Department of Geriatrics, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong 264100, China.
Department of Pharmacy, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong 264100, China.
Life Sci. 2020 Jul 1;252:117637. doi: 10.1016/j.lfs.2020.117637. Epub 2020 Apr 3.
Berberine plays a neuroprotective role in neurodegenerative diseases, including Alzheimer's disease (AD). Circular RNAs (circRNAs) function as crucial players in AD pathogenesis. In the current work, we aimed to investigate whether circRNA histone deacetylase 9 (circHDAC9) was involved in the regulation of berberine in AD.
Cell viability and apoptosis were determined by the Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. Enzyme-linked immunosorbent assay (ELISA) was used to assess caspase-3 activity and the production of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α). The levels of circHDAC9 and miR-142-5p were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Subcellular fractionation assays were performed to evaluate the localization of circHDAC9. The direct interaction between circHDAC9 and miR-142-5p was confirmed by dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays.
Our data indicated that circHDAC9 was indeed a circular transcript and mainly localized in the cytoplasm. 42-residue β-amyloid (Aβ42) triggered a significant down-regulation in circHDAC9 and a striking up-regulation in miR-142-5p in human neuronal (HN) cells. Berberine relieved Aβ42-induced HN cell neurotoxicity. Moreover, berberine resulted in increased circHDAC9 expression and decreased miR-142-5p level in Aβ42-treated HN cells. Berberine alleviated Aβ42-induced neuronal damage in HN cells by up-regulating circHDAC9. Furthermore, circHDAC9 acted as a molecular sponge of miR-142-5p. CircHDAC9 overexpression alleviated Aβ42-induced HN cell neurotoxicity via miR-142-5p.
Our current study suggested that berberine protected HN cell from Aβ42-induced neuronal damage at least partly through regulating the circHDAC9/miR-142-5p axis, highlighting novel evidence for the neuroprotective effect of berberine in AD.
小檗碱在神经退行性疾病中发挥神经保护作用，包括阿尔茨海默病（AD）。环状 RNA（circRNA）作为 AD 发病机制中的关键因子发挥作用。在本研究中，我们旨在研究环状 RNA 组蛋白去乙酰化酶 9（circHDAC9）是否参与调节 AD 中的小檗碱。
通过细胞计数试剂盒-8（CCK-8）检测和流式细胞术分别测定细胞活力和细胞凋亡。酶联免疫吸附试验（ELISA）用于测定 caspase-3 活性以及白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）和肿瘤坏死因子-α（TNF-α）的产生。通过实时定量聚合酶链反应（qRT-PCR）检测 circHDAC9 和 miR-142-5p 的水平。采用亚细胞分离测定法评估 circHDAC9 的定位。通过双荧光素酶报告、RNA 免疫沉淀（RIP）和 RNA 下拉测定证实 circHDAC9 与 miR-142-5p 之间的直接相互作用。
我们的数据表明，circHDAC9 确实是一种环状转录本，主要定位于细胞质中。42 个残基β-淀粉样蛋白（Aβ42）在人神经元（HN）细胞中引起 circHDAC9 的显著下调和 miR-142-5p 的显著上调。小檗碱缓解 Aβ42 诱导的 HN 细胞神经毒性。此外，小檗碱导致 Aβ42 处理的 HN 细胞中 circHDAC9 表达增加和 miR-142-5p 水平降低。小檗碱通过上调 circHDAC9 减轻 Aβ42 诱导的 HN 细胞神经元损伤。此外，circHDAC9 作为 miR-142-5p 的分子海绵发挥作用。circHDAC9 的过表达通过 miR-142-5p 减轻 Aβ42 诱导的 HN 细胞神经毒性。
本研究表明，小檗碱通过调节 circHDAC9/miR-142-5p 轴保护 HN 细胞免受 Aβ42 诱导的神经元损伤，为小檗碱在 AD 中的神经保护作用提供了新的证据。
