Stellate Transcriptomics Reveal Consistent Patterns of Gene Expression Across Species
Authors: Bardsley Emma N. , Davis Harvey , Bayles Richard , Habecker Beth Ann , Paterson David J. 
Published: June 2021

IntroductionSympathetic hyperactivity is a key feature of human hypertension as well as animal models of hypertension and cardiovascular disease. Sympathetic hyperactivity can result from cell‐autonomous changes in neurons that innervate cardiovascular target tissues. Stellate ganglia are of particular interest because the majority of sympathetic neurons innervating the heart reside there. Transcriptomics provides a powerful tool for identifying genomic changes that contribute to sympathetic dysfunction in disease.AimTo compare the transcriptomes of healthy stellate ganglia from adult rat and mouse.MethodRNA‐sequencing was carried out on individual stellate ganglia from 16‐week male Wistar rats or 18‐week male C57Bl6J mice. Mouse samples were depleted of ribosomal RNA prior to library preparation, while the rat library was prepared used OligoDT to enrich for mRNAs. Sequencing was carried out in an Illumina HiSeq 4000 at the High‐Throughput Genomics Group at the Wellcome Trust Centre for Human Genetics (Oxford) or the Massively Parallel Sequencing Shared Resource (OHSU). The rat transcriptome was aligned to the reference genome and transcripts were quantified using the Salmon‐DESeq2 method, which relies on exon matching. The mouse transcriptome was aligned to the reference genome by the OHSU Bioinformatics & Computational Biology Core using STAR, which includes non‐coding RNAs.ResultsA comparison of these independent analyses of gene expression reveals a significant degree of consistency regarding the most highly expressed genes, despite differences in the data processing pipeline. Genes closely associated with sympathetic neuron function were among the most highly expressed genes in both rat and mouse. We identified high levels of genes encoding proteins required for norepinephrine synthesis tyrosine hydroxylase (Th), L‐DOPA decarboxylase (Ddc), and dopamine beta hydroxylase (dbh), as well as genes encoding transporters for vesicular packaging (slc18a2, vesicular monoamine transporter 2) and removal of extracellular catecholamines (slc6a2, norepinephrine transporter, NET). High levels of mRNA encoding the sympathetic co‐transmitter Neuropeptide Y (Npy) were also observed.Genes encoding the Nerve Growth Factor receptors Ngfr (p75 neurotrophin receptor) and Trk1 (TrkA tyrosine kinase receptor) were abundantly expressed in rat and mouse stellate ganglia. Genes encoding structural proteins such as actins and tubulins were abundant in both species, as were genes encoding proteins involved in synaptic transmission including Snap25 (synaptosomal‐associated protein 25), Syt1 (synaptotagmin 1), and several nicotinic acetylcholine receptor subunits. The details of transcript counts differed between the two methods but the overall pattern of gene expression between species was quite consistent.ConclusionThese data will provide a normal baseline for identification of changes that occur in diseases associated with sympathetic over‐activity such as hypertension and cardiovascular disease.Support or Funding InformationNIH OT2TR001984, OHSU School of Medicine Dean's Fund, The Wellcome TrustThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.