611 research outputs found
Pathophysiological regulation of lung function by the free fatty acid receptor FFA4.
Increased prevalence of inflammatory airway diseases including asthma and chronic obstructive pulmonary disease (COPD) together with inadequate disease control by current frontline treatments means that there is a need to define therapeutic targets for these conditions. Here, we investigate a member of the G protein-coupled receptor family, FFA4, that responds to free circulating fatty acids including dietary omega-3 fatty acids found in fish oils. We show that FFA4, although usually associated with metabolic responses linked with food intake, is expressed in the lung where it is coupled to Gq/11 signaling. Activation of FFA4 by drug-like agonists produced relaxation of murine airway smooth muscle mediated at least in part by the release of the prostaglandin E2 (PGE2) that subsequently acts on EP2 prostanoid receptors. In normal mice, activation of FFA4 resulted in a decrease in lung resistance. In acute and chronic ozone models of pollution-mediated inflammation and house dust mite and cigarette smoke-induced inflammatory disease, FFA4 agonists acted to reduce airway resistance, a response that was absent in mice lacking expression of FFA4. The expression profile of FFA4 in human lung was similar to that observed in mice, and the response to FFA4/FFA1 agonists similarly mediated human airway smooth muscle relaxation ex vivo. Our study provides evidence that pharmacological targeting of lung FFA4, and possibly combined activation of FFA4 and FFA1, has in vivo efficacy and might have therapeutic value in the treatment of bronchoconstriction associated with inflammatory airway diseases such as asthma and COPD
What is the valence of a correlated solid? The double life of delta-plutonium
Plutonium displays phase transitions with enormous volume differences among
its phases and both its Pauli like magnetic susceptibility and resistivity are
an order of magnitude larger than those of simple metals. Curium is also highly
resistive but its susceptibility is Curie-like at high temperatures and orders
antiferromagnetically at low temperatures. The anomalous properties of the late
actinides stem from the competition between the itinerancy and localization of
its f electrons, which makes the late actinides elemental strongly correlated
materials. A central problem in this field is to understand the mechanism by
which these materials resolve these conflicting tendencies. In this letter we
identify the electronic mechanisms responsible for the anomalous behaviour of
late actinides. We revisit the concept of valence using theoretical approach
that treats magnetism, Kondo screening, atomic multiplet effects, spin orbit
coupling and crystal field splitting on the same footing. Plutonium is found to
be in a rare mixed valent state, namely its ground state is a superposition of
two distinct valencies. Curium settles in a single valence magnetically ordered
state at low temperatures. The f7 atomic configuration of Curium is contrasted
with the multiple configuration manifolds present in Plutonium ground state
which we characterize by a valence histogram. The balance between the Kondo
screening and magnetism is determined by the competition between spin orbit
coupling and the strength of atomic multiplets which is in turn regulated by
the degree of itinerancy. The approach presented here, highlights the
electronic origin of the bonding anomalies in plutonium and can be applied to
predict generalized valences and the presence or absence of magnetism in other
compounds starting from first principles.Comment: 2 figures, 1 tabl
M1 muscarinic allosteric modulators slow prion neurodegeneration and restore memory loss
This is the final version of the article. Available from American Society for Clinical Investigation via the DOI in this record.The current frontline symptomatic treatment for Alzheimer’s disease (AD) is whole-body upregulation of cholinergic
transmission via inhibition of acetylcholinesterase. This approach leads to profound dose-related adverse effects. An
alternative strategy is to selectively target muscarinic acetylcholine receptors, particularly the M1 muscarinic acetylcholine
receptor (M1 mAChR), which was previously shown to have procognitive activity. However, developing M1 mAChR–selective orthosteric ligands has proven challenging. Here, we have shown that mouse prion disease shows many of the hallmarks
of human AD, including progressive terminal neurodegeneration and memory deficits due to a disruption of hippocampal
cholinergic innervation. The fact that we also show that muscarinic signaling is maintained in both AD and mouse prion
disease points to the latter as an excellent model for testing the efficacy of muscarinic pharmacological entities. The memory deficits we observed in mouse prion disease were completely restored by treatment with benzyl quinolone carboxylic acid (BQCA) and benzoquinazoline-12 (BQZ-12), two highly selective positive allosteric modulators (PAMs) of M1 mAChRs. Furthermore, prolonged exposure to BQCA markedly extended the lifespan of diseased mice. Thus, enhancing hippocampal muscarinic signaling using M1 mAChR PAMs restored memory loss and slowed the progression of mouse prion disease, indicating that this ligand type may have clinical benefit in diseases showing defective cholinergic transmission, such as AD.ABT, AC, and PMS received funding from a Wellcome Trust Collaborative
Award (201529/Z/16/Z). ABT, SJB, AJB, and TMH were
funded through a Medical Research Council programme leader
grant provided by the MRC Toxicology Unit. CCF, LMB, AJM, and
HES were funded by the Eli Lilly Company. JMB received funding
through a Lilly Research Award Program (LRAP) grant (Eli
Lilly). RP received funding from the Marie Curie grant “Extrabrain”
(European Commission). AC is a senior principal research
fellow and PMS a principal research fellow of the National Health
and Medical Research Council of Australia. Tissue samples were
from Randy Woltjer at the Oregon Alzheimer’s Disease Center.
The Oregon Alzheimer’s Disease Center is supported by NIH grant P30AG008017
Multiple Independent Genetic Factors at NOS1AP Modulate the QT Interval in a Multi-Ethnic Population
Extremes of electrocardiographic QT interval are associated with increased risk for sudden cardiac death (SCD); thus, identification and characterization of genetic variants that modulate QT interval may elucidate the underlying etiology of SCD. Previous studies have revealed an association between a common genetic variant in NOS1AP and QT interval in populations of European ancestry, but this finding has not been extended to other ethnic populations. We sought to characterize the effects of NOS1AP genetic variants on QT interval in the multi-ethnic population-based Dallas Heart Study (DHS, n = 3,072). The SNP most strongly associated with QT interval in previous samples of European ancestry, rs16847548, was the most strongly associated in White (P = 0.005) and Black (P = 3.6×10−5) participants, with the same direction of effect in Hispanics (P = 0.17), and further showed a significant SNP × sex-interaction (P = 0.03). A second SNP, rs16856785, uncorrelated with rs16847548, was also associated with QT interval in Blacks (P = 0.01), with qualitatively similar results in Whites and Hispanics. In a previously genotyped cohort of 14,107 White individuals drawn from the combined Atherosclerotic Risk in Communities (ARIC) and Cardiovascular Health Study (CHS) cohorts, we validated both the second locus at rs16856785 (P = 7.63×10−8), as well as the sex-interaction with rs16847548 (P = 8.68×10−6). These data extend the association of genetic variants in NOS1AP with QT interval to a Black population, with similar trends, though not statistically significant at P<0.05, in Hispanics. In addition, we identify a strong sex-interaction and the presence of a second independent site within NOS1AP associated with the QT interval. These results highlight the consistent and complex role of NOS1AP genetic variants in modulating QT interval
Study of decays to the final state and evidence for the decay
A study of decays is performed for the first time
using data corresponding to an integrated luminosity of 3.0
collected by the LHCb experiment in collisions at centre-of-mass energies
of and TeV. Evidence for the decay
is reported with a significance of 4.0 standard deviations, resulting in the
measurement of
to
be .
Here denotes a branching fraction while and
are the production cross-sections for and mesons.
An indication of weak annihilation is found for the region
, with a significance of
2.4 standard deviations.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-022.html,
link to supplemental material inserted in the reference
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Convective self-aggregation in numerical simulations: a review
Organized convection in the Tropics occurs across a range of spatial and temporal scales and strongly influences cloud cover and humidity. One mode of organization found is “self-aggregation”, in which moist convection spontaneously organizes into one or several isolated clusters despite spatially homogeneous boundary conditions and forcing. Self-aggregation is driven by interactions between clouds, moisture, radiation, surface fluxes, and circulation, and occurs in a wide variety of idealized simulations of radiative-convective equilibrium. Here we provide a review of convective self-aggregation in numerical simulations, including its character, causes, and effects. We describe the evolution of self-aggregation including its time and length scales and the physical mechanisms leading to its triggering and maintenance, and we also discuss possible links to climate and climate change
GWAS for discovery and replication of genetic loci associated with sudden cardiac arrest in patients with coronary artery disease
<p>Abstract</p> <p>Background</p> <p>Epidemiologic evidence suggests a heritable component to risk for sudden cardiac arrest independent of risk for myocardial infarction. Recent candidate gene association studies for community sudden cardiac arrests have focused on a limited number of biological pathways and yielded conflicting results. We sought to identify novel gene associations for sudden cardiac arrest in patients with coronary artery disease by performing a genome-wide association study.</p> <p>Methods</p> <p>Tagging SNPs (n = 338,328) spanning the genome were typed in a case-control study comparing 89 patients with coronary artery disease and sudden cardiac arrest due to ventricular tachycardia or ventricular fibrillation to 520 healthy controls.</p> <p>Results</p> <p>Fourteen SNPs including 7 SNPs among 7 genes (ACYP2, AP1G2, ESR1, DGES2, GRIA1, KCTD1, ZNF385B) were associated with sudden cardiac arrest (all p < 1.30 × 10<sup>-7</sup>), following Bonferroni correction and adjustment for population substructure, age, and sex; genetic variation in ESR1 (p = 2.62 × 10<sup>-8</sup>; Odds Ratio [OR] = 1.43, 95% confidence interval [CI]:1.277, 1.596) has previously been established as a risk factor for cardiovascular disease. In tandem, the role of 9 genes for monogenic long QT syndrome (LQT1-9) was assessed, yielding evidence of association with CACNA1C (LQT8; p = 3.09 × 10<sup>-4</sup>; OR = 1.18, 95% CI:1.079, 1.290). We also assessed 4 recently published gene associations for sudden cardiac arrest, validating NOS1AP (p = 4.50 × 10<sup>-2</sup>, OR = 1.15, 95% CI:1.003, 1.326), CSMD2 (p = 6.6 × 10<sup>-3</sup>, OR = 2.27, 95% CI:1.681, 2.859), and AGTR1 (p = 3.00 × 10<sup>-3</sup>, OR = 1.13, 95% CI:1.042, 1.215).</p> <p>Conclusion</p> <p>We demonstrate 11 gene associations for sudden cardiac arrest due to ventricular tachycardia/ventricular fibrillation in patients with coronary artery disease. Validation studies in independent cohorts and functional studies are required to confirm these associations.</p
Upregulation of bfl-1 is a potential mechanism of chemoresistance in B-cell chronic lymphocytic leukaemia
B-cell chronic lymphocytic leukaemia (B-CLL) is characterised by the progressive accumulation of monoclonal CD5+ B cells. In a previous study, we have analysed the expression profile of apoptosis-regulating genes using a cDNA-based microarray and found overexpression of the antiapoptotic bcl-2 family member, bfl-1, in B-CLL cells with an apoptosis-resistant phenotype. In this study, bfl-1 mRNA levels have been determined by competitive PCR in an extended population of B-CLL patients to characterise its role in disease progression and development of chemoresistance. bfl-1 levels were significantly higher in patients with no response (NR) to last chemotherapy than in patients responding (partial response (PR)) to last chemotherapy (P<0.05) and in patients who had not required treatment (P<0.05). We found no correlation between bfl-1 mRNA levels and disease progression, IGHV mutational status or other clinical parameters. In addition, bfl-1 mRNA levels were inversely correlated with apoptotic response to in vitro fludarabine treatment of B-CLL cells. Specific downregulation of bfl-1 using siRNA induced apoptosis in resistant cells. Our data suggest that bfl-1 contributes to chemoresistance and might be a therapeutic target in B-CLL
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