Yasuhiro Hayashi

Asubio Pharma Co., Ltd., Kōbe, Hyōgo, Japan

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Publications (10)22.55 Total impact

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    ABSTRACT: This paper describes the design, synthesis, and biological evaluation of new indole-based cytosolic phospholipase A2α (cPLA2α, a group IVA phospholipase A2) inhibitors. A screening-hit compound from our library, (E)-3-{4-[(4-chlorophenyl)thio]-3-nitrophenyl}acrylic acid (5), was used to design a class of 3-(1-aryl-1H-indol-5-yl)propanoic acids as new small molecule inhibitors. The resultant structure-activity relationships studied using the isolated enzyme and by cell-based assays revealed that the 1-(p-O-substituted)phenyl, 3-phenylethyl, and 5-propanoic acid groups on the indole core are essential for good inhibitory activity against cPLA2α. Optimization of the p-substituents on the N1 phenyl group led to the discovery of 56n (ASB14780), which was shown to be a potent inhibitor of cPLA2α via enzyme assay, cell-based assay, and guinea pig and human whole-blood assays. It displayed oral efficacy toward mice tetradecanoyl phorbol acetate-induced ear edema and guinea pig ovalbumin-induced asthma models.
    Journal of medicinal chemistry. 08/2014;
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    ABSTRACT: Inflammation is a fundamental defensive response to harmful stimuli. However, it can cause damage if it does not subside. To avoid such damage, organisms have developed a mechanism called resolution of inflammation. Here we applied an untargeted metabolomics approach to a sterile and self-resolving animal model of acute inflammation, namely zymosan-induced peritonitis in mice, to examine the effect of inflammation and resolution on the metabolomic profiles. Significant and time-dependent changes in metabolite profiles after zymosan administration were observed in both peritoneal wash fluid (PWF) and plasma. These metabolomic changes correlated well with inflammatory chemokine or cytokine production. In PWF, most of metabolites that could detected increased in zymosan-treated mice, which is suggestive of inflammation, oxidative stress and increased energy demands. In plasma, most metabolites in the central metabolic pathway (glycolysis and TCA cycle) were significantly downregulated after zymosan administration. The concentration of the ketone body 3-hydroxybutyric acid (3-HB) in plasma and PWF increased in zymosan-injected animals indicating upregulation of fatty acid β-oxidation. Increased 3-HB level was observed in the cells that infiltrated into the peritoneal cavity and these infiltrated cells might contribute, at least in part, to the production of 3-HB in the peritoneal cavity.
    PLoS ONE 01/2013; 8(6):e66270. · 3.53 Impact Factor
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    ABSTRACT: Excessive proliferation of epidermal keratinocytes is a typical aspect of chronic skin diseases such as psoriasis. In the present study, the effect of phosphodiesterase 7A (PDE7A) inhibitor ASB16165 on proliferation of keratinocytes was investigated to examine the role of PDE7A in keratinocyte proliferation and the possible therapeutic relevance of PDE7A inhibition in psoriasis. Topical application of ASB16165 inhibited the increase of thickness of skin as well as epidermis in a skin inflammation model induced by repeated painting of 12-O-tetradecanoylphorbol-13-acetate (TPA) in a concentration-dependent manner. The ASB16165 treatment also suppressed the increase in the number of Ki67-positive keratinocytes in the model, showing the disturbance of keratinocyte proliferation by the treatment. In addition, both ASB16165 and dibutyryl cAMP significantly decreased the proliferation of human keratinocytes in vitro, suggesting that PDE7A participates in keratinocyte proliferation probably by controlling intracellular cAMP, while the contribution of other mechanism(s) is not completely denied. The findings in the present study indicate that the effect of ASB16165 on skin and epidermal hyperplasia in the TPA-induced skin inflammation is mediated, at least in part, by the inhibition of keratinocyte proliferation. The inhibitors for PDE7A including ASB16165 might be useful for the treatment of psoriasis.
    European journal of pharmacology 05/2010; 633(1-3):93-7. · 2.59 Impact Factor
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    ABSTRACT: An intravenous injection of Concanavalin A (Con A) elevated the serum level of alanine aminotransferase (ALT) activity, a marker for liver damage, and an oral administration of PDE7A inhibitor SUN11817 suppressed the increase of ALT activity in a dose-dependent manner. Histological analysis revealed that Con A injection caused extensive liver damage, and that the SUN11817 treatment improved the degenerative change in the liver. In addition, SUN11817 inhibited not only the production of IL-4 and TNF-alpha in the Con A-induced hepatitis model but also that in vitro by murine splenocytes stimulated with alpha-galactosylceramide, an activator specific for NKT cells. The Con A injection to mice also induced expression of Fas ligand (FasL) on NKT cells, which was significantly prevented by SUN11817. As NKT cells are known to contribute to the pathogenesis in Con A-induced hepatitis by producing cytokines such as IL-4 and TNF-alpha and inducing FasL-mediated hepatocyte injury, it is thought that PDE7A inhibitor SUN11817 improves liver injury in the Con A model by blocking cytokine production and FasL expression in NKT cells. PDE7A might be a novel pharmaceutical target for hepatitis.
    International immunopharmacology 09/2009; 9(11):1347-51. · 2.21 Impact Factor
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    ABSTRACT: A possible involvement of phosphodiesterase 7A (PDE7A) in proliferation and function of NKT cells was examined using ASB16165, a selective inhibitor for PDE7A. Stimulation of isolated murine NKT cells with anti-CD3 antibody plus IL-2 induced not only cell proliferation but production of cytokines including IFN-gamma, TNF-alpha, IL-17 and IL-22. ASB16165 significantly inhibited the CD3/IL-2-stimulated cell proliferation and production of all the cytokines examined. Forskolin (an activator of adenylyl cyclase) and dibutyryl cAMP also exerted inhibitory effects on the cell proliferation and cytokine production of NKT cells. In addition, Rp-8-Br-cAMPS, an inhibitor of protein kinase A (PKA), reversed the suppressive effects of ASB16165 against NKT cells. These results suggest that PKA/cAMP as well as PDE7A is involved in regulation of cell proliferation and cytokine production of NKT cells, and that the inhibitory effects of ASB16165 in NKT cells shown here are mediated by increase in cellular cAMP level. Our findings also raise the possibility that PDE7A inhibitor including ASB16165 may be useful for treatment of the diseases in which NKT cells have pathogenic roles.
    Cellular Immunology 06/2009; 258(2):147-51. · 1.74 Impact Factor
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    ABSTRACT: Possible role of phosphodiesterase 7A (PDE7A) in skin inflammation was examined using ASB16165, a specific inhibitor for PDE7A. Epicutaneous application of phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) to mouse ear resulted in induction of skin edema, and topical treatment with ASB16165 inhibited the induction of skin edema in a dose-dependent manner. The TPA challenge also increased the level of TNF-alpha at the application site, and the ASB16165 treatment reduced the TNF-alpha level in the skin. In addition, ASB16165 suppressed the production of TNF-alpha by human keratinocytes stimulated in vitro with TPA and calcium ionophore. Forskolin, an activator of adenylyl cyclase, as well as dibutyryl cAMP also showed inhibitory effect on the TNF-alpha production in the cells, suggesting involvement of cAMP in TNF-alpha generation. These results demonstrate that PDE7A might regulate TNF-alpha production in keratinocytes in a cAMP-dependent fashion. As immunostaining analysis revealed that PDE7A is expressed in the epidermis and TNF-alpha is known to contribute to the TPA-induced edema, it is possible that the inhibitory effect of ASB16165 on skin edema in mouse TPA-induced dermatitis model is mediated by suppression of TNF-alpha production. This is the first report suggesting the association of PDE7A with the function of keratinocytes. ASB16165 will be useful as an agent for skin inflammation in which TNF-alpha plays a pathogenic role (e.g. psoriasis).
    European journal of pharmacology 05/2009; 613(1-3):163-6. · 2.59 Impact Factor
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    ABSTRACT: Phosphodiesterase 7A (PDE7A) has been suggested to be involved in activation of T lymphocytes. In the present study, a possible involvement of PDE7A in function of preactivated T cells (i.e. T lymphoblasts) was investigated using ASB16165, an inhibitor for PDE7A. ASB16165, which has an IC50 value of 15 nM for human PDE7A, suppressed IL-12-induced IFN-gamma production by T lymphoblasts which have been prepared by stimulating mouse T cells with anti-CD3 antibody. In the same experiment, rolipram, a PDE4-specific inhibitor, showed similar effect, while calcineurin antagonist FK506 did not. Forskolin (an adenylyl cyclase activator) and dibutyryl cAMP also inhibited the IL-12-induced IFN-gamma synthesis. Rp-8-Br-cAMPS, an inhibitor of protein kinase A (PKA), reduced the suppressive effect of ASB16165 on the IFN-gamma production by T lymphoblasts. The rescue of IFN-gamma production by Rp-8-Br-cAMPS was also observed in the inhibition by rolipram and forskolin. These findings suggest that PDE7A may regulate function of activated T cells in a cAMP/PKA-dependent manner, and that PDE4 might share the role. The data in our study also indicate that PDE7 inhibitors such as ASB16165 will be beneficial for the patients with immunological disorders.
    Immunology letters 03/2009; 122(2):193-7. · 2.91 Impact Factor
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    ABSTRACT: In the present study, possible role of phosphodiesterase 7 (PDE7) in development and function of cytotoxic T lymphocyte (CTL) was examined using ASB16165, a specific inhibitor for PDE7. ASB16165 inhibited generation of CTL activity in mixed lymphocyte reaction (MLR), in which splenocytes from C57BL/6N mice were stimulated with those from BALB/c mice. Flow cytometric analysis revealed that ASB16165 suppressed induction of activated CD4+ as well as CD8+ T cells in MLR. In cell division analyses using 5-carboxyfluorescein diacetate succinimide ester (CFSE), ASB16165 was shown to markedly inhibit proliferation of CD4+ and CD8+ T cells. In addition, ASB16165 reduced effector function of CTL, while the effect was less than that observed in CTL induction in MLR. Forskolin and dibutyryl cAMP also inhibited both the induction and effector function of CTL. PDE4 inhibitor rolipram showed similar but weaker inhibition for the development and proliferation of CD8+ T cells compared with ASB16165, and failed to impair effector function of CTL. These findings suggest that PDE7 but not PDE4 has the major role in induction and function of CTL in mice, and that the effect might be mediated by elevation of intracellular cAMP level. ASB16165 may be useful for treatment of the diseases in which CTL has a pathogenic role (e.g. autoimmune diseases).
    International Immunopharmacology 12/2008; 9(1):97-102. · 2.42 Impact Factor
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    ABSTRACT: Mast cell chymase is known to induce eosinophil migration in vivo and in vitro. In the present study, we investigated possible involvement of mitogen-activated protein (MAP) kinases; extracellular signal-regulated kinase (ERK), c-Jun amino-terminal kinase (JNK), and p38, in the chymase-induced eosinophil migration. Human chymase induced a rapid phosphorylation of ERK1/2 and p38 in human eosinophilic leukemia EoL-1 cells, while no phosphorylation was detected in JNK. The chymase-induced phosphorylation of ERK and p38 was inhibited by pertussis toxin. Similar results were obtained in the experiments using mouse chymase and eosinophils. U0126 (the inhibitor for MAP/ERK kinase) suppressed chymase-induced migration of EoL-1 cells and mouse eosinophils. However, SB203580 (p38 inhibitor) and SP600125 (JNK inhibitor) showed little effect on the migration. It is suggested therefore that chymase activates ERK and p38 probably through G-protein-coupled receptor, and that ERK but not p38 cascade may have a crucial role in chymase-induced migration of eosinophils.
    Biochemical and Biophysical Research Communications 08/2005; 332(4):969-75. · 2.28 Impact Factor
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    ABSTRACT: Interleukin-10 (IL-10), a potent antiinflammatory and immunosuppressive cytokine, plays an important role in the regulation of immune responses. To discover small molecules that stimulate IL-10 production, a cell-based screening assay was performed using a murine macrophage cell line, RAW264.7. Imidocarb, (3,3'-bis-2-imidazolin-2-yl)-carbanilide, which has been used as an anti-protozoan drug for the prevention and treatment of babesiosis in cattle, was thus identified. Imidocarb markedly enhanced LPS-induced IL-10 production not only by RAW264.7 cells but also by murine peritoneal macrophages in a concentration-dependent manner. It also augmented IL-10 production in the presence of zymosan, a yeast cell wall component. In contrast, imidocarb inhibited LPS-induced tumor necrosis factor (TNF)-alpha production by peritoneal macrophages. In mice, intraperitoneal administration of imidocarb significantly increased serum IL-10 levels and lowered TNF-alpha levels. Our results suggest that a novel anti-inflammatory property of imidocarb could lead to new therapeutic approaches in inflammatory conditions.
    Biochemical and Biophysical Research Communications 10/2003; 309(2):414-8. · 2.28 Impact Factor