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Find video protocols related to scientific articles indexed in Pubmed.
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Palmoplantar keratosis in oculodentodigital dysplasia with a GJA1 point mutation out of the C-terminal region of connexin 43.
J. Dermatol.
PUBLISHED: 08-29-2014
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Gap junction proteins are composed of 21 genes of the connexin (Cx) family. They play important roles in cell-cell contact by exchange of small molecules through hemichannels. Hence, mutations of Cx family genes affect various tissues of a body. The mutation of the GJA1 gene, which codes Cx43, causes oculodentodigital dysplasia (ODDD), commonly in an autosomal dominant manner with phenotypic variability. It has been believed that gene mutations causing truncation of the Cx43 C-terminus is necessary and sufficient for palmoplantar keratosis (PPK) development in ODDD patients. Here, we report a case of an ODDD patient developing PPK with a GJA1 gene mutation (c.412G>A/p.Gly138Ser), which was previously reported in a case of ODDD without PPK and expected not to result in C-terminal truncation of Cx43. This case suggests not only C-terminal truncation, but also that a point mutation in the cytoplasmic region of Cx43 can cause PPK in ODDD patients.
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Classification of inflammatory skin diseases: A proposal based on the disorders of the three-layered defense systems, barrier, innate immunity and acquired immunity.
J. Dermatol. Sci.
PUBLISHED: 08-12-2014
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The host defense system of the skin is composed of (1) a barrier, (2) innate immunity, and (3) acquired immunity. Inflammatory skin diseases can be classified into one of the disorders of these layers of the defense system, unless there is an ordinary response to specific infectious agents or internal/external injury. Any inflammatory skin disease partly simulates the response to real infections or dangers. Disorders of acquired immunity can be classified into (1) immunodeficiency, (2) immunohyperactivity (allergy), and (3) qualitative disorder (autoimmunity). Disorders of innate immunity can be classified into (1) innate immunodeficiency, (2) innate immunohyperactivity (general or local autoinflammation), and (3) qualitative disorder (general or local innate autoimmunity). The barrier of the skin is composed of (1) the physical barrier and (2) the chemical barrier. Several diseases, such as atopic dermatitis, are attributed to the disorder of these components of the barrier. Here, we propose an algorithm to classify the pathology of inflammatory skin diseases by means of what disorder in the specific layer of the host defense system is truly responsible.
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The panoply of ??T cells in the skin.
J. Dermatol. Sci.
PUBLISHED: 08-12-2014
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Skin protects body from continual attack by microbial pathogens and environmental factors. Such barrier function of skin is achieved by multiple components including immune system, which is mainly regulated by lymphocytes. T lymphocytes (T cells) that express T cell receptor (TCR) ? and ? chains (??T cells) control the strength and the type of immune response. CD4T cell population consists of helper T (Th) cell-subsets and immunosuppressive regulatory T (Treg) cells. Th1 cells produce IFN-? and protect against intracellular pathogens. Th2 cells produce IL-4 family cytokines and participate in allergic skin diseases, including atopic dermatitis (AD). Th17 cells secrete IL-17, recruit granulocytes to fight against extracellular microorganisms, and play a role in psoriasis and AD. Th22 cells produce IL-22 that activates epithelial cells and mediates acanthosis in psoriasis and AD. On the other hand, Foxp3+ Treg cells attenuate immune responses partly via TGF-? or IL-10. Tissue resident memory T (Trm) cells in the skin-most of which are epidermal CD8T cells-constitute the first line of the defense against repeated infections. CD8 T cells are also engaged in psoriasis, lichen planus, and drug eruptions. Skin harbors innate-like ??T cells such as natural killer T (NKT) cells as well, whose function is not fully revealed. Understanding these ??T cells helps to comprehend skin diseases.
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Tracking and quantification of dendritic cell migration and antigen trafficking between the skin and lymph nodes.
Sci Rep
PUBLISHED: 08-12-2014
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Skin-derived dendritic cells (DCs) play a crucial role in the maintenance of immune homeostasis due to their role in antigen trafficking from the skin to the draining lymph nodes (dLNs). To quantify the spatiotemporal regulation of skin-derived DCs in vivo, we generated knock-in mice expressing the photoconvertible fluorescent protein KikGR. By exposing the skin or dLN of these mice to violet light, we were able to label and track the migration and turnover of endogenous skin-derived DCs. Langerhans cells and CD103(+)DCs, including Langerin(+)CD103(+)dermal DCs (DDCs), remained in the dLN for 4-4.5 days after migration from the skin, while CD103(-)DDCs persisted for only two days. Application of a skin irritant (chemical stress) induced a transient >10-fold increase in CD103(-)DDC migration from the skin to the dLN. Tape stripping (mechanical injury) induced a long-lasting four-fold increase in CD103(-)DDC migration to the dLN and accelerated the trafficking of exogenous protein antigens by these cells. Both stresses increased the turnover of CD103(-)DDCs within the dLN, causing these cells to die within one day of arrival. Therefore, CD103(-)DDCs act as sentinels against skin invasion that respond with increased cellular migration and antigen trafficking from the skin to the dLNs.
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Commensal bacteria and cutaneous immunity.
Semin Immunopathol
PUBLISHED: 07-13-2014
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The skin is the human body's largest organ and is home to a diverse and complex variety of innate and adaptive immune functions that protect against pathogenic invasion. Recent studies have demonstrated that cutaneous commensal bacteria modulated the host immune system. For example, Staphylococcus epidermidis, a skin commensal bacterium, has been demonstrated to induce cutaneous interferon (IFN)-?- and interleukin (IL)-17A-producing T cells. In addition, cutaneous microbiota changes occur in the chronic inflammatory skin disorders, such as atopic dermatitis, and may influence the activity of skin diseases. In this article, we will review the recent findings related to the interactions of the commensal bacteria with skin homeostasis and discuss the role of the dysbiosis of these bacteria in the pathogenesis of skin diseases.
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Perivascular leukocyte clusters are essential for efficient activation of effector T cells in the skin.
Nat. Immunol.
PUBLISHED: 07-07-2014
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It remains largely unclear how antigen-presenting cells (APCs) encounter effector or memory T cells efficiently in the periphery. Here we used a mouse contact hypersensitivity (CHS) model to show that upon epicutaneous antigen challenge, dendritic cells (DCs) formed clusters with effector T cells in dermal perivascular areas to promote in situ proliferation and activation of skin T cells in a manner dependent on antigen and the integrin LFA-1. We found that DCs accumulated in perivascular areas and that DC clustering was abrogated by depletion of macrophages. Treatment with interleukin 1? (IL-1?) induced production of the chemokine CXCL2 by dermal macrophages, and DC clustering was suppressed by blockade of either the receptor for IL-1 (IL-1R) or the receptor for CXCL2 (CXCR2). Our findings suggest that the dermal leukocyte cluster is an essential structure for elicitating acquired cutaneous immunity.
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Intractable prurigo nodularis successfully treated with combination therapy with a newly developed excimer laser and topical steroids.
Dermatol. Online J.
PUBLISHED: 06-13-2014
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Prurigo nodularis (PN) is an eruption of lichenified or excoriated nodules related to intractable pruritus. A few reports have shown that a 308-nm excimer lamp/laser (EL) is effective for intractable PN. Herein, we report on two cases of intractable prurigo nodularis successfully treated with a new EL equipped with a filter to cut wavelengths shorter than 297 nm. Because this newly developed EL yields a therapeutic effect with low cumulative dosages of UV and a lower risk of DNA damage, it can be a new treatment option for intractable PN.
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The role of basophils and proallergic cytokines, TSLP and IL-33, in cutaneously sensitized food allergy.
Int. Immunol.
PUBLISHED: 05-22-2014
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Cutaneous sensitization with a food antigen before its consumption elicits the development of food allergy. Here, we report the site- and stage-dependent roles of basophils and proallergic cytokines, thymic stromal lymphopoietin (TSLP) and IL-33, in a mouse model of food allergy initially sensitized cutaneously with the food antigen. Mice were epicutaneously sensitized with the food antigen ovalbumin (OVA) followed by oral challenge with OVA. Epicutaneously sensitized mice produced OVA-specific IgE and developed IgE-dependent anaphylaxis after oral challenge. Basophil-depleted or TSLP-receptor-deficient mice did not produce OVA-specific IgE and were protected from oral challenge-induced anaphylaxis. IL-33-deficient mice produced normal levels of OVA-specific IgE. However, IL-33-deficient mice and mice treated with recombinant soluble IL-33 receptor were protected from anaphylaxis. Thus, basophils and TSLP have pivotal roles in Th2 development in the skin during the sensitization phase of food allergy. In contrast, while IL-33 is dispensable for promoting cutaneous antigen sensitization, the cytokine is essential for inducing IgE-dependent anaphylaxis in the gut.
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In vivo imaging reveals PKA regulation of ERK activity during neutrophil recruitment to inflamed intestines.
J. Exp. Med.
PUBLISHED: 05-19-2014
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Many chemical mediators regulate neutrophil recruitment to inflammatory sites. Although the actions of each chemical mediator have been demonstrated with neutrophils in vitro, how such chemical mediators act cooperatively or counteractively in vivo remains largely unknown. Here, by in vivo two-photon excitation microscopy with transgenic mice expressing biosensors based on Förster resonance energy transfer, we time-lapse-imaged the activities of extracellular signal-regulated kinase (ERK) and protein kinase A (PKA) in neutrophils in inflamed intestinal tissue. ERK activity in neutrophils rapidly increased during spreading on the endothelial cells and showed positive correlation with the migration velocity on endothelial cells or in interstitial tissue. Meanwhile, in the neutrophils migrating in the interstitial tissue, high PKA activity correlated negatively with migration velocity. In contradiction to previous in vitro studies that showed ERK activation by prostaglandin E2 (PGE2) engagement with prostaglandin receptor EP4, intravenous administration of EP4 agonist activated PKA, inhibited ERK, and suppressed migration of neutrophils. The opposite results were obtained using nonsteroidal antiinflammatory drugs (NSAIDs). Therefore, NSAID-induced enteritis may be caused at least partially by the inhibition of EP4 receptor signaling of neutrophils. Our results demonstrate that ERK positively regulates the neutrophil recruitment cascade by promoting adhesion and migration steps.
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12-Hydroxyheptadecatrienoic acid promotes epidermal wound healing by accelerating keratinocyte migration via the BLT2 receptor.
J. Exp. Med.
PUBLISHED: 05-12-2014
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Leukotriene B4 (LTB4) receptor type 2 (BLT2) is a G protein-coupled receptor (GPCR) for 12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid (12-HHT) and LTB4. Despite the well-defined proinflammatory roles of BLT1, the in vivo functions of BLT2 remain elusive. As mouse BLT2 is highly expressed in epidermal keratinocytes, we investigated the role of the 12-HHT/BLT2 axis in skin wound healing processes. 12-HHT accumulated in the wound fluid in mice, and BLT2-deficient mice exhibited impaired re-epithelialization and delayed wound closure after skin punching. Aspirin administration reduced 12-HHT production and resulted in delayed wound closure in wild-type mice, which was abrogated in BLT2-deficient mice. In vitro scratch assay using primary keratinocytes and a keratinocyte cell line also showed that the 12-HHT/BLT2 axis accelerated wound closure through the production of tumor necrosis factor ? (TNF) and matrix metalloproteinases (MMPs). A synthetic BLT2 agonist accelerated wound closure in cultured cells as well as in C57BL/6J and diabetic mice. These results identify a novel mechanism underlying the action of the 12-HHT/BLT2 axis in epidermal keratinocytes and accordingly suggest the use of BLT2 agonists as therapeutic agents to accelerate wound healing, particularly for intractable wounds, such as diabetic ulcers.
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An ITAM-Syk-CARD9 signalling axis triggers contact hypersensitivity by stimulating IL-1 production in dendritic cells.
Nat Commun
PUBLISHED: 03-28-2014
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A variety of reactive organic compounds, called haptens, can cause allergic contact dermatitis. However, the innate immune mechanisms by which haptens stimulate dendritic cells (DCs) to sensitize T cells remain unclear. Here we show that the coupling of ITAM-Syk-CARD9 signalling to interleukin-1 (IL-1) secretion in DCs is crucial for allergic sensitization to haptens. Both MyD88 and Caspase recruitment domain-containing protein 9 (CARD9) signalling are required for contact hypersensitivity (CHS). Naïve T cells require signals received through IL-1R1-MyD88 for effector differentiation, whereas DCs require CARD9 and spleen tyrosine kinase (Syk) signalling for hapten-induced IL-1?/? secretion and their ability to prime T cells. DC-specific deletion of CARD9, DAP12, Syk or NLRP3, but not MyD88, is sufficient to abolish CHS. All tested haptens, but not irritants, can induce Syk activation, leading to both the CARD9/BCL10-dependent pro-IL-1 synthesis (signal1) and reactive oxygen species-mediated NLRP3 inflammasome activation (signal2), required for IL-1 secretion. These data unveil an innate immune mechanism crucial for allergic contact sensitization to chemical compounds.
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Natural killer T cells are essential for the development of contact hypersensitivity in BALB/c mice.
J. Invest. Dermatol.
PUBLISHED: 03-25-2014
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Contact hypersensitivity (CHS) has been widely used to study cutaneous immune responses, as a prototype of delayed-type hypersensitivity. Although natural killer T (NKT) cells have been assumed to have an important role in CHS, their role is controversial. Here, we report the role of NKT cells in the sensitization phase of CHS, by promoting the survival and maturation of dendritic cells (DCs) in the draining lymph nodes (LNs). The CHS response was attenuated with Cd1d1(-/-) and Traj18(-/-) BALB/c mice in which NKT cells were absent. In the draining LNs, the number of effector T cells and cytokine production were significantly reduced with NKT cell-deficient mice. NKT cells activated and colocalized with DCs in the draining LNs after sensitization. The number of migrated and mature DCs was reduced in NKT cell-deficient mice 72?hours after FITC application. In in vitro experiments, activated NKT cells enhanced bone marrow-derived DC (BMDC) survivability via tumor necrosis factor (TNF) production from BMDCs. In addition, TNF production from BMDCs was partially suppressed by the neutralizing anti-CD54 or CD154 antibodies. Our data demonstrate that DC-NKT interaction has a pivotal role in the sensitization phase of CHS.
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Basophils regulate the recruitment of eosinophils in a murine model of irritant contact dermatitis.
J. Allergy Clin. Immunol.
PUBLISHED: 02-10-2014
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Although eosinophils have been detected in several human skin diseases in the vicinity of basophils, how eosinophils infiltrate the skin and the role of eosinophils in the development of skin inflammation have yet to be examined.
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Intravital multiphoton imaging of cutaneous immune responses.
J. Invest. Dermatol.
PUBLISHED: 02-06-2014
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Varieties of immune cells orchestrate cutaneous immune responses. To capture such dynamic phenomena, intravital imaging is an important technique and it may provide substantial information that is not available using the conventional histological analysis. Multiphoton microscopy enables the direct, three-dimensional, and minimally invasive imaging of biological samples with high spatio-temporal resolution, and it has now become the leading method for in vivo imaging studies. Using fluorescent dyes and transgenic reporter animals, not only skin structures but also cell- and humor-mediated cutaneous immune responses have been visualized.
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Leukotrienes as key mediators and amplifiers in allergic inflammation: insights from the bench and clinic.
Exp. Dermatol.
PUBLISHED: 01-31-2014
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Lipid mediators, such as leukotrienes (LTs) and prostaglandins (PGs), have a variety of physiological roles through their respective receptors. They are involved in both the maintenance of homoeostasis and the pathobiology of many diseases. Recent developments in relevant gene-targeted animals and receptor-selective compounds have significantly advanced our understanding of the role of lipid mediators in the immune system. In the Viewpoint entitled, 'Leukotrienes orchestrating allergic skin inflammation', Dr Sadik and colleagues provide a comprehensive overview of the current progress on the new roles of LTs in cutaneous allergy and sketch important future research avenues.
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The enzyme Cyp26b1 mediates inhibition of mast cell activation by fibroblasts to maintain skin-barrier homeostasis.
Immunity
PUBLISHED: 01-15-2014
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Mast cells (MCs) mature locally, thus possessing tissue-dependent phenotypes for their critical roles in both protective immunity against pathogens and the development of allergy or inflammation. We previously reported that MCs highly express P2X7, a receptor for extracellular ATP, in the colon but not in the skin. The ATP-P2X7 pathway induces MC activation and consequently exacerbates the inflammation. Here, we identified the mechanisms by which P2X7 expression on MCs is reduced by fibroblasts in the skin, but not in the other tissues. The retinoic-acid-degrading enzyme Cyp26b1 is highly expressed in skin fibroblasts, and its inhibition resulted in the upregulation of P2X7 on MCs. We also noted the increased expression of P2X7 on skin MCs and consequent P2X7- and MC-dependent dermatitis (so-called retinoid dermatitis) in the presence of excessive amounts of retinoic acid. These results demonstrate a unique skin-barrier homeostatic network operating through Cyp26b1-mediated inhibition of ATP-dependent MC activation by fibroblasts.
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IL-23 from Langerhans cells is required for the development of imiquimod-induced psoriasis-like dermatitis by induction of IL-17A-producing ?? T cells.
J. Invest. Dermatol.
PUBLISHED: 01-07-2014
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Psoriasis is a common chronic inflammatory skin disease that involves dysregulated interplay between immune cells and keratinocytes. Recently, it has been reported that IL-23 induces CCR6+ ?? T cells, which have the pivotal role in psoriasis-like skin inflammation in mice of producing IL-17A and IL-22. Langerhans cells (LCs) are a subset of dendritic cells that reside in the epidermis and regulate immune responses. The role of LCs has been extensively investigated in contact hypersensitivity, but their role in psoriasis remains to be clarified. In this study, we focused on Th17-related factors and assessed the role of LCs and ?? T cells in the development of psoriasis using a mouse psoriasis model triggered by topical application of imiquimod (IMQ). LC depletion by means of diphtheria toxin (DT) in Langerin DT receptor-knocked-in mice suppressed hyperkeratosis, parakeratosis, and ear swelling in the IMQ-treated regions. In addition, LC-depleted mice showed decreased levels of Th17-related cytokines in IMQ-treated skin lesions. Moreover, the IMQ-treated skin of LC-depleted mice showed a decreased number of IL-17A-producing CCR6+ ?? T cells. These results suggest that LCs are required for the development of psoriasis-like lesions induced by IMQ in mice.
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Prostaglandin E2-EP3 Signaling Induces Inflammatory Swelling by Mast Cell Activation.
J. Immunol.
PUBLISHED: 12-16-2013
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PGE2 has long been known as a potentiator of acute inflammation, but its mechanisms of action still remain to be defined. In this study, we employed inflammatory swelling induced in mice by arachidonate and PGE2 as models and dissected the role and mechanisms of action of each EP receptor at the molecular level. Arachidonate- or PGE2-induced vascular permeability was significantly reduced in EP3-deficient mice. Intriguingly, the PGE2-induced response was suppressed by histamine H1 antagonist treatment, histidine decarboxylase deficiency, and mast cell deficiency. The impaired PGE2-induced response in mast cell-deficient mice was rescued upon reconstitution with wild-type mast cells but not with EP3-deficient mast cells. Although the number of mast cells, protease activity, and histamine contents in ear tissues in EP3-deficient mice were comparable to those in wild-type mice, the histamine contents in ear tissues were attenuated upon PGE2 treatment in wild-type but not in EP3-deficient mice. Consistently, PGE2-EP3 signaling elicited histamine release in mouse peritoneal and bone marrow-derived mast cells, and it exerted degranulation and IL-6 production in a manner sensitive to pertussis toxin and a PI3K inhibitor and dependent on extracellular Ca(2+) ions. These results demonstrate that PGE2 triggers mast cell activation via an EP3-Gi/o-Ca(2+) influx/PI3K pathway, and this mechanism underlies PGE2-induced vascular permeability and consequent edema formation.
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Mutations in SERPINB7, encoding a member of the serine protease inhibitor superfamily, cause Nagashima-type palmoplantar keratosis.
Am. J. Hum. Genet.
PUBLISHED: 08-23-2013
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"Nagashima-type" palmoplantar keratosis (NPPK) is an autosomal recessive nonsyndromic diffuse palmoplantar keratosis characterized by well-demarcated diffuse hyperkeratosis with redness, expanding on to the dorsal surfaces of the palms and feet and the Achilles tendon area. Hyperkeratosis in NPPK is mild and nonprogressive, differentiating NPPK clinically from Mal de Meleda. We performed whole-exome and/or Sanger sequencing analyses of 13 unrelated NPPK individuals and identified biallelic putative loss-of-function mutations in SERPINB7, which encodes a cytoplasmic member of the serine protease inhibitor superfamily. We identified a major causative mutation of c.796C>T (p.Arg266(?)) as a founder mutation in Japanese and Chinese populations. SERPINB7 was specifically present in the cytoplasm of the stratum granulosum and the stratum corneum (SC) of the epidermis. All of the identified mutants are predicted to cause premature termination upstream of the reactive site, which inhibits the proteases, suggesting a complete loss of the protease inhibitory activity of SERPINB7 in NPPK skin. On exposure of NPPK lesional skin to water, we observed a whitish spongy change in the SC, suggesting enhanced water permeation into the SC due to overactivation of proteases and a resultant loss of integrity of the SC structure. These findings provide an important framework for developing pathogenesis-based therapies for NPPK.
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Prostaglandin E? is critical for the development of niacin-deficiency-induced photosensitivity via ROS production.
Sci Rep
PUBLISHED: 06-07-2013
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Pellagra is a photosensitivity syndrome characterized by three "Ds": diarrhea, dermatitis, and dementia as a result of niacin deficiency. However, the molecular mechanisms of photosensitivity dermatitis, the hallmark abnormality of this syndrome, remain unclear. We prepared niacin deficient mice in order to develop a murine model of pellagra. Niacin deficiency induced photosensitivity and severe diarrhea with weight loss. In addition, niacin deficient mice exhibited elevated expressions of COX-2 and PGE syntheses (Ptges) mRNA. Consistently, photosensitivity was alleviated by a COX inhibitor, deficiency of Ptges, or blockade of EP4 receptor signaling. Moreover, enhanced PGE2 production in niacin deficiency was mediated via ROS production in keratinocytes. In line with the above murine findings, human skin lesions of pellagra patients confirmed the enhanced expression of Ptges. Niacin deficiency-induced photosensitivity was mediated through EP4 signaling in response to increased PGE2 production via induction of ROS formation.
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Comparison of the efficacy of fexofenadine 120 and 240 mg/day on chronic idiopathic urticaria and histamine-induced skin responses in Japanese populations.
J Dermatolog Treat
PUBLISHED: 05-21-2013
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H1-antihistamines are the first-line treatment of chronic idiopathic urticaria (CIU), but CIU is occasionally refractory to the conventional treatment doses. Guidelines in Europe recommend increasing doses as second-line therapy; however, more supportive evidences for these guidelines are required to justify this management strategy.
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Lymphoid tissue phospholipase A2 group IID resolves contact hypersensitivity by driving antiinflammatory lipid mediators.
J. Exp. Med.
PUBLISHED: 05-20-2013
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Resolution of inflammation is an active process that is mediated in part by antiinflammatory lipid mediators. Although phospholipase A2 (PLA2) enzymes have been implicated in the promotion of inflammation through mobilizing lipid mediators, the molecular entity of PLA2 subtypes acting upstream of antiinflammatory lipid mediators remains unknown. Herein, we show that secreted PLA2 group IID (PLA2G2D) is preferentially expressed in CD11c(+) dendritic cells (DCs) and macrophages and displays a pro-resolving function. In hapten-induced contact dermatitis, resolution, not propagation, of inflammation was compromised in skin and LNs of PLA2G2D-deficient mice (Pla2g2d(-/-)), in which the immune balance was shifted toward a proinflammatory state over an antiinflammatory state. Bone marrow-derived DCs from Pla2g2d(-/-) mice were hyperactivated and elicited skin inflammation after intravenous transfer into mice. Lipidomics analysis revealed that PLA2G2D in the LNs contributed to mobilization of a pool of polyunsaturated fatty acids that could serve as precursors for antiinflammatory/pro-resolving lipid mediators such as resolvin D1 and 15-deoxy-?(12,14)-prostaglandin J2, which reduced Th1 cytokine production and surface MHC class II expression in LN cells or DCs. Altogether, our results highlight PLA2G2D as a "resolving sPLA2" that ameliorates inflammation through mobilizing pro-resolving lipid mediators and points to a potential use of this enzyme for treatment of inflammatory disorders.
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Kallikrein-related peptidase 5 functions in proteolytic processing of profilaggrin in cultured human keratinocytes.
J. Biol. Chem.
PUBLISHED: 04-29-2013
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Filaggrin protein is synthesized in the stratum granulosum of the skin and contributes to the formation of the human skin barrier. Profilaggrin is cleaved by proteolytic enzymes and converted to functional filaggrin, but its processing mechanism remains not fully elucidated. Kallikrein-related peptidase 5 (KLK5) is a major serine protease found in the skin, which is secreted from lamellar granules following its expression in the stratum granulosum and activated in the extracellular space of the stratum corneum. Here, we searched for profilaggrin-processing protease(s) by partial purification of epidermal extracts and found KLK5 as a possible candidate. We used high performance liquid chromatography coupled with electrospray tandem mass spectrometry to show that KLK5 cleaves profilaggrin. Furthermore, based on a proximity ligation assay, immunohistochemistry, and immunoelectron microscopy analysis, we reveal that KLK5 and profilaggrin co-localize in the stratum granulosum in human epidermis. KLK5 knockdown in normal cultured human epidermal keratinocytes resulted in higher levels of profilaggrin, indicating that KLK5 potentially functions in profilaggrin cleavage.
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Intravital analysis of vascular permeability in mice using two-photon microscopy.
Sci Rep
PUBLISHED: 04-05-2013
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Blood vessel endothelium forms a semi-permeable barrier and its permeability controls the traffics of plasma contents. Here we report an intravital evaluation system for vascular permeability in mice using two-photon microscopy. We used various sizes of fluorescein-conjugated dextran as a tracer and its efflux was quantified by measuring the changes of fluorescent intensity both on the blood vessel area and the interstitial space. Using this system, we demonstrated that skin blood vessels limited the passage of dextran larger than 70 kDa under homeostatic conditions. We evaluated the kinetics of vascular permeability in histamine- or IgE-induced type I allergic models and a hapten-induced type IV allergic model. In such inflammatory conditions, the hyperpermeability was selectively induced in the postcapillary venules and dextran as large as 2000-kDa leaked from the bloods. Taken together, our study provides a convenient method to characterize the skin blood vessels as a traffic barrier in physiological conditions.
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A double dose of levocetirizine leads to better control of histamine-induced flare, wheal and itch in healthy donors.
Pharmacology
PUBLISHED: 03-21-2013
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Levocetirizine is classified as a nonsedating second-generation antihistamine. This drug is used to treat allergic disorders such as urticaria and pruritus. Thus far, studies have demonstrated an increase in efficacy for refractory urticaria by increasing doses of antihistamines; however, more lines of supportive evidence for these guidelines are required to justify this management strategy. In this study, we found that a double dose of levocetirizine suppressed histamine-induced flare formation more rapidly and sustainably, and wheal and itch more extensively, compared with the conventional dose using both visual and laser Doppler imaging scales in a noninvasive manner. These results suggest that double-dosed levocetirizine treatment suppresses histamine-induced skin symptoms more rapidly, profoundly and sustainably than conventionally dosed levocetirizine treatment.
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Serum granulysin as a possible key marker of the activity of alopecia areata.
J. Dermatol. Sci.
PUBLISHED: 03-17-2013
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Alopecia areata (AA) is an organ-restricted autoimmune condition of the hair follicles (HFs) that presents as nonscarring hair loss. A collapse of immunoprivilege for cell-mediated cytotoxicity and following attacks by cytotoxic T cells to anagen HFs are considered to play a major role in the pathogenesis of AA. However, there has been no useful marker for the activity of AA to date.
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D1-like dopamine receptors antagonist inhibits cutaneous immune reactions mediated by Th2 and mast cells.
J. Dermatol. Sci.
PUBLISHED: 03-13-2013
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Dopamine transduces signals via five subtypes of G protein-coupled receptors. Among these subtypes, the D1 and D5 receptors belong to the D1-like group. Although dopamine is known to mediate immune responses, its involvement in cutaneous immunity remains unclear.
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Basophils are required for the induction of Th2 immunity to haptens and peptide antigens.
Nat Commun
PUBLISHED: 03-13-2013
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The relative contributions of basophils and dendritic cells in Th2 skewing to foreign antigen exposure remain unclear. Here we report the ability of basophils to induce Th2 polarization upon epicutaneous sensitization with different antigens using basophil conditionally depleted Bas TRECK transgenic mice. Basophils are responsible for Th2 skewing to haptens and peptide antigens, but not protein antigens in vivo. Consistent with this, basophils cannot take up or process ovalbumin protein in significant quantities, but present ovalbumin peptide to T cells for Th2 differentiation via major histocompatibility complex class II. Intriguingly, basophils promote Th2 skewing upon ovalbumin protein exposure in the presence of dendritic cells. Taken together, our results suggest that basophils alone are able to induce Th2 skewing with haptens and peptide antigens but require dendritic cells for the induction of Th2 for protein antigens upon epicutaneous immunization.
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Mast cell maturation is driven via a group III phospholipase A2-prostaglandin D2-DP1 receptor paracrine axis.
Nat. Immunol.
PUBLISHED: 03-11-2013
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Microenvironment-based alterations in phenotypes of mast cells influence the susceptibility to anaphylaxis, yet the mechanisms underlying proper maturation of mast cells toward an anaphylaxis-sensitive phenotype are incompletely understood. Here we report that PLA2G3, a mammalian homolog of anaphylactic bee venom phospholipase A2, regulates this process. PLA2G3 secreted from mast cells is coupled with fibroblastic lipocalin-type PGD2 synthase (L-PGDS) to provide PGD2, which facilitates mast-cell maturation via PGD2 receptor DP1. Mice lacking PLA2G3, L-PGDS or DP1, mast cell-deficient mice reconstituted with PLA2G3-null or DP1-null mast cells, or mast cells cultured with L-PGDS-ablated fibroblasts exhibited impaired maturation and anaphylaxis of mast cells. Thus, we describe a lipid-driven PLA2G3-L-PGDS-DP1 loop that drives mast cell maturation.
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Evaluation of basophil infiltration into the skin lesions of tick bites.
Case Rep Dermatol
PUBLISHED: 02-22-2013
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Recently, it has been described that basophils play an essential role in antibody-mediated acquired immunity against ticks in mice. However, it is still unknown whether basophil infiltration has any significance in the infestation with ticks in humans. In this report, we have evaluated the infiltration of basophils into human skin lesions of tick bites.
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Possible new therapeutic strategy to regulate atopic dermatitis through upregulating filaggrin expression.
J. Allergy Clin. Immunol.
PUBLISHED: 02-21-2013
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Nonsense mutations in filaggrin (FLG) represent a significant genetic factor in the cause of atopic dermatitis (AD).
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Subcorneal Pustular Dermatosis Exhibiting a High Serum TARC/CCL17 Level.
Case Rep Dermatol
PUBLISHED: 02-21-2013
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Subcorneal pustular dermatosis (SPD) is a rare, relapsing, symmetric sterile pustular eruption that dominantly involves flexural areas. It is considered one form of neutrophilic dermatoses, which are associated with interleukin (IL)-17-producing T helper (Th) 17 cells that induce IL-8 production. We have previously reported that Th17 might be involved in the pathomechanism of Th2-dominant atopic dermatitis [Koga et al.: J Invest Dermatol 2008;128:2625-2630]. On the other hand, it has been a debate whether Th2 is involved in the etiology of neutrophilic dermatoses. Herein, we report a case of SPD that exhibited a high serum thymus and activation-regulated chemokine/chemokine (C-C motif) ligand 17 level, thereby raising the possibility of a Th2 association in its pathogenesis. Although it was limited to a single observation, our case raised the possibility that SPD may possess Th2 properties.
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Sweets syndrome associated with systemic lupus erythematosus: a case report and review of the literature.
J. Dermatol.
PUBLISHED: 01-21-2013
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A 35-year-old Japanese female patient with systemic lupus erythematosus (SLE) presented with fever, erythematous papules and nodules, and polyarthralgia. Skin biopsy of a nodule was compatible with Sweets syndrome. The papules/nodules were well treated with an oral glucocorticoid. Thirty cases of Sweets syndrome associated with lupus erythematosus (LE) have been reported in the published work. The mean age was 34.2 years. They showed a higher male ratio (male : female, 1:2) compared with patients with SLE (1:9) and Sweets syndrome (1:3.7). Sweets syndrome may occur as a manifestation of LE, and a moderate dose of an oral glucocorticoid will result in a good response.
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Analysis of cell movement between skin and other anatomical sites in vivo using photoconvertible fluorescent protein "Kaede"-transgenic mice.
Methods Mol. Biol.
PUBLISHED: 01-18-2013
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Clarification of the spatiotemporal regulation and function of immune cells within the skin is critical to the understanding of the role of immune cells and the skin in immune homeostasis. Here, we describe a novel assay system for monitoring cell movements in the entire body using the photoconvertible fluorescent protein "Kaede"-transgenic (Tg) mice. We can label immune cells by the change in color of Kaede from green to red in these cells following exposure to violet light and track these cells in the entire body. The Kaede-Tg system is an ideal tool for monitoring precise cellular movements between the skin and other anatomical sites in vivo at different stages of the immune response.
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Protease activity enhances production of thymic stromal lymphopoietin and basophil accumulation in flaky tail mice.
Am. J. Pathol.
PUBLISHED: 01-17-2013
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Epidermal barrier abnormality due to filaggrin deficiency is an important predisposing factor in the development of atopic dermatitis (AD). In addition, the expression of thymic stromal lymphopoietin (TSLP) in keratinocytes (KCs), induced by barrier disruption, can promote type 2 helper T-cell polarization. Protease activity, including protease-activated receptor-2 (PAR-2), is also known to be involved in epidermal barrier function in AD. However, to our knowledge, the relationship between protease activity and filaggrin deficiency from the perspective of AD has not been elucidated. Flaky tail (Flg(ft)) mice, known to have a mutation in the filaggrin gene, were used to assess the role of protease in KCs in the steady state and the mite-induced AD-like skin inflammation model. In the steady state, the expression and activity levels of endogenous proteases, kallikreins 5, 7, and 14, in the skin and TSLP were higher in Flg(ft) than in control mice. In addition, activation of PAR-2 by its agonist induced the production of TSLP in KCs of Flg(ft) mice, which was abrogated by a newly developed PAR-2 antagonist. Application of the PAR-2 antagonist improved symptoms and basophil accumulation in Flg(ft) mice treated with mite extracts. These results suggest that possibly through the PAR-2 activation in KCs, filaggrin deficiency induces TSLP production and basophil accumulation, which play important roles in the establishment of AD.
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TGF?1, an epidermal controller of skin dendritic cell homeostasis.
J. Invest. Dermatol.
PUBLISHED: 01-10-2013
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Transforming growth factor-?1 (TGF?1) is generally regarded as an anti-inflammatory cytokine. However, previous studies suggest that TGF?1 can promote immune responses under certain conditions. In this issue, Mohammed et al. report that epidermal keratinocyte-derived TGF?1 alone can alter homeostasis of multiple cutaneous dendritic cell (DC) subsets, which may enhance skin inflammation. These findings may provide a better understanding of the pathogenesis of inflammatory skin disorders such as psoriasis, although how keratinocyte-derived TGF?1 regulates cutaneous DCs under physiological and inflammatory conditions should be further addressed.
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New concept of the pathogenesis of atopic dermatitis: interplay among the barrier, allergy, and pruritus as a trinity.
J. Dermatol. Sci.
PUBLISHED: 01-03-2013
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Atopic dermatitis (AD) is a common skin condition, characterized by a complex, heterogeneous pathogenesis, including skin barrier dysfunctions, allergy/immunology, and pruritus. When the skin barrier is disrupted by, for example, the filaggrin gene mutation and/or environmental factors, the skin is predisposed to being penetrated by external stimuli. Foreign antigens can be subdivided into two subsets by size: haptens (including metals) and protein antigens. It is known that a single hapten challenge provokes Th1 initially, but that repeated elicitation with haptens results in a shift toward Th2-dominated responses. On the other hand, exposure to protein antigens directly induces Th2-dominant conditions via the thymic stromal lymphopoietin (TSLP) receptor on Langerhans cells. Recently, it has been revealed that Th2 cells produce IL-31, which provokes pruritus, and that Th2 cytokines decrease filaggrin expressions by keratinocytes. These findings suggest that Th2 conditions lead to pruritus and barrier dysfunctions. In this review, we will examine the highly complex interplay among skin barrier abnormality, allergy/immunology, and pruritus as a trinity in the development of AD.
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Prostaglandin E2-EP3 axis in fine-tuning excessive skin inflammation by restricting dendritic cell functions.
PLoS ONE
PUBLISHED: 01-01-2013
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Prostaglandin E2 (PGE2) is produced in the skin and is suggested to play a role in the regulation of cutaneous immune homeostasis and responses. However, the multifaceted functions of PGE2 continue to elude our understanding, especially because of the multiplicity of PGE2 receptors--EP1, EP2, EP3, and EP4. While cAMP-elevating EP4 is known to activate the functions of cutaneous dendritic cells (DCs), including Langerhans cells (LCs) and dermal DCs, the role of cAMP-suppressing EP3 in this process remains unknown. Here we demonstrated that an EP3 receptor selective agonist, ONO-AE-248, inhibited chemotaxis and co-stimulatory molecule expressions of DCs in vitro. A suboptimal dose of antigen was sufficient to induce contact hypersensitivity in EP3-deficient mice. Intriguingly, EP3 deficiency did not impair skin inflammation at all when the antigen dose was sufficiently high. EP3 limited the functions of cutaneous DCs only when the antigen dose was low. In contrast to EP4, the observed unappreciated function of EP3 may stabilize the cutaneous DCs to halt the impetuous response to a suboptimal dose of antigen. Taken together, PGE2-EP3 signaling is essential for fine-tuning excessive skin inflammation by restricting DC functions.
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A Case of Foreign-Body Granuloma of the Glabella due to Polyacrylamide Filler and an Intractable Ulcer after Skin Biopsy: An Immunohistochemical Evaluation of Inflammatory Changes.
Case Rep Dermatol
PUBLISHED: 01-01-2013
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Polyacrylamide hydrogel has been considered a safe and biocompatible soft tissue filler, and it has been widely used in cosmetic procedures. However, recent studies have revealed some complications with polyacrylamide filler injections.
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Evaluation of the Effectiveness of Antibiotics against Eosinophilic Pustular Folliculitis.
Case Rep Dermatol
PUBLISHED: 01-01-2013
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Eosinophilic pustular folliculitis (EPF) is a chronic intractable pruritic dermatosis. Although indomethacin is generally effective against EPF and considered as a first-line therapy, quite a few patients with indomethacin still suffer from the symptoms. Among other therapeutic options, some antibiotics have been reported to be effective; however, there has been no epidemiological description regarding oral antibiotics use in patients with EPF. In this study, we investigated the frequency of antibiotics use and the effectiveness in patients with EPF.
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Reduction of Skin pH during Treatment for Palmoplantar Hyperhidrosis: A Conjecture on the Role of pH-Regulated Water Channel, i.e. Aquaporin.
Case Rep Dermatol
PUBLISHED: 01-01-2013
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Primary palmoplantar hyperhidrosis (PPH) is a disorder that involves excessive sweating on the palms and soles. Although the pathophysiology of PPH remains unknown, some treatments, including topical aluminum chloride (AC) and tap water iontophoresis (TWI), are effective at suppressing the perspiration. Herein, we report the kinetics of the skin pH of two cases of PPH treated with AC and TWI. We found that the skin pH decreased in accordance with the reduction in sweating. This finding indicates that the reduction in sweating may be attributed to the reduction of skin pH in AC and TWI. Whether or not the pH-regulated function of aquaporin can explain this finding remains unknown.
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Normal immunostaining pattern for aquaporin-5 in the lesions of palmoplantar hyperhidrosis.
Case Rep Dermatol
PUBLISHED: 01-01-2013
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Aquaporin-5 (AQP-5) is a water-transporting protein expressed in mammal sweat glands. It has been reported that the expression of AQP-5 is involved in sweating of mice, rats, and horses. However, the physiological function of human AQP-5 is still uncertain. In this report, we examined the expression pattern of AQP-5 in the skin lesions of palmoplantar hyperhidrosis in patients with Nagashima-type palmoplantar hyperkeratosis (PPK). We found that there was no significant difference in AQP-5 expression in the palmoplantar skin of healthy subjects and patients with palmoplantar hyperhidrosis. Our findings suggest that a mechanism other than AQP-5 may be involved in the pathogenesis of hyperhidrosis in PPK.
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Possible nagashima-type palmoplantar keratosis in two siblings.
Case Rep Dermatol
PUBLISHED: 01-01-2013
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Nagashima-type palmoplantar keratosis (PPK) is an autosomal recessive, transgressive and non-progressive form of PPK. It was once described as a mild form of mal de Meleda, but it is now proposed as a novel entity of PPK. Since its pathogenesis remains unclear, it is important to clarify the mode of inheritance. Here, we present a case of possible Nagashima-type PPK in 2 siblings. The siblings had non-affected parents, suggesting that the mode of inheritance was autosomal recessive. At present, reports on PPK in the English literature are limited, and thus the clinical features of Nagashima-type PPK may not be well appreciated in Western countries. More reports and concise clinical observations with genetic studies are required to establish this new entity of PPK.
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Involvement of aquaporin-7 in the cutaneous primary immune response through modulation of antigen uptake and migration in dendritic cells.
FASEB J.
PUBLISHED: 10-03-2011
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Dendritic cells (DCs) have the ability to present antigen and play a critical role in the induction of the acquired immune response. Skin DCs uptake antigen and subsequently migrate to regional draining lymph nodes (LNs), where they activate naive T cells. Here we show that the water/glycerol channel protein aquaporin 7 (AQP7) is expressed on epidermal and dermal DCs and involved in the initiation of primary immune responses. AQP7-deficient DCs showed a decreased cellular uptake of low-molecular-mass compounds (fluorescein isothiocyanate and Lucifer yellow) and high-molecular-mass substances (ovalbumin and dextran), suggesting that AQP7 is involved in antigen uptake. AQP7-deficient DCs also exhibited reduced chemokine-dependent cell migration in comparison to wild-type DCs. Consistent with these in vitro results, AQP7-deficient mice demonstrated a reduced accumulation of antigen-retaining DCs in the LNs after antigen application to the skin, which could be attributed to decreased antigen uptake and migration. Coincidentally, AQP7-deficient mice had impaired antigen-induced sensitization in a contact hypersensitivity model. These observations suggested that AQP7 in skin DCs is primarily involved in antigen uptake and in the subsequent migration of DCs and is responsible for antigen presentation and the promotion of downstream immune responses.
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Filaggrin in atopic dermatitis: flaky tail mice as a novel model for developing drug targets in atopic dermatitis.
Inflamm Allergy Drug Targets
PUBLISHED: 09-01-2011
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The barrier abnormality, a loss-of-function mutation in the gene encoding filaggrin (FLG), which is linked to the incidence of atopic dermatitis (AD), is a recently discovered but important factor in the pathogenesis of AD. To investigate this issue in greater detail, mice that have a genetic defect (FLG) in barrier function will provide a model of AD closer to the human disease. Flaky tail (Flg(ft)) mice, essentially deficient in filaggrin, recently have been introduced to investigate the role of filaggrin on AD. These mice showed eczematous skin lesion in the steady state in line with increased of total IgE and Th17 expression in the skin. There is also an altered skin barrier function as a key element of AD either outside-to-inside barrier function or vice versa in Flg(ft) mice. Moreover, like human AD, these mice showed enhanced percutaneous allergen priming or response to cutaneous stimulants. Application of mite allergen in Flg(ft) mice, even without prior barrier disruption, remarkably enhanced both the clinical manifestations and the laboratory findings that correspond to indicators of human AD. These features of Flg(ft) mice allow us to investigate further the role of filaggrin in AD, and the knowledge obtained using these mice will be quite useful to develop a new therapeutic target for AD.
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PGD2 induces eotaxin-3 via PPAR? from sebocytes: a possible pathogenesis of eosinophilic pustular folliculitis.
J. Allergy Clin. Immunol.
PUBLISHED: 08-05-2011
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Eosinophilic pustular folliculitis (EPF) is a chronic intractable pruritic dermatosis characterized by massive eosinophil infiltrates involving the pilosebaceous units. Recently, EPF has been regarded as an important clinical marker of HIV infection, and its prevalence is increasing in number. The precise mechanism by which eosinophils infiltrate into the pilosebaceous units remains largely unknown. Given that indomethacin, a COX inhibitor, can be successfully used to treat patients with EPF, we can assume that COX metabolites such as prostaglandins (PGs) are involved in the etiology of EPF.
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Skin as a peripheral lymphoid organ: revisiting the concept of skin-associated lymphoid tissues.
J. Invest. Dermatol.
PUBLISHED: 07-07-2011
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Antigen presentation to T cells is essential for the induction of adaptive immunity. This event takes place not solely in the lymph node (LN) but also in the skin. Recent in vivo trafficking studies using Kaede-transgenic mice reveal that skin-homing effector memory T cells alter their effector function and homing ability by transitioning to a central memory T cell-like phenotype through antigen recognition that occurs in the skin. In addition, these cells travel back and forth between the skin and draining LNs. These studies are evocative of the classic concept of skin-associated lymphoid tissues and underscore the critical role of skin as a peripheral lymphoid organ.
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A GPR40 agonist GW9508 suppresses CCL5, CCL17, and CXCL10 induction in keratinocytes and attenuates cutaneous immune inflammation.
J. Invest. Dermatol.
PUBLISHED: 05-19-2011
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G-protein coupled receptors (GPCR) exert diverse physiological functions, many of which are exploited therapeutically. The roles of GPCR in keratinocytes in immune response in the skin, however, remain poorly defined. In this study, we focused on Gi-coupled GPCR in keratinocytes and defined their actions in immunoactivation of cultured keratinocytes in vitro and immune reaction in the skin in vivo. We first activated HaCaT cells by tumor necrosis factor (TNF)-? and IFN-? and examined effects of various ligands for GPCR on production of CCL17 and CCL5. Agonists for Gi-coupled receptors, particularly GW9508 for GPR40, inhibited CCL17 and CCL5 expression in a pertussis toxin-sensitive manner. The inhibitory effect by GW9508 was abrogated by depletion of GPR40 with RNA interference. GW9508 further suppressed expression of IL-11, IL-24, and IL-33 induced in HaCaT cells by TNF-? and IFN-?. GW9508 also inhibited CCL5 and CXCL10 production by normal human epidermal keratinocytes. Administration of GW9508 topically to the skin in the challenging phase suppressed ear swelling in a repeated hapten application model and contact hypersensitivity with downregulation of CCL5 and CXCL10, respectively. Thus, in the skin, stimulation of Gi-coupled receptors attenuates induction of critical cytokines and chemokines by proinflammatory cytokines in keratinocytes and suppresses allergic inflammation in the skin.
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Requirement of interaction between mast cells and skin dendritic cells to establish contact hypersensitivity.
PLoS ONE
PUBLISHED: 05-12-2011
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The role of mast cells (MCs) in contact hypersensitivity (CHS) remains controversial. This is due in part to the use of the MC-deficient Kit (W/Wv) mouse model, since Kit (W/Wv) mice congenitally lack other types of cells as a result of a point mutation in c-kit. A recent study indicated that the intronic enhancer (IE) for Il4 gene transcription is essential for MCs but not in other cell types. The aim of this study is to re-evaluate the roles of MCs in CHS using mice in which MCs can be conditionally and specifically depleted. Transgenic Mas-TRECK mice in which MCs are depleted conditionally were newly generated using cell-type specific gene regulation by IE. Using this mouse, CHS and FITC-induced cutaneous DC migration were analyzed. Chemotaxis assay and cytoplasmic Ca²? imaging were performed by co-culture of bone marrow-derived MCs (BMMCs) and bone marrow-derived dendritic cells (BMDCs). In Mas-TRECK mice, CHS was attenuated when MCs were depleted during the sensitization phase. In addition, both maturation and migration of skin DCs were abrogated by MC depletion. Consistently, BMMCs enhanced maturation and chemotaxis of BMDC in ICAM-1 and TNF-? dependent manners Furthermore, stimulated BMDCs increased intracellular Ca²? of MC upon direct interaction and up-regulated membrane-bound TNF-? on BMMCs. These results suggest that MCs enhance DC functions by interacting with DCs in the skin to establish the sensitization phase of CHS.
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Prostaglandin E2-prostaglandin E receptor subtype 4 (EP4) signaling mediates UV irradiation-induced systemic immunosuppression.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 04-01-2011
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UV radiation induces systemic immunosuppression. Because nonsteroidal anti-inflammatory drugs suppress UV-induced immunosuppression, prostanoids have been suspected as a crucial mediator of this UV effect. However, the identity of the prostanoid involved and its mechanism of action remain unclear. Here, we addressed this issue by subjecting mice deficient in each prostanoid receptor individually or mice treated with a subtype-specific antagonist to UV irradiation. Mice treated with an antagonist for prostaglandin E receptor subtype 4 (EP4), but not those deficient in other prostanoid receptors, show impaired UV-induced immunosuppression, whereas administration of an EP4 agonist rescues the impairment of the UV-induced immunosuppression in indomethacin-treated mice. The EP4 antagonist treatment suppresses an increase in the number of CD4(+)/forkhead box P3-positive (Foxp3(+)) regulatory T cells (Treg cells) in the peripheral lymph nodes (LNs) and dendritic cells expressing DEC205 in the LNs and the skin after UV irradiation. Furthermore, the EP4 antagonist treatment down-regulates UV-induced expression of receptor activator of NF-?B ligand (RANKL) in skin keratinocytes. Finally, administration of anti-RANKL antibody abolishes the restoration of UV-induced immunosuppression by EP4 agonism in indomethacin-treated mice. Thus, prostaglandin E(2) (PGE(2))-EP4 signaling mediates UV-induced immunosuppression by elevating the number of Treg cells through regulation of RANKL expression in the epidermis.
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Regulatory T cells in cutaneous immune responses.
J. Dermatol. Sci.
PUBLISHED: 02-11-2011
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Regulatory T cells (Treg) are a subset of T cells with strong immunosuppressive activity. In the skin, it has recently been revealed that Treg play important roles not only in the maintenance of skin homeostasis but also in the regulation of the immune responses, such as contact hypersensitivity and atopic dermatitis. Furthermore, the skin plays important roles in the induction of Treg in the periphery. In this review, we will provide an overview of the mechanism of Treg-mediated immunosuppression and discuss the role of Treg in the skin.
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Topical cholecystokinin depresses itch-associated scratching behavior in mice.
J. Invest. Dermatol.
PUBLISHED: 02-03-2011
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Cholecystokinin (CCK) serves as a gastrointestinal hormone and also functions as a neuropeptide in the central nervous system (CNS). CCK may be a downregulator in the CNS, as represented by its anti-opioid properties. The existence of CCK in the peripheral nervous system has also been reported. We investigated the suppressive effects of various CCKs on peripheral pruritus in mice. The clipped backs of ICR mice were painted with CCK synthetic peptides and injected intradermally with substance P (SP). The frequency of SP-induced scratching was reduced significantly by topical application of sulfated CCK8 (CCK8S) and CCK7 (CCK7S), but not by nonsulfated CCK8, CCK7, or CCK6. Dermal injection of CCK8S also suppressed the scratching frequency, suggesting that dermal cells as well as epidermal keratinocytes (KCs) are the targets of CCKs. As determined using real-time PCR, mRNA for CCK2R, one of the two types of CCK receptors, was expressed highly in mouse fetal skin-derived mast cells (FSMCs) and moderately in ICR mouse KCs. CCK8S decreased in vitro compound 48/80-promoted degranulation of FSMCs with a transient elevation of the intracellular calcium concentration. These findings suggest that CCK may exert an antipruritic effect via mast cells and that topical CCK may be clinically useful for pruritic skin disorders.
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Specific substance of Maruyama (SSM) suppresses immune responses in atopic dermatitis-like skin lesions in DS-Nh mice by modulating dendritic cell functions.
J. Dermatol. Sci.
PUBLISHED: 01-25-2011
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Specific substance of Maruyama (SSM) is a carcinostatic immunotherapeutic agent extracted from Mycobacterium tuberculosis. The efficacy of SSM induced interleukin(IL)-12 and IFN-? production, and inhibition of IL-4, resulting in a shift from Th2 to Th1 in vivo.
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Generalized vitiligo and associated autoimmune diseases in Japanese patients and their families.
Allergol Int
PUBLISHED: 01-13-2011
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Generalized vitiligo is an acquired disorder in which depigmented macules result from the autoimmune loss of melanocytes from the involved regions of skin. Generalized vitiligo is frequently associated with other autoimmune diseases, particularly autoimmune thyroid diseases (Hashimotos thyroiditis and Graves disease), rheumatoid arthritis, adult-onset type 1 diabetes mellitus, psoriasis, pernicious anemia, systemic lupus erythematosus, and Addisons disease.
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Upregulation of aquaporin-3 is involved in keratinocyte proliferation and epidermal hyperplasia.
J. Invest. Dermatol.
PUBLISHED: 12-30-2010
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Aquaporin-3 (AQP3) is a water/glycerol-transporting protein expressed in keratinocytes of the epidermis. We previously showed that AQP3-mediated transport of water and glycerol is involved in keratinocyte migration and proliferation, respectively. However, the involvement of AQP3 in epidermal hyperplasia in skin diseases, such as atopic dermatitis (AD), is unknown. In this study, we found significantly increased AQP3 transcript and protein expression in the epidermis of human AD lesions. The upregulation of AQP3 expression in human keratinocytes by transfection with human AQP3 DNA plasmid was associated with increased cellular glycerol and ATP, as well as increased cell proliferation. Among several cytokines and chemokines produced in the skin, CCL17, which is highly expressed in AD, was found to be a strong inducer of AQP3 expression and enhanced keratinocyte proliferation. In mouse AD models, AQP3 was strongly overexpressed in the epidermis in wild-type mice. Epidermal hyperplasia was reduced in AQP3-deficient mice, with a decreased number of proliferating keratinocytes. These results suggest the involvement of AQP3 in epidermal hyperplasia by a mechanism involving upregulated AQP3 expression and consequent enhancement of keratinocyte proliferation.
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Rho-mDia1 pathway is required for adhesion, migration, and T-cell stimulation in dendritic cells.
Blood
PUBLISHED: 09-29-2010
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Dendritic cells (DCs) are essential for the initiation of acquired immune responses through antigen acquisition, migration, maturation, and T-cell stimulation. One of the critical mechanisms in this response is the process actin nucleation and polymerization, which is mediated by several groups of proteins, including mammalian Diaphanous-related formins (mDia). However, the role of mDia in DCs remains unknown. Herein, we examined the role of mDia1 (one of the isoforms of mDia) in DCs. Although the proliferation and maturation of bone marrow-derived DCs were comparable between control C57BL/6 and mDia1-deficient (mDia1(-/-)) mice, adhesion and spreading to cellular matrix were impaired in mDia1(-/-) bone marrow-derived DCs. In addition, fluorescein isothiocyanate-induced cutaneous DC migration to draining lymph nodes in vivo and invasive migration and directional migration to CCL21 in vitro were suppressed in mDia1(-/-) DCs. Moreover, sustained T-cell interaction and T-cell stimulation in lymph nodes were impaired by mDia1 deficiency. Consistent with this, the DC-dependent delayed hypersensitivity response was attenuated by mDia1-deficient DCs. These results suggest that actin polymerization, which is mediated by mDia1, is essential for several aspects of DC-initiated acquired immune responses.
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FTY720 regulates bone marrow egress of eosinophils and modulates late-phase skin reaction in mice.
Am. J. Pathol.
PUBLISHED: 08-27-2010
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Eosinophilia in the blood and skin is frequently observed in patients with certain inflammatory skin diseases, such as atopic dermatitis. However, the mechanism underlying eosinophil circulation and the role of eosinophils in cutaneous immune responses remain unclear. In repeated hapten application-induced cutaneous responses in BALB/c mice, the administration of FTY720 before the last challenge decreased the number of skin-infiltrating eosinophils and reduced the late-phase reaction. A similar reduction of the late-phase reaction was observed by a sphingosine-1-phosphate G protein-coupled receptor (S1P1)-selective agonist, SEW2871. We monitored numerous alterations of eosinophils in the blood, spleen, bone marrow, and lymph nodes of interleukin-5 transgenic mice, used as an eosinophilia model, following FTY720 administration. The number of circulating eosinophils was significantly decreased after treatment with FTY720, and eosinophils accumulated in the bone marrow. In addition, eosinophils expressed S1P1, S1P3, and S1P4 mRNAs, and their chemotactic response to S1P was abolished by FTY720 as well as by SEW2871. These findings suggest that FTY720 affects the number of eosinophils in both the blood and skin by inhibiting the egress of eosinophils from the bone marrow and thus downmodulating the late-phase reaction.
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Prostanoid receptors as possible targets for anti-allergic drugs: recent advances in prostanoids on allergy and immunology.
Curr Drug Targets
PUBLISHED: 08-04-2010
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Prostanoids, consisting of prostaglandins and thromboxane, are cyclooxygenase metabolites of arachidonic acid released in various pathophysiological conditions which exert a range of actions mediated through their respective receptors expressed on target cells. Although it has been difficult to analyze the physiological role of prostanoids, recent developments in both the disruption of the respective gene and receptor selective compounds have enabled us to investigate the physiological roles for each receptor. It has been demonstrated that each prostanoid receptor has multiple functions, and that their expression is regulated in a context-dependent manner that sometimes results in opposite, excitatory and inhibitory, outcomes. The balance of prostanoid production and receptor expression has been revealed to be important for homeostasis of the human body. Here, we review new findings on the roles of prostanoids in allergic and immune diseases, focusing on contact dermatitis, atopic dermatitis, asthma, rheumatoid arthritis, and encephalomyelitis, and also discuss the clinical potentials of receptor-selective drugs.
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Modulation of semaphorin 3A expression by calcium concentration and histamine in human keratinocytes and fibroblasts.
J. Dermatol. Sci.
PUBLISHED: 04-30-2010
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Both neurotrophins and chemorepellents are involved in the elongation and sprouting of itch-associated C-fibers in the skin. Nerve growth factor (NGF) and semaphorin 3A (Sema3A) are representatives of these two types of axon-guidance factors, respectively.
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The mandatory role of IL-10-producing and OX40 ligand-expressing mature Langerhans cells in local UVB-induced immunosuppression.
J. Immunol.
PUBLISHED: 04-16-2010
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The mechanism underlying the local UVB-induced immunosuppression is a central issue to be clarified in photoimmunology. There have been reported a considerable number of cells and factors that participate in the sensitization phase-dependent suppression, including Langerhans cells (LCs), regulatory T cells, IL-10, and TNF-alpha. The recent important finding that LC-depleted mice rather exhibit enhanced contact hypersensitivity responses urged us to re-evaluate the role of LCs along with dermal dendritic cells (dDCs) in the mechanism of UVB-induced immunosuppression. We studied the surface expression of OX40 ligand (OX40L) and the intracellular expression of IL-10 in LCs and dDCs from UVB-irradiated (300 mJ/cm(2)) skin of BALB/c mice and those migrating to the regional lymph nodes from UVB-irradiated, hapten-painted mice. In epidermal and dermal cell suspensions prepared from the UVB-irradiated skin, LCs expressed OX40L as well as CD86 and produced IL-10 at a higher level than Langerin(-) dDCs. The UVB-induced immunosuppression was attenuated by the administration of IL-10-neutralizing or OX40L-blocking Abs. In mice whose UVB-irradiated, hapten-painted skin was dissected 1 d after hapten application, the contact hypersensitivity response was restored, because this treatment allowed dDCs but not LCs to migrate to the draining lymph nodes. Moreover, LC-depleted mice by using Langerin-diphtheria toxin receptor-knocked-in mice showed impaired UVB-induced immunosuppression. These results suggest that IL-10-producing and OX40L-expressing LCs in the UVB-exposed skin are mandatory for the induction of Ag-specific regulatory T cells.
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Prostaglandin I2-IP signaling promotes Th1 differentiation in a mouse model of contact hypersensitivity.
J. Immunol.
PUBLISHED: 04-16-2010
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PGI(2), which exerts its actions via its specific Gs-coupled I prostanoid receptor (IP), is known to be present in the lymph nodes, but its roles in acquired cutaneous immune responses remain unclear. To investigate the role of PGI(2)-IP signaling in cutaneous immune responses, we applied IP-deficient (Ptgir(-/-)) mice to contact hypersensitivity as a model of acquired immune response and found that Ptgir(-/-) mice exhibited a significantly decreased contact hypersensitivity response. Lymph node cells from sensitized Ptgir(-/-) mice exhibited decreased IFN-gamma production and a smaller T-bet(+) subset compared with control mice. PGI synthase and IP expression were detected in dendritic cells and T cells, respectively, by quantitative real-time PCR analysis, suggesting that PGI(2) produced by dendritic cells acts on IP in T cells. In fact, in vitro Th1 differentiation was enhanced by an IP agonist, and this enhancement was nullified by protein kinase A inhibitor. These results suggest that PGI(2)-IP signaling promotes Th1 differentiation through a cAMP-protein kinase A pathway and thereby initiates acquired cutaneous immune responses.
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Flaky tail mouse denotes human atopic dermatitis in the steady state and by topical application with Dermatophagoides pteronyssinus extract.
Am. J. Pathol.
PUBLISHED: 03-19-2010
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The barrier abnormality, a loss-of-function mutation in the gene encoding filaggrin (FLG), which is linked to the incidence of atopic dermatitis (AD), is a recently discovered but important factor in the pathogenesis of AD. Flaky tail (Flg(ft)) mice, essentially deficient in filaggrin, have been used to investigate the role of filaggrin on AD. However, the relevancy of Flg(ft) mice to human AD needs to be determined further. In this study, we observed the clinical manifestations of Flg(ft) mice in the steady state and their cutaneous immune responses against external stimuli, favoring human AD. Under specific pathogen-free conditions, the majority of Flg(ft) mice developed clinical and histological eczematous skin lesions similar to human AD with outside-to-inside skin barrier dysfunction evaluated by newly devised methods. In addition, cutaneous hapten-induced contact hypersensitivity as a model of acquired immune response and a mite extract-induced dermatitis model physiologically relevant to a human AD were enhanced in Flg(ft) mice. These results suggest that the Flg(ft) mouse genotype has potential as an animal model of AD corresponding with filaggrin mutation in human AD.
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Activated regulatory T cells are the major T cell type emigrating from the skin during a cutaneous immune response in mice.
J. Clin. Invest.
PUBLISHED: 02-22-2010
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Tregs play an important role in protecting the skin from autoimmune attack. However, the extent of Treg trafficking between the skin and draining lymph nodes (DLNs) is unknown. We set out to investigate this using mice engineered to express the photoconvertible fluorescence protein Kaede, which changes from green to red when exposed to violet light. By exposing the skin of Kaede-transgenic mice to violet light, we were able to label T cells in the periphery under physiological conditions with Kaede-red and demonstrated that both memory phenotype CD4+Foxp3- non-Tregs and CD4+Foxp3+ Tregs migrated from the skin to DLNs in the steady state. During cutaneous immune responses, Tregs constituted the major emigrants and inhibited immune responses more robustly than did LN-resident Tregs. We consistently observed that cutaneous immune responses were prolonged by depletion of endogenous Tregs in vivo. In addition, the circulating Tregs specifically included activated CD25hi Tregs that demonstrated a strong inhibitory function. Together, our results suggest that Tregs in circulation infiltrate the periphery, traffic to DLNs, and then recirculate back to the skin, contributing to the downregulation of cutaneous immune responses.
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KIT masters mast cells in kids, too.
J. Invest. Dermatol.
PUBLISHED: 02-11-2010
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Adult mastocytosis is usually persistent and caused by c-KIT codon 816-activating mutations. Pediatric mastocytosis is often transient, and the molecular mechanism driving mast cell proliferation in pediatric cases remains unclear. In this issue, Bodemer et al. report novel c-KIT mutations in a large percentage of pediatric cases, identifying both similarities and fundamental differences in the mechanisms causing adult and pediatric mastocytosis.
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Tumor cell expression of programmed cell death-1 ligand 1 is a prognostic factor for malignant melanoma.
Cancer
PUBLISHED: 02-10-2010
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: Melanoma tends to be refractory to various immunotherapies because of tumor-induced immunosuppression. To investigate the mechanism underlining the immunosuppression of melanoma patients, the authors focused on programmed cell death-1 (PD-1)/PD-1 ligand 1 (PD-L1) interaction between tumor cells and T cells.
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Sustained exogenous expression of therapeutic levels of IFN-gamma ameliorates atopic dermatitis in NC/Nga mice via Th1 polarization.
J. Immunol.
PUBLISHED: 01-27-2010
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The short in vivo half-life of IFN-gamma can prevent the cytokine from inducing immunological changes that are favorable for the treatment of Th2-dominant diseases, such as atopic dermatitis. To examine whether a sustained supply of IFN-gamma is effective in regulating the balance of Th lymphocyte subpopulations, plasmid vector encoding mouse IFN-gamma, pCpG-Mugamma, or pCMV-Mugamma was injected into the tail vein of NC/Nga mice, a model for human atopic dermatitis. A single hydrodynamic injection of a CpG motif reduced pCpG-Mugamma at a dose of 0.14 microg/mouse resulted in a sustained concentration of IFN-gamma in the serum, and the concentration was maintained at >300 pg/ml over 80 d. The pCpG-Mugamma-mediated IFN-gamma gene transfer was associated with an increase in the serum concentration of IL-12, reduced production of IgE, and inhibition of mRNA expression of IL-4, -5, -10, -13, and -17 and thymus and activation-regulated chemokine in the spleen. These immunological changes were not clearly observed in mice receiving two injections of 20 microg pCMV-Mugamma, a CpG-replete plasmid DNA, because of the transient nature of the expression from the vector. The mice receiving pCpG-Mugamma showed a significant reduction in the severity of skin lesions and in the intensity of their scratching behavior. Furthermore, high transepidermal water loss, epidermal thickening, and infiltration of lymphocytes and eosinophils, all of which were obvious in the untreated mice, were significantly inhibited. These results indicate that an extraordinary sustained IFN-gamma expression induces favorable immunological changes, leading to a Th1-dominant state in the atopic dermatitis model.
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The role of regulatory T cells in contact hypersensitivity.
Recent Pat Inflamm Allergy Drug Discov
PUBLISHED: 01-26-2010
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Regulatory T cells (Tregs) are one of the T cell subsets that have strong immune-suppressive activity. Contact hypersensitivity (CHS), clinically manifested as contact dermatitis, is one of the most frequently used mouse models to address cutaneous immune responses, and is composed of two phases: sensitization and elicitation. Recently, the role of Tregs in CHS has been investigated using newly generated genetically engineered mice. In this review, we will provide an overview of recent patents and the mechanism of Treg-mediated immunosuppression especially in terms of IL-10, CD39, CTLA-4, and RANKL, and discuss the role of Tregs in CHS during the sensitization and elicitation phases.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.