Day 2 :
Keynote Forum
Neil P.J. Price
National Center for Agricultural Utilization Research, USA
Keynote: Tunicamycins: translocase-I inhibitors that target bacterial cell wall and mammalian N-glycoproteins. The potential for selective inhibitors
Time : 10:05 -10:30
Biography:
Neil Price has a PhD from the University of London and has Postdoctoral experience at the University of Geneva in Switzerland, Paul-Sabatier University in Toulouse and the Complex Carbohydrate Research Center in Athens. He held a Faculty Position the University of Rochester, NY before moving to the NCAUR, Peoria. His research includes carbohydrate chemistry and biochemistry, mass spectrometry and microbial metabolism. He currently serves on the ARS National Chemical Patent committee and has over 90 peer-reviewed research publications.
Abstract:
Tunicamycins are a heterologous family of nucleoside antibiotics that target the biosynthesis of bacterial peptidoglycan and eukaryotic N-glycoproteins. The mechanism of action is known, with the tunicamycin-Mg2+ complex established as a transition state analog for hexosamine-1-phosphate:prenol phosphate translocases. Hence, this inhibits the formation of N-acetylmuramyl-undecanol pyrophosphate in bacteria or N-acetylglucosamine-dolichol pyrophosphate in eukaryotes, which are essential intermediates in these organisms. We have investigated the biosynthesis of the tunicamycins by certain streptomyces species, and have proposed a pathway in which the 11-carbon dialdose sugar, tunicamine, is derived from uridine and N-acetylglucosamine. Once formed the uridyl-tunicaminyl intermediate is α,β-1,11-glycosylated and N-acylated to form the bioactive compounds prior to secretion. Heterologous expression identified twelve tun genes (tunA – tunL) responsible for tunicamycin biosynthesis in the producing organisms Streptomyces chartreusis and S. clavuligerus. Amongst these is a putative radical SAM enzyme (TunB) with a potentially unique role in biosynthetic carbon-carbon bond formation, and an unusual glycosyltransferase (TunD) involved in the formation of the anomeric-to-anomeric α,β-1,11-glycosidic bond. Hence, a biosynthetic pathway is proposed for tunicamycin biosynthesis which may be useful for the design of new tunicamycin analogs with selective/enhanced translocase specificity.
Keynote Forum
Myron R Szewczuk
Queen’s University, Canada
Keynote: Role of Glycosylation in TOLL-like Receptor Activation and Pro-Inflammatory Responses
Time : 10:30-10.55
Biography:
Myron Szewczuk has completed his PhD 1974 from University of Windsor in Biology and Immunochemistry and his postdoctoral studies from Cornell University Medical College, New York City, U.S.A. in Cellular immunology with Dr. Greg Siskind (1975-1978). He is presently Full Professor of Immunology and Associate Professor of Medicine, Queen’s University, Kingston, Ontario, Canada. He has published more than 100 papers in reputed journals and has been serving as an editorial board member of repute.
Abstract:
The mammalian Toll-like receptors (TLRs) are one of the families of sensor receptors that recognize pathogen-associated molecular patterns (PAMPs). Not only are TLRs crucial sensors of microbial (e.g., viral, bacterial and parasitic) infections in innate immune cells, they also play important roles in the pathophysiology of infectious, inflammatory and autoimmune diseases. Thus, the intensity and duration of TLR responses against invading microbial pathogens and endogenous danger signals must be tightly controlled. It follows that studies on the structural integrity of TLRs, their ligand interactions and signaling components may provide important information essential to our understanding of TLR-dependent immunological protection and disease intervention. Although the signaling pathways of TLR sensors are well characterized, the parameters controlling interactions between these receptors and their ligands still remain poorly defined. Here, the presentation will highlight the role of glycosylation and sialylation in TLR activation. The key interactions that induce TLR activation are identified and a novel TLR-signaling platform is identified. A mammalian neuraminidase-1 (Neu1 sialidase) and matrix metalloproteinase-9 (MMP-9) cross-talk in alliance with the G-protein coupled receptor (GPCR) neuromedin B is uncovered which is essential for cell surface and intracellular TLR-induced receptor activation, cellular signaling and pro-inflammatory responses.
- Track 4 : Glycobiology: Its Role In Human Health
Track 5 : Discovery and Classification of Glycan Binding Proteins
Track 6 : Glycan Catabolism and Systemic Physiology
Track 7 : Evolution of Glycan Diversity
Location: Independence C
Chair
Neil P.J. Price
National Center for Agricultural Utilization Research, USA
Co-Chair
Myron R Szewczuk
Queen’s University, Canada
Session Introduction
Neil P. J. Price
National Center for Agricultural Utilization Research, U.S.A
Title: Liamocins, sophorolipids and frost grape polysaccharides. New carbohydrate research from the USDA’s NCAUR national laboratory
Time : 11-10-11:30
Biography:
Neil Price has a Ph.D. from the University of London, and has postdoctoral experience at the Univ. of Geneva in Switzerland, Paul-Sabatier University in Toulouse, and the Complex Carbohydrate Research Center in Athens, GA. He held a faculty position the U. of Rochester, NY before moving to the NCAUR, Peoria. His research includes carbohydrate chemistry and biochemistry, mass spectrometry, and microbial metabolism. He currently serves on the ARS National Chemical Patent committee, and has over 90 peer-reviewed research publications.
Abstract:
The USDA’s National Center for Agricultural Utilization Research has a prominent history in carbohydrate research, including the development of xanthan gum, ‘super slurper’ polysaccharides, beta-dextrans, alternan, and beta lactamase antibiotics (penicillins), as well as analytical tools such as aldononitrile acetates. This presentation will focus on three more recent innovations: sophorolipid bio-surfactants; liamocin anti-microbial agents; and frost grape polysaccharide. Sophorolipids (SLs) can be produced by fermentation, often in high yield (50 – 400 g/L), by yeasts of the Starmarella clade. The SLs are composed of a sophorose sugar head group (Glc-beta-1,2-Glc) glycosidically attached to a hydroxyl fatty acid. In a MALDI-TOF MS-based screen of Starmarella yeast we found that Candida kuoi NRRL Y-27208 produces non-lactone type SLs in which the sophorose is O-linked to ω-hydroxy fatty acids. Unlike the more common lactone-type SLs, these novel SL’s have an open chain structure that confers low-foaming bio-surfactant properties. The liamocins are novel polyol-lipids from a black yeast-like fungus, Aureobasidium pullulans. Four liamocins have been characterized from Aureobasidium NRRL 50380 that contain a mannitol head-group linked to several polyester-linked 3,5-dihydroxydecanoate acyl chains. Two of the liamocins are also 3’-O-acetylated, and all four have pronounced antimicrobial properties. A new, high molecular weight polysaccharide has also been found to be produced by the frost grape (Vitis riparia), and the structural characterization and properties of this will also be presented and discussed.
Pi-Wan Cheng
University of Nebraska Medical Center, USA
Title: Disregulation of golgi localization of glycosyltransferases alters mucin o-glycosylation and survival or metastatic properties of cancer cells
Time : 11.30-11.50
Biography:
Pi-Wan Cheng received his PhD degree in Biochemistry from Case Western Reserve University in 1975 and is currently a Professor of Biochemistry and Molecular Biology at the University of Nebraska Medical Center. He has published more than 95 papers mostly in Glycobiology field and has served in grant review panels of many funding agencies, including NIH, states and nonprofit organizations. He is a member of the editorial boards of the Journal of Glycobiology and the American Journal of Respiratory Cell and Molecular Biology.
Abstract:
Glycosylation is a posttranslational, template-independent process. Mucin O-glycosylation is catalyzed by glycosyltransferases (GTs) localized at various Golgi stacks according to the glycosylation steps they participate in. We have identified three different Golgi targeting sites for GTs. Giantin is the exclusive site for core 2 N-acetylglucosaminyltransferases (C2GnTs) and the primary site for Galβ3GalNAc:α2-3sialyltransferase 1 (ST3Gal1), GM130-GRASP65 is the primary site for core 1 synthase (C1GalT1) and the secondary site for ST3Gal1, and GM130-giantin is the secondary site for C1GalT1. Defective giantin in aggressive prostate cancer cells prevents C2GnTs but not other GTs from targeting the Golgi. As a result, core 2-associated glycans, such as polylactosamine, cannot be formed but sialyl-T level is elevated. Inhibition or knockdown of non-muscle myosin IIA restores giantin structure, normal Golgi targeting of GTs and core 2-associated polylactosamine, which renders these cancer cells susceptible to galectin 1-induced apoptosis. The result demonstrates that aggressive prostate cancer cells acquire survival advantage by altering Golgi targeting of GTs. This process does not require any change in the expression of GT genes. Also, we have identified proteins that help retain C2GnTs in the Golgi; Golgi phosphoprotein 3 (GOLPH3) for C2GnT-L and keratin 1 for C2GnT-M. Loss of keratin 1 prevents Golgi localization of C2GnT-M and increases sialyl-T level. Loss of GOLPH3 prevents Golgi retention of C2GnT-L, causes loss of selectin ligand sialyl Lewis x and decreases selectin-mediated metastatic properties. In conclusion, disregulation of Golgi targeting or retention of GTs can alter mucin O-glycosylation and survival or metastatic properties of cancer cells.
Ying Qing Yu
Waters Corporation, USA
Title: N-linked glycan characterization and profiling: combining the power of a novel labeling reagent and a streamlined analytical platform for confident glycan assignments
Time : 11:50-12:10
Biography:
Ying Qing is a Principal Scientist in the Pharmaceutical group at Waters Corporation. She joined Waters Corporation since 2001, shortly after she received her Ph.D. from the Analytical Chemistry Department at Purdue University. She is a group leader in the Biopharmaceutical lab unit at Waters. Her group’s focus is on Protein Biotherapeutics characterization using UPLC/QTOF MS platform. The projects she is currently working on range from glycan profiling, peptide mapping and lately the Hydrogen Deuterium Exchange Mass Spectrometry for protein higher order structure analysis. She has extensive experience in Mass Spectrometry, Gas-Phase Ion Chemistry and Liquid Chromatography Separation Techniques.
Abstract:
UPLC/FLR/MS(MS) analysis of released N-glycans labeled with a fluorescent tag has made routine with high performance LC and MS instrumentations. Glycans labeled with conventional fluorescent tags, such as 2-AB and 2-AA, can be detected by Fluorescent (FLR) detector with ultra-high sensitivity. Unlike FLR detector, mass spectrometry is known to be less sensitive to detect native or tagged glycans, especially the low abundant ones, due to their poor ESI performance. The limited dynamic range of this approach has been restricting the utilization of this combined automated workflow for glycan characterization. In order to overcome the low MS ionization efficiency associated with the conventional labels and confidently assign lower level glycans, a novel tag, RapiFluor-MSTM (RFMS) developed by Waters Corporation, has been employed. RFMS contains a rapid tagging reactive group, an efficient fluorophore, and a functional group that imparts high ionization efficiency. Complete tagging of glycans can be achieved in less than 5 minutes using this novel reagent. Initial results with the new glycan label show significant enhancement in both the FLR and MS(MS) signals compared to 2-AB. The increased sensitivity enables the detection and identification of very low level glycans at (0.1%) with sufficient MS signals. In this study, we demonstrate the benefits of combining the novel labeling reagent RFMS with an integrated UPLC/FLR/Xevo G2-XS QTOF MS system for detailed characterization of the minor glycoforms from therapeutical proteins.
Thomas J. Boltje
Radboud University, The Netherlands
Title: New tools to study and perturb the glycocalyx
Time : 12:10-12:30
Biography:
Thomas J. Boltje obtained his PhD degree in 2011 from the University of Georgia under the supervision of Prof. Dr. G.J. Boons. After a short postdoctoral period at the Radboud University Nijmegen (The Netherlands), he started his current position as a tenure track assistant professor of chemical biology in 2013 at the same university.
Abstract:
Our research is focused on identifying the specific structure and function of sugar molecules present on the surface of cells. To achieve this we develop tools to block the biosynthesis of these molecules and metabolic precursors to follow and perturb the function of sugars. In addition we assemble oligosaccharides by chemical synthesis to construct a screening platform that can also be used to do SAR studies. The preparation of oligosaccharides is challenging and hence we develop new chemical methodologies to make the process of glycosylation faster and more stereoselective. The most important application of these technologies is to enable the design and synthesis of glycomedicine that target aberrant glycosylation patterns on cancer cells and pathogenic bacteria either by small molecule glycomimetics or oligosaccharide glycovaccines.
Fiona Haxho
Queen’s University, Canada
Title: Role of G protein-coupled receptors in insulin receptor glycosylation and activation
Time : 12:30-12:50
Biography:
F. Haxho is a graduate trainee in Dr. Myron Szewczuk’s laboratory, Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada. She holds the Queen’s Graduate Award (QGA), Graduate Entrance Tuition Award (GETA) and the NSERC Alexander Graham Bell Canada Graduate Scholarship-Master’s (CGS M).
Abstract:
The insulin receptor (IR) is a transmembrane tyrosine kinase receptor (RTK) that is activated by insulin and insulin growth factors-I and II. Metabolically, insulin-induced IR activation plays a key role in the regulation of glucose homeostasis. A dysfunctional process of insulin-induced IR activation may result in a range of clinical manifestations including insulin resistance, type 2 diabetes mellitus, obesity, cancer, hypertension, and cardiovascular disorders. Although signal transduction pathways for many tyrosine kinase receptors, including IR, are generally well characterized, parameters controlling the activation of these receptors have remained poorly defined. Our recent reports describe a novel G-protein coupled receptor (GPCR)-signaling platform to potentiate mammalian neuraminidase-1 (Neu1) and matrix metalloproteinase-9 (MMP9) cross-talk in regulating RTKs, and specifically IR. Central to this regulatory signaling axis is that Neu1, MMP9 and neuromedin-B GPCR form a complex with the IRβ-subunit on the cell surface. This signaling paradigm proposes that insulin binding to its receptor on the cell surface induces a conformational change of the receptor to initiate GPCR Giα-signaling and MMP9 activation to induce Neu1. Activated Neu1 hydrolyzes α-2,3-sialyl residues linked to β-galactosides, which are distant from the insulin binding sites. These findings support a prerequisite desialylation process by activated Neu1 enabling the removal of steric hindrance to IRβ subunit association and the activation of tyrosine kinases. These reports uncover an unprecedented mode of control for insulin-induced IR activation and present an innovative platform for targeting hormone signaling by the modification of IR glycosylation.
Agata Steenackers
Lille 1 University, France
Title: Expression of OGT correlates with migration and proliferation of colon cells lines
Time : 13:35-13:55
Biography:
Agata Steenackers defended her PhD thesis in the field of Biology and Biotechnologies in November 2013 at the Lille 1 University (France). During her PhD, she developed a project around the expression of GD3 synthase and gangliosides in breast cancer cells lines. She is now on a post-doctoral position in Tony Lefebvre's team (UGSF) where she is studying the role of O-GlcNAcylation in colon cancer development.
Abstract:
The O-GlcNAc transferase (OGT) is a key regulator of the post-translational modification of proteins by O-linked β-N-acetylglucosamine (O-GlcNAc) onto Ser/Thr residues. OGT uses the end product of the hexosamine biosynthetic pathway (HBP), UDP-GlcNAc, as a donor for O-GlcNAcylation processes. It is reported that OGT and O-GlcNAcylation levels are increased in cancers. We showed that in the colorectal cancers (CRC) cell lines (HT29, HCT116) the expression of OGT and O-GlcNAcylation level were elevated, and that O-GlcNAcylation directly interfered with β-catenin stability and proliferation of cells. Previous studies showed that oncogenic factors such as p53, MYC or β-catenin are O-GlcNAcylated. The Wnt/β-catenin pathway is modified in most CRC by genetic alteration of β-catenin or one member of the destruction complex. Consequently, β-catenin is protected from proteasomal degradation and therefore induces cell proliferation. A similar observation was made when HBP flux was increased by culturing cells in high glucose medium. In these conditions, ï¢-catenin was protected against the degradation thus accelerating cell proliferation. In a recent study, we identified four O-GlcNAcylation sites at the N-terminus of β-catenin, one of those (T41) localized in the destruction box is crucial for the control of β-catenin degradation. In that context we studied the effect of OGT silencing in CRC cell lines and non-cancer cell line CCD841CoN. We reported that silencing of OGT halved proliferative and migratory capacities of cancer cells. OGT knock-down also diminished cell adhesion corroborating previous observations that inhibiting O-GlcNAcylation decreases β-catenin/α-catenin interactions necessary for mucosa integrity, which suggests that O-GlcNAcylation also affects localization of ï¢-catenin at adherens junction level.
Steffi Baldini
Lille 1 University, France
Title: Regulation of hepatic fatty acid synthase properties by O-glcnacylation in vivo and ex vivo
Time : 13:55-14:15
Biography:
Steffi Baldini is PhD student in the field of Biology and Biotechnologies since September 2013 at the Lille 1 University (France). During her PhD, she develops a project around the regulation of hepatic Fatty Acid Synthase expression by O-GlcNAcylation.
Abstract:
During meal intake, two metabolic pathways are activated in the liver, the glycolysis and the lipogenesis, to drive the production of fatty acids. The Hexosamine Biosynthesis Pathway (HBP), which end product is UDP-GlcNAc the substrate of OGT (O-GlcNAc Transferase) to O-GlcNAcylate proteins, is also activated. O-GlcNAcylation is a dynamic post translational modification (PTM) that controlled a plethora of protein properties. Disturbance in the O-GlcNAcylation dynamism is implicated in several pathologies. Numerous studies link metabolic disorders emergence to O-GlcNAcylation mechanisms deregulation. Knowing that there is a close relationship between glucose, O-GlcNAcylation levels and activation of the glucido-lipid metabolism, a link between the activation of the glycolytic and the lipogenic enzymes and O-GlcNAcylation should exist. More precisely we focused on Fatty Acid Synthase, FAS which produces fatty acids. In this study, O-GlcNAcylation levels and FAS expression were analyzed in liver of C57BL6 mice fed a Chow Diet (CD) or High Carbohydrate Diet (HCD), in liver of mice harboring an inhibition of OGA and in primary hepatocytes of mice cultured in different O-GlcNAcylation levels. Co-immunoprecipitation experiments showed that OGT and FAS interacted physically but this interaction did not lead to FAS O-GlcNAcylation. However, a correlation between FAS expression and O-GlcNAcylation level was shown and an increase of O-GlcNAcylation levels paralleled the protection of FAS against this degradation. Moreover FAS activity was increased in fasted HCD mice compared to fasted CD mice. Taken together, our results suggest that O-GlcNAcylation may represent indirectly a new regulation of FAS protein content and activity in liver under both physiological and physiopathological conditions.
Ivan U. Kouzel
University of Münster, Germany
Title: Glycosphingolipid-mediated interaction of shiga toxin with the human endothelium: status quo of receptor research
Time : 14:15-14:35
Biography:
Dr. Ivan U. Kouzel has received his PhD in 2014 at the age of 28 years from the University of Münster. He is currently postdoctoral researcher in the group of Prof. Dr. Johannes Müthing, Institute for Hygiene, Münster, Germany, headed by Prof. Dr. Dr. h.c. Helge Karch. Ivan is involved in 5 publications in reputed journals, where he holds the first authorship in 2 publications.
Abstract:
Certain pathogenic Escherichia coli strains belong to the group of Shiga toxin (Stx)-producing E. coli (STEC), whereof the subgroup of enterohemorrhagic E. coli (EHEC) may cause epidemics like the 2011 European E. coli O104:H4 outbreak [1]. EHEC are implicated in a wide range of clinical complications in humans such as the potentially lethal hemolytic uremic syndrome (HUS). Once released from the gut into the blood circulation, Stxs are transported via highly debated mechanisms to the target endothelium with putative involvement of leukocytes and/or lipoproteins as delivery vehicles [2, 3]. Microvascular endothelial cells of human kidney and brain are the preferential targets [4, 5], injury of which is key in the development of HUS and damage of the blood-brain barrier [6]. Stxs specifically bind to the glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer), followed by internalization into the cell and eventual cell death. Lipid raft association of GSL receptors in the plasma membrane [5] is supposed to play a crucial role in binding, uptake, retrograde transport and cytotoxicity of Stxs. In this presentation the current knowledge on the molecular mechanisms of GSL-mediated interaction of Stxs with the human endothelium will be presented and discussed.
Cheorl-Ho Kim
SungKyunKwan University, Korea
Title: Cellular roles of ganglioside GM3 biosynthesis in human cancer cells
Time : 14:35-14:55
Biography:
Cheorl-Ho Kim has completed his Ph.D at the age of 28 years from The University of Tokyo and was positioned as a senior scientist from Korea Research Institute of Bioscience and Biotechnology. He is a professor of Molecular Glycobiology, SungKyunKwan University, Korea, leading organization of Korea, which is cooperated with the SamSung Group. He has published more than 337 papers in reputed journals and serving as an editorial board member, executive editor and editor-in chief of the international journals. His work was contributed to the mechanisms of glycan-mediated Hepatis B viral oncogenesis and invasion, sialoglycan-mediated leukemic differentiation and vascular biology. He is being serves as an Editor-in-Chief of Journal of Glycobiology, Editor-in-Chief of Journal of Microbial and Biochemical Technology, Executive Editor of Journal of Glycomics and Lipidomics and Editor of eCAM.
Abstract:
Ganglioside GM3, sialic acid (NeuAc)-containing glycosphingolipid, is the first and the simplest of the gangliosides and are found on the outer leaflet of the plasma membrane in vertebrates. It plays important roles in a large variety of biological processes, such as cellular interactions, differentiation, oncogenesis, adhesion, cell growth, and receptor function in various cell systems. Ganglioside GM3 is synthesized by lactosylceramide α-2,3-sialyltransferase (hST3Gal V, EC 2.4.99.9) which catalyzes the transfer of NeuAc from CMP-NeuAc to the non-reducing terminal galactose of lactosylceramide in human. The amount of ganglioside GM3 increases with a concomitant increase of hST3Gal V activity during megakaryocytic differentiation of K562 cells treated with PMA that is a megakaryocytic differentiation inducer, but not with an erythrocyte differentiation inducer, hemin. Ganglioside GM3 may play an important role as a trigger in differentiation induction of K562 cells. hST3Gal V is a key regulatory enzyme for ganglioside biosynthesis because it catalyzes the first committed step in the synthesis of nearly all gangliosides. Differentiation of K562 cells requires Erk1/2 activation and p38 MAPK inhibition for the transcriptional activity of lactosylceramide α-2,3-sialyltransferase (hST3Gal V) and synthesis of ganglioside GM3. The expression of hST3Gal V mRNA induces expression of the megakaryocytic markers and differentiation of K562 cells. Ganglioside GM3 mediates megakaryocytic differentiation of human chronic myelogenous cells and apoptosis of many human cancer cells.
Rune Thorbjørn Nordvang
Technical University of Denmark, Denmark
Title: A rational approach to identification of wild type trans-sialidases for the production of human milk oligosaccharides
Time : 14:55-15:15
Biography:
Rune Thorbjørn Nordvang is in the final stages of his PhD at the Technical University of Denmark (DTU). In the BioEng group (at DTU) he has worked with all aspects of enzymatic production of human milk oligo-saccharides from dairy side stream products and has published 6 articles on the topic.
Abstract:
In this study, sequence analysis and 3D alignment were used for the identification of a novel trans-sialidase, namely the trans-sialidase of Haemophilus parasuis. The H. parasuis trans-sialidase was one of four candidate enzymes selected from a database of 2909 protein sequences. It is the first time that a sequence analysis approach has been successful in identifying a trans-sialidase and additionally all remaining candidates (the sialidases of Pasteurella multosida, Actinomyces Oris and Manheimia Haemolytica) exhibited trans-activity, however they were ultimately not defined as trans-sialidases due to the comprehensive definition of a trans-silalidase. A trans-sialidase can be defined as a sialidase which, under a specific set of conditions, prefers the transfer of a sialic acid residue from a donor to an acceptor molecule over the hydrolysis of the donor. Trans-sialidases are sought after because they can be applied for the enzymatic production of human milk oligosaccharides (for addition to infant formula) from dairy side-stream products. So far, the only native trans-sialidase that has been found is the trans-sialidase of the human pathogen Trypanosomas cruzi. However, an additional trans-sialidase has been engineered through directed evolution of the sialidase of Trypanosomas rangeli. Rational inspection of the 3D structure of these known trans-sialidases was the basis for this study, and it is hoped that attributes of the newly identified H. parasuis trans-sialidase can be the basis of further trans-sialidase discovery.
Ivan Martinez Duncker
Cell Dynamics Research Center, MEXICO
Title: Sialobiology of T Cd4+ Cells
Time : 15:30-15:50
Biography:
Dr. Martinez Duncker is 37 years old and born in Mexico City. He earned his MD degree in the Military Medical School in Mexico after which he went to Paris, France to earn his PhD degree in the Ecole Pratique des Hautes Etudes. He is Director of the Cell Dynamics Research Center of the Morelos State Autonomous University in Cuernavaca, Mexico where he leads the Glycobiology and Human Genetics Program. He also is founder and President of the Latin American Society of Glycobiology.
Abstract:
T cells are probably one of the more dynamic models of cell glycosylation, particularly T CD4+ cells (Th). After activation and stimulation with specific cytokines, Th cells can differentiate into different subsets that include Th1, Th2, Th9, Th17 and T regulators (Treg), each one with different cytokine secretion profiles and effector functions. In the last few years it has been recognized that the presence and type of linkage in surface glycans of the negatively charged monosaccharide Sia, is different between this subsets and is involved in their distinct susceptibility to Galectin 1 mediated apoptosis. In this work we report the dynamics of sialylation during anti-CD3/anti-CD28 mediated activation of human CD4+ T helper lymphocytes (Th), including sialyltransferase gene expression changes and metabolic flux of sialic acid. The identification of novel sialoproteins and sialolipids through this approach sheds light into novel functions of sialic acids during Th activation.
Ezat Khosravi
Durham University, UK
Title: Functionalization and grafting of carbohydrates and synthesis of temperature responsive polymers
Biography:
Dr. Khosravi obtained his Ph.D. in polymer science from Sussex University, UK, 1982. He joined the polymer group at Chemistry Department, Durham University, UK, in 1987 where he is now a Reader in Polymer Chemistry. His research interests ranges from well-defined polymerisation chemistry to novel polymers and biopolymers. He has given 88 invited lectures worldwide, has been chairman in 16 international conferences, published 59 papers; has written 15 chapters for books, has edited 4 books and has filed 7 patent applications. He is an FRSC (Fellow of the Royal Society of Chemistry) and a member of the American Chemical Society.
Abstract:
The lecture describes a novel and versatile method for the modification of 2-hydroxyethyl cellulose (HEC) to prepare biocompatible and biodegradable materials to be used as personal products. The process of Click reactions involving azide-alkyne cycloaddition was used to impart neutral (ester) and ionic (carboxylic acid and 1ry amine) functionalities on HEC. Sequential Click reactions were also used to successfully synthesize polydimethylsiloxane (PDMS) grafted HEC containing neutral (ester) and ionic (carboxylic acid and 1ry amine) functionalities. Furthermore, The Click Coupling technique was utilized for grafting onto HEC; PLA (as hydrophobic segments) and PEG (as hydrophilic segments). The temperature responsive materials with low critical solution temperatures (LCST) in the physiological range (30-40 oC) attract much attention due to their potential biomedical and drug delivery applications. The lecture will also discuss the synthesis and characterization of a novel temperature responsive water-soluble glycopolymer based on trehalose via copper wire-catalyzed click-polymerization. The investigation of the cloud point of the aqueous solution of glycopolymer by optical microscopy and UV-Vis spectroscopy will also be discussed. The LCST of the glycopolymer was found to be within physiological range of about 39 oC, known as fever temperature. The full characterization of all the products as well as the intermediates by NMR, MS, IR, SEC, TGA and DSC will be presented.
Claudia Koch-Brandt
J.-Gutenberg-University, Germany
Title: Clusterin/ApoJ - How glycosylation modulates the function of this apolipoprotein
Biography:
Having worked in 1977/78 as a guest investigator in G. Blobel’s laboratory at Rockefeller University, New York, Dr. Koch-Brandt completed her PhD in 1980 from the Goethe University Frankfurt/Main, Germany. After five years as postdoc and staff scientist at the EMBL, Heidelberg, she became assistant professor at the Goethe–University and in 1991 full professor at Mainz University. She has been serving as acting department director and reviewer for international journals and science funding organisations. In 1984 she received the Heinz-Maier-Leibnitz-Award of the German Research Foundation, in 1998 she was the German nominee for the UNESCO-L’Oréal- then Women in Science-Award).
Abstract:
Clusterin (CLU), also known as ApolipoproteinJ (ApoJ) is a highly glycosylated extracellular chaperone. In humans it is expressed in a broad spectrum of tissues and related to a plethora of pathophysiological processes, such as M. Alzheimer, atherosclerosis and cancer, where the protein exerts a cytoprotective role. In its dominant form it is expressed as a secretory protein (sCLU) which during maturation is N-glycosylated and cleaved intracellularly into an α- and a β-chain connected by five symmetrical disulfide bonds. In early studies we examined the role of the carbohydrate moieties in the vectorial secretion of ApoJ at the apical surface of polarized epithelial cells. If N-glycosylation is inhibited by tunicamycin treatment the protein is secreted in equal amounts at both cell surfaces, demonstrating that the carbohydrates are dispensible for the acquisition of a transport competent conformation, however indicating a role of the carbohydrate moieties in the vectorial transport of this protein. Recently, it has been demonstrated that besides the predominant sCLU, rare intracellular CLU forms are expressed in stressed cells. Since these isoforms do not enter nor complete the secretory pathway, they display either no or only core glycosylation and are not proteolytically processed. Due to their sparsity, these intracellular forms are functionally poorly characterized. To evaluate the function(s) of these stress-induced intracellular forms, we first examined whether these isoforms display chaperone activity, to then investigate the impact of glycosylation and proteolytic maturation on this activity.
William L Holland
The University of Texas Southwestern Medical Center, USA
Title: Ceramides and glucosylceramides in diabetes
Biography:
Will Holland completed his dissertation work with Scott Summers at the University of Utah in 2007. Together, they produced seminal work establishing the role of ceramide in insulin resistance. During his subsequent postdoctoral work with Philipp Scherer, he uncovered the roles of adiponectin and FGF21 as potent regulators of sphingolipid metabolism. He is currently an Assistant Professor in the Touchstone Diabetes Center, focusing efforts on the roles of ceramide catabolic enzymes on glucose and lipid metabolism.
Abstract:
Insulin promotes the uptake and storage of carbohydrates, as well as other nutrients in skeletal muscle and adipose. It simultaneously represses secretion of glucagon (insulin’s counter-regulatory hormone) and subsequent glucose efflux from the liver. The hepatic glucose production stimulated by glucagon has been thought to play a significant role in the development of hyperglycemia. Just as insulin insufficiency can lead to elevated glucagon secretion, impaired insulin and leptin actions upon the alpha cell can also promote hyperglucagonemia and hyperglycemia. Sphingolipids, such as ceramides and glucosylceramides, are important bioactive lipid metabolites which can impair Akt-mediated signal transduction. We have demonstrated that ceramide is sufficient to impair insulin-induced suppression of glucagon from cultured glucagon-producing alpha-cells. Here, we elucidate the role of sphingolipid accumulation in aberrant glucagon production in vivo, we have used novel mouse models to drive expression of acid ceramidase under the control of a pre-proglucagon promoter. The local overexpression of acid ceramidase within the alpha cell is sufficient to improve insulin- or leptin-mediated Akt signaling within the alpha cell and prevent aberrant glucagon production. Induction of the acid ceramidase transgene is sufficient to reverse hyperglycemia within 48 hours in type 2 diabetic mice. Moreover, it is sufficient to prevent the onset of diabetes in ob/ob mice. Similarly, inducing the cre-lox mediated excision of glucosylceramide synthase within the alpha cell reverses glucagon overproduction and restores glycemia. Collectively, these data suggest that aberrant accumulation of ceramides or glucosylceramides within the alpha cell may be a causal link between insulin resistance and frank diabetes.
Biography:
Dr. Samira has completed his PhD at the age of 28 years from University of Malaya (151 in the world university ranking) and postdoctoral studies from University of Malaya, Nanotechnology & Catalysis Research Centre (NANOCAT). Her main research interests are in the areas of carbon nanomaterials, such as carbon nanotubes, graphene oxide and graphene nanosheets, metal oxide nanocomposites advance smart nanohybrids, especially apply in electrochemical sensors, supercapacitors, fuel cells and biomedical. She has published more than 45 papers in reputed journals and has been serving as an editorial board member of repute.
Abstract:
Carbohydrates are the main component of the extracellular matrix (ECM) where they associate with proteins to form glycoproteins or proteoglycans, or exist as long-chain dis-accharides. All ECM proteins except elastin have associated sugar, and, in some cases, ECM proteins require proper glycosylation to achieve the full biological activity. It is also now clear that many ECM proteins have carbohydrate-binding domains that specifically recognize and interact with glycoconjugates with other matrix components and on the cell surface. Carbohydrates have been implicated in a wide variety of processes, ranging from cell adhesion and migration to matrix assembly, growth factor sequestration and regulation, involvement in many aspects of immune function, binding of plasma proteins, and control of thrombogenesis. This contribution is a method of immobilizing and processing functional multi-component structures of the ECM, comprising the following successive process steps, including covalent binding of an adhesion promoter layer to cell culture carriers; culturing cells of a desired type on the adhesion promoter layer and thus immobilizing the ECM secreted by the cells by secretion and binding to the adhesion promoter layer; and application of a de-cellurization protocol so as to detach matrix-secreting cells from the surface while simultaneously retaining the structure and functionality of the immobilized ECM, which is connected to the adhesion promoter.
E. Ada Cavalcanti-Adam
University of Heidelberg, Germany
Title: Cell-matrix interactions at the nanoscale
Biography:
E. Ada Cavalcanti-Adam has completed her PhD in Biology from University of Heidelberg (Germany) and postdoctoral training at the Max Planck Institute for Metals Research in Stuttgart. She is research group leader at the University of Heidelberg Institute of Physical Chemistry and head of the Central Scientific Facility “Biomaterials and Molecular Biology†at the Max Planck of Intelligent Systems. She is also visiting Professor at the University of Pennsylvania. In recognition of her work she has received a number of awards, most notably the UNESCO-L’Orèal Prize “for women in scienceâ€.
Abstract:
In tissues of mesenchymal origin, cell-extracellular matrix interactions are necessary for adhesion and migration and rely on the assembly of focal adhesions, micrometer-sized structures comprising transmembrane and intracellular protein clusters. Over the past two decades these structures have been extensively studied to elucidate their organization, assembly, and molecular composition, as well as to determine their functional role. Synthetic materials decorated with biological molecules, such as adhesive molecules and growth factors, are widely used to mimic the extracellular environment and to induce specific cellular responses dependent on cell adhesion. Nanotechnology provides tools to mimic and investigate such responses at single molecule resolution. This lecture focuses on cell interactions with nanopatterned surfaces biofunctionalized with adhesive peptides recognized by integrins, as well as on surfaces decorated with bone morphogenetic protein 2. Results on cell adhesion and adhesion-mediated signaling induced by surface immobilization and spatial distribution of the ligands will be presented. Surface patterning strategies for presenting on the same platform different chemical cues of the extracellular space will be also discussed.
Regina Célia Teixeira Gomes
Federal University of São Paulo, Brazil
Title: Metoclopramide-induced hyperprolactinemia changed on murine uterine
Biography:
Gomes, RCT. has completed his PhD at the age of 42 years from Federal University of Sao Paulo, Brazil and postdoctoral studies from the same University. Since 2004 performs experimental research with hyperprolactinemia. Currently receives scholarship by the Foundation for Research Support of the State of São Paulo - FAPESP. Published several articles related to hyperprolactinemia and extracellular matrix.
Abstract:
Initially our group found out that the metoclopramide-induced hyperprolactinemia may negatively affect the endometrial morphology. And, in later studies we found out that the hyperprolactinemia caused a decrease in pinopode numbers and embryo implantation in female mice, thus interfering with the fertility and in ovarian function. In order to show the effectiveness of treatment with 200 µg metoclopramide for 50 consecutive days, we measured the serum prolactin levels and also analyzed the pituitary of animals. We proved that the hyperprolactinemia caused by metoclopramide in mice is due to an increase in the number and activity of lactotrophs. The deepening of the research led us to several questions. What are the biochemical changes that were occurring in the endometrial stroma (cells and extracellular matrix) of these animals? Finally, our results showed that the elevation of prolactin may lead to changes in the amounts of glycosaminoglycans, which are important for embryo implantation, in an animal model of hyperprolactinemia accompanied by a regular estrous cycle. Recently, we have researched the gene expression of small leucine-rich proteoglycans (SLRPs) on the murine uterus non pregnant and pregnant with hyperprolactinemia induced metoclopramide. The interactions between the production and degradation of these substances with steroids and hyperprolactinemia is complex and difficult to explain, because the signaling pathways involving those hormones may influence the cell-cell and cell-extracellular matrix interactions in the endometrial stroma, as well as they may interfere with the appropriate preparation of the endometrium to receive the embryo.