title: Adrenomedullin signals through NF-kappaB in epithelial cells.
abstract: Adrenomedullin is a peptide found in a variety of cells and tissues and involved in a multitude of biological processes. Recently, adrenomedullin has been identified as a host defense peptide and as such it plays a role in the inflammatory response. The transcription factor NF-kappaB is a major regulator of genes involved in the inflammatory response and the aim of this study was to determine whether NF-kappaB played a role in the inflammatory process triggered by adrenomedullin. Skin epithelial cells (HaCaTs) were used as our model in vitro. Western blot analysis from adrenomedullin-stimulated HaCaT cells revealed a rapid degradation of NF-kappaB inhibitor alpha and beta followed by the translocation of free NF-kappaB to the nucleus, where it was detected by Texas Red immunostaining after incubation with adrenomedullin for 15 min. Electromobility shift assay showed that NF-kappaB present in the nucleus was active, since it bound to a probe containing an NF-kappaB binding site. Supershift assays indicated that p50 and p65, members of the NF-kappaB family, were both part of the NF-kappaB dimmers involved in adrenomedullin cell signaling. HaCaTs secreted interleukin-6 in response to AM, which was significantly attenuated by the NF-kappaB inhibitor SN-50. Taken together, the data lend support for an immunoregulatory role for AM.
authors.affiliation: Molecular Signalling Group, Clinical and Diagnostic Oral Sciences, Barts & the London, Queen Mary University of London, 2 Newark street, London E1 2AD, UK.
authors.forename: Olga
authors.initials: O
authors.lastname: Pleguezuelos
authors.forename: Eleni
authors.initials: E
authors.lastname: Hagi-Pavli
authors.forename: George
authors.initials: G
authors.lastname: Crowther
authors.forename: Supriya
authors.initials: S
authors.lastname: Kapas
mesh_terms: D053607:Adrenomedullin; D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D020672:I-kappa B Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000378:metabolism; D015603:Keratinocytes / Q000187:drug effects; D016328:NF-kappa B / Q000378:metabolism*; D010455:Peptides / Q000502:physiology*; D021381:Protein Transport; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D020672:I-kappa B Proteins; D015850:Interleukin-6; D016328:NF-kappa B; D010455:Peptides; D053607:Adrenomedullin