Dieckol, a Component of Ecklonia cava, Suppresses the Production of MDC/CCL22 via Down-Regulating STAT1 Pathway in Interferon-gamma Stimulated HaCaT Human Keratinocytes

Macrophage-derived chemokine, C-C motif chemokine 22 (MDC/CCL22), is one of the inflammatory chemokines that controls the movement of monocytes, monocyte-derived dendritic cells, and natural killer cells. Serum and skin MDC/CCL22 levels are elevated in atopic dermatitis, which suggests that the chemokines produced from keratinocytes are responsible for attracting inflammatory lymphocytes to the skin. A major signaling pathway in the interferon-gamma (IFN-gamma)-stimulated inflammation response involves the signal transducers and activators of transcription 1 (STAT1). In the present study, we investigated the anti-inflammatory effect of dieckol and its possible action mechanisms in the category of skin inflammation including atopic dermatitis. Dieckol inhibited MDC/CCL22 production induced by IFN-gamma (10 ng/mL) in a dose dependent manner. Dieckol (5 and 10 muM) suppressed the phosphorylation and the nuclear translocation of STAT1. These results suggest that dieckol exhibits anti-inflammatory effect via the down-regulation of STAT1 activation.

The Chloroform Fraction of Carpinus tschonoskii Leaves Inhibits the Production of Inflammatory Mediators in HaCaT Keratinocytes and RAW264.7 Macrophages

Inflammation is the immune system's response to infection and injury-related disorders, and is related to pro-inflammatory factors (NO, PGE2, cytokines, etc.) produced by inflammatory cells. Atopic dermatitis (AD) is a representative inflammatory skin disease that is characterized by increasing serum levels of inflammatory chemokines, including macrophage-derived chemokine (MDC). Carpinus tschonoskii is a member of the genus Carpinus. We investigated the anti-inflammatory activity of C. tschonoskii by studying the effects of various solvent fractions prepared from its leaves on inflammatory mediators in HaCaT and RAW264.7 cells. We found that the chloroform fraction of C. tschonoskii inhibited MDC at both the protein and mRNA levels in HaCaT cells, acting via the inhibition of STAT1 in the IFN-gamma signaling pathway. In addition, the chloroform fraction significantly suppressed the expression of inflammatory factors induced by lipopolysaccharide stimulation, except COX-2 and TNF-alpha. These results suggest that the chloroform fraction of C. tschonoskii leaves may include a component with potential anti-inflammatory activity.