前额皮层LncRNA-GM2694/HSP70通路调控抑郁症的机理研究

Prefrontal cortex dysfunction is the leading cause of depression, some studies have found that mitochondrial dysfunction of the prefrontal cortex in patients with depression. It has also been found that impair of synaptic plasticity results depression. We previously used LncRNA microarrays to find that long non-coding RNA GM2694 was highly expressed in blood and mPFC of depressed mice, and accompanied by mitochondrial dysfunction and impair of synaptic plasticity. The mitophagy regulatory protein HSP70 was found to be a downstream target of GM2694 by RNA pull-down combined with protein profiling. Based on this, we speculate that stress increases the expression of GM2694, down-regulating HSP70 to inhibit mitophagy, causing mitochondrial dysfunction, and facilitating stress-induced impairs of synaptic plasticity. This project intends to elucidate the relationship between LncRNA GM2694 and the pathogenesis of depression through electron microscopy, mitophagy fluorescent labeling, molecular biology approaches and patch clamp, and investigate the role and mechanism of GM2694-HSP70 pathway in mitophagy and depression. Our research may provide new candidate molecules for biomarker of depression and development of antidepressants.

前额皮层功能异常与抑郁症发病密切相关，研究发现抑郁症患者前额皮层线粒体功能发生障碍，亦有研究发现神经元突触可塑性损伤介导抑郁症的发病。我们前期通过LncRNA芯片筛选发现抑郁敏感小鼠mPFC脑区和外周血GM2694表达增加，并伴随有线粒体功能障碍和突触可塑性损伤。通过RNA pull-down结合蛋白质谱分析，我们发现参与线粒体自噬调节的HSP70为GM2694的靶分子。据此，我们推测应激诱导GM2694表达增加，通过下调HSP70抑制线粒体自噬，引起线粒体功能障碍，易化应激对可塑性的损伤。本课题拟通过电镜、线粒体自噬荧光标记、分子生物学技术和脑片膜片钳，阐明LncRNA GM2694与抑郁症发病的关系，并探究GM2694-HSP70信号通路在线粒体自噬和抑郁症发病中的作用与机制，为抑郁症生物标记物的研究与抗抑郁药的研发提供新的候选分子。

目的：抑郁症是常见的精神情感障碍性疾病，目前全世界大约有5%的成年人患有抑郁症。临床影像学结果发现抑郁症患者的内侧前额叶皮层（mPFC）出现明显的结构异常。长链非编码RNA（lncRNA）在调节神经元突触结构与功能中发挥重要作用。本研究通过构建慢性社会挫败应激（CSDS）模型，研究长链非编码RNA在抑郁样行为中的作用和机制。.方法：建立CSDS模型；通过社会接触实验和糖水偏好实验检测小鼠的抑郁样行为；小鼠lncRNA芯片筛选出差异性表达lncRNA， qPCR检测RNA的表达变化，Western blotting检测蛋白表达变化，病毒载体调节lncRNA的表达；脑片膜片钳记录神经元电生理的变化。RNA pull-down实验和RNA免疫共沉淀寻找与lncRNA相互作用的调节蛋白。.结果：（1）CSDS模型小鼠mPFC脑区lncRNA-Gm2694的表达增加。（2）mPFC脑区沉默Gm2694缓解小鼠的抑郁行为，并改善慢性应激损伤的突触可塑性。（3） 脑区过表达Gm2694增加小鼠的应激易感性。（4）Gm2694和GRP78的底物结合结构域相互作用。（5）CSDS诱导Gm2694-GRP78复合物的形成破坏内质网应激的稳态平衡。（6） Gm2694-GRP78复合物的形成降低AMPA受体的膜表达。（7）mPFC脑区过表达GRP78缓解小鼠的抑郁行为，并改善慢性应激损伤的突触可塑性。.结论： CSDS增加mPFC脑区Gm2694的表达，Gm2694通过与GRP78相互作用，沉默GRP78的功能，扰乱内质网应激的稳态平衡，并导致AMPA受体的膜表达减少。mPFC脑区过表达GRP78通过促进AMPA受体的膜表达，改善小鼠的抑郁样行为。.