Exploring the lncRNA localization landscape within the retinal pigment epithelium under normal and stress conditions

Background Long noncoding RNAs (lncRNAs) are emerging as a class of genes whose importance has yet to be fully realized. It is becoming clear that the primary function of lncRNAs is to regulate gene expression, and they do so through a variety of mechanisms that are critically tied to their subcellular localization. Although most lncRNAs are poorly understood, mapping lncRNA subcellular localization can provide a foundation for understanding these mechanisms. Results Here, we present an initial step toward uncovering the localization landscape of lncRNAs in the human retinal pigment epithelium (RPE) using high throughput RNA-Sequencing (RNA-Seq). To do this, we differentiated human induced pluripotent stem cells (iPSCs) into RPE, isolated RNA from nuclear and cytoplasmic fractions, and performed RNA-Seq on both. Furthermore, we investigated lncRNA localization changes that occur in response to oxidative stress. We discovered that, under normal conditions, most lncRNAs are seen in both the nucleus and the cytoplasm to a similar degree, but of the transcripts that are highly enriched in one compartment, far more are nuclear than cytoplasmic. Interestingly, under oxidative stress conditions, we observed an increase in lncRNA localization in both nuclear and cytoplasmic fractions. In addition, we found that nuclear localization was partially attributable to the presence of previously described nuclear retention motifs, while adenosine to inosine (A-to-I) RNA editing appeared to play a very minimal role. Conclusions Our findings map lncRNA localization in the RPE and provide two avenues for future research: 1) how lncRNAs function in the RPE, and 2) how one environmental factor, in isolation, may potentially play a role in retinal disease pathogenesis through altered lncRNA localization.

Automated summary

This study investigates the subcellular localization of long noncoding RNAs (lncRNAs) in the human retinal pigment epithelium (RPE) using high throughput RNA-Sequencing (RNA-Seq). The results show that under normal conditions, most lncRNAs are present in both the nucleus and cytoplasm, but of those highly enriched in one compartment, more are nuclear than cytoplasmic. Under oxidative stress conditions, there is an increase in lncRNA localization in both compartments. The findings provide insights into the function of lncRNAs in the RPE and their potential role in retinal disease pathogenesis.