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Paclitaxel (PTX) is frequently utilized for the chemotherapy of breast cancer, but its continuous treatment provokes hyposensitivity. Here, we established a PTX-resistant variant of human breast cancer MCF7 cells and found that acquiring the chemoresistance elicits a remarkable up-regulation of aldo-keto reductase (AKR) 1C3. MCF7 cell sensitivity to PTX toxicity was increased by pretreatment with AKR1C3 inhibitor and knockdown of this enzyme, and decreased by its overexpression, inferring a crucial role of AKR1C3 in the development of PTX resistance. The PTX-resistant cells were much less sensitive to 4-hydroxy-2-nonenal and acrolein, cytotoxic reactive aldehydes derived from ROS-mediated lipid peroxidation, compared with the parental cells. Additionally, the resistant cells lowered levels of 4-hydroxy-2-nonenal formed during PTX treatment, which was mitigated by pretreating with AKR1C3 inhibitor, suggesting that AKR1C3 procures the chemoresistance through facilitating the metabolism of the cytotoxic aldehyde. The gain of PTX resistance additively promoted the aberrant expression of an ATP-binding cassette (ABC) transporter ABCB1 among the ABC transporter isoforms. The combined treatment with AKR1C3 and ABCB1 inhibitors overcame the PTX resistance and cross-resistance to another taxane-based drug docetaxel. Collectively, combined treatment with AKR1C3 and ABCB1 inhibitors may exert an overcoming effect of PTX resistance in breast cancer.

Abuse of pyrrolidinophenone derivatives (PPs) is known to cause severe damage to the central nervous system due to their high lipophilicity. In this study, we compared sensitivity to toxicity elicited by 4'-iodo-α-pyrrolidinononanophenone (I-α-PNP), one of the most potent cytotoxic derivatives among PPs synthesized previously, between SH-SY5Y cells differentiated by all-trans-retinoic acid (ATRA) and the undifferentiated cells, and found that the differentiated cells are more sensitive to I-α-PNP toxicity than the undifferentiated cells. Treatment with I-α-PNP elicited some apoptotic alterations (Bax expression, loss of mitrochondrial membrane potential, and activation of caspases) in the differentiated cells, whose patterns were similar to those in the undifferentiated cells. I-α-PNP treatment resulted in no significant alteration in Bcl-2 expression in the undifferentiated cells, whereas it considerably downregulated the protein expression in the differentiated cells, suggesting that the high I-α-PNP sensitivity of the differentiated cells is mainly due to downregulation of Bcl-2 expression. I-α-PNP treatment decreased nitric oxide (NO) production and neuronal NOS (nNOS) expression in the differentiated cells, and the patterns of I-α-PNP-evoked alterations in phosphorylation of cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) expression were almost the same as that in nNOS expression. Additionally, the addition of an NO donor restored the I-α-PNP-evoked alterations in expressions of Bcl-2, BDNF, and nNOS in the differentiated cells. These findings suggest that the downregulation of Bcl-2 expression by I-α-PNP in differentiated cells is attributed to the acceleration of two negative feedback loops (nNOS/NO/CREB loop and CREB/BDNF loop) triggered by decreased NO production.

In this study, we newly synthesized four α-pyrrolidinononanophenone (α-PNP) derivatives [4'-halogenated derivatives and α-pyrrolidinodecanophenone (α-PDP)], and then performed the structure-cytotoxicity relationship analyses. The results showed the rank order for the cytotoxic effects, α-PNPα-PDP4'-fluoro-α-PNP4'-chrolo-α-PNP4'-bromo-α-PNP4'-iodo-α-PNP (I-α-PNP), and suggest that cytotoxicities of 4'-halogenated derivatives were more intensive than that of elongation of the hydrocarbon chain (α-PDP). We also surveyed the apoptotic mechanism of I-α-PNP in brain microvascular endothelial (HBME) cells that are utilized as the in vitro model of the blood-brain barrier. HBME cell treatment with I-α-PNP facilitated the apoptotic events (caspase-3 activation, externalization of phosphatidylserine, and DNA fragmentation), which were almost completely abolished by pretreating with antioxidants. In addition, the immunofluorescent staining revealed the enhanced production of hydroxyl radical in mitochondria by the I-α-PNP treatment, inferring that the I-α-PNP treatment triggers the apoptotic mechanism dependent on the enhanced ROS production in mitochondria. The treatment with I-α-PNP increased the production of cytotoxic aldehyde 4-hydroxy-2-nonenal and decreased the amount of reduced glutathione. Additionally, the treatment decreased the 26S proteasome-based proteolytic activities and aggresome formation. These results suggest that decrease in the antioxidant properties is also ascribable to HBME cell apoptosis elicited by I-α-PNP.

Cisplatin (CDDP) is widely prescribed for the treatment of various cancers including bladder cancers, whereas its clinical use for breast cancer chemotherapy is restricted owing to easy acquisition of the chemoresistance. Here, we established a highly CDDP-resistant variant of human breast cancer MCF7 cells and found that procuring the resistance aberrantly elevates the expression of aldo-keto reductase (AKR) 1C3. Additionally, MCF7 cell sensitivity to CDDP was decreased and increased by overexpression and knockdown, respectively, of AKR1C3, clearly inferring that the enzyme plays a crucial role in acquiring the CDDP resistance. The CDDP-resistant cells suppressed the formation of cytotoxic reactive aldehydes by CDDP treatment, and the suppressive effects were almost completely abolished by pretreating with AKR1C3 inhibitor. The resistant cells also exhibited the elevated glutathione amount and 26S proteasomal proteolytic activities, and their CDDP sensitivity was significantly augmented by pretreatment with an inhibitor of glutathione synthesis or proteasomal proteolysis. Moreover, the combined treatment with inhibitors of AKR1C3, glutathione synthesis and/or proteasomal proteolysis potently overcame the CDDP resistance and docetaxel cross-resistance. Taken together, our results suggest that the combination of inhibitors of AKR1C3, glutathione synthesis and/or proteasomal proteolysis is effective as an adjuvant therapy to enhance CDDP sensitivity of breast cancer cells.

Claudin-2 (CLDN2), a component of tight junctions, is abnormally expressed in human lung adenocarcinoma tissue. CLDN2 contributes to chemoresistance in human lung adenocarcinoma-derived A549 cells, and it may be a target for cancer therapy. Here, we found that coffee ingredients, namely caffeine and theobromine, decreased the protein level of CLDN2 in human lung adenocarcinoma-derived A549 cells. In contrast, other components, such as theophylline and chlorogenic acid, had no effect. These results indicate that the 7-methyl group in methylxanthines may play a key role in the reduction in CLDN2 expression. The caffeine-induced reduction in the CLDN2 protein was inhibited by chloroquine, a lysosome inhibitor. In a protein-stability assay using cycloheximide, CLDN2 protein levels decreased faster in caffeine-treated cells than in vehicle-treated cells. These results suggest that caffeine accelerates the lysosomal degradation of CLDN2. The accumulation and cytotoxicity of doxorubicin were dose-dependently increased, which was exaggerated by caffeine but not by theophylline in spheroids. Caffeine decreased nuclear factor-erythroid 2-related factor 2 (Nrf2) levels without affecting hypoxia-inducible factor-1α levels. Furthermore, caffeine decreased the expression of Nrf2-targeted genes. The effects of caffeine on CLDN2 expression and anticancer-drug-induced toxicity were also observed in lung adenocarcinoma RERF-LC-MS cells. We suggest that caffeine enhances doxorubicin-induced toxicity in A549 spheroids mediated by the reduction in CLDN2 and Nrf2 expression.

Honeycomb layered oxides constitute an emerging class of materials that show interesting physicochemical and electrochemical properties. However, the development of these materials is still limited. Here, we report the combined use of alkali atoms ($\rm Na$ and $\rm K$) to produce a mixed alkali honeycomb layered oxide material, namely, $\rm NaKNi_2TeO_6$. Via transmission electron microscopy measurements, we reveal the local atomic structural disorders characterised by aperiodic stacking and incoherency in the alternating arrangement of $\rm Na$ and $\rm K$ atoms. We also investigate the possibility of mixed electrochemical transport and storage of $\rm Na$ and $\rm K$ ions in $\rm NaKNi_2TeO_6$. In particular, we report an average discharge cell voltage of about $4\, \rm V$ and a specific capacity of around $80\, \rm mAh\, g^{-1}$ at low specific currents (i.e., $< 10\, \rm mA\, g^{-1}$) when a $\rm NaKNi_2TeO_6$-based positive electrode is combined with a room-temperature $\rm NaK$ liquid alloy negative electrode using an ionic liquid-based electrolyte solution. These results represent a step towards the use of tailored cathode active materials for dendrite-free electrochemical energy storage systems exploiting room-temperature liquid alkali metal alloy materials., 39 Pages, 7 Figures, 1 Cover Art

Prostate cancer is known to have a relatively good prognosis, but long-term hormone therapy can lead to castration-resistant prostate cancer (CRPC). Cabazitaxel, a second-generation taxane, has been used for the CRPC treatment, but its tolerance is an urgent problem to be solved. In this study, to elucidate the acquisition mechanism of the cabazitaxel-resistance, we established cabazitaxel-resistant prostate cancer 22Rv1 (Cab-R) cells, which exhibited ∼sevenfold higher LD50 against cabazitaxel than the parental 22Rv1 cells. Cab-R cells showed marked increases in nuclear accumulation of NF-E2 related factor 2 (Nrf2) and expression of Nrf2-inducible antioxidant enzymes compared to 22Rv1 cells, suggesting that Nrf2 signalling is homeostatically activated in Cab-R cells. The cabazitaxel sensitivity of Cab-R cells was enhanced by silencing of Nrf2, and that of 22Rv1 cells was reduced by activation of Nrf2. Halofuginone (HF) has been recently identified as a potent Nrf2 synthetic inhibitor, and its treatment of Cab-R cells not only suppressed the Nrf2 signalling by decreasing both nuclear and cytosolic Nrf2 protein levels, but also significantly augmented the cabazitaxel sensitivity. Thus, inhibition of Nrf2 signalling may be effective in overcoming the cabazitaxel resistance in prostate cancer cells.

The ingested proteins are catabolized to di/tri-peptides and amino acids (AAs), which are absorbed through various transporters in the small intestinal and colonic epithelial cells. Tight junctions (TJs) are formed between neighboring cells and restrict paracellular fluxes to mineral ions and aqueous molecules. However, it is unknown whether the TJs are implicated in the control of paracellular fluxes to AAs. The paracellular permeability is controlled by claudins (CLDNs), which comprise a family of over 20 members. Here, we found that CLDN8 expression is decreased by AAs deprivation in normal mouse colon-derived MCE301 cells. The reporter activity of CLDN8 was not significantly changed by AAs deprivation, whereas the stability of CLDN8 protein was decreased. MicroRNA analysis showed that AAs deprivation increases the expression of miR-153-5p which targets CLDN8. The AAs deprivation-induced decline of CLDN8 expression was reversed by a miR-153-5p inhibitor. The CLDN8 silencing enhanced the paracellular fluxes to AAs, especially middle molecular size AAs. The expression levels of colonic CLDN8 and miR-153-5p in aged mice were lower and higher than those in young mice, respectively. We suggest that AAs deprivation downregulates CLDN8-dependent barrier function, mediated by the elevation of miR-153-5p expression in the colon, in order to enhance the AAs absorption.

New concepts for electrochemical energy storage devices are required to handle the physicochemical energy density limit that Li-ion batteries are approaching. All-solid-state fluoride-ion batteries (FIBs), in which monovalent fluoride anions are employed as charge carriers, are regarded as attractive options, and metallic Cu has been proved to be a promising cathode material. However, the rate capability is currently low and kinetic factors associated with the Cu/CuF2 reaction are not clearly understood, and the rate-determining step has not yet been identified. Herein, we present the kinetic analyses of a Cu thin-film cathode with a phase-boundary-controlled one-dimensional phase transition process via the Kolmogorov–Johnson–Mehl–Avrami equation. Concerning the capacity fading caused by the repeated volume expansion/contraction and the consequent interfacial contact loss, a Cu–Au alloy with a reduced lattice mismatch was designed and verified to be efficient to enable fast phase-transition kinetics along with stable cyclabilities, which opens new possibilities in cathode design for all-solid-state FIBs.

Autophagy inhibition is an attractive target for cancer therapy. In this study, we discovered inhibitors of Atg4B essential for autophagosome formation and evaluated their potential as therapeutics for prostate cancer. Seventeen compounds were identified as candidates after

α-Pyrrolidinononanophenone (α-PNP) is a highly lipophilic synthetic cathinone (SC) that possesses a long hydrocarbon chain. It is considered that abuse of α-PNP and its derivatives causes serious health hazards, but there has been little evidence to date on the toxicological, pharmacological and pharmacokinetic properties. The purpose of this study was to elucidate the structure–toxicity relationship and the mechanism of neurocytotoxicity of α-PNP derivatives. We synthesized three α-PNP derivatives [4′-fluoro, 4′-methoxy and 3′,4′-methylenedioxy substituents on the aromatic ring] and examined their toxicities against four human cells. The mechanism of 4′-fluoro-α-PNP (F-α-PNP)-induced neurocytotoxicity was investigated in terms of productions of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Cytotoxicites of α-PNP derivatives were augmented by the presence of 4′-fluoro or 3′,4′-methylenedioxy group on α-PNP, and F-α-PNP exhibited the most potent cytotoxicity. The F-α-PNP treatment resulted in ROS production, cytochrome-c release into cytosol, caspase-9 and caspase-3 activation and DNA fragmentation in neuronal SK-N-SH cells. In addition, subcellular fractionation analysis demonstrated that F-α-PNP is localized in the mitochondria as early as 12 h after the incubation. α-PNP derivatives increased level of nitric oxide (NO) and 3-nitrotyrosine adducts, indicative of peroxynitrite formation, in SK-N-SH cells. Pretreatment with a NO or peroxynitrite donor also exacerbated the cellular toxicity of F-α-PNP. The presence of 4′-fluoro or 3′,4′-methylenedioxy group in the aromatic ring on SCs likely elevates the risk of occurrence of health hazards. Additionally, enhanced production of ROS and RNS plays central roles in neuronal cell apoptotic mechanism of F-α-PNP.

Lithium-rich cathode materials show higher theoretical capacity than conventional cathode materials because the redox activity of oxide ions in addition to the transition metal valence change contr...

Little is known about antipsychotic prescription patterns among children and adolescents in Japan, particularly in outpatient settings. We investigated the prevalence and trends of antipsychotic prescription for outpatients aged ≤ 17 years receiving a first antipsychotic prescription from 2006 to 2012 based on a large-scale dispensation dataset. Measurements included age, sex, department of diagnosis and treatment, type of prescription (monotherapy or polytherapy), antipsychotic dosage, and concomitant psychotropic drugs. Of the 10,511 patients, 65.1% were aged 13-17 years, and 52.9% were males. Second-generation antipsychotic monotherapy prescriptions increased from 53.8% in 2006 to 78.3% in 2012. Risperidone was the most frequently prescribed antipsychotic, followed by aripiprazole and olanzapine. Approximately 25.0% of patients were prescribed an initial dose less than recommended. Second-generation antipsychotic monotherapy is currently the most frequent prescription pattern among outpatients aged ≤ 17 years receiving an initial antipsychotic prescription.

Most members of the aldo-keto reductase (AKR) 1 C subfamily are hydroxysteroid dehydrogenases (HSDs). Similarly to humans, four genes for AKR1C proteins (AKR1C1-AKR1C4) have been identified in the pig, which is a suitable species for biomedical research model of human diseases and optimal organ donor for xenotransplantation. Previous study suggested that, among the porcine AKR1Cs, AKR1C1 and AKR1C4 play important roles in steroid hormone metabolism in the reproductive tissues; however, their biological functions are still unknown. Herein, we report the biochemical properties of the two recombinant enzymes. Kinetic and product analyses of steroid specificity indicated that AKR1C1 is a multi-specific reductase, which acts as 3α-HSD for 3-keto-5β-dihydro-C

Eijitsu, the fruits of Rosa multiflora Thunberg, is a traditional Japanese natural medicine and used as purgatives. The active constituents were identified as flavonol glycosides, multiflorin A (MF), and multinoside A (MSA), but mechanism of the purgative action is still unknown. We hypothesized that the flavonol glycosides 1 and 2 may exhibit the purgative actions through modulating intestinal epithelial barrier function. Then, this study aimed to investigate their effects on intestinal epithelial barrier function and possible molecular mechanisms in human intestinal Caco-2 cells. MF and MSA decreased transepithelial electrical resistance and increased paracellular permeability of Caco-2 cell monolayers. Expression of claudins (CLDNs) involved in paracellular permeability of ions and low-molecular substances was significantly decreased by the treatment with MF or MSA. The compounds increased the ratio of N-cadherin/E-cadherin, expression of transforming growth factor-β and Slug, and phosphorylation level of Smad3, suggesting epithelial-mesenchymal transition activation, and epithelial-mesenchymal transition inhibition by transforming growth factor-β receptor kinase inhibitors completely recovered the decreased CLDNs expression caused by MF and MSA. Moreover, the increased paracellular permeability and the decreased CLDNs expression by the treatment with MF or MSA for 24 hours recovered to the same extent as the untreated group with the compounds by continuous culture in the growth medium alone for 48 hours. These results suggest that Eijitsu may be effective in preventing or relieving constipation symptoms, unless used chronically.

Once weak ultraviolet ray-B (UVB) irradiates the skin cells, the generation of reactive nitrogen species (RNS), but not reactive oxygen species (ROS), is stimulated for the mislocalization of claudin-1 (CLDN1), an essential protein for forming tight junctions (TJs). Since our skin is constantly exposed to sunlight throughout our lives, an effective protection strategy is needed to maintain the skin barrier against weak UVB. In the present study, we investigated whether an ethanol extract of Brazilian green propolis (EBGP) and flavonoids had a protective effect against weak UVB irradiation-induced barrier dysfunction in human keratinocyte-derived HaCaT cells. A pretreatment with EBGP suppressed TJ permeability, RNS production, and the nitration level of CLDN1 in the weak UVB-exposed cells. Among the propolis components, apigenin and apigenin-like flavonoids have potent protective effects against NO production and the mislocalization of CLDN1 induced by UVB. The analyses between structures and biological function revealed that the chemically and structurally characteristic flavonoids with a hydroxyl group at the 4′ position on the B-ring might contribute to its protective effect on barrier dysfunction caused by weak UVB irradiation. In conclusion, EBGP and its component apigenin protect HaCaT cells from weak UVB irradiation-induced TJ barrier dysfunction mediated by suppressing NO production.

Polymer electrolyte fuel cells (PEFCs) have been developed for electric device applications such as fuel cell vehicles (FCV). PEFC cathode catalyst requires an excess Pt due to the degradation of oxygen reduction reaction (ORR) activity. Many research efforts aim to design Pt-based nanomaterials with controllable composition and structure to increase their activity while reducing the amount of Pt, like core-shell structure. The core-shell structure is obtained by Adzic’s method (Cu-UPD)1, where the underpotential deposition (UPD) of Cu mediator on Pt and the displacement of Cu mediator by Pt are conducted. This method requires the highly precise potential control for the UPD of Cu by means of potentiostats. In contrast, our previous research demonstrated the spontaneous two-step method (Galvanic cell) to synthesize spherical Pd@Pt core-shell catalyst without a special control of electrochemical equipment and reducing/stabilizing agents2. In this study, this Galvanic cell method was applied for Pd@Pt core-shell nanowire catalysts. Compared with the conventional Cu-UPD method, this method can synthesize the catalysts on a larger scale and form more uniform monolayer Pt shells, resulting in a higher ORR activity. Ultrathin Pd nanowires were prepared using surfactants as templates3. Briefly, palladium nitrate, ODA, and DTAB were dissolved in toluene under strong magnetic stirring. The mixture was placed in an inert atmosphere and sonicated for 20 min. NaBH4 was added to the above solution as a reducing agent. One hour later, the organic phase was recovered using distilled water and chloroform as extractants. After centrifugation, Pd nanowires can be obtained. After mixing the catalyst with carbon, the Pd/C powder is dispersed in the N2-saturated 0.01M CuSO4 and 0.5 M H2SO4 solution, with continual stirring. Then, a Cu wire is immersed in the above mixture2. Near 5 hours later, Cu wire is extracted, and successively N2-saturated 10 mM K2PtCl4 solution is added to the suspension to obtain Pd-nanowire@Pt/C. Electrochemical tests were performed in 0.1 M HClO4, and the catalyst ORR activity was evaluated at 0.9 V. XAS measurements of Pt L-edge were also performed under the same conditions. In contrast to the previously reported method (Cu-UPD)4, our proposed method does not require electrochemical equipment, or reducers/stabilizers, and uniform Pt shells in Pd-nanowire@Pt/C can be obtained. As shown in Figure 1, Core-shell catalysts have a lower white line intensity than Pt/C, meaning that they are more difficult to oxidize. The ligand effect causes surface Pt compression, and after calculating, the first-shell Pt-Pt bond length in the Pd-NW@Pt Gal. catalyst is shorter than that of the nanoparticle, which means a stable structure and less oxygen species generation. So, the catalysts synthesized using the Galvanic Cells method can provide higher ORR activity (specific activities: 0.8 mA/cm2 and mass activities: 1.3 A/mgPt) compared to the Cu-UPD method. Acknowledgement This work was supported by the project (JPNP20003) and a NEDO FC-Platform project commissioned by the New Energy and Industrial Technology Development Organization (NEDO). References; [1] Zhang, J.; Mo, Y.; Vukmirovic M. B.; Klie R; Sasaki K.; Adzic R R.; J. Phys. Chem. B 2004 108 (30), 10955-10964. [2] Wang, X.; Orikasa, Y.; Inaba, M.; Uchimoto, Y.; et al. ACS Catal., 2020, 10, 430– 434. [3] Teng, X.; Han, W.; Ku, W.; Hucker, M.; et al. Angew. Chem., Int. Ed. 2008, 47, 2055– 2058. [4] Koenigsmann, C., Adzic, R. R.; et al. J. Am. Chem. Soc., 2011 , 133, 9783– 9795. Figure 1

Suntivich et al. found a volcano relationship between the eg occupancy in perovskite oxide and OER activity. eg filling of ~ 1.2 is the optimum value1. Nevertheless, some materials do not follow this trend. A typical example is oxides containing a high valence Ni(4+) state. To elucidate the effect of high-valence Ni on OER activity, it is necessary to evaluate the OER activity of materials with stable Ni in a high oxidation state (4+). However, in case of the perovskite family, the formation of Ni4+ requires calcination under high oxygen partial pressures (60-200 bar). In contrast, LiNi0.5Mn1.5O4 (LNMO) with a spinel structure is known that lithium ions are desorbed by oxidation to produce tetravalent nickel ions quantitatively. Therefore, by using this material as an oxygen-evolving electrode, it is possible to quantitatively evaluate the activity of tetravalent nickel ions. Herein, we report the OER activity of nickel-manganese spinel, in which Ni4+ was stable up to the bulk. LiNi0.5Mn1.5O4 powder was synthesized as follows. Stoichiometric amounts of LiNO3, Ni(NO3)2.6H2O, and Mn(NO3)2.6H2O were dissolved in ultrapure water. A four-to-five-fold molar excess of citric acid was added while stirring. This solution was heated at 400 °C to obtain the precursor. The obtained powder was calcined at 800 °C for 12 h and at 700 °C for 48 h under pure O2. Various levels of chemical delithiation were achieved by reacting LiNi0.5Mn1.5O4 with nitronium tetrafluoroborate in acetonitrile solution for 48 h at 25 ºC. The degree of delithiation was controlled by changing the ratio of LiNi0.5Mn1.5O4 to NO2BF4. The suspension of LiNi0.5Mn1.5O4 and NO2BF4 was stirred for 48 h to obtain a uniform particle composition. Subsequently, the suspension was filtered, thoroughly washed with acetonitrile at least three times, and dried overnight in a vacuum oven. Then, chemical composition was determined using inductively coupled plasma optical emission spectrometry, X-ray diffraction (XRD) patterns were collected in BL02B2 at SPring-8, Japan. XAS was conducted for Mn and Ni K-edges, XAS for Mn, Ni L-edges, and O K-edge was also conducted. This study focused on the electrocatalytic activity of LixNi0.5Mn1.5O4 spinels with different lithium contents. The lithium (x) content in LixNi0.49Mn1.51O4 was controlled by topochemical delithiation using NO2BF4 in an acetonitrile solution. Upon applying this approach, nickel changed from the divalent to tetravalent state, while the tetravalent state of manganese was maintained. The OER activity was found to increase with decreasing x. x = 0.00 showed the highest OER activity. The Tafel slopes indicated that the RDS changed from OH− adsorption to proton transfer from OH*; thus, the OER kinetics was enhanced. The XAS spectra of Ni and O indicated that the presence of Ni4+ caused a downshift in the unoccupied Ni 3d state and decreased the energy barrier of charge transfer from the oxygen intermediate species to the metal active site; hence, the OER activity was enhanced. This study revealed the mechanism underpinning the high OER activity of high-valence Ni(4+) and also provided a approach for the development of highly active catalyst materials, namely, topochemical delithiation. Acknowledgement This work is based on results obtained from a project (JPNP14021) commissioned by the New Energy and Industrial Technology Development Organization (NEDO) of Japan. References Suntivich, J.; May, K. J.; Gasteiger, H. A.; Goodenough, J. B.; Shao-Horn, Y., Science 2011, 334, 1383-1385. Ren Y. et al., ACS Appl. Energy Mater. 2021 4 (10), 10731-10738

Polymer electrolyte fuel cells (PEFCs) are clean energy devices with polymer electrolytes and are expected to play an important role in the development of a global renewable energy system and a pure hydrogen energy society in the future. PEFCs have already been applied for small-scale energy systems such as fuel cell vehicles (FCVs). Pt-based catalysts are basically used due to the relatively inefficient reaction kinetics and catalyst degradation under strong acidic conditions during the oxygen reduction reaction (ORR). However, there are still many difficulties in realizing acceptable cost-effective FCVs. It is known that the ORR activity of Pt-based catalysts is reduced by specific adsorption of anionic species. Perfluorosulfonic acid ionomers such as Nafion® are commonly included in the catalyst layers of PEFCs to provide protonic pathways for promoting the ORR1. However, direct observation of anion adsorption on practical Pt nanoparticle/C catalysts for perfluorosulfonic acid ionomers using X-ray absorption spectroscopy (XAS) still has less report. In this study, to achieve specific adsorption over a higher potential range that is at least equal to the ORR active potential (around 0.90 V vs. RHE), operando XAS measurements were performed; the electronic status and local structural change of Pt atoms induced by the specific adsorption of anions at any potential were observed2. Pt/C (29.1 wt.%; TEC10V30E) catalyst supported was purchased from TKK. Nafion® solution was employed to prepare Pt/C catalyst ink with I/C ranging from 0.0 to 1.0. And the amount of Pt/C was adjusted to form a 20 µgcarbon cm-2 catalyst layer after dropping 10 μL on a glassy carbon RDE. The electrochemical cell was constructed using a model electrode fabricated in the working electrode, a Pt mesh for the counter electrode, a reversible hydrogen electrode for the reference electrode, and 0.1 M HClO4 aq for the electrolyte. operando XAS measurement of Pt L-edge was carried out in SPring-8 (Japan). The specific activity decreased as the I/C ratio increased from 0.0 to 0.20. We utilized many methods to evaluate the adsorption species separately, including the measurements of ECSA and oxygen coverage, CO stripping voltammetry, operando X-ray absorption fine structure, and analysis of 5d orbital vacancy. The ECSA and oxygen coverage did not change with increasing ionomer content, indicating that the Pt/C catalyst activity was affected by other adsorption species. A comparison of the CO displacement charge and 5d orbital vacancies of the Pt/C catalysts with I/C = 0.0 and 1.0 suggests that the ionomer-specific adsorption increases when the I/C ratio of the Pt/C catalyst is 1.0; active sites on the surface of the Pt/C catalyst are occupied, resulting in lower catalyst activity. Acknowledgment This work was supported by the project (JPNP20003) and a NEDO FC-Platform project commissioned by the New Energy and Industrial Technology Development Organization (NEDO). References: [1] Subbaraman, R.; Strmcnik, D.; Markovic, N. M.; et al. J. Chem. Phys. Phys. Chem. 2010, 11, 13, 2825-2833. [2] Liu, C.; Uchiyama, T.; Uchimoto, Y.; et al. ACS Appl. Energy Mater. 2021, 4 (2), 1143-1149. Figure 1

Among the hydrogen-based energy conversion devices, the proton exchange membrane fuel cell (PEMFC) has shown some advantages in high conversion efficiency, no polluted gas generation, and low-temperature operation, which made it possible to be applied in many fields[1]. To date, Pt/C catalysts are still regarded as one the most promising catalysts for the PEMFC. However, for the real application of platinum, the activity will be influenced by the operation environment, like the specific adsorption of the sulfo group in the Nafion ionomer, which is critical to applying the Pt/C as practical electrocatalysts in PEMFC[2]. Recently, the two-dimensional material overlayers like nitrogen-doped carbon shells have shown the function to tune the electronic statement of the metal surface, which was considered to originate from the strong p-d coupling between the doped nitrogen and the platinum nanoparticles and could optimize the O binding energy to improve the activity[3]. In this research, the nitrogen-doped carbon-coated platinum (PTCN) was synthesized by facile thermal treatment from the polydopamine to carbon shells with tunable thickness. To measure the electronic statement change on the catalysts modified with Nafion ionomer during the oxygen reduction reaction (ORR), the Operando X-ray absorption spectroscopy (XAS) was applied at BL36XU in Spring-8. After being coated with the nitrogen-doped carbon shell, the specific activity of PTCN increased by 1.3 times higher than commercial Pt/C catalysts, which could be originated from the interaction between the nitrogen-doped carbon shell and the platinum surface atom. It could be identified by the changes after coated with a nitrogen-doped carbon shell from the X-ray photoelectron spectroscopy (XPS) and XAS N K-edge results. To explore the protective effect of nitrogen-doped carbon shell against the specific adsorption by Nafion ionomer, different amount of ionomer was modified onto the Pt/C and PTCN catalysts, of which the specific activity showed a 16 % decay on Pt/C, however, almost no changes on PTCN. To illustrate this protection effect, the CO displacement charge test was applied to quantitatively analyze the adsorbed species coverage on the platinum surface, and increased coverage of anion species was observed on the higher amount of ionomer additive for Pt/C, however, it showed slight changes on PTCN varying different ionomer content, which suggested the sulfo-group from ionomer could hardly be absorbed on the platinum surface after coated with nitrogen-doped carbon shell. Furthermore, since the CO will get oxidation on the platinum surface from 0.6 V (vs. RHE), the Operando XAS was applied to measure the electronic statement and structure changes during the reaction potential range (0.5 V – 1.1 V vs. RHE). It also showed less change on the 5d vacancy for PTCN. These results showed potential for using carbon-coated catalysts in solving the specific adsorption problem from Nafion ionomer and promoting the large-scale application for the PEMFCs. Figure 1. Influence of the I/C ratio on the specific activity of Pt/C and PTCN at 0.90 V vs RHE. Acknowledgement This work was supported by the project (JPNP20003) and a NEDO FC-Platform project commissioned by the New Energy and Industrial Technology Development Organization (NEDO). And China Scholarship Council (CSC) was acknowledged for the doctoral scholarship of Yunfei Gao (202006270046). Reference s : 1. Debe, M. K. Nature 2012, 486 (7401), 43-51. 2. Kodama, K.; Nagai, T.; Kuwaki, A.; Jinnouchi, R.; Morimoto, Y., Nature Nanotech . 2021, 16 (2), 140-147. 3. Gan, T.; Yang, J.; Morris, D.; Chu, X.; Zhang, P.; Zhang, W.; Zou, Y.; Yan, W.; Wei, S.-H.; Liu, G., Commun. 2021, 12 (1), 2741. Figure 1

For the widespread use of fuel cell vehicles, it is necessary to improve the performance and durability of the cathode catalyst of polymer electrolyte fuel cells (PEFCs). In particular, high-temperature operation of PEFCs is attracting attention for application to commercial vehicles for heavy-duty application. Operation at higher temperatures than the conventional one (60-80°C) is expected to enhance oxygen reduction kinetics and mass transfer and reduce specific adsorption of ionomers. Despite such advantages, due to the thermal effect, the oxide formation on Pt surface is expected to be enhanced and decrease the activity of the catalyst. However, the quantitative relationship between catalyst behavior and the electronic structure of Pt under high temperature operation has not yet been elucidated. Here, we developed an MEA cell for high temperature and high pressure conditions and analyzed the oxidation state and local structure of Pt on Pt/C catalysts at different temperatures by operando XAS measurements. MEAs were prepared with Pd/C as anode catalyst, Pt/C as cathode catalyst. XAS measurements of the Pt LIII absorption edge were made at 80°C, 105°C, and 120°C with 100% H2 flowing to the anode and Air flowing to the cathode, and spectra were collected by the transmission mode. The area values of the XANES spectra were calculated to compare the relationship of Pt oxide formation with operating temperature and the local structural model of Pt oxide at high temperature by EXAFS. Comparison of operando XANES results of cathode catalyst Pt/C under conventional operating temperature (80°C), 105°C, and 120°C showed a marked difference, especially at 80°C and 120°C. In addition, the XANES area values increased as the operating temperature was increased. This is thought to be due to the fact that Pt oxide formation is accelerated at higher temperatures. Next, comparing the EXAFS analysis results at each temperature, the Pt-O bond peak is stronger at 120°C, indicating that Pt oxidation is more advanced than at 80°C. The 120°C results can be explained by a mixed model of β-PtO2 and Pt metal. Pt-O bond coordination number analysis shows that β-PtO2, in which oxygen is latent inside Pt, is formed more frequently at high temperatures. From this result, it was found that the structure of Pt oxide is different in high-temperature systems, and that catalyst design must take this into account. Fig ure 1. Pt LIII-edge XANES spectra Area vs. Applied voltage for pure H2 at the cathode of Pt/C. MEA temperature: blue circle is 80°C, black circle is 105°C, red circle is 120°C. Fig ure 2. Pt LIII-edge EXAFS Pt-O bond coordination Number vs. Applied voltage for pure H2 at the cathode of Pt/C. MEA temperature: blue triangle is 80°C, black triangle is 105°C, red triangle is 120°C. Acknowledgement This work was supported by a NEDO FC-Platform project commissioned by the New Energy and Industrial Technology Development Organization (NEDO) Reference s : [1] Hideto I.; Koichi I.; Masashi M.; Yoshimi K.; Kazuo K.; Yasuhiko I., J . Am . Chem . Soc ., 2009, 131 (17), 6293-6300. Figure 1

Polymer electrolyte fuel cells (PEFCs) are attracting attention as an environmentally friendly electrochemical device that uses hydrogen as a fuel. The application of PEFC has been limited by the consumption of platinum due to the sluggish kinetics of the cathode reaction and limiting platinum reserves. It has been noted that the interaction between the cathode catalyst and the oxygen intermediate species results in an overpotential in the ORR process. Therefore, it is very important to evaluate the interaction between the oxygen species and the catalyst based on the electronic structure. Pt nanowires are known to be highly active as ORR catalysts because they tend to expose more active planes for ORR, such as (111) planes1. Pt oxides formed on Pt nanowires with such 1D anisotropy are different from conventional nanoparticle catalysts in terms of structure and electronic structure2. However, this has not been fully clarified yet under oxygen reduction conditions. In this study, we analyzed the oxidation state of Pt nanowire catalysts in the ORR by operando analysis and analyzed the electronic and local structures. Synthesis of Pt nanowire catalyst : Oleylamine (5 mL) was used as a solvent and Pt(acac)2, Ni(acac)2, W(CO)6 and CTAC (hexadecyltrimethylammonium chloride) were added and sonicated for 1 hour. The product was dissolved and allowed to react in an oil bath at 160°C for 2 hours. The product particles were collected by centrifugation, and the washing and centrifugation were repeated three times with a mixture of cyclohexane: ethanol = 1:9. The nanowires were then loaded on Vulcan XC-72. ORR activity evaluation and XAS measurement: The rotating disk electrode (RDE) method was used for electrochemical measurements. A tripolar cell was used for the measurements. catalyst ink containing Pt nanowires was prepared and applied to a glassy carbon electrode for the RDE to prepare the electrode. A catalyst-coated electrode was used as the working electrode, a platinum mesh as the counter electrode, and a reversible hydrogen electrode (RHE) as the reference electrode. The electrolyte was 0.1 M HClO4. The cell temperature was controlled at 25 oC. XAS measurements were performed using a home-made measuring cell and the same electrochemical measurement conditions as for the RDE. The morphology and structure of the prepared Pt nanowires were observed by electron microscopy. As shown in Figure 1, the nanowires were uniformly distributed on the carbon and no significant aggregation was observed. The average diameter of the nanowires was 2.0 nm.To analyze the local structure of the Pt nanowire catalyst, the Pt-Pt bond length was estimated from EXAFS. Figure 2 shows the fitting results of the Pt-Pt bond lengths of Pt nanowire and Pt nanoparticle (TEC10V30E, TKK) catalysts in the range 0.5-1.1 V vs. RHE. With increasing potential, the Pt-Pt bond lengths of both catalysts gradually increased, but the Pt nanowire catalyst maintained a short Pt-Pt bond, and this nanowire characteristic structure may be the reason for its higher ORR activity than the nanoparticle. Acknowledgements: This work was supported by the project (JPNP20003) and a NEDO FC-Platform project commissioned by the New Energy and Industrial Technology Development Organization (NEDO). References [1] Kim J. M. et al., Science Advances 2021, 7, (30), e1601705. [2] Zhaoyu Y. et al., Nano Letters 2021 21 (21), 9354-9360. Figure 1

Overuse of pyrrolidinophenones (PPs) is known to cause damage to vascular and central nervous systems, but little is known about its effect on brain endothelial barrier function. In this study, we found that exposure to 4'-iodo-α-pyrrolidinononanophenone (I-α-PNP), one of the most potently cytotoxic PPs, at sublethal concentrations decreases trans-endothelial electrical resistance and increases paracellular permeability across a monolayer of human brain microvascular endothelial cells. Treatment with I-α-PNP also elevated the production of superoxide anion. Furthermore, the treatment reduced the expression and plasma membrane localization of a tight junction protein claudin-5 (CLDN5), which was almost restored by pretreatment with an antioxidant N-acetyl-l-cysteine. These results indicate that I-α-PNP treatment may down-regulate the plasma membrane-localized CLDN5 by elevating the production of reactive oxygen species (ROS). The treatment with I-α-PNP increased the nuclear translocation of Forkhead box protein O1 (FoxO1), an oxidative stress-responsive transcription factor, and pretreating with a FoxO1 inhibitor ameliorated the decrease in CLDN5 mRNA. In addition, I-α-PNP treatment up-regulated the expression and secretion of matrix metalloproteinase-2 (MMP2) and MMP9, and the addition of an MMP inhibitor reversed the degradation of CLDN5 by I-α-PNP. Moreover, I-α-PNP treatment facilitated the activation of 26S proteasome-based proteolytic activity and pretreatment with an inhibitor of 26S proteasome, but not autophagy, suppressed the CLDN5 degradation by I-α-PNP. Accordingly, it is suggested that the down-regulation of CLDN5 by exposure to I-α-PNP is ascribable to suppression of the gene transcription due to FoxO1 nuclear translocation through ROS production and to acceleration both of the MMPs (MMP2 and MMP9)- and 26S proteasome-based proteolysis.

The aberrant expression of claudins (CLDNs), which are tight junctional proteins, is seen in various solid tumors, but the regulatory mechanisms and their pathophysiological role are not well understood. Both CLDN1 and CLDN11 were highly expressed in human lung squamous cell carcinoma (SCC). Chrysin, found in high concentration in honey and propolis, decreased CLDN1 and CLDN11 expression in RERF-LC-AI cells derived from human lung SCC. The phosphorylation level of Akt was decreased by chrysin, but those of ERK1/2 and c-Jun were not. LY-294002, an inhibitor of phosphatidylinositol 3-kinase, inhibited the phosphorylation of Akt and decreased the expression levels of CLDN1 and CLDN11. The association between phosphoinositide-dependent kinase 1 (PDK1) and Akt was inhibited by chrysin, but the phosphorylation of PDK1 was not. Immunoprecipitation and quartz-crystal microbalance assays revealed that biotinylated-chrysin binds directly to Akt. The knockdown of CLDN1 and CLDN11 using small interfering RNAs increased the transepithelial flux of doxorubicin (DXR), an anthracycline anticancer drug. Similarly, both chrysin and LY-294002 increased DXR flux. Neither CLDN1 knockdown, CLDN11 knockdown, nor chrysin changed the anticancer drug-induced cytotoxicity in a two-dimensional culture model, whereas they enhanced cytotoxicity in a spheroid culture model. Taken together, chrysin may bind to Akt and inhibit its phosphorylation, resulting in the elevation of anticancer drug-induced toxicity mediated by reductions in CLDN1 and CLDN11 expression in RERF-LC-AI cells. We suggest that chrysin may be useful as an adjuvant chemotherapy in lung SCC.

Warfarin is a drug used for anticoagulation management, with a narrow therapeutic range and multiple drug-drug interactions. Adherence and proper use of concomitant medication are thus fundamental to the efficacy and safety of warfarin therapy. In 2012, we retrospectively analyzed data from three large-scale pharmacy chains in Japan. We included all adults (≥ 20 years old) with at least one record of warfarin dispensation. We examined patient demographic data, adherence as measured by medication possession ratio (MPR), and co-dispensation focusing on the number of concomitant dispensations and concurrent use of medications that increase bleeding risk. Thresholds of underadherence and overadherence were set at0.9 and1.1, considering the narrow therapeutic window. We reviewed 443007 warfarin dispensation records of 71340 individuals (median age, 73 years; 62% male). The MPR was 1.0 (interquartile range: 0.96-1.0), and underadherence and overadherence was found in 16.3 and 1.9% of individuals, respectively. The median number of co-dispensed drugs was eight at each pharmacy encounter, which did not differ by age group. Drugs associated with a high bleeding risk were dispensed in 40.0% of encounters and accounted for 16.4% of all co-dispensed drugs. In summary, we found optimal overall adherence, as assessed by MPR, among our Japanese study population, even when defining a strict cut-off value. However, polypharmacy was common in all age groups and medications with a high bleeding risk profile were often co-dispensed with warfarin. Future research addressing how these dispensation patterns affect patient outcome is warranted.

Graphite is widely used as an anode material in almost all Lithium (Li)-ion batteries. Li is easily absorbed into the layer structure of graphite, forming lithium-carbon intercalation compounds LixC between LiC6 and C. However, although they are simple binary compounds, their structures have been left unelucidated for a long time, especially for the compounds between LiC12 and C. This is probably because the Li concentrations are too low to make a big difference in diffraction pattern between these Li-intercalated graphites and pure graphite. It has been known, however, that they have stacked layer structures, which strongly suggests that they are very likely to form modulated structures. Structural analyses of these compounds based on the modulated structure model were successfully performed, comprehensively elucidating all the LixC structures lying between LiC6 and C.

Abnormal expression of the tight junctional components claudins (CLDNs) is observed in various malignant tissues. We reported recently that CLDN18 expression is down-regulated in human lung adenocarcinoma tissues. In the present study, we investigated the biological functions of CLDN18 using lung adenocarcinoma A549 cells. Microarray analysis showed that CLDN18 increases zonula occludens (ZO)-2 expression in A549 cells. The ectopic expression of CLDN18 increased nuclear ZO-2 levels, which were inhibited by N-[2-[[3-(4-bromophenyl)-2-propen-1-yl]amino]ethyl]5-isoquinolinesulfonamide (H-89), a nonspecific protein kinase A (PKA) inhibitor, but not by a PKA inhibitor 14-22 amide. In addition, dibutyryl cyclic adenosine monophosphate, an analogue of PKA, did not increase ZO-2 levels. These results suggest that H-89 sensitive factors without PKA are involved in the CLDN18-induced elevation of ZO-2. The cell cycle was affected by neither ZO-2 knockdown in CLDN18-expresssing A549 (CLDN18/A549) cells nor ZO-2 overexpression in A549 cells, suggesting that ZO-2 does not play an important role in the regulation of cell proliferation. The introduction of ZO-2 small interfering RNA (siRNA) into CLDN18/A549 cells increased migration, the expression and activity of matrix metalloproteinase 2 (MMP2), and the reporter activity of an MMP2 promoter construct. Furthermore, H-89 enhanced both mRNA levels and reporter activity of MMP2 in CLDN18/A549 cells. These results suggested that a reduction in CLDN18-dependent ZO-2 expression enhances MMP2 expression in lung adenocarcinoma cells, resulting in the promotion of the cell migration. CLDN18 may be a novel marker for metastasis in lung adenocarcinoma.

Vanadium sulfide (VS4) is one of the promising positive electrode materials for next-generation rechargeable lithium-ion batteries because of its high theoretical capacity (1196 mA h g−1). Crystalline VS4 has a unique structure, in which the Peierls-distorted one-dimensional chains of V–V bonds along the c axis are loosely connected to each other through van der Waals interactions. In this study, an amorphous VS4 is prepared by mechanical milling of the crystalline material, and its lithiation/delithiation behavior is investigated by solid-state nuclear magnetic resonance (NMR) spectroscopy. The amorphous VS4 shows a chain structure similar to that of crystalline VS4. The amorphous host structure is found to change drastically during the lithiation process to form Li3VS4: the V ions become tetrahedrally coordinated by S ions, in which the valence states of V and S ions simultaneously change from V4+ to V5+ and S− to S2−, respectively. When the Li insertion proceeds further, the valence state of V ions is reduced. After the 1st cycle, the amorphous VS4 recovers to the chain-like structure although it is highly disordered. No conversion to elemental V is observed, and a high capacity of 700 mA h g−1 is reversibly delivered between 1.5 and 2.6 V.

Claudin-2 (CLDN2), a component of tight junction, is involved in the reduction of anticancer drug-induced toxicity in spheroids of A549 cells derived from human lung adenocarcinoma. Fisetin, a dietary flavonoid, inhibits cancer cell growth, but its effect on chemosensitivity in spheroids is unknown. Here, we found that fisetin (20 μM) decreases the protein level of CLDN2 to 22.3%. Therefore, the expression mechanisms were investigated by real-time polymerase chain reaction and Western blotting. Spheroids were formed in round-bottom plates, and anticancer drug-induced toxicity was measured by ATP content. Fisetin decreased the phosphorylated-Akt level, and CLDN2 expression was decreased by a phosphatidylinositol 3-kinase (PI3K) inhibitor, suggesting the inhibition of PI3K/Akt signal is involved in the reduction of CLDN2 expression. Hypoxia level, one of the hallmarks of tumor microenvironment, was reduced by fisetin. Although fisetin did not change hypoxia inducible factor-1α level, it decreased the protein level of nuclear factor erythroid 2-related factor 2, a stress response factor, by 25.4% in the spheroids. The toxicity of doxorubicin (20 μM) was enhanced by fisetin from 62.8% to 40.9%, which was rescued by CLDN2 overexpression (51.7%). These results suggest that fisetin can enhance anticancer drug toxicity in A549 spheroids mediated by the reduction of CLDN2 expression.

Sibutramine had been prescribed as an oral anorexiant that reduces dietary intake, but was withdrawn from the market due to frequent occurrence of severe cardiovascular events including hypertension. To elucidate the pathogenic mechanism of hypertension, we here investigated whether sibutramine facilitates damage and contraction of human aortic smooth muscle (HASM) cells or not. Treatment with sibutramine provoked HASM cell apoptosis, which was attributed to production of reactive oxygen species and mitochondria dysfunction. In addition, the drug treatment of the cell promoted calcium influx, phosphorylation of myosin light chain and contraction, which were abrogated by pretreating the cells with antioxidant and nitric oxide (NO) donor. Thus, the drug-evoked contraction is likely due to a preceding disturbance of balance between the drug-elicited reactive oxygen species production and exogenous NO supply. Compared to sibutramine, its N-desmethyl and N-didesmethyl metabolites exhibited much less toxicity and contraction against HASM cells, in which sibutramine was hardly demethylated. The low metabolic capacity of the cells may also be pertinent to the damage and contraction elicited by sibutramine. Taken together, our data suggest that sibutramine facilitates apoptosis and contraction of aortic smooth muscle cells through elevating production of reactive oxygen species and decreasing exogenous NO supply, leading to pathogenesis of hypertension.

Claudin-2 (CLDN2), a tight junctional protein, is involved in the chemoresistance in a three-dimensional spheroid culture model of human lung adenocarcinoma A549 cells. However, the mechanism has not been fully clarified. We found that the knockdown of CLDN2 expression by siRNA in the spheroid reduces the expression of glucose transporters and metabolic enzymes. In a two-dimensional culture model, the expression of these proteins was increased by glucose deprivation or fasentin, an inhibitor of glucose transporter. In addition, the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and antioxidant enzymes including heme oxygenase-1, NAD(P)H:quinone oxidoreductase-1, and a glutamate–cysteine ligase modifier subunit were increased by fasentin. The fluorescence intensities of JC-1, a probe of mitochondrial membrane potential, and MitoROS 580, a probe of mitochondrial superoxide production, were increased by fasentin. These results suggest that mitochondrial production of reactive oxygen species is increased by glucose deficiency. The knockdown of CLDN2 enhanced the flux of 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-D-glucose (2-NBDG), a fluorescent deoxyglucose derivative, in a transwell assay, and the accumulation of glucose and 2-NBDG in spheroid cells. The expression of Nrf2 was decreased by CLDN2 knockdown, which was inhibited by fasentin and sulforaphane, a typical Nrf2 activator, in spheroid cells. The sensitivity of spheroid cells to doxorubicin, an anthracycline antitumor antibiotic, was enhanced by CLDN2 knockdown, which was inhibited by fasentin and sulforaphane. We suggest that CLDN2 induces chemoresistance in spheroid cells mediated through the inhibition of glucose transport and activation of the Nrf2 signal.

Chronic exposure to cathinone derivatives increases the risk of severe health hazards, whereas little is known about the detailed pathogenic mechanisms triggered by the derivatives. We have recently shown that treatment with α-pyrrolidinononanophenone (α-PNP, a highly lipophilic cathinone derivative possessing a long hydrocarbon main chain) provokes neuronal cell apoptosis and its 4′-fluorinated analog (F-α-PNP) potently augments the apoptotic effect. In this study, we found that neuronal SK-N-SH cell damage elicited by F-α-PNP treatment is augmented most potently by pre-incubation with an AKR1B1 inhibitor tolrestat, among specific inhibitors of four aldo–keto reductase (AKR) family members (1B1, 1C1, 1C2, and 1C3) expressed in the neuronal cells. In addition, forced overexpression of AKR1B1 remarkably lowered the cell sensitivity to F-α-PNP toxicity, clearly indicating that AKR1B1 protects from neurotoxicity of the derivative. Treatment of SK-N-SH cells with F-α-PNP resulted in a dose-dependent up-regulation of AKR1B1 expression and activation of its transcription factor NF-E2-related factor 2. Metabolic analyses using liquid chromatography/mass spectrometry/mass spectrometry revealed that AKR1B1 is hardly involved in the F-α-PNP metabolism. The F-α-PNP treatment resulted in production of reactive oxygen species and lipid peroxidation byproduct 4-hydroxy-2-nonenal (HNE) in the cells. The enhanced HNE level was reduced by overexpression of AKR1B1, which also lessened the cell damage elicited by HNE. These results suggest that the AKR1B1-mediated neuronal cell protection is due to detoxification of HNE formed by F-α-PNP treatment, but not to metabolism of the derivative.

We demonstrate the feasibility of using a combination of alkali atoms (Na and K) to develop a robust mixed-alkali honeycomb layered oxide NaKNi2TeO6. Through a series of atomic-resolution transmission electron microscopy in multiple zone axes, we reveal for the first time the local atomic structural disorders characterised by aperiodic stackings and incoherency in the alternating arrangement of Na and K atoms. Our findings indicate great structural versatility that renders NaKNi2TeO6 an ideal platform for investigating other fascinating properties such as mixed ionic transport and intriguing electromagnetic and quantum phenomena amongst honeycomb layered oxides. Finally, we unveil the possibility of inducing mixed Na- and K-ion transport electrochemistry of NaKNi2TeO6 at high voltages (~ 4V), thus epitomising it as a competent cathode candidate for the emerging dendrite-free batteries based on NaK liquid metal alloy as anodes. The results not only betoken a new avenue for developing functional materials with fascinating crystal versatility, but also prefigure a new age of ‘dendrite-free’ energy storage system designs that rely on mixed-cation electrochemistry.

Claudin-2 (CLDN2), an integral membrane protein located at tight junctions, is abnormally expressed in human lung adenocarcinoma tissues, and is linked to drug resistance in human lung adenocarcinoma A549 cells. CLDN2 may be a target for the prevention of lung adenocarcinoma, but there are few compounds which can reduce CLDN2 expression. We found that cyanidin-3-glucoside (C3G), the anthocyanin with two hydroxyl groups on the B-ring, and cyanidin significantly reduce the protein level of CLDN2 in A549 cells. In contrast, pelargonidin-3-glucoside (P3G), the anthocyanin with one hydroxyl group on the B-ring, had no effect. These results suggest that cyanidin and the hydroxyl group at the 3-position on the B-ring play an important role in the reduction of CLDN2 expression. The phosphorylation of Akt, an activator of CLDN2 expression at the transcriptional level, was inhibited by C3G, but not by P3G. The endocytosis and lysosomal degradation are suggested to be involved in the C3G-induced decrease in CLDN2 protein expression. C3G increased the phosphorylation of p38 and the p38 inhibitor SB203580 rescued the C3G-induced decrease in CLDN2 expression. In addition, SB203580 rescued the protein stability of CLDN2. C3G may reduce CLDN2 expression at the transcriptional and post-translational steps mediated by inhibiting Akt and activating p38, respectively. C3G enhanced the accumulation and cytotoxicity of doxorubicin (DXR) in the spheroid models. The percentages of apoptotic and necrotic cells induced by DXR were increased by C3G. Our data suggest that C3G-rich foods can prevent the chemoresistance of lung adenocarcinoma A549 cells through the reduction of CLDN2 expression.

While atomic disorder has provided a paradigm shift in crystalline materials because of unusual atomic arrangements and functional response, “partial” disorder is scarcely reported until now. We discovered partial cation disorder in Li2MnO3 with fewer stacking faults, which was synthesized under high pressure. Mn and Li atoms in a Mn2/3Li1/3O2 layer disorder while Li atoms in a Li layer order. Magnetization and specific heat measurements indicate a long-range antiferromagnetic (AF) order below 35 K. The irreversibility observed in the magnetization data and the hump observed for the specific heat data suggest the coexistence of an AF order and a partial magnetic disorder. Neutron diffraction measurements reveal that the coexisted state is formed instead of the Néel AF state that has previously been reported for conventional Li2MnO3. These results indicate that high pressure makes a breakthrough to introduce partial disorder within crystals and designs not only a unique magnetic structure but also other physical properties.