scholarly journals The potassium channel Kcne3 is a VEGFA-inducible gene selectively expressed by vascular endothelial tip cells

Angiogenesis ◽  
2019 ◽  
Vol 23 (2) ◽  
pp. 179-192 ◽  
Author(s):  
Ron A. Deckelbaum ◽  
Ivan B. Lobov ◽  
Eunice Cheung ◽  
Gabor Halasz ◽  
Saathyaki Rajamani ◽  
...  
Keyword(s):  
Transcriptional Profiling ◽  
Vascular Endothelial ◽  
Cell Type ◽  
Tip Cell ◽  
Cell Specificity ◽  
Retinal Angiogenesis ◽  
Endothelial Growth Factor ◽  
Tip Cells ◽  
Early Phases ◽  
Inducible Gene

AbstractAngiogenesis is largely driven by motile endothelial tip-cells capable of invading avascular tissue domains and enabling new vessel formation. Highly responsive to Vascular Endothelial Growth-Factor-A (VEGFA), endothelial tip-cells also suppress angiogenic sprouting in adjacent stalk cells, and thus have been a primary therapeutic focus in addressing neovascular pathologies. Surprisingly, however, there remains a paucity of specific endothelial tip-cell markers. Here, we employ transcriptional profiling and a lacZ reporter allele to identify Kcne3 as an early and selective endothelial tip-cell marker in multiple angiogenic contexts. In development, Kcne3 expression initiates during early phases of angiogenesis (E9) and remains specific to endothelial tip-cells, often adjacent to regions expressing VEGFA. Consistently, Kcne3 activation is highly responsive to exogenous VEGFA but maintains tip-cell specificity throughout normal retinal angiogenesis. We also demonstrate endothelial tip-cell selectivity of Kcne3 in several injury and tumor models. Together, our data show that Kcne3 is a unique marker of sprouting angiogenic tip-cells and offers new opportunities for investigating and targeting this cell type.

scholarly journals A VEGF reaction-diffusion mechanism that selects variable densities of endothelial tip cells

2019 ◽  
Author(s):  
W. Bedell ◽  
A. D. Stroock
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Endothelial Cells ◽  
Growth Factor ◽  
Production Rate ◽  
Cell Selection ◽  
Vascular Endothelial ◽  
Tip Cell ◽  
Hypothetical Mechanism ◽  
Endothelial Growth Factor ◽  
Tip Cells

AbstractThe patterned differentiation of endothelial cells into tip and stalk cells represents an important step in the process of angiogenic sprouting. Vascular biologists hypothesize that changes in the density and overall structure of the vasculature can be traced in part to changes in the number of tip cells selected in the endothelium prior to sprout formation. However, the dominant hypotheses for tip cell selection invoke lateral inhibition via Notch; this juxtacrine mechanism predicts that a fixed fraction of endothelial cells become tip cells through a pattern-forming instability. Here, we present and analyze a hypothetical mechanism for tip cell selection that is based on endothelial competition for diffusible vascular endothelial growth factor (VEGF); this mechanism predicts that variable densities of tip cells emerge depending on the local (paracrine) production rate of VEGF. First, we hypothesize a network of VEGF signaling and trafficking based on previous experimental findings that could allow internalization of VEGF to occur with positive feedback. We formalize the hypothesis into a set of nonlinear ordinary differential equations and perform linear stability analysis to elucidate a general criterion for tip cell pattern formation under the mechanism. We use numerical integration to explore the nonlinear dynamics and final steady-states of tip cell patterns under this mechanism; the observed density of tip cells can be tuned from 10% to 84%. We conclude with proposals of future experiments and computational studies to explore how competitive consumption of diffusible VEGF may play a role in determining vascular structure.Statement of SignificanceThe patterned differentiation of endothelial cells into tip and stalk cells represents an important step in the process of blood vessel growth. Vascular biologists hypothesize that changes in the density and overall structure of the vasculature can be traced in part to changes in the number of tip cells selected during angiogenesis. However, the dominant hypotheses for tip cell selection predict that a locally fixed fraction of endothelial cells become tip cells following stimulation by vascular endothelial growth factor (VEGF). Here, we present and analyze a hypothetical mechanism for tip cell selection based on endothelial competition for diffusible VEGF; this mechanism predicts that variable densities of tip cells emerge depending on the local production rate of VEGF.

scholarly journals Vascular Endothelial Growth Factor Signaling in Models of Oxygen-Induced Retinopathy: Insights Into Mechanisms of Pathology in Retinopathy of Prematurity

2021 ◽  
Vol 9 ◽  
Author(s):  
Aniket Ramshekar ◽  
M. Elizabeth Hartnett
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Retinopathy Of Prematurity ◽  
Neuronal Development ◽  
Growth Factor Signaling ◽  
Vascular Endothelial ◽  
Vegf Signaling ◽  
Oxygen Induced Retinopathy ◽  
Retinal Angiogenesis ◽  
Endothelial Growth Factor

Retinopathy of prematurity (ROP) is a leading cause of blindness in children worldwide. Blindness can occur from retinal detachment caused by pathologic retinal angiogenesis into the vitreous, termed intravitreal neovascularization (IVNV). Although agents that interfere with the bioactivity of vascular endothelial growth factor (VEGF) are now used to treat IVNV, concerns exist regarding the identification of optimal doses of anti-VEGF for individual infants and the effect of broad VEGF inhibition on physiologic angiogenesis in external organs or in the retina of a preterm infant. Therefore, it is important to understand VEGF signaling in both physiologic and pathologic angiogenesis in the retina. In this manuscript, we review the role of receptors that interact with VEGF in oxygen-induced retinopathy (OIR) models that represent features of ROP pathology. Specifically, we discuss our work regarding the regulation of VEGFR2 signaling in retinal endothelial cells to not only reduce severe ROP but also facilitate physiologic retinal vascular and neuronal development.

scholarly journals A Fairy Chemical Suppresses Retinal Angiogenesis as a HIF Inhibitor

Biomolecules ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1405
Author(s):  
Deokho Lee ◽  
Yukihiro Miwa ◽  
Jing Wu ◽  
Chiho Shoda ◽  
Heonuk Jeong ◽  
...  
Keyword(s):  
Hypoxia Inducible Factor ◽  
Inhibitory Effect ◽  
Retinal Neovascularization ◽  
Vascular Endothelial ◽  
Vegf Mrna ◽  
Oxygen Induced Retinopathy ◽  
Hypoxic Conditions ◽  
Chronic Therapy ◽  
Retinal Angiogenesis ◽  
Endothelial Growth Factor

Neovascular retinal degeneration is a leading cause of blindness in advanced countries. Anti-vascular endothelial growth factor (VEGF) drugs have been used for neovascular retinal diseases; however, anti-VEGF drugs may cause the development of chorioretinal atrophy in chronic therapy as they affect the physiological amount of VEGF needed for retinal homeostasis. Hypoxia-inducible factor (HIF) is a transcription factor inducing VEGF expression under hypoxic and other stress conditions. Previously, we demonstrated that HIF was involved with pathological retinal angiogenesis in murine models of oxygen-induced retinopathy (OIR), and pharmacological HIF inhibition prevented retinal neovascularization by reducing an ectopic amount of VEGF. Along with this, we attempted to find novel effective HIF inhibitors. Compounds originally isolated from mushroom-forming fungi were screened for prospective HIF inhibitors utilizing cell lines of 3T3, ARPE-19 and 661W. A murine OIR model was used to examine the anti-angiogenic effects of the compounds. As a result, 2-azahypoxanthine (AHX) showed an inhibitory effect on HIF activation and suppressed Vegf mRNA upregulation under CoCl2-induced pseudo-hypoxic conditions. Oral administration of AHX significantly suppressed retinal neovascular tufts in the OIR model. These data suggest that AHX could be a promising anti-angiogenic agent in retinal neovascularization by inhibiting HIF activation.

scholarly journals Transcription of Inflammatory Cytokine TNFα is Upregulated in Retinal Angiogenesis under Hyperoxia

2016 ◽  
Vol 39 (2) ◽  
pp. 573-583
Author(s):  
Yuxi Feng ◽  
Shalini Gross ◽  
Anupriya Chatterjee ◽  
Yumei Wang ◽  
Jihong Lin ◽  
...  
Keyword(s):  
Underlying Mechanism ◽  
Vascular Endothelial ◽  
Vascular Morphology ◽  
Oxygen Induced Retinopathy ◽  
Avascular Zone ◽  
Deep Layers ◽  
Retinal Angiogenesis ◽  
Model C ◽  
Endothelial Growth Factor ◽  
Angiopoietin 1

Background/Aims: Hypoxia induces angiogenesis while hyperoxia promotes vasoregression in the retina. We investigated herein the effect of prolonged hyperoxia on retinal angiogenesis and the underlying mechanism in an oxygen-induced retinopathy (OIR) model. Methods: Vascular morphology was quantified in whole-mount retina from the mice subjected to the conventional OIR model (c-OIR) or the OIR model with prolonged hyperoxia (p-OIR). Expressions of genes related to angiogenesis were determined by real-time PCR. Results: p-OIR retinas showed few intraretinal neovascular tufts at the border of avascular zones, lacking preretinal neovascularization, whereas c-OIR retinas had numerous preretinal neovascularizations. p-OIR retinas demonstrated outgrowth of capillaries in the deep layers despite persistent hyperoxia and possess a larger avascular zone compared with the c-OIR retinas. The capillaries in the p-OIR retinas were well-formed in contrast to those in the c-OIR retinas. p-OIR retinas expressed significantly higher TNFα (∼4 fold) than c-OIR retinas. The expression of vascular endothelial growth factor, Erythropoietin, Angiopoietin 1 and 2 remained unchanged. Conclusion: Our data demonstrate that TNFα transcription is increased in hyperoxia-promoted retinal angiogenesis, implicating it, in association with low VEGF levels, as a possible proponent in retinal angiogenesis under hyperoxia.

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 PLD1-dependent PKCγ activation downstream to Src is essential for the development of pathologic retinal neovascularization

Blood ◽  
2010 ◽  
Vol 116 (8) ◽  
pp. 1377-1385 ◽  
Author(s):  
Qiuhua Zhang ◽  
Dong Wang ◽  
Venkatesh Kundumani-Sridharan ◽  
Laxmisilpa Gadiparthi ◽  
Dianna A. Johnson ◽  
...  
Keyword(s):  
Tube Formation ◽  
Dominant Negative ◽  
Retinal Neovascularization ◽  
Endothelial Cell Migration ◽  
Microvascular Endothelial Cell ◽  
Dominant Negative Mutant ◽  
Vascular Endothelial ◽  
Retinal Angiogenesis ◽  
Microvascular Endothelial ◽  
Endothelial Growth Factor

Abstract Vascular endothelial growth factor (VEGF) appears to be an important mediator of pathologic retinal angiogenesis. In understanding the mechanisms of pathologic retinal neovascularization, we found that VEGF activates PLD1 in human retinal microvascular endothelial cells, and this event is dependent on Src. In addition, VEGF activates protein kinase C-γ (PKCγ) via Src-dependent PLD1 stimulation. Inhibition of Src, PLD1, or PKCγ via pharmacologic, dominant negative mutant, or siRNA approaches significantly attenuated VEGF-induced human retinal microvascular endothelial cell migration, proliferation, and tube formation. Hypoxia also induced Src-PLD1-PKCγ signaling in retina, leading to retinal neovascularization. Furthermore, siRNA-mediated down-regulation of VEGF inhibited hypoxia-induced Src-PLD1-PKCγ activation and neovascularization. Blockade of Src-PLD1-PKCγ signaling via the siRNA approach also suppressed hypoxia-induced retinal neovascularization. Thus, these observations demonstrate, for the first time, that Src-dependent PLD1-PKCγ activation plays an important role in pathologic retinal angiogenesis.

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