scholarly journals Control of mechanical pain hypersensitivity through ligand-targeted photoablation of TrkB positive sensory neurons

2017 ◽  
Author(s):  
Rahul Dhandapani ◽  
Cynthia Mary Arokiaraj ◽  
Francisco J. Taberner ◽  
Paola Pacifico ◽  
Sruthi Raja ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Nerve Injury ◽  
Sensory Neurons ◽  
Mechanical Allodynia ◽  
List Type ◽  
Light Touch ◽  
Peripheral Neurons ◽  
Necessary And Sufficient ◽  
Peripheral Sensory

SummaryMechanical allodynia is a major symptom of neuropathic pain whereby innocuous touch evokes severe pain. Here we identify a population of peripheral sensory neurons expressing TrkB that are both necessary and sufficient for producing pain from light touch after nerve injury. Mice in which TrkB-Cre expressing neurons are ablated are less sensitive to the lightest touch under basal conditions, and fail to develop mechanical allodynia in a model of neuropathic pain. Moreover, selective optogenetic activation of these neurons after nerve injury evokes marked nociceptive behavior. Using a phototherapeutic approach based upon BDNF, the ligand for TrkB, we perform molecule-guided laser ablation of these neurons and achieve long-term retraction of TrkB positive neurons from the skin and pronounced reversal of mechanical allodynia across multiple types of neuropathic pain. Thus we identify the peripheral neurons which transmit pain from light touch and uncover a novel pharmacological strategy for its treatment.HighlightsTrkB+ neurons detect light touch under basal conditionsTrkB+ neurons convey mechanical allodynia in neuropathic pain statesA photosensitizing derivative of BDNF allows for photoablation of TrkB+ neuronsBDNF-guided photoablation reverses allodynia in multiple types of neuropathic pain

Importin α3 regulates chronic pain pathways in peripheral sensory neurons

Science ◽  
2020 ◽  
Vol 369 (6505) ◽  
pp. 842-846 ◽  
Author(s):  
Letizia Marvaldi ◽  
Nicolas Panayotis ◽  
Stefanie Alber ◽  
Shachar Y. Dagan ◽  
Nataliya Okladnikov ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Sensory Neurons ◽  
Nuclear Import ◽  
Nucleocytoplasmic Transport ◽  
Dominant Negative ◽  
Peripheral Neurons ◽  
Pain Pathways ◽  
Peripheral Sensory Neurons ◽  
Control Pain ◽  
Peripheral Sensory

How is neuropathic pain regulated in peripheral sensory neurons? Importins are key regulators of nucleocytoplasmic transport. In this study, we found that importin α3 (also known as karyopherin subunit alpha 4) can control pain responsiveness in peripheral sensory neurons in mice. Importin α3 knockout or sensory neuron–specific knockdown in mice reduced responsiveness to diverse noxious stimuli and increased tolerance to neuropathic pain. Importin α3–bound c-Fos and importin α3–deficient neurons were impaired in c-Fos nuclear import. Knockdown or dominant-negative inhibition of c-Fos or c-Jun in sensory neurons reduced neuropathic pain. In silico screens identified drugs that mimic importin α3 deficiency. These drugs attenuated neuropathic pain and reduced c-Fos nuclear localization. Thus, perturbing c-Fos nuclear import by importin α3 in peripheral neurons can promote analgesia.

Peripheral sensory neurons and non-neuronal cells express functional Piezo1 that is activated in peripheral nerve injury-induced neuropathic pain

2021 ◽  
Author(s):  
Seung Min Shin ◽  
Brandon Itson-Zoske ◽  
Fan Fan ◽  
Cheryl L. Stucky ◽  
Quinn H. Hogan ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Sensory Neurons ◽  
Peripheral Nerve Injury ◽  
Neuronal Cells ◽  
Satellite Glial Cells ◽  
Peripheral Sensory

AbstractHere, we present evidence showing Piezo1 expression in the primary sensory neurons (PSNs) and non-neuronal cells of rat peripheral nervous system. Using a knockdown/knockout validated antibody, we detected Piezo1 immunoreactivity (IR) in ∼80% of PSNs of rat dorsal root ganglia (DRG) with higher IR density in the small- and medium-sized neurons, and within axons extending to both central presynaptic terminals innervating to the spinal dorsal horn and peripheral cutaneous sensory terminals in the skin. Piezo-IR was clearly identified in DRG perineuronal glia, including satellite glial cells (SGCs) and non-myelinating Schwann cells; in sciatic nerve Schwann cells surrounding the axons and cutaneous afferent endings; and in skin epidermal Merkel cells and melanocytes. Neuronal and non-neuronal Piezo1 channels were functional, since various cells (dissociated PSNs and SGCs from DRGs, isolated Schwann cells, and primary human melanocytes) exhibited a robust response to Piezo1 agonist Yoda1 by an increase of intracellular Ca2+ concentration ([Ca2+]i). These responses were abolished by Piezo1 antagonist GsMTx4. Immunoblots showed elevated Piezo1 protein in DRG proximal to peripheral nerve injury-induced painful neuropathy, while PSNs and SGCs from rats with neuropathic pain showed greater Yuda1-evoked elevation of [Ca2+]i and an increased frequency of cells responding to Yoda1, compared to controls. Ipsilateral sciatic nerve application of GsMTx4 alleviated mechanical hypersensitivity following nerve injury. Overall, our data show that Piezo1 is widely expressed by the neuronal and non-neuronal cells in the peripheral sensory pathways and that painful nerve injury is associated with activation of Piezo1 in PSNs and peripheral glia cells.

scholarly journals Plasticity-Related PKMζSignaling in the Insular Cortex Is Involved in the Modulation of Neuropathic Pain after Nerve Injury

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jeongsoo Han ◽  
Minjee Kwon ◽  
Myeounghoon Cha ◽  
Motomasa Tanioka ◽  
Seong-Karp Hong ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Neuropathic Pain ◽  
Nerve Injury ◽  
Neural Plasticity ◽  
Mechanical Allodynia ◽  
Insular Cortex ◽  
Long Term Potentiation ◽  
Inhibitory Peptide ◽  
Term Potentiation ◽  
Potential Applications

The insular cortex (IC) is associated with important functions linked with pain and emotions. According to recent reports, neural plasticity in the brain including the IC can be induced by nerve injury and may contribute to chronic pain. Continuous active kinase, protein kinase Mζ(PKMζ), has been known to maintain the long-term potentiation. This study was conducted to determine the role of PKMζin the IC, which may be involved in the modulation of neuropathic pain. Mechanical allodynia test and immunohistochemistry (IHC) of zif268, an activity-dependent transcription factor required for neuronal plasticity, were performed after nerve injury. Afterζ-pseudosubstrate inhibitory peptide (ZIP, a selective inhibitor of PKMζ) injection, mechanical allodynia test and immunoblotting of PKMζ, phospho-PKMζ(p-PKMζ), and GluR1 and GluR2 were observed. IHC demonstrated that zif268 expression significantly increased in the IC after nerve injury. Mechanical allodynia was significantly decreased by ZIP microinjection into the IC. The analgesic effect lasted for 12 hours. Moreover, the levels of GluR1, GluR2, and p-PKMζwere decreased after ZIP microinjection. These results suggest that peripheral nerve injury induces neural plasticity related to PKMζand that ZIP has potential applications for relieving chronic pain.

Sortilins in neuropathic pain

2012 ◽  
Vol 3 (3) ◽  
pp. 183-184
Author(s):  
M. Richner ◽  
O.J. Bjerrum ◽  
Y. De Koninck ◽  
A. Nykjaer ◽  
C.B. Vaegter
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Mechanical Allodynia ◽  
Molecular Mechanisms ◽  
Intrathecal Injection ◽  
Ion Concentration ◽  
Down Regulation

AbstractBackground/aimsThe molecular mechanisms underlying neuropathic pain are incompletely understood, but recent data suggest that down-regulation of the chloride extruding co-transporter KCC2 in spinal cord sensory neurons is critical: Following peripheral nerve injury, activated microglia in the spinal cord release BDNF, which stimulates neuronal TrkB receptors and ultimately results in the reduction of KCC2 levels. Consequently, neuronal intracellular chloride ion concentration increases, impairing GABAA-receptor mediated inhibition. We have previously described how the receptor sortilin modulates neurotrophin signaling by facilitating anterograde transport of Trk receptors. Unpublished data further link SorCS2, another member of the Sortilins family of sorting receptors (sortilin, SorLA and SorCS1–3) to BDNF signaling by regulating presynaptic TrkB trafficking. The purpose of this study is to explore the involvement of Sortilins in neuropathic pain.MethodsWe subjected wild-type (wt), sortilin knockout (Sort1-/-) and SorCS2 knockout (SorCS2-/-) mice to the Spared Nerve Injury (SNI) model of peripheral nerve injury. Mechanical allodynia was measured by von Frey filaments using the up-down-up method and a 3-out-of-5 thresshold.ResultsAs previously described by several groups, wt mice developed significant mechanical allodynia following SNI. Interestingly however, mice lacking sortilin or SorCS2 were fully protected from development of allodynia and did not display KCC2 down-regulation following injury. In addition, a single intrathecal injection of antibodies against sortilin or SorCS2 could delay or rescue mechanical allodynia in wt SNI mice for 2-3 days. Finally, neither sortilin nor SorCS2 deficient mice responded to intrathecal injection of BDNF, in contrast to wt mice which developed transient mechanical allodynia.ConclusionWe hypothesize that sortilin and SorCS2 are involved in neuropathic pain development by regulating TrkB signaling. Alternatively, Sortilins may directly influence the regulation of KCC2 membrane levels following injury. Both hypotheses are currently being investigated by our group.

Comprehensive analysis of neurobehavior associated with histomorphological alterations in a chronic constrictive nerve injury model through use of the CatWalk XT system

2014 ◽  
Vol 120 (1) ◽  
pp. 250-262 ◽  
Author(s):  
Chien-Yi Chiang ◽  
Meei-Ling Sheu ◽  
Fu-Chou Cheng ◽  
Chun-Jung Chen ◽  
Hong-Lin Su ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Nerve Injury ◽  
Mechanical Allodynia ◽  
S100 Protein ◽  
Thermal Hyperalgesia ◽  
Nerve Damage ◽  
Dorsal Spinal Cord ◽  
Sensory Evoked ◽  
Dorsal Spinal

Object Neuropathic pain is debilitating, and when chronic, it significantly affects the patient physically, psychologically, and socially. The neurobehavior of animals used as a model for chronic constriction injury seems analogous to the neurobehavior of humans with neuropathic pain. However, no data depicting the severity of histomorphological alterations of the nervous system associated with graded changes in neurobehavior are available. To determine the severity of histomorphological alteration related to neurobehavior, the authors created a model of chronic constrictive injury of varying intensity in rats and used the CatWalk XT system to evaluate neurobehavior. Methods A total of 60 Sprague-Dawley rats, weighing 250–300 g each, were randomly assigned to 1 of 5 groups that would receive sham surgery or 1, 2, 3, or 4 ligatures of 3-0 chromic gut loosely ligated around the left sciatic nerve. Neurobehavior was assessed by CatWalk XT, thermal hyperalgesia, and mechanic allodynia before injury and periodically after injury. The nerve tissue from skin to dorsal spinal cord was obtained for histomorphological analysis 1 week after injury, and brain evoked potentials were analyzed 4 weeks after injury. Results. Significant differences in expression of nerve growth factor existed in skin, and the differences were associated with the intensity of nerve injury. After injury, expression of cluster of differentiation 68 and tumor necrosis factor–α was increased, and expression of S100 protein in the middle of the injured nerve was decreased. Increased expression of synaptophysin in the dorsal root ganglion and dorsal spinal cord correlated with the intensity of injury. The amplitude of sensory evoked potential increased with greater severity of nerve damage. Mechanical allodynia and thermal hyperalgesia did not differ significantly among treatment groups at various time points. CatWalk XT gait analysis indicated significant differences for print areas, maximum contact maximum intensity, stand phase, swing phase, single stance, and regular index, with sham and/or intragroup comparisons. Conclusions. Histomorphological and electrophysiological alterations were associated with severity of nerve damage. Subtle neurobehavioral differences were detected by the CatWalk XT system but not by mechanical allodynia or thermal hyperalgesia. Thus, the CatWalk XT system should be a useful tool for monitoring changes in neuropathic pain, especially subtle alterations.

scholarly journals Resveratrol Mediates Mechanical Allodynia Through Modulating Inflammatory Response via the TREM2-autophagy Axis in SNI Rat Model

2020 ◽  
Author(s):  
Yaping Wang ◽  
Yu Shi ◽  
Yongquan Huang ◽  
Wei Liu ◽  
Guiyuan Cai ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Inflammatory Response ◽  
Dorsal Horn ◽  
Nerve Injury ◽  
Rat Model ◽  
Mechanical Allodynia ◽  
Spinal Dorsal Horn ◽  
Intrathecal Administration ◽  
Spared Nerve Injury ◽  
Spinal Dorsal

Abstract Background Neuropathic pain (NeuP) is a chronic and challenging clinical problem, with little effective treatment. Resveratrol has shown neuroprotection by inhibiting inflammatory response in NeuP. Recently, the triggering receptor expressed on myeloid cells 2 (TREM2) expressed by microglia was identified as a critical factor of inflammation in nervous system diseases. In this study, we explored whether resveratrol could ameliorate neuroinflammation and produce anti-mechanical allodynia effects via regulating TREM2 in spared nerve injury rats, as well as investigated the underlying mechanisms. Methods A spared nerve injury (SNI) rat model was performed to investigate whether resveratrol could exert anti-mechanism allodynia effects via inhibiting neuroinflammation. To evaluate the role of TREM2 in anti-neuroinflammatory function of resveratrol, Lentivirus coding TREM2 was intrathecal injected into SNI rats to activate TREM2 and the pain behavior was detected by the Von Frey test. Furthermore, 3-Methyladenine (3-MA, an autophagy inhibitor) was performed to analyze the molecular mechanisms of resveratrol-mediated anti-neuroinflammation using Western blot, qPCR, immunofluorescence. Results The TREM2 expression and number of the microglial cell was significantly increased in the ipsilateral spinal dorsal horn after SNI. We found that intrathecal administration of resveratrol (300ug/day) alleviated mechanical allodynia; obviously enhanced autophagy; and markedly reduced the levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α in the ipsilateral spinal dorsal horn after SNI. Moreover, the number of Iba-1+ microglial cells and TREM2 expression were downregulated after resveratrol treatment. Intrathecal administration of lentivirus coding TREM2 and/or 3-methyladenine in those rats induced deficiencies in resveratrol-mediated anti-inflammation, leading to mechanical allodynia that could be rescued via administration of Res. Furthermore, 3-MA treatment contributed to TREM2-mediated mechanical allodynia. Conclusions Taken together, these data reveal that resveratrol relieves neuropathic pain through suppressing microglia-mediated neuroinflammation via regulating the TREM2-autophagy axis in SNI rats.

scholarly journals ARA290, a Peptide Derived from the Tertiary Structure of Erythropoietin, Produces Long-term Relief of Neuropathic Pain

2011 ◽  
Vol 115 (5) ◽  
pp. 1084-1092 ◽  
Author(s):  
Maarten Swartjes ◽  
Aurora Morariu ◽  
Marieke Niesters ◽  
Michael Brines ◽  
Anthony Cerami ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Tertiary Structure ◽  
Cold Allodynia ◽  
Cardiovascular Side Effects ◽  
Common Receptor ◽  
Rats And Mice

Background Exogenous erythropoietin inhibits development of allodynia in experimental painful neuropathy because of its antiinflammatory and neuroprotective properties at spinal, supraspinal, and possibly peripheral sites. The authors assess the effect of a nonhematopoietic erythropoietin analog, ARA290, on tactile and cold allodynia in a model of neuropathic pain (spared nerve injury) in rats and mice lacking the β-common receptor (βcR mice), a component of the receptor complex mediating tissue protection. Methods Twenty-four hours after peripheral nerve injury, rats and mice were injected with ARA290 or vehicle (five 30-μg/kg intraperitoneal injections at 2-day intervals, followed by once/week, n = 8/group). In a separate group of eight rats, ARA290 treatment was restricted to five doses during the initial 2 weeks after surgery. Results In rats, irrespective of treatment paradigm, ARA290 produced effective, long-term (as long as 15 weeks) relief of tactile and cold allodynia (P < 0.001 vs. vehicle-treated animals). ARA290 was effective in wild-type mice, producing significant relief of allodynia. In contrast, in βcR mice no effect of ARA290 was observed. Conclusions ARA290 produces long-term relief of allodynia because of activation of the β-common receptor. It is argued that relief of neuropathic pain attributable to ARA290 treatment is related to its antiinflammatory properties, possibly within the central nervous system. Because ARA290, in contrast to erythropoietin, is devoid of hematopoietic and cardiovascular side effects, ARA290 is a promising new drug in the prevention of peripheral nerve injury-induced neuropathic pain in humans.

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