Purchase this article with an account.
Dongmei Xing, Joseph A. Bonanno; Effect of cAMP on TGFβ1-Induced Corneal Keratocyte-Myofibroblast Transformation. Invest. Ophthalmol. Vis. Sci. 2009;50(2):626-633. doi: 10.1167/iovs.08-2444.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
purpose. TGFβ is the major mediator to induce myofibroblast differentiation in the corneal wound-healing process. Elevated cAMP can reduce TGFβ-induced fibrosis in other tissues. This study was conducted to determine whether elevated cAMP can inhibit TGFβ1-induced rabbit corneal keratocyte-myofibroblast transformation.
methods. Primary isolated rabbit corneal keratocytes were cultured in serum-free medium. The effects of the adenylate cyclase agonist forskolin (FSK; 2 μM) on TGFβ1 (5 ng/mL)-induced α-smooth muscle actin (α-SMA) expression was examined by immunofluorescence, flow cytometry, and immunochemistry 72 hours after treatment. The effects of TGFβ+FSK on activated pSmad3, CREB binding protein (CBP), MAPKs, and RhoA were determined by coimmunoprecipitation and Western blot.
results. FSK significantly reduced the myofibroblast phenotype and α-SMA expression induced by TGFβ1 in rabbit corneal keratocytes. TGFβ1 increased the phosphorylation of ERK and Smad3. TGFβ1-induced α-SMA expression was reduced by MEK inhibition (U0126); however, the levels of pERK, pSmad3, or the extent of the interaction between pSmad3 and CBP induced by TGFβ1 were not affected by FSK. TGFβ1 also activated RhoA and ROCK (Y27632) inhibition reduced α-SMA expression. Activation of RhoA was significantly reduced by FSK.
conclusions. Raising cAMP by FSK treatment inhibits the TGFβ1-induced corneal myofibroblast transformation and α-SMA expression and thereby provides a promising method to control corneal fibrosis. The data suggest that cAMP-dependent inhibition does not occur by altering Smads or MAPK signaling, but possibly by reducing the activation of RhoA.
This PDF is available to Subscribers Only