Increased ocular levels of microRNA-148a in cases of retinal detachment promote epithelial-mesenchymal transition

PURPOSE. The purpose of this study was to determine microRNA expression in vitreous and subretinal fluid (SRF) samples from patients with retinal detachment (RD). The pathological importance of the identified microRNA transcript levels was analyzed in vitro. METHODS. Vitreous fluid was collected from 10 patients with macular hole (MH), vitreomacular traction syndrome (VMTS), or foveoschisis and from 11 patients with RD. Subretinal fluid was collected from 7 patients with RD. Of these, blood serum was collected in 4 patients. MicroRNA microarray profiling was performed to identify microRNA transcripts that were present in vitreous fluid, and more redundantly detected in SRF, of patients with RD, but not detected in control eyes. Western blotting and scratch assays were performed in ARPE-19 cells and primary human RPE cell lines transfected with microRNA to elucidate the effect of identified microRNA transcripts on epithelial-mesenchymal transition (EMT). RESULTS. MicroRNA microarray profiling revealed that hsa-miR-148a-3p was the most redundantly detected transcript in SRF and vitreous fluid from patients with RD, but not those with the other diseases. Expression levels of hsa-miR-148a-3p were higher in SRF samples than in blood serum samples in 3 out of 4 patients. Following hsa-miR-148a-3p mimic transfection, ARPE-19 and human RPE cells demonstrated increased expression of α-smooth muscle actin by Western blotting and increased migration ability during scratch assays. CONCLUSIONS. The results of the present study indicate that hsa-miR-148a-3p was specifically detected in RD and promotes EMT in RPE.