Comprehensive analysis of Long non-coding RNA expression in dorsal root ganglion reveals cell type specificity and dysregulation following nerve injury [rodent DRG]
Ontology highlight
ABSTRACT: Dorsal root ganglion (DRG) neurons provide connectivity between peripheral tissues and spinal cord. Transcriptional plasticity within DRG sensory neurons after peripheral nerve injury contributes to nerve repair but also leads to maladaptive plasticity, including the development of neuropathic pain. This study presents tissue and neuron specific expression profiling of both known and novel Long Non-Coding RNAs (LncRNAs) in rodent DRG following nerve injury. We have identified a large number of novel LncRNAs expressed within rodent DRG, a minority of which were syntenically conserved between mouse and rat and which including both- intergenic and antisense LncRNAs. We have also identified neuron type-specific LncRNAs in mouse DRG, and LncRNAs that are expressed in human IPS cell-derived sensory neurons. We show significant plasticity in LncRNA expression following nerve injury, which in mouse is strain dependant. This resource is publicly available and will aid future studies of DRG neuron identity and the transcriptional landscape in both naïve and injured DRG.
Project description:Dorsal root ganglion (DRG) neurons provide connectivity between peripheral tissues and spinal cord. Transcriptional plasticity within DRG sensory neurons after peripheral nerve injury contributes to nerve repair but also leads to maladaptive plasticity, including the development of neuropathic pain. This study presents tissue and neuron specific expression profiling of both known and novel Long Non-Coding RNAs (LncRNAs) in rodent DRG following nerve injury. We have identified a large number of novel LncRNAs expressed within rodent DRG, a minority of which were syntenically conserved between mouse and rat and which including both- intergenic and antisense LncRNAs. We have also identified neuron type-specific LncRNAs in mouse DRG, and LncRNAs that are expressed in human IPS cell-derived sensory neurons. We show significant plasticity in LncRNA expression following nerve injury, which in mouse is strain dependant. This resource is publicly available and will aid future studies of DRG neuron identity and the transcriptional landscape in both naïve and injured DRG.
Project description:Primary sensory neurons with cell soma in dorsal root ganglia (DRG) project axons in both the peripheral nervous system and the spinal cord. Whereas the peripheral axon can regenerate after injury, the central axon cannot, providing an opportunity to identify the mechanisms that promote axon regeneration. Using this system, multiple intrinsic mechanisms operating in sensory neurons have been shown to promote axon regeneration. Peripheral sensory neurons also benefit from a supportive environment. In particular, macrophages play important roles in nerve regeneration by clearing debris and regulating Schwann cell function at the site of injury in the nerve. Nerve macrophages have been characterized at the molecular level and derive for the most part from infiltrating monocytes. However, the role and origin of macrophages in the DRG remains poorly understood. Following a 14-days treatment with a CSF1R inhibitor, less than 10% of macrophages remained in the DRG. Recovery from this treatment resulted in a dramatic macrophage repopulation, with the number of DRG macrophages reaching level similar to untreated mice three days post injury. These repopulated DRG macrophages contribute to promote axon regeneration. Our scRNA-seq analysis allow in-depth characterization of the repopulated DRG macrophages in response to nerve injury. These data will provide a better understanding of DRG macrophages and the molecular mechanisms by which they contribute to peripheral nerve repair. These studies may lead to new potential targets to promote axon regeneration.
Project description:We used single cell multi-omics method to simultaneously profiled both DNA methylome and mRNA transcriptome from single DRG sensory neurons under either control or peripheral nerve injury condition.
Project description:Peripheral nerve injury could lead to chronic neuropathic pain. Understanding transcriptional changes induced by nerve injury could provide fundamental insights into the complex pathogenesis of neuropathic pain. Gene expression profiles of dorsal root ganglia (DRG) under neuropathic pain condition have been studied. However, little is known about transcriptomic changes in individual DRG neurons after peripheral nerve injury. Here we performed single-cell RNA sequencing on dissociated mouse DRG cells after spared nerve injury (SNI). In addition to DRG neuron types also found under normal conditions, we identified three SNI-induced neuron clusters (SNIICs) characterized by the expression of Atf3/Gfra3/Gal (SNIIC1), Atf3/Mrgprd (SNIIC2) and Atf3/S100b/Gal (SNIIC3). These SNIICs were originated from Cldn9+/Gal+, Mrgprd+ and Trappc3l+ DRG neuron types. Interestingly, SNIIC2 was switched to SNIIC1 by increasing Gal and reducing Mrgprd expression 2 days after nerve injury. Inferring the gene regulatory networks underlying nerve injury, we revealed that activated transcription factor Atf3 and Egr1 in SNIICs could enhance Gal expression while activated Cpeb1 in SNIIC2 might suppress Mrgprd expression within 2 days after SNI. Furthermore, we screened the transcriptomic changes in the development of neuropathic pain to identify the potential analgesic targets. We revealed that the expression of cardiotrophin-like cytokine factor 1, which could activate the astrocytes in the dorsal horn of spinal cord, was increased in SNIIC1 neurons and contributed to SNI-induced mechanical allodynia. Therefore, our results provide a new framework to understand the changes in neuron types and the dynamics of molecular and cellular mechanisms underlying the development of neuropathic pain.
Project description:Retrograde signaling from axon to soma activates intrinsic regeneration mechanisms in lesioned peripheral sensory neurons; however, the links between axonal injury signaling and the cell body response are not well understood. Here, we used phosphoproteomics and microarrays to implicate ~900 phosphoproteins in retrograde injury signaling in rat sciatic nerve axons in vivo and ~4500 transcripts in the in vivo response to injury in the dorsal root ganglia. Computational analyses of these data sets identified ~400 redundant axonal signaling networks connected to 39 transcription factors implicated in the sensory neuron response to axonal injury. Experimental perturbation of individual overrepresented signaling hub proteins, including Abl, AKT, p38, and protein kinase C, affected neurite outgrowth in sensory neurons. Paradoxically, however, combined perturbation of Abl together with other hub proteins had a reduced effect relative to perturbation of individual proteins. Our data indicate that nerve injury responses are controlled by multiple regulatory components, and suggest that network redundancies provide robustness to the injury response Microarrays were run on mRNA extracted from adult rat L4 and L5 DRGs cells after 1,3,8,12,16,18,24, and 28 hours after a sciatic nerve (proximal and distal) lesion.
Project description:To elucidate transcriptional responses in peripherally injured neurons, we performed RNA-seq of dorsal root gangliona (DRG) sensory neurons at 1 and 5 days following sciatic nerve injury.
Project description:Transcriptional events leading to outgrowth of neuronal axons have been intensively studied, but the role of translational regulation in this process is not well understood. Here we use translatome analyses by ribosome pull-down and protein synthesis characterization by metabolic isotopic labeling to study nerve injury and axon outgrowth proteomes in rodent dorsal root ganglia (DRG) and sensory neurons. We identify over 1600 gene products that are primarily translationally regulated in DRG neurons after nerve injury, many of which contain a 5’UTR CERT motif, implicating the translation initiation factor Eif4e in the injury response. We further identified approximately 200 proteins that undergo robust de novo synthesis in the initial stages of axon growth. ApoE is one of the highly synthesized proteins in neurons, and inhibition of its signaling affects axon outgrowth. These findings suggest prominent roles for translational regulation in initial stages of the neuronal injury response and axon extension.
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:Preconditioning nerve injury drives pro-regenerative perineuronal macrophage activation in dorsal root ganglia (DRG). The present study reports that oncomodulin (ONCM) is produced from the regeneration-associated macrophages (RAMs) and strongly influences regeneration of DRG sensory axons. ONCM in macrophages was necessary to produce RAMs in the in vitro model of neuron-macrophage interaction and played an essential role in for preconditioning-induced neurite outgrowth. In order to gain insight on potential mechanisms downstream of ONCM for potent neurite outgrowth activity, we performed RNA-seq using cultured DRG neurons treated with ONCM.
Project description:We reported the gene expression analysis of different types of sensory neuron with peripheral nerve transection treatment on single cell level. We found substantial variation between myelinated large diameter neurons and small diameter nonpeptidergic nociceptors, in both terms of regeneration response genes regulation as well as fraction of cells respond to nerve injury.