Tumor necrosis factor-alpha activates the human prolactin gene promoter via nuclear factor-kappaB signaling

Sönke Friedrichsen, Claire V Harper, Sabrina Semprini, Michael Wilding, Antony D Adamson, Dave G Spiller, Glyn Nelson, John J Mullins, Michael R H White, Julian R E Davis

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Pituitary function has been shown to be regulated by an increasing number of intrapituitary factors, including cytokines. Here we show that the important cytokine TNF-alpha activates prolactin gene transcription in pituitary GH3 cells stably expressing luciferase under control of 5 kb of the human prolactin promoter. Similar regulation of the endogenous rat prolactin gene by TNF-alpha in GH3 cells was confirmed using real-time PCR. Luminescence microscopy revealed heterogeneous dynamic response patterns of promoter activity in individual cells. In GH3 cells treated with TNF-alpha, Western blot analysis showed rapid inhibitory protein kappaB (IkappaBalpha) degradation and phosphorylation of p65. Confocal microscopy of cells expressing fluorescence-labeled p65 and IkappaBalpha fusion proteins showed transient cytoplasmic-nuclear translocation and subsequent oscillations in p65 localization and confirmed IkappaBalpha degradation. This was associated with increased nuclear factor kappaB (NF-kappaB)-mediated transcription from an NF-kappaB-responsive luciferase reporter construct. Disruption of NF-kappaB signaling by expression of dominant-negative variants of IkappaB kinases or truncated IkappaBalpha abolished TNF-alpha activation of the prolactin promoter, suggesting that this effect was mediated by NF-kappaB. TNF-alpha signaling was found to interact with other endocrine signals to regulate prolactin gene expression and is likely to be a major paracrine modulator of lactotroph function.

Original languageEnglish
Pages (from-to)773-81
Number of pages9
JournalEndocrinology
Volume147
Issue number2
DOIs
Publication statusPublished - 1 Feb 2006

Keywords

  • Animals
  • Cell Line, Tumor
  • Gene Expression Regulation/physiology
  • Genes, Reporter
  • Humans
  • NF-kappa B/metabolism
  • Pituitary Gland/cytology
  • Prolactin/genetics
  • Promoter Regions, Genetic/genetics
  • Rats
  • Signal Transduction/physiology
  • Transfection
  • Tumor Necrosis Factor-alpha/physiology

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    Friedrichsen, S., Harper, C. V., Semprini, S., Wilding, M., Adamson, A. D., Spiller, D. G., Nelson, G., Mullins, J. J., White, M. R. H., & Davis, J. R. E. (2006). Tumor necrosis factor-alpha activates the human prolactin gene promoter via nuclear factor-kappaB signaling. Endocrinology, 147(2), 773-81. https://doi.org/10.1210/en.2005-0967