y Triptonide is an Effective Inhibitor of Wnt Signaling

Canonical Wnt/β-catenin signaling plays important roles during vertebrate heart development and inhibition of this pathway has been shown to improve injured heart repair by promoting cardiac progenitor cells’ differentiation. Despite extensive research, to date, no approved Wnt inhibitors are available in clinic. Triptonide is a key bioactive small molecule identified in a traditional Chinese medicine named Tripterygium wilfordii Hook F., and its cellular target has not been identified. Here we showed that triptonide effectively inhibited canonical Wnt/β-catenin signaling by targeting a very downstream nuclear component associated with c-termini-transaction domain of β-catenin. Tripterygium wilfordii Hook F., which contains triptonide, has been traditionally used in clinic in China, suggesting that triptonide may have ideal drug properties. Our discovery of triptonide as an effective Wnt inhibitor may represent an important step in identification of bioactive small molecule drugs to stimulate endogenous cardiac progenitor cells for cardiac repair.