Lei Bo, Liu Jiaxin, Yao Zhihui, Xiao Yan, Zhang Xiaoling, Zhang Yueting, Xu Jianguo
Department of Neurosurgery, West-China Hospital, Sichuan University, Chengdu, China.
Department of Neurosurgery, People's Hospital of Leshan, Leshan, China.
Front Cell Neurosci. 2021 Apr 16;15:653881. doi: 10.3389/fncel.2021.653881. eCollection 2021.
Alzheimer's disease (AD) is a common neurodegenerative disorder that places a heavy burden on patients and society. Hippocampal neuronal loss is a hallmark of AD progression. Therefore, understanding the mechanism underlying hippocampal neuronal death would be of great importance for the diagnosis and treatment of AD. This study aimed to explore the molecular mechanism which nuclear factor kappa β (NF-κB) promotes hippocampal neuronal oxidative stress and pyroptosis in AD. We collected serum samples from 101 healthy elderly people and 112 patients with AD at the Affiliated Hospital of Kunming University of Science and Technology between January 2017 and January 2020. Commercially available human hippocampal neurons (HHNs) were used to establish an AD model (AD-HHN) following Aβ25-35 treatment. The mRNA expression levels of NF-κB and pyroptosis markers [NLR family pyrin domain-containing 3, caspase-1, interleukin (IL)-1β, and interleukin-18] mRNA and the expression level of miR-146a-5p in the serum samples of patients with AD and AD-HHNs were determined by quantitative reverse transcription polymerase chain reaction. Oxidative stress indices (reactive oxygen species, malondialdehyde, nicotinamide adenine dinucleotide phosphate, superoxide dismutase, glutathione, and catalase) were measured by Enzyme-Linked Immunosorbent Assay (ELISA). The expression of proteins [NF-κB, TP53-induced glycolysis and apoptosis regulator (TIGAR), and pyroptosis markers] was tested by western blotting. The relationship between miR-146a-5p and TIGAR was investigated using a dual luciferase reporter gene assay. We found that NF-κB and miR-146a-5p were highly expressed, while TIGAR was low expressed in patients with AD and AD-HHNs. In addition, there was a significant positive correlation between the expression levels of NF-κB and miR-146a-5p, but a negative correlation between NF-κB mRNA and TIGAR mRNA in patients with AD, as well as miR-146a-5p and TIGAR mRNA in patients with AD. In AD-HNNs, miR-146a-5p targeted and downregulated the expression of TIGAR. Knockdown of NF-κB or overexpression of TIGAR markedly attenuated oxidative stress and pyroptosis in AD-HHNs, while concurrent overexpression of miR-146a-5p inhibited these effects. In conclusion, NF-κB-induced upregulation of miR-146a-5p promoted oxidative stress and pyroptosis in AD-HNNs by targeting TIGAR.
阿尔茨海默病（AD）是一种常见的神经退行性疾病，给患者和社会带来了沉重负担。海马神经元丢失是AD进展的一个标志。因此，了解海马神经元死亡的潜在机制对于AD的诊断和治疗至关重要。本研究旨在探讨核因子κB（NF-κB）促进AD中海马神经元氧化应激和焦亡的分子机制。我们于2017年1月至2020年1月在昆明理工大学附属医院收集了101名健康老年人和112名AD患者的血清样本。使用市售的人海马神经元（HHNs）在Aβ25-35处理后建立AD模型（AD-HHN）。通过定量逆转录聚合酶链反应测定AD患者血清样本和AD-HHNs中NF-κB和焦亡标志物[含NLR家族吡啶结构域3、半胱天冬酶-1、白细胞介素（IL）-1β和白细胞介素-18]mRNA的表达水平以及miR-146a-5p的表达水平。通过酶联免疫吸附测定（ELISA）测量氧化应激指标（活性氧、丙二醛、烟酰胺腺嘌呤二核苷酸磷酸、超氧化物歧化酶、谷胱甘肽和过氧化氢酶）。通过蛋白质印迹法检测蛋白质[NF-κB、TP53诱导的糖酵解和凋亡调节因子（TIGAR）以及焦亡标志物]的表达。使用双荧光素酶报告基因测定法研究miR-146a-5p与TIGAR之间的关系。我们发现，在AD患者和AD-HHNs中，NF-κB和miR-146a-5p高表达，而TIGAR低表达。此外，AD患者中NF-κB与miR-146a-5p的表达水平之间存在显著正相关，但NF-κB mRNA与TIGAR mRNA之间以及AD患者中miR-146a-5p与TIGAR mRNA之间存在负相关。在AD-HNNs中，miR-146a-5p靶向并下调TIGAR的表达。敲低NF-κB或过表达TIGAR可显著减轻AD-HHNs中的氧化应激和焦亡，而同时过表达miR-146a-5p则抑制这些作用。总之，NF-κB诱导的miR-146a-5p上调通过靶向TIGAR促进了AD-HNNs中的氧化应激和焦亡。
