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Title: | ROLE OF MYOCARDIN RELATED TRANSCRIPTION FACTOR-A IN TRANSCRIPTION GROWTH FACTOR BETA-INDUCED EPITHELIAL TO MESENCHYMAL TRANSITION OF LENS EPITHELIAL CELLS |
Other Titles: | ROLE OF MRTF-A IN EPITHELIAL TO MESENCHYMAL TRANSITION IN THE LENS |
Authors: | Gupta, Madhuja |
Advisor: | West-Mays, Judith |
Department: | Biomedical Engineering |
Keywords: | Lens, PCO, EMT, MRTF-A, TGFβ, MMP, αSMA |
Publication Date: | Jun-2015 |
Abstract: | Transcription growth factor beta (TGFβ) mediated epithelial to mesenchymal transition (EMT) of lens epithelial cells (LEC) is known to cause posterior capsular opacification (PCO). In this work, I have focused on the TGFβ-induced EMT pathway governed by the cellular actin cytoskeleton dynamics. This study is the first to report the involvement of transcription co-factor myocardin related transcription factor-A (MRTF-A) in TGFβ-induced EMT in the lens. Using rat lens epithelial explants, I have conclusively established that in LECs, TGFβ induces nuclear migration of MRTF-A leading to induction of αSMA expression. Furthermore, I have manipulated the intracellular translocation of MRTF-A indirectly using actin binding drugs and established that inhibiting nuclear migration of MRTF-A reduces αSMA production by the cells. In addition, direct manipulation of MRTF-A using adenoviral vectors carrying modified gene constructs show that presence of functional MRTF-A construct in the nucleus is necessary to trigger αSMA expression by causing EMT. In order to understand the involvement of matrix metalloproteinase -9 (MMP-9) in this specific pathway, explants were treated with an MMP2/9 inhibitor and rhMMP9. I have established that rhMMP-9 does not significantly affect the intracellular migration of MRTF-A. Nevertheless, gene expression studies showed that MMP-9 induces the expression of MRTF-A. Taken together, I believe MMP-9 functions through a feedback mechanism controlling MRTF-A expression in the cell. However, the presence of MMP-9 is necessary but not sufficient for induction in MRTF-A nuclear translocation. Overall, the work presented in this thesis demonstrates for the first time the presence of MRTF-A in LECs and successfully shows that the intracellular translocation of MRTF-A as an integral part of TGFβ induced EMT. Therefore, in the future, MRTF-A may be used as a successful target molecule to inhibit in order to prevent EMT leading to PCO. |
URI: | http://hdl.handle.net/11375/16524 |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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PhD_FIN.pdf | THESIS | 72.38 MB | Adobe PDF | View/Open |
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