Gaertner Zachary, Oram Cameron, Schneeweis Amanda, Schonfeld Elan, Bolduc Cyril, Chen Chuyu, Dombeck Daniel, Parisiadou Loukia, Poulin Jean-Francois, Awatramani Rajeshwar
Northwestern University Feinberg School of Medicine, Dept of Neurology, Chicago, IL 60611.
Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
bioRxiv. 2024 Dec 22:2024.06.06.597807. doi: 10.1101/2024.06.06.597807.
Several studies have revealed that midbrain dopamine (DA) neurons, even within a single neuroanatomical area, display heterogeneous properties. In parallel, studies using single cell profiling techniques have begun to cluster DA neurons into subtypes based on their molecular signatures. Recent work has shown that molecularly defined DA subtypes within the substantia nigra (SNc) display distinctive anatomic and functional properties, and differential vulnerability in Parkinson's disease (PD). Based on these provocative results, a granular understanding of these putative subtypes and their alterations in PD models, is imperative. We developed an optimized pipeline for single-nuclear RNA sequencing (snRNA-seq) and generated a high-resolution hierarchically organized map revealing 20 molecularly distinct DA neuron subtypes belonging to three main families. We integrated this data with spatial MERFISH technology to map, with high definition, the location of these subtypes in the mouse midbrain, revealing heterogeneity even within neuroanatomical sub-structures. Finally, we demonstrate that in the preclinical LRRK2 knock-in mouse model of PD, subtype organization and proportions are preserved. Transcriptional alterations occur in many subtypes including those localized to the ventral tier SNc, where differential expression is observed in synaptic pathways, which might account for previously described DA release deficits in this model. Our work provides an advancement of current taxonomic schemes of the mouse midbrain DA neuron subtypes, a high-resolution view of their spatial locations, and their alterations in a prodromal mouse model of PD.
多项研究表明，中脑多巴胺（DA）神经元，即使在单个神经解剖区域内，也表现出异质性。与此同时，使用单细胞分析技术的研究已开始根据分子特征将DA神经元聚类为不同亚型。最近的研究表明，黑质（SNc）中分子定义的DA亚型具有独特的解剖和功能特性，以及在帕金森病（PD）中的不同易损性。基于这些引人注目的结果，对这些假定的亚型及其在PD模型中的改变进行细致入微的了解势在必行。我们开发了一种用于单核RNA测序（snRNA-seq）的优化流程，并生成了一个高分辨率的层次组织结构图，揭示了属于三个主要家族的20种分子上不同的DA神经元亚型。我们将这些数据与空间MERFISH技术相结合，以高清晰度绘制这些亚型在小鼠中脑的位置，揭示了即使在神经解剖亚结构内也存在异质性。最后，我们证明在PD的临床前LRRK2基因敲入小鼠模型中，亚型组织和比例得以保留。转录改变发生在许多亚型中，包括位于腹侧层SNc的那些亚型，在这些亚型中观察到突触途径中的差异表达，这可能解释了该模型中先前描述的DA释放缺陷。我们的工作推动了小鼠中脑DA神经元亚型当前分类方案的发展，提供了它们空间位置的高分辨率视图，以及它们在PD前驱小鼠模型中的改变情况。
