Strong neuroprotection by inhibition of NF-κB after neonatal hypoxia-ischemia involves apoptotic mechanisms but is independent of Cytokines
Strong neuroprotection by inhibition of NF-κB after neonatal hypoxia-ischemia involves apoptotic mechanisms but is independent of Cytokines
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DOI：
10.1161/strokeaha.107.504175
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发表时间：
2008-07-01
期刊：
影响因子：
8.3
通讯作者：
Kavelaars, Annemieke
中科院分区：
文献类型：
--
作者：
Nijboer, Cora H. A.;Heijnen, Cobi J.;Kavelaars, Annemieke
背景和目的--兴奋性毒性、炎症和细胞凋亡通路之间的相互作用决定了缺氧缺血性脑损伤的结局。转录因子NF-kappa B被认为通过刺激细胞因子的产生来加强脑损伤。也有证据表明，核因子-kappaB的活性是神经元生存所必需的。我们使用核因子-kappa B抑制剂NBD，结合TAT促进脑摄取，以确定核因子-kappa B抑制在新生儿缺氧缺血(HI)中的神经保护作用，并确定其在脑组织炎症和损伤中的作用。方法采用单侧颈动脉结扎和缺氧诱导新生大鼠脑损伤模型，免疫组织化学方法检测脑组织中核因子-kappaB的活性，EMSA分析其活性。我们用Western blotting分析了细胞因子的mRNA水平和凋亡通路的激活。结果：TAT-NBD抑制大鼠脑内核因子-kappaB活性具有明显的神经保护作用，脑损伤减轻80%以上，治疗时间窗至少为6h。与先前的建议相反，TAT-NBD的保护作用不涉及抑制HI后早期细胞因子的上调。此外，抑制核转录因子-kappaB可阻止HI诱导的p53的表达上调和核及线粒体的积聚，阻止线粒体细胞色素-c的释放和caspase-3的激活。最后，TAT-NBD可以直接增加神经元的存活率，因为TAT-NBD足以抑制神经细胞系的死亡。结论抑制核因子-kappaB具有较强的神经保护作用，其机制与下调细胞凋亡分子有关，但不依赖于抑制细胞因子的产生。
Background and Purpose - Interactions between excitotoxic, inflammatory, and apoptotic pathways determine outcome in hypoxic-ischemic brain damage. The transcription factor NF-kappa B has been suggested to enhance brain damage via stimulation of cytokine production. There is also evidence that NF-kappa B activity is required for neuronal survival. We used the NF-kappa B inhibitor NBD, coupled to TAT to facilitate cerebral uptake, to determine the neuroprotective capacity of NF-kappa B inhibition in neonatal hypoxia-ischemia ( HI) and to identify its contribution to cerebral inflammation and damage.Methods - Brain damage was induced in neonatal rats by unilateral carotid artery occlusion and hypoxia and analyzed immunohistochemically; NF-kappa B activity was analyzed by EMSA. We analyzed cytokine mRNA levels and activation of apoptotic pathways by Western blotting. In vitro effects of TAT-NBD were determined in a neuronal cell line.Results - Inhibition of cerebral NF-kappa B activity by TAT-NBD had a significant neuroprotective effect; brain damage was reduced by more than 80% with a therapeutic window of at least 6 hours. In contrast to earlier suggestions, the protective effect of TAT-NBD did not involve suppression of early cytokine upregulation after HI. Moreover, NF-kappa B inhibition prevented HI-induced upregulation and nuclear as well as mitochondrial accumulation of p53, prevented mitochondrial cytochrome-c release and activation of caspase-3. Finally, TAT-NBD could directly increase neuronal survival because TAT-NBD was sufficient to inhibit death in a neuronal cell line. A nonactive mutant peptide did not have any effect.Conclusions - Inhibition of NF-kappa B has strong neuroprotective effects that involve downregulation of apoptotic molecules but are independent of inhibition of cytokine production.