Association of advanced glycation end products with A549 cells, a human pulmonary epithelial cell line, is mediated by a receptor distinct from the scavenger receptor family and RAGE.
Cellular interactions with advanced glycation end products (AGE)-modified proteins are known to induce several biological responses, not only endocytic uptake and degradation, but also the induction of cytokines and growth factors, combined responses that may be linked to the development of diabetic vascular complications. In this study we demonstrate that A549 cells, a human pulmonary epithelial cell line, possess a specific binding site for AGE-modified bovine serum albumin (AGE-BSA) (K(d) = 27.8 nM), and additionally for EN-RAGE (extracellular newly identified RAGE binding protein) (K(d) = 118 nM). Western blot and RT-PCR analysis showed that RAGE (receptor for AGE) is highly expressed on A549 cells, while the expression of other known AGE-receptors such as galectin-3 and SR-A (class A scavenger receptor), are below the level of detection. The binding of (125)I-AGE-BSA to these cells is inhibited by unlabeled AGE-BSA, but not by EN-RAGE. In contrast, the binding of (125)I-EN-RAGE is significantly inhibited by unlabeled EN-RAGE and soluble RAGE, but not by AGE-BSA. Our results indicate that A549 cells possess at least two binding sites, one specific for EN-RAGE and the other specific for AGE-BSA. The latter receptor on A549 cells is distinct from the scavenger receptor family and RAGE.
Nakano
Nahoko
N
Departments of Medical Biochemistry, Psychiatry, and Cell Pathology, Graduate School of Medical and Pharmaceutical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto 860-8556.
Fukuhara-Takaki
Kaori
K
Jono
Tadashi
T
Nakajou
Keisuke
K
Eto
Nobuaki
N
Horiuchi
Seikoh
S
Takeya
Motohiro
M
Nagai
Ryoji
R
D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism*; D017127:Glycation End Products, Advanced / Q000378:metabolism* / Q000493:pharmacokinetics; D006801:Humans; D008168:Lung / Q000378:metabolism; D011485:Protein Binding; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000819:agonists / Q000145:classification*; D051116:Receptors, Scavenger / Q000819:agonists / Q000145:classification / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000378:metabolism / Q000493:pharmacokinetics; D015398:Signal Transduction; D013379:Substrate Specificity
D017127:Glycation End Products, Advanced; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; D051116:Receptors, Scavenger; D011994:Recombinant Proteins; C081628:advanced glycation end products-bovine serum albumin; D012710:Serum Albumin, Bovine