Per- and Polyfluoroalkyl Substances Disrupt Mouse Embryo Compaction by Targeting c-MYC

Epidemiological studies link per- and polyfluoroalkyl substances (PFAS) to reduced preimplantation embryo quality, yet experimental evidence and mechanistic insights remain limited. Compaction is a pivotal event in the morula stage of preimplantation development. This study established a phenotypic screening platform using circularity of morula-like aggregates derived from mouse expanded pluripotent stem cells to screen PFAS that may disrupt compaction. Among the 19 tested PFAS, five were identified to be positive hits, and perfluorooctanoic acid (PFOA) showed the most pronounced effect. PFOA inhibited the expression of adhesion molecules and disrupted the cell polarity in morula-like aggregates at 100 nM, and it reduced the proportion of high-quality aggregates at 10 nM. Similar effects were observed in mouse embryos. Mechanistically, PFOA interfered with c-MYC/MAX complex formation with a half-maximal inhibitory concentration of 22.3 μM, and inhibited its transcriptional activity with the lowest effective concentration of 40 μM, comparable to that of the commercial inhibitor 10074-G5. c-MYC overexpression rescued PFOA-induced damage in morula-like aggregates. The c-MYC inhibitor 10074-G5 impaired cell adhesion and polarization in both morula-like aggregates at 1000 nM and mouse embryos at 5 μM. Our study reveals that PFAS can disrupt embryo compaction via inhibiting the c-MYC, which may contribute to the reduced preimplantation embryo quality.