Elafin

Elafin, also known as skin-derived antileukoproteinase (SKALP), is a small (11.7 kDa) serine protease inhibitor belonging to the Trappin family. It is encoded by the PI3 gene in humans. Elafin is primarily expressed in epithelial cells, especially in the skin, lungs, and cervix.

Elafin plays a crucial role in regulating inflammation and tissue homeostasis. It functions by inhibiting serine proteases, including neutrophil elastase, proteinase 3, and matrix metalloproteinases (MMPs). These proteases are involved in the breakdown of the extracellular matrix and the activation of inflammatory pathways. By inhibiting these enzymes, Elafin helps to prevent excessive tissue damage and inflammation.

Elafin expression is often upregulated in response to inflammatory stimuli, such as bacterial infections, cytokines, and mechanical stress. Its increased expression is thought to be a protective mechanism to limit the destructive effects of inflammatory responses.

Dysregulation of Elafin expression has been implicated in various diseases, including psoriasis, chronic obstructive pulmonary disease (COPD), cystic fibrosis, and certain cancers. Reduced Elafin expression may contribute to uncontrolled inflammation and tissue degradation, whereas increased Elafin expression may contribute to tumor growth and metastasis in some contexts.

Elafin is often studied as a potential therapeutic target for inflammatory diseases and certain cancers due to its ability to modulate protease activity and inflammation.