192 research outputs found
Activation of Interferon Regulatory Factor 5 by Site Specific Phosphorylation
The cellular defense to infection depends on accurate activation of transcription factors and expression of select innate immunity genes. Interferon regulatory factor 5 (IRF5), a risk factor for systemic lupus erythematosus, is activated in response to pathogen recognition receptor engagement and downstream effector molecules. We find the nucleotide-binding oligomerization domain containing protein 2 (NOD2) receptor to be a significant activator of IRF5. Phosphorylation is key to the regulation of IRF5, but the precise phosphorylation sites in IRF5 remained to be identified. We used mass spectrometry to identify for the first time specific residues that are phosphorylated in response to TANK-binding kinase-1 (TBK-1), tumor necrosis factor receptor-associated factor 6 (TRAF6), or receptor interacting protein 2 (RIP2). RIP2, a kinase known to function downstream of NOD2, was the most effective activator of IRF5-regulated gene expression. To determine if the phosphorylated residues are required or sufficient for IRF5 activity, aspartic acid phosphomimetic substitutions or inactivating alanine substitutions were tested. Phosphorylation of carboxyl serines 451 and 462 appear the primary trigger of IRF5 function in nuclear accumulation, transcription, and apoptosis. Results indicate polyubiquitination of IRF5 does not play a major role in its transcriptional activity, and that ubiquitination and phosphorylation are independent modifications
Associations between alcohol, smoking, and cartilage composition and knee joint morphology: Data from the Osteoarthritis Initiative
Summary: Objective: To determine the cross-sectional associations of alcohol consumption and smoking history with magnetic resonance imaging (MRI) measures of cartilage composition (T2) and joint structure using data from the Osteoarthritis Initiative (OAI). Design: Subjects with radiographic Kellgren Lawrence right knee grades 0–2 were selected from the OAI database, and those with previously analyzed MRI cartilage T2 and semi-quantitative joint morphology gradings (WORMS) were included (n ​= ​2061). Alcohol consumption was categorized as: no drinks to 7 drinks/week. Smoking history was categorized as none, current, or former. Linear regression was used to assess the relationships of alcohol consumption and smoking history with both WORMS scores and cartilage T2. Results: Subjects who consumed >7 drinks/week had significantly higher cartilage T2 than subjects who consumed 7 drinks/week was associated with elevated cartilage T2. Compared to non-smokers, current smokers had a more degenerated cartilage matrix as evidenced by greater cartilage T2
T2-Weighted Dixon Turbo Spin Echo for Accelerated Simultaneous Grading of Whole-Body Skeletal Muscle Fat Infiltration and Edema in Patients With Neuromuscular Diseases
Objective The assessment of fatty infiltration and edema in the musculature of patients with neuromuscular diseases (NMDs) typically requires the separate performance of T-1-weighted and fat-suppressed T-2-weighted sequences. T-2-weighted Dixon turbo spin echo (TSE) enables the generation of T-2-weighted fat- and water-separated images, which can be used to assess both pathologies simultaneously. The present study examines the diagnostic performance of T-2-weighted Dixon TSE compared with the standard sequences in 10 patients with NMDs and 10 healthy subjects. Methods Whole-body magnetic resonance imaging was performed including T-1-weighted Dixon fast field echo, T-2-weighted short-tau inversion recovery, and T-2-weighted Dixon TSE. Fatty infiltration and intramuscular edema were rated by 2 radiologists using visual semiquantitative rating scales. To assess intermethod and interrater agreement, weighted Cohen's coefficients were calculated. Results The ratings of fatty infiltration showed high intermethod and high interrater agreement (T-1-weighted Dixon fast field echo vs T-2-weighted Dixon TSE fat image). The evaluation of edematous changes showed high intermethod and good interrater agreement (T-2-weighted short-tau inversion recovery vs T-2-weighted Dixon TSE water image). Conclusions T-2-weighted Dixon TSE imaging is an alternative for accelerated simultaneous grading of whole-body skeletal muscle fat infiltration and edema in patients with NMDs
Differentiation of benign and malignant vertebral fractures using a convolutional neural network to extract CT-based texture features.
PURPOSE
To assess the diagnostic performance of three-dimensional (3D) CT-based texture features (TFs) using a convolutional neural network (CNN)-based framework to differentiate benign (osteoporotic) and malignant vertebral fractures (VFs).
METHODS
A total of 409 patients who underwent routine thoracolumbar spine CT at two institutions were included. VFs were categorized as benign or malignant using either biopsy or imaging follow-up of at least three months as standard of reference. Automated detection, labelling, and segmentation of the vertebrae were performed using a CNN-based framework ( https://anduin.bonescreen.de ). Eight TFs were extracted: Varianceglobal, Skewnessglobal, energy, entropy, short-run emphasis (SRE), long-run emphasis (LRE), run-length non-uniformity (RLN), and run percentage (RP). Multivariate regression models adjusted for age and sex were used to compare TFs between benign and malignant VFs.
RESULTS
Skewnessglobal showed a significant difference between the two groups when analyzing fractured vertebrae from T1 to L6 (benign fracture group: 0.70 [0.64-0.76]; malignant fracture group: 0.59 [0.56-0.63]; and p = 0.017), suggesting a higher skewness in benign VFs compared to malignant VFs.
CONCLUSION
Three-dimensional CT-based global TF skewness assessed using a CNN-based framework showed significant difference between benign and malignant thoracolumbar VFs and may therefore contribute to the clinical diagnostic work-up of patients with VFs
Differentiation of benign and malignant vertebral fractures using a convolutional neural network to extract CT-based texture features
Amplification dynamics of platy-1 retrotransposons in the cebidae platyrrhine lineage
© 2019 The Author(s). Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. Platy-1 elements are Platyrrhine-specific, short interspersed elements originally discovered in the Callithrix jacchus (common marmoset) genome. To date,only themarmoset genomehas been analyzed for Platy-1 repeat content.Here,we report full-length Platy-1 insertions in other NewWorld monkey (NWM) genomes (Saimiri boliviensis, squirrel monkey; Cebus imitator, capuchin monkey; and Aotus nancymaae, owl monkey) and analyze the amplification dynamics of lineage-specific Platy-1 insertions. A relatively small number of full-length and lineage-specific Platy-1 elements were found in the squirrel, capuchin, and owl monkey genomes compared with the marmoset genome. In addition, only a few older Platy-1 subfamilies were recovered in this study, with no Platy-1 subfamilies younger than Platy-1-6. By contrast, 62 Platy-1 subfamilieswere discovered in themarmoset genome.All of the lineagespecific insertions found in the squirrel and capuchin monkeys were fixed present. However, 15%of the lineage-specific Platy-1 loci in Aotus were polymorphic for insertion presence/absence. In addition, two new Platy-1 subfamilies were identified in the owl monkey genome with low nucleotide divergences compared with their respective consensus sequences, suggesting minimal ongoing retrotransposition in the Aotus genus and no current activity in the Saimiri, Cebus, and Sapajus genera. These comparative analyses highlight the finding that the high number of Platy-1 elements discovered in themarmoset genome is an exception among NWManalyzed thus far, rather than the rule. Future studies are needed to expand upon our knowledge of Platy-1 amplification in other NWM genomes
Overfitting Affects the Reliability of Radial Velocity Mass Estimates of the V1298 Tau Planets
Mass, radius, and age measurements of young (<100 Myr) planets have the power
to shape our understanding of planet formation. However, young stars tend to be
extremely variable in both photometry and radial velocity, which makes
constraining these properties challenging. The V1298 Tau system of four ~0.5
Rjup planets transiting a pre-main sequence star presents an important, if
stress-inducing, opportunity to directly observe and measure the properties of
infant planets. Su\'arez-Mascare\~no et al. (2021) published
radial-velocity-derived masses for two of the V1298 Tau planets using a
state-of-the-art Gaussian Process regression framework. The planetary densities
computed from these masses were surprisingly high, implying extremely rapid
contraction after formation in tension with most existing planet formation
theories. In an effort to further constrain the masses of the V1298 Tau
planets, we obtained 36 RVs using Keck/HIRES, and analyzed them in concert with
published RVs and photometry. Through performing a suite of cross validation
tests, we found evidence that the preferred model of SM21 suffers from
overfitting, defined as the inability to predict unseen data, rendering the
masses unreliable. We detail several potential causes of this overfitting, many
of which may be important for other RV analyses of other active stars, and
recommend that additional time and resources be allocated to understanding and
mitigating activity in active young stars such as V1298 Tau.Comment: 26 pages, 12 figures; published in A
Aptamer-based multiplexed proteomic technology for biomarker discovery
Interrogation of the human proteome in a highly multiplexed and efficient manner remains a coveted and challenging goal in biology. We present a new aptamer-based proteomic technology for biomarker discovery capable of simultaneously measuring thousands of proteins from small sample volumes (15 [mu]L of serum or plasma). Our current assay allows us to measure ~800 proteins with very low limits of detection (1 pM average), 7 logs of overall dynamic range, and 5% average coefficient of variation. This technology is enabled by a new generation of aptamers that contain chemically modified nucleotides, which greatly expand the physicochemical diversity of the large randomized nucleic acid libraries from which the aptamers are selected. Proteins in complex matrices such as plasma are measured with a process that transforms a signature of protein concentrations into a corresponding DNA aptamer concentration signature, which is then quantified with a DNA microarray. In essence, our assay takes advantage of the dual nature of aptamers as both folded binding entities with defined shapes and unique sequences recognizable by specific hybridization probes. To demonstrate the utility of our proteomics biomarker discovery technology, we applied it to a clinical study of chronic kidney disease (CKD). We identified two well known CKD biomarkers as well as an additional 58 potential CKD biomarkers. These results demonstrate the potential utility of our technology to discover unique protein signatures characteristic of various disease states. More generally, we describe a versatile and powerful tool that allows large-scale comparison of proteome profiles among discrete populations. This unbiased and highly multiplexed search engine will enable the discovery of novel biomarkers in a manner that is unencumbered by our incomplete knowledge of biology, thereby helping to advance the next generation of evidence-based medicine
- …