Glucocerebrosidase deficiency and lysosomal storage of glucocerebroside induced in cultured macrophages.
A cell culture model stimulating the genetic deficiency of glucocerebrosidase has been developed, utilizing macrophages and conduritol B epoxide (CBE), the specific irreversible inhibitor of the enzyme. Rat peritoneal macrophage glucocerebrosidase was completely inhibited when cells were treated with 10 microM CBE for 16 h or 100 microM CBE for 2 h. The t1/2 of inactivation was 30 min at 10 microM concentration. When cells were washed free of CBE, the enzyme activity reappeared linearly with time, reaching 50% of control activity 48 h after removal of the inhibitor. CBE-treated macrophages have normal phagocytic activity toward [3H]glycine-coupled latex beads and a normal number of mannose receptors. CBE was found to have no effect on other lysosomal enzymes. When [14C]glucocerebroside, encapsulated in multilamellar liposomes with alpha-D-mannopyranoside covalently coupled to the surface, was fed to glucocerebrosidase-depleted macrophages, the radiolabelled glycolipid accumulated and was undegraded. Subcellular fractionation on a Percoll density gradient demonstrated that the stored glucocerebroside in the CBE-treated macrophages was localized in lysosomes.
D000818:Animals; D002250:Carbon Radioisotopes; D002478:Cells, Cultured; D002554:Cerebrosides / Q000378:metabolism*; D005959:Glucosidases / Q000172:deficiency*; D005962:Glucosylceramidase / Q000037:antagonists & inhibitors / Q000172:deficiency*; D005963:Glucosylceramides / Q000378:metabolism*; D007294:Inositol / Q000031:analogs & derivatives / Q000494:pharmacology; D007700:Kinetics; D008081:Liposomes; D008247:Lysosomes / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D051381:Rats
D002250:Carbon Radioisotopes; D002554:Cerebrosides; D005963:Glucosylceramides; D008081:Liposomes; D007294:Inositol; D005959:Glucosidases; D005962:Glucosylceramidase; C011423:conduritol epoxide