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Endothelin signalling in the development of neural crest-derived melanocytes
K Opdecamp1, L Kos, H Arnheiter
1Laboratory of Developmental Neurogenetics, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Abstract:
In both mice and humans, mutations in the genes encoding the endothelin B receptor and its ligand endothelin 3 lead to deficiencies in neural crest-derived melanocytes and enteric neurons. The discrete steps at which endothelins exert their functions in melanocyte development were examined in mouse neural crest cell cultures. Such cultures, kept in the presence of fetal calf serum, gave rise to cells expressing the early melanoblast marker Dct even in the absence of the phorbol ester tetradecanoyl phorbol acetate (TPA) or endothelins. However, these early Dct+ cells did not proliferate and pigmented cells never formed unless TPA or endothelins were added. In fact, endothelin 2 was as potent as TPA in promoting the generation of both Dct+ melanoblasts and pigmented cells, and endothelin 1 or endothelin 3 stimulated the generation of melanoblasts and of pigmented cells to an even greater extent. The inhibition of this stimulation by the selective endothelin B receptor antagonist BQ-788 (N-cis-2,6-dimethylpiperidinocarbonyl-L-alpha-methylleucyl-D -1-methoxycarbonyltryptophanyl-D-norleucine) suggested that the three endothelins all signal through the endothelin B receptor. This receptor was indeed expressed in Dct+ melanoblasts, in addition to cells lacking Dct expression. The results demonstrate that endothelins are potent stimulators of melanoblast proliferation and differentiation.
Insights
Endothelins are crucial for melanocyte development, stimulating proliferation and differentiation of melanoblasts. This study reveals their potent role via the endothelin B receptor in mouse neural crest cells.
Area of Science:
- Developmental biology
- Cell signaling
- Pigmentation genetics
Background:
- Mutations in endothelin B receptor and endothelin 3 genes cause deficiencies in neural crest-derived melanocytes and enteric neurons in mice and humans.
- Endothelins play a role in the development of neural crest-derived cells, including melanocytes.
Purpose of the Study:
- To investigate the specific roles of endothelins in melanocyte development using mouse neural crest cell cultures.
- To determine the signaling pathways and receptor involvement in endothelin-mediated melanocyte differentiation.
Main Methods:
- Culturing mouse neural crest cells in the presence of fetal calf serum.
- Assessing the expression of the melanoblast marker Dct.
- Treating cultures with tetradecanoyl phorbol acetate (TPA) or various endothelins (endothelin 1, 2, and 3).
- Utilizing the endothelin B receptor antagonist BQ-788 to block receptor activity.
Main Results:
- Early melanoblasts (Dct+) formed without TPA or endothelins but did not proliferate or pigment.
- TPA and endothelins (1, 2, and 3) were required for melanoblast proliferation and the formation of pigmented cells.
- Endothelin 2 was as potent as TPA, while endothelin 1 and 3 were even more potent in promoting melanogenesis.
- BQ-788 inhibited endothelin-stimulated melanogenesis, confirming signaling through the endothelin B receptor.
- The endothelin B receptor was expressed on both Dct+ melanoblasts and Dct- cells.
Conclusions:
- Endothelins are potent stimulators of melanoblast proliferation and differentiation.
- Signaling through the endothelin B receptor is essential for endothelin-mediated melanocyte development.
- These findings highlight the critical role of the endothelin system in pigmentation and neural crest cell development.