| 1. |
- Angiolini, Francesca, et al.
(författare)
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A novel L1CAM isoform with angiogenic activity generated by NOVA2-mediated alternative splicing
- 2019
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Ingår i: eLIFE. - 2050-084X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The biological players involved in angiogenesis are only partially defined. Here, we report that endothelial cells (ECs) express a novel isoform of the cell-surface adhesion molecule L1CAM, termed L1-ΔTM. The splicing factor NOVA2, which binds directly to L1CAM pre-mRNA, is necessary and sufficient for the skipping of L1CAM transmembrane domain in ECs, leading to the release of soluble L1-ΔTM. The latter exerts high angiogenic function through both autocrine and paracrine activities. Mechanistically, L1-ΔTM-induced angiogenesis requires fibroblast growth factor receptor-1 signaling, implying a crosstalk between the two molecules. NOVA2 and L1-ΔTM are overexpressed in the vasculature of ovarian cancer, where L1-ΔTM levels correlate with tumor vascularization, supporting the involvement of NOVA2-mediated L1-ΔTM production in tumor angiogenesis. Finally, high NOVA2 expression is associated with poor outcome in ovarian cancer patients. Our results point to L1-ΔTM as a novel, EC-derived angiogenic factor which may represent a target for innovative antiangiogenic therapies.
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| 2. |
- Bravi, Luca, et al.
(författare)
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Sulindac metabolites decrease cerebrovascular malformations in CCM3-knockout mice
- 2015
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 112:27, s. 8421-8426
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral cavernous malformation (CCM) is a disease of the central nervous system causing hemorrhage-prone multiple lumen vascular malformations and very severe neurological consequences. At present, the only recommended treatment of CCM is surgical. Because surgery is often not applicable, pharmacological treatment would be highly desirable. We describe here a murine model of the disease that develops after endothelial-cell-selective ablation of the CCM3 gene. We report an early, cell-autonomous, Wnt-receptor-independent stimulation of beta-catenin transcription activity in CCM3-deficient endothelial cells both in vitro and in vivo and a triggering of a beta-catenin-driven transcription program that leads to endothelial-tomesenchymal transition. TGF-beta/BMP signaling is then required for the progression of the disease. We also found that the anti-inflammatory drugs sulindac sulfide and sulindac sulfone, which attenuate beta-catenin transcription activity, reduce vascular malformations in endothelial CCM3-deficient mice. This study opens previously unidentified perspectives for an effective pharmacological therapy of intracranial vascular cavernomas.
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| 3. |
- Cardellini, Jacopo, et al.
(författare)
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Probing the coverage of nanoparticles by biomimetic membranes through nanoplasmonics
- 2023
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 640, s. 100-109
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Tidskriftsartikel (refereegranskat)abstract
- Although promising for biomedicine, the clinical translation of inorganic nanoparticles (NPs) is limited by low biocompatibility and stability in biological fluids. A common strategy to circumvent this drawback consists in disguising the active inorganic core with a lipid bilayer coating, reminiscent of the structure of the cell membrane to redefine the chemical and biological identity of NPs. While recent reports introduced membrane-coating procedures for NPs, a robust and accessible method to quantify the integrity of the bilayer coverage is not yet available. To fill this gap, we prepared SiO2 nanoparticles (SiO2NPs) with different membrane coverage degrees and monitored their interaction with AuNPs by combining microscopic, scattering, and optical techniques. The membrane-coating on SiO2NPs induces spontaneous clustering of AuNPs, whose extent depends on the coating integrity. Remarkably, we discovered a linear correlation between the membrane coverage and a spectral descriptor for the AuNPs’ plasmonic resonance, spanning a wide range of coating yields. These results provide a fast and cost-effective assay to monitor the compatibilization of NPs with biological environments, essential for bench tests and scale-up. In addition, we introduce a robust and scalable method to prepare SiO2NPs/AuNPs hybrids through spontaneous self-assembly, with a high-fidelity structural control mediated by a lipid bilayer.
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| 4. |
- Cuttano, Roberto, et al.
(författare)
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KLF4 is a key determinant in the development and progression of cerebral cavernous malformations
- 2016
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Ingår i: EMBO Molecular Medicine. - : EMBO. - 1757-4676 .- 1757-4684. ; 8:1, s. 6-24
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral cavernous malformations (CCMs) are vascular malformations located within the central nervous system often resulting in cerebral hemorrhage. Pharmacological treatment is needed, since current therapy is limited to neurosurgery. Familial CCM is caused by loss-of-function mutations in any of Ccm1, Ccm2, and Ccm3 genes. CCM cavernomas are lined by endothelial cells (ECs) undergoing endothelial-to-mesenchymal transition (EndMT). This switch in phenotype is due to the activation of the transforming growth factor beta/bone morphogenetic protein (TGFb/BMP) signaling. However, the mechanism linking Ccm gene inactivation and TGFb/ BMP-dependent EndMT remains undefined. Here, we report that Ccm1 ablation leads to the activation of a MEKK3-MEK5-ERK5MEF2 signaling axis that induces a strong increase in Kruppel-like factor 4 (KLF4) in ECs in vivo. KLF4 transcriptional activity is responsible for the EndMT occurring in CCM1-null ECs. KLF4 promotes TGFb/BMP signaling through the production of BMP6. Importantly, in endothelial-specific Ccm1 and Klf4 double knockout mice, we observe a strong reduction in the development of CCM and mouse mortality. Our data unveil KLF4 as a therapeutic target for CCM.
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| 5. |
- Giampietro, Costanza, et al.
(författare)
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The actin-binding protein EPS8 binds VE-cadherin and modulates YAP localization and signaling
- 2015
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Ingår i: Journal of Cell Biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 211:6, s. 1177-1192
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial (VE)-cadherin transfers intracellular signals contributing to vascular hemostasis. Signaling through VE-cadherin requires association and activity of different intracellular partners. Yes-associated protein (YAP)/TAZ transcriptional cofactors are important regulators of cell growth and organ size. We show that EPS8, a signaling adapter regulating actin dynamics, is a novel partner of VE-cadherin and is able to modulate YAP activity. By biochemical and imaging approaches, we demonstrate that EPS8 associates with the VE-cadherin complex of remodeling junctions promoting YAP translocation to the nucleus and transcriptional activation. Conversely, in stabilized junctions, 14-3-3-YAP associates with the VE-cadherin complex, whereas Eps8 is excluded. Junctional association of YAP inhibits nuclear translocation and inactivates its transcriptional activity both in vitro and in vivo in Eps8-null mice. The absence of Eps8 also increases vascular permeability in vivo, but did not induce other major vascular defects. Collectively, we identified novel components of the adherens junction complex, and we introduce a novel molecular mechanism through which the VE-cadherin complex controls YAP transcriptional activity.
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| 6. |
- Kakogiannos, Nikolaos, et al.
(författare)
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JAM-A Acts via C/EBP-alpha to Promote Claudin-5 Expression and Enhance Endothelial Barrier Function
- 2020
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Ingår i: Circulation Research. - : Lippincott Williams & Wilkins. - 0009-7330 .- 1524-4571. ; 127:8, s. 1056-1073
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: Intercellular tight junctions are crucial for correct regulation of the endothelial barrier. Their composition and integrity are affected in pathological contexts, such as inflammation and tumor growth. JAM-A (junctional adhesion molecule A) is a transmembrane component of tight junctions with a role in maintenance of endothelial barrier function, although how this is accomplished remains elusive.Objective: We aimed to understand the molecular mechanisms through which JAM-A expression regulates tight junction organization to control endothelial permeability, with potential implications under pathological conditions.Methods and Results: Genetic deletion of JAM-A in mice significantly increased vascular permeability. This was associated with significantly decreased expression of claudin-5 in the vasculature of various tissues, including brain and lung. We observed that C/EBP-α (CCAAT/enhancer-binding protein-α) can act as a transcription factor to trigger the expression of claudin-5 downstream of JAM-A, to thus enhance vascular barrier function. Accordingly, gain-of-function for C/EBP-α increased claudin-5 expression and decreased endothelial permeability, as measured by the passage of fluorescein isothiocyanate (FITC)-dextran through endothelial monolayers. Conversely, C/EBP-α loss-of-function showed the opposite effects of decreased claudin-5 levels and increased endothelial permeability. Mechanistically, JAM-A promoted C/EBP-α expression through suppression of β-catenin transcriptional activity, and also through activation of EPAC (exchange protein directly activated by cAMP). C/EBP-α then directly binds the promoter of claudin-5 to thereby promote its transcription. Finally, JAM-A–C/EBP-α–mediated regulation of claudin-5 was lost in blood vessels from tissue biopsies from patients with glioblastoma and ovarian cancer.Conclusions: We describe here a novel role for the transcription factor C/EBP-α that is positively modulated by JAM-A, a component of tight junctions that acts through EPAC to up-regulate the expression of claudin-5, to thus decrease endothelial permeability. Overall, these data unravel a regulatory molecular pathway through which tight junctions limit vascular permeability. This will help in the identification of further therapeutic targets for diseases associated with endothelial barrier dysfunction.
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| 7. |
- Lampugnani, Maria Grazia, et al.
(författare)
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Vascular Endothelial (VE)-Cadherin, Endothelial Adherens Junctions, and Vascular Disease
- 2018
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Ingår i: Cold Spring Harbor Perspectives in Biology. - : COLD SPRING HARBOR LAB PRESS, PUBLICATIONS DEPT. - 1943-0264. ; 10:10
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Tidskriftsartikel (refereegranskat)abstract
- Endothelial cell - cell adherens junctions (AJs) supervise fundamental vascular functions, such as the control of permeability and transmigration of circulating leukocytes, and the maintenance of existing vessels and formation of new ones. These processes are often dysregulated in pathologies. However, the evidence that links dysfunction of endothelial AJs to human pathologies is mostly correlative. In this review, we present an update of the molecular organization of AJ complexes in endothelial cells (ECs) that is mainly based on observations from experimental models. Furthermore, we report in detail on a human pathology, cerebral cavernous malformation (CCM), which is initiated by loss-of-function mutations in the genes that encode the three cytoplasmic components of AJs (CCM1, CCM2, and CCM3). At present, these represent a unique example of mutations in components of endothelial AJs that cause human disease. We describe also how studies into the defects of AJs in CCM are shedding light on the crucial regulatory mechanisms and signaling activities of these endothelial structures. Although these observations are specific for CCM, they support the concept that dysfunction of endothelial AJs can directly contribute to human pathologies.
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| 8. |
- Morini, Marco F., et al.
(författare)
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VE-Cadherin-Mediated Epigenetic Regulation of Endothelial Gene Expression
- 2018
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Ingår i: Circulation Research. - : LIPPINCOTT WILLIAMS & WILKINS. - 0009-7330 .- 1524-4571. ; 122:2, s. 231-245
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: The mechanistic foundation of vascular maturation is still largely unknown. Several human pathologies are characterized by deregulated angiogenesis and unstable blood vessels. Solid tumors, for instance, get their nourishment from newly formed structurally abnormal vessels which present wide and irregular interendothelial junctions. Expression and clustering of the main endothelial-specific adherens junction protein, VEC (vascular endothelial cadherin), upregulate genes with key roles in endothelial differentiation and stability.Objective: We aim at understanding the molecular mechanisms through which VEC triggers the expression of a set of genes involved in endothelial differentiation and vascular stabilization.Methods and Results: We compared a VEC-null cell line with the same line reconstituted with VEC wild-type cDNA. VEC expression and clustering upregulated endothelial-specific genes with key roles in vascular stabilization including claudin-5, vascular endothelial-protein tyrosine phosphatase (VE-PTP), and von Willebrand factor (vWf). Mechanistically, VEC exerts this effect by inhibiting polycomb protein activity on the specific gene promoters. This is achieved by preventing nuclear translocation of FoxO1 (Forkhead box protein O1) and beta-catenin, which contribute to PRC2 (polycomb repressive complex-2) binding to promoter regions of claudin-5, VE-PTP, and vWf. VEC/beta-catenin complex also sequesters a core subunit of PRC2 (Ezh2 [enhancer of zeste homolog 2]) at the cell membrane, preventing its nuclear translocation. Inhibition of Ezh2/VEC association increases Ezh2 recruitment to claudin-5, VE-PTP, and vWf promoters, causing gene downregulation. RNA sequencing comparison of VEC-null and VEC-positive cells suggested a more general role of VEC in activating endothelial genes and triggering a vascular stability-related gene expression program. In pathological angiogenesis of human ovarian carcinomas, reduced VEC expression paralleled decreased levels of claudin-5 and VE-PTP.Conclusions: These data extend the knowledge of polycomb-mediated regulation of gene expression to endothelial cell differentiation and vessel maturation. The identified mechanism opens novel therapeutic opportunities to modulate endothelial gene expression and induce vascular normalization through pharmacological inhibition of the polycomb-mediated repression system.
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| 9. |
- Savorani, Cecilia, et al.
(författare)
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A dual role of YAP in driving TGF beta-mediated endothelial-to-mesenchymal transition
- 2021
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Ingår i: Journal of Cell Science. - : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 134:15
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Tidskriftsartikel (refereegranskat)abstract
- Endothelial-to-mesenchymal transition (EndMT) is the biological process through which endothelial cells transdifferentiate into mesenchymal cells. During embryo development, EndMT regulates endocardial cushion formation via TGF beta/BMP signaling. In adults, EndMT is mainly activated during pathological conditions. Hence, it is necessary to characterize molecular regulators cooperating with TGF beta signaling in driving EndMT, to identify potential novel therapeutic targets to treat these pathologies. Here, we studied YAP, a transcriptional co-regulator involved in several biological processes, including epithelial-to-mesenchymal transition (EMT). As EndMT is the endothelial-specific form of EMT, and YAP (herein referring to YAP1) and TGF beta signaling cross-talk in other contexts, we hypothesized that YAP contributes to EndMT by modulating TGF beta signaling. We demonstrate that YAP is required to trigger TGF beta-induced EndMT response, specifically contributing to SMAD3-driven EndMT early gene transcription. We provide novel evidence that YAP acts as SMAD3 transcriptional co-factor and prevents GSK3 beta-mediated SMAD3 phosphorylation, thus protecting SMAD3 from degradation. YAP is therefore emerging as a possible candidate target to inhibit pathological TGF beta-induced EndMT at early stages.
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