Ryoji Tsuboi

Nihon Nohyaku Co., Ltd.

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Publications (345)

  • Article · Jul 2016 · Allergology International
  • [Show abstract] [Hide abstract] ABSTRACT: We previously reported a positive feedback loop between S100A8/A9 and pro-inflammatory cytokines mediated by extracellular matrix metalloproteinase inducer (EMMPRIN), an S100A9 receptor. Here, we identify neuroplastin-β (NPTNβ) as an unreported S100A8 receptor. NPTNβ and EMMPRIN form homodimers and a heterodimer, and are co-localized on the surface of cultured normal human keratinocytes (NHK). Knockdown of both receptors suppressed cell proliferation and pro-inflammatory cytokine induction. Upon stimulation with S100A8, NPTNβ recruited Grb2 and activated ERK, resulting in keratinocyte proliferation. Keratinocyte proliferation in response to inflammatory stimuli was accelerated in involucrin promoter-driven S100A8 transgenic mice. Further, S100A8 and S100A9 were strongly up-regulated and co-localized in lesional skin of atopic dermatitis patients. Our results indicate that NPTNβ and EMMPRIN form a functional heterodimeric receptor for S100A8/A9 heterodimer, followed by recruitment of specific adaptor molecules Grb2 and TRAF2, and this signaling pathway is involved in activation of both keratinocyte proliferation and skin inflammation in atopic skin. Suppression of this pathway might have potential for treatment of skin diseases associated with chronic inflammation such as atopic dermatitis.
    Article · Jul 2016 · Journal of Investigative Dermatology
  • K Harada · A Iwasaki · Y Kato · [...] · R Tsuboi
    Article · Jun 2016 · Clinical and Experimental Dermatology
  • [Show abstract] [Hide abstract] ABSTRACT: Seborrheic dermatitis (SD) is a chronic inflammatory dermatologic condition, in which erythema and itching develop on areas of the body with sebaceous glands, such as the scalp, face, and chest. The inflammation is evoked directly by oleic acid, which is hydrolyzed from sebum by lipases secreted by skin microorganisms. Although the skin fungal genus, Malassezia, is thought to be the causative agent of SD, analysis of the bacterial microbiota of skin samples of SD patients is necessary to understand their interactions with Malassezia because the skin microbiota comprises diverse bacterial and fungal genera. In the present study, we analyzed bacterial microbiota at non-lesional and lesional sites of 24 patients with SD by pyrosequencing and qPCR. Principal coordinate analysis revealed clear separation between the microbiota of non-lesional and lesional sites. Acinetobacter, Corynebacterium, Staphylococcus, Streptococcus, and Propionibacterium were abundant at both sites. Propionibacterium was abundant at non-lesional sites, whereas Acinetobacter, Staphylococcus, and Streptococcus predominated at lesional sites; however, the level of Propionibacterium colonization did not differ significantly between lesional and non-lesional sites by qPCR. As these abundant bacteria hydrolyze sebum, they might contribute to SD development in addition to Malassezia. This is, to the best of our knowledge, the first comprehensive analysis of the bacterial microbiota of the skin of SD patients.
    Article · Jun 2016 · Microbiology and Immunology
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    Y. Kato · C. Egusa · T. Maeda · R. Tsuboi
    Full-text Article · May 2016
  • Article · May 2016
  • Article · May 2016
  • Aya Iwasaki · Kazutoshi Harada · Tatsuo Maeda · [...] · Ryoji Tsuboi
    Article · Apr 2016 · The Journal of Dermatology
  • Masayuki Hasuko · Tetsuo Toga · Toshiya Tsunemitsu · [...] · Ryoji Tsuboi
    [Show abstract] [Hide abstract] ABSTRACT: Luliconazole (LLCZ), an imidazole derivative with a broad spectrum of potent antifungal activity especially for T. rubrum and T. mentagrophytes, is under development as a new drug for treatment of tinea unguium. It is well known that curative effect of an antifungal agent in dermatophytosis is affected by the pharmacokinetics of an agent at the infection loci as well as its antifungal activity, but there is no report about the affinity of LLCZ to nail keratin. We studied LLCZ affinity to keratin powder prepared from healthy human nail and porcine hoof. The LLCZ adsorbed to keratin preparations was washed with phosphate buffer, and its concentration in the buffer supernatant was measured by HPLC. Antifungal titer of the supernatant was also biologically confirmed by disk diffusion assay. Adsorption rate of LLCZ was 80% or more, and LLCZ was gradually liberated into washing buffer. Cumulative liberation rate in 10 times repeated washing against initially adsorbed drug amount was 47.4% for keratin from human nail and was either 52.5% or 50.8% (depending on the LLCZ concentration) for keratin from porcine hoof. The supernatant showed antifungal potential to T. rubrum. These results indicate that LLCZ applied to the nail surface is fully adsorbed to nail keratin and gradually liberated from it. The nail keratin could function as drug reservoir to supply biologically active LLCZ to the nail tissue region of infection loci. The LLCZ delivered to the loci would exert its antifungal potential on tinea unguium. This study also suggests the versatility of porcine hoof powder as an alternative to human nail keratin preparation for non-clinical study.
    Article · Mar 2016
  • [Show abstract] [Hide abstract] ABSTRACT: Androgenetic alopecia is an androgen-induced pattern of progressive hair loss, which occurs in genetically predisposed people. This study aimed to determine long-term safety, tolerability and efficacy of dutasteride 0.5 mg, an inhibitor of 5-α-reductase, in Japanese male patients with androgenetic alopecia. This was a multicenter, open-label, prospective outpatient study (clinicaltrials.gov NCT01831791, GSK identifier ARI114264) in which patients took dutasteride 0.5 mg p.o. once daily for 52 weeks. Primary end-points included adverse event assessment, incidence of drug-related adverse event and premature discontinuations. Secondary end-points included hair growth, hair restoration and global improvement in hair. A total of 120 patients were enrolled, of whom 110 completed 52 weeks of treatment. Nasopharyngitis, erectile dysfunction and decreased libido were the most frequently reported adverse events and most adverse events were mild. Drug-related adverse events were reported with an incidence of 17%, none of which led to study withdrawal. Hair growth (mean target area hair count at week 52), hair restoration (mean target area hair width at week 52) and global appearance of hair (mean of the median score at week 52) improved from baseline during the study. As a potential future treatment option for male androgenetic alopecia, dutasteride 0.5 mg exhibited long-term safety, tolerability and efficacy within this study population.
    Article · Feb 2016 · The Journal of Dermatology
  • Takashi Arai · Yukihiko Kato · Maki Funaki · [...] · Ryoji Tsuboi
    [Show abstract] [Hide abstract] ABSTRACT: Intravascular large B-cell lymphoma (IVL) is a rare subtype of extranodal malignant lymphoma. The proliferation of neoplastic B cells within small blood vessels causes eruptions and other symptoms in a variety of organs. The random skin biopsy is useful for diagnosing this condition in its early stages. In order to assess the diagnostic utility of this method, we examined 3 cases with the aim of comparing the occurrence of tumor cells in lesional and healthy-looking skin by performing a random skin biopsy of 32 separate sites. Our findings from the total of 32 biopsy specimens collected from the 3 cases indicated that 16 of the 17 sites on the lesional skin and 1 of the 15 sites on the healthy-looking skin were positive for neoplastic cells. This finding suggested that IVL cells occurred more frequently in the lesional skin than in the healthy-looking skin.
    Article · Feb 2016 · Dermatology
  • T. Kariya · Y. Kato · A. Kanzaki · [...] · R. Tsuboi
    [Show abstract] [Hide abstract] ABSTRACT: Deoxy-2-[18F] fluoro-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) is known to be highly accurate in differentiating benign from malignant lesions. In rare cases, benign tumors, viral infections, and sarcoidosis of the skin have been reported to show FDG uptake, but the mechanism remains unclear. Here we report the first documented case of seborrheic keratosis (SK) showing increased FDG uptake. FDG PET can be used to detect enhanced glycolysis of tumor cells by measuring increased levels of glucose transporters (GLUTs) indicative of higher glucose uptake. GLUT1 and GLUT3 expression in this case was compared with that in PET-negative SK and two normal skin samples using quantitative PCR with paraffin-embedded tissue. The expression of GLUT1 and GLUT3 was higher in PET-positive SK than in PET-negative SK or normal skin. More specifically, the expression of GLUT3 was observed only in the PET-positive case. This study revealed that high GLUT1 and GLUT3 expression in SK might be associated with the uptake of FDG. This article is protected by copyright. All rights reserved.
    Article · Jan 2016 · British Journal of Dermatology
  • Junichiro Hiruma · Miki Okubo · Rui Kano · [...] · Ryoji Tsuboi
    [Show abstract] [Hide abstract] ABSTRACT: Infection by Trichophyton tonsurans is an emerging fungal epidemic in Japan. Itraconazole (ITZ) and terbinafine have been used for the treatment of this infection for 15 years. However, patients with T. tonsurans infections have been shown to remain uncured or to become reinfected, suggesting that subclinical infection or polyphyletic strains and/or antifungal drug-resistant strains might be occurring in Japan. In this study, PCR analysis was performed to confirm the presence of the mating type locus MAT in genomic DNA from 60 Japanese clinical isolates of T. tonsurans, and to assess the previously postulated clonal origin of clinical isolates of this species. Antifungal susceptibility testing on isolates also was performed to confirm the absence of strains resistant to ITZ. PCR analysis proved that all 60 strains contained the MAT1-1 allele, while none contained the MAT1-2 allele. As determined by E-test, the mean MIC of ITZ in the 60 strains was 0.023 mg/L (range 0.002-0.125 mg/L). All strains of T. tonsurans isolated in Japan were clonal and were not resistant to ITZ. Therefore, dermatophytosis due to T. tonsurans is expected to respond to ITZ, since clinical isolates of T. tonsurans tested to date have been susceptible to this antifungal. This infection is proliferating as a subclinical infection in Japan.
    Article · Jan 2016 · Mycopathologia
  • Hiroyasu Koga · Yasuko Nanjoh · Tetsuo Toga · [...] · Ryoji Tsuboi
    [Show abstract] [Hide abstract] ABSTRACT: Objective: To compare drug concentrations in the stratum corneum following daily application of luliconazole and terbinafine cream in a guinea pig tinea pedis model. METHODS: Luliconazole 1% cream or terbinafine 1% cream were topically applied once daily to hind limbs of guinea pigs for 14 days. Drug concentration in stratum corneum of plantar skin was measured by HPLC-UV on days 1, 3, 7, 10, and 14. Separately, creams were applied daily for 5 days to the hind limbs of guinea pigs and skin drug release determined. In addition, drug retention in the stratum corneum was assessed by infecting guinea pigs with Trichophyton mentagrophytes, 14 and 21 days after a single application of luliconazole or terbinafine creams. RESULTS: Luliconazole stratum corneum concentrations were higher than those of terbinafine throughout the study. Concentrations of luliconazole and terbinafine were 71.6μg/g and 36.6μg/g, respectively, after a single application (P<.05), reaching steady state after 10 days. Cumulative release of luliconazole from the stratum corneum was 4.5 times greater than with terbinafine. Unlike terbinafine, no fungal invasion of the stratum corneum was seen 14 days post-treatment with luliconazole. CONCLUSIONS: Drug concentrations of luliconazole in the stratum corneum and subsequent release are greater than those achieved with terbinafine and may contribute to clinical efficacy. Luliconazole may also provide greater protection against disease recurrence. J Drugs Dermatol. 2016;15(1):104-108.
    Article · Jan 2016 · Journal of drugs in dermatology: JDD
  • Jun Maeda · Yasuko Nanjoh · Hiroyasu Koga · [...] · Ryoji Tsuboi
    [Show abstract] [Hide abstract] ABSTRACT: The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) of luliconazole against Trichophyton rubrum (14 strains) and Trichophyton mentagrophytes (14 strains), which are the most common cause of tinea, were compared with those of 6 topical antifungal drugs of lanoconazole, bifonazole, efinaconazole, liranaftate, naftifine and terbinafine. Luliconazole showed the most potent antifungal activity (MIC90 =0.00098 μg/ml and MFC90 =0.0078 μg/ml) among the compounds tested against the two species. Efinaconazole and bifonazole, the drug of azole-class, showed a large MFC/MIC ratio. On the other hand, these ratios of luliconazole and lanoconazole were as small as those of liranaftate, naftifine and terbinafine which are thought to possess fungicidal mechanism. These results suggest that luliconazole possesses fungicidal activity against both species of Trichophyton. In this study, we found that luliconazole had the most potent antifungal activity among the major topical antimycotics used in Japan and the US. Luliconazole would be the best-in-class drug for dermatophytosis in clinics.
    Article · Jan 2016
  • [Show abstract] [Hide abstract] ABSTRACT: We herein report a case of hair follicle nevus, a rare hamartoma found on the face and showing follicular differentiation, which was associated with sebaceous hyperplasia. Dermoscopy of the lesion showed yellow globules surrounded by crown vessels/telangiectasias and scattered tiny hairs. Histopathological investigation revealed hyperplasia of the sebaceous glands and proliferation of well-differentiated vellus hair follicles. These pathological findings were thought to correspond to the yellowish globules and tiny hairs observed under dermoscopy. Hair follicle nevus associated with sebaceous hyperplasia is extremely rare; however, dermoscopic examination can suggest an appropriate diagnosis. The present case proved the diagnostic usefulness of dermoscopy for cutaneous tumors with hair follicular and sebaceous glandular differentiation.
    Article · Dec 2015 · Case Reports in Dermatology
  • [Show abstract] [Hide abstract] ABSTRACT: Bleomycin-induced scleroderma in mice is an established model for human scleroderma. Making use of this, we have established a new model for wound retardation. After inducing dermal sclerosis by local bleomycin treatment in nude mice, a full-thickness wound was made by punch excision on the bleomycin application site. Mice pretreated with bleomycin showed a significant delay in wound closure, as compared with mice pretreated with phosphate-buffered saline. Proliferation of keratinocytes was significantly inhibited and the number of Ki-67-positive keratinocytes was significantly lower in the bleomycin-pretreated skin. Also, the number of CD31-positive blood vessels was markedly reduced in the bleomycin-treated skin. The topical daily application of basic fibroblast growth factor (bFGF) significantly promoted wound closure, while increasing blood vessel formation and reducing transforming growth factor-β and alpha-smooth muscle actin mRNA levels. Furthermore, only two applications of PG-FGF1, a fusion protein of FGF1 with heparan sulfate proteoglycan, overcame the delay in wound closure. Wound delay in this model mainly occurred as a result of decreased vessel formation and keratinocyte migration following bleomycin treatment. It is expected that this model will provide novel insights into the pathogenesis of wound healing and the exploration of possible candidate drugs for refractory or chronic wounds in the clinical setting.
    Article · Dec 2015 · Archives for Dermatological Research
  • Article · Nov 2015 · International journal of dermatology
  • Takafumi Numata · Tomonobu Ito · Tatsuo Maeda · [...] · Ryoji Tsuboi
    [Show abstract] [Hide abstract] ABSTRACT: Background: IL-33, a member of the IL-1 cytokine family, binds to heterodimeric receptors ST2 and IL-1 receptor accessory protein, and activates Th2-type immune responses. The signals from the ST2 receptor are mediated by the two major pathways, including AP-1 and NF-κB molecules. The present study examined whether IL-33 induced ICAM-1 expression in bone marrow-derived mast cells (BMMCs). Methods: BMMCs from C57BL/6J mice, cultured in media containing IL-3 (20 ng/ml), were treated with IL-33 (50 ng/ml) for up to 72 h. ICAM-1 expression with mRNA and protein, degranulation of siRNA ICAM-1 transfected BMMCs, and cell adhesion were analyzed. In the in vivo part of the experiment rIL-33 (500 ng) was injected intradermally into the ear pinnae of mice and any resulting pathological changes were assessed. Results: ICAM-1 mRNA expression was increased one hour after IL-33 stimulation while ICAM-1 protein attained maximum expression levels 24 h after IL-33 stimulation. Moreover, IL-33-treated BMMCs showed increased cell adhesion to the LFA-1-coated plate. However, siRNA ICAM-1 transfected BMMCs did not affect Ag/IgE-mediated degranulation level compared to the wild control siRNA. Pre-treatment with a NF-κB inhibitor dramatically reduced ICAM-1 expression in IL-33-treated BMMCs, suggesting the involvement of NF-κB in the process. In vivo study, at 6 h after IL-33 treatment, MCs histologically showed up-regulated ICAM-1 expression though the number of tryptase-positive cells did not change. Conclusions: These data suggest that MCs increase ICAM-1 expression and activate LFA-1 positive cells in the early phase of skin inflammation in response to IL-33.
    Article · Nov 2015 · Allergology International
  • Yukihiko Kato · Chizu Egusa · Tatsuo Maeda · Ryoji Tsuboi
    [Show abstract] [Hide abstract] ABSTRACT: Background: Retinoids exert anti-proliferative, differentiative, and apoptosis-inducing effects through their receptors. Retinoic acid receptor (RAR) β2 behaves as a tumor suppressor gene, and its expression is suppressible by DNA methylation in many malignancies. Objective: We aimed to determine whether combining a retinoid, Am 80, with a histone deacetylase inhibitor, MS-275, could suppress tumor growth in a RARβ2-negative human cutaneous T cell lymphoma (CTCL) cell lines and freshly isolated primary CTCL cells, and to elucidate the epigenetic mechanism behind the phenomena. Methods: SeAx cells were implanted subcutaneously in NOD-SCID mice which were randomly divided into four groups and treated with either Am80, MS-275 by oral gavage (five days/week), or a combination of the two agents. Cell proliferation assay, methylation-specific PCR, flow cytometric analysis of cell cycle and apoptosis and chromatin immunoprecipitation assay were employed. Results: Quantitative PCR analysis revealed that RARβ2 gene expression was restored only by this combination rather than by either of the agents singly. Restored retinoid sensitivity was observed in combining retinoid with a histone deacetylase inhibitor significantly inhibited cell growth in vitro, suppressed subcutaneously transplanted tumor growth, and prolonged survival of tumor-bearing mice in vivo by more strongly inducing apoptosis and p21 expression in CTCL cells than either agent alone. In the combination treatment, the histone H4 acetylation level at lysine 12 and 16 in the promoter region increased after restoration of RARβ2 expression although the DNA methylation of RARβ2 remained unchanged. Conclusion: This is the first report of histone acetylation as the primary event in the restoration of RARβ2. Inducible RARβ2 expression may serve as a reliable predictor for tumor response in patients undergoing 'epigenetic & differentiation' therapy.
    Article · Oct 2015 · Journal of dermatological science