Transforming growth factor β and platelet-derived growth factor modulation of myofibroblast development from corneal fibroblasts in vitro

- Mature α-smooth muscle actin+ and desmin+ myofibroblasts develop from vimentin+ corneal fibroblasts in vitro.
- TGFβ and PDGF are important regulators of myofibroblast development.
- TGFβ blockade inhibits myofibroblast development in vitro.

The purpose of this study was to test the hypotheses that development of mature vimentin+/α-smooth muscle actin+/desmin+ (V+A+D+) myofibroblasts from corneal fibroblasts is regulated by transforming growth factor (TGF) β and platelet-derived growth factor (PDGF); and that myofibroblast development in vitro follows a similar developmental pathway as it does in vivo. Mouse corneal stromal fibroblasts (MSF) were isolated from the corneas of Swiss Webster mice and cultured in serum-free media augmented with DMEM/F12 and varying doses of TGFβ (0.1-2.0 ng/ml), with and without mouse PDGF-AA and/or PDGF-BB (2.0 ng/ml), to study the transition of the MSF to V+A+D+ myofibroblasts. The mean percentage of vimentin+, α-SMA+ and desmin+ cells was determined at each time point (2-15 days), with each growth factor concentration. MSF in vitro were noted to undergo the same developmental transition from V+A−D− to V+A+D− to V+A+D+ myofibroblasts as precursors undergo in vivo. TGFβ at a dose of 0.5 ng/ml and 1.0 ng/ml with 2.0 ng/ml PDGF-AA and 2.0 ng/ml PDGF-BB in DMEM/F12 serum-free media was optimal for the development of V+A+D+ myofibroblasts. This study defines optimal in vitro conditions to monitor the development of MSF into myofibroblasts. The combined effects of TGFβ and PDGF promote the full development of V+A+D+ myofibroblasts from MSF.