LncRNA miR-17-92a-1 cluster host gene (MIR17HG) promotes neuronal damage and microglial activation by targeting the microRNA-153-3p/alpha-synuclein axis in Parkinson’s disease

Long noncoding RNAs (lncRNAs) have been regarded as modulators of neurodegenerative diseases. Here, we addressed the role of lncRNA miR-17-92a-1 cluster host gene (MIR17HG) in Parkinson’s disease (PD). C57BL/6 mice and SH-SY5Y cells were intervened with 6-hydroxydopamine (6-OHDA) to set up PD models <i>in vivo</i> and <i>in vitro</i>. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was implemented to compare the expression of MIR17HG and miR-153-3p. Cell viability and apoptosis were estimated by 3-(4,5-dimethyithiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and Western blot (WB). The expression of alpha-synuclein (α-syn, SNCA) in BV2 was validated by enzyme-linked immunosorbent assay (ELISA). Reactive oxygen species (ROS) generation and lactate dehydrogenase (LDH) and superoxide dismutase (SOD) activity were evaluated using commercially available kits. Bioinformatics analysis, the dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and qRT-PCR were conducted to demonstrate the interactions between miR-153-3p, MIR17HG, and alpha-synuclein (SNCA). MIR17HG was up-regulated while miR-153-3p was down-regulated in PD patients, mouse models and cells. Inhibiting MIR17HG attenuated neuronal apoptosis, microglial activation and SNCA expression in PD mice. Conditioned medium from 6-OHDA-treated SH-SY5Y cells intensified microglial inflammation, while inhibition of MIR17HG or overexpression of miR-153-3p restrained the inflammatory responses. MIR17HG’s function was enforced by sponging miR-153-3p and releasing the attenuation of the putative targets of miR-153-3p and SNCA. Overall, MIR17HG, by targeting miR-153-3p and up-regulating SNCA, stimulates neuronal apoptosis and microglial inflammation in PD.

长链非编码RNA（long noncoding RNAs，lncRNAs）已被证实为神经退行性疾病的调控因子。本研究探讨了长链非编码RNA miR-17-92a-1簇宿主基因（MIR17HG）在帕金森病（Parkinson’s disease，PD）中的作用。我们使用6-羟基多巴胺（6-hydroxydopamine，6-OHDA）干预C57BL/6小鼠及SH-SY5Y细胞，分别构建体内（in vivo）与体外（in vitro）帕金森病模型。采用定量反转录聚合酶链反应（quantitative reverse transcription-polymerase chain reaction，qRT-PCR）检测MIR17HG与miR-153-3p的表达水平；通过3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐（3-(4,5-dimethyithiazol-2-yl)-2,5-diphenyl-tetrazolium bromide，MTT）法与蛋白质印迹（Western blot，WB）检测细胞活力与凋亡情况；采用酶联免疫吸附测定（enzyme-linked immunosorbent assay，ELISA）验证BV2细胞中α-突触核蛋白（alpha-synuclein，α-syn、SNCA）的表达水平；使用商品化试剂盒检测活性氧（reactive oxygen species，ROS）生成量及乳酸脱氢酶（lactate dehydrogenase，LDH）、超氧化物歧化酶（superoxide dismutase，SOD）活性。通过生物信息学分析、双荧光素酶报告基因实验、RNA免疫沉淀（RNA immunoprecipitation，RIP）及qRT-PCR，验证miR-153-3p、MIR17HG与α-突触核蛋白（SNCA）之间的相互作用。在帕金森病患者、小鼠模型及细胞模型中，MIR17HG表达上调，而miR-153-3p表达下调。抑制MIR17HG可减轻帕金森病小鼠的神经元凋亡、小胶质细胞活化及SNCA表达。6-OHDA处理的SH-SY5Y细胞条件培养基可加剧小胶质细胞炎症反应，而抑制MIR17HG或过表达miR-153-3p则可抑制该炎症应答。MIR17HG通过海绵吸附miR-153-3p，解除其对靶基因SNCA的抑制作用，从而发挥调控功能。综上，MIR17HG通过靶向miR-153-3p并上调SNCA的表达，促进帕金森病中的神经元凋亡与小胶质细胞炎症反应。