Oxygen tension modulates differentiation and primary macrophage functions in the human monocytic THP-1 cell line

PLoS One. 2013;8(1):e54926. doi: 10.1371/journal.pone.0054926. Epub 2013 Jan 23.


The human THP-1 cell line is widely used as an in vitro model system for studying macrophage differentiation and function. Conventional culture conditions for these cells consist of ambient oxygen pressure (∼20% v/v) and medium supplemented with the thiol 2-mercaptoethanol (2-ME) and serum. In consideration of the redox activities of O₂ and 2-ME, and the extensive experimental evidence supporting a role for reactive oxygen species (ROS) in the differentiation and function of macrophages, we addressed the question of whether culturing THP-1 cells under a more physiologically relevant oxygen tension (5% O₂) in the absence of 2-ME and serum would alter THP-1 cell physiology. Comparisons of cultures maintained in 18% O₂versus 5% O₂ indicated that reducing oxygen tension had no effect on the proliferation of undifferentiated THP-1 cells. However, decreasing the oxygen tension to 5% O₂ significantly increased the rate of phorbol ester-induced differentiation of THP-1 cells into macrophage-like cells as well as the metabolic activity of both undifferentiated and PMA-differentiated THP-1 cells. Removal of both 2-ME and serum from the medium decreased the proliferation of undifferentiated THP-1 cells but increased metabolic activity and the rate of differentiation under either oxygen tension. In differentiated THP-1 cells, lowering the oxygen tension to 5% O₂ decreased phagocytic activity, the constitutive release of β-hexosaminidase and LPS-induced NF-κB activation but enhanced LPS-stimulated release of cytokines. Collectively, these data demonstrate that oxygen tension influences THP-1 cell differentiation and primary macrophage functions, and suggest that culturing these cells under tightly regulated oxygen tension in the absence of exogenous reducing agent and serum is likely to provide a physiologically relevant baseline from which to study the role of the local redox environment in regulating THP-1 cell physiology.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Carcinogens / pharmacology
  • Cell Differentiation / drug effects*
  • Cell Line
  • Humans
  • Lipopolysaccharides / pharmacology
  • Macrophages / cytology
  • Macrophages / metabolism*
  • Mercaptoethanol / pharmacology
  • NF-kappa B / metabolism
  • Oxidation-Reduction / drug effects
  • Oxygen / pharmacology*
  • Reactive Oxygen Species / metabolism*
  • Tetradecanoylphorbol Acetate / pharmacology


  • Carcinogens
  • Lipopolysaccharides
  • NF-kappa B
  • Reactive Oxygen Species
  • Mercaptoethanol
  • Tetradecanoylphorbol Acetate
  • Oxygen