Upregulation of hypoxia-inducible factor (HIF)-1α and HIF-2α mRNA levels in dragonet Callionymus valenciennei exposed to environmental hypoxia in Tokyo Bay

Efforts to assess the ecological impacts of the marked increase in coastal hypoxia worldwide have been hampered by a lack of biomarkers of hypoxia exposure in marine benthic organisms. Here, we show that hypoxia-inducible factor-1α (HIF-1α) transcript levels in the heart and cerebral ganglion of mantis shrimp ( Oratosquilla oratoria ) collected from hypoxic sites in Tokyo Bay are elevated several-fold over those in shrimp collected from normoxic sites. Upregulation of HIF-1α mRNA levels in the heart after exposure to sub-lethal hypoxia was confirmed in controlled laboratory experiments. HIF-1α transcript levels were increased at approximately threefold after 7 and 14 days of hypoxia exposure and declined to control levels within 24 h of restoration to normoxic conditions. The results provide the first evidence for upregulation of HIF-1α transcript levels in two hypoxia-sensitive organs, heart and cerebral ganglion, in a marine invertebrate exposed to environmental hypoxia. These results suggest that upregulation of HIF-1α transcript levels is an important component in adaptation of mantis shrimp to chronic hypoxia and is a potentially useful biomarker of environmental hypoxia exposure.

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Transmembrane prolyl 4-hydroxylase is a fourth prolyl 4-hydroxylase regulating EPO production and erythropoiesis

Blood ◽

10.1182/blood-2012-07-441824 ◽

2012 ◽

Vol 120 (16) ◽

pp. 3336-3344 ◽

Cited By ~ 36

Author(s):

Anu Laitala ◽

Ellinoora Aro ◽

Gail Walkinshaw ◽

Joni M. Mäki ◽

Maarit Rossi ◽

...

Keyword(s):

Cultured Cells ◽

Mrna Level ◽

Hypoxia Inducible Factor ◽

Mrna Levels ◽

Wild Type ◽

Α Subunit ◽

Hepcidin Expression ◽

In The Wild ◽

Hepcidin Mrna

AbstractAn endoplasmic reticulum transmembrane prolyl 4-hydroxylase (P4H-TM) is able to hydroxylate the α subunit of the hypoxia-inducible factor (HIF) in vitro and in cultured cells, but nothing is known about its roles in mammalian erythropoiesis. We studied such roles here by administering a HIF-P4H inhibitor, FG-4497, to P4h-tm−/− mice. This caused larger increases in serum Epo concentration and kidney but not liver Hif-1α and Hif-2α protein and Epo mRNA levels than in wild-type mice, while the liver Hepcidin mRNA level was lower in the P4h-tm−/− mice than in the wild-type. Similar, but not identical, differences were also seen between FG-4497–treated Hif-p4h-2 hypomorphic (Hif-p4h-2gt/gt) and Hif-p4h-3−/− mice versus wild-type mice. FG-4497 administration increased hemoglobin and hematocrit values similarly in the P4h-tm−/− and wild-type mice, but caused higher increases in both values in the Hif-p4h-2gt/gt mice and in hematocrit value in the Hif-p4h-3−/− mice than in the wild-type. Hif-p4h-2gt/gt/P4h-tm−/− double gene-modified mice nevertheless had increased hemoglobin and hematocrit values without any FG-4497 administration, although no such abnormalities were seen in the Hif-p4h-2gt/gt or P4h-tm−/− mice. Our data thus indicate that P4H-TM plays a role in the regulation of EPO production, hepcidin expression, and erythropoiesis.

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A possible role for hypoxia-induced apelin expression in enteric cell proliferation

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00083.2008 ◽

2008 ◽

Vol 294 (6) ◽

pp. R1832-R1839 ◽

Cited By ~ 32

Author(s):

Song Han ◽

Guiyun Wang ◽

Xiang Qi ◽

Heung M. Lee ◽

Ella W. Englander ◽

...

Keyword(s):

Cell Proliferation ◽

Epithelial Cell ◽

Intestinal Inflammation ◽

Acute Hypoxia ◽

Hypoxia Inducible Factor ◽

Mrna Levels ◽

Epithelial Cell Proliferation ◽

Gi Tract ◽

Rat Pups

Apelin is the endogenous ligand for the APJ receptor, and apelin and APJ are expressed in the gastrointestinal (GI) tract. Intestinal inflammation increases intestinal hypoxia-inducible factor (HIF) and apelin expression. Hypoxia and inflammation are closely linked cellular insults. The purpose of these studies was to investigate the influence of hypoxia on enteric apelin expression. Exposure of rat pups to acute hypoxia increased hepatic, stomach-duodenal, and colonic apelin mRNA levels 10-, 2-, and 2-fold, respectively ( P < 0.05 vs. controls). Hypoxia also increased colonic APJ mRNA levels, and apelin treatment during hypoxia exposure enhanced colonic APJ mRNA levels further. In vitro hypoxia also increased apelin and APJ mRNA levels. The hypoxia-induced elevation in apelin expression is most likely mediated by HIF, since HIF-activated apelin transcriptional activity is dependent on an intact, putative HIF binding site in the rat apelin promoter. Acute exposure of rat pups to hypoxia lowered gastric and colonic epithelial cell proliferation; hypoxia in combination with apelin treatment increased epithelial proliferation by 50%. In vitro apelin treatment of enteric cells exposed to hypoxia increased cell proliferation. Apelin treatment during normoxia was ineffective. Our studies imply that the elevation in apelin expression during hypoxia and inflammation in the GI tract functions in part to stimulate epithelial cell proliferation.

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Hypoxia-induced pulmonary endothelin-1 expression is unaltered by nitric oxide

Journal of Applied Physiology ◽

10.1152/japplphysiol.00829.2001 ◽

2002 ◽

Vol 92 (3) ◽

pp. 1152-1158 ◽

Cited By ~ 15

Author(s):

Scott Earley ◽

Leif D. Nelin ◽

Louis G. Chicoine ◽

Benjimen R. Walker

Keyword(s):

Nitric Oxide ◽

Endothelial Cells ◽

Promoter Activity ◽

Umbilical Vein ◽

Hypoxia Inducible Factor ◽

Hypoxic Exposure ◽

Mrna Levels ◽

Protective Effects ◽

No Donor ◽

Umbilical Vein Endothelial Cells

Nitric oxide (NO) attenuates hypoxia-induced endothelin (ET)-1 expression in cultured umbilical vein endothelial cells. We hypothesized that NO similarly attenuates hypoxia-induced increases in ET-1 expression in the lungs of intact animals and reasoned that potentially reduced ET-1 levels may contribute to the protective effects of NO against the development of pulmonary hypertension during chronic hypoxia. As expected, hypoxic exposure (24 h, 10% O2) increased rat lung ET-1 peptide and prepro-ET-1 mRNA levels. Contrary to our hypothesis, inhaled NO (iNO) did not attenuate hypoxia-induced increases in pulmonary ET-1 peptide or prepro-ET-1 mRNA levels. Because of this surprising finding, we also examined the effects of NO on hypoxia-induced increases in ET peptide levels in cultured cell experiments. Consistent with the results of iNO experiments, administration of the NO donor S-nitroso- N-acetyl-penicillamine to cultured bovine pulmonary endothelial cells did not attenuate increases in ET peptide levels resulting from hypoxic (24 h, 3% O2) exposure. In additional experiments, we examined the effects of NO on the activity of a cloned ET-1 promoter fragment containing a functional hypoxia inducible factor-1 binding site in reporter gene experiments. Whereas moderate hypoxia (24 h, 3% O2) had no effect on ET-1 promoter activity, activity was increased by severe hypoxic (24 h, 0.5% O2) exposure. ET-1 promoter activity after S-nitroso- N-acetyl-penicillamine administration during severe hypoxia was greater than that in normoxic controls, although activity was reduced compared with that in hypoxic controls. These findings suggest that hypoxia-induced pulmonary ET-1 expression is unaffected by NO.

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The Hypoxia-Inducible Factor 1/NOR-1 Axis Regulates the Survival Response of Endothelial Cells to Hypoxia

Molecular and Cellular Biology ◽

10.1128/mcb.00945-09 ◽

2009 ◽

Vol 29 (21) ◽

pp. 5828-5842 ◽

Cited By ~ 42

Author(s):

Lluis Martorell ◽

Maurizio Gentile ◽

Jordi Rius ◽

Cristina Rodríguez ◽

Javier Crespo ◽

...

Keyword(s):

Endothelial Cells ◽

Transcriptional Activation ◽

Hypoxia Inducible Factor ◽

Orphan Receptor ◽

Vegf Receptor ◽

Mrna Levels ◽

Dependent Manner ◽

Small Interfering Rnas ◽

Hypoxia Inducible Factor 1 ◽

Apoptosis Protein

ABSTRACT Hypoxia induces apoptosis but also triggers adaptive mechanisms to ensure cell survival. Here we show that the prosurvival effects of hypoxia-inducible factor 1 (HIF-1) in endothelial cells are mediated by neuron-derived orphan receptor 1 (NOR-1). The overexpression of NOR-1 decreased the rate of endothelial cells undergoing apoptosis in cultures exposed to hypoxia, while the inhibition of NOR-1 increased cell apoptosis. Hypoxia upregulated NOR-1 mRNA levels in a time- and dose-dependent manner. Blocking antibodies against VEGF or SU5614 (a VEGF receptor 2 inhibitor) did not prevent hypoxia-induced NOR-1 expression, suggesting that NOR-1 is not induced by the autocrine secretion of VEGF in response to hypoxia. The reduction of HIF-1α protein levels by small interfering RNAs, or by inhibitors of the phosphatidylinositol-3 kinase (PI3K)/Akt pathway or mTOR, significantly counteracted hypoxia-induced NOR-1 upregulation. Intracellular Ca2+ was involved in hypoxia-induced PI3K/Akt activation and in the downstream NOR-1 upregulation. A hypoxia response element mediated the transcriptional activation of NOR-1 induced by hypoxia as we show by transient transfection and chromatin immunoprecipitation assays. Finally, the attenuation of NOR-1 expression reduced both basal and hypoxia-induced cIAP2 (cellular inhibitor of apoptosis protein 2) mRNA levels, while NOR-1 overexpression upregulated cIAP2. Therefore, NOR-1 is a downstream effector of HIF-1 signaling involved in the survival response of endothelial cells to hypoxia.

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Redox regulation of HIF-1α levels and HO-1 expression in renal medullary interstitial cells

AJP Renal Physiology ◽

10.1152/ajprenal.00017.2002 ◽

2003 ◽

Vol 284 (6) ◽

pp. F1207-F1215 ◽

Cited By ~ 51

Author(s):

Zhi-Zhang Yang ◽

Andrew Y. Zhang ◽

Fu-Xian Yi ◽

Pin-Lan Li ◽

Ai-Ping Zou

Keyword(s):

Blot Analysis ◽

Posttranscriptional Regulation ◽

Redox Regulation ◽

Hypoxia Inducible Factor ◽

Proteasome Inhibition ◽

Interstitial Cells ◽

Heme Oxygenase 1 ◽

Oh Radicals ◽

Mrna Levels ◽

Renal Cells

The present study hypothesized that superoxide (O[Formula: see text]·) importantly contributes to the regulation of hypoxia-inducible factor (HIF)-1α expression at posttranscriptional levels in renal medullary interstitial cells (RMICs) of rats. By Western blot analysis, it was found that incubation of RMICs with O[Formula: see text]· generators xanthine/xanthine oxidase and menadione significantly inhibited the hypoxia- or CoCl2-induced increase in HIF-1α levels and completely blocked the increase in HIF-1α levels induced by ubiquitin-proteasome inhibition with CBZ-LLL in the nuclear extracts from these cells. Under normoxic conditions, a cell-permeable O[Formula: see text]· dismutase (SOD) mimetic, 4-hydroxyl-tetramethylpiperidin-oxyl (TEMPOL) and PEG-SOD, significantly increased HIF-1α levels in RMICs. Two mechanistically different inhibitors of NAD(P)H oxidase, diphenyleneiodonium and apocynin, were also found to increase HIF-1α levels in these renal cells. Moreover, introduction of an anti-sense oligodeoxynucleotide specific to NAD(P)H oxidase subunit, p22phox, into RMICs markedly increased HIF-1α levels. In contrast, the OH· scavenger tetramethylthiourea had no effect on the accumulation of HIF-1α in these renal cells. By Northern blot analysis, scavenging or dismutation of O[Formula: see text]· by TEMPOL and PEG-SOD was found to increase the mRNA levels of an HIF-1α-targeted gene, heme oxygenase-1. These results indicate that increased intracellular O[Formula: see text]· levels induce HIF-1α degradation independently of H2O2and OH· radicals in RMICs. NAD(P)H oxidase activity may importantly contribute to this posttranscriptional regulation of HIF-1α in these cells under physiological conditions.

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Inhibitor of DNA Binding 1 Is Induced during Kidney Ischemia-Reperfusion and Is Critical for the Induction of Hypoxia-Inducible Factor-1α

BioMed Research International ◽

10.1155/2016/4634386 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 8

Author(s):

Dan Wen ◽

Yan-Fang Zou ◽

Yao-Hui Gao ◽

Qian Zhao ◽

Yin-Yin Xie ◽

...

Keyword(s):

Dna Binding ◽

Ischemia Reperfusion ◽

Hypoxia Inducible Factor ◽

Kidney Injury ◽

Mrna Levels ◽

Hypoxia Inducible Factor 1 ◽

Renal Tubular ◽

Inhibitor Of Dna Binding

In this study, rat models of acute kidney injury (AKI) induced by renal ischemia-reperfusion (I/R) and HK-2 cell models of hypoxia-reoxygenation (H/R) were established to investigate the expression of inhibitor of DNA binding 1 (ID1) in AKI, and the regulation relationship between ID1 and hypoxia-inducible factor 1 alpha (HIF-1α). Through western blot, quantitative real-time PCR, immunohistochemistry, and other experiment methods, the induction of ID1 after renal I/R in vivo was observed, which was expressed mainly in renal tubular epithelial cells (TECs). ID1 expression was upregulated in in vitro H/R models at both the protein and mRNA levels. Via RNAi, it was found that ID1 induction was inhibited with silencing of HIF-1α. Moreover, the suppression of ID1 mRNA expression could lead to decreased expression and transcription of HIF-1αduring hypoxia and reoxygenation. In addition, it was demonstrated that both ID1 and HIF-1αcan regulate the transcription of twist. This study demonstrated that ID1 is induced in renal TECs during I/R and can regulate the transcription and expression of HIF-1α.

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Hypoxia Inducible Factor-1α Is over Expressed in CLL B Cells Because of an Impaired Proteasome Pathway Associated with Defective Interaction with von Hippel-Landau Protein.

Blood ◽

10.1182/blood.v106.11.2115.2115 ◽

2005 ◽

Vol 106 (11) ◽

pp. 2115-2115 ◽

Cited By ~ 1

Author(s):

Yean K. Lee ◽

Ann K. Strege ◽

Nancy D. Bone ◽

Linda E. Wellik ◽

D. A. Chan ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Target Genes ◽

Hypoxia Inducible Factor ◽

Nuclear Extract ◽

Degradation Pathway ◽

Mrna Levels ◽

Apoptosis Resistance ◽

Vegf Mrna ◽

Prolyl Hydroxylases

Abstract We have found that CLL B cells spontaneously secrete vascular endothelial growth factor (VEGF) and that a VEGF autocrine pathway can induce apoptosis resistance in these cells. Recently, we also found that hypoxia-inducible factor-1 alpha (HIF-1α) is highly expressed in CLL B cells. Since this protein is a potent transcription factor for the induction of VEGF, we were interested in further definition of HIF-1α regulation and its function in CLL B cells. CLL blood B cells overexpress HIF-1α protein but not mRNA for HIF-1α compared to normal blood and splenic B cells. Immunohistochemistry (IHC) showed that circulating blood CLL B cells and a subset of CLL marrow cells uniformly express HIF. Hypoxic conditions (i.e., 1% O2) did not increase the protein levels of HIF-1α nor mRNA for HIF-1α in CLL B cells, indicating that the high HIF-1α protein level is due to post-translation modification. Blockade of signaling pathways known to increase HIF-1α levels also did not alter the high levels of HIF-1α in CLL B cells. IHC and nuclear extraction assay demonstrated that HIF-1α was predominantly located in the CLL B cell nucleus. In addition, the nuclear extract when immunoprecipitated for HIF-1α was shown to be complexed with the co-activator p300, indicating that HIF-1α is transcriptionally active. Co-immunoprecipitation assay showed that HIF-1α from CLL B cells does not associate and form a complex with von Hippel-Landau protein tumor suppressor (pVHL), indicating that the proteasome dependent degradation pathway for HIF-1α protein in CLL B cells is dysfunctional. Using immunoblot or IHC methods, we were unable to detect pVHL protein in CLL B cells; however, we were able to use immunoprecipitation of CLL B cell lysates to demonstrate there is pVHL in CLL B cells. Prolyl hydroxylases (PHD 1, 2, and 3) are negative regulators for HIF-1α via hydroxylation of amino acid prolines in the oxygen degradation domain (ODD) which permits interaction with pVHL. RT-PCR results revealed that there is a subset of CLL patients who had ≥ 50% reduction of PHD 1 and 3 mRNA levels. However using a hydroxylation specific polyclonal antibody we found that HIF-1α from CLL B cells is indeed hydroxylated. Finally, silencing of HIF-1α by RNA interference in CLL B cells was associated with a selective decrease in VEGF mRNA levels but not VEGF-R1, Mcl-1 and prolyl hydroxylases (PHD 1–3) other downstream target genes of HIF-1α. These data show that the high endogenous HIF-1α levels in CLL B cells are due to a defect in HIF-1α degradation via the proteosomal pathway. We believe that this abnormality is linked to the autocrine VEGF pathway in CLL B cells and ultimately results in increases in their apoptotic resistance. Inhibition of HIF-1α levels may be of therapeutic benefit to CLL patients.

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Strong iron demand during hypoxia-induced erythropoiesis is associated with down-regulation of iron-related proteins and myoglobin in human skeletal muscle

Blood ◽

10.1182/blood-2006-08-040006 ◽

2007 ◽

Vol 109 (11) ◽

pp. 4724-4731 ◽

Cited By ~ 79

Author(s):

Paul Robach ◽

Gaetano Cairo ◽

Cecilia Gelfi ◽

Francesca Bernuzzi ◽

Henriette Pilegaard ◽

...

Keyword(s):

Skeletal Muscle ◽

Iron Content ◽

Iron Homeostasis ◽

Iron Acquisition ◽

Hypoxia Inducible Factor ◽

Hemoglobin Concentration ◽

Oxygen Binding ◽

Mrna Levels ◽

Iron Regulatory Proteins ◽

Related Proteins

Abstract Iron is essential for oxygen transport because it is incorporated in the heme of the oxygen-binding proteins hemoglobin and myoglobin. An interaction between iron homeostasis and oxygen regulation is further suggested during hypoxia, in which hemoglobin and myoglobin syntheses have been reported to increase. This study gives new insights into the changes in iron content and iron-oxygen interactions during enhanced erythropoiesis by simultaneously analyzing blood and muscle samples in humans exposed to 7 to 9 days of high altitude hypoxia (HA). HA up-regulates iron acquisition by erythroid cells, mobilizes body iron, and increases hemoglobin concentration. However, contrary to our hypothesis that muscle iron proteins and myoglobin would also be up-regulated during HA, this study shows that HA lowers myoglobin expression by 35% and down-regulates iron-related proteins in skeletal muscle, as evidenced by decreases in L-ferritin (43%), transferrin receptor (TfR; 50%), and total iron content (37%). This parallel decrease in L-ferritin and TfR in HA occurs independently of increased hypoxia-inducible factor 1 (HIF-1) mRNA levels and unchanged binding activity of iron regulatory proteins, but concurrently with increased ferroportin mRNA levels, suggesting enhanced iron export. Thus, in HA, the elevated iron requirement associated with enhanced erythropoiesis presumably elicits iron mobilization and myoglobin down-modulation, suggesting an altered muscle oxygen homeostasis.

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Molecular, functional, and gene expression analysis of zebrafish hypoxia-inducible factor-3α

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00340.2012 ◽

2012 ◽

Vol 303 (11) ◽

pp. R1165-R1174 ◽

Cited By ~ 30

Author(s):

Peng Zhang ◽

Ling Lu ◽

Qing Yao ◽

Yun Li ◽

Jianfeng Zhou ◽

...

Keyword(s):

Gene Expression ◽

Fluorescent Protein ◽

Cultured Cells ◽

Hypoxia Inducible Factor ◽

Model Organism ◽

Mrna Levels ◽

Dependent Manner ◽

Specific Expression ◽

Physiological Regulation ◽

Functional Conservation

Hypoxia-inducible factors 1–3 (HIF1–3) are transcription factors that regulate gene expression in response to hypoxia. Compared with our extensive understanding of HIF-1 and HIF-2, our knowledge of HIF-3 is limited. In this study, we characterized the zebrafish hif-3α gene and determined its temporal and spatial expression, physiological regulation, and biological activity. We show that the chromosomal location, gene structure, and protein structure of zebrafish hif-3α are similar to its mammalian orthologs. When tagged with enhanced green fluorescent protein and transfected into cultured cells, zebrafish Hif-3α was localized in the nucleus and stimulated reporter gene expression in a hypoxia response element-dependent manner. During early development, hif-3α mRNA was detected in all tissues with higher levels in the head. This expression pattern became more apparent in larvae at the 72, 96, and 120 hours post fertilization stages. In the adult stage, hif-3α mRNA was detected in all examined tissues with the highest levels in the ovary. Hypoxia treatment increased Hif-3α protein levels in both embryos and adults. Hypoxia also increased hif-3α mRNA expression levels, and this regulation was tissue-specific. Expression of a stabilized form of Hif-1α in zebrafish embryos increased the expression of igfbp-1a, a Hif-1 target gene, whereas it did not change hif-3α mRNA levels, suggesting that hif-3α is not a Hif-1α target. These results provide new information about the structural and functional conservation, spatial and temporal expression, and physiological regulation of hif-3α in a teleost model organism.

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