The Detrimental Effects of Aberrant Regulation on the Hedgehog Signaling Pathway

Abstract

The Hedgehog (Hh) signaling pathway is a conserved neural pathway that plays an important role in the embryonic development of both invertebrates and vertebrates. This pathway was originally discovered in the species Drosophila melanogaster, the common fruit fly, and is found among a variety of species. The signal transmission from cell membranes are regulated by the Hh signaling pathway and dictate embryonic development. There are three main Hedgehog ligand proteins that regulate the transcription of target genes for this pathway. The three types of Hedgehog in the mammalian body are Sonic Hedgehog (Shh), important in the specification of cells in the nervous system, Desert Hedgehog (Dhh) which is seen in the hormoneproducing gonad glands involved in reproduction, and Indian Hedgehog (Ihh) which plays a role in skeletal development (Carballo et al., 2018). All of the components in the Hh pathway are found in the primary cilium, which is an immobile organelle that juts out from the side of a cell and can sense the surrounding environment (Gigante & Caspary, 2020). When the pathway is regulated, typical development can occur. However, the dysregulation of the Hh signaling pathway may lead to a variety of diseases and disorders, including tumorigenesis of medulloblastoma, the most common malignant brain tumor.