Early NFkappaB activation is inhibited during focal cerebral ischemia in interleukin-1beta-converting enzyme deficient mice.
Our previous study demonstrated that the inhibition of interleukin-1beta (IL-1beta) reduces ischemic brain injury; however, the molecular mechanism of the action of IL-1 in cerebral ischemia is unclear. We are investigating currently the role of NFkappaB during focal cerebral ischemia, using mutant mice deficient in the interleukin-1 converting enzyme gene (ICE KO) in a middle cerebral artery occlusion (MCAO) model. Adult male ICE KO and wild-type mice (n = 120) underwent up to 24 hr of permanent MCAO. Cytoplasmic phospho-NFkappaB/p65 expression in ischemic brain was examined using Western blot analysis and immunohistochemistry. NFkappaB DNA-binding activity was detected using electrophoretic mobility shift assay (EMSA). Furthermore, ICAM-1 expression was examined in both the ICE KO and wild-type mice (WT). Western blot analysis and immunostaining showed that the level of cytosolic phosphorylated NFkappaB/p65 increased after 2 and 4 hr of MCAO in WT mice; however, NFkappaB/p65 was significantly reduced after MCAO in the ICE KO mice (P < 0.05). EMSA showed that NFkappaB DNA-binding activity increased after MCAO in WT mice; but this effect was reduced in the ICE KO mice. The number of ICAM-1-positive vessels in the ischemic hemisphere was greatly attenuated in the ICE KO mice (P < 0.05), which paralleled the results of immunohistochemistry. Our results demonstrate that NFkappaB phosphorylation is reduced in ICE KO mice, suggesting that ICE or IL-1 are involved in early NFkappaB phosphorylation. Because cerebral ischemia induced infarction is significantly reduced in ICE KO mice, we conclude that early NFkappaB phosphorylation plays a disruptive role in the ischemic process.
Huang
Feng-Peng
FP
Department of Surgery (Neurosurgery), University of Michigan, Ann Arbor, USA.
Wang
Zhi-Qiu
ZQ
Wu
Du-Chu
DC
Schielke
Gerald P
GP
Sun
Yi
Y
Yang
Guo-Yuan
GY
D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002545:Brain Ischemia / Q000503:physiopathology*; D020170:Caspase 1 / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D007150:Immunohistochemistry; D020244:Infarction, Middle Cerebral Artery / Q000235:genetics / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D010766:Phosphorylation; D021381:Protein Transport / Q000502:physiology
D016328:NF-kappa B; D018799:Intercellular Adhesion Molecule-1; D020170:Caspase 1