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Wu L, Tang H. The role of N6-methyladenosine modification in rodent models of neuropathic pain: from the mechanism to therapeutic potential. Biomed Pharmacother 2023; 166:115398. [PMID: 37647691 DOI: 10.1016/j.biopha.2023.115398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 08/25/2023] [Accepted: 08/26/2023] [Indexed: 09/01/2023] Open
Abstract
Neuropathic pain (NP) is a common chronic pain condition resulted from lesions or diseases of somatosensory nervous system, but the pathogenesis remains unclear. A growing body of evidence supports the relationship between pathogenesis and N6-methyladenosine (m6A) modifications of RNA. However, studies on the role of m6A modifications in NP are still at an early stage. Elucidating different etiologies is important for understanding the specific pathogenesis of NP. This article provides a comprehensive review on the role of m6A methylation modifications including methyltransferases ("writers"), demethylases ("erasers"), and m6A binding proteins ("readers") in NP models. Further analysis of the pathogenic mechanism relationship between m6A and NP provided novel theoretical and practical significance for clinical treatment of NP.
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Affiliation(s)
- Liping Wu
- Guangxi University of Traditional Chinese Medicine, Nanning, China; The First Clinical Medical College of Guangxi University of Traditional Chinese Medicine, Nanning, China
| | - Hongliang Tang
- Guangxi Traditional Chinese Medicine University Affiliated Fangchenggang Hospital.
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2
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Mitchell ME, Cook LC, Shiers S, Tavares-Ferreira D, Akopian AN, Dussor G, Price TJ. Characterization of Fragile X Mental Retardation Protein expression in human nociceptors and their axonal projections to the spinal dorsal horn. J Comp Neurol 2023; 531:814-835. [PMID: 36808110 PMCID: PMC10038933 DOI: 10.1002/cne.25463] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/20/2022] [Accepted: 01/27/2023] [Indexed: 02/23/2023]
Abstract
Fragile X Mental Retardation Protein (FMRP) regulates activity-dependent RNA localization and local translation to modulate synaptic plasticity throughout the central nervous system. Mutations in the FMR1 gene that hinder or ablate FMRP function cause Fragile X Syndrome (FXS), a disorder associated with sensory processing dysfunction. FXS premutations are associated with increased FMRP expression and neurological impairments including sex dimorphic presentations of chronic pain. In mice, FMRP ablation causes dysregulated dorsal root ganglion (DRG) neuron excitability and synaptic vesicle exocytosis, spinal circuit activity, and decreased translation-dependent nociceptive sensitization. Activity-dependent, local translation is a key mechanism for enhancing primary nociceptor excitability that promotes pain in animals and humans. These works indicate that FMRP likely regulates nociception and pain at the level of the primary nociceptor or spinal cord. Therefore, we sought to better understand FMRP expression in the human DRG and spinal cord using immunostaining in organ donor tissues. We find that FMRP is highly expressed in DRG and spinal neuron subsets with substantia gelatinosa exhibiting the most abundant immunoreactivity in spinal synaptic fields. Here, it is expressed in nociceptor axons. FMRP puncta colocalized with Nav1.7 and TRPV1 receptor signals suggesting a pool of axoplasmic FMRP localizes to plasma membrane-associated loci in these branches. Interestingly, FMRP puncta exhibited notable colocalization with calcitonin gene-related peptide (CGRP) immunoreactivity selectively in female spinal cord. Our results support a regulatory role for FMRP in human nociceptor axons of the dorsal horn and implicate it in the sex dimorphic actions of CGRP signaling in nociceptive sensitization and chronic pain.
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Affiliation(s)
- Molly E Mitchell
- Center for Advanced Pain Studies, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Lauren C Cook
- Center for Advanced Pain Studies, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Stephanie Shiers
- Center for Advanced Pain Studies, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Diana Tavares-Ferreira
- Center for Advanced Pain Studies, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Armen N Akopian
- Department of Endodontics, UT Health San Antonio, San Antonio, Texas, USA
| | - Gregory Dussor
- Center for Advanced Pain Studies, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Theodore J Price
- Center for Advanced Pain Studies, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, USA
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Morales P, Muller C, Jagerovic N, Reggio PH. Targeting CB2 and TRPV1: Computational Approaches for the Identification of Dual Modulators. Front Mol Biosci 2022; 9:841190. [PMID: 35281260 PMCID: PMC8914543 DOI: 10.3389/fmolb.2022.841190] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/03/2022] [Indexed: 11/13/2022] Open
Abstract
Both metabotropic (CBRs) and ionotropic cannabinoid receptors (ICRs) have implications in a range of neurological disorders. The metabotropic canonical CBRs CB1 and CB2 are highly implicated in these pathological events. However, selective targeting at CB2 versus CB1 offers optimized pharmacology due to the absence of psychoactive outcomes. The ICR transient receptor potential vanilloid type 1 (TRPV1) has also been reported to play a role in CNS disorders. Thus, activation of both targets, CB2 and TRPV1, offers a promising polypharmacological strategy for the treatment of neurological events including analgesia and neuroprotection. This brief research report aims to identify chemotypes with a potential dual CB2/TRPV1 profile. For this purpose, we have rationalized key structural features for activation and performed virtual screening at both targets using curated chemical libraries.
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Affiliation(s)
- Paula Morales
- Medicinal Chemistry Institute, Spanish National Research Council, Madrid, Spain
| | - Chanté Muller
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, United States
| | - Nadine Jagerovic
- Medicinal Chemistry Institute, Spanish National Research Council, Madrid, Spain
| | - Patricia H. Reggio
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, United States
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Deng PY, Avraham O, Cavalli V, Klyachko VA. Hyperexcitability of Sensory Neurons in Fragile X Mouse Model. Front Mol Neurosci 2022; 14:796053. [PMID: 35002623 PMCID: PMC8727524 DOI: 10.3389/fnmol.2021.796053] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/17/2021] [Indexed: 01/18/2023] Open
Abstract
Sensory hypersensitivity and somatosensory deficits represent the core symptoms of Fragile X syndrome (FXS). These alterations are believed to arise from changes in cortical sensory processing, while potential deficits in the function of peripheral sensory neurons residing in dorsal root ganglia remain unexplored. We found that peripheral sensory neurons exhibit pronounced hyperexcitability in Fmr1 KO mice, manifested by markedly increased action potential (AP) firing rate and decreased threshold. Unlike excitability changes found in many central neurons, no significant changes were observed in AP rising and falling time, peak potential, amplitude, or duration. Sensory neuron hyperexcitability was caused primarily by increased input resistance, without changes in cell capacitance or resting membrane potential. Analyses of the underlying mechanisms revealed reduced activity of HCN channels and reduced expression of HCN1 and HCN4 in Fmr1 KO compared to WT. A selective HCN channel blocker abolished differences in all measures of sensory neuron excitability between WT and Fmr1 KO neurons. These results reveal a hyperexcitable state of peripheral sensory neurons in Fmr1 KO mice caused by dysfunction of HCN channels. In addition to the intrinsic neuronal dysfunction, the accompanying paper examines deficits in sensory neuron association/communication with their enveloping satellite glial cells, suggesting contributions from both neuronal intrinsic and extrinsic mechanisms to sensory dysfunction in the FXS mouse model.
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Affiliation(s)
- Pan-Yue Deng
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Oshri Avraham
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Valeria Cavalli
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States.,Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, United States.,Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Vitaly A Klyachko
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States.,Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, United States
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Pirbhoy PS, Jonak CR, Syed R, Argueta DA, Perez PA, Wiley MB, Hessamian K, Lovelace JW, Razak KA, DiPatrizio NV, Ethell IM, Binder DK. Increased 2-arachidonoyl-sn-glycerol levels normalize cortical responses to sound and improve behaviors in Fmr1 KO mice. J Neurodev Disord 2021; 13:47. [PMID: 34645383 PMCID: PMC8513313 DOI: 10.1186/s11689-021-09394-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/20/2021] [Indexed: 01/08/2023] Open
Abstract
Background Individuals with Fragile X syndrome (FXS) and autism spectrum disorder (ASD) exhibit an array of symptoms, including sociability deficits, increased anxiety, hyperactivity, and sensory hyperexcitability. It is unclear how endocannabinoid (eCB) modulation can be targeted to alleviate neurophysiological abnormalities in FXS as behavioral research reveals benefits to inhibiting cannabinoid (CB) receptor activation and increasing endocannabinoid ligand levels. Here, we hypothesize that enhancement of 2-arachidonoyl-sn-glycerol (2-AG) in Fragile X mental retardation 1 gene knock-out (Fmr1 KO) mice may reduce cortical hyperexcitability and behavioral abnormalities observed in FXS. Methods To test whether an increase in 2-AG levels normalized cortical responses in a mouse model of FXS, animals were subjected to electroencephalography (EEG) recording and behavioral assessment following treatment with JZL-184, an irreversible inhibitor of monoacylglycerol lipase (MAGL). Assessment of 2-AG was performed using lipidomic analysis in conjunction with various doses and time points post-administration of JZL-184. Baseline electrocortical activity and evoked responses to sound stimuli were measured using a 30-channel multielectrode array (MEA) in adult male mice before, 4 h, and 1 day post-intraperitoneal injection of JZL-184 or vehicle. Behavior assessment was done using the open field and elevated plus maze 4 h post-treatment. Results Lipidomic analysis showed that 8 mg/kg JZL-184 significantly increased the levels of 2-AG in the auditory cortex of both Fmr1 KO and WT mice 4 h post-treatment compared to vehicle controls. EEG recordings revealed a reduction in the abnormally enhanced baseline gamma-band power in Fmr1 KO mice and significantly improved evoked synchronization to auditory stimuli in the gamma-band range post-JZL-184 treatment. JZL-184 treatment also ameliorated anxiety-like and hyperactivity phenotypes in Fmr1 KO mice. Conclusions Overall, these results indicate that increasing 2-AG levels may serve as a potential therapeutic approach to normalize cortical responses and improve behavioral outcomes in FXS and possibly other ASDs. Supplementary Information The online version contains supplementary material available at 10.1186/s11689-021-09394-x.
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Affiliation(s)
- Patricia S Pirbhoy
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Carrie R Jonak
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Rashid Syed
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Donovan A Argueta
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Pedro A Perez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Mark B Wiley
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Keon Hessamian
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Jonathan W Lovelace
- Department of Psychology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Khaleel A Razak
- Department of Psychology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Nicholas V DiPatrizio
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Iryna M Ethell
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Devin K Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA.
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Johnson D, Santos E, Kim K, Ponzini MD, McLennan YA, Schneider A, Tassone F, Hagerman RJ. Increased Pain Symptomatology Among Females vs. Males With Fragile X-Associated Tremor/Ataxia Syndrome. Front Psychiatry 2021; 12:762915. [PMID: 35126193 PMCID: PMC8811376 DOI: 10.3389/fpsyt.2021.762915] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 12/27/2021] [Indexed: 12/12/2022] Open
Abstract
Individuals with the fragile X premutation report symptoms of chronic pain from multiple systems, have increased incidence of comorbid conditions where pain is a prominent feature, and pathophysiology that supports disrupted pain regulation, inflammation, and energy imbalance. Less is known about how pain manifests for the subpopulation of carriers that develop the motor and cognitive changes of fragile X-associated tremor and ataxia syndrome (FXTAS), and how pain may differ between men and women. We gathered data collected from 104 males and females with FXTAS related to chronic pain, comorbid conditions related to pain, and medications used for pain control to further explore the types of pain experienced and to better characterize how individuals with the fragile X premutation experience pain sensation across genders. We found that women experience significantly more pain symptoms than men, particularly allodynia (20 vs. 2.0%, p = 0.008), peripheral neuropathy pain (43.9 vs. 25.4%, p = 0.0488), migraine (43.9 vs. 14.5%, p = 0.0008), fibromyalgia (26.8 vs. 0%, p = 0.0071) and back pain (48.5 vs. 23.4%, p = 0.008). We found onset of peripheral neuropathy predicts the onset of ataxia (β = 0.63 ± 0.25, p = 0.019) and tremor (β = 0.56 ± 0.17, p = 0.004) across gender. Women also report significantly more anxiety (82.9 vs. 39.7%, p < 0.001), which has implications for ideal pain treatment. These pain symptoms need to be recognized in the medical history and treated appropriately, with consideration for overlapping comorbidities.
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Affiliation(s)
- Devon Johnson
- Medical Investigation of Neurodevelopmental Disorders Institute, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Ellery Santos
- Medical Investigation of Neurodevelopmental Disorders Institute, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Kyoungmi Kim
- Medical Investigation of Neurodevelopmental Disorders Institute, School of Medicine, University of California, Davis, Davis, CA, United States.,Division of Biostatistics, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Matthew D Ponzini
- Medical Investigation of Neurodevelopmental Disorders Institute, School of Medicine, University of California, Davis, Davis, CA, United States.,Division of Biostatistics, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Yingratana A McLennan
- Medical Investigation of Neurodevelopmental Disorders Institute, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Andrea Schneider
- Medical Investigation of Neurodevelopmental Disorders Institute, School of Medicine, University of California, Davis, Davis, CA, United States.,Department of Pediatrics, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Flora Tassone
- Medical Investigation of Neurodevelopmental Disorders Institute, School of Medicine, University of California, Davis, Davis, CA, United States.,Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders Institute, School of Medicine, University of California, Davis, Davis, CA, United States.,Department of Pediatrics, School of Medicine, University of California, Davis, Davis, CA, United States
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