HIF-1α Dependent Upregulation of ZIP8, ZIP14, and TRPA1 Modify Intracellular Zn2+ Accumulation in Inflammatory Synoviocytes

Intracellular free zinc ([Zn²⁺]_i) is mobilized in neuronal and non-neuronal cells under physiological and/or pathophysiological conditions; therefore, [Zn²⁺]_i is a component of cellular signal transduction in biological systems. Although several transporters and ion channels that carry Zn²⁺ have been identified, proteins that are involved in Zn²⁺ supply into cells and their expression are poorly understood, particularly under inflammatory conditions. Here, we show that the expression of Zn²⁺ transporters ZIP8 and ZIP14 is increased via the activation of hypoxia-induced factor 1α (HIF-1α) in inflammation, leading to [Zn²⁺]_i accumulation, which intrinsically activates transient receptor potential ankyrin 1 (TRPA1) channel and elevates basal [Zn²⁺]_i. In human fibroblast-like synoviocytes (FLSs), treatment with inflammatory mediators, such as tumor necrosis factor-α (TNF-α) and interleukin-1α (IL-1α), evoked TRPA1-dependent intrinsic Ca²⁺ oscillations. Assays with fluorescent Zn²⁺ indicators revealed that the basal [Zn²⁺]_i concentration was significantly higher in TRPA1-expressing HEK cells and inflammatory FLSs. Moreover, TRPA1 activation induced an elevation of [Zn²⁺]_i level in the presence of 1 μM Zn²⁺ in inflammatory FLSs. Among the 17 out of 24 known Zn²⁺ transporters, FLSs that were treated with TNF-α and IL-1α exhibited a higher expression of ZIP8 and ZIP14. Their expression levels were augmented by transfection with an active component of nuclear factor-κB P65 and HIF-1α expression vectors, and they could be abolished by pretreatment with the HIF-1α inhibitor echinomycin (Echi). The functional expression of ZIP8 and ZIP14 in HEK cells significantly increased the basal [Zn²⁺]_i level. Taken together, Zn²⁺ carrier proteins, TRPA1, ZIP8, and ZIP14, induced under HIF-1α mediated inflammation can synergistically change [Zn²⁺]_i in inflammatory FLSs.     

A two-layered approach to communicative artifacts

A key issue in social intelligence design is the realization of artifacts that can fluently communicate with people. Thus, we proposed a two-layered approach to enhance a robot’s capacity of involvement and engagement. The upper layer flexibly controls social interaction by dynamic Bayesian networks (DBN) representing social interaction patterns. The lower layer improves the robustness of the system by detecting rhythmic and repetitive gestures. We designed a listener robot that can follow and record humans’ explanation on how to assemble and/or disassemble a bicycle. The implementation of this system is described by assembling the key algorithms presented in this paper.     

Synthesis and characterization of PEFC membranes based on fluorinated-polymer-alloy using pre-soft-EB grafting method

Polymer electrolyte fuel cell (PEFC) membranes based on thin film of crosslinked perfluorinated polymer-alloys (RX-FA) have been fabricated by soft electron beam (soft-EB) grafting with styrene monomers using soft-EB irradiation under nitrogen atmosphere at room temperature (RT). The characteristic properties of styrene-grafted materials (GRX-FA) and sulfonated materials (SRX-FA) have been measured by differential scanning calorimetry (DSC) and FT-IR spectroscopy, ionic conductivity and so on. The glass transition temperatures (dry state) of all obtained SRX-FA were about 105 ± 1 °C, which are higher than Nafion^®. The ion exchange capacities of SRX-FA have been achieved about 3.3 meq/g (dry). The ionic conductivity of obtained SRX-FA has showed about 0.17 S/cm at 60 °C with relative humidity (RH) of ∼95%. The ionic conductivities of the obtained SRX-FA were higher than that of conventional perfluoro-sulfonic acid membranes (PFSA). Fabricated membrane electrode assemblies (MEAs) based on the obtained SRX-FA have shown encouraging performance in the PEFC, compared with the conventional PFSA. The power density of obtained MEAs based on the SRX-FA was about 330-340 mW/cm² under 500 mA/cm² at 60 °C operation. Moreover, the maximum power densities of obtained MEAs based on the SRX-FA shows about 630 mW/cm² at 60 °C. On the other hand, the power density at 500 mA/cm² and maximum power density of MEA based on Nafion^®112 were about 320 and 590 mW/cm² at 60 °C. Thus, the power density of the obtained SRX-FA was higher than that of conventional PFSA.     

Possible role of dentin matrix in region-specific deposition of cellular and acellular extrinsic fibre cementum

The mechanism whereby a region-specific deposition of the two types of cementum (cellular cementum and acellular extrinsic fibre cementum) is regulated on the growing root surface was tested using bisphosphonate-affected teeth of young rats and guinea pigs. The animals were injected subcutaneously with 8 or 10 mg P x kg body weight(-1) x day(-1) of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) for 1 or 2 weeks. In rat molars, HEBP prevented mineralization of newly formed root dentin matrix and totally inhibited de novo deposition of acellular extrinsic fibre cementum. Instead, thick cellular cementum was induced on the non-mineralized root dentin surface, irrespective of the position of the root. In both animals, cellular cementum was also induced on the non-mineralized surface of root analogue dentin in HEBP-affected incisors, where only acellular extrinsic fibre cementum is deposited under normal conditions. In normal rat molars, dentin sialoprotein (DSP) was concentrated along the dentin-cellular cementum border, but not that of dentin and acellular extrinsic fibre cementum. In HEBP-affected rat incisors, DSP was shown to penetrate through the non-mineralized dentin into the surrounding tissues, but not through the mineralized portions. These data suggest that, at the site of cellular cementum formation, putative inducing factors for cellular cementum might diffuse into the periodontal space through the newly deposited mantle dentin matrix before it is mineralized. At earlier stages of root formation, mantle dentin might mineralize more promptly not to allow such diffusion. The timing of mineralization of mantle dentin matrix might be the key determinant of the types of the cementum deposited on the growing root surface.     

The microbial community in a 2,4-dinitrophenol-digesting reactor as revealed by 16S rDNA gene analysis

The microbial community of a 2,4-dinitrophenol-digesting reactor was investigated using different molecular biological techniques based on 16S rDNA gene sequences. A PCR-denaturing gradient gel electrophoresis (DGGE) analysis of the bacterial community in the reactor showed that one strong and five minor bands were observed in the DGGE profile. The results of excising and sequencing DGGE bands suggested that members of Rhodococcus, Nocardioides, and Nitrospira species were present in the reactor. Partial sequencing of cloned 16S rDNAs revealed diversity among the six main divisions--the alpha, delta subclasses of Proteobacteria, Nitrospira, Cytophagal Flexibacter/Bacteroides, Verrucomicrobia, and Actinobacteria--in the reactor. Two cloned sequence types were not closely affiliated with any described bacterial divisions. The isolation and phylogenetic analysis of 2,4-DNP-degrading bacteria from the reactor revealed that isolated strains were classified into two types of bacteria having different 16S rDNA sequences. One of these strain types was identified as a relative of Rhodococcus koreensis, and the other was identified as a relative of Nocardioides simplex FJ21-A.     

Combinational use of antibody affinities in an immunoassay for extension of dynamic range and detection of multiple analytes

Here, we describe the coordinated use of two antibodies with different affinities in a single immunoassay to extend the dynamic range and to enable detection of multiple analytes. The combination of dual antibodies was permitted with a flow-based assay at the antibody concentration below the dissociation constant, enabling affinity to govern the antibody-antigen binding. Both high and low affinity antibodies to estriol were used in combination to extend the range. The binding of each antibody was mutually independent and individually occurred over concentration ranges of 10 pM(-1) nM and 100 pM(-1) microM. The wide dynamic range of 10 pM(-1) microM was thus achieved as summation of the proportional signals to the total binding. When a combination of antibodies toward different antigens was used, it effectively detected multiple analytes within a mixture. In simultaneous analysis of a mixture of estradiol and estriol, the total signal was the sum of the binding signals from anti-estradiol and anti-estriol antibodies. In a further refinement, the individual antibodies were flowed through the flow cell sequentially, allowing the quantification of each binding signal within the combination. With this sequential format, measurement of the individual hormones in the range of 1.6 pM(-1) nM was shown. Furthermore, the same flow format was successfully applied to assay estriol and estradiol hormones in mixtures of six related compounds.     

Matrix metalloproteinase-2 inhibition and Zn2+-chelating activities of pyoverdine-type siderophores

Pyoverdine-type siderophores from fluorescent Pseudomonas species were purified by Zn2+-chelate chromatography, and their matrix metalloproteinase-2 (MMP-2) inhibition and metal-ion-chelating activities were studied. Structurally different pyoverdines showed different MMP-2 inhibition activities, and the inhibition activity was correlated with Zn2+-chelating activity. The IC50 value of a pyoverdine ((P113A1)-2, MW 1187) for MMP-2 was 0.27 microg/ml (0.23 microM).     

Examination of Surfactant Protein D as a Biomarker for Evaluating Pulmonary Toxicity of Nanomaterials in Rat

This work studies the relationship between lung inflammation caused by nanomaterials and surfactant protein D (SP-D) kinetics and investigates whether SP-D can be a biomarker of the pulmonary toxicity of nanomaterials. Nanomaterials of nickel oxide and cerium dioxide were classified as having high toxicity, nanomaterials of two types of titanium dioxides and zinc oxide were classified as having low toxicity, and rat biological samples obtained from 3 days to 6 months after intratracheal instillation of those nanomaterials and micron-particles of crystalline silica were used. There were different tendencies of increase between the high- and low-toxicity materials in the concentration of SP-D in bronchoalveolar-lavage fluid (BALF) and serum and in the expression of the SP-D gene in the lung tissue. An analysis of the receiver operating characteristics for the toxicity of the nanomaterials by SP-D in BALF and serum showed a high accuracy of discrimination from 1 week to 3 or 6 months after exposure. These data suggest that the differences in the expression of SP-D in BALF and serum depended on the level of lung inflammation caused by the nanomaterials and that SP-D can be biomarkers for evaluating the pulmonary toxicity of nanomaterials.     

Microstructure of high battery-performance Li2FeSiO4/C composite powder synthesized by combining different carbon sources in spray-freezing/freeze-drying process

Spray-freezing/freeze-drying technique was applied to the synthesis of Li₂FeSiO₄/C composite powders using solutions containing various carbon sources, water-soluble and colloidal carbon, followed by heat treatment. The effects of the carbon sources on the microstructure and battery performance of the synthesized composite powders were investigated. The microstructures of the composite powders were clearly different when different carbon sources were used, ascribed from the thermal behavior of the carbon sources during the heat treatment. It was possible to control the microstructures of Li₂FeSiO₄/C composite powders by combining different carbon sources, and the synthesized composite powders exhibited high discharge capacities by mixing with only a binder for cathode. The composite powders using glucose and Ketjenblack dispersion as carbon sources delivered 165 mAh/g at first discharge capacity at 0.1?C. The developed chain structure suitable for conducting paths in the electrodes and a higher-specific BET surface area, attributed from Ketjenblack, were likely responsible for the higher performance.