DeSUMOylation of MKK7 kinase by the SUMO2/3 protease SENP3 potentiates lipopolysaccharide-induced inflammatory signaling in macrophages

J Biol Chem. 2018 Mar 16;293(11):3965-3980. doi: 10.1074/jbc.M117.816769. Epub 2018 Jan 19.

Abstract

Protein SUMOylation has been reported to play a role in innate immune response, but the enzymes, substrates, and consequences of the specific inflammatory signaling events are largely unknown. Reactive oxygen species (ROS) are abundantly produced during macrophage activation and required for Toll-like receptor 4 (TLR4)-mediated inflammatory signaling. Previously, we demonstrated that SENP3 is a redox-sensitive SUMO2/3 protease. To explore any links between reversible SUMOylation and ROS-related inflammatory signaling in macrophage activation, we generated mice with Senp3 conditional knock-out in myeloid cells. In bacterial lipopolysaccharide (LPS)-induced in vitro and in vivo inflammation models, we found that SENP3 deficiency markedly compromises the activation of TLR4 inflammatory signaling and the production of proinflammatory cytokines in macrophages exposed to LPS. Moreover, Senp3 conditional knock-out mice were significantly less susceptible to septic shock. Of note, SENP3 deficiency was associated with impairment in JNK phosphorylation. We found that MKK7, which selectively phosphorylates JNK, is a SENP3 substrate and that SENP3-mediated deSUMOylation of MKK7 may favor its binding to JNK. Importantly, ROS-dependent SENP3 accumulation and MKK7 deSUMOylation rapidly occurred after LPS stimulation. In conclusion, our findings indicate that SENP3 potentiates LPS-induced TLR4 signaling via deSUMOylation of MKK7 leading to enhancement in JNK phosphorylation and the downstream events. Therefore this work provides novel mechanistic insights into redox regulation of innate immune responses.

Keywords: ROS; SENP3; c-Jun N-terminal kinase (JNK); inflammation; innate immunity; macrophage; sumoylation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Cysteine Endopeptidases
  • Cytokines / metabolism
  • Immunity, Innate / immunology*
  • Inflammation / chemically induced
  • Inflammation / immunology
  • Inflammation / metabolism
  • Inflammation / pathology*
  • Lipopolysaccharides / toxicity*
  • MAP Kinase Kinase 7 / genetics
  • MAP Kinase Kinase 7 / metabolism*
  • Macrophages / drug effects
  • Macrophages / immunology
  • Macrophages / pathology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Peptide Hydrolases / physiology*
  • Reactive Oxygen Species / metabolism
  • Signal Transduction
  • Small Ubiquitin-Related Modifier Proteins / genetics
  • Small Ubiquitin-Related Modifier Proteins / metabolism*
  • Sumoylation

Substances

  • Cytokines
  • Lipopolysaccharides
  • Reactive Oxygen Species
  • Small Ubiquitin-Related Modifier Proteins
  • MAP Kinase Kinase 7
  • Map2k7 protein, mouse
  • Peptide Hydrolases
  • Cysteine Endopeptidases
  • Senp3 protein, mouse