Abstract：
Aging is a major risk factor for the development or the worsening of retinal degenerative conditions. The intricate network of the neural retina determined that the retinal aging is a complicated process. The aim of this study is to delineate the transcriptomic changes of major retinal neurons during aging in C57BL/6 mice at single-cell level. We analyzed the transcriptional profiles of the photoreceptor, bipolar, amacrine, and Müller glial cells of 1.5-2 and 24-30 months old mice using single-cell RNA sequencing technique. We selectively confirmed the differences in gene expression using immunofluorescence staining and RNA in situ hybridization analysis. We found that each retinal cell type had unique changes upon aging. However, they all showed signs of dysregulated glucose and energy metabolism, and perturbed proteostasis. In particular, old Müller glia exhibited the most profound changes, including the upregulation of cell metabolism, stress-responses, antigen-presentation and immune responses and metal ion homeostasis. The dysregulated gliogenesis and differentiation was confirmed by the presence of Müller glia expressing rod-specific genes in the inner nuclear layer and the outer plexiform layer of the old retina. We further pinpointed the specific loss of GABAergic amacrine cells in old retina. Our study emphasized changes of amacrine and Müller glia during retinal aging, provided resources for further research on the molecular and cellular regulatory mechanisms underlying aging-associated retinal deterioration.
摘要：
衰老是视网膜退行性疾病发展或恶化的主要危险因素。神经视网膜的复杂网络决定了视网膜的衰老是一个复杂的过程。这项研究的目的是在单细胞水平上描述C57BL/6小鼠衰老过程中主要视网膜神经元的转录组变化。我们分析了光感受器的转录谱，双极,无碱,使用单细胞RNA测序技术对1.5-2和24-30月龄小鼠的Müller神经胶质细胞进行测序。我们使用免疫荧光染色和RNA原位杂交分析选择性地证实了基因表达的差异。我们发现每种视网膜细胞类型在老化时都有独特的变化。然而,它们都显示出葡萄糖和能量代谢失调的迹象，和扰乱的蛋白质。特别是,古老的穆勒glia表现出最深刻的变化，包括细胞代谢的上调，应激反应，抗原呈递和免疫反应以及金属离子稳态。通过在旧视网膜的内核层和外部丛状层中存在表达杆特异性基因的Müller胶质细胞，证实了胶质细胞的发生和分化失调。我们进一步查明了老年视网膜中GABA能无长突细胞的特异性丢失。我们的研究强调了视网膜衰老过程中无长碱和Müller胶质细胞的变化，为进一步研究衰老相关视网膜恶化的分子和细胞调控机制提供了资源。
