Swainsonine inhibits macrophage receptor-mediated uptake and degradation of a mannosyl-oligosaccharide.
Rat pulmonary macrophages were incubated in the presence of a radiolabeled mannosyl-oligosaccharide obtained from ovalbumin. Receptor-mediated endocytosis and degradation of this ligand by the cells was followed in the presence or absence of swainsonine, an inhibitor of alpha-mannosidases. The results indicated that at higher concentrations (greater than 1 microgram/ml) of swainsonine, both the internalization and degradation of the radiolabeled ligand were inhibited. At a concentration of 0.1 microgram/ml of swainsonine, only the degradation was inhibited while the uptake was unaltered. The degradation of the oligosaccharide was blocked due to the inhibition of lysosomal alpha-mannosidase. However, the inhibition of lysosomal alpha-mannosidase was reversible upon withdrawal of swainsonine.
D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D004705:Endocytosis / Q000187:drug effects; D005260:Female; D007700:Kinetics; D008247:Lysosomes / Q000187:drug effects / Q000201:enzymology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008358:Mannose; D008361:Mannosidases / Q000037:antagonists & inhibitors; D009844:Oligosaccharides / Q000378:metabolism*; D010047:Ovalbumin; D051381:Rats; D011919:Rats, Inbred Strains; D017026:Swainsonine; D043323:alpha-Mannosidase
D000470:Alkaloids; D009844:Oligosaccharides; D010047:Ovalbumin; D008361:Mannosidases; D043323:alpha-Mannosidase; D008358:Mannose; D017026:Swainsonine