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Ishizaki K, Mizutani M, Shimamura M, Masuda A, Nishihama R, Kohchi T. Essential role of the E3 ubiquitin ligase nopperabo1 in schizogenous intercellular space formation in the liverwort Marchantia polymorpha. THE PLANT CELL 2013; 25:4075-84. [PMID: 24170128 PMCID: PMC3877802 DOI: 10.1105/tpc.113.117051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/25/2013] [Accepted: 10/08/2013] [Indexed: 05/17/2023]
Abstract
The vast majority of land plants develop gas-exchange tissues with intercellular spaces (ICSs) connected directly to the air. Although the developmental processes of ICS have been described in detail at the morphological and ultrastructural level in diverse land plants, little is known about the molecular mechanism responsible for ICS formation. The liverwort Marchantia polymorpha develops a multilayered tissue with a large ICS (air chamber), whose formation is initiated at selected positions of epidermal cells. We isolated a mutant of M. polymorpha showing impaired air-chamber formation, nopperabo1 (nop1), from T-DNA-tagged lines. In nop1 plants, no ICS was formed; consequently, a single-layered epidermis developed on the dorsal side of the thallus. The causal gene NOP1 encodes a Plant U-box (PUB) E3 ubiquitin ligase carrying tandem ARMADILLO (ARM) repeats in the C terminus. An in vitro ubiquitination assay indicated that the NOP1 protein possesses E3 ubiquitin ligase activity in a U-box-dependent manner. Confocal microscopy and biochemical analysis showed that NOP1 was localized to the plasma membrane. Our investigation demonstrated the essential role of the PUB-ARM-type ubiquitin ligase in ICS formation in M. polymorpha, which sheds light on the molecular mechanism of schizogenous ICS formation in land plants.
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Shimamura M, Hidaka H. Therapeutic potential of cholesteryl O-acyl α-glucoside found in Helicobacter pylori. Curr Med Chem 2013; 19:4869-74. [PMID: 22934809 DOI: 10.2174/092986712803341502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 08/13/2012] [Accepted: 08/23/2012] [Indexed: 11/22/2022]
Abstract
Steryl glycosides are derivatives of sterols where the 3β-hydroxy group is glycosylated. Some of them are further converted to steryl O-acyl glycosides. Steryl glycosides and their derivatives are widely distributed in plants, algae, and fungi, but are relatively rarely distributed in bacteria and animals. Accumulating evidence suggests that glycosylation of sterols not only modifies physicochemical properties of cell membranes but also alters immunogenicity of the cells. Helicobacter pylori, that colonizes the stomach and causes gastric diseases, is auxotrophic for cholesterol, so that it extracts this lipid from plasma membranes of epithelial cells of the host stomach. Since incorporation of cholesterol promotes immune responses of the host, Helicobacter pylori converts cholesterol to cholesteryl glucoside (ChG) and then to cholesteryl 6'-O-acyl glucoside (ChAcG) to evade the immune surveillance. We have found that ChAcG thus produced is specifically recognized by invariant Vα14-Jα18 TCR(+) (Vα14) NKT cells in a CD1-dependent manner. We have also found that activation of Vα14 NKT cells by administration of ChAcG retains homeostasis of immunity upon exposure to allergens and reduces the incidence of allergy. In this article, overview of immunological functions of steryl glycosides with an emphasis on the immunoregulatory functions of ChAcG, is demonstrated.
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Nagayama Y, Nakahara M, Shimamura M, Horie I, Arima K, Abiru N. Prophylactic and therapeutic efficacies of a selective inhibitor of the immunoproteasome for Hashimoto's thyroiditis, but not for Graves' hyperthyroidism, in mice. Clin Exp Immunol 2012; 168:268-73. [PMID: 22519588 DOI: 10.1111/j.1365-2249.2012.04578.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Major histocompatibility complex (MHC) class I-restricted T cell epitopes are generated mainly by the immunoproteasome in antigen-presenting cells. Therefore, inhibition of activity of this proteolytic complex molecule is thought to be a potential treatment for cell-mediated autoimmune diseases. We therefore studied the efficacy of an immunoproteasome inhibitor, ONX 0914 (formerly PR-957), for the treatment of autoimmune thyroid diseases, including cell-mediated Hashimoto's thyroiditis and autoantibody-mediated Graves' hyperthyroidism using mouse models. Our data show that ONX 0914 was effective prophylactically and therapeutically at suppressing the degree of intrathyroidal lymphocyte infiltration and, to a lesser degree, the titres of anti-thyroglobulin autoantibodies in non-obese diabetic (NOD)-H2(h4) mice, an iodine-induced autoimmune thyroiditis model. It also inhibited differentiation of T cells to T helper type 1 (Th1) and Th17 cells, effector T cell subsets critical for development of thyroiditis in this mouse strain. In contrast, its effect on the Graves' model was negligible. Although ONX 0914 exerts its immune-suppressive effect through not only suppression of immune proteasome but also other mechanism(s), such as inhibition of T cell differentiation, the present results suggest that the immunoproteasome is a novel drug target in treatment of Hashimoto's thyroiditis in particular and cell-mediated autoimmune diseases in general.
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Shimamura M, Itouga M, Tsubota H. Evolution of apolar sporocytes in marchantialean liverworts: implications from molecular phylogeny. JOURNAL OF PLANT RESEARCH 2012; 125:197-206. [PMID: 21544643 DOI: 10.1007/s10265-011-0425-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 04/03/2011] [Indexed: 05/30/2023]
Abstract
In meiosis of basal land plants, meiotic division planes are typically predicted by quadri-lobing of the cytoplasm and/or quadri-partitioning of plastids prior to nuclear divisions. However, sporocytes of several marchantialean liverworts display no indication of premeiotic establishment of quadripolarity, as is observed in flowering plants. In these cases, the shape of sporocytes remains spherical or elliptical and numerous plastids are distributed randomly in the cytoplasm during meiosis. Through a survey of sporocyte morphology in marchantialean liverworts, we newly report the occurrence of apolar sporocytes in Sauteria japonica and Athalamia nana (Cleveaceae; Marchantiales). Molecular phylogenetic analyses revealed that the quadri-lobing of cytoplasm and quadri-partitioning of plastids were lost independently several times during the evolution of marchantialean liverworts. In addition, our phylogenetic analyses indicate that the simplified sporophytes of several marchantialean liverworts are not a primitive condition but rather represent the result of reductive evolution. The loss of the quadripolarity of sporocytes appears to correlate with the evolutionary trend of the sporophyte towards reductions. Through the evolution of the simplified sporophytes, suppression of mitotic divisions of sporogenous cells might had caused not only the modification of sporophyte ontogeny but also the drastic cytological change of sporocyte.
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Furumoto T, Yamaguchi T, Ohshima-Ichie Y, Nakamura M, Tsuchida-Iwata Y, Shimamura M, Ohnishi J, Hata S, Gowik U, Westhoff P, Bräutigam A, Weber APM, Izui K. A plastidial sodium-dependent pyruvate transporter. Nature 2011; 476:472-5. [DOI: 10.1038/nature10250] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Accepted: 06/01/2011] [Indexed: 11/09/2022]
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Brown RC, Lemmon BE, Shimamura M. Diversity in meiotic spindle origin and determination of cytokinetic planes in sporogenesis of complex thalloid liverworts (Marchantiopsida). JOURNAL OF PLANT RESEARCH 2010; 123:589-605. [PMID: 20039093 DOI: 10.1007/s10265-009-0286-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 11/02/2009] [Indexed: 05/23/2023]
Abstract
As the earliest divergent land plants, bryophytes (mosses, hornworts, and liverworts) provide insight into the evolution of the unique plant process of sporogenesis by which meiosis results in heavy walled spores. New immunohistochemical data on microtubules and gamma-tubulin in four genera of complex thalloid liverworts combined with previously published data on another four genera demonstrate grades in the evolution of spindle organization in meiosis. We have discovered that all recognized forms of microtubule organizing centers (MTOCs) in plant cells (plastid MTOCs, spheroid cytoplasmic MTOCs, polar organizers, and nuclear envelope MTOCs) occur in organization of the meiotic spindle of complex thalloid liverworts. In addition, all aspects of pre-meiotic preparation for quadripartitioning of the sporocyte into a tetrad of spores occur, with the exception of pre-meiotic wall precursors found in certain simple thalloids. The preparation includes morphogenetic plastid migration, cortical bands of microtubules that mark future cytokinetic planes in pre-meiosis, quadrilobing of the cytoplasm during meiotic prophase, and quadripolar microtubule systems that are transformed into functionally bipolar metaphase I spindles. Quadripolar spindle origin is typical of bryophyte sporogenesis even though the MTOCs involved may differ. However, in certain crown taxa of complex thalloids the spindle develops with no traces of quadripolarity and placement of intersporal walls is determined after meiosis, as is typical of higher plants.
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Kajiyama S, Joseph B, Inoue F, Shimamura M, Fukusaki E, Tomizawa K, Kobayashi A. Transient gene expression in guard cell chloroplasts of tobacco using ArF excimer laser microablation. J Biosci Bioeng 2008; 106:194-8. [PMID: 18804064 DOI: 10.1263/jbb.106.194] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Accepted: 05/23/2008] [Indexed: 11/17/2022]
Abstract
In this paper, we report a novel method for delivering genes into chloroplasts of tobacco cells using laser microablation. The plasmid pLD200-GFP was introduced into chloroplasts of Nicotiana tabacum cv. Xanthi guard cells and transient GFP expression was detected in the chloroplasts after 2-3 d of incubation. The technique uses an argon fluoride (ArF) excimer laser to perforate the cell surface in a 4 mum(2) area in the presence of plasmid coated gold microparticles. Pretreatment of guard cells to promote stomatal closure prior to laser ablation resulted in a significant increase in the survival rate of cells and a transient expression rate of 2-3% in trial number basis was archived. Our method has unique advantages such as avoiding laborious pretreatments that adversely affect cell viability and specific delivery of transgenes into a desired cell in complex leaf tissue. This technique is a potential tool for cell specific transient gene expression studies for elucidation of gene regulation and expression.
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Shimamura M. Glycolipid stimulators for NKT cells bearing invariant V alpha 19-J alpha 33 TCR alpha chains. Mini Rev Med Chem 2008; 8:285-9. [PMID: 18336348 DOI: 10.2174/138955708783744119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Attempts have been made to find specific antigens for a novel NKT cell subset bearing invariant V alpha 19-J alpha 33 TCR alpha chains (V alpha 19 NKT cell). Comprehensive examinations revealed substantial antigenic activity in synthetic alpha-mannosylceramide (ManCer) that was presented by MR1. Structural modification of the sphingosine moiety of alpha-ManCer improved antigenic activity to enhance either Th1 or Th2 -promoting cytokine production by V alpha 19 NKT cells. Such alpha-ManCer analogues will be useful for developing new therapies as immunomodulators.
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Shimamura M, Yamaguchi T, Deguchi H. Airborne sperm of Conocephalum conicum (Conocephalaceae). JOURNAL OF PLANT RESEARCH 2008; 121:69-71. [PMID: 18058191 DOI: 10.1007/s10265-007-0128-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Accepted: 10/17/2007] [Indexed: 05/25/2023]
Abstract
We have obtained the first momentary photographs of sperms just as they are discharged from the antheridium of a liverwort, Conocephalum conicum, and have succeeded in monitoring the airborne sperms of bryophytes under field conditions. Airborne sperm of liverworts seems to be an effective strategy for raising the efficiency of fertilization between male and female plants separated in a drought environment.
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Narita M, Shimamura M, Imai S, Kubota C, Yajima Y, Takagi T, Shiokawa M, Inoue T, Suzuki M, Suzuki T. Role of interleukin-1beta and tumor necrosis factor-alpha-dependent expression of cyclooxygenase-2 mRNA in thermal hyperalgesia induced by chronic inflammation in mice. Neuroscience 2007; 152:477-86. [PMID: 18262365 DOI: 10.1016/j.neuroscience.2007.10.039] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 10/17/2007] [Accepted: 10/19/2007] [Indexed: 02/09/2023]
Abstract
The present study investigated whether the endogenous pro-inflammatory cytokines [interleukin (IL)-1beta and tumor necrosis factor-alpha (TNF-alpha)]-dependent expression of cyclooxygenase-2 (COX-2) mRNA within the spinal cord could be involved in the development of chronic inflammatory pain-like behaviors in mice. We demonstrated that the expression of COX-2 mRNA on the ipsilateral side of the spinal cord was significantly increased 6 h and 3 days after intraplantar injection of complete Freund's adjuvant (CFA), compared with the expression in saline-treated mice. In addition, the chronic pain-like behaviors following CFA injection were markedly suppressed by repeated intrathecal (i.t.) pre-treatment with the COX-2 inhibitor etodolac, but not with the COX-1 inhibitor mofezolac. The cytosolic level of the activated form of nuclear factor-kappa B (NF-kappaB), which is a major contributor to the induction of COX-2, on the ipsilateral side of the mouse spinal cord was also increased compared with that in the saline-treated mice. The key finding in the present study was that a single i.t. injection with either IL-1beta or TNF-alpha induced a marked increase in spinal COX-2 mRNA and persistent thermal hyperalgesia in mice. Furthermore, CFA-induced hypersensitivity to inflammatory pain was significantly reduced by repeated i.t. pre-injection of the recombinant Fc chimera of IL-1 receptor I or soluble TNF receptor I, which sequesters endogenous IL-1beta or TNF-alpha, respectively. In contrast, the expression of spinal COX-2 mRNA in CFA-treated mice was similar to that in saline-treated mice at 7 days after CFA injection. The present findings strongly indicate the early intrathecal use of the COX-2 inhibitor for the relief of chronic inflammatory pain. Furthermore, together with the result in a previous study that pro-inflammatory cytokines lead to stimulation of a NF-kappaB-dependent transcriptional pathway, these findings suggest that a spinal cytokine/NF-kappaB/COX-2 pathway may play an important role in the development, but not maintenance, of chronic pain following peripheral tissue inflammation.
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Komi Y, Ohno O, Suzuki Y, Shimamura M, Shimokado K, Umezawa K, Kojima S. Inhibition of Tumor Angiogenesis by Targeting Endothelial Surface ATP Synthase with Sangivamycin. Jpn J Clin Oncol 2007; 37:867-73. [DOI: 10.1093/jjco/hym115] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Deguchi K, Sasaki I, Ikeda K, Shimamura M, Urai Y, Tsukaguchi M, Touge T, Takeuchi H, Kuriyama S. The validity of a hyperventilation test for an investigation of autonomic failure: assessment in patients with multiple system atrophy and Parkinson's disease. Int J Clin Pract 2006; 60:1542-7. [PMID: 16669828 DOI: 10.1111/j.1742-1241.2005.00802.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Although heart rate (HR) responses to hyperventilation (HV) have been used as a cardiovascular autonomic function test, autonomic involvement during HV remains uncertain. To clarify the relationship between autonomic activity and cardiovascular changes during HV, we compared cardiovascular responses during HV among subjects with different autonomic function, namely 16 patients with probable multiple system atrophy (MSA), 16 with possible MSA, 28 with Parkinson's disease (PD) and 28 healthy controls. Abnormalities of cardiovascular responses to head-up postural change and the Valsalva maneuver were definitely present in the order of probable MSA, possible MSA and PD, and abnormal HR and blood pressure (BP) responses during HV were observed in probable MSA and possible MSA, but not in PD. Unlike the significant difference in standard cardiovascular autonomic function tests, the HR and BP responses during HV were equivalent between probable and possible MSA. These findings suggest that cardiovascular control during HV may be affected not only by autonomic activity but also by other factors.
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Nakanishi Y, Oinuma T, Sano M, Fuchinoue F, Komatsu K, Seki T, Obana Y, Tabata M, Kikuchi K, Shimamura M, Ohmori K, Nemoto N. Coexpression of an unusual form of the EWS-WT1 fusion transcript and interleukin 2/15 receptor betamRNA in a desmoplastic small round cell tumour. J Clin Pathol 2006; 59:1108-10. [PMID: 17021139 PMCID: PMC1861750 DOI: 10.1136/jcp.2005.026245] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND The beta chain of the interleukin 2/15 receptor (IL-2/15Rbeta) is induced by the expression of the EWS-WT1. A case of desmoplastic small round cell tumour (DSRCT) expressing only an unusual EWS-WT1 treated by us is reported here. AIM To characterise an unusual form of EWS-WT1. METHODS Frozen tissue sections of the axillary tumour were examined using a laser-assisted microdissection technique and reverse transcriptase polymerase chain reaction. RESULTS The novel fusion of exon 8 of EWS and the defective exon 10 of WT1 (-KTS) was detected. Although it was an unusual form, the coexpression of the present EWS-WT1, IL-2/15Rbeta and Janus kinase (JAK1) mRNA was detected in the tumour cells. IL-2 and signal transducers and activators of transcription (STAT5) mRNA were detected in both tumour and stromal cells. CONCLUSION The induction of the IL-2/15 receptor signalling pathway may contribute to tumorigenesis in DSRCT through a paracrine or an autocrine system, even though the EWS-WT1 was an unusual form.
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Okumura S, Sawada M, Park YW, Hayashi T, Shimamura M, Takase H, Tomizawa KI. Transformation of poplar (Populus alba) plastids and expression of foreign proteins in tree chloroplasts. Transgenic Res 2006; 15:637-46. [PMID: 16952016 DOI: 10.1007/s11248-006-9009-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Accepted: 04/30/2006] [Indexed: 11/28/2022]
Abstract
Plastid transformation offers several unique advantages compared with nuclear genome transformation, such as high level of transgene expression within plastids, expressing multiple transgenes as operons, lack of position effect due to site-specific transgene integration, and reducing risks of gene flow via pollen due to maternal inheritance of the plastid genome. Plastid transformation has been applied to several herbal species, but as yet there are no applications to tree species. We report here the first successful plastid transformation in a tree species, Populus alba. A vector for plastid transformation of poplar (Populus alba) was constructed, which carried the spectinomycin resistance gene and the green fluorescence protein gene as marker genes. In the regenerated shoots, the site-specific integration of foreign genes and the establishment of a high homoplastomic state were confirmed. Immunoblot analysis and histological observations corroborated the accumulation of green fluorescence protein in chloroplasts. The establishment of a plastid transformation system in poplar provides a novel tool for tree biotechnology.
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Koike H, Ishida A, Shimamura M, Mizuno S, Nakamura T, Ogihara T, Kaneda Y, Morishita R. Prevention of onset of Parkinson's disease by in vivo gene transfer of human hepatocyte growth factor in rodent model: a model of gene therapy for Parkinson's disease. Gene Ther 2006; 13:1639-44. [PMID: 16791285 DOI: 10.1038/sj.gt.3302810] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra (SNi). As neurotrophic factors support the survival and enhance the function of dopaminergic neurons, gene therapy using neurotrophic factors has become the center of interest. Thus, we focused on hepatocyte growth factor (HGF) as a neurotrophic and angiogenic growth factor. At 7 days before injection of 6-hydroxydopamine into the SNi, stereotaxic transfection of human HGF or lacZ plasmid was performed into the unilateral striatum of rats. Expression of human HGF in the injected sites could be detected in rats transfected with HGF plasmid DNA, using immunohistochemical staining. Consistently, human immunoreactive HGF protein could be detected at least up to 12 days after transfection. Interestingly, PD rats transfected with lacZ demonstrated amphetamine-induced rotational asymmetry. However, transfection of HGF plasmid DNA resulted in significant inhibition of abnormal rotation up to 24 weeks in a dose-dependent manner. Over 90% of dopaminergic neurons were lost in PD rats transfected with lacZ, whereas over 70% survived in rats transfected with HGF, as assessed by immunohistochemical staining. Overall, the present study demonstrated that overexpression of HGF prevented neuronal death in a PD rat model, providing a potential novel therapy for PD.
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Shimamura M, Shimizu M, Yagami T, Funabashi T, Kimura F, Kuroiwa Y, Misu Y, Goshima Y. L-3,4-dihydroxyphenylalanine-induced c-Fos expression in the CNS under inhibition of central aromatic L-amino acid decarboxylase. Neuropharmacology 2006; 50:909-16. [PMID: 16504219 DOI: 10.1016/j.neuropharm.2006.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2005] [Revised: 12/16/2005] [Accepted: 01/04/2006] [Indexed: 12/01/2022]
Abstract
L-3,4-dihydroxyphenylalanine (DOPA) is a neurotransmitter candidate. To map the DOPAergic system functionally, DOPA-induced c-Fos expression was detected under inhibition of central aromatic L-amino acid decarboxylase (AADC). In rats treated with a central AADC inhibitor, DOPA significantly increased the number of c-Fos-positive nuclei in the paraventricular nuclei (PVN) and the nucleus tractus solitarii (NTS), and showed a tendency to increase in the supraoptic nuclei (SON), but not in the striatum. On the other hand, DOPA with a peripheral AADC inhibitor elevated the level of c-Fos-positive nuclei in the four regions, suggesting that DOPA itself induces c-Fos expression in the SON, PVN and NTS. In rats treated with 6-hydroxydopamine (6-OHDA) to lesion the nigrostriatal dopamine (DA) pathway, DOPA significantly induced c-Fos expression in the four regions under the inhibition of peripheral AADC. However, under the inhibition of central AADC, DOPA did not significantly increase the number of c-Fos-positive nuclei in the four regions, suggesting that DOPA at least in part induces c-Fos expression through its conversion to DA. It was likely that the 6-OHDA lesion enhanced the response to DA, but attenuated that to DOPA itself. In conclusion, we proposed that the SON, PVN and NTS include target sites for DOPA itself.
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Hamanaka Y, Mukai M, Shimamura M, Kitagawa T, Nishida T, Isohashi F, Ito T, Nishizawa Y, Tatsuta M, Matsuda H, Inoue M. Suppression of PI3K/mTOR pathway rescues LLC cells from cell death induced by hypoxia. Biochem Biophys Res Commun 2005; 330:318-26. [PMID: 15781267 DOI: 10.1016/j.bbrc.2005.02.163] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Indexed: 11/18/2022]
Abstract
Cancer cells in solid tumors are challenged by various microenvironmental stresses, including hypoxia, and cancer cells in hypoxic regions are resistant to current cancer therapies. To investigate the mechanism of resistance to hypoxia in cancer cells, we examined mouse Lewis lung carcinoma (LLC) cells, which died due to necrosis at high density under hypoxic but not under normoxic conditions. Levels of mammalian target of rapamycin (mTOR), a central regulator of cellular energy, are reported to be suppressed in hypoxia. We found that phosphorylation of two molecules downstream to it, ribosomal p70 S6 kinase (S6K) and ribosomal protein S6, was markedly suppressed by hypoxia. Overexpression of the active form of S6K increased the sensitivity of LLC cells to hypoxia. On the other hand, inhibition of PI3K or mTOR dramatically reduced hypoxia-induced cell death under hypoxic conditions. Under hypoxic conditions, blockade of the PI3K or mTOR pathway increased levels of intracellular ATP and delayed decreases in pH and glucose level in culture medium, without affecting the cell cycle.
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Shimamura M, Garcia JM, Prough DS, Dewitt DS, Uchida T, Shah SA, Avila MAA, Hellmich HL. Analysis of long-term gene expression in neurons of the hippocampal subfields following traumatic brain injury in rats. Neuroscience 2005; 131:87-97. [PMID: 15680694 DOI: 10.1016/j.neuroscience.2004.10.041] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2004] [Indexed: 01/19/2023]
Abstract
After experimental traumatic brain injury (TBI), widespread neuronal loss is progressive and continues in selectively vulnerable brain regions, such as the hippocampus, for months to years after the initial insult. To clarify the molecular mechanisms underlying secondary or delayed cell death in hippocampal neurons after TBI, we compared long-term changes in gene expression in the CA1, CA3 and dentate gyrus (DG) subfields of the rat hippocampus at 24 h and 3, 6, and 12 months after TBI with changes in gene expression in sham-operated rats. We used laser capture microdissection to collect several hundred hippocampal neurons from the CA1, CA3, and DG subfields and linearly amplified the nanogram samples of neuronal RNA with T7 RNA polymerase. Subsequent quantitative analysis of gene expression using ribonuclease protection assay revealed that mRNA expression of the anti-apoptotic gene, Bcl-2, and the chaperone heat shock protein 70 was significantly downregulated at 3, 6 (Bcl-2 only), and 12 months after TBI. Interestingly, the expression of the pro-apoptotic genes caspase-3 and caspase-9 was also significantly decreased at 3, 6 (caspase-9 only), and 12 months after TBI, suggesting that long-term neuronal loss after TBI is not mediated by increased expression of pro-apoptotic genes. The expression of two aging-related genes, p21 and integrin beta3 (ITbeta3), transiently increased 24 h after TBI, returned to baseline levels at 3 months and significantly decreased below sham levels at 12 months (ITbeta3 only). Expression of the gene for the antioxidant glutathione peroxidase-1 also significantly increased 6 months after TBI. These results suggest that decreased levels of neuroprotective genes may contribute to long-term neurodegeneration in animals and human patients after TBI. Conversely, long-term increases in antioxidant gene expression after TBI may be an endogenous neuroprotective response that compensates for the decrease in expression of other neuroprotective genes.
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Shimamura M, Sato N, Taniyama Y, Yamamoto S, Endoh M, Kurinami H, Aoki M, Ogihara T, Kaneda Y, Morishita R. Development of efficient plasmid DNA transfer into adult rat central nervous system using microbubble-enhanced ultrasound. Gene Ther 2004; 11:1532-9. [PMID: 15269716 DOI: 10.1038/sj.gt.3302323] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although gene therapy might become a promising approach for central nervous system diseases, the safety issue is a serious consideration in human gene therapy. To overcome this problem, we developed an efficient gene transfer method into the adult rat brain based on plasmid DNA using a microbubble-enhanced ultrasound method, since microbubble-enhanced ultrasound has shown promise for transfecting genes into other tissues such as blood vessels. Using the microbubble-enhanced ultrasound method, luciferase expression was increased approximately 10-fold as compared to injection of naked plasmid DNA alone. Interestingly, the site of gene expression was limited to the site of insonation with intracisternal injection, in contrast to previous studies using viruses. Expression of the reporter gene, Venus, was readily detected in the central nervous system. The transfected cells were mainly detected in meningeal cells with intracisternal injection, and in glial cells with intrastriatal injection. There was no obvious evidence of tissue damage by microbubble-enhanced ultrasound. Overall, the present study demonstrated the feasibility of efficient plasmid DNA transfer into the central nervous system, providing a new option for treating various diseases such as tumors.
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Shimamura M, Brown RC, Lemmon BE, Akashi T, Mizuno K, Nishihara N, Tomizawa KI, Yoshimoto K, Deguchi H, Hosoya H, Horio T, Mineyuki Y. Gamma-tubulin in basal land plants: characterization, localization, and implication in the evolution of acentriolar microtubule organizing centers. THE PLANT CELL 2004; 16:45-59. [PMID: 14660802 PMCID: PMC301394 DOI: 10.1105/tpc.016501] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Accepted: 10/21/2003] [Indexed: 05/18/2023]
Abstract
Although seed plants have gamma-tubulin, a ubiquitous component of centrosomes associated with microtubule nucleation in algal and animal cells, they do not have discrete microtubule organizing centers (MTOCs) comparable to animal centrosomes, and the organization of microtubule arrays in plants has remained enigmatic. Spindle development in basal land plants has revealed a surprising variety of MTOCs that may represent milestones in the evolution of the typical diffuse acentrosomal plant spindle. We have isolated and characterized the gamma-tubulin gene from a liverwort, one of the extant basal land plants. Sequence similarity to the gamma-tubulin gene of higher plants suggests that the gamma-tubulin gene is highly conserved in land plants. The G9 antibody to fission yeast gamma-tubulin recognized a single band of 55 kD in immunoblots from bryophytes. Immunohistochemistry with the G9 antibody clearly documented the association of gamma-tubulin with various MTOC sites in basal land plants (e.g., discrete centrosomes with and without centrioles and the plastid surface in monoplastidic meiosis of bryophytes). Changes in the distribution of gamma-tubulin occur in a cell cycle-specific manner during monoplastidic meiosis in the liverwort Dumortiera hirsuta. gamma-Tubulin changes its localization from the plastid surface in prophase I to the spindle, from the spindle to phragmoplasts and the nuclear envelope in telophase I, and back to the plastid surfaces in prophase II. In vitro experiments show that gamma-tubulin is detectable on the surface of isolated plastids and nuclei of D. hirsuta, and microtubules can be repolymerized from the isolated plastids. gamma-Tubulin localization patterns on plastid and nuclear surfaces are not affected by the destruction of microtubules by oryzalin. We conclude that gamma-tubulin is a highly conserved protein associated with microtubule nucleation in basal land plants and that it has a cell cycle-dependent distribution essential for the orderly succession of microtubule arrays.
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Muramatsu T, Ohmori I, Shimamura M, Hasegawa M, Furuichi M, Maekawa Y, Nakamura T, Negishi N. [Complications of video-assisted thoracoscopic surgery]. KYOBU GEKA. THE JAPANESE JOURNAL OF THORACIC SURGERY 2003; 56:920-3. [PMID: 14579693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
We introduced video-assisted thoracoscopic surgery (VATS) for chest disorders in our institution in March, 1992. At first, many of the subjects' disorders were non-malignant diseases such as spontaneous pneumothorax, but later we started to perform this procedure for lung cancer and mediastinum neoplasm, with improved result over thoracoscopic surgical procedures. Now most of the chest disorders at our institution are treated with VATS. However, many kinds of complications due to manual techniques and instrument troubles surfaced during this period. Therefore, in this article we would like to describe the complications that we have experienced in our institution using VATS and discuss how we have attempted to deal with these complications.
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Shimamura M, Nagasawa H, Ashino H, Yamamoto Y, Hazato T, Uto Y, Hori H, Inayama S. A novel hypoxia-dependent 2-nitroimidazole KIN-841 inhibits tumour-specific angiogenesis by blocking production of angiogenic factors. Br J Cancer 2003; 88:307-13. [PMID: 12610518 PMCID: PMC2377039 DOI: 10.1038/sj.bjc.6600667] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Tumour angiogenesis is initiated by angiogenic factors that are produced in large amounts by hypoxic tumour cells. The inhibition of this step may lead to tumour-specific antiangiogenesis because normal tissues are not usually hypoxic. On the other hand, blocking a biological function of endothelial cells is known to result in angiogenic inhibition. To produce a tumour-specific and powerful antiangiogenesis, we determined whether potent angiogenic inhibition could be achieved by inhibiting the production of angiogenic factors by hypoxic tumour cells and simultaneously blocking certain angiogenic steps in endothelial cells under normoxia. We focused on the 2-nitroimidazole moiety, which is easily incorporated into hypoxic cells and exhibits its cytotoxicity as hypoxic cytotoxin. We designed and synthesised 2-nitroimidazole derivatives designated as KIN compounds, and investigated their antiangiogenic activities under normoxia using a chick embryo chorioallantoic membrane. KIN-841 (2-nitroimidazole 1-acetylhydroxamate) showed a potent angiogenic inhibition in a dose-dependent manner. This compound inhibited the proliferation of bovine pulmonary arterial endothelial (BPAE) cells more strongly than that of tumour cells, such as Lewis lung carcinoma (3LL) cells, under normoxia. The inhibition of cell proliferation by KIN-841 under hypoxia increased about five-fold compared to that under normoxia. Moreover, under hypoxia, KIN-841 significantly decreased the excessive production of vascular endothelial cell growth factors induced by 3LL cells as determined by tritium-labelled thymidine ([(3)H]thymidine) incorporation into BPAE cells and by ELISA. Intraperitoneal administration of KIN-841 suppressed 3LL-cell-induced in vivo angiogenesis in the mouse dorsal air sac system. These results indicate that the regulation of the production of angiogenic factors by hypoxic tumour cells is a useful target for tumour-specific angiogenesis inhibition, and that KIN-841, which causes simultaneous direct inhibition of endothelial cell function and production of angiogenic factors by hypoxic tumour cells, is a very potent inhibitor of tumour-specific angiogenesis. Thus, the potential for clinical use of KIN-841 as an antitumour drug is very high.
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Ohta M, Minagi S, Sato T, Okamoto M, Shimamura M. Magnetic resonance imaging analysis on the relationship between anterior disc displacement and balancing-side occlusal contact. J Oral Rehabil 2003; 30:30-3. [PMID: 12485380 DOI: 10.1046/j.1365-2842.2003.01000.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The purpose of this study was to evaluate the relationship between balancing-side occlusal contact patterns and the prevalence of the internal derangement of the temporomandibular joint (TMJ). Forty-one patients were used for the magnetic resonance image (MRI) analysis of TMJ and occlusal examination. Balancing-side occlusal contact patterns observed during mandibular lateral excursive movements were classified into the three following categories: group A, simultaneous balancing-side contact, group B, balancing-side contact (with clenching only) and Group C, no balancing-side contact (with or without clenching). By the occlusal examination of 57 sides, 31.6% showed group A, 8.8% showed group B and 59.6% showed group C contact. Group A could not be observed in the patient group with normal disc position. In the disc displacement group, the prevalence of group A, group B and group C were 40.9, 6.8 and 52.3%, respectively. The higher prevalence of simultaneous balancing-side contact was revealed to be associated with articular disc dislocation.
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Yamamoto Y, Ono H, Ueda A, Shimamura M, Nishimura K, Hazato T. Spinorphin as an endogenous inhibitor of enkephalin-degrading enzymes: roles in pain and inflammation. Curr Protein Pept Sci 2002; 3:587-99. [PMID: 12470213 DOI: 10.2174/1389203023380404] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is possible that enkephalins are involved in the pain-modulating mechanism in the spinal cord. Enkephalins, however, are short-lived, being rapidly degraded by various endogenous enzymes. Many substances that inhibit enkephalin-degradation have been investigated and it has been reported that some inhibitors (e.g. kelatorphan and RB101) alone showed anti-nociceptive activity. We found an endogenous factor that modulated enkephalin-degrading activity and purified it from bovine spinal cord based on its inhibitory activity toward enkephalin-degrading enzymes. Structural analysis revealed the factor to be Leu-Val-Val-Tyr-Pro-Trp-Thr and it was named spinorphin. It has been found that spinorphin inhibited the activity toward various enkephalin-degrading enzymes from monkey brain, especially dipeptidyl peptidase III (DPPIII, Ki=5.1 x 10(-7) M). Recently we reported that this inhibitor significantly inhibited bradykinin (BK)-induced nociceptive flexor responses. Importantly, the mode of inhibition to BK-responses by spinorphin was different from the case with morphine. The morphine-induced blockade of BK-response was attenuated by pertussis toxin treatment, whereas that of spinorphin was not. We also have reported roles for spinorphin in inflammation. Spinorphin significantly inhibited the functions of polymorphonuclear neutrophils (PMNs) by suppressing the binding of fMLF to its receptor on PMNs. Further, this inhibitor suppressed the carrageenan-induced accumulation of PMN in mouse air pouches after intravenous administration. These results indicate that spinorphin may be an endogenous anti-inflammatory regulator. The possible role of spinorphin and its analog as regulators in pain and inflammation will be discussed.
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Shimamura M. [Intra-and extra-thymic development of NKT cells]. TANPAKUSHITSU KAKUSAN KOSO. PROTEIN, NUCLEIC ACID, ENZYME 2001; 46:2171-5. [PMID: 11762077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
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