Bhatia Bhairavi, Singhal Shweta, Lawrence Jean M, Khaw Peng T, Limb G Astrid
University College London (UCL) Institute of Ophthalmology and Moorfields Eye Hospital, London EC1V 9EL, UK.
Exp Eye Res. 2009 Sep;89(3):373-82. doi: 10.1016/j.exer.2009.04.005. Epub 2009 Apr 18.
Much interest has been generated by the identification of neural stem cells in the human neural retina and ciliary body. However, it is not clear whether stem cells identified in these ocular compartments are of the same origin or whether they ontogenically derive from different cell populations. This study examined the in situ anatomical distribution of these cells within the neural retina and ciliary body, as well as their ability to proliferate in response to EGF. Human retinae and ciliary body were examined for co-expression of Nestin, cellular retinaldehyde binding (CRALBP) or Vimentin, and the stem cell markers SOX2, CHX10, NOTCH1 and SHH. Retinal explants were cultured with epidermal growth factor (EGF) to assess retinal cell proliferation. Intense Nestin and CRALBP staining was observed in the neural retinal margin, where cells formed bundles of spindle cells (resembling glial cells) that lacked lamination and co-stained for SOX2, CHX10 and SHH. This staining differentiated the neural retina from the ciliary epithelium, which expressed SOX2, CHX10 and NOTCH1 but not Nestin or CRALBP. Nestin and CRALBP expression decreased towards the posterior retina, where it anatomically identified a population of Müller glia. All Vimentin positive Müller glia co-stained for SOX2, but only few Vimentin positive cells expressed Nestin and SOX2. Cells of the retinal margin and the inner nuclear layer (INL), where the soma of Müller glia predominate, re-entered the cell cycle upon retinal explant culture with EGF. Lack of lamination and abundance of Müller glia expressing stem cell markers in the marginal region of the adult human retina resemble the ciliary marginal zone (CMZ) of fish and amphibians. The findings that cells in this CM-like zone, as well in the inner nuclear layer proliferate in response to EGF suggest that the adult human retina has regenerative potential. Identification of factors that may promote retinal regeneration in the adult human eye would provide efficient treatments for retinal degenerative conditions for which treatments are not yet available.
人类神经视网膜和睫状体中神经干细胞的鉴定引发了广泛关注。然而，目前尚不清楚在这些眼内区域鉴定出的干细胞是否起源相同，或者它们在个体发育上是否源自不同的细胞群体。本研究检测了这些细胞在神经视网膜和睫状体中的原位解剖分布，以及它们对表皮生长因子（EGF）的增殖反应能力。对人类视网膜和睫状体进行检测，以观察巢蛋白（Nestin）、细胞视黄醛结合蛋白（CRALBP）或波形蛋白（Vimentin）与干细胞标志物SOX2、CHX10、NOTCH1和音猬因子（SHH）的共表达情况。将视网膜外植体与表皮生长因子（EGF）一起培养，以评估视网膜细胞的增殖情况。在神经视网膜边缘观察到强烈的巢蛋白和CRALBP染色，此处细胞形成纺锤体细胞束（类似于神经胶质细胞），缺乏分层结构，且同时表达SOX2、CHX10和SHH。这种染色将神经视网膜与睫状体上皮区分开来，睫状体上皮表达SOX2、CHX10和NOTCH1，但不表达巢蛋白或CRALBP。巢蛋白和CRALBP的表达朝着视网膜后部降低，在此处从解剖学上可识别出一群米勒胶质细胞。所有波形蛋白阳性的米勒胶质细胞均同时表达SOX2，但只有少数波形蛋白阳性细胞表达巢蛋白和SOX2。视网膜边缘和内核层（INL）的细胞（此处以米勒胶质细胞的胞体为主）在与EGF一起进行视网膜外植体培养时重新进入细胞周期。在成人视网膜边缘区域缺乏分层结构以及大量表达干细胞标志物的米勒胶质细胞类似于鱼类和两栖动物的睫状边缘区（CMZ）。在这个类似CMZ的区域以及内核层中的细胞对EGF有增殖反应，这一发现表明成人人类视网膜具有再生潜力。鉴定可能促进成人眼视网膜再生的因素将为目前尚无有效治疗方法的视网膜退行性疾病提供有效的治疗手段。
