Plantaricin A promotes the cellular antioxidant defenses of human keratinocytes and modulates the synthesis of filaggrin, involucrin, beta-defensin 2, and tumor necrosis factor alpha
De Angelis M
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Plantaricin A (PlnA) is an amphiphilic α-helical bacteriocin-like pheromone which exerts antimicrobial and pheromone activities through different mechanisms. Plna was synthesized chemically and used as a pure peptide or synthesized biologically using Lactobacillus plantarum DC400 co-cultured with Lactobacillus sanfranciscensis DPPMA174. Cell-free supernatant (CFS) was used as a crude PlnA preparation. As estimated using the 3-(4,5-dimethyl-2-yl)-2,5-diphenyltetrazolium bromide and the 2′,7′–dichlorofluorescein diacetate assays, both PlnA preparations increased the antioxidant defenses of human NCTC 2544 keratinocytes. PlnA (10 μg/mL) had a higher activity than hyaluronic acid or 125 μg/mL α–tocopherol. Effects on the transcriptional regulation of filaggrin (FLG), involucrin (IVL), hyaluronan synthase (HAS2), human β-defensin-2 (HBD-2), and tumor necrosis factor-alpha (TNF-α) genes were assayed. Compared with the control, expression of the FLG gene in NCTC 2544 cells increased in cells treated with hyaluronic acid, 1, or 10 μg/mL PlnA. Compared with the control, the level of IVL gene expression increased in NCTC 2544 cells treated with 10 μg/mL PlnA. No significant difference was found between the level of the HAS2 gene expressed by control cells and cells treated with PlnA. Compared with chemically synthesized PlnA, the up–regulation of the HBD-2 gene by CFS was higher. Compared with the control, expression of TNF-α decreased in NCTC 2544 cells after treatment with 1 or 10 μg/mL of chemically synthesized PlnA. In contrast, the level of TNF-α was highest in the presence of 10 μg/mL CFS PlnA. The findings of this study suggest that the PlnA was positively sensed by human keratinocytes, promoting antioxidant defenses, barrier functions and antimicrobial activity of the skin.