Dorsomorphin and SB-431542 inhibit epicardial α-smooth muscle actin (SMA) expression. a–b) Epicardial/mesothelial cells (hereafter termed ‘epicardial cells’) treated with serum-free medium (hereafter termed ‘medium’) plus or minus growth factors serve as negative and positive controls for SMA expression. c) Epicardial cells stimulated with growth factors and treated with SB-431542 ablated SMA expression. d–h) Growth factor-stimulated cells treated with KA4541, BIO, Cyclopamine or XAV had no effect on SMA expression. i) Growth factor-stimulated cells treated with Dorsomorphin (DM) also strongly inhibited SMA expression. j) This information panel provides details about the SOMs tested in these studies. k) The structures of the small molecules tested in this study are presented here. [(Scale bar=50µm; Footnotes: A-(26), B-unpublished data, C-(41), D-(42), E-(43), F-(44), G-(30), H-(22) SFM=Medium; GF=Growth Factor Medium].