| 1. |
- Carlsson, Michael, et al.
(författare)
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Galectin-1-binding glycoforms of haptoglobin with altered intracellular trafficking, and increase in metastatic breast cancer patients.
- 2011
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:10
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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.
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| 2. |
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| 3. |
- Cederfur, Cecilia
(författare)
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Galectin binding proteins in serum and bronchoalveolar lavage -in healthy and pathological conditions
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Galectins are carbohydrate binding proteins, implicated in conditions of both inflammation and cancer. Connections between chronic inflammation and cancer are proposed by the increased remodelling and proliferation that occurs, leading to enhanced survival and proliferation of malignant cells. Since galectins have been implicated in mechanisms of both chronic inflammation and cancer, we have investigated natural binding partners of galectins in healthy individuals and then continued with studying states of cancer and chronic inflammation. We identified galectin binding glycoproteins in sera from healthy individuals and found that galectins widely expressed in the body bind serum glycoproteins well, whereas galectins with a more tissue-specific distribution scarcely binds any serum glycoproteins. We then chose the widely expressed but intermediately binding galectin-1 to detect if levels of galectin-1-binding proteins are increased in sera of breast cancer patients. We found that galectin-1 binds approximately double the amount in breast cancer patients compared to healthy individuals. The increase was mainly caused by haptoglobin, probably due to both increased expression and changes of glycosylation. To further investigate the inflammatory connection we identified galectin binding proteins from bronchoalveolar lavage of asthma patients and healthy individuals, additionally we compared the binding of galectin-3 and galectin-8 that are expressed in different sites of the lung. We found when functionally grouping the bound proteins that galectin-3 and -8 binding proteins had different profiles and that bound proteins of healthy and asthma patients differed.
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| 4. |
- Cederfur, Cecilia, et al.
(författare)
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Glycoproteomic identification of galectin-3 and -8 ligands in bronchoalveolar lavage of mild asthmatics and healthy subjects.
- 2012
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Ingår i: Biochimica et biophysica acta. - : Elsevier BV. - 0006-3002 .- 0304-4165. ; 1820:9, s. 1429-1436
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Tidskriftsartikel (refereegranskat)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 (10-30μg) and galectin bound (~1-10μg) 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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| 5. |
- Paz, Irit, et al.
(författare)
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Galectin-3, a marker for vacuole lysis by invasive pathogens
- 2010
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Ingår i: Cellular Microbiology. - : Hindawi Limited. - 1462-5814 .- 1462-5822. ; 12:4, s. 530-544
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Tidskriftsartikel (refereegranskat)abstract
- P>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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