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Suppression of injury-induced epithelial-mesenchymal transition in a mouse lens epithelium lacking tenascin-C

PURPOSE: To investigate the role of tenascin-C in epithelial-mesenchymal transition (EMT) of the lens epithelium during wound healing in mice. Tenascin-C is a component of the extracellular matrix in patients having post-operative capsular opacification. METHODS: The crystalline lens was injured by...

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Detalles Bibliográficos
Autores principales: Tanaka, Sai-ichi, Sumioka, Takayoshi, Fujita, Norihito, Kitano, Ai, Okada, Yuka, Yamanaka, Osamu, Flanders, Kathleen C., Miyajima, Masayasu, Saika, Shizuya
Formato: Texto
Lenguaje:English
Publicado: Molecular Vision 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901186/
https://www.ncbi.nlm.nih.gov/pubmed/20664686
Descripción
Sumario:PURPOSE: To investigate the role of tenascin-C in epithelial-mesenchymal transition (EMT) of the lens epithelium during wound healing in mice. Tenascin-C is a component of the extracellular matrix in patients having post-operative capsular opacification. METHODS: The crystalline lens was injured by needle puncture in tenascin-C null (KO, n=56) and wild-type (WT, n=56) mice in a C57BL/6 background. The animals were killed at day 2, 5, or 10 post-injury. Immunohistochemistry was employed to detect α-smooth muscle actin (αSMA), a marker of EMT, collagen type I, transforming growth factor β1 (TGFβ1), phospho-Smad2, phospho-adducin, and phospho-myosin light chain 9 (MLC9). The expression levels of phospho-adducin and phospho-MLC9 were used as markers for the activation of protein kinase C and Rho kinase, respectively. RESULTS: The expression of tenascin-C was upregulated in WT lens epithelial cells adjacent to the capsular break at day 5. The results showed that injury-induced EMT of the mouse lens epithelium, as evaluated by histology and the expression patterns of αSMA and fibronectin, was attenuated in the absence of tenascin-C. Upregulation of TGFβ1 expression in the epithelium was also inhibited, and loss of tenascin-C attenuated the phosphorylation of Smad2 and adducin in epithelial cells adjacent to the capsular break. The expression of phospho-adducin was suppressed, while the expression level of phospho-MLC9 was unchanged, in the healing epithelium in the absence of tenascin C. CONCLUSIONS: Tenascin-C is required for injury-induced EMT in the mouse lens epithelium. The mechanism behind this might involve impaired activation of cytoplasmic signaling cascades; i.e., TGFβ/Smad and protein kinase C-adducing signaling, in the absence of tenascin-C.