In vitro activity: LDN193189 potently inhibits BMP4-mediated Smad1, Smad5 and Smad8 activation with IC50 of 5 nM, and efficiently inhibits transcriptional activity of the BMP type I receptors ALK2 and ALK3 with IC50 of 5 nM and 30 nM, respectively. Furthermore, LDN193189 also shows the inhibitory effect on the transcriptional activity induced by either constitutively active ALK2R206H or ALK2Q207D mutant proteins. A recent study shows that LDN-193189 blocks the production of reactive oxygen species induced by oxidized LDL during atherogenesis in human aortic endothelial cells.

Kinase Assay: LDN193189 is a selective BMP type I receptor inhibitor, which efficiently inhibits ALK2 and ALK3 (IC50=5 nM and 30 nM, respectively), with weaker effects on ALK4, ALK5 and ALK7 (IC50≥500 nM).

Cell Assay: Mouse PASMCs grown are transiently transfected to 50% confluence in six-well plates with 0.3 μg Id1promoter luciferase reporter construct (BRE-Luc) in combination with 0.6 μg of plasmid expressing constitutively active forms of BMP type I receptors (caALK2, caALK3 or caALK6). For both reporter plasmids, 0.2 μg of pRL-TKRenilla luciferase are used to control for transfection efficiency. PASMCs are incubated with LDN193189 (2 nM-32 μM) or vehicle starting 1 h after transfection. Cell extracts are harvested and quantified relative promoter activity by the ratio of firefly to Renilla luciferase activity with the dual luciferase assay kit.

Bioorg Med Chem Lett. 2013 Jun 1;23(11):3248-52