THE ROLE OF VIMENTIN EXPRESSION IN MONOCYTE/MACROPHAGE DIFFERENTIATION
| Authors | |
|---|---|
| Year of publication | 2005 |
| Type | Article in Proceedings |
| Conference | XIII. Cytoskeletální Klub |
| MU Faculty or unit | |
| Citation | |
| Field | Genetics and molecular biology |
| Keywords | vimentin; monocyte/macrophage differentiation; phagocytosis; gene expression; siRNA |
| Description | Differentiation of various cells is accompanied by changes in expression of genes coding for intermediate filament (IF) proteins. These changes could be either qualitative causing a switch of expression to different type of IF protein or quantitative causing production of different amount of the same IF protein. During differentiation of hemopoietic cells dramatic changes in expression, intracellular localization and structural organization of vimentin occurs. Monocytes/macrophages are the only blood cells with fully developed vimentin network in cytoplasm. The aim of this study was to explore the role of vimentin expression during monocyte/macrophage differentiation using the v-myb-transformed monoblastic cell line (BM2) as a model. An increase of intracellular level of vimentin was confirmed during phorbol ester TPA or trichostatin A (TSA) induced differentiation of BM2 cells using western blotting. Moreover, we demonstrated the presence of fully developed network of vimentin in cytoplasm of differentiated BM2 cells using indirect immunoflourescence. We used siRNA strategy to prepare stable clones of BM2 cells with vimentin level reduced to 30%. At the same time, we prepared BM2 cells inducibly expressing this IF protein. We did not observed any difference in proliferation or in response to TPA or TSA in BM2 cells with increased expression of vimentin in comparison with BM2 control cells. In contrast, modest decrease in proliferation rate and marked reduction of ability to form macrophage polykaryons and decreased phagocytic activity upon TPA or TSA treatment were observed. These results demonstrate that alterations in expression and/or organization of vimentin network in cytoplasm are important pre-requisites for formation of fully functional macrophage polykaryons during monocyte/macrophage differentiation. |
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