Analysis of Interleukin-1β-induced Cell Signaling Activation in Rat Hippocampus following Exposure to Gamma Irradiation

• Published in: The Journal of biological chemistry Vol. 278; no. 51; p. 51075
• Main Authors: Aileen M. Lynch, Michelle Moore, Sarah Craig, Peter E. Lonergan, Darren S. Martin, Marina A. Lynch
• Format: Journal Article
• Language: English
• Published: American Society for Biochemistry and Molecular Biology 19-12-2003
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M307970200

Among the many reported effects of irradiation in cells is activation of the stress-activated protein kinase, c-Jun N-terminal
kinase (JNK), which has been shown to result in apoptotic cell death. The trigger that leads to JNK activation has not been
identified, although, in rat hippocampus at least, irradiation-induced apoptosis has been coupled with increased accumulation
of reactive oxygen species (ROS). Significantly, irradiation-induced changes in hippocampus are abrogated by treatment of
rats with the polyunsaturated fatty acid, eicosapentaenoic acid (EPA). A close coupling between ROS accumulation and concentration
of the pro-inflammatory cytokine, interleukin-1β (IL-1β) in hippocampus has been reported, and the evidence suggests that
IL-1β may be responsible for the enhanced ROS production. Here we set out to assess the possibility that whole body γ-irradiation
increases IL-1β concentration in hippocampus and to investigate the consequences of such a change. We present evidence that
reveals that the irradiation-induced increase in IL-1β concentration in hippocampus is accompanied by increased expression
of IL-1 type I receptor and IL-1 accessory protein and increased activation of IL-1 receptor-activated kinase. These changes,
which were coupled with increased activation of JNK and evidence of apoptotic cell death, were absent in hippocampus of rats
that received EPA treatment. Significantly, EPA treatment enhanced hippocampal IL-10 concentration that was inversely correlated
with IL-1β concentration. The data are consistent with the idea that EPA exerts anti-inflammatory and neuroprotective effects
in the central nervous system.