Cell-Type Profiling of the Sympathetic Nervous System Using Spatial Transcriptomics and Spatial Mapping of mRNA [Spatial Transcriptomics]
Background: The molecular identification of neural progenitor cell populations that connect to establish the sympathetic nervous system (SNS) remains unclear. This is  due to technical limitations in the acquisition and spatial mapping of molecular information to tissue architecture.  Results: To address this, we applied Slide-seq spatial transcriptomics to intact fresh frozen chick trunk tissue transversely cryo-sectioned at the developmental stage prior to  SNS formation. In parallel, we performed age- and location-matched single cell (sc) RNA-seq and 10x Genomics Visium to inform our analysis. Downstream bioinformatic  analyses led to the unique molecular identification of neural progenitor cells within the peripheral sympathetic ganglia (SG) and spinal cord preganglionic neurons (PGNs). We  then successfully applied the HiPlex RNAscope fluorescence in situ hybridization and multispectral confocal microscopy to visualize 12 gene targets in stage-, age- and  location-matched chick trunk tissue sections.  Conclusions: Together, these data demonstrate a robust strategy to acquire and integrate single cell and spatial transcriptomic information, resulting in improved  resolution of molecular heterogeneities in complex neural tissue architectures. Successful application of this strategy to the developing SNS provides a roadmap for  functional studies of neural connectivity and platform to address complex questions in neural development and regeneration. Overall design: Visium spatial transcriptomics to intact fresh frozen chick trunk tissue transversely cryo-sectioned at the developmental stage prior to SNS formation