Echinoderms are a phylum of marine deterostomes with a range of interesting biological features. One remarkable ability is their impressive capacity to regenerate most of their adult tissues, including the central nervous system (CNS). The research community has accumulated data that demonstrates that, in spite of the pentaradial adult body plan, echinoderms share deep similarities with their bilateral sister taxa such as hemichordates and chordates. Some of the new data reveal the complexity of the nervous system in echinoderms. In terms of the cellular architecture, one of the traits that is shared between the CNS of echinoderms and chordates is the presence of radial glia. In chordates, these cells act as the main progenitor population in CNS development. In mammals, radial glia are spent in embryogenesis and are no longer present in adults, being replaced with other neural cell types. In non-mammalian chordates, they are still detected in the mature CNS along with other types of glia. In echinoderms, radial glia also persist into the adulthood, but unlike in chordates, it is the only known glial cell type that is present in the fully developed CNS. The echinoderm radial glia is a multifunctional cell type. Radial glia forms the supporting scaffold of the neuroepithelium, exhibits secretory activity, clears up dying or damaged cells by phagocytosis, and, most importantly, acts as a major progenitor cell population. The latter function is critical for the outstanding developmental plasticity of the adult echinoderm CNS, including physiological cell turnover, indeterminate growth, and a remarkable capacity to regenerate major parts following autotomy or traumatic injury. In this review we summarize the current knowledge on the organization and function of the echinoderm radial glia, with a focus on the role of this cell type in adult neurogenesis.

中文翻译：

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棘皮动物放射状胶质细胞在成体细胞更新、无限生长和再生中的作用

棘皮动物是海洋底口动物门，具有一系列有趣的生物学特征。它们的一项非凡能力是它们能够再生大部分成体组织，包括中枢神经系统（CNS）。研究界积累的数据表明，尽管成体有五桡体的身体结构，棘皮动物与半索动物和脊索动物等双侧姊妹类群有着深刻的相似之处。一些新数据揭示了棘皮动物神经系统的复杂性。就细胞结构而言，棘皮动物和脊索动物的中枢神经系统共有的特征之一是存在放射状胶质细胞。在脊索动物中，这些细胞是中枢神经系统发育的主要祖细胞群。在哺乳动物中，放射状胶质细胞在胚胎发生过程中消耗殆尽，在成年体内不再存在，而是被其他神经细胞类型所取代。在非哺乳动物脊索动物中，它们仍然与其他类型的神经胶质细胞一起在成熟的中枢神经系统中被发现。在棘皮动物中，放射状胶质细胞也持续到成年期，但与脊索动物不同，它是完全发育的中枢神经系统中存在的唯一已知的胶质细胞类型。棘皮动物放射状胶质细胞是一种多功能细胞类型。放射状胶质细胞形成神经上皮的支撑支架，表现出分泌活性，通过吞噬作用清除死亡或受损的细胞，最重要的是，充当主要的祖细胞群。后一种功能对于成年棘皮动物中枢神经系统的杰出发育可塑性至关重要，包括生理细胞更新、不确定生长以及自切或外伤后主要部分再生的显着能力。在这篇综述中，我们总结了目前关于棘皮动物放射状胶质细胞的组织和功能的知识，重点是这种细胞类型在成体神经发生中的作用。