Department of Pediatrics, Shanxi Medical University, Taiyuan, China.
Neonatal Internal Medicine, Shanxi Children's Hospital, Taiyuan, China.
Yonsei Med J. 2020 Aug;61(8):660-669. doi: 10.3349/ymj.2020.61.8.660.
Neonatal hypoxic ischemic encephalopathy (HIE) is an essential factor underlying neonatal death and disability. This study sought to explore the role of miR-146b-5p in regulating neonatal HIE.
In vitro and in vivo HIE models were established in PC12 cells and 10-day neonatal Sprague Dawley rats, respectively. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to assess miR-146b-5p expression and inflammatory factors [interleukin (IL)-6 and tumor necrosis factor (TNF)-α] in brain lesions and PC12 cells, while enzyme-linked immunosorbent assay was employed to detect the expression of oxidative stress factors (SOD and GSH-Px). Gain- and loss-assays of miR-146b-5p were conducted to verify its role in modulating the viability and apoptosis of PC12 cells under oxygen-glucose deprivation (OGD) treatment. Expression of TLR4, IRAK1, TRAF6, TAK1, and NF-κB were examined by qRT-PCR and/or Western blot. Dual luciferase activity assay was conducted to identify relationships between miR-146b-5p and IRAK1.
In the HIE models, significant oxidative stress and inflammatory responses emerged upon upregulation of TLR4/IRAK1/TRAF6/TAK1/NF-κB signaling. Overexpression of miR-146b-5p greatly inhibited OGD-induced PC12 cell injury, inflammatory responses, and oxidative stress. Inhibiting miR-146b-5p, however, had the opposite effects. IRAK1 was found to be a target of miR-146b-5p, and miR-146b-5p overexpression suppressed the activation of IRAK1/TRAF6/TAK1/NF-κB signaling.
This study demonstrated that miR-146b-5p overexpression alleviates HIE-induced neuron injury by inhibiting the IRAK1/TRAF6/TAK1/NF-κB pathway.
新生儿缺氧缺血性脑病（HIE）是新生儿死亡和残疾的重要因素。本研究旨在探讨 miR-146b-5p 在调节新生儿 HIE 中的作用。
分别在 PC12 细胞和 10 日龄新生 Sprague Dawley 大鼠中建立体外和体内 HIE 模型。采用定量逆转录聚合酶链反应（qRT-PCR）检测脑损伤和 PC12 细胞中 miR-146b-5p 表达和炎症因子（白细胞介素（IL）-6 和肿瘤坏死因子（TNF）-α），酶联免疫吸附试验检测氧化应激因子（SOD 和 GSH-Px）表达。进行 miR-146b-5p 的增益和缺失实验，以验证其在调节氧葡萄糖剥夺（OGD）处理下 PC12 细胞活力和凋亡中的作用。采用 qRT-PCR 和/或 Western blot 检测 TLR4、IRAK1、TRAF6、TAK1 和 NF-κB 的表达。进行双荧光素酶活性测定以鉴定 miR-146b-5p 与 IRAK1 之间的关系。
在 HIE 模型中，TLR4/IRAK1/TRAF6/TAK1/NF-κB 信号通路的上调导致明显的氧化应激和炎症反应。miR-146b-5p 的过表达极大地抑制了 OGD 诱导的 PC12 细胞损伤、炎症反应和氧化应激。然而，抑制 miR-146b-5p 则产生相反的效果。IRAK1 被鉴定为 miR-146b-5p 的靶标，miR-146b-5p 的过表达抑制了 IRAK1/TRAF6/TAK1/NF-κB 信号通路的激活。
本研究表明，miR-146b-5p 的过表达通过抑制 IRAK1/TRAF6/TAK1/NF-κB 通路减轻 HIE 诱导的神经元损伤。
