Sustained Effect of Hyaluronic Acid in Subcutaneous Administration to the Cochlear Spiral Ganglion

The spatiotemporal distribution of drugs in the inner ear cannot be precisely evaluated because of its small area and complex structure. In the present study, we used hyaluronic acid (HA)-dispersed luciferin to image transgenic mice and to determine the effect of HA on controlled drug delivery to the cochlea. GFAP-luc mice, which express luciferase in cochlear spiral ganglion cells, were subcutaneously administered HA-luciferin (HA-sc) or luciferin dissolved in saline (NS-sc) or intraperitoneally administered luciferin dissolved in saline (NS-ip). The bioluminescence of luciferin was monitored in vivo in real time. The peak time and half-life of fluorescence emission were significantly increased in HA-sc-treated mice compared with those in NS-sc- and NS-ip-treated mice; however, significant differences were not observed in peak photon counts. We detected differences in the pharmacokinetics of luciferin in the inner ear, including its sustained release, in the presence of HA. The results indicate the clinical potential of using HA for controlled drug delivery to the cochlea.     

Properties and Transglycosylation Reaction of a Chitinase from Nocardia orientalis

The hydrolytic products of a chitinase purified from Nocardia orientalis were examined on reduced (GIcNAc)_n(n = 2~6). The rate of hydrolysis on reduced (GlcNAc)₄^₆ increased with increasing chain-length of A-acetylglucosamine residues, but the enzyme did not act on reduced (G1cNAc)₂ or reduced (GlcNAc)₃. Based on the analysis of the frequency distribution of bond cleavage on PNP-(GIcNAc)?(n = 2 ~ 5) in the initial hydrolysis, the enzyme was shown to release predominantly (G1cNAc)₂ from the nonreducing end of each substrate. The enzyme, which is essentially a hydrolase, also catalyzed a transglycosylation reaction in an excess of (GlcNAc)₄ as an initial substrate. In this case, the addition of ammonium sulfate to the reaction system resulted in a significant increase in (G1cNAc)₆ production. The yield of the hexasaccharide was about 34% of the chitinase-catalyzed net decrease of (GlcNAc)₄. The rate of the transglycosylation in the presence of ammonium sulfate greatly depended on the salt concentration, the temperature, and the substrate concentration.     

Isolation of Sporogen-AO1, a Sporogenic Substance,from Aspergillus oryzae

Sericin is a highly hydrophilic protein family acting as the glue in Bombyx mori silk. In order to apply sericin as a wound dressing, a novel sericin film named gel film was prepared by a simple process without using any chemical modifications: sericin solution was gelled with ethanol into a sheet shape and then dried. Infrared analysis revealed that the sericin gel film contained water-stable β-sheet networks formed in the gelation step. This structural feature rendered the gel film morphologically stable against swelling and gave it good handling properties in the wet state. The sericin gel film rapidly absorbed water, equilibrating at a water content of about 80%, and exhibited elastic deformation up to a strain of about 25% in the wet state. A culture of mouse fibroblasts on the gel film indicated that it had low cell adhesion properties and no cytotoxicity. These characteristics of sericin gel film suggest its potential as a wound dressing.     

Analysis of knockout mice suggests a role for VGF in the control of fat storage and energy expenditure

Background  

Previous studies of mixed background mice have demonstrated that targeted deletion of Vgf produces a lean, hypermetabolic mouse that is resistant to diet-, lesion-, and genetically-induced obesity. To investigate potential mechanism(s) and site(s) of action of VGF, a neuronal and endocrine secreted protein and neuropeptide precursor, we further analyzed the metabolic phenotypes of two independent VGF knockout lines on C57Bl6 backgrounds.     

A laminin-pepsin fragment with cell attachment and neurite outgrowth activity at distinct sites

Laminin is a large basement membrane glycoprotein which influences the behavior and morphology of a variety of cells. We have found that laminin and a pepsin fragment of laminin (P-lam) contain distinct sites for HT-1080 human fibrosarcoma cell attachment and for neurite outgrowth activity of PC12 and NG108-15 cell lines. Reduction and alkylation of laminin and P-lam fragment disulfide bonds, in the absence of denaturing agents, markedly reduced the cell attachment activity without reducing the neurite outgrowth response. The P-lam fragment (approximately 375 kDa) was found to contain part of the cross region of laminin and a portion of the long arm, on the basis of recognition by antisera against laminin synthetic peptides and fusion proteins. Modification of arginine residues by cyclohexanedione also had no effect on neurite outgrowth but reduced HT-1080 cell adhesion. Modification of lysine residues by succinic and citraconic anhydride, however, abolished laminin neurite outgrowth but not cell attachment activity. Neurite outgrowth activity was recovered by reversing the lysine modification. These data support the existence on laminin of separate sites for cell attachment and for neurite outgrowth.     

Generation of Brain Microvascular Endothelial-Like Cells from Human Induced Pluripotent Stem Cells by Co-Culture with C6 Glioma Cells

The blood brain barrier (BBB) is formed by brain microvascular endothelial cells (BMECs) and tightly regulates the transport of molecules from blood to neural tissues. In vitro BBB models from human pluripotent stem cell (PSCs)-derived BMECs would be useful not only for the research on the BBB development and function but also for drug-screening for neurological diseases. However, little is known about the differentiation of human PSCs to BMECs. In the present study, human induced PSCs (iPSCs) were differentiated into endothelial cells (ECs), and further maturated to BMECs. Interestingly, C6 rat glioma cell-conditioned medium (C6CM), in addition to C6 co-culture, induced the differentiation of human iPSC-derived ECs (iPS-ECs) to BMEC-like cells, increase in the trans-endothelial electrical resistance, decreased in the dextran transport and up-regulation of gene expression of tight junction molecules in human iPS-ECs. Moreover, Wnt inhibitors attenuated the effects of C6CM. In summary, we have established a simple protocol of the generation of BMEC-like cells from human iPSCs, and have demonstrated that differentiation of iPS-ECs to BMEC-like cells is induced by C6CM-derived signals, including canonical Wnt signals.     

The Tissue Fibrinolytic System Contributes to the Induction of Macrophage Function and CCL3 during Bone Repair in Mice

Macrophages play crucial roles in repair process of various tissues. However, the details in the role of macrophages during bone repair still remains unknown. Herein, we examined the contribution of the tissue fibrinolytic system to the macrophage functions in bone repair after femoral bone defect by using male mice deficient in plasminogen (Plg ^–/–), urokinase-type plasminogen activator (uPA ^–/–) or tissue-type plasminogen activator (tPA ^–/–) genes and their wild-type littermates. Bone repair of the femur was delayed in uPA ^–/– mice until day 6, compared with wild-type (uPA ^+/+) mice. Number of Osterix-positive cells and vessel formation were decreased in uPA ^–/– mice at the bone injury site on day 4, compared with those in uPA ^+/+ mice. Number of macrophages and their phagocytosis at the bone injury site were reduced in uPA ^–/– and Plg ^–/–, but not in tPA ^–/– mice on day 4. Although uPA or plasminogen deficiency did not affect the levels of cytokines, including TNF-α, IL-1β, IL-6, IL-4 and IFN-γ mRNA in the damaged femur, the elevation in CCL3 mRNA levels was suppressed in uPA ^–/– and Plg ^–/–, but not in tPA ^–/– mice. Neutralization of CCL3 antagonized macrophage recruitment to the site of bone injury and delayed bone repair in uPA ^+/+, but not in uPA ^–/– mice. Our results provide novel evidence that the tissue fibrinolytic system contributes to the induction of macrophage recruitment and CCL3 at the bone injury site, thereby, leading to the enhancement of the repair process.     

Synergistic Proinflammatory Responses by IL-17A and Toll-Like Receptor 3 in Human Airway Epithelial Cells

Viral respiratory infections activate the innate immune response in the airway epithelium through Toll-like receptors (TLRs) and induce airway inflammation, which causes acute exacerbation of asthma. Although increases in IL-17A expression were observed in the airway of severe asthma patients, the interaction between IL-17A and TLR activation in airway epithelium remains poorly understood. In this study, we demonstrated that IL-17A and polyI:C, the ligand of TLR3, synergistically induced the expression of proinflammatory cytokines and chemokines (G-CSF, IL-8, CXCL1, CXCL5, IL-1F9), but not type I interferon (IFN-α1, -β) in primary culture of normal human bronchial epithelial cells. Synergistic induction after co-stimulation with IL-17A and polyI:C was observed from 2 to 24 hours after stimulation. Treatment with cycloheximide or actinomycin D had no effect, suggesting that the synergistic induction occurred without de novo protein synthesis or mRNA stabilization. Inhibition of the TLR3, TLR/TIR-domain-containing adaptor-inducing interferon β (TRIF), NF-κB, and IRF3 pathways decreased the polyI:C- and IL-17A/polyI:C-induced G-CSF and IL-8 mRNA expression. Comparing the levels of mRNA induction between co-treatment with IL-17A/polyI:C and treatment with polyI:C alone, blocking the of NF-κB pathway significantly attenuated the observed synergism. In western blotting analysis, activation of both NF-κB and IRF3 was observed in treatment with polyI:C and co-treatment with IL-17A/polyI:C; moreover, co-treatment with IL-17A/polyI:C augmented IκB-α phosphorylation as compared to polyI:C treatment alone. Collectively, these findings indicate that IL-17A and TLR3 activation cooperate to induce proinflammatory responses in the airway epithelium via TLR3/TRIF-mediated NF-κB/IRF3 activation, and that enhanced activation of the NF-κB pathway plays an essential role in synergistic induction after co-treatment with IL-17A and polyI:C in vitro.     

BIG3 Inhibits the Estrogen-Dependent Nuclear Translocation of PHB2 via Multiple Karyopherin-Alpha Proteins in Breast Cancer Cells

We recently reported that brefeldin A-inhibited guanine nucleotide-exchange protein 3 (BIG3) binds Prohibitin 2 (PHB2) in cytoplasm, thereby causing a loss of function of the PHB2 tumor suppressor in the nuclei of breast cancer cells. However, little is known regarding the mechanism by which BIG3 inhibits the nuclear translocation of PHB2 into breast cancer cells. Here, we report that BIG3 blocks the estrogen (E2)-dependent nuclear import of PHB2 via the karyopherin alpha (KPNA) family in breast cancer cells. We found that overexpressed PHB2 interacted with KPNA1, KPNA5, and KPNA6, thereby leading to the E2-dependent translocation of PHB2 into the nuclei of breast cancer cells. More importantly, knockdown of each endogenous KPNA by siRNA caused a significant inhibition of E2-dependent translocation of PHB2 in BIG3-depleted breast cancer cells, thereby enhancing activation of estrogen receptor alpha (ERα). These data indicated that BIG3 may block the KPNAs (KPNA1, KPNA5, and KPNA6) binding region(s) of PHB2, thereby leading to inhibition of KPNAs-mediated PHB2 nuclear translocation in the presence of E2 in breast cancer cells. Understanding this regulation of PHB2 nuclear import may provide therapeutic strategies for controlling E2/ERα signals in breast cancer cells.