Adult neurogenesis in the decapod crustacean brain: a hematopoietic connection?
Adult neurogenesis in the decapod crustacean brain: a hematopoietic connection?
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DOI：
10.1111/j.1460-9568.2011.07802.x
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发表时间：
2011-09-01
影响因子：
3.4
通讯作者：
Sandeman, David C.
中科院分区：
文献类型：
--
作者：
Beltz, Barbara S.;Zhang, Yi;Sandeman, David C.
在包括甲壳类动物在内的许多生物的成年大脑中，新的神经元被产生并整合到电路中。在一些甲壳类物种中，第一代神经元前体存在于一个生态位中，表现出类似于哺乳动物神经源性生态位的特征。然而，与几代神经元前体共存的哺乳动物生态位不同，小龙虾的前体细胞谱系在空间上是分开的，从而可以确定环境和内源性调节因子对神经元前体谱系中特定世代的影响。实验还表明，克氏原虾中的第一代神经元前体不能自我更新。因此，神经源生态位外部的来源必须提供补充第一代前体细胞池的细胞，因为尽管这些细胞分裂并从生态位产生持续的第二代细胞外流，但第一代生态位前体细胞的数量不会随着生长和衰老而减少。体外研究表明，从血淋巴中提取的细胞，而不是其他组织，会被吸引并并入神经源性利基，这一现象似乎涉及5-羟色胺能机制。我们认为，在小龙虾中，造血系统可能是补充利基细胞池的细胞来源。这些和本文综述的其他研究建立了十足类甲壳类动物作为模式系统，在其中可以很容易地探索成体神经发生的潜在过程，如干细胞起源和转化。对成体神经发生的不同物种的研究将导致对基本机制的更广泛理解，以及进化过程可能如何塑造脊椎动物/哺乳动物的状况。
New neurons are produced and integrated into circuits in the adult brains of many organisms, including crustaceans. In some crustacean species, the first-generation neuronal precursors reside in a niche exhibiting characteristics analogous to mammalian neurogenic niches. However, unlike mammalian niches where several generations of neuronal precursors co-exist, the lineage of precursor cells in crayfish is spatially separated allowing the influence of environmental and endogenous regulators on specific generations in the neuronal precursor lineage to be defined. Experiments also demonstrate that the first-generation neuronal precursors in the crayfish Procambarus clarkii are not self-renewing. A source external to the neurogenic niche must therefore provide cells that replenish the first-generation precursor pool, because although these cells divide and produce a continuous efflux of second-generation cells from the niche, the population of first-generation niche precursors is not diminished with growth and aging. In vitro studies show that cells extracted from the hemolymph, but not other tissues, are attracted to and incorporated into the neurogenic niche, a phenomenon that appears to involve serotonergic mechanisms. We propose that, in crayfish, the hematopoietic system may be a source of cells that replenish the niche cell pool. These and other studies reviewed here establish decapod crustaceans as model systems in which the processes underlying adult neurogenesis, such as stem cell origins and transformation, can be readily explored. Studies in diverse species where adult neurogenesis occurs will result in a broader understanding of fundamental mechanisms and how evolutionary processes may have shaped the vertebrate/mammalian condition.