Understanding adipocyte heterogeneity across species, depot, and disease

Adipose tissue is a key regulator of metabolic homeostasis; however, its dysfunction can lead to complications, including the development of metabolic disease. While mature adipocytes play an important role in this relationship, their size and buoyancy have made characterizing them difficult at the single cell level. Development of single-nuclear RNA sequencing and spatial transcriptomics have allowed for the study of mature adipocytes at unprecedented resolution and have enabled the identification of previously unappreciated subpopulations of adipocytes, some of which are associated with specific adipose depots or metabolic conditions. Here, we review the recent publications in the field and attempt to synthesize the populations identified by individual studies into classes based on their predicted functionality. We also discuss critical gaps in our current understanding of adipocyte subpopulations, including the current dearth of functional characterization of these populations.