RESUMEN

The in vivo three-dimensional genomic architecture of adult mature neurons at homeostasis and after medically relevant perturbations such as axonal injury remains elusive. Here, we address this knowledge gap by mapping the three-dimensional chromatin architecture and gene expression program at homeostasis and after sciatic nerve injury in wild-type and cohesin-deficient mouse sensory dorsal root ganglia neurons via combinatorial Hi-C, promoter-capture Hi-C, CUT&Tag for H3K27ac and RNA-seq. We find that genes involved in axonal regeneration form long-range, complex chromatin loops, and that cohesin is required for the full induction of the regenerative transcriptional program. Importantly, loss of cohesin results in disruption of chromatin architecture and severely impaired nerve regeneration. Complex enhancer-promoter loops are also enriched in the human fetal cortical plate, where the axonal growth potential is highest, and are lost in mature adult neurons. Together, these data provide an original three-dimensional chromatin map of adult sensory neurons in vivo and demonstrate a role for cohesin-dependent long-range promoter interactions in nerve regeneration.

Asunto(s)

Axones , Cromatina , Cohesinas , Regeneración Nerviosa , Regiones Promotoras Genéticas , Células Receptoras Sensoriales , Animales , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/fisiología , Ratones , Regiones Promotoras Genéticas/genética , Cromatina/metabolismo , Regeneración Nerviosa/genética , Regeneración Nerviosa/fisiología , Axones/metabolismo , Axones/fisiología , Humanos , Proteínas Cromosómicas no Histona/metabolismo , Proteínas Cromosómicas no Histona/genética , Elementos de Facilitación Genéticos/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Ganglios Espinales/metabolismo , Ganglios Espinales/citología , Nervio Ciático/metabolismo

RESUMEN

Carbapenem-resistant Klebsiella pneumoniae (CRKP) causes Gram-negative lung infections and fatal pneumonic sepsis for which limited therapeutic options are available. The lungs are densely innervated by nociceptor sensory neurons that mediate breathing, cough, and bronchoconstriction. The role of nociceptors in defense against Gram-negative lung pathogens is unknown. Here, we found that lung-innervating nociceptors promote CRKP pneumonia and pneumonic sepsis. Ablation of nociceptors in mice increased lung CRKP clearance, suppressed trans-alveolar dissemination of CRKP, and protected mice from hypothermia and death. Furthermore, ablation of nociceptors enhanced the recruitment of neutrophils and Ly6Chi monocytes and cytokine induction. Depletion of Ly6Chi monocytes, but not of neutrophils, abrogated lung and extrapulmonary CRKP clearance in ablated mice, suggesting that Ly6Chi monocytes are a critical cellular population to regulate pneumonic sepsis. Further, neuropeptide calcitonin gene-related peptide suppressed the induction of reactive oxygen species in Ly6Chi monocytes and their CRKP-killing abilities. Targeting nociceptor signaling could be a therapeutic approach for treating multidrug-resistant Gram-negative infection and pneumonic sepsis.

Asunto(s)

Péptido Relacionado con Gen de Calcitonina , Carbapenémicos , Infecciones por Klebsiella , Klebsiella pneumoniae , Pulmón , Nociceptores , Sepsis , Animales , Klebsiella pneumoniae/fisiología , Ratones , Infecciones por Klebsiella/microbiología , Sepsis/metabolismo , Sepsis/microbiología , Pulmón/microbiología , Pulmón/metabolismo , Carbapenémicos/farmacología , Péptido Relacionado con Gen de Calcitonina/metabolismo , Nociceptores/metabolismo , Monocitos/metabolismo , Células Receptoras Sensoriales/metabolismo , Neutrófilos/metabolismo , Modelos Animales de Enfermedad , Antígenos Ly/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Neumonía Bacteriana/microbiología , Neumonía Bacteriana/metabolismo , Neumonía Bacteriana/patología , Ratones Endogámicos C57BL

RESUMEN

Increasing evidences demonstrate the role of sensory innervation in bone metabolism, remodeling and repair, however neurovascular coupling in bone is rarely studied. Using microfluidic devices as an indirect co-culture model to mimic in vitro the physiological scenario of innervation, our group demonstrated that sensory neurons (SNs) were able to regulate the extracellular matrix remodeling by endothelial cells (ECs), in particular through sensory neuropeptides, i.e. calcitonin gene-related peptide (CGRP) and substance P (SP). Nonetheless, still little is known about the cell signaling pathways and mechanism of action in neurovascular coupling. Here, in order to characterize the communication between SNs and ECs at molecular level, we evaluated the effect of SNs and the neuropeptides CGRP and SP on ECs. We focused on different pathways known to play a role on endothelial functions: calcium signaling, p38 and Erk1/2; the control of signal propagation through Cx43; and endothelial functions through the production of nitric oxide (NO). The effect of SNs was evaluated on ECs Ca2+ influx, the expression of Cx43, endothelial nitric oxide synthase (eNOS) and nitric oxide (NO) production, p38, ERK1/2 as well as their phosphorylated forms. In addition, the role of CGRP and SP were either analyzed using respective antagonists in the co-culture model, or by adding directly on the ECs monocultures. We show that capsaicin-stimulated SNs induce increased Ca2+ influx in ECs. SNs stimulate the increase of NO production in ECs, probably involving a decrease in the inhibitory eNOS T495 phosphorylation site. The neuropeptide CGRP, produced by SNs, seems to be one of the mediators of this effect in ECs since NO production is decreased in the presence of CGRP antagonist in the co-culture of ECs and SNs, and increased when ECs are stimulated with synthetic CGRP. Taken together, our results suggest that SNs play an important role in the control of the endothelial cell functions through CGRP production and NO signaling pathway.

Asunto(s)

Péptido Relacionado con Gen de Calcitonina , Células Endoteliales , Óxido Nítrico , Células Receptoras Sensoriales , Transducción de Señal , Sustancia P , Péptido Relacionado con Gen de Calcitonina/metabolismo , Péptido Relacionado con Gen de Calcitonina/farmacología , Sustancia P/farmacología , Sustancia P/metabolismo , Transducción de Señal/fisiología , Transducción de Señal/efectos de los fármacos , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Células Receptoras Sensoriales/efectos de los fármacos , Células Receptoras Sensoriales/metabolismo , Animales , Óxido Nítrico/metabolismo , Técnicas de Cocultivo , Comunicación Celular/fisiología , Comunicación Celular/efectos de los fármacos , Óxido Nítrico Sintasa de Tipo III/metabolismo , Células Cultivadas , Humanos , Ratas

RESUMEN

Although the role of peripheral nerves in cancer progression has been appreciated, little is known regarding cancer/sensory nerve crosstalk and its contribution to bone metastasis and associated pain. In this study, we revealed that the cancer/sensory nerve crosstalk plays a crucial role in bone metastatic progression. We found that (i) periosteal sensory nerves expressing calcitonin gene-related peptide (CGRP) are enriched in mice with bone metastasis; (ii) cancer patients with bone metastasis have elevated CGRP serum levels; (iii) bone metastatic patient tumor samples express elevated calcitonin receptor-like receptor (CRLR, a CGRP receptor component); (iv) higher CRLR levels in cancer patients are negatively correlated with recurrence-free survival; (v) CGRP induces cancer cell proliferation through the CRLR/p38/HSP27 pathway; and (vi) blocking sensory neuron-derived CGRP reduces cancer cell proliferation in vitro and bone metastatic progression in vivo. This suggests that CGRP-expressing sensory nerves are involved in bone metastatic progression and that the CGRP/CRLR axis may serve as a potential therapeutic target for bone metastasis.

Asunto(s)

Neoplasias Óseas , Péptido Relacionado con Gen de Calcitonina , Proliferación Celular , Progresión de la Enfermedad , Células Receptoras Sensoriales , Animales , Neoplasias Óseas/secundario , Neoplasias Óseas/metabolismo , Humanos , Ratones , Péptido Relacionado con Gen de Calcitonina/metabolismo , Células Receptoras Sensoriales/metabolismo , Línea Celular Tumoral , Proteína Similar al Receptor de Calcitonina/metabolismo , Proteína Similar al Receptor de Calcitonina/genética , Femenino , Masculino , Transducción de Señal

RESUMEN

Mutations in the presenilin (PS) genes are a predominant cause of familial Alzheimer's disease (fAD). An ortholog of PS in the genetic model organism Caenorhabditis elegans (C. elegans) is sel-12. Mutations in the presenilin genes are commonly thought to lead to fAD by upregulating the expression of amyloid beta (Aß), however this hypothesis has been challenged by recent evidence. As C. elegans lack amyloid beta (Aß), the goal of this work was to examine Aß-independent effects of mutations in sel-12 and PS1/PS2 on behaviour and sensory neuron morphology across the lifespan in a C. elegans model. Olfactory chemotaxis experiments were conducted on sel-12(ok2078) loss-of-function mutant worms. Adult sel-12 mutant worms showed significantly lower levels of chemotaxis to odorants compared to wild-type worms throughout their lifespan, and this deficit increased with age. The chemotaxis phenotype in sel-12 mutant worms is rescued by transgenic over-expression of human wild-type PS1, but not the classic fAD-associated variant PS1C410Y, when expression was driven by either the endogenous sel-12 promoter (Psel-12), a pan-neuronal promoter (Primb-1), or by a promoter whose primary expression was in the sensory neurons responsible for the chemotaxis behavior (Psra-6, Podr-10). The behavioural phenotype was also rescued by over-expressing an atypical fAD-linked mutation in PS1 (PS1ΔS169) that has been reported to leave the Notch pathway intact. An examination of the morphology of polymodal nociceptive (ASH) neurons responsible for the chemotaxis behavior also showed increased neurodegeneration over time in sel-12 mutant worms that could be rescued by the same transgenes that rescued the behaviour, demonstrating a parallel with the observed behavioral deficits. Thus, we report an Aß-independent neurodegeneration in C. elegans that was rescued by cell specific over-expression of wild-type human presenilin.

Asunto(s)

Enfermedad de Alzheimer , Péptidos beta-Amiloides , Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Mutación , Presenilina-1 , Animales , Humanos , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/metabolismo , Animales Modificados Genéticamente , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Quimiotaxis/genética , Modelos Animales de Enfermedad , Presenilina-1/genética , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/patología

RESUMEN

Photobiomodulation therapy (PBMT) is a form of treatment commonly used for routine clinical applications, such as wound healing of the skin and reduction of inflammation. Additionally, PBMT has been explored for its potential in pain relief. In this work, we investigated the effect of PBMT on ion content within the 50B11 sensory neurons cell line in vitro using X-Ray fluorescence (XRF) and atomic force microscope (AFM) analysis. Two irradiation protocols were selected utilizing near-infrared laser lights at 800 and 970 nm, with cell fixation immediately following irradiation. Results showed a decrease in Calcium content after irradiation with both protocols, and with lidocaine, used as an analgesic control. Furthermore, a reduction in Potassium content was observed, particularly evident when normalized to cellular volume. These findings provide valuable insights into the molecular impact of PBMT within 50B11 sensory neurons under normal conditions. Such understanding may contribute to the wider adoption of PBMT as a therapeutic approach.

Asunto(s)

Calcio , Rayos Infrarrojos , Terapia por Luz de Baja Intensidad , Células Receptoras Sensoriales , Animales , Células Receptoras Sensoriales/efectos de la radiación , Células Receptoras Sensoriales/metabolismo , Calcio/metabolismo , Ratones , Línea Celular , Espectrometría por Rayos X , Microscopía de Fuerza Atómica , Potasio/metabolismo , Potasio/química , Lidocaína/farmacología

RESUMEN

Epithelial damage leads to early reactive oxygen species (ROS) signaling, which regulates sensory neuron regeneration and tissue repair. How the initial type of tissue injury influences early damage signaling and regenerative growth of sensory axons remains unclear. Previously we reported that thermal injury triggers distinct early tissue responses in larval zebrafish. Here, we found that thermal but not mechanical injury impairs sensory axon regeneration and function. Real-time imaging revealed an immediate tissue response to thermal injury characterized by the rapid Arp2/3-dependent migration of keratinocytes, which was associated with tissue scale ROS production and sustained sensory axon damage. Isotonic treatment was sufficient to limit keratinocyte movement, spatially restrict ROS production, and rescue sensory neuron function. These results suggest that early keratinocyte dynamics regulate the spatial and temporal pattern of long-term signaling in the wound microenvironment during tissue repair.

Asunto(s)

Movimiento Celular , Oxidación-Reducción , Especies Reactivas de Oxígeno , Células Receptoras Sensoriales , Transducción de Señal , Pez Cebra , Animales , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/fisiología , Especies Reactivas de Oxígeno/metabolismo , Queratinocitos/metabolismo , Queratinocitos/fisiología , Células Epiteliales/metabolismo , Regeneración Nerviosa , Larva

RESUMEN

Neurological symptoms associated with COVID-19, acute and long term, suggest SARS-CoV-2 affects both the peripheral and central nervous systems (PNS/CNS). Although studies have shown olfactory and hematogenous invasion into the CNS, coinciding with neuroinflammation, little attention has been paid to susceptibility of the PNS to infection or to its contribution to CNS invasion. Here we show that sensory and autonomic neurons in the PNS are susceptible to productive infection with SARS-CoV-2 and outline physiological and molecular mechanisms mediating neuroinvasion. Our infection of K18-hACE2 mice, wild-type mice, and golden Syrian hamsters, as well as primary peripheral sensory and autonomic neuronal cultures, show viral RNA, proteins, and infectious virus in PNS neurons, satellite glial cells, and functionally connected CNS tissues. Additionally, we demonstrate, in vitro, that neuropilin-1 facilitates SARS-CoV-2 neuronal entry. SARS-CoV-2 rapidly invades the PNS prior to viremia, establishes a productive infection in peripheral neurons, and results in sensory symptoms often reported by COVID-19 patients.

Asunto(s)

COVID-19 , Neuropilina-1 , SARS-CoV-2 , Animales , SARS-CoV-2/fisiología , SARS-CoV-2/patogenicidad , COVID-19/virología , COVID-19/patología , COVID-19/metabolismo , Ratones , Neuropilina-1/metabolismo , Neuropilina-1/genética , Viremia/virología , Sistema Nervioso Central/virología , Sistema Nervioso Central/patología , Sistema Nervioso Central/metabolismo , Células Receptoras Sensoriales/virología , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/patología , Mesocricetus , Humanos , Enzima Convertidora de Angiotensina 2/metabolismo , Ratones Endogámicos C57BL , Internalización del Virus , Masculino

RESUMEN

Over half of spinal cord injury (SCI) patients develop opioid-resistant chronic neuropathic pain. Safer alternatives to opioids for treatment of neuropathic pain are gabapentinoids (e.g., pregabalin and gabapentin). Clinically, gabapentinoids appear to amplify opioid effects, increasing analgesia and overdose-related adverse outcomes, but in vitro proof of this amplification and its mechanism are lacking. We previously showed that after SCI, sensitivity to opioids is reduced by fourfold to sixfold in rat sensory neurons. Here, we demonstrate that after injury, gabapentinoids restore normal sensitivity of opioid inhibition of cyclic AMP (cAMP) generation, while reducing nociceptor hyperexcitability by inhibiting voltage-gated calcium channels (VGCCs). Increasing intracellular Ca2+ or activation of L-type VGCCs (L-VGCCs) suffices to mimic SCI effects on opioid sensitivity, in a manner dependent on the activity of the Raf1 proto-oncogene, serine/threonine-protein kinase C-Raf, but independent of neuronal depolarization. Together, our results provide a mechanism for potentiation of opioid effects by gabapentinoids after injury, via reduction of calcium influx through L-VGCCs, and suggest that other inhibitors targeting these channels may similarly enhance opioid treatment of neuropathic pain.

Asunto(s)

Analgésicos Opioides , AMP Cíclico , Gabapentina , Neuralgia , Transducción de Señal , Traumatismos de la Médula Espinal , Animales , Neuralgia/tratamiento farmacológico , Neuralgia/metabolismo , AMP Cíclico/metabolismo , Ratas , Traumatismos de la Médula Espinal/tratamiento farmacológico , Traumatismos de la Médula Espinal/metabolismo , Analgésicos Opioides/farmacología , Gabapentina/farmacología , Transducción de Señal/efectos de los fármacos , Ratas Sprague-Dawley , Masculino , Canales de Calcio Tipo L/metabolismo , Calcio/metabolismo , Pregabalina/farmacología , Pregabalina/uso terapéutico , Sinergismo Farmacológico , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/efectos de los fármacos

RESUMEN

Sensory axons projecting to the central nervous system are organized into topographic maps that represent the locations of sensory stimuli. In some sensory systems, even adjacent sensory axons are arranged topographically, forming "fine-scale" topographic maps. Although several broad molecular gradients are known to instruct coarse topography, we know little about the molecular signaling that regulates fine-scale topography at the level of two adjacent axons. Here, we provide evidence that transsynaptic bone morphogenetic protein (BMP) signaling mediates local interneuronal communication to regulate fine-scale topography in the nociceptive system of Drosophila larvae. We first show that the topographic separation of the axon terminals of adjacent nociceptors requires their common postsynaptic target, the A08n neurons. This phenotype is recapitulated by knockdown of the BMP ligand, Decapentaplegic (Dpp), in these neurons. In addition, removing the Type 2 BMP receptors or their effector (Mad transcription factor) in single nociceptors impairs the fine-scale topography, suggesting the contribution of BMP signaling originated from A08n. This signaling is likely mediated by phospho-Mad in the presynaptic terminals of nociceptors to ensure local interneuronal communication. Finally, reducing Dpp levels in A08n reduces the nociceptor-A08n synaptic contacts. Our data support that transsynaptic BMP signaling establishes the fine-scale topography by facilitating the formation of topographically correct synapses. Local BMP signaling for synapse formation may be a developmental strategy that independently regulates neighboring axon terminals for fine-scale topography.

Asunto(s)

Proteínas Morfogenéticas Óseas , Proteínas de Drosophila , Células Receptoras Sensoriales , Transducción de Señal , Animales , Proteínas de Drosophila/metabolismo , Proteínas Morfogenéticas Óseas/metabolismo , Transducción de Señal/fisiología , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/fisiología , Drosophila , Larva , Nociceptores/metabolismo , Nociceptores/fisiología , Animales Modificados Genéticamente , Sinapsis/metabolismo , Sinapsis/fisiología , Terminales Presinápticos/metabolismo , Terminales Presinápticos/fisiología , Proteínas de Unión al ADN , Factores de Transcripción

RESUMEN

The relationship between transcription and protein expression is complex. We identified polysome-associated RNA transcripts in the somata and central terminals of mouse sensory neurons in control, painful (plus nerve growth factor), and pain-free conditions (Nav1.7-null mice). The majority (98%) of translated transcripts are shared between male and female mice in both the somata and terminals. Some transcripts are highly enriched in the somata or terminals. Changes in the translatome in painful and pain-free conditions include novel and known regulators of pain pathways. Antisense knockdown of selected somatic and terminal polysome-associated transcripts that correlate with pain states diminished pain behavior. Terminal-enriched transcripts included those encoding synaptic proteins (e.g., synaptotagmin), non-coding RNAs, transcription factors (e.g., Znf431), proteins associated with transsynaptic trafficking (HoxC9), GABA-generating enzymes (Gad1 and Gad2), and neuropeptides (Penk). Thus, central terminal translation may well be a significant regulatory locus for peripheral input from sensory neurons.

Asunto(s)

Dolor , Células Receptoras Sensoriales , Animales , Células Receptoras Sensoriales/metabolismo , Ratones , Masculino , Femenino , Dolor/metabolismo , Biosíntesis de Proteínas , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Canal de Sodio Activado por Voltaje NAV1.7/genética , Glutamato Descarboxilasa/metabolismo , Glutamato Descarboxilasa/genética , Polirribosomas/metabolismo , Ratones Endogámicos C57BL , Ganglios Espinales/metabolismo

RESUMEN

The development of noninvasive approaches to precisely control neural activity in mammals is highly desirable. Here, we used the ion channel transient receptor potential ankyrin-repeat 1 (TRPA1) as a proof of principle, demonstrating remote near-infrared (NIR) activation of endogenous neuronal channels in mice through an engineered nanoagonist. This achievement enables specific neurostimulation in nongenetically modified mice. Initially, target-based screening identified flavins as photopharmacological agonists, allowing for the photoactivation of TRPA1 in sensory neurons upon ultraviolet A/blue light illumination. Subsequently, upconversion nanoparticles (UCNPs) were customized with an emission spectrum aligned to flavin absorption and conjugated with flavin adenine dinucleotide, creating a nanoagonist capable of NIR activation of TRPA1. Following the intrathecal injection of the nanoagonist, noninvasive NIR stimulation allows precise bidirectional control of nociception in mice through remote activation of spinal TRPA1. This study demonstrates a noninvasive NIR neurostimulation method with the potential for adaptation to various endogenous ion channels and neural processes by combining photochemical toolboxes with customized UCNPs.

Asunto(s)

Rayos Infrarrojos , Nanopartículas , Canal Catiónico TRPA1 , Animales , Canal Catiónico TRPA1/metabolismo , Canal Catiónico TRPA1/agonistas , Ratones , Nanopartículas/química , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/fisiología , Células Receptoras Sensoriales/efectos de los fármacos , Canales Iónicos/metabolismo , Nocicepción/efectos de los fármacos

RESUMEN

Tumour innervation is associated with worse patient outcomes in multiple cancers1,2, which suggests that it may regulate metastasis. Here we observed that highly metastatic mouse mammary tumours acquired more innervation than did less-metastatic tumours. This enhanced innervation was driven by expression of the axon-guidance molecule SLIT2 in tumour vasculature. Breast cancer cells induced spontaneous calcium activity in sensory neurons and elicited release of the neuropeptide substance P (SP). Using three-dimensional co-cultures and in vivo models, we found that neuronal SP promoted breast tumour growth, invasion and metastasis. Moreover, patient tumours with elevated SP exhibited enhanced lymph node metastatic spread. SP acted on tumoral tachykinin receptors (TACR1) to drive death of a small population of TACR1high cancer cells. Single-stranded RNAs (ssRNAs) released from dying cells acted on neighbouring tumoural Toll-like receptor 7 (TLR7) to non-canonically activate a prometastatic gene expression program. This SP- and ssRNA-induced Tlr7 gene expression signature was associated with reduced breast cancer survival outcomes. Therapeutic targeting of this neuro-cancer axis with the TACR1 antagonist aprepitant, an approved anti-nausea drug, suppressed breast cancer growth and metastasis in multiple models. Our findings reveal that tumour-induced hyperactivation of sensory neurons regulates multiple aspects of metastatic progression in breast cancer through a therapeutically targetable neuropeptide/extracellular ssRNA sensing axis.

Asunto(s)

Neoplasias de la Mama , Metástasis de la Neoplasia , ARN , Células Receptoras Sensoriales , Sustancia P , Receptor Toll-Like 7 , Animales , Femenino , Humanos , Ratones , Neoplasias de la Mama/irrigación sanguínea , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Metástasis Linfática , Invasividad Neoplásica , Proteínas del Tejido Nervioso/metabolismo , ARN/metabolismo , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/efectos de los fármacos , Sustancia P/metabolismo , Análisis de Supervivencia , Receptor Toll-Like 7/metabolismo , Receptores de Neuroquinina-1/metabolismo

RESUMEN

Electrical excitability-the ability to fire and propagate action potentials-is a signature feature of neurons. How neurons become excitable during development and whether excitability is an intrinsic property of neurons remain unclear. Here, we demonstrate that Schwann cells, the most abundant glia in the peripheral nervous system, promote somatosensory neuron excitability during development. We find that Schwann cells secrete prostaglandin E2, which is necessary and sufficient to induce developing somatosensory neurons to express normal levels of genes required for neuronal function, including voltage-gated sodium channels, and to fire action potential trains. Inactivating this signaling pathway in Schwann cells impairs somatosensory neuron maturation, causing multimodal sensory defects that persist into adulthood. Collectively, our studies uncover a neurodevelopmental role for prostaglandin E2 distinct from its established role in inflammation, revealing a cell non-autonomous mechanism by which glia regulate neuronal excitability to enable the development of normal sensory functions.

Asunto(s)

Potenciales de Acción , Dinoprostona , Células de Schwann , Células Receptoras Sensoriales , Animales , Células de Schwann/metabolismo , Dinoprostona/metabolismo , Ratones , Células Receptoras Sensoriales/metabolismo , Transducción de Señal

RESUMEN

Neuropathic pain is characterised by periodic or continuous hyperalgesia, numbness, or allodynia, and results from insults to the somatosensory nervous system. Peripheral nerve injury induces transcriptional reprogramming in peripheral sensory neurons, contributing to increased spinal nociceptive input and the development of neuropathic pain. Effective treatment for neuropathic pain remains an unmet medical need as current therapeutics offer limited effectiveness and have undesirable effects. Understanding transcriptional changes in peripheral nerve injury-induced neuropathy might offer a path for novel analgesics. Our literature search identified 65 papers exploring transcriptomic changes post-peripheral nerve injury, many of which were conducted in animal models. We scrutinize their transcriptional changes data and conduct gene ontology enrichment analysis to reveal their common functional profile. Focusing on genes involved in 'sensory perception of pain' (GO:0019233), we identified transcriptional changes for different ion channels, receptors, and neurotransmitters, shedding light on its role in nociception. Examining peripheral sensory neurons subtype-specific transcriptional reprograming and regeneration-associated genes, we delved into downstream regulation of hypersensitivity. Identifying the temporal program of transcription regulatory mechanisms might help develop better therapeutics to target them effectively and selectively, thus preventing the development of neuropathic pain without affecting other physiological functions.

Asunto(s)

Neuralgia , Traumatismos de los Nervios Periféricos , Animales , Traumatismos de los Nervios Periféricos/genética , Traumatismos de los Nervios Periféricos/metabolismo , Neuralgia/genética , Neuralgia/metabolismo , Humanos , Transcriptoma , Células Receptoras Sensoriales/metabolismo

RESUMEN

Interactions between the nervous system and the immune system play crucial roles in initiating and directing the type 2 immune response. Sensory neurons can initiate innate and adaptive type 2 immunity through their ability to detect allergens and promote dendritic cell and mast cell responses. Neurons also indirectly promote type 2 inflammation through suppression of type 1 immune responses. Type 2 cytokines promote neuronal function by directly activating or sensitizing neurons. This positive neuroimmune feedback loop may not only enhance allergic inflammation but also promote the system-wide responses of aversion, anaphylaxis, and allergen polysensitization that are characteristic of allergic immunity.

Asunto(s)

Alérgenos , Hipersensibilidad , Neuroinmunomodulación , Humanos , Alérgenos/inmunología , Animales , Hipersensibilidad/inmunología , Citocinas/metabolismo , Citocinas/inmunología , Células Receptoras Sensoriales/inmunología , Células Receptoras Sensoriales/metabolismo , Mastocitos/inmunología

RESUMEN

Insulin has been shown to modulate neuronal processes through insulin receptors. The ion channels located on neurons may be important targets for insulin/insulin receptor signaling. Both insulin receptors and acid-sensing ion channels (ASICs) are expressed in dorsal root ganglia (DRG) neurons. However, it is still unclear whether there is an interaction between them. Therefore, the purpose of this investigation was to determine the effects of insulin on the functional activity of ASICs. A 5 min application of insulin rapidly enhanced acid-evoked ASIC currents in rat DRG neurons in a concentration-dependent manner. Insulin shifted the concentration-response plot for ASIC currents upward, with an increase of 46.2 ± 7.6% in the maximal current response. The insulin-induced increase in ASIC currents was eliminated by the insulin receptor antagonist GSK1838705, the tyrosine kinase inhibitor lavendustin A, and the phosphatidylinositol-3 kinase antagonist wortmannin. Moreover, insulin increased the number of acid-triggered action potentials by activating insulin receptors. Finally, local administration of insulin exacerbated the spontaneous nociceptive behaviors induced by intraplantar acid injection and the mechanical hyperalgesia induced by intramuscular acid injections through peripheral insulin receptors. These results suggested that insulin/insulin receptor signaling enhanced the functional activity of ASICs via tyrosine kinase and phosphatidylinositol-3 kinase pathways. Our findings revealed that ASICs were targets in primary sensory neurons for insulin receptor signaling, which may underlie insulin modulation of pain.

Asunto(s)

Canales Iónicos Sensibles al Ácido , Ganglios Espinales , Insulina , Receptor de Insulina , Células Receptoras Sensoriales , Animales , Canales Iónicos Sensibles al Ácido/metabolismo , Insulina/metabolismo , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/efectos de los fármacos , Ganglios Espinales/metabolismo , Ganglios Espinales/efectos de los fármacos , Ganglios Espinales/citología , Ratas , Receptor de Insulina/metabolismo , Masculino , Transducción de Señal/efectos de los fármacos , Potenciales de Acción/efectos de los fármacos , Ratas Sprague-Dawley , Hiperalgesia/metabolismo , Células Cultivadas

RESUMEN

We developed a rat dorsal root ganglion (DRG)-derived sensory nerve organotypic model by culturing DRG explants on an organoid culture device. With this method, a large number of organotypic cultures can be produced simultaneously with high reproducibility simply by seeding DRG explants derived from rat embryos. Unlike previous DRG explant models, this organotypic model consists of a ganglion and an axon bundle with myelinated A fibers, unmyelinated C fibers, and stereo-myelin-forming nodes of Ranvier. The model also exhibits Ca2+ signaling in cell bodies in response to application of chemical stimuli to nerve terminals. Further, axonal transection increases the activating transcription factor 3 mRNA level in ganglia. Axons and myelin are shown to regenerate 14 days following transection. Our sensory organotypic model enables analysis of neuronal excitability in response to pain stimuli and tracking of morphological changes in the axon bundle over weeks.

Asunto(s)

Axones , Ganglios Espinales , Sistemas Microfisiológicos , Animales , Ratas , Factor de Transcripción Activador 3 , Axones/fisiología , Axones/metabolismo , Señalización del Calcio , Ganglios Espinales/citología , Ganglios Espinales/metabolismo , Vaina de Mielina/fisiología , Vaina de Mielina/metabolismo , Organoides/metabolismo , Nervios Periféricos/metabolismo , Ratas Sprague-Dawley , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/fisiología

RESUMEN

Dental pulp stem cells (DPSCs) are responsible for maintaining pulp structure and function after pulp injury. DPSCs migrate directionally to the injury site before differentiating into odontoblast-like cells, which is a prerequisite and a determinant in pulp repair. Increasing evidence suggests that sensory neuron-stem cell crosstalk is critical for maintaining normal physiological functions, and sensory nerves influence stem cells mainly by neuropeptides. However, the role of sensory nerves on DPSC behaviors after pulp injury is largely unexplored. Here, we find that sensory nerves released significant amounts of calcitonin gene-related peptide (CGRP) near the injury site, acting directly on DPSCs via receptor activity modifying protein 1 (RAMP1) to promote collective migration of DPSCs to the injury site, and ultimately promoting pulp repair. Specifically, sensory denervation leads to poor pulp repair and ectopic mineralization, in parallel with that DPSCs failed to be recruited to the injury site. Furthermore, in vitro evidence shows that sensory nerve-deficient microenvironment suppressed DPSC migration prominently among all related behaviors. Mechanistically, the CGRP-Ramp1 axis between sensory neurons and DPSCs was screened by single-cell RNA-seq analysis and immunohistochemical studies confirmed that the expression of CGRP rather than Ramp1 increases substantially near the damaged site. We further demonstrated that CGRP released by sensory nerves binds the receptor Ramp1 on DPSCs to facilitate cell collective migration by an indirect co-culture system using conditioned medium from trigeminal neurons, CGRP recombinant protein and antagonists BIBN4096. The treatment with exogenous CGRP promoted the recruitment of DPSCs, and ultimately enhanced the quality of pulp repair. Targeting the sensory nerve could therefore provide a new strategy for stem cell-based pulp repair and regeneration.

Asunto(s)

Péptido Relacionado con Gen de Calcitonina , Movimiento Celular , Pulpa Dental , Proteína 1 Modificadora de la Actividad de Receptores , Células Receptoras Sensoriales , Células Madre , Pulpa Dental/citología , Pulpa Dental/metabolismo , Péptido Relacionado con Gen de Calcitonina/metabolismo , Péptido Relacionado con Gen de Calcitonina/genética , Proteína 1 Modificadora de la Actividad de Receptores/metabolismo , Proteína 1 Modificadora de la Actividad de Receptores/genética , Células Madre/metabolismo , Células Madre/citología , Animales , Humanos , Células Receptoras Sensoriales/metabolismo , Ratones , Masculino , Cicatrización de Heridas/fisiología , Diferenciación Celular , Transducción de Señal , Células Cultivadas , Ratas

RESUMEN

Rosacea patients show facial hypersensitivity to stimulus factors (such as heat and capsaicin); however, the underlying mechanism of this hyperresponsiveness remains poorly defined. Here, we show capsaicin stimulation in mice induces exacerbated rosacea-like dermatitis but has no apparent effect on normal skin. Nociceptor ablation substantially reduces the hyperresponsiveness of rosacea-like dermatitis. Subsequently, we find that γδ T cells express Ramp1, the receptor of the neuropeptide CGRP, and are in close contact with these nociceptors in the skin. γδ T cells are significantly increased in rosacea skin lesions and can be further recruited and activated by neuron-secreted CGRP. Rosacea-like dermatitis is reduced in T cell receptor δ-deficient (Tcrd-/-) mice, and the nociceptor-mediated aggravation of rosacea-like dermatitis is also reduced in these mice. In vitro experiments show that CGRP induces IL17A secretion from γδ T cells by regulating inflammation-related and metabolism-related pathways. Finally, rimegepant, a CGRP receptor antagonist, shows efficacy in the treatment of rosacea-like dermatitis. In conclusion, our findings demonstrate a neuron-CGRP-γδT cell axis that contributes to the hyperresponsiveness of rosacea, thereby showing that targeting CGRP is a potentially effective therapeutic strategy for rosacea.

Asunto(s)

Péptido Relacionado con Gen de Calcitonina , Capsaicina , Receptores de Antígenos de Linfocitos T gamma-delta , Rosácea , Células Receptoras Sensoriales , Animales , Rosácea/inmunología , Ratones , Péptido Relacionado con Gen de Calcitonina/metabolismo , Células Receptoras Sensoriales/metabolismo , Capsaicina/farmacología , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Receptores de Antígenos de Linfocitos T gamma-delta/genética , Piel/patología , Piel/inmunología , Piel/metabolismo , Interleucina-17/metabolismo , Interleucina-17/inmunología , Ratones Noqueados , Ratones Endogámicos C57BL , Dermatitis/inmunología , Dermatitis/metabolismo , Dermatitis/patología , Modelos Animales de Enfermedad , Masculino , Nociceptores/metabolismo , Linfocitos T/inmunología , Linfocitos T/metabolismo , Humanos , Receptores de Péptido Relacionado con el Gen de Calcitonina/metabolismo