Institute of Neuroscience and the Collaborative Innovation Center for Brain Science, Chongqing Medical University, Chongqing 400016, China; Chongqing Key Laboratory of Neurobiology, Chongqing 400016, China.
Institute of Neuroscience and the Collaborative Innovation Center for Brain Science, Chongqing Medical University, Chongqing 400016, China; Chongqing Key Laboratory of Neurobiology, Chongqing 400016, China; Department of Neurology, Chongqing General Hospital, Chongqing 400014, China.
Neuroscience. 2018 Apr 15;376:24-39. doi: 10.1016/j.neuroscience.2018.02.010. Epub 2018 Feb 13.
The amygdala plays a key role in the pathophysiology of depression, but the molecular mechanisms underlying amygdalar hyperactivity in depression remain unclear. In this study, we used a chronic mild stress (CMS) protocol to separate susceptible and insusceptible rat subgroups. Proteomes in the amygdalae were analyzed differentially across subgroups based on labeling with isobaric tags for relative and absolute quantitation (iTRAQ) combined with mass spectrometry. Of 2562 quantified proteins, 102 were differentially expressed. Several proteins that might be associated with the stress insusceptibility/susceptibility difference, including synapse-related proteins, were identified in the amygdala. Immunoblot analysis identified changes in VGluT1, NMDA GluN2A and GluN2B and AMPA GluA1 receptors, and PSD-95, suggesting that CMS perturbs glutamatergic transmission in the amygdala. Changes in these regulatory and structural proteins provide insight into the molecular mechanisms underlying the abnormal synaptic morphological and functional plasticity in the amygdalae of stress-susceptible rats. Interestingly, the expression level of CaMKIIβ, potentially involved in regulation of glutamatergic transmission, was significantly increased in the susceptible group. Subsequent in vitro experimentation showed that overexpression of CaMKIIβ increased the expression of PSD-95 and GluA1 in cultured hippocampal neurons. This result suggested that CaMKIIβ functions upstream from PSD-95 and GluA1 to affect LTP-based postsynaptic functional plasticity in the amygdalae of susceptible rats. Therefore, amygdalar CaMKIIβ is a potential antidepressant target. Collectively, our findings contribute to a better understanding of amygdalar synaptic plasticity in depression.
杏仁核在抑郁症的病理生理学中起着关键作用，但抑郁症中杏仁核活性增加的分子机制仍不清楚。在这项研究中，我们使用慢性轻度应激（CMS）方案将易感性和不易感性大鼠亚组分开。根据相对和绝对定量标记（iTRAQ）与质谱联用，对杏仁核中的蛋白质组进行了差异分析。在 2562 个定量蛋白中，有 102 个表达差异。鉴定出几种可能与应激易感性/易感性差异相关的蛋白质，包括突触相关蛋白，存在于杏仁核中。免疫印迹分析鉴定出 VGluT1、NMDA GluN2A 和 GluN2B 以及 AMPA GluA1 受体和 PSD-95 的变化，表明 CMS 扰乱了杏仁核中的谷氨酸能传递。这些调节和结构蛋白的变化为应激易感性大鼠杏仁核异常突触形态和功能可塑性的分子机制提供了深入了解。有趣的是，CaMKIIβ的表达水平显著增加，CaMKIIβ可能参与调节谷氨酸能传递。随后的体外实验表明，CaMKIIβ的过表达增加了培养海马神经元中 PSD-95 和 GluA1 的表达。这一结果表明，CaMKIIβ在 PSD-95 和 GluA1 的上游发挥作用，影响易感性大鼠杏仁核中基于 LTP 的突触后功能可塑性。因此，杏仁核 CaMKIIβ是一种潜在的抗抑郁药靶标。总之，我们的研究结果有助于更好地理解抑郁症中杏仁核的突触可塑性。
