ANGPTL8 negatively regulates NF-κB activation by facilitating selective autophagic degradation of IKKγ

Nat Commun. 2017 Dec 18;8(1):2164. doi: 10.1038/s41467-017-02355-w.

Abstract

Excessive nuclear factor-κB (NF-κB) activation mediated by tumor necrosis factor α (TNFα) plays a critical role in inflammation. Here we demonstrate that angiopoietin-like 8 (ANGPTL8) functions as a negative feedback regulator in TNFα-triggered NF-κB activation intracellularly. Inflammatory stimuli induce ANGPTL8 expression, and knockdown or knockout of ANGPTL8 potentiates TNFα-induced NF-κB activation in vitro. Mechanistically, upon TNFα stimulation, ANGPTL8 facilitates the interaction of IKKγ with p62 via forming a complex, thus promoting the selective autophagic degradation of IKKγ. Furthermore, the N-terminal domain mediated self-oligomerization of ANGPTL8 is essential for IKKγ degradation and NF-κB activation. In vivo, circulating ANGPTL8 level is high in patients diagnosed with infectious diseases, and the ANGPTL8/p62-IKKγ axis is responsive to inflammatory stimuli in the liver of LPS-injected mice. Altogether, our study suggests the ANGPTL8/p62-IKKγ axis as a negative feedback loop that regulates NF-κB activation, and extends the role of selective autophagy in fine-tuned inflammatory responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Angiopoietin-Like Protein 8
  • Angiopoietin-like Proteins / blood
  • Angiopoietin-like Proteins / genetics
  • Angiopoietin-like Proteins / metabolism*
  • Animals
  • Autophagy*
  • Gene Expression Regulation / drug effects
  • HEK293 Cells
  • Hep G2 Cells
  • Humans
  • I-kappa B Kinase / genetics
  • I-kappa B Kinase / metabolism*
  • Inflammation / blood
  • Inflammation / genetics
  • Inflammation / metabolism
  • Interleukin-1beta / pharmacology
  • Male
  • Mice, Inbred C57BL
  • NF-kappa B / genetics
  • NF-kappa B / metabolism*
  • Peptide Hormones / blood
  • Peptide Hormones / genetics
  • Peptide Hormones / metabolism*
  • Sequestosome-1 Protein / genetics
  • Sequestosome-1 Protein / metabolism

Substances

  • ANGPTL8 protein, human
  • Angiopoietin-Like Protein 8
  • Angiopoietin-like Proteins
  • Interleukin-1beta
  • NF-kappa B
  • Peptide Hormones
  • SQSTM1 protein, human
  • Sequestosome-1 Protein
  • I-kappa B Kinase