The John Curtin School of Medical Research, The Australian National University, Garran Road, Acton, Australian Capital Territory, 2601, Australia.
The Australian National University Medical School, Mills Road, Australian Capital Territory, Acton, 2601, Australia.
Mol Neurobiol. 2021 Feb;58(2):835-854. doi: 10.1007/s12035-020-02158-z. Epub 2020 Oct 9.
Although extensively investigated in inflammatory conditions, the role of pro-inflammatory microRNAs (miRNAs), miR-155 and miR-146a, has not been well-studied in retinal degenerative diseases. We therefore aimed to explore the role and regulation of these miRNA in the degenerating retina, with a focus on miR-155. C57BL/6J mice were subjected to photo-oxidative damage for up to 5 days to induce focal retinal degeneration. MiR-155 expression was quantified by qRT-PCR in whole retina, serum, and small-medium extracellular vesicles (s-mEVs), and a PrimeFlow™ assay was used to identify localisation of miR-155 in retinal cells. Constitutive miR-155 knockout (KO) mice and miR-155 and miR-146a inhibitors were utilised to determine the role of these miRNA in the degenerating retina. Electroretinography was employed as a measure of retinal function, while histological quantification of TUNEL and IBA1 positive cells was used to quantify photoreceptor cell death and infiltrating immune cells, respectively. Upregulation of miR-155 was detected in retinal tissue, serum and s-mEVs in response to photo-oxidative damage, localising to the nucleus of a subset of retinal ganglion cells and glial cells and in the cytoplasm of photoreceptors. Inhibition of miR-155 showed increased function from negative controls and a less pathological pattern of IBA1 cell localisation and morphology at 5 days photo-oxidative damage. While neither dim-reared nor damaged miR-155 KO animals showed retinal histological difference from controls, following photo-oxidative damage, miR-155 KO mice showed increased a-wave relative to controls. We therefore consider miR-155 to be associated with the inflammatory response of the retina in response to photoreceptor-specific degeneration.
虽然在炎症条件下广泛研究了促炎 microRNA（miRNA），miR-155 和 miR-146a，但它们在视网膜退行性疾病中的作用尚未得到很好的研究。因此，我们旨在探索这些 miRNA 在退化视网膜中的作用和调节，重点研究 miR-155。C57BL/6J 小鼠接受光氧化损伤，最长达 5 天，以诱导局灶性视网膜变性。通过 qRT-PCR 在整个视网膜、血清和中小细胞外囊泡（s-mEVs）中定量测定 miR-155 的表达，并使用 PrimeFlow™ 测定法鉴定 miR-155 在视网膜细胞中的定位。利用组成型 miR-155 敲除（KO）小鼠和 miR-155 和 miR-146a 抑制剂来确定这些 miRNA 在退化视网膜中的作用。视网膜电图用于评估视网膜功能，而 TUNEL 和 IBA1 阳性细胞的组织学定量用于分别量化光感受器细胞死亡和浸润的免疫细胞。光氧化损伤后，在视网膜组织、血清和 s-mEVs 中检测到 miR-155 的上调，定位于一小部分视网膜神经节细胞和神经胶质细胞的核内，以及光感受器的细胞质中。miR-155 的抑制显示出比负对照更高的功能，并且在 5 天光氧化损伤时 IBA1 细胞定位和形态的病理性模式更少。虽然暗养或未受损的 miR-155 KO 动物的视网膜组织学与对照没有差异，但在光氧化损伤后，miR-155 KO 小鼠的 a 波相对对照增加。因此，我们认为 miR-155 与光感受器特异性变性引起的视网膜炎症反应有关。
