Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.
Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, United States.
Elife. 2022 Jul 26;11:e75398. doi: 10.7554/eLife.75398.
The mTOR pathway is an essential regulator of cell growth and metabolism. Midbrain dopamine neurons are particularly sensitive to mTOR signaling status as activation or inhibition of mTOR alters their morphology and physiology. mTOR exists in two distinct multiprotein complexes termed mTORC1 and mTORC2. How each of these complexes affect dopamine neuron properties, and whether they have similar or distinct functions is unknown. Here, we investigated this in mice with dopamine neuron-specific deletion of or , which encode obligatory components of mTORC1 or mTORC2, respectively. We find that inhibition of mTORC1 strongly and broadly impacts dopamine neuron structure and function causing somatodendritic and axonal hypotrophy, increased intrinsic excitability, decreased dopamine production, and impaired dopamine release. In contrast, inhibition of mTORC2 has more subtle effects, with selective alterations to the output of ventral tegmental area dopamine neurons. Disruption of both mTOR complexes leads to pronounced deficits in dopamine release demonstrating the importance of balanced mTORC1 and mTORC2 signaling for dopaminergic function.
mTOR 通路是细胞生长和代谢的重要调节剂。中脑多巴胺神经元对 mTOR 信号状态特别敏感,因为 mTOR 的激活或抑制会改变它们的形态和生理学。mTOR 存在于两种不同的多蛋白复合物中,分别称为 mTORC1 和 mTORC2。这些复合物中的每一种复合物如何影响多巴胺神经元的特性,以及它们是否具有相似或不同的功能尚不清楚。在这里,我们使用多巴胺神经元特异性缺失或 的小鼠进行了研究,这两种基因分别编码 mTORC1 或 mTORC2 的必需成分。我们发现,mTORC1 的抑制强烈而广泛地影响多巴胺神经元的结构和功能,导致树突和轴突的萎缩,增加了内在的兴奋性,减少了多巴胺的产生,并损害了多巴胺的释放。相比之下,mTORC2 的抑制作用更为微妙,选择性地改变了腹侧被盖区多巴胺神经元的输出。破坏两个 mTOR 复合物都会导致多巴胺释放明显减少,这表明平衡的 mTORC1 和 mTORC2 信号对多巴胺能功能的重要性。