Phosphatidylinositol 3-kinase (PI3K) promotes cancer cell survival, migration, growth and proliferation by generating phosphatidylinositol 3,4,5-trisphosphate (PIP3) in the inner leaflet of the ...plasma membrane. PIP3 recruits pleckstrin homology domain-containing proteins to the membrane to activate oncogenic signaling cascades. Anticancer therapeutics targeting the PI3K/AKT/mTOR (mammalian target of rapamycin) pathway are in clinical development. In a mass spectrometric screen to identify PIP3-regulated proteins in breast cancer cells, levels of the Rac activator PIP3-dependent Rac exchange factor-1 (P-REX1) increased in response to PI3K inhibition, and decreased upon loss of the PI3K antagonist phosphatase and tensin homolog (PTEN). P-REX1 mRNA and protein levels were positively correlated with ER expression, and inversely correlated with PI3K pathway activation in breast tumors as assessed by gene expression and phosphoproteomic analyses. P-REX1 increased activation of Rac1, PI3K/AKT and MEK/ERK signaling in a PTEN-independent manner, and promoted cell and tumor viability. Loss of P-REX1 or inhibition of Rac suppressed PI3K/AKT and MEK/ERK, and decreased viability. P-REX1 also promoted insulin-like growth factor-1 receptor activation, suggesting that P-REX1 provides positive feedback to activators upstream of PI3K. In support of a model where PIP3-driven P-REX1 promotes both PI3K/AKT and MEK/ERK signaling, high levels of P-REX1 mRNA (but not phospho-AKT or a transcriptomic signature of PI3K activation) were predictive of sensitivity to PI3K inhibitors among breast cancer cell lines. P-REX1 expression was highest in estrogen receptor-positive breast tumors compared with many other cancer subtypes, suggesting that neutralizing the P-REX1/Rac axis may provide a novel therapeutic approach to selectively abrogate oncogenic signaling in breast cancer cells.
Hong Kong employed a strategy of intermittent public health and social measures alongside increasingly stringent travel regulations to eliminate domestic SARS-CoV-2 transmission. By analyzing 1899 ...genome sequences (>18% of confirmed cases) from 23-January-2020 to 26-January-2021, we reveal the effects of fluctuating control measures on the evolution and epidemiology of SARS-CoV-2 lineages in Hong Kong. Despite numerous importations, only three introductions were responsible for 90% of locally-acquired cases. Community outbreaks were caused by novel introductions rather than a resurgence of circulating strains. Thus, local outbreak prevention requires strong border control and community surveillance, especially during periods of less stringent social restriction. Non-adherence to prolonged preventative measures may explain sustained local transmission observed during wave four in late 2020 and early 2021. We also found that, due to a tight transmission bottleneck, transmission of low-frequency single nucleotide variants between hosts is rare.
Hong Kong experienced a surge of Omicron BA.2 infections in early 2022, resulting in one of the highest per-capita death rates of COVID-19. The outbreak occurred in a dense population with low ...immunity towards natural SARS-CoV-2 infection, high vaccine hesitancy in vulnerable populations, comprehensive disease surveillance and the capacity for stringent public health and social measures (PHSMs). By analyzing genome sequences and epidemiological data, we reconstructed the epidemic trajectory of BA.2 wave and found that the initial BA.2 community transmission emerged from cross-infection within hotel quarantine. The rapid implementation of PHSMs suppressed early epidemic growth but the effective reproduction number (R
) increased again during the Spring festival in early February and remained around 1 until early April. Independent estimates of point prevalence and incidence using phylodynamics also showed extensive superspreading at this time, which likely contributed to the rapid expansion of the epidemic. Discordant inferences based on genomic and epidemiological data underscore the need for research to improve near real-time epidemic growth estimates by combining multiple disparate data sources to better inform outbreak response policy.
Accurate prediction of charge carrier relaxation rates is essential to design molecules and materials with the desired photochemical properties for applications like photocatalysis and solar energy ...conversion. Nonadiabatic molecular dynamics allows one to simulate the relaxation process of excited charge carriers. Plane-wave density functional theory (DFT) calculations make the time-derivative nonadiabatic couplings (TNACs) simple to compute because the basis is independent of the atomic positions. However, the effect of the kinetic energy cutoff for the plane-wave basis on the accuracy of the dynamics has not been studied. Here, we examine the effect of the kinetic energy cutoff on the TNACs and decay time scales for the prototypical model system of tetracene. These calculations show that the choice of kinetic energy cutoff can change the relaxation time by up to 30%. The relaxation times of states that have small TNACs to other states or are far from degenerate are more sensitive to the kinetic energy cutoff than those of states with large TNACs or near degeneracies. A kinetic energy cutoff of 60 Ry is sufficient for all states to reach semiquantitative agreement (absolute error <10%) with the decay times of our 110 Ry reference data, and a cutoff of 80 Ry is required for all states to reach quantitative agreement (absolute error <2%).
RNA interference (RNAi) has recently emerged as a specific and efficient method to silence gene expression in mammalian cells either by transfection of short interfering RNAs (siRNAs; ref. 1) or, ...more recently, by transcription of short hairpin RNAs (shRNAs) from expression vectors and retroviruses. But the resistance of important cell types to transduction by these approaches, both in vitro and in vivo, has limited the use of RNAi. Here we describe a lentiviral system for delivery of shRNAs into cycling and non-cycling mammalian cells, stem cells, zygotes and their differentiated progeny. We show that lentivirus-delivered shRNAs are capable of specific, highly stable and functional silencing of gene expression in a variety of cell types and also in transgenic mice. Our lentiviral vectors should permit rapid and efficient analysis of gene function in primary human and animal cells and tissues and generation of animals that show reduced expression of specific genes. They may also provide new approaches for gene therapy.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
RATIONALE:Coronary artery disease (CAD) is a major cause of morbidity and mortality worldwide. Recent genome-wide association studies revealed 163 loci associated with CAD. However, the precise ...molecular mechanisms by which the majority of these loci increase CAD risk are not known. Vascular smooth muscle cells (VSMCs) are critical in the development of CAD. They can play either beneficial or detrimental roles in lesion pathogenesis, depending on the nature of their phenotypic changes.
OBJECTIVE:To identify genetic variants associated with atherosclerosis-relevant phenotypes in VSMCs.
METHODS AND RESULTS:We quantified 12 atherosclerosis-relevant phenotypes related to calcification, proliferation, and migration in VSMCs isolated from 151 multiethnic heart transplant donors. After genotyping and imputation, we performed association mapping using 6.3 million genetic variants. We demonstrated significant variations in calcification, proliferation, and migration. These phenotypes were not correlated with each other. We performed genome-wide association studies for 12 atherosclerosis-relevant phenotypes and identified 4 genome-wide significant loci associated with at least one VSMC phenotype. We overlapped the previously identified CAD loci with our data set and found nominally significant associations at 79 loci. One of them was the chromosome 1q41 locus, which harbors MIA3. The G allele of the lead risk single nucleotide polymorphism (SNP) rs67180937 was associated with lower VSMC MIA3 expression and lower proliferation. Lentivirus-mediated silencing of MIA3 (melanoma inhibitory activity protein 3) in VSMCs resulted in lower proliferation, consistent with human genetics findings. Furthermore, we observed a significant reduction of MIA3 protein in VSMCs in thin fibrous caps of late-stage atherosclerotic plaques compared to early fibroatheroma with thick and protective fibrous caps in mice and humans.
CONCLUSIONS:Our data demonstrate that genetic variants have significant influences on VSMC function relevant to the development of atherosclerosis. Furthermore, high MIA3 expression may promote atheroprotective VSMC phenotypic transitions, including increased proliferation, which is essential in the formation or maintenance of a protective fibrous cap.
Summary
Background and objective
The allergenicity of several German cockroach (Bla‐g) antigens at the level of IgE responses is well established. However, less is known about the specificity of CD4+ ...TH responses, and whether differences exist in associated magnitude or cytokine profiles as a function of disease severity.
Methods
Proteomic and transcriptomic techniques were used to identify novel antigens recognized by allergen‐specific T cells. To characterize different TH functionalities of allergen‐specific T cells, ELISPOT assays with sets of overlapping peptides covering the sequences of known allergens and novel antigens were employed to measure release of IL‐5, IFNγ, IL‐10, IL‐17 and IL‐21.
Results
Using these techniques, we characterized TH responses in a cohort of adult Bla‐g‐sensitized subjects, either with (n = 55) or without (n = 17) asthma, and nonsensitized controls (n = 20). T cell responses were detected for ten known Bla‐g allergens and an additional ten novel Bla‐g antigens, representing in total a 5‐fold increase in the number of antigens demonstrated to be targeted by allergen‐specific T cells. Responses of sensitized individuals regardless of asthma status were predominantly TH2, but higher in patients with diagnosed asthma. In asthmatic subjects, Bla‐g 5, 9 and 11 were immunodominant, while, in contrast, nonasthmatic‐sensitized subjects responded mostly to Bla‐g 5 and 4 and the novel antigen NBGA5.
Conclusions
Asthmatic and nonasthmatic cockroach‐sensitized individuals exhibit similar TH2‐polarized responses. Compared with nonasthmatics, however, asthmatic individuals have responses of higher magnitude and different allergen specificity.
Dairy farms in Ireland are expanding in preparation for a new era of unrestricted milk production with the elimination of the European Union (EU) production quotas in 2015. Countries experiencing a ...changing agricultural demographic, including farm expansion, can benefit from documenting the implementation of on-farm biosecurity. The objectives of this study were to document and describe influences on biosecurity practices and related opinions on dairy farms. A representative response rate of 64% was achieved to a nationwide telesurvey of farmers.
A 20% discrepancy was found between self-declared and truly ‘closed’ herds indicating a lack of understanding of the closed herd concept. Although >72% of farmers surveyed considered biosecurity to be important, 53% stated that a lack of information might prevent them from improving their biosecurity. Logistic regression highlighted regional, age, and farm-size related differences in biosecurity practices and opinions towards its implementation. Farmers in the most dairy cattle dense region were three times more likely to quarantine purchased stock than were their equivalents in regions where dairy production was less intense (P=0.012). Younger farmers in general were over twice as likely as middle-aged farmers to implement biosecurity guidelines (P=0.026). The owners of large enterprises were almost five times more likely to join a voluntary animal health scheme (P=0.003), and were over three times more likely to pay a premium price for health accredited animals (P=0.02) than were those farming small holdings. The baseline data recorded in this survey will form the basis for more detailed sociological and demographic research which will facilitate the targeting of future training of the farming community in biosecurity.
Coronary artery disease (CAD) is the leading cause of death worldwide. Recent meta-analyses of genome-wide association studies have identified over 175 loci associated with CAD. The majority of these ...loci are in noncoding regions and are predicted to regulate gene expression. Given that vascular smooth muscle cells (SMCs) play critical roles in the development and progression of CAD, we aimed to identify the subset of the CAD loci associated with the regulation of transcription in distinct SMC phenotypes.
We measured gene expression in SMCs isolated from the ascending aortas of 151 heart transplant donors of various genetic ancestries in quiescent or proliferative conditions and calculated the association of their expression and splicing with ~6.3 million imputed single-nucleotide polymorphism markers across the genome.
We identified 4910 expression and 4412 splicing quantitative trait loci (sQTLs) representing regions of the genome associated with transcript abundance and splicing. A total of 3660 expression quantitative trait loci (eQTLs) had not been observed in the publicly available Genotype-Tissue Expression dataset. Further, 29 and 880 eQTLs were SMC-specific and sex-biased, respectively. We made these results available for public query on a user-friendly website. To identify the effector transcript(s) regulated by CAD loci, we used 4 distinct colocalization approaches. We identified 84 eQTL and 164 sQTL that colocalized with CAD loci, highlighting the importance of genetic regulation of mRNA splicing as a molecular mechanism for CAD genetic risk. Notably, 20% and 35% of the eQTLs were unique to quiescent or proliferative SMCs, respectively. One CAD locus colocalized with a sex-specific eQTL (
), and another locus colocalized with SMC-specific eQTL (
). The most significantly associated CAD locus, 9p21, was an sQTL for the long noncoding RNA
, also known as
, in proliferative SMCs.
Collectively, our results provide evidence for the molecular mechanisms of genetic susceptibility to CAD in distinct SMC phenotypes.
Abstract
Advertisers often use specifically chosen wording to convey the effectiveness of their product and we investigated memory accuracy for the scientific claims put forth by product ...advertisements. Participants were shown a cognitive enhancement product advertisement and were tested on their memory for various details. Critically, we were interested in participants' memory for a phrase describing the product as either “clinically proven” (indicating the product is effective) or “clinically studied” (which is ambiguous). Generally, both younger and older adults demonstrated poor memory for this detail and were more likely to remember the product as having been “proven” to be effective than to have been “studied”. Thus, we demonstrate the fallibility of memory and the potential for reliance on schematic knowledge in the absence of a veridical record of one's memory for the advertisement. We suggest that ambiguous efficacy claims be carefully considered by consumers so as not to be misled.
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