Study reveals how retinoic acid regulates brood sac formation and pregnancy of male seahorses

Seahorses have the unique feature of male pregnancy, which includes carrying many embryos in a brood sac that incubates and feeds the embryos, similar to the mammalian placenta. However, the regulatory networks underlying brood sac formation and pregnancy remain largely unknown.

Recently, researchers led by Prof. Lin Qiang of the South China Sea Institute of Oceanology (SCSIO) of the Chinese Academy of Sciences found that retinoic acid (RA) synthesis and signaling pathway played an essential role in education. of the brood pouch and in pregnancy in seahorses. This work was published in The innovation on October 13.

Researchers in Lin’s group previously showed that seahorses had the highest evolutionary rate among the Syngnathidae family, and the syngnathid fish shared convergent genomic changes with placental mammals.

In this study, they further focused on the specific structure of the brood sac in male seahorses and combined transcriptomic and metabolomic analyzes to reveal the regulatory mechanism underlying pouch development.

RA may function upstream of testosterone and progesterone, thus directly affecting the formation of brood sacs by regulating the expression of fshr and cyp7a1. Furthermore, AR could influence tissue remodeling, organ development and immune defense by regulating target genes.

Furthermore, the substantial decrease in RA and some antioxidant substances could regulate antioxidant defense during pregnancy, essential for the success of gestation in seahorses.