Development of Periostin Targeting Therapy for Choroidal Fibrovascular Membrane

Abstract

Purpose: We previously demonstrated that periostin (PN), specifically expressed in fibrovascular membrane (FVM), promoted both fibrosis and neovascularization in choroidal FVM formation. We developed single-stranded RNAs (NK0144) that is a novel class of RNAi targeting PN. The purpose of this study was to evaluate the effectiveness of NK0144 in choroidal FVM formation.

Methods: The optimal sequence directed against PN was determined by in vitro screening. In vivo, we generated mouse laser-induced choroidal neovascularization (CNV) model using C57BL/6J wild type mice. The distribution of NK0144 in CNV model at several time points (6hr-120hr) after intravitreous injection was evaluated using FITC-labeled NK0144. The effect of NK0144 in CNV model was assessed by comparing the volumes of CNV and fibrous tissue in NK0144 injection group to those in inverted control siRNA injection group using choroidal flat mount at 7 or 21 days after laser injury. We also evaluated the expression of PN mRNA in NK0144 injection group and inverted control siRNA injection group by real-time RT-PCR.

Results: We determined the most optimal sequence that can inhibit more than 99% of PN mRNA. In vivo, there was staining for FITC in laser spots at all the time points examined. Both the volumes of CNV at 7 days after laser injury and fibrous tissue at 21 days were significantly reduced in NK0144 injection group compared to inverted control siRNA injection group (p<0.05). Real-time RT-PCR showed that the expression of PN mRNA in NK0144 injection group was also significantly reduced compared to inverted control siRNA injection group (p<0.05).

Conclusions: These results suggest that NK0144 can be a new therapeutic modality for choroidal FVM formation.

Keywords: 453 choroid: neovascularization • 654 proliferation • 519 extracellular matrix