Probing Embryonic Development Enables the Discovery of Unique Small-Molecule Bone Morphogenetic Protein Potentiators

We report on the
feasibility to harness embryonic development in vitro for the identification of small-molecule cytokine
mimetics and signaling activators. Here, a phenotypic, target-agnostic,
high-throughput assay is presented that probes bone morphogenetic
protein (BMP) signaling during mesodermal patterning of embryonic
stem cells. The temporal discrimination of BMP- and transforming growth
factor-β (TGFβ)-driven stages of cardiomyogenesis underpins
a selective, authentic orchestration of BMP cues that can be recapitulated
for the discovery of BMP activator chemotypes. Proof of concept is
shown from a chemical screen of 7000 compounds, provides a robust
hit validation workflow, and afforded 2,3-disubstituted 4H-chromen-4-ones as potent BMP potentiators with osteogenic efficacy.
Mechanistic studies suggest that Chromenone 1 enhances
canonical BMP outputs at the expense of TGFβ-Smads in an unprecedented
manner. Pharmacophoric features were defined, providing a set of novel
chemical probes for various applications in (stem) cell biology, regenerative
medicine, and basic research on the BMP pathway.