Role of CXCR4/SDF1 signaling in the initial migration of cardiac neural crest cells

Neural crest cells are migratory and multipotent cell populations that give rise to various derivatives during the development of vertebrate embryos. The cells are specified in the neural folds and undergo epithelial mesenchymal transition (EMT) to delaminate and then migrate within the embryo. Cardiac neural crest cells originate from the caudal hindbrain and migrate through the pharyngeal arches to the heart. It has been shown that CXCR4/SDF1 signaling control cardiac neural crest cells migration toward pharyngeal arches in chicken embryos. Here, we investigated the effect of disruption of CXCR4/SDF1 signaling on cardiac neural crest cell migration by implanting beads into the lumen of the closing neural tube. We first observed that a CXCR4 antagonist inhibited initial cardiac neural crest migration. We also found that an ectopic source of SDF1 caused the accumulation of cardiac neural crest cells in the dorsal neural tube and the invasion of cardiac neural crest cells into the neural tube. Furthermore, disruption of signaling led to disorganization of the neural tube basement membrane but did not affect neural crest EMT. Overall, our data indicate that CXCR4/SDF1 signaling is critical for as early as the onset of cardiac neural crest cell migration after the delamination.