YAP/TAZ Are Essential for TGF-β2–Mediated Conjunctival Fibrosis

Abstract

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.

Transforming growth factor beta induces fibroblasts to express and release the immunomodulatory protein PD‐L1 into extracellular vesicles

“…A common mediator of profibrotic responses is the transcriptional comodulators YAP and TAZ . In that YAP/TAZ has been shown to regulate metabolic activity as well as many aspects of the fibroblast response to TGFβ, we next addressed whether YAP/TAZ might be a mediator of PD‐L1 expression downstream of TGFβ signaling. YAP/TAZ levels were decreased using siRNA and PD‐L1 expression was assessed after TGFβ treatment.…”

“…A common mediator of profibrotic responses is the transcriptional comodulators YAP and TAZ. 42 In that YAP/TAZ has been shown to regulate metabolic activity 43 as well as many aspects of the fibroblast response to TGFβ, [44][45][46] we next addressed whether YAP/TAZ might be a mediator of PD-L1 1) and murine (AKR-2B and Swiss 3T3) fibroblast cell lines were stimulated with 5 ng/mL TGFβ (+) or Vehicle (−; 4 Mm HCl + 0.1% BSA) for 18 hours and Western blotted for PD-L1 or GAPDH. B, (Top) MRC5 and AKR-2B cells were stimulated with Vehicle (−) or TGFβ (+) and assessed for PD-L1, collagen 1 (COL1α1), and pSmad3 protein at the indicated times.…”

GPCR-induced YAP activation sensitizes fibroblasts to profibrotic activity of TGFβ1

“…Being potentially relevant to fibrosis, activated YAP/TAZ proteins are translocated to the nucleus where they crosstalk with the TGFβ pathway on a transcriptional level by binding to Smad2/3/4 complexes, as initially discovered in human and mouse embryonic stem cells, mammary epithelial cells, malignant mesothelioma and breast cancer cell lines [14][15][16][17]. It was shown that YAP/TAZ knockdown blocks the profibrotic effects of TGFβ1 [18,19] and TGFβ2 [20] and that substrate stiffness, which impacts YAP/TAZ localization and activity also regulates the output of the TGFβ1 pathway [21].…”

Downregulation of microRNA-224-3p Hampers Retinoblastoma Progression via Activation of the Hippo-YAP Signaling Pathway by Increasing LATS2

“…The expression of YAP, TAZ, CYGF, and CYR61 was decreased when LATS2 was overexpressed, which was consistent with the aforementioned research. CCN family proteins including CYR61 and CTGF, which depend on both YAP and TAZ, 35 have been identified to play important roles in skeletal growth, wound cure, fibrosis, and cancer. 36 Wang et al 37 identified the crucial roles of YAP and TAZ in the regulation of vascular homeostasis.…”