School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China.
State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, China.
Invest Ophthalmol Vis Sci. 2022 Apr 1;63(4):24. doi: 10.1167/iovs.63.4.24.
Abundant retinal microRNA-183 cluster (miR-183C) has been reported to be a key player in photoreceptor development and functionality in mice. However, whether there is a protagonist in this cluster remains unclear. Here, we used a mutant mouse model to study the role of miR-96, a member of miR-183C, in photoreceptor development and functionality.
The mature miR-96 sequence was removed using the CRISPR/Cas9 genome-editing system. Electroretinogram (ERG) and optical coherence tomography (OCT) investigated the changes in structure and function in mouse retinas. Immunostaining determined the localization and morphology of the retinal cells. RNA sequencing was conducted to observe retinal transcription alterations.
The miR-96 mutant mice exhibited cone developmental delay, as occurs in miR-183/96 double knockout mice. Immunostaining of cone-specific marker genes revealed cone nucleus mislocalization and exiguous Opn1mw/Opn1sw in the mutant (MT) mouse outer segments at postnatal day 10. Interestingly, this phenomenon could be relieved in the adult stages. Transcriptome analysis revealed activation of microtubule-, actin filament-, and cilia-related pathways, further supporting the findings. Based on ERG and OCT results at different ages, the MT mice displayed developmental delay not only in cones but also in rods. In addition, a group of miR-96 potential direct and indirect target genes was summarized for interpretation and further studies of miR-96-related retinal developmental defects.
Depletion of miR-96 delayed but did not arrest photoreceptor development in mice. This miRNA is indispensable for mouse photoreceptor maturation, especially for cones.
大量的视网膜 microRNA-183 簇（miR-183C）已被报道是在小鼠中感光器发育和功能的关键因素。然而，该簇中是否存在主要角色尚不清楚。在这里，我们使用突变小鼠模型来研究 miR-183C 的一个成员 miR-96 在感光器发育和功能中的作用。
使用 CRISPR/Cas9 基因组编辑系统去除成熟的 miR-96 序列。视网膜电图（ERG）和光相干断层扫描（OCT）研究了小鼠视网膜结构和功能的变化。免疫染色确定了视网膜细胞的定位和形态。进行 RNA 测序以观察视网膜转录变化。
miR-96 突变小鼠表现出与 miR-183/96 双敲除小鼠一样的锥体发育延迟。免疫染色的锥体特异性标记基因显示，在突变（MT）鼠的外节中，锥体核的定位错误和稀少的 Opn1mw/Opn1sw 在出生后第 10 天。有趣的是，这种现象在成年期可以得到缓解。转录组分析显示微管、肌动蛋白丝和纤毛相关途径的激活，进一步支持了这一发现。根据不同年龄的 ERG 和 OCT 结果，MT 小鼠不仅在锥体中，而且在杆体中都显示出发育延迟。此外，还总结了一组 miR-96 的潜在直接和间接靶基因，用于解释和进一步研究 miR-96 相关的视网膜发育缺陷。
miR-96 的缺失延迟了但没有阻止小鼠感光器的发育。这种 miRNA 对小鼠感光器的成熟是必不可少的，特别是对锥体。
