Structure and Immunomodulatory Activity of Microparticulate Mushroom Sclerotial ß-Glucan Prepared from Polyporus rhinocerus.

In this study, an immunologically active novel microparticulate mushroom ß-glucan (PRA-1p) was prepared using an alkali-soluble glucan PRA-1 by an emulsification and cross-linking method. PRA-1 was a hyperbranched (1→3),(1→6)-ß-d-glucan with a degree of branching of 0.89, isolated from the sclerotia of Polyporus rhinocerus. PRA-1 had a rod-like conformation, while PRA-1p exhibited a monodisperse and homogeneous spherical conformation with a diameter ranging from 0.3 to 2.0 µm in water. PRA-1p significantly induced nitric oxide and reactive oxygen species production as well as morphological changes of murine macrophages (RAW 264.7 cells) and upregulated their phagocytic activity. Furthermore, PRA-1p treatment markedly enhanced the secretion of cytokines, including cutaneous T cell-attracting chemokine 27, granulocyte-colony-stimulating factor, monocyte chemoattractant protein 1, macrophage inflammatory protein 1α, macrophage inflammatory protein 2, regulated on activation, normal T cell expressed and secreted, soluble tumor necrosis factor receptor 1, and tissue inhibitors of metalloproteinases. Activation of RAW 264.7 cells triggered by PRA-1p was associated with activation of inducible nitric oxide synthase, nuclear factor κB, extracellular signal-regulated kinase, and protein kinase B. This work suggests that novel PRA-1p derived from the mushroom sclerotia of P. rhinocerus has potential application as an immunostimulatory agent.

(2S)-2'-methoxykurarinone from Sophora flavescens suppresses cutaneous T cell-attracting chemokine/CCL27 expression induced by interleukin-ß/tumor necrosis factor-α via heme oxygenase-1 in human keratinocytes.

One of the CC chemokines, cutaneous T cell-attracting chemokine (CTACK/CCL27), is a skin-specific CC chemokine that is produced constitutively by keratinocytes and is highly up-regulated in inflammatory skin conditions such as atopic dermatitis and contact dermatitis. (2S)-2'-Methoxykurarinone (MOK) from Sophora flavescens has been demonstrated to have antioxidant effects. Heme oxygenase (HO)-1 has recently emerged as an important cytoprotective enzyme against oxidative stress and inflammatory responses in many cell types. This study aimed to define whether and how MOK regulates skin specific CTACK/CCL27 chemokine production in human HaCaT keratinocytes. The level of CTACK/CCL27 and HO-1 expression was measured by reverse transcription-polymerase chain reaction, and signaling was evaluated by western blot analysis. CTACK/CCL27 production was determined by enzyme-linked immunosorbent assay. Pretreatment with MOK suppressed tumor necrosis factor-α (TNF-α)- and interleukin (IL)-1ß-induced CTACK/CCL27 production in human HaCaT keratinocytes. MOK inhibited TNF-α- and IL-1ß-induced nuclear factor κB (NF-κB) activation. Interestingly, pretreatment with MOK significantly suppressed TNF-α- and IL-1ß-induced CTACK/CCL27 production through the induction of HO-1. This suppression was completely abolished by HO-1 small interfering RNA. Furthermore, carbon monoxide, but not other end products of HO-1 activity, also suppressed TNF-α- and IL-1ß-induced CTACK/CCL27 production. These results demonstrate that MOK attenuates TNF-α- and IL-1ß-induced production of CTACK/CCL27 in human HaCaT keratinocytes by inhibiting NF-κB activation and induction of HO-1.

Diarylheptanoid hirsutenone prevents tumor necrosis factor-alpha-stimulated production of inflammatory mediators in human keratinocytes through NF-kappaB inhibition.

Keratinocytes may play an important role in the pathogenesis of skin disease in atopic dermatitis. Diarylheptanoids such as oregonin and hirstanonol are demonstrated to have anti-inflammatory and anti-oxidant effects. The present study was to investigate the effect of hirsutenone, one of the diarylheptanoids, against tumor necrosis factor (TNF)-alpha-stimulated responses in human keratinocytes. Hirsutenone attenuated the TNF-alpha-induced production of cytokine IL-8, prostaglandin E(2) and chemokine CCL27, and the formation of reactive oxygen/nitrogen species in keratinocytes. Immunosuppressants (dexamethasone and cyclosporin A) inhibited the TNF-alpha-elicited formation of IL-8, prostaglandin E(2) and CCL27, but did not affect formation of reactive species. Bay 11-7085 (an inhibitor of NF-kappaB activation) and anti-oxidant N-acetylcysteine attenuated the TNF-alpha-induced formation of inflammatory mediators and reactive species. Hirsutenone, dexamethasone, cyclosporin A and Bay 11-7085 inhibited the TNF-alpha-induced phosphorylation of inhibitory kappaB and the activation of nuclear factor (NF)-kappaB. The results show that hirsutenone seems to reduce the TNF-alpha-stimulated production of inflammatory mediators in keratinocytes by suppressing the activation of NF-kappaB that may be mediated by reactive oxygen species. The findings suggest that hirsutenone may exert an inhibitory effect against the pro-inflammatory mediator-induced skin disease.