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Seemab K, Khan AU, Khan MI, Qazi NG, Minhas AM, Ali F. Anti-pruritic effect of L-carnitine against chloroquine-induced pruritus mediated via nitric oxide pathway. BMC Pharmacol Toxicol 2024; 25:32. [PMID: 38778384 PMCID: PMC11110330 DOI: 10.1186/s40360-024-00748-4] [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: 11/12/2023] [Accepted: 03/22/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Pruritus, or itching, is a distressing symptom associated with various dermatological and systemic diseases. L-carnitine (βeta hydroxy-γ-tri methyl amino-butyric acid), is a naturally occurring substance, it controls numerous physiological processes. The present research aims to identify L-carnitine for its anti-pruritic effect via nitric oxide-dependent mechanism. METHODS Chloroquine-induced pruritus serves as an experimental model to investigate possible therapeutic interventions. In this study, we evaluated the efficacy of L-carnitine in combating oxidative stress, nitric oxide, and inflammatory cytokines in a chloroquine-induced pruritus model. RESULTS L-carnitine treatment significantly reduced scratching behavior compared to the disease group (***P < 0.001 vs. chloroquine group), indicating its antipruritic potential. The markers of oxidative stress, GST, GSH, Catalase, and LPO were dysregulated in the disease model, but administration of L-carnitine restored GST, GSH, and Catalase levels and decreased LPO levels (***P < 0.001 vs. chloroquine group), thereby alleviating oxidative stress. L-carnitine also reduced nitric oxide synthase (NOS) activity, suggesting that it modulates nitric oxide signaling pathways involved in pruritus. In addition, L-carnitine lowered levels of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), inflammatory marker nuclear factor kappa B (p-NFκB) and also reduces an inflammatory enzyme, cyclooxygenase-2 (COX-2), determined by ELISA (Enzyme-Linked Immunosorbent Assay) (***P < 0.001 vs. chloroquine group). It downregulates nNOS mRNA expression confirmed by real-time polymerase chain reaction (RT-PCR). CONCLUSION These findings highlight the therapeutic effects of L-carnitine in alleviating chloroquine-induced pruritus.
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Affiliation(s)
- Kiran Seemab
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Arif-Ullah Khan
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan.
| | - Muhammad Imran Khan
- Department of Biomedical Science, Pak-Austria Fachhochule: Institute of Applied Science and Technology, Mang Haripur, KPK, Pakistan
| | - Neelum Gul Qazi
- Department of Pharmacy, Iqra University, Islamabad, Pakistan.
| | - Amber Mahmood Minhas
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Fawad Ali
- Department of Pharmacy, Kohat University of Science and Technology, Kohat, Pakistan
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Upadhyay A, Gradwell MA, Vajtay TJ, Conner J, Sanyal AA, Azadegan C, Patel KR, Thackray JK, Bohic M, Imai F, Ogundare SO, Yoshida Y, Abdus-Saboor I, Azim E, Abraira VE. The Dorsal Column Nuclei Scale Mechanical Sensitivity in Naive and Neuropathic Pain States. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.20.581208. [PMID: 38712022 PMCID: PMC11071288 DOI: 10.1101/2024.02.20.581208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Tactile perception relies on reliable transmission and modulation of low-threshold information as it travels from the periphery to the brain. During pathological conditions, tactile stimuli can aberrantly engage nociceptive pathways leading to the perception of touch as pain, known as mechanical allodynia. Two main drivers of peripheral tactile information, low-threshold mechanoreceptors (LTMRs) and postsynaptic dorsal column neurons (PSDCs), terminate in the brainstem dorsal column nuclei (DCN). Activity within the DRG, spinal cord, and DCN have all been implicated in mediating allodynia, yet the DCN remains understudied at the cellular, circuit, and functional levels compared to the other two. Here, we show that the gracile nucleus (Gr) of the DCN mediates tactile sensitivity for low-threshold stimuli and contributes to mechanical allodynia during neuropathic pain in mice. We found that the Gr contains local inhibitory interneurons in addition to thalamus-projecting neurons, which are differentially innervated by primary afferents and spinal inputs. Functional manipulations of these distinct Gr neuronal populations resulted in bidirectional changes to tactile sensitivity, but did not affect noxious mechanical or thermal sensitivity. During neuropathic pain, silencing Gr projection neurons or activating Gr inhibitory neurons was able to reduce tactile hypersensitivity, and enhancing inhibition was able to ameliorate paw withdrawal signatures of neuropathic pain, like shaking. Collectively, these results suggest that the Gr plays a specific role in mediating hypersensitivity to low-threshold, innocuous mechanical stimuli during neuropathic pain, and that Gr activity contributes to affective, pain-associated phenotypes of mechanical allodynia. Therefore, these brainstem circuits work in tandem with traditional spinal circuits underlying allodynia, resulting in enhanced signaling of tactile stimuli in the brain during neuropathic pain.
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Affiliation(s)
- Aman Upadhyay
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
- Neuroscience PhD program at Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Mark A Gradwell
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
| | - Thomas J Vajtay
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - James Conner
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Arnab A Sanyal
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Chloe Azadegan
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Komal R Patel
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Joshua K Thackray
- Human Genetics Institute of New Jersey, Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Manon Bohic
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
| | - Fumiyasu Imai
- Burke Neurological Institute, White Plains, New York City, New York, USA
- Brain and Mind Research Institute, Weill Cornell Medicine, New York City, New York, USA
| | - Simon O Ogundare
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Department of Biological Sciences, Columbia University, New York City, New York, USA
| | - Yutaka Yoshida
- Burke Neurological Institute, White Plains, New York City, New York, USA
- Brain and Mind Research Institute, Weill Cornell Medicine, New York City, New York, USA
| | - Ishmail Abdus-Saboor
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Department of Biological Sciences, Columbia University, New York City, New York, USA
| | - Eiman Azim
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Victoria E Abraira
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
- Lead contact
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3
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Safronov BV, Szucs P. Novel aspects of signal processing in lamina I. Neuropharmacology 2024; 247:109858. [PMID: 38286189 DOI: 10.1016/j.neuropharm.2024.109858] [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: 11/24/2023] [Revised: 01/12/2024] [Accepted: 01/25/2024] [Indexed: 01/31/2024]
Abstract
The most superficial layer of the spinal dorsal horn, lamina I, is a key element of the nociceptive processing system. It contains different types of projection neurons (PNs) and local-circuit neurons (LCNs) whose functional roles in the signal processing are poorly understood. This article reviews recent progress in elucidating novel anatomical features and physiological properties of lamina I PNs and LCNs revealed by whole-cell recordings in ex vivo spinal cord. This article is part of the Special Issue on "Ukrainian Neuroscience".
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Affiliation(s)
- Boris V Safronov
- Neuronal Networks Group, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.
| | - Peter Szucs
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; HUN-REN-DE Neuroscience Research Group, Debrecen, Hungary
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Qi L, Iskols M, Shi D, Reddy P, Walker C, Lezgiyeva K, Voisin T, Pawlak M, Kuchroo VK, Chiu IM, Ginty DD, Sharma N. A mouse DRG genetic toolkit reveals morphological and physiological diversity of somatosensory neuron subtypes. Cell 2024; 187:1508-1526.e16. [PMID: 38442711 PMCID: PMC10947841 DOI: 10.1016/j.cell.2024.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 11/12/2023] [Accepted: 02/05/2024] [Indexed: 03/07/2024]
Abstract
Dorsal root ganglia (DRG) somatosensory neurons detect mechanical, thermal, and chemical stimuli acting on the body. Achieving a holistic view of how different DRG neuron subtypes relay neural signals from the periphery to the CNS has been challenging with existing tools. Here, we develop and curate a mouse genetic toolkit that allows for interrogating the properties and functions of distinct cutaneous targeting DRG neuron subtypes. These tools have enabled a broad morphological analysis, which revealed distinct cutaneous axon arborization areas and branching patterns of the transcriptionally distinct DRG neuron subtypes. Moreover, in vivo physiological analysis revealed that each subtype has a distinct threshold and range of responses to mechanical and/or thermal stimuli. These findings support a model in which morphologically and physiologically distinct cutaneous DRG sensory neuron subtypes tile mechanical and thermal stimulus space to collectively encode a wide range of natural stimuli.
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Affiliation(s)
- Lijun Qi
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Michael Iskols
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - David Shi
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Pranav Reddy
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Christopher Walker
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Karina Lezgiyeva
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Tiphaine Voisin
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Mathias Pawlak
- Gene Lay Institute of Immunology and Inflammation, Brigham and Women's Hospital, Mass General Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Vijay K Kuchroo
- Gene Lay Institute of Immunology and Inflammation, Brigham and Women's Hospital, Mass General Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Isaac M Chiu
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - David D Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
| | - Nikhil Sharma
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA.
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5
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Kaneko T, Oura A, Imai Y, Kusumoto-Yoshida I, Kanekura T, Okuno H, Kuwaki T, Kashiwadani H. Orexin neurons play contrasting roles in itch and pain neural processing via projecting to the periaqueductal gray. Commun Biol 2024; 7:290. [PMID: 38459114 PMCID: PMC10923787 DOI: 10.1038/s42003-024-05997-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 02/28/2024] [Indexed: 03/10/2024] Open
Abstract
Pain and itch are recognized as antagonistically regulated sensations; pain suppresses itch, whilst pain inhibition enhances itch. The neural mechanisms at the central nervous system (CNS) underlying these pain-itch interactions still need to be explored. Here, we revealed the contrasting role of orexin-producing neurons (ORX neurons) in the lateral hypothalamus (LH), which suppresses pain while enhancing itch neural processing, by applying optogenetics to the acute pruritus and pain model. We also revealed that the circuit of ORX neurons from LH to periaqueductal gray regions served in the contrasting modulation of itch and pain processing using optogenetic terminal inhibition techniques. Additionally, by using an atopic dermatitis model, we confirmed the involvement of ORX neurons in regulating chronic itch processing, which could lead to a novel therapeutic target for persistent pruritus in clinical settings. Our findings provide new insight into the mechanism of antagonistic regulation between pain and itch in the CNS.
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Affiliation(s)
- Tatsuroh Kaneko
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
| | - Asuka Oura
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Yoshiki Imai
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Ikue Kusumoto-Yoshida
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Takuro Kanekura
- Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Hiroyuki Okuno
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Tomoyuki Kuwaki
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Hideki Kashiwadani
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
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Zhou J, Zhang B, Zhou X, Zhang F, Shu Q, Wu Y, Chang HM, Hu L, Cai RL, Yu Q. Electroacupuncture pretreatment mediates sympathetic nerves to alleviate myocardial ischemia-reperfusion injury via CRH neurons in the paraventricular nucleus of the hypothalamus. Chin Med 2024; 19:43. [PMID: 38448912 PMCID: PMC10916233 DOI: 10.1186/s13020-024-00916-y] [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: 12/01/2023] [Accepted: 02/26/2024] [Indexed: 03/08/2024] Open
Abstract
BACKGROUND Myocardial ischemia-reperfusion can further exacerbate myocardial injury and increase the risk of death. Our previous research found that the paraventricular nucleus (PVN) of the hypothalamus plays a crucial role in the improvement of myocardial ischemia-reperfusion injury (MIRI) by electroacupuncture (EA) pretreatment, but its mechanism of action is still unclear. CRH neurons exhibit periodic concentrated expression in PVN, but further research is needed to determine whether they are involved in the improvement of MIRI by EA pretreatment. Meanwhile, numerous studies have shown that changes in sympathetic nervous system innervation and activity are associated with many heart diseases. This study aims to investigate whether EA pretreatment improves MIRI through sympathetic nervous system mediated by PVNCRH neurons. METHODS Integrated use of fiber-optic recording, chemical genetics and other methods to detect relevant indicators: ECG signals were acquired through Powerlab standard II leads, and LabChart 8 calculated heart rate, ST-segment offset, and heart rate variability (HRV); Left ventricular ejection fraction (LVEF), left ventricular short-axis shortening (LVFS), left ventricular end-systolic internal diameter (LVIDs) and interventricular septal thickness (IVSs) were measured by echocardiography; Myocardial infarct area (IA) and area at risk (AAR) were calculated by Evans-TTC staining. Pathological changes in cardiomyocytes were observed by HE staining; Changes in PVNCRH neuronal activity were recorded by fiber-optic photometry; Sympathetic nerve discharges were recorded for in vivo electrophysiology; NE and TH protein expression was assayed by Western blot. RESULTS Our data indicated that EA pretreatment can effectively alleviate MIRI. Meanwhile, we found that in the MIRI model, the number and activity of CRH neurons co labeled with c-Fos in the PVN area of the rat brain increased, and the frequency of sympathetic nerve discharge increased. EA pretreatment could reverse this change. In addition, the results of chemical genetics indicated that inhibiting PVNCRH neurons has a similar protective effect on MIRI as EA pretreatment, and the activation of PVNCRH neurons can counteract this protective effect. CONCLUSION EA pretreatment can inhibit PVNCRH neurons and improve MIRI by inhibiting sympathetic nerve, which offers fresh perspectives on the application of acupuncture in the management of cardiovascular disease.
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Affiliation(s)
- Jie Zhou
- College of Acupuncture and Moxibustion, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Bin Zhang
- College of Acupuncture and Moxibustion, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Xiang Zhou
- College of Acupuncture and Moxibustion, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Fan Zhang
- College of Acupuncture and Moxibustion, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Qi Shu
- College of Acupuncture and Moxibustion, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Yan Wu
- College of Acupuncture and Moxibustion, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Hui-Min Chang
- College of Acupuncture and Moxibustion, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Ling Hu
- Institute of Acupuncture and Meridian Research, Anhui Academy of Chinese Medicine, Hefei, 230038, China
- Key Laboratory of Xin'an Medicine, Ministry of Education, Hefei, 230038, China
| | - Rong-Lin Cai
- Center for Xin'an Medicine and Modernization of Traditional Chinese Medicine, Insitute of Health and Medicine, Hefei Comprehensive National Science Center, Hefei, 230601, China.
- Institute of Acupuncture and Meridian Research, Anhui Academy of Chinese Medicine, Hefei, 230038, China.
- Anhui Province Key Laboratory of Meridian Viscera Correlationship, Hefei, 230038, China.
- Key Laboratory of Xin'an Medicine, Ministry of Education, Hefei, 230038, China.
| | - Qing Yu
- Institute of Acupuncture and Meridian Research, Anhui Academy of Chinese Medicine, Hefei, 230038, China.
- Anhui Province Key Laboratory of Meridian Viscera Correlationship, Hefei, 230038, China.
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7
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Metcalfe M, Steward O. PTEN deletion in spinal pathways via retrograde transduction with AAV-RG enhances forelimb motor recovery after cervical spinal cord injury; Sex differences and late-onset pathophysiologies. Exp Neurol 2023; 370:114551. [PMID: 37778650 DOI: 10.1016/j.expneurol.2023.114551] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/08/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Spinal cord injuries (SCI) cause permanent functional impairments due to interruption of motor and sensory pathways. Regeneration of axons does not occur due to lack of intrinsic growth capacity of adult neurons and extrinsic inhibitory factors, especially at the injury site. However, some regeneration can be achieved via deletion of the phosphatase and tensin homolog (PTEN) in cells of origin of spinal pathways. Here, we deployed an AAV variant that is retrogradely transported (AAV-rg) to deliver gene modifying cargos to the cells of origin of multiple pathways interrupted by SCI, testing whether this promoted recovery of motor function. PTENf/f;RosatdTomato mice and control RosatdTomato mice received injections of different doses (number of genome copies, GCs) of AAV-rg/Cre into the cervical spinal cord at the time of a C5 dorsal hemisection injury. Forelimb grip strength was tested over time using a grip strength meter. PTENf/f;RosatdTomato mice with AAV-rg/Cre (PTEN-deleted) exhibited substantial improvements in forelimb gripping ability in comparison to controls. Of note, there were major sex differences in the extent of recovery, with male mice exhibiting greater recovery than females. However, at around 5-7 weeks post-injury/injection, many mice with SCI and AAV-rg-mediated PTEN deletion began to exhibit pathophysiologies involving excessive scratching of the ears and back of the neck and rigid forward extension of the hindlimbs. These pathophysiologies increased in incidence and severity over time. Our results reveal that although intra-spinal injections of AAV-rg/Cre in PTENf/f;RosatdTomato mice can enhance forelimb motor recovery after SCI, late-developing functional abnormalities occur with the experimental conditions used here. Mechanisms underlying late-developing pathophysiologies remain to be defined.
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Affiliation(s)
- Mariajose Metcalfe
- Reeve-Irvine Research Center University of California Irvine School of Medicine, USA; Department of Anatomy & Neurobiology, University of California Irvine School of Medicine, USA
| | - Oswald Steward
- Reeve-Irvine Research Center University of California Irvine School of Medicine, USA; Department of Anatomy & Neurobiology, University of California Irvine School of Medicine, USA; Department of Neurobiology & Behavior, University of California Irvine, USA; Department of Neurosurgery, University of California Irvine School of Medicine, USA.
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8
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Guo C, Jiang H, Huang CC, Li F, Olson W, Yang W, Fleming M, Yu G, Hoekel G, Luo W, Liu Q. Pain and itch coding mechanisms of polymodal sensory neurons. Cell Rep 2023; 42:113316. [PMID: 37889748 PMCID: PMC10729537 DOI: 10.1016/j.celrep.2023.113316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 09/05/2023] [Accepted: 10/06/2023] [Indexed: 10/29/2023] Open
Abstract
Pain and itch coding mechanisms in polymodal sensory neurons remain elusive. MrgprD+ neurons represent a major polymodal population and mediate both mechanical pain and nonhistaminergic itch. Here, we show that chemogenetic activation of MrgprD+ neurons elicited both pain- and itch-related behavior in a dose-dependent manner, revealing an unanticipated compatibility between pain and itch in polymodal neurons. While VGlut2-dependent glutamate release is required for both pain and itch transmission from MrgprD+ neurons, the neuropeptide neuromedin B (NMB) is selectively required for itch signaling. Electrophysiological recordings further demonstrated that glutamate synergizes with NMB to excite NMB-sensitive postsynaptic neurons. Ablation of these spinal neurons selectively abolished itch signals from MrgprD+ neurons, without affecting pain signals, suggesting a dedicated itch-processing central circuit. These findings reveal distinct neurotransmitters and neural circuit requirements for pain and itch signaling from MrgprD+ polymodal sensory neurons, providing new insights on coding and processing of pain and itch.
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Affiliation(s)
- Changxiong Guo
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Haowu Jiang
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Cheng-Chiu Huang
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Fengxian Li
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - William Olson
- Department of Neuroscience, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Weishan Yang
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Michael Fleming
- Department of Neuroscience, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Guang Yu
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - George Hoekel
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Wenqin Luo
- Department of Neuroscience, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Qin Liu
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA.
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Metcalfe M, Steward O. PTEN deletion in spinal pathways via retrograde transduction with AAV-rg enhances forelimb motor recovery after cervical spinal cord injury; sex differences and late-onset pathophysiologies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.20.533502. [PMID: 36993317 PMCID: PMC10055283 DOI: 10.1101/2023.03.20.533502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Spinal cord injuries (SCI) cause permanent functional impairments due to interruption of motor and sensory pathways. Regeneration of axons does not occur due to lack of intrinsic growth capacity of adult neurons and extrinsic inhibitory factors, especially at the injury site. However, some regeneration can be achieved via deletion of the phosphatase and tensin homolog (PTEN) in cells of origin of spinal pathways. Here, we deployed an AAV variant that is retrogradely transported (AAV-rg) to deliver gene modifying cargos to the cells of origin of multiple pathways interrupted by SCI, testing whether this promoted recovery of motor function. PTEN f/f ;Rosa tdTomato mice and control Rosa tdTomato mice received injections of different doses (number of genome copies, GCs) of AAV-rg/Cre into the cervical spinal cord at the time of a C5 dorsal hemisection injury. Forelimb grip strength was tested over time using a grip strength meter. PTEN f/f ;Rosa tdTomato mice with AAV-rg/Cre (PTEN-deleted) exhibited substantial improvements in forelimb gripping ability in comparison to controls. Of note, there were major sex differences in the extent of recovery, with male mice exhibiting greater recovery than females. However, at around 5-7 weeks post-injury/injection, many mice with SCI and AAV-rg-mediated PTEN deletion began to exhibit pathophysiologies involving excessive scratching of the ears and back of the neck and rigid forward extension of the hindlimbs. These pathophysiologies increased in incidence and severity over time. Our results reveal that although intra-spinal injections of AAV-rg/Cre in PTEN f/f ;Rosa tdTomato mice can enhance forelimb motor recovery after SCI, late-developing functional abnormalities occur with the experimental conditions used here. Mechanisms underlying late-developing pathophysiologies remain to be defined.
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Pan Q, Guo SS, Chen M, Su XY, Gao ZL, Wang Q, Xu TL, Liu MG, Hu J. Representation and control of pain and itch by distinct prefrontal neural ensembles. Neuron 2023:S0896-6273(23)00342-2. [PMID: 37224813 DOI: 10.1016/j.neuron.2023.04.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 02/18/2023] [Accepted: 04/27/2023] [Indexed: 05/26/2023]
Abstract
Pain and itch are two closely related but essentially distinct sensations that elicit different behavioral responses. However, it remains mysterious how pain and itch information is encoded in the brain to produce differential perceptions. Here, we report that nociceptive and pruriceptive signals are separately represented and processed by distinct neural ensembles in the prelimbic (PL) subdivision of the medial prefrontal cortex (mPFC) in mice. Pain- and itch-responsive cortical neural ensembles were found to significantly differ in electrophysiological properties, input-output connectivity profiles, and activity patterns to nociceptive or pruriceptive stimuli. Moreover, these two groups of cortical neural ensembles oppositely modulate pain- or itch-related sensory and emotional behaviors through their preferential projections to specific downstream regions such as the mediodorsal thalamus (MD) and basolateral amygdala (BLA). These findings uncover separate representations of pain and itch by distinct prefrontal neural ensembles and provide a new framework for understanding somatosensory information processing in the brain.
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Affiliation(s)
- Qian Pan
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Su-Shan Guo
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Ming Chen
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xin-Yu Su
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Zi-Long Gao
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Qi Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Tian-Le Xu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Songjiang Hospital and Songjiang Research Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 201600, China; Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai 201210, China.
| | - Ming-Gang Liu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
| | - Ji Hu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai 200030, China.
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11
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Liu AW, Gillis JE, Sumpter TL, Kaplan DH. Neuroimmune interactions in atopic and allergic contact dermatitis. J Allergy Clin Immunol 2023; 151:1169-1177. [PMID: 37149370 PMCID: PMC10167546 DOI: 10.1016/j.jaci.2023.03.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/13/2023] [Accepted: 03/16/2023] [Indexed: 05/08/2023]
Abstract
The skin is a barrier organ populated by many types of skin-resident immune cells and sensory neurons. It has become increasingly appreciated that neuroimmune interactions are an important component of inflammatory diseases such as atopic dermatitis and allergic contact dermatitis. Neuropeptides secreted from nerve terminals play an important role in mediating cutaneous immune cell function, and soluble mediators derived from immune cells interact with neurons to induce itch. In this review article, we will explore emerging research describing neuronal effector functions on skin immune cells in mouse models of atopic and contact dermatitis. We will also discuss the contributions of both specific neuronal subsets and secreted immune factors to itch induction and the associated inflammatory processes. Finally, we will explore how treatment strategies have emerged around these findings and discuss the relationship between scratching and dermatitis.
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Affiliation(s)
- Andrew W Liu
- Department of Dermatology, University of Pittsburgh, Pittsburgh, Pa; Department of Immunology, University of Pittsburgh, Pittsburgh, Pa
| | - Jacob E Gillis
- Department of Dermatology, University of Pittsburgh, Pittsburgh, Pa; Department of Immunology, University of Pittsburgh, Pittsburgh, Pa
| | - Tina L Sumpter
- Department of Dermatology, University of Pittsburgh, Pittsburgh, Pa; Department of Immunology, University of Pittsburgh, Pittsburgh, Pa
| | - Daniel H Kaplan
- Department of Dermatology, University of Pittsburgh, Pittsburgh, Pa; Department of Immunology, University of Pittsburgh, Pittsburgh, Pa.
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12
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Qi L, Iskols M, Shi D, Reddy P, Walker C, Lezgiyeva K, Voisin T, Pawlak M, Kuchroo VK, Chiu I, Ginty DD, Sharma N. A DRG genetic toolkit reveals molecular, morphological, and functional diversity of somatosensory neuron subtypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.22.537932. [PMID: 37131664 PMCID: PMC10153270 DOI: 10.1101/2023.04.22.537932] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Mechanical and thermal stimuli acting on the skin are detected by morphologically and physiologically distinct sensory neurons of the dorsal root ganglia (DRG). Achieving a holistic view of how this diverse neuronal population relays sensory information from the skin to the central nervous system (CNS) has been challenging with existing tools. Here, we used transcriptomic datasets of the mouse DRG to guide development and curation of a genetic toolkit to interrogate transcriptionally defined DRG neuron subtypes. Morphological analysis revealed unique cutaneous axon arborization areas and branching patterns of each subtype. Physiological analysis showed that subtypes exhibit distinct thresholds and ranges of responses to mechanical and/or thermal stimuli. The somatosensory neuron toolbox thus enables comprehensive phenotyping of most principal sensory neuron subtypes. Moreover, our findings support a population coding scheme in which the activation thresholds of morphologically and physiologically distinct cutaneous DRG neuron subtypes tile multiple dimensions of stimulus space.
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Affiliation(s)
- Lijun Qi
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115
| | - Michael Iskols
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115
| | - David Shi
- Department of Molecular Pharmacology and Therapeutics, Department of Systems Biology, Columbia University, New York, NY
| | - Pranav Reddy
- Department of Molecular Pharmacology and Therapeutics, Department of Systems Biology, Columbia University, New York, NY
| | - Christopher Walker
- Department of Molecular Pharmacology and Therapeutics, Department of Systems Biology, Columbia University, New York, NY
| | - Karina Lezgiyeva
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115
| | - Tiphaine Voisin
- Department of Immunology, Harvard Medical School, Boston, MA 02115
| | - Mathias Pawlak
- Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Vijay K. Kuchroo
- Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Isaac Chiu
- Department of Immunology, Harvard Medical School, Boston, MA 02115
| | - David D. Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115
| | - Nikhil Sharma
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115
- Department of Molecular Pharmacology and Therapeutics, Department of Systems Biology, Columbia University, New York, NY
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13
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Takanami K, Morishita M, Sakamoto T, Sakamoto H. Chronic corticosterone exposure evokes itch hypersensitivity and sexual dysfunction in male rats: relationship between the two distinct gastrin-releasing peptide systems in the spinal cord. Gen Comp Endocrinol 2023; 339:114289. [PMID: 37094615 DOI: 10.1016/j.ygcen.2023.114289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/27/2023] [Accepted: 04/19/2023] [Indexed: 04/26/2023]
Abstract
In today's society, people are subjected to many social stressors, and excessive chronic stress causes functional disruption of the neuroendocrine system and many diseases. Although the exacerbation of atopic dermatitis with symptoms of itching and erectile dysfunction is induced by chronic stress, the details of the mechanisms are unknown. Here, we examined the effects of chronic stress on itch sensation and male sexual function at the behavioral and molecular levels, focusing on two distinct gastrin-releasing peptide (GRP) systems that independently regulate itch transmission, i.e., the somatosensory GRP system, and male sexual function, i.e., the lumbosacral autonomic GRP system, in the spinal cord. In a rat model of chronic stress induced by chronic corticosterone (CORT) administration, we observed increased plasma CORT concentrations, decreased body weight, and increased anxiety-like behavior, similar to that observed in humans. Chronic CORT exposure induced hypersensitivity to itch and increased the Grp mRNA level in the spinal somatosensory system, but there was no change in pain or tactile sensitivity. Antagonists of the somatosensory GRP receptor, an itch-specific mediator, suppressed itch hypersensitivity induced by chronic CORT exposure. In contrast, chronic CORT exposure decreased male sexual behavior, ejaculated semen volume, vesicular gland weight, and plasma testosterone levels. However, there were no effects on the expression of Grp mRNA or protein in the lumbosacral autonomic GRP system, which regulates male sexual function. In summary, chronic stress model rats showed itch hypersensitivity and impaired sexual function in males, and the involvement of the spinal GRP systems was apparent in itch hypersensitivity.
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Affiliation(s)
- Keiko Takanami
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan; Mouse Genomics Resources Laboratory, National Institute of Genetics, Yata, Mishima, Shizuoka 411-8540, Japan; Department of Environmental Health, Faculty of Human Life and Environmental Sciences, Nara Women's University, Kitauoya Nishimachi, Nara 630-8506, Japan.
| | - Makoto Morishita
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan
| | - Tatsuya Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan
| | - Hirotaka Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan
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14
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Liu Y, Cao C, Huang XP, Gumpper RH, Rachman MM, Shih SL, Krumm BE, Zhang S, Shoichet BK, Fay JF, Roth BL. Ligand recognition and allosteric modulation of the human MRGPRX1 receptor. Nat Chem Biol 2023; 19:416-422. [PMID: 36302898 DOI: 10.1038/s41589-022-01173-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/13/2022] [Indexed: 11/09/2022]
Abstract
The human MAS-related G protein-coupled receptor X1 (MRGPRX1) is preferentially expressed in the small-diameter primary sensory neurons and involved in the mediation of nociception and pruritus. Central activation of MRGPRX1 by the endogenous opioid peptide fragment BAM8-22 and its positive allosteric modulator ML382 has been shown to effectively inhibit persistent pain, making MRGPRX1 a promising target for non-opioid pain treatment. However, the activation mechanism of MRGPRX1 is still largely unknown. Here we report three high-resolution cryogenic electron microscopy structures of MRGPRX1-Gαq in complex with BAM8-22 alone, with BAM8-22 and ML382 simultaneously as well as with a synthetic agonist compound-16. These structures reveal the agonist binding mode for MRGPRX1 and illuminate the structural requirements for positive allosteric modulation. Collectively, our findings provide a molecular understanding of the activation and allosteric modulation of the MRGPRX1 receptor, which could facilitate the structure-based design of non-opioid pain-relieving drugs.
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Affiliation(s)
- Yongfeng Liu
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Can Cao
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Xi-Ping Huang
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Ryan H Gumpper
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Moira M Rachman
- Department of Pharmaceutical Sciences, University of California, San Francisco School of Medicine, San Francisco, CA, USA
| | - Sheng-Luen Shih
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Brian E Krumm
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Shicheng Zhang
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Brian K Shoichet
- Department of Pharmaceutical Sciences, University of California, San Francisco School of Medicine, San Francisco, CA, USA
| | - Jonathan F Fay
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
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15
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Chen O, He Q, Han Q, Furutani K, Gu Y, Olexa M, Ji RR. Mechanisms and treatments of neuropathic itch in a mouse model of lymphoma. J Clin Invest 2023; 133:160807. [PMID: 36520531 PMCID: PMC9927942 DOI: 10.1172/jci160807] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Our understanding of neuropathic itch is limited due to a lack of relevant animal models. Patients with cutaneous T cell lymphoma (CTCL) experience severe itching. Here, we characterize a mouse model of chronic itch with remarkable lymphoma growth, immune cell accumulation, and persistent pruritus. Intradermal CTCL inoculation produced time-dependent changes in nerve innervations in lymphoma-bearing skin. In the early phase (20 days), CTCL caused hyperinnervations in the epidermis. However, chronic itch was associated with loss of epidermal nerve fibers in the late phases (40 and 60 days). CTCL was also characterized by marked nerve innervations in mouse lymphoma. Blockade of C-fibers reduced pruritus at early and late phases, whereas blockade of A-fibers only suppressed late-phase itch. Intrathecal (i.t.) gabapentin injection reduced late-phase, but not early-phase, pruritus. IL-31 was upregulated in mouse lymphoma, whereas its receptor Il31ra was persistently upregulated in Trpv1-expressing sensory neurons in mice with CTCL. Intratumoral anti-IL-31 treatment effectively suppressed CTCL-induced scratching and alloknesis (mechanical itch). Finally, i.t. administration of a TLR4 antagonist attenuated pruritus in early and late phases and in both sexes. Collectively, we have established a mouse model of neuropathic and cancer itch with relevance to human disease. Our findings also suggest distinct mechanisms underlying acute, chronic, and neuropathic itch.
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Affiliation(s)
- Ouyang Chen
- Center for Translational Pain Medicine, Department of Anesthesiology,,Department of Cell Biology, and
| | - Qianru He
- Center for Translational Pain Medicine, Department of Anesthesiology
| | - Qingjian Han
- Center for Translational Pain Medicine, Department of Anesthesiology
| | - Kenta Furutani
- Center for Translational Pain Medicine, Department of Anesthesiology
| | - Yun Gu
- Center for Translational Pain Medicine, Department of Anesthesiology
| | - Madelynne Olexa
- Center for Translational Pain Medicine, Department of Anesthesiology
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology,,Department of Cell Biology, and,Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA
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16
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Granjon M, Doignon-Camus N, Popa-Roch M, Rohmer O. Neural empathic response to disability: An ERP study of prejudice. Biol Psychol 2023; 177:108507. [PMID: 36706863 DOI: 10.1016/j.biopsycho.2023.108507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 01/03/2023] [Accepted: 01/23/2023] [Indexed: 01/26/2023]
Abstract
While social neuroscience has already provided evidence for a deficit of affective empathy in racial prejudice, little is known about other less visible social categories when considered as an outgroup. We studied the process of empathy through event-related brain potentials (ERPs). We focused on the group "people with disabilities" as they are the target of a large amount of prejudice. Twenty-six participants performed a pain decision task. The mean amplitudes of N1, P2, N2-N3 and P3 components were recorded. Our results are consistent with previous work on prejudice, showing that the pain detection is modulated by group membership (with disabilities vs. without disabilities) on N2-N3, suggesting a better neural decoding of pain vs. non-pain in the without-disability condition. Critically, no effect of early sensory components (N1, P2) was found, and P3 was not moderated by disability. These findings indicate a different time course of empathic responses depending on the condition, suggesting that people with disabilities trigger specific empathic responses. Our results contribute to disentangling perceptual processes from affective empathy reactions.
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Affiliation(s)
- Marine Granjon
- University of Strasbourg, Laboratoire de Psychologie des Cognitions, France.
| | - Nadège Doignon-Camus
- University of Strasbourg, Laboratoire Interuniversitaire des Sciences de l'Education et de la Communication, France
| | - Maria Popa-Roch
- University of Strasbourg, Laboratoire Interuniversitaire des Sciences de l'Education et de la Communication, France
| | - Odile Rohmer
- University of Strasbourg, Laboratoire de Psychologie des Cognitions, France
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17
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Kaneko T, Kuwaki T. The opposite roles of orexin neurons in pain and itch neural processing. Peptides 2023; 160:170928. [PMID: 36566840 DOI: 10.1016/j.peptides.2022.170928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 12/17/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022]
Abstract
Pain and itch are antagonistically regulated sensations; pain suppresses itch, and inhibition of pain enhances itch. Understanding the central neural circuit of antagonistic regulation between pain and itch is required to develop new therapeutics better to manage these two feelings in a clinical situation. However, evidence of the neural mechanism underlying the pain-itch interaction in the central nervous system (CNS) is still insufficient. To pave the way for this research area, our laboratory has focused on orexin (ORX) producing neurons in the hypothalamus, which is known as a master switch that induces various defense responses when animals face a stressful environment. This review article summarized the previous evidence and our latest findings to argue the neural regulation between pain and itch and the bidirectional roles of ORX neurons in processing these two sensations. i.e., pain relief and itch exacerbation. Further, we discussed the possible neural circuit mechanism for the opposite controlling of pain and itch by ORX neurons. Focusing on the roles of ORX neurons would provide a new perspective to understand the antagonistic regulation of pain and itch in CNS.
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Affiliation(s)
- Tatsuroh Kaneko
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.
| | - Tomoyuki Kuwaki
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan
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18
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Vieillard J, Franck MCM, Hartung S, Jakobsson JET, Ceder MM, Welsh RE, Lagerström MC, Kullander K. Adult spinal Dmrt3 neurons receive direct somatosensory inputs from ipsi- and contralateral primary afferents and from brainstem motor nuclei. J Comp Neurol 2023; 531:5-24. [PMID: 36214727 PMCID: PMC9828095 DOI: 10.1002/cne.25405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 08/15/2022] [Accepted: 08/22/2022] [Indexed: 01/12/2023]
Abstract
In the spinal cord, sensory-motor circuits controlling motor activity are situated in the dorso-ventral interface. The neurons identified by the expression of the transcription factor Doublesex and mab-3 related transcription factor 3 (Dmrt3) have previously been associated with the coordination of locomotion in horses (Equus caballus, Linnaeus, 1758), mice (Mus musculus, Linnaeus, 1758), and zebrafish (Danio rerio, F. Hamilton, 1822). Based on earlier studies, we hypothesized that, in mice, these neurons may be positioned to receive sensory and central inputs to relay processed commands to motor neurons. Thus, we investigated the presynaptic inputs to spinal Dmrt3 neurons using monosynaptic retrograde replication-deficient rabies tracing. The analysis showed that lumbar Dmrt3 neurons receive inputs from intrasegmental neurons, and intersegmental neurons from the cervical, thoracic, and sacral segments. Some of these neurons belong to the excitatory V2a interneurons and to plausible Renshaw cells, defined by the expression of Chx10 and calbindin, respectively. We also found that proprioceptive primary sensory neurons of type Ia2, Ia3, and Ib, defined by the expression of calbindin, calretinin, and Brn3c, respectively, provide presynaptic inputs to spinal Dmrt3 neurons. In addition, we demonstrated that Dmrt3 neurons receive inputs from brain areas involved in motor regulation, including the red nucleus, primary sensory-motor cortex, and pontine nuclei. In conclusion, adult spinal Dmrt3 neurons receive inputs from motor-related brain areas as well as proprioceptive primary sensory neurons and have been shown to connect directly to motor neurons. Dmrt3 neurons are thus positioned to provide sensory-motor control and their connectivity is suggestive of the classical reflex pathways present in the spinal cord.
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Affiliation(s)
- Jennifer Vieillard
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Marina C. M. Franck
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden,Present address: Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
| | - Sunniva Hartung
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Jon E. T. Jakobsson
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Mikaela M. Ceder
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Robert E. Welsh
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Malin C. Lagerström
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Klas Kullander
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
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19
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Grpr expression defines a population of superficial dorsal horn vertical cells that have a role in both itch and pain. Pain 2023; 164:149-170. [PMID: 35543635 PMCID: PMC9756441 DOI: 10.1097/j.pain.0000000000002677] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/06/2022] [Indexed: 01/09/2023]
Abstract
ABSTRACT Neurons in the superficial dorsal horn that express the gastrin-releasing peptide receptor (GRPR) are strongly implicated in spinal itch pathways. However, a recent study reported that many of these correspond to vertical cells, a population of interneurons that are believed to transmit nociceptive information. In this study, we have used a GRPR CreERT2 mouse line to identify and target cells that possess Grpr mRNA. We find that the GRPR cells are highly concentrated in lamina I and the outer part of lamina II, that they are all glutamatergic, and that they account for ∼15% of the excitatory neurons in the superficial dorsal horn. We had previously identified 6 neurochemically distinct excitatory interneuron populations in this region based on neuropeptide expression and the GRPR cells are largely separate from these, although they show some overlap with cells that express substance P. Anatomical analysis revealed that the GRPR neurons are indeed vertical cells, and that their axons target each other, as well as arborising in regions that contain projection neurons: lamina I, the lateral spinal nucleus, and the lateral part of lamina V. Surprisingly, given the proposed role of GRPR cells in itch, we found that most of the cells received monosynaptic input from Trpv1-expressing (nociceptive) afferents, that the majority responded to noxious and pruritic stimuli, and that chemogenetically activating them resulted in pain-related and itch-related behaviours. Together, these findings suggest that the GRPR cells are involved in spinal cord circuits that underlie both pain and itch.
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20
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Katayama Y, Miura A, Sakamoto T, Takanami K, Sakamoto H. Footedness for scratching itchy eyes in rodents. Proc Biol Sci 2022; 289:20221126. [PMID: 36259204 PMCID: PMC9579771 DOI: 10.1098/rspb.2022.1126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 09/21/2022] [Indexed: 11/12/2022] Open
Abstract
The neural bases of itchy eye transmission remain unclear compared with those involved in body itch. Here, we show in rodents that the gastrin-releasing peptide receptor (GRPR) of the trigeminal sensory system is involved in the transmission of itchy eyes. Interestingly, we further demonstrate a difference in scratching behaviour between the left and right hindfeet in rodents; histamine instillation into the conjunctival sac of both eyes revealed right-foot biased laterality in the scratching movements. Unilateral histamine instillation specifically induced neural activation in the ipsilateral sensory pathway, with no significant difference between the activations following left- and right-eye instillations. Thus, the behavioural laterality is presumably due to right-foot preference in rodents. Genetically modified rats with specific depletion of Grpr-expressing neurons in the trigeminal sensory nucleus caudalis of the medulla oblongata exhibited fewer and shorter histamine-induced scratching movements than controls and eliminated the footedness. These results taken together indicate that the Grpr-expressing neurons are required for the transmission of itch sensation from the eyes, but that foot preference is generated centrally. These findings could open up a new field of research on the mechanisms of the laterality in vertebrates and also offer new potential therapeutic approaches to refractory pruritic eye disorders.
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Affiliation(s)
- Yukitoshi Katayama
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan
| | - Ayane Miura
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan
- Department of Biology, Faculty of Science, Okayama University, 3-1-1 Kita-ku, Tsushimanaka, Okayama 700-8530, Japan
| | - Tatsuya Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan
| | - Keiko Takanami
- Mouse Genomics Resources Laboratory, National Institute of Genetics, Yata, Mishima, Shizuoka 411-8540, Japan
- Department of Environmental Health, Faculty of Human Life and Environmental Sciences, Nara Women's University, Kitauoya Nishimachi, Nara 630-8506, Japan
| | - Hirotaka Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama 701-4303, Japan
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21
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Critical Players and Therapeutic Targets in Chronic Itch. Int J Mol Sci 2022; 23:ijms23179935. [PMID: 36077340 PMCID: PMC9456029 DOI: 10.3390/ijms23179935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/28/2022] [Accepted: 08/29/2022] [Indexed: 12/04/2022] Open
Abstract
Chronic itch is one of the most prominent clinical characteristics of diverse systematic diseases. It is a devastating sensation in pathological diseases. Despite its importance, there are no FDA-labelled drugs specifically geared toward chronic itch. The associated complex pathogenesis and diverse causes escalate chronic itch to being one of the top challenges in healthcare. Humanized antibodies against IL-13, IL-4, and IL-31 proved effective in treatment of itch-associated atopic dermatitis but remain to be validated in chronic itch. There are still no satisfactory anti-itch therapeutics available toward itch-related neuropeptides including GRP, BNP, SST, CGRP, and SP. The newly identified potential itch targets including OSM, NMB, glutamate, periostin, and Serpin E1 have opened new avenues for therapeutic development. Proof-of-principle studies have been successfully performed on antagonists against these proteins and their receptors in itch treatment in animal models. Their translational interventions in humans need to be evaluated. It is of great importance to summarize and compare the newly emerging knowledge on chronic itch and its pathways to promote the development of novel anti-itch therapeutics. The goal of this review is to analyze the different physiologies and pathophysiologies of itch mediators, whilst assessing their suitability as new targets and discussing future therapeutic development.
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22
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Kaneko T, Kuwaki T, Kashiwadani H. Hypothalamic orexinergic neurons modulate pain and itch in an opposite way: pain relief and itch exacerbation. J Physiol Sci 2022; 72:21. [PMID: 35996084 DOI: 10.1186/s12576-022-00846-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 08/07/2022] [Indexed: 11/10/2022]
Abstract
Pain and itch are recognized as antagonistic sensations; pain suppresses itch and inhibition of pain generates itch. There is still a lack of evidence about the neural mechanism of the interaction between pain and itch in the central nervous system. In this study, we focused on the orexin (ORX) neurons in the lateral hypothalamus (LH), which mediate various "defense responses" when animals confront stressors. We found that the scratching behaviors induced by the pruritogen were significantly suppressed in ORX-neuron-ablated (ORX-abl) mice. The exaggerated pain behavior and attenuated itch behavior observed in ORX-abl mice indicated that ORX neurons modulate pain and itch in an opposite way, i.e., pain relief and itch exacerbation. In addition, most of the ORX neurons responded to both pain and itch input. Our results suggest that ORX neurons inversely regulate pain- and itch-related behaviors, which could be understood as a defense response to cope with stress environment.
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Affiliation(s)
- Tatsuroh Kaneko
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, 890-8544, Japan
| | - Tomoyuki Kuwaki
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, 890-8544, Japan
| | - Hideki Kashiwadani
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, 890-8544, Japan.
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23
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Jiang S, Wang YS, Zheng XX, Zhao SL, Wang Y, Sun L, Chen PH, Zhou Y, Tin C, Li HL, Sui JF, Wu GY. Itch-specific neurons in the ventrolateral orbital cortex selectively modulate the itch processing. SCIENCE ADVANCES 2022; 8:eabn4408. [PMID: 35905177 PMCID: PMC9337765 DOI: 10.1126/sciadv.abn4408] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 06/16/2022] [Indexed: 05/31/2023]
Abstract
Itch is a cutaneous sensation that is critical in driving scratching behavior. The long-standing question of whether there are specific neurons for itch modulation inside the brain remains unanswered. Here, we report a subpopulation of itch-specific neurons in the ventrolateral orbital cortex (VLO) that is distinct from the pain-related neurons. Using a Tet-Off cellular labeling system, we showed that local inhibition or activation of these itch-specific neurons in the VLO significantly suppressed or enhanced itch-induced scratching, respectively, whereas the intervention did not significantly affect pain. Conversely, suppression or activation of pain-specific neurons in the VLO significantly affected pain but not itch. Moreover, fiber photometry and immunofluorescence verified that these itch- and pain-specific neurons are distinct in their functional activity and histological location. In addition, the downstream targets of itch- and pain-specific neurons were different. Together, the present study uncovers an important subpopulation of neurons in the VLO that specifically modulates itch processing.
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Affiliation(s)
- Shan Jiang
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Yi-Song Wang
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Xiao-Xia Zheng
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Shan-Lan Zhao
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Yi Wang
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Lin Sun
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Peng-Hui Chen
- Department of Neurobiology, Army Medical University, Chongqing 400038, China
| | - Yi Zhou
- Department of Neurobiology, Army Medical University, Chongqing 400038, China
| | - Chung Tin
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, SAR, People’s Republic of China
| | - Hong-Li Li
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Jian-Feng Sui
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Guang-Yan Wu
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
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24
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Hu L, Jiang GY, Wang YP, Hu ZB, Zhou BY, Zhang L, Song NN, Huang Y, Chai GD, Chen JY, Lang B, Xu L, Liu JL, Li Y, Wang QX, Ding YQ. The role of PTEN in primary sensory neurons in processing itch and thermal information in mice. Cell Rep 2022; 39:110724. [PMID: 35443189 DOI: 10.1016/j.celrep.2022.110724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 03/03/2022] [Accepted: 03/30/2022] [Indexed: 12/01/2022] Open
Abstract
PTEN is known as a tumor suppressor and plays essential roles in brain development. Here, we report that PTEN in primary sensory neurons is involved in processing itch and thermal information in adult mice. Deletion of PTEN in the dorsal root ganglia (DRG) is achieved in adult Drg11-CreER: PTENflox/flox (PTEN CKO) mice with oral administration of tamoxifen, and CKO mice develop pathological itch and elevated itch responses on exposure to various pruritogens. PTEN deletion leads to ectopic expression of TRPV1 and MrgprA3 in IB4+ non-peptidergic DRG neurons, and the TRPV1 is responsive to capsaicin. Importantly, the elevated itch responses are no longer present in Drg11-CreER: PTENflox/flox: TRPV1flox/flox (PTEN: TRPV1 dCKO) mice. In addition, thermal stimulation is enhanced in PTEN CKO mice but blunted in dCKO mice. PTEN-involved regulation of itch-related gene expression in DRG neurons provides insights for understanding molecular mechanism of itch and thermal sensation at the spinal level.
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Affiliation(s)
- Ling Hu
- Department of Laboratory Animal Science, Fudan University, Shanghai 200032, China; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China; Key Laboratory of Arrhythmias, Ministry of Education, East Hospital, and Department of Anatomy and Neurobiology, Tongji University School of Medicine, Shanghai 200092, China
| | - Guan-Yu Jiang
- Key Laboratory of Arrhythmias, Ministry of Education, East Hospital, and Department of Anatomy and Neurobiology, Tongji University School of Medicine, Shanghai 200092, China
| | - Ying-Ping Wang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
| | - Zhi-Bin Hu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | - Bing-Yao Zhou
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | - Lei Zhang
- Key Laboratory of Arrhythmias, Ministry of Education, East Hospital, and Department of Anatomy and Neurobiology, Tongji University School of Medicine, Shanghai 200092, China
| | - Ning-Ning Song
- Department of Laboratory Animal Science, Fudan University, Shanghai 200032, China; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | - Ying Huang
- Department of Laboratory Animal Science, Fudan University, Shanghai 200032, China
| | - Guo-Dong Chai
- Department of Anesthesiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Jia-Yin Chen
- Department of Laboratory Animal Science, Fudan University, Shanghai 200032, China; Key Laboratory of Arrhythmias, Ministry of Education, East Hospital, and Department of Anatomy and Neurobiology, Tongji University School of Medicine, Shanghai 200092, China
| | - Bing Lang
- Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Lin Xu
- Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Jun-Ling Liu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
| | - Yong Li
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
| | - Qing-Xiu Wang
- Department of Anesthesiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
| | - Yu-Qiang Ding
- Department of Laboratory Animal Science, Fudan University, Shanghai 200032, China; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China; Key Laboratory of Arrhythmias, Ministry of Education, East Hospital, and Department of Anatomy and Neurobiology, Tongji University School of Medicine, Shanghai 200092, China.
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25
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Ádám D, Arany J, Tóth KF, Tóth BI, Szöllősi AG, Oláh A. Opioidergic Signaling-A Neglected, Yet Potentially Important Player in Atopic Dermatitis. Int J Mol Sci 2022; 23:4140. [PMID: 35456955 PMCID: PMC9027603 DOI: 10.3390/ijms23084140] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 02/04/2023] Open
Abstract
Atopic dermatitis (AD) is one of the most common skin diseases, the prevalence of which is especially high among children. Although our understanding about its pathogenesis has substantially grown in recent years, and hence, several novel therapeutic targets have been successfully exploited in the management of the disease, we still lack curative treatments for it. Thus, there is an unmet societal demand to identify further details of its pathogenesis to thereby pave the way for novel therapeutic approaches with favorable side effect profiles. It is commonly accepted that dysfunction of the complex cutaneous barrier plays a central role in the development of AD; therefore, the signaling pathways involved in the regulation of this quite complex process are likely to be involved in the pathogenesis of the disease and can provide novel, promising, yet unexplored therapeutic targets. Thus, in the current review, we aim to summarize the available potentially AD-relevant data regarding one such signaling pathway, namely cutaneous opioidergic signaling.
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Affiliation(s)
- Dorottya Ádám
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (D.Á.); (J.A.); (K.F.T.); (B.I.T.)
- Doctoral School of Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - József Arany
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (D.Á.); (J.A.); (K.F.T.); (B.I.T.)
- Doctoral School of Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Kinga Fanni Tóth
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (D.Á.); (J.A.); (K.F.T.); (B.I.T.)
- Doctoral School of Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Balázs István Tóth
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (D.Á.); (J.A.); (K.F.T.); (B.I.T.)
| | - Attila Gábor Szöllősi
- Department of Immunology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary;
| | - Attila Oláh
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (D.Á.); (J.A.); (K.F.T.); (B.I.T.)
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26
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Saeki A, Yamanaka H, Kobayashi K, Okubo M, Noguchi K. Analgesic effect of gastrin-releasing peptide in the dorsal horn. Mol Pain 2022; 18:17448069221108965. [PMID: 35815426 PMCID: PMC9277428 DOI: 10.1177/17448069221108965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Itch and pain are both unpleasant, but they are discrete sensations. Both of these
sensations are transmitted by C-fibers and processed in laminae I-II of the dorsal horn.
To examine whether pruriception modulates pain, we first confirmed the activation of cells
in the itch-related circuits that were positive for gastrin-releasing peptide (GRP) and
GRP receptor (GRPR) using a paw formalin injection model. This pain model with typical
biphasic pain behavior increased c-Fos but did not affect the expressions of
GRP and GRPR mRNAs in the dorsal horn. Using c-Fos
expression as a marker for activated cells, we confirmed that formalin injection increased
the number of cells double-labeled for c-Fos and GRP or GRPR in the dorsal horn. The
emergence of these neurons indicates the activation of itch-related circuits by acute pain
signals. The effect of an antagonist for a GRPR was examined in the paw formalin injection
model. Intrathecal chronic antagonization of spinal GRPR enhanced the onset of phase II of
paw formalin injection-induced pain behavior. Exogenous intrathecal GRP infusion to the
paw-formalin injection model not only showed significant reduction of pain behavior but
also increased c-Fos in the inhibitory neurons in the dorsal horn. The anti-nociceptive
effect of spinal GRP infusion was observed in the peripheral inflammation model (complete
Freund’s adjuvant injection model). In this study we suggest that painful stimuli
activated itch-related neuronal circuits and uncovered the spinal activation of the
itch-induced analgesic effect on acute and established inflammatory pain.
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Affiliation(s)
- Ayano Saeki
- Department of Anatomy and Neuroscience, Faculty of Medicine, 12818Hyogo Medical University, Nishinomiya, Hyogo, Japan.,Department of Anesthesiology and Pain Medicine, Faculty of Medicine, 12818Hyogo Medical University, Nishinomiya, Hyogo, Japan
| | - Hiroki Yamanaka
- Department of Anatomy and Neuroscience, Faculty of Medicine, 12818Hyogo Medical University, Nishinomiya, Hyogo, Japan
| | - Kimiko Kobayashi
- Department of Anatomy and Neuroscience, Faculty of Medicine, 12818Hyogo Medical University, Nishinomiya, Hyogo, Japan
| | - Masamichi Okubo
- Department of Anatomy and Neuroscience, Faculty of Medicine, 12818Hyogo Medical University, Nishinomiya, Hyogo, Japan
| | - Koichi Noguchi
- Department of Anatomy and Neuroscience, Faculty of Medicine, 12818Hyogo Medical University, Nishinomiya, Hyogo, Japan
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27
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Szöllősi AG, Oláh A, Lisztes E, Griger Z, Tóth BI. Pruritus: A Sensory Symptom Generated in Cutaneous Immuno-Neuronal Crosstalk. Front Pharmacol 2022; 13:745658. [PMID: 35321329 PMCID: PMC8937025 DOI: 10.3389/fphar.2022.745658] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 02/07/2022] [Indexed: 12/21/2022] Open
Abstract
Pruritus or itch generated in the skin is one of the most widespread symptoms associated with various dermatological and systemic (immunological) conditions. Although many details about the molecular mechanisms of the development of both acute and chronic itch were uncovered in the last 2 decades, our understanding is still incomplete and the clinical management of pruritic conditions is one of the biggest challenges in daily dermatological practice. Recent research revealed molecular interactions between pruriceptive sensory neurons and surrounding cutaneous cell types including keratinocytes, as well as resident and transient cells of innate and adaptive immunity. Especially in inflammatory conditions, these cutaneous cells can produce various mediators, which can contribute to the excitation of pruriceptive sensory fibers resulting in itch sensation. There also exists significant communication in the opposite direction: sensory neurons can release mediators that maintain an inflamed, pruritic tissue-environment. In this review, we summarize the current knowledge about the sensory transduction of pruritus detailing the local intercellular interactions that generate itch. We especially emphasize the role of various pruritic mediators in the bidirectional crosstalk between cutaneous non-neuronal cells and sensory fibers. We also list various dermatoses and immunological conditions associated with itch, and discuss the potential immune-neuronal interactions promoting the development of pruritus in the particular diseases. These data may unveil putative new targets for antipruritic pharmacological interventions.
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Affiliation(s)
- Attila Gábor Szöllősi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Attila Oláh
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Erika Lisztes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zoltán Griger
- Division of Clinical Immunology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs István Tóth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- *Correspondence: Balázs István Tóth,
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28
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Guo F, Du Y, Qu FH, Lin SD, Chen Z, Zhang SH. Dissecting the Neural Circuitry for Pain Modulation and Chronic Pain: Insights from Optogenetics. Neurosci Bull 2022; 38:440-452. [PMID: 35249185 PMCID: PMC9068856 DOI: 10.1007/s12264-022-00835-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 11/25/2021] [Indexed: 12/17/2022] Open
Abstract
Pain is an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage. The processing of pain involves complicated modulation at the levels of the periphery, spinal cord, and brain. The pathogenesis of chronic pain is still not fully understood, which makes the clinical treatment challenging. Optogenetics, which combines optical and genetic technologies, can precisely intervene in the activity of specific groups of neurons and elements of the related circuits. Taking advantage of optogenetics, researchers have achieved a body of new findings that shed light on the cellular and circuit mechanisms of pain transmission, pain modulation, and chronic pain both in the periphery and the central nervous system. In this review, we summarize recent findings in pain research using optogenetic approaches and discuss their significance in understanding the pathogenesis of chronic pain.
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Affiliation(s)
- Fang Guo
- Department of Pharmacology and Department of Anesthesiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yu Du
- Department of Pharmacology and Department of Anesthesiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Feng-Hui Qu
- Department of Pharmacology and Department of Anesthesiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Shi-Da Lin
- Department of Pharmacology and Department of Anesthesiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Zhong Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China.
| | - Shi-Hong Zhang
- Department of Pharmacology and Department of Anesthesiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.
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29
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Glutamate in primary afferents is required for itch transmission. Neuron 2022; 110:809-823.e5. [PMID: 34986325 PMCID: PMC8898340 DOI: 10.1016/j.neuron.2021.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/21/2021] [Accepted: 12/06/2021] [Indexed: 12/13/2022]
Abstract
Whether glutamate or itch-selective neurotransmitters are used to confer itch specificity is still under debate. We focused on an itch-selective population of primary afferents expressing MRGPRA3, which highly expresses Vglut2 and the neuropeptide neuromedin B (Nmb), to investigate this question. Optogenetic stimulation of MRGPRA3+ afferents triggers scratching and other itch-related avoidance behaviors. Using a combination of optogenetics, spinal cord slice recordings, Vglut2 conditional knockout mice, and behavior assays, we showed that glutamate is essential for MRGPRA3+ afferents to transmit itch. We further demonstrated that MRGPRA3+ afferents form monosynaptic connections with both NMBR+ and NMBR- neurons and that NMB and glutamate together can enhance the activity of NMBR+ spinal DH neurons. Moreover, Nmb in MRGPRA3+ afferents and NMBR+ DH neurons are required for chloroquine-induced scratching. Together, our results establish a new model in which glutamate is an essential neurotransmitter in primary afferents for itch transmission, whereas NMB signaling enhances its activities.
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Larsson M, Nagi SS. Role of C-tactile fibers in pain modulation: animal and human perspectives. Curr Opin Behav Sci 2022. [DOI: 10.1016/j.cobeha.2021.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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31
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Yun S, Koh CS, Seo J, Shim S, Park M, Jung HH, Eom K, Chang JW, Kim SJ. A Fully Implantable Miniaturized Liquid Crystal Polymer (LCP)-Based Spinal Cord Stimulator for Pain Control. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22020501. [PMID: 35062462 PMCID: PMC8778878 DOI: 10.3390/s22020501] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/04/2022] [Accepted: 01/06/2022] [Indexed: 05/09/2023]
Abstract
Spinal cord stimulation is a therapy to treat the severe neuropathic pain by suppressing the pain signal via electrical stimulation of the spinal cord. The conventional metal packaged and battery-operated implantable pulse generator (IPG) produces electrical pulses to stimulate the spinal cord. Despite its stable operation after implantation, the implantation site is limited due to its bulky size and heavy weight. Wireless communications including wireless power charging is also restricted, which is mainly attributed to the electromagnetic shielding of the metal package. To overcome these limitations, here, we developed a fully implantable miniaturized spinal cord stimulator based on a biocompatible liquid crystal polymer (LCP). The fabrication of electrode arrays in the LCP substrate and monolithically encapsulating the circuitries using LCP packaging reduces the weight (0.4 g) and the size (the width, length, and thickness are 25.3, 9.3, and 1.9 mm, respectively). An inductive link was utilized to wirelessly transfer the power and the data to implanted circuitries to generate the stimulus pulse. Prior to implantation of the device, operation of the pulse generator was evaluated, and characteristics of stimulation electrode such as an electrochemical impedance spectroscopy (EIS) were measured. The LCP-based spinal cord stimulator was implanted into the spared nerve injury rat model. The degree of pain suppression upon spinal cord stimulation was assessed via the Von Frey test where the mechanical stimulation threshold was evaluated by monitoring the paw withdrawal responses. With no spinal cord stimulation, the mechanical stimulation threshold was observed as 1.47 ± 0.623 g, whereas the stimulation threshold was increased to 12.7 ± 4.00 g after spinal cord stimulation, confirming the efficacy of pain suppression via electrical stimulation of the spinal cord. This LCP-based spinal cord stimulator opens new avenues for the development of a miniaturized but still effective spinal cord stimulator.
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Affiliation(s)
- Seunghyeon Yun
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul 08826, Korea; (S.Y.); (J.S.); (S.S.); (S.J.K.)
| | - Chin Su Koh
- Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 03722, Korea; (C.S.K.); (M.P.); (H.H.J.)
| | - Jungmin Seo
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul 08826, Korea; (S.Y.); (J.S.); (S.S.); (S.J.K.)
| | - Shinyong Shim
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul 08826, Korea; (S.Y.); (J.S.); (S.S.); (S.J.K.)
| | - Minkyung Park
- Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 03722, Korea; (C.S.K.); (M.P.); (H.H.J.)
| | - Hyun Ho Jung
- Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 03722, Korea; (C.S.K.); (M.P.); (H.H.J.)
| | - Kyungsik Eom
- Department of Electronics Engineering, College of Engineering, Pusan National University, Busan 46241, Korea
- Correspondence: (K.E.); (J.W.C.)
| | - Jin Woo Chang
- Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 03722, Korea; (C.S.K.); (M.P.); (H.H.J.)
- Correspondence: (K.E.); (J.W.C.)
| | - Sung June Kim
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul 08826, Korea; (S.Y.); (J.S.); (S.S.); (S.J.K.)
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Abstract
The opioid peptides and their receptors have been linked to multiple key biological processes in the nervous system. Here we review the functions of the kappa opioid receptor (KOR) and its endogenous agonists dynorphins (Goldstein A, Tachibana S, Lowney LI, Hunkapiller M, Hood L, Proc Natl Acad Sci U S A 76:6666-6670, 1979) in modulating itch and pain (nociception). Specifically, we discuss their roles relative to recent findings that tell us more about the cells and circuits which are impacted by this opioid and its receptor and present reanalysis of single-cell sequencing data showing the expression profiles of these molecules. Since the KOR is relatively specifically activated by peptides derived from the prodynorphin gene and other opioid peptides that show lower affinities, this will be the only interactions we consider (Chavkin C, Goldstein A, Nature 291:591-593, 1981; Chavkin C, James IF, Goldstein A, Science 215:413-415, 1982), although it was noted that at higher doses peptides other than dynorphins might stimulate KOR (Lai J, Luo MC, Chen Q, Ma S, Gardell LR, Ossipov MH, Porreca F, Nat Neurosci 9:1534-1540, 2006). This review has been organized based on anatomy with each section describing the effect of the kappa opioid system in a specific location but let us not forget that most of these circuits are interconnected and are therefore interdependent.
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Affiliation(s)
- Pang-Yen Tseng
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research/NIH, Bethesda, MD, USA
| | - Mark A Hoon
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research/NIH, Bethesda, MD, USA.
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33
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Tseng PY, Hoon MA. Interactions of the Neuro‒Immune‒Stromal Triad in Itch. J Invest Dermatol 2022; 142:42-46. [PMID: 34662564 PMCID: PMC8688333 DOI: 10.1016/j.jid.2021.08.443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/02/2021] [Accepted: 08/09/2021] [Indexed: 01/03/2023]
Abstract
This review focuses on recent advances in understanding the mechanisms involved in itch signaling in the skin and how these new findings fit into the wider picture of the expression of itch mediators and their receptors in the dermal layer. Because at present studies mostly concentrate on single cellular compartments (e.g., neural alone), we suggest that they may miss important interactions with other compartments. Therefore, to fully appreciate pruritus, we propose that studies should consider (e.g., using transcriptomic information) signal transmission within the entire neuro‒immune‒stromal triad.
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Affiliation(s)
- Pang-Yen Tseng
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research/NIH, 35 Convent Drive, Bethesda, MD 20892, USA
| | - Mark A. Hoon
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research/NIH, 35 Convent Drive, Bethesda, MD 20892, USA.,To whom correspondence should be addressed,
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34
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Zhang F, Wu LB, Yu Q, Wang MJ, Zeng XL, Wei XT, Wu ZJ, Cai RL, Hu L. Neurotropic Viruses as a Tool for Neural Circuit-Tracing. NEUROCHEM J+ 2021. [DOI: 10.1134/s1819712421040176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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35
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Xu Q, Ford NC, He S, Huang Q, Anderson M, Chen Z, Yang F, Crawford LK, Caterina MJ, Guan Y, Dong X. Astrocytes contribute to pain gating in the spinal cord. SCIENCE ADVANCES 2021; 7:eabi6287. [PMID: 34730998 PMCID: PMC8565904 DOI: 10.1126/sciadv.abi6287] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Various pain therapies have been developed on the basis of the gate control theory of pain, which postulates that nonpainful sensory inputs mediated by large-diameter afferent fibers (Aβ-fibers) can attenuate noxious signals relayed to the brain. To date, this theory has focused only on neuronal mechanisms. Here, we identified an unprecedented function of astrocytes in the gating of nociceptive signals transmitted by neurokinin 1 receptor–positive (NK1R+) projection neurons in the spinal cord. Electrical stimulation of peripheral Aβ-fibers in naïve mice activated spinal astrocytes, which in turn induced long-term depression (LTD) in NK1R+ neurons and antinociception through activation of endogenous adenosinergic mechanisms. Suppression of astrocyte activation by pharmacologic, chemogenetic, and optogenetic manipulations blocked the induction of LTD in NK1R+ neurons and pain inhibition by Aβ-fiber stimulation. Collectively, our study introduces astrocytes as an important component of pain gating by activation of Aβ-fibers, which thus exert nonneuronal control of pain.
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Affiliation(s)
- Qian Xu
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Neil C. Ford
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shaoqiu He
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Qian Huang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael Anderson
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zhiyong Chen
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Fei Yang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - LaTasha K. Crawford
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael J. Caterina
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurological Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurological Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurological Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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36
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Abstract
Itch is one of the most primal sensations, being both ubiquitous and important for the well-being of animals. For more than a century, a desire to understand how itch is encoded by the nervous system has prompted the advancement of many theories. Within the past 15 years, our understanding of the molecular and neural mechanisms of itch has undergone a major transformation, and this remarkable progress continues today without any sign of abating. Here I describe accumulating evidence that indicates that itch is distinguished from pain through the actions of itch-specific neuropeptides that relay itch information to the spinal cord. According to this model, classical neurotransmitters transmit, inhibit and modulate itch information in a context-, space- and time-dependent manner but do not encode itch specificity. Gastrin-releasing peptide (GRP) is proposed to be a key itch-specific neuropeptide, with spinal neurons expressing GRP receptor (GRPR) functioning as a key part of a convergent circuit for the conveyance of peripheral itch information to the brain.
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37
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Ran C, Kamalani GNA, Chen X. Modality-Specific Modulation of Temperature Representations in the Spinal Cord after Injury. J Neurosci 2021; 41:8210-8219. [PMID: 34408066 PMCID: PMC8482863 DOI: 10.1523/jneurosci.1104-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/06/2021] [Accepted: 08/11/2021] [Indexed: 12/25/2022] Open
Abstract
Different types of tissue injury, such as inflammatory and neuropathic conditions, cause modality-specific alternations on temperature perception. There are profound changes in peripheral sensory neurons after injury, but how patterned neuronal activities in the CNS encode injury-induced sensitization to temperature stimuli is largely unknown. Using in vivo calcium imaging and mouse genetics, we show that formalin- and prostaglandin E2-induced inflammation dramatically increase spinal responses to heating and decrease responses to cooling in male and female mice. The reduction of cold response is largely eliminated on ablation of TRPV1-expressing primary sensory neurons, indicating a crossover inhibition of cold response from the hyperactive heat inputs in the spinal cord. Interestingly, chemotherapy medication oxaliplatin can rapidly increase spinal responses to cooling and suppress responses to heating. Together, our results suggest a push-pull mechanism in processing cold and heat inputs and reveal a synergic mechanism to shift thermosensation after injury.SIGNIFICANCE STATEMENT In this paper, we combine our novel in vivo spinal cord two-photon calcium imaging, mouse genetics, and persistent pain models to study how tissue injury alters the sensation of temperature. We discover modality-specific changes of spinal temperature responses in different models of injury. Chemotherapy medication oxaliplatin leads to cold hypersensitivity and heat hyposensitivity. By contrast, inflammation increases heat sensitivity and decreases cold sensitivity. This decrease in cold sensitivity results from the stronger crossover inhibition from the hyperactive heat inputs. Our work reveals the bidirectional change of thermosensitivity by injury and suggests that the crossover inhibitory circuit underlies the shifted thermosensation, providing a mechanism to the biased perception toward a unique thermal modality that was observed clinically in chronic pain patients.
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Affiliation(s)
- Chen Ran
- Department of Biology, Stanford University, Stanford, California 94305
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | | | - Xiaoke Chen
- Department of Biology, Stanford University, Stanford, California 94305
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38
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Misery L, Brenaut E, Pierre O, Le Garrec R, Gouin O, Lebonvallet N, Abasq-Thomas C, Talagas M, Le Gall-Ianotto C, Besner-Morin C, Fluhr JW, Leven C. Chronic itch: emerging treatments following new research concepts. Br J Pharmacol 2021; 178:4775-4791. [PMID: 34463358 DOI: 10.1111/bph.15672] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 11/29/2022] Open
Abstract
Until recently, itch pathophysiology was poorly understood and treatments were poorly effective in relieving itch. Current progress in our knowledge of the itch processing, the numerous mediators and receptors involved has led to a large variety of possible therapeutic pathways. Currently, inhibitors of IL-31, IL-4/13, NK1 receptors, opioids and cannabinoids, JAK, PDE4 or TRP are the main compounds involved in clinical trials. However, many new targets, such as Mas-related GPCRs and unexpected new pathways need to be also explored.
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Affiliation(s)
- Laurent Misery
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | - Emilie Brenaut
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | | | | | - Olivier Gouin
- LIEN, Univ Brest, Brest, France.,INSERM UMR 1163, Laboratory of Genetic Skin Diseases, Imagine Institute, Paris, France.,University of Paris, Paris, France
| | | | - Claire Abasq-Thomas
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | - Matthieu Talagas
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | | | - Catherine Besner-Morin
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France.,Division of Dermatology, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada
| | - Joachim W Fluhr
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France.,Department of Dermatology, Charité Universitätsmedizin, Berlin, Germany
| | - Cyril Leven
- LIEN, Univ Brest, Brest, France.,EA3878, FCRIN INNOVTE, groupe d'étude thrombose Bretagne Occidentale, Brest, France.,Department of Biochemistry and Pharmaco-Toxicology, University Hospital of Brest, Brest, France
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39
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Wercberger R, Braz JM, Weinrich JA, Basbaum AI. Pain and itch processing by subpopulations of molecularly diverse spinal and trigeminal projection neurons. Proc Natl Acad Sci U S A 2021; 118:e2105732118. [PMID: 34234018 PMCID: PMC8285968 DOI: 10.1073/pnas.2105732118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A remarkable molecular and functional heterogeneity of the primary sensory neurons and dorsal horn interneurons transmits pain- and or itch-relevant information, but the molecular signature of the projection neurons that convey the messages to the brain is unclear. Here, using retro-TRAP (translating ribosome affinity purification) and RNA sequencing, we reveal extensive molecular diversity of spino- and trigeminoparabrachial projection neurons. Among the many genes identified, we highlight distinct subsets of Cck+ -, Nptx2+ -, Nmb+ -, and Crh+ -expressing projection neurons. By combining in situ hybridization of retrogradely labeled neurons with Fos-based assays, we also demonstrate significant functional heterogeneity, including both convergence and segregation of pain- and itch-provoking inputs into molecularly diverse subsets of NK1R- and non-NK1R-expressing projection neurons.
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Affiliation(s)
- Racheli Wercberger
- Department of Anatomy, University of California, San Francisco, CA 94158
| | - Joao M Braz
- Department of Anatomy, University of California, San Francisco, CA 94158
| | - Jarret A Weinrich
- Department of Anatomy, University of California, San Francisco, CA 94158
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, CA 94158
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40
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Cui H, Su W, Cao Y, Ma L, Xu G, Mou W, Zhang H, Yu J, Ma C, Zhang X, Huang Y. Lack of Spinal Neuropeptide Y Is Involved in Mechanical Itch in Aged Mice. Front Aging Neurosci 2021; 13:654761. [PMID: 34122040 PMCID: PMC8192807 DOI: 10.3389/fnagi.2021.654761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 04/07/2021] [Indexed: 12/12/2022] Open
Abstract
Neuropeptide Y (NPY) signaling plays an essential role in gating the pruritic afferent information in the spinal cord. Recent studies revealed that the aging process down-regulated the expression of NPY in the central nervous system. We propose that the lack of spinal NPY may be involved in certain types of pruritus in the elderly population. This study was designed to investigate the role of NPY in aging-induced itch using the senile mouse model. The expression of NPY in the spinal dorsal horn was compared between young (2 months old) and aged (24 months old) mice. Western blotting and immunohistochemistry showed that the expression of NPY was significantly reduced in the spinal dorsal horn in aged mice. In addition, a neuronal maker of apoptosis, TUNEL, was detected in the NPY positive neurons only in the aged spinal cord. Behavioral assay indicated that light mechanical stimulus evoked significantly more scratching in the aged than in the young mice, whereas chemical-evoked itch and pain-related behaviors were not altered. Intrathecal injection of either NPY or LP-NPY, a NPY receptor 1 (NPY1R) agonist, significantly alleviated the mechanically evoked itch in aged mice without altering the responses to chemical pruritogens. Our study suggested that downregulation of spinal NPY in the aged mice might play a role in the higher incidence of the mechanically evoked itch than that in the young mice. Therapies targeting the NPY system might serve as a potential strategy for alleviating the pruritic symptoms among the elderly population.
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Affiliation(s)
- Huan Cui
- Department of Human Anatomy, Histology and Embryology, Neuroscience Center, Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Wenliang Su
- Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Yan Cao
- Department of Human Anatomy, Histology and Embryology, Neuroscience Center, Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Lulu Ma
- Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Guangyan Xu
- Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Wanying Mou
- Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Hanlin Zhang
- Department of Human Anatomy, Histology and Embryology, Neuroscience Center, Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Jiawen Yu
- Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Chao Ma
- Department of Human Anatomy, Histology and Embryology, Neuroscience Center, Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.,Chinese Institute for Brain Research, Beijing, China
| | - Xiuhua Zhang
- Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Yuguang Huang
- Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
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41
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Klein A, Solinski HJ, Malewicz NM, Ieong HFH, Sypek EI, Shimada SG, Hartke TV, Wooten M, Wu G, Dong X, Hoon MA, LaMotte RH, Ringkamp M. Pruriception and neuronal coding in nociceptor subtypes in human and nonhuman primates. eLife 2021; 10:64506. [PMID: 33891544 PMCID: PMC8064749 DOI: 10.7554/elife.64506] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 04/12/2021] [Indexed: 12/11/2022] Open
Abstract
In humans, intradermal administration of β-alanine (ALA) and bovine adrenal medulla peptide 8–22 (BAM8-22) evokes the sensation of itch. Currently, it is unknown which human dorsal root ganglion (DRG) neurons express the receptors of these pruritogens, MRGPRD and MRGPRX1, respectively, and which cutaneous afferents these pruritogens activate in primate. In situ hybridization studies revealed that MRGPRD and MRGPRX1 are co-expressed in a subpopulation of TRPV1+ human DRG neurons. In electrophysiological recordings in nonhuman primates (Macaca nemestrina), subtypes of polymodal C-fiber nociceptors are preferentially activated by ALA and BAM8-22, with significant overlap. When pruritogens ALA, BAM8-22, and histamine, which activate different subclasses of C-fiber afferents, are administered in combination, human volunteers report itch and nociceptive sensations similar to those induced by a single pruritogen. Our results provide evidence for differences in pruriceptive processing between primates and rodents, and do not support the spatial contrast theory of coding of itch and pain.
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Affiliation(s)
- Amanda Klein
- Department of Neurosurgery, Neurosurgery Pain Research Institute, School of Medicine, Johns Hopkins University, Baltimore, United States.,Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, United States
| | - Hans Jürgen Solinski
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research, Bethesda, United States.,Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Nathalie M Malewicz
- Department of Anesthesiology, School of Medicine, Yale University, New Haven, United States.,Department of Anesthesiology, Intensive Care Medicine and Pain Management, Medical Faculty of Ruhr-University Bochum, BG University Hospital Bergmannsheil, Bochum, Germany
| | - Hada Fong-Ha Ieong
- Department of Anesthesiology, School of Medicine, Yale University, New Haven, United States
| | - Elizabeth I Sypek
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, United States
| | - Steven G Shimada
- Department of Anesthesiology, School of Medicine, Yale University, New Haven, United States
| | - Timothy V Hartke
- Department of Neurosurgery, Neurosurgery Pain Research Institute, School of Medicine, Johns Hopkins University, Baltimore, United States
| | - Matthew Wooten
- Department of Neurosurgery, Neurosurgery Pain Research Institute, School of Medicine, Johns Hopkins University, Baltimore, United States
| | - Gang Wu
- Department of Neurosurgery, Neurosurgery Pain Research Institute, School of Medicine, Johns Hopkins University, Baltimore, United States
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, United States.,Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Mark A Hoon
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research, Bethesda, United States
| | - Robert H LaMotte
- Department of Anesthesiology, School of Medicine, Yale University, New Haven, United States
| | - Matthias Ringkamp
- Department of Neurosurgery, Neurosurgery Pain Research Institute, School of Medicine, Johns Hopkins University, Baltimore, United States
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42
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Abstract
Itch arising from glabrous skin (palms and soles) has attracted limited attention within the field due to the lack of methodology. This is despite glabrous itch arising from many medical conditions such as plantar and palmar psoriasis, dyshidrosis, and cholestasis. Therefore, we developed a mouse glabrous skin behavioral assay to investigate the contribution of three previously identified pruriceptive neurons in glabrous skin itch. Our results show that MrgprA3+ and MrgprD+ neurons, although key mediators for hairy skin itch, do not play important roles in glabrous skin itch, demonstrating a mechanistic difference in itch sensation between hairy and glabrous skin. We found that MrgprC11+ neurons are the major mediators for glabrous skin itch. Activation of MrgprC11+ neurons induced glabrous skin itch, while ablation of MrgprC11+ neurons reduced both acute and chronic glabrous skin itch. Our study provides insights into the mechanisms of itch and opens up new avenues for future glabrous skin itch research.
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43
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Sinha GP, Prasoon P, Smith BN, Taylor BK. Fast A-type currents shape a rapidly adapting form of delayed short latency firing of excitatory superficial dorsal horn neurons that express the neuropeptide Y Y1 receptor. J Physiol 2021; 599:2723-2750. [PMID: 33768539 DOI: 10.1113/jp281033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/17/2021] [Indexed: 01/29/2023] Open
Abstract
KEY POINTS Neuropeptide Y Y1 receptor-expressing neurons in the dorsal horn of the spinal cord contribute to chronic pain. For the first time, we characterized the firing patterns of Y1-expressing neurons in Y1eGFP reporter mice. Under hyperpolarized conditions, most Y1eGFP neurons exhibited fast A-type potassium currents and delayed, short-latency firing (DSLF). Y1eGFP DSLF neurons were almost always rapidly adapting and often exhibited rebound spiking, characteristics of spinal pain neurons under the control of T-type calcium channels. These results will inspire future studies to determine whether tissue or nerve injury downregulates the channels that underlie A-currents, thus unmasking membrane hyperexcitability in Y1-expressing dorsal horn neurons, leading to persistent pain. ABSTRACT Neuroanatomical and behavioural evidence indicates that neuropeptide Y Y1 receptor-expressing interneurons (Y1-INs) in the superficial dorsal horn (SDH) are predominantly excitatory and contribute to chronic pain. Using an adult ex vivo spinal cord slice preparation from Y1eGFP reporter mice, we characterized firing patterns in response to steady state depolarizing current injection of GFP-positive cells in lamina II, the great majority of which expressed Y1 mRNA (88%). Randomly sampled (RS) and Y1eGFP neurons exhibited five firing patterns: tonic, initial burst, phasic, delayed short-latency <180 ms (DSLF) and delayed long-latency >180 ms (DLLF). When studied at resting membrane potential, most RS neurons exhibited delayed firing, while most Y1eGFP neurons exhibited phasic firing. A preconditioning membrane hyperpolarization produced only subtle changes in the firing patterns of RS neurons, but dramatically shifted Y1eGFP neurons to DSLF (46%) and DLLF (24%). In contrast to RS DSLF neurons, which rarely exhibited spike frequency adaptation, Y1eGFP DSLF neurons were almost always rapidly adapting, a characteristic of nociceptive-responsive SDH neurons. Rebound spiking was more prevalent in Y1eGFP neurons (6% RS vs. 32% Y1eGFP), indicating enrichment of T-type calcium currents. Y1eGFP DSLF neurons exhibited fast A-type potassium currents that are known to delay or limit action potential firing and exhibited smaller current density as compared to RS DSLF neurons. Our results will inspire future studies to determine whether tissue or nerve injury downregulates channels that contribute to A-currents, thus potentially unmasking T-type calcium channel activity and membrane hyperexcitability in Y1-INs, leading to persistent pain.
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Affiliation(s)
- Ghanshyam P Sinha
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA, USA
| | - Pranav Prasoon
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bret N Smith
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Bradley K Taylor
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA, USA
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44
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Abstract
Mechanistic theories of itch are based on neuronal specificity, stimulus intensity, and temporal or spatial discharge patterns. Traditionally, these theories are conceptualized as mutually exclusive, assuming that finding evidence for one theory would exclude the others and could sufficiently explain itch. Current experimental data primarily support the specificity or pattern theory of itch. However, in contrast to an assumed inherent exclusivity, recent results have shown that even within itch-specific pathways in the spinal cord, temporal discharge patterns are important as sustained pruriceptor is required to allow successful transsynaptic signal progression. Also, optogenetic activation of pruriceptors suggest that the combination of neuronal specificity and temporal pattern determines the sensory effect: tonic activation of pruriceptors is required to induce scratching behavior whereas short-lasting stimulation rather causes withdrawal. In addition to the mere duration of discharge, also the temporal pattern or spatial aspects could critically contribute to elicit pruritus instead of pain. Basic neurophysiological studies trying to validate neuronal theories for pruritus in their pure form provide unitary concepts leading from neuronal discharge to the itch sensation. However, the crucial clinical questions have the opposite perspective: which mechanisms explain the chronic itch in a given patient or a given disease? In trying to solve these clinical problems we should not feel bound to the mutual exclusive nature of itch theories, but rather appreciate blending several theories and also accept combinations of itch and pain. Thus, blended versions of itch theories might better suffice for an explanation of chronic itch in patients and will improve the basis for mechanistic treatment options.
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Affiliation(s)
- Martin Schmelz
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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45
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Hu Y, Shan WQ, Wu B, Liu T. New Insight into the Origins of Itch and Pain: How are Itch and Pain Signals Coded and Discriminated by Primary Sensory Neurons? Neurosci Bull 2021; 37:575-578. [PMID: 33683647 DOI: 10.1007/s12264-021-00643-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 09/28/2020] [Indexed: 10/22/2022] Open
Affiliation(s)
- Yue Hu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Wen-Qi Shan
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Bin Wu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, 226019, China
| | - Tong Liu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, 226019, China. .,College of Life Sciences, Yanan University, Yanan, 716000, China.
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46
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Das Gupta RR, Scheurer L, Pelczar P, Wildner H, Zeilhofer HU. Neuron-specific spinal cord translatomes reveal a neuropeptide code for mouse dorsal horn excitatory neurons. Sci Rep 2021; 11:5232. [PMID: 33664406 PMCID: PMC7933427 DOI: 10.1038/s41598-021-84667-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/16/2021] [Indexed: 01/24/2023] Open
Abstract
The spinal dorsal horn harbors a sophisticated and heterogeneous network of excitatory and inhibitory neurons that process peripheral signals encoding different sensory modalities. Although it has long been recognized that this network is crucial both for the separation and the integration of sensory signals of different modalities, a systematic unbiased approach to the use of specific neuromodulatory systems is still missing. Here, we have used the translating ribosome affinity purification (TRAP) technique to map the translatomes of excitatory glutamatergic (vGluT2+) and inhibitory GABA and/or glycinergic (vGAT+ or Gad67+) neurons of the mouse spinal cord. Our analyses demonstrate that inhibitory and excitatory neurons are not only set apart, as expected, by the expression of genes related to the production, release or re-uptake of their principal neurotransmitters and by genes encoding for transcription factors, but also by a differential engagement of neuromodulator, especially neuropeptide, signaling pathways. Subsequent multiplex in situ hybridization revealed eleven neuropeptide genes that are strongly enriched in excitatory dorsal horn neurons and display largely non-overlapping expression patterns closely adhering to the laminar and presumably also functional organization of the spinal cord grey matter.
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Affiliation(s)
- Rebecca Rani Das Gupta
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Vladimir-Prelog-Weg 1-5/10, 8090, Zurich, Switzerland
| | - Louis Scheurer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Pawel Pelczar
- Center for Transgenic Models, University of Basel, 4001, Basel, Switzerland
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland. .,Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Vladimir-Prelog-Weg 1-5/10, 8090, Zurich, Switzerland.
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47
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Wang Z, Jiang C, Yao H, Chen O, Rahman S, Gu Y, Zhao J, Huh Y, Ji RR. Central opioid receptors mediate morphine-induced itch and chronic itch via disinhibition. Brain 2021; 144:665-681. [PMID: 33367648 DOI: 10.1093/brain/awaa430] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 09/29/2020] [Accepted: 10/22/2020] [Indexed: 02/27/2024] Open
Abstract
Opioids such as morphine are mainstay treatments for clinical pain conditions. Itch is a common side effect of opioids, particularly as a result of epidural or intrathecal administration. Recent progress has advanced our understanding of itch circuits in the spinal cord. However, the mechanisms underlying opioid-induced itch are not fully understood, although an interaction between µ-opioid receptor (MOR) and gastrin-releasing peptide receptor (GRPR) in spinal GRPR-expressing neurons has been implicated. In this study we investigated the cellular mechanisms of intrathecal opioid-induced itch by conditional deletion of MOR-encoding Oprm1 in distinct populations of interneurons and sensory neurons. We found that intrathecal injection of the MOR agonists morphine or DAMGO elicited dose-dependent scratching as well as licking and biting, but this pruritus was totally abolished in mice with a specific Oprm1 deletion in Vgat+ neurons [Oprm1-Vgat (Slc32a1)]. Loss of MOR in somatostatin+ interneurons and TRPV1+ sensory neurons did not affect morphine-induced itch but impaired morphine-induced antinociception. In situ hybridization revealed Oprm1 expression in 30% of inhibitory and 20% of excitatory interneurons in the spinal dorsal horn. Whole-cell recordings from spinal cord slices showed that DAMGO induced outward currents in 9 of 19 Vgat+ interneurons examined. Morphine also inhibited action potentials in Vgat+ interneurons. Furthermore, morphine suppressed evoked inhibitory postsynaptic currents in postsynaptic Vgat- excitatory neurons, suggesting a mechanism of disinhibition by MOR agonists. Notably, morphine-elicited itch was suppressed by intrathecal administration of NPY and abolished by spinal ablation of GRPR+ neurons with intrathecal injection of bombesin-saporin, whereas intrathecal GRP-induced itch response remained intact in mice lacking Oprm1-Vgat. Intrathecal bombesin-saporin treatment reduced the number of GRPR+ neurons by 97% in the lumber spinal cord and 91% in the cervical spinal cord, without changing the number of Oprm1+ neurons. Additionally, chronic itch from DNFB-induced allergic contact dermatitis was decreased by Oprm1-Vgat deletion. Finally, naloxone, but not peripherally restricted naloxone methiodide, inhibited chronic itch in the DNFB model and the CTCL model, indicating a contribution of central MOR signalling to chronic itch. Our findings demonstrate that intrathecal morphine elicits itch via acting on MOR on spinal inhibitory interneurons, leading to disinhibition of the spinal itch circuit. Our data also provide mechanistic insights into the current treatment of chronic itch with opioid receptor antagonist such as naloxone.
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Affiliation(s)
- Zilong Wang
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Changyu Jiang
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Hongyu Yao
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ouyang Chen
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Sreya Rahman
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Yun Gu
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Junli Zhao
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Yul Huh
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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48
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Wan C, Xu Y, Cen B, Xia Y, Yao L, Zheng Y, Zhao J, He S, Chen Y. Neuregulin1-ErbB4 Signaling in Spinal Cord Participates in Electroacupuncture Analgesia in Inflammatory Pain. Front Neurosci 2021; 15:636348. [PMID: 33584196 PMCID: PMC7875897 DOI: 10.3389/fnins.2021.636348] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/08/2021] [Indexed: 12/19/2022] Open
Abstract
Chronic inflammatory pain is a severe clinical symptom that aggravates the life quality of patients and places a huge economic burden on individuals and society. As one complementary and alternative therapy, electroacupuncture (EA) is widely used in clinical practice to treat chronic inflammatory pain based on its safety and efficacy. Previous studies have revealed the potential role of adenosine, neuropeptides, and inflammatory factors in EA analgesia in various pain models, but the identity of some of the signaling pathways involved remain unknown. In the present study, we explored whether neuregulin1 (NRG1)-ErbB4 signaling is involved in EA analgesia in inflammatory pain. Repeated EA treatment at the acupoints Zusanli (ST36) and Sanyinjiao (SP6) for 3 consecutive days remarkably attenuated mechanical allodynia and thermal hyperalgesia in complete Freund’s adjuvant (CFA)-treated mice, with an increased expression of NRG1 in spinal cord (SC). We found that ErbB4 kinase participated in both the EA and NRG1 mediated analgesic effects on inflammatory pain by pharmacological inhibition or genetic ablation ErbB4 in vivo. Intriguingly, the mice with conditional knockout of ErbB4 from PV+ interneurons in SC showed abnormal basal mechanical threshold. Meanwhile, NRG1 treatment could not relieve tactile allodynia in PV-Erbb4–/– mice or AAV-PV-Erbb4–/– mice after CFA injection. These experimental results suggest that regulating NRG1-ErbB4 signaling in SC could reduce pain hypersensitivity and contribute to EA analgesia in inflammatory pain.
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Affiliation(s)
- Chaofan Wan
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yunlong Xu
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China.,Shenzhen Key Laboratory of Drug Addiction, CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Baoyan Cen
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yucen Xia
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Lin Yao
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yuanjia Zheng
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jiaying Zhao
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Su He
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yongjun Chen
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China.,Guangdong-Hong Kong-Macao Greater Bay Area, Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China
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49
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Huang Y, Lu Y, Zhao X, Zhang J, Zhang F, Chen Y, Bi L, Gu J, Jiang Z, Wu X, Li Q, Liu Y, Shen J, Liu X. Cytokine activin C ameliorates chronic neuropathic pain in peripheral nerve injury rodents by modulating the TRPV1 channel. Br J Pharmacol 2020; 177:5642-5657. [PMID: 33095918 PMCID: PMC7707095 DOI: 10.1111/bph.15284] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 09/06/2020] [Accepted: 09/25/2020] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND AND PURPOSE The cytokine activin C is mainly expressed in small-diameter dorsal root ganglion (DRG) neurons and suppresses inflammatory pain. However, the effects of activin C in neuropathic pain remain elusive. EXPERIMENTAL APPROACH Male rats and wild-type and TRPV1 knockout mice with peripheral nerve injury - sciatic nerve axotomy and spinal nerve ligation in rats; chronic constriction injury (CCI) in mice - provided models of chronic neuropathic pain. Ipsilateral lumbar (L)4-5 DRGs were assayed for activin C expression. Chronic neuropathic pain animals were treated with intrathecal or locally pre-administered activin C or the vehicle. Nociceptive behaviours and pain-related markers in L4-5 DRGs and spinal cord were evaluated. TRPV1 channel modulation by activin C was measured. KEY RESULTS Following peripheral nerve injury, expression of activin βC subunit mRNA and activin C protein was markedly up-regulated in L4-5 DRGs of animals with axotomy, SNL or CCI. [Correction added on 26 November 2020, after first online publication: The preceding sentence has been corrected in this current version.] Intrathecal activin C dose-dependently inhibited neuropathic pain in spinal nerve ligated rats. Local pre-administration of activin C decreased neuropathic pain, macrophage infiltration into ipsilateral L4-5 DRGs and microglial reaction in L4-5 spinal cords of mice with CCI. In rat DRG neurons, activin C enhanced capsaicin-induced TRPV1 currents. Pre-treatment with activin C reduced capsaicin-evoked acute hyperalgesia and normalized capsaicin-evoked persistent hypothermia in mice. Finally, the analgesic effect of activin C was abolished in TRPV1 knockout mice with CCI. CONCLUSION AND IMPLICATIONS Activin C inhibits neuropathic pain by modulating TRPV1 channels, revealing potential analgesic applications in chronic neuropathic pain therapy.
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Affiliation(s)
- Ya‐Kun Huang
- School of PharmacyNantong UniversityNantongChina
- Pain and Related Diseases Research LaboratoryShantou University Medical CollegeShantouChina
| | - Yu‐Gang Lu
- Department of Anesthesiology, Shanghai Pulmonary HospitalTongji University School of MedicineShanghaiChina
| | - Xin Zhao
- Department of GeriatricsRenji Hospital, School of Medicine, Shanghai Jiaotong UniversityShanghaiChina
| | - Jing‐Bing Zhang
- Pain and Related Diseases Research LaboratoryShantou University Medical CollegeShantouChina
| | | | - Yong Chen
- School of PharmacyNantong UniversityNantongChina
| | - Ling‐Bo Bi
- School of PharmacyNantong UniversityNantongChina
| | - Jia‐Hui Gu
- School of PharmacyNantong UniversityNantongChina
| | - Zuo‐Jie Jiang
- Pain and Related Diseases Research LaboratoryShantou University Medical CollegeShantouChina
| | - Xiao‐Man Wu
- Pain and Related Diseases Research LaboratoryShantou University Medical CollegeShantouChina
| | - Qing‐Yi Li
- Pain and Related Diseases Research LaboratoryShantou University Medical CollegeShantouChina
| | - Yanli Liu
- College of Pharmaceutical ScienceSoochow UniversitySuzhouChina
| | - Jian‐Xin Shen
- Pain and Related Diseases Research LaboratoryShantou University Medical CollegeShantouChina
| | - Xing‐Jun Liu
- School of PharmacyNantong UniversityNantongChina
- Pain and Related Diseases Research LaboratoryShantou University Medical CollegeShantouChina
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50
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Peirs C, Williams SPG, Zhao X, Arokiaraj CM, Ferreira DW, Noh MC, Smith KM, Halder P, Corrigan KA, Gedeon JY, Lee SJ, Gatto G, Chi D, Ross SE, Goulding M, Seal RP. Mechanical Allodynia Circuitry in the Dorsal Horn Is Defined by the Nature of the Injury. Neuron 2020; 109:73-90.e7. [PMID: 33181066 DOI: 10.1016/j.neuron.2020.10.027] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 09/16/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022]
Abstract
The spinal dorsal horn is a major site for the induction and maintenance of mechanical allodynia, but the circuitry that underlies this clinically important form of pain remains unclear. The studies presented here provide strong evidence that the neural circuits conveying mechanical allodynia in the dorsal horn differ by the nature of the injury. Calretinin (CR) neurons in lamina II inner convey mechanical allodynia induced by inflammatory injuries, while protein kinase C gamma (PKCγ) neurons at the lamina II/III border convey mechanical allodynia induced by neuropathic injuries. Cholecystokinin (CCK) neurons located deeper within the dorsal horn (laminae III-IV) are important for both types of injuries. Interestingly, the Maf+ subset of CCK neurons is composed of transient vesicular glutamate transporter 3 (tVGLUT3) neurons, which convey primarily dynamic allodynia. Identification of an etiology-based circuitry for mechanical allodynia in the dorsal horn has important implications for the mechanistic and clinical understanding of this condition.
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Affiliation(s)
- Cedric Peirs
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Sean-Paul G Williams
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Xinyi Zhao
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Cynthia M Arokiaraj
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - David W Ferreira
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Myung-Chul Noh
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Kelly M Smith
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Priyabrata Halder
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Kelly A Corrigan
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Jeremy Y Gedeon
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Suh Jin Lee
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Graziana Gatto
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA
| | - David Chi
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Sarah E Ross
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Martyn Goulding
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA
| | - Rebecca P Seal
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA.
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