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1.
Abstract The transduction mechanisms of P2 receptors have remained uncharacterized until recently. Data accumulated in the last few years demonstrate that, in many cell types, ATP induces a rise of cytoplasmic Ca2+, which often results from the direct coupling between P2 receptors and phospholipase C. 相似文献
2.
《Journal of receptor and signal transduction research》2013,33(1-4):121-132
AbstractATP exerts at least 2 actions on arterial endothelial cells: it stimulates the release of endothelium-derived relaxing factor, a still unidentified vasodilator, and of prostacyclin, a potent inhibitor of platelet aggregation. A study of agonist specificity indicates that these responses are mediated by P2-purinergic receptors. We have now demonstrated that in these cells, the P2-receptors are coupled to a phospholipase C hydrolysing phospha-tidylinositol-bisphosphate and that this coupling involves a pertussis toxin-sensitive GTP-binding regulatory protein. 相似文献
3.
G. Burnstock 《Nucleosides, nucleotides & nucleic acids》2013,32(5):917-930
Abstract The basis of the established subdivision of receptors for purines into P1-purinoceptors for adenosine and P2-purinoceptors for ATP and ADP is considered, as well as the proposals for subdivision of P1-purinoceptors into A1 and A2 subtypes and of ATP receptors into P2x-, P2y- P2z- and P2T-purinoceptor subtypes. The distribution and roles of these receptor subtypes in muscles, nerves and other tissues, including endothelial and epithelial cells, hepatocytes, blood cells, fibroblasts and astrocytes, are discussed. 相似文献
4.
《Cellular signalling》2014,26(7):1576-1588
The sphingosine-1-phosphate (S1P) type 1 receptor (S1P1R) is a novel therapeutic target in lymphocyte-mediated autoimmune diseases. S1P1 receptor desensitization caused by synthetic S1P1 receptor agonists prevents T-lymphocyte egress from secondary lymphoid organs into the circulation. The selective S1P1 receptor agonist ponesimod, which is in development for the treatment of autoimmune diseases, efficiently reduces peripheral lymphocyte counts and displays efficacy in animal models of autoimmune disease. Using ponesimod and the natural ligand S1P, we investigated the molecular mechanisms leading to different signaling, desensitization and trafficking behavior of S1P1 receptors. In recombinant S1P1 receptor-expressing cells, ponesimod and S1P triggered Gαi protein-mediated signaling and β-arrestin recruitment with comparable potency and efficiency, but only ponesimod efficiently induced intracellular receptor accumulation. In human umbilical vein endothelial cells (HUVEC), ponesimod and S1P triggered translocation of the endogenous S1P1 receptor to the Golgi compartment. However, only ponesimod treatment caused efficient surface receptor depletion, receptor accumulation in the Golgi and degradation. Impedance measurements in HUVEC showed that ponesimod induced only short-lived Gαi protein-mediated signaling followed by resistance to further stimulation, whereas S1P induced sustained Gαi protein-mediated signaling without desensitization. Inhibition of S1P lyase activity in HUVEC rendered S1P an efficient S1P1 receptor internalizing compound and abrogated S1P-mediated sustained signaling. This suggests that S1P lyase – by facilitating S1P1 receptor recycling – is essential for S1P-mediated sustained signaling, and that synthetic agonists are functional antagonists because they are not S1P lyase substrates. 相似文献
5.
《Journal of receptor and signal transduction research》2013,33(2):141-153
AbstractA canine limbic system preparation is utilized as a source of substance P receptor(s) to screen gradient RP-HPLC fractions for the presence of receptoractive-substance P activity, and to quantify endogenous receptoractive-substance p in biological extracts such as human tooth pulp. The binding characteristics, KD = 1.3 nM and Bmax = 11 fmol mg?1 protein, are similar to values obtained from receptors produced from other biological sources such as whole rat brain, minus cerebellum. 相似文献
6.
Katrin Sobel Katalin Menyhart Nina Killer Bérengère Renault Yasmina Bauer Rolf Studer Beat Steiner Martin H. Bolli Oliver Nayler John Gatfield 《The Journal of biological chemistry》2013,288(21):14839-14851
Synthetic sphingosine 1-phosphate receptor 1 modulators constitute a new class of drugs for the treatment of autoimmune diseases. Sphingosine 1-phosphate (S1P) signaling, however, is also involved in the development of fibrosis. Using normal human lung fibroblasts, we investigated the induction of fibrotic responses by the S1P receptor (S1PR) agonists S1P, FTY720-P, ponesimod, and SEW2871 and compared them with the responses induced by the known fibrotic mediator TGF-β1. In contrast to TGF-β1, S1PR agonists did not induce expression of the myofibroblast marker α-smooth muscle actin. However, TGF-β1, S1P, and FTY720-P caused robust stimulation of extracellular matrix (ECM) synthesis and increased pro-fibrotic marker gene expression including connective tissue growth factor. Ponesimod showed limited and SEW2871 showed no pro-fibrotic potential in these readouts. Analysis of pro-fibrotic signaling pathways showed that in contrast to TGF-β1, S1PR agonists did not activate Smad2/3 signaling but rather activated PI3K/Akt and ERK1/2 signaling to induce ECM synthesis. The strong induction of ECM synthesis by the nonselective agonists S1P and FTY720-P was due to the stimulation of S1P2 and S1P3 receptors, whereas the weaker induction of ECM synthesis at high concentrations of ponesimod was due to a low potency activation of S1P3 receptors. Finally, in normal human lung fibroblast-derived myofibroblasts that were generated by TGF-β1 pretreatment, S1P and FTY720-P were effective stimulators of ECM synthesis, whereas ponesimod was inactive, because of the down-regulation of S1P3R expression in myofibroblasts. These data demonstrate that S1PR agonists are pro-fibrotic via S1P2R and S1P3R stimulation using Smad-independent pathways. 相似文献
7.
Ryan M. Fryer Akalushi Muthukumarana Paul C. Harrison Suzanne Nodop Mazurek Rong Rhonda Chen Kyle E. Harrington Roger M. Dinallo Joshua C. Horan Lori Patnaude Louise K. Modis Glenn A. Reinhart 《PloS one》2012,7(12)
Sphingosine-1-phospate (S1P) and S1P receptor agonists elicit mechanism-based effects on cardiovascular function in vivo. Indeed, FTY720 (non-selective S1PX receptor agonist) produces modest hypertension in patients (2–3 mmHg in 1-yr trial) as well as acute bradycardia independent of changes in blood pressure. However, the precise receptor subtypes responsible is controversial, likely dependent upon the cardiovascular response in question (e.g. bradycardia, hypertension), and perhaps even species-dependent since functional differences in rodent, rabbit, and human have been suggested. Thus, we characterized the S1P receptor subtype specificity for each compound in vitro and, in vivo, the cardiovascular effects of FTY720 and the more selective S1P1,5 agonist, BAF312, were tested during acute i.v. infusion in anesthetized rats and after oral administration for 10 days in telemetry-instrumented conscious rats. Acute i.v. infusion of FTY720 (0.1, 0.3, 1.0 mg/kg/20 min) or BAF312 (0.5, 1.5, 5.0 mg/kg/20 min) elicited acute bradycardia in anesthetized rats demonstrating an S1P1 mediated mechanism-of-action. However, while FTY720 (0.5, 1.5, 5.0 mg/kg/d) elicited dose-dependent hypertension after multiple days of oral administration in rat at clinically relevant plasma concentrations (24-hr mean blood pressure = 8.4, 12.8, 16.2 mmHg above baseline vs. 3 mmHg in vehicle controls), BAF312 (0.3, 3.0, 30.0 mg/kg/d) had no significant effect on blood pressure at any dose tested suggesting that hypertension produced by FTY720 is mediated S1P3 receptors. In summary, in vitro selectivity results in combination with studies performed in anesthetized and conscious rats administered two clinically tested S1P agonists, FTY720 or BAF312, suggest that S1P1 receptors mediate bradycardia while hypertension is mediated by S1P3 receptor activation. 相似文献
8.
SANDRA SIEHLER DANILO GUERINI 《Journal of receptor and signal transduction research》2013,33(5-6):549-575
To elucidate the physiological function of sphingosine 1-phosphate receptors 1–3 (S1P1?3) we aimed to identify selective ligands for these GPCRs. S1P2 and S1P3 are coupled to Gq, and are, therefore, linked to the phospholipase C/IP3/calcium pathway. S1P1 is solely coupled to Gi and was artificially linked to calcium signaling by coexpression of Gα 16. The three receptors desensitized on challenge of cells with an agonist (i.e., agonists appeared as antagonists in a second calcium measurement). We screened a compound library for inhibitors of S1P-stimulated calcium signals, and we could identify agonists and antagonists with a single measurement. Agonism and antagonism were confirmed by recording compound-and S1P-induced calcium signals from the same assay well. For the three receptors, we found a reciprocal correlation of agonism and “apparent” antagonism of agonists. In addition, agonists indirectly discovered by this approach do not promote calcium mobilization through endogenous GPCRs. 相似文献
9.
Masao Fujimoto Akira Kuninaka Hiroshi Yoshino 《Bioscience, biotechnology, and biochemistry》2013,77(7):1121-1124
Properties of nuclease P1-malonogalactan complex (P1-MG) were compared with those of the polysaccharide-free nuclease P1. Significant difference was not observed between them in phosphomonoester splitting activity, but marked differences were observed in nucleolytic activity as follows: (1) The pH optima of P1-MG for RNA and heat-denatured DNA were lower than those of nuclease P1. (2) At lower than 0.001 of ionic strength, RNA and heat- denatured DNA were attacked hardly by P1-MG, but attacked well by nuclease P1. (3) The increase in hydrolysis rate of RNA or heat-denatured DNA with an elevation of temperature from 37°C to 70°C was not so marked in P1-MG as compared with nuclease P1. (4) P1-MG hydrolyzed polynucleotides, especially native DNA, much slower than nuclease P1.Influence of ionic strength, pH and temperature on the nucleolytic activity of nuclease P1-galactan (P1-G), which was prepared by demalonylating P1-MG enzymatically, was similar to that of nuclease P1, except that the activity of P1-G for native DNA was much lower than nuclease P1. 相似文献
10.
Candelore MR Wright MJ Tota LM Milligan J Shei GJ Bergstrom JD Mandala SM 《Biochemical and biophysical research communications》2002,297(3):600-606
It has been reported recently that the phosphorylated form of the immunomodulator FTY720 activates sphingosine 1-phosphate G protein-coupled receptors [1] and [2]. Therefore, understanding the biology of this new class of receptors will be important in clarifying the immunological function of bioactive lysosphingolipid ligands. The S1P4 receptor has generated interest due to its lymphoid tissue distribution. While the S1P4 receptor binds the prototypical ligand, S1P, a survey of other lysosphingolipids demonstrated that 4d-hydroxysphinganine 1-phosphate, more commonly known as phytosphingosine 1-phosphate (PhS1P), binds to S1P4 with higher affinity. Using radiolabeled S1P (S133P), the affinity of PhS1P for the S1P4 receptor is 1.6 nM, while that of S1P is nearly 50-fold lower (119±20 nM). Radiolabeled PhS1P proved to be superior to S133P in routine binding assays due to improved signal-to-noise ratio. The present study demonstrates the utility of a novel radiolabeled probe, PhS133P, for in vitro studies of the S1P4 receptor pharmacology. 相似文献
11.
《Gender Medicine》2012,9(1):21-32
BackgroundSex differences in the expression of the angiotensin (Ang) II receptors and angiotensin-converting enzyme 2 (ACE2) have been hypothesized to be a potential mechanism contributing to sex-specific differences in arterial pressure. Currently, sex differences in the expression of the angiotensin receptors and ACE2 remain undefined.ObjectivesThe aim of this study was to define the postnatal ontogeny of mRNA expression, from birth to adulthood, of the Ang II and Ang-(1-7) receptors and ACE2 in male and female rats.MethodsKidney and heart tissue was collected from male and female Sprague Dawley rats and snap-frozen at postnatal days (PNDs) 1, 30, 42, 70, and 110 (adult), and real-time polymerase chain reaction was performed to determine relative expression of the Ang II and Ang-(1-7) receptors (AT1aR, AT1bR, AT2R, and MasR) and ACE2.ResultsAll these components of the renin-angiotensin system (RAS) were detected in the kidney and left ventricle, although expression levels differed significantly between the sexes and across organs. Gene expression of most components of the RAS was high at birth and decreased with age in both sexes, except for ACE2 expression, which increased in the left ventricle with age (PAge < 0.001). Low levels of AT2R were observed in the ventricles in both sexes as adults. Most notably, AT2R expression was greatest in female kidneys and lowest in male kidneys compared with the left ventricle (PAge*Sex < 0.05). Interestingly, MasR expression in the female kidney was similar to the level of AT2R expression. Left ventricular MasR expression was greater than AT2R expression in both sexes but was not different between the sexes. The highest level of ACE2 expression was observed in adult female kidneys (PAS < 0.05).ConclusionsThe enhanced mRNA expression of the vasodilatory arm of the renal RAS (ACE2, AT2R) in females observed in the present study may contribute to sex differences in the regulation of arterial pressure and the incidence of cardiovascular disease in women. 相似文献
12.
Hideru Obinata Sarah Gutkind Jeremiah Stitham Toshiaki Okuno Takehiko Yokomizo John Hwa Timothy Hla 《Journal of lipid research》2014,55(12):2665-2675
Sphingosine 1-phosphate receptor 1 (S1P1), an abundantly-expressed G protein-coupled receptor which regulates key vascular and immune responses, is a therapeutic target in autoimmune diseases. Fingolimod/Gilenya (FTY720), an oral medication for relapsing-remitting multiple sclerosis, targets S1P1 receptors on immune and neural cells to suppress neuroinflammation. However, suppression of endothelial S1P1 receptors is associated with cardiac and vascular adverse effects. Here we report the genetic variations of the S1P1 coding region from exon sequencing of >12,000 individuals and their functional consequences. We conducted functional analyses of 14 nonsynonymous single nucleotide polymorphisms (SNPs) of the S1PR1 gene. One SNP mutant (Arg120 to Pro) failed to transmit sphingosine 1-phosphate (S1P)-induced intracellular signals such as calcium increase and activation of p44/42 MAPK and Akt. Two other mutants (Ile45 to Thr and Gly305 to Cys) showed normal intracellular signals but impaired S1P-induced endocytosis, which made the receptor resistant to FTY720-induced degradation. Another SNP mutant (Arg13 to Gly) demonstrated protection from coronary artery disease in a high cardiovascular risk population. Individuals with this mutation showed a significantly lower percentage of multi-vessel coronary obstruction in a risk factor-matched case-control study. This study suggests that individual genetic variations of S1P1 can influence receptor function and, therefore, infer differential disease risks and interaction with S1P1-targeted therapeutics. 相似文献
13.
Malchinkhuu E Sato K Maehama T Mogi C Tomura H Ishiuchi S Yoshimoto Y Kurose H Okajima F 《Biochemical and biophysical research communications》2008,366(4):963-968
Sphingosine 1-phosphate (S1P) induced the inhibition of glioma cell migration. Here, we characterized the signaling mechanisms involved in the inhibitory action by S1P. In human GNS-3314 glioblastoma cells, the S1P-induced inhibition of cell migration was associated with activation of RhoA and suppression of Rac1. The inhibitory action of S1P was recovered by a small interference RNA specific to S1P2 receptor, a carboxyl-terminal region of Gα12 or Gα13, an RGS domain of p115RhoGEF, and a dominant-negative mutant of RhoA. The inhibitory action of S1P through S1P2 receptors was also observed in both U87MG glioblastoma and 1321N1 astrocytoma cells, which have no protein expression of a phosphatase and tensin homolog deleted on chromosome 10 (PTEN). These results suggest that S1P2 receptors/G12/13-proteins/Rho signaling pathways mediate S1P-induced inhibition of glioma cell migration. However, PTEN, recently postulated as an indispensable molecule for the inhibition of cell migration, may not be critical for the S1P2 receptor-mediated action in glioma cells. 相似文献
14.
摘要 目的:观察血清分泌型卷曲相关蛋白1(SFRP1)、分泌型卷曲相关蛋白5(SFRP5)、1-磷酸鞘氨醇(S1P)、T细胞免疫球蛋白域及黏蛋白域蛋白4(TIM4)与成人支气管哮喘急性发作期患者肺功能、气道炎症和治疗后再次急性复发的关系。方法:选择火箭军特色医学中心2016年7月~2020年8月期间收治的120例成人支气管哮喘患者,其中47例缓解期患者纳为缓解组,73例急性发作期患者纳为发作组。对比发作组、缓解组血清S1P、SFRP1、TIM4、SFRP5水平、肺功能[第1秒用力呼气容积(FEV1)、用力肺活量(FVC)、FEV1/FVC]、气道炎症[血清总免疫球蛋白E(IgE)、痰嗜酸粒细胞、呼出气一氧化氮(FeNO)、血嗜酸粒细胞],治疗结束后以门诊复查或电话的形式进行随访1年,根据1年内是否再次急性复发分组,分为复发组和未复发组,对比复发组和未复发组的血清S1P、SFRP1、TIM4、SFRP5水平。结果:发作组的S1P、SFRP1、TIM4高于缓解组,SFRP5低于缓解组(P<0.05)。发作组的FEV1、FVC、FEV1/FVC低于缓解组(P<0.05)。发作组的血清总IgE、嗜酸粒细胞、FeNO、血嗜酸粒细胞高于缓解组(P<0.05)。Pearson相关性分析结果显示,S1P、SFRP1、TIM4与FEV1、FVC、FEV1/FVC呈负相关(P<0.05),而与血清总IgE、嗜酸粒细胞、FeNO、血嗜酸粒细胞均呈正相关(P<0.05)。SFRP5与FEV1、FVC、FEV1/FVC呈正相关(P<0.05),而与血清总IgE、嗜酸粒细胞、FeNO、血嗜酸粒细胞均呈负相关(P<0.05)。复发组的S1P、SFRP1、TIM4高于未复发组,SFRP5低于未复发组(P<0.05)。结论:成人支气管哮喘急性发作期患者S1P、SFRP1、TIM4水平异常升高,SFRP5异常降低,且与肺功能、气道炎症、再次急性复发均有一定关系。 相似文献
15.
BackgroundGlial cells such as astrocytes and microglia play an important role in the central nervous system via communication between these glial cells. Activated microglia can exhibit either the inflammatory M1 phenotype or the anti-inflammatory M2 phenotype, which influences astrocytic neuroprotective functions, including engulfment of cell debris. Recently, extracellular zinc has been shown to promote the inflammatory M1 phenotype in microglia through intracellular zinc accumulation and reactive oxygen species (ROS) generation.PurposeHere, we investigated whether the zinc-enhanced inflammatory M1 phenotype of microglia affects the astrocytic engulfing activity.MethodsEngulfing activity was assessed in astrocytes treated with microglial-conditioned medium (MCM) from lipopolysaccharide (LPS)-activated or from ZnCl2-pretreated LPS-activated M1 microglia. The effect of zinc on microglia phenotype was also validated using the zinc chelator N,N,N’,N’-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) and the ROS scavenger Trolox.ResultsAlthough treatment of astrocytes with LPS showed no significant effect on the engulfing activity, MCM from LPS-induced M1 microglia increased the beads uptake by astrocytes. This increased uptake activity was suppressed when MCM from LPS-induced M1 microglia pretreated with ZnCl2 was applied to astrocytes, which was further abolished by the intracellular zinc chelator TPEN and the ROS scavenger Trolox. In addition, expression of P2×7 receptors (P2×7R) was increased in astrocytes treated with MCM derived from M1 microglia but not in the M1 microglia pretreated with ZnCl2.ConclusionThese findings suggest that zinc pre-treatment abolishes the ability of LPS-induced M1 microglia to increase the engulfing activity in astrocytes via alteration of astrocytic P2×7R. 相似文献
16.
Masao Fujimoto Akira Kuninaka Hiroshi Yoshino 《Bioscience, biotechnology, and biochemistry》2013,77(7):1111-1119
Nuclease P1 from Penicillium citrinum was found to be produced in a form of complex with malonogalactan (a galactan, 1, 5-β-galactofuranoside polymer esterfied with malonic acid at position 3) in the culture on wheat bran. Neither nuclease P1-malonogalactan complex nor malonogalactan was produced in a liquid medium. Nuclease P1-malonogalactan complexes, P1-MG I, II, and III were purified from an aqueous extract of the culture on wheat bran. The most anionic complex, P1-MG III, was composed of the protein, carbohydrate and malonic acid in the ratio of 1: 2.6: 0.5 (w/w). The complex was not dissociated by purification procedures including fractionations with acetone and ammonium sulfate, gel filtration and DEAE-cellulose chromatography. A malonogalactan-specific carboxylesterase was found in culture of the same mold on wheat bran. Nuclease P1-malonogalactan was demalonylated by the esterase to yield nuclease P1-galactan. The binding of nuclease P1 to galactan was rather loose so that nuclease P1-galactan complex was partially dissociated by DEAE-cellulose chromatography. Attempt to reconstitute the complex from nuclease P1 and malonogalactan upon mixing was unsuccessful. Exogenously supplemented nuclease P1 did not associate with malonogalactan in the growing culture on wheat bran, either.Several extracellular enzymes such as RNase, β-galactosidase and protease were also found in a form of complex with malonogalactan in the culture on wheat bran. 相似文献
17.
Flores RV Hernández-Pérez MG Aquino E Garrad RC Weisman GA Gonzalez FA 《Molecular and cellular biochemistry》2005,280(1-2):35-45
Purification of HA-tagged P2Y2 receptors from transfected human 1321N1 astrocytoma cells yielded a protein with a molecular size determined by SDS-PAGE
to be in the range of 57–76 kDa, which is typical of membrane glycoproteins with heterogeneous complex glycosylation. The
protein phosphatase inhibitor, okadaic acid, attenuated the recovery of receptor activity from the agonist-induced desensitized
state, suggesting a role for P2Y2 receptor phosphorylation in desensitization. Isolation of HA-tagged P2Y2 nucleotide receptors from metabolically [32P]-labelled cells indicated a (3.8 ± 0.2)-fold increase in the [32P]-content of the receptor after 15 min of treatment with 100 μM UTP, as compared to immunoprecipitated receptors from untreated
control cells. Receptor sequestration studies indicated that ∼40% of the surface receptors were internalized after a 15-min
stimulation with 100 μM UTP. Point mutation of three potential GRK and PKC phosphorylation sites in the third intracellular
loop and C-terminal tail of the P2Y2 receptor (namely, S243A, T344A, and S356A) extinguished agonist-induced receptor phosphorylation, caused a marked reduction
in the efficacy of UTP to desensitize P2Y2 receptor signalling to intracellular calcium mobilization, and impaired agonist-induced receptor internalization. Activation
of PKC isoforms with phorbol 12-myristate 13-acetate that caused heterologous receptor desensitization did not increase the
level of P2Y2 receptor phosphorylation. Our results indicate a role for receptor phosphorylation by phorbol-insensitive protein kinases
in agonist-induced desensitization of the P2Y2 nucleotide receptor. (Mol Cell Biochem xxx: 35–45, 2005) 相似文献
18.
In this study, the distribution patterns of P2Y1, P2Y2 P2Y4, P2Y6, P2Y12, and P2Y13 receptors in the anterior pituitary cells of rat were studied with double-labeling immunofluorescence and Western blot. The
results showed that P2Y receptors were widely expressed in the anterior pituitary. P2Y1 and P2Y4 receptors were found to be expressed in the majority of gonadotrophs and thyrotrophs, P2Y2 receptors were expressed in a small subpopulation of lactotrophs and almost all the folliculo-stellate cells, that were also
stained with S100 protein immunoreactivity. P2Y6 receptors were expressed in macrophages. P2Y13 receptors were expressed in a small subpopulation of cells in the rat anterior pituitary, the identity of which needs to
be clarified. P2Y1 and P2Y4 receptors are co-expressed in some gonadotrophs and thyrotrophs. Corticotrophs and somatotrophs were found not to express
P2Y receptors in this study. FSH and TSH were shown to coexist in the same endocrine cells in rat anterior pituitary. The
present data suggests that purines and/or pyrimidines could be involved in regulating the functions of gonadotrophs and thyrotrophs
via P2Y1 and P2Y4 receptors, some lactotrophs via P2Y2 receptors, and folliculo-stellate cells via P2Y2 receptors in the rat anterior pituitary. 相似文献
19.
Adan Oviedo Camelia Herman Alaine Knipes Caitlin M. Worrell LeAnne M. Fox Luccene Desir Carl Fayette Alain Javel Franck Monestime Kimberly E. Mace Michelle A. Chang Jean F. Lemoine Kimberly Won Venkatachalam Udhayakumar Eric Rogier 《PLoS neglected tropical diseases》2022,16(1)
BackgroundEstimation of malaria prevalence in very low transmission settings is difficult by even the most advanced diagnostic tests. Antibodies against malaria antigens provide an indicator of active or past exposure to these parasites. The prominent malaria species within Haiti is Plasmodium falciparum, but P. vivax and P. malariae infections are also known to be endemic.Methodology/Principal findingsFrom 2014–2016, 28,681 Haitian children were enrolled in school-based serosurveys and were asked to provide a blood sample for detection of antibodies against multiple infectious diseases. IgG against the P. falciparum, P. vivax, and P. malariae merozoite surface protein 19kD subunit (MSP119) antigens was detected by a multiplex bead assay (MBA). A subset of samples was also tested for Plasmodium DNA by PCR assays, and for Plasmodium antigens by a multiplex antigen detection assay. Geospatial clustering of high seroprevalence areas for P. vivax and P. malariae antigens was assessed by both Ripley’s K-function and Kulldorff’s spatial scan statistic. Of 21,719 children enrolled in 680 schools in Haiti who provided samples to assay for IgG against PmMSP119, 278 (1.27%) were seropositive. Of 24,559 children enrolled in 788 schools providing samples for PvMSP119 serology, 113 (0.46%) were seropositive. Two significant clusters of seropositivity were identified throughout the country for P. malariae exposure, and two identified for P. vivax. No samples were found to be positive for Plasmodium DNA or antigens.Conclusions/SignificanceFrom school-based surveys conducted from 2014 to 2016, very few Haitian children had evidence of exposure to P. vivax or P. malariae, with no children testing positive for active infection. Spatial scan statistics identified non-overlapping areas of the country with higher seroprevalence for these two malarias. Serological data provides useful information of exposure to very low endemic malaria species in a population that is unlikely to present to clinics with symptomatic infections. 相似文献
20.
《Journal of receptor and signal transduction research》2013,33(1-3):115-126
AbstractTwo types of ligand-gated ion channels were expressed with the Semliki Forest virus (SFV) expression system.The cDNAs for mouse serotonin 5-HT3 receptor and rat and human purinoreceptor P2x subtypes were introduced into the pSFV1 vector. In vitro transcribed RNAs were coelectroporated with pSFV-Helper2 RNA into BHK cells, where in vivo packaging resulted in high titer SFV-5-HT3 and SFV-P2x virus stocks. Infection of BHK, CHO and RJN cells resulted in high-level expression of recombinant receptors. Saturation binding analysis indicated the presence of more than 3 × 106 5-HT3 receptors per cell. Binding studies on isolated membranes yielded from 10 to 60 pmol of either 5-HT3 or P2x receptor per mg protein. Functional responses to the P2x receptors were demonstrated in SFV-infected CHO cells by Ca2+ mobilization or by 45Ca2+ influx. High amplitude electrophysiological responses were also detected for both SFV-5-HT3 and SFV-P2x infected CHO cells in whole-cell patch clamp recordings. To facilitate the purification procedure of SFV-expressed recombinant receptors a histidine tag was introduced at the C-terminus of the 5-HT3 receptor. This 5-HT3His receptor showed high levels of expression, specific binding and high amplitude electrophysiological responses. For large scale expression the BHK cells were adapted to suspension culture and were efficiently infected in a 11.5 liter fermentor culture with SFV-5-HT3His resulting in high-level expression, 52 pmol receptor per mg protein corresponding to 3.2 × 106 receptors per cell. 相似文献