Influence of a bearing-wastewater phenolic compound (3,4-dimethylphenol, 3,4-DMP) treatment on Ca2+ homeostasis and its related cytotoxicity in human proximal renal tubular epithelial cells.

A lot of phenolic compounds are widespread in industrial effluents and they are considerable environmental pollutants. Being a compound commercially available, the effect of a bearing-wastewater phenolic compound 3,4-dimethylphenol (3,4-DMP) on Ca2+ homeostasis and its related physiology has not been explored in cultured human kidney cell models. The aim of this study was to explore the effect of 3,4-DMP on [Ca2+]i and viability in HK-2 human proximal renal tubular epithelial cells. In terms of Ca2+ signaling, 3,4-DMP (5-100 µM) induced [Ca2+]i rises only in HK-2 cells and Ca2+ removal reduced the signal by 40%. In Ca2+-containing medium, 3,4-DMP-induced Ca2+ entry was inhibited by 20% by a modulator of store-operated Ca2+ channels (2-APB), and by a PKC activator (PMA) and inhibitor (GF109203X). Moreover, 3,4-DMP-induced Mn2+ influx suggesting of Ca2+ entry. In Ca2+-free medium, inhibition of PLC with U73122 abolished 3,4-DMP-induced [Ca2+]i rises. Furthermore, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin abolished 3,4-DMP-evoked [Ca2+]i rises. Conversely, treatment with 3,4-DMP abolished thapsigargin-evoked [Ca2+]i rises. Regarding to cell viability, 3,4-DMP (60-140 µM) killed cells in a concentration-dependent fashion in HK-2 cells. Chelation of cytosolic Ca2+ with BAPTA-AM partially reversed cytotoxicity of 3,4-DMP. Collectively, our data suggest that in HK-2 cells, 3,4-DMP-induced [Ca2+]i rises by evoking Ca2+ entry via PKC-sensitive store-operated Ca2+ entry and PLC-dependent Ca2+ release from the endoplasmic reticulum. 3,4-DMP also caused cytotoxicity that was linked to preceding [Ca2+]i rises. Our findings provide new insight into the cytotoxic effects of 3,4-DMP and the possible mechanisms underlying these effects.

Action of the insecticide cyfluthrin on Ca2+ signal transduction and cytotoxicity in human osteosarcoma cells.

Cyfluthrin is a pyrethroid insecticide and common household pesticide. The effect of cyfluthrin on Ca2+-related physiology in human osteosarcoma is unclear. This study investigated the effect of cyfluthrin on cytosolic-free Ca2+ concentrations ([Ca2+]i) and viability in MG63 human osteosarcoma cells. Cyfluthrin concentration-dependently induced [Ca2+]i rises. Cyfluthrin-induced Ca2+ entry was confirmed by the Mn2+-induced quench of fura-2 fluorescence. Cyfluthrin at concentrations of 10-100 µM induced [Ca2+]i rises. Ca2+ removal reduced the signal by approximately 50%. Cyfluthrin (100 µM) induced Mn2+ influx suggesting Ca2+ entry. Cyfluthrin-induced Ca2+ entry was inhibited 50% by protein kinase C (PKC) activator (phorbol 12-myristate 13-acetate) and inhibitor (GF109203X) and also by three inhibitors of store-operated Ca2+ channels: nifedipine, econazole, and SKF96365. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (TG) completely inhibited cyfluthrin-evoked [Ca2+]i rises. Conversely, treatment with cyfluthrin abolished TG-evoked [Ca2+]i rises. Inhibition of phospholipase C (PLC) with 1-[6-[((17ß)-3-methoxyestra-1,3,5[10]-trien-17-yl)amino]hexyl]-1H-pyrrole-2,5-dion abolished cyfluthrin-induced [Ca2+]i rises. Cyfluthrin at 25-65 µM decreased cell viability, which was not reversed by pretreatment with the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester. Together, in MG63 cells, cyfluthrin induced [Ca2+]i rises by evoking PLC-dependent Ca2+ release from the endoplasmic reticulum and Ca2+ entry via PKC-sensitive store-operated Ca2+ entry. Cyfluthrin also caused Ca2+-independent cell death.

Ca2+ movement and cytotoxicity induced by the pyrethroid pesticide bifenthrin in human prostate cancer cells.

Bifenthrin, a commonly used pyrethroid pesticide, evokes various toxicological effects in different models. However, the effect of bifenthrin on cytosolic-free Ca2+ level ([Ca2+]i) and cytotoxicity in human prostate cancer cells is unclear. This study examined whether bifenthrin altered Ca2+ homeostasis and cell viability in PC3 human prostate cancer cells. [Ca2+]i in suspended cells were measured using the fluorescent Ca2+-sensitive dye fura-2. Cell viability was examined by 4-[3-[4-lodophenyl]-2-4(4-nitrophenyl)-2H-5-tetrazolio-1,3-benzene disulfonate] water soluble tetrazolium-1 assay. Bifenthrin (100-400 µM) concentration-dependently induced [Ca2+]i rises. Ca2+ removal reduced the signal by approximately 30%. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) abolished bifenthrin-evoked [Ca2+]i rises. Conversely, treatment with bifenthrin abolished BHQ-evoked [Ca2+]i rises. Inhibition of phospholipase C (PLC) with U73122 significantly inhibited bifenthrin-induced [Ca2+]i rises. Mn2+ has been shown to enter cells through similar mechanisms as Ca2+ but quenches fura-2 fluorescence at all excitation wavelengths. Bifenthrin (400 µM)-induced Mn2+ influx implicates that Ca2+ entry occurred. Bifenthrin-induced Ca2+ entry was inhibited by 30% by protein kinase C (PKC) activator (phorbol 12-myristate 13 acetate) and inhibitor (GF109203X) and three inhibitors of store-operated Ca2+ channels: nifedipine, econazole, and SKF96365. Bifenthrin at 175-275 µM decreased cell viability, which was not reversed by pretreatment with the Ca2+ chelator 1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetra acetic acid-acetoxymethyl ester. Together, in PC3 cells, bifenthrin-induced [Ca2+]i rises by evoking PLC-dependent Ca2+ release from the endoplasmic reticulum and Ca2+ entry via PKC-sensitive store-operated Ca2+ entry. Bifenthrin also caused Ca2+-independent cell death.

In-situ tensile testing of ZrCu-based metallic glass composites.

ZrCu-based bulk metallic glass composites (BMGCs) are well known for their plastic deformability, superior to traditional metallic glasses (MGs), which is attributed to a unique dual-phases structure, namely, the glassy matrix and unstable B2 phase. In the present study, in-situ tensile testing is used to trace the deformation process of a ZrCu-based BMGC. Three deformation stages of the BMGC, i.e., the elastic-elastic stage, the elastic-plastic stage, and the plastic-plastic stage are identified. In the elastic-elastic and elastic-plastic stages, the yield strength and elastic limit are major influenced by the volume fraction of the B2 crystals. In the plastic-plastic stage, the B2 phase stimulates the formation of multiple shear bands and deflects the direction of shear bands by disturbing the stress field in front of the crack tip. The deformation-induced martensitic transformation of the metastable B2 phase contributes to the plasticity and work hardening of the composite. This study highlights the formation and propagation of multiple shear bands and reveals the interactions of shear bands with structural heterogeneities in situ. Especially, the blocking of shear bands by crystals and the martensitic transformation of the B2 phase are critical for the mechanistic deformation process and illustrate the function of the B2 phase in the present BMGCs.

Amitriptyline modulated Ca2+ signaling and induced Ca2+-independent cell viability in human osteosarcoma cells.

Amitriptyline is a widely used tricyclic antidepressant, which acts primarily as a serotonin-norepinephrine reuptake inhibitor. This study examined the effect of amitriptyline on Ca2+ homeostasis and its related mechanism in MG63 human osteosarcoma cells. Amitriptyline evoked cytosolic-free Ca2+ concentrations ([Ca2+]i) rises concentration dependently. Amitriptyline-evoked Ca2+ entry was confirmed by Mn2+-induced quench of fura-2 fluorescence. This entry was inhibited by Ca2+ entry modulators nifedipine, econazole, SKF96365, the protein kinase C (PKC) activator phorbol 12-myristate 13 acetate but was not affected by the PKC inhibitor GF109203X. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (TG) inhibited amitriptyline-evoked [Ca2+]i rises by 95%. Conversely, treatment with amitriptyline abolished TG-evoked [Ca2+]i rises. Inhibition of phospholipase C (PLC) with U73122 inhibited amitriptyline-evoked [Ca2+]i rises by 70%. Amitriptyline killed cells at 200-500 µM in a concentration-dependent fashion. Chelating cytosolic Ca2+ with 1,2-bis(2-aminophenoxy)ethane- N, N, N', N'-tetraacetic acid/AM did not reverse amitriptyline-induced cytotoxicity. Collectively, our data suggest that in MG63 cells, amitriptyline induced [Ca2+]i rises by evoking PLC-dependent Ca2+ release from the endoplasmic reticulum and Ca2+ entry via PKC-regulated store-operated Ca2+ entry. Amitriptyline also induced Ca2+-disassociated cell death.

Effects of c-Jun N-terminal kinase on Activin A/Smads signaling in PC12 cell suffered from oxygen-glucose deprivation.

Activin A (Act A), a member of transforming growth factor-ß (TGF-ß) superfamily, is an early gene in response to cerebral ischemia. Growing evidences confirm the neuroprotective effect of Act A in ischemic injury through Act A/Smads signal activation. In this process, regulation networks are involved in modulating the outcomes of Smads signaling. Among these regulators, crosstalk between c-Jun N-terminal kinase (JNK) and Smads signaling has been found in the TGF-ß induced epithelial-mesenchymal transition. However, in neural ischemia, the speculative regulation between JNK and Act A/Smads signaling pathways has not been clarified. To explore this issue, an Oxygen Glucose Deprivation (OGD) model was introduced to nerve-like PC12 cells. We found that JNK signal activation occurred at the early time of OGD injury (1 h). Act A administration suppressed JNK phosphorylation. In addition, JNK inhibition could elevate the strength of Smads signaling and attenuate neural apoptosis after OGD injury. Our results indicated a negative regulation effect of JNK on Smads signaling in ischemic injury. Taken together, JNK, as a critical site for neural apoptosis and negative regulator for Act A/Smads signaling, was presumed to be a molecular therapeutic target for ischemia.

Naproxen-induced Ca2+ movement and death in MDCK canine renal tubular cells.

Naproxen is an anti-inflammatory drug that affects cellular calcium ion (Ca(2+)) homeostasis and viability in different cells. This study explored the effect of naproxen on [Ca(2+)](i) and viability in Madin-Darby canine kidney cells (MDCK) canine renal tubular cells. At concentrations between 50 µM and 300 µM, naproxen induced [Ca(2+)](i) rises in a concentration-dependent manner. This Ca(2+) signal was reduced partly when extracellular Ca(2+) was removed. The Ca(2+) signal was inhibited by a Ca(2+) channel blocker nifedipine but not by store-operated Ca(2+) channel inhibitors (econazole and SKF96365), a protein kinase C (PKC) activator phorbol 12-myristate 13-acetate, and a PKC inhibitor GF109203X. In Ca(2+)-free medium, pretreatment with 2,5-di-tert-butylhydroquinone or thapsigargin, an inhibitor of endoplasmic reticulum Ca(2+) pumps, partly inhibited naproxen-induced Ca(2+) signal. Inhibition of phospholipase C with U73122 did not alter naproxen-evoked [Ca(2+)](i) rises. At concentrations between 15 µM and 30 µM, naproxen killed cells in a concentration-dependent manner, which was not reversed by prechelating cytosolic Ca(2+) with the acetoxymethyl ester of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl. Annexin V/propidium iodide staining data suggest that naproxen induced apoptosis. Together, in MDCK renal tubular cells, naproxen induced [Ca(2+)](i) rises by inducing Ca(2+) release from multiple stores that included the endoplasmic reticulum and Ca(2+) entry via nifedipine-sensitive Ca(2+) channels. Naproxen induced cell death that involved apoptosis.

Mechanisms of resveratrol-induced changes in cytosolic free calcium ion concentrations and cell viability in OC2 human oral cancer cells.

Resveratrol is a natural compound that affects cellular calcium (Ca(2+)) homeostasis and viability in different cells. This study examined the effect of resveratrol on cytosolic free Ca(2+) concentrations ([Ca(2+)]i) and viability in OC2 human oral cancer cells. The Ca(2+)-sensitive fluorescent dye fura-2 was used to measure [Ca(2+)]i, and water-soluble tetrazolium-1 was used to measure viability. Resveratrol evoked concentration-dependent increase in [Ca(2+)]i. The response was reduced by removing extracellular Ca(2+). Resveratrol also caused manganese-induced fura-2 fluorescence quench. Resveratrol-evoked Ca(2+) entry was inhibited by nifedipine and the protein kinase C (PKC) inhibitor GF109203X but was not altered by econazole, SKF96365, and the PKC activator phorbol 12-myristate 13 acetate. In Ca(2+)-free medium, treatment with the endoplasmic reticulum Ca(2+) pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) abolished resveratrol-evoked [Ca(2+)]i rise. Conversely, treatment with resveratrol inhibited BHQ-evoked [Ca(2+)]i rise. Inhibition of phospholipase C (PLC) with U73122 abolished resveratrol-evoked [Ca(2+)]i rise. At 20-100 µM, resveratrol decreased cell viability, which was not affected by chelating cytosolic Ca(2+)with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester. Annexin V-fluorescein isothiocyanate staining data suggest that resveratrol at 20-40 µM induced apoptosis in a concentration-dependent manner. Collectively, in OC2 cells, resveratrol induced [Ca(2+)]i rise by evoking PLC-dependent Ca(2+) release from the endoplasmic reticulum and by causing Ca(2+) entry via nifedipine-sensitive, PKC-regulated mechanisms. Resveratrol also caused Ca(2+)-independent apoptosis.

Celecoxib-induced increase in cytosolic Ca(2+) levels and apoptosis in HA59T human hepatoma cells.

Celecoxib has been shown to have antitumor effect in previous studies but the mechanisms are unclear. The effect of celecoxib on cytosolic Ca(2+) concentrations ([Ca(2+)]i) and viability in HA59T human hepatoma cells was explored. The Ca(2+)-sensitive fluorescent dye fura-2 was applied to measure [Ca(2+)]i. Celecoxib at concentrations of 10-50 µM induced a [Ca(2+)]i rise in a concentration-dependent manner. The response was reduced by 80% by removing Ca(2+). Celecoxib induced Mn(2+) influx, leading to quenching of fura-2 fluorescence. Celecoxib-evoked Ca(2+) entry was suppressed by nifedipine, econazole, SK&F96365, and protein kinase C modulators. In the absence of extracellular Ca(2+), incubation with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin nearly abolished celecoxib-induced [Ca(2+)]i rise. Incubation with celecoxib abolished thapsigargin-induced [Ca(2+)]i rise. Inhibition of phospholipase C with U73122 abolished celecoxib-induced [Ca(2+)]i rise. At 1-50 µM, celecoxib inhibited cell viability by less than 20%, which was not reversed by chelating cytosolic Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N, N, N', N'-tetraacetic acid/acetoxy methyl (BAPTA/AM). Celecoxib (10-50 µM) also induced apoptosis. In sum, in HA59T hepatoma cells, celecoxib induced a [Ca(2+)]i rise by evoking phospholipase C-dependent Ca(2+) release from the endoplasmic reticulum and Ca(2+) entry via protein kinase C-sensitive store-operated Ca(2+) channels. Celecoxib also caused cell death via apoptosis.

Advanced glycation end products as an upstream molecule triggers ROS-induced sFlt-1 production in extravillous trophoblasts: a novel bridge between oxidative stress and preeclampsia.

Although abnormal soluble fms-like tyrosine kinase-1 (sFlt-1) production is thought to be an important factor in the pathogenesis of pre-eclampsia, the mechanisms that regulate the production of sFlt-1 during pre-eclampsia are unclear. Accumulation of advanced glycation end products (AGEs) is prevalent in obesity, advanced maternal age, diabetes mellitus, and polycystic ovary syndrome. Alterations in the regulation and signaling of angiogenic pathways have been considered as a link between these conditions and pre-eclampsia. The purpose of this study was to explore the possible effects of AGEs on sFlt-1 secretion in extravillous trophoblasts (EVT). A EVT cell line (HRT-8/SVneo) was treated with various concentrations of AGEs-BSA. The mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in EVT were detected with real-time polymerase chain reaction. The secretion of sFlt-1, VEGF, and PlGF protein from EVT was measured with ELISA. The levels of intracellular reactive oxygen species (ROS) production were determined by DCFH-DA. Exposure of EVT to AGEs-BSA induced increased intracellular ROS generation and overexpression of sFlt-1 at mRNA and protein levels in a dose dependent manner. Anti-RAGE immunoglobulin G or apocynin (an inhibitors of NADPH oxidase) could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels. Our data suggested that AGEs may be a new class of important mediator in the regulation of angiogenic pathways of EVT. Accumulation of AGEs might contribute to the pathogenesis of preeclampsia by promoting sFlt-1 production through activation of RAGE/NADPH oxidase dependent pathway in EVT.

Linear scaling calculation of maximally localized Wannier functions with atomic basis set.

We have developed a linear scaling algorithm for calculating maximally localized Wannier functions (MLWFs) using atomic orbital basis. An O(N) ground state calculation is carried out to get the density matrix (DM). Through a projection of the DM onto atomic orbitals and a subsequent O(N) orthogonalization, we obtain initial orthogonal localized orbitals. These orbitals can be maximally localized in linear scaling by simple Jacobi sweeps. Our O(N) method is validated by applying it to water molecule and wurtzite ZnO. The linear scaling behavior of the new method is demonstrated by computing the MLWFs of boron nitride nanotubes.

Spin-unrestricted linear-scaling electronic structure theory and its application to magnetic carbon-doped boron nitride nanotubes.

We present an extension of the density-matrix-based linear-scaling electronic structure theory to incorporate spin degrees of freedom. When the spin multiplicity of the system can be predetermined, the generalization of the existing linear-scaling methods to spin-unrestricted cases is straightforward. However, without calculations it is hard to determine the spin multiplicity of some complex systems, such as many magnetic nanostuctures and some inorganic or bioinorganic molecules. Here we give a general prescription to obtain the spin-unrestricted ground state of open-shell systems. Our methods are implemented into the linear-scaling trace-correcting density-matrix purification algorithm. The numerical atomic-orbital basis, rather than the commonly adopted Gaussian basis functions, is used. The test systems include O2 molecule and magnetic carbon-doped boron nitride (BN)(5,5) and BN(7,6) nanotubes. Using the newly developed method, we find that the magnetic moments in carbon-doped BN nanotubes couple antiferromagnetically with each other. Our results suggest that the linear-scaling spin-unrestricted trace-correcting purification method is very powerful to treat large magnetic systems.

[Chemical constituents of Corydalis decumbens (Thunb.) Pers].

Six compounds were isolated from the quaternary ammoruinn parts of the bulbs of Corydalis decumbenbs in Shangrao District. The structures of menisperine and ferulic acid obtained for the first time from this plant were identified. Other compounds were found identical with the literature so far reported.