A Single Neuron Scale Molecular Phenotype Map of the Right Atrial Ganglionic Plexus in the Pig Heart
We developed a spatially-tracked single neuron transcriptomics map of an intrinsic cardiac ganglion - the right atrial ganglionic plexus (RAGP) that is a critical mediator of vagal control of the sinoatrial node (SAN) activity. We developed a 3D representation of RAGP with extensive mapping of neurons and used neuronal tracing to identify the spatial distribution of the subset of neurons that project to the SAN. RNAseq of laser capture microdissected neurons revealed a distinct composition of RAGP neurons compared to CNS neuronal subtypes. High-throughput qPCR of hundreds of laser capture microdissected single neurons led to a surprising finding that cholinergic and catecholaminergic neuronal markers Th and Chat were correlated, suggesting multipotential phenotypes that can drive neuroplasticity within RAGP. Interestingly, no single gene or module was an exclusive marker of RAGP neuronal connectivity to SAN. Neuropeptide-receptor coexpression analysis revealed a combinatorial paracrine neuromodulatory network within RAGP, informing follow-on studies on the vagal control of RAGP to regulate cardiac function in health and disease. Overall design: 142 regional neuronal samples from the Right Atrial Ganglionic Plexus (RAGP) of a female Yucatan minipig were collected through Laser Capture Microdissection (LCM) and subjected to single-cell scale RNAseq using the Smart-3SEQ protocol. After quality check we were left with 90 samples with detectable expression in approximately 15,000 genes.