Coincidently, it is reported that APN can regulate the activation of autophagy in vivo and in vitro, and APN exerts as a novel therapeutic target of diabetic retinopathy through inhibiting autophagy [47]; however, APN exhibits a protective role against Alzheimer-like pathologies via triggering autophagy [48], emphasizing a dual relationship between APN and autophagy in different diseases. Here, ANPEP is linked to diabetic retinopathy.