In recent years, literature shows that proteases have the potential to induce inflammation through activation of protease-activated receptors (PAR) [1]. Besides secondary plant constituents like phenols, di-, and polyterpenes, proteases are abundant in latices from plants of Euphorbiaceae Juss. [2,3]. It is known, that these latices induce strong skin inflammation. Therefore, we investigated the plant latex from Euphorbia mauritanica L. (Euphorbiaceae). Human skin is the first barrier of the body in defense from environmental influences and the inflammatory response is an important tool against pathogens. In the current study, we focused on the inflammatory potential of the combination of diterpenes with proteases on a human skin model.
Mauritanicain, a serine protease from E. mauritanica, was isolated by ion exchange and size exclusion chromatography. The human skin model was composed by primary keratinocytes and fibroblasts. Mauritanicain (10 µg/mL) and PMA (10 ng/mL) were incubated for one hour on the skin model. 48 hours after removing the stimulating substances, medium was removed and investigated by FACS and ELISA. When the experiment was finished, HE-staining of the skin model was performed. The occurrence of PAR2 was visualized by immunofluorescence staining.
The results showed an increased IL-1ß release by single treatment with Mauritanicain (2-fold) and by the combination of Mauritanicain and PMA (1.5-fold). The results indicate that there is no synergism between Mauritanicain and PMA.
[1] Guenther F, Melzig MF. Protease-activated receptors and their biological role - focused on skin inflammation.; J Pharm Pharmacol 2015; 67: 1623-1633
[2] Sytwala S, Guenther F, Melzig MF. Lysozyme- and chitinase activity in latex bearing plants of genus Euphorbia – A contribution to plant defense mechanism. Plant Physiology and Biochemistry 2015; 95: 35-40
[3] Vasas A, Hohmann J. Euphorbia diterpenes: isolation, structure, biological activity, and synthesis (2008-2012). Chem Rev 2014; 114: 8579-8612