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Exendin-4 (Exenatide), a long-acting agonist of the glucagon-like peptide 1 receptor (GLP-1R), has been confirmed to protect the cardiovascular system from atherosclerosis in type 2 diabetes. However, the detailed mechanism of this process is not clear. Activation of endothelial nitric oxide synthase (eNOS) to produce nitric oxide (NO) plays an important role in endothelial homeostasis. Previous study shows that HDL activates eNOS via its receptor scavenger receptor type B class I (SR-BI). In this study, we checked the effect of exendin-4 on HDL/SR-BI-mediated eNOS activation in HUVECs. Firstly, we demonstrated the expression of GLP-1R in HUVECs and exendin-4 significantly induced HDL-mediated eNOS activation. Next, we found exendin-4 increased the expression and promoter activity of SR-BI, and then blocking of PKA or AMPK by its specific inhibitor cancelled this effect. Consistently, cAMP enhanced SR-BI promoter activity while domain negative AMPK inhibited the effect of exendin-4 on SR-BI promoter activity. Blocking of GLP-1R by exendin 9-39 cancelled exendin-4-induced SR-BI promoter activity and AMPK phosphorylation. As a downstream of AMPK, a transcription factor FoxO1 was confirmed to directly bind to the SR-BI promoter region by Chromatin Immunoprecipitation (ChIP) assay and overexpression of FoxO1 enhanced SR-BI promoter activity. Moreover, exendin-4 markedly increased the expression and nuclear recruitment of FoxO1 by decreasing its phosphorylation. As well as, mutation of FoxO1-binding site in the SR-BI promoter region or silence of FoxO1 cancelled exendin-4-induced SR-BI expression. In summary, our results show that exendin-4 upregulates the expression and transcription of SR-BI via PKA/AMPK/FoxO1 pathway, which contributes to HDL-mediated eNOS activation and NO generation in human endothelial cells. Disclosure J. Lyu: None. H. Imachi: None. K. Fukunaga: None. S. Sato: None. T. Dong: None. T. Ibata: None. T. Kobayashi: None. M. Matsumoto: None. K. Murao: None.

Campylobacter jejuni causes foodborne disease associated with abdominal pain, gastroenteritis, and diarrhea. These symptoms are induced by bacterial adherence and invasion of host epithelial cells. C. jejuni infection can occur with a low infective dose, suggesting that C. jejuni may have evolved strategies to cope with the bacterial clearance system in the gastrointestinal tract. The mucosa layer is the first line of defense against bacteria. Mucus conditions are maintained by water and anion (especially Cl(-)) movement. Cystic fibrosis transmembrane conductance regulator (CFTR) is the main Cl(-) channel transporting Cl(-) to the lumen. Mutations in CFTR result in dehydrated secreted mucus and bacterial accumulation in the lungs, and recent studies suggest that closely related pathogenic bacteria also may survive in the intestine. However, the relationship between C. jejuni infection and CFTR has been little studied. Here, we used an (125)I(-) efflux assay and measurement of short-circuit current to measure Cl(-) secretion in C. jejuni-infected T-84 human intestinal epithelial cells. The basic state of Cl(-) secretion was unchanged by C. jejuni infection, but CFTR activator was observed to induce Cl(-) secretion suppressed in C. jejuni-infected T-84 cells. The suppression of activated Cl(-) secretion was bacterial dose-dependent and duration-dependent. A similar result was observed during infection with other C. jejuni strains. The mechanism of suppression may occur by affecting water movement or mucus condition in the intestinal tract. A failure of mucus barrier function may promote bacterial adhesion or invasion of host intestinal epithelial cells, thereby causing bacterial preservation in the host intestinal tract.

An ethanologenic microorganism capable of fermenting all of the sugars released from lignocellulosic biomass through a saccharification process is essential for secondary bioethanol production. We therefore genetically engineered the ethanologenic bacterium Zymomonas mobilis such that it efficiently produced bioethanol from the hydrolysate of wood biomass containing glucose, mannose, and xylose as major sugar components. This was accomplished by introducing genes encoding mannose and xylose catabolic enzymes from Escherichia coli. Integration of E. coli manA into Z. mobilis chromosomal DNA conferred the ability to co-ferment mannose and glucose, producing 91 % of the theoretical yield of ethanol within 36 h. Then, by introducing a recombinant plasmid harboring the genes encoding E. coli xylA, xylB, tal, and tktA, we broadened the range of fermentable sugar substrates for Z. mobilis to include mannose and xylose as well as glucose. The resultant strain was able to ferment a mixture of 20 g/l glucose, 20 g/l mannose, and 20 g/l xylose as major sugar components of wood hydrolysate within 72 h, producing 89.8 % of the theoretical yield. The recombinant Z. mobilis also efficiently fermented actual acid hydrolysate prepared from cellulosic feedstock containing glucose, mannose, and xylose. Moreover, a reactor packed with the strain continuously produced ethanol from acid hydrolysate of wood biomass from coniferous trees for 10 days without accumulation of residual sugars. Ethanol productivity was at 10.27 g/l h at a dilution rate of 0.25 h(-1).

Adherence of diarrhea-associated Escherichia coli was studied by scanning electron microscopy. Enteropathogenic E. coli (EPEC) adherence factor-positive (EAF+) E. coli of EPEC serotypes (class I EPEC) adhered to plastic and human jejunal and ileal mucosa, similar to case and HeLa cells. Localized adherence, elongation of cell microvilli, and "locking" of the bacterial aggregates by the elongated microvilli were evident after incubation for 20 min. EAF+ E. coli adhered strikingly to mucus but rarely to M cells in Peyer's patch-associated epithelium. Most enteroaggregative E. coli (EAggEC) strains adhered to plastic, similar to HeLa cells. Some diffuse-adhering E. coli (DAEC) strains displayed no adherence to plastic but formed "dimples" on HeLa cells. Both EAggEC and DAEC adhered at lower levels to human small intestines (except M cells) than did EAF+ E. coli. In all cases of EAF+ E. coli, EAggEC, and DAEC, strains were found with atypical characteristics. The data demonstrate the unique adherence characteristics of EAF+ E. coli, EAggEC, and DAEC.