Critical roles of glycolysis in epidermal barrier disruption under mechanical stress in the skin

Summary: Abstract Body: The skin, as the outermost organ, is constantly exposed to environmental stimuli, including mechanical stress. While repeated mechanical stress, such as scratching, is known to disrupt the epidermal barrier and lead to inflammation, the mechanisms underlying barrier disruption caused by faint mechanical stress remain unclear. Here, we demonstrate that repeated faint mechanical stress activates the glycolysis pathway in epidermal keratinocytes, playing a critical role in epidermal barrier disruption. Using a tape-stripping model, we found that repeated faint mechanical stress caused significant barrier disruption, as assessed by transepidermal water loss and dye-penetration assays, without triggering notable inflammation. Bulk RNA sequencing of the epidermis revealed an upregulation of metabolic pathways, including glycolysis-related processes, and immunohistochemical analysis confirmed increased expression of Glut1, the primary glucose transporter in keratinocytes. Pharmacological inhibition of Glut1 nearly completely prevented barrier disruption caused by tape stripping. Furthermore, RNA sequencing revealed that inhibition of glycolysis enhanced the expression of barrier-related genes, including Flg and Lor, in the epidermis of tape-stripped skin. Similar findings were observed in normal human epidermal keratinocytes, where glycolysis inhibition increased the expression of these genes and their protein products. These findings highlight the pivotal role of glycolysis in mediating epidermal barrier disruption induced by faint mechanical stress. Interrupting this cycle may offer a novel therapeutic strategy to prevent epidermal barrier disruption as well as subsequent skin inflammation caused by repeated mild mechanical stress. Atsuko Funakoshi¹, Tetsuya Honda¹ 1. Dermatology, Hamamatsu Ika Daigaku, Hamamatsu, Shizuoka Prefecture, Japan. Epidermal Structure and Barrier Function