Association study of a functional catechol-O-methyltransferase gene polymorphism in Japanese schizophrenics

Catechol-O-methyltransferase (COMT) is an enzyme which inactivates catecholamine neurotransmitters by methylation, and is considered a candidate for involvement in schizophrenia. A functional COMT gene polymorphism influencing the enzyme activities, the high activity (val-108) and the low activity allele (met-108), was recently confirmed. We investigated a genetic association between schizophrenia and the COMT gene polymorphism in 150 Japanese schizophrenics and controls. We detected the low activity met-108 allele more frequently in schizophrenics than in the controls, and found that subjects sharing the met-108 allele (val/met and met/met) are significantly more common in the patients than in the controls. The results suggest that the low activity met-108 allele may be involved in susceptibility for schizophrenia.

Neuropathological and molecular studies of spinocerebellar ataxia type 6 (SCA6)

SCA6 is an autosomal dominant spinocerebellar ataxia (SCA) caused by a small CAG repeat expansion of the gene encoding an alpha-1A-voltage-dependent Ca channel gene subunit on chromosome 19p13. A Japanese woman with SCA6, with a 7-year history of progressive pure cerebellar ataxia, died of malignant lymphoma. Systematic neuropathological examination showed that neuronal degeneration was confined to the cerebellar Purkinje cells and, to a lesser degree, the granular cells, without any involvement of other central nervous system structures. Such pathological selectivity correlates with the localized expression of the responsible gene, and coincides with the neurological manifestation. These findings might contribute to establishing the phenotype of the SCA6 via comparison with other dominant ataxias.

Development of a fluorescent indicator for nitric oxide based on the fluorescein chromophore

Endogenous nitric oxide (NO) appears to modulate many physiological and pathophysiological processes. In order to obtain direct evidence for NO functions in vivo, we have developed 4,5-diaminofluorescein (DAF-2) as a novel fluorescent indicator for NO. Green-fluorescent triazolofluorescein formed by the reaction of NO and DAF-2 affords high sensitivity for NO (detection limit: 5 nM). Membrane-permeable DAF-2 diacetate (DAF-2 DA) was loaded into activated rat aortic smooth muscle cells, where the ester bonds are hydrolyzed by intracellular esterase, generating DAF-2. The fluorescence in the cells increased in a NO concentration-dependent manner. This imaging method should be useful for studies of the dynamic biological actions of NO at the molecular level with fine temporal and spatial resolution.

An mRNA of tobacco cell, which is rapidly inducible by methyl jasmonate in the presence of cycloheximide, codes for a putative glycosyltransferase

Two-dimensional gel electrophoretic display of polypeptides labeled in vivo and those synthesized in vitro from poly(A)(+)-RNA indicated that treatment of cultured cells of tobacco (Nicotiana tabacum) BY-2 with methyl jasmonate (MeJA) induces accumulation of a limited number of specific mRNAs within a few hours. The MeJA-induction of most of these mRNAs was inhibited by cycloheximide (CHX). Six MeJA-inducible cDNAs identified by differential screening were classified into three groups based on the sensitivity of their induction to CHX. Induction of group I mRNAs by MeJA occurred earlier than the induction of other mRNAs and it was not inhibited by CHX. The induction of group II mRNAs by MeJA was blocked by CHX, while group III mRNAs were induced by CHX alone. One group I cDNA was found to encode a putative protein, JIGT, homologous to UDP-sugar glycosyltransferases previously characterized from several plant species. JIGT was structurally different from a putative glycosyltransferase that is rapidly inducible by salycylic acid (SA) in BY-2 cells. JIGT mRNA was not induced by SA. In addition to MeJA, as little as 10(-9) M coronatine induced JIGT mRNA. A sequence highly homologous to JIGT is present as a single copy in the genomes of Nicotiana sylvestris and N. tomentosiformis. The MeJA-inducible production of JIGT may be involved in sugar-conjugation of an unknown substrate in a defensive response and expression of the gene for JIGT in BY-2 cells might serve as a good model system for disecting molecular events occurring in JA-inducible gene expression.

Three-dimensional structure of a glycosphingolipid having a novel carbohydrate linkage, Galbeta1-4(Fucalpha1-3)Glcbeta1-3Galbeta, determined by theoretical calculations

The novel glycosphingolipid, SEGLx (Galbeta1-4(Fucalpha1-3)Glcbeta1-3GalbetaCer), which was identified by us (Kawakami Y, et al. (1993) J Biochem 114: 677-83), shows a characteristic spectrum on 1H-NMR analysis, in which the anomeric proton resonances of a reducing end galactose and a glucose are split. To elucidate the structural characteristics of SEGLx, we determined its three-dimensional (3D) structure by means of computer simulation, involving such techniques as molecular mechanics (MM2), the semiempirical molecular orbital method (AM1), molecular dynamics (Amber), and computer 3D modelling. With the hypothesis that all OH group(s) of a ceramide participate in intramolecular hydrogen bonds, two kinds of stable conformers, horizontal and right-angled ones, were formed, depending on the ceramide species. The present findings suggest that the chemical species of both the long chain base and fatty acid moieties, mainly the occurrence of OH group(s), affect the chemical shifts of the anomeric proton resonances not only of the reducing terminal galactose but also the penultimate glucose through the formation of intramolecular hydrogen bonds. Computer simulation through theoretical calculation and 3D modelling was shown to be the best means of confirming the results obtained by experimental analysis.

Simultaneous observation of individual ATPase and mechanical events by a single myosin molecule during interaction with actin

We have developed a technique that allows mechanical and ligand-binding events in a single myosin molecule to be monitored simultaneously. We describe how steps in the ATPase reaction are temporally related to mechanical events at the single molecule level. The results show that the force generation does not always coincide with the release of bound nucleotide, presumably ADP. Instead the myosin head produces force several hundreds of milliseconds after bound nucleotide is released. This finding does not support the widely accepted view that force generation is directly coupled to the release of bound ligands. It suggests that myosin has a hysteresis or memory state, which stores chemical energy from ATP hydrolysis.

[Efficacy of granisetron, a 5-HT3 antagonist, in the prevention of nausea and vomiting induced by conditioning for hematopoietic stem cell transplantation]

One hundred and eleven patients receiving conditioning regimens for hematopoietic stem cell transplantation (HSCT) were administered a single intravenous dose (40 micrograms/kg) of granisetron before chemo-radio therapy. The efficacy of the drug was assessed every 24 hours, rating the control of nausea and vomiting as complete, major, minor or failure. On day 1, 23 of 48 patients (47.9%) who received cyclophosphamide (60 mg/kg/day), achieved control of emesis with complete or major response. On day 2, 17 of 47 patients (36.2%) achieved control emesis. During total body irradiation (TBI) (10 approximately 12 Gy/2 approximately 3 days), 21 of 33 patients (63.6%) achieved control of emesis on day 1 and 22 of 32 patients (68.6%) achieved control of emesis on day 2. During melphalan administration (60 approximately 100 mg/m2/day), 20 of 28 patients (71.4%) achieved control of emesis on day 1. Adverse effects were observed in seven patients but were not serious. We concluded that granisetron has a major role in preparation for HSCT.

Development of a fluorescent indicator for the bioimaging of nitric oxide

Nitric oxide (NO) has been reported to play various roles as a signal transmitter. However, detailed functions of NO have yet to be clarified. We have developed a fluorescent indicator for NO imaging in living cells. The N-nitrosation of newly designed and synthesized 4-((3-amino-2-naphthyl)aminomethyl)benzoic acid (DAN-1) by NO yielded the highly fluorescent triazole-form. The membrane permeable ester derivative of DAN-1 (DAN-1 EE) was applied to the imaging of NO produced in activated rat aortic smooth muscle cells. After DAN-1 EE has been loaded into cells, the ester bond is hydrolyzed by intracellular esterase, yielding original DAN-1 with less permeability. The fluorescence intensity of the cells loaded with DAN-1 EE increased according to NO production. The imaging method with fluorescent indicators will be significant for the functional clarification of NO in vivo.

[Quantitative determination of serum anti ribosomal-P protein antibody by enzyme immunoassay]

An enzyme immunoassay for serum anti-ribosomal P protein antibodies (anti-P) is developed, using highly purified synthetic ribosomal P peptides of the carboxyl terminal 22 amino acid sequence conjugated to human serum albumin (HSA) as an antigen. Anti-P levels were determined by subtracting the nonspecific binding activities to HSA. The concentration of anti-P which produced half of the maximal absorbance at 492 nm (OD492) given by saturating concentrations of anti-P in the ELISA plate was defined as 1 U/ml. The anti-P values in the samples were determined by referring to a standard curve made from a standard serum containing anti-P. Serum anti-P levels in 34 normal individuals were 5.52 +/- 8.39 U/ml (mean +/- SD). Anti-P in sera from 45 patients with systemic lupus erythematosus (SLE), 24 patients with rheumatoid arthritis (RA) and 27 patients with Behçet's disease were also analyzed. The values for serum anti-P in SLE, RA and Behçet's disease groups were 251.04 +/- 843.07 U/ml, 5.97 +/- 15.18 U/ml, and 2.62 +/- 3.35 U/ml (mean +/- SD) respectively. The positive ratio for serum anti-P in SLE patients was significantly higher than that in patients with RA or Behçet's disease (p < 0.05 as determined by chi-square test). These results indicate that quantitative determination of serum anti-P by our enzyme immunoassay is a successful tool for the diagnosis of SLE.

Proliferative effects of several hematopoietic growth factors on acute myelogenous leukemia cells and correlation with treatment outcome

The response of human acute myelogenous leukemia (AML) cells to four different hematopoietic growth factors (granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 beta (IL-1beta), interleukin-3 (IL-3), and stem cell factor (SCF)) and the relationship of the proliferative response of the AML cells to treatment outcome were studied. Proliferative responses were analyzed in 79 patients with de novo AML and 19 patients with AML arising from myelodysplastic syndrome (MDS). In de novo AML, a positive proliferative response (stimulation index >2) was seen in 65 to 75% of cases. AML cells arising from MDS had a much higher incidence of proliferative response to each growth factor (79 to 90%) and a much higher level of 3H-TdR incorporation. The relationship to treatment outcome was evaluated in 79 patients with de novo AML. The patients whose leukemic cells had a positive proliferative response to any growth factor, especially IL-3 and SCF, had a poorer outcome, ie a lower complete remission (CR) rate, shorter CR duration, and shorter survival. The outcome was particularly poor in patients whose leukemic cells had proliferative responses to all four or any of the growth factors, compared to patients whose leukemic cells had no response. This increased response may be a marker of poor prognosis in patients with AML.

Ultrastructural localization of alpha 1-syntrophin and neuronal nitric oxide synthase in normal skeletal myofiber, and their relation to each other and to dystrophin

We investigated the ultrastructural localization of alpha 1-syntrophin and neuronal nitric oxide synthase (nNOS) in normal human skeletal myofibers and analyzed their relation to each other and to dystrophin using single and double immunogold-labeling electron microscopy. Single immunolabeling showed antibodies to alpha 1-syntrophin and nNOS on the inner surface of the muscle plasma membrane, the sarcoplasmic side of plasma membrane invaginations, and the sarcoplasm near mitochondria of subsarcolemmal areas. The epitopes of alpha 1-syntrophin and nNOS tended to be present in clusters. Double immunolabeling revealed that epitope combinations of alpha 1-syntrophin-dystrophin, alpha 1-syntrophin-nNOS, and nNOS-dystrophin occurred more frequently in doublet form than did other epitope combinations, such as alpha 1-syntrophin-beta- spectrin and nNOS-beta-spectrin. These increased frequencies were noted both at the muscle plasma membrane undercoat and near mitochondria of subsarcolemmal areas. A significantly higher percentage of doublets comprised antibodies against alpha 1-syntrophin and dystrophin (28.5 +/- 1.5%, group mean +/- SE) than those against alpha 1-syntrophin and beta-spectrin (9.2 +/- 0.8%, P < 0.01). Furthermore, nNOS formed doublets significantly more frequently with dystrophin (25.2 +/- 3.3%) and alpha 1-syntrophin (26.0 +/- 4.1%) than with beta-spectrin (13.9 +/- 2.3%; P < 0.05). These data support the association of dystrophin, alpha 1-syntrophin, and nNOS at the inner surface of the muscle plasma membrane and near mitochondria of subsarcolemmal areas of normal human skeletal myofibers.

The dual functions of Tetrahymena citrate synthase are due to the polymorphism of its isoforms

Previous studies have shown that Tetrahymena citrate synthase and the Tetrahymena 14-nm filament protein are encoded by a single gene and translated from one species of mRNA, and that they are identical in terms of molecular weight, antigenicity, and some enzymatic properties. In this study, using two-dimensional gel electrophoresis, we demonstrated that the citrate synthase comprised pI 7.7 and 8.0 isoforms, while the 14-nm filament protein comprised three isoforms with isoelectric points of 7.7, 8.0, and 8.4. The amino acid sequences of the NH2-terminal portions of all isoforms were identical and the peptide maps with V8 protease were almost the same. In addition, when the citrate synthase activity of each isoform was measured after separation by non-urea isoelectric focusing without denaturing treatment, the pI 7.7 and/or pI 8.0 isoforms exhibited the citrate synthase activity, but the pI 8.4 isoform only found for the 14-nm filament protein did not possess this activity. These results suggest that the polymorphism of these isoforms is caused by some posttranslational modifications, and that it may have resulted in the different compartmentalization and functions of Tetrahymena citrate synthase and the 14-nm filament protein.

Idiopathic CD4+ T-lymphocytopenia with Bowen's disease

A 39-year-old man with Bowen's disease was troubled with multiple molluscum contagiosum over the trunk and lower extremities. Subsequently oral candidiasis was complicated. Laboratory examination revealed lymphocytopenia and a decrease in the CD4/CD8 ratio. His CD4+ T-lymphocyte count was only 187 cells/microl one time and 222 cells/microl another time. No evidence for human immunodeficiency virus (HIV) infection was found. He had no family history of immunodeficiencies.

Purification and characterization of the human interleukin-18 receptor

Interleukin (IL)-18 was identified as a molecule that induces IFN-gamma production and enhances NK cell cytotoxicity. In this paper, we report upon the purification and characterization of human IL-18 receptor (hIL-18R). We selected the Hodgkin's disease cell line, L428, as the most strongly hIL-18R-expressing cell line based on the results of binding assays. This binding was inhibited by IL-18 but not by IL-1beta. The dissociation constant (Kd) of 125I-IL-18 binding to L428 cells was about 18.5 nM, with 18,000 binding sites/cell. After immunizing mice with L428 cells and cloning, a single monoclonal antibody (mAb) against hIL-18R was obtained (mAb 117-10C). Sequentially, hIL-18R was purified from 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS)-extracted L428 cells by wheat germ lectin-Sepharose 4B chromatography and mAb 117-10C-Sepharose chromatography. The internal amino acid sequences of hIL-18R all matched those of human IL-1 receptor-related protein (IL-1Rrp), the ligand of which was unknown to date. When expressed in COS-1 cells, the cDNA of IL-1Rrp conferred IL-18 binding properties on the cells and the capacity for signal transduction. From these results, we conclude that a functional IL-18 receptor component is IL-1Rrp.

Memory of extracellular adenosine A2A purinergic receptor-mediated signaling in murine T cells

Accumulation of extracellular and intracellular adenosine (Ado) under hypoxic conditions or in the absence of adenosine deaminase results in lymphocyte depletion and in severe combined immunodeficiency, which are currently explained by direct intracellular lymphotoxicity of Ado metabolites. In support of the alternative, "signaling" mechanism, we show that extracellular Ado (extAdo) suppresses all tested T cell receptor (TCR)-triggered effector functions of T lymphocytes including the TCR-triggered FasL mRNA up-regulation in cytotoxic T lymphocytes. Strong evidence against the intracellular lymphotoxicity of Ado (and in support of the signaling model) is provided by abrogation of TCR-triggered growth inhibition in Ado-exposed T cells. The brief exposure to Ado was sufficient to observe inhibition of TCR-triggered effector functions. The "memory" of T cells to exposure to extAdo is best explained by sustained increases in cAMP. Selective agonist (CGS21680) and antagonist (ZM241385) of A2A adenosine receptor were used in functional assays and cDNA probes for different sybtypes of adenosine receptors were used in Northern blot studies. A2A receptors are identified as the predominantly expressed subtype of Gs-coupled Ado receptors in T cells. The demonstration of cross-talk between the A2A receptors and TCR in both directions support the possible role of A2A receptors in mechanisms of extAdo-mediated immunosuppression in vivo under adenosine deaminase deficiency and hypoxic conditions in, e.g., solid tumors.

A comparative study of 2',3'-cyclic-nucleotide 3'-phosphodiesterase in vertebrates: cDNA cloning and amino acid sequences for chicken and bullfrog enzymes

In mammalian brain, two 2',3'-cyclic-nucleotide 3'-phosphodiesterase (EC 3.1.4.37) isoforms, CNP1 and CNP2, are translated, respectively, from the two mRNAs, which have been transcribed and processed by alternative use of the two transcription start points and by differential splicing. In the present study, the cDNAs encoding chicken CNP2 and bullfrog CNP1, respectively, were isolated, and the amino acid sequences of chicken CNP2 and bullfrog CNP1 were deduced. Western blot analysis showed that chicken brain contains a major CNP2-type protein together with a minor unidentified isoform, and bullfrog brain contains only a CNP1-type protein. All available amino acid sequences of vertebrate 2',3'-cyclic-nucleotide 3'-phosphodiesterases were aligned and compared. Three conserved motif sequences were noted: (a) an ATP-binding site near the amino terminus, (b) an isoprenylation site at the carboxyl terminus, and (c) a probable catalytic site resembling the active site of beta-ketoacyl synthase (EC 2.3.1.41). The second and the third motifs are conserved also in goldfish RICH (regeneration-induced 2',3'-cyclic-nucleotide 3'-phosphodiesterase homologue), which has been shown recently to have 2',3'-cyclic-nucleotide 3'-phosphodiesterase activity. The third motif (probably catalytic site) was assigned for the first time in the present report.

Mechanics of single kinesin molecules measured by optical trapping nanometry

We have analyzed the mechanics of individual kinesin molecules by optical trapping nanometry. A kinesin molecule was adsorbed onto a latex bead, which was captured by an optical trap and brought into contact with an axoneme that was bound to a glass surface. The displacement of kinesin during force generation was determined by measuring the position of the beads with nanometer accuracy. As the displacement of kinesin was attenuated because of the compliance of the kinesin-to-bead and kinesin-to-microtubule linkages, the compliance was monitored during force generation and was used to correct the displacement of kinesin. Thus the velocity and the unitary steps could be obtained accurately over a wide force range. The force-velocity curves were linear from 0 to a maximum force at 10 microM and 1 mM ATP, and the maximum force was approximately 7 pN, which is larger by approximately 30% than values previously reported. Kinesin exhibited forward and occasionally backward stepwise displacements with a size of approximately 8 nm. The histograms of step dwell time show a monotonic decrease with time. Model calculations indicate that each kinesin head steps by 16-nm, whereas kinesin molecule steps by 8-nm.

Real-time measurement of nitric oxide production in rat brain by the combination of luminol-H2O2 chemiluminescence and microdialysis

A chemiluminescence method of detecting nitric oxide (NO) in combination with a microdialysis technique was employed for the real-time measurement of NO production in living rat brain. This method based on the luminol-H2O2 system has a detection limit of 1 nM, and is the most sensitive method currently available for measuring NO. We applied this new technique to rat cerebellum to record the increase of chemiluminescence intensity arising from NO production after the injection of N-methyl-D-aspartate or kainic acid around the microdialysis probe. This highly sensitive method should be useful for the direct clarification of the functions of NO in the central nervous system.

Adenovirus-mediated transduction with human glial cell line-derived neurotrophic factor gene prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced dopamine depletion in striatum of mouse brain

As a novel trial of neuroprotective therapy of neurodegenerative diseases, we have constructed a recombinant adenovirus vector (rAdv) bearing a neurotrophic factor gene to deliver the factor to rescue neurons in vivo. In the present study, human glial cell line-derived neurotrophic factor (hGDNF) was chosen to examine the applicability of our strategy to a mouse model of Parkinson's disease. During the construction of the rAdv, we found that the strong constitutive hGDNF expression unit somehow inhibited the appearance of the rAdv. Therefore we adopted a self-contained tetracycline-regulated expression system to acquire an rAdv expressing hGDNF. By analyzing the condition medium of SH-SY5Y cells infected with our constructed virus vector, we confirmed that biologically active GDNF was successfully expressed in vitro. For an animal study, we delivered this virus vector directly to the C57 black mouse brain and then exposed the animal to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to injure the nigrostriatal dopaminergic neurons. One week after the MPTP exposure, the neuroprotective effect of the virus vector was estimated by measurement of the dopamine content in the striatum of the mouse brain. The mice that had received our constructed virus had significantly higher dopamine levels in their striatum, demonstrating that our rAdv expressing hGDNF has therapeutic potential to protect the nigrostriatal dopaminergic neurons in vivo.

Leukocyte function-associated antigen-1-dependent lysis of Fas+ (CD95+/Apo-1+) innocent bystanders by antigen-specific CD8+ CTL

Exquisite specificity toward Ag-bearing cells (cognate targets) is one of the most important properties of CD8+ CTL-mediated cytotoxicity. Using highly Ag-specific CD8+ CTL lines and clones, which spare noncognate, Ag-free targets, we found that in the presence of Ag-bearing targets the CTL acquire the ability to lyse noncognate target cells (bystanders). It is shown that the unexpectedly rapid and efficient lysis of bystanders by Ag-activated CTL is mediated by a Fas ligand (FasL)/Fas-based mechanism and does not depend on perforin. The CTL lysed Fas-expressing bystanders, but spared the Fas-negative or anti-Fas mAb-resistant bystander cells. Accordingly, the FasL-deficient gld/gld CTL did not kill bystanders, while perforin-deficient CTL did. Unlike anti-Fas mAb-induced cell death, the lysis of bystanders was not only FasL/Fas dependent but also required adhesion molecule LFA-1 on the surface of the activated CTL. Lysis of bystanders is viewed as acceptable "collateral" damage, but the persistent presence of activated CTL could result in immunopathologies involving functional Fas-expressing tissues.

Leukocyte function-associated antigen-1-dependent lysis of Fas+ (CD95+/Apo-1+) innocent bystanders by antigen-specific CD8+ CTL

Exquisite specificity toward Ag-bearing cells (cognate targets) is one of the most important properties of CD8+ CTL-mediated cytotoxicity. Using highly Ag-specific CD8+ CTL lines and clones, which spare noncognate, Ag-free targets, we found that in the presence of Ag-bearing targets the CTL acquire the ability to lyse noncognate target cells (bystanders). It is shown that the unexpectedly rapid and efficient lysis of bystanders by Ag-activated CTL is mediated by a Fas ligand (FasL)/Fas-based mechanism and does not depend on perforin. The CTL lysed Fas-expressing bystanders, but spared the Fas-negative or anti-Fas mAb-resistant bystander cells. Accordingly, the FasL-deficient gld/gld CTL did not kill bystanders, while perforin-deficient CTL did. Unlike anti-Fas mAb-induced cell death, the lysis of bystanders was not only FasL/Fas dependent but also required adhesion molecule LFA-1 on the surface of the activated CTL. Lysis of bystanders is viewed as acceptable "collateral" damage, but the persistent presence of activated CTL could result in immunopathologies involving functional Fas-expressing tissues.