Ni Anjie, Ernst Carl
Department of Human Genetics, McGill University, Montreal, QC, Canada.
Front Cell Neurosci. 2022 Mar 4;16:826193. doi: 10.3389/fncel.2022.826193. eCollection 2022.
There are 400-500 thousand dopaminergic cells within each side of the human substantia nigra pars compacta (SNpc) making them a minuscule portion of total brain mass. These tiny clusters of cells have an outsized impact on motor output and behavior as seen in disorders such as Parkinson's disease (PD). SNpc dopaminergic neurons are more vulnerable to oxidative stress compared to other brain cell types, but the reasons for this are not precisely known. Here we provide evidence to support the hypothesis that this selective vulnerability is because SNpc neurons sustain high metabolic rates compared to other neurons. A higher baseline requirement for ATP production may lead to a selective vulnerability to impairments in oxidative phosphorylation (OXPHOS) or genetic insults that impair Complex I of the electron transport chain. We suggest that the energy demands of the unique morphological and electrophysiological properties of SNpc neurons may be one reason these cells produce more ATP than other cells. We further provide evidence to support the hypothesis that transcription factors (TFs) required to drive induction, differentiation, and maintenance of midbrain dopaminergic neural progenitor cells which give rise to terminally differentiated SNpc neurons are uniquely involved in both developmental patterning and metabolism, a dual function unlike other TFs that program neurons in other brain regions. The use of these TFs during induction and differentiation may program ventral midbrain progenitor cells metabolically to higher ATP levels, allowing for the development of those specialized cell processes seen in terminally differentiated cells. This paper provides a cellular and developmental framework for understanding the selective vulnerability of SNpc dopaminergic cells to oxidative stress.
人类黑质致密部(SNpc)每一侧有40万至50万个多巴胺能细胞,它们在整个脑质量中只占极小的一部分。这些微小的细胞簇对运动输出和行为有着巨大影响,如在帕金森病(PD)等疾病中所见。与其他脑细胞类型相比,SNpc多巴胺能神经元更容易受到氧化应激的影响,但其原因尚不完全清楚。在此,我们提供证据支持以下假说:这种选择性易损性是因为与其他神经元相比,SNpc神经元维持着较高的代谢率。对ATP生成的更高基线需求可能导致对氧化磷酸化(OXPHOS)损伤或损害电子传递链复合体I的基因损伤具有选择性易损性。我们认为,SNpc神经元独特的形态和电生理特性所产生的能量需求可能是这些细胞比其他细胞产生更多ATP的原因之一。我们还进一步提供证据支持以下假说:驱动中脑多巴胺能神经祖细胞的诱导、分化和维持(这些祖细胞可产生终末分化的SNpc神经元)所需的转录因子(TFs)独特地参与了发育模式形成和代谢,这是一种与在其他脑区编程神经元的其他TFs不同的双重功能。在诱导和分化过程中使用这些TFs可能会使腹侧中脑祖细胞在代谢上被编程为更高的ATP水平,从而使终末分化细胞中所见的那些特殊细胞过程得以发育。本文为理解SNpc多巴胺能细胞对氧化应激的选择性易损性提供了一个细胞和发育框架。