Plasmablasts as Migratory IgG-Producing Cells in the Pathogenesis of Neuromyelitis Optica

Neuromyelitis optica (NMO) is an inflammatory disease characterized by recurrent attacks of optic neuritis and myelitis. It is generally accepted that autoantibodies against aquaporin 4 water channel protein play a pathogenic role in neuromyelitis optica. We have recently reported that plasmablasts are increased in the peripheral blood of this autoimmune disease, and are capable of producing autoantibodies against aquaporin 4. Here, we demonstrate that CD138⁺HLA-DR⁺ plasmablasts, a subset of IgG-producing cells, are increased in the peripheral blood and are enriched among the cerebrospinal fluid (CSF) lymphocytes during the relapse of neuromyelitis optica. Notably, these CD138⁺HLA-DR⁺ plasmablasts overexpress CXCR3, whose ligands are present in the cerebrospinal fluid during the relapse of neuromyelitis optica. These results led us to speculate that plasmablasts producing anti-aquaporin 4 autoantibodies might traffic toward the central nervous system (CNS). Furthermore, we performed single-cell sorting of plasmablasts from peripheral blood and CSF samples from NMO and sequenced the complementarity-determining regions (CDRs) of the IgG heavy chain expressed by the sorted plasmablast clones. There were high frequencies of mutations in the CDRs compared with framework regions, indicating that these plasmablast clones would represent a post-germinal center B-cell lineage. Consistent with the preceding results, the plasmablast clones from the peripheral blood shared the same CDR sequences with the clones from the CSF. These results indicate that IgG-producing plasmablasts, which are guided by helper T-cells, may migrate from the peripheral blood preferentially to the CSF. Since migratory plasmablasts could be involved in the inflammatory pathology of NMO, the B-cell subset and their migration might be an attractive therapeutic target.     

A New Antitumor Nucleoside, 1-(3-C-Ethynyl-β-d-ribo-pentofuranosyl)-cytosine (ECyd), Is a Potent Inhibitor of RNA Synthesis

Abstract

The antitumor activity, metabolism, and mechanism of action of a newly developed antitumor nucleoside, 1-(3-C-Ethynyl-β-_d-ribo-pentofuranosyl)cytosine (ECyd) are described.     

1,2-Di-O-α-linolenoyl-3-O-β-galactosyl-sn-glycerol as a superoxide generation inhibitor from Perilla frutescens var. crispa

Using a superoxide (O(2)(-)) generation assay system with differentiated HL-60 cells, 1,2-di-O-α-linolenoyl-3-O-β-galactosyl-sn-glycerol (DLGG) was identified as an O(2)(-) generation inhibitor from Perilla frutescens var. crispa (a local variety, kida-chirimen shiso). DLGG suppressed the O(2)(-) level in a dose-dependent manner with an IC(50) value of 21 μM, comparable to those of rosmarinic acid (RoA, IC(50) = 29 μM) and caffeic acid (CA, IC(50) = 30 μM). While RoA and CA also dose-dependently inhibited O(2)(-) generation in a xanthine-xanthine oxidase system, DLGG had no effect in the same system. Thus DLGG appeared to decrease the O(2)(-) level in the HL-60 assay system by mechanisms different from those of RoA and CA, which appeared to act as O(2)(-) scavengers.     

Natural products reveal cancer cell dependence on oxysterol-binding proteins

Cephalostatin 1, OSW-1, ritterazine B and schweinfurthin A are natural products that potently, and in some cases selectively, inhibit the growth of cultured human cancer cell lines. The cellular targets of these small molecules have yet to be identified. We have discovered that these molecules target oxysterol binding protein (OSBP) and its closest paralog, OSBP-related protein 4L (ORP4L)--proteins not known to be involved in cancer cell survival. OSBP and the ORPs constitute an evolutionarily conserved protein superfamily, members of which have been implicated in signal transduction, lipid transport and lipid metabolism. The functions of OSBP and the ORPs, however, remain largely enigmatic. Based on our findings, we have named the aforementioned natural products ORPphilins. Here we used ORPphilins to reveal new cellular activities of OSBP. The ORPphilins are powerful probes of OSBP and ORP4L that will be useful in uncovering their cellular functions and their roles in human diseases.     

Detection of loci for allergic asthma using SMXA recombinant inbred strains of mice

Asthma is regarded as a multifactorial inflammatory disorder arising as a result of inappropriate immune responses in genetically susceptible individuals to common environmental antigens. However, the precise molecular basis is unknown. To identify genes for susceptibility to three asthma-related traits, airway hyperresponsiveness (AHR), eosinophil infiltration, and allergen-specific serum IgE levels, we conducted a genetic analysis using SMXA recombinant inbred (RI) strains of mice. Quantitative trait locus analysis detected a significant locus for AHR on chromosome 17. For eosinophil infiltration, significant loci were detected on chromosomes 9 and 16. Although we could not detect any significant loci for allergen-specific serum IgE, analysis of consomic strains showed that chromosomes 17 and 19 carried genes that affected this trait. We detected genetic susceptibility loci that separately regulated the three asthma-related phenotypes. Our results suggested that different genetic mechanisms regulate these asthma-related phenotypes. Genetic analyses using murine RI and consomic strains enhance understanding of the molecular mechanisms of asthma in human.     

A series of thiazole derivatives bearing thiazolidin-4-one as non-competitive ADAMTS-5 (aggrecanase-2) inhibitors

A series of thiazole bearing thiazolidin-4-one was discovered via high-throughput screening as non-competitive inhibitors of ADAMTS-5. Compound 31 appeared to give the best ADAMTS-5 inhibition and good selectivity over other metalloproteases.     

Genetic Block of l-Glycerol-3-phosphate: NADP Oxidoreductase in the l-Glutamic Acid-producing Glycerol Auxotroph

Investigations were carried out to detect a blocked step in the glycerol biosynthesis of the glycerol auxotroph GL-21 derived from Corynebacterium alkanolyticum No. 314.

The enzyme required for the conversion of dihydroxyacetone phosphate to α-glycerophosphate was assumed to be defective, because some of glycerol derivatives and glycerol analogues substituted for glycerol as a growth factor, in which glycerides, phospholipids, surfactants and intermediary metabolites in the glycolysis pathway were included.

To confirm this assumption, the activities of α-glycerophosphate dehydrogenase of the mutant were compared to those of the parent. From these results, the auxotroph GL-21 was found to be deficient for a specific l-glycerol-3-phosphate: NADP oxidoreductase which is indispensable for the synthesis of glycerol.     

Relation between the Extracellular Accumulation of L-Glutamic Acid and the Excretion of Phospholipids by Penicillin-treated Corynebacterium alkanolyticum

The addition of penicillin (50 u/ml) to the cells of Corynebacterium alkanolyticum No. 314 growing on n-paraffins medium at the logarithmic growth phase was the most suitable for the extracellular accumulation of L-glutamic acid and the excretion of phospholipids.

The relation between the extracellular accumulation L-glutamic acid and the excretion of phospholipids in the presence of penicillin was very close and specific. The kinds of phospholipids excreted and their fatty acid components were the same as those of intracellular phospholipids.     

Effects of age,body size and season on food consumption and digestion of captive dugongs (Dugong dugon)

Food consumption and digestion of male and female dugongs (Dugong dugon) was examined by analyzing long-term (1979–1998) feeding records at Toba Aquarium (Japan). Throughout all captive feeding periods, dugongs consumed eelgrass (Zostera marina) and showed steady increases in feed consumption with a consistent weight gain of 42–45?kg a year. The daily consumption of male and female dugongs increased from 10–15?kg to 23–26?kg of fresh eelgrass, accounting for approximately 14 and 7% of their body weight at one and seven years old, respectively. Both dugongs had a marginal dry matter digestibility of over 90%. Food consumption varied between seasons and individuals. There were major reductions (P<0.05) in consumption by the male in November and January and by the female in August and September. The seasonal reductions in food consumption coincided with high digestibility of eelgrass.