Details of a Researcher - Tamura, Hiroomi

Papers - Tamura, Hiroomi

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Phosphorylated CIS suppresses the Epo or JAK2 V617F mutant-triggered cell proliferation through binding to EpoR.

TAMURA Hiroomi

Cellular Signaling (Cellular Signalling) 31 41 - 57 2016.12

Research paper (scientific journal), Joint Work, Accepted, ISSN 0898-6568

© 2016 Elsevier Inc. The JAK2 V617F mutant-mediated aberrant signaling pathway is a hallmark of myeloproliferative neoplasms (MPNs). Although cytokine-inducible Src homology 2 protein (CIS) and suppressors of cytokine signaling (SOCS) are negative regulators of the JAK-STAT pathway, the functional role of CIS/SOCS family members in the JAK2 V617F mutant-induced oncogenic signaling pathway has not yet been elucidated. In this study, we found that the expression of CIS and SOCS1 was induced through the activation of signal transducer and activator of transcription 5 (STAT5) in not only the cells stimulated with Epo or IL-3 but also the cells transformed by the JAK2 V617F mutant. Cell proliferation and tumor formation in nude mice induced by the JAK2 V617F mutant were significantly enhanced when the expression of CIS was silenced using an RNA interference technique, whereas the knockdown of SOCS1 had no effect. The enforced expression of CIS caused apoptotic cell death in the transformed by JAK2 V617F mutant and drastically inhibited the JAK2 V617F mutant-induced tumor formation. CIS interacted with phosphorylated EpoR at Y401, which was critical for the activation of STAT5 and ERK. Whereas the activation of STAT5 and ERK in the transformed cells by JAK2 V617F mutant was increased by the knockdown of CIS, the enforced expression of CIS reduced the activation of these molecules. Furthermore, these anti-tumor effects of CIS required the function of SH2 domain and its tyrosine phosphorylation at Y253. We herein elucidated the mechanism by which CIS functions as a novel type of tumor suppressor in JAK2 V617F mutant-induced tumorigenesis.

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Three tyrosine residues in the erythropoietin receptor are essential for Janus kinase 2 V617F mutant-induced tumorignesis.

TAMURA Hiroomi

J. Biol. Chem. (Journal of Biological Chemistry) 292 ( 5 ) 1826 - 1846 2016.12

Research paper (scientific journal), Joint Work, Accepted, ISSN 0021-9258

© 2017 by The American Society for Biochemistry and Molecular Biology, Inc. The erythropoietin receptor (EpoR) regulates development of blood cells, and its full activation normally requires the cytokine erythropoietin (Epo). In the case of myeloproliferative neoplasms (MPN), Epo-independent signaling through EpoR can be caused by a point mutation, V617F, in the EpoR-interacting tyrosine kinase Janus kinase 2 (JAK2). In cells expressing the JAK2 V617F mutant, eight tyrosine residues in the intracellular domain of EpoR are phosphorylated, but the functional role of these phosphorylations in oncogenic signaling is incompletely understood. Here, to evaluate the functional consequences of the phosphorylation of these tyrosine residues, we constructed an EpoR-8YF mutant in which we substituted all eight tyrosine residues with phenylalanine. Co-expression of EpoR-8YF with the JAK2 V617F mutant failed to induce cytokine-independent cell proliferation and tumorigenesis, indicating that JAK2-mediated EpoR phosphorylation is the reason for JAK2 V617F mutant-induced oncogenic signaling. An exhaustive mutational analysis of the eight EpoR tyrosine residues indicated that three of these residues, Tyr-343, Tyr-460, and Tyr-464, are required for the JAK2 V617F mutant to exhibit its oncogenic activity.We also showed that phosphorylation at these three residues was necessary for full activation of the transcription factor STAT5, which is a critical downstream factor of JAK2 V617F-induced oncogenic signaling. In contrast, Epo stimulation could moderately stimulate the proliferation of cells expressing wild type JAK2 and EpoR-8YF, suggesting that the requirement of the phosphorylation of these three tyrosine residues seems to be specific for the oncogenic proliferation provoked by V617F mutation. Collectively, these results have revealed that phosphorylation of Tyr-343, Tyr-460, and Tyr-464 in EpoR underlies JAK2 V617F mutant-induced tumorigenesis. We propose that the targeted disruption of this pathway has therapeutic utility for managing MPN.

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Roasted coffee induces aldo-keto reductase 1C3 (AKR1C3) expression in human prostate cancer LNCaP cells associated with Nrf2 activation.

TAMURA Hiroomi

Oncology letters 1 - 6 2016.11

Research paper (scientific journal), Joint Work, Accepted

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Inhibitory effects of flavonoids extracted from Nepalese propolis on the LPS signaling pathway.

TAMURA Hiroomi

Int. Immunopharmacol. (International Immunopharmacology) 40 550 - 560 2016.10

Research paper (scientific journal), Joint Work, Accepted, ISSN 1567-5769

© 2016 Elsevier B.V. Flavonoids, particularly those derived from plants, harbor biological effects such as anti-inflammation and the inhibition of cancer progression. In the present study, we investigated the effects of 10 kinds of flavonoids isolated from Nepalese propolis on the LPS signaling pathway in order to clarify their anti-inflammatory activities. Five types of flavonoids: isoliquiritigenin, chrysin, 3′,4′-dihydroxy-4-methoxydalbergione, 4-methoxydalbergion, and cearoin, markedly inhibited inflammatory responses including LPS-induced NO production by suppressing the expression of iNOS mRNA and LPS-induced mRNA expression of TNFα and CCL2. Their inhibitory effects on LPS-induced inflammatory responses correlated with the intensities of these flavonoids to suppress the LPS-induced activation of nuclear factor κB (NF-κB), an essential transcription factor for the mRNA expression of iNOS, TNFα, and CCL2. Among these flavonoids, 3′,4′-dihydroxy-4-methoxydalbergione and 4-methoxydalbergion markedly inhibited the LPS-induced activation of IKK, thereby abrogating the degradation of IκBα and nuclear localization of NF-κB. On the other hand, isoliquiritigenin, chrysin, and cearoin failed to inhibit these signaling steps, but suppressed the transcriptional activity of NF-κB, which caused their anti-inflammatory effects. The results of the present study revealed that these five kinds of flavonoids are the components of Nepalese propolis that exhibit anti-inflammatory activities with a different regulatory mechanism for the activation of NF-κB.

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The extracellular C-loop domain plays an important role in the cell adhesion function of aquaporin 0.

TAMURA Hiroomi

Current Eye Research (Current Eye Research) 42 ( 4 ) 617 - 624 2016.10

Research paper (scientific journal), Joint Work, Accepted, ISSN 0271-3683

© 2016 Taylor & Francis. Purpose: Although aquaporin 0 (AQP0) is a member of the AQP family, it has limited water permeability compared with other members. AQP0 may also have cell adhesion-related functions, but the evidence is still limited. Here, we studied the relationship of AQP0 to cell adhesion and determined the region required for cell adhesion.Methods: L-cell fibroblasts stably expressing AQP0 or AQP1 (L-AQP0 or L-AQP1) were established. One group of cells was stained with CellTracker Red and cultured into a confluent monolayer, whereas the other group was loaded with CellTracker Blue and seeded over the monolayer. To study cell adhesion, the percentages of lower and upper layer cells were measured using flow cytometry. To determine the region of AQP0 required for adhesion, activity was done by pull-down assay using glutathione S-transferase fusion proteins. To study the water permeability, Xenopus laevis oocyte expressing AQP0 wild-type or AQP0 mutated in C-loop was transferred to a hypotonic solution and photographed, and the diameter was measured to calculate the volume.Results: More cells adhered to the lower cells in the L-AQP0 homotypic pair than other pairs such as L-AQP1 homotypic or L-AQP0/L-AQP1 heterotypic pairs. Pull-down assays revealed that AQP0 could bind to itself via the C-loop extracellular domain. Furthermore, we determined that 109Pro and 110Pro in the C-loop were important for cell adhesion. However, mutation of the C-loop in AQP0 did not affect its water permeability.Conclusions: AQP0 is known to bind lipids in the opposing membrane. Our data suggest that this cell-to-cell adhesion occurs not only in the AQP0/liquids but also via AQP0/AQP0 interaction through the C-loop domain. Mutations in the C-loop amino acids did not affect the water permeability of AQP0 but did affect its cell adhesion function. These independent dual functions of AQP0 are important for lens transparency.

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A bis-malonic acid fullerene derivative significantly suppressed IL-33-induced IL-6 expression by inhibiting NF-κB activation.

TAMURA Hiroomi

Int Immunopharmacol. (International Immunopharmacology) 40 254 - 264 2016.09

Research paper (scientific journal), Joint Work, Accepted, ISSN 1567-5769

IL-33 functions as a ligand for ST2L, which is mainly expressed in immune cells, including mast cells. IL-33 is a potent inducer of pro-inflammatory cytokines, such as IL-6, and has been implicated in the pathogenesis of allergic inflammatory diseases. Therefore, IL-33 has recently been attracting attention as a new target for the treatment of inflammatory diseases. In the present study, we demonstrated that a water-soluble bis-malonic acid fullerene derivative (C60-dicyclopropane-1,1,1',1'-tetracarboxylic acid) markedly diminished the IL-33-induced expression of IL-6 in bone marrow-derived mast cells (BMMC). The bis-malonic acid fullerene derivative suppressed the canonical signaling steps required for NF-κB activation such as the degradation of IκBα and nuclear translocation of NF-κB by directly inhibiting the IL-33-induced IKK activation. Although p38 and JNK also contributed to IL-33-induced expression of IL-6, the bis-malonic acid fullerene derivative did not affect their activation. Furthermore, the bis-malonic acid fullerene derivative had no effect on the NF-κB activation pathway induced by TNFα and IL-1. These results suggest that the bis-malonic fullerene derivative has potential as a specific drug for the treatment of IL-33-induced inflammatory diseases by specifically inhibiting the NF-κB activation pathway.

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Effect of hesperetin on chaperone activity in selenite-induced cataract.

TAMURA Hiroomi

Open Medicine (Open Medicine (Poland)) 11 ( 1 ) 183 - 189 2016.06

Research paper (scientific journal), Joint Work, Accepted

© Yosuke Nakazawa et al published by De Gruyter Open 2016. Background. Chaperone activity of α-crystallin in the lens works to prevent protein aggregation and is important to maintain the lens transparency. This study evaluated the effect of hesperetin on lens chaperone activity in selenite-induced cataracts. Methodology. Thirteen-day-old rats were divided into four groups. Animals were given hesperetin (groups G2 and G4) or vehicle (G1 and G3) on Days 0, 1, and 2. Rats in G3 and G4 were administered selenite subcutaneously 4 hours after the first hesperetin injection. On Days 2, 4, and 6, cataract grades were evaluated using slit-lamp biomicroscopy. The amount of a-crystallin and chaperone activity in water-soluble fraction were measured after animals sacrificed. Results. G3 on day 4 had developed significant cataract, as an average cataract grading of 4.6 ± 0.2. In contrast, G4 had less severe central opacities and lower stage cataracts than G3, as an average cataract grading of 2.4 ± 0.4. The a-crystallin levels in G3 lenses were lower than in G1, but the same as G4. Additionally, chaperone activity was weaker in G3 lenses than G1, but the same as in G4. Conclusions. Our results suggest that hesperetin can prevent the decreasing lens chaperone activity and a-crystallin water solubility by administered of selenite.

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Data supporting mitochondrial morphological changes by SPG13-associated HSPD1 mutants.

TAMURA Hiroomi

Data in Brief 6 482 - 488 2016.03

Research paper (scientific journal), Joint Work, Accepted

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Coffee induces vascular endothelial growth factor (VEGF) expression in human neuroblastama SH-SY5Y cells.

TAMURA Hiroomi

Nutritional Neuroscience (Nutritional Neuroscience) 20 ( 6 ) 336 - 342 2016.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 1028-415X

© 2016 Taylor & Francis. Recent evidence indicates that hypoxia-inducible vascular endothelial growth factor (VEGF) has neurotrophic and neuroprotective effects on neuronal and glial cells. On the other hand, recent epidemiological studies showed that daily coffee consumption has been associated with a lower risk of several neuronal disorders. Therefore, we investigated the effect of coffee on VEGF expression in human neuroblastoma SH-SY5Y cells. We found that even low concentration of coffee (<2%) strongly induced VEGF expression via an activation of HIF-1α. The activation of HIF-1α by coffee was attributed to the coffee-dependent inhibition of prolyl hydroxylation of HIF1α, which is essential for proteolytic degradation of HIF-1α. However, no inhibition was observed at the catalytic activity in vitro. Coffee component(s) responsible for the activation of HIF-1α was not major constituents such as caffeine, caffeic acid, chlorogenic acid, and trigonelline, but was found to emerge during roasting process. The active component(s) was extractable with ethyl acetate. Our results suggest that daily consumption of coffee may induce VEGF expression in neuronal cells. This might be related to protective effect of coffee on neural disorders such as Alzheimer's disease and Parkinson's disease.

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アクアポリン0(AQP0)の細胞間接着に関与するアミン酸の特定

TAMURA Hiroomi

日本眼科学会誌 120 ( 1 ) 50 2016.01

Research paper (scientific journal), Joint Work

A proline type fullerene derivative inhibits adipogenesis by preventing PPARgamma activation.

TAMURA Hiroomi

Biochemistry and Biophysics Reports (Biochemistry and Biophysics Reports) 5 259 - 265 2016.01

Research paper (scientific journal), Joint Work, Accepted

© 2016 The Authors. Obesity and its associated metabolic diseases represent some of the most rapidly expanding health issues worldwide, and, thus, the development of a novel chemical compound to suppress adipogenesis is strongly expected. We herein investigated the effects of water-soluble fullerene derivatives: a bis-malonic acid derivative and three types of proline-type fullerene derivatives, on adipogenesis using NIH-3T3 cells overexpressing PPARγ. One of the proline-type fullerene derivatives (P3) harboring three carboxy groups significantly inhibited lipid accumulation and the expression of adipocyte-specific genes, such as aP2, induced by the PPARγ agonist rosiglitazone. On the other hand, the bis-malonic acid derivative (M) and the 2 other proline-type fullerene derivatives (P1, P2), which have two carboxy groups, had no effect on PPARγ-mediated lipid accumulation or the expression of aP2. P3 fullerene also inhibited lipid accumulation induced by the combined stimulation with 3-isobutyl-1-methylxanthine (IBMX), dexamethasone, and insulin in 3T3-L1 preadipocytes. During the differentiation of 3T3-L1 cells into adipocytes, P3 fullerene did not affect the expression of C/EBPδ, C/EBPβ, or PPARγ, but markedly inhibited that of aP2 mRNA. These results suggest that P3 fullerene exhibits anti-obesity activity by preventing the activation of PPARγ.

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Coffee Modulates the Function of Brain-Derived Neurotrophic Factor (BDNF) in Human Neuroblastoma SH-SY5Y Cells.

TAMURA Hiroomi

Neuroscience & Medicine 6 165 - 174 2015.12

Research paper (scientific journal), Single Work, Accepted

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Meta-analysis: Effects of probiotic supplementation on lipid profiles in normal to mildly hypercholesterolemic individuals.

TAMURA Hiroomi

PLoS One (PLoS ONE) 10 ( 10 ) e0139795 2015.10

Research paper (scientific journal), Joint Work

© 2015 Shimizu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Introduction Recent experimental and clinical studies have suggested that probiotic supplementation has beneficial effects on serum lipid profiles. However, there are conflicting results on the efficacy of probiotic preparations in reducing serum cholesterol. Objective To evaluate the effects of probiotics on human serum lipid levels, we conducted a metaanalysis of interventional studies. Methods Eligible reports were obtained by searches of electronic databases. We included randomized, controlled clinical trials comparing probiotic supplementation with placebo or no treatment (control). Statistical analysis was performed with Review Manager 5.3.3. Subanalyses were also performed. Results Eleven of 33 randomized clinical trials retrieved were eligible for inclusion in the meta-Analysis. No participant had received any cholesterol-lowering agent. Probiotic interventions (including fermented milk products and probiotics) produced changes in total cholesterol (TC) (mean difference-0.17 mmol/L, 95% CI:-0.27 to-0.07 mmol/L) and low-density lipoprotein cholesterol (LDL-C) (mean difference-0.22 mmol/L, 95% CI:-0.30 to-0.13 mmol/ L). High-density lipoprotein cholesterol and triglyceride levels did not differ significantly between probiotic and control groups. In subanalysis, long-Term (>4-week) probiotic intervention was statistically more effective in decreasing TC and LDL-C than short-Term (4-week) intervention. The decreases in TC and LDL-C levels with probiotic intervention were greater in mildly hypercholesterolemic than in normocholesterolemic individuals. Both fermented milk product and probiotic preparations decreased TC and LDL-C levels. Gaio and the Lactobacillus acidophilus strain reduced TC and LDL-C levels to a greater extent than other bacterial strains. Conclusions In conclusion, this meta-Analysis showed that probiotic supplementation could be useful in the primary prevention of hypercholesterolemia and may lead to reductions in risk factors for cardiovascular disease.

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Nepetaefuran and leonotinin isolated from Leonotis nepetaefolia R. Br. potently inhibit the LPS signaling pathway by suppressing the transactivation of NF-κB.

TAMURA Hiroomi

Int Immunopharmacol (International Immunopharmacology) 28 ( 2 ) 967 - 976 2015.10

Research paper (scientific journal), Joint Work, Accepted, ISSN 1567-5769

© 2015 Elsevier B.V. Leonotis nepetaefolia R. Br., also known as Klip Dagga or Lion's Ear, has traditionally been used as a folk medicine to treat inflammatory diseases such as rheumatism, bronchitis, and asthma; however, the components that exhibit its anti-inflammatory activity have not yet been identified. In the present study, we investigated the effects of three types of diterpenoids, nepetaefuran, leonotinin, and leonotin, which were isolated from L. nepetaefolia R. Br., on the LPS signaling pathway in order to elucidate the anti-inflammatory mechanism involved. Nepetaefuran more potently inhibited the LPS-induced production of NO and CCL2 than leonotinin by suppressing the expression of iNOS mRNA and CCL2 mRNA. On the other hand, leonotin failed to inhibit the production of NO and CCL2 induced by LPS. Although nepetaefuran and leonotinin had no effect on the LPS-induced degradation of IκBα or nuclear translocation of NF-κB p65, they markedly inhibited the transcriptional activity of NF-κB. Nepetaefuran and leonotinin also inhibited the transcriptional activity of the GAL4-NF-κB p65 fusion protein. On the other hand, nepetaefuran, leonotinin and leonotin did not affect the LPS-induced activation of MAP kinase family members such as ERK, p38, and JNK. In addition, inhibitory effect of nepetaefuran and leonotinin on NF-κB activation is well correlated with their ability to induce activation of Nrf2 and ER stress. Taken together, these results demonstrated that nepetaefuran and leonotinin could be the components responsible for the anti-inflammatory activity of L. nepetaefolia R. Br. by specifically inhibiting the LPS-induced activation of NF-κB.

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Hypomyelinating leukodystrophy-associated missense mutation in HSPD1 blunts mitochondrial dynamics

Miyamoto Yuki, Eguchi Takahiro, Kawahara Kazuko, Hasegawa Nanami, Nakamura Kazuaki, Funakoshi-Tago Megumi, Tanoue Akito, Tamura Hiroomi, Yamauchi Junji

Biochemical and Biophysical Research Communications (Biochemical and Biophysical Research Communications) 462 ( 3 ) 275 - 281 2015.06

Research paper (scientific journal), Joint Work, Accepted, ISSN 0006-291X

Myelin-forming glial cells undergo dynamic morphological changes in order to produce mature myelin sheaths with multiple layers. In the central nervous system (CNS), oligodendrocytes differentiate to insulate neuronal axons with myelin sheaths. Myelin sheaths play a key role in homeostasis of the nervous system, but their related disorders lead not only to dismyelination and repeated demyelination but also to severe neuropathies. Hereditary hypomyelinating leukodystrophies (HLDs) are a group of such diseases affecting oligodendrocytes and are often caused by missense mutations of the respective responsible genes. Despite increasing identification of gene mutations through advanced nucleotide sequencing technology, studies on the relationships between gene mutations and their effects on cellular and subcellular aberrance have not followed at the same rapid pace. In this study, we report that an HLD4-associated (Asp-29-to-Gly) mutant of mitochondrial heat shock 60-kDa protein 1 (HSPD1) causes short-length morphologies and increases the numbers of mitochondria due to their aberrant fission and fusion cycles. In experiments using a fluorescent dye probe, this mutation decreases the mitochondrial membrane potential. Also, mitochondria accumulate in perinuclear regions. HLD4-associated HSPD1 mutant blunts mitochondrial dynamics, probably resulting in oligodendrocyte malfunction. This study constitutes a first finding concerning the relationship between disease-associated HSPD1 mutation and mitochondrial dynamics, which may be similar to the relationship between another disease-associated HSPD1 mutation (MitCHAP-60 disease) and aberrant mitochondrial dynamics.

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Quantitation of pilsicainide in microscale samples of human biological fluids using liquid chromatography-tandem mass spectrometry

Shimizu Mikiko, Hashiguchi Masayuki, Shiga Tsuyoshi, Nakamura Koichi, Tamura Hiro omi, Mochizuki Mayumi

Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences (Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences) 985 172 - 179 2015.03

Research paper (scientific journal), Joint Work, Accepted, ISSN 1570-0232

This paper describes a sensitive, reliable method to determine pilsicainide (PLC) levels in microscale sample volumes of human biological fluids using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). PLC and quinidine as an internal standard were extracted with diethylether from 0.1. mL of alkalinized biological fluids. The extract was injected into an analytical column (l-column 2 ODS, 75. mm. ×. 2.1. mm i.d.). The mobile phase for separation consisted of 5. mM ammonium acetate (pH 4.5)/methanol (4:1, v/v) and was delivered at a flow rate of 0.2. mL/min. The drift voltage was 100. V. The sampling aperture was heated at 120. °C and the shield temperature was 260. °C. The ion transitions used to monitor analytes were m/. z 273. →. m/. z 110 for PLC and m/. z 325. →. m/. z 79 for quinidine. The total time for chromatographic separation was less than 8. min. The validated concentration ranges of this method for PLC were 5-2000. ng/mL in plasma, 5-500. ng/mL in ultrafiltered plasma solution, and 25-2000. ng/mL in urine. Mean recoveries of PLC in plasma, ultrafiltered plasma solution, and urine were 93.2-99.7%, 91.4-100.6%, and 93.9-104.7%, respectively. Intra- and interday coefficients of variation for PLC were less than 6.0% and 4.3% in plasma, 6.1% and 3.7% in ultrafiltered plasma solution, and 5.4% and 2.5% in urine at the above concentration ranges, respectively. The lower limit of quantification for PLC in plasma, ultrafiltered plasma solution, and urine were 5. ng/mL, 5. ng/mL, and 25. ng/mL, respectively. This method can be applied to pharmacokinetic study and therapeutic drug monitoring in special populations such as neonates, infants, and the elderly by making effective use of residual samples used for general clinical laboratory testing.

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Anti-inflammatory activity of flavonoids in Nepalese propolis is attributed to inhibition of the IL-33 signaling pathway

Funakoshi-Tago Megumi, Okamoto Kazuhi, Izumi Rika, Tago Kenji, Yanagisawa Ken, Narukawa Yuji, Kiuchi Fumiyuki, Kasahara Tadashi, Tamura Hiroomi

International Immunopharmacology (International Immunopharmacology) 25 ( 1 ) 189 - 198 2015.03

Research paper (scientific journal), Joint Work, ISSN 1567-5769

Propolis has been used in folk medicine to improve health and prevent inflammatory diseases; however, the components that exhibit its anti-inflammatory activity remain unknown. We herein investigated the effects of flavonoids isolated from Nepalese propolis on the IL-33 signaling pathway to clarify the anti-inflammatory mechanism involved. Of the 8 types of flavonoids isolated from Nepalese propolis, 4 types of compounds, such as 3′,4′-dihydroxy-4-methoxydalbergione, 4-methoxydalbergion, cearoin, and chrysin, markedly inhibited the IL-33-induced mRNA expression of inflammatory genes including IL-6, TNFα and IL-13 in bone marrow-derived mast cells (BMMC). These four flavonoids also inhibited the IL-33-induced activation of nuclear factor κB (NF-κB), which was consistent with their inhibitory effects on cytokine expression. The effects of these flavonoids are attributed to inhibition of IL-33-induced activation of IKK, which leads to the degradation of IκBα and nuclear localization of NF-κB. On the other hand, other flavonoids isolated from Nepalese propolis, such as isoliquiritigenin, plathymenin, 7-hydroxyflavanone, and (+)-medicarpin, had no effect on the IL-33 signaling pathway or cytokine expression. Therefore, these results indicate that 3′,4′-dihydroxy-4-methoxydalbergione, 4-methoxydalbergion, cearoin, and chrysin are the substances responsible for the anti-inflammatory activity of Nepalese propolis.

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Effects of Coffee on Estrogen Sulfation in Human Colon Carcinoma Caco-2 Cells

Tamura H.

Coffee in Health and Disease Prevention (Coffee in Health and Disease Prevention) 545 - 552 2015

Research paper (scientific journal), ISSN 9780124095175

© 2015 Elsevier Inc. All rights reserved. Recent epidemiological studies have shown that moderate coffee consumption is associated with a lower risk of certain types of cancers, particularly colon cancer in postmenopausal women. To elucidate the molecular basis of the preventive action of coffee toward colon cancer, we focused on the effects of coffee on the metabolism of estrogens by sulfation, a reaction that inactivates estrogens. Estrogens are sulfonated by estrogen sulfotransferase (SULT1E1), and the sulfonated estrogens are reversely hydrolyzed by steroid sulfatase (STS). Sulfonated estrogens are pumped out of the cells by an ABC transporter, breast cancer resistance protein (BCRP). Intracellular concentrations of active estrogens may be determined by the balance of these activities. In human colon cancer Caco-2 cells, coffee decreases the expression of SULT1E1 and STS, whereas it increases BCRP expression. Activities of these three proteins change according to the expression level of each gene. Active constituents of coffee extract can be generated during the roasting process of coffee beans at different times. Modulation of the expression of these genes is likely to be mediated via activation of transcription factors such as NFκB (. BCRP) and stimulating protein 1 (. SULT1E1). These results suggest that coffee consumption may modulate the inactivation of estrogens by sulfation in human colon cells.

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Coffee inhibits adipocyte differentiation via inactivation of PPARgamma.

Ryohei Aoyagi, Megumi Funakoshi-Tago, Yosuke Fujiwara and Hiroomi Tamura*.

Biol. Pharm. Bull. 37 ( 11 ) 1820 - 1825 2014.11

Research paper (scientific journal), Joint Work, Accepted

Dexamemthasone suppresses neurosteroid biosynthesis via downregulation of steroidogenic enzyme gene expression in human glioma GI-1 cells.

Koibuchi F, Ritoh N, Aoyagi R, Funakoshi-Tago M, Tamura H*.

Bio Pharm Bull 37(7) 1241-1247 2014.07

Research paper (scientific journal), Joint Work, Accepted

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