Microarray analysis of retinal endothelial tip cells identifies CXCR4 as a mediator of tip cell morphology and branching

Blood ◽  
2010 ◽  
Vol 115 (24) ◽  
pp. 5102-5110 ◽  
Author(s):  
Geraldine A. Strasser ◽  
Joshua S. Kaminker ◽  
Marc Tessier-Lavigne
Keyword(s):  
Microarray Analysis ◽  
Cell Morphology ◽  
Cell Function ◽  
Vascular System ◽  
Molecular Signaling ◽  
Vascular Patterning ◽  
Tip Cell ◽  
Stromal Cell Derived Factor ◽  
Angiopoietin 2 ◽  
Tip Cells

Abstract The development of the vertebrate vascular system is mediated by both genetic patterning of vessels and by angiogenic sprouting in response to hypoxia. Both of these processes depend on the detection of environmental guidance cues by endothelial cells. A specialized subtype of endothelial cell known as the tip cell is thought to be involved in the detection and response to these cues, but the molecular signaling pathways used by tip cells to mediate tissue vascularization remain largely uncharacterized. To identify genes critical to tip cell function, we have developed a method to isolate them using laser capture microdissection, permitting comparison of RNA extracted from endothelial tip cells with that of endothelial stalk cells using microarray analysis. Genes enriched in tip cells include ESM-1, angiopoietin-2, and SLP-76. CXCR4, a receptor for the chemokine stromal-cell derived factor-1, was also identified as a tip cell-enriched gene, and we provide evidence for a novel role for this receptor in mediating tip cell morphology and vascular patterning in the neonatal retina.

scholarly journals TNF primes endothelial cells for angiogenic sprouting by inducing a tip cell phenotype

Blood ◽  
2008 ◽  
Vol 111 (10) ◽  
pp. 4997-5007 ◽  
Author(s):  
Richard C. A. Sainson ◽  
Douglas A. Johnston ◽  
Henry C. Chu ◽  
Matthew T. Holderfield ◽  
Martin N. Nakatsu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Cell Function ◽  
Vascular Endothelial Cell ◽  
Immunofluorescent Staining ◽  
Cell Phenotype ◽  
Tip Cell ◽  
Tip Cells

Abstract Pathological angiogenesis associated with wound healing often occurs subsequent to an inflammatory response that includes the secretion of cytokines such as tumor necrosis factor (TNF). Controversy exists on the angiogenic actions of TNF, with it being generally proangiogenic in vivo, but antiangiogenic in vitro. We find that whereas continuous administration of TNF in vitro or in vivo inhibits angiogenic sprouting, a 2- to 3-day pulse stimulates angiogenesis by inducing an endothelial “tip cell” phenotype. TNF induces the known tip cell genes platelet-derived growth factor B (PDGFB) and vascular endothelial cell growth factor receptor-2 (VEGFR2), while at the same time blocking signaling through VEGFR2, thus delaying the VEGF-driven angiogenic response. Notch signaling regulates tip cell function, and we find that TNF also induces the notch ligand jagged-1, through an NFκB-dependent mechanism. Enrichment of jagged-1 in tip cells was confirmed by immunofluorescent staining as well as by laser capture microdissection/quantitative reverse-transcription–polymerase chain reaction (qRT-PCR) of tip cells sprouting in vitro. Thus, in angiogenesis, the temporal expression of TNF is critical: it delays angiogenesis initially by blocking signaling through VEGFR2, but in addition by inducing a tip cell phenotype through an NFκB-dependent pathway, it concomitantly primes endothelial cells (ECs) for sprouting once the initial inflammatory wave has passed.

Creation of retinal vein occlusion model in cynomolgusmonkeys and determination of its pathological features

2020 ◽  
Vol 17 ◽  
Author(s):  
Satoshi Inagaki ◽  
Masamitsu Shimazawa ◽  
Wataru Otsu ◽  
Tomoaki Araki ◽  
Yosuke Numata ◽  
...  
Keyword(s):  
Growth Factors ◽  
Retinal Vein Occlusion ◽  
Vascular System ◽  
Retinal Thickness ◽  
Chronic Phase ◽  
Vascular Leakage ◽  
Foveal Avascular Zone ◽  
Retinal Edema ◽  
Vein Occlusion ◽  
Angiopoietin 2

Objective: A retinal vein occlusion (RVO) is a relatively common retinal vascular disorder especially in the elder-ly. Many experiments have been performed on patients with a RVO but performing any type of experiments and especially longitudinal experiments on humans is difficult if not impossible on ethical grounds. Therefore, we have created a retinal vein occlusion (RVO) model by laser irradiation of cynomolgus monkeysafter an intravenous injection of rose bengal. Weevaluated the pathological changes of the retina, and the effects of ranibizumab, an anti-vascular endothelial growth factor (VEGF) antibody, on the characteristics of the RVO. Methods: The integrity of the vascular system was evaluated by fluorescein angiography (FA), and the retinal thickness and volume were determined by optical coherence tomography (OCT). The cytokines and growth factors in the aqueous humor were identified by multiplex profiling. Results: Our results showed that ranibizumab decreased the degree of vascular leakage and retinal edema at 1-3 days (acute phase) and 3-7 days (subacute phase), and suppressed foveal thinning at 28-42 days (chronic phase) after the laser irradia-tion. Ranibizumab also decreased the area of the foveal avascular zone, and the area was negatively and significantly corre-lated with the thickness of the ganglion cell layer (GCL) complex. Furthermore, ranibizumab reduced the increased expres-sion of VEGF in the aqueous humour, but did not affect the expressions of interleukin-6 (IL-6), monocyte chemotactic pro-tein-1 (MCP-1), angiopoietin-1 (ANG-1), or angiopoietin-2 (ANG-2).Thesefindings suggest that ranibizumab attenuates the retinal edema and subsequent retinal atrophy in partby neutralizing VEGF. However, other cytokines and growth factors were also affected by the ranibizumab which suggests that not only VEGF but also other unidentified agents might play a role in the pathogenesis of the RVO. Conclusion: We have created a non-human primate RVO model, which resembles the clinical RVO pathology. In this model, an injection of ranibizumab leads to a reduction in the vascular leakage and the retinal thickness and volume by blockingthe expression of VEGF. Our model might be useful for investigating the pathological mechanisms of RVOs and explore new therapeutic agents for RVO.

The histone acetyltransferase HBO1 (KAT7) promotes efficient tip cell sprouting during angiogenesis

Development ◽  
2021 ◽  
Author(s):  
Zoe L. Grant ◽  
Peter F. Hickey ◽  
Waruni Abeysekera ◽  
Lachlan Whitehead ◽  
Sabrina M. Lewis ◽  
...  
Keyword(s):  
Histone Acetyltransferase ◽  
Dynamic Changes ◽  
Cell Behaviour ◽  
Tip Cell ◽  
Sprouting Angiogenesis ◽  
A Genome ◽  
Vessel Growth ◽  
Intergenic Regions ◽  
Tip Cells

Blood vessel growth and remodelling are essential during embryonic development and disease pathogenesis. The diversity of endothelial cells (ECs) is transcriptionally evident and ECs undergo dynamic changes in gene expression during vessel growth and remodelling. Here, we investigated the role of the histone acetyltransferase HBO1 (KAT7), which is important for activating genes during development and histone H3 lysine 14 acetylation (H3K14ac). Loss of HBO1 and H3K14ac impaired developmental sprouting angiogenesis and reduced pathological EC overgrowth in the retinal endothelium. Single-cell RNA-sequencing of retinal ECs revealed an increased abundance of tip cells in Hbo1 deleted retinas, which lead to EC overcrowding in the retinal sprouting front and prevented efficient tip cell migration. We found that H3K14ac was highly abundant in the endothelial genome in both intra- and intergenic regions suggesting that the role of HBO1 is as a genome organiser that promotes efficient tip cell behaviour necessary for sprouting angiogenesis.

ENDOTHELIAL FUNCTION MODULATION AND CONTROL OF VASCULAR AND THROMBOTIC DISORDERS: EXPERIMENTAL RESULTS WITH A POLYDEOXY RIBONUCLEOTIDE AGENT DEFIBROTIDE

1987 ◽  
Author(s):  
A Kumar ◽  
J Fareed ◽  
W H Wehrmacher ◽  
D Hoppensteadt ◽  
O Ulutin ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Oral Administration ◽  
Cell Function ◽  
Vascular System ◽  
Ex Vivo ◽  
Smooth Muscles ◽  
Venous Stasis ◽  
Functional Protein ◽  
Endothelial Cell Function ◽  
Multiple Drugs

Numerous approaches with single and multiple drugs modulating protease cascade, platelet function and blood viscosity and to reduce blood lipids to manage thrombotic processes have been tried. Defibrotide, a polydeoxyribonucleotide, (Mr =17,000) offers a new approach to vascular and related thrombotic processes as it acts via modulation of endothelial cell function. We have used a primate model (Macaca mulatta) to study the endogenous action of this agent after the oral (10-25 mg/kg) and intravenous (5-10 mg/kg) administration. This agent produced no effect on clotting tests and ex vivo laboratory findings but rather it elevated the t-PA (antigen and functional), protein C (antigen and functional), prostacyclin and decreased thromboxane, 01.2-antiplasmin (functional) and t-PA inhibitor (functional) in both studies. These observations suggest that Defibrotide modulates endothelial function. Hepatic isolation in rabbits totally blocked the antithrombotic actions of Defibrotide suggesting that this agent is converted into an active product endogenously. Pretreatment of Defibrotide with nucleases also resulted in a complete loss of its actions. Defibrotide produced dose dependent antithrombotic actions in animal models (rabbit venous stasis and rat vena caval ligation) after either intravenous or oral administration. Blood pressure, heart rate, respiration and kidney function were not altered by it. No effect on bleeding time was noted in any studies. Upon oral administration this drug produced pharmacologic action after 2 hours whereas after intravenous administration, the action peaked at 30 minutes. Defibrotide exhibited cytoprotective effects towards endothelial lining of the vascular smooth muscles characterized by microscopic studies. In summary Defibrotide is an endothelial support agent whose multicomponent actions are primarily mediated via the physical and functional modulation of the endothelial cells in the vascular system.

scholarly journals Identification and functional analysis of endothelial tip cell–enriched genes

Blood ◽  
2010 ◽  
Vol 116 (19) ◽  
pp. 4025-4033 ◽  
Author(s):  
Raquel del Toro ◽  
Claudia Prahst ◽  
Thomas Mathivet ◽  
Geraldine Siegfried ◽  
Joshua S. Kaminker ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Basement Membrane ◽  
Cell Fate ◽  
Stalk Cell ◽  
Matrix Remodeling ◽  
Retinal Endothelial Cells ◽  
Tip Cell ◽  
Mouse Mutants ◽  
Membrane Components ◽  
Tip Cells

Abstract Sprouting of developing blood vessels is mediated by specialized motile endothelial cells localized at the tips of growing capillaries. Following behind the tip cells, endothelial stalk cells form the capillary lumen and proliferate. Expression of the Notch ligand Delta-like-4 (Dll4) in tip cells suppresses tip cell fate in neighboring stalk cells via Notch signaling. In DLL4+/− mouse mutants, most retinal endothelial cells display morphologic features of tip cells. We hypothesized that these mouse mutants could be used to isolate tip cells and so to determine their genetic repertoire. Using transcriptome analysis of retinal endothelial cells isolated from DLL4+/− and wild-type mice, we identified 3 clusters of tip cell–enriched genes, encoding extracellular matrix degrading enzymes, basement membrane components, and secreted molecules. Secreted molecules endothelial-specific molecule 1, angiopoietin 2, and apelin bind to cognate receptors on endothelial stalk cells. Knockout mice and zebrafish morpholino knockdown of apelin showed delayed angiogenesis and reduced proliferation of stalk cells expressing the apelin receptor APJ. Thus, tip cells may regulate angiogenesis via matrix remodeling, production of basement membrane, and release of secreted molecules, some of which regulate stalk cell behavior.

scholarly journals Tracheal tube fusion in Drosophila involves release of luminal exosomes from multivesicular bodies

2021 ◽  
Author(s):  
Carolina Camelo ◽  
Anna Koerte ◽  
Thea Jacobs ◽  
Peter Robin Hiesinger ◽  
Stefan Luschnig
Keyword(s):  
Tracheal Tube ◽  
Extracellular Vesicles ◽  
Multivesicular Bodies ◽  
Tracheal Lumen ◽  
Tracheal System ◽  
Tip Cell ◽  
Luminal Membrane ◽  
Lysosome Related Organelles ◽  
Tip Cells ◽  
Development Of Organs

Fusion of endothelial or epithelial tubes is essential for the development of organs like the vertebrate vasculature or the insect tracheal system, but the mechanisms underlying the formation of tubular connections (anastomoses) are not well understood. Tracheal tube fusion in Drosophila is mediated by tip cells that transform into lumenized toroids to connect adjacent tubes. This process depends on the Munc13-4 orthologue Staccato (Stac), which localizes to tip-cell-specific lysosome-related organelles (LROs). We show that tracheal LROs display features of multivesicular bodies (MVBs) and that the tracheal lumen contains membranous extracellular vesicles (EVs), a subset of which carries Stac/Munc13-4 and is associated with tracheal anastomosis sites. The presence of LROs and luminal Stac-EVs depends on the tip-cell-specific GTPase Arl3, suggesting that Stac-EVs derive from fusion of MVBs with the luminal membrane in tip cells during anastomosis formation. The GTPases Rab27 and Rab35 cooperate downstream of Arl3 to promote Stac-MVB formation and tube fusion. We propose that Stac-MVBs act as membrane reservoirs that facilitate lumen fusion in tip cells, in a process regulated by Arl3, Rab27, Rab35, and Stac/Munc13-4.

scholarly journals Tip cell-specific requirement for an atypical Gpr124- and Reck-dependent Wnt/β-catenin pathway during brain angiogenesis

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Benoit Vanhollebeke ◽  
Oliver A Stone ◽  
Naguissa Bostaille ◽  
Chris Cho ◽  
Yulian Zhou ◽  
...  
Keyword(s):  
Cell Function ◽  
Critical Role ◽  
Tip Cell ◽  
Signaling Complex ◽  
Mmp Inhibitor ◽  
Wnt Ligands ◽  
Multistep Process ◽  
Organ Specific ◽  
Sense And Respond ◽  
Brain Angiogenesis

Despite the critical role of endothelial Wnt/β-catenin signaling during central nervous system (CNS) vascularization, how endothelial cells sense and respond to specific Wnt ligands and what aspects of the multistep process of intra-cerebral blood vessel morphogenesis are controlled by these angiogenic signals remain poorly understood. We addressed these questions at single-cell resolution in zebrafish embryos. We identify the GPI-anchored MMP inhibitor Reck and the adhesion GPCR Gpr124 as integral components of a Wnt7a/Wnt7b-specific signaling complex required for brain angiogenesis and dorsal root ganglia neurogenesis. We further show that this atypical Wnt/β-catenin signaling pathway selectively controls endothelial tip cell function and hence, that mosaic restoration of single wild-type tip cells in Wnt/β-catenin-deficient perineural vessels is sufficient to initiate the formation of CNS vessels. Our results identify molecular determinants of ligand specificity of Wnt/β-catenin signaling and provide evidence for organ-specific control of vascular invasion through tight modulation of tip cell function.

Sign in / Sign up

Export Citation Format

Share Document