Fig. 6.

Vimentin promotes mesenchymal cell proliferation and paracrine EMT signaling in vitro. (A) The growth curve of VIM^−/− and WT MDF cells after transfected with different amounts of vectors encoding full-length vimentin (the total DNA per transfection was equalized with the control vector). Data are shown as mean ± SEM; n = 3. (B) Immunoblotting of vimentin, pERK1/2, total ERK1/2, and GAPDH expression of the cell lysates in A. (C and D) Western blotting of individual markers (C) and migration (D) of mouse keratinocytes growing in 6-d conditioned medium (D6) from VIM^−/− and WT MDFs transfected with the indicated amount of vimentin plasmids. Data are shown as means ± SEM; n = 3. (E) Scheme showing the working model. Vimentin has a profound effect on fibroblast proliferation, which activates both collagen production and TGF-β secretion. The active fibroblast TGF-β induces Slug–EMT signaling in keratinocytes, promoting EMT-like transdifferentiation and keratinocyte migration.