Antioxidant properties of small proline-rich proteins : from epidermal cornification to global ROS detoxification and wound healing

Abstract

The small proline-rich (SPRR) proteins are generally known for their involvement in the formation and adaptation of the skin__s barrier. During the cornification process, they are cross-linked within the cornified cell envelope (CE) and as such they are responsible for the physical and permeability barrier function of our skin. In this thesis, the novel antioxidant properties of the SPRR proteins are described. As part of the CE, these proteins provide a natural antioxidant shield to our skin and act as our first line of defence against reactive oxygen species (ROS). Also during wound healing, SPRR proteins can directly reduce toxic ROS levels. This activity is directly related to their ability to promote cell migration and is essential in order to allow wound closure. A literature-based meta-analysis revealed their up-regulation in various forms of tissue injury, ranging from heart infarction and commensal-induced gut responses to nerve regeneration and burn injury. Apparently, SPRR proteins have a far more widespread role in wound healing and tissue remodelling than their established function in skin cornification. Likely, SPRR proteins provide all tissues with an efficient, finely tuneable antioxidant barrier, specifically adapted to the tissue involved and the damage inflicted.