M Miyake

Kobe Gakuin University, Kōbe-shi, Hyogo-ken, Japan

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Publications (27)46.56 Total impact

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    ABSTRACT: It has been reported that the activity of mitochondrial aconitase (m-aconitase) is rapidly inhibited in a variety of cells when exposed to nitric oxide (NO). In present study, we found that NO significantly increased the number of surviving neurons via enhanced mitochondrial functions with simultaneous addition of the [Fe(II)(β-citryl-L-glutamate; β-CG)] complex. In vitro, a variety of aconitase-inhibitors, such as fluorocitrate, cyanide ion, ferricyanide ([Fe(CN)6]), and various oxidants including superoxide anion, inhibited the activity of m-aconitase even in the presence of Fe(II), whereas a NO-donor, nitroprusside (SNP) ([Fe(CN)5NO]), was the only agent that significantly increased activity of that enzyme. Therefore, it is reasonable to assume that NO released from SNP promotes Fe-dependent activation of aconitase. All other tested NO-donors, including 3-morpholino-sydnonimine (SIN), Deta NONOate (NOC18), and NaNO2, also promoted activation of m-aconitase in time- and dose-dependent manners in the presence of Fe(II). The promoting effects of the NO-donors on activation disappeared with the addition of NO-scavengers. In intact mitochondria, all tested NO-donors promoted reactivation of aconitase in a dose-dependent manner in the presence of Fe(II), whereas that was not seen in its absence. These findings suggest that NO released from NO-donors promotes Fe-dependent activation of aconitase. In mixed neuronal and glial cultures, NO-donors except for SNP enhanced mitochondrial activity at low concentrations. Furthermore, simultaneous addition of the [Fe(II)(β-CG)] complex significantly enhanced those activities and greatly increased the number of surviving neurons. Thus, NO can carry Fe ions into m-aconitase via the guide of the tag of β-CG addressed to the enzyme.
    Biological & Pharmaceutical Bulletin 01/2013; 36(7):1068-79. · 1.85 Impact Factor
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    ABSTRACT: The compound β-citryl-L-glutamate (β-CG) was initially isolated from developing brains, though its functional roles remain unclear. In in vitro experiments, the [Fe(II)(β-CG)] complex activated aconitase in the presence of reducing reagents, whereas no Fe complex with citrate, glutamate, or deferoxamine displayed such an effect. β-CG and [Fe(II)(β-CG)] both bound to the fourth labile Fe atom (Fe(a)) in the [4Fe-4S] cluster of aconitase. Furthermore, [Fe(II)(β-CG)] reactivated aconitase damaged by ammonium peroxodisulfate (APS), while β-CG and citrate had no effect. These findings suggest that [Fe(II)(β-CG)] can transfer Fe to aconitase disassembled by APS. In intact mitochondria, both β-CG and [Fe(II)(β-CG)] bound to Fe(a) of aconitase, whereas only [Fe(II)(β-CG)] reactivated the enzyme disassembled by APS. In cultured neuronal cells, β-CG significantly enhanced cell viability by accelerating mitochondrial activity in primary cultures of neurons from newborn mouse cerebrum tissues. Thus, the β-CG plays a role as an Fe-carrier for mitochondrial aconitase, and then activates it. Taken together, these findings suggest that β-CG is an endogenous low molecular weight Fe chaperone for aconitase.
    Biological & Pharmaceutical Bulletin 01/2011; 34(9):1455-64. · 1.85 Impact Factor
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    ABSTRACT: β-Citryl-L-glutamate (β-CG) is a unique compound initially isolated from developing brains, which also appears in high concentrations during the period characterized by growth and differentiation of neurons in developing animals, and then decreases with maturation. However, its functional roles remain unclear. The stability constant obtained in our previous pH titration studies showed that β-CG forms relatively strong complexes with copper. Reactive oxygen species (ROS) and nitric oxide (NO) have been suggested to act as mediators of the cell death that occurs in neurons during development of the nervous system. However, regulation of ROS and NO formation by Cu in the developing brain remains poorly understood. The activity of superoxide dismutase (SOD), a key superoxide scavenging enzyme, is low in the developing brain. Furthermore, xanthine oxidase (XO) has been implicated in diverse pathological situations due to its capability of generating both ROS and NO. Therefore, we examined the effects of β-CG and its Cu-complex on SOD and XO activities. We found that the [Cu(II)(β-CG)] complex had SOD activity and a strong competitive inhibition of XO, while reduced glutathione caused concentration-dependent decreases of the XO inhibitory activities in the [Cu(II)(β-CG)] complex.
    Biological & Pharmaceutical Bulletin 01/2010; 33(12):1938-43. · 1.85 Impact Factor
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    ABSTRACT: The compound beta-citryl-L-glutamate (beta-CG) was initially isolated from developing brains, while it has also been found in high concentrations in testes and eyes. However, its functional roles are unclear. To evaluate its coordination with metal ions, we performed pH titration experiments. The stability constant, logbeta(pqr) for M(p)(beta-CG)(q)H(r) was calculated from pH titration data, which showed that beta-CG forms relatively strong complexes with Fe(III), Cu(II), Fe(II) and Zn(II). beta-CG was also found able to solubilize Fe more effectively from Fe(OH)(2) than from Fe(OH)(3). Therefore, we examined the effects of beta-CG on Fe-dependent reactive oxygen species (ROS)-generating systems, as well as the potential ROS-scavenging activities of beta-CG and metal ion-(beta-CG) complexes. beta-CG inhibited the Fe-dependent degradation of deoxyribose and Fe-dependent damage to DNA or plasmid DNA in a dose-dependent manner, whereas it had no effect on Cu-mediated DNA damage. In addition, thermodynamic data showed that beta-CG in a physiological pH solution is an Fe(II) chelator rather than an Fe(III) chelator. Taken together, these findings suggest that beta-CG is an endogenous low molecular weight Fe chelator.
    Biological & Pharmaceutical Bulletin 01/2010; 33(5):729-37. · 1.85 Impact Factor
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    ABSTRACT: Regulation of the kallikrein-kinin system in cerebral inflammation is still unclear. Here, we used reverse-transcription polymerase chain reaction (RT-PCR) techniques to show that lipopolysaccharide (LPS) activates the kallikrein-kinin system by enhancing liberation of bradykinin (BK), and alters mRNA levels of kallikrein-kinin system components, including high molecular weight (H-) and low molecular weight (L-) kininogens, in ECPC4 cells, a cell line of mouse choroid plexus epithelium. LPS treatment increased liberation of immunoreactive bradykinin in the supernatant of ECPC4 cells, and addition of LPS (500 ng/ml) to cultures resulted in elevation of H- and L-kininogen mRNA levels in ECPC4 cells within 24-48 h. Furthermore, LPS treatment elevated bradykinin type 2 and type 1 receptor mRNA levels within 4h, but did not change tissue kallikrein or plasma kallikrein mRNA levels. On the other hand, expression of pro-inflammatory mediators interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and cyclooxygenase-2 mRNA increased within 4-8h after addition of LPS to ECPC4 cells. The addition of IL-1beta and TNF-alpha to investigate the major mediator for kininogen expression in ECPC4 cells remarkably induced expression of H- and L-kininogen mRNAs in ECPC4 cells. These results suggest that LPS activates the kallikrein-kinin system in the choroid plexus via autocrine induction of IL-1beta and TNF-alpha.
    Neuroscience Letters 05/2008; 434(3):310-4. · 2.03 Impact Factor
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    ABSTRACT: Peroxisome proliferators (PxPs) induce peroxisomal beta-oxidation (Px-ox) in the liver of rodents and have a hypolipidemic function. To investigate hypolipidemic effect of PxPs, the relationship between TG fluctuation and Px-ox activity, as an indicator of the function of PxPs, was studied in primary cultured rat hepatocytes. Nafenopin (Nf) treatment of hepatocytes caused an increase in Px-ox activity in association with cellular TG accumulation in a time-dependent manner with a coefficient of r=0.918. This relationship between the activity and cellular TG were obtained using structurally diverse PxPs with a correlation coefficient of r=0.747. Treatment of the hypolipidemic drug, but non-PxP Pravastatin, decreased TG in the medium, but did not have the effects on cellular TG and Px-ox activity. The total amount of TG and diacylglycerol acyltransferase activity, the last enzyme in the TG de novo synthesis pathway, were not affected by Nf treatment. When hepatocytes were cultured with Brefeldin A, cellular TG was accumulated, the same as with Nf, however, Px-ox activity was not enhanced. Nf treatment markedly decreased the level of apolipoprotein B (apo B) in very low density lipoprotein (VLDL) fractions prepared from conditioned media and increased that of cellular apoB by Western blot analysis. Microsomal triglyceride transfer protein activity was not influenced by Nf. Together, with regards to TG lowering effect of PxPs, it is suggested that PxPs cause hepatocellular accumulation of TG without effects on TG biosynthesis and VLDL construction, and they might have inhibitory effect on VLDL secretion process.
    Biological & Pharmaceutical Bulletin 05/2007; 30(4):627-32. · 1.85 Impact Factor
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    ABSTRACT: The Sox6 gene is a member of the Sox gene family, which encodes transcription factors, and previous studies have suggested that it plays an important role in the development of the central nervous system. Aggregation of embryonic carcinoma P19 cells with retinoic acid (RA) results in the development of neurons, glia, and fibroblast-like cells. Sox6 mRNA increases rapidly in P19 cells during RA induction and then decreases during differentiation into neuronal cells. To investigate whether Sox6 expression is essential for neuronal differentiation, we established Sox6-suppressed P19 (P19[anti-Sox6]) cells by transfection of antisense-Sox6 cDNA. Most of the P19[anti-Sox6] cells showed no neurites and were not stained by the anti-MAP 2 antibody, while the suppression of Sox6 expression nearly totally blocked neuronal differentiation in P19 cells. Further, Sox6 suppression caused RA-dependent apoptosis by P19[anti-Sox6] cells: RA-treated P19[anti-Sox6] cells showed chromatin condensation, DNA fragmentation, and an increase in caspase-3-like activity. Thus, Sox6 is considered essential for neuronal differentiation and may play an important role in the early stages of neuronal differentiation or apoptosis.
    FEBS Letters 12/2004; 577(1-2):60-6. · 3.58 Impact Factor
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    ABSTRACT: The Sox6 gene is a member of the Sox gene family that encodes transcription factors. Previous studies have suggested that Sox6 plays an important role in the development of the central nervous system. Aggregation of embryonic carcinoma P19 cells with retinoic acid (RA) results in the development of neurons, glia and fibroblast-like cells. In this report, we have shown that Sox6 mRNA increased rapidly in P19 cells during RA induction and then decreased during the differentiation of P19 into neuronal cells. To explore the possible roles of Sox6 during this process, stably Sox6-overexpressing P19 cell lines (P19[Sox6]) were established. These P19[Sox6] had acquired both characteristics of the wild-type P19 induced by RA. First, P19[Sox6] cells showed a marked cellular aggregation in the absence of RA. Second, P19[Sox6] could differentiate into microtubule-associated protein 2 (MAP2)-expressing neuronal cells in the absence of RA. Sox6 expression could cause the activation of endogenous genes including the neuronal transcription factor Mash-1, the neuronal development-related gene Wnt-1, the neuron-specific cell adhesion molecule N-cadherin, and the neuron-specific protein MAP2, resulting in neurogenesis. Moreover, E-cadherin, a major cell adhesion molecule of wild-type P19, was strongly induced by Sox6, resulting in cellular aggregation without RA. Thus Sox6 may play a critical role in cellular aggregation and neuronal differentiation of P19 cells.
    FEBS Letters 03/2004; 560(1-3):192-8. · 3.58 Impact Factor
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    ABSTRACT: A cDNA encoding rat homologue of the previously characterized mouse Sox6 was isolated by a polymerase chain reaction (PCR) cloning strategy. Comparison of this eDNA with homologous mouse, human and rainbow trout cDNA exhibited an overall amino acid sequence identity of 99.6, 89.3 and 76.3% respectively. The leucine-zipper and HMG-box motif were almost completely conserved between these homologues. The expression of Sox6 was determined in rat by Northern hybridization and Real-time quantitative reverse transcription (RT)-PCR. rSox6 (rat Sox6) was specifically expressed in the neonatal brain and adult testis with Northern blotting. Real-time quantitative RT-PCR for the determination of Sox6 mRNA was examined. The rSox6 was expressed in the neonatal brain and adult testis as well as by Northern blotting and also expressed in the adult eyeball and slightly in the ovary.
    Biological & Pharmaceutical Bulletin 07/2002; 25(6):705-9. · 1.85 Impact Factor
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    ABSTRACT: Protein phosphorylation plays many important roles in cell functions and cell differentiation. To clarify the roles of protein phosphorylation in early embryonic development in mice, 2-cell embryos were cultured in the presence of various protein phosphatase inhibitors such as calyculin A, okadaic acid, cyclosporin A, tacrolimus (FK506) and benzyl-phosphonic acid. Calyculin A potently inhibited the 2-cell cleavage to the 4-cell stage. The concentration for 50% inhibition was 0.26 nM. At the same time, we found that calyculin A-treated 2-cell embryos showed a morula-like shape at a concentration of 2 nM in 24 h. It is well known that E-cadherin plays a key role in the compaction of late 8-cell stage embryos. In this report, we observed the distribution of E-cadherin protein using anti-E-cadherin antibody with a fluorescence microscope, and also evaluated the relative E-cadherin mRNA content at various stages of embryos by RT-PCR and ABI PRISM 7700 System (a real time PCR apparatus). The fluorescence intensity of E-cadherin increased along with the embryonic development. During the embryonic development from the 2-cell stage to the blastocyst stage, the relative E-cadherin mRNA content greatly increased in a time-dependent manner, while the mRNA did not increase with the addition of calyculin A at the 2-cell stage. Therefore, we observed the localization of the E-cadherin protein in calyculin A-treated embryos with a laser microscope. The distribution pattern of E-cadherin was altered by the addition of calyculin A from a scattered pattern throughout the embryos to a localized pattern at the cell-cell boundary region. These results strongly suggest that the distribution of E-cadherin protein is regulated by protein phosphorylation and/or dephosphorylation.
    Biological & Pharmaceutical Bulletin 03/2002; 25(2):179-83. · 1.85 Impact Factor
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    ABSTRACT: The immunocytochemical localization of beta-citryl-L-glutamate (beta-CG) in primary neuronal cells and in the differentiation of P19 cells was examined. 1: Cells with the morphological features of neurons in the primary culture were specifically stained with the anti-beta-CG antibody both in neurites and in the cell body. 2: The neuronal cells differentiated from P19 cells were distinctly stained with the anti-beta-CG antibody both in neurites and in the cell body, while the non-neuronal cells were not. 3: The concentration of beta-CG was low in the P19 cells, but increased significantly with the differentiation of P19 cells into neurons. It was shown that beta-CG was localized exclusively in neurons. These findings suggest that beta-CG plays functional roles in the differentiation and growth of neuron.
    Biological & Pharmaceutical Bulletin 12/2000; 23(11):1287-92. · 1.85 Impact Factor
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    ABSTRACT: Beta-citryl-L-glutamate (beta-CG) concentration was determined by HPLC during the differentiation of bovine lens epithelial cells into lens fiber cells in culture. beta-CG increased from 1 to 4 weeks of culture and then decreased slightly, while alpha-crystallin, a marker of lens cell differentiation, increased rapidly 4 weeks after the culture and continued to increase gradually until week 11. In addition, the localization of beta-CG was immunohistochemically examined using anti-beta-CG antibody. Cells around lentoid bodies were stained with anti-beta-CG antibody, whereas cells in the bodies were stained strongly with anti-gamma-crystallin antibody. These findings suggest that beta-CG accumulated immediately before the differentiation of the bovine lens epithelial cells into lens fiber cells and may play a role in regulating the differentiation of lens cells.
    Biological & Pharmaceutical Bulletin 07/2000; 23(6):704-7. · 1.85 Impact Factor
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    ABSTRACT: A novel assay for a peroxisomal beta-oxidation enzyme by sandwich ELISA using a monoclonal antibody (RPX-5) against purified rat liver peroxisomes was developed. Immunoblot analysis revealed that RPX-5 recognized a 78 Kd protein, which is a peroxisomal bifunctional enzyme (PBE) in the beta-oxidation pathway. Immunoprecipitation by RPX-5 and the resulting reduction of PBE activity were dependent on RPX-5 concentrations. Sandwich ELISA using RPX-5 could be used to assay PBE in the range of 30 to 2000 ng protein/ml. In rat hepatocyte cultures, the PBE amount by this assay correlated well with PBE activity, with correlation coefficients of 0.965. Studying the mechanisms of peroxisomal induction, patterns of peroxisomal induction were examined by co-treatment of rat hepatocytes with various peroxisome proliferators (PxPs). Treatment with clofibrate and bezafibrate resulted in neither an additive nor synergistic effect on PBE level. On the other hand, co-treatment with either bezafibrate-Wy-14,643 or clofibrate-MEHP(mono(2-ethylhexyl)phthalate) both resulted in an additive effect. From these results, it is suggested that PxPs of the fibrate group may exert their functions via a common process, and non-fibrate PxPs via a different process in hepatocytes. The cognition site for peroxisome proliferators, therefore, might not involve a single site for inducing peroxisomal enzymes.
    Biological & Pharmaceutical Bulletin 02/2000; 23(1):12-6. · 1.85 Impact Factor
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    ABSTRACT: Expression of kininogen mRNAs has been studied in cultures of three different types of cells in rat brain, including neurons and astrocytes from cerebral cortex and meningeal cells from the leptomeninges/choroid plexus. T-kininogen mRNA was expressed by meningeal cells, but not by neurons and astrocytes, and the expression in meningeal cells was enhanced by culture with prostaglandin E2 (PGE2) or dibutyryl cAMP (Bt2cAMP). Low-molecular-weight kininogen mRNA was not detected in these cultures of cells, even after treatment with PGE2. Although expression of high-molecular-weight kininogen mRNA was very low in these cultures of cells, PGE2 or Bt2cAMP markedly stimulated its expression in cultures of meningeal cells and slightly in neurons, but not in astrocytes. We also found that expression of plasma kallikrein mRNA was strong in cultures of meningeal cells and slight in astrocytes, but absent in neurons. These results suggest that cells in the leptomeninges/choroid plexus are major sources of kininogens in rat brain which may function as precursor proteins for kinins and/or potent cysteine proteinase inhibitors during cerebral inflammation.
    Immunopharmacology 12/1999; 45(1-3):121-6.
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    ABSTRACT: Tissue distribution of bikunin mRNA, which encodes a Kunitz-type serine protease inhibitor of the inter-alpha-inhibitor family (IalphaI), was studied in rats and mice by the reverse-transcripsion polymerase chain reaction (RT-PCR). We found that the liver as well as other tissues, such as the kidney, testis and adrenal gland, expressed bikunin mRNA. Although signals of bikunin mRNA were faint in the whole brain of rats and mice, distinct signals were found in limited portions of rat brain, such as the hippocampus, cerebral cortex and pituitary, but undetectable in cerebellum, medulla oblongata, hypothalamus, striatum, midbrain and choroid plexus. In three distinct types of cells, such as neurons, astrocytes and meningeal cells, in primary cultures isolated from the cerebral cortex and meninges of 1-day-old newborn rats, only neurons positively expressed bikunin mRNA. These results suggest that, in addition to peripheral tissues, neurons in the hippocampus and cerebral cortex produce bikunin, suggesting a potential role of bikunin/IalphaI family in these brain regions.
    Life Sciences 02/1999; 65(8):757-62. · 2.56 Impact Factor
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    ABSTRACT: The beta-CG concentration in the chicken brain was high during embryonic development and decreased rapidly to a lower level close to hatching, while the concentration in the eyeball which was also high during the embryonic life retained a fairly high level after hatching. The distribution of beta-CG in the bovine eye was determined. About 95% of total beta-CG content in the whole eye was localized in the lens. However, the distribution of beta-CG in the eye varied depending on species. beta-CG was exclusively localized in the lens in the eyes of fish and mammals, but distributed in both lens and retina in frogs. The molecule was localized in the retina rather than the lens in the chicken eye, although the concentrations was extremely low compared to those in the mammalian, amphibian and fish eyes. It was found that beta-CG is present ubiquitously in the lens or retina in various species. The distribution of beta-CG in the bovine lens was determined in the three cortex regions and nucleus. beta-CG was present at the highest concentration in the equatorial cortex, at a moderate concentration in the posterior and anterior cortex, and at the lowest concentration in the nucleus. Similar distribution patterns were also found in the rabbit and rat lens. When embryonic chick lens epithelial cells were cultured in the presence of fetal calf serum, the cells elongated, differentiated into fiber cells and formed lentoid bodies. The cells of lentoid bodies were stained strongly by the anti-beta-CG antibody, while cells around the structures were not. In addition, the beta-CG content in the lenses from the galactose cataractous rat decreased to about 20-30% of that in the normal lens. These findings suggest that beta-CG may play a role in the differentiation of epithelial cells into fiber cells.
    Experimental Eye Research 11/1995; 61(4):403-11. · 3.03 Impact Factor
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    ABSTRACT: beta-Citryl-L-glutamate-hydrolysing enzyme (beta-CGHE) was purified from rat testis particulate fraction 13,000-fold, at a yield of 7%. The enzyme was purified by ammonium sulfate fractionation, hydroxyapatite, chelating Sepharose, beta-CG-Sepharose affinity chromatography and Sephacryl S-300 gel filtration. The purified enzyme usually migrated as two periodic acid Schiff's-stained bands on native polyacrylamide gel-electrophoresis (PAGE) with molecular weights of 350 and 420 kDa. Both bands hydrolyzed beta-citryl-L-glutamate (beta-CG) to citrate and glutamate. The 420 kDa band was changed by digestion with N-glycosidase F, into a 350 kDa band on native PAGE. The purified enzyme was composed of 90, 100, 115 and 130 kDa subunits on SDS-PAGE under non-reduced conditions. The purified enzyme was pharmacologically similar to the beta-CGHE activity partially purified from rat testis. This enzyme required manganese ions for full activity and it was strongly inhibited by nucleotides such as ATP or GTP and phosphate ions. beta-CGHE was also potently inhibited by an excitatory amino acid agonist, L-quisqualate, but not by another agonists, N-methyl-D-aspartate and kinate. It had high substrate specificity for beta-CG. The antibodies against the purified enzyme reacted mainly to the 115 kDa band on the SDS-PAGE and precipitated the enzyme activity from the crude and purified enzyme solution.
    Biochimica et Biophysica Acta 08/1995; 1250(1):35-42. · 4.66 Impact Factor
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    ABSTRACT: This study was conducted to increase the in vivo thrombopoietic activity of interleukin-6 (IL-6). Recombinant human IL-6 was covalently conjugated with N-succinimidyl succinate monomethoxy polyethylene glycol (PEG). The in vitro bioactivity of the PEG-modified IL-6 was reduced with increase in its degree of PEG modification, but the in vivo thrombopoietic activity of PEG-modified IL-6 was markedly increased compared to unmodified IL-6. In particular, modified IL-6, in which 54% of the 14 lysine amino groups were coupled with PEG, showed > 10 times greater thrombopoietic effect in vivo than unmodified IL-6. The area under the serum concentration curve of PEG-modified IL-6 after subcutaneous injection was > 17 times larger than that of unmodified IL-6. Chemical attachment of PEG to IL-6 thus increased the bioavailability of IL-6, and may facilitate its potential therapeutic use.
    Journal of Controlled Release. 03/1995;
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    ABSTRACT: This study was conducted to determine the mechanisms for the enhanced inhibitory effect of cell-adhesive peptides conjugated to polyethylene glycol (PEG) on tumor metastasis. Tyr-Ile-Gly-Ser-Arg (YIGSR), a laminin-derived peptide, conjugated with amino-PEG (YIGSR-aPEG) inhibited lung metastasis of B16-BL6 melanoma cells more effectively than unconjugated YIGSR peptide. [125I]-YIGSR-aPEG and native [125I]-YIGSR showed similar biphasic elimination and profiles after intravenous injection into C57BL/6 mice. Both [125I]-YIGSR and [125I]-YIGSR-aPEG expressed similar plasma half-lives and organ distributions. The radioactivity of both compounds was transported rapidly from the blood to the kidneys, and immediately excreted into the urine. [125I]-YIGSR was almost completely degraded in the urine, but [125I]-YIGSR-aPEG was not. In an in vitro stability assay, [125I]-YIGSR was degraded immediately upon incubation with mouse serum, whereas [125I]-YIGSR-aPEG was not degraded after 180 min incubation in mouse serum. These findings indicate that the enhanced inhibitory effect of YIGSR-aPEG on lung metastasis might be due to its increased stability in the blood.
    Invasion and Metastasis 02/1995; 15(3-4):156-62.
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    ABSTRACT: Complete regression of solid tumors was achieved by plural intravenous (i.v.) administrations of polyethylene glycol (PEG)-modified tumor necrosis factor-alpha (TNF-alpha), prepared by covalently modifying natural human TNF-alpha with N-succinimidyl succinate PEG. The anti-tumor efficacy of PEG-modified TNF-alpha (MPEG-TNF-alpha), in which 56% of the TNF-alpha-lysine residues were coupled with PEG, was compared with that of native TNF-alpha in the Meth-A murine fibrosarcoma model. MPEG-TNF-alpha and native TNF-alpha were given as i.v. injections twice a week for 2 weeks. The anti-tumor activity of MPEG-TNF-alpha was dose-dependent and was far superior to that of native TNF-alpha. Complete regression was observed in 3 of the 8 mice administered native TNF-alpha at the dose of 10,000 JRU (Japan reference unit), but 4 of the 5 remaining mice died during the therapeutic period. At 5,000 JRU of native TNF-alpha, no case of complete regression was observed. By contrast, complete regression was obtained in all 10 mice given 200 JRU of MPEG-TNF-alpha. No side-effects were observed at the dose of 500 JRU of MPEG-TNF-alpha, which was 2.5 times the minimal dose (200 JRU) of MPEG-TNF-alpha required for complete regression in all treated mice. MPEG-TNF-alpha appears to have potential as a candidate anti-tumor therapeutic agent.
    Japanese journal of cancer research: Gann 01/1995; 85(12):1185-8.

Publication Stats

118 Citations
46.56 Total Impact Points

Institutions

  • 1993–2013
    • Kobe Gakuin University
      • Faculty of Pharmaceutical Sciences
      Kōbe-shi, Hyogo-ken, Japan
  • 1995
    • Osaka University
      • Division of Molecular Pharmaceutical Science
      Suita, Osaka-fu, Japan
  • 1994
    • Osaka University of Pharmaceutical Sciences
      • Faculty of Pharmaceutical Sciences
      Ōsaka, Ōsaka, Japan
  • 1992
    • Ehime University
      • School of Medicine
      Matuyama, Ehime, Japan