26 research outputs found

    Micro RNAs of Epstein-Barr Virus Promote Cell Cycle Progression and Prevent Apoptosis of Primary Human B Cells

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    Cellular and viral microRNAs (miRNAs) are involved in many different processes of key importance and more than 10,000 miRNAs have been identified so far. In general, relatively little is known about their biological functions in mammalian cells because their phenotypic effects are often mild and many of their targets still await identification. The recent discovery that Epstein-Barr virus (EBV) and other herpesviruses produce their own, barely conserved sets of miRNAs suggests that these viruses usurp the host RNA silencing machinery to their advantage in contrast to the antiviral roles of RNA silencing in plants and insects. We have systematically introduced mutations in EBV's precursor miRNA transcripts to prevent their subsequent processing into mature viral miRNAs. Phenotypic analyses of these mutant derivatives of EBV revealed that the viral miRNAs of the BHRF1 locus inhibit apoptosis and favor cell cycle progression and proliferation during the early phase of infected human primary B cells. Our findings also indicate that EBV's miRNAs are not needed to control the exit from latency. The phenotypes of viral miRNAs uncovered by this genetic analysis indicate that they contribute to EBV-associated cellular transformation rather than regulate viral genes of EBV's lytic phase

    Anti-Tumor Effect against Human Cancer Xenografts by a Fully Human Monoclonal Antibody to a Variant 8-Epitope of CD44R1 Expressed on Cancer Stem Cells

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    BACKGROUND: CD44 is a major cellular receptor for hyaluronic acids. The stem structure of CD44 encoded by ten normal exons can be enlarged by ten variant exons (v1-v10) by alternative splicing. We have succeeded in preparing MV5 fully human IgM and its class-switched GV5 IgG monoclonal antibody (mAb) recognizing the extracellular domain of a CD44R1 isoform that contains the inserted region coded by variant (v8, v9 and v10) exons and is expressed on the surface of various human epithelial cancer cells. METHODS AND PRINCIPAL FINDINGS: We demonstrated the growth inhibition of human cancer xenografts by a GV5 IgG mAb reshaped from an MV5 IgM. The epitope recognized by MV5 and GV5 was identified to a v8-coding region by the analysis of mAb binding to various recombinant CD44 proteins by enzyme-linked immunosorbent assay. GV5 showed preferential reactivity against various malignant human cells versus normal human cells assessed by flow cytometry and immunohistological analysis. When ME180 human uterine cervix carcinoma cells were subcutaneously inoculated to athymic mice with GV5, significant inhibition of tumor formation was observed. Furthermore, intraperitoneal injections of GV5markedly inhibited the growth of visible established tumors from HSC-3 human larynx carcinoma cells that had been subcutaneously transplanted one week before the first treatment with GV5. From in vitro experiments, antibody-dependent cellular cytotoxicity and internalization of CD44R1 seemed to be possible mechanisms for in vivo anti-tumor activity by GV5. CONCLUSIONS: CD44R1 is an excellent molecular target for mAb therapy of cancer, possibly superior to molecules targeted by existing therapeutic mAb, such as Trastuzumab and Cetuximab recognizing human epidermal growth factor receptor family

    A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu

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    Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe3+ to Fe2+ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss

    マウス ミサイボウ ノ ニガミ ジョウホウ デンタツ ケイロ ニ カンスル デンキ セイリガクテキ ケンキュウ

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    京都大学0048新制・課程博士博士(農学)甲第9011号農博第1193号新制||農||822(附属図書館)学位論文||H13||N3530(農学部図書室)UT51-2001-F341京都大学大学院農学研究科応用生命科学専攻(主査)教授 森 友彦, 教授 伏木 亨, 教授 北畠 直文学位規則第4条第1項該当Doctor of Agricultural ScienceKyoto UniversityDA

    Influence of moxibustion on collagen-induced arthritis in mice

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    The influence of moxibustion, a traditional Chinese medical treatment, on type II collagen-induced arthritis (CIA) was examined in DBA/1J mice in vivo. Mice were immunized intradermally twice at the 3-week interval with bovine type II collagen (C Il). The main incidence of arthritis started about on day 30 and lasted to day 60 after the first immunization. Moxibustion with three different regimens, was applied at the acupoint equivalent to GV 4 every other day. Moxibustion, from day 0 to day 30 after the first immunization, suppressed the onset and development of arthritis, as well as anti-collagen antibody level. Treatment with moxibustion, from the day 31 to day 60, also resulted in a significant inhibition of progression of arthritis and production of anti-C II antibody. Thirdly we examined the influence of moxibustion on the established arthritis. Moxibustion given from day 61 to day 120, significantly but mildly decreased the anti-C II antibody level in diseased mice, while the bone erosion and joint destruction were not affected. These results indicate that moxibustion could prevent the incidence and attenuates the development of murine CIA

    The Assembly of EDC4 and Dcp1a into Processing Bodies Is Critical for the Translational Regulation of IL-6

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    <div><p>Macrophages play critical roles in the onset of various diseases and in maintaining homeostasis. There are several functional subsets, of which M1 and M2 macrophages are of particular interest because they are differentially involved in inflammation and its resolution. Here, we investigated the differences in regulatory mechanisms between M1- and M2-polarized macrophages by examining mRNA metabolic machineries such as stress granules (SGs) and processing bodies (P-bodies). Human monocytic leukemia THP-1 cells cultured under M1-polarizing conditions (M1-THPs) had less ability to assemble oxidative-stress-induced SGs than those cultured under M2-polarizing conditions (M2-THPs). In contrast, P-body assembly in response to oxidative stress or TLR4 stimulation was increased in M1-THPs as compared to M2-THPs. These results suggest that mRNA metabolism is controlled differently in M1-THPs and M2-THPs. Interestingly, knocking down EDC4 or Dcp1a, which are components of P-bodies, severely reduced the production of IL-6, but not TNF-α in M1-THPs without decreasing the amount of IL-6 mRNA. This is the first report to demonstrate that the assembly of EDC4 and Dcp1a into P-bodies is critical in the posttranscriptional regulation of IL-6. Thus, improving our understanding of the mechanisms governing mRNA metabolism by examining macrophage subtypes may lead to new therapeutic targets.</p></div

    P-body knockdown affects the expression of IL-6-regulating molecules.

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    <p>THP-1 cells were transfected with a siRNA targeting EDC4 or Dcp1a, or with a non-targeting siRNA (siNeg). Twenty hours after transfection, the cells were differentiated with PMA, followed by activation later. The expression levels of (A) miRNAs and (B) NF-IL6 were determined by quantitative PCR as described in Methods. *p<0.05, **p<0.01, ***p<0.001</p
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