In Vivo Analysis of Optic Fissure Fusion in Zebrafish: Pioneer Cells, Basal Lamina, Hyaloid Vessels, and How Fissure Fusion is Affected by BMP
In Vivo Analysis of Optic Fissure Fusion in Zebrafish: Pioneer Cells, Basal Lamina, Hyaloid Vessels, and How Fissure Fusion is Affected by BMP
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DOI：
10.3390/ijms21082760
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发表时间：
2020-04-01
影响因子：
5.6
通讯作者：
Heermann, Stephan
中科院分区：
文献类型：
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作者：
Eckert, Priska;Knickmeyer, Max D.;Heermann, Stephan
缺损，持续性视神经裂，经常导致先天性失明。在这里，我们专注于使用在斑马鱼体内延时成像的视裂融合。我们鉴定了融合起始细胞，我们称之为“先锋细胞”。“基于神经视网膜（NR）前体标志物rx2的形态，定位和下调，这些细胞可以被认为是视网膜色素上皮（RPE）祖细胞。值得注意的是，先锋细胞在融合后重新获得rx2表达并整合到NR中，表明它们不属于RPE祖细胞库，这得到了先锋细胞中RPE标志物表达缺乏的支持。它们在近侧裂区的边缘之间建立了第一个细胞接触，并分离了玻璃体动脉和静脉。开始后，融合部位向远端发展，增加玻璃体动脉和静脉之间的距离。定时BMP（骨形态发生蛋白）诱导，导致缺损，并没有改变裂隙边缘的形态，但它确实影响了边缘内NR和RPE标记物的表达。此外，它导致裂内存在持续的基底板和持续的眼周间充质和玻璃体血管残余，支持裂缘内BMP拮抗作用的必要性。裂隙融合受阻对眼血管系统有严重影响。
Colobomata, persistent optic fissures, frequently cause congenital blindness. Here, we focused on optic fissure fusion using in vivo time-lapse imaging in zebrafish. We identified the fusion initiating cells, which we termed "pioneer cells." Based on morphology, localization, and downregulation of the neuroretinal (NR) precursor marker rx2, these cells could be considered as retinal pigment epithelial (RPE) progenitors. Notably, pioneer cells regain rx2 expression and integrate into the NR after fusion, indicating that they do not belong to the pool of RPE progenitors, supported by the lack of RPE marker expression in pioneer cells. They establish the first cellular contact between the margins in the proximal fissure region and separate the hyaloid artery and vein. After initiation, the fusion site is progressing distally, increasing the distance between the hyaloid artery and vein. A timed BMP (Bone Morphogenetic Protein) induction, resulting in coloboma, did not alter the morphology of the fissure margins, but it did affect the expression of NR and RPE markers within the margins. In addition, it resulted in a persisting basal lamina and persisting remnants of periocular mesenchyme and hyaloid vasculature within the fissure, supporting the necessity of BMP antagonism within the fissure margins. The hampered fissure fusion had severe effects on the vasculature of the eye.