Department of General medicine, Kobe Graduate School of Medicine, Kobe University, Kobe Center for the Comprehensive Care and Research on Memory Disorders, National Center for Geriatrics and Gerontology, Obu, Japan.
Geriatr Gerontol Int. 2011 Oct;11(4):517-24. doi: 10.1111/j.1447-0594.2011.00712.x. Epub 2011 May 18.
The molecular basis for impaired glucose metabolism in patients with Alzheimer's disease (AD) has not been fully clarified. We tested whether insulin and amyloid (A)β(1-42) oligomers would regulate glucose metabolism and energy homeostasis directly in cultured rat hippocampal neurons and evaluated possible interactions between insulin signaling and Aβ(1-42) oligomers.
Dissociated hippocampal neurons were prepared from Wistar rat embryos at day 21 of gestation and cultured for 14days. Cultured neurons were exposed to insulin (1µM) for 30min, and Aβ(1-42) oligomers (1µM) were added to culture media for 10-30min. The glucose uptake of cultured neurons was measured by enzymatic fluorescence assay using 2-deoxy-d-glucose (2DG), and adenosine triphosphate (ATP) contents were quantified using a luciferin/luciferase luminescence assay.
Aβ(1-42) oligomers did not suppress 2DG uptake, reflecting the activities of glucose transporters and/or hexokinase, but led to disrupted ATP contents in the presence and absence of monocarboxylates (lactate/pyruvate). Insulin and C-peptide did not change glucose uptake or ATP concentrations.
The primary target of Aβ(1-42) oligomers might be mitochondria, which could explain the reduced cerebral glucose levels in patients with AD. Moreover, insulin signaling was not directly linked to glucose metabolism or energy homeostasis in cultured rat hippocampal neurons.
阿尔茨海默病（AD）患者葡萄糖代谢受损的分子基础尚未完全阐明。我们检测了胰岛素和淀粉样蛋白（A）β（1-42）寡聚体是否会直接在培养的大鼠海马神经元中调节葡萄糖代谢和能量稳态，并评估了胰岛素信号与 Aβ（1-42）寡聚体之间可能存在的相互作用。
从 Wistar 大鼠胚胎第 21 天分离海马神经元并培养 14 天。培养的神经元用胰岛素（1μM）处理 30min，并用 Aβ（1-42）寡聚体（1μM）处理培养物 10-30min。用 2-脱氧-d-葡萄糖（2DG）的酶荧光测定法测量培养神经元的葡萄糖摄取量，并使用荧光素/荧光素酶发光测定法定量测定三磷酸腺苷（ATP）含量。
Aβ（1-42）寡聚体不抑制 2DG 摄取，反映了葡萄糖转运体和/或己糖激酶的活性，但在存在和不存在单羧酸（乳酸/丙酮酸）的情况下导致 ATP 含量紊乱。胰岛素和 C 肽不会改变葡萄糖摄取或 ATP 浓度。
Aβ（1-42）寡聚体的主要靶标可能是线粒体，这可以解释 AD 患者大脑葡萄糖水平降低的原因。此外，胰岛素信号与培养的大鼠海马神经元中的葡萄糖代谢或能量稳态没有直接联系。
