Rapamycin treatment causes developmental delay, pigmentation defects, and gastrointestinal malformation on Xenopus embryogenesis

Rapamycin is a drug working as an inhibitor of the TOR (target of rapamycin) signaling pathway and influences various life phenomena such as cell growth, proliferation, and life span extension in eukaryote. However, the extent to which rapamycin controls early developmental events of amphibians remains to be understood. Here we report an examination of rapamycin effects during Xenopus early development, followed by a confirmation of suppression of TOR downstream kinase S6K by rapamycin treatment. First, we found that developmental speed was declined in dose-dependent manner of rapamycin. Second, black pigment spots located at dorsal and lateral skin in tadpoles were reduced by rapamycin treatment. Moreover, in tadpole stages severe gastrointestinal malformations were observed in rapamycin-treated embryos. Taken together with these results, we conclude that treatment of the drug rapamycin causes enormous influences on early developmental period.

Research highlights
► Does famous anti-aging drug rapamycin work from the beginning of life? The answer is yes.
► This study shows that developmental speed of frog embryo was dose-dependently decreased by rapamycin treatment.
► In additions, morphogenetic effects such as less pigmentations and gut malformation are occurred by rapamycin.