scholarly journals Nuclear Factor κB-COX2 Pathway Activation in Non-myelinating Schwann Cells Is Necessary for the Maintenance of Neuropathic Pain in vivo

2022 ◽  
Vol 15 ◽  
Author(s):  
Alison Xiaoqiao Xie ◽  
Sarah Taves ◽  
Ken McCarthy
Keyword(s):  
Chronic Pain ◽  
Neuropathic Pain ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Glial Cells ◽  
Nuclear Factor Κb ◽  
Pain Behavior ◽  
Nuclear Factor ◽  
Nociceptive Neurons

Chronic neuropathic pain leads to long-term changes in the sensitivity of both peripheral and central nociceptive neurons. Glial fibrillary acidic protein (GFAP)-positive glial cells are closely associated with the nociceptive neurons including astrocytes in the central nervous system (CNS), satellite glial cells (SGCs) in the sensory ganglia, and non-myelinating Schwann cells (NMSCs) in the peripheral nerves. Central and peripheral GFAP-positive cells are involved in the maintenance of chronic pain through a host of inflammatory cytokines, many of which are under control of the transcription factor nuclear factor κB (NFκB) and the enzyme cyclooxygenase 2 (COX2). To test the hypothesis that inhibiting GFAP-positive glial signaling alleviates chronic pain, we used (1) a conditional knockout (cKO) mouse expressing Cre recombinase under the hGFAP promoter and a floxed COX2 gene to inactivate the COX2 gene specifically in GFAP-positive cells; and (2) a tet-Off tetracycline transactivator system to suppress NFκB activation in GFAP-positive cells. We found that neuropathic pain behavior following spared nerve injury (SNI) significantly decreased in COX2 cKO mice as well as in mice with decreased glial NFκB signaling. Additionally, experiments were performed to determine whether central or peripheral glial NFκB signaling contributes to the maintenance of chronic pain behavior following nerve injury. Oxytetracycline (Oxy), a blood-brain barrier impermeable analog of doxycycline was employed to restrict transgene expression to CNS glia only, leaving peripheral glial signaling intact. Signaling inactivation in central GFAP-positive glia alone failed to exhibit the same analgesic effects as previously observed in animals with both central and peripheral glial signaling inhibition. These data suggest that the NFκB-COX2 signaling pathway in NMSCs is necessary for the maintenance of neuropathic pain in vivo.

scholarly journals Spinal NGF Restores Opioid Sensitivity in Neuropathic Rats: Possible Role of NGF as a Regulator of CCK-Induced Anti-Opioid Effects

2000 ◽  
Vol 5 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Catherine M Cahill ◽  
Terence J Coderre
Keyword(s):  
Chronic Pain ◽  
Neuropathic Pain ◽  
Nerve Injury ◽  
Postnatal Period ◽  
Spontaneous Pain ◽  
Pain Mechanisms ◽  
Nociceptive Neurons ◽  
Nociceptive Transmission ◽  
Chronic Pain Conditions ◽  
Injury Models

The breadth of peripheral effects produced by nerve growth factor (NGF) in nociceptive processing has been well documented. However, less is known about the functional significance of central NGF in nociceptive transmission. The effect of NGF on the nervous system is dependent on the developmental stage. During the prenatal developmental period, NGF is critical for survival of nociceptors; in the postnatal period it regulates the expression of nociceptor phenotype, and in the adult it contributes to pain following an inflammatory insult. The implications for central NGF in the expression and regulation of spinal neuropeptides that are involved in pain mechanisms are reviewed. Knowledge has been gained by studies using peripheral nerve injury models that cause a deprivation of central NGF. These models also give rise to the development of pain syndromes, which encompass spontaneous pain, hyperalgesia and allodynia, routinely referred to as neuropathic pain. These models provide an approach for examining the contribution of central NGF to nociceptive transmission. Chronic pain emanating from a nerve injury is typically refractory to traditional analgesics such as opioids. Recent evidence suggests that supplementation of spinal NGF restores morphine-induced antinociception in an animal model of neuropathic pain. This effect appears to be mediated by alterations in spinal levels of cholecystokinin. The authors hypothesize that NGF is critical in maintaining neurochemical homeostasis in the spinal cord of nociceptive neurons, and that supplementation may be beneficial in restoring and/or maintaining opioid analgesia in chronic pain conditions resulting from traumatic nerve injury.

scholarly journals Lack of efficacy of a partial adenosine A1 receptor agonist in neuropathic pain models in mice

2021 ◽  
Author(s):  
Katharina Metzner ◽  
Tilman Gross ◽  
Annika Balzulat ◽  
Gesine Wack ◽  
Ruirui Lu ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Nerve Injury ◽  
Partial Agonist ◽  
Pharmacological Intervention ◽  
Spared Nerve Injury ◽  
Drg Neurons ◽  
Behavioral Experiments ◽  
Nociceptive Neurons ◽  
Electrophysiological Properties

AbstractPrevious studies suggest that adenosine A1 receptors (A1R) modulate the processing of pain. The aim of this study was to characterize the distribution of A1R in nociceptive tissues and to evaluate whether targeting A1R with the partial agonist capadenoson may reduce neuropathic pain in mice. The cellular distribution of A1R in dorsal root ganglia (DRG) and the spinal cord was analyzed using fluorescent in situ hybridization. In behavioral experiments, neuropathic pain was induced by spared nerve injury or intraperitoneal injection of paclitaxel, and tactile hypersensitivities were determined using a dynamic plantar aesthesiometer. Whole-cell patch-clamp recordings were performed to assess electrophysiological properties of dissociated DRG neurons. We found A1R to be expressed in populations of DRG neurons and dorsal horn neurons involved in the processing of pain. However, administration of capadenoson at established in vivo doses (0.03–1.0 mg/kg) did not alter mechanical hypersensitivity in the spared nerve injury and paclitaxel models of neuropathic pain, whereas the standard analgesic pregabalin significantly inhibited the pain behavior. Moreover, capadenoson failed to affect potassium currents in DRG neurons, in contrast to a full A1R agonist. Despite expression of A1R in nociceptive neurons, our data do not support the hypothesis that pharmacological intervention with partial A1R agonists might be a valuable approach for the treatment of neuropathic pain.

scholarly journals Satellite glial cells in sensory ganglia express functional transient receptor potential ankyrin 1 that is sensitized in neuropathic and inflammatory pain

2020 ◽  
Vol 16 ◽  
pp. 174480692092542 ◽  
Author(s):  
Seung Min Shin ◽  
Brandon Itson-Zoske ◽  
Yongsong Cai ◽  
Chensheng Qiu ◽  
Bin Pan ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Nerve Injury ◽  
Glial Cells ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Allyl Isothiocyanate ◽  
Sensory Ganglia ◽  
Satellite Glial Cells ◽  
Intracellular Ca ◽  
Transient Receptor

Transient receptor potential ankyrin 1 (TRPA1) is well documented as an important molecule in pain hypersensitivity following inflammation and nerve injury and in many other cellular biological processes. Here, we show that TRPA1 is expressed not only by sensory neurons of the dorsal root ganglia (DRG) but also in their adjacent satellite glial cells (SGCs), as well as nonmyelinating Schwann cells. TRPA1 immunoreactivity is also detected in various cutaneous structures of sensory neuronal terminals, including small and large caliber cutaneous sensory fibers and endings. The SGC-expressed TRPA1 is functional. Like DRG neurons, dissociated SGCs exhibit a robust response to the TRPA1-selective agonist allyl isothiocyanate (AITC) by an increase of intracellular Ca2+ concentration ([Ca2+]i). These responses are abolished by the TRPA1 antagonist HC030031 and are absent in SGCs and neurons from global TRPA1 null mice. SGCs and neurons harvested from DRG proximal to painful tissue inflammation induced by plantar injection of complete Freund’s adjuvant show greater AITC-evoked elevation of [Ca2+]i and slower recovery compared to sham controls. Similar TRPA1 sensitization occurs in both SGCs and neurons during neuropathic pain induced by spared nerve injury. Together, these results show that functional TRPA1 is expressed by sensory ganglia SGCs, and TRPA1 function in SGCs is enhanced after both peripheral inflammation and nerve injury, and suggest that TRPA1 in SGCs may contribute to inflammatory and neuropathic pain.

scholarly journals Periprosthetic Osteolysis: Mechanisms, Prevention and Treatment

2019 ◽  
Vol 8 (12) ◽  
pp. 2091 ◽  
Author(s):  
Stuart B. Goodman ◽  
Jiri Gallo
Keyword(s):  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Activator Protein 1 ◽  
Periprosthetic Osteolysis ◽  
Bone Implant ◽  
Joint Replacements ◽  
In Vivo Experiments ◽  
Mechanical Factors

Clinical studies, as well as in vitro and in vivo experiments have demonstrated that byproducts from joint replacements induce an inflammatory reaction that can result in periprosthetic osteolysis (PPOL) and aseptic loosening (AL). Particle-stimulated macrophages and other cells release cytokines, chemokines, and other pro-inflammatory substances that perpetuate chronic inflammation, induce osteoclastic bone resorption and suppress bone formation. Differentiation, maturation, activation, and survival of osteoclasts at the bone–implant interface are under the control of the receptor activator of nuclear factor kappa-Β ligand (RANKL)-dependent pathways, and the transcription factors like nuclear factor κB (NF-κB) and activator protein-1 (AP-1). Mechanical factors such as prosthetic micromotion and oscillations in fluid pressures also contribute to PPOL. The treatment for progressive PPOL is only surgical. In order to mitigate ongoing loss of host bone, a number of non-operative approaches have been proposed. However, except for the use of bisphosphonates in selected cases, none are evidence based. To date, the most successful and effective approach to preventing PPOL is usage of wear-resistant bearing couples in combination with advanced implant designs, reducing the load of metallic and polymer particles. These innovations have significantly decreased the revision rate due to AL and PPOL in the last decade.

scholarly journals Role of the immune system in neuropathic pain

2019 ◽  
Vol 20 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Marzia Malcangio
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Nervous System ◽  
Neuropathic Pain ◽  
Immune System ◽  
Peripheral Nerve ◽  
Dorsal Horn ◽  
Nerve Injury ◽  
Immune Cells ◽  
Peripheral Nerve Injury

AbstractBackgroundAcute pain is a warning mechanism that exists to prevent tissue damage, however pain can outlast its protective purpose and persist beyond injury, becoming chronic. Chronic Pain is maladaptive and needs addressing as available medicines are only partially effective and cause severe side effects. There are profound differences between acute and chronic pain. Dramatic changes occur in both peripheral and central pathways resulting in the pain system being sensitised, thereby leading to exaggerated responses to noxious stimuli (hyperalgesia) and responses to non-noxious stimuli (allodynia).Critical role for immune system cells in chronic painPreclinical models of neuropathic pain provide evidence for a critical mechanistic role for immune cells in the chronicity of pain. Importantly, human imaging studies are consistent with preclinical findings, with glial activation evident in the brain of patients experiencing chronic pain. Indeed, immune cells are no longer considered to be passive bystanders in the nervous system; a consensus is emerging that, through their communication with neurons, they can both propagate and maintain disease states, including neuropathic pain. The focus of this review is on the plastic changes that occur under neuropathic pain conditions at the site of nerve injury, the dorsal root ganglia (DRG) and the dorsal horn of the spinal cord. At these sites both endothelial damage and increased neuronal activity result in recruitment of monocytes/macrophages (peripherally) and activation of microglia (centrally), which release mediators that lead to sensitisation of neurons thereby enabling positive feedback that sustains chronic pain.Immune system reactions to peripheral nerve injuriesAt the site of peripheral nerve injury following chemotherapy treatment for cancer for example, the occurrence of endothelial activation results in recruitment of CX3C chemokine receptor 1 (CX3CR1)-expressing monocytes/macrophages, which sensitise nociceptive neurons through the release of reactive oxygen species (ROS) that activate transient receptor potential ankyrin 1 (TRPA1) channels to evoke a pain response. In the DRG, neuro-immune cross talk following peripheral nerve injury is accomplished through the release of extracellular vesicles by neurons, which are engulfed by nearby macrophages. These vesicles deliver several determinants including microRNAs (miRs), with the potential to afford long-term alterations in macrophages that impact pain mechanisms. On one hand the delivery of neuron-derived miR-21 to macrophages for example, polarises these cells towards a pro-inflammatory/pro-nociceptive phenotype; on the other hand, silencing miR-21 expression in sensory neurons prevents both development of neuropathic allodynia and recruitment of macrophages in the DRG.Immune system mechanisms in the central nervous systemIn the dorsal horn of the spinal cord, growing evidence over the last two decades has delineated signalling pathways that mediate neuron-microglia communication such as P2X4/BDNF/GABAA, P2X7/Cathepsin S/Fractalkine/CX3CR1, and CSF-1/CSF-1R/DAP12 pathway-dependent mechanisms.Conclusions and implicationsDefinition of the modalities by which neuron and immune cells communicate at different locations of the pain pathway under neuropathic pain states constitutes innovative biology that takes the pain field in a different direction and provides opportunities for novel approaches for the treatment of chronic pain.

In Vitro and in Vivo Nuclear Factor-κB Inhibitory Effects of the Cell-Penetrating Penetratin Peptide

2006 ◽  
Vol 69 (6) ◽  
pp. 2027-2036 ◽  
Author(s):  
Tamás Letoha ◽  
Erzsébet Kusz ◽  
Gábor Pápai ◽  
Annamária Szabolcs ◽  
József Kaszaki ◽  
...  
Keyword(s):  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Inhibitory Effects ◽  
Cell Penetrating

HCN2 ion channels: basic science opens up possibilities for therapeutic intervention in neuropathic pain

2016 ◽  
Vol 473 (18) ◽  
pp. 2717-2736 ◽  
Author(s):  
Christoforos Tsantoulas ◽  
Elizabeth R. Mooney ◽  
Peter A. McNaughton
Keyword(s):  
Chronic Pain ◽  
Neuropathic Pain ◽  
Ion Channels ◽  
Warning Signal ◽  
Sensory Nerves ◽  
Nociceptive Neurons ◽  
Pain Syndromes ◽  
Medical Need ◽  
Pathological Pain ◽  
Genetic Deletion

Nociception — the ability to detect painful stimuli — is an invaluable sense that warns against present or imminent damage. In patients with chronic pain, however, this warning signal persists in the absence of any genuine threat and affects all aspects of everyday life. Neuropathic pain, a form of chronic pain caused by damage to sensory nerves themselves, is dishearteningly refractory to drugs that may work in other types of pain and is a major unmet medical need begging for novel analgesics. Hyperpolarisation-activated cyclic nucleotide (HCN)-modulated ion channels are best known for their fundamental pacemaker role in the heart; here, we review data demonstrating that the HCN2 isoform acts in an analogous way as a ‘pacemaker for pain’, in that its activity in nociceptive neurons is critical for the maintenance of electrical activity and for the sensation of chronic pain in pathological pain states. Pharmacological block or genetic deletion of HCN2 in sensory neurons provides robust pain relief in a variety of animal models of inflammatory and neuropathic pain, without any effect on normal sensation of acute pain. We discuss the implications of these findings for our understanding of neuropathic pain pathogenesis, and we outline possible future opportunities for the development of efficacious and safe pharmacotherapies in a range of chronic pain syndromes.

Fucoidans from Cucumaria frondosa ameliorates renal interstitial fibrosis via inhibition of PI3K/Akt/NF-κB signaling pathway

2022 ◽  
Author(s):  
Zhuo-yue Song ◽  
Mengru Zhu ◽  
Jun Wu ◽  
Tian Yu ◽  
Yao Chen ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Signaling Pathway ◽  
Interstitial Fibrosis ◽  
Protein Kinase B ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Renal Interstitial Fibrosis ◽  
Cucumaria Frondosa

The effects of Cucumaria frondosa polysaccharides (CFP) on renal interstitial fibrosis via regulating phosphatidylinositol-3-hydroxykinase/protein kinase-B/Nuclear factor-κB (PI3K/AKT/NF-κB) signaling pathway were investigated in vivo and in vitro in this research. A...

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