Abstract
Purpose :
RNA molecules known as long non-coding RNAs (lncRNAs), transcripts with a length of more than 200 nucleotides, play a major role in regulating many pathophysiological processes including epithelial-mesenchymal transition (EMT). Previously, we have reported that exposure to proinflammatory cytokines (PICs, IFN-γ + TNF-α + IL-1β) induced EMT-like changes in ARPE-19 cells accompanied by differential expression of many lncRNAs including LINC00276, a lncRNA shown to be involved in the epithelial differentiation of RPE cells. In the present study, we analyzed the potential role of LINC00276 in modulating the deleterious effect of the PICs on RPE cells.
Methods :
ARPE-19 cells were cultured in DMEM containing 1% FBS and 1 mM sodium pyruvate until they exhibited epithelial morphology. The differentiated cells were exposed to PICs (IFN-γ (100 u/ml), TNF-α (10 ng/ml) and IL-1β (10 ng/ml)) in serum-free medium for 20 h or in 1% serum containing medium for 4 days. RT-PCR was used for analyzing mRNA, miRNA and lncRNA expressions. NF-κB pathway specific compounds were used to detect its involvement in regulating LINC00276 expression by the PICs.
Results :
Differentiated ARPE-19 cells responded to PICs by altering the expression of many lncRNAs: the expression of LINC01111, BANCR, and LUCAT were highly increased while those of LINC00113, LINC01085, and LINC00276 were markedly decreased. More than a 90% decrease in LINC00276 expression was observed with IFN-γ, IL-1β and TNF-α at concentrations as low as 1 unit/ml, 0.1 ng/ml and 0.1 ng/ml, respectively. Specifically, TNF-α and IL-1β were highly effective in decreasing the expression of LINC00276 while IFN-γ was ineffective. The decrease in LINC00276 expression was associated with the decrease in expression of RPE-specific genes (RPE65, MITF, TRPM1, and TRPM3), the epithelial marker CDH1 and RPE-characteristic miRNAs (miR-204 and miR-211). Regulators of the NF-κB pathway effectively modulated the PICs-induced expression of LINC00276.
Conclusions :
Loss of RPE characteristics induced by PICs were associated with altered expression of several lncRNAs including LINC00276. The expression of LINC00276 appears to be regulated by NF-κB signaling pathway. Thus, LINC00276 could potentially act as a link between RPE dysfunction and inflammatory response and, therefore, may play a role in the pathology of age-related macular degeneration (AMD).
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.