Carret-Rebillat Anne-Sophie, Pace Clarisse, Gourmaud Sarah, Ravasi Laura, Montagne-Stora Samantha, Longueville Sophie, Tible Marion, Sudol Erika, Chang Raymond Chuen-Chung, Paquet Claire, Mouton-Liger François, Hugon Jacques
Inserm UMR-S942, Lariboisiere Hospital, Paris, France.
In vivo preclinical imaging facility, IFR 114 - University of Lille, Nord of France, CHU Lille, France.
Sci Rep. 2015 Feb 17;5:8489. doi: 10.1038/srep08489.
Alzheimer's disease (AD) is a neurodegenerative disorder, marked by senile plaques composed of amyloid-β (Aβ) peptide, neurofibrillary tangles, neuronal loss and neuroinflammation. Previous works have suggested that systemic inflammation could contribute to neuroinflammation and enhanced Aβ cerebral concentrations. The molecular pathways leading to these events are not fully understood. PKR is a pro-apoptotic kinase that can trigger inflammation and accumulates in the brain and cerebrospinal fluid of AD patients. The goal of the present study was to assess if LPS-induced neuroinflammation and Aβ production could be altered by genetic PKR down regulation. The results show that, in the hippocampus of LPS-injected wild type mice, neuroinflammation, cytokine release and Aβ production are significantly increased and not in LPS-treated PKR knock-out mice. In addition BACE1 and activated STAT3 levels, a putative transcriptional regulator of BACE1, were not found increased in the brain of PKR knock-out mice as observed in wild type mice. Using PET imaging, the decrease of hippocampal metabolism induced by systemic LPS was not observed in LPS-treated PKR knock-out mice. Altogether, these findings demonstrate that PKR plays a major role in brain changes induced by LPS and could be a valid target to modulate neuroinflammation and Aβ production.
阿尔茨海默病(AD)是一种神经退行性疾病,其特征为存在由β-淀粉样蛋白(Aβ)肽组成的老年斑、神经原纤维缠结、神经元丢失和神经炎症。先前的研究表明,全身炎症可能导致神经炎症并提高大脑中Aβ的浓度。导致这些事件的分子途径尚未完全明确。PKR是一种促凋亡激酶,可引发炎症,且在AD患者的大脑和脑脊液中蓄积。本研究的目的是评估基因敲低PKR是否会改变脂多糖(LPS)诱导的神经炎症和Aβ生成。结果显示,在注射LPS的野生型小鼠海马体中,神经炎症、细胞因子释放和Aβ生成显著增加,而在LPS处理的PKR基因敲除小鼠中则未出现这种情况。此外,与野生型小鼠不同,在PKR基因敲除小鼠大脑中未发现β-分泌酶1(BACE1)水平及作为BACE1假定转录调节因子的活化信号转导和转录激活因子3(STAT3)水平升高。利用正电子发射断层扫描(PET)成像发现,LPS处理的PKR基因敲除小鼠未出现全身性LPS诱导的海马体代谢降低。总之,这些发现表明PKR在LPS诱导的大脑变化中起主要作用,可能是调节神经炎症和Aβ生成的有效靶点。