Keloid microRNA expression analysis and the influence of miR-199a-5p on the proliferation of keloid fibroblasts

The purpose of this study was to identify microRNAs (miRNAs) involved in keloid formation and determine their influence on the proliferation of keloid fibroblasts (KFs). Eight specimens each of resected keloid tissue and normal skin tissue were collected. miRNAs that are differentially expressed in keloid tissue and normal skin were detected using an miRNA microarray and verified by quantitative real-time polymerase chain reaction (RT-PCR). Seventeen differentially expressed miRNAs, including miR-199a-5p, were identified by microarray hybridization. qRT-PCR analysis confirmed the decrease in miR-199a-5p expression in keloid vs normal tissue that was detected by the microarray analysis. Mimics of differentially expressed miRNAs were then transfected into a KF cell line, and the effect of miRNA overexpression on the proliferation of KFs was assayed using the EdU assay. Compared with mock-transfected cells, KFs transfected with a miR-199a-5p mimic showed significantly lower cell proliferation and an altered cell cycle, with cells having significantly longer S and G2/M phases. The significantly lower expression of miRNA-199a-5p in keloids likely influences the cell cycle of KFs and restrains their proliferation, suggesting that miR-199a-5p probably plays a role in the regulation of KF proliferation.