Pannexin-1 limits the production of proinflammatory cytokines during necroptosis

EMBO Rep. 2019 Oct 4;20(10):e47840. doi: 10.15252/embr.201947840. Epub 2019 Aug 14.

Abstract

The activation of mixed lineage kinase-like (MLKL) by receptor-interacting protein kinase-3 (RIPK3) controls the execution of necroptosis, a regulated form of necrosis that occurs in apoptosis-deficient conditions. Active oligomerized MLKL triggers the exposure of phosphatidylserine residues on the cell surface and disrupts the plasma membrane integrity by forming lytic pores. MLKL also governs endosomal trafficking and biogenesis of small extracellular vesicles as well as the production of proinflammatory cytokines during the early steps of necroptosis; however, the molecular basis continues to be elucidated. Here, we find that MLKL oligomers activate Pannexin-1 (PANX1) channels, concomitantly to the loss of phosphatidylserine asymmetry. This plasma membrane "leakiness" requires the small GTPase RAB27A and RAB27B isoforms, which regulate intracellular vesicle trafficking, docking, and fusion with the plasma membrane. Although cells in which PANX1 is silenced or inhibited normally undergo necroptotic death, they display enhanced production of cytokines such as interleukin-8, indicating that PANX1 may tamper with inflammation. These data identify a novel signaling nexus between MLKL, RAB27, and PANX1 and propose ways to interfere with inflammation associated with necroptosis.

Keywords: MLKL; Pannexin-1; cytokines; inflammation; necroptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Membrane / metabolism
  • Cell Membrane Permeability
  • Cell Survival
  • Connexins / metabolism*
  • Cytokines / metabolism*
  • Gene Silencing
  • HT29 Cells
  • Humans
  • Inflammation Mediators / metabolism*
  • Necroptosis*
  • Nerve Tissue Proteins / metabolism*
  • Protein Kinases / metabolism
  • Protein Multimerization
  • Transport Vesicles / metabolism

Substances

  • Connexins
  • Cytokines
  • Inflammation Mediators
  • Nerve Tissue Proteins
  • PANX1 protein, human
  • MLKL protein, human
  • Protein Kinases