IMMUNOCYTOCHEMICAL EVIDENCE FOR A MODULATION OF GALECTIN 3 (Mac-2), A CARBOHYDRATE BINDING PROTEIN, IN PULMONARY FIBROSIS
✍ Scribed by KASPER, MICHAEL; HUGHES, R. COLIN
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 973 KB
- Volume
- 179
- Category
- Article
- ISSN
- 0022-3417
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✦ Synopsis
Galectin 3 is an endogenous mammalian carbohydrate-binding protein with affinity for terminal /?-galactose residues, polylactosamine glycans, and ABH-blood group carbohydrate epitopes. To determine the distribution and regulation of galectin 3 during pulmonary injury, which is known to be accompanied by profound changes in the carbohydrate moieties of cell surface glycoproteins of alveolar cells, a rat model of irradiation-induced lung inflammation and repair was used. Immunocytochemistry showed that in normal rat lungs, galectin 3 was localized to alveolar macrophages, with weaker staining of bronchial epithelial cells. Shortly after irradiation-induced lung injury, when there is active proliferation of type I1 alveolar epithelial cells and re-epithelialization of alveolar basement membranes by type I cells, the total galectin concentration in the lung increased dramatically. This increase was due in part to an increased population of galectin 3-positive interstitial and alveolar macrophages. In addition, galectin 3 was expressed prominently a t the surface of the newly formed type I alveolar epithelium and to lesser extent at the apical surface of type I1 cells. These findings suggest that the increased synthesis and secretion of galectin 3 during irradiation-induced lung injury, together with ligation of secreted lectin at the surface of alveolar epithelial cells, may play roles in pulmonary alveolar epithelial expansion and differentiation during injury and repair.