49 results on '"Y. Kasama"'
Search Results
2. Brief communication: body composition and hidden obesity in people living with HIV on antiretroviral therapy
- Author
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K. Konishi, H. Nakagawa, T. Asaoka, Y. Kasamatsu, T. Goto, and M. Shirano
- Subjects
HIV ,Antiretroviral therapy ,Weight gain ,Body composition ,Japan ,Immunologic diseases. Allergy ,RC581-607 - Abstract
Abstract Background Increased incidence of lifestyle diseases as side-effects of antiretroviral therapy (ART) have been reported in people living with HIV (PLWH). Few studies have evaluated obesity and hidden obesity in Japanese PLWH and their association with ART. In order to provide more appropriate drug selection and lifestyle guidance, we investigated the relationship between the effects of HIV infection and ART on the body composition of Japanese PLWH. Methods PLWH who visited the outpatient clinic and had body composition measured using the body composition analyzer InBody 570 were included in this study. Medications, comorbidities, and blood test data were obtained. Body mass index (BMI), body fat percentage, and skeletal muscle mass index (SMI) were measured. Results In this study, 543 patients were included. Based on body shape, patients were classified into a thin group (13), normal weight group (14), hidden obesity group (158), apparent obesity group (14), and obesity group (218). Compared with the normal weight group, the hidden obesity group had a higher prevalence of comorbidities and a lower SMI. Conclusions PLWH are more likely to have obesity than the general population, indicating that hidden obesity is common even among those with a normal BMI. It is important to measure body fat percentage along with body weight, as hidden obesity can be missed. Further investigation of the effects of ART on body composition is needed.
- Published
- 2024
- Full Text
- View/download PDF
3. Extensive first-principles molecular dynamics study on Li encapsulation into C
- Author
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K, Ohno, A, Manjanath, Y, Kawazoe, R, Hatakeyama, F, Misaizu, E, Kwon, H, Fukumura, H, Ogasawara, Y, Yamada, C, Zhang, N, Sumi, T, Kamigaki, K, Kawachi, K, Yokoo, S, Ono, and Y, Kasama
- Abstract
The aim of increasing the production ratio of endohedral C
- Published
- 2018
4. Induced pluripotent stem cell generation-associated point mutations
- Author
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R, Araki, M, Sugiura, Y, Hoki, M, Sunayama, M, Nakamura, Y, Kasama, and M, Abe
- Abstract
The discovery of induced pluripotent stem cells (iPSCs) has the potential to drastically alter the future of medicine. Further, the achievement of cell lineage conversion by gene transduction is expected to make a dramatic contribution to the advancement of basic biology. Currently, various iPSC applications have been the focus of much attention due to their potential in regenerative medicine. Nevertheless, because the molecular mechanisms underlying the creation of these cells have remained elusive, confidence in their safe use in a clinical setting has remained rather shaky. In our present review, we discuss genome integrity during iPSC generation, with a particular focus on point mutations, to further address the issue of whether iPSC generation causes genetic aberrations.
- Published
- 2015
5. STUDIES ON EXPERIMENTAL RICKETS : I. THE OCCURRENCE OF RICKETS IN YOUNG RABBITS BORN OF MOTHERS INFECTED WITH SCHISTOSOMUM JAPONICUM
- Author
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R, Kawamura and Y, Kasama
- Subjects
Article - Abstract
Our observations show that young rabbits born of mothers afflicted with Schistosomum japonicum develop typical rickets. Rickets can also be produced if we infect the young, healthy rabbits with the same parasite. It is natural to suppose that the rachitic changes are caused by the parasite itself. Since, however, a similar disease can be produced in the offspring, when the mother is fed on egg yolk, the causation is not limited to the action of this parasitic toxin alone. The toxin of Schistosoma may disturb the calcium and phosphorus metabolism of bone in young animals, especially in the period of vigorous growth; that is, 20 to 40 days after birth of the rabbits. Or it may exhaust some element important in the calcium and phosphorus metabolism such as vitamin A or D. The fact that exhaustion of the antirachitic factor in the mother causes rickets in the young, as Grant (1924) showed, and that certain low grade infections can exhaust vitamin B as shown by Wedgewood (1924), is in line with this conception. It may be added here that most investigations on rickets have been carried out on rats and dogs. We have found a simple and excellent way of producing rickets in rabbits by dietary deficiency. Concerning this method, we shall report elsewhere.
- Published
- 2009
6. Electronic measurements of alkali metal-encapsulated singlewalled carbon nanotubes produced by plasma ion irradiation
- Author
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Y. Neo, T. Tzumida, Hidenori Mimura, Rikizo Hatakeyama, Takamichi Hirata, Y. Kasama, and K. Omote
- Subjects
Materials science ,Ambipolar diffusion ,chemistry.chemical_element ,Nanotechnology ,Carbon nanotube ,Alkali metal ,Ion ,law.invention ,Chemical engineering ,chemistry ,law ,Caesium ,Electrode ,Field-effect transistor ,Irradiation - Abstract
We report detailed experimental results of the electronic transport properties of Cs-encapsulatcd single-walled carbon nanotubes (SWNTs) produced via plasma ion irradiation method. After fabricating field-effect transistor (FET) configuration using pristine and alkali metal ion irradiated SWNTs as channel, the electronic transport properties of these devices are investigated. As a result, pristine semiconducting SWNTs show p-type transport properties. On the other hand, it is clearly observed that Cs-encapsulated semiconducting SWNTs have n-type transport behavior. This phenomenon can be explained in terms of charge transfer from Cs atoms in SWNTs. Moreover, ambipolar property is obtained by measuring Li-encapsulated SWNTs FET.
- Published
- 2005
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7. Electric transport properties of single-walled carbon nanotubes functionalized by plasma ion irradiation method
- Author
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Y. Kasama, K. Omote, Yung Woo Park, Rikizo Hatakeyama, Y. Neo, Hidenori Mimura, Takamichi Hirata, Goo-Hwan Jeong, Sung Ho Jhang, and Takeshi Izumida
- Subjects
Materials science ,chemistry.chemical_element ,Nanotechnology ,Carbon nanotube ,Plasma ,Temperature measurement ,law.invention ,Ion ,Chemical engineering ,chemistry ,law ,Caesium ,Electrode ,Field-effect transistor ,Irradiation - Abstract
We report experimental results of the electric transport properties of single-walled carbon nanotubes (SWNTs) functionalized by plasma ion irradiation method, where purified SWNTs and Cs-encapsulating SWNTs are used. SWNTs bundles are well dropped between source and drain electrodes of the field effect transistor (FET) configuration. Voltage-current characteristics, gate bias dependence, and measuring temperature dependence are investigated. It is found that purified SWNTs exhibit p-type semiconducting behavior. Transport measurements for Cs encapsulating individual SWNTs have also been performed, the result of which is discussed.
- Published
- 2005
- Full Text
- View/download PDF
8. Purification and characterization of thermostable beta-N-acetylhexosaminidase of Bacillus stearothermophilus CH-4 isolated from chitin-containing compost
- Author
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Mitsuaki Moriguchi, Mamoru Wakayama, Kenji Sakai, Y. Kasama, and M. Narihara
- Subjects
inorganic chemicals ,Stereochemistry ,Molecular Sequence Data ,Applied Microbiology and Biotechnology ,Substrate Specificity ,Geobacillus stearothermophilus ,chemistry.chemical_compound ,Hydrolysis ,Chitin ,Amino Acid Sequence ,chemistry.chemical_classification ,Waste Products ,Bacillaceae ,Ecology ,biology ,Molecular mass ,Chitinases ,biology.organism_classification ,Bacillales ,beta-N-Acetylhexosaminidases ,Molecular Weight ,Kinetics ,Enzyme ,chemistry ,Chitinase ,Urea ,biology.protein ,Sequence Analysis ,Food Science ,Biotechnology ,Nuclear chemistry ,Research Article - Abstract
Thermostable exochitinase was purified to homogeneity from the culture fluid of Bacillus stearothermophilus CH-4, which was isolated from agricultural compost containing shrimp and crabs. The enzyme was a single polypeptide with a molecular mass of 74 kDa, and the N-terminal amino acid sequence was WDKVGVTDLI ISLNIPEADAVVVGMTLQLQALHLY. The enzyme specifically hydrolyzed C-4 beta-anomeric bonding of N-acetylchitooligosaccharides, as well as their p-nitrophenyl (pNP) derivatives. The enzyme also hydrolyzed pNP-beta-N-acetyl-D-galactosaminide (26% of the activity of pNP-beta-N-acetyl-D-glucosaminide). These results indicated that the enzyme is a beta-N-acetylhexosaminidase (EC 3.2.1.52). Kms for acetylchitooligosaccharides were 1 x 10(-4) to 6 x 10(-4) M, while those for the pNP derivatives were 4 x 10(-3) to 8 x 10(-3) M. The optimum temperature of the enzyme was 75 degrees C, and it retained 100 and 28% reactivity after heating at 60 and 80 degrees C, respectively. The enzyme exhibited 15 to 20% activity in a reaction mixture containing 80% organic solvents and maintained 91% of its original activity after exposure to 8 M urea. The optimum and stable pH was around 6.5. Fe2+, Zn2+, and Ca2+ activated the enzyme, but Hg2+ was inhibitory. N-Acetyl-D-glucosamine inhibited the enzyme competitively (Ki = 4.3 x 10(-4) M), whereas N-acetyl-D-galactosamine did not; in contrast, D-glucosamine and D-galactosamine activated it.
- Published
- 1994
9. STUDIES ON EXPERIMENTAL RICKETS
- Author
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Y. Kasama and R. Kawamura
- Subjects
Vitamin ,medicine.medical_specialty ,food.ingredient ,biology ,Offspring ,Immunology ,Rickets ,Cod liver oil ,medicine.disease ,biology.organism_classification ,Phosphorus metabolism ,Malnutrition ,chemistry.chemical_compound ,food ,Endocrinology ,chemistry ,Internal medicine ,Yolk ,medicine ,Immunology and Allergy ,Schistosoma - Abstract
Our observations show that young rabbits born of mothers afflicted with Schistosomum japonicum develop typical rickets. Rickets can also be produced if we infect the young, healthy rabbits with the same parasite. It is natural to suppose that the rachitic changes are caused by the parasite itself. Since, however, a similar disease can be produced in the offspring, when the mother is fed on egg yolk, the causation is not limited to the action of this parasitic toxin alone. The toxin of Schistosoma may disturb the calcium and phosphorus metabolism of bone in young animals, especially in the period of vigorous growth; that is, 20 to 40 days after birth of the rabbits. Or it may exhaust some element important in the calcium and phosphorus metabolism such as vitamin A or D. The fact that exhaustion of the antirachitic factor in the mother causes rickets in the young, as Grant (1924) showed, and that certain low grade infections can exhaust vitamin B as shown by Wedgewood (1924), is in line with this conception. It may be added here that most investigations on rickets have been carried out on rats and dogs. We have found a simple and excellent way of producing rickets in rabbits by dietary deficiency. Concerning this method, we shall report elsewhere.
- Published
- 1925
- Full Text
- View/download PDF
10. Structural analysis of polyglycerol fatty acid ester-coenzyme Q10 aggregates in solution.
- Author
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Iwase H, Kobayashi J, Kasama Y, Fujii W, and Nanbu H
- Subjects
- Scattering, Small Angle, X-Ray Diffraction, Esters chemistry, Water, Micelles, Fatty Acids chemistry
- Abstract
Polyglycerol fatty acid esters (PGFEs) are common food additives. PGFE-based formulations exhibit high structural stability, however, the stability mechanism of the micellar structures has not been yet elucidated. In this study, nanostructural analysis was performed using small-angle neutron and X-ray scattering (SANS and SAXS) measurements to reveal the mechanism of the structural stability of PGFE-coenzyme Q10 (CoQ10) mixtures as a CoQ10 formulation. Pure PGFE formed multilamellar vesicles, whereas PGFE-CoQ10 formed spherical micelles. Furthermore, when the amount of added water increased, the PGFE-CoQ10 micellar size and the amount of water in the micelles remained unchanged. A model-fitting analysis of the SANS results suggested that the CoQ10 molecules were introduced between the surfactants, forming a palisade-type structure. The high structural stability of the PGFE-CoQ10 micelles was attributed to two factors: proper spreading of the hydrophilic head chains and inhibition of the change of the amount of water inside the micelles by the PGFE heads and quinone ring of CoQ10. This indicates that PGFE-CoQ10 can function in water while maintaining the micellar structure formed in the storage solution. The findings of this study are important for the safety and nano-hazard aspects of PGFE-CoQ10 formulations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
- Published
- 2024
- Full Text
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11. Heterospin frustration in a metal-fullerene-bonded semiconductive antiferromagnet.
- Author
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Shen Y, Cui M, Takaishi S, Kawasoko H, Sugimoto K, Tsumuraya T, Otsuka A, Kwon E, Yoshida T, Hoshino N, Kawachi K, Kasama Y, Akutagawa T, Fukumura T, and Yamashita M
- Abstract
Lithium-ion-encapsulated fullerenes (Li
+ @C60 ) are 3D superatoms with rich oxidative states. Here we show a conductive and magnetically frustrated metal-fullerene-bonded framework {[Cu4 (Li@C60 )(L)(py)4 ](NTf2 )(hexane)}n (1) (L = 1,2,4,5-tetrakis(methanesulfonamido)benzene, py = pyridine, NTf2 - = bis(trifluoromethane)sulfonamide anion) prepared from redox-active dinuclear metal complex Cu2 (L)(py)4 and lithium-ion-encapsulated fullerene salt (Li+ @C60 )(NTf2 - ). Electron donor Cu2 (L)(py)2 bonds to acceptor Li+ @C60 via eight Cu‒C bonds. Cu-C bond formation stems from spontaneous charge transfer (CT) between Cu2 (L)(py)4 and (Li+ @C60 )(NTf2 - ) by removing the two-terminal py molecules, yielding triplet ground state [Cu2 (L)(py)2 ]+ (Li+ @C60 •- ), evidenced by absorption and electron paramagnetic resonance (EPR) spectra, magnetic properties and quantum chemical calculations. Moreover, Li+ @C60 •- radicals (S = ½) and Cu2+ ions (S = ½) interact antiferromagnetically in triangular spin lattices in the absence of long-range magnetic ordering to 1.8 K. The low-temperature heat capacity indicated that compound 1 is a potential candidate for an S = ½ quantum spin liquid (QSL)., (© 2022. The Author(s).)- Published
- 2022
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12. Direct Visualization of Nearly Free Electron States Formed by Superatom Molecular Orbitals in a Li@C 60 Monolayer.
- Author
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Sumi N, Kuklin AV, Ueno H, Okada H, Ogawa T, Kawachi K, Kasama Y, Sasaki M, Avramov PV, Ågren H, and Yamada Y
- Abstract
Using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations, we directly determine the spatial and energetic distributions of superatom molecular orbitals (SAMOs) of an Li@C
60 monolayer adsorbed on a Cu(111) surface. Utilizing a weakly bonded [Li+ @C60 ] NTf2 - (NTf2 - : bis(trifluoromethanesulfonyl)imide) salt makes it possible to produce a Li@C60 monolayer with high concentration of Li@C60 molecules. Because of the very uniform adsorption geometry of Li@C60 on Cu(111), the pz -SAMO, populated above the upper hemisphere of the molecule, exhibits an isotropic and delocalized nature, with an energy that is significantly lower compared to that of C60 . The isotropic overlapping of pz -SAMOs in the condensed monolayer of Li@C60 results in a laterally homogeneous STM image contributing to the formation of a free-electron-like states. These findings make an important step toward further basic research and applicative utilization of Li@C60 SAMOs.- Published
- 2021
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13. HER2-antigen-specific humoral immune response in breast cancer lymphocytes transplanted in hu-PBL hIL-4 NOG mice.
- Author
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Ohno Y, Ohshima S, Miyamoto A, Kametani F, Ito R, Tsuda B, Kasama Y, Nakada S, Kashiwagi H, Seki T, Yasuda A, Ando K, Ito M, Tokuda Y, and Kametani Y
- Subjects
- Adult, Aged, Aged, 80 and over, Animals, Antibodies, Neoplasm metabolism, Antibody Formation drug effects, Antibody Formation immunology, B-Lymphocytes drug effects, B-Lymphocytes immunology, Blood Proteins metabolism, Breast Neoplasms pathology, Female, Humans, Interleukin-4 metabolism, Lymphocytes drug effects, Mice, Middle Aged, Nivolumab pharmacology, Programmed Cell Death 1 Receptor metabolism, Spleen cytology, T-Lymphocytes drug effects, T-Lymphocytes immunology, Tissue Donors, Antigens, Neoplasm metabolism, Breast Neoplasms immunology, Immunity, Humoral drug effects, Lymphocytes immunology, Receptor, ErbB-2 metabolism
- Abstract
The status of humoral immunity of cancer patients is not clear compared to cellular immunity because the ability of specific antibody production is difficult to analyze in vitro. We previously developed a humanized mouse model to evaluate antigen-specific antibody production by transplanting human peripheral blood mononuclear cells (PBMCs) into NOG-hIL-4-Tg mice (hu-PBL hIL-4 NOG). In this study, these mice were transplanted with PBMCs derived from breast cancer patients (BC) and immunized with a human epidermal growth factor receptor 2 (HER2) peptide, CH401MAP, to analyze humoral immunity of BCs. The hu-PBL hIL-4 NOG mice recapitulated immune environment of BCs as the ratio of CD8+/CD4+T cells was lower and that of PD-1 + T cells was higher compared to healthy donors (HDs). Diverse clusters were detected in BC-mouse (BC-M) plasma components involving immunoglobulins and complements unlike HD-M, and there was a significant diversity in CH401MAP-specific IgG titers in BC-M. The number of B cell clones producing high CH401MAP-specific IgG was not increased by immunization in BC-M unlike HD-M. These results demonstrated that the humoral immunity of BCs appeared as diverse phenotypes different from HDs in hu-PBL hIL-4 NOG mice, which may provide important information for the study of personalized medicine.
- Published
- 2021
- Full Text
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14. Cocrystals of Li + encapsulated fullerenes and Tb(iii) double-decker single molecule magnet in a quasi-kagome lattice.
- Author
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Iwami H, Xing J, Nakanishi R, Horii Y, Katoh K, Breedlove BK, Kawachi K, Kasama Y, Kwon E, and Yamashita M
- Abstract
Cocrystallization of a lithium ion encapsulated fullerene Li
+ @C60 with a terbium(iii) phthalocyaninato porphyrinato double-decker single-molecule magnet [Tb(Pc)(OEP)] is reported. The cocrystal, containing PF6 - as a counter anion, packs in a quasi-kagome lattice, which leads to intermolecular ferromagnetic interactions as well as the modulation of the single-molecule magnet (SMM) properties.- Published
- 2020
- Full Text
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15. The thermodynamic properties and molecular dynamics of [Li + @C 60 ](PF 6 - ) associated with structural phase transitions.
- Author
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Suzuki H, Ishida M, Otani C, Kawachi K, Kasama Y, Kwon E, Miyazaki Y, and Nakano M
- Abstract
Calorimetric and terahertz-far-infrared (THz-FIR) spectroscopic and infrared (IR) spectroscopic measurements were conducted for [Li+@C60](PF6-) at temperatures between 1.8 and 395 K. [Li+@C60](PF6-) underwent a structural phase transition at around 360 K accompanied by the orientational order-disorder transition of Li+@C60 and PF6-. The transition occurred in a step-wise manner. The total transition entropy (ΔtrsS) of 40.1 ± 0.4 J K-1 mol-1 was smaller than that of the orientational order-disorder transition in a pristine C60 crystal (ΔtrsS = 45.4 ± 0.5 J K-1 mol-1). Thus, the orientational disorder of Li+@C60 in the high-temperature phase of [Li+@C60](PF6-) was much less excited than that of the pristine C60 owing to the Coulombic interactions, which stabilized the ionic crystal lattice of [Li+@C60](PF6-). At T < 100 K, upon cooling, Li+ ions were trapped in two pockets on the inner surface of C60, and no phase transition was observed. Finally, the Li+ ions achieved a complete order at 24 K through antiferroelectric transition. The ΔtrsS value of 4.6 ± 0.4 J K-1 mol-1 was slightly smaller than R ln 2 = 5.76 J K-1 mol-1 expected for the two-site order-disorder transition. The extent of the Li+ motion in the C60 cage was related to the selection rule in the THz-FIR and IR spectroscopy of the C60 internal vibrations, because a C60 cage should be polarized by the Li+ ion. It is shown that the local symmetry of the caged molecule can be modified by the rotational or hopping motion of the encaged ions.
- Published
- 2019
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16. Extensive first-principles molecular dynamics study on Li encapsulation into C 60 and its experimental confirmation.
- Author
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Ohno K, Manjanath A, Kawazoe Y, Hatakeyama R, Misaizu F, Kwon E, Fukumura H, Ogasawara H, Yamada Y, Zhang C, Sumi N, Kamigaki T, Kawachi K, Yokoo K, Ono S, and Kasama Y
- Abstract
The aim of increasing the production ratio of endohedral C
60 by impinging foreign atoms against C60 is a crucial matter of the science and technology employed towards industrialization of these functional building block materials. Among these endohedral fullerenes, Li+ @C60 exhibits a wide variety of physical and chemical phenomena and has the potential to be applicable in areas spanning the medical field to photovoltaics. However, currently, Li+ @C60 can be experimentally produced with only ∼1% ratio using the plasma shower method with a 30 eV kinetic energy provided to the impinging Li+ ion. From extensive first-principles molecular dynamics simulations, it is found that the maximum production ratio of Li+ @C60 per hit is increased to about 5.1% (5.3%) when a Li+ ion impinges vertically on a six-membered ring of C60 with 30 eV (40 eV) kinetic energy, although many C60 molecules are damaged during this collision. On the contrary, when it impinges vertically on a six-membered ring with 10 eV kinetic energy, the production ratio remains at 1.3%, but the C60 molecules are not damaged at all. On the other hand, when the C60 is randomly oriented, the production ratio reduces to about 3.7 ± 0.5%, 3.3 ± 0.5%, and 0.2 ± 0.03% for 30 eV, 40 eV, and 10 eV kinetic energy, respectively. Based on these observations we demonstrate the possibility of increasing the production ratio by fixing six-membered rings atop C60 using the Cu(111) substrate or UV light irradiation. In order to assess the ideal experimental production ratio, the7 Li solid NMR spectroscopy measurement is also performed for the multilayer randomly oriented C60 sample irradiated by Li+ using the plasma shower method combined with inductively coupled plasma atomic emission spectroscopy (ICP-AES). Time-of-flight mass spectroscopy measurements are also performed to cross check whether Li+ @C60 molecules are produced in the sample. The resulting experimental estimate, 4% for 30 eV incident kinetic energy, fully agrees with our simulation results mentioned above, suggesting the consistency and accuracy of our simulations and experiments.- Published
- 2018
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17. Structure of the Microemulsion of Polyglycerol Polyricinoleate Encapsulating Vitamin E.
- Author
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Matsuoka J, Kusano T, Kasama Y, Tominaga E, Kobayashi J, Fujii W, Iwase H, Shibayama M, and Nanbu H
- Subjects
- Emulsions, Glycerol chemistry, Micelles, Rheology, Scattering, Small Angle, Viscosity, X-Ray Diffraction, Glycerol analogs & derivatives, Ricinoleic Acids chemistry, Vitamin E chemistry
- Abstract
The structures of micelles and microemulsions consisting of polyglycerol polyricinoleate (PGPR) were investigated by small-angle X-ray scattering (SAXS) and rheological measurements. The SAXS results show that amphiphilic PGPR molecules form stable micelles in glycerol. When vitamin E is added to the PGPR micelles, it is encapsulated in the micelles and forms an emulsion. These micelles are stable towards mechanical shearing up to a shear rate of 1000 s
-1 , with shear thinning occurring in the emulsion above 100 s-1 , indicating that the emulsion may undergo break up by shearing, but recovers the structure by releasing shear strain.- Published
- 2017
- Full Text
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18. Hotspots of De Novo Point Mutations in Induced Pluripotent Stem Cells.
- Author
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Yoshihara M, Araki R, Kasama Y, Sunayama M, Abe M, Nishida K, Kawaji H, Hayashizaki Y, and Murakawa Y
- Subjects
- Animals, Cell Line, Cellular Reprogramming, Heterochromatin genetics, Humans, Induced Pluripotent Stem Cells metabolism, Mice, Mutation Rate, Polymorphism, Single Nucleotide, Induced Pluripotent Stem Cells cytology, Point Mutation
- Abstract
Induced pluripotent stem cells (iPSCs) are generated by direct reprogramming of somatic cells and hold great promise for novel therapies. However, several studies have reported genetic variations in iPSC genomes. Here, we investigated point mutations identified by whole-genome sequencing in mouse and human iPSCs in the context of epigenetic status. In contrast to disease-causing single-nucleotide polymorphisms, de novo point mutations introduced during reprogramming were underrepresented in protein-coding genes and in open chromatin regions, including transcription factor binding sites. Instead, these mutations occurred preferentially in structurally condensed lamina-associated heterochromatic domains, suggesting that chromatin organization is a factor that can bias the regional mutation rate in iPSC genomes. Mutation signature analysis implicated oxidative stress associated with reprogramming as a likely cause of point mutations. Altogether, our study provides deeper understanding of the mutational landscape of iPSC genomes, paving an important way toward the translation of iPSC-based cell therapy., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
- Full Text
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19. The Number of Point Mutations in Induced Pluripotent Stem Cells and Nuclear Transfer Embryonic Stem Cells Depends on the Method and Somatic Cell Type Used for Their Generation.
- Author
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Araki R, Mizutani E, Hoki Y, Sunayama M, Wakayama S, Nagatomo H, Kasama Y, Nakamura M, Wakayama T, and Abe M
- Subjects
- Animals, Embryo, Mammalian cytology, Embryonic Stem Cells metabolism, Fibroblasts cytology, Fibroblasts metabolism, Gene Frequency genetics, Induced Pluripotent Stem Cells metabolism, Mice, Inbred C57BL, Open Reading Frames genetics, Polymorphism, Single Nucleotide genetics, Sequence Analysis, DNA, Tail, Cell Culture Techniques methods, Embryonic Stem Cells cytology, Induced Pluripotent Stem Cells cytology, Nuclear Transfer Techniques, Point Mutation genetics
- Abstract
Induced pluripotent stem cells hold great promise for regenerative medicine but point mutations have been identified in these cells and have raised serious concerns about their safe use. We generated nuclear transfer embryonic stem cells (ntESCs) from both mouse embryonic fibroblasts (MEFs) and tail-tip fibroblasts (TTFs) and by whole genome sequencing found fewer mutations compared with iPSCs generated by retroviral gene transduction. Furthermore, TTF-derived ntESCs showed only a very small number of point mutations, approximately 80% less than the number observed in iPSCs generated using retrovirus. Base substitution profile analysis confirmed this greatly reduced number of point mutations. The point mutations in iPSCs are therefore not a Yamanaka factor-specific phenomenon but are intrinsic to genome reprogramming. Moreover, the dramatic reduction in point mutations in ntESCs suggests that most are not essential for genome reprogramming. Our results suggest that it is feasible to reduce the point mutation frequency in iPSCs by optimizing various genome reprogramming conditions. We conducted whole genome sequencing of ntES cells derived from MEFs or TTFs. We thereby succeeded in establishing TTF-derived ntES cell lines with far fewer point mutations. Base substitution profile analysis of these clones also indicated a reduced point mutation frequency, moving from a transversion-predominance to a transition-predominance. Stem Cells 2017;35:1189-1196., (© 2017 AlphaMed Press.)
- Published
- 2017
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20. Rotational dynamics of Li + ions encapsulated in C 60 cages at low temperatures.
- Author
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Suzuki H, Ishida M, Yamashita M, Otani C, Kawachi K, Kasama Y, and Kwon E
- Abstract
Li
+ ions encapsulated in fullerene C60 cages (Li+ @C60 ) are expected to be suitable as molecular switches that respond to local electric fields. In this study, the rotational dynamics of Li+ ions in C60 cages at low temperatures are experimentally revealed for the first time using terahertz absorption spectroscopy. In crystalline [Li+ @C60 ](PF6 - ), the Li+ ion rotates in the carbon cage even at 150 K. The rotational mode gradually changes into a librational mode below 120 K, which is associated with the localization of Li+ ions due to the electrostatic interactions with its screening image charge on the C60 cage as well as with the neighboring Li+ @C60 and PF6 - ions. A simple rotational/librational energy scheme for the Li+ ions successfully explains the spectroscopic results, and the potential of Li+ @C60 as a molecular switch is discussed based on the energy scheme.- Published
- 2016
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21. Multiple Human Tracking Using Binary Infrared Sensors.
- Author
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Miyazaki T and Kasama Y
- Abstract
To create a context-aware environment, human locations and movement paths must be considered. In this paper, we propose an algorithm that tracks human movement paths using only binary sensed data obtained by infrared (IR) sensors attached to the ceiling of a room. Our algorithm can estimate multiple human movement paths without a priori knowledge of the number of humans in the room. By repeating predictions and estimations of human positions and links from the previous human positions to the estimated ones at each time period, human movement paths can be estimated. Simulation-based evaluation results show that our algorithm can dynamically trace human movement paths.
- Published
- 2015
- Full Text
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22. iPS cell generation - associated point mutations.
- Author
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Araki R, Sugiura M, Kasama Y, and Abe M
- Subjects
- Induced Pluripotent Stem Cells, Point Mutation
- Published
- 2015
23. B-cell-intrinsic hepatitis C virus expression leads to B-cell-lymphomagenesis and induction of NF-κB signalling.
- Author
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Kasama Y, Mizukami T, Kusunoki H, Peveling-Oberhag J, Nishito Y, Ozawa M, Kohara M, Mizuochi T, and Tsukiyama-Kohara K
- Subjects
- Animals, B-Lymphocytes metabolism, Cell Nucleus metabolism, Fluorescent Antibody Technique, Gene Expression Regulation, Neoplastic, Hepatitis C genetics, Hepatitis C virology, Lymphoma, B-Cell genetics, Lymphoma, B-Cell pathology, Lymphoma, B-Cell virology, Mice, Transgenic, MicroRNAs genetics, MicroRNAs metabolism, Neoplasm Proteins genetics, Neoplasm Proteins metabolism, Oligonucleotide Array Sequence Analysis, Protein Transport, Software, Transcription Factor RelA metabolism, B-Lymphocytes virology, Hepacivirus physiology, NF-kappa B metabolism, Signal Transduction genetics
- Abstract
Hepatitis C virus (HCV) infection leads to the development of hepatic diseases, as well as extrahepatic disorders such as B-cell non-Hodgkin's lymphoma (B-NHL). To reveal the molecular signalling pathways responsible for HCV-associated B-NHL development, we utilised transgenic (Tg) mice that express the full-length HCV genome specifically in B cells and develop non-Hodgkin type B-cell lymphomas (BCLs). The gene expression profiles in B cells from BCL-developing HCV-Tg mice, from BCL-non-developing HCV-Tg mice, and from BCL-non-developing HCV-negative mice were analysed by genome-wide microarray. In BCLs from HCV-Tg mice, the expression of various genes was modified, and for some genes, expression was influenced by the gender of the animals. Markedly modified genes such as Fos, C3, LTβR, A20, NF-κB and miR-26b in BCLs were further characterised using specific assays. We propose that activation of both canonical and alternative NF-κB signalling pathways and down-regulation of miR-26b contribute to the development of HCV-associated B-NHL.
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- 2014
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24. Induced pluripotent stem cell generation-associated point mutations arise during the initial stages of the conversion of these cells.
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Sugiura M, Kasama Y, Araki R, Hoki Y, Sunayama M, Uda M, Nakamura M, Ando S, and Abe M
- Subjects
- Animals, Cell Line, Chromosome Mapping, Embryonic Stem Cells cytology, Embryonic Stem Cells metabolism, Gene Frequency, Genetic Heterogeneity, Genome, High-Throughput Nucleotide Sequencing, Induced Pluripotent Stem Cells cytology, Mice, Mice, Inbred C57BL, Point Mutation, Sequence Analysis, DNA, Induced Pluripotent Stem Cells metabolism
- Abstract
A large number of point mutations have been identified in induced pluripotent stem cell (iPSC) genomes to date. Whether these mutations are associated with iPSC generation is an important and controversial issue. In this study, we approached this critical issue in different ways, including an assessment of iPSCs versus embryonic stem cells (ESCs), and an investigation of variant allele frequencies and the heterogeneity of point mutations within a single iPSC clone. Through these analyses, we obtained strong evidence that iPSC-generation-associated point mutations occur frequently in a transversion-predominant manner just after the onset of cell lineage conversion. The heterogeneity of the point mutation profiles within an iPSC clone was also revealed and reflects the history of the emergence of each mutation. Further, our results suggest a possible approach for establishing iPSCs with fewer point mutations.
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- 2014
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25. EGFR T790M mutation as a possible target for immunotherapy; identification of HLA-A*0201-restricted T cell epitopes derived from the EGFR T790M mutation.
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Yamada T, Azuma K, Muta E, Kim J, Sugawara S, Zhang GL, Matsueda S, Kasama-Kawaguchi Y, Yamashita Y, Yamashita T, Nishio K, Itoh K, Hoshino T, and Sasada T
- Subjects
- Aged, Amino Acid Sequence, Antineoplastic Agents therapeutic use, Carcinoma, Non-Small-Cell Lung genetics, Carcinoma, Non-Small-Cell Lung immunology, Carcinoma, Non-Small-Cell Lung pathology, Drug Resistance, Neoplasm drug effects, Epitopes, T-Lymphocyte genetics, Epitopes, T-Lymphocyte immunology, ErbB Receptors antagonists & inhibitors, ErbB Receptors immunology, Erlotinib Hydrochloride, Female, Gefitinib, HLA-A2 Antigen immunology, Humans, Leukocytes, Mononuclear cytology, Leukocytes, Mononuclear drug effects, Leukocytes, Mononuclear immunology, Lung Neoplasms genetics, Lung Neoplasms immunology, Lung Neoplasms pathology, Lymphocyte Activation, Male, Middle Aged, Molecular Sequence Data, Mutation, Peptides immunology, Protein Kinase Inhibitors therapeutic use, Quinazolines therapeutic use, Carcinoma, Non-Small-Cell Lung therapy, ErbB Receptors genetics, Gene Expression Regulation, Neoplastic, HLA-A2 Antigen genetics, Immunotherapy methods, Lung Neoplasms therapy, Peptides pharmacology
- Abstract
Treatment with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib and erlotinib, has achieved high clinical response rates in patients with non-small cell lung cancers (NSCLCs). However, over time, most tumors develop acquired resistance to EGFR-TKIs, which is associated with the secondary EGFR T790M resistance mutation in about half the cases. Currently there are no effective treatment options for patients with this resistance mutation. Here we identified two novel HLA-A*0201 (A2)-restricted T cell epitopes containing the mutated methionine residue of the EGFR T790M mutation, T790M-5 (MQLMPFGCLL) and T790M-7 (LIMQLMPFGCL), as potential targets for EGFR-TKI-resistant patients. When peripheral blood cells were repeatedly stimulated in vitro with these two peptides and assessed by antigen-specific IFN-γ secretion, T cell lines responsive to T790M-5 and T790M-7 were established in 5 of 6 (83%) and 3 of 6 (50%) healthy donors, respectively. Additionally, the T790M-5- and T790M-7-specific T cell lines displayed an MHC class I-restricted reactivity against NSCLC cell lines expressing both HLA-A2 and the T790M mutation. Interestingly, the NSCLC patients with antigen-specific T cell responses to these epitopes showed a significantly less frequency of EGFR-T790M mutation than those without them [1 of 7 (14%) vs 9 of 15 (60%); chi-squared test, p = 0.0449], indicating the negative correlation between the immune responses to the EGFR-T790M-derived epitopes and the presence of EGFR-T790M mutation in NSCLC patients. This finding could possibly be explained by the hypothesis that immune responses to the mutated neo-antigens derived from T790M might prevent the emergence of tumor cell variants with the T790M resistance mutation in NSCLC patients during EGFR-TKI treatment. Together, our results suggest that the identified T cell epitopes might provide a novel immunotherapeutic approach for prevention and/or treatment of EGFR-TKI resistance with the secondary EGFR T790M resistance mutation in NSCLC patients.
- Published
- 2013
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26. Genomic polymorphisms in 3β-hydroxysterol Δ24-reductase promoter sequences.
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Salem NE, Saito M, Kasama Y, Ozawa M, Kawabata T, Harada S, Suda H, Asonuma K, El-Gohary A, and Tsukiyama-Kohara K
- Subjects
- Aged, Animals, Carcinoma, Hepatocellular genetics, Carcinoma, Hepatocellular pathology, Cells, Cultured, Female, Hepatitis C, Chronic complications, Hepatitis C, Chronic genetics, Humans, Liver Cirrhosis genetics, Liver Cirrhosis pathology, Liver Neoplasms genetics, Liver Neoplasms pathology, Male, Mice, Middle Aged, Hepatitis C, Chronic pathology, Liver pathology, Nerve Tissue Proteins genetics, Oxidoreductases Acting on CH-CH Group Donors genetics, Polymorphism, Genetic, Promoter Regions, Genetic
- Abstract
It was recently reported by the present team that 3β-hydroxysterol Δ24-reductase (DHCR24) is induced by hepatitis C virus (HCV) infection. In addition, upregulation of DHCR24 impairs p53 activity. In human hepatoma HuH-7 cells, the degree of DHCR24 expression is higher than in normal hepatic cell lines (WRL68) at the transcriptional level. The genomic promoter sequence of DHCR24 was characterized and nucleotide substitutions were observed in HuH-7 cells at nucleotide numbers -1453 (G to A), -1420 (G to T), -488 (A to C) and -200 (G to C). The mutations of these sequences from HuH-7 cell types to WRL68 cell types suppressed DHCR24 gene promoter activity. The sequences were further characterized in hepatocytes from patient tissues. Four tissues from HCV-positive patients with cirrhosis or hepatocellular carcinoma (#1, 2, 3, 5) possessed HuH-7 cell type sequences. Interestingly, one patient with liver cirrhosis (#4) possessed WRL68 cell-type sequences; this patient had been infected with HCV and was HCV negative for 17 years after interferon therapy. Next, the effect of HCV infection on these polymorphisms was examined in humanized chimeric mouse liver and HuH-7 cells. The human hepatocytes possess WRL68 cell type and did not show the nucleotide substitution after HCV infection. The HCV-replicon was removed by interferon treatment and established the cured K4 cells. These cells possess HuH-7 cell type sequences. Thus, this study showed the genomic polymorphism in DHCR24 promoter is not directly influenced by HCV infection., (© 2012 The Societies and Wiley Publishing Asia Pty Ltd.)
- Published
- 2013
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27. Covalently chemical modification of lithium ion-encapsulated fullerene: synthesis and characterization of [Li+@PCBM]PF6(-).
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Matsuo Y, Okada H, Maruyama M, Sato H, Tobita H, Ono Y, Omote K, Kawachi K, and Kasama Y
- Abstract
Covalently organic derivatization of [Li(+)@C60]PF6(-) to obtain Li(+)-encapsulated PCBM, [Li(+)@PCBM]PF6(-), is described. Synthetic procedures, electrochemical properties, light absorption properties, details of isomerization from [5,6]- to [6,6]-isomer, and X-ray crystal structure of [Li(+)@PCBM]PF6(-) are discussed.
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- 2012
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28. Rock-salt-type crystal of thermally contracted C60 with encapsulated lithium cation.
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Aoyagi S, Sado Y, Nishibori E, Sawa H, Okada H, Tobita H, Kasama Y, Kitaura R, and Shinohara H
- Abstract
Rock solid: fullerene-encapsulated Li(+) (Li(+)@C(60)) is an alkaline cation owing to the spherical shape and positive charge. Li(+)@C(60) crystallizes as a rock-salt-type crystal in the presence of PF(6)(-). The orientations of C(60) and PF(6)(-) (orange) are perfectly ordered below 370 K, and Li(+) (purple) hops within the cage. At temperatures below 100 K two Li(+) units are localized at two polar positions within each C(60) ., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2012
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29. Translocase of outer mitochondrial membrane 70 induces interferon response and is impaired by hepatitis C virus NS3.
- Author
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Kasama Y, Saito M, Takano T, Nishimura T, Satoh M, Wang Z, Ali SN, Harada S, Kohara M, and Tsukiyama-Kohara K
- Subjects
- Hep G2 Cells, Hepacivirus immunology, Hepatocytes immunology, Hepatocytes virology, Humans, Immune Evasion, Interferons antagonists & inhibitors, Mitochondrial Membrane Transport Proteins metabolism, Mitochondrial Precursor Protein Import Complex Proteins, Viral Nonstructural Proteins immunology, Hepacivirus pathogenicity, Immune Tolerance, Interferons immunology, Mitochondrial Membrane Transport Proteins immunology, Mitochondrial Membranes immunology, Viral Nonstructural Proteins metabolism
- Abstract
Hepatitis C virus (HCV) elevated expression of the translocase of outer mitochondrial membrane 70 (Tom70). Interestingly, overexpression of Tom70 induces interferon (IFN) synthesis in hepatocytes, and it was impaired by HCV. Here, we addressed the mechanism of this impairment. The HCV NS3/4A protein induced Tom70 expression. The HCV NS3 protein interacted in cells, and cleaved the adapter protein mitochondrial anti-viral signaling (MAVS). Ectopic overexpression of Tom70 could not inhibit this cleavage. As a result, IRF-3 phosphorylation was impaired and IFN-β induction was suppressed. These results indicate that MAVS works upstream of Tom70 and the cleavage of MAVS by HCV NS3 protease suppresses signaling of IFN induction., (Copyright © 2011 Elsevier B.V. All rights reserved.)
- Published
- 2012
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30. Monoclonal antibody 2-152a suppresses hepatitis C virus infection through betaine/GABA transporter-1.
- Author
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Satoh M, Saito M, Takano T, Kasama Y, Nishimura T, Nishito Y, Hirata Y, Arai M, Sudoh M, Kai C, Kohara M, and Tsukiyama-Kohara K
- Subjects
- Animals, Antibodies, Monoclonal immunology, Cell Line, Tumor, GABA Plasma Membrane Transport Proteins genetics, Hep G2 Cells, Hepatitis C, Chronic metabolism, Hepatitis C, Chronic virology, Humans, Mice, Mice, Inbred BALB C, Mice, Transgenic, Nerve Tissue Proteins immunology, Oligonucleotide Array Sequence Analysis, Oxidoreductases Acting on CH-CH Group Donors immunology, RNA chemistry, RNA genetics, RNA Interference, Reverse Transcriptase Polymerase Chain Reaction, Antibodies, Monoclonal therapeutic use, Carrier Proteins metabolism, GABA Plasma Membrane Transport Proteins metabolism, Hepacivirus physiology, Hepatitis C, Chronic drug therapy, Virus Replication drug effects
- Abstract
Background: We recently established a monoclonal antibody (2-152a MAb) that binds to 3β-hydroxysterol-Δ24-reductase (DHCR24) by immunizing mice with cells (RzM6-LC) persistently expressing hepatitis C virus (HCV). Here, we aimed to analyze the activity of 2-152a MAb against HCV replication and explore the molecular mechanism underlying the antiviral activity., Methods: We characterized the effects of 2-152a MAb on HCV replication and performed a microarray analysis of antibody-treated HCV replicon cells. The molecules showing a significant change after the antibody treatment were screened to examine their relationship with HCV replication., Results: The antibody had antiviral activity both in vitro and in vivo (chimeric mice). In the microarray analysis, 2-152a MAb significantly suppressed the expression of betaine/GABA transporter-1 (BGT-1) in 2 HCV replicon cell lines but not in HCV-cured cells. Silencing of BGT-1 expression by small interfering RNA (siRNA) revealed significant suppression of HCV replication and infection without cytotoxicity. Further, BGT-1 expression was significantly increased in the presence of HCV (P < .05)., Conclusions: Our results suggest that 2-152a MAb suppresses HCV replication and infection through BGT-1. These findings highlight important roles of BGT-1 in HCV replication and reveal a possible target for anti-HCV therapy.
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- 2011
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31. Crucial role of c-Myc in the generation of induced pluripotent stem cells.
- Author
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Araki R, Hoki Y, Uda M, Nakamura M, Jincho Y, Tamura C, Sunayama M, Ando S, Sugiura M, Yoshida MA, Kasama Y, and Abe M
- Subjects
- Animals, Blastomeres physiology, Chimera, Embryonic Stem Cells cytology, Embryonic Stem Cells physiology, Female, Genes, myc, Induced Pluripotent Stem Cells cytology, Induced Pluripotent Stem Cells metabolism, Male, Mice, Mice, Inbred C57BL, Pregnancy, Proto-Oncogene Proteins c-myc biosynthesis, Transduction, Genetic, Induced Pluripotent Stem Cells physiology, Proto-Oncogene Proteins c-myc genetics
- Abstract
c-Myc transduction has been considered previously to be nonessential for induced pluripotent stem cell (iPSC) generation. In this study, we investigated the effects of c-Myc transduction on the generation of iPSCs from an inbred mouse strain using a genome integration-free vector to exclude the effects of the genetic background and the genomic integration of exogenous genes. Our findings reveal a clear difference between iPSCs generated using the four defined factors including c-Myc (4F-iPSCs) and those produced without c-Myc (3F-iPSCs). Molecular and cellular analyses did not reveal any differences between 3F-iPSCs and 4F-iPSCs, as reported previously. However, a chimeric mice formation test indicated clear differences, whereby few highly chimeric mice and no germline transmission was observed using 3F-iPSCs. Similar differences were also observed in the mouse line that has been widely used in iPSC studies. Furthermore, the defect in 3F-iPSCs was considerably improved by trichostatin A, a histone deacetyl transferase inhibitor, indicating that c-Myc plays a crucial role in iPSC generation through the control of histone acetylation. Indeed, low levels of histone acetylation were observed in 3F-iPSCs. Our results shed new light on iPSC generation mechanisms and strongly recommend c-Myc transduction for preparing high-quality iPSCs., (Copyright © 2011 AlphaMed Press.)
- Published
- 2011
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32. Translocase of outer mitochondrial membrane 70 expression is induced by hepatitis C virus and is related to the apoptotic response.
- Author
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Takano T, Kohara M, Kasama Y, Nishimura T, Saito M, Kai C, and Tsukiyama-Kohara K
- Subjects
- Cell Line, Hepatitis C pathology, Hepatitis C virology, Hepatocytes pathology, Humans, Intracellular Signaling Peptides and Proteins, Mitochondrial Precursor Protein Import Complex Proteins, Apoptosis, Carrier Proteins metabolism, Hepacivirus pathogenicity, Hepatocytes virology, Mitochondrial Membrane Transport Proteins biosynthesis, Mitochondrial Membranes enzymology, Viral Nonstructural Proteins metabolism
- Abstract
The localization of hepatitis C virus (HCV) proteins in cells leads to several problems. The translocase of outer mitochondrial membrane 70 (TOM70) is a mitochondrial import receptor. In this study, TOM70 expression was induced by HCV infection. TOM70 overexpression induced resistance to tumor necrosis factor-alpha (TNF-α)-mediated apoptosis but not to Fas-induced apoptosis in HepG2 cells. TOM70 was found to be induced by the HCV non-structural protein (NS)3/4A protein, and silencing of TOM70 decreased the levels of the NS3 and Mcl-1 proteins. These results indicate that TOM70 can directly interact with the NS3 protein. In hepatoma cells, silencing of TOM70 induced apoptosis and increased caspase-3/7 activity but did not modify caspase-8 and caspase-9 activity. TOM70 silencing-induced apoptosis was impaired in HCV NS3/4A protein-expressing cells. Thus, this study revealed a novel finding, that is, TOM70 is linked with the NS3 protein and the apoptotic response., (Copyright © 2011 Wiley-Liss, Inc.)
- Published
- 2011
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33. Hepatitis C virus-related lymphomagenesis in a mouse model.
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Tsukiyama-Kohara K, Sekiguchi S, Kasama Y, Salem NE, Machida K, and Kohara M
- Abstract
B cell non-Hodgkin lymphoma is a typical extrahepatic manifestation frequently associated with hepatitis C virus (HCV) infection. The mechanism by which HCV infection leads to lymphoproliferative disorder remains unclear. Our group established HCV transgenic mice that expressed the full HCV genome in B cells (RzCD19Cre mice). We observed a 25.0% incidence of diffuse large B cell non-Hodgkin lymphomas (22.2% in male and 29.6% in female mice) within 600 days of birth. Interestingly, RzCD19Cre mice with substantially elevated serum-soluble interleukin-2 receptor α-subunit (sIL-2Rα) levels (>1000 pg/mL) developed B cell lymphomas. Another mouse model of lymphoproliferative disorder was established by persistent expression of HCV structural proteins through disruption of interferon regulatory factor-1 (irf-1(_/_)/CN2 mice). Irf-1(_/_)/CN2 mice showed extremely high incidences of lymphomas and lymphoproliferative disorders. Moreover, these mice showed increased levels of interleukin (IL)-2, IL-10, and Bcl-2 as well as increased Bcl-2 expression, which promoted oncogenic transformation of lymphocytes.
- Published
- 2011
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34. Persistent expression of the full genome of hepatitis C virus in B cells induces spontaneous development of B-cell lymphomas in vivo.
- Author
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Kasama Y, Sekiguchi S, Saito M, Tanaka K, Satoh M, Kuwahara K, Sakaguchi N, Takeya M, Hiasa Y, Kohara M, and Tsukiyama-Kohara K
- Subjects
- Animals, Cell Transformation, Viral genetics, Disease Models, Animal, Enzyme-Linked Immunosorbent Assay, Female, Genes, Viral, Immunohistochemistry, Interleukin-2 Receptor alpha Subunit biosynthesis, Lymphoma, Large B-Cell, Diffuse pathology, Male, Mice, Mice, Transgenic, RNA, Messenger analysis, Reverse Transcriptase Polymerase Chain Reaction, Cell Transformation, Neoplastic genetics, Hepacivirus genetics, Lymphoma, Large B-Cell, Diffuse virology
- Abstract
Extrahepatic manifestations of hepatitis C virus (HCV) infection occur in 40%-70% of HCV-infected patients. B-cell non-Hodgkin lymphoma is a typical extrahepatic manifestation frequently associated with HCV infection. The mechanism by which HCV infection of B cells leads to lymphoma remains unclear. Here we established HCV transgenic mice that express the full HCV genome in B cells (RzCD19Cre mice) and observed a 25.0% incidence of diffuse large B-cell non-Hodgkin lymphomas (22.2% in males and 29.6% in females) within 600 days after birth. Expression levels of aspartate aminotransferase and alanine aminotransferase, as well as 32 different cytokines, chemokines and growth factors, were examined. The incidence of B-cell lymphoma was significantly correlated with only the level of soluble interleukin-2 receptor α subunit (sIL-2Rα) in RzCD19Cre mouse serum. All RzCD19Cre mice with substantially elevated serum sIL-2Rα levels (> 1000 pg/mL) developed B-cell lymphomas. Moreover, compared with tissues from control animals, the B-cell lymphoma tissues of RzCD19Cre mice expressed significantly higher levels of IL-2Rα. We show that the expression of HCV in B cells promotes non-Hodgkin-type diffuse B-cell lymphoma, and therefore, the RzCD19Cre mouse is a powerful model to study the mechanisms related to the development of HCV-associated B-cell lymphoma.
- Published
- 2010
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35. Generation of genome integration-free induced pluripotent stem cells from fibroblasts of C57BL/6 mice without c-Myc transduction.
- Author
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Jincho Y, Araki R, Hoki Y, Tamura C, Nakamura M, Ando S, Kasama Y, and Abe M
- Subjects
- Animals, Cell Culture Techniques, Clone Cells cytology, Embryonic Stem Cells cytology, Methods, Mice, Species Specificity, Transduction, Genetic, Fibroblasts cytology, Induced Pluripotent Stem Cells cytology, Proto-Oncogene Proteins c-myc pharmacology
- Abstract
Although the induction of genome integration-free induced pluripotent stem cells (iPSCs) has been reported, c-Myc was still required for the efficient generation of these cells. Herein, we report mouse strain-dependent differences in the c-Myc dependence for iPSC generation and the successful generation of genome integration-free iPSCs without c-Myc transduction using C57BL/6 mouse embryonic fibroblasts. We performed 49 independent experiments and obtained a total of 24 iPSC clones, including 18 genome integration-free iPSC clones. These iPSCs were indistinguishable from embryonic stem cells and from iPSCs generated using other methods. Furthermore, the generation of three-factor iPSCs free of virus vectors revealed the contribution of c-Myc to the genomic integration of external genes. C57BL/6 is an inbred mouse strain with substantial advantages for use in genetic and molecular biological studies due to its use in the whole mouse genome sequencing project. Thus, the present series of C57BL/6 iPSCs generated by various procedures will serve as a valuable resource for future genetic studies of iPSC generation.
- Published
- 2010
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36. A layered ionic crystal of polar Li@C(60) superatoms.
- Author
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Aoyagi S, Nishibori E, Sawa H, Sugimoto K, Takata M, Miyata Y, Kitaura R, Shinohara H, Okada H, Sakai T, Ono Y, Kawachi K, Yokoo K, Ono S, Omote K, Kasama Y, Ishikawa S, Komuro T, and Tobita H
- Subjects
- Antimony chemistry, Crystallography, X-Ray, Magnetic Resonance Spectroscopy, Molecular Conformation, Fullerenes chemistry, Lithium chemistry
- Abstract
If the physical properties of C(60) fullerene molecules can be controlled in C(60) products already in use in various applications, the potential for industrial development will be significant. Encapsulation of a metal atom in the C(60) fullerene molecule is a promising way to control its physical properties. However, the isolation of C(60)-based metallofullerenes has been difficult due to their insolubility. Here, we report the complete isolation and determination of the molecular and crystal structure of polar cationic Li@C(60) metallofullerene. The physical and chemical properties of Li@C(60) cation are compared with those of pristine C(60). It is found that the lithium cation is located at off-centre positions in the C(60)-I(h) cage interior and that the [Li(+)@C(60)] salt has a unique two-dimensional structure. The present method of purification and crystallization of C(60)-based metallofullerenes provides a new C(60) fullerene material that contains a metal atom.
- Published
- 2010
- Full Text
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37. Conversion of ancestral fibroblasts to induced pluripotent stem cells.
- Author
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Araki R, Jincho Y, Hoki Y, Nakamura M, Tamura C, Ando S, Kasama Y, and Abe M
- Subjects
- Animals, Cells, Cultured, Fibroblasts metabolism, Induced Pluripotent Stem Cells metabolism, Mice, Reverse Transcriptase Polymerase Chain Reaction, Fibroblasts cytology, Induced Pluripotent Stem Cells cytology
- Abstract
The emergence of induced pluripotent stem cells (iPSCs) from an ancestral somatic cell is one of the most important processes underlying their generation, but the mechanism has yet to be identified. This is principally because these cells emerge at a low frequency, about 0.1% in the case of fibroblasts, and in a stochastic manner. In our current study, we succeeded in identifying ancestral fibroblasts and the subsequent processes leading to their conversion to iPSCs. The ancestral fibroblasts were found to divide several times in a morphologically symmetric manner, maintaining a fibroblastic shape, and then gradually transform into embryonic stem-like cells. Interestingly, this conversion occurred within 48 hours after gene introduction in most iPSC generations. This is the first report to directly observe a cell lineage conversion of somatic cells to stem cells and provides a critical new insight into the "black box" of iPSCs, that is, the first three days of their generation.
- Published
- 2010
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38. Hepatitis C virus impairs p53 via persistent overexpression of 3beta-hydroxysterol Delta24-reductase.
- Author
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Nishimura T, Kohara M, Izumi K, Kasama Y, Hirata Y, Huang Y, Shuda M, Mukaidani C, Takano T, Tokunaga Y, Nuriya H, Satoh M, Saito M, Kai C, and Tsukiyama-Kohara K
- Subjects
- Acetylation drug effects, Animals, Apoptosis drug effects, Apoptosis genetics, Cell Nucleus genetics, Cell Nucleus metabolism, Cytoplasm genetics, Cytoplasm metabolism, Enzyme Induction genetics, Genome-Wide Association Study, Hep G2 Cells, Hepatitis C genetics, Humans, Hydrogen Peroxide pharmacology, Mice, Mice, Inbred BALB C, Mice, Nude, Nerve Tissue Proteins genetics, Oxidants pharmacology, Oxidative Stress drug effects, Oxidative Stress genetics, Oxidoreductases Acting on CH-CH Group Donors genetics, Phosphorylation drug effects, Phosphorylation genetics, Proto-Oncogene Proteins c-mdm2 genetics, Proto-Oncogene Proteins c-mdm2 metabolism, Tumor Suppressor Protein p53 genetics, Cell Transformation, Viral, Hepacivirus, Hepatitis C metabolism, Hepatocytes metabolism, Nerve Tissue Proteins biosynthesis, Oxidoreductases Acting on CH-CH Group Donors biosynthesis, Tumor Suppressor Protein p53 metabolism
- Abstract
Persistent infection with hepatitis C virus (HCV) induces tumorigenicity in hepatocytes. To gain insight into the mechanisms underlying this process, we generated monoclonal antibodies on a genome-wide scale against an HCV-expressing human hepatoblastoma-derived cell line, RzM6-LC, showing augmented tumorigenicity. We identified 3beta-hydroxysterol Delta24-reductase (DHCR24) from this screen and showed that its expression reflected tumorigenicity. HCV induced the DHCR24 overexpression in human hepatocytes. Ectopic or HCV-induced DHCR24 overexpression resulted in resistance to oxidative stress-induced apoptosis and suppressed p53 activity. DHCR24 overexpression in these cells paralleled the increased interaction between p53 and MDM2 (also known as HDM2), a p53-specific E3 ubiquitin ligase, in the cytoplasm. Persistent DHCR24 overexpression did not alter the phosphorylation status of p53 but resulted in decreased acetylation of p53 at lysine residues 373 and 382 in the nucleus after treatment with hydrogen peroxide. Taken together, these results suggest that DHCR24 is elevated in response to HCV infection and inhibits the p53 stress response by stimulating the accumulation of the MDM2-p53 complex in the cytoplasm and by inhibiting the acetylation of p53 in the nucleus.
- Published
- 2009
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39. Hepatitis C virus and disrupted interferon signaling promote lymphoproliferation via type II CD95 and interleukins.
- Author
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Machida K, Tsukiyama-Kohara K, Sekiguch S, Seike E, Tóne S, Hayashi Y, Tobita Y, Kasama Y, Shimizu M, Takahashi H, Taya C, Yonekawa H, Tanaka N, and Kohara M
- Subjects
- Age Factors, Animals, Apoptosis, B-Lymphocytes immunology, B-Lymphocytes virology, Caspases metabolism, Cell Proliferation, Disease Models, Animal, Female, Hepacivirus genetics, Hepatitis C, Chronic immunology, Hepatitis C, Chronic pathology, Interferon Regulatory Factor-1 deficiency, Interferon Regulatory Factor-1 genetics, Interferon Regulatory Factor-1 metabolism, Interleukin-10 metabolism, Interleukin-12 metabolism, Interleukin-2 metabolism, Lymphoma immunology, Lymphoma virology, Lymphoproliferative Disorders pathology, Male, Mice, Mice, Knockout, Mice, Transgenic, Proto-Oncogene Proteins c-bcl-2 metabolism, Spleen immunology, Spleen virology, T-Lymphocytes immunology, T-Lymphocytes virology, Time Factors, Viral Core Proteins metabolism, Viral Envelope Proteins metabolism, Viral Nonstructural Proteins metabolism, Viral Proteins genetics, Hepacivirus metabolism, Hepatitis C, Chronic complications, Interleukins metabolism, Lymphoproliferative Disorders immunology, Lymphoproliferative Disorders virology, Signal Transduction, Viral Proteins metabolism, fas Receptor metabolism
- Abstract
Background & Aims: The molecular mechanisms of lymphoproliferation associated with the disruption of interferon (IFN) signaling and chronic hepatitis C virus (HCV) infection are poorly understood. Lymphomas are extrahepatic manifestations of HCV infection; we sought to clarify the molecular mechanisms of these processes., Methods: We established interferon regulatory factor-1-null (irf-1(-/-)) mice with inducible and persistent expression of HCV structural proteins (irf-1/CN2 mice). All the mice (n = 900) were observed for at least 600 days after Cre/loxP switching. Histologic analyses, as well as analyses of lymphoproliferation, sensitivity to Fas-induced apoptosis, colony formation, and cytokine production, were performed. Proteins associated with these processes were also assessed., Results: Irf-1/CN2 mice had extremely high incidences of lymphomas and lymphoproliferative disorders and displayed increased mortality. Disruption of irf-1 reduced the sensitivity to Fas-induced apoptosis and decreased the levels of caspases-3/7 and caspase-9 messenger RNA species and enzymatic activities. Furthermore, the irf-1/CN2 mice showed decreased activation of caspases-3/7 and caspase-9 and increased levels of interleukin (IL)-2, IL-10, and Bcl-2, as well as increased Bcl-2 expression, which promoted oncogenic transformation of lymphocytes. IL-2 and IL-10 were induced by the HCV core protein in splenocytes., Conclusions: Disruption of IFN signaling resulted in development of lymphoma, indicating that differential signaling occurs in lymphocytes compared with liver. This mouse model, in which HCV expression and disruption of IFN signaling synergize to promote lymphoproliferation, will be an important tool for the development of therapeutic agents that target the lymphoproliferative pathway.
- Published
- 2009
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40. Epidemic of human parechovirus type 3 in Hiroshima city, Japan in 2008.
- Author
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Yamamoto M, Abe K, Kuniyori K, Kunii E, Ito F, Kasama Y, Yoshioka Y, and Noda M
- Subjects
- Humans, Infant, Infant, Newborn, Japan epidemiology, Parechovirus isolation & purification, Phylogeny, Picornaviridae Infections diagnosis, Disease Outbreaks, Picornaviridae Infections epidemiology
- Published
- 2009
41. Cloning of the pactamycin biosynthetic gene cluster and characterization of a crucial glycosyltransferase prior to a unique cyclopentane ring formation.
- Author
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Kudo F, Kasama Y, Hirayama T, and Eguchi T
- Subjects
- Bacterial Proteins metabolism, Cyclopentanes chemistry, Glucosides metabolism, Glycosylation, Open Reading Frames physiology, Pactamycin chemistry, Salicylates metabolism, Streptomyces metabolism, Bacterial Proteins genetics, Cyclopentanes metabolism, Genes, Bacterial genetics, Glycosyltransferases genetics, Glycosyltransferases metabolism, Multigene Family, Pactamycin biosynthesis, Streptomyces genetics
- Abstract
The biosynthetic gene (pct) cluster for an antitumor antibiotic pactamycin was identified by use of a gene for putative radical S-adenosylmethionine methyltransferase as a probe. The pct gene cluster is localized to a 34 kb contiguous DNA from Streptomyces pactum NBRC 13433 and contains 24 open reading frames. Based on the bioinformatic analysis, a plausible biosynthetic pathway for pactamycin comprising of a unique cyclopentane ring, 3-aminoacetophenone, and 6-methylsalicylate was proposed. The pctL gene encoding a glycosyltransferase was speculated to be involved in an N-glycoside formation between 3-aminoacetophenone and UDP-N-acetyl-alpha-D-glucosamine prior to a unique cyclopentane ring formation. The pctL gene was then heterologously expressed in Escherichia coli and the enzymatic activity of the recombinant PctL protein was investigated. Consequently, the PctL protein was found to catalyze the expected reaction forming beta-N-glycoside. The enzymatic activity of the PctL protein clearly confirmed that the present identified gene cluster is for the biosynthesis of pactamycin. Also, a glycosylation prior to cyclopentane ring formation was proposed to be a general strategy in the biosynthesis of the structurally related cyclopentane containing compounds.
- Published
- 2007
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42. Overlapping of genes in the human genome.
- Author
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Nakayama T, Asai S, Takahashi Y, Maekawa O, and Kasama Y
- Abstract
Overlapping genes are relatively common in DNA and RNA viruses. There are several examples in bacterial and eukaryotic genomes, but, in general, overlapping genes are quite rare in organisms other than viruses. There have been a few reports of overlapping genes in mammalian genomes. The present study identified all of the overlapping loci and overlapping exons in every chromosome of the human genome using a public database. The total number of overlapping loci on the same and opposite strands was 949 and 743, respectively. Similarly, in every chromosome, the instances in which two loci were located on the same strand was similar to the number of 2 genes observed on opposite strands, except for chromosome 5. The number of 2 exons located on the same strand was higher than that for 2 exons located on opposite strands, indicating the presence of many comprehensive-type overlaps. The mean percentage of overlapping exons on opposite strands in each chromosome was 3.3%, suggesting that parts of the nucleotide sequences of 26,501 exons are used to produce 2 transcribed products from each strand. The ratio of the number of overlapping regions to chromosomal length revealed that, on chromosomes 22, 17 and 19, ratios were high for both types of 2 loci, with exons located on the same and opposite strands. Ratios were low on chromosomes Y, 13 and 18. These results show that all overlapping types are distributed throughout the human genome, but that distributions differ for each chromosome.
- Published
- 2007
43. Genetic characterization of multidrug resistance in Shigella spp. from Japan.
- Author
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Ahmed AM, Furuta K, Shimomura K, Kasama Y, and Shimamoto T
- Subjects
- Anti-Infective Agents pharmacology, DNA, Bacterial, Drug Resistance, Multiple, Bacterial genetics, Electrophoresis, Gel, Pulsed-Field, Genes, Bacterial, Humans, Integrons genetics, Japan, Molecular Sequence Data, Sequence Analysis, Shigella drug effects, beta-Lactamases genetics, Dysentery, Bacillary microbiology, Shigella genetics
- Abstract
This study characterized the genetic basis of antimicrobial resistance of a number of Shigella spp. isolated from humans from 2000 to 2004 in Hiroshima prefecture, Japan. A total of 26 isolates of Shigella spp. were included in this study. Antimicrobial susceptibility tests revealed high levels of resistance, especially to ampicillin, streptomycin, trimethoprim, tetracycline, nalidixic acid and ciprofloxacin. PCR and DNA sequencing were used for screening and characterization of antibiotic-resistance determinants. PCR sequencing analysis revealed the presence of only one type of class 1 integron in one isolate of Shigella sonnei. This class 1 integron was 1904 bp and contained two gene cassettes: a probable esterase/lipase (estX) and aadA1, which confers resistance to streptomycin and spectinomycin. Two types of class 2 integron were identified in this study. One was the classic type (2158 bp) and carried the three conserved resistance gene cassettes of the class 2 integron, dfrA1, sat1 and aadA1, which confer resistance to trimethoprim, streptothricin and streptomycin/spectinomycin, respectively. This type was detected in both Shigella sonnei (14 isolates) and Shigella flexneri (five isolates). The other type was shorter (1313 bp) and carried only two gene cassettes, dfrA1 and sat1. This integron was detected in a single isolate of Shigella sonnei. PFGE patterns showed limited diversity within clusters of the same species. Furthermore, an extended-spectrum beta-lactamase gene, bla(OXA-30), which confers resistance to ampicillin, was characterized in all isolates of Shigella flexneri except the oldest strain, which was isolated in 2000. Southern blot hybridization and conjugation experiments showed that bla(OXA-30) was located in the chromosome.
- Published
- 2006
- Full Text
- View/download PDF
44. More than 40,000 transcripts, including novel and noncoding transcripts, in mouse embryonic stem cells.
- Author
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Araki R, Fukumura R, Sasaki N, Kasama Y, Suzuki N, Takahashi H, Tabata Y, Saito T, and Abe M
- Subjects
- Animals, Cell Differentiation genetics, Cell Line, Cell Lineage genetics, Databases, Genetic, Mice, RNA, Messenger metabolism, RNA, Untranslated metabolism, Reproducibility of Results, Reverse Transcriptase Polymerase Chain Reaction, Embryonic Stem Cells metabolism, Gene Expression Profiling methods, Gene Expression Regulation, Developmental, Transcription, Genetic
- Abstract
To study the transcriptome of embryonic stem cells, we used a new gene expression profiling method that can measure the expression levels of unknown and rarely expressed transcripts precisely. We detected a total of 33,136 signal peaks representing transcripts in mouse embryonic stem cells, E14. Subsequent random cloning of the peaks suggests that mouse embryonic stem cells express at least 40,000 transcripts, of which about 2,000 are still unknown. In addition, we identified 1,022 noncoding transcripts, several of which change depending on differentiation in gene expression. Our database provides a high-resolution expression profile of E14 cells and is applicable to other mouse embryonic stem cell analyses. It includes most transcription regulation factor-encoding genes and a significant number of unknown and noncoding transcripts.
- Published
- 2006
- Full Text
- View/download PDF
45. Podocyte-derived vascular endothelial growth factor mediates the stimulation of alpha3(IV) collagen production by transforming growth factor-beta1 in mouse podocytes.
- Author
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Chen S, Kasama Y, Lee JS, Jim B, Marin M, and Ziyadeh FN
- Subjects
- Animals, Autoantigens drug effects, Autoantigens genetics, Base Sequence, Cell Differentiation, Collagen Type IV drug effects, Collagen Type IV genetics, DNA Primers, Mice, Molecular Sequence Data, Recombinant Proteins pharmacology, Reverse Transcriptase Polymerase Chain Reaction, Signal Transduction drug effects, Signal Transduction physiology, Transforming Growth Factor beta1, Vascular Endothelial Growth Factor A physiology, Vascular Endothelial Growth Factor Receptor-1 genetics, Vascular Endothelial Growth Factor Receptor-1 physiology, Autoantigens biosynthesis, Collagen Type IV biosynthesis, Epithelial Cells physiology, Transforming Growth Factor beta pharmacology, Vascular Endothelial Growth Factor A pharmacology
- Abstract
Podocyte-derived vascular endothelial growth factor (VEGF) is upregulated in diabetes and may contribute to albuminuria. Although believed to act upon the glomerular endothelium, VEGF may have pronounced effects on the podocyte itself. The functionality of this VEGF autocrine loop was investigated in conditionally immortalized mouse podocytes. Exogenous VEGF(164) increased the production of alpha3(IV) collagen, an integral component of the glomerular basement membrane (GBM); this effect was completely prevented by SU5416, a pan-VEGF receptor inhibitor. The VEGF inhibitor also partially prevented the stimulation of alpha3(IV) collagen by transforming growth factor (TGF)-beta1, establishing a novel role for endogenous VEGF. However, VEGF did not influence the production of another novel chain of collagen IV, alpha5(IV) collagen, and SU5416 failed to reverse the known inhibitory effect of TGF-beta1 on alpha5(IV) collagen production. Cultured mouse podocytes possess at least the VEGFR-1 receptor, confirmed by RT-PCR, immunoblotting, and immunocytochemistry. By these techniques, however, VEGFR-2 is absent. VEGF signaling proceeds via autophosphorylation of VEGFR-1 and activation of the phosphatidylinositol 3-kinase (PI3K) pathway. Thus, podocyte-derived VEGF operates in an autocrine loop, likely through VEGFR-1 and PI3K, to stimulate alpha3(IV) collagen production. The TGF-beta1-stimulated endogenous VEGF may have significant implications for podocyte dysfunction in diabetic glomerulopathy, manifesting as GBM thickening and altered macromolecular permeability.
- Published
- 2004
- Full Text
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46. Cultured tubule cells from TGF-beta1 null mice exhibit impaired hypertrophy and fibronectin expression in high glucose.
- Author
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Chen S, Hoffman BB, Lee JS, Kasama Y, Jim B, Kopp JB, and Ziyadeh FN
- Subjects
- Activin Receptors, Type I genetics, Activin Receptors, Type I metabolism, Animals, Cell Division drug effects, Cells, Cultured, Dose-Response Relationship, Drug, Gene Expression drug effects, Hypertrophy, Mice, Mice, Knockout, Protein Serine-Threonine Kinases, Receptor, Transforming Growth Factor-beta Type I, Receptor, Transforming Growth Factor-beta Type II, Receptors, Transforming Growth Factor beta genetics, Receptors, Transforming Growth Factor beta metabolism, Transforming Growth Factor beta metabolism, Transforming Growth Factor beta pharmacology, Transforming Growth Factor beta1, Transforming Growth Factor beta2, Transforming Growth Factor beta3, Fibronectins metabolism, Glucose administration & dosage, Kidney Tubules metabolism, Kidney Tubules pathology, Transforming Growth Factor beta deficiency
- Abstract
Background: To firmly establish the role of the transforming growth factor-beta1 (TGF-beta1) isoform in the pathophysiology of diabetic tubulointerstitial hypertrophy and fibrosis, we examined how the total absence of TGF-beta1 would alter the effect of high glucose on cellular hypertrophy and matrix expression in tubuloepithelial cells cultured from TGF-beta1 null mice., Methods: Primary tubule cell cultures, obtained from kidneys of TGF-beta1 knockout mice and their wild-type littermates, were treated with exogenous TGF-beta1 or high glucose. The TGF-beta system was characterized at the ligand and receptor levels using Northern and Western blotting. Cellular hypertrophy and growth were assessed by thymidine incorporation, cell counting, leucine incorporation, and protein content. Fibronectin expression was assessed by Northern analysis and enzyme-linked immunosorbent assay (ELISA)., Results: Knockout cells did not express TGF-beta1 but did express TGF-beta2, TGF-beta3, and TGF-beta type I and type II receptors. Exogenous TGF-beta1 down-regulated the ligand-binding type II receptor but up-regulated type I receptor expression. Knockout cells proliferated more rapidly than wild-type cells, but restoring TGF-beta1 to knockout cells slowed their proliferation. In wild-type cells, high glucose caused cellular hypertrophy, evidenced by greater leucine incorporation and protein content along with decreased thymidine incorporation. High glucose also increased fibronectin message and protein. However, in knockout cells, high glucose failed to induce hypertrophy and was severely limited in its capacity to stimulate fibronectin., Conclusion: In tubular epithelial cells, TGF-beta1 mediates the hypertrophic and fibronectin-stimulatory effects of high glucose, confirming the role of the TGF-beta1 isoform in the pathogenesis of diabetic tubular hypertrophy and fibronectin overexpression.
- Published
- 2004
- Full Text
- View/download PDF
47. Sequence analysis of 193.4 and 83.9 kbp of mouse and chicken genomic DNAs containing the entire Prkdc (DNA-PKcs) gene.
- Author
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Fujimori A, Hashimoto H, Araki R, Saito T, Sato S, Kasama Y, Tsutsumi Y, Mori M, Fukumura R, Ohhata T, Tatsumi K, and Abe M
- Subjects
- Animals, Base Sequence, Chickens, Conserved Sequence, DNA, DNA-Activated Protein Kinase, Exons, Introns, Mice, Molecular Sequence Data, Nuclear Proteins, Sequence Homology, Nucleic Acid, Species Specificity, DNA-Binding Proteins, Protein Serine-Threonine Kinases genetics
- Abstract
The catalytic subunit of DNA-dependent protein kinase plays critical roles in nonhomologous end joining in repair of DNA double-strand breaks and V(D)J recombination. In addition to the SCID phenotype, it has been suggested that the molecule contributes to the polymorphic variations in radiosensitivity and susceptibility to cancer in mouse strains. Here we show the nucleotide sequence of approximately 193-kbp and 84-kbp genomic regions encoding the entire Prkdc gene (also known as DNA-PKcs) in the mouse and chicken, respectively. A large retroposon was found in intron 51 in the mouse but not in the human or chicken. Comparative analyses of the genome strongly suggested that the region contains only two genes for Prkdc and Mcm4; however, several conserved sequences and cis elements were also predicted.
- Published
- 2002
- Full Text
- View/download PDF
48. Purification and characterization of thermostable beta-N-acetylhexosaminidase of Bacillus stearothermophilus CH-4 isolated from chitin-containing compost.
- Author
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Sakai K, Narihara M, Kasama Y, Wakayama M, and Moriguchi M
- Subjects
- Amino Acid Sequence, Chitinases isolation & purification, Chitinases metabolism, Kinetics, Molecular Sequence Data, Molecular Weight, Sequence Analysis, Substrate Specificity, Waste Products, beta-N-Acetylhexosaminidases chemistry, beta-N-Acetylhexosaminidases isolation & purification, Geobacillus stearothermophilus enzymology, beta-N-Acetylhexosaminidases metabolism
- Abstract
Thermostable exochitinase was purified to homogeneity from the culture fluid of Bacillus stearothermophilus CH-4, which was isolated from agricultural compost containing shrimp and crabs. The enzyme was a single polypeptide with a molecular mass of 74 kDa, and the N-terminal amino acid sequence was WDKVGVTDLI ISLNIPEADAVVVGMTLQLQALHLY. The enzyme specifically hydrolyzed C-4 beta-anomeric bonding of N-acetylchitooligosaccharides, as well as their p-nitrophenyl (pNP) derivatives. The enzyme also hydrolyzed pNP-beta-N-acetyl-D-galactosaminide (26% of the activity of pNP-beta-N-acetyl-D-glucosaminide). These results indicated that the enzyme is a beta-N-acetylhexosaminidase (EC 3.2.1.52). Kms for acetylchitooligosaccharides were 1 x 10(-4) to 6 x 10(-4) M, while those for the pNP derivatives were 4 x 10(-3) to 8 x 10(-3) M. The optimum temperature of the enzyme was 75 degrees C, and it retained 100 and 28% reactivity after heating at 60 and 80 degrees C, respectively. The enzyme exhibited 15 to 20% activity in a reaction mixture containing 80% organic solvents and maintained 91% of its original activity after exposure to 8 M urea. The optimum and stable pH was around 6.5. Fe2+, Zn2+, and Ca2+ activated the enzyme, but Hg2+ was inhibitory. N-Acetyl-D-glucosamine inhibited the enzyme competitively (Ki = 4.3 x 10(-4) M), whereas N-acetyl-D-galactosamine did not; in contrast, D-glucosamine and D-galactosamine activated it.
- Published
- 1994
- Full Text
- View/download PDF
49. STUDIES ON EXPERIMENTAL RICKETS : I. THE OCCURRENCE OF RICKETS IN YOUNG RABBITS BORN OF MOTHERS INFECTED WITH SCHISTOSOMUM JAPONICUM.
- Author
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Kawamura R and Kasama Y
- Abstract
Our observations show that young rabbits born of mothers afflicted with Schistosomum japonicum develop typical rickets. Rickets can also be produced if we infect the young, healthy rabbits with the same parasite. It is natural to suppose that the rachitic changes are caused by the parasite itself. Since, however, a similar disease can be produced in the offspring, when the mother is fed on egg yolk, the causation is not limited to the action of this parasitic toxin alone. The toxin of Schistosoma may disturb the calcium and phosphorus metabolism of bone in young animals, especially in the period of vigorous growth; that is, 20 to 40 days after birth of the rabbits. Or it may exhaust some element important in the calcium and phosphorus metabolism such as vitamin A or D. The fact that exhaustion of the antirachitic factor in the mother causes rickets in the young, as Grant (1924) showed, and that certain low grade infections can exhaust vitamin B as shown by Wedgewood (1924), is in line with this conception. It may be added here that most investigations on rickets have been carried out on rats and dogs. We have found a simple and excellent way of producing rickets in rabbits by dietary deficiency. Concerning this method, we shall report elsewhere.
- Published
- 1925
- Full Text
- View/download PDF
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