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101.
Shulzhenko N Morgun A Hsiao W Battle M Yao M Gavrilova O Orandle M Mayer L Macpherson AJ McCoy KD Fraser-Liggett C Matzinger P 《Nature medicine》2011,17(12):1585-1593
Using a systems biology approach, we discovered and dissected a three-way interaction between the immune system, the intestinal epithelium and the microbiota. We found that, in the absence of B cells, or of IgA, and in the presence of the microbiota, the intestinal epithelium launches its own protective mechanisms, upregulating interferon-inducible immune response pathways and simultaneously repressing Gata4-related metabolic functions. This shift in intestinal function leads to lipid malabsorption and decreased deposition of body fat. Network analysis revealed the presence of two interconnected epithelial-cell gene networks, one governing lipid metabolism and another regulating immunity, that were inversely expressed. Gene expression patterns in gut biopsies from individuals with common variable immunodeficiency or with HIV infection and intestinal malabsorption were very similar to those of the B cell-deficient mice, providing a possible explanation for a longstanding enigmatic association between immunodeficiency and defective lipid absorption in humans. 相似文献
102.
Ksepka DT Benton MJ Carrano MT Gandolfo MA Head JJ Hermsen EJ Joyce WG Lamm KS Patané JS Phillips MJ Polly PD Van Tuinen M Ware JL Warnock RC Parham JF 《Biology letters》2011,7(6):801-803
Divergence dating studies, which combine temporal data from the fossil record with branch length data from molecular phylogenetic trees, represent a rapidly expanding approach to understanding the history of life. National Evolutionary Synthesis Center hosted the first Fossil Calibrations Working Group (3-6 March, 2011, Durham, NC, USA), bringing together palaeontologists, molecular evolutionists and bioinformatics experts to present perspectives from disciplines that generate, model and use fossil calibration data. Presentations and discussions focused on channels for interdisciplinary collaboration, best practices for justifying, reporting and using fossil calibrations and roadblocks to synthesis of palaeontological and molecular data. Bioinformatics solutions were proposed, with the primary objective being a new database for vetted fossil calibrations with linkages to existing resources, targeted for a 2012 launch. 相似文献
103.
This study sought to define the role of memory lymphocytes in the protection from homologous influenza A virus re-challenge in rhesus macaques. Depleting monoclonal antibodies (mAb) were administered to the animals prior to their second experimental inoculation with a human seasonal influenza A virus strain. Treatment with either anti-CD8α or anti-CD20 mAbs prior to re-challenge had minimal effect on influenza A virus replication. Thus, in non-human primates with pre-existing anti-influenza A antibodies, memory B cells and CD8α+ T cells do not contribute to the control of virus replication after re-challenge with a homologous strain of influenza A virus. 相似文献
104.
Polly J Phillips-Mason Sonya EL Craig Susann M Brady-Kalnay 《Cell Adhesion & Migration》2011,5(4):298-305
Dissolution of cell-cell adhesive contacts and increased cell-extracellular matrix adhesion are hallmarks of the migratory and invasive phenotype of cancer cells. These changes are facilitated by growth factor binding to receptor protein tyrosine kinases (RTKs). In normal cells, cell-cell adhesion molecules (CAMs), including some receptor protein tyrosine phosphatases (RPTPs), antagonize RTK signaling by promoting adhesion over migration. In cancer, RTK signaling is constitutive due to mutated or amplified RTKs, which leads to growth factor independence or autonomy. An alternative route for a tumor cell to achieve autonomy is to inactivate cell-cell CAMs such as RPTPs. RPTPs directly mediate cell adhesion and regulate both cadherin-dependent adhesion and signaling. In addition, RPTPs antagonize RTK signaling by dephosphorylating molecules activated following ligand binding. Both RPTPs and cadherins are downregulated in tumor cells by cleavage at the cell surface. This results in shedding of the extracellular, adhesive segment and displacement of the intracellular segment, altering its subcellular localization and access to substrates or binding partners. In this commentary we discuss the signals that are altered following RPTP and cadherin cleavage to promote cell migration. Tumor cells both step on the gas (RTKs) and disconnect the brakes (RPTPs and cadherins) during their invasive and metastatic journey.Key words: receptor protein tyrosine kinase, receptor-like protein tyrosine phosphatase, cadherins, cell adhesion, signal transduction, phospholipase C gamma, protein kinase C, catenins, IQGAP1 protein, regulated intramembrane proteolysis 相似文献
105.
106.
Vincent C. H. Chung Polly H. X. Ma David S. C. Hui Wilson W. S. Tam Jin Ling Tang 《PloS one》2013,8(8)
Background
Inhaled bronchodilators are the first-line therapy for COPD. Indacaterol is a novel addition to existing long-acting bronchodilators.Objectives
Systematic review of randomized controlled trials (RCT) on efficacy and safety of indacaterol as compared: 1) with placebo at different dosages, 2) with existing bronchodilators; (3) as add-on treatment to tiotropium.Methods
We searched 13 electronic databases, including MEDLINE, EMBASE and CENTRAL, and contacted the manufacturer for unpublished data. Primary outcome was mean FEV1 change at 12th week, secondary outcomes included changes in SGRQ, TDI and BODE index at 6 months, exacerbation at 1 year, and worsening of symptoms.Results
Twelve eligible RCTs of moderate risk of bias included data from 10,977 patients. Compared to placebo, indacaterol improved FEV1 by a weighted mean difference (WMD) of 0.16 L (95%CI: 0.15, 0.18 L, p<0.001), homogeneously above the minimally important difference of 0.10 L. It offered clinically relevant improvement in all secondary outcomes except exacerbation. Magnitude of benefit did not differ significantly by dosage, but one treatment related death was reported at 300 ug. Efficacy of Indacaterol was similar to formoterol and salmeterol (FEV1 WMD = 0.04L, 95%CI: 0.01L, 0.07 L, p = 0.02); and tiotropium (FEV1 WMD = 0.01L, 95%CI: −0.01, 0.03L, p = 0.61). The use of indacaterol on top of tiotropium yielded additional improvement on FEV1 (WMD = 0.07 L, 95%CI: 0.05L, 0.10 L, p<0.001).Conclusion
Indacaterol is safe and beneficial for patients with COPD at dosage ≤150 ug. It may serve as a good alternative to existing bronchodilators, or as an add-on to tiotropium for unresponsive patients. Use of higher dosage requires further justification. 相似文献107.
108.
Meares GP Hughes KJ Naatz A Papa FR Urano F Hansen PA Benveniste EN Corbett JA 《Molecular and cellular biology》2011,31(21):4286-4297
While there can be detrimental consequences of nitric oxide production at pathological concentrations, eukaryotic cells have evolved protective mechanisms to defend themselves against this damage. The unfolded-protein response (UPR), activated by misfolded proteins and oxidative stress, is one adaptive mechanism that is employed to protect cells from stress. Nitric oxide is a potent activator of AMP-activated protein kinase (AMPK), and AMPK participates in the cellular defense against nitric oxide-mediated damage in pancreatic β-cells. In this study, the mechanism of AMPK activation by nitric oxide was explored. The known AMPK kinases LKB1, CaMKK, and TAK1 are not required for the activation of AMPK by nitric oxide. Instead, this activation is dependent on the endoplasmic reticulum (ER) stress-activated protein IRE1. Nitric oxide-induced AMPK phosphorylation and subsequent signaling to AMPK substrates, including Raptor, acetyl coenzyme A carboxylase, and PGC-1α, is attenuated in IRE1α-deficient cells. The endoribonuclease activity of IRE1 appears to be required for AMPK activation in response to nitric oxide. In addition to nitric oxide, stimulation of IRE1 endoribonuclease activity with the flavonol quercetin leads to IRE1-dependent AMPK activation. These findings indicate that the RNase activity of IRE1 participates in AMPK activation and subsequent signaling through multiple AMPK-dependent pathways in response to nitrosative stress. 相似文献
109.
Bluetongue virus (BTV), a member of the Reoviridae family, is an insect-borne animal pathogen. Virus release from infected cells is predominantly by cell lysis, but some BTV particles are also released from the plasma membrane. The nonstructural protein NS3 has been implicated in this process. Using alternate initiator methionine residues, NS3 is expressed as a full-length protein and as a truncated variant that lacks the initial 13 residues, which, by yeast-two hybrid analyses, have been shown to interact with a cellular trafficking protein S100A10/p11. To understand the physiological significance of this interaction in virus-infected cells, we have used reverse genetics to investigate the roles of NS3 and NS3A in virus replication and localization in both mammalian and insect vector-derived cells. A virus expressing NS3 but not NS3A was able to propagate in and release from mammalian cells efficiently. However, growth of a mutant virus expressing only NS3A was severely attenuated, although protein expression, replication, double-stranded RNA (dsRNA) synthesis, and particle assembly in the cytoplasm were observed. Two of three single-amino-acid substitutions in the N-terminal 13 residues of NS3 showed phenotypically similar effects. Pulldown assay and confocal microscopy demonstrated a lack of interaction between NS3 and S100A10/p11 in mutants with poor replication. The role of NS3/NS3A was also assessed in insect cells where virus grew, albeit with a reduced titer. Notably, however, while wild-type particles were found within cytoplasmic vesicles in insect cells, mutant viruses were scattered throughout the cytoplasm and not confined to vesicles. These results provide support for a role for the extreme amino terminus of NS3 in the late stages of virus growth in mammalian cells, plausibly in egress. However, both NS3 and NS3A were required for efficient BTV growth in insect cells. 相似文献
110.
The present review of the satiating effect of cholecystokinin in humans has revealed that cholecystokinin is a physiological satiety factor in humans. The results demonstrate the efficacy of the satiating actions of exogenous and endogenous CCK in humans. The therapeutic potential of CCK analogues cannot be estimated until further studies are performed that demonstrate the efficacy of CCK analogues for decreasing body weight, and the safety of CCK when administered repetitively for prolonged periods. 相似文献