The role of transcription factor SOX6 in midbrain dopamine neuron lineage and molecular diversity

位于黑质腹侧部（SNc）的多巴胺（DA）神经元参与运动神经元的运动调节。 他们的退化与帕金森病（PD）等疾病有关，帕金森病是第二大疾病。 在美国常见的神经退行性疾病，几乎无法治愈。最近的研究表明， 神经元在分子上、解剖学上和功能上是异质的。事实上，某些DA神经元亚型 在PD动物模型中选择性地脆弱。因此，认识到这种多样性将对 帕金森病的病理生理学研究和治疗方法的发展。该提案旨在尽早阐明 分子事件，特别是涉及转录因子SOX 6，支配DA神经元的命运和多样化。 所有中脑DA能神经元都起源于胚胎中脑底板的祖细胞。Sox6是 在底板最内侧区域的祖细胞中表达。广泛认为Sox6-表达 祖细胞产生整个SNc DA神经元群体，然而，现有的出版物挑战了这一模型 这表明位于底板外侧区的Sox 6-祖细胞也有助于成体的生长。 SNC.然而，这些研究都没有进行Sox 6的谱系分析。一个合适的Sox 6祖细胞命运图将 然而，为了调和这些结果，现有的谱系追踪工具不足以解决这种祖先-后代关系， 因为Sox 6在祖细胞和有丝分裂后的神经元中表达。我们已经开发出一种新 谱系追踪工具，一种祖先限制的交叉命运映射策略（PRISM），它绕过了 基于重组酶的策略通过将标记锚定到祖细胞的局限性。通过PRISM，我们将 明确揭示了Sox6+祖细胞对特定DA神经元亚型的贡献，特别是那些 在PD模型中发现选择性脆弱。此外，我们将联合收割机PRISM与单细胞分辨率相结合 首次分析，以进一步完善Sox 6后代的分子景观。 我们的实验室强调Sox6表达是成年DA神经元分类的独特变量。不过， 需要更多的证据来确定SOX 6是否调节定义特定神经元亚型的基因。 探索Sox 6在发育中的作用将有助于理解祖细胞库是否仅限于产生 SNc的某些亚型。此外，阐明SOX 6的分子靶点将加深我们的研究。 了解DA神经元命运的决定。为此，我们将Sox 6敲除模型与RNA配对， 测序以确定该基因在DA神经元多样化中的必要性。我们还将应用ChIP- Seq以找到该转录因子的主要靶DNA序列。 提出的目标将提供深入了解Sox 6在DA神经元发育中的作用， 多样化，希望有助于优化再生医学的体外方案， 疾病建模

Dopamine (DA) neurons located in the Substantia nigra pars compacta (SNc) are involved in motor control, and their degeneration is associated with disorders such as Parkinson’s disease (PD), the second most frequent neurodegenerative disease in the US and practically incurable. Recent studies have revealed that DA neurons are molecularly, anatomically, and functionally heterogeneous. In fact, certain DA neuron subtypes are selectively vulnerable in animal PD models. Hence, recognizing this diversity will have a significant impact on the study of PD pathophysiology and the development of treatments. This proposal aims to shed light on early molecular events, particularly involving transcription factor SOX6, that govern DA neuron fate and diversification. All midbrain DA neurons originate from progenitors in the embryonic mesencephalic floor plate. Sox6 is expressed in progenitors of the most medial domain of the floor plate. It is widely accepted that Sox6-expressing progenitors give rise to the entire SNc DA neuron population, however, existing publications challenge this model suggesting that Sox6- progenitors, located in the lateral domain of the floor plate, also contribute to the adult SNc. Yet, none of these studies performed lineage analysis of Sox6. A proper Sox6 progenitor fate map would reconcile these results, however, existing lineage tracing tools are inadequate to resolve this progenitor-progeny relationship since Sox6 is expressed in progenitors and in postmitotic neurons. We have developed a new lineage tracing tool, a progenitor-restricted intersectional fate-mapping strategy (PRISM), that circumvents the limitations of recombinase-based strategies by anchoring the labeling to progenitors. With PRISM, we will unambiguously reveal the contribution of Sox6+ progenitors to specific DA neuron subtypes, particularly those found selectively vulnerable in PD models. Additionally, we will combine PRISM with a single-cell resolution analysis for the first time, to further refine the molecular landscape of the Sox6 progeny. Our lab has highlighted Sox6 expression as the distinctive variable in adult DA neuron classification. Still, more evidence is needed to establish whether SOX6 regulates genes that define specific neuronal subtypes. Exploring the role of Sox6 in development will help understand if progenitor pools are restricted to give rise to certain subtypes of the SNc. Additionally, elucidating the molecular targets of SOX6 will deepen our understanding of the determination of DA neuron fate. To this end, we will pair a Sox6 knockout model with RNA sequencing to determine the necessity of this gene in the diversification of DA neurons. We will also apply ChIP- Seq to find the main target DNA sequences of this transcription factor. The proposed aims will provide insights into the role of Sox6 in DA neuron development and diversification, with the hope of contributing to the optimization of in vitro protocols for regenerative medicine and disease modeling.