Histone functions as a cell-surface receptor for AGEs

Reducing sugars can covalently react with proteins to generate a heterogeneous and complex group of compounds called advanced glycation end products (AGEs). AGEs are generally considered as pathogenic molecules, mediating a pro-inflammatory response and contributing to the development of a number of human diseases. However, the intrinsic function of AGEs remains to be elucidated. We now provide multiple lines of evidence showing that AGEs can specifically bind a cell-surface protein and regulate its functions. To identify cellular binding partners for AGEs, we used dehydroascorbic acid (DHA)-modified serum albumins as one of the AGEs to screen for binding proteins in the lipid raft fraction prepared from mouse splenocytes and identified histone localized on the cell-surface as an AGE-binding protein. Histone ubiquitously recognized AGEs, including proteins modified with glucose and its metabolites. AGEs inhibited the binding of plasminogen to the histone component H2B which functions as a cell-surface plasminogen receptor on monocytes/macrophages. Moreover, AGEs regulated the recruitment of monocytes/macrophage to the site of inflammation. Our discovery of histone as a cell-surface receptor for AGEs suggests that, beside our common concept of AGEs as danger-associated molecular patterns mediating a pro-inflammatory response, they may also be involved in the homeostatic response via binding to histone. Overall design: We evaluated transcripts in peritoneal macrophages derived from mice treated with BSA or AGEs by RNA-seq.