Parameswaran Sowmya, Dravid Shashank Manohar, Teotia Pooja, Krishnamoorthy Raghu R, Qiu Fang, Toris Carol, Morrison John, Ahmad Iqbal
Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA.
Department of Pharmacology, Creighton University, Omaha, Nebraska, USA.
Stem Cells. 2015 Jun;33(6):1743-58. doi: 10.1002/stem.1987.
Glaucoma, where the retinal ganglion cells (RGCs) carrying the visual signals from the retina to the visual centers in the brain are progressively lost, is the most common cause of irreversible blindness. The management approaches, whether surgical, pharmacological, or neuroprotective do not reverse the degenerative changes. The stem cell approach to replace dead RGCs is a viable option but currently faces several barriers, such as the lack of a renewable, safe, and ethical source of RGCs that are functional and could establish contacts with bona fide targets. To address these barriers, we have derived RGCs from the easily accessible adult limbal cells, reprogrammed to pluripotency by a non-nucleic acid approach, thus circumventing the risk of insertional mutagenesis. The generation of RGCs from the induced pluripotent stem (iPS) cells, also accomplished non-cell autonomously, recapitulated the developmental mechanism, ensuring the predictability and stability of the acquired phenotype, comparable to that of native RGCs at biochemical, molecular, and functional levels. More importantly, the induced RGCs expressed axonal guidance molecules and demonstrated the potential to establish contacts with specific targets. Furthermore, when transplanted in the rat model of ocular hypertension, these cells incorporated into the host RGC layer and expressed RGC-specific markers. Transplantation of these cells in immune-deficient mice did not produce tumors. Together, our results posit retinal progenitors generated from non-nucleic acid-derived iPS cells as a safe and robust source of RGCs for replacing dead RGCs in glaucoma.
青光眼是不可逆失明的最常见原因，在青光眼患者中，从视网膜向大脑视觉中枢传递视觉信号的视网膜神经节细胞（RGCs）会逐渐丧失。无论是手术、药物治疗还是神经保护治疗，目前都无法逆转这种退行性变化。利用干细胞替代死亡的RGCs是一种可行的选择，但目前面临着几个障碍，比如缺乏可再生、安全且符合伦理的功能性RGCs来源，这些RGCs还需能够与真正的靶点建立联系。为了克服这些障碍，我们从易于获取的成人角膜缘细胞中获得了RGCs，并通过非核酸方法将其重编程为多能性，从而规避了插入诱变的风险。从诱导多能干细胞（iPS细胞）中生成RGCs也是通过非细胞自主方式完成的，这一过程重现了发育机制，确保了在生化、分子和功能水平上所获得的表型与天然RGCs具有可比性，具有可预测性和稳定性。更重要的是，诱导产生的RGCs表达轴突导向分子，并显示出与特定靶点建立联系的潜力。此外，当将这些细胞移植到高眼压大鼠模型中时，它们会整合到宿主RGC层并表达RGC特异性标志物。将这些细胞移植到免疫缺陷小鼠体内不会产生肿瘤。总之，我们的研究结果表明，通过非核酸来源的iPS细胞产生的视网膜祖细胞是一种安全且强大的RGCs来源，可用于替代青光眼患者中死亡的RGCs。
