Ectoderm dermomyotome signaling through filopodia

外胚层皮肌节通过丝状伪足信号传导

• 批准号: 6822039
• 负责人: Wilfred Foster Denetclaw
• 金额: $ 8.15万
• 依托单位: SAN FRANCISCO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-30 至 2008-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6822039
• 关键词: biological signal transduction; cell cell interaction; cell component structure /function; cell components; chick embryo; ectoderm; electron microscopy; health disparity; health science research support; intracellular transport; membrane lipids; myogenesis; nonmammalian vertebrate embryology

The development of the somitic myotome is a multistage process that is dependent on extrinsic signals (BMP4, Shh, Wnt proteins) for the regulation of somite growth, pattern formation and tissue differentiation (myotome development). Although many studies are found on the role of these signaling molecules in myogenesis, the results have not been in complete agreement and in some cases are controversial. There is at present a gap in our knowledge of somite and dermomyotome cellular activities during critical times when extrinsic signals are released into the somite environment. However, our preliminary research show that long, thin, plasma membrane structures called filopodia extend from the dermomyotome to stably interact with its overlying ectoderm. That dermomyotome-derived filopodia might mediate signaling activities between ectoderm and dermomyotome was investigated using live somite cross-sections from 2 day-old chicken embryos labeled with lipophilicfluorescent vital dyes (dil, Bodipy-FL sphingomyelin) and analyzed by confocal microscopy. Our results show for the first time that dermomyotome cells develop large numbers of filopodia that span the subectodermal space to establish stable membrane contact with ectoderm. In contrast, epithelial cells of the newly formed somites (stages I-III) do not possess fllopodia. Also, dermomyotome-derived filopodia show spatial-temporal preference for growth in the dorsomedial half of the dermomyotome to coincide with the area most active in myotome formation (epaxial myotome formation). Finally, filopodia transport, in an ectoderm-to-dermomyotome direction, large amounts of cellular membrane materials that contain lipid rafts. We propose that these transported lipid rafts with their trapped protein cargo may include extrinsic signals or their receptors and that lipid rafts facilitate the signaling activities of these extrinsic molecules previously shown to be regulators of somitic myogenesis. Thus, the regulated development of filopodia by the dermomyotome suggest a similar role to that described for cytonemes in Drosophilia embryo wing disc development. My collaboration with Dr. Holleran is providing greatly needed expertise in lipid membrane biochemistry and ultrastructural analysis to facilitate investigation of filopodia ultrastructure and growth from the dermomyotome and stable interaction with its overlying ectoderm layer. We show that the ectoderm is a 2 layer cellular structure with and outer tightly associated thin cell layer and an inner larger cell population that is separated by cavities that appear to be formed by these cells that border it. It is intriguing to speculate that signaling molecules are released into the subectoderm space for signaling function by the transient opening caused by cell-cell disassociation. My investigation with Dr. Holleran will focus on the dermomyotome-ectoderm interaction and the mechanism for the transport of cellular membrane materials through filopodia from ectoderm-to-dermomyotome.

躯体肌病组的发展是一个多阶段过程，取决于外在信号（BMP4，SHH，WNT蛋白质），用于调节体积的生长，模式形成和组织分化（肌动物的发展）。尽管发现了这些信号分子在肌发生中的作用的许多研究，但结果尚未完全一致，在某些情况下是有争议的。目前，我们在关键时期将外部信号释放到节点环境中的关键时期中的体系和皮肤瘤细胞活性存在差距。然而，我们的初步研究表明，称为丝状的长，薄的质膜结构从皮肤肌植物组延伸到与其上覆的外胚层稳定相互作用。皮肤菌衍生的丝虫病可能使用来自2个的活体横截面研究了外胚层和皮肤病组之间的信号传导活性。 用亲脂化的生命染料（DIL，Bodipy-FL鞘磷脂）标记的日间鸡胚胎，并通过共聚焦显微镜进行分析。我们的结果首次表明，皮肤瘤细胞会出现大量丝状丝虫病，这些丝状疾病跨越了皮下除外空间，以建立稳定的膜与外胚层接触。相比之下，新形成的节点（I-III阶段）的上皮细胞不具有氟霉菌症。此外，皮肤瘤衍生的丝状菌种表现出空间 - 周期性的偏好对皮肤病的背部一半的生长，以与肌肌层中最活跃的区域（层状肌球体形成）相吻合。最后，丝状运输，沿外胚层到德瘤的方向，大量含有脂质筏的细胞膜材料。我们提出，这些带有被困蛋白质货物的运输的脂质筏可能包括外在信号或其受体，而脂质筏则促进了这些外部分子的信号传导活性，以前证明是Somitic肌发生的调节剂。因此，皮肤肌动物的调节丝霉素的调节发育表明与果蝇胚胎翼盘发育中细胞质的描述的作用相似。我与Holleran博士的合作提供了脂质膜生物化学和超微结构分析方面非常需要的专业知识，以促进皮肤病组丝状超微结构和增长的研究，并与其上覆盖的外胚层相互作用。我们表明，外胚层是一个2层细胞结构，其外部和外部紧密相关的细胞层和一个内部较大的细胞种群，该细胞群体被这些与其接壤的细胞形成的空腔分离。引人注目的是，推测信号分子被通过细胞 - 细胞分离引起的瞬态打开释放到下胚层空间中，以进行信号传导功能。我对Holleran博士的调查将重点放在皮肤瘤 - 外胚层相互作用和细胞运输机制上 通过外胚层到德瘤的丝状材料通过丝状材料。