Tracking adipogenesis during white adipose tissue development, expansion and regeneration

Qiong Wang and colleagues introduce the AdipoChaser mouse, an in vivo tool to track the formation and turnover of adipocytes. They use this inducible mature adipocyte lineage-tracing system to monitor adipogenesis and follow the formation of white and beige adipocytes under different conditions: high-fat diet, cold exposure and β-adrenergic stimulation. The system produced some interesting findings on in vivo adipogenesis, including that beige adipocytes differentiate de novo from specialized precursors rather than by transdifferentiation of mature white adipocytes. White adipose tissue displays high plasticity. We developed a system for the inducible, permanent labeling of mature adipocytes that we called the AdipoChaser mouse. We monitored adipogenesis during development, high-fat diet (HFD) feeding and cold exposure. During cold-induced 'browning' of subcutaneous fat, most 'beige' adipocytes stem from de novo–differentiated adipocytes. During HFD feeding, epididymal fat initiates adipogenesis after 4 weeks, whereas subcutaneous fat undergoes hypertrophy for a period of up to 12 weeks. Gonadal fat develops postnatally, whereas subcutaneous fat develops between embryonic days 14 and 18. Our results highlight the extensive differences in adipogenic potential in various fat depots.