Axon-bearing and axon-less horizontal cell subtypes are generated consecutively during chick retinal development from progenitors that are sensitive to follistatin.
Axon-bearing and axon-less horizontal cell subtypes are generated consecutively during chick retinal development from progenitors that are sensitive to follistatin.
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DOI：
10.1186/1471-213x-8-46
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发表时间：
2008-04-25
影响因子：
--
通讯作者：
Hallbook, Finn
中科院分区：
文献类型：
--
作者：
Edqvist, Per-Henrik D.;Lek, Madelen;Boije, Henrik;Lindback, Sarah M.;Hallbook, Finn
水平细胞是调节光感受器输出的视网膜中间神经元。关于HC在不同动物中的形态分类和功能特性的文献非常丰富，然而，对其发展背后的事件的理解仍然有限。在包括鸡在内的大多数脊椎动物中，基于轴突的存在或不存在来鉴定两种主要的水平细胞（HC）亚型。在这项工作中，我们的分子特征的HC亚型的基础上Lim 1，Isl 1，GABA和TrkA，分类是一致的，与以前定义的形态学的三个鸡HC亚型。由Lim 1和Isl 1分子定义的具有轴突和无轴突的HC亚群分别在胚胎日（E）3-4和E4-5连续出生，并表现出时间上可区分的迁移期。它们的相对数量不受细胞凋亡的调节。在E3时，激活素抑制剂卵泡抑素的高内源性水平的急剧下降与Lim 1阳性细胞的出现相一致。通过在E3注射卵泡抑素延长HC视网膜祖细胞的卵泡抑素暴露，在E9分析时增加了Lim 1和Isl 1阳性HC的数量。结果表明，轴突轴承和无轴突HC亚组的早期定义和连续产生的视网膜祖细胞群体，是敏感的卵泡抑素的抑制作用。结果与其中添加的卵泡抑素导致HC生成祖细胞增殖超过HC生成的正常时期的模型一致，从而产生迁移到HC层的两种类型的额外HC。
Horizontal cells are retinal interneurons that modulate the output from photoreceptors. A rich literature on the morphological classification and functional properties of HCs in different animals exists, however, the understanding of the events underlying their development is still limited. In most vertebrates including chicken, two main horizontal cell (HC) subtypes are identified based on the presence or absence of an axon. In this work we have molecularly characterized three HC subtypes based on Lim1, Isl1, GABA and TrkA, a classification that is consistent with three chick HC subtypes previously defined by morphology. The axon-bearing and axon-less HC subpopulations molecularly defined by Lim1 and Isl1, are born consecutively on embryonic day (E) 3–4 and E4–5, respectively, and exhibit temporally distinguishable periods of migration. Their relative numbers are not adjusted by apoptosis. A sharp decrease of high endogenous levels of the activin-inhibitor follistatin at E3 coincides with the appearance of the Lim1 positive cells. Extending the follistatin exposure of the HC retinal progenitor cells by injection of follistatin at E3 increased the number of both Lim1- and Isl1 positive HCs when analysed at E9. The results imply that the axon-bearing and axon-less HC subgroups are defined early and are generated consecutively from a retinal progenitor cell population that is sensitive to the inhibitory action of follistatin. The results are consistent with a model wherein added follistatin causes HC-generating progenitors to proliferate beyond the normal period of HC generation, thus producing extra HCs of both types that migrate to the HC layer.