Phosphoinositol 3-phosphate acts as a timer for reactive oxygen species production in the phagosome

J Leukoc Biol. 2017 May;101(5):1155-1168. doi: 10.1189/jlb.1A0716-305R. Epub 2017 Jan 17.

Abstract

Production of reactive oxygen species (ROS) in the phagosome by the NADPH oxidase is critical for mammalian immune defense against microbial infections and phosphoinositides are important regulators in this process. Phosphoinositol 3-phosphate (PI(3)P) regulates ROS production at the phagosome via p40phox by an unknown mechanism. This study tested the hypothesis that PI(3)P controls ROS production by regulating the presence of p40phox and p67phox at the phagosomal membrane. Pharmacologic inhibition of PI(3)P synthesis at the phagosome decreased the ROS production both in differentiated PLB-985 cells and human neutrophils. It also releases p67phox, the key cytosolic subunit of the oxidase, and p40phox from the phagosome. The knockdown of the PI(3)P phosphatase MTM1 or Rubicon or both increases the level of PI(3)P at the phagosome. That increase enhances ROS production inside the phagosome and triggers an extended accumulation of p67phox at the phagosome. Furthermore, the overexpression of MTM1 at the phagosomal membrane induces the disappearance of PI(3)P from the phagosome and prevents sustained ROS production. In conclusion, PI(3)P, indeed, regulates ROS production by maintaining p40phox and p67phox at the phagosomal membrane.

Keywords: NADPH oxidase; live imaging; phagocytosis.

MeSH terms

  • Autophagy-Related Proteins
  • Cell Line, Tumor
  • Gene Expression Regulation
  • Humans
  • Intracellular Membranes / drug effects
  • Intracellular Membranes / immunology
  • Intracellular Membranes / metabolism
  • Intracellular Signaling Peptides and Proteins / antagonists & inhibitors
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / immunology
  • Monocytes / cytology
  • Monocytes / drug effects
  • Monocytes / immunology*
  • NADPH Oxidases / genetics
  • NADPH Oxidases / immunology*
  • Neutrophils / cytology
  • Neutrophils / drug effects
  • Neutrophils / immunology*
  • Phagosomes / drug effects
  • Phagosomes / immunology*
  • Phagosomes / metabolism
  • Phosphatidylinositol Phosphates / immunology*
  • Phosphatidylinositol Phosphates / metabolism
  • Phosphatidylinositol Phosphates / pharmacology
  • Phosphoproteins / genetics
  • Phosphoproteins / immunology*
  • Primary Cell Culture
  • Protein Tyrosine Phosphatases, Non-Receptor / antagonists & inhibitors
  • Protein Tyrosine Phosphatases, Non-Receptor / genetics
  • Protein Tyrosine Phosphatases, Non-Receptor / immunology
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Reactive Oxygen Species / immunology
  • Reactive Oxygen Species / metabolism
  • Signal Transduction

Substances

  • Autophagy-Related Proteins
  • Intracellular Signaling Peptides and Proteins
  • Phosphatidylinositol Phosphates
  • Phosphoproteins
  • RNA, Small Interfering
  • RUBCN protein, human
  • Reactive Oxygen Species
  • neutrophil cytosol factor 67K
  • phosphatidylinositol 3-phosphate
  • NADPH Oxidases
  • NCF4 protein, human
  • Protein Tyrosine Phosphatases, Non-Receptor
  • myotubularin