Human adipose tissue-derived mesenchymal stem cells have been shown to secrete exosomes carrying functionally active NEP (Katsuda et al., 2013) and neuronally differentiated human umbilical cord mesenchymal stem cells transplanted into APP transgenic mice reduced Aβ levels and enhanced both NEP and IDE levels, as well as cognitive function, raising the prospect of future cell therapy for AD (Yang et al., 2013). The gene discussed is APP; the disease is Alzheimer disease.