The Role of Microbial Metabolites in the Response of the Epidermal Barrier to Ultraviolet Radiation

The epidermis of skin is an essential barrier without which, humans would not be able to live as terrestrial organisms. The skin barrier prevents both excessive loss of water from within the body, and ingress of potential toxic agents from the environment. Epidermal barrier function is conferred by the outermost layer of the skin, the stratum corneum, and also by tight junctions between keratinocytes in the granular layer of the epidermis.

However, it is now becoming clear that the microbiota of the skin is also crucial to epidermal barrier function. Arguably, the greatest environmental challenge to the skin barrier is exposure to ultraviolet radiation (UVR) from ambient sunlight. In humans, high dose UVR compromises skin barrier with increased transepidermal water loss being observed (5).

Chronic exposure to UVR is also known to result in changes to tight junction structure and protein expression (6,7). Although many of these changes are driven by the skin itself, we hypothesise that some may be due to: loss of bacteria which produce metabolites essential for the barrier or changes to the metabolite profile produced by bacteria in response to UVR

This project seeks to investigate the effects of microbial metabolites in the response of the epidermal barrier to UVR.