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Hans-joachim Gabius - One of the best experts on this subject based on the ideXlab platform.
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glycobiology of developing chicken kidney profiling the Galectin family and selected β galactosides
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2020Co-Authors: Joachim C Manning, Herbert Kaltner, Fred Sinowatz, Gabriel Garcia Caballero, Annakristin Ludwig, Hans-joachim GabiusAbstract:The concept of the sugar code interprets the cellular glycophenotype as a rich source of information read by glycan-lectin recognition in situ. This study's aim is the comprehensive characterization of Galectin expression by immunohistochemistry during chicken nephrogenesis along with mapping binding sites by (ga)lectin histochemistry. Light and two-color fluorescence microscopy were used. First, six plant/fungal lectins that are specific for Galectin-binding parts of N- and O-glycans were applied. The spatiotemporally regulated distributions of these glycans in meso- and metanephros equip cells with potential binding partners for the Galectins. Complete Galectin profiling from HH Stage 20 (about 70-72 hr) onward revealed cell-, Galectin-, and stage-dependent expression patterns. Representatives of all three types of modular architecture of the Galectin family are detectable, and overlaps of signal distribution in light and two-color fluorescence microscopy illustrate a possibility for functional cooperation among them. Performing systematic Galectin histochemistry facilitated comparisons between staining profiles of plant lectins and Galectins. They revealed several cases for differences so that tissue lectins appear to be selective among the β-galactosides. Notably, selectivity is also disclosed in intrafamily comparison. Thus, combining experimental series with plant and tissue lectins is a means to characterize target populations of glycans presented by cellular glycoconjugates for individual Galectins. Our results document the presence and sophisticated level of elaboration among β-galactosides and among the members of the family of Galectins during organogenesis, using chicken Galectins and kidney as model. Thus, they provide a clear guideline for functional assays using supramolecular tools, cells, and organ cultures.
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Galectin-8 induces functional disease markers in human osteoarthritis and cooperates with Galectins-1 and -3.
Cellular and molecular life sciences : CMLS, 2018Co-Authors: Daniela Weinmann, Michael Kenn, Sebastian Schmidt, Katy Schmidt, Sonja M. Walzer, Bernd Kubista, Reinhard Windhager, Wolfgang Schreiner, Stefan Toegel, Hans-joachim GabiusAbstract:The reading of glycan-encoded signals by tissue lectins is considered a major route of the flow of biological information in many (patho)physiological processes. The arising challenge for current research is to proceed from work on a distinct protein to family-wide testing of lectin function. Having previously identified homodimeric Galectin-1 and chimera-type Galectin-3 as molecular switches in osteoarthritis progression, we here provide proof-of-principle evidence for an intra-network cooperation of Galectins with three types of modular architecture. We show that the presence of tandem-repeat-type Galectin-8 significantly correlated with cartilage degeneration and that it is secreted by osteoarthritic chondrocytes. Glycan-inhibitable surface binding of Galectin-8 to these cells increased gene transcription and the secretion of functional disease markers. The natural variant Galectin-8 (F19Y) was less active than the prevalent form. Genome-wide array analysis revealed induction of a pro-degradative/inflammatory gene signature, largely under control of NF-κB signaling. This signature overlapped with respective gene-expression patterns elicited by Galectins-1 and -3, but also presented supplementary features. Functional assays with mixtures of Galectins that mimic the pathophysiological status unveiled cooperation between the three Galectins. Our findings shape the novel concept to consider individual Galectins as part of a so far not realized teamwork in osteoarthritis pathogenesis, with relevance beyond this disease.
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human osteoarthritic knee cartilage fingerprinting of adhesion growth regulatory Galectins in vitro and in situ indicates differential upregulation in severe degeneration
Histochemistry and Cell Biology, 2014Co-Authors: Stefan Toegel, Sonja M. Walzer, Reinhard Windhager, Sabine Andre, Daniela Bieder, Klaus Kayser, Gerhard M Hobusch, Hans-joachim GabiusAbstract:The apparent connection of Galectin-3 to chondrocyte survival and osteoarthritis-like cartilage modifications in animal models provided incentive for the mapping of seven members of this family of adhesion/growth-regulatory proteins in human cartilage specimens. Starting with work in vitro, RT-qPCR analyses and immunocytochemistry revealed gene transcription and protein presence in cultured OA chondrocytes, especially for Galectin-1, Galectin-3 and Galectin-8. Immunohistochemistry in clinical specimens with mild and severe cartilage degeneration detected Galectins in chondrocytes-with upregulation, especially of Galectin-1 in areas of severe degeneration-accompanied by α2,6-sialylation in the pericellular matrix. Given the possibility for additive/antagonistic activities between Galectins, these results direct further research toward examining cellular effects of (1) these proteins (alone or in combination) on chondrocytes and (2) remodeling of the chondrocyte glycophenotype.
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bi to tetravalent glycoclusters synthesis structure activity profiles as lectin inhibitors and impact of combining both valency and headgroup tailoring on selectivity
Organic and Biomolecular Chemistry, 2012Co-Authors: Guannan Wang, Hans-joachim Gabius, Sabine Andre, Paul V MurphyAbstract:The emerging functional versatility of cellular glycans makes research on the design of synthetic inhibitors a timely topic. In detail, the combination of ligand (or headgroup or contact site) structure with spatial parameters that depend on topological and geometrical factors underlies the physiological selectivity of glycan-protein (lectin) recognition. We herein tested a panel of bi-, tri- and tetravalent compounds against two plant agglutinins and adhesion/growth-regulatory lectins (Galectins). In addition, we examined the impact of headgroup tailoring (converting lactose to 2'-fucosyllactose) in combination with valency increase in two assay types of increasing biorelevance (from solid-phase binding to cell binding). Compounds were prepared using copper-catalysed azide alkyne cycloaddition from peracetylated lactosyl or 2'-fucosyllactosyl azides. Significant inhibition was achieved for the plant toxin with a tetravalent compound. Different levels of sensitivity were noted for the three groups of the Galectin family. The headgroup extension to 2'-fucosyllactose led to a selectivity gain, especially for the chimera-type Galectin-3. Valency increase established discrimination against the homodimeric proteins, whereas the combination of valency with the headgroup extension led to discrimination against the tandem-repeat-type Galectin-8 for chicken Galectins but not human Galectins-3 and -4. Thus, detailed structure-activity profiling of glycoclusters combined with suitably modifying the contact site for the targeted lectin will help minimize cross-reactivity among this class of closely related proteins.
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Galectin 8 up regulation during hypopharyngeal and laryngeal tumor progression and comparison with Galectin 1 3 and 7
Anticancer Research, 2009Co-Authors: Stéphanie Cludts, Hans-joachim Gabius, Herbert Kaltner, Sabine Andre, Christine Decaestecker, Virginie Mahillon, Dominique Chevalier, Myriam Remmelink, Xavier Leroy, Sven SaussezAbstract:Aim: To define specific staining patterns for the adhesion/growth-regulatory lectin tandem-repeat-type Galectin-8 in hypopharyngeal and laryngeal tumor progression and relate these parameters to Galectins 1, 3 and 7 in the quest to explore the Galectin network. Materials and Methods: The level of expression of Galectin-8 was determined immunohistochemically in a series of 18 and 16 cases of tumor-free epithelium, 24 and 10 cases of low- grade dysplasia, 22 and 15 cases of high-grade dysplasia located in peri-tumoral area of 74 and 37 hypopharyngeal and laryngeal carcinomas. Results: Marked upregulation in Galectin-8 staining intensity and immunopositive area in malignancy versus dysplasia was seen in hypopharyngeal cancer (p<10 -6 ), in laryngeal cancer for labeling index and high-grade dysplasia/carcinoma (p<10 -6 ). No correlation to
Hakon Leffler - One of the best experts on this subject based on the ideXlab platform.
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C1-Galactopyranosyl Heterocycle Structure Guides Selectivity: Triazoles Prefer Galectin‑1 and Oxazoles Prefer Galectin‑3
2019Co-Authors: Alexander Dahlqvist, Hakon Leffler, Ulf J NilssonAbstract:Galectins are carbohydrate-recognizing proteins involved in many different pathological processes, including cancer and immune-related disorders. Inhibitors of Galectins have evolved from natural oligosaccharides toward more drug-like truncated galactoside scaffolds that only retain key specific interactions of the galactose scaffolds with the Galectin carbohydrate recognition domains. In this context, C1-galactosides are attractive and stable scaffolds, and this work reports that the synthesis of novel C1-galactopyranosyl heteroaryl derivatives as Galectin inhibitors, in which Galectin selectivity is governed by the composition of the heterocycle and affinity, is driven by the structure of the aryl substituent to give compounds selective for either Galectin-1 or Galectin-3. The affinities are close to or better than those of lactose and other natural Galectin-binding disaccharides, selectivities induced by the C1-heteroaryl groups are superior to lactose, and compound hydrolytic stabilities and drug-like properties are potentially better than those of natural saccharides. Hence, C1-galactopyranosyl heteroaryls constitute a class of promising starting scaffolds for Galectin inhibition, in which a natural ligand pyranose has been replaced by more than fivefold selectivity-inducing heteroaryl rings leading to affinities of 90 μM toward Galectin-3 for a C1-galactopyranosyl naphthyloxazole and 170 μM toward Galectin-1 for a C1-galactopyranosyl 2-fluorophenyltriazole
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glycoproteomic identification of Galectin 3 and 8 ligands in bronchoalveolar lavage of mild asthmatics and healthy subjects
Biochimica et Biophysica Acta, 2012Co-Authors: Cecilia Cederfur, Mattias Block, Michael E. Breimer, Johan Malmstrom, Kristian Nihlberg, Leif Bjermer, Gunilla Westergrenthorsson, Hakon LefflerAbstract:Abstract Background Galectins, a family of small carbohydrate binding proteins, have been implicated in regulation of inflammatory reactions, including asthma and fibrosis in the lungs. Galectins are found in cells of the airways and in airway secretions, but their glycoprotein ligands there have only been studied to a very limited extent. Methods Bronchoalveolar lavage (BAL) fluid from mild asthmatics and healthy volunteers were fractionated by affinity chromatography on the immobilized Galectins. Total (10–30 μg) and Galectin bound (~ 1–10 μg) protein fractions were identified, quantified and compared using shot-gun proteomics and spectral counts. Results About 175 proteins were identified in unfractionated BAL-fluid, and about 100 bound Galectin-3 and 60 bound Galectin-8. These included plasma glycoproteins, and typical airway proteins such as SP-A2, PIGR and SP-B. The concentration of Galectin-binding proteins was 100–300 times higher than the concentration of Galectins in BAL. Conclusion The low relative concentration of Galectins in BAL makes it likely that functional interactions with glycoproteins occur at sites rich in Galectin, such as cells of the airways, rather than the extracellular fluid itself. The profile of Galectin bound proteins differed between samples from asthma patients and healthy subjects and correlated with the presence of fibroblasts or eosinophils. This included appearance of a specific Galectin-8-binding glycoform of haptoglobin, previously shown to be increased in serum in other inflammatory conditions. General significance It is technically feasible to identify Galectin-binding glycoproteins in low concentration patient samples such as BAL-fluid, to generate biomedically interesting results. This article is part of a Special Issue entitled Glycoproteomics.
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Galectin-3, a marker for vacuole lysis by invasive pathogens.
Cellular Microbiology, 2010Co-Authors: Irit Paz, Hakon Leffler, Martin Sachse, Nicolas Dupont, Joelle Mounier, Cecilia Cederfur, Jost Enninga, Francoise Poirier, Marie-christine Prevost, Frank LafontAbstract:Shigella bacteria invade macrophages and epithelial cells and following internalization lyse the phagosome and escape to the cytoplasm. Galectin-3, an abundant protein in macrophages and epithelial cells, belongs to a family of beta-galactoside-binding proteins, the Galectins, with many proposed functions in immune response, development, differentiation, cancer and infection. Galectins are synthesized as cytosolic proteins and following non-classical secretion bind extracellular beta-galactosides. Here we analysed the localization of Galectin-3 following entry of Shigella into the cytosol and detected a striking phenomenon. Very shortly after bacterial invasion, intracellular Galectin-3 accumulated in structures in vicinity to internalized bacteria. By using immuno-electron microscopy analysis we identified Galectin-3 in membranes localized in the phagosome and in tubules and vesicles that derive from the endocytic pathway. We also demonstrated that the binding of Galectin-3 to host N-acetyllactosamine-containing glycans, was required for forming the structures. Accumulation of the structures was a type three secretion system-dependent process. More specifically, existence of structures was strictly dependent upon lysis of the phagocytic vacuole and could be shown also by Gram-positive Listeria and Salmonella sifA mutant. We suggest that Galectin-3-containing structures may serve as a potential novel tool to spot vacuole lysis.
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different affinity of Galectins for human serum glycoproteins Galectin 3 binds many protease inhibitors and acute phase proteins
Glycobiology, 2008Co-Authors: Cecilia Cederfur, Ulf J Nilsson, Christopher T. Öberg, Emma Salomonsson, Jonas Nilsson, Adnan Halim, Goran Larson, Hakon LefflerAbstract:Here we report the first survey of Galectins binding to glycoproteins of human serum. Serum was subjected to affinity chromatography using immobilized Galectins, and the bound glycoproteins were analyzed by electrophoresis, Western blotting, and mass spectrometry. Galectins-3, -8, and -9 bound a much broader range of ligands in serum than previously known, Galectin-1 bound less, and Galectins-2, -4, and -7 bound only traces or no serum ligands. Galectin-3 bound most major glycoproteins, including alpha-2-macroglobulin and acute phase proteins such as haptoglobin. It bound only a selected minor fraction of transferrin, and bound none or little of IgG. Galectins-8 and -9 bound a similar range of glycoproteins as Galectin-3, but in lower amounts, and Galectin-8 had a relative preference for IgA. Galectin-1 bound mainly a fraction of alpha-2-macroglobulin and only traces of other glycoproteins. The binding of Galectin-3 to serum glycoproteins requires affinity for LacNAc, since a mutant (R186S), which has lost this affinity, did not bind any serum glycoproteins. The average affinity of Galectin-3 for serum glycoproteins was estimated to correspond to K(d) approximately 1-5 muM by modeling of the affinity chromatography and a fluorescence anisotropy assay. Since Galectins are expressed on endothelial cells and other cells exposed to serum components, this report gives new insight into function of Galectins and the role of their different fine specificity giving differential binding to the serum glycoproteins.
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Galectin 1 2 and 3 exhibit differential recognition of sialylated glycans and blood group antigens
Journal of Biological Chemistry, 2008Co-Authors: Sean R Stowell, David F Smith, Hakon Leffler, Connie M Arthur, Padmaja Mehta, Kristen A Slanina, Ola Blixt, Richard D. CummingsAbstract:Human Galectins have functionally divergent roles, although most of the members of the Galectin family bind weakly to the simple disaccharide lactose (Galbeta1-4Glc). To assess the specificity of Galectin-glycan interactions in more detail, we explored the binding of several important Galectins (Gal-1, Gal-2, and Gal-3) using a dose-response approach toward a glycan microarray containing hundreds of structurally diverse glycans, and we compared these results to binding determinants on cells. All three Galectins exhibited differences in glycan binding characteristics. On both the microarray and on cells, Gal-2 and Gal-3 exhibited higher binding than Gal-1 to fucose-containing A and B blood group antigens. Gal-2 exhibited significantly reduced binding to all sialylated glycans, whereas Gal-1 bound alpha2-3- but not alpha2-6-sialylated glycans, and Gal-3 bound to some glycans terminating in either alpha2-3- or alpha2-6-sialic acid. The effects of sialylation on Gal-1, Gal-2, and Gal-3 binding to cells also reflected differences in cellular sensitivity to Gal-1-, Gal-2-, and Gal-3-induced phosphatidylserine exposure. Each Galectin exhibited higher binding for glycans with poly-N-acetyllactosamine (poly(LacNAc)) sequences (Galbeta1-4GlcNAc)(n) when compared with N-acetyllactosamine (LacNAc) glycans (Galbeta1-4GlcNAc). However, only Gal-3 bound internal LacNAc within poly(LacNAc). These results demonstrate that each of these Galectins mechanistically differ in their binding to glycans on the microarrays and that these differences are reflected in the determinants required for cell binding and signaling. The specific glycan recognition by each Galectin underscores the basis for differences in their biological activities.
Ulf J Nilsson - One of the best experts on this subject based on the ideXlab platform.
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C1-Galactopyranosyl Heterocycle Structure Guides Selectivity: Triazoles Prefer Galectin‑1 and Oxazoles Prefer Galectin‑3
2019Co-Authors: Alexander Dahlqvist, Hakon Leffler, Ulf J NilssonAbstract:Galectins are carbohydrate-recognizing proteins involved in many different pathological processes, including cancer and immune-related disorders. Inhibitors of Galectins have evolved from natural oligosaccharides toward more drug-like truncated galactoside scaffolds that only retain key specific interactions of the galactose scaffolds with the Galectin carbohydrate recognition domains. In this context, C1-galactosides are attractive and stable scaffolds, and this work reports that the synthesis of novel C1-galactopyranosyl heteroaryl derivatives as Galectin inhibitors, in which Galectin selectivity is governed by the composition of the heterocycle and affinity, is driven by the structure of the aryl substituent to give compounds selective for either Galectin-1 or Galectin-3. The affinities are close to or better than those of lactose and other natural Galectin-binding disaccharides, selectivities induced by the C1-heteroaryl groups are superior to lactose, and compound hydrolytic stabilities and drug-like properties are potentially better than those of natural saccharides. Hence, C1-galactopyranosyl heteroaryls constitute a class of promising starting scaffolds for Galectin inhibition, in which a natural ligand pyranose has been replaced by more than fivefold selectivity-inducing heteroaryl rings leading to affinities of 90 μM toward Galectin-3 for a C1-galactopyranosyl naphthyloxazole and 170 μM toward Galectin-1 for a C1-galactopyranosyl 2-fluorophenyltriazole
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Galectin binding to cells and glycoproteins with genetically modified glycosylation reveals Galectin glycan specificities in a natural context
Journal of Biological Chemistry, 2018Co-Authors: Mathias Nielsen, Ulf J Nilsson, John Stegmayr, Oliver C Grant, Zhang Yang, Irene Boos, Michael C Carlsson, Robert J Woods, Carlo UnverzagtAbstract:Galectins compose a protein family defined by a conserved sequence motif conferring affinity for β-galactose–containing glycans. Moreover, Galectins gain higher affinity and fine-tune specificity by glycan interactions at sites adjacent to their β-galactoside–binding site, as revealed by extensive testing against panels of purified glycans. However, in cells, Galectins bind glycans on glycoproteins and glycolipids in the context of other cellular components, such as at the cell surface. Because of difficulties in characterizing natural cellular environments, we currently lack a detailed understanding of Galectin-binding specificities in the cellular context. To address this challenge, we used a panel of genetically stable glycosylation mutated CHO cells that express defined glycans to evaluate the binding affinities of 10 different carbohydrate-recognition domains in Galectins to N-glycans and mucin-type O-glycans. Using flow cytometry, we measured the cell-surface binding of the Galectins. Moreover, we used fluorescence anisotropy to determine the Galectin affinities to recombinant erythropoietin used as a reporter glycoprotein produced by the glycoengineered cells and to synthetic N-glycans with defined branch structures. We found that all Galectins, apart from Galectin-8N, require complex N-glycans for high-affinity binding. Galectin-8N targeted both N- and O-linked glycans with high affinity, preferring 2,3-sialylated N-acetyllactosamine (LacNAc) structures. Furthermore, we found that 2,3-sialylation suppresses high-affinity binding of select Galectins, including Galectin-2, -3, -4N, and -7. Structural modeling provided a basis for interpreting the observed binding preferences. These results underscore the power of a glycoengineered platform to dissect the glycan-binding specificities of carbohydrate-binding proteins.
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Protein subtype-targeting through ligand epimerization: talose-selectivity of Galectin-4 and Galectin-8.
Bioorganic & medicinal chemistry letters, 2008Co-Authors: Christopher T. Öberg, Helen Blanchard, Ulf J NilssonAbstract:A series of O2 and O3-derivatized methyl beta-d-talopyranosides were synthesized and evaluated in vitro as inhibitors of the galactose-binding Galectin-1, -2, -3, -4 (N- and C-terminal domains), 8 (N-terminal domain), and 9 (N-terminal domain). Galectin-4C and 8N were found to prefer the d-talopyranose configuration to the natural ligand d-galactopyranose configuration. Derivatization at talose O2 and/or O3 provided selective submillimolar inhibitors for these two Galectins.
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different affinity of Galectins for human serum glycoproteins Galectin 3 binds many protease inhibitors and acute phase proteins
Glycobiology, 2008Co-Authors: Cecilia Cederfur, Ulf J Nilsson, Christopher T. Öberg, Emma Salomonsson, Jonas Nilsson, Adnan Halim, Goran Larson, Hakon LefflerAbstract:Here we report the first survey of Galectins binding to glycoproteins of human serum. Serum was subjected to affinity chromatography using immobilized Galectins, and the bound glycoproteins were analyzed by electrophoresis, Western blotting, and mass spectrometry. Galectins-3, -8, and -9 bound a much broader range of ligands in serum than previously known, Galectin-1 bound less, and Galectins-2, -4, and -7 bound only traces or no serum ligands. Galectin-3 bound most major glycoproteins, including alpha-2-macroglobulin and acute phase proteins such as haptoglobin. It bound only a selected minor fraction of transferrin, and bound none or little of IgG. Galectins-8 and -9 bound a similar range of glycoproteins as Galectin-3, but in lower amounts, and Galectin-8 had a relative preference for IgA. Galectin-1 bound mainly a fraction of alpha-2-macroglobulin and only traces of other glycoproteins. The binding of Galectin-3 to serum glycoproteins requires affinity for LacNAc, since a mutant (R186S), which has lost this affinity, did not bind any serum glycoproteins. The average affinity of Galectin-3 for serum glycoproteins was estimated to correspond to K(d) approximately 1-5 muM by modeling of the affinity chromatography and a fluorescence anisotropy assay. Since Galectins are expressed on endothelial cells and other cells exposed to serum components, this report gives new insight into function of Galectins and the role of their different fine specificity giving differential binding to the serum glycoproteins.
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synthesis of a phenyl thio d galactopyranoside library from 1 5 difluoro 2 4 dinitrobenzene discovery of efficient and selective monosaccharide inhibitors of Galectin 7
Organic and Biomolecular Chemistry, 2005Co-Authors: Ian Cumpstey, Hakon Leffler, Susanne Carlsson, Ulf J NilssonAbstract:The Galectins are a family of β-galactoside-binding proteins that have been implicated in cancer and inflammation processes. Herein, we report the synthesis of a library of 28 compounds that was tested for binding to Galectins-1, -3, -7, -8N and -9N. An aromatic nucleophilic substitution reaction between 1,5-difluoro-2,4-dinitrobenzene and a galacto thiol gave 5-fluoro-2,4-dinitrophenyl 2,3,4,6-tetra-O-acetyl-1-thio-β-D-galactopyranoside. This versatile intermediate was then modified in a two dimensional manner: either by further substitution of the second fluoride by amines or thiols, or by reduction of the nitro groups and acylation of the resulting amines, or both. Deacetylation then gave a library of aromatic β-galactosides that showed variable inhibitory activity against the different Galectins, as shown by screening with a fluorescence-polarisation assay. Particularly efficient inhibitors were found against Galectin-7, while less impressive enhancements of inhibitor affinity over methyl β-D-galactopyranoside were found for Galectin-1, -3, -8N and -9N. The best inhibitors against Galectin-7 showed significantly higher affinity (Kd as low as 140 µM) than both β-methyl galactoside (Kd 4.8 mM) and the unsubstituted β-phenyl thiogalactoside (non-inhibitory). The best inhibitors against Galectin-7 were poor against the other Galectins and thus have potential as structurally simple and selective tools for dissecting biological functions of Galectin-7.
Sabine Andre - One of the best experts on this subject based on the ideXlab platform.
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comparative lectinology delineating glycan specificity profiles of the chicken Galectins using neoglycoconjugates in a cell assay
Glycobiology, 2015Co-Authors: Eugenia M Rapoport, Herbert Kaltner, Sabine Andre, Galina V Pazynina, Vyacheslav V Severov, Varvara K Matveeva, Olga A Vokhmyanina, Ivan M Ryzhov, Elena Korchagina, Ivan M BelyanchikovAbstract:A major aspect of carbohydrate-dependent Galectin functionality is their cross-linking capacity. Using a cell surface as biorelevant platform for Galectin binding and a panel of 40 glycans as sensor part of a fluorescent polyacrylamide neoglycopolymer for profiling Galectin reactivity, properties of related proteins can be comparatively analyzed. The group of the chicken Galectins (CGs) is an especially suited system toward this end due to its relatively small size, compared with mammalian Galectins. The experiments reveal particularly strong reactivity toward N-acetyllactosamine repeats for all tested CGs and shared reactivity of CG-1A and CG-2 to histo-blood group ABH determinants. In cross-species comparison, CG-1B's properties closely resembled those of human Galectin-1, as was the case for the Galectin-2 (but not Galectin-3) ortholog pair. Although binding-site architectures are rather similar, reactivity patterns can well differ.
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human osteoarthritic knee cartilage fingerprinting of adhesion growth regulatory Galectins in vitro and in situ indicates differential upregulation in severe degeneration
Histochemistry and Cell Biology, 2014Co-Authors: Stefan Toegel, Sonja M. Walzer, Reinhard Windhager, Sabine Andre, Daniela Bieder, Klaus Kayser, Gerhard M Hobusch, Hans-joachim GabiusAbstract:The apparent connection of Galectin-3 to chondrocyte survival and osteoarthritis-like cartilage modifications in animal models provided incentive for the mapping of seven members of this family of adhesion/growth-regulatory proteins in human cartilage specimens. Starting with work in vitro, RT-qPCR analyses and immunocytochemistry revealed gene transcription and protein presence in cultured OA chondrocytes, especially for Galectin-1, Galectin-3 and Galectin-8. Immunohistochemistry in clinical specimens with mild and severe cartilage degeneration detected Galectins in chondrocytes-with upregulation, especially of Galectin-1 in areas of severe degeneration-accompanied by α2,6-sialylation in the pericellular matrix. Given the possibility for additive/antagonistic activities between Galectins, these results direct further research toward examining cellular effects of (1) these proteins (alone or in combination) on chondrocytes and (2) remodeling of the chondrocyte glycophenotype.
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expression of Galectins 1 3 and 9 in normal oral epithelium oral squamous papilloma and oral squamous cell carcinoma
Dental research journal, 2014Co-Authors: Thais Ayako Hossaka, Sabine Andre, Daniel Araki Ribeiro, Gustavo Rubino De Azevedo Focchi, Mariana Fernandes, Fernando Cintra Lopes Carapeto, Marcelo Souza Silva, Celina Tizuko Fujiyama OshimaAbstract:Back ground: The aim of this study was to characterize the immunohistochemical expression of Galectin 1, 3, and 9 in normal oral epithelium, oral squamous papilloma, and oral squamous cell carcinoma. Materials and Methods: Immunohistochemical staining for Galectins 1, 3, and 9 was evaluated in 8 samples of normal oral squamous epithelium, 15 samples of oral squamous papilloma, and 41 samples of oral squamous cell carcinoma. Immunohistochemical data were assessed by Kruskal- Wallis non-parametric test followed by Dunn’s test. For all analyzes, it was adopted the value of P <0.05 for statistical signifi cance. Results: Signifi cant differences were found in Galectin- 3 expression when comparing ordinary mucosa and oral squamous papilloma with the oral squamous cell carcinoma samples. Conclusion: These fi ndings indicate that Galectin-3 is closely involved in malignant transformation of oral mucosa cells. Key Words: Gale ctin-1, Galectin-3, Galectin-9, oral squamous cell carcinoma, oral squamous papilloma
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bi to tetravalent glycoclusters synthesis structure activity profiles as lectin inhibitors and impact of combining both valency and headgroup tailoring on selectivity
Organic and Biomolecular Chemistry, 2012Co-Authors: Guannan Wang, Hans-joachim Gabius, Sabine Andre, Paul V MurphyAbstract:The emerging functional versatility of cellular glycans makes research on the design of synthetic inhibitors a timely topic. In detail, the combination of ligand (or headgroup or contact site) structure with spatial parameters that depend on topological and geometrical factors underlies the physiological selectivity of glycan-protein (lectin) recognition. We herein tested a panel of bi-, tri- and tetravalent compounds against two plant agglutinins and adhesion/growth-regulatory lectins (Galectins). In addition, we examined the impact of headgroup tailoring (converting lactose to 2'-fucosyllactose) in combination with valency increase in two assay types of increasing biorelevance (from solid-phase binding to cell binding). Compounds were prepared using copper-catalysed azide alkyne cycloaddition from peracetylated lactosyl or 2'-fucosyllactosyl azides. Significant inhibition was achieved for the plant toxin with a tetravalent compound. Different levels of sensitivity were noted for the three groups of the Galectin family. The headgroup extension to 2'-fucosyllactose led to a selectivity gain, especially for the chimera-type Galectin-3. Valency increase established discrimination against the homodimeric proteins, whereas the combination of valency with the headgroup extension led to discrimination against the tandem-repeat-type Galectin-8 for chicken Galectins but not human Galectins-3 and -4. Thus, detailed structure-activity profiling of glycoclusters combined with suitably modifying the contact site for the targeted lectin will help minimize cross-reactivity among this class of closely related proteins.
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Galectin 8 up regulation during hypopharyngeal and laryngeal tumor progression and comparison with Galectin 1 3 and 7
Anticancer Research, 2009Co-Authors: Stéphanie Cludts, Hans-joachim Gabius, Herbert Kaltner, Sabine Andre, Christine Decaestecker, Virginie Mahillon, Dominique Chevalier, Myriam Remmelink, Xavier Leroy, Sven SaussezAbstract:Aim: To define specific staining patterns for the adhesion/growth-regulatory lectin tandem-repeat-type Galectin-8 in hypopharyngeal and laryngeal tumor progression and relate these parameters to Galectins 1, 3 and 7 in the quest to explore the Galectin network. Materials and Methods: The level of expression of Galectin-8 was determined immunohistochemically in a series of 18 and 16 cases of tumor-free epithelium, 24 and 10 cases of low- grade dysplasia, 22 and 15 cases of high-grade dysplasia located in peri-tumoral area of 74 and 37 hypopharyngeal and laryngeal carcinomas. Results: Marked upregulation in Galectin-8 staining intensity and immunopositive area in malignancy versus dysplasia was seen in hypopharyngeal cancer (p<10 -6 ), in laryngeal cancer for labeling index and high-grade dysplasia/carcinoma (p<10 -6 ). No correlation to
Herbert Kaltner - One of the best experts on this subject based on the ideXlab platform.
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glycobiology of developing chicken kidney profiling the Galectin family and selected β galactosides
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2020Co-Authors: Joachim C Manning, Herbert Kaltner, Fred Sinowatz, Gabriel Garcia Caballero, Annakristin Ludwig, Hans-joachim GabiusAbstract:The concept of the sugar code interprets the cellular glycophenotype as a rich source of information read by glycan-lectin recognition in situ. This study's aim is the comprehensive characterization of Galectin expression by immunohistochemistry during chicken nephrogenesis along with mapping binding sites by (ga)lectin histochemistry. Light and two-color fluorescence microscopy were used. First, six plant/fungal lectins that are specific for Galectin-binding parts of N- and O-glycans were applied. The spatiotemporally regulated distributions of these glycans in meso- and metanephros equip cells with potential binding partners for the Galectins. Complete Galectin profiling from HH Stage 20 (about 70-72 hr) onward revealed cell-, Galectin-, and stage-dependent expression patterns. Representatives of all three types of modular architecture of the Galectin family are detectable, and overlaps of signal distribution in light and two-color fluorescence microscopy illustrate a possibility for functional cooperation among them. Performing systematic Galectin histochemistry facilitated comparisons between staining profiles of plant lectins and Galectins. They revealed several cases for differences so that tissue lectins appear to be selective among the β-galactosides. Notably, selectivity is also disclosed in intrafamily comparison. Thus, combining experimental series with plant and tissue lectins is a means to characterize target populations of glycans presented by cellular glycoconjugates for individual Galectins. Our results document the presence and sophisticated level of elaboration among β-galactosides and among the members of the family of Galectins during organogenesis, using chicken Galectins and kidney as model. Thus, they provide a clear guideline for functional assays using supramolecular tools, cells, and organ cultures.
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how presence of a signal peptide affects human Galectins 1 and 4 clues to explain common absence of a leader sequence among adhesion growth regulatory Galectins
Biochimica et Biophysica Acta, 2020Co-Authors: Tanja J Kutzner, Herbert Kaltner, Jürgen Kopitz, Alonso M Higuero, Martina Susmair, Michael Hingar, Natalia Diezrevuelta, Gabriel Garcia Caballero, Ingo Lindner, Jose AbadrodriguezAbstract:Abstract Background Galectins are multifunctional effectors, which all share absence of a signal sequence. It is not clear why Galectins belong to the small set of proteins, which avoid the classical export route. Methods Products of recombinant Galectin expression in P. pastoris were analyzed by haemagglutination, gel filtration and electrophoresis and lectin blotting as well as mass spectrometry on the level of tryptic peptides and purified glycopeptides(s). Density gradient centrifugation and confocal laser scanning microscopy facilitated localization in transfected human and rat cells, proliferation assays determined activity as growth mediator. Results Directing Galectin-1 to the classical secretory pathway in yeast produces N-glycosylated protein that is active. It cofractionates and -localizes with calnexin in human cells, only Gal-4 is secreted. Presence of N-glycan(s) reduces affinity of cell binding and growth regulation by Gal-1. Conclusions Folding and activity of a Galectin are maintained in signal-peptide-directed routing, N-glycosylation occurs. This pathway would deplete cytoplasm and nucleus of Galectin, presence of N-glycans appears to interfere with lattice formation. General significance Availability of glycosylated Galectins facilitates functional assays to contribute to explain why Galectins invariably avoid classical routing for export.
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comparative lectinology delineating glycan specificity profiles of the chicken Galectins using neoglycoconjugates in a cell assay
Glycobiology, 2015Co-Authors: Eugenia M Rapoport, Herbert Kaltner, Sabine Andre, Galina V Pazynina, Vyacheslav V Severov, Varvara K Matveeva, Olga A Vokhmyanina, Ivan M Ryzhov, Elena Korchagina, Ivan M BelyanchikovAbstract:A major aspect of carbohydrate-dependent Galectin functionality is their cross-linking capacity. Using a cell surface as biorelevant platform for Galectin binding and a panel of 40 glycans as sensor part of a fluorescent polyacrylamide neoglycopolymer for profiling Galectin reactivity, properties of related proteins can be comparatively analyzed. The group of the chicken Galectins (CGs) is an especially suited system toward this end due to its relatively small size, compared with mammalian Galectins. The experiments reveal particularly strong reactivity toward N-acetyllactosamine repeats for all tested CGs and shared reactivity of CG-1A and CG-2 to histo-blood group ABH determinants. In cross-species comparison, CG-1B's properties closely resembled those of human Galectin-1, as was the case for the Galectin-2 (but not Galectin-3) ortholog pair. Although binding-site architectures are rather similar, reactivity patterns can well differ.
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Galectin 8 up regulation during hypopharyngeal and laryngeal tumor progression and comparison with Galectin 1 3 and 7
Anticancer Research, 2009Co-Authors: Stéphanie Cludts, Hans-joachim Gabius, Herbert Kaltner, Sabine Andre, Christine Decaestecker, Virginie Mahillon, Dominique Chevalier, Myriam Remmelink, Xavier Leroy, Sven SaussezAbstract:Aim: To define specific staining patterns for the adhesion/growth-regulatory lectin tandem-repeat-type Galectin-8 in hypopharyngeal and laryngeal tumor progression and relate these parameters to Galectins 1, 3 and 7 in the quest to explore the Galectin network. Materials and Methods: The level of expression of Galectin-8 was determined immunohistochemically in a series of 18 and 16 cases of tumor-free epithelium, 24 and 10 cases of low- grade dysplasia, 22 and 15 cases of high-grade dysplasia located in peri-tumoral area of 74 and 37 hypopharyngeal and laryngeal carcinomas. Results: Marked upregulation in Galectin-8 staining intensity and immunopositive area in malignancy versus dysplasia was seen in hypopharyngeal cancer (p<10 -6 ), in laryngeal cancer for labeling index and high-grade dysplasia/carcinoma (p<10 -6 ). No correlation to
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cell type specific expression of murine multifunctional Galectin 3 and its association with follicular atresia luteolysis in contrast to pro apoptotic Galectins 1 and 7
Histochemistry and Cell Biology, 2008Co-Authors: Michaela Lohr, Herbert Kaltner, Martin Lensch, Sabine Andre, Fred Sinowatz, Hans-joachim GabiusAbstract:Galectin-3 is a multifunctional protein with modular design. A distinct expression profile was determined in various murine organs when set into relation to homodimeric Galectins-1 and -7. Fittingly, the signature of putative transcription-factor-binding sites in the promoter region of the Galectin-3 gene affords a toolbox for a complex combinatorial regulation, distinct from the respective sequence stretches in Galectins-1 and -7. A striking example for cell-type specificity was the ovary, where these two lectins were confined to the surface epithelium. Immunohistochemically, Galectin-3 was found in macrophages of the cortical interstitium between developing follicles and medullary interstitium, matching the distribution of the F4/80 antigen. With respect to atresia and luteolysis strong signals in granulosa cells of atretic preantral but not antral follicles and increasing positivity in corpora lutea upon regression coincided with DNA fragmentation. Labeled Galectin-3 revealed lactose-inhibitable binding to granulosa cells. Also, slender processes of vital granulosa cells which extended into the zona pellucida were positive. This study demonstrates cell-type specificity and cycle-associated regulation for Galectin-3 with increased presence in atretic preantral follicles and in late stages of luteolysis.
