Department of Experimental Zoology and Neurobiology, University of Pécs, 7624 Pécs, Hungary.
János Szentágothai Research Centre, 7624 Pécs, Hungary.
Int J Mol Sci. 2021 Mar 4;22(5):2577. doi: 10.3390/ijms22052577.
It is well established that miR-9 contributes to retinal neurogenesis. However, little is known about its presence and effects in the postnatal period. To expand our knowledge, miRNA-small RNA sequencing and in situ hybridization supported by RT-qPCR measurement were carried out. Mir-9 expression showed two peaks in the first three postnatal weeks in Wistar rats. The first peak was detected at postnatal Day 3 (P3) and the second at P10, then the expression gradually decreased until P21. Furthermore, we performed in silico prediction and established that miR-9 targets OneCut2 or synaptotagmin-17. Another two microRNAs (mir-135, mir-218) were found from databases which also target these proteins. They showed a similar tendency to mir-9; their lowest expression was at P7 and afterwards, they showed increase. We revealed that miR-9 is localized mainly in the inner retina. Labeling was observed in ganglion and amacrine cells. Additionally, horizontal cells were also marked. By dual miRNA-in situ hybridization/immunocytochemistry and qPCR, we revealed alterations in their temporal and spatial expression. Our results shed light on the significance of mir-9 regulation during the first three postnatal weeks in rat retina and suggest that miRNA could act on their targets in a stage-specific manner.
miR-9 促进视网膜神经发生已得到充分证实。然而，其在出生后的存在和作用知之甚少。为了扩展我们的知识，进行了 miRNA-small RNA 测序和原位杂交，并通过 RT-qPCR 测量进行支持。miR-9 在 Wistar 大鼠出生后的前 3 周表现出两个表达高峰。第一个高峰在出生后第 3 天（P3）检测到，第二个高峰在 P10，然后表达逐渐减少，直到 P21。此外，我们进行了计算机预测，并确定 miR-9 的靶标为 OneCut2 或突触结合蛋白 17。另外两个 microRNA（mir-135、mir-218）从数据库中发现，也靶向这些蛋白质。它们表现出与 miR-9 相似的趋势；它们的表达最低在 P7 之后，然后表达增加。我们发现 miR-9 主要定位于视网膜内层。在神经节细胞和无长突细胞中观察到标记。此外，水平细胞也被标记。通过双重 miRNA 原位杂交/免疫细胞化学和 qPCR，我们揭示了它们时空表达的变化。我们的结果揭示了 miR-9 在大鼠视网膜出生后前 3 周的调控意义，并表明 miRNA 可以以特定阶段的方式作用于其靶标。
