| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
- Xue, Yuan, et al.
(författare)
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PDGF-BB modulates hematopoiesis and tumor angiogenesis by inducing erythropoietin production in stromal cells
- 2012
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Ingår i: Nature Medicine. - : Nature Publishing Group. - 1078-8956 .- 1546-170X. ; 18:1, s. 100-110
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Tidskriftsartikel (refereegranskat)abstract
- The platelet-derived growth factor (PDGF) signaling system contributes to tumor angiogenesis and vascular remodeling. Here we show in mouse tumor models that PDGF-BB induces erythropoietin (EPO) mRNA and protein expression by targeting stromal and perivascular cells that express PDGF receptor-beta (PDGFR-beta). Tumor-derived PDGF-BB promoted tumor growth, angiogenesis and extramedullary hematopoiesis at least in part through modulation of EPO expression. Moreover, adenoviral delivery of PDGF-BB to tumor-free mice increased both EPO production and erythropoiesis, as well as protecting from irradiation-induced anemia. At the molecular level, we show that the PDGF-BB PDGFR-beta signaling system activates the EPO promoter, acting in part through transcriptional regulation by the transcription factor Atf3, possibly through its association with two additional transcription factors, c-Jun and Sp1. Our findings suggest that PDGF-BB-induced EPO promotes tumor growth through two mechanisms: first, paracrine stimulation of tumor angiogenesis by direct induction of endothelial cell proliferation, migration, sprouting and tube formation, and second, endocrine stimulation of extramedullary hematopoiesis leading to increased oxygen perfusion and protection against tumor-associated anemia.
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