Ballion Bérengère, Bonnet Marie-Laure, Brot Sébastien, Gaillard Afsaneh
Laboratoire des neurosciences expérimentales et cliniques (LNEC), Université de Poitiers- INSERM 1084, Poitiers Cedex 9, 86073, France.
Centre hospitalier universitaire (CHU) de Poitiers, Poitiers, 86021, France.
Stem Cell Res Ther. 2025 May 9;16(1):232. doi: 10.1186/s13287-025-04344-z.
Parkinson's disease (PD) is a complex neurological disorder characterized by the progressive degeneration of midbrain dopaminergic (mDA) neurons in the substantia nigra (SN). This degeneration disrupts the basal ganglia loops, leading to both motor and non-motor dysfunctions. Cell therapy for PD aims to replace lost mDA neurons to restore the DA neurotransmission in the denervated forebrain targets. In clinical trials for PD, mDA neurons are implanted into the target area, the striatum, and not in the SN where they are normally located. This ectopic localisation of cells may affect the functionality of transplanted neurons due to the absence of appropriate host afferent regulation. We recently demonstrated that human induced pluripotent stem cells (hiPSCs) derived mDA progenitors grafted into the substantia nigra pars compacta (SNpc) in a mouse model of PD, differentiated into mature mDA neurons, restored the degenerated nigrostriatal pathway, and induced motor recovery. The objective of the present study was to evaluate the long-term functionality of these intranigral-grafted mDA neurons by assessing their electrophysiological properties.
We performed intranigral transplantation of hiPSC-derived mDA progenitors in a 6-hydroxydopamine RAG2-KO mouse model of PD. We recorded in vivo unit extracellular activity of grafted mDA neurons in anesthetised mice from 9 to 12 months post-transplantation. Their electrophysiological properties, including firing rates, patterns and spike characteristics, were analysed and compared with those of native nigral dopaminergic neurons from control mice.
We demonstrated that these grafted mDA neurons exhibited functional characteristics similar to those of native nigral dopaminergic neurons, such as large bi- or triphasic spike waveforms, low firing rates, pacemaker-like properties, and two single-spike firing patterns. Although grafted mDA neurons also displayed low discharge frequencies below 10 Hz, their mean frequency was significantly lower than that of nigral mDA neurons, with a differential pattern distribution.
Our findings indicate that grafted mDA neurons exhibit dopaminergic-like functional properties, including intrinsic membrane potential oscillations leading to regular firing patterns. Additionally, they demonstrated irregular and burst firing patterns, suggesting they receive modulatory inputs. However, grafted mDA neurons displayed distinct properties, potentially related to their human origin or the incomplete maturation one year after transplantation.
帕金森病（PD）是一种复杂的神经障碍，其特征是黑质（SN）中脑多巴胺能（mDA）神经元进行性退化。这种退化破坏了基底神经节环路，导致运动和非运动功能障碍。PD的细胞疗法旨在替代丢失的mDA神经元，以恢复去神经支配的前脑靶点中的多巴胺能神经传递。在PD的临床试验中，mDA神经元被植入目标区域纹状体，而非其正常所在的SN。由于缺乏适当的宿主传入调节，细胞的这种异位定位可能会影响移植神经元的功能。我们最近证明，在PD小鼠模型中，将人诱导多能干细胞（hiPSC）衍生的mDA祖细胞移植到黑质致密部（SNpc），这些祖细胞可分化为成熟的mDA神经元，恢复退化的黑质纹状体通路，并诱导运动恢复。本研究的目的是通过评估其电生理特性来评价这些脑内移植的mDA神经元的长期功能。
我们在6-羟基多巴胺RAG2基因敲除的PD小鼠模型中进行了hiPSC衍生的mDA祖细胞的脑内移植。在移植后9至12个月，我们记录了麻醉小鼠中移植的mDA神经元的体内单位细胞外活动。分析了它们的电生理特性，包括放电频率、模式和动作电位特征，并与对照小鼠的天然黑质多巴胺能神经元的电生理特性进行了比较。
我们证明，这些移植的mDA神经元表现出与天然黑质多巴胺能神经元相似的功能特征，如大的双相或三相动作电位波形、低放电频率、类似起搏器的特性以及两种单峰放电模式。虽然移植的mDA神经元也表现出低于10Hz的低放电频率，但其平均频率显著低于黑质mDA神经元，且放电模式分布不同。
我们的研究结果表明，移植的mDA神经元表现出类似多巴胺能的功能特性，包括导致规则放电模式的内在膜电位振荡。此外，它们还表现出不规则和爆发式放电模式，表明它们接受了调制输入。然而，移植的mDA神经元表现出独特的特性，这可能与它们的人类来源或移植一年后未完全成熟有关。
