Publications by authors named "Kyoko Oh-oka"

Psoriasis is a chronic inflammatory skin disease. IL-23 plays a critical role in its pathogenesis by inducing production of IL-17A from pathological Th17 cells and IL-17A-producing γδ T cells. However, the mechanisms regulating the IL-23/IL-17 axis in psoriasis are incompletely understood.

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Psoriasis is a chronic inflammatory skin disease. IL-23 plays a critical role in its pathogenesis by inducing production of IL-17A from pathological Th17 cells and IL-17A-producing γδ T cells. However, the mechanisms regulating the IL-23/IL-17 axis in psoriasis are incompletely understood.

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DNAM-1 is an activating immunoreceptor expressed on hematopoietic cells, including both CD4 and CD8 T cells, natural killer cells, and platelets. Since DNAM-1 is involved in the pathogenesis of various inflammatory diseases and cancers in humans as well as mouse models, it is a potential target for immunotherapy for these diseases. In this study, we generated a humanized neutralizing antihuman DNAM-1 monoclonal antibody (mAb), named TNAX101A, which contains an engineered Fc portion of human IgG1 to reduce Fc-mediated effector functions.

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Article Synopsis
  • Interleukin-33 (IL-33) and its receptor ST2 are key players in activating mast cells, which are implicated in allergic diseases.
  • Resveratrol, a natural compound, has been found to inhibit mast cell activation triggered by IL-33 and also reduces the production of inflammation-related cytokines like IL-6 and TNF-α.
  • The mechanism of action indicates that resveratrol targets the MK2/3-PI3K/Akt pathway, providing a potential therapeutic approach for treating various allergic conditions.
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  • Interleukin-17-producing CD4 T helper (Th17) cells play a crucial role in defending against bacterial and fungal infections in the small intestine.
  • Research shows that the number of Th17 cells varies throughout the day, influenced by the circadian rhythm, while this variation is absent in mice with a mutated circadian gene or in abnormal light conditions.
  • The findings highlight the importance of CCL20, a chemokine related to Th17 cell movement, in regulating these daily fluctuations, suggesting potential for improving mucosal vaccination strategies.
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  • Mesalamine, a key medication used to treat inflammatory bowel diseases, may work by enhancing the growth of regulatory T cells (Tregs) in the colon, but its exact mechanisms aren't fully understood.
  • In experiments with different types of mice, mesalamine was shown to increase Treg accumulation and also activated specific pathways involving the aryl hydrocarbon receptor (AhR) and transforming growth factor (TGF)-β.
  • The study suggests that mesalamine’s anti-inflammatory effects in colitis are linked to the boost in Tregs through the AhR pathway, which then activates TGF-β, offering a new perspective on how this drug works.
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OBJECT Indoleamine 2,3-dioxygenase (IDO), a key enzyme of tryptophan (Trp) metabolism, is involved in tumor-derived immune suppression through depletion of Trp and accumulation of the metabolite kynurenine, resulting in inactivation of natural killer cells and generation of regulatory T cells (Tregs). It has been reported that high expression of IDO in cancer cells is associated with suppression of the antitumor immune response and is consistent with a poor prognosis. Thus, IDO may be a therapeutic target for malignant cancer.

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  • Maternal milk contains transforming growth factor (TGF-β), which is important for infants' immune system development, but the factors influencing its levels are not fully understood.
  • This study compared TGF-β2 levels in the colostrum of lactating women from Japan and Nepal, examining how hygiene standards affected these levels.
  • The findings indicated that Japanese women had higher TGF-β levels in breast milk compared to Nepalese women, with factors such as animal milk consumption and family size influencing TGF-β expression.
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Background & Aims: The circadian clock drives daily rhythms in behavior and physiology. A recent study suggests that intestinal permeability is also under control of the circadian clock. However, the precise mechanisms remain largely unknown.

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  • The aryl hydrocarbon receptor (AhR) is traditionally known for detoxifying environmental toxins but is now recognized for its role in regulating inflammation, particularly in inflammatory bowel diseases (IBDs).
  • A study identified 1,4-dihydroxy-2-naphthoic acid (DHNA), found in certain bacteria from Swiss cheese, as an effective AhR activator that could potentially help treat IBD.
  • DHNA not only triggers the AhR pathway, enhancing gut health and reducing colitis in mice, but it also suggests that AhR might serve as a crucial link between diet, gut bacteria, and overall intestinal health.
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  • * Mice consuming resveratrol showed significantly reduced allergy symptoms, including lower production of IgE antibodies and less severe immune responses following allergy sensitization.
  • * The study suggests that resveratrol may work by inhibiting the maturation of dendritic cells and altering T cell activation pathways, providing insight into its possible therapeutic role against food allergies.
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Background: Cytokines in breast milk may play crucial roles in the beneficial effects of breastfeeding in protecting against allergic and infectious diseases in infants. In particular, breast milk-borne transforming growth factor-beta (TGF-β) has an important potential role in developing the mucosal immune system in infants. However, little is known about what factors influence TGF-β expression in human milk.

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Atg8 and its mammalian homolog LC3, ubiquitin-like proteins (Ubls) required for autophagosome formation, are remarkably unique in that their conjugation target is the lipid phosphatidylethanolamine (PE). Although PE was identified as the sole lipid conjugated with Atg8/LC3 in vivo, phosphatidylserine (PS) can be also a good substrate for its conjugation reaction in vitro. This posed a simple, intriguing question: What confers substrate specificity to lipidation of Atg8/LC3 in vivo? Our recent in vitro studies propose that intracellular milieus such as cytosolic pH and acidic phospholipids in membranes significantly contribute to selective production of the Atg8-PE conjugate.

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Yeast Atg8 and its mammalian homolog LC3 are ubiquitin-like proteins involved in autophagy, a primary pathway for degradation of cytosolic constituents in vacuoles/lysosomes. Whereas the lipid phosphatidylethanolamine (PE) was identified as the sole in vivo target of their conjugation reactions, in vitro studies showed that the same system can mediate the conjugation of these proteins with phosphatidylserine as efficiently as with PE. Here, we show that, in contrast to PE conjugation, the in vitro phosphatidylserine conjugation of Atg8 is markedly suppressed at physiological pH.

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