Altered T cell subpopulations and serum anti-TYRP2 and tyrosinase antibodies in the acute and chronic phase of alopecia areata in the C3H/HeJ mouse model.

BACKGROUND: C3H/HeJ mouse models progress gradually in hair loss from acute to chronic phase and reflect the symptoms of patients with alopecia areata (AA). However, the underlying pathological characteristics alteration associated with disease progression and autoantigens remain unclear. OBJECTIVE: We aimed at elucidating the pathological differences between acute and chronic-AA in the C3H/HeJ mouse model. METHODS: We analyzed populations of PBMCs, skin-draining lymph node (SDLN) cells, and cutaneous cells of AA mice using flow cytometry. The cytokine and chemokine expressions in the serum and skin were determined using multiplex assay and qPCR. The antibody serum levels were determined using ELISA and the antigen-specific T cells were detected using the MHC class I tetramer. RESULTS: The CD8+NKG2D+ T and CD8+ TEM cell percentage in the chronic-AA SDLNs or among the unaffected and acute-AA mice PBMCs increased. The Th1 and CD4+ TEM cell percentage in the SDLNs and among PBMCs increased in the unaffected and AA mice. The percentage of CD8+ TEM/TRM cells and MHC class I expression increased in the lesions of acute-AA or the non-lesions and lesions of chronic-AA. The Th1 cells, dendritic cell-related cytokines, CD11c+ cells and MHC class II expression increased in the skin of AA mice. The antibody levels and TYRP2 and tyrosinase-specific CD8+ T cell percentages were upregulated in AA mice. CONCLUSION: These results suggest that the CD8+ and CD4+ T cell subpopulations, cytokine and chemokine expressions differ between the disease phases. Moreover, TYRP2 and tyrosinase are potential autoreactive targets in the AA mouse model.

Anti-inflammatory effects of ozenoxacin, a topical quinolone antimicrobial agent.

Ozenoxacin is a topical quinolone showing potent antimicrobial activities against Gram-negative and Gram-positive bacteria and is widely used for the treatment of inflammatory acne. However, the anti-inflammatory activities of ozenoxacin have not been examined so far. In the present study, we investigated the in vitro and in vivo anti-inflammatory effects of ozenoxacin. The production of interleukin (IL)-6 and IL-8 by human epidermal keratinocytes stimulated by heat-killed Cutibacterium acnes was significantly inhibited by ozenoxacin at concentrations from 1 to 30 µg ml-1. Likewise, the production of IL-6, IL-8, and tumor necrosis factor alpha by stimulated THP-1 cells, a human monocyte cell line, was inhibited by ozenoxacin at concentrations from 1 to 30 µg ml-1. The production of IL-1ß by THP-1 was also inhibited by ozenoxacin at the concentration of 30 µg ml-1. Phosphorylation of the mitogen-activated protein kinases and degradation of IκB-α, an inhibitory factor of NF-κB in keratinocytes and THP-1 cells, was increased by stimulation with heat-killed C. acnes. Of these activated intracellular pathways, the p38 phosphorylation pathway was remarkably reduced by ozenoxacin in both keratinocytes and THP-1 cells. In addition, the application of 2% ozenoxacin suppressed the increase in the ear thickness of rats induced by an intracutaneous injection of heat-killed C. acnes. These findings suggest that ozenoxacin possesses an anti-inflammatory activity, which may contribute to its therapeutic effects on inflammatory acne.

Anti-inflammatory effect of lanoconazole on 12-O-tetradecanoylphorbol-13-acetate- and 2,4,6-trinitrophenyl chloride-induced skin inflammation in mice.

BACKGROUND: Lanoconazole (LCZ) is a topical antifungal agent clinically used to treat fungal infections such as tinea pedis. LCZ has not only antifungal effects but also anti-inflammatory effects, which have the potential to provide additional clinical benefits. However, the characteristic features of the inhibitory effects of LCZ on skin inflammation remain unclear. OBJECTIVE: We evaluated the inhibitory effects of topical application of LCZ, and compared the effects of LCZ with those of other antifungal agents including liranaftate, terbinafine and amorolfine. METHODS: Each antifungal agent was topically applied on 12-O-tetradecanoylphorbol-13-acetate-induced irritant dermatitis and 2,4,6-trinitrophenyl chloride-induced contact dermatitis in mice (BALB/c). The ear thickness, myeloperoxidase activity and inflammatory mediator contents were evaluated. RESULTS: LCZ dose-dependently suppressed 12-O-tetradecanoylphorbol-13-acetate-induced irritant dermatitis, suppressed the production of neutrophil chemotactic factors such as keratinocyte-derived chemokine and macrophage inflammatory protein-2, and inhibited neutrophil infiltration to the inflammation site. Moreover, 1% LCZ reduced the ear swelling in mice with 2,4,6-trinitrophenyl chloride-induced contact dermatitis in accordance with the inhibition of interferon-γ production. The inhibitory potency of LCZ on these types of dermatitis in mice was stronger than that of other types of antifungal agents. CONCLUSION: The anti-inflammatory effects of LCZ were exerted through the inhibition of inflammatory mediator production. These effects may contribute to the relief of dermatitis symptoms in patients with tinea pedis.

Anti-inflammatory activity of lanoconazole, a topical antifungal agent.

Topical antifungal agents which have anti-inflammatory effects have the potential to provide additional clinical benefits. Therefore, an anti-inflammatory activity of lanoconazole (LCZ), a topical antifungal agent, was investigated against in vitro and in vivo models of inflammation. The release of interleukin-8 (IL-8) from human epidermal keratinocytes stimulated by the addition of 100 µg ml(-1) ß-glucan of Saccharomyces cerevisiae was significantly inhibited by LCZ at the concentration of 10(-5) mol l(-1). The release of interferon-γ and IL-2 from human peripheral blood mononuclear cells stimulated by the addition of 30 and 100 µg ml(-1) phytohemagglutinin was significantly inhibited by LCZ at the concentrations of 10(-7) and 10(-6) mol l(-1), respectively. The increase in the ear thickness induced by topical application of 0.01% 12-O-tetradecanoyl phorbol-13-acetate and 1% 2,4,6-trinitrochlorobenzene (TNCB) after sensitisation with 3% TNCB were established as the mouse models of irritant and contact dermatitis, respectively. Application of 1% and 3% LCZ showed a significant anti-inflammatory activity against both the irritant and contact dermatitis models. These findings suggest that LCZ possesses an anti-inflammatory activity, which may be partially helpful in the treatment of dermatomycoses.

P2Y6 receptor signaling pathway mediates inflammatory responses induced by monosodium urate crystals.

Gout occurs in individuals with hyperuricemia when monosodium urate (MSU) crystals precipitate in tissues and induce acute inflammation via phagocytic cells such as monocytes. MSU crystals have been demonstrated in skin diseases such as tophaceous gout or psoriasis; however, the importance of MSU crystals in the skin is totally unknown. In this study, we found that MSU crystals, through P2Y(6) receptors, stimulated normal human keratinocytes (NHK) to produce IL-1α, IL-8/CXCL8, and IL-6. P2Y(6) receptor expression increased in MSU-stimulated NHK. Both P2Y(6)-specific antagonist and P2Y(6) antisense oligonucleotides significantly inhibited the production of IL-1α, IL-8/CXCL8, and IL-6 by NHK. Similarly, the P2Y(6)-specific antagonist completely inhibited the MSU-induced production of IL-1ß by THP-1 cells, a human monocytic cell line. Remarkably, the P2Y(6)-specific antagonist significantly reduced neutrophil influx in both mouse air pouch and peritonitis models. Thus, these results indicate that the P2Y(6) receptor signaling pathway may be a potential therapeutic target for MSU-associated inflammatory diseases, such as tophaceous gout.

High calcium, ATP, and poly(I:C) augment the immune response to ß-glucan in normal human epidermal keratinocytes.

ß-Glucans are pathogen-associated molecular patterns of fungi such as Candida albicans. Here, we studied their effects on normal human epidermal keratinocytes (NHEKs) from neonatal foreskin, and with high calcium to induce keratinocyte differentiation, danger signals, and pathogen-associated compounds such as adenosine 5'-triphosphate (ATP), poly(I:C), and lipopolysaccharide (LPS). ß-Glucan stimulation significantly increased IL-8, IL-6, and IL-1α production by NHEKs. Well-differentiated NHEKs produced elevated IL-8 levels, whereas ATP, a danger signal, significantly increased IL-8 and IL-6 production, and the pathogen-associated compound, poly(I:C), augmented IL-1α production by ß-glucan-stimulated NHEKs. No response to LPS from Escherichia coli was seen. Dectin-1 is known as the major receptor for ß-glucans on phagocytes and dendritic cells. Dectin-1 mRNA was detected in NHEKs by reverse transcription-PCR. Flow-cytometric analyses confirmed the NHEK cell surface expression of dectin-1. Immunoblotting showed that ß-glucan induced dual phosphorylation of p44/42 mitogen-activated protein kinase (MAPK) (extracellular signal-regulated kinase (ERK)1/2), and p38 MAPK in NHEKs; these signaling pathways are known to be associated with dectin-1. Treatment with the ERK inhibitor PD98059 and with the p38 kinase inhibitor SB203580 effectively suppressed ß-glucan-induced IL-8 production by NHEKs. Thus, high calcium, ATP, and poly(I:C) augment the cytokine and chemokine production by ß-glucan-stimulated NHEKs. Dectin-1 is present on NHEKs and may have an important role in cell response to ß-glucan.

Semaphorin 7A on keratinocytes induces interleukin-8 production by monocytes.

BACKGROUND: Semaphorin 7A (Sema7A) expressed on activated T cells stimulates cytokine production in monocytes through its receptor, α1ß1 integrin. OBJECTIVE: To study the significance of Sema7A expressed on keratinocytes in skin inflammation where interaction between keratinocytes and ß1-integrin expressing inflammatory cells, such as monocytes, takes place. METHODS: The regulation of Sema7A expression on keratinocytes by various cytokines was studied by flow cytometry and immunoblot. ß1-integrin expressing human monocyte cell line, THP-1 cells, were co-cultured with paraformaldehyde-fixed normal human epidermal keratinocytes (NHK) and IL-8 production by THP-1 cells was studied. The significance of ß1-integrin or Sema7A within this cell interaction was examined by the experiments using ß1-integrin blocking antibody or Sema7A siRNA. RESULTS: IFN-γ and TNF-α slightly increased Sema7A expression, while IL-4 decreased it. Among cytokines tested, TGF-ß1 most strikingly increased the Sema7A expression on NHK. When NHK was stimulated by TGF-ß1, paraformaldehyde-fixed, and co-cultured with THP-1 cells, IL-8 production by THP-1 cells was increased compared to THP-1 cells only. When THP-1 cells were pretreated with ß1-integrin blocking antibody, this increase in IL-8 production by THP-1 cells was inhibited. Likewise, when NHK were pretreated with Sema7A siRNA before fixation and co-cultured with THP-1 cells, increase in IL-8 production by THP-1 cells was inhibited. CONCLUSION: Our results suggest that Sema7A on keratinocytes and ß1-integrin on monocytes contribute to monocyte activation by keratinocytes within skin inflammation, such as psoriasis or wound.

Histamine differentially regulates the production of Th1 and Th2 chemokines by keratinocytes through histamine H1 receptor.

Histamine is a biological amine that plays an important role in allergic responses. However, the involvement of histamine signaling in late allergic responses in the skin is poorly understood. Therefore, we attempted to investigate the involvement of histamine signaling in late allergic responses, especially in keratinocytes (KCs). HaCaT KCs and normal human KCs (NHKs) predominantly expressed histamine H1 receptor (H1R) and H2 receptor (H2R). Histamine suppressed tumor necrosis factor α (TNF-α)- and interferon-γ (IFN-γ)-induced production of CC chemokine ligand 17(CCL17), a type 2 T-helper (Th2) chemokine, by HaCaT KCs. It suppressed the phosphorylation of p38 mitogen-activated protein (MAP) kinase, but not that of extracellular signal-regulated kinases (ERKs), and TNF-α- and IFN-γ-induced nuclear factor κB (NFκB) activity. In contrast, histamine enhanced the production of CXC chemokine ligand 10 (CXCL10), a Th1 chemokine, by TNF-α- and IFN-γ-stimulated HaCaT KCs and NHKs. TNF-α- and IFN-γ-induced CXCL10 production was upregulated by suppression of p38 MAP kinase or NF-κB activity, which could explain histamine involvement. We concluded that histamine suppresses CCL17 production by KCs by suppressing p38 MAP kinase and NF-κB activity through H1R and may act as a negative-feedback signal for existing Th2-dominant inflammation by suppressing CCL17 and enhancing CXCL10 production.

CCR4 and CCR10 are expressed on epidermal keratinocytes and are involved in cutaneous immune reaction.

CC chemokine ligand (CCL)17 and CCL27 produced by epidermal keratinocytes (KCs) recruit CC chemokine receptor (CCR)4 and CCR10 expressing T cells into the skin, respectively, resulting in enhanced skin inflammation. However, CCR4/CCL17 and CCR10/CCL27 interactions in epidermal KCs have not been investigated. The purpose of this study was to evaluate the role of the CCR4/CCL17 and CCR10/CCL27 loops in cutaneous immune reaction. Normal human KCs (NHKs) and HaCaT KCs expressed both CCR4 and CCR10 at mRNA and protein levels. CCR4 ligand CCL17 but not CCR10 ligand CCL27 induced production of IL-12 p40, granulocyte/monocyte colony-stimulating factor (GM-CSF) and nerve growth factor (NGF) by KCs. Both CCL17 and CCL27 induced migration of KCs in Boyden chamber assay and wound scratch assay. This study revealed that CCR4 and CCR10 are expressed on epidermal KCs and that both are functional in terms of skin cytokine production and/or migration to their ligand CCL17 and CCL27, respectively. Thus this study provided new insight into chemokine/chemokine receptors of KCs.