Phosphotyrosine Signaling as a Regulator of Corneal Endothelial Cell Function
Date Issued
2005
Date
2005
Author(s)
Lo, Hung-Fei
DOI
zh-TW
Abstract
The importance of phosphotyrosine signal transduction in cellular proliferation, cell-cell contact and cellular migration has been proved in various cell types. However, only limited studies have been reported on corneal endothelial cell cells. In this study, we aim to understand the role of phosphotyrosine signaling in corneal endothelial cellular function. We propose that protein tyrosine phosphotase (PTP) may play an important role in cell-cell junction of corneal endothelial cells, and the disruption of its function by PTP inhibitor can break through cell-cell junction, and trigger a lot of downstream actions such as cellular proliferation and change of permeability. Primary culture of bovine corneal endothelial cells and whole rabbit corneas were used as the experimental materials. We first treated the cultured bovine corneal endothelial cells with PTPs inhibitor, sodium orthovanadate (SOV), with a variety of concentrations (25,50,100μM) for various durations (8,24 hrs). The effects of PTP inhibition on cellular distribution of cell-cell junctional proteins, such as N-cadherin, alpha-catenin and p120, were evaluated by immunohistochemical staining with fluorescein microscopy and confocal microscopy. Immunohistochemical staining with Ki67 Ab, a marker of cell proliferation, was also used to detect cells entering cell cycle. The expression levels of these cellular junctional proteins and regulatory proteins in cell cycle regulation such as Cyclin A, Cyclin E, Cyclin D1 and PCNA, were quantified by Western blotting. Our results demonstrate that PTPs inhibitor broke through cell-cell junction, and triggered corneal endothelial cells to re-enter cell cycle instead of having no impacts on celluar proliferation. However, the expression levels of those chosen cell-cell junction proteins and chosen regulatory proteins in cell cycle regulation were unchanged. Further studies will be carried out to elucidate the mechanism of phosphotyrosine signaling in mediating the cellular behavior of corneal endothelial cells.
Subjects
角膜
酪胺酸磷酸化
內皮細胞
訊息傳遞
磷酸化
cornea
PTPs
endothelium
signal transduction
phosphotyrosine
Type
thesis
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