| 1. |
- Almkvist, Jenny, 1971, et al.
(författare)
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Activation of the neutrophil nicotinamide adenine dinucleotide phosphate oxidase by galectin-1.
- 2002
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - 0022-1767. ; 168:8, s. 4034-4041
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Tidskriftsartikel (refereegranskat)abstract
- Galectins are a group of lactose-binding proteins widely distributed in nature. Twelve mammalian galectins have so far been identified, but their functions are to a large extent unknown. In this work we study galectin-1 in its interaction with human neutrophils, with regard to both cell surface binding and activation of the superoxide-producing NADPH-oxidase. We show that galectin-1 is able to activate the neutrophil NADPH-oxidase, provided that the cells have been primed by extravasation from the blood into the tissue, an activation pattern that is similar to that of galectin-3. Using in vitro priming protocols, the galectin-1 responsiveness was found to correlate to granule mobilization and galectin-1 binding to the cells, suggesting the presence of granule-localized receptors that are up-regulated to the cell surface upon priming. By galectin-1 overlay of fractionated neutrophils we identified potential galectin-1 receptor candidates localized in the membranes of the secretory vesicle and gelatinase granules. The binding of galectin-1 and galectin-3 to neutrophil proteins was compared, as were the dose dependencies for activation by the two lectins. The results suggest that, although similarities are found between the two galectins, they appear to activate the NADPH-oxidase using different receptors. In conclusion, galectin-1 appears to have proinflammatory functions, mediated through activation of the neutrophil respiratory burst.
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| 2. |
- Almkvist, Jenny, 1971, et al.
(författare)
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Lipopolysaccharide-induced gelatinase granule mobilization primes neutrophils for activation by galectin-3 and formylmethionyl-Leu-Phe.
- 2001
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Ingår i: Infection and immunity. - 0019-9567 .- 1098-5522. ; 69:2, s. 832-7
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Tidskriftsartikel (refereegranskat)abstract
- We have earlier shown that galectin-3, a lactose-binding mammalian lectin that is secreted from activated macrophages, basophils, and mast cells, induces activation of the NADPH oxidase in exudated but not in peripheral blood neutrophils (A. Karlsson, P. Follin, H. Leffler, and C. Dahlgren, Blood 91:3430-3438, 1998). The alteration in responsiveness occurring during extravasation correlated with mobilization of the gelatinase and/or specific granules to the cell surface, indicating a role for mobilizable galectin-3 receptors. In this study we have investigated galectin-3-induced NADPH oxidase activation, measured as superoxide production, in lipopolysaccharide (LPS)-primed neutrophils. Upon galectin-3 challenge, the LPS-primed cells produced superoxide, both extracellularly and intracellularly. A primed extracellular response to formylmethionyl-Leu-Phe (fMLF) was also achieved. The exposure of complement receptors 1 and 3 as well as the formyl peptide receptor on the cell surface was markedly increased after LPS treatment, indicating that granule fusion with the plasma membrane had occurred. Further assessment of specific markers for neutrophil granules showed that the LPS treatment had mobilized the gelatinase granules but only a minor fraction of the specific granules. We thus suggest that the mechanism behind LPS priming lies at the level of granule (receptor) mobilization for galectin-3 as well as for fMLF.
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| 3. |
- Almkvist, Jenny, 1971, et al.
(författare)
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Newcastle disease virus neuraminidase primes neutrophils for stimulation by galectin-3 and formyl-Met-Leu-Phe
- 2004
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Ingår i: Experimental cell research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 298:1, s. 74-82
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Tidskriftsartikel (refereegranskat)abstract
- Human neutrophils are activated by the beta-galactoside-binding lectin galectin-3, provided that the cells are primed by in vivo extravasation or by in vitro preactivation with, for example, LPS. Removal of terminal sialic acid can change neutrophil functionality and responsiveness due to exposure of underlying glycoconjugate receptors or change in surface charge. Here, we investigated whether such alteration of the cell surface carbohydrate composition can alter the responsiveness of the cells to galectin-3. Neutrophils were treated with neuraminidases (NA) of different origins: Clostridium perfringens (CP), Salmonella typhimurium, Vibrio cholerae, and Newcastle disease virus (NDV). In the presence of NDV-NA, but no other NA, the otherwise non-responding neutrophils responded readily to galectin-3 by activation of the NADPH-oxidase. The galectin-3 priming effect was inhibited by the sialidase inhibitor 2,3-dehydro-2-deoxy-N-acetyl-neuraminic acid. Earlier studies have shown that priming of the neutrophil response to galectin-3 with, for example, LPS is paralleled by degranulation of intracellular vesicles and granules and upregulation of potential galectin-3 receptors. Also, NDV-NA (but not CP-NA) treatment induced degranulation, shown as an upregulation of complement receptor 3. Since not only the galectin response but also the response to the chemoattractant fMLF was primed, NDV-NA appears to induce a general priming phenomenon, possibly due to receptor upregulation by degranulation.
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| 4. |
- Capon, C, et al.
(författare)
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Sd(a)-antigen-like structures carried on core 3 are prominent features of glycans from the mucin of normal human descending colon
- 2001
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Ingår i: Biochemical Journal. - 0264-6021. ; 358:Pt 3, s. 657-664
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes structural characterization by NMR, MS and degradative studies of mucin glycans from normal human descending colon obtained freshly at autopsy. The saccharides were mainly based on core 3 (GlcNAcbeta1-3GalNAc). Among the terminal saccharide determinants Sd(a)/Cad-antigen-like structures were prominent, and Lewis x, sialyl Lewis x and sulphated Lewis x were found as minor components, whereas blood group H and A antigenic determinants were absent. The saccharides were markedly different from those of mucins from colon cancers or colon cancer cell lines analysed so far, in which cores 1 and 2 are prominent features, and in which various other terminal determinants have been found, but not Sd(a)/Cad.
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| 5. |
- Houzelstein, D, et al.
(författare)
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Phylogenetic analysis of the vertebrate galectin family
- 2004
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Ingår i: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 21:7, s. 1177-1187
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Tidskriftsartikel (refereegranskat)abstract
- Galectins form a family of structurally related carbohydrate binding proteins (lectins) that have been identified in a large variety of metazoan phyla. They are involved in many biological processes such as morphogenesis, control of cell death, immunological response, and cancer. To elucidate the evolutionary history of galectins and galectin-like proteins in chordates, we have exploited three independent lines of evidence: (i) location of galectin encoding genes (LGALS) in the human genome; (ii) exon-intron organization of galectin encoding genes; and (iii) sequence comparison of carbohydrate recognition domains (CRDs) of chordate galectins. Our results suggest that a duplication of a mono-CRD galectin gene gave rise to an original bi-CRD galectin gene, before or early in chordate evolution. The N-terminal and C-terminal CRDs of this original galectin subsequently diverged into two different subtypes, defined by exon-intron structure (F4-CRD and F3-CRD). We show that all vertebrate mono-CRD galectins known to date belong to either the F3- or F4-subtype. A sequence of duplication and divergence events of the different galectins in chordates is proposed.
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| 6. |
- Huflejt, ME, et al.
(författare)
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Galectin-4 in normal tissues and cancer
- 2003
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Ingår i: Glycoconjugate Journal. - 1573-4986. ; 20:4, s. 247-255
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Tidskriftsartikel (refereegranskat)abstract
- Galectin-4 belongs to a subfamily of galectins composed of two carbohydrate recognition domains within the same peptide chain. The two domains have all the conserved galectin signature amino acids, but their overall sequences are only approximately 40% identical. Both domains bind lactose with a similar affinity as other galectins, but their respective preferences for other disaccharides, and larger saccharides, are distinctly different. Thus galectin-4 has a property of a natural cross-linker, but in a modified sense since each domain prefers a different subset of ligands. Similarly to other galectins, galectin-4 is synthesized as a cytosolic protein, but can be externalized. During development and in adult normal tissues, galectin-4 is expressed only in the alimentary tract, from the tongue to the large intestine. It is often found in relatively insoluble complexes, as a component of either adherens junctions or lipid rafts in the microvillus membrane, and it has been proposed to stabilize these structures. Strong expression of galectin-4 can be induced, however, in cancers from other tissues including breast and liver. Within a collection of human epithelial cancer cell lines, galectin-4 is overexpressed and soluble in those forming highly differentiated polarized monolayers, but absent in less differentiated ones. In cultured cells, intracellular galectin-4 may promote resistance to nutrient starvation, whereas-as an extracellular protein-it can mediate cell adhesion. Because of its distinct induction in breast and other cancers, it may be a valuable diagnostic marker and target for the development of inhibitory carbohydrate-based drugs.
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| 7. |
- Jain, Nitin U., et al.
(författare)
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Distance mapping of protein-binding sites using spin-labeled oligosaccharide ligands
- 2001
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Ingår i: Protein Science. - : Wiley. - 1469-896X .- 0961-8368. ; 10:11, s. 2393-2400
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Tidskriftsartikel (refereegranskat)abstract
- The binding of a nitroxide spin-labeled analog of N-acetyllactosamine to galectin-3, a mammalian lectin of 26 kD size, is studied to map the binding sites of this small oligosaccharide on the protein surface. Perturbation of intensities of cross-peaks in the (15)N heteronuclear single quantum coherence (HSQC) spectrum of full-length galectin-3 owing to the bound spin label is used qualitatively to identify protein residues proximate to the binding site for N-acetyllactosamine. A protocol for converting intensity measurements to a more quantitative determination of distances between discrete protein amide protons and the bound spin label is then described. This protocol is discussed as part of a drug design strategy in which subsequent perturbation of chemical shifts of distance mapped amide cross-peaks can be used effectively to screen a library of compounds for other ligands that bind to the target protein at distances suitable for chemical linkage to the primary ligand. This approach is novel in that it bypasses the need for structure determination and resonance assignment of the target protein.
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| 8. |
- John, Constance M, et al.
(författare)
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Galectin-3 binds lactosaminylated lipooligosaccharides from Neisseria gonorrhoeae and is selectively expressed by mucosal epithelial cells that are infected
- 2002
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Ingår i: Cellular Microbiology. - : Hindawi Limited. - 1462-5814 .- 1462-5822. ; 4:10, s. 649-661
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Tidskriftsartikel (refereegranskat)abstract
- Galectins are a family of beta-galactoside binding proteins that have been proposed as host receptors for bacteria because beta-galactoside carbohydrates are common in bacterial membrane glycolipid lipooligosaccharides (LOS) and lipopolysaccharides. We investigated the interaction of galectin-3 with gonococcal LOS that make lactosyl (Lc(2) or Lac), paraglobosyl (nLc(4) ; LNnT; lacto-N -neotetraose), gangliosyl (IV3 GalNAcnLc(4) ), and neolactohexaosyl (nLc(6) , lactonorhexaosyl) oligosaccharides. All but gangliosyl LOS terminate in beta-galactoside. Galectin-3 had the highest affinity for the nLc(6) LOS, which is made by a strain that is highly infectious for the male urethra, but also bound nLc(4) LOS and to a Lac LOS. The lacto-N -neotetraose tetrasaccharide was a more potent inhibitor of galectin-3 binding to LOS than either lactose or N -acetyllactosamine. The relative affinity of galectin-3 for gonococci mirrored its affinity for purified LOS. Western blot analysis revealed expression of galectin-3 by human endometrial adenocarcinoma and prostatic epithelial cells that can be invaded by gonococci. Immunohistochemistry of human fallopian tube epithelium showed localized expression of galectin-3 by non-ciliated cells, the specific cell gonococci invade in this tissue. We conclude that because of its location and affinity for gonococcal LOS galectin-3 could play a role in gonococcal infection.
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| 9. |
- John, CM, et al.
(författare)
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Truncated galectin-3 inhibits tumor growth and metastasis in orthotopic nude mouse model of human breast cancer
- 2003
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Ingår i: Clinical Cancer Research. - 1078-0432. ; 9:6, s. 2374-2383
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The goal of this research was to evaluate a potential therapeutic agent for breast cancer based on galectin-3 that has been implicated in tumorigenicity and metastasis of breast cancer. The hypothesis was that therapy with NH2-terminally truncated form of galectin-3 (galectin-3C) will be efficacious for reduction in tumor growth and for inhibition of metastases. Experimental Design: Recombinant human galectin-3 was produced in Escherichia coli from which galectin-3C was derived by collagenase enzyme digestion. Toxicity, pharmacokinetic, and organ biodistribution studies were performed in nude mice. For efficacy studies, nude mice bearing orthotopically implanted tumors derived from breast cancer cell line MDA-MB-435 were treated with galectin-3C or a vehicle control i.m. twice daily for 90 days. Results: The maximum tolerated dose of galectin-3C in nude mice was determined to be >125 mg/kg without overt adverse effects. The elimination half-life when administered i.m. was found to be 3.0 h in the serum and 4.3 h in the cellular fraction of the blood. Organ biodistribution studies revealed that galectin-3C localized in the liver, kidneys, and spleen but not in the heart or lungs. We found that the mean tumor volumes and weights were statistically significantly less in mice treated with galectin-3C compared with control mice, and that fewer numbers of mice exhibited lymph node metastases in the treated group compared with the control group. Conclusions: Galectin-3C is not overtly toxic, and is efficacious in reducing metastases and tumor volumes and weights in primary tumors in an orthotopic nude mouse model of human breast cancer.
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| 10. |
- Leffler, Hakon
(författare)
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Galectins structure and function--a synopsis
- 2001
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Ingår i: Results and Problems in Cell Differentiation. - 0080-1844. ; 33, s. 57-83
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Tidskriftsartikel (refereegranskat)abstract
- The 20 or so galectins expected to be found in man, and their many possible functional effects promise a rich and fruitful research field in the future. At present, the biomedically most promising areas for use of galectins or their ligands are in inflammation, immunity, and cancer. Many good stories can be formulated, but the field lacks the cohesion of knowing basic galectin function. The only basic common denominators among galectins are beta-galactoside binding, and the unusual combination of intra- and extracellular expression with non-classical secretion in between. Maybe that is all there is, and nature has used these properties for multiple, otherwise unrelated functions. Then again, maybe there is some deeper common function that has so far been overlooked. If it exists, this probably lies somewhere in the detailed integration of galectin activity in the complexities of cell physiology.
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