REGULATION OF HUMAN MONONUCLEAR PHAGOCYTE MIGRATION BY CELL-SURFACE BINDING-PROTEINS FOR ADVANCED GLYCATION END-PRODUCTS

Nonenzymatic glycation of proteins occurs at an accelerated rate in di abetes and can lead to the formation of advanced glycation end product s of proteins (AGEs), which bind to mononuclear phagocytes (MPs) and i nduce chemotaxis. We have isolated two cell surface-associated binding proteins that mediate the interaction of AGEs with bovine endothelial cells. One of these proteins is a new member of the immunoglobulin su per-family of receptors (termed receptor for AGEs or RAGE); and the se cond is a lactoferrin-like polypeptide (LF-L). Using monospecific anti bodies to these two AGE-binding proteins, we detected immunoreactive m aterial on Western blots of detergent extracts from human MPs. Radioli gand-binding studies demonstrated that antibody to the binding protein s blocked I-125-AGE-albumin binding and endocytosis by MPs. Chemotaxis of human MPs induced by soluble AGE-albumin was prevented in a dose-d ependent manner by intact antibodies raised to the AGE-binding protein s, F(ab')2 fragments of these antibodies and by soluble RAGE. When MP migration in response to N-formyl-Met-Leu-Phe was studied in a chemota xis chamber with AGE-albumin adsorbed to the upper surface of the cham ber membrane, movement of MPs to the lower compartment was decreased b ecause of interaction of the glycated proteins with RAGE and LF-L on t he cell surface. The capacity of AGEs to attract and retain MPs was sh own by implanting polytetrafluoroethylene (PTFE) mesh impregnated with AGE-albumin into rats: within 4 d a florid mononuclear cell infiltrat e was evident in contrast to the lack of a significant cellular respon se to PTFE with adsorbed native albumin. These data indicate that RAGE and LF-L have a central role in the interaction of AGEs with human mo nonuclear cells and that AGEs can serve as a nidus to attract MPs in v ivo.