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Douleurs côté droit sous les côtes : comment les soulager naturellement

En fonction de leurs causes, les douleurs du côté droit peuvent se manifester de différentes manières. Les symptômes de ces douleurs peuvent également varier d’une personne à une autre. Certaines personnes décrivent les douleurs du côté comme des sensations de crampes, de brûlures ou de piqûres. D’autres en revanche parlent de douleurs sourdes ou lancinantes qui irradient […]

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Comment se débarrasser des glaires coincées dans la gorge ?

Gêne constant, difficulté à respirer : avez-vous une impression de glaires coincées dans la gorge actuellement ? Cette impression peut être due à plusieurs facteurs parfois bénignes mais aussi graves. Fort heureusement, il existe quelques astuces naturelles qui vous permettront d’avoir un soulagement en attendant de consulter un médecin ORL. Mais avant, l’impression de glaires coincées dans la gorge est […]

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Quelques remèdes de grand-mère pour soulager les symptômes de la fibromyalgie

En France, environ 2 à 4 % de la population, souvent des femmes, est touchée par la fibromyalgie. Mais en réalité, qu’est-ce que la fibromyalgie ? Quelles sont les astuces naturelles permettant de soulager les patients qui présentent des symptômes de cette maladie ? Quels sont les symptômes de la fibromyalgie ? La fibromyalgie, ou syndrome fibromyalgique, […]

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Quand mettre les professions au féminin dans le domaine de la santé ?

L’utilisation du féminin dans les titres de professions dans le domaine de la santé a beaucoup évolué ces dernières années. Cela reflète une prise de conscience croissante de certaines réalités des métiers de la santé et la reconnaissance de la présence de plus en plus importante des femmes dans le domaine. Vous demandez-vous quand mettre les professions au féminin […]

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Quel est l’IMC normal pour une femme ?

Contrairement à ce qu’on pourrait croire, bien plus de femmes se préoccupent de leurs poids et y font attention. Pour ces femmes, comprendre ce qu’est un indice de masse corporelle (IMC) normal peut permettre de maintenir une bonne santé et savoir quand faire appel à un médecin pour leurs poids. C’est quoi l’IMC ou indice de masse […]

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Quelle est la meilleure recette minceur à base de biscuits aux flocons d’avoine ?

Pour beaucoup de personnes, la perte de poids rime obligatoirement avec une période de privation. Mais contrairement à ces idées reçues, il est bien possible d’observer un régime pour perdre du poids tout en vous faisant plaisir. Découvrez notre recette minceur de biscuits croquants sans beurre aux flocons d’avoine qui raviront vos papilles sans pour autant vous apporter […]

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Quels sont les aliments qui brûlent rapidement les graisses du ventre ?

Le ventre est l’une des parties du corps où il est plus difficile de perdre de la graisse. Souvent, la meilleure solution pour arriver à perdre de la graisse à cet endroit précis du corps consiste à manger sainement et équilibré. Cependant, quels sont les aliments qui brûlent les graisses du ventre sans danger pour la […]

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Croq’Kilos : programme minceur, rééquilibrage alimentaire

Pour de nombreuses personnes, perte de poids rime obligatoirement avec privations. Et si vous appreniez aujourd’hui que vous pouvez perdre efficacement vos kilos en trop sans pour autant vous priver excessivement ? De nombreux programmes minceur et de rééquilibrage, notamment Croq’kilos offrent ce genre d’alternative. Mais de quoi s’agit-il réellement ? C’est quoi Croq’Kilos ? Croq’Kilos […]

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Metabolic profiling in colorectal cancer reveals signature metabolic shifts during tumorigenesis [13. Other]

Colorectal cancer (CRC) arises as the consequence of progressive changes from normal epithelial cells through polyp to tumor, and thus is an useful model for studying metabolic shift. In the present study, we studied the metabolomic profiles using high analyte specific gas chromatography/mass spectrometry (GC/MS) and liquid chromatography tandem mass spectrometry (LC/MS/MS) to attain a systems-level view of the shift in metabolism in cells progressing along the path to CRC. Colonic tissues including tumor, polyps and adjacent matched normal mucosa from 26 patients with sporadic CRC from freshly isolated resections were used for this study. The metabolic profiles were obtained using GC/MS and LC/MS/MS. Our data suggest there was a distinct profile change of a wide range of metabolites from mucosa to tumor tissues. Various amino acids and lipids in the polyps and tumors were elevated, suggesting higher energy needs for increased cellular proliferation. In contrast, significant depletion of glucose and inositol in polyps revealed that glycolysis may be critical in early tumorigenesis. In addition, the accumulation of hypoxanthine and xanthine, and the decrease of uric acid concentration, suggest that the purine biosynthesis pathway could have been substituted by the salvage pathway in CRC. Further, there was a step-wise reduction of deoxycholic acid concentration from mucosa to tumors. It appears that to gain a growth advantage, cancer cells may adopt alternate metabolic pathways in tumorigenesis and this flexibility allows them to adapt and thrive in harsh environment.




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Multiple hypothesis testing in proteomics: A strategy for experimental work [Invited]

In quantitative proteomics work, the differences in expression of many separate proteins are routinely examined to test for significant differences between treatments. This leads to the multiple hypothesis testing problem: when many separate tests are performed many will be significant by chance and be false positive results. Statistical methods such as the false discovery rate (FDR) method that deal with this problem have been disseminated for more than one decade. However a survey of proteomics journals shows that such tests are not widely implemented in one commonly used technique, quantitative proteomics using two-dimensional electrophoresis (2-DE). We outline a selection of multiple hypothesis testing methods, including some that are well known and some lesser known, and present a simple strategy for their use by the experimental scientist in quantitative proteomics work generally. The strategy focuses on the desirability of simultaneous use of several different methods, the choice and emphasis dependent on research priorities and the results in hand. This approach is demonstrated using case scenarios with experimental and simulated model data.




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Oxidative stress-mediated regulation of proteasome complexes [Other]

Oxidative stress has been implicated in aging and many human diseases, notably neurodegenerative disorders and various cancers. The reactive oxygen species that are generated by aerobic metabolism and environmental stressors can chemically modify proteins and alter their biological functions. Cells possess protein repair pathways to rescue oxidized proteins and restore their functions. If these repair processes fail, oxidized proteins may become cytotoxic. Cell homeostasis and viability are therefore dependent on the removal of oxidatively damaged proteins. Numerous studies have demonstrated that the proteasome plays a pivotal role in the selective recognition and degradation of oxidized proteins. Despite extensive research, oxidative stress-triggered regulation of proteasome complexes remains poorly defined. Better understanding of molecular mechanisms underlying proteasome function in response to oxidative stress will provide a basis for developing new strategies aimed at improving cell viability and recovery as well as attenuating oxidation-induced cytotoxicity associated with aging and disease. Here we highlight recent advances in the understanding of proteasome structure and function during oxidative stress and describe how cells cope with oxidative stress through proteasome-dependent degradation pathways.




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The human proteome project: Current state and future direction [Invited]

After successful completion of the Human Genome Project (HGP), HUPO has recently officially launched a global Human Proteome Project (HPP) which is designed to map the entire human protein set. Given the presence of about 30% undisclosed proteins out of 20,300 protein gene products, a systematic global effort is necessary to achieve this goal with respect to protein abundance, distribution, subcellular localization, interaction with other biomolecules, and functions at specific time points. As a general experimental strategy, HPP groups employ the three working pillars for HPP: mass spectrometry, antibody capture, and bioinformatics tools and knowledge base. The HPP participants will take advantage of the output and cross-analyses from the ongoing HUPO initiatives and a chromosome-based protein mapping strategy, termed C-HPP with many national teams currently engaged. In addition, numerous biologically-driven projects will be stimulated and facilitated by the HPP. Timely planning with proper governance of HPP will deliver a protein parts list, reagents and tools for protein studies and analyses, and a stronger basis for personalized medicine. HUPO urges each national research funding agency and the scientific community at large to identify their preferred pathways to participate in aspects of this highly promising project in a HPP consortium of funders and investigators.




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Fourier transform mass spectrometry [Invited]

This article provides an introduction to Fourier transform-based mass spectrometry (FTMS). The key performance characteristics of FTMS, mass accuracy and resolution, are presented in the view of how they impact the interpretation of measurements in proteomic applications. The theory and principles of operation of two types of mass analyzer, Fourier transform ion cyclotron resonance and Orbitrap, are described. Major benefits as well as limitations of FTMS technology are discussed in the context of practical sample analysis, and illustrated with examples included as figures in this text and in the accompanying slide set. Comparisons highlighting the performance differences between the two mass analyzers are made where deemed useful in assisting the user with choosing the most appropriate technology for his/her application. Recent developments of these high-performing mass spectrometers are mentioned to provide a future outlook.




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Principles of electrospray ionization [Biophysical Methods]

Electrospray ionization is today the most widely used ionization technique in chemical and bio-chemical analysis. Interfaced with a mass spectrometer it allows to investigate the molecular composition of liquid samples. With electrospray a large variety of chemical substances can be ionized. There is no limitation in mass which enables even the investigation of large non-covalent protein complexes. Its high ionization efficiency profoundly changed bio-molecular sciences because proteins can be identified and quantified on trace amounts in a high throughput fashion. This review article focusses mainly on the exploration of the underlying ionization mechanism. Some ionization characteristics are discussed which are related to this mechanism. Typical spectra of peptides, proteins and non-covalent complexes are shown and the quantitative character of spectra is highlighted. Finally the possibilities and limitations in measuring the association constant of bivalent non-covalent complexes are described.




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The ProteoRed MIAPE web toolkit: A user-friendly framework to connect and share proteomics standards [Technology]

The development of the HUPO-PSI's (Proteomics Standards Initiative) standard data formats and MIAPE (Minimum Information About a Proteomics Experiment) guidelines should improve proteomics data sharing within the scientific community. Proteomics journals have encouraged the use of these standards and guidelines to improve the quality of experimental reporting and ease the evaluation and publication of manuscripts. However, there is an evident lack of bioinformatics tools specifically designed to create and edit standard file formats and reports, or embed them within proteomics workflows. In this article, we describe a new web-based software suite (The ProteoRed MIAPE web toolkit) that performs several complementary roles related to proteomic data standards. Firstly, it can verify the reports fulfill the minimum information requirements of the corresponding MIAPE modules, highlighting inconsistencies or missing information. Secondly, the toolkit can convert several XML-based data standards directly into human readable MIAPE reports stored within the ProteoRed MIAPE repository. Finally, it can also perform the reverse operation, allowing users to export from MIAPE reports into XML files for computational processing, data sharing or public database submission. The toolkit is thus the first application capable of automatically linking the PSI's MIAPE modules with the corresponding XML data exchange standards, enabling bidirectional conversions. This toolkit is freely available at http://www.proteored.org/MIAPE/.




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Bayesian Proteoform Modeling Improves Protein Quantification of Global Proteomic Measurements [Technology]

As the capability of mass spectrometry-based proteomics has matured, tens of thousands of peptides can be measured simultaneously, which has the benefit of offering a systems view of protein expression. However, a major challenge is that with an increase in throughput, protein quantification estimation from the native measured peptides has become a computational task. A limitation to existing computationally-driven protein quantification methods is that most ignore protein variation, such as alternate splicing of the RNA transcript and post-translational modifications or other possible proteoforms, which will affect a significant fraction of the proteome. The consequence of this assumption is that statistical inference at the protein level, and consequently downstream analyses, such as network and pathway modeling, have only limited power for biomarker discovery. Here, we describe a Bayesian model (BP-Quant) that uses statistically derived peptides signatures to identify peptides that are outside the dominant pattern, or the existence of multiple over-expressed patterns to improve relative protein abundance estimates. It is a research-driven approach that utilizes the objectives of the experiment, defined in the context of a standard statistical hypothesis, to identify a set of peptides exhibiting similar statistical behavior relating to a protein. This approach infers that changes in relative protein abundance can be used as a surrogate for changes in function, without necessarily taking into account the effect of differential post-translational modifications, processing, or splicing in altering protein function. We verify the approach using a dilution study from mouse plasma samples and demonstrate that BP-Quant achieves similar accuracy as the current state-of-the-art methods at proteoform identification with significantly better specificity. BP-Quant is available as a MatLab ® and R packages at https://github.com/PNNL-Comp-Mass-Spec/BP-Quant.




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WITHDRAWN: Quantitative mass spectrometry analysis of PD-L1 protein expression, N-glycosylation and expression stoichiometry with PD-1 and PD-L2 in human melanoma [Research]

This article has been withdrawn by the authors. We discovered an error after this manuscript was published as a Paper in Press. Specifically, we learned that the structures of glycans presented for the PD-L1 peptide were drawn and labeled incorrectly. We wish to withdraw this article and submit a corrected version for review.




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Translating Divergent Environmental Stresses into a Common Proteome Response through Hik33 in a Model Cyanobacterium [Research]

The histidine kinase Hik33 plays important roles in mediating cyanobacterial response to divergent types of abiotic stresses including cold, salt, high light (HL), and osmotic stresses. However, how these functions are regulated by Hik33 remains to be addressed. Using a hik33-deficient strain (hik33) of Synechocystis sp. PCC 6803 (Synechocystis) and quantitative proteomics, we found that Hik33 depletion induces differential protein expression highly similar to that induced by divergent types of stresses. This typically includes downregulation of proteins in photosynthesis and carbon assimilation that are necessary for cell propagation, and upregulation of heat shock proteins, chaperons, and proteases that are important for cell survival. This observation indicates that depletion of Hik33 alone mimics divergent types of abiotic stresses, and that Hik33 could be important for preventing abnormal stress response in the normal condition. Moreover, we found the majority of proteins of plasmid origin were significantly upregulated in hik33, though their biological significance remains to be addressed. Together, the systematically characterized Hik33-regulated cyanobacterial proteome, which is largely involved in stress responses, builds the molecular basis for Hik33 as a general regulator of stress responses.




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Meta-heterogeneity: evaluating and describing the diversity in glycosylation between sites on the same glycoprotein [Review]

Mass spectrometry-based glycoproteomics has gone through some incredible developments over the last few years. Technological advances in glycopeptide enrichment, fragmentation methods, and data analysis workflows have enabled the transition of glycoproteomics from a niche application, mainly focused on the characterization of isolated glycoproteins, to a mature technology capable of profiling thousands of intact glycopeptides at once. In addition to numerous biological discoveries catalyzed by the technology, we are also observing an increase in studies focusing on global protein glycosylation and the relationship between multiple glycosylation sites on the same protein. It has become apparent that just describing protein glycosylation in terms of micro- and macro-heterogeneity, respectively the variation and occupancy of glycans at a given site, is not sufficient to describe the observed interactions between sites. In this perspective we propose a new term, meta-heterogeneity, to describe a higher level of glycan regulation: the variation in glycosylation across multiple sites of a given protein. We provide literature examples of extensive meta-heterogeneity on relevant proteins such as antibodies, erythropoietin, myeloperoxidase and a number of serum and plasma proteins. Furthermore, we postulate on the possible biological reasons and causes behind the intriguing meta-heterogeneity observed in glycoproteins.




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Calculating glycoprotein similarities from mass spectrometric data [Review]

Complex protein glycosylation occurs through biosynthetic steps in the secretory pathway that create macro- and microheterogeneity of structure and function.  Required for all life forms, glycosylation diversifies and adapts protein interactions with binding partners that underpin interactions at cell surfaces and pericellular and extracellular environments. Because these biological effects arise from heterogeneity of structure and function, it is necessary to measure their changes as part of the quest to understand nature.  Quite often, however, the assumption behind proteomics that post-translational modifications are discrete additions that can be modeled using the genome as a template does not apply to protein glycosylation.  Rather, it is necessary to quantify the glycosylation distribution at each glycosite and to aggregate this information into a population of mature glycoproteins that exist in a given biological system.  To date, mass spectrometric methods for assigning singly glycosylated peptides are well-established.  But it is necessary to quantify glycosylation heterogeneity accurately in order to gauge the alterations that occur during biological processes.  The task is to quantify the glycosylated peptide forms as accurately as possible and then apply appropriate bioinformatics algorithms to the calculation of micro- and macro-similarities.  In this review, we summarize current approaches for protein quantification as they apply to this glycoprotein similarity problem.




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Developments in Mass Spectrometry for Glycosaminoglycan Analysis: A Review [Review]

This review covers recent developments in glycosaminoglycan (GAG) analysis via mass spectrometry (MS). GAGs participate in a variety of biological functions, including cellular communication, wound healing, and anticoagulation, and are important targets for structural characterization. GAGs exhibit a diverse range of structural features due to the variety of O- and N-sulfation modifications and uronic acid C-5 epimerization that can occur, making their analysis a challenging target. Mass spectrometry approaches to the structure assignment of GAGs have been widely investigated, and new methodologies remain the subject of development. Advances in sample preparation, tandem MS techniques (MS/MS), on-line separations and automated analysis software have advanced the field of GAG analysis. These recent developments have led to remarkable improvements in the precision and time efficiency for the structural characterization of GAGs.




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Methods for Enrichment and Assignment of N-Acetylglucosamine Modification Sites [Review]

O-GlcNAcylation, the addition of a single N-acetylglucosamine residue to serine and threonine residues of cytoplasmic, nuclear, or mitochondrial proteins, is a widespread regulatory post-translational modification. It is involved in response to nutritional status and stress and its dysregulation is associated with diseases ranging from Alzheimer’s to diabetes.  While the modification was first detected over thirty-five years ago, research into the function of O-GlcNAcylation has accelerated dramatically in the last ten years due to the development of new enrichment and mass spectrometry techniques that facilitate its analysis.  This article summarizes methods for O-GlcNAc enrichment, key mass spectrometry instrumentation advancements, particularly those that allow modification site localization, and software tools that allow analysis of data from O-GlcNAc modified peptides.




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A Pragmatic Guide to Enrichment Strategies for Mass Spectrometry-based Glycoproteomics [Review]

Glycosylation is a prevalent, yet heterogeneous modification with a broad range of implications in molecular biology. This heterogeneity precludes enrichment strategies that can be universally beneficial for all glycan classes. Thus, choice of enrichment strategy has profound implications on experimental outcomes. Here we review common enrichment strategies used in modern mass spectrometry (MS)-based glycoproteomic experiments, including lectins and other affinity chromatographies, hydrophilic interaction chromatography (HILIC) and its derivatives, porous graphitic carbon (PGC), reversible and irreversible chemical coupling strategies, and chemical biology tools that often leverage bioorthogonal handles. Interest in glycoproteomics continues to surge as MS instrumentation and software improve, so this review aims to help equip researchers with necessary information to choose appropriate enrichment strategies that best complement these efforts.




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Integrated glycoproteomics identifies a role of N-glycosylation and galectin-1 on myogenesis and muscle development [Research]

Many cell surface and secreted proteins are modified by the covalent addition of glycans that play an important role in the development of multicellular organisms. These glycan modifications enable communication between cells and the extracellular matrix via interactions with specific glycan-binding lectins and the regulation of receptor-mediated signaling. Aberrant protein glycosylation has been associated with the development of several muscular diseases suggesting essential glycan- and lectin-mediated functions in myogenesis and muscle development but our molecular understanding of the precise glycans, catalytic enzymes and lectins involved remain only partially understood. Here, we quantified dynamic remodeling of the membrane-associated proteome during a time-course of myogenesis in cell culture. We observed wide-spread changes in the abundance of several important lectins and enzymes facilitating glycan biosynthesis. Glycomics-based quantification of released N-linked glycans confirmed remodeling of the glycome consistent with the regulation of glycosyltransferases and glycosidases responsible for their formation including a previously unknown di-galactose-to-sialic acid switch supporting a functional role of these glycoepitopes in myogenesis. Furthermore, dynamic quantitative glycoproteomic analysis with multiplexed stable isotope labelling and analysis of enriched glycopeptides with multiple fragmentation approaches identified glycoproteins modified by these regulated glycans including several integrins and growth factor receptors. Myogenesis was also associated with the regulation of several lectins most notably the up-regulation of galectin-1 (LGALS1). CRISPR/Cas9-mediated deletion of Lgals1 inhibited differentiation and myotube formation suggesting an early functional role of galectin-1 in the myogenic program. Importantly, similar changes in N-glycosylation and the up-regulation of galectin-1 during postnatal skeletal muscle development were observed in mice. Treatment of new-born mice with recombinant adeno-associated viruses to overexpress galectin-1 in the musculature resulted in enhanced muscle mass. Our data form a valuable resource to further understand the glycobiology of myogenesis and will aid the development of intervention strategies to promote healthy muscle development or regeneration.




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Systematic Proteome and Lysine Succinylome Analysis Reveals the Enhanced Cell Migration by Hyposuccinylation in Esophageal Squamous Cell Cancer [Research]

Esophageal squamous cell cancer (ESCC) is an aggressive malignancy with poor therapeutic outcomes. However, the alterations in proteins and post-translational modifications (PTMs) leading to the pathogenesis of ESCC remains unclear. Here, we provide the comprehensive characterization of the proteome, phosphorylome, lysine acetylome and succinylome for ESCC and matched control cells using quantitative proteomic approach. We identify abnormal protein and post-translational modification (PTM) pathways, including significantly downregulated lysine succinylation sites in cancer cells. Focusing on hyposuccinylation, we reveal that this altered PTM was enriched on enzymes of metabolic pathways inextricably linked with cancer metabolism. Importantly, ESCC malignant behaviors such as cell migration are inhibited once the level of succinylation was restored in vitro or in vivo. This effect was further verified by mutations to disrupt succinylation sites in candidate proteins. Meanwhile, we found that succinylation has a negative regulatory effect on histone methylation to promote cancer migration. Finally, hyposuccinylation is confirmed in primary ESCC specimens. Our findings together demonstrate that lysine succinylation may alter ESCC metabolism and migration, providing new insights into the functional significance of PTM in cancer biology.




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N-glycomic signature of stage II colorectal cancer and its association with the tumor microenvironment [Research]

The choice for adjuvant chemotherapy in stage II colorectal cancer (CRC) is controversial as many patients are cured by surgery alone and it is difficult to identify patients with high-risk of recurrence of the disease. There is a need for better stratification of this group of patients. Mass spectrometry imaging could identify patients at risk. We report here the N-glycosylation signatures of the different cell populations in a group of stage II CRC tissue samples. The cancer cells, compared to normal epithelial cells, have increased levels of sialylation and high-mannose glycans, as well as decreased levels of fucosylation and highly branched N-glycans. When looking at the interface between cancer and its microenvironment, it seems that the cancer N-glycosylation signature spreads into the surrounding stroma at the invasive front of the tumor. This finding was more outspoken in patients with a worse outcome within this sample group.




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Transcriptome and secretome analysis of intra-mammalian life-stages of the emerging helminth pathogen, Calicophoron daubneyi reveals adaptation to a unique host environment. [Research]

Paramphistomosis, caused by the rumen fluke, Calicophoron daubneyi, is a parasitic infection of ruminant livestock which has seen a rapid rise in prevalence throughout Western Europe in recent years. Following ingestion of metacercariae (parasite cysts) by the mammalian host, newly-excysted juveniles (NEJs) emerge and invade the duodenal submucosa which causes significant pathology in heavy infections. The immature larvae then migrate upwards, along the gastrointestinal tract, and enter the rumen where they mature and begin to produce eggs. Despite their emergence, and sporadic outbreaks of acute disease, we know little about the molecular mechanisms used by C. daubneyi to establish infection, acquire nutrients and to avoid the host immune response. Here, transcriptome analysis of four intra-mammalian life-cycle stages, integrated with secretome analysis of the NEJ and adult parasites (responsible for acute and chronic disease respectively), revealed how the expression and secretion of selected families of virulence factors and immunomodulators are regulated in accordance with fluke development and migration. Our data show that whilst a family of cathepsins B with varying S2 sub-site residues (indicating distinct substrate specificities) are differentially secreted by NEJs and adult flukes, cathepsins L and F are secreted in low abundance by NEJs only. We found that C. daubneyi has an expanded family of aspartic peptidases, which is up-regulated in adult worms, although they are underrepresented in the secretome. The most abundant proteins in adult fluke secretions were helminth defence molecules (HDMs) that likely establish an immune environment permissive to fluke survival and/or neutralise pathogen-associated molecular patterns (PAMPs) such as bacterial lipopolysaccharide in the microbiome-rich rumen. The distinct collection of molecules secreted by C. daubneyi allowed the development of the first coproantigen-based ELISA for paramphistomosis which, importantly, did not recognise antigens from other helminths commonly found as co-infections with rumen fluke.




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Thermal proteome profiling in zebrafish reveals effects of napabucasin on retinoic acid metabolism [Research]

Thermal proteome profiling (TPP) allows for the unbiased detection of drug – target protein engagements in vivo. Traditionally, one cell type is used for TPP studies, with the risk of missing important differentially expressed target proteins. The use of whole organisms would circumvent this problem. Zebrafish embryos are amenable to such an approach. Here, we used TPP on whole zebrafish embryo lysate to identify protein targets of napabucasin, a compound that may affect Signal transducer and activator of transcription 3 (Stat3) signaling through an ill-understood mechanism. In zebrafish embryos, napabucasin induced developmental defects consistent with inhibition of Stat3 signaling. TPP profiling showed no distinct shift in Stat3 upon napabucasin treatment, but effects were detected on the oxidoreductase, Pora, which might explain effects on Stat3 signaling. Interestingly, thermal stability of several aldehyde dehydrogenases (Aldhs) was affected. Moreover, napabucasin activated ALDH enzymatic activity in vitro. Aldhs have crucial roles in retinoic acid metabolism and functionally we validated napabucasin-mediated activation of the retinoic acid pathway in zebrafish in vivo. We conclude that TPP profiling in whole zebrafish embryo lysate is feasible and facilitates direct correlation of in vivo effects of small molecule drugs with their protein targets.




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Blockade of High-Fat Diet Proteomic Phenotypes using Exercise as Prevention or Treatment [Technological Innovation and Resources]

The increasing consumption of high-fat foods combined with a lack of exercise is a major contributor to the burden of obesity in humans. Aerobic exercise such as running is known to provide metabolic benefits, but how the over-consumption of a high fat diet (HFD) and exercise interact is not well characterized at the molecular level. Here, we examined the plasma proteome in mice for the effects of aerobic exercise as both a treatment and as a preventative regime for animals on either HFD or a healthy control diet. This analysis detected large changes in the plasma proteome induced by the HFD, such as increased abundance of SERPINA7, ALDOB, and down-regulation of SERPINA1E, CFD (adipsin). Some of these changes were significantly reverted using exercise as a preventative measure, but not as a treatment regime. To determine if either the intensity, or duration, of exercise influenced the outcome, we compared high-intensity interval training (HIIT) and endurance running. Endurance running slightly out-performed HIIT exercise, but overall, both provided similar reversion in abundance of plasma proteins modulated by the high-fat diet including SERPINA7, APOE, SERPINA1E, and CFD. Finally, we compared the changes induced by over-consumption of HFD to previous data from mice fed an isocaloric high saturated fat (SFA) or polyunsaturated fat (PUFA) diet. This identified several common changes including increased APOC2 and APOE, but also highlighted changes specific for either over-consumption of HFD (ALDOB, SERPINA7, CFD), SFA-based diets (SERPINA1E), or PUFA-based diets (Haptoglobin - Hp). Together, these data highlight the importance of early intervention with exercise to revert HFD-induced phenotypes and suggest some of the molecular mechanisms leading to the changes in the plasma proteome generated by high fat diet consumption. Web-based interactive visualizations are provided for this dataset (larancelab.com/hfd-exercise), which give insight into diet and exercise phenotypic interactions on the plasma proteome.




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The complexity and dynamics of the tissue glycoproteome associated with prostate cancer progression [Research]

The complexity and dynamics of the immensely heterogeneous glycoproteome of the prostate cancer (PCa) tumour micro-environment remain incompletely mapped, a knowledge gap that impedes our molecular-level understanding of the disease. To this end, we have used sensitive glycomics and glycoproteomics to map the protein-, cell- and tumour grade-specific N- and O-glycosylation in surgically-removed PCa tissues spanning five histological grades (n = 10/grade) and tissues from patients with benign prostatic hyperplasia (n = 5). Quantitative glycomics revealed PCa grade-specific alterations of the oligomannosidic-, paucimannosidic- and branched sialylated complex-type N-glycans, and dynamic remodelling of the sialylated core 1- and core 2-type O-glycome. Deep quantitative glycoproteomics identified ~7,400 unique N-glycopeptides from 500 N-glycoproteins and ~500 unique O-glycopeptides from nearly 200 O-glycoproteins. With reference to a recent Tissue and Blood Atlas, our data indicate that paucimannosidic glycans of the PCa tissues arise mainly from immune cell-derived glycoproteins. Further, the grade-specific PCa glycosylation arises primarily from dynamics in the cellular makeup of the PCa tumour microenvironment across grades involving increased oligomannosylation of prostate-derived glycoproteins and decreased bisecting GlcNAcylation of N-glycans carried by the extracellular matrix proteins. Further, elevated expression of several oligosaccharyltransferase subunits and enhanced N-glycoprotein site occupancy were observed associated with PCa progression. Finally, correlations between the protein-specific glycosylation and PCa progression were observed including increased site-specific core 2-type O-glycosylation of collagen VI. In conclusion, integrated glycomics and glycoproteomics have enabled new insight into the complexity and dynamics of the tissue glycoproteome associated with PCa progression generating an important resource to explore the underpinning disease mechanisms.




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Accelerating the field of epigenetic histone modification through mass spectrometry-based approaches [Review]

Histone post-translational modifications (PTMs) are one of the main mechanisms of epigenetic regulation. Dysregulation of histone PTMs leads to many human diseases, such as cancer. Due to its high-throughput, accuracy, and flexibility, mass spectrometry (MS) has emerged as a powerful tool in the epigenetic histone modification field, allowing the comprehensive and unbiased analysis of histone PTMs and chromatin-associated factors. Coupled with various techniques from molecular biology, biochemistry, chemical biology and biophysics, MS has been employed to characterize distinct aspects of histone PTMs in the epigenetic regulation of chromatin functions. In this review we will describe advancements in the field of MS that have facilitated the analysis of histone PTMs and chromatin biology.  




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Quantitative proteomics reveal neuron projection development genes ARF4, KIF5B and RAB8A associated with Hirschsprung disease [Research]

Hirschsprung disease (HSCR) is a heterogeneous group of neurocristopathy characterized by the absence of the enteric ganglia along a variable length of the intestine. Genetic defects play a major role in the pathogenesis of HSCR while family studies of pathogenic variants in all the known genes (loci) only demonstrate incomplete penetrance and variable expressivity for unknown reasons. Here, we applied large-scale, quantitative proteomics of human colon tissues from 21 patients using iTRAQ method followed by bioinformatics analysis. Selected findings were confirmed by parallel reaction monitoring (PRM) verification. At last the interesting differentially expressed proteins were confirmed by western blot. A total of 5341 proteins in human colon tissues were identified. Among them, 664 proteins with >1.2-fold difference were identified in 6 groups: groups A1 and A2 pooled protein from the ganglionic and aganglionic colon of male, long-segment HSCR patients (L-HSCR, n=7); groups B1 and B2 pooled protein from the ganglionic and aganglionic colon of male, short-segment HSCR patients (S-HSCR, n=7); and groups C1 and C2 pooled protein from the ganglionic and aganglionic colon of female, S-HSCR patients (n=7). Based on these analyses, 49 proteins from 5 pathways were selected for PRM verification, including ribosome, endocytosis, spliceosome, oxidative phosphorylation and cell adhesion. The downregulation of three neuron projection development genes ARF4, KIF5B and RAB8A in the aganglionic part of the colon were verified in 15 paired colon samples using WB. The findings of this study will shed new light on the pathogenesis of HSCR and facilitate the development of therapeutic targets.




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Thyroglobulin interactome profiling defines altered proteostasis topology associated with thyroid dyshormonogenesis [Research]

Thyroglobulin (Tg) is a secreted iodoglycoprotein serving as the precursor for T3 and T4 hormones. Many characterized Tg gene mutations produce secretion-defective variants resulting in congenital hypothyroidism (CH). Tg processing and secretion is controlled by extensive interactions with chaperone, trafficking, and degradation factors comprising the secretory proteostasis network. While dependencies on individual proteostasis network components are known, the integration of proteostasis pathways mediating Tg protein quality control and the molecular basis of mutant Tg misprocessing remain poorly understood. We employ a multiplexed quantitative affinity purification–mass spectrometry approach to define the Tg proteostasis interactome and changes between WT and several CH-variants. Mutant Tg processing is associated with common imbalances in proteostasis engagement including increased chaperoning, oxidative folding, and engagement by targeting factors for ER-associated degradation (ERAD). Furthermore, we reveal mutation-specific changes in engagement with N-glycosylation components, suggesting distinct requirements for one Tg variant on dual engagement of both oligosaccharyltransferase complex isoforms for degradation. Modulating dysregulated proteostasis components and pathways may serve as a therapeutic strategy to restore Tg secretion and thyroid hormone biosynthesis.




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Proteome analysis reveals a significant host-specific response in Rhizobium leguminosarum bv viciae endosymbiotic cells [Research]

The Rhizobium-legume symbiosis is a beneficial interaction in which the bacterium converts atmospheric nitrogen into ammonia and delivers it to the plant in exchange for carbon compounds. This symbiosis implies the adaptation of bacteria to live inside host plant cells. In this work we apply RP-LC-MS/MS and  iTRAQ techniques to study the proteomic profile of endosymbiotic cells (bacteroids) induced by Rhizobium leguminosarum bv viciae strain UPM791 in legume nodules. Nitrogenase subunits, tricarboxylic acid cycle enzymes, and stress response proteins are amongst the most abundant from over one thousand rhizobial proteins identified in pea (Pisum sativum) bacteroids. Comparative analysis of bacteroids induced in pea and in lentil (Lens culinaris)nodules revealed the existence of a significant host-specific differential response affecting dozens of bacterial proteins, including stress-related proteins, transcriptional regulators, and proteins involved in the carbon and nitrogen metabolisms. A mutant affected in one of these proteins, homologous to a GntR-like transcriptional regulator, showed a symbiotic performance significantly  impaired in symbiosis with pea, but not with lentil plants. Analysis of the proteomes of bacteroids isolated from both hosts also revealed the presence of different sets of plant-derived nodule-specific cysteine rich (NCR) peptides, indicating that the endosymbiotic bacteria find a host-specific cocktail of chemical stressors inside the nodule. By studying variations of the bacterial response to different plant cell environments we will be able to identify specific limitations imposed by the host that might give us clues for the improvement of rhizobial performance.




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Imaging Mass Spectrometry and Lectin Analysis of N-linked Glycans in Carbohydrate Antigen Defined Pancreatic Cancer Tissues [Research]

The early detection of pancreatic ductal adenocarcinoma is a complex clinical obstacle yet is key to improving the overall likelihood of patient survival. Current and prospective carbohydrate biomarkers CA19-9 and sTRA are sufficient for surveilling disease progression yet are not approved for delineating PDAC from other abdominal cancers and non-cancerous pancreatic pathologies. To further understand these glycan epitopes, an imaging mass spectrometry approach was utilized to assess the N-glycome of the human pancreas and pancreatic cancer in a cohort of PDAC patients represented by tissue microarrays and whole tissue sections. Orthogonally, these same tissues were characterized by multi-round immunofluorescence which defined expression of CA19-9 and sTRA as well as other lectins towards carbohydrate epitopes with the potential to improve PDAC diagnosis. These analyses revealed distinct differences not only in N-glycan spatial localization across both healthy and diseased tissues but importantly between different biomarker-categorized tissue samples. Unique sulfated bi-antennary N-glycans were detected specifically in normal pancreatic islets. N-glycans from CA19-9 expressing tissues tended to be bi-, tri- and tetra-antennary structures with both core and terminal fucose residues and bisecting N-acetylglucosamines. These N-glycans were detected in less abundance in sTRA-expressing tumor tissues, which favored tri- and tetra-antennary structures with polylactosamine extensions. Increased sialylation of N-glycans was detected in all tumor tissues. A candidate new biomarker derived from IMS was further explored by fluorescence staining with selected lectins on the same tissues. The lectins confirmed the expression of the epitopes in cancer cells and revealed different tumor-associated staining patterns between glycans with bisecting GlcNAc and those with terminal GlcNAc. Thus, the combination of lectin-IHC and IMS techniques produces more complete information for tumor classification than the individual analyses alone. These findings potentiate the development of early assessment technologies to rapidly and specifically identify PDAC in the clinic that may directly impact patient outcomes.




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Proteome Turnover in the Spotlight: Approaches, Applications & Perspectives [Review]

In all cells, proteins are continuously synthesized and degraded in order to maintain protein homeostasis and modify gene expression levels in response to stimuli. Collectively, the processes of protein synthesis and degradation are referred to as protein turnover. At steady state, protein turnover is constant to maintain protein homeostasis, but in dynamic responses, proteins change their rates of synthesis and degradation in order to adjust their proteomes to internal or external stimuli. Thus, probing the kinetics and dynamics of protein turnover lends insight into how cells regulate essential processes such as growth, differentiation, and stress response. Here we outline historical and current approaches to measuring the kinetics of protein turnover on a proteome-wide scale in both steady-state and dynamic systems, with an emphasis on metabolic tracing using stable-isotope-labeled amino acids. We highlight important considerations for designing proteome turnover experiments, key biological findings regarding the conserved principles of proteome turnover regulation, and future perspectives for both technological and biological investigation.




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Prediction and validation of mouse meiosis-essential genes based on spermatogenesis proteome dynamics [Research]

The molecular mechanism associated with mammalian meiosis has yet to be fully explored, and one of the main reasons for this lack of exploration is that some meiosis-essential genes are still unknown. The profiling of gene expression during spermatogenesis has been performed in previous studies, yet few studies have aimed to find new functional genes. Since there is a huge gap between the number of genes that are able to be quantified and the number of genes that can be characterized by phenotype screening in one assay, an efficient method to rank quantified genes according to phenotypic relevance is of great importance. We proposed to rank genes by the probability of their function in mammalian meiosis based on global protein abundance using machine learning. Here, nine types of germ cells focusing on continual substages of meiosis prophase I were isolated, and the corresponding proteomes were quantified by high-resolution mass spectrometry. By combining meiotic labels annotated from the MGI mouse knockout database and the spermatogenesis proteomics dataset, a supervised machine learning package, FuncProFinder, was developed to rank meiosis-essential candidates. Of the candidates whose functions were unannotated, four of ten genes with the top prediction scores, Zcwpw1, Tesmin, 1700102P08Rik and Kctd19, were validated as meiosis-essential genes by knockout mouse models. Therefore,  mammalian meiosis-essential genes could be efficiently predicted based on the protein abundance dataset, which provides a paradigm for other functional gene mining from a related abundance dataset.




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The Mechanism of NEDD8 Activation of CUL5 Ubiquitin E3 Ligases [Research]

Cullin RING E3 Ligases (CRLs) ubiquitylate hundreds of important cellular substrates. Here we have assembled and purified the Ankyrin repeat and SOCS Box protein 9 CUL5 RBX2 Ligase (ASB9-CRL) in vitro and show how it ubiquitylates one of its substrates, CKB. CRLs occasionally collaborate with RING between RING E3 ligases (RBRLs) and indeed, mass spectrometry analysis showed that CKB is specifically ubiquitylated by the ASB9-CRL-ARIH2-UBE2L3 complex. Addition of other E2s such as UBE2R1 or UBE2D2 contribute to polyubiquitylation but do not alter the sites of CKB ubiquitylation. Hydrogen-deuterium exchange mass spectrometry (HDX-MS) analysis revealed that CUL5 neddylation allosterically exposes its ARIH2 binding site, promoting high affinity binding, and it also sequesters the NEDD8 E2 (UBE2F) binding site on RBX2. Once bound, ARIH2 helices near the Ariadne domain active site are exposed, presumably relieving its autoinhibition. These results allow us to propose a model of how neddylation activates ASB-CRLs to ubiquitylate their substrates.




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A proteomics-based assessment of inflammation signatures in endotoxemia [Research]

We have previously shown that multimers of plasma pentraxin-3 (PTX3) were predictive of survival in patients with sepsis. To characterize the release kinetics and cellular source of plasma protein changes in sepsis, serial samples were obtained from healthy volunteers (n=10, 3 time-points) injected with low-dose endotoxin (LPS) and analyzed using data-independent acquisition (DIA) MS. The human plasma proteome response was compared to an LPS-induced endotoxemia model in mice. Proteomic analysis of human plasma revealed a rapid neutrophil degranulation signature, followed by a rise in acute phase proteins. Changes in circulating PTX3 correlated with increases in neutrophil-derived proteins following LPS injection. Time course analysis of the plasma proteome in mice showed a time-dependent increase in multimeric PTX3, alongside increases in neutrophil-derived myeloperoxidase (MPO) upon LPS treatment. The mechanisms of oxidation-induced multimerisation of PTX3 were explored in two genetic mouse models: MPO global knock-out mice and LysM CreNox2KO mice, in which NADPH oxidase 2 (Nox2) is only deficient in myeloid cells. Nox2 is the enzyme responsible for the oxidative burst in neutrophils. Increases in plasma multimeric PTX3 were not significantly different between wildtype and MPO or LysM CreNox2KO knock-out mice. Thus, PTX3 may already be stored and released in a multimeric form. Through in vivo neutrophil depletion and multiplexed vascular proteomics, PTX3 multimer deposition within the aorta was confirmed to be neutrophil-dependent. Proteomic analysis of aortas from LPS-injected mice returned PTX3 as the most upregulated protein, where multimeric PTX3 was deposited as early as 2 h post-LPS along with other neutrophil-derived proteins. In conclusion, the rise in multimeric PTX3 upon LPS injection correlates with neutrophil-related protein changes in plasma and in aortas. MPO and myeloid Nox2 are not required for the multimerisation of PTX3; instead, neutrophil extravasation is responsible for the LPS-induced deposition of multimeric PTX3 in the aorta.




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A potential role for the Gsdf-eEF1{alpha} complex in inhibiting germ cell proliferation: A protein-interaction analysis in medaka (Oryzias latipes) from a proteomics perspective [Research]

Gonadal soma-derived factor (gsdf) has been demonstrated to be essential for testicular differentiation in medaka (Oryzias latipes). To understand the protein dynamics of Gsdf in spermatogenesis regulation, we used a His-tag "pull-down" assay coupled with shotgun LC-MS/MS to identify a group of potential interacting partners for Gsdf, which included cytoplasmic dynein light chain 2, eukaryotic polypeptide elongation factor 1 alpha (eEF1α), and actin filaments in mature medaka testis. As for the interaction with TGFβ-dynein being critical for spermatogonial division in Drosophila melanogaster, the physical interactions of Gsdf-dynein and Gsdf-eEF1α were identified through a yeast 2-hybrid (Y2H) screening of an adult testis cDNA library using Gsdf as bait, which were verified by a paired Y2H assay. Co-immunoprecipitation of Gsdf and eEF1α was defined in adult testes as supporting the requirement of a Gsdf and eEF1α interaction in testis development. Proteomics analysis (data are available via ProteomeXchange with identifier PXD022153) and ultrastrutural observations showed that Gsdf deficiency activated eEF1α-mediated protein synthesis and ribosomal biogenesis, which in turn led to the differentiation of undifferentiated germ cells. Thus, our results provide a framework and new insight into the coordination of a Gsdf (TGFβ and eEF1α complex in the basic processes of germ cell proliferation, transcriptional and translational control of sexual RNA which may be fundamentally conserved across phyla during sexual differentiation.




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In depth characterization of the Staphylococcus aureus phosphoproteome reveals new targets of Stk1 [Research]

Staphylococcus aureus is a major cause of infections worldwide and infection results in a variety of diseases. As of no surprise, protein phosphorylation is an important game player in signaling cascades and has been shown to be involved in S. aureus virulence. Albeit long neglected, eukaryotic-type serine/threonine kinases in S. aureus have been implicated in this complex signaling cascades. Due to the sub-stoichiometric nature of protein phosphorylation and a lack of suitable analysis tools, the knowledge of these cascades is however, to date, still limited.

Here, were apply an optimized protocol for efficient phosphopeptide enrichment via Fe3+-IMAC followed by LC-MS/MS to get a better understanding of the impact of protein phosphorylation on the complex signaling networks involved in pathogenicity. By profiling a serine/threonine kinase and phosphatase mutant from a methicillin-resistant S. aureus mutant library, we generated the most comprehensive phosphoproteome dataset of S. aureus to date, aiding a better understanding of signaling in bacteria. With the identification of 3800 class I p-sites we were able to increase the number of identifications by more than 21 times compared to recent literature. In addition, we were able to identify 74 downstream targets of the only reported eukaryotic-type Ser/Thr kinase of the S. aureus strain USA300, Stk1. This work allowed an extensive analysis of the bacterial phosphoproteome and indicates that Ser/Thr kinase signaling is far more abundant than previously anticipated in S. aureus.




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Multi-sample mass spectrometry-based approach for discovering injury markers in chronic kidney disease [Research]

Urinary proteomics studies have primarily focused on identifying markers of chronic kidney disease (CKD) progression. Here, we aimed to determine urinary markers of CKD renal parenchymal injury through proteomics analysis in animal kidney tissues and cells and in the urine of patients with CKD. Label-free quantitative proteomics analysis based on liquid chromatography-tandem mass spectrometry was performed on urine samples obtained from 6 normal controls and 9, 11, and 10 patients with CKD stages 1, 3, and 5, respectively, and on kidney tissue samples from a rat CKD model by 5/6 nephrectomy. Tandem mass tag-based quantitative proteomics analysis was performed for primary cultured glomerular endothelial cells (GECs) and proximal tubular epithelial cells (PTECs) before and after inducing 24-h hypoxia injury. Upon hierarchical clustering, out of 858 differentially expressed proteins (DEPs) in the urine of CKD patients, the levels of 416 decreased and 403 increased sequentially according to the disease stage, respectively. Among 2965 DEPs across 5/6 nephrectomized and sham-operated rat kidney tissues, 86 DEPs showed same expression patterns in the urine and kidney tissue. After cross-validation with two external animal proteome datasets, 38 DEPs were organized; only 10 DEPs, including serotransferrin, gelsolin, poly ADP-ribose polymerase 1, neuroblast differentiation-associated protein AHNAK, microtubule-associated protein 4, galectin-1, protein S, thymosin beta-4, myristoylated alanine-rich C-kinase substrate, and vimentin were finalized by screening human GECs and PTECs data. Among these ten potential candidates for universal CKD marker, validation analyses for protein S and galectin-1 were conducted. Galectin-1 was observed to have a significant inverse correlation with renal function as well as higher expression in glomerulus with chronic injury than protein S. This constitutes the first multi-sample proteomics study for identifying key renal-expressed proteins associated with CKD progression. The discovered proteins represent potential markers of chronic renal cell and tissue damage and candidate contributors to CKD pathophysiology.




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Systematic identification of P. falciparum sporozoite membrane protein interactions reveals an essential role for the p24 complex in host infection [Research]

Sporozoites are a motile form of malaria-causing Plasmodium falciparum parasites that migrate from the site of transmission in the dermis through the bloodstream to invade hepatocytes. Sporozoites interact with many cells within the host, but the molecular identity of these interactions and their role in the pathology of malaria is poorly understood. Parasite proteins that are secreted and embedded within membranes are known to be important for these interactions, but our understanding of how they interact with each other to form functional complexes is largely unknown. Here, we compile a library of recombinant proteins representing the repertoire of cell surface and secreted proteins from the P. falciparum sporozoite and use an assay designed to detect extracellular interactions to systematically identify complexes. We identify three protein complexes including an interaction between two components of the p24 complex that is involved in the trafficking of glycosylphosphatidylinositol (GPI)-anchored proteins through the secretory pathway. Plasmodium parasites lacking either gene are strongly inhibited in the establishment of liver stage infections. These findings reveal an important role for the p24 complex in malaria pathogenesis and show that the library of recombinant proteins represents a valuable resource to investigate P. falciparum sporozoite biology.




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Interspecies differences in proteome turnover kinetics are correlated with lifespans and energetic demands [Research]

Cells continually degrade and replace damaged proteins. However, the high energetic demand of protein turnover generates reactive oxygen species (ROS) that compromise the long-term health of the proteome. Thus, the relationship between aging, protein turnover and energetic demand remains unclear. Here, we used a proteomic approach to measure rates of protein turnover within primary fibroblasts isolated from a number of species with diverse lifespans including the longest-lived mammal, the bowhead whale. We show that organismal lifespan is negatively correlated with turnover rates of highly abundant proteins. In comparison to mice, cells from long-lived naked mole rats have slower rates of protein turnover, lower levels of ATP production and reduced ROS levels. Despite having slower rates of protein turnover, naked mole rat cells tolerate protein misfolding stress more effectively than mouse cells. We suggest that in lieu of rapid constitutive turnover, long-lived species may have evolved more energetically efficient mechanisms for selective detection and clearance of damaged proteins.




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Separation and identification of permethylated glycan isomers by reversed phase nanoLC-NSI-MS [Research]

High performance liquid chromatography has been employed for decades to enhance detection sensitivity and quantification of complex analytes within biological mixtures. Among these analytes, glycans released from glycoproteins and glycolipids have been characterized as underivatized or fluorescently tagged derivatives by HPLC coupled to various detection methods. These approaches have proven extremely useful for profiling the structural diversity of glycoprotein and glycolipid glycosylation but require the availability of glycan standards and secondary orthogonal degradation strategies to validate structural assignments. A robust method for HPLC separation of glycans as their permethylated derivatives, coupled with in-line MSn fragmentation to assign structural features independent of standards, would significantly enhance the depth of knowledge obtainable from biological samples. Here, we report an optimized workflow for LC-MS analysis of permethylated glycans that includes sample preparation, mobile phase optimization, and MSn method development to resolve structural isomers on-the-fly. We report baseline separation and MSn fragmentation of isomeric N- and O-glycan structures, aided by supplementing mobile phases with Li+, which simplifies adduct heterogeneity and facilitates cross-ring fragmentation to obtain valuable monosaccharide linkage information. Our workflow has been adapted from standard proteomics-based workflows and, therefore, provides opportunities for laboratories with expertise in proteomics to acquire glycomic data with minimal deviation from existing buffer systems, chromatography media, and instrument configurations. Furthermore, our workflow does not require a mass spectrometer with high-resolution/accurate mass capabilities. The rapidly evolving appreciation of the biological significance of glycans for human health and disease requires the implementation of high-throughput methods to identify and quantify glycans harvested from sample sets of sufficient size to achieve appropriately powered statistical significance. The LC-MSn approach we report generates glycan isomeric separations, robust structural characterization, and is amenable to auto-sampling with associated throughput enhancements.




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Global lysine acetylation and 2-hydroxyisobutyrylation reveal the metabolism conversion mechanism in Giardia lamblia [Research]

Giardia lamblia (G. lamblia) disease is a zoonosis with a-infection rate affecting the general population of the world. Despite the constant possibility of damage due to their own metabolism, G. lamblia have survived and evolved to adapt to various environments. However, research on energy-metabolism conversion in G. lamblia is limited. This study aimed to reveal the dynamic metabolism-conversion mechanism in G. lamblia under sugar starvation by detecting global lysine acetylation and 2-hydroxyisobutyrylation sites combined with quantitative proteome analyses. A total of 2999 acetylation sites on 956 proteins and 8877 2-hydroxyisobutyryl sites on 1546 proteins were quantified under sugar starvation. Integrated Kac and Khib data revealed that modified proteins were associated with arginine biosynthesis, glycolysis/gluconeogenesis, and alanine, aspartate, and glutamate metabolism. These findings suggested that lysine acetylation and 2-hydroxyisobutyrylation were ubiquitous and provided deep insight into the metabolism-conversion mechanism in G. lamblia under sugar starvation. Overall, these results can help understand the biology of G. lamblia infections and reveal the evolution rule from prokaryote to eukaryote.




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Nuclear Disarmament and the Protection of Cultural Heritage

Nuclear Disarmament and the Protection of Cultural Heritage Research paper sysadmin 6 October 2017

States possessing nuclear weapons should be called upon to consider and publish the risks posed to cultural heritage, and their mitigation strategies, in their nuclear-weapons doctrines and policies.

A woman walks on the roof of the Great Mosque of Djenné, a World Heritage Site, after praying. Photo: United Nations.

Summary

  • Renewed risk assessments for nuclear weapons and policies are taking place around the world in light of nuclear modernization and the changing geostrategic environment that is making the use of nuclear weapons more likely. As such the humanitarian impacts of nuclear weapons and tests have received increased attention. However, the effect on cultural heritage has so far been neglected.
  • The potential for armed conflict to destroy cultural heritage has been recognized in international law since 1954. There is significant evidence on the impact of nuclear weapons on cultural heritage including the consequences of their use in Hiroshima and Nagasaki and the effect of nuclear-testing programmes in places of cultural significance since 1945. States that possess nuclear weapons have increased liabilities and responsibilities to protect cultural heritage and cultural rights. The need to protect cultural heritage should strengthen the case for reducing and eliminating nuclear weapons.
  • Failure to take into account the protection of heritage in the development of nuclear weapons policies – including disarmament, non-proliferation and arms-control negotiations – significantly undermines states’ existing commitments to protecting heritage threatened by conflict.
  • Risk assessments of the impact of nuclear weapons on cultural heritage and important cultural artefacts – and methods of preventing such catastrophic damage – should be part of protecting cultural heritage in every country and the subject of informed public debate. A new body of knowledge on the full range of nuclear weapons impacts would introduce a fresh perspective to inform decision-makers, international organizations and the public in thinking about nuclear weapons policies and practices.
  • Risk and resilience frameworks, which provide sets of solutions for risk assessments, would allow assessments of nuclear weapons threats to heritage and highlight vulnerabilities that need to be addressed. Such frameworks would provide a basis for policymakers to identify the world’s cultural heritage most at risk and help develop mitigation strategies to ensure that it is protected. In particular, states possessing nuclear weapons should be called upon to consider and publish the risks posed to cultural heritage, and their mitigation strategies, in their nuclear weapons doctrines and policies, as a contribution to transparency and confidence-building, and as a responsibility to the world’s shared heritage. International organizations, such as the UN Educational, Scientific, and Cultural Organization (UNESCO), have a role to play in bridging security perspectives with protecting cultural heritage.




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Gender-smart Procurement: Policies for Driving Change

Gender-smart Procurement: Policies for Driving Change Research paper sysadmin 14 December 2017

Governments should use public procurement policy as a strategic lever to accelerate gender-inclusive economic growth through the application of state spending power.

Entrepreneurs Virginia Santy and Melanie Ulle at Women in Kind, a co-working space aimed at small businesses run by women in Denver, US. Photo: Getty Images.

  • Governments need to rethink public procurement policy. They need to use it as a strategic lever to accelerate gender-inclusive economic growth through the application of state spending power, while maintaining rigorous governance standards. Reform of public procurement to make it more gender-inclusive could create a ‘diversity dividend’ through increased job creation and economic growth. Gender-smart procurement policies could also mitigate economic and business risk by rendering supply chains more diverse.
  • In 2014, G20 members agreed to reduce the gender gap in the labour market by 25 per cent by 2025. Procurement policy is one of the most powerful tools governments have to achieve this goal. All G20 members, regardless of the differences in their legal frameworks, can implement measures that will increase the ability of women to benefit from procurement policy.
  • Public procurement accounts for around one-fifth of global gross domestic product (GDP). It is estimated that women entrepreneurs supply only 1 per cent of this market. Women’s businesses face considerable barriers to accessing procurement tenders and winning procurement contracts. The inadequate design of many procurement processes prevents more inclusive gender outcomes for citizens. Governments should redefine procurement policies to make explicit the requirement that increasing women’s workforce participation, through greater use of female suppliers, is a key objective when selecting bids for procurement contracts.
  • Through the use of policy and spending levers, governments can play four primary roles in encouraging procurement from enterprises owned by women, or from businesses committed to promoting female labour participation. These roles are:
    - To direct reforms of government procurement – reviewing procurement policies and practices to ensure sustainable and inclusive procurement;
    - To reduce barriers to women’s participation in the economy – creating the support mechanisms to ensure an environment in which businesses owned by women can flourish;
    - To help scale up gender-smart procurement in the private sector – expanding government’s role in encouraging private companies to spend more of their procurement budgets with women’s businesses; and
    - To encourage increased transparency on the issues – creating and sharing procurement databases and lessons learned, especially at the regional level.
  • Companies can also benefit from having more diverse supply chains and volunteering for accreditation schemes. They can start conversations with government about national regulation that encourages diversity in procurement, leading by example.
  • The G20 should set measurable and time-bound targets in the area of gender-smart procurement, to build on the momentum of UN reforms and incorporate good practice in supply chain management.




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Prices, Products and Priorities: Meeting Refugees’ Energy Needs in Burkina Faso and Kenya

Prices, Products and Priorities: Meeting Refugees’ Energy Needs in Burkina Faso and Kenya Other resource sysadmin 24 January 2018

As the number of displaced people increases, and aid budgets come under further pressure, the imperative to identify cost-effective and sustainable solutions for delivering energy to refugees is more pressing than ever.

Father and daughter in their shelter in Goudoubo refugee camp, Burkina Faso, March 2017. Photo: Kwesi Annim.

This paper examines the issue of energy and displacement in detail, using insights from refugees in camps in Burkina Faso and Kenya. It seeks to promote a better understanding of their energy needs, priorities and preferences, and explores how increased access to energy might help to achieve lasting impact in the two camps surveyed. The paper is based on primary research from the Goudoubo camp in Burkina Faso and the Kakuma I camp in Kenya, but the analysis and conclusions are pertinent in the wider context of camps for forcibly displaced people.

  • There is a low level of energy access in the refugee camps of Kakuma I and Goudoubo, which contributes to poverty and hampers relief and development efforts. Trying to meet basic cooking, lighting and phone-charging needs is costly for refugees, consuming a significant share of stretched monthly budgets.
  • The predominant cooking solution consists of basic improved cookstoves burning wood and charcoal. The ‘three-stone fire’ method also remains commonplace. Three out of five families in Kakuma I report health problems due to smoke from cookstoves.
  • Street lighting is a high priority for residents, due to concerns about security and safety in camps. In Goudoubo, 86 per cent of survey respondents said that more household members would go out after dark if there were better public lighting.
  • A significant proportion of refugees would pay for cleaner and more efficient energy technologies, but many lack the financial resources required, and the development of markets for such products remains partially contingent on sustained financial support.
  • There is a need for a diversity of energy technologies that give varying levels and qualities of service; a ‘one size fits all’ approach is inappropriate if universal access to sustainable energy is to be achieved.
  • Clean cookstoves and fuels (LPG, ethanol, biogas, etc.) are in high demand, but require much greater investment if they are to be introduced at scale. Solid biomass and improved cookstoves will continue to be important cooking solutions in Kakuma I and Goudoubo, as well as in other refugee camps. A shift to more efficient cooking can be achieved at little or no extra cost for the significant proportion of people who still cook on three-stone fires.
  • Users of quality-verified household solar products spend dramatically less on light and power than do people using inferior technologies. Strong brand recognition and a high willingness to pay indicate a large market and a significant opportunity for the solar private sector.
  • Centralized electricity supply solutions – mini-grids or grid connections – are more economic than multiple standalone diesel generators. The current piecemeal and ad hoc approach, with each facility managing its own power supply, is inherently wasteful. Greater coordination among humanitarian clusters is required so that centralized solutions can be assessed, designed, financed and implemented.
  • Collecting data on energy expenditure and use, as well as quantification of the wide ranging impacts of improved technologies, is necessary to build a compelling case for investment in electricity infrastructure. In addition, engaging refugees on their needs, preferences and willingness to pay can improve the sustainability and impact of energy interventions.
  • Private-sector and market development approaches offer long-term, cost-effective solutions for refugees and can also benefit host communities. As the number of displaced people in the world increases, and as aid budgets come under further pressure, the imperative to identify cost-effective and sustainable solutions is more pressing than ever.

Chatham House is a part of the Moving Energy Initiative, a consortium working towards clean energy for refugees. For more information visit movingenergy.earth




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Proportionality in the Conduct of Hostilities: The Incidental Harm Side of the Assessment

Proportionality in the Conduct of Hostilities: The Incidental Harm Side of the Assessment Research paper sysadmin 6 December 2018

Clarification of international humanitarian law is important in ensuring compliance with the rule of proportionality, but a culture of compliance within armed forces and groups is also crucial.

Members of civil right defence conduct a search and rescue operation on destroyed buildings after an airstrike was carried out over the city of Jisr al-Shughur in Idlib province in Syria, on 6 May 2018. Photo: Hadi Harrat/Anadolu Agency/Getty Images.

Summary

  • Military operations are taking place with increasing frequency in densely populated areas. Such operations result in loss of life and harm to civilians, as well as damage to civilian objects, (including infrastructure providing essential services). In order to protect civilians, it is imperative that armed forces and groups comply with the rules of international humanitarian law on the conduct of hostilities, including the rule of proportionality.
  • The rule of proportionality prohibits attacks which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated. This research paper analyses the key steps that belligerents must take to give effect to the rule, with a particular focus on one side of proportionality assessments – the expected incidental harm.
  • Those undertaking proportionality assessments before or during an attack must consider whether the expected harm will be caused by the attack, and whether that harm could be expected (that is, was it reasonably foreseeable).
  • For the purpose of proportionality assessments, injury to civilians includes disease, and there is no reason in principle to exclude mental harm, even though it is currently challenging to identify and quantify it. Damage to civilian objects includes damage to elements of the natural environment.
  • Once the incidental harm to be considered has been identified, a value or weight must be assigned to it. This is then balanced against the value or weight of the military advantage anticipated from the attack to determine whether the harm would be excessive.
  • In the determination of whether the expected incidental harm would be excessive compared to the anticipated military advantage, ‘excessive’ is a wide but not indeterminate standard.
  • Belligerents should develop methodologies so that those planning and deciding attacks are provided with all necessary information on expected incidental harm, and to assist them in assigning weight to the incidental harm to be considered.
  • If it becomes apparent that the rule of proportionality will be contravened, the attack in question must be cancelled or suspended.
  • Clarification of the law is important in ensuring compliance with the rule of proportionality, but a culture of compliance within armed forces and groups, inculcated by their leaders, is also crucial.