| 1. |
- Burguillos Garcia, Miguel, et al.
(författare)
-
Microglia-Secreted Galectin-3 Acts as a Toll-like Receptor 4 Ligand and Contributes to Microglial Activation.
- 2015
-
Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 10:9, s. 1626-1638
-
Tidskriftsartikel (refereegranskat)abstract
- Inflammatory response induced by microglia plays a critical role in the demise of neuronal populations in neuroinflammatory diseases. Although the role of toll-like receptor 4 (TLR4) in microglia's inflammatory response is fully acknowledged, little is known about endogenous ligands that trigger TLR4 activation. Here, we report that galectin-3 (Gal3) released by microglia acts as an endogenous paracrine TLR4 ligand. Gal3-TLR4 interaction was further confirmed in a murine neuroinflammatory model (intranigral lipopolysaccharide [LPS] injection) and in human stroke subjects. Depletion of Gal3 exerted neuroprotective and anti-inflammatory effects following global brain ischemia and in the neuroinflammatory LPS model. These results suggest that Gal3-dependent-TLR4 activation could contribute to sustained microglia activation, prolonging the inflammatory response in the brain.
|
|
| 2. |
- Carlsson, Michael, et al.
(författare)
-
Galectin-1-binding glycoforms of haptoglobin with altered intracellular trafficking, and increase in metastatic breast cancer patients.
- 2011
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:10
-
Tidskriftsartikel (refereegranskat)abstract
- Sera from 25 metastatic breast cancer patients and 25 healthy controls were subjected to affinity chromatography using immobilized galectin-1. Serum from the healthy subjects contained on average 1.2 mg per ml (range 0.7-2.2) galectin-1 binding glycoproteins, whereas serum from the breast cancer patients contained on average 2.2 mg/ml (range 0.8-3.9), with a higher average for large primary tumours. The major bound glycoproteins were α-2-macroglobulin, IgM and haptoglobin. Both the IgM and haptoglobin concentrations were similar in cancer compared to control sera, but the percentage bound to galectin-1 was lower for IgM and higher for haptoglobin: about 50% (range 20-80) in cancer sera and about 30% (range 25-50) in healthy sera. Galectin-1 binding and non-binding fractions were separated by affinity chromatography from pooled haptoglobin from healthy sera. The N-glycans of each fraction were analyzed by mass spectrometry, and the structural differences and galectin-1 mutants were used to identify possible galectin-1 binding sites. Galectin-1 binding and non-binding fractions were also analyzed regarding their haptoglobin function. Both were similar in forming complex with haemoglobin and mediate its uptake into alternatively activated macrophages. However, after uptake there was a dramatic difference in intracellular targeting, with the galectin-1 non-binding fraction going to a LAMP-2 positive compartment (lysosomes), while the galectin-1 binding fraction went to larger galectin-1 positive granules. In conclusion, galectin-1 detects a new type of functional biomarker for cancer: a specific type of glycoform of haptoglobin, and possibly other serum glycoproteins, with a different function after uptake into tissue cells.
|
|
| 3. |
|
|
| 4. |
- Cumpstey, Ian, et al.
(författare)
-
Double Affinity Amplification of Galectin-Ligand Interactions through Arginine-Arene Interactions: Synthetic, Thermodynamic, and Computational Studies with Aromatic Diamido-Thiodigalactosides.
- 2008
-
Ingår i: Chemistry: A European Journal. - : Wiley. - 1521-3765 .- 0947-6539. ; 14:14, s. 4233-4245
-
Tidskriftsartikel (refereegranskat)abstract
- A series of aromatic mono- or diamido-thiodigalactoside derivatives were synthesized and studied as ligands for galectin-1, -3, -7, -8N terminal domain, and -9N terminal domain. The affinity determination in vitro with competitive fluorescence-polarization experiments and thermodynamic analysis by isothermal microcalorimetry provided a coherent picture of structural requirements for arginine-arene interactions in galectin-ligand binding. Computational studies were employed to explain binding preferences for the different galectins. Galectin-3 formed two almost ideal arene-arginine stacking interactions according to computer modeling and also had the highest affinity for the diamido-thiodigalactosides (K(d) below 50 nM). Site-directed mutagenesis of galectin-3 arginines involved in binding corroborated the importance of their interaction with the aromatic diamido-thiodigalactosides. Furthermore, the arginine mutants revealed distinct differences between free, flexible, and solvent-exposed arginine side chains and tightly ion-paired arginine side chains in interactions with aromatic systems.
|
|
| 5. |
- Cumpstey, Ian, et al.
(författare)
-
Studies of arginine-arene interactions through synthesis and evaluation of a series of galectin-binding aromatic lactose esters
- 2007
-
Ingår i: ChemBioChem. - : Wiley. - 1439-4227 .- 1439-7633. ; 8:12, s. 1389-1398
-
Tidskriftsartikel (refereegranskat)abstract
- Aromatic lactose 2-O-esters were synthesized and used to probe arene-arginine interactions with the galectin family of proteins. They were found to be low mu m inhibitors of galectin-1, -3, and -9N-terminal domain and moderate inhibitors of galectin-7, but not inhibitors of galectin-8N-terminal, which locks an arginine residue close to the critical, esterified lactose 2-O-position. Molecular modeling of galectins in complex with aromatic lactose 2-O-esters, as well as binding studies with a galectin-3 R186S mutant, confirmed that the inhibitory efficiency of the lactose 2-O-esters was due to the formation of strong interactions between the aromatic ester moieties and the arginine guanidinium groups of galectin-1 and -3. An important common feature shared by galectin-1 and -3 was that the arginines formed in-plane ion pairs with two side-chain carboxylates, which resulted in extended planar pi-electron surfaces that did not require solvation by water; these surfaces were ideal for stocking with aromatic moieties of the ligands. The results provide a basis for the design of lectin inhibitors and drugs that exploit interactions with arginine side-chains via aromatic moieties, which are involved in intramolecular protein salt bridges.
|
|
| 6. |
- Delacour, Delphine, et al.
(författare)
-
Apical sorting by galectin-3-dependent glycoprotein clustering
- 2007
-
Ingår i: Traffic: the International Journal of Intracellular Transport. - : Wiley. - 1398-9219. ; 8:4, s. 379-388
-
Tidskriftsartikel (refereegranskat)abstract
- Epithelial cells are characterized by their polarized organization based on an apical membrane that is separated from the basolateral membrane domain by tight junctions. Maintenance of this morphology is guaranteed by highly specific sorting machinery that separates lipids and proteins into different carrier populations for the apical or basolateral cell surface. Lipid-raft-independent apical carrier vesicles harbour the beta-galactoside-binding lectin galectin-3, which interacts directly with apical cargo in a glycan-dependent manner. These glycoproteins are mistargeted to the basolateral membrane in galectin-3-depleted cells, dedicating a central role to this lectin in raft-independent sorting as apical receptor. Here, we demonstrate that high-molecular-weight clusters are exclusively formed in the presence of galectin-3. Their stability is sensitive to increased carbohydrate concentrations, and cluster formation as well as apical sorting are perturbed in glycosylation-deficient Madin-Darby canine kidney (MDCK) II cells. Together, our data suggest that glycoprotein cross-linking by galectin-3 is required for apical sorting of non-raft-associated cargo.
|
|
| 7. |
|
|
| 8. |
- Forsman, Huamei, et al.
(författare)
-
The beta-galactoside binding immunomodulatory lectin galectin-3 reverses the desensitized state induced in neutrophils by the chemotactic peptide f-Met-Leu-Phe: role of reactive oxygen species generated by the NADPH-oxidase and inactivation of the agonist
- 2008
-
Ingår i: Glycobiology. - : Oxford University Press (OUP). - 1460-2423 .- 0959-6658. ; 18:11, s. 905-12
-
Tidskriftsartikel (refereegranskat)abstract
- Neutrophils interacting with a chemoattractant gradually become nonresponsive to further stimulation by the same agonist, a process known as desensitization. Receptor desensitization is a highly regulated process that involves different mechanisms depending on which receptor-ligand pair that is studied. Galectin-3, a member of a large family of beta-galactoside-binding lectins, has been suggested to be a regulator of the inflammatory process, augmenting or directly triggering the neutrophil functional repertoire. We show here that the desensitized state of neutrophils interacting with the chemotactic peptide fMLF is broken by galectin-3 and that this is achieved through an oxygen radical-mediated inactivation of the chemoattractant. The effect was inhibited by the competitor lactose and required the affinity of galectin-3 for N-acetyllactosamine, a saccharide typically found on cell surface glycoproteins. The latter was shown using a galectin-3 mutant that lacked N-acetyllactosamine binding activity, and this protein was not active. The mechanism behind the inactivation of the chemoattractant was found to depend on the ability of galectin-3 to induce a neutrophil generation/secretion of reactive oxygen species which in combined action with myeloperoxidase inactivated the peptides.
|
|
| 9. |
- Gouin, Sebastien G., et al.
(författare)
-
Multimeric Lactoside "Click Clusters" as Tools to Investigate the Effect of Linker Length in Specific Interactions with Peanut Lectin, Galectin-1, and-3
- 2010
-
Ingår i: ChemBioChem. - : Wiley. - 1439-4227 .- 1439-7633. ; 11:10, s. 1430-1442
-
Tidskriftsartikel (refereegranskat)abstract
- Multimeric lactosides based on carbohydrate scaffolds with valencies ranging from 1 to 4 and different linker lengths were synthesized by a copper-catalyzed azide-alkyne cycloaddition (CuAAC). The binding affinities and crosslinking abilities of the new "click clusters" toward biologically relevant galectins (gal-1, gal-3) and peanut lectin were evaluated by fluorescent polarization assay (FPA) and enzyme-linked lectin assay (ELLA), respectively. FPA indicated that the binding affinities of the synthetic multilactosides towards the galectins increased proportionally with their lactosyl content, without significant differences due to the spacer length. ELLA evidenced a modest cluster effect for the multivalent conjugates, with a relative potency per lactoside ranging from 2.1 to 3.2. Nearly identical binding affinities were recorded for derivatives differing in the length of the linkers, in agreement with the FPA data. These results demonstrate that this parameter does not significantly influence the recognition process when interactions occur at a single lectin site. Molecular dynamics revealed that glycoconjugates adopt a pseudoglobular structure with a random localization of the lactoside residues. These spatial distributions were observed irrespective of the linker length; this explains the virtually equal affinities recorded by ELLA. In contrast, two-site "sandwich" ELLA clearly revealed that multivalent derivatives bearing the longest spacers were more efficient for crosslinking lectins. Intrinsic affinities, devoid of aggregation effects, and crosslinking capabilities are, therefore, not directly related phenomena that must be taking into consideration in neoglycoconjugate design for specific applications.
|
|
| 10. |
- Jonsson, Emma, et al.
(författare)
-
Swedish osteoporosis care
- 2015
-
Ingår i: ARCHIVES OF OSTEOPOROSIS. - : Springer Science and Business Media LLC. - 1862-3522 .- 1862-3514. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- Mini-abstract The objective of this study was to review and describe the current state of Swedish osteoporosis care and to highlight ongoing challenges. This report encompasses quantitative health outcomes based on Swedish registry data as well as organizational and management aspects. Executive summary Swedish osteoporosis care is characterized by a significant burden of disease, difficulties in identifying high-risk patients, and fragmented pathways for patients in need of secondary fracture prevention. This report aimed to describe the current state, gaps, and challenges in Swedish osteoporosis care, using Swedish national databases, questionnaires, and interviews with healthcare representatives. A secondary aim was to develop quality and process measures to compare differences between counties and to use those measures to describe the interaction between quantitative health outcomes and aspects of care organization and management. In conjunction with fractures, a considerably smaller proportion of men are treated than women, and a smaller proportion of older women are treated compared to younger groups. Between 3 and 16 % of patients receive treatment after a fracture, and the treatment rate in this patient group can likely increase. In addition to an unsatisfactory treatment rate, a limited number of those treated continue treatment throughout the recommended treatment durations, leading to increased risk of fracture. With a substantial variation between counties, there is a clear difficulty to identify non-persistent patients and switch to an alternative treatment. Collaboration around the patient across specialties has been lacking, and systems for secondary prevention have been concentrated to a few counties. However, when this study was conducted, there was a general trend towards implementing regional care programs. This report suggests possible strategies for improving quality of care and, hopefully, it can provide a basis for future evaluations and regional improvement of osteoporosis care in Sweden and other countries.
|
|
