The expanding problem of adipose depot remodeling and postnatal adipocyte progenitor recruitment

•De novo adipocyte differentiation occurs in various postnatal physiological settings.•Recent studies reveal precursors for white, brown, and beige adipocytes in adult mice.•Committed preadipocytes reside in the adipose tissue vasculature as mural cells.•Adipose precursors are regulated in obesity in a sex and depot-dependent manner.•The exact requirement of recently identified precursor populations remains unclear.

The rising incidence of obesity and associated metabolic diseases has increased the urgency in understanding all aspects of adipose tissue biology. This includes the function of adipocytes, how adipose tissue expands in obesity, and how expanded adipose tissues in adults can impact physiology. Here, we highlight the growing appreciation for the importance of de novo adipocyte differentiation to adipose tissue expansion in adult humans and animals. We detail recent efforts to identify adipose precursor populations that contribute to the physiological postnatal recruitment of white, brown, and beige adipocytes in mice, and summarize new data that reveal the complexity of adipose tissue development in vivo.