A peptide probe for targeted brown adipose tissue imaging

The presence of brown adipose tissue (BAT) responsible for thermogenic energy dissipation has been revealed in adult humans and has high clinical importance. Due to limitations of current methods for BAT detection, analyzing the abundance and localization of BAT in the body has remained challenging. Here, we screen a combinatorial peptide library in mice and characterize a peptide (with the sequence CPATAERPC) that selectively binds to the vascular endothelium of BAT, but not of intraperitoneal white adipose tissue (WAT). We show that in addition to BAT, this peptide probe also recognizes the vasculature of BAT-like depots of subcutaneous WAT. Our results indicate that the CPATAERPC peptide localizes to BAT even in the absence of sympathetic nervous system stimulation. Finally, we demonstrate that this probe can be used to identify BAT depots in mice by whole body near-infrared (NIR) fluorescence imaging.