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Serotonin regulates mouse cranial neural crest migration
1Department of Cell Biology and Anatomy, School of Medicine, University of North Carolina, Chapel Hill 27599-7090, USA.
Abstract:
Serotonergic agents (uptake inhibitors, receptor ligands) cause significant craniofacial malformations in cultured mouse embryos suggesting that 5-hydroxytryptamine (serotonin) (5-HT) may be an important regulator of craniofacial development. To determine whether serotonergic regulation of cell migration might underly some of these effects, cranial neural crest (NC) explants from embryonic day 9 (E9) (plug day = E1) mouse embryos or dissociated mandibular mesenchyme cells (derived from NC) from E12 embryos were placed in a modified Boyden chamber to measure effects of serotonergic agents on cell migration. A dose-dependent effect of 5-HT on the migration of highly motile cranial NC cells was demonstrated, such that low concentrations of 5-HT stimulated migration, whereas this effect was progressively lost as the dose of 5-HT was increased. In contrast, most concentrations of 5-HT inhibited migration of less motile, mandibular mesenchyme cells. To investigate the possible involvement of specific 5-HT receptors in the stimulation of NC migration, several 5-HT subtype-selective antagonists were used to block the effects of the most stimulatory dose of 5-HT (0.01 microM). Only NAN-190 (a 5-HT1A antagonist) inhibited the effect of 5-HT, suggesting involvement of this receptor. Further evidence was obtained by using immunohistochemistry with 5-HT receptor antibodies, which revealed expression of the 5-HT1A receptor but not other subtypes by migrating NC cells in both embryos and cranial NC explants. These results suggest that by activating appropriate receptors 5-HT may regulate migration of cranial NC cells and their mesenchymal derivatives in the mouse embryo.
Insights
Serotonin (5-hydroxytryptamine or 5-HT) influences craniofacial development by regulating neural crest cell migration. Low doses of 5-HT stimulate migration via the 5-HT1A receptor, while higher doses inhibit it.
Area of Science:
- Developmental Biology
- Neuroscience
- Cell Biology
Background:
- Serotonergic agents induce craniofacial malformations in mouse embryos.
- This suggests a crucial role for serotonin (5-hydroxytryptamine or 5-HT) in craniofacial development.
- The underlying mechanisms may involve the regulation of cell migration.
Purpose of the Study:
- To investigate if serotonergic regulation of cell migration contributes to craniofacial development.
- To determine the effects of serotonin on cranial neural crest (NC) and mandibular mesenchyme cell migration.
- To identify specific serotonin receptors involved in these migratory responses.
Main Methods:
- Modified Boyden chamber assay to measure cell migration.
- Used cranial neural crest explants and dissociated mandibular mesenchyme cells from mouse embryos.
- Administered various concentrations of serotonin and selective 5-HT receptor antagonists (e.g., NAN-190).
- Immunohistochemistry to detect 5-HT receptor expression on migrating cells.
Main Results:
- Serotonin exhibited a dose-dependent effect on cranial NC cell migration: low concentrations stimulated, while high concentrations inhibited.
- Serotonin primarily inhibited the migration of less motile mandibular mesenchyme cells.
- The 5-HT1A receptor antagonist NAN-190 blocked serotonin's stimulatory effect on NC migration.
- Immunohistochemistry confirmed the expression of the 5-HT1A receptor on migrating NC cells.
Conclusions:
- Serotonin (5-HT) plays a significant role in regulating cranial neural crest cell migration during embryonic development.
- The 5-HT1A receptor is implicated in mediating the stimulatory effects of serotonin on neural crest cell migration.
- These findings suggest a novel mechanism for serotonergic regulation of craniofacial development via cell migration.