Signaling through RXRβ and its agonist, bexarotene, promotes neuron formation in Xenopus laevis embryos

Bexarotene, characterised as a pan-RXR agonist, reduces the symptoms of Alzheimer’s disease (AD) in mouse models by clearing amyloid plaque and by promoting neurogenesis. In this paper, we show that RXR-initiated bexarotene signaling generates additional neurons both during normal Xenopus laevis development and in ectodermal explants in which BMP- signaling is inhibited.

Differential gene expression between ectodermal explants taken from uninjected and embryos co-injected with mRNA that expresses Noggin, a BMP antagonist, and RXRβ identifies genes mediating change from an epidermal to a neural fate. The explants express genes associated with an anterior neural, but not neuronal fate. The addition of bexarotene to equivalent co-injected explants activates genes that promote neuronal differentiation and posterior character, including genes of the canonical Wnt signaling pathway.