Biology subjects

Sankaranarayanan, I.

Publications and source records attributed to Sankaranarayanan, I..

At least 19 recordsLinked to original sources

bioRxiv2026

History of opioid use disorder correlates with altered neuroimmune signatures in the human dorsal root ganglia

Understanding mechanisms for the negative reinforcing effects of opioids are fundamental to improving patient care. Using human dorsal root ganglia (DRG) from donors with and without opioid use disorder (OUD), we set out to examine functional and molecular correlates of chronic opioid use. At a molecular level, we detected disrupted immune signatures throughout cells in the peripheral nervous system (PNS), spanning glial-neuroimmune interactions to changes in non-neuronal senescence. At the physiological level these changes are paired with sensitization of DRG sensory neurons. Our findings reveal a neuro-inflammatory state in the PNS of individuals with OUD. Targeting therapeutics towards these PNS-based mechanisms could be an approach to alleviating the negative reinforcing effects of opioids.

neuroscience↗

bioRxiv2026

NaV1.7-dependent peripheral sensitization drives chronic pain in Parkinson's disease

Pain is among the most prevalent and disabling nonmotor symptoms of Parkinson's disease (PD), yet its mechanisms remain poorly defined and effective treatments are limited. Safinamide is one of the few drugs reported to improve pain in PD, but the mechanism underlying this effect is unknown. Here, we show that nigrostriatal neurodegeneration produces persistent hyperexcitability of primary sensory neurons associated with dysregulation of the voltage-gated sodium channel NaV1.7. In a brain-restricted 6-hydroxydopamine (6-OHDA) model, small-diameter dorsal root ganglion (DRG) neurons exhibited increased sodium current density and altered voltage-dependent inactivation, with the excess current eliminated by selective NaV1.7 blockade. Safinamide directly inhibited a NaV1.7-dependent component of sensory neuron sodium current and reversed established pain-like behaviors. Pharmacological disruption of NaV1.7 regulation by collapsin response mediator protein 2 (CRMP2) normalized DRG hyperexcitability and reversed mechanical and thermal hypersensitivity, whereas genetic disruption of the NaV1.7 CRMP2 regulatory sequence prevented the development of 6-OHDA-induced pain-like behaviors for up to 30 weeks despite preservation of the Parkinsonian motor phenotype. Transcriptomic profiling of human PD DRGs revealed limited global transcriptional remodeling with selective alterations in genes associated with sensory neuron excitability. Together, these findings demonstrate that dopaminergic neurodegeneration initiated within the brain is sufficient to drive persistent peripheral sensory neuron dysfunction and identify CRMP2-dependent regulation of NaV1.7 as a therapeutic target for Parkinsonian pain.

neuroscience↗

bioRxiv2026

Live cell imaging reveals paclitaxel-induced lysosome motility and function disruption in DRG neurons

Lysosomal trafficking and homeostasis are biological functions that are pivotal for DRG neurons, given their metabolic demands and extremely long axons. Previous studies indicate that lysosomal signaling is altered in a mouse model of chemotherapy-induced peripheral neuropathy (CIPN) and that blocking mitogen activated protein kinase-associated kinase (MNK1/2) signaling can alleviate pain behaviors in CIPN. Here, we investigated lysosome dynamics and lysosome-associated signaling in a mouse model of CIPN induced by paclitaxel (PTX), a chemotherapeutic agent used for various types of cancer. Using spinning disk super-resolution microscope (SPINSR), we demonstrate that PTX treatment in vivo causes reduced lysosome motility observed in vitro. PTX likewise drives the accumulation of Sequestosome 1 (SQSTM1), also known as P62, in cultured mouse DRG neurons, indicating lysosomal dysfunction in DRG neurons. The transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, was also upregulated in the nucleus of cultured mouse DRG neurons treated with PTX. In line with this, increased lysosomal-associated membrane protein 1 (LAMP1) expression was observed in PTX-treated mice. Given that our previous work demonstrated PTX treatment increases MNK1/2-eIF4E signaling in DRG neurons, we examined whether MNK1/2 inhibition could rescue lysosomal dysfunction. Treatment with Tomivosertib (eFT508), a potent MNK1/2 inhibitor, restored P62 levels in DRG neurons of PTX-treated mice and reduced TFEB in DRG treated in vitro. To establish translation relevance, we further show that PTX elevates phosphorylated eiF4E (p-eIF4E) in human DRG neurons, and concurrent eFT508 administration attenuates this effect. Collectively, these findings indicated that PTX disrupts lysosome trafficking and biogenesis, and that MNK inhibition with eFT508 restores lysosomal signaling and can serve as a neuroprotective strategy for CIPN.

neuroscience↗

bioRxiv2026

Satellite microglia-like cells in human dorsal root ganglia and changes with diabetic neuropathy

Phagocytic and immune-like cells have been observed in the satellite envelope of neuronal somata in peripheral sensory ganglia of many species for several decades. These cells likely play an important role in normal function of sensory neurons and they may also play an important role in neuronal dysfunction and neurodegeneration seen with neuropathy. Recent findings have described a satellite macrophage population transcriptomically similar to microglia in peripheral ganglia of some mammalian species. The function of these cells, and the mechanisms by which they may influence neurons in neuropathy are unclear. We sought to understand the phenotype and localization of these cells in the human dorsal root ganglion (hDRG) using large-scale single nucleus and spatial transcriptomic datasets from individuals with and without a history of peripheral diabetic neuropathy. We observed a large population of macrophages that express classical microglia makers such as TMEM119 and P2RY12 in the hDRG, as previously described. Our findings confirm that these microglia-like cells (MLCs) localize to the satellite envelope around neuronal somata, yet are transcriptomically distinct from all glial cell types characterized in the hDRG. These MLCs exhibit changes in abundance and localization with diabetic painful neuropathy (DPN) in both the hDRG and sural nerves suggesting that they are not exclusively localized to the DRG. We conclude that microglia-like cells are likely the resident tissue macrophage (RTM) of the hDRG, and perhaps the peripheral nervous system (PNS) given their localization to the sural nerve and other ganglia, where they are predicted to regulate homeostatic neuronal functions and response to injury. HighlightsO_LIMLCs are likely the RTM of hDRGs C_LIO_LIMLCs localize to the satellite envelope and recede with Nageotte nodule formation C_LIO_LIMLC activation state and signaling shift with diabetic neuropathy C_LIO_LIMLCs are also present in other ganglia and sural nerve C_LI

neuroscience↗

bioRxiv2026

Progressive neurodegeneration in human dorsal root ganglion from diabetes to painful neuropathy

Diabetic painful neuropathy (DPN) is characterized by neuropathic pain accompanied by loss of sensory function. We hypothesized that neurodegeneration in the dorsal root ganglion (DRG) could underlie DPN progression. To address this question, we performed multi-omic evaluation on DRGs from otherwise healthy organ donors, donors with diabetes but no neuropathy, and donors with clinically diagnosed DPN. We discovered that the first stages of neurodegeneration begin early in diabetes before the onset of DPN, with Nageotte nodule formation accompanied by apoptotic gene expression and decreased proportion of specific populations of A-fibers in DPN with remodeling of non-neuronal cells. Our findings define DPN as a neurodegenerative disorder of the DRG, identify molecular markers of disease stage, and highlight the need for early intervention to prevent irreversible neurodegeneration.

neuroscience↗

bioRxiv2025

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↗

bioRxiv2025

Peripheral nerve-targeting and pain-promoting transcriptomic signatures in early Guillain-Barr&eacute syndrome

Guillain-Barre syndrome (GBS) is an autoimmune disorder that causes weakness, sensory loss, autonomic dysfunction, and chronic neuropathic pain. The mediators responsible for driving early autoimmune injury in the most common GBS variant, acute inflammatory demyelinating polyradiculoneuropathy (AIDP), remain incompletely understood. We performed single-cell and bulk RNA sequencing on peripheral blood mononuclear cells collected from early untreated AIDP-variant GBS patients and healthy controls to comprehensively deduce leukocyte transcriptome alterations and predict disease- and pain-driving interactions between pathogenic leukocytes and peripheral nervous system cells. We found that classical, intermediate, and non-classical monocytes were expanded and upregulated genes associated with type I and II interferons, JAK/STAT signaling, and NLRP3 inflammasome engagement. CD8+ T cells were highly proliferative and likewise upregulated JAK/STAT signaling. CD4+FOXP3+ regulatory T cells upregulated PRDM1 and CD74 in a signature that may indicate functional exhaustion. A subpopulation of highly activated intermediate monocytes upregulated genes related to angiogenesis and oncostatin M. Differential expression-based cell-cell interaction analysis between GBS leukocytes, Schwann cells, and sensory neurons predicted engagement of ligand-receptor pairs with nerve integrity and pain functions, including epiregulin, interferon-beta, adrenomedullin, clusterin, IL-6, IL-15, and CCL4. Functional validation demonstrated that CCL4 sensitizes human sensory neurons in vitro. These results unearth molecular interactions by which specific leukocyte populations in AIDP-variant GBS may participate in peripheral nerve injury and drive neuropathic pain. Many of these targets may be amenable to therapeutic modulation using available approved and investigational drugs, potentially providing drug repurposing opportunities.

neuroscience↗

bioRxiv2025

Meteorin resolves nociceptive hypersensitivity by reducing connexin-mediated coupling in satellite glial cells

Neuropathic pain, a persistent condition arising from injury to the nervous system, involves complex interactions between neurons and non-neuronal cells, including satellite glial cells (SGCs) in the dorsal root ganglia (DRG). In this study, we examined the glial-targeting effects of meteorin, a neurotrophic protein with gliogenic properties, using mouse models of neuropathic and inflammatory pain. Systemic meteorin administration reversed mechanical hypersensitivity across diverse neuropathic and inflammatory pain models, with therapeutic effects persisting beyond the treatment period. We identified SGCs as the principal site of meteorin expression and action in the DRG, where it selectively activated SGCs and altered their functional state. Proteomic profiling revealed meteorin-mediated downregulation of gap junction proteins in SGCs, particularly connexin 43, which was corroborated by immunohistochemical analyses. Functional assessments demonstrated that meteorin treatment normalized injury-induced increases in intercellular coupling between SGCs, establishing a mechanistic link between glial network modulation and pain resolution. These findings identify meteorin as a regulator of SGC communication through connexin-dependent mechanisms. The sustained therapeutic effects and multi-model efficacy highlight meteorin as a potential intervention for neuropathic pain while advancing our understanding of SGC plasticity in sensory processing.

neuroscience↗

bioRxiv2025

Mapping satellite glial cell heterogeneity reveals distinct spatial organization and signifies functional diversity in the dorsal root ganglion

Satellite glial cells (SGCs) envelop the somata, axon hillock, and initial axon segment of sensory neurons in the dorsal root ganglia (DRG), playing a critical role in regulating the neuronal microenvironment. While DRG neurons have been extensively studied and classified based on size, molecular markers, and functional characteristics, very little is still known about SGC heterogeneity and its potential implications on sensory processing in the DRG. Single cell transcriptional analyses have proposed the existence of SGC subtypes, yet in situ validation, spatial distribution, and potential functional implications of such subtypes are still largely unexplored. Here, we present the first comprehensive in situ characterization of SGC heterogeneity within the mouse DRG. By integrating single-cell RNA sequencing with immunohistochemistry, in situ hybridization, and advanced imaging techniques, distinct SGC subclusters were identified, validated, and spatially mapped within their native anatomical context. We visually identify four distinct subpopulations: 1) a predominant population of perisomatic SGC sheaths defined by the expression of marker proteins traditionally used to characterize the entire SGC population, including FABP7, KIR4.1, GS, and CX43. 2) OCT6+ SGCs occasionally being found in mosaic perisomatic sheaths, and consistently associated with axonal glomeruli, primarily ensheathing initial segment axon. 3) SCN7A+ SGCs, exhibiting no/low expression of traditional SGC markers and forming specialized homogenous sheaths around non-peptidergic neuron subtypes, implicating their potential role in pruritic (itch-related) conditions. 4) Interferon response gene-expressing SGCs, responding to Herpes Simplex Virus infection, suggesting potential involvement in antiviral protection. Finally, we investigate human DRG and find an inner perisomatic SGC layer surrounded by an outer SGC layer, with traditional and novel markers distinctively distributed between the two layers. Our results provide novel insight into SGC heterogeneity in the DRG and suggests distinct functional properties for such subtypes of relevance for the neuronal microenvironment.

neuroscience↗

bioRxiv2025

Expansion of OSMR expression and signaling in the human dorsal root ganglion links OSM to neuropathic pain

RNA sequencing studies on human dorsal root ganglion (hDRG) from patients suffering from neuropathic pain show upregulation of OSM, linking this IL-6 family cytokine to pain disorders. In mice, however, OSM signaling causes itch behaviors through a direct effect on its cognate receptor expressed uniquely by pruriceptive sensory neurons. We hypothesized that an expansion in function of OSM-OSM receptor (OSMR) in sensory disorders in humans could be explained by species differences in receptor expression and signaling. Our in situ hybridization and immunohistochemical findings demonstrate broad expression of OSMR in DRG nociceptors and afferent fibers innervating the superficial and deep skin of humans. In patch-clamp electrophysiology, OSM directly activates human sensory neurons engaging MAPK signaling to promote action potential firing. Using CRISPR editing we show that OSM activation of MAPK signaling is dependent on OSMR and not LIFR in hDRG. Bulk, single-nuclei, and single-cell RNA-seq of OSM-treated hDRG cultures reveal expansive similarities in the transcriptomic signature observed in pain DRGs from neuropathic patients, indicating that OSM alone can orchestrate transcriptomic signatures associated with pain. We conclude that OSM-OSMR signaling via MAPKs is a critical signaling factor for DRG plasticity that may underlie neuropathic pain in patients.

neuroscience↗

bioRxiv2025

Single-cell characterization of the human C2 dorsal root ganglion recovered from C1-2 arthrodesis surgery: implications for neck pain

Neurons in the dorsal root ganglion (DRG) receive and transmit sensory information from the tissues they innervate and from the external environment. Upper cervical (C1-C2) DRGs are functionally unique as they receive input from the neck, head, and occipital cranial dura, the latter two of which are also innervated by the trigeminal ganglion (TG). The C2 DRG also plays an important role in neck pain, a common and disabling disorder that is poorly understood. Advanced transcriptomic approaches have significantly improved our ability to characterize RNA expression patterns at single-cell resolution in the DRG and TG, but no previous studies have characterized the C2 DRG. Our aim was to use single-nucleus and spatial transcriptomic approaches to create a molecular map of C2 DRGs from patients undergoing arthrodesis surgery with ganglionectomy. Patients with acute (<3 months) or chronic ([≥]3 months) neck pain were enrolled and completed patient-reported outcomes and quantitative sensory testing prior to surgery. C2 DRGs were characterized with bulk, single nucleus, and spatial RNA sequencing technologies from 22 patients. Through a comparative analysis to published datasets of the lumbar DRG and TG, neuronal clusters identified in both TG and DRG were identified in the C2 DRG. Therefore, our study definitively characterizes the molecular composition of human C2 neurons and establishes their similarity with unique characteristics of subsets of TG neurons. We identified differentially expressed genes in endothelial, fibroblast and myelinating Schwann cells associated with chronic pain, including FGFBP2, C8orf34 and EFNA1 which have been identified in previous genome and transcriptome wide association studies (GWAS/TWAS). Our work establishes an atlas of the human C2 DRG and identifies altered gene expression patterns associated with chronic neck pain. This work establishes a foundation for the exploration of painful disorders in humans affecting the cervical spine.

neuroscience↗

bioRxiv2025

Single-nuclei RNA Sequencing Reveals Distinct Transcriptomic Signatures of Rat Dorsal Root Ganglia in a Chronic Discogenic Low Back Pain Model

Chronic low back pain (LBP), often correlated with intervertebral disc degeneration, is a leading source of disability worldwide yet remains poorly understood. Current treatments often fail to provide sustained relief, highlighting the need to better understand the mechanisms driving discogenic LBP. During disc degeneration, the extracellular matrix degrades, allowing nociceptive nerve fibers to innervate previously aneural disc regions. Persistent mechanical and inflammatory stimulation of nociceptors can induce plastic changes within dorsal root ganglia (DRG) neurons, characterized by altered gene expression, enhanced excitability, and lowered activation thresholds. Although these transcriptional changes have been described in other pain states, including osteoarthritis, they remain underexplored in discogenic LBP. To address this gap, this study represents the first application of comprehensive single-nuclei RNA sequencing of DRG neurons in a rat model of chronic discogenic LBP. Eighteen distinct DRG subpopulations were identified and mapped to existing mouse and cross-species atlases revealing strong similarities in neuronal populations with the mouse. Differential expression analysis revealed increased expression of pain-associated genes, including Scn9a and Piezo2, and neuroinflammatory mediators such as Fstl1 and Ngfr, in LBP animals. Axial hypersensitivity, measured using grip strength, significantly correlated with increased expression of Scn9a, Fstl1, and Ngfr, which suggests their role in maintaining axial hypersensitivity in this model. These findings establish a relationship between DRG transcriptomic changes and axial hypersensitivity in a discogenic LBP model, identifying potential molecular targets for non-opioid treatments and advancing understanding of discogenic LBP mechanisms.

neuroscience↗

bioRxiv2024

Molecular architecture of human dermal sleeping nociceptors

Human dermal sleeping nociceptors display ongoing activity in neuropathic pain, affecting 10% of the population. Despite advances in rodents, a molecular marker for these mechano-insensitive C-fibers (CMis) in human skin remains elusive, preventing targeted therapy. In this translational Patch-seq study, we combine single-cell transcriptomics following electrophysiological characterization with single-nucleus and spatial transcriptomics from pigs and humans. We functionally identified CMis in pig sensory neurons with patch-clamp using adapted protocols from human microneurography. We identified oncostatin-M-receptor (OSMR) and somatostatin (SST) as marker genes for CMis. Following dermal injection in healthy human volunteers, oncostatin-M, the ligand of OSMR, exclusively modulates CMis. We identified the entire molecular architecture of human dermal sleeping nociceptors, providing new therapeutic targets and the basis for a mechanistic understanding of neuropathic pain. One Sentence SummaryWe identify the molecular architecture and specifically OSMR and SST as molecular markers for human dermal sleeping nociceptors, key players in the generation of neuropathic pain. Short versionIn this Patch-seq study, we identify OSMR and SST as molecular markers for human dermal sleeping nociceptors, key players in the generation of neuropathic pain.

neuroscience↗

bioRxiv2024

Lateralized nodose ganglia gene expression implicates cholecystokinin receptors in interoceptive reward signaling

The vagus nerves are important carriers of sensory information from the viscera to the brain. Emerging evidence suggests that sensory signaling through the right, but not the left, vagus nerve evokes striatal dopamine release and reinforces appetitive behaviors. However, the extent to which differential gene expression within vagal sensory neurons may underlie this asymmetric reward-related signaling is unknown. Here, we use single-nucleus RNA sequencing, in situ hybridization, and calcium imaging to identify a single cluster of neurons, defined by co-expression of Chrna3 (nicotinic acetylcholine receptor subunit 3) and Cckar (cholecystokinin 1 receptor), that is preferentially expressed in the right nodose ganglia of rats and mice. This neuronal population also expresses several genes implicated in digestive signaling, including Glp1r and Sctr, consistent with a gut-innervating subtype. Our results suggest that right-biased expression of this unique chemosensing vagal cell type may contribute to asymmetric encoding of interoceptive rewards by the vagus nerves.

neuroscience↗

bioRxiv2024

Single cell transcriptional analysis of human adenoids identifies molecular features of airway microfold cells

The nasal, oropharyngeal, and bronchial mucosa are primary contact points for airborne pathogens like Mycobacterium tuberculosis (Mtb), SARS-CoV-2, and influenza virus. While mucosal surfaces can function as both entry points and barriers to infection, mucosa-associated lymphoid tissues (MALT) facilitate early immune responses to mucosal antigens. MALT contains a variety of specialized epithelial cells, including a rare cell type called a microfold cell (M cell) that functions to transport apical antigens to basolateral antigen-presenting cells, a crucial step in the initiation of mucosal immunity. M cells have been extensively characterized in the gastrointestinal (GI) tract in murine and human models. However, the precise development and functions of human airway M cells is unknown. Here, using single-nucleus RNA sequencing (snRNA-seq), we generated an atlas of cells from the human adenoid and identified 16 unique cell types representing basal, club, hillock, and hematopoietic lineages, defined their developmental trajectories, and determined cell-cell relationships. Using trajectory analysis, we found that human airway M cells develop from progenitor club cells and express a gene signature distinct from intestinal M cells. Surprisingly, we also identified a heretofore unknown epithelial cell type demonstrating a robust interferon-stimulated gene signature. Our analysis of human adenoid cells enhances our understanding of mucosal immune responses and the role of M cells in airway immunity. This work also provides a resource for understanding early interactions of pathogens with airway mucosa and a platform for development of mucosal vaccines.

immunology↗

bioRxiv2024

Investigation of cellular and molecular changes linked with neuropathic pain in healthy and injured human trigeminal nerves

Injuries to the trigeminal nerve, responsible for sensory innervation to the face, may occur during routine dental procedures, resulting in the formation of a neuroma accompanied by loss of sensation and/or symptoms of pain. In order to gain insight into the molecular mechanisms underpinning the sensory changes, single nuclei RNA sequencing and spatial transcriptomics were employed to profile the transcriptional landscape at single cell resolution of human trigeminal nerves and neuromas. Cellular and transcriptional changes were identified that correlated with the presence of pain, including an expansion of endothelial cells with a pro-inflammatory phenotype and over-expression of HLA-A, CXCL2 and CXCL8. Interactome analysis highlighted signalling changes linked with the presence of pain. HLA-A protein expression was confirmed in neuromas and positively correlated with symptoms of pain. The atlas generated represents a valuable resource for pain research, highlighting the role of inflammation, endothelial cell dysfunction and chemokine signalling in neuropathic pain.

neuroscience↗

bioRxiv2024

Transcriptomic and histological characterization of telocytes in the human dorsal root ganglion

Telocytes are interstitial cells with long processes that cover distances in tissues and likely coordinate interacts with other cell types. Though present in central and peripheral neuronal tissues, their role remains unclear. Dorsal root ganglia (DRG) house pseudounipolar afferent neurons responsible for signals such as temperature, proprioception and nociception. This study aimed to investigate the presence and function of telocytes in human DRG by investigating their transcriptional profile, location and ultrastructure. Sequencing data revealed CD34 and PDGFRA expressing cells comprise roughly 1.5-3% of DRG cells. Combined expression of CD34 and PDGFRA is a putative marker gene set for telocytes. Further analysis identified nine subclusters with enriched cluster-specific genes. KEGG and GO pathway analysis suggested vascular, immune and connective tissue associated putative telocyte subtypes. Over 3000 potential receptor-ligand interactions between sensory neurons and these CD34 and PDGFRA expressing putative telocytes were identified using a ligand-receptors interactome platform. Immunohisto-chemistry showed CD34+ telocytes in the endoneural space of DRGs, next to neuron-satellite complexes, in perivascular spaces and in the endoneural space between nerve fibre bundles, consistent with pathway analysis. Transmission electron microscopy (TEM) confirmed their location identifying characteristic elongated nucleus, long and thin telopods containing vesicles, surrounded by a basal lamina. This is the first study that provides gene expression analysis of telocytes in complex human tissue such as the DRG, highlighting functional differences based on tissue location with no significant ultrastructural variation. Key pointsO_LIuman DRGs contain CD34/PDGFRA+ putative telocytes that can be subgrouped in nine clusters based on gene expression C_LIO_LIThe DRGs contain CD34+ telocytes in close proximity to neuron-satellite complexes, blood vessels and nerve fibre bundles. C_LIO_LIThe basic features of telocytes with elongated nuclei and thin telopods do not differ between locations. C_LI

neuroscience↗

bioRxiv2024

Nageotte nodules in human DRG reveal neurodegeneration in painful diabetic neuropathy

Diabetic neuropathy is frequently accompanied by pain and loss of sensation attributed to axonal dieback. We recovered dorsal root ganglia (DRGs) from 90 organ donors, 19 of whom had medical indices for diabetic painful neuropathy (DPN). Nageotte nodules, dead sensory neurons engulfed by non-neuronal cells, were abundant in DPN DRGs and accounted for 25% of all neurons. Peripherin-and Nav1.7-positive dystrophic axons invaded Nageotte nodules, forming small neuroma-like structures. Using histology and spatial sequencing, we demonstrate that Nageotte nodules are mainly composed of satellite glia and non-myelinating Schwann cells that express SPP1 and are intertwined with sprouting sensory axons originating from neighboring neurons. Our findings solve a 100-year mystery of the nature of Nageotte nodules linking these pathological structures to pain and sensory loss in DPN.

neuroscience↗