| 1. |
- Alvarez, Yolanda, et al.
(författare)
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Selective inhibition of retinal angiogenesis by targeting PI3 kinase
- 2009
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 4:11, s. e7867-
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Tidskriftsartikel (refereegranskat)abstract
- Ocular neovascularisation is a pathological hallmark of some forms of debilitating blindness including diabetic retinopathy, age related macular degeneration and retinopathy of prematurity. Current therapies for delaying unwanted ocular angiogenesis include laser surgery or molecular inhibition of the pro-angiogenic factor VEGF. However, targeting of angiogenic pathways other than, or in combination to VEGF, may lead to more effective and safer inhibitors of intraocular angiogenesis. In a small chemical screen using zebrafish, we identify LY294002 as an effective and selective inhibitor of both developmental and ectopic hyaloid angiogenesis in the eye. LY294002, a PI3 kinase inhibitor, exerts its anti-angiogenic effect in a dose-dependent manner, without perturbing existing vessels. Significantly, LY294002 delivered by intraocular injection, significantly inhibits ocular angiogenesis without systemic side-effects and without diminishing visual function. Thus, targeting of PI3 kinase pathways has the potential to effectively and safely treat neovascularisation in eye disease.
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| 2. |
- Brautigam, Lars, et al.
(författare)
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Glutaredoxin regulates vascular development by reversible glutathionylation of sirtuin 1
- 2013
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 110:50, s. 20057-20062
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Tidskriftsartikel (refereegranskat)abstract
- Embryonic development depends on complex and precisely orchestrated signaling pathways including specific reduction/oxidation cascades. Oxidoreductases of the thioredoxin family are key players conveying redox signals through reversible posttranslational modifications of protein thiols. The importance of this protein family during embryogenesis has recently been exemplified for glutaredoxin 2, a vertebrate-specific glutathione-disulfide oxidoreductase with a critical role for embryonic brain development. Here, we discovered an essential function of glutaredoxin 2 during vascular development. Confocal microscopy and time-lapse studies based on two-photon microscopy revealed that morpholino-based knockdown of glutaredoxin 2 in zebrafish, a model organism to study vertebrate embryogenesis, resulted in a delayed and disordered blood vessel network. We were able to show that formation of a functional vascular system requires glutaredoxin 2-dependent reversible S-glutathionylation of the NAD(+)-dependent protein deacetylase sirtuin 1. Using mass spectrometry, we identified a cysteine residue in the conserved catalytic region of sirtuin 1 as target for glutaredoxin 2-specific deglutathionylation. Thereby, glutaredoxin 2-mediated redox regulation controls enzymatic activity of sirtuin 1, a mechanism we found to be conserved between zebrafish and humans. These results link S-glutathionylation to vertebrate development and successful embryonic angiogenesis.
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| 3. |
- Cao, Renhai, et al.
(författare)
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Hypoxia-induced retinal angiogenesis in zebrafish as a model to study retinopathy
- 2008
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 3:7, s. e2748-
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Tidskriftsartikel (refereegranskat)abstract
- Mechanistic understanding and defining novel therapeutic targets of diabetic retinopathy and age-related macular degeneration (AMD) have been hampered by a lack of appropriate adult animal models. Here we describe a simple and highly reproducible adult fli-EGFP transgenic zebrafish model to study retinal angiogenesis. The retinal vasculature in the adult zebrafish is highly organized and hypoxia-induced neovascularization occurs in a predictable area of capillary plexuses. New retinal vessels and vascular sprouts can be accurately measured and quantified. Orally active anti-VEGF agents including sunitinib and ZM323881 effectively block hypoxia-induced retinal neovascularization. Intriguingly, blockage of the Notch signaling pathway by the inhibitor DAPT under hypoxia, results in a high density of arterial sprouting in all optical arteries. The Notch suppression-induced arterial sprouting is dependent on tissue hypoxia. However, in the presence of DAPT substantial endothelial tip cell formation was detected only in optic capillary plexuses under normoxia. These findings suggest that hypoxia shifts the vascular targets of Notch inhibitors. Our findings for the first time show a clinically relevant retinal angiogenesis model in adult zebrafish, which might serve as a platform for studying mechanisms of retinal angiogenesis, for defining novel therapeutic targets, and for screening of novel antiangiogenic drugs.
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| 4. |
- Dahl Jensen, Lasse, et al.
(författare)
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Opposing Effects of Circadian Clock Genes Bmal1 and Period2 in Regulation of VEGF-Dependent Angiogenesis in Developing Zebrafish
- 2012
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Ingår i: Cell Reports. - : Elsevier (Cell Press). - 2211-1247. ; 2:2, s. 231-241
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Tidskriftsartikel (refereegranskat)abstract
- Molecular mechanisms underlying circadian-regulated physiological processes remain largely unknown. Here, we show that disruption of the circadian clock by both constant exposure to light and genetic manipulation of key genes in zebrafish led to impaired developmental angiogenesis. A bmal1-specific morpholino inhibited developmental angiogenesis in zebrafish embryos without causing obvious nonvascular phenotypes. Conversely, a period2 morpholino accelerated angiogenic vessel growth, suggesting that Bmal1 and Period2 display opposing angiogenic effects. Using a promoter-reporter system consisting of various deleted vegf-promoter mutants, we show that Bmal1 directly binds to and activates the vegf promoter via E-boxes. Additionally, we provide evidence that knockdown of Bmal1 leads to impaired Notch-inhibition-induced vascular sprouting. These results shed mechanistic insight on the role of the circadian clock in regulation of developmental angiogenesis, and our findings may be reasonably extended to other types of physiological or pathological angiogenesis.
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| 5. |
- Dahl Jensen, Lasse, et al.
(författare)
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Zebrafish Models to Study Hypoxia-Induced Pathological Angiogenesis in Malignant and Nonmalignant Diseases
- 2011
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Ingår i: Birth Defects Research. Part C: Embryo Today Reviews. - : John Wiley and Sons.Ltd. - 1542-975X .- 1542-9768. ; 93:2, s. 182-193
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Forskningsöversikt (refereegranskat)abstract
- Most in vivo preclinical disease models are based on mouse and other mammalian systems. However, these rodent-based model systems have considerable limitations to recapitulate clinical situations in human patients. Zebrafish have been widely used to study embryonic development, behavior, tissue regeneration, and genetic defects. Additionally, zebrafish also provides an opportunity to screen chemical compounds that target a specific cell population for drug development. Owing to the availability of various genetically manipulated strains of zebrafish, immune privilege during early embryonic development, transparency of the embryos, and easy and precise setup of hypoxia equipment, we have developed several disease models in both embryonic and adult zebrafish, focusing on studying the role of angiogenesis in pathological settings. These zebrafish disease models are complementary to the existing mouse models, allowing us to study clinically relevant processes in cancer and nonmalignant diseases, which otherwise would be difficult to study in mice. For example, dissemination and invasion of single human or mouse tumor cells from the primary site in association with tumor angiogenesis can be studied under normoxia or hypoxia in zebrafish embryos. Hypoxia-induced retinopathy in the adult zebrafish recapitulates the clinical situation of retinopathy development in diabetic patients or age-related macular degeneration. These zebrafish disease models offer exciting opportunities to understand the mechanisms of disease development, progression, and development of more effective drugs for therapeutic intervention.
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| 6. |
- Gnosa, Sebastian, et al.
(författare)
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AEG-1 knockdown in colon cancer cell lines inhibits radiation-enhanced migration and invasion in vitro and in a novel in vivo zebrafish model
- 2016
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Ingår i: Oncotarget. - : Impact Journals. - 1949-2553. ; 7:49, s. 81634-81644
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Tidskriftsartikel (refereegranskat)abstract
- Background Radiotherapy is a well-established anti-cancer treatment. Although radiotherapy has been shown to significantly decrease the local relapse in rectal cancer patients, the rate of distant metastasis is still very high. Several studies have shown that radiation enhances migration and invasion both in vitro and in vivo. The aim of this study was to evaluate whether AEG-1 is involved in radiation-enhanced migration and invasion in vitro and in a novel in vivo zebrafish model.Materials and Methods We evaluated the involvement of AEG-1 in migration and invasion and radiation-enhanced migration and invasion by Boyden chamber assay in three colon cancer cell lines and respective AEG-1 knockdown cell lines. Furthermore, we injected the cells in zebrafish embryos and evaluated the amount of disseminated cells into the tail.Results Migration and invasion was decreased in all the AEG-1 knockdown cell lines. Furthermore, radiation enhanced migration and invasion, while AEG-1 knockdown could abolish this effect. The results from the zebrafish model confirmed the results obtained in vitro. MMP-9 secretion and expression were decreased in AEG-1 knockdown cells.Conclusion Our results demonstrate that AEG-1 knockdown inhibits migration and invasion, as well as radiation-enhanced migration and invasion. We speculate that this is done via the downregulation of the intrinsic or radiation-enhanced MMP-9 expression. The zebrafish model can be used to study early events in radiation-enhanced invasion.
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| 7. |
- Jensen, Lasse Dahl, et al.
(författare)
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Circadian angiogenesis
- 2014
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Ingår i: Biomolecular concepts. - : Walter de Gruyter GmbH. - 1868-503X .- 1868-5021. ; 5:3, s. 245-56
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Tidskriftsartikel (refereegranskat)abstract
- Daily rhythms of light/darkness, activity/rest and feeding/fasting are important in human physiology and their disruption (for example by frequent changes between day and night shifts) increases the risk of disease. Many of the diseases found to be associated with such disrupted circadian lifestyles, including cancer, cardiovascular diseases, metabolic disorders and neurological diseases, depend on pathological de-regulation of angiogenesis, suggesting that disrupting the circadian clock will impair the physiological regulation of angiogenesis leading to development and progression of these diseases. Today there is little known regarding circadian regulation of pathological angiogenesis but there is some evidence that supports both direct and indirect regulation of angiogenic factors by the cellular circadian clock machinery, as well as by circulating circadian factors, important for coordinating circadian rhythms in the organism. Through highlighting recent advances both in pre-clinical and clinical research on various diseases including cancer, cardiovascular disorders and obesity, we will here present an overview of the available knowledge on the importance of circadian regulation of angiogenesis and discuss how the circadian clock may provide alternative targets for pro- or anti-angiogenic therapy in the future.
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| 8. |
- Jensen, Lasse Dahl, et al.
(författare)
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Clock controls angiogenesis
- 2013
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Ingår i: Cell Cycle. - : Landes Bioscience. - 1538-4101 .- 1551-4005. ; 12:3, s. 405-408
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Tidskriftsartikel (refereegranskat)abstract
- Circadian rhythms control multiple physiological and pathological processes, including embryonic development in mammals and development of various human diseases. We have recently, in a developing zebrafish embryonic model, discovered that the circadian oscillation controls developmental angiogenesis. Disruption of crucial circadian regulatory genes, including Bmal1 and Period2, results in marked impairment or enhancement of vascular development in zebrafish. At the molecular level, we show that the circadian regulator Bmal1 directly targets the promoter region of the vegf gene in zebrafish, leading to an elevated expression of VEGF. These findings can reasonably be extended to developmental angiogenesis in mammals and even pathological angiogenesis in humans. Thus, our findings, for the first time, shed new light on mechanisms that underlie circadian clock-regulated angiogenesis.
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| 9. |
- Jensen, Lasse Dahl Ejby
(författare)
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Mechanisms of malignant and non-malignant angiogenesis using zebrafish models
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Pathological angiogenesis significantly contribute to the onset, development and progression of most common and severe human diseases including cancer, metastatic disease, cardiovascular disease, age-related macular degeneration, diabetic retinopathy and retinopathy of prematurity. Under these pathological conditions, tissue hypoxia often acts as a trigger to switch on angiogenesis. However, there has been lacking non-invasive and clinically relevant animal models that allow us to study mechanisms of human diseases. Zebrafish, as a complementary animal model to mice, is a highly genetically and pharmacologically tractable vertebrate which is easily visualized during development. Zebrafish offers a unique opportunity to study angiogenesis under hypoxia. This thesis describes development and characterization of four novel zebrafish models in relation to hypoxia-induced angiogenesis, vascular and tumor pathology. Using these models, we demonstrate that hypoxia plays a causal role in development of retinopathy and cancer cell metastasis and thus provide important insights needed for the development of therapeutic approaches aimed at interfering with these processes. In paper I, we showed that hypoxia could induce neovascular retinopathy in zebrafish and this model is highly relevant to clinical retinopathy caused by diabetes. This zebrafish retinopathy model also allows us study the therapeutic potential of various antiangiogenic agents. In paper II, we demonstrate a novel principle that regulates blood perfusion in lymphatics as an effective defense against tissue hypoxia in zebrafish and kryptopterus bicirrhis. The arterial-lymphatic shunt is controlled by nitric oxide and the implication of this work is that NO-induced lymphatic perfusion might facilitate tumor cell spread from the blood stream into the lymphatic system. In paper III, we take advantage of the transparent nature of zebrafish embryos and availability of the transgenic strain fli1:EGFP to develop a zebrafish metastasis model. Using this model, we are the first to study the role of hypoxia in relation to angiogenesis in facilitating tumor cell dissemination, invasion and metastasis. To the best of our knowledge, this is the first animal model that allows scientists to study the early events of metastasis at a single cell level. In paper IV, We show that PI3 kinase is a key signaling component that mediates angiogenesis in the developing embryonic retina and in the regenerating adult fins. In conclusion, development of these zebrafish disease models have paved new avenues for studying mechanisms of pathological angiogenesis in malignant and non malignant diseases and offers unique opportunities for assessment of therapeutic potentials of known and novel drugs against these most common and lethal diseases.
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| 10. |
- Jensen, Lasse Dahl, et al.
(författare)
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In vivo angiogenesis and lymphangiogenesis models
- 2009
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Ingår i: Current molecular medicine. - : Bentham Science Publishers. - 1566-5240 .- 1875-5666. ; 9:8, s. 982-991
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Tidskriftsartikel (refereegranskat)abstract
- Angiogenesis research has become one of the most important areas in biomedical research. At the time of writing this review, there were approximately 3536 articles published in the year of 2008 alone on the topic of angiogenesis. The fast expansion of this research field demands development of rigorous, reliable, stable, convenient, and clinically relevant assay systems for disease diagnosis, prognosis, therapeutic evaluation, drug discovery, and mechanistic studies at the molecular level. Here, we discuss several commonly used in vivo angiogenesis models by systematically analyzing and pointing out pitfalls of each assay. Owing to existence of numerous assays and the limitation of text, it is impossible to discuss all these assays in this article. Here we select several most commonly used angiogenesis assays performed in various species including mice, chicks and zebrafish for further in-depth discussion. We hope this information will be valuable for improving current angiogenesis research.
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