Spatial transcriptomics and single-nucleus RNA-sequencing reveal a transcriptomic atlas of human spinal cord [Spinal snRNA-seq]
Ontology highlight
ABSTRACT: Despite the recognized importance of the spinal cord in sensory processing, motor behaviors, and neural diseases, the underlying organization of neuronal clusters and their spatial location remain elusive. Recently, several studies have attempted to define the neuronal types and functional heterogeneity in the spinal cord using single-cell or single-nucleus RNA sequencing in animal models or developing humans. However, molecular evidence of cellular heterogeneity in the adult human spinal cord is limited. Here, we classified spinal cord neurons into 21 subclusters and determined their distribution from nine human donors using single-nucleus RNA sequencing and spatial transcriptomics. Moreover, we compared the human findings with previously published single-nucleus data of the mouse adult spinal cord, which revealed an overall similarity in the neuronal composition of the spinal cord between the two species while simultaneously highlighting some degree of heterogeneity. Additionally, we examined the sex differences in the spinal neuronal subclusters. Several genes, such as SCN10A and HCN1, showed sex differences in motor neurons. Finally, we classified human DRG neurons using spatial transcriptomics and explored the putative interactions between DRG and spinal cord neuronal subclusters. In summary, these results illustrate the complexity and diversity of spinal neurons in humans and provide an important resource for future research to explore the molecular mechanisms underlying spinal cord physiology and diseases.
Project description:Despite the recognized importance of the spinal cord in sensory processing, motor behaviors, and neural diseases, the underlying organization of neuronal clusters and their spatial location remain elusive. Recently, several studies have attempted to define the neuronal types and functional heterogeneity in the spinal cord using single-cell or single-nucleus RNA sequencing in animal models or developing humans. However, molecular evidence of cellular heterogeneity in the adult human spinal cord is limited. Here, we classified spinal cord neurons into 21 subclusters and determined their distribution from nine human donors using single-nucleus RNA sequencing and spatial transcriptomics. Moreover, we compared the human findings with previously published single-nucleus data of the mouse adult spinal cord, which revealed an overall similarity in the neuronal composition of the spinal cord between the two species while simultaneously highlighting some degree of heterogeneity. Additionally, we examined the sex differences in the spinal neuronal subclusters. Several genes, such as SCN10A and HCN1, showed sex differences in motor neurons. Finally, we classified human DRG neurons using spatial transcriptomics and explored the putative interactions between DRG and spinal cord neuronal subclusters. In summary, these results illustrate the complexity and diversity of spinal neurons in humans and provide an important resource for future research to explore the molecular mechanisms underlying spinal cord physiology and diseases.
Project description:Despite the recognized importance of the spinal cord in sensory processing, motor behaviors, and neural diseases, the underlying organization of neuronal clusters and their spatial location remain elusive. Recently, several studies have attempted to define the neuronal types and functional heterogeneity in the spinal cord using single-cell or single-nucleus RNA sequencing in animal models or developing humans. However, molecular evidence of cellular heterogeneity in the adult human spinal cord is limited. Here, we classified spinal cord neurons into 21 subclusters and determined their distribution from nine human donors using single-nucleus RNA sequencing and spatial transcriptomics. Moreover, we compared the human findings with previously published single-nucleus data of the mouse adult spinal cord, which revealed an overall similarity in the neuronal composition of the spinal cord between the two species while simultaneously highlighting some degree of heterogeneity. Additionally, we examined the sex differences in the spinal neuronal subclusters. Several genes, such as SCN10A and HCN1, showed sex differences in motor neurons. Finally, we classified human DRG neurons using spatial transcriptomics and explored the putative interactions between DRG and spinal cord neuronal subclusters. In summary, these results illustrate the complexity and diversity of spinal neurons in humans and provide an important resource for future research to explore the molecular mechanisms underlying spinal cord physiology and diseases.
Project description:Despite the recognized importance of the spinal cord in sensory processing, motor behaviors, and/or neural diseases, the underlying organization of neuronal clusters remain elusive. Recently, several studies have attempted to define the neuronal types and functional heterogeneity in the spinal cord using single-cell and/or single-nucleus RNA-sequencing in various animal models. However, molecular evidence of neuronal heterogeneity in the human spinal cord has not yet been established. Here, we sought to classify spinal cord neurons from human donors using high-throughput single-nucleus RNA-sequencing. The functional heterogeneity among the identified cell types and signaling pathways that connect neuronal subtypes were explored. Moreover, we compared the transcriptional patterns obtained in human samples with previously published single-cell transcriptomic profiles of the mouse spinal cord. As a result, we generated the first comprehensive transcriptomic atlas of human spinal cord neurons and defined 18 neuronal clusters. In addition to identifying new and functionally distinct neuronal subtypes, our results also provide novel marker genes for previously described neuronal types. The comparison with mouse transcriptomic profiles revealed an overall similarity in the cellular composition of the spinal cord between the two species, while simultaneously highlighting some degree of heterogeneity. In summary, these results illustrate the complexity and diversity of neuronal types in the human spinal cord and provide an important resource for future research to explore the molecular mechanisms underlying spinal cord physiology and diseases.
Project description:Motor neurons are a rare neuronal subtype in the adult spinal cord. We performed single-nucleus RNA sequencing on nuclei extracted from adult human spinal cord and describe the transcriptional heterogeneity.
Project description:Glial cells are present throughout the entire nervous system and paly a crucial role in regulating physiological and pathological functions, such as infections, acute injuries and chronic neurodegenerative disorders. The glial cells mainly include astrocytes, microglia, and oligodendrocytes in the central nervous system (CNS), and satellite glial cells (SGCs) in the peripheral nervous system (PNS). Although the glial subtypes and functional heterogeneity is relatively well understood in mice by recent studies using single-cell or single-nucleus RNA-sequencing, no evidence yet has elucidate the transcriptomic profiles of glia cells in PNS and CNS. Here, we used high-throughput single-nucleus RNA-sequencing to map the cellular and functional heterogeneity of SGCs in human dorsal root ganglion (DRG), and astrocytes, microglia, and oligodendrocytes in human spinal cord. In addition, we compared the human findings with previous single-nucleus transcriptomic profiles of glial cells from mouse DRG and spinal cord. This work will comprehensively profile glial cells heterogeneity and will provide a powerful resource for probing the cellular basis of human physiological and pathological conditions related to glial cells.
Project description:Although axon regeneration can now be induced experimentally across anatomically complete spinal cord injury (SCI), restoring meaningful function after such injuries has been elusive. This failure contrasts with the spontaneous, naturally occuring repair that restores walking after severe but incomplete SCI. Here, we applied projection-specific and comparative single-nucleus RNA sequencing to uncover the transcriptional phenotype and connectome of neuronal subpopulations involved in natural spinal cord repair. We identified a molecularly defined population of excitatory projection neurons in the thoracic spinal cord that extend axons to the lumbar spinal cord where walking execution centers reside. We show that regrowing axons from these specific neurons across anatomically complete SCI and guiding them to reconnect with their appropriate target region in the lumbar spinal cord restores walking in mice. These results demonstrate that mechanism-based repair strategies that recapitulate the natural topology of molecularly defined neuronal subpopulations can restore neurological functions. Expanding this principle to different classes of neurons across the central nervous system may unlock the framework to achieve complete repair of the injured spinal cord.
Project description:Purpose: Nerve injury-induced hyperactivity of primary sensory neurons in the dorsal root ganglion (DRG) contributes critically to chronic pain development, but its underlying mechanisms remain incompletely understood. Chronic neuropathic pain has a clear epigenetic component, however, most studies so far have focused on histone modifications. We determined changes of DNA methylation in the rat DRG, spinal cord, and prefrontal cortex after spinal nerve ligation (SNL).
Project description:Purpose: Nerve injury-induced hyperactivity of primary sensory neurons in the dorsal root ganglion (DRG) contributes critically to chronic pain development, but its underlying mechanisms remain incompletely understood. Chronic neuropathic pain has a clear epigenetic component, however, most studies so far have focused on histone modifications. We determined changes of DNA methylation in the rat DRG, spinal cord, and prefrontal cortex after spinal nerve ligation (SNL).
Project description:Adult zebrafish have the ability to recover from spinal cord injury and exhibit re-growth of descending axons from the brainstem to the spinal cord. We performed gene expression analysis using microarray to find damage-induced genes after spinal cord injury, which shows that Sox11b mRNA is up-regulated at 11 days after injury. However, the functional relevance of Sox11b for regeneration is not known. Here, we report that the up-regulation of Sox11b mRNA after spinal cord injury is mainly localized in ependymal cells lining the central canal and in newly differentiating neuronal precursors or immature neurons. Using an in vivo morpholino-based gene knockout approach, we demonstrate that Sox11b is essential for locomotor recovery after spinal cord injury. In the injured spinal cord, expression of the neural stem cell associated gene, Nestin, and the proneural gene Ascl1a (Mash1a), which are involved in the self-renewal and cell fate specification of endogenous neural stem cells, respectively, is regulated by Sox11b. Our data indicate that Sox11b promotes neuronal determination of endogenous stem cells and regenerative neurogenesis after spinal cord injury in the adult zebrafish. Enhancing Sox11b expression to promote proliferation and neurogenic determination of endogenous neural stem cells after injury may be a promising strategy in restorative therapy after spinal cord injury in mammals. Spinal cord injury or control sham injury was performed on adult zebrafish. After 4, 12, or 264 hrs, a 5 mm segment of spinal cord was dissected and processed (as a pool from 5 animals) in three replicate groups for each time point and treatment.
Project description:The developmental maturation of a neuron requires the completion of neuronal polarization preceding the formation of a synapse. Whether neuronal polarization marks the decline in growth competence in the injured mammalian adult nervous system remains elusive. Here we show that gene expression and epigenetic signatures associated with the regenerative growth ability of dorsal root ganglia (DRG) sensory neurons are lost during the transition from a non-polarized to a polarized state. The transcriptional co-factor Cited2 was found to be epigenetically upregulated in immature DRG and following a regenerative injury, but it remained unchanged by a non-regenerative spinal cord injury (SCI). Next, Cited2 was overexpressed in DRG neurons in a model of SCI in mice where it promoted sensory axon growth and reversed the gene expression signatures associated with neuronal maturation. Importantly, Cited2 expression stirred the maturation of DRG neurons towards a non-polarized state. Together, these data suggest that the transition from a non-polarized to a polarized state marks the reversible loss of the regenerative ability of a neuron, thus paving the way to targeted repair strategies relying on neuronal de-maturation.