Chronological Changes in Tip Cells during Sprouting Angiogenesis of Development of the Retinal Vasculature in Newborn Mice

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.

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Sprouting angiogenesis in human midterm uterus and fallopian tube is guided by endothelial tip cells

Anatomical Science International ◽

10.1007/s12565-012-0154-x ◽

2012 ◽

Vol 88 (1) ◽

pp. 25-30 ◽

Cited By ~ 11

Author(s):

M. C. Rusu ◽

A. G. M. Motoc ◽

F. Pop ◽

R. Folescu

Keyword(s):

Fallopian Tube ◽

Sprouting Angiogenesis ◽

Tip Cells

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

eLife ◽

10.7554/elife.08817 ◽

2015 ◽

Vol 4 ◽

Cited By ~ 31

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.

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Endothelial cell invasiveness is controlled by myosin IIA-dependent inhibition of Arp2/3 activity

10.1101/2020.09.08.287466 ◽

2020 ◽

Author(s):

Ana M. Figueiredo ◽

Pedro Barbacena ◽

Ana Russo ◽

Silvia Vaccaro ◽

Daniela Ramalho ◽

...

Keyword(s):

Endothelial Cell ◽

Focal Adhesions ◽

Sprouting Angiogenesis ◽

Dependent Inhibition ◽

Myosin Iia ◽

Maturation State ◽

Cell Invasiveness ◽

Cellular Protrusion ◽

Tip Cells ◽

New Strategies

AbstractSprouting angiogenesis is fundamental for development and contributes to multiple diseases, including cancer, diabetic retinopathy and cardiovascular diseases. Sprouting angiogenesis depends on the invasive properties of endothelial tip cells. However, there is very limited knowledge on the mechanisms that endothelial tip cells use to invade into tissues. Here, we prove that endothelial tip cells use long lamellipodia projections (LLPs) as the main cellular protrusion for invasion into non-vascular extracellular matrix. We show that LLPs and filopodia protrusions are balanced by myosin-IIA (MIIA) and actin-related protein 2/3 (Arp2/3) activity. Endothelial cell-autonomous ablation of MIIA promotes excessive LLPs formation in detriment of filopodia. Conversely, endothelial cell-autonomous ablation of Arp2/3 prevents LLPs development and leads to excessive filopodia formation. We further show that MIIA inhibits Rac1-dependent activation of Arp2/3, by regulating the maturation state of focal adhesions. Our discoveries establish the first comprehensive model of how endothelial tip cells regulate its protrusive activity and will pave the way towards new strategies to block invasive tip cells during sprouting angiogenesis.

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The Transcription Factor Complex LMO2/TAL1 Regulates Branching and Endothelial Cell Migration in Sprouting Angiogenesis

10.21203/rs.3.rs-384580/v1 ◽

2021 ◽

Author(s):

Yoshihiro Yamada ◽

Yi Zhong ◽

Shiho Miki ◽

Akiko Taura ◽

Terence Rabbitts

Keyword(s):

Endothelial Cells ◽

Transcription Factor ◽

Endothelial Cell ◽

Endothelial Cell Migration ◽

Angiogenic Switch ◽

Sprouting Angiogenesis ◽

Relative Paucity ◽

Angiopoietin 2 ◽

Tip Cells ◽

Transcription Factor Complex

Abstract The transcription factor complex, consisting of LMO2, TAL1/LYL1, and GATA2, plays an important role in capillary sprouting by regulating VEGFR2, DLL4, and angiopoietin 2 in tip cells. Overexpression of the basic helix-loophelix transcription factor LYL1 in transgenic mice results in shortened tails. This phenotype is associated with vessel hyperbranching and a relative paucity of straight vessels due to DLL4 downregulation in tip cells by forming aberrant complex consisting of LMO2 and LYL1. Knockdown of LMO2 or TAL1 inhibits capillary sprouting in spheroid-based angiogenesis assays, which is associated with decreased angiopoietin 2 secretion. In the same assay using mixed TAL1- and LYL1-expressing endothelial cells, TAL1 was found to be primarily located in tip cells, while LYL1-expressing cells tended to occupy the stalk position in sprouts by upregulating VEGFR1 than TAL1. Thus, the interaction between LMO2 and TAL1 in tip cells plays a key role in angiogenic switch of sprouting angiogenesis.

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Environmental oxygen regulates astrocyte proliferation to guide angiogenesis during retinal development

Development ◽

10.1242/dev.199418 ◽

2021 ◽

Vol 148 (9) ◽

Author(s):

Robin M. Perelli ◽

Matthew L. O'Sullivan ◽

Samantha Zarnick ◽

Jeremy N. Kay

Keyword(s):

Developmental Disorders ◽

Excess Oxygen ◽

Neonatal Exposure ◽

Retinal Vasculature ◽

Molecular Pathways ◽

Spatial Patterning ◽

Newborn Mice ◽

Astrocyte Proliferation ◽

Mammalian Retina ◽

Retinal Angiogenesis

ABSTRACT Angiogenesis in the developing mammalian retina requires patterning cues from astrocytes. Developmental disorders of retinal vasculature, such as retinopathy of prematurity (ROP), involve arrest or mispatterning of angiogenesis. Whether these vascular pathologies involve astrocyte dysfunction remains untested. Here, we demonstrate that the major risk factor for ROP – transient neonatal exposure to excess oxygen – disrupts formation of the angiogenic astrocyte template. Exposing newborn mice to elevated oxygen (75%) suppressed astrocyte proliferation, whereas return to room air (21% oxygen) at postnatal day 4 triggered extensive proliferation, massively increasing astrocyte numbers and disturbing their spatial patterning prior to the arrival of developing vasculature. Proliferation required astrocytic HIF2α and was also stimulated by direct hypoxia (10% oxygen), suggesting that astrocyte oxygen sensing regulates the number of astrocytes produced during development. Along with astrocyte defects, return to room air also caused vascular defects reminiscent of ROP. Strikingly, these vascular phenotypes were more severe in animals that had larger numbers of excess astrocytes. Together, our findings suggest that fluctuations in environmental oxygen dysregulate molecular pathways controlling astrocyte proliferation, thereby generating excess astrocytes that interfere with retinal angiogenesis.

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Notch1 controls macrophage recruitment and Notch signaling is activated at sites of endothelial cell anastomosis during retinal angiogenesis in mice

Blood ◽

10.1182/blood-2010-12-327015 ◽

2011 ◽

Vol 118 (12) ◽

pp. 3436-3439 ◽

Cited By ~ 84

Author(s):

Hasina H. Outtz ◽

Ian W. Tattersall ◽

Natalie M. Kofler ◽

Nicole Steinbach ◽

Jan Kitajewski

Keyword(s):

Endothelial Cell ◽

Notch Signaling ◽

Leading Edge ◽

Vascular Differentiation ◽

Vascular Integrity ◽

Sprouting Angiogenesis ◽

Macrophage Recruitment ◽

Reporter Mice ◽

Retinal Angiogenesis ◽

Tip Cells

Abstract Notch is a critical regulator of angiogenesis, vascular differentiation, and vascular integrity. We investigated whether Notch signaling affects macrophage function during retinal angiogenesis in mice. Retinal macrophage recruitment and localization in mice with myeloid-specific loss of Notch1 was altered, as these macrophages failed to localize at the leading edge of the vascular plexus and at vascular branchpoints. Furthermore, these retinas were characterized by elongated endothelial cell sprouts that failed to anastomose with neighboring sprouts. Using Notch reporter mice, we demonstrate that retinal macrophages localize between Dll4-positive tip cells and at vascular branchpoints, and that these macrophages had activated Notch signaling. Taken together, these data demonstrate that Notch signaling in macrophages is important for their localization and interaction with endothelial cells during sprouting angiogenesis.

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TIP CELLS AT THE TOP: A MULTISCALE MODEL OF SPROUTING ANGIOGENESIS

Journal of Biomechanics ◽

10.1016/s0021-9290(12)70218-x ◽

2012 ◽

Vol 45 ◽

pp. S217

Author(s):

Aurélie Carlier ◽

Liesbet Geris ◽

Hans Van Oosterwyck

Keyword(s):

Multiscale Model ◽

Sprouting Angiogenesis ◽

Tip Cells

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BMP-SMAD1/5 Signaling Regulates Retinal Vascular Development

Biomolecules ◽

10.3390/biom10030488 ◽

2020 ◽

Vol 10 (3) ◽

pp. 488 ◽

Cited By ~ 2

Author(s):

Andreas Benn ◽

Florian Alonso ◽

Jo Mangelschots ◽

Elisabeth Génot ◽

Marleen Lox ◽

...

Keyword(s):

Vascular Development ◽

Bmp Signaling ◽

Loop Formation ◽

Vessel Formation ◽

Sprouting Angiogenesis ◽

Intussusceptive Angiogenesis ◽

Morphogenetic Protein ◽

Vessel Regression ◽

Early Mouse ◽

Tip Cells

Vascular development is an orchestrated process of vessel formation from pre-existing vessels via sprouting and intussusceptive angiogenesis as well as vascular remodeling to generate the mature vasculature. Bone morphogenetic protein (BMP) signaling via intracellular SMAD1 and SMAD5 effectors regulates sprouting angiogenesis in the early mouse embryo, but its role in other processes of vascular development and in other vascular beds remains incompletely understood. Here, we investigate the function of SMAD1/5 during early postnatal retinal vascular development using inducible, endothelium-specific deletion of Smad1 and Smad5. We observe the formation of arterial-venous malformations in areas with high blood flow, and fewer and less functional tip cells at the angiogenic front. The vascular plexus region is remarkably hyperdense and this is associated with reduced vessel regression and aberrant vascular loop formation. Taken together, our results highlight important functions of SMAD1/5 during vessel formation and remodeling in the early postnatal retina.

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Schneiderian membrane adult vasculogenesis evaluated by CD31 and CD34 expression and morphological arrangement

Romanian Journal of Rhinology ◽

10.1515/rjr-2015-0026 ◽

2015 ◽

Vol 5 (20) ◽

pp. 225-228 ◽

Cited By ~ 1

Author(s):

Andreea-Ioana Derjac-Arama ◽

Codrut Sarafoleanu ◽

Mugurel Constantin Rusu ◽

Anca Vereanu

Keyword(s):

Maxillary Sinus ◽

Blood Vessels ◽

Large Diameter ◽

Schneiderian Membrane ◽

Sprouting Angiogenesis ◽

Bona Fide ◽

Tip Cells ◽

Cd34 Expression ◽

Sinus Mucosa ◽

Formation Specific

Abstract Background. Few studies approached the process of blood vessels formation in the Schneiderian membrane. We aimed at investigating by immunohistochemistry the processes that are responsible for forming new blood vessels in the human Schneiderian membrane. Material and methods. We applied CD31 and CD34 markers on bioptic samples gathered from eight adult patients negative for malignant pathologies. Filopodia-projecting endothelial tip cells (ETCs) were found and indicated processes of sprouting angiogenesis. Also, CD31-expressing monocyte-derived cells were found being involved in processes of vasculogenesis. These cells were projecting filopodia, thus being assessed as endothelial progenitor tip cells (EpTCs). Aggregates of CD31+ EpTCs were also analyzed. Further stages of lumen acquisition and large diameter vessels formation, specific for vasculogenesis, were evaluated. Results. It resulted that, specifically within the maxillary sinus mucosa, vascular remodelling is equally ensured by adult vasculogenesis and sprouting angiogenesis. Conclusion. This is, to our knowledge, the first evidence of adult vasculogenesis in the maxillary sinus mucosa, supported by bona fide bone marrow-derived CD31+ cells. The guidance mechanism of EpTCs protrusions needs further investigations for finding similarities, or dissimilarities, with the endothelial tip cells prolongations.

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