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Ionizing Radiation Potentiates the Induction of Nitric Oxide Synthase by Interferon‐γ and/or Lipopolysaccharide in Murine Macrophage Cell Lines: Role of Tumor Necrosis Factor‐α
Author(s) -
MCKINNEY LESLIE C.,
AQUILLA ELIZABETH M.,
COFFIN DEBORAH,
WINK DAVID A.,
VODOVOTZ YORAM
Publication year - 2000
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2000.tb06176.x
Subject(s) - nitric oxide , nitric oxide synthase , lipopolysaccharide , priming (agriculture) , tumor necrosis factor alpha , macrophage , cytokine , microbiology and biotechnology , chemistry , cell culture , interferon , biology , immunology , biochemistry , in vitro , botany , germination , genetics , organic chemistry
A bstract : Macrophages respond to infection or injury by changing from a “resting” cellular phenotype to an “activated” state defined by the expression of various cytotoxic effector functions. Regulation of the transition from a resting to an activated state is effected by cytokine and/or pathogenic signals. Some signals do not directly induce activation, but instead “prime” the macrophage to respond more vigorously to a second signal. One example of this priming phenomenon involves induction of nitric oxide (NO) synthesis by the enzyme nitric oxide synthase (NOS2). Our experiments indicate that low doses (1–5 Gy) of ionizing radiation can enhance the induction of enzymatically active NOS2 by IFN‐γ or LPS in J774.1 and RAW264.7 murine macrophage cell lines. Radiation alone did not produce this induction, rather, it was effective as a priming signal; cells exposed to radiation produced more NO when a second signal, either IFN‐γ or LPS, was applied 24 h later.