Published papers

The Shumiya cataract rat (SCR) is a hereditary cataract model in which lens opacity appears spontaneously in both the nuclear and perinuclear regions of 10-11 week old animals. The expression of drug metabolizing enzymes, including cytochrome P450 (CYP) and conjugation enzymes, was investigated in the ocular tissues of SCRs during cataractogenesis. Significantly high levels of gene expression were detected for CYP1A1, CYP2B2, CYP2C11 and CYP2E1 in normal lenses, whereas CYP1A1 and CYP2C11 were at lower levels in the cataractous lenses. The gene expression profiles of conjugation enzymes were also compared between normal and cataractous ocular tissues in which a moderate reduction in ST1A1 and ST1B1 expression, and an extensive loss of UGT1A1 expression, were observed in the SCR animals that had developed cataracts. In contrast, the elevated expression of the GSTA family of genes was evident in cataractous lenses. The reduced expression of several drug metabolizing enzymes in the cataractous ocular tissues might therefore be related to cataractogenesis via the accumulation of endogenous or exogenous toxic substances.

We have previously reported the expression of CYP genes in human myeloblastic and lymphoid cell lines, and the induction of the CYP3A4 and GSTP1 genes by oxidative stress in the human erythroleukemia cell line, K562. To further elucidate the role of drug metabolizing enzymes in hematogenesis, we have characterized the expression of CYP genes in hemin-induced differentiated K562 cells. After incubation with 50 μM hemin for 3 d, the expression of CYP1A1 and CYP3A4 genes was induced by 2.5- and 3.5-fold, respectively. In contrast, the CYP1B1 and CYP2E1 genes were downregulated in these cells to below 10% of the control levels. Moreover, these changes correlated with the hemin dose and culture time. Metabolism of midazolam, a probe substrate for CYP3A4, in the differentiated K562 cells increased by 2-folds, suggesting that the induction of CYP3A4 activity is consistent with the mRNA level. If these changes in the CYP expression profile in hematopoietic cells occurred, the susceptibility to xenobiotics and/or the therapeutic drugs of the cells might be influenced, and it also affects the metabolism of endogenous substrates, such as steroids and prostaglandins. © 2007 Pharmaceutical Society of Japan.

A single injection of an overdose of selenite is known to induce cataracts in young rat eyes. In our current study, we have investigated the gene expression profiles of the cytochrome P450s (CYPs) in the ocular tissues of rats developing such selenite-induced cataracts. Seven days after the injection of selenite, the expression levels of the CYP1A1 and CYP2E1 genes in the lenses of these animals increased and a slight reduction in the expression of the CYP3A gene family could be observed in the extralenticular tissues. When pantethine, an antioxidant, was administered 30 min before selenite injection, the extent of the CYP gene expression changes diminished. These results suggest that selenite-induced oxidative stress may play a role in both the induction and downregulation of CYP genes. In addition, the elevated expression of CYP1A1 and CYP2E1 in the lens may underlie the enhancement of cataract development induced by selenite.

We identified a cDNA encoding a putative cytosolic sulfotransferase (SULT) by searching the expressed sequence tag database of Bombyx mori, and subsequently obtained the full-length cDNA for this gene via rapid amplification of cDNA ends (RACE). We designated this gene bmST1, and showed by sequence analysis that it belongs to a novel SULT family. The tissue specificity of bmST1 mRNA expression was examined in fifth instar larvae by reverse transcriptase-polymerase chain reaction (RT-PCR), and transcripts were detectable in the silk gland, gut, fat body, and Malpighian tube. A recombinant form of bmST1 was then expressed using a gluthathione S-transferase (GST) gene fusion system, and it was purified from Escherichia coli. Purified bmST1 did not exhibit sulfating activity toward SULT substrates such as 4-nitrophenol, vanillin, hydroxysteroids, or monoamines. Surprisingly, however, recombinant bmST1 showed considerable activity toward 4-nitrocatechol and also gallate esters, although the catechins are not sulfated by this enzyme.

We have isolated a gene (clone Y113G7A.11) from Caenorhabditis elegans (C. elegans), that we have designated as ceST1, and which is the only member of the cytosolic sulfotransferase (SULT) gene family present in the genome of this organism. We identified the SULT motifs of ceST1 based upon their deduced amino acid sequence, and subsequently expressed the ceST1 cDNA in Escherichia coli and characterized its enzymatic properties. The recombinant protein showed sulfation activity for 4-nitrophenol and 2-naphthol substrates, but did not catalyze the sulfation of either monoamines or hydroxysteroids. Another compound sulfated by ceST1 is bisphenol A, which is known to stimulate germ cell proliferation in C. elegans. SULT activity was not detected in the cytosol of C. elegans, probably due to heat labile inhibitors. The ceST1 protein was detectable in the cytosol of C. elegans using anti-sera raised against recombinant ceST1, and transcripts could also be detected throughout the developmental stages. Moreover, high levels of ceST1 expression were evident at both the embryonic and adult stages and were augmented in dauer larva. These findings suggest that this sulfotransferase either forms part of a defence system against xenobiotics or regulates germ cell proliferation in C. elegans. © 2006 The Japanese Biochemical Society.

To prevent lens opacification and cataract formation, the lens contains α-crystallin, which has been shown to function as a molecular chaperone that maintains the correct folding of other proteins. Oxidative stress is known to be an important factor in the initiation and progression of a cataract. So far, several antioxidant compounds have been reported to prevent cataracts in vivo and in vitro. This stress also triggers α-crystallin modifications and alters its chaperone activity. However, few studies have examined the relationship between the consumption of antioxidant compounds and lens chaperone activity. To elucidate the effect of antioxidants on lens chaperone activity, antioxidants were administered to a selenite-induced cataract model of rats. The chaperone activity in lens water-soluble fraction was measured using aldehyde dehydrogenase. All antioxidant treatment groups, except decaffeinated coffee treatment, had less severe central opacities and lower stage cataracts than control groups. The chaperone activity was weaker in lens of selenite cataract rats, but antioxidant compounds and coffee treatment can prevent the chaperone activity decreasing, but not decaffeinated coffee. These results suggested that the treatment with antioxidant compounds could prevent cataract formation by the maintenance of the chaperone activity in water-soluble lens proteins. Thus, this study describes the development of an anticataract drug target for lens chaperone activity.

Anaplastic large cell lymphomas (ALCL) are mainly characterized by harboring the fusion protein nucleophosmin-anaplastic lymphoma kinase (NPM-ALK). The ALK inhibitor, crizotinib specifically induced apoptosis in Ba/F3 cells expressing NPM-ALK by inhibiting the activation of NPM-ALK and its downstream molecule, signal transducer and activator of transcription factor 3 (STAT3). We found that α-tocopherol, a major component of vitamin E, attenuated the effects of crizotinib independently of its anti-oxidant properties. Although α-tocopherol suppressed the inhibitory effects of crizotinib on the signaling axis including NPM-ALK and STAT3, it had no influence on the intake of crizotinib into cells. Crizotinib also directly inhibited the kinase activity of NPM-ALK; however, this inhibitory effect was not altered by the co-treatment with α-tocopherol. Whereas the nuclear localization of NPM-ALK was disappeared by the treatment with crizotinib, the co-treatment with α-tocopherol swept the effect of crizotinib and caused the localization of NPM-ALK in nucleus. The administration of α-tocopherol attenuated the anti-tumor activity of crizotinib against NPM-ALK-provoked tumorigenesis in vivo. Furthermore, the α-tocopherol-induced inhibition of crizotinib-caused apoptosis was also observed in NPM-ALK-positive cells derived from ALCL patients, namely, SUDHL-1 and Ki-JK. Collectively, these results not only revealed the novel mechanism underlying crizotinib-induced apoptosis in NPM-ALK-positive cells, but also suggest that the anti-tumor effects of crizotinib are attenuated when it is taken in combination with vitamin E.

© 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.

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.

Previously we have reported our analyses of cytochrome P450 (CYP) expression in rat ocular tissues and in our current study we have extended these analyses to the different stages of growth in both male and female rats. Additionally, we have examined the expression levels of the different conjugation enzymes, sulfotransferases (SULTs), UDP-glucuronosyl transferases (UGTs) and glutathione S-transferases (GSTs), in ocular tissues. In 5-week-old animals, the CYP genes, CYP2B2 and CYP3A1, were abundantly expressed in the lens, with higher CYP1A1 expression detectable in the extra-lenticular tissues, of both genders. However, the expression of CYP1A2 and CYP2E1 in female ocular tissues was more extensive than in male. Moreover, in females the expression of the phenol-sulfating SULTs, ST1A1, ST1B1 and ST1C1, was more abundant in the extra-lenticular tissues, whereas the levels of the hydroxysteroid-sulfating SULTs, ST2A1 and ST2A5, predominated in the lens. The expression levels of the UGTs, UGT1A1, UGT1A6 and UGT2B1, were also higher in the female extra-lenticular tissues but the expression of the GSTA subfamily (GSTA1 and GSTA2) was very weak in the ocular tissues of both genders. The overall gene expression profiles were found to change with the age of the animals (from 3 to 8 weeks) and, in general, the expression levels of the CYPs and SULTs declined with age, whereas the levels of the UGTs and GSTs increased. These results demonstrate that the expression profiles of drug metabolising enzymes show both region- and gender-specific patterns in rat ocular tissues. © 2005 Elsevier Ltd. All rights reserved.

Formaldehyde (FA), acetaldehyde (AA) and oligomers in recycled polyethylene terephthalate (PET) were analyzed by HPLC. All of the physically recycled PET contained detectable levels of FA, AA and oligomers, and the levels were almost the same as in used bottles. Most superclean-like and chemically recycled PET contained lower levels than new pellets. These compounds showed no decrease upon physical recycling, but showed a marked decrease upon superclean-like recycling. In PET sheets made using physically recycled PET, FA was decreased, though AA was increased by the sheeting process as same as new one. FA, AA and oligomers originated from PET resin and their levels in recycled products were almost equivalent to those in new products. It was concluded that there is no particular safety concern about their presence in recycled PET.

The residual volatiles in recycled polyethylene terephthalate (PET) were analyzed using headspace/GC/MS. Recycled PET samples were made from PET bottles used for beverages, alcohol and soy sauce, and they were recycled in physical recycling plants, chemical recycling plants and superclean-like recycling trials. The physically recycled PET flakes contained small amounts of volatiles such as ethanol, limonene, 2-methyl-1,3-dioxolane, acetone, octanal and nonanal. Most of them originated from foods packed in bottles, and only 2-methyl-1,3-dioxolane was derived from polymer impurities. In contrast, the superclean-like or chemically recycled PET contained no detectable volatiles, like new PET pellets. The PET sheets shaped from physically recycled PET had no detectable volatiles. Not only the chemically and superclean-like recycled PET, but also the physically recycled PET contained no hazardous volatiles. It was concluded that there is no safety concern about volatiles in recycled PET, for the present use.

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.

This paper describes sensitive and reliable determination of midazolam (MDZ) and its major metabolite 1′-hydroxymidazolam (1-OHMDZ) in human plasma by liquid chromatography-mass spectrometry (LC-MS) with a sonic spray ionization (SSI) interface. MDZ, 1-OHMDZ and diazepam as an internal standard were extracted from 1 ml of alkalinized plasma using n-hexane-chloroform (70:30, v/v). The extract was injected into an analytical column (YMC-Pak Pro C18, 50 mm × 2.0 mm i.d.). The mobile phase for separation consisted of 10 mM ammonium acetate and methanol (50:50, 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 total time for chromatographic separation was less than 16 min. The validated concentration ranges of this method were 0.25-50 ng/ml for both MDZ and 1-OHMDZ. Mean recoveries were 93.6% for MDZ and 86.6% for 1-OHMDZ. Intra- and inter-day coefficient variations were less than 6.5 and 5.5% for MDZ, and 6.1 and 5.7% for 1-OHMDZ at 0.3, 4, 20 and 40 ng/ml. The limits of quantification were 0.25 ng/ml for both MDZ and 1-OHMDZ. This method was sensitive and reliable enough for pharmacokinetic studies on healthy volunteers, and was applied for the measurement of CYP3A activity in humans after an intravenous (1 mg) and a single-oral administration (2 mg) of subtherapeutic MDZ dose. © 2006 Elsevier B.V. All rights reserved.