Inhibition of smoothened receptor by vismodegib leads to micrognathia during embryogenesis

The mandible is an important part of the craniofacial skeleton. Mandibular development is complex and involves multiple signaling pathways. These signaling pathways participate in a complex regulatory mechanism to regulate mandibular growth. The function of hedgehog signaling has previously been shown to be crucial for mandibular arch development. We treated pregnant ICR mice with the hedgehog pathway inhibitor vismodegib by oral gavage to establish a micrognathia model, which was mandible development defective. Compared to control, this model exhibited reduced mesenchymal cell proliferation and increased apoptosis. The development of the Meckel's cartilage and the condensations of mesenchymal cells were delayed by approximately one day in treated embryos. These results reveal that Smoothened may have shaped the mandible during mandibular growth by ensuring cell survival, proliferation, and development of Merkel's cartilage.