Opposite effects of galectin-1 on alternative metabolic pathways of L-arginine in resident, inflammatory, and activated macrophages.
Glycobiology
; 13(2): 119-28, 2003 Feb.
Article
in En
| MEDLINE
| ID: mdl-12626408
ABSTRACT
Recent evidence has implicated galectins and their carbohydrate ligands as master regulators of the inflammatory response. Galectin-1, a member of this family, has shown specific anti-inflammatory and immunoregulatory effects. To gain insight into the potential mechanisms involved in these effects, we investigated the effects of galectin-1 in L-arginine metabolism of peritoneal rat macrophages. Pretreatment of macrophages with galectin-1 resulted in a dose- and time-dependent inhibition of lipopolysaccharide-induced nitric oxide (NO) production, accompanied by a decrease in inducible nitric oxide synthase (iNOS) expression (the classic pathway of L-arginine). On the other hand, galectin-1 favored the balance toward activation of L-arginase, the alternative metabolic pathway of L-arginine. Inhibition of NO production was not the result of increased macrophage apoptosis because addition of this beta-galactoside-binding protein to macrophages under the same experimental conditions did not affect the apoptotic threshold of these cells. To understand how endogenous galectin-1 is regulated in macrophages under inflammatory stress, we finally explored the ultrastructural distribution, expression, and secretion of galectin-1 in resident, inflammatory, and activated macrophages. This study provides an alternative cellular mechanism based on the modulation of L-arginine metabolism to understand the molecular basis of the anti-inflammatory properties displayed by this carbohydrate-binding protein.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Arginine
/
Galectin 1
/
Macrophages
Limits:
Animals
Language:
En
Journal:
Glycobiology
Journal subject:
BIOQUIMICA
Year:
2003
Document type:
Article
Affiliation country:
Argentina