Figure 2A shows the flow cytometry gating strategy to identify ATMs in young and old mice of both sexes. Initially, we performed immunofluorescence studies of ATMs in GWAT that showed obesity in older male GWAT led to the appearance of CLSs depicted by mac-2 staining for macrophages and cav-1 for adipocytes (Figure 2B; top). CLS were also depicted by H&E staining (Figure 2B; bottom) to be numerous and clustered closer together in males compared to females. This evidence concerns the gene CAV1 and obesity due to melanocortin 4 receptor deficiency.