Voltage‐dependent ‐L‐type Ca²⁺ channels participate in regulating neural crest migration and differentiation

Abstract

General models of cell activation implicate Ca2+ conductance as pivotal in conveying transmembrane signals. During embryonic development, both cell migration and differentiation are influenced by changes in Ca2+; and, as a consequence, the modulation of Ca2+ is important in the control of many morphogenetic processes. Because Ca2+ conductance may be regulated at voltage-dependent Ca2+ channels (VD-CCs), we investigated whether neural crest cells develop VDCCs and, if so, whether they function in regulating migration and establishing cytomorphology. Autoradiography indicates that neural crest cells in vitro develop -L-type Ca2+ channels during migration and differentiation. Blockage of these channels by verapamil, both in vivo and in vitro, leads to a dramatic and reversible inhibition of neural crest migration. Alterations are manifest in vitro in cell-to-cell and cell-to-substratum contact and in the organization of the actin cytoskeleton. In whole embryos, verapamil or nifedipine inhibits pigment pattern formation. Moreover, blockage of the -L-type Ca2+ channels in whole embryos or cultures, after cells have already migrated and differentiated, results in a significant change in individual cell shape and in the overall pigment cell pattern, suggesting further that maintenance of the differentiated state also requires regulation at the -L-type Ca2+ channel. Since certain aspects of neural crest adhesion and cytoskeletal function are dependent on Ca2+, it is suggested that interactions that regulate the availability of Ca2+ through the VDCC may provide coordinate control of motile and adhesive interactions at the cell-substratum interface.

Embryonic and larval expression of zebrafish voltage‐gated sodium channel α‐subunit genes

“…Overall, the results indicate that scna gene expression occurs sufficiently early during zebrafish embryogenesis for sodium channels to play developmental roles, similar to calcium channels (Moran, 1991;Komuro and Rakic, 1992;Moreau et al, 1994;Drean et al, 1995;Leclerc et al, 1995Leclerc et al, , 1997Leclerc et al, , 2000Palma et al, 2001;Rottbauer et al 2001;Wallingford et al, 2001). The experimental strengths of the zebrafish model allow systematic analysis of the embryonic roles of each scna gene as well as specific splice variants.…”

“…Voltage-gated calcium channels play roles in a diverse range of early developmental processes, including mesodermal patterning and neural induction (Moreau et al, 1994;Drean et al, 1995;Leclerc et al, 1995Leclerc et al, , 1997Leclerc et al, , 2000Palma et al, 2001;Wallingford et al, 2001). At later stages, voltage-gated calcium channels also regulate differentiation of cardiac tissue and neuronal migration (Moran, 1991;Komuro and Rakic, 1992;Rottbauer et al, 2001).…”

Homocysteine enhances cardiac neural crest cell attachment in vitro by increasing intracellular calcium levels

“…For instance, Ca 2ϩ channel antagonists stimulate precocious NC cell migration from neural tube explants in vitro (Newgreen and Gooday, 1985). Ca 2ϩ transients also play a role in mediating NC differentiation in vitro (Moran, 1991;Matsumoto, 1999, 2000). Of interest, ethanol, a well-characterized teratogen causing neural tube and NC-related defects, increases intracellular levels of Ca 2ϩ leading to increased apoptosis in NC precursors and this effect can be prevented by BAPTA-AM (Debelak- Kragtorp et al, 2003).…”

Calcium influx through L-type CaV1.2 Ca2+ channels regulates mandibular development

“…At this voltage, steadystate inactivation curves for Ca V 1.2 WT and Ca V 1.2 TS channels begin to diverge, so the fraction of Ca V 1.2 TS channels inactivated would be significantly smaller than that of Ca V 1.2 WT channels (1). Thus, after Ca V 1.2 channels open to participate in the Ca 2+ waves that accompany neural crest migration (17,21), additional Ca 2+ likely continues to flow through Ca V 1.2 TS channels for some time, even after a return to more negative resting membrane potentials.…”

“…The identification of Ca V 1.2 expression in cranial neural crest-derived cells (Figure 1, E and F) and the developmental effects observed after perturbing Ca V 1.2 ( Figures 2-4), prompted us to test whether cranial neural crest cells express functional Ca V 1.2 channels. Previously, voltage-gated L-type Ca 2+ channels have been hypothesized to regulate neural crest migration and differentiation (17), yet the contributions of specific L-type Ca 2+ channels have not been identified, and analysis by electrophysiologic methods has not yet been performed. We did not find that Ca V 1.2 regulated cranial neural crest cell migration.…”