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| 2. |
- Bourghardt Peebo, Beatrice, et al.
(författare)
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Cellular level characterization of capillary regression in inflammatory angiogenesis using an in vivo corneal model
- 2011
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Ingår i: Angiogenesis. - : Springer Verlag (Germany). - 0969-6970 .- 1573-7209. ; 14:3, s. 393-405
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we introduce a technique for repeated, microscopic observation of single regressing capillaries in vivo in inflamed murine corneas. Natural capillary regression was initiated by removal of inflammatory stimulus during an active pro-angiogenic phase, while the additional impact of anti-angiogenic treatment with triamcinolone or bevazicumab was investigated. Capillaries regressed naturally within 1 week and treatments did not further enhance the natural regression. Morphologically, early-phase regression was characterized by significant lumen narrowing and a significant reduction in CD11b+ myeloid cell infiltration of the extracellular matrix. By 1 week, vascular remodeling occurred concomitant with CD11b+CD68+KiM2R+ mature macrophage localization on capillary walls. Empty conduits without blood flow, positive for collagen IV and devoid of vascular endothelium and pericytes, were apparent in vivo and by 3 weeks were more numerous than perfused capillaries. By 3 weeks, macrophages aggregated around remaining perfused capillaries and were observed in apposition with degrading capillary segments. Abrupt termination of capillary sprouting in our regression model further revealed vascular endothelial abandonment of sprout tips and perfused capillary loop formation within a single angiogenic sprout, possibly as an intussusceptive response to cessation of the stimulus. Finally, we observed lumen constriction and macrophage localization on capillary walls in vivo in a clinical case of corneal capillary regression that paralleled findings in our murine model.
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| 3. |
- Cedervall, Jessica, et al.
(författare)
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HRG regulates tumor progression, epithelial to mesenchymal transition and metastasis via platelet-induced signaling in the pre-tumorigenic microenvironment
- 2013
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Ingår i: Angiogenesis. - : Springer Science and Business Media LLC. - 0969-6970 .- 1573-7209. ; 16:4, s. 889-902
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Tidskriftsartikel (refereegranskat)abstract
- Mice lacking histidine-rich glycoprotein (HRG) display an accelerated angiogenic switch and larger tumors-a phenotype caused by enhanced platelet activation in the HRG-deficient mice. Here we show that platelets induce molecular changes in the pre-tumorigenic environment in HRG-deficient mice, promoting cell survival, angiogenesis and epithelial-to-mesenchymal transition (EMT) and that these effects involved signaling via TBK1, Akt2 and PDGFR beta. These early events subsequently translate into an enhanced rate of spontaneous metastasis to distant organs in mice lacking HRG. Later in tumor development characteristic features of pathological angiogenesis, such as decreased perfusion and pericyte coverage, are more pronounced in HRG-deficient mice. At this stage, platelets are essential to support the larger tumor volumes formed in mice lacking HRG by keeping their tumor vasculature sufficiently functional. We conclude that HRG-deficiency promotes tumor progression via enhanced platelet activity and that platelets play a dual role in this process. During early stages of transformation, activated platelets promote tumor cell survival, the angiogenic switch and invasiveness. In the more progressed tumor, platelets support the enhanced pathological angiogenesis and hence increased tumor growth seen in the absence of HRG. Altogether, our findings strengthen the notion of HRG as a potent tumor suppressor, with capacity to attenuate the angiogenic switch, tumor growth, EMT and subsequent metastatic spread, by regulating platelet activity.
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| 4. |
- Christoffersson, Gustav, et al.
(författare)
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Vascular adaptation to a dysfunctional endothelium as a consequence of Shb deficiency
- 2012
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Ingår i: Angiogenesis. - : Springer Science and Business Media LLC. - 0969-6970 .- 1573-7209. ; 15:3, s. 469-480
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factor (VEGF)-A regulates angiogenesis, vascular morphology and permeability by signaling through its receptor VEGFR-2. The Shb adapter protein has previously been found to relay certain VEGFR-2 dependent signals and consequently vascular physiology and structure was assessed in Shb knockout mice. X-ray computed tomography of vessels larger than 24 mm diameter (micro-CT) after contrast injection revealed an increased frequency of 48-96 µm arterioles in the hindlimb calf muscle in Shb knockout mice. Intravital microscopy of the cremaster muscle demonstrated a less regular vasculature with fewer branch points and increased vessel tortuosity, changes that led to an increased blood flow velocity. Reduced in vivo angiogenesis was observed in Shb knockout MatrigelTM plugs. Unlike the wild-type situation, VEGF-A did not provoke a dissociation of VE-cadherin from adherens junctions in Shb knockout venules. The reduced angiogenesis and altered properties of junctions had consequences for two patho-physiological responses to arterial occlusion: vascular permeability was reduced in the Shb knockout cremaster muscle after ligation of one supplying artery and heat-induced blood flow determined by Laser-Doppler measurements was decreased in the hindlimb after ligation of the femoral artery. Consequently, the Shb knockout mouse exhibited structural and functional (angiogenesis and vascular permeability) vascular abnormalities that have implications for understanding the function of VEGF-A under physiological conditions.
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| 6. |
- Coma, Silvia, et al.
(författare)
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GATA2 and Lmo2 control angiogenesis and lymphangiogenesis via direct transcriptional regulation of neuropilin-2
- 2013
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Ingår i: Angiogenesis. - : Springer Science and Business Media LLC. - 0969-6970 .- 1573-7209. ; 16:4, s. 939-952
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Tidskriftsartikel (refereegranskat)abstract
- GATA-binding protein 2 (GATA2) and LIM domain only 2 (Lmo2) form common transcription complexes during hematopoietic differentiation. Here we show that these two transcription factors also play a key role in endothelial cells (EC) and lymphatic EC (LEC) function. Primary EC and tumor-associated blood vessels expressed GATA2 and Lmo2. VEGF-induced sprouting angiogenesis in both differentiating embryonic stem cells (embryoid bodies) and primary EC increased GATA2 and Lmo2 levels. Conversely, silencing of GATA2 and Lmo2 expression in primary EC inhibited VEGF-induced angiogenic activity, including EC migration and sprouting in vitro, two key steps of angiogenesis in vivo. This inhibition of EC function was associated with downregulated expression of neuropilin-2 (NRP2), a co-receptor of VEGFRs for VEGF, at the protein, mRNA and promoter levels. NRP2 overexpression partially rescued the impaired angiogenic sprouting in the GATA2/Lmo2 knockdown EC, confirming that GATA2 and Lmo2 mediated EC function, at least in part, by directly regulating NRP2 gene expression. Furthermore, it was found that primary LEC expressed GATA2 and Lmo2 as well. Silencing of GATA2 and Lmo2 expression in LEC inhibited VEGF-induced LEC sprouting, also in a NRP2-dependent manner. In conclusion, our results demonstrate that GATA2 and Lmo2 cooperatively regulate VEGF-induced angiogenesis and lymphangiogenesis via NRP2.
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| 7. |
- Dieterich, Lothar C., et al.
(författare)
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alpha B-crystallin/HspB5 regulates endothelial-leukocyte interactions by enhancing NF-kappa B-induced up-regulation of adhesion molecules ICAM-1, VCAM-1 and E-selectin
- 2013
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Ingår i: Angiogenesis. - : Springer Science and Business Media LLC. - 0969-6970 .- 1573-7209. ; 16:4, s. 975-983
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Tidskriftsartikel (refereegranskat)abstract
- alpha B-crystallin is a small heat shock protein, which has pro-angiogenic properties by increasing survival of endothelial cells and secretion of vascular endothelial growth factor A. Here we demonstrate an additional role of alpha B-crystallin in regulating vascular function, through enhancing tumor necrosis factor alpha (TNF-alpha) induced expression of endothelial adhesion molecules involved in leukocyte recruitment. Ectopic expression of alpha B-crystallin in endothelial cells increases the level of E-selectin expression in response to TNF-alpha, and enhances leukocyte-endothelial interaction in vitro. Conversely, TNF-alpha-induced expression of intercellular adhesion molecule 1, vascular cell adhesion molecule 1 and E-selectin is markedly inhibited in endothelial cells isolated from alpha B-crystallin-deficient mice. This is associated with elevated levels of I kappa B in alpha B-crystallin deficient cells and incomplete degradation upon TNF-alpha stimulation. Consistent with this, endothelial adhesion molecule expression is reduced in inflamed vessels of alpha B-crystallin deficient mice, and leukocyte rolling velocity is increased. Our data identify alpha B-crystallin as a new regulator of leukocyte recruitment, by enhancing pro-inflammatory nuclear factor kappa B-signaling and endothelial adhesion molecule expression during endothelial activation.
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| 11. |
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| 12. |
- Kilarski, Witold W, et al.
(författare)
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An in vivo neovascularization assay for screening regulators of angiogenesis and assessing their effects on pre-existing vessels
- 2012
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Ingår i: Angiogenesis. - : Springer Science and Business Media LLC. - 0969-6970 .- 1573-7209. ; 15:4, s. 643-655
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Tidskriftsartikel (refereegranskat)abstract
- Therapeutic regulation of tissue vascularization has appeared as an attractive approach to treat a number of human diseases. In vivo neovascularization assays that reflect physiological and pathological formation of neovessels are important in this effort. In this report we present an assay where the effects of activators and inhibitors of angiogenesis can be quantitatively and qualitatively measured. A provisional matrix composed of collagen I and fibrin was formed in a plastic cylinder and implanted onto the chick chorioallantoic membrane. A nylon mesh separated the implanted matrix from the underlying tissue to distinguish new from pre-existing vessels. Vascularization of the matrix in response to fibroblast growth factor-2 or platelet-derived growth factor-BB was scored in a double-blinded manner, or vessel density was measured using a semi-automated image analysis procedure. Thalidomide, fumagillin, U0126 and TGFβ inhibited neovessel growth while hydrocortisone exerted a negative and wortmannin a toxic effect on the pre-existing vasculature. This quantitative, inexpensive and rapid in vivo angiogenesis assay might be a valuable tool in screening and characterizing factors that influence wound or tumor induced vascularization and in assessing their effects on the normal vasculature.
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| 15. |
- Siemsen, BL, et al.
(författare)
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Role of ramp2 in angiogenesis
- 2013
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Ingår i: ANGIOGENESIS. - 0969-6970. ; 16:1, s. 261-262
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 16. |
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