Characterization of the binding of botulinum type B 16S toxin to human intestinal epithelial cells

Botulinum neurotoxin produced by Clostridium botulinum type B is a complex of 12S and 16S toxins. 12S toxin consists of a neurotoxin and a nontoxic non-HA (NTNH). The 16S toxin consists of a neurotoxin, an NTNH, and a hemagglutinin (HA). Food-borne botulism is caused by these complex toxins, which are ingested orally and absorbed from the digestive tract across the epithelial barrier lining the gut. Here we show that the type B 16S toxin, but not the 12S toxin or the neurotoxin, binds to the T84 human intestinal epithelial cell line. We also demonstrate that the HA moiety in the 16S toxin mediates the toxin binding to the cells. The carbohydrates containing a galactose moiety inhibited the binding of the 16S toxin to the T84 cells, and neuraminidase treatment of the cells increased the 16S toxin binding. The binding of the 16S toxin to the neuraminidase-treated cells was also inhibited by carbohydrates containing a galactose moiety. These results suggest that the type B 16S toxin binds to human intestinal epithelial cells via the galactose moiety in the carbohydrate chain on the cell surface

Activation of epidermal growth factor receptor signaling by the prostaglandin E2 receptor EP4 pathway during gastric tumorigenesis

金沢大学がん進展制御研究所Cyclooxygenase-2 (COX-2) plays an important role in tumorigenesis through prostaglandin E2 (PGE2) biosynthesis. It has been shown by in vitro studies that PGE2 signaling transactivates epidermal growth factor receptor (EGFR) through an intracellular mechanism. However, the mechanisms underlying PGE2-induced EGFR activation in in vivo tumors are still not fully understood. We previously constructed transgenic mice that develop gastric tumors caused by oncogenic activation and PGE2 pathway induction. Importantly, expression of EGFR ligands, epiregulin, amphiregulin, heparin-binding EGF-like growth factor, and betacellulin, as well as a disintegrin and metalloproteinases (ADAMs), ADAM8, ADAM9, ADAM10, and ADAM17 were significantly increased in the mouse gastric tumors in a PGE2 pathway-dependent manner. These ADAMs can activate EGFR by ectodomain shedding of EGFR ligands. Notably, the extensive induction of EGFR ligands and ADAMs was suppressed by inhibition of the PGE2 receptor EP4. Moreover, EP4 signaling induced expression of amphiregulin and epiregulin in activated macrophages, whereas EP4 pathway was required for basal expression of epiregulin in gastric epithelial cells. In contrast, ADAMs were not induced directly by PGE2 in these cells, suggesting indirect mechanism possibly through PGE2-associated inflammatory responses. These results suggest that PGE2 signaling through EP4 activates EGFR in gastric tumors through global induction of EGFR ligands and ADAMs in several cell types either by direct or indirect mechanism. Importantly, gastric tumorigenesis of the transgenic mice was significantly suppressed by combination treatment with EGFR and COX-2 inhibitors. Therefore, it is possible that inhibition of both COX-2/PGE2 and EGFR pathways represents an effective strategy for preventing gastric cancer. © 2011 Japanese Cancer Association

12-core x 3-mode Dense Space Division Multiplexed Transmission over 40 km Employing Multi-carrier Signals with Parallel MIMO Equalization

We demonstrate dense SDM transmission of 20-WDM multi-carrier PDM-32QAM signals over a 40-km 12-core x 3-mode fiber with 247.9-b/s/Hz spectral efficiency. Parallel MIMO equalization enables 21-ns DMD compensation with 61 TDE taps per subcarrier

Prostaglandin E2 signaling and bacterial infection recruit tumor-promoting macrophages to mouse gastric tumors

金沢大学がん研究所Background & Aims Helicobacter pylori infection induces an inflammatory response, which can contribute to gastric tumorigenesis. Induction of cyclooxygenase-2 (COX-2) results in production of prostaglandin E2 (PGE2), which mediates inflammation. We investigated the roles of bacterial infection and PGE2 signaling in gastric tumorigenesis in mice. Methods We generated a germfree (GF) colony of K19-Wnt1/C2mE mice (Gan mice); these mice develop gastric cancer. We examined tumor phenotypes, expression of cytokines and chemokines, and recruitment of macrophages. We also investigated PGE2 signaling through the PGE2 receptor subtype 4 (EP4) in Gan mice given specific inhibitors. Results Gan mice raised in a specific pathogen-free facility developed large gastric tumors, whereas gastric tumorigenesis was significantly suppressed in GF-Gan mice; reconstitution of commensal flora or infection with Helicobacter felis induced gastric tumor development in these mice. Macrophage infiltration was significantly suppressed in the stomachs of GF-Gan mice. Gan mice given an EP4 inhibitor had decreased expression of cytokines and chemokines. PGE2 signaling and bacterial infection or stimulation with lipopolysaccharide induced expression of the chemokine C-C motif ligand 2 (CCL2) (which attracts macrophage) in tumor stromal cells or cultured macrophages, respectively. CCL2 inhibition suppressed macrophage infiltration in tumors, and depletion of macrophages from the tumors of Gan mice led to signs of tumor regression. Wnt signaling was suppressed in the tumors of GF-Gan and Gan mice given injections of tumor necrosis factor-α neutralizing antibody. Conclusions Bacterial infection and PGE2 signaling are required for gastric tumorigenesis in mice; they cooperate to up-regulate CCL2, which recruits macrophage to gastric tumors. Macrophage-derived tumor necrosis factor-α promotes Wnt signaling in epithelial cells, which contributes to gastric tumorigenesis. © 2011 AGA Institute

Draft Genome Sequencing and Comparative Analysis of Aspergillus sojae NBRC4239

We conducted genome sequencing of the filamentous fungus Aspergillus sojae NBRC4239 isolated from the koji used to prepare Japanese soy sauce. We used the 454 pyrosequencing technology and investigated the genome with respect to enzymes and secondary metabolites in comparison with other Aspergilli sequenced. Assembly of 454 reads generated a non-redundant sequence of 39.5-Mb possessing 13 033 putative genes and 65 scaffolds composed of 557 contigs. Of the 2847 open reading frames with Pfam domain scores of >150 found in A. sojae NBRC4239, 81.7% had a high degree of similarity with the genes of A. oryzae. Comparative analysis identified serine carboxypeptidase and aspartic protease genes unique to A. sojae NBRC4239. While A. oryzae possessed three copies of α-amyalse gene, A. sojae NBRC4239 possessed only a single copy. Comparison of 56 gene clusters for secondary metabolites between A. sojae NBRC4239 and A. oryzae revealed that 24 clusters were conserved, whereas 32 clusters differed between them that included a deletion of 18 508 bp containing mfs1, mao1, dmaT, and pks-nrps for the cyclopiazonic acid (CPA) biosynthesis, explaining the no productivity of CPA in A. sojae. The A. sojae NBRC4239 genome data will be useful to characterize functional features of the koji moulds used in Japanese industries