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Pozzi E, Terribile G, Cherchi L, Di Girolamo S, Sancini G, Alberti P. Ion Channel and Transporter Involvement in Chemotherapy-Induced Peripheral Neurotoxicity. Int J Mol Sci 2024; 25:6552. [PMID: 38928257 PMCID: PMC11203899 DOI: 10.3390/ijms25126552] [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: 04/21/2024] [Revised: 06/06/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
The peripheral nervous system can encounter alterations due to exposure to some of the most commonly used anticancer drugs (platinum drugs, taxanes, vinca alkaloids, proteasome inhibitors, thalidomide), the so-called chemotherapy-induced peripheral neurotoxicity (CIPN). CIPN can be long-lasting or even permanent, and it is detrimental for the quality of life of cancer survivors, being associated with persistent disturbances such as sensory loss and neuropathic pain at limb extremities due to a mostly sensory axonal polyneuropathy/neuronopathy. In the state of the art, there is no efficacious preventive/curative treatment for this condition. Among the reasons for this unmet clinical and scientific need, there is an uncomplete knowledge of the pathogenetic mechanisms. Ion channels and transporters are pivotal elements in both the central and peripheral nervous system, and there is a growing body of literature suggesting that they might play a role in CIPN development. In this review, we first describe the biophysical properties of these targets and then report existing data for the involvement of ion channels and transporters in CIPN, thus paving the way for new approaches/druggable targets to cure and/or prevent CIPN.
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Affiliation(s)
- Eleonora Pozzi
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
| | - Giulia Terribile
- Human Physiology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.T.); (G.S.)
| | - Laura Cherchi
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
| | - Sara Di Girolamo
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
| | - Giulio Sancini
- Human Physiology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.T.); (G.S.)
| | - Paola Alberti
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
- Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy
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Stewart RG, Marquis MJ, Jo S, Aberra A, Cook V, Whiddon Z, Ferns M, Sack JT. A Kv2 inhibitor combination reveals native neuronal conductances consistent with Kv2/KvS heteromers. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.31.578214. [PMID: 38352561 PMCID: PMC10862871 DOI: 10.1101/2024.01.31.578214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
KvS proteins are voltage-gated potassium channel subunits that form functional channels when assembled into heterotetramers with Kv2.1 ( KCNB1 ) or Kv2.2 ( KCNB2 ). Mammals have 10 KvS subunits: Kv5.1 ( KCNF1 ), Kv6.1 ( KCNG1 ), Kv6.2 ( KCNG2 ), Kv6.3 ( KCNG3 ), Kv6.4 ( KCNG4 ), Kv8.1 ( KCNV1 ), Kv8.2 ( KCNV2 ), Kv9.1 ( KCNS1 ), Kv9.2 ( KCNS2 ), and Kv9.3 ( KCNS3 ). Electrically excitable cells broadly express channels containing Kv2 subunits and most neurons have substantial Kv2 conductance. However, whether KvS subunits contribute to these conductances has not been clear, leaving the physiological roles of KvS subunits poorly understood. Here, we identify that two potent Kv2 inhibitors, used in combination, can distinguish conductances of Kv2/KvS channels and Kv2-only channels. We find that Kv5, Kv6, Kv8, or Kv9-containing channels are resistant to the Kv2-selective pore-blocker RY785 yet remain sensitive to the Kv2-selective voltage sensor modulator guangxitoxin-1E (GxTX). Using these inhibitors in mouse superior cervical ganglion neurons, we find that little of the Kv2 conductance is carried by KvS-containing channels. In contrast, conductances consistent with KvS-containing channels predominate over Kv2-only channels in mouse and human dorsal root ganglion neurons. These results establish an approach to pharmacologically distinguish conductances of Kv2/KvS heteromers from Kv2-only channels, enabling investigation of the physiological roles of endogenous KvS subunits. These findings suggest that drugs targeting KvS subunits could modulate electrical activity of subsets of Kv2-expressing cell types.
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Wang Q, Ye Y, Yang L, Xiao L, Liu J, Zhang W, Du G. Painful diabetic neuropathy: The role of ion channels. Biomed Pharmacother 2024; 173:116417. [PMID: 38490158 DOI: 10.1016/j.biopha.2024.116417] [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: 11/30/2023] [Revised: 03/06/2024] [Accepted: 03/06/2024] [Indexed: 03/17/2024] Open
Abstract
Painful diabetic neuropathy (PDN) is a common chronic complication of diabetes that causes neuropathic pain and negatively affects the quality of life. The management of PDN is far from satisfactory. At present, interventions are primarily focused on symptomatic treatment. Ion channel disorders are a major cause of PDN, and a complete understanding of their roles and mechanisms may provide better options for the clinical treatment of PDN. Therefore, this review summarizes the important role of ion channels in PDN and the current drug development targeting these ion channels.
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Affiliation(s)
- Qi Wang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, China; National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Yifei Ye
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, China; National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Linghui Yang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, China; National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Lifan Xiao
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, China; National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Jin Liu
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, China; National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Wensheng Zhang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, China; National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.
| | - Guizhi Du
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, China; National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.
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4
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Stewart RG, Camacena M, Copits BA, Sack JT. Distinct cellular expression and subcellular localization of Kv2 voltage-gated K + channel subtypes in dorsal root ganglion neurons conserved between mice and humans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.01.530679. [PMID: 38187582 PMCID: PMC10769185 DOI: 10.1101/2023.03.01.530679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The distinct organization of Kv2 voltage-gated potassium channels on and near the cell body of brain neurons enables their regulation of action potentials and specialized membrane contact sites. Somatosensory neurons have a pseudounipolar morphology and transmit action potentials from peripheral nerve endings through axons that bifurcate to the spinal cord and the cell body within ganglia including the dorsal root ganglia (DRG). Kv2 channels regulate action potentials in somatosensory neurons, yet little is known about where Kv2 channels are located. Here we define the cellular and subcellular localization of the Kv2 paralogs, Kv2.1 and Kv2.2, in DRG somatosensory neurons with a panel of antibodies, cell markers, and genetically modified mice. We find that relative to spinal cord neurons, DRG neurons have similar levels of detectable Kv2.1, and higher levels of Kv2.2. In older mice, detectable Kv2.2 remains similar while detectable Kv2.1 decreases. Both Kv2 subtypes adopt clustered subcellular patterns that are distinct from central neurons. Most DRG neurons co-express Kv2.1 and Kv2.2, although neuron subpopulations show preferential expression of Kv2.1 or Kv2.2. We find that Kv2 protein expression and subcellular localization is similar between mouse and human DRG neurons. We conclude that the organization of both Kv2 channels is consistent with physiological roles in the somata and stem axons of DRG neurons. The general prevalence of Kv2.2 in DRG as compared to central neurons and the enrichment of Kv2.2 relative to detectable Kv2.1, in older mice, proprioceptors, and axons suggest more widespread roles for Kv2.2 in DRG neurons.
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Affiliation(s)
- Robert G Stewart
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
| | - Miriam Camacena
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
| | - Bryan A Copits
- Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jon T Sack
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
- Department of Anesthesiology and Pain Medicine, University of California Davis, Davis, CA 95616, USA
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Shehab S, Javed H, Johnson AM, Tariq S, Kumar CA, Emerald BS. Unveiling the mechanisms of neuropathic pain suppression: perineural resiniferatoxin targets Trpv1 and beyond. Front Neuroanat 2023; 17:1306180. [PMID: 38099210 PMCID: PMC10720729 DOI: 10.3389/fnana.2023.1306180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/10/2023] [Indexed: 12/17/2023] Open
Abstract
Neuropathic pain arises from damage or disorders affecting the somatosensory system. In rats, L5 nerve injury induces thermal and mechanical hypersensitivity/hyperalgesia. Recently, we demonstrated that applying resiniferatoxin (RTX) directly on uninjured L3 and L4 nerves alleviated thermal and mechanical hypersensitivity resulting from L5 nerve injury. Herein, using immunohistochemistry, Western blot, and qRT-PCR techniques, we reveal that perineural application of RTX (0.002%) on the L4 nerve substantially downregulated the expression of its receptor (Trpv1) and three different voltage-gated ion channels (Nav1.9, Kv4.3, and Cav2.2). These channels are found primarily in small-sized neurons and show significant colocalization with Trpv1 in the dorsal root ganglion (DRG). However, RTX treatment did not affect the expression of Kv1.1, Piezo2 (found in large-sized neurons without colocalization with Trpv1), and Kir4.1 (localized in satellite cells) in the ipsilateral DRGs. Furthermore, RTX application on L3 and L4 nerves reduced the activation of c-fos in the spinal neurons induced by heat stimulation. Subsequently, we investigated whether applying RTX to the L3 and L4 nerves 3 weeks before the L5 nerve injury could prevent the onset of neuropathic pain. Both 0.002 and 0.004% concentrations of RTX produced significant analgesic effects, while complete prevention of thermal and mechanical hypersensitivity required a concentration of 0.008%. Importantly, this preventive effect on neuropathic manifestations was not associated with nerve degeneration, as microscopic examination revealed no morphological changes. Overall, this study underscores the mechanisms and the significance of perineural RTX treatment applied to adjacent uninjured nerves in entirely preventing nerve injury-induced neuropathic pain in humans and animals.
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Affiliation(s)
- Safa Shehab
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
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6
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Ślęczkowska M, Misra K, Santoro S, Gerrits MM, Hoeijmakers JGJ. Ion Channel Genes in Painful Neuropathies. Biomedicines 2023; 11:2680. [PMID: 37893054 PMCID: PMC10604193 DOI: 10.3390/biomedicines11102680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
Neuropathic pain (NP) is a typical symptom of peripheral nerve disorders, including painful neuropathy. The biological mechanisms that control ion channels are important for many cell activities and are also therapeutic targets. Disruption of the cellular mechanisms that govern ion channel activity can contribute to pain pathophysiology. The voltage-gated sodium channel (VGSC) is the most researched ion channel in terms of NP; however, VGSC impairment is detected in only <20% of painful neuropathy patients. Here, we discuss the potential role of the other peripheral ion channels involved in sensory signaling (transient receptor potential cation channels), neuronal excitation regulation (potassium channels), involuntary action potential generation (hyperpolarization-activated cyclic nucleotide-gated channels), thermal pain (anoctamins), pH modulation (acid sensing ion channels), and neurotransmitter release (calcium channels) related to pain and their prospective role as therapeutic targets for painful neuropathy.
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Affiliation(s)
- Milena Ślęczkowska
- Department of Toxicogenomics, Maastricht University, 6229 ER Maastricht, The Netherlands;
- Department of Neurology, School of Mental Health and Neuroscience, Maastricht University Medical Centre+, 6229 ER Maastricht, The Netherlands
| | - Kaalindi Misra
- Laboratory of Human Genetics of Neurological Disorders, IRCCS San Raffaele Scientific Institute, INSPE, 20132 Milan, Italy; (K.M.); (S.S.)
| | - Silvia Santoro
- Laboratory of Human Genetics of Neurological Disorders, IRCCS San Raffaele Scientific Institute, INSPE, 20132 Milan, Italy; (K.M.); (S.S.)
| | - Monique M. Gerrits
- Department of Clinical Genetics, Maastricht University Medical Centre+, 6229 HX Maastricht, The Netherlands;
| | - Janneke G. J. Hoeijmakers
- Department of Neurology, School of Mental Health and Neuroscience, Maastricht University Medical Centre+, 6229 ER Maastricht, The Netherlands
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7
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Ovsepian SV, Waxman SG. Gene therapy for chronic pain: emerging opportunities in target-rich peripheral nociceptors. Nat Rev Neurosci 2023; 24:252-265. [PMID: 36658346 DOI: 10.1038/s41583-022-00673-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2022] [Indexed: 01/20/2023]
Abstract
With sweeping advances in precision delivery systems and manipulation of the genomes and transcriptomes of various cell types, medical biotechnology offers unprecedented selectivity for and control of a wide variety of biological processes, forging new opportunities for therapeutic interventions. This perspective summarizes state-of-the-art gene therapies enabled by recent innovations, with an emphasis on the expanding universe of molecular targets that govern the activity and function of primary sensory neurons and which might be exploited to effectively treat chronic pain.
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Affiliation(s)
- Saak V Ovsepian
- School of Science, Faculty of Engineering and Science, University of Greenwich London, Chatham Maritime, UK.
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA.
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA.
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8
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Nutraceuticals: A source of benefaction for neuropathic pain and fibromyalgia. J Funct Foods 2022. [DOI: 10.1016/j.jff.2022.105260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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9
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Alles SRA, Smith PA. Peripheral Voltage-Gated Cation Channels in Neuropathic Pain and Their Potential as Therapeutic Targets. FRONTIERS IN PAIN RESEARCH 2022; 2:750583. [PMID: 35295464 PMCID: PMC8915663 DOI: 10.3389/fpain.2021.750583] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/10/2021] [Indexed: 11/25/2022] Open
Abstract
The persistence of increased excitability and spontaneous activity in injured peripheral neurons is imperative for the development and persistence of many forms of neuropathic pain. This aberrant activity involves increased activity and/or expression of voltage-gated Na+ and Ca2+ channels and hyperpolarization activated cyclic nucleotide gated (HCN) channels as well as decreased function of K+ channels. Because they display limited central side effects, peripherally restricted Na+ and Ca2+ channel blockers and K+ channel activators offer potential therapeutic approaches to pain management. This review outlines the current status and future therapeutic promise of peripherally acting channel modulators. Selective blockers of Nav1.3, Nav1.7, Nav1.8, Cav3.2, and HCN2 and activators of Kv7.2 abrogate signs of neuropathic pain in animal models. Unfortunately, their performance in the clinic has been disappointing; some substances fail to meet therapeutic end points whereas others produce dose-limiting side effects. Despite this, peripheral voltage-gated cation channels retain their promise as therapeutic targets. The way forward may include (i) further structural refinement of K+ channel activators such as retigabine and ASP0819 to improve selectivity and limit toxicity; use or modification of Na+ channel blockers such as vixotrigine, PF-05089771, A803467, PF-01247324, VX-150 or arachnid toxins such as Tap1a; the use of Ca2+ channel blockers such as TTA-P2, TTA-A2, Z 944, ACT709478, and CNCB-2; (ii) improving methods for assessing “pain” as opposed to nociception in rodent models; (iii) recognizing sex differences in pain etiology; (iv) tailoring of therapeutic approaches to meet the symptoms and etiology of pain in individual patients via quantitative sensory testing and other personalized medicine approaches; (v) targeting genetic and biochemical mechanisms controlling channel expression using anti-NGF antibodies such as tanezumab or re-purposed drugs such as vorinostat, a histone methyltransferase inhibitor used in the management of T-cell lymphoma, or cercosporamide a MNK 1/2 inhibitor used in treatment of rheumatoid arthritis; (vi) combination therapy using drugs that are selective for different channel types or regulatory processes; (vii) directing preclinical validation work toward the use of human or human-derived tissue samples; and (viii) application of molecular biological approaches such as clustered regularly interspaced short palindromic repeats (CRISPR) technology.
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Affiliation(s)
- Sascha R A Alles
- Department of Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Peter A Smith
- Department of Pharmacology, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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10
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Felix R, Muñoz-Herrera D, Corzo-López A, Fernández-Gallardo M, Leyva-Leyva M, González-Ramírez R, Sandoval A. Ion channel long non-coding RNAs in neuropathic pain. Pflugers Arch 2022; 474:457-468. [PMID: 35235008 DOI: 10.1007/s00424-022-02675-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 02/01/2023]
Abstract
Neuropathic pain is one of the primary forms of chronic pain and is the consequence of the somatosensory system's direct injury or disease. It is a relevant public health problem that affects about 10% of the world's general population. In neuropathic pain, alteration in neurotransmission occurs at various levels, including the dorsal root ganglia, the spinal cord, and the brain, resulting from the malfunction of diverse molecules such as receptors, ion channels, and elements of specific intracellular signaling pathways. In this context, there have been exciting advances in elucidating neuropathic pain's cellular and molecular mechanisms in the last decade, including the possible role that long non-coding RNAs (lncRNAs) may play, which open up new alternatives for the development of diagnostic and therapeutic strategies for this condition. This review focuses on recent studies associated with the possible relevance of lncRNAs in the development and maintenance of neuropathic pain through their actions on the functional expression of ion channels. Recognizing the changes in the function and spatio-temporal patterns of expression of these membrane proteins is crucial to understanding the control of neuronal excitability in chronic pain syndromes.
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Affiliation(s)
- Ricardo Felix
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), 07360, Mexico City, Mexico.
| | - David Muñoz-Herrera
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), 07360, Mexico City, Mexico
| | - Alejandra Corzo-López
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), 07360, Mexico City, Mexico
| | | | - Margarita Leyva-Leyva
- Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Mexico City, Mexico
| | - Ricardo González-Ramírez
- Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Mexico City, Mexico
| | - Alejandro Sandoval
- School of Medicine FES Iztacala, National Autonomous University of Mexico (UNAM), Tlalnepantla, Mexico
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Molecular Changes in the Dorsal Root Ganglion during the Late Phase of Peripheral Nerve Injury-induced Pain in Rodents: A Systematic Review. Anesthesiology 2021; 136:362-388. [PMID: 34965284 DOI: 10.1097/aln.0000000000004092] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
The dorsal root ganglion is widely recognized as a potential target to treat chronic pain. A fundamental understanding of quantitative molecular and genomic changes during the late phase of pain is therefore indispensable. The authors performed a systematic literature review on injury-induced pain in rodent dorsal root ganglions at minimally 3 weeks after injury. So far, slightly more than 300 molecules were quantified on the protein or messenger RNA level, of which about 60 were in more than one study. Only nine individual sequencing studies were performed in which the most up- or downregulated genes varied due to heterogeneity in study design. Neuropeptide Y and galanin were found to be consistently upregulated on both the gene and protein levels. The current knowledge regarding molecular changes in the dorsal root ganglion during the late phase of pain is limited. General conclusions are difficult to draw, making it hard to select specific molecules as a focus for treatment.
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12
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Khaitin A. Calcium in Neuronal and Glial Response to Axotomy. Int J Mol Sci 2021; 22:ijms222413344. [PMID: 34948141 PMCID: PMC8706492 DOI: 10.3390/ijms222413344] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022] Open
Abstract
Neurotrauma assumes an instant or delayed disconnection of axons (axotomy), which affects not only neurons, but surrounding glia as well. Not only mechanically injured glia near the site of disconnection, especially transection, is subjected to the damage, but also glia that is remote from the lesion site. Glial cells, which surround the neuronal body, in turn, support neuron survival, so there is a mutual protection between neuron and glia. Calcium signaling is a central mediator of all post-axotomy events, both in neuron and glia, playing a critical role in their survival/regeneration or death/degeneration. The involvement of calcium in post-axotomy survival of the remote, mechanically intact glia is poorly studied. The purpose of this review is to sum up the calcium-involving mechanisms in responses of neurons and glial cells to axotomy to show their importance and to give some suggestions for future research of remote glia in this context.
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Affiliation(s)
- Andrey Khaitin
- Academy of Biology and Biotechnology, Southern Federal University, 344090 Rostov-on-Don, Russia
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13
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Kcns3 deficiency disrupts Parvalbumin neuron physiology in mouse prefrontal cortex: Implications for the pathophysiology of schizophrenia. Neurobiol Dis 2021; 155:105382. [PMID: 33940180 DOI: 10.1016/j.nbd.2021.105382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 01/04/2023] Open
Abstract
The unique fast spiking (FS) phenotype of cortical parvalbumin-positive (PV) neurons depends on the expression of multiple subtypes of voltage-gated potassium channels (Kv). PV neurons selectively express Kcns3, the gene encoding Kv9.3 subunits, suggesting that Kcns3 expression is critical for the FS phenotype. KCNS3 expression is lower in PV neurons in the neocortex of subjects with schizophrenia, but the effects of this alteration are unclear, because Kv9.3 subunit function is poorly understood. Therefore, to assess the role of Kv9.3 subunits in PV neuron function, we combined gene expression analyses, computational modeling, and electrophysiology in acute slices from the cortex of Kcns3-deficient mice. Kcns3 mRNA levels were ~ 50% lower in cortical PV neurons from Kcns3-deficient relative to wildtype mice. While silent per se, Kv9.3 subunits are believed to amplify the Kv2.1 current in Kv2.1-Kv9.3 channel complexes. Hence, to assess the consequences of reducing Kv9.3 levels, we simulated the effects of decreasing the Kv2.1-mediated current in a computational model. The FS cell model with reduced Kv2.1 produced spike trains with irregular inter-spike intervals, or stuttering, and greater Na+ channel inactivation. As in the computational model, PV basket cells (PVBCs) from Kcns3-deficient mice displayed spike trains with strong stuttering, which depressed PVBC firing. Moreover, Kcns3 deficiency impaired the recruitment of PVBC firing at gamma frequency by stimuli mimicking synaptic input observed during cortical UP states. Our data indicate that Kv9.3 subunits are critical for PVBC physiology and suggest that KCNS3 deficiency in schizophrenia could impair PV neuron firing, possibly contributing to deficits in cortical gamma oscillations in the illness.
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14
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Quantitative differences in neuronal subpopulations between mouse and human dorsal root ganglia demonstrated with RNAscope in situ hybridization. Pain 2021; 161:2410-2424. [PMID: 32639368 DOI: 10.1097/j.pain.0000000000001973] [Citation(s) in RCA: 105] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Next-generation transcriptomics in combination with imaging-based approaches have emerged as powerful tools for the characterization of dorsal root ganglion (DRG) neuronal subpopulations. The mouse DRG has been well characterized by many independently conducted studies with convergent findings, but few studies have directly compared expression of population markers between mouse and human. This is important because of our increasing reliance on the mouse as a preclinical model for translational studies. Although calcitonin gene-related peptide (CGRP) and P2X purinergic ion channel type 3 receptor (P2X3R) have been used to define peptidergic and nonpeptidergic nociceptor subpopulations, respectively, in mouse DRG, these populations may be different in other species. To directly test this, as well as a host of other markers, we used multiplex RNAscope in situ hybridization to elucidate the distribution of a multitude of unique and classic neuronal mRNAs in peptidergic (CGRP-expressing) and nonpeptidergic (P2X3R-expressing) nociceptor subpopulations in mouse and human DRG. We found a large overlapping CGRP and P2X3R neuronal subpopulation in human, lumbar DRG that was not present in mouse. We also found differential expression in a variety of mRNAs for transient receptor potential channels, cholinergic receptors, potassium channels, sodium channels, and other markers/targets. These data offer insights into the spatial and functional organization of neuronal cell subpopulations in the rodent and human DRG and support the idea that sensory system organizational principles are likely different between both species.
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Functional Coupling of Slack Channels and P2X3 Receptors Contributes to Neuropathic Pain Processing. Int J Mol Sci 2021; 22:ijms22010405. [PMID: 33401689 PMCID: PMC7795269 DOI: 10.3390/ijms22010405] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/19/2020] [Accepted: 12/29/2020] [Indexed: 12/16/2022] Open
Abstract
The sodium-activated potassium channel Slack (KNa1.1, Slo2.2, or Kcnt1) is highly expressed in populations of sensory neurons, where it mediates the sodium-activated potassium current (IKNa) and modulates neuronal activity. Previous studies suggest that Slack is involved in the processing of neuropathic pain. However, mechanisms underlying the regulation of Slack activity in this context are poorly understood. Using whole-cell patch-clamp recordings we found that Slack-mediated IKNa in sensory neurons of mice is reduced after peripheral nerve injury, thereby contributing to neuropathic pain hypersensitivity. Interestingly, Slack is closely associated with ATP-sensitive P2X3 receptors in a population of sensory neurons. In vitro experiments revealed that Slack-mediated IKNa may be bidirectionally modulated in response to P2X3 activation. Moreover, mice lacking Slack show altered nocifensive responses to P2X3 stimulation. Our study identifies P2X3/Slack signaling as a mechanism contributing to hypersensitivity after peripheral nerve injury and proposes a potential novel strategy for treatment of neuropathic pain.
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16
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Antispasmodic Drug Drofenine as an Inhibitor of Kv2.1 Channel Ameliorates Peripheral Neuropathy in Diabetic Mice. iScience 2020; 23:101617. [PMID: 33089105 PMCID: PMC7559245 DOI: 10.1016/j.isci.2020.101617] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 07/22/2020] [Accepted: 09/23/2020] [Indexed: 12/30/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN) is a common diabetic complication and has yet no efficient medication. Here, we report that antispasmodic drug drofenine (Dfe) blocks Kv2.1 and ameliorates DPN-like pathology in diabetic mice. The underlying mechanisms are investigated against the DPN mice with in vivo Kv2.1 knockdown through adeno associated virus AAV9-Kv2.1-RNAi. Streptozotocin (STZ) induced type 1 or db/db type 2 diabetic mice with DPN exhibited a high level of Kv2.1 protein in dorsal root ganglion (DRG) tissue and a suppressed neurite outgrowth in DRG neuron. Dfe promoted neurite outgrowth by inhibiting Kv2.1 channel and/or Kv2.1 mRNA and protein expression level. Moreover, it suppressed inflammation by repressing IκBα/NF-κB signaling, inhibited apoptosis by regulating Kv2.1-mediated Bcl-2 family proteins and Caspase-3 and ameliorated mitochondrial dysfunction through Kv2.1/CaMKKβ/AMPK/PGC1α pathway. Our work supports that Kv2.1 inhibition is a promisingly therapeutic strategy for DPN and highlights the potential of Dfe in treating this disease. Antispasmodic drug drofenine (Dfe) ameliorates DPN-like pathology in diabetic mice Dfe inhibits Kv2.1 channel and/or Kv2.1 mRNA and protein expression level Dfe represses inflammation, apoptosis, and mitochondrial dysfunction in DPN mice Kv2.1 inhibition is a therapeutic tactic and Dfe shows therapeutic potential for DPN
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17
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Smith PA. K + Channels in Primary Afferents and Their Role in Nerve Injury-Induced Pain. Front Cell Neurosci 2020; 14:566418. [PMID: 33093824 PMCID: PMC7528628 DOI: 10.3389/fncel.2020.566418] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022] Open
Abstract
Sensory abnormalities generated by nerve injury, peripheral neuropathy or disease are often expressed as neuropathic pain. This type of pain is frequently resistant to therapeutic intervention and may be intractable. Numerous studies have revealed the importance of enduring increases in primary afferent excitability and persistent spontaneous activity in the onset and maintenance of peripherally induced neuropathic pain. Some of this activity results from modulation, increased activity and /or expression of voltage-gated Na+ channels and hyperpolarization-activated cyclic nucleotide–gated (HCN) channels. K+ channels expressed in dorsal root ganglia (DRG) include delayed rectifiers (Kv1.1, 1.2), A-channels (Kv1.4, 3.3, 3.4, 4.1, 4.2, and 4.3), KCNQ or M-channels (Kv7.2, 7.3, 7.4, and 7.5), ATP-sensitive channels (KIR6.2), Ca2+-activated K+ channels (KCa1.1, 2.1, 2.2, 2.3, and 3.1), Na+-activated K+ channels (KCa4.1 and 4.2) and two pore domain leak channels (K2p; TWIK related channels). Function of all K+ channel types is reduced via a multiplicity of processes leading to altered expression and/or post-translational modification. This also increases excitability of DRG cell bodies and nociceptive free nerve endings, alters axonal conduction and increases neurotransmitter release from primary afferent terminals in the spinal dorsal horn. Correlation of these cellular changes with behavioral studies provides almost indisputable evidence for K+ channel dysfunction in the onset and maintenance of neuropathic pain. This idea is underlined by the observation that selective impairment of just one subtype of DRG K+ channel can produce signs of pain in vivo. Whilst it is established that various mediators, including cytokines and growth factors bring about injury-induced changes in DRG function and excitability, evidence presently available points to a seminal role for interleukin 1β (IL-1β) in control of K+ channel function. Despite the current state of knowledge, attempts to target K+ channels for therapeutic pain management have met with limited success. This situation may change with the advent of personalized medicine. Identification of specific sensory abnormalities and genetic profiling of individual patients may predict therapeutic benefit of K+ channel activators.
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Affiliation(s)
- Peter A Smith
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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18
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Stack E, McMurray S, McMurray G, Wade J, Clark M, Young G, Marquette K, Jain S, Kelleher K, Chen T, Lin Q, Bloom L, Lin L, Finlay W, Suzuki R, Cunningham O. In vitro affinity optimization of an anti-BDNF monoclonal antibody translates to improved potency in targeting chronic pain states in vivo. MAbs 2020; 12:1755000. [PMID: 32329655 PMCID: PMC7188400 DOI: 10.1080/19420862.2020.1755000] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The role of brain-derived neurotrophic factor (BDNF) signaling in chronic pain has been well documented. Given the important central role of BDNF in long term plasticity and memory, we sought to engineer a high affinity, peripherally-restricted monoclonal antibody against BDNF to modulate pain. BDNF shares 100% sequence homology across human and rodents; thus, we selected chickens as an alternative immune host for initial antibody generation. Here, we describe the affinity optimization of complementarity-determining region-grafted, chicken-derived R3bH01, an anti-BDNF antibody specifically blocking the TrkB receptor interaction. Antibody optimization led to the identification of B30, which has a > 300-fold improvement in affinity based on BIAcore, an 800-fold improvement in potency in a cell-based pERK assay and demonstrates exquisite selectivity over related neurotrophins. Affinity improvements measured in vitro translated to in vivo pharmacological activity, with B30 demonstrating a 30-fold improvement in potency over parental R3bH01 in a peripheral nerve injury model. We further demonstrate that peripheral BDNF plays a role in maintaining the plasticity of sensory neurons following nerve damage, with B30 reversing neuron hyperexcitability associated with heat and mechanical stimuli in a dose-dependent fashion. In summary, our data demonstrate that effective sequestration of BDNF via a high affinity neutralizing antibody has potential utility in modulating the pathophysiological mechanisms that drive chronic pain states.
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Affiliation(s)
| | | | | | - Jason Wade
- Biomedicine Design, Pfizer, Dublin, Ireland.,Biomedicine Design, Pfizer, Cambridge, US
| | | | | | | | | | | | - Ting Chen
- Biomedicine Design, Pfizer, Cambridge, US
| | | | | | - Laura Lin
- Biomedicine Design, Pfizer, Cambridge, US
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19
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Role of Potassium Ions Quantum Tunneling in the Pathophysiology of Phantom Limb Pain. Brain Sci 2020; 10:brainsci10040241. [PMID: 32325702 PMCID: PMC7226264 DOI: 10.3390/brainsci10040241] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 12/19/2022] Open
Abstract
(1) Background: multiple theories were proposed to explain the phenomenon of phantom limb pain (PLP). Nevertheless, the phenomenon is still shrouded in mystery. The aim of this study is to explore the phenomenon from a new perspective, where quantum tunneling of ions, a promising field in medical practice, might play a major role. (2) Methods: investigators designed a quantum mathematical model based on the Schrödinger equation to examine the probability of potassium ions quantum tunneling through closed membrane potassium channels to the inside of phantom axons, leading to the generation of action potential. (3) Results: the model suggests that the probability of action potential induction at a certain region of the membrane of phantom neurons, when a neuron of the stump area is stimulated over 1 mm2 surface area of the membrane available for tunneling is 1.04 × 10−2. Furthermore, upon considering two probabilities of potassium channelopathies, one that decreased the energy of the barrier by 25% and another one by 50%, the tunneling probability became 1.22 × 10−8 and 3.86 × 10−4, respectively. (4) Conclusion: quantum models of potassium ions can provide a reliable theoretical hypothesis to unveil part of the ambiguity behind PLP.
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20
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Wang L, Tanaka Y, Wang D, Morikawa M, Zhou R, Homma N, Miyamoto Y, Hirokawa N. The Atypical Kinesin KIF26A Facilitates Termination of Nociceptive Responses by Sequestering Focal Adhesion Kinase. Cell Rep 2019; 24:2894-2907. [PMID: 30208315 DOI: 10.1016/j.celrep.2018.05.075] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 04/27/2018] [Accepted: 05/23/2018] [Indexed: 11/18/2022] Open
Abstract
Kinesin superfamily proteins (KIFs) are molecular motors that typically alter the subcellular localization of their cargos. However, the atypical kinesin KIF26A does not serve as a motor but can bind microtubules and affect cellular signaling cascades. Here, we show that KIF26A maintains intracellular calcium homeostasis and negatively regulates nociceptive sensation. Kif26a-/- mice exhibit intense and prolonged nociceptive responses. In their primary sensory neurons, excessive inhibitory phosphorylation of plasma membrane Ca2+ ATPase (PMCA) mediated by focal adhesion kinase (FAK) rendered the Ca transients resistant to termination, and the peripheral axonal outgrowth was significantly enhanced. Upstream, KIF26A is directly associated with a FERM domain of FAK and antagonizes FAK function in integrin-Src family kinase (SFK)-FAK signaling, possibly through steric hindrance and localization to cytoplasmic microtubules.
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Affiliation(s)
- Li Wang
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yosuke Tanaka
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Doudou Wang
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Momo Morikawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ruyun Zhou
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Noriko Homma
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yuki Miyamoto
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Nobutaka Hirokawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Center of Excellence in Genome Medicine Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
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21
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Sandercock DA, Barnett MW, Coe JE, Downing AC, Nirmal AJ, Di Giminiani P, Edwards SA, Freeman TC. Transcriptomics Analysis of Porcine Caudal Dorsal Root Ganglia in Tail Amputated Pigs Shows Long-Term Effects on Many Pain-Associated Genes. Front Vet Sci 2019; 6:314. [PMID: 31620455 PMCID: PMC6760028 DOI: 10.3389/fvets.2019.00314] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 09/03/2019] [Indexed: 12/24/2022] Open
Abstract
Tail amputation by tail docking or as an extreme consequence of tail biting in commercial pig production potentially has serious implications for animal welfare. Tail amputation causes peripheral nerve injury that might be associated with lasting chronic pain. The aim of this study was to investigate the short- and long-term effects of tail amputation in pigs on caudal DRG gene expression at different stages of development, particularly in relation to genes associated with nociception and pain. Microarrays were used to analyse whole DRG transcriptomes from tail amputated and sham-treated pigs 1, 8, and 16 weeks following tail treatment at either 3 or 63 days of age (8 pigs/treatment/age/time after treatment; n = 96). Tail amputation induced marked changes in gene expression (up and down) compared to sham-treated intact controls for all treatment ages and time points after tail treatment. Sustained changes in gene expression in tail amputated pigs were still evident 4 months after tail injury. Gene correlation network analysis revealed two co-expression clusters associated with amputation: Cluster A (759 down-regulated) and Cluster B (273 up-regulated) genes. Gene ontology (GO) enrichment analysis identified 124 genes in Cluster A and 61 genes in Cluster B associated with both “inflammatory pain” and “neuropathic pain.” In Cluster A, gene family members of ion channels e.g., voltage-gated potassium channels (VGPC) and receptors e.g., GABA receptors, were significantly down-regulated compared to shams, both of which are linked to increased peripheral nerve excitability after axotomy. Up-regulated gene families in Cluster B were linked to transcriptional regulation, inflammation, tissue remodeling, and regulatory neuropeptide activity. These findings, demonstrate that tail amputation causes sustained transcriptomic expression changes in caudal DRG cells involved in inflammatory and neuropathic pain pathways.
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Affiliation(s)
- Dale A Sandercock
- Animal and Veterinary Science Research Group, Scotland's Rural College, Roslin Institute Building, Edinburgh, United Kingdom
| | - Mark W Barnett
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Jennifer E Coe
- Animal and Veterinary Science Research Group, Scotland's Rural College, Roslin Institute Building, Edinburgh, United Kingdom
| | - Alison C Downing
- Edinburgh Genomics, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ajit J Nirmal
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Pierpaolo Di Giminiani
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Sandra A Edwards
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Tom C Freeman
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
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22
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Ciotu CI, Tsantoulas C, Meents J, Lampert A, McMahon SB, Ludwig A, Fischer MJM. Noncanonical Ion Channel Behaviour in Pain. Int J Mol Sci 2019; 20:E4572. [PMID: 31540178 PMCID: PMC6770626 DOI: 10.3390/ijms20184572] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 12/19/2022] Open
Abstract
Ion channels contribute fundamental properties to cell membranes. Although highly diverse in conductivity, structure, location, and function, many of them can be regulated by common mechanisms, such as voltage or (de-)phosphorylation. Primarily considering ion channels involved in the nociceptive system, this review covers more novel and less known features. Accordingly, we outline noncanonical operation of voltage-gated sodium, potassium, transient receptor potential (TRP), and hyperpolarization-activated cyclic nucleotide (HCN)-gated channels. Noncanonical features discussed include properties as a memory for prior voltage and chemical exposure, alternative ion conduction pathways, cluster formation, and silent subunits. Complementary to this main focus, the intention is also to transfer knowledge between fields, which become inevitably more separate due to their size.
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Affiliation(s)
- Cosmin I Ciotu
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | | | - Jannis Meents
- Institute of Physiology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Angelika Lampert
- Institute of Physiology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Stephen B McMahon
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UR, UK
| | - Andreas Ludwig
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Michael J M Fischer
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.
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23
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Zakaria ZA, Abdul Rahim MH, Roosli RAJ, Mohd Sani MH, Marmaya NH, Omar MH, Teh LK, Salleh MZ. Antinociceptive Activity of Petroleum Ether Fraction of Clinacanthus nutans Leaves Methanolic Extract: Roles of Nonopioid Pain Modulatory Systems and Potassium Channels. BIOMED RESEARCH INTERNATIONAL 2019; 2019:6593125. [PMID: 31467905 PMCID: PMC6699298 DOI: 10.1155/2019/6593125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 05/22/2019] [Accepted: 07/09/2019] [Indexed: 12/13/2022]
Abstract
Methanolic extract of Clinacanthus nutans Lindau leaves (MECN) has been reported to exert antinociceptive activity. The present study aimed to elucidate the possible antinociceptive mechanisms of a lipid-soluble fraction of MECN, which was obtained after sequential extraction in petroleum ether. The petroleum ether fraction of C. nutans (PECN), administered orally to mice, was (i) subjected to capsaicin-, glutamate-, phorbol 12-myristate 13-acetate-, bradykinin-induced nociception model; (ii) prechallenged (intraperitoneal (i.p.)) with 0.15 mg/kg yohimbine, 1 mg/kg pindolol, 3 mg/kg caffeine, 0.2 mg/kg haloperidol, or 10 mg/kg atropine, which were the respective antagonist of α 2-adrenergic, β-adrenergic, adenosinergic, dopaminergic, or muscarinic receptors; and (iii) prechallenged (i.p.) with 10 mg/kg glibenclamide, 0.04 mg/kg apamin, 0.02 mg/kg charybdotoxin, or 4 mg/kg tetraethylammonium chloride, which were the respective inhibitor of ATP sensitive-, small conductance Ca2+-activated-, large conductance Ca2+-activated-, or nonselective voltage-activated-K+ channel. Results obtained demonstrated that PECN (100, 250, and 500 mg/kg) significantly (P<0.05) inhibited all models of nociception described earlier. The antinociceptive activity of 500 mg/kg PECN was significantly (P<0.05) attenuated when prechallenged with all antagonists or K+ channel blockers. However, only pretreatment with apamin and charybdotoxin caused full inhibition of PECN-induced antinociception. The rest of the K+ channel blockers and all antagonists caused only partial inhibition of PECN antinociception, respectively. Analyses on PECN's phytoconstituents revealed the presence of antinociceptive-bearing bioactive compounds of volatile (i.e., derivatives of γ-tocopherol, α-tocopherol, and lupeol) and nonvolatile (i.e., cinnamic acid) nature. In conclusion, PECN exerts a non-opioid-mediated antinociceptive activity involving mainly activation of adenosinergic and cholinergic receptors or small- and large-conductance Ca2+-activated-K+ channels.
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Affiliation(s)
- Zainul Amiruddin Zakaria
- Department of Biomedical Science, Faculty of Medicine and Health Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
- Integrative Pharmacogenomics Institute (iPROMISE), Level 7, FF3, Faculty of Pharmacy, Universiti Teknologi MARA, Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor, Malaysia
| | - Mohammad Hafiz Abdul Rahim
- Department of Biomedical Science, Faculty of Medicine and Health Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Rushduddin Al Jufri Roosli
- Department of Biomedical Science, Faculty of Medicine and Health Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Mohd Hijaz Mohd Sani
- Department of Biomedical Sciences and Therapeutics, Faculty of Medicine and Health Science, Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Malaysia
| | - Najihah Hanisah Marmaya
- Faculty of Business and Management, Universiti Teknologi MARA, Melaka Campus, 75300, Melaka, Malaysia
| | - Maizatul Hasyima Omar
- Phytochemistry Unit, Herbal Medicine Research Centre, Institute for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia
| | - Lay Kek Teh
- Integrative Pharmacogenomics Institute (iPROMISE), Level 7, FF3, Faculty of Pharmacy, Universiti Teknologi MARA, Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor, Malaysia
| | - Mohd. Zaki Salleh
- Integrative Pharmacogenomics Institute (iPROMISE), Level 7, FF3, Faculty of Pharmacy, Universiti Teknologi MARA, Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor, Malaysia
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24
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Chidambaran V, Gang Y, Pilipenko V, Ashton M, Ding L. Systematic Review and Meta-Analysis of Genetic Risk of Developing Chronic Postsurgical Pain. THE JOURNAL OF PAIN 2019; 21:2-24. [PMID: 31129315 DOI: 10.1016/j.jpain.2019.05.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/06/2019] [Accepted: 05/20/2019] [Indexed: 02/08/2023]
Abstract
Chronic postsurgical pain (CPSP) is a significant detriment to postsurgical recovery and a risk factor for prolonged opioid use. Emerging evidence suggests the estimated heritability for chronic pain is 45% and that genetic factors partially explain individual susceptibility to CPSP. The aim of this study was to systematically review, assess quality, and summarize the studies in humans that have investigated genetic factors associated with CPSP. We also conducted a meta-analysis to derive a single effect size for evaluable genetic associations with CPSP. Our comprehensive literature search included review of 21 full-text articles evaluating variants of 69 genes for association with CPSP. We found significant gene variant associations reported for variants/haplotypes of 26 genes involved in neurotransmission, pain signaling, immune responses and neuroactive ligand-receptor interaction, with CPSP. Six variants of 5 genes (COMT: rs4680 and rs6269, OPRM1: rs1799971, GCH1: rs3783641, KCNS1: rs734784 and TNFA: rs1800629), were evaluated by more than one study and were included in the meta-analysis. At rs734784 (A>G) of KCNS1, presence of G allele marginally increased risk of CPSP (Additive genetic model; Odds ratio: 1.511; 95% CI 1-2.284; P value: .050), while the other variants did not withstand meta-analyses criteria. Our findings demonstrate the role of genetic factors with different functions in CPSP, and also emphasize that single genetic factors have small effect sizes in explaining complex conditions like CPSP. Heterogeneity in surgical cohorts, population structure, and outcome definitions, as well as small number of available studies evaluating same variants, limit the meta-analysis. There is a need for large-scale, homogenous, replication studies to validate candidate genes, and understand the underlying biological networks underpinning CPSP. PERSPECTIVE: Our systematic review comprehensively describes 21 studies evaluating genetic association with CPSP, and limitations thereof. A meta-analysis of 6 variants (5 genes) found marginally increased risk for CPSP associated with rs734784 A>G of the potassium voltage-gated channel gene (KCNS1). Understanding genetic predisposition for CPSP will enable prediction and personalized management.
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Affiliation(s)
- Vidya Chidambaran
- Department of Anesthesiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio.
| | - Yang Gang
- Division of Biostatistics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Mathematical Sciences, University of Cincinnati, Cincinnati, Ohio
| | - Valentina Pilipenko
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Maria Ashton
- Department of Anesthesiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Lili Ding
- Division of Biostatistics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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25
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Abstract
Voltage-gated potassium (Kv) channels are increasingly recognised as key regulators of nociceptive excitability. Kcns1 is one of the first potassium channels to be associated with neuronal hyperexcitability and mechanical sensitivity in the rat, as well as pain intensity and risk of developing chronic pain in humans. Here, we show that in mice, Kcns1 is predominantly expressed in the cell body and axons of myelinated sensory neurons positive for neurofilament-200, including Aδ-fiber nociceptors and low-threshold Aβ mechanoreceptors. In the spinal cord, Kcns1 was detected in laminae III to V of the dorsal horn where most sensory A fibers terminate, as well as large motoneurons of the ventral horn. To investigate Kcns1 function specifically in the periphery, we generated transgenic mice in which the gene is deleted in all sensory neurons but retained in the central nervous system. Kcns1 ablation resulted in a modest increase in basal mechanical pain, with no change in thermal pain processing. After neuropathic injury, Kcns1 KO mice exhibited exaggerated mechanical pain responses and hypersensitivity to both noxious and innocuous cold, consistent with increased A-fiber activity. Interestingly, Kcns1 deletion also improved locomotor performance in the rotarod test, indicative of augmented proprioceptive signalling. Our results suggest that restoring Kcns1 function in the periphery may be of some use in ameliorating mechanical and cold pain in chronic states.
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26
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Li Y, Zhang L, Wu Y, Zheng Q, Chen M, Qian Z, Wei C, Han J, Liu Z, Ren W, Liu Y. Cannabinoids-induced peripheral analgesia depends on activation of BK channels. Brain Res 2019; 1711:23-28. [PMID: 30615887 DOI: 10.1016/j.brainres.2019.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 12/11/2018] [Accepted: 01/03/2019] [Indexed: 12/14/2022]
Abstract
The endogenous cannabinoid system is involved in the physiological inhibitory control of pain and is of particular interest for the development of therapeutic approaches for pain management. Selective activation of the peripheral CB1 cannabinoid receptor has been shown to suppress the heightened firing of primary afferents, which is the peripheral mechanism underlying neuropathic pain after nerve injury. However, the mechanism underlying this effect of CB1 receptor remains unclear. The large-conductance calcium-activated potassium (BK) channels have been reported to participate in anticonvulsant and vasorelaxant effects of cannabinoids. We asked whether BK channels participate in cannabinoids-induced analgesia and firing-suppressing effects in primary afferents after nerve injury. Here, using mice with chronic constriction injury (CCI)-induced neuropathic pain, antinociception action and firing-suppressing effect of HU210 were measured before and after BK channel blocker application. We found that local peripheral application of HU210 alleviated CCI-induced pain behavior and suppressed the heightened firing of injured fibers. Co-administration of IBTX with HU210 significantly reversed the analgesia and the firing-suppressing effect of HU210. This result indicated that the peripheral analgesic effects of cannabinoids depends on activation of BK channels.
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Affiliation(s)
- Yongfeng Li
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an 710062, China
| | - Leili Zhang
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an 710062, China
| | - Yuwei Wu
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an 710062, China
| | - Qiaohua Zheng
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an 710062, China
| | - Mengjiao Chen
- School of Physics & Information Technology, Shaanxi Normal University, 620 West Chang'an Avenue, Xi'an 710119, China
| | - Zhaoqiang Qian
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an 710062, China
| | - Chunling Wei
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an 710062, China
| | - Jing Han
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an 710062, China
| | - Zhiqiang Liu
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an 710062, China
| | - Wei Ren
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an 710062, China
| | - Yihui Liu
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an 710062, China.
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Guha D, Shamji MF. The Dorsal Root Ganglion in the Pathogenesis of Chronic Neuropathic Pain. Neurosurgery 2018; 63 Suppl 1:118-126. [PMID: 27399376 DOI: 10.1227/neu.0000000000001255] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
| | - Mohammed F Shamji
- Department of Surgery and.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.,Division of Neurosurgery, Toronto Western Hospital, Toronto, Ontario, Canada
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Hathway GJ, Murphy E, Lloyd J, Greenspon C, Hulse RP. Cancer Chemotherapy in Early Life Significantly Alters the Maturation of Pain Processing. Neuroscience 2018; 387:214-229. [PMID: 29196027 PMCID: PMC6150930 DOI: 10.1016/j.neuroscience.2017.11.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 10/24/2017] [Accepted: 11/16/2017] [Indexed: 12/22/2022]
Abstract
Advances in pediatric cancer treatment have led to a ten year survival rate greater than 75%. Platinum-based chemotherapies (e.g. cisplatin) induce peripheral sensory neuropathy in adult and pediatric cancer patients. The period from birth through to adulthood represents a period of maturation within nociceptive systems. Here we investigated how cisplatin impacts upon postnatal maturation of nociceptive systems. Neonatal Wistar rats (Postnatal day (P) 7) were injected (i.p.) daily with either vehicle (PBS) or cisplatin (1mg/kg) for five consecutive days. Neither group developed mechanical or thermal hypersensitivity immediately during or after treatment. At P22 the cisplatin group developed mechanical (P < 0.05) and thermal (P < 0.0001) hypersensitivity versus vehicle group. Total DRG or dorsal horn neuronal number did not differ at P45, however there was an increase in intraepidermal nerve fiber density in cisplatin-treated animals at this age. The percentage of IB4+ve, CGRP+ve and NF200+ve DRG neurons was not different between groups at P45. There was an increase in TrkA+ve DRG neurons in the cisplatin group at P45, in addition to increased TrkA, NF200 and vGLUT2 immunoreactivity in the lumbar dorsal horn versus controls. These data highlight the impact pediatric cancer chemotherapy has upon the maturation of pain pathways and later life pain experience.
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Affiliation(s)
- G J Hathway
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom.
| | - Emily Murphy
- Cancer Biology, School of Medicine, University of Nottingham, Nottingham NG7 2UH, United Kingdom
| | - Joseph Lloyd
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
| | - Charles Greenspon
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
| | - R P Hulse
- Cancer Biology, School of Medicine, University of Nottingham, Nottingham NG7 2UH, United Kingdom; School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, United Kingdom.
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29
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Bates DO, Beazley-Long N, Benest AV, Ye X, Ved N, Hulse RP, Barratt S, Machado MJ, Donaldson LF, Harper SJ, Peiris-Pages M, Tortonese DJ, Oltean S, Foster RR. Physiological Role of Vascular Endothelial Growth Factors as Homeostatic Regulators. Compr Physiol 2018; 8:955-979. [PMID: 29978898 DOI: 10.1002/cphy.c170015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The vascular endothelial growth factor (VEGF) family of proteins are key regulators of physiological systems. Originally linked with endothelial function, they have since become understood to be principal regulators of multiple tissues, both through their actions on vascular cells, but also through direct actions on other tissue types, including epithelial cells, neurons, and the immune system. The complexity of the five members of the gene family in terms of their different splice isoforms, differential translation, and specific localizations have enabled tissues to use these potent signaling molecules to control how they function to maintain their environment. This homeostatic function of VEGFs has been less intensely studied than their involvement in disease processes, development, and reproduction, but they still play a substantial and significant role in healthy control of blood volume and pressure, interstitial volume and drainage, renal and lung function, immunity, and signal processing in the peripheral and central nervous system. The widespread expression of VEGFs in healthy adult tissues, and the disturbances seen when VEGF signaling is inhibited support this view of the proteins as endogenous regulators of normal physiological function. This review summarizes the evidence and recent breakthroughs in understanding of the physiology that is regulated by VEGF, with emphasis on the role they play in maintaining homeostasis. © 2017 American Physiological Society. Compr Physiol 8:955-979, 2018.
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Affiliation(s)
- David O Bates
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | | | - Andrew V Benest
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | - Xi Ye
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Nikita Ved
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Richard P Hulse
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | - Shaney Barratt
- Academic Respiratory Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Maria J Machado
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | - Lucy F Donaldson
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Steven J Harper
- School of Physiology, Pharmacology & Neuroscience, Medical School, University of Bristol, Bristol, United Kingdom
| | - Maria Peiris-Pages
- Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Domingo J Tortonese
- Centre for Comparative and Clinical Anatomy, University of Bristol, Bristol, United Kingdom
| | - Sebastian Oltean
- Institute of Biomedical & Clinical Sciences, University of Exeter Medical School, Exeter, United Kingdom
| | - Rebecca R Foster
- Bristol Renal, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
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30
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Collins KL, Russell HG, Schumacher PJ, Robinson-Freeman KE, O'Conor EC, Gibney KD, Yambem O, Dykes RW, Waters RS, Tsao JW. A review of current theories and treatments for phantom limb pain. J Clin Invest 2018; 128:2168-2176. [PMID: 29856366 DOI: 10.1172/jci94003] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Following amputation, most amputees still report feeling the missing limb and often describe these feelings as excruciatingly painful. Phantom limb sensations (PLS) are useful while controlling a prosthesis; however, phantom limb pain (PLP) is a debilitating condition that drastically hinders quality of life. Although such experiences have been reported since the early 16th century, the etiology remains unknown. Debate continues regarding the roles of the central and peripheral nervous systems. Currently, the most posited mechanistic theories rely on neuronal network reorganization; however, greater consideration should be given to the role of the dorsal root ganglion within the peripheral nervous system. This Review provides an overview of the proposed mechanistic theories as well as an overview of various treatments for PLP.
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Affiliation(s)
| | - Hannah G Russell
- Department of Neurology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Patrick J Schumacher
- Department of Neurology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | | | - Ellen C O'Conor
- Department of Neurology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Kyla D Gibney
- Department of Neurology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Olivia Yambem
- Department of Neurology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Robert W Dykes
- School of Physical and Occupational Therapy, McGill University, Montreal, Quebec, Canada
| | | | - Jack W Tsao
- Department of Neurology, University of Tennessee Health Science Center, Memphis, Tennessee, USA.,Department of Neurology, Memphis Veterans Affairs Medical Center, Memphis, Tennessee, USA.,Children's Foundation Research Institute, Le Bonheur Children's Hospital, Memphis, Tennessee, USA
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31
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Takkala P, Prescott SA. Using dynamic clamp to quantify pathological changes in the excitability of primary somatosensory neurons. J Physiol 2018; 596:2209-2227. [PMID: 29601637 PMCID: PMC5983269 DOI: 10.1113/jp275580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/21/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Primary somatosensory neurons normally respond to somatic depolarization with transient spiking but can switch to repetitive spiking under pathological conditions. This switch in spiking pattern reflects a qualitative change in spike initiation dynamics and contributes to the hyperexcitability associated with chronic pain. Neurons can be converted to repetitive spiking by adding a virtual conductance using dynamic clamp. By titrating the conductance to determine how much must be added to cause repetitive spiking, we found that small cells are more susceptible to switching (i.e. required less added conductance) than medium-large cells. By measuring how much less conductance is required to cause repetitive spiking when dynamic clamp was combined with other pathomimetic manipulations (e.g. application of inflammatory mediators), we measured how much each manipulation facilitated repetitive spiking. Our results suggest that many pathological factors facilitate repetitive spiking but that the switch to repetitive spiking requires the cumulative effect of many co-occurring factors. ABSTRACT Primary somatosensory neurons become hyperexcitable in many chronic pain conditions. Hyperexcitability can include a switch from transient to repetitive spiking during sustained somatic depolarization. This switch results from diverse pathological processes that impact ion channel expression or function. Because multiple pathological processes co-occur, isolating how much each contributes to switching the spiking pattern is difficult. Our approach to this challenge involves adding a virtual sodium conductance via dynamic clamp. The magnitude of that conductance was titrated to determine the minimum required to enable rheobasic stimulation to evoke repetitive spiking. The minimum required conductance, termed g¯ Na ∗, was re-measured before and during manipulations designed to model various pathological processes in vitro. The reduction in g¯ Na ∗ caused by each pathomimetic manipulation reflects how much the modelled process contributes to switching the spiking pattern. We found that elevating extracellular potassium or applying inflammatory mediators reduced g¯ Na ∗ whereas direct hyperpolarization had no effect. Inflammatory mediators reduced g¯ Na ∗ more in medium-large (>30 μm diameter) neurons than in small (⩽30 μm diameter) neurons, but had equivalent effects in cutaneous and muscle afferents. The repetitive spiking induced by dynamic clamp was also found to differ between small and medium-large neurons, thus revealing latent differences in adaptation. Our study demonstrates a novel way to determine to what extent individual pathological factors facilitate repetitive spiking. Our results suggest that most factors facilitate but do not cause repetitive spiking on their own, and, therefore, that a switch to repetitive spiking results from the cumulative effect of many co-occurring factors.
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Affiliation(s)
- Petri Takkala
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 0A4.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
| | - Steven A Prescott
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 0A4.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada, M5S 1A8.,Department of Physiology and Institute of Biomaterials and Biomedical Engineering, University of Toronto, Ontario, Canada, M5S 1A8
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33
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Megat S, Price TJ. Therapeutic opportunities for pain medicines via targeting of specific translation signaling mechanisms. NEUROBIOLOGY OF PAIN 2018; 4:8-19. [PMID: 30211342 PMCID: PMC6130820 DOI: 10.1016/j.ynpai.2018.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A common underlying cause of chronic pain is a phenotypic change in nociceptors in the peripheral nervous system. Translation regulation signaling pathways control gene expression changes that drive chronic pain. We focus on developments in pharmacology around translation regulation signaling that may yield new pain therapeutics.
As the population of the world ages and as more and more people survive diseases that used to be primary causes of mortality, the incidence of severe chronic pain in most of the world has risen dramatically. This type of pain is very difficult to treat and the opioid overdose epidemic that has become a leading cause of death in the United States and other parts of the world highlights the urgent need to develop new pain therapeutics. A common underlying cause of severe chronic pain is a phenotypic change in pain-sensing neurons in the peripheral nervous system called nociceptors. These neurons play a vital role in detecting potentially injurious stimuli, but when these neurons start to detect very low levels of inflammatory meditators or become spontaneously active, they send spurious pain signals to the brain that are significant drivers of chronic pain. An important question is what drives this phenotypic shift in nociceptors from quiescence under most conditions to sensitization to a broad variety of stimuli and spontaneous activity. The goal of this review is to discuss the critical role that specific translation regulation signaling pathways play in controlling gene expression changes that drive nociceptor sensitization and may underlie the development of spontaneous activity. The focus will be on advances in technologies that allow for identification of such targets and on developments in pharmacology around translation regulation signaling that may yield new pain therapeutics. A key advantage of pharmacological manipulation of these signaling events is that they may reverse phenotypic shifts in nociceptors that drive chronic pain thereby creating the first generation of disease modifying drugs for chronic pain.
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Affiliation(s)
- Salim Megat
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, USA
| | - Theodore J Price
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, USA
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34
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Latremoliere A, Costigan M. Combining Human and Rodent Genetics to Identify New Analgesics. Neurosci Bull 2018; 34:143-155. [PMID: 28667479 PMCID: PMC5799129 DOI: 10.1007/s12264-017-0152-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 06/01/2017] [Indexed: 12/26/2022] Open
Abstract
Most attempts at rational development of new analgesics have failed, in part because chronic pain involves multiple processes that remain poorly understood. To improve translational success, one strategy is to select novel targets for which there is proof of clinical relevance, either genetically through heritable traits, or pharmacologically. Such an approach by definition yields targets with high clinical validity. The biology of these targets can be elucidated in animal models before returning to the patients with a refined therapeutic. For optimal treatment, having biomarkers of drug action available is also a plus. Here we describe a case study in rational drug design: the use of controlled inhibition of peripheral tetrahydrobiopterin (BH4) synthesis to reduce abnormal chronic pain states without altering nociceptive-protective pain. Initially identified in a population of patients with low back pain, the association between BH4 production and chronic pain has been confirmed in more than 12 independent cohorts, through a common haplotype (present in 25% of Caucasians) of the rate-limiting enzyme for BH4 synthesis, GTP cyclohydrolase 1 (GCH1). Genetic tools in mice have demonstrated that both injured sensory neurons and activated macrophages engage increased BH4 synthesis to cause chronic pain. GCH1 is an obligate enzyme for de novo BH4 production. Therefore, inhibiting GCH1 activity eliminates all BH4 production, affecting the synthesis of multiple neurotransmitters and signaling molecules and interfering with physiological function. In contrast, targeting the last enzyme of the BH4 synthesis pathway, sepiapterin reductase (SPR), allows reduction of pathological BH4 production without completely blocking physiological BH4 synthesis. Systemic SPR inhibition in mice has not revealed any safety concerns to date, and available genetic and pharmacologic data suggest similar responses in humans. Finally, because it is present in vivo only when SPR is inhibited, sepiapterin serves as a reliable biomarker of target engagement, allowing potential quantification of drug efficacy. The emerging development of therapeutics that target BH4 synthesis to treat chronic pain illustrates the power of combining human and mouse genetics: human genetic studies for clinical selection of relevant targets, coupled with causality studies in mice, allowing the rational engineering of new analgesics.
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Affiliation(s)
- Alban Latremoliere
- Kirby Neurobiology Center, Boston Children's Hospital and Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA.
| | - Michael Costigan
- Kirby Neurobiology Center, Boston Children's Hospital and Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, 02115, USA.
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35
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Korczeniewska OA, Husain S, Khan J, Eliav E, Soteropoulos P, Benoliel R. Differential gene expression in trigeminal ganglia of male and female rats following chronic constriction of the infraorbital nerve. Eur J Pain 2018; 22:875-888. [PMID: 29350446 DOI: 10.1002/ejp.1174] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND The mechanisms underlying sex-based differences in pain and analgesia are poorly understood. In this study, we investigated gene expression changes in trigeminal ganglia (TG) of male and female rats exposed to infraorbital nerve chronic constriction injury (IoN-CCI). METHODS Somatosensory assessments were performed prior to IoN-CCI and at selected time points postsurgery. Selected gene expression changes were examined with real-time quantitative polymerase chain reaction (RT-PCR) in ipsilateral TG at 21 days postsurgery. RESULTS Rats exposed to IoN-CCI developed significant mechanical allodynia and hyperalgesia on days 19 and 21 postsurgery. During this period, females developed significantly more allodynia but not hyperalgesia compared to males. At 21 days postsurgery, expression levels of 44 of the 84 investigated pain-related genes in ipsilateral TG were significantly regulated relative to naïve rats in either sex. Csf1 and Cx3cr1 were up-regulated in both sexes, but the magnitude of regulation was significantly higher in females (p = 0.02 and p = 0.001, respectively). Htr1a and Scn9a were down-regulated in both sexes, but the down-regulation was significantly more pronounced in males (p = 0.04 and p = 0.02, respectively). Additionally, Cck, Il1a, Pla2g1b and Tnf genes were significantly regulated in females but not in males, and Chrna4 gene was significantly down-regulated in males but not in females. CONCLUSIONS Our findings suggest sex-dependent gene regulation in response to nerve injury, which may contribute to sex dimorphism of trigeminal neuropathic pain. Further studies are needed to establish gene expression changes over time and correlate these with hormonal and other physiological parameters in male and female. SIGNIFICANCE We present novel sex-specific transcriptional regulation in trigeminal ganglia that may contribute to male-/female-based differences in trigeminal neuropathic pain. These findings are expected to open new research horizons, particularly in male versus female targeted therapeutic regimens.
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Affiliation(s)
- O A Korczeniewska
- Department of Diagnostic Sciences, Rutgers School of Dental Medicine, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - S Husain
- The Genomics Center, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - J Khan
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, NY, USA
| | - E Eliav
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, NY, USA
| | - P Soteropoulos
- The Genomics Center, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - R Benoliel
- Department of Diagnostic Sciences, Rutgers School of Dental Medicine, Rutgers, The State University of New Jersey, Newark, NJ, USA
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36
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Abstract
Acute and chronic pain complaints, although common, are generally poorly served by existing therapies. This unmet clinical need reflects a failure to develop novel classes of analgesics with superior efficacy, diminished adverse effects and a lower abuse liability than those currently available. Reasons for this include the heterogeneity of clinical pain conditions, the complexity and diversity of underlying pathophysiological mechanisms, and the unreliability of some preclinical pain models. However, recent advances in our understanding of the neurobiology of pain are beginning to offer opportunities for developing novel therapeutic strategies and revisiting existing targets, including modulating ion channels, enzymes and G-protein-coupled receptors.
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37
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Zhu M, Sun X, Chen X, Xiao H, Duan M, Xu J. Impact of gabapentin on neuronal high voltage-activated Ca 2+ channel properties of injured-side axotomized and adjacent uninjured dorsal root ganglions in a rat model of spinal nerve ligation. Exp Ther Med 2017; 13:851-860. [PMID: 28450909 PMCID: PMC5403705 DOI: 10.3892/etm.2017.4071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 09/27/2016] [Indexed: 11/17/2022] Open
Abstract
The density and properties of ion channels in the injured axon and dorsal root ganglion (DRG) neuronal soma membrane change following nerve injury, which may result in the development of neuropathic pain. Gabapentin (GBP) is a drug for the first-line treatment of neuropathic pain. One of its therapeutic targets is the voltage-activated calcium channel (VACC). In the present study, the whole-cell patch clamp technique was used to examine the changes of high voltage-activated Ca2+ (HVA-Ca2+) channels in DRG neurons from sham and neuropathic rats in the absence and presence of GBP. The results demonstrated a reduction in peak current density and the ‘window current’ between activation and inactivation in adjacent and axotomized neurons from rats that had undergone L5 spinal nerve ligation, thus attenuating the total inward Ca2+ current. Following the use of the specific channel blockers nifedipine, ω-conotoxin MVIIC and ω-conotoxin MVIIA, increased HVA-Ca2+ channels as well as an increased proportion of N-type Ca2+ currents were observed in axotomized neurons. GBP inhibited HVA calcium channel currents in a dose-dependent manner. The activation and steady-state inactivation curves for HVA channels were shifted in a hyperpolarizing direction by 100 µmol/l GBP. Following the application of GBP, a reduction in the ‘window current’ was observed in control and axotomized neurons, whereas the ‘window current’ was unchanged in adjacent neurons. This indicates that the inhibitory effects of GBP may be dependent on particular neuropathological or inflammatory conditions. The proportion of N-type Ca2+ currents and sensitivity to GBP were increased in axotomized neurons, which indicated the involvement of N-type Ca2+ currents in the inhibitory effect of GBP.
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Affiliation(s)
- Minmin Zhu
- Department of Anaesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, P.R. China.,Department of Anaesthesiology, Wuxi Second Hospital, Nanjing Medical University, Wuxi, Jiangsu 214002, P.R. China
| | - Xiaodi Sun
- Department of Anaesthesiology, First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210002, P.R. China
| | - Xiaodong Chen
- Department of Anaesthesiology, First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210002, P.R. China
| | - Hang Xiao
- Department of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Manlin Duan
- Department of Anaesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, P.R. China
| | - Jianguo Xu
- Department of Anaesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, P.R. China
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38
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HCN2 ion channels: basic science opens up possibilities for therapeutic intervention in neuropathic pain. Biochem J 2016; 473:2717-36. [DOI: 10.1042/bcj20160287] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/18/2016] [Indexed: 01/22/2023]
Abstract
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.
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39
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Hulse RP, Drake RAR, Bates DO, Donaldson LF. The control of alternative splicing by SRSF1 in myelinated afferents contributes to the development of neuropathic pain. Neurobiol Dis 2016; 96:186-200. [PMID: 27616424 PMCID: PMC5113660 DOI: 10.1016/j.nbd.2016.09.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/24/2016] [Accepted: 09/06/2016] [Indexed: 02/07/2023] Open
Abstract
Neuropathic pain results from neuroplasticity in nociceptive neuronal networks. Here we demonstrate that control of alternative pre-mRNA splicing, through the splice factor serine-arginine splice factor 1 (SRSF1), is integral to the processing of nociceptive information in the spinal cord. Neuropathic pain develops following a partial saphenous nerve ligation injury, at which time SRSF1 is activated in damaged myelinated primary afferent neurons, with minimal found in small diameter (IB4 positive) dorsal root ganglia neurons. Serine arginine protein kinase 1 (SRPK1) is the principal route of SRSF1 activation. Spinal SRPK1 inhibition attenuated SRSF1 activity, abolished neuropathic pain behaviors and suppressed central sensitization. SRSF1 was principally expressed in large diameter myelinated (NF200-rich) dorsal root ganglia sensory neurons and their excitatory central terminals (vGLUT1+ve) within the dorsal horn of the lumbar spinal cord. Expression of pro-nociceptive VEGF-Axxxa within the spinal cord was increased after nerve injury, and this was prevented by SRPK1 inhibition. Additionally, expression of anti-nociceptive VEGF-Axxxb isoforms was elevated, and this was associated with reduced neuropathic pain behaviors. Inhibition of VEGF receptor-2 signaling in the spinal cord attenuated behavioral nociceptive responses to mechanical, heat and formalin stimuli, indicating that spinal VEGF receptor-2 activation has potent pro-nociceptive actions. Furthermore, intrathecal VEGF-A165a resulted in mechanical and heat hyperalgesia, whereas the sister inhibitory isoform VEGF-A165b resulted in anti-nociception. These results support a role for myelinated fiber pathways, and alternative pre-mRNA splicing of factors such as VEGF-A in the spinal processing of neuropathic pain. They also indicate that targeting pre-mRNA splicing at the spinal level could lead to a novel target for analgesic development.
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Affiliation(s)
- Richard P Hulse
- Cancer Biology, School of Medicine, University of Nottingham, Nottingham, NG7 7UH, United Kingdom; School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom.
| | - Robert A R Drake
- School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - David O Bates
- Cancer Biology, School of Medicine, University of Nottingham, Nottingham, NG7 7UH, United Kingdom; School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Lucy F Donaldson
- School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom; School of Life Sciences and Arthritis Research UK Pain Centre, University of Nottingham, Nottingham NG7 7UH, United Kingdom.
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40
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Abstract
UNLABELLED DNA 5-hydroxylmethylcytosine (5hmC) catalyzed by ten-eleven translocation methylcytosine dioxygenase (TET) occurs abundantly in neurons of mammals. However, the in vivo causal link between TET dysregulation and nociceptive modulation has not been established. Here, we found that spinal TET1 and TET3 were significantly increased in the model of formalin-induced acute inflammatory pain, which was accompanied with the augment of genome-wide 5hmC content in spinal cord. Knockdown of spinal TET1 or TET3 alleviated the formalin-induced nociceptive behavior and overexpression of spinal TET1 or TET3 in naive mice produced pain-like behavior as evidenced by decreased thermal pain threshold. Furthermore, we found that TET1 or TET3 regulated the nociceptive behavior by targeting microRNA-365-3p (miR-365-3p). Formalin increased 5hmC in the miR-365-3p promoter, which was inhibited by knockdown of TET1 or TET3 and mimicked by overexpression of TET1 or TET3 in naive mice. Nociceptive behavior induced by formalin or overexpression of spinal TET1 or TET3 could be prevented by downregulation of miR-365-3p, and mimicked by overexpression of spinal miR-365-3p. Finally, we demonstrated that a potassium channel, voltage-gated eag-related subfamily H member 2 (Kcnh2), validated as a target of miR-365-3p, played a critical role in nociceptive modulation by spinal TET or miR-365-3p. Together, we concluded that TET-mediated hydroxymethylation of miR-365-3p regulates nociceptive behavior via Kcnh2. SIGNIFICANCE STATEMENT Mounting evidence indicates that epigenetic modifications in the nociceptive pathway contribute to pain processes and analgesia response. Here, we found that the increase of 5hmC content mediated by TET1 or TET3 in miR-365-3p promoter in the spinal cord is involved in nociceptive modulation through targeting a potassium channel, Kcnh2. Our study reveals a new epigenetic mechanism underlying nociceptive information processing, which may be a novel target for development of antinociceptive drugs.
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Yin K, Baillie GJ, Vetter I. Neuronal cell lines as model dorsal root ganglion neurons: A transcriptomic comparison. Mol Pain 2016; 12:1744806916646111. [PMID: 27130590 PMCID: PMC4956150 DOI: 10.1177/1744806916646111] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 02/24/2016] [Accepted: 03/16/2016] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Dorsal root ganglion neuron-derived immortal cell lines including ND7/23 and F-11 cells have been used extensively as in vitro model systems of native peripheral sensory neurons. However, while it is clear that some sensory neuron-specific receptors and ion channels are present in these cell lines, a systematic comparison of the molecular targets expressed by these cell lines with those expressed in intact peripheral neurons is lacking. RESULTS In this study, we examined the expression of RNA transcripts in the human neuroblastoma-derived cell line, SH-SY5Y, and two dorsal root ganglion hybridoma cell lines, F-11 and ND7/23, using Illumina next-generation sequencing, and compared the results with native whole murine dorsal root ganglions. The gene expression profiles of these three cell lines did not resemble any specific defined dorsal root ganglion subclass. The cell lines lacked many markers for nociceptive sensory neurons, such as the Transient receptor potential V1 gene, but expressed markers for both myelinated and unmyelinated neurons. Global gene ontology analysis on whole dorsal root ganglions and cell lines showed similar enrichment of biological process terms across all samples. CONCLUSIONS This paper provides insights into the receptor repertoire expressed in common dorsal root ganglion neuron-derived cell lines compared with whole murine dorsal root ganglions, and illustrates the limits and potentials of these cell lines as tools for neuropharmacological exploration.
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Affiliation(s)
- Kathleen Yin
- Centre for Pain Research, Institute for Molecular Bioscience, University of Queensland, Queensland, Australia Pharmacy Australia Centre of Excellence, University of Queensland, Queensland, Australia
| | - Gregory J Baillie
- Centre for Pain Research, Institute for Molecular Bioscience, University of Queensland, Queensland, Australia
| | - Irina Vetter
- Centre for Pain Research, Institute for Molecular Bioscience, University of Queensland, Queensland, Australia Pharmacy Australia Centre of Excellence, University of Queensland, Queensland, Australia
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Regnier G, Bocksteins E, Van de Vijver G, Snyders DJ, van Bogaert PP. The contribution of Kv2.2-mediated currents decreases during the postnatal development of mouse dorsal root ganglion neurons. Physiol Rep 2016; 4:4/6/e12731. [PMID: 27033450 PMCID: PMC4814888 DOI: 10.14814/phy2.12731] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 02/12/2016] [Indexed: 11/24/2022] Open
Abstract
Delayed rectifier voltage-gated K(+)(Kv) channels play an important role in the regulation of the electrophysiological properties of neurons. In mouse dorsal root ganglion (DRG) neurons, a large fraction of the delayed rectifier current is carried by both homotetrameric Kv2 channels and heterotetrameric channels consisting of Kv2 and silent Kv (KvS) subunits (i.e., Kv5-Kv6 and Kv8-Kv9). However, little is known about the contribution of Kv2-mediated currents during the postnatal development ofDRGneurons. Here, we report that the Stromatoxin-1 (ScTx)-sensitive fraction of the total outward K(+)current (IK) from mouseDRGneurons gradually decreased (~13%,P < 0.05) during the first month of postnatal development. Because ScTx inhibits both Kv2.1- and Kv2.2-mediated currents, this gradual decrease may reflect a decrease in currents containing either subunit. However, the fraction of Kv2.1 antibody-sensitive current that only reflects the Kv2.1-mediated currents remained constant during that same period. These results suggested that the fractional contribution of Kv2.2-mediated currents relative toIKdecreased with postnatal age. SemiquantitativeRT-PCRanalysis indicated that this decrease can be attributed to developmental changes in Kv2.2 expression as themRNAlevels of the Kv2.2 subunit decreased gradually between 1 and 4 weeks of age. In addition, we observed age-dependent fluctuations in themRNAlevels of the Kv6.3, Kv8.1, Kv9.1, and Kv9.3 subunits. These results support an important role of both Kv2 and KvS subunits in the postnatal maturation ofDRGneurons.
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Affiliation(s)
- Glenn Regnier
- Laboratory for Molecular Biophysics, Physiology and Pharmacology, Department of Biomedical Sciences, University of Antwerp, CDE, Antwerpen, Belgium
| | - Elke Bocksteins
- Laboratory for Molecular Biophysics, Physiology and Pharmacology, Department of Biomedical Sciences, University of Antwerp, CDE, Antwerpen, Belgium
| | - Gerda Van de Vijver
- Laboratory for Cardiovascular Research, Institute Born-Bunge University of Antwerp, CDE, Antwerpen, Belgium
| | - Dirk J Snyders
- Laboratory for Molecular Biophysics, Physiology and Pharmacology, Department of Biomedical Sciences, University of Antwerp, CDE, Antwerpen, Belgium
| | - Pierre-Paul van Bogaert
- Laboratory for Cardiovascular Research, Institute Born-Bunge University of Antwerp, CDE, Antwerpen, Belgium
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Wu S, Marie Lutz B, Miao X, Liang L, Mo K, Chang YJ, Du P, Soteropoulos P, Tian B, Kaufman AG, Bekker A, Hu Y, Tao YX. Dorsal root ganglion transcriptome analysis following peripheral nerve injury in mice. Mol Pain 2016; 12:12/0/1744806916629048. [PMID: 27030721 PMCID: PMC4955972 DOI: 10.1177/1744806916629048] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/30/2015] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Peripheral nerve injury leads to changes in gene expression in primary sensory neurons of the injured dorsal root ganglia. These changes are believed to be involved in neuropathic pain genesis. Previously, these changes have been identified using gene microarrays or next generation RNA sequencing with poly-A tail selection, but these approaches cannot provide a more thorough analysis of gene expression alterations after nerve injury. METHODS The present study chose to eliminate mRNA poly-A tail selection and perform strand-specific next generation RNA sequencing to analyze whole transcriptomes in the injured dorsal root ganglia following spinal nerve ligation. Quantitative real-time reverse transcriptase polymerase chain reaction assay was carried out to verify the changes of some differentially expressed RNAs in the injured dorsal root ganglia after spinal nerve ligation. RESULTS Our results showed that more than 50 million (M) paired mapped sequences with strand information were yielded in each group (51.87 M-56.12 M in sham vs. 51.08 M-57.99 M in spinal nerve ligation). Six days after spinal nerve ligation, expression levels of 11,163 out of a total of 27,463 identified genes in the injured dorsal root ganglia significantly changed, of which 52.14% were upregulated and 47.86% downregulated. The largest transcriptional changes were observed in protein-coding genes (91.5%) followed by noncoding RNAs. Within 944 differentially expressed noncoding RNAs, the most significant changes were seen in long interspersed noncoding RNAs followed by antisense RNAs, processed transcripts, and pseudogenes. We observed a notable proportion of reads aligning to intronic regions in both groups (44.0% in sham vs. 49.6% in spinal nerve ligation). Using quantitative real-time polymerase chain reaction, we confirmed consistent differential expression of selected genes including Kcna2, Oprm1 as well as lncRNAs Gm21781 and 4732491K20Rik following spinal nerve ligation. CONCLUSION Our findings suggest that next generation RNA sequencing can be used as a promising approach to analyze the changes of whole transcriptomes in dorsal root ganglia following nerve injury and to possibly identify new targets for prevention and treatment of neuropathic pain.
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Affiliation(s)
- Shaogen Wu
- Department of Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Jiangsu, China Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Brianna Marie Lutz
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Xuerong Miao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA Department of Anesthesiology and Intensive Care, Eastern Hepatobiliary Surgical Hospital, The Second Military Medical University, Shanghai, China
| | - Lingli Liang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Kai Mo
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA Department of Anesthesiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Yun-Juan Chang
- High Performance and Research Computing, Office of Information Technology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Peicheng Du
- High Performance and Research Computing, Office of Information Technology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Patricia Soteropoulos
- Departments of Biochemistry & Microbiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Bin Tian
- Departments of Biochemistry & Microbiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Andrew G Kaufman
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Alex Bekker
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Yali Hu
- Department of Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Jiangsu, China
| | - Yuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA Departments of Cell Biology & Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA Department of Pharmacology & Physiology and Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
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Sleigh JN, Weir GA, Schiavo G. A simple, step-by-step dissection protocol for the rapid isolation of mouse dorsal root ganglia. BMC Res Notes 2016; 9:82. [PMID: 26864470 PMCID: PMC4750296 DOI: 10.1186/s13104-016-1915-8] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/03/2016] [Indexed: 11/25/2022] Open
Abstract
Background The cell bodies of sensory neurons, which transmit information from the external environment to the spinal cord, can be found at all levels of the spinal column in paired structures called dorsal root ganglia (DRG). Rodent DRG neurons have long been studied in the laboratory to improve understanding of sensory nerve development and function, and have been instrumental in determining mechanisms underlying pain and neurodegeneration in disorders of the peripheral nervous system. Here, we describe a simple, step-by-step protocol for the swift isolation of mouse DRG, which can be enzymatically dissociated to produce fully differentiated primary neuronal cultures, or processed for downstream analyses, such as immunohistochemistry or RNA profiling. Findings After dissecting out the spinal column, from the base of the skull to the level of the femurs, it can be cut down the mid-line and the spinal cord and meninges removed, before extracting the DRG and detaching unwanted axons. This protocol allows the easy and rapid isolation of DRG with minimal practice and dissection experience. The process is both faster and less technically challenging than extracting the ganglia from the in situ column after performing a dorsal laminectomy. Conclusions This approach reduces the time required to collect DRG, thereby improving efficiency, permitting less opportunity for tissue deterioration, and, ultimately, increasing the chances of generating healthy primary DRG cultures or high quality, reproducible experiments using DRG tissue.
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Affiliation(s)
- James N Sleigh
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, WC1 N 3BG, UK.
| | - Greg A Weir
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK.
| | - Giampietro Schiavo
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, WC1 N 3BG, UK.
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Tang M, Wu G, Wang Z, Yang N, Shi H, He Q, Zhu C, Yang Y, Yu G, Wang C, Yuan X, Liu Q, Guan Y, Dong X, Tang Z. Voltage-gated potassium channels involved in regulation of physiological function in MrgprA3-specific itch neurons. Brain Res 2016; 1636:161-171. [PMID: 26874069 DOI: 10.1016/j.brainres.2016.02.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 01/20/2016] [Accepted: 02/04/2016] [Indexed: 12/19/2022]
Abstract
Itch is described as an unpleasant or irritating skin sensation that elicits the desire or reflex to scratch. MrgprA3, one of members of the Mrgprs family, is specifically expressed in a subpopulation of dorsal root ganglion (DRG) in the peripheral nervous system (PNS). These MrgprA3-expressing DRG neurons have been identified as itch-specific neurons. They can be activated by the compound, chloroquine, which is used as a drug to treat malaria. In the present study, we labeled these itch-specific neurons using the method of molecular genetic markers, and then studied their electrophysiological properties. We also recorded the cutaneous MrgprA3(-) neurons retrogradely labeled by Dil dye (MrgprA3(-)-Dil). We first found that MrgprA3(+) neurons have a lower excitability than MrgprA3(-) neurons (MrgprA3(-)-non-Dil and MrgprA3(-)-Dil). The number of action potential (AP) was reduced more obviously in MrgprA3(+) neurons than that of in MrgprA3(-) neurons. In most cases, MrgprA3(+) neurons only generated single AP; however, in MrgprA3(-) neurons, the same stimulation could induce multiple AP firing due to the greater voltage-gated potassium (Kv) current existence in MrgprA3(+) than in MrgprA3(-) neurons. Thus, Kv current plays an important role in the regulation of excitability in itch-specific neurons.
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Affiliation(s)
- Min Tang
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China; College of Biology and Environmental Sciences, Jishou University, Jishou, China
| | - Guanyi Wu
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China; College of Basic Medicine, Guangxi University of Chinese Medicine, Nanning, China
| | - Zhongli Wang
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Niuniu Yang
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Hao Shi
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Qian He
- College of Biology and Environmental Sciences, Jishou University, Jishou, China
| | - Chan Zhu
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yan Yang
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Guang Yu
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Changming Wang
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xiaolin Yuan
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Qin Liu
- Department of Anesthesiology, Washington University in St. Louis, USA
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University Schools of Medicine, Baltimore, MD, USA
| | - Xinzhong Dong
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zongxiang Tang
- College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing, China.
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47
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Bocksteins E. Kv5, Kv6, Kv8, and Kv9 subunits: No simple silent bystanders. J Gen Physiol 2016; 147:105-25. [PMID: 26755771 PMCID: PMC4727947 DOI: 10.1085/jgp.201511507] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 12/11/2015] [Indexed: 12/19/2022] Open
Abstract
Members of the electrically silent voltage-gated K(+) (Kv) subfamilies (Kv5, Kv6, Kv8, and Kv9, collectively identified as electrically silent voltage-gated K(+) channel [KvS] subunits) do not form functional homotetrameric channels but assemble with Kv2 subunits into heterotetrameric Kv2/KvS channels with unique biophysical properties. Unlike the ubiquitously expressed Kv2 subunits, KvS subunits show a more restricted expression. This raises the possibility that Kv2/KvS heterotetramers have tissue-specific functions, making them potential targets for the development of novel therapeutic strategies. Here, I provide an overview of the expression of KvS subunits in different tissues and discuss their proposed role in various physiological and pathophysiological processes. This overview demonstrates the importance of KvS subunits and Kv2/KvS heterotetramers in vivo and the importance of considering KvS subunits and Kv2/KvS heterotetramers in the development of novel treatments.
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Affiliation(s)
- Elke Bocksteins
- Laboratory for Molecular Biophysics, Physiology, and Pharmacology, Department for Biomedical Sciences, University of Antwerp, 2610 Antwerp, Belgium
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Abstract
PURPOSE OF REVIEW Poor management of chronic pain remains a significant cause of misery with huge socioeconomic costs. Accumulating research in potassium (K+) channel physiology has uncovered several promising leads for the development of novel analgesics. RECENT FINDINGS We now recognize that certain K+ channel subunits are directly gated to pain-relevant stimuli (Kv1.1, K2P) whereas others are specifically modulated by inflammatory processes (Kv7, BKCA, K2P). Genetic analyses illustrate that K+ channel gene variation can predict pain sensitivity (KCNS1, GIRKs), risk for persistent pain (KCNS1, GIRKs, TRESK) and analgesic effectiveness (GIRK2). Importantly, preclinical studies confirm that K+ channel dysfunction can be a pain trigger in traumatic neuropathies (Kv9.1/Kv2.1, Kv7, Kv1.2) and migraine (TRESK). Finally, emerging data suggest that even pain in diabetes, bone cancer and autoimmune neuropathies may have K+ channel dysfunction constituents. SUMMARY There is a long-sought need for superior pharmacotherapy of pain syndromes. Although universal enhancement of K+ channel function in the periphery can decrease nociceptive excitability irrespective of the underlying cause, a more refined targeting of subunits with dominant nociceptive roles could yield highly efficacious treatments with fewer side-effects. The ongoing characterization of molecular interactions linking K+ channel dysfunction to pain is instrumental for identifying candidates with the most therapeutic potential.
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50
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Zamponi GW, Han C, Waxman SG. Voltage-Gated Ion Channels as Molecular Targets for Pain. Transl Neurosci 2016. [DOI: 10.1007/978-1-4899-7654-3_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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