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Abstract #11757 Published in IGR 7-1
Transforming growth factor-beta 2 modulated extracellular matrix component expression in cultured human optic nerve head astrocytes
Fuchshofer R; Birke M; Welge-Lussen U; Kook D; Lutjen-Drecoll EInvestigative Ophthalmology and Visual Science 2005; 46: 568-578
See also comment(s) by Rosario Hernandez • James Lindsey •
PURPOSE: To study whether glaucomatous extracellular matrix (ECM) modifications in the lamina cribrosa might be induced by TGF-β2 , the effect of TGF-β2 on the expression of collagen types I (Col1 alpha 1), III (Col3 alpha 1), and IV (Col4 alpha 2); fibronectin (FN); tissue transglutaminase (TGM2); connective tissue growth factor (CTGF); and thrombospondin (TSP-1) in cultured human optic nerve head (ONH) astrocytes was investigated. METHODS: Astrocytes were isolated from eyes of five human donors, and cultured monolayers were treated with 1.0 ng/mL TGF-β2 for 24 and 48 hours. Expression of Col1 alpha 1, Col3 alpha 1, Col4 alpha 2, FN, TGM2, CTGF, and TSP-1 was examined by semiquantitative RT-PCR and Northern and Western blot analyses. The effect of CTGF silencing on the TGF-β2 -modulated expression of these genes was investigated by transfection of CTGF small interfering (si)RNA before TGF-β2 treatment. RESULTS: TGF-β2 treatment upregulated the expression of Col1 alpha 1, Col4 alpha 2, FN, CTGF, TGM2, and TSP-1 mRNA and protein in cultured astrocytes. Inductions ranged between 1.5- and 4-fold. Expression of Col3 alpha 1 remained unaffected. Transfection of 10 nM CTGF siRNA inhibited the TGF-β2 -induced upregulation of CTGF, Col4 alpha 2, Col1 alpha 1, TGM2, and FN, whereas TSP-1 expression was not reduced. CONCLUSIONS: TGF-β2 is capable of inducing the expression of ECM and basement membrane components in cultured ONH astrocytes via CTGF and upregulated TSP-1, a protein naturally involved in the activation of latent TGF-beta. Therefore, TGF-β2 could be a factor in the initiation of the modification of ECM in the glaucomatous ONH. In addition, TSP-1 induction may be a mechanism by which TGF-β2 amplifies its own activation.
Dr. R. Fuchshofer, Department of Anatomy II, Friedrich Alexander University, Erlangen, Germany
Classification:
1.3 Pathogenesis (Part of: 1 General aspects)
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
3.3 Immunohistochemistry (Part of: 3 Laboratory methods)