Multiple target of hAmylin on rat primary hippocampal neurons.
Multiple target of hAmylin on rat primary hippocampal neurons.
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hAmylin 对大鼠原代海马神经元的多重靶点。
DOI：
10.1016/j.neuropharm.2016.07.008
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发表时间：
2017
影响因子：
4.7
通讯作者：
Zhang Wei
中科院分区：
文献类型：
--
作者：
Zhang Nan;Yang Shengchang;Wang Chang;Zhang Jianghua;Huo Lifang;Cheng Yiru;Wang Chuan;Jia Zhanfeng（贾占峰）;Ren Leiming;Kang Lin;Zhang Wei
阿尔茨海默病（AD）和II型糖尿病（DM2）是最常见的衰老相关疾病，其特征分别为β-淀粉样蛋白和胰淀素积累。多项研究表明，这两种疾病之间存在很强的相关性。大脑中的胰淀素寡聚化似乎是发展AD的一个新的危险因素。尽管胰淀素聚集已被证明通过改变Ca2+稳态诱导神经元细胞毒性，但其潜在机制尚未得到充分探讨。在这项研究中，我们利用钙成像和全细胞膜片钳记录研究了胰淀素对大鼠海马神经元的影响。我们证明了amylin受体拮抗剂AC187可以消除低浓度人amylin （hAmylin）诱导的Ca2+反应。然而，高浓度hAmylin诱导的Ca2+反应是独立于amylin受体的。这种作用依赖于细胞外Ca2+。此外，阻断l型Ca2+通道部分降低了hamylin诱导的Ca2+反应。在全细胞记录中，hAmylin使膜电位去极化。此外，瞬态受体电位（TRP）通道拮抗剂钌红（RR）的应用减弱了hamylin诱导的Ca2+升高。单细胞RT-PCR结果显示，瞬时受体电位香草蛋白4 (TRPV4) mRNA在大多数hamylin反应神经元中表达。此外，选择性敲低TRPV4通道可抑制hamylin诱发的Ca2+反应。这些结果表明，不同浓度的hAmylin通过不同的途径起作用。胰淀素受体介导低浓度胰淀素的兴奋作用。相反，当hAmylin浓度较高时，hAmylin聚集体在神经元膜上沉淀，激活TRPV4通道，随后触发膜电压门控钙通道开放，然后膜去极化。因此，我们的数据表明TRPV4是hAmylin对海马神经元细胞毒性作用的关键分子介质。
Alzheimer's disease (AD) and type II diabetes mellitus (DM2) are the most common aging-related diseases and are characterized by β-amyloid and amylin accumulation, respectively. Multiple studies have indicated a strong correlation between these two diseases. Amylin oligomerization in the brain appears to be a novel risk factor for developing AD. Although amylin aggregation has been demonstrated to induce cytotoxicity in neurons through altering Ca2+homeostasis, the underlying mechanisms have not been fully explored. In this study, we investigated the effects of amylin on rat hippocampal neurons using calcium imaging and whole-cell patch clamp recordings. We demonstrated that the amylin receptor antagonist AC187 abolished the Ca2+response induced by low concentrations of human amylin (hAmylin). However, the Ca2+response induced by higher concentrations of hAmylin was independent of the amylin receptor. This effect was dependent on extracellular Ca2+. Additionally, blockade of L-type Ca2+channels partially reduced hAmylin-induced Ca2+response. In whole-cell recordings, hAmylin depolarized the membrane potential. Moreover, application of the transient receptor potential (TRP) channel antagonist ruthenium red (RR) attenuated the hAmylin-induced increase in Ca2+. Single-cell RT-PCR demonstrated that transient receptor potential vanilloid 4 (TRPV4) mRNA was expressed in most of the hAmylin-responsive neurons. In addition, selective knockdown of TRPV4 channels inhibited the hAmylin-evoked Ca2+response. These results indicated that different concentrations of hAmylin act through different pathways. The amylin receptor mediates the excitatory effects of low concentrations of hAmylin. In contrast, for high concentrations of hAmylin, hAmylin aggregates precipitated on the neuronal membrane, activated TRPV4 channels and subsequently triggered membrane voltage-gated calcium channel opening followed by membrane depolarization. Therefore, our data suggest that TRPV4 is a key molecular mediator for the cytotoxic effects of hAmylin on hippocampal neurons.