Alteration of transforming growth factor-beta1 response involves down-regulation of Smad3 signaling in myofibroblasts from skin fibrosis.

Fibrosis is an unregulated tissue repair process whose predominant characteristics are the proliferation of myofibroblasts and an excessive deposition of extracellular matrix. Transforming growth factor (TGF)-beta1 is considered as one of the most fibrogenic cytokines. However, the molecular mechanisms involved in its profibrotic role are not fully understood.