Synergistic effects of TGF-β and ET-1 in fibroblast activation. Signal intensities from Western blots of fibroblasts isolated from co-cultures of HaCaT keratinocytes and fibroblasts after 7 days in Dulbecco's modified Eagle medium/0.5% foetal calf serum. α-Smooth muscle actin (α-SMA) expression increased in co-cultures (see lane 1) as compared with fibroblasts alone (compare dotted line). Addition of an anti-transforming growth factor (TGF)-β antibody or the endothelin (ET)-1 inhibitor PD 156252 resulted in reduced α-SMA expression. Addition of anti-TGF-β and PD 156252 blocked α-SMA expression to almost basal levels .
Krieg et al. Arthritis Research & Therapy 2007 9(Suppl 2):S4 doi:10.1186/ar2188