In vivo time-lapse imaging reveals extensive neural crest and endothelial cell interactions during neural crest migration and formation of the dorsal root and sympathetic ganglia

Abstract

During amniote embryogenesis the nervous and vascular systems interact in a process that significantly affects the respective morphogenesis of each network by forming a “neurovascular” link. The importance of neurovascular cross-talk in the central nervous system has recently come into focus with the growing awareness that these two systems interact extensively both during development, in the stem-cell niche, and in neurodegenerative conditions such as Alzheimer’s Disease and Amyotrophic Lateral Sclerosis. With respect to the peripheral nervous system, however, there have been no live, real-time investigations of the potential relationship between these two developing systems. To address this deficit, we used multispectral 4D time-lapse imaging in a transgenic quail model in which endothelial cells (ECs) express a yellow fluorescent marker, while neural crest cells (NCCs) express an electroporated red fluorescent marker. We monitored EC and NCC migration in real-time during formation of the peripheral nervous system. Our time-lapse recordings indicate that NCCs and ECs are physically juxtaposed and dynamically interact at multiple locations along their trajectories. These interactions are stereotypical and occur at precise anatomical locations along the NCC migratory pathway. NCCs migrate alongside the posterior surface of developing intersomitic vessels, but fail to cross these continuous streams of motile ECs. NCCs change their morphology and migration trajectory when they encounter gaps in the developing vasculature. Within the nascent dorsal root ganglion, proximity to ECs causes filopodial retraction which curtails forward persistence of NCC motility. Overall, our time-lapse recordings support the conclusion that primary vascular networks substantially influence the distribution and migratory behavior of NCCs and the patterned formation of dorsal root and sympathetic ganglia.

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

“…Recently, observations in trunk neural crest and endothelial cell dynamics have begun to illustrate the course of events in the trunk, but cranial neural crest cells have yet to be examined [6]. Cranial neural crest cells exit the dorsal neural tube in a rostral-to-caudal manner and migrate along dorsolateral pathways to populate the face and branchial arches [7].…”

A chemotactic model of trunk neural crest cell migration

“…Whether trunk neural crest cells readout signals from the endothelial cells that influence cell movements in the medioventral direction to within range of known ventral‐located chemotactic factors is still unclear. The present data in quail cannot rule out that trunk neural crest cells travel along a medioventral migratory pathway ‘prior’ to the presence of endothelial cells in the intersomitic furrow as current time‐lapse imaging data begins at HH16 (George et al, ), after the initial quail neural crest cells have reached the dorsal aorta. Further, without endothelial cell ablation, it is unknown whether trunk neural crest cells travel through the intersomitic furrow in the absence of endothelial cell streams.…”

“…When premigratory neural crest cells are fluorescently labeled within this transgenic quail model, the complex ballet between trunk (George et al, ) and cranial (McKinney, McLennan, & Kulesa, ) neural crest cells and endothelial cells has been visualized for the first time. In the trunk, visualization of cell behaviors in whole quail embryo explants has keenly observed that trunk neural crest cells migrate in the ventral direction along and in contact with endothelial cell streams that travel in the opposite dorsal direction within the intersomitic furrow (George et al, ). Static 3D imaging revealed that quail neural crest cells are preferentially juxtaposed to the posterior sides of the endothelial cell streams, sandwiching neural crest cells between the endothelial cell streams and rostral somite halves (George et al, ).…”

“…In the trunk, visualization of cell behaviors in whole quail embryo explants has keenly observed that trunk neural crest cells migrate in the ventral direction along and in contact with endothelial cell streams that travel in the opposite dorsal direction within the intersomitic furrow (George et al, ). Static 3D imaging revealed that quail neural crest cells are preferentially juxtaposed to the posterior sides of the endothelial cell streams, sandwiching neural crest cells between the endothelial cell streams and rostral somite halves (George et al, ). These data raise the exciting possibility that trunk neural crest and endothelial cells may use each other as a migratory scaffold (Figure c).…”

“…The exciting visual observations in transgenic quail embryos that revealed the dynamic interplay between the trunk neural crest and endothelial cells (George et al, ) suggest rationale for further experiments to examine underlying cellular and molecular signals that guide cells in opposite directions. These data add to the close relationship already observed between trunk neural crest cells, the basal lamina surrounding the medio‐ventral migratory corridor, and fibronectin/laminin molecules within the pathway (reviewed in Perris & Perissinotto et al, 2000; Thiery et al, ).…”