63 research outputs found

    Heteromeric TRPV4/TRPC1 channels mediate calcium-sensing receptor-induced nitric oxide production and vasorelaxation in rabbit mesenteric arteries.

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    Stimulation of calcium-sensing receptors (CaSR) by increasing the external calcium concentration (Ca(2+)]o) induces endothelium-dependent vasorelaxation through nitric oxide (NO) production and activation of intermediate Ca(2+)-activated K(+) currents (IKCa) channels in rabbit mesenteric arteries. The present study investigates the potential role of heteromeric TRPV4-TRPC1 channels in mediating these CaSR-induced vascular responses. Immunocytochemical and proximity ligation assays showed that TRPV4 and TRPC1 proteins were expressed and co-localised at the plasma membrane of freshly isolated endothelial cells (ECs). In wire myography studies, increasing [Ca(2+)]o between 1 and 6mM induced concentration-dependent relaxations of methoxamine (MO)-induced pre-contracted tone, which were inhibited by the TRPV4 antagonists RN1734 and HC067047, and the externally-acting TRPC1 blocking antibody T1E3. In addition, CaSR-evoked NO production in ECs measured using the fluorescent NO indicator DAF-FM was reduced by RN1734 and T1E3. In contrast, [Ca(2+)]o-evoked perforated-patch IKCa currents in ECs were unaffected by RN1734 and T1E3. The TRPV4 agonist GSK1016790A (GSK) induced endothelium-dependent relaxation of MO-evoked pre-contracted tone and increased NO production, which were inhibited by the NO synthase inhibitor L-NAME, RN1734 and T1E3. GSK activated 6pS cation channel activity in cell-attached patches from ECs which was blocked by RN1734 and T1E3. These findings indicate that heteromeric TRPV4-TRPC1 channels mediate CaSR-induced vasorelaxation through NO production but not IKCa channel activation in rabbit mesenteric arteries. This further implicates CaSR-induced pathways and heteromeric TRPV4-TRPC1 channels in regulating vascular tone

    MARCKS mediates vascular contractility through regulating interactions between voltage-gated Ca2+ channels and PIP2.

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    Phosphatidylinositol 4,5-bisphosphate (PIP2) acts as substrate and unmodified ligand for Gq-protein-coupled receptor signalling in vascular smooth muscle cells (VSMCs) that is central for initiating contractility. The present work investigated how PIP2 might perform these two potentially conflicting roles by studying the effect of myristoylated alanine-rich C kinase substrate (MARCKS), a PIP2-binding protein, on vascular contractility in rat and mouse mesenteric arteries. Using wire myography, MANS peptide (MANS), a MARCKS inhibitor, produced robust contractions with a pharmacological profile suggesting a predominantly role for L-type (CaV1.2) voltage-gated Ca2+ channels (VGCC). Knockdown of MARCKS using morpholino oligonucleotides reduced contractions induced by MANS and stimulation of α1-adrenoceptors and thromboxane receptors with methoxamine (MO) and U46619 respectively. Immunocytochemistry and proximity ligation assays demonstrated that MARCKS and CaV1.2 proteins co-localise at the plasma membrane in unstimulated tissue, and that MANS and MO reduced these interactions and induced translocation of MARCKS from the plasma membrane to the cytosol. Dot-blots revealed greater PIP2 binding to MARCKS than CaV1.2 in unstimulated tissue, with this binding profile reversed following stimulation by MANS and MO. MANS evoked an increase in peak amplitude and shifted the activation curve to more negative membrane potentials of whole-cell voltage-gated Ca2+ currents, which were prevented by depleting PIP2 levels with wortmannin. This present study indicates for the first time that MARCKS is important regulating vascular contractility and suggests that disinhibition of MARCKS by MANS or vasoconstrictors may induce contraction through releasing PIP2 into the local environment where it increases voltage-gated Ca2+ channel activity

    Role of protease activated receptor-2 in lymph node metastasis of uterine cervical cancers

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    <p>Abstract</p> <p>Background</p> <p>Protease activated receptor-2 (PAR-2) has been implicated in cellular proliferation, invasion and metastasis in various tumors. Lymph node metastasis is an important patient prognostic factor for uterine cervical cancers. This prompted us to study the role of PAR-2 in lymph node metastasis of uterine cervical cancers.</p> <p>Methods</p> <p>Thirty patients underwent surgery for uterine cervical cancers. PAR-2 histoscores and mRNA levels were determined by immunohistochemistry and real-time reverse transcription-polymerase chain reaction, respectively. Patient prognosis was analyzed with a 48-month survival rate.</p> <p>Results</p> <p>PAR-2 histoscores and mRNA levels significantly (<it>P </it>< 0.05) increased in 12 of 30 metastatic lymph node lesions from the corresponding primary tumor. The 48-month survival rate of the 12 patients with increased PAR-2 levels in metastatic lymph nodes was 42%, while the rate of the other 18 patients with no change in PAR-2 levels was 82%, regardless of histopathological type.</p> <p>Conclusion</p> <p>PAR-2 might work on lymph node metastasis of uterine cervical cancers, and is considered to be a novel prognostic indicator for uterine cervical cancers.</p

    Coexpression of EphB4 and ephrinB2 in tumour advancement of ovarian cancers

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    EphB4 and ephrinB2 expressions in ovarian cancers were studied to analyse EphB4/ephrinB2 functions against clinical backgrounds. EphB4 and ephrinB2 were dominantly localised in ovarian cancer cells of all cases studied. Both the histoscores and mRNA levels of EphB4 and ephrinB2 significantly increased with clinical stages (I<II<III<IV, P<0.001) in ovarian cancers, although there was no significant difference in EphB4 and ephrinB2 histoscores or in mRNA levels according to histopathological types. EphB4 as well as ephrinB2 histoscores in cancer cells correlated with the corresponding mRNA levels in each case (EphB4, P<0.001; ephrinB2, P<0.001). The 24-month survival rates of the 36 patients with high EphB4 and ephrinB2 expression were poor (25 and 27%, respectively), while for the other 36 patients with low EphB4 and ephrinB2 expression, they were significantly higher (68 and 64%, respectively). Therefore, EphB4/ephrinB2 may function in tumour advancement and coexpression of the Eph/ephrin system may potentiate tumour progression leading to poor survival. Thus, EphB4/ephrinB2 can be recognised as a novel prognostic indicator in the primary tumours of ovarian cancers

    Comparative genomics of two jute species and insight into fibre biogenesis

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    Jute (Corchorus sp.) is one of the most important sources of natural fibre, covering ∼80% of global bast fibre production1. Only Corchorus olitorius and Corchorus capsularis are commercially cultivated, though there are more than 100 Corchorus species2 in the Malvaceae family. Here we describe high-quality draft genomes of these two species and their comparisons at the functional genomics level to support tailor-designed breeding. The assemblies cover 91.6% and 82.2% of the estimated genome sizes for C. olitorius and C. capsularis, respectively. In total, 37,031 C. olitorius and 30,096 C. capsularis genes are identified, and most of the genes are validated by cDNA and RNA-seq data. Analyses of clustered gene families and gene collinearity show that jute underwent shared whole-genome duplication ∼18.66 million years (Myr) ago prior to speciation. RNA expression analysis from isolated fibre cells reveals the key regulatory and structural genes involved in fibre formation. This work expands our understanding of the molecular basis of fibre formation laying the foundation for the genetic improvement of jute. Bast (phloem) fibres are obtained from the stem of the plants such as jute, flax, hemp, ramie and kenaf. The annual global production of jute generates a farm value of ∼US$2.3 billion1. The cultivated species of jute, C. olitorius and C. capsularis, are morphologically and physiologically distinct (Supplementary Fig. 1), and a combination of useful traits from these species into a single genotype is highly desirable3. However, interspecific hybridization is limited because of their cross-incompatibility4,5. To facilitate comparative functional genomics and to understand the molecular basis of bast fibre biogenesis, genomes of two popular jute cultivars C. olitorius var. O-4 and C. capsularis var. CVL-1 are sequenced and analysed

    Studies on autocatalytic deposition of ternary Ni-W-P alloys using nickel sulphamate bath

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    An attempt has been made to deposit ternary Ni-W-P coatings autocatalytically using nickel sulphamate and sodium tungstate as nickel and tungsten sources, respectively, and sodium hypophosphite as a reducing agent. These coatings were deposited using an alkaline citrate based bath and were compared with plain Ni-P coatings. Both deposits were characterized for their structure, morphology, crystallization behavior and microhardness. Results obtained from EDX analysis showed that binary Ni-P alloy contains 11.0 wt.% of phosphorus. Incorporation of tungsten (2.7 wt.%) had reduced the phosphorus content to about 3.5 wt.% in ternary Ni-W-P deposits. Apart from phosphorus and nickel contents, a trace of sulphur was noticed in ternary Ni-W-P deposit. Structural examination carried out by XRD studies revealed the presence of a broad peak with a calculated grain size of 1.2 nm for binary alloy, where as a sharp peak with a grain size of 10 nm is obtained for ternary Ni-W-P alloy. Optical micrographs of as-plated binary Ni-P alloys exhibited slightly nodular structure compared to coarse nodular structure of ternary Ni-W-P deposits. Etched metallographic cross-sections revealed a lamellar/banded structure in both deposits. Studies on phase transformation behavior carried out by DSC showed that the crystallization temperature for ternary alloys was higher compared to binary alloys. Calculated activation energies for Ni-P and Ni-W-P deposits were 229 and 289 kJ/mol, respectively. Microhardness measurements made on as-plated and heat-treated (400 amp;deg;C for 1 h) deposits showed higher hardness values for ternary Ni-W-P deposits compared to binary deposits

    Studies on autocatalytic deposition of ternary Nix2013;Wx2013;P alloys using nickel sulphamate bath

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    An attempt has been made to deposit ternary Nix2013;Wx2013;P coatings autocatalytically using nickel sulphamate and sodium tungstate as nickel and tungsten sources, respectively, and sodium hypophosphite as a reducing agent. These coatings were deposited using an alkaline citrate based bath and were compared with plain Nix2013;P coatings. Both deposits were characterized for their structure, morphology, crystallization behavior and microhardness. Results obtained from EDX analysis showed that binary Nix2013;P alloy contains 11.0 wt.% of phosphorus. Incorporation of tungsten (2.7 wt.%) had reduced the phosphorus content to about 3.5 wt.% in ternary Nix2013;Wx2013;P deposits. Apart from phosphorus and nickel contents, a trace of sulphur was noticed in ternary Nix2013;Wx2013;P deposit. Structural examination carried out by XRD studies revealed the presence of a broad peak with a calculated grain size of 1.2 nm for binary alloy, where as a sharp peak with a grain size of 10 nm is obtained for ternary Nix2013;Wx2013;P alloy. Optical micrographs of as-plated binary Nix2013;P alloys exhibited slightly nodular structure compared to coarse nodular structure of ternary Nix2013;Wx2013;P deposits. Etched metallographic cross-sections revealed a lamellar/banded structure in both deposits. Studies on phase transformation behavior carried out by DSC showed that the crystallization temperature for ternary alloys was higher compared to binary alloys. Calculated activation energies for Nix2013;P and Nix2013;Wx2013;P deposits were 229 and 289 kJ/mol, respectively. Microhardness measurements made on as-plated and heat-treated (400 xB0;C for 1 h) deposits showed higher hardness values for ternary Nix2013;Wx2013;P deposits compared to binary deposits

    Structure and phase transformation behavour of electroless NI-P alloys containing tin and tungsten

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    Autocatalytic ternary Ni-Sn-P, Ni-W-P and quaternary Ni-W-Sn-P films were prepared using alkaline citrate-based baths and compared with binary Ni-P coatings. Energy dispersive analysis of X-ray (EDAX) showed that binary Ni-P deposit contained 11.3 wt.% of phosphorus. Codeposition of tungsten in Ni-P matrix resulted in ternary Ni-W-P with 5 wt.% P and 7.8 wt.% of tungsten. Incorporation of tin led to ternary Ni-Sn-P deposit containing 0.4 wt.% Sn and 10.3 wt.% P. Presence of both sodium tungstate and sodium stannate in the basic bath had resulted in quaternary coating with 6.9 wt.% W, traces of Sn and 6.4 wt.% P. X-ray diffraction patterns of all the deposits revealed a single, broad peak which showed the nanocrystalline nature of the deposits. For the first time in related literature, the presence of a metastable phase Ni12P5 in ternary deposits is reported in the present study. Metallographic cross-sections of all the deposits revealed the banded/lamellar structure. Scanning electron microscopy (SEM) studies of the deposits showed smooth nodules for ternary deposits, but coarse and well-defined nodules for quaternary deposits. DSC studies of phase transformation behavior of the ternary Ni-Sn-P deposit revealed a single sharp exothermic peak at 365 xB0;C. However, ternary Ni-W-P and quaternary Ni-W-Sn-P deposits exhibited a low temperature peak at 300 xB0;C, a split type high temperature peak at 405 and 440 xB0;C and a very high temperature peak at 550 xB0; C. Higher activation energy values were obtained for W-based alloy deposits. Presence of W and Sn has helped to retain high microhardness values even at higher temperatures indicating an improved thermal stability

    Studies on electroless Ni-W-P and Ni-W-Cu-P alloy coatings using chloride-based bath13;

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    In the present investigation ternary electroless Ni-W-P alloy coatings were prepared using alkaline citrate-based bath. Nickel chloride and sodium tungstate were used as nickel and tungsten sources, respectively, and sodium hypophosphite was used as a reducing agent. Deposits were characterized for their structure, morphology, chemical composition and microhardness. A single peak was obtained in XRD for ternary Ni-W-P alloy. Addition of 3 mM of copper chloride in the bath has resulted in a very smooth quaternary Ni-W-Cu-P alloy. Also, codeposition of copper in ternary alloy has increased the peak sharpness and the calculated grain sizes for ternary and quaternary deposits are 2.5 and 8.8 nm, respectively. XPS studies show that in ternary Ni-W-P deposits from the present bath nearly 60 at.% of tungsten is present in the elemental form, Wlt;supgt;0lt;/supgt;, as compared to that from nickel chloride and sulphate additives bath in which Wlt;supgt;0lt;/supgt; state is only 27 at.%. Addition of copper chloride to the present bath has increased this elemental form by nearly 10 at.% in the quaternary deposit. SEM micrographs show that ternary alloy films are nodular whereas quaternary alloy films are smooth and nodule-free. Microhardness measurements show a marginal difference in the hardness between ternary and quaternary deposits. [All rights reserved Elsevier
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