Circular RNA expression profile in human fibroblast premature senescence after repeated ultraviolet B irradiations revealed by microarray

Circular RNA (circRNA) is a class of noncoding RNA that regulates the activity of microRNAs and gene expression. Altered circRNA expression is associated with human diseases. The present study profiled differentially expressed circRNAs in the ultraviolet B stress-induced human fibroblast premature senescence (UVB-SIPS) model, and assessed the role of circRNA_100797 in UVB-SIPS. The UVB-SIPS model was confirmed by ss-galactosidase staining, cell viability CCK-8 assay, and flow cytometric cell cycle distribution assay, and subjected to circRNA gene chip profiling. These differentially expressed circRNAs were analyzed using the clusterProfiler R package for Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) database pathways. The selected circRNAs were confirmed using quantitative reverse transcription polymerase chain reaction (qRT-PCR),the relationship of circRNA_100797 with miR-23a-5p was assessed using luciferase reporter assay, and their functions were determined by qRT-PCR and western blot analysis. A total of 472 differentially expressed circRNAs occurred in the UVB-SIPS. qRT-PCR confirmed five of eight differentially expressed circRNAs. The GO and KEGG analyses revealed that these differently expressed circRNAs function in biology process, cell component, and molecular function. Furthermore, it was found that circRNA_100797 had a low expression in UVB-SIPS. However, when circRNA_100797 was overexpressed, the acceleration of cell proliferation and alleviation of cell cycle arrest were observed. Moreover, circRNA_100797 could target miR-23a-5p, their expression levels were inversely associated in fibroblasts, and the miR-23a-5p overexpression blocked the effect of the overexpression of circRNA_100797 in UVB-SIPS. The present study demonstrated that circRNA_100797 acts as a sponge of miR-23a-5p, and has a photoprotection role in UVB-irradiated fibroblasts.