Purchase this article with an account.
Andrew J O Smith, Sarah Gardner, David Griggs, Michael Wormstone; Elucidating the role of αV integrin in TGFβ1 mediated fibrotic responses: implications for PCO. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2648.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Posterior capsule opacification (PCO) is a major complication of cataract surgery leading to secondary loss of vision. It results from fibrotic changes that occur due to transforming growth factor β (TGFβ) signalling induced as a consequence of a wound healing response prompted by cataract surgery. TGFβ is produced in a latent form which must first be activated. Here, we investigate the role of αV integrin in the activation of TGFβ1 in the human lens, and its involvement in PCO.
The human lens epithelial cell line FHL124 and an in vitro human capsular bag model were used as the experimental systems. Latent TGFβ1 was added at 10ng/ml and αv integrins were inhibited by a small molecule CWHM-12 (10µM). Western blot and immunocytochemistry were used to assess the myofibroblast cell marker, α-smooth muscle actin (αSMA), expression. A patch assay was used to measure FHL124 cell contraction. Cell growth across and modification of the central posterior capsule of capsular bags was observed by phase contrast microscopy over a 28 day culture period. Capsular contraction was determined using image analysis software. Active TGFβ1 levels within culture medium were measured by ELISA.
Addition of latent TGFβ1 to capsular bag cultures resulted in elevated levels of active TGFβ1, and a moderate increase in matrix contraction and αSMA levels at end-point (day 28). No significant difference in cell growth was seen. Addition of latent TGFβ1 to FHL124 cells resulted in a significant increase in αSMA expression. Treatment of capsular bags with CWHM-12 or control compound (CWHM-96) in the presence of latent TGFβ1 did not reveal any difference in levels of active TGFβ1 in the medium or αSMA levels (at end-point) relative to control, but a clear increase in matrix contraction was observed. FHL124 cells pre-treated for 1 hour with CWHM-12 followed by latent TGFβ1 exposure displayed a reduction in αSMA expression compared to CWHM-96 control cells. In terms of contraction, FHL124 cells treated with CWHM-12 alone demonstrated contraction, without a significant loss of cells. This response was enhanced when latent TGFβ1 was added.
αV integrins are not essential for activation of latent TGFβ1 in human lens epithelial cells. αV integrins appear to play an important role in promoting TGFβ1 induced transdifferentiation, but conversely have an inhibitory function with regard to matrix contraction.
This PDF is available to Subscribers Only