Expression of fructosyllysine receptors on human monocytes and monocyte-like cell lines

Abstract

Short-term exposure of human serum albumin to glucose in vitro results in the formation of fructosyllysine residues. Using short-term glucose-modified albumin the interactions with human monocytes and with the human monocyte-like cells U937, MonoMac 6, HL60, and THP1 were studied. Short-term glycated albumin was specifically bound by monocytes, U937 and MonoMac 6 cells, but not by HL60 and THP1 cells. This specific binding of short-term glycated albumin was inhibited by fructosyllysine, but not by hexitollysine. Short-term glycated albumin did not compete for binding of albumin, modified by advanced glycation end products. Scatchard analysis of the binding data indicated that there are 10,000 binding sites per cell in monocytes or U937 cells and 2000 sites per cell on MonoMac 6 cells with affinity constants of 9 x 10(6) M-1. Specific binding of short-term glycated albumin to human monocytes was observed in 29% of the 101 human subjects investigated. Ligand-receptor cross-linking and ligand blotting experiments revealed two binding proteins of 100 to 110 and 190 kDa in SDS-PAGE after membrane protein solubilization of U937 and MonoMac 6 cells. The binding of short-term glycated albumin to MonoMac 6 cells induced the production of the cytokines IL-1 and TNF.

Isolation, Purification, and Characterization of Amadoriase Isoenzymes (Fructosyl Amine-oxygen Oxidoreductase EC 1.5.3) from Aspergillus sp.

“…: 216-368-6613; Fax: 216-368-0495; E-mail: vmm3@po.cwru.edu. 1 The abbreviations used are: AGE, advanced glycation end product; BSA, bovine serum albumin; BtmSA, N,O-bis(trimethylsilyl)acetamide; DTT, dithiothreitol; GC/MS, coupled gas chromatography-mass spectrometry; OPD, o-phenylenediamine; PAGE, polyacrylamide gel electrophoresis; PBS, phosphate-buffered saline; PMSF, phenylmethylsulfonyl fluoride; t-Boc, t-butoxycarbonyl; TTC, triphenyltetrazolium chloride; MES, 2-(N-morpholino)ethanesulfonic acid; MOPSO, 3-(Nmorpholino)-2-hydroxypropanesulfonic acid; POPSO, piperazine-1,4-bis(2-hydroxypropanesulfonic acid) dihydrate; CHES, 2-(N-cyclohexylamino)ethanesulfonic acid. tive (18) as described by Bayne (19).…”

“…The Amadori product, which forms in the initial stages of the Maillard reaction in vivo, has been shown to be recognized by receptors at the surface of monocytes, aortic endothelial, and mesangial cells (1)(2)(3), and treatment of diabetic mice with antibodies to glycated albumin decreases the rate of progression of diabetic nephropathy (4). Amadori products of glucose are precursors of the glycoxidation products pentosidine and N ⑀ -(carboxymethyl)lysine (5-7), which are elevated in diabetes and the levels of which increase with the severity of diabetic complications (8 -10).…”

Molecular Cloning and Expression of Amadoriase Isoenzyme (Fructosyl Amine:Oxygen Oxidoreductase, EC 1.5.3) from Aspergillus fumigatus

“…Amadori products are precursors of protein cross-links, fluorescent and UV-active compounds, and glycoxidation products such as pentosidine and N ⑀ -(carboxymethyl)lysine (2-4). Furthermore, Amadori products are a potent source of reactive oxygen species (5, 6) and can be taken up by specific receptors in macrophages and mesangial and aortic cells (7)(8)(9).…”

Amadori-modified glycated serum proteins and accelerated atherosclerosis in diabetes: Pathogenic and therapeutic implications

“…Interaction of the Amadori-glucose epitope with specific cell-associated binding proteins is believed to trigger these and likely other effects (9)(10)(11)(12). Amadori-modified albumin also increases Plasminogen Activator Inhibitor-1 (PAI-1) expression, induces NF-κB and AP-1 DNA binding activity and upregulates Vascular Endothelial Growth Factor (VEGF) expression in peritoneal mesothelial cells (13,14), findings believed to be contributory to neoangiogenesis and structural alterations in the peritoneal membrane in patients undergoing peritoneal dialysis that also may be relevant to cellular activation and plaque formation in atherosclerosis.…”