Dissolvable microneedles based on Panax notoginseng polysaccharide for transdermal drug delivery and skin dendritic cell activation.

This work explored the feasibility of using biological polysaccharide to fabricate dissolvable microneedles (MNs) for the purpose of transdermal drug delivery and skin dendritic cell (DC) activation. Panax notoginseng polysaccharide (PNPS), a naturally derived immunoactive macromolecule, was used to fabricate dissolvable MNs. The prepared PNPS MNs showed a satisfactory mechanical strength and a skin penetration depth. By Franz diffusion cell assay, the PNPS MNs demonstrated a high transdermal delivery amount of model drugs. Furthermore, with the assistance of MNs, PNPS easily penetrated across the stratum corneum and target ear skin DCs, activating the maturation and migration of immunocytes by increasing the expressions of CD40, CD80, CD86, and MHC II of skin DCs. Consequently, the matured DCs migrated to the auricular draining lymph nodes and increased the proportions of CD4+ T and CD8+ T cells. Thus, PNPS might be a promising biomaterial for transdermal drug delivery, with adjuvant potential.

Physiological Doses of Red Light Induce IL-4 Release in Cocultures between Human Keratinocytes and Immune Cells.

Phototherapy is routinely used for the treatment of various skin conditions and targeted therapy of superficial cancers. However, the molecular mechanisms behind their biological effects and the need for efficacy enhancing photosensitizers are not well addressed. Particularly, not much is known about the inherent effect of light from the visible spectrum on cytokine release and its downstream effects in keratinocytes and immune cells located in skin and therefore exposed to light. To address this, we delivered calibrated doses of well-defined light qualities (380 to 660 nm) to cocultures of human keratinocytes and macrophage/dendritic cells in the absence or presence of the commonly used photosensitizer 8-methoxypsoralen (8-MOP). The experiments identified IL-4 as a key effector cytokine released by this coculture model with need for 8-MOP in the UVA1 /blue (380 nm) and no requirement for photosensitizer in the red light spectrum (627 nm). 3D organotypic skin cultures treated with IL-4 showed thickening of the epidermal layer and delayed differentiation. However unlike IL-4 and UVA1 /blue light treatment, red light did not reduce the expression of keratinocyte differentiation markers or increase signs of photo-oxidative damage. This supports the application of isolated red light as a possible alternative for photo-immunotherapy without need for additional photosensitizers.

Effect of oral eicosapentaenoic acid on epidermal Langerhans cell numbers and PGD2 production in UVR-exposed human skin: a randomised controlled study.

Langerhans cells (LCs) are sentinels of skin's immune system, their loss from epidermis contributing to UVR suppression of cell-mediated immunity (CMI). Omega-3 polyunsaturated fatty acids show potential to reduce UVR suppression of CMI in mice and humans, potentially through modulation of LC migration. Our objectives were to examine whether eicosapentaenoic acid (EPA) ingestion influences UV-mediated effects on epidermal LC numbers and levels of immunomodulatory mediators including prostaglandin (PG)D2 , which is expressed by LC. In a double-blind randomised controlled study, healthy individuals took 5-g EPA-rich (n=40) or control (n=33) lipid for 12 weeks; UVR-exposed and unexposed skin samples were taken pre- and postsupplementation. Epidermal LC numbers were assessed by immunofluorescence for CD1a, and skin blister fluid PG and cytokines were quantified by LC-MS/MS and Luminex assay, respectively. Presupplementation, UVR reduced mean (SEM) LC number/mm2 from 913 (28) to 322 (40) (P<.001), and mean PGD2 level by 37% from 8.1 (11.6) to 5.1 (5.6) pg/µL; P<.001), while IL-8 level increased (P<.001). Despite confirmation of EPA bioavailability in red blood cells and skin in the active group, no between-group effect of EPA was found on UVR modulation of LC numbers, PGD2 or cytokine levels postsupplementation. Thus, no evidence was found for EPA reduction of photoimmunosuppression through an impact on epidermal LC numbers. Intriguingly, UVR exposure substantially reduced cutaneous PGD2 levels in humans, starkly contrasting with reported effects of UVR on other skin PG. Lowered PGD2 levels could reflect LC loss from the epidermis and/or altered dendritic cell activity and may be relevant for phototherapy of skin disease.

Effects of a traditional Chinese medicine, Longdanxiegan formula granule, on Toll-like receptor pathway in female guinea pigs with recurrent genital herpes.

OBJECTIVE: The aim of the present study was to investigate the effects of Longdanxiegan formula granule (LDXGFG), a Chinese traditional medicine on Toll-like receptor (TLR) pathway in recurrent genital herpes. MATERIALS AND METHODS: An experimental recurrent genital herpes model was constructed using herpes guinea pig model. The effect of LDXGFG on expression levels of TLR pathway genes were detected using real-time polymerase chain reaction. Furthermore, the dendritic cells and Langerhans cells were isolated and the TLR pathway genes of these cells were assayed after LDXGFG treatment. RESULTS: The result suggested two different expression patterns of TLR pathway genes in genital herpes and recurrent genital herpes, including upregulated genes and downregulated genes. TLR1, TLR4, TLR6, TLR7, TLR8, TLR9, and TLR10 showed a significant decrease while, TLR2, TLR3, and TLR5 increased in genital herpes and recurrent genital herpes guinea pigs. Meanwhile, the downregulated genes in genital herpes and recurrent genital herpes were stimulated by LDXGFG. By contrast, the upregulated genes decreased significantly after LDXGFG treatment. In both dendritic cells and Langerhans cells, the TLR pathway genes exhibited same pattern: the LDXGFG corrected the abnormal expression of TLR pathway genes. CONCLUSION: The present results suggest that LDXGFG is an alternative, inexpensive, and lasting-effect medicine for herpes simplex virus 2 infection.

Calcipotriol and betamethasone dipropionate exert additive inhibitory effects on the cytokine expression of inflammatory dendritic cell-Th17 cell axis in psoriasis.

BACKGROUND: Psoriasis vulgaris is characterised by epidermal hyper-proliferation and infiltration of immune cells including dendritic cells (DCs) and T cells. The inflammation is driven by a complex interplay between immune and skin cells involving interleukin (IL)-17A, IL-23 and TNF-α as key drivers. The calcipotriol/betamethasone dipropionate two-compound fixed combination product is widely used for topical treatment of psoriasis. However, the mechanism behind its high efficacy has not been elucidated in detail. OBJECTIVE: Here, we investigated and compared the immune modulatory effects of betamethasone, calcipotriol and the combination in ex vivo cultures of psoriatic skin and in vitro cultures of primary human cells that recapitulate key cellular activities of psoriatic inflammation. METHOD: The immune modulatory effect of the treatments on psoriatic skin and on in vitro differentiated Th1/Th17 cells, Tc1/Tc17 cells, monocyte-derived inflammatory dendritic cells and primary keratinocytes was assessed by a panel of inflammatory and phenotypic related transcription factors and cytokines. The expression was evaluated by both gene and protein analysis. RESULTS: Compared to vehicle control or mono-treatments, the effect of calcipotriol/betamethasone combination was significantly better in inhibiting the secretion of IL-17A and TNF-α in psoriatic skin. Additionally, the two components showed additive inhibitory effects on secretion of IL-23 and TNF-α by DCs, of IL-17A and TNF-α by both CD4(+) and CD8(+) T cells and reduced inflammatory responses in Th17-stimulated keratinocytes. Furthermore, calcipotriol was found to enhance IL-10 secretion in psoriatic skin and in human T cells, to induce secretion of type 2 cytokines by T cells and, lastly, to significantly modulate the differentiation of DCs and T cells. CONCLUSIONS: In summary, we demonstrate a unique and supplementary immune modulatory effect of calcipotriol/betamethasone combination on TNF-α and IL-23/Th17 immune axis, supporting the superior clinical efficacy of the combination product compared to the respective mono-treatments in psoriasis patients.

Immunological changes in the intestines and skin after senna administration.

CONTEXT: It has been reported that chronic sennoside use is associated with the development of melanosis coli, colonic adenoma, and/or carcinomas. OBJECTIVES: In this study, we investigated the immunological changes in the colon and skin after the administration of senna. MATERIALS AND METHODS: In this study, we investigated the colon and epidermis of C57/BL6j mice after a single administration of 10 mg/kg of senna [Cassia angustifolia (Caesalpiniaceae); 3, 6, 12, and 24 h after administration] and after repeated once per week administrations (on days 3, 5, 7, 14, and 21 of administration). The LD50 and ED50 of senna used in this experiment were 165 mg/kg and 13 g/kg, respectively. RESULTS: We demonstrated that the DOPA-positive cells in the colon increased at 12 h after single administration and were further increased from at 5-28 d after repeated administration. We also studied the physiological changes of the small intestine using the charcoal meal test. We found that there was a tendency for peristalsis to be inhibited after repeated senna administration. In the epidermis, we investigated the number of Langerhans cells, because they are important immune cells of the skin. The number of these cells decreased, especially after repeated administration. DISCUSSION AND CONCLUSION: The present findings suggested that it is necessary to pay attention to not only the intestine but also the skin, during long-term senna treatment.

Assessment of Augmented Immune Surveillance and Tumor Cell Death by Cytoplasmic Stabilization of p53 as a Chemopreventive Strategy of 3 Promising Medicinal Herbs in Murine 2-Stage Skin Carcinogenesis.

Cancer is the final outcome of a plethora of events. Targeting the proliferation or inducing programmed cell death in a proliferating population is a major standpoint in the cancer therapy. However, proliferation is regulated by several cellular and immunologic processes. This study reports the inhibition of proliferation by augmenting immune surveillance, silencing acute inflammation, and inducing p53-mediated apoptosis of skin cancer by 3 promising medicinal extracts. We used the well-characterized model for experimental skin carcinogenesis in mice for 32 weeks to study the chemopreventive effect of the methanolic extracts of Trigonella foenumgraecum, Eclipta alba, and Calendula officinalis. All 3 extracts reduced the number, incidence, and multiplicity of tumors, which was confirmed by the pathologic studies that showed regressed tumors. There was a significant reduction in the PCNA+ nuclei in all treatment groups 32 weeks after the initiation. Mechanistic studies revealed that proliferative population in tumors is diminished by the restoration of the endogenous antioxidant defense, inhibition of the stress-related signal-transducing element NFκB, reduction of inflammation, enhancement of immunosurveillance of the genetically mutated cells, along with silencing of the cell cycle progression signals. Finally, all 3 medicinal extracts induced stable expression of p53 within the tumors, confirmed by the CFDA-Cy3 apoptosis assay. Results of our study confirm that these extracts not only limit the rate of proliferation by inhibition of the processes integral to cancer development but also induce stable cytoplasmic expression of p53-mediated apoptosis, leading to fewer and regressed tumors in mice.

Skin penetration of topically applied white mustard extract and its effects on epidermal Langerhans cells and cytokines.

White mustard (Sinapis alba L.), a traditional Chinese medicine, is widely used in China for clinical prevention and treatment of the common winter diseases of asthma and bronchitis by percutaneous administration in the summer. The present study is to investigate the skin penetration behavior of white mustard extract to elucidate the possible mechanism underlying its immune regulation activity. The principle active compound of the extract, sinapine thiocyanate (ST), was used as a marker. The skin penetration of ST in white mustard extract was examined in vitro and in vivo. In vitro study on excised guinea pig hairless skin using Franz diffusion cell revealed ST can permeate through the skin and also accumulate in the skin. In vivo study was carried out on the guinea pig hairless skin for 24 h, and then skin was excised for frozen section, ST from the sections were extracted to quantify the amount of drug in different skin layers. The detailed distribution of ST showed that it accumulated in the epidermis, especially in the stratum corneum. After treatment with white mustard extract for 24h, the skin was stained with ATPase, and the morphometric parameters of epidermal LCs were compared to the untreated control through image-analysis system. A statistically significant reduction in LC density and increase in shape factor were observed. Cytokines related to LCs migration including interleukin 1ß (IL-1ß) and tumor necrosis factor α (TNF-α) were also measured after white mustard extract treated at different time points. Compared to the untreated group, white mustard extract significantly enhanced the release of IL-1ß and TNFα. The morphometric changes of LCs and the local cytokine release after topical white mustard treatment may explain the activity of the white mustard extract against asthma and bronchitis.

Modulation of CD86 expression in skin dendritic cells does not always correlate with changes in DC motility, migration and allostimulatory functions.

CD86 expression is a well-known activation marker of dendritic cells (DC). In this study, we compared the level of CD86 expression in monocyte-derived skin DC with their motility, migratory abilities and allostimulatory capabilities. We show that motility and migration could be uncoupled from activation and that the immune response-modulating effects of certain compounds may correlate with down-regulation of CD86 expression rather than with effects on motility and migration.

Evaluation of the phototoxic potential of plants used in oriental medicine.

AIM OF THE STUDY: Phototoxicity can be either harmful or beneficial. Yet the phototoxicity of oriental medicinal plants is an understudied area. The purpose of this study is to fill in this gap. MATERIALS AND METHODS: The phototoxic potential of oriental medicinal plants was examined in vitro using photohemolysis and the Candida albicans test. Seventeen medicinal plants [Acorus gramineus (ACG), Panax ginseng C.A. (PAG), Platycodon grandiflorum (PLG), Aractylodes japonica (ATJ), Xanthium strumarium (XAS), Dioscorea batatas (DIB), Anemarrhena asphodeloides (ANA), Polygonatum sibiricum Red (PSR), Cocculus trilobus (COT), Ficus carica (FIC), Chelidonium majus var. asiaticum (CMA), Pulsatilla koreana (PUK), Agrimonia pilosa (AGP), Zanthoxylum schinifolium (ZAS), Angelica gigas (ANG), Ledebouriella seseloides (LES), and Cnidium officinale (CNO)] were selected because they showed strong fluorescence in one of our previous studies of 62 plants. We further evaluated in vivo phototoxicity in mice. 0.75 mL/kg of seed oil for Xanthium strumarium (XAS, ), or 1.25 mL/kg of extracted solutions of Atractylodes japonica (ATJ, ), Chelidonium majus var. asiaticum (CMA, ), Zanthoxylum schinifolium (ZAS, ), and Ledebouriella seseloides (LES, ) were given once, and evaluated for sunburn edema, formation of sunburn cell, decrease of epidermal Langerhans cells and local suppression of contact hypersensitivity by UVA irradiation. RESULTS: Sixteen out of the 17 plants tested except COT showed significant photohemolysis, and 5 of those exhibited phototoxic killing of Candida albicans. The phototoxicity of oriental medicines using those 5 plants was then studied in mice. The 5 plants increased sunburn edema and formation of sunburn cell, and suppressed immune responses locally by decreasing epidermal Langerhans cells and contact hypersensitivity by UVA irradiation. CONCLUSIONS: More than a quarter of oriental medicinal plants can be phototoxic, and strong fluorescence measured by absorption and fluorescence spectra can be an easier way to screen for phototoxicity. On the other hand, the phototoxicity of the plants may also be used therapeutically. Further studies regarding the phototoxicity of active components extracted from both live and dried oriental medicinal plants are necessary.

Inhibitory effects of Schefflera leucantha extract on production of allergic mediators by Langerhans cells and mast cells.

BACKGROUND: Schefflera leucantha Viguier is used as a traditional medicine in Thailand and China to relieve chronic cough and asthma. However, little is known about its anti-allergic effects. OBJECTIVE: This study was designed to investigate the effects of S leucantha ethanol extract (SLEE) on chemokine production by epidermal Langerhans cells (LCs) stimulated with peptidoglycan (PEG) from Staphylococcus aureus and histamine release from mast cells. METHODS: LCs were purified from murine epidermal cells using the panning method with anti-IA(d) monoclonal antibody. Chemokine production by LCs was investigated by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA). Mast cells for histamine release assay were induced by long-term culture of mouse spleen cells. Histamine release from these mast cells was measured by a competitive ELISA. RESULTS: Production of the eosinophil chemoattractant CCL5 and the type 2 T helper (TH2)-associated chemokine CCL17 from PEG-stimulated LCs was significantly inhibited by SLEE. Furthermore, SLEE significantly decreased the release of histamine from mast cells by IgE-mediated degranulation. CONCLUSION: These results suggest that S leucantha may offer a new therapeutic approach for the control of atopic dermatitis associated with S aureus colonization through inhibition of the production of allergic mediators.

Non-sunscreen photoprotection: antioxidants add value to a sunscreen.

The association between ultraviolet radiation (UVR) exposure and both skin cancer and photo-aging is well documented. In addition to the conventional organic-chemical and physical-mineral type sunscreens, other non-sunscreen protective strategies have been developed. These include topically applied botanical extracts and other antioxidants as well as topical DNA repair enzymes. Standard terms of photoprotection such as sun protection factor (SPF) do not accurately reflect the photoprotection benefits of these materials. For example, in spite of minimal SPF, tea extract containing polyphenols such as (-)-epigallocatechin-3-gallate (EGCG) has been shown to protect against UV-induced DNA damage and immune suppression, in part through its ability to reduce oxidative stress and inhibit NF-kB. The addition of botanical antioxidants and vitamins C and E to a broad-spectrum sunscreen may further decrease UV-induced damage compared with sunscreen alone. These agents have been shown to enhance protection against UV-induced epidermal thickening, overexpression of MMP-1and MMP-9, and depletion of CD1a(+) Langerhans cells. Non-sunscreen materials such as botanical extracts, antioxidants, and DNA repair enzymes can contribute value when applied topically to human skin in vivo.Journal of Investigative Dermatology Symposium Proceedings (2009) 14, 56-59; doi:10.1038/jidsymp.2009.14.

Topical application of green and white tea extracts provides protection from solar-simulated ultraviolet light in human skin.

BACKGROUND: Tea polyphenols have been found to exert beneficial effects on the skin via their antioxidant properties. AIMS: We sought to determine whether topical application of green tea or white tea extracts would prevent simulated solar radiation-induced oxidative damages to DNA and Langerhans cells that may lead to immune suppression and carcinogenesis. METHODS: Skin samples were analysed from volunteers or skin explants treated with white tea or green tea after UV irradiation. In another group of patients, the in vivo immune protective effects of green and white tea were evaluated using contact hypersensitivity to dinitrochlorobenzene. RESULTS: Topical application of green and white tea offered protection against detrimental effects of UV on cutaneous immunity. Such protection is not because of direct UV absorption or sunscreen effects as both products showed a sun protection factor of 1. There was no significant difference in the levels of protection afforded by the two agents. Hence, both green tea and white tea are potential photoprotective agents that may be used in conjunction with established methods of sun protection.

Differential effects of doses and forms of dietary selenium on immune cell numbers in the skin of ultraviolet-irradiated and unirradiated mice.

The effect of three different doses of dietary L-selenomethionine (SM) and sodium selenite (SS) on skin selenium (Se) content, glutathione peroxidase (GPx) activity, Langerhans cell (LC) and mast cell numbers in ultraviolet radiation-B (UVB)-irradiated and unirradiated C3H/HeN mice was determined. After weaning, groups of mice were given Se-deficient, Se-adequate, or Se-high diets. Six weeks later, some animals in each group were exposed to a single UVB dose (acute), while others were exposed three times weekly for the following 40 weeks (chronic). The skin Se content and GPx activity increased in all the Se-supplemented groups, and the latter was not altered by UVB exposure. Generally, the Se-containing diets caused an increase in LC numbers at 6 weeks and a further rise at 40 weeks, but did not prevent the loss induced by acute or chronic UVB radiation. Skin mast cell numbers were highest in animals fed the Se-deficient diet after 6 and 40 weeks. Acute and chronic UVB radiation decreased the mast cell number and dietary Se did not prevent the reduction. While the present study shows that Se plays an important role in governing the number of LCs and mast cells in the skin, no protective effect against the immunomodulating properties of UVB radiation on these cell types was observed. However, this conclusion may only apply to the experimental conditions chosen, and additional studies at different Se dosages and reduced intensities of chronic UVB exposure are required to confirm the results.

Polypodium leucotomos extract inhibits glutathione oxidation and prevents Langerhans cell depletion induced by UVB/UVA radiation in a hairless rat model.

In this report, we have addressed the effect of oral administration of a hydrophilic extract of the fern Polypodium leucotomos (PL) on the deleterious effects of ultraviolet radiation (UVR) on the levels of epidermal and plasmatic antioxidants in hairless rats. We have found that pretreatment with PL effectively reduced glutathione oxidation in both blood and epidermis, suggesting a potent systemic antioxidant effect. In addition, PL inhibited UVR-mediated Langerhans cell (LC) depletion. Our results demonstrate the efficacy of PL as an oral antioxidant and photoimmunoprotective agent and support its employment as a complement to topical sunscreens.

Immunosuppressive effects of photodynamic therapy by topical aminolevulinic acid.

Photodynamic therapy (PDT) has been used for inflammatory skin disorders as well as superficial skin cancers such as solar keratosis and Bowen's disease. Whether PDT with topical application of aminolevulinic acid (ALA) and exposure to visible light has a similar immunosuppressive action to ultraviolet phototherapy was investigated using a murine contact hypersensitivity (CHS) model. The number of epidermal Langerhans cells (LC) was decreased with their morphological changes 1 day after PDT with the minimal level at 5 days and gradual recovery thereafter. Conversely, the number of CD11c(+) I-A(+) cells was significantly increased in the draining lymph nodes after PDT. This suggests that LC moved from PDT-treated skin, resulting in the decrement of epidermal LC and migration to lymph nodes. CHS response to DNFB applied on the PDT-treated skin with 20% ALA and 40 J/cm(2) visible light was significantly suppressed (local immunosuppression). When mice were treated with 80 J/cm(2) of PDT, CHS response to the antigen applied on untreated distant skin was also significantly suppressed (systemic immunosuppression). The locally or systemically immunosuppressed mice by PDT were attempted to sensitize again with DNFB on non-treated skin, but elicitation responses were significantly suppressed. However, these mice were able to be sensitized with another hapten, oxasolone. Thus, a hapten-specific immunological unresponsiveness (tolerance) was induced in mice by topical ALA-PDT. These findings suggest that PDT has a potential immunological contribution to clinical efficacy for inflammatory diseases identical to ultraviolet phototherapies.

Effect of dietary supplementation with vitamin E and stocking density on macrophage recruitment and giant cell formation in the teleost fish, Piaractus mesopotamicus.

The effect of dietary supplementation with 0, 100 and 450 mg of vitamin E (DL-alpha tocopheryl acetate)/kg of a dry diet on the kinetics of macrophage recruitment and giant cell formation in the pacu, maintained at different stocking densities (5 kg/m(3) and 20 kg/m(3)), was investigated by insertion of round glass coverslips into the subcutaneous connective tissue. After a feeding period of 18 weeks, the coverslips were implanted and later removed for examination at 2, 7 and 15 days post-implantation. Fish fed diets supplemented with 450 mg of vitamin E showed an increase (P<0.05) in the accumulation of macrophages, foreign body giant cells and Langhans type cells. The kinetics of macrophage recruitment and giant cell formation on the glass coverslips appeared to be strongly influenced by vitamin E supplementation, since fish fed a basal diet and held at high stocking densities showed low numbers of adhering cells on the coverslips, and high concentrations of plasma corticosteroids. On the other hand, fish given a diet supplemented with 450 mg of vitamin E did not show a similar difference in plasma cortisol concentrations related to stocking density. The effect of cortisol concentrations on carbohydrate metabolism, analysed by assessment of plasma glycaemia, was not clear. Blood glucose concentrations did not vary substantially with the different treatments examined. These results suggest that vitamin E may contribute to the efficiency of the fish's inflammatory response by increasing macrophage recruitment and giant cell formation in the foreign body granulomatous reaction. Vitamin E appeared to act on the stress response of pacus by preventing a stress-related immunosuppression.

Augmentation of cutaneous immune responses by ATP gamma S: purinergic agonists define a novel class of immunologic adjuvants.

Extracellular nucleotides activate ligand-gated P2XR ion channels and G protein-coupled P2YRs. In this study we report that intradermal administration of ATPgammaS, a hydrolysis-resistant P2 agonist, results in an enhanced contact hypersensitivity response in mice. Furthermore, ATPgammaS enhanced the induction of delayed-type hypersensitivity to a model tumor vaccine in mice and enhanced the Ag-presenting function of Langerhans cells (LCs) in vitro. Exposure of a LC-like cell line to ATPgammaS in the presence of LPS and GM-CSF augmented the induction of I-A, CD80, CD86, IL-1beta, and IL-12 p40 while inhibiting the expression of IL-10, suggesting that the immunostimulatory activities of purinergic agonists in the skin are mediated at least in part by P2Rs on APCs. In this regard, an LC-like cell line was found to express mRNA for P2X(1), P2X(7), P2Y(1), P2Y(2), P2Y(4), P2Y(9), and P2Y(11) receptors. We suggest that ATP, when released after trauma or infection, may act as an endogenous adjuvant to enhance the immune response, and that P2 agonists may augment the efficacy of vaccines.

Novel protein kinase C and matrix metalloproteinase inhibitors of vegetable origin as potential modulators of Langerhans cell migration following hapten-induced sensitization.

BACKGROUND: Migration and maturation of epidermal dendritic cells, the Langerhans cells (LC), are central events in the initiation of the cutaneous immune response. LC migration from skin to draining lymph nodes is regarded as an indispensable step for the early phase of antigen-specific sensitization. Among the several agents which influence the ability of LC to migrate, previous studies have revealed that matrix metalloproteinases (MMPs) and protein kinase C (PKC) contribute to promoting LC migration. In this work, we studied the effect of two recently developed PKC and MMPs inhibitors of vegetable origin on the migration of in vitro activated LC. METHODS: The migratory capacity of epidermal and in vitro generated LC was assessed using a reconstituted basement membrane assay (Matrigel), mimicking the prerequisite passage through the dermal-epidermal basement membrane on the way to the lymph nodes. RESULTS: Contact with chemical allergens, Bandrowski's base or 2,4-dinitrobenzenesulfonic acid (DNBS), triggered migration. In the presence of PKC inhibitors, D-erythro-sphingosine and OX100, or an inhibitor of MMPs, LU105, allergen-induced migration of LC was strongly decreased. The association between OX100 and LU105 was more efficient in modulating the migration of activated LC compared to each molecule tested separately. CONCLUSIONS: These results showed that PKC and MMPs inhibitors act in synergy to inhibit the migration of activated epidermal dendritic cells in vitro. They underscore the role of PKC and MMPs inhibitors and suggest they may be of relevance for therapeutically regulating epidermal dendritic cell migration in inflammatory dermatoses.