STAT1- and NFAT-independent amplification of purinoceptor function integrates cellular senescence with interleukin-6 production in preadipocytes

Yasser Majeed (Lead Author), Aisha Y. Madani, Ahmed I. Altamimi, Raphael Courjaret, Muneera Vakayil, Samuel J. Fountain, Khaled Machaca, Nayef A. Mazloum

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Abstract

Background and Purpose: Senescent preadipocytes promote adipose tissue dysfunction by secreting pro-inflammatory factors, although little is known about the mechanisms regulating their production. We investigated if up-regulated purinoceptor function sensitizes senescent preadipocytes to cognate agonists and how such sensitization regulates inflammation. Experimental Approach: Etoposide was used to trigger senescence in 3T3-L1 preadipocytes. CRISPR/Cas9 technology or pharmacology allowed studies of transcription factor function. Fura-2 imaging was used for calcium measurements. Interleukin-6 levels were quantified using quantitative PCR and ELISA. Specific agonists and antagonists supported studies of purinoceptor coupling to interleukin-6 production. Experiments in MS1 VEGF angiosarcoma cells and adipose tissue samples from obese mice complemented preadipocyte experiments. Key Results: DNA damage-induced senescence up-regulated purinoceptor expression levels in preadipocytes and MS1 VEGF angiosarcoma cells. ATP-evoked Ca 2+ release was potentiated in senescent preadipocytes. ATP enhanced interleukin-6 production, an effect mimicked by ADP but not UTP, in a calcium-independent manner. Senescence-associated up-regulation and activation of the adenosine A 3 receptor also enhanced interleukin-6 production. However, nucleotide hydrolysis was not essential because exposure to ATPγS also enhanced interleukin-6 secretion. Pharmacological experiments suggested coupling of P2X ion channels and P2Y 12–P2Y 13 receptors to downstream interleukin-6 production. Interleukin-6 signalling exacerbated inflammation during senescence and compromised adipogenesis. Conclusions and Implications: We report a previously uncharacterized link between cellular senescence and purinergic signalling in preadipocytes and endothelial cancer cells, raising the possibility that up-regulated purinoceptors play key modulatory roles in senescence-associated conditions like obesity and cancer. There is potential for exploitation of specific purinoceptor antagonists as therapeutics in inflammatory disorders.

Original languageEnglish
Pages (from-to)609-627
Number of pages19
JournalBritish Journal of Pharmacology
Volume180
Issue number5
Early online date2 Nov 2022
DOIs
Publication statusPublished - Mar 2023

Keywords

  • Adora3
  • DNA damage
  • inflammation
  • interleukin-6
  • purinergic signalling
  • senescence

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