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Protein Kinase A Inhibitor H89 Attenuates Experimental Proliferative Vitreoretinopathy
Yali Lyu1,1, Wei Xu1, Jieping Zhang1,1
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Purpose:
This study aimed to explore the role of the protein kinase A (PKA) pathway in proliferative vitreoretinopathy (PVR) and the effect of the PKA inhibitor H89 on experimental PVR.
Methods:
Epiretinal membranes (ERMs) were acquired from PVR patients and analyzed by frozen-section immunofluorescence. An in vivo model was developed by intravitreal injecting rat eyes with ARPE-19 cells and platelet-rich plasma, and changes in eye structures and vision function were observed. An in vitro epithelial-mesenchymal transition (EMT) cell model was established by stimulating ARPE-19 cells with transforming growth factor (TGF)-β. Alterations in EMT-related genes and cell function were detected. Mechanistically, PKA activation and activity were explored to assess the relationship between TGF-β1 stimulation and the PKA pathway. The effect of H89 on the TGF-β-Smad2/3 pathway was detected. RNA sequencing was used to analyze gene expression profile changes after H89 treatment.
Results:
PKA was activated in human PVR membranes. In vivo, H89 treatment protected against structural changes in the retina and prevented decreases in electroretinogram b-wave amplitudes. In vitro, H89 treatment inhibited EMT-related gene alterations and partially reversed the functions of the cells. TGF-β-induced PKA activation was blocked by H89 pretreatment. H89 did not affect the phosphorylation or nuclear translocation of regulatory Smad2/3 but increased the expression of inhibitory Smad6.
Conclusions:
PKA pathway activation is involved in PVR pathogenesis, and the PKA inhibitor H89 can effectively inhibit PVR, both in vivo and in vitro. Furthermore, the protective effect of H89 is related to an increase in inhibitory Smad6.
Insights
The protein kinase A (PKA) pathway is implicated in proliferative vitreoretinopathy (PVR). The PKA inhibitor H89 effectively treats experimental PVR by increasing inhibitory Smad6, offering a potential therapeutic strategy.
Area of Science:
- Ophthalmology
- Molecular Biology
- Cell Biology
Background:
- Proliferative vitreoretinopathy (PVR) is a severe complication of retinal detachment, characterized by the formation of epiretinal membranes.
- The underlying molecular mechanisms of PVR pathogenesis, particularly the role of specific signaling pathways, require further elucidation.
- Identifying novel therapeutic targets is crucial for improving PVR treatment outcomes.
Purpose of the Study:
- To investigate the involvement of the protein kinase A (PKA) pathway in the development of PVR.
- To evaluate the therapeutic potential of the PKA inhibitor H89 in experimental models of PVR.
- To elucidate the molecular mechanisms by which H89 exerts its effects on PVR.
Main Methods:
- Analysis of PKA activation in human epiretinal membranes from PVR patients.
- Establishment of an in vivo rat model of PVR using ARPE-19 cells and platelet-rich plasma.
- Development of an in vitro epithelial-mesenchymal transition (EMT) model using TGF-β stimulation of ARPE-19 cells.
- Assessment of H89's effects on PVR pathology, vision function, EMT markers, and the TGF-β-Smad signaling pathway.
Main Results:
- PKA was found to be activated in human PVR membranes.
- In vivo, H89 treatment preserved retinal structure and electroretinogram function.
- In vitro, H89 inhibited TGF-β-induced EMT, blocked PKA activation, and increased the expression of inhibitory Smad6 without affecting Smad2/3 phosphorylation or nuclear translocation.
Conclusions:
- The PKA pathway plays a significant role in PVR pathogenesis.
- The PKA inhibitor H89 demonstrates significant therapeutic efficacy in both in vivo and in vitro models of PVR.
- H89's protective effects are mediated, at least in part, by the upregulation of inhibitory Smad6.
