title: The effect of 17beta-estradiol on IL-6 secretion and NF-kappaB DNA-binding activity in human retinal pigment epithelial cells.
abstract: Toll-like receptors (TLRs) and inflammatory cascades participate in the pathology of age-related macular degeneration (AMD). The effect of estrogens on the development of AMD is poorly understood, although many studies indicate that these compounds can modulate inflammatory responses. In this study, we investigated the regulatory role of TLR agonists and 17beta-estradiol (E(2)) on IL-6 expression and NF-kappaB DNA-binding activity in human retinal pigment epithelial cells (ARPE-19). The inflammatory response of ARPE-19 cells to various TLR agonists, e.g. Pam, zymosan, flagellin, SLTA and lipopolysaccharide (LPS) exposures were examined via the secretion of IL-6 cytokine as analyzed by ELISA. In addition, the IL-6 responses to the estrogen-receptor agonist, E(2), and to the estrogen-receptor antagonist ICI 182.780 as well as to the NF-kappaB inhibitor helenalin were compared. The DNA-binding activity of NF-kappaB transcription factor of nuclear cell extracts was analyzed by the gel mobility shift assay (EMSA). TLR4 gene expression was studied by quantitave PCR. The TLR4 agonist, LPS, caused a clear IL-6 response that was attenuated by E(2) in ARPE-19-cells. The anti-inflammatory properties of E(2) were mediated through estrogen receptors and were associated with decreased NF-kappaB DNA-binding activity. The level of TLR4 gene expression was not affected by LPS exposure. Our results indicate that IL-6 expression is regulated through NF-kappaB transcription factor and stereoid-receptor signalling pathways in ARPE-19 cells.
authors.affiliation: Department of Ophthalmology, University of Kuopio, Kuopio, Finland.
authors.forename: Tuomas
authors.initials: T
authors.lastname: Paimela
authors.forename: Tuomas
authors.initials: T
authors.lastname: Ryhänen
authors.forename: Eliisa
authors.initials: E
authors.lastname: Mannermaa
authors.forename: Johanna
authors.initials: J
authors.lastname: Ojala
authors.forename: Giedrius
authors.initials: G
authors.lastname: Kalesnykas
authors.forename: Antero
authors.initials: A
authors.lastname: Salminen
authors.forename: Kai
authors.initials: K
authors.lastname: Kaarniranta
mesh_terms: D002460:Cell Line; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000378:metabolism*; D006801:Humans; D007249:Inflammation; D015850:Interleukin-6 / Q000276:immunology / Q000378:metabolism*; D016328:NF-kappa B / Q000276:immunology / Q000378:metabolism*; D010857:Pigment Epithelium of Eye / Q000276:immunology / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051197:Toll-Like Receptor 4 / Q000819:agonists / Q000276:immunology / Q000378:metabolism*; D051193:Toll-Like Receptors / Q000276:immunology / Q000378:metabolism
chemical_list: D016207:Cytokines; D015850:Interleukin-6; D016328:NF-kappa B; D011960:Receptors, Estrogen; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D004958:Estradiol; D004247:DNA