Extracellular DAMPs in Plants and Mammals: Immunity, Tissue Damage and Repair

Innate immune receptors, well known mediators of response to non-self-molecules and inflammation, also act as mediators of immunity triggered by ‘damage-associated molecular patterns’ (DAMPs). Pathogen-associated molecular patterns (PAMPs) cause inflammation in mammals and a rapid immune response in plants, while DAMPs trigger more complex responses, including immunity, tissue maintenance and repair. DAMPs, their receptors and downstream transduction mechanisms are often conserved within a kingdom or, due to convergent evolution, are similar across the kingdoms of life. Herein, we describe the dynamics and functionality of specific extracellular DAMP classes and their receptors in immunity, inflammation and repair of tissue damage in plants and mammals. Vertebrates and plants harbor an innate-type immune system that shows striking similarities. Structural similarities and conservation seem to characterize DAMP signaling across the evolutionary tree. Animals and plants share remarkably similar regulatory mechanisms that involve the ECM; some of these might be mediated by evolutionarily conserved elements, whereas others might derive from convergent evolution.