Background: Inflammation is a key element in the pathophysiology of cerebral ischemia. This study investigated the role of N-Myc downstream-regulated gene-2 in nuclear transcription factor κB-mediated inflammation in ischemia models.
Methods: Mice (n = 6 to 12) with or without nuclear transcription factor κB inhibitor pyrrolidinedithiocarbamate pretreatment were subjected to global cerebral ischemia for 20 min. Pure astrocyte cultures or astrocyte-neuron cocultures (n = 6) with or without pyrrolidinedithiocarbamate pretreatment were exposed to oxygen-glucose deprivation for 4 h or 2 h. Astrocytic nuclear transcription factor κB and N-Myc downstream-regulated gene-2 expression, proinflammatory cytokine secretion, neuronal apoptosis and survival, and memory function were analyzed at different time points after reperfusion or reoxygenation. Proinflammatory cytokine secretion was also studied in lentivirus-transfected astrocyte lines after reoxygenation.
Results: Astrocytic nuclear transcription factor κB and N-Myc downstream-regulated gene-2 expression and proinflammatory cytokine secretion increased after reperfusion or reoxygenation. Pyrrolidinedithiocarbamate pretreatment significantly reduced N-Myc downstream-regulated gene-2 expression and proinflammatory cytokine secretion in vivo and in vitro, reduced neuronal apoptosis induced by global cerebral ischemia/reperfusion (from 65 ± 4% to 47 ± 4%, P = 0.0375) and oxygen-glucose deprivation/reoxygenation (from 45.6 ± 0.2% to 22.0 ± 4.0%, P < 0.001), and improved memory function in comparison to vehicle-treated control animals subjected to global cerebral ischemia/reperfusion. N-Myc downstream-regulated gene-2 lentiviral knockdown reduced the oxygen-glucose deprivation-induced secretion of proinflammatory cytokines.
Conclusions: Astrocytic N-Myc downstream-regulated gene-2 is up-regulated after cerebral ischemia and is involved in nuclear transcription factor κB-mediated inflammation. Pyrrolidinedithiocarbamate alleviates ischemia-induced neuronal injury and hippocampal-dependent cognitive impairment by inhibiting increases in N-Myc downstream-regulated gene-2 expression and N-Myc downstream-regulated gene-2-mediated inflammation.