| 1. |
- Corada, Monica, et al.
(författare)
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Fine-Tuning of Sox17 and Canonical Wnt Coordinates the Permeability Properties of the Blood-Brain Barrier
- 2019
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Ingår i: Circulation Research. - 0009-7330 .- 1524-4571. ; 124:4, s. 511-525
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: The microvasculature of the central nervous system includes the blood-brain barrier (BBB), which regulates the permeability to nutrients and restricts the passage of toxic agents and inflammatory cells. Canonical Wnt/β-catenin signaling is responsible for the early phases of brain vascularization and BBB differentiation. However, this signal declines after birth, and other signaling pathways able to maintain barrier integrity at postnatal stage are still unknown.Objective: Sox17 (SRY [sex-determining region Y]-box 17) constitutes a major downstream target of Wnt/β-catenin in endothelial cells and regulates arterial differentiation. In the present article, we asked whether Sox17 may act downstream of Wnt/β-catenin in inducing BBB differentiation and maintenance.Methods and Results: Using reporter mice and nuclear staining of Sox17 and β-catenin, we report that although β-catenin signaling declines after birth, Sox17 activation increases and remains high in the adult. Endothelial-specific inactivation of Sox17 leads to increase of permeability of the brain microcirculation. The severity of this effect depends on the degree of BBB maturation: it is strong in the embryo and progressively declines after birth. In search of Sox17 mechanism of action, RNA sequencing analysis of gene expression of brain endothelial cells has identified members of the Wnt/β-catenin signaling pathway as downstream targets of Sox17. Consistently, we found that Sox17 is a positive inducer of Wnt/β-catenin signaling, and it acts in concert with this pathway to induce and maintain BBB properties. In vivo, inhibition of the β-catenin destruction complex or expression of a degradation-resistant β-catenin mutant, prevent the increase in permeability and retina vascular malformations observed in the absence of Sox17.Conclusions: Our data highlight a novel role for Sox17 in the induction and maintenance of the BBB, and they underline the strict reciprocal tuning of this transcription factor and Wnt/β-catenin pathway. Modulation of Sox17 activity may be relevant to control BBB permeability in pathological conditions.
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| 2. |
- Globisch, Maria A., et al.
(författare)
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Immunothrombosis and vascular heterogeneity in cerebral cavernous malformation
- 2022
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 140:20, s. 2154-2169
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral cavernous malformation (CCM) is a neurovascular disease that results in various neurological symptoms. Thrombi have been reported in surgically resected CCM patient biopsies, but the molecular signatures of these thrombi remain elusive. Here, we investigated the kinetics of thrombi formation in CCM and how thrombi affect the vasculature and contribute to cerebral hypoxia. We used RNA sequencing to investigate the transcriptome of mouse brain endothelial cells with an inducible endothelial-specific Ccm3 knock-out (Ccm3-iECKO). We found that Ccm3-deficient brain endothelial cells had a higher expression of genes related to the coagulation cascade and hypoxia when compared with wild-type brain endothelial cells. Immunofluorescent assays identified key molecular signatures of thrombi such as fibrin, von Willebrand factor, and activated platelets in Ccm3-iECKO mice and human CCM biopsies. Notably, we identified polyhedrocytes in Ccm3-iECKO mice and human CCM biopsies and report it for the first time. We also found that the parenchyma surrounding CCM lesions is hypoxic and that more thrombi correlate with higher levels of hypoxia. We created an in vitro model to study CCM pathology and found that human brain endothelial cells deficient for CCM3 expressed elevated levels of plasminogen activator inhibitor-1 and had a redistribution of von Willebrand factor. With transcriptomics, comprehensive imaging, and an in vitro CCM preclinical model, this study provides experimental evidence that genes and proteins related to the coagulation cascade affect the brain vasculature and promote neurological side effects such as hypoxia in CCMs. This study supports the concept that antithrombotic therapy may be beneficial for patients with CCM.
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| 3. |
- Gordon, Emma J., et al.
(författare)
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The endothelial adaptor molecule TSAd is required for VEGF-induced angiogenic sprouting through junctional c-Src activation
- 2016
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Ingår i: Science Signaling. - : American Association for the Advancement of Science (AAAS). - 1945-0877 .- 1937-9145. ; 9:437
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Tidskriftsartikel (refereegranskat)abstract
- Activation of vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) by VEGF binding is critical for vascular morphogenesis. In addition, VEGF disrupts the endothelial barrier by triggering the phosphorylation and turnover of the junctional molecule VE-cadherin, a process mediated by the VEGFR2 downstream effectors T cell-specific adaptor (TSAd) and the tyrosine kinase c-Src. We investigated whether the VEGFR2-TSAd-c-Src pathway was required for angiogenic sprouting. Indeed, Tsad-deficient embryoid bodies failed to sprout in response to VEGF. Tsad-deficient mice displayed impaired angiogenesis specifically during tracheal vessel development, but not during retinal vasculogenesis, and in VEGF-loaded Matrigel plugs, but not in those loaded with FGF. The SH2 and proline-rich domains of TSAd bridged VEGFR2 and c-Src, and this bridging was critical for the localization of activated c-Src to endothelial junctions and elongation of the growing sprout, but not for selection of the tip cell. These results revealed that vascular sprouting and permeability are both controlled through the VEGFR2-TSAd-c-Src signaling pathway in a subset of tissues, which may be useful in developing strategies to control tissue-specific pathological angiogenesis.
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| 4. |
- Malinverno, Matteo, et al.
(författare)
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Endothelial cell clonal expansion in the development of cerebral cavernous malformations
- 2019
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral cavernous malformation (CCM) is a neurovascular familial or sporadic disease that is characterised by capillary-venous cavernomas, and is due to loss-of-function mutations to any one of three CCM genes. Familial CCM follows a two-hit mechanism similar to that of tumour suppressor genes, while in sporadic cavernomas only a small fraction of endothelial cells shows mutated CCM genes. We reported that in mouse models and in human patients, endothelial cells lining the lesions have different features from the surrounding endothelium, as they express mesenchymal/stem-cell markers. Here we show that cavernomas originate from clonal expansion of few Ccm3-null endothelial cells that express mesenchymal/stem-cell markers. These cells then attract surrounding wild-type endothelial cells, inducing them to express mesenchymal/stem-cell markers and to contribute to cavernoma growth. These characteristics of Ccm3-null cells are reminiscent of the tumour-initiating cells that are responsible for tumour growth. Our data support the concept that CCM has benign tumour characteristics.
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| 5. |
- Oldenburg, Joppe, et al.
(författare)
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Propranolol Reduces the Development of Lesions and Rescues Barrier Function in Cerebral Cavernous Malformations : A Preclinical Study
- 2021
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Ingår i: Stroke. - : Lippincott Williams & Wilkins. - 0039-2499 .- 1524-4628. ; 52:4, s. 1418-1427
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose: Cerebral cavernous malformations (CCM) present as mulberry-like malformations of the microvasculature of the central nervous system. Current medical treatment of CCM lesions is limited to surgical removal of the vascular malformations. It is, therefore, important to identify therapeutic drug treatments for patients with CCM. Propranolol has shown great benefit in the treatment of infantile hemangioma. In addition, patients with CCM who receive propranolol have demonstrated a reduction of their lesions. Our investigation set out to provide preclinical data to support propranolol as a therapeutic treatment.Methods: An inducible endothelial-specific Ccm3 knockout murine model (CCM3(iECKO)) was used, with assessment of lesion quantity and size following oral treatment with propranolol. Scanning and transmission electron microscopy were used to characterize the CCM3(iECKO) lesions and the effects of propranolol on the disease. Immunofluorescent imaging was used to investigate pericyte coverage in the propranolol-treated CCM3(iECKO) mice.Results: With propranolol treatment, the lesion quantity, size, and volume decreased in both the brain and retina in the CCM3(iECKO) model. Novel characteristics of the CCM3(iECKO) lesions were discovered using electron microscopy, including plasmalemmal pits and thickening of the endothelial-pericyte basal membrane. These characteristics were absent with propranolol treatment. Pericyte coverage of the CCM3(iECKO) lesions increased after propranolol treatment, and vascular leakage was reduced.Conclusions: This study supports the concept that propranolol can be used to reduce and stabilize vascular lesions and can, therefore, be suggested as a pharmaceutical treatment for CCM.
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| 6. |
- Orsenigo, Fabrizio, et al.
(författare)
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Mapping endothelial-cell diversity in cerebral cavernous malformations at single-cell resolution
- 2020
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Ingår i: eLIFE. - : eLife Sciences Publications, Ltd. - 2050-084X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral cavernous malformation (CCM) is a rare neurovascular disease that is characterized by enlarged and irregular blood vessels that often lead to cerebral hemorrhage. Loss-of-function mutations to any of three genes results in CCM lesion formation; namely, KRIT1, CCM2, and PDCD10 (CCM3). Here, we report for the first time in-depth single-cell RNA sequencing, combined with spatial transcriptomics and immunohistochemistry, to comprehensively characterize subclasses of brain endothelial cells (ECs) under both normal conditions and after deletion of Pdcd10 (Ccm3) in a mouse model of CCM. Integrated single-cell analysis identifies arterial ECs as refractory to CCM transformation. Conversely, a subset of angiogenic venous capillary ECs and respective resident endothelial progenitors appear to be at the origin of CCM lesions. These data are relevant for the understanding of the plasticity of the brain vascular system and provide novel insights into the molecular basis of CCM disease at the single cell level.
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| 7. |
- Yau, Anthony C. Y., et al.
(författare)
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Inflammation and neutrophil extracellular traps in cerebral cavernous malformation
- 2022
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Ingår i: Cellular and Molecular Life Sciences (CMLS). - : Springer Nature. - 1420-682X .- 1420-9071. ; 79:4
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral Cavernous Malformation (CCM) is a brain vascular disease with various neurological symptoms. In this study, we describe the inflammatory profile in CCM and show for the first time the formation of neutrophil extracellular traps (NETs) in rodents and humans with CCM. Through RNA-seq analysis of cerebellum endothelial cells from wild-type mice and mice with an endothelial cell-specific ablation of the Ccm3 gene (Ccm3(iECKO)), we show that endothelial cells from Ccm3(iECKO) mice have an increased expression of inflammation-related genes. These genes encode proinflammatory cytokines and chemokines, as well as adhesion molecules, which promote recruitment of inflammatory and immune cells. Similarly, immunoassays showed elevated levels of these cytokines and chemokines in the cerebellum of the Ccm3(iECKO) mice. Consistently, both flow cytometry and immunofluorescence analysis showed infiltration of different subsets of leukocytes into the CCM lesions. Neutrophils, which are known to fight against infection through different strategies, including the formation of NETs, represented the leukocyte subset within the most pronounced increase in CCM. Here, we detected elevated levels of NETs in the blood and the deposition of NETs in the cerebral cavernomas of Ccm3(iECKO) mice. Degradation of NETs by DNase I treatment improved the vascular barrier. The deposition of NETs in the cavernomas of patients with CCM confirms the clinical relevance of NETs in CCM.
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| 8. |
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