Fibrosin, a novel fibrogenic cytokine, modulates expression of myofibroblasts.

Granulation tissue fibroblasts, or myofibroblasts are characterized by the presence of alpha smooth muscle actin fibers (alpha SMA). These specialized cells are involved in wound contraction and in retractile phenomena observed during fibrotic disease. Myofibroblasts have also been shown to play a role in embryonic development. Growth factors such as Transforming growth factor beta TGFbeta and Nerve growth factor (NGF) can modulate the differentiation of myofibroblasts. In this report, we show that in vitro application of fibrosin, a novel fibrogenic cytokine, stimulates expression of alpha SMA-producing cells at least four-fold above that observed in control cultures. In addition, administration of fibrosin in a wound healing model in mice stimulates increased numbers of myofibroblasts 7 days after injury, when compared with untreated, or, control, wounded mice. These results suggest that fibrosin plays an important role in up regulating the appearance of myofibroblasts during wound healing, and possibly in fibrotic diseases. It may, therefore, be important in the process of scarring.