Expression of the Human Cathepsin L Inhibitor Hurpin in Mice: Skin Alterations and Increased Carcinogenesis

The study investigated the effects of expressing the human Cathepsin L inhibitor, hurpin, in transgenic mice. Hurpin, a serine protease inhibitor, was overexpressed in psoriatic skin and provided keratinocytes with increased resistance to UVB-induced apoptosis. Transgenic mice expressing human hurpin exhibited abnormal abdominal fur and a reduced number of apoptotic and caspase-3 positive cells after UV irradiation compared to wild-type mice. However, these mice showed increased susceptibility to skin cancer following chemical carcinogenesis. Gene expression analysis revealed differences related to antigen presentation and angiogenesis between wild-type and hurpin-transgenic mice. The findings suggested that Cathepsin L regulation by hurpin played a significant role in skin health and disease, potentially impacting human skin conditions.