Transcriptional factors associated with epithelial-mesenchymal transition in choroidal neovascularization

[摘要] Purpose: To investigate thetranscriptional factors associated with epithelial-mesenchymaltransition (EMT) in choroidal neovascularization (CNV) secondary toage-related macular degeneration (AMD). Methods: Paraffin sections of CNVobtained from patients with AMD (n=12) were stained for transcriptionalfactors related to EMT, i.e., Snail, Slug, SIP1, and Twist. Asa control, postmortem sections of ocular normal tissue were used.Furthermore, using a human retinal pigment epithelial (RPE) cell line(ARPE-19), reverse transcription–polymerase chain reaction (RT–PCR) andimmunofluorescence microscopy were performed to explore the cellularlocalization and expression levels of EMT-associated transcriptionalfactors upon cytokine stimulation. Results: Of 12 specimens, 11 CNV tissues(91.6%) showed staining for Snail localized in cellular nuclei,particularly in those of RPE cells. Snail was strongly co-localizedwith α-smooth muscle antigen (SMA) in RPE cells. In contrast,postmortem human retina showed no Snail staining in RPE cells. Othertranscriptional factors, Slug, Twist and SIP1 were not detected in CNVor normal human retina. In ARPE-19 cells, RT–PCR and immunofluorescencemicroscopy showed that Snail mRNA was upregulated by transforminggrowth factor (TGF)-β and VEGF stimulation. Furthermore, TGF-β inducedrelocalization of Snail to the nucleus in RPE cells. Conclusions: The current data indicatethat Snail is a major transcriptional factor for EMT changes of RPEcells in human CNV.

[学科分类] 生物化学/生物物理