Open AccessEucalyptus Citriodora Extract Regulates Cutaneous Homeostasis Including Immune Dysregulation and Skin Barrier Dysfunction Via the Modulation of Peroxisome Proliferator-Activated Receptor-β/δ (PPAR-β/δ) Pathway
Author(s) -
Takuhiro Yamada,
Akihiro Aioi
Publication year - 2020
Publication title -
trends in immunotherapy
Language(s) - English
Resource type - Journals
ISSN - 2573-5985
DOI - 10.24294/ti.v4.i2.1130
Subject(s) - hacat , peroxisome proliferator activated receptor , downregulation and upregulation , keratinocyte , microbiology and biotechnology , transfection , receptor , biology , inflammation , cytokine , chemistry , endocrinology , medicine , cell culture , immunology , biochemistry , genetics , gene
Perturbation of cutaneous homeostasis including immune dysregulation and skin barrier dysfunction evokes skin disorders. In this study, we examined the effect of Eucalyptus citriodora (Euc-c) extract on cytokine production, cell proliferation and cell differentiation in HaCaT cells to elucidate its influence on cutaneous homeostasis. Euc-c suppressed significantly LPS-induced IL-6 and TNF-a-induced IL-8 production from HaCaT cells. Conversely IL-1ra production was significantly enhanced by Euc-c. The expressions of IVL, CERS3 and CERS4, keratinocyte differentiation markers, were upregulated to 3.1, 2.8 and 2.7-fold respectively by Euc-c treatment, compared to the control, while the proliferation was downregulated. The lipid contents in Euc-c-treated cells tended to increase, compared with non-treated cells. To explore the underlying mechanism of these effect, we next performed siRNA experiments against PPAR-b/d. Euc-c enhanced PPAR-b/d mRNA expression to 3.25-fold, while PPAR-b/d mRNA expression in transfected cells was suppressed. The expressions of IVL, CERS3 and CERS4 in transfected cells were suppressed to 1.48, 0.82 and 0.72-fold respectively, concomitant with suppression of PPAR-b/d mRNA expression. These results indicated that Euc-c exerts anti-inflammatory effects and regulates keratinocyte differentiation via the modulation of PPAR-b/d pathway. Therefore, the application of Euc-c is expected to exert beneficial effect on skin disorders evoked by perturbation of skin homeostasis.