Ergothioneine induces Upregulated Expression of Beta-Defensins in Keratinocyte

Objective: Human beta-defensins (hBDs) are innate antimicrobial peptides produced in keratinocytes, which play important role in the protective barrier of oral epithelium. Ergothioneine (EGT) is a natural compound, synthesized by actinobacteria, fungi and mushroom and exhibits antioxidant functions in many cell models. The present study investigated effect of EGT on the expression patterns of hBD-1, 2 and -3 in keratinocyte. Methods: EGT was purified from Japanese Tamogitake mushroom that have a highest EDT content among mushrooms. HaCaT cells, a human keratinocyte cell line, were grown in DMEM supplemented with 10% fetal bovine serum. The cells were incubated with EGT at the concentration of 0 (control), 0.1, 1, 5mM for 2 or 24 hours. Expression levels of the hBDs mRNAs were evaluated by RT-PCR and quantitative RT-PCR using TaqMan probes. In order to elucidate the intracellular pathway involved in the expression of hBDs, cells were pretreated with inhibitors [AG1478 (EGFR), SB203580 (p38MAPK), or JNKII (JNK)] for an hour in some experiments. The significance of differences was analyzed by Student's t-test (n=5). Results: EGT induced upregulated expression of hBD-1 and -3 in dose- and time-dependent manners. The expression levels of hBD-1 and -3 were significantly higher in keratinocytes incubated with 5nM of EDT for 2hrs than in control. These expression levels were significantly higher in the cells incubated with 0.1mM of EDT for 24hrs than in control. The JNK II inhibitor abolished the upregulated expression of hBD-3 induced by the stimulation with EGT. Conclusion: These results suggest that Ergothioneine induces upregulated expression of hBD-1 and -3 in the keratinocyte, and is possibly involved in MAPK pathway.