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Qiao Y, Gong J, Jin Z, Tu Y, Yang X. An optimized method of culturing neurons based on polyacrylamide gel. BIOPHYSICS REPORTS 2024; 10:41-47. [PMID: 38737477 PMCID: PMC11079600 DOI: 10.52601/bpr.2023.230033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/12/2024] [Indexed: 05/14/2024] Open
Abstract
Substrate stiffness is a microenvironment with a certain stiffness constructed by the extracellular matrix and adjacent cells, which plays an important role in the growth and development of cells and tissue formation. Studies have indicated that the stiffness of the brain is about 0.1-1 kPa. The physiological and pathological processes of the nervous system are mediated by the substrate stiffness that the neurons suffer. However, how substrate stiffness regulates these processes remains to be studied. Culturing neurons on substrates with different stiffness in vitro is one of the best methods to study the role of stiffness in regulating neuronal development and activity. In this study, by changing the preparation time and the activation time of polyacrylamide gel, we provide an improved method that achieves a low toxic substrate environment for better primary neuron adhesion and development. Hope that this method is convenient for those studying the role of substrate stiffness in neurons.
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Affiliation(s)
- Yongjing Qiao
- Key Laboratory of Cognitive Science, Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Laboratory of Membrane Ion Channels and Medicine, College of Biomedical Engineering, South-Central Minzu University, Wuhan 430074, China
| | - Jihong Gong
- Key Laboratory of Cognitive Science, Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Laboratory of Membrane Ion Channels and Medicine, College of Biomedical Engineering, South-Central Minzu University, Wuhan 430074, China
| | - Ziqi Jin
- Key Laboratory of Cognitive Science, Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Laboratory of Membrane Ion Channels and Medicine, College of Biomedical Engineering, South-Central Minzu University, Wuhan 430074, China
| | - Yiting Tu
- Key Laboratory of Cognitive Science, Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Laboratory of Membrane Ion Channels and Medicine, College of Biomedical Engineering, South-Central Minzu University, Wuhan 430074, China
| | - Xiaofei Yang
- Key Laboratory of Cognitive Science, Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Laboratory of Membrane Ion Channels and Medicine, College of Biomedical Engineering, South-Central Minzu University, Wuhan 430074, China
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2
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Gao X, Yang Y, Zhu J, Zhang Y, Wang C, Wang Z, Mi W, Du L. Xanthotoxol relieves itch in mice via suppressing spinal GRP/GRPR signaling. Eur J Pharmacol 2023; 960:176147. [PMID: 37871763 DOI: 10.1016/j.ejphar.2023.176147] [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: 06/20/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 10/25/2023]
Abstract
Although pruritus, commonly known as itch, is a common and debilitating symptom associated with various skin conditions, there is a lack of effective therapies available. Xanthotoxol (XAN), a biologically active linear furocoumarin, shows potential in the treatment of various neurological disorders. In this study, we discovered that administering XAN either through intraperitoneal or intrathecal injections effectively reduced scratching behavior induced by compound 48/80 or chloroquine. Importantly, XAN also substantially alleviates chronic itch in dry skin and allergic contact dermatitis mice. Substantial progress has highlighted the crucial role of gastrin-releasing peptide (GRP)-gastrin-releasing peptide receptor (GRPR) signaling in the dorsal spinal cord in transmitting various types of itch. Our behavior tests revealed that XAN significantly alleviated scratching behaviors induced by intrathecal administration of GRP or GRPR agonist bombesin. Furthermore, XAN reduced the activation of neurons in the spinal cord caused by intrathecal administration of GRP in mice. Moreover, XAN attenuates the activation of spinal GRPR-positive neurons in itchy mice. These findings suggest that XAN mitigates itch in mice by suppressing spinal GRP/GRPR signaling, thereby establishing XAN as a promising therapeutic option for treating pruritus.
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Affiliation(s)
- Xinyi Gao
- School of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Yayue Yang
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Jianyu Zhu
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Yuxin Zhang
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Chenghao Wang
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Zhifei Wang
- School of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
| | - Wenli Mi
- Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
| | - Lixia Du
- Department of Biochemistry, School of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
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3
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Takanami K, Kuroiwa M, Ishikawa R, Imai Y, Oishi A, Hashino M, Shimoda Y, Sakamoto H, Koide T. Function of gastrin-releasing peptide receptors in ocular itch transmission in the mouse trigeminal sensory system. Front Mol Neurosci 2023; 16:1280024. [PMID: 38098939 PMCID: PMC10719851 DOI: 10.3389/fnmol.2023.1280024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 11/03/2023] [Indexed: 12/17/2023] Open
Abstract
The prevalence of allergic conjunctivitis in itchy eyes has increased constantly worldwide owing to environmental pollution. Currently, anti-allergic and antihistaminic eye drops are used; however, there are many unknown aspects about the neural circuits that transmit itchy eyes. We focused on the gastrin-releasing peptide (GRP) and GRP receptor (GRPR), which are reportedly involved in itch transmission in the spinal somatosensory system, to determine whether the GRP system is involved in itch neurotransmission of the eyes in the trigeminal sensory system. First, the instillation of itch mediators, such as histamine (His) and non-histaminergic itch mediator chloroquine (CQ), exhibited concentration-dependent high levels of eye scratching behavior, with a significant sex differences observed in the case of His. Histological analysis revealed that His and CQ significantly increased the neural activity of GRPR-expressing neurons in the caudal part of the spinal trigeminal nucleus of the medulla oblongata in GRPR transgenic mice. We administered a GRPR antagonist or bombesin-saporin to ablate GRPR-expressing neurons, followed by His or CQ instillation, and observed a decrease in CQ-induced eye-scratching behavior in the toxin experiments. Intracisternal administration of neuromedin C (NMC), a GRPR agonist, resulted in dose-dependent excessive facial scratching behavior, despite the absence of an itch stimulus on the face. To our knowledge, this is the first study to demonstrate that non-histaminergic itchy eyes were transmitted centrally via GRPR-expressing neurons in the trigeminal sensory system, and that NMC in the medulla oblongata evoked facial itching.
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Affiliation(s)
- Keiko Takanami
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Japan
- Genetics, Research Organization of Information and Systems, Graduate University for Advanced Studies (SOKENDAI), Mishima, Japan
- Department of Environmental Health, Faculty of Human Life and Environmental Sciences, Nara Women’s University, Nara, Japan
| | - Masaya Kuroiwa
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Japan
| | - Ren Ishikawa
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Japan
| | - Yuji Imai
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Japan
- Technical Section, National Institute of Genetics, Mishima, Japan
| | - Akane Oishi
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Japan
- Technical Section, National Institute of Genetics, Mishima, Japan
| | - Midori Hashino
- Department of Environmental Health, Faculty of Human Life and Environmental Sciences, Nara Women’s University, Nara, Japan
| | - Yasushi Shimoda
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Japan
| | - Hirotaka Sakamoto
- Faculty of Environmental, Life, Natural Science and Technology, Ushimado Marine Institute (UMI), Okayama University, Okayama, Japan
- Department of Biology, Faculty of Environmental, Life, Natural Science, and Technology, Okayama University, Okayama, Japan
| | - Tsuyoshi Koide
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Japan
- Genetics, Research Organization of Information and Systems, Graduate University for Advanced Studies (SOKENDAI), Mishima, Japan
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4
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Yang Y, Mou B, Zhang QR, Zhao HX, Zhang JY, Yun X, Xiong MT, Liu Y, Liu YU, Pan H, Ma CL, Li BM, Peng J. Microglia are involved in regulating histamine-dependent and non-dependent itch transmissions with distinguished signal pathways. Glia 2023; 71:2541-2558. [PMID: 37392090 DOI: 10.1002/glia.24438] [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: 12/21/2022] [Revised: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 07/02/2023]
Abstract
Although itch and pain have many similarities, they are completely different in perceptual experience and behavioral response. In recent years, we have a deep understanding of the neural pathways of itch sensation transmission. However, there are few reports on the role of non-neuronal cells in itch. Microglia are known to play a key role in chronic neuropathic pain and acute inflammatory pain. It is still unknown whether microglia are also involved in regulating the transmission of itch sensation. In the present study, we used several kinds of transgenic mice to specifically deplete CX3CR1+ microglia and peripheral macrophages together (whole depletion), or selectively deplete microglia alone (central depletion). We observed that the acute itch responses to histamine, compound 48/80 and chloroquine were all significantly reduced in mice with either whole or central depletion. Spinal c-fos mRNA assay and further studies revealed that histamine and compound 48/80, but not chloroquine elicited primary itch signal transmission from DRG to spinal Npr1- and somatostatin-positive neurons relied on microglial CX3CL1-CX3CR1 pathway. Our results suggested that microglia were involved in multiple types of acute chemical itch transmission, while the underlying mechanisms for histamine-dependent and non-dependent itch transmission were different that the former required the CX3CL1-CX3CR1 signal pathway.
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Affiliation(s)
- Yuxiu Yang
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
- Institute of Life Science, Nanchang University, Nanchang, China
| | - Bin Mou
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
- Institute of Life Science, Nanchang University, Nanchang, China
| | - Qi-Ruo Zhang
- Institute of Life Science, Nanchang University, Nanchang, China
| | - Hong-Xue Zhao
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
- Institute of Life Science, Nanchang University, Nanchang, China
| | - Jian-Yun Zhang
- Institute of Life Science, Nanchang University, Nanchang, China
| | - Xiao Yun
- Institute of Life Science, Nanchang University, Nanchang, China
| | - Ming-Tao Xiong
- Institute of Life Science, Nanchang University, Nanchang, China
| | - Ying Liu
- Institute of Life Science, Nanchang University, Nanchang, China
| | - Yong U Liu
- Laboratory for Neuroimmunology in Health and Disease, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Haili Pan
- Institute of Life Science, Nanchang University, Nanchang, China
| | - Chao-Lin Ma
- Institute of Life Science, Nanchang University, Nanchang, China
| | - Bao-Ming Li
- Institute of Life Science, Nanchang University, Nanchang, China
- Department of Physiology and Institute of Brain Science, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, China
| | - Jiyun Peng
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
- Institute of Life Science, Nanchang University, Nanchang, China
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5
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Haruta-Tsukamoto A, Kanemaru-Kawazoe A, Kogoh Y, Miyahara Y, Funahashi H, Hirano Y, Nishimori T, Ishida Y. Role of kainate receptors in pruriceptive processing in the mouse spinal cord. Eur J Pharmacol 2023; 957:175998. [PMID: 37597648 DOI: 10.1016/j.ejphar.2023.175998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/16/2023] [Accepted: 08/17/2023] [Indexed: 08/21/2023]
Abstract
Pruritus, including neuropathic and psychogenic pruritus, is an unpleasant feeling that causes a desire to scratch, which negatively impacts physical and psychological aspects of daily life. Nonetheless, little is known about the neural mechanisms involved in pruritus. Glutamate is a predominant excitatory neurotransmitter in the mammalian central nervous system and exerts its effects by binding to various glutamate receptors, including kainate (KA) receptors; however, the precise involvement of each glutamate receptor in pruriceptive processing remains unclear, particularly that of KA receptors. Therefore, the roles of KA receptors in histamine-dependent and -independent itch were investigated using CNQX, an AMPA/KA receptors antagonist, UBP310 and UBP302, antagonists of KA receptors, and small interfering (si)RNAs against KA receptor subunits in mice with acute and chronic pruritus. The effects of KA receptor antagonists on histamine-induced c-Fos expression in the spinal cord were also examined. The intrathecal administration of CNQX reduced the number of scratching events induced by histamine and chloroquine. On the other hand, UBP310 or UBP302 and the siRNAs of KA receptor subunits 1-3 significantly inhibited the induction of scratching events in mice treated with histamine, while no significant change was observed in the induction of spontaneous scratching events in mice with chronic pruritus. In addition, antagonists of KA receptors attenuated c-Fos expression in the superficial layers of the dorsal horn induced by histamine. These results indicate that KA receptors are involved in acute pruriceptive processing in the spinal cord induced by histamine, but not chloroquine or chronic itch.
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Affiliation(s)
- Ayaka Haruta-Tsukamoto
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki City, Miyazaki, 889-1692, Japan; Nozaki Hospital, 5567 Tsunehisa, Miyazaki City, Miyazaki, 880-0916, Japan.
| | - Anna Kanemaru-Kawazoe
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki City, Miyazaki, 889-1692, Japan
| | - Yoichiro Kogoh
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki City, Miyazaki, 889-1692, Japan
| | - Yu Miyahara
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki City, Miyazaki, 889-1692, Japan
| | - Hideki Funahashi
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki City, Miyazaki, 889-1692, Japan
| | - Yoji Hirano
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki City, Miyazaki, 889-1692, Japan
| | - Toshikazu Nishimori
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki City, Miyazaki, 889-1692, Japan
| | - Yasushi Ishida
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki City, Miyazaki, 889-1692, Japan
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6
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Gutierrez-Mecinas M, Kókai É, Polgár E, Quillet R, Titterton HF, Weir GA, Watanabe M, Todd AJ. Antibodies Against the Gastrin-releasing Peptide Precursor Pro-Gastrin-releasing Peptide Reveal Its Expression in the Mouse Spinal Dorsal Horn. Neuroscience 2023; 510:60-71. [PMID: 36581131 DOI: 10.1016/j.neuroscience.2022.12.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/24/2022] [Accepted: 12/20/2022] [Indexed: 12/27/2022]
Abstract
Gastrin-releasing peptide (GRP) in the spinal dorsal horn acts on the GRP receptor, and this signalling mechanism has been strongly implicated in itch. However, the source of GRP in the dorsal horn is not fully understood. For example, the BAC transgenic mouse line GRP::GFP only captures around 25% of GRP-expressing cells, and Grp mRNA is found in several types of excitatory interneuron. A major limitation in attempts to identify GRP-expressing neurons has been that antibodies against GRP cross-react with other neuropeptides, including some that are expressed by primary afferents. Here we have developed two antibodies raised against different parts of the precursor protein, pro-GRP. We show that labelling is specific, and that the antibodies do not cross-react with neuropeptides in primary afferents. Immunoreactivity was strongest in the superficial laminae, and the two antibodies labelled identical structures, including glutamatergic axons and cell bodies. The pattern of pro-GRP-immunoreactivity varied among different neurochemical classes of excitatory interneuron. Cell bodies and axons of all GRP-GFP cells were labelled, confirming reliability of the antibodies. Among the other populations, we found the highest degree of co-expression (>50%) in axons of NPFF-expressing cells, while this was somewhat lower (10-20%) in cells that expressed substance P and NKB, and much lower (<10%) in other classes. Our findings show that these antibodies reliably detect GRP-expressing neurons and axons, and that in addition to the GRP-GFP cells, excitatory interneurons expressing NPFF or substance P are likely to be the main source of GRP in the spinal dorsal horn.
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Affiliation(s)
- Maria Gutierrez-Mecinas
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Éva Kókai
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Erika Polgár
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Raphaëlle Quillet
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Heather F Titterton
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Greg A Weir
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo 060-8638, Japan
| | - Andrew J Todd
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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7
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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: 12] [Impact Index Per Article: 6.0] [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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8
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Takanami K, Oti T, Kobayashi Y, Hasegawa K, Ito T, Tsutsui N, Ueda Y, Carstens E, Sakamoto T, Sakamoto H. Characterization of the expression of gastrin-releasing peptide and its receptor in the trigeminal and spinal somatosensory systems of Japanese macaque monkeys: Insight into humans. J Comp Neurol 2022; 530:2804-2819. [PMID: 35686563 DOI: 10.1002/cne.25376] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 05/16/2022] [Accepted: 05/18/2022] [Indexed: 11/06/2022]
Abstract
Gastrin-releasing peptide (GRP) and its receptor (GRPR) have been identified as itch mediators in the spinal and trigeminal somatosensory systems in rodents. In primates, there are few reports of GRP/GRPR expression or function in the spinal sensory system and virtually nothing is known in the trigeminal system. The aim of the present study was to characterize GRP and GRPR in the trigeminal and spinal somatosensory system of Japanese macaque monkeys (Macaca fuscata). cDNA encoding GRP was isolated from the macaque dorsal root ganglion (DRG) and exhibited an amino acid sequence that was highly conserved among mammals and especially in primates. Immunohistochemical analysis demonstrated that GRP was expressed mainly in the small-sized trigeminal ganglion and DRG in adult macaque monkeys. Densely stained GRP-immunoreactive (ir) fibers were observed in superficial layers of the spinal trigeminal nucleus caudalis (Sp5C) and the spinal cord. In contrast, GRP-ir fibers were rarely observed in the principal sensory trigeminal nucleus and oral and interpolar divisions of the spinal trigeminal nucleus. cDNA cloning, in situ hybridization, and Western blot revealed substantial expression of GRPR mRNA and GRPR protein in the macaque spinal dorsal horn and Sp5C. Our Western ligand blot and ligand derivative stain for GRPR revealed that GRP directly bound in the macaque Sp5C and spinal dorsal horn as reported in rodents. Finally, GRP-ir fibers were also detected in the human spinal dorsal horn. The spinal and trigeminal itch neural circuits labeled with GRP and GRPR appear to function also in primates.
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Affiliation(s)
- Keiko Takanami
- Ushimado Marine Institute (UMI), Okayama University, Okayama, Japan.,Department of Genetics, Mouse Genomics Resources Laboratory, National Institute of Genetics, Sokendai (The Graduate University for Advanced Studies), Shizuoka, Japan.,Department of Anatomy and Neurobiology, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California, USA
| | - Takumi Oti
- Ushimado Marine Institute (UMI), Okayama University, Okayama, Japan.,Department of Biological Sciences, Faculty of Science, Kanagawa University, Kanagawa, Japan
| | - Yasuhisa Kobayashi
- Ushimado Marine Institute (UMI), Okayama University, Okayama, Japan.,Department of Aquatic Biology, Fisheries, Faculty of Agriculture, Kindai University, Nara, Japan
| | - Koki Hasegawa
- Center for Instrumental Analysis, Kyoto Pharmaceutical University, Kyoto, Japan.,Theranostic Pharmaceuticals Laboratory, Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
| | - Takashi Ito
- Ushimado Marine Institute (UMI), Okayama University, Okayama, Japan
| | - Naoaki Tsutsui
- Ushimado Marine Institute (UMI), Okayama University, Okayama, Japan.,Department of Marine Bioresources, Mie University, Mie, Japan
| | - Yasumasa Ueda
- Department of Physiology, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Department of Physiology, Kansai Medical University, Osaka, Japan
| | - Earl Carstens
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California, USA
| | - Tatsuya Sakamoto
- Ushimado Marine Institute (UMI), Okayama University, Okayama, Japan
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9
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Kiguchi N, Ding H, Park SH, Mabry KM, Kishioka S, Shiozawa Y, Alfonso Romero-Sandoval E, Peters CM, Ko MC. Functional roles of neuromedin B and gastrin-releasing peptide in regulating itch and pain in the spinal cord of non-human primates. Biochem Pharmacol 2022; 198:114972. [PMID: 35189108 PMCID: PMC10980179 DOI: 10.1016/j.bcp.2022.114972] [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: 01/03/2022] [Revised: 02/15/2022] [Accepted: 02/15/2022] [Indexed: 11/15/2022]
Abstract
Despite accumulating evidence in rodents, the functional role of neuromedin B (NMB) in regulating somatosensory systems in primate spinal cord is unknown. We aimed to compare the expression patterns of NMB and its receptor (NMBR) and the behavioral effects of intrathecal (i.t.) NMB with gastrin-releasing peptide (GRP) on itch or pain in non-human primates (NHPs). We used six adult rhesus monkeys. The mRNA or protein expressions of NMB, GRP, and their receptors were evaluated by quantitative reverse transcription polymerase chain reaction, immunohistochemistry, or in situ hybridization. We determined the behavioral effects of NMB or GRP via acute thermal nociception, capsaicin-induced thermal allodynia, and itch scratching response assays. NMB expression levels were greater than those of GRP in the dorsal root ganglia and spinal dorsal horn. Conversely, NMBR expression was significantly lower than GRP receptor (GRPR). I.t. NMB elicited only mild scratching responses, whereas GRP caused robust scratching responses. GRP- and NMB-elicited scratching responses were attenuated by GRPR (RC-3095) and NMBR (PD168368) antagonists, respectively. Moreover, i.t. NMB and GRP did not induce thermal hypersensitivity and GRPR and NMBR antagonists did not affect peripherally elicited thermal allodynia. Consistently, NMBR expression was low in both itch- and pain-responsive neurons in the spinal dorsal horn. Spinal NMB-NMBR system plays a minimal functional role in the neurotransmission of itch and pain in primates. Unlike the functional significance of the GRP-GRPR system in itch, drugs targeting the spinal NMB-NMBR system may not effectively alleviate non-NMBR-mediated itch.
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Affiliation(s)
- Norikazu Kiguchi
- Department of Physiological Sciences, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama City, Wakayama 640-8156, Japan.
| | - Huiping Ding
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Sun H Park
- Department of Cancer Biology and Wake Forest Baptist Comprehensive Cancer Center, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Kelsey M Mabry
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Shiroh Kishioka
- Faculty of Wakayama Health Care Sciences, Takarazuka University of Medical and Health Care, Wakayama City, Wakayama 640-8392, Japan
| | - Yusuke Shiozawa
- Department of Cancer Biology and Wake Forest Baptist Comprehensive Cancer Center, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | | | - Christopher M Peters
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Mei-Chuan Ko
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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10
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Abstract
Transient receptor potential vanilloid type 1 (TRPV1) is a nonselective cation channel that is intensively expressed in the peripheral nerve system and involved in a variety of physiological and pathophysiological processes in mammals. Its activity is of great significance in transmitting pain or itch signals from peripheral sensory neurons to the central nervous system. The alteration or hypersensitivity of TRPV1 channel is well evidenced under various pathological conditions. Moreover, accumulative studies have revealed that TRPV1-expressing (TRPV1+) sensory neurons mediate the neuroimmune crosstalk by releasing neuropeptides to innervated tissues as well as immune cells. In the central projection, TRPV1+ terminals synapse with the secondary neurons for the transmission of pain and itch signalling. The intense involvement of TRPV1 and TRPV1+ neurons in pain and itch makes it a potential pharmaceutical target. Over decades, the basis of TRPV1 channel structure, the nature of its activity, and its modulation in pathological processes have been broadly studied and well documented. Herein, we highlight the role of TRPV1 and its associated neurons in sensing pain and itch. The fundamental understandings of TRPV1-involved nociception, pruriception, neurogenic inflammation, and cell-specific modulation will help bring out more effective strategies of TRPV1 modulation in treating pain- and itch-related diseases.
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11
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Meng QT, Liu XY, Liu XT, Liu J, Munanairi A, Barry DM, Liu B, Jin H, Sun Y, Yang Q, Gao F, Wan L, Peng J, Jin JH, Shen KF, Kim R, Yin J, Tao A, Chen ZF. BNP facilitates NMB-encoded histaminergic itch via NPRC-NMBR crosstalk. eLife 2021; 10:71689. [PMID: 34919054 PMCID: PMC8789279 DOI: 10.7554/elife.71689] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 12/16/2021] [Indexed: 11/13/2022] Open
Abstract
Histamine-dependent and -independent itch is conveyed by parallel peripheral neural pathways that express gastrin-releasing peptide (GRP) and neuromedin B (NMB), respectively, to the spinal cord of mice. B-type natriuretic peptide (BNP) has been proposed to transmit both types of itch via its receptor NPRA encoded by Npr1. However, BNP also binds to its cognate receptor, NPRC encoded by Npr3 with equal potency. Moreover, natriuretic peptides (NP) signal through the Gi-couped inhibitory cGMP pathway that is supposed to inhibit neuronal activity, raising the question of how BNP may transmit itch information. Here, we report that Npr3 expression in laminae I-II of the dorsal horn partially overlaps with NMB receptor (NMBR) that transmits histaminergic itch via Gq-couped PLCβ-Ca2+ signaling pathway. Functional studies indicate that NPRC is required for itch evoked by histamine but not chloroquine (CQ), a nonhistaminergic pruritogen. Importantly, BNP significantly facilitates scratching behaviors mediated by NMB, but not GRP. Consistently, BNP evoked Ca2+ responses in NMBR/NPRC HEK 293 cells and NMBR/NPRC dorsal horn neurons. These results reveal a previously unknown mechanism by which BNP facilitates NMB-encoded itch through a novel NPRC-NMBR cross-signaling in mice. Our studies uncover distinct modes of action for neuropeptides in transmission and modulation of itch in mice. An itch is a common sensation that makes us want to scratch. Most short-term itches are caused by histamine, a chemical that is released by immune cells following an infection or in response to an allergic reaction. Chronic itching, on the other hand, is not usually triggered by histamine, and is typically the result of neurological or skin disorders, such as atopic dermatitis. The sensation of itching is generated by signals that travel from the skin to nerve cells in the spinal cord. Studies in mice have shown that the neuropeptides responsible for delivering these signals differ depending on whether or not the itch involves histamine: GRPs (short for gastrin-releasing proteins) convey histamine-independent itches, while NMBs (short for neuromedin B) convey histamine-dependent itches. It has been proposed that another neuropeptide called BNP (short for B-type natriuretic peptide) is able to transmit both types of itch signals to the spinal cord. But it remains unclear how this signaling molecule is able to do this. To investigate, Meng, Liu, Liu, Liu et al. carried out a combination of behavioral, molecular and pharmacological experiments in mice and nerve cells cultured in a laboratory. The experiments showed that BNP alone cannot transmit the sensation of itching, but it can boost itching signals that are triggered by histamine. It is widely believed that BNP activates a receptor protein called NPRA. However, Meng et al. found that the BNP actually binds to another protein which alters the function of the receptor activated by NMBs. These findings suggest that BNP modulates rather than initiates histamine-dependent itching by enhancing the interaction between NMBs and their receptor. Understanding how itch signals travel from the skin to neurons in the spinal cord is crucial for designing new treatments for chronic itching. The work by Meng et al. suggests that treatments targeting NPRA, which was thought to be a key itch receptor, may not be effective against chronic itching, and that other drug targets need to be explored.
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Affiliation(s)
- Qing-Tao Meng
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Xian-Yu Liu
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Xue-Ting Liu
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Juan Liu
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Admire Munanairi
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Devin M Barry
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Benlong Liu
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Hua Jin
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Yu Sun
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Qianyi Yang
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Fang Gao
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Li Wan
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Jiahang Peng
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Jin-Hua Jin
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Kai-Feng Shen
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Ray Kim
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Jun Yin
- Center for the Study of Itch and Sensory Disorders, Washington University in St. Louis, St Louis, United States
| | - Ailin Tao
- Guangdong Provincial Key Laboratory of Allergy and Clinical Immunology, Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Zhou-Feng Chen
- Department of Anesthesiology, Washington University in St. Louis, St Louis, United States
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12
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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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13
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Estrogens influence female itch sensitivity via the spinal gastrin-releasing peptide receptor neurons. Proc Natl Acad Sci U S A 2021; 118:2103536118. [PMID: 34312228 PMCID: PMC8346901 DOI: 10.1073/pnas.2103536118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Many women exhibit a dramatic increase in itch during pregnancy, but the underlying mechanism is unknown. Here, we demonstrate that the female sex steroid hormone estradiol, but not progesterone, enhances itch-related scratching behavior in female rats elicited by histamine, the prototypical itch mediator in humans. This is associated with an enhancement in histamine-evoked activity of a subset of spinal dorsal horn neurons that express a neuropeptide receptor, gastrin-releasing peptide receptor (GRPR), that was previously shown to be involved in spinal cord processing of itch. These findings may account for why itch sensation varies with estrogen levels and provide a basis for treating histamine-related itch diseases in females by targeting GRPR. There are sex differences in somatosensory sensitivity. Circulating estrogens appear to have a pronociceptive effect that explains why females are reported to be more sensitive to pain than males. Although itch symptoms develop during pregnancy in many women, the underlying mechanism of female-specific pruritus is unknown. Here, we demonstrate that estradiol, but not progesterone, enhances histamine-evoked scratching behavior indicative of itch in female rats. Estradiol increased the expression of the spinal itch mediator, gastrin-releasing peptide (GRP), and increased the histamine-evoked activity of itch-processing neurons that express the GRP receptor (GRPR) in the spinal dorsal horn. The enhancement of itch behavior by estradiol was suppressed by intrathecal administration of a GRPR blocker. In vivo electrophysiological analysis showed that estradiol increased the histamine-evoked firing frequency and prolonged the response of spinal GRP-sensitive neurons in female rats. On the other hand, estradiol did not affect the threshold of noxious thermal pain and decreased touch sensitivity, indicating that estradiol separately affects itch, pain, and touch modalities. Thus, estrogens selectively enhance histamine-evoked itch in females via the spinal GRP/GRPR system. This may explain why itch sensation varies with estrogen levels and provides a basis for treating itch in females by targeting GRPR.
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14
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Wang B, Cardenas M, Bedoya M, Colin AA, Rossi GA. Upregulation of neuropeptides and obstructive airway disorder in infancy: A review with focus on post-RSV wheezing and NEHI. Pediatr Pulmonol 2021; 56:1297-1306. [PMID: 33524244 DOI: 10.1002/ppul.25292] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/31/2020] [Accepted: 01/11/2021] [Indexed: 12/16/2022]
Abstract
Obstructive airway disorders, common in infancy and early childhood, include some entities that are recognized to have neuro immune mediators as their underlying pathogenetic mechanisms. The best characterized example amongst post-viral wheezing phenotypes is the disorder that follows respiratory syncytial virus (RSV) infection and leads to intermittent, long-term wheezing. The underlying mechanisms of the airway reactivity related to RSV infection have been extensively studies and are associated with dysregulation of the nonadrenergic-noncholinergic (NANC) system, via upregulation of neurotransmitters, typically Substance P. Neuroendocrine hyperplasia of infancy (NEHI), while a less common entity, is a disorder characterized by more severe and long-term obstructive airway disease. NEHI is pathophysiologically characterized by abundance of neuroendocrine cells in the airways containing the neuroimmune mediator bombesin, the release of which is presumed to be the driver of the persistent small airway obstruction and functional air-trapping. Here we review the NANC and neuroendocrine cells, the neurotransmitter systems and their studied roles in pulmonary diseases with a focus on their role in lung development, and subsequent various pediatric lung diseases. We focus on the juxtaposition of the separate neuroimmune mechanisms underlying the pathogenesis of post-RSV recurrent wheezing and NEHI's persistent small airway obstruction. We finally propose a unifying concept of neuropeptides in obstructive disorders that may encompass these two entities and possibly others.
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Affiliation(s)
- Bin Wang
- Division of Critical Care Medicine, Jackson Memorial Hospital and Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Monica Cardenas
- Division of Pediatric Pulmonology, Jackson Memorial Hospital and Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Mariana Bedoya
- Division of Pediatric Pulmonology, Jackson Memorial Hospital and Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Andrew A Colin
- Division of Pediatric Pulmonology, Jackson Memorial Hospital and Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Giovanni A Rossi
- Pulmonary and Allergy Disease Unit, Department of Pediatrics, G. Gaslini University Hospital, Genoa, Italy
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15
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Kiguchi N, Fukazawa Y, Saika A, Uta D, Saika F, Nakamura TY, Ko M, Kishioka S. Chemogenetic activation of central gastrin-releasing peptide-expressing neurons elicits itch-related scratching behavior in male and female mice. Pharmacol Res Perspect 2021; 9:e00790. [PMID: 34000759 PMCID: PMC8128314 DOI: 10.1002/prp2.790] [Citation(s) in RCA: 6] [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: 04/07/2021] [Accepted: 04/19/2021] [Indexed: 12/11/2022] Open
Abstract
Several lines of evidence have clarified that the key transmission pathways of itching sensation travel from the periphery to the central nervous system (CNS). Despite the functional significance of gastrin-releasing peptide (GRP) and its cognate receptor in the itch processing mechanism in the spinal dorsal horn (SDH), the roles of GRP-expressing (GRP+ ) neurons in different regions remain unclear. This study aimed to determine whether GRP+ neurons in the CNS directly modulated itch processing. To specifically activate spinal and supraspinal GRP neurons by the designer receptors exclusively activated by designer drugs (DREADDs) system, CAG-LSL-Gq-DREADD mice were crossed with GRP-Cre mice, resulting in the development of GRP-hM3Dq mice. Immunohistochemistry showed that hM3Dq was highly expressed in the SDH and brainstem closely related to sensory processing. The intraperitoneal, intrathecal, or intracerebroventricular administration of clozapine-N-oxide, an agonist of hM3Dq, strongly elicited dermatome-dependent itch-related scratching behavior, but did not change pain sensitivity. Importantly, GRP-Gq-DREADD-mediated scratching behavior in GRP-hM3Dq mice was not affected by the ablation of transient receptor potential vanilloid 1+ sensory C-fibers, and it was also observed to a similar degree under chronic itch conditions. Furthermore, there were no significant sex differences in the scratching behavior elicited by GRP-Gq-DREADD, suggesting that itch-dominant roles of central GRP+ neurons might be common in both sexes, at least under normal physiological conditions. These novel findings not only contribute to understanding the functional roles of central GRP+ neurons further, but also propose the development of future effective therapeutics for intractable itching.
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Affiliation(s)
- Norikazu Kiguchi
- Department of PharmacologyWakayama Medical UniversityWakayama CityWakayamaJapan
- Department of Physiological SciencesSchool of Pharmaceutical SciencesWakayama Medical UniversityWakayama CityWakayamaJapan
| | - Yohji Fukazawa
- Department of AnatomyKansai University of Health SciencesSennan‐gunOsakaJapan
| | - Ayano Saika
- Department of PharmacologyWakayama Medical UniversityWakayama CityWakayamaJapan
| | - Daisuke Uta
- Department of Applied PharmacologyFaculty of Pharmaceutical SciencesUniversity of ToyamaToyama CityToyamaJapan
| | - Fumihiro Saika
- Department of PharmacologyWakayama Medical UniversityWakayama CityWakayamaJapan
| | - Tomoe Y. Nakamura
- Department of PharmacologyWakayama Medical UniversityWakayama CityWakayamaJapan
| | - Mei‐Chuan Ko
- Department of Physiology and PharmacologyWake Forest University School of MedicineWinston‐SalemNCUSA
| | - Shiroh Kishioka
- Faculty of Wakayama Health Care SciencesTakarazuka University of Medical and Health CareWakayama CityWakayamaJapan
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16
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Fan J, Mishra SK. The emerging role of neuroimmune interactions in atopic dermatitis and itch. FEBS J 2021; 289:2723-2735. [PMID: 33811449 DOI: 10.1111/febs.15860] [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: 12/14/2020] [Revised: 03/13/2021] [Accepted: 04/01/2021] [Indexed: 12/20/2022]
Abstract
Millions of people globally suffer from allergic diseases, and the cases have been rising in the past decades. One of the major manifestations of allergic diseases is itch, which is an unpleasant symptom that triggers the urge to scratch and greatly affects the quality of life. Thus, research on how sensation of itch is detected/transmitted from the contact of the allergen to the nervous system is crucial in mitigating itch. Recent studies have attempted to elucidate the mechanisms of itch in allergic diseases. Here, we aim to review the endogenous mediators released from immune/nonimmune skin cells (that are indirectly involved in the propagation of itch) and the sensory neurons that express receptors for these itch mediators that are associated with direct transmission of itch in cutaneous allergic diseases. As the mechanisms for allergic itch become clearer, new therapeutic approaches to relieve itch are likely to be developed. Recent clinical trials are testing numerous compounds that target the endogenous mediators and their receptors. These studies provide the possibility of more effective itch treatment for allergic diseases.
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Affiliation(s)
- Jennifer Fan
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Santosh K Mishra
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.,Comparative Medicine Institute, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.,Program in Genetics, North Carolina State University, Raleigh, NC, USA
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17
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Li JN, Ren JH, Zhao LJ, Wu XM, Li H, Dong YL, Li YQ. Projecting neurons in spinal dorsal horn send collateral projections to dorsal midline/intralaminar thalamic complex and parabrachial nucleus. Brain Res Bull 2021; 169:184-195. [PMID: 33508400 DOI: 10.1016/j.brainresbull.2021.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 10/22/2022]
Abstract
Itch is an annoying sensation that always triggers scratching behavior, yet little is known about its transmission pathway in the central nervous system. Parabrachial nucleus (PBN), an essential transmission nucleus in the brainstem, has been proved to be the first relay station in itch sensation. Meanwhile, dorsal midline/intralaminar thalamic complex (dMITC) is proved to be activated with nociceptive stimuli. However, whether the PBN-projecting neurons in spinal dorsal horn (SDH) send collateral projections to dMITC, and whether these projections involve in itch remain unknown. In the present study, a double retrograde tracing method was applied when the tetramethylrhodamine-dextran (TMR) was injected into the dMITC and Fluoro-gold (FG) was injected into the PBN, respectively. Immunofluorescent staining for NeuN, substance P receptor (SPR), substance P (SP), or FOS induced by itch or pain stimulations with TMR and FG were conducted to provide morphological evidence. The results revealed that TMR/FG double-labeled neurons could be predominately observed in superficial laminae and lateral spinal nucleus (LSN) of SDH; Meanwhile, most of the collateral projection neurons expressed SPR and some of them expressed FOS in acute itch model induced by histamine. The present results implicated that some of the SPR-expressing neurons in SDH send collateral projections to the dMITC and PBN in itch transmission, which might be involved in itch related complex affective/emotional processing to the higher brain centers.
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Affiliation(s)
- Jia-Ni Li
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Jia-Hao Ren
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Liu-Jie Zhao
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China
| | - Xue-Mei Wu
- Department of Human Anatomy, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Hui Li
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Lin Dong
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China.
| | - Yun-Qing Li
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China; Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China; Key Laboratory of Brain Science Research and Transformation in Tropical Environment of Hainan Province, Haikou, China.
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18
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Yang Y, Guo L, Chen Z, Jiang X, Liu Y. Benefits and harms of NK 1 R antagonists in pruritus: A systematic review and meta-analysis. Dermatol Ther 2021; 34:e14698. [PMID: 33368902 DOI: 10.1111/dth.14698] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 12/21/2020] [Indexed: 02/05/2023]
Abstract
Accumulating evidence has showed the possibility of using NK1R antagonists for the treatment of chronic pruritus. However, the benefit and risk profile of NK1R antagonists-serlopitant and aprepitant for the treatment of pruritus remains unclear. To assess the efficacy and safety of NK1R antagonists-serlopitant and aprepitant in patients with pruritus based on analysis of clinical trials. The current systematic review and meta-analysis was performed according to PRISMA guidelines. A total of 10 randomized clinical trials including 631 patients were enrolled. Four randomized controlled trials investigated the comparative treatment effect of serlopitant on pruritus. Our results showed that serlopitant had reasonable anti-pruritic effectiveness in patients, with mild toxicities. The overall proportion of 4-point improvement of NRS and VAS in serlopitant-treatment group were both significantly higher relative to placebo group (OR 2.345, 95%CI 1.557 to 3.531, P < .001; OR 3.308, 95% CI 1.949 to 5.616, P < .001). Serlopitant treatment was also found to be associated with a significant reduction in NRS score as compared with placebo (SMD -0.381, 95%CI -0.599 to -0.164, P = .001). Six clinical trials reported the treatment effect of aprepitant on pruritus. The meta-analysis result of fixed-effect model showed that there was no significant difference between aprepitant and controlled treatment in terms of improved pruritus VAS score (SMD -0.088, 95%CI -0.384 to 0.207, P = .558). There is promising high-quality evidence regarding the efficacy of serlopitant on pruritus. More large-sample randomized controlled trials with appropriate treatment regimen are urgently needed to further evaluate the effectiveness of aprepitant in pruritus.
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Affiliation(s)
- Yong Yang
- Department of Basic Medical Sciences, Sichuan Vocational College of Health and Rehabilitation, Zigong, Sichuan, China
| | - Linghong Guo
- Department of Basic Medical Sciences, Sichuan Vocational College of Health and Rehabilitation, Zigong, Sichuan, China.,Department of Dermatology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Zhiyan Chen
- Department of Basic Medical Sciences, Sichuan Vocational College of Health and Rehabilitation, Zigong, Sichuan, China
| | - Xian Jiang
- Department of Dermatology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yin Liu
- Department of Basic Medical Sciences, Sichuan Vocational College of Health and Rehabilitation, Zigong, Sichuan, China.,Department of Pharmacology, West China School of Basic Sciences and Forensic Medicine, Animal Research Institute, Sichuan University, Chengdu, Sichuan, China.,Department of Anesthesiology, Sichuan Cancer Hospital and Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
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19
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Haruta-Tsukamoto A, Miyahara Y, Funahashi H, Nishimori T, Ishida Y. Perampanel attenuates scratching behavior induced by acute or chronic pruritus in mice. Biochem Biophys Res Commun 2020; 533:1102-1108. [PMID: 33028486 DOI: 10.1016/j.bbrc.2020.09.109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 09/24/2020] [Indexed: 11/28/2022]
Abstract
An itch is defined as an unpleasant sensation that evokes a desire to scratch. Glutamate is a major excitatory neurotransmitter in the mammalian central nervous system and has a crucial role in pruriceptive processing in the spinal dorsal horn. It is well known that glutamate exerts its effects by binding to various glutamate receptors including α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, and that AMPA/kainate receptors play a crucial role in pruriceptive processing; however, the precise role of AMPA receptors remains uncertain. Perampanel, an antiepileptic drug, is an antagonist of AMPA receptors. Pretreatment with perampanel dose-dependently attenuated the induction of scratching, a behavior typically associated with pruritus, by intradermal administration of the pruritogen chloroquine. In addition, the induction of scratching in mice painted with diphenylcyclopropenone and NC/Nga mice treated with Biostir AD, animal models of contact dermatitis and atopic dermatitis, respectively, was dose-dependently alleviated by administration of perampanel. These findings indicate that AMPA receptors play a crucial role in pruriceptive processing in mice with acute or chronic pruritus.
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Affiliation(s)
- Ayaka Haruta-Tsukamoto
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki, 889-1692, Japan
| | - Yu Miyahara
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki, 889-1692, Japan
| | - Hideki Funahashi
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki, 889-1692, Japan
| | - Toshikazu Nishimori
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki, 889-1692, Japan
| | - Yasushi Ishida
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki, 889-1692, Japan.
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20
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Itch: A Paradigm of Neuroimmune Crosstalk. Immunity 2020; 52:753-766. [PMID: 32433948 DOI: 10.1016/j.immuni.2020.04.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/07/2020] [Accepted: 04/17/2020] [Indexed: 02/07/2023]
Abstract
Although the medical definition of itch has been in existence for 360 years, only in the last 20 years have we begun to understand the basic mechanisms that underlie this unique sensation. Therapeutics that specifically target chronic itch as a pathologic entity are currently still not available. Recent seminal advances in itch circuitry within the nervous system have intersected with discoveries in immunology in unexpected ways to rapidly inform emerging treatment strategies. The current review aims to introduce these basic concepts in itch biology and highlight how distinct immunologic pathways integrate with recently identified itch-sensory circuits in the nervous system to inform a major new paradigm of neuroimmunology and therapeutic development for chronic itch.
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21
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Low-Threshold Mechanosensitive VGLUT3-Lineage Sensory Neurons Mediate Spinal Inhibition of Itch by Touch. J Neurosci 2020; 40:7688-7701. [PMID: 32895292 DOI: 10.1523/jneurosci.0091-20.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 07/07/2020] [Accepted: 07/20/2020] [Indexed: 11/21/2022] Open
Abstract
Innocuous mechanical stimuli, such as rubbing or stroking the skin, relieve itch through the activation of low-threshold mechanoreceptors. However, the mechanisms behind this inhibition remain unknown. We presently investigated whether stroking the skin reduces the responses of superficial dorsal horn neurons to pruritogens in male C57BL/6J mice. Single-unit recordings revealed that neuronal responses to chloroquine were enhanced during skin stroking, and this was followed by suppression of firing below baseline levels after the termination of stroking. Most of these neurons additionally responded to capsaicin. Stroking did not suppress neuronal responses to capsaicin, indicating state-dependent inhibition. Vesicular glutamate transporter 3 (VGLUT3)-lineage sensory nerves compose a subset of low-threshold mechanoreceptors. Stroking-related inhibition of neuronal responses to chloroquine was diminished by optogenetic inhibition of VGLUT3-lineage sensory nerves in male and female Vglut3-cre/NpHR-EYFP mice. Conversely, in male and female Vglut3-cre/ChR2-EYFP mice, optogenetic stimulation of VGLUT3-lineage sensory nerves inhibited firing responses of spinal neurons to pruritogens after the termination of stimulation. This inhibition was nearly abolished by spinal delivery of the κ-opioid receptor antagonist nor-binaltorphimine dihydrochloride, but not the neuropeptide Y receptor Y1 antagonist BMS193885. Optogenetic stimulation of VGLUT3-lineage sensory nerves inhibited pruritogen-evoked scratching without affecting mechanical and thermal pain behaviors. Therefore, VGLUT3-lineage sensory nerves appear to mediate inhibition of itch by tactile stimuli.SIGNIFICANCE STATEMENT Rubbing or stroking the skin is known to relieve itch. We investigated the mechanisms behind touch-evoked inhibition of itch in mice. Stroking the skin reduced the activity of itch-responsive spinal neurons. Optogenetic inhibition of VGLUT3-lineage sensory nerves diminished stroking-evoked inhibition, and optogenetic stimulation of VGLUT3-lineage nerves inhibited pruritogen-evoked firing. Together, our results provide a mechanistic understanding of touch-evoked inhibition of itch.
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Cevikbas F, Lerner EA. Physiology and Pathophysiology of Itch. Physiol Rev 2020; 100:945-982. [PMID: 31869278 PMCID: PMC7474262 DOI: 10.1152/physrev.00017.2019] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 10/31/2019] [Accepted: 12/04/2019] [Indexed: 02/06/2023] Open
Abstract
Itch is a topic to which everyone can relate. The physiological roles of itch are increasingly understood and appreciated. The pathophysiological consequences of itch impact quality of life as much as pain. These dynamics have led to increasingly deep dives into the mechanisms that underlie and contribute to the sensation of itch. When the prior review on the physiology of itching was published in this journal in 1941, itch was a black box of interest to a small number of neuroscientists and dermatologists. Itch is now appreciated as a complex and colorful Rubik's cube. Acute and chronic itch are being carefully scratched apart and reassembled by puzzle solvers across the biomedical spectrum. New mediators are being identified. Mechanisms blur boundaries of the circuitry that blend neuroscience and immunology. Measures involve psychophysics and behavioral psychology. The efforts associated with these approaches are positively impacting the care of itchy patients. There is now the potential to markedly alleviate chronic itch, a condition that does not end life, but often ruins it. We review the itch field and provide a current understanding of the pathophysiology of itch. Itch is a disease, not only a symptom of disease.
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Affiliation(s)
- Ferda Cevikbas
- Dermira, Inc., Menlo Park, California; and Harvard Medical School and the Cutaneous Biology Research Center at Massachusetts General Hospital, Charlestown, Massachusetts
| | - Ethan A Lerner
- Dermira, Inc., Menlo Park, California; and Harvard Medical School and the Cutaneous Biology Research Center at Massachusetts General Hospital, Charlestown, Massachusetts
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Kiguchi N, Uta D, Ding H, Uchida H, Saika F, Matsuzaki S, Fukazawa Y, Abe M, Sakimura K, Ko MC, Kishioka S. GRP receptor and AMPA receptor cooperatively regulate itch-responsive neurons in the spinal dorsal horn. Neuropharmacology 2020; 170:108025. [PMID: 32142790 DOI: 10.1016/j.neuropharm.2020.108025] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/10/2020] [Accepted: 02/27/2020] [Indexed: 01/19/2023]
Abstract
Gastrin-releasing peptide (GRP) receptor-expressing (GRPR)+ neurons have a central role in the spinal transmission of itch. Because their fundamental regulatory mechanisms are not yet understood, it is important to determine how such neurons are excited and integrate itch sensation. In this study, we investigated the mechanisms for the activation of itch-responsive GRPR+ neurons in the spinal dorsal horn (SDH). GRPR+ neurons expressed the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) containing the GluR2 subunit. In mice, peripherally elicited histaminergic and non-histaminergic itch was prevented by intrathecal (i.t.) administration of the AMPAR antagonist NBQX, which was consistent with the fact that firing of GRPR+ neurons in SDH under histaminergic and non-histaminergic itch was completely blocked by NBQX, but not by the GRPR antagonist RC-3095. Because GRP+ neurons in SDH contain glutamate, we investigated the role of GRP+ (GRP+/Glu+) neurons in regulating itch. Chemogenetic inhibition of GRP+ neurons suppressed both histaminergic and non-histaminergic itch without affecting the mechanical pain threshold. In nonhuman primates, i.t. administration of NBQX also attenuated peripherally elicited itch without affecting the thermal pain threshold. In a mouse model of diphenylcyclopropenone (DCP)-induced contact dermatitis, GRP, GRPR, and AMPAR subunits were upregulated in SDH. DCP-induced itch was prevented by either silencing GRP+ neurons or ablation of GRPR+ neurons. Altogether, these findings demonstrate that GRP and glutamate cooperatively regulate GRPR+ AMPAR+ neurons in SDH, mediating itch sensation. GRP-GRPR and the glutamate-AMPAR system may play pivotal roles in the spinal transmission of itch in rodents and nonhuman primates.
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Affiliation(s)
- Norikazu Kiguchi
- Department of Pharmacology, Wakayama Medical University, Wakayama City, Wakayama, 641-0012, Japan.
| | - Daisuke Uta
- Department of Applied Pharmacology, Faculty of Pharmaceutical Sciences, University of Toyama, Toyama City, Toyama, 930-0194, Japan
| | - Huiping Ding
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, 27157, USA
| | - Hitoshi Uchida
- Department of Cellular Neuropathology, Brain Research Institute Niigata University, Niigata City, Niigata, 951-8585, Japan
| | - Fumihiro Saika
- Department of Pharmacology, Wakayama Medical University, Wakayama City, Wakayama, 641-0012, Japan
| | - Shinsuke Matsuzaki
- Department of Pharmacology, Wakayama Medical University, Wakayama City, Wakayama, 641-0012, Japan
| | - Yohji Fukazawa
- Department of Anatomy, Kansai University of Health Sciences, Sennan-gun, Osaka, 590-0482, Japan
| | - Manabu Abe
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata City, Niigata, 951-8585, Japan
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata City, Niigata, 951-8585, Japan
| | - Mei-Chuan Ko
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, 27157, USA; W.G. Hefner Veterans Affairs Medical Center, Salisbury, NC, 28144, USA
| | - Shiroh Kishioka
- Department of Pharmacology, Wakayama Medical University, Wakayama City, Wakayama, 641-0012, Japan
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Li NQ, Tang Y, Huang ST, Liu XT, Zeng LP, Li H, Wan L. Modulation of NR1 receptor by CaMKIIα plays an important role in chronic itch development in mice. Brain Res Bull 2020; 158:66-76. [PMID: 32112850 DOI: 10.1016/j.brainresbull.2020.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/22/2020] [Accepted: 02/24/2020] [Indexed: 10/24/2022]
Abstract
Intractable scratching is the characteristic of chronic itch, which represents a great challenge in clinical practice. However, the mechanism underlying chronic itch development is largely unknown. In the present study, we investigated the role of NMDA receptor in acute itch and in development of chronic itch. A mouse model was developed by painting DNFB to induce allergic contact dermatitis (ACD). We found that the expression of pNR1, which is a subunit of NMDA receptor, was significantly increased in the dorsal root ganglion in the DNFB model. The DNFB-evoked spontaneous scratching was blocked by the NMDA antagonist D-AP-5, the calcium-calmodulin-dependent protein kinase (CaMK) inhibitor KN-93, a CaMKIIα siRNA and the PKC inhibitor LY317615. Moreover, activation of PKC did not reverse the CaMKIIα knockdown-induced decrease in scratching, suggesting that PKC functions upstream of CaMKIIα. Thus, our study indicates that modulation of NR1 receptor by CaMKIIα plays an important role in the development of chronic itch.
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Affiliation(s)
- Nan-Qi Li
- Department of Pain Management, The State Key Clinical Specialty in Pain Medicine, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, P.R. China
| | - Yang Tang
- Department of Pain Management, The State Key Clinical Specialty in Pain Medicine, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, P.R. China
| | - Si-Ting Huang
- Department of Pain Management, The State Key Clinical Specialty in Pain Medicine, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, P.R. China
| | - Xue-Ting Liu
- Guangdong Provincial Key Laboratory of Allergy & Clinic Immunology, Sino-French Hoffmann Institute, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, P.R. China
| | - Li-Ping Zeng
- Guangdong Provincial Key Laboratory of Allergy & Clinic Immunology, Sino-French Hoffmann Institute, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, P.R. China
| | - Hui Li
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Li Wan
- Department of Pain Management, The State Key Clinical Specialty in Pain Medicine, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, P.R. China.
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Sandoval-Talamantes AK, Gómez-González BA, Uriarte-Mayorga DF, Martínez-Guzman MA, Wheber-Hidalgo KA, Alvarado-Navarro A. Neurotransmitters, neuropeptides and their receptors interact with immune response in healthy and psoriatic skin. Neuropeptides 2020; 79:102004. [PMID: 31902596 DOI: 10.1016/j.npep.2019.102004] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 12/22/2019] [Accepted: 12/22/2019] [Indexed: 02/06/2023]
Abstract
Psoriasis is a chronic inflammatory disease with a multifactorial origin that affects the skin. It is characterized by keratinocyte hyperproliferation, which results in erythemato-squamous plaques. Just as the immune system plays a fundamental role in psoriasis physiopathology, the nervous system maintains the inflammatory process through the neuropeptides and neurotransmitters synthesis, as histamine, serotonin, calcitonin gene-related peptide, nerve growth factor, vasoactive intestinal peptide, substance P, adenosine, glucagon-like peptide, somatostatin and pituitary adenylate cyclase polypeptide. In patients with psoriasis, the systemic or in situ expression of these chemical mediators and their receptors are altered, which affects the clinical activity of patients due to its link to the immune system, provoking neurogenic inflammation. It is important to establish the role of the nervous system since it could represent a therapeutic alternative for psoriasis patients. The aim of this review is to offer a detailed review of the current literature about the neuropeptides and neurotransmitters involved in the physiopathology of psoriasis.
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Affiliation(s)
- Ana Karen Sandoval-Talamantes
- Centro de Reabilitación Infantil Teletón de Occidente, Copal 4575, Col. Arboledas del Sur, 44980 Guadalajara, Jalisco, México
| | - B A Gómez-González
- Instituto Dermatológico de Jalisco "Dr. José Barba Rubio", Av. Federalismo Norte 3102, Col. Atemajac del Valle, 45190 Zapopan, Jalisco, México
| | - D F Uriarte-Mayorga
- Instituto Dermatológico de Jalisco "Dr. José Barba Rubio", Av. Federalismo Norte 3102, Col. Atemajac del Valle, 45190 Zapopan, Jalisco, México
| | - M A Martínez-Guzman
- Unima Diagnósticos de México, Paseo de los Mosqueteros 4181, Col. Villa Universitaria, 45110 Zapopan, Jalisco, México
| | - Katia Alejandra Wheber-Hidalgo
- Instituto Dermatológico de Jalisco "Dr. José Barba Rubio", Av. Federalismo Norte 3102, Col. Atemajac del Valle, 45190 Zapopan, Jalisco, México
| | - Anabell Alvarado-Navarro
- Centro de Investigación en Inmunología y dermatología, Universidad de Guadalajara, México, Sierra Mojada 950, Col. Independencia, 44340, Guadalajara, Jalisco, México.
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26
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Inami Y, Uta D, Andoh T. Neuronal hyperexcitability and astrocyte activation in spinal dorsal horn of a dermatitis mouse model with cutaneous hypersensitivity. Neurosci Lett 2020; 720:134784. [PMID: 31987915 DOI: 10.1016/j.neulet.2020.134784] [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: 10/01/2019] [Revised: 01/11/2020] [Accepted: 01/23/2020] [Indexed: 10/25/2022]
Abstract
Cleaning products such as soaps, shampoos, and detergents are comprised mainly of surfactants, agents known to cause dermatitis and cutaneous hypersensitivity characterized by itching, stinging, and burning of the skin and scalp. However, the mechanisms underlying surfactant-induced cutaneous hypersensitivity remain unclear. In the present study, we investigated the mechanisms of cutaneous hypersensitivity in mice treated with the detergent sodium dodecyl sulfate (SDS). Repeated SDS application to the skin induced inflammation, xeroderma, and elongation of peripheral nerves into the epidermis. The number of neurons immunopositive for c-Fos, a well known marker of neural activity, was substantially higher (+441%) in spinal dorsal horn (SDH) lamina I-II (but not lamina III-VI) of SDS-treated mice compared to vehicle-treated mice. In vivo extracellular recording revealed enhanced spontaneous (+64%) and non-noxious mechanical stimulation-evoked firing (+139%) of SDH lamina I-II neurons in SDS-treated mice, and stimulation-evoked neuronal firing was sustained (+5333%) even after stimulation. The number of GFAP-positive (activated) astrocytes, but not Iba1-positive microglia, was also elevated (+137%) in SDH lamina I-II of SDS-treated mice compared to vehicle-treated mice. Peripheral nerve elongation and hyperexcitability of afferent or SDH neurons, possible associated with the activation of spinal astrocytes, may underlie cutaneous hypersensitivity induced by surfactants.
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Affiliation(s)
- Yoshihiro Inami
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan; Advanced Research Laboratory, Hoyu Co., Ltd., Nagakute, Aichi, Japan.
| | - Daisuke Uta
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Tsugunobu Andoh
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
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Abstract
Basic mechanisms and pathways of itch signaling are reviewed, with an emphasis on the progress to date as well as remaining challenges in translating current knowledge to the clinical treatment of chronic itch. Recent studies reveal 3 subsets of pruriceptive sensory neurons highly expressing itch-related genes. Their fibers project into the spinal cord to activate neurons expressing gastrin releasing peptide (GRP) and its receptor (GRPR), which connect to neurons that express the substance P (NK-1) receptor and project to the parabrachial nucleus and thalamus. Spinal inhibitory interneurons release GABA, glycine and dynorphin to modulate segmental itch transmission. However, nearly all pruriceptive neurons also respond to algogens such as capsaicin. Alternative theories of itch-pain discrimination, such as intensity or spatial contrast, are based on the observation that focal stimulation of nociceptive nerve endings elicits itch while more widespread stimulation elicits pain. These findings cloud the issue of a labeled line for itch- a long-debated but currently unresolved challenge. In higher primates there is a dichotomy of histaminergic and non-histaminergic itch-signaling pathways which is less demarcated in rodents, suggesting species differences. A cardinal symptom of chronic itch is alloknesis, i.e., mechanical or touch-evoked itch. Recent evidence indicates that low-threshold mechanosensory afferents can access the spinal itch pathway, but are normally kept in check by inhibitory interneurons expressing neuropeptide Y (NPY). In chronic itch, NPY-mediated inhibition is reduced, allowing touch to excite itch-signaling pathways. These recent advances provide novel targets for development of therapeutic strategies to relieve chronic itch.
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Pain Inhibits GRPR Neurons via GABAergic Signaling in the Spinal Cord. Sci Rep 2019; 9:15804. [PMID: 31676846 PMCID: PMC6825123 DOI: 10.1038/s41598-019-52316-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 10/11/2019] [Indexed: 11/30/2022] Open
Abstract
It has been known that algogens and cooling could inhibit itch sensation; however, the underlying molecular and neural mechanisms remain poorly understood. Here, we show that the spinal neurons expressing gastrin releasing peptide receptor (GRPR) primarily comprise excitatory interneurons that receive direct and indirect inputs from C and Aδ fibers and form contacts with projection neurons expressing the neurokinin 1 receptor (NK1R). Importantly, we show that noxious or cooling agents inhibit the activity of GRPR neurons via GABAergic signaling. By contrast, capsaicin, which evokes a mix of itch and pain sensations, enhances both excitatory and inhibitory spontaneous synaptic transmission onto GRPR neurons. These data strengthen the role of GRPR neurons as a key circuit for itch transmission and illustrate a spinal mechanism whereby pain inhibits itch by suppressing the function of GRPR neurons.
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Ständer S, Spellman MC, Kwon P, Yosipovitch G. The NK1 receptor antagonist serlopitant for treatment of chronic pruritus. Expert Opin Investig Drugs 2019; 28:659-666. [PMID: 31272246 DOI: 10.1080/13543784.2019.1638910] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Introduction: Pruritus is a common symptom associated with several potential underlying causes, including both dermatologic and systemic diseases; it can also occur without an identifiable cause. Current treatment options are limited and most patients experience impaired quality of life. Serlopitant is a neurokinin 1 (NK1) receptor antagonist under development for the treatment of pruritus associated with various dermatologic conditions and chronic pruritus of unknown origin. Areas covered: This review describes the epidemiology and unmet needs of patients with chronic pruritus, focusing specifically on patients with prurigo nodularis, psoriatic itch, and chronic pruritus of unknown origin; the rationale for targeting the NK1 receptor for treatment of chronic pruritus; and the clinical development of serlopitant, including efficacy and safety data from completed phase II studies. Expert opinion: There is an unmet need for novel, safe, and effective therapies to treat chronic pruritus. Serlopitant has shown promising efficacy, safety, and tolerability across different patient populations, including adolescents and elderly patients. In contrast to less convenient administration options, serlopitant is a once-daily oral tablet, which is expected to facilitate compliance.
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Affiliation(s)
- Sonja Ständer
- a Dermatology and Neurodermatology, Center for Chronic Pruritus, Department of Dermatology, University Hospital Münster , Münster , Germany
| | - Mary C Spellman
- b Department of Clinical Development, Menlo Therapeutics Inc , Redwood City , CA , USA
| | - Paul Kwon
- b Department of Clinical Development, Menlo Therapeutics Inc , Redwood City , CA , USA
| | - Gil Yosipovitch
- c Miami Itch Center, Dr Phillip Frost Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami , Miami , FL , USA
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Abstract
Recent studies have made significant progress in identifying distinct populations of peripheral neurons involved in itch transmission, whereas the cellular identity of spinal interneurons that contribute to itch processing is still a debate. Combining genetic and pharmacological ablation of spinal excitatory neuronal subtypes and behavioral assays, we demonstrate that spinal somatostatin-positive (SOM) excitatory interneurons transmit pruritic sensation. We found that the ablation of spinal SOM/Lbx1 (SOM) neurons caused significant attenuation of scratching responses evoked by various chemical pruritogens (chemical itch). In an attempt to identify substrates of spinal itch neural circuit, we observed that spinal SOM neurons partially overlapped with neurons expressing natriuretic peptide receptor A (Npra), the receptor of peripheral itch transmitter B-type natriuretic peptide. Spinal SOM neurons, however, did not show any overlap with itch transmission neurons expressing gastrin-releasing peptide receptor in the dorsal spinal cord, and the gastrin-releasing peptide-triggered scratching responses were intact after ablating spinal SOM neurons. Dual ablation of SOM and Npra neurons in the spinal cord reduced chemical itch responses to a greater extent than ablation of SOM or Npra neurons alone, suggesting the existence of parallel spinal pathways transmitting chemical itch. Furthermore, we showed that SOM peptide modulated itch processing through disinhibition of somatostatin receptor 2A-positive inhibitory interneuron. Together, our findings reveal a novel spinal mechanism for sensory encoding of itch perception.
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Ständer S, Yosipovitch G. Substance P and neurokinin 1 receptor are new targets for the treatment of chronic pruritus. Br J Dermatol 2019; 181:932-938. [PMID: 31016733 DOI: 10.1111/bjd.18025] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Chronic pruritus is a distressing symptom associated with various dermatological conditions and systemic diseases. Current treatment options are often inadequate, resulting in impaired quality of life for many patients. An understanding of the underlying mechanisms of itch across pruritic conditions is important for development of effective, targeted treatments for chronic pruritus. OBJECTIVES To provide an overview of the pathogenesis of chronic pruritus, focusing on the role of substance P (SP) and neurokinin 1 receptor (NK1 R) in itch signalling, and to describe data supporting NK1 R antagonism as a potential strategy for the treatment of chronic pruritus. METHODS A PubMed search was conducted to determine what data were available that investigated the role of SP and NK1 R in itch signalling. RESULTS SP is a neuropeptide that is a mediator of itch signalling. One of the target receptors for SP is NK1 R, which is expressed in the central nervous system and on multiple cell types involved in the initiation and transmission of itch. Studies demonstrating that SP and NK1 R are overexpressed across multiple chronic itch-inducing conditions and that NK1 R antagonism disrupts itch signalling and reduces itch provide a rationale for targeting this pathway as a potential treatment of chronic pruritus across multiple diseases. CONCLUSIONS A large and growing body of evidence, including recent phase II clinical studies of NK1 R antagonists, demonstrate that SP and NK1 R play an important role in itch signalling. Additional studies are ongoing to further evaluate the use of NK1 R antagonists for the treatment of chronic pruritus. What's already known about this topic? Chronic pruritus has a significant impact on quality of life. Current treatment options for chronic pruritus are inadequate. Substance P (SP) and neurokinin 1 receptor (NK1 R) have been shown to play a role in itch signalling, and may be a rational target for addressing chronic pruritus. NK1 R antagonists are being evaluated as potential treatment for chronic pruritus. What does this study add? This review provides a compilation of the most up-to-date data elucidating the role of SP and NK1 R in itch signalling, which supports targeting this pathway as a potential treatment of chronic pruritus. NK1 R antagonism disrupts itch signalling and reduces itch. A summary of the latest data on NK1 R antagonists in the treatment of pruritus is provided.
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Affiliation(s)
- S Ständer
- Center for Chronic Pruritus, Department of Dermatology, University Hospital Münster, Münster, Germany
| | - G Yosipovitch
- Miami Itch Center, Dr Phillip Frost Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, FL, U.S.A
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Follansbee T, Akiyama T, Fujii M, Davoodi A, Nagamine M, Iodi Carstens M, Carstens E. Effects of pruritogens and algogens on rostral ventromedial medullary ON and OFF cells. J Neurophysiol 2018; 120:2156-2163. [PMID: 29947594 PMCID: PMC6295534 DOI: 10.1152/jn.00208.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/03/2018] [Accepted: 06/03/2018] [Indexed: 11/22/2022] Open
Abstract
Rostroventromedial medulla (RVM) ON and OFF cells are thought to facilitate and inhibit spinal nociceptive transmission, respectively. However, it is unknown how ON and OFF cells respond to pruritic stimuli or how they contribute to descending modulation of spinal itch signaling. In pentobarbital sodium-anesthetized mice, single-unit recordings were made in RVM from ON and OFF cells identified by their respective increase or decrease in firing that occurred just before nocifensive hindlimb withdrawal elicited by paw pinch. Of RVM ON cells, 75% (21/28) were excited by intradermal histamine, 50% (10/20) by intradermal chloroquine, and 75% (27/36) by intradermal capsaicin. Most chemically responsive units also responded to a scratch stimulus applied to the injected hindpaw. Few ON cells responded to intradermal injection of vehicle (saline: 5/32; Tween 2/17) but still responded to scratching. For OFF cells, intradermal histamine and scratching inhibited 32% (6/19) with no effect of histamine in the remainder. Intradermal chloroquine inhibited 44% (4/9) and intradermal capsaicin inhibited 61% (11/18) of OFF cells. Few OFF cells were affected by vehicles (Tween: 1 inhibited, 7 unaffected; saline: 3 excited, 1 inhibited, 8 unaffected). Both ON and OFF cells that responded to one chemical usually also responded to others, whereas units unresponsive to the first-tested chemical tended not to respond to others. These results indicate that ascending pruriceptive signals activate RVM ON cells and inhibit RVM OFF cells. These effects are considered to facilitate and disinhibit spinal pain transmission, respectively. It is currently not clear if spinal itch transmission is similarly modulated. NEW & NOTEWORTHY The rostroventromedial medulla (RVM) contains ON and OFF cells that are, respectively, excited and inhibited by noxious stimuli and have descending projections that facilitate and inhibit spinal nociceptive transmission. Most RVM ON cells were excited, and OFF cells inhibited, by intradermal injection of the pruritogens histamine and chloroquine, as well as the algogen capsaicin. These results indicate that itchy stimuli activate RVM neurons that presumably give rise to descending modulation of spinal itch transmission.
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Affiliation(s)
- T. Follansbee
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
- Center for Neuroscience, University of California, Davis, California
| | - T. Akiyama
- Department of Dermatology and Cutaneous Surgery, University of Miami School of Medicine, Miami, Florida
| | - M. Fujii
- Department of Pharmacology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - A. Davoodi
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
| | - M. Nagamine
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
| | - M. Iodi Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
| | - E. Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
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Ajayi AAL. Itching, chloroquine, and malaria: a review of recent molecular and neuroscience advances and their contribution to mechanistic understanding and therapeutics of chronic non-histaminergic pruritus. Int J Dermatol 2018; 58:880-891. [PMID: 30362504 DOI: 10.1111/ijd.14252] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/23/2018] [Accepted: 08/31/2018] [Indexed: 12/20/2022]
Abstract
Chloroquine (CQ) is an antimalarial drug that elicits severe pruritus in black Africans with malaria fever. This acute itching (2-7 days duration) exhibits age dependency and a racial and genetic predilection. CQ itch is non-histaminergic, which makes it both a good model and a tool to probe the mechanisms of chronic itch. This review focuses on recently discovered mechanisms, neuroscience, mediators, and receptors that are implicated in molecular studies of CQ pruritus. CQ pruritus mechanisms are also compared to that of itching following other systemic diseases, such as chronic kidney disease, chronic liver disease, skin disorders, and burns. There are striking similarities between CQ itching pathways and other chronic itch secondary to systemic disease with or without skin lesions, which have not been previously highlighted. Prominent among these are the shared roles of skin, neural and spinal μ opiate receptors, kappa opiate receptor, nitric oxide, serotonin via 5HT1B/D receptors, cytokines, especially interleukins, and tumor necrosis factor. There is elaborate "cross talk" among the diverse mediators and receptors involved in CQ-induced pruritus. CQ also binds to the mas-related G protein coupled receptors MrgprA3/MrgprX1 present in a small proportion (4-5%) of dorsal root ganglion neurons and skin. The mrgprA3 CQ receptors are coupled to PLC-β3 and a chloride channel to initiate skin itch action potentials in C nerve fibers. Mrgpra3/X1 couples to TRPA1 for calcium influx into neuronal cells at noncutaneous sites. Central CQ itch occurs via gastrin-related peptide (GRP) and its receptor (GRPR) in the dorsal spinothalamic tracts, as well as glutamic mediated GRP projection to parabrachial nucleus. The possibility of chronic itch therapy based on personalized medicine, genetics, and transcriptomics or the use of itch "polypill/polycream" are discussed.
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Affiliation(s)
- Adesuyi A L Ajayi
- Department of Medicine, Division of Clinical Pharmacology, Baylor College of Medicine, Houston, TX, USA
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Zhang FX, Ge SN, Dong YL, Shi J, Feng YP, Li Y, Li YQ, Li JL. Vesicular glutamate transporter isoforms: The essential players in the somatosensory systems. Prog Neurobiol 2018; 171:72-89. [PMID: 30273635 DOI: 10.1016/j.pneurobio.2018.09.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/28/2018] [Accepted: 09/23/2018] [Indexed: 02/08/2023]
Abstract
In nervous system, glutamate transmission is crucial for centripetal conveyance and cortical perception of sensory signals of different modalities, which necessitates vesicular glutamate transporters 1-3 (VGLUT 1-3), the three homologous membrane-bound protein isoforms, to load glutamate into the presysnaptic vesicles. These VGLUTs, especially VGLUT1 and VGLUT2, selectively label and define functionally distinct neuronal subpopulations at each relay level of the neural hierarchies comprising spinal and trigeminal sensory systems. In this review, by scrutinizing each structure of the organism's fundamental hierarchies including dorsal root/trigeminal ganglia, spinal dorsal horn/trigeminal sensory nuclear complex, somatosensory thalamic nuclei and primary somatosensory cortex, we summarize and characterize in detail within each relay the neuronal clusters expressing distinct VGLUT protein/transcript isoforms, with respect to their regional distribution features (complementary distribution in some structures), axonal terminations/peripheral innervations and physiological functions. Equally important, the distribution pattern and characteristics of VGLUT1/VGLUT2 axon terminals within these structures are also epitomized. Finally, the correlation of a particular VGLUT isoform and its physiological role, disclosed thus far largely via studying the peripheral receptors, is generalized by referring to reports on global and conditioned VGLUT-knockout mice. Also, researches on VGLUTs relating to future direction are tentatively proposed, such as unveiling the elusive differences between distinct VGLUTs in mechanism and/or pharmacokinetics at ionic/molecular level, and developing VGLUT-based pain killers.
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Affiliation(s)
- Fu-Xing Zhang
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Shun-Nan Ge
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China; Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
| | - Yu-Lin Dong
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Juan Shi
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Yu-Peng Feng
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Yang Li
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
| | - Yun-Qing Li
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, PR China.
| | - Jin-Lian Li
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China.
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Espino SS, Robinson SD, Safavi-Hemami H, Gajewiak J, Yang W, Olivera BM, Liu Q. Conopeptides promote itch through human itch receptor hMgprX1. Toxicon 2018; 154:28-34. [PMID: 30243794 DOI: 10.1016/j.toxicon.2018.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/06/2018] [Accepted: 09/14/2018] [Indexed: 11/30/2022]
Abstract
Members of Mas related G-protein coupled receptors (Mrgpr) are known to mediate itch. To date, several compounds have been shown to activate these receptors, including chloroquine, a common antimalarial drug, and peptides of the RF-amide family. However, specific ligands for these receptors are still lacking and there is a need for novel compounds that can be used to modulate the receptors in order to understand the cellular and molecular mechanism in which they mediate itch. Some cone snail venoms were previously shown to induce itch in mice. Here, we show that the venom of Conus textile induces itch through activation of itch-sensing sensory neurons, marked by their sensitivity to chloroquine. Two RF-amide peptides, CNF-Tx1 and CNF-Tx2, were identified in a C. textile venom gland transcriptome. These belong to the conorfamide family of peptides which includes previously described peptides from the venoms of Conus victoriae (CNF-Vc1) and Conus spurius (CNF-Sr1 and CNF-Sr2). We show that CNF-Vc1 and CNF-Sr1 activate MrgprC11 whereas CNF-Vc1 and CNF-Tx2 activate the human MrgprX1 (hMrgprX1). The peptides CNF-Tx1 and CNF-Sr2 do not activate MrgprC11 or hMrgprX1. Intradermal injection of CNF-Vc1 and CNF-Tx2 into the cheek of a transgenic mouse expressing hMrgprX1 instead of endogenous mouse Mrgprs resulted in itch-related scratching thus demonstrating the in vivo activity of these peptides. Using truncated analogues of CNF-Vc1, we identified amino acids at positions 7-14 as important for activity against hMrgprX1. The conopeptides reported here are tools that can be used to advance our understanding of the cellular and molecular mechanism of itch mediated by Mrgprs.
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Affiliation(s)
- Samuel S Espino
- Department of Anesthesiology and Center for the Study of Itch, Washington University School of Medicine, St. Louis MO 63110, USA
| | - Samuel D Robinson
- Department of Biology, University of Utah, Salt Lake City UT 84112, USA
| | - Helena Safavi-Hemami
- Department of Biology, University of Utah, Salt Lake City UT 84112, USA; Department of Biochemistry, University of Utah, Salt Lake City UT 84112, USA
| | - Joanna Gajewiak
- Department of Biology, University of Utah, Salt Lake City UT 84112, USA
| | - Weishan Yang
- Department of Anesthesiology and Center for the Study of Itch, Washington University School of Medicine, St. Louis MO 63110, USA
| | | | - Qin Liu
- Department of Anesthesiology and Center for the Study of Itch, Washington University School of Medicine, St. Louis MO 63110, USA.
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Munanairi A, Liu XY, Barry DM, Yang Q, Yin JB, Jin H, Li H, Meng QT, Peng JH, Wu ZY, Yin J, Zhou XY, Wan L, Mo P, Kim S, Huo FQ, Jeffry J, Li YQ, Bardoni R, Bruchas MR, Chen ZF. Non-canonical Opioid Signaling Inhibits Itch Transmission in the Spinal Cord of Mice. Cell Rep 2018; 23:866-877. [PMID: 29669290 PMCID: PMC5937707 DOI: 10.1016/j.celrep.2018.03.087] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/28/2018] [Accepted: 03/20/2018] [Indexed: 01/20/2023] Open
Abstract
Chronic itch or pruritus is a debilitating disorder that is refractory to conventional anti-histamine treatment. Kappa opioid receptor (KOR) agonists have been used to treat chronic itch, but the underlying mechanism remains elusive. Here, we find that KOR and gastrin-releasing peptide receptor (GRPR) overlap in the spinal cord, and KOR activation attenuated GRPR-mediated histamine-independent acute and chronic itch in mice. Notably, canonical KOR-mediated Gαi signaling is not required for desensitizing GRPR function. In vivo and in vitro studies suggest that KOR activation results in the translocation of Ca2+-independent protein kinase C (PKC)δ from the cytosol to the plasma membrane, which in turn phosphorylates and inhibits GRPR activity. A blockade of phospholipase C (PLC) in HEK293 cells prevented KOR-agonist-induced PKCδ translocation and GRPR phosphorylation, suggesting a role of PLC signaling in KOR-mediated GRPR desensitization. These data suggest that a KOR-PLC-PKCδ-GRPR signaling pathway in the spinal cord may underlie KOR-agonists-induced anti-pruritus therapies.
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MESH Headings
- Animals
- Cell Membrane/metabolism
- Chloroquine/toxicity
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- HEK293 Cells
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Phosphorylation
- Protein Kinase C-delta/antagonists & inhibitors
- Protein Kinase C-delta/genetics
- Protein Kinase C-delta/metabolism
- Pruritus/chemically induced
- Pruritus/pathology
- RNA Interference
- RNA, Small Interfering/metabolism
- Receptors, Bombesin/metabolism
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/deficiency
- Receptors, Opioid, kappa/genetics
- Signal Transduction
- Spinal Cord/metabolism
- Type C Phospholipases/antagonists & inhibitors
- Type C Phospholipases/metabolism
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Affiliation(s)
- Admire Munanairi
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Xian-Yu Liu
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Devin M Barry
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Qianyi Yang
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jun-Bin Yin
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, 710032 Xi'an, PRC
| | - Hua Jin
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hui Li
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, 710032 Xi'an, PRC
| | - Qing-Tao Meng
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jia-Hang Peng
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Zhen-Yu Wu
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, 710032 Xi'an, PRC
| | - Jun Yin
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Xuan-Yi Zhou
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Li Wan
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, 710032 Xi'an, PRC
| | - Ping Mo
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, 710032 Xi'an, PRC
| | - Seungil Kim
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Fu-Quan Huo
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Joseph Jeffry
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Yun-Qing Li
- Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, 710032 Xi'an, PRC; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, PRC
| | - Rita Bardoni
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena 41125, Italy
| | - Michael R Bruchas
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Zhou-Feng Chen
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Wan L, Jin H, Liu XY, Jeffry J, Barry DM, Shen KF, Peng JH, Liu XT, Jin JH, Sun Y, Kim R, Meng QT, Mo P, Yin J, Tao A, Bardoni R, Chen ZF. Distinct roles of NMB and GRP in itch transmission. Sci Rep 2017; 7:15466. [PMID: 29133874 PMCID: PMC5684337 DOI: 10.1038/s41598-017-15756-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 11/01/2017] [Indexed: 01/12/2023] Open
Abstract
A key question in our understanding of itch coding mechanisms is whether itch is relayed by dedicated molecular and neuronal pathways. Previous studies suggested that gastrin-releasing peptide (GRP) is an itch-specific neurotransmitter. Neuromedin B (NMB) is a mammalian member of the bombesin family of peptides closely related to GRP, but its role in itch is unclear. Here, we show that itch deficits in mice lacking NMB or GRP are non-redundant and Nmb/Grp double KO (DKO) mice displayed additive deficits. Furthermore, both Nmb/Grp and Nmbr/Grpr DKO mice responded normally to a wide array of noxious stimuli. Ablation of NMBR neurons partially attenuated peripherally induced itch without compromising nociceptive processing. Importantly, electrophysiological studies suggested that GRPR neurons receive glutamatergic input from NMBR neurons. Thus, we propose that NMB and GRP may transmit discrete itch information and NMBR neurons are an integral part of neural circuits for itch in the spinal cord.
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Affiliation(s)
- Li Wan
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Pain Medicine, The State Key Clinical Specialty in Pain Medicine, The Second Affiliated Hospital, Guangzhou Medical University, Guangdong, 510260, P.R. China
| | - Hua Jin
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, The First Hospital of Yunnan Province, Kunming, Yunnan, 650031, P.R. China
| | - Xian-Yu Liu
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Joseph Jeffry
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Devin M Barry
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Kai-Feng Shen
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, P.R. China
| | - Jia-Hang Peng
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Xue-Ting Liu
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Guangdong Provincial Key Laboratory of Allergy & Clinical Immunology, The State Key Laboratory of Respiratory Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 510260, P.R. China
| | - Jin-Hua Jin
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100144, P.R. China
| | - Yu Sun
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, P.R. China
| | - Ray Kim
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Qing-Tao Meng
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, Hubei, 430060, P.R. China
| | - Ping Mo
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, the Affiliated Nanhai Hospital of Southern Medical University, Foshan, Guangdong, 528000, P.R. China
| | - Jun Yin
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Ailin Tao
- Guangdong Provincial Key Laboratory of Allergy & Clinical Immunology, The State Key Laboratory of Respiratory Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 510260, P.R. China
| | - Rita Bardoni
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, 41125, Italy
| | - Zhou-Feng Chen
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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Tarrasón G, Carcasona C, Eichhorn P, Pérez B, Gavaldà A, Godessart N. Characterization of the chloroquine-induced mouse model of pruritus using an automated behavioural system. Exp Dermatol 2017; 26:1105-1111. [DOI: 10.1111/exd.13392] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Gema Tarrasón
- Skin Biology and Pharmacology; Almirall R&D Center; Sant Feliu de Llobregat Barcelona Spain
| | - Carla Carcasona
- Skin Biology and Pharmacology; Almirall R&D Center; Sant Feliu de Llobregat Barcelona Spain
| | - Peter Eichhorn
- Pharmacokinetics and Metabolism; Almirall R&D Center; Sant Feliu de Llobregat Barcelona Spain
| | - Bibiana Pérez
- Pharmacokinetics and Metabolism; Almirall R&D Center; Sant Feliu de Llobregat Barcelona Spain
| | - Amadeu Gavaldà
- Skin Biology and Pharmacology; Almirall R&D Center; Sant Feliu de Llobregat Barcelona Spain
| | - Núria Godessart
- Skin Biology and Pharmacology; Almirall R&D Center; Sant Feliu de Llobregat Barcelona Spain
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Liu BW, Li ZX, He ZG, Liu C, Xiong J, Xiang HB. Altered expression of target genes of spinal cord in different itch models compared with capsaicin assessed by RT-qPCR validation. Oncotarget 2017; 8:74423-74433. [PMID: 29088797 PMCID: PMC5650352 DOI: 10.18632/oncotarget.20148] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 05/23/2017] [Indexed: 11/25/2022] Open
Abstract
Spinal cord plays a central role in the development and progression of pathogenesis of obstinate pruritus. In the current study, four groups of adult male C57Bl/6 mice were investigated; one group treated with saline, while the other groups intradermally injected with compound 48/80, histamine, α-Me-5-HT and capsaicin (algogenic substance), respectively. The intradermal microinjection of pruritic and algogenic compound resulted in a dramatic increase in the itch/algogenic behavior. Analysis of the microarray data showed that 15 genes in spinal cord (C5-C8) were differentially expressed between control group and 48/80 group, in which 9 genes were up-regulated and 6 genes were down-regulated. Furthermore, the results of RT-qPCR validation studies in C5-C8 spinal cord revealed that the 9 mRNA (Sgk1, Bag4, Fos, Ehd2, Edn3, Wdfy, Corin, 4921511E18Rik and 4930423020Rik) showed very different patterns for these different drugs, especially when comparing α-Me-5-HT and capsaicin. In three itch models, Fos and Ehd2 were up-regulated whereas Corin, 4921511E18Rik and 4930423020Rik were down-regulated. Furthermore, Corin and 4930423020Rik were down-regulated in itch model group compared to capsaicin group. Thus the application of microarray technique, coupled with RT-qPCR validation, further explain the mechanism behind itching evoked by pruritic compounds. It can contribute to our understanding of pharmacological methods for prevention or treatment of obstinate pruritus.
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Affiliation(s)
- Bao-Wen Liu
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhi-Xiao Li
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhi-Gang He
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Cheng Liu
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jun Xiong
- Hepatobiliary Surgery Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong-Bing Xiang
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Horiuchi M, Suzuki-Horiuchi Y, Akiyama T, Itoh A, Pleasure D, Carstens E, Itoh T. Differing intrinsic biological properties between forebrain and spinal oligodendroglial lineage cells. J Neurochem 2017; 142:378-391. [PMID: 28512742 DOI: 10.1111/jnc.14074] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/11/2017] [Accepted: 05/12/2017] [Indexed: 12/21/2022]
Abstract
Differentiation of oligodendroglial progenitor cells (OPCs) into myelinating oligodendrocytes is known to be regulated by the microenvironment where they differentiate. However, current research has not verified whether or not oligodendroglial lineage cells (OLCs) derived from different anatomical regions of the central nervous system (CNS) respond to microenvironmental cues in the same manner. Here, we isolated pure OPCs from rat neonatal forebrain (FB) and spinal cord (SC) and compared their phenotypes in the same in vitro conditions. We found that although FB and SC OLCs responded differently to the same external factors; they were distinct in proliferation response to mitogens, oligodendrocyte phenotype after differentiation, and cytotoxic responses to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate-type glutamate receptor-mediated excitotoxicity at immature stages of differentiation in a cell-intrinsic manner. Moreover, transcriptome analysis identified genes differentially expressed between these OPC populations, including those encoding transcription factors (TFs), cell surface molecules, and signaling molecules. Particularly, FB and SC OPCs retained the expression of FB- or SC-specific TFs, such as Foxg1 and Hoxc8, respectively, even after serial passaging in vitro. Given the essential role of these TFs in the regional identities of CNS cells along the rostrocaudal axis, our results suggest that CNS region-specific gene regulation by these TFs may cause cell-intrinsic differences in cellular responses between FB and SC OLCs to extracellular molecules. Further understanding of the regional differences among OPC populations will help to improve treatments for demyelination in different CNS regions and to facilitate the development of stem cell-derived OPCs for cell transplantation therapies for demyelination. Cover Image for this issue: doi. 10.1111/jnc.13809.
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Affiliation(s)
- Makoto Horiuchi
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
| | - Yoko Suzuki-Horiuchi
- Department of Dermatology, Institute of Regenerative Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Tasuku Akiyama
- Temple Itch Center, Department of Dermatology, Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
| | - Aki Itoh
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, California, USA.,Department of Neurology, School of Medicine, University of California, Sacramento, California, USA
| | - David Pleasure
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, California, USA.,Department of Neurology, School of Medicine, University of California, Sacramento, California, USA
| | - Earl Carstens
- Department of Neurobiology, Physiology & Behavior, University of California, Davis, California, USA
| | - Takayuki Itoh
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, California, USA.,Department of Neurology, School of Medicine, University of California, Sacramento, California, USA
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Haddadi NS, Foroutan A, Ostadhadi S, Azimi E, Rahimi N, Nateghpour M, Lerner EA, Dehpour AR. Peripheral NMDA Receptor/NO System Blockage Inhibits Itch Responses Induced by Chloroquine in Mice. Acta Derm Venereol 2017; 97:571-577. [PMID: 28119997 DOI: 10.2340/00015555-2617] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Intradermal administration of chloroquine (CQ) provokes scratching behavior in mice. Chloroquine-induced itch is histamine-independent and we have reported that the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway is involved in CQ-induced scratching behavior in mice. Previous studies have demonstrated that activation of N-methyl-d-aspartate receptors (NMDARs) induces NO production. Here we show that NMDAR antagonists significantly decrease CQ-induced scratching in mice while a non-effective dose of an NMDAR agonist potentiates the scratching behavior provoked by sub-effective doses of CQ. In contrast, combined pre-treatment with sub-effective doses of an NMDAR antagonist, MK-801, and the NO synthase inhibitor, L-N-nitro arginine methyl ester (L-NAME), decreases CQ-induced scrat-ching behavior. While intradermal administration of CQ significantly increases the concentration of intradermal nitrite, the end product of NO metabolism, effective doses of intraperitoneal and intradermal MK-801 significantly decrease intradermal nitrite levels. Likewise, administration of an effective dose of L-NAME significantly decreases CQ-induced nitrite production. We conclude that the NMDA/NO pathway in the skin modulates CQ-induced scratching behavior.
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Affiliation(s)
- Nazgol-Sadat Haddadi
- Experimental Medicine Research Center, Tehran University of Medical Sciences, 13145-784 Tehran, Iran
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Distribution of hemokinin-1 in the rat trigeminal ganglion and trigeminal sensory nuclear complex. Arch Oral Biol 2017; 79:62-69. [PMID: 28301818 DOI: 10.1016/j.archoralbio.2017.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 01/18/2017] [Accepted: 03/05/2017] [Indexed: 11/24/2022]
Abstract
OBJECTIVE A new mammalian tachykinin peptide encoded in a TAC4 gene was identified and designated as hemokinin-1 (HK-1). A representative of the tachykinin peptide family is substance P (SP), and the function of SP has been well characterized as a pain transmitter or modulator, while it is possible that HK-1 is involved in pruriceptive processing, but, as yet, the distribution of HK-1 peptide in the trigeminal sensory system is still unknown. Thus, the aim of the present study was to elucidate the distribution of HK-1, while comparing the expression of SP, in the trigeminal ganglion and trigeminal sensory nuclear complex. DESIGN The trigeminal ganglion and the brain stem of male SD rats were used in the immunohistochemical study. Since the amino acid sequence in the carboxyl-terminal regions of HK-1 and SP is common, polyclonal antibodies of HK-1 and SP derived from 6 amino acids consisting of amino-terminal regions of these peptides were produced in guinea pig and rabbit, respectively. The immunohistochemical staining of HK-1 and SP was conducted using frozen sections of the trigeminal ganglion and brain stem in rats. RESULTS Immunohistochemical studies revealed the expression of HK-1 in small- and medium-sized trigeminal ganglion neurons, in the paratrigeminal nucleus, and in lamina I of the trigeminal nucleus caudalis, while there was no immunoreactivity of HK-1 in the trigeminal nucleus principalis, trigeminal nucleus oralis, and trigeminal nucleus interpolaris. CONCLUSION These findings indicate that HK-1 is a target molecule for treatment of itch in the orofaicial regions.
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Takanami K, Inoue K, Mukai H, Tamura K, Jogahara T, Oda SI, Kawata M, Sakamoto T, Sakamoto H. Comparative Anatomy of Gastrin-releasing Peptide Pathways in the Trigeminal Sensory System of Mouse and the Asian House Musk Shrew Suncus murinus. Acta Histochem Cytochem 2016; 49:181-190. [PMID: 28127106 PMCID: PMC5263228 DOI: 10.1267/ahc.16030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 10/09/2016] [Indexed: 01/02/2023] Open
Abstract
Gastrin-releasing peptide (GRP) has recently been identified as an itch-signaling molecule in the primary afferents and spinal cord of rodents. However, little information exists on the expression and localization of GRP in the trigeminal somatosensory system other than in rats. We examined the generality of the trigeminal GRP system in mammals using two distinct species, suncus as a model of specialized placental mammals known to have a well-developed trigeminal sensory system and mice as a representative small laboratory animal. We first analyzed the gross morphology of the trigeminal somatosensory system in suncus to provide a brainstem atlas on which to map GRP distribution. Immunohistochemical analyses showed that 8% of trigeminal ganglion neurons in suncus and 6% in mice expressed GRP. Expression was restricted to cells with smaller somata. The GRP-containing fibers were densely distributed in the superficial layers of the caudal part of the trigeminal spinal nucleus (Vc) but rare in the rostral parts, both in suncus and mice. Expression of GRP receptor mRNA and protein was also detected in the Vc of suncus. Taken together, these results suggest that the trigeminal GRP system mediating itch sensation is conserved in mammals.
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Affiliation(s)
- Keiko Takanami
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University
- Anatomy and Neurobiology, Kyoto Prefectural University of Medicine
| | - Kaihei Inoue
- Anatomy and Neurobiology, Kyoto Prefectural University of Medicine
| | - Hiroki Mukai
- Anatomy and Neurobiology, Kyoto Prefectural University of Medicine
| | - Kei Tamura
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University
| | - Takamichi Jogahara
- Laboratory of Animal Management and Resources, Department of Zoology, Okayama University of Science
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki
| | - Sen-ichi Oda
- Laboratory of Animal Management and Resources, Department of Zoology, Okayama University of Science
| | - Mitsuhiro Kawata
- Anatomy and Neurobiology, Kyoto Prefectural University of Medicine
- School of Health Science, Bukkyo University
| | - Tatsuya Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University
| | - Hirotaka Sakamoto
- Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University
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Furue M, Kadono T. New therapies for controlling atopic itch. J Dermatol 2016; 42:847-50. [PMID: 26332459 DOI: 10.1111/1346-8138.13060] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 06/30/2015] [Indexed: 12/17/2022]
Abstract
Chronic itch in atopic dermatitis markedly diminishes the quality of life of affected individuals. Sleep disturbance and impaired productivity in work due to chronic itch impose a socioeconomic burden. Conventional therapies for atopic dermatitis are capable of reducing atopic itch. However, the majority of patients are not satisfied with the antipruritic capacity of conventional treatments. In this review, we summarize recent progress in itch signaling in the skin, dorsal root ganglion and spinal cord. New therapies for controlling atopic itch are also discussed.
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Affiliation(s)
- Masutaka Furue
- Department of Dermatology, Kyushu University, Fukuoka, Japan
| | - Takafumi Kadono
- Department of Dermatology, St Marianna University School of Medicine, Kawasaki, Japan
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Abstract
This chapter summarizes recent findings regarding the central transmission of acute and chronic itch. Itch is transduced by cutaneous pruriceptors that transmit signals to neurons in the superficial spinal cord. Spinal itch-signaling circuits utilize several neuropeptides whose receptors represent novel targets to block itch transmission. Itch is relieved by scratching, which activates spinal interneurons to inhibit itch-transmitting neurons. Spinal itch transmission is also thought to be modulated by descending pathways. Itch is transmitted rostrally via ascending pathways to activate a variety of brain regions involved in sensory discrimination of affective and motor responses to itch. The pathophysiological mechanisms of chronic itch are poorly understood but likely involve sensitization of itch-signaling pathways and/or dysfunction of itch-inhibitory circuits. Improved understanding of central itch mechanisms has identified a number of novel targets for the development of antipruritic treatment strategies.
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Inoue A, Uchida H, Nakazawa T, Yamamoto T, Ito S. Phosphorylation of NMDA receptor GluN2B subunit at Tyr1472 is important for trigeminal processing of itch. Eur J Neurosci 2016; 44:2474-2482. [DOI: 10.1111/ejn.13337] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 07/01/2016] [Accepted: 07/11/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Akitoshi Inoue
- Department of Medical Chemistry; Kansai Medical University; Hirakata 573-1010 Japan
| | - Hitoshi Uchida
- Department of Medical Chemistry; Kansai Medical University; Hirakata 573-1010 Japan
| | - Takanobu Nakazawa
- Drug Innovation Center; Graduate School of Pharmaceutical Science; Osaka University; Suita Japan
| | - Tadashi Yamamoto
- Cell Signal Unit; Okinawa Institute of Science and Technology Graduate University; Okinawa Japan
| | - Seiji Ito
- Department of Medical Chemistry; Kansai Medical University; Hirakata 573-1010 Japan
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Gaspar NK, Aidé MK. Atopic dermatitis: allergic dermatitis or neuroimmune dermatitis? An Bras Dermatol 2016; 91:479-88. [PMID: 27579744 PMCID: PMC4999107 DOI: 10.1590/abd1806-4841.20164211] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 04/16/2015] [Indexed: 05/05/2023] Open
Abstract
Advances in knowledge of neurocellulars relations have provided new directions in the understanding and treatment of numerous conditions, including atopic dermatitis. It is known that emotional, physical, chemical or biological stimuli can generate more accentuated responses in atopic patients than in non-atopic individuals; however, the complex network of control covered by these influences, especially by neuropeptides and neurotrophins, and their genetic relations, still keep secrets to be revealed. Itching and airway hyperresponsiveness, the main aspects of atopy, are associated with disruption of the neurosensory network activity. Increased epidermal innervation and production of neurotrophins, neuropeptides, cytokines and proteases, in addition to their relations with the sensory receptors in an epidermis with poor lipid mantle, are the aspects currently covered for understanding atopic dermatitis.
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Bell AM, Gutierrez-Mecinas M, Polgár E, Todd AJ. Spinal neurons that contain gastrin-releasing peptide seldom express Fos or phosphorylate extracellular signal-regulated kinases in response to intradermal chloroquine. Mol Pain 2016; 12:12/0/1744806916649602. [PMID: 27270268 PMCID: PMC4937990 DOI: 10.1177/1744806916649602] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/08/2016] [Indexed: 12/25/2022] Open
Abstract
Background Gastrin-releasing peptide (GRP) is thought to play a role in the itch evoked by intradermal injection of chloroquine. Although some early studies suggested that GRP was expressed in pruriceptive primary afferents, it is now thought that GRP in the spinal cord is derived mainly from a population of excitatory interneurons in lamina II, and it has been suggested that these are involved in the itch pathway. To test this hypothesis, we used the transcription factor Fos and phosphorylation of extracellular signal-regulated kinases (ERK) to look for evidence that interneurons expressing GRP were activated following intradermal injection of chloroquine into the calf, in mice that express enhanced green fluorescent protein (EGFP) in these cells. Results Injection of chloroquine resulted in numerous Fos- or phospho-ERK (pERK) positive cells in the somatotopically appropriate part of the superficial dorsal horn. The proportion of all neurons in this region that showed Fos or pERK was 18% and 21%, respectively. However, among the GRP–EGFP, only 7% were Fos-positive and 3% were pERK-positive. As such, GRP–EGFP cells were significantly less likely than other neurons to express Fos or to phosphorylate ERK. Conclusions Both expression of Fos and phosphorylation of ERK can be used to identify dorsal horn neurons activated by chloroquine injection. However, these results do not support the hypothesis that interneurons expressing GRP are critical components in the itch pathway.
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Affiliation(s)
- Andrew M Bell
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Maria Gutierrez-Mecinas
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Erika Polgár
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Electrophysiological properties of brain-natriuretic peptide- and gastrin-releasing peptide-responsive dorsal horn neurons in spinal itch transmission. Neurosci Lett 2016; 627:51-60. [PMID: 27235577 DOI: 10.1016/j.neulet.2016.05.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/18/2016] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
Abstract
Spinal itch transmission has been reported to be mediated by at least two neuronal populations in spinal dorsal horn, neurons expressing brain-natriuretic peptide (BNP) receptor (Npra) and gastrin-releasing peptide (GRP) receptor (GRPR). Although Npra-expressing neurons were shown to be upstream of GRPR- expressing neurons in spinal itch transmission, the roles of BNP and GRP in the spinal neurotransmission of histamine-dependent and -independent itch remains unclear. Using in vivo electrophysiology and behavior analysis, this study examined the responses of chloroquine (histamine-independent pruritogen)-responsive and histamine-responsive dorsal horn neurons to spinal applications of BNP and GRP. Electrophysiologically, 9.5% of chloroquine-responsive neurons responded to BNP, 33.3% to GRP, and 4.8% to both, indicating that almost half of chloroquine-responsive neurons were unresponsive to both BNP and GRP. In contrast, histamine-responsive neurons did not respond to spinal BNP application, whereas 30% responded to spinal GRP application, indicating that 70% of histamine-responsive neurons were unresponsive to both BNP and GRP. Behavioral analyses showed differences in the time-course and frequency of scratching responses evoked by intrathecal BNP and GRP. These findings provide evidence that most BNP-Npra and GRP-GRPR signaling involve different pathways of spinal itch transmission, and that multiple neurotransmitters, in addition to BNP and GRP, are involved in spinal itch transmission. The electrophysiological results also suggest that spinal BNP contributes little to histaminergic itch directly.
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Abstract
UNLABELLED The gastrin-releasing peptide (GRP) and its receptor (GRPR) are important components of itch transmission. Upstream, but not downstream, aspects of GRPR signaling have been investigated extensively. We hypothesize that GRPR signals in part through the PI3Kγ/Akt pathway. We used pharmacological, electrophysiological, and behavioral approaches to further evaluate GRPR downstream signaling pathways. Our data show that GRP directly activates small-size capsaicin-sensitive DRG neurons, an effect that translates into transient calcium flux and membrane depolarization (∼ 20 mV). GRPR activation also induces Akt phosphorylation, a proxy for PI3Kγ activity, in ex vivo naive mouse spinal cords and in GRPR transiently expressing HEK293 cells. The intrathecal injection of GRP led to intense scratching, an effect largely reduced by either GRPR antagonists or PI3Kγ inhibitor. Scratching behavior was also induced by the intrathecal injection of an Akt activator. In a dry skin model of itch, we show that GRPR blockade or PI3Kγ inhibition reversed the scratching behavior. Altogether, these findings are highly suggestive that GRPR is expressed by the central terminals of DRG nociceptive afferents, which transmit itch via the PI3Kγ/Akt pathway. SIGNIFICANCE STATEMENT Itch is the most common symptom of the skin and is related to noncutaneous diseases. It severely impairs patients' quality of life when it becomes chronic and there is no specific or effective available therapy, mainly because itch pathophysiology is not completely elucidated. Our findings indicate that the enzyme PI3Kγ is a key central mediator of itch transmission. Therefore, we suggest PI3Kγ as an attractive target for the development of new anti-pruritic drugs. With this study, we take a step forward in our understanding of the mechanisms underlying the central transmission of itch sensation.
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