YAP is essential for TGF‐β‐induced retinal fibrosis in diabetic rats via promoting the fibrogenic activity of Müller cells

• Published in: Journal of cellular and molecular medicine Vol. 24; no. 21; pp. 12390 - 12400
• Main Authors: Zhang, Wei, Kong, Yichun
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.11.2020; John Wiley and Sons Inc
• Subjects: 1-Phosphatidylinositol 3-kinase; AKT protein; Antibodies; Biotechnology; Cell proliferation; Diabetes; Diabetes mellitus; Diabetic retinopathy; Extracellular matrix; Fibroblasts; Fibrosis; Growth factors; Hydrogels; Immunohistochemistry; Kinases; Medical research; Original; Proteins; Retina; Retinal detachment; retinal Müller cells; Signal transduction; Transforming growth factor-b; Transforming growth factor-b1; transforming growth factor‐β; Western blotting; Wound healing; Yes-associated protein; United States > US; Yes-associated protein; fibrosis; retinal Müller cells; retina; transforming growth factor-β
• ISSN: 1582-1838; 1582-4934
• DOI: 10.1111/jcmm.15739

The purpose of this study was to investigate whether Yes‐associated protein (YAP) activation and proliferation of retinal Müller cells play a role in the development of TGF‐β‐induced retinal fibrosis. We studied the effects of YAP activation on retinal fibrosis in diabetic rats and human retinal Müller cells (hMCs) in vitro. The retinal expression of YAP and fibrogenic molecules in rats was detected using Western blotting and immunohistochemistry. After treatment with transforming growth factor‐β1 (TGF‐β1), the levels of fibrogenic molecules, and the activation of YAP and PI3K/Akt signalling pathway in hMCs were detected with Western blotting. The effect of YAP on retinal fibrotic changes was evaluated using YAP knockdown experiments and YAP inhibitors. Results showed that YAP expression was increased in the retina of diabetic rats along with increased retinal fibrosis. In cultured hMCs, YAP inhibition suppressed TGF‐β1‐stimulated hMC differentiation to myofibroblasts and extracellular matrix (ECM) production, while YAP activation promoted hMC differentiation and ECM production independent of TGF‐β1. Furthermore, hMCs cultured on a gel with greater stiffness differentiated into myofibroblasts in a YAP‐dependent manner. In diabetic rats, treatment with the YAP inhibitor verteporfin suppressed retinal fibrogenesis. In addition, the TGF‐β1‐induced PI3K/Akt signalling pathway mediated YAP activation as well as expression of fibrogenic molecules. The interaction between ECM stiffness and YAP forms a feed‐forward process leading to retinal fibrosis. Our work highlights YAP as an essential regulator of pro‐fibrotic responses in TGF‐β‐induced retinal fibrosis.