Publications by authors named "Hajime Suto"

Mast cells (MCs) are tissue-resident cells of hematopoietic origin that play an important role in host's defense mechanism against nematodes. However, excessive activation of these cells contributes to the development of certain allergic diseases. Immunoglobin E (IgE) is one of the well-known molecules that activate MCs.

View Article and Find Full Text PDF

High-frequency spectroscopy (HFS) is an analytical method that is sensitive to slight changes in the dielectric properties of materials. Since water has high permittivity, HFS can be used to detect changes in water content in materials. In this study, we employed HFS to measure human skin moisture during a water sorption-desorption test.

View Article and Find Full Text PDF

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by type 2 immune responses. Interleukin-25 (IL-25) is produced predominantly by epithelial cells. It can activate Th2 cells to produce type 2 cytokines such as IL-4, IL-5 and IL-13, contributing to host defense against nematodes.

View Article and Find Full Text PDF

Introduction: Repeated skin contact to detergents causes chronic irritant contact dermatitis (ICD) associated with itch sensation and eczema. However, the mechanisms of detergent-induced ICD are poorly understood. Here, we established a new murine model of detergent-induced ICD with H1-antihistamine-refractory itch.

View Article and Find Full Text PDF

Exposure to various antigens derived from house dust mites (HDM) is considered to be a risk factor for development of certain allergic diseases such as atopic asthma, atopic dermatitis, rhinitis and conjunctivitis. Chitin is an insoluble polysaccharide (β-(1-4)-poly-N-acetyl-D-glucosamine) and a major component in the outer shell of HDMs. Mice exposed to chitin develop asthma-like airway eosinophilia.

View Article and Find Full Text PDF

Silica crystals (silica), which are a major mineral component of volcanic ash and desert dust, contribute to the pathogenesis of pulmonary disorders such as asthma and fibrosis. Although administration of silica or sand dust to rodents exacerbates development of ovalbumin-induced or house dust mite-induced asthma-like airway inflammation, the detailed mechanisms remain unclear. Here, using murine models, we found that silica can induce IL-33 expression in pulmonary epithelial cells.

View Article and Find Full Text PDF

IL-25, a member of the IL-17 family of cytokines, is known to enhance type 2 immune responses, but suppress type 3 (IL-17A)-mediated immune responses. Mice deficient in IL-1 receptor antagonist (Il1rn mice) have excessive IL-1 signaling, resulting in spontaneous development of IL-1-, TNF- and IL-17A-dependent aortitis. We found that expression of II25 mRNA was increased in the aortae of Il1rn mice, suggesting that IL-25 may suppress development of IL-1-, TNF- and IL-17A-dependent aortitis in Il1rn mice by inhibiting type 3-mediated immune responses.

View Article and Find Full Text PDF
Article Synopsis
  • Certain proteases from house dust mites and plants can trigger allergic airway inflammation by breaking down tight junctions between epithelial cells, resulting in airway eosinophilia in mice.
  • This study shows that inhalation of Aspergillus-derived proteases leads to airway eosinophilia through protease-activated receptor-2 (PAR2), highlighting their role over other cell receptors.
  • The eosinophilia is primarily mediated by innate immune cells rather than T, B, or NKT cells, with IL-33 being crucial for this response.
View Article and Find Full Text PDF
Article Synopsis
  • Chitin, a component found in house dust mites, fungi, and crustaceans, can activate immune cells and contribute to allergic conditions like asthma.
  • Research shows that when mice were exposed to chitin alongside ovalbumin (OVA), their airway inflammation worsened due to IL-33, a signaling protein.
  • Chitin enhances IL-33-driven IL-1β production in dendritic cells, leading to increased activation of Th2 cells, which exacerbates allergy-related airway inflammation and suggests new therapeutic avenues for treating allergic disorders.
View Article and Find Full Text PDF

Background: In addition to thymic stromal lymphopoietin and IL-33, IL-25 is known to induce T2 cytokine production by various cell types, including T2 cells, T9 cells, invariant natural killer T cells, and group 2 innate lymphoid cells, involved in T2-type immune responses. Because both T2-type and T17-type cells/cytokines are crucial for contact hypersensitivity (CHS), IL-25 can contribute to this by enhancing T2-type immune responses. However, the precise role of IL-25 in the pathogenesis of fluorescein isothiocyanate-induced CHS is poorly understood.

View Article and Find Full Text PDF

Interleukin (IL)-25, which is a member of the IL-17 family of cytokines, induces production of such Th2 cytokines as IL-4, IL-5, IL-9 and/or IL-13 by various types of cells, including Th2 cells, Th9 cells and group 2 innate lymphoid cells (ILC2). On the other hand, IL-25 can suppress Th1- and Th17-associated immune responses by enhancing Th2-type immune responses. Supporting this, IL-25 is known to suppress development of experimental autoimmune encephalitis, which is an IL-17-mediated autoimmune disease in mice.

View Article and Find Full Text PDF

Introduction: Pathological changes of severe chronic allergic conjunctivitis are driven not only via acquired immunity but also via innate immunity. Type 2 immune response-initiating cytokines may play some roles as innate immunity-dependent components of the ocular surface inflammation. To investigate the involvement of type 2 immune response-initiating cytokines in innate immunity-dependent, papain-induced conjunctival inflammation model using IL-25-, IL-33-, and TSLP receptor (TSLPR)-knockout (KO) mice with reference to basophils and ILC2.

View Article and Find Full Text PDF

Protease activity of papain, a plant-derived occupational allergen homologous to mite major allergens, is essential to IgE/IgG1 production and lung eosinophilia induced by intranasal papain administration in mice, and IL-33 contributes to these responses. In this work, we investigate skin and Ab responses induced by s.c.

View Article and Find Full Text PDF

IL-25, IL-33 and TSLP, which are produced predominantly by epithelial cells, can induce production of Th2-type cytokines such as IL-4, IL-5 and/or IL-13 by various types of cells, suggesting their involvement in induction of Th2-type cytokine-associated immune responses. It is known that Th2-type cytokines contribute to host defense against malaria parasite infection in mice. However, the roles of IL-25, IL-33 and TSLP in malaria parasite infection remain unclear.

View Article and Find Full Text PDF

Purpose: To clarify the possible involvement of the type 2-initiating cytokines interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP) in the pathophysiology of allergic conjunctivitis, we evaluated ragweed (RW)-induced experimental allergic conjunctivitis (EAC) models by using IL-25 knockout (KO), IL-33 KO, and TSLP receptor (TSLPR) KO mice.

Methods: Interleukin-25 KO, IL-33 KO, TSLPR KO, and BALB/c wild-type mice were sensitized twice with RW in alum and then challenged with RW in eye drops. Clinical scores and eosinophil infiltration were evaluated.

View Article and Find Full Text PDF

Background: IL-25, IL-33 and TSLP are produced predominantly by epithelial cells and are known to induce Th2-type cytokines. Th2-type cytokines are involved not only in host defense against nematodes, but also in the development of Th2-type allergic diseases. TSLP was reported to be crucial for development of allergic airway inflammation in mice after inhalation of allergens to which they had been sensitized epicutaneously (EC) beforehand.

View Article and Find Full Text PDF

House dust mite-derived proteases contribute to allergic disorders in part by disrupting epithelial barrier function. Interleukin-33 (IL-33), produced by lung cells after exposure to protease allergens, can induce innate-type airway eosinophilia by activating natural helper (NH) cells, a member of group 2 innate lymphoid cells (ILC2), to secrete Th2 type-cytokines. Because IL-33 also can induce mast cells (MCs) to secrete Th2 type-cytokines, MCs are thought to cooperate with NH cells in enhancing protease or IL-33-mediated innate-type airway eosinophilia.

View Article and Find Full Text PDF
Article Synopsis
  • Epidermal hyperplasia is a key characteristic in both atopic dermatitis and psoriasis, and this study investigates the role of periostin, a protein previously linked to atopic dermatitis, in psoriasis-related hyperplasia.
  • The study involved immunohistochemical analysis of skin biopsies from psoriasis patients and the use of periostin-deficient mice in an imiquimod-induced psoriasis model to assess periostin's role.
  • Results showed that periostin is significantly expressed in psoriasis patients and is crucial for epidermal hyperplasia, but its influence occurs independently of key inflammatory pathways typically involved in psoriasis, suggesting it is a common mediator in skin inflammation across both conditions.
View Article and Find Full Text PDF

Glutamate plays an important role in skin barrier signaling. In our previous study, Yokukansan (YKS) affected glutamate receptors in NC/Nga mice and was ameliorated in atopic dermatitis lesions. The aim of this study was to assess the effect of YKS on skin and cultured human keratinocytes.

View Article and Find Full Text PDF

IL-17RA is a shared receptor subunit for several cytokines of the IL-17 family, including IL-17A, IL-17C, IL-17E (also called IL-25) and IL-17F. It has been shown that mice deficient in IL-17RA are more susceptible to sepsis than wild-type mice, suggesting that IL-17RA is important for host defense against sepsis. However, it is unclear which ligands for IL-17RA, such as IL-17A, IL-17C, IL-17E/IL-25 and/or IL-17F, are involved in the pathogenesis of sepsis.

View Article and Find Full Text PDF

Both interleukin (IL)-33 and IL-25 induce Th2 cytokine production by various cell types, suggesting that they contribute to development of allergic disorders. However, the precise roles of IL-33 and IL-25 in house dust mite (HDM)-induced allergic rhinitis (AR) remain unclear. Both IL-33 and IL-25 were produced mainly by nasal epithelial cells during HDM-induced AR.

View Article and Find Full Text PDF

How the innate and adaptive immune systems cooperate in the natural history of allergic diseases has been largely unknown. Plant-derived allergen, papain, and mite allergens, Der f 1 and Der p 1, belong to the same family of cysteine proteases. We examined the role of protease allergens in the induction of Ab production and airway inflammation after repeated intranasal administration without adjuvants and that in basophil/mast cell stimulation in vitro.

View Article and Find Full Text PDF

IL-17A, IL-17F, and IL-25 are ligands for IL-17RA. In the current study, we demonstrated that IL-25-deficient mice-but not IL-17A-, IL-17F-, IL-17A/F-, IL-23p19-, or retinoic acid-related orphan receptor (ROR)-γt-deficient mice-showed significant suppression of 1) the number of eosinophils and the levels of proinflammatory mediators in bronchoalveolar lavage fluids, 2) airway hyperresponsiveness to methacholine, and 3) OVA-specific IgG1 and IgE levels in the serum during OVA-induced Th2-type/eosinophilic airway inflammation. The IL-25 deficiency did not affect lung dendritic cell migration or Ag-specific memory-Th2 cell expansion during Ag sensitization.

View Article and Find Full Text PDF

Background: IL-33 is known to induce Th2-type cytokine production by various types of cells through its receptors, ST2 and IL-1RAcP. Polymorphism in the ST2 and/or IL-33 genes was found in patients with atopic dermatitis and asthma, implying that the IL-33/ST2 pathway is closely associated with susceptibility to these diseases. Exposure to allergens through damaged skin is suspected to be a trigger for allergen sensitization, resulting in development of such allergic disorders as asthma and atopic dermatitis.

View Article and Find Full Text PDF