Molecular identity, cellular physiology, and in vivo functions of nucleus accumbens astrocytes

项目摘要/摘要 星形胶质细胞广泛分布于整个中枢神经系统，是最丰富的非神经细胞类型。他们 是神经回路的重要组成部分，越来越多的证据表明，它们专门用于 特定的大脑区域。例如，蛋白质组学、转录学和电生理学实验表明 海马区和纹状体星形胶质细胞明显不同。然而，星形胶质细胞在体内是否具有异质性还不得而知。 脑区，如纹状体，神经元亚型基本一致。因此，背外侧纹状体 伏核(DLS)和伏核(NAC)接受不同的传入、延伸不同的传出和编码 不同的行为，但对纹状体区域内星形胶质细胞的异质性还没有基本的了解。我的 实验数据表明，与DLS星形胶质细胞相比，NAC星形胶质细胞具有不同的形态，并且单个- 细胞测序分子鉴定纹状体内5种星形胶质细胞亚型。在目标1中，我将扩展这些发现 并使用空间转录和RNAScope来确定每个纹状体星形胶质细胞亚型的位置。这 不偏不倚的方法将确定星形胶质细胞亚型是否定位于纹状体的亚区。腹侧纹状体 星形胶质细胞在功能上也不同于背侧纹状体星形胶质细胞，因为NAC星形胶质细胞具有显著的 细胞内钙离子对多巴胺的反应比背侧星形胶质细胞更强。NAC中的多巴胺(DA) 对于奖励学习至关重要，比如巴甫洛夫条件反射。因此，在目标2中，我将确定不同的 NAC钙反应在功能上与DA编码的巴甫洛夫刺激-奖赏学习有关。总而言之，这 该项目提议对纹状体星形胶质细胞异质性进行全面调查(目标1-优先领域1)， 这对于形成NAC星形胶质细胞钙信号的机制假说和确定因果关系是必不可少的 在DA编码的奖励学习中(目标2-优先领域4)。

Project Summary / Abstract Astrocytes are pervasive throughout the CNS and are the most abundant non-neuronal cell type. They are an essential component of neural circuits, and increasing evidence demonstrates they are specialized for specific brain regions. For example, proteomic, transcriptomic, and electrophysiology experiments show that hippocampal and striatal astrocytes are distinct. However, it is unknown if astrocytes are heterogeneous within brain regions such as the striatum where neuronal subtypes are largely uniform. Thus, the dorsal lateral striatum (DLS) and the nucleus accumbens (NAc) receive different afferents, extend different efferents, and encode different behaviors, and yet there is no basic understanding of astrocyte heterogeneity within striatal areas. My pilot data demonstrate that NAc astrocytes have different morphologies compared to DLS astrocytes, and single- cell sequencing molecularly identified 5 astrocyte subtypes in the striatum. In Aim 1, I will extend these findings and use spatial transcriptomics and RNAscope to identify the location of each striatal astrocyte subtype. This unbiased approach will determine if astrocyte subtypes are localized to subregions of the striatum. Ventral striatal astrocytes are also functionally distinct from dorsal striatal astrocytes, as NAc astrocytes have a significantly stronger intracellular Ca2+ signaling response to dopamine than do dorsal astrocytes. Dopamine (DA) in the NAc is critical for reward-learning such as Pavlovian conditioning. In Aim 2, I will therefore determine if the distinct NAc Ca2+ responses are functionally relevant to DA-encoded Pavlovian stimulus-reward learning. Together, this project proposes a comprehensive investigation of striatal astrocyte heterogeneity (Aim 1 – Priority Area #1), which is essential for forming mechanistic hypotheses and determining causality of NAc astrocyte Ca2+ signaling in DA-encoded reward learning (Aim 2 – Priority Area #4).