Adult neurogenesis in crayfish: Origin, expansion, and migration of neural progenitor lineages in a pseudostratified neuroepithelium
Adult neurogenesis in crayfish: Origin, expansion, and migration of neural progenitor lineages in a pseudostratified neuroepithelium
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DOI：
10.1002/cne.24820
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发表时间：
2019-12-17
影响因子：
2.5
通讯作者：
Beltz, Barbara S.
中科院分区：
文献类型：
--
作者：
Brenneis, Georg;Beltz, Barbara S.
在十足类甲壳动物脑中发现成体神经元20年后，产生这些神经谱系的中脑增殖系统（DPS）已成为无脊椎动物成体神经发生的模型。对小龙虾的研究为DPS的解剖学、细胞动力学和调控提供了大量的见解。与传统思维相反，最近的证据表明，小龙虾DPS中的神经原性生态位缺乏自我更新的干细胞，其细胞库通过先天免疫系统产生的血细胞的整合来维持。本文详细研究了成年期神经前体细胞的起源、分裂和迁移方式。我们发现，小生境细胞池不仅补充血细胞的整合，但也由有限数量的对称细胞分裂的一些特点，让人联想到interkinetic核迁移。一旦在小生境中被指定，第一代NPs就充当过渡扩增中间NPs，当它们沿着沿着迁移流向靶脑区域移动时，这些中间NPs最终退出并产生多细胞克隆。不同的克隆可以同时迁移的流，但占据单独的轨道，并显示时空灵活的分裂模式。在此基础上，我们提出了一个扩展的DPS模型，强调在其他节肢动物和脊椎动物的假复层神经上皮的结构相似性。该模型包括血细胞整合和内在细胞增殖，以协同抵消动物寿命期间的小生境细胞池消耗。此外，我们讨论的相似之处，最近的研究结果对哺乳动物的成年神经发生，这两个系统似乎表现出类似的解耦增殖补给司和消费神经原性司。
Two decades after the discovery of adult-born neurons in the brains of decapod crustaceans, the deutocerebral proliferative system (DPS) producing these neural lineages has become a model of adult neurogenesis in invertebrates. Studies on crayfish have provided substantial insights into the anatomy, cellular dynamics, and regulation of the DPS. Contrary to traditional thinking, recent evidence suggests that the neurogenic niche in the crayfish DPS lacks self-renewing stem cells, its cell pool being instead sustained via integration of hemocytes generated by the innate immune system. Here, we investigated the origin, division and migration patterns of the adult-born neural progenitor (NP) lineages in detail. We show that the niche cell pool is not only replenished by hemocyte integration but also by limited numbers of symmetric cell divisions with some characteristics reminiscent of interkinetic nuclear migration. Once specified in the niche, first generation NPs act as transit-amplifying intermediate NPs that eventually exit and produce multicellular clones as they move along migratory streams toward target brain areas. Different clones may migrate simultaneously in the streams but occupy separate tracks and show spatio-temporally flexible division patterns. Based on this, we propose an extended DPS model that emphasizes structural similarities to pseudostratified neuroepithelia in other arthropods and vertebrates. This model includes hemocyte integration and intrinsic cell proliferation to synergistically counteract niche cell pool depletion during the animal's lifespan. Further, we discuss parallels to recent findings on mammalian adult neurogenesis, as both systems seem to exhibit a similar decoupling of proliferative replenishment divisions and consuming neurogenic divisions.