1. Human galectin-1, -2, and -4 induce surface exposure of phosphatidylserine in activated human neutrophils but not in activated T cells.
- Author
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Stowell SR, Karmakar S, Stowell CJ, Dias-Baruffi M, McEver RP, and Cummings RD
- Subjects
- Apoptosis, Cell Line, Tumor cytology, Cell Line, Tumor drug effects, Cells, Cultured cytology, Cells, Cultured drug effects, Dithiothreitol pharmacology, Galectin 1 physiology, Galectin 2 physiology, Galectin 4 physiology, HL-60 Cells cytology, HL-60 Cells drug effects, HL-60 Cells metabolism, Humans, Lymphocyte Activation, N-Formylmethionine Leucyl-Phenylalanine pharmacology, Neutrophils drug effects, Neutrophils immunology, Organ Specificity, Oxidation-Reduction, Recombinant Fusion Proteins pharmacology, Respiratory Burst, Surface Properties, T-Lymphocytes drug effects, T-Lymphocytes immunology, Galectin 1 pharmacology, Galectin 2 pharmacology, Galectin 4 pharmacology, Membrane Lipids metabolism, Neutrophils metabolism, Phosphatidylserines metabolism, T-Lymphocytes metabolism
- Abstract
Cellular turnover is associated with exposure of surface phosphatidylserine (PS) in apoptotic cells, leading to their phagocytic recognition and removal. But recent studies indicate that surface PS exposure is not always associated with apoptosis. Here we show that several members of the human galectin family of glycan binding proteins (galectins-1, -2, and -4) induce PS exposure in a carbohydrate-dependent fashion in activated, but not resting, human neutrophils and in several leukocyte cell lines. PS exposure is not associated with apoptosis in activated neutrophils. The exposure of PS in cell lines treated with these galectins is sustained and does not affect cell viability. Unexpectedly, these galectins bind well to activated T lymphocytes, but do not induce either PS exposure or apoptosis, indicating that galectin's effects are cell specific. These results suggest novel immunoregulatory contribution of galectins in regulating leukocyte turnover independently of apoptosis.
- Published
- 2007
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