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Beuck S, Schänzer W, Thevis M. Hypoxia-inducible factor stabilizers and other small-molecule erythropoiesis-stimulating agents in current and preventive doping analysis. Drug Test Anal 2012; 4:830-45. [PMID: 22362605 DOI: 10.1002/dta.390] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Revised: 10/21/2011] [Accepted: 10/22/2011] [Indexed: 12/12/2022]
Abstract
Increasing the blood's capacity for oxygen transport by erythropoiesis-stimulating agents (ESAs) constitutes a prohibited procedure of performance enhancement according to the World Anti-Doping Agency (WADA). The advent of orally bio-available small-molecule ESAs such as hypoxia-inducible factor (HIF) stabilizers in the development of novel anti-anaemia therapies expands the list of potential ESA doping techniques. Here, the erythropoiesis-stimulating properties and doping relevance of experimental HIF-stabilizers, such as cobaltous chloride, 3,4-dihydroxybenzoic acid or GSK360A, amongst others, are discussed. The stage of clinical trials is reviewed for the anti-anaemia drug candidates FG-2216, FG-4592, GSK1278863, AKB-6548, and BAY85-3934. Currently available methods and strategies for the determination of selected HIF stabilizers in sports drug testing are based on liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). For the support of further analytical assay development, patents claiming distinct compounds for the use in HIF-mediated therapies are evaluated and exemplary molecular structures of HIF stabilizers presented. Moreover, data concerning the erythropoiesis-enhancing effects of the GATA inhibitors K7174 and K11706 as well as the lipidic small-molecule ESA PBI-1402 are elucidated the context of doping analysis.
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Affiliation(s)
- Simon Beuck
- German Sport University Cologne, Cologne, Germany
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52
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Sefcik LS, Petrie Aronin CE, Botchwey EA. Engineering vascularized tissues using natural and synthetic small molecules. Organogenesis 2012; 4:215-27. [PMID: 19337401 DOI: 10.4161/org.4.4.6963] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 09/10/2008] [Indexed: 12/21/2022] Open
Abstract
Vascular growth and remodeling are complex processes that depend on the proper spatial and temporal regulation of many different signaling molecules to form functional vascular networks. The ability to understand and regulate these signals is an important clinical need with the potential to treat a wide variety of disease pathologies. Current approaches have focused largely on the delivery of proteins to promote neovascularization of ischemic tissues, most notably VEGF and FGF. Although great progress has been made in this area, results from clinical trials are disappointing and safer and more effective approaches are required. To this end, biological agents used for therapeutic neovascularization must be explored beyond the current well-investigated classes. This review focuses on potential pathways for novel drug discovery, utilizing small molecule approaches to induce and enhance neovascularization. Specifically, four classes of new and existing molecules are discussed, including transcriptional activators, receptor selective agonists and antagonists, natural product-derived small molecules, and novel synthetic small molecules.
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Affiliation(s)
- Lauren S Sefcik
- Department of Biomedical Engineering; and Department of Orthopaedic Surgery; University of Virginia; Charlottesville, Virginia USA; Center for Immunity, Inflammation and Regenerative Medicine (CIIR); University of Virginia; Charlottesville, Virginia USA
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53
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Roda JM, Wang Y, Sumner LA, Phillips GS, Marsh CB, Eubank TD. Stabilization of HIF-2α induces sVEGFR-1 production from tumor-associated macrophages and decreases tumor growth in a murine melanoma model. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 189:3168-77. [PMID: 22869907 PMCID: PMC3436995 DOI: 10.4049/jimmunol.1103817] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Macrophage secretion of vascular endothelial growth factor (VEGF) in response to hypoxia contributes to tumor growth and angiogenesis. In addition to VEGF, hypoxic macrophages stimulated with GM-CSF secrete high levels of a soluble form of the VEGF receptor (sVEGFR-1), which neutralizes VEGF and inhibits its biological activity. Using mice with a monocyte/macrophage-selective deletion of hypoxia-inducible factor (HIF)-1α or HIF-2α, we recently demonstrated that the antitumor response to GM-CSF was dependent on HIF-2α-driven sVEGFR-1 production by tumor-associated macrophages, whereas HIF-1α specifically regulated VEGF production. We therefore hypothesized that chemical stabilization of HIF-2α using an inhibitor of prolyl hydroxylase domain 3 (an upstream inhibitor of HIF-2α activation) would increase sVEGFR-1 production from GM-CSF-stimulated macrophages. Treatment of macrophages with the prolyl hydroxylase domain 3 inhibitor AKB-6899 stabilized HIF-2α and increased sVEGFR-1 production from GM-CSF-treated macrophages, with no effect on HIF-1α accumulation or VEGF production. Treatment of B16F10 melanoma-bearing mice with GM-CSF and AKB-6899 significantly reduced tumor growth compared with either drug alone. Increased levels of sVEGFR-1 mRNA, but not VEGF mRNA, were detected within the tumors of GM-CSF- and AKB-6899-treated mice, correlating with decreased tumor vascularity. Finally, the antitumor and antiangiogenic effects of AKB-6899 were abrogated when mice were simultaneously treated with a sVEGFR-1 neutralizing Ab. These results demonstrate that AKB-6899 decreases tumor growth and angiogenesis in response to GM-CSF by increasing sVEGFR-1 production from tumor-associated macrophages. Specific activation of HIF-2α can therefore decrease tumor growth and angiogenesis.
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MESH Headings
- Animals
- Antineoplastic Agents/metabolism
- Antineoplastic Agents/therapeutic use
- Basic Helix-Loop-Helix Transcription Factors/metabolism
- Basic Helix-Loop-Helix Transcription Factors/physiology
- Cell Line, Tumor
- Cells, Cultured
- Dioxygenases/antagonists & inhibitors
- Dioxygenases/biosynthesis
- Disease Models, Animal
- Granulocyte-Macrophage Colony-Stimulating Factor/administration & dosage
- Growth Inhibitors/biosynthesis
- Growth Inhibitors/metabolism
- Growth Inhibitors/therapeutic use
- Humans
- Hypoxia-Inducible Factor-Proline Dioxygenases
- Macrophages/immunology
- Macrophages/metabolism
- Macrophages/pathology
- Melanoma, Experimental/immunology
- Melanoma, Experimental/pathology
- Melanoma, Experimental/prevention & control
- Mice
- Mice, Inbred C57BL
- Mice, SCID
- Mice, Transgenic
- Neovascularization, Pathologic/immunology
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/prevention & control
- Protein Stability
- Solubility
- Vascular Endothelial Growth Factor Receptor-1/biosynthesis
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Affiliation(s)
- Julie M. Roda
- The Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Yijie Wang
- The Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Laura A. Sumner
- The Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Gary S. Phillips
- The Center for Biostatistics, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Clay B. Marsh
- The Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210, USA
- The Comprehensive Cancer Center, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Timothy D. Eubank
- The Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210, USA
- The Comprehensive Cancer Center, The Ohio State University College of Medicine, Columbus, OH 43210, USA
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Ong SG, Hausenloy DJ. Hypoxia-inducible factor as a therapeutic target for cardioprotection. Pharmacol Ther 2012; 136:69-81. [PMID: 22800800 DOI: 10.1016/j.pharmthera.2012.07.005] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 06/18/2012] [Indexed: 10/28/2022]
Abstract
Hypoxia inducible factor (HIF) is an oxygen-sensitive transcription factor that enables aerobic organisms to adapt to hypoxia. This is achieved through the transcriptional activation of up to 200 genes, many of which are critical to cell survival. Under conditions of normoxia, the hydroxylation of HIF by prolyl hydroxylase domain-containing (PHD) enzymes targets it for polyubiquitination and proteosomal degradation by the von Hippel-Lindau protein (VHL). However, under hypoxic conditions, PHD activity is inhibited, thereby allowing HIF to accumulate and translocate to the nucleus, where it binds to the hypoxia-responsive element sequences of target gene promoters. Experimental studies suggest that HIF may act as a mediator of ischemic preconditioning, and that the genetic or pharmacological stabilization of HIF under normoxic conditions, may protect the heart against the detrimental effects of acute ischemia-reperfusion injury. The mechanisms underlying the cardioprotective effect of HIF are unclear, but it may be attributed to the transcriptional activation of genes associated with cardioprotection such as erythropoietin, heme oxygenase-1, and inducible nitric oxide synthase or it may be due to reprogramming of cell metabolism. In this review article, we highlight the role of HIF in mediating both adaptive and pathological processes in the heart, as well as focusing on the therapeutic potential of the HIF-signaling pathway as a target for cardioprotection.
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Affiliation(s)
- Sang-Ging Ong
- The Hatter Cardiovascular Institute, University College London Hospital, 67 Chenies Mews, London WC1E 6HX, United Kingdom
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55
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Ouma GO, Jonas RA, Usman MHU, Mohler ER. Targets and delivery methods for therapeutic angiogenesis in peripheral artery disease. Vasc Med 2012; 17:174-92. [PMID: 22496126 PMCID: PMC3760002 DOI: 10.1177/1358863x12438270] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Therapeutic angiogenesis utilizing genetic and cellular modalities in the treatment of arterial obstructive diseases continues to evolve. This is, in part, because the mechanism of vasculogenesis, angiogenesis, and arteriogenesis (the three processes by which the body responds to obstruction of large conduit arteries) is a complex process that is still under investigation. To date, the majority of human trials utilizing molecular, genetic, and cellular modalities for therapeutic angiogenesis in the treatment of peripheral artery disease (PAD) have not shown efficacy. Consequently, the current available knowledge is yet to be translated into novel therapeutic approaches for the treatment of PAD. The aim of this review is to discuss relevant scientific and clinical advances in therapeutic angiogenesis and their potential application in the treatment of ischemic diseases of the peripheral arteries. Additionally, this review article discusses past and recent developments, such as some unconventional approaches that have the potential to be applied as therapeutic targets. The article also includes advances in the delivery of genetic, cellular, and bioactive endothelial growth factors.
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Affiliation(s)
- Geoffrey O Ouma
- Department of Medicine, Cardiovascular Division, Vascular Medicine Section, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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56
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Sun HK, Lee YM, Han KH, Kim HS, Ahn SH, Han SY. Phosphodiesterase inhibitor improves renal tubulointerstitial hypoxia of the diabetic rat kidney. Korean J Intern Med 2012; 27:163-70. [PMID: 22707888 PMCID: PMC3372800 DOI: 10.3904/kjim.2012.27.2.163] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 09/26/2011] [Accepted: 11/04/2011] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND/AIMS Renal hypoxia is involved in the pathogenesis of diabetic nephropathy. Pentoxifyllin (PTX), a nonselective phosphodiesterase inhibitor, is used to attenuate peripheral vascular diseases. To determine whether PTX can improve renal hypoxia, we investigated its effect in the streptozocin (STZ)-induced diabetic kidney. METHODS PTX (40 mg/kg, p.o.) was administered to STZ-induced diabetic rats for 8 weeks. To determine tissue hypoxia, we examined hypoxic inducible factor-1α (HIF-1α), heme oxygenase-1 (HO-1), vascular endothelial growth factor (VEGF), and glucose transporter-1 (GLUT-1) levels. We also tested the effect of PTX on HIF-1α in renal tubule cells. RESULTS PTX reduced the increased protein creatinine ratio in diabetic rats at 8 weeks. HIF-1α, VEGF, and GLUT-1 mRNA expression increased significantly, and the expression of HO-1 also tended to increase in diabetic rats. PTX significantly decreased mRNA expression of HIF-1α and VEGF at 4 and 8 weeks, and decreased HO-1 and GLUT-1 at 4 weeks. The expression of HIF-1α protein was significantly increased at 4 and 8 weeks in tubules in the diabetic rat kidney. PTX tended to decrease HIF-1α protein expression at 8 weeks. To examine whether PTX had a direct effect on renal tubules, normal rat kidney cells were stimulated with CoCl(2) (100 µM), which enhanced HIF-1α mRNA and protein levels under low glucose conditions (5.5 mM). Their expressions were similar even after high glucose (30 mM) treatment. PTX had no effect on HIF-1α expression. CONCLUSIONS PTX attenuates tubular hypoxia in the diabetic kidney.
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Affiliation(s)
- Hui-Kyoung Sun
- Division of Nephrology, Department of Internal Medicine, Ilsan-Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Yun Mi Lee
- Clinical Research Center, Ilsan-Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Kum Hyun Han
- Division of Nephrology, Department of Internal Medicine, Ilsan-Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Han-Seong Kim
- Department of Pathology, Ilsan-Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Seon-Ho Ahn
- Division of Nephrology, Department of Medicine, Wonkwang University College of Medicine, Iksan, Korea
| | - Sang-Youb Han
- Division of Nephrology, Department of Internal Medicine, Ilsan-Paik Hospital, Inje University College of Medicine, Goyang, Korea
- Clinical Research Center, Ilsan-Paik Hospital, Inje University College of Medicine, Goyang, Korea
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57
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Chen RL, Nagel S, Papadakis M, Bishop T, Pollard P, Ratcliffe PJ, Pugh CW, Buchan AM. Roles of individual prolyl-4-hydroxylase isoforms in the first 24 hours following transient focal cerebral ischaemia: insights from genetically modified mice. J Physiol 2012; 590:4079-91. [PMID: 22615432 DOI: 10.1113/jphysiol.2012.232884] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
This study investigated the function of each of the hypoxia inducible factor (HIF) prolyl-4-hydroxylase enzymes (PHD1–3) in the first 24 h following transient focal cerebral ischaemia by using mice with each isoform genetically suppressed. Male, 8- to 12-week old PHD1−/−, PHD2+/− and PHD3−/− mice and their wild-type (WT) littermate were subjected to 45 min of middle cerebral artery occlusion (MCAO). During the experiments, regional cerebral blood flow (rCBF) was recorded by laser Doppler flowmetry. Behaviour was assessed at both 2 h and 24 h after reperfusion with a common neuroscore. Infarct volumes, blood–brain barrier (BBB) disruption, cerebral vascular density, apoptosis, reactive oxygen species (ROS), HIF1α, and glycogen levels were then determined using histological and immunohistochemical techniques. When compared to their WT littermates, PHD2+/− mice had significantly increased cerebral microvascular density and more effective restoration of CBF upon reperfusion. PHD2+/− mice showed significantly better functional outcomes and higher activity rates at both 2 h and 24 h after MCAO, associated with significant fewer apoptotic cells in the penumbra and less BBB disruption; PHD3−/− mice had impaired rCBF upon early reperfusion but comparable functional outcomes; PHD1−/− mice did not show any significant changes following the MCAO. Production of ROS, HIF1α staining and glycogen content in the brain were not different in any comparison. Life-long genetic inhibition of PHD enzymes produces different effects on outcome in the first 24 h after transient cerebral ischaemia. These need to be considered in optimizing therapeutic effects of PHD inhibitors, particularly when isoform specific inhibitors become available.
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Affiliation(s)
- Ruo-Li Chen
- Nuffield Department of Medicine, University of Oxford, John Radcliffe Hospital, Headley Way, Headington, Oxford, OX3 9DU, UK
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58
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Chen C, Zhou C. Hypoxia-Inducible Factor: A New Hope to Counteract Stroke. Transl Stroke Res 2012. [DOI: 10.1007/978-1-4419-9530-8_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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59
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Manalo DJ, Baek JH, Buehler PW, Struble E, Abraham B, Alayash AI. Inactivation of prolyl hydroxylase domain (PHD) protein by epigallocatechin (EGCG) stabilizes hypoxia-inducible factor (HIF-1α) and induces hepcidin (Hamp) in rat kidney. Biochem Biophys Res Commun 2011; 416:421-6. [DOI: 10.1016/j.bbrc.2011.11.085] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 11/16/2011] [Indexed: 10/15/2022]
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Dimethyloxalylglycine stabilizes HIF-1α in cultured human endothelial cells and increases random-pattern skin flap survival in vivo. Plast Reconstr Surg 2011; 128:415-422. [PMID: 21788833 DOI: 10.1097/prs.0b013e31821e6e69] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND The goal of this study was to evaluate in vitro and in vivo the effects of up-regulation of the proangiogenic hypoxia inducible factor (HIF)-1α induced by dimethyloxalylglycine on endothelial cell cultures and on skin flap survival. METHODS Human umbilical vein endothelial cell cultures were exposed to hypoxic conditions, to dimethyloxalylglycine, and to cobalt chloride for up to 24 hours. Expression of HIF-1α and vascular endothelial growth factor (VEGF) in cell culture media was analyzed. In vivo, 20 male Wistar rats were assigned randomly to either the treatment group (dimethyloxalylglycine intraperitoneal injection, n = 10) or the control group (saline intraperitoneal injection, n = 10). A dorsal skin flap was raised in all animals and sutured back into place. Flap survival was evaluated on postoperative day 7 by laser Doppler and digital planimetry. RESULTS In vitro treatment of human umbilical vein endothelial cells during a 24-hour period showed a significant elevation of VEGF expression with dimethyloxalylglycine exposure (92 ± 35 pg/mg total cellular protein) or hypoxia exposure (88 ± 21 pg/mg total cellular protein) compared with controls (23 ± 10 pg/mg total cellular protein) (p < 0.05 for both). In vivo experiments showed a significant decrease of flap necrosis in the treatment group animals versus controls (35.95 ± 5.03 percent versus 44.42 ± 5.18 percent, p < 0.05). The laser Doppler evaluation revealed significantly increased blood flow in the proximal two-thirds of the flap in the treatment group compared with the control group (p < 0.05). CONCLUSION Dimethyloxalylglycine treatment significantly increases VEGF and HIF-1α expression in endothelial cell cultures and enhances skin flap survival in vivo in a rat model.
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61
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Macrophage skewing by Phd2 haplodeficiency prevents ischaemia by inducing arteriogenesis. Nature 2011; 479:122-6. [PMID: 21983962 DOI: 10.1038/nature10507] [Citation(s) in RCA: 232] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 08/23/2011] [Indexed: 01/17/2023]
Abstract
PHD2 serves as an oxygen sensor that rescues blood supply by regulating vessel formation and shape in case of oxygen shortage. However, it is unknown whether PHD2 can influence arteriogenesis. Here we studied the role of PHD2 in collateral artery growth by using hindlimb ischaemia as a model, a process that compensates for the lack of blood flow in case of major arterial occlusion. We show that Phd2 (also known as Egln1) haplodeficient (Phd2(+/-)) mice displayed preformed collateral arteries that preserved limb perfusion and prevented tissue necrosis in ischaemia. Improved arteriogenesis in Phd2(+/-) mice was due to an expansion of tissue-resident, M2-like macrophages and their increased release of arteriogenic factors, leading to enhanced smooth muscle cell (SMC) recruitment and growth. Both chronic and acute deletion of one Phd2 allele in macrophages was sufficient to skew their polarization towards a pro-arteriogenic phenotype. Mechanistically, collateral vessel preconditioning relied on the activation of canonical NF-κB pathway in Phd2(+/-) macrophages. These results unravel how PHD2 regulates arteriogenesis and artery homeostasis by controlling a specific differentiation state in macrophages and suggest new treatment options for ischaemic disorders.
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Huang H, Van de Veire S, Dalal M, Parlier R, Semba RD, Carmeliet P, Vinores SA. Reduced retinal neovascularization, vascular permeability, and apoptosis in ischemic retinopathy in the absence of prolyl hydroxylase-1 due to the prevention of hyperoxia-induced vascular obliteration. Invest Ophthalmol Vis Sci 2011; 52:7565-73. [PMID: 21873682 DOI: 10.1167/iovs.11-8002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
PURPOSE Prolyl hydroxylases (PHDs) are oxygen sensors that stabilize hypoxia-inducible factors (HIFs) to induce proinflammatory, vasopermeability, and proapoptotic factors. These may be potential targets to reduce the complications of ischemic retinopathies. METHODS Oxygen-induced ischemic retinopathy (OIR) was generated as a model for retinopathy of prematurity (ROP) by placing 7-day-old mice in 75% oxygen for 5 days and returning them to the relative hypoxia of room air for 5 days. Neovascularization (NV) and avascular areas were assessed on retinal flat-mounts by image analysis. Blood-retinal barrier breakdown was assessed using ³H-mannitol as a tracer. Apoptosis was detected with TUNEL staining. HIF-1α and VEGF were quantified using Western blot analysis and ELISA. RESULTS PHD1-deficient mice demonstrated reduced hyperoxia-associated vascular obliteration during oxygen-induced ischemic retinopathy. This was associated with subsequent reduced avascularity, vascular leakage, and pathologic NV during the hypoxic phase, which could be accounted for by a reduced expression of HIF-1α and VEGF. Apoptosis in the retina was also reduced in PHD1-depleted mice after 2 days in hyperoxia. CONCLUSIONS PHD1 deficiency is associated with a reduction of ischemia-induced retinal NV. The regulatory mechanism in this model appears to be: PHD1 depletion prevents HIF-1α degradation in hyperoxia, which induces VEGF, thus preventing hyperoxia-related vessel loss. Without a vessel deficiency, there would not be relative hypoxia when the mice are returned to room air and there would be no need to initiate angiogenesis signaling. Blocking PHD1 may be beneficial for ischemic retinopathies and inflammatory and neurodegenerative disorders.
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Affiliation(s)
- Hu Huang
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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Wang ZJ, Kumar R, Banerjee S, Hsu CY. Blood oxygen level-dependent (BOLD) MRI of diabetic nephropathy: preliminary experience. J Magn Reson Imaging 2011; 33:655-60. [PMID: 21563249 DOI: 10.1002/jmri.22501] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE To evaluate the blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) findings in kidneys of patients with diabetic nephropathy. MATERIALS AND METHODS BOLD MRI of the kidneys (1.5 T, multigradient-recalled-echo sequence with 12 echoes) was performed in 20 patients with diabetic nephropathy (moderate to severe chronic kidney disease: n = 14; mild chronic kidney disease: n = 6), and seven healthy volunteers. The medullary and cortical R2* values were compared between patients with diabetic nephropathy and healthy volunteers using Student's t-tests. RESULTS The mean medullary R2* values were lower in patients with diabetic nephropathy compared to healthy volunteers (13.8 ± 2.4 sec(-1) vs. 19.3 ± 1.2 sec(-1), P = 0.0002). The cortical R2* values were not significantly different between the two groups (11.1 ± 0.9 sec(-1) vs. 11.5 ± 0.7 sec(-1), P = 0.7). A multiple logistic regression model using patient age, gender, and degree of chronic kidney disease (none, mild, or moderate to severe) as variables showed that the degree of kidney disease was independently associated with a decrease in medullary R2* values (P = 0.005). CONCLUSION The medullary R2* values were lower in patients with diabetic nephropathy compared to healthy volunteers.
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Affiliation(s)
- Zhen J Wang
- Department of Radiology, University of California San Francisco, San Francisco, California, USA.
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Miyata T, Kikuchi K, Kiyomoto H, van Ypersele de Strihou C. New era for drug discovery and development in renal disease. Nat Rev Nephrol 2011; 7:469-77. [PMID: 21727928 DOI: 10.1038/nrneph.2011.84] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Drug discovery and development is a lengthy and expensive process. Testing new agents in humans at an early stage could reduce the time and costs involved in identifying drugs that are likely to succeed in clinical studies. New guidance has outlined the concept of exploratory clinical trials, which provide important information on a drug's distribution as well as its physiological and pharmacological effects in humans. This strategy reduces the need for preclinical testing by limiting the dose and duration of exposure to a new drug in humans to below those required by the traditional testing of investigational new drugs. Exploratory, first-in-man studies should provide insights into human physiology and pharmacology, identify therapeutic targets relevant to disease and increase our knowledge of a drug's characteristics. Implementation of a new drug also requires the development of useful biomarkers of disease and of the drug's efficacy, as well as sensitive molecular imaging techniques. In this Review, we outline the benefits of exploratory clinical trials, especially in academia, and provide an overview of the experimental tools necessary for rational drug discovery and development.
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Affiliation(s)
- Toshio Miyata
- United Centers for Advanced Research and Translational Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-Machi, Aoba-ku, Sendai 980-8575, Japan
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Erythropoietin: recent developments in the treatment of spinal cord injury. Neurol Res Int 2011; 2011:453179. [PMID: 21766022 PMCID: PMC3135044 DOI: 10.1155/2011/453179] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 05/09/2011] [Indexed: 01/10/2023] Open
Abstract
Erythropoietin (EPO), originally identified for its critical function in regulating production and survival of erythrocytes, is a member of the type 1 cytokine superfamily. Recent studies have shown that EPO has cytoprotective effects in a wide variety of cells and tissues. Here is presented the analysis of EPO effects on spinal cord injury (SCI), considering both animal experiments concerning to mechanisms of neurodegeneration in SCI and EPO as a neuroprotective agent, and some evidences coming from ongoing clinical trials. The evidences underling that EPO could be a promising therapeutic agent in a variety of neurological insults, including trauma, are mounting. In particular, it is highlighted that administration of EPO or other recently generated EPO analogues such as asialo-EPO and carbamylated-EPO demonstrate interesting preclinical and clinical characteristics, rendering the evaluation of these tissue-protective agents imperative in human clinical trials. Moreover the demonstration of rhEPO and its analogues' broad neuroprotective effects in animal models of cord lesion and in human trial like stroke, should encourage scientists and clinicians to design clinical trials assessing the efficacy of these pharmacological compounds on SCI.
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66
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Baek JH, Reiter CEN, Manalo DJ, Buehler PW, Hider RC, Alayash AI. Induction of hypoxia inducible factor (HIF-1α) in rat kidneys by iron chelation with the hydroxypyridinone, CP94. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:262-8. [PMID: 21558026 DOI: 10.1016/j.bbagrm.2011.04.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 04/19/2011] [Accepted: 04/22/2011] [Indexed: 11/19/2022]
Abstract
Hypoxia inducible factor (HIF-1α) is a master regulator of tissue adaptive responses to hypoxia whose stability is controlled by an iron containing prolyl hydroxylase domain (PHD) protein. A catalytic redox cycle in the PHD's iron center that results in the formation of a ferryl (Fe(+4)) intermediate has been reported to be responsible for the hydroxylation and subsequent degradation of HIF-1α under normoxia. We show that induction of HIF-1α in rat kidneys can be achieved by iron reduction by the hydroxypyridin-4 one (CP94), an iron chelator administered intraperitoneally in rats. The extent of HIF protein stabilization as well as the expression of HIF target genes, including erythropoietin (EPO), in kidney tissues was comparable to those induced by known inhibitors of the PHD enzyme, such as desferrioxamine (DFO) and cobalt chloride (CoCl(2)). In human kidney cells and in vitro PHD activity assay, we were able to show that the HIF-1α protein can be stabilized by addition of CP94. This appears to inactivate PHD; and thus prevents the hydroxylation of HIF-1α. In conclusion, we have identified the inhibition of iron-binding pocket of PHD as an underlying mechanism of HIF induction in vivo and in vitro by a bidentate hydroxypyridinone.
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Affiliation(s)
- Jin Hyen Baek
- Laboratory of Biochemistry and Vascular Biology, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA
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Belaidi E, Beguin PC, Levy P, Ribuot C, Godin-Ribuot D. Delayed myocardial preconditioning induced by cobalt chloride in the rat: HIF-1α and iNOS involvement. Fundam Clin Pharmacol 2011; 26:454-62. [DOI: 10.1111/j.1472-8206.2011.00940.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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68
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Rose NR, McDonough MA, King ONF, Kawamura A, Schofield CJ. Inhibition of 2-oxoglutarate dependent oxygenases. Chem Soc Rev 2011; 40:4364-97. [PMID: 21390379 DOI: 10.1039/c0cs00203h] [Citation(s) in RCA: 306] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
2-Oxoglutarate (2OG) dependent oxygenases are ubiquitous iron enzymes that couple substrate oxidation to the conversion of 2OG to succinate and carbon dioxide. In humans their roles include collagen biosynthesis, fatty acid metabolism, DNA repair, RNA and chromatin modifications, and hypoxic sensing. Commercial applications of 2OG oxygenase inhibitors began with plant growth retardants, and now extend to a clinically used pharmaceutical compound for cardioprotection. Several 2OG oxygenases are now being targeted for therapeutic intervention for diseases including anaemia, inflammation and cancer. In this critical review, we describe studies on the inhibition of 2OG oxygenases, focusing on small molecules, and discuss the potential of 2OG oxygenases as therapeutic targets (295 references).
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Affiliation(s)
- Nathan R Rose
- Department of Chemistry and the Oxford Centre for Integrative Systems Biology, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
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Gan Y, Herzog EL, Gomer RH. Pirfenidone treatment of idiopathic pulmonary fibrosis. Ther Clin Risk Manag 2011; 7:39-47. [PMID: 21339942 PMCID: PMC3039013 DOI: 10.2147/tcrm.s12209] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Indexed: 12/29/2022] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a discrete clinicopathologic entity defined by the presence of usual interstitial pneumonia on high-resolution CT scan and/or open lung biopsy and the absence of an alternate diagnosis or exposure explaining these findings. There are currently no FDA-approved therapies available to treat this disease, and the 5-year mortality is ∼80%. The pyridone derivative pirfenidone has been studied extensively as a possible therapeutic agent for use in this deadly disease. This review will present the unique clinical features and management issues encountered by physicians caring for IPF patients, including the poor response to conventional therapy. The biochemistry and preclinical efficacy of pirfenidone will be discussed along with a comprehensive review of the clinical efficacy, safety, and side effects and patient-centered foci such as quality of life and tolerability. It is hoped that this information will lend insight into the complex issues surrounding the use of pirfenidone in IPF and lead to further investigation of this agent as a possible therapy in this devastating disease.
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Affiliation(s)
- Ye Gan
- Department of Medicine, Central South University, Changsha, Hunan, China
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Alili L, Sack M, Karakoti AS, Teuber S, Puschmann K, Hirst SM, Reilly CM, Zanger K, Stahl W, Das S, Seal S, Brenneisen P. Combined cytotoxic and anti-invasive properties of redox-active nanoparticles in tumor-stroma interactions. Biomaterials 2011; 32:2918-29. [PMID: 21269688 DOI: 10.1016/j.biomaterials.2010.12.056] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Accepted: 12/31/2010] [Indexed: 12/27/2022]
Abstract
Tumor-stroma interaction plays an important role in tumor progression. Myofibroblasts, pivotal for tumor progression, populate the microecosystem of reactive stroma. The formation of myofibroblasts is mediated by tumor derived transforming growth factor β1 (TGFβ1) which initiates a reactive oxygen species cell type dependent expression of alpha-smooth muscle actin, a biomarker for myofibroblastic cells. Myofibroblasts express and secrete proinvasive factors significantly increasing the invasive capacity of tumor cells via paracrine mechanisms. Although antioxidants prevent myofibroblast formation, the same antioxidants increase the aggressive behavior of the tumor cells. In this study, the question was addressed of whether redox-active polymer-coated cerium oxide nanoparticles (CNP, nanoceria) affect myofibroblast formation, cell toxicity, and tumor invasion. Herein, nanoceria downregulate both the expression of alpha-smooth muscle actin positive myofibroblastic cells and the invasion of tumor cells. Furthermore, concentrations of nanoceria being non-toxic for normal (stromal) cells show a cytotoxic effect on squamous tumor cells. The treatment with redox-active CNP may form the basis for protection of stromal cells from the dominating influence of tumor cells in tumor-stroma interaction, thus being a promising strategy for chemoprevention of tumor invasion.
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Affiliation(s)
- Lirija Alili
- Institute of Biochemistry & Molecular Biology I, Medical Faculty, Heinrich-Heine-University, 40225 Duesseldorf, Germany
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Chronic inhibition of hypoxia-inducible factor prolyl 4-hydroxylase improves ventricular performance, remodeling, and vascularity after myocardial infarction in the rat. J Cardiovasc Pharmacol 2010; 56:147-55. [PMID: 20714241 DOI: 10.1097/fjc.0b013e3181e2bfef] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Hypoxia inducible factors (HIFs) are transcription factors that are regulated by HIF-prolyl 4-hydroxylases (PHDs) in response to changes in oxygen tension. Once activated, HIFs play an important role in angiogenesis, erythropoiesis, proliferation, cell survival, inflammation, and energy metabolism. We hypothesized that GSK360A, a novel orally active HIF-PHD inhibitor, could facilitate local and systemic HIF-1 alpha signaling and protect the failing heart after myocardial infarction (MI). METHODS AND RESULTS GSK360A is a potent (nanomolar) inhibitor of HIF-PHDs (PHD1>PHD2 = PHD3) capable of activating the HIF-1 alpha pathway in a variety of cell types including neonatal rat ventricular myocytes and H9C2 cells. Male rats treated orally with GSK360A (30 mg x kg x d) had a sustained elevation in circulating levels of erythropoietin and hemoglobin and increased hemoxygenase-1 expression in the heart and skeletal muscle. In a rat model of established heart failure with systolic dysfunction induced by ligation of left anterior descending coronary artery, chronic treatment with GSK360A for 28 days prevented the progressive reduction in ejection fraction, ventricular dilation, and increased lung weight, which were observed in the vehicle-treated animals, for up to 3 months. In addition, the microvascular density in the periinfarct region was increased (>2-fold) in GSK360A-treated animals. Treatment was well tolerated (survival was 89% in the GSK360A group vs. 82% in the placebo group). CONCLUSIONS Chronic post-myocardial infarction treatment with a selective HIF PHD inhibitor (GSK360A) exerts systemic and local effects by stabilizing HIF-1 alpha signaling and improves long-term ventricular function, remodeling, and vascularity in a model of established ventricular dysfunction. These results suggest that HIF-PHD inhibitors may be suitable for the treatment of post-MI remodeling and heart failure.
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Tambuwala MM, Cummins EP, Lenihan CR, Kiss J, Stauch M, Scholz CC, Fraisl P, Lasitschka F, Mollenhauer M, Saunders SP, Maxwell PH, Carmeliet P, Fallon PG, Schneider M, Taylor CT. Loss of prolyl hydroxylase-1 protects against colitis through reduced epithelial cell apoptosis and increased barrier function. Gastroenterology 2010; 139:2093-101. [PMID: 20600011 DOI: 10.1053/j.gastro.2010.06.068] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 05/27/2010] [Accepted: 06/21/2010] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Hypoxia inducible factor (HIF) prolyl hydroxylase inhibitors are protective in mouse models of inflammatory bowel disease (IBD). Here, we investigated the therapeutic target(s) and mechanism(s) involved. METHODS The effect of genetic deletion of individual HIF-prolyl hydroxylase (PHD) enzymes on the development of dextran sulphate sodium (DSS)-induced colitis was examined in mice. RESULTS PHD1(-/-), but not PHD2(+/-) or PHD3(-/-), mice were less susceptible to the development of colitis than wild-type controls as determined by weight loss, disease activity, colon histology, neutrophil infiltration, and cytokine expression. Reduced susceptibility of PHD1(-/-) mice to colitis was associated with increased density of colonic epithelial cells relative to wild-type controls, which was because of decreased levels of apoptosis that resulted in enhanced epithelial barrier function. Furthermore, with the use of cultured epithelial cells it was confirmed that hydroxylase inhibition reversed DSS-induced apoptosis and barrier dysfunction. Finally, PHD1 levels were increased with disease severity in intestinal tissue from patients with IBD and in colonic tissues from DSS-treated mice. CONCLUSIONS These results imply a role for PHD1 as a positive regulator of intestinal epithelial cell apoptosis in the inflamed colon. Genetic loss of PHD1 is protective against colitis through decreased epithelial cell apoptosis and consequent enhancement of intestinal epithelial barrier function. Thus, targeted PHD1 inhibition may represent a new therapeutic approach in IBD.
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Miyata T, Takizawa S, van Ypersele de Strihou C. Hypoxia. 1. Intracellular sensors for oxygen and oxidative stress: novel therapeutic targets. Am J Physiol Cell Physiol 2010; 300:C226-31. [PMID: 20980551 DOI: 10.1152/ajpcell.00430.2010] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A variety of human disorders, e.g., ischemic heart disease, stroke, kidney disease, eventually share the deleterious consequences of a common, hypoxic and oxidative stress pathway. In this review, we utilize recent information on the cellular defense mechanisms against hypoxia and oxidative stress with the hope to propose new therapeutic tools. The hypoxia-inducible factor (HIF) is a key player as it activates a broad range of genes protecting cells against hypoxia. Its level is determined by its degradation rate by intracellular oxygen sensors prolyl hydroxylases (PHDs). There are three different PHD isoforms (PHD1-3). Small molecule PHD inhibitors improve hypoxic injury in experimental animals but, unfortunately, may induce adverse effects associated with PHD2 inhibition, e.g., angiogenesis. As yet, no inhibitor specific for a distinct PHD isoform is currently available. Still, the specific disruption of the PHD1 gene is known to induce hypoxic tolerance, without angiogenesis and erythrocytosis, by reprogramming basal oxygen metabolism with an attendant decreased oxidative stress in hypoxic mitochondria. A specific PHD1 inhibitor might therefore offer a novel therapy against hypoxia. The nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) regulates the basal and inducible expression of numerous antioxidant stress genes. Disruption of its gene exacerbates oxidative tissue injury. Nrf2 activity is modulated by Kelch-like ECH-associated protein 1 (Keap1), an intracellular sensor for oxidative stress. Inhibitors of Keap 1 may prove therapeutic against oxidative tissue injury.
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Affiliation(s)
- Toshio Miyata
- United Centers for Advanced Research and Translational Medicine, Tohoku University School of Medicine, 2-1 Seiryo-Machi, Aoba-ku, Sendai, 980-8575, Japan.
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Weinreb O, Amit T, Mandel S, Kupershmidt L, Youdim MBH. Neuroprotective multifunctional iron chelators: from redox-sensitive process to novel therapeutic opportunities. Antioxid Redox Signal 2010; 13:919-49. [PMID: 20095867 DOI: 10.1089/ars.2009.2929] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Accumulating evidence suggests that many cytotoxic signals occurring in the neurodegenerative brain can initiate neuronal death processes, including oxidative stress, inflammation, and accumulation of iron at the sites of the neuronal deterioration. Neuroprotection by iron chelators has been widely recognized with respect to their ability to prevent hydroxyl radical formation in the Fenton reaction by sequestering redox-active iron. An additional neuroprotective mechanism of iron chelators is associated with their ability to upregulate or stabilize the transcriptional activator, hypoxia-inducible factor-1alpha (HIF-1alpha). HIF-1alpha stability within the cells is under the control of a class of iron-dependent and oxygen-sensor enzymes, HIF prolyl-4-hydroxylases (PHDs) that target HIF-1alpha for degradation. Thus, an emerging novel target for neuroprotection is associated with the HIF system to promote stabilization of HIF-1alpha and increase transcription of HIF-1-related survival genes, which have been reported to be regulated in patient's brains afflicted with diverse neurodegenerative diseases. In accordance, a new potential therapeutic strategy for neurodegenerative diseases is explored, by which iron chelators would inhibit PHDs, target the HIF-1-signaling pathway and ultimately activate HIF-1-dependent neuroprotective genes. This review discusses two interrelated approaches concerning therapy targets in neurodegeneration, sharing in common the implementation of iron chelation activity: antioxidation and HIF-1-pathway activation.
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Affiliation(s)
- Orly Weinreb
- Eve Topf Centers of Excellence for Neurodegenerative Diseases Research and Department of Pharmacology, Rappaport Family Research Institute, Technion-Faculty of Medicine, Haifa, Israel.
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Smirnova NA, Rakhman I, Moroz N, Basso M, Payappilly J, Kazakov S, Hernandez-Guzman F, Gaisina IN, Kozikowski AP, Ratan RR, Gazaryan IG. Utilization of an in vivo reporter for high throughput identification of branched small molecule regulators of hypoxic adaptation. ACTA ACUST UNITED AC 2010; 17:380-91. [PMID: 20416509 DOI: 10.1016/j.chembiol.2010.03.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/26/2010] [Accepted: 03/09/2010] [Indexed: 01/03/2023]
Abstract
Small molecules inhibiting hypoxia inducible factor (HIF) prolyl hydroxylases (PHDs) are the focus of drug development efforts directed toward the treatment of ischemia and metabolic imbalance. A cell-based reporter produced by fusing HIF-1 alpha oxygen degradable domain (ODD) to luciferase was shown to work as a capture assay monitoring stability of the overexpressed luciferase-labeled HIF PHD substrate under conditions more physiological than in vitro test tubes. High throughput screening identified novel catechol and oxyquinoline pharmacophores with a "branching motif" immediately adjacent to a Fe-binding motif that fits selectively into the HIF PHD active site in in silico models. In accord with their structure-activity relationship in the primary screen, the best "hits" stabilize HIF1 alpha, upregulate known HIF target genes in a human neuronal line, and exert neuroprotective effects in established model of oxidative stress in cortical neurons.
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Affiliation(s)
- Natalya A Smirnova
- Burke Medical Research Institute, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, 785 Mamaroneck Ave, White Plains, NY 10605, USA
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76
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Complex role of the HIF system in cardiovascular biology. J Mol Med (Berl) 2010; 88:1101-11. [DOI: 10.1007/s00109-010-0646-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Revised: 05/17/2010] [Accepted: 06/11/2010] [Indexed: 12/18/2022]
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Nagel S, Talbot NP, Mecinović J, Smith TG, Buchan AM, Schofield CJ. Therapeutic manipulation of the HIF hydroxylases. Antioxid Redox Signal 2010; 12:481-501. [PMID: 19754349 DOI: 10.1089/ars.2009.2711] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The hypoxia-inducible factor (HIF) family of transcription factors is responsible for coordinating the cellular response to low oxygen levels in animals. By regulating the expression of a large array of target genes during hypoxia, these proteins also direct adaptive changes in the hematopoietic, cardiovascular, and respiratory systems. They also play roles in pathological processes, including tumorogenesis. In recent years, several oxygenases have been identified as key molecular oxygen sensors within the HIF system. The HIF hydroxylases regulate the stability and transcriptional activity of the HIF-alpha subunit by catalyzing hydroxylation of specific proline and asparaginyl residues, respectively. They require oxygen and 2-oxoglutarate (2OG) as co-substrates, and depend upon non-heme ferrous iron (Fe(II)) as a cofactor. This article summarizes current understanding of the biochemistry of the HIF hydroxylases, identifies targets for their pharmacological manipulation, and discusses their potential in the therapeutic manipulation of the HIF system.
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Affiliation(s)
- Simon Nagel
- Acute Stroke Programme, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Headington, Oxford, United Kingdom
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Abstract
Chronic hypoxia induces sequential abnormalities in oxygen metabolism (for example, oxidative stress, nitrosative stress, advanced glycation, carbonyl stress, endoplasmic reticulum stress) in the kidneys of individuals with diabetes. Identification of these abnormalities improves our understanding of therapeutic benefits that can be achieved with antihypertensive agents, the control of hyperglycemia and/or hyperinsulinemia and the dietary correction of obesity. Key to the body's defense against hypoxia is hypoxia-inducible factor, the activity of which is modulated by prolyl hydroxylases (PHDs)-oxygen sensors whose inhibition may prove therapeutic. Renal benefits of small-molecule PHD inhibitors have been documented in several animal models, including those of diabetic nephropathy. Three different PHD isoforms have been identified (PHD1, PHD2 and PHD3) and their respective roles have been delineated in knockout mouse studies. Unfortunately, none of the current inhibitors is specific for a distinct PHD isoform. Nonspecific inhibition of PHDs might induce adverse effects, such as those associated with PHD2 inhibition. Specific disruption of PHD1 induces hypoxic tolerance, without angiogenesis and erythrocytosis, through the reprogramming of basal oxygen metabolism and decreased generation of oxidative stress in hypoxic mitochondria. A specific PHD1 inhibitor might, therefore, offer a novel therapy for abnormal oxygen metabolism not only in the diabetic kidney, but also in other diseases for which hypoxia is a final, common pathway.
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Takeda K, Ichiki T, Narabayashi E, Inanaga K, Miyazaki R, Hashimoto T, Matsuura H, Ikeda J, Miyata T, Sunagawa K. Inhibition of Prolyl Hydroxylase Domain-Containing Protein Suppressed Lipopolysaccharide-Induced TNF-α Expression. Arterioscler Thromb Vasc Biol 2009; 29:2132-7. [DOI: 10.1161/atvbaha.109.196071] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Kotaro Takeda
- From the Departments of Advanced Therapeutics for Cardiovascular Diseases (K.T., T.I., K.S.) and Cardiovascular Medicine (E.N., K.I., R.M., T.H., H.M., J.I., K.S.), Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and the Center for Translational and Advanced Research (T.M.), Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Toshihiro Ichiki
- From the Departments of Advanced Therapeutics for Cardiovascular Diseases (K.T., T.I., K.S.) and Cardiovascular Medicine (E.N., K.I., R.M., T.H., H.M., J.I., K.S.), Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and the Center for Translational and Advanced Research (T.M.), Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Eriko Narabayashi
- From the Departments of Advanced Therapeutics for Cardiovascular Diseases (K.T., T.I., K.S.) and Cardiovascular Medicine (E.N., K.I., R.M., T.H., H.M., J.I., K.S.), Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and the Center for Translational and Advanced Research (T.M.), Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Keita Inanaga
- From the Departments of Advanced Therapeutics for Cardiovascular Diseases (K.T., T.I., K.S.) and Cardiovascular Medicine (E.N., K.I., R.M., T.H., H.M., J.I., K.S.), Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and the Center for Translational and Advanced Research (T.M.), Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Ryohei Miyazaki
- From the Departments of Advanced Therapeutics for Cardiovascular Diseases (K.T., T.I., K.S.) and Cardiovascular Medicine (E.N., K.I., R.M., T.H., H.M., J.I., K.S.), Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and the Center for Translational and Advanced Research (T.M.), Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Toru Hashimoto
- From the Departments of Advanced Therapeutics for Cardiovascular Diseases (K.T., T.I., K.S.) and Cardiovascular Medicine (E.N., K.I., R.M., T.H., H.M., J.I., K.S.), Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and the Center for Translational and Advanced Research (T.M.), Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Hirohide Matsuura
- From the Departments of Advanced Therapeutics for Cardiovascular Diseases (K.T., T.I., K.S.) and Cardiovascular Medicine (E.N., K.I., R.M., T.H., H.M., J.I., K.S.), Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and the Center for Translational and Advanced Research (T.M.), Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Jiro Ikeda
- From the Departments of Advanced Therapeutics for Cardiovascular Diseases (K.T., T.I., K.S.) and Cardiovascular Medicine (E.N., K.I., R.M., T.H., H.M., J.I., K.S.), Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and the Center for Translational and Advanced Research (T.M.), Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Toshio Miyata
- From the Departments of Advanced Therapeutics for Cardiovascular Diseases (K.T., T.I., K.S.) and Cardiovascular Medicine (E.N., K.I., R.M., T.H., H.M., J.I., K.S.), Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and the Center for Translational and Advanced Research (T.M.), Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Kenji Sunagawa
- From the Departments of Advanced Therapeutics for Cardiovascular Diseases (K.T., T.I., K.S.) and Cardiovascular Medicine (E.N., K.I., R.M., T.H., H.M., J.I., K.S.), Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and the Center for Translational and Advanced Research (T.M.), Tohoku University Graduate School of Medicine, Miyagi, Japan
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Branching morphogenesis and antiangiogenesis candidates: tip cells lead the way. Nat Rev Clin Oncol 2009; 6:315-26. [DOI: 10.1038/nrclinonc.2009.64] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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81
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Tanaka T, Nangaku M. Drug discovery for overcoming chronic kidney disease (CKD): prolyl-hydroxylase inhibitors to activate hypoxia-inducible factor (HIF) as a novel therapeutic approach in CKD. J Pharmacol Sci 2009; 109:24-31. [PMID: 19151537 DOI: 10.1254/jphs.08r09fm] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Hypoxia-inducible factor (HIF) is a heterodimeric transcription factor composed of an oxygen-dependent alpha-subunit and constitutively expressed beta subunit, which plays a central role in cellular adaptation to hypoxia by transcriptionally upregulating its target genes involved in angiogenesis, erythropoiesis, glycolysis, and so on. Recent studies demonstrated that hypoxia in the tubulointerstitium is involved in the pathology of progressive renal diseases and that HIF, which is activated in experimental kidney diseases, may serve to protect tubulointerstitium from the ischemic insult. The expression of HIF alpha-chains is post-translationally regulated and hydroxylation at one or two of the conserved proline residues by prolyl-hydroxylase domains (PHDs) is a critical step for the oxygen-dependent recruitment of the von Hippel-Lindau gene product (pVHL), a recognition component of the E3 ubiquitin ligase complex, and degradation of HIF-alpha. Conversely, modalities to inhibit the enzymatic activities of PHDs have been shown to activate HIF irrespective of oxygenation status and are regarded as candidate targets of pharmacological approaches against chronic kidney diseases characterized by hypoxia.
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Affiliation(s)
- Tetsuhiro Tanaka
- Division of Nephrology and Endocrinology, University of Tokyo Hospital and School of Medicine, Tokyo, Japan
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Schultz K, Murthy V, Tatro JB, Beasley D. Prolyl hydroxylase 2 deficiency limits proliferation of vascular smooth muscle cells by hypoxia-inducible factor-1{alpha}-dependent mechanisms. Am J Physiol Lung Cell Mol Physiol 2009; 296:L921-7. [PMID: 19304911 DOI: 10.1152/ajplung.90393.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Arterial O(2) levels are thought to modulate vascular smooth muscle cell (VSMC) proliferation and vascular remodeling, but the mechanisms involved are poorly understood. Here, we tested the hypothesis that PHD2, a prolyl hydroxylase domain (PHD)-containing O(2) sensor, modulates growth factor-induced proliferative responses of human pulmonary artery SMC (HPASMC). We found that both PHD1 and PHD2 were robustly expressed by HPASMC, and inhibiting prolyl hydroxylase activity pharmacologically by using the nonselective dioxygenase inhibitor dimethyloxalylglycine (DMOG) inhibited proliferation and cyclin A expression induced by PDGF-AB or FGF-2. Specific knockdown of PHD2 using small interfering RNAs had similar effects. The inhibitory effects of DMOG and PHD2 knockdown on proliferation and cyclin A expression were seen under both normoxic (20% O(2)) and moderately hypoxic (5% O(2)) conditions, and PHD2 expression was not affected by O(2) level nor by stimulation with PDGF or FGF-2, indicating that the proproliferative influence of PHD2 does not involve alterations of its expression. Knockdown of PHD2 increased hypoxia-inducible factor (HIF)-1alpha expression, as expected, but we also found that HIF-1alpha knockdown abolished the inhibitory effect of PHD2 knockdown on PDGF-induced cyclin A expression. Therefore, we conclude that PHD2 promotes growth factor-induced responses of human VSMC, acting by HIF-1alpha-dependent mechanisms. Given the role of PHD2 as an oxygen sensor in mammalian cells, these results raise the possibility that PHD2 links VSMC proliferation to O(2) availability.
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Affiliation(s)
- Kelly Schultz
- Molecular Cardiology Research Institute, Department of Medicine, Tufts Medical Center, Boston, Massachusetts, USA
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83
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Hypoxia-inducible factor 1 and related gene products in anaesthetic-induced preconditioning. Eur J Anaesthesiol 2009; 26:201-6. [DOI: 10.1097/eja.0b013e3283212cbb] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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84
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Oliver KM, Taylor CT, Cummins EP. Hypoxia. Regulation of NFkappaB signalling during inflammation: the role of hydroxylases. Arthritis Res Ther 2009; 11:215. [PMID: 19291263 PMCID: PMC2688226 DOI: 10.1186/ar2575] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
NFκB is a master regulator of innate immunity and inflammatory signalling. Microenvironmental hypoxia has long been identified as being coincident with chronic inflammation. The contribution of microenvironmental hypoxia to NFκB-induced inflammation has more recently been appreciated. Identification of the co-regulation of NFκB and hypoxia inducible factor (HIF) pathways by 2-oxo-glutarate-dependent hydroxylase family members has highlighted an intimate relationship between NFκB inflammatory signalling and HIF-mediated hypoxic signalling pathways. Adding another layer of complexity to our understanding of the role of NFκB inflammatory signalling by hypoxia is the recent recognition of the contribution of basal NFκB activity to HIF-1α transcription. This observation implicates an important and previously unappreciated role for NFκB in inflammatory disease where HIF-1α is activated. The present review will discuss recent literature pertaining to the regulation of NFκB inflammatory signalling by hypoxia and some of the inflammatory diseases where this may play an important role. Furthermore, we will discuss the potential for prolylhydroxylase inhibitors in inflammatory disease.
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Affiliation(s)
- Kathryn M Oliver
- School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
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85
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Mazzone M, Dettori D, de Oliveira RL, Loges S, Schmidt T, Jonckx B, Tian YM, Lanahan AA, Pollard P, de Almodovar CR, De Smet F, Vinckier S, Aragonés J, Debackere K, Luttun A, Wyns S, Jordan B, Pisacane A, Gallez B, Lampugnani MG, Dejana E, Simons M, Ratcliffe P, Maxwell P, Carmeliet P. Heterozygous deficiency of PHD2 restores tumor oxygenation and inhibits metastasis via endothelial normalization. Cell 2009; 136:839-851. [PMID: 19217150 DOI: 10.1016/j.cell.2009.01.020] [Citation(s) in RCA: 594] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 12/01/2008] [Accepted: 01/15/2009] [Indexed: 01/03/2023]
Abstract
A key function of blood vessels, to supply oxygen, is impaired in tumors because of abnormalities in their endothelial lining. PHD proteins serve as oxygen sensors and may regulate oxygen delivery. We therefore studied the role of endothelial PHD2 in vessel shaping by implanting tumors in PHD2(+/-) mice. Haplodeficiency of PHD2 did not affect tumor vessel density or lumen size, but normalized the endothelial lining and vessel maturation. This resulted in improved tumor perfusion and oxygenation and inhibited tumor cell invasion, intravasation, and metastasis. Haplodeficiency of PHD2 redirected the specification of endothelial tip cells to a more quiescent cell type, lacking filopodia and arrayed in a phalanx formation. This transition relied on HIF-driven upregulation of (soluble) VEGFR-1 and VE-cadherin. Thus, decreased activity of an oxygen sensor in hypoxic conditions prompts endothelial cells to readjust their shape and phenotype to restore oxygen supply. Inhibition of PHD2 may offer alternative therapeutic opportunities for anticancer therapy.
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Affiliation(s)
- Massimiliano Mazzone
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Daniela Dettori
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium.,Laboratory of Cancer Genetics, Institute for Cancer Research and Treatment, University of Turin Medical School, 10060 Candiolo, Turin, Italy
| | - Rodrigo Leite de Oliveira
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Sonja Loges
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Thomas Schmidt
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Bart Jonckx
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Ya-Min Tian
- The Henry Wellcome Building of Genomic Medicine, Oxford OX3 7BN, UK
| | | | - Patrick Pollard
- The Henry Wellcome Building of Genomic Medicine, Oxford OX3 7BN, UK
| | - Carmen Ruiz de Almodovar
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Frederik De Smet
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Stefan Vinckier
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Julián Aragonés
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Koen Debackere
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Aernout Luttun
- Center for Molecular and Vascular Biology, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Sabine Wyns
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Benedicte Jordan
- Biomedical Magnetic Resonance Unit, Medicinal Chemistry and Radiopharmacy U.C. Louvain, 1000 Brussels, Belgium
| | - Alberto Pisacane
- Unit of Pathological Anatomy, Institute for Cancer Research and Treatment, 10060 Candiolo, Turin, Italy
| | - Bernard Gallez
- Biomedical Magnetic Resonance Unit, Medicinal Chemistry and Radiopharmacy U.C. Louvain, 1000 Brussels, Belgium
| | - Maria Grazia Lampugnani
- Vascular Biology Unit, Italian Foundation for Cancer Research Institute of Molecular Oncology, 20139 Milan, Italy
| | - Elisabetta Dejana
- Vascular Biology Unit, Italian Foundation for Cancer Research Institute of Molecular Oncology, 20139 Milan, Italy
| | - Michael Simons
- Cardiovascular Medicine, Yale University, New Haven, CT 06510, USA
| | - Peter Ratcliffe
- The Henry Wellcome Building of Genomic Medicine, Oxford OX3 7BN, UK
| | - Patrick Maxwell
- Rayne Institute, University College London, London WC1E 6JJ, UK
| | - Peter Carmeliet
- Vesalius Research Center, VIB-Vlaams Instituut voor Biotechnologie, 3000 Leuven, Belgium.,Vesalius Research Center, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
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86
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Miyata T, van Ypersele de Strihou C. Translation of basic science into clinical medicine: novel targets for diabetic nephropathy. Nephrol Dial Transplant 2009; 24:1373-7. [PMID: 19211649 DOI: 10.1093/ndt/gfp028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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87
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Inhibition of oxygen sensors as a therapeutic strategy for ischaemic and inflammatory disease. Nat Rev Drug Discov 2009; 8:139-52. [PMID: 19165233 DOI: 10.1038/nrd2761] [Citation(s) in RCA: 273] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cells in the human body need oxygen to function and survive, and severe deprivation of oxygen, as occurs in ischaemic heart disease and stroke, is a major cause of mortality. Nevertheless, other organisms, such as the fossorial mole rat or diving seals, have acquired the ability to survive in conditions of limited oxygen supply. Hypoxia tolerance also allows the heart to survive chronic oxygen shortage, and ischaemic preconditioning protects tissues against lethal hypoxia. The recent discovery of a new family of oxygen sensors--including prolyl hydroxylase domain-containing proteins 1-3 (PHD1-3)--has yielded exciting novel insights into how cells sense oxygen and keep oxygen supply and consumption in balance. Advances in understanding of the role of these oxygen sensors in hypoxia tolerance, ischaemic preconditioning and inflammation are creating new opportunities for pharmacological interventions for ischaemic and inflammatory diseases.
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88
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Abstract
Strategies to alter angiogenesis have been successfully translated from the bench to bedside. With an estimated number of more than 500 million patients worldwide potentially benefiting from it, it is a prime example of targeted therapy that is increasingly changing the face of clinical medicine. Most efforts to stimulate or inhibit angiogenesis in the past were focused on the key angiogenic factor vascular endothelial growth factor (VEGF), resulting in the approval by the Food and Drug Administration of several drugs for the treatment of cancer and ocular disease. However, mounting clinical evidence reveals that inhibition of VEGF causes resistance and class-specific side effects, while therapeutic angiogenesis by delivering VEGF protein is more challenging than anticipated in human patients. Hence, alternatives are needed, and modulation of oxygen-sensitive enzymes (prolyl hydroxylase domain proteins) and of hypoxia induced transcription factors has recently emerged as a potential novel strategy to treat cancer and ischemic diseases. Furthermore, placental growth factor is a disease-specific angiogenic target, whose inhibition reduces cancer growth without causing major side effects, while its delivery induces revascularization of ischemic tissues. In this review, we summarize recent developments and discuss questions that arise in the exciting, rapidly developing field of angiogenic medicine, including a brief description of its possible implications in neurodegenerative diseases.
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Affiliation(s)
- S Loges
- Vesalius Research Center, KU Leuven, Leuven, Belgium
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89
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Sirén AL, Faßhauer T, Bartels C, Ehrenreich H. Therapeutic potential of erythropoietin and its structural or functional variants in the nervous system. Neurotherapeutics 2009; 6:108-27. [PMID: 19110203 PMCID: PMC5084260 DOI: 10.1016/j.nurt.2008.10.041] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The growth factor erythropoietin (EPO) and erythropoietin receptors (EPOR) are expressed in the nervous system. Neuronal expression of EPO and EPOR peaks during brain development and is upregulated in the adult brain after injury. Peripherally administered EPO, and at least some of its variants, cross the blood-brain barrier, stimulate neurogenesis, neuronal differentiation, and activate brain neurotrophic, anti-apoptotic, anti-oxidant and anti-inflammatory signaling. These mechanisms underlie their tissue protective effects in nervous system disorders. As the tissue protective functions of EPO can be separated from its stimulatory action on hematopoiesis, novel EPO derivatives and mimetics, such as asialo-EPO and carbamoylated EPO have been developed. While the therapeutic potential of the novel EPO derivatives continues to be characterized in preclinical studies, the experimental findings in support for the use of recombinant human (rh)EPO in human brain disease have already been translated to clinical studies in acute ischemic stroke, chronic schizophrenia, and chronic progressive multiple sclerosis. In this review article, we assess the studies on EPO and, in particular, on its structural or functional variants in experimental models of nervous system disorders, and we provide a short overview of the completed and ongoing clinical studies testing EPO as neuroprotective/neuroregenerative treatment option in neuropsychiatric disease.
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Affiliation(s)
- Anna-Leena Sirén
- grid.8379.50000000119588658Department of Neurosurgery, University of Würzburg, Josef-Schneider Str. 11, 97080 Würzburg, Germany
| | - Theresa Faßhauer
- grid.8379.50000000119588658Department of Neurosurgery, University of Würzburg, Josef-Schneider Str. 11, 97080 Würzburg, Germany
| | - Claudia Bartels
- grid.419522.90000000106686902Division of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Hermann-Rein Str. 3, 37075 Göttingen, Germany
| | - Hannelore Ehrenreich
- grid.419522.90000000106686902Division of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Hermann-Rein Str. 3, 37075 Göttingen, Germany
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90
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Shi H. Hypoxia inducible factor 1 as a therapeutic target in ischemic stroke. Curr Med Chem 2009; 16:4593-600. [PMID: 19903149 PMCID: PMC2819104 DOI: 10.2174/092986709789760779] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2009] [Accepted: 11/13/2009] [Indexed: 11/22/2022]
Abstract
In stroke research, a significant focus is to develop therapeutic strategies that prevent neuronal death and improve recovery. Yet, few successful therapeutic strategies have emerged. Hypoxia-inducible factor 1 (HIF-1) is a key regulator in hypoxia. It has been suggested to be an important player in neurological outcomes following ischemic stroke due to the functions of its downstream genes. These include genes that promote glucose metabolism, angiogenesis, erythropoiesis, and cell survival. Many lines of evidence have shown that HIF-1 is induced in ischemic brains. Importantly, it seems that HIF-1 is primarily induced in the salvageable tissue of an ischemic brain, penumbra. However, the effect of HIF-1 on neuronal tissue injuries is still debatable based on evidence from in vitro and preclinical studies. Furthermore, it is of importance to understand the mechanism of HIF-1 degradation after its induction in ischemic brain. This review provides a present understanding of the mechanism of HIF-1 induction in ischemic neurons and the potential effect of HIF-1 on ischemic brain tissue. The author also elaborates on potential therapeutic approaches through understanding of the induction mechanism and of the potential role of HIF-1 in ischemic stroke.
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Affiliation(s)
- Honglian Shi
- Department of Pharmacology and Toxicology, University of Kansas, School of Pharmacy, 1251 Wescoe Hall Drive, Malott Hall 5044, Lawrence, KS 66045, USA.
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91
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Dudas M, Wysocki A, Gelpi B, Tuan TL. Memory encoded throughout our bodies: molecular and cellular basis of tissue regeneration. Pediatr Res 2008; 63:502-12. [PMID: 18427295 DOI: 10.1203/pdr.0b013e31816a7453] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
When a sheep loses its tail, it cannot regenerate it in the manner of lizards. On the other hand, it is possible to clone mammals from somatic cells, showing that a complete developmental program is intact in a wounded sheep's tail the same way it is in a lizard. Thus, there is a requirement for more than only the presence of the entire genetic code in somatic cells for regenerative abilities. Thoughts like this have motivated us to assemble more than just a factographic synopsis on tissue regeneration. As a model, we review skin wound healing in chronological order, and when possible, we use that overview as a framework to point out possible mechanisms of how damaged tissues can restore their original structure. This article postulates the existence of tissue structural memory as a complex distributed homeostatic mechanism. We support such an idea by referring to an extremely fragmented literature base, trying to synthesize a broad picture of important principles of how tissues and organs may store information about their own structure for the purposes of regeneration. Selected developmental, surgical, and tissue engineering aspects are presented and discussed in the light of recent findings in the field. When a sheep loses its tail, it cannot regenerate it in the manner of lizards. On the other hand, it is possible to clone mammals from somatic cells, showing that a complete developmental program is intact in a wounded sheep's tail the same way it is in a lizard. Thus, there is a requirement for more than only the presence of the entire genetic code in somatic cells for regenerative abilities. Thoughts like this have motivated us to assemble more than just a factographic synopsis on tissue regeneration. As a model, we review skin wound healing in chronological order, and when possible, we use that overview as a framework to point out possible mechanisms of how damaged tissues can restore their original structure. This article postulates the existence of tissue structural memory as a complex distributed homeostatic mechanism. We support such an idea by referring to an extremely fragmented literature base, trying to synthesize a broad picture of important principles of how tissues and organs may store information about their own structure for the purposes of regeneration. Selected developmental, surgical, and tissue engineering aspects are presented and discussed in the light of recent findings in the field.
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Affiliation(s)
- Marek Dudas
- Developmental Biology Program, The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA
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92
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Fong GH, Takeda K. Role and regulation of prolyl hydroxylase domain proteins. Cell Death Differ 2008; 15:635-41. [PMID: 18259202 DOI: 10.1038/cdd.2008.10] [Citation(s) in RCA: 274] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Oxygen-dependent hydroxylation of hypoxia-inducible factor (HIF)-alpha subunits by prolyl hydroxylase domain (PHD) proteins signals their polyubiquitination and proteasomal degradation, and plays a critical role in regulating HIF abundance and oxygen homeostasis. While oxygen concentration plays a major role in determining the efficiency of PHD-catalyzed hydroxylation reactions, many other environmental and intracellular factors also significantly modulate PHD activities. In addition, PHDs may also employ hydroxylase-independent mechanisms to modify HIF activity. Interestingly, while PHDs regulate HIF-alpha protein stability, PHD2 and PHD3 themselves are subject to feedback upregulation by HIFs. Functionally, different PHD isoforms may differentially contribute to specific pathophysiological processes, including angiogenesis, erythropoiesis, tumorigenesis, and cell growth, differentiation and survival. Because of diverse roles of PHDs in many different processes, loss of PHD expression or function triggers multi-faceted pathophysiological changes as has been shown in mice lacking different PHD isoforms. Future investigations are needed to explore in vivo specificity of PHDs over different HIF-alpha subunits and differential roles of PHD isoforms in different biological processes.
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Affiliation(s)
- G-H Fong
- Center for Vascular Biology, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030-3501, USA.
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93
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94
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Myllyharju J. Prolyl 4-hydroxylases, key enzymes in the synthesis of collagens and regulation of the response to hypoxia, and their roles as treatment targets. Ann Med 2008; 40:402-17. [PMID: 19160570 DOI: 10.1080/07853890801986594] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Prolyl 4-hydroxylases (P4Hs) have central roles in the synthesis of collagens and the regulation of oxygen homeostasis. The 4-hydroxyproline residues generated by the endoplasmic reticulum (ER) luminal collagen P4Hs (C-P4Hs) are essential for the stability of the collagen triple helix. Vertebrate C-P4Hs are alpha2beta2 tetramers with three isoenzymes differing in their catalytic alpha subunits. Another P4H family, the HIF-P4Hs, hydroxylates specific prolines in the alpha subunit of the hypoxia-inducible transcription factor (HIF), a master regulator of hypoxia-inducible genes, and controls its stability in an oxygen-dependent manner. The HIF-P4Hs are cytoplasmic and nuclear enzymes, likewise with three isoenzymes in vertebrates. A third vertebrate P4H type is an ER transmembrane protein that can act on HIF-alpha but not on collagens. All P4Hs require Fe2+, 2-oxoglutarate, O2, and ascorbate. C-P4Hs are regarded as attractive targets for pharmacological inhibition to control excessive collagen accumulation in fibrotic diseases and severe scarring, while HIF-P4H inhibitors are believed to have beneficial effects in the treatment of diseases such as myocardial infarction, stroke, peripheral vascular disease, diabetes, and severe anemias. Studies with P4H inhibitors in various animal models of fibrosis, anemia, and ischemia and ongoing clinical trials with HIF-P4H inhibitors support this hypothesis by demonstrating efficacy in many applications.
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