UV-Induced DNA Methyltransferase 1 Promotes Hypermethylation of Tissue Inhibitor of Metalloproteinase 2 in the Human Skin

Ultraviolet (UV) radiation is a major risk factor for the induction of skin aging [1]. Prolonged UV exposure accelerates the process of aging by degrading the structural integrity of the dermal extracellular matrix (ECM), resulting in the wrinkled appearance of the skin. The disintegration of each dermal ECM protein is implemented by a large number of proteinases known as matrix metalloproteinases (MMPs). In photoaged skin, an overproduction of MMPs such as MMP1 (interstitial collagenase), MMP3 (stormelysin-1), and MMP9 (gelatinase) and an insufficient amount of collagen synthesis were observed [2–4].