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Meriau, P.

Publications and source records attributed to Meriau, P..

5 recordsLinked to original sources

Single-cell transcriptomic atlas of glial cells in adult mouse dorsal root ganglia identifies multipotent progenitors

Sensory ganglia in the peripheral nervous system contain diverse glial populations that modulate sensory signaling, respond to injury and contribute to tissue homeostasis. Satellite glial cells (SGCs) surrounding neuronal soma in dorsal root ganglia (DRG) were suggested to retain developmental potential, but the identity of progenitor cells remains undefined. To capture glial diversity, we assembled a comprehensive single-cell transcriptomic atlas by integrating over 200,000 DRG and sciatic nerve transcriptomes across multiple studies and injury paradigms. High-resolution clustering resolved 28 cell types and demonstrated significant transcriptional heterogeneity within SGCs and Schwann cells, including repair and reactive sub-states. We identified two distinct populations of progenitor cells that reflect different states in the progenitor trajectory. Functionally, progenitor cell numbers increase after injury, and endothelin signaling regulates glial cell proliferation early in development. This integrated DRG and peripheral nerve atlas represents an essential resource for exploring new features of the peripheral nervous system.

neuroscience↗

A Reference Atlas of the Human Dorsal Root Ganglion

Somatosensory perception largely emerges from diverse peripheral sensory neurons whose cell bodies reside in dorsal root ganglia (DRG). Damage or dysfunction of DRG neurons is a major cause of chronic pain and sensory loss. In mice, deep single-cell transcriptomic profiling and genetically defined models have offered important clues into DRG function, but in humans, the cellular and molecular landscape of DRG neurons remains less understood. Here, we constructed a reference cell atlas of the human DRG by profiling transcriptomes of cells and nuclei from 126 donors sampled across cervical, thoracic, and lumbar DRGs. This atlas resolves 22 neuronal subtypes, including known and previously unrecognized subtypes linked to nociception, mechanosensation, thermosensation, and proprioception, as well as 10 types of non-neuronal cells. Cross-species integration, spatial transcriptomics, and microneurography enabled cell-type-specific comparisons of soma size and conduction velocity between species. Human DRG somata are larger across all cell types than their mouse counterparts, and the conduction velocities of human hair follicle innervating A-fibers are faster than in mice, suggesting a functional shift in rapid mechanical detection in humans. This integrated human DRG reference cell atlas provides a resource for exploring new molecular and physiological features of human DRG, which could help identify new strategies for treating chronic pain and other diseases of the peripheral nervous system.

neuroscience↗

Single nucleus multiomic atlas of human dorsal root ganglia reveals the contribution of non-neuronal cell types to pain

Sensory neurons residing in dorsal root ganglia (DRG) transmit sensory information such as pain, itch, touch, pressure and bodily position to the central nervous system. The activity of sensory neurons is regulated by non-neuronal cell types in the DRG, including satellite glial cells (SGCs), immune cells and fibroblasts. Dysregulated gene expression in DRG cells contributes to sensory nervous system disorders such as chronic pain. Understanding the genetic underpinnings of these conditions requires dissecting transcriptional regulation in human tissue. In this study, we profiled transcriptomic and chromatin accessibility landscapes from postmortem human DRG (hDRG) samples at single-nucleus level. We demonstrate that sequencing depth significantly impacts downstream analysis, with deeper sequencing yielding more detected cells and features, improved data integration, refined clustering and annotation, and more accurate scientific interpretations. We identified nine major cell types, defined their molecular signatures, and mapped cis-regulatory landscapes. Integration of gene expression with chromatin accessibility enabled peak-gene association and transcriptional network analyses, revealing transcription factors, their target genes, regulatory elements and potential partners that cooperatively drive cell-type-specific gene expression programs. This integrative approach identified cell types, genes, and cis-regulatory regions potentially driving pain conditions. Our unbiased genome-wide analysis not only recovered known pain-related genes but also highlighted novel candidate genes and regulatory regions implicated in pain mechanisms. Importantly, our results demonstrate that non-neuronal cells, including endothelial cells, fibroblasts, macrophages, and SGCs, play critical roles in pain pathogenesis and should be investigated as therapeutic targets. One Sentence SummaryOur work provides a comprehensive single-nucleus multi-omic atlas of human dorsal root ganglia, uncovering novel cell-type-specific regulatory mechanisms and candidate therapeutic targets for pain, thereby directly advancing translational insights into human sensory disorders and chronic pain pathogenesis.

neuroscience↗

A multi-omic atlas of human autonomic and sensory ganglia implicates cell types in peripheral neuropathies

The human peripheral nervous system (PNS) consists of many ganglia including sympathetic ganglia (SG) and dorsal root ganglia (DRG). These ganglia house the cell bodies of diverse PNS neurons that transmit autonomic and sensory signals, as well as a much larger number of non-neuronal cells. However, the molecular and cellular diversity of these human PNS cell types and their implications in human disease remain elusive. By generating an integrated single-cell multi-omic atlas of human SG and DRG, we provide comprehensive transcriptional and epigenomic landscapes of various cell types in these peripheral ganglia. While the major cell types and their cell-type-specific transcriptional and epigenomic features are similar between human SG and DRG, we identify key differences between SG and DRG cell types. These differences highlight the distinct molecular and cellular mechanisms underlying their specific functions. We also profiled key genomic regulatory networks that govern cell-type-specific gene expression in these peripheral ganglia. Moreover, by mapping the expression and chromatin accessibility of disease-associated genes in human SG and DRG, we identify cell types that may underlie various peripheral neuropathies. This atlas serves as a valuable resource for understanding the intricate cell-type-specific molecules and interactions in the human PNS and their implications in human health and diseases.

neuroscience↗

Frataxin deficiency in proprioceptive neurons is causal to inflammatory and glial responses in dorsal root ganglia

Friedreich ataxia (FA), the most common recessive hereditary ataxia, is an early-onset neurodegenerative disease characterized by pathological changes occurring first in the peripheral dorsal root ganglia (DRG), with loss of the large sensory proprioceptive neurons, leading to ganglionopathy and proprioceptive deficits. FA is caused by a mutation in frataxin gene (Fxn), leading to reduced expression of frataxin protein (FXN), an essential ubiquitous mitochondrial protein. Most research has focused on the pathophysiological involvement of proprioceptors. However, in recent years, neuroinflammation is increasingly recognized as an integral and critical contributor in FA pathogenesis. Furthermore, it has also recently been shown a primary reactivity of satellite glial cells (SGCs; glia tightly enwrapping proprioceptor cell bodies), suggesting a role of inflammation and SGC responses in the destruction of proprioceptors in FA patients DRGs. It remains unclear to what extent the increase in DRG macrophage response and/or SGC reactivity may contribute to FA phenotype. Therefore, it is important to fully study and understand the mechanism of proprioceptor-macrophages-SGC interactions and their regulations. Exploring relationship between these three cell types has profound implications for breaking through the limitation of treatment of FA. Here we asked whether FXN deficiency selectively in DRG proprioceptive neurons is sufficient to cause inflammatory and glial responses found in patients DRG. We used RNA profiling, bioinformatics signaling network and pathway analysis, combined with immunohistochemistry and behavioral experiments to reveal some genes, signaling pathways in macrophages and SGCs that may represent potential biomarkers of the disease. Our study revealed that proprioceptor FXN deficiency causes major changes in inflammatory macrophage and SGC gene transcription as well as macrophage and SGC number, highlighting molecular and cellular pathways that were sequentially altered, thus representing temporal signatures of FA ganglionopathy progression.

neuroscience↗