Project description:The goal of this study was to analyze global gene expression in specific populations of nociceptor sensory neurons, the neurons that detect damaging/noxious stimuli. The dorsal root ganglia (DRG), trigeminal ganglia, and nodose ganglia are anatomically distinct peripheral sensory ganglia that contain nociceptors which innervate skin, gut, lungs, and other distinct organ tissues. We used flow cytometry to purify nociceptors from these ganglia and profiled their global gene expression signatures to compare gene expression between these different anatomically distinct nociceptors. Nav1.8-Cre were bred with Rosa26-TdTomato to generate Nav1.8-Cre/R26-TdTomato reporter progeny, where all peripheral nociceptor neurons are genetically marked with red fluroescence due to specific expression of the TTX- resistant sodium channel Nav1.8. Lumbar region dorsal root ganglia (DRG), trigeminal ganglia, and nodose ganglia were dissected from mice (3 mice were pooled/sample). Highly red fluorescent neurons were Facs purified, RNA extracted, and processed for microarray analysis.
Project description:The goal of this study was to analyze global gene expression in FACS purified Nav1.8 lineage sensory neurons, which include nociceptor neurons that detect damaging/noxious stimuli, following peripheral inflammation by intraplantar injection of Complete Freund's Adjuvant (CFA) or Sciatic Nerve Injury (SNI) by nerve transection. Nav1.8 Trangsgenic TdTomato+ neurons were purified from Lumbar L4-L6 dorsal root ganglia (DRG) by flow cytometry from mice on the ipsilateral or contralateral sides, following Complete Freund's Adjuvant injection (day 1) or sciatic nerve transection (day 5). Neurons were then analyzed for transcriptional gene expression by microarray analysis.
Project description:The goal of this study was to analyze global gene expression in specific populations of nociceptor sensory neurons, the neurons that detect damaging/noxious stimuli. The dorsal root ganglia (DRG), trigeminal ganglia, and nodose ganglia are anatomically distinct peripheral sensory ganglia that contain nociceptors which innervate skin, gut, lungs, and other distinct organ tissues. We used flow cytometry to purify nociceptors from these ganglia and profiled their global gene expression signatures to compare gene expression between these different anatomically distinct nociceptors.
Project description:Comparison of transcript levels after diphtheria-toxin deletion of the Nav1.8-expressing cells using the cre/loxP system.<br> Pain requires input from nociceptors which are specialised peripheral sensory neurons in dorsal root ganglia (DRG). To explore the nociceptor-specific mRNA profiles, we used microarray analysis to examine the altered repertoire of genes expressed in DRG from mice depleted of Nav1.8-expressing neurons which are mainly nociceptors. To generate the animal, a Nav1.8 knock-in Cre-expressing mouse (Nav1.8-Cre) was used to excise a floxed stop upstream of globally expressed diphtheria toxin A-subunit gene (ROSA26-eGFP-DTA). By crossing heterozygous Cre mice with homozygous toxin-expressing floxed mice, experimental toxin-expressing (DTA) mice, in which DTA expressing nociceptors had been deleted, were generated. 6 DTA mice and 6 litter mate controls were used for microarray analysis. 3 Affymetrix Mouse Genome 430 2.0 Array chips were employed for analysis of the gene transcripts of each conditions.
Project description:We developed an approach to rapidly eliminate the subgroup of sensory neurons expressing the heat-gated cation channel TRPV1 from dissociated rat sensory ganglia using agonist treatment followed by density centrifugation. To identify transcripts predominantly expressed in TRPV1-positive neurons, we compared the transcriptome of all cells within sensory ganglia versus all cells without TRPV1 expressing neurons using RNA-Seq.
Project description:Vagal afferent neurons are thought to convey primarily physiological information, whereas spinal afferents transmit noxious signals from the viscera to the central nervous system. In order to elucidate molecular identities for these different properties, we compared gene expression profiles of neurons located in nodose ganglia (NG) and dorsal root ganglia (DRG) in mice. Intraperitoneal administration of Alexa Fluor-488 conjugated Cholera toxin B allowed identification of neurons projecting to the viscera. Fluorescent neurons in DRG (from T10 to T13) and NG were isolated using laser capture microdissection. Gene expression profiles of visceral afferent neurons, obtained by microarray hybridization, were analysed using multivariate spectral map analysis, SAM algorithm (Significance Analysis of Microarray data) and fold-difference filtering. A total of 1996 genes were found to be differentially expressed in DRG versus NG, including 41 G-protein coupled receptors and 60 ion channels. Expression profiles obtained on laser-captured neurons were contrasted to those obtained on whole ganglia demonstrating striking differences and the need for microdissection when studying visceral sensory neurons because of dilution of the signal by somatic sensory neurons. Furthermore, a detailed catalogue of all adrenergic and cholinergic, GABA, glutamate, serotonin and dopamine receptors, voltage-gated potassium, sodium and calcium channels and transient receptor potential cation channels present in visceral afferents is provided. Our genome-wide expression profiling data provide novel insight into molecular signatures that underlie both functional differences and similarities between NG and DRG visceral sensory neurons. Moreover, these findings will offer novel insight into mode of action of pharmacologic agents modulating visceral sensation. Experiment Overall Design: Three separate experiments were performed. First, 5 whole dorsal root ganglia were compared to 7 whole nodose ganglia. Second, Laser captured visceral neurons derived from 5 dorsal root ganglia and 5 nodose ganglia were compared on MG-U74Av2. Third, Laser captured visceral neurons derived from 9 dorsal root ganglia and 11 nodose ganglia were compared on Mouse430_2.
Project description:Satellite glia are the major glial type found in ganglia of the peripheral nervous system that wrap around cell bodies of sympathetic and sensory neurons that are very diverse. Other than their close physical association with peripheral neurons, little is known about this glial population. Here, we performed single cell RNA sequencing analysis and identified five different populations of satellite glia from sympathetic and sensory ganglia. We identify three shared populations of satellite glia enriched in immune-response genes, immediate-early genes and ion channels/ECM-interactors, respectively. Sensory- and sympathetic-specific satellite glia are differentially enriched for modulators of lipid metabolism. Sensory glia are also specifically enriched for genes involved in glutamate turnover. Further, satellite glia and Schwann cells can be distinguished by unique transcriptional signatures. This study reveals remarkable heterogeneity of satellite glia in the peripheral nervous system.
Project description:Immune responses within barrier tissues are regulated, in part, by nociceptors, specialized peripheral sensory neurons that detect noxious stimuli. Previous work has shown that nociceptor ablation not only alters local responses at peripheral sites of immune challenge, but also within draining lymph nodes (LNs). The mechanism and significance of nociceptor-dependent modulation of LN homeostasis are unknown. Indeed, although sympathetic innervation of LNs is well documented, it has been unclear whether the LN parenchyma itself is innervated by sensory neurons. Here, using a combination of high-resolution imaging, retrograde viral tracing, optogenetics, and single-cell transcriptomics (scRNA-seq), we describe a sensory neuro-immune circuit that is preferentially located in the outermost cortex of skin-draining LNs. Transcriptomic profiling revealed that sensory neurons that innervate LNs are composed of at least four discrete subsets with a predominance of peptidergic nociceptors, an innervation pattern that is distinct from that in the surrounding skin. To identify potential LN-resident communication partners for LN-innervating sensory neurons, we employed scRNA-seq to generate an atlas of all murine LN cells and, based on receptor-ligand expression patterns, nominated candidate target populations among stromal and immune cells. We experimentally validated these inferred connections by comparing scRNA-seq signatures before and after selective optogenetic stimulation of LN-innervating axons. Acute neuronal activation triggered rapid transcriptional changes preferentially in endothelium and other nodal stroma cells, as well as in several innate leukocyte populations. Thus, LNs are monitored by a unique population of sensory neurons that possess profound immunomodulatory potential.