Developing rods transplanted into the degenerating retina of Crx-knockout mice exhibit neural activity similar to native photoreceptors.
Developing rods transplanted into the degenerating retina of Crx-knockout mice exhibit neural activity similar to native photoreceptors.
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DOI：
10.1002/stem.1372
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发表时间：
2013-06
期刊：
影响因子：
--
通讯作者：
Takahashi M
中科院分区：
文献类型：
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作者：
Homma K;Okamoto S;Mandai M;Gotoh N;Rajasimha HK;Chang YS;Chen S;Li W;Cogliati T;Swaroop A;Takahashi M
功能障碍或死亡的光感受器的替代为视网膜神经退行性疾病提供了一种有希望的方法，包括年龄相关性黄斑变性和视网膜色素变性。几项研究已经证明了当移植到野生型或退化的视网膜中时，发育中的视杆细胞的整合和分化;然而，供体细胞的生理学和功能尚未充分定义。在这里，我们描述的生理特性的开发杆光感受器，标记与GFP驱动的启动子杆分化因子，Nrl。GFP标记的发育中的视杆显示出比在完全发育的光感受器中观察到的更小的Ca 2+响应和整流外向电流，这表明它们的不成熟发育状态。这些未成熟的杆也表现出超极化激活的环核苷酸门控（HCN）通道的激活诱导的超极化激活电流（Ih）。当移植到野生型或视网膜变性小鼠的视网膜下腔时，GFP标记的发育中的视杆细胞可以整合到野生型小鼠视网膜中的光感受器外核层中，并且表现出与天然视杆细胞光感受器相当的Ca 2+响应和膜电流。移植到Crx基因敲除小鼠视网膜后两周内，一部分移植的视杆细胞形成视紫红质阳性的外段样结构，并在膜去极化和超极化时产生整流外向电流和Ih。来自诱导的多能干细胞（iPS）的GFP阳性视杆也显示出与天然发育视杆光感受器相似的膜电流Ih，表达视杆特异性光转导基因和HCN-1通道。我们的结论是，Nr 1启动子驱动的GFP标记的供体光感受器表现出杆的生理特性，iPS细胞衍生的杆在体外可能提供一个可再生的来源，用于细胞替代疗法。
Replacement of dysfunctional or dying photoreceptors offers a promising approach for retinal neurodegenerative diseases, including age-related macular degeneration and retinitis pigmentosa. Several studies have demonstrated the integration and differentiation of developing rod photoreceptors when transplanted in wild type or degenerating retina; however, the physiology and function of the donor cells are not adequately defined. Here, we describe the physiological properties of developing rod photoreceptors that are tagged with GFP driven by the promoter of rod differentiation factor, Nrl. GFP-tagged developing rods show Ca2+ responses and rectifier outward currents that are smaller than those observed in fully developed photoreceptors, suggesting their immature developmental state. These immature rods also exhibit hyperpolarization-activated current (Ih) induced by the activation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. When transplanted into the subretinal space of wild type or retinal degeneration mice, GFP-tagged developing rods can integrate into the photoreceptor outer nuclear layer in wild-type mouse retina, and exhibit Ca2+ responses and membrane current comparable to native rod photoreceptors. A proportion of grafted rods develop rhodopsin-positive outer segment-like structures within two weeks after transplantation into the retina of Crx-knockout mice, and produce rectifier outward current and Ih upon membrane depolarization and hyperpolarization. GFP-positive rods derived from induced pluripotent stem (iPS) cells also display similar membrane current Ih as native developing rod photoreceptors, express rod-specific phototransduction genes, and HCN-1 channels. We conclude that Nrl-promoter driven GFP-tagged donor photoreceptors exhibit physiological characteristics of rods and that iPS cell-derived rods in vitro may provide a renewable source for cell replacement therapy.