Cathepsin D contributes to the accumulation of advanced glycation end products during photoaging

Advanced glycation end products (AGEs) are the final products of nonenzymatic glycation of reducing sugars and reactive aldehydes with proteins, lipids and nucleic acids [1]. As AGEs alter the structure and function of proteins, they contribute to the pathogenesis of many diseases, especially diabetes and aging [2]. Skin is the largest organ of human body, and one typical feature of its aging is the accumulation of AGEs [3]. Glycation-associated skin autofluorescence has been found to be correlated with chronological aging in a large number of healthy subjects [4,5].