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Alice L. Yu, Jerome Moriniere, Marco Birke, Carolin Neumann, Rudolf Fuchshofer, Anselm Kampik, Hans Bloemendal, Ulrich Welge-Lussen; Reactivation of Optic Nerve Head Astrocytes by TGF-β2 and H2O2 Is Accompanied by Increased Hsp32 and Hsp47 Expression. Invest. Ophthalmol. Vis. Sci. 2009;50(4):1707-1717. doi: 10.1167/iovs.08-1961.
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purpose. Histologic studies have previously demonstrated increased expression of small heat shock proteins (Hsps) in reactive optic nerve head (ONH) astrocytes of patients with glaucoma. Transforming growth factor (TGF)-β2 and hydrogen peroxide (H2O2) are known to induce ONH astrocyte reactivation. The goal of the present study was to determine whether new potentially involved Hsps, such as Hsp32, -47, -60, and -70, are expressed in the reactivation process of ONH astrocytes mediated by TGF-β2 and H2O2.
methods. Cultured human ONH astrocytes were treated with 1.0 ng/mL TGF-β2 for up to 48 hours. In addition, the cells were exposed to 100, 200, or 400 μM H2O2 for 1 hour. Expression of Hsp32, -47, -60, and -70 was examined by immunohistochemistry, real-time PCR, and Western blot analyses.
results. Treatment with TGF-β2 increased Hsp32 after 4 and 6 hours, whereas Hsp47 was upregulated after treatment with TGF-β2 for 12, 24, and 48 hours. Exposure of the cells to H2O2 could increase both Hsp32 and -47. No significant effects on the expression of Hsp60 and -70 were observed after treatment of the cells with TGF-β2 or H2O2.
conclusions. TGF-β2 increased Hsp32 after short-term treatment and Hsp47 after longer periods in cultured human ONH astrocytes. H2O2 increased both Hsp32 and -47 levels. No effects on Hsp60 and -70 levels were induced by TGF-β2 and H2O2. These results may provide further insights into the cellular stress responses of reactive human ONH astrocytes. Further extensive studies are needed to examine the potential roles of Hsps in the ONH of glaucomatous eyes.
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