A potent and selective nonpeptide antagonist of CXCR2 inhibits acute and chronic models of arthritis in the rabbit

Much evidence implicates IL-8 as a major mediator of inflammation and joint destruction in rheumatoid arthritis. The effects of IL-8 and its related ligands are mediated via two receptors, CXCR1 and CXCR2. In the present study, we demonstrate that a potent and selective nonpeptide antagonist of human CXCR2 potently inhibits (125)I-labeled human IL-8 binding to, and human IL-8-induced calcium mobilization mediated by, rabbit CXCR2 (IC(50) = 40.5 and 7.7 nM, respectively), but not rabbit CXCR1 (IC(50) = >1000 and 2200 nM, respectively). These data suggest that the rabbit is an appropriate species in which to examine the anti-inflammatory effects of a human CXCR2-selective antagonist. In two acute models of arthritis in the rabbit induced by knee joint injection of human IL-8 or LPS, and a chronic Ag (OVA)-induced arthritis model, administration of the antagonist at 25 mg/kg by mouth twice a day significantly reduced synovial fluid neutrophils, monocytes, and lymphocytes. In addition, in the more robust LPS- and OVA-induced arthritis models, which were characterized by increased levels of proinflammatory mediators in the synovial fluid, TNF-alpha, IL-8, PGE(2), leukotriene B(4), and leukotriene C(4) levels were significantly reduced, as was erythrocyte sedimentation rate, possibly as a result of the observed decreases in serum TNF-alpha and IL-8 levels. In vitro, the antagonist potently inhibited human IL-8-induced chemotaxis of rabbit neutrophils (IC(50) = 0.75 nM), suggesting that inhibition of leukocyte migration into the knee joint is a likely mechanism by which the CXCR2 antagonist modulates disease.     

Human B cells immortalized with Epstein-Barr virus upregulate CCR6 and CCR10 and downregulate CXCR4 and CXCR5

Compared to peripheral blood resting B cells, Epstein-Barr virus (EBV)-immortalized B cells consistently express CCR6 and CCR10 at high levels and CXCR4 and CXCR5 at low levels. Accordingly, these cells vigorously responded to the ligands of CCR6 and CCR10 but not to those of CXCR4 and CXCR5. In a human EBV-negative B-cell line, BJAB, stable expression of EBNA2 upregulated CCR6, while stable expression of EBNA2 as well as LMP1 downregulated CXCR4. On the other hand, upregulation of CCR10 or downregulation of CXCR5 was not induced in BJAB by stable expression of EBNA2 or LMP1. Thus, these changes may be due to a plasmablast-like stage of B-cell differentiation fixed by EBV immortalization. EBV-infected B cells in infectious mononucleosis are known to avoid germinal centers and accumulate under the mucosal surfaces. EBV-associated opportunistic lymphomas also tend to occur in extranodal sites. These preferred sites of in vivo localization are consistent with the unique profile of chemokine receptor expression exhibited by EBV-immortalized B cells.     

Identification and characterization of the UL56 gene product of herpes simplex virus type 2

The UL56 gene product of herpes simplex virus (HSV) has been shown to play an important role in viral pathogenicity. However, the properties and functions of the UL56 protein are little understood. We raised rabbit polyclonal antisera specific for the UL56 protein of HSV type 2 (HSV-2) and examined its expression and properties. The gene product was identified as three polypeptides with apparent molecular masses ranging from 32 to 35 kDa in HSV-2-infected cells, and at least one species was phosphorylated. Studies of their origins showed that the UL56 protein of HSV-2 is also translated from the upstream in-frame methionine codon that is not present in the HSV-1 genome. Synthesis was first detected at 6 h postinfection and was not abolished by the viral DNA synthesis inhibitor phosphonoacetic acid. Indirect immunofluorescence studies revealed that the UL56 protein localized to both the Golgi apparatus and cytoplasmic vesicles in HSV-2-infected and single UL56-expressing cells. Deletion mutant analysis showed that the C-terminal hydrophobic region of the protein was required for association with the cytoplasmic membrane and that the N-terminal proline-rich region was important for its translocation to the Golgi apparatus and cytoplasmic vesicles. Moreover, the results of protease digestion assays and sucrose gradient fractionation strongly suggested that UL56 is a tail-anchored type II membrane protein associated with lipid rafts. We thus hypothesized that the UL56 protein, as a tail-anchored type II membrane protein, may be involved in vesicular trafficking in HSV-2-infected cells.     

Sphingomyelinase amplifies BMP-4-induced osteocalcin synthesis in osteoblasts: role of ceramide

We previously reported that extracellular sphingomyelinase induces sphingomyelin hydrolysis in osteoblast-like MC3T3-E1 cells and that mitogen-activated protein (MAP) kinases are involved in bone morphogenetic protein (BMP)-4-stimulated osteocalcin synthesis in these cells. In the present study, we investigated whether sphingomyelinase affects BMP-4-stimulated synthesis of osteocalcin in osteoblast-like MC3T3-E1 cells. Sphingomyelinase significantly enhanced the BMP-4-stimulated osteocalcin synthesis. Among sphingomyelin metabolites, C(2)-ceramide enhanced the BMP-4-stimulated osteocalcin synthesis while sphingosine and sphingosine 1-phosphate had little effect on the synthesis. D-erythro-MAPP, an inhibitor of ceramidase, amplified the sphingomyelinase-effect on the osteocalcin synthesis. C(2)-ceramide suppressed the BMP-4-induced phosphorylation of p44/p42 MAP kinase, while having little effect on the phosphorylation of Smad1 and p38 MAP kinase. Taken together, our results strongly suggest that extracellular sphingomyelinase enhances the BMP-stimulated osteocalcin synthesis via ceramide in osteoblasts and that the effect of ceramide is exerted at a point upstream from p44/p42 MAP kinase.     

Synthesis of the (17R)- and (17S)-isomers of volicitin,an elicitor of plant volatiles contained in the oral secretion of the beet armyworm

Both the (17R)- and (17S)-isomers of volicitin, which is contained in the oral secretion of the beet armyworm and induces corn seedlings to emit a blend of volatile compounds to attract the natural enemy of the herbivore, were synthesized via the semi-hydrogenation of an intermediary diyne and (Z)-selective olefination as the key steps. They were both obtained as crystalline compounds.     

A simple method for enrichment of uninucleate conidia of Aspergillus oryzae

Aspergillus oryzae produces multinucleate conidia, which makes the obtaining of homokaryons labor-intensive. Analysis of conidia by flow cytometry clarified the relationship that conidia of lower nuclear number were smaller in size. Based on this, we have developed a simple way to enrich uninucleate conidia with a membrane filter. Our results also suggest that the method is useful for elimination of heterokaryons.     

Identification of the sex pheromone components secreted by female moths of Peridroma saucia (Noctuidae: Noctuinae)

The variegated cutworm, Peridroma saucia Hübner, is a lepidopteran pest to a large number of crops in Canada, the United States, and Europe. It was probably naturalized in Japan in the 1970s. The pheromone glands of the female moth include two components with electroantennographic activity in a ratio of 3:1. GC-MS analyses of pheromone extracts untreated and treated with dimethyl disulfide revealed the major component to be (Z)-11-hexadecenyl acetate and the minor component to be (Z)-9-tetradecenyl acetate. The synthetic pheromone was used to attract a large number of males in a vegetable field in Tokyo, which suggests that this species has already become a harmful pest in Japan.     

Purification and characterization of a lipase from the glycolipid-producing yeast Kurtzmanomyces sp. I-11

An extracellular lipase produced by the glycolipid-producing yeast Kurtzmanomyces sp. I-11 was purified by ammonium sulfate precipitation and column chromatographies on DEAE-Sephadex A-25, SP-Sephadex C-50, and Sephadex G-100. Based on the analysis of the purified lipase on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified lipase was judged to be homogeneous and its molecular mass was estimated to be approximately 49 kDa. The optimum temperature for the activity was 75 degrees C, and the activity was very stable at temperatures below 70 degrees C. The active pH range of this lipase was 1.9-7.2, and the activity was stable at pH below 7.1. The lipase showed a preference for C18 acyl groups by measurements with p-nitrophenyl esters and triglycerides as substrates. The lipase was very stable in the presence of various organic solvents at a concentration of 40%. Although the N-terminal sequence of the Kurtzmanomyces lipase was very similar to that of lipase A from Candida antarctica, the pH profiles of the two lipases were significantly different.