Landscape of human spinal cord cell type diversity at midgestation

Understanding spinal cord generation and assembly is essential to elucidate how motor behavior is controlled and how disorders arise. The cellular landscape of the human spinal cord remains, however, insufficiently explored. Here, we profiled the midgestation human spinal cord with single cell-resolution and discovered, even at this fetal stage, remarkable heterogeneity across and within cell types. Glia displayed diversity related to positional identity along the dorso-ventral and rostro-caudal axes, while astrocytes with specialized transcriptional programs mapped onto distinct histological domains. We discovered a surprisingly early diversification of alpha (α) and gamma (γ) motor neurons that control and modulate contraction of muscle fibers, which was suggestive of accelerated developmental timing in human spinal cord compared to rodents. Together with mapping of disease-related genes, this transcriptional profile of the developing human spinal cord opens new avenues for interrogating the cellular basis of motor control and related disorders in humans.

A Harmonized Atlas of Spinal Cord Cell Types and Their Computational Classification

ABSTRACTSingle cell sequencing is transforming many fields of science but the vast amount of data it creates has the potential to both illuminate and obscure underlying biology. To harness the exciting potential of single cell data for the study of the mouse spinal cord, we have created a harmonized atlas of spinal cord transcriptomic cell types that unifies six independent and disparate studies into one common analysis. With the power of this large and diverse dataset, we reveal spinal cord cell type organization, validate a combinatorial set of markers for in-tissue spatial gene expression analysis, and optimize the computational classification of spinal cord cell types based on transcriptomic data. This work provides a comprehensive resource with unprecedented resolution of spinal cord cell types and charts a path forward for how to utilize transcriptomic data to expand our knowledge of spinal cord biology.

Protein Kinase A Is Involved in Neuropathic Pain by Activating the p38MAPK Pathway to Mediate Spinal Cord Cell Apoptosis

Neuropathic pain is a serious clinical problem to be solved. This study is aimed at investigating protein kinase A (PKA) expression in neuropathic pain and its possible mechanisms of involvement. A neuropathic pain-related gene expression dataset was downloaded from Gene Expression Omnibus, and differentially expressed genes were screened using the R software. cytoHubba was used to screen for hub genes. A spared nerve injury (SNI) rat model was established, and the paw withdrawal threshold was determined using von Frey filaments. Western blotting and immunofluorescence were used to detect the expression and cellular localization, respectively, of key proteins in the spinal cord. Western blot, ELISA, and TUNEL assays were used to detect cell signal transduction, inflammation, and apoptosis, respectively. Pka was identified as a key gene involved in neuropathic pain. After SNI, mechanical allodynia occurred, PKA expression in the spinal cord increased, the p38MAPK pathway was activated, and spinal cord inflammation and apoptosis occurred in rats. PKA colocalized with neurons, astrocytes, and microglia, and apoptotic cells were mainly neurons. Intrathecal injection of a PKA inhibitor not only relieved mechanical hyperalgesia, inflammatory reaction, and apoptosis in SNI rats but also inhibited p38MAPK pathway activation. However, intrathecal injection of a p38MAPK inhibitor attenuated mechanical hyperalgesia, inflammation, and apoptosis, but did not affect PKA expression. In conclusion, PKA is involved in neuropathic pain by activating the p38MAPK pathway to mediate spinal cord cell apoptosis.

Protein kinase A is involved in neuropathic pain by activating the p38MAPK pathway to mediate spinal cord cell apoptosis

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Protein kinase A is involved in neuropathic pain by activating the p38MAPK pathway to mediate spinal cord cell apoptosis

Background: Neuropathic pain is a serious clinical problem to be solved. Protein kinase A (PKA) is widely distributed in the central nervous system and participates in various signal transduction pathways to regulate cell proliferation and apoptosis. However, it is unclear whether PKA is involved in neuropathic pain. This study aimed to investigate PKA expression in neuropathic pain and its possible mechanisms of involvement. Methods: The mRNA expression dataset of neuropathic pain (GSE24982) was downloaded from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) were screened using the R software. DEGs were subjected to Gene Ontology term and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. A protein-protein interaction network was constructed using the STRING database, and the Cytoscape plug-in cytoHubba was used to screen for hub genes. A spared nerve injury (SNI) rat model was established and the paw withdrawal threshold was determined using von Frey filaments. Western blotting and immunofluorescence were used to detect the expression and cellular localization of key proteins in the spinal cord, respectively. Western blotting, ELISA, and TUNEL assays were used to detect cell signal transduction, inflammation, and apoptosis, respectively. Results: Among 449 DEGs and 20 hub genes, PKA was identified as a key gene involved in neuropathic pain. After SNI, mechanical allodynia occurred, PKA expression in the spinal cord increased, the p38MAPK pathway was activated, and spinal cord inflammation and apoptosis occurred in rats. Immunofluorescence staining showed that PKA colocalized with neurons, astrocytes, and microglia, and TUNEL with GFAP, Iba-1, Neun double labeling showed that apoptotic cells were mainly neurons. Intrathecal injection of a PKA inhibitor not only relieved mechanical hyperalgesia, inflammatory reaction, and apoptosis in SNI rats, but also inhibited p38MAPK pathway activation. Intrathecal injection of a p38MAPK inhibitor attenuated mechanical hyperalgesia, inflammatory reaction, and apoptosis, but did not affect PKA expression. Conclusions: PKA is involved in neuropathic pain by activating the p38MAPK pathway to mediate spinal cord cell apoptosis. This study provides novel insights that my aid in the elucidation of the pathogenesis of neuropathic pain.