Department of Neurology, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, PR China.
Department of Psychiatry, JiangXi Mental Hospital, Nanchang 330029, Jiangxi Province, PR China.
Neuroscience. 2021 Jan 1;452:1-12. doi: 10.1016/j.neuroscience.2020.10.005. Epub 2020 Oct 15.
It has been demonstrated Inhibitor Kappa B Kinase β (IKKβ) facilitates autophagy, which in turn mediates p-Tau protein clearance. However, the specific regulatory mechanism in Alzheimer's disease (AD) remains unclear. Firstly, AD model was generated by the intracerebroventricular (ICV) injection of the Β-amyloid 1-42 (Aβ) peptide. Subsequently, mice were injected with shRNA adenoviral transduction particles designed to target DJ-1 or Aβ or Aβ + shNC or Aβ + shRNA against DJ-1. shRNA against DJ-1 were injected into hippocampus of mice (8 × 10 viral particles for each mice) for seven consecutive days. Immunohistochemistry was performed to detect the accumulation of Aβ in the hippocampus of mice, and Hematoxylin-Eosin (HE) staining assay was carried to detect pathological changes in the hippocampus of mice. Further, sh-IKKβ, shDJ-1, pcDNA-IKKβ and pcDNA-DJ-1 plasmids were transfected into HT-22 cells, MTT assay, TUNEL staining and Hoechst staining were performed to detect cell viability and apoptosis, respectively. Western blotting was carried to measure the relative expression of proteins. Findings indicated that Aβ inhibited autophagy and up-regulated p-Tau protein expression; Overexpression of IKKβ and DJ-1 all rescued the autophagy inhibited by Aβ and down-regulated p-Tau protein expression induced by Aβ; DJ-1 up-regulated IKKβ via p-VHL, further promoted autophagy and reduced the expression of p-Tau protein; DJ-1 knockdown inhibited autophagy and up-regulated p-Tau protein expression, resulting in delayed behavior in mice. In conclusion, IKKβ, modulated by DJ-1/p-VHL, reduces p-Tau accumulation via autophagy in AD's disease model. This study may provide theoretical basis for the treatment of AD.
已证实，IKKβ（Inhibitor Kappa B Kinase β）可促进自噬，进而介导 p-Tau 蛋白清除。然而，阿尔茨海默病（AD）中具体的调控机制仍不清楚。首先，通过脑室内（ICV）注射 Β-淀粉样蛋白 1-42（Aβ）肽生成 AD 模型。随后，通过注射靶向 DJ-1 或 Aβ 或 Aβ+shNC 或 Aβ+shRNA 靶向 DJ-1 的 shRNA 腺病毒转导颗粒对小鼠进行处理。连续 7 天，向小鼠海马区注射 shRNA 针对 DJ-1（每只小鼠 8×10 个病毒颗粒）。采用免疫组织化学法检测小鼠海马区 Aβ 的蓄积情况，采用苏木精-伊红（HE）染色法检测小鼠海马区的病理变化。进一步，将 sh-IKKβ、shDJ-1、pcDNA-IKKβ 和 pcDNA-DJ-1 质粒转染至 HT-22 细胞，采用 MTT 检测、TUNEL 染色和 Hoechst 染色分别检测细胞活力和凋亡，Western blot 检测蛋白的相对表达量。结果表明，Aβ 抑制自噬并上调 p-Tau 蛋白表达；过表达 IKKβ 和 DJ-1 均可挽救 Aβ 抑制的自噬，并下调 Aβ 诱导的 p-Tau 蛋白表达；DJ-1 通过 p-VHL 上调 IKKβ，进一步促进自噬并减少 p-Tau 蛋白表达；DJ-1 敲低抑制自噬并上调 p-Tau 蛋白表达，导致小鼠行为迟缓。综上所述，IKKβ 通过 DJ-1/p-VHL 调控，在 AD 疾病模型中通过自噬减少 p-Tau 积累。本研究可能为 AD 的治疗提供理论依据。
