Search

Abstract Asthma is a chronic airway inflammatory disease in which CD4+ T cell dysregulation occurs. Here, we investigated the molecular role and clinical significance of CD226, a costimulatory molecule of T lymphocytes, in the development of allergic asthma. Our results revealed that the expression of CD226 was significantly increased in CD4+ effector T cells, especially in T helper (Th) 2 cells and Th17 cells in patients with asthma. Moreover, CD4+ T cell-specific Cd226-knockout mice were generated and together with littermates were challenged with ovalbumin (OVA) to establish a model of allergic asthma. We found that CD226 deficiency in CD4+ T cells mitigated lung inflammation, IgE production, and eosinophil infiltration and reduced airway remodeling in experimental allergic asthma. However, the impact of CD226 on asthma was independent of Treg cell modulation. Through RNA-seq data analysis, the apoptosis pathway was screened. Mechanistically, CD226 deletion promoted CD4+ T cell late apoptosis via the activation of Caspase-3 in an Akt-dependent manner. Furthermore, blocking CD226 signaling with a recombinant fusion protein attenuated asthma features in mice and achieved a good therapeutic effect. Overall, this study revealed a unique role of CD226 in CD4+ T cell regulation in asthma pathogenesis. Therefore, targeting CD226 may provide new insights into the clinical treatment of asthma.

Underwater noise from anthropogenic activities can have negative behavioral and physical effects on marine life, including physical changes, injuries, and death. Impact pile driving and vibratory pile driving are generally used for the construction of ocean-based foundations. Based on the field data under the same marine engineering and marine environment, this paper addresses the characteristics of underwater noise from impact and vibratory pile driving, their differences, and the effects of noise on populations of the large yellow croaker (Pseudosciaena crocea). The impact pile driving pulse had a median peak-to-peak sound pressure source level (SPLpp) of 244.7 dB re 1 μPa at 1 m and a median sound exposure source level (SELss) of 208.1 dB re 1 μPa2s at 1 m by linear regression. The waveform of vibratory pile driving appears to be continuous with a low SPLpp, but the cumulative SEL (SELcum) in 1 min is very high, reaching 207.5 dB re 1 μPa2s at 1 m. The range of behavioral response for adult large yellow croaker (20–23 cm) is predicted to be 4,798 m for impact pile driving and 1,779 m for vibratory pile driving. The study provides evidence of the comparative potential effects of vibratory and impact pile driving on the large yellow croaker and reference for the conservation of croaker.

The essential role of store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ (CRAC) channels in T cells is well established. In contrast, the contribution of individual Orai isoforms to SOCE and their downstream signaling functions in B cells are poorly understood. Here, we demonstrate changes in the expression of Orai isoforms in response to B cell activation. We show that both Orai3 and Orai1 mediate native CRAC channels in B cells. The combined loss of Orai1 and Orai3, but not Orai3 alone, impairs SOCE, proliferation and survival, nuclear factor of activated T cells (NFAT) activation, mitochondrial respiration, glycolysis, and the metabolic reprogramming of primary B cells in response to antigenic stimulation. Nevertheless, the combined deletion of Orai1 and Orai3 in B cells did not compromise humoral immunity to influenza A virus infection in mice, suggesting that other in vivo co-stimulatory signals can overcome the requirement of BCR-mediated CRAC channel function in B cells. Our results shed important new light on the physiological roles of Orai1 and Orai3 proteins in SOCE and the effector functions of B lymphocytes.

The essential role of ORAI1 channels in receptor-evoked Ca2+ signaling is well understood, but the roles of ORAI2 and ORAI3 remained obscure. Here authors show that ORAI2 and ORAI3 channels multimerize with ORAI1 to expand the range of sensitivity of receptor-activated Ca2+ signals, reflecting their enhanced basal STIM1-binding and heightened Ca2+-dependent inactivation.

This article is devoted to study the axial compression behaviour of recycled concrete-filled steel tubular (RCFST) columns after high temperature. Several axial compression members’ internal mechanisms are analyzed by combining experimental and finite element analysis (FEA). Firstly, the failure mode of axial compression members is studied by experiments. Then, based on the correct constitutive relationship between recycled concrete and steel, the finite element model is established by ABAQUS software, and theoretical analysis and experimental verification are carried out, which are in good agreement. The effects of different parameters such as temperature, substitution rate, and bond strength of the coefficient on the whole load-strain curve are compared. The results show that the bearing capacity of recycled concrete-filled steel tubular columns decreases with the increase in temperature and replacement rate. The bond coefficient between steel tubular and core concrete has little effect on the specimen’s overall axial compressive mechanical properties. The interaction force P rises slightly along the height after the high temperature at the peak load, as it gradually moves away from the cover. In the square section, corners show stress concentration, and bulge deformation occurs first under the condition of axial compression.

Abstract Rejection is a common complication of allogeneic tissue transplantation. Fixation of splenocytes (SP) with 1‐ethyl‐3‐(3'‐dimethylaminopropyl)‐carbodiimide (ECDI) induces immune tolerance in recipients post‐transplantation; however, the mechanism underlying this effect remains unclear. Here, we determined the mechanisms of ECDI‐fixed donor SP (ECDI‐SP) in inducing tolerance in skin allograft transplantation. C57BL/6‐recipient mice that received Balb/c full‐thickness skin transplants with two infusions of donor‐derived ECDI‐SP, along with rapamycin showed superior skin allograft survival and lower inflammatory cell infiltration than mice that received rapamycin‐only treatment. In ECDI‐SP‐treated mice, the levels of anti‐inflammatory cytokines such as interleukin (IL)‐10 in sera were markedly increased, whereas the expression of inflammatory cytokines was significantly suppressed. Splenic macrophages were significantly polarized to the alternative activated macrophage (M2) phenotype, with expansion of CD4+Foxp3+ regulatory T cells (Tregs) in the spleen and draining lymph nodes. Allostimulatory activity of ECDI‐SP in vitro and donor‐specific ex vivo hyporesponsiveness were observed. C57BL/6 macrophages engulfed allogeneic Balb/c‐derived ECDI‐SP, polarized to the M2 phenotype, with pronounced cAMP response element‐binding (CREB) protein phosphorylation. By facilitating increased IL‐10 expression, ECDI‐SP induced M2 polarization and Treg production, inhibiting effector T‐cell proliferation. Thus, ECDI‐SP modulates macrophage M2 polarization by increasing CREB phosphorylation and promoting Treg production to suppress allogeneic skin graft rejection.

ORAI1 constitutes the store-operated Ca2+ release-activated Ca2+ (CRAC) channel, but how this channel is turned off through Ca2+-dependent inactivation (CDI) remained unclear. Here the authors identify a spatially-restricted Ca2+/cAMP signaling crosstalk critical for mediating CDI which in turn regulates cellular Ca2+ signals and NFAT activation.

Despite the established role of mitochondria in cancer, the mechanisms by which mitochondrial Ca2+ (mtCa2+) regulates tumorigenesis remain incompletely understood. The crucial role of mtCa2+ in tumorigenesis is highlighted by altered expression of proteins mediating mtCa2+ uptake and extrusion in cancer. Here, we demonstrate decreased expression of the mitochondrial Na+/Ca2+/Li+ exchanger NCLX (SLC8B1) in human colorectal tumors and its association with advanced-stage disease in patients. Downregulation of NCLX causes mtCa2+ overload, mitochondrial depolarization, decreased expression of cell-cycle genes and reduced tumor size in xenograft and spontaneous colorectal cancer mouse models. Concomitantly, NCLX downregulation drives metastatic spread, chemoresistance, and expression of epithelial-to-mesenchymal, hypoxia, and stem cell pathways. Mechanistically, mtCa2+ overload leads to increased mitochondrial reactive oxygen species, which activate HIF1α signaling supporting metastasis of NCLX-null tumor cells. Thus, loss of NCLX is a novel driver of metastasis, indicating that regulation of mtCa2+ is a novel therapeutic approach in metastatic colorectal cancer.

Polyomino graphs is one of the research objectives in statistical physics and in modeling problems of surface chemistry. A random polyomino chain is a subgraph of a polyomino graph. The matching energy is defined as the sum of the absolute values of the zeros of the matching polynomial of a graph. In this paper, we characterize the graphs with the extremal matching energy among all random polyomino chains of a polyomino graph by the probability method.

Airway remodeling and airway hyperresponsiveness are central drivers of asthma severity. Airway remodeling is a structural change involving the dedifferentiation of airway smooth muscle (ASM) cells from a quiescent to a proliferative and secretory phenotype. Here, we show up-regulation of the endoplasmic reticulum Ca2+ sensor stromal-interacting molecule 1 (STIM1) in ASM of asthmatic mice. STIM1 is required for metabolic and transcriptional reprogramming that supports airway remodeling, including ASM proliferation, migration, secretion of cytokines and extracellular matrix, enhanced mitochondrial mass, and increased oxidative phosphorylation and glycolytic flux. Mechanistically, STIM1- mediated Ca2+ influx is critical for the activation of nuclear factor of activated T cells 4 and subsequent interleukin-6 secretion and transcription of pro-remodeling transcription factors, growth factors, surface receptors, and asthma-associated proteins. STIM1 drives airway hyperresponsiveness in asthmatic mice through enhanced frequency and amplitude of ASM cytosolic Ca2+ oscillations. Our data advocates for ASM STIM1 as a target for asthma therapy. [ABSTRACT FROM AUTHOR]

Protein kinase C (PKC)-ε is required for membrane addition during IgG-mediated phagocytosis, but its role in this process is ill defined. Here, we performed high-resolution imaging, which reveals that PKC- ε exits the Golgi and enters phagosomes on vesicles that then fuse. TNF and PKC-ε colocalize at the Golgi and on vesicles that enter the phagosome. Loss of PKC-ε and TNF delivery upon nocodazole treatment confirmed vesicular transport on microtubules. That TNF+ vesicles were not delivered in macrophages from PKC-ε null mice, or upon dissociation of the Golgi-associated pool of PKC-ε, implies that Golgi-tethered PKC-ε is a driver of Golgi-to-phagosome trafficking. Finally, we established that the regulatory domain of PKC-ε is sufficient for delivery of TNF+ vesicles to the phagosome. These studies reveal a novel role for PKC-ε in focal exocytosis -- its regulatory domain drives Golgi-derived vesicles to the phagosome, whereas catalytic activity is required for their fusion. This is one of the first examples of a PKC requirement for vesicular trafficking and describes a novel function for a PKC regulatory domain. This article has an associated First Person interview with the first author of the paper. [ABSTRACT FROM AUTHOR]

Voltage-gated L-type Ca2+ channel (Cav1.2) blockers (LCCBs) are major drugs for treating hypertension, the preeminent risk factor for heart failure. Vascular smooth muscle cell (VSMC) remodeling is a pathological hallmark of chronic hypertension. VSMC remodeling is characterized by molecular rewiring of the cellular Ca2+ signaling machinery, including down-regulation of Cav1.2 channels and up-regulation of the endoplasmic reticulum (ER) stromalinteracting molecule (STIM) Ca2+ sensor proteins and the plasma membrane ORAI Ca2+ channels. STIM/ORAI proteins mediate storeoperated Ca2+ entry (SOCE) and drive fibro-proliferative gene programs during cardiovascular remodeling. SOCE is activated by agonists that induce depletion of ER Ca2+, causing STIM to activate ORAI. Here, we show that the three major classes of LCCBs activate STIM/ORAI-mediated Ca2+ entry in VSMCs. LCCBs act on the STIM N terminus to cause STIM relocalization to junctions and subsequent ORAI activation in a Cav1.2-independent and store depletionindependent manner. LCCB-induced promotion of VSMC remodeling requires STIM1, which is up-regulated in VSMCs from hypertensive rats. Epidemiology showed that LCCBs are more associated with heart failure than other antihypertensive drugs in patients. Our findings unravel a mechanism of LCCBs action on Ca2+ signaling and demonstrate that LCCBs promote vascular remodeling through STIM-mediated activation of ORAI. Our data indicate caution against the use of LCCBs in elderly patients or patients with advanced hypertension and/or onset of cardiovascular remodeling, where levels of STIM and ORAI are elevated. [ABSTRACT FROM AUTHOR]

Endothelial barrier function is tightly regulated by plasma membrane receptors and is crucial for tissue fluid homeostasis; its dysfunction causes disease, including sepsis and inflammation. The ubiquitous activation of Ca2+ signaling upon phospholipase C-coupled receptor ligation leads quite naturally to the assumption that Ca2+ signaling is required for receptor-regulated endothelial barrier function. This widespread hypothesis draws analogy from smooth muscle and proposes the requirement of G protein-coupled receptor (GPCR)-generated Ca2+ signaling in activating the endothelial contractile apparatus and generating interendothelial gaps. Notwithstanding endothelia being non-excitable in nature, the hypothesis of Ca2+-induced endothelial contraction has been invoked to explain actions of GPCR agonists that either disrupt or stabilize endothelial barrier function. Here, we challenge this correlative hypothesis by showing a lack of causal link between GPCR-generated Ca2+ signaling and changes in human microvascular endothelial barrier function. We used three endogenous GPCR agonists: thrombin and histamine, which disrupt endothelial barrier function, and sphingosine-1-phosphate, which stabilizes barrier function. The qualitatively different effects of these three agonists on endothelial barrier function occur independently of Ca2+ entry through the ubiquitous store-operated Ca2+ entry channel Orai1, global Ca2+ entry across the plasma membrane, and Ca2+ release from internal stores. However, disruption of endothelial barrier function by thrombin and histamine requires the Ca2+ sensor stromal interacting molecule-1 (STIM1), whereas sphingosine-1-phosphate-mediated enhancement of endothelial barrier function occurs independently of STIM1. We conclude that although STIM1 is required for GPCR-mediated disruption of barrier function, a causal link between GPCR-induced cytoplasmic Ca2+ increases and acute changes in barrier function is missing. Thus, the cytosolic Ca2+- induced endothelial contraction is a cum hoc fallacy that should be abandoned. [ABSTRACT FROM AUTHOR]

The roles of secreted frizzled-related protein-1 (SFRP1) and β-catenin in human cancer have been widely studied, and it has recently been demonstrated that these proteins are associated with numerous human carcinomas. However, their clinical significance in glioblastoma multi-forme (GBM) has not been examined. The current study aimed to analyze the correlation between the expression of SFRP1 and β-catenin, and clinicopathological characteristics in GBM patients. The expression of SFRP1 and β-catenin was assessed by immunohistochemistry in 113 samples of GBM and 40 normal brain tissues. Compared with normal brain tissues, GBM tissues exhibited significantly lower expression of SFRP1, and higher expression of β-catenin (both P<0.05). A Kaplan-Meier analysis revealed that patients with positive SFRP1 expression had a significantly longer overall survival (OS) time relative to those with negative SFRP1 expression (P<0.000), and that patients with positive β-catenin expression had a shorter OS time than those with negative β-catenin expression (P<0.000). A multivariate Cox regression analysis indicated that adjuvant treatment, SFRP1 expression and β-catenin expression were independent prognostic factors for OS (P<0.000, P=0.008 and P=0.001, respectively) in patients with GBM. The current data suggest that expression of SFRP1 and β-catenin may be considered significant prognostic indicators for patients with GBM. [ABSTRACT FROM AUTHOR]

Translationally controlled tumor protein (TCTP) is a highly conserved, growth-associated and small molecule protein, which is highly expressed in various types of tumor cell. TCTP can promote the growth and suppress apoptosis of tumor cels. However, few studies have reported the effects of TCTP in gliomas. In the present study, a glioma cell line was established, which was stably transfected with TCTP short hairpin ribonucleic acid (shRNA), to investigate the impact of downregulated expression of TCTP on the proliferation, apoptosis and invasion of glioma cells. Western blot and reverse transcription-quantitative polymerase chain reaction analyses demonstrated that TCTP shRNA effectively reduced the expression of TCTP in the U251 glioma cell line. MTT and colony formation assays revealed that downregulated expression of TCTP significantly inhibited glioma cell proliferation. Cell cycle analysis using flow cytometry revealed that the cells in the pRNA-H1.1-TCTP group were arrested in the G0/G1 phase of the cell cycle. Western blot analysis detected downregulated expression levels of cyclins, including Cyclin D1, Cyclin E and Cyclin B. Annexin V-fluorescein isothiocyanate/ propidium iodide and Hoechst staining demonstrated that the apoptotic rate of the cells in the pRNA-H1.1-TCTP group was significantly higher than that of the cells in the pRNA-H1.1-control group, with upregulated expression levels of B-cell-associated X protein and cleaved-caspase-3 and downregulated expression of B-cell lmyphoma-2 in the apoptotic process. Wound healing and Transwell assays revealed that downregulated expression of TCTP significantly inhibited the migration and invasiveness of the glioma cells; and the expression levels and activities of matrix metalloproteinase (MMP)-2 and MMP-9 were also significantly affected. In conclusion, the present study demonstrated that downregulated expression of TCTP significantly inhibited proliferation and invasion, and induced apoptosis in the glioma cells. These results suggested that TCTP may be important in glioma development and metastasis. Therefore, TCTP is expected to become an effective target for glioma gene therapy. [ABSTRACT FROM AUTHOR]

Increasing evidence has suggested that microRNA-133b (miR-133b) is important in regulating the genesis of different types of cancer. However, the effects and the underlying mechanisms of miR-133b in the development of glioblastoma (GBM) remain largely unknown. The aim of the present study was to investigate the role of miR-133b in GBM and to determine the molecular mechanisms underlying its action. Reverse transcription-quantitative polymerase chain reaction was used to measure the expression levels of miR-133b in 21 human GBM samples and 9 normal brain tissue samples. A wound healing assay, and Transwell migration and invasion assays were used to evaluate the effects of miR-133b on cell migration and invasion. Western blotting and a luciferase reporter assay were used to identify the target genes of miR-133b. It was found that miR-133b suppressed GBM cell migration and invasion, and matrix metalloproteinase 14 (MMP14) was identified as a direct target gene. In conclusion, miR-133b may suppress GBM migration and invasion through directly targeting MMP14, highlighting its potential as a novel agent for the treatment of GBM invasion. [ABSTRACT FROM AUTHOR]

Leukotriene-C4 synthase (LTC4S) generates LTC4 from arachidonic acid metabolism. LTC4 is a proinflammatory factor that acts on plasma membrane cysteinyl leukotriene receptors. Recently, however, we showed that LTC4 was also a cytosolic second messenger that activated store-independent LTC4-regulated Ca2+ (LRC) channels encoded by Orai1/Orai3 heteromultimers in vascular smooth muscle cells (VSMCs). We showed that Orai3 and LRC currents were up-regulated in medial and neointimal VSMCs after vascular injury and that Orai3 knockdown inhibited LRC currents and neointimal hyperplasia. However, the role of LTC4S in neointima formation remains unknown. Here we show that LTC4S knockdown inhibited LRC currents in VSMCs. We performed in vivo experiments where rat left carotid arteries were injured using balloon angioplasty to cause neointimal hyperplasia. Neointima formation was associated with up-regulation of LTC4S protein expression in VSMCs. Inhibition of LTC4S expression in injured carotids by lentiviral particles encoding shRNA inhibited neointima formation and inward and outward vessel remodeling. LRC current activation did not cause nuclear factor for activated T cells (NFAT) nuclear translocation in VSMCs. Surprisingly, knockdown of either LTC4S or Orai3 yielded more robust and sustained Akt1 and Akt2 phosphorylation on Ser-473/Ser-474 upon serum stimulation. LTC4S and Orai3 knockdown inhibited VSMC migration in vitro with no effect on proliferation. Akt activity was suppressed in neointimal and medial VSMCs from injured vessels at 2 weeks postinjury but was restored when the up-regulation of either LTC4S or Orai3 was prevented by shRNA. We conclude that LTC4S and Orai3 altered Akt signaling to promote VSMC migration and neointima formation. [ABSTRACT FROM AUTHOR]

The present study was designed to investigate bilingual memory representations in less fluent Chinese-English bilinguals and the effect of word familiarity on bilingual memory representations with a translation priming paradigm and the event-related potential (ERP) technique. Three factors (translation order, word familiarity, and repetition status) were manipulated in this study, and the major dependent variable was the magnitude of the N400 repetition effect, which is related to semantic expectation and is an important physiological index of language processing. The results confirmed the asymmetry in bilingual memory with stronger L2-LI links compared to L1-L2 links in less fluent Chinese-English bilinguals, and that word familiarity was an important factor in the memory representations of these less fluent bilinguals. [ABSTRACT FROM AUTHOR]

Catalytic synthesis of N-benzothiazol-2-yl-amides from 1-acyl-3-(phenyl)thioureas was achieved in the presence of an iron catalyst through C(sp2)-H functionalization and C-S bond formation. Various N-benzothiazol-2-yl-amides were selectively obtained in good yields. [ABSTRACT FROM AUTHOR]

Orai proteins contribute to Ca2+ entry into cells through both store-dependent, Ca2+ release-activated Ca2+ (CRAC) channels (Orail) and store-independent, arachidonic acid (AA)-regulated Ca2+ (ARC) and leukotriene C4 (LTC4)-regulated Ca2+ (LRC) channels (Orail/3 heteromultimers). Although activated by fundamentally different mecha-nisms, CRAC channels, like ARC and LRC channels, require stromal interacting molecule 1 (STIM1). The role of endoplasmic reticulum-resident STIM1 (ER-STIM1) in CRAC channel activation is widely accepted. Although ER-STIM1 is necessary and sufficient for LRC channel activation in vascular smooth muscle cells (VSMCs), the minor pool of STIM1 located at the plasma membrane (PM-STIM1) is necessary for ARC channel activation in HEK293 cells. To determine whether ARC and LRC conductances are mediated by the same or different populations of STIM1, Orail, and Orai3 proteins, we used whole-cell and perforated patch-clamp recording to compare AA- and LTC.|-activated currents in VSMCs and HEK293 cells. We found that both cell types show indistinguishable nonad-ditive LTC.r and AA-activated currents that require both Orail and Orai3, suggesting that both conductances are mediated by the same channel. Experiments using a nonmetabolizable form of AA or an inhibitor of 5-lipooxygen-ase suggested that ARC and LRC currents in both cell types could be activated by either LTC4 or AA, with LTC4 being more potent. Although PM-STIM1 was required for current activation by LTC4 and AA under whole-cell patch-clamp recordings in both cell types, ER-STIM1 was sufficient with perforated patch recordings. These results demonstrate that ARC and LRC currents are mediated by the same cellular populations of STIM1, Orail, and Orai3, and suggest a complex role for both ER-STIM1 and PM-STIM1 in regulating these store-independent Orail/3 channels. [ABSTRACT FROM AUTHOR]

Compounding is an effective way to express new meanings by combining existing concepts. However, the resultant meaning involves not only the sum of meanings of the two constituent concepts but also the semantic relation between them. Compounding is particularly important for the study of Chinese word recognition as compound word is the dominant type of vocabulary in Chinese. The present commentary describes two recent studies using event-related potentials (ERPs) to examine the time course of lexical processing for Chinese compound words. In the first study, we reported the discovery of a novel ERP component, named the centro-parietal N200, which was elicited about 200ms after the onset of two-character words. Evidence suggests that this N200 reflects recognition of the two characters' orthographic form. In the second study, we used a relation priming paradigm and showed that the relation combining meanings of the two characters was activated in the N400 time window about 80ms later than the meaning activation of the individual characters. Together, the results indicate a clear serial process in reading compound Chinese words, first recognizing the word form around 200ms following word presentation, and then starting to retrieve each character's meaning at around 260ms, and finally integrating the two constituting meanings at around 340ms. [ABSTRACT FROM AUTHOR]

We recently showed, in primary vascular smooth muscle cells (VSMCs), that the platelet-derived growth factor activates canonical store-operated Ca2+ entry and Ca2+ release-activated Ca2+ currents encoded by Orai1 and STIM1 genes. However, thrombin activates store-independent Ca2+ selective channels contributed by both Orai3 and Orai1. These store-independent Orai3/Orai1 channels are gated by cytosolic leukotriene C4 (LTC4) and require STIM1 downstream LTC4 action. However, the source of LTC4 and the signaling mechanisms of STIM1 in the activation of this LTC4-regulated Ca2+ (LRC) channel are unknown. Here, we show that upon thrombin stimulation, LTC4 is produced through the sequential activities of phospholipase C, diacylglycerol lipase, 5-lipo-oxygenease, and leukotriene C4 synthase. We show that the endoplasmic reticulum-resident STIM1 is necessary and sufficient for LRC channel activation by thrombin. STIM1 does not form sustained puncta and does not colocalize with Orai1 either under basal conditions or in response to thrombin. However, STIM1 is precoupled to Orai3 and Orai3/Orai1 channels under basal conditions as shown using Forster resonance energy transfer (FRET) imaging. The second coiled-coil domain of STIM1 is required for coupling to either Orai3 or Orai3/Orai1 channels and for LRC channel activation. We conclude that STIM1 employs distinct mechanisms in the activation of store-dependent and store-independent Ca2+ entry pathways. [ABSTRACT FROM AUTHOR]

Store-operated Ca2+ entry (SOCE) encoded by Orail proteins is a ubiquitous Ca2+-selective conductance involved in cellular proliferation and mi- gration. We recently described up-regulation of Orai3 channels that selectively mediate SOCE in estrogen receptor α-expressing (ERα+) breast cancer cells. How- ever, the connection between ERα and Orai3 and the role of Orai3 in tumorigenesis remain unknown. Here, we show that ERot knockdown decreases Orai3 mRNA (by ~63%) and protein (by ~44%) with no effect on Orail. ERα knockdown decreases Orai3-mediated SOCE (by ~43%) and the corresponding Ca2+ release- activated Ca2+ (CRAC) current (by ~42%) in ERα+ MCF7 cells. The abrogation of SOCE in MCF7 cells on ERα knockdown can be rescued by ectopic expression of Orai3. ERα activation increased Orai3 expression and SOCE in MCF7 cells. Epidermal growth factor (EGF) and thrombin stimulate Ca2+ influx into MCF7 cells through Oral3. Orai3 knockdown inhibited SOCE- dependent phosphorylation of extracellular signal-regulated kinase (ERK1/2; by ~44%) and focal adhesion kinase (FAK; by ~46%) as well as transcriptional activity of nuclear factor for activated T cells (NFAT; by ~49%). Significantly, Orai3 knockdown selectively decreased anchorage-independent growth (by ~58%) and Matrigel invasion (by ~44%) of ERα+ MCF7 cells with no effect on ERα- MDA-MB231 cells. Moreover, Orai3 knockdown inhibited ERα+ cell tumorigenesis in immunodeficient mice (~66% reduction in tumor volume). These data establish Orai3 as an ERα-regulated channel and a potential selective therapeutic target for ERα+ breast cancers. [ABSTRACT FROM AUTHOR]

Two-pore domain K+ channels (K2P) mediate background K+ conductance and play a key role in a variety of cellular functions. Among the 15 mammalian K2P isoforms, TWIK-1, TASK-1, and TASK-3 K+ channels are sensitive to extracellular acidification. Lowered or acidic extracellular pH (pHo) strongly inhibits outward currents through these K2P channels. However, the mechanism of how low pHo affects these acid-sensitive K2P channels is not well understood. Here we show that in Na+- based bath solutions with physiological K+ gradients, lowered pHo largely shifts the reversal potential of TWIK-1, TASK-1, and TASK-3 K+ channels, which are heterologously expressed in Chinese hamster ovary cells, into the depolarizing direction and significantly increases their Na+ to K+ relative permeability. Low pHo-induced inhibitions in these acid-sensitive K2P channels are more profound in Na+-based bath solutions than in channel-impermeable N-methyl-D-glucamine-based bath solutions, consistent with increases in the Na+ to K+ relative permeability and decreases in electrochemical driving forces of outward K+ currents of the channels. These findings indicate that TWIK-1, TASK-1, and TASK-3 K+ channels change ion selectivity in response to lowered pHo, provide insights on the understanding of how extracellular acidification modulates acid-sensitive K2P channels, and imply that these acid-sensitive K2P channels may regulate cellular function with dynamic changes in their ion selectivity. [ABSTRACT FROM AUTHOR]

In Alzheimer disease (AD), the perturbation of the endoplasmic reticulum (ER) calcium (Ca2+) homeostasis has been linked to prese-nilins, the catalytic core in γ-secretase complexes cleaving the amyloid precursor protein (APP), thereby generating amyloid-β (Aβ) peptides. Here we investigate whether APP contributes to ER Ca2+ homeostasis and whether ER Ca2+ could in turn influence Aβ production. We show that overexpression of wild-type human APP ( APP695 ), or APP harboring the Swedish double mutation (APPswe ) triggers increased ryanodine receptor (RyR) expression and enhances RyR-mediated ER Ca2+ release in SH-SY5Y neuroblastoma cells and in APPswe-expressing (Tg2576) mice. Interestingly, dantrolene-induced lowering of RyR-mediated Ca2+ release leads to the reduction of both intracellular and extracellular Aβ load in neuroblastoma cells as well as in primary cultured neurons derived from Tg2576 mice. This Aβ reduction can be accounted for by decreased Thr-668-dependent APP phosphorylation and β- and γ-secretases activities. Importantly, dantrolene diminishes Aβ load, reduces Aβ-related histological lesions, and slows down learning and memory deficits in Tg2576 mice. Overall, our data document a key role of RyR in Aβ production and learning and memory performances, and delineate RyR-mediated control of Ca2+ homeostasis as a physiological paradigm that could be targeted for innovative therapeutic approaches. [ABSTRACT FROM AUTHOR]

The event-related brain potential (ERP) technique was used to investigate the neural mechanism of non-target language processing in Chinese-English bilinguals. Participants were presented with a mixed list of Chinese and English words and required to make conceptual decisions for words in one language and ignore words in the other non-target language. Regardless of whether the non-target word was in Chinese or English, the ERPs they elicited were modulated by word frequency, suggesting that their meaning had been accessed. The N400 peak was delayed in the English as the non-target language condition, probably because participants were less proficient in English. The results suggest that the non-target language can be processed during conceptual tasks with participants' proficiency in this language being a critical factor. [ABSTRACT FROM AUTHOR]

Cystic fibrosis (CF) is caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR). The most common mutation, AF508, causes retention of CFFR in the endoplasmic reticulum (ER). Some CF abnormalities can be explained by altered Ca2+ homeostasis, although it remains unknown how CFTR influences calcium signaling. This study examined the novel hypothesis that store-operated calcium entry (SOCE) through Orail is abnormal in CF. The significance of Orail-mediated SOCE for increased interleukin-8 (IL-8) expression in CF was also investigated. CF and non-CF human airway epithelial cell line and primary cells (obtained at lung transplantation) were used in Ca2+ imaging, electrophysiology, and fluorescence imaging experiments to explore differences in Orail function in CF vs. non-CF cells. Protein expression and localization was assessed by Western blots, cell surface biotinylation, ELISA, and image correlation spectroscopy (ICS). We show here that store-operated Ca2+ entry (SOCE) is elevated in CF human airway epithelial cells (hAECs; ~1.8- and ~2.5-fold for total Ca2+i increase and Ca2+ influx rate, respectively, and ~2-fold increase in the ICRAC current) and is caused by increased exocytotic insertion (~2-fold) of Orail channels into the plasma membrane, which is normalized by rescue of ΔF508-CFTR trafficking to the cell surface. Augmented SOCE in CF cells is a major factor leading to increased IL-8 secretion (~2-fold). CFTR normally down-regulates the Orail/stromal interaction molecule 1 (STIM1) complex, and loss of this inhibition due to the absence of CFTR at the plasma membrane helps to explain the potentiated inflammatory response in CF cells. [ABSTRACT FROM AUTHOR]

One of the central concerns in theories of reading skills is the role of phonology in access to word meaning. The present study focused on this issue in Chinese to examine the extent to which phonology affects Chinese character recognition. Two naming experiments were conducted with a phonologically mediated semantic priming paradigm, and the relative frequencies of semantic associates of the targets and their homophones were manipulated systematically. Analyses showed that a semantic associate produced robust priming on target naming at 57- and 250-msec. stimulus onset asynchronies, but only the low frequency homo- phones of high frequency semantic associates facilitated target naming at a 250- msec. stimulus onset asynchrony. These results indicate the role of phonology is neither obligatory nor efficient in access to Chinese character meaning, contradicting the key assumptions of the lexical constituency model. A revised parallel access model that emphasizes visual access to semantics is suggested as a more plausible account. [ABSTRACT FROM AUTHOR]

One of the central concerns in theories of reading skills is the role of phonology in access to word meaning. The present study focused on this issue in Chinese to examine the extent to which phonology affects Chinese character recognition. Two naming experiments were conducted with a phonologically mediated semantic priming paradigm, and the relative frequencies of semantic associates of the targets and their homophones were manipulated systematically. Analyses showed that a semantic associate produced robust priming on target naming at 57- and 250-msec. stimulus onset asynchronies, but only the low frequency homo- phones of high frequency semantic associates facilitated target naming at a 250- msec. stimulus onset asynchrony. These results indicate the role of phonology is neither obligatory nor efficient in access to Chinese character meaning, contradicting the key assumptions of the lexical constituency model. A revised parallel access model that emphasizes visual access to semantics is suggested as a more plausible account. [ABSTRACT FROM AUTHOR]

Expression of a linear current-voltage (I-V) relationship (passive) K+ membrane conductance is a hallmark of mature hippocampal astrocytes. However, the molecular identifications of the K+channels underlying this passive conductance remain unknown. We provide the following evidence supporting significant contribution of the two-pore domain K+ channel (K2P) isoforms, TWIK-1 and TREK-1, to this conductance. First, both passive astrocytes and the cloned rat TWIK-1 and TREK-1 channels expressed in CHO cells conduct significant amounts of Cs+ currents, but vary in their relative PCs/PK permeability, 0.43, 0.10, and 0.05, respectively. Second, quinine, which potently inhibited TWIK-1 (IC50 = 85 μM) and TREK-1 (IC50 = 41 μM) currents, also inhibited astrocytic passive conductance by 58% at a concentration of 200 μM. Third, a moderate sensitivity of passive conductance to low extracellular pH (6.0) supports a combined expression of acid-insensitive TREK-1, and to a lesser extent, acid-sensitive TWIK-1. Fourth, the astrocyte passive conductance showed low sensitivity to extracellular Ba2+, and extracellular Ba2+ blocked TWIK-1 channels at an IC50 of 960 μM and had no effect on TREK-1 channels. Finally, an immunocytochemical study showed colocalization of TWIK-1 and TREK-1 proteins with the astrocytic markers GLAST and GFAP in rat hippocampal stratum radiatum. In contrast, another K2P isoform TASK-1 was mainly colocalized with the neuronal marker NeuN in hippocampal pyramidal neurons and was expressed at a much lower level in astrocytes. These results support TWIK-1 and TREK-1 as being the major components of the long-sought K+ channels underlying the passive conductance of mature hippocampal astrocytes. [ABSTRACT FROM AUTHOR]