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Abstract #13274 Published in IGR 8-1
Induction of TGF-β1 in the trabecular meshwork under cyclic mechanical stress
Liton PB; Liu X; Challa P; Epstein DL; Gonzalez PJournal of Cellular Physiology 2005; 205: 364-371
See also comment(s) by Jonathan Crowston •
The pathophysiological mechanisms involved in the failure of the trabecular meshwork (TM) to maintain normal levels of aqueous outflow in glaucoma are not yet understood. Aberrant activation of the transforming growth factor beta-1 (TGF-β1) pathway has been implicated in several degenerative diseases. We investigated the possibility that chronic cyclic mechanical stress that affects the TM might result in increased production of TGF-β1. Primary cultures of TM cells subjected to cyclic mechanical stress (5% stretching, 1 cycle/sec) demonstrate a significant increase in total and biologically active secreted TGF-β1 that was associated with activation of the TGF-β1 promoter, measured using a recombinant adenovirus expressing the secreted reporter gene secreted alkaline phosphatase protein (SEAP) under the TGF-β1 gene promoter (AdTGFβ1-SEAP). Associated changes in the transcription of MMP-2, TIMP-2, and CTGF were assessed by semiquantitative PCR. Immunohistochemical analysis of TGF-β1 in organ culture of human eyes revealed a generalized accumulation of this protein in the extracellular matrix (ECM) of the TM, while expression of the TGF-β1 promoter, analyzed using the LacZ reporter gene, was localized in some specific cells within the outflow pathway. Induction of the TGF-β1 promoter in organ culture was demonstrated using a novel model for cyclic mechanical stress in human perfused anterior segments infected with AdTGFβ1-SEAP. Given the relevant physiological and pathophysiological roles of TGF-β1, its induction after cyclic mechanical stress in the TM supports the hypothesis that this cytokine might play a significant role in the physiology of the TM, and contribute to the pathological changes of this tissue in certain forms of glaucoma.
Dr. P. Gonzalez, Duke University Eye Center, Box 3802, Erwin Road, Durham, NC 27710, USA
Classification:
2.5.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.5 Meshwork)
3.3 Immunohistochemistry (Part of: 3 Laboratory methods)
3.5 Molecular biology incl. SiRNA (Part of: 3 Laboratory methods)
