Suppression of Epithelial-Mesenchymal Transition in Retinal Pigment Epithelial Cells by an MRTF-A Inhibitor.

Abstract

Purpose:

Epithelial-mesenchymal transition (EMT) in retinal pigment epithelial (RPE) cells is related to the pathogenesis of subretinal fibrosis such as that associated with macular degeneration. The role of myocardin-related transcription factor A (MRTF-A) in EMT of RPE cells and subretinal fibrosis was investigated.

Methods:

The migratory activity of human RPE-1 cells in culture was evaluated using a scratch assay. The subcellular distribution of MRTF-A in RPE-1 cells, as well as the extent of subretinal fibrosis in a mouse model, were determined by immunofluorescence analysis. Expression of α-smooth muscle actin (α-SMA), collagen type I (COL1), connective tissue growth factor (CTGF), and paxillin was examined by immunoblot analysis or reverse transcription and quantitative polymerase chain reaction analysis, whereas that of pro-matrix metalloproteinase-2 (MMP-2) was assessed by gelatin zymography.

Results:

The MRTF-A signaling inhibitor CCG-1423 suppressed RPE-1 cell migration in a concentration-dependent manner. Transforming growth factor-beta (TGF-β2) induced MRTF-A translocation from the cytoplasm to the nucleus of RPE-1 cells, and this effect was attenuated by CCG-1423. TGF-β2 up-regulated the abundance of α-SMA, paxillin, and pro-MMP-2 proteins as well as the amounts of α-SMA, COL1, and CTGF mRNAs in a manner sensitive to inhibition by CCG-1423. Finally, intravitreal injection of CCG-1423 markedly attenuated the development of subretinal fibrosis induced by photocoagulation in vivo.

Conclusions:

Our results implicate MRTF-A in EMT of RPE cells and in the development of subretinal fibrosis in vivo, suggesting that MRTF-A is a potential therapeutic target for retinal diseases characterized by subretinal fibrosis.

• Authors: Masaaki Kobayashi, Kazuhiro Tokuda, Yuka Kobayashi, Chiemi Yamashiro, Sho-Hei Uchi, Makoto Hatano, Kazuhiro Kimura
• Journal: Investigative ophthalmology & visual science (Invest Ophthalmol Vis Sci) Vol. 60 Issue 2 Pg. 528-537 (02 01 2019) ISSN: 1552-5783 [Electronic] United States
• PMID: 30707754 (Publication Type: Journal Article)

Chemical References

• ACTA2 protein, human
• Actins
• Anilides
• Benzamides
• CCG 1423
• CCN2 protein, human
• Collagen Type I
• MRTFA protein, human
• Trans-Activators
• Connective Tissue Growth Factor
• Matrix Metalloproteinase 2

Topics

• Actins (metabolism)
• Anilides (pharmacology)
• Animals
• Benzamides (pharmacology)
• Cell Movement (physiology)
• Collagen Type I (metabolism)
• Connective Tissue Growth Factor (metabolism)
• Disease Models, Animal
• Dose-Response Relationship, Drug
• Epithelial-Mesenchymal Transition (physiology)
• Female
• Fibrosis
• Fluorescent Antibody Technique, Indirect
• Humans
• Matrix Metalloproteinase 2 (metabolism)
• Mice
• Mice, Inbred C57BL
• Real-Time Polymerase Chain Reaction
• Retina (pathology)
• Retinal Pigment Epithelium (metabolism)
• Trans-Activators (antagonists & inhibitors, metabolism)