Single-cell multi-omics reveals multiple adipogenic pathways and diverse multilineage specializations during embryonic fat tail morphogenesis

Embryonic adipogenesis remains one of the least understood aspects of adipose biology in mammals due to time sensitivity, limited tissue volume, and ethical concerns. Here, we uniquely applied single-cell multi-omics sequencing to the developing adipose tissues of a representative mammalian species, characterized by genetically determined, significant fat deposition in the tail during embryogenesis, with a specific focus on adipogenic patterns and crucial regulatory factors. Our dataset spans all stages of adipogenesis (E50 to E80), revealing three major cellular origins of fat deposition: progenitor and stem cells, connective tissue progenitors, and vascular smooth muscle cells. By integrating scRNA-seq, scATAC-seq, and functional validation, we identified key enhancer-driven gene regulatory networks (eGRNs) governing adipogenesis, with DBI emerging as a critical regulator through its interaction with PPARG. Additionally, we delineated developmental trajectories and unique eGRNs underlying angiogenesis, osteogenesis, chondrogenesis, and myogenesis associated with fat formation. Our findings provide novel insights into embryonic adipogenesis in mammals and reveal critical regulons governing lineage specialization.

由于存在时间敏感性、组织样本量有限及伦理争议等问题，哺乳动物胚胎脂肪生成仍是脂肪生物学领域中认知最为薄弱的方向之一。本研究首次将单细胞多组学测序技术应用于一种典型哺乳动物的发育中脂肪组织——该物种在胚胎发育阶段的尾部存在遗传决定的显著脂肪沉积——并重点聚焦脂肪生成模式与关键调控因子。本数据集覆盖了胚胎脂肪生成的全部阶段（E50至E80），揭示了脂肪沉积的三大主要细胞起源：祖细胞与干细胞、结缔组织祖细胞以及血管平滑肌细胞。通过整合单细胞RNA测序（single-cell RNA sequencing, scRNA-seq）、单细胞转座酶可及性测序（single-cell assay for transposase-accessible chromatin using sequencing, scATAC-seq）及功能验证实验，我们鉴定出了调控胚胎脂肪生成的关键增强子驱动基因调控网络（enhancer-driven gene regulatory networks, eGRNs），并发现DBI通过与过氧化物酶体增殖物激活受体γ（PPARG）相互作用，成为重要的调控因子。此外，我们还阐明了与脂肪形成相关的血管生成、成骨、成软骨及成肌过程的发育轨迹及其独特的eGRNs调控机制。本研究结果为哺乳动物胚胎脂肪生成提供了全新的认知视角，并揭示了调控细胞谱系特化的关键调控子。