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Ji X, Pushalkar S, Li Y, Glickman R, Fleisher K, Saxena D. Antibiotic effects on bacterial profile in osteonecrosis of the jaw. Oral Dis 2012; 18:85-95. [PMID: 21883710 PMCID: PMC3232327 DOI: 10.1111/j.1601-0825.2011.01848.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Oral infection is considered to play a critical role in the pathogenesis of bisphosphonate-related osteonecrosis of the jaw (BRONJ), and antibiotic therapy has become a mainstay of BRONJ therapy. This study was aimed to investigate the effect of antibiotics on bacterial diversity in BRONJ tissues. MATERIALS AND METHODS The bacterial profile from soft tissues associated with the BRONJ lesion was determined using 16S rRNA-based denaturing gradient gel electrophoresis (DGGE) and sequencing. Twenty BRONJ subjects classified as stage 0-2 were enrolled in this study, and patient groups were divided into an antibiotic cohort (n=10) treated with systemic antibiotic and a non-antibiotic cohort (n=10) with no prior antibiotic therapy. RESULTS The DGGE fingerprints indicated no significant differences in bacterial diversity of BRONJ tissue samples. Patients on antibiotics had higher relative abundance of phylum Firmicutes with bacterial species, Streptococcus intermedius, Lactobacillus gasseri, Mogibacterium timidum, and Solobacterium moorei, whereas patients without antibiotics had greater amounts of Parvimonas micra and Streptococcus anginosus. Thirty percent of bacterial populations were uncultured (yet-to be cultured) phylotypes. CONCLUSION This study using limited sample size indicated that oral antibiotic therapy may have a limited efficacy on the bacterial population associated with BRONJ lesions.
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Ji X, Kong J, Liebhaber SA. An RNA-protein complex links enhanced nuclear 3' processing with cytoplasmic mRNA stabilization. EMBO J 2011; 30:2622-33. [PMID: 21623344 DOI: 10.1038/emboj.2011.171] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 04/19/2011] [Indexed: 01/09/2023] Open
Abstract
Post-transcriptional controls are critical to gene regulation. These controls are frequently based on sequence-specific binding of trans-acting proteins to cis-acting motifs on target RNAs. Prior studies have revealed that the KH-domain protein, αCP, binds to a 3' UTR C-rich motif of hα-globin mRNA and contributes to its cytoplasmic stability. Here, we report that this 3' UTR αCP complex regulates the production of mature α-globin mRNA by enhancing 3' processing of the hα-globin transcript. We go on to demonstrate that this nuclear activity reflects enhancement of both the cleavage and the polyadenylation reactions and that αCP interacts in vivo with core components of the 3' processing complex. Consistent with its nuclear processing activity, our studies reveal that αCP assembles co-transcriptionally at the hα-globin chromatin locus and that this loading is selectively enriched at the 3' terminus of the gene. The demonstrated linkage of nuclear processing with cytoplasmic stabilization via a common RNA-protein complex establishes a basis for integration of sequential controls critical to robust and sustained expression of a target mRNA.
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Ji X, Zhong Y, Zhou Y, Zhou F, Zhang G, Chen G, Deng D, Liu H, Zhang J, Xie C. Neoadjuvant chemotherapy and prognostic subgroups defined by survival benefit in patients with locoregionally advanced nasopharyngeal carcinoma. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.5536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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154
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Botteman M, Stephens J, Snedecor SJ, Ji X, Hussein M, Coombs J. Long-term estimate of quality-adjusted life expectancy for nilotinib and imatinib as first-line treatment for newly diagnosed patients with Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia in the chronic phase (CML-CP). J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.6570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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155
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Ovanfors A, Stephens J, Snedecor SJ, Patel D, Ji X, Carpiuc KT, Coombs J, Botteman M. Cost-effectiveness of nilotinib versus imatinib as first-line treatment for newly diagnosed patients with Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia in the chronic phase (CML-CP): Swedish perspective. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.6572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Zhang Z, Xu D, Shen M, Wu D, Chen Z, Ji X, Li F, Xu Y. Degradation of surfactant wastewater under microwave irradiation in the presence of activated carbon assisted with nano-sized TiO2 or nano-sized ZnO. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2011; 63:424-431. [PMID: 21278463 DOI: 10.2166/wst.2011.238] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
An improved method treating surfactant wastewater by the addition of semiconductor material such as nano-sized TiO2 or ZnO to activated carbon (AC) with microwave (MW) irradiation was proposed so as to assist efficient degradation of organic pollutants. A series of degradation experiments of sodium dodecyl benzene sulfonate (SDBS) were carried out under MW irradiation in the presence of AC/TiO2 or AC/ZnO. The influences of catalyst dose, irradiation time, initial SDBS concentration and solution acidity on the degradation were assessed in detail. The results showed that the addition of TiO2 or ZnO obviously promoted the degradation and AC/TiO2 system displayed higher catalytic activity under MW irradiation. Thus the method of MW irradiation with AC/TiO2 or AC/ZnO revealed many advantages of rapid degradation rate, short irradiation time, low cost, no residual intermediates and no secondary pollution in applications.
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Song Y, Peng X, Xie H, Liu X, Bao L, Zhou Z, Cao L, Xu T, Ji X, Peng Y, Zhu N, Zhang P, Wu J, Wang S, Wang X, Hu J, Xie C, Chen J, Luo G, Yao D, Gao D, Gong X, Fu P, Li J. Plasma facing components of EAST. FUSION ENGINEERING AND DESIGN 2010. [DOI: 10.1016/j.fusengdes.2010.09.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Gan X, Luo Y, Ling F, Ji X, Chen J, Ding Y. Outcome in acute stroke with different intra-arterial infusion rate of urokinase on thrombolysis. Interv Neuroradiol 2010; 16:290-6. [PMID: 20977863 DOI: 10.1177/159101991001600311] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Accepted: 07/03/2010] [Indexed: 12/18/2022] Open
Abstract
Intra-arterial infusion of urokinase (UK) has been widely used. However, the optimal infusion rate of the reagent has never been determined. This was investigated in the acute stage of middle cerebral artery (MCA) embolism in the present study. Sprague Dawley male rats (n=43) were randomly divided into sham-operation and five ischemic groups with urokinase administration at different infusion rates or without urokinase administration. Ischemia was induced with MCA embolism. Two hours after embolism, total urokinase (urokinase, 170,000U/kg) was given in groups A,B,C and D (n=8 each) at different rates: 1,000 U (0.03 ml/min) per minute, 4,000U (0.12 ml/min), 10,000U (0.30 ml/min), and 16,000U (0.48 ml/min), respectively. Group E received normal saline at a rate of 0.48 ml/min. The sham-operation group (no embolism) received urokinase at (170,000U/kg, 1.5 ml, 16,000 U/min). During ischemia and thrombolysis, regional cerebral blood flow (CBF) was monitored by laser Doppler flowmetry. The neurological deficits, infarct volumes and mortalities in each group were determined. The CBF in ischemic hemisphere were significantly (p<0.05) decreased after embolism in groups A∼E at similar levels (27.32±8.20% to 34.71±6.84%). After different treatments, in group B 4,000U/min infusion of UK induced the best reperfusion, the least neurological deficits and infarct volume, as well as the least mortality and lowest incidence of hemorrhage. The effect of intra-artery thrombolysis of urokinase was related to the infusion rate. Our study demonstrated an optimal infusion rate at 4,000U/min, suggesting relatively low levels of infusion are better able to improve brain reperfusion and reduce brain injury after stroke.
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Qiu J, Gao H, Zhao S, Wang Y, Ji X, You B, Liu X. e0708 IGFBP-7 contributes to vascular remolding during hypertension development in ouabain-induced hypertensive rats. BRITISH HEART JOURNAL 2010. [DOI: 10.1136/hrt.2010.208967.708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Cheng X, Cao P, Ji X, Lu W, Cai X, Hu C, Wang Z, Zhang S. Antitumour response of a double mutant of staphylococcal enterotoxin C2 with the decreased affinity for MHC class II molecule. Scand J Immunol 2010; 71:169-75. [PMID: 20415782 DOI: 10.1111/j.1365-3083.2009.02359.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Staphylococcal enterotoxin C2 (SEC2) is one of the most potent known activators of human T lymphocytes, and recombinant SEC2 shows promising clinical values, but SEC2 can cause food poisoning and toxic shock syndrome in vivo. In this study, site-directed mutagenesis has been used to introduce alanine substitutions at Phe144 and Leu45 in the molecule. The mutant genes were cloned and expressed, and the corresponding proteins were purified by nickel agarose affinity chromatography. We found that the SEC2 mutant proteins could stimulate the proliferation of human peripheral blood lymphocytes and inhibit the growth of tumour cells as native SEC2. Furthermore, flow cytometry assay showed that mSEC2(F44A, L45A) drastically reduced the ability of the toxin to bind to MHC class II. Physiological parameters revealed that mSEC2(F44A, L45A) reduced significantly rat temperature compared with native SEC2 in vivo. Our results clearly suggest that this genetically modified SEC2 protein is less toxic and justifies its further development as a new, safer antitumour superantigen to prevent SEC2 intoxication.
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Ji X, Le Bihan O, Ramalho O, Mandin C, D'Anna B, Martinon L, Nicolas M, Bard D, Pairon JC. Characterization of particles emitted by incense burning in an experimental house. INDOOR AIR 2010; 20:147-158. [PMID: 20409193 DOI: 10.1111/j.1600-0668.2009.00634.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The potential health effects of fine and ultrafine particles are of increasing concern. A better understanding of particle characteristics and dispersion behavior is needed. This study aims at characterizing spatial and temporal variations in fine and ultrafine particle dispersion after emission from a model source in an experimental house. Particles emitted by an incense stick burning for 15 min were characterized. Number concentration, specific surface area and mass were measured. Partial chemical analysis of particles was also realized. Near the burning incense stick, the maximum concentration was 25,500 particles/cm(3); the indoor PM(2.5) concentration reached 197 microg/m(3), and the specific surface area concentration was 180 microm(2)/cm(3). The estimated incense smoke density was 1.1 g/cm(3). Time of Flight Aerosol Mass Spectrometer measurements indicated that the organic fraction was predominant in the aerosol mass detected, and other minor components identified were K(+), NO(3)(-), and Cl(-). The combustion of an incense stick in the living room was associated with significant modifications of the concentrations of particles measured in the different rooms of the house. This demonstration of pollution by particle dispersion by a model source of moderate intensity may have significant implications in terms of assessment of indoor exposure to such particles. Practical Implications The particles emitted in a domestic environment by a source of moderate intensity such as burning incense disperse throughout the house, even in rooms with closed doors and in rooms as far away as the next floor. This dispersion has significant implications in terms of evaluating human indoor exposure to fine and ultrafine particles.
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Peng C, Huang H, Ji X, Liu X, Ren L, Yu W, You J, Lu J. Effects of n-Hexadecane Concentration and a Two-Stage Oxygen Supply Control Strategy on Arachidonic Acid Production by Mortierella Alpina ME-1. Chem Eng Technol 2010. [DOI: 10.1002/ceat.200900413] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Liebelt B, Papapetrou P, Ali A, Guo M, Ji X, Peng C, Rogers R, Curry A, Jimenez D, Ding Y. Exercise preconditioning reduces neuronal apoptosis in stroke by up-regulating heat shock protein-70 (heat shock protein-72) and extracellular-signal-regulated-kinase 1/2. Neuroscience 2010; 166:1091-100. [PMID: 20083167 DOI: 10.1016/j.neuroscience.2009.12.067] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 12/24/2009] [Accepted: 12/29/2009] [Indexed: 01/03/2023]
Abstract
Exercise preconditioning induces neuroprotection after stroke. We investigated the beneficial role of heat shock protein-70 (HSP-70) and phosphorylated extracellular-signal-regulated-kinase 1/2 (pERK 1/2), as they pertain to reducing apoptosis and their influence on Bcl-x(L), Bax, and apoptosis-inducing factor (AIF) in rats subjected to ischemia and reperfusion. Adult male Sprague-Dawley rats were subjected to 30 min of exercise on a treadmill for 1, 2, or 3 weeks. Stroke was induced by a 2-h middle cerebral artery (MCA) occlusion using an intraluminal filament. Protein levels of HSP-70, pERK 1/2, Bcl-x(L), Bax, and AIF were analyzed using Western blot. Neuroprotection was based on levels of apoptosis (TUNEL) and infarct volume (Nissl staining). Immunocytochemistry was used for cellular expression of HSP-70 and pERK 1/2. Significant (P<0.05) up-regulation of HSP-70 and pERK 1/2 after 3 weeks of exercise coincided with significant (P<0.05) reduction in neuronal apoptosis and brain infarct volume. Inhibition of either one of these two factors showed a significant (P<0.05) reversal in the neuroprotection. Bax and AIF were down-regulated, while levels of Bcl-x(L) were up-regulated in response to stroke after exercise. Inhibiting HSP-70 or pERK 1/2 reversed this resultant increase or decrease. Our results indicate that exercise diminishes neuronal injury in stroke by up-regulating HSP-70 and ERK 1/2.
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Pabbidi MR, Ji X, Samarel AM, Lipsius SL. Laminin enhances beta(2)-adrenergic receptor stimulation of L-type Ca(2+) current via cytosolic phospholipase A(2) signalling in cat atrial myocytes. J Physiol 2009; 587:4785-97. [PMID: 19703961 DOI: 10.1113/jphysiol.2009.179226] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We previously reported that attachment of atrial myocytes to the extracellular matrix protein laminin (LMN), decreases adenylate cyclase (AC)/cAMP and increases beta(2)-adrenergic receptor (AR) stimulation of L-type Ca(2+) current (I(Ca,L)). This study therefore sought to determine whether LMN enhances beta(2)-AR signalling via a cAMP-independent mechanism, i.e. cytosolic phospholipase A(2) (cPLA(2)) signalling. Studies were performed on acutely isolated atrial myocytes plated on uncoated coverslips (LMN) or coverslips coated with LMN (+LMN). As previously reported, 0.1 microm zinterol (zint-beta(2)-AR) stimulation of I(Ca,L) was larger in +LMN than LMN myocytes. In +LMN myocytes, zint-beta(2)-AR stimulation of I(Ca,L) was inhibited by inhibition of cPLA(2) by arachidonyltrifluoromethyl ketone (AACOCF(3); 10 microm), inhibition of G(i) by pertussis toxin and chelation of intracellular Ca(2+) by 10 microm BAPTA-AM. In contrast to zinterol, stimulation of I(Ca,L) by fenoterol (fen-beta(2)-AR), a beta(2)-AR agonist that acts exclusively via G(s) signalling, was smaller in +LMN than LMN myocytes. Arachidonic acid (AA; 5 microm) stimulated I(Ca,L) to a similar extent in LMN and +LMN myocytes. Inhibition of cAMP-dependent protein kinase A (cAMP/PKA) by either 5 mum H89 or 1 microm KT5720 in LMN myocytes mimicked the effects of +LMN myocytes to enhance zint-beta(2)-AR stimulation of I(Ca,L), which was blocked by 10 microm AACOCF(3). In contrast, H89 inhibited fen-beta(2)-AR stimulation of I(Ca,L), which was unchanged by AACOCF(3). Inhibition of ERK1/2 by 1 microm U0126 inhibited zint-beta(2)-AR stimulation of I(Ca,L) in +LMN myocytes and LMN myocytes in which cAMP/PKA was inhibited by KT5720. In LMN myocytes, cytochalasin D prevented inhibition of cAMP/PKA from enhancing zint-beta(2)-AR stimulation of I(Ca,L). We conclude that LMN enhances zint-beta(2)-AR stimulation of I(Ca,L) via G(i)/ERK1/2/cPLA(2)/AA signalling which is activated by concomitant inhibition of cAMP/PKA signalling and dependent on the actin cytoskeleton. These findings provide new insight into the cellular mechanisms by which the extracellular matrix can remodel beta(2)-AR signalling in atrial muscle.
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Zhang X, Ji X, Luo Y, Liu D, Guo L, Wu H, Miao Z, Zhu F, Jiao L, Ding Y, Ling F. Intra-arterial thrombolysis for acute central retinal artery occlusion. Neurol Res 2009; 31:385-9. [PMID: 19508824 DOI: 10.1179/174313209x444008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE In this study, we aimed at exploring the effect and safety of local intra-arterial thrombolysis on acute central retinal artery occlusion. METHODS Retrospective data analysis of 49 consecutive acute central retinal occlusion patients was performed. All the patients were treated with urokinase perfusion through the ophthalmology artery within the first 6 hours after central retinal artery occlusion attack. Conventional treatments including intra-ocular pressure decreasing, microcirculation improvement, neuroprotection and antiplatelet aggregation were conducted. The visual acuity (with International Snellen Chart) and field of vision were detected after thrombolysis. The complications and adverse events were observed. RESULTS Recanalization was found in 71% of patients. The visual acuity improvement was greater in the recanalization group (n=35) than in the non-recanalization group (n=14). The averaged visual acuity was 0.15+/-0.02, 0.25+/-0.03 and 0.4+/-0.05 after 2, 28 days and 6 months, respectively. Of the patients, 24.5% regained >0.6 of visual acuity, and the visual field deficit was less than 30% in 34.7% of patients after 28 days. Six months later, 36.7% patients regained visual acuity of >0.6, and the field deficit was less than 30% in 44.9% of patients. The difference between visual acuity in recanalization (0.6+/-0.04) and non-recanalization (0.002+/-0.0012) patients after 6 months after thrombolysis was significant (p>0.05). CONCLUSIONS Intra-arterial thrombolysis could obviously improve the short- and long-term visual function for patients with acute central retinal artery occlusion within 6 hours of symptom onset.
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Huang H, Fan S, Ji X, Zhang Y, Bao F, Zhang G. Recombinant Human Erythropoietin Protects against Experimental Spinal Cord Trauma Injury by Regulating Expression of the Proteins MKP-1 and p-ERK. J Int Med Res 2009; 37:511-9. [PMID: 19383246 DOI: 10.1177/147323000903700227] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The present study explored the tissue-protective effect of erythropoietin in rats after experimental spinal cord injury (SCI) produced by dropping a weight onto surgically exposed spinal cord. Sixty rats were randomized to sham operation (spinal cord exposure; control), SCI plus intraperitoneal saline injection, or SCI plus intraperitoneal erythropoietin injection. Locomotor function was evaluated with Basso, Beattie and Bresnahan scores 1 day (24 h) and 7 days later, and rats were then killed for analysis of lesion site tissue. Compared with saline-treated SCI rats, erythropoietin-treated SCI rats showed significantly less locomotor dysfunction and faster locomotor recovery. Immunohistochemistry showed that erythropoietin-treated SCI rats had a significantly lower phospho-extracellular signal-regulated kinase (p-ERK) protein expression and a significantly higher mitogen-activated protein kinase phosphatase-1 (MKP-1) protein expression than saline-treated SCI rats. Haematoxylin–eosin staining showed progressive disruption of dorsal white matter and neuron loss after SCI; lesions were less severe and there was more neuron regeneration in the erythropoietin group than in the saline group. It is concluded that erythropoietin reduces pathological changes and SCI severity via down-regulation of p-ERK and up-regulation of MKP-1.
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Wang YG, Ji X, Pabbidi M, Samarel AM, Lipsius SL. Laminin acts via focal adhesion kinase/phosphatidylinositol-3' kinase/protein kinase B to down-regulate beta1-adrenergic receptor signalling in cat atrial myocytes. J Physiol 2008; 587:541-50. [PMID: 19064616 DOI: 10.1113/jphysiol.2008.163824] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We previously reported that short-term (2 h) plating of cat atrial myocytes on the extracellular matrix protein, laminin (LMN) decreases adenylate cyclase activity and beta(1)-adrenergic receptor (beta(1)-AR) stimulation of L-type Ca(2+) current (I(Ca,L)). The present study sought to determine whether LMN-mediated down-regulation of beta(1) signalling is due to down-regulation of adenylate cyclase and to gain insight into the signalling mechanisms responsible. beta(1)-AR stimulation was achieved by 0.01 microm isoproterenol (isoprenaline) plus 0.1 microm ICI 118551, a selective beta(2)-AR antagonist. Atrial myocytes were plated for at least 2 h on uncoated cover-slips (-LMN) or cover-slips coated with LMN (+LMN). As previously reported, beta(1)-AR stimulation of I(Ca,L) was significantly smaller in +LMN compared to -LMN atrial myocytes. In -LMN myocytes, 10 microm LY294002 (LY), a specific inhibitor of PI-(3)K, had no effect on beta(1)-AR stimulation of I(Ca,L). In +LMN myocytes, however, LY significantly increased beta(1)-AR stimulation of I(Ca,L). Western blots revealed that compared with -LMN myocytes, +LMN myocytes showed a significant increase in Akt phosphorylation at Ser-473, which was prevented by LY. In another approach, +LMN myocytes were infected (multiplicity of infection (MOI), 100; 24 h) with replication-defective adenoviruses (Adv) expressing dominant-negative inhibitors of focal adhesion kinase (FAK) (Adv-FRNK or Adv-Y397F-FAK) or Akt (Adv-dnAkt). Compared with control cells infected with Adv-beta-galactosidase, cells infected with Adv-FRNK, Adv-Y397F-FAK or Adv-dnAkt each exhibited a significantly greater beta(1)-AR stimulation of I(Ca,L). In -LMN myocytes LY had no effect on forskolin (FSK)-stimulated I(Ca,L). However, in +LMN myocytes LY significantly increased FSK-stimulated I(Ca,L). Similar results were obtained in +LMN atrial myocytes infected with Adv-FRNK. We conclude that LMN binding to beta(1)-integrin receptors acts via FAK/PI-(3)K/Akt to inhibit adenylate cyclase activity and thereby down-regulates beta(1)-AR-mediated stimulation of I(Ca,L). These findings provide new insight into the cellular mechanisms by which the extracellular matrix can modulate atrial beta-AR signalling.
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Shaw G, Gan J, Zhou Y, Zhi H, Subburaman P, Zhang R, Joachimiak A, Jin D, Ji X. Structure of a Swi2/Snf2 protein (RapA) and mechanism of RNAP recycling during transcription. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308088041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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169
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Ji X, Pal A, Kalathur R, Hu X, Gu Y, Saavedra J, Buzard G, Srinivasan A, Keefer L, Singh S. Structure-based design of anticancer prodrug PABA/NO. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308089058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Wang YG, Zima AV, Ji X, Pabbidi R, Blatter LA, Lipsius SL. Ginsenoside Re suppresses electromechanical alternans in cat and human cardiomyocytes. Am J Physiol Heart Circ Physiol 2008; 295:H851-9. [PMID: 18567703 DOI: 10.1152/ajpheart.01242.2007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ginseng botanicals are increasingly used as complementary or alternative medicines for a variety of cardiovascular diseases, yet little is known about their cellular actions in cardiac muscle. Electromechanical alternans (EMA) is a proarrhythmic cardiac abnormality that results from disturbances of intracellular Ca(2+) homeostasis. This study sought to determine whether a purified ginsenoside extract of ginseng, Re, exerts effects to suppress EMA and to gain insight into its mechanism of action. Alternans was induced by electrically pacing cardiomyocytes at room temperature. Re (> or = 10 nM) reversibly suppressed EMA recorded from cat ventricular and atrial myocytes and Langendorff-perfused cat hearts. In cat ventricular myocytes, Re reversibly suppressed intracellular Ca(2+) concentration ([Ca(2+)](i)) transient alternans. Re exerted no significant effects on baseline action potential configuration or sarcolemmal L-type Ca(2+) current (I(Ca,L)), Na(+) current, or total K(+) conductance. In human atrial myocytes, Re suppressed mechanical alternans and exerted no effect on I(Ca,L). In cat ventricular myocytes, Re increased [Ca(2+)](i) transient amplitude and decreased sarcoplasmic reticulum (SR) Ca(2+) content, resulting in an increase in fractional SR Ca(2+) release. In SR microsomes isolated from cat ventricles, Re had no effect on SR Ca(2+) uptake. Re increased the open probability of ryanodine receptors (RyRs), i.e., SR Ca(2+)-release channels, isolated from cat ventricles and incorporated into planar lipid bilayers. We concluded that ginsenoside Re suppresses EMA in cat atrial and ventricular myocytes, cat ventricular muscle, and human atrial myocytes. The effects of Re are not mediated via actions on sarcolemmal ion channels or action potential configuration. Re acts via a subcellular mechanism to enhance the opening of RyRs and thereby overcome the impaired SR Ca(2+) release underlying EMA.
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Young RM, Wang SJ, Gordan JD, Ji X, Liebhaber SA, Simon MC. Hypoxia-mediated selective mRNA translation by an internal ribosome entry site-independent mechanism. J Biol Chem 2008; 283:16309-19. [PMID: 18430730 DOI: 10.1074/jbc.m710079200] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Although it is advantageous for hypoxic cells to inhibit protein synthesis and conserve energy, it is also important to translate mRNAs critical for adaptive responses to hypoxic stress. Because internal ribosome entry sites (IRES) have been postulated to mediate this preferential synthesis, we analyzed the 5 '-untranslated regions from a panel of stress-regulated mRNAs for m(7)GTP cap-independent translation and identified putative IRES elements in encephalomyocarditis virus, vascular endothelial growth factor, hypoxia-inducible factors (HIFs) 1alpha and 2alpha, glucose transporter-like protein 1, p57(Kip2), La, BiP, and triose phosphate isomerase transcripts. However, when capped and polyadenylated dicistronic RNAs were synthesized in vitro and transfected into cells, cellular IRES-mediated translation accounted for less than 1% that of the level of cap-dependent translation. Moreover, hypoxic stress failed to activate cap-independent synthesis, indicating that it is unlikely that this is the primary mechanism for the maintenance of the translation of these mRNAs under low O(2). Furthermore, although HIF-1alpha is frequently cited as an example of an mRNA that is preferentially translated, we demonstrate that under different levels and durations of hypoxic stress, changes in newly synthesized HIF-1alpha and beta-actin protein levels mirror alterations in corresponding mRNA abundance. In addition, our data suggest that cyclin-dependent kinase inhibitor p57(Kip2) and vascular endothelial growth factor mRNAs are selectively translated by an IRES-independent mechanism under hypoxic stress.
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Zhu JW, Luo D, Li CR, Lu Y, Ji X, Zhu J, Ming YL, Shen CH. A case of penile verrucous carcinoma associated with cutaneous horn. Clin Exp Dermatol 2007; 32:213-4. [PMID: 17342801 DOI: 10.1111/j.1365-2230.2006.02289.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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173
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Chendrimada TP, Finn KJ, Ji X, Baillat D, Gregory RI, Liebhaber SA, Pasquinelli AE, Shiekhattar R. MicroRNA silencing through RISC recruitment of eIF6. Nature 2007; 447:823-8. [PMID: 17507929 DOI: 10.1038/nature05841] [Citation(s) in RCA: 343] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Accepted: 04/13/2007] [Indexed: 12/13/2022]
Abstract
MicroRNAs (miRNAs) are a class of small RNAs that act post-transcriptionally to regulate messenger RNA stability and translation. To elucidate how miRNAs mediate their repressive effects, we performed biochemical and functional assays to identify new factors in the miRNA pathway. Here we show that human RISC (RNA-induced silencing complex) associates with a multiprotein complex containing MOV10--which is the homologue of Drosophila translational repressor Armitage--and proteins of the 60S ribosome subunit. Notably, this complex contains the anti-association factor eIF6 (also called ITGB4BP or p27BBP), a ribosome inhibitory protein known to prevent productive assembly of the 80S ribosome. Depletion of eIF6 in human cells specifically abrogates miRNA-mediated regulation of target protein and mRNA levels. Similarly, depletion of eIF6 in Caenorhabditis elegans diminishes lin-4 miRNA-mediated repression of the endogenous LIN-14 and LIN-28 target protein and mRNA levels. These results uncover an evolutionarily conserved function of the ribosome anti-association factor eIF6 in miRNA-mediated post-transcriptional silencing.
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174
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Zeng Y, Song C, Ding X, Ji X, Yi L, Zhu K. Baicalin reduces the severity of experimental autoimmune encephalomyelitis. Braz J Med Biol Res 2007; 40:1003-10. [PMID: 17653455 DOI: 10.1590/s0100-879x2006005000115] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Accepted: 03/26/2007] [Indexed: 11/21/2022] Open
Abstract
Scutellaria baicalensis Georgi is one of the important medicinal herbs widely used for the treatment of various inflammatory diseases in Asia. Baicalin (BA) is a bioactive anti-inflammatory flavone found abundantly in Scutellaria baicalensis Georgi. To explore the therapeutic potential of BA, we examined the effects of systemic administration of the flavone (5 and 10 mg/kg, ip) on relapsing/remitting experimental autoimmune encephalomyelitis (EAE) induced by proteolipid protein 139-151 in SJL/J mice, an experimental model of multiple sclerosis. The mice treated with PBS or BA at day -1 and for 3 consecutive days were observed daily for clinical signs of disease up to 60 days after immunization. In the PBS-EAE group, neurological scores were: incidence (100%), mean day of onset (8.0 +/- 0.73), peak clinical score (3.0 +/- 0.4), and cumulative disease index (141.8 +/- 19.4). In the BA-EAE group (5 or 10 mg kg(-1) day(-1), respectively), incidence (95 or 90%), mean day of onset (9.0 +/- 0.80 or 9.2 +/- 0.75; P = 0.000), peak clinical score (2.2 +/- 0.3 or 2.0 +/- 0.3; P = 0.000), and cumulative disease index (75.9 +/- 10.1 or 62.9 +/- 8.4; P = 0.000) decreased, accompanied by the histopathological findings (decrease of dense mononuclear infiltration surrounding vascellum) for the spinal cord. Additionally, the in vitro effects of BA (5, 10, and 25 microM) on mononuclear cells collected from popliteal and inguinal lymph nodes of day-10 EAE mice were evaluated using an MTT reduction assay for cell proliferation, and ELISA to measure IFN-gamma and IL-4 cytokines. Compared with the control group, BA caused an increase in IL-4 (EAE-DMSO: 3.56 +/- 0.42 pg/mL vs EAE-BA (5, 10, and 25 microM): 6.03 +/- 1.1, 7.83 +/- 0.65, 10.54 +/- 1.13 pg/mL, respectively; P < 0.001); but inhibited IFN-gamma (EAE-DMSO: 485.76 +/- 25.13 pg/mL vs EAE-BA (5, 10, and 25 microM): 87.08 +/- 9.24, 36.27 +/- 5.44, 19.18 +/- 2.93 pg/mL, respectively; P < 0.001) and the proliferation of mononuclear cells (EAE-DMSO: 0.73 +/- 0.021 vs EAE-BA (5, 10, and 25 microM): 0.41 +/- 0.015, 0.31 +/- 0.018, 0.21 +/- 0.11, respectively; P < 0.001) in a concentration-dependent manner. The results suggest that BA might be effective in the treatment of multiple sclerosis.
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175
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Ji X, Kong J, Carstens RP, Liebhaber SA. The 3' untranslated region complex involved in stabilization of human alpha-globin mRNA assembles in the nucleus and serves an independent role as a splice enhancer. Mol Cell Biol 2007; 27:3290-302. [PMID: 17325043 PMCID: PMC1899960 DOI: 10.1128/mcb.02289-05] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 12/27/2005] [Accepted: 02/08/2007] [Indexed: 11/20/2022] Open
Abstract
Posttranscriptional controls, mediated primarily by RNA-protein complexes, have the potential to alter multiple steps in RNA processing and function. Human alpha-globin mRNA is bound at a C-rich motif in the 3' untranslated region (3'UTR) by the KH domain protein alpha-globin poly(C)-binding protein (alphaCP). This "alpha-complex" is essential to cytoplasmic stability of alpha-globin mRNA in erythroid cells. Here we report that the 3'UTR alpha-complex also serves an independent nuclear role as a splice enhancer. Consistent with this role, we find that alphaCP binds alpha-globin transcripts prior to splicing. Surprisingly, this binding occurs at C-rich sites within intron I as well as at the 3'UTR C-rich determinant. The intronic and 3'UTR alphaCP complexes appear to have distinct effects on splicing. While intron I complexes repress intron I excision, the 3'UTR complex enhances splicing of the full-length transcript both in vivo and in vitro. In addition to its importance to splicing, nuclear assembly of the 3'UTR alphaCP complex may serve to "prepackage" alpha-globin mRNA with its stabilizing complex prior to cytoplasmic export. Linking nuclear and cytoplasmic controls by the action of a particular RNA-binding protein, as reported here, may represent a modality of general importance in eukaryotic gene regulation.
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176
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Ji X, Lin CX, Lin LH, Qiu QB, DU Y. Evolution of viviparity in warm-climate lizards: an experimental test of the maternal manipulation hypothesis. J Evol Biol 2007; 20:1037-45. [PMID: 17465914 DOI: 10.1111/j.1420-9101.2006.01296.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The maternal manipulation hypothesis for the evolution of reptilian viviparity has been claimed to apply to any situation where gravid females are able to maintain body temperatures different from those available in external nests, but empirical data that support this hypothesis are very limited. Here, we tested this hypothesis using gravid females of a warm-climate lizard, Mabuya multifasciata, by subjecting them to five thermal regimes for the whole gestation period. We found gravid females selected lower body temperatures and thermoregulated more precisely than did nongravid females. Offspring produced in different treatments differed in head size, limb length and sprint speed, but not in overall body size or mass. Variation in morphological traits of offspring was induced primarily by extreme temperatures. Sprint speed of offspring was more likely affected by the mean but not by the variance of gestation temperatures. Gravid females maintained more stable body temperatures than did nongravid females not because these temperatures resulted in the optimization of offspring phenotypes but because the range of temperatures optimal for embryonic development was relatively narrow. Our data conform to the main predictions from the maternal manipulation hypothesis that females should adjust thermoregulation during pregnancy to provide optimal thermal conditions for developing embryos and that phenotypic traits forged by maternal thermoregulation should enhance offspring fitness.
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177
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Dedkova EN, Wang YG, Ji X, Blatter LA, Samarel AM, Lipsius SL. Signalling mechanisms in contraction-mediated stimulation of intracellular NO production in cat ventricular myocytes. J Physiol 2007; 580:327-45. [PMID: 17234690 PMCID: PMC2075434 DOI: 10.1113/jphysiol.2006.126805] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In this study we sought to determine whether contractile activity has a role as a signalling mechanism in the activation of intracellular nitric oxide (NO(i)) production induced by electrical stimulation of cat ventricular myocytes. Field stimulation (FS) of single ventricular myocytes elicited frequency-dependent increases in NO(i) that were blocked by the calmodulin (CaM) inhibitor 10 microM W-7 and partially inhibited by the phosphatidylinositol 3'-kinase (PI-(3)K) inhibitor 10 microMm LY294002. Increasing extracellular [Ca(2+)] caused a concentration-dependent increase in FS-induced NO(i) that was partially inhibited by LY294002. The negative inotropic agents BDM (5 mm) or blebbistatin (10 microM) decreased cell shortening and NO(i) production without concomitant changes in L-type Ca(2+) current (I(Ca,L)) or [Ca(2+)](i) transients. The positive inotropic agents EMD 57033 or CGP 48506 (1 microM) increased cell shortening and NO(i) production without concomitant changes in I(Ca,L) or [Ca(2+)](i) transients. FS-induced NO(i) production was decreased in myocytes infected (100 multiplicity of viral infection (MOI); 24 h) with a replication-deficient adenovirus expressing a dominant-negative mutant of protein kinase B (Akt) compared with cells infected with a control adenovirus expressing beta-galactosidase. FS-induced NO(i) was partially inhibited by either endothelial (eNOS) or neuronal nitric oxide synthase (nNOS) inhibitors and completely blocked by simultaneous exposure to both. FS-induced [Ca(2+)](i) transients were increased by the nNOS inhibitor nNOS-I (0.24 microM), decreased by the eNOS inhibitor L-NIO (1 microM) and unchanged by exposure to both inhibitors. We conclude that in cat ventricular myocytes, FS-induced NO(i) production requires both Ca(2+)-dependent CaM signalling and Ca(2+)-independent PI-(3)K-Akt signalling activated by contractile activity. FS activates NO(i) production from both eNOS and nNOS, and each source of NO(i) exerts opposing effects on [Ca(2+)](i) transient amplitude. These findings are important for understanding the regulation of NO(i) signalling in the normal and mechanically failing heart.
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Aoyama N, Takahashi N, Saito S, Maeno N, Ishihara R, Ji X, Miura H, Ikeda M, Suzuki T, Kitajima T, Yamanouchi Y, Kinoshita Y, Yoshida K, Iwata N, Inada T, Ozaki N. Association study between kynurenine 3-monooxygenase gene and schizophrenia in the Japanese population. GENES BRAIN AND BEHAVIOR 2006; 5:364-8. [PMID: 16716206 DOI: 10.1111/j.1601-183x.2006.00231.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Several lines of evidence suggest that metabolic changes in the kynurenic acid (KYNA) pathway are related to the etiology of schizophrenia. The inhibitor of kynurenine 3-monooxygenase (KMO) is known to increase KYNA levels, and the KMO gene is located in the chromosome region associated with schizophrenia, 1q42-q44. Single-marker and haplotype analyses for 6-tag single nucleotide polymorphisms (SNPs) of KMO were performed (cases = 465, controls = 440). Significant association of rs2275163 with schizophrenia was observed by single-marker comparisons (P = 0.032) and haplotype analysis including this SNP (P = 0.0049). Significant association of rs2275163 and haplotype was not replicated using a second, independent set of samples (cases = 480, controls = 448) (P = 0.706 and P = 0.689, respectively). These results suggest that the KMO is unlikely to be related to the development of schizophrenia in Japanese.
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179
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Naruishi K, Timme TL, Kusaka N, Fujita T, Yang G, Goltsov A, Satoh T, Ji X, Tian W, Abdelfattah E, Men T, Watanabe M, Tabata K, Thompson TC. Adenoviral vector-mediated RTVP-1 gene-modified tumor cell-based vaccine suppresses the development of experimental prostate cancer. Cancer Gene Ther 2006; 13:658-63. [PMID: 16485011 DOI: 10.1038/sj.cgt.7700919] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We previously identified a novel p53 target gene, RTVP-1, that possesses unique cytotoxic and immunostimulatory activities which make it potentially useful for cancer gene therapy. To test the therapeutic potential of RTVP-1 in a gene-modified tumor cell-based vaccine model, we used an adenoviral vector capable of efficient transduction and expression of RTVP-1 (AdRTVP-1), together with a highly metastatic mouse prostate cancer cell line (178-2 BMA). A vaccine was prepared with 178-2 BMA cells transduced with AdRTVP-1 or a control adenoviral vector expressing beta-galactosidase (Adbetagal). After irradiation of the cells, syngeneic 129/Sv mice were vaccinated three times at weekly intervals. After 3 weeks, they were challenged with orthotopic 178-2 BMA cells. After 21 days, fewer than 60% of the RTVP-1-cell-vaccinated mice developed tumors compared to 100% of the control mice. The RTVP-1-cell vaccine significantly reduced primary tumor wet weight compared with control Adbetagal-cell vaccine (P<0.0001 at 7 and 14 days). Experimental metastasis to lung was also significantly reduced (P=0.0377), and survival significantly increased (P=0.0002). In addition, significantly increased NK and CTL activities were demonstrated in the AdRTVP-1-cell-vaccinated mice. These findings indicate that RTVP-1 gene-modified cell-based vaccines may be useful in the prevention of recurrent prostate cancer.
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180
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Wang YG, Dedkova EN, Ji X, Blatter LA, Lipsius SL. Phenylephrine acts via IP3-dependent intracellular NO release to stimulate L-type Ca2+ current in cat atrial myocytes. J Physiol 2005; 567:143-57. [PMID: 15946966 PMCID: PMC1474159 DOI: 10.1113/jphysiol.2005.090035] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
This study determined the effects of alpha1-adrenergic receptor (alpha1-AR) stimulation by phenylephrine (PE) on L-type Ca2+ current (I(Ca,L)) in cat atrial myocytes. PE (10 microm) reversibly increased I(Ca,L) (51.3%; n = 40) and shifted peak I(Ca,L) activation voltage by -10 mV. PE-induced stimulation of I(Ca,L) was blocked by each of 1 microm prazocin, 10 microm L-NIO, 10 microm W-7, 10 microm ODQ, 2 microm H-89 or 10 microm LY294002, and was unaffected by 10 microm chelerythrine or incubating cells in pertussis toxin (PTX). PE-induced stimulation of I(Ca,L) also was inhibited by each of 10 microm ryanodine or 5 microm thapsigargin, by blocking IP3 receptors with 2 microm 2-APB or 10 microm xestospongin C or by intracellular dialysis of heparin. In field-stimulated cells, PE increased intracellular NO (NOi) production. PE-induced NOi release was inhibited by each of 1 microm prazocin, 10 microm L-NIO, 10 microm W-7, 10 microm LY294002, 2 microm H-89, 10 microm ryanodine, 5 microm thapsigargin, 2 microm 2-APB or 10 microm xestospongin C, and unchanged by PTX. PE (10 microm) increased phosphorylation of Akt, which was inhibited by LY294002. Confocal microscopy showed that PE stimulated NOi release from subsarcolemmal sites and this was prevented by 2 mm methyl-beta-cyclodextrin, an agent that disrupts caveolae formation. PE also increased local, subsarcolemmal SR Ca2+ release via IP3-dependent signalling. Electron micrographs of atrial myocytes show peripheral SR cisternae in close proximity to clusters of caveolae. We conclude that in cat atrial myocytes PE acts via alpha1-ARs coupled to PTX-insensitive G-protein to release NOi, which in turn stimulates I(Ca,L). PE-induced NOi release requires stimulation of both PI-3K/Akt and IP3-dependent Ca2+ signalling. NO stimulates I(Ca,L) via cGMP-mediated cAMP-dependent PKA signalling. IP3-dependent Ca2+ signalling may enhance local SR Ca2+ release required to activate Ca2+-dependent eNOS/NOi production from subsarcolemmal caveolae sites.
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181
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Ji X, Zhang Q, Liu Y. Presence of plastid and absence of mitochondrial DNA in male reproductive cells as evidence for cytoplasmic inheritance in Turnera ulmifolia and Zantedeschia aethiopica. PROTOPLASMA 2004; 224:211-216. [PMID: 15614482 DOI: 10.1007/s00709-004-0065-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2004] [Accepted: 03/23/2004] [Indexed: 05/24/2023]
Abstract
Epifluorescence microscopy of mature pollen grains of Turnera ulmifolia and Zantedeschia aethiopica stained with 4',6-diamidino-2-phenylindole demonstrated the presence of fluorescent cytoplasmic DNA aggregates in the male reproductive cells of both species. Double staining of the cells with 4',6-diamidino-2-phenylindole and 3,3'-dihexyloxacarbocyanine iodide in Technovit resin sections showed that the mitochondria of these cells did not correspond to the fluorescent cytoplasmic DNA aggregates. Electron microscopy studies revealed both plastids and mitochondria in the cells of these species. In addition, immunoelectron microscopy using an anti-DNA monoclonal antibody showed clear labeling of plastids but not mitochondria. These data provide cytological evidence for biparental plastid inheritance and maternal mitochondrial inheritance in these species.
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182
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Weinberg RS, Ji X, Sutton M, Perrine S, Galperin Y, Li Q, Liebhaber SA, Stamatoyannopoulos G, Atweh GF. Butyrate increases the efficiency of translation of gamma-globin mRNA. Blood 2004; 105:1807-9. [PMID: 15479724 PMCID: PMC2826269 DOI: 10.1182/blood-2004-02-0454] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fetal hemoglobin (Hb F) levels increase in most patients with sickle cell disease following intermittent butyrate therapy. Although the full effects of butyrate on Hb F levels usually require multiple treatment cycles, in some patients a peak level is achieved after a few days of butyrate therapy. Our investigation of the mechanism(s) responsible for this rapid induction of Hb F by butyrate showed that reticulocyte gamma-globin chain synthesis markedly increased within 24 hours of butyrate exposure, without concomitant changes in reticulocyte gamma-globin mRNA levels. This suggests that butyrate might induce Hb F by increasing the efficiency of translation of gamma-globin mRNA. This hypothesis was confirmed by ribosome loading studies that demonstrated enrichment of the polysomal fraction of reticulocytes with gamma-globin mRNA following butyrate exposure. Thus, the induction of Hb F by butyrate may be mediated by translational effects in addition to its well-known effects on transcription of the gamma-globin genes.
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183
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Fujita T, Teh B, Naruishi K, Kusaka N, Satoh T, Zhu X, Ji X, Yang G, Timme T, Vlachaki M, Butler E, Thompson T. Combinatorial effect of adenoviral vector mediated interleukin 12 gene therapy with radiotherapy in a preclinical mouse model of metastatic prostate cancer. Int J Radiat Oncol Biol Phys 2004. [DOI: 10.1016/j.ijrobp.2004.07.379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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184
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Krauss J, Arndt MAE, Zhu Z, Newton DL, Vu BK, Choudhry V, Darbha R, Ji X, Courtenay-Luck NS, Deonarain MP, Richards J, Rybak SM. Impact of antibody framework residue VH-71 on the stability of a humanised anti-MUC1 scFv and derived immunoenzyme. Br J Cancer 2004; 90:1863-70. [PMID: 15150594 PMCID: PMC2409732 DOI: 10.1038/sj.bjc.6601759] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Anti-MUC1 single-chain Fv (scFv) fragments generated from the humanised antibody huHMFG1 had adequate antigen-binding properties but very poor stability irrespective of the applied linker or domain orientation. Mutagenesis of heavy-chain framework residue VH-71, previously described as a key residue for maintaining the CDR-H2 main-chain conformation and thus important for antigen binding, markedly stabilised the scFv while having only a minor effect on the binding affinity of the molecule. Because of its improved stability, the engineered fragment exhibited immunoreactivity with tumour cells even after 7 days of incubation in human serum at 37°C. It also showed, in contrast to the wild-type scFv, a concentration-dependent binding to the target antigen when displayed on phage. When fusing the scFv to the recombinant ribonuclease rapLRI, only the fusion protein generated with the stable mutant scFv was able to kill MUC1+ tumour cells with an IC50 of 80 nM. We expect this novel immunoenzyme to become a promising tool for the treatment of MUC1+ malignancies.
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185
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Inácio A, Silva AL, Pinto J, Ji X, Morgado A, Almeida F, Faustino P, Lavinha J, Liebhaber SA, Romão L. Nonsense mutations in close proximity to the initiation codon fail to trigger full nonsense-mediated mRNA decay. J Biol Chem 2004; 279:32170-80. [PMID: 15161914 DOI: 10.1074/jbc.m405024200] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a surveillance mechanism that degrades mRNAs containing premature translation termination codons. In mammalian cells, a termination codon is ordinarily recognized as "premature" if it is located greater than 50-54 nucleotides 5' to the final exon-exon junction. We have described a set of naturally occurring human beta-globin gene mutations that apparently contradict this rule. The corresponding beta-thalassemia genes contain nonsense mutations within exon 1, and yet their encoded mRNAs accumulate to levels approaching wild-type beta-globin (beta(WT)) mRNA. In the present report we demonstrate that the stabilities of these mRNAs with nonsense mutations in exon 1 are intermediate between beta(WT) mRNA and beta-globin mRNA carrying a prototype NMD-sensitive mutation in exon 2 (codon 39 nonsense; beta 39). Functional analyses of these mRNAs with 5'-proximal nonsense mutations demonstrate that their relative resistance to NMD does not reflect abnormal RNA splicing or translation re-initiation and is independent of promoter identity and erythroid specificity. Instead, the proximity of the nonsense codon to the translation initiation AUG constitutes a major determinant of NMD. Positioning a termination mutation at the 5' terminus of the coding region blunts mRNA destabilization, and this effect is dominant to the "50-54 nt boundary rule." These observations impact on current models of NMD.
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186
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Wan J, Martinvalet D, Ji X, Lois C, Kaech SM, Von Andrian UH, Lieberman J, Ahmed R, Manjunath N. The Bcl-2 family pro-apoptotic molecule, BNIP3 regulates activation-induced cell death of effector cytotoxic T lymphocytes. Immunology 2003; 110:10-7. [PMID: 12941136 PMCID: PMC1783016 DOI: 10.1046/j.1365-2567.2003.01710.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BNIP3 is a recently described pro-apoptotic member of the Bcl-2 family and in BNIP3 cDNA-transfected cell lines, cell death occurs via a caspase-independent pathway with opening of the mitochondrial permeability transition (PT) pore and rapid loss of mitochondrial transmembrane potential (Delta psi m). However, its expression or function in physiologic cell types is not known. Our results using the T-cell receptor transgenic mice P14, specific for lymphocyte choreomeningitis virus (LCMV) glycoprotein, show that in contrast to the other Bcl-2 family pro-apoptotic molecules, BNIP3 is transcriptionally highly up-regulated in effector cytotoxic T lymphocytes (CTL). Because CTL have a propensity to undergo activation-induced cell death (AICD) upon restimulation, we tested for other features associated with BNIP3-induced cell death. AICD of CTL was caspase-independent as determined by measuring caspase activation during target cell killing as well as by lack of inhibition with caspase inhibitors. Moreover, similar to BNIP3-induced cell death, CTL apoptosis was associated with increased production of reactive oxygen species and decreased Delta psi m. Finally, retroviral transduction of BNIP3 antisense RNA diminished AICD in effector CTL. These results suggest that BNIP3 may play an important role in T-cell homeostasis by regulating effector CTL numbers.
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187
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Ji X, Kong J, Liebhaber SA. In vivo association of the stability control protein alphaCP with actively translating mRNAs. Mol Cell Biol 2003; 23:899-907. [PMID: 12529395 PMCID: PMC140719 DOI: 10.1128/mcb.23.3.899-907.2003] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Posttranscriptional controls play a major role in eucaryotic gene expression. These controls are mediated by sequence-specific interactions of cis-acting determinants in target mRNAs with one or more protein factors. The positioning of a subset of these mRNA-protein (RNP) complexes within the 3' untranslated region (3' UTR) may allow them to remain associated with the mRNA during active translation. Robust expression of human alpha-globin mRNA during erythroid differentiation has been linked to formation of a binary complex between a KH-domain protein, alphaCP, and a 3' UTR C-rich motif. Detection of this "alpha-complex" has been limited to in vitro studies, and the functional state of the alpha-globin mRNA targeted by alphaCP has not been defined. In the present study we demonstrate that a significant fraction of alphaCP is associated with polysomal mRNA. Targeted analysis of the polysomal RNP complexes revealed that alphaCP is specifically bound to actively translating alpha-globin mRNA. The bound alphaCP is restricted to the poly(C)-rich 3' UTR motif and is dislodged when ribosomes are allowed to enter this region. These data validate the general importance of the 3' UTR as a sheltered site for RNP complexes and support a specific model in which the stabilizing function of alphaCP is mediated on actively translating target mRNAs.
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188
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Kong J, Ji X, Liebhaber SA. The KH-domain protein alpha CP has a direct role in mRNA stabilization independent of its cognate binding site. Mol Cell Biol 2003; 23:1125-34. [PMID: 12556474 PMCID: PMC141145 DOI: 10.1128/mcb.23.4.1125-1134.2003] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2002] [Revised: 10/01/2002] [Accepted: 11/13/2002] [Indexed: 11/20/2022] Open
Abstract
Previous studies suggest that high-level stability of a subset of mammalian mRNAs is linked to a C-rich motif in the 3' untranslated region (3'UTR). High-level expression of human alpha-globin mRNA (h alpha-globin mRNA) in erythroid cells has been specifically attributed to formation of an RNA-protein complex comprised of a 3'UTR C-rich motif and an associated 39-kDa poly(C) binding protein, alpha CP. Documentation of this RNA-protein alpha-complex has been limited to in vitro binding studies, and its impact has been monitored by alterations in steady-state mRNA. Here we demonstrate that alpha CP is stably bound to h alpha-globin mRNA in vivo, that alpha-complex assembly on the h alpha-globin mRNA is restricted to the 3'UTR C-rich motif, and that alpha-complex assembly extends the physical half-life of h alpha-globin mRNA selectively in erythroid cells. Significantly, these studies also reveal that an artificially tethered alpha CP has the same mRNA-stabilizing activity as the native alpha-complex. These data demonstrate a unique contribution of the alpha-complex to h alpha-globin mRNA stability and support a model in which the sole function of the C-rich motif is to selectively tether alpha CP to a subset of mRNAs. Once bound, alpha CP appears to be fully sufficient to trigger downstream events in the stabilization pathway.
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189
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Abstract
6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) belongs to a class of catalytic enzymes involved in phosphoryl transfer and is a new target for the development of novel antimicrobial agents. In the present study, the fundamental consideration is to view the overall structure of HPPK as a network of interacting residues and to extract the most cooperative collective motions that define its global dynamics. A coarse-grained model, harmonically constrained according to HPPK's crystal structure is used. Four crystal structures of HPPK (one apo and three holo forms with different nucleotide and pterin analogs) are studied with the goal of providing insights about the function-dynamic correlation and ligand induced conformational changes. The dynamic differences are examined between HPPK's apo- and holo-forms, because they are involved in the catalytic reaction steps. Our results indicate that the palm-like structure of HPPK is nearly rigid, whereas the two flexible loops: L2 (residues 43-53) and L3 (residues 82-92) exhibit the most concerted motions for ligand recognition and presumably, catalysis. These two flexible loops are involved in the recognition of HPPKs nucleotide and pterin ligands, whereas the rigid palm region is associated with binding of these cognate ligands. Six domains of collective motions are identified, comprised of structurally close but not necessarily sequential residues. Two of these domains correspond to the flexible loops (L2 and L3), whereas the remaining domains correspond to the rigid part of the molecule.
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190
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Papadopoulou MV, Ji M, Ji X, Bloomer WD. Therapeutic advantage from combining 5-fluorouracil with the hypoxia-selective cytotoxin NLCQ-1 in vivo; comparison with tirapazamine. Cancer Chemother Pharmacol 2002; 50:291-8. [PMID: 12357303 DOI: 10.1007/s00280-002-0491-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2002] [Accepted: 06/07/2002] [Indexed: 11/26/2022]
Abstract
PURPOSE The antitumor effect and bone marrow toxicity of 5-fluorouracil (5FU) in combination with the hypoxia-selective cytotoxins NLCQ-1 or tirapazamine (TPZ) were investigated in vivo. METHODS Using appropriate intraperitoneal administration schedules for optimal synergistic interactions, the antitumor effect and the bone marrow toxicity of combinations of NLCQ-1 or TPZ and 5FU were determined in EMT6/BALB/c and SCCVII/C3H models in terms of dose modification factors (DMF) using the in vivo-in vitro clonogenic assay as endpoint. Bone marrow toxicity studies were performed in parallel using a modified CFU-GM assay. The antitumor efficacies of each combination treatment under optimal administration conditions were evaluated in the SCCVII/C3H model using also the tumor regrowth assay as endpoint. RESULTS A schedule-dependent and tumor-specific synergistic interaction was observed for NLCQ-1 plus 5FU and DMFs of 2.0-2.3 and 1.0 were obtained for the antitumor effect and bone marrow toxicity, respectively, in both tumor models. The antitumor effect of 5FU was slightly potentiated (DMF 1.2) by TPZ in the EMT6/BALB/c model but not in the SCCVII/C3H model when the in vivo-in vitro assay was used as the endpoint. Significant additional tumor regrowth delays (about 11 and 6 days for NLCQ-1 and TPZ, respectively) were observed, compared to the effect of 5FU alone, when an equitoxic dose of NLCQ-1 (10 mg/kg) or TPZ (23 mg/kg) was administered 1 h before 5FU (50 mg/kg) twice a day at 4-h intervals on days 0 and 9. CONCLUSIONS These results corroborate the therapeutic advantage of combining hypoxia-selective cytotoxins such as NLCQ-1 and TPZ with chemotherapy.
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191
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Ji X, Blaszczyk J, Tropea JE, Bubunenko M, Routzahn KM, Waugh DS, Court DL. Compound active center of ribonuclease III: molecular basis for double-stranded RNA cleavage. Acta Crystallogr A 2002. [DOI: 10.1107/s0108767302097222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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192
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Fang Z, Liu YW, Shi YK, Yu XB, Huang WQ, Ji X. The humoral immune responses elicited in mice by inoculations with a recombinant protein or DNA based on the circumsporozoite-protein gene of Plasmodium falciparum. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2002; 96:463-8. [PMID: 12194706 DOI: 10.1179/000349802125001258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The humoral responses elicited in mice by inoculation, in various doses and by several routes, with plasmid DNA containing the gene coding for the circumsporozoite protein (CSP) of Plasmodium falciparum FCC1/HN were compared with those evoked by inoculation with a recombinant expressed protein based on the CSP. With the DNA vaccine, intramuscular inoculations appeared the most effective, followed by intravenous and then subcutaneous injections, the responses in each case being dose-dependent. In both standard ELISA and dot-ELISA, sera from the mice immunized with the DNA were found to have much lower titres of antimalarial antibodies than the corresponding sera from mice immunized with the recombinant protein. Although both 'vaccines' elicited humoral immune responses in BALB/c mice, that based on plasmid DNA took much longer than the recombinant protein to induce high-titre antibody responses.
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193
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Ji X, Liang X. [Synthesis and biological activity of 2,3-benzopyrone analogs]. YAO XUE XUE BAO = ACTA PHARMACEUTICA SINICA 2002; 33:72-4. [PMID: 11938941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Several 2, 3-benzopyrone analogs were synthesized for evaluating their K(+)-channel and anticancer activities. The Friedel-Crafts reaction was taken place with some replacement phenyl acetic acid or its methyl ester and vanillin as reactants in the condition of Ac2O/ZnCl2. All products were confirmed by means of MS and 1H, 13CNMR spectra. Compounds 2 and 3 showed obvious activities on the K(+)-channel and anticancer screening, while the activity of compound 5 was weak. Compound 4 was not yet tested. The primary result indicate that the potential activity of such compounds deserves further study.
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194
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Yan H, Blaszczyk J, Xiao B, Shi G, Ji X. Structure and dynamics of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase. J Mol Graph Model 2002; 19:70-7. [PMID: 11381532 DOI: 10.1016/s1093-3263(00)00135-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Folates are essential for life. Unlike mammals, most microorganisms must synthesize folates de novo. 6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) catalyzes pyrophosphoryl transfer from ATP to 6-hydroxymethyl-7,8-dihydropterin (HP), the first reaction in folate pathway, and therefore, is an ideal target for developing novel antimicrobial agents. Because of its small size and high thermal stability, E. coli HPPK is also an excellent model enzyme for studying the mechanisms of enzymatic pyrophosphoryl transfer. We have determined the crystal structures of HPPK in the unligated form and in complex with HP, two Mg2+ ions, and AMPCPP (an ATP analog that inhibits the enzymatic reaction). Comparison of the two crystal structures reveals dramatic conformational changes of three flexible loops and many side chains and possible roles of the active site residues.
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195
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Gu Y, Reshetnikova L, Li Y, Yan H, Singh SV, Ji X. Crystallization and preliminary X-ray diffraction analysis of shikimate kinase from Mycobacterium tuberculosis in complex with MgADP. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2001; 57:1870-1. [PMID: 11717501 DOI: 10.1107/s0907444901014032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2001] [Accepted: 08/24/2001] [Indexed: 11/10/2022]
Abstract
Shikimate kinase (SK) from Mycobacterium tuberculosis (Mt) was overexpressed in Escherichia coli, purified and cocrystallized with MgADP in hanging drops using the vapor-diffusion procedure with PEG 4000 and 2-propanol as precipitants at pH 7.5. The crystal of MtSK-MgADP, which diffracted to 2.2 A resolution, belonged to space group P3(2)21 or P3(1)21, with unit-cell parameters a = b = 64.01, c = 92.41 A. There was one MtSK molecule in the asymmetric unit. Molecular-replacement trials with the crystal structure of SK from Erwinia chrysanthemi (PDB code 1shk) and adenylate kinase (PDB code 1ake) as search models were not successful. Heavy-atom derivative screening is in progress.
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196
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Blaszczyk J, Tropea JE, Bubunenko M, Routzahn KM, Waugh DS, Court DL, Ji X. Crystallographic and modeling studies of RNase III suggest a mechanism for double-stranded RNA cleavage. Structure 2001; 9:1225-36. [PMID: 11738048 DOI: 10.1016/s0969-2126(01)00685-2] [Citation(s) in RCA: 182] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Aquifex aeolicus Ribonuclease III (Aa-RNase III) belongs to the family of Mg(2+)-dependent endonucleases that show specificity for double-stranded RNA (dsRNA). RNase III is conserved in all known bacteria and eukaryotes and has 1-2 copies of a 9-residue consensus sequence, known as the RNase III signature motif. The bacterial RNase III proteins are the simplest, consisting of two domains: an N-terminal endonuclease domain, followed by a double-stranded RNA binding domain (dsRBD). The three-dimensional structure of the dsRBD in Escherichia coli RNase III has been elucidated; no structural information is available for the endonuclease domain of any RNase III. RESULTS We present the crystal structures of the Aa-RNase III endonuclease domain in its ligand-free form and in complex with Mn(2+). The structures reveal a novel protein fold and suggest a mechanism for dsRNA cleavage. On the basis of structural, genetic, and biological data, we have constructed a hypothetical model of Aa-RNase III in complex with dsRNA and Mg(2+) ion, which provides the first glimpse of RNase III in action. CONCLUSIONS The functional Aa-RNase III dimer is formed via mainly hydrophobic interactions, including a "ball-and-socket" junction that ensures accurate alignment of the two monomers. The fold of the polypeptide chain and its dimerization create a valley with two compound active centers at each end of the valley. The valley can accommodate a dsRNA substrate. Mn(2+) binding has significant impact on crystal packing, intermolecular interactions, thermal stability, and the formation of two RNA-cutting sites within each compound active center.
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197
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Jia X, Ji X, Yang H, Ebertz S, McGann L. [The role of cell junction in hypothermic impairment of tissue]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 2001; 39:954-7. [PMID: 16201182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
OBJECTIVE To investigate the role of cell junction in the hypothermal impairment of tissue without any cryoprotectant. METHODS Epithelial MDCK cell line which is able to form well-defined cell junctions after confluency, and fibroblast V79 cell line which is unable to be used for graded freezing experiments, either in suspension, single tough attached to flasks or as monolayers on flasks. Then the viability was assessed by WST-1 and MT, respectively. RESULTS The results of viability of the two types of cells assessed by WST-1 were well-fitted with that of MTT. The recovery of the two types of cells in suspension was higher than that of single tough group and monolayer group. The single tough group of MDCK had a higher recovery than did the monolayer group. At the same time, such tendency was not observed on V79 cells. As compared with V79 monolayers, lower recovery was found on MDCK monolayers. CONCLUSIONS The junction between cells and the adhesion between cell and matrix have important roles in the hypothermic impairment of tissue. Their existence affect the recovery of cells under hypothermia. The cytoskeleton system may contribute to the impairment caused by junctions.
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Wang S, Ji X, Xiao L, Zhao X, Geng J, Liu J, Cao L. [Treatment of nuclein 32P colloid perfusion with chronic suppurative maxillary sinusitis]. LIN CHUANG ER BI YAN HOU KE ZA ZHI = JOURNAL OF CLINICAL OTORHINOLARYNGOLOGY 2001; 15:494-5. [PMID: 12541827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
OBJECTIVE To determine the effect of nuclein 32P colloid in treatment of chronic maxillary sinusitis (CMS). METHOD 22 patients (31 sides) with CMS after washing of sinucavity were perfused with nuclein 32P in sinucavity. 20 patients (31 sides) with routine conservative treatment were served as a control group. Two groups were followed up for one year. RESULT In nuclein group, 27 sides were cured, 4 sides were recurred and the rate of cure was 87%. In routine group, 19 sides were cured, 12 sides were recurred and the rate of cure is 61%. There is significant difference between the two groups (P < 0.01). The treatment active of nuclein group is better than that of routine group. CONCLUSION Nuclein 32P colloid with the function of ionizing radiation can increase the pathogenic tissue immunocompetence and metabolic course, obstruct the microvascular and promote the absorption of inflammatory exudation and edema subsidence. It can also make the proliferous tissue atrophy thence accelerate the rate of cure of CMS.
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Xiao B, Shi G, Gao J, Blaszczyk J, Liu Q, Ji X, Yan H. Unusual conformational changes in 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase as revealed by X-ray crystallography and NMR. J Biol Chem 2001; 276:40274-81. [PMID: 11546767 DOI: 10.1074/jbc.m103837200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The crystal structure of Escherichia coli 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) in complex with MgADP has been determined at 1.5-A resolution with a crystallographic R factor of 0.191. The solution structure of HPPK in complex with Mg(2+) and beta,gamma-methyleneadenosine 5'-triphosphate (MgAMPPCP) has been determined using a simulated annealing protocol with 3,523 experimental NMR restraints. The root mean square deviation of the ensemble of 20 refined conformers that represent the solution structure from the mean coordinate set derived from them is 0.74 +/- 0.26 A for all backbone atoms and 0.49 +/- 0.22 A when residues Pro(14), Pro(44)-Gln(50), and Arg(84)-Pro(91) are excluded. Binding of MgADP causes significant changes in the conformation and dynamical property of three loops of HPPK that are involved in catalysis. A dramatic, unusual conformational change is that loop 3 moves away from the active center significantly with some residues moving by >17 A. The binding of MgADP also stabilizes loop 1 and loop 3 but makes loop 2 more mobile. Very similar conformational and dynamical changes are observed in the NMR solution structure of HPPK.MgAMPPCP. The conformational and dynamical changes may play important roles in both substrate binding and product release in the catalytic cycle.
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200
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Chen JW, Ji X. Constructing parton convolution in effective field theory. PHYSICAL REVIEW LETTERS 2001; 87:152002. [PMID: 11580693 DOI: 10.1103/physrevlett.87.152002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2001] [Indexed: 05/23/2023]
Abstract
Parton convolution models have been used extensively in describing the sea quarks in the nucleon and explaining quark distributions in nuclei (the EMC effect). From the effective field theory point of view, we construct the parton convolution formalism which has been the underlying conception of all convolution models. We explain the significance of scheme and scale dependence of the auxiliary quantities such as the pion distributions in a nucleon. As an application, we calculate the complete leading nonanalytic chiral contribution to the isovector component of the nucleon sea.
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