Forebrain GABAergic cell-selective genetic manipulation in mice

在Juan Belforte等人开发的该转基因系中，NMDAR的遗传消除在出生后第7天开始，并且靶向50%的皮质和海马GABA能细胞，主要是小清蛋白阳性细胞。Veronika Zsiros通过全细胞膜片钳记录显示几乎所有靶细胞中均不存在NMDA受体通道电流，从而通过电生理学证实了该受体的功能性敲除。然后，我们进行了一系列广泛的行为测试，发现突变体表现出多种精神疾病样表型。在该小鼠模型中，出生后早期的抑制网络修饰揭示了精神激动、感觉运动缺陷、快感缺乏行为、焦虑样行为以及筑巢和交配缺陷。 此外，我们还研究了学习相关任务中的认知障碍，并发现了空间工作记忆和短期社会记忆的缺陷。值得注意的是，抗精神病药物利培酮改善了工作记忆缺陷。 我们还观察到一些突变表型的恶化后，社会隔离压力，这可能是一个模型的压力诱导沉淀的人类精神疾病。有趣的是，当使用不同的菌株在青春期后在相同的细胞群体中对NR1进行基因消融时，我们没有观察到如上所述的行为表型，这表明出生后早期的NR1消融对于精神疾病样行为的发展至关重要。这些发现有力地支持了出生后早期皮层GABA能中间神经元NMDAR活性丧失导致精神障碍样行为的观点。 为了确定皮层抑制网络的功能障碍是如何在细胞水平上表现出来的，我们现在正在对自由运动的动物进行电生理记录。 通过这种新的遗传系统的发展，我们已经能够针对广泛分布的神经网络，并证明该系统的扰动可能在神经精神疾病的发病中发挥因果作用。

In this transgenic line developed by Juan Belforte et al, genetic elimination of the NMDARs begins at postnatal day 7 and is targeted to 50% of cortical and hippocampal GABAergic cells, primarily parvalbumin positive ones. Veronika Zsiros showed an absence of NMDA receptor channel currents in virtually all of the targeted cells by whole-cell patch-clamp recordings thus confirming via electrophysiology the functional knockout of this receptor. We then conducted an extensive battery of behavioral tests and found that the mutants exhibited a variety of psychiatric disease-like phenotypes. Early postnatal modification of inhibitory networks in this mouse model revealed psychomotor agitation, sensorimotor deficits, anhedonic behavior, anxiety-like behavior, and deficits in nesting and mating. In addition, we addressed cognitive impairments in learning-related tasks and found deficits in spatial working memory and short-term social memory. Notably, the working memory deficit was ameliorated by the antipsychotic drug, risperidone. We also observed an exacerbation of some mutant phenotypes following social isolation stress which may serve as a model for stress-induced precipitation of human psychiatric disorders. Interestingly, when NR1 was genetically ablated in the same population of cells after adolescence using a different strain, we observed no such behavioral phenotypes as described above, suggesting that early postnatal NR1 ablation is critical for the development of psychiatric disease-like behavior. These findings strongly support the notion that loss of NMDAR activity in cortical GABAergic interneurons during the early postnatal period leads to psychiatric disorder-like behavior. To identify how dysfunction of cortical inhibitory networks is manifest at the cellular level, we are now conducting electrophysiological recordings from freely moving animals. Through the development of this novel genetic system, we have been able to target a widely distributed neural network and demonstrate that perturbations of this system may play a causal role in the onset of neuropsychiatric disorders.