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Brook E Heaton, Edward M Kennedy, Rebekah E Dumm, Alfred T Harding, Matthew T Sacco, David Sachs, Nicholas S Heaton
Influenza A virus (IAV) is a pathogen that poses significant risks to human health. It is therefore critical to develop strategies to prevent influenza disease. Many loss-of-function screens have been performed to identify the host proteins required for viral infection. However, there has been no systematic screen to identify the host factors that, when overexpressed, are sufficient to prevent infection. In this study, we used CRISPR/dCas9 activation technology to perform a genome-wide overexpression screen to identify IAV restriction factors...
August 15, 2017: Cell Reports
Christopher J Vavricka, Chiaki Muto, Tomohisa Hasunuma, Yoshinobu Kimura, Michihiro Araki, Yan Wu, George F Gao, Hiroshi Ohrui, Minoru Izumi, Hiromasa Kiyota
The design, synthesis and application of N-acetylneuraminic acid-derived compounds bearing anomeric sulfo functional groups are described. These novel compounds, which we refer to as sulfo-sialic acid analogues, include 2-decarboxy-2-deoxy-2-sulfo-N-acetylneuraminic acid and its 4-deoxy-3,4-dehydrogenated pseudoglycal. While 2-decarboxy-2-deoxy-2-sulfo-N-acetylneuraminic acid contains no further modifications of the 2-deoxy-pyranose ring, it is still a more potent inhibitor of avian-origin H5N1 neuraminidase (NA) and drug-resistant His275Tyr NA as compared to the oxocarbenium ion transition state analogue 2,3-dehydro-2-deoxy-N-acetylneuraminic acid...
August 15, 2017: Scientific Reports
Daniel E K Kabotso, Nicola L B Pohl
S-Propyl glycosides of less activated sugars, such as peracetylated carbohydrates and uronic acid esters that could not previously be activated with triphenylbismuth ditriflate alone, were found to be glycosylated in the presence of propanethiol as an additive in under 3 h. This newly developed protocol was also found to be effective in promoting glycosylation of neutral and uronic acid esters of S-phenyl, S-thiazolinyl, S-benzoxazolyl, and S-adamantyl glycosides as well as sialic acid.
August 15, 2017: Organic Letters
Takashi Nishikaze
Mass spectrometry (MS) has become an indispensable tool for analyzing post translational modifications of proteins, including N-glycosylated molecules. Because most glycosylation sites carry a multitude of glycans, referred to as "glycoforms," the purpose of an N-glycosylation analysis is glycoform profiling and glycosylation site mapping. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has unique characteristics that are suited for the sensitive analysis of N-glycosylated products...
2017: Mass Spectrometry
Shuang Yang, Ewa Jankowska, Martina Kosikova, Hang Xie, John F Cipollo
Differentiation between the sialyl linkages is often critical to understanding biological consequence. Here we present a facile method for determining these linkages in glycans. Analysis of sialic acids is challenging due to their labile nature during sample preparation and ionization. Derivatization is often required via chemical reaction. Amidation derivatizes all sialic acids regardless of linkage, while esterification enables differentiation between α2,3-linked and α2,6-linked sialic acids. Reactions have been primarily performed on free glycans in solution but have been recently adapted to solid-phase providing unique advantages such as simplified sample preparation, improved yield, and high throughput applications...
August 9, 2017: Analytical Chemistry
P Chiodelli, S Rezzola, C Urbinati, F Federici Signori, E Monti, R Ronca, M Presta, M Rusnati
Vascular endothelial growth factor receptor-2 (VEGFR2) is the main pro-angiogenic receptor expressed by endothelial cells (ECs). Using surface plasmon resonance, immunoprecipitation, enzymatic digestion, immunofluorescence and cross-linking experiments with specific sugar-binding lectins, we demonstrated that VEGFR2 bears both α,1-fucose and α(2,6)-linked sialic acid (NeuAc). However, only the latter is required for VEGF binding to VEGFR2 and consequent VEGF-dependent VEGFR2 activation and motogenic response in ECs...
August 7, 2017: Oncogene
Selasi Dankwa, Mudit Chaand, Usheer Kanjee, Rays H Y Jiang, Luis V Nobre, Jonathan M Goldberg, Amy K Bei, Mischka A Moechtar, Christof Grüring, Ambroise D Ahouidi, Daouda Ndiaye, Tandakha N Dieye, Souleymane Mboup, Michael P Weekes, Manoj T Duraisingh
Plasmodium falciparum, the parasite that causes the deadliest form of malaria, has evolved multiple proteins known as invasion ligands that bind to specific erythrocyte receptors to facilitate invasion of human erythrocytes. The EBA-175/glycophorin A (GPA) and Rh5/basigin ligand-receptor interactions, referred to as invasion pathways, have been the subject of intense study. In this study, we focused on the lesser characterized sialic acid-containing receptors glycophorin B (GPB) and glycophorin C (GPC). Through bioinformatic analysis, we identified extensive variation in glycophorin B transcript (GYPB) levels in individuals from Benin, suggesting selection from malaria pressure...
July 31, 2017: Infection and Immunity
Kohta Takahashi, Sergei Proshin, Kazunori Yamaguchi, Yoji Yamashita, Ryuichi Katakura, Koji Yamamoto, Hiroshi Shima, Masahiro Hosono, Taeko Miyagi
BACKGROUND: Glioblastoma multiforme is one of the most malignant tumors of the human central nervous system characterized by high degree of invasiveness. Focusing on this invasive nature, we investigated whether ganglioside-specific sialidase NEU3 might be involved, because gangliosides are major components of brain tissues, and cell surface sialic acids, as target residues of sialidase catalysis, are thought to be closely related to cell invasion. METHODS: NEU3 mRNA levels of human glioblastoma specimens were evaluated by quantitative RT-PCR...
July 29, 2017: Biochimica et Biophysica Acta
Abhishek Kumar Singh, Sandeep Singh, Geetika Garg, Syed Ibrahim Rizvi
Erythrocyte membrane is a suitable model to study various metabolic and physiological functions as it undergoes variety of biochemical changes during aging. An age-dependent modulatory effect of rapamycin on erythrocyte membrane functions is completely unknown. Therefore, the present study was undertaken to investigate the effect of rapamycin on age-dependent impaired activities of transporters/exchangers, altered levels of redox biomarkers, viz. protein carbonyl (PC), lipid hydroperoxides (LHs), total thiol (-SH), sialic acid (SA) and intracellular calcium ion [Ca(2+)]i, and osmotic fragility of erythrocyte membrane...
July 31, 2017: Archives of Physiology and Biochemistry
Ji-Yun Kim, Deok-Song Kim, Ja-Young Seo, Jun-Gyu Park, Mia Madel Alfajaro, Mahmoud Soliman, Yeong-Bin Baek, Eun-Hyo Cho, Hyung-Jun Kwon, Su-Jin Park, Mun-Il Kang, Kyoung-Oh Cho
Group A rotaviruses (RVAs) are divided into neuraminidase (NA)-sensitive and NA-insensitive strains depending upon their binding affinity to the VP8* domain in the terminal sialic acids (SAs) of cell surface carbohydrates. Although NA-sensitive strains are known to use terminal SAs as an attachment factor, the exact nature of this attachment factor is largely unknown. Here we show that the specific linkage of SA-containing glycan to glycoprotein or glycolipid is an attachment factor used by NA-sensitive porcine G9P[7] PRG9121 and G9P[23] PRG942, bovine G6P[1] NCDV, and canine G3P[3] strains...
August 2017: Veterinary Microbiology
Ajit Varki
Given varied intrinsic and extrinsic challenges to the immune system, it is unsurprising that each evolutionary lineage evolves distinctive features of immunoreactivity, and that tolerance mechanisms fail, allowing autoimmunity. Humans appear prone to many autoimmune diseases, with mechanisms both genetic and environmental. Another rapidly evolving biological system involves sialic acids, a family of monosaccharides that are terminal caps on cell surface and secreted molecules of vertebrates, and play multifarious roles in immunity...
July 26, 2017: Journal of Autoimmunity
Kim M Summers, David A Hume
The FANTOM5 consortium used cap analysis of gene expression (CAGE) to analyze the time course of gene expression over development from 11 days postcoitum (dpc) to adult in 16 developing organs and the whole body of the mouse. Every tissue in the body contains a large number of resident macrophages that initially infiltrate the embryo from the yolk sac. These cells contribute to organogenesis, and their functions diversify during development as they acquire tissue-specific adaptations. In each of the FANTOM5 time courses, the expression of known macrophage-specific genes, including CSF1 receptor (Csf1r), epidermal growth factor-like module-containing mucin-like hormone receptor-like 1 (Emr1), and mer receptor tyrosine kinase (Mertk), was readily detectable and increased with time...
July 27, 2017: Journal of Leukocyte Biology
Asako Shimoda, Yoshiro Tahara, Shin-Ichi Sawada, Yoshihiro Sasaki, Kazunari Akiyoshi
Studies involving the functional analysis of exosomal contents including proteins, DNA, and RNA have been reported. Most membrane proteins and lipids are glycosylated, which controls their physical properties and functions, but little is known about glycans on exosomes owing to the difficulty of analysing them. To shed light on these issues, we collected exosomes from mesenchymal stem cells (MSCs) derived from human adipose tissue for glycan profiling using evanescent-field fluorescence-assisted lectin array as well as analysis of their uptake in vivo...
July 24, 2017: Biochemical and Biophysical Research Communications
Nina Gratz, Lip Nam Loh, Beth Mann, Geli Gao, Robert Carter, Jason Rosch, Elaine I Tuomanen
Neuraminidase A (NanA) is an important virulence factor that is anchored to the pneumococcal cell wall and cleaves sialic acid on host substrates. We noted that a secreted allele of NanA was over-represented in invasive pneumococcal isolates and promoted the development of meningitis when swapped into the genome of non-meningitis isolates replacing cell wall-anchored NanA. Both forms of recombinant NanA directly activated transforming growth factor (TGF)-β, increased SMAD signalling and promoted loss of endothelial tight junction ZO-1...
July 28, 2017: Microbiology
Shoib S Siddiqui, Stevan A Springer, Andrea Verhagen, Venkatasubramaniam Sundaramurthy, Frederico Alisson-Silva, Weiping Jiang, Pradipta Ghosh, Ajit Varki
The immunomodulatory receptor Siglec-3/CD33 influences risk for late-onset Alzheimers disease (LOAD), an apparently human-specific post-reproductive disease. CD33 generates two splice variants: a full-length CD33M transcript produced primarily by the LOAD-risk allele and a shorter CD33m isoform lacking the sialic acid-binding domain, produced primarily from the LOAD-protective allele. A SNP that modulates CD33 splicing to favor CD33m is associated with enhanced microglial activity. Individuals expressing more protective isoform accumulate less brain Beta-amyloid and have a lower LOAD risk...
July 26, 2017: Journal of Biological Chemistry
Shani Leviatan Ben-Arye, Hai Yu, Xi Chen, Vered Padler-Karavani
Cells are covered with a cloak of carbohydrate chains (glycans) that is commonly altered in cancer and that includes variations in sialic acid (Sia) expression. These are acidic sugars that have a 9-carbon backbone and that cap vertebrate glycans on cell surfaces. Two of the major Sia forms in mammals are N-acetylneuraminic acid (Neu5Ac) and its hydroxylated form, N-glycolylneuraminic acid (Neu5Gc). Humans cannot produce endogenous Neu5Gc due to the inactivation of the gene encoding cytidine 5'monophosphate-Neu5Ac (CMP-Neu5Ac) hydroxylase (CMAH)...
July 13, 2017: Journal of Visualized Experiments: JoVE
Cui Cao, Wen J Wang, Ying Y Huang, Hong L Yao, Louis P Conway, Li Liu, Josef Voglmeir
CMAH (cytidine monophosphate-N-acetylneuraminic acid hydroxylase) is responsible for the oxidation of cytidine monophosphate-N-acetylneuraminic acids in mammals. However, humans cannot oxidize cytidine monophosphate-N-acetylneuraminic acid to cytidine monophosphate-N-glycolylneuraminic acid due to a primary exon deletion of the CMAH gene. To understand the effects and implications of the lack of CMAH activity in more detail, a Cmah knock-out model in mice is of keen interest in basic and applied research. The analysis method to determine the phenotype of this mouse model is herein described in detail, and is based on the detection of both N-acetylneuraminic acid and N-glycolylenuraminic acid in the liver and milk of wild-type and Cmah knock-out mice...
July 14, 2017: Journal of Visualized Experiments: JoVE
Leonardo Freire-de-Lima, Luciana B Gentile, Leonardo M da Fonseca, Kelli M da Costa, Jessica Santos Lemos, Lucas Rodrigues Jacques, Alexandre Morrot, Célio G Freire-de-Lima, Marise P Nunes, Christina M Takiya, Jose O Previato, Lucia Mendonça-Previato
Trans-sialidase from Trypanosoma cruzi (Tc-TS) belongs to a superfamily of proteins that may have enzymatic activity. While enzymatically active members (Tc-aTS) are able to transfer sialic acid from the host cell sialyl-glycoconjugates onto the parasite or to other molecules on the host cell surface, the inactive members (Tc-iTS) are characterized by their lectinic properties. Over the last 10 years, several papers demonstrated that, individually, Tc-aTS or Tc-iTS is able to modulate several biological events...
2017: Frontiers in Microbiology
Marta Utratna, Heidi Annuk, Jared Q Gerlach, Yuan C Lee, Marian Kane, Michelle Kilcoyne, Lokesh Joshi
There is an urgent need for discovery of novel antimicrobials and carbohydrate-based anti-adhesive strategies are desirable as they may not promote resistance. Discovery of novel anti-adhesive molecules from natural product libraries will require the use of a high throughput screening platform. Avian egg white (EW) provides nutrition for the embryo and protects against infection, with glycosylation responsible for binding certain pathogens. In this study, a microarray platform of 78 species of avian EWs was developed and profiled for glycosylation using a lectin panel with a wide range of carbohydrate specificities...
July 25, 2017: Scientific Reports
Jiexiong Xie, Isaura Christiaens, Bo Yang, Wander Van Breedam, Tingting Cui, Hans J Nauwynck
In recent years, several entry mediators have been characterized for porcine reproductive and respiratory syndrome virus (PRRSV). Porcine sialoadhesin [pSn, also known as sialic acid-binding immunoglobulin-type lectin (Siglec-1)] and porcine CD163 (pCD163) have been identified as the most important host entry mediators that can fully coordinate PRRSV infection into macrophages. However, recent isolates have not only shown a tropism for sialoadhesin-positive cells, but also for sialoadhesin-negative cells. This observation might be partly explained by the existence of additional receptors that can support PRRSV binding and entry...
July 26, 2017: Journal of General Virology
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