Fig. 3.

PDE1 inhibitors and PDE1A knockdown attenuates myofibroblast activation, ECM synthesis and pro-fibrotic gene expression. a Cardiac fibroblast activation assessed by α-SMA promoter luciferase activity in rat cardiac fibroblasts pre-treated with vehicle or IC86340 (30 μmol/L) prior to Ang II (100 nmol/L) stimulation for 24 h, and normalized to β-galactosidase activity. b Cardiac fibroblasts transduced with 100 MOI Ad-LacZ shRNA or Ad-PDE1A shRNA and stimulated as described above. c Collagen synthesis measured via of [³H]-proline incorporation in cardiac fibroblasts pre-treated with vehicle or IC86340 prior to Ang II stimulation for 48 h, and normalized to total protein levels. d Cardiac fibroblasts transduced with Ad-LacZ shRNA or Ad-PDE1A shRNA and stimulated as described above. Values represent mean ± SD from three independent experiments performed in triplicates. *P < 0.05 versus Ctrl (Vehicle or LacZ shRNA), †P < 0.05 versus Ang II alone. e Representative RT-PCR results showing effects of the PDE1 inhibitor IC86340 on Ang II stimulated pro-fibrotic marker gene expression, including type I collagen (Col1a), fibronectin (Fn), plasminogen activator inhibitor 1 (PAI-1), and α-SMA. Similar results were observed from at least three independent experiments. f RT-PCR results showing effects of PDE1A shRNA versus LacZ shRNA on Ang II stimulated pro-fibrotic gene expression in cardiac fibroblasts. Similar results were observed from at least two independent experiments