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Regulation of apoptosis in fish skin pigment cells during long-term chromatic adaptation

长期色彩适应过程中鱼皮肤色素细胞凋亡的调节

基本信息

批准号：
14599012
负责人：
SUGIMOTO Masazumi
金额：
$ 1.47万
依托单位：
Toho University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Many teleost fish can adapt their body color to a background color by changing the morphology and density of their skin pigment cells. The density of skin pigment cells in many teleost fish decreases during long term adaptation to a white background. We previously reported that apoptosis is responsible for the decrease in melanophores and that a sympathetic neurotransmitter, norepinephrine(NE), induces their apoptosis in medaka, Oryzias latipes. Because cAMP-dependent signaling pathways could be involved in promoting the survival of melanophores, NE seems to induce apoptosis by attenuating survival signals. In this study, we sought to elucidate the regulation mechanisms of pigment cell apoptosis during long-term chromatic adaptation. Addition of 10% fetal bovine serum prevented apoptotic melanophore death induced by NE in skin explant and scale skin culture. We examined effects of inhibitors of PKA, PI3-K, and MAPK. The depletion of PKA- and MAPK-dependent signals was suggested to induce apoptosis, while PI3-K inhibitors prevented apoptosis.It is known that fish larvae can adapt to a background color immediately after hatching. So we compared melanophore apoptosis in larvae with that in adult medaka during long-term adaptation to a white background. Melanophores did not decrease by apoptosis in these larvae, and NE did not induce apoptosis in cultured melanophores derived from embryo cells. These results suggested that the regulation system of apoptosis is different between larvae and adult fish.We also showed that MeRGS3L, a new RGS protein identified from medaka skin, and somatolactin, one of pituitary hormone have a possibility to be involved in the regulation of apoptosis in fish pigment cells.Using zebra fish, Danio rerio, we showed that apoptosis in superficial chromatophores contribute to the effective adaptation of dorsal skin and that prolonged adaptation also induced apoptosis in hypodermal chromatophores in the flank to alter the striped pigment patterns.

许多硬骨鱼可以通过改变它们皮肤色素细胞的形态和密度来使它们的身体颜色适应背景颜色。在长期适应白色背景的过程中，许多硬骨鱼的皮肤色素细胞密度会下降。我们以前曾报道，细胞凋亡是导致黑素细胞减少的原因，交感神经递质去甲肾上腺素(NE)诱导青冈、水稻黑素细胞的凋亡。由于cAMP依赖的信号通路可能参与促进黑素细胞的存活，NE似乎通过减弱生存信号来诱导细胞凋亡。在这项研究中，我们试图阐明长期颜色适应过程中色素细胞凋亡的调节机制。加入10%胎牛血清可防止去甲肾上腺素诱导皮肤外植体和鳞状皮肤培养中黑素细胞的凋亡。我们检测了PKA、PI3-K和MAPK抑制剂的作用。依赖于PKA和MAPK的信号被认为是诱导细胞凋亡的原因，而PI3-K抑制剂可以阻止细胞凋亡。众所周知，鱼类幼体在孵化后立即适应背景颜色。因此，在长期适应白色背景的过程中，我们比较了幼虫和成虫的黑素细胞凋亡。在这些幼虫中，黑素细胞不会因细胞凋亡而减少，去甲肾上腺素也不会诱导胚胎细胞培养的黑素细胞发生凋亡。这些结果表明，幼鱼和成鱼的细胞凋亡调控系统是不同的。此外，我们还表明，从青海鱼皮肤中发现的一种新的RGS蛋白MeRGS3L和垂体素可能参与了鱼类色素细胞的凋亡调节。以斑马鱼Danio rerio为例，我们证明了浅色细胞的凋亡有助于背部皮肤的有效适应，而长期适应也诱导了侧翼皮下着色团的细胞凋亡，从而改变了条纹色素的模式。