Peritoneal injection of fucoidan suppresses the increase of plasma IgE induced by OVA-sensitization

We previously reported that fucoidan, a dietary fiber purified from seaweed, inhibited IgE production by B cells in vitro. In this study, we examined the effect of fucoidan on IgE production in vivo. The OVA-induced increase of plasma IgE was significantly suppressed when fucoidan was intraperitoneally, but not orally, administered prior to the first immunization with OVA. The production of IL-4 and IFN-γ in response to OVA in spleen cells isolated from OVA-sensitized mice treated with fucoidan in vivo was lower than that from mice treated without fucoidan. Moreover, the flow cytometric analysis and ELISpot assay revealed that the administration of fucoidan suppressed a number of IgE-expressing and IgE-secreting B cells, respectively. These results indicate that fucoidan inhibits the increase of plasma IgE through the suppression of IgE-producing B cell population, and the effect of fucoidan in vivo is crucially dependent on the route and timing of its administration.     

Newly developed waist actigraphy and its sleep/wake scoring algorithm

The purpose of this study was to formulate an algorithm for assessing sleep/waking from activity intensities measured with a waist-worn actigraphy, the Lifecorder PLUS (LC; Suzuken Co. Ltd., Nagoya, Japan), and to test the validity of the algorithm. The study consisted of 31 healthy subjects (M/F = 20/11, mean age 31.7 years) who underwent one night of simultaneous measurement of activity intensity by LC and polysomnography (PSG). A sleep(S)/wake(W) scoring algorithm based on a linear model was determined through discriminant analysis of activity intensities measured by LC over a total of 235 h and 56 min and the corresponding PSG-based S/W data. The formulated S/W scoring algorithm was then used to score S/W during the monitoring epochs (2 min each, 7078 epochs in total) for each subject. The mean agreement rate with the corresponding PSG-based S/W data was 86.9%, with a mean sensitivity (sleep detection) of 89.4% and mean specificity (wakefulness detection) of 58.2%. The agreement rates for the individual stages of sleep were 60.6% for Stage 1, 89.3% for Stage 2, 99.2% for Stage 3 + 4, and 90.1% for Stage REM. These results demonstrate that sleep/wake activity in young to middle-aged healthy subjects can be assessed with a reliability comparable to that of conventional actigraphy through LC waist actigraphy and the optimal S/W scoring algorithm.

     

Role of multidrug resistance-associated protein 1 in the pathogenesis of allergic airway inflammation

Multidrug resistance-associated protein 1 (MRP1) is a cysteinyl leukotriene (CysLT) export pump expressed on mast cells. CysLTs are crucial mediators in allergic airway disease. However, biological significance of MRP1 in allergic airway inflammation has not yet been elucidated. In this study, we sensitized wild-type control mice (mrp1(+/+)) and MRP1-deficient mice (mrp1(-/-)) to ovalbumin (OVA) and challenged them with OVA by aerosol. Airway inflammation and goblet cell hyperplasia after OVA exposure were reduced in mrp1(-/-) mice compared with mrp1(+/+) mice. Furthermore, CysLT levels in bronchoalveolar lavage fluid (BALF) from OVA-exposed mrp1(-/-) mice were significantly lower than those from OVA-exposed mrp1(+/+) mice. Levels of OVA-specific IgE, IL-4, and IL-13 in BALF were also decreased in OVA-exposed mrp1(-/-) mice. IgE-mediated release of CysLTs from murine bone marrow-derived mast cells was markedly impaired by MRP1 deficiency. Our results indicate that MRP1 plays an important role in the development of allergic airway inflammation through regulation of IgE-mediated CysLT export from mast cells.     

Proliferation of the hyperthermophilic archaeon Pyrobaculum islandicum by cell fission

Pyrobaculum islandicum is a hyperthermophilic archaeon. P. islandicum cells have been suggested to multiply by constriction, budding and branching, as no septa were observed in cells by phase-contrast light microscopy. In this study, we observed the cells using transmission electron microscopy, scanning electron microscopy, and light microscopy with dark-field image analyses, and we report binary fission via septum formation to be the main mode of P. islandicum’s proliferation. “Long cells” reported previously were found to comprise several cylindrical cells that align in tandem.     

MEKK4 signaling regulates filamin expression and neuronal migration

Periventricular heterotopia (PVH) is a congenital malformation of human cerebral cortex frequently associated with Filamin-A (FLN-A) mutations but the pathogenetic mechanisms remain unclear. Here, we show that the MEKK4 (MAP3K4) pathway is involved in Fln-A regulation and PVH formation. MEKK4(-/-) mice developed PVH associated with breaches in the neuroependymal lining which were largely comprised of neurons that failed to reach the cortical plate. RNA interference (RNAi) targeting MEKK4 also impaired neuronal migration. Expression of Fln was elevated in MEKK4(-/-) forebrain, most notably near sites of failed neuronal migration. Importantly, recombinant MKK4 protein precipitated a complex containing MEKK4 and Fln-A, and MKK4 mediated signaling between MEKK4 and Fln-A, suggesting that MKK4 may bridge these molecules during development. Finally, we showed that wild-type FLN-A overexpression inhibited neuronal migration. Collectively, our results demonstrate a link between MEKK4 and Fln-A that impacts neuronal migration initiation and provides insight into the pathogenesis of human PVH.     

Interaction of indole derivatives and tryptophan peptides with interfaces of sodium dodecyl sulfate micelles.

The free energies of transfer for indole and tryptophan derivatives and pentapeptides having single tryptophan residues from aqueous to sodium dodecyl sulfate (SDS) micellar phases have been systematically studied using the conventional method of ultraviolet absorption spectrophotometry. The free energies for the position isomers of methyl indoles varied depending on the substitution positions. Thus, the contribution of the methyl group to the binding affinity of the 4-methyl indole to the micelle was about twice that of the 2- and 7-methyl indoles. The free energy changes with the introduction of halogen groups to the indole rings were correlated to the nonpolar water-accessible surface area (DeltaA(np)) of the halogen moieties, which were regarded as hydrophobic. The relationships followed straight lines passing through the origins. Position dependence having tendencies similar to the methyl indoles was observed among the magnitudes of the slopes of the straight lines. These results strongly suggest that the indole rings of the derivatives residing in the micellar interface regions direct their imino moieties --NH-- toward the micellar surfaces. Experiments using model tryptophan pentapeptides showed that the magnitude of free energy change per methylene unit of an alkyl amino acid residue in the pentapeptide increased with elongation of the alkyl moiety and was not a constant value as reported for various alkyl compounds. When the peptides distribute to the SDS micelles, the peptide backbones are anchored in aqueous phases and the amino acid side chains in the interfaces extend their alkyl groups toward the micellar centers. Thus, the free energy changes can be connected to the positions of the alkyl groups of the amino acid residues in the micelles.     

Biochemical characterization of a novel cycloisomaltooligosaccharide glucanotransferase from Paenibacillus sp. 598K

Cycloisomaltooligosaccharide glucanotransferase (CITase; EC 2.4.1.248), a member of the glycoside hydrolase family 66 (GH66), catalyzes the intramolecular transglucosylation of dextran to produce cycloisomaltooligosaccharides (CIs; cyclodextrans) of varying lengths. Eight CI-producing bacteria have been found; however, CITase from Bacillus circulans T-3040 (CITase-T3040) is the only CI-producing enzyme that has been characterized to date. In this study, we report the gene cloning, enzyme characterization, and analysis of essential Asp and Glu residues of a novel CITase from Paenibacillus sp. 598K (CITase-598K). The cit genes from T-3040 and 598K strains were expressed recombinantly, and the properties of Escherichia coli recombinant enzymes were compared. The two CITases exhibited high primary amino acid sequence identity (67%). The major product of CITase-598K was cycloisomaltoheptaose (CI-7), whereas that of CITase-T3040 was cycloisomaltooctaose (CI-8). Some of the properties of CITase-598K are more favorable for practical use compared with CITase-T3040, i.e., the thermal stability for CITase-598K (≤50°C) was 10°C higher than that for CITase-T3040 (≤40°C); the k(cat)/K(M) value of CITase-598K was approximately two times higher (32.2s(-1)mM(-1)) than that of CITase-T3040 (17.8s(-1)mM(-1)). Isomaltotetraose was the smallest substrate for both CITases. When isomaltoheptaose or smaller substrates were used, a lag time was observed before the intramolecular transglucosylation reaction began. As substrate length increased, the lag time shortened. Catalytically important residues of CITase-598K were predicted to be Asp144, Asp269, and Glu341. These findings will serve as a basis for understanding the reaction mechanism and substrate recognition of GH66 enzymes.     

Heme Oxygenase-1 Promotes Survival of Renal Cancer Cells through Modulation of Apoptosis- and Autophagy-regulating Molecules

The cytoprotective enzyme heme oxygenase-1 (HO-1) is often overexpressed in different types of cancers and promotes cancer progression. We have recently shown that the Ras-Raf-ERK pathway induces HO-1 to promote survival of renal cancer cells. Here, we examined the possible mechanisms underlying HO-1-mediated cell survival. Considering the growing evidence about the significance of apoptosis and autophagy in cancer, we tried to investigate how HO-1 controls these events to regulate survival of cancer cells. Rapamycin (RAPA) and sorafenib, two commonly used drugs for renal cancer treatment, were found to induce HO-1 expression in renal cancer cells Caki-1 and 786-O; and the apoptotic effect of these drugs was markedly enhanced upon HO-1 knockdown. Overexpression of HO-1 protected the cells from RAPA- and sorafenib-induced apoptosis and also averted drug-mediated inhibition of cell proliferation. HO-1 induced the expression of anti-apoptotic Bcl-xL and decreased the expression of autophagic proteins Beclin-1 and LC3B-II; while knockdown of HO-1 down-regulated Bcl-xL and markedly increased LC3B-II. Moreover, HO-1 promoted the association of Beclin-1 with Bcl-xL and Rubicon, a novel negative regulator of autophagy. Drug-induced dissociation of Beclin-1 from Rubicon and the induction of autophagy were also inhibited by HO-1. Together, our data signify that HO-1 is up-regulated in renal cancer cells as a survival strategy against chemotherapeutic drugs and promotes growth of tumor cells by inhibiting both apoptosis and autophagy. Thus, application of chemotherapeutic drugs along with HO-1 inhibitor may elevate therapeutic efficiency by reducing the cytoprotective effects of HO-1 and by simultaneous induction of both apoptosis and autophagy.