title: Serotonergic neuron regulation informed by in vivo single-cell transcriptomics.
abstract: Despite the recognized importance of the dorsal raphe (DR) serotonergic (5-HT) nuclei in the pathophysiology of depression and anxiety, the molecular components/putative drug targets expressed by these neurons are poorly characterized. Utilizing the promoter of an ETS domain transcription factor that is a stable marker of 5-HT neurons (Pet-1) to drive 5-HT neuronal expression of YFP, we identified 5-HT neurons in live acute slices. We isolated RNA from single 5-HT neurons in the ventromedial and lateral wings of the DR and performed single-cell RNA-Seq analysis identifying >500 G-protein coupled receptors (GPCRs) including receptors for classical transmitters, lipid signals, and peptides as well as dozens of orphan-GPCRs. Using these data to inform our selection of receptors to assess, we found that oxytocin and lysophosphatidic acid 1 receptors are translated and active in costimulating, with the α1-adrenergic receptor, the firing of DR 5-HT neurons, while the effects of histamine are inhibitory and exerted at H3 histamine receptors. The inhibitory histamine response provides evidence for tonic in vivo histamine inhibition of 5-HT neurons. This study illustrates that unbiased single-cell transcriptomics coupled with functional analyses provides novel insights into how neurons and neuronal systems are regulated.
authors.affiliation: 2University of Pennsylvania, 37 John Morgan Bldg., 3620 Hamilton Walk, Philadelphia, PA 19104, USA. eberwine@upenn.edu.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Spaethling
authors.forename: David
authors.initials: D
authors.lastname: Piel
authors.forename: Hannah
authors.initials: H
authors.lastname: Dueck
authors.forename: Peter T
authors.initials: PT
authors.lastname: Buckley
authors.forename: Jacqueline F
authors.initials: JF
authors.lastname: Morris
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Fisher
authors.forename: Jaehee
authors.initials: J
authors.lastname: Lee
authors.forename: Jai-Yoon
authors.initials: JY
authors.lastname: Sul
authors.forename: Junhyong
authors.initials: J
authors.lastname: Kim
authors.forename: Tamas
authors.initials: T
authors.lastname: Bartfai
authors.forename: Sheryl G
authors.initials: SG
authors.lastname: Beck
authors.forename: James H
authors.initials: JH
authors.lastname: Eberwine
mesh_terms: D000818:Animals; D004594:Electrophysiology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D059326:Serotonergic Neurons / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism
chemical_list: D043562:Receptors, G-Protein-Coupled; D012701:Serotonin
keywords: GPCR; RNA-Seq; dorsal raphe; electophysiology; histamine