The CD14(+/low)CD16(+) monocyte subset is more susceptible to spontaneous and oxidant-induced apoptosis than the CD14(+)CD16(-) subset

Cell Death Dis. 2010 Nov 4;1(11):e95. doi: 10.1038/cddis.2010.69.

Abstract

Human monocytes can be classified into two subsets with distinctive characteristics. In this study, we report a difference in apoptotic potential between these two subsets with CD14(+/low)CD16(+) monocytes being more susceptible than CD14(+)CD16(-) monocytes to undergo spontaneous apoptosis and apoptosis induced by reactive oxygen species (ROS). By global transcriptomic and proteomic approaches, we observed that CD14(+/low)CD16(+) monocytes expressed higher levels of pro-apoptotic genes and proteins such as TNFα, caspase 3, Bax and cytochrome c and showed more caspases 3 and 7 activities. They also exhibited greater aerobic respiration resulting in a higher production of ROS from the mitochondria. CD14(+)CD16(-) monocytes, in contrast, showed higher expression of glutathione (GSH)-metabolizing genes such as GSH peroxidase and microsomal GSH S-transferase and were more resistant to oxidative stress than CD14(+/low)CD16(+) monocytes. The apoptosis of CD14(+/low)CD16(+) monocytes was ROS dependent as reducing ROS levels significantly reduced cell death. This is the first report of a differential apoptotic propensity of human monocyte subsets, and gaining a better understanding of this process may help to provide a better understanding of the roles of these subsets during homeostasis and under pathological conditions, particularly in situations in which high levels of oxidants are present.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis*
  • Caspase 3 / metabolism
  • Caspase 7 / metabolism
  • Cytochromes c / metabolism
  • Gene Expression Profiling
  • Glutathione Peroxidase / metabolism
  • Glutathione Transferase / metabolism
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Lipopolysaccharide Receptors / metabolism*
  • Mitochondria / metabolism
  • Monocytes / classification*
  • Monocytes / immunology
  • Monocytes / metabolism
  • Oxidative Stress
  • Proteome / metabolism
  • Reactive Oxygen Species / metabolism*
  • Receptors, IgG / metabolism*
  • Tumor Necrosis Factor-alpha / metabolism
  • bcl-2-Associated X Protein / metabolism

Substances

  • Lipopolysaccharide Receptors
  • Proteome
  • Reactive Oxygen Species
  • Receptors, IgG
  • Tumor Necrosis Factor-alpha
  • bcl-2-Associated X Protein
  • Cytochromes c
  • Hydrogen Peroxide
  • Glutathione Peroxidase
  • Glutathione Transferase
  • Caspase 3
  • Caspase 7