Adrenomedullin signals through NF-kappaB in epithelial cells.
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.
Pleguezuelos
Olga
O
Molecular Signalling Group, Clinical and Diagnostic Oral Sciences, Barts & the London, Queen Mary University of London, 2 Newark street, London E1 2AD, UK.
Hagi-Pavli
Eleni
E
Crowther
George
G
Kapas
Supriya
S
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*
D020672:I-kappa B Proteins; D015850:Interleukin-6; D016328:NF-kappa B; D010455:Peptides; D053607:Adrenomedullin