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 Immunoelectron microscopy of endothelial cells in rat incisor suggests that most basement membrane components are produced by young cells, whereas heparan sulfate proteoglycan is produced by both young and old cells.

1988 ◽  
Vol 36 (7) ◽  
pp. 763-773 ◽  
Author(s):  
I C Murray ◽  
C P Leblond
Keyword(s):  
Endothelial Cells ◽  
Basement Membrane ◽  
Heparan Sulfate ◽  
Collagen Iv ◽  
Heparan Sulfate Proteoglycan ◽  
Sulfate Proteoglycan ◽  
Incisor Tooth ◽  
Rat Incisor ◽  
Membrane Components ◽  
Basement Membrane Components

When periodontal capillaries of rat incisor tooth were immunostained for four basement membrane components (laminin, collagen IV, fibronectin, heparan sulfate proteoglycan), all four were detected in the secretory organelles of endothelial cells located within 3 mm of the tooth's proximal end, but only the proteoglycan was observed in cells located 4 mm away and beyond (Experiment I). [3H]-Thymidine autoradiography revealed that the endothelial cells located at the tooth's proximal end were young and actively dividing, whereas those located 4 mm or more away were older and generally quiescent (Experiment II). Since immunostaining of a cell's secretory organelles for a given substance indicates production of this substance, the first experiment shows that endothelial cells at the proximal end produce the four basement membrane components. The second experiment discloses that these cells are young. As for the endothelial cells located 4 mm or more beyond the proximal end, the first experiment reveals that they produce only heparan sulfate proteoglycan, while the second shows that they are relatively old. Production of laminin, collagen IV, and fibronectin only by young cells implies that these substances are long-lived and stable components of basement membrane, whereas production of the proteoglycan by both young and old cells implies that it is labile and continually replaced.

scholarly journals The endosomal RIN2/Rab5C machinery prevents VEGFR2 degradation to control gene expression and tip cell identity during angiogenesis

Angiogenesis ◽  
2021 ◽  
Author(s):  
Lanette Kempers ◽  
Yuki Wakayama ◽  
Ivo van der Bijl ◽  
Charita Furumaya ◽  
Iris M. De Cuyper ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Target Genes ◽  
Cell Formation ◽  
Stalk Cell ◽  
Vegf Receptor ◽  
Tip Cell ◽  
Sprouting Angiogenesis ◽  
Vegf Signaling

AbstractSprouting angiogenesis is key to many pathophysiological conditions, and is strongly regulated by vascular endothelial growth factor (VEGF) signaling through VEGF receptor 2 (VEGFR2). Here we report that the early endosomal GTPase Rab5C and its activator RIN2 prevent lysosomal routing and degradation of VEGF-bound, internalized VEGFR2 in human endothelial cells. Stabilization of endosomal VEGFR2 levels by RIN2/Rab5C is crucial for VEGF signaling through the ERK and PI3-K pathways, the expression of immediate VEGF target genes, as well as specification of angiogenic ‘tip’ and ‘stalk’ cell phenotypes and cell sprouting. Using overexpression of Rab mutants, knockdown and CRISPR/Cas9-mediated gene editing, and live-cell imaging in zebrafish, we further show that endosomal stabilization of VEGFR2 levels is required for developmental angiogenesis in vivo. In contrast, the premature degradation of internalized VEGFR2 disrupts VEGF signaling, gene expression, and tip cell formation and migration. Thus, an endosomal feedforward mechanism maintains receptor signaling by preventing lysosomal degradation, which is directly linked to the induction of target genes and cell fate in collectively migrating cells during morphogenesis.

Role of the matrixin MMP-2 in multicellular organization of adipocytes cultured in basement membrane components

1997 ◽  
Vol 272 (3) ◽  
pp. C937-C949 ◽  
Author(s):  
L. M. Brown ◽  
H. L. Fox ◽  
S. A. Hazen ◽  
K. F. LaNoue ◽  
S. R. Rannels ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Basement Membrane ◽  
Conditioned Medium ◽  
Morphological Changes ◽  
Cluster Formation ◽  
Three Dimensional ◽  
Matrix Metalloproteinase 2 ◽  
Matrix Remodeling ◽  
Gelatinase Activity ◽  
Membrane Components

Primary rat adipocytes cultured in basement membrane component gels migrated and organized into large, three-dimensional, multicellular clusters. Gross morphological changes seen during this reorganization are described. The rate of cluster formation decreased with age of the rats and was stimulated by insulin in older, but not in younger rats. Echistatin, a disintegrin, partially inhibited the formation of multicellular clusters in a concentration-dependent fashion (50% inhibitory concentration approximately 10 nM). The original extracellular matrix was initially remodeled and eventually destroyed by the time large multicellular clusters were observed. This implied that one or more matrix-degrading protease(s) were being secreted. Adipocyte-conditioned medium was found to contain a divalent cation-sensitive gelatinase activity at approximately 72 and/or approximately 62 kDa. The elution profile of this activity from gelatin-Sepharose 4B was similar to matrix metalloproteinase 2 (MMP-2, a 72-kDa matrixin with a 62-kDa mature form), and the dimethyl sulfoxide eluant from these columns contained MMP-2 immunoreactivity. MMP-2 concentration and activity were greater in conditioned medium from young than from older animals; however, insulin did not affect the amount of MMP-2 in adipocyte-conditioned media. The matrixin inhibitor 1,10-phenanthroline not only blocked gelatinase activity in zymograms but also prevented extracellular matrix remodeling and destruction, as well as adipocyte migration and the formation of cell-cell contacts in adipocyte cultures. These observations are consistent with the hypothesis that the matrixin MMP-2 is secreted by adipocytes. Whereas matrixin activity alone may not be sufficient for the formation of multicellular clusters, the data indicate that it may have a requisite role in this process.

scholarly journals Myosin II activity is not required for Drosophila tracheal branching morphogenesis

2017 ◽  
Author(s):  
Amanda Ochoa-Espinosa ◽  
Stefan Harmansa ◽  
Emmanuel Caussinus ◽  
Markus Affolter
Keyword(s):  
Cell Migration ◽  
Myosin Ii ◽  
Branching Morphogenesis ◽  
Stalk Cell ◽  
Germ Band ◽  
Tracheal System ◽  
Tip Cell ◽  
Dorsal Branch ◽  
Cell Intercalation ◽  
Tip Cells

AbstractThe Drosophila tracheal system consists of an interconnected network of monolayered epithelial tubes that ensures oxygen transport in the larval and adult body. During tracheal dorsal branch (DB) development, individual DBs elongate as a cluster of cells, led by tip cells at the front and trailing cells in the rear. Branch elongation is accompanied by extensive cell intercalation and cell lengthening of the trailing stalk cells. While cell intercalation is governed by Myosin II (MyoII)-dependent forces during tissue elongation in the Drosophila embryo leading to germ-band extension, it remained unclear whether MyoII plays a similar active role during tracheal branch elongation and intercalation. Here, we use a nanobody-based approach to selectively knock-down MyoII in tracheal cells. Our data shows that despite the depletion of MyoII function, tip cells migration and stalk cell intercalation (SCI) proceeds at a normal rate. Therefore, our data confirms a model in which DB elongation and SCI in the trachea occurs as a consequence of tip cell migration, which produces the necessary forces for the branching process.Summary statementBranch elongation during Drosophila tracheal development mechanistically resembles MyoII-independent collective cell migration; tensile forces resulting from tip cell migration are reduced by cell elongation and passive stalk cell intercalation.AbbreviationsDBDorsal branchDCDorsal closureE-CadE-CadherinGBEGerm-band extensionMRLCMyosin regulatory light chainMyoIIMyosin IISCIstalk cell intercalationSqhSpaghetti squashSxllSex lethalTCTip cellTrTracheomere

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.

Interaction between Endothelial Cells and Basement Membrane Components

Pathobiology ◽  
1989 ◽  
Vol 57 (6) ◽  
pp. 315-323 ◽  
Author(s):  
Helma Rixen ◽  
Charles James Kirkpatrick ◽  
Ursula Schmitz ◽  
Dagmar Ruchatz ◽  
Christian Mittermayer
Keyword(s):  
Endothelial Cells ◽  
Basement Membrane ◽  
Membrane Components ◽  
Basement Membrane Components
Sign in / Sign up

Export Citation Format

Share Document