Lipidomic Remodeling during Lipid-Rich Mammalian Oocyte Maturation and Early Embryo Development

<title>Abstract</title> <p>Many wild mammals (such as American mink, Roe deer, Finless porpoises) accumulate high amounts of lipids during oocyte growth, and these lipids often negatively affect the success of oocyte and embryo cryopreservation, a key assisted reproductive technology used to establish biobanks for endangered mammals. Although a recent study has mapped the lipidomic landscape of lipid-poor mouse and human embryos, the lipid profile in mammals with lipid-rich oocytes and embryos remains largely unexplored. Here, applying pigs as the lipid-rich model, we comprehensively characterized lipid remodeling during porcine oocyte maturation and early embryo development. By integrating transcriptome and translatome sequencing (T&amp;T-seq) data, we demonstrated that triglyceride (TG) lipolysis and phosphatidylinositol (PI) synthesis specifically contribute to porcine oocyte maturation. Moreover, phosphatidic acid (PA) regulates cell polarity and lineage specification through histone acetylation establishment, thereby promoting blastocyst formation. Notably, we found that hormone-sensitive lipase (HSL) specifically drives TG lipolysis in porcine early embryos, and moderate HSL overexpression remarkably enhanced the survival rates of cryopreserved blastocysts. These findings provide a novel strategy for the cryopreservation of livestock and endangered mammals with lipid-rich embryos.</p>