Fig. 2.

Molecular mechanisms and signal pathways of syncytin-1 expression in preeclampsia (PE) Induction of DNA methylation by the DNA methyltransferases DNMT1 and DNMT3B can reduce syncytin-1 expression. Human chorionic gonadotrophin (hCG) could regulate syncytin-1 expression by activating cAMP-PKA-GCM1 signal pathway. PPARγ and RXRα can form heterodimers, and their activation allows muscle-invasive bladder cancer to evade immune surveillance. PPARγ/RXRα nuclear hormone receptor activators such as 9-cis retinoic acid and forskolin can also reduce the expression of syncytin-1 and promote the fusion of villous cytotrophoblast into syncytiotrophoblast. T-cell death-associated gene 51 (TDAG51) is a potential inhibitor of PPARγ/RXRα