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D'Ignazio L, Rocha S. Hypoxia Induced NF-κB. Cells 2016; 5:cells5010010. [PMID: 27005664 PMCID: PMC4810095 DOI: 10.3390/cells5010010] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 12/24/2022] Open
Abstract
As Nuclear Factor-κB (NF-κB) is a major transcription factor responding to cellular stress, it is perhaps not surprising that is activated by hypoxia, or decreased oxygen availability. However, how NF-κB becomes activated in hypoxia is still not completely understood. Several mechanisms have been proposed and this review will focus on the main findings highlighting the molecules that have been identified in the process of hypoxia induced NF-κB. In addition, we will discuss the role of NF-κB in the control of the cellular response to hypoxia.
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Affiliation(s)
- Laura D'Ignazio
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow street, Dundee DD1 5EH, UK.
| | - Sonia Rocha
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow street, Dundee DD1 5EH, UK.
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Singh M, Devi U, Roy S, Gupta PS, Saraf SA, Kaithwas G. Prolyl hydroxylase mediated inhibition of fatty acid synthase to combat tumor growth in mammary gland carcinoma. Breast Cancer 2016; 23:820-829. [PMID: 26951539 DOI: 10.1007/s12282-016-0683-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/24/2016] [Indexed: 12/12/2022]
Abstract
Cancer is a group of cells which grow in an uncontrolled manner and invades to the adjacent organs to form malignant tumors. Tumor hypoxia results due to contrast between the cellular oxygen expenditure and oxygen supply to the cells. Hypoxia inducible factor (HIF) is a heterodimeric transcription factor encompass of oxygen sensitive α subunit and constitutively expressed β subunit both of which are basic helix-loop-helix protein. The stability of HIF is primarily regulated by post translational prolyl hydroxylation, catalyzed by prolyl hydroxylase 2 (Phd-2). Phd-2 is a group of enzymes that acts as an oxygen sensor. Cancer cells have altered metabolism as they fulfil their energy needs through glycolysis and lipid biogenesis. HIF-1α is known to upregulate glycolysis by activating the transcription of enzymes on the glycolytic pathway and through lipogenesis. Cancer cells have over expressed fatty acid synthase owing to altered glycolytic pathway. Considering the above, it is hypothesized that chemical activation of Phd-2 can curtail down HIF-1α and subsequently fatty acid synthase expression.
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Affiliation(s)
- Manjari Singh
- Department of Pharmaceutical Sciences, School of Biosciences and Biotechnology, Babasaheb Bhimrao Ambedkar University (A Central University), Vidya Vihar, Raebareli Road, Lucknow, 226025, India
| | - Uma Devi
- Department of Pharmaceutical Sciences, Faculty of Health Medical Sciences Indigenous and Alternative Medicine, SHIATS-Deemed to be University, Naini, Allahabad, Uttar Pradesh, India
| | - Subhadeep Roy
- Department of Pharmaceutical Sciences, School of Biosciences and Biotechnology, Babasaheb Bhimrao Ambedkar University (A Central University), Vidya Vihar, Raebareli Road, Lucknow, 226025, India
| | - Pushpraj S Gupta
- Department of Pharmaceutical Sciences, Faculty of Health Medical Sciences Indigenous and Alternative Medicine, SHIATS-Deemed to be University, Naini, Allahabad, Uttar Pradesh, India
| | - Shubhini A Saraf
- Department of Pharmaceutical Sciences, School of Biosciences and Biotechnology, Babasaheb Bhimrao Ambedkar University (A Central University), Vidya Vihar, Raebareli Road, Lucknow, 226025, India
| | - Gaurav Kaithwas
- Department of Pharmaceutical Sciences, School of Biosciences and Biotechnology, Babasaheb Bhimrao Ambedkar University (A Central University), Vidya Vihar, Raebareli Road, Lucknow, 226025, India.
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Eleftheriadis T, Pissas G, Antoniadi G, Liakopoulos V, Stefanidis I. Proteasome or immunoproteasome inhibitors cause apoptosis in human renal tubular epithelial cells under normoxic and hypoxic conditions. Int Urol Nephrol 2016; 48:907-15. [DOI: 10.1007/s11255-016-1247-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/13/2016] [Indexed: 11/28/2022]
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Quaegebeur A, Segura I, Schmieder R, Verdegem D, Decimo I, Bifari F, Dresselaers T, Eelen G, Ghosh D, Davidson SM, Schoors S, Broekaert D, Cruys B, Govaerts K, De Legher C, Bouché A, Schoonjans L, Ramer MS, Hung G, Bossaert G, Cleveland DW, Himmelreich U, Voets T, Lemmens R, Bennett CF, Robberecht W, De Bock K, Dewerchin M, Ghesquière B, Fendt SM, Carmeliet P. Deletion or Inhibition of the Oxygen Sensor PHD1 Protects against Ischemic Stroke via Reprogramming of Neuronal Metabolism. Cell Metab 2016; 23:280-91. [PMID: 26774962 PMCID: PMC4880550 DOI: 10.1016/j.cmet.2015.12.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 10/30/2015] [Accepted: 12/11/2015] [Indexed: 01/08/2023]
Abstract
The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network. Instead, PHD1(-/-) neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1(-/-) neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose away from glycolysis. As a result, PHD1(-/-) neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke.
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Affiliation(s)
- Annelies Quaegebeur
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Inmaculada Segura
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Roberta Schmieder
- Laboratory of Cellular Metabolism and Metabolic Regulation, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Cellular Metabolism and Metabolic Regulation, Vesalius Research Center, VIB, Leuven, Belgium
| | - Dries Verdegem
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium; Metabolomics Expertise Center, Vesalius Research Center, VIB, Leuven, Belgium
| | - Ilaria Decimo
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Francesco Bifari
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Tom Dresselaers
- Biomedical MRI/Mosaic, Department of Imaging and Pathology, University of Leuven, Leuven, Belgium
| | - Guy Eelen
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Debapriva Ghosh
- Laboratory of Ion Channel Research and TRP channel research platform Leuven, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Shawn M Davidson
- Koch Institute for Integrative Cancer Research at Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sandra Schoors
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Dorien Broekaert
- Laboratory of Cellular Metabolism and Metabolic Regulation, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Cellular Metabolism and Metabolic Regulation, Vesalius Research Center, VIB, Leuven, Belgium
| | - Bert Cruys
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Kristof Govaerts
- Biomedical MRI/Mosaic, Department of Imaging and Pathology, University of Leuven, Leuven, Belgium
| | - Carla De Legher
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Ann Bouché
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Luc Schoonjans
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Matt S Ramer
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium; International Collaboration on Repair Discoveries, the University of British Columbia, Vancouver, Canada
| | - Gene Hung
- Isis Pharmaceuticals, Carlsbad, CA 92008, USA
| | - Goele Bossaert
- Leuven Statistics Research Centre (LStat), University of Leuven, Leuven, Belgium
| | - Don W Cleveland
- Ludwig Institute for Cancer Research, Department of Medicine and Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - Uwe Himmelreich
- Biomedical MRI/Mosaic, Department of Imaging and Pathology, University of Leuven, Leuven, Belgium
| | - Thomas Voets
- Laboratory of Ion Channel Research and TRP channel research platform Leuven, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Robin Lemmens
- Laboratory of Neurobiology, Vesalius Research Center, VIB, Leuven, Belgium; Experimental Neurology (Department of Neurosciences) and Leuven Research Institute for Neuroscience and Disease (LIND), University of Leuven, Leuven, Belgium; Neurology, University Hospitals Leuven, Leuven, Belgium
| | | | - Wim Robberecht
- Laboratory of Neurobiology, Vesalius Research Center, VIB, Leuven, Belgium; Experimental Neurology (Department of Neurosciences) and Leuven Research Institute for Neuroscience and Disease (LIND), University of Leuven, Leuven, Belgium; Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Katrien De Bock
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Mieke Dewerchin
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
| | - Bart Ghesquière
- Metabolomics Expertise Center, Vesalius Research Center, VIB, Leuven, Belgium
| | - Sarah-Maria Fendt
- Laboratory of Cellular Metabolism and Metabolic Regulation, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Cellular Metabolism and Metabolic Regulation, Vesalius Research Center, VIB, Leuven, Belgium
| | - Peter Carmeliet
- Laboratory of Angiogenesis and Neurovascular link, Department of Oncology, University of Leuven, Leuven, Belgium; Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium.
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Schindler K, Bondeva T, Schindler C, Claus RA, Franke S, Wolf G. Preconditioned suppression of prolyl-hydroxylases attenuates renal injury but increases mortality in septic murine models. Nephrol Dial Transplant 2016; 31:1100-13. [DOI: 10.1093/ndt/gfv442] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/05/2015] [Indexed: 01/04/2023] Open
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Pharmacological targeting of the HIF hydroxylases--A new field in medicine development. Mol Aspects Med 2016; 47-48:54-75. [PMID: 26791432 DOI: 10.1016/j.mam.2016.01.001] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/11/2015] [Accepted: 01/04/2016] [Indexed: 12/13/2022]
Abstract
In human cells oxygen levels are 'sensed' by a set of ferrous iron and 2-oxoglutarate dependent dioxygenases. These enzymes regulate a broad range of cellular and systemic responses to hypoxia by catalysing the post-translational hydroxylation of specific residues in the alpha subunits of hypoxia inducible factor (HIF) transcriptional complexes. The HIF hydroxylases are now the subject of pharmaceutical targeting by small molecule inhibitors that aim to activate or augment the endogenous HIF transcriptional response for the treatment of anaemia and other hypoxic human diseases. Here we consider the rationale for this therapeutic strategy from the biochemical, biological and medical perspectives. We outline structural and mechanistic considerations that are relevant to the design of HIF hydroxylase inhibitors, including likely determinants of specificity, and review published reports on their activity in pre-clinical models and clinical trials.
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Barakat R, Redzic Z. The Role of Activated Microglia and Resident Macrophages in the Neurovascular Unit during Cerebral Ischemia: Is the Jury Still Out? Med Princ Pract 2016; 25 Suppl 1:3-14. [PMID: 26303836 PMCID: PMC5588523 DOI: 10.1159/000435858] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 06/10/2015] [Indexed: 12/13/2022] Open
Abstract
Paracrine signaling in the neurovascular unit (NVU) is aimed to adjust the supply of oxygen and nutrients to metabolic demands of the brain in a feed-forward manner. Cerebral ischemia (CI) severely disrupts this homeostatic mechanism and also causes activation of microglia and resident macrophages in the brain. Contradictory data exist on the time pattern of microglial activation and polarization during CI, on molecular mechanisms that trigger them and on effects of microglia-derived cytokines on brain cells. It appears that conditions that occur during transient ischemia or in the penumbra of focal ischemia in vivo or equivalent conditions in vitro trigger polarization of resting microglia/macrophages into the M2 phenotype, which mainly exerts anti-inflammatory and protective effects in the brain, while prolonged ischemia with abundant necrosis promotes microglial polarization into the M1 phenotype. During the later stages of recovery, microglia that polarized initially into the M2 phenotype can shift into the M1 phenotype. Thus, it appears that cells with both phenotypes are present in the affected area, but their relative amount changes in time and probably depends on the proximity to the ischemic core. It was assumed that cells with the M1 phenotype exert detrimental effects on neurons and contribute to the blood-brain barrier opening. Several M1 phenotype-specific cytokines exert protective effects on astrocytes, which could be important for reactive gliosis occurring after ischemia. Thus, whether or not suppression of microglial activity after CI is beneficial for neurological outcome still remains unclear and current evidence suggests that no simple answer could be given to this question.
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Affiliation(s)
| | - Zoran Redzic
- *Dr. Zoran Redzic, Department of Physiology, Faculty of Medicine, Kuwait University, PO Box 24923, Safat 13110 (Kuwait), E-Mail
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Affiliation(s)
- P. B. Persson
- Institute of Vegetative Physiology; Charité-Universitaetsmedizin Berlin; Berlin Germany
| | - M. Mueller
- Institute of Vegetative Physiology; Charité-Universitaetsmedizin Berlin; Berlin Germany
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Recent Advances in Developing Inhibitors for Hypoxia-Inducible Factor Prolyl Hydroxylases and Their Therapeutic Implications. Molecules 2015; 20:20551-68. [PMID: 26610437 PMCID: PMC6332328 DOI: 10.3390/molecules201119717] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 11/10/2015] [Accepted: 11/11/2015] [Indexed: 12/13/2022] Open
Abstract
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.
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Zhdanov AV, Okkelman IA, Collins FW, Melgar S, Papkovsky DB. A novel effect of DMOG on cell metabolism: direct inhibition of mitochondrial function precedes HIF target gene expression. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1254-66. [DOI: 10.1016/j.bbabio.2015.06.016] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 06/11/2015] [Accepted: 06/30/2015] [Indexed: 12/17/2022]
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Affiliation(s)
- S. Reuter
- Klinik für Innere Medizin III; AG Experimentelle Nephrologie; Universitätsklinikum Jena; Jena Germany
| | - R. Mrowka
- Klinik für Innere Medizin III; AG Experimentelle Nephrologie; Universitätsklinikum Jena; Jena Germany
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Ye ZL, Huang Y, Li LF, Zhu HL, Gao HX, Liu H, Lv SQ, Xu ZH, Zheng LN, Liu T, Zhang JL, Jin HJ, Qian QJ. Argonaute 2 promotes angiogenesis via the PTEN/VEGF signaling pathway in human hepatocellular carcinoma. Acta Pharmacol Sin 2015; 36:1237-45. [PMID: 25937637 DOI: 10.1038/aps.2015.18] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Accepted: 03/06/2015] [Indexed: 12/14/2022] Open
Abstract
AIM Argonaute2 (AGO2) protein is the active part of RNA-induced silencing complex, cleaving the target mRNA strand complementary to their bound siRNA. An increasing number of miRNAs has been identified as essential to angiogenesis of hepatocellular carcinoma (HCC). In this study we investigated how AGO2 affected HCC angiogenesis. METHODS Human HCC cell lines HepG2, Hep3B, Huh7, SMMC-7721, Bel-7404, MHCC97-H and LM-3, and human umbilical vein endothelial cells (HUVEC) were tested. The expression of AGO2 in HCC cells was knocked down with siRNA and restored using recombinant adenovirus expressing Ago2. The levels of relevant mRNAs and proteins were examined using RT-PCR, Western blot and EILSA. Nude mice were implanted with Huh7 or SMMC-7721 cells, and tumor volumes were measured. After the mice were euthanized, the xenograft tumors were used for immunohistological analysis. RESULTS In 6 HCC cell lines, AGO2 protein expression was significantly correlated with VEGF expression (r=+0.79), and with VEGF secretion (r=+0.852). Knockdown of Ago2 in Huh7 cells and SMMC-7721 cells substantially decreased VEGF expression, whereas the restoration of AGO2 reversed both VEGF expression and secretion. Furthermore, knockdown of Ago2 significantly up-regulated the expression of PTEN (a tumor suppressor involved in the inhibition of HCC angiogenesis), and vice versa. Moreover, the specific PTEN inhibitor bisperoxovanadate (7, 14, 28 nmol/L) dose-dependently restored the expression of VEGF and the capacity of HCC cells to induce HUVECs to form capillary tubule structures. In the xenograft nude mice, knockdown of Ago2 markedly suppressed the tumor growth and decreased PTEN expression and CD31-positive microvascular in the xenograft tumors. CONCLUSION A direct relationship exists between the miRNA processing machinery AGO2 and HCC angiogenesis that is mediated by the AGO2/PTEN/VEGF signaling pathway. The results suggest the high value of Ago2 knockdown in anti-angiogenesis therapy for HCC.
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Longbotham JE, Levy C, Johannissen LO, Tarhonskaya H, Jiang S, Loenarz C, Flashman E, Hay S, Schofield CJ, Scrutton NS. Structure and Mechanism of a Viral Collagen Prolyl Hydroxylase. Biochemistry 2015; 54:6093-105. [PMID: 26368022 PMCID: PMC4613865 DOI: 10.1021/acs.biochem.5b00789] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The
Fe(II)- and 2-oxoglutarate (2-OG)-dependent dioxygenases comprise
a large and diverse enzyme superfamily the members of which have multiple
physiological roles. Despite this diversity, these enzymes share a
common chemical mechanism and a core structural fold, a double-stranded
β-helix (DSBH), as well as conserved active site residues. The
prolyl hydroxylases are members of this large superfamily. Prolyl
hydroxylases are involved in collagen biosynthesis and oxygen sensing
in mammalian cells. Structural–mechanistic studies with prolyl
hydroxylases have broader implications for understanding mechanisms
in the Fe(II)- and 2-OG-dependent dioxygenase superfamily. Here, we
describe crystal structures of an N-terminally truncated viral collagen
prolyl hydroxylase (vCPH). The crystal structure shows that vCPH contains
the conserved DSBH motif and iron binding active site residues of
2-OG oxygenases. Molecular dynamics simulations are used to delineate
structural changes in vCPH upon binding its substrate. Kinetic investigations
are used to report on reaction cycle intermediates and compare them
to the closest homologues of vCPH. The study highlights the utility
of vCPH as a model enzyme for broader mechanistic analysis of Fe(II)-
and 2-OG-dependent dioxygenases, including those of biomedical interest.
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Affiliation(s)
- James E Longbotham
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, The University of Manchester , Manchester M1 7DN, United Kingdom
| | - Colin Levy
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, The University of Manchester , Manchester M1 7DN, United Kingdom
| | - Linus O Johannissen
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, The University of Manchester , Manchester M1 7DN, United Kingdom
| | - Hanna Tarhonskaya
- Chemistry Research Laboratory, University of Oxford , 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Shuo Jiang
- Chemistry Research Laboratory, University of Oxford , 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Christoph Loenarz
- Chemistry Research Laboratory, University of Oxford , 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Emily Flashman
- Chemistry Research Laboratory, University of Oxford , 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Sam Hay
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, The University of Manchester , Manchester M1 7DN, United Kingdom
| | - Christopher J Schofield
- Chemistry Research Laboratory, University of Oxford , 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Nigel S Scrutton
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, The University of Manchester , Manchester M1 7DN, United Kingdom
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Eleftheriadis T, Pissas G, Antoniadi G, Liakopoulos V, Stefanidis I. Kynurenine, by activating aryl hydrocarbon receptor, decreases erythropoietin and increases hepcidin production in HepG2 cells: A new mechanism for anemia of inflammation. Exp Hematol 2015; 44:60-7.e1. [PMID: 26325330 DOI: 10.1016/j.exphem.2015.08.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/15/2015] [Accepted: 08/23/2015] [Indexed: 11/17/2022]
Abstract
It is known that inadequate erythropoietin (EPO) production contributes to the pathogenesis of anemia of inflammation, although the exact molecular mechanism is unknown. Aryl hydrocarbon receptor (AhR) may compete with hypoxia-inducible factor 2α (HIF-2α), the master regulator of EPO production, for binding with HIF-1β. The effect of kynurenine, an endogenous AhR activator that increases in inflammation, on EPO and hepcidin production was evaluated. HepG2 cells were treated with the hypoxia mimetic CoCl2, kynurenine, the AhR inhibitor CH223191, and combinations of these. EPO and hepcidin production was measured with enzyme-linked immunosorbent assay. HIF-2α and CYP1A1 levels, a transcriptional target of AhR, were assessed by Western blotting. CoCl2 increased EPO production and decreased hepcidin and CYP1A1. Kynurenine exerted the opposite effects. Wherever CH223191 was added, the inhibitor overcorrected kynurenine-induced alterations in both the presence and the absence of CoCl2. Also, treatment with CH223191 alone increased EPO and decreased hepcidin, indicating that there is a degree of constitutive AhR activation, possibly by other endogenous AhR activators. In conclusion, kynurenine, by competing with HIF-2α, may contribute to anemia of inflammation by decreasing EPO and increasing hepcidin production. The fact that inactivation of AhR alone induces EPO makes this transcription factor a potential therapeutic target in situations that require increased EPO.
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Affiliation(s)
| | - Georgios Pissas
- Department of Nephrology, Medical School, University of Thessaly, Larissa, Greece
| | - Georgia Antoniadi
- Department of Nephrology, Medical School, University of Thessaly, Larissa, Greece
| | | | - Ioannis Stefanidis
- Department of Nephrology, Medical School, University of Thessaly, Larissa, Greece
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Esfahani M, Karimi F, Afshar S, Niknazar S, Sohrabi S, Najafi R. Prolyl hydroxylase inhibitors act as agents to enhance the efficiency of cell therapy. Expert Opin Biol Ther 2015; 15:1739-55. [PMID: 26325448 DOI: 10.1517/14712598.2015.1084281] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
INTRODUCTION In stem cell-based therapy as a subtype of regenerative medicine, stem cells can be used to replace or repair injured tissue and cells in order to treat disease. Stem cells have the ability to integrate into injured areas and produce new cells via processes of proliferation and differentiation. Several studies have demonstrated that hypoxia increases self-renewal, proliferation and post-homing differentiation of stem cells through the regulation of hypoxia-inducible factor-1 (HIF-1)-mediated gene expression. Thus, pharmacological interventions including prolyl hydroxylase (PHD) inhibitors are considered as promising solutions for stem cell-based therapy. PHD inhibitors stabilize the HIF-1 and activate its pathway through preventing proteasomal degradation of HIF-1. AREAS COVERED This review focuses on the role of hypoxia, HIF-1 and especially PHD inhibitors on cell therapy. PHD structure and function are discussed as well as their inhibitors. In addition, we have investigated several preclinical studies in which PHD inhibitors improved the efficiency of cell-based therapies. EXPERT OPINION The data reviewed here suggest that PHD inhibitors are effective operators in improving stem cell therapy. However, because of some limitations, these compounds should be properly examined before clinical application.
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Affiliation(s)
- Maryam Esfahani
- a 1 Research center for molecular medicine, Hamadan University of Medical Sciences , Hamadan, the Islamic Republic of Iran
| | - Fatemeh Karimi
- a 1 Research center for molecular medicine, Hamadan University of Medical Sciences , Hamadan, the Islamic Republic of Iran
| | - Saeid Afshar
- a 1 Research center for molecular medicine, Hamadan University of Medical Sciences , Hamadan, the Islamic Republic of Iran
| | - Somayeh Niknazar
- b 2 Shahid Beheshti University of Medical Science, Hearing Disorders Research Center , Tehran, the Islamic Republic of Iran
| | - Sareh Sohrabi
- a 1 Research center for molecular medicine, Hamadan University of Medical Sciences , Hamadan, the Islamic Republic of Iran
| | - Rezvan Najafi
- a 1 Research center for molecular medicine, Hamadan University of Medical Sciences , Hamadan, the Islamic Republic of Iran
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Hancock RL, Dunne K, Walport LJ, Flashman E, Kawamura A. Epigenetic regulation by histone demethylases in hypoxia. Epigenomics 2015; 7:791-811. [PMID: 25832587 DOI: 10.2217/epi.15.24] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The response to hypoxia is primarily mediated by the hypoxia-inducible transcription factor (HIF). Levels of HIF are regulated by the oxygen-sensing HIF hydroxylases, members of the 2-oxoglutarate (2OG) dependent oxygenase family. JmjC-domain containing histone lysine demethylases (JmjC-KDMs), also members of the 2OG oxygenase family, are key epigenetic regulators that modulate the methylation levels of histone tails. Kinetic studies of the JmjC-KDMs indicate they could also act in an oxygen-sensitive manner. This may have important implications for epigenetic regulation in hypoxia. In this review we examine evidence that the levels and activity of JmjC-KDMs are sensitive to oxygen availability, and consider how this may influence their roles in early development and hypoxic disease states including cancer and cardiovascular disease.
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Affiliation(s)
- Rebecca L Hancock
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine, BHF Centre of Research Excellence, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Kate Dunne
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine, BHF Centre of Research Excellence, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Louise J Walport
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Emily Flashman
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Akane Kawamura
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine, BHF Centre of Research Excellence, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
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67
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Ye Z, Jin H, Qian Q. Argonaute 2: A Novel Rising Star in Cancer Research. J Cancer 2015; 6:877-82. [PMID: 26284139 PMCID: PMC4532985 DOI: 10.7150/jca.11735] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/15/2015] [Indexed: 12/18/2022] Open
Abstract
AGO2 (Argonaute 2, EIF2C2) is the only member in AGO family with catalytic activity and of extreme importance during small RNAs guided gene silencing processes. The structural investigations have provided insights into details and functional mechanisms of the four major domains within AGO2. As a multifunction player, AGO2 has been revealed involved in tumorgenesis through miRNAs-dependent or independent ways. And nowadays, AGO2 has also been more importantly found ectopically over-expressed in carcinomas and closely associated with aspects of cancers in means of interacting with well-known tumor factors. Here, we provide a review on structural insights, functional mechanisms, novel roles and relationship with carcinomas of AGO2.
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Affiliation(s)
- ZhenLong Ye
- Laboratory of Viral and Gene Therapy, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - HuaJun Jin
- Laboratory of Viral and Gene Therapy, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - QiJun Qian
- Laboratory of Viral and Gene Therapy, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
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68
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Salminen A, Haapasalo A, Kauppinen A, Kaarniranta K, Soininen H, Hiltunen M. Impaired mitochondrial energy metabolism in Alzheimer's disease: Impact on pathogenesis via disturbed epigenetic regulation of chromatin landscape. Prog Neurobiol 2015; 131:1-20. [PMID: 26001589 DOI: 10.1016/j.pneurobio.2015.05.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 05/05/2015] [Accepted: 05/11/2015] [Indexed: 12/14/2022]
Abstract
The amyloid cascade hypothesis for the pathogenesis of Alzheimer's disease (AD) was proposed over twenty years ago. However, the mechanisms of neurodegeneration and synaptic loss have remained elusive delaying the effective drug discovery. Recent studies have revealed that amyloid-β peptides as well as phosphorylated and fragmented tau proteins accumulate within mitochondria. This process triggers mitochondrial fission (fragmentation) and disturbs Krebs cycle function e.g. by inhibiting the activity of 2-oxoglutarate dehydrogenase. Oxidative stress, hypoxia and calcium imbalance also disrupt the function of Krebs cycle in AD brains. Recent studies on epigenetic regulation have revealed that Krebs cycle intermediates control DNA and histone methylation as well as histone acetylation and thus they have fundamental roles in gene expression. DNA demethylases (TET1-3) and histone lysine demethylases (KDM2-7) are included in the family of 2-oxoglutarate-dependent oxygenases (2-OGDO). Interestingly, 2-oxoglutarate is the obligatory substrate of 2-OGDO enzymes, whereas succinate and fumarate are the inhibitors of these enzymes. Moreover, citrate can stimulate histone acetylation via acetyl-CoA production. Epigenetic studies have revealed that AD is associated with changes in DNA methylation and histone acetylation patterns. However, the epigenetic results of different studies are inconsistent but one possibility is that they represent both coordinated adaptive responses and uncontrolled stochastic changes, which provoke pathogenesis in affected neurons. Here, we will review the changes observed in mitochondrial dynamics and Krebs cycle function associated with AD, and then clarify the mechanisms through which mitochondrial metabolites can control the epigenetic landscape of chromatin and induce pathological changes in AD.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland.
| | - Annakaisa Haapasalo
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Anu Kauppinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Hilkka Soininen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Mikko Hiltunen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland; Institute of Biomedicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland
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Wang H, Huang C, Chen N, Zhu K, Chen B, Wang W, Wang H. Molecular characterization and mRNA expression of HIF-prolyl hydroxylase-2 (phd2) in hypoxia-sensing pathways from Megalobrama amblycephala. Comp Biochem Physiol B Biochem Mol Biol 2015; 186:28-35. [PMID: 25868626 DOI: 10.1016/j.cbpb.2015.04.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 03/19/2015] [Accepted: 04/01/2015] [Indexed: 12/19/2022]
Abstract
HIF-prolyl-hydroxylase-2 (Phd2), a member of the iron (II) and 2-oxoglutarate-dependent dioxygenase family, is one of the key enzymes in hypoxia-sensing pathways. In this study, the phd2 cDNA sequence (1231bp), including an open reading frame (ORF) and encoding 358 amino acid residues was identified in Megalobrama amblycephala (Wuchang bream). The predicted Phd2 protein contained three conserved domains, MYND type zinc finger domain with critical regulatory activity, Fe(2+)-dependent 2OG-Fe (II) oxygenase superfamily domain with prolyl hydroxylase function, and P4Hc (prolyl 4-hydroxylase alpha subunit homologues) domain for catalyzing proline hydroxylation. The real-time PCR results showed that phd2 mRNA was ubiquitously expressed in all detected tissues with higher levels in the peripheral blood, heart and brain, and all embryogenesis stages, especially in mid-blastula stage. In larvae M. amblycephala, the expression trend of the phd2 and hypoxia-inducible factor 1 alpha (hif-1α) mRNA was opposite during hypoxia with an increase (hypoxia for 4h) and then decrease (hypoxia for 12h) for phd2. Whereas in adult fish, the phd2 mRNA appeared a transient increase under hypoxia for 4h (DO: 3.46±0.59 mg/L), and dramatically reduced with further hypoxia exposure to 12h in the peripheral blood, muscle, head kidney, liver and brain, but showed an opposite expression trend in the heart and gill. The hif-1α expression was contrary with phd2 in the peripheral blood, while it gradually decreased in the heart, but increased in the liver with continuous hypoxia treatment. Additionally, hif-1α also showed lower mRNA levels than phd2 in all detected tissues under normoxia and hypoxia conditions.
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Affiliation(s)
- Huijuan Wang
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery, Huazhong Agricultural University, 430070, Wuhan, PR China
| | - Chunxiao Huang
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery, Huazhong Agricultural University, 430070, Wuhan, PR China
| | - Nan Chen
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery, Huazhong Agricultural University, 430070, Wuhan, PR China
| | - Kecheng Zhu
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery, Huazhong Agricultural University, 430070, Wuhan, PR China
| | - Boxiang Chen
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery, Huazhong Agricultural University, 430070, Wuhan, PR China; Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, 430070 Wuhan, PR China; Hubei BaiRong Improved Aquatic Seed Co., Ltd, 438800 Huanggang, PR China
| | - Weimin Wang
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery, Huazhong Agricultural University, 430070, Wuhan, PR China; Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, 430070 Wuhan, PR China
| | - Huanling Wang
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Fishery, Huazhong Agricultural University, 430070, Wuhan, PR China; Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, 430070 Wuhan, PR China.
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70
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Depping R, Jelkmann W, Kosyna FK. Nuclear-cytoplasmatic shuttling of proteins in control of cellular oxygen sensing. J Mol Med (Berl) 2015; 93:599-608. [PMID: 25809665 DOI: 10.1007/s00109-015-1276-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 03/04/2015] [Accepted: 03/11/2015] [Indexed: 12/11/2022]
Abstract
In order to pass through the nuclear pore complex, proteins larger than ∼40 kDa require specific nuclear transport receptors. Defects in nuclear-cytoplasmatic transport affect fundamental processes such as development, inflammation and oxygen sensing. The transcriptional response to O2 deficiency is controlled by hypoxia-inducible factors (HIFs). These are heterodimeric transcription factors of each ∼100-120 kDa proteins, consisting of one out of three different O2-labile α subunits (primarily HIF-1α) and a more constitutive 1β subunit. In the presence of O2, the α subunits are hydroxylated by specific prolyl-4-hydroxylase domain proteins (PHD1, PHD2, and PHD3) and an asparaginyl hydroxylase (factor inhibiting HIF-1, FIH-1). The prolyl hydroxylation causes recognition by von Hippel-Lindau tumor suppressor protein (pVHL), ubiquitination, and proteasomal degradation. The activity of the oxygen sensing machinery depends on dynamic intracellular trafficking. Nuclear import of HIF-1α and HIF-1β is mainly mediated by importins α and β (α/β). HIF-1α can shuttle between nucleus and cytoplasm, while HIF-1β is permanently inside the nucleus. pVHL is localized to both compartments. Nuclear import of PHD1 relies on a nuclear localization signal (NLS) and uses the classical import pathway involving importin α/β receptors. PHD2 shows an atypical NLS, and its nuclear import does not occur via the classical pathway. PHD2-mediated hydroxylation of HIF-1α occurs predominantly in the cell nucleus. Nuclear export of PHD2 involves a nuclear export signal (NES) in the N-terminus and depends on the export receptor chromosome region maintenance 1 (CRM1). Nuclear import of PHD3 is mediated by importin α/β receptors and depends on a non-classical NLS. Specific modification of the nuclear translocation of the three PHD isoforms could provide a promising strategy for the development of new therapeutic substances to tackle major diseases.
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Affiliation(s)
- Reinhard Depping
- Institute of Physiology, Centre for Structural and Cell Biology in Medicine, University of Lübeck, Lübeck, Germany,
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71
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Staudacher JJ, Naarmann-de Vries IS, Ujvari SJ, Klinger B, Kasim M, Benko E, Ostareck-Lederer A, Ostareck DH, Bondke Persson A, Lorenzen S, Meier JC, Blüthgen N, Persson PB, Henrion-Caude A, Mrowka R, Fähling M. Hypoxia-induced gene expression results from selective mRNA partitioning to the endoplasmic reticulum. Nucleic Acids Res 2015; 43:3219-36. [PMID: 25753659 PMCID: PMC4381074 DOI: 10.1093/nar/gkv167] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 02/21/2015] [Indexed: 01/01/2023] Open
Abstract
Protein synthesis is a primary energy-consuming process in the cell. Therefore, under hypoxic conditions, rapid inhibition of global mRNA translation represents a major protective strategy to maintain energy metabolism. How some mRNAs, especially those that encode crucial survival factors, continue to be efficiently translated in hypoxia is not completely understood. By comparing specific transcript levels in ribonucleoprotein complexes, cytoplasmic polysomes and endoplasmic reticulum (ER)-bound ribosomes, we show that the synthesis of proteins encoded by hypoxia marker genes is favoured at the ER in hypoxia. Gene expression profiling revealed that transcripts particularly increased by the HIF-1 transcription factor network show hypoxia-induced enrichment at the ER. We found that mRNAs favourably translated at the ER have higher conservation scores for both the 5'- and 3'-untranslated regions (UTRs) and contain less upstream initiation codons (uAUGs), indicating the significance of these sequence elements for sustained mRNA translation under hypoxic conditions. Furthermore, we found enrichment of specific cis-elements in mRNA 5'- as well as 3'-UTRs that mediate transcript localization to the ER in hypoxia. We conclude that transcriptome partitioning between the cytoplasm and the ER permits selective mRNA translation under conditions of energy shortage.
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Affiliation(s)
- Jonas J Staudacher
- Charité - Universitätsmedizin Berlin, Institut für Vegetative Physiologie, Charitéplatz 1, D-10117 Berlin, Germany
| | - Isabel S Naarmann-de Vries
- University Hospital Aachen, RWTH Aachen University, Department of Intensive and Intermediate Care, Experimental Research Unit, D-52074 Aachen, Germany
| | - Stefanie J Ujvari
- Charité - Universitätsmedizin Berlin, Institut für Vegetative Physiologie, Charitéplatz 1, D-10117 Berlin, Germany
| | - Bertram Klinger
- Humboldt Universität zu Berlin, Institut für Theoretische Biologie, D-10115 Berlin, Germany Charité - Universitätsmedizin Berlin, Institut für Pathologie, D-10117 Berlin, Germany
| | - Mumtaz Kasim
- Charité - Universitätsmedizin Berlin, Institut für Vegetative Physiologie, Charitéplatz 1, D-10117 Berlin, Germany
| | - Edgar Benko
- Charité - Universitätsmedizin Berlin, Institut für Vegetative Physiologie, Charitéplatz 1, D-10117 Berlin, Germany
| | - Antje Ostareck-Lederer
- University Hospital Aachen, RWTH Aachen University, Department of Intensive and Intermediate Care, Experimental Research Unit, D-52074 Aachen, Germany
| | - Dirk H Ostareck
- University Hospital Aachen, RWTH Aachen University, Department of Intensive and Intermediate Care, Experimental Research Unit, D-52074 Aachen, Germany
| | - Anja Bondke Persson
- Charité - Universitätsmedizin Berlin, Institut für Vegetative Physiologie, Charitéplatz 1, D-10117 Berlin, Germany
| | - Stephan Lorenzen
- Universitätsklinikum Jena, Klinik für Innere Medizin III, AG Experimentelle Nephrologie, D-07743 Jena, Germany
| | - Jochen C Meier
- Max Delbrück Center for Molecular Medicine, RNA Editing and Hyperexcitability Disorders Helmholtz Group, D-13125 Berlin, Germany TU Braunschweig, Zoological Institute, Division of Cell Physiology, D-38106 Braunschweig, Germany
| | - Nils Blüthgen
- Humboldt Universität zu Berlin, Institut für Theoretische Biologie, D-10115 Berlin, Germany Charité - Universitätsmedizin Berlin, Institut für Pathologie, D-10117 Berlin, Germany
| | - Pontus B Persson
- Charité - Universitätsmedizin Berlin, Institut für Vegetative Physiologie, Charitéplatz 1, D-10117 Berlin, Germany
| | - Alexandra Henrion-Caude
- Hôpital Necker-Enfants Malades, Université Paris Descartes, Institut National de la Santé et de la Recherche Médicale (INSERM) UMR1163 and Imagine Foundation, 75015 Paris, France
| | - Ralf Mrowka
- Universitätsklinikum Jena, Klinik für Innere Medizin III, AG Experimentelle Nephrologie, D-07743 Jena, Germany
| | - Michael Fähling
- Charité - Universitätsmedizin Berlin, Institut für Vegetative Physiologie, Charitéplatz 1, D-10117 Berlin, Germany
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Jeong S, Park H, Hong S, Yum S, Kim W, Jung Y. Lipophilic modification enhances anti-colitic properties of rosmarinic acid by potentiating its HIF-prolyl hydroxylases inhibitory activity. Eur J Pharmacol 2015; 747:114-22. [PMID: 25483211 DOI: 10.1016/j.ejphar.2014.11.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/21/2014] [Accepted: 11/24/2014] [Indexed: 12/22/2022]
Abstract
Inhibition of hypoxia inducible factor-prolyl hydroxylase-2 (HPH), leading to activation of hypoxia inducible factor (HIF)-1 is a potential therapeutic strategy for the treatment of colitis. Rosmarinic acid (RA), an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid is a naturally occurring polyphenolic compound with two catechols, a or inhibition of HPH. To improve accessibility of highly hydrophilic RA to HPH, an intracellular target, RA was chemically modified to decrease hydrophilicity. Of the less-hydrophilic derivatives, rosmarinic acid methyl ester (RAME) most potently inhibited HPH. Accordingly, RAME prevented hydroxylation of HIF-1α and consequently stabilized HIF-1α protein in cells. RAME inhibition of HPH and induction of HIF-1α were diminished by elevated doses of the required factors of HPH, 2-ketoglutarate and ascorbate. RAME induction of HIF-1α led to activation of an ulcer healing pathway, HIF-1-vascular endothelial growth factor (VEGF), in human colon carcinoma cells. RAME administered rectally ameliorated TNBS-induced rat colitis and substantially decreased the levels of pro-inflammatory mediators in the inflamed colonic tissue. In parallel with the cellular effects of RAME, RAME up-regulated HIF-1α and VEGF in the inflamed colonic tissue. Thus, lipophilic modification of RA improves its ability to inhibit HPH, leading to activation of the HIF-1-VEGF pathway. RAME, a lipophilic RA derivative, may exert anti-colitic effects via activation of the ulcer healing pathway.
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Affiliation(s)
- Seongkeun Jeong
- College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Huijeong Park
- College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Sungchae Hong
- College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Soohwan Yum
- College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Wooseong Kim
- College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Yunjin Jung
- College of Pharmacy, Pusan National University, Busan, Republic of Korea.
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73
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Bishop T, Ratcliffe PJ. Signaling hypoxia by hypoxia-inducible factor protein hydroxylases: a historical overview and future perspectives. HYPOXIA 2014; 2:197-213. [PMID: 27774477 PMCID: PMC5045067 DOI: 10.2147/hp.s47598] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
By the early 1900s, the close matching of oxygen supply with demand was recognized to be a fundamental requirement for physiological function, and multiple adaptive responses to environment hypoxia had been described. Nevertheless, the widespread operation of mechanisms that directly sense and respond to levels of oxygen in animal cells was not appreciated for most of the twentieth century with investigators generally stressing the regulatory importance of metabolic products. Work over the last 25 years has overturned that paradigm. It has revealed the existence of a set of “oxygen-sensing” 2-oxoglutarate dependent dioxygenases that catalyze the hydroxylation of specific amino acid residues and thereby control the stability and activity of hypoxia-inducible factor. The hypoxia-inducible factor hydroxylase pathway regulates a massive transcriptional cascade that is operative in essentially all animal cells. It transduces a wide range of responses to hypoxia, extending well beyond the classical boundaries of hypoxia physiology. Here we review the discovery and elucidation of these pathways, and consider the opportunities and challenges that have been brought into focus by the findings, including new implications for the integrated physiology of hypoxia and therapeutic approaches to ischemic/hypoxic disease.
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Affiliation(s)
- Tammie Bishop
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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74
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García-Heredia JM, Felipe-Abrio B, Cano DA, Carnero A. Genetic modification of hypoxia signaling in animal models and its effect on cancer. Clin Transl Oncol 2014; 17:90-102. [PMID: 25351170 DOI: 10.1007/s12094-014-1236-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 09/24/2014] [Indexed: 12/19/2022]
Abstract
Conditions that cause hypoxemia or generalized tissue hypoxia, which can last for days, months, or even years, are very common in the human population and are among the leading causes of morbidity, disability, and mortality. Therefore, the molecular pathophysiology of hypoxia and its potential deleterious effects on human health are important issues at the forefront of biomedical research. Generalized hypoxia is a consequence of highly prevalent medical disorders that can severely reduce the capacity for O2 exchange between the air and pulmonary capillaries. In recent years, some of the key O2-dependent signaling pathways have been characterized at the molecular level. In particular, the prolyl hydroxylase (PHD)-hypoxia-inducible factor (HIF) cascade has emerged as the master regulator of a general gene expression program involved in cell/tissue/organ adaptation to hypoxia. Hypoxia has emerged as a critical factor in cancer because it can promote tumor initiation, progression, and resistance to therapy. Beyond its role in neovascularization as a mechanism of tumor adaptation to nutrient and O2 deprivation, hypoxia has been linked to prolonged cellular lifespan and immortalization, the generation of "oncometabolites", deregulation of stem cell proliferation, and inflammation, among other tumor hallmarks. Hypoxia may contribute to cancer through several independent pathways, the inter-connections of which have yet to be elucidated. Furthermore, the relevance of chronic hypoxemia in the initiation and progression of cancer has not been studied in depth in the whole organism. Therefore, we explore here the contributions of hypoxia to the whole organism by reviewing studies on genetically modified mice with alterations in the key molecular factors regulating hypoxia.
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Affiliation(s)
- J M García-Heredia
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla, 41013, Seville, Spain
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75
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Rahtu-Korpela L, Karsikas S, Hörkkö S, Blanco Sequeiros R, Lammentausta E, Mäkelä KA, Herzig KH, Walkinshaw G, Kivirikko KI, Myllyharju J, Serpi R, Koivunen P. HIF prolyl 4-hydroxylase-2 inhibition improves glucose and lipid metabolism and protects against obesity and metabolic dysfunction. Diabetes 2014; 63:3324-33. [PMID: 24789921 DOI: 10.2337/db14-0472] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Obesity is a major public health problem, predisposing subjects to metabolic syndrome, type 2 diabetes, and cardiovascular diseases. Specific prolyl 4-hydroxylases (P4Hs) regulate the stability of the hypoxia-inducible factor (HIF), a potent governor of metabolism, with isoenzyme 2 being the main regulator. We investigated whether HIF-P4H-2 inhibition could be used to treat obesity and its consequences. Hif-p4h-2-deficient mice, whether fed normal chow or a high-fat diet, had less adipose tissue, smaller adipocytes, and less adipose tissue inflammation than their littermates. They also had improved glucose tolerance and insulin sensitivity. Furthermore, the mRNA levels of the HIF-1 targets glucose transporters, glycolytic enzymes, and pyruvate dehydrogenase kinase-1 were increased in their tissues, whereas acetyl-CoA concentration was decreased. The hepatic mRNA level of the HIF-2 target insulin receptor substrate-2 was higher, whereas that of two key enzymes of fatty acid synthesis was lower. Serum cholesterol levels and de novo lipid synthesis were decreased, and the mice were protected against hepatic steatosis. Oral administration of an HIF-P4H inhibitor, FG-4497, to wild-type mice with metabolic dysfunction phenocopied these beneficial effects. HIF-P4H-2 inhibition may be a novel therapy that not only protects against the development of obesity and its consequences but also reverses these conditions.
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Affiliation(s)
- Lea Rahtu-Korpela
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, Oulu Center for Cell-Matrix Research, University of Oulu, FIN-90014 Oulu, Finland
| | - Sara Karsikas
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, Oulu Center for Cell-Matrix Research, University of Oulu, FIN-90014 Oulu, Finland
| | - Sohvi Hörkkö
- Nordlab Oulu, Oulu University Hospital, FIN-90220 Oulu, Finland Department of Medical Microbiology and Immunology, Medical Research Center, University of Oulu, FIN-90014 Oulu, Finland
| | - Roberto Blanco Sequeiros
- Department of Radiology, Oulu University Hospital and University of Oulu, FIN-90029 Oulu, Finland
| | - Eveliina Lammentausta
- Department of Radiology, Oulu University Hospital and University of Oulu, FIN-90029 Oulu, Finland
| | - Kari A Mäkelä
- Biocenter Oulu, Department of Physiology, University of Oulu, FIN-90014 Oulu, Finland
| | - Karl-Heinz Herzig
- Biocenter Oulu, Department of Physiology, University of Oulu, FIN-90014 Oulu, Finland
| | | | - Kari I Kivirikko
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, Oulu Center for Cell-Matrix Research, University of Oulu, FIN-90014 Oulu, Finland
| | - Johanna Myllyharju
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, Oulu Center for Cell-Matrix Research, University of Oulu, FIN-90014 Oulu, Finland
| | - Raisa Serpi
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, Oulu Center for Cell-Matrix Research, University of Oulu, FIN-90014 Oulu, Finland
| | - Peppi Koivunen
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, Oulu Center for Cell-Matrix Research, University of Oulu, FIN-90014 Oulu, Finland
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A prolyl-hydroxylase inhibitor, ethyl-3,4-dihydroxybenzoate, induces cell autophagy and apoptosis in esophageal squamous cell carcinoma cells via up-regulation of BNIP3 and N-myc downstream-regulated gene-1. PLoS One 2014; 9:e107204. [PMID: 25232961 PMCID: PMC4169646 DOI: 10.1371/journal.pone.0107204] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 08/12/2014] [Indexed: 12/14/2022] Open
Abstract
The protocatechuic acid ethyl ester ethyl-3,4-dihydroxybenzoate is an antioxidant found in the testa of peanut seeds. Previous studies have shown that ethyl-3,4-dihydroxybenzoate can effectively reduce breast cancer cell metastasis by inhibiting prolyl-hydroxylase. In this study, we investigated the cytotoxic effect of ethyl-3,4-dihydroxybenzoate on esophageal squamous cell carcinoma cells in vitro and identified key regulators of ethyl-3,4-dihydroxybenzoate-induced esophageal cancer cell death through transcription expression profiling. Using flow cytometry analysis, we found that ethyl-3,4-dihydroxybenzoate induced S phase accumulation, a loss in mitochondrial membrane permeabilization, and caspase-dependent apoptosis. Moreover, an expression profile analysis identified 46 up- and 9 down-regulated genes in esophageal cancer KYSE 170 cells treated with ethyl-3,4-dihydroxybenzoate. These differentially expressed genes are involved in several signaling pathways associated with cell cycle regulation and cellular metabolism. Consistent with the expression profile results, the transcriptional and protein expression levels of candidate genes NDRG1, BNIP3, AKR1C1, CCNG2 and VEGFA were found to be significantly increased in treated KYSE 170 cells by reverse-transcription PCR and western blot analysis. We also found that protein levels of hypoxia-inducible factor-1α, BNIP3, Beclin and NDRG1 were increased and that enriched expression of BNIP3 and Beclin caused autophagy mediated by microtubule-associated protein 1 light chain 3 in the treated cells. Autophagy and apoptosis were activated together in esophageal cancer cells after exposed to ethyl-3,4-dihydroxybenzoate. Furthermore, knock-down of NDRG1 expression by siRNA significantly attenuated apoptosis in the cancer cells, implying that NDRG1 may be required for ethyl-3,4-dihydroxybenzoate-induced apoptosis. Together, these results suggest that the cytotoxic effects of ethyl-3,4-dihydroxybenzoate were mediated by the up-regulation of NDRG1, BNIP3, Beclin and hypoxia-inducible factor-1α, initiating BNIP3 and Beclin mediated autophagy at an early stage and ultimately resulting in esophageal cancer cell apoptosis.
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Ruthenborg RJ, Ban JJ, Wazir A, Takeda N, Kim JW. Regulation of wound healing and fibrosis by hypoxia and hypoxia-inducible factor-1. Mol Cells 2014; 37:637-43. [PMID: 24957212 PMCID: PMC4179131 DOI: 10.14348/molcells.2014.0150] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 06/08/2014] [Indexed: 12/12/2022] Open
Abstract
Wound healing is a complex multi-step process that requires spatial and temporal orchestration of cellular and non-cellular components. Hypoxia is one of the prominent microenvironmental factors in tissue injury and wound healing. Hypoxic responses, mainly mediated by a master transcription factor of oxygen homeostasis, hypoxia-inducible factor-1 (HIF-1), have been shown to be critically involved in virtually all processes of wound healing and remodeling. Yet, mechanisms underlying hypoxic regulation of wound healing are still poorly understood. Better understanding of how the wound healing process is regulated by the hypoxic microenvironment and HIF-1 signaling pathway will provide insight into the development of a novel therapeutic strategy for impaired wound healing conditions such as diabetic wound and fibrosis. In this review, we will discuss recent studies illuminating the roles of HIF-1 in physiologic and pathologic wound repair and further, the therapeutic potentials of HIF-1 stabilization or inhibition.
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Affiliation(s)
- Robin J Ruthenborg
- Department of Molecular and Cell Biology, The University of Texas at Dallas, Richardson TX 75080, USA
| | - Jae-Jun Ban
- Department of Molecular and Cell Biology, The University of Texas at Dallas, Richardson TX 75080, USA
| | - Anum Wazir
- Department of Molecular and Cell Biology, The University of Texas at Dallas, Richardson TX 75080, USA
| | | | - Jung-whan Kim
- Department of Molecular and Cell Biology, The University of Texas at Dallas, Richardson TX 75080, USA
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78
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Salminen A, Kauppinen A, Hiltunen M, Kaarniranta K. Krebs cycle intermediates regulate DNA and histone methylation: epigenetic impact on the aging process. Ageing Res Rev 2014; 16:45-65. [PMID: 24910305 DOI: 10.1016/j.arr.2014.05.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 05/20/2014] [Accepted: 05/29/2014] [Indexed: 02/01/2023]
Abstract
Many aging theories have proposed that mitochondria and energy metabolism have a major role in the aging process. There are recent studies indicating that Krebs cycle intermediates can shape the epigenetic landscape of chromatin by regulating DNA and histone methylation. A growing evidence indicates that epigenetics plays an important role in the regulation of healthspan but also is involved in the aging process. 2-Oxoglutarate (α-ketoglutarate) is a key metabolite in the Krebs cycle but it is also an obligatory substrate for 2-oxoglutarate-dependent dioxygenases (2-OGDO). The 2-OGDO enzyme family includes the major enzymes of DNA and histone demethylation, i.e. Ten-Eleven Translocation (TETs) and Jumonji C domain containing (JmjC) demethylases. In addition, 2-OGDO members can regulate collagen synthesis and hypoxic responses in a non-epigenetical manner. Interestingly, succinate and fumarate, also Krebs cycle intermediates, are potent inhibitors of 2-OGDO enzymes, i.e. the balance of Krebs cycle reactions can affect the level of DNA and histone methylation and thus control gene expression. We will review the epigenetic mechanisms through which Krebs cycle intermediates control the DNA and histone methylation. We propose that age-related disturbances in the Krebs cycle function induce stochastic epigenetic changes in chromatin structures which in turn promote the aging process.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland.
| | - Anu Kauppinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland
| | - Mikko Hiltunen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland
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79
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Zieseniss A. Hypoxia and the modulation of the actin cytoskeleton - emerging interrelations. HYPOXIA 2014; 2:11-21. [PMID: 27774463 PMCID: PMC5045051 DOI: 10.2147/hp.s53575] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recent progress in understanding the influence of hypoxia on cell function has revealed new information about the interrelationship between the actin cytoskeleton and hypoxia; nevertheless, details remain cloudy. The dynamic regulation of the actin cytoskeleton during hypoxia is complex, varies in different cells and tissues, and also depends on the mode of hypoxia. Several molecular players and pathways are emerging that contribute to the modulation of the actin cytoskeleton and that affect the large repertoire of actin-binding proteins in hypoxia. This review describes and discusses the accumulated knowledge about actin cytoskeleton dynamics in hypoxia, placing special emphasis on the Rho family of small guanosine triphosphatases (Rho GTPases). Given that RhoA, Rac and Cdc42 are very well characterized, the review is focused on these family members of Rho GTPases. Notably, in several cell types and tissues, hypoxia, presumably via Rho GTPase signaling, induces actin rearrangement and actin stress fiber assembly, which is a prevalent modulation of the actin cytoskeleton in hypoxia.
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Affiliation(s)
- Anke Zieseniss
- Institute of Cardiovascular Physiology, University Medical Center, Georg-August University, Göttingen, Germany
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80
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Shah YM, Xie L. Hypoxia-inducible factors link iron homeostasis and erythropoiesis. Gastroenterology 2014; 146:630-42. [PMID: 24389303 PMCID: PMC3943938 DOI: 10.1053/j.gastro.2013.12.031] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/06/2013] [Accepted: 12/10/2013] [Indexed: 12/15/2022]
Abstract
Iron is required for efficient oxygen transport, and hypoxia signaling links erythropoiesis with iron homeostasis. Hypoxia induces a highly conserved signaling pathway in cells under conditions of low levels of O2. One component of this pathway, hypoxia-inducible factor (HIF), is a transcription factor that is highly active in hypoxic cells. The first HIF target gene characterized was EPO, which encodes erythropoietin-a glycoprotein hormone that controls erythropoiesis. In the past decade, there have been fundamental advances in our understanding of how hypoxia regulates iron levels to support erythropoiesis and maintain systemic iron homeostasis. We review the cell type-specific effects of hypoxia and HIFs in adaptive response to changes in oxygen and iron availability as well as potential uses of HIF modulators for patients with iron-related disorders.
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Affiliation(s)
- Yatrik M. Shah
- Department of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan, Ann Arbor, Michigan,Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, Michigan, To whom correspondence should be addressed. Tel: +1 734 6150567; Fax: +1 734 9368813;
| | - Liwei Xie
- Department of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan, Ann Arbor, Michigan
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81
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Masson N, Ratcliffe PJ. Hypoxia signaling pathways in cancer metabolism: the importance of co-selecting interconnected physiological pathways. Cancer Metab 2014; 2:3. [PMID: 24491179 PMCID: PMC3938304 DOI: 10.1186/2049-3002-2-3] [Citation(s) in RCA: 217] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 01/22/2014] [Indexed: 12/31/2022] Open
Abstract
Both tumor hypoxia and dysregulated metabolism are classical features of cancer. Recent analyses have revealed complex interconnections between oncogenic activation, hypoxia signaling systems and metabolic pathways that are dysregulated in cancer. These studies have demonstrated that rather than responding simply to error signals arising from energy depletion or tumor hypoxia, metabolic and hypoxia signaling pathways are also directly connected to oncogenic signaling mechanisms at many points. This review will summarize current understanding of the role of hypoxia inducible factor (HIF) in these networks. It will also discuss the role of these interconnected pathways in generating the cancer phenotype; in particular, the implications of switching massive pathways that are physiologically 'hard-wired’ to oncogenic mechanisms driving cancer.
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Affiliation(s)
| | - Peter J Ratcliffe
- The Hypoxia Biology Laboratory, The Henry Wellcome Building for Molecular Physiology, The University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
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82
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Rosenow A, Noben JP, Bouwman FG, Mariman ECM, Renes J. Hypoxia-mimetic effects in the secretome of human preadipocytes and adipocytes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2761-71. [PMID: 24140569 DOI: 10.1016/j.bbapap.2013.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 09/16/2013] [Accepted: 10/03/2013] [Indexed: 10/26/2022]
Abstract
White adipose tissue (WAT) regulates energy metabolism by secretion of proteins with endocrine and paracrine effects. Dysregulation of the secretome of obesity-associated enlarged WAT may lead to obesity-related disorders. This can be caused by hypoxia as a result of poorly vascularized WAT. The effect of hypoxia on the secretome of human (pre)adipocytes is largely unknown. Therefore, we investigated the effect of CoCl2, a hypoxia mimetic, on the secretome of human SGBS (pre)adipocytes by a proteomics approach combined with bioinformatic analysis. In addition, regulation of protein secretion was examined by protein turnover experiments. As such, secretome changes were particularly associated with protein down-regulation and extracellular matrix protein dysregulation. The observed up-regulation of collagens in adipocytes may be essential for cell survival while down-regulation of collagens in preadipocytes may indicate a disturbed differentiation process. These CoCl2-induced changes reflect WAT dysfunction that ultimately may lead to obesity-associated complications. In addition, 9 novel adipocyte secreted proteins were identified from which 6 were regulated by CoCl2. Mass spectrometry data have been deposited to the ProteomeXchange with identifier PXD000162.
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Affiliation(s)
- Anja Rosenow
- NUTRIM School for Nutrition, Toxicology and Metabolism, Department of Human Biology, Maastricht University, Maastricht, The Netherlands.
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83
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Takahashi E, Sato M. Anaerobic respiration sustains mitochondrial membrane potential in a prolyl hydroxylase pathway-activated cancer cell line in a hypoxic microenvironment. Am J Physiol Cell Physiol 2013; 306:C334-42. [PMID: 24048731 DOI: 10.1152/ajpcell.00255.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
To elucidate how tumor cells produce energy in oxygen-depleted microenvironments, we studied the possibility of mitochondrial electron transport without oxygen. We produced well-controlled oxygen gradients (ΔO2) in monolayer-cultured cells. We then visualized oxygen levels and mitochondrial membrane potential (ΔΦm) in individual cells by using the red shift of green fluorescent protein (GFP) fluorescence and a cationic fluorescent dye, respectively. In this two-dimensional tissue model, ΔΦm was abolished in cells >500 μm from the oxygen source [the anoxic front (AF)], indicating limitations in diffusional oxygen delivery. This result perfectly matched GFP-determined ΔO2. In cells pretreated with dimethyloxaloylglycine (DMOG), a prolyl hydroxylase domain-containing protein (PHD) inhibitor, the AF was expanded to 1,500-2,000 μm from the source. In these cells, tissue ΔO2 was substantially decreased, indicating that PHD pathway activation suppressed mitochondrial respiration. The expansion of the AF and the reduction of ΔO2 were much more prominent in a cancer cell line (Hep3B) than in the equivalent fibroblast-like cell line (COS-7). Hence, the results indicate that PHD pathway-activated cells can sustain ΔΦm, despite significantly decreased electron flux to complex IV. Complex II inhibition abolished the effect of DMOG in expanding the AF, although tissue ΔO2 remained shallow. Separate experiments demonstrated that complex II plays a substantial role in sustaining ΔΦm in DMOG-pretreated Hep3B cells with complex III inhibition. From these results, we conclude that PHD pathway activation can sustain ΔΦm in an otherwise anoxic microenvironment by decreasing tissue ΔO2 while activating oxygen-independent electron transport in mitochondria.
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Affiliation(s)
- Eiji Takahashi
- Advanced Technology Fusion, Graduate School of Science and Engineering, Saga University, Saga, Japan; and
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Affiliation(s)
- M. Nikinmaa
- Department of Biology; University of Turku; Turku; Finland
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