Angiopoietin 2 signaling plays a critical role in neural crest cell migration

Abstract

BackgroundCollective neural crest cell migration is critical to the form and function of the vertebrate face and neck, distributing bone, cartilage, and nerve cells into peripheral targets that are intimately linked with head vasculature. The vasculature and neural crest structures are ultimately linked, but when and how these patterns develop in the early embryo are not well understood.ResultsUsing in vivo imaging and sophisticated cell behavior analyses, we show that quail cranial neural crest and endothelial cells share common migratory paths, sort out in a dynamic multistep process, and display multiple types of motion. To better understand the underlying molecular signals, we examined the role of angiopoietin 2 (Ang2), which we found expressed in migrating cranial neural crest cells. Overexpression of Ang2 causes neural crest cells to be more exploratory as displayed by invasion of off-target locations, the widening of migratory streams into prohibitive zones, and differences in cell motility type. The enhanced exploratory phenotype correlates with increased phosphorylated focal adhesion kinase activity in migrating neural crest cells. In contrast, loss of Ang2 function reduces neural crest cell exploration. In both gain and loss of function of Ang2, we found disruptions to the timing and interplay between cranial neural crest and endothelial cells.ConclusionsTogether, these data demonstrate a role for Ang2 in maintaining collective cranial neural crest cell migration and suggest interdependence with endothelial cell migration during vertebrate head patterning.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-016-0323-9) contains supplementary material, which is available to authorized users.

Role of Angiopoietin-2 in Vascular Physiology and Pathophysiology

“…During embryonic development, Ang2 is expressed in the developing placenta, with its expression being highest during early gestation [26], and participates in spiral artery remodeling [6]. It was also demonstrated that Ang2 is important for cranial neural crest cell migration, thus for vertebrate head patterning [27].…”

Fgf4 maintains Hes7 levels critical for normal somite segmentation clock function

“…HCR is a relatively new tool for mutant embryo analysis, just beginning to be used to analyze mutant embryos [59][60][61][62] . We used HCR to examine the expression of multiple genes in a single tissue by combining it with Imaris image analysis software.…”

Head Mesoderm Tissue Growth, Dynamics and Neural Crest Cell Migration

“…Live embryos for time lapse imaging were mounted on EC culture dorsal-side down beginning at HH9 or 10 modifying the protocol of (Chapman et al, 2001;McKinney et al, 2016) such that the EC culture was plated with only 500uL of liquid to reduce light scattering. Confocal z-stacks using 488nm laser to image Dendra2 of the transgenic quail and 633 for DiD were collected every 7 minutes for up to 12 hours with a 10x 0.45 objective.…”

“…A better understanding of the dynamics and interplay between the neural crest and tissues through which cells travel would shed light on the mechanistic basis of collective cell migration for which neural crest cells are an exemplary model (Noden, 1988;Kontges and Lumsden, 1996;Noden and Trainor, 2005;McLennan et al, 2015;McKinney et al, 2016). Detailed experiments would confirm the robustness of the stereotypic neural crest stream shape and length over the course of early head development under the constraints of a growing microenvironment.…”