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Abstract #54671 Published in IGR 15-3
Effects of TGF-β2 on cadherins and β-catenin in human trabecular meshwork cells
Wecker T; Han H; Bö,rner J; Grehn F; Schlunck GInvestigative Ophthalmology and Visual Science 2013; 54: 6456-6462
PURPOSE: The effects of TGF-β2 on cadherin-mediated cell-cell adhesion in human trabecular meshwork (HTM) cells were characterized, since TGF-β-induced changes in the cytoskeleton, cell-cell, and cell-matrix interactions of HTM cells are suggested to have a significant role in primary open angle glaucoma. METHODS: The HTM cells were derived from donor cornea rings and treated with TGF-β2 or vehicle, and protein expression was studied by Western Blot, while protein localization was studied by fractionation of lysates and by confocal immunofluorescence microscopy. Cell-cell adhesion was assessed functionally in dissociation experiments and N-cadherin-mediated cell contact formation in cell spreading experiments on cadherin-coated substrates. A rho-associated protein kinase (ROCK) inhibitor was used to evaluate the contribution of cytoskeletal tension to TGF-β2-induced changes in protein expression and localization. RESULTS: TGF-β2 activated Smad-2/3, serine-threonine kinase (AKT), and extracellular signal-regulated kinase (ERK) signaling, and enhanced expression of β-catenin as well as N- and OB-cadherin. The nuclear fraction of β-catenin was not enhanced by TGF-β2. Immunofluorescence microscopy revealed an increased localization of N-cadherin and β-catenin to cell-cell adhesions, and an increase in F-actin. The TGF-β2 increased cell-cell adhesion strength and enhanced N-cadherin-mediated cell contact formation. This effect was blocked by inhibition of mitogen-activated protein kinase kinase (MEK) or AKT. Cytoskeletal relaxation by a ROCK inhibitor did not prevent a TGF-β2-induced increase in cadherin and β-catenin expression. CONCLUSIONS: The cytokine TGF-β2 enhances cadherin-mediated cell-cell adhesion and β-catenin expression in HTM cells. Increased cell-cell adhesion may contribute to biomechanical alterations in glaucomatous trabecular meshwork (TM), and changes in β-catenin levels and its possible sequestration to cell adhesion sites may affect Wnt signaling. Thus, the crosstalk of TGF-β2 and Wnt signaling in TM may deserve further investigation.
Department of Ophthalmology, Freiburg University Medical Center, Freiburg, Germany.
Full articleClassification:
2.5.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.5 Meshwork)
3.6 Cellular biology (Part of: 3 Laboratory methods)
3.3 Immunohistochemistry (Part of: 3 Laboratory methods)
3.8 Pharmacology (Part of: 3 Laboratory methods)
