They were separately subcloned into the plasmid of pGenesil-1 containing U6 promoter. The pGenesil-1 vector of the RNA interference eukaryotic expression vector specific to HIF-1alpha gene was constructed. DNA sequencing of the plasmid verified the successful construction of the HIF-1alpha RNAi. We isolated and cultured the PASMCs of rat. The pGenesil-1 vector was transferred into the PASMCs with METAFECTENE in vitro. The positive cell clones transfected with pGenesil-1 were obtained after being screened with 400 mug/ml G418. These PASMCs were cultured in normoxia and hypoxia. After 48 h, the effects of RNAi on the expression of HIF-1alpha mRNA were detected by RT-PCR. The cellular growth activities were assayed by MTT colorimetry and flow cytometry in vitro. The results showed that for the PASMCs cultured in hypoxia for 48 h, the cell proliferation of blank group and control group were remarkably increased and the HIF-1alpha mRNA expressions were up-regulated, while the cell proliferation of the treatment groups did not increase and the HIF-1alpha mRNA expressions were not up-regulated. In conclusion, we successfully constructed the recombinant plasmid of RNAi and transfected them into the PASMCs in vitro. The RNAi inhibited the expression of HIF-1alpha m

  5. Deferoxamine Improves Alveolar and Pulmonary Vascular Development by Upregulating Hypoxia-inducible Factor-1α in a Rat Model of Bronchopulmonary Dysplasia.

    Science.gov (United States)

    Choi, Chang Won; Lee, Juyoung; Lee, Hyun Ju; Park, Hyoung-Sook; Chun, Yang-Sook; Kim, Beyong Il

    2015-09-01

    Fetal lung development normally occurs in a hypoxic environment. Hypoxia-inducible factor (HIF)-1α is robustly induced under hypoxia and transactivates many genes that are essential for fetal development. Most preterm infants are prematurely exposed to hyperoxia, which can halt hypoxia-driven lung maturation. We were to investigate whether the HIF-1α inducer, deferoxamine (DFX) can improve alveolarization in a rat model of bronchopulmonary dysplasia (BPD). A rat model of BPD was produced by intra-amniotic lipopolysaccharide (LPS) administration and postnatal hyperoxia (85% for 7 days), and DFX (150 mg/kg/d) or vehicle was administered to rat pups intraperitoneally for 14 days. On day 14, the rat pups were sacrificed and their lungs were removed and examined. A parallel in vitro study was performed with a human small airway epithelial cell line to test whether DFX induces the expression of HIF-1α and its target genes. Alveolarization and pulmonary vascular development were impaired in rats with BPD. However, DFX significantly ameliorated these effects. Immunohistochemical analysis showed that HIF-1α was significantly upregulated in the lungs of BPD rats treated with DFX. DFX was also found to induce HIF-1α in human small airway epithelial cells and to promote the expression of HIF-1α target genes. Our data suggest that DFX induces and activates HIF-1α, thereby improving alveolarization and vascular distribution in the lungs of rats with BPD.

  6. Parallel Regulation of von Hippel-Lindau Disease by pVHL-Mediated Degradation of B-Myb and Hypoxia-Inducible Factor α

    Science.gov (United States)

    Uematsu, Keiji; Byrne, Stuart D.; Hirano, Mie; Joo-Okumura, Akiko; Nishikimi, Akihiko; Shuin, Taro; Fukui, Yoshinori; Nakatsukasa, Kunio

    2016-01-01

    pVHL, the protein product of the von Hippel-Lindau (VHL) tumor suppressor gene, is a ubiquitin ligase that targets hypoxia-inducible factor α (HIF-α) for proteasomal degradation. Although HIF-α activation is necessary for VHL disease pathogenesis, constitutive activation of HIF-α alone did not induce renal clear cell carcinomas and pheochromocytomas in mice, suggesting the involvement of an HIF-α-independent pathway in VHL pathogenesis. Here, we show that the transcription factor B-Myb is a pVHL substrate that is degraded via the ubiquitin-proteasome pathway and that vascular endothelial growth factor (VEGF)- and/or platelet-derived growth factor (PDGF)-dependent tyrosine 15 phosphorylation of B-Myb prevents its degradation. Mice injected with B-Myb knockdown 786-O cells developed dramatically larger tumors than those bearing control cell tumors. Microarray screening of B-Myb-regulated genes showed that the expression of HIF-α-dependent genes was not affected by B-Myb knockdown, indicating that B-Myb prevents HIF-α-dependent tumorigenesis through an HIF-α-independent pathway. These data indicate that the regulation of B-Myb by pVHL plays a critical role in VHL disease. PMID:27090638

  7. Gingerol-induced hypoxia-inducible factor 1 alpha inhibits human prion peptide-mediated neurotoxicity.

    Science.gov (United States)

    Jeong, Jae-Kyo; Moon, Myung-Hee; Park, Yang-Gyu; Lee, Ju-Hee; Lee, You-Jin; Seol, Jae-Won; Park, Sang-Youel

    2013-08-01

    Prion diseases are a family member of neurodegenerative disorders caused by the accumulation of misfolded-prion proteins (scrapie form of PrP, PrP(Sc)). The accumulation of PrP(Sc) in the brain leads to neurotoxicity by the induction of mitochondrial-apoptotic pathways. Recent studies implicated gingerol in protection against neurodegeneration. However, the basis of the neuroprotection in prion disease remains unclear. Thus, we investigated the influence of gingerol on prion peptide-induced neuronal damage. Gingerol blocked PrP(106-126)-mediated neurotoxicity by protecting mitochondrial function. Moreover, the protective effect of gingerol against PrP(106-126)-induced mitochondrial damage was associated with hypoxia-inducible factor 1 alpha (HIF-1α) expression. Gingerol-induced HIF-1α expression inhibited the PrP(106-126)-induced mitochondrial dysfunction. On the other hand, inhibition of gingerol-induced HIF-1 α expression attenuated the gingerol-mediated neuroprotective effect. Here, we demonstrate for the first time that treatment with gingerol prevents prion peptide-mediated neuronal cell death and that the neuroprotection is induced by HIF-1α-mediated signals. This study suggests that treatment with gingerol may provide a novel therapeutic strategy for prion-mediated neurotoxicity. Copyright © 2012 John Wiley & Sons, Ltd.

  8. Crocin attenuates acute hypobaric hypoxia-induced cognitive deficits of rats.

    Science.gov (United States)

    Zhang, Xiao-Yan; Zhang, Xian-Jun; Xv, Jin; Jia, Wei; Pu, Xiao-Yan; Wang, Hai-Yan; Liang, Hong; Zhuoma-Lamao; Lu, Dian-Xiang

    2018-01-05

    This study investigated whether crocin exerted neuroprotective effects against acute hypobaric hypoxia at high altitude in vivo and determined the underlying mechanisms. Male Sprague-Dawley rats were randomly assigned to a normoxic group,a hypoxic group, and three crocin groups at three different doses. The rats were transferred from 50m to 4200m for 3 days after treatment with crocin for 3 days. The learning and memory of the rat were evaluated with the Morris water maze test. Transmission electron microscope (TEM) was used to analyze the changes in the ultrastructure of hippocampal neurons. Peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α) and sirtuin-1 (SIRT1) levels were determined using immunohistochemical staining and western blotting. The escape latency of the crocin group was shorter than that of the hypoxic group, while the frequency of the rats reaching the platform was significantly higher in the crocin group. The structures of nerve cells and mitochondria were destroyed in the hypoxic group, but were repaired in the crocin groups. The expressions of PGC-1α and SIRT1 were decreased in the hypoxic group, but were increased in the crocin group. All the effects improved by crocin were dose-dependent. Crocin attenuates acute hypobaric hypoxia-induced cognitive deficits in rats, accompanied by repairing the structures of hippocampal neurons and improving PGC-1α and SIRT1 levels. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Leukemia kidney infiltration can cause secondary polycythemia by activating hypoxia-inducible factor (HIF) pathway.

    Science.gov (United States)

    Osumi, Tomoo; Awazu, Midori; Fujimura, Eriko; Yamazaki, Fumito; Hashiguchi, Akinori; Shimada, Hiroyuki

    2013-06-01

    Secondary polycythemia with increased production of erythropoietin (EPO) is known to occur in kidney diseases such as hydronephrosis and cystic disease, but the mechanism remains unclear. We report an 18-year-old female with isolated renal relapse of acute lymphoblastic leukemia accompanied by polycythemia. At the relapse, she presented with bilateral nephromegaly, mild renal dysfunction, and erythrocytosis with increased serum EPO levels up to 52.1 mIU/mL (9.1-32.8). Renal biopsy demonstrated diffuse lymphoblastic infiltration. The expression of hypoxia-inducible factor (HIF)-1α, which is undetectable in normal kidney, was observed in the renal tubule epithelium compressed by lymphoblastic cells. These findings suggest that erythrocytosis was caused by renal ischemia due to leukemic infiltration. Polycythemia probably became apparent because of the lack of leukemic involvement of the bone marrow. With chemotherapy, the serum EPO level rapidly decreased to normal range accompanied by the normalization of kidney size and function. Renal leukemic infiltration may enhance EPO production, although not recognized in the majority of cases because of bone marrow involvement. Our case has clarified the mechanism of previously reported polycythemia associated with renal diseases as renal ischemia. Furthermore, we have added renal ischemia resulting from tumor infiltration to the list of causes of secondary polycythemia.

  10. Roles of hypoxia inducible factor-1α in the temporomandibular joint.

    Science.gov (United States)

    Mino-Oka, Akiko; Izawa, Takashi; Shinohara, Takehiro; Mori, Hiroki; Yasue, Akihiro; Tomita, Shuhei; Tanaka, Eiji

    2017-01-01

    Temporomandibular joint osteoarthritis (TMJ-OA) is a degenerative disease characterized by permanent cartilage loss. Articular cartilage is maintained in a low-oxygen environment. The chondrocyte response to hypoxic conditions involves expression of hypoxia inducible factor 1α (HIF-1α), which induces chondrocytes to increase expression of vascular endothelial growth factor (VEGF). Here, we investigated the role of HIF-1α in mechanical load effects on condylar cartilage and subchondral bone in heterozygous HIF-1α-deficient mice (HIF-1α+/-). Mechanical stress was applied to the TMJ of C57BL/6NCr wild-type (WT) and HIF-1α+/- mice with a sliding plate for 10 days. Histological analysis was performed by HE staining, Safranin-O/Fast green staining, and immunostaining specific for articular cartilage homeostasis. HIF-1α+/- mice had thinner cartilage and smaller areas of proteoglycan than WT controls, without and with mechanical stress. Mechanical stress resulted in prominent degenerative changes with increased expression of HIF-1α, VEGF, and the apoptosis factor cleaved Caspase-3 in condylar cartilage. Our results indicate that HIF-1α may be important for articular cartilage homeostasis and protective against articular cartilage degradation in the TMJ under mechanical stress condition, therefore HIF-1α could be an important new therapeutic target in TMJ-OA. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Hypoxia inducible factor: a potential prognostic biomarker in oral squamous cell carcinoma.

    Science.gov (United States)

    Qian, Jiang; Wenguang, Xu; Zhiyong, Wang; Yuntao, Zou; Wei, Han

    2016-08-01

    Oral squamous cell carcinoma (OSCC) is the most common oral cancer. Hypoxia inducible factor (HIF) is involved in many malignant tumors' growth and metastasis and upregulated by hypoxia, including oral cancer. Many studies have studied about the prognostic value of HIF expression in OSCC; however, they do not get the consistent results. Therefore, this study explored the correlation between the HIF expression and the prognosis of OSCC. It conducted a meta-analysis of relevant publications searched in the Web of Science, PubMed, and ISI Web of Knowledge databases. Totally, this study identified 12 relevant articles reporting a total of 1112 patients. This analysis revealed a significant association between increased risk of mortality (RR = 1.20; 95 % CI 0.74-1.95; I (2) 85.4 %) and overexpression of HIFs. Furthermore, different HIF isoforms were associated with overall survival [HIF-1α (RR = 1.18; 95 % CI 0.66-2.11; I (2) 87.2 %) and HIF-2α (RR = 1.40; 95 % CI 0.93-2.09; I(2) 0.0 %)]. These results show that overexpression of HIFs, regardless of whether the HIF-1α or HIF-2α isoforms are overexpressed is significantly associated with increased risk of mortality in OSCC patients. In this study, the funnel is symmetric, suggesting existed no publication bias.

  12. Crosstalk between nitric oxide and hypoxia-inducible factor signaling pathways: an update

    Directory of Open Access Journals (Sweden)

    Hendrickson MD

    2015-06-01

    Full Text Available Marina D Hendrickson, Robert O Poyton Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, USA Abstract: Hypoxia-inducible factor-1 (HIF-1 is responsible for cellular adaptations to hypoxia. While oxygen (O2 negatively regulates its stability, many other factors affect HIF-1 stability and activity, including nitric oxide (NO. NO derived from l-arginine and nitrite (NO2– could nitrosylate or nitrate HIF-1 and multiple proteins involved in HIF-1 regulation, and can allow HIF-1 to escape normoxic degradation. In turn, HIF-1 can increase NO production through multiple mechanisms, including increased inducible nitric oxide synthase (iNOS expression and subunit 4-2 of cytochrome c oxidase (COX4-2 expression. There is therefore a high degree of crosstalk between HIF-1 and NO signaling. As such, many cellular responses to NO are mediated by HIF-1, and vice versa. This includes, but is not limited to, angiogenesis, apoptosis, senescence, and metabolic changes. These pathways all have important functions in normal physiology and when altered can contribute or, in some cases, lead to pathogenesis. Keywords: HIF, nitric oxide, Cco/NO mitochondrial signaling, ROS/RNS, cancer

  13. Hypoxia-Inducible Factor-1 as a Therapeutic Target in Endometrial Cancer Management

    Directory of Open Access Journals (Sweden)

    Laura M. S. Seeber

    2010-01-01

    Full Text Available In the Western world, endometrial cancer (EC is the most common malignant tumor of the female genital tract. Solid tumors like EC outgrow their vasculature resulting in hypoxia. Tumor hypoxia is important because it renders an aggressive phenotype and leads to radio- and chemo-therapy resistance. Hypoxia-inducible factor-1 (HIF-1 plays an essential role in the adaptive cellular response to hypoxia and is associated with poor clinical outcome in EC. Therefore, HIF-1 could be an attractive therapeutic target. Selective HIF-1 inhibitors have not been identified. A number of nonselective inhibitors which target signaling pathways upstream or downstream HIF-1 are known to decrease HIF-1 protein levels. In clinical trials for the treatment of advanced and/or recurrent EC are the topoisomerase I inhibitor Topotecan, mTOR-inhibitor Rapamycin, and angiogenesis inhibitor Bevacizumab. Preliminary data shows encouraging results for these agents. Further work is needed to identify selective HIF-1 inhibitors and to translate these into clinical trials.

  14. Fucoidan Suppresses Hypoxia-Induced Lymphangiogenesis and Lymphatic Metastasis in Mouse Hepatocarcinoma

    Directory of Open Access Journals (Sweden)

    Hongming Teng

    2015-06-01

    Full Text Available Metastasis, the greatest clinical challenge associated with cancer, is closely connected to multiple biological processes, including invasion and adhesion. The hypoxic environment in tumors is an important factor that causes tumor metastasis by activating HIF-1α. Fucoidan, extracted from brown algae, is a sulfated polysaccharide and, as a novel marine biological material, has been used to treat various disorders in China, Korea, Japan and other countries. In the present study, we demonstrated that fucoidan derived from Undaria pinnatifida sporophylls significantly inhibits the hypoxia-induced expression, nuclear translocation and activity of HIF-1α, the synthesis and secretion of VEGF-C and HGF, cell invasion and lymphatic metastasis in a mouse hepatocarcinoma Hca-F cell line. Fucoidan also suppressed lymphangiogenesis in vitro and in vivo. In addition, accompanied by a reduction in the HIF-1α nuclear translocation and activity, fucoidan significantly reduced the levels of p-PI3K, p-Akt, p-mTOR, p-ERK, NF-κB, MMP-2 and MMP-9, but increased TIMP-1 levels. These results indicate strongly that the anti-metastasis and anti-lymphangiogenesis activities of fucoidan are mediated by suppressing HIF-1α/VEGF-C, which attenuates the PI3K/Akt/mTOR signaling pathways.

  15. hypoxia-inducible factors activate CD133 promoter through ETS family transcription factors.

    Directory of Open Access Journals (Sweden)

    Shunsuke Ohnishi

    Full Text Available CD133 is a cellular surface protein that has been reported to be a cancer stem cell marker, and thus it is considered to be a potential target for cancer treatment. However, the mechanism regulating CD133 expression is not yet understood. In this study, we analyzed the activity of five putative promoters (P1-P5 of CD133 in human embryonic kidney (HEK 293 cells and colon cancer cell line WiDr, and found that the activity of promoters, particularly of P5, is elevated by overexpression of hypoxia-inducible factors (HIF-1α and HIF-2α. Deletion and mutation analysis identified one of the two E-twenty six (ETS binding sites (EBSs in the P5 region as being essential for its promoter activity induced by HIF-1α and HIF-2α. In addition, a chromatin imunoprecipitation assay demonstrated that HIF-1α and HIF-2α bind to the proximal P5 promoter at the EBSs. The immunoprecipitation assay showed that HIF-1α physically interacts with Elk1; however, HIF-2α did not bind to Elk1 or ETS1. Furthermore, knockdown of both HIF-1α and HIF-2α resulted in a reduction of CD133 expression in WiDr. Taken together, our results revealed that HIF-1α and HIF-2α activate CD133 promoter through ETS proteins.

  16. Methylseleninic acid downregulates hypoxia-inducible factor-1α in invasive prostate cancer.

    Science.gov (United States)

    Sinha, Indu; Null, Kevin; Wolter, William; Suckow, Mark A; King, Tonya; Pinto, John T; Sinha, Raghu

    2012-03-15

    Alternative strategies are needed to control growth of advanced and hormone refractory prostate cancer. In this regard, we investigated the efficacy of methylseleninic acid (MSeA), a penultimate precursor to the highly reactive selenium metabolite, methylselenol, to inhibit growth of invasive and hormone refractory rat (PAIII) and human (PC-3 and PC-3M) prostate cancer cells. Our results demonstrate that MSeA inhibits PAIII cell growth in vitro as well as reduces weights of tumors generated by PAIII cells treated ex vivo. A significant reduction in the number of metastatic lung foci by MSeA treatment was also noted in Lobund-Wistar rats. The PAIII cells along with PC-3, DU145 and PC-3M cells undergo apoptosis after MSeA treatments in both normoxia and hypoxia. Treatment of metastatic rat and human prostate cancer cell lines with MSeA decreased hypoxia-inducible factor-1α (HIF-1α) levels in a dose-dependent manner. Additionally, HIF-1α transcription activity both in normoxic and hypoxic conditions is reduced after MSeA treatment of prostate cancer cells. Furthermore, VEGF and GLUT1, downstream targets of HIF-1α, were also reduced in prostate cancer cells after MSeA treatment. Our study illustrates the efficacy of MSeA in controlling growth of hormone refractory prostate cancer by downregulating HIF-1α, which is possibly occurring through stabilization or increase in prolyl hydroxylase activity. Copyright © 2011 UICC.

  17. A Brief Overview of Nitric Oxide and Reactive Oxygen Species Signaling in Hypoxia-Induced Pulmonary Hypertension.

    Science.gov (United States)

    Jaitovich, Ariel; Jourd'heuil, David

    2017-01-01

    Pulmonary hypertension (PH) is characterized by increased vasoconstriction and smooth muscle cell hyperplasia driving pathological vascular remodeling of arterial vessels. In this short review, we discuss the primary source of reactive oxygen species (ROS) and nitric oxide (NO) relevant to PH and the mechanism by which dysregulation of their production contributes to PH. Specifically, hypoxia-induced PH is associated with diminished endothelial nitric oxide synthase (eNOS)-derived NO production and increased production of superoxide (O 2 •- ) through eNOS uncoupling and defective mitochondrial respiration. This drives the inhibition of the NO/soluble guanylate cyclase (sGC) pathway and activation of the transcription factor hypoxia-inducible factor-1α (HIF-1α) with consequential dysregulation of the pulmonary vasculature. Therapeutics aimed at increasing NO or cGMP bioavailabilities are amenable to hypoxia disease-induced PH. Similarly, strategies targeting HIF-1α are now considered. Overall, pulmonary hypertension including hypoxia-induced PH offers unique opportunities for the rational development of therapeutics centered on modulating redox signaling.

  18. The importance of GLUT3 for de novo lipogenesis in hypoxia-induced lipid loading of human macrophages.

    Directory of Open Access Journals (Sweden)

    Lu Li

    Full Text Available Atherosclerotic lesions are characterized by lipid-loaded macrophages (foam cells and hypoxic regions. Although it is well established that foam cells are produced by uptake of cholesterol from oxidized LDL, we previously showed that hypoxia also promotes foam cell formation even in the absence of exogenous lipids. The hypoxia-induced lipid accumulation results from increased triglyceride biosynthesis but the exact mechanism is unknown. Our aim was to investigate the importance of glucose in promoting hypoxia-induced de novo lipid synthesis in human macrophages. In the absence of exogenous lipids, extracellular glucose promoted the accumulation of Oil Red O-stained lipid droplets in human monocyte-derived macrophages in a concentration-dependent manner. Lipid droplet accumulation was higher in macrophages exposed to hypoxia at all assessed concentrations of glucose. Importantly, triglyceride synthesis from glucose was increased in hypoxic macrophages. GLUT3 was highly expressed in macrophage-rich and hypoxic regions of human carotid atherosclerotic plaques and in macrophages isolated from these plaques. In human monocyte-derived macrophages, hypoxia increased expression of both GLUT3 mRNA and protein, and knockdown of GLUT3 with siRNA significantly reduced both glucose uptake and lipid droplet accumulation. In conclusion, we have shown that hypoxia-induced increases in glucose uptake through GLUT3 are important for lipid synthesis in macrophages, and may contribute to foam cell formation in hypoxic regions of atherosclerotic lesions.

  19. Effect of all-trans-retinoic acid on the development of chronic hypoxia-induced pulmonary hypertension.

    Science.gov (United States)

    Zhang, Erquan; Jiang, Baohua; Yokochi, Ayumu; Maruyama, Junko; Mitani, Yoshihide; Ma, Ning; Maruyama, Kazuo

    2010-08-01

    An earlier study showed that all-trans-retinoic acid (ATRA) prevents the development of monocrotalin-induced pulmonary hypertension (PH). The purpose of the present study was to determine the effect of ATRA on another model of chronic hypoxia-induced PH. Male Sprague-Dawley rats were given 30 mg/kg ATRA or vehicle only by gavage once daily for 14 days during hypobaric hypoxic exposure. Chronic hypoxic exposure induced PH, right ventricular hypertrophy (RVH), and hypertensive pulmonary vascular changes. Quantitative morphometry of the pulmonary arteries showed that ATRA treatment significantly reduced the percentage of muscularized arteries in peripheral pulmonary arteries only with an external diameter between 15 and 50 microm. ATRA treatment also significantly reduced the medial wall thickness in small muscular arteries only with an external diameter between 50 and 100 microm. Unfortunately, these reductions did not accompany the lowering of pulmonary artery pressure nor decrease in RVH. Chronic hypoxia-induced PH rats with ATRA had a loss in body weight. Chronic hypoxia increased the expression of endothelial nitric oxide synthase in the lung on western blotting and immunohistochemistry, in which ATRA treatment had no effect. The administration of ATRA might not have a therapeutic role in preventing the development of chronic hypoxia-induced PH, because of body weight loss and the subtle preventable effects of vascular changes.

  20. [Inhibitory effect of salidroside on hypoxia-induced apoptosis of corpus cavernosum smooth muscle cells in rats].

    Science.gov (United States)

    Zhao, Jian-Feng; Fu, Hui-Ying; Yang, Fan; Huang, Xiao-Jun; Chen, Gang; Lü, Bo-Dong

    2014-04-01

    To investigate the effect of salidroside on hypoxia-induced apoptosis of corpus cavernosum smooth muscle cells (CCSMCs) in rats. Rat CCSMCs were cultured in vitro by the enzyme digestion method and identified by immunofluorescent staining of anti-alpha-SMA and anti-Desmin. The non-toxic dose of salidroside was determined by MTT assay. Low-oxygen mixed gas (1% O2, 5% CO2, and 94% N2) was piped into a modular incubator chamber to induce hypoxia. The CCSMCs were divided into a normal, a hypoxia, and a 32 microg/mL salidroside intervention group. The apoptosis of the CCSMCs was detected by flow cytometry and the expression of the caspase-3 protein determined by Western blot. The majority of the CCSMCs were positive for alpha-SMA and Desmin at immunofluorescent staining. Salidroside at salidroside significantly reduced hypoxia-induced early apoptosis of CCSMCs ([13.46% +/- 1.87]%, P Salidroside can reduce the expression of cleaved caspase-3 and inhibit hypoxia-induced apoptosis of CCSMCs in rats.

  1. Salidroside attenuates chronic hypoxia-induced pulmonary hypertension via adenosine A2a receptor related mitochondria-dependent apoptosis pathway.

    Science.gov (United States)

    Huang, Xiaoying; Zou, Lizhen; Yu, Xiaoming; Chen, Mayun; Guo, Rui; Cai, Hui; Yao, Dan; Xu, Xiaomei; Chen, Yanfan; Ding, Cheng; Cai, Xueding; Wang, Liangxing

    2015-05-01

    Pulmonary arterial hypertension (PAH) is characterized by pulmonary arterial remodeling mainly due to excess cellular proliferation and apoptosis resistance of pulmonary arterial smooth muscle cells (PASMCs). Salidroside, an active ingredient isolated from Rhodiola rosea is proposed to exert protective effects against PAH. However, the function of salidroside in PAH has not been investigated systematically and the underlying mechanisms are not clear. To investigate the effects of salidroside on PAH, the mice in chronic hypoxia model of PAH were given by an increasing concentration of salidroside (0, 16 mg/kg, 32 mg/kg, and 64 mg/kg). After salidroside treatment, the chronic hypoxia-induced right ventricular hypertrophy and pulmonary arterial remodeling were attenuated, suggesting a protective role played by salidroside in PAH. To explore the potential mechanisms, the apoptosis of PASMCs after salidroside treatment under hypoxia conditions were determined in vivo and in vitro, and also the mitochondria-dependent apoptosis factors, Bax, Bcl-2, cytochrome C, and caspase 9 were examined. The results revealed that salidroside reversed hypoxia-induced cell apoptosis resistance at least partially via a mitochondria-dependent pathway. In addition, salidroside upregulated the expression of adenosine A2a receptor (A2aR) in lung tissues of mice and in PASMCs in vitro after hypoxia exposure. Combined the evidence above, we conclude that salidroside can attenuate chronic hypoxia-induced PAH by promoting PASMCs apoptosis via an A2aR related mitochondria dependent pathway. Copyright © 2015. Published by Elsevier Ltd.

  2. Compound C prevents Hypoxia-Inducible Factor-1α protein stabilization by regulating the cellular oxygen availability via interaction with Mitochondrial Complex I

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    Hagen Thilo

    2011-04-01

    Full Text Available Abstract The transcription factor Hypoxia-Inducible Factor-1α is a master regulator of the cellular response to low oxygen concentration. Compound C, an inhibitor of AMP-activated kinase, has been reported to inhibit hypoxia dependent Hypoxia-Inducible Factor-1α activation via a mechanism that is independent of AMP-activated kinase but dependent on its interaction with the mitochondrial electron transport chain. The objective of this study is to characterize the interaction of Compound C with the mitochondrial electron transport chain and to determine the mechanism through which the drug influences the stability of the Hypoxia-Inducible Factor-1α protein. We found that Compound C functions as an inhibitor of complex I of the mitochondrial electron transport chain as demonstrated by its effect on mitochondrial respiration. It also prevents hypoxia-induced Hypoxia-Inducible Factor-1α stabilization in a dose dependent manner. In addition, Compound C does not have significant effects on reactive oxygen species production from complex I via both forward and reverse electron flux. This study provides evidence that similar to other mitochondrial electron transport chain inhibitors, Compound C regulates Hypoxia-Inducible Factor-1α stability by controlling the cellular oxygen concentration.

  3. Comparative gene expression between two yeast species

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    Guan Yuanfang

    2013-01-01

    Full Text Available Abstract Background Comparative genomics brings insight into sequence evolution, but even more may be learned by coupling sequence analyses with experimental tests of gene function and regulation. However, the reliability of such comparisons is often limited by biased sampling of expression conditions and incomplete knowledge of gene functions across species. To address these challenges, we previously systematically generated expression profiles in Saccharomyces bayanus to maximize functional coverage as compared to an existing Saccharomyces cerevisiae data repository. Results In this paper, we take advantage of these two data repositories to compare patterns of ortholog expression in a wide variety of conditions. First, we developed a scalable metric for expression divergence that enabled us to detect a significant correlation between sequence and expression conservation on the global level, which previous smaller-scale expression studies failed to detect. Despite this global conservation trend, between-species gene expression neighborhoods were less well-conserved than within-species comparisons across different environmental perturbations, and approximately 4% of orthologs exhibited a significant change in co-expression partners. Furthermore, our analysis of matched perturbations collected in both species (such as diauxic shift and cell cycle synchrony demonstrated that approximately a quarter of orthologs exhibit condition-specific expression pattern differences. Conclusions Taken together, these analyses provide a global view of gene expression patterns between two species, both in terms of the conditions and timing of a gene's expression as well as co-expression partners. Our results provide testable hypotheses that will direct future experiments to determine how these changes may be specified in the genome.

  4. miR-138 protects cardiomyocytes from hypoxia-induced apoptosis via MLK3/JNK/c-jun pathway

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    He, Siyi; Liu, Peng; Jian, Zhao; Li, Jingwei; Zhu, Yun; Feng, Zezhou; Xiao, Yingbin, E-mail: xiaoyb@vip.sina.com

    2013-11-29

    Highlights: •First time to find miR-138 is up-regulated in hypoxic cardiomyocytes. •First time to find miR-138 targets MLK3 and regulates JNK/c-jun pathway. •Rare myocardial biopsy of patients with CHD were collected. •Both silence and overexpression of miR-138 were implemented. •Various methods were used to detect cell function. -- Abstract: Cardiomyocytes experience a series of complex endogenous regulatory mechanisms against apoptosis induced by chronic hypoxia. MicroRNAs are a class of endogenous small non-coding RNAs that regulate cellular pathophysiological processes. Recently, microRNA-138 (miR-138) has been found related to hypoxia, and beneficial for cell proliferation. Therefore, we intend to study the role of miR-138 in hypoxic cardiomyocytes and the main mechanism. Myocardial samples of patients with congenital heart disease (CHD) were collected to test miR-138 expression. Agomir or antagomir of miR-138 was transfected into H9C2 cells to investigate its effect on cell apoptosis. Higher miR-138 expression was observed in patients with cyanotic CHD, and its expression gradually increased with prolonged hypoxia time in H9C2 cells. Using MTT and LDH assays, cell growth was significantly greater in the agomir group than in the negative control (NC) group, while antagomir decreased cell survival. Dual luciferase reporter gene and Western-blot results confirmed MLK3 was a direct target of miR-138. It was found that miR-138 attenuated hypoxia-induced apoptosis using TUNEL, Hoechst staining and Annexin V-PE/7-AAD flow cytometry analysis. We further detected expression of apoptosis-related proteins. In the agomir group, the level of pro-apoptotic proteins such as cleaved-caspase-3, cleaved-PARP and Bad significantly reduced, while Bcl-2 and Bcl-2/Bax ratio increased. Opposite changes were observed in the antagomir group. Downstream targets of MLK3, JNK and c-jun, were also suppressed by miR-138. Our study demonstrates that up-regulation of miR-138 plays

  5. Expression and function of hypoxia inducible factor-1 alpha in human melanoma under non-hypoxic conditions

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    Joshi Sandeep S

    2009-11-01

    Full Text Available Abstract Background Hypoxia inducible factor-1 alpha (HIF-1α protein is rapidly degraded under normoxic conditions. When oxygen tensions fall HIF-1α protein stabilizes and transactivates genes involved in adaptation to hypoxic conditions. We have examined the normoxic expression of HIF-1α RNA and protein in normal human melanocytes and a series of human melanoma cell lines isolated from radial growth phase (RGP, vertical growth phase (VGP and metastatic (MET melanomas. Results HIF-1α mRNA and protein was increased in RGP vs melanocytes, VGP vs RGP and MET vs VGP melanoma cell lines. We also detected expression of a HIF-1α mRNA splice variant that lacks part of the oxygen-dependent regulation domain in WM1366 and WM9 melanoma cells. Over-expression of HIF-1α and its splice variant in the RGP cell line SbCl2 resulted in a small increase in soft agar colony formation and a large increase in matrigel invasion relative to control transfected cells. Knockdown of HIF-1α expression by siRNA in the MET WM9 melanoma cell line resulted in a large decrease in both soft agar colony formation and matrigel invasion relative to cells treated with non-specific siRNA. There is a high level of ERK1/2 phosphorylation in WM9 cells, indicating an activated Ras-Raf-MEK-ERK1/2 MAPK pathway. Treatment of WM9 cells with 30 μM U0126 MEK inhibitor, decreased ERK1/2 phosphorylation and resulted in a decrease in HIF-1α expression. However, a 24 h treatment with 10 μM U0126 totally eliminated Erk1/2 phosphorylation, but did not change HIF-1alpha levels. Furthermore, siRNA knockdown of MEK siRNA did not change HIF-1alpha levels. Conclusion We speculate that metabolic products of U0126 decrease HIF-1alpha expression through "off target" effects. Overall our data suggest that increased HIF-1α expression under normoxic conditions contributes to some of the malignant phenotypes exhibited by human melanoma cells. The expanded role of HIF-1α in melanoma biology increases

  6. Hypoxia-inducible factor 1alpha determines gastric cancer chemosensitivity via modulation of p53 and NF-kappaB.

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    Nadine Rohwer

    Full Text Available BACKGROUND: Reduced chemosensitivity of solid cancer cells represents a pivotal obstacle in clinical oncology. Hence, the molecular characterization of pathways regulating chemosensitivity is a central prerequisite to improve cancer therapy. The hypoxia-inducible factor HIF-1alpha has been linked to chemosensitivity while the underlying molecular mechanisms remain largely elusive. Therefore, we comprehensively analysed HIF-1alpha's role in determining chemosensitivity focussing on responsible molecular pathways. METHODOLOGY AND PRINCIPAL FINDINGS: RNA interference was applied to inactivate HIF-1alpha or p53 in the human gastric cancer cell lines AGS and MKN28. The chemotherapeutic agents 5-fluorouracil and cisplatin were used and chemosensitivity was assessed by cell proliferation assays as well as determination of cell cycle distribution and apoptosis. Expression of p53 and p53 target proteins was analyzed by western blot. NF-kappaB activity was characterized by means of electrophoretic mobility shift assay. Inactivation of HIF-1alpha in gastric cancer cells resulted in robust elevation of chemosensitivity. Accordingly, HIF-1alpha-competent cells displayed a significant reduction of chemotherapy-induced senescence and apoptosis. Remarkably, this phenotype was completely absent in p53 mutant cells while inactivation of p53 per se did not affect chemosensitivity. HIF-1alpha markedly suppressed chemotherapy-induced activation of p53 and p21 as well as the retinoblastoma protein, eventually resulting in cell cycle arrest. Reduced formation of reactive oxygen species in HIF-1alpha-competent cells was identified as the molecular mechanism of HIF-1alpha-mediated inhibition of p53. Furthermore, loss of HIF-1alpha abrogated, in a p53-dependent manner, chemotherapy-induced DNA-binding of NF-kappaB and expression of anti-apoptotic NF-kappaB target genes. Accordingly, reconstitution of the NF-kappaB subunit p65 reversed the increased chemosensitivity of

  7. KAJIAN PERAN MANGANESE-CONTAINING SUPER OXIDE DISMUTASE (MNSOD DALAM REGULASI EKSPRESI HYPOXIA INDUCIBLE FACTOR-1α (HIF-1α PADA KEADAAN HIPOKSIA

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    Masagus Zainuri

    2014-02-01

    Full Text Available AbstrakKekurangan suplai oksigen pada jaringan disebut hipoksia. Sel tumor sering mengalami hipoksia dan menjadi tidak responsif terhadap terapi. Keadaan hipoksia pada jaringan tumor perlu ditanggulangi agar keberhasilan terapi tumor dapat  ditingkatkan.  Pada keadaan hipoksia,  factor  Hypoxia Inducible Factor-1α  (HIF-1α berperan  penting  dalam pengendalian respon selular. Ekspresi gen HIF-1α sangat dipengaruhi oleh status redoks sel. Enzim MnSOD merupakan enzim antioksidan endogen yang berperan sebagai scavenger O2.-yang menghasilkan H2O2 dan O2 , sehingga aktivitas MnSOD akan mempengaruhi status redoks dari sel. Melalui O2.-dan H2O2, MnSOD memiliki peran biphasic terhadap regulasi ekspresi gen HIF-1α, sehingga dapat menekan dampak hipoksia pada jaringan. Sampai saat ini MnSOD belum dimanfaatkan  sebagai  terapi  pendukung  pada  terapi tumor  dan  perlu  dilakukan  banyak  eksperimen  untuk mengeksplorasi potensi MnSOD sebagai terapi adjuvant alternative untuk terapi tumor.Kata Kunci : MnSOD, HIF-1α, Superoksida (O2.-, Hidrogen Peroksida (H2O2AbstractInsufficient oxygen supply in tissue is named hypoxia. Tumor cells frequentlyexperience tissue hypoxia, therefore it becomes irresponsive to the main therapy. Hypoxia of tumor tissue needs to be solved to improve the tumor therapy succeed. In hypoxia, Hypoxia Inducible Factor-1α (HIF-1α plays an essential role in controlling the cellular responses. HIF-1α  gene  expression  is  influenced  by  the  redox stateof the cells. MnSOD enzyme is an endogenous antioxidant enzyme that acting as an O2.-scavenger that producing H2O2 and O2, so that MnSOD activity would affect the redox state of the cells. ViaO2.-and H2O2, MnSOD has a biphasic role for gene expression of HIF-1α regulation and reducing the tissue hypoxia effect. Recently, MnSOD is not an adjuvant therapy for tumor treatment yet, and some experiments are needed to explore MnSOD potential as an alternative

  8. Paradoxical regulation of hypoxia inducible factor-1α (HIF-1α by histone deacetylase inhibitor in diffuse large B-cell lymphoma.

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    Savita Bhalla

    Full Text Available Hypoxia inducible factor (HIF is important in cancer, as it regulates various oncogenic genes as well as genes involved in cell survival, proliferation, and migration. Elevated HIF-1 protein promotes a more aggressive tumor phenotype, and greater HIF-1 expression has been demonstrated to correlate with poorer prognosis, increased risk of metastasis and increased mortality. Recent reports suggest that HIF-1 activates autophagy, a lysosomal degradation pathway which may promote tumor cell survival. We show here that HIF-1α expression is constitutively active in multiple diffuse large B cell lymphoma (DLBCL cell lines under normoxia and it is regulated by the PI3K/AKT pathway. PCI-24781, a pan histone deacetylase inhibitor (HDACI, enhanced accumulation of HIF-1α and induced autophagy initially, while extended incubation with the drug resulted in inhibition of HIF-1α. We tested the hypothesis that PCI-24781- induced autophagy is mediated by HIF-1α and that inhibition of HIF-1α in these cells results in attenuation of autophagy and decreased survival. We also provide evidence that autophagy serves as a survival pathway in DLBCL cells treated with PCI-24781 which suggests that the use of autophagy inhibitors such as chloroquine or 3-methyl adenine in combination with PCI-24781 may enhance apoptosis in lymphoma cells.

  9. Phase 2 studies of oral hypoxia-inducible factor prolyl hydroxylase inhibitor FG-4592 for treatment of anemia in China.

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    Chen, Nan; Qian, Jiaqi; Chen, Jianghua; Yu, Xueqing; Mei, Changlin; Hao, Chuanming; Jiang, Gengru; Lin, Hongli; Zhang, Xinzhou; Zuo, Li; He, Qiang; Fu, Ping; Li, Xuemei; Ni, Dalvin; Hemmerich, Stefan; Liu, Cameron; Szczech, Lynda; Besarab, Anatole; Neff, Thomas B; Peony Yu, Kin-Hung; Valone, Frank H

    2017-08-01

    FG-4592 (roxadustat) is an oral hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor (HIF-PHI) promoting coordinated erythropoiesis through the transcription factor HIF. Two Phase 2 studies were conducted in China to explore the safety and efficacy of FG-4592 (USAN name: roxadustat, CDAN name: ), a HIF-PHI, in patients with anemia of chronic kidney disease (CKD), both patients who were dialysis-dependent (DD) and patients who were not dialysis-dependent (NDD). In the NDD study, 91 participants were randomized to low (1.1-1.75 mg/kg) or high (1.50-2.25 mg/kg) FG-4592 starting doses or to placebo. In the DD study, 87 were enrolled to low (1.1-1.8 mg/kg), medium (1.5-2.3 mg/kg) and high (1.7-2.3 mg/kg) starting FG-4592 doses or to continuation of epoetin alfa. In both studies, only oral iron supplementation was allowed. In the NDD study, hemoglobin (Hb) increase ≥1 g/dL from baseline was achieved in 80.0% of subjects in the low-dose cohort and 87.1% in the high-dose cohort, versus 23.3% in the placebo arm (P < 0.0001, both). In the DD study, 59.1%, 88.9% (P = 0.008) and 100% (P = 0.0003) of the low-, medium- and high-dose subjects maintained their Hb levels after 5- and 6-weeks versus 50% of the epoetin alfa-treated subjects. In both studies, significant reductions in cholesterol were noted in FG-4592-treated subjects, with stability or increases in serum iron, total iron-binding capacity (TIBC) and transferrin (without intravenous iron administration). In the NDD study, hepcidin levels were significantly reduced across all FG-4592-treated arms as compared with no change in the placebo arm. In the DD study, hepcidin levels were also reduced in a statistically significant dose-dependent manner in the highest dose group as compared with the epoetin alfa-treated group. Adverse events were similar for FG-4592-treated and control subjects. FG-4592 may prove an effective alternative for managing anemia of CKD. It is currently being

  10. Tanshinone IIA inhibits hypoxia-induced pulmonary artery smooth muscle cell proliferation via Akt/Skp2/p27-associated pathway.

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    Ying Luo

    Full Text Available We previously showed that tanshinone IIA ameliorated the hypoxia-induced pulmonary hypertension (HPH partially by attenuating pulmonary artery remodeling. The hypoxia-induced proliferation of pulmonary artery smooth muscle cells (PASMCs is one of the major causes for pulmonary arterial remodeling, therefore the present study was performed to explore the effects and underlying mechanism of tanshinone IIA on the hypoxia-induced PASMCs proliferation. PASMCs were isolated from male Sprague-Dawley rats and cultured in normoxic (21% or hypoxic (3% condition. Cell proliferation was measured with 3 - (4, 5 - dimethylthiazal - 2 - yl - 2, 5 - diphenyltetrazoliumbromide assay and cell counting. Cell cycle was measured with flow cytometry. The expression of of p27, Skp-2 and the phosphorylation of Akt were measured using western blot and/or RT-PCR respectively. The results showed that tanshinone IIA significantly inhibited the hypoxia-induced PASMCs proliferation in a concentration-dependent manner and arrested the cells in G1/G0-phase. Tanshinone IIA reversed the hypoxia-induced reduction of p27 protein, a cyclin-dependent kinase inhibitor, in PASMCs by slowing down its degradation. Knockdown of p27 with specific siRNA abolished the anti-proliferation of tanshinone IIA. Moreover, tanshinone IIA inhibited the hypoxia-induced increase of S-phase kinase-associated protein 2 (Skp2 and the phosphorylation of Akt, both of which are involved in the degradation of p27 protein. In vivo tanshinone IIA significantly upregulated the hypoxia-induced p27 protein reduction and downregulated the hypoxia-induced Skp2 increase in pulmonary arteries in HPH rats. Therefore, we propose that the inhibition of tanshinone IIA on hypoxia-induce PASMCs proliferation may be due to arresting the cells in G1/G0-phase by slowing down the hypoxia-induced degradation of p27 via Akt/Skp2-associated pathway. The novel information partially explained the anti-remodeling property of

  11. Endogenous markers of two separate hypoxia response pathways (hypoxia inducible factor 2 alpha and carbonic anhydrase 9) are associated with radiotherapy failure in head and neck cancer patients recruited in the CHART randomized trial.

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    Koukourakis, Michael I; Bentzen, Søren M; Giatromanolaki, Alexandra; Wilson, George D; Daley, Frances M; Saunders, Michele I; Dische, Stanley; Sivridis, Efthimios; Harris, Adrian L

    2006-02-10

    Randomized controlled trials have generally shown a benefit from accelerated radiotherapy in head and neck squamous cell carcinoma (HNSCC). However, the large randomized United Kingdom trial CHART (Continuous Hyperfractionated Accelerated Radiotherapy) failed to show a benefit of strongly accelerated over standard radiotherapy (RT) in 918 patients with HNSCC. In this study, we investigated the impact of tumor hypoxia on the outcome of HNSCC patients in the CHART trial. There are two distinct hypoxia inducible factors (HIFs) that control different gene response pathways and we assessed them both with endogenous markers of hypoxia, hypoxia inducible factor HIF-2 alpha (HIF-2) and carbonic anhydrase CA9, an indicator of HIF-1 alpha (HIF-1) function. Tissue from pre-RT biopsies performed in 198 of 918 patients recruited was analyzed for the immunohistochemical expression of HIF-2 and CA9. A significant association of high HIF2 and of high CA9 reactivity with poor locoregional control (P uni-directional hypothesis, that a benefit from randomization to CHART should be seen in the nonhypoxic tumors, was supported by the data (one-tailed P = .04). Expression of endogenous markers of hypoxia for the HIF-1 and HIF-2 pathway is strongly associated with radiotherapy failure. Using immunohistochemical methods it is possible to identify subgroups of HNSCC patients who are highly curable with radiotherapy, or who are excellent candidates for clinical trials on hypoxia-targeting drugs in two distinct pathways.

  12. Potent inhibition of tumoral hypoxia-inducible factor 1α by albendazole

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    Poruchynsky Marianne S

    2010-04-01

    Full Text Available Abstract Background Emerging reports suggest resistance, increased tumor invasiveness and metastasis arising from treatment with drugs targeting vascular endothelial growth factor (VEGF. It is believed that increased tumoral hypoxia plays a prominent role in the development of these phenomena. Inhibition of tumoral hypoxia inducible factor (HIF-1α is thus becoming an increasingly attractive therapeutic target in the treatment of cancer. We hypothesized that the anti-VEGF effect of albendazole (ABZ could be mediated through inhibition of tumoral HIF-1α. Method In vitro, the effects of ABZ on HIF-1α levels in human ovarian cancer cells (OVCAR-3 were investigated using hypoxic chamber or desferrioxamine (DFO induced-hypoxia. In vivo, the effects of ABZ (150 mg/kg, i.p., single dose on the tumor levels of HIF-1α and VEGF protein and mRNA were investigated by western blotting, RT-PCR and real time-PCR. Results In vitro, ABZ inhibited cellular HIF-1α protein accumulation resulting from placement of cells under hypoxic chamber or exposure to DFO. In vivo, tumors excised from vehicle treated mice showed high levels of both HIF-1α and VEGF. Whereas, tumoral HIF-1α and VEGF protein levels were highly suppressed in ABZ treated mice. Tumoral VEGFmRNA (but not HIF-1αmRNA was also found to be highly suppressed by ABZ. Conclusion These results demonstrate for the first time the effects of an acute dose of ABZ in profoundly suppressing both HIF-1α and VEGF within the tumor. This dual inhibition may provide additional value in inhibiting angiogenesis and be at least partially effective in inhibiting tumoral HIF-1α surge, tumor invasiveness and metastasis.

  13. Hypobaric hypoxia induced arginase expression limits nitric oxide availability and signaling in rodent heart.

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    Singh, Manjulata; Padhy, Gayatri; Vats, Praveen; Bhargava, Kalpana; Sethy, Niroj Kumar

    2014-06-01

    This study was aimed to evaluate regulation of cardiac arginase expression during hypobaric hypoxia and subsequent effect on nitric oxide availability and signaling. Rats were exposed to hypobaric hypoxia (282mmHg for 3h) and ARG1 expression was monitored. The expression levels of eNOS and eNOS(Ser1177) were determined by Western blotting, cGMP levels were measured by ELISA and amino acid concentrations were measured by HPLC analysis. Transcription regulation of arginase was monitored by chromatin immunoprecipitation (ChIP) assay with anti-c-Jun antibody for AP-1 consensus binding site on ARG1 promoter. Arginase activity was inhibited by intra-venous dose of N-(ω)-hydroxy-nor-l-arginine (nor-NOHA) prior to hypoxia exposure and subsequent effect on NO availability and oxidative stress were evaluated. Hypobaric hypoxia induced cardiac arginase expression by recruiting c-Jun to AP-1 binding site on ARG1 promoter. This increased expression redirected l-arginine towards arginase and resulted in limited endothelial nitric oxide synthase (eNOS) activity, nitric oxide (NO) availability and cGMP mediated signaling. Inhibition of arginase restored the eNOS activity, promoted cardiac NO availability and ameliorated peroxynitrite formation during hypoxia. Hypoxic induced arginase under transcription control of AP-1 reciprocally regulates eNOS activity and NO availability in the heart. This also results in cardiac oxidative stress. This study provides understanding of hypoxia-mediated transcriptional regulation of arginase expression in the heart and its subsequent effect on eNOS activity, NO availability and signaling as well as cardiac oxidative stress. This information will support the use of arginase inhibitors as therapeutics for pathological hypoxia. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Hypoxia inducible factor signaling modulates susceptibility to mycobacterial infection via a nitric oxide dependent mechanism.

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    Elks, Philip M; Brizee, Sabrina; van der Vaart, Michiel; Walmsley, Sarah R; van Eeden, Fredericus J; Renshaw, Stephen A; Meijer, Annemarie H

    2013-01-01

    Tuberculosis is a current major world-health problem, exacerbated by the causative pathogen, Mycobacterium tuberculosis (Mtb), becoming increasingly resistant to conventional antibiotic treatment. Mtb is able to counteract the bactericidal mechanisms of leukocytes to survive intracellularly and develop a niche permissive for proliferation and dissemination. Understanding of the pathogenesis of mycobacterial infections such as tuberculosis (TB) remains limited, especially for early infection and for reactivation of latent infection. Signaling via hypoxia inducible factor α (HIF-α) transcription factors has previously been implicated in leukocyte activation and host defence. We have previously shown that hypoxic signaling via stabilization of Hif-1α prolongs the functionality of leukocytes in the innate immune response to injury. We sought to manipulate Hif-α signaling in a well-established Mycobacterium marinum (Mm) zebrafish model of TB to investigate effects on the host's ability to combat mycobacterial infection. Stabilization of host Hif-1α, both pharmacologically and genetically, at early stages of Mm infection was able to reduce the bacterial burden of infected larvae. Increasing Hif-1α signaling enhanced levels of reactive nitrogen species (RNS) in neutrophils prior to infection and was able to reduce larval mycobacterial burden. Conversely, decreasing Hif-2α signaling enhanced RNS levels and reduced bacterial burden, demonstrating that Hif-1α and Hif-2α have opposing effects on host susceptibility to mycobacterial infection. The antimicrobial effect of Hif-1α stabilization, and Hif-2α reduction, were demonstrated to be dependent on inducible nitric oxide synthase (iNOS) signaling at early stages of infection. Our findings indicate that induction of leukocyte iNOS by stabilizing Hif-1α, or reducing Hif-2α, aids the host during early stages of Mm infection. Stabilization of Hif-1α therefore represents a potential target for therapeutic

  15. Hypoxia inducible factor signaling modulates susceptibility to mycobacterial infection via a nitric oxide dependent mechanism.

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    Philip M Elks

    Full Text Available Tuberculosis is a current major world-health problem, exacerbated by the causative pathogen, Mycobacterium tuberculosis (Mtb, becoming increasingly resistant to conventional antibiotic treatment. Mtb is able to counteract the bactericidal mechanisms of leukocytes to survive intracellularly and develop a niche permissive for proliferation and dissemination. Understanding of the pathogenesis of mycobacterial infections such as tuberculosis (TB remains limited, especially for early infection and for reactivation of latent infection. Signaling via hypoxia inducible factor α (HIF-α transcription factors has previously been implicated in leukocyte activation and host defence. We have previously shown that hypoxic signaling via stabilization of Hif-1α prolongs the functionality of leukocytes in the innate immune response to injury. We sought to manipulate Hif-α signaling in a well-established Mycobacterium marinum (Mm zebrafish model of TB to investigate effects on the host's ability to combat mycobacterial infection. Stabilization of host Hif-1α, both pharmacologically and genetically, at early stages of Mm infection was able to reduce the bacterial burden of infected larvae. Increasing Hif-1α signaling enhanced levels of reactive nitrogen species (RNS in neutrophils prior to infection and was able to reduce larval mycobacterial burden. Conversely, decreasing Hif-2α signaling enhanced RNS levels and reduced bacterial burden, demonstrating that Hif-1α and Hif-2α have opposing effects on host susceptibility to mycobacterial infection. The antimicrobial effect of Hif-1α stabilization, and Hif-2α reduction, were demonstrated to be dependent on inducible nitric oxide synthase (iNOS signaling at early stages of infection. Our findings indicate that induction of leukocyte iNOS by stabilizing Hif-1α, or reducing Hif-2α, aids the host during early stages of Mm infection. Stabilization of Hif-1α therefore represents a potential target for

  16. Expression of hypoxia-inducible factor-1α and erythropoietin at corneal neovascularization in rats

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    Ji-Min Wang

    2014-12-01

    Full Text Available AIM: To describe the expression of hypoxia-inducible factor-1α(HIF-1αand erythropoietin(EPOin rats' corneal and evaluate its potential effect on corneal neovascularization(CNVgrowth. METHODS: The young SD rats(3mowas chosen and randomly divided into 2 groups, which were experimental group and normal control group. CNV model was established by alkali burn, and the length and area of CNV was observed everyday after operation by slit lamp. After that, the expression of HIF-1α and EPO was measured by SABC and RT-PCR methods at 1, 3, 5, 7, and 14d after alkali burn. The data was analyzed by SPSS 20.0. RESULTS: The area of CNV was increasing at 1, 3, 5, 7, and 14d after alkali burn, and the peak point appear at 7d. The growth speed was decreased after 14d. SABC method told us that no HIF-1α and very tiny amount EPO was detected at normal rats' corneal. The expression of the two factors increased at 1d after alkali burn in corneal epithelium and endoderm. The results of RT-PCR showed that a few amounts of HIF-1α and EPO mRNA were detected at normal group. The expression of the two factors was increased at 3d after alkali burn, and the peak value was found at 7d, however, it was decreased at 14d. Statistical difference was found at different time(PCONCLUSION: HIF-1α and EPO is closely related to CNV.

  17. Wortmannin influences hypoxia-inducible factor-1 alpha expression and glycolysis in esophageal carcinoma cells.

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    Zeng, Ling; Zhou, Hai-Yun; Tang, Na-Na; Zhang, Wei-Feng; He, Gui-Jun; Hao, Bo; Feng, Ya-Dong; Zhu, Hong

    2016-05-28

    To investigate the influence of phosphatidylinositol-3-kinase protein kinase B (PI3K/AKT)-HIF-1α signaling pathway on glycolysis in esophageal carcinoma cells under hypoxia. Esophageal carcinoma cell lines Eca109 and TE13 were cultured under hypoxia environment, and the protein, mRNA and activity levels of hypoxia inducible factor-1 alpha (HIF-1α), glucose transporter 1, hexokinase-II, phosphofructokinase 2 and lactate dehydrogenase-A were determined. Supernatant lactic acid concentrations were also detected. The PI3K/AKT signaling pathway was then inhibited with wortmannin, and the effects of hypoxia on the expression or activities of HIF-1α, associated glycolytic enzymes and lactic acid concentrations were observed. Esophageal carcinoma cells were then transfected with interference plasmid with HIF-1α-targeting siRNA to assess impact of the high expression of HIF-1α on glycolysis. HIF-1α is highly expressed in the esophageal carcinoma cell lines tested, and with decreasing levels of oxygen, the expression of HIF-1α and the associated glycolytic enzymes and the extracellular lactic acid concentration were enhanced in the esophageal carcinoma cell lines Eca109 and TE13. In both normoxia and hypoxic conditions, the level of glycolytic enzymes and the secretion of lactic acid were both reduced by wortmannin. The expression and activities of glycolytic enzymes and the lactic acid concentration in cells were reduced by inhibiting HIF-1α, especially the decreasing level of glycolysis was significant under hypoxic conditions. The PI3K/AKT pathway and HIF-1α are both involved in the process of glycolysis in esophageal cancer cells.

  18. Hypoxia-inducible factor-1 α/platelet derived growth factor axis in HIV-associated pulmonary vascular remodeling

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    Bartolome Sonja

    2011-08-01

    Full Text Available Abstract Background Human immunodeficiency virus (HIV infected patients are at increased risk for the development of pulmonary arterial hypertension (PAH. Recent reports have demonstrated that HIV associated viral proteins induce reactive oxygen species (ROS with resultant endothelial cell dysfunction and related vascular injury. In this study, we explored the impact of HIV protein induced oxidative stress on production of hypoxia inducible factor (HIF-1α and platelet-derived growth factor (PDGF, critical mediators implicated in the pathogenesis of HIV-PAH. Methods The lungs from 4-5 months old HIV-1 transgenic (Tg rats were assessed for the presence of pulmonary vascular remodeling and HIF-1α/PDGF-BB expression in comparison with wild type controls. Human primary pulmonary arterial endothelial cells (HPAEC were treated with HIV-associated proteins in the presence or absence of pretreatment with antioxidants, for 24 hrs followed by estimation of ROS levels and western blot analysis of HIF-1α or PDGF-BB. Results HIV-Tg rats, a model with marked viral protein induced vascular oxidative stress in the absence of active HIV-1 replication demonstrated significant medial thickening of pulmonary vessels and increased right ventricular mass compared to wild-type controls, with increased expression of HIF-1α and PDGF-BB in HIV-Tg rats. The up-regulation of both HIF-1α and PDGF-B chain mRNA in each HIV-Tg rat was directly correlated with an increase in right ventricular/left ventricular+septum ratio. Supporting our in-vivo findings, HPAECs treated with HIV-proteins: Tat and gp120, demonstrated increased ROS and parallel increase of PDGF-BB expression with the maximum induction observed on treatment with R5 type gp-120CM. Pre-treatment of endothelial cells with antioxidants or transfection of cells with HIF-1α small interfering RNA resulted in abrogation of gp-120CM mediated induction of PDGF-BB, therefore, confirming that ROS generation and

  19. Histone demethylase JMJD1A promotes urinary bladder cancer progression by enhancing glycolysis through coactivation of hypoxia inducible factor 1α.

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    Wan, W; Peng, K; Li, M; Qin, L; Tong, Z; Yan, J; Shen, B; Yu, C

    2017-07-06

    High aerobic glycolysis not only provides energy to cancer cells, but also supports their anabolic growth. JMJD1A, a histone demethylase that specifically demethylates H3K9me1/2, is overexpressed in multiple cancers, including urinary bladder cancer (UBC). It is unclear whether JMJD1A could promote cancer cell growth through enhancing glycolysis. In this study, we found that downregulation of JMJD1A decreased UBC cell proliferation, colony formation and xenograft tumor growth. Knockdown of JMJD1A inhibited glycolysis by decreasing the expression of genes participated in glucose metabolism, including GLUT1, HK2, PGK1, PGM, LDHA and MCT4. Mechanistically, JMJD1A cooperated with hypoxia inducible factor 1α (HIF1α), an important transcription factor for glucose metabolism, to induce the glycolytic gene expression. JMJD1A was recruited to the promoter of glycolytic gene PGK1 to demethylate H3K9me2. However, the JMJD1A (H1120Y) mutant, which loses the demethylase activity, failed to cooperate with HIF1α to induce the glycolytic gene expression, and failed to demethylate H3K9me2 on PGK1 promoter, suggesting that the demethylase activity of JMJD1A is essential for its coactivation function for HIF1α. Inhibition of glycolysis through knocking down HIF1α or PGK1 decelerated JMJD1A-enhanced UBC cell growth. Consistent with these results, a positive correlation between JMJD1A and several key glycolytic genes in human UBC samples was established by analyzing a microarray-based gene expression profile. In conclusion, our study demonstrates that JMJD1A promotes UBC progression by enhancing glycolysis through coactivation of HIF1α, implicating that JMJD1A is a potential molecular target for UBC treatment.

  20. Factors regulated by interferon gamma and hypoxia-inducible factor 1A contribute to responses that protect mice from Coccidioides immitis infection

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    2012-01-01

    Background Coccidioidomycosis results from airborne infections caused by either Coccidioides immitis or C. posadasii. Both are pathogenic fungi that live in desert soil in the New World and can infect normal hosts, but most infections are self-limited. Disseminated infections occur in approximately 5% of cases and may prove fatal. Mouse models of the disease have identified strains that are resistant (e.g. DBA/2) or susceptible (e.g. C57BL/6) to these pathogens. However, the genetic and immunological basis for this difference has not been fully characterized. Results Microarray technology was used to identify genes that were differentially expressed in lung tissue between resistant DBA/2 and sensitive C57BL/6 mice after infection with C. immitis. Differentially expressed genes were mapped onto biological pathways, gene ontologies, and protein interaction networks, which revealed that innate immune responses mediated by Type II interferon (i.e., IFNG) and the signal transducer and activator of transcription 1 (STAT1) contribute to the resistant phenotype. In addition, upregulation of hypoxia inducible factor 1A (HIF1A), possibly as part of a larger inflammatory response mediated by tumor necrosis factor alpha (TNFA), may also contribute to resistance. Microarray gene expression was confirmed by real-time quantitative PCR for a subset of 12 genes, which revealed that IFNG HIF1A and TNFA, among others, were significantly differentially expressed between the two strains at day 14 post-infection. Conclusion These results confirm the finding that DBA/2 mice express more Type II interferon and interferon stimulated genes than genetically susceptible strains and suggest that differential expression of HIF1A may also play a role in protection. PMID:23006927

  1. Factors regulated by interferon gamma and hypoxia-inducible factor 1A contribute to responses that protect mice from Coccidioides immitis infection

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    Woelk Christopher H

    2012-09-01

    Full Text Available Abstract Background Coccidioidomycosis results from airborne infections caused by either Coccidioides immitis or C. posadasii. Both are pathogenic fungi that live in desert soil in the New World and can infect normal hosts, but most infections are self-limited. Disseminated infections occur in approximately 5% of cases and may prove fatal. Mouse models of the disease have identified strains that are resistant (e.g. DBA/2 or susceptible (e.g. C57BL/6 to these pathogens. However, the genetic and immunological basis for this difference has not been fully characterized. Results Microarray technology was used to identify genes that were differentially expressed in lung tissue between resistant DBA/2 and sensitive C57BL/6 mice after infection with C. immitis. Differentially expressed genes were mapped onto biological pathways, gene ontologies, and protein interaction networks, which revealed that innate immune responses mediated by Type II interferon (i.e., IFNG and the signal transducer and activator of transcription 1 (STAT1 contribute to the resistant phenotype. In addition, upregulation of hypoxia inducible factor 1A (HIF1A, possibly as part of a larger inflammatory response mediated by tumor necrosis factor alpha (TNFA, may also contribute to resistance. Microarray gene expression was confirmed by real-time quantitative PCR for a subset of 12 genes, which revealed that IFNG HIF1A and TNFA, among others, were significantly differentially expressed between the two strains at day 14 post-infection. Conclusion These results confirm the finding that DBA/2 mice express more Type II interferon and interferon stimulated genes than genetically susceptible strains and suggest that differential expression of HIF1A may also play a role in protection.

  2. Factors regulated by interferon gamma and hypoxia-inducible factor 1A contribute to responses that protect mice from Coccidioides immitis infection.

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    Woelk, Christopher H; Zhang, Jin X; Walls, Lorraine; Viriyakosol, Suganya; Singhania, Akul; Kirkland, Theo N; Fierer, Joshua

    2012-09-24

    Coccidioidomycosis results from airborne infections caused by either Coccidioides immitis or C. posadasii. Both are pathogenic fungi that live in desert soil in the New World and can infect normal hosts, but most infections are self-limited. Disseminated infections occur in approximately 5% of cases and may prove fatal. Mouse models of the disease have identified strains that are resistant (e.g. DBA/2) or susceptible (e.g. C57BL/6) to these pathogens. However, the genetic and immunological basis for this difference has not been fully characterized. Microarray technology was used to identify genes that were differentially expressed in lung tissue between resistant DBA/2 and sensitive C57BL/6 mice after infection with C. immitis. Differentially expressed genes were mapped onto biological pathways, gene ontologies, and protein interaction networks, which revealed that innate immune responses mediated by Type II interferon (i.e., IFNG) and the signal transducer and activator of transcription 1 (STAT1) contribute to the resistant phenotype. In addition, upregulation of hypoxia inducible factor 1A (HIF1A), possibly as part of a larger inflammatory response mediated by tumor necrosis factor alpha (TNFA), may also contribute to resistance. Microarray gene expression was confirmed by real-time quantitative PCR for a subset of 12 genes, which revealed that IFNG HIF1A and TNFA, among others, were significantly differentially expressed between the two strains at day 14 post-infection. These results confirm the finding that DBA/2 mice express more Type II interferon and interferon stimulated genes than genetically susceptible strains and suggest that differential expression of HIF1A may also play a role in protection.

  3. Heterogeneity in Pseudomonas aeruginosa Biofilms Includes Expression of Ribosome Hibernation Factors in the Antibiotic-Tolerant Subpopulation and Hypoxia-Induced Stress Response in the Metabolically Active Population

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    Williamson, Kerry S.; Richards, Lee A.; Perez-Osorio, Ailyn C.; Pitts, Betsey; McInnerney, Kathleen; Stewart, Philip S.

    2012-01-01

    Bacteria growing in biofilms are physiologically heterogeneous, due in part to their adaptation to local environmental conditions. Here, we characterized the local transcriptome responses of Pseudomonas aeruginosa growing in biofilms by using a microarray analysis of isolated biofilm subpopulations. The results demonstrated that cells at the top of the biofilms had high mRNA abundances for genes involved in general metabolic functions, while mRNA levels for these housekeeping genes were low in cells at the bottom of the biofilms. Selective green fluorescent protein (GFP) labeling showed that cells at the top of the biofilm were actively dividing. However, the dividing cells had high mRNA levels for genes regulated by the hypoxia-induced regulator Anr. Slow-growing cells deep in the biofilms had little expression of Anr-regulated genes and may have experienced long-term anoxia. Transcripts for ribosomal proteins were associated primarily with the metabolically active cell fraction, while ribosomal RNAs were abundant throughout the biofilms, indicating that ribosomes are stably maintained even in slowly growing cells. Consistent with these results was the identification of mRNAs for ribosome hibernation factors (the rmf and PA4463 genes) at the bottom of the biofilms. The dormant biofilm cells of a P. aeruginosa Δrmf strain had decreased membrane integrity, as shown by propidium iodide staining. Using selective GFP labeling and cell sorting, we show that the dividing cells are more susceptible to killing by tobramycin and ciprofloxacin. The results demonstrate that in thick P. aeruginosa biofilms, cells are physiologically distinct spatially, with cells deep in the biofilm in a viable but antibiotic-tolerant slow-growth state. PMID:22343293

  4. Prolyl hydroxylase 2 dependent and Von-Hippel-Lindau independent degradation of Hypoxia-inducible factor 1 and 2 alpha by selenium in clear cell renal cell carcinoma leads to tumor growth inhibition

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    Chintala Sreenivasulu

    2012-07-01

    Full Text Available Abstract Background Clear cell renal cell carcinoma (ccRCC accounts for more than 80% of the cases of renal cell carcinoma. In ccRCC deactivation of Von-Hippel-Lindau (VHL gene contributes to the constitutive expression of hypoxia inducible factors 1 and 2 alpha (HIF-α, transcriptional regulators of several genes involved in tumor angiogenesis, glycolysis and drug resistance. We have demonstrated inhibition of HIF-1α by Se-Methylselenocysteine (MSC via stabilization of prolyl hydroxylases 2 and 3 (PHDs and a significant therapeutic synergy when combined with chemotherapy. This study was initiated to investigate the expression of PHDs, HIF-α, and VEGF-A in selected solid cancers, the mechanism of HIF-α inhibition by MSC, and to document antitumor activity of MSC against human ccRCC xenografts. Methods Tissue microarrays of primary human cancer specimens (ccRCC, head & neck and colon were utilized to determine the incidence of PHD2/3, HIF-α, and VEGF-A by immunohistochemical methods. To investigate the mechanism(s of HIF-α inhibition by MSC, VHL mutated ccRCC cells RC2 (HIF-1α positive, 786–0 (HIF-2α positive and VHL wild type head & neck cancer cells FaDu (HIF-1α were utilized. PHD2 and VHL gene specific siRNA knockdown and inhibitors of PHD2 and proteasome were used to determine their role in the degradation of HIF-1α by MSC. Results We have demonstrated that ccRCC cells express low incidence of PHD2 (32%, undetectable PHD3, high incidence of HIF-α (92%, and low incidence of VEGF-A compared to head & neck and colon cancers. This laboratory was the first to identify MSC as a highly effective inhibitor of constitutively expressed HIF-α in ccRCC tumors. MSC did not inhibit HIF-1α protein synthesis, but facilitated its degradation. The use of gene knockdown and specific inhibitors confirmed that the inhibition of HIF-1α was PHD2 and proteasome dependent and VHL independent. The effects of MSC treatment on HIF-α were associated with

  5. Hypoxia-inducible factor 1 alpha is a poor prognostic factor and potential therapeutic target in malignant peripheral nerve sheath tumor.

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    Suguru Fukushima

    Full Text Available Malignant peripheral nerve sheath tumor (MPNST is a rare soft tissue sarcoma with poor prognosis. Hypoxia-inducible factor 1 (HIF-1 plays a crucial role in the cellular response to hypoxia and regulates the expression of multiple genes involved in tumor progression in various cancers. However, the importance of the expression of HIF-1α in MPNSTs is unclear.The expression of HIF-1α was examined immunohistochemically in 82 MPNST specimens. Cell culture assays of human MPNST cells under normoxic and hypoxic conditions were used to evaluate the impact of anti-HIF-1α-specific siRNA inhibition on cell survival. A screening kit was employed to identify small molecules that inhibited HIF-1α.The nuclear expression of HIF-1α was positive in 75.6% of MPNST samples (62/82 cases. Positivity for HIF-1α was a significant poor prognostic factor both in univariate (P = 0.048 and multivariate (P ≤ 0.0001 analyses. HIF-1α knockdown abrogated MPNST cell growth, inducing apoptosis. Finally, chetomin, an inhibitor of HIF-1α, effectively inhibited the growth of MPNST cells and induced their apoptosis.Inhibition of HIF-1α signaling is a potential treatment option for MPNSTs.

  6. Hypoxia Inducible Factor 1-Alpha (HIF-1 Alpha) Is Induced during Reperfusion after Renal Ischemia and Is Critical for Proximal Tubule Cell Survival

    Science.gov (United States)

    Blanco-Sánchez, Ignacio; Sáenz-Morales, David; Aguado-Fraile, Elia; Ponte, Belén; Ramos, Edurne; Sáiz, Ana; Jiménez, Carlos; Ordoñez, Angel; López-Cabrera, Manuel; del Peso, Luis; de Landázuri, Manuel O.; Liaño, Fernando; Selgas, Rafael; Sanchez-Tomero, Jose Antonio; García-Bermejo, María Laura

    2012-01-01

    Acute tubular necrosis (ATN) caused by ischemia/reperfusion (I/R) during renal transplantation delays allograft function. Identification of factors that mediate protection and/or epithelium recovery could help to improve graft outcome. We studied the expression, regulation and role of hypoxia inducible factor 1-alpha (HIF-1 α), using in vitro and in vivo experimental models of I/R as well as human post-transplant renal biopsies. We found that HIF-1 α is stabilized in proximal tubule cells during ischemia and unexpectedly in late reperfusion, when oxygen tension is normal. Both inductions lead to gene expression in vitro and in vivo. In vitro interference of HIF-1 α promoted cell death and in vivo interference exacerbated tissue damage and renal dysfunction. In pos-transplant human biopsies, HIF-1 α was expressed only in proximal tubules which exhibited normal renal structure with a significant negative correlation with ATN grade. In summary, using experimental models and human biopsies, we identified a novel HIF-1 α induction during reperfusion with a potential critical role in renal transplant. PMID:22432008

  7. A novel role for 3, 4-dichloropropionanilide (DCPA in the inhibition of prostate cancer cell migration, proliferation, and hypoxia-inducible factor 1alpha expression

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    Schafer Rosana

    2006-08-01

    Full Text Available Abstract Background The amide class compound, 3, 4-dichloropropionanilide (DCPA is known to affect multiple signaling pathways in lymphocyte and macrophage including the inhibition of NF-κB ability. However, little is known about the effect of DCPA in cancer cells. Hypoxia-inducible factor 1 (HIF-1 regulates the expression of many genes including vascular endothelial growth factor (VEGF, heme oxygenase 1, inducible nitric oxide synthase, aldolase, enolase, and lactate dehydrogenase A. HIF-1 expression is associated with tumorigenesis and angiogenesis. Methods We used Transwell assay to study cell migration, and used immunoblotting to study specific protein expression in the cells. Results In this report, we demonstrate that DCPA inhibited the migration and proliferation of DU145 and PC-3 prostate cancer cells induced by serum, insulin, and insulin-like growth factor I (IGF-I. We found that DCPA inhibited HIF-1 expression in a subunit-specific manner in these cancer cell lines induced by serum and growth factors, and decreased HIF-1α expression by affecting its protein stability. Conclusion DCPA can inhibit prostate cancer cell migration, proliferation, and HIF-1α expression, suggesting that DCPA could be potentially used for therapeutic purpose for prostate cancer in the future.

  8. Silencing of eIF3e promotes blood perfusion recovery after limb ischemia through stabilization of hypoxia-inducible factor 2α activity.

    Science.gov (United States)

    Hashimoto, Takuya; Chen, Li; Kimura, Hideo; Endler, Alexander; Koyama, Hiroyuki; Miyata, Tetsuro; Shibasaki, Futoshi; Watanabe, Toshiaki

    2016-07-01

    We previously observed that silencing of eukaryotic translation initiation factor 3 subunit e (eIF3e), a hypoxia-independent downregulator of hypoxia-inducible factor 2α (HIF-2α), led to neoangiogenesis by promoting HIF-2α activity under normoxic conditions. In the current study, we investigated whether temporary silencing of eIF3e in muscles affects blood flow recovery in a mouse ischemic limb model. eIF3e silencing was performed using small interfering RNA (siRNA), and changes in gene transcription and protein expression were analyzed in vitro using murine primary skeletal muscle myoblast and human primary skeletal muscle myoblast cell cultures. In unilateral femoral artery ligation experiments, eIF3e siRNA-expressing plasmids were injected into the muscles of BALB/c mice near the ligation sites, and tissue damage and loss of limb function were scored for 28 days while serial measurements of limb perfusions were performed with laser Doppler perfusion imaging. Silencing of eIF3e in murine primary skeletal muscle myoblasts led to stabilization of HIF-2α and upregulation of angiogenic transcripts, including basic fibroblast growth factor and platelet-derived growth factor B (P recovery at days 7, 14, and 21 (P < .05). eIF3e is an angiogenesis suppressor and may be a therapeutic target for promoting angiogenesis after ischemic injuries. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  9. Hypoxia inducible factor 1-alpha (HIF-1 alpha is induced during reperfusion after renal ischemia and is critical for proximal tubule cell survival.

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    Elisa Conde

    Full Text Available Acute tubular necrosis (ATN caused by ischemia/reperfusion (I/R during renal transplantation delays allograft function. Identification of factors that mediate protection and/or epithelium recovery could help to improve graft outcome. We studied the expression, regulation and role of hypoxia inducible factor 1-alpha (HIF-1 α, using in vitro and in vivo experimental models of I/R as well as human post-transplant renal biopsies. We found that HIF-1 α is stabilized in proximal tubule cells during ischemia and unexpectedly in late reperfusion, when oxygen tension is normal. Both inductions lead to gene expression in vitro and in vivo. In vitro interference of HIF-1 α promoted cell death and in vivo interference exacerbated tissue damage and renal dysfunction. In pos-transplant human biopsies, HIF-1 α was expressed only in proximal tubules which exhibited normal renal structure with a significant negative correlation with ATN grade. In summary, using experimental models and human biopsies, we identified a novel HIF-1 α induction during reperfusion with a potential critical role in renal transplant.

  10. Molecular characterization of mudskipper (Boleophthalmus pectinirostris) hypoxia-inducible factor-1α (HIF-1α) and analysis of its function in monocytes/macrophages

    Science.gov (United States)

    Li, Chang-Hong; Chen, Jiong

    2017-01-01

    Hypoxia-inducible factor-1α (HIF-1α) plays a critical role in immune and inflammatory responses and is important in controlling a variety of processes in monocytes and macrophages. However, very little information is available about the functions of HIF-1α in fish monocytes/macrophages (MO/MФ). In this study, the cDNA sequence of the mudskipper (Boleophthalmus pectinirostris) HIF-1α gene (BpHIF-1α) was determined. Sequence comparison and phylogenetic tree analysis showed that BpHIF-1α is clustered in the fish HIF-1α tree. Constitutive expression of BpHIF-1α mRNA was detected by real-time quantitative PCR in all tested tissues, and the expression was found to be dramatically increased in the skin, liver, spleen, and kidney after Edwardsiella tarda infection. In addition, hypoxia and infection induced the expression of the BpHIF-1α transcript and protein in MO/MФ, respectively. Hypoxia caused an increase in phagocytic and bactericidal capacity of mudskipper MO/MФ in a BpHIF-1α-dependent manner. BpHIF-1α induced an anti-inflammatory status in MO/MФ upon E. tarda infection and hypoxia. Therefore, BpHIF-1α may play a predominant role in the modulation of mudskipper MO/MФ function in the innate immune system. PMID:28542591

  11. A hypoxia-inducible factor (HIF)-3α splicing variant, HIF-3α4 impairs angiogenesis in hypervascular malignant meningiomas with epigenetically silenced HIF-3α4

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    Ando, Hitoshi [Department of Neurosurgery, Nagoya University School of Medicine, Nagoya (Japan); Department of Neurosurgery, Fukushima Medical University School of Medicine, Fukushima (Japan); Natsume, Atsushi, E-mail: anatsume@med.nagoya-u.ac.jp [Department of Neurosurgery, Nagoya University School of Medicine, Nagoya (Japan); Iwami, Kenichiro; Ohka, Fumiharu [Department of Neurosurgery, Nagoya University School of Medicine, Nagoya (Japan); Kuchimaru, Takahiro; Kizaka-Kondoh, Shinae [Department of Biomolecular Engineering, Tokyo Institute of Technology Graduate School of Bioscience and Biotechnology, Yokohama (Japan); Ito, Kengo [National Center for Geriatrics and Gerontology, Aichi (Japan); Saito, Kiyoshi [Department of Neurosurgery, Fukushima Medical University School of Medicine, Fukushima (Japan); Sugita, Sachi; Hoshino, Tsuneyoshi [MICRON Inc.Medical Facilities Support Department, Aichi (Japan); Wakabayashi, Toshihiko [Department of Neurosurgery, Nagoya University School of Medicine, Nagoya (Japan)

    2013-03-29

    Highlights: ► HIF-3α4 is silenced by DNA methylation in meningiomas. ► Induction of HIF-3α4 impaired angiogenesis in meningiomas. ► Induction of HIF-3α4 impaired proliferation and oxygen-dependent metabolism. -- Abstract: Hypoxia inducible factor is a dominant regulator of adaptive cellular responses to hypoxia and controls the expression of a large number of genes regulating angiogenesis as well as metabolism, cell survival, apoptosis, and other cellular functions in an oxygen level-dependent manner. When a neoplasm is able to induce angiogenesis, tumor progression occurs more rapidly because of the nutrients provided by the neovasculature. Meningioma is one of the most hypervascular brain tumors, making anti-angiogenic therapy an attractive novel therapy for these tumors. HIF-3α has been conventionally regarded as a dominant-negative regulator of HIF-1α, and although alternative HIF-3α splicing variants are extensively reported, their specific functions have not yet been determined. In this study, we found that the transcription of HIF-3α4 was silenced by the promoter DNA methylation in meningiomas, and inducible HIF-3α4 impaired angiogenesis, proliferation, and metabolism/oxidation in hypervascular meningiomas. Thus, HIF-3α4 could be a potential molecular target in meningiomas.

  12. Hypoxia-Inducible Factor-1α: A Potential Factor for the Enhancement of Osseointegration between Dental Implants and Tissue-Engineered Bone

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    Duohong Zou

    2011-07-01

    Full Text Available Introduction: Tissue-engineered bones are widely utilized to protect healthy tissue, reduce pain, and increase the success rate of dental implants. one of the most challenging obstacles lies in obtaining effective os-seointegration between dental implants and tissue-engineered structures. Deficiencies in vascularization, osteogenic factors, oxygen, and other nutrients inside the tissue-engineered bone during the early stages following implantation all inhibit effective osseointe-gration. Oxygen is required for aerobic metabolism in bone and blood vessel tissues, but oxygen levels inside tissue-engineered bone are not suf-ficient for cell proliferation. HIF-1α is a pivotal regulator of hypoxic and ischemic vascular responses, driving transcriptional activation of hundreds of genes involved in vascular reactivity, angiogenesis, arteriogenesis, and osteogenesis.The hypothesis: Hypoxia-Inducible Factor-1α seems a potential factor for the enhancement of osseointegration between dental implants and tissue-engineered bone.Evaluation of the hypothesis: Enhancement of HIF-1α protein expression is recognized as the most promising approach for angiogenesis, because it can induce multiple angiogenic targets in a coordinated manner. Therefore, it will be a novel potential therapeutic methods targeting HIF-1α expression to enhance osseointegration be-tween dental implants and tissue-engineered bone.

  13. Hypoxia-induced nitric oxide production and tumour perfusion is inhibited by pegylated arginine deiminase (ADI-PEG20).

    Science.gov (United States)

    Burrows, Natalie; Cane, Gaelle; Robson, Mathew; Gaude, Edoardo; Howat, William J; Szlosarek, Peter W; Pedley, R Barbara; Frezza, Christian; Ashcroft, Margaret; Maxwell, Patrick H

    2016-03-14

    The hypoxic tumour microenvironment represents an aggressive, therapy-resistant compartment. As arginine is required for specific hypoxia-induced processes, we hypothesised that arginine-deprivation therapy may be useful in targeting hypoxic cancer cells. We explored the effects of the arginine-degrading agent ADI-PEG20 on hypoxia-inducible factor (HIF) activation, the hypoxia-induced nitric oxide (NO) pathway and proliferation using HCT116 and UMUC3 cells and xenografts. The latter lack argininosuccinate synthetase (ASS1) making them auxotrophic for arginine. In HCT116 cells, ADI-PEG20 inhibited hypoxic-activation of HIF-1α and HIF-2α, leading to decreased inducible-nitric oxide synthase (iNOS), NO-production, and VEGF. Interestingly, combining hypoxia and ADI-PEG20 synergistically inhibited ASS1. ADI-PEG20 inhibited mTORC1 and activated the unfolded protein response providing a mechanism for inhibition of HIF and ASS1. ADI-PEG20 inhibited tumour growth, impaired hypoxia-associated NO-production, and decreased vascular perfusion. Expression of HIF-1α/HIF-2α/iNOS and VEGF were reduced, despite an increased hypoxic tumour fraction. Similar effects were observed in UMUC3 xenografts. In summary, ADI-PEG20 inhibits HIF-activated processes in two tumour models with widely different arginine biology. Thus, ADI-PEG20 may be useful in the clinic to target therapy-resistant hypoxic cells in ASS1-proficient tumours and ASS1-deficient tumours.

  14. The hypoxia-induced facilitation of augmented breaths is suppressed by the common effect of carbonic anhydrase inhibition.

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    Bell, Harold J; Haouzi, Philippe

    2010-05-31

    The typical respiratory response to hypoxia includes a dramatic facilitation of augmented breaths (ABs) or 'sighs' in the breathing rhythm. We recently found that when acetazolamide treatment is used to promote CO(2) retention and counteract alkalosis during exposure to hypoxia, then the hypoxia-induced facilitation of ABs is effectively prevented. These results indicate that hyperventilation-induced hypocapnia/alkalosis is an essential factor involved in the hypoxia-induced facilitation of augmented breaths. However, acetazolamide is also known to decrease the sensitivity of the arterial chemoreceptors. Therefore, the question remains as to whether acetazolamide prevents the facilitation of ABs during hypoxia by offsetting the effects of respiratory alkalosis, or alternatively by suppressing carotid body afferent activity. In the present study, we addressed this question by studying the effects of treatment with an alternative carbonic anhydrase inhibitor, methazolamide, which has been reported to leave carotid body responsiveness to hypoxia intact. Respiratory variables were monitored before, during and after 2 days of methazolamide treatment (10 mg kg(-1) IP, bid) in unsedated and unrestrained adult male rats. Pre-treatment, the number of ABs observed in a 5 min observation window was 1.2 + or - 0.8 and 17.4 + or - 3.8 in room air and hypoxia, respectively. During methazolamide treatment, the facilitation of ABs in hypoxia was rapidly and reversibly suppressed such that ABs we no longer significantly more frequent than they were in room air. The present results demonstrate that the hypoxia-induced facilitation of ABs can be suppressed via the general effects of carbonic anhydrase inhibition, which are common to both acetazolamide and methazolamide. We discuss these results as they pertain to the mechanisms regulating augmented breath production, and the possible association between hypocapnia/alkalosis and sleep disordered breathing. Copyright 2010 Elsevier B

  15. Proteomic analysis reveals that proteasome subunit beta 6 is involved in hypoxia-induced pulmonary vascular remodeling in rats.

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    Jian Wang

    Full Text Available Chronic hypoxia (CH is known to be one of the major causes of pulmonary hypertension (PH, which is characterized by sustained elevation of pulmonary vascular resistance resulting from vascular remodeling. In this study, we investigated whether the ubiquitin proteasome system (UPS was involved in the mechanism of hypoxia-induced pulmonary vascular remodeling. We isolated the distal pulmonary artery (PA from a previously defined chronic hypoxic pulmonary hypertension (CHPH rat model, performed proteomic analyses in search of differentially expressed proteins belonging to the UPS, and subsequently identified their roles in arterial remodeling.Twenty-two proteins were differently expressed between the CH and normoxic group. Among them, the expression of proteasome subunit beta (PSMB 1 and PSMB6 increased after CH exposure. Given that PSMB1 is a well-known structural subunit and PSMB6 is a functional subunit, we sought to assess whether PSMB6 could be related to the multiple functional changes during the CHPH process. We confirmed the proteomic results by real-time PCR and Western blot. With the increase in quantity of the active subunit, proteasome activity in both cultured pulmonary artery smooth muscle cells (PASMCs and isolated PA from the hypoxic group increased. An MTT assay revealed that the proteasome inhibitor MG132 was able to attenuate the hypoxia-induced proliferation of PASMC in a dose-dependent manner. Knockdown of PSMB6 using siRNA also prevented hypoxia-induced proliferation.The present study revealed the association between increased PSMB6 and CHPH. CH up-regulated proteasome activity and the proliferation of PASMCs, which may have been related to increased PSMB6 expression and the subsequently enhanced functional catalytic sites of the proteasome. These results suggested an essential role of the proteasome during CHPH development, a novel finding requiring further study.

  16. TanshinoneIIA and cryptotanshinone protect against hypoxia-induced mitochondrial apoptosis in H9c2 cells.

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    Hyou-Ju Jin

    Full Text Available Mitochondrial apoptosis pathway is an important target of cardioprotective signalling. Tanshinones, a group of major bioactive compounds isolated from Salvia miltiorrhiza, have been reported with actions against inflammation, oxidative stress, and myocardial ischemia reperfusion injury. However, the actions of these compounds on the chronic hypoxia-related mitochondrial apoptosis pathway have not been investigated. In this study, we examined the effects and molecular mechanisms of two major tanshonones, tanshinone IIA (TIIA and cryptotanshinone (CT on hypoxia induced apoptosis in H9c2 cells. Cultured H9c2 cells were treated with TIIA and CT (0.3 and 3 μΜ 2 hr before and during an 8 hr hypoxic period. Chronic hypoxia caused a significant increase in hypoxia inducible factor 1α expression and the cell late apoptosis rate, which was accompanied with an increase in caspase 3 activity, cytochrome c release, mitochondria membrane potential and expression of pro-apoptosis proteins (Bax and Bak. TIIA and CT (0.3 and 3 μΜ, in concentrations without affecting the cell viability, significantly inhibited the late apoptosis and the changes of caspase 3 activity, cytochrome c release, and mitochondria membrane potential induced by chronic hypoxia. These compounds also suppressed the overexpression of Bax and reduced the ratio of Bax/Bcl-2. The results indicate that TIIA and CT protect against chronic hypoxia induced cell apoptosis by regulating the mitochondrial apoptosis signaling pathway, involving inhibitions of mitochondria hyperpolarization, cytochrome c release and caspase 3 activity, and balancing anti- and pro-apoptotic proteins in Bcl-2 family proteins.

  17. Reducing TRPC1 Expression through Liposome-Mediated siRNA Delivery Markedly Attenuates Hypoxia-Induced Pulmonary Arterial Hypertension in a Murine Model

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    Cheuk-Kwan Sun

    2014-01-01

    Full Text Available We tested the hypothesis that Lipofectamine siRNA delivery to deplete transient receptor potential cation channel (TRPC 1 protein expression can suppress hypoxia-induced pulmonary arterial hypertension (PAH in mice. Adult male C57BL/6 mice were equally divided into group 1 (normal controls, group 2 (hypoxia, and group 3 (hypoxia + siRNA TRPC1. By day 28, right ventricular systolic pressure (RVSP, number of muscularized arteries, right ventricle (RV, and lung weights were increased in group 2 than in group 1 and reduced in group 3 compared with group 2. Pulmonary crowded score showed similar pattern, whereas number of alveolar sacs exhibited an opposite pattern compared to that of RVSP in all groups. Protein expressions of TRPCs, HIF-1α, Ku-70, apoptosis, and fibrosis and pulmonary mRNA expressions of inflammatory markers were similar pattern, whereas protein expressions of antifibrosis and VEGF were opposite to the pattern of RVSP. Cellular markers of pulmonary DNA damage, repair, and smooth muscle proliferation exhibited a pattern similar to that of RVSP. The mRNA expressions of proapoptotic and hypertrophy biomarkers displayed a similar pattern, whereas sarcomere length showed an opposite pattern compared to that of RVSP in all groups. Lipofectamine siRNA delivery effectively reduced TRPC1 expression, thereby attenuating PAH-associated RV and pulmonary arteriolar remodeling.

  18. Retraction: Genistein protects genioglossus myocyte against hypoxia-induced injury through PI3K-Akt and ERK MAPK pathways.

    Science.gov (United States)

    2012-05-01

    RETRACTION: The following article from Journal of Cellular Biochemistry, Genistein protects genioglossus myocyte against hypoxia-induced injury through PI3K-Akt and ERK MAPK pathways by Wanghui Ding and Yuehua Liu, posted online on May 19, 2011 in Wiley Online Library (onlinelibrary.wiley.com), has been retracted by agreement between the authors, the journal Editor in Chief, Dr. Gary S. Stein and Wiley-Liss, Inc. The retraction has been made as authorization to publish was not granted by one of the funding bodies. Copyright © 2012 Wiley Periodicals, Inc.

  19. SurR9C84A protects and recovers human cardiomyocytes from hypoxia induced apoptosis

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    Ashok, Ajay [Nanomedicine-Laboratory of Immunology and Molecular Biomedical Research (NLIMBR), School of Medicine (SoM), Faculty of Health, Centre for Molecular and Medical Research - C-MMR, Deakin University, Waurn Ponds, Victoria 3216 (Australia); Department of Pathology, Case Western Reserve University, 2103 Cornell Rd. WRB 5128, Cleveland, OH 44106-7288 (United States); Kanwar, Jagat Rakesh [Nanomedicine-Laboratory of Immunology and Molecular Biomedical Research (NLIMBR), School of Medicine (SoM), Faculty of Health, Centre for Molecular and Medical Research - C-MMR, Deakin University, Waurn Ponds, Victoria 3216 (Australia); Krishnan, Uma Maheswari [Centre for Nanotechnology & Advanced Biomaterials (CeNTAB), School of Chemical & Biotechnology (SCBT), SASTRA University, Thanjavur 613401 (India); Kanwar, Rupinder Kaur, E-mail: rupinder.kanwar@deakin.edu.au [Nanomedicine-Laboratory of Immunology and Molecular Biomedical Research (NLIMBR), School of Medicine (SoM), Faculty of Health, Centre for Molecular and Medical Research - C-MMR, Deakin University, Waurn Ponds, Victoria 3216 (Australia)

    2017-01-01

    Survivin, as an anti-apoptotic protein and a cell cycle regulator, is recently gaining importance for its regenerative potential in salvaging injured hypoxic cells of vital organs such as heart. Different strategies are being employed to upregulate survivin expression in dying hypoxic cardiomyocytes. We investigated the cardioprotective potential of a cell permeable survivin mutant protein SurR9C84A, for the management of hypoxia mediated cardiomyocyte apoptosis, in a novel and clinically relevant model employing primary human cardiomyocytes (HCM). The aim of this research work was to study the efficacy and mechanism of SurR9C84A facilitated cardioprotection and regeneration in hypoxic HCM. To mimic hypoxic microenvironment in vitro, well characterized HCM were treated with 100 µm (48 h) cobalt chloride to induce hypoxia. Hypoxia induced (HI) HCM were further treated with SurR9C84A (1 µg/mL) in order to analyse its cardioprotective efficacy. Confocal microscopy showed rapid internalization of SurR9C84A and scanning electron microscopy revealed the reinstatement of cytoskeleton projections in HI HCM. SurR9C84A treatment increased cell viability, reduced cell death via, apoptosis (Annexin-V assay), and downregulated free cardiac troponin T and MMP-9 expression. SurR9C84A also upregulated the expression of proliferation markers (PCNA and Ki-67) and downregulated mitochondrial depolarization and ROS levels thereby, impeding cell death. Human Apoptosis Array further revealed that SurR9C84A downregulated expression of pro-apoptotic markers and augmented expression of HSPs and HTRA2/Omi. SurR9C84A treatment led to enhanced levels of survivin, VEGF, PI3K and pAkt. SurR9C84A proved non-toxic to normoxic HCM, as validated through unaltered cell proliferation and other marker levels. Its pre-treatment exhibited lesser susceptibility to hypoxia/damage. SurR9C84A holds a promising clinical potential for human cardiomyocyte survival and proliferation following hypoxic injury

  20. Prognostic role of hypoxia-inducible factor-1 alpha expression in osteosarcoma: a meta-analysis

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    Ren HY

    2016-03-01

    Full Text Available Hai-Yong Ren,1 Yin-Hua Zhang,1,2 Heng-Yuan Li,1 Tao Xie,1 Ling-Ling Sun,1 Ting Zhu,1 Sheng-Dong Wang,1 Zhao-Ming Ye1 1Department of Orthopaedics, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 2The First Department of Orthopaedics, Hospital of Zhejiang General Corps of Armed Police Forces, Jiaxing, People’s Republic of China Background: Hypoxia-inducible factor-1α (HIF-1α plays an important role in tumor progression and metastasis. A number of studies have investigated the association of HIF-1α with prognosis and clinicopathological characteristics of osteosarcoma but yielded inconsistent results.  Method: Systematic computerized searches were performed in PubMed, Embase, and Web of Science databases for relevant original articles. The pooled hazard ratios (HRs and odds ratios (ORs with corresponding confidence intervals (CIs were calculated to assess the prognostic value of HIF-1α expression. The standard mean difference was used to analyze the continuous variable.  Results: Finally, nine studies comprising 486 patients were subjected to final analysis. Protein expression level of HIF-1α was found to be significantly related to overall survival (HR =3.0; 95% CI: 1.46–6.15, disease-free survival (HR =2.23; 95% CI: 1.26–3.92, pathologic grade (OR =21.33; 95% CI: 4.60–98.88, tumor stage (OR =10.29; 95% CI: 3.55–29.82, chemotherapy response (OR =9.68; 95% CI: 1.87–50.18, metastasis (OR =5.06; 95% CI: 2.87–8.92, and microvessel density (standard mean difference =2.83; 95% CI: 2.28–3.39.  Conclusion: This meta-analysis revealed that overexpression of HIF-1α is a predictive factor of poor outcomes for osteosarcoma. HIF-1α appeared to play an important role in prognostic evaluation and may be a potential target in antitumoral therapy. Keywords: HIF-1α, osteosarcoma, prognosis, meta-analysis

  1. Prolonged fasting activates hypoxia inducible factors-1α, -2α and -3α in a tissue-specific manner in northern elephant seal pups.

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    Soñanez-Organis, José G; Vázquez-Medina, José P; Crocker, Daniel E; Ortiz, Rudy M

    2013-09-10

    Hypoxia inducible factors (HIFs) are important regulators of energy homeostasis and cellular adaptation to low oxygen conditions. Northern elephant seals are naturally adapted to prolonged periods (1-2 months) of food deprivation (fasting) which result in metabolic changes that may activate HIF-1. However, the effects of prolonged fasting on HIFs are not well defined. We obtained the full-length cDNAs of HIF-1α and HIF-2α, and partial cDNA of HIF-3α in northern elephant seal pups. We also measured mRNA and nuclear protein content of HIF-1α, -2α, -3α in muscle and adipose during prolonged fasting (1, 3, 5 & 7 weeks), along with mRNA expression of HIF-mediated genes, LDH and VEGF. HIF-1α, -2α and -3α are 2595, 2852 and 1842 bp and encode proteins of 823, 864 and 586 amino acid residues with conserved domains needed for their function (bHLH and PAS) and regulation (ODD and TAD). HIF-1α and -2α mRNA expression increased 3- to 5-fold after 7 weeks of fasting in adipose and muscle, whereas HIF-3α increased 5-fold after 7 weeks of fasting in adipose. HIF-2α protein expression was detected in nuclear fractions from adipose and muscle, increasing approximately 2-fold, respectively with fasting. Expression of VEGF increased 3-fold after 7 weeks in adipose and muscle, whereas LDH mRNA expression increased 12-fold after 7 weeks in adipose. While the 3 HIFα genes are expressed in muscle and adipose, only HIF-2α protein was detectable in the nucleus suggesting that HIF-2α may contribute more significantly in the up-regulation of genes involved in the metabolic adaptation during fasting in the elephant seal. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Morphological and functional alterations of the ductus arteriosus in a chicken model of hypoxia-induced fetal growth retardation.

    Science.gov (United States)

    Van der Sterren, Saskia; Agren, Pia; Zoer, Bea; Kessels, Lilian; Blanco, Carlos E; Villamor, Eduardo

    2009-03-01

    The hypoxic conditions in which children with intrauterine growth retardation (IUGR) develop are hypothesized to alter the development of the ductus arteriosus (DA). We aimed to evaluate the effects of in ovo hypoxia on chicken DA morphometry and reactivity. Hypoxia (15% O2 from day 6 to 19 of the 21-d incubation period) produced a reduction in the body mass of the 19-d fetuses and a shortening of right and left DAs. However, ductal lumen and media cross-sectional areas were not affected by hypoxia. The ductal contractions induced by oxygen, KCl, H2O2, 4-aminopyridine, and endothelin-1 were similar in control and hypoxic fetuses. In contrast, the DAs from the hypoxic fetuses showed increased contractile responses to norepinephrine and phenylephrine and impaired relaxations to acetylcholine, sodium nitroprusside, and isoproterenol. The relaxations induced by 8-Br-cGMP, forskolin, Y-27632, and hydroxyfasudil were not altered by chronic hypoxia. In conclusion, chronic in ovo hypoxia-induced growth retardation in fetal chickens and altered the response of the DA to adrenergic agonists and to endothelium-dependent and -independent relaxing agents. Our observations support the concept that prolonged patency of the DA in infants with IUGR may be partially related with hypoxia-induced changes in local vascular mechanisms.

  3. Punicalagin, a polyphenol in pomegranate juice, downregulates p53 and attenuates hypoxia-induced apoptosis in cultured human placental syncytiotrophoblasts.

    Science.gov (United States)

    Chen, Baosheng; Longtine, Mark S; Nelson, D Michael

    2013-11-15

    Oxidative stress is associated with placental dysfunction and suboptimal pregnancy outcomes. Therapeutic interventions to limit placental injury from oxidative stress are lacking. Punicalagin is an ellagitannin and a potent antioxidant in pomegranate juice. We showed that both pomegranate juice and punicalagin decrease oxidative stress and apoptosis in cultured syncytiotrophoblasts. p53 is involved in the oxidative stress-induced apoptosis in trophoblasts. We now test the hypothesis that punicalagin limits trophoblast injury in vitro by regulating the levels of p53. We examined the expression of p53, mouse double minute 2 homolog, p21, hypoxia-inducible factor (HIF) α, and selected members of the B cell lymphoma 2 (BCL2) family of proteins in cultured syncytiotrophoblasts exposed to ≤1% oxygen in the absence or presence of punicalagin. We found that punicalagin attenuated hypoxia-induced apoptosis in syncytiotrophoblasts, as quantified by levels of cleaved poly-ADP ribose polymerase. This protective effect was in part mediated by reduced p53 activity shown by decreased expression of p21, lower HIF1α expression, and limited activity of caspases 9 and 3. There was no change in expression of proteins in the BCL2 family, which are also important in apoptosis. The data support a role for downregulation of p53 in the protection of human trophoblasts by punicalagin.

  4. The role of endogenous nitric oxide and platelet-activating factor in hypoxia-induced intestinal injury in rats.

    Science.gov (United States)

    Caplan, M S; Hedlund, E; Hill, N; MacKendrick, W

    1994-02-01

    Nitric oxide is an endothelium-derived relaxing factor that promotes capillary integrity, inhibits leukocyte adherence and activation, and scavenges oxygen radicals. Because these effects are important in experimental intestinal injury, we studied the role of NO inhibition on hypoxia-induced bowel necrosis in the rat and investigated the interaction between platelet-activating factor (PAF) and NO in this model. Sprague-Dawley rats were treated with either hypoxia, NO synthase inhibition (NG-methyl-L-arginine [LNMA] or NG-nitro-L-arginine methyl ester [L-NAME]), hypoxia+LNMA, hypoxia+LNMA+NO donors, or hypoxia+LNMA+PAF receptor inhibition. Evaluations included blood pressure, superior mesenteric artery blood flow, arterial blood gases, histological intestinal injury, intestinal myeloperoxidase activity, and intestinal PAF activity. We found that hypoxia alone for 90 minutes (10% O2, partial O2 pressure = 45 mm Hg) or LNMA alone had no detrimental effects. However, hypoxia+LNMA together caused hypotension, metabolic acidosis, intestinal injury, increased intestinal myeloperoxidase activity, and elevated intestinal PAF concentrations that were prevented by exogenous L-arginine. Furthermore, the hypotension and intestinal injury was prevented by PAF receptor blockade. We conclude that endogenous NO protects the intestine from hypoxia-induced inflammation and injury, and the balance between local PAF and NO modulates the outcome of hypoxia-stressed intestine.

  5. MicroRNA-300 targets hypoxia inducible factor-3 alpha to inhibit tumorigenesis of human non-small cell lung cancer.

    Science.gov (United States)

    Zhang, Y; Guo, Y; Yang, C; Zhang, S; Zhu, X; Cao, L; Nie, W; Yu, H

    2017-01-01

    Non-small cell lung cancer (NSCLC) is one of the most deadly human cancers. MicroRNA-300 acts as both tumor promoter and suppressor in different types of cancer. Here, we try to identify the function of microRNA-300 in human NSCLC. We compared MicroRNA-300 levels between tumor tissues versus paired adjacent non-tumor lung tissues from NSCLC patients, and in NSCLC versus normal lung cell lines. Effects of microRNA-300 on cell proliferation, invasion and migration were examined in vitro, and on tumor growth in vivo using a xenograft mouse model. Potential mRNA targets of microRNA-300 were predicted and underlying mechanism was explored. MicroRNA-300 expression was lower in both NSCLC tissues and cell lines. Overexpression of microRNA-300 inhibited proliferation, invasion and migration of NSCLC cells in vitro, and tumor growth in vivo. MicroRNA-300 could directly bind to the 3'-UTR of hypoxia inducible factor-3 alpha (HIF3α) mRNA, and inhibit both its mRNA and protein expressions. Restoring HIF3α expression could rescue the inhibitory effects of microRNA-300 on tumorigenesis of NSCLC both in vitro and in vivo. MicroRNA-300 is a tumor suppressor microRNA in NSCLC by downregulating HIF3α expression. Both microRNA-300 and HIF3α may serve as potential therapeutic targets in NSCLC treatment.

  6. A Myeloid Hypoxia-inducible Factor 1α-Krüppel-like Factor 2 Pathway Regulates Gram-positive Endotoxin-mediated Sepsis*

    Science.gov (United States)

    Mahabeleshwar, Ganapati H.; Qureshi, Muhammad Awais; Takami, Yoichi; Sharma, Nikunj; Lingrel, Jerry B.; Jain, Mukesh K.

    2012-01-01

    Although Gram-positive infections account for the majority of cases of sepsis, the molecular mechanisms underlying their effects remains poorly understood. We investigated how cell wall components of Gram-positive bacteria contribute to the development of sepsis. Experimental observations derived from cultured primary macrophages and the cell line indicate that Gram-positive bacterial endotoxins induce hypoxia-inducible factor 1α (HIF-1α) mRNA and protein expression. Inoculation of live or heat-inactivated Gram-positive bacteria with macrophages induced HIF-1 transcriptional activity in macrophages. Concordant with these results, myeloid deficiency of HIF-1α attenuated Gram-positive bacterial endotoxin-induced cellular motility and proinflammatory gene expression in macrophages. Conversely, Gram-positive bacteria and their endotoxins reduced expression of the myeloid anti-inflammatory transcription factor Krüppel-like transcription factor 2 (KLF2). Sustained expression of KLF2 reduced and deficiency of KLF2 enhanced Gram-positive endotoxins induced HIF-1α mRNA and protein expression in macrophages. More importantly, KLF2 attenuated Gram-positive endotoxins induced cellular motility and proinflammatory gene expression in myeloid cells. Consistent with these results, mice deficient in myeloid HIF-1α were protected from Gram-positive endotoxin-induced sepsis mortality and clinical symptomatology. By contrast, myeloid KLF2-deficient mice were susceptible to Gram-positive sepsis induced mortality and clinical symptoms. Collectively, these observations identify HIF-1α and KLF2 as critical regulators of Gram-positive endotoxin-mediated sepsis. PMID:22110137

  7. Differentiation in neuroblastoma: diffusion-limited hypoxia induces neuro-endocrine secretory protein 55 and other markers of a chromaffin phenotype.

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    Fredrik Hedborg

    2010-09-01

    Full Text Available Neuroblastoma is a childhood malignancy of sympathetic embryonal origin. A high potential for differentiation is a hallmark of neuroblastoma cells. We have previously presented data to suggest that in situ differentiation in tumors frequently proceeds along the chromaffin lineage and that decreased oxygen (hypoxia plays a role in this. Here we explore the utility of Neuro-Endocrine Secretory Protein 55 (NESP55, a novel member of the chromogranin family, as a marker for this process.Immunohistochemical analyses and in situ hybridizations were performed on human fetal tissues, mouse xenografts of human neuroblastoma cell lines, and on specimens of human neuroblastoma/ganglioneuroma. Effects of anaerobic exposure on gene expression by cultured neuroblastoma cells was analyzed with quantitative real-time PCR. Fetal sympathetic nervous system expression of NESP55 was shown to be specific for chromaffin cell types. In experimental and clinical neuroblastoma NESP55 immunoreactivity was specific for regions of chronic hypoxia. NESP55 expression also correlated strikingly with morphological evidence of differentiation and with other chromaffin-specific patterns of gene expression, including IGF2 and HIF2α. Anaerobic culture of five neuroblastoma cell lines resulted in an 18.9-fold mean up-regulation of NESP55.The data confirms that chronic tumor hypoxia is a key microenvironmental factor for neuroblastoma cell differentiation, causing induction of chromaffin features and NESP55 provides a reliable marker for this neuronal to neuroendocrine transition. The hypoxia-induced phenotype is the predominant form of differentiation in stroma-poor tumors, while in stroma-rich tumors the chromaffin phenotype coexists with ganglion cell-like differentiation. The findings provide new insights into the biological diversity which is a striking feature of this group of tumors.

  8. Central venous hypoxemia is a determinant of human atrial ATP-sensitive potassium channel expression: evidence for a novel hypoxia-inducible factor 1alpha-Forkhead box class O signaling pathway.

    Science.gov (United States)

    Raeis, Véronique; Philip-Couderc, Pierre; Roatti, Angela; Habre, Walid; Sierra, Jorge; Kalangos, Afksendyios; Beghetti, Maurice; Baertschi, Alex J

    2010-05-01

    ATP-sensitive potassium channels couple cell excitability to energy metabolism, thereby providing life-saving protection of stressed cardiomyocytes. The signaling for ATP-sensitive potassium channel expression is still unknown. We tested involvement of biochemical and biophysical parameters and potential transcription factors Forkhead box (FOX) and hypoxia-inducible factor (HIF-1alpha). Right atrial tissues were obtained during surgery from 28 children with heart disease. Expression of K(+)-inward-rectifier subunits Kir6.1/Kir6.2; sulfonyl urea receptors (SURs) SUR1A/B and SUR2A/B; and FOX class O (FOXO) 1, FOXO3, FOXF2, and HIF-1alpha were related to 31 parameters, including personal data, blood chemistry, and echocardiography. Venous hypoxemia (but not other ischemia indicators, such as venous hypercapnia or low glucose) predicts increased Kir6.1 (Phypoxemia (P<0.003). Electrophoretic mobility-shift assays suggest causal links among hypoxia, HIF-1alpha, FOXO1, and Kir6.1. To mimic mild ischemia encountered in some patients, cultured rat atrial myocytes were tested in hypoxia, hypercapnia, or low glucose, with normal conditions serving as the control. Mild hypoxia (24-hour) increases expression of HIF-1alpha, FOXO1, and SUR2A/B/Kir6.1 in culture (P<0.01), whereas hypercapnia and low glucose have no or opposite effects. Gene knockdown of HIF-1alpha or FOXO1 by small-interfering RNAs abolishes hypoxia-induced expression of FOXO1 and SUR2A/B/Kir6.1. These results suggest that low tissue oxygen determines increased expression of the atrial SUR2A/B/Kir6.1 gene via activation of HIF-1alpha-FOXO1. Because increased SUR2A/B/Kir6.1 has known survival benefits, this pathway offers novel therapeutic targets for children with heart disease.

  9. Hypoxia Inducible Factor 1 (HIF1) Activation in U87 Glioma Cells Involves a Decrease in Reactive Oxygen Species Production and Protein Kinase C Activity

    Science.gov (United States)

    1998-06-29

    transcription factors NFkB, AP-l and Sox (Fandrey et al., 1994, Flohe et al., 1997, Hidalgo et al., 1997). Indeed, the bacterial transcription factor OxyR has...dehydrogenase A. Interaction between hypoxia-inducible factor 1 and cAMP response elements. J Biol Chern 270: 21021-7. Flohe , L., R. Brigelius- Flohe , C

  10. Lack of the Transcription Factor Hypoxia-Inducible Factor 1α (HIF-1α) in Macrophages Accelerates the Necrosis of Mycobacterium avium-Induced Granulomas.

    Science.gov (United States)

    Cardoso, Marcos S; Silva, Tânia M; Resende, Mariana; Appelberg, Rui; Borges, Margarida

    2015-09-01

    The establishment of mycobacterial infection is characterized by the formation of granulomas, which are well-organized aggregates of immune cells, namely, infected macrophages. The granuloma's main function is to constrain and prevent dissemination of the mycobacteria while focusing the immune response to a limited area. In some cases these lesions can grow progressively into large granulomas which can undergo central necrosis, thereby leading to their caseation. Macrophages are the most abundant cells present in the granuloma and are known to adapt under hypoxic conditions in order to avoid cell death. Our laboratory has developed a granuloma necrosis model that mimics the human pathology of Mycobacterium tuberculosis, using C57BL/6 mice infected intravenously with a low dose of a highly virulent strain of Mycobacterium avium. In this work, a mouse strain deleted of the hypoxia inducible factor 1α (HIF-1α) under the Cre-lox system regulated by the lysozyme M gene promoter was used to determine the relevance of HIF-1α in the caseation of granulomas. The genetic ablation of HIF-1α in the myeloid lineage causes the earlier emergence of granuloma necrosis and clearly induces an impairment of the resistance against M. avium infection coincident with the emergence of necrosis. The data provide evidence that granulomas become hypoxic before undergoing necrosis through the analysis of vascularization and quantification of HIF-1α in a necrotizing mouse model. Our results show that interfering with macrophage adaptation to hypoxia, such as through HIF-1α inactivation, accelerates granuloma necrosis. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  11. Molecular characterization and mRNA expression of hypoxia inducible factor-1 and cognate inhibiting factor in Macrobrachium nipponense in response to hypoxia.

    Science.gov (United States)

    Sun, Shengming; Xuan, Fujun; Fu, Hongtuo; Ge, Xianping; Zhu, Jian; Qiao, Hui; Jin, Shubo; Zhang, Wenyi

    2016-01-01

    Hypoxia inducible factors (HIFs) are considered to be the master switches of oxygen-dependent gene expression in mammalian species. Currently, very little is known about the function of this important pathway or the molecular structures of key players in the hypoxia-sensitive Oriental River Prawn Macrobrachium nipponense. In this study, HIFs-1α (HIF-1α), -1β (HIF-1β) and HIF 1-alpha inhibitor (FIH-1) from M. nipponense were cloned. The 4903-bp cDNA of M. nipponense HIF-1α (MnHIF-1α) encodes a protein of 1088 aa, M. nipponense HIF-1β (MnHIF-1β) spans 2042bp encoding 663 aa and the 1163bp M. nipponense FIH-1 (MnFIH-1) specifies a polypeptide of 345 aa. MnHIF-1 and MnFIH-1 homologs exhibit significant sequence similarity and share key functional domains with previously described vertebrate and invertebrate isoforms. Phylogenetic analysis identifies that genetic diversification of HIF-1 and FIH-1 occurred within the invertebrate lineage, indicating functional specialization of the oxygen sensing pathways in this group. Quantitative real-time RT-PCR demonstrated that MnHIF-1 and MnFIH-1 mRNA are expressed in different tissues and exhibit transcriptional responses to severe hypoxia in gill and muscle tissue, consistent with their putative role in oxygen sensing and the adaptive response to hypoxia. The role of HIF-1α in response to hypoxia was further investigated in the gills and muscles of prawns using in situ hybridization. These results suggested that HIF-1α plays an important role in oxygen sensing and homeostasis in M. nipponense. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Hypoxia-inducible factor-1α, vascular endothelial growth factor, inducible nitric oxide synthase, and endothelin-1 expression correlates with angiogenesis in congenital heart disease

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    Hsin-Ling Yin

    2016-07-01

    Full Text Available In Taiwan, the average prevalence of congenital heart disease (CHD is 13.08/1000 live births. Most children with CHD die before the age of 5 years; therefore, identifying treatment methods to extend the life of CHD patients is an important issue in clinical practice. The objective of this study is to evaluate the roles of hypoxia-inducible factor-1α (HIF-1α, vascular endothelial growth factor (VEGF, inducible nitric oxide synthase (iNOS, endothelin-1 (ET-1, and CD34 in CHD autopsy cases in comparison with autopsy cases without CHD. The study included 19 autopsy cases, which were divided into the following four groups: acyanotic CHD (n = 11, cyanotic CHD (n = 3, CHD associated with chromosomal abnormalities (n = 3, and complex CHD (n = 2. Heart specimens obtained from 10 autopsy cases without CHD were included as controls. Our results indicated that high percentages of HIF-1α (100%, VEGF (89.5%, iNOS (78.9%, and ET-1 (84.2% expressions were observed in CHD autopsy cases and this was found to be significant. HIF-1α induced by hypoxia could play a potential role in relating downstream gene expressions in CHD patients. Upregulation of VEGF by HIF-1α could play an important role in triggering angiogenesis to protect myocardial cell survival in a hypoxic microenvironment. Therefore, HIF-1α could be a significant prognosis marker in CHD and be a prospective candidate in the development of target therapy in cardiovascular diseases.

  13. Novel Pathway for Hypoxia-Induced Proliferation and Migration in Human Mesenchymal Stem Cells: Involvement of HIF-1α, FASN, and mTORC1.

    Science.gov (United States)

    Lee, Hyun Jik; Ryu, Jung Min; Jung, Young Hyun; Oh, Sang Yub; Lee, Sei-Jung; Han, Ho Jae

    2015-07-01

    The control of stem cells by oxygen signaling is an important way to improve various stem cell physiological functions and metabolic nutrient alteration. Lipid metabolism alteration via hypoxia is thought to be a key factor in controlling stem cell fate and function. However, the interaction between hypoxia and the metabolic and functional changes to stem cells is incompletely described. This study aimed to identify hypoxia-inducible lipid metabolic enzymes that can regulate umbilical cord blood (UCB)-derived human mesenchymal stem cell (hMSC) proliferation and migration and to demonstrate the signaling pathway that controls functional change in UCB-hMSCs. Our results indicate that hypoxia treatment stimulates UCB-hMSC proliferation, and expression of two lipogenic enzymes: fatty acid synthase (FASN) and stearoyl-CoA desaturase-1 (SCD1). FASN but not SCD1 is a key enzyme for regulation of UCB-hMSC proliferation and migration. Hypoxia-induced FASN expression was controlled by the hypoxia-inducible factor-1 alpha (HIF-1α)/SCAP/SREBP1 pathway. Mammalian target of rapamycin (mTOR) was phosphorylated by hypoxia, whereas inhibition of FASN by cerulenin suppressed hypoxia-induced mTOR phosphorylation as well as UCB-hMSC proliferation and migration. RAPTOR small interfering RNA transfection significantly inhibited hypoxia-induced proliferation and migration. Hypoxia-induced mTOR also regulated CDK2, CDK4, cyclin D1, cyclin E, and F-actin expression as well as that of c-myc, p-cofilin, profilin, and Rho GTPase. Taken together, the results suggest that mTORC1 mainly regulates UCB-hMSC proliferation and migration under hypoxia conditions via control of cell cycle and F-actin organization modulating factors. In conclusion, the HIF-1α/FASN/mTORC1 axis is a key pathway linking hypoxia-induced lipid metabolism with proliferation and migration in UCB-hMSCs. Stem Cells 2015;33:2182-2195. © 2015 AlphaMed Press.

  14. Constitutive expression of hypoxia-inducible factor-1 α in keratinocytes during the repair of skin wounds in horses.

    Science.gov (United States)

    Deschene, Karine; Céleste, Christophe; Boerboom, Derek; Theoret, Christine L

    2011-01-01

    As a transient hypoxic state exists within skin wounds in horses and may be important for the healing process, this study sought to identify a molecular hypoxia response occurring in horse limb and body wounds healing by second intention. Hypoxia-inducible factor 1α (HIF1α) protein expression was studied throughout repair by Western blotting and immunofluorescence. Paradoxically, HIF1α was strongly expressed in intact skin and its expression decreased dramatically following wounding (pwounded tissue. HIF1α levels reincreased in parallel with the epithelialization process, and more rapidly in body wounds than in limb wounds (pequine keratinocytes in both intact and wounded skin, and may regulate the expression of CDKN1A in this cell type. © 2011 by the Wound Healing Society.

  15. Fluorescence Lifetime Imaging Microscopy (FLIM) as a Tool to Investigate Hypoxia-Induced Protein-Protein Interaction in Living Cells.

    Science.gov (United States)

    Schützhold, Vera; Fandrey, Joachim; Prost-Fingerle, Katrin

    2018-01-01

    Fluorescence resonance energy transfer (FRET) is widely used as a method to investigate protein-protein interactions in living cells. A FRET pair donor fluorophore in close proximity to an appropriate acceptor fluorophore transfers emission energy to the acceptor, resulting in a shorter lifetime of the donor fluorescence. When the respective FRET donor and acceptor are fused with two proteins of interest, a reduction in donor lifetime, as detected by fluorescence lifetime imaging microscopy (FLIM), can be taken as proof of close proximity between the fluorophores and therefore interaction between the proteins of interest. Here, we describe the usage of time-domain FLIM-FRET in hypoxia-related research when we record the interaction of the hypoxia-inducible factor-1 (HIF-1) subunits HIF-1α and HIF-1β in living cells in a temperature- and CO 2 -controlled environment under the microscope.

  16. Efficacy of aqueous extract of Hippophae rhamnoides and its bio-active flavonoids against hypoxia-induced cell death.

    Science.gov (United States)

    Tulsawani, Rajkumar; Gupta, Rashmi; Misra, Kshipra

    2013-01-01

    To investigate the protective efficacy of aqueous extract of Hippophae rhamnoides against chronic hypoxic injury using primary rat hepatocytes. The extract was prepared using maceration method and characterized by its phenolic and flavonoid content and chemical antioxidant capacity using ferric reducing antioxidant power assay. Hepatocytes were maintained in hypoxia chamber (3% and 1% oxygen) for 72 h. The cells kept under normoxic condition served as control. The cells were treated with the extract and flavonoids; isorhamentin, kaempferol or qurecetin-3-galactoside. After the end of exposure period; cell survival, reactive oxygen species (ROS), leakage of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), reduced glutathione (GSH), glutathione peroxidase (GPx), and superoxide dismutase (SOD) levels were measured. The extract showed presence of high phenolic and flavonoid content with significant antioxidant activity in chemical assay. The cell exposed to hypoxia showed concentration dependent cell death and harbored higher reactive oxygen species. In addition, these cells showed significant leakage of intracellular LDH, ALT, and AST accompanied by the diminished levels/activities of GSH, GPx, and SOD. The treatment of cells with aqueous extract of H. rhamnoides reduced hypoxia-induced cell death and prevented increase in ROS levels and leakage of intracellular LDH, ALT, and AST from cells. Moreover, these cells maintained better levels/activities of GSH, GPx, and SOD in comparison to the respective controls. The major flavonoids present in aqueous extract of H. rhamnoides; quercetin-3-galactoside, kaempferol, and isorhamentin also prevented hypoxia induced cell injury individually or in combination, however, the protection offered by these compounds taken together could not match to that of the extract. Overall the findings reveal significance of aqueous extract of H. rhamnoides in controlling ROS-meditated hypoxic

  17. Hypoxia-induced miR-15a promotes mesenchymal ablation and adaptation to hypoxia during lung development in chicken.

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    Rui Hao

    Full Text Available The lungs undergo changes that are adaptive for high elevation in certain animal species. In chickens, animals bred at high elevations (e.g., Tibet chickens are better able to hatch and survive under high-altitude conditions. In addition, lowland chicken breeds undergo physiological effects and suffer greater mortality when they are exposed to hypoxic conditions during embryonic development. Although these physiological effects have been noted, the mechanisms that are responsible for hypoxia-induced changes in lung development and function are not known. Here we have examined the role of a particular microRNA (miRNA in the regulation of lung development under hypoxic conditions. When chicks were incubated in low oxygen (hypoxia, miR-15a was significantly increased in embryonic lung tissue. The expression level of miR-15a in hypoxic Tibet chicken embryos increased and remained relatively high at embryonic day (E16-20, whereas in normal chickens, expression increased and peaked at E19-20, at which time the cross-current gas exchange system (CCGS is developing. Bcl-2 was a translationally repressed target of miR-15a in these chickens. miR-16, a cluster and family member of miR-15a, was detected but did not participate in the posttranscriptional regulation of bcl-2. Around E19, the hypoxia-induced decrease in Bcl-2 protein resulted in apoptosis in the mesenchyme around the migrating tubes, which led to an expansion and migration of the tubes that would become the air capillary network and the CCGS. Thus, interfering with miR-15a expression in lung tissue may be a novel therapeutic strategy for hypoxia insults and altitude adaptation.

  18. Hypoxia-Induced miR-15a Promotes Mesenchymal Ablation and Adaptation to Hypoxia during Lung Development in Chicken

    Science.gov (United States)

    Hao, Rui; Hu, Xiaoxiang; Wu, Changxin; Li, Ning

    2014-01-01

    The lungs undergo changes that are adaptive for high elevation in certain animal species. In chickens, animals bred at high elevations (e.g., Tibet chickens) are better able to hatch and survive under high-altitude conditions. In addition, lowland chicken breeds undergo physiological effects and suffer greater mortality when they are exposed to hypoxic conditions during embryonic development. Although these physiological effects have been noted, the mechanisms that are responsible for hypoxia-induced changes in lung development and function are not known. Here we have examined the role of a particular microRNA (miRNA) in the regulation of lung development under hypoxic conditions. When chicks were incubated in low oxygen (hypoxia), miR-15a was significantly increased in embryonic lung tissue. The expression level of miR-15a in hypoxic Tibet chicken embryos increased and remained relatively high at embryonic day (E)16–20, whereas in normal chickens, expression increased and peaked at E19–20, at which time the cross-current gas exchange system (CCGS) is developing. Bcl-2 was a translationally repressed target of miR-15a in these chickens. miR-16, a cluster and family member of miR-15a, was detected but did not participate in the posttranscriptional regulation of bcl-2. Around E19, the hypoxia-induced decrease in Bcl-2 protein resulted in apoptosis in the mesenchyme around the migrating tubes, which led to an expansion and migration of the tubes that would become the air capillary network and the CCGS. Thus, interfering with miR-15a expression in lung tissue may be a novel therapeutic strategy for hypoxia insults and altitude adaptation. PMID:24887070

  19. Folic Acid Promotes Recycling of Tetrahydrobiopterin and Protects Against Hypoxia-Induced Pulmonary Hypertension by Recoupling Endothelial Nitric Oxide Synthase

    Science.gov (United States)

    Chalupsky, Karel; Kračun, Damir; Kanchev, Ivan; Bertram, Katharina

    2015-01-01

    Abstract Aims: Nitric oxide (NO) derived from endothelial NO synthase (eNOS) has been implicated in the adaptive response to hypoxia. An imbalance between 5,6,7,8-tetrahydrobiopterin (BH4) and 7,8-dihydrobiopterin (BH2) can result in eNOS uncoupling and the generation of superoxide instead of NO. Dihydrofolate reductase (DHFR) can recycle BH2 to BH4, leading to eNOS recoupling. However, the role of DHFR and eNOS recoupling in the response to hypoxia is not well understood. We hypothesized that increasing the capacity to recycle BH4 from BH2 would improve NO bioavailability as well as pulmonary vascular remodeling (PVR) and right ventricular hypertrophy (RVH) as indicators of pulmonary hypertension (PH) under hypoxic conditions. Results: In human pulmonary artery endothelial cells and murine pulmonary arteries exposed to hypoxia, eNOS was uncoupled as indicated by reduced superoxide production in the presence of the nitric oxide synthase inhibitor, L-(G)-nitro-L-arginine methyl ester (L-NAME). Concomitantly, NO levels, BH4 availability, and expression of DHFR were diminished under hypoxia. Application of folic acid (FA) restored DHFR levels, NO bioavailability, and BH4 levels under hypoxia. Importantly, FA prevented the development of hypoxia-induced PVR, right ventricular pressure increase, and RVH. Innovation: FA-induced upregulation of DHFR recouples eNOS under hypoxia by improving BH4 recycling, thus preventing hypoxia-induced PH. Conclusion: FA might serve as a novel therapeutic option combating PH. Antioxid. Redox Signal. 23, 1076–1091. PMID:26414244

  20. Absence of COX-2 exacerbates hypoxia-induced pulmonary hypertension and enhances contractility of vascular smooth muscle cells

    Science.gov (United States)

    Fredenburgh, Laura E.; Liang, Olin D.; Macias, Alvaro A.; Polte, Thomas R.; Liu, Xiaoli; Riascos, Dario F.; Chung, Su Wol; Schissel, Scott L.; Ingber, Donald E.; Mitsialis, S. Alex; Kourembanas, Stella; Perrella, Mark A.

    2008-01-01

    Background Cyclooxygenase-2 (COX-2) is upregulated in pulmonary artery smooth muscle cells (PASMC) during hypoxia and may play a protective role in the lung’s response to hypoxia. Selective COX-2 inhibition may have detrimental pulmonary vascular consequences during hypoxia. Methods and Results To investigate the role of COX-2 in the pulmonary vascular response to hypoxia, we subjected wild-type and COX-2 deficient mice to a model of chronic normobaric hypoxia. COX-2 null mice developed severe pulmonary hypertension with exaggerated elevation of right ventricular systolic pressure, significant right ventricular hypertrophy, and striking vascular remodeling following hypoxia. Pulmonary vascular remodeling in COX-2 deficient mice was characterized by PASMC hypertrophy, but not increased proliferation. Furthermore, COX-2 deficient mice had significant upregulation of the ET-1 receptor (ETAR) in the lung following hypoxia. Similarly, selective pharmacologic inhibition of COX-2 in wild-type mice exacerbated hypoxia-induced pulmonary hypertension and resulted in PASMC hypertrophy and increased ETAR expression in pulmonary arterioles. Absence of COX-2 in vascular smooth muscle cells during hypoxia in vitro augmented traction forces and enhanced contractility of an extracellular matrix. Treatment of COX-2 deficient PASMC with iloprost, a prostaglandin (PG) I2 analog, as well as PGE2, abrogated the potent contractile response to hypoxia and restored the wild-type phenotype. Conclusions Our findings reveal that hypoxia-induced pulmonary hypertension and vascular remodeling is exacerbated in the absence of COX-2 with enhanced ETA receptor expression and increased PASMC hypertrophy. COX-2 deficient PASMC have a maladaptive response to hypoxia manifested by exaggerated contractility which may be rescued by either COX-2-derived PGI2 or PGE2. PMID:18391113

  1. Methanolic extract of onion (Allium cepa) attenuates ischemia/hypoxia-induced apoptosis in cardiomyocytes via antioxidant effect.

    Science.gov (United States)

    Park, Sok; Kim, Mi-Young; Lee, Dong Ha; Lee, Soo Hwan; Baik, Eun Joo; Moon, Chang-Hyun; Park, Se Won; Ko, Eun Young; Oh, Sei-Ryang; Jung, Yi-Sook

    2009-06-01

    Although there is growing awareness of the beneficial potential of onion intake to lower the risk of cardiovascular disease, there is little information about the effect of onion on ischemic heart injury, one of the most common cardiovascular diseases. This study investigates the effect of the methanol-soluble extract of onion on ischemic injury in heart-derived H9c2 cells in vitro and in rat hearts in vivo. The underlying mechanism is also investigated. To evaluate the effect of onion on ischemia-induced cell death, LDH release and TUNEL-positivity were assessed in H9c2 cells, and the infarct size was measured in a myocardial infarct model. To investigate the mechanism of the cardioprotection by onion, the reactive oxygen species (ROS) level and the mitochondrial membrane potential (DeltaPsi(m)) were measured using an imaging technique; the caspase-3 activity was assayed, and Western blotting was performed to examine cytochrome c release in H9c2 cells. The methanolic extract of onion had a preventive effect on ischemia/hypoxia-induced apoptotic death in H9c2 cells in vitro and in rat heart in vivo. The onion extract (0.05 g/ml) inhibited the elevation of the ROS, mitochondrial membrane depolarization, cytochrome c release and caspase-3 activation during hypoxia in H9c2 cells. In the in vivo rat myocardial infarction model, onion extract (10 g/kg) significantly reduced the infarct size, the apoptotic cell death of the heart and the plasma MDA level. In conclusion, the results of this study suggest that the methanolic extract of onion attenuates ischemia/hypoxia-induced apoptosis in heart-derived H9c2 cells in vitro and in rat hearts in vivo, through, at least in part, an antioxidant effect.

  2. Proteomic analysis of signaling network regulation in renal cell carcinomas with differential hypoxia-inducible factor-2α expression.

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    Lokesh Dalasanur Nagaprashantha

    Full Text Available BACKGROUND: The loss of von Hippel-Lindau (VHL protein function leads to highly vascular renal tumors characterized by an aggressive course of disease and refractoriness to chemotherapy and radiotherapy. Loss of VHL in renal tumors also differs from tumors of other organs in that the oncogenic cascade is mediated by an increase in the levels of hypoxia-inducible factor-2α (HIF2α instead of hypoxia-inducible factor-1α (HIF1α. METHODS AND PRINCIPAL FINDINGS: We used renal carcinoma cell lines that recapitulate the differences between mutant VHL and wild-type VHL genotypes. Utilizing a method relying on extracted peptide intensities as a label-free approach for quantitation by liquid chromatography-mass spectrometry, our proteomics study revealed regulation of key proteins important for cancer cell survival, proliferation and stress-resistance, and implicated differential regulation of signaling networks in VHL-mutant renal cell carcinoma. We also observed upregulation of cellular energy pathway enzymes and the stress-responsive mitochondrial 60-kDa heat shock protein. Finding reliance on glutaminolysis in VHL-mutant renal cell carcinoma was of particular significance, given the generally predominant dependence of tumors on glycolysis. The data have been deposited to the ProteomeXchange with identifier PXD000335. CONCLUSIONS AND SIGNIFICANCE: Pathway analyses provided corroborative evidence for differential regulation of molecular and cellular functions influencing cancer energetics, metabolism and cell proliferation in renal cell carcinoma with distinct VHL genotype. Collectively, the differentially regulated proteome characterized by this study can potentially guide translational research specifically aimed at effective clinical interventions for advanced VHL-mutant, HIF2α-over-expressing tumors.

  3. Comparative GO: a web application for comparative gene ontology and gene ontology-based gene selection in bacteria.

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    Mario Fruzangohar

    Full Text Available The primary means of classifying new functions for genes and proteins relies on Gene Ontology (GO, which defines genes/proteins using a controlled vocabulary in terms of their Molecular Function, Biological Process and Cellular Component. The challenge is to present this information to researchers to compare and discover patterns in multiple datasets using visually comprehensible and user-friendly statistical reports. Importantly, while there are many GO resources available for eukaryotes, there are none suitable for simultaneous, graphical and statistical comparison between multiple datasets. In addition, none of them supports comprehensive resources for bacteria. By using Streptococcus pneumoniae as a model, we identified and collected GO resources including genes, proteins, taxonomy and GO relationships from NCBI, UniProt and GO organisations. Then, we designed database tables in PostgreSQL database server and developed a Java application to extract data from source files and loaded into database automatically. We developed a PHP web application based on Model-View-Control architecture, used a specific data structure as well as current and novel algorithms to estimate GO graphs parameters. We designed different navigation and visualization methods on the graphs and integrated these into graphical reports. This tool is particularly significant when comparing GO groups between multiple samples (including those of pathogenic bacteria from different sources simultaneously. Comparing GO protein distribution among up- or down-regulated genes from different samples can improve understanding of biological pathways, and mechanism(s of infection. It can also aid in the discovery of genes associated with specific function(s for investigation as a novel vaccine or therapeutic targets.http://turing.ersa.edu.au/BacteriaGO.

  4. Induction of erythropoiesis by hypoxia-inducible factor prolyl hydroxylase inhibitors without promotion of tumor initiation, progression, or metastasis in a VEGF-sensitive model of spontaneous breast cancer.

    Science.gov (United States)

    Seeley, Todd W; Sternlicht, Mark D; Klaus, Stephen J; Neff, Thomas B; Liu, David Y

    2017-01-01

    The effects of pharmacological hypoxia-inducible factor (HIF) stabilization were investigated in the MMTV-Neu(ndl)-YD5 (NeuYD) mouse model of breast cancer. This study first confirmed the sensitivity of this model to increased vascular endothelial growth factor (VEGF), using bigenic NeuYD;MMTV-VEGF-25 mice. Tumor initiation was dramatically accelerated in bigenic animals. Bigenic tumors were also more aggressive, with shortened doubling times and increased lung metastasis as compared to NeuYD controls. In separate studies, NeuYD mice were treated three times weekly from 7 weeks of age until study end with two different HIF prolyl hydroxylase inhibitors (HIF-PHIs), FG-4497 or roxadustat (FG-4592). In NeuYD mice, HIF-PHI treatments elevated erythropoiesis markers, but no differences were detected in tumor onset or the phenotypes of established tumors.

  5. The tyrosine phosphatase SHP-1 regulates hypoxia inducible factor-1α (HIF-1α protein levels in endothelial cells under hypoxia.

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    Stefan K Alig

    Full Text Available The tyrosine phosphatase SHP-1 negatively influences endothelial function, such as VEGF signaling and reactive oxygen species (ROS formation, and has been shown to influence angiogenesis during tissue ischemia. In ischemic tissues, hypoxia induced angiogenesis is crucial for restoring oxygen supply. However, the exact mechanism how SHP-1 affects endothelial function during ischemia or hypoxia remains unclear. We performed in vitro endothelial cell culture experiments to characterize the role of SHP-1 during hypoxia.SHP-1 knock-down by specific antisense oligodesoxynucleotides (AS-Odn increased cell growth as well as VEGF synthesis and secretion during 24 hours of hypoxia compared to control AS-Odn. This was prevented by HIF-1α inhibition (echinomycin and apigenin. SHP-1 knock-down as well as overexpression of a catalytically inactive SHP-1 (SHP-1 CS further enhanced HIF-1α protein levels, whereas overexpression of a constitutively active SHP-1 (SHP-1 E74A resulted in decreased HIF-1α levels during hypoxia, compared to wildtype SHP-1. Proteasome inhibition (MG132 returned HIF-1α levels to control or wildtype levels respectively in these cells. SHP-1 silencing did not alter HIF-1α mRNA levels. Finally, under hypoxic conditions SHP-1 knock-down enhanced intracellular endothelial reactive oxygen species (ROS formation, as measured by oxidation of H2-DCF and DHE fluorescence.SHP-1 decreases half-life of HIF-1α under hypoxic conditions resulting in decreased cell growth due to diminished VEGF synthesis and secretion. The regulatory effect of SHP-1 on HIF-1α stability may be mediated by inhibition of endothelial ROS formation stabilizing HIF-1α protein. These findings highlight the importance of SHP-1 in hypoxic signaling and its potential as therapeutic target in ischemic diseases.

  6. Hypoxia-Inducible Factor-1α Expression in Kidney Transplant Biopsy Specimens After Reperfusion Is Associated With Early Recovery of Graft Function After Cadaveric Kidney Transplantation.

    Science.gov (United States)

    Oda, T; Ishimura, T; Yokoyama, N; Ogawa, S; Miyake, H; Fujisaw, M

    Ischemia/reperfusion injury during kidney transplantation (KTx) delays allograft recovery. Hypoxia-inducible factor-1α (HIF-1α) is the key regulator of the protective response to ischemia/reperfusion injury. We evaluated the impact of the HIF-1α signaling pathway on allograft recovery during cadaveric KTx. Between 1996 and 2015, 46 patients underwent cadaveric KTx. The expression levels of HIF-1α-related proteins, including phosphoinositide 3-kinase, phosphorylated (p)-Akt, p-mammalian target of rapamycin, p-Eukaryotic translation initiation factor 4E, p-S6 ribosomal protein, and HIF-1α, were immunohistochemically evaluated and semi-quantitatively scored in graft biopsy specimens after 1 hour of revascularization. Ten kidney biopsy specimens collected during donor nephrectomy for living KTx were used as controls. Delayed graft function (DGF) was defined as the need for dialysis within 1 week of KTx. We compared the staining scores of each protein and several clinical parameters between patients with and those without DGF. Expression levels of all six proteins in specimens after revasculization were elevated compared with those in controls. Thirty-five patients had DGF. Expression levels of PI3K, p-AKT, p-mTOR, p-eIF4E, and HIF-1α were significantly higher in patients without DGF than in those with DGF. Univariate analysis identified expression levels of p-Akt, p-S6, and HIF-1α, in addition to donor type (heart beating/non-heart beating), cold ischemic time, and donor age as significant predictors of DGF. Of these, only expression levels of HIF-1α and donor type were independently associated with DGF in multivariate analysis. Up-regulation of HIF-1α in allografts after reperfusion may be a predictor of early recovery after cadaveric KTx. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Expression of Hypoxia-Inducible Factor (HIF-1a-Vascular Endothelial Growth Factor (VEGF-Inhibitory Growth Factor (ING-4- axis in sarcoidosis patients

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    Tzouvelekis Argyris

    2012-11-01

    Full Text Available Abstract Background Sarcoidosis is a granulomatous disorder of unknown etiology. The term of immunoangiostasis has been addressed by various studies as potentially involved in the disease pathogenesis. The aim of the study was to investigate the expression of the master regulator of angiogenesis hypoxia inducible factor (HIF-1a – vascular endothelial growth factor (VEGF- inhibitor of growth factor 4-(ING4 - axis within sarcoid granuloma. Methods A total of 37 patients with sarcoidosis stages II-III were recruited in our study. Tissue microarray technology coupled with immunohistochemistry analysis were applied to video-assisted thoracoscopic surgery (VATS lung biopsy samples collected from 37 sarcoidosis patients and 24 controls underwent surgery for benign lesions of the lung. Computerized image analysis was used to quantify immunohistochemistry results. qRT-PCR was used to assess HIF-1a and ING4 expression in 10 sarcoidosis mediastinal lymph node and 10 control lung samples. Results HIF-1a and VEGF-ING4 expression, both in protein and mRNA level, was found to be downregulated and upregulated, respectively, in sarcoidosis samples compared to controls. Immunohistochemistry coupled with computerized image analysis revealed minimal expression of HIF-1a within sarcoid granulomas whereas an abundant staining of ING4 and VEGF in epithelioid cells was also visualized. Conclusions Our data suggest an impairment of the HIF-1a – VEGF axis, potentialy arising by ING4 overexpression and ultimately resulting in angiostasis and monocyte recruitment within granulomas. The concept of immunoangiostasis as a possible protection mechanism against antigens of infectious origin needs further research to be verified.

  8. Activation of Dll4/Notch Signaling and Hypoxia-Inducible Factor-1 Alpha Facilitates Lymphangiogenesis in Lacrimal Glands in Dry Eye.

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    Ji Hwan Min

    Full Text Available By using hypoxia-inducible factor-1 alpha conditional knockout (HIF-1α CKO mice and a dry eye (DE mouse model, we aimed to determine the role played by delta-like ligand 4 (Dll4/Notch signaling and HIF-1α in the lymphangiogenesis of lacrimal glands (LGs.C57BL/6 mice were housed in a controlled-environment chamber for DE induction. During DE induction, the expression level of Dll4/Notch signaling and lymphangiogenesis in LGs was measured by quantitative RT-PCR, immunoblot, and immunofluorescence staining. Next, lymphangiogenesis was measured after Dll4/Notch signal inhibition by anti-Dll4 antibody or γ-secretase inhibitor. Using HIF-1α CKO mice, the expression of Dll4/Notch signaling and lymphangiogenesis in LGs of DE-induced HIF-1α CKO mice were assessed. Additionally, the infiltration of CD45+ cells in LGs was assessed by immunohistochemical (IHC staining and flow cytometry for each condition.DE significantly upregulated Dll4/Notch and lymphangiogenesis in LGs. Inhibition of Dll4/Notch significantly suppressed lymphangiogenesis in LGs. Compared to wild-type (WT mice, DE induced HIF-1α CKO mice showed markedly low levels of Dll4/Notch and lymphangiogenesis. Inhibition of lymphangiogenesis by Dll4/Notch suppression resulted in increased CD45+ cell infiltration in LGs. Likewise, CD45+ cells infiltrated more in the LGs of HIF-1α CKO DE mice than in non-DE HIF-1α CKO mice.Dll4/Notch signaling and HIF-1α are closely related to lymphangiogenesis in DE-induced LGs. Lymphangiogenesis stimulated by Dll4/Notch and HIF-1α may play a role in protecting LGs from DE-induced inflammation by aiding the clearance of immune cells from LGs.

  9. Effects of stem cell factor on hypoxia-inducible factor 1 alpha accumulation in human acute myeloid leukaemia and LAD2 mast cells.

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    Bernhard F Gibbs

    Full Text Available Stem cell factor (SCF is a hematopoietic growth factor that exerts its activity by signalling through the tyrosine kinase receptor known as Kit or CD117. SCF-Kit signalling is crucial for the survival, proliferation and differentiation of hematopoietic cells of myeloid lineage. Furthermore, since myeloid leukaemia cells express the Kit receptor, SCF may play an important role in myeloid leukaemia progression too. However, the mechanisms of this pathophysiological effect remain unclear. Recent evidence shows that SCF triggers accumulation of the inducible alpha subunit of hypoxia-inducible factor 1 (HIF-1 in hematopoietic cells--a transcription complex that plays a pivotal role in cellular adaptation to low oxygen availability. However, it is unknown how SCF impacts on HIF-1α accumulation in human myeloid leukaemia and mast cells. Here we show that SCF induces HIF-1α accumulation in THP-1 human myeloid leukaemia cells but not in LAD2 mast cells. We demonstrated that LAD2 cells have a more robust glutathione (GSH-dependent antioxidative system compared to THP-1 cells and are therefore protected against the actions of ROS generated in an SCF-dependent manner. BSO-induced GSH depletion led to a significant decrease in HIF-1α prolyl hydroxylase (PHD activity in THP-1 cells and to near attenuation of it in LAD2 cells. In THP-1 cells, SCF-induced HIF-1α accumulation is controlled via ERK, PI3 kinase/PKC-δ/mTOR-dependent and to a certain extent by redox-dependent mechanisms. These results demonstrate for the first time an important cross-talk of signalling pathways associated with HIF-1 activation--an important stage of the myeloid leukaemia cell life cycle.

  10. Comparison of Hypoxia-inducible Factor-1 alpha Expression Before and After Transcatheter Arterial Embolization in Rabbit VX2 Liver Tumors

    Science.gov (United States)

    Virmani, Sumeet; Rhee, Thomas K.; Ryu, Robert K.; Sato, Kent T.; Lewandowski, Robert J.; Mulcahy, Mary F.; Kulik, Laura M.; Szolc-Kowalska, Barbara; Woloschak, Gayle E.; Yang, Guang-Yu; Salem, Riad; Larson, Andrew C.; Omary, Reed A.

    2008-01-01

    Purpose Hypoxia-inducible factor-1 alpha (HIF-1 α) expression has been linked with increased mortality and treatment failure in various cancers. The purpose of this study was to test the hypothesis that transcatheter arterial embolization (TAE) induces expression of HIF-1 α within the same rabbit VX2 liver tumor. Materials and Methods Seven VX2 tumors were grown in the livers of 5 New Zealand white rabbits. Ultrasound guided biopsies were taken before and 10 min after TAE from all tumors. Pre- and post- TAE tumor biopsy specimens along with post- TAE whole liver tumor sections were stained with HIF-1 α antibody and analyzed for percentage of HIF-1 α positive nuclei using a spectral unmixing system mounted on a high powered microscope. Statistical data comparisons were performed using Wilcoxon signed-rank test (alpha=0.05). Results TAE of liver tumors resulted in a statistically significant increase in the mean percentage of HIF-1 α expression. The mean percentage of HIF-1 α positive stained nuclei increased from 23 % ± 3.5% in pre- TAE biopsy specimens to 41% ± 8.7% (p< 0.02) in post- TAE biopsy specimens. The increase was even more significant when mean percentage of HIF-1 α positive stained nuclei from the same pre- TAE biopsy specimens were compared to sections from post- TAE whole tumor specimens [60% ± 8.9% (p<0.02)]. Conclusions The study revealed that hypoxia caused by TAE of VX2 liver tumors activates HIF-1 α, a transcription factor that in turn regulates other pro-angiogenic factors. PMID:18922400

  11. Cloning and characterization of hypoxia-inducible factor-1 subunits from Ascaris suum - a parasitic nematode highly adapted to changes of oxygen conditions during its life cycle.

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    Goto, Miho; Amino, Hisako; Nakajima, Mikage; Tsuji, Naotoshi; Sakamoto, Kimitoshi; Kita, Kiyoshi

    2013-03-01

    The parasitic nematode Ascaris suum successfully adapts to a significant decrease in oxygen availability during its life cycle by altering its metabolic system dramatically. However, little is known about the regulatory mechanisms of adaptation to hypoxic environments in A. suum. In multicellular organisms, hypoxia-inducible factor-1 (HIF-1), a heterodimeric transcription factor composed of HIF-1α and HIF-1β subunits, is a master regulator of genes involved in adaptation to hypoxia. In the present study, cDNAs encoding HIF-1α and HIF-1β were cloned from A. suum and characterized. The full-length A. suum hif-1α and hif-1β cDNAs contain open reading frames encoding proteins with 832 and 436 amino acids, respectively. In the deduced amino acid sequences of A. suum HIF-1α and HIF-1β, functional domains essential for DNA-binding, dimerization, and oxygen-dependent prolyl hydroxylation were conserved. The interaction between A. suum HIF-1α and HIF-1β was confirmed by the yeast two-hybrid assay. Both A. suum hif-1α and hif-1β mRNAs were expressed at all stages examined (fertilized eggs, third-stage larvae, lung-stage larvae, young adult worms, and adult muscle tissue), and most abundantly in the aerobic free-living third-stage larvae, followed by a gradual decrease after infection of the host. hif-1 mRNA transcription was not sensitive to the oxygen environment in either third-stage larvae or adult worms (muscle tissue), and was regulated in a stage-specific manner. High expression of hif-1 mRNAs in third-stage larvae suggests its contribution to pre-adaptation to a hypoxic environment after infection of their host. Sequence analysis of 5'-upstream regions of mitochondrial complex II (succinate-ubiquinone reductase/quinol-fumarate reductase) genes, which show stage-specific expression and play an important role in oxygen adaptation during the life cycle, revealed that all subunits except for the adult-type flavoprotein subunit (Fp) possess putative hypoxia

  12. Hypoxia inducible factor-1 (HIF-1)–flavin containing monooxygenase-2 (FMO-2) signaling acts in silver nanoparticles and silver ion toxicity in the nematode, Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Hyun-Jeong; Ahn, Jeong-Min [School of Environmental Engineering and Graduate School of Energy and Environmental System Engineering, University of Seoul, 90 Jeonnong-dong, Dongdaemun-gu, Seoul 130-743 (Korea, Republic of); Kim, Younghun [Department of Chemical Engineering, Kwangwoon University, 447-1, Wolgye-dong, Nowon-gu, Seoul 139-701 (Korea, Republic of); Choi, Jinhee, E-mail: jinhchoi@uos.ac.kr [School of Environmental Engineering and Graduate School of Energy and Environmental System Engineering, University of Seoul, 90 Jeonnong-dong, Dongdaemun-gu, Seoul 130-743 (Korea, Republic of)

    2013-07-15

    In the present study, nanotoxicity mechanism associated with silver nanoparticles (AgNPs) exposure was investigated on the nematode, Caenorhabditis elegans focusing on the hypoxia response pathway. In order to test whether AgNPs-induced hypoxia inducible factor-1 (HIF-1) activation was due to hypoxia or to oxidative stress, depletion of dissolved oxygen (DO) in the test media and a rescue effect using an antioxidant were investigated, respectively. The results suggested that oxidative stress was involved in activation of the HIF-1 pathway. We then investigated the toxicological implications of HIF-1 activation by examining the HIF-1 mediated transcriptional response. Of the genes tested, increased expression of the flavin containing monooxygenase-2 (FMO-2) gene was found to be the most significant as induced by AgNPs exposure. We found that AgNPs exposure induced FMO-2 activation in a HIF-1 and p38 MAPK PMK-1 dependent manner, and oxidative stress was involved in it. We conducted all experiments to include comparison of AgNPs and AgNO{sub 3} in order to evaluate whether any observed toxicity was due to dissolution or particle specific. The AgNPs and AgNO{sub 3} did not produce any qualitative differences in terms of exerting toxicity in the pathways observed in this study, however, considering equal amount of silver mass, in every endpoint tested the AgNPs were found to be more toxic than AgNO{sub 3}. These results suggest that Ag nanotoxicity is dependent not only on dissolution of Ag ion but also on particle specific effects and HIF-1–FMO-2 pathway seems to be involved in it. - Highlights: • HIF-1 signaling was investigated in C. elegans exposed to AgNPs and AgNO{sub 3}. • HIF-1 and PMK-1 were needed for AgNPs- and AgNO{sub 3}-induced fmo-2 gene expression. • PMK-1–HIF-1–FMO-2 pathway was dependent on oxidative stress. • AgNPs and AgNO{sub 3} did not produce any qualitative differences in HIF-1 signaling. • AgNPs were more toxic than an equal

  13. Neuroprotective action of raloxifene against hypoxia-induced damage in mouse hippocampal cells depends on ERα but not ERβ or GPR30 signalling.

    Science.gov (United States)

    Rzemieniec, J; Litwa, E; Wnuk, A; Lason, W; Gołas, A; Krzeptowski, W; Kajta, M

    2015-02-01

    Raloxifene is the selective estrogen receptor modulator (SERM) currently used in clinical practice to activate estrogen receptors (ERs) in bone tissue and to antagonise ERs in breast and uterine cancers. Little is known, however, about mechanisms of action of raloxifene on hypoxia-induced neuronal cell damage. The aim of the present study was to investigate the neuroprotective potential of raloxifene against hypoxia-induced damage of mouse hippocampal cells in primary cultures, with a particular focus on raloxifene interactions with the classical nuclear ERs (ERα, ERβ) and the recently identified membrane ER G-protein-coupled receptor 30 (GPR30). In this study, 18 h of hypoxia increased hypoxia inducible factor 1 alpha (Hif1α) mRNA expression and induced apoptotic processes, such as loss of the mitochondrial membrane potential, activation of caspase-3 and fragmentation of cell nuclei based on Hoechst 33342 staining. These effects were accompanied by reduced ATPase and intracellular esterase activities as well as substantial lactate dehydrogenase (LDH) release from cells exposed to hypoxia. Our study demonstrated strong neuroprotective and anti-apoptotic caspase-3-independent actions of raloxifene in hippocampal cells exposed to hypoxia. Raloxifene also inhibited the hypoxia-induced decrease in Erα mRNA expression and attenuated the hypoxia-induced rise in Erβ and Gpr30 mRNA expression levels. Impact of raloxifene on hypoxia-affected Erα mRNA was mirrored by fluctuations in the protein level of the receptor as demonstrated by Western blot and immunofluorescent labelling. Raloxifene-induced changes in Erβ mRNA expression level were in parallel with ERβ immunofluorescent labeling. However, changes in Gpr30 mRNA level were not reflected by changes in the protein levels measured either by ELISA, Western blot or immunofluorescent staining at 24h post-treatment. Using specific siRNAs, we provided evidence for a key involvement of ERα, but not ERβ or GPR30 in

  14. Investigating the Regulation and Potential Role of Nonhypoxic Hypoxia-Inducible Factor 1 (HIF-1) in Aromatase Inhibitor Resistant Breast Cancer

    Science.gov (United States)

    2013-10-01

    obese and overweight patients with ER+ breast cancer to neoadjuvant aromatase inhibitor therapy. My role in this clinical trial is to analyze HIF-1 and...with drug resistance in different cancer cell types, including chronic myeloid leukemia cells (Zhao et al. Oncogene. 2010), gastric cancer cells (Liu...Hypoxia- Inducible Factor 1 (HIF-1) in Aromatase Inhibitor Resistant Breast Cancer PRINCIPAL INVESTIGATOR: Armina Kazi CONTRACTING

  15. Hypoxia-induced downregulation of autophagy mediator Beclin 1 reduces the susceptibility of malignant intestinal epithelial cells to hypoxia-dependent apoptosis.

    Science.gov (United States)

    Yoo, Byong Hoon; Wu, Xue; Derouet, Mathieu; Haniff, Mehnaaz; Eskelinen, Eeva-Liisa; Rosen, Kirill

    2009-11-01

    Disruption of tumor blood supply causes tumor hypoxia. Hypoxia can induce cell death, but cancer cells that remain viable in the absence of oxygen often possess an increased survival potential, and tumors formed by these cells tend to grow particularly aggressively. Thus, developing approaches aimed at increasing the susceptibility of malignant cells to hypoxia-induced death represents a potentially important avenue for cancer treatment. Molecular mechanisms that control the survival of cancer cells under hypoxia are not well understood. In an effort to understand them we found that hypoxia downregulates Beclin 1, a mediator of autophagy, in malignant intestinal epithelial cells. The reversal of this downregulation promoted autophagosome accumulation, enhanced the activation of a pro-apoptotic protease caspase-9 and subsequent caspase-9-dependent activation of two other pro-apoptotic proteases caspases 3 and 7 in these cells. Furthermore, the reversal of hypoxia-induced downregulation of Beclin 1-stimulated caspase-9-dependent apoptosis of the indicated cells under hypoxia. Interestingly, we found that Beclin 1-dependent caspase-9 activation in hypoxic cells was not associated with an increased release of cytochrome c from the mitochondria to the cytoplasm (such release represents a frequently occurring mechanism for caspase-9 activation). We also observed that Beclin 1-dependent apoptosis of hypoxic malignant cells was independent of FADD, a mediator of death receptor signaling. We conclude that hypoxia triggers a feedback mechanism that delays apoptosis of oxygen-deprived malignant intestinal epithelial cells and is driven by hypoxia-induced Beclin 1 downregulation. Thus, approaches aimed at the disruption of this mechanism can be expected to enhance the susceptibility of such cells to hypoxia-induced apoptosis.

  16. Effect of Moderate Hepatic Impairment on the Pharmacokinetics and Pharmacodynamics of Roxadustat, an Oral Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitor

    OpenAIRE

    Groenendaal-van de Meent, Dorien; Adel, Martin den; Noukens, Jan; Rijnders, Sanne; Krebs-Brown, Axel; Mateva, Lyudmila; Alexiev, Assen; Schaddelee, Marloes

    2016-01-01

    Background and Objective Roxadustat is a hypoxia-inducible factor prolyl hydroxylase inhibitor in phase III development for the treatment of anaemia associated with chronic kidney disease. This study evaluated the effects of moderate hepatic impairment on roxadustat pharmacokinetics, pharmacodynamics and tolerability. Methods This was an open-label study in which eight subjects with moderate hepatic impairment (liver cirrhosis Child?Pugh score 7?9) and eight subjects with normal hepatic funct...

  17. Comparative gene expression analysis of murine retina and brain.

    Science.gov (United States)

    Hackam, Abigail S; Qian, Jiang; Liu, Dongmei; Gunatilaka, Tushara; Farkas, Ronald H; Chowers, Itay; Kageyama, Masaaki; Parmigiani, Giovanni; Zack, Donald J

    2004-08-31

    Several high-throughput studies have described gene expression in the central nervous system (CNS), and recently there has been increasing interest in analyzing how gene expression compares in different regions of the CNS. As the retina is often used as a model system to study CNS development and function, we compared retina and brain gene expression using microarray analyses. Mouse retina, brain and liver RNA was hybridized to a custom cDNA microarray containing 5,376 genes and ESTs, and the data from the quantified scanned images were analyzed using Bioconductor and SAM. Preferential retina expression was confirmed by real-time PCR. The cellular distribution of genes newly identified as retina enriched genes was determined by immunohistochemistry. Using stringent statistical analyses we identified 733 genes that were preferentially expressed in retina and 389 in brain. The retina-liver hybridizations identified an additional 837 retina enriched genes. The cellular distribution in the retina was determined for two genes that had not previously been reported to be expressed in the retina, the transcription regulatory proteins EWS and PCPB1. Both proteins were found primarily in the inner nuclear layer. Finally, a comparison of the microarray data to publicly available SAGE and EST library databases demonstrated only limited overlap of the sets of retina enriched genes identified by the different methodologies. The preferential retinal expression of a subset of genes from the microarray, which were not identified as differentially expressed by other methods, was confirmed by quantitative PCR. The finding of differences in the groups of identified retina enriched genes from the various profiling techniques supports the use of multiple approaches to obtain a more complete description of retinal gene expression. Characterization of gene expression profiles of retina and brain may facilitate the understanding of the processes that underlie differences between the retina

  18. Distinctive expression patterns of hypoxia-inducible factor-1α and endothelial nitric oxide synthase following hypergravity exposure.

    Science.gov (United States)

    Yoon, Gun; Oh, Choong Sik; Kim, Hyun-Soo

    2016-06-07

    This study was designed to examine the expression of hypoxia-inducible factor-1α (HIF-1α) and the level and activity of endothelial nitric oxide synthase (eNOS) in the hearts and livers of mice exposed to hypergravity. Hypergravity-induced hypoxia and the subsequent post-exposure reoxygenation significantly increased cardiac HIF-1α levels. Furthermore, the levels and activity of cardiac eNOS also showed significant increase immediately following hypergravity exposure and during the reoxygenation period. In contrast, the expression of phosphorylated Akt (p-Akt) and phosphorylated extracellular signal-regulated kinase (p-ERK) showed significant elevation only during the reoxygenation period. These data raise the possibility that the increase in cardiac HIF-1α expression induced by reoxygenation involves a cascade of signaling events, including activation of the Akt and ERK pathways. In the liver, HIF-1α expression was significantly increased immediately after hypergravity exposure, indicating that hypergravity exposure to causes hepatocellular hypoxia. The hypergravity-exposed livers showed significantly higher eNOS immunoreactivity than did those of control mice. Consistent with these results, significant increases in eNOS activity and nitrate/nitrite levels were also observed. These findings suggest that hypergravity-induced hypoxia plays a significant role in the upregulation of hepatic eNOS.

  19. Hypoxia-inducible factor-1α activation improves renal oxygenation and mitochondrial function in early chronic kidney disease.

    Science.gov (United States)

    Thomas, Joanna L; Pham, Hai; Li, Ying; Hall, Elanore; Perkins, Guy A; Ali, Sameh S; Patel, Hemal H; Singh, Prabhleen

    2017-08-01

    The pathophysiology of chronic kidney disease (CKD) is driven by alterations in surviving nephrons to sustain renal function with ongoing nephron loss. Oxygen supply-demand mismatch, due to hemodynamic adaptations, with resultant hypoxia, plays an important role in the pathophysiology in early CKD. We sought to investigate the underlying mechanisms of this mismatch. We utilized the subtotal nephrectomy (STN) model of CKD to investigate the alterations in renal oxygenation linked to sodium (Na) transport and mitochondrial function in the surviving nephrons. Oxygen delivery was significantly reduced in STN kidneys because of lower renal blood flow. Fractional oxygen extraction was significantly higher in STN. Tubular Na reabsorption was significantly lower per mole of oxygen consumed in STN. We hypothesized that decreased mitochondrial bioenergetic capacity may account for this and uncovered significant mitochondrial dysfunction in the early STN kidney: higher oxidative metabolism without an attendant increase in ATP levels, elevated superoxide levels, and alterations in mitochondrial morphology. We further investigated the effect of activation of hypoxia-inducible factor-1α (HIF-1α), a master regulator of cellular hypoxia response. We observed significant improvement in renal blood flow, glomerular filtration rate, and tubular Na reabsorption per mole of oxygen consumed with HIF-1α activation. Importantly, HIF-1α activation significantly lowered mitochondrial oxygen consumption and superoxide production and increased mitochondrial volume density. In conclusion, we report significant impairment of renal oxygenation and mitochondrial function at the early stages of CKD and demonstrate the beneficial role of HIF-1α activation on renal function and metabolism.

  20. Role of Hypoxia Inducible Factor-1α (HIF-1α) in Innate Defense against Uropathogenic Escherichia coli Infection

    Science.gov (United States)

    Lin, Ann E.; Beasley, Federico C.; Olson, Joshua; Keller, Nadia; Shalwitz, Robert A.; Hannan, Thomas J.; Hultgren, Scott J.; Nizet, Victor

    2015-01-01

    Uropathogenic E. coli (UPEC) is the primary cause of urinary tract infections (UTI) affecting approximately 150 million people worldwide. Here, we revealed the importance of transcriptional regulator hypoxia-inducible factor-1 α subunit (HIF-1α) in innate defense against UPEC-mediated UTI. The effects of AKB-4924, a HIF-1α stabilizing agent, were studied using human uroepithelial cells (5637) and a murine UTI model. UPEC adherence and invasion were significantly reduced in 5637 cells when HIF-1α protein was allowed to accumulate. Uroepithelial cells treated with AKB-4924 also experienced reduced cell death and exfoliation upon UPEC challenge. In vivo, fewer UPEC were recovered from the urine, bladders and kidneys of mice treated transurethrally with AKB-4924, whereas increased bacteria were recovered from bladders of mice with a HIF-1α deletion. Bladders and kidneys of AKB-4924 treated mice developed less inflammation as evidenced by decreased pro-inflammatory cytokine release and neutrophil activity. AKB-4924 impairs infection in uroepithelial cells and bladders, and could be correlated with enhanced production of nitric oxide and antimicrobial peptides cathelicidin and β-defensin-2. We conclude that HIF-1α transcriptional regulation plays a key role in defense of the urinary tract against UPEC infection, and that pharmacological HIF-1α boosting could be explored further as an adjunctive therapy strategy for serious or recurrent UTI. PMID:25927232

  1. Transcriptional repression of Na-K-2Cl cotransporter NKCC1 by hypoxia-inducible factor-1.

    Science.gov (United States)

    Ibla, Juan C; Khoury, Joseph; Kong, Tianqing; Robinson, Andreas; Colgan, Sean P

    2006-08-01

    Tissue edema is commonly associated with hypoxia. Generally, such episodes of fluid accumulation are self-limiting. At present, little is known about mechanisms to compensate excessive fluid transport. Here we describe an adaptive mechanism to dampen fluid loss during hypoxia. Initial studies confirmed previous observations of attenuated electrogenic Cl- secretion after epithelial hypoxia. A screen of known ion transporters in Cl- -secreting epithelia revealed selective downregulation of Na-K-2Cl cotransporter NKCC1 mRNA, protein, and function. Subsequent studies identified transcriptional repression of NKCC1 mediated by hypoxia-inducible factor (HIF). Chromatin immunoprecipitation analysis identified a functional HIF binding site oriented on the antisense strand of genomic DNA downstream of the transcription start site corresponding to the NKCC1 5'-untranslated region. Additional in vivo studies using conditional Hif1a-null mice revealed that the loss of HIF-1alpha in Cl- -secreting epithelia results in a loss of NKCC1 repression. These studies describe a novel regulatory pathway for NKCC1 transcriptional repression by hypoxia. These results suggest that HIF-dependent repression of epithelial NKCC1 may provide a compensatory mechanism to prevent excessive fluid loss during hypoxia.

  2. Hypoxia-inducible factor 1α predicts recurrence in high-grade soft tissue sarcoma of extremities and trunk wall

    DEFF Research Database (Denmark)

    Nyström, Harriet; Jönsson, M; Werner-Hartman, L

    2017-01-01

    BACKGROUND AND AIM: Sarcomas are of mesenchymal origin and typically show abundant tumour stroma and presence of necrosis. In search for novel biomarkers for personalised therapy, we determined the prognostic impact of stromal markers, hypoxia and neovascularity in high-grade soft tissue leiomyos......BACKGROUND AND AIM: Sarcomas are of mesenchymal origin and typically show abundant tumour stroma and presence of necrosis. In search for novel biomarkers for personalised therapy, we determined the prognostic impact of stromal markers, hypoxia and neovascularity in high-grade soft tissue...... leiomyosarcoma and pleomorphic undifferentiated sarcoma. METHOD: We evaluated CD163, colony-stimulating factor (CSF)-1, CD16 and hypoxia-inducible factor 1 (HIF-1)α using immunohistochemical staining and assessed microvessel density using CD31 in 73 high-grade leiomyosarcomas and undifferentiated pleomorphic...... sarcomas of the extremities and the trunk wall. The results were correlated to metastasis-free and overall survival. RESULTS: Expression of HIF-1α was associated with the presence of necrosis and independently predicted shorter metastasis-free survival (HR 3.2, CI 1.4 to 7.0, p=0.004), whereas neither...

  3. Tariquidar sensitizes multiple myeloma cells to proteasome inhibitors via reduction of hypoxia-induced P-gp-mediated drug resistance.

    Science.gov (United States)

    Muz, Barbara; Kusdono, Hubert D; Azab, Feda; de la Puente, Pilar; Federico, Cinzia; Fiala, Mark; Vij, Ravi; Salama, Noha N; Azab, Abdel Kareem

    2017-12-01

    Multiple myeloma (MM) presents a poor prognosis and high lethality of patients due to development of drug resistance. P-glycoprotein (P-gp), a drug-efflux transporter, is upregulated in MM patients post-chemotherapy and is involved in the development of drug resistance since many anti-myeloma drugs (including proteasome inhibitors) are P-gp substrates. Hypoxia develops in the bone marrow niche during MM progression and has long been linked to chemoresistance. Additionally, hypoxia-inducible transcription factor (HIF-1α) was demonstrated to directly regulate P-gp expression. We found that in MM patients P-gp expression positively correlated with the hypoxic marker, HIF-1α. Hypoxia increased P-gp protein expression and its efflux capabilities in MM cells in vitro using flow cytometry. We reported herein that hypoxia-mediated resistance to carfilzomib and bortezomib in MM cells is due to P-gp activity and was reversed by tariquidar, a P-gp inhibitor. These results suggest combining proteasome inhibitors with P-gp inhibition for future clinical studies.

  4. Molecular cloning and characterization of the Xenopus hypoxia-inducible factor 1alpha (xHIF1alpha).

    Science.gov (United States)

    de Beaucourt, Arnaud; Coumailleau, Pascal

    2007-12-15

    We report the molecular cloning and the characterization of the Xenopus homolog of mammalian hypoxia-inducible factor 1alpha (HIF1alpha), a member of the bHLH/PAS transcription factor family. Searches in Xenopus genome sequences and phylogenetic analysis reveal the existence of HIF1alpha and HIF2alpha paralogs in the Xenopus laevis species. Sequence data analyses indicate that the organization of protein domains in Xenopus HIF1alpha (xHIF1alpha) is strongly conserved. We also show that xHIF1alpha heterodimerizes with the Xenopus Arnt1 protein (xArnt1) with the proteic complex being mediated by the HLH and PAS domains. Subcellular analysis in a Xenopus XTC cell line using chimeric GFP constructs show that over-expression of xHIF1alpha and xArnt1 allows us to detect the xHIF1alpha/xArnt1 complex in the nucleus, but only in the presence of both partners. Further analyses in XTC cell line show that over-producing xHIF1alpha and xArnt1 mediates trans-activation of the hypoxia response element (HRE) reporter. The trans-activation level can be increased in hypoxia conditions. Interestingly such trans-activation properties can be also observed when human Arnt1 is used together with the xHIF1alpha. Copyright (c) 2007 Wiley-Liss, Inc.

  5. The function of hypoxia-inducible factor (HIF is independent of the endoplasmic reticulum protein OS-9.

    Directory of Open Access Journals (Sweden)

    Ulf Brockmeier

    Full Text Available The protein "amplified in osteosarcoma-9" (OS-9 has been shown previously to interact with the prolyl hydroxylases PHD2 and PHD3. These enzymes initiate oxygen-dependent degradation of the α-subunit of hypoxia-inducible factor (HIF, a transcription factor that adapts cells to insufficient oxygen supply (hypoxia. A new model has been proposed where OS-9 triggers PHD dependent degradation of HIF-α. It was the aim of our study to define the molecular mode of action of OS-9 in the regulation of PHD and HIF activity. Although initial co-immunoprecipitation experiments confirmed physical interaction between OS-9 and PHD2, neither overexpression nor lentiviral inhibition of OS-9 expression affected HIF regulation. Subcellular localization experiments revealed a distinct reticular staining pattern for OS-9 while PHD2 was mainly localized in the cytoplasm. Further cell fractionation experiments and glycosylation tests indicated that OS-9 is a luminal ER protein. In vivo protein interaction analysis by fluorescence resonance energy transfer (FRET showed no significant physical interaction of overexpressed PHD2-CFP and OS-9-YFP. We conclude that OS-9 plays no direct functional role in HIF degradation since physical interaction of OS-9 with oxygen sensing HIF prolyl hydroxylases cannot occur in vivo due to their different subcellular localization.

  6. Expression of hypoxia-inducible factor-1α during ovarian follicular growth and development in Sprague-Dawley rats.

    Science.gov (United States)

    Zhang, Z H; Chen, L Y; Wang, F; Wu, Y Q; Su, J Q; Huang, X H; Wang, Z C; Cheng, Y

    2015-06-01

    Hypoxia-inducible factor-1α (HIF-1α) has been identified as a transcription factor that is involved in diverse physiological and pathological processes in the ovary. In this study, we examined whether HIF-1α is expressed in a cell- and stage-specific manner during follicular growth and development in the mammalian ovaries. Using immunohistochemistry and Western blot analysis, HIF-1α expression was observed in granulosa cells specifically and was significantly increased during the follicular growth and development of postnatal rats. Furthermore, pregnant mare serum gonadotropin also induced HIF-1α expression in granulosa cells and ovaries during the follicular development of immature rats primed with gonadotropin. Moreover, we also examined proliferation cell nuclear antigen, a cell proliferation marker, during follicular growth and development and found that its expression pattern was similar to that of HIF-1α protein. Granulosa cell culture experiments revealed that proliferation cell nuclear antigen expression may be regulated by HIF-1α. These results indicated that HIF-1α plays an important role in the follicular growth and development of these 2 rat models. The HIF-1α-mediated signaling pathway may be an important mechanism regulating follicular growth and development in mammalian ovaries in vivo.

  7. Graviola inhibits hypoxia-induced NADPH oxidase activity in prostate cancer cells reducing their proliferation and clonogenicity

    Science.gov (United States)

    Deep, Gagan; Kumar, Rahul; Jain, Anil K.; Dhar, Deepanshi; Panigrahi, Gati K.; Hussain, Anowar; Agarwal, Chapla; El-Elimat, Tamam; Sica, Vincent P.; Oberlies, Nicholas H.; Agarwal, Rajesh

    2016-01-01

    Prostate cancer (PCa) is the leading malignancy among men. Importantly, this disease is mostly diagnosed at early stages offering a unique chemoprevention opportunity. Therefore, there is an urgent need to identify and target signaling molecules with higher expression/activity in prostate tumors and play critical role in PCa growth and progression. Here we report that NADPH oxidase (NOX) expression is directly associated with PCa progression in TRAMP mice, suggesting NOX as a potential chemoprevention target in controlling PCa. Accordingly, we assessed whether NOX activity in PCa cells could be inhibited by Graviola pulp extract (GPE) that contains unique acetogenins with strong anti-cancer effects. GPE (1–5 μg/ml) treatment strongly inhibited the hypoxia-induced NOX activity in PCa cells (LNCaP, 22Rv1 and PC3) associated with a decrease in the expression of NOX catalytic and regulatory sub-units (NOX1, NOX2 and p47phox). Furthermore, GPE-mediated NOX inhibition was associated with a strong decrease in nuclear HIF-1α levels as well as reduction in the proliferative and clonogenic potential of PCa cells. More importantly, GPE treatment neither inhibited NOX activity nor showed any cytotoxicity against non-neoplastic prostate epithelial PWR-1E cells. Overall, these results suggest that GPE could be useful in the prevention of PCa progression via inhibiting NOX activity. PMID:26979487

  8. Chronic hypoxia-inducible transcription factor-2 activation stably transforms juxtaglomerular renin cells into fibroblast-like cells in vivo.

    Science.gov (United States)

    Kurt, Birguel; Gerl, Katharina; Karger, Christian; Schwarzensteiner, Ilona; Kurtz, Armin

    2015-03-01

    On the basis of previous observations that deletion of the von Hippel-Lindau protein (pVHL) in juxtaglomerular (JG) cells of the kidney suppresses renin and induces erythropoietin expression, this study aimed to characterize the events underlying this striking change of hormone expression. We found that renin cell-specific deletion of pVHL in mice leads to a phenotype switch in JG cells, from a cuboid and multiple vesicle-containing form into a flat and elongated form without vesicles. This shift of cell phenotype was accompanied by the disappearance of marker proteins for renin cells (e.g., aldo-keto reductase family 1, member 7 and connexin 40) and by the appearance of markers of fibroblast-like cells (e.g., collagen I, ecto-5'-nucleotidase, and PDGF receptor-β). Furthermore, hypoxia-inducible transcription factor-2α (HIF-2α) protein constitutively accumulated in these transformed cells. Codeletion of pVHL and HIF-2α in JG cells completely prevented the phenotypic changes. Similar to renin expression in normal JG cells, angiotensin II negatively regulated erythropoietin expression in the transformed cells. In summary, chronic activation of HIF-2 in renal JG cells leads to a reprogramming of the cells into fibroblast-like cells resembling native erythropoietin-producing cells located in the tubulointerstitium. Copyright © 2015 by the American Society of Nephrology.

  9. Hypoxia-inducible factor-1α perpetuates synovial fibroblast interactions with T cells and B cells in rheumatoid arthritis.

    Science.gov (United States)

    Hu, Fanlei; Liu, Hongjiang; Xu, Liling; Li, Yingni; Liu, Xu; Shi, Lianjie; Su, Yin; Qiu, Xiaoyan; Zhang, Xia; Yang, Yuqin; Zhang, Jian; Li, Zhanguo

    2016-03-01

    Synovial fibroblast hyperplasia, T-cell hyperactivity, B-cell overactivation, and the self-perpetuating interactions among these cell types are major characteristics of rheumatoid arthritis (RA). The inflamed joints of RA patients are hypoxic, with upregulated expression of hypoxia-inducible factor-1α (HIF-1α) in RA synovial fibroblasts (RASFs). It remains unknown whether HIF-1α regulates interactions between RASFs and T cells and B cells. We report here that HIF-1α promotes the expression of inflammatory cytokines IL-6, IL-8, TNF-α, and IL-1β, and cell-cell contact mediators IL-15, vascular cell adhesion molecule (VCAM)-1, thrombospondin (TSP)-1, and stromal cell-derived factor (SDF)-1 in RASFs. Furthermore, HIF-1α perpetuates RASF-mediated inflammatory Th1- and Th17-cell expansion while differentially inhibiting regulatory B10 and innate-like B cells, leading to increased IFN-γ, IL-17, and IgG production and decreased protective natural IgM secretion. Our findings suggest that HIF-1α perpetuates the interactions between RASFs and T cells and B cells to induce inflammatory cytokine and autoantibody production, thus exacerbating the severity of RA. Targeting HIF-1α may provide new therapeutic strategies for overcoming this persistent disease. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Ubiquitination is absolutely required for the degradation of hypoxia-inducible factor - 1 alpha protein in hypoxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ronghai [Department of Urology, Linzi District People' s Hospital, Zibo, 255400 (China); Zhang, Ping, E-mail: zpskx001@163.com [Department of Gynecology, Qingdao Municipal Hospital, Qingdao, 266011 (China); Li, Jinhang [Department of Gynecology, Qingdao Municipal Hospital, Qingdao, 266011 (China); Guan, Hongzai [Laboratory Department, School of Medicine, Qingdao University, Qingdao, 266071 (China); Shi, Guangjun, E-mail: qdmhshigj@yahoo.com [Department of Hepatobiliary Surgery, Qingdao Municipal Hospital, Qingdao, 266071 (China)

    2016-01-29

    The hypoxia-inducible factor (HIF) is recognized as the master regulator of hypoxia response. HIF-α subunits expression are tightly regulated. In this study, our data show that ts20 cells still expressed detectable E1 protein even at 39.5° C for 12 h, and complete depletion of E1 protein expression at 39.5° C by siRNA enhanced HIF-1α and P53 protein expression. Further inhibition of E1 at 39.5 °C by siRNA, or E1 inhibitor Ube1-41 completely blocked HIF-1α degradation. Moreover, immunoprecipitations of co-transfection of HA-ubiquitin and FLAG–HIF–1α plasmids directly confirmed the involvement of ubiquitin in the hypoxic degradation of HIF-1α. Additionally, hypoxic HIF-1 α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization. Taken together, our data suggest that constitutive HIF-1α protein degradation in hypoxia is absolutely ubiquitination-dependent, and unidentified E3 ligase may exist for this degradation pathway. - Highlights: • HIF-1α protein is constitutively degraded in hypoxic conditions. • Requirement of ubiquitination for HIF-1α degradation in hypoxia. • Hypoxic HIF-1α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization.

  11. Isolation of hypoxia-inducible factor 1 (HIF-1) inhibitors from frankincense using a molecularly imprinted polymer.

    Science.gov (United States)

    Lakka, Achillia; Mylonis, Ilias; Bonanou, Sophia; Simos, George; Tsakalof, Andreas

    2011-10-01

    Hypoxia-Inducible Factor 1 (HIF-1), a transcriptional activator, is highly involved in the pathology of cancer. Inhibition of HIF-1 retards tumor growth and enhances treatment efficiency when used in combination with chemo- or radiation therapy. The recent validation of HIF-1 as an important drug target in cancer treatment has stimulated efforts to identify and isolate natural or synthetic HIF-1 inhibitors. In the present study, quercetin, a known inhibitor of HIF-1, was imprinted in a polymer matrix in order to prepare a Molecularly Imprinted Polymer (MIP), which was subsequently used for the selective isolation of new inhibitors from frankincense, a gum resin used as anticancer remedy in traditional medicine. The frankincense components isolated by Solid Phase Extraction on MIP (MIP-SPE), efficiently inhibited the transcriptional activity of HIF-1 and decreased the protein levels of HIF-1α, the regulated subunit of HIF-1. The selective retention of acetyl 11-ketoboswellic acid (AKBA, one of the main bioactive components of frankincense) by MIP led to the revealing of its inhibitory activity on the HIF-1 signaling pathway. AKBA was selectively retained by SPE on the quercetin imprinted polymer, with an imprinting effect of 8.1 ± 4.6. Overall, this study demonstrates the potential of MIP application in the screening, recognition and isolation of new bioactive compounds that aim selected molecular targets, a potential that has been poorly appreciated until.

  12. Hypoxia-inducible factors regulate pluripotency factor expression by ZNF217- and ALKBH5-mediated modulation of RNA methylation in breast cancer cells.

    Science.gov (United States)

    Zhang, Chuanzhao; Zhi, Wanqing Iris; Lu, Haiquan; Samanta, Debangshu; Chen, Ivan; Gabrielson, Edward; Semenza, Gregg L

    2016-10-04

    Exposure of breast cancer cells to hypoxia increases the percentage of breast cancer stem cells (BCSCs), which are required for tumor initiation and metastasis, and this response is dependent on the activity of hypoxia-inducible factors (HIFs). We previously reported that exposure of breast cancer cells to hypoxia induces the ALKBH5-mediated demethylation of N6-methyladenosine (m6A) in NANOG mRNA leading to increased expression of NANOG, which is a pluripotency factor that promotes BCSC specification. Here we report that exposure of breast cancer cells to hypoxia also induces ZNF217-dependent inhibition of m6A methylation of mRNAs encoding NANOG and KLF4, which is another pluripotency factor that mediates BCSC specification. Although hypoxia induced the BCSC phenotype in all breast-cancer cell lines analyzed, it did so through variable induction of pluripotency factors and ALKBH5 or ZNF217. However, in every breast cancer line, the hypoxic induction of pluripotency factor and ALKBH5 or ZNF217 expression was HIF-dependent. Immunohistochemistry revealed that expression of HIF-1α and ALKBH5 was concordant in all human breast cancer biopsies analyzed. ALKBH5 knockdown in MDA-MB-231 breast cancer cells significantly decreased metastasis from breast to lungs in immunodeficient mice. Thus, HIFs stimulate pluripotency factor expression and BCSC specification by negative regulation of RNA methylation.

  13. The hypoxia-inducible factor-responsive proteins semaphorin 4D and vascular endothelial growth factor promote tumor growth and angiogenesis in oral squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hua; Yang, Ying-Hua [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Binmadi, Nada O. [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Department of Oral Basic and Clinical Sciences, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Proia, Patrizia [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Department of Sports Science (DISMOT), University of Palermo, Via Eleonora Duse 2 90146, Palermo (Italy); Basile, John R., E-mail: jbasile@umaryland.edu [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Greenebaum Cancer Center, 22S. Greene Street, Baltimore, MD 21201 (United States)

    2012-08-15

    Growth and metastasis of solid tumors requires induction of angiogenesis to ensure the delivery of oxygen, nutrients and growth factors to rapidly dividing transformed cells. Through either mutations, hypoxia generated by cytoreductive therapies, or when a malignancy outgrows its blood supply, tumor cells undergo a change from an avascular to a neovascular phenotype, a transition mediated by the hypoxia-inducible factor (HIF) family of transcriptional regulators. Vascular endothelial growth factor (VEGF) is one example of a gene whose transcription is stimulated by HIF. VEGF plays a crucial role in promoting tumor growth and survival by stimulating new blood vessel growth in response to such stresses as chemotherapy or radiotherapy-induced hypoxia, and it therefore has become a tempting target for neutralizing antibodies in the treatment of advanced neoplasms. Emerging evidence has shown that the semaphorins, proteins originally associated with control of axonal growth and immunity, are regulated by changes in oxygen tension as well and may play a role in tumor-induced angiogenesis. Through the use of RNA interference, in vitro and in vivo angiogenesis assays and tumor xenograft experiments, we demonstrate that expression of semaphorin 4D (SEMA4D), which is under the control of the HIF-family of transcription factors, cooperates with VEGF to promote tumor growth and vascularity in oral squamous cell carcinoma (OSCC). We use blocking antibodies to show that targeting SEMA4D function along with VEGF could represent a novel anti-angiogenic therapeutic strategy for the treatment of OSCC and other solid tumors. -- Highlights: Black-Right-Pointing-Pointer Similar to VEGF, SEMA4D promotes angiogenesis in vitro and in vivo. Black-Right-Pointing-Pointer Both VEGF and SEMA4D are produced by OSCC cells in a HIF-dependent manner. Black-Right-Pointing-Pointer These factors combine to elicit a robust pro-angiogenic phenotype in OSCC. Black-Right-Pointing-Pointer Anti-SEMA4D

  14. Hypoxia Inducible Factor-1α in Astrocytes and/or Myeloid Cells Is Not Required for the Development of Autoimmune Demyelinating Disease(,.)

    Science.gov (United States)

    Le Moan, Natacha; Baeten, Kim M; Rafalski, Victoria A; Ryu, Jae Kyu; Rios Coronado, Pamela E; Bedard, Catherine; Syme, Catriona; Davalos, Dimitrios; Akassoglou, Katerina

    2015-01-01

    Hypoxia-like tissue alterations, characterized by the upregulation of hypoxia-inducible factor-1α (HIF-1α), have been described in the normal appearing white matter and pre-demyelinating lesions of multiple sclerosis (MS) patients. As HIF-1α regulates the transcription of a wide set of genes involved in neuroprotection and neuroinflammation, HIF-1α expression may contribute to the pathogenesis of inflammatory demyelination. To test this hypothesis, we analyzed the effect of cell-specific genetic ablation or overexpression of HIF-1α on the onset and progression of experimental autoimmune encephalomyelitis (EAE), a mouse model for MS. HIF-1α was mainly expressed in astrocytes and microglia/macrophages in the mouse spinal cord at the peak of EAE. However, genetic ablation of HIF-1α in astrocytes and/or myeloid cells did not ameliorate clinical symptoms. Furthermore, conditional knock-out of Von Hippel Lindau, a negative regulator of HIF-1α stabilization, failed to exacerbate the clinical course of EAE. In accordance with clinical symptoms, genetic ablation or overexpression of HIF-1α did not change the extent of spinal cord inflammation and demyelination. Overall, our data indicate that despite dramatic upregulation of HIF-1α in astrocytes and myeloid cells in EAE, HIF-1α expression in these two cell types is not required for the development of inflammatory demyelination. Despite numerous reports indicating HIF-1α expression in glia, neurons, and inflammatory cells in the CNS of MS patients, the cell-specific contribution of HIF-1α to disease pathogenesis remains unclear. Here we show that although HIF-1α is dramatically upregulated in astrocytes and myeloid cells in EAE, cell-specific depletion of HIF-1α in these two cell types surprisingly does not affect the development of neuroinflammatory disease. Together with two recently published studies showing a role for oligodendrocyte-specific HIF-1α in myelination and T-cell-specific HIF-1α in EAE, our

  15. Sirtuin 6 suppresses hypoxia-induced inflammatory response in human osteoblasts via inhibition of reactive oxygen species production and glycolysis-A therapeutic implication in inflammatory bone resorption.

    Science.gov (United States)

    Hou, Kuo-Liang; Lin, Sze-Kwan; Chao, Ling-Hsiu; Hsiang-Hua Lai, Eddie; Chang, Cheng-Chi; Shun, Chia-Tung; Lu, Wan-Yu; Wang, Jyh-Horng; Hsiao, Michael; Hong, Chi-Yuan; Kok, Sang-Heng

    2017-03-01

    Elevated glycolytic activity and redox imbalance induced by tissue hypoxia are common phenomena of chronic inflammation, including inflammatory bone diseases such as arthritis. However, relation between glycolysis and redox signaling in the inflammatory milieu is unclear. The histone deacetylase sirtuin 6 (SIRT6) is a crucial modulator of inflammation and glucose metabolism, and it is also involved in cellular protection against oxidative injury. The aims of the study were to examine the connection between glycolysis and reactive oxygen species (ROS) production in human osteoblastic cells (HOB) and whether SIRT6 modulates inflammatory response via regulation of glycolytic activity and ROS generation. In HOB cultured under hypoxia, expression of lactate dehydrogenase A (LDHA), lactate production and ROS generation were examined. The reciprocal effects between lactate and ROS production and their impact on inflammatory cytokine induction were assessed. The action of SIRT6 on the above reactions was determined. In a rat model of collagen-induced arthritis (CIA), the relation between inflammatory activity and osteoblastic expression of LDHA, level of oxidative lesions, Cyr61 synthesis and macrophage recruitment were examined in joints with or without lentiviral-SIRT6 gene therapy. Results showed that hypoxia stress enhanced lactate and LDHA production in HOB. ROS generation was also increased, and there was a positive feedback between glycolysis and ROS formation. Overexpression of SIRT6 attenuated hypoxia-enhanced glycolysis and ROS generation. Hypoxia-induced expressions of Cyr61, TNF-α, IL-1β, and IL-6 were suppressed by SIRT6 and the inhibitory effects overlapped with antiglycolytic and antioxidation mechanisms. In the model of CIA, forced expression of SIRT6 ameliorated disease progression, osteoblastic synthesis of Cyr61, and macrophage recruitment. More importantly, expression of LDHA and oxidative lesions were decreased in osteoblasts of SIRT6-treated joints

  16. Proteomic identification of novel differentiation plasma protein markers in hypobaric hypoxia-induced rat model.

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    Yasmin Ahmad

    Full Text Available Hypobaric hypoxia causes complex changes in the expression of genes, including stress related genes and corresponding proteins that are necessary to maintain homeostasis. Whereas most prior studies focused on single proteins, newer methods allowing the simultaneous study of many proteins could lead to a better understanding of complex and dynamic changes that occur during the hypobaric hypoxia.In this study we investigated the temporal plasma protein alterations of rat induced by hypobaric hypoxia at a simulated altitude of 7620 m (25,000 ft, 282 mm Hg in a hypobaric chamber. Total plasma proteins collected at different time points (0, 6, 12 and 24 h, separated by two-dimensional electrophoresis (2-DE and identified using matrix assisted laser desorption ionization time of flight (MALDI-TOF/TOF. Biological processes that were enriched in the plasma proteins during hypobaric hypoxia were identified using Gene Ontology (GO analysis. According to their properties and obvious alterations during hypobaric hypoxia, changes of plasma concentrations of Ttr, Prdx-2, Gpx -3, Apo A-I, Hp, Apo-E, Fetub and Nme were selected to be validated by Western blot analysis.Bioinformatics analysis of 25 differentially expressed proteins showed that 23 had corresponding candidates in the database. The expression patterns of the eight selected proteins observed by Western blot were in agreement with 2-DE results, thus confirming the reliability of the proteomic analysis. Most of the proteins identified are related to cellular defense mechanisms involving anti-inflammatory and antioxidant activity. Their presence reflects the consequence of serial cascades initiated by hypobaric hypoxia.This study provides information about the plasma proteome changes induced in response to hypobaric hypoxia and thus identification of the candidate proteins which can act as novel biomarkers.

  17. Hypoxia-Inducible Factor-1α Expression in Macrophages Promotes Development of Atherosclerosis

    DEFF Research Database (Denmark)

    Pedersen, Annemarie Aarup; Pedersen, Tanja X; Junker, Nanna

    2016-01-01

    transplanted with bone marrow from mice with HIF-1α deficiency in the myeloid cells or control bone marrow. The HIF-1α deficiency in myeloid cells reduced atherosclerosis in aorta of the Ldlr(-/-) recipient mice by ≈72% (P=0.006).In vitro, HIF-1α-deficient macrophages displayed decreased differentiation...... to proinflammatory M1 macrophages and reduced expression of inflammatory genes. HIF-1α deficiency also affected glucose uptake, apoptosis, and migratory abilities of the macrophages. CONCLUSIONS: HIF-1α expression in macrophages affects their intrinsic inflammatory profile and promotes development of atherosclerosis....

  18. Putative role of ischemic postconditioning in a rat model of limb ischemia and reperfusion: involvement of hypoxia-inducible factor-1α expression

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T. [Department of Anesthesiology, Shuyang People' s Hospital, JiangSu (China); Zhou, Y.T. [Department of General Surgery, Shuyang People' s Hospital, JiangSu (China); Chen, X.N. [Institute of Pathophysiology, School of Basic Medical Sciences, LanZhou University, Lanzhou, Gansu (China); Zhu, A.X. [Department of Pharmacy, Shuyang People' s Hospital, JiangSu (China)

    2014-07-25

    Hypoxia-inducible factor-1α (HIF-1α) is one of the most potent angiogenic growth factors. It improves angiogenesis and tissue perfusion in ischemic skeletal muscle. In the present study, we tested the hypothesis that ischemic postconditioning is effective for salvaging ischemic skeletal muscle resulting from limb ischemia-reperfusion injury, and that the mechanism involves expression of HIF-1α. Wistar rats were randomly divided into three groups (n=36 each): sham-operated (group S), hindlimb ischemia-reperfusion (group IR), and ischemic postconditioning (group IPO). Each group was divided into subgroups (n=6) according to reperfusion time: immediate (0 h, T{sub 0}), 1 h (T{sub 1}), 3 h (T{sub 3}), 6 h (T{sub 6}), 12 h (T{sub 12}), and 24 h (T{sub 24}). In the IPO group, three cycles of 30-s reperfusion and 30-s femoral aortic reocclusion were carried out before reperfusion. At all reperfusion times (T{sub 0}-T{sub 24}), serum creatine kinase (CK) and lactate dehydrogenase (LDH) activities, as well as interleukin (IL)-6, IL-10, and tumor necrosis factor-α (TNF-α) concentrations, were measured in rats after they were killed. Histological and immunohistochemical methods were used to assess the skeletal muscle damage and HIF-1α expression in skeletal muscle ischemia. In groups IR and IPO, serum LDH and CK activities and TNF-α, IL-6, and IL-10 concentrations were all significantly increased compared to group S, and HIF-1α expression was up-regulated (P<0.05 or P<0.01). In group IPO, serum LDH and CK activities and TNF-α and IL-6 concentrations were significantly decreased, IL-10 concentration was increased, HlF-1α expression was down-regulated (P<0.05 or P<0.01), and the pathological changes were reduced compared to group IR. The present study suggests that ischemic postconditioning can reduce skeletal muscle damage caused by limb ischemia-reperfusion and that its mechanisms may be related to the involvement of HlF-1α in the limb ischemia-reperfusion injury

  19. Putative role of ischemic postconditioning in a rat model of limb ischemia and reperfusion: involvement of hypoxia-inducible factor-1? expression

    Directory of Open Access Journals (Sweden)

    T. Wang

    2014-09-01

    Full Text Available Hypoxia-inducible factor-1α (HIF-1α is one of the most potent angiogenic growth factors. It improves angiogenesis and tissue perfusion in ischemic skeletal muscle. In the present study, we tested the hypothesis that ischemic postconditioning is effective for salvaging ischemic skeletal muscle resulting from limb ischemia-reperfusion injury, and that the mechanism involves expression of HIF-1α. Wistar rats were randomly divided into three groups (n=36 each: sham-operated (group S, hindlimb ischemia-reperfusion (group IR, and ischemic postconditioning (group IPO. Each group was divided into subgroups (n=6 according to reperfusion time: immediate (0 h, T0, 1 h (T1, 3 h (T3, 6 h (T6, 12 h (T12, and 24 h (T24. In the IPO group, three cycles of 30-s reperfusion and 30-s femoral aortic reocclusion were carried out before reperfusion. At all reperfusion times (T0-T24, serum creatine kinase (CK and lactate dehydrogenase (LDH activities, as well as interleukin (IL-6, IL-10, and tumor necrosis factor-α (TNF-α concentrations, were measured in rats after they were killed. Histological and immunohistochemical methods were used to assess the skeletal muscle damage and HIF-1α expression in skeletal muscle ischemia. In groups IR and IPO, serum LDH and CK activities and TNF-α, IL-6, and IL-10 concentrations were all significantly increased compared to group S, and HIF-1α expression was up-regulated (P<0.05 or P<0.01. In group IPO, serum LDH and CK activities and TNF-α and IL-6 concentrations were significantly decreased, IL-10 concentration was increased, HlF-1α expression was down-regulated (P<0.05 or P<0.01, and the pathological changes were reduced compared to group IR. The present study suggests that ischemic postconditioning can reduce skeletal muscle damage caused by limb ischemia-reperfusion and that its mechanisms may be related to the involvement of HlF-1α in the limb ischemia-reperfusion injury-triggered inflammatory response.

  20. Angiotensin II type 1 receptor blockade partially attenuates hypoxia-induced pulmonary hypertension in newborn piglets: relationship with the nitrergic system

    Energy Technology Data Exchange (ETDEWEB)

    Camelo, J.S. Jr. [Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Martins, A.R. [Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Instituto de Ciências Biológicas, Universidade Federal do Triângulo Mineiro, Uberaba, MG (Brazil); Rosa, E. [Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Ramos, S.G. [Departamento de Patologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SPBrasil (Brazil); Hehre, D.; Bancalari, E.; Suguihara, C. [Department of Pediatrics, Division of Neonatology, Neonatal Developmental Biology Laboratory, University of Miami Miller School of Medicine, Miami, FL (United States)

    2012-02-10

    The objective of this study was to observe possible interactions between the renin-angiotensin and nitrergic systems in chronic hypoxia-induced pulmonary hypertension in newborn piglets. Thirteen chronically instrumented newborn piglets (6.3 ± 0.9 days; 2369 ± 491 g) were randomly assigned to receive saline (placebo, P) or the AT{sub 1} receptor (AT{sub 1}-R) blocker L-158,809 (L) during 6 days of hypoxia (FiO{sub 2} = 0.12). During hypoxia, pulmonary arterial pressure (Ppa; P < 0.0001), pulmonary vascular resistance (PVR; P < 0.02) and the pulmonary to systemic vascular resistance ratio (PVR/SVR; P < 0.05) were significantly attenuated in the L (N = 7) group compared to the P group (N = 6). Western blot analysis of lung proteins showed a significant decrease of endothelial NOS (eNOS) in both P and L animals, and of AT{sub 1}-R in P animals during hypoxia compared to normoxic animals (C group, N = 5; P < 0.01 for all groups). AT{sub 1}-R tended to decrease in L animals. Inducible NOS (iNOS) did not differ among P, L, and C animals and iNOS immunohistochemical staining in macrophages was significantly more intense in L than in P animals (P < 0.01). The vascular endothelium showed moderate or strong eNOS and AT{sub 1}-R staining. Macrophages and pneumocytes showed moderate or strong iNOS and AT{sub 1}-R staining, but C animals showed weak iNOS and AT{sub 1}-R staining. Macrophages of L and P animals showed moderate and weak AT{sub 2}-R staining, respectively, but the endothelium of all groups only showed weak staining. In conclusion, pulmonary hypertension induced by chronic hypoxia in newborn piglets is partially attenuated by AT{sub 1}-R blockade. We suggest that AT{sub 1}-R blockade might act through AT{sub 2}-R and/or Mas receptors and the nitrergic system in the lungs of hypoxemic newborn piglets.

  1. Metallothionein as a compensatory component prevents intermittent hypoxia-induced cardiomyopathy in mice

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Xia; Zhou, Shanshan [The First Hospital of Jilin University, Changchun, 130021 (China); KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Zheng, Yang, E-mail: zhengyang@jlu.edu.cn [The First Hospital of Jilin University, Changchun, 130021 (China); Tan, Yi [KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Chinese–American Research Institute for Diabetic Complications, Wenzhou Medical College School of Pharmacy, Wenzhou, 325035 (China); Kong, Maiying [Department of Bioinformatics and Biostatistics, School of Public Health and Information Sciences, University of Louisville, Louisville, KY 40202 (United States); Wang, Bo [KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Department of Pathology, Inner Mongolia Forestry General Hospital, Yakeshi, 022150 (China); Feng, Wenke [Department of Medicine, School of Medicine, University of Louisville, Louisville, 40202 (United States); Epstein, Paul N. [KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Cai, Jun, E-mail: j0cai002@louisville.edu [KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Cai, Lu [KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Chinese–American Research Institute for Diabetic Complications, Wenzhou Medical College School of Pharmacy, Wenzhou, 325035 (China); Department of Medicine, School of Medicine, University of Louisville, Louisville, 40202 (United States)

    2014-05-15

    Obstructive sleep apnea (OSA) causes chronic intermittent hypoxia (IH) to induce cardiovascular disease, which may be related to oxidative damage. Metallothionein (MT) has been extensively proved to be an endogenous and highly inducible antioxidant protein expressed in the heart. Therefore, we tested the hypotheses that oxidative stress plays a critical role in OSA induced cardiac damage and MT protects the heart from OSA-induced cardiomyopathy. To mimic hypoxia/reoxygenation events that occur in adult OSA patients, mice were exposed to IH for 3 days to 8 weeks. The IH paradigm consisted of alternating cycles of 20.9% O{sub 2}/8% O{sub 2} F{sub I}O{sub 2} (30 episodes per hour) with 20 s at the nadir F{sub I}O{sub 2} for 12 h a day during daylight. IH significantly increased the ratio of heart weight to tibia length at 4 weeks with a decrease in cardiac function from 4 to 8 weeks. Cardiac oxidative damage and fibrosis were observed after 4 and 8 weeks of IH exposures. Endogenous MT expression was up-regulated in response to 3-day IH, but significantly decreased at 4 and 8 weeks of IH. In support of MT as a major compensatory component, mice with cardiac overexpression of MT gene and mice with global MT gene deletion were completely resistant, and highly sensitive, respectively, to chronic IH induced cardiac effects. These findings suggest that chronic IH induces cardiomyopathy characterized by oxidative stress-mediated cardiac damage and the antioxidant MT protects the heart from such pathological and functional changes. - Highlights: • The effect of intermittent hypoxia (IH) on cardiac metallothionein (MT) • Cardiac MT expression was up-regulated in response to 3-day IH. • Exposure to 4- or 8-week IH downregulated cardiac MT expression. • Overexpression of cardiac MT protects from IH-induced cardiac damage. • Global deletion of MT gene made the heart more sensitive to IH damage.

  2. Comparative and functional analysis of cardiovascular-related genes

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Jan-Fang; Pennacchio, Len A.

    2003-09-01

    The ability to detect putative cis-regulatory elements in cardiovascular-related genes has been accelerated by the availability of genomic sequence data from numerous vertebrate species and the recent development of comparative genomic tools. This improvement is anticipated to lead to a better understanding of the complex regulatory architecture of cardiovascular (CV) genes and how genetic variants in these non-coding regions can potentially play a role in cardiovascular disease. This manuscript reviews a recently established database dedicated to the comparative sequence analysis of 250 human CV genes of known importance, 37 of which currently contain sequence comparison data for organisms beyond those of human, mouse and rat. These data have provided a glimpse into the variety of possible insights from deep vertebrate sequence comparisons and the identification of putative gene regulatory elements.

  3. Temporo-spectral imaging of intrinsic optical signals during hypoxia-induced spreading depression-like depolarization.

    Directory of Open Access Journals (Sweden)

    Maria Mané

    Full Text Available Spreading depression (SD is characterized by a sustained near-complete depolarization of neurons, a massive depolarization of glia, and a negative deflection of the extracellular DC potential. These electrophysiological signs are accompanied by an intrinsic optical signal (IOS which arises from changes in light scattering and absorption. Even though the underlying mechanisms are unclear, the IOS serves as non-invasive tool to define the spatiotemporal dynamics of SD in brain slices. Usually the tissue is illuminated by white light, and light reflectance or transmittance is monitored. Using a polychromatic, fast-switchable light source we now performed temporo-spectral recordings of the IOS associated with hypoxia-induced SD-like depolarization (HSD in rat hippocampal slices kept in an interface recording chamber. Recording full illumination spectra (320-680 nm yielded distinct reflectance profiles for the different phases of HSD. Early during hypoxia tissue reflectance decreased within almost the entire spectrum due to cell swelling. HSD was accompanied by a reversible reflectance increase being most pronounced at 400 nm and 460 nm. At 440 nm massive porphyrin absorption (Soret band was detected. Hypotonic solutions, Ca(2+-withdrawal and glial poisoning intensified the reflectance increase during HSD, whereas hypertonic solutions dampened it. Replacement of Cl(- inverted the reflectance increase. Inducing HSD by cyanide distorted the IOS and reflectance at 340-400 nm increased irreversibly. The pronounced changes at short wavelengths (380 nm, 460 nm and their cyanide sensitivity suggest that block of mitochondrial metabolism contributes to the IOS during HSD. For stable and reliable IOS recordings during HSD wavelengths of 460-560 nm are recommended.

  4. Knock-down of hypoxia-induced carbonic anhydrases IX and XII radiosensitizes tumor cells by increasing intracellular acidosis

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    Jérôme eDoyen

    2013-01-01

    Full Text Available The relationship between acidosis within the tumor microenvironment and radioresistance of hypoxic tumor cells remains unclear. Previously we reported that hypoxia-induced carbonic anhydrases CAIX and CAXII constitute a robust pHi-regulating system that confers a survival advantage on hypoxic human colon carcinoma LS174Tr cells in acidic microenvironments. Here we investigate the role of acidosis, CAIX and CAXII knock-down in combination with ionizing radiation. Fibroblasts cells (-/+ CAIX and LS174Tr cells (inducible knock-down for ca9/ca12 were analyzed for cell cycle phase distribution and survival after irradiation in extracellular pHo manipulations and hypoxia (1% O2 exposure. Radiotherapy was used to target ca9/ca12-silenced LS174Tr tumors grown in nude mice. We found that diminishing the pHi-regulating capacity of fibroblasts through inhibition of NHE-1 sensitize cells to radiation-induced cell death. Secondly, the pHi-regulating function of CAIX plays a key protective role in irradiated fibroblasts in an acidic environment as accompanied by a reduced number of cells in the radiosensitive phases of the cell cycle. Thirdly, we demonstrate that irradiation of LS174Tr spheroids, silenced for either ca9 or both ca9/ca12, showed a respective 50% and 75% increase in cell death as a result of a decrease in cell number in the radioresistant S phase and a disruption of CA-mediated pHi regulation. Finally, LS174Tr tumor progression was strongly decreased when ca9/ca12 silencing was combined with irradiation in vivo. These findings highlight the combinatory use of radiotherapy with targeting of the pHi-regulating carbonic anhydrases as an anti-cancer strategy.

  5. Hypoxia inducible factor-2α regulates the development of retinal astrocytic network by maintaining adequate supply of astrocyte progenitors.

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    Li-Juan Duan

    Full Text Available Here we investigate the role of hypoxia inducible factor (HIF-2α in coordinating the development of retinal astrocytic and vascular networks. Three Cre mouse lines were used to disrupt floxed Hif-2α, including Rosa26(CreERT2, Tie2(Cre, and GFAP(Cre. Global Hif-2α disruption by Rosa26(CreERT2 led to reduced astrocytic and vascular development in neonatal retinas, whereas endothelial disruption by Tie2(Cre had no apparent effects. Hif-2α deletion in astrocyte progenitors by GFAP(Cre significantly interfered with the development of astrocytic networks, which failed to reach the retinal periphery and were incapable of supporting vascular development. Perplexingly, the abundance of strongly GFAP(+ mature astrocytes transiently increased at P0 before they began to lag behind the normal controls by P3. Pax2(+ and PDGFRα(+ astrocytic progenitors and immature astrocytes were dramatically diminished at all stages examined. Despite decreased number of astrocyte progenitors, their proliferation index or apoptosis was not altered. The above data can be reconciled by proposing that HIF-2α is required for maintaining the supply of astrocyte progenitors by slowing down their differentiation into non-proliferative mature astrocytes. HIF-2α deficiency in astrocyte progenitors may accelerate their differentiation into astrocytes, a change which greatly interferes with the replenishment of astrocyte progenitors due to insufficient time for proliferation. Rapidly declining progenitor supply may lead to premature cessation of astrocyte development. Given that HIF-2α protein undergoes oxygen dependent degradation, an interesting possibility is that retinal blood vessels may regulate astrocyte differentiation through their oxygen delivery function. While our findings support the consensus that retinal astrocytic template guides vascular development, they also raise the possibility that astrocytic and vascular networks may mutually regulate each other

  6. CoCl2, a mimic of hypoxia, induces formation of polyploid giant cells with stem characteristics in colon cancer.

    Directory of Open Access Journals (Sweden)

    Laura M Lopez-Sánchez

    Full Text Available The induction of polyploidy is considered the reproductive end of cells, but there is evidence that polyploid giant cancer cells (PGCCs contribute to cell repopulation during tumor relapse. However, the role of these cells in the development, progression and response to therapy in colon cancer remains undefined. Therefore, the main objective of this study was to investigate the generation of PGCCs in colon cancer cells and identify mechanisms of formation. Treatment of HCT-116 and Caco-2 colon cancer cells with the hypoxia mimic CoCl2 induced the formation of cells with larger cell and nuclear size (PGCCs, while the cells with normal morphology were selectively eliminated. Cytometric analysis showed that CoCl2 treatment induced G2 cell cycle arrest and the generation of a polyploid cell subpopulation with increased cellular DNA content. Polyploidy of hypoxia-induced PGCCs was confirmed by FISH analysis. Furthermore, CoCl2 treatment effectively induced the stabilization of HIF-1α, the differential expression of a truncated form of p53 (p47 and decreased levels of cyclin D1, indicating molecular mechanisms associated with cell cycle arrest at G2. Generation of PGCCs also contributed to expansion of a cell subpopulation with cancer stem cells (CSCs characteristics, as indicated by colonosphere formation assays, and enhanced chemoresistance to 5-fluorouracil and oxaliplatin. In conclusion, the pharmacological induction of hypoxia in colon cancer cells causes the formation of PGCCs, the expansion of a cell subpopulation with CSC characteristics and chemoresistance. The molecular mechanisms involved, including the stabilization of HIF-1 α, the involvement of p53/p47 isoform and cell cycle arrest at G2, suggest novel targets to prevent tumor relapse and treatment failure in colon cancer.

  7. Hypoxia-induced down-regulation of neprilysin by histone modification in mouse primary cortical and hippocampal neurons.

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    Zheng Wang

    Full Text Available Amyloid β-peptide (Aβ accumulation leads to neurodegeneration and Alzheimer's disease (AD. Aβ metabolism is a dynamic process in the Aβ production and clearance that requires neprilysin (NEP and other enzymes to degrade Aβ. It has been reported that NEP expression is significantly decreased in the brain of AD patients. Previously we have documented hypoxia is a risk factor for Aβ generation in vivo and in vitro through increasing Aβ generation by altering β-cleavage and γ-cleavage of APP and down-regulating NEP, and causing tau hyperphosphorylation. Here, we investigated the molecular mechanisms of hypoxia-induced down-regulation of NEP. We found a significant decrease in NEP expression at the mRNA and protein levels after hypoxic treatment in mouse primary cortical and hippocampal neurons. Chromatin immunoprecipitation (ChIP assays and relative quantitative PCR (q-PCR revealed an increase of histone H3-lysine9 demethylation (H3K9me2 and a decrease of H3 acetylation (H3-Ace in the NEP promoter regions following hypoxia. In addition, we found that hypoxia caused up-regulation of histone methyl transferase (HMT G9a and histone deacetylases (HDACs HDAC-1. Decreased expression of NEP during hypoxia can be prevented by application with the epigenetic regulators 5-Aza-2'-deoxycytidine (5-Aza, HDACs inhibitor sodium valproate (VA, and siRNA-mediated knockdown of G9a or HDAC1. DNA methylation PCR data do not support that hypoxia affects the methylation of NEP promoters. This study suggests that hypoxia may down-regulate NEP by increasing H3K9me2 and decreasing H3-Ace modulation.

  8. Hypoxia inducible factor-1 improves the negative functional effects of natriuretic peptide and nitric oxide signaling in hypertrophic cardiac myocytes.

    Science.gov (United States)

    Tan, Tao; Scholz, Peter M; Weiss, Harvey R

    2010-07-03

    Both natriuretic peptides and nitric oxide may be protective in cardiac hypertrophy, although their functional effects are diminished in hypertrophy. Hypoxia inducible factor-1 (HIF-1) may also protect in cardiac hypertrophy. We hypothesized that upregulation of HIF-1 would protect the functional effects of cyclic GMP (cGMP) signaling in hypertrophied ventricular myocytes. A cardiac hypertrophy model was created in mice by transverse aorta constriction. HIF-1 was increased by deferoxamine (150 mg/kg for 2 days). HIF-1alpha protein levels were examined. Functional parameters were measured (edge detector) on freshly isolated myocytes at baseline and after BNP (brain natriuretic peptide, 10(-8)-10(-7)M) or CNP (C-type natriuretic peptide, 10(-8)-10(-7)M) or SNAP (S-nitroso-N-acetyl-penicillamine, a nitric oxide donor, 10(-6)-10(-5)M) followed by KT5823 (a cyclic GMP-dependent protein kinase (PKG) inhibitor, 10(-6)M). We also determined PKG expression levels and kinase activity. We found that under control conditions, BNP (-24%), CNP (-22%) and SNAP (-23%) reduced myocyte shortening, while KT5823 partially restored function. Deferoxamine treated control myocytes responded similarly. Baseline function was reduced in the myocytes from hypertrophied heart. BNP, CNP, SNAP and KT5823 also had no significant effects on function in these myocytes. Deferoxamine restored the negative functional effects of BNP (-22%), CNP (-18%) and SNAP (-19%) in hypertrophic cardiac myocytes and KT5823 partially reversed this effect. Additionally, deferoxamine maintained PKG expression levels and activity in hypertrophied heart. Our results indicated that the HIF-1 protected the functional effects of cGMP signaling in cardiac hypertrophy through preservation of PKG. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  9. Hypoxia-Induced Intrauterine Growth Restriction Increases the Susceptibility of Rats to High-Fat Diet–Induced Metabolic Syndrome

    Science.gov (United States)

    Rueda-Clausen, Christian F.; Dolinsky, Vernon W.; Morton, Jude S.; Proctor, Spencer D.; Dyck, Jason R.B.; Davidge, Sandra T.

    2011-01-01

    OBJECTIVE It is recognized that there is a remarkable variability in the systemic response to high-fat (HF) diets that cannot be completely explained by genetic factors. In addition, pregnancy complications leading to intrauterine growth restriction (IUGR) have been associated with an increased risk of developing metabolic syndrome (MetS) later in life. Thus, we hypothesized that offspring born with IUGR exhibit permanent metabolic changes that make them more susceptible to HF diet–induced MetS. RESEARCH DESIGN AND METHODS SD rats born normal (control) or with hypoxia-induced IUGR were randomized to low-fat (10% fat) or HF (45% fat) diets. After 9 weeks of feeding, physiological and molecular pathways involved in the MetS were evaluated. RESULTS IUGR offspring exhibited decreased energy intake and physical activity relative to controls. In offspring fed a HF diet, IUGR was associated with decreased total body fat content, a relative increase in intra-abdominal fat deposition and adipocyte size, an increase in fasting plasma concentrations of leptin, triglyceride and free fatty acids, and an increased concentration of triglycerides and ceramides in both liver and skeletal muscle. These changes in lipid homeostasis were accompanied by in vivo insulin resistance and impaired glucose tolerance and associated with increased phosphorylation of protein kinase C θ, inhibition of insulin receptor substrate 1, and a decreased activation of protein kinase B (PKB; also known as Akt) in liver and skeletal muscle in response to insulin. CONCLUSIONS IUGR enhances specific deleterious metabolic responses to a HF diet. Our results suggest that offspring born with IUGR may require special attention and follow-up to prevent the early onset of MetS. PMID:21270262

  10. Renal expression of hypoxia inducible factor-1α in patients with chronic kidney disease: a clinicopathologic study from nephrectomized kidneys

    Science.gov (United States)

    Tung-Wei, Hung; Jia-Hung, Liou; Kun-Tu, Yeh; Jen-Pi, Tsai; Sheng-Wen, Wu; Hui-Chun, Tai; Wei-Tse, Kao; Shu-Hui, Lin; Ya-Wen, Cheng; Horng-Rong, Chang

    2013-01-01

    Background & objectives: Hypoxia inducible factor-1α (HIF-1α) has been shown to play a role in the pathogenesis of renal interstitial fibrosis. However, the relationship of HIF-1α expression intensity in human renal tissue with the degree of renal function or renal fibrosis has not been investigated. We therefore, undertook this study to assess the relationship between HIF-1α expression and degree of renal impairment and renal fibrosis using renal tissue from nephrectomized kidneys from patients with chronic kidney disease. Methods: This retrospective study was performed with 70 patients undergoing unilateral or bilateral nephrectomy because of renal cell carcinoma, urothelial cell carcinoma, or renal abscess. Immunohistochemical analysis of HIF-1α expression in non-tumourous or non-abscess renal parenchyma was performed. The patients were divided into two groups: group 1 (n=37) with low intensity HIF-1α expression and group 2 (n=33) with high intensity HIF-1α expression. Results: The intensity of renal HIF-1α expression was significantly associated with serum creatinine level (P=0.005), estimated glomerular filtration rate (P=0.02), fibrosis score of the interstitium (P=0.004) and glomerular sclerosis (P=0.013). A high intensity of HIF-1α expression tended to be associated with lower serum creatinine, higher estimated glomerular filtration rate, low interstitial fibrosis score and low glomerular sclerosis. In addition, multivariate analysis by step-wise logistic regression demonstrated that interstitial fibrosis was the only independent factor associated with the intensity of renal HIF-1α expression (OR 4.107, CI 1.535-11.313, P=0.005). Interpretation & conclusions: This study demonstrated a correlation between intensity of HIF-1α expression and degree of renal interstitial fibrosis. The association demonstrated an elevated HIF-1α expression in less severe kidney disease. The intensity of HIF-1α renal expression plays a role in the pathogenesis of

  11. Transarterial embolization combined with RNA interference targeting hypoxia-inducible factor-1α for hepatocellular carcinoma: a preliminary study of rat model.

    Science.gov (United States)

    Ni, Jia-Yan; Xu, Lin-Feng; Wang, Wei-Dong; Huang, Qiao-Sheng; Sun, Hong-Liang; Chen, Yao-Ting

    2017-02-01

    To study whether transarterial embolization (TAE) with RNA interference (RNAi) targeting hypoxia-inducible factor-1α (HIF-1α) can improve efficacy of TAE in treating hepatocellular carcinoma (HCC). CBRH-7919 rat hepatoma cell line was used and HCC models of rats were constructed. The siRNA transfection compound was made by mixing specific siRNA and Lipofectamine 2000™. Delivery and transfection of siRNA were administered by injecting iodized oil emulsion (diluted lipiodol and siRNA) via hepatic artery. The expression levels of mRNA and protein were detected using the real-time reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry and western blotting assays, respectively. In vitro experiment, the specific HIF-1α-siRNA was proved to inhibit expression levels of HIF-1α and vascular endothelial growth factor (VEGF) effectively. In animal study, real-time RT-PCR assay showed the average relative mRNA expressions of HIF-1α were 0.31 ± 0.01, 0.65 ± 0.03, 0.46 ± 0.005, and 1.00 ± 0.00 in TAE + siRNA, siRNA, TAE, and control groups, respectively. Western blotting assay showed the average relative protein expressions of HIF-1α were 0.13 ± 0.02, 0.87 ± 0.02, 0.39 ± 0.02, and 1.02 ± 0.01 in TAE + siRNA, siRNA, TAE, and control groups, respectively. Compared with control, TAE, and siRNA groups, TAE + siRNA can significantly inhibit protein expressions of HIF-1α and VEGF (P HIF-1α < 0.001; P VEGF < 0.001). Overall survival of rats underwent TAE + siRNA was significantly longer than that of rats treated with TAE monotherapy (P = 0.001). This animal study showed TAE combined with HIF-1α-RNAi could significantly improve efficacy of TAE in treating HCC by inhibiting expressions of HIF-1α and VEGF after TAE treatment.

  12. In Vivo Hypoxia PET Imaging Quantifies the Severity of Arthritic Joint Inflammation in Line with Overexpression of Hypoxia-Inducible Factor and Enhanced Reactive Oxygen Species Generation.

    Science.gov (United States)

    Fuchs, Kerstin; Kuehn, Anna; Mahling, Moritz; Guenthoer, Philipp; Hector, Andreas; Schwenck, Johannes; Hartl, Dominik; Laufer, Stefan; Kohlhofer, Ursula; Quintanilla-Martinez, Leticia; Reischl, Gerald; Röcken, Martin; Pichler, Bernd J; Kneilling, Manfred

    2017-05-01

    Hypoxia is essential for the development of autoimmune diseases such as rheumatoid arthritis (RA) and is associated with the expression of reactive oxygen species (ROS), because of the enhanced infiltration of immune cells. The aim of this study was to demonstrate the feasibility of measuring hypoxia noninvasively in vivo in arthritic ankles with PET/MRI using the hypoxia tracers 18F-fluoromisonidazole (18F-FMISO) and 18F-fluoroazomycinarabinoside (18F-FAZA). Additionally, we quantified the temporal dynamics of hypoxia and ROS stress using L-012, an ROS-sensitive chemiluminescence optical imaging probe, and analyzed the expression of hypoxia-inducible factors (HIFs). Methods: Mice underwent noninvasive in vivo PET/MRI to measure hypoxia or optical imaging to analyze ROS expression. Additionally, we performed ex vivo pimonidazole-/HIF-1α immunohistochemistry and HIF-1α/2α Western blot/messenger RNA analysis of inflamed and healthy ankles to confirm our in vivo results. Results: Mice diseased from experimental RA exhibited a 3-fold enhancement in hypoxia tracer uptake, even in the early disease stages, and a 45-fold elevation in ROS expression in inflamed ankles compared with the ankles of healthy controls. We further found strong correlations of our noninvasive in vivo hypoxia PET data with pimonidazole and expression of HIF-1α in arthritic ankles. The strongest hypoxia tracer uptake was observed as soon as day 3, whereas the most pronounced ROS stress was evident on day 6 after the onset of experimental RA, indicating that tissue hypoxia can precede ROS stress in RA. Conclusion: Collectively, for the first time to our knowledge, we have demonstrated that the noninvasive measurement of hypoxia in inflammation using 18F-FAZA and 18F-FMISO PET imaging represents a promising new tool for uncovering and monitoring rheumatic inflammation in vivo. Further, because hypoxic inflamed tissues are associated with the overexpression of HIFs, specific inhibition of HIFs

  13. The anti-proliferative effect of L-carnosine correlates with a decreased expression of hypoxia inducible factor 1 alpha in human colon cancer cells.

    Directory of Open Access Journals (Sweden)

    Barbara Iovine

    Full Text Available In recent years considerable attention has been given to the use of natural substances as anticancer drugs. The natural antioxidant dipeptide L-carnosine belongs to this class of molecules because it has been proved to have a significant anticancer activity both in vitro and in vivo. Previous studies have shown that L-carnosine inhibits the proliferation of human colorectal carcinoma cells by affecting the ATP and Reactive Oxygen Species (ROS production. In the present study we identified the Hypoxia-Inducible Factor 1α (HIF-1α as a possible target of L-carnosine in HCT-116 cell line. HIF-1α protein is over-expressed in multiple types of human cancer and is the major cause of resistance to drugs and radiation in solid tumours. Of particular interest are experimental data supporting the concept that generation of ROS provides a redox signal for HIF-1α induction, and it is known that some antioxidants are able to suppress tumorigenesis by inhibiting HIF-1α. In the current study we found that L-carnosine reduces the HIF-1α protein level affecting its stability and decreases the HIF-1 transcriptional activity. In addition, we demonstrated that L-carnosine is involved in ubiquitin-proteasome system promoting HIF-1α degradation. Finally, we compared the antioxidant activity of L-carnosine with that of two synthetic anti-oxidant bis-diaminotriazoles (namely 1 and 2, respectively. Despite these three compounds have the same ability in reducing intracellular ROS, 1 and 2 are more potent scavengers and have no effect on HIF-1α expression and cancer cell proliferation. These findings suggest that an analysis of L-carnosine antioxidant pathway will clarify the mechanism underlying the anti-proliferative effects of this dipeptide on colon cancer cells. However, although the molecular mechanism by which L-carnosine down regulates or inhibits the HIF-1α activity has not been yet elucidated, this ability may be promising in treating hypoxia

  14. Selective class I histone deacetylase inhibition suppresses hypoxia-induced cardiopulmonary remodeling through an antiproliferative mechanism.

    Science.gov (United States)

    Cavasin, Maria A; Demos-Davies, Kim; Horn, Todd R; Walker, Lori A; Lemon, Douglas D; Birdsey, Nicholas; Weiser-Evans, Mary C M; Harral, Julie; Irwin, David C; Anwar, Adil; Yeager, Michael E; Li, Min; Watson, Peter A; Nemenoff, Raphael A; Buttrick, Peter M; Stenmark, Kurt R; McKinsey, Timothy A

    2012-03-02

    Histone deacetylase (HDAC) inhibitors are efficacious in models of hypertension-induced left ventricular heart failure. The consequences of HDAC inhibition in the context of pulmonary hypertension with associated right ventricular cardiac remodeling are poorly understood. This study was performed to assess the utility of selective small-molecule inhibitors of class I HDACs in a preclinical model of pulmonary hypertension. Rats were exposed to hypobaric hypoxia for 3 weeks in the absence or presence of a benzamide HDAC inhibitor, MGCD0103, which selectively inhibits class I HDACs 1, 2, and 3. The compound reduced pulmonary arterial pressure more dramatically than tadalafil, a standard-of-care therapy for human pulmonary hypertension that functions as a vasodilator. MGCD0103 improved pulmonary artery acceleration time and reduced systolic notching of the pulmonary artery flow envelope, which suggests a positive impact of the HDAC inhibitor on pulmonary vascular remodeling and stiffening. Similar results were obtained with an independent class I HDAC-selective inhibitor, MS-275. Reduced pulmonary arterial pressure in MGCD0103-treated animals was associated with blunted pulmonary arterial wall thickening because of suppression of smooth muscle cell proliferation. Right ventricular function was maintained in MGCD0103-treated animals. Although the class I HDAC inhibitor only modestly reduced right ventricular hypertrophy, it had multiple beneficial effects on the right ventricle, which included suppression of pathological gene expression, inhibition of proapoptotic caspase activity, and repression of proinflammatory protein expression. By targeting distinct pathogenic mechanisms, isoform-selective HDAC inhibitors have potential as novel therapeutics for pulmonary hypertension that will complement vasodilator standards of care.

  15. Improving heterologous protein secretion at aerobic conditions by activating hypoxia-induced genes in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Liu, Lifang; Zhang, Yiming; Liu, Zihe

    2015-01-01

    cerevisiae. Intriguingly, we found a 100% increase in the recombinant fungal α-amylase yield, as well as productivity. Varied levels of improvements were also observed for the productions of the human insulin precursor and the yeast endogenous enzyme invertase. Based on the genome-wide transcriptional...

  16. EMF protects cardiomyocytes against hypoxia-induced injury via heat shock protein 70 activation.

    Science.gov (United States)

    Wei, Jinhong; Tong, Jie; Yu, Liying; Zhang, Jianbao

    2016-03-25

    Intracellular calcium (Ca(2+)i) overload induced by chronic hypoxia alters Ca(2+)i homeostasis, whereas ameliorating calcium homeostasis is believed to be responsible for cardioprotection. We hypothesize that cardioprotection by electromagnetic fields (EMF) exposure may restore Ca(2+)i homeostasis altered by hypoxia insults. Cardiomyocytes isolated from neonatal Sprague-Dawley rats were exposed to chronic hypoxia (1% O2, 5% CO2, 37 °C). We observed that cardiomyocytes injury and hypertrophy were alleviated in hypoxic cardiomyocytes exposed with EMF preconditioning. Compared with hypoxic cardiomyocytes, the diastolic [Ca(2+)]i was decreased, the amplitude of Ca(2+)i oscillations was recovered when cardiomyocytes exposed with EMF. In addition, we also found that EMF exposure significantly increased heat shock protein 70 (HSP70) mRNA expression in hypoxic cardiomyocytes. However, treatment with HSP70 blocker KNK437, almost completely inhibited the EMF induced-cardioprotection and the beneficial effects of Ca(2+) oscillation in hypoxic cardiomyocytes. These results suggest that EMF preconditioning ameliorates Ca(2+)i homeostasis through activating HSP70, thereby producing the cardioprotective effect and reduction in hypoxic cardiomyocytes damage. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Complement C3 deficiency attenuates chronic hypoxia-induced pulmonary hypertension in mice.

    Directory of Open Access Journals (Sweden)

    Eileen M Bauer

    Full Text Available Evidence suggests a role of both innate and adaptive immunity in the development of pulmonary arterial hypertension. The complement system is a key sentry of the innate immune system and bridges innate and adaptive immunity. To date there are no studies addressing a role for the complement system in pulmonary arterial hypertension.Immunofluorescent staining revealed significant C3d deposition in lung sections from IPAH patients and C57Bl6/J wild-type mice exposed to three weeks of chronic hypoxia to induce pulmonary hypertension. Right ventricular systolic pressure and right ventricular hypertrophy were increased in hypoxic vs. normoxic wild-type mice, which were attenuated in C3-/- hypoxic mice. Likewise, pulmonary vascular remodeling was attenuated in the C3-/- mice compared to wild-type mice as determined by the number of muscularized peripheral arterioles and morphometric analysis of vessel wall thickness. The loss of C3 attenuated the increase in interleukin-6 and intracellular adhesion molecule-1 expression in response to chronic hypoxia, but not endothelin-1 levels. In wild-type mice, but not C3-/- mice, chronic hypoxia led to platelet activation as assessed by bleeding time, and flow cytometry of platelets to determine cell surface P-selectin expression. In addition, tissue factor expression and fibrin deposition were increased in the lungs of WT mice in response to chronic hypoxia. These pro-thrombotic effects of hypoxia were abrogated in C3-/- mice.Herein, we provide compelling genetic evidence that the complement system plays a pathophysiologic role in the development of PAH in mice, promoting pulmonary vascular remodeling and a pro-thrombotic phenotype. In addition we demonstrate C3d deposition in IPAH patients suggesting that complement activation plays a role in the development of PAH in humans.

  18. Celecoxib Down-Regulates the Hypoxia-Induced Expression of HIF-1α and VEGF Through the PI3K/AKT Pathway in Retinal Pigment Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Yi-zhou Sun

    2017-12-01

    Full Text Available Background/Aims: The goal of this study was to detect the expression of hypoxia-inducible factor 1α (HIF-1α and vascular endothelial growth factor (VEGF in human retinal pigmented epithelial (RPE cells treated with celecoxib, a selective cyclooxygenase-2 (COX-2 inhibitor, under hypoxic and normoxic conditions and to explore the signaling mechanism involved in regulating the hypoxia-induced expression of HIF-1α and VEGF in RPE cells. Methods: D407 cells were cultured in normoxic or hypoxic conditions, with or without celecoxib or a PI3K inhibitor (LY294002. The anti-proliferative effect of celecoxib was assessed using the MTT assay. RT-PCR, Western blotting and ELISA were performed to detect the levels of PI3K, phosphorylated AKT (p-AKT, HIF-1α, VEGF and COX-2. Results: Celecoxib inhibited the proliferation of RPE cells in a dose-dependent manner. Celecoxib suppressed the expression of VEGF at both the mRNA and protein levels and decreased HIF-1α protein expression. HIF-1α activation was regulated by the PI3K/AKT pathway. The celecoxib-induced down-regulation of HIF-1α and VEGF required the suppression of the hypoxia-induced PI3K/AKT pathway. However, the down-regulation of COX-2 did not occur in cells treated with celecoxib. Conclusions: The antiangiogenic effects of celecoxib in RPE cells under hypoxic conditions resulted from the inhibition of HIF-1α and VEGF expression, which may be partly mediated by a COX-2-independent, PI3K/AKT-dependent pathway.

  19. Involvement of Ca2+-activated K+channel 3.1 in hypoxia-induced pulmonary arterial hypertension and therapeutic effects of TRAM-34 in rats.

    Science.gov (United States)

    Guo, Shujin; Shen, Yongchun; He, Guangming; Wang, Tao; Xu, Dan; Wen, Fuqiang

    2017-08-31

    Pulmonary artery hypertension (PAH) is an incurable disease associated with the proliferation of pulmonary artery smooth muscle cells (PASMCs) and vascular remodeling. The present study examined whether TRAM-34, a highly selective blocker of calcium-activated potassium channel 3.1 (Kca3.1), can help prevent such hypertension by reducing proliferation in PASMCs. Rats were exposed to hypoxia (10% O 2 ) for 3 weeks and treated daily with TRAM-34 intraperitoneally from the first day of hypoxia. Animals were killed and examined for vascular hypertrophy, Kca3.1 expression, and downstream signaling pathways. In addition, primary cultures of rat PASMCs were exposed to hypoxia (3% O 2 ) or normoxia (21% O 2 ) for 24 h in the presence of TRAM-34 or siRNA against Kca3.1. Activation of cell signaling pathways was examined using Western blot analysis. In animal experiments, hypoxia triggered significant medial hypertrophy of pulmonary arterioles and right ventricular hypertrophy, and it significantly increased pulmonary artery pressure, Kca3.1 mRNA levels and ERK/p38 MAP kinase signaling. These effects were attenuated in the presence of TRAM-34. In cell culture experiments, blocking Kca3.1 using TRAM-34 or siRNA inhibited hypoxia-induced ERK/p38 signaling. Kca3.1 may play a role in the development of PAH by activating ERK/p38 MAP kinase signaling, which may then contribute to hypoxia-induced pulmonary vascular remodeling. TRAM-34 may protect against hypoxia-induced PAH. © 2017 The Author(s).

  20. Minocycline ameliorates hypoxia-induced blood-brain barrier damage by inhibition of HIF-1α through SIRT-3/PHD-2 degradation pathway.

    Science.gov (United States)

    Yang, F; Zhou, L; Wang, D; Wang, Z; Huang, Q-Y

    2015-09-24

    Minocycline, a second-generation tetracycline alleviates neuro-inflammation and protects the blood-brain barrier (BBB) in ischemia stroke. However, the effect of minocycline in hypoxia-induced BBB damage is unclear. Here, we have investigated the effect of minocycline under hypoxia and explored its possible underlying mechanisms. The effect of minocycline was examined in vitro in Human Brain Microvascular Endothelial Cells (HBMECs) using Trans Epithelial Electric Resistance (TEER). Protein and mRNA expression of Hypoxia-Inducible Factors-1α (HIF-1α), matrix metalloproteinases (MMP-2 and MMP-9) and tight junction proteins (TJs) were detected by using Western blot and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The translocation and transcription of HIF-1α were detected by using immunocytochemistry and luciferase reporter assay. In vivo, to adult male Sprague Dawley (SD) rats under hypobaric hypoxia were administered minocycline for 1h and BBB permeability was tested by using Evans Blue and Transmission Electron Microscopy (TEM). Also, reduction of NAD-dependent deacetylase sirtuin-3 (SIRT-3)/proline hydroxylase-2 (PHD-2) signaling pathway was evaluated. Minocycline increased TEER in HBMECs after hypoxia (PMinocycline administration significantly reduced HIF-1α expression, protein and mRNA expression of MMP-2, MMP-9 and Vascular Endothelial Growth Factor (VEGF) (Pminocycline reversed the hypoxia-induced reduction of PHD-2 (Pminocycline were abolished by siRNA-mediated knockdown of SIRT-3 in the brain. Minocycline inhibits HIF-1α-mediated cellular responses and protects BBB integrity through SIRT-3/PHD-2 pathway, proving to be a potential drug for the prevention and treatment of hypoxic brain injuries. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  1. Decay accelerating factor (CD55 protects neuronal cells from chemical hypoxia-induced injury

    Directory of Open Access Journals (Sweden)

    Tsokos George C

    2010-04-01

    Full Text Available Abstract Background Activated complement system is known to mediate neuroinflammation and neurodegeneration following exposure to hypoxic-ischemic insults. Therefore, inhibition of the complement activation cascade may represent a potential therapeutic strategy for the management of ischemic brain injury. Decay-accelerating factor (DAF, also known as CD55 inhibits complement activation by suppressing the function of C3/C5 convertases, thereby limiting local generation or deposition of C3a/C5a and membrane attack complex (MAC or C5b-9 production. The present study investigates the ability of DAF to protect primary cultured neuronal cells subjected to sodium cyanide (NaCN-induced hypoxia from degeneration and apoptosis. Methods Cultured primary cortical neurons from embryonic Sprague-Dawley rats were assigned one of four groups: control, DAF treatment alone, hypoxic, or hypoxic treated with DAF. Hypoxic cultures were exposed to NaCN for 1 hour, rinsed, followed by 24 hour exposure to 200 ng/ml of recombinant human DAF in normal medium. Human DAF was used in the present study and it has been shown to effectively regulate complement activation in rats. Neuronal cell function, morphology and viability were investigated by measuring plateau depolarization potential, counting the number dendritic spines, and observing TUNEL and MTT assays. Complement C3, C3a, C3a receptor (R production, C3a-C3aR interaction and MAC formation were assessed along with the generation of activated caspase-9, activated caspase-3, and activated Src. Results When compared to controls, hypoxic cells had fewer dendritic spines, reduced plateau depolarization accompanied by increased apoptotic activity and accumulation of MAC, as well as up-regulation of C3, C3a and C3aR, enhancement of C3a-C3aR engagement, and elevated caspase and Src activity. Treatment of hypoxic cells with 200 ng/ml of recombinant human DAF resulted in attenuation of neuronal apoptosis and exerted

  2. A comparative study of mutation screening of sarcomeric genes ...

    African Journals Online (AJOL)

    However there have been limited direct comparisons between NGS and more established technologies to assess the sensitivity and false negative rates of this new approach. The scope of the present manuscript is to compare variants detected in MYBPC3, MYH7 and TNNT2 genes using the stepwise dHPLC/ Sanger ...

  3. Early expressions of hypoxia-inducible factor 1alpha and vascular endothelial growth factor increase the neuronal plasticity of activated endogenous neural stem cells after focal cerebral ischemia.

    Science.gov (United States)

    Song, Seung; Park, Jong-Tae; Na, Joo Young; Park, Man-Seok; Lee, Jeong-Kil; Lee, Min-Cheol; Kim, Hyung-Seok

    2014-05-01

    Endogenous neural stem cells become "activated" after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2'-deoxyuridine (BrdU) incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3-7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular

  4. Antioxidant potential, total phenolic and total flavonoid contents of Rhododendron anthopogonoides and its protective effect on hypoxia-induced injury in PC12 cells.

    Science.gov (United States)

    Jing, Linlin; Ma, Huiping; Fan, Pengcheng; Gao, Rongmin; Jia, Zhengping

    2015-08-18

    Rhododendron anthopogonoides Maxim, a kind of traditional Tibetan medicine, has been used to remove body heat, body detoxification, cough, asthma, stomachic and swelling, eliminate abundant phlegm and inflammatory for a long time. In the present study, the total phenols and total flavonoid contents as well as antioxidative properties of the crude extract and solvent fractions of R. anthopogonoides were determined using seven antioxidant assays. Additionally, the protective effect of the extracts on hypoxia-induced injury in PC12 cells was also investigated. The content of total flavonoid and total phenolic was determined by the aluminum colorimetric method and Folin-Ciocalteu assay, respectively. In vitro antioxidant study, the effect of the crude extract and solvent fractions on total antioxidant activity, reducing power, DPPH radical scavenging, ABTS radical scavenging, superoxide radical scavenging, hydroxyl radical scavenging and nitric oxide radical scavenging were examined. The correlation between the phenolic and flavonoid content of the extracts and their antioxidant properties also analyzed. Furthermore, the protective effect of extracts on hypoxia-induced damage on PC12 cells was investigated by cell viability, lactate dehydrogenase (LDH) release, malondialdehyde (MDA) production and the activities of antioxidant enzymes. Our results showed that ethyl acetate and n-butanol fractions had higher content of phenolics and flavonoid compounds than other fractions. Except ABTS radical assay, n-butanol fraction exhibited the strongest antioxidant activity. While the hexane fraction showed the lowest antioxidant activity. Ethyl acetate also presented excellent antioxidant activity, which was just lower than n-butanol fraction. Significant correlation between the phenolic, flavonoid content of the extract and fractions with antioxidant assay excluding ABTS, OH scavenging assay was observed. Moreover, ethyl acetate and n-butanol fractions showed protective effect

  5. Expressions of endoplasmic reticulum stress related protein, hypoxia-inducible factor-1α and vascular endothelial growth factor in the retina of diabetic rats

    OpenAIRE

    Jing Wang; Hong Zhu; Cai-Hong Shi

    2015-01-01

    AIM: To evaluate the expressions and significances of endoplasmic reticulum stress related protein(BIP), hypoxia-inducible factor-1α(HIF-1α)and vascular endothelial growth factor(VEGF)in the retina of diabetic rats.METHODS: Seventy-two male Sprague-Dawley(SD)rats were chosen and divided randomly into 6 groups: normal control 2mo(C2m, n=12), diabetes mellitus 2mo(D2m, n=12), normal control 4mo(C4m, n=12), diabetes mellitus 4mo(D4m, n=12), normal control 6mo(C6m, n=12)and diabetes mellitus 6mo(...

  6. The mRNA-binding protein HuR promotes hypoxia-induced chemoresistance through posttranscriptional regulation of the proto-oncogene PIM1 in pancreatic cancer cells.

    Science.gov (United States)

    Blanco, F F; Jimbo, M; Wulfkuhle, J; Gallagher, I; Deng, J; Enyenihi, L; Meisner-Kober, N; Londin, E; Rigoutsos, I; Sawicki, J A; Risbud, M V; Witkiewicz, A K; McCue, P A; Jiang, W; Rui, H; Yeo, C J; Petricoin, E; Winter, J M; Brody, J R

    2016-05-01

    Previously, it has been shown that pancreatic ductal adenocarcinoma (PDA) tumors exhibit high levels of hypoxia, characterized by low oxygen pressure (pO2) and decreased O2 intracellular perfusion. Chronic hypoxia is strongly associated with resistance to cytotoxic chemotherapy and chemoradiation in an understudied phenomenon known as hypoxia-induced chemoresistance. The hypoxia-inducible, pro-oncogenic, serine-threonine kinase PIM1 (Proviral Integration site for Moloney murine leukemia virus 1) has emerged as a key regulator of hypoxia-induced chemoresistance in PDA and other cancers. Although its role in therapeutic resistance has been described previously, the molecular mechanism behind PIM1 overexpression in PDA is unknown. Here, we demonstrate that cis-acting AU-rich elements (ARE) present within a 38-base pair region of the PIM1 mRNA 3'-untranslated region mediate a regulatory interaction with the mRNA stability factor HuR (Hu antigen R) in the context of tumor hypoxia. Predominantly expressed in the nucleus in PDA cells, HuR translocates to the cytoplasm in response to hypoxic stress and stabilizes the PIM1 mRNA transcript, resulting in PIM1 protein overexpression. A reverse-phase protein array revealed that HuR-mediated regulation of PIM1 protects cells from hypoxic stress through phosphorylation and inactivation of the apoptotic effector BAD and activation of MEK1/2. Importantly, pharmacological inhibition of HuR by MS-444 inhibits HuR homodimerization and its cytoplasmic translocation, abrogates hypoxia-induced PIM1 overexpression and markedly enhances PDA cell sensitivity to oxaliplatin and 5-fluorouracil under physiologic low oxygen conditions. Taken together, these results support the notion that HuR has prosurvival properties in PDA cells by enabling them with growth advantages in stressful tumor microenvironment niches. Accordingly, these studies provide evidence that therapeutic disruption of HuR's regulation of PIM1 may be a key strategy in

  7. Reciprocal relationship between expression of hypoxia inducible factor 1alpha (HIF-1alpha) and the pro-apoptotic protein bid in ex vivo colorectal cancer.

    Science.gov (United States)

    Seenath, M M; Roberts, D; Cawthorne, C; Saunders, M P; Armstrong, G R; O'Dwyer, S T; Stratford, I J; Dive, C; Renehan, A G

    2008-08-05

    Hypoxia inducible factor 1 (HIF-1) represses the transcription of pro-apoptotic bid in colorectal cancer cells in vitro. To assess the clinical relevance of this observation, HIF-1alpha and Bid were assessed in serial sections of 39 human colorectal adenocarcinomas by immunohistochemistry. In high HIF-1alpha nuclear-positive cell subpopulations, there was a significant reduction in Bid expression (ANOVA, P=0.04). Given the role of Bid in drug-induced apoptosis, these data add impetus to strategies targeting HIF-1 for therapeutic gain.

  8. The clinical impact of hypoxia-regulated gene expression in loco-regional gastroesophageal cancer

    DEFF Research Database (Denmark)

    Winther, M.; Alsner, J.; Tramm, T.

    2015-01-01

    patients with GC treated with neoadjuvant or definitive chemoradiotherapy or perioperative chemotherapy. Based on formalin-fixed, paraffin-embedded, diagnostic biopsies, gene expression of the 15 hypoxia-induced and pH-independent genes was obtained with qPCR. Sufficient amounts of RNA for gene analyses...

  9. In Vivo Imaging Reveals Significant Tumor Vascular Dysfunction and Increased Tumor Hypoxia-Inducible Factor-1α Expression Induced by High Single-Dose Irradiation in a Pancreatic Tumor Model

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Azusa [Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Chen, Yonghong; Bu, Jiachuan; Mujcic, Hilda [Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Wouters, Bradly G. [Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); DaCosta, Ralph S., E-mail: rdacosta@uhnres.utoronto.ca [Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Techna Institute, University Health Network, Toronto, Ontario (Canada)

    2017-01-01

    Purpose: To investigate the effect of high-dose irradiation on pancreatic tumor vasculature and microenvironment using in vivo imaging techniques. Methods and Materials: A BxPC3 pancreatic tumor xenograft was established in a dorsal skinfold window chamber model and a subcutaneous hind leg model. Tumors were irradiated with a single dose of 4, 12, or 24 Gy. The dorsal skinfold window chamber model was used to assess tumor response, vascular function and permeability, platelet and leukocyte adhesion to the vascular endothelium, and tumor hypoxia for up to 14 days after 24-Gy irradiation. The hind leg model was used to monitor tumor size, hypoxia, and vascularity for up to 65 days after 24-Gy irradiation. Tumors were assessed histologically to validate in vivo observations. Results: In vivo fluorescence imaging revealed temporary vascular dysfunction in tumors irradiated with a single dose of 4 to 24 Gy, but most significantly with a single dose of 24 Gy. Vascular functional recovery was observed by 14 days after irradiation in a dose-dependent manner. Furthermore, irradiation with 24 Gy caused platelet and leukocyte adhesion to the vascular endothelium within hours to days after irradiation. Vascular permeability was significantly higher in irradiated tumors compared with nonirradiated controls 14 days after irradiation. This observation corresponded with increased expression of hypoxia-inducible factor-1α in irradiated tumors. In the hind leg model, irradiation with a single dose of 24 Gy led to tumor growth delay, followed by tumor regrowth. Conclusions: Irradiation of the BxPC3 tumors with a single dose of 24 Gy caused transient vascular dysfunction and increased expression of hypoxia-inducible factor-1α. Such biological changes may impact tumor response to high single-dose and hypofractionated irradiation, and further investigations are needed to better understand the clinical outcomes of stereotactic body radiation therapy.

  10. Hepatocyte Hypoxia Inducible Factor-1 Mediates the Development of Liver Fibrosis in a Mouse Model of Nonalcoholic Fatty Liver Disease.

    Directory of Open Access Journals (Sweden)

    Omar A Mesarwi

    Full Text Available Obstructive sleep apnea (OSA is associated with the progression of non-alcoholic fatty liver disease (NAFLD to steatohepatitis and fibrosis. This progression correlates with the severity of OSA-associated hypoxia. In mice with diet induced obesity, hepatic steatosis leads to liver tissue hypoxia, which worsens with exposure to intermittent hypoxia. Emerging data has implicated hepatocyte cell signaling as an important factor in hepatic fibrogenesis. We hypothesized that hepatocyte specific knockout of the oxygen sensing α subunit of hypoxia inducible factor-1 (HIF-1, a master regulator of the global response to hypoxia, may be protective against the development of liver fibrosis.Wild-type mice and mice with hepatocyte-specific HIF-1α knockout (Hif1a-/-hep were fed a high trans-fat diet for six months, as a model of NAFLD. Hepatic fibrosis was evaluated by Sirius red stain and hydroxyproline assay. Liver enzymes, fasting insulin, and hepatic triglyceride content were also assessed. Hepatocytes were isolated from Hif1a-/-hep mice and wild-type controls and were exposed to sustained hypoxia (1% O2 or normoxia (16% O2 for 24 hours. The culture media was used to reconstitute type I collagen and the resulting matrices were examined for collagen cross-linking.Wild-type mice on a high trans-fat diet had 80% more hepatic collagen than Hif1a-/-hep mice (2.21 μg collagen/mg liver tissue, versus 1.23 μg collagen/mg liver tissue, p = 0.03, which was confirmed by Sirius red staining. Body weight, liver weight, mean hepatic triglyceride content, and fasting insulin were similar between groups. Culture media from wild-type mouse hepatocytes exposed to hypoxia allowed for avid collagen cross-linking, but very little cross-linking was seen when hepatocytes were exposed to normoxia, or when hepatocytes from Hif1a-/-hep mice were used in hypoxia or normoxia.Hepatocyte HIF-1 mediates an increase in liver fibrosis in a mouse model of NAFLD, perhaps due to liver

  11. Sumoylation of hypoxia-inducible factor-1α ameliorates failure of brain stem cardiovascular regulation in experimental brain death.

    Directory of Open Access Journals (Sweden)

    Julie Y H Chan

    2011-03-01

    Full Text Available One aspect of brain death is cardiovascular deregulation because asystole invariably occurs shortly after its diagnosis. A suitable neural substrate for mechanistic delineation of this aspect of brain death resides in the rostral ventrolateral medulla (RVLM. RVLM is the origin of a life-and-death signal that our laboratory detected from blood pressure of comatose patients that disappears before brain death ensues. At the same time, transcriptional upregulation of heme oxygenase-1 in RVLM by hypoxia-inducible factor-1α (HIF-1α plays a pro-life role in experimental brain death, and HIF-1α is subject to sumoylation activated by transient cerebral ischemia. It follows that sumoylation of HIF-1α in RVLM in response to hypoxia may play a modulatory role on brain stem cardiovascular regulation during experimental brain death.A clinically relevant animal model that employed mevinphos as the experimental insult in Sprague-Dawley rat was used. Biochemical changes in RVLM during distinct phenotypes in systemic arterial pressure spectrum that reflect maintained or defunct brain stem cardiovascular regulation were studied. Western blot analysis, EMSA, ELISA, confocal microscopy and immunoprecipitation demonstrated that drastic tissue hypoxia, elevated levels of proteins conjugated by small ubiquitin-related modifier-1 (SUMO-1, Ubc9 (the only known conjugating enzyme for the sumoylation pathway or HIF-1α, augmented sumoylation of HIF-1α, nucleus-bound translocation and enhanced transcriptional activity of HIF-1α in RVLM neurons took place preferentially during the pro-life phase of experimental brain death. Furthermore, loss-of-function manipulations by immunoneutralization of SUMO-1, Ubc9 or HIF-1α in RVLM blunted the upregulated nitric oxide synthase I/protein kinase G signaling cascade, which sustains the brain stem cardiovascular regulatory machinery during the pro-life phase.We conclude that sumoylation of HIF-1α in RVLM ameliorates brain stem

  12. Imaging of hypoxia-inducible factor 1α and septin 9 interaction by bimolecular fluorescence complementation in live cancer cells.

    Science.gov (United States)

    Golan, Maya; Mabjeesh, Nicola J

    2017-05-09

    Hypoxia-inducible factor 1 (HIF-1) is a major mediator of the hypoxic response involved in tumor progression. We had earlier described the interaction between septin 9 isoform 1 (SEPT9_i1) protein and the oxygen-regulated subunit, HIF-1α. SEPT9_i1 is a member of the conserved family of GTP-binding cytoskeleton septins. SEPT9_i1 stabilizes HIF-1α and facilitates its cytoplasmic-nuclear translocation. We utilized split yellow fluorescent protein (YFP) bimolecular fluorescence complementation (BiFC) methodology to monitor the interaction between HIF-1α and SEPT9_i1 in live cells. N-terminal (YN) and C-terminal (YC) split YFP chimeras with HIF-1α and SEPT9_i1 on both their amino and carboxyl termini were generated. HIF-1α and SEPT9_i1 chimeras were expressed in cancer cells and screened for functional complementation. SEPT9_i1-YN and YC-HIF-1α formed a long-lived highly stable complex upon interaction. The BiFC signal was increased in the presence of hypoxia-mimicking agents. In contrast, YC-ΔHLH-HIF-1α chimera, which lacked the helix-loop-helix domain that is essential for the interaction with SEPT9_i1 as well as the expression of SEPT9_i1 252-379 amino acids fragment required for the interaction with HIF-1α, significantly reduced the BiFC signal. The signal was also reduced when cells were treated with 17-N-allylamino-17-demethoxygeldanamycin, an HSP90 inhibitor that inhibits HIF-1α. It was increased with fourchlorfenuron, a small molecule that increases the interaction between HIF-1α and SEPT9_i1. These results reconfirmed the interaction between HIF-1α and SEPT9_i1 that was imaged in live cells. This BiFC system represents a novel approach for studying the real-time interaction between these two proteins and will allow high-throughput drug screening to identity compounds that disrupt this interaction.

  13. El factor inducible por la hipoxia y la actividad física hypoxia-inducible factor and physical activity

    Directory of Open Access Journals (Sweden)

    Juan Camilo Calderón Vélez

    2007-04-01

    Full Text Available Los animales superiores dependen de un adecuado flujo de oxígeno. Los mecanismos involucrados en los procesos de percibir la hipoxia y responder a ella se han ido aclarando, desde hace unos 15 años, con el descubrimiento de las subunidades α y β del factor inducible por la hipoxia (HIF, por su sigla en inglés y de las hidroxilasas involucradas en su regulación. Las especies reactivas de oxígeno (ERO, al parecer, también participan en el proceso de percibir y responder a la hipoxia. Las células musculares podrían ser un modelo útil para estudiar la interrelación hipoxia-ERO-HIF- respuesta celular, con importantes implicaciones básico-clínicas. Sin embargo, apenas comienza el estudio de esta relación en el músculo esquelético. Se revisan en este artículo algunos aspectos interesantes de la investigación en el músculo esquelético y se plantean algunas preguntas e hipótesis que podrían ser evaluadas en este tipo de células. Higher animals depend on an adequate oxygen flux. Mechanisms involved in the process of sensing and responding to hypoxia have become clearer in the last 15 years with the discovery of the y hypoxia-inducible factor (HIF subunits and hydroxylases involved in their regulation. Reactive oxygen species seem to play some role in the process of sensing and responding to hypoxia. Skeletal muscle cells seem to be a suitable model for studying the hypoxia-reactive oxygen species-HIF-cellular response relationship. Its study has important basic and clinic implications. However, the study of this relationship just begins. Some interesting aspects regarding skeletal muscle research are reviewed in this article, and some questions and hypotheses suitable for being evaluated with muscle cells are discussed.

  14. Hypoxia-inducible factor-1α polymorphisms and TSC1/2 mutations are complementary in head and neck cancers

    Directory of Open Access Journals (Sweden)

    Nikitakis Nikolaos G

    2006-01-01

    Full Text Available Abstract Background Polymorphisms or mutations in hypoxia inducible factor-1 alpha (HIF-1alpha that increases its activity and stability under normoxia have recently been identified. Likewise, disruption of the TSC1/TSC2 complex through loss of TSC1 or TSC2 has been shown to result in abnormal accumulation of HIF-1α. Here, we investigate the novel polymorphisms in exon 12, that approximate the oxygen-dependent degradation domain of HIF-1alpha in five cell lines and 28 patients with oral squamous carcinomas. Moreover, we assess for the presence of polymorphisms and mutations in TSC1 and TSC2, to ascertain if dysregulation of such might complement HIF-1alpha expression. Results Denaturing high pressure liquid chromatography (DHPLC analysis on PCR fragments in exon 12 of HIF-1alpha from 28 patients with OSCC revealed that 6 of 28 patients had mismatched heteroduplex patterns. Genomic DNA was extracted from peripheral blood leukocytes and direct sequencing showed that in 5 of the six cases these changes represented polymorphisms while, one case was a somatic mutation. Analyses of TSC1 and TSC2 revealed heteroduplexes in exons: TSC1 exon 17; TSC2 exons 36,40, and 41. The relative levels of HIF-1alpha were significantly greater for tumors possessing a HIF-1alpha polymorphism or mutation within exon 12, whereas tumors possessing a deletion or polymorphism in TSC1/TSC2 displayed a trend for higher levels of HIF-1alpha. Western blot analyses for HIF-1alpha, TSC1 and TSC2 in five SCC cell lines revealed high levels of HIF-1alpha in SCC cells possessing TSC1 and/or TSC2 mutations. Wild-type TSC2 cells targeted with siRNA to TSC2 exhibited increased levels of HIF-1alpha. Transfection of a HIF-1alpha mutant produced higher levels of HIF-1alpha in TSC1/TSC2 mutant cell lines than in wild type cells. TSC1/TSC2 mutant cell lines administered Rapamycin blocked S6 phorphorylation and diminished the levels of HIF-1alpha to those observed in cell lines with wild

  15. Canine Mammary Carcinomas: A Comparative Analysis of Altered Gene Expression

    Directory of Open Access Journals (Sweden)

    Farruk M. Lutful Kabir

    2015-12-01

    Full Text Available Breast cancer represents the second most frequent neoplasm in humans and sexually intact female dogs after lung and skin cancers, respectively. Many similar features in human and dog cancers including, spontaneous development, clinical presentation, tumor heterogeneity, disease progression and response to conventional therapies have supported development of this comparative model as an alternative to mice. The highly conserved similarities between canine and human genomes are also key to this comparative analysis, especially when compared to the murine genome. Studies with canine mammary tumor (CMT models have shown a strong genetic correlation with their human counterparts, particularly in terms of altered expression profiles of cell cycle regulatory genes, tumor suppressor and oncogenes and also a large group of non-coding RNAs or microRNAs (miRNAs. Because CMTs are considered predictive intermediate models for human breast cancer, similarities in genetic alterations and cancer predisposition between humans and dogs have raised further interest. Many cancer-associated genetic defects critical to mammary tumor development and oncogenic determinants of metastasis have been reported and appear to be similar in both species. Comparative analysis of deregulated gene sets or cancer signaling pathways has shown that a significant proportion of orthologous genes are comparably up- or down-regulated in both human and dog breast tumors. Particularly, a group of cell cycle regulators called cyclin-dependent kinase inhibitors (CKIs acting as potent tumor suppressors are frequently defective in CMTs. Interestingly, comparative analysis of coding sequences has also shown that these genes are highly conserved in mammals in terms of their evolutionary divergence from a common ancestor. Moreover, co-deletion and/or homozygous loss of the INK4A/ARF/INK4B (CDKN2A/B locus, encoding three members of the CKI tumor suppressor gene families (p16/INK4A, p14ARF and p15

  16. Reconstruction of the ancestral marsupial karyotype from comparative gene maps

    Science.gov (United States)

    2013-01-01

    Background The increasing number of assembled mammalian genomes makes it possible to compare genome organisation across mammalian lineages and reconstruct chromosomes of the ancestral marsupial and therian (marsupial and eutherian) mammals. However, the reconstruction of ancestral genomes requires genome assemblies to be anchored to chromosomes. The recently sequenced tammar wallaby (Macropus eugenii) genome was assembled into over 300,000 contigs. We previously devised an efficient strategy for mapping large evolutionarily conserved blocks in non-model mammals, and applied this to determine the arrangement of conserved blocks on all wallaby chromosomes, thereby permitting comparative maps to be constructed and resolve the long debated issue between a 2n = 14 and 2n = 22 ancestral marsupial karyotype. Results We identified large blocks of genes conserved between human and opossum, and mapped genes corresponding to the ends of these blocks by fluorescence in situ hybridization (FISH). A total of 242 genes was assigned to wallaby chromosomes in the present study, bringing the total number of genes mapped to 554 and making it the most densely cytogenetically mapped marsupial genome. We used these gene assignments to construct comparative maps between wallaby and opossum, which uncovered many intrachromosomal rearrangements, particularly for genes found on wallaby chromosomes X and 3. Expanding comparisons to include chicken and human permitted the putative ancestral marsupial (2n = 14) and therian mammal (2n = 19) karyotypes to be reconstructed. Conclusions Our physical mapping data for the tammar wallaby has uncovered the events shaping marsupial genomes and enabled us to predict the ancestral marsupial karyotype, supporting a 2n = 14 ancestor. Futhermore, our predicted therian ancestral karyotype has helped to understand the evolution of the ancestral eutherian genome. PMID:24261750

  17. A preliminary study on the expression and clinical value of platelet-derived growth factor BB, hypoxia inducible factor-1α and C-C motif chemokine receptor-2 in peripheral blood during the pathogenesis of Graves' disease.

    Science.gov (United States)

    Liu, Ying; Tang, Jinglan; Hu, Qiaohong; Lu, Kefeng; Hou, Chunjie

    2018-01-01

    Platelet-derived growth factor BB (PDGF-BB) plays an important role in the development of GD (Graves' disease). However, it is still unknown whether PDGF-BB is expressed in peripheral blood and whether the expression of PDGF-BB contributes to GD. We aim to study the expression of PDGF-BB, hypoxia inducible factor (HIF)-1α and C-C motif chemokine receptor (CCR)-2 in peripheral blood of patients with GD and explore its effect and potential mechanism in pathogenesis. 41 patients with GD (GD group) and forty-five healthy people (control group) were chosen. The concentration of PDGF-BB and HIF-1α in peripheral blood specimens were detected and compared between the two groups. The expression of CCR2 in macrophages in the peripheral blood specimens were examined using FCM (Flow Cytometry). Both PDGF-BB and HIF-1α were expressed in human peripheral blood from the two groups. Compared with specimens from healthy people, there were statistically increased concentrations of PDGF-BB and HIF-1α in the GD group (P BB through HIF-1α signal, and the high expression of PDGF-BB may be involved in the pathogenesis of GD.

  18. Comparative analysis of gene expression and regulation of replicative aging associated genes in S. cerevisiae.

    Science.gov (United States)

    Dhami, Sukhraj Pal Singh; Mittal, Nitish; Janga, Sarath Chandra; Roy, Nilanjan

    2011-02-01

    Aging is a multi-factorial and complex phenomenon. Saccharomyces cerevisiae is developed as a model of aging and has been widely studied in order to understand the mechanism of lifespan regulation. A large number of high-throughput studies were conducted to identify the genes which modulate lifespan. These studies provide the list of genes that regulates the lifespan in yeast; however the regulation of these aging associated genes had not been fully understood. In this study, we have shown that deletion of the genes which increase the replicative lifespan (RLS) of yeast show discrete expression patterns when compared with the genes that, on deletion, cause a decrease in lifespan. Expression of longlived (LL) genes decreases as the cell progresses from mid log to stationary phase, whereas expression of shortlived (SL) genes remains unchanged. This distinct expression of LL and SL gene-sets suggests their differential gene regulation. Further analysis of transcriptional regulation by transcription factors and epigenetic regulators (acetylation and methylation) suggests that this differential expression of the two gene-sets is due to their differential epigenetic regulations, rather than regulation by transcription factors. These results accentuate the importance of epigenetic modifications in aging. We deduce that future focused studies on epigenetic modification regulation will help lead to a better understanding of the aging process.

  19. Helicobacter pylori Induced Phosphatidylinositol-3-OH Kinase/mTOR Activation Increases Hypoxia Inducible Factor-1α to Promote Loss of Cyclin D1 and G0/G1 Cell Cycle Arrest in Human Gastric Cells.

    Science.gov (United States)

    Canales, Jimena; Valenzuela, Manuel; Bravo, Jimena; Cerda-Opazo, Paulina; Jorquera, Carla; Toledo, Héctor; Bravo, Denisse; Quest, Andrew F G

    2017-01-01

    Helicobacter pylori (H. pylori) is a human gastric pathogen that has been linked to the development of several gastric pathologies, such as gastritis, peptic ulcer, and gastric cancer. In the gastric epithelium, the bacterium modifies many signaling pathways, resulting in contradictory responses that favor both proliferation and apoptosis. Consistent with such observations, H. pylori activates routes associated with cell cycle progression and cell cycle arrest. H. pylori infection also induces the hypoxia-induced factor HIF-1α, a transcription factor known to promote expression of genes that permit metabolic adaptation to the hypoxic environment in tumors and angiogenesis. Recently, however, also roles for HIF-1α in the repair of damaged DNA and inhibition of gene expression were described. Here, we investigated signaling pathways induced by H. pylori in gastric cells that favor HIF-1α expression and the consequences thereof in infected cells. Our results revealed that H. pylori promoted PI3K/mTOR-dependent HIF-1α induction, HIF-1α translocation to the nucleus, and activity as a transcription factor as evidenced using a reporter assay. Surprisingly, however, transcription of known HIF-1α effector genes evaluated by qPCR analysis, revealed either no change (LDHA and GAPDH), statistically insignificant increases SLC2A1 (GLUT-1) or greatly enhance transcription (VEGFA), but in an HIF-1α-independent manner, as quantified by PCR analysis in cells with shRNA-mediated silencing of HIF-1α. Instead, HIF-1α knockdown facilitated G1/S progression and increased Cyclin D1 protein half-life, via a post-translational pathway. Taken together, these findings link H. pylori-induced PI3K-mTOR activation to HIF-1α induced G0/G1 cell cycle arrest by a Cyclin D1-dependent mechanism. Thus, HIF-1α is identified here as a mediator between survival and cell cycle arrest signaling activated by H. pylori infection.

  20. Heme Oxygenase-1 Attenuates Hypoxia-Induced sFlt-1 and Oxidative Stress in Placental Villi through Its Metabolic Products CO and Bilirubin

    Directory of Open Access Journals (Sweden)

    Eric M. George

    2012-01-01

    Full Text Available One of the most prevalent complications of pregnancy is preeclampsia, a hypertensive disorder which is a leading cause of maternal and perinatal morbidity and premature birth with no effective pharmacological intervention. While the underlying cause is unclear, it is believed that placental ischemia/hypoxia induces the release of factors into the maternal vasculature and lead to widespread maternal endothelial dysfunction. Recently, HO-1 has been shown to downregulate two of these factors, reactive oxygen species and sFlt-1, and we have reported that HO-1 induction attenuates many of the pathological factors of placental ischemia experimentally. Here, we have examined the direct effect of HO-1 and its bioactive metabolites on hypoxia-induced changes in superoxide and sFlt-1 in placental vascular explants and showed that HO-1 and its metabolites attenuate the production of both factors in this system. These findings suggest that the HO-1 pathway may be a promising therapeutic approach for the treatment of preeclampsia.

  1. Reverse Engineering of Gene Regulatory Networks: A Comparative Study

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    Hache Hendrik

    2009-01-01

    Full Text Available Reverse engineering of gene regulatory networks has been an intensively studied topic in bioinformatics since it constitutes an intermediate step from explorative to causative gene expression analysis. Many methods have been proposed through recent years leading to a wide range of mathematical approaches. In practice, different mathematical approaches will generate different resulting network structures, thus, it is very important for users to assess the performance of these algorithms. We have conducted a comparative study with six different reverse engineering methods, including relevance networks, neural networks, and Bayesian networks. Our approach consists of the generation of defined benchmark data, the analysis of these data with the different methods, and the assessment of algorithmic performances by statistical analyses. Performance was judged by network size and noise levels. The results of the comparative study highlight the neural network approach as best performing method among those under study.

  2. Comparative analysis of two acetylcholinesterase genes of Bombyx ...

    African Journals Online (AJOL)

    To compare the sequences and tissue expressions of the two aces between the two species, cDNAs encoding two ace genes were cloned and designated as Bmm-ace1 and Bmm-ace2 from the larvae of the B. mandarina. The amino acid sequence of Bmm-ace1 shared 99.71% homology with its homolog, Bm-ace1, in B.

  3. A comparative analysis of biclustering algorithms for gene expression data.

    Science.gov (United States)

    Eren, Kemal; Deveci, Mehmet; Küçüktunç, Onur; Çatalyürek, Ümit V

    2013-05-01

    The need to analyze high-dimension biological data is driving the development of new data mining methods. Biclustering algorithms have been successfully applied to gene expression data to discover local patterns, in which a subset of genes exhibit similar expression levels over a subset of conditions. However, it is not clear which algorithms are best suited for this task. Many algorithms have been published in the past decade, most of which have been compared only to a small number of algorithms. Surveys and comparisons exist in the literature, but because of the large number and variety of biclustering algorithms, they are quickly outdated. In this article we partially address this problem of evaluating the strengths and weaknesses of existing biclustering methods. We used the BiBench package to compare 12 algorithms, many of which were recently published or have not been extensively studied. The algorithms were tested on a suite of synthetic data sets to measure their performance on data with varying conditions, such as different bicluster models, varying noise, varying numbers of biclusters and overlapping biclusters. The algorithms were also tested on eight large gene expression data sets obtained from the Gene Expression Omnibus. Gene Ontology enrichment analysis was performed on the resulting biclusters, and the best enrichment terms are reported. Our analyses show that the biclustering method and its parameters should be selected based on the desired model, whether that model allows overlapping biclusters, and its robustness to noise. In addition, we observe that the biclustering algorithms capable of finding more than one model are more successful at capturing biologically relevant clusters.

  4. Hypoxia-induced aggressiveness of pancreatic cancer cells is due to increased expression of VEGF, IL-6 and miR-21, which can be attenuated by CDF treatment.

    Directory of Open Access Journals (Sweden)

    Bin Bao

    Full Text Available Hypoxia is known to play critical roles in cell survival, angiogenesis, tumor invasion, and metastasis. Hypoxia mediated over-expression of hypoxia-inducible factor (HIF has been shown to be associated with therapeutic resistance, and contributes to poor prognosis of cancer patients. Emerging evidence suggest that hypoxia and HIF pathways contributes to the acquisition of epithelial-to-mesenchymal transition (EMT, maintenance of cancer stem cell (CSC functions, and also maintains the vicious cycle of inflammation-all which lead to therapeutic resistance. However, the precise molecular mechanism(s by which hypoxia/HIF drives these events are not fully understood. Here, we show, for the first time, that hypoxia leads to increased expression of VEGF, IL-6, and CSC signature genes Nanog, Oct4 and EZH2 consistent with increased cell migration/invasion and angiogenesis, and the formation of pancreatospheres, concomitant with increased expression of miR-21 and miR-210 in human pancreatic cancer (PC cells. The treatment of PC cells with CDF, a novel synthetic compound inhibited the production of VEGF and IL-6, and down-regulated the expression of Nanog, Oct4, EZH2 mRNAs, as well as miR-21 and miR-210 under hypoxia. CDF also led to decreased cell migration/invasion, angiogenesis, and formation of pancreatospheres under hypoxia. Moreover, CDF decreased gene expression of miR-21, miR-210, IL-6, HIF-1α, VEGF, and CSC signatures in vivo in a mouse orthotopic model of human PC. Collectively, these results suggest that the anti-tumor activity of CDF is in part mediated through deregulation of tumor hypoxic pathways, and thus CDF could become a novel, and effective anti-tumor agent for PC therapy.

  5. Floral gene resources from basal angiosperms for comparative genomics research

    Directory of Open Access Journals (Sweden)

    Zhang Xiaohong

    2005-03-01

    Full Text Available Abstract Background The Floral Genome Project was initiated to bridge the genomic gap between the most broadly studied plant model systems. Arabidopsis and rice, although now completely sequenced and under intensive comparative genomic investigation, are separated by at least 125 million years of evolutionary time, and cannot in isolation provide a comprehensive perspective on structural and functional aspects of flowering plant genome dynamics. Here we discuss new genomic resources available to the scientific community, comprising cDNA libraries and Expressed Sequence Tag (EST sequences for a suite of phylogenetically basal angiosperms specifically selected to bridge the evolutionary gaps between model plants and provide insights into gene content and genome structure in the earliest flowering plants. Results Random sequencing of cDNAs from representatives of phylogenetically important eudicot, non-grass monocot, and gymnosperm lineages has so far (as of 12/1/04 generated 70,514 ESTs and 48,170 assembled unigenes. Efficient sorting of EST sequences into putative gene families based on whole Arabidopsis/rice proteome comparison has permitted ready identification of cDNA clones for finished sequencing. Preliminarily, (i proportions of functional categories among sequenced floral genes seem representative of the entire Arabidopsis transcriptome, (ii many known floral gene homologues have been captured, and (iii phylogenetic analyses of ESTs are providing new insights into the process of gene family evolution in relation to the origin and diversification of the angiosperms. Conclusion Initial comparisons illustrate the utility of the EST data sets toward discovery of the basic floral transcriptome. These first findings also afford the opportunity to address a number of conspicuous evolutionary genomic questions, including reproductive organ transcriptome overlap between angiosperms and gymnosperms, genome-wide duplication history, lineage

  6. {sup 1}H NMR metabolomics identification of markers of hypoxia-induced metabolic shifts in a breast cancer model system

    Energy Technology Data Exchange (ETDEWEB)

    Weljie, Aalim M., E-mail: aweljie@ucalgary.ca [University of Calgary, Department of Biological Sciences (Canada); Bondareva, Alla [Department of Comparative Biology and Experimental Medicine (Canada); Zang, Ping [University of Calgary, Department of Chemistry (Canada); Jirik, Frank R. [McCaig Institute for Bone and Joint Health, Department of Biochemistry and Molecular Biology (Canada)

    2011-04-15

    Hypoxia can promote invasive behavior in cancer cells and alters the response to therapeutic intervention as a result of changes in the expression many genes, including genes involved in intermediary metabolism. Although metabolomics technologies are capable of simultaneously measuring a wide range of metabolites in an untargeted manner, these methods have been relatively under utilized in the study of cancer cell responses to hypoxia. Thus, {sup 1}H NMR metabolomics was used to examine the effects of hypoxia in the MDA-MB-231 human breast cancer cell line, both in vitro and in vivo. Cell cultures were compared with respect to their metabolic responses during growth under either hypoxic (1% O{sub 2}) or normoxic conditions. Orthogonal partial least squares discriminant analysis (OPLS-DA) was used to identify a set of metabolites that were responsive to hypoxia. Via intracardiac administration, MDA-MB-231 cells were also used to generate widespread metastatic disease in immuno-compromised mice. Serum metabolite analysis was conducted to compare animals with and without a large tumor burden. Intriguingly, using a cross-plot of the OPLS loadings, both the in vitro and in vivo samples yielded a subset of metabolites that were significantly altered by hypoxia. These included primarily energy metabolites and amino acids, indicative of known alterations in energy metabolism, and possibly protein synthesis or catabolism. The results suggest that the metabolite pattern identified might prove useful as a marker for intra-tumoral hypoxia.

  7. Comparative and genetic analysis of the porcine glucocerebrosidase (GBA) gene.

    Science.gov (United States)

    Stratil, Antonín; Wagenknecht, Daniel; Van Poucke, Mario; Kubícková, Svatava; Bartenschlager, Heinz; Musilová, Petra; Rubes, Jirí; Geldermann, Hermann; Peelman, Luc J

    2004-08-01

    The genomic sequence of the porcine (Sus scrofa) glucocerebrosidase (GBA) gene (approximately 5.7 kb), encoding glucocerebrosidase (glucosylceramidase; acid beta-glucosidase; EC 3.2.1.45), was determined and compared with human (Homo sapiens) GBA and GBAP (pseudogene). The porcine gene harbours 11 exons and 10 introns, and the genomic organization is identical with human GBA. The exon sequences, coding for signal peptide and mature protein, show 81% and 90% sequence identity, respectively, with the corresponding human GBA sequences. Short interspersed elements, SINEs (PREs), are present in introns 2, 4 and 7. There is no evidence of a pseudogene in pig. The deduced protein sequence of GBA consists of 39 amino acids of signal peptide (long form) and 497 amino acids of the mature protein; the latter shows 90% sequence identity with the human protein. Four polymorphisms were observed within the porcine gene: insertion/deletion of one of the two SINEs (PREs) in intron 2 (locus PREA); deletion of a 37- to 39-bp stretch in intron 4 (one direct repeat and 5' end of PRE); deletion of a 47-bp stretch in the middle part of PRE in intron 4 (locus PREB); and single-base transition (C-T) in intron 6 (locus HaeIII-RFLP). GBA was assigned to chromosome 4q21 by FISH and was localized to the same region by linkage analysis and RH mapping, i.e., to the chromosome 4 segment where quantitative trait loci for growth and some carcass traits are located.

  8. 3-Mercaptopyruvate Sulfurtransferase, Not Cystathionine β-Synthase Nor Cystathionine γ-Lyase, Mediates Hypoxia-Induced Migration of Vascular Endothelial Cells.

    Science.gov (United States)

    Tao, Beibei; Wang, Rui; Sun, Chen; Zhu, Yichun

    2017-01-01

    Hypoxia-induced angiogenesis is a common phenomenon in many physiological and patho-physiological processes. However, the potential differential roles of three hydrogen sulfide producing systems cystathionine γ-lyase (CSE)/H2S, cystathionine β-synthase (CBS)/H2S, and 3-mercaptopyruvate sulfurtransferase (MPST)/H2S in hypoxia-induced angiogenesis are still unknown. We found that minor hypoxia (10% oxygen) significantly increased the migration of vascular endothelial cells while hypoxia (8% oxygen) significantly inhibited cell migration. The present study was performed using cells cultured in 10% oxygen. RNA interference was used to block the endogenous generation of hydrogen sulfide by CSE, CBS, or MPST in a vascular endothelial cell migration model in both normoxia and hypoxia. The results showed that CBS had a promoting effect on the migration of vascular endothelial cells cultured in both normoxic and hypoxic conditions. In contrast, CSE had an inhibitory effect on cell migration. MPST had a promoting effect on the migration of vascular endothelial cells cultured in hypoxia; however, it had no effect on the cells cultured in normoxia. Importantly, it was found that the hypoxia-induced increase in vascular endothelial cell migration was mediated by MPST, but not CSE or CBS. The western blot analyses showed that hypoxia significantly increased MPST protein levels, decreased CSE protein levels and did not change CBS levels, suggesting that these three hydrogen sulfide-producing systems respond differently to hypoxic conditions. Interestingly, MPST protein levels were elevated by hypoxia in a bi-phasic manner and MPST mRNA levels increased later than the first stage elevation of the protein levels, implying that the expression of MPST induced by hypoxia was also regulated at a post-transcriptional level. RNA pull-down assay showed that some candidate RNA binding proteins, such as nucleolin and Annexin A2, were dissociated from the 3'-UTR of MPST mRNA in hypoxia

  9. Dinucleotide controlled null models for comparative RNA gene prediction.

    Science.gov (United States)

    Gesell, Tanja; Washietl, Stefan

    2008-05-27

    Comparative prediction of RNA structures can be used to identify functional noncoding RNAs in genomic screens. It was shown recently by Babak et al. [BMC Bioinformatics. 8:33] that RNA gene prediction programs can be biased by the genomic dinucleotide content, in particular those programs using a thermodynamic folding model including stacking energies. As a consequence, there is need for dinucleotide-preserving control strategies to assess the significance of such predictions. While there have been randomization algorithms for single sequences for many years, the problem has remained challenging for multiple alignments and there is currently no algorithm available. We present a program called SISSIz that simulates multiple alignments of a given average dinucleotide content. Meeting additional requirements of an accurate null model, the randomized alignments are on average of the same sequence diversity and preserve local conservation and gap patterns. We make use of a phylogenetic substitution model that includes overlapping dependencies and site-specific rates. Using fast heuristics and a distance based approach, a tree is estimated under this model which is used to guide the simulations. The new algorithm is tested on vertebrate genomic alignments and the effect on RNA structure predictions is studied. In addition, we directly combined the new null model with the RNAalifold consensus folding algorithm giving a new variant of a thermodynamic structure based RNA gene finding program that is not biased by the dinucleotide content. SISSIz implements an efficient algorithm to randomize multiple alignments preserving dinucleotide content. It can be used to get more accurate estimates of false positive rates of existing programs, to produce negative controls for the training of machine learning based programs, or as standalone RNA gene finding program. Other applications in comparative genomics that require randomization of multiple alignments can be considered. SISSIz

  10. Dinucleotide controlled null models for comparative RNA gene prediction

    Directory of Open Access Journals (Sweden)

    Gesell Tanja

    2008-05-01

    Full Text Available Abstract Background Comparative prediction of RNA structures can be used to identify functional noncoding RNAs in genomic screens. It was shown recently by Babak et al. [BMC Bioinformatics. 8:33] that RNA gene prediction programs can be biased by the genomic dinucleotide content, in particular those programs using a thermodynamic folding model including stacking energies. As a consequence, there is need for dinucleotide-preserving control strategies to assess the significance of such predictions. While there have been randomization algorithms for single sequences for many years, the problem has remained challenging for multiple alignments and there is currently no algorithm available. Results We present a program called SISSIz that simulates multiple alignments of a given average dinucleotide content. Meeting additional requirements of an accurate null model, the randomized alignments are on average of the same sequence diversity and preserve local conservation and gap patterns. We make use of a phylogenetic substitution model that includes overlapping dependencies and site-specific rates. Using fast heuristics and a distance based approach, a tree is estimated under this model which is used to guide the simulations. The new algorithm is tested on vertebrate genomic alignments and the effect on RNA structure predictions is studied. In addition, we directly combined the new null model with the RNAalifold consensus folding algorithm giving a new variant of a thermodynamic structure based RNA gene finding program that is not biased by the dinucleotide content. Conclusion SISSIz implements an efficient algorithm to randomize multiple alignments preserving dinucleotide content. It can be used to get more accurate estimates of false positive rates of existing programs, to produce negative controls for the training of machine learning based programs, or as standalone RNA gene finding program. Other applications in comparative genomics that require

  11. Hypoxic transcription gene profiles under the modulation of nitric oxide in nuclear run on-microarray and proteomics

    Directory of Open Access Journals (Sweden)

    Dehne Nathalie

    2009-09-01

    Full Text Available Abstract Background Microarray analysis still is a powerful tool to identify new components of the transcriptosome. It helps to increase the knowledge of targets triggered by stress conditions such as hypoxia and nitric oxide. However, analysis of transcriptional regulatory events remain elusive due to the contribution of altered mRNA stability to gene expression patterns as well as changes in the half-life of mRNAs, which influence mRNA expression levels and their turn over rates. To circumvent these problems, we have focused on the analysis of newly transcribed (nascent mRNAs by nuclear run on (NRO, followed by microarray analysis. Results We identified 196 genes that were significantly regulated by hypoxia, 85 genes affected by nitric oxide and 292 genes induced by the cotreatment of macrophages with both NO and hypoxia. Fourteen genes (Bnip3, Ddit4, Vegfa, Trib3, Atf3, Cdkn1a, Scd1, D4Ertd765e, Sesn2, Son, Nnt, Lst1, Hps6 and Fxyd5 were common to all treatments but with different levels of expression in each group. We observed that 162 transcripts were regulated only when cells were co-treated with hypoxia and NO but not with either treatment alone, pointing to the importance of a crosstalk between hypoxia and NO. In addition, both array and proteomics data supported a consistent repression of hypoxia-regulated targets by NO. Conclusion By eliminating the interference of steady state mRNA in gene expression profiling, we obtained a smaller number of significantly regulated transcripts in our study compared to published microarray data and identified previously unknown hypoxia-induced targets. Gene analysis profiling corroborated the interplay between NO- and hypoxia-induced signaling.

  12. Niclosamide enhances the antitumor effects of radiation by inhibiting the hypoxia-inducible factor-1α/vascular endothelial growth factor signaling pathway in human lung cancer cells.

    Science.gov (United States)

    Xiang, Mei; Chen, Zihong; Yang, Donghong; Li, Haiwen; Zuo, Yufang; Li, Jingjing; Zhang, Wendian; Zhou, Hechao; Jiang, Danxian; Xu, Zumin; Yu, Zhonghua

    2017-08-01

    Lung cancer is one of the leading causes of cancer-associated mortality, worldwide. The overall survival rate remains low, but progress has been made in improving the diagnosis and treatment of lung cancer over the past decades. Niclosamide, a salicylanilide derivative used for the treatment of tapeworm infections, is safe, well tolerated, inexpensive and readily available. Previous studies have identified niclosamide as a potential anticancer agent. The present study demonstrated that niclosamide enhanced the effect of irradiation by inhibiting the hypoxia-inducible factor-1α/vascular endothelial growth factor signaling pathway. These findings suggest that niclosamide may be a promising candidate for clinical evaluation as part of a combined regimen for the treatment of non-small cell lung cancer.

  13. Targeting Hypoxia-Inducible Factor-1α/Pyruvate Dehydrogenase Kinase 1 Axis by Dichloroacetate Suppresses Bleomycin-induced Pulmonary Fibrosis.

    Science.gov (United States)

    Goodwin, Justin; Choi, Hyunsung; Hsieh, Meng-Hsiung; Neugent, Michael L; Ahn, Jung-Mo; Hayenga, Heather N; Singh, Pankaj K; Shackelford, David B; Lee, In-Kyu; Shulaev, Vladimir; Dhar, Shanta; Takeda, Norihiko; Kim, Jung-Whan

    2018-02-01

    Hypoxia has long been implicated in the pathogenesis of fibrotic diseases. Aberrantly activated myofibroblasts are the primary pathological driver of fibrotic progression, yet how various microenvironmental influences, such as hypoxia, contribute to their sustained activation and differentiation is poorly understood. As a defining feature of hypoxia is its impact on cellular metabolism, we sought to investigate how hypoxia-induced metabolic reprogramming affects myofibroblast differentiation and fibrotic progression, and to test the preclinical efficacy of targeting glycolytic metabolism for the treatment of pulmonary fibrosis. Bleomycin-induced pulmonary fibrotic progression was evaluated in two independent, fibroblast-specific, promoter-driven, hypoxia-inducible factor (Hif) 1A knockout mouse models and in glycolytic inhibitor, dichloroacetate-treated mice. Genetic and pharmacological approaches were used to explicate the role of metabolic reprogramming in myofibroblast differentiation. Hypoxia significantly enhanced transforming growth factor-β-induced myofibroblast differentiation through HIF-1α, whereas overexpression of the critical HIF-1α-mediated glycolytic switch, pyruvate dehydrogenase kinase 1 (PDK1) was sufficient to activate glycolysis and potentiate myofibroblast differentiation, even in the absence of HIF-1α. Inhibition of the HIF-1α/PDK1 axis by genomic deletion of Hif1A or pharmacological inhibition of PDK1 significantly attenuated bleomycin-induced pulmonary fibrosis. Our findings suggest that HIF-1α/PDK1-mediated glycolytic reprogramming is a critical metabolic alteration that acts to promote myofibroblast differentiation and fibrotic progression, and demonstrate that targeting glycolytic metabolism may prove to be a potential therapeutic strategy for the treatment of pulmonary fibrosis.

  14. Reciprocal Regulation of Hypoxia-Inducible Factor 2α and GLI1 Expression Associated With the Radioresistance of Renal Cell Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jiancheng [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Wu, Kaijie [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Gao, Dexuan [Department of Urology, Shandong Provincial Hospital affiliated with Shandong University, Ji' nan (China); Zhu, Guodong; Wu, Dapeng; Wang, Xinyang; Chen, Yule; Du, Yuefeng; Song, Wenbin; Ma, Zhenkun [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Authement, Craig; Saha, Debabrata [Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Hsieh, Jer-Tsong, E-mail: jt.hsieh@utsouthwestern.edu [Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); He, Dalin, E-mail: dalinhe@yahoo.com [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China)

    2014-11-15

    Purpose: Renal cell carcinoma (RCC) is often considered a radioresistant tumor, but the molecular mechanism underlying its radioresistance is poorly understood. This study explored the roles of hypoxia-inducible factor 2α (HIF2α) and sonic hedgehog (SHH)-GLI1 signaling in mediating the radioresistance of RCC cells and to unveil the interaction between these 2 signaling pathways. Methods and Materials: The activities of SHH-GLI1 signaling pathway under normoxia and hypoxia in RCC cells were examined by real-time polymerase chain reaction, Western blot, and luciferase reporter assay. The expression of HIF2α and GLI1 in RCC patients was examined by immunohistochemistry, and their correlation was analyzed. Furthermore, RCC cells were treated with HIF2α-specific shRNA (sh-HIF2α), GLI1 inhibitor GANT61, or a combination to determine the effect of ionizing radiation (IR) on RCC cells based on clonogenic assay and double-strand break repair assay. Results: RCC cells exhibited elevated SHH-GLI1 activities under hypoxia, which was mediated by HIF2α. Hypoxia induced GLI1 activation through SMO-independent pathways that could be ablated by PI3K inhibitor or MEK inhibitor. Remarkably, the SHH-GLI1 pathway also upregulated HIF2α expression in normoxia. Apparently, there was a positive correlation between HIF2α and GLI1 expression in RCC patients. The combination of sh-HIF2α and GLI1 inhibitor significantly sensitized RCC cells to IR. Conclusions: Cross-talk between the HIF2α and SHH-GLI1 pathways was demonstrated in RCC. Cotargeting these 2 pathways, significantly sensitizing RCC cells to IR, provides a novel strategy for RCC treatment.

  15. Baicalin Inhibits Hypoxia-Induced Pulmonary Artery Smooth Muscle Cell Proliferation via the AKT/HIF-1α/p27-Associated Pathway

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2014-05-01

    Full Text Available Baicalin, a flavonoid compound purified from the dry roots of Scutellaria baicalensis Georgi, has been shown to possess various pharmacological actions. Previous studies have revealed that baicalin inhibits the growth of cancer cells through the induction of apoptosis. Pulmonary arterial hypertension (PAH is a devastating disease characterized by enhanced pulmonary artery smooth muscle cell (PASMCs proliferation and suppressed apoptosis. However, the potential mechanism of baicalin in the regulation of PASMC proliferation and the prevention of cardiovascular diseases remains unexplored. To test the effects of baicalin on hypoxia, we used rats treated with or without baicalin (100 mg·kg−1 each rat at the beginning of the third week after hypoxia. Hemodynamic and pulmonary pathomorphology data showed that right ventricular systolic pressures (RVSP, the weight of the right ventricle/left ventricle plus septum (RV/LV + S ratio and the medial width of pulmonary arterioles were much higher in chronic hypoxia. However, baicalin treatment repressed the elevation of RVSP, RV/LV + S and attenuated the pulmonary vascular structure remodeling (PVSR of pulmonary arterioles induced by chronic hypoxia. Additionally, baicalin (10 and 20 μmol·L−1 treatment suppressed the proliferation of PASMCs and attenuated the expression of hypoxia-inducible factor-α (HIF-α under hypoxia exposure. Meanwhile, baicalin reversed the hypoxia-induced reduction of p27 and increased AKT/protein kinase B phosphorylation p-AKT both in vivo and in vitro. These results suggested that baicalin could effectively attenuate PVSR and hypoxic pulmonary hypertension.

  16. Radiosensitization of normoxic and hypoxic h1339 lung tumor cells by heat shock protein 90 inhibition is independent of hypoxia inducible factor-1α.

    Directory of Open Access Journals (Sweden)

    Daniela Schilling

    Full Text Available Ionizing irradiation is a commonly accepted treatment modality for lung cancer patients. However, the clinical outcome is hampered by normal tissue toxicity and tumor hypoxia. Since tumors often have higher levels of active heat shock protein 90 (Hsp90 than normal tissues, targeting of Hsp90 might provide a promising strategy to sensitize tumors towards irradiation. Hsp90 client proteins include oncogenic signaling proteins, cell cycle activators, growth factor receptors and hypoxia inducible factor-1α (HIF-1α. Overexpression of HIF-1α is assumed to promote malignant transformation and tumor progression and thus might reduce the accessibility to radiotherapy.Herein, we describe the effects of the novel Hsp90 inhibitor NVP-AUY922 and 17-allylamino-17-demethoxygeldanamycin (17-AAG, as a control, on HIF-1α levels and radiosensitivity of lung carcinoma cells under normoxic and hypoxic conditions. NVP-AUY922 exhibited a similar biological activity to that of 17-AAG, but at only 1/10 of the dose. As expected, both inhibitors reduced basal and hypoxia-induced HIF-1α levels in EPLC-272H lung carcinoma cells. However, despite a down-regulation of HIF-1α upon Hsp90 inhibition, sensitivity towards irradiation remained unaltered in EPLC-272H cells under normoxic and hypoxic conditions. In contrast, treatment of H1339 lung carcinoma cells with NVP-AUY922 and 17-AAG resulted in a significant up-regulation of their initially high HIF-1α levels and a concomitant increase in radiosensitivity.In summary, our data show a HIF-1α-independent radiosensitization of normoxic and hypoxic H1339 lung cancer cells by Hsp90 inhibition.

  17. Comparative genomics of free-living Gammaproteobacteria: pathogenesis-related genes or interaction-related genes?

    Science.gov (United States)

    Vázquez-Rosas-Landa, Mirna; Ponce-Soto, Gabriel Yaxal; Eguiarte, Luis E; Souza, V

    2017-07-31

    Bacteria have numerous strategies to interact with themselves and with their environment, but genes associated with these interactions are usually cataloged as pathogenic. To understand the role that these genes have not only in pathogenesis but also in bacterial interactions, we compared the genomes of eight bacteria from human-impacted environments with those of free-living bacteria from the Cuatro Ciénegas Basin (CCB), a relatively pristine oligotrophic site. Fifty-one genomes from CCB bacteria, including Pseudomonas, Vibrio, Photobacterium and Aeromonas, were analyzed. We found that the CCB strains had several virulence-related genes, 15 of which were common to all strains and were related to flagella and chemotaxis. We also identified the presence of Type III and VI secretion systems, which leads us to propose that these systems play an important role in interactions among bacterial communities beyond pathogenesis. None of the CCB strains had pathogenicity islands, despite having genes associated with antibiotics. Integrons were rare, while CRISPR elements were common. The idea that pathogenicity-related genes in many cases form part of a wider strategy used by bacteria to interact with other organisms could help us to understand the role of pathogenicity-related elements in an ecological and evolutionary framework leading toward a more inclusive One Health concept. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Environmental Enrichment Prevent the Juvenile Hypoxia-Induced Developmental Loss of Parvalbumin-Immunoreactive Cells in the Prefrontal Cortex and Neurobehavioral Alterations Through Inhibition of NADPH Oxidase-2-Derived Oxidative Stress.

    Science.gov (United States)

    Zhang, Mingqiang; Wu, Jing; Huo, Lan; Luo, Liang; Song, Xi; Fan, Fei; Lu, Yiming; Liang, Dong

    2016-12-01

    We compared the expression of phenotype of parvalbumin (PV)-immunoreactive cells in the prefrontal cortex (PFC) of juvenile rats reared in enriched environment (EE) after daily intermittent hypoxia (IH) exposure to those reared in standard environment (SE) and investigated the involvement of NADPH oxidase-2 (NOX2)-derived oxidative stress in the IH-induced neurodevelopmental and neurobehavioral consequences in a juvenile rat model of obstructive sleep apnea. Postnatal day 21 (P21) rats were exposed to IH or room air 8 h daily for 14 consecutive days. After the daily exposure, the rats were raised in SE or EE. In the PFC of P34 rats, we determined the impact (i) of IH exposures on NOX2-derived oxidative stress and PV immunoreactivity, (ii) of pharmacological NOX2 inhibition on IH-induced oxidative stress and PV immunoreactivity, and (iii) of EE on the IH-induced oxidative stress and PV immunoreactivity. Behavioral testing of psychiatric anxiety was carried out consecutively in the open-field test and elevated plus maze at P35 and P36. The results showed IH exposures increased NOX2 expression in the PFC of P34 rats, which was accompanied with elevation of NOX activity and indirect markers of oxidative stress (4-HNE). IH exposures increased 4-HNE immunoreactivity in cortical PV cells, which was accompanied with reduction of PV immunoreactivity. Treatment of IH rats with the antioxidant/NOX inhibitor apocynin prevented the PV cells loss in the PFC and reversed the IH-induced psychiatric anxiety. EE attenuated the NOX2-derived oxidative stress and reversed the PV-immunoreactivity reduction in the PFC induced by IH. Our data suggest that EE might prevent the juvenile hypoxia-induced developmental loss of PV cells in the PFC and attenuate the neurobehavioral alterations through inhibition of NOX2-derived oxidative stress.

  19. Priming of hypoxia-inducible factor by neuronal nitric oxide synthase is essential for adaptive responses to severe anemia.

    Science.gov (United States)

    Tsui, Albert K Y; Marsden, Philip A; Mazer, C David; Adamson, S Lee; Henkelman, R Mark; Ho, J J David; Wilson, David F; Heximer, Scott P; Connelly, Kim A; Bolz, Steffen-Sebastian; Lidington, Darcy; El-Beheiry, Mostafa H; Dattani, Neil D; Chen, Kevin M; Hare, Gregory M T

    2011-10-18

    Cells sense and respond to changes in oxygen concentration through gene regulatory processes that are fundamental to survival. Surprisingly, little is known about how anemia affects hypoxia signaling. Because nitric oxide synthases (NOSs) figure prominently in the cellular responses to acute hypoxia, we defined the effects of NOS deficiency in acute anemia. In contrast to endothelial NOS or inducible NOS deficiency, neuronal NOS (nNOS)(-/-) mice demonstrated increased mortality during anemia. Unlike wild-type (WT) animals, anemia did not increase cardiac output (CO) or reduce systemic vascular resistance (SVR) in nNOS(-/-) mice. At the cellular level, anemia increased expression of HIF-1α protein and HIF-responsive mRNA levels (EPO, VEGF, GLUT1, PDK1) in the brain of WT, but not nNOS(-/-) mice, despite comparable reductions in tissue PO(2). Paradoxically, nNOS(-/-) mice survived longer during hypoxia, retained the ability to regulate CO and SVR, and increased brain HIF-α protein levels and HIF-responsive mRNA transcripts. Real-time imaging of transgenic animals expressing a reporter HIF-α(ODD)-luciferase chimeric protein confirmed that nNOS was essential for anemia-mediated increases in HIF-α protein stability in vivo. S-nitrosylation effects the functional interaction between HIF and pVHL. We found that anemia led to nNOS-dependent S-nitrosylation of pVHL in vivo and, of interest, led to decreased expression of GSNO reductase. These findings identify nNOS effects on the HIF/pVHL signaling pathway as critically important in the physiological responses to anemia in vivo and provide essential mechanistic insight into the differences between anemia and hypoxia.

  20. Comparative genomics of the relationship between gene structure and expression

    NARCIS (Netherlands)

    Ren, X.

    2006-01-01

    The relationship between the structure of genes and their expression is a relatively new aspect of genome organization and regulation. With more genome sequences and expression data becoming available, bioinformatics approaches can help the further elucidation of the relationships between gene

  1. Comparative analysis of gene expression profiles of OPN signalling ...

    Indian Academy of Sciences (India)

    The results showed that 23, 33, 59 and 74 genes were significantly changed in the above four kinds of liver diseases, respectively. H-clustering analysis showed that the expression profiles of OPN signalling-related genes were notably different in four kinds of liver diseases. Subsequently, a total of above-mentioned 147 ...

  2. Comparative mapping reveals similar linkage of functional genes to ...

    Indian Academy of Sciences (India)

    ... B. napus homologues were located in similar yield-related QTL between species. Our results indicate that homologous genes between O. sativa and B. napus may have consistent function and control similar traits, which may be helpful for agronomic gene characterization in B. napus based on what is known in O. sativa.

  3. Comparative Screening of Digestion Tract Toxic Genes in Proteus mirabilis.

    Science.gov (United States)

    Shi, Xiaolu; Lin, Yiman; Qiu, Yaqun; Li, Yinghui; Jiang, Min; Chen, Qiongcheng; Jiang, Yixiang; Yuan, Jianhui; Cao, Hong; Hu, Qinghua; Huang, Shenghe

    2016-01-01

    Proteus mirabilis is a common urinary tract pathogen, and may induce various inflammation symptoms. Its notorious ability to resist multiple antibiotics and to form urinary tract stones makes its treatment a long and painful process, which is further challenged by the frequent horizontal gene transferring events in P. mirabilis genomes. Three strains of P. mirabilis C02011/C04010/C04013 were isolated from a local outbreak of a food poisoning event in Shenzhen, China. Our hypothesis is that new genes may have been acquired horizontally to exert the digestion tract infection and toxicity. The functional characterization of these three genomes shows that each of them independently acquired dozens of virulent genes horizontally from the other microbial genomes. The representative strain C02011 induces the symptoms of both vomit and diarrhea, and has recently acquired a complete type IV secretion system and digestion tract toxic genes from the other bacteria.

  4. The histone demethylases JMJD1A and JMJD2B are transcriptional targets of hypoxia-inducible factor HIF

    DEFF Research Database (Denmark)

    Beyer, Sophie; Kristensen, Malene Maag; Jensen, Kim Steen

    2008-01-01

    Posttranslational histone modifications serve to store epigenetic information and control both nucleosome assembly and recruitment of non-histone proteins. Histone methylation occurs on arginine and lysine residues and is involved in the regulation of gene transcription. A dynamic control of thes...

  5. A possible therapeutic potential of quercetin through inhibition of μ-calpain in hypoxia induced neuronal injury: a molecular dynamics simulation study

    Directory of Open Access Journals (Sweden)

    Anand Kumar Pandey

    2016-01-01

    Full Text Available The neuroprotective property of quercetin is well reported against hypoxia and ischemia in past studies. This property of quercetin lies in its antioxidant property with blood-brain barrier permeability and anti-inflammatory capabilities. µ-Calpain, a calcium ion activated intracellular cysteine protease causes serious cellular insult, leading to cell death in various pathological conditions including hypoxia and ischemic stroke. Hence, it may be considered as a potential drug target for the treatment of hypoxia induced neuronal injury. As the inhibitory property of µ-calpain is yet to be explored in details, hence, in the present study, we investigated the interaction of quercetin with µ-calpain through a molecular dynamics simulation study as a tool through clarifying the molecular me