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

项目总结/摘要 星形胶质细胞遍布CNS，是最丰富的非神经元细胞类型。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、转录组学和电生理学实验表明， 海马和纹状体星形胶质细胞是不同的。然而，尚不清楚星形胶质细胞是否是异质的， 大脑区域，如纹状体，其中神经元亚型在很大程度上是一致的。因此，背侧纹状体 (DLS)延髓核（NAc）接受不同的传入，发出不同的传出，并编码 不同的行为，但还没有基本的了解星形胶质细胞的异质性内纹状体区。我 试验数据表明，NAc星形胶质细胞与DLS星形胶质细胞相比具有不同的形态，并且单个- 细胞测序分子鉴定了纹状体中的5种星形胶质细胞亚型。在目标1中，我将扩展这些发现 并使用空间转录组学和RNAscope来确定每个纹状体星形胶质细胞亚型的位置。这 无偏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。纹状体的 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 对多巴胺的胞内Ca 2+信号反应比背侧星形胶质细胞强。NAc中的多巴胺（DA） 对奖赏学习如巴甫洛夫条件反射至关重要。因此，在目标2中，我将确定 NAc Ca 2+反应与DA编码的巴甫洛夫刺激奖励学习功能相关。在一起，这 该项目提出了纹状体星形胶质细胞异质性的全面调查（目标1 -优先领域#1）， 这对于形成机制假说和确定NAc星形胶质细胞Ca 2+信号传导的因果关系是必不可少的 DA编码的奖励学习（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).