Adipocyte heterogeneity underlying adipose tissue functions

Adipose tissue distribution in the human body is highly heterogeneous, and the relative mass of different depots is differentially associated with metabolic disease risk. Distinct functions of adipose depots are mediated by their content of specialized adipocyte subtypes, best exemplified by thermogenic adipocytes found in specific depots. Single-cell transcriptome profiling has been used to define the cellular composition of many tissues and organs, but the large size, buoyancy and fragility of adipocytes have rendered it challenging to apply these techniques to understand the full complexity of adipocyte subtypes in different depots. Discussed here are strategies that have been recently developed for investigating adipocyte heterogeneity, including single-cell RNASeq profiling of the stromal vascular fraction to identify diverse adipocyte progenitors, and single-nuclei profiling to characterize mature adipocytes. These efforts are yielding a more complete characterization of adipocyte subtypes in different depots, insights into the mechanisms of their development, and perturbations associated with different physiological states such as obesity. A better understanding of the adipocyte subtypes that compose different depots will help explain metabolic disease phenotypes associated with adipose tissue distribution and suggest new strategies for improving metabolic health.