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Abstract #13744 Published in IGR 8-2
p38 inhibitors prevent TGF-β-induced myofibroblast transdifferentiation in human tenon fibroblasts
Meyer-Ter-Vehn T; Gebhardt S; Sebald W; Buttmann M; Grehn F; Schlunck G; Knaus PInvestigative Ophthalmology and Visual Science 2006; 47: 1500-1509
PURPOSE: The role of mitogen-activated protein kinase (MAPK) pathways in TGF-β-induced myofibroblast transdifferentiation of human tenon fibroblasts (HTFs) was investigated to identify potential pharmacologic targets for the inhibition of scarring after glaucoma surgery. METHODS: TGF-β-dependent activation of Smad2, p38, and Erk-1/2 was examined by Western blot analysis. TGF-β-induced mRNA expression of collagen Iα1, fibronectin, and the myofibroblast transdifferentiation marker α smooth muscle actin (α-SMA) was analyzed by real-time RT-PCR. α-SMA protein expression and subcellular distribution were determined by Western blot analysis and immunofluorescence cytochemistry. Fibroblast contractility was assessed in three-dimensional collagen gel contraction assays, stress fiber assembly with rhodamine-phalloidin stains, and confocal microscopy. Cell proliferation was measured with an MTT assay. Specific pharmacologic kinase inhibitors were used to characterize the involvement of MAPK-dependent pathways. RESULTS: TGF-β stimulation of HTF induced a rapid and transient activation of Smad2 and Erk, whereas p38 activation was biphasic and sustained. After 24 hours of TGF-β stimulation, increased levels of collagen Iα1, fibronectin, and α-SMA transcripts were detected. After three days of stimulation, HTF displayed increased α-SMA protein levels, enhanced contractility, and assembly of actin stress fibers. TGF-β also induced HTF proliferation. Specific p38 inhibitors prevented all these aspects of TGF-β-induced myofibroblastic transdifferentiation. CONCLUSIONS: Pharmacologic inhibition of p38 abrogates TGF-β-induced myofibroblast transdifferentiation, reduces extracellular matrix protein expression and HTF proliferation, and may therefore serve to inhibit scarring after glaucoma surgery.
Dr. T. Meyer-Ter-Vehn, Department of Ophthalmology, University of Würzburg, Germany. meyer_t3@augenklinik.uni-wuerzburg.de
Classification:
3.5 Molecular biology incl. SiRNA (Part of: 3 Laboratory methods)
3.8 Pharmacology (Part of: 3 Laboratory methods)
