Protein Kinase A inhibitor H89 attenuated experimental proliferative vitreoretinopathy

Abstract

Purpose : Proliferative vitreoretinopathy (PVR) is the major cause of failure in surgery for rhegmatogenous retinal detachment . Epithelial-to-mesenchymal transition (EMT) of reitnal pigment epithelium(RPE) mediates the main pathogenesis of PVR. Currently there is no effective treatment available,so this study aimed to explore the role of Protein Kinase A(PKA) inhibitor H89 in experimental PVR and thus develop a novel therapeutic approach for PVR.

Methods : In vivo PVR model was made by intravitreal injection of ARPE19 and Platelet rich plasma (PRP) in SD rats. The rats were divided into 3 groups: PBS , ARPE19 +PRP and ARPE19+PRP+H89 respectively. Electroretinogram (ERG) was recorded at indicated times, EMT related markers were evaluated by immunofluorescence (IF) for dissected eyes. In vitro PVR model was prepared by TGFβ treatment. Q-PCR,Western Blot and IF were performed . Scratch assay, cell migration by trans well assay and PKA kinase activity were also examined.

Results : In vivo PVR model, the intervention of H-89 prevented the decrease of b-wave amplitude of ERG in PVR group. H89 attenuated the formation of epiretinal membrane and downregulated the expression of a-SMA and FN1. In vitro, H89 treatment inhibited EMT related genes expression at both protein and mRNA level in RPE cells. In addition, TGFβ1-induced cell migration and proliferation were blocked by H89 treatment, as shown in scratch assay and transwell experiments. It was also found that TGFβ1 treatment increased PKA activity in dose- and time dependent manner.

Conclusions : This study demonstrated that activation of PKA pathway was involved in PVR, H89 can effectively inhibit the EMT of RPE cells in vivo and in vitro model. These data will provide a novel insight into the pathogenesis of PVR. H89 intervention merits further clinical investigation.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

Figure 1.H89 inhibited PVR in vivo. A: Treatment of H-89 can rescue the decrease of the b-wave amplitude(There were 6 eyes for each group). B: Treatment of H89 attenuated the formation of epiretinal membrane and downregulated the expression of a-SMA and FN1.

 

Figure 2.H89 inhibited PVR in vitro.A-D: H89 treatment inhibited EMT related genes expression at both mRNA and protein level (q-PCR,WB and IF). E-H: H89 treatment bloked TGFβ1 induced cell migration and proliferation (scratch and trans well experiments.) I-L:TGFβ1 increased PKA activity in dose- and time dependent manner.