Project description:The development of next generation cellular and acellular therapies for regenerative repair of the injured spinal cord will benefit from a greater understanding of microenvironment heterogeneity. To address this need, we used genome wide RNA sequencing to illuminate gene expression changes in the spinal cord injury (SCI) epicenter, and in regions above and below, 30 days after contusion-compression (8 g Fejota clip) of the lumbar spinal cord (L1/L3) in adult female C57BL7J mice. Across injury zones, there were more upregulated versus downregulated genes, with the most dynamic changes occurring in the epicenter, followed by the below and above regions. The expression of 52.9% of genes was uniquely changed in epicenter, 6.6% in the below region, and 2.8% in the above region, while 18.3% of differentially expressed genes (DEGs) overlapped across regions. Ingenuity Pathway analysis of epicenter DEGs showed 49 unique pathways, including Type II Diabetes Mellitus, P2Y Purinergic Receptor, Amyotrophic Lateral Sclerosis, JAK family kinases, and pathways related to GABA and Glutamate function. Thyroid Hormone Metabolism II, Serotonin degradation, and Myc-Mediated Apoptosis were enriched in the zone above the epicenter, while the Chondroitin sulfate degradation, the Superpathway of Geranylgeranylipidphosphate and Zymosterol Biosynthesis, and Regulation of Cellular Mechanics by Calpain Proteases were enriched below. There were 100 pathways shared across regions emphasizing fundamental roles for Apoptosis, Cytoskeletal organization, Chemokines, Complement, Prothrombin Activation pathways, Type I Diabetes Mellitus Signaling, and RXR signaling. These findings provide a rich resource of candidate mechanisms for additional validation and the design of targeted therapies to improve recovery after spinal cord injury.
Project description:Spinal cord gives rise to central somatosensation and orchestrates autonomic and motor control. How its cellular diversity achieves physiological functions across sex and along its longitudinal axis and links spinal cord to higher order brain centers remains poorly understood. Here we used retrograde viral tracing with spatial transcriptomics and multiomic profiling of >750k mouse spinal cord neurons to define its output logic and functional cellular repertoire. We identified 70 spinal projection neuron classes that link the spinal cord to hind-, mid-, and forebrain centers implicated in itch, touch, and pain revealing the output wiring logic of the spinal cord. Furthermore, we characterized >500 anatomically and transcriptomically distinct neuron types that revealed extensive (~50%) rostro-caudal cellular specialization as well as first sex specific neuron classes in the spinal cord. Finally, we assembled a neuron-class-to-phenotype map of the structure based on genetically defined interventions. As a result, we deliver an anatomically and functionally annotated cellular atlas of the complete adult mouse spinal cord to guide future interrogation of the organ.
Project description:A major goal of spinal cord injury research is to develop a path to endogenous regeneration. This approach has been heavily informed by animal models of natural regeneration. An unresolved question is whether these models rebuild the spinal cord by exclusively accessing developmental mechanisms of neuron differentiation. To address this question, we contrasted single-cell gene expression during regeneration with stage-matched controls in the conditionally regenerative frog Xenopus tropicalis. We generated an expanded atlas of neuronal diversity, annotating several neurons in Xenopus for the first time. From this atlas, we found that the neuron composition of the developing and regenerating spinal cord differ. So do the strategies employed, which favor waves of early cell-type specific neurite projection and guidance, then later proliferative neurogenesis during regeneration. Low levels of early neurogenesis are then compensated by movement of post-mitotic neurons. Our work highlights the use of distinct developmental versus regenerative paths to heal post-injury.
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:Human iPSC-derived thoracic spinal cord organoids were transplanted into spinal cord injury mice, and spinal cord tissue was collected after 7 weeks. The transplantation resulted in functional recovery and neural circuit remodeling in the injured mice.
Project description:Transcriptome analysis of spinal cord microglia and total spinal cord from Lewis rats intratracheally treated with PBS, neomycin or vancomycin.