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Michael Wormstone, Andrew J. O. Smith, Julie A. Eldred; The Rho kinase signaling pathway can facilitate TGFβ-mediated matrix contraction and transdifferentiation of human lens epithelial cells to myofibroblasts. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5638. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Transforming growth factor β (TGFβ) is believed to play a key role in the formation of posterior capsule opacification (PCO) following cataract surgery. In addition to the well-established Smad signaling pathway, TGFβ is reported to activate Smad-independent signaling pathways. In the current study we elected to determine the role of the Rho kinase pathway in TGFβ-mediated events relevant to PCO.
In vitro capsular bags were generated from human donor eyes by simulated cataract surgery, isolated by cutting of the zonules and secured to a 35mm tissue culture dish using entomological pins. Match-paired capsular bag experiments were performed and culture took place in 5% FCS supplemented EMEM. The capsulorhexis samples containing anterior lens epithelial cell were generated during simulated surgery and also secured to tissue culture dishes and maintained in the same conditions. Preparations were cultured for a 7 day period with experimental conditions. Observations were made using phase-contrast and modified darkfield microscopy. Immunocytochemistry was employed at end-point to assess the trans-differentiation marker, α-SMA and when relevant capsular wrinkling/matrix contraction was assessed using image analysis.
In control conditions, lens epithelial cells rapidly recolonized the central posterior capsule of capsular bags. When treated with 10ng/ml TGFβ2 capsular bags exhibited a significant increase in matrix contraction/wrinkling. End-point analysis also revealed a significant elevation αSMA. Treatment of capsular bag preparations with 10µM Y27632, a Rho kinase inhibitor, did not markedly affect cell coverage of the central posterior capsule, but did significantly reduced αSMA expression and matrix contraction. In capsulorhexis preparations, there was no evidence of matrix contraction in any treatment group. However, a marked increase in αSMA expression was observed in the presence of 10ng/ml TGFβ2. Again treatment with 10µM Y27632 significantly suppressed αSMA expression.
Rho kinase appears to play an important role in matrix contraction and transdifferentiation of lens epithelial cells to myofibroblasts. Targeting the Rho kinase signaling pathway could therefore serve as a useful strategy to improve the management of posterior capsule opacification and other fibrotic conditions within the eye.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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