A new HIF-1 alpha variant induced by zinc ion suppresses HIF-1-mediated hypoxic responses

2001 ◽  
Vol 114 (22) ◽  
pp. 4051-4061
Author(s):  
Yang-Sook Chun ◽  
Eunjoo Choi ◽  
Eun-Jin Yeo ◽  
Jong Ho Lee ◽  
Myung-Suk Kim ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Consensus Sequence ◽  
Hypoxia Inducible Factor ◽  
Zinc Ion ◽  
Dominant Negative ◽  
Hypoxia Inducible Factor 1 ◽  
Aryl Hydrocarbon ◽  
Hypoxic Conditions ◽  
Alpha Variant ◽  
Inducible Genes

The expressions of hypoxia-inducible genes are upregulated by hypoxia-inducible factor 1 (HIF-1), which is a heterodimer of HIF-1α and HIF-1β/ARNT (aryl hydrocarbon receptor nuclear transporter). Under hypoxic conditions, HIF-1α becomes stabilized and both HIF-1α and ARNT are translocated into the nucleus and codimerized, binding to the HIF-1 consensus sequence and transactivating hypoxia-inducible genes. Other than hypoxia, cobalt and nickel, which can substitute for iron in the ferroprotein, induce the stabilization of HIF-1α and the activation of HIF-1. We found previously that, although zinc, another example of a metal substitute for iron, stabilized HIF-1α, it suppressed the formation of HIF-1 by blocking the nuclear translocation of ARNT. Here, we identify a new spliced variant of human HIF-1α that is induced by zinc. The isoform lacks the 12th exon, which produced a frame-shift and gave a shorter form of HIF-1α (557 amino acids), designated HIF-1αZ (HIF-1α induced by Zn). This moiety was found to inhibit HIF-1 activity and reduce mRNA expressions of the hypoxia-inducible genes. It blocked the nuclear translocation of ARNT but not that of endogenous HIF-1α, and was associated with ARNT in the cytosol. These results suggest that HIF-1αZ functions as a dominant-negative isoform of HIF-1 by sequestering ARNT in the cytosol. In addition, the generation of HIF-1αZ seems to be responsible for the inhibitory effects of the zinc ion on HIF-1-mediated hypoxic responses, because the expressed HIF-1αZ behaved in the same manner as zinc in terms of inhibited HIF-1 activity and ARNT translocation.

scholarly journals Induction and nuclear translocation of hypoxia-inducible factor-1 (HIF-1): heterodimerization with ARNT is not necessary for nuclear accumulation of HIF-1alpha

1999 ◽  
Vol 112 (8) ◽  
pp. 1203-1212 ◽  
Author(s):  
D. Chilov ◽  
G. Camenisch ◽  
I. Kvietikova ◽  
U. Ziegler ◽  
M. Gassmann ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Hypoxia Inducible Factor ◽  
Embryonic Stem ◽  
Nuclear Accumulation ◽  
Nuclear Compartment ◽  
Hypoxia Inducible Factor 1 ◽  
Aryl Hydrocarbon ◽  
Oxygen Homeostasis ◽  
Nuclear Extracts ◽  
Stable Association

Hypoxia-inducible factor-1 (HIF-1) is a master regulator of mammalian oxygen homeostasis. HIF-1 consists of two subunits, HIF-1alpha and the aryl hydrocarbon receptor nuclear translocator (ARNT). Whereas hypoxia prevents proteasomal degradation of HIF-1alpha, ARNT expression is thought to be oxygen-independent. We and others previously showed that ARNT is indispensable for HIF-1 DNA-binding and transactivation function. Here, we have used ARNT-mutant mouse hepatoma and embryonic stem cells to examine the requirement of ARNT for accumulation and nuclear translocation of HIF-1alpha in hypoxia. As shown by immunofluorescence, HIF-1alpha accumulation in the nucleus of hypoxic cells was independent of the presence of ARNT, suggesting that nuclear translocation is intrinsic to HIF-1alpha. Co-immunoprecipitation of HIF-1alpha together with ARNT could be performed in nuclear extracts but not in cytosolic fractions, implying that formation of the HIF-1 complex occurs in the nucleus. A proteasome inhibitor and a thiol-reducing agent could mimic hypoxia by inducing HIF-1alpha in the nucleus, indicating that escape from proteolytic degradation is sufficient for accumulation and nuclear translocation of HIF-1alpha. During biochemical separation, both HIF-1alpha and ARNT tend to leak from the nuclei in the absence of either subunit, suggesting that heterodimerization is required for stable association within the nuclear compartment. Nuclear stabilization of the heterodimer might also explain the hypoxically increased total cellular ARNT levels observed in some of the cell lines examined.

scholarly journals Interleukin 1 induces hypoxia-inducible factor 1 in human gingival and synovial fibroblasts

2000 ◽  
Vol 350 (1) ◽  
pp. 307-312 ◽  
Author(s):  
Ruth D. THORNTON ◽  
Pamela LANE ◽  
Ruth C. BORGHAEI ◽  
Elizabeth A. PEASE ◽  
Jaime CARO ◽  
...  
Keyword(s):  
Inflammatory Diseases ◽  
Interleukin 1 ◽  
Consensus Sequence ◽  
Hypoxia Inducible Factor ◽  
Synovial Fibroblasts ◽  
Consensus Binding Site ◽  
Hypoxia Inducible Factor 1 ◽  
Aryl Hydrocarbon ◽  
Factor Α ◽  
Endothelial Growth Factor

Rheumatoid arthritis and periodontitis are inflammatory diseases modulated by proinflammatory cytokines [e.g. interleukin (IL-1) 1 and tumour necrosis factor α], which activate local fibroblasts to do the following: (1) proliferate, (2) induce gene expression and (3) produce destructive metalloproteinases. Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric transcription factor (composed of HIF-1α and HIF-1β/aryl hydrocarbon receptor nuclear transporter) that is modulated by hypoxia. HIF-1 binds to and induces several genes containing an HIF-1 consensus-binding site, including vascular endothelial growth factor and several glycolytic enzymes. Through differential screening of a human synovial fibroblast cDNA library, we identified HIF-1α as a clone up-regulated by IL-1. The mRNA for HIF-1α subunit was increased 3–4-fold by Northern blot analysis after cells had been incubated for 3h in the presence of IL-1. In addition, IL-1 increased the binding of the heterodimer HIF-1 to the HIF consensus sequence. These results suggest that HIF-1 might have a role in inflammation, possibly in attempting to re-establish homoeostasis.

scholarly journals The Regulation of Hypoxic Genes by Calcium Involves c-Jun/AP-1, Which Cooperates with Hypoxia-Inducible Factor 1 in Response to Hypoxia

2002 ◽  
Vol 22 (6) ◽  
pp. 1734-1741 ◽  
Author(s):  
Konstantin Salnikow ◽  
Thomas Kluz ◽  
Max Costa ◽  
David Piquemal ◽  
Zoya N. Demidenko ◽  
...  
Keyword(s):  
Gene Expression ◽  
Kinase Inhibitor ◽  
Regulation Of Gene Expression ◽  
Hypoxia Inducible Factor ◽  
Dominant Negative ◽  
Activator Protein 1 ◽  
Hypoxia Inducible Factor 1 ◽  
Intracellular Ca ◽  
Inducible Genes ◽  
Endothelial Growth Factor

ABSTRACT Hypoxia causes the accumulation of the transcription factor hypoxia-inducible factor 1 (HIF-1), culminating in the expression of hypoxia-inducible genes such as those for vascular endothelial growth factor (VEGF) and NDRG-1/Cap43. Previously, we have demonstrated that intracellular calcium (Ca2+) is required for the expression of hypoxia-inducible genes. Here we found that, unlike with hypoxia or hypoxia-mimicking conditions, the elevation of intracellular Ca2+ neither induced the HIF-1α protein nor stimulated HIF-1-dependent transcription. Furthermore, the elevation of intracellular Ca2+ induced NDRG-1/Cap43 mRNA in HIF-1α-deficient cells. It also increased levels of c-Jun protein, causing its phosphorylation. The protein kinase inhibitor K252a abolished c-Jun induction and activator protein 1 (AP-1)-dependent reporter expression caused by Ca2+ ionophore or hypoxia. K252a also significantly decreased hypoxia-induced VEGF and NDRG-1/Cap43 gene expression in both human and mouse cells. Using a set of deletion VEGF-Luc promoter constructs, we found that both HIF-1 and two AP-1 sites contribute to hypoxia-mediated induction of transcription. In contrast, only AP-1 sites contributed to Ca2+-mediated VEGF-Luc induction. A dominant-negative AP-1 prevented Ca2+-dependent transcription and partially impaired hypoxia-mediated transcription. In addition, dominant-negative AP-1 diminished the expression of the NDRG-1/Cap43 gene following hypoxia. We conclude that during hypoxia, an increase in intracellular Ca2+ activates a HIF-1-independent signaling pathway that involves AP-1-dependent transcription. Cooperation between the HIF-1 and AP-1 pathways allows fine regulation of gene expression during hypoxia.

A dominant-negative isoform lacking exons 11 and 12 of the human hypoxia-inducible factor-1α gene

2002 ◽  
Vol 362 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Yang-Sook CHUN ◽  
Eunjoo CHOI ◽  
Tae-You KIM ◽  
Myung-Suk KIM ◽  
Jong-Wan PARK
Keyword(s):  
Nuclear Translocation ◽  
Protein A ◽  
Hypoxia Inducible Factor ◽  
Dominant Negative ◽  
Cobalt Ions ◽  
Hypoxia Inducible Factor 1Α ◽  
Helix Loop Helix ◽  
Transactivation Domains ◽  
Localization Signal ◽  
Inducible Genes

Hypoxia-inducible factor-1α (HIF-1α), a member of the transcription family characterized by a basic helix-loop-helix (bHLH) domain and a PAS domain, regulates the transcription of hypoxia-inducible genes involved in erythropoiesis, vascular remodelling and glucose/energy metabolism. It contains bHLH/PAS domains in the N-terminal half, and a nuclear localization signal (NLS) and two transactivation domains (TADs) in the C-terminal half. It also has an oxygen-dependent degradation (ODD) domain, which is required to degrade HIF-1α protein by the ubiquitin—proteasome pathway. In this study, we identified a new alternatively spliced variant of human HIF-1α mRNA, which lacked both exons 11 and 12, producing a frame shift and giving a shorter form of HIF-1α. In the corresponding protein, a part of the ODD domain, both TADs and the C-terminal NLS motif were missing. Expression of endogenous HIF-1α variant protein was identified using immunoprecipitation and immunoblotting methods. The expressed HIF-1α variant exhibited neither the activity of transactivation nor hypoxia-induced nuclear translocation. In contrast with HIF-1α, the variant was strikingly stable in normoxic conditions and not up-regulated to such an extent by hypoxia, cobalt ions or desferrioxamine. It was also demonstrated that the HIF-1α variant competed with endogenous HIF-1α and suppressed HIF-1 activity, resulting in the down-regulation of mRNA expression of hypoxia-inducible genes. The association of the variant and arylhydrocarbon receptor nuclear translocator in the cytoplasm may be related to the inhibition of HIF-1 activity. It is assumed that this isoform preserves the balance between aerobic and anaerobic metabolism by counteracting the overaction of HIF-1α.

scholarly journals Multi-Omic Meta-Analysis of Transcriptomes and the Bibliome Uncovers Novel Hypoxia-Inducible Genes

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 582
Author(s):  
Yoko Ono ◽  
Hidemasa Bono
Keyword(s):  
Meta Analysis ◽  
Hypoxia Inducible Factor ◽  
Data Driven ◽  
Similarity Coefficients ◽  
Hypoxia Inducible Factor 1 ◽  
Response System ◽  
Inducible Genes ◽  
The Relationship ◽  
G Protein Coupled ◽  
Sufficient Oxygen

Hypoxia is a condition in which cells, tissues, or organisms are deprived of sufficient oxygen supply. Aerobic organisms have a hypoxic response system, represented by hypoxia-inducible factor 1-α (HIF1A), to adapt to this condition. Due to publication bias, there has been little focus on genes other than well-known signature hypoxia-inducible genes. Therefore, in this study, we performed a meta-analysis to identify novel hypoxia-inducible genes. We searched publicly available transcriptome databases to obtain hypoxia-related experimental data, retrieved the metadata, and manually curated it. We selected the genes that are differentially expressed by hypoxic stimulation, and evaluated their relevance in hypoxia by performing enrichment analyses. Next, we performed a bibliometric analysis using gene2pubmed data to examine genes that have not been well studied in relation to hypoxia. Gene2pubmed data provides information about the relationship between genes and publications. We calculated and evaluated the number of reports and similarity coefficients of each gene to HIF1A, which is a representative gene in hypoxia studies. In this data-driven study, we report that several genes that were not known to be associated with hypoxia, including the G protein-coupled receptor 146 gene, are upregulated by hypoxic stimulation.

scholarly journals Hypoxia-Induced Gene Expression Occurs Solely through the Action of Hypoxia-Inducible Factor 1α (HIF-1α): Role of Cytoplasmic Trapping of HIF-2α

2003 ◽  
Vol 23 (14) ◽  
pp. 4959-4971 ◽  
Author(s):  
Sang-ki Park ◽  
Agnes M. Dadak ◽  
Volker H. Haase ◽  
Lucrezia Fontana ◽  
Amato J. Giaccia ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Activity ◽  
Hypoxia Inducible Factor ◽  
Low Oxygen ◽  
Hypoxic Conditions ◽  
Show Evidence ◽  
Dependent Protein ◽  
A Cell ◽  
Cell Type Specific ◽  
Inducible Genes

ABSTRACT The hypoxia-inducible factors 1α (HIF-1α) and 2α (HIF-2α) have extensive structural homology and have been identified as key transcription factors responsible for gene expression in response to hypoxia. They play critical roles not only in normal development, but also in tumor progression. Here we report on the differential regulation of protein expression and transcriptional activity of HIF-1α and -2α by hypoxia in immortalized mouse embryo fibroblasts (MEFs). We show that oxygen-dependent protein degradation is restricted to HIF-1α, as HIF-2α protein is detected in MEFs regardless of oxygenation and is localized primarily to the cytoplasm. Endogenous HIF-2α remained transcriptionally inactive under hypoxic conditions; however, ectopically overexpressed HIF-2α translocated into the nucleus and could stimulate expression of hypoxia-inducible genes. We show that the factor inhibiting HIF-1 can selectively inhibit the transcriptional activity of HIF-1α but has no effect on HIF-2α-mediated transcription in MEFs. We propose that HIF-2α is not a redundant transcription factor of HIF-1α for hypoxia-induced gene expression and show evidence that there is a cell type-specific modulator(s) that enables selective activation of HIF-1α but not HIF-2α in response to low-oxygen stress.

scholarly journals Neuroglobin Regulates Hypoxic Response of Neuronal Cells through Hif-1α- and Nrf2-mediated Mechanism

2012 ◽  
Vol 32 (6) ◽  
pp. 1046-1060 ◽  
Author(s):  
Kalpana B Hota ◽  
Sunil K Hota ◽  
Ravi B Srivastava ◽  
Shashi B Singh
Keyword(s):  
Cytochrome C ◽  
Acute Hypoxia ◽  
Neuronal Cells ◽  
Hypoxia Inducible Factor ◽  
Redox Status ◽  
Related Factor ◽  
Cytochrome C Release ◽  
Hypoxia Inducible Factor 1 ◽  
Hypoxic Conditions ◽  
Cellular Antioxidants

Oxygen sensing in hypoxic neurons has been classically attributed to cytochrome c oxidase and prolyl-4-hydroxylases and involves stabilization of transcription factors, hypoxia-inducible factor-1 α (Hif-1 α) and nuclear factor erythroid 2-related factor 2 (Nrf2) that mediate survival responses. On the contrary, release of cytochrome c into the cytosol during hypoxic stress triggers apoptosis in neuronal cells. We, here advocate that the redox state of neuroglobin (Ngb) could regulate both Hif-1 α and Nrf2 stabilization and cytochrome c release during hypoxia. The hippocampal regions showing higher expression of Ngb were less susceptible to global hypoxia-mediated neurodegeneration. During normoxia, Ngb maintained cytochrome c in the reduced state and prevented its release from mitochondria by using cellular antioxidants. Greater turnover of oxidized cytochrome c and increased utilization of cellular antioxidants during acute hypoxia altered cellular redox status and stabilized Hif-1 α and Nrf2 through Ngb-mediated mechanism. Chronic hypoxia, however, resulted in oxidation and degradation of Ngb, accumulation of ferric ions and release of cytochrome c that triggered apoptosis. Administration of N-acetyl-cysteine during hypoxic conditions improved neuronal survival by preventing Ngb oxidation and degradation. Taken together, these results establish a role for Ngb in regulating both the survival and apoptotic mechanisms associated with hypoxia.

scholarly journals Hypoxia Rapidly Induces the Expression of Cardiomyogenic Factors in Human Adipose-Derived Adherent Stromal Cells

2019 ◽  
Vol 8 (8) ◽  
pp. 1231
Author(s):  
Choi ◽  
Moon ◽  
Jung ◽  
Lim ◽  
Lee ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stromal Cells ◽  
Hypoxia Inducible Factor ◽  
In Vivo Studies ◽  
Hypoxic Stress ◽  
Differentiation Markers ◽  
Hypoxia Inducible Factor 1 ◽  
Hypoxic Conditions ◽  
Fibroblast Growth Factor 19

Background: The efficacy of interstitial vascular fraction (SVF) transplantation in the treatment of heart disease has been proven in a variety of in vivo studies. In a previous study, we found that bone marrow-derived mesenchymal stem cells (BM-MSCs) altered their expression of several cardiomyogenic factors under hypoxic conditions. Methods: We hypothesized that hypoxia may also induce obtained adipose-derived adherent stromal cells (ADASs) from SVFs and adipose-derived stem cells (ASCs) to differentiate into cardiomyocytes and/or cells with comparable phenotypes. We examined the differentiation markers of cell lineages in ADASs and ASCs according to time by hypoxic stress and found that only ADASs expressed cardiomyogenic markers within 24 hours under hypoxic conditions in association with the expression of hypoxia-inducible factor 1-α (HIF-1α). Results: Differentially secreted proteins in a conditioned medium (CM) from ASCs and ADASs under normoxic or hypoxic conditions were detected using an antibody assay and may be associated with a dramatic increase in the expression of cardiomyogenic markers in only ADASs. Furthermore, the cardiomyogenic factors were expressed more rapidly in ADASs than in ASCs under hypoxic conditions in association with the expression of HIF-1α, and angiogenin, fibroblast growth factor-19 (FGF-19) and/or macrophage inhibitory factor (MIF) are related. Conclusions: These results provide new insights into the applicability of ADASs preconditioned by hypoxic stress in cardiac diseases.

Transcriptional regulation of plasminogen activator inhibitor-1 expression by insulin-like growth factor-1 via MAP kinases and hypoxia-inducible factor-1 in HepG2 cells

2005 ◽  
Vol 93 (06) ◽  
pp. 1176-1184 ◽  
Author(s):  
Ulrike Möller ◽  
Stephan Herzig ◽  
Trine Fink ◽  
Vladimir Zachar ◽  
Peter Ebbesen ◽  
...  
Keyword(s):  
Growth Factor ◽  
Hepg2 Cells ◽  
Hypoxia Inducible Factor ◽  
Plasminogen Activator Inhibitor ◽  
Dominant Negative ◽  
Plasminogen Activator Inhibitor 1 ◽  
Protein Levels ◽  
Hypoxia Inducible Factor 1 ◽  
Activator Inhibitor ◽  
Pai 1

SummaryInsulin-like growth factor 1 (IGF-1) and plasminogen activator inhibitor-1 (PAI-1) appear to play a crucial role in a number of processes associated with growth and tissue remodelling. IGF-1 was shown to enhance PAI-1 expression in primary hepatocytes and HepG2 hepatoma cells, but the molecular mechanisms underlying this effect have not been fully elucidated. In this study, we investigated the transcriptional mechanism and the signaling pathway by which IGF-1 mediates induction of PAI-1 expression in HepG2 cells. By using human PAI-1 promoter reporter gene assays we found that mutation of the hypoxia responsive element (HRE), which could bind hypoxia-inducible factor-1 (HIF-1), nearly abolished the induction by IGF-1. We found that IGF-1-induced up-regulation of PAI-1 expression was associated with activation of HIF-1α. Furthermore, IGF-1 enhanced HIF-1α protein levels and HIF-1 DNA-binding to each HRE, E4 and E5 as shown by EMSA. Mutation of the E-boxes, E4 and E5, did not affect the IGF-1-dependent induction of PAI-1 promoter constructs under normoxia but abolished the effect of IGF-1 under hypoxia. Inhibition of either the PI3K by LY294002 or ERK1/2 by U0126 reduced HIF-1α protein levels while both inhibitors together completely abolished the IGF-1 effect on HIF-1α. Remarkably, transfection of HepG2 cells with vectors expressing a dominant-negative PDK1 or the PKB inhibitor, TRB3, did not influence while dominant-negative Raf inhibited the IGF-1 effect on HIF-1α. Thus, IGF-1 activates human PAI-1 gene expression through activation of the PI3-kinase and ERK1/2 via HIF-1α.

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