Abstract
The microbiome and its components on the skin and in the environment contribute to the maintenance of skin homeostasis. Here, we examined the effect of the continuous application of lipopolysaccharide (LPS), a gram-negative bacterial component, on skin sensitivity and water retention on the facial skin of 11 human subjects. To analyze the mechanism of this effect, we used the human keratinocyte cell line HaCaT to examine whether selected genes related to barrier function or tight junctions change upon LPS stimulation in vitro. Lactic acid sting tests of 11 subjects with sensitive skin showed that the use of a lotion containing LPS derived from Pantoea vagans (LPSpv) relieved the sensation of skin irritation. Additionally, stratum corneum hydration increased, and transepidermal water loss decreased in these test subjects. In HaCaT cells, stimulation of 1 μg/mL LPSpv promoted cell proliferation. RT-qPCR revealed that stimulation of 100 ng/mL LPSpv significantly increased the gene expression of filaggrin and fibronectin, which are related to barrier function, and of claudin 1, related to tight junctions. Collectively, these results suggest that LPSpv enhances epidermal barrier function.
