title: Glycated serum albumin induces chemokine gene expression in human retinal pigment epithelial cells.
abstract: Chronic hyperglycemia is thought to be important in the development of diabetic neovascularization but the mechanisms involved remain poorly understood. Interleukin-8 (IL-8) is a leukocyte chemokine and activating agent with angiogenic properties that is present in diabetic vitreous and may play a role in diabetic vasculopathy. We studied IL-8 and monocyte chemotactic protein-1 (MCP-1) production by human retinal pigment epithelial (hRPE) cells exposed to glycated human serum albumin (GHSA). Enzyme-linked immunoassay GHSA (500 micrograms/mL)-treated hRPE cells secreted levels of IL-8 and MCP-1 detectable within 4 h and reached 26.0 +/- 1.3 and 42.2 0.4 ng/10(6) cells/mL after 24 h, respectively. Induction of IL-8 and MCP-1 by GHSA at concentrations ranging from 62.5 to 3,000 micrograms/mL exhibited dose-dependent kinetics. The GHSA-induced chemokine secretion by hRPE was almost completely inhibited by actinomycin D and cycloheximide, suggesting that de novo mRNA and protein synthesis are necessary for the GHSA-induced IL-8 and MCP-1 production. Northern blot analysis of GHSA-induced hRPE IL-8 and MCP-1 mRNA expression corresponded to the time- and dose-dependent increases measured by enzyme-linked immunosorbent assay. High concentrations of glucose (20 mM; 360 mg/dl) increased GHSA-induced hRPE IL-8 and MCP-1 secretion, whereas added insulin (0.5 ng/mL) inhibited IL-8 but not MCP-1 protein secretion and mRNA expression. GHSA also induced hRPE to secrete GRO-alpha, RANTES, and NAP-2 chemokines. GHSA induction of hRPE chemokines further suggests a role for the hRPE in leukocyte infiltration, vascular injury, and neovascularization.
authors.affiliation: Department of Ophthalmology-Kellogg Eye Center, University of Michigan, Ann Arbor 48105, USA.
authors.forename: Z M
authors.initials: ZM
authors.lastname: Bian
authors.forename: S G
authors.initials: SG
authors.lastname: Elner
authors.forename: R M
authors.initials: RM
authors.lastname: Strieter
authors.forename: M B
authors.initials: MB
authors.lastname: Glass
authors.forename: N W
authors.initials: NW
authors.lastname: Lukacs
authors.forename: S L
authors.initials: SL
authors.lastname: Kunkel
authors.forename: V M
authors.initials: VM
authors.lastname: Elner
mesh_terms: D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D018925:Chemokines / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D017127:Glycation End Products, Advanced; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D010857:Pigment Epithelium of Eye / Q000187:drug effects* / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D012709:Serum Albumin / Q000494:pharmacology*; D013268:Stimulation, Chemical; D000093423:Glycated Serum Albumin
chemical_list: D018932:Chemokine CCL2; D018925:Chemokines; D017127:Glycation End Products, Advanced; D007328:Insulin; D016209:Interleukin-8; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D012709:Serum Albumin; D003609:Dactinomycin; D003513:Cycloheximide; D005947:Glucose; D000093423:Glycated Serum Albumin