Inflammatory and Immunomodulatory Effects of Tripterygium wilfordii Multiglycoside in Mouse Models of Psoriasis Keratinocytes.

OBJECTIVE: To determine the role of Tripterygium wilfordii multiglycoside (TGW) in the treatment of psoriatic dermatitis from a cellular immunological perspective. METHODS: Mouse models of psoriatic dermatitis were established by imiquimod (IMQ). Twelve male BALB/c mice were assigned to IMQ or IMQ+TGW groups according to a random number table. Histopathological changes in vivo were assessed by hematoxylin and eosin staining. Ratios of immune cells and cytokines in mice, as well as PAM212 cell proliferation in vitro were assessed by flow cytometry. Pro-inflammatory cytokine expression was determined using reverse transcription quantitative polymerase chain reaction. RESULTS: TGW significantly ameliorated the severity of IMQ-induced psoriasis-like mouse skin lesions and restrained the activation of CD45+ cells, neutrophils and T lymphocytes (all P<0.01). Moreover, TGW significantly attenuated keratinocytes (KCs) proliferation and downregulated the mRNA levels of inflammatory cytokines including interleukin (IL)-17A, IL-23, tumor necrosis factor α, and chemokine (C-X-C motif) ligand 1 (P<0.01 or P<0.05). Furthermore, it reduced the number of γ δ T17 cells in skin lesion of mice and draining lymph nodes (P<0.01). CONCLUSIONS: TGW improved psoriasis-like inflammation by inhibiting KCs proliferation, as well as the associated immune cells and cytokine expression. It inhibited IL-17 secretion from γ δ T cells, which improved the immune-inflammatory microenvironment of psoriasis.

Genetic deletion of Cyp4f18 disrupts the omega-3 epoxidation pathway and results in psoriasis-like dermatitis.

Cyp4f18 catalyzes the conversion of n-3 polyunsaturated fatty acids (PUFAs) into omega-3 epoxides, such as 17,18-epoxyeicosatetraenoic acid (17,18-EpETE) and 19,20-epoxydocosapentaenoic acid (19,20-EpDPE) from eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), respectively. Cyp4f18-deficient mice spontaneously develop psoriasis-like dermatitis. A significant increase in the number of IL-17A-positive gamma delta (γδ) T cells in the skin and enlargement of draining lymph nodes was observed. These symptoms were drastically suppressed by antibiotic treatment. Cyp4f18 is highly expressed in dendritic cells (DCs), and Cyp4f18-deficient bone marrow-derived dendritic cells (BMDCs) show markedly increased expression levels of cytokines such as IL-23 and IL-1ß in response to lipopolysaccharide (LPS) stimulation. Lipidomic analysis of lymph nodes and BMDCs revealed a significant decrease in a series of omega-3 epoxidized metabolites. Among them, 17,18-dihydroxyeicosatetraenoic acid (17,18-diHETE), a vicinal diol derived from EPA omega-3 epoxidation suppressed IL-23 production in LPS-stimulated BMDCs in Cyp4f18-deficient mice. These results demonstrate that Cyp4f18 endogenously produces omega-3-epoxidized metabolites in the draining lymph nodes, and these metabolites contribute to skin homeostasis by suppressing the excessive activation of the IL-23/IL-17 axis initiated by DCs.

Selenium-Rich Yeast Peptide Fraction Ameliorates Imiquimod-Induced Psoriasis-like Dermatitis in Mice by Inhibiting Inflammation via MAPK and NF-κB Signaling Pathways.

Psoriasis, a chronic and immune-mediated inflammatory disease, adversely affects patients' lives. We previously prepared selenium-rich yeast peptide fraction (SeP) from selenium-rich yeast protein hydrolysate and found that SeP could effectively alleviate ultraviolet radiation-induced skin damage in mice and inhibited H2O2-induced cytotoxicity in cultured human epidermal keratinocyte (HaCaT) cells. This study aimed to investigate whether SeP had a protective effect on imiquimod (IMQ)-induced psoriasis-like dermatitis in mice and the underlying mechanisms. Results showed that SeP significantly ameliorated the severity of skin lesion in IMQ-induced psoriasis-like mouse model. Moreover, SeP treatment significantly attenuated the expression of key inflammatory cytokines, including interleukin (IL)-23, IL-17A, and IL-17F, in the dorsal skin of mice. Mechanistically, SeP application not only inhibited the activation of JNK and p38 MAPK, but also the translocation of NF-κB into the nucleus in the dorsal skin. Furthermore, SeP treatment inhibited the levels of inflammatory cytokines and the activation of MAPK and NF-κB signaling induced by lipopolysaccharide in HaCaT cells and macrophage cell line RAW264.7. Overall, our findings showed that SeP alleviated psoriasis-like skin inflammation by inhibiting MAPK and NF-κB signaling pathways, which suggested that SeP would have a potential therapeutic effect against psoriasis.

Intense Pulsed Light Attenuates UV-Induced Hyperimmune Response and Pigmentation in Human Skin Cells.

The skin of an organism is affected by various environmental factors and fights against aging stress via mechanical and biochemical responses. Photoaging induced by ultraviolet B (UVB) irradiation is common and is the most vital factor in the senescence phenotype of skin, and so, suppression of UVB stress-induced damage is critical. To lessen the UVB-induced hyperimmune response and hyperpigmentation, we investigated the ameliorative effects of intense pulsed light (IPL) treatment on the photoaged phenotype of skin cells. Normal human epidermal keratinocytes and human epidermal melanocytes were exposed to 20 mJ/cm2 of UVB. After UVB irradiation, the cells were treated with green (525-530 nm) and yellow (585-592 nm) IPL at various time points prior to the harvest step. Subsequently, various signs of excessive immune response, including expression of proinflammatory and melanogenic genes and proteins, cellular oxidative stress level, and antioxidative enzyme activity, were examined. We found that IPL treatment reduced excessive cutaneous immune reactions by suppressing UVB-induced proinflammatory cytokine expression. IPL treatment prevented hyperpigmentation, and combined treatment with green and yellow IPL synergistically attenuated both processes. IPL treatment may exert protective effects against UVB injury in skin cells by attenuating inflammatory cytokine and melanogenic gene overexpression, possibly by reducing intracellular oxidative stress. IPL treatment also preserves antioxidative enzyme activity under UVB irradiation. This study suggests that IPL treatment is a useful strategy against photoaging, and provides evidence supporting clinical approaches with non-invasive light therapy.

Interleukin-19 as an Immunoregulatory Cytokine.

IL-19 is a type of anti-inflammatory cytokine. Since the receptor for IL-19 is common to IL-20 and IL-24, it is important to clarify the role of each of the three cytokines. If three different cytokines bind to the same receptor, these three may have been produced to complement the other two. However, perhaps it is unlikely. Recently, the existence of a novel receptor for IL-19 was suggested. The distinction between the roles of the three cytokines still makes sense. On the other hand, because T cells do not produce IL-19, their role in acquired immunity is limited or indirect. It has been reported that IL-19 causes inflammation in some diseases but does not have an anti-inflammatory effect. In this review, we introduce the current role of IL-19 in each disease. In addition, we will describe the molecular mechanism of IL-19 and its development for the prevention of diseases. IL-19 was previously considered an anti-inflammatory cytokine, but we would like to propose it as an immunoregulatory cytokine.

Solidagenone from Solidago chilensis Meyen inhibits skin inflammation in experimental models.

Solidagenone (SOL) is a labdane-type diterpenoid found in Solidago chilensis, a plant traditionally used to treat skin diseases, kidney pain and ovarian inflammation. In this study, the topical anti-inflammatory activity of SOL was evaluated using in vivo and in silico assays. Croton oil-, arachidonic acid (AA)- and phenol-induced ear oedema mouse models were applied in the in vivo studies. Myeloperoxidase (MPO) and N-acetyl-ß-D-glucosaminidase (NAG) activities and tumour necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and nitric oxide (NO) levels were determined, as well as histopathological analyses were conducted. Interaction profiles between SOL and cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), glucocorticoid receptor, estradiol-17-ß-dehydrogenase and prostaglandin-E(2)-9-reductase were established using molecular docking. SOL significantly inhibited croton oil-, AA- and phenol-induced ear oedema (P < .001) at doses of 0.1, 0.5 and 1.0 mg/ear. The MPO and NAG activities and TNF-α, IL-6 and NO levels were decreased (P < .001). The histopathological data revealed that inflammatory parameters (oedema thickness, leucocyte infiltration and vasodilatation) were reduced by treatment with SOL at doses of 0.1, 0.5 and 1.0 mg/ear. The docking study showed that SOL interacts with COX-1 and prostaglandin-E(2)-9-reductase through hydrogen bonding, inhibiting these enzymes. These results indicate that SOL may be a promising compound for the treatment of cutaneous inflammatory disorders and has potential as a topical anti-inflammatory agent.

Omega-3 Versus Omega-6 Polyunsaturated Fatty Acids in the Prevention and Treatment of Inflammatory Skin Diseases.

Omega-3 (ω-3) and omega-6 (ω-6) polyunsaturated fatty acids (PUFAs) are nowadays desirable components of oils with special dietary and functional properties. Their therapeutic and health-promoting effects have already been established in various chronic inflammatory and autoimmune diseases through various mechanisms, including modifications in cell membrane lipid composition, gene expression, cellular metabolism, and signal transduction. The application of ω-3 and ω-6 PUFAs in most common skin diseases has been examined in numerous studies, but their results and conclusions were mostly opposing and inconclusive. It seems that combined ω-6, gamma-linolenic acid (GLA), and ω-3 long-chain PUFAs supplementation exhibits the highest potential in diminishing inflammatory processes, which could be beneficial for the management of inflammatory skin diseases, such as atopic dermatitis, psoriasis, and acne. Due to significant population and individually-based genetic variations that impact PUFAs metabolism and associated metabolites, gene expression, and subsequent inflammatory responses, at this point, we could not recommend strict dietary and supplementation strategies for disease prevention and treatment that will be appropriate for all. Well-balanced nutrition and additional anti-inflammatory PUFA-based supplementation should be encouraged in a targeted manner for individuals in need to provide better management of skin diseases but, most importantly, to maintain and improve overall skin health.

Spilanthol Inhibits Inflammatory Transcription Factors and iNOS Expression in Macrophages and Exerts Anti-inflammatory Effects in Dermatitis and Pancreatitis.

Activated macrophages upregulate inducible nitric oxide synthase (iNOS) leading to the profuse production of nitric oxide (NO) and, eventually, tissue damage. Using macrophage NO production as a biochemical marker of inflammation, we tested different parts (flower, leaf, and stem) of the medicinal plant, Spilanthes acmella. We found that extracts prepared from all three parts, especially the flowers, suppressed NO production in RAW macrophages in response to interferon-γ and lipopolysaccharide. Follow up experiments with selected bioactive molecules from the plant (α-amyrin, ß-caryophylline, scopoletin, vanillic acid, trans-ferulic acid, and spilanthol) indicated that the N-alkamide, spilanthol, is responsible for the NO-suppressive effects and provides protection from NO-dependent cell death. Spilanthol reduced the expression of iNOS mRNA and protein and, as a possible underlying mechanism, inhibited the activation of several transcription factors (NFκB, ATF4, FOXO1, IRF1, ETS, and AP1) and sensitized cells to downregulation of Smad (TF array experiments). The iNOS inhibitory effect translated into an anti-inflammatory effect, as demonstrated in a phorbol 12-myristate 13-acetate-induced dermatitis and, to a smaller extent, in cerulein-induced pancreatitis. In summary, we demonstrate that spilanthol inhibits iNOS expression, NO production and suppresses inflammatory TFs. These events likely contribute to the observed anti-inflammatory actions of spilanthol in dermatitis and pancreatitis.

Optimization and Evaluation of Beclomethasone Dipropionate Micelles Incorporated into Biocompatible Hydrogel Using a Sub-Chronic Dermatitis Animal Model.

The current study is concerned with the development and characterization of mixed micelles intended for the dermal delivery of beclomethasone dipropionate, which is a topical corticosteroid used in the management of atopic dermatitis. Mixed micelles were prepared using thin-film hydration technique, employing different concentrations of pluronic L121 with either poloxamer P84 or pluronic F127 with different surfactant mixture-to-drug ratios. The prepared formulae were characterized concerning entrapment efficiency, particle size, and zeta potential. Two formulae were chosen for ex vivo skin deposition studies: one formulated using pluronic L121/poloxamer P84 mixture while the other using pluronic L121/pluronic F127 mixture. The optimum formula with the highest dermal deposition was subjected to morphological examination and was formulated as hydroxypropyl methylcellulose hydrogel. The hydrogel was evaluated regarding viscosity and was subjected to ex vivo deposition study in comparison with the commercially available cream Beclozone®. In vivo histopathological study was conducted for both the hydrogel and Beclozone® in order to evaluate their healing efficiency. In vivo histopathological study results showed that the prepared hydrogel successfully treated sub-chronic dermatitis in an animal model within a shorter period of time compared to Beclozone®, resulting in better patient compliance and fewer side effects.

Oenanthe Javanica Extract Protects Mouse Skin from UVB Radiation via Attenuating Collagen Disruption and Inflammation.

In recent years, the use of botanical agents to prevent skin damage from solar ultraviolet (UV) irradiation has received considerable attention. Oenanthe javanica is known to exert anti-inflammatory and antioxidant activities. This study investigated photoprotective properties of an Oenanthe javanica extract (OJE) against UVB-induced skin damage in ICR mice. The extent of skin damage was evaluated in three groups: control mice with no UVB, UVB-exposed mice treated with vehicle (saline), and UVB-exposed mice treated with 1% extract. Photoprotective properties were assessed in the dorsal skin using hematoxylin and eosin staining, Masson trichrome staining, immunohistochemical staining, quantitative real-time polymerase chain reaction, and western blotting to analyze the epidermal thickness, collagen expression, and mRNA and protein levels of type I collagen, type III collagen, and interstitial collagenases, including matrix metalloproteinase (MMP)-1 and MMP-3. In addition, tumor necrosis factor (TNF)-α and cyclooxygenase (COX)-2 protein levels were also assessed. In the UVB-exposed mice treated with extract, UV-induced epidermal damage was significantly ameliorated. In this group, productions of collagen types I and III were increased, and expressions of MMP-1 and MMP-3 were decreased. In addition, TNF-α and COX-2 expressions were reduced. Based on these findings, we conclude that OJE displays photoprotective effects against UVB-induced collagen disruption and inflammation and suggest that Oenanthe javanica can be used as a natural product for the treatment of photodamaged skin.

PSORI-CM02 alleviates IMQ-induced mouse dermatitis via differentially regulating pro- and anti-inflammatory cytokines targeting of Th2 specific transcript factor GATA3.

The IL-17-producing CD4+ T cell and γδT cells play critical roles in the pathogenesis of psoriasis (PS). PSORI-CM02 is a representative herbal formula for the treatment for PS in South China. It was confirmed to improve PS without obvious side effects in the clinic. Here we sought to clarify whether and how PSORI-CM02 regulates T cell differentiation and functions in IMQ-induced psoriasis-like BALB/c mouse model. Mice pre-treated 3 days with PSORI-CM02 significantly alleviated skin inflammation, as reduced in PASI score and classic psoriatic characteristics in pathological sections. CD3 and CD4 positive T cells were also fewer in the skin lesions of PSORI-CM02 groups, comparing to control group. PSORI-CM02 also decreased pro-inflammatory IFNγ mRNA and IL-17 A mRNA, while increased IL-4 mRNA in mouse skin lesions. In skin draining lymph nodes (DLN), PSORI-CM02 reduced the ratio of γδT cells and inhibited their function of producing IL-17 A. Nevertheless PSORI-CM02 had no effects on the ratio of total TCRß+T cells and CD4 + T cells. But it regulated CD4 + T helper cells differentiation, and resulted in the decreasing percentage of IFNγ producing Th1 cells and IL-17 A producing Th17 cells, while increasing the ratio of IL-4 producing Th2 cells in DLN. Further data showed that PSORI-CM02 promote expression of Th2 specific transcript factor GATA3, but had no effects on T-bet and RORγ. Thus, we tentatively interpret that PSORI-CM02 impairs IMQ-induced psoriasis by promoting Th2 cell response targeting of GATA3.

Rutaecarpine inhibited imiquimod-induced psoriasis-like dermatitis via inhibiting the NF-κB and TLR7 pathways in mice.

Psoriasis is a chronic, immune-mediated inflammatory skin disease. As psoriasis rarely occurs in nonhuman animals, the lack of an ideal animal model reflecting the histopathological and molecular immunological characteristics of psoriasis remains an urgent issue. In the present study, an imiquimod-induced psoriasis-like dermatitis mouse model was constructed under natural immune conditions and verified by evaluations of the Psoriasis Area and Severity Index (PASI) score and Baker score, H&E staining, immunohistochemical examination of the CD3 and Gr1 levels, measurement of plasmacytoid dendritic cell- (pDC) and Th17-associated cytokine levels, and evaluation of p65 phosphorylation and TLR7 expression. Moreover, rutaecarpine (RUT), the main active ingredient in the traditional Chinese medicine Wu-Zhu-Yu, could improve psoriasis-like dermatitis through effects on pDC- and Th17-associated cytokines through NF-κB and toll-like receptor 7 (TLR7) signaling. Taken together, the imiquimod-induced psoriasis-like dermatitis mouse model can be regarded as an ideal model for evaluating psoriasis pathogenesis and antipsoriatic drugs. We provided theoretical and experimental evidence for the clinical application of RUT in psoriasis.

Resolvin E1 attenuates murine psoriatic dermatitis.

The potential of omega-3 poly-unsaturated fatty acids (PUFAs) as a therapeutic target for psoriasis, a chronic inflammatory skin disease of IL-23/IL-17 axis, is a long-disputed question, since various epidemiological studies have suggested the association between high-intake of omega-3 PUFAs and the reduced frequency and severity of psoriasis. However, their actual significance and the molecular mechanisms remain largely unknown. To address these issues, we focused on resolvin E1 (RvE1), an omega-3 PUFAs-derived metabolite, and examined its effects on psoriatic dermatitis, using an imiquimod-induced mouse psoriasis model. RvE1 potently suppressed the inflammatory cell infiltration and epidermal hyperplasia in the psoriatic skin. RvE1 decreased the mRNA expression of IL-23 in the skin. Consistently, RvE1 inhibited IL-23 production by dendritic cells (DCs) in vitro. Furthermore, RvE1 exerted inhibitory effects on migration of cutaneous DCs and γδ T cells, a major IL-17-producing cell population in mouse, both in vivo and in vitro. These suppressive effects of RvE1 were mediated by its antagonistic function on BLT1, a receptor of leukotriene B4, and were also observed in human DCs, Th17 and Tc17 cells. Our results indicate a novel mechanism of omega-3 PUFA-mediated amelioration of psoriasis, and suggest a potential of RvE1 as a therapeutic target for psoriasis.

Daily very low UV dose exposure enhances adaptive immunity, compared with a single high-dose exposure. Consequences for the control of a skin infection.

Ultraviolet radiation (UVr) promotes several well-known molecular changes, which may ultimately impact on health. Some of these effects are detrimental, like inflammation, carcinogenesis and immunosuppression. On the other hand, UVr also promotes vitamin D synthesis and other beneficial effects. We recently demonstrated that exposure to very low doses of UVr on four consecutive days [repetitive low UVd (rlUVd)] does not promote an inflammatory state, nor the recruitment of neutrophils or lymphocytes, as the exposure to a single high UV dose (shUVd) does. Moreover, rlUVd reinforce the epithelium by increasing antimicrobial peptides transcription and epidermal thickness. The aim of this study was to evaluate the adaptive immune response after shUVd and rlUVd, determining T-cell and B-cell responses. Finally, we challenged animals exposed to both irradiation procedures with Staphylococcus aureus to study the overall effects of both innate and adaptive immunity during a cutaneous infection. We observed, as expected, a marked suppression of T-cell and B-cell responses after exposure to an shUVd but a novel and significant increase in both specific responses after exposure to rlUVd. However, the control of the cutaneous S. aureus infection was defective in this last group, suggesting that responses against pathogens cannot be ruled out from isolated stimuli.

Potential inhibitory effects of the traditional herbal prescription Hyangso-san against skin inflammation via inhibition of chemokine production and inactivation of STAT1 in HaCaT keratinocytes.

Inflammatory skin disease are caused by multiple factors, including susceptibility genes, and immunologic and environmental factors, and are characterized by an increase in epidermal thickness and the infiltration of macrophages, keratinocytes, mast cells, eosinophils and other inflammatory cells. Keratinocytes may serve an important role in the pathogenesis of inflammatory skin diseases. The traditional herbal decoction Hyangso­san (HSS) has been used to treat symptoms of the common cold, including headache, pantalgia, fever and chills. However, to the best of our knowledge, there is no evidence regarding whether HSS has an effect on inflammatory skin diseases. The present study investigated the anti­skin inflammation activity of HSS using the HaCaT human keratinocyte cell line. The mRNA expression and production of inflammatory chemokines, including C­C motif chemokine ligand 22 (CCL22), CCL5, CCL17, and interleukin (IL)­8, was measured using reverse transcription polymerase chain reaction and ELISA analyses. Moreover, we evaluated the effect of HSS on signal transducer and activator of transcription 1 (STAT1) pathway in HaCaT cells. The cells were stimulated with tumor necrosis factor­α (TNF­α) and interferon­Î³ (IFN­Î³) to induce an inflammatory reaction. In the TNF­α­ and IFN­Î³­stimulated cells, the production and expression of inflammatory chemokines were observed, including CCL22, CCL5, CCL17 and IL­8. In addition, stimulation with TNF­α and IFN­Î³ increased the phosphorylation and nuclear translocation of STAT1 in HaCaT cells. By contrast, HSS extract treatment inhibited TNF­α­ and IFN­Î³­induced STAT1 activation. Results from the present study indicated that HSS exhibited inhibitory effects on TNF­α­ and IFN­Î³­mediated chemokine production and expression by targeting STAT1 in keratinocytes. Overall, the results indicated that HSS may be a potential candidate therapeutic drug for inflammatory skin diseases such as atopic dermatitis.

Is there a future for andrographolide to be an anti-inflammatory drug? Deciphering its major mechanisms of action.

Andrographis paniculata has long been part of the traditional herbal medicine system in Asia and in Scandinavia. Andrographolide was isolated as a major bioactive constituent of A. paniculata in 1951, and since 1984, andrographolide and its analogs have been scrutinized with modern drug discovery approach for anti-inflammatory properties. With this accumulated wealth of pre-clinical data, it is imperative to review and consolidate different sources of information, to decipher the major anti-inflammatory mechanisms of action in inflammatory diseases, and to provide direction for future studies. Andrographolide and its analogs have been shown to provide anti-inflammatory benefits in a variety of inflammatory disease models. Among the diverse signaling pathways investigated, inhibition of NF-κB activity is the prevailing anti-inflammatory mechanism elicited by andrographolide. There is also increasing evidence supporting endogenous antioxidant defense enhancement by andrographolide through Nrf2 activation. However, the exact pathway leading to NF-κB and Nrf2 activation by andrographolide has yet to be elucidated. Validation and consensus on the major mechanistic actions of andrographolide in different inflammatory conditions are required before translating current findings into clinical settings. There are a few clinical trials conducted using andrographolide in fixed combination formulation which have shown anti-inflammatory benefits and good safety profile. A concerted effort is definitely needed to identify potent andrographolide lead compounds with improved pharmacokinetics and toxicological properties. Taken together, andrographolide and its analogs have great potential to be the next new class of anti-inflammatory agents, and more andrographolide molecules are likely moving towards clinical study stage in the near future.

Paeonol suppresses solar ultraviolet-induced skin inflammation by targeting T-LAK cell-originated protein kinase.

Excessive exposure to solar UV (SUV) is related with numerous human skin disorders, such as skin inflammation, photoaging and carcinogenesis. T-LAK cell- originated protein kinase (TOPK), an upstream of p38 mitogen-activated protein kinase (p38) and c-Jun N-terminal kinases (JNKs), plays an important role in SUV -induced skin inflammation, and targeting TOPK has already been a strategy to prevent skin inflammation. In this study, we found that the expression of TOPK, phosphorylation of p38 or JNKs was increased in human solar dermatitis tissues. The level of phosphorylation of p38 or JNKs increased in a dose and time dependent manner in HaCat cells or JB6 Cl41 cells after SUV treatment. Paeonol is an active component isolated from traditional Chinese herbal medicines, and MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2H-tetrazdium) assay showed that it has no toxicity to cells. Microscale thermophoresis (MST) assay showed that paeonol can bind TOPK ex vivo. In vitro kinase assay showed paeonol can inhibit TOPK activity. Ex vivo studies further showed paeonol suppressed SUV-induced phosphorylation level of p38, JNKs, MSK1 and histone H2AX by inhibiting TOPK activity in a time and dose dependent manner. Paeonol inhibited the secretion of IL-6 and TNF-α in HaCat and JB6 cells ex vivo. In vivo studies demonstrated that paeonol inhibited SUV-induced increase of TOPK, the phosphorylation of p38, JNKs and H2AX, and the secretion of IL-6 and TNF-α in Babl/c mouse. In summary, our data indicated a protective role of paeonol against SUV-induced inflammation by targeting TOPK, and paeonol could be a promising agent for the treatment of SUV-induced skin inflammation.

The Preventive Effect of Coffee Compounds on Dermatitis and Epidermal Pigmentation after Ultraviolet Irradiation in Mice.

BACKGROUND: Ultraviolet (UV) irradiation is well known to promote inflammation and pigmentation of skin. UVB mainly affects dermatitis and pigmentation. Coffee contains a number of polyphenols, such as caffeic acid (CA) and chlorogenic acid (CGA) but their in vivo bioactivity for photobiology remains unclear. METHODS: C57BL/6j male mice were irradiated with UVB (1.0 kJ/m2/day) for 3 days. Five days after the final session of UVB irradiation, the dorsal skin, ear epidermis, and blood samples were analyzed to investigate the inflammatory factors, melanogenesis factors and related hormones. RESULTS: After the oral administration of CA (100 mg/day) or CGA (100 mg/day) for 8 days, only CA was found to inhibit dermatitis and pigmentation. The pathway by which CA inhibits dermatitis is related to the mitogen-activated protein kinase (MAPK)/extracellular signal regulated kinase (ERK)1/2/cAMP response element binding protein (CREB) pathway. Otherwise, the pathway by which CA inhibits pigmentation is related to the activation of the ß-endorphin-µ-opioid receptor and suppresses the cAMP-microphthalmia-associated transcription factor (MITF) pathway. CONCLUSION: It is suggested that the oral administration of CA prevented dermatitis and pigmentation after UVB irradiation in mice.

Anti-inflammatory actions of herbal formula Gyejibokryeong-hwan regulated by inhibiting chemokine production and STAT1 activation in HaCaT cells.

Gyejibokryeong-hwan (GJBRH; Keishi-bukuryo-gan in Japan and Guizhi Fuling Wan in China) is a traditional herbal formula comprising five medicinal herbs and is used to treat climacteric syndrome. GJBRH has been shown to exhibit biological activity against diabetes, diabetic nephropathy, atherosclerosis, ischemia, and cancer. However, there is no scientific evidence of its activities against skin inflammation, including atopic dermatitis. We used the HaCaT human keratinocyte cell line to investigate the effects of GJBRH on skin inflammation. No significant cytotoxicity was observed in cells treated with GJBRH up to a concentration of 1000 µg/mL. Exposure to the proinflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) significantly increased HaCaT cell production of the following chemokines: macrophage-derived chemokine (MDC)/CCL22; regulated on activation, normal T-cell expressed and secreted (RANTES)/CCL5; and interleukin-8 (IL-8). In contrast, GJBRH significantly reduced the production of MDC, RANTES, and IL-8 compared with control cells simulated with TNF-α and IFN-γ. Consistently, GJBRH suppressed the mRNA expression of MDC, RANTES, and IL-8 in TNF-α and IFN-γ-treated cells. Treatment with GJBRH markedly inhibited phosphorylation of signal transducer and activator of transcription 1 (STAT1) in HaCaT cells stimulated with TNF-α and IFN-γ. Our findings indicate that GJBRH impairs TNF-α and IFN-γ-mediated inflammatory chemokine production and STAT1 phosphorylation in keratinocytes. We suggest that GJBRH may be a potent therapeutic agent for inflammatory skin disorders.

Role of macrophage migration inhibitory factor (MIF) in pollen-induced allergic conjunctivitis and pollen dermatitis in mice.

Pollen is a clinically important airborne allergen and one of the major causes of allergic conjunctivitis. A subpopulation of patients with atopic dermatitis (AD) are also known to have exacerbated skin eruptions on the face, especially around the eyelids, after contact with pollen. This pollen-induced skin reaction is now known as pollen dermatitis. Macrophage migration inhibitory factor (MIF) is a pluripotent cytokine that plays an essential role in allergic inflammation. Recent findings suggest that MIF is involved in several allergic disorders, including AD. In this study, MIF knockout (KO), MIF transgenic (Tg) and WT littermate mice were immunized with ragweed (RW) pollen or Japanese cedar (JC) pollen and challenged via eye drops. We observed that the numbers of conjunctiva- and eyelid-infiltrating eosinophils were significantly increased in RW and JC pollen-sensitized MIF Tg compared with WT mice or MIF KO mice. The mRNA expression levels of eotaxin, interleukin (IL)-5 and IL-13 were increased in pollen-sensitized eyelid skin sites of MIF Tg mice. An in vitro analysis revealed that high eotaxin expression was induced in dermal fibroblasts by MIF combined with stimulation of IL-4 or IL-13. This eotaxin expression was inhibited by the treatment with CD74 siRNA in fibroblasts. These findings indicate that MIF can induce eosinophil accumulation in the conjunctiva and eyelid dermis exposed to pollen. Therefore, targeted inhibition of MIF might result as a new option to control pollen-induced allergic conjunctivitis and pollen dermatitis.