Increased Ocular Levels of MicroRNA-148a in Cases of Retinal Detachment Promote Epithelial–Mesenchymal Transition

Abstract

Citation: Takayama K, Kaneko H, Hwang S-J, et al. Increased ocular levels of microRNA-148a in cases of retinal detachment promote epithelialmesenchymal transition. Invest Ophthalmol Vis Sci. 2016;57:269957: -270557: . DOI:10.1167 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 a-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.

Cytokine profiling in the sub-silicone oil fluid after vitrectomy surgeries for refractory retinal diseases

“…Lambrou et al . performed an animal experiment to examine the effect of SO or SOF on retinal pigment epithelial (RPE) cells that are thought to be one of the major players in inducing PVR by biologically promoting epithelial-mesenchymal transition 18, 19 . They suggested that vitreous cavity SO had an increased mitogenic activity for RPE cells compared to gas-filled or fluid-filled-vitreous 19 .…”

“…All vitreous samples were collected by dry vitrectomy at the beginning of vitrectomy surgery using a vitrectomy cutter before infusion initiation 18 . All samples were immediately stored at −80 °C until use.…”

Biological Involvement of MicroRNAs in Proliferative Vitreoretinopathy

“…Table 2 lists the previous publications of studies that have analyzed microRNAs from surgically collected human vitreous. 44–49 In most studies, microRNAs were detected by microRNA arrays, followed by reconfirmation by quantitative real-time polymerase chain reaction assay. Almost all of the current surgical instruments used in vitrectomy surgery are disposable and RNase-free, and collecting the vitreous from patients without any additional risks is possible during the regular surgical procedure.…”

“…50–52 Recently, aberrant expression of microRNAs in RPE cells undergoing EMT was reported. 47,49,53–59 RPE cells undergo EMT and contribute to the pathogenesis of PVR. We focused on previous studies that have examined the effect of microRNAs on human RPE cells via EMT.…”

“…61 Recently, we found that miR-148a was expressed specifically in the vitreous from eyes with RD and that miR-148a expression correlated with the size of the retinal breaks and duration of RD, which has been reported to be the possible cause of PVR. 47,63 Based on the aforementioned reports showing that the vitreous has multiple upregulated inflammatory cytokines, we examined correlations between miR-148 expression and inflammatory cytokines from eyes with RD. Demographic and clinical characteristics, and the results of inflammatory cytokine levels of the 20 patients with RD are listed in Table 4.…”