BACKGROUND - The purpose of the current study was to evaluate the role of bioluminescence imaging (BLI) in the determination of nuclear factor (NF)-kappaB activation in cardiac allograft rejection and ischemia-reperfusion injury.
METHODS - To visualize NF-kappaB activation, luciferase transgenic mice under the control of a mouse NF-kappaB promoter (NF-kappaB-Luc) were used as donors or recipients of cardiac grafts. Alternatively, NF-kappaB-Luc spleen cells were adoptively transferred into Rag2 -/- mice with or without cardiac allografts. BLI was performed posttransplantation to detect luciferase activity that represents NF-kappaB activation.
RESULTS - The results show that luciferase activity was significantly increased in the cardiac allografts when NF-kappaB-Luc mice were used as recipients as well as donors. Luciferase activity was also elevated in the wild-type cardiac allografts in Rag2 -/- mice that were transferred with NF-kappaB-Luc spleen cells. CD154 monoclonal antibody (mAb) therapy inhibited luciferase activity and induced long-term survival of cardiac allografts. toll-like receptor-9 ligand, CpG DNA, enhanced luciferase activity and abrogated tolerance induction by CD154 mAb. Luciferase activity was also increased in ischemia-reperfusion injury of the cardiac grafts.
CONCLUSION - BLI using Luc-NF-kappaB mice is a noninvasive approach to visualize the activation of NF-kappaB signaling in mouse cardiac allograft rejection and ischemia-reperfusion injury. CD154 mAb can inhibit NF-kappaB activation, which is reversed by toll-like receptor engagement.