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The prostaglandin (PG) transporter SLCO2A1 regulates PGE

Anionic polymerization of methacrylate-functionalized ionic monomers, 2-(methacryloyloxy)ethyltrimethylammonium chloride (MTAC) and 3-(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonatopropanesulfonate...

Nafion is widely utilized as key polymer for proton electrolyte fuel cells owing to their high chemical, mechanical, and proton-conducting properties. The molecular aggregation state in Nafion films strongly affects the performance in the fuel cells. During operation process in fuel cells, peroxide derivatives such as H2O2 is generated and the chemical species deteriorates Nafion membrane, leading to a decreasing of performance of the fuel cells. The detail deterioration process including local structure, however, does not well-understand. In this work, we evaluate the local molecular aggregation state in deteriorated Nafion using microbeam wide X-ray diffraction (WAXD) measurements. Figure 1a shows WAXD line profile of before and after deterioration of Nafion membranes. The diffraction peaks were observed in ranging from 11 to 12 nm-1, which could be assigned to crystalline and amorphous structure in Nafion. The ratio of crystalline peak in deteriorated Nafion was more striking than that of initial Nafion membrane. This phenomenon might be explained following two mechanism. ① Polymer chains in amorphous domain were disconnected and were removed from the membrane. ② Polymer chains were disconnected and molecular motion of lower molecular weight is activated, leading to a formation of new crystalline domain caused by aggregation of lower molecular weight polymer chains. It is anticipated that above mechanisms occurs individually or at the same time. Though the dominant mechanism is still not clear, we can conclude that deterioration in Nafion starts from amorphous domain. To evaluate local molecular aggregation state in deteriorated Nafion, microbeams with size of 50 μm and 7 μm were utilized for WAXD measurements. Figure 1b and c show variation of ratio in crystalline domain as function of strain. The ratio of the crystalline domain in deteriorated Nafion was more striking than that of untreated Nafion. The ratio was constant when 50 μm beam was used, but not the case in 7 μm beam. This indicates that deterioration of Nafion membrane occurs 7 to 50 μm scale. The detail will be discussed in my presentation. Figure 1

The present work describes the preparation of host-guest complex formation-responsive liquid marbles (LMs) composed of a water droplet and hydrophobic adamantane (AD) powder. The importance of hydr...

Near-monodisperse, submicrometer-sized, colloidally stable polyacid particles containing phosphate groups were synthesized by free radical dispersion polymerization of acid phosphoxy polyoxyethylen...

Thermo-responsive polymer-coated polystyrene particles with a diameter of 84 µm (PNIPAM@PS) were prepared. The hydrophobicity of the surface of the PNIPAM@PS can be controlled by changing the tempe...

Near-monodispersed, colloidally stable, submicrometer-sized poly(acid phosphoxy ethyl methacrylate) (PAPEMA) latex particles were synthesized by free-radical dispersion polymerization using poly( N-vinylpyrrolidone) (PNVP) as both a steric colloidal stabilizer and a precipitating agent. Polymerization in the absence of PNVP led to a homogeneous transparent solution of PAPEMA, which indicates that the PNVP is essential for latex formation and the complex of PNVP and PAPEMA was formed during the dispersion polymerization. Dispersion copolymerizations with a divinyl cross-linking comonomer (∼20 wt % based on acid phosphoxy ethyl methacrylate) were also successful in synthesizing near-monodispersed, colloidally stable cross-linked PAPEMA latex particles, and the softness and p K

The aqueous oxidative coupling polymerization of 3,4-ethylenedioxythiophene was conducted in the presence of heptadecafluorooctane sulfonic acid, which was used as a perfluoroalkyl dopant to synthesize hydrophobic poly(3,4-ethylenedioxythiophene) particles. The poly(3,4-ethylenedioxythiophene) particles were characterized in terms of their size, morphology, surface and bulk chemical compositions, conductivity, hydrophilic–hydrophobic balance and (photo)thermal properties. The electron microscopy studies confirmed that poly(3,4-ethylenedioxythiophene) consisted of aggregates of primary atypical particles of a submicrometer size. X-ray photoelectron spectroscopy and the contact angle measurement indicated that the perfluoroalkyl dopants were present on the surface of the poly(3,4-ethylenedioxythiophene) particles, which caused them to have a hydrophobic character. The electrical conductivity of the pressed pellet was 15.5 S cm−1, which was one order of magnitude higher than that of the poly(3,4-ethylenedioxythiophene) that was synthesized in the absence of the perfluoroalkyl dopant. The dried poly(3,4-ethylenedioxythiophene) particles could be used as a near-infrared-responsive liquid marble stabilizer exhibiting light-to-heat conversion properties. The movement of the poly(3,4-ethylenedioxythiophene) particle-coated liquid marbles on a planar water surface was driven by near-infrared laser-induced Marangoni propulsion. The inner liquid could be released by the disruption of the liquid marbles via an application of an external stimulus. The aqueous oxidative coupling polymerization of 3,4-ethylenedioxythiophene was conducted in the presence of heptadecafluorooctane sulfonic acid, which was used as a perfluoroalkyl dopant to synthesize hydrophobic poly(3,4-ethylenedioxythiophene) particles. The dried poly(3,4-ethylenedioxythiophene) particles could be used as a near-infrared-responsive liquid marble stabilizer exhibiting light-to-heat conversion properties. The movement of the poly(3,4-ethylenedioxythiophene) particle-coated liquid marbles on a planar water surface was driven by near-infrared laser-induced Marangoni propulsion.

Solvent-free oxidative coupling polymerization of 3-hexylthiophene using FeCl3 oxidant was conducted to synthesize poly(3-hexylthiophene) grains. Optical and scanning electron microscopy studies confirmed production of submillimeter-sized atypical grains with rough surfaces. Solubility test, Fourier transform infrared spectroscopy, and 1H nuclear magnetic resonance studies indicated the branching and cross-linking of the poly(3-hexylthiophene). Elemental microanalysis and X-ray photoelectron spectroscopy studies confirmed that the poly(3-hexylthiophene) grains were doped with chloride ions. The poly(3-hexylthiophene) grains showed hydrophobic character due to hexyl side chains, and the critical surface tension was determined to be 25.9 mN m–1. The poly(3-hexylthiophene) showed a light-to-heat photothermal property, and near-infrared laser irradiation to the poly(3-hexylthiophene) grains induced a rapid temperature increase up to 664 °C. The poly(3-hexylthiophene) grains can work as an effective liquid mar...

Near-infrared (NIR) light irradiation induced the transformation of polypyrrole (PPy) to nitrogen-containing carbon (NCC) material due to its light-to-heat photothermal property. The temperature of the PPy increased over 700 °C within a few seconds by the NIR laser irradiation, and elemental microanalysis confirmed the decreases of hydrogen and chloride contents and increases of carbon and nitrogen contents. Monodispersed polystyrene (PS)-core/PPy shell particles (PS/PPy particles) synthesized by aqueous chemical oxidative seeded polymerization were utilized as a precursor toward monodispersed NCC capsules. When the NIR laser was irradiated to the PS/PPy particles, the temperature rose to approximately 300 °C and smoke was generated, indicating that the PS component forming the core was thermally decomposed and vaporized. Scanning electron microscopy studies revealed the successful formation of spherical and highly monodispersed capsules, and Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy studies confirmed the capsules consisted of NCC materials. Furthermore, sunlight was also demonstrated to work as a light source to fabricate NCC capsules. The size and thickness of the capsules can be controlled between 1 and 80 μm and 146 and 231 nm, respectively, by tuning the size of the original PS/PPy particles and PPy shell thickness.

Micrometer-sized hydrophobic polyaniline (PANI) grains were synthesized via an aqueous chemical oxidative polymerization protocol in the presence of dopant carrying perfluoroalkyl or alkyl groups. The critical surface tensions of the PANIs synthesized in the presence of heptadecafluorooctanesulfonic acid and sodium dodecyl sulfate dopants were lower than that of PANI synthesized in the absence of dopant, indicating the presence of hydrophobic dopant on the grain surfaces. The PANI grains could adsorb to air-liquid interfaces, and aqueous and nonaqueous liquid marbles (LMs) were successfully fabricated using liquids with surface tensions ranging between 72.8 and 42.9 mN/m. Thermography studies confirmed that the surface temperature of the LMs increased by near-infrared light irradiation thanks to the photothermal property of the PANI, and the maximum temperatures measured for nonaqueous LMs were higher than that measured for aqueous LM. We demonstrated that transport of the LMs on a planar water surface can be achieved via Marangoni flow generated by the near-infrared light-induced temperature gradient. Numerical analyses indicated that the LMs containing liquids with lower specific heat and thermal conductivity and higher density showed longer path length per one light irradiation shot and longer decay time. This is because generated heat could efficiently transfer from the LMs to the water surface and larger inertial force could work on the LMs. The LMs could also move over the solid substrate thanks to their near-spherical shapes. Furthermore, it was also demonstrated that the inner liquids of the LMs could be released on site by an external stimulus.

Polyhedral liquid marbles were fabricated using hydrophobic polymer plates in the shape of a circle, a heart and a star as a stabilizer and water as an inner liquid phase. Boxes could be fabricated by the evaporation of the inner water from the liquid marbles. The fabrication efficiency and stability of these boxes as a function of the plate shape were investigated. Functional materials such as polymers and colloidal particles were successfully introduced into the boxes., Boxes containing functional materials are fabricated from plate-stabilized liquid marbles via the evaporation of the inner liquid.

A liquid marble (LM) describes a liquid droplet that is wrapped by nonwetting micro- or nanoparticles and therefore obtains characteristics of a solid powder particle. Here, we investigate the effect of the stabilizing particle size on the resulting structure and properties of the LM. We synthesize a series of polystyrene particles with ultrathin coatings of heptadecafluorooctanesulfonic acid-doped polypyrrole with diameters ranging between 1 and 1000 μm by an aqueous chemical oxidative seeded polymerization of pyrrole. The methodology produced a set of hydrophobic particles with similar surface characteristics to allow the formation of LMs and to probe size effects in the LM formation and stabilization efficiency. We found that particles with a size above 20 μm adsorb as a particle monolayer to the surface of the LM, while smaller particles are adsorbed as ill-defined, multilayered aggregates. These results indicate that the balance between particle-particle interaction and gravity is an important parameter to control the surface structure of the LMs. The assembly behavior and size of the particles also correlated with the mechanical integrity of the LM against fall impact. The mechanical resistance was affected by the gap distance between the inner liquid of the LM and supporting substrate, the capillary forces acting between the particles at the LM surface, and the potential energy that depended on the particle size. Last, we demonstrate that the broadband light-absorbing properties of the polypyrrole shell also allow manipulating the evaporation rate of the inner liquid.

Solute carrier organic anion transporter family member 2A1 (SLCO2A1, also known as PGT, OATP2A1, PHOAR2, or SLC21A2) is a plasma membrane transporter consisting of 12 transmembrane domains. It is ubiquitously expressed in tissues, and mediates the membrane transport of prostaglandins (PGs, mainly PGE2, PGF2α, PGD2) and thromboxanes (e.g., TxB2). SLCO2A1-mediated transport is electrogenic and is facilitated by an outwardly directed gradient of lactate. PGs imported by SLCO2A1 are rapidly oxidized by cytoplasmic 15-hydroxyprostaglandin dehydrogenase (15-PGDH, encoded by HPGD). Accumulated evidence suggests that SLCO2A1 plays critical roles in many physiological processes in mammals, and it is considered a potential pharmacological target for diabetic foot ulcer treatment, antipyresis, and non-hormonal contraception. Furthermore, whole-exome analyses suggest that recessive inheritance of SLCO2A1 mutations is associated with two refractory diseases, primary hypertrophic osteoarthropathy (PHO) and chronic enteropathy associated with SLCO2A1 (CEAS). Intriguingly, SLCO2A1 is also a key component of the Maxi-Cl channel, which regulates fluxes of inorganic and organic anions, including ATP. Further study of the bimodal function of SLCO2A1 as a transporter and ion channel is expected to throw new light on the complex pathology of human diseases. Here, we review and summarize recent information on the molecular functions of SLCO2A1, and we discuss its pathophysiological significance.

We reported that bleomycin (BLM)-induced pulmonary fibrosis was exacerbated in the prostaglandin transporter gene (Slco2a1)-deficient mice (Slco2a1(-/-)). Because cigarette smoke (CS) contributes to creating a profibrotic milieu in the respiratory region, the present study aimed to investigate the impact of CS on SLCO2A1-associated pathogenesis in the lungs of BLM-instilled mice. Bronchoalveolar lavage (BAL) fluid cell analysis indicated more severe inflammation in Slco2a1(-/-) on day 5 after BLM intratracheal instillation, and Slco2a1 deletion increased mRNA expression of pro-inflammatory cytokines (Tnf-α and Il-1β) and chemokine (Ccl5) in BAL cells. Male Slco2a1(-/-) exhibited significantly higher amounts of released Il-1β in BAL fluid, compared with female Slco2a1(-/-), male or female Slco2a1(+/+) group. The amount of PGE2 collected in BAL fluid tended to increase in Slco2a1(-/-) compared with Slco2a1(+/+) group, whereas the PGE2 concentrations in lung tissues were comparable between both groups. Besides, PGE2 accumulated more in BAL fluid of male than that of female mice. Therefore, Slco2a1-deficient male mice were found to be more susceptible to BLM-treatment. Moreover, CS extracts (CSE) significantly reduced initial PGE2 uptake by rat type1 alveolar epithelial cell-like (AT1-L) cells and human SLCO2A1-transfected cells. Exposure of AT1-L cells to CSE resulted in decreased mRNA expression of Slco2a1, suggesting that CS modulates SLCO2A1 function. These results indicate that exacerbated lung inflammation is attributed to an increase in Il-1β peptide and PGE2 accumulation in the alveolar space, which exhibits a male predominance. SLCO2A1 inhibition by CSE is considered to be a new rationale for the lung toxicity of CS.

Loss-of-function mutations in the solute carrier organic anion transporter family, member 2a1 gene (SLCO2A1), which encodes a prostaglandin (PG) transporter, have been identified as causes of chronic nonspecific multiple ulcers in the small intestine; however, the underlying mechanisms have not been revealed. We, therefore, evaluated the effects of systemic knockout of Slco2a1 (Slco2a1−/−) and conditional knockout in intestinal epithelial cells (Slco2a1ΔIEC) and macrophages (Slco2a1ΔMP) in mice with dextran sodium sulphate (DSS)-induced acute colitis. Slco2a−/− mice were more susceptible to DSS-induced colitis than wild-type (WT) mice, but did not spontaneously develop enteritis or colitis. The nucleotide-binding domain, leucine-rich repeats containing family, pyrin domain-containing-3 (NLRP3) inflammasome was more strongly upregulated in colon tissues of Slco2a−/− mice administered DSS and in macrophages isolated from Slco2a1−/− mice than in the WT counterparts. Slco2a1ΔMP, but not Slco2a1ΔIEC mice, were more susceptible to DSS-induced colitis than WT mice, partly phenocopying Slco2a−/− mice. Concentrations of PGE2 in colon tissues and macrophages from Slco2a1−/− mice were significantly higher than those of WT mice. Blockade of inflammasome activation suppressed the exacerbation of colitis. These results indicated that Slco2a1-deficiency increases the PGE2 concentration, resulting in NLRP3 inflammasome activation in macrophages, thus exacerbating intestinal inflammation.

Near-monodispersed micrometer-sized polystyrene (PS) particles carrying amidino and carboxyl groups on their surfaces were synthesized by soap-free emulsion polymerization using an amphoteric free radical initiator. The resulting amphoteric PS particles were characterized in terms of diameter, morphology, disperibility in aqueous media and surface charge using scanning electron microscopy (SEM), optical microscopy (OM), sedimentation rate and electrophoretic measurements. At pH 2.0, where the amidino groups are protonated (positively charged), and at pH 11.0, where the carboxyl groups are deprotonated (negatively charged), the PS particles were well dispersed in aqueous media via electrostatic repulsion. At pH 4.8, where the surface charges are neutral, the PS particles were weakly aggregated. Furthermore, it was confirmed that the PS particles can function as a pH-sensitive foam stabilizer: foamability and foam stability were higher at pH 2.0 and 4.8, where the PS particles can be adsorbed to the air–water interface, and lower at pH 11.0, where the PS particles tend to disperse in bulk aqueous medium. SEM and OM studies indicated that hexagonally close-packed arrays of PS particles were formed on the bubble surfaces and moiré patterns were observed on the dried foams. Moreover, the fragments of dried foams showed iridescent character under white light.

Prostaglandin (PG) E2 is a well-established lipid mediator that plays a role in diverse functions and diseases of the brain. Cyclooxygenase and PGE synthase have been extensively studied as molecular determinants of extracellular concentration of PGE2 near prostanoid E receptors since the brain has limited capacity of PG metabolism. There is accumulating evidence that several members of the solute carrier (SLC) and ATP-binding cassette (ABC) superfamilies regulate PGE2 distribution in brain capillary endothelial cells, choroid plexus (CP) and arachnoid epithelium, and different parenchyma cells such as neuronal and glial cells. These transporters may mediate entry and exit of PGE2 at blood-brain and blood-cerebrospinal fluid boundaries, resulting in brain distribution of PGE2. However, their roles in neuroinflammation and disease progression remain unclear. In this review, current knowledge on transporters involved in brain distribution of PGE2 is summarized, and especially, potentials of organic anion transporting polypeptide (OATP) and organic anion transporter (OAT) family members are discussed as molecular determinants of PGE2 concentration in the brain.

Liquid marbles were prepared using a water droplet and nonprotonated hydrophobic poly(2

Electric, magnetic and resonance properties of La0·7Ba0·3MnO3/ZnO heterostructure fabricated on MgO (001) and LaAlO3 (100) substrates by ion-beam sputtering have been studied in the work. Good crystallinity and phase purity of all heterostructure components have been confirmed using X-ray diffraction. Phase separated magnetic state of the manganite layer of heterostructure has been experimentally proved in the temperature region from 300 K down to 3 K. It has been shown that (La,Ba)MnO3/ZnO bilayer exhibits multi-step resistive switching as voltage exceeds a certain temperature-dependent threshold value. Detailed study of the resistive switching processes has been carried out at room temperature and in the low-temperature region. It is concluded that phase-separated state of manganites is responsible for strong temperature-induced transformation of the features of resistive switching phenomena.

Hydrophobic and electrically conductive polyanilines were synthesized by single-step aqueous chemical oxidative polymerization in the presence of a perfluoroalkyl dopant, heptadecafluorooctane sulfonic acid. The resulting polyanilines were extensively characterized with respect to their morphology, surface/bulk chemical composition, wettability by water, (photo)thermal properties and conductivity. Scanning electron microscopy indicated that the polyanilines consisted of flocs of primary particles with sizes from submicrometer to a few hundreds of micrometers. Contact angle measurement and X-ray photoelectron spectroscopy confirmed the presence of perfluoroalkyl dopant on the surface of the dried polyanilines, which led to a water-repellent character. The conductivity of the pressed pellets increased from 3.2 × 10−3 S cm−1 to 1.4 S cm−1 as the dopant concentration used in the polymerization was increased, and the conductivities were higher than that of polyaniline synthesized in the absence of perfluoroalkyl dopant. The resulting polyaniline powder was able to function as a liquid marble stabilizer with photothermal properties. The liquid marble exhibited locomotion due to Marangoni propulsion on a planar water surface under irradiation with a near-infrared laser, and its transfer from water to solid surfaces was also achieved. The liquid marbles could be disrupted via an external stimulus to release their internal contents.

Aqueous dispersions of micrometer-sized, monodisperse polystyrene (PS) particles carrying pH-responsive poly[2-(diethylamino)ethyl methacrylate] (PDEA) colloidal stabilizer on their surfaces were dried under ambient conditions at pH 3.0 and 10.0. The resulting dried cake-like particulate materials were ground into powders and used as a stabilizer to fabricate liquid marbles (LMs) by rolling and electrostatic methods. The powder obtained from pH 3.0 aqueous dispersion consisted of polydisperse irregular-shaped colloidal crystal grains of densely packed colloids which had hydrophilic character. On the other hand, the powder obtained from pH 10.0 aqueous dispersion consisted of amorphous and disordered colloidal aggregate grains with random sizes and shapes, which had hydrophobic character. Reflecting the hydrophilic-hydrophobic balance of the dried PDEA-PS particle powders, stable LMs were fabricated with distilled water droplets by rolling on the powders prepared from pH 10.0, but the water droplets were adsorbed into the powders prepared from pH 3.0. In the electrostatic method, where an electric field assists transport of powders to a droplet surface, the PDEA-PS powders prepared from pH 3.0 jumped to an earthed pendant distilled water droplet to form a droplet of aqueous dispersion. Conversely the larger powder aggregates prepared from pH 10.0 did not jump due to cohesion between the hydrophobic PDEA chains on the PS particles, resulting in no LM formation.

In order to reinforce the composite consisting of isoprene rubber (IR) and calcium carbonate (CaCO3) particles, the surface treatment of CaCO3 particles with a mixture of amino- and mercapto-functi...

Poly(3,4-ethylenedioxythiophene) (PEDOT) grains were synthesized by solvent-free chemical oxidative polymerization in one-step and one-pot manner. The resulting PEDOT grains had atypical shapes wit...

In this study, oxidation-responsive liquid marbles (LMs) were prepared using ferrocene powder and water. Hydrophobic ferrocene powder in reduced state adsorbs to the water droplet surface to form L...

The aim of this study was to evaluate the effect of salinities on the nitrogen removal performance of a pilot-scale down-flow hanging sponge (DHS) reactor and an up-flow sludge blanket (USB) reactor which was installed in a closed recirculating aquaculture system for the purpose to maintain the water quality in the aquaculture tank. In this study, water quality and the growth of the Longtooth grouper, Epinephelus bruneus, were investigated at 30‰, 22.5‰, and 15‰ salinity for over 1000 days. The tested DHS reactor has successfully maintained total ammonium nitrogen in aquaculture tank at less than 1.0 mg-N·L−1 at various salinities. The abundance of nitrifying bacteria detected in the DHS reactor was higher at salinities of 15‰ and 22.5‰ than at 30‰. The USB reactors achieved a nitrate removal efficiency of over 60%. All fish survived all salinity conditions, exhibiting the highest daily weight gain of 2.0 ± 3.4 g-fish·day−1 at 15‰ salinity, which was 1.6 times higher than that at 30‰. The DHS-USB system could exert nitrogen removal under changing salinity conditions.

In this study, a photo-baffled reactor was operated to assess the performance of microalgal-nitrifying bacteria consortia in treating ammonia with its input concentration up to 180 mg-N·L−1. The six-compartment reactor, with a total effective volume of 3.2 L, was run continuously for 350 days at 30 °C. Overall, 66 ± 11% of ammonia was removed at a nitrogen loading rate of 0.083 ± 0.011 kg-N·m−3·day−1. In addition, long-term, stable partial nitrification was confirmed with nitrite concentration of 60 ± 26 mg-N·L−1 in effluent. On days 200 and 350, due to inhibition from the nitrite-oxidizing bacteria (NOB) activity, the dissolved oxygen and the free ammonia concentration was recorded as low as 0.3–0.7 mg·L−1 and 14–24 mg-N·L−1 in each column, respectively. The special configuration of the photo-baffled reactor created a competitive environment between Chlorella vulgaris and nitrifying bacteria. The microbial community structure of the retained sludge indicated that although detected at only 2–3% upstream, ammonia-oxidizing bacteria Nitrosomonas europaea increased downstream of the reactor. Meanwhile, the detection rate of NOB was less than 0.05% in each column and based on quantitative polymerase chain reaction analysis, NOB growth was inhibited. Therefore, these microalgae-nitrifying bacteria consortia have the potential to be a novel partial nitrification process for post-treatment using the anammox process.

To understand interaction of drugs with the prostaglandin transporter OATP2A1/SLCO2A1 that regulates disposition of prostaglandins, we explored the impact of 636 drugs in an FDA-approved drug library on 6-carboxyfluorescein (6-CF) uptake by OATP2A1-expressing HEK293 cells (HEK/2A1). Fifty-one and 10 drugs were found to inhibit and enhance 6-CF uptake by more than 50%, respectively. Effect of the 51 drugs on 6-CF uptake was positively correlated with that on PGE2 uptake (r = 0.64, p < 0.001). Among those, 5 drugs not structurally related to prostaglandins, suramin, pranlukast, zafirlukast, olmesartan medoxomil, and losartan potassium, exhibited more than 90% PGE2 uptake inhibition. Inhibitory affinity of suramin to OATP2A1 was the highest (IC50,2A1 of 0.17 μM), and its IC50 values to MRP4-mediated PGE2 transport (IC50,MRP4) and PGE2 synthesis in human U-937 cells treated with phorbol 12-myristate 13-acetate (IC50,Syn) were 73.6 and 336.7 times higher than IC50,2A1, respectively. Moreover, structure-activity relationship study in 29 nonsteroidal anti-inflammatory drugs contained in the library displayed inhibitory activities of anthranilic acid derivatives, but enhancing effects of propionic acid derivatives. These results demonstrate that suramin is a potent selective inhibitor of OATP2A1, providing a comprehensive information about drugs in clinical use that interact with OATP2A1.

Dry water is a free-flowing powder consisting of numerous solid particle-stabilized water droplets with typical sizes and volumes of 10−6–10−4 m and 10−3–103 pL, respectively. We describe the first characterization of dry water stabilized with hydrophobic silica nanoparticles, by using laser diffraction droplet size distribution analysis. The water droplet dimensions were measured to be a few tens of micrometers in air, by using the laser diffraction method. These dimensions correspond well with measurements by both laser diffraction and optical microscopy methods for a Pickering-type water-in-n-dodecane emulsion prepared by dispersing dry water in n-dodecane. Optical microscopy confirmed that the dry water consisted of flocs of non-spherical water droplets, and the flocs ranged in size from a few tens of micrometers to a few millimeters in air. On the basis of these results, the flocs of water droplets were proposed to dissociate into individual water droplets under the air blast during droplet size measurement by the laser diffraction method. It was also confirmed that pressurizing the dry water between two glass slides led to encapsulated water leaking from the silica nanoparticle shells. This on-demand pressure-sensitive water leak phenomenon shows a possible usage of the dry waters as a material delivery carrier.

Background Pilsicainide, classified as a relatively selective Na + channel blocker, also has an inhibitory action on the rapidly-activating delayed-rectifier K + current ( I Kr ) through human ether-a-go-go-related gene (hERG) channels. We studied the effects of chronic exposure to pilsicainide on the expression of wild-type (WT) hERG proteins and WT-hERG channel currents, as well as on the expression of mutant hERG proteins, in a heterologous expression system. Methods HEK293 cells stably expressing WT or mutant hERG proteins were subjected to Western blotting, immunofluorescence microscopy and patch-clamp experiments. Results Acute exposure to pilsicainide at 0.03–10μM influenced neither the expression of WT-hERG proteins nor WT-hERG channel currents. Chronic treatment with 0.03–10μM pilsicainide for 48h, however, increased the expression of WT-hERG proteins and channel currents in a concentration-dependent manner. Chronic treatment with 3μM pilsicainide for 48h delayed degradation of WT-hERG proteins and increased the channels expressed on the plasma membrane. A cell membrane-impermeant pilsicainide derivative did not influence the expression of WT-hERG, indicating that pilsicainide stabilized the protein inside the cell. Pilsicainide did not influence phosphorylation of Akt (protein kinase B) or expression of heat shock protein families such as HSF-1, hsp70 and hsp90. E4031, a chemical chaperone for hERG, abolished the pilsicainide effect on hERG. Chronic treatment with pilsicainide could also increase the protein expression of trafficking-defective mutant hERG, G601S and R752W. Conclusions Pilsicainide penetrates the plasma membrane, stabilizes WT-hERG proteins by acting as a chemical chaperone, and enhances WT-hERG channel currents. This mechanism could also be applicable to modulations of certain mutant-hERG proteins.

Particle-stabilized bubbles and foams have been observed and used in a wide range of industrial sectors and have been exploited as a technology platform for the production of advanced functional materials. The stability, structure, shape, and movement of these bubbles and foams can be controlled by external stimuli such as the pH, temperature, magnetic fields, ultrasonication, mechanical stress, surfactants, and organic solvents. Stimuli-responsive modes can be categorized into three classes: (i) bubbles/foams whose stability can be controlled by the adsorption/desorption/dissolution of solid particles to/from/at gas-liquid interfaces, (ii) bubbles/foams that can move, and (iii) bubbles/foams that can change their shapes and structures. The stimuli-responsive characteristics of bubbles and foams offer potential applications in the areas of controlled encapsulation, delivery, and release.

pH-Sensitive adsorption of polymer particles bearing poly[2-(dimethylamino)ethyl methacrylate] hairs at the air-water interface was investigated using a surface tensiometer, a Langmuir-Blodgett trough, and an X-ray reflectometer. We clarified that the particles are adsorbed at the interface at basic pH; by contrast, at acidic pH, only a small number of particles are adsorbed, whereas the majority are dispersed in the water phase. X-ray reflectometry analysis revealed that a particle monolayer was formed at the air-water interface, which was packed densely under increasing surface pressure, as determined by the electron density profile change. The contact angles of the particles at the air-water interface were estimated to be 29° and 34° at pH 3 and 10, respectively, by direct visualization of the air-water interface position of the particles using a polycyanoacrylate trapping method.