PURPOSE. To investigate the roles of Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ), the major effector molecules of the Hippo pathway, in TGFb2-mediated conjunctival fibrosis.METHODS. Primary human conjunctival fibroblasts were treated with TGF-b2. The expression of YAP/TAZ was examined by Western blot analyses and immunocytochemistry. The expression of fibrotic proteins and genes were evaluated by Western blot analyses and quantitative real-time PCR, respectively. The effects of YAP/TAZ on fibrotic changes were examined by knockdown experiments and the YAP/TAZ inhibitor, verteporfin.RESULTS. TGF-b2 stabilized YAP/TAZ and subsequently activated Smad2/3, which led to the transcription of fibrotic genes in human primary conjunctival fibroblasts. These fibrotic genes were differently regulated by YAP/TAZ. Notably, a-smooth muscle actin, fibronectin, collagen I, and collagen IV were primarily regulated by YAP. In contrast, CCN family proteins (CTGF and CYR61) depended on both YAP and TAZ. Mechanistically, YAP/TAZ were located in close proximity to Smad2/3, and in particular, YAP was required for TGF-b2-mediated phosphorylation and the nuclear translocation of Smad2/3. Furthermore, a YAP/TAZ inhibitor markedly suppressed TGF-b2-mediated fibrotic changes in conjunctival fibroblasts.CONCLUSIONS. YAP/TAZ acted as a molecular hub of TGF-b2 signaling in a cellular model of conjunctival fibrosis. Moreover, verteporfin, a YAP/TAZ inhibitor exerted potent antifibrosis effects by suppressing TGF-b2-YAP/TAZ-Smad signaling. Our study highlights YAP/TAZ as essential regulators of conjunctival fibrosis and shows that inhibition of YAP/TAZ might potentially improve the outcomes of glaucoma filtration surgery.

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Glaucoma is one of the major causes of blindness, and transforming growth factor-β2 (TGF-β2) has been found to be elevated in the aqueous humor of eyes with primary open-angle glaucoma (POAG). TGF-β2 in aqueous humor causes the glaucoma-related fibrosis of human trabecular meshwork (HTM), suggesting an important role of TGF-β in POAG pathogenesis. Here, we sought to elucidate the effects of IL-6 trans-signaling on TGF-β signaling in HTM cells. Using a multiplex immunoassay, POAG patients decreased IL-6 levels and increased soluble IL-6 receptor (sIL-6R) levels compared with the controls. In experiments, we observed that the IL-6 level was increased in the conditioned medium of HTM cells after TGF-β2 stimulation. To elucidate the relationship between TGF-β2 and IL-6 in HTM cells, we conducted Western blotting and immunohistochemical analyses, and we noted that the combination of IL-6 and sIL-6R (IL6/sIL-6R) suppressed TGF-β-induced up-regulation of α-smooth muscle actin in HTM cells, whereas IL-6 alone did not. This suggests that trans-signaling, not classic signaling, of IL-6 suppresses TGF-β-induced fibrosis of HTM. IL6/sIL-6R also suppressed TGF-β-mediated activation of myosin light chain 2 (MLC2), Smad2, and p38. Of note, these inhibitory effects of IL6/sIL-6R on TGF-β were partly reduced by siRNA-mediated knockdown of STAT3. Moreover, IL-6/sIL-6R partly inhibited TGF-β-induced activation of the Smad-sensitive promoter detected with luciferase reporter gene assays and up-regulation of TGFRI and TGFRII, evaluated by quantitative real-time RT-PCR. Strikingly, overexpression of TGFRI and TGFRII diminished these inhibitory effects of IL-6/sIL-6R. We conclude that of IL-6-mediated trans-signaling potently represses TGF-β signaling in HTM cells.

ROCKS study group collaborators † To evaluate the efficacy and safety of ripasudil for treatment of secondary glaucoma, a historical cohort study was conducted at 18 centres in Japan. Adults (age ≥20 years) who needed additional IOP reduction and received topical 0.4% ripasudil between 2014 and 2018 due to three secondary glaucoma subtypes, including uveitic glaucoma (UG), exfoliation glaucoma (EG) or steroid-induced glaucoma (SG) were assessed for mean IOP change from baseline prior to additional treatment with ripasudil. We further evaluated the IOP change in each glaucoma subtype, baseline characteristics of each cohort, course of uveitis-induced inflammation in UG eyes, and proportion of patients in each cohort with adverse events. In 332 eyes from 332 patients eligible for this study, the mean overall IOP reductions from baseline at 1, 3, and 6 months were −5.86 ± 9.04 mmHg (−19.4 ± 25.1%), −6.18 ± 9.03 mmHg (−20.0 ± 27.1%), and −7.00 ± 8.60 mmHg (−23.4 ± 25.6%), respectively. These changes were all statistically significant. Of 332 eyes, 109 eyes had UG, 181 had EG, and 42 eyes had SG. The IOPlowering effects of ripasudil in UG and SG were significantly greater than those of EG at every time point. This finding could have been related to higher baseline IOP levels in UG and SG. UG patients exhibited significant decreases in mean cell score of the anterior segment after ripasudil treatment. No severe adverse events were reported. These findings suggest that treatment with ripasudil is a safe and effective therapeutic modality for IOP reduction in secondary glaucoma. The Rho protein contributes to various physiological events in many organs and tissues. Rho and its effector molecule Rho-associated kinase (ROCK) are involved in diverse cellular functions, including stress fibre formation, focal adhesion, cell contraction, motility and polarity 1-3. Rho/ROCK signalling molecules are present in the aqueous outflow pathway 4,5 , and regulate aqueous humour outflow, contributing to the pathologies of some subtypes of glaucoma 6,7. Rho/ROCK inhibition lowers intraocular pressure (IOP) primarily by increasing aqueous humour outflow directly through the conventional pathway, which is comprised of the trabecular meshwork (TM) and Schlemm's canal (SC) 8-11. ROCK inhibitors have been shown to induce alterations in cell shape, contraction, motility, attachment and extracellular matrix production in TM and SC cells 10. Moreover, several recent studies have demonstrated anti-inflammatory effects of ROCK inhibitors such as ripasudil 12,13 , including inhibition of immune cell infiltration and inflammatory cytokine production.

Purpose This study aimed to investigate the effects of substratum stiffness on the sensitivity of human conjunctival fibroblasts to transforming growth factor (TGF)-β, and to explore the molecular mechanism of action. Methods Human conjunctival fibroblasts were cultured on collagen-coated plastic or silicone plates. The stiffness of the silicone plates was 0.2 or 64 kPa. Cells were treated by 2.5 ng/mL TGF-β2 with or without fibroblast growth factor (FGF)-2 (0–100 ng/mL) for 24 h or 48 h. The protein expression levels were determined by Western blot analysis. Cell proliferation was assessed using the WST-8 assay. Results FGF-2 suppressed the TGF-β-induced expression of α-smooth muscle actin (SMA) and collagen type I (Col I), but not fibronectin (FN). Both FGF-2 and TGF-β2 increased cell proliferation without an additive effect. The induction of α-SMA by TGF-β2 was decreased on the soft substratum, without any change in the expression level or subcellular location of Yes-associated protein/transcriptional coactivator with PDZ-binding motif (YAP/TAZ). FGF-2 suppressed TGF-β-induced α-SMA expression even on the soft substratum. Conclusions FGF-2 treatment and a soft substratum suppressed TGF-β-induced transdifferentiation of conjunctival fibroblasts into myofibroblasts. FGF-2 attenuated the TGF-β-induced expression of α-SMA, even on a soft substratum.