SLC7A5 and obesity due to melanocortin 4 receptor deficiency: To this end, we selectively reexpressed Slc7a5 in LepR-expressing neurons by stereotaxically and bilaterally microinjecting a Cre-inducible adeno-associated virus (AAV), AAV-hSynI-DIO-Slc7a5-mCherry (AAV-Slc7a5), into the VMH of LepR-Cre Slc7a5fl/fl mice before the onset of obesity (Figure 7A).