Lipids are indispensable for energy storage, membrane structure and cell signalling. However, dynamic changes in various categories of endogenous lipids in mammalian early embryonic development have not been systematically characterized. Here we comprehensively investigated the dynamic lipid landscape during mouse and human early embryo development. Lipid signatures of different developmental stages are distinct, particularly for the phospholipid classes. We highlight that the high degree of phospholipid unsaturation is a conserved feature as embryos develop to the blastocyst stage. Moreover, we show that lipid desaturases such as SCD1 are required for in vitro blastocyst development and blastocyst implantation. One of the mechanisms is through the regulation of unsaturated fatty-acid-mediated fluidity of the plasma membrane and apical proteins and the establishment of apical–basal polarity during development of the eight-cell embryo to the blastocyst. Overall, our study provides an invaluable resource about the remodelling of the endogenous lipidome in mammalian preimplantation embryo development and mechanistic insights into the regulation of embryogenesis and implantation by lipid unsaturation.

脂质对于能量储存、膜结构和细胞信号传导是不可或缺的。然而，哺乳动物早期胚胎发育中各类内源脂质的动态变化尚未得到系统的表征。在这里，我们全面研究了小鼠和人类早期胚胎发育过程中的动态脂质景观。不同发育阶段的脂质特征是不同的，特别是对于磷脂类别。我们强调，高度的磷脂不饱和度是胚胎发育到囊胚阶段的一个保守特征。此外，我们发现脂质去饱和酶（如 SCD1）是体外囊胚发育和囊胚植入所必需的。其中一种机制是通过调节不饱和脂肪酸介导的质膜和顶端蛋白的流动性以及在八细胞胚胎发育至囊胚过程中建立顶端-基底极性。总的来说，我们的研究为哺乳动物植入前胚胎发育中内源脂质组的重塑以及脂质不饱和调节胚胎发生和植入的机制见解提供了宝贵的资源。