Department of Biology, University of Padova, Padova, Italy.
Department of Molecular Medicine, Histology Unit, University of Padova, Padova, Italy.
Invest Ophthalmol Vis Sci. 2023 Jun 1;64(7):12. doi: 10.1167/iovs.64.7.12.
Keratoconus (KC) is an ocular disorder with a multifactorial origin. Transcriptomic analyses (RNA-seq) revealed deregulations of coding (mRNA) and non-coding RNAs (ncRNAs) in KC, suggesting that mRNA-ncRNA co-regulations can promote the onset of KC. The present study investigates the modulation of RNA editing mediated by the adenosine deaminase acting on dsRNA (ADAR) enzyme in KC.
The level of ADAR-mediated RNA editing in KC and healthy corneas were determined by two indexes in two different sequencing datasets. REDIportal was used to localize known editing sites, whereas new putative sites were de novo identified in the most extended dataset only and their possible impact was evaluated. Western Blot analysis was used to measure the level of ADAR1 in the cornea from independent samples.
KC was characterized by a statistically significant lower RNA-editing level compared to controls, resulting in a lower editing frequency, and less edited bases. The distribution of the editing sites along the human genome showed considerable differences between groups, particularly relevant in the chromosome 12 regions encoding for Keratin type II cluster. A total of 32 recoding sites were characterized, 17 representing novel sites. JUP, KRT17, KRT76, and KRT79 were edited with higher frequencies in KC than in controls, whereas BLCAP, COG3, KRT1, KRT75, and RRNAD1 were less edited. Both gene expression and protein levels of ADAR1 appeared not regulated between diseased and controls.
Our findings demonstrated an altered RNA-editing in KC possibly linked to the peculiar cellular conditions. The functional implications should be further investigated.
圆锥角膜（KC）是一种多因素起源的眼部疾病。转录组分析（RNA-seq）显示 KC 中编码（mRNA）和非编码 RNA（ncRNA）的调控失调，表明 mRNA-ncRNA 的共同调控可以促进 KC 的发生。本研究调查了腺苷脱氨酶作用于双链 RNA（ADAR）酶介导的 RNA 编辑在 KC 中的调节作用。
通过两个不同测序数据集的两个指标，确定了 KC 和健康角膜中的 ADAR 介导的 RNA 编辑水平。REDIportal 用于定位已知的编辑位点，而新的假定位点仅在最扩展的数据集中原位鉴定，并评估其可能的影响。Western Blot 分析用于测量来自独立样本的角膜中 ADAR1 的水平。
与对照组相比，KC 具有统计学上显著更低的 RNA 编辑水平，导致更低的编辑频率和更少的编辑碱基。编辑位点在人类基因组中的分布在组间存在显著差异，特别是在编码角蛋白 II 簇的染色体 12 区域。共鉴定了 32 个重编码位点，其中 17 个是新的位点。JUP、KRT17、KRT76 和 KRT79 在 KC 中的编辑频率高于对照组，而 BLCAP、COG3、KRT1、KRT75 和 RRNAD1 的编辑频率较低。ADAR1 的基因表达和蛋白水平在疾病组和对照组之间似乎没有调节。
我们的发现表明 KC 中存在异常的 RNA 编辑，这可能与特殊的细胞条件有关。其功能意义应进一步研究。
