Pigmented epithelium to retinal transdifferentiation and Pax6 expression in larval Xenopus laevis
Pigmented epithelium to retinal transdifferentiation and Pax6 expression in larval Xenopus laevis
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DOI：
10.1002/jez.a.219
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发表时间：
2005-11-01
影响因子：
2.8
通讯作者：
Cannata, SM
中科院分区：
文献类型：
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作者：
Arresta, E;Bernardini, S;Cannata, SM
本研究探讨视网膜色素上皮细胞（RPE）的碎片，从非洲爪蟾幼虫解剖和植入到非晶状体切除宿主眼睛的玻璃体腔的视网膜转分化（TD）。在这些实验条件下，大多数RPE植入物转化为极化囊泡，其中邻近透镜的一侧保持RPE表型，而邻近宿主视网膜的一侧转化为层状视网膜，其中感光层面向囊泡的腔，并且神经节细胞层面向宿主视网膜。具有层状组织的新视网膜的形成是在来自宿主视网膜的诱导因子的影响下祖细胞的色素脱失、增殖和分化的结果。使用BrdU标记作为增殖阶段的标志物并使用单克隆抗体（mAbHP 1）作为视网膜形成的确定性指标，跟踪TD过程的阶段。色素性RPE细胞不表达Pax6。在RPE至视网膜TD的早期阶段，所有脱色和增殖的祖细胞均表达Pax6。Pax6表达模式的变化在分化的早期阶段变得明显，此时Pax6在新生视网膜的假定外核层（ONL）中的表达降低。最后，在晚期分化阶段，ONL，其中包含光感受器，不再表达Pax6，Pax6的表达被限制在神经节细胞层和内核层。这些结果表明，Pax6可能在RPE至视网膜TD的不同阶段具有不同的作用，作为早期视网膜决定因子，随后指导祖细胞命运。
This study examines the retinal transdifferentiation (TD) of retinal pigmented epithelium (RPE) fragments dissected from Xenopus laevis larvae and implanted into the vitreous chamber of non-lentectomized host eyes. In these experimental conditions, most RPE implants transformed into polarized vesicles in which the side adjacent to the lens maintained the RPE phenotype, while the side adjacent to the host retina transformed into a laminar retina with the photoreceptor layer facing the cavity of the vesicle and with the ganglionar cell layer facing the host retina. The formation of a new retina with a laminar organization is the result of depigmentation, proliferation and differentiation of progenitor cells under the influence of inductive factors from the host retina. The phases of the TD process were followed using BrdU labelling as a marker of the proliferation phase and using a monoclonal antibody (mAbHP1) as a definitive indicator of retina formation. Pigmented RPE cells do not express Pax6. In the early phase of RPE to retinal TD, all depigmented and proliferating progenitor cells expressed Pax6. Changes in the Pax6 expression pattern became apparent in the early phase of differentiation, when Pax6 expression decreased in the presumptive outer nuclear layer (ONL) of the new-forming retina. Finally, during the late differentiation phase, the ONL, which contains photoreceptors, no longer expressed Pax6, Pax6 expression being confined to the ganglion cell layer and the inner nuclear layer. These results indicate that Pax6 may have different roles during the different phases of RPE to retinal TD, acting as an early retinal determinant and later directing progenitor cell fate.