scholarly journals The Role of Heparan Sulfate and Neuropilin 2 in VEGFA Signaling in Human Endothelial Tip Cells and Non-Tip Cells during Angiogenesis In Vitro

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 926
Author(s):  
Marchien G. Dallinga ◽  
Yasmin I. Habani ◽  
Alinda W. M. Schimmel ◽  
Geesje M. Dallinga-Thie ◽  
Cornelis J. F. van Noorden ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Heparan Sulfate ◽  
Splice Variant ◽  
Cell Formation ◽  
Stalk Cell ◽  
Vegf Receptor ◽  
Tip Cell ◽  
Sprout Formation ◽  
Tip Cells

During angiogenesis, vascular endothelial growth factor A (VEGFA) regulates endothelial cell (EC) survival, tip cell formation, and stalk cell proliferation via VEGF receptor 2 (VEGFR2). VEGFR2 can interact with VEGFR2 co-receptors such as heparan sulfate proteoglycans (HSPGs) and neuropilin 2 (NRP2), but the exact roles of these co-receptors, or of sulfatase 2 (SULF2), an enzyme that removes sulfate groups from HSPGs and inhibits HSPG-mediated uptake of very low density lipoprotein (VLDL), in angiogenesis and tip cell biology are unknown. In the present study, we investigated whether the modulation of binding of VEGFA to VEGFR2 by knockdown of SULF2 or NRP2 affects sprouting angiogenesis, tip cell formation, proliferation of non-tip cells, and EC survival, or uptake of VLDL. To this end, we employed VEGFA splice variant 121, which lacks an HSPG binding domain, and VEGFA splice variant 165, which does have this domain, in in vitro models of angiogenic tip cells and vascular sprouting. We conclude that VEGFA165 and VEGFA121 have similar inducing effects on tip cells and sprouting in vitro, and that the binding of VEGFA165 to HSPGs in the extracellular matrix does not seem to play a role, as knockdown of SULF2 did not alter these effects. Co-binding of NRP2 appears to regulate VEGFA–VEGFR2-induced sprout initiation, but not tip cell formation. Finally, as the addition of VLDL increased sprout formation but not tip cell formation, and as VLDL uptake was limited to non-tip cells, our findings suggest that VLDL plays a role in sprout formation by providing biomass for stalk cell proliferation.

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.

scholarly journals Neuropilin-2 mediates VEGF-C–induced lymphatic sprouting together with VEGFR3

2010 ◽  
Vol 188 (1) ◽  
pp. 115-130 ◽  
Author(s):  
Yunling Xu ◽  
Li Yuan ◽  
Judy Mak ◽  
Luc Pardanaud ◽  
Maresa Caunt ◽  
...  
Keyword(s):  
Lymphatic Vessel ◽  
Vascular System ◽  
Lymph Vessel ◽  
Vegf Receptor ◽  
Antibody Treatment ◽  
Tip Cell ◽  
Factor C ◽  
Sprout Formation

Vascular sprouting is a key process-driving development of the vascular system. In this study, we show that neuropilin-2 (Nrp2), a transmembrane receptor for the lymphangiogenic vascular endothelial growth factor C (VEGF-C), plays an important role in lymphatic vessel sprouting. Blocking VEGF-C binding to Nrp2 using antibodies specifically inhibits sprouting of developing lymphatic endothelial tip cells in vivo. In vitro analyses show that Nrp2 modulates lymphatic endothelial tip cell extension and prevents tip cell stalling and retraction during vascular sprout formation. Genetic deletion of Nrp2 reproduces the sprouting defects seen after antibody treatment. To investigate whether this defect depends on Nrp2 interaction with VEGF receptor 2 (VEGFR2) and/or 3, we intercrossed heterozygous mice lacking one allele of these receptors. Double-heterozygous nrp2vegfr2 mice develop normally without detectable lymphatic sprouting defects. In contrast, double-heterozygote nrp2vegfr3 mice show a reduction of lymphatic vessel sprouting and decreased lymph vessel branching in adult organs. Thus, interaction between Nrp2 and VEGFR3 mediates proper lymphatic vessel sprouting in response to VEGF-C.

scholarly journals ERBB 2 signaling drives supporting cell proliferation in vitro and apparent supernumerary hair cell formation in vivo in the neonatal mouse cochlea

2018 ◽  
Vol 48 (10) ◽  
pp. 3299-3316 ◽  
Author(s):  
Jingyuan Zhang ◽  
Quan Wang ◽  
Dunia Abdul‐Aziz ◽  
Jonelle Mattiacio ◽  
Albert S. B. Edge ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Hair Cell ◽  
Cell Formation ◽  
Supporting Cell ◽  
Neonatal Mouse ◽  
Proliferation In Vitro

scholarly journals Prenatal inflammation impairs intestinal microvascular development through a TNF-dependent mechanism and predisposes newborn mice to necrotizing enterocolitis

2019 ◽  
Vol 317 (1) ◽  
pp. G57-G66 ◽  
Author(s):  
Xiaocai Yan ◽  
Elizabeth Managlia ◽  
Xiao-Di Tan ◽  
Isabelle G. De Plaen
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cell ◽  
Necrotizing Enterocolitis ◽  
Endothelial Cell Proliferation ◽  
Vegf Receptor ◽  
Fetal Serum ◽  
Prenatal Inflammation ◽  
Vegfr2 Signaling

Prenatal inflammation is a risk factor for necrotizing enterocolitis (NEC), and it increases intestinal injury in a rat NEC model. We previously showed that maldevelopment of the intestinal microvasculature and lack of vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) signaling play a role in experimental NEC. However, whether prenatal inflammation affects the intestinal microvasculature remains unknown. In this study, mouse dams were injected intraperitoneally with lipopolysaccharide (LPS) or saline at embryonic day 17. Neonatal intestinal microvasculature density, endothelial cell proliferation, and intestinal VEGF-A and VEGFR2 proteins were assessed in vivo. Maternal and fetal serum TNF concentrations were measured by ELISA. The impact of TNF on the neonatal intestinal microvasculature was examined in vitro and in vivo, and we determined whether prenatal LPS injection exacerbates experimental NEC via TNF. Here we found that prenatal LPS injection significantly decreased intestinal microvascular density, endothelial cell proliferation, and VEGF and VEGFR2 protein expression in neonatal mice. Prenatal LPS injection increased maternal and fetal serum levels of TNF. TNF decreased VEGFR2 protein in vitro in neonatal endothelial cells. Postnatal TNF administration in vivo decreased intestinal microvasculature density, endothelial cell proliferation, and VEGF and VEGFR2 protein expression and increased the incidence of severe NEC. These effects were ameliorated by stabilizing hypoxia-inducible factor-1α, the master regulator of VEGF. Furthermore, prenatal LPS injection significantly increased the incidence of severe NEC in our model, and the effect was dependent on endogenous TNF. Our study suggests that prenatal inflammation increases the susceptibility to NEC, downregulates intestinal VEGFR2 signaling, and affects perinatal intestinal microvascular development via a TNF mechanism. NEW & NOTEWORTHY This report provides new evidence that maternal inflammation decreases neonatal intestinal VEGF receptor 2 signaling and endothelial cell proliferation, impairs intestinal microvascular development, and predisposes neonatal mouse pups to necrotizing enterocolitis (NEC) through inflammatory cytokines such as TNF. Our data suggest that alteration of intestinal microvascular development may be a key mechanism by which premature infants exposed to prenatal inflammation are at risk for NEC and preserving the VEGF/VEGF receptor 2 signaling pathway may help prevent NEC development.

scholarly journals Robust and Scalable Angiogenesis Assay of Perfused 3D Human iPSC-Derived Endothelium for Anti-Angiogenic Drug Screening

2020 ◽  
Vol 21 (13) ◽  
pp. 4804
Author(s):  
Vincent van Duinen ◽  
Wendy Stam ◽  
Eva Mulder ◽  
Farbod Famili ◽  
Arie Reijerkerk ◽  
...  
Keyword(s):  
Drug Screening ◽  
Cell Formation ◽  
Cell Types ◽  
Culture Conditions ◽  
In Vitro Assays ◽  
Vegf Receptor ◽  
Screening Assay ◽  
Angiogenesis Assay

To advance pre-clinical vascular drug research, in vitro assays are needed that closely mimic the process of angiogenesis in vivo. Such assays should combine physiological relevant culture conditions with robustness and scalability to enable drug screening. We developed a perfused 3D angiogenesis assay that includes endothelial cells (ECs) from induced pluripotent stem cells (iPSC) and assessed its performance and suitability for anti-angiogenic drug screening. Angiogenic sprouting was compared with primary ECs and showed that the microvessels from iPSC-EC exhibit similar sprouting behavior, including tip cell formation, directional sprouting and lumen formation. Inhibition with sunitinib, a clinically used vascular endothelial growth factor (VEGF) receptor type 2 inhibitor, and 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO), a transient glycolysis inhibitor, both significantly reduced the sprouting of both iPSC-ECs and primary ECs, supporting that both cell types show VEGF gradient-driven angiogenic sprouting. The assay performance was quantified for sunitinib, yielding a minimal signal window of 11 and Z-factor of at least 0.75, both meeting the criteria to be used as screening assay. In conclusion, we have developed a robust and scalable assay that includes physiological relevant culture conditions and is amenable to screening of anti-angiogenic compounds.

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.

VEGFRs and Notch: a dynamic collaboration in vascular patterning

2009 ◽  
Vol 37 (6) ◽  
pp. 1233-1236 ◽  
Author(s):  
Lars Jakobsson ◽  
Katie Bentley ◽  
Holger Gerhardt
Keyword(s):  
Selection Process ◽  
Cell Formation ◽  
Computational Modelling ◽  
Stalk Cell ◽  
Cell Phenotype ◽  
Vegf Receptor ◽  
Cellular Mechanisms ◽  
Dynamic Interactions ◽  
Receptor System ◽  
Molecular Control

ECs (endothelial cells) in the developing vasculature are heterogeneous in morphology, function and gene expression. Inter-endothelial signalling via Dll4 (Delta-like 4) and Notch has recently emerged as a key regulator of endothelial heterogeneity, controlling arterial cell specification and tip versus stalk cell selection. During sprouting angiogenesis, tip cell formation is the default response to VEGF (vascular endothelial growth factor), whereas the stalk cell phenotype is acquired through Dll4/Notch-mediated lateral inhibition. Precisely how Notch signalling represses stalk cells from becoming tip cells remains unclear. Multiple components of the VEGFR (VEGF receptor) system are regulated by Notch, suggesting that quantitative differences in protein expression between adjacent ECs may provide key features in the formation of a functional vasculature. Computational modelling of this selection process in iterations, with experimental observation and validation greatly facilitates our understanding of the integrated processes at the systems level. We anticipate that the study of mosaic vascular beds of genetically modified ECs in dynamic interactions with wild-type ECs will provide a powerful tool for the investigation of the molecular control and cellular mechanisms of EC specification.

scholarly journals Endothelial Ca2+ oscillations reflect VEGFR signaling-regulated angiogenic capacity in vivo

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Yasuhiro Yokota ◽  
Hiroyuki Nakajima ◽  
Yuki Wakayama ◽  
Akira Muto ◽  
Koichi Kawakami ◽  
...  
Keyword(s):  
Stalk Cell ◽  
Vegf Receptor ◽  
Vascular Endothelial ◽  
Cardinal Vein ◽  
Sprouting Angiogenesis ◽  
Spatio Temporal ◽  
Endothelial Growth Factor ◽  
Tip Cells ◽  
Selection Of

Sprouting angiogenesis is a well-coordinated process controlled by multiple extracellular inputs, including vascular endothelial growth factor (VEGF). However, little is known about when and how individual endothelial cell (EC) responds to angiogenic inputs in vivo. Here, we visualized endothelial Ca2+ dynamics in zebrafish and found that intracellular Ca2+ oscillations occurred in ECs exhibiting angiogenic behavior. Ca2+ oscillations depended upon VEGF receptor-2 (Vegfr2) and Vegfr3 in ECs budding from the dorsal aorta (DA) and posterior cardinal vein, respectively. Thus, visualizing Ca2+ oscillations allowed us to monitor EC responses to angiogenic cues. Vegfr-dependent Ca2+ oscillations occurred in migrating tip cells as well as stalk cells budding from the DA. We investigated how Dll4/Notch signaling regulates endothelial Ca2+ oscillations and found that it was required for the selection of single stalk cell as well as tip cell. Thus, we captured spatio-temporal Ca2+ dynamics during sprouting angiogenesis, as a result of cellular responses to angiogenic inputs.

scholarly journals Knockdown of Fibromodulin Inhibits Proliferation and Migration of RPE Cell via the VEGFR2-AKT Pathway

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
He Hu ◽  
Shanshan Li ◽  
Jianqiao Li ◽  
Chao Huang ◽  
Fang Zhou ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Retinal Pigment ◽  
Cell Counting ◽  
Control Group ◽  
Vegf Receptor ◽  
Phosphorylated Akt ◽  
And Migration ◽  
Proliferation And Migration

Purpose. Recent research has provided novel insight into the function of fibromodulin (FMOD) in wound healing and angiogenesis. The role of FMOD in initiation of proliferative vitreoretinopathy (PVR) has not been studied. This study investigated the effect of FMOD on human retinal pigment epithelial (RPE) cell, which plays an essential role in the progression of PVR, and the possible mechanisms. Methods. Small interfering (si) RNA-based gene transfer technology was used to decrease FMOD expression and to study its effects on RPEs in vitro. Cell Counting Kit-8 assays, transwells, and flow cytometry analysis were used to measure cell proliferation, migration, cell cycle, and apoptosis. Western blot was used to measure expression of vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2), extracellular signal-related kinase 1/2 (ERK1/2), and phosphoinositide 3 kinase (PI3K/AKT). Results. After transfection of RPEs with a FMOD-specific siRNA, cell proliferation and migration were inhibited to the percentage of 65% ± 5% and 39% ± 10%, respectively, compared to the control group. Depletion of FMOD induced cell cycle arrest and apoptosis in RPE cells. Downregulation of VEGF, VEGFR2, and phosphorylated AKT (p-AKT) were detected in transfected RPEs. Conclusion. Depletion of FMOD selectively downregulated the expression of VEGF and VEGFR2 and inhibited the signaling pathway of AKT phosphorylation, which consequently inhibited the proliferation and migration of RPE Cell.

Abstract 368: Novel Role of Cofilin in Retinal Neovascularization

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Raj Kumar ◽  
Jagadish Janjanam ◽  
Nikhlesh K Singh ◽  
Gadiparthi N Rao
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cell ◽  
Cell Formation ◽  
Fiber Formation ◽  
Endothelial Cell Proliferation ◽  
Actin Stress Fiber ◽  
Dependent Manner ◽  
Tip Cell ◽  
Cofilin Phosphorylation ◽  
Retinal Endothelial Cell

Pak1 plays an important role in several cellular processes including cell migration, but its role in pathological angiogenesis is not known. Here we have determined its role in pathological retinal angiogenesis using Oxygen Induced Retinopathy (OIR) model. VEGFA induced Pak1 and its effector cofilin phosphorylation in time-dependent as well as p38β-dependent manner in HRMVECs. Depletion of the levels of any of these molecules inhibited VEGFA-induced HRMVECs F-actin stress fiber formation, migration, proliferation, sprouting, and tube formation. In accordance with these observations, hypoxia induced Pak1 and Cofilin phosphorylation with p38β being downstream to Pak1 and upstream to cofilin. Furthermore, Pak1 deficiency abolished hypoxia-induced p38β and cofilin phosphorylation and abrogated retinal endothelial cell proliferation, tip cell formation and neovascularization. In addition, siRNA-mediated downregulation of p38β or cofilin levels in WT mouse retina also diminished endothelial cell proliferation, tip cell formation and neovascularization. Together, these observations suggest that, while p38β-Pak1-cofilin axis is required for HRMVECs migration, proliferation, sprouting and tubulogenesis, Pak1-p38β-cofilin signaling is essential for hypoxia-induced retinal endothelial cell proliferation, tip cell formation and neovascularization.

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