GDF15 and obesity due to melanocortin 4 receptor deficiency: To investigate the contribution of GDF15 to the anti-obesity effect of artesunate, we used an adeno-associated virus (AAV8) expressing Gdf15-specific shRNA (shGDF15) to knock down GDF15 in the liver and kidney, from which artesunate-induced GDF15 is mainly derived (Fig S9A, B).