2,673 research outputs found
PexRAP inhibits PRDM16-mediated thermogenic gene expression
How the nuclear receptor PPARĪ³ regulates the development of two functionally distinct types of adipose tissue, brown and white fat, as well as the browning of white fat, remains unclear. Our previous studies suggest that PexRAP, a peroxisomal lipid synthetic enzyme, regulates PPARĪ³ signaling and white adipogenesis. Here, we show that PexRAP is an inhibitor of brown adipocyte gene expression. PexRAP inactivation promoted adipocyte browning,Ā increased energy expenditure, and decreased adiposity. Identification of PexRAP-interacting proteins suggests that PexRAP function extends beyond its role as a lipid synthetic enzyme. Notably, PexRAP interacts with importin-Ī²1, a nuclear import factor, and knockdown of PexRAP in adipocytes reduced the levels of nuclear phospholipids. PexRAP also interacts with PPARĪ³, as well as PRDM16, a critical transcriptional regulator of thermogenesis, and disrupts the PRDM16-PPARĪ³ complex, providing a potential mechanism for PexRAP-mediated inhibition of adipocyte browning. These results identify PexRAP as an important regulator of adipose tissue remodeling
Optically Thin Metallic Films for High-radiative-efficiency Plasmonics
Plasmonics enables deep-subwavelength concentration of light and has become
important for fundamental studies as well as real-life applications. Two major
existing platforms of plasmonics are metallic nanoparticles and metallic films.
Metallic nanoparticles allow efficient coupling to far field radiation, yet
their synthesis typically leads to poor material quality. Metallic films offer
substantially higher quality materials, but their coupling to radiation is
typically jeopardized due to the large momentum mismatch with free space. Here,
we propose and theoretically investigate optically thin metallic films as an
ideal platform for high-radiative-efficiency plasmonics. For far-field
scattering, adding a thin high-quality metallic substrate enables a higher
quality factor while maintaining the localization and tunability that the
nanoparticle provides. For near-field spontaneous emission, a thin metallic
substrate, of high quality or not, greatly improves the field overlap between
the emitter environment and propagating surface plasmons, enabling high-Purcell
(total enhancement > ), high-quantum-yield (> 50 %) spontaneous emission,
even as the gap size vanishes (35 nm). The enhancement has almost
spatially independent efficiency and does not suffer from quenching effects
that commonly exist in previous structures.Comment: Supporting Information not included but freely available from
DOI:10.1021/acs.nanolett.6b0085
Inositol phosphorylceramide synthase null Leishmania are viable and virulent in animal infections where salvage of host sphingomyelin predominates
Many pathogens synthesize inositol phosphorylceramide (IPC) as the major sphingolipid (SL), differing from the mammalian host where sphingomyelin (SM) or more complex SLs predominate. The divergence between IPC synthase and mammalian SL synthases has prompted interest as a potential drug target. However, in the trypanosomatid protozoan Leishmania, cultured insect stage promastigotes lack de novo SL synthesis (Īspt
Recommended from our members
Research-based versus clinical serum creatinine measurements and the association of acute kidney injury with subsequent kidney function: findings from the Chronic Renal Insufficiency Cohort study.
Background:Observational studies relying on clinically obtained data have shown that acute kidney injury (AKI) is linked to accelerated chronic kidney disease (CKD) progression. However, prior reports lacked uniform collection of important confounders such as proteinuria and pre-AKI kidney function trajectory, and may be susceptible to ascertainment bias, as patients may be more likely to undergo kidney function testing after AKI. Methods:We studied 444 adults with CKD who participated in the prospective Chronic Renal Insufficiency Cohort (CRIC) Study and were concurrent members of a large integrated healthcare delivery system. We estimated glomerular filtration rate (eGFR) trajectories using serum creatinine measurements from (i) the CRIC research protocol (yearly) and (ii) routine clinical care. We used linear mixed effects models to evaluate the associations of AKI with acute absolute change in eGFR and post-AKI eGFR slope, and explored whether these varied by source of creatinine results. Models were adjusted for demographic characteristics, diabetes status and albuminuria. Results:During median follow-up of 8.5āyears, mean rate of eGFR loss was -0.31āmL/min/1.73 m2/year overall, and 73 individuals experienced AKI (55% Stage 1). A significant interaction existed between AKI and source of serum creatinine for acute absolute change in eGFR level after discharge; in contrast, AKI was independently associated with a faster rate of eGFR decline (mean additional loss of -0.67āmL/min/1.73 m2/year), which was not impacted by source of serum creatinine. Conclusions:AKI is independently associated with subsequent steeper eGFR decline regardless of the serum creatinine source used, but the strength of association is smaller than observed in prior studies after taking into account key confounders such as pre-AKI eGFR slope and albuminuria
Multi-chord fiber-coupled interferometry of supersonic plasma jets and comparisons with synthetic data
A multi-chord fiber-coupled interferometer [Merritt et al., Rev. Sci.
Instrum. 83, 033506 (2012)] is being used to make time-resolved density
measurements of supersonic argon plasma jets on the Plasma Liner Experiment
[Hsu et al., Bull. Amer. Phys. Soc. 56, 307 (2011)]. The long coherence length
of the laser (>10 m) allows signal and reference path lengths to be mismatched
by many meters without signal degradation, making for a greatly simplified
optical layout. Measured interferometry phase shifts are consistent with a
partially ionized plasma in which an initially positive phase shift becomes
negative when the ionization fraction drops below a certain threshold. In this
case, both free electrons and bound electrons in ions and neutral atoms
contribute to the index of refraction. This paper illustrates how the
interferometry data, aided by numerical modeling, are used to derive total jet
density, jet propagation velocity (~15-50 km/s), jet length (~20-100 cm), and
3D expansion.Comment: 6 pages, 4 figures, invited paper at the 19th High Temperature Plasma
Diagnostics Conference, Monterey, CA, May 6--10, 201
Improved genome editing in human cell lines using the CRISPR method
The Cas9/CRISPR system has become a popular choice for genome editing. In this system, binding of a single guide (sg) RNA to a cognate genomic sequence enables the Cas9 nuclease to induce a double-strand break at that locus. This break is next repaired by an error-prone mechanism, leading to mutation and gene disruption. In this study we describe a range of refinements of the method, including stable cell lines expressing Cas9, and a PCR based protocol for the generation of the sgRNA. We also describe a simple methodology that allows both elimination of Cas9 from cells after gene disruption and re-introduction of the disrupted gene. This advance enables easy assessment of the off target effects associated with gene disruption, as well as phenotype-based structure-function analysis. In our study, we used the Fan1 DNA repair gene as control in these experiments. Cas9/CRISPR-mediated Fan1 disruption occurred at frequencies of around 29%, and resulted in the anticipated spectrum of genotoxin hypersensitivity, which was rescued by re-introduction of Fan1
Component analysis of errors in satellite-based precipitation estimates
Satellite-based precipitation estimates have great potential for a wide range of critical applications, but their error characteristics need to be examined and understood. In this study, six (6) high-resolution, satellite-based precipitation data sets are evaluated over the contiguous United States against a gauge-based product. An error decomposition scheme is devised to separate the errors into three independent components, hit bias, missed precipitation, and false precipitation, to better track the error sources associated with the satellite retrieval processes. Our analysis reveals the following. (1) The three components for each product are all substantial, with large spatial and temporal variations. (2) The amplitude of individual components sometimes is larger than that of the total errors. In such cases, the smaller total errors are resulting from the three components canceling one another. (3) All the products detected strong precipitation (\u3e40 mm/d) well, but with various biases. They tend to overestimate in summer and underestimate in winter, by as much as 50% in either season, and they all miss a significant amount of light precipitation (\u3c10 mm/d), up to 40%. (4) Hit bias and missed precipitation are the two leading error sources. In summer, positive hit bias, up to 50%, dominates the total errors for most products. (5) In winter, missed precipitation over mountainous regions and the northeast, presumably snowfall, poses a common challenge to all the data sets. On the basis of the findings, we recommend that future efforts focus on reducing hit bias, adding snowfall retrievals, and improving methods for combining gauge and satellite data. Strategies for future studies to establish better links between the errors in the end products and the upstream data sources are also proposed
Mapping Posttranscriptional Regulation of the Human Glycome Uncovers microRNA Defining the Glycocode
Cell surface glycans form a critical interface with the biological milieu, informing diverse processes from the inflammatory cascade to cellular migration. Assembly of discrete carbohydrate structures requires the coordinated activity of a repertoire of proteins, including glycosyltransferases and glycosidases. Little is known about the regulatory networks controlling this complex biosynthetic process. Recent work points to a role for microRNA (miRNA) in the regulation of specific glycan biosynthetic enzymes. Herein we take a unique systems-based approach to identify connections between miRNA and the glycome. By using our glycomic analysis platform, lectin microarrays, we identify glycosylation signatures in the NCI-60 cell panel that point to the glycome as a direct output of genomic information flow. Integrating our glycomic dataset with miRNA data, we map miRNA regulators onto genes in glycan biosynthetic pathways (glycogenes) that generate the observed glycan structures. We validate three of these predicted miRNA/glycogene regulatory networks: high mannose, fucose, and terminal Ī²-GalNAc, identifying miRNA regulation that would not have been observed by traditional bioinformatic methods. Overall, our work reveals critical nodes in the global glycosylation network accessible to miRNA regulation, providing a bridge between miRNA-mediated control of cell phenotype and the glycome
- ā¦