SLC6A2 and obesity due to melanocortin 4 receptor deficiency: Unlike other adipose tissue macrophages and consistent with their location, sympathetic neuron-associated macrophages express two proteins involved in the import and the degradation of NE allowing its regulation in the extracellular space: the NE transporter SLC6A2 and the NE catalyzer monoamine oxidase A. However, they have shown that this macrophage population plays a major role in obesity because specific ablation of SLC6A2 in these macrophages induced weight loss and lipid mobilization.