title: Macrophage recognition of thiol-group oxidized cells: recognition of carbohydrate chains by macrophage surface nucleolin as apoptotic cells.
abstract: The mechanism was investigated for macrophage recognition of cells oxidized by diamide, a thiol group-specific oxidizing reagent. Jurkat cells exposed to various concentrations of diamide were recognized by macrophages, the cells exposed to 25 µM diamide being best recognized. CD43, a major glycoprotein on the Jurkat cell surface, tended to form clusters upon diamide oxidization, and pretreating Jurkat cells with the anti-CD43 antibody inhibited macrophage binding. This indicates that macrophages appeared to recognize CD43. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and a Western blot analysis of CD43 of the diamide-oxidized cells showed no increase in the amount of cross-linked CD43 compared with control cells, indicating that cross-linking of CD43 by a disulphide bond was not involved in the clustering. Both CD43 clustering and binding of the oxidized cells to macrophages was prevented by the caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethyl ketone (Z-VAD-fmk), suggesting that the oxidized and macrophage-bound cells were undergoing apoptosis. A closer examination revealed that the caspase-3 activity, chromatin condensation, and DNA fragmentation in Jurkat cells were all increased by oxidation. The macrophage receptor involved in the binding appeared to be the cell-surface protein, nucleolin; an anti-nucleolin antibody treatment inhibited the binding. These results suggest that thiol group-oxidized cells underwent early apoptosis and were recognized by nucleolin on macrophages as early apoptotic cells.
authors.affiliation: School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan. miki@ps.toyaku.ac.jp
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Miki
authors.forename: Kazuya
authors.initials: K
authors.lastname: Hirano
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Beppu
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D050260:Carbohydrate Metabolism / Q000187:drug effects; D003958:Diamide / Q000494:pharmacology; D006801:Humans; D019169:Jurkat Cells; D008024:Ligands; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D016601:RNA-Binding Proteins / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D000097796:Nucleolin
chemical_list: D003958:Diamide; D008024:Ligands; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D013438:Sulfhydryl Compounds; D000097796:Nucleolin