Developmental transition of brown adipose tissue from a thermogenic to a lipogenic phenotype in neonatal goats revealed by single-nucleus transcriptomics

Brown adipose tissue (BAT) is essential for neonatal thermogenesis and early-life metabolic adaptation. In goat neonates, BAT is primarily concentrated in the perirenal region and rapidly regresses during the first month after birth, yet the cellular and molecular programs driving this transition remain poorly defined. In the present study, a comprehensive single-nucleus transcriptomic atlas of perirenal adipose tissue was generated from 54 638 high-quality nuclei collected at postnatal days 0, 7, and 14. This resource resolved six transcriptionally distinct perirenal adipose cell populations and revealed pronounced developmental remodeling after birth. Adipocyte progenitors exhibited strong secretory signatures, indicating potential involvement of secretory programs in early postnatal adipose remodeling. Across early postnatal development, perirenal adipose tissue showed coordinated transcriptional remodeling in lipid and fatty acid metabolism, accompanied by marked changes in AMPK and PPAR signaling, indicating a progressive shift from a thermogenesis-associated program toward lipid storage. This transition was accompanied by expansion of adipocyte subpopulations associated with fat deposition and reduction of populations linked to thermogenic function. By postnatal day 14, perirenal adipose tissue had undergone a marked transition from a brown adipose phenotype toward a white-like adipose state. These findings provide insights into the early postnatal cellular trajectory of goat BAT and its role in neonatal thermogenesis and adipose tissue remodeling.