Parasitic Flatworms Contain Substances that Induce Sexuality in Planarians—A Clue for Drug Discovery Aimed at Eradicating Trematodiasis, a "Neglected Tropical Disease"

We have revealed that sexualizing factors, which can induce planarians from an asexual to a sexual state, are also present in parasitic flatworms such as monogeneans (which mainly infect fish) and trematodes (which mainly infect humans and livestock).

Through metabolome and transcriptome analyses, we identified 18 types of ovary-inducing substances. Six of these were compounds related to purine metabolism, suggesting that purine metabolism is important for the sexualization mechanism.

The fact that sexualizing factors known in planarians are widely conserved even in parasitic flatworms strongly suggests that their downstream mechanisms may also be conserved in the sexual maturation of monogeneans and trematodes. In the future, if research on elucidating the molecular mechanisms of sexual maturation and drug discovery, starting with these sexualizing factors and using safe planarians as a platform, progresses, it is expected to lead to a reduction in the health damage and economic losses caused by monogeneans and trematodes.